324 research outputs found
Teff and log g dependence of velocity fields in M-stars
We present an investigation of velocity fields in early to late M-type
hydrodynamic stellar atmosphere models. These velocities will be expressed in
classical terms of micro- and macro-turbulent velocities for usage in 1D
spectral synthesis. The M-star model parameters range between log g of 3.0 -
5.0 and Teff of 2500 K - 4000 K. We characterize the Teff- and log g-dependence
of the hydrodynamical velocity fields in these models with a binning method,
and for the determination of micro-turbulent velocities, the Curve of Growth
method is used. The macro-turbulent velocities are obtained by convolutions
with Gaussian profiles. Velocity fields in M-stars strongly depend on log g and
Teff. Their velocity amplitudes increase with decreasing log g and increasing
Teff. The 3D hydrodynamical and 1D macro-turbulent velocities range from ~100
m/s for cool high gravity models to ~ 800 m/s - 1000 m/s for hot models or
models with low log g. The micro-turbulent velocities range in the order of
~100 m/s for cool models, to ~600 m/s for hot or low log g models. Our M-star
structure models are calculated with the 3D radiative-hydrodynamics (RHD) code
CO5BOLD. The spectral synthesis on these models is performed with the line
synthesis code LINFOR3D.Comment: 8 pages, 6 Figures, Proceeding fot the "Recent directions in
astrophysical quantitative spectroscopy and radiation hydrodynamics"
conferenc
Evaluating the importance of the convex hull in solving the Euclidean version of the traveling salesperson problem: Reply to Lee and Vickers (2000)
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Surfaces: An interdisciplinary project to understand and enhance health in the vulnerable rainforests of Papua New Guinea
Background
New Guinea has the third largest tropical rainforest on Earth. However, one quarter of the forests of Papua New Guinea (PNG, New Guinea’s eastern half) have been cleared or degraded, nearly half through commercial logging.Sustainable development requires supporting good health (Sustainable Development Goal [SDG] 3) and protecting life on land (SDG 15). To remote communities in PNG with low levels of health provision, these goals can seem in conflict. Logging companies’ offer of roads and income can partly extinguish the remoteness that bars access to health services, making desire for health a driver for forest destruction and erosion of health related ecosystem services. Conservation success thus requires synergies be developed with delivery of other SDGs, particularly those pertaining to health. We aim to provide a model of integrated health and conservation in PNGs rainforests.
Methods
We are mapping and piloting biological, anthropological, and medical methods to address SDGs on health and biodiversity, focusing first on scabies and fungal diseases. At Wanang, team members have a long term collaboration with nine clans with unmet health needs who collectively chose to preserve their 10,000 hectare forest whilst surrounding communities allowed logging. Similar collaborations are being developed along an altitudinal transect on Mt.Wilheim (4,509m). Stage 1 of Surfaces will (i) systematically map evidence on integrated conservation and health programmes, (ii) conduct clinical examinations and rapid anthropological assessments to understand medical needs, and survey skin disease, and (iii) produce a case study of the Wanang agreement, based on interviews with participants. This will lay the foundation for a multi-year health intervention and interdisciplinary study.
Findings
We are in the projects’ early stages (so do not yet have findings), and would appreciate advice and suggestions of collaboration from others in the Planetary Health community.
Funding
Sussex Sustainability Research Programme, University of Sussex, UK.
Contributions
All authors have commented on multiple drafts and approved the final version of the abstract for publication.
Conflicts of interest
We declare we have no conflicts of interest.
Acknowledgments
We thank the projects partner communities; New Guinea Binatang Research Centre; and our advisory group
Endothelin-1 Predicts Hemodynamically Assessed Pulmonary Arterial Hypertension in HIV Infection.
BackgroundHIV infection is an independent risk factor for PAH, but the underlying pathogenesis remains unclear. ET-1 is a robust vasoconstrictor and key mediator of pulmonary vascular homeostasis. Higher levels of ET-1 predict disease severity and mortality in other forms of PAH, and endothelin receptor antagonists are central to treatment, including in HIV-associated PAH. The direct relationship between ET-1 and PAH in HIV-infected individuals is not well described.MethodsWe measured ET-1 and estimated pulmonary artery systolic pressure (PASP) with transthoracic echocardiography (TTE) in 106 HIV-infected individuals. Participants with a PASP ≥ 30 mmHg (n = 65) underwent right heart catheterization (RHC) to definitively diagnose PAH. We conducted multivariable analysis to identify factors associated with PAH.ResultsAmong 106 HIV-infected participants, 80% were male, the median age was 52 years and 77% were on antiretroviral therapy. ET-1 was significantly associated with higher values of PASP [14% per 0.1 pg/mL increase in ET-1, p = 0.05] and PASP ≥ 30 mmHg [PR (prevalence ratio) = 1.24, p = 0.012] on TTE after multivariable adjustment for PAH risk factors. Similarly, among the 65 individuals who underwent RHC, ET-1 was significantly associated with higher values of mean pulmonary artery pressure and PAH (34%, p = 0.003 and PR = 2.43, p = 0.032, respectively) in the multivariable analyses.ConclusionsHigher levels of ET-1 are independently associated with HIV-associated PAH as hemodynamically assessed by RHC. Our findings suggest that excessive ET-1 production in the setting of HIV infection impairs pulmonary endothelial function and contributes to the development of PAH
Convex hull or crossing avoidance? Solution heuristics in the traveling salesperson problem
Author Correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases.
Emmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article
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Miles to go (mtgo) encodes FNDC3 proteins that interact with the chaperonin subunit CCT3 and are required for NMJ branching and growth in Drosophila.
Analysis of mutants that affect formation and function of the Drosophila larval neuromuscular junction (NMJ) has provided valuable insight into genes required for neuronal branching and synaptic growth. We report that NMJ development in Drosophila requires both the Drosophila ortholog of FNDC3 genes; CG42389 (herein referred to as miles to go; mtgo), and CCT3, which encodes a chaperonin complex subunit. Loss of mtgo function causes late pupal lethality with most animals unable to escape the pupal case, while rare escapers exhibit an ataxic gait and reduced lifespan. NMJs in mtgo mutant larvae have dramatically reduced branching and growth and fewer synaptic boutons compared with control animals. Mutant larvae show normal locomotion but display an abnormal self-righting response and chemosensory deficits that suggest additional functions of mtgo within the nervous system. The pharate lethality in mtgo mutants can be rescued by both low-level pan- and neuronal-, but not muscle-specific expression of a mtgo transgene, supporting a neuronal-intrinsic requirement for mtgo in NMJ development. Mtgo encodes three similar proteins whose domain structure is most closely related to the vertebrate intracellular cytosolic membrane-anchored fibronectin type-III domain-containing protein 3 (FNDC3) protein family. Mtgo physically and genetically interacts with Drosophila CCT3, which encodes a subunit of the TRiC/CCT chaperonin complex required for maturation of actin, tubulin and other substrates. Drosophila larvae heterozygous for a mutation in CCT3 that reduces binding between CCT3 and MTGO also show abnormal NMJ development similar to that observed in mtgo null mutants. Hence, the intracellular FNDC3-ortholog MTGO and CCT3 can form a macromolecular complex, and are both required for NMJ development in Drosophila
Low Energy Nuclear Reaction Aircraft- 2013 ARMD Seedling Fund Phase I Project
This report serves as the final written documentation for the Aeronautic Research Mission Directorate (ARMD) Seedling Fund's Low Energy Nuclear Reaction (LENR) Aircraft Phase I project. The findings presented include propulsion system concepts, synergistic missions, and aircraft concepts. LENR is a form of nuclear energy that potentially has over 4,000 times the energy density of chemical energy sources. It is not expected to have any harmful emissions or radiation which makes it extremely appealing. There is a lot of interest in LENR, but there are no proven theories. This report does not explore the feasibility of LENR. Instead, it assumes that a working system is available. A design space exploration shows that LENR can enable long range and high speed missions. Six propulsion concepts, six missions, and four aircraft concepts are presented. This report also includes discussion of several issues and concerns that were uncovered during the study and potential research areas to infuse LENR aircraft into NASA's aeronautics research
Health service needs and perspectives of remote forest communities in Papua New Guinea: study protocol for combined clinical and rapid anthropological assessments with parallel treatment of urgent cases
Introduction
Our project follows community requests for health service incorporation into conservation collaborations in the rainforests of Papua New Guinea (PNG). This protocol is for health needs assessments, our first step in coplanning medical provision in communities with no existing health data.
Methods and analysis
The study includes clinical assessments and rapid anthropological assessment procedures (RAP) exploring the health needs and perspectives of partner communities in two areas, conducted over 6 weeks fieldwork. First, in Wanang village (population c.200), which is set in lowland rainforest. Second, in six communities (population c.3000) along an altitudinal transect up the highest mountain in PNG, Mount Wilhelm. Individual primary care assessments incorporate physical examinations and questioning (providing qualitative and quantitative data) while RAP includes focus groups, interviews and field observations (providing qualitative data). Given absence of in-community primary care, treatments are offered alongside research activity but will not form part of the study. Data are collected by a research fellow, primary care clinician and two PNG research technicians. After quantitative and qualitative analyses, we will report: ethnoclassifications of disease, causes, symptoms and perceived appropriate treatment; community rankings of disease importance and service needs; attitudes regarding health service provision; disease burdens and associations with altitudinal-related variables and cultural practices. To aid wider use study tools are in online supplemental file, and paper and ODK versions are available free from the corresponding author.
Ethics and dissemination
Challenges include supporting informed consent in communities with low literacy and diverse cultures, moral duties to provide treatment alongside research in medically underserved areas while minimising risks of therapeutic misconception and inappropriate inducement, and PNG research capacity building. Brighton and Sussex Medical School (UK), PNG Institute of Medical Research and PNG Medical Research Advisory Committee have approved the study. Dissemination will be via journals, village meetings and plain language summaries
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