Explorer 12 observations of charged particles in the inner radiation zone

Explorer XII satellite observations of charged particles in inner radiation zon

Correlated satellite measurements of low-energy electron precipitation and ground based observations of a visible auroral arc

Comparison of Injun 5 satellite measurements of low energy electron precipitation and ground based observations of visible auroral ar

Electron precipitation in the post midnight sector of the auroral zones

Comprehensive measurements of the angular distributions and energy spectra of electron intensities with electrostatic analyzer arrays on board the low-altitude satellite Injun 5 are reported. These are for the post-midnight sector of the auroral zones during the high-intensity events accompanying magnetic substorms. Precipitation features on closed terrestrial field lines well equatorward of the trapping boundary for energetic electrons with E greater than 45 keV were examined. No evidences of maxima in the differential energy spectra or of strongly field-aligned currents which are indicative of quasi-static electric fields aligned parallel to the geomagnetic field were found. Precipitation of low-energy electron intensities fluctuated on time scales greater than 2 seconds as viewed at the satellite position. This precipitation was characterized by isotropy for all pitch angles outside the atmospheric backscatter cone

Resummation Improved Rapidity Spectrum for Gluon Fusion Higgs Production

Gluon-induced processes such as Higgs production typically exhibit large perturbative corrections. These partially arise from large virtual corrections to the gluon form factor, which at timelike momentum transfer contains Sudakov logarithms evaluated at negative arguments $\ln^2(-1) = -\pi^2$. It has been observed that resumming these terms in the timelike form factor leads to a much improved perturbative convergence for the total cross section. We discuss how to consistently incorporate the resummed form factor into the perturbative predictions for generic cross sections differential in the Born kinematics, including in particular the Higgs rapidity spectrum. We verify that this indeed improves the perturbative convergence, leading to smaller and more reliable perturbative uncertainties, and that this is not affected by cancellations between resummed and unresummed contributions. Combining both fixed-order and resummation uncertainties, the perturbative uncertainty for the total cross section at N$^3$LO$+$N$^3$LL$^\prime_\varphi$ is about a factor of two smaller than at N$^3$LO. The perturbative uncertainty of the rapidity spectrum at NNLO$+$NNLL$^\prime_\varphi$ is similarly reduced compared to NNLO. We also study the analogous resummation for quark-induced processes, namely Higgs production through bottom quark annihilation and the Drell-Yan rapidity spectrum. For the former the resummation leads to a small improvement, while for the latter it confirms the already small uncertainties of the fixed-order predictions.Comment: 30 pages + 17 pages in Appendices, 10 figures; v2: journal version; references added, discussed individual partonic channels for Drell-Ya

New Venture Opportunity Cost of Capital and Financial Contracting

Investments in new ventures involve financial contracts between an entrepreneur and outside investors. Investors, such as venture capital firms, represent well-diversified investors. In contrast, the entrepreneur must commit a substantial fraction of human and financial capital to the venture. Consequently, the entrepreneur's required rate of return depends on total risk, in the context of the entrepreneur’s other assets. In this paper, we use the Capital Asset Pricing Model as an approximation of the asset pricing model used by well-diversified investors. Accordingly, the entrepreneur faces the risk-return tradeoff of the CAPM as the opportunity cost of holding an under-diversified portfolio that includes investment in the venture. We model the required rate of return of the entrepreneur, assuming investment in the venture is one of two assets in the portfolio and that the other is the market portfolio. We explore opportunities for value creation when the parties to a financial contract have different costs of bearing risk. We also present empirical data on factors relevant to new venture cost of capital estimation.

Strategies for sustainable agricultural development in the East African highlands:

Low agricultural productivity, land degradation and poverty are severe interrelated problems in the East African highlands. While the proximate causes of such problems are relatively well known, the underlying causes are many and complex, and depend upon many site-specific factors that vary greatly across the diverse circumstances of the region. In this paper, we argue that the appropriate strategy for sustainable development depends greatly upon the “pathways of development” that are feasible in a given location. We argue that such development pathways will be largely determined by three factors determining comparative advantage: agricultural potential, access to markets, and population density. We conclude the paper with hypotheses about the priorities for policy intervention to achieve sustainable development in the East African highlands. Among these, we suggest that the highest priority for road and irrigation development should be areas close to urban markets with high agricultural potential; that development of input and output markets and credit systems will be most critical in such areas; that increasing food security through increased food crop production or other means is likely to be a key to realizing the potential for more commercial production; that subsidies on the costs of transporting fertilizer to remote, high-potential, food deficit areas should be considered as a lower cost alternative to food aid; and that intensified and more private use of hillsides and grazing areas for sustainable uses such as tree planting may have potential to achieve more rapid and sustainable development of lower potential areas.Land degradation, Sustainable agriculture, Population density,

Trapped radiation experiment

Trapped radiation detector on Mariner IV space probe measurement of outer Van Allen belt - feasibility of detecting trapped radiation at Mar

Measuring non-Gaussian fluctuations through incoherent Cooper pair current

We study a Josephson junction (JJ) in the regime of incoherent Cooper pair tunneling, capacitively coupled to a nonequilibrium noise source. The current-voltage (I-V) characteristics of the JJ are sensitive to the excess voltage fluctuations in the source, and can thus be used for wide-band noise detection. Under weak driving, the odd part of the I-V can be related to the second cumulant of noise, whereas the even part is due to the third cumulant. After calibration, one can measure the Fano factors for the noise source, and get information about the frequency dependence of the noise.Comment: 4 pages, 4 figure

Foray search: An effective systematic dispersal strategy in fragmented landscapes

In the absence of evidence to the contrary, population models generally assume that the dispersal trajectories of animals are random, but systematic dispersal could be more efficient at detecting new habitat and may therefore constitute a more realistic assumption. Here, we investigate, by means of simulations, the properties of a potentially widespread systematic dispersal strategy termed "foray search." Foray search was more efficient in detecting suitable habitat than was random dispersal in most landscapes and was less subject to energetic constraints. However, it also resulted in considerably shorter net dispersed distances and higher mortality per net dispersed distance than did random dispersal, and it would therefore be likely to lead to lower dispersal rates toward the margins of population networks. Consequently, the use of foray search by dispersers could crucially affect the extinction-colonization balance of metapopulations and the evolution of dispersal rates. We conclude that population models need to take the dispersal trajectories of individuals into account in order to make reliable predictions