60 research outputs found
Dualities in all order finite N=1 gauge theories
We search for dual gauge theories of all-loop finite, N = 1 supersymmetric
gauge theories. It is shown how to find explicitly the dual gauge theories of
almost all chiral, N = 1, all-loop finite gauge theories, while several models
have been discussed in detail, including a realistic finite SU(5) unified
theory. Out of our search only one all-loop, N = 1 finite SO(10) theory
emerges, so far, as a candidate for exhibiting also S-duality.Comment: 54 pages, latex, 2 figure
Cut-points for waist circumference in Europids and South Asians
There is little strong evidence that currently recommended higher waist circumference cut-points for Europids compared with South Asians are associated with similar risk for type 2 diabetes. This study was designed to provide such evidence. Longitudinal studies over 5 years were conducted among 5,515 Europid and 2,214 ethnically South Asian participants. Age-standardized diabetes incidence at different levels of waist circumference and incidence difference relative to a reference value were calculated. The Youden Index was used to determine waist circumference cut-points. At currently recommended cut-points, estimated annual diabetes incidence for a 50-year-old Europid was <0.6% for both sexes, and for a 50-year-old South Asian, 5.8% for men and 2.1% for women. Annual diabetes incidence of 1% was observed for a 50 year old at a waist circumference 35–40 cm greater in Europid compared to South Asian men and women. Incidence difference between recommended cut-points and a reference value (80 cm in men, 70 cm in women) was 0.3 and 4.4% per year for Europid and South Asian men, and 0.2 and 0.8% per year for Europid and South Asian women, respectively. Waist circumference cut-points chosen using the Youden Index were shown to be dependent on obesity levels in the population. The much higher observed risk of diabetes in South Asians compared to Europids at the respective recommended waist circumference cut-points suggests that differences between them should be greater. Approaches that use the Youden Index to select waist circumference cut-points are inappropriate and should not be used for this purpose.<br /
A Proton Leak Current through the Cardiac Sodium Channel Is Linked to Mixed Arrhythmia and the Dilated Cardiomyopathy Phenotype
Cardiac Na+ channels encoded by the SCN5A gene are essential for initiating heart beats and maintaining a regular heart rhythm. Mutations in these channels have recently been associated with atrial fibrillation, ventricular arrhythmias, conduction disorders, and dilated cardiomyopathy (DCM)
Modeling the Role of Alkanes, Polycyclic Aromatic Hydrocarbons, and Their Oligomers in Secondary Organic Aerosol Formation
A computationally efficient method to treat secondary
organic aerosol (SOA) from various length and structure alkanes as
well as SOA from polycyclic aromatic hydrocarbons (PAHs) is implemented
in the Community Multiscale Air Quality (CMAQ) model to predict aerosol
concentrations over the United States. Oxidation of alkanes is predicted
to produce more aerosol than oxidation of PAHs driven by relatively
higher alkane emissions. SOA from alkanes and PAHs, although small
in magnitude, can be a substantial fraction of the SOA from anthropogenic
hydrocarbons, particularly in winter, and could contribute more if
emission inventories lack intermediate volatility alkanes (>C<sub>13</sub>) or if the vehicle fleet shifts toward diesel-powered vehicles.
The SOA produced from oxidation of alkanes correlates well with ozone
and odd oxygen in many locations, but the lower correlation of anthropogenic
oligomers with odd oxygen indicates that models may need additional
photochemically dependent pathways to low-volatility SOA
Development of the crop residue and rangeland burning in the 2014 National Emissions Inventory using information from multiple sources
<p>Biomass burning has been identified as an important contributor to the degradation of air quality because of its impact on ozone and particulate matter. One component of the biomass burning inventory, crop residue burning, has been poorly characterized in the National Emissions Inventory (NEI). In the 2011 NEI, wildland fires, prescribed fires, and crop residue burning collectively were the largest source of PM<sub>2.5</sub>. This paper summarizes our 2014 NEI method to estimate crop residue burning emissions and grass/pasture burning emissions using remote sensing data and field information and literature-based, crop-specific emission factors. We focus on both the postharvest and pre-harvest burning that takes place with bluegrass, corn, cotton, rice, soybeans, sugarcane and wheat. Estimates for 2014 indicate that over the continental United States (CONUS), crop residue burning excluding all areas identified as Pasture/Grass, Grassland Herbaceous, and Pasture/Hay occurred over approximately 1.5 million acres of land and produced 19,600 short tons of PM<sub>2.5</sub>. For areas identified as Pasture/Grass, Grassland Herbaceous, and Pasture/Hay, biomass burning emissions occurred over approximately 1.6 million acres of land and produced 30,000 short tons of PM<sub>2.5</sub>. This estimate compares with the 2011 NEI and 2008 NEI as follows: 2008: 49,650 short tons and 2011: 141,180 short tons. Note that in the previous two NEIs rangeland burning was not well defined and so the comparison is not exact. The remote sensing data also provided verification of our existing diurnal profile for crop residue burning emissions used in chemical transport modeling. In addition, the entire database used to estimate this sector of emissions is available on EPA’s Clearinghouse for Inventories and Emission Factors (CHIEF, <a href="http://www3.epa.gov/ttn/chief/index.html" target="_blank">http://www3.epa.gov/ttn/chief/index.html</a>).<i>Implications</i>: Estimates of crop residue burning and rangeland burning emissions can be improved by using satellite detections. Local information is helpful in distinguishing crop residue and rangeland burning from all other types of fires.</p
Predicting the Effects of Nanoscale Cerium Additives in Diesel Fuel on Regional-Scale Air Quality
Diesel vehicles are a major source
of air pollutant emissions.
Fuel additives containing nanoparticulate cerium (nCe) are currently
being used in some diesel vehicles to improve fuel efficiency. These
fuel additives also reduce fine particulate matter (PM<sub>2.5</sub>) emissions and alter the emissions of carbon monoxide (CO), nitrogen
oxides (NO<sub><i>x</i></sub>), and hydrocarbon (HC) species,
including several hazardous air pollutants (HAPs). To predict their
net effect on regional air quality, we review the emissions literature
and develop a multipollutant inventory for a hypothetical scenario
in which nCe additives are used in all on-road and nonroad diesel
vehicles. We apply the Community Multiscale Air Quality (CMAQ) model
to a domain covering the eastern U.S. for a summer and a winter period.
Model calculations suggest modest decreases of average PM<sub>2.5</sub> concentrations and relatively larger decreases in particulate elemental
carbon. The nCe additives also have an effect on 8 h maximum ozone
in summer. Variable effects on HAPs are predicted. The total U.S.
emissions of fine-particulate cerium are estimated to increase 25-fold
and result in elevated levels of airborne cerium (up to 22 ng/m<sup>3</sup>), which might adversely impact human health and the environment
Community Vulnerability to Health Impacts of Wildland Fire Smoke Exposure
Identifying
communities vulnerable to adverse health effects from
exposure to wildfire smoke may help prepare responses, increase the
resilience to smoke and improve public health outcomes during smoke
days. We developed a Community Health-Vulnerability Index (CHVI) based
on factors known to increase the risks of health effects from air
pollution and wildfire smoke exposures. These factors included county
prevalence rates for asthma in children and adults, chronic obstructive
pulmonary disease, hypertension, diabetes, obesity, percent of population
65 years of age and older, and indicators of socioeconomic status
including poverty, education, income and unemployment. Using air quality
simulated for the period between 2008 and 2012 over the continental
U.S. we also characterized the population size at risk with respect
to the level and duration of exposure to fire-originated fine particulate
matter (fire-PM<sub>2.5</sub>) and CHVI. We estimate that 10% of the
population (30.5 million) lived in the areas where the contribution
of fire-PM<sub>2.5</sub> to annual average ambient PM<sub>2.5</sub> was high (>1.5 μg/m<sup>3</sup>) and that 10.3 million
individuals
experienced unhealthy air quality levels for more than 10 days due
to smoke. Using CHVI we identified the most vulnerable counties and
determined that these communities experience more smoke exposures
in comparison to less vulnerable communities
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