| 1. |
- Breznau, Nate, et al.
(författare)
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Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:44
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Tidskriftsartikel (refereegranskat)abstract
- This study explores how researchers analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each teams workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.
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| 2. |
- Mattsson, M., et al.
(författare)
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Personal factors in systemic sclerosis and their coverage by patient-reported outcome measures
- 2015
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Ingår i: European Journal of Physical and Rehabilitation Medicine. - 1827-1804. ; 51:4, s. 405-421
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Tidskriftsartikel (refereegranskat)abstract
- Background. Systemic sclerosis (SSc) is an autoimmune disease where thickening of the skin can lead to reduced body function and limitations in activities. Severe forms can also affect and seriously damage inner organs. Patient-centred rehabilitation emphasises considerations of patients' background, experience and behavior which highlights the need to know if patient-reported outcome measures (PROMs) include such personal factors. Aim. To identify and describe personal factors in the experiences of functioning and health of persons with SSc and to examine if and to what extent PROMs in SSc research cover these factors. Design. Data from a qualitative study with focus group interviews were analysed. PROMs in SSc research were identified in a literature review between 2008-2013. Setting. Participants were recruited from outpatient clinics at rheumatology department. Population. Sixty-three patients with SSc from four European countries participated. Methods. Data from interviews were analysed using a structure of personal factors developed by Geyh et al. Identified PROMs were analysed and linked to main concepts, related to the personal factors, found in the interview data. Results. Nineteen main concepts were related to the area "patterns of experience and behaviour" in the personal factor structure, 16 to "thoughts and beliefs", nine to "feelings", one to "motives" and one to "personal history and biography", respectively. Among the 35 PROMs identified, 15 did not cover any of the identified concepts. Concepts within the area "feelings" were mostly covered by the PROMs. Five of the PROMs covered "patterns of experience and behaviour", while "motives" and "personal history and biography" were not covered at all. Four of the identified PROMs covered concepts within the areas "feelings", "thoughts and beliefs" and "patterns of experience and behaviour" in the same instrument. The Illness Cognition Questionnaire and Illness Behaviour Questionnaire were such PROMs. Conclusion. Patterns of experience and behaviour had the highest number of concepts related to personal factors, but few of the PROMs in SSc research covered these factors. Only a few PROMs covered several personal factors areas in the same instrument. Clinical Rehabilitation Impact. The results would be of value when developing core sets for outcome measurements in SSc.
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| 3. |
- Namjou, Bahram, et al.
(författare)
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High-density genotyping of STAT4 reveals multiple haplotypic associations with systemic lupus erythematosus in different racial groups
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:4, s. 1085-1095
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Systemic lupus erythematosus (SLE) is the prototypical systemic autoimmune disorder, with complex etiology and a strong genetic component. Recently, gene products involved in the interferon pathway have been under intense investigation in terms of the pathogenesis of SLE. STAT-1 and STAT-4 are transcription factors that play key roles in the interferon and Th1 signaling pathways, making them attractive candidates for involvement in SLE susceptibility. METHODS: Fifty-six single-nucleotide polymorphisms (SNPs) across STAT1 and STAT4 on chromosome 2 were genotyped using the Illumina platform, as part of an extensive association study in a large collection of 9,923 lupus patients and control subjects from different racial groups. DNA samples were obtained from the peripheral blood of patients with SLE and control subjects. Principal components analyses and population-based case-control association analyses were performed, and the P values, false discovery rate q values, and odds ratios with 95% confidence intervals were calculated. RESULTS: We observed strong genetic associations with SLE and multiple SNPs located within STAT4 in different ethnic groups (Fisher's combined P = 7.02 x 10(-25)). In addition to strongly confirming the previously reported association in the third intronic region of this gene, we identified additional haplotypic association across STAT4 and, in particular, a common risk haplotype that is found in multiple racial groups. In contrast, only a relatively weak suggestive association was observed with STAT1, probably due to its proximity to STAT4. CONCLUSION: Our findings indicate that STAT4 is likely to be a crucial component in SLE pathogenesis in multiple racial groups. Knowledge of the functional effects of this association, when they are revealed, might improve our understanding of the disease and provide new therapeutic targets.
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| 4. |
- Nilsson, Peter M, et al.
(författare)
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Heart failure and metabolic factors
- 2019
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Ingår i: Hypertension and Heart Failure : Epidemiology, Mechanisms and Treatment - Epidemiology, Mechanisms and Treatment. - 9783319933191 - 9783319933207 ; , s. 123-133
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Bokkapitel (refereegranskat)
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| 5. |
- Arechvo, Anastasjja, et al.
(författare)
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Maternal race and pre-eclampsia : Cohort study and systematic review with meta-analysis
- 2022
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Ingår i: BJOG: An International Journal of Obstetrics and Gynaecology. - : Wiley. - 1470-0328 .- 1471-0528. ; 129:12, s. 2082-2093
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To examine the association between race and pre-eclampsia and gestational hypertension after adjustment for factors in maternal characteristics and medical history in a screening study from the Fetal Medicine Foundation (FMF) in England, and to perform a systematic review and meta-analysis of studies on pre-eclampsia. Design: Prospective observational study and systematic review with meta-analysis. Setting: Two UK maternity hospitals. Population: A total of 168 966 women with singleton pregnancies attending for routine ultrasound examination at 11–13 weeks of gestation without major abnormalities delivering at 24 weeks or more of gestation. Methods: Regression analysis examined the association between race and pre-eclampsia or gestational hypertension in the FMF data. Literature search to December 2021 was carried out to identify peer-reviewed publications on race and pre-eclampsia. Main outcome measure: Relative risk of pre-eclampsia and gestational hypertension in women of black, South Asian and East Asian race by comparison to white women. Results: In black women, the respective risks of total-pre-eclampsia and preterm-pre-eclampsia were 2-fold and 2.5-fold higher, respectively, and risk of gestational hypertension was 25% higher; in South Asian women there was a 1.5-fold higher risk of preterm pre-eclampsia but not of total-pre-eclampsia and in East Asian women there was no statistically significant difference in risk of hypertensive disorders. The literature search identified 19 studies that provided data on several million pregnancies, but 17 were at moderate or high-risk of bias and only three provided risks adjusted for some maternal characteristics; consequently, these studies did not provide accurate contributions on different racial groups to the prediction of pre-eclampsia. Conclusion: In women of black and South Asian origin the risk of pre-eclampsia, after adjustment for confounders, is higher than in white women.
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| 6. |
- Morjan, I., et al.
(författare)
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Carbon nanotubes growth from C2H2 and C2H4/NH3 by catalytic LCVD on supported iron-carbon nanocomposites
- 2007
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Ingår i: Physica E: Low-Dimensional Systems and Nanostructures. - : Elsevier BV. - 1386-9477. ; 37:1-2, s. 26-33
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Tidskriftsartikel (refereegranskat)abstract
- We report about the synthesis of carbon nanotubes by catalytic LCVD (C-LCVD), using a CW CO2 laser and alternatively, C2H2/ C2H4/NH3 and C2H2/C2H4-containing gas mixtures. Different core-shell Fe-C nanocomposites (as synthesized and toluene extracted) were used employed as catalysts. The nanotubes grown from Fe-C residue demonstrate the lowest mean diameters. Prevalent curled and coiled morphologies are obtained for the CNTs grown in the presence of ammonia. (c) 2006 Elsevier B.V. All rights reserved.
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| 7. |
- Nilsson, Peter M, et al.
(författare)
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New Antidiabetic Agents for the Treatment of Heart Failure in Hypertensive Patients
- 2024. - 2
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Ingår i: Hypertension and Heart Failure : Epidemiology, Mechanisms and Treatment - Epidemiology, Mechanisms and Treatment. - 2366-4614 .- 2366-4606. - 9783031393143 - 9783031393150 ; , s. 79-371
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Bokkapitel (refereegranskat)abstract
- The development of newer glucose-lowering drugs for the treatment of type 2 diabetes in recent years, such as the SGLT-2 inhibitors and GLP-1 receptor agonists/analogues with well-documented clinical benefits from large trials, has influenced international guidelines. These drugs are able to reduce both macro- and microvascular events in patients with type 2 diabetes and to prevent worsening of diabetic nephropathy. One important aspect of these new drugs is also the ability to prevent or treat heart failure (HF) through improved cardiac metabolism, but also by lowering of blood pressure and improvement of central hemodynamics. In this review, the evidence for such effects on HF is discussed for each drug class separately and in combination. In the future there may come new opportunities for fixed drug combinations (FDC) to improve cost-effectiveness and compliance of diabetes treatment when antihypertensive, lipid-lowering, and glucose-lowering drugs are combined. As control of hypertension is of great importance for HF prevention in patients with diabetes in general, the combination of traditional antihypertensive drugs (i.e., blockers of the renin-angiotensin system) with newer glucose-lowering drugs that may also lower blood pressure could prove to be a successful and a very useful combination. Thus, further studies are warranted.
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| 8. |
- Voicu, A. M., et al.
(författare)
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Measurement Study of Dense Networks with Heterogeneous IEEE 802.11ac Wi-Fi Devices
- 2021
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Ingår i: 2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021 - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Wi-Fi devices are being increasingly deployed for both traditional high-throughput and new IoT applications. Thus, highly heterogeneous Wi-Fi devices with different configurations and capabilities will be co-located in dense deployments. However, it is not yet fully understood how such devices share the spectrum among each other and what performance they achieve, especially in dense emerging deployments. This paper presents extensive throughput measurements from a dense indoor IEEE 802.11ac testbed with heterogeneous commercial devices. Some links use high-throughput Asus devices with sophisticated MIMO configurations and others use single-antenna Raspberry Pis (RPis), as simpler IoT devices. Moreover, these links are configured to operate on different co- and adjacent channels of different widths. We show that there is a non-trivial interplay between PHY capabilities and contention at the MAC layer, with unintended consequences. Namely, adjacent channel interference (ACI) causes asymmetric channel contention where only Asus devices defer transmissions, whereas RPis do not, likely due to their different receiver filters. Two major consequences are: (i) in heterogeneous deployments the Asus links often have a throughput that is tens of Mbps lower than that of the RPi links, despite the more sophisticated MIMO capabilities of the Asus devices; and (ii) contention due to ACI among devices operating on narrow channels affects contention also with devices operating on wide overlapping channels and determines whether the latter starve or not. Our results suggest overall that better knowledge of the unintentional effects due to PHY-MAC interactions is needed, in order to explicitly take this into account when designing fair and predictable spectrum sharing mechanisms.
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| 9. |
- Voicu, A. M., et al.
(författare)
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Modelling broadband wireless technology coexistence in the unlicensed bands
- 2021
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Ingår i: Proceedings - 2021 IEEE 22nd International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2021. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 129-138
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Konferensbidrag (refereegranskat)abstract
- Increasingly more unlicensed bands accommodate multiple broadband technologies, e.g. Wi-Fi and LTE in the 5 GHz band and Wi-Fi 6E and 5G NR-U in the new 6 GHz unlicensed band. In these bands, the technologies coexist primarily via distributed MAC spectrum sharing mechanisms, so it is crucial to evaluate their performance using the right tools that reliably and accurately model the coexisting schemes. CSMA and duty cycle are representative schemes in this context, but the few modelling tools that capture their coexistence performance are yet to be properly evaluated in terms of accuracy and computational efficiency. This paper is the first to compare three such modelling tools - stochastic geometry modelling (SGM), ns-3, and our hybrid model - which comprise different time granularities and abstraction levels for the MAC mechanisms. We compare both the accuracy of their estimated SINR and throughput versus ns-3 and their computational efficiency, for CSMA and duty cycle coexistence. Furthermore, we make recommendations pertinent to future broadband coexistence cases. Our results show that ns-3 captures important effects of the CSMA sensing time on the SINR, but its computation time may be prohibitive for modelling coexisting dense networks. This tool is thus useful primarily for studying dynamic MAC features in small to medium-sized coexisting deployments. SGM is the least accurate and also requires a long computation time, so we argue it is the least attractive approach to model coexisting CSMA and duty cycle technologies. Finally, our hybrid model yields the time-average per-link SINR with reasonable accuracy and the throughput with good accuracy and is at least two orders of magnitude faster to compute than SGM and ns-3, making it very well suited for extensive Monte Carlo simulations and large networks.
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| 10. |
- Voicu, Andra M., et al.
(författare)
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Modelling Large-Scale CSMA Wireless Networks
- 2021
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Ingår i: 2021 IEEE Wireless Communications and Networking Conference (WCNC). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Increasingly more wireless devices adopt CSMA at the MAC layer, primarily due to the ubiquitous utilization of Wi-Fi, but also due to the development of new standards that implement CSMA variants, like LAA-LTE. It is thus critical to use reliable modelling tools that accurately evaluate the performance of large-scale CSMA deployments, as expected in practice. This paper compares the accuracy and computational efficiency of stochastic geometry modelling (SGM) and our proposed hybrid model, for estimating the MAC-layer throughput and signal-to-interference-and-noise ratio (SINR) of large-scale CSMA wireless deployments. Using ns-3 simulations as the baseline reference, we show that our hybrid model is significantly more accurate and at least one order of magnitude faster to compute than SGM. SGM underestimates the SINR, yet as it neglects the sensing overhead, it usually overestimates the MAC-layer throughput substantially. We thus argue that our hybrid model is preferable to SGM for modelling large-scale CSMA deployments.
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