A job response time prediction method for production Grid computing environments

A major obstacle to the widespread adoption of Grid Computing in both the scientific community and industry sector is the difficulty of knowing in advance a job submission running cost that can be used to plan a correct allocation of resources. Traditional distributed computing solutions take advantage of homogeneous and open environments to propose prediction methods that use a detailed analysis of the hardware and software components. However, production Grid computing environments, which are large and use a complex and dynamic set of resources, present a different challenge. In Grid computing the source code of applications, programme libraries, and third-party software are not always available. In addition, Grid security policies may not agree to run hardware or software analysis tools to generate Grid components models. The objective of this research is the prediction of a job response time in production Grid computing environments. The solution is inspired by the concept of predicting future Grid behaviours based on previous experiences learned from heterogeneous Grid workload trace data. The research objective was selected with the aim of improving the Grid resource usability and the administration of Grid environments. The predicted data can be used to allocate resources in advance and inform forecasted finishing time and running costs before submission. The proposed Grid Computing Response Time Prediction (GRTP) method implements several internal stages where the workload traces are mined to produce a response time prediction for a given job. In addition, the GRTP method assesses the predicted result against the actual target job’s response time to inference information that is used to tune the methods setting parameters. The GRTP method was implemented and tested using a cross-validation technique to assess how the proposed solution generalises to independent data sets. The training set was taken from the Grid environment DAS (Distributed ASCI Supercomputer). The two testing sets were taken from AuverGrid and Grid5000 Grid environments Three consecutive tests assuming stable jobs, unstable jobs, and using a job type method to select the most appropriate prediction function were carried out. The tests offered a significant increase in prediction performance for data mining based methods applied in Grid computing environments. For instance, in Grid5000 the GRTP method answered 77 percent of job prediction requests with an error of less than 10 percent. While in the same environment, the most effective and accurate method using workload traces was only able to predict 32 percent of the cases within the same range of error. The GRTP method was able to handle unexpected changes in resources and services which affect the job response time trends and was able to adapt to new scenarios. The tests showed that the proposed GRTP method is capable of predicting job response time requests and it also improves the prediction quality when compared to other current solutions

Quantum mechanics in finite dimensional Hilbert space

The quantum mechanical formalism for position and momentum of a particle in a one dimensional cyclic lattice is constructively developed. Some mathematical features characteristic of the finite dimensional Hilbert space are compared with the infinite dimensional case. The construction of an unbiased basis for state determination is discussed.Comment: 14 pages, no figure

Exogenous estradiol enhances apoptosis in regressing post-partum rat corpora lutea possibly mediated by prolactin

BACKGROUND: In pregnant rats, structural luteal regression takes place after parturition and is associated with cell death by apoptosis. We have recently shown that the hormonal environment is responsible for the fate of the corpora lutea (CL). Changing the levels of circulating hormones in post-partum rats, either by injecting androgen, progesterone, or by allowing dams to suckle, was coupled with a delay in the onset of apoptosis in the CL. The objectives of the present investigation were: i) to examine the effect of exogenous estradiol on apoptosis of the rat CL during post-partum luteal regression; and ii) to evaluate the post-partum luteal expression of the estrogen receptor (ER) genes. METHODS: In a first experiment, rats after parturition were separated from their pups and injected daily with vehicle or estradiol benzoate for 4 days. On day 4 post-partum, animals were sacrificed, blood samples were taken to determine serum concentrations of hormones, and the ovaries were isolated to study apoptosis in situ. In a second experiment, non-lactating rats after parturition received vehicle, estradiol benzoate or estradiol benzoate plus bromoergocryptine for 4 days, and their CL were isolated and used to study apoptosis ex vivo. In a third experiment, we obtained CL from rats on day 15 of pregnancy and from non-lactating rats on day 4 post-partum, and studied the expression of the messenger RNAs (mRNAs) encoding the ERalpha and ERbeta genes. RESULTS: Exogenous administration of estradiol benzoate induced an increase in the number of apoptotic cells within the CL on day 4 post-partum when compared with animals receiving vehicle alone. Animals treated with the estrogen had higher serum prolactin and progesterone concentrations, with no changes in serum androstenedione. Administration of bromoergocryptine blocked the increase in serum prolactin and progesterone concentrations, and DNA fragmentation induced by the estrogen treatment. ERalpha and ERbeta mRNAs were expressed in CL of day 4 post-partum animals at levels similar to those found in CL of day 15 pregnant animals. CONCLUSION: We have established that estradiol accelerates apoptosis in the CL during post-partum luteal regression through a mechanism that possibly involves the secretion of pituitary prolactin. We have also shown that the post-partum rat CL express ERalpha and ERbeta mRNAs suggesting that they can be targeted by estrogen

Ovarian Cancer Research in the Post Genomic Era — Challenges and Opportunities

The field of ovarian cancer research is undergoing major re-examination. Pathologists are defining the disease in new terms, and—having observed discrepancies in its actual cell(s) and tissue(s) of origin—are asking whether or not ovarian cancer truly represents one disease or a complex group of diseases. Further complexity was unveiled after sequencing a large number of high-grade serous ovarian cancer tumor samples (the most frequent ovarian cancer histotype). The experiments uncovered the existence of at least four different molecular subtypes, which standard pathological assessment cannot determine. These discoveries propelled a need for designing novel model systems to study the disease and to develop therapies tailored to the molecular genetics of the tumor. Though there has been no major breakthrough as regards overall patient survival of ovarian cancer in the last 50 years, this chapter summarizes the many challenges and fascinating opportunities scientists face in altering the fatal course of this disease

Fracturas intraoperatorias en las artroplastias totales de rodilla.

Revisamos tipos, mecanismo de producción, tratamiento y resultados de las fracturas intraoperatorias durante la realización de artroplastia total de rodilla. Tuvimos 18 fracturas de 2520 artroplastias, por artrosis en varo en 16 y en valgo en 2. La tibia se fracturó en la parte medial en 8 casos e inmediatemente medial a la tuberosidad tibial anterior en 4. El mecanismo de producción de fractura femoral fue al impactar el componente femoral o reducir los componentes; en la tibia, al realizar el hueco para la quilla o impactar el componente. El tratamiento fue: fijación con cemento solamente, fijación con agujas de Kirschner o tornillos. Se evitó cargar durante las siguientes 6-8 semanas, pero la rehabilitación comenzó inmediatamente. A los dos años o más de seguimiento no había diferencia con las artroplastias sin fractura.The purpose of this study was to review types, pro- duction mechanisms, treatment and results of ours intraope- rative fractures during primary total knee arthroplasty. We had 18 fractures in 2520 primary knee arthroplasties, 16 with varus deformities and valgus in another 2. One patient had corticoids, 15 had overweight and 2 morbid obesity. All implants were posterior stabilised. Type of fracture: 4 were of the medial femoral condyle and 2 lateral; the medial tibial condyle in 8 and on the anterior cortex medial to tibial tubero- sity in 4. Mechanism of injury in the femur was while impac- ting the components or when the trial reduction was perfor- med; in the tibia during the making of the keel house or meanwhile impacting the implants. Treatment: Cement, Kirschner wire or screws. Partial weight bearing was advised for 6-8 weeks. All fractures united. At the last follow-up of two or more years no complaints were found