370 research outputs found
Dissipative Waves in Fluids Having Both Positive and Negative Nonlinearity
The present study examines weakly dissipative, weakly nonlinear waves in which the fundamental derivative changes sign. The undisturbed state is taken to be at rest, uniform and in the vicinity of the 0 locus. The cubic Burgers equation governing these waves is solved numerically; the resultant solutions are compared and contrasted to those of the invisced theory. Further results include the presentation of a natural scaling law and inviscid solutions not reported elsewhere
Traditional and Health-Related Philanthropy: The Role of Resources and Personality
I study the relationships of resources and personality characteristics to charitable giving, postmortem organ donation, and blood donation in a nationwide sample of persons in households in the Netherlands. I find that specific personality characteristics are related to specific types of giving: agreeableness to blood donation, empathic concern to charitable giving, and prosocial value orientation to postmortem organ donation. I find that giving has a consistently stronger relation to human and social capital than to personality. Human capital increases giving; social capital increases giving only when it is approved by others. Effects of prosocial personality characteristics decline at higher levels of these characteristics. Effects of empathic concern, helpfulness, and social value orientations on generosity are mediated by verbal proficiency and church attendance.
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Coastal Resident Knowledge of New Marine Reserves in Oregon: The Impact of Proximity and Attachment
This article examines resident proximity and attachment to a new system of marine reserves in Oregon (USA), and the extent that these factors are related to both self-assessed and factual knowledge about these reserves. Data were from a survey of residents along the Oregon coast (n = 596). Residents reported higher self-assessed than factual knowledge about these reserves, which was low with 65% answering half or fewer of 16 factual questions correctly. Self-assessed and factual knowledge did not differ between communities proximate to (i.e., communities of place within 10 miles of these reserves) and more distant from these reserves (i.e., rest of coast). Factual knowledge also did not differ based on attachment to these areas, but place attachment was slightly related to aspects of self-assessed knowledge where those with higher attachment believed they were somewhat more knowledgeable about these reserves. Implications of these results for management and research are discussed.Keywords: proximity, knowledge, marine protected areas, residents, place attachment, marine reserve
Characteristics associated with quality of life among people with drug-resistant epilepsy
Quality of Life (QoL) is the preferred outcome in non-pharmacological trials, but there is little UK population evidence of QoL in epilepsy. In advance of evaluating an epilepsy self-management course we aimed to describe, among UK participants, what clinical and psycho-social characteristics are associated with QoL. We recruited 404 adults attending specialist clinics, with at least two seizures in the prior year and measured their self-reported seizure frequency, co-morbidity, psychological distress, social characteristics, including self-mastery and stigma, and epilepsy-specific QoL (QOLIE-31-P). Mean age was 42 years, 54% were female, and 75% white. Median time since diagnosis was 18 years, and 69% experienced â„10 seizures in the prior year. Nearly half (46%) reported additional medical or psychiatric conditions, 54% reported current anxiety and 28% reported current depression symptoms at borderline or case level, with 63% reporting felt stigma. While a maximum QOLIE-31-P score is 100, participantsâ mean score was 66, with a wide range (25â99). In order of large to small magnitude: depression, low self-mastery, anxiety, felt stigma, a history of medical and psychiatric comorbidity, low self-reported medication adherence, and greater seizure frequency were associated with low QOLIE-31-P scores. Despite specialist care, UK people with epilepsy and persistent seizures experience low QoL. If QoL is the main outcome in epilepsy trials, developing and evaluating ways to reduce psychological and social disadvantage are likely to be of primary importance. Educational courses may not change QoL, but be one component supporting self-management for people with long-term conditions, like epilepsy
Experimental Quantum Hamiltonian Learning
Efficiently characterising quantum systems, verifying operations of quantum
devices and validating underpinning physical models, are central challenges for
the development of quantum technologies and for our continued understanding of
foundational physics. Machine-learning enhanced by quantum simulators has been
proposed as a route to improve the computational cost of performing these
studies. Here we interface two different quantum systems through a classical
channel - a silicon-photonics quantum simulator and an electron spin in a
diamond nitrogen-vacancy centre - and use the former to learn the latter's
Hamiltonian via Bayesian inference. We learn the salient Hamiltonian parameter
with an uncertainty of approximately . Furthermore, an observed
saturation in the learning algorithm suggests deficiencies in the underlying
Hamiltonian model, which we exploit to further improve the model itself. We go
on to implement an interactive version of the protocol and experimentally show
its ability to characterise the operation of the quantum photonic device. This
work demonstrates powerful new quantum-enhanced techniques for investigating
foundational physical models and characterising quantum technologies
The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brainâbehavior relationships after stroke
The goal of the Enhancing Neuroimaging Genetics through MetaâAnalysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using wellâpowered metaâ and megaâanalytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and largeâscale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided
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Protein-coding variants implicate novel genes related to lipid homeostasis contributing to body-fat distribution.
Body-fat distribution is a risk factor for adverse cardiovascular health consequences. We analyzed the association of body-fat distribution, assessed by waist-to-hip ratio adjusted for body mass index, with 228,985 predicted coding and splice site variants available on exome arrays in up to 344,369 individuals from five major ancestries (discovery) and 132,177 European-ancestry individuals (validation). We identified 15 common (minor allele frequency, MAF â„5%) and nine low-frequency or rare (MAF <5%) coding novel variants. Pathway/gene set enrichment analyses identified lipid particle, adiponectin, abnormal white adipose tissue physiology and bone development and morphology as important contributors to fat distribution, while cross-trait associations highlight cardiometabolic traits. In functional follow-up analyses, specifically in Drosophila RNAi-knockdowns, we observed a significant increase in the total body triglyceride levels for two genes (DNAH10 and PLXND1). We implicate novel genes in fat distribution, stressing the importance of interrogating low-frequency and protein-coding variants
Epidemic infectious gastrointestinal illness aboard U.S. Navy ships deployed to the Middle East during peacetime operations â 2000â2001
BACKGROUND: Infectious gastrointestinal illness (IGI) outbreaks have been reported in U.S. Navy ships and could potentially have an adverse mission impact. Studies to date have been anecdotal. METHODS: We conducted a retrospective analysis of weekly reported disease and non-battle injury health data collected in 2000 â 2001 from 44 U.S. Navy ships while sailing in the 5(th )Fleet (Persian Gulf and nearby seas). RESULTS: During this period, 11 possible IGI outbreaks were identified. Overall, we found 3.3 outbreaks per 100 ship-weeks, a mean outbreak duration of 4.4 weeks, and a mean cumulative ship population attack rate of 3.6%. Morbidity, represented by days lost due to personnel being placed on sick-in-quarters status, was higher during outbreak weeks compared to non-outbreak weeks (p = 0.002). No clear seasonal distribution was identified. CONCLUSION: Explosive outbreaks due to viruses and bacteria with the potential of incapacitating large proportions of the crew raise serious concerns of mission impact and military readiness
BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers
Background: The K3326X variant in BRCA2 (BRCA2*c.9976A>T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers.
Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided.
Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptorânegative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed.
Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations
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