| 1. |
- Dyrek, Achrène, et al.
(författare)
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SO2, silicate clouds, but no CH4 detected in a warm Neptune
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625, s. 51-54
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Tidskriftsartikel (refereegranskat)abstract
- WASP-107b is a warm (approximately 740 K) transiting planet with a Neptune-like mass of roughly 30.5 M⊕ and Jupiter-like radius of about 0.94 RJ (refs. 1,2), whose extended atmosphere is eroding3. Previous observations showed evidence for water vapour and a thick, high-altitude condensate layer in the atmosphere of WASP-107b (refs. 4,5). Recently, photochemically produced sulfur dioxide (SO2) was detected in the atmosphere of a hot (about 1,200 K) Saturn-mass planet from transmission spectroscopy near 4.05 μm (refs. 6,7), but for temperatures below about 1,000 K, sulfur is predicted to preferably form sulfur allotropes instead of SO2 (refs. 8,9,10). Here we report the 9σ detection of two fundamental vibration bands of SO2, at 7.35 μm and 8.69 μm, in the transmission spectrum of WASP-107b using the Mid-Infrared Instrument (MIRI) of JWST. This discovery establishes WASP-107b as the second irradiated exoplanet with confirmed photochemistry, extending the temperature range of exoplanets exhibiting detected photochemistry from about 1,200 K down to about 740 K. Furthermore, our spectral analysis reveals the presence of silicate clouds, which are strongly favoured (around 7σ) over simpler cloud set-ups. Furthermore, water is detected (around 12σ) but methane is not. These findings provide evidence of disequilibrium chemistry and indicate a dynamically active atmosphere with a super-solar metallicity.
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| 2. |
- Parma, Valentina, et al.
(författare)
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More Than Smell—COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis
- 2020
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 45:7, s. 609-622
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Tidskriftsartikel (refereegranskat)abstract
- Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19–79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (−79.7 ± 28.7, mean ± standard deviation), taste (−69.0 ± 32.6), and chemesthetic (−37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.
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| 3. |
- Buchanan, E. M., et al.
(författare)
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The Psychological Science Accelerator's COVID-19 rapid-response dataset
- 2023
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Ingår i: Scientific Data. - : Springer Science and Business Media LLC. - 2052-4463. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- In response to the COVID-19 pandemic, the Psychological Science Accelerator coordinated three large-scale psychological studies to examine the effects of loss-gain framing, cognitive reappraisals, and autonomy framing manipulations on behavioral intentions and affective measures. The data collected (April to October 2020) included specific measures for each experimental study, a general questionnaire examining health prevention behaviors and COVID-19 experience, geographical and cultural context characterization, and demographic information for each participant. Each participant started the study with the same general questions and then was randomized to complete either one longer experiment or two shorter experiments. Data were provided by 73,223 participants with varying completion rates. Participants completed the survey from 111 geopolitical regions in 44 unique languages/dialects. The anonymized dataset described here is provided in both raw and processed formats to facilitate re-use and further analyses. The dataset offers secondary analytic opportunities to explore coping, framing, and self-determination across a diverse, global sample obtained at the onset of the COVID-19 pandemic, which can be merged with other time-sampled or geographic data.
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| 4. |
- Delrez, Laetitia, et al.
(författare)
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Transit detection of the long-period volatile-rich super-Earth nu(2) Lupi d with CHEOPS
- 2021
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Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; :5, s. 775-787
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Tidskriftsartikel (refereegranskat)abstract
- Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed access to the atmospheric, interior and orbital properties of the planetary companions. nu(2) Lupi (HD 136352) is a naked-eye (V = 5.78) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6 and 107.6 d via radial-velocity monitoring(1). The two inner planets (b and c) were recently found to transit(2), prompting a photometric follow-up by the brand new Characterising Exoplanets Satellite (CHEOPS). Here, we report that the outer planet d is also transiting, and measure its radius and mass to be 2.56 +/- 0.09 R-circle plus and 8.82 +/- 0.94 M-circle plus, respectively. With its bright Sun-like star, long period and mild irradiation (similar to 5.7 times the irradiation of Earth), nu(2) Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We refine the properties of all three planets: planet b probably has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the nu(2) Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
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| 5. |
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| 6. |
- Gad, Helge, et al.
(författare)
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MTH1 inhibition eradicates cancer by preventing sanitation of the dNTP pool
- 2014
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 508:7495, s. 215-221
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Tidskriftsartikel (refereegranskat)abstract
- Cancers have dysfunctional redox regulation resulting in reactive oxygen species production, damaging both DNA and free dNTPs. The MTH1 protein sanitizes oxidized dNTP pools to prevent incorporation of damaged bases during DNA replication. Although MTH1 is non-essential in normal cells, we show that cancer cells require MTH1 activity to avoid incorporation of oxidized dNTPs, resulting in DNA damage and cell death. We validate MTH1 as an anticancer target in vivo and describe small molecules TH287 and TH588 as first-in-class nudix hydrolase family inhibitors that potently and selectively engage and inhibit the MTH1 protein in cells. Protein co-crystal structures demonstrate that the inhibitors bindin the active site of MTH1. The inhibitors cause incorporation of oxidized dNTPs in cancer cells, leading to DNA damage, cytotoxicity and therapeutic responses in patient-derived mouse xenografts. This study exemplifies the non-oncogene addiction concept for anticancer treatment and validates MTH1 as being cancer phenotypic lethal.
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| 7. |
- Gaillard, Marie-José, 1953-, et al.
(författare)
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Holocene land-cover reconstructions for studies on land cover-climate feedbacks
- 2010
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 6, s. 483-499
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Tidskriftsartikel (refereegranskat)abstract
- The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover – CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/landcover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs “grassland” and “agricultural land” at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions.
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| 8. |
- Gasman, Danny, et al.
(författare)
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MINDS Abundant water and varying C/O across the disk of Sz 98 as seen by JWST/MIRI
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 679
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Tidskriftsartikel (refereegranskat)abstract
- Context. The Mid-InfraRed Instrument (MIRI) Medium Resolution Spectrometer (MRS) on board the James Webb Space Telescope (JWST) allows us to probe the inner regions of protoplanetary disks, where the elevated temperatures result in an active chemistry and where the gas composition may dictate the composition of planets forming in this region. The disk around the classical T Tauri star Sz 98, which has an unusually large dust disk in the millimetre with a compact core, was observed with the MRS, and we examine its spectrum here.Aims. We aim to explain the observations and put the disk of Sz 98 in context with other disks, with a focus on the H2O emission through both its ro-vibrational and pure rotational emission. Furthermore, we compare our chemical findings with those obtained for the outer disk from Atacama Large Millimeter/submillimeter Array (ALMA) observations.Methods. In order to model the molecular features in the spectrum, the continuum was subtracted and local thermodynamic equilibrium (LTE) slab models were fitted. The spectrum was divided into different wavelength regions corresponding to H2O lines of different excitation conditions, and the slab model fits were performed individually per region.Results. We confidently detect CO, H2O, OH, CO2, and HCN in the emitting layers. Despite the plethora of H2O lines, the isotopo-logue (H2O)-O-18 is not detected. Additionally, no other organics, including C2H2, are detected. This indicates that the C/O ratio could be substantially below unity, in contrast with the outer disk. The H2O emission traces a large radial disk surface region, as evidenced by the gradually changing excitation temperatures and emitting radii. Additionally, the OH and CO2 emission is relatively weak. It is likely that H2O is not significantly photodissociated, either due to self-shielding against the stellar irradiation, or UV shielding from small dust particles. While H2O is prominent and OH is relatively weak, the line fluxes in the inner disk of Sz 98 are not outliers compared to other disks.Conclusions. The relative emitting strength of the different identified molecular features points towards UV shielding of H2O in the inner disk of Sz 98, with a thin layer of OH on top. The majority of the organic molecules are either hidden below the dust continuum, or not present. In general, the inferred composition points to a sub-solar C/O ratio (<0.5) in the inner disk, in contrast with the larger than unity C/O ratio in the gas in the outer disk found with ALMA.
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| 9. |
- Gerkin, Richard C., et al.
(författare)
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Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms
- 2021
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0–100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19−; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19− groups exhibited smell loss, but it was significantly larger in C19+ participants (mean ± SD, C19+: −82.5 ± 27.2 points; C19−: −59.8 ± 37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC = 0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0–10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4 < OR < 10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.
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| 10. |
- Guldevall, Karolin, et al.
(författare)
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Microchip screening Platform for single cell assessment of NK cell cytotoxicity
- 2016
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Here, we report a screening platform for assessment of the cytotoxic potential of individual natural killer (NK) cells within larger populations. Human primary NK cells were distributed across a silicon-glass microchip containing 32,400 individual microwells loaded with target cells. Through fluorescence screening and automated image analysis, the numbers of NK and live or dead target cells in each well could be assessed at different time points after initial mixing. Cytotoxicity was also studied by time-lapse live-cell imaging in microwells quantifying the killing potential of individual NK cells. Although most resting NK cells (approximate to 75%) were non-cytotoxic against the leukemia cell line K562, some NK cells were able to kill several (>= 3) target cells within the 12-h long experiment. In addition, the screening approach was adapted to increase the chance to find and evaluate serial killing NK cells. Even if the cytotoxic potential varied between donors, it was evident that a small fraction of highly cytotoxic NK cells were responsible for a substantial portion of the killing. We demonstrate multiple assays where our platform can be used to enumerate and characterize cytotoxic cells, such as NK or T cells. This approach could find use in clinical applications, e.g., in the selection of donors for stem cell transplantation or generation of highly specific and cytotoxic cells for adoptive immunotherapy.
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| 11. |
- Hörberg, Thomas, 1979-, et al.
(författare)
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A parosmia severity index based on word-classification predicts olfactory abilities and impairment
- 2023
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Ingår i: European Archives of Oto-Rhino-Laryngology. - : Springer Nature. - 0937-4477 .- 1434-4726. ; 280:8, s. 3695-3706
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Tidskriftsartikel (refereegranskat)abstract
- Parosmia is an olfactory disorder that involves distortions of specific odors that may co-occur with anosmia, loss of smell of other odors. Little is known about which odors frequently trigger parosmia, and measures of parosmia severity are lacking. Here, we present an approach to understand and diagnose parosmia that is based on semantic properties (e.g., valence) of words describing odor sources (“fish”, “coffee”, etc.). Using a data-driven method based on natural language data, we identified 38 odor descriptors. Descriptors were evenly dispersed across an olfactory-semantic space, which was based on key odor dimensions. Parosmia patients (n = 48) classified the corresponding odors in terms of whether they trigger parosmic or anosmic sensations. We investigated whether these classifications are related to semantic properties of the descriptors. Parosmic sensations were most often reported for words describing unpleasant odors of inedibles that are highly associated to olfaction (e.g., “excrement”). Based on PCA modeling, we derived the Parosmia Severity Index—a measure of parosmia severity that can be determined solely from our non-olfactory behavioral task. This index predicts olfactory-perceptual abilities, self-reported olfactory impairment, and depression. We thus provide a novel approach for investigating parosmia and establishing its severity that does not require odor exposure. Our work may enhance our understanding of how parosmia changes over time and how it is expressed differently across individuals.
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| 12. |
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| 13. |
- Kalimo, Hannu, et al.
(författare)
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The Arctic AβPP mutation leads to Alzheimer's disease pathology with highly variable topographic deposition of differentially truncated Aβ
- 2013
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Ingår i: Acta neuropathologica communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 1:1, s. 60-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Arctic mutation (p.E693G/p.E22G)fs within the β-amyloid (Aβ) region of the β-amyloid precursor protein gene causes an autosomal dominant disease with clinical picture of typical Alzheimer's disease. Here we report the special character of Arctic AD neuropathology in four deceased patients.RESULTS: Aβ deposition in the brains was wide-spread (Thal phase 5) and profuse. Virtually all parenchymal deposits were composed of non-fibrillar, Congo red negative Aβ aggregates. Congo red only stained angiopathic vessels. Mass spectrometric analyses showed that Aβ deposits contained variably truncated and modified wild type and mutated Aβ species. In three of four Arctic AD brains, most cerebral cortical plaques appeared targetoid with centres containing C-terminally (beyond aa 40) and variably N-terminally truncated Aβ surrounded by coronas immunopositive for Aβx-42. In the fourth patient plaque centres contained almost no Aβ making the plaques ring-shaped. The architectural pattern of plaques also varied between different anatomic regions. Tau pathology corresponded to Braak stage VI, and appeared mainly as delicate neuropil threads (NT) enriched within Aβ plaques. Dystrophic neurites were scarce, while neurofibrillary tangles were relatively common. Neuronal perikarya within the Aβ plaques appeared relatively intact.CONCLUSIONS: In Arctic AD brain differentially truncated abundant Aβ is deposited in plaques of variable numbers and shapes in different regions of the brain (including exceptional targetoid plaques in neocortex). The extracellular non-fibrillar Aβ does not seem to cause overt damage to adjacent neurons or to induce formation of neurofibrillary tangles, supporting the view that intracellular Aβ oligomers are more neurotoxic than extracellular Aβ deposits. However, the enrichment of NTs within plaques suggests some degree of intra-plaque axonal damage including accumulation of hp-tau, which may impair axoplasmic transport, and thereby contribute to synaptic loss. Finally, similarly as the cotton wool plaques in AD resulting from exon 9 deletion in the presenilin-1 gene, the Arctic plaques induced only modest glial and inflammatory tissue reaction.
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| 14. |
- Lindroos, Robert, 1980-, et al.
(författare)
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Perceptual odor qualities predict successful odor identification in old age
- 2022
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 47
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Tidskriftsartikel (refereegranskat)abstract
- Odor identification is a common assessment of olfaction, and it is affected in a large number of diseases. Identification abilities decline with age, but little is known about whether there are perceptual odor features that can be used to predict identification. Here, we analyzed data from a large, population-based sample of 2,479 adults, aged 60 years or above, from the Swedish National study on Aging and Care in Kungsholmen. Participants performed both free and cued odor identification tests. In a separate experiment, we assessed perceived pleasantness, familiarity, intensity, and edibility of all odors in the first sample, and examined how odor identification performance is associated with these variables. The analysis showed that high-intensity odors are easier to identify than low-intensity odors overall, but also that they are more susceptible to the negative repercussions of old age. This result indicates that sensory decline is a major aspect of age-dependent odor identification impairment, and suggests a framework where identification likelihood is proportional to the perceived intensity of the odor. Additional analyses further showed that high-performing individuals can discriminate target odors from distractors along the pleasantness and edibility dimensions and that unpleasant and inedible odors show smaller age-related differences in identification. Altogether, these results may guide further development and optimization of brief and efficient odor identification tests as well as influence the design of odorous products targeted toward older consumers.
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| 15. |
- Myers-Smith, Isla H., et al.
(författare)
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Complexity revealed in the greening of the Arctic
- 2020
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-678X .- 1758-6798. ; 10:2, s. 106-117
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Tidskriftsartikel (refereegranskat)abstract
- As the Arctic warms, vegetation is responding, and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most important large-scale ecological responses to global climate change. However, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable and inherently scale-dependent than previously thought. Here we summarize the complexities of observing and interpreting high-latitude greening to identify priorities for future research. Incorporating satellite and proximal remote sensing with in-situ data, while accounting for uncertainties and scale issues, will advance the study of past, present and future Arctic vegetation change.
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| 16. |
- Olofsson, Thomas, 1968-, et al.
(författare)
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Små steg har betydelse
- 2015
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Ingår i: Västerbottenskuriren. ; , s. 7-
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 17. |
- Olofsson, Thomas, 1968-, et al.
(författare)
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Viktiga små steg för bättre klimat
- 2014
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Ingår i: Västerbottenskuriren. - : Västerbottenskuriren. - 1104-0246. ; , s. 6-
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 18. |
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| 19. |
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| 20. |
- Adiels, Martin, 1976, et al.
(författare)
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Postprandial accumulation of chylomicrons and chylomicron remnants is determined by the clearance capacity.
- 2012
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Ingår i: Atherosclerosis. - : Elsevier BV. - 1879-1484 .- 0021-9150. ; 222:1, s. 222-8
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Tidskriftsartikel (refereegranskat)abstract
- Objective To better understand the postprandial clearance of triglyceride-rich lipoproteins (TRLs) and its relation to the fasting kinetics of TRLs. Methods Two studies were performed on 30 male subjects: a fasting kinetic study to determine the fasting secretion and clearance rates of apolipoprotein B (apoB) 100 and triglycerides in the very low-density lipoprotein 1 and 2 (VLDL1 and VLDL2) fractions; and a postprandial study to determine the postprandial accumulation of apoB48, apoB100 and triglycerides in the chylomicron, VLDL1 and VLDL2 fractions. Results from these two studies were combined to characterize the postprandial clearance of TRLs in a physiologically relevant setting. Results Our results show that postprandial accumulation of the apoB48-carrying chylomicrons can be predicted from the clearance capacity of the lipolytic pathway, determined in the fasting state. Furthermore, we show that chylomicrons and VLDL1 particles are not cleared equally by the lipoprotein lipase pathway, and that chylomicrons seem to be the preferred substrate. Subjects with a rapid fasting lipid metabolism accumulate lower levels of postprandial triglycerides with less accumulation of apoB100 in the VLDL1 fraction and a faster transfer of apoB100 into the VLDL2 fraction. In contrast, fasting VLDL1 secretion does not predict postprandial triglyceride accumulation. Conclusions Non-fasting triglyceride levels have recently been identified as a major predictor of future cardiovascular events. Here we show that the capacity of the lipolytic pathway is a common determinant of both the fasting and non-fasting triglyceride levels and may thus play an important role in the development of dyslipemia and atherosclerosis.
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| 21. |
- Akinsanmi, B., et al.
(författare)
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The tidal deformation and atmosphere of WASP-12 b from its phase curve
- 2024
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
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Tidskriftsartikel (refereegranskat)abstract
- Context. Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets, their atmospheres, and interiors at extreme conditions. WASP-12 b stands out as an archetype of this class of exoplanets, with a close-in orbit around its star that results in intense stellar irradiation and tidal effects. Aims. The goals are to measure the planet's tidal deformation, atmospheric properties, and also to refine its orbital decay rate. Methods. We performed comprehensive analyses of the transits, occultations, and phase curves of WASP-12b by combining new CHEOPS observations with previous TESS and Spitzer data. The planet was modeled as a triaxial ellipsoid parameterized by the second-order fluid Love number of the planet, h2, which quantifies its radial deformation and provides insight into the interior structure. Results. We measured the tidal deformation of WASP-12b and estimated a Love number of h2 = 1.55- 0.49+0.45 (at 3.2σ) from its phase curve. We measured occultation depths of 333 ± 24 ppm and 493 ± 29 ppm in the CHEOPS and TESS bands, respectively, while the nightside fluxes are consistent with zero, and also marginal eastward phase offsets. Our modeling of the dayside emission spectrum indicates that CHEOPS and TESS probe similar pressure levels in the atmosphere at a temperature of ~2900 K. We also estimated low geometric albedos of Ag = 0.086 ± 0.017 and Ag = 0.01 ± 0.023 in the CHEOPS and TESS passbands, respectively, suggesting the absence of reflective clouds in the high-temperature dayside of the planet. The CHEOPS occultations do not show strong evidence for variability in the dayside atmosphere of the planet at the median occultation depth precision of 120 ppm attained. Finally, combining the new CHEOPS timings with previous measurements refines the precision of the orbital decay rate by 12% to a value of - 30.23 ± 0.82 ms yr- 1, resulting in a modified stellar tidal quality factor of Q′∗ = 1.70 ± 0.14 × 105. Conclusions. WASP-12 b becomes the second exoplanet, after WASP-103b, for which the Love number has been measured from the effect of tidal deformation in the light curve. However, constraining the core mass fraction of the planet requires measuring h2 with a higher precision. This can be achieved with high signal-to-noise observations with JWST since the phase curve amplitude, and consequently the induced tidal deformation effect, is higher in the infrared.
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| 22. |
- Alerstam, Thomas, et al.
(författare)
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Hypotheses and tracking results about the longest migration : The case of the arctic tern
- 2019
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9:17, s. 9511-9531
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Tidskriftsartikel (refereegranskat)abstract
- The arctic tern Sterna paradisaea completes the longest known annual return migration on Earth, traveling between breeding sites in the northern arctic and temperate regions and survival/molt areas in the Antarctic pack-ice zone. Salomonsen (1967, Biologiske Meddelelser, Copenhagen Danske Videnskabernes Selskab, 24, 1) put forward a hypothetical comprehensive interpretation of this global migration pattern, suggesting food distribution, wind patterns, sea ice distribution, and molt habits as key ecological and evolutionary determinants. We used light-level geolocators to record 12 annual journeys by eight individuals of arctic terns breeding in the Baltic Sea. Migration cycles were evaluated in light of Salomonsen's hypotheses and compared with results from geolocator studies of arctic tern populations from Greenland, Netherlands, and Alaska. The Baltic terns completed a 50,000 km annual migration circuit, exploiting ocean regions of high productivity in the North Atlantic, Benguela Current, and the Indian Ocean between southern Africa and Australia (sometimes including the Tasman Sea). They arrived about 1 November in the Antarctic zone at far easterly longitudes (in one case even at the Ross Sea) subsequently moving westward across 120–220 degrees of longitude toward the Weddell Sea region. They departed from here in mid-March on a fast spring migration up the Atlantic Ocean. The geolocator data revealed unexpected segregation in time and space between tern populations in the same flyway. Terns from the Baltic and Netherlands traveled earlier and to significantly more easterly longitudes in the Indian Ocean and Antarctic zone than terns from Greenland. We suggest an adaptive explanation for this pattern. The global migration system of the arctic tern offers an extraordinary possibility to understand adaptive values and constraints in complex pelagic life cycles, as determined by environmental conditions (marine productivity, wind patterns, low-pressure trajectories, pack-ice distribution), inherent factors (flight performance, molt, flocking), and effects of predation/piracy and competition.
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| 23. |
- Allard, Ingrid, 1986-, et al.
(författare)
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A methodology to investigate the building energy performance gap
- 2015
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In order to evaluate compliance with requirements on building energy performance, it is necessary to find strategies to process discrepancies from the results of forward simulations in the design stage and of measurements in the operated stage. The gap between designed performance and measured performance is referred to as the “performance gap”. It can be divided into a procurement gap (between intended design and verified performance) and an operational gap (between verified performance and non-normalized measurements). In this work we introduced a methodology for performance gap analysis, based on separating the procurement- and operational gap. An important component to do this is calibrations of calculations using measured data. The suggested methodology allows for more detailed verifications of building energy performance and can be used to study how indicators reflect the performance gap. The proposed methodology is tested using data from a well-documented and measured operated single family building, in sub-arctic climate in Sweden.The indicators studied in the verification were carefully analyzed. The methodology was found reliable based on the obtained results and a sensitivity analysis. An overall observation is that the applicability of the methodology depends on the accuracy of the hybrid method. The accuracy of the performance gap analysis per definition depends on the available information of the operated building, and consequently to access to extensive measured data.
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| 24. |
- Allard, Ingrid
(författare)
-
Achieving building energy performance : requirements and evaluation methods for residential buildings in Sweden, Norway, and Finland
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Building energy performance has always been important in the cold climate of Sweden, Norway and Finland. To meet the goal that all new buildings should be nearly zero-energy buildings by 2020, set in the EU directive 2010/31/EU [1] on the energy performance of buildings (EPBD recast), the building sector in Europe now faces a transition towards buildings with improved energy performance. In such a transition, a discussion is needed about the objective of the improvement – why, or to what end, the building energy performance should be improved. The objective of improving building energy performance is often a political decision, but scientific research can contribute with knowledge on how the objectives can be achieved.This thesis addresses how the indicators used in the requirements used to achieve building energy performance in Sweden, Norway, and Finland, and the methods used to evaluate these requirements, reflect building energy performance. It also addresses difficulties in achieving comparable and verifiable indicators in evaluations of building energy performance. The research objective has two parts: to review, compare, and discuss (i) requirements and (ii) evaluation methods used to achieve energy performance of residential buildings in Sweden, Norway and Finland. The work in this thesis includes reviews of the requirements used in national building codes and passive house criteria to achieve building energy performance, of methods used to evaluate compliance with such requirements, and of methods used specifically to evaluate the indicator Envelope Air Tightness. The results show that different sets of indicators are used to achieve building energy performance in the studied building codes and passive house criteria. The methods used to evaluate compliance with requirements used to achieve building energy performance are also different, but calculation methods are generally more often used than measurement methods. The calculation- and measurement methods used are often simple. A methodology to analyze the deviation between predictions- and measurements of building energy performance (the performance gap) was developed, to investigate the effects of different evaluation methods on different indicators used to achieve building energy performance. The methodology was tested in a case-study. This study indicated that the choice of method affects which parts of the performance gap reflected in the indicators Supplied Energy (see Terminology), Net Energy (see Terminology), and Overall U-value. Among the reviewed methods to evaluate air tightness, the Fan/Blower Door Pressurization is well known and preferred by professionals in the field. The results in this thesis may be useful when choosing indicators and evaluation methods to achieve different objectives of improving building energy performance and in the quest towards comparable and verifiable indicators used to achieve building energy performance.
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| 25. |
- Allard, Ingrid, 1986-, et al.
(författare)
-
Energy evaluation methods for residential buildings in Nordic countries
- 2012
-
Ingår i: Proceeding of the Technoport Conference. - : Elsevier.
-
Konferensbidrag (refereegranskat)abstract
- To meet the goals of the directive 2010/31/EU on the energy performance of buildings, the building sector in Europe now faces a transition towards more energy efficient buildings. Research and development of new energy solutions and technology will be necessary for the transition and the importance of measuring and evaluating building energy performance increases. This paper attempts to review and evaluate different methods that are commonly used to analyze energy performance in residential buildings in Nordic countries, primarily in Sweden, Norway and Finland. A short international review of regulations is also included. Some advantages and disadvantages of each method are discussed, as well as commonly used methods in the three countries. Although the three Nordic countries have similar climate conditions and building traditions, the study shows that there exist relatively large variations in defining parameters related to energy performance in residential buildings, such as energy use, heated area, and climate zones. The outcome of the regulations could be investigated by adapting the codes on a selected set of buildings. Common analyzing methods, or parts of methods, are found to be used in several countries. These aspects may be considered in further work to develop more accurate and easily comparable methods to evaluate energy performance for residential buildings in cold climate.
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| 26. |
- Allard, Ingrid, 1986-, et al.
(författare)
-
Energy evaluation of residential buildings : Performance gap analysis incorporating uncertainties in the evaluation methods
- 2018
-
Ingår i: Building Simulation. - : Tsinghua University Press. - 1996-3599 .- 1996-8744. ; 11:4, s. 725-737
-
Tidskriftsartikel (refereegranskat)abstract
- Calculation and measurement-based energy performance evaluations of the same building often provide different results. This difference is referred as "the performance gap". However, a large performance gap may not necessarily mean that there are flaws in the building or deviations from the intended design. The causes for the performance gap can be analysed by calibrating the simulation model to measured data. In this paper, an approach is introduced for verifying compliance with energy performance criteria of residential buildings. The approach is based on a performance gap analysis that takes the uncertainties in the energy evaluation methods into consideration. The scope is to verify building energy performance through simulation and analysis of measured data, identifying any performance gap due to deviations from the intended design or flaws in the finished building based on performance gap analysis. In the approach, a simulation model is calibrated to match the heat loss coefficient of the building envelope [kWh/K] instead of the measured energy. The introduced approach is illustrated using a single-family residential building. The heat loss coefficient was found useful towards identifying any deviations from the intended design or flaws in the finished building. The case study indicated that the method uncertainty was important to consider in the performance gap analysis and that the proposed approach is applicable even when the performance gap appears to be non-existing.
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| 27. |
- Allard, Ingrid, 1986-, et al.
(författare)
-
Energy performance criteria for residential buildings : A comparison of Finnish, Norwegian, Swedish, and Russian building codes
- 2021
-
Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 250
-
Tidskriftsartikel (refereegranskat)abstract
- Building code are considered to be an effective policy tool to reduce energy use in buildings. In practice, national priorities influence the indicators and criteria adopted in the building codes. Consequently, neighbouring countries with similar climate conditions may use different criteria in their building codes to regulate the energy performance. In this paper, the energy performance criteria and their relative stringency in the latest residential building codes of Finland, Norway, Sweden and Russia are compared. The study is based on energy performance evaluations of one single-family building and one multi-family building, located in the north of Sweden. Both buildings complied with the Norwegian and Russian building code. However, the buildings did not comply with the specific fan power and heat loss criteria in the Finnish building code. Additionally, the single-family building did not comply with the specific primary energy and electric powerdemand criteria in the Swedish building code when heated by an electric heater. The national standard input data were found to have a large influence on the buildings’ compliance with the studied energy use criteria. Policy implications of the results are discussed.
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| 28. |
- Allard, Ingrid, et al.
(författare)
-
Energy performance indicators in the Swedish building procurement process
- 2017
-
Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 9:10
-
Tidskriftsartikel (refereegranskat)abstract
- In Sweden, all new buildings need to comply with the National Board of Housing, Building and Planning’s requirement on specific purchased energy (kWh/m2). Accordingly, this indicator is often used to set design criteria in the building procurement process. However, when energy use is measured in finished buildings, the measurements often deviate significantly from the design calculations. The measured specific purchased energy does not necessarily reflect the responsibility of the building contractor, as it is influenced by the building operation, user behavior and climate. Therefore, Swedish building practitioners may prefer other indicators for setting design criteria in the building procurement process. The aim of this study was twofold: (i) to understand the Swedish building practitioners’ perspectives and opinions on seven building energy performance indicators (envelope air leakage, U-values for different building parts, average U-value, specific heat loss, heat loss coefficient, specific net energy, and specific purchased energy); and (ii) to understand the consequences for the energy performance of multi-family buildings of using the studied indicators to set criteria in the procurement process. The study involved a Delphi approach and simulations of a multi-family case study building. The studied indicators were discussed in terms of how they may meet the needs of the building practitioners when used to set building energy performance criteria in the procurement process.
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| 29. |
- Allard, Ingrid, 1986-, et al.
(författare)
-
Methods for air tightness analysis for residential buildings in Nordic countries
- 2012
-
Ingår i: Methods for air tightness analysis forresidential buildings in Nordic countries. - Southampton : WIT Press. - 9781845646141 ; , s. 311-322
-
Konferensbidrag (refereegranskat)abstract
- Envelope air tightness is one factor that has impact on the energy performance ofbuildings. The goals of the directive 2010/31/EU, on energy performance ofbuildings, raise the importance of building energy performance analysis in theprocess. Measurements of air tightness can be useful both when evaluatingbuilding energy performance and developing new building techniques. The aimof this paper is to review and evaluate methods to measure air tightness in bothnew and existing residential buildings in Sweden, Norway and Finland, based onan international literature study and a survey. The methods are categorized basedon a number of criteria to determine their suitability in different situations.Advantages and disadvantages of the methods are discussed, as well ascommonly used methods in the three countries. The review shows that thestandard ISO 9972 is used for verification in all three countries, but alternativesexist that might be more suitable in certain situations. Simpler methods are usedin the building process to increase air tightness. To achieve a comparablemeasurement, both common methods and commonly defined units are needed.
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| 30. |
- Allard, Ingrid, et al.
(författare)
-
Methods for energy analysis of residential buildings in Nordic countries
- 2013
-
Ingår i: Renewable & sustainable energy reviews. - : Pergamon-Elsevier Science. - 1364-0321 .- 1879-0690. ; 22, s. 306-318
-
Forskningsöversikt (refereegranskat)abstract
- To meet the goals of the directive 2010/31/EU on the energy performance of buildings, the building sector in Europe now faces a transition towards more energy efficient buildings. Research and development of new energy solutions and technology will be necessary for the transition and the importance of analyzing building energy performance increases. This paper aims to review and evaluate different methods that are commonly used to analyze energy performance in residential buildings in Nordic countries, primarily in Sweden, Norway and Finland. A short international review of regulations is also included. The goal is to find commonly used methods and possibilities for the future. The introduced methods are summarized, categorized and compared based on their advantages and disadvantages. Although the three Nordic countries have similar climate conditions and building traditions, the review shows relatively large variations in the definitions of energy performance for residential buildings, as well as variations in how measurements and calculations are used in the methods for energy performance analysis. In the conducted review, methods, or parts of methods, are also found to be used. The methods used to analyze energy performance are found to be more similar than the concepts of energy performance itself in the three countries. These aspects may be considered in further work to develop an international policy practice for energy performance of residential buildings in cold climate.
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| 31. |
- Allard Stolterman, Ingrid, 1986-
(författare)
-
Regulating energy performance of residential buildings in cold climate : a study of indicators, criteria, and evaluation methods
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Building energy performance has been important in Fennoscandia ever since the early vernacular houses, to combat the cold climate. Due to EU directive 2010/31/EU on the energy performance of buildings (EPBD recast), building energy performance has become even more relevant in northern Europe the last decade. Objectives for improving building energy performance may include reducing cost and CO2-emissions, increasing energy independency, and improving the indoor climate. Different indicators, criteria, and evaluations methods may be used to reach these objectives. This dissertation addresses indicators, criteria, and evaluation methods used to regulate energy performance of residential buildings in Sweden, Norway, Finland, and Russia. Four research objectives are covered: (RO1) comparing criteria and evaluation methods used to regulate energy performance of residential buildings in Sweden, Norway, and Finland, (RO2) studying the perspective of professionals with experience in building energy performance evaluation on (a) methods for evaluating envelope air leakage of residential buildings in Sweden and Finland and (b) potential energy performance indicators in the Swedish procurement process of multi-family buildings, (RO3) developing an approach for analysing the performance gap between design predictions and measurements that can be used to verify compliance with requirements on building energy use in practice, and (RO4) comparing the stringency of the energy performance criteria for residential buildings between the Swedish, Norwegian, Finnish, and Russian national building code. Many differences were found between how energy performance of residential buildings was regulated in the four countries. In Sweden, measurements were used more for evaluating building energy performance than in the other countries. As of 1st January 2020, the Finnish building code was characterized by its focus on the building heat loss and stringent energy performance criteria compared to the other countries. The Norwegian building code was characterized by a relatively narrow system perspective on energy performance, with no regulation of the energy production efficiency or energy source. The Russian building code also had a narrow system perspective but was also characterized by its focus on the form factor – the relationship between building volume and enclosing area. The practitioners wanted to minimize the influence from building operation and user behaviour on energy performance evaluations in the Swedish building procurement process of multi-family buildings. Hence, they preferred component-focused indicators or indicators with a narrow system boundary. An approach has been developed for analyzing the performance gap between design phase predictions and measurements. The approach can be used to verify the finished building’s energy performance, with minimal influence from occupant behavior and building operation.
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| 32. |
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| 33. |
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| 34. |
- Alonso, R., et al.
(författare)
-
No random transits in CHEOPS observations of HD 139139 *,**
- 2023
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 680
-
Tidskriftsartikel (refereegranskat)abstract
- Context . The star HD 139139 (a.k.a. ‘the Random Transiter’) is a star that exhibited enigmatic transit-like features with no apparent periodicity in K2 data. The shallow depth of the events (-200 ppm - equivalent to transiting objects with radii of -1.5 R⊕ in front of a Sun-like star) and their non-periodicity constitute a challenge for the photometric follow-up of this star. Aims . The goal of this study is to confirm with independent measurements the presence of shallow, non-periodic transit-like features on this object. Methods . We performed observations with CHEOPS for a total accumulated time of 12.75 days, distributed in visits of roughly 20 h in two observing campaigns in years 2021 and 2022. The precision of the data is sufficient to detect 150 ppm features with durations longer than 1.5 h. We used the duration and times of the events seen in the K2 curve to estimate how many events should have been detected in our campaigns, under the assumption that their behaviour during the CHEOPS observations would be the same as in the K2 data of 2017. Results . We do not detect events with depths larger than 150 ppm in our data set. If the frequency, depth, and duration of the events were the same as in the K2 campaign, we estimate the probability of having missed all events due to our limited observing window would be 4.8%. Conclusions . We suggest three different scenarios to explain our results: 1) Our observing window was not long enough, and the events were missed with the estimated 4.8% probability. 2) The events recorded in the K2 observations were time critical, and the mechanism producing them was either not active in the 2021 and 2022 campaigns or created shallower events under our detectability level. 3) The enigmatic events in the K2 data are the result of an unidentified and infrequent instrumental noise in the original data set or its data treatment.
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| 35. |
- Andersson, Agnes, et al.
(författare)
-
Headache Before and After Endoscopic Transsphenoidal Pituitary Tumor Surgery: A Prospective Study
- 2022
-
Ingår i: Journal of Neurological Surgery Part B-Skull Base. - : Georg Thieme Verlag KG. - 2193-6331 .- 2193-634X. ; 83:suppl. 2
-
Tidskriftsartikel (refereegranskat)abstract
- Objective Headache is a common symptom among patients with pituitary tumors, as it is in the general population. The aim of the study was to investigate headache as a symptom in patients with pituitary tumors before and 6 months after endoscopic transsphenoidal surgery (TSS). Design This is a prospective observational cohort study. Setting This study was conducted at university tertiary referral hospital. Participants A total of 110 adult patients underwent endoscopic TSS for pituitary tumors. Main Outcome Measures The Migraine Disability Assessment (MIDAS) questionnaire was used before and 6 months after surgery for the assessment of headache. Clinical variables with potential influence on headache were analyzed. Results Sixty-eight (62%) patients experienced headaches at least once during the 3 months before surgery. Thirty (27%) patients reported disabling headache before surgery, with younger age being an independent associated factor ( p <0.001). In patients with disabling headache before surgery, the median (interquartile range) MIDAS score improved from 78 (27-168) to 16 (2-145; p =0.049), headache frequency decreased from 45 (20-81) to 14 (4-35) days ( p =0.009), and headache intensity decreased from 6 (5-8) to 5 (4-7) ( p =0.011) after surgery. In total, 16 of the 30 (53%) patients reported a clinically relevant improvement and five (17%) a clinically relevant worsening. Four (5%) patients developed new disabling headache. No predictor for postoperative improvement of headache was identified. Conclusion In this prospective study, the results show that disabling headache improves following endoscopic TSS in a subset of patients with pituitary tumors. However, no predictive factors for improvement could be identified.
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| 36. |
- Andersson, Staffan, 1952-, et al.
(författare)
-
Building performance based on measured data
- 2011
-
Ingår i: World Renewable Energy Congress – Sweden, 8–13 May, 2011, Linköping, Sweden. - Linköping : Linköping University Electronic Press. - 9789173930703 ; , s. 899-906
-
Konferensbidrag (refereegranskat)abstract
- With increasing liability for builders, the need for evaluation methods that focuses on the building’s performance and thus excludes the impact from residents’ behavior increases. This is not only of interest for new buildings but also when retrofitting existing buildings in order to reduce energy end-use. The investigation in this paper is based on extensive measurements on two fairly representative type of buildings, a single family building in Ekerö, Stockholm built 2000 and two apartment buildings in Umeå (1964) in order to extract key energy performance parameters such as the building’s heat loss coefficient, heat transfer via the ground and heat gained from the sun and used electricity. With access to pre-processed daily data from a 2-month periods, located close to the winter solstice, a robust estimate of the heat loss coefficient was obtained based on a regression analysis. For the single family building the variation was within 1% and for the two heavier apartment buildings an average variation of 2%, with a maximum of 4%, between different analyzed periods close to the winter solstice. The gained heating from the used electricity in terms of a gain factor could not be unambiguously extracted and therefore could only a range for the heat transfer via ground be estimated. The estimated range for the transfer via ground for the two apartment buildings were in very good agreement with those calculated according to EN ISO 13 370 and corresponded to almost 10% of the heating demand at the design temperature. For the single family building with an insulated slab and parts of the walls below ground level, the calculations gave slightly higher transfer than what was obtained from the regression analysis. For the estimated gained solar radiation no comparison has been possible to make, but the estimated gain exhibited an expected correlation with the global solar radiation data that was available for the two apartment buildings.
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| 37. |
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| 38. |
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| 39. |
- Anund Vogel, Jonas, et al.
(författare)
-
Buildings post corona
- 2023
-
Ingår i: The REHVA European HVAC Journal. - 1307-3729. ; 59:2, s. 19-21
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Buildings Post Corona is a Swedish collaborative research project between Chalmers, KTH Royal Institute of Technology, Lund, and Umeå Universities. The project supports the building sector in designing and maintaining sustainable buildings with a healthy and good indoor environment. The COVID-19 crisis has stressed the importance and urge of this research.The scope of the project is to develop a methodology for the operation and design of buildings with an indoor environment that meets future health and climate challenges. The project’s overall goal is to establish an interdisciplinary platform to document existing experiences and knowledge and to gain new knowledge required for good building design and operation.
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| 40. |
- Anund Vogel, Jonas, et al.
(författare)
-
Enbart avstånd och handhygien räcker inte
- 2023
-
Ingår i: Fastighetstidningen. - 0348-5552.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- I denna debattartikel lyfter sex forskare frågan att myndigheter och branschorganisationer delvis gav olika råd kring åtgärder för att begränsa risken för smittspridning inomhus. För att klara nästa pandemi krävs bättre samordning av riktlinjer kring ventilation och luftkvalitet.
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| 41. |
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| 42. |
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| 43. |
- Azizi, Shoaib, 1989-
(författare)
-
A multi-method assessment to support energy efficiency decisions in existing residential and academic buildings
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rapid decarbonization of building stock is essential for the energy transition required to mitigate climate change and limit the global temperature rise below 1.5 °C. The decision-making for the adoption of energy efficiency measures (EEMs) is often complex and involves lasting consequences and risks. The strategy to direct and support the decision makers can significantly increase the adoption rate of EEMs in buildings. This Ph.D. project focuses on facilitating sustainability improvement in buildings by supporting the decision makers who are accountable for the consequences of adopting the EEMs. Energy efficiency improvement is decided and managed differently in various types of buildings and contexts and encounters different challenges and opportunities. Accordingly, it is required to understand the needs to select adequate strategies and to devise effective supporting interventions for energy efficiency improvement.The owners of single-family houses are often the occupants who are in charge of the most decisions to improve energy efficiency in their dwellings. The situation is rather different in multi-family buildings and academic buildings in which organizational management adds more complexity and the decisions affect various stakeholders. The studies in this project are based on qualitative and quantitative data collected from single-family houses, multi-family buildings, and university buildings in northern Sweden. Surveys were used to elicit the decision makers' perceptions of different types of buildings. Moreover, sensor data from university buildings were used in the case studies to develop informative metrics for space use efficiency and to analyze the effect of sensor positioning on monitored data.The initial work involved understanding the opportunities and challenges of improving energy efficiency in buildings and the tradeoffs between the perceived benefits and barriers. This part of the thesis provided the foundation and inspiration for the rest of the project, including investigating how to bundle several measures and use information and communication technologies (ICT) for building sustainability. The findings show lack of information and evidence that could justify the beneficial outcomes of EEMs is a major barrier for effective decision-making. Clear information on potential improvements allows sharing the responsibilities among different stakeholders and increases the management capacity to handle projects and adopt EEMs. Using feedback tools (for example, space use and/or energy use visualizations) might be an effective strategy to influence decision makers.Various studies incorporated in this multidisciplinary Ph.D. thesis develop and investigate strategies to support decision makers to improve energy efficiency in buildings. The findings provide insights to policymakers and businesses to devise intervention strategies for energy efficiency in buildings.
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| 44. |
- Azizi, Shoaib, 1989-, et al.
(författare)
-
Adoption of Energy Efficiency Measures in Renovation of Single-Family Houses : A Comparative Approach
- 2020
-
Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:22
-
Tidskriftsartikel (refereegranskat)abstract
- Inclusion of energy efficiency measures (EEMs) in the renovation of the single-family housing stock can unlock the potential for much-needed energy efficiency to tackle climate change. Energy renovation (ER) in single-family houses is often promoted as an aggregate process, and EEMs are treated homogenously without sufficient attention to their differences. This study applies a comparative analysis on common EEMs using chi-square test to investigate the influence of factors already found affecting the implementation of ER. This paper addresses the “personal” and “house-related” factors influencing the adoption of EEMs regardless of motives or barriers leading the adopters’ decisions. This strategy is useful to highlight the contexts leading to an increase in the adoption rate of different EEMs. The analysis is based on a questionnaire survey mailed in spring 2017 to 1550 single-family homeowners in the northern region of Sweden. Approximately 60% of respondents showed interest in adopting at least one EEM if they implement a major renovation. About 46% of respondents stated to have at least one indoor environmental problem (IEP) in their houses, and IEPs are found to have significant relations with homeowners’ interest to adopt several different EEMs. The policy implications related to different EEMs are discussed.
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| 45. |
- Azizi, Shoaib, 1989-, et al.
(författare)
-
Analysing the house-owners’ perceptions on benefits and barriers of energy renovation in Swedish single-family houses
- 2019
-
Ingår i: Energy and Buildings. - : Elsevier. - 0378-7788 .- 1872-6178. ; 198, s. 187-196
-
Tidskriftsartikel (refereegranskat)abstract
- Single-family houses offer a large potential for energy savings by energy renovation (ER). Homeowners’ motivation to implement ER derives from the benefits and barriers they perceive. Benefits are the positive consequences that can motivate homeowners to act and barriers are the challenges that demotivate them to undertake ER. Different benefits and barriers do not homogenously affect every homeowner. Identifying motivating benefits and demotivating barriers for each specific group among homeowners can shed lights on ER decision-making and enable policies that are more effective. The objective of this study is to contextualize the implementation of ER by understanding how the perceived benefits and barriers influence homeowners. This study links the expected consequences, which are benefits and barriers to the influential factors on ER, which are used to group the homeowners.The analysis is based on a questionnaire survey mailed to 1550 owners of single-family houses in northern Sweden. The perceptions of homeowners on benefits and barriers of ER are significantly different between the groups that are motivated and unmotivated to implement ER. Despite the perceived importance of some of the benefits such as energy cost reduction, they may not be determinative for the homeowners’ decision to undertake ER. The homeowners are more likely to implement ER for reasons other than energy use reduction such as for improving the indoor environment. The barriers such as the difficulty of finding a low-interest loan and reliable information sources are found to impede the intention to implement ER among different groups. Policy implications to facilitate ER in single-family houses are discussed.
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| 46. |
- Azizi, Shoaib, et al.
(författare)
-
Application of Internet of Things in academic buildings for space use efficiency using occupancy and booking data
- 2020
-
Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 186
-
Tidskriftsartikel (refereegranskat)abstract
- Environmental sustainability in academic buildings can be improved with management interventions such as improving space use efficiency supported by large data from the Internet of Things (IoT). Due to the potentials, the interest in the use of IoT tools for facility management is high among universities. However, empirical studies on this topic are scarce. To address the knowledge gap in this area, this study proposes and examines a process model with steps to measure space use and to improve space use efficiency by IoT tools in academic buildings. The applicability of the model is investigated in 8 lecture halls in a university building by using occupancy and booking data from IoT tools. Four space use indicators are developed to visualize the data and quantify space use, and based on them, the strategies and interventions for space use efficiency are proposed and discussed.
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| 47. |
- Azizi, Shoaib, et al.
(författare)
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Application of occupancy and booking information to optimize space and energy use in higher education institutions
- 2020
-
Ingår i: E3S Web of Conferences. - : EDP Sciences. - 2267-1242. ; 172
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Tidskriftsartikel (refereegranskat)abstract
- Building in higher education institutions (HEIs) are characterized as energy intensive Experience from practice showing large discrepancies between predicted and actual energy performance. The deviation can sometimes reach 100%. Explanations often originate from occupant’s behaviour along with building operation. IoT-based smart tools can provide extensive information about building usage to improve the building management, often associates with opportunities, for significant energy saving. The analysis in this study investigate space use based on occupancy and booking information in eight different lecture rooms at Umeå University. The results suggest interventions for significant saving potentials, such as modification of access permission and closing down redundant lecture rooms.
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| 48. |
- Azizi, Shoaib, 1989-, et al.
(författare)
-
Comparative Study of Influential Factors on Implementation of Energy Efficiency Measures in Single-Family Houses in Cold Climate
- 2018
-
Konferensbidrag (refereegranskat)abstract
- A combination of factors, which include occupants and building related aspects, could motivate homeowners to implement energy renovation (ER). This study applies a comparative approach to assess perspectives of single-family homeowners towards different energy efficiency measures (EEMs). The aim is to unveil the factors that are effective on the residents’ attitude and decision making to implement an EEM or a set of EEMs. The analysis is based on a questionnaire survey conducted during spring 2017 among1550 owners of single-family houses in seven municipalities in northern Sweden. Approximately, 35% of respondents expressed their interest to install energy efficient household appliances and solar photovoltaic (PV) systems. The analysis suggests significant relations between the homeowners’ interest to implement thermal envelope measures and the quality of the house such as age and indoor environmental problems such as cold surfaces. The group of respondents, who reported their heating cost to be high, are more likely to be interested in implementing thermal envelope measures than other measures such as HVAC. Several socio-economic factors are found to be significantly related with homeowners’ interest to implement EEMs.
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| 49. |
- Azizi, Shoaib, 1989-, et al.
(författare)
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Demand-controlled energy systems in commercial and institutional buildings : a review of methods and potentials
- 2019
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Ingår i: eceee 2019 Summer Study on energy efficiency. - : European Council for an Energy Efficient Economy (ECEEE). - 9789198387858 - 9789198387841 ; , s. 1444-1450
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Konferensbidrag (refereegranskat)abstract
- Heating, ventilation and air-conditioning (HVAC) are by farthe most energy intensive systems in commercial and institutionalbuildings with office spaces. This makes HVAC systemsattractive targets for energy efficiency improvement. New technologicaladvancements can play significant role on improvingenergy efficiency. Such advancements have been also emergedin form of novel management and control strategies, whichmight lead to considerable energy savings with relatively minorinvestments. This paper evaluates demand control HVAC andlighting to assess the energy saving potential of upgrading theconventional building energy systems.This paper provides a summary of different methods and occupancydetection technologies. A range of technologies andmethods are covered that vary in complexity, limitations andenergy saving potential. Additional benefits such as demandresponse are evaluated and other emerging applications arediscussed. Based on the review of methods and potentials, thepaper assesses the state of the art in demand controlled energysystems and suggests areas for further research.
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| 50. |
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