344 research outputs found
Colorado River Basin Study Comments--Grand Coulee Project Hydroelectric Authority
Comments on the Colorado River Basin Study prepared by the the Western Water Policy Review Advisory Commission
Effect of Range Condition on Steer Gains
Range is a vast resource that makes up about 43% of the world\u27s land surface, about 50% of the adjacent United States and slightly over 51% of South Dakota. This land is generally unsuited for cultivation due to low prercipitation shallow soils, poor drainage or temperature restrictions but is well adapted to grazing
Livestock trade network: potential for disease transmission and implications for risk-based surveillance on the island of Mayotte
The island of Mayotte is a department of France, an outermost region of the European Union located in the Indian Ocean between Madagascar and the coast of Eastern Africa. Due to its close connection to the African mainland and neighbouring islands, the island is under constant threat of introduction of infectious diseases of both human and animal origin. Here, using social network analysis and mathematical modelling, we assessed potential implications of livestock movements between communes in Mayotte for risk-based surveillance. Our analyses showed that communes in the central region of Mayotte acted as a hub in the livestock movement network. The majority of livestock movements occurred between communes in the central region and from communes in the central region to those in the outer region. Also, communes in the central region were more likely to be infected earlier than those in the outer region when the spread of an exotic infectious disease was simulated on the livestock movement network. The findings of this study, therefore, suggest that communes in the central region would play a major role in the spread of infectious diseases via livestock movements, which needs to be considered in the design of risk-based surveillance systems in Mayotte
Computable bounds in fork-join queueing systems
In a Fork-Join (FJ) queueing system an upstream fork station splits incoming jobs into N tasks to be further processed by N parallel servers, each with its own queue; the response time of one job is determined, at a downstream join station, by the maximum of the corresponding tasks' response times. This queueing system is useful to the modelling of multi-service systems subject to synchronization constraints, such as MapReduce clusters or multipath routing. Despite their apparent simplicity, FJ systems are hard to analyze.
This paper provides the first computable stochastic bounds on the waiting and response time distributions in FJ systems. We consider four practical scenarios by combining 1a) renewal and 1b) non-renewal arrivals, and 2a) non-blocking and 2b) blocking servers. In the case of non blocking servers we prove that delays scale as O(logN), a law which is known for first moments under renewal input only. In the case of blocking servers, we prove that the same factor of log N dictates the stability region of the system. Simulation results indicate that our bounds are tight, especially at high utilizations, in all four scenarios. A remarkable insight gained from our results is that, at moderate to high utilizations, multipath routing 'makes sense' from a queueing perspective for two paths only, i.e., response times drop the most when N = 2; the technical explanation is that the resequencing (delay) price starts to quickly dominate the tempting gain due to multipath transmissions
Quantitative Assessment of the Risk of Release of Foot-and-Mouth Disease Virus via Export of Bull Semen from Israel
Various foot-and-mouth disease (FMD) virus strains circulate in the Middle East, causing frequent episodes of FMD outbreaks among Israeli livestock. Since the virus is highly resistant in semen, artificial insemination with contaminated bull semen may lead to the infection of the receiver cow. As a non-FMD-free country with vaccination, Israel is currently engaged in trading bull semen only with countries of the same status. The purpose of this study was to assess the risk of release of FMD virus through export of bull semen in order to estimate the risk for FMD-free countries considering purchasing Israeli bull semen. A stochastic risk assessment model was used to estimate this risk, defined as the annual likelihood of exporting at least one ejaculate of bull semen contaminated with viable FMD virus. A total of 45 scenarios were assessed to account for uncertainty and variability around specific parameter estimates and to evaluate the effect of various mitigation measures, such as performing a preexport test on semen ejaculates. Under the most plausible scenario, the annual likelihood of exporting bull semen contaminated with FMD virus had a median of 1.3 * 10(-7) for an export of 100 ejaculates per year. This corresponds to one infected ejaculate exported every 7 million years. Under the worst-case scenario, the median of the risk rose to 7.9 * 10(-5), which is equivalent to the export of one infected ejaculate every 12,000 years. Sensitivity analysis indicated that the most influential parameter is the probability of viral excretion in infected bulls
A phase II feasibility study of carboplatin followed by sequential weekly paclitaxel and gemcitabine as first-line treatment for ovarian cancer
A total of 53 women with chemotherapy-naĂœÂšve stage Ic-IV ovarian cancer were treated with four cycles of carboplatin area under the curve 7 every 3 weeks, followed by four cycles of paclitaxel 70 mgm 2 (days 1, 8, and 15) and gemcitabine 1000 mgm 2 (days 1 and 8) every 3 weeks. In all, 37 (70%) had stage III/IV disease, with 22 (42%) having tumour 42 cm; 38 patients (72%) completed all planned treatment; 27 of the 32 (84%) patients with radiologically evaluable disease had partial or complete responses; and 30 of the 39 patients (77%) with elevated cancer antigen (CA) 125 had a greater than 75% fall in this value. At a median follow-up of 28 months, 31 patients had relapsed with a median progression-free survival of 19.5 months. In total, 79% of patients were alive at 2 years. Common Toxicity Criteria grade 3/4 haematological toxicity, predominantly neutropenia, was seen in 57% of the patients. A certain degree of pulmonary toxicity was observed; eight patients had symptomatic breathlessness, 7 decreased diffusing capacity of the lung for carbon monoxide, and interstitial chest X-ray changes during the weekly phase. In all cases, this toxicity was reversible. No significant neurotoxicity was seen. This regimen is generally well tolerated with encouraging efficacy. However, the observation of pulmonary toxicity, potentially a feature of the weekly taxaneâgemcitabine regimen, was of some concern. Alternative schedules, including 3-weekly taxanes, are currently being evaluated
Foot and Mouth Disease and Cryptosporidiosis: Possible Interaction between Two Emerging Infectious Diseases
During 2001, a large outbreak of foot and mouth disease occurred in the United Kingdom, during which approximately 2,030 confirmed cases of the disease were reported, >6 million animals were slaughtered, and strict restrictions on access to the countryside were imposed. We report a dramatic decline in the reported incidence of human cryptosporidiosis in northwest England during weeks 13â38 in 2001, compared with the previous 11 years. This decline coincided with the period of foot and mouth restrictions. No similar reduction occurred in the other 26 weeks of the year. We also noted a substantial decline in the proportion of human infections caused by the bovine strain (genotype 2) of Cryptosporidium parvum during weeks 13â38 that year but not during the other weeks
Exploring pig trade patterns to inform the design of risk-based disease surveillance and control strategies
An understanding of the patterns of animal contact networks provides essential information for the design of risk-based animal disease surveillance and control strategies. This study characterises pig movements throughout England and Wales between 2009 and 2013 with a view to characterising spatial and temporal patterns, network topology and trade communities. Data were extracted from the Animal and Plant Health Agency (APHA)âs RADAR (Rapid Analysis and Detection of Animal-related Risks) database, and analysed using descriptive and network approaches. A total of 61,937,855 pigs were moved through 872,493 movements of batches in England and Wales during the 5-year study period. Results show that the network exhibited scale-free and small-world topologies, indicating the potential for diseases to quickly spread within the pig industry. The findings also provide suggestions for how risk-based surveillance strategies could be optimised in the country by taking account of highly connected holdings, geographical regions and time periods with the greatest number of movements and pigs moved, as these are likely to be at higher risk for disease introduction. This study is also the first attempt to identify trade communities in the country, information which could be used to facilitate the pig trade and maintain disease-free status across the country in the event of an outbreak
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