Medical Implications of Space Radiation Exposure Due to Low Altitude Polar Orbits

Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and Solar Particle Events may pose a critical health risk to future spaceflight crews and can have a serious impact to all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960's Manned Orbiting Laboratory program's space vehicle and the high inclination polar orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-day mission using high performance, multi-core computers. Projected doses from a historically large SPE (e.g. the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies.It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.Comment: 6 pages, 4 figures, 2 table

U.S. banks, competition, and the Mexican banking system: how much will NAFTA matter?

Bank competition ; North American Free Trade Agreement ; Mexico

'Climate Response Functions' for the Arctic Ocean: a proposedcoordinated modeling experiment

A coordinated set of Arctic modelling experiments, which explore how the Arctic responds to changes in external forcing, is proposed. Our goal is to compute and compare “climate response functions” (CRFs) – the transient response of key observable indicators such as sea-ice extent, freshwater content of the Beaufort Gyre, etc. – to abrupt “step” changes in forcing fields across a number of Arctic models. Changes in wind, freshwater sources, and inflows to the Arctic basin are considered. Convolutions of known or postulated time series of these forcing fields with their respective CRFs then yield the (linear) response of these observables. This allows the project to inform, and interface directly with, Arctic observations and observers and the climate change community. Here we outline the rationale behind such experiments and illustrate our approach in the context of a coarse-resolution model of the Arctic based on the MITgcm. We conclude by summarizing the expected benefits of such an activity and encourage other modelling groups to compute CRFs with their own models so that we might begin to document their robustness to model formulation, resolution, and parameterization.National Science Foundation (U.S.) (Award 1603557

Estimating Peak Demand for Beach Parking Spaces

The United States Army Corps of Engineers planning guidance stipulates that in order for local beach communities to qualify for Federal cost share funds for Hurricane and Storm Damage Reduction beach renourishment projects, the community must provide public beach access and parking to satisfy peak demand. This study presents a method for estimating peak demand for beach parking spaces in the presence of parking constraints. A Tobit regression model is developed to estimate the number of parking spaces that would be necessary to meet unconstrained demand on a given percentage of peak demand days. For example, the model can be used to estimate the number of parking spaces that would be adequate to meet peak demand on 90% of peak parking days. The Tobit model provides a promising framework for estimating peak parking demand under constrained parking conditions, a situation that characterizes most beach communities.

Emerging Methods for the Study of Coastal Ecosystem Landscape Structure and Change

An introduction is presented in which the editor discusses various remote-sensing approaches to improve knowledge for studying changes in coastal ecosystem landscape

Synthesis and characterization of two oxo-bridged oxo(arylimido) [tris(3,5-dimethylpyrazolyI)borato]molybdenum(V) complexes and crystal structure of [MoTp*(O)CI](μ-O)[MoTp*(CI)(≡NC6H 4OMe)]

Reaction of the oxo-molybdenum(V) compound, [MoTp*(O)Cl2], [Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate] with p-methoxy and p-nitroaniline in the presence of Et3N under N2, afforded the oxo-bridged oxo(arylimido) molybdenum(V) complexes, [MoTp*(O)Cl](μ- O)[MoTp*(Cl)(≡NC6H4R)] (1, R = OMe; 2, R = NO2). The new compounds were characterized by elemental analysis, i.r., mass, and 1H-n.m.r. spectra. The single crystal X-ray crystallographic determination of [MoTp*(O)Cl](μ-O)[MoTp*(Cl) (≡NC6H4OMe)] was carried out to confirm that there is a Mo - O - Mo bridge and a near linear arylimido group in the structure.TÜBİTA

Impact of Burkholderia Infection on Lung Transplantation in Cystic Fibrosis

Rationale: Lung transplantation offers the only survival option for patients with cystic fibrosis (CF) with end-stage pulmonary disease. Infection with Burkholderia species is typically considered a contraindication to transplantation in CF. However, the risks posed by different Burkholderia species on transplantation outcomes are poorly defined. Objectives: To quantify the risks of infection with Burkholderia species on survival before and after lung transplantation in patients with CF. Methods: Multivariate Cox survival models assessed hazard ratios of infection with Burkholderia species in 1,026 lung transplant candidates and 528 lung transplant recipients. Lung allocation scores, incorporating Burkholderia infection status, were calculated for transplant candidates. Measurements and Main Results: Transplant candidates infected with different Burkholderia species did not have statistically different mortality rates. Among transplant recipients infected with B. cenocepacia, only those infected with nonepidemic strains had significantly greater post-transplant mortality compared with uninfected patients (hazard ratio [HR], 2.52; 95% confidence interval [CI], 1.04–6.12; P 5 0.04). Hazards were similar between uninfected transplant recipients and those infected with B. multivorans (HR, 0.66; 95% CI, 0.27–1.56; P 5 0.34). Transplant recipients infected with B. gladioli had significantly greater post-transplant mortality than uninfected patients (HR, 2.23; 95% CI, 1.05–4.74; P 5 0.04). Oncehazards for species/strainwereincluded,lung allocation scores of B. multivorans–infected transplant candidates were comparable to uninfected candidate scores, whereas those of candidates infected with nonepidemic B. cenocepacia or B. gladioli were lower. Conclusions: Post-transplant mortality among patients with CF infected with Burkholderia varies by infecting species. This variability should be taken into account in evaluating lung transplantation candidates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91898/1/Murray LiPuma AJRCCM 2008.pd

Minding the Terrazzo Gap between Athletes and Nonathletes: Representativeness, Integration, and Academic Performance at the U.S. Air Force Academy

The tension between focusing on collegiate athletic or academic performance has persisted for decades. A recent study finds that recruited athletes in college athletic programs underperform academically, earning lower grades than predicted. It postulates that increased representativeness and integration efforts will enhance the academic value of college athletes’ experience. The U.S. Air Force Academy system presents a natural experiment of whether such efforts can affect student-athlete academic performance. In this setting, we find that student-athletes perform comparably to nonathletes after controlling for predicted academic performance

Transaction Costs in Payment of Environmental Service Contracts

Citation: Jeffrey M. Peterson, Craig M. Smith, John C. Leatherman, Nathan P. Hendricks, John A. Fox; Transaction Costs in Payment for Environmental Service Contracts, American Journal of Agricultural Economics, Volume 97, Issue 1, 1 January 2015, Pages 219–238, https://doi.org/10.1093/ajae/aau071Payment for environmental service contracts commonly require actions beyond adoption of a practice, such as undergoing specified enrollment procedures, granting consent to being monitored, and paying penalties for violations. These provisions are a bundle of attributes a landholder must accept with contract enrollment, leading to transaction costs in the contracting process. This article develops a principal–agent framework to study the links between these transaction costs and the well-known information asymmetries between the landholders and the government agency offering contracts. Using stated choice data collected from a sample of farmers, we estimate a mixed logit model to quantify the contribution of different contract attributes on contract willingness-to-accept (WTA). More stringent provisions in contracts were found to raise individual WTA by widely differing amounts across farmers, but the average effects imply that overall contract supply is sensitive to stringency. From a series of microsimulations based on the estimated model, we find that transaction costs create a significant drain on the cost-effectiveness of contracting from the agency’s point of view, similar in magnitude to the inefficiency created by hidden information. Although stringent contractual terms raise program expenditures, they may be justified if they raise compliance rates enough to offset the added cost. We also simulate an implicit frontier to trace out the change in compliance needed to justify a given increase in stringency. For environmental benefits in the range of previous estimates, this analysis suggests that stringent terms would need to substantially raise compliance rates to be cost effective