Radiation-induced insulator discharge pulses in the CRRES internal discharge monitor satellite experiment

The Internal Discharge Monitor (IDM) was designed to observe electrical pulses from common electrical insulators in space service. The sixteen insulator samples included twelve planar printed circuit boards and four cables. The samples were fully enclosed, mutually isolated, and space radiation penetrated 0.02 cm of aluminum before striking the samples. Pulsing began on the seventh orbit, the maximum pulse rate occurred on the seventeenth orbit when 13 pulses occurred, and the pulses slowly diminished to about one per 3 orbits six months later. After 8 months, the radiation belts abruptly increased and the pulse rates attained a new high. These pulse rates were in agreement with laboratory experience on shorter time scales. Several of the samples never pulsed. If the pulses were not confined within IDM, the physical processes could spread to become a full spacecraft anomaly. The IDM results indicate the rate at which small insulator pulses occur. Small pulses are the seeds of larger satellite electrical anomalies. The pulse rates are compared with space radiation intensities, L shell location, and spectral distributions from the radiation spectrometers on the Combined Release and Radiation Effects Satellite

Bulletin No. 288 - Draingage and Irrigation, Soil, Economic, and Social Conditions, Delta Area, Utah Division 4: Social Conditions

This study is a part of a more comprehensive one which was organized in 1928 for the purpose of ascertaining what conditions existed in bonded irrigation and drainage districts which were unable to. liquidate obligations incurred. The first such area to be studied was the Delta Area in Millard County. This area was selected for this study because of the pressing need for more detailed and wider information than was available to either the farmers or the bondholders and because available facts based on careful study might aid in achieving fairer settlements. These data might also assist other areas in eliminating wastes which multiply in hastily planned undertakings

Matroid and Knapsack Center Problems

In the classic $k$-center problem, we are given a metric graph, and the objective is to open $k$ nodes as centers such that the maximum distance from any vertex to its closest center is minimized. In this paper, we consider two important generalizations of $k$-center, the matroid center problem and the knapsack center problem. Both problems are motivated by recent content distribution network applications. Our contributions can be summarized as follows: 1. We consider the matroid center problem in which the centers are required to form an independent set of a given matroid. We show this problem is NP-hard even on a line. We present a 3-approximation algorithm for the problem on general metrics. We also consider the outlier version of the problem where a given number of vertices can be excluded as the outliers from the solution. We present a 7-approximation for the outlier version. 2. We consider the (multi-)knapsack center problem in which the centers are required to satisfy one (or more) knapsack constraint(s). It is known that the knapsack center problem with a single knapsack constraint admits a 3-approximation. However, when there are at least two knapsack constraints, we show this problem is not approximable at all. To complement the hardness result, we present a polynomial time algorithm that gives a 3-approximate solution such that one knapsack constraint is satisfied and the others may be violated by at most a factor of $1+\epsilon$. We also obtain a 3-approximation for the outlier version that may violate the knapsack constraint by $1+\epsilon$.Comment: A preliminary version of this paper is accepted to IPCO 201

Promotion and tenure for community-engaged research: An examination of promotion and tenure support for community-engaged research at three universities collaborating through a Clinical and Translational Science Award

This is the pre-peer reviewed version of the following article: Marrero DG, Hardwick EJ, Staten LK, Savaiano DA, Odell JD, Comer KF, Saha C. Promotion and Tenure for Community-Engaged Research: An Examination of Promotion and Tenure Support for Community-Engaged Research at Three Universities Collaborating through a Clinical and Translational Science Award. Clin Transl Sci. 2013 Jun;6(3):204-8, which has been published in final form at http://dx.doi.org/10.1111/cts.12061.Introduction. Community engaged health research, an approach to research which includes the participation of communities, promotes the translation of research to address and improve social determinants of health. As a way to encourage community engaged research, the National Institutes of Health required applicants to the Clinical and Translational Science Award (CTSA) to include a community engagement component. Although grant-funding may support an increase in community engaged research, faculty also respond to the rewards and demands of university promotion and tenure standards. This paper measures faculty perception of how three institutions funded by a CTSA support community engaged research in the promotion and tenure process. Methods: At three institutions funded by a CTSA, tenure track and non-tenure track faculty responded to a survey regarding perceptions of how promotion and tenure committees value community engaged research. Results: Faculty view support for community engaged research with some reserve. Only 36% agree that community engaged research is valued in the promotion and tenure process. Discussion: Encouraging community engaged scholarship requires changing the culture and values behind promotion and tenure decisions. Institutions will increase community engaged research and more faculty will adopt its principles, when it is rewarded by promotion and tenure committees

Secondary conidiation of Sphacelia sorghi on sorghum, a novel factor in the epidemiology of ergot disease

Sphacelia sorghi, the ergot pathogen of sorghum in Zimbabwe, causes copious exudation of honeydew containing macroconidia. Within a few days the exudate develops a white crust consisting of a layer of secondary conidia borne above the honeydew surface on a palisade of sterigma-like projecting hyphae which arise from the macroconidia immediately below the honeydew surface. Secondary conidia are windborne, initiate infection and are recognized for the first time to have an important role in the epidemiology of ergot disease of sorghum in Southern Afric

Windborne spread of ergot disease (Claviceps africana) in sorghum A-lines in Zimbabwe

In field trials in Zimbabwe, C. africana spread rapidly through replicated plots of male-sterile sorghum A-lines, from a group of centrally situated, inoculated plants. Prominent secondary conidiation by the pathogen on the surface of exuded honeydew provided airborne spores which were trapped in a Burkard continuous spore trap and showed diurnal peaks in air close to the primary inoculum source. From the rate and pattern of disease spread it is concluded that the characteristic secondary conidia of C. africana were the principal disease agents within the experimental area, and that ergot spread by windborne secondary conidia has significant epidemiological and economic implications for sorghum hybrid breeding in southern Africa

Assessing direct contributions of morphological awareness and prosodic sensitivity to children’s word reading and reading comprehension

We examined the independent contributions of prosodic sensitivity and morphological awareness to word reading, text reading accuracy, and reading comprehension. We did so in a longitudinal study of English-speaking children (N = 70). At 5 to 7 years of age, children completed the metalinguistic measures along with control measures of phonological awareness and vocabulary. Children completed the reading measures two years later. Morphological awareness, but not prosodic sensitivity made a significant independent contribution to word reading, text reading accuracy and reading comprehension. The effects of morphological awareness on reading comprehension remained after controls for word reading. These results suggest that morphological awareness needs to be considered seriously in models of reading development and that prosodic sensitivity might have primarily indirect relations to reading outcomes. Keywords: Morphological Awareness; Prosody; Word Reading; Reading Comprehension

Claviceps africana sp. nov.; the distinctive ergot pathogen of sorghum in Africa

Stromata arising from ergot sclerotia from sorghum in Zimbabwe were different in colour and texture from those of Claviceps sorghi from sorghum in India, compounding other differences in the dynamics of the early stages of parasitism, the sugar composition of honeydew, the quantitative expression of secondary conidiation and the morphology of sclerotia. The distinctive sexual stage forms the basis of describing the African material as a new Claviceps species which also uniquely elaborates a group of dihydrogenated ergot alkaloids that are biosynthetic intermediates leading to the principal product dihydroergosin