51 research outputs found

    Infrared enhanced analytic coupling and chiral symmetry breaking in QCD

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    We study the impact on chiral symmetry breaking of a recently developed model for the QCD analytic invariant charge. This charge contains no adjustable parameters, other than the QCD mass scale Λ\Lambda, and embodies asymptotic freedom and infrared enhancement into a single expression. Its incorporation into the standard form of the quark gap equation gives rise to solutions for the dynamically generated mass that display a singular confining behaviour at the origin. Using the Pagels-Stokar method we relate the obtained solutions to the pion decay constant fπf_{\pi}, and estimate the scale parameter Λ\Lambda, in the presence of four active quarks, to be about 880 MeV.Comment: 14 pages, 3 figures; to appear in J. Phys.

    Occupational asphalt is not associated with head and neck cancer

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    Epidemiologic studies that evaluate the relationship between occupational asphalt exposure and head and neck cancer have had a limited ability to control for known risk factors such as smoking, alcohol and human papillomavirus (HPV)

    Supersymmetric Extra Dimensions: Gravitino Effects in Selectron Pair Production

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    We examine the phenomenological consequences of a supersymmetric bulk in the scenario of large extra dimensions. We assume supersymmetry is realized in the bulk and study the interactions of the resulting bulk gravitino Kaluza-Klein (KK) tower of states, with supersymmetry breaking on the brane inducing a light mass for the zero-mode gravitino. We derive the 4-d effective theory, including the couplings of the bulk gravitino KK states to fermions and their scalar superpartners. The virtual exchange of the gravitino KK states in selectron pair production in polarized \epem collisions is then examined. We find that the leading order operator for this exchange is dimension six, in contrast to that of bulk graviton KK exchange which induces a dimension eight operator at lowest order. The resulting kinematic distributions for selectron production are dramatically altered from those in D=4 supersymmetric scenarios, and can lead to a enormous sensitivity to the fundamental higher dimensional Planck scale, of order 2025×s20-25\times \sqrt s.Comment: 48 pg

    Environmental liability litigation could remedy biodiversity loss

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    Abstract: Many countries allow lawsuits to hold responsible parties liable for the environmental harm they cause. Such litigation remains largely untested in most biodiversity hotspots and is rarely used in response to leading drivers of biodiversity loss, including illegal wildlife trade. Yet, liability litigation is a potentially ground‐breaking conservation strategy to remedy harm to biodiversity by seeking legal remedies such as species rehabilitation, public apologies, habitat conservation and education, with the goal of making the injured parties ‘whole’. However, precedent cases, expert guidance, and experience to build such conservation lawsuits is nascent in most countries. We propose a simplified framework for developing conservation lawsuits across countries and conservation contexts. We explain liability litigation in terms of three dimensions: (1) defining the harm that occurred, (2) identifying appropriate remedies to that harm, and (3) understanding what remedies the law and courts will allow. We illustrate the framework via a hypothetical lawsuit against an illegal orangutan trader in Indonesia. We highlight that conservationists’ expertise is essential to characterizing harm and identifying remedies, and could more actively contribute to strategic, science‐based litigation. This would identify priority contexts, target defendants responsible for egregious harm, propose novel and meaningful remedies, and build new transdisciplinary collaborations

    Male-Specific Transfer and Fine Scale Spatial Differences of Newly Identified Cuticular Hydrocarbons and Triacylglycerides in a Drosophila Species Pair

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    We analyzed epicuticular hydrocarbon variation in geographically isolated populations of D. mojavensis cultured on different rearing substrates and a sibling species, D. arizonae, with ultraviolet laser desorption/ionization mass spectrometry (UV-LDI MS). Different body parts, i.e. legs, proboscis, and abdomens, of both species showed qualitatively similar hydrocarbon profiles consisting mainly of long-chain monoenes, dienes, trienes, and tetraenes. However, D. arizonae had higher amounts of most hydrocarbons than D. mojavensis and females of both species exhibited greater hydrocarbon amounts than males. Hydrocarbon profiles of D. mojavensis populations were significantly influenced by sex and rearing substrates, and differed between body parts. Lab food–reared flies had lower amounts of most hydrocarbons than flies reared on fermenting cactus substrates. We discovered 48 male- and species-specific hydrocarbons ranging in size from C22 to C50 in the male anogenital region of both species, most not described before. These included several oxygen-containing hydrocarbons in addition to high intensity signals corresponding to putative triacylglycerides, amounts of which were influenced by larval rearing substrates. Some of these compounds were transferred to female cuticles in high amounts during copulation. This is the first study showing that triacylglycerides may be a separate class of courtship-related signaling molecules in drosophilids. This study also extends the kind and number of epicuticular hydrocarbons in these species and emphasizes the role of larval ecology in influencing amounts of these compounds, many of which mediate courtship success within and between species

    Knowledge, attitudes, and practices of pregnant women regarding COVID-19 vaccination in pregnancy in 7 low- and middle-income countries: An observational trial from the Global Network for Women and Children’s Health Research

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    Objectives: We sought to determine the knowledge, attitudes and practices of pregnant women regarding COVID-19 vaccination in pregnancy in seven low- and middle-income countries (LMIC). Design: Prospective, observational, population-based study. Settings: Study areas in seven LMICs: Bangladesh, India, Pakistan, Guatemala, Democratic Republic of the Congo (DRC), Kenya and Zambia. Population: Pregnant women in an ongoing registry. Methods: COVID-19 vaccine questionnaires were administered to pregnant women in the Global Network's Maternal Newborn Health Registry from February 2021 through November 2021 in face-to-face interviews. Main outcome measures: Knowledge, attitude and practice regarding vaccination during pregnancy; vaccination status. Results: No women were vaccinated except for small proportions in India (12.9%) and Guatemala (5.5%). Overall, nearly half the women believed the COVID-19 vaccine is very/somewhat effective and a similar proportion believed that the COVID-19 vaccine is safe for pregnant women. With availability of vaccines, about 56.7% said they would get the vaccine and a 34.8% would refuse. Of those who would not get vaccinated, safety, fear of adverse effects, and lack of trust predicted vaccine refusal. Those with lower educational status were less willing to be vaccinated. Family members and health professionals were the most trusted source of information for vaccination. Conclusions: This COVID-19 vaccine survey in seven LMICs found that knowledge about the effectiveness and safety of the vaccine was generally low but varied. Concerns about vaccine safety and effectiveness among pregnant women is an important target for educational efforts to increase vaccination rates

    Determinants and Effects on Property Values of Participation in Voluntary Cleanup Programs: The Case of Colorado

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    State Voluntary Cleanup Programs (VCPs) were established starting in the 1990s to encourage the environmental remediation and redevelopment of contaminated properties. These programs typically offer liability relief, subsidies and other regulatory incentives in exchange for site cleanup. This paper asks three questions: First, what type of properties are attracted to voluntary cleanup programs? Second, what is the interaction between these state programs and other incentives for remediation and economic development, such as Enterprise Zone and Brownfield Zone designations? Third, what is the effect of participation in the VCP on property values? We use data from Colorado’s VCP to answer these questions. We find that most of the properties enrolled in this program were not previously listed on EPA’s contaminated site registries, and that most applicants seek to obtain directly a “no further action” determination without undergoing remediation. The main determinants of participation are the size of the parcel and whether the surrounding land use is primarily residential, while other incentives have little effect. Properties with confirmed contamination sell at a 47% discount relative to comparable uncontaminated parcels, and participation tends to raise the property price, but this latter effect is not statistically significant. Taken together, these findings suggest that the participating properties are those with high development potential, and hint at the possibility that owners or developers may be seeking to obtain a clean bill of health from the State with only minimal or no cleanup efforts. Were these findings confirmed with data from other states, they would raise doubts about the effectiveness of voluntary programs in encouraging remediation and their usefulness in reversing some of the undesired effects of the Superfund legislation

    Occupational asphalt is not associated with head and neck cancer

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    BACKGROUND: Epidemiologic studies that evaluate the relationship between occupational asphalt exposure and head and neck cancer have had a limited ability to control for known risk factors such as smoking, alcohol and human papillomavirus (HPV). AIMS: To better elucidate this relationship by including known risk factors in a large case–control study of head and neck squamous cell carcinoma (HNSCC) from the greater Boston area. METHODS: We analysed the relationship between occupational asphalt exposure and HNSCC among men in the Greater Boston area of Massachusetts. Analyses were conducted using unconditional multivariable logistic regression, performed with adjustments for age, race, education, smoking, alcohol consumption and HPV serology. RESULTS: There were 753 cases and 913 controls. No associations between HNSCC and occupational asphalt exposure (neither among ever-exposed nor by occupational duration) were observed for exposures in any occupation or those restricted to the construction industry. We also observed no associations in subgroup analyses of never-smokers and ever-smokers. Adjusting for known risk factors further reduced the estimated effect of asphalt exposure on HNSCC risk. CONCLUSIONS: We found no evidence for an association between occupational asphalt exposure and HNSCC. The null findings from this well-controlled analysis could suggest that the risk estimates stemming from occupational cohort studies may be overestimated due to uncontrolled confounding and enhance the literature available for weighing cancer risk from occupational exposure to bitumen
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