The Computer System: Developing a Plan for the School District

Educators must develop a computer strategy to cover all potential needs of their district

Does nitrate deposition following astrophysical ionizing radiation events pose an additional threat to amphibians?

It is known that amphibians are especially susceptible to the combination of heightened UVB radiation and increased nitrate concentrations. Various astrophysical events have been suggested as sources of ionizing radiation that could pose a threat to life on Earth, through destruction of the ozone layer and subsequent increase in UVB, followed by deposition of nitrate. In this study, we investigate whether the nitrate deposition following an ionizing event is sufficiently large to cause an additional stress beyond that of the heightened UVB previously considered. We have converted predicted nitrate depositions to concentration values, utilizing data from the New York State Department of Environmental Conservation Acid Rain Monitoring Network web site. Our results show that the increase in nitrate concentration in bodies of water following the most intense ionization event likely in the last billion years would not be sufficient to cause a serious additional stress on amphibian populations and may actually provide some benefit by acting as fertilizer.Comment: This version is a longer, more detailed draft of an article submitted to the journal Astrobiolog

Evaluating Delayed Write in a Multilevel Caching File System

Delayed write in a multilevel file system cache hierarchy offers a way to improve performance in diverse client/server scenarios, such as integrating mass store into a distributed file system or providing distributed file system access over low-speed links. Using file system traces and cache simulations, we explore extensions and modifications to the traditional client caching model employed in such file systems as AFS, Sprite, and DFS. High cache hit rates at an intermediate cache server—a machine logically interposed between clients and servers that provides cached file service to the clients—combined with high client cache hit rates lend practicality to an integrated mass storage file system. In such a system, magnetic tape or optical-based mass storage devices may be used as a first-class data repository, fronted by disk and RAM caches to offer acceptable access times to the large, but slow, mass storage system. Similarly, a high cache hit rate is necessary for users accessing file systems via low-speed links, where a delayed write intermediate caching server can mediate traffic to make better use of available bandwidth. In an example taken from mobile computing, an intermediate server might be used as a docking station at a user's home. This arrangement would be convenient for users of mobile computers who upload large amounts of data generated while operating in disconnected mode. Simulations of delayed write caching strategies are applicable to both the mass storage and low-speed link scenarios.http://deepblue.lib.umich.edu/bitstream/2027.42/107940/1/citi-tr-95-9.pd

Access Control in a Workstation-Based Distributed Computing Environment

This paper describes the mechanisms employed to control access to system services on the IFS project. We base our distributed computing environment on systems that we trust, and run those systems in physically secure rooms. From that base, we add services, modifying them to interoperate with existing access control mechanisms. Some weaknesses remain in our environment; we conclude with a description of present vulnerabilities and future plans.http://deepblue.lib.umich.edu/bitstream/2027.42/107869/1/citi-tr-90-2.pd

The Effects of Bedding Pack Clean-out in Hoop Barns for Feedlot Cattle

Bedded hoop barns have become popular for feeding beef cattle. The cattle are kept in the hoop barn, which is bedded to form a manure pack. ISU work has shown that the cattle perform well. However, producers question how to manage the pack and when to clean out. The objective of this study was to compare three clean-out strategies (none, once, and twice) for beef cattle fed in hoop barns

Resource Accessibility, Wealth Neutrality, and Tax Yield in Montana

Until litigation reaches the point where both sides are willing to listen to data, so much so that states actively monitor themselves and that plaintiffs concede when sophisticated data deny genuine differences, plaintiffs and states and children will suffer equally in lengthy and expensive litigation

Effects of Stocking Density on Steer Performance and Carcass Characteristics in Bedded Hoop and Open Front Confinement Facilities: Progress Report

Interest in feeding cattle in bedded confinement facilities has grown in part due to increased regulations regarding open feedlot runoff. Work in Iowa has documented that cattle confined in a bedded hoop barn perform similarly to cattle fed in an open feedlot with shelter. The work was done with a stocking density of 50 sq ft per steer in the bedded hoop barn. A hoop barn is a more expensive facility system compared with open lot configurations. Fixed costs (facilities) are partially determined by stocking density. The objective of this study was to determine the effects of increased stocking density on performance and carcass characteristics of steers fed in bedded hoop and bedded open front facilities. The trials were conducted in 2008 and 2009 at the ISU Armstrong Research Farm, Lewis, IA. The hoop barn was stocked with 40, 45, and 50 head per pen resulting in 50, 45, and 40 sq ft per steer, respectively. In the open front cattle feeding facility, pens were constructed to confine the cattle on concrete with bedding. Again the stocking density was 50, 45, and 40 sq ft per steer. In all trials, there was one stocking density per housing type per trial. The diet fed was 45.0% dry corn, 14.8% ground hay, 36.8% modified distillers grains, and 3.4% supplement on an as fed basis. The total diet was approximately 69% dry matter. Because the project is on going, no statistical analysis was performed. However, the cattle performance and carcass characteristics seemed to be similar across all facilities and stocking densities. There may be a trend for slightly less average daily gain for the highest stocking densities (6% less in the hoop and 3% less in the open front). Bunk space may be a factor in cattle performance as well as density. However, without more replications and statistical analysis, no conclusions can be made at this time

Effects of Dietary Echinacea purpurea on PRRSV-infected Nursery Pigs

The effect of dietary additions of Echinacea purpurea on the rate of rate of growth, viremia, and ontogeny of the humoral antibody response against porcine reproductive and respiratory syndrome virus (PRRSV) infection was evaluated in weaned pigs. In three replicates, weaned pigs (18 ± 1 day of age) from a PRRSV-naïve herd were randomly allotted to one of four pens (diets) in two rooms, each pen containing five pigs. Each pen of pigs (pens) began one of four dietary treatments 1 week before inoculation with PRRSV: 1) basal ration plus carbadox (0.055 g/kg); 2) basal ration plus Echinacea I (2% of the total ration); 3) basal ration plus Echinacea II (4% of the total ration); and 4) basal ration composed of corn, soybean meal, whey, and supplemented essential vitamins and minerals. E. purpurea was purchased in powder form and determined by chemical analysis to contain 1.35% cichoric acid. Seven days after starting the diets (day 7), all pigs in one room were intranasally inoculated with PRRSV isolate ATCC VR-2332 at a concentration of 10 4 TCID50 /ml. To monitor the effects of diet and PRRSV infection, body weight and blood samples were collected from all pigs at 7-day intervals (day 0 to 42). Serum samples were analyzed for the presence of PRRSV and PRRSV-specific antibodies. All inoculated pigs become infected with PRRSV and all uninoculated pigs remained free of infection. PRRSV-infected pigs had a lower percentage increase in body weight between day 7 and 42 compared with uninfected animals (P\u3c0.06). There were no differences in body weight, average daily gain (ADG), average daily feed intake (ADFI), or gain:feed ratio (G:F) in PRRSV-infected compared with uninfected animals. Animals receiving diets supplemented with Echinacea (treatments 2 and 3), no differences were observed in percentage increase in body weight, ADG, ADFI, and G:F ratio in either the PRRSV-infected and the uninfected pigs. Among PRRSV-infected animals, dietary Echinacea did not affect the rate or level of the ELISAdetectable antibody response day 7 to 42 or the level and duration of PRRSV in serum. Under the conditions of this study, dietary Echinacea did not reverse the growthinhibiting effects of PRRSV, did not exhibit antiviral effects and did not show any evidence of immunostimulatory properties

The Rising Incidence of Type 1 Diabetes Is Accounted for by Cases With Lower-Risk Human Leukocyte Antigen Genotypes

OBJECTIVE—The rising incidence of type 1 diabetes has been attributed to environment, implying a lesser role for genetic susceptibility. However, the rise could be accounted for by either more cases with classic high-risk genes or by cases with other risk genes. Separately, for any degree of genetic susceptibility, age at presentation may decrease in a permissive environment. To examine these possibilities, human leukocyte antigen (HLA) class II DRB1 genes known to confer risk for type 1 diabetes were analyzed in relation to year of birth and age at diagnosis over the last five decades