| 1071. |
- Lu, Ru-Sen, et al.
(författare)
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Detection of Intrinsic Source Structure at similar to 3 Schwarzschild Radii with Millimeter-VLBI Observations of SAGITTARIUS A*
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 859:1
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Tidskriftsartikel (refereegranskat)abstract
- We report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in 2013 March using six VLBI stations in Hawaii, California, Arizona, and Chile. Compared to earlier observations, the addition of the APEX telescope in Chile almost doubles the longest baseline length in the array, provides additional uv coverage in the N-S direction, and leads to a spatial resolution of similar to 30 mu as (similar to 3 Schwarzschild radii) for Sgr A*. The source is detected even at the longest baselines with visibility amplitudes of similar to 4%-13% of the total flux density. We argue that such flux densities cannot result from interstellar refractive scattering alone, but indicate the presence of compact intrinsic source structure on scales of similar to 3 Schwarzschild radii. The measured nonzero closure phases rule out point-symmetric emission. We discuss our results in the context of simple geometric models that capture the basic characteristics and brightness distributions of disk-and jet-dominated models and show that both can reproduce the observed data. Common to these models are the brightness asymmetry, the orientation, and characteristic sizes, which are comparable to the expected size of the black hole shadow. Future 1.3 mm VLBI observations with an expanded array and better sensitivity will allow more detailed imaging of the horizon-scale structure and bear the potential for a deep insight into the physical processes at the black hole boundary.
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| 1072. |
- Magee, M. R., et al.
(författare)
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The type Iax supernova, SN 2015H A white dwarf deflagration candidate
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 589
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Tidskriftsartikel (refereegranskat)abstract
- We present results based on observations of SN 2015H which belongs to the small group of objects similar to SN 2002cx, otherwise known as type Iax supernovae. The availability of deep pre-explosion imaging allowed us to place tight constraints on the explosion epoch. Our observational campaign began approximately one day post-explosion, and extended over a period of about 150 days post maximum light, making it one of the best observed objects of this class to date. We find a peak magnitude of M-r = 17.27 +/- 0.07, and a (Delta m(15))(r) = 0.69 +/- 0.04. Comparing our observations to synthetic spectra generated from simulations of deflagrations of Chandrasekhar mass carbon-oxygen white dwarfs, we find reasonable agreement with models of weak deflagrations that result in the ejection of similar to 0.2 M-circle dot of material containing similar to 0.07 M-circle dot of Ni-56. The model light curve however, evolves more rapidly than observations, suggesting that a higher ejecta mass is to be favoured. Nevertheless, empirical modelling of the pseudo-bolometric light curve suggests that less than or similar to 0.6 M-circle dot of material was ejected, implying that the white dwarf is not completely disrupted, and that a bound remnant is a likely outcome.
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| 1073. |
- Mandt, Kathleen E., et al.
(författare)
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Ion densities and composition of Titan's upper atmosphere derived from the Cassini Ion Neutral Mass Spectrometer : Analysis methods and comparison of measured ion densities to photochemical model simulations
- 2012
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 117, s. E10006-
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Tidskriftsartikel (refereegranskat)abstract
- The Cassini Ion Neutral Mass Spectrometer (INMS) has measured both neutral and ion species in Titan's upper atmosphere and ionosphere and the Enceladus plumes. Ion densities derived from INMS measurements are essential data for constraining photochemical models of Titan's ionosphere. The objective of this paper is to present an optimized method for converting raw data measured by INMS to ion densities. To do this, we conduct a detailed analysis of ground and in-flight calibration to constrain the instrument response to ion energy, the critical parameter on which the calibration is based. Data taken by the Cassini Radio Plasma Wave Science Langmuir Probe and the Cassini Plasma Spectrometer Ion Beam Spectrometer are used as independent measurement constraints in this analysis. Total ion densities derived with this method show good agreement with these data sets in the altitude region (similar to 1100-1400 km) where ion drift velocities are low and the mass of the ions is within the measurement range of the INMS (1-99 Daltons). Although ion densities calculated by the method presented here differ slightly from those presented in previous INMS publications, we find that the implications for the science presented in previous publications is mostly negligible. We demonstrate the role of the INMS ion densities in constraining photochemical models and find that (1) cross sections having high resolution as a function of wavelength are necessary for calculating the initial photoionization products and (2) there are disagreements between the measured ion densities representative of the initial steps in Titan photochemistry that require further investigation.
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| 1074. |
- McBrien, Owen R., et al.
(författare)
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SN2018kzr : A Rapidly Declining Transient from the Destruction of a White Dwarf
- 2019
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 885:1
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Tidskriftsartikel (refereegranskat)abstract
- We present SN2018kzr, the fastest declining supernova-like transient, second only to the kilonova, AT2017gfo. SN2018kzr is characterized by a peak magnitude of M-r & xfffd;=& xfffd;?17.98, a peak bolometric luminosity of ?1.4 & xfffd;& x5e0;10(43) erg s(?1), and a rapid decline rate of 0.48 & xfffd;& xfffd;0.03 mag day(?1) in the r band. The bolometric luminosity evolves too quickly to be explained by pure Ni-56 heating, necessitating the inclusion of an alternative powering source. Incorporating the spin-down of a magnetized neutron star adequately describes the lightcurve and we estimate a small ejecta mass of M-ej & xfffd;=& xfffd;0.10 & xfffd;& xfffd;0.05 M. Our spectral modeling suggests the ejecta is composed of intermediate mass elements including O, Si, and Mg and trace amounts of Fe-peak elements, which disfavors a binary neutron star merger. We discuss three explosion scenarios for SN2018kzr, given the low ejecta mass, intermediate mass element composition, and high likelihood of additional powering?the core collapse of an ultra-stripped progenitor, the accretion induced collapse (AIC) of a white dwarf, and the merger of a white dwarf and neutron star. The requirement for an alternative input energy source favors either the AIC with magnetar powering or a white dwarf?neutron star merger with energy from disk wind shocks.
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| 1075. |
- McCarroll, D., et al.
(författare)
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A 1200-year multiproxy record of tree growth and summer temperature at the northern pine forest limit of Europe
- 2013
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Ingår i: Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 23:4, s. 471-484
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Tidskriftsartikel (refereegranskat)abstract
- Combining nine tree growth proxies from four sites, from the west coast of Norway to the Kola Peninsula of NW Russia, provides a well replicated (> 100 annual measurements per year) mean index of tree growth over the last 1200 years that represents the growth of much of the northern pine timberline forests of northern Fennoscandia. The simple mean of the nine series, z-scored over their common period, correlates strongly with mean June to August temperature averaged over this region (r = 0.81), allowing reconstructions of summer temperature based on regression and variance scaling. The reconstructions correlate significantly with gridded summer temperatures across the whole of Fennoscandia, extending north across Svalbard and south into Denmark. Uncertainty in the reconstructions is estimated by combining the uncertainty in mean tree growth with the uncertainty in the regression models. Over the last seven centuries the uncertainty is < 4.5% higher than in the 20th century, and reaches a maximum of 12% above recent levels during the 10th century. The results suggest that the 20th century was the warmest of the last 1200 years, but that it was not significantly different from the 11th century. The coldest century was the 17th. The impact of volcanic eruptions is clear, and a delayed recovery from pairs or multiple eruptions suggests the presence of some positive feedback mechanism. There is no clear and consistent link between northern Fennoscandian summer temperatures and solar forcing.
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| 1076. |
- McKeown, Nicola M., et al.
(författare)
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Sugar-sweetened beverage intake associations with fasting glucose and insulin concentrations are not modified by selected genetic variants in a ChREBP-FGF21 pathway : a meta-analysis
- 2018
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 61:2, s. 317-330
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis: Sugar-sweetened beverages (SSBs) are a major dietary contributor to fructose intake. A molecular pathway involving the carbohydrate responsive element-binding protein (ChREBP) and the metabolic hormone fibroblast growth factor 21 (FGF21) may influence sugar metabolism and, thereby, contribute to fructose-induced metabolic disease. We hypothesise that common variants in 11 genes involved in fructose metabolism and the ChREBP-FGF21 pathway may interact with SSB intake to exacerbate positive associations between higher SSB intake and glycaemic traits. Methods: Data from 11 cohorts (six discovery and five replication) in the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium provided association and interaction results from 34,748 adults of European descent. SSB intake (soft drinks, fruit punches, lemonades or other fruit drinks) was derived from food-frequency questionnaires and food diaries. In fixed-effects meta-analyses, we quantified: (1) the associations between SSBs and glycaemic traits (fasting glucose and fasting insulin); and (2) the interactions between SSBs and 18 independent SNPs related to the ChREBP-FGF21 pathway. Results: In our combined meta-analyses of discovery and replication cohorts, after adjustment for age, sex, energy intake, BMI and other dietary covariates, each additional serving of SSB intake was associated with higher fasting glucose (β ± SE 0.014 ± 0.004 [mmol/l], p = 1.5 × 10−3) and higher fasting insulin (0.030 ± 0.005 [loge pmol/l], p = 2.0 × 10−10). No significant interactions on glycaemic traits were observed between SSB intake and selected SNPs. While a suggestive interaction was observed in the discovery cohorts with a SNP (rs1542423) in the β-Klotho (KLB) locus on fasting insulin (0.030 ± 0.011 loge pmol/l, uncorrected p = 0.006), results in the replication cohorts and combined meta-analyses were non-significant. Conclusions/interpretation: In this large meta-analysis, we observed that SSB intake was associated with higher fasting glucose and insulin. Although a suggestive interaction with a genetic variant in the ChREBP-FGF21 pathway was observed in the discovery cohorts, this observation was not confirmed in the replication analysis. Trial registration: Trials related to this study were registered at clinicaltrials.govas NCT00005131 (Atherosclerosis Risk in Communities), NCT00005133 (Cardiovascular Health Study), NCT00005121 (Framingham Offspring Study), NCT00005487 (Multi-Ethnic Study of Atherosclerosis) and NCT00005152 (Nurses’ Health Study).
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| 1077. |
- Moore, Keith J M, et al.
(författare)
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Loop-Mediated Isothermal Amplification Detection of SARS-CoV-2 and Myriad Other Applications
- 2021
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Ingår i: Journal of Biomolecular Techniques. - : Association of Biomolecular Resource Facilities. - 1524-0215 .- 1943-4731. ; 32:3, s. 228-275
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Forskningsöversikt (refereegranskat)abstract
- As the second year of the COVID-19 pandemic begins, it remains clear that a massive increase in the ability to test for SARS-CoV-2 infections in a myriad of settings is critical to controlling the pandemic and to preparing for future outbreaks. The current gold standard for molecular diagnostics is the polymerase chain reaction (PCR), but the extraordinary and unmet demand for testing in a variety of environments means that both complementary and supplementary testing solutions are still needed. This review highlights the role that loop-mediated isothermal amplification (LAMP) has had in filling this global testing need, providing a faster and easier means of testing, and what it can do for future applications, pathogens, and the preparation for future outbreaks. This review describes the current state of the art for research of LAMP-based SARS-CoV-2 testing, as well as its implications for other pathogens and testing. The authors represent the global LAMP (gLAMP) Consortium, an international research collective, which has regularly met to share their experiences on LAMP deployment and best practices; sections are devoted to all aspects of LAMP testing, including preanalytic sample processing, target amplification, and amplicon detection, then the hardware and software required for deployment are discussed, and finally, a summary of the current regulatory landscape is provided. Included as well are a series of first-person accounts of LAMP method development and deployment. The final discussion section provides the reader with a distillation of the most validated testing methods and their paths to implementation. This review also aims to provide practical information and insight for a range of audiences: for a research audience, to help accelerate research through sharing of best practices; for an implementation audience, to help get testing up and running quickly; and for a public health, clinical, and policy audience, to help convey the breadth of the effect that LAMP methods have to offer.
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| 1078. |
- Ozgen, H, et al.
(författare)
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International Consensus Statement for the Screening, Diagnosis, and Treatment of Adolescents with Concurrent Attention-Deficit/Hyperactivity Disorder and Substance Use Disorder
- 2020
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Ingår i: European addiction research. - : S. Karger AG. - 1421-9891 .- 1022-6877. ; 26:4-5, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Childhood attention-deficit/hyperactivity disorder (ADHD) is a risk factor for substance misuse and substance use disorder (SUD) in adolescence and (early) adulthood. ADHD and SUD also frequently co-occur in treatment-seeking adolescents, which complicates diagnosis and treatment and is associated with poor treatment outcomes. Research on the effect of treatment of childhood ADHD on the prevention of adolescent SUD is inconclusive, and studies on the diagnosis and treatment of adolescents with ADHD and SUD are scarce. Thus, the available evidence is generally not sufficient to justify robust treatment recommendations. <b><i>Objective:</i></b> The aim of the study was to obtain a consensus statement based on a combination of scientific data and clinical experience. <b><i>Method:</i></b> A modified Delphi study to reach consensus based upon the combination of scientific data and clinical experience with a multidisciplinary group of 55 experts from 17 countries. The experts were asked to rate a set of statements on the effect of treatment of childhood ADHD on adolescent SUD and on the screening, diagnosis, and treatment of adolescents with comorbid ADHD and SUD. <b><i>Results:</i></b> After 3 iterative rounds of rating and adapting 37 statements, consensus was reached on 36 of these statements representing 6 domains: general (<i>n</i> = 4), risk of developing SUD (<i>n</i> = 3), screening and diagnosis (<i>n</i> = 7), psychosocial treatment (<i>n</i> = 5), pharmacological treatment (<i>n</i> = 11), and complementary treatments (<i>n</i> = 7). Routine screening is recommended for ADHD in adolescent patients in substance abuse treatment and for SUD in adolescent patients with ADHD in mental healthcare settings. Long-acting stimulants are recommended as the first-line treatment of ADHD in adolescents with concurrent ADHD and SUD, and pharmacotherapy should preferably be embedded in psychosocial treatment. The only remaining no-consensus statement concerned the requirement of abstinence before starting pharmacological treatment in adolescents with ADHD and concurrent SUD. In contrast to the majority, some experts required full abstinence before starting any pharmacological treatment, some were against the use of stimulants in the treatment of these patients (independent of abstinence), while some were against the alternative use of bupropion. <b><i>Conclusion:</i></b> This international consensus statement can be used by clinicians and patients together in a shared decision-making process to select the best interventions and to reach optimal outcomes in adolescent patients with concurrent ADHD and SUD.
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| 1079. |
- Ozgen, H, et al.
(författare)
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[International Consensus Statement for the Screening, Diagnosis, and Treatment of Adolescents with Concurrent Attention-Deficit/Hyperactivity Disorder and Substance Use Disorder]
- 2022
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Ingår i: Zeitschrift fur Kinder- und Jugendpsychiatrie und Psychotherapie. - : Hogrefe Publishing Group. - 1422-4917 .- 1664-2880. ; 50:1, s. 54-67
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Tidskriftsartikel (refereegranskat)abstract
- Zusammenfassung. Hintergrund: Eine Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) im Kindesalter stellt einen Risikofaktor für Substanzmissbrauch und Störungen durch Substanzgebrauch (Substance Use Disorder, SUD) in der Pubertät und dem (frühen) Erwachsenenalter dar. ADHS und SUD treten auch häufig bei therapiesuchenden Jugendlichen auf, was die Diagnosestellung und Therapie erschwert sowie mit schlechten Behandlungsergebnissen verbunden ist. Forschungsergebnisse über die Wirkung der Behandlung von ADHS im Kindesalter auf die Prävention von SUD im Jugendalter sind nicht eindeutig und Studien über die Diagnose und Behandlung von Jugendlichen mit ADHS und SUD sind selten. Daher reicht die verfügbare Evidenz allgemein nicht aus, um starke Behandlungsempfehlungen zu rechtfertigen. Fragestellung: Ziel dieser Arbeit war es, eine Konsenserklärung auf der Grundlage von wissenschaftlichen Daten und klinischen Erfahrungen zu erhalten. Methodik: Es wurde eine modifizierte Delphi-Studie durchgeführt, um basierend auf der Kombination von wissenschaftlichen Daten und klinischer Erfahrung mit einer multidisziplinären Gruppe von 55 Expert_innen aus 17 Ländern einen Konsens zu erzielen. Die Expert_innen wurden gebeten, eine Reihe von Aussagen über die Wirkung der Behandlung von ADHS im Kindesalter auf die SUD bei Jugendlichen sowie über das Screening, die Diagnostik und die Behandlung von Jugendlichen mit komorbidem ADHS und SUD zu bewerten. Ergebnisse: Nach drei iterativen Bewertungsrunden und der Anpassung von 37 Aussagen wurde ein Konsens über 36 dieser Aussagen erzielt, die sechs Bereiche repräsentieren: allgemein ( n = 4), Risiko der Entwicklung einer SUD ( n = 3), Screening und Diagnostik ( n = 7), psychosoziale Behandlung ( n = 5), pharmakologische Behandlung ( n = 11) und komplementäre Behandlungen ( n = 7). Der Einsatz von Routinescreenings auf ADHS wird bei adoleszenten Patient_innen in einer Suchtbehandlung ebenso wie Routinescreenings auf SUD bei jugendlichen Patient_innen mit ADHS in allgemeinpsychiatrischen Therapiesettings empfohlen. Langwirksame Stimulanzien werden als Behandlung der ersten Wahl von ADHS bei Jugendlichen mit gleichzeitiger ADHS und SUD empfohlen. Die Pharmakotherapie sollte vorzugsweise in psychosoziale Behandlung eingebettet werden. Die einzige nichtkonsentierte Aussage betraf die Notwendigkeit von Abstinenz vor Beginn einer pharmakologischen Behandlung bei Jugendlichen mit ADHS und gleichzeitigem SUD. Im Gegensatz zur Mehrheit verlangten einige Expert_innen eine vollständige Abstinenz vor Beginn einer pharmakologischen Behandlung, einige waren gegen die Verwendung von Stimulanzien bei der Behandlung dieser Patient_innen (unabhängig von Abstinenz), während einige sich gegen die alternative Anwendung von Bupropion aussprachen. Schlussfolgerungen: Diese internationale Konsenserklärung kann von Kliniker_innen und Patient_innen zusammen in einem gemeinsamen Entscheidungsprozess genutzt werden, um die besten Interventionen auszuwählen und die bestmöglichen Ergebnisse bei adoleszenten Patient_innen mit gleichzeitiger ADHS und SUD zu erzielen.
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| 1080. |
- Parsa, Afshin, et al.
(författare)
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Common Variants in Mendelian Kidney Disease Genes and Their Association with Renal Function
- 2013
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 24:12, s. 2105-2117
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Tidskriftsartikel (refereegranskat)abstract
- Many common genetic variants identified by genome-wide association studies for complex traits map to genes previously linked to rare inherited Mendelian disorders. A systematic analysis of common single-nucleotide polymorphisms (SNPs) in genes responsible for Mendelian diseases with kidney phenotypes has not been performed. We thus developed a comprehensive database of genes for Mendelian kidney conditions and evaluated the association between common genetic variants within these genes and kidney function in the general population. Using the Online Mendelian Inheritance in Man database, we identified 731 unique disease entries related to specific renal search terms and confirmed a kidney phenotype in 218 of these entries, corresponding to mutations in 258 genes. We interrogated common SNPs (minor allele frequency >5%) within these genes for association with the estimated GFR in 74,354 European-ancestry participants from the CKDGen Consortium. However, the top four candidate SNPs (rs6433115 at LRP2, rs1050700 at TSC1, rs249942 at PALB2, and rs9827843 at ROBO2) did not achieve significance in a stage 2 meta-analysis performed in 56,246 additional independent individuals, indicating that these common SNPs are not associated with estimated GFR. The effect of less common or rare variants in these genes on kidney function in the general population and disease-specific cohorts requires further research.
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