167 research outputs found
Extracting the rho meson wavefunction from HERA data
We extract the light-cone wavefunctions of the rho meson using the HERA data
on diffractive rho photoproduction. We find good agreement with predictions for
the distribution amplitude based on QCD sum rules and from the lattice. We also
find that the data prefer a transverse wavefunction with enhanced end-point
contributions.Comment: 13 pages, 7 figures, significant improvements over the original
version with a new section on distribution amplitudes adde
Extracting the Distribution Amplitudes of the rho meson from the Color Glass Condensate
We extract the leading twist-2 and subleading twist-3 Distribution Amplitudes
(DAs) of the rho meson using the HERA data on diffractive rho photoproduction.
We do so using several Colour Glass Condensate (CGC) inspired and a Regge
inspired dipole models. We find that our extracted twist-2 DA is not much model
dependent and is consistent with QCD Sum Rules and lattice predictions. The
extracted twist-3 DA is more model dependent but is still consistent with the
Sum Rules prediction.Comment: 21 pages, 10 figures, 3 tables. Section 6 revised, figures 8 and 9
and table 3 updated. Conclusions essentially unchange
How large should whales be?
The evolution and distribution of species body sizes for terrestrial mammals
is well-explained by a macroevolutionary tradeoff between short-term selective
advantages and long-term extinction risks from increased species body size,
unfolding above the 2g minimum size induced by thermoregulation in air. Here,
we consider whether this same tradeoff, formalized as a constrained
convection-reaction-diffusion system, can also explain the sizes of fully
aquatic mammals, which have not previously been considered. By replacing the
terrestrial minimum with a pelagic one, at roughly 7000g, the terrestrial
mammal tradeoff model accurately predicts, with no tunable parameters, the
observed body masses of all extant cetacean species, including the 175,000,000g
Blue Whale. This strong agreement between theory and data suggests that a
universal macroevolutionary tradeoff governs body size evolution for all
mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus
be attributed mainly to the increased convective heat loss is water, which
shifts the species size distribution upward and pushes its right tail into
ranges inaccessible to terrestrial mammals. Under this macroevolutionary
tradeoff, the largest expected species occurs where the rate at which
smaller-bodied species move up into large-bodied niches approximately equals
the rate at which extinction removes them.Comment: 7 pages, 3 figures, 2 data table
Transboundary health impacts of transported global air pollution and international trade
Millions of people die every year from diseases caused by exposure to outdoor air pollution1, 2, 3, 4, 5. Some studies have estimated premature mortality related to local sources of air pollution6, 7, but local air quality can also be affected by atmospheric transport of pollution from distant sources8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18. International trade is contributing to the globalization of emission and pollution as a result of the production of goods (and their associated emissions) in one region for consumption in another region14, 19, 20, 21, 22. The effects of international trade on air pollutant emissions23, air quality14 and health24 have been investigated regionally, but a combined, global assessment of the health impacts related to international trade and the transport of atmospheric air pollution is lacking. Here we combine four global models to estimate premature mortality caused by fine particulate matter (PM2.5) pollution as a result of atmospheric transport and the production and consumption of goods and services in different world regions. We find that, of the 3.45 million premature deaths related to PM2.5 pollution in 2007 worldwide, about 12 per cent (411,100 deaths) were related to air pollutants emitted in a region of the world other than that in which the death occurred, and about 22 per cent (762,400 deaths) were associated with goods and services produced in one region for consumption in another. For example, PM2.5 pollution produced in China in 2007 is linked to more than 64,800 premature deaths in regions other than China, including more than 3,100 premature deaths in western Europe and the USA; on the other hand, consumption in western Europe and the USA is linked to more than 108,600 premature deaths in China. Our results reveal that the transboundary health impacts of PM2.5 pollution associated with international trade are greater than those associated with long-distance atmospheric pollutant transport
Climate warming, marine protected areas and the ocean-scale integrity of coral reef ecosystems
Coral reefs have emerged as one of the ecosystems most vulnerable to climate variation and change. While the contribution
of a warming climate to the loss of live coral cover has been well documented across large spatial and temporal scales, the
associated effects on fish have not. Here, we respond to recent and repeated calls to assess the importance of local
management in conserving coral reefs in the context of global climate change. Such information is important, as coral reef
fish assemblages are the most species dense vertebrate communities on earth, contributing critical ecosystem functions
and providing crucial ecosystem services to human societies in tropical countries. Our assessment of the impacts of the
1998 mass bleaching event on coral cover, reef structural complexity, and reef associated fishes spans 7 countries, 66 sites
and 26 degrees of latitude in the Indian Ocean. Using Bayesian meta-analysis we show that changes in the size structure,
diversity and trophic composition of the reef fish community have followed coral declines. Although the ocean scale
integrity of these coral reef ecosystems has been lost, it is positive to see the effects are spatially variable at multiple scales,
with impacts and vulnerability affected by geography but not management regime. Existing no-take marine protected areas
still support high biomass of fish, however they had no positive affect on the ecosystem response to large-scale disturbance.
This suggests a need for future conservation and management efforts to identify and protect regional refugia, which should
be integrated into existing management frameworks and combined with policies to improve system-wide resilience to
climate variation and change
A New Direction to Athletic Performance: Understanding the Acute and Longitudinal Responses to Backward Running
Backward running (BR) is a form of locomotion that occurs in short bursts during many overground field and court sports. It has also traditionally been used in clinical settings as a method to rehabilitate lower body injuries. Comparisons between BR and forward running (FR) have led to the discovery that both may be generated by the same neural circuitry. Comparisons of the acute responses to FR reveal that BR is characterised by a smaller ratio of braking to propulsive forces, increased step frequency, decreased step length, increased muscle activity and reliance on isometric and concentric muscle actions. These biomechanical differences have been critical in informing recent scientific explorations which have discovered that BR can be used as a method for reducing injury and improving a variety of physical attributes deemed advantageous to sports performance. This includes improved lower body strength and power, decreased injury prevalence and improvements in change of direction performance following BR training. The current findings from research help improve our understanding of BR biomechanics and provide evidence which supports BR as a useful method to improve athlete performance. However, further acute and longitudinal research is needed to better understand the utility of BR in athletic performance programs
Expansion in CD39(+) CD4(+) Immunoregulatory T Cells and Rarity of Th17 Cells in HTLV-1 Infected Patients Is Associated with Neurological Complications
HTLV-1 infection is associated with several inflammatory disorders, including the neurodegenerative condition HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It is unclear why a minority of infected subjects develops HAM/TSP. CD4(+) T cells are the main target of infection and play a pivotal role in regulating immunity to HTLV and are hypothesized to participate in the pathogenesis of HAM/TSP. the CD39 ectonucleotidase receptor is expressed on CD4(+) T cells and based on co-expression with CD25, marks T cells with distinct regulatory (CD39(+)CD25(+)) and effector (CD39(+)CD25(-)) function. Here, we investigated the expression of CD39 on CD4(+) T cells from a cohort of HAM/TSP patients, HTLV-1 asymptomatic carriers (AC), and matched uninfected controls. the frequency of CD39(+)CD4(+) T cells was increased in HTLV-1 infected patients, regardless of clinical status. More importantly, the proportion of the immunostimulatory CD39(+)CD25(-) CD4+ T-cell subset was significantly elevated in HAM/TSP patients as compared to AC and phenotypically had lower levels of the immunoinhibitory receptor, PD-1. We saw no difference in the frequency of CD39(+)CD25(+) regulatory (Treg) cells between AC and HAM/TSP patients. However, these cells transition from being anergic to displaying a polyfunctional cytokine response following HTLV-1 infection. CD39(-)CD25(+) T cell subsets predominantly secreted the inflammatory cytokine IL-17. We found that HAM/TSP patients had significantly fewer numbers of IL-17 secreting CD4(+) T cells compared to uninfected controls. Taken together, we show that the expression of CD39 is upregulated on CD4(+) T cells HAM/TSP patients. This upregulation may play a role in the development of the proinflammatory milieu through pathways both distinct and separate among the different CD39 T cell subsets. CD39 upregulation may therefore serve as a surrogate diagnostic marker of progression and could potentially be a target for interventions to reduce the development of HAM/TSP.National Institute of Allergies and Infectious DiseasesNational Institutes of HealthUniversity of CaliforniaSan Francisco-Gladstone Institute of Virology & Immunology Center for AIDS ResearchFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)John E. Fogarty International CenterNational Center for Research ResourcesNational Institute of General Medical Sciences from the National Institutes of HealthUniv Calif San Francisco, Dept Med, Div Expt Med, San Francisco, CA 94143 USAUniv Hawaii, John A Burns Sch Med, Dept Trop Med, Hawaii Ctr AIDS, Honolulu, HI 96822 USAUniv São Paulo, Sch Med, Deparment Infect Dis, São Paulo, BrazilUniv São Paulo, Sch Med, Div Clin Immunol & Allergy, São Paulo, BrazilFuncacao Prosangue, Hemoctr São Paulo, Mol Biol Lab, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Translat Med, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Translat Med, São Paulo, BrazilSan Francisco-Gladstone Institute of Virology & Immunology Center for AIDS Research: P30 AI027763FAPESP: 04/15856-9/KallasFAPESP: 2010/05845-0/KallasFAPESP: 11/12297-2/SanabaniJohn E. Fogarty International Center: D43 TW00003National Center for Research Resources: 5P20RR016467-11National Institute of General Medical Sciences from the National Institutes of Health: 8P20GM103466-11Web of Scienc
Gynaecological morbidity among HIV positive pregnant women in Cameroon
<p>Abstract</p> <p>Objective</p> <p>To compare the prevalence of gynaecological conditions among HIV infected and non-infected pregnant women.</p> <p>Methods</p> <p>Two thousand and eight (2008) pregnant women were screened for HIV, lower genital tract infections and lower genital tract neoplasia at booking antenatal visit.</p> <p>Results</p> <p>About 10% (198/2008) were HIV positive. All lower genital tract infections except candidiasis were more prevalent among HIV positive compared to HIV negative women: vaginal candidiasis (36.9% vs 35.4%; <it>p </it>= 0.678), Trichomoniasis (21.2% vs 10.6%; <it>p </it>< 0.001), gonorrhoea (10.1% vs 2.5%; <it>p </it>< 0.001), bacterial vaginosis (21.2% vs 15.2%; <it>p </it>= 0.026), syphilis (35.9% vs 10.6%; <it>p </it>< 0.001), and <it>Chlamydia trachomatis </it>(38.4% vs 7.1%; <it>p </it>< 0.001). Similarly, HIV positive women more likely to have preinvasive cervical lesions: low-grade squamous intraepithelial lesion (SIL) (18.2% vs 4.4%; <it>p </it>< 0.001) and high-grade squamous intraepithelial lesion (12.1% vs 1.5%; <it>p </it>< 0.001).</p> <p>Conclusion</p> <p>We conclude that (i) sexually transmitted infections (STIs) are common in both HIV positive and HIV negative pregnant women in Cameroon, and (ii) STIs and preinvasive cervical lesions are more prevalent in HIV-infected pregnant women compared to their non-infected compatriots. We recommend routine screening and treatment of STIs during antenatal care in Cameroon and other countries with similar social profiles.</p
Parton distributions for the LHC run II
We present NNPDF3.0, the first set of parton distribution functions (PDFs)
determined with a methodology validated by a closure test. NNPDF3.0 uses a
global dataset including HERA-II deep-inelastic inclusive cross-sections, the
combined HERA charm data, jet production from ATLAS and CMS, vector boson
rapidity and transverse momentum distributions from ATLAS, CMS and LHCb, W+c
data from CMS and top quark pair production total cross sections from ATLAS and
CMS. Results are based on LO, NLO and NNLO QCD theory and also include
electroweak corrections. To validate our methodology, we show that PDFs
determined from pseudo-data generated from a known underlying law correctly
reproduce the statistical distributions expected on the basis of the assumed
experimental uncertainties. This closure test ensures that our methodological
uncertainties are negligible in comparison to the generic theoretical and
experimental uncertainties of PDF determination. This enables us to determine
with confidence PDFs at different perturbative orders and using a variety of
experimental datasets ranging from HERA-only up to a global set including the
latest LHC results, all using precisely the same validated methodology. We
explore some of the phenomenological implications of our results for the
upcoming 13 TeV Run of the LHC, in particular for Higgs production
cross-sections.Comment: 151 pages, 69 figures. More typos corrected: published versio
Gender and race influence metabolic benefits of fitness in children: a cross-sectional study
<p>Abstract</p> <p>Background</p> <p>Increasing obesity and poor cardiovascular fitness (CVF) contribute to higher rates of type 2 diabetes mellitus (T2DM) in children. While the relative contributions of fitness and body fat on development of insulin resistance (IR) in children and adolescents remains unresolved, gender- and race-specific differences likely exist in the degree to which CVF influences IR and risk for T2DM. Better understanding of how gender and race affect interactions between body fat, CVF, and metabolic health would be helpful in designing effective and targeted strategies to reduce obesity-associated disease risk. We evaluated whether metabolic benefits of fitness on reducing inflammation and insulin resistance (IR) are affected by gender and race.</p> <p>Methods</p> <p>This cross-sectional study included 203 healthy children (mean age 12.2 y, 50% male, 46% non-Hispanic white (NHW), 54% racially diverse (RD)). Fasting insulin, glucose, hsCRP, and adiponectin were measured; race was self-reported; cardiovascular fitness (CVF) was evaluated by the Progressive Aerobic Cardiovascular Endurance Run. Associations between inflammation and gender, race, and CVF were evaluated using analysis of covariance. Multivariate regression analysis identified independent predictors of IR.</p> <p>Results</p> <p>Fitness and inflammation were inversely related in both males and females (p < 0.01); this effect was marginally stronger in RD children (p = 0.06) and non-overweight males (p = 0.07). High BMI (p < 0.001), low fitness (p = 0.006), and (female) gender (p = 0.003) were independently associated with higher HOMA-IR. In males, BMI and fitness, but not race independently predicted HOMA-IR. In females, BMI and race, but not fitness independently predicted HOMA-IR.</p> <p>Conclusions</p> <p>In middle school children, the beneficial effects of fitness vary based on gender and race. High CVF has an enhanced anti-inflammatory effect in male and RD children. While BMI is the strongest predictor of IR in the study group as a whole, fitness is a significant predictor of IR only in males, and race is a significant predictor of IR only in females.</p
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