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| 2. |
- Alatalo, J. M., et al.
(författare)
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Bryophyte cover and richness decline after 18 years of experimental warming in alpine Sweden
- 2020
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Ingår i: Aob Plants. - Oxford : Oxford University Press (OUP). - 2041-2851. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, this study examined impacts of long-term warming on bryophyte communities. Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Species composition changed significantly from original communities in the heath, but remained similar in mesic meadow. Experimental warming increased beta diversity in the heath. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43 % to 11 % in heath and from 68 % to 35 % in meadow (75 % and 48 % decline, respectively, in original cover), while richness declined by 39 % and 26 %, respectively. Importantly, the decline in cover and richness first emerged after 7 years. Warming caused significant increase in litter in both plant communities. Deciduous shrub and litter cover had negative impact on bryophyte cover. We show that bryophyte species do not respond similarly to climate change. Total bryophyte cover declined in both heath and mesic meadow under experimental long-term warming (by 1.5-3 degrees C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath are more susceptible to warming than in meadow, supporting the suggestion that bryophytes may be less resistant in drier environments than in wetter habitats. Species loss was slower than the decline in bryophyte abundance, and diversity remained similar in both communities. Increased deciduous shrub and litter cover led to decline in bryophyte cover. The non-linear response to warming over time underlines the importance of long-term experiments and monitoring.
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| 3. |
- Chen, L., et al.
(författare)
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Numerical investigations of wind and thermal environment in 2D scaled street canyons with various aspect ratios and solar wall heating
- 2021
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Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 190
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Tidskriftsartikel (refereegranskat)abstract
- Optimizing urban ventilation is an effective way to improve urban air quality and thermal environment. For this purpose, under the validation of wind-tunnel experiments, flow regimes and micro thermal environment in typical reduced-canyon models with aspect ratios (AR) of 1.1, 2.4, 4 and 5.67 were investigated by CFD simulations using periodic boundary condition. ANSYS Fluent 15.0 with a solar ray tracing model and radiation model was performed to numerically study turbulence characteristics with wind-driven force and solar-heating conditions. Results revealed that, with wind-driven condition, a clockwise vortex existed in normal and deep street canyon (AR = 1.1 and 2.4) while two counter-rotating vortices appeared in extremely deep canyon (AR = 4 and 5.67). Moreover, different turbulence structures and air temperature distribution existed in canyons with different solar-heating conditions. When the leeward wall or ground was heated, the pedestrian-level velocity increased and street ventilation was strengthened compared to wind-driven condition for all AR values. Particularly, the single main vortex was strengthened (AR = 1.1 and 2.4), and the two-vortex structure in extremely deep canyons (AR = 4 and 5.67) changed to single-vortex structure. When the windward wall was heated, the clockwise main vortex at AR = 1.1 and 2.4 was deformed, and a new sub vortex gradually appeared near street bottom. Furthermore, at AR = 4 and 5.67, windward solar heating destroyed the two-vortex structure and slightly improved pollutant dilution capacity. This work implied that extremely deep street design with weak pedestrian-level ventilation should be avoided. It also provides a meaningful reference for urban planning.
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| 5. |
- Abd Nikooie Pour, Mina, et al.
(författare)
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Results of the Ontology Alignment Evaluation Initiative 2022
- 2022
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Ingår i: CEUR Workshop Proceedings. - : CEUR-WS. ; , s. 84-128, s. 84-128
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Konferensbidrag (refereegranskat)abstract
- The Ontology Alignment Evaluation Initiative (OAEI) aims at comparing ontology matching systems on precisely defined test cases. These test cases can be based on ontologies of different levels of complexity and use different evaluation modalities. The OAEI 2022 campaign offered 14 tracks and was attended by 18 participants. This paper is an overall presentation of that campaign. © 2022 Copyright for this paper by its authors.
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| 6. |
- Alatalo, J. M., et al.
(författare)
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Changes in plant composition and diversity in an alpine heath and meadow after 18 years of experimental warming
- 2022
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Ingår i: Alpine Botany. - Basel : Springer Science and Business Media LLC. - 1664-2201 .- 1664-221X. ; 132, s. 181-193
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Tidskriftsartikel (refereegranskat)abstract
- Global warming is expected to have large impacts on high alpine and Arctic ecosystems in the future. Here we report effects of 18 years of experimental warming on two contrasting high alpine plant communities in subarctic Sweden. Using open-top chambers, we analysed effects of long-term passive experimental warming on a heath and a meadow. We determined the impact on species composition, species diversity (at the level of rare, common and dominant species), and phylogenetic and functional diversity. Long-term warming drove differentiation in species composition in both communities; warmed plots, but not control plots, had distinctly different species composition in 2013 compared with 1995. Beta diversity increased in the meadow, while it decreased in the heath. Long-term warming had significant negative effects on the three orders of phylogenetic Hill diversity in the meadow. There was a similar tendency in the heath, but only phylogenetic diversity of dominant species was significantly affected. Long-term warming caused reductions in forbs in the heath, while evergreen shrubs increased. In the meadow, deciduous and evergreen shrubs showed increased abundance from 2001 to 2013 in warmed plots. Responses in species and phylogenetic diversity to experimental warming varied over both time (medium (7 years) vs long-term (18 years)) and space (between two neighbouring plant communities). The meadow community was more negatively affected in terms of species and phylogenetic diversity than the heath community. A potential driver for the changes in the meadow may be decreased soil moisture caused by long-term warming.
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| 7. |
- Alatalo, J. M., et al.
(författare)
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Responses of lichen communities to 18 years of natural and experimental warming
- 2017
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Ingår i: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 120:1, s. 159-170
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims Climate change is expected to have major impacts on high alpine and arctic ecosystems in the future, but empirical data on the impact of long-term warming on lichen diversity and richness are sparse. This study report the effects of 18 years of ambient and experimental warming on lichens and vascular plant cover in two alpine plant communities, a dry heath with sparse canopy cover (54 %) and a mesic meadow with a more developed (67 %) canopy cover, in sub-arctic Sweden. Methods The effects of long-term passive experimental warming using open top chambers (OTCs) on lichens and total vascular plant cover, and the impact of plant cover on lichen community parameters, were analysed. Key Results Between 1993 and 2013, mean annual temperature increased about 2 degrees C. Both site and experimental warming had a significant effect on cover, species richness, effective number of species evenness of lichens, and total plant canopy cover. Lichen cover increased in the heath under ambient conditions, and remained more stable under experimental warming. The negative effect on species richness and effective number of species was driven by a decrease in lichens under experimental warming in the meadow. Lichen cover, species richness, effective number of species evenness were negatively correlated with plant canopy cover. There was a significant negative impact on one species and a non-significant tendency of lower abundance of the most common species in response to experimental warming. Conclusions The results from the long-term warming study imply that arctic and high alpine lichen communities are likely to be negatively affected by climate change and an increase in plant canopy cover. Both biotic and abiotic factors are thus important for future impacts of climate change on lichens.
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| 8. |
- Chen, R., et al.
(författare)
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A low cost surface plasmon resonance biosensor using a laser line generator
- 2015
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 349, s. 83-88
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Tidskriftsartikel (refereegranskat)abstract
- Due to the instrument designed by using a common surface plasmon resonance biosensor is extremely expensive, we established a portable and cost-effective surface plasmon resonance biosensing system. It is mainly composed of laser line generator, P-polarizer, customized prism, microfluidic cell, and line Charge Coupled Device (CCD) array. Microprocessor PIC24FJ128GA006 with embedded A/D converter, communication interface circuit and photoelectric signal amplifier circuit are used to obtain the weak signals from the biosensing system. Moreover, the line CCD module is checked and optimized on the number of pixels, pixels dimension, output amplifier and the timing diagram. The micro-flow cell is made of stainless steel with a high thermal conductivity, and the microprocessor based Proportional-Integral-Derivative (PID) temperature-controlled algorithm was designed to keep the constant temperature (25 °C) of the sample solutions. Correspondingly, the data algorithms designed especially to this biosensing system including amplitude-limiting filtering algorithm, data normalization and curve plotting were programmed efficiently. To validate the performance of the biosensor, ethanol solution samples at the concentrations of 5%, 7.5%, 10%, 12.5% and 15% in volumetric fractions were used, respectively. The fitting equation ΔRU=-752987.265+570237.348×RI with the R-Square of 0.97344 was established by delta response units (ΔRUs) to refractive indexes (RI). The maximum relative standard deviation (RSD) of 4.8% was obtained.
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| 9. |
- Hu, J., et al.
(författare)
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Detection of clenbuterol hydrochloride residuals in pork liver using a customized surface plasmon resonance bioanalyzer
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- A surface plasmon resonance (SPR) immunoassay with an immobilization of self-assembled molecular identification membrane for the detection of residual Clenbuterol Hydrochloride (CLB) in pork liver was systematically investigated and experimentally validated for its high performance. SPR immunoassay with a regular competitive inhibition assay cannot be directly verified to detect CLB residuals. In this study, the binding of Au film with mercaptopropionic acid was investigated using the known form of the strong S-Au covalent bonds formed by the chemical radical of the mercaptopropionic acid and the Au film. After that, the immunoglobulin IgG of swine (SwIgG-CLB) was bonded with the mercaptopropionic acid by covalent -CO-NH- amide bonding. The modified comprehensive analysis of how the membrane structure works was introduced together with the customized SPR bioanalyzer. In order to evaluate the performance of this biomembrane structure, the concentrations of CLBcontained solutions of 0 ng•mL-1, 10 ng•mL-1, 20 ng•mL-1, 33.3 ng•mL-1, and 40 ng•mL-1 were prepared by adding CLB reagents into the solutions of CLB antibody (Clenbuterol Hydrochloride Antibody, CLB-Ab), successively and then the response unit (RU) was measured individually. Using the data collected from the linear CCD array, the fitting curve was established with the R-Square value of 0.9929. Correspondingly, the recovery rate ranged from 88.48% to 103.21% was experimented and the limit of detection of CLB in 1.26 ng•mL-1 was obtained efficiently. It was concluded that the detection method associated with biomembrane properties is expected to contribute much to the determination of residual CLB in pork liver quantitatively by using the customized SPR bioanalyzer. © 2015 Hu et al.
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| 10. |
- Samuelsson, Karl, Doktorand, et al.
(författare)
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Residential environments across Denmark have become both denser and greener over 20 years
- 2021
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Ingår i: Environmental Research Letters. - : IOP. - 1748-9326. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite much attention in the literature, knowledge about the dynamics surrounding urban densification and urban greening is still in dire need for architects, urban planners and scientists that strive to design, develop, and regenerate sustainable and resilient urban environments. Here, we investigate countrywide patterns of changes in residential density and residential nature at high spatial resolution over a time period of >20 years (1995-2016), combining a dataset of address-level population data covering all of Denmark (>2 million address points) with satellite image-derived Normalized Difference Vegetation Index (NDVI) data. Our results show that many residential environments across Denmark have witnessed simultaneous densification and greening since the mid-1990s. In fact, the most common change within 500 metre neighbourhoods around individual address points is of joint increases in population and NDVI (28%), followed by increasing NDVI with stable population figures (21%). In contrast, only 8% of neighbourhoods around address points have seen a decline in either population or NDVI. Results were similar in low- middle- and high-density environments, suggesting that trends were driven by climate change but also to some degree enabled by urban planning policies that seek to increase rather than decrease nature in the cities.
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