Altered Calcium Signaling Following Traumatic Brain Injury

Cell death and dysfunction after traumatic brain injury (TBI) is caused by a primary phase, related to direct mechanical disruption of the brain, and a secondary phase which consists of delayed events initiated at the time of the physical insult. Arguably, the calcium ion contributes greatly to the delayed cell damage and death after TBI. A large, sustained influx of calcium into cells can initiate cell death signaling cascades, through activation of several degradative enzymes, such as proteases and endonucleases. However, a sustained level of intracellular free calcium is not necessarily lethal, but the specific route of calcium entry may couple calcium directly to cell death pathways. Other sources of calcium, such as intracellular calcium stores, can also contribute to cell damage. In addition, calcium-mediated signal transduction pathways in neurons may be perturbed following injury. These latter types of alterations may contribute to abnormal physiology in neurons that do not necessarily die after a traumatic episode. This review provides an overview of experimental evidence that has led to our current understanding of the role of calcium signaling in death and dysfunction following TBI

USAID Contributes to Building National Capacity to Strengthen Food Security: An Example from Mali

Food Security and Poverty, Downloads May 2008-July 2009: 13,

Evaluating the Impact on Market Performance of Investments in Market Information Systems: Methodological Challenges

Evaluating the impact on market performance of investments in agricultural market information systems (MIS) face several methodological challenges. These fall into two broad categories: (a) defining the dimensions of market performance to measure (which is a function of whom the MIS is designed to serve) and identifying reliable indicators of those performance dimensions, and (b) identifying the causal effects of the MIS. The determination of causal effects in turn requires establishing a credible baseline, measuring “treatment effects” (i.e., the effects on economic behavior of receiving improved information from an MIS), dealing with problems of endogenous placement of treatment, and interpreting the validity of stakeholders’ statements and governments’ revealed preferences regarding the utility of MIS. Many of these challenges arise because improved market information can affect the welfare of market actors through improved market polices and increased competition even if those actors do not have direct access to that information. The paper discusses these challenges and identifies approaches that may be useful in developing a “convergence of evidence” concerning whether investment in a given MIS is socially worthwhile.market information services, impact assessment, market transparency, food policies, Agricultural and Food Policy, Food Security and Poverty, International Development, Marketing, Research and Development/Tech Change/Emerging Technologies, Research Methods/ Statistical Methods, C81, D80, H43, N57, 013, Q13,

Assessing the Success of Postfire Reseeding in Semiarid Rangelands Using Terra MODIS

Successful postfire reseeding efforts can aid rangeland ecosystem recovery by rapidly establishing a desired plant community and thereby reducing the likelihood of infestation by invasive plants. Although the success of postfire remediation is critical, few efforts have been made to leverage existing geospatial technologies to develop methodologies to assess reseeding success following a fire. In this study, Terra Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data were used to improve the capacity to assess postfire reseeding rehabilitation efforts, with particular emphasis on the semiarid rangelands of Idaho. Analysis of MODIS data demonstrated a positive effect of reseeding on rangeland ecosystem recovery, as well as differences in vegetation between reseeded areas and burned areas where no reseeding had occurred (P,0.05). We conclude that MODIS provides useful data to assess the success of postfire reseeding

Cryogenic measurements of aerojet GaAs n-JFETs

The spectral noise characteristics of Aerojet gallium arsenide (GaAs) junction field effect transistors (JFET's) have been investigated down to liquid-helium temperatures. Noise characterization was performed with the field effect transistor (FET) in the floating-gate mode, in the grounded-gate mode to determine the lowest noise readings possible, and with an extrinsic silicon photodetector at various detector bias voltages to determine optimum operating conditions. The measurements indicate that the Aerojet GaAs JFET is a quiet and stable device at liquid helium temperatures. Hence, it can be considered a readout line driver or infrared detector preamplifier as well as a host of other cryogenic applications. Its noise performance is superior to silicon (Si) metal oxide semiconductor field effect transistor (MOSFET's) operating at liquid helium temperatures, and is equal to the best Si n channel junction field effect transistor (n-JFET's) operating at 300 K

Dar\u27s Somethin\u27 About Yer I Like / music by John T. Kelly; words by John T. Kelly

Cover: drawing of an African American male talking to an African American female; description reads An Ethiopian Character Creation; Publisher: Weber Fields and Stromberg (New York)https://egrove.olemiss.edu/sharris_a/1036/thumbnail.jp