657 research outputs found
Understanding Urban Demand for Wild Meat in Vietnam: Implications for Conservation Actions
Vietnam is a significant consumer of wildlife, particularly wild meat, in urban restaurant settings. To meet this demand, poaching of wildlife is widespread, threatening regional and international biodiversity. Previous interventions to tackle illegal and potentially unsustainable consumption of wild meat in Vietnam have generally focused on limiting supply. While critical, they have been impeded by a lack of resources, the presence of increasingly organised criminal networks and corruption. Attention is, therefore, turning to the consumer, but a paucity of research investigating consumer demand for wild meat will impede the creation of effective consumer-centred interventions. Here we used a mixed-methods research approach comprising a hypothetical choice modelling survey and qualitative interviews to explore the drivers of wild meat consumption and consumer preferences among residents of Ho Chi Minh City, Vietnam. Our findings indicate that demand for wild meat is heterogeneous and highly context specific. Wild-sourced, rare, and expensive wild meat-types are eaten by those situated towards the top of the societal hierarchy to convey wealth and status and are commonly consumed in lucrative business contexts. Cheaper, legal and farmed substitutes for wild-sourced meats are also consumed, but typically in more casual consumption or social drinking settings. We explore the implications of our results for current conservation interventions in Vietnam that attempt to tackle illegal and potentially unsustainable trade in and consumption of wild meat and detail how our research informs future consumer-centric conservation actions
Alternating Spin and Orbital Dimerization in Strong-coupling Two-band Models
We study a one-dimensional Hamiltonian consisting of coupled SU(2) spin and
orbital degrees of freedom. Using the density matrix renormalization group, we
calculate the phase-diagram and the ground state correlation functions for this
model. We find that, in addition to the ferromagnetic and power-law
antiferromagnetic phases for spin and orbital degrees of freedom, this model
has a gapless line extending from the ferromagnetic phase to the Bethe ansatz
solvable SU(4) critical point, and a gapped phase with doubly degenerate ground
states which form alternating spin and orbital singlets. The spin-gap and the
order parameters are evaluated and the relevance to several recently discovered
spin-gap materials is discussed.Comment: 4 pages REVTEX and 4 Postscript figure
The C4 Clustering Algorithm: Clusters of Galaxies in the Sloan Digital Sky Survey
We present the "C4 Cluster Catalog", a new sample of 748 clusters of galaxies
identified in the spectroscopic sample of the Second Data Release (DR2) of the
Sloan Digital Sky Survey (SDSS). The C4 cluster--finding algorithm identifies
clusters as overdensities in a seven-dimensional position and color space, thus
minimizing projection effects which plagued previous optical clusters
selection. The present C4 catalog covers ~2600 square degrees of sky with
groups containing 10 members to massive clusters having over 200 cluster
members with redshifts. We provide cluster properties like sky location, mean
redshift, galaxy membership, summed r--band optical luminosity (L_r), velocity
dispersion, and measures of substructure. We use new mock galaxy catalogs to
investigate the sensitivity to the various algorithm parameters, as well as to
quantify purity and completeness. These mock catalogs indicate that the C4
catalog is ~90% complete and 95% pure above M_200 = 1x10^14 solar masses and
within 0.03 <=z <= 0.12. The C4 algorithm finds 98% of X-ray identified
clusters and 90% of Abell clusters within 0.03 <= z <= 0.12. We show that the
L_r of a cluster is a more robust estimator of the halo mass (M_200) than the
line-of-sight velocity dispersion or the richness of the cluster. L_r. The
final SDSS data will provide ~2500 C4 clusters and will represent one of the
largest and most homogeneous samples of local clusters.Comment: 32 pages of figures and text accepted in AJ. Electronic version with
additional tables, links, and figures is available at
http://www.ctio.noao.edu/~chrism/c
Strengthen causal models for better conservation outcomes for human well-being.
BACKGROUND: Understanding how the conservation of nature can lead to improvement in human conditions is a research area with significant growth and attention. Progress towards effective conservation requires understanding mechanisms for achieving impact within complex social-ecological systems. Causal models are useful tools for defining plausible pathways from conservation actions to impacts on nature and people. Evaluating the potential of different strategies for delivering co-benefits for nature and people will require the use and testing of clear causal models that explicitly define the logic and assumptions behind cause and effect relationships. OBJECTIVES AND METHODS: In this study, we outline criteria for credible causal models and systematically evaluated their use in a broad base of literature (~1,000 peer-reviewed and grey literature articles from a published systematic evidence map) on links between nature-based conservation actions and human well-being impacts. RESULTS: Out of 1,027 publications identified, only ~20% of articles used any type of causal models to guide their work, and only 14 total articles fulfilled all criteria for credibility. Articles rarely tested the validity of models with empirical data. IMPLICATIONS: Not using causal models risks poorly defined strategies, misunderstanding of potential mechanisms for affecting change, inefficient use of resources, and focusing on implausible efforts for achieving sustainability
Feedback from galactic stellar bulges and hot gaseous haloes of galaxies
We demonstrate that the feedback from stellar bulges can play an essential
role in shaping the halo gas of galaxies with substantial bulge components by
conducting 1-D hydrodynamical simulations. The feedback model we consider
consists of two distinct phases: 1) an early starburst during the bulge
formation and 2) a subsequent long-lasting mass and energy injection from
stellar winds of low-mass stars and Type Ia SNe. An energetic outward blastwave
is initiated by the starburst and is maintained and enhanced by the
long-lasting stellar feedback. For a MW-like galactic bulge, this blastwave
sweeps up the halo gas in the proto-galaxy and heats up the surrounding medium
to a scale much beyond the virial radius of the halo, thus the accretion of the
halo hot gas can be completely stopped. In addition, the long-lasting feedback
in the later phase powers a galactic bulge wind that is reverse-shocked at a
large radius in the presence of surrounding intergalactic medium and hence
maintains a hot gaseous halo. As the mass and energy injection decreases with
time, the feedback evolves to a subsonic and quasi-stable outflow, which is
enough to prevent halo gas from cooling. The two phases of the feedback thus
re-enforce each-other's impact on the gas dynamics. The simulation results
demonstrate that the stellar bulge feedback may provide a plausible solution to
the long-standing problems in understanding the MW type galaxies, such as the
"missing stellar feedback" problem and the "over-cooling" problem. The
simulations also show that the properties of the hot gas in the subsonic
outflow state depend sensitively on the environment and the formation history
of the bulge. This dependence and variance may explain the large dispersion in
the X-ray to B-band luminosity ratio of the low Es.Comment: v2, discussions added, accepted for publication in MNRA
Coronary Atherosclerosis in Indigenous South American Tsimane: A Cross-Sectional Cohort Study
Background—Conventional coronary artery disease risk factors might potentially explain at least 90% of the attributable risk of coronary artery disease. To better understand the association between the pre-industrial lifestyle and low prevalence of coronary artery disease risk factors, we examined the Tsimane, a Bolivian population living a subsistence lifestyle of hunting, gathering, fishing, and farming with few cardiovascular risk factors, but high infectious inflammatory burden.
Methods—We did a cross-sectional cohort study including all individuals who self-identified as Tsimane and who were aged 40 years or older. Coronary atherosclerosis was assessed by coronary artery calcium (CAC) scoring done with non-contrast CT in Tsimane adults. We assessed the difference between the Tsimane and 6814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA). CAC scores higher than 100 were considered representative of significant atherosclerotic disease. Tsimane blood lipid and inflammatory biomarkers were obtained at the time of scanning, and in some patients, longitudinally.
Findings—Between July 2, 2014, and Sept 10, 2015, 705 individuals, who had data available for analysis, were included in this study. 596 (85%) of 705 Tsimane had no CAC, 89 (13%) had CAC scores of 1–100, and 20 (3%) had CAC scores higher than 100. For individuals older than age 75 years, 31 (65%) Tsimane presented with a CAC score of 0, and only four (8%) had CAC scores of 100 or more, a five-fold lower prevalence than industrialised populations (p≤0-0001 for all age categories of MESA). Mean LDL and HDL cholesterol concentrations were 2.35 mmol/L (91 mg/dL) and 1.0 mmol/L (39.5 mg/dL), respectively; obesity, hypertension, high blood sugar, and regular cigarette smoking were rare. High- sensitivity C-reactive protein was elevated beyond the clinical cutoff of 3.0 mg/dL in 360 (51%) Tsimane participants.
Interpretation—Despite a high infectious inflammatory burden, the Tsimane, a forager-horticulturalist population of the Bolivian Amazon with few coronary artery disease risk factors, have the lowest reported levels of coronary artery disease of any population recorded to date. These findings suggest that coronary atherosclerosis can be avoided in most people by achieving a lifetime with very low LDL, low blood pressure, low glucose, normal body-mass index, no smoking, and plenty of physical activity. The relative contributions of each are still to be determined
Bostonia: The Boston University Alumni Magazine. Volume 10
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Epidemiology of Subpatent Plasmodium Falciparum Infection: Implications for Detection of Hotspots with Imperfect Diagnostics.
At the local level, malaria transmission clusters in hotspots, which may be a group of households that experience higher than average exposure to infectious mosquitoes. Active case detection often relying on rapid diagnostic tests for mass screen and treat campaigns has been proposed as a method to detect and treat individuals in hotspots. Data from a cross-sectional survey conducted in north-western Tanzania were used to examine the spatial distribution of Plasmodium falciparum and the relationship between household exposure and parasite density. Dried blood spots were collected from consenting individuals from four villages during a survey conducted in 2010. These were analysed by PCR for the presence of P. falciparum, with the parasite density of positive samples being estimated by quantitative PCR. Household exposure was estimated using the distance-weighted PCR prevalence of infection. Parasite density simulations were used to estimate the proportion of infections that would be treated using a screen and treat approach with rapid diagnostic tests (RDT) compared to targeted mass drug administration (tMDA) and Mass Drug Administration (MDA). Polymerase chain reaction PCR analysis revealed that of the 3,057 blood samples analysed, 1,078 were positive. Mean distance-weighted PCR prevalence per household was 34.5%. Parasite density was negatively associated with transmission intensity with the odds of an infection being subpatent increasing with household exposure (OR 1.09 per 1% increase in exposure). Parasite density was also related to age, being highest in children five to ten years old and lowest in those > 40 years. Simulations of different tMDA strategies showed that treating all individuals in households where RDT prevalence was above 20% increased the number of infections that would have been treated from 43 to 55%. However, even with this strategy, 45% of infections remained untreated. The negative relationship between household exposure and parasite density suggests that DNA-based detection of parasites is needed to provide adequate sensitivity in hotspots. Targeting MDA only to households with RDT-positive individuals may allow a larger fraction of infections to be treated. These results suggest that community-wide MDA, instead of screen and treat strategies, may be needed to successfully treat the asymptomatic, subpatent parasite reservoir and reduce transmission in similar settings
Prevalence of Dementia and Mild Cognitive Impairment in Indigenous Bolivian Forager-Horticulturalists
Introduction
We evaluated the prevalence of dementia and mild cognitive impairment (MCI) in indigenous Tsimane and Moseten, who lead a subsistence lifestyle. Methods
Participants from population-based samples ≥ 60 years of age (n = 623) were assessed using adapted versions of the Modified Mini-Mental State Examination, informant interview, longitudinal cognitive testing and brain computed tomography (CT) scans. Results
Tsimane exhibited five cases of dementia (among n = 435; crude prevalence = 1.2%, 95% confidence interval [CI]: 0.4, 2.7); Moseten exhibited one case (among n = 169; crude prevalence = 0.6%, 95% CI: 0.0, 3.2), all age ≥ 80 years. Age-standardized MCI prevalence was 7.7% (95% CI: 5.2, 10.3) in Tsimane and 9.8% (95% CI: 4.9, 14.6) in Moseten. Cognitive impairment was associated with visuospatial impairments, parkinsonian symptoms, and vascular calcification in the basal ganglia. Discussion
The prevalence of dementia in this cohort is among the lowest in the world. Widespread intracranial medial arterial calcifications suggest a previously unrecognized, non-Alzheimer\u27s disease (AD) dementia phenotype
Anomalous Pseudoscalar-Photon Vertex In and Out of Equilibrium
The anomalous pseudoscalar-photon vertex is studied in real time in and out
of equilibrium in a constituent quark model. The goal is to understand the
in-medium modifications of this vertex, exploring the possibility of enhanced
isospin breaking by electromagnetic effects as well as the formation of neutral
pion condensates in a rapid chiral phase transition in peripheral,
ultrarelativistic heavy-ion collisions. In equilibrium the effective vertex is
afflicted by infrared and collinear singularities that require hard thermal
loop (HTL) and width corrections of the quark propagator. The resummed
effective equilibrium vertex vanishes near the chiral transition in the chiral
limit. In a strongly out of equilibrium chiral phase transition we find that
the chiral condensate drastically modifies the quark propagators and the
effective vertex. The ensuing dynamics for the neutral pion results in a
potential enhancement of isospin breaking and the formation of
condensates. While the anomaly equation and the axial Ward identity are not
modified by the medium in or out of equilibrium, the effective real-time
pseudoscalar-photon vertex is sensitive to low energy physics.Comment: Revised version to appear in Phys. Rev. D. 42 pages, 4 figures, uses
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