2,611 research outputs found
The marginal costs of different greenhouse gases: an application of FUND
The authors use FUND 3.9 to estimate the social cost of four greenhouse gases—carbon dioxide, methane, nitrous oxide, and sulphur hexafluoride—with sensitivity tests for carbon dioxide fertilization, terrestrial feedbacks, climate sensitivity, discounting, equity weighting, and socioeconomic and emissions assumptions. They also estimate the global damage potential for each gas—the ratio of the social cost of the non-carbon dioxide greenhouse gas to the social cost of carbon dioxide. For all gases, they find the social costs and damage potentials sensitive to alternative assumptions. The global damage potentials are compared to global warming potentials (GWPs), a key metric used to compare gases. The authors find that global damage potentials are higher than GWPs in nearly all sensitivities. This finding suggests that previous papers using GWPs may be underestimating the relative importance of reducing noncarbon dioxide greenhouse gas emissions from a climate damage perspective. Of particular interest is the sensitivity of results to carbon dioxide fertilization, which notably reduces the social cost of carbon dioxide, but only has a small effect on the other gases. As a result, the global damage potentials for methane and nitrous oxide are much higher with carbon dioxide fertilization included, and higher than many previous estimates
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Platform dependence of inference on gene-wise and gene-set involvement in human lung development
<p>Abstract</p> <p>Background</p> <p>With the recent development of microarray technologies, the comparability of gene expression data obtained from different platforms poses an important problem. We evaluated two widely used platforms, Affymetrix U133 Plus 2.0 and the Illumina HumanRef-8 v2 Expression Bead Chips, for comparability in a biological system in which changes may be subtle, namely fetal lung tissue as a function of gestational age.</p> <p>Results</p> <p>We performed the comparison via sequence-based probe matching between the two platforms. "Significance grouping" was defined as a measure of comparability. Using both expression correlation and significance grouping as measures of comparability, we demonstrated that despite overall cross-platform differences at the single gene level, increased correlation between the two platforms was found in genes with higher expression level, higher probe overlap, and lower p-value. We also demonstrated that biological function as determined via KEGG pathways or GO categories is more consistent across platforms than single gene analysis.</p> <p>Conclusion</p> <p>We conclude that while the comparability of the platforms at the single gene level may be increased by increasing sample size, they are highly comparable ontologically even for subtle differences in a relatively small sample size. Biologically relevant inference should therefore be reproducible across laboratories using different platforms.</p
Dietary Fiber, Lung Function, and Chronic Obstructive Pulmonary Disease in the Atherosclerosis Risk in Communities Study
Recent data suggest beneficial effects of fiber intake on chronic respiratory symptoms in adults that are independent of antioxidant vitamin intake, but little is known about fiber consumption in relation to lung function and chronic obstructive pulmonary disease (COPD). The authors investigated the association of fiber intake with lung function and COPD in 11,897 men and women from the Atherosclerosis Risk in Communities (ARIC) study. After controlling for potential confounders, positive associations between lung function and fiber intake from all sources as well as from cereal or fruit alone were found. Participants in the highest quintile of total fiber intake had 60.2 ml higher forced expiratory volume in 1 second (FEV1) (p for trend<0.001), 55.2 ml higher forced vital capacity (FVC) (p=0.001), 0.4% higher FEV1/FVC ratio (p=0.040), 1.8% higher percent predicted FEV1 (p<0.001), and 1.4% higher percent predicted FVC (p=0.001), compared with those in the lowest quintile. The adjusted odds ratios of COPD for the highest versus lowest quintiles of intake were 0.85 (p=0.044) for total fiber, 0.83 (p=0.021) for cereal fiber, and 0.72 (p=0.005) for fruit fiber. This study provides the first evidence that dietary fiber is independently associated with better lung function and reduced prevalence of COPD
Homology-based annotation of non-coding RNAs in the genomes of Schistosoma mansoni and Schistosoma japonicum
<p>Abstract</p> <p>Background</p> <p>Schistosomes are trematode parasites of the phylum Platyhelminthes. They are considered the most important of the human helminth parasites in terms of morbidity and mortality. Draft genome sequences are now available for <it>Schistosoma mansoni </it>and <it>Schistosoma japonicum</it>. Non-coding RNA (ncRNA) plays a crucial role in gene expression regulation, cellular function and defense, homeostasis, and pathogenesis. The genome-wide annotation of ncRNAs is a non-trivial task unless well-annotated genomes of closely related species are already available.</p> <p>Results</p> <p>A homology search for structured ncRNA in the genome of <it>S. mansoni </it>resulted in 23 types of ncRNAs with conserved primary and secondary structure. Among these, we identified rRNA, snRNA, SL RNA, SRP, tRNAs and RNase P, and also possibly MRP and 7SK RNAs. In addition, we confirmed five miRNAs that have recently been reported in <it>S. japonicum </it>and found two additional homologs of known miRNAs. The tRNA complement of <it>S. mansoni </it>is comparable to that of the free-living planarian <it>Schmidtea mediterranea</it>, although for some amino acids differences of more than a factor of two are observed: Leu, Ser, and His are overrepresented, while Cys, Meth, and Ile are underrepresented in <it>S. mansoni</it>. On the other hand, the number of tRNAs in the genome of <it>S. japonicum </it>is reduced by more than a factor of four. Both schistosomes have a complete set of minor spliceosomal snRNAs. Several ncRNAs that are expected to exist in the <it>S. mansoni </it>genome were not found, among them the telomerase RNA, vault RNAs, and Y RNAs.</p> <p>Conclusion</p> <p>The ncRNA sequences and structures presented here represent the most complete dataset of ncRNA from any lophotrochozoan reported so far. This data set provides an important reference for further analysis of the genomes of schistosomes and indeed eukaryotic genomes at large.</p
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Glass ceilings and stone floors: an intersectional approach to challenges UK geographers face across the career lifecycle
While there has been a steady growth of women working in geography in UK universities since the mid-Twentieth Century, there are continuing challenges in gendered career progression and professional interactions within the contemporary discipline. These range from problems associated with employment precarity and inflexible work practices, life choices and obligations in the domestic arena, discrimination and bullying, to less tangible gendered norms and cultures in the workplace. This paper discusses these challenges and inequalities in the light of a brief overview of sector-wide statistical data on appointments by gender and career-stage and with the analysis of some 250 in-depth responses to a nationwide qualitative survey of gender and career experience in UK universities (Maddrell et al 2016). While the term ‘glass ceiling’ still has significant relevance, findings show a more complicated picture which also includes ‘stone floors’ and stumbling blocks. It also shows how career experience varies by institution and individual: challenges in career progression can be compounded by institutional protocols and intersectional factors, and vary with career stage. The intersection of early-career job precarity, reproductive decisions and associated family responsibilities were particularly highlighted in this study. These ‘pinch points’ in career development disproportionately affect, but are not limited to, female early career scholars. Early career progress may be stalled in mid-career in multi-staged promotional systems such as that in UK universities; some from minorities face compound barriers; men with caring responsibilities may face prejudice. The paper concludes with suggested strategies for change, highlighting the importance of individual university and department protocols and practices; line manager and other senior colleagues’ attitudes and leadership in creating workplaces with an equality-driven ethos and structures that allow individuals to flourish
Prospective Analysis of Traffic Exposure as a Risk Factor for Incident Coronary Heart Disease: The Atherosclerosis Risk in Communities (ARIC) Study
BackgroundFor people living close to busy roads, traffic is a major source of air pollution. Few prospective data have been published on the effects of long-term exposure to traffic on the incidence of coronary heart disease (CHD).ObjectivesIn this article, we examined the association between long-term traffic exposure and incidence of fatal and nonfatal CHD in a population-based prospective cohort study.MethodsWe studied 13,309 middle-age men and women in the Atherosclerosis Risk in Communities study, without previous CHD at enrollment, from 1987 to 1989 in four U.S. communities. Geographic information system–mapped traffic density and distance to major roads served as measures of traffic exposure. We examined the association between traffic exposure and incident CHD using proportional hazards regression models, with adjustment for background air pollution and a wide range of individual cardiovascular risk factors.ResultsOver an average of 13 years of follow-up, 976 subjects developed CHD. Relative to those in the lowest quartile of traffic density, the adjusted hazard ratio (HR) in the highest quartile was 1.32 [95% confidence interval (CI), 1.06–1.65; p-value for trend across quartiles = 0.042]. When we treated traffic density as a continuous variable, the adjusted HR per one unit increase of log-transformed density was 1.03 (95% CI, 1.01–1.05; p = 0.006). For residents living within 300 m of major roads compared with those living farther away, the adjusted HR was 1.12 (95% CI, 0.95–1.32; p = 0.189). We found little evidence of effect modification for sex, smoking status, obesity, low-density lipoprotein cholesterol level, hypertension, age, or education.ConclusionHigher long-term exposure to traffic is associated with incidence of CHD, independent of other risk factors. These prospective data support an effect of traffic-related air pollution on the development of CHD in middle-age persons
Agent-Based Modeling Approach for Developing Enforcement Mechanisms in Spectrum Sharing Scenarios: An Application for the 1695-1710mhz Band
As radio spectrum sharing matures, one of the main challenges becomes finding adequate governance systems and the appropriate enforcement mechanisms. Historically, these processes were assigned to a central entity (in most cases a governmental agency). Nevertheless, the literature of Common Pool Resources (CPRs) shows that other governance mechanisms are possible, which include collaboration with a private, third-party regulator or the complete absence of central institutions, as in self-enforcement solutions. These alternatives have been developed around well-known CPRs such as fisheries, forests, etc. As argued by Weiss et al, and other researchers, spectrum can indeed be considered to be a CPR. In this work, we study the two extremes of governance systems that could be applied to spectrum sharing scenarios. Initially, we study the classical centralized scheme of command and control, where governmental institutions are in charge of rule-definition and enforcement. Subsequently, we explore a government-less environment, i.e., a distributed enforcement approach. In this anarchy situation (i.e., lack of a formal government intervention as defined by Leeson), rules and enforcement mechanisms are solely the product of repeated interactions among the intervening agents. For our analysis, we have selected the spectrum sharing framework of the 1695-1710MHz band. We also use the definitions presented by Bhattarai as well as Altamimi for managing the size of the coordination and exclusion zones. In addition, we utilize Agent-Based Modelling (ABM) to analyze the applicability of these governance mechanisms. ABM simulation allows us to explore how macro phenomena can emerge from micro-level interactions of independent agents
Development of a non-human primate BCG infection model for the evaluation of candidate tuberculosis vaccines.
The lack of validated immunological correlates of protection makes tuberculosis vaccine development difficult and expensive. Using intradermal bacille Calmette-Guréin (BCG) as a surrogate for aerosol Mycobacterium tuberculosis (M.tb) in a controlled human infection model could facilitate vaccine development, but such a model requires preclinical validation. Non-human primates (NHPs) may provide the best model in which to do this. Cynomolgus and rhesus macaques were infected with BCG by intradermal injection. BCG was quantified from a skin biopsy of the infection site and from draining axillary lymph nodes, by culture on solid agar and quantitative polymerase chain reaction. BCG was detected up to 28 days post-infection, with higher amounts of BCG detected in lymph nodes after high dose compared to standard dose infection. Quantifying BCG from lymph nodes of cynomolgus macaques 14 days post-high dose infection showed a significant reduction in the amount of BCG detected in the BCG-vaccinated compared to BCG-naïve animals. Demonstrating a detectable vaccine effect in the lymph nodes of cynomolgus macaques, which is similar in magnitude to that seen in an aerosol M.tb infection model, provides support for proof-of-concept of an intradermal BCG infection model and evidence to support the further evaluation of a human BCG infection model
Agent-Based Modelling Approach for Developing Enforcement Mechanisms in Spectrum Sharing Scenarios: An application for the 1695-1710MHz band
As radio spectrum sharing matures, one of the main challenges becomes finding adequate governance systems and the appropriate enforcement mechanisms. Historically, these processes were assigned to a central entity (in most cases a governmental agency). Nevertheless, the literature of Common Pool Resources (CPRs) shows that other governance mechanisms are possible, which include collaboration with a private, thirdparty regulator or the complete absence of central institutions, as in self-enforcement solutions. These alternatives have been developed around well-known CPRs such as fisheries, forests, etc. As argued by Weiss et al [50], and other researchers, spectrum can indeed be considered to be a CPR. In this work we study the two extremes of governance systems that could be applied to spectrum sharing scenarios. Initially, we study the classical centralized scheme of command and control, where governmental institutions are in charge of rule-definition and enforcement. Subsequently, we explore a government-less environment, i.e., a distributed enforcement approach. In this anarchy situation (i.e., lack of a formal government intervention as defined by Leeson [29]), rules and enforcement mechanisms are solely the product of repeated interactions among the intervening agents. For our analysis, we have selected the spectrum sharing framework of the 1695-1710MHz band. We also use the definitions presented by Bhattarai et al. [9], [10] as well as Altamimi [3] for managing the size of the coordination and exclusion zones. In addition, we utilize Agent-Based Modelling (ABM) to analyze the applicability of these governance mechanisms. ABM simulation allows us to explore how macro phenomena can emerge from micro-level interactions of independent agents
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