Laboratory experiments of current collection to long conductors with geometries relevant to bare electrodynamic tethers

We describe chamber tests of simulated electrodynamic tethers (EDTs) of different geometries operating in a dense, high-speed plasma. The geometries tested and described here were cylindrical and flat-ribbon. Several important conclusions that can be drawn from the tests are as follows: the currents collected by cylinder are close to what would be predicted via orbital-motion-limited (OML) current collection theory. The tape tether had comparable current levels to a theoretical equal area OML cylinder collector. However, I-V behavior clearly is different at nearest distances ( ∼ 16λD∼16λD tape width) as compared to furthest test distances ( ∼ 6λD∼6λD tape width). The tape tether did better than a theoretical equal mass solid cylinder. A “knee” in the I-V curves can be seen in the tape data at a potential that is near the estimated energy of the incoming beam of ions, at least for the closest distances where Debye length is smallest. Below this knee the current increases rapidly as voltage is increased. Above the knee the current increases at a rate near that expected from OML current-collection models depending on the relative width. This likely is an example of high-speed plasma flow effect. Perpendicular tape orientation performed slightly better than parallel. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87700/2/517_1.pd

Ground simulations of electron current to wide probes for electrodynamic tethers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76486/1/AIAA-2001-3337-341.pd

Primate Energy eExpenditure and Life History

Humans and other primates are distinct among placental mammals in having exceptionally slow rates of growth, reproduction, and aging. Primates’ slow life history schedules are generally thought to reflect an evolved strategy of allocating energy away from growth and reproduction and toward somatic investment, particularly to the development and maintenance of large brains. Here we examine an alternative explanation: that primates’ slow life histories reflect low total energy expenditure (TEE) (kilocalories per day) relative to other placental mammals. We compared doubly labeled water measurements of TEE among 17 primate species with similar measures for other placental mammals. We found that primates use remarkably little energy each day, expending on average only 50% of the energy expected for a placental mammal of similar mass. Such large differences in TEE are not easily explained by differences in physical activity, and instead appear to reflect systemic metabolic adaptation for low energy expenditures in primates. Indeed, comparisons of wild and captive primate populations indicate similar levels of energy expenditure. Broad interspecific comparisons of growth, reproduction, and maximum life span indicate that primates’ slow metabolic rates contribute to their characteristically slow life histories

Inequalities' Impacts: State of the Art Review

By way of introduction This report provides the fi rm foundation for anchoring the research that will be performed by the GINI project. It subsequently considers the fi elds covered by each of the main work packages: ● inequalities of income, wealth and education, ● social impacts, ● political and cultural impacts, and ● policy effects on and of inequality. Though extensive this review does not pretend to be exhaustive. The review may be “light” in some respects and can be expanded when the analysis evolves. In each of the four fi elds a signifi cant number of discussion papers will be produced, in total well over 100. These will add to the state of the art while also covering new round and generating results that will be incorporated in the Analysis Reports to be prepared for the work packages. In that sense, the current review provides the starting point. At the same time, the existing body of knowledge is broader or deeper depending on the particular fi eld and its tradition of research. The very motivation of GINI’s focused study of the impacts of inequalities is that a systematic study is lacking and relatively little is known about those impacts. This also holds for the complex collection of, the effects that inequality can have on policy making and the contributions that policies can make to mitigating inequalities but also to enhancing them. By contrast, analyses of inequality itself are many, not least because there is a wide array of inequalities; inequalities have become more easily studied comparatively and much of that analysis has a signifi cant descriptive fl avour that includes an extensive discussion of measurement issues. @GINI hopes to go beyond that and cover the impacts of inequalities at the same time

Benefits of Empiric Nutritional and Medical Therapy for Semen Parameters and Pregnancy and Live Birth Rates in Couples with Idiopathic Infertility : A Systematic Review and Meta-analysis

The authors would like to thank Julie Darraugh and Karin Plass from the EAU Guidelines Office for their assistance with the systematic review.Peer reviewedPostprin

A Mouse-Adapted SARS-Coronavirus Causes Disease and Mortality in BALB/c Mice

No single animal model for severe acute respiratory syndrome (SARS) reproduces all aspects of the human disease. Young inbred mice support SARS-coronavirus (SARS-CoV) replication in the respiratory tract and are available in sufficient numbers for statistical evaluation. They are relatively inexpensive and easily accessible, but their use in SARS research is limited because they do not develop illness following infection. Older (12- to 14-mo-old) BALB/c mice develop clinical illness and pneumonitis, but they can be hard to procure, and immune senescence complicates pathogenesis studies. We adapted the SARS-CoV (Urbani strain) by serial passage in the respiratory tract of young BALB/c mice. Fifteen passages resulted in a virus (MA15) that is lethal for mice following intranasal inoculation. Lethality is preceded by rapid and high titer viral replication in lungs, viremia, and dissemination of virus to extrapulmonary sites accompanied by lymphopenia, neutrophilia, and pathological changes in the lungs. Abundant viral antigen is extensively distributed in bronchial epithelial cells and alveolar pneumocytes, and necrotic cellular debris is present in airways and alveoli, with only mild and focal pneumonitis. These observations suggest that mice infected with MA15 die from an overwhelming viral infection with extensive, virally mediated destruction of pneumocytes and ciliated epithelial cells. The MA15 virus has six coding mutations associated with adaptation and increased virulence; when introduced into a recombinant SARS-CoV, these mutations result in a highly virulent and lethal virus (rMA15), duplicating the phenotype of the biologically derived MA15 virus. Intranasal inoculation with MA15 reproduces many aspects of disease seen in severe human cases of SARS. The availability of the MA15 virus will enhance the use of the mouse model for SARS because infection with MA15 causes morbidity, mortality, and pulmonary pathology. This virus will be of value as a stringent challenge in evaluation of the efficacy of vaccines and antivirals

Climate-Induced Boreal Forest Change: Predictions versus Current Observations

For about three decades, there have been many predictions of the potential ecological response in boreal regions to the currently warmer conditions. In essence, a widespread, naturally occurring experiment has been conducted over time. In this paper, we describe previously modeled predictions of ecological change in boreal Alaska, Canada and Russia, and then we investigate potential evidence of current climate-induced change. For instance, ecological models have suggested that warming will induce the northern and upslope migration of the treeline and an alteration in the current mosaic structure of boreal forests. We present evidence of the migration of keystone ecosystems in the upland and lowland treeline of mountainous regions across southern Siberia. Ecological models have also predicted a moisture-stress-related dieback in white spruce trees in Alaska, and current investigations show that as temperatures increase, white spruce tree growth is declining. Additionally, it was suggested that increases in infestation and wildfire disturbance would be catalysts that precipitate the alteration of the current mosaic forest composition. In Siberia, five of the last seven years have resulted in extreme fire seasons, and extreme fire years have also been more frequent in both Alaska and Canada. In addition, Alaska has experienced extreme and geographically expansive multi-year outbreaks of the spruce beetle, which had been previously limited by the cold, moist environment. We suggest that there is substantial evidence throughout the circumboreal region to conclude that the biosphere within the boreal terrestrial environment has already responded to the transient effects of climate change. Additionally, temperature increases and warming-induced change are progressing faster than had been predicted in some regions, suggesting a potential non-linear rapid response to changes in climate, as opposed to the predicted slow linear response to climate change

Whole-Genome Sequencing of Individuals from a Founder Population Identifies Candidate Genes for Asthma

Asthma is a complex genetic disease caused by a combination of genetic and environmental risk factors. We sought to test classes of genetic variants largely missed by genome-wide association studies (GWAS), including copy number variants (CNVs) and low-frequency variants, by performing whole-genome sequencing (WGS) on 16 individuals from asthma-enriched and asthma-depleted families. The samples were obtained from an extended 13-generation Hutterite pedigree with reduced genetic heterogeneity due to a small founding gene pool and reduced environmental heterogeneity as a result of a communal lifestyle. We sequenced each individual to an average depth of 13-fold, generated a comprehensive catalog of genetic variants, and tested the most severe mutations for association with asthma. We identified and validated 1960 CNVs, 19 nonsense or splice-site single nucleotide variants (SNVs), and 18 insertions or deletions that were out of frame. As follow-up, we performed targeted sequencing of 16 genes in 837 cases and 540 controls of Puerto Rican ancestry and found that controls carry a significantly higher burden of mutations in IL27RA (2.0% of controls; 0.23% of cases; nominal p = 0.004; Bonferroni p = 0.21). We also genotyped 593 CNVs in 1199 Hutterite individuals. We identified a nominally significant association (p = 0.03; Odds ratio (OR) = 3.13) between a 6 kbp deletion in an intron of NEDD4L and increased risk of asthma. We genotyped this deletion in an additional 4787 non-Hutterite individuals (nominal p = 0.056; OR = 1.69). NEDD4L is expressed in bronchial epithelial cells, and conditional knockout of this gene in the lung in mice leads to severe inflammation and mucus accumulation. Our study represents one of the early instances of applying WGS to complex disease with a large environmental component and demonstrates how WGS can identify risk variants, including CNVs and low-frequency variants, largely untested in GWAS