4,229 research outputs found

    Logistic and Multiple Regression: A Two-Pronged Approach to Accurately Estimate Cost Growth in Major DoD Weapon Systems

    Get PDF
    This research confirms the usefulness of the logistic and multiple regression two-step procedure for assessing cost growth in major DoD weapon systems. We compile programmatic data from the Selected Acquisition Reports (SARs) between 1990 and 2002 for programs covering all defense departments. Our analysis concentrates on cost growth in the procurement appropriations of the Engineering and Manufacturing Development phase of acquisitions. We investigate the use of logistic regression in cost growth analysis to predict whether or not cost growth will occur in a program. If applicable, multiple regression is implemented to predict how much cost growth will occur. Our study focuses on the estimating and support SAR cost variance categories within the procurement appropriations. We study each of these categories individually for significant cost growth characteristics and develop predictive models for each

    Back and forth from cool core to non-cool core: clues from radio-halos

    Full text link
    X-ray astronomers often divide galaxy clusters into two classes: "cool core" (CC) and "non-cool core" (NCC) objects. The origin of this dichotomy has been the subject of debate in recent years, between "evolutionary" models (where clusters can evolve from CC to NCC, mainly through mergers) and "primordial" models (where the state of the cluster is fixed "ab initio" by early mergers or pre-heating). We found that in a well-defined sample (clusters in the GMRT Radio halo survey with available Chandra or XMM-Newton data), none of the objects hosting a giant radio halo can be classified as a cool core. This result suggests that the main mechanisms which can start a large scale synchrotron emission (most likely mergers) are the same that can destroy CC and therefore strongly supports "evolutionary" models of the CC-NCC dichotomy. Moreover combining the number of objects in the CC and NCC state with the number of objects with and without a radio-halo, we estimated that the time scale over which a NCC cluster relaxes to the CC state, should be larger than the typical life-time of radio-halos and likely shorter than about 3 Gyr. This suggests that NCC transform into CC more rapidly than predicted from the cooling time, which is about 10 Gyr in NCC systems, allowing the possibility of a cyclical evolution between the CC and NCC states.Comment: Accepted for publication in A&

    Controversies about a common etiology for eating and mood disorders.

    Get PDF
    Obesity and depression represent a growing health concern worldwide. For many years, basic science and medicine have considered obesity as a metabolic illness, while depression was classified a psychiatric disorder. Despite accumulating evidence suggesting that obesity and depression may share commonalities, the causal link between eating and mood disorders remains to be fully understood. This etiology is highly complex, consisting of multiple environmental and genetic risk factors that interact with each other. In this review, we sought to summarize the preclinical and clinical evidence supporting a common etiology for eating and mood disorders, with a particular emphasis on signaling pathways involved in the maintenance of energy balance and mood stability, among which orexigenic and anorexigenic neuropeptides, metabolic factors, stress responsive hormones, cytokines, and neurotrophic factors

    Second-line status epilepticus treatment: comparison of phenytoin, valproate, and levetiracetam.

    Get PDF
    Phenytoin (PHT), valproic acid (VPA), or levetiracetam (LEV) are commonly used as second-line treatment of status epilepticus (SE), but comparative studies are not available. Among 279 adult SE episodes identified prospectively in our tertiary care hospital over 4 years, we retrospectively identified 187 episodes in which PHT, VPA, or LEV were given after benzodiazepines. Patients with postanoxic SE were not included. Demographics, clinical SE features, failure of second-line treatment to control SE, new handicap, and mortality at hospital discharge were assessed. Uni- and multivariable statistical analyses were applied to compare the three agents. Each compound was used in about one third of SE episodes. VPA failed to control SE in 25.4%, PHT in 41.4%, and LEV in 48.3% of episodes in which these were prescribed. A deadly etiology was more frequent in the VPA group, whereas SE episodes tended to be more severe in the PHT group. After adjustment for these known SE outcome predictors, LEV failed more often than VPA [odds ratio (OR) 2.69; 95% confidence interval (CI) 1.19-6.08]; 16.8% (95% CI: 6.0-31.4%) of second-line treatment failures could be attributed to LEV. PHT was not statistically different from the other two compounds. Second-line treatment did not seem to influence new handicap and mortality, whereas etiology and the SE Severity Score (STESS) were robust independent predictors. Even without significant differences on outcome at discharge, LEV seems less efficient than VPA to control SE after benzodiazepines. A prospective comparative trial is needed to address this potentially concerning finding

    Role of comorbidities in outcome prediction after status epilepticus.

    Get PDF
    Status epilepticus (SE) is associated with significant mortality and morbidity. A reliable prognosis may help better manage medical resources and treatment strategies. We examined the role of preexisting comorbidities on the outcome of patients with SE, an aspect that has received little attention to date. We prospectively studied incident SE episodes in 280 adults occurring over 55 months in our tertiary care hospital, excluding patients with postanoxic encephalopathy. Different models predicting mortality and return to clinical baseline at hospital discharge were compared, which included demographics, SE etiology, a validated clinical Status Epilepticus Severity Score (STESS), and comorbidities (assessed with the Charlson Comorbidity Index) as independent variables. The overall short-term mortality was 14%, and only half of patients returned to their clinical baseline. On bivariate analyses, age, STESS, potentially fatal etiologies, and number of preexisting comorbidities were all significant predictors of both mortality and return to clinical baseline. As compared with the simplest predictive model (including demographics and deadly etiology), adding SE severity and comorbidities resulted in an improved predictive performance (C statistics 0.84 vs. 0.77 for mortality, and 0.86 vs. 0.82. for return to clinical baseline); comorbidities, however, were not independently related to outcome. Considering comorbidities and clinical presentation, in addition to age and etiology, slightly improves the prediction of SE outcome with respect to both survival and functional status. This analysis also emphasizes the robust predictive role of etiology and age

    Feno de cunhã (Clitoria ternatea L.) para acabamento de cordeiros.

    Get PDF
    Resumo: Foram utilizados 32 cordeiros, mestiços, durante setenta dias em estudo na Embrapa Caprinos, em Sobral, CE, para determinar a influência do nível de concentrado em dietas para acabamento de cordeiros em confinamento. Os tratamentos foram as seguintes relaçoes forragem:concentrado: 100%:0% (T1), 85%:15% (T2), 70%:30% (T3) e 55%:45% (T4). A forragem fornecida era feno de cunha e o concentrado era composta de 75% de milho e 25% de farelo de soja. 0 ajuste das proporçoes foi feito diariamente, corn base no consumo de volumoso, servido ad libitum. Corn o aumento do nível de concentrado na dieta dos animais, observou-se incrementos lineares (PO,05) quanto aos tratamentos. Conclui-se que todas as raçoes testadas podem ser utilizadas para terminação de cordeiros em confinamento. Cunhã hay (Clitoria ternatea L.) for finishing of lambs. ABSTRACT - Thirty two crossbred lambs were used in a 70 day study at Embrapa Caprinos, in Sobral, CE, Brazil to evaluate the influence of concentrate levels on finishing diets under confinement. The treatments were the following roughage to concentrate relations: 100% to 0% (T1), 85% to 15% (T2), 70% to 30% (T3) and 55% to 45% (T4). The roughage was cunhã hay (Clitoria ternatea L), and the concentrate was composed of corn (75%) and soybean meal (25%). The adjustments of the proportions were made daily, based on the roughage intake, served ad libitum. It was observed that the total dry matter intake increased, the forage intake decreased, the feed efficiency improved and the daily weight gain increased (P0.05) among treatments. It was concluded that any of the diets studied can be used for finishing lambs
    corecore