Factors Affecting New Firm Success and Their Use in Venture Capital Financing

Using a nationwide sample of 14,424 new firms, we find that attractive human capital traits at business entry for entrepreneurs include high educational attainment, owners who lie in the middle of—as opposed to the tails of—the age distribution, and family business background. Attractive firm traits are purchase of an existing firm rather than starting a firm de novo, and larger amounts of starting capital. Recent research has found that certain ethnic minorities are differentially restricted from obtaining commercial bank financing. Our statistical tests indicate that when we control for differences in human capital and firm traits, the venture capital market also differentially restricts minority entrepreneurs from obtaining venture capital. Thus public policy seeking to reduce the resulting financing gap for minority entrepreneurs may have economic justification. Except for the ethnic trait, the venture capital market’s use of owner and firm information is consistent with selecting those firms which have more survival potential

The Emergence and Future of Near-Surface Geophysics

Over the past 30 years, geophysical methods have assumed a much more prominent and integral role in many investigations where subsurface features have environmental and engineering importance. In fact, the field once referred to as environmental and engineering geophysics has broadened to include other applications (e.g., archeology, forensics), and is now commonly referred to more generally as near-surface geophysics. It is difficult to precisely define near-surface geophysics, and the definition will likely depend on whom you ask. However, we define it as the use of geophysical methods to investigate the zone between the surface and hundreds of meters into the Earth\u27s crust. Applications include, but are not limited to, potable water management, engineered infrastructure and construction, site clearance, gas storage, natural-hazard mitigation, mining, forensics, and archaeology. Although the same physical principles are relevant for any target depth, the high degree of near-surface heterogeneity, rapid change in physical properties, and proximity to the free surface often dictates that dominant processes and therefore key assumptions differ between the near-surface and deeper investigations. While near-surface geophysics shares many technical and cultural attributes of oil and gas exploration, the majority of near-surface geophysicists practice under different economic drivers and conditions

Afriflu2—Second international workshop on influenza vaccination in the African continent—8 November 2012, Cape Town (South Africa)

AbstractThe second meeting of the Afriflu conferences took place in Cape Town, South Africa, with over 60 participants from 15 countries in Africa and also outside the continent. Significant progress in surveillance has been made in better understanding the illness burden of influenza on the continent, which limited evidence suggests is greater than that in the developed world. In southern Africa HIV and TB coinfections play a major role in increasing hospitalisation and mortality, while elsewhere in Africa other cofactors still need to be determined.There is currently no indigenous vaccine production in sub-Saharan Africa and only one facility, based in South Africa, capable of filling imported bulk. Innovative vaccine strategies will need to be explored, such as maternal immunisation, and also the possibility of other influenza vaccine options, such as live attenuated influenza vaccine for young children. Sustained indigenous vaccine production is essential for the continent to have vaccine security in the event of a pandemic even though establishing local production faces considerable challenges especially ensuring adequate markets on the continent. There is an urgent need to develop effective communication messages for decision makers as well as healthcare workers addressing the importance of influenza even in the face of the major competing health burdens of the continent

BMQ

BMQ: Boston Medical Quarterly was published from 1950-1966 by the Boston University School of Medicine and the Massachusetts Memorial Hospitals

The Far-Ultraviolet Spectrum and Short Timescale Variability of AM Herculis from Observations with the Hopkins Ultraviolet Telescope

Using the Hopkins Ultraviolet Telescope (HUT), we have obtained 850-1850 angstrom spectra of the magnetic cataclysmic variable star AM Her in the high state. These observations provide high time resolution spectra of AM Her in the FUV and sample much of the orbital period of the system. The spectra are not well-modelled in terms of simple white dwarf (WD) atmospheres, especially at wavelengths shortward of Lyman alpha. The continuum flux changes by a factor of 2 near the Lyman limit as a function of orbital phase; the peak fluxes are observed near magnetic phase 0.6 when the accreting pole of the WD is most clearly visible. The spectrum of the hotspot can be modelled in terms of a 100 000 K WD atmosphere covering 2% of the WD surface. The high time resolution of the HUT data allows an analysis of the short term variability and shows the UV luminosity to change by as much as 50% on timescales as short as 10 s. This rapid variability is shown to be inconsistent with the clumpy accretion model proposed to account for the soft X-ray excess in polars. We see an increase in narrow line emission during these flares when the heated face of the secondary is in view. The He II narrow line flux is partially eclipsed at secondary conjunction, implying that the inclination of the system is greater than 45 degrees. We also present results from models of the heated face of the secondary. These models show that reprocessing on the face of the secondary star of X-ray/EUV emission from the accretion region near the WD can account for the intensities and kinematics of most of the narrow line components observed.Comment: 19 pp., 12 fig., 3 tbl. To appear in The Astrophysical Journal. Also available at http://greeley.pha.jhu.edu/papers/amherpp.ps.g

Particulate-Matter Emission Estimates from Agricultural Spring-Tillage Operations Using LIDAR and Inverse Modeling

Particulate-matter (PM) emissions from a typical spring agricultural tillage sequence and a strip–till conservation tillage sequence in California’s San Joaquin Valley were estimated to calculate the emissions control efficiency (η) of the strip–till conservation management practice (CMP). Filter-based PM samplers, PM-calibrated optical particle counters (OPCs), and a PM-calibrated light detection and ranging (LIDAR) system were used to monitored upwind and downwind PM concentrations during May and June 2008. Emission rates were estimated through inverse modeling coupled with the filter and OPC measurements and through applying a mass balance to the PM concentrations derived from LIDAR data. Sampling irregularities and errors prevented the estimation of emissions from 42% of the sample periods based on filter samples. OPC and LIDAR datasets were sufficiently complete to estimate emissions and the strip–till CMP η, which were ∼90% for all size fractions in both datasets. Tillage time was also reduced by 84%. Calculated emissions for some operations were within the range of values found in published studies, while other estimates were significantly higher than literature values. The results demonstrate that both PM emissions and tillage time may be reduced by an order of magnitude through the use of a strip–till conservation tillage CMP when compared to spring tillage activities

X-rays Studies of the Solar System

X-ray observatories contribute fundamental advances in Solar System studies by probing Sun-object interactions, developing planet and satellite surface composition maps, probing global magnetospheric dynamics, and tracking astrochemical reactions. Despite these crucial results, the technological limitations of current X-ray instruments hinder the overall scope and impact for broader scientific application of X-ray observations both now and in the coming decade. Implementation of modern advances in X-ray optics will provide improvements in effective area, spatial resolution, and spectral resolution for future instruments. These improvements will usher in a truly transformative era of Solar System science through the study of X-ray emission.Comment: White paper submitted to Astro2020, the Astronomy and Astrophysics Decadal Surve

Differential transcriptomic responses to heat stress in surface and subterranean diving beetles

Subterranean habitats are generally very stable environments, and as such evolutionary transitions of organisms from surface to subterranean lifestyles may cause considerable shifts in physiology, particularly with respect to thermal tolerance. In this study we compared responses to heat shock at the molecular level in a geographically widespread, surface-dwelling water beetle to a congeneric subterranean species restricted to a single aquifer (Dytiscidae: Hydroporinae). The obligate subterranean beetle Paroster macrosturtensis is known to have a lower thermal tolerance compared to surface lineages (CTmax 38°C cf. 42–46°C), but the genetic basis of this physiological difference has not been characterized. We experimentally manipulated the thermal environment of 24 individuals to demonstrate that both species can mount a heat shock response at high temperatures (35°C), as determined by comparative transcriptomics. However, genes involved in these responses differ between species and a far greater number were differentially expressed in the surface taxon, suggesting it can mount a more robust heat shock response; these data may underpin its higher thermal tolerance compared to subterranean relatives. In contrast, the subterranean species examined not only differentially expressed fewer genes in response to increasing temperatures, but also in the presence of the experimental setup employed here alone. Our results suggest P. macrosturtensis may be comparatively poorly equipped to respond to both thermally induced stress and environmental disturbances more broadly. The molecular findings presented here have conservation implications for P. macrosturtensis and contribute to a growing narrative concerning weakened thermal tolerances in obligate subterranean organisms at the molecular level

Contrasting watershed-scale trends in runoff and sediment yield complicate rangeland water resources planning

Rangelands cover a large portion of the earth's land surface and are undergoing dramatic landscape changes. At the same time, these ecosystems face increasing expectations to meet growing water supply needs. To address major gaps in our understanding of rangeland hydrologic function, we investigated historical watershed-scale runoff and sediment yield in a dynamic landscape in central Texas, USA. We quantified the relationship between precipitation and runoff and analyzed reservoir sediment cores dated using cesium-137 and lead-210 radioisotopes. Local rainfall and streamflow showed no directional trend over a period of 85 years, resulting in a rainfall–runoff ratio that has been resilient to watershed changes. Reservoir sedimentation rates generally were higher before 1963, but have been much lower and very stable since that time. Our findings suggest that (1) rangeland water yields may be stable over long periods despite dramatic landscape changes while (2) these same landscape changes influence sediment yields that impact downstream reservoir storage. Relying on rangelands to meet water needs demands an understanding of how these dynamic landscapes function and a quantification of the physical processes at work