491 research outputs found

    An Optimal Rule for Switching over to Renewable fuels with Lower Price Volatility: A Case of Jump Diffusion Process

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    This study investigates the optimal switching boundary to a renewable fuel when oil prices exhibit continuous random fluctuations along with occasional discontinuous jumps. In this paper, oil prices are modeled to follow jump diffusion processes. A completeness result is derived. Given that the market is complete the value of a contingent claim is risk neutral expectation of the discounted pay off process. Using the contingent claim analysis of investment under uncertainty, the Hamilton-Jacobi-Bellman (HJB) equation is derived for finding value function and optimal switching boundary. We get a mixed differential-difference equation which would be solved using numerical methods.Demand and Price Analysis, Resource /Energy Economics and Policy,

    Role of male behavior in cervical carcinogenesis among women with one lifetime sexual partner

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    Background: The role of male behavior in the genesis of cervical cancer was examined. In India, where the incidence of cervical cancer is among the highest in the world, promiscuity among women is virtually unknown. In this study, the authors investigated the role of male behavior in cervical carcinogenesis among Indian women who had one lifetime sexual partner. Methods: A case-control study was used. Results. Premarital sexual relationships (relative risk [RR], 1.9; confidence interval, 1.2-3.2) and extramarital sexual relationships (RR, 2.7; confidence interval, 1.5-4.9) of husbands were risk factors. When husbands had sexual relationships both before and during the marriage, their wives' risk of getting cervical cancer increased by 6.9 (CI, 2.3-20.7). Risk also increased with husbands having three or more extramarital sexual partners (RR, 3.05; CI, 1.25-12.6). Sexual contact with prostitutes before or after marriage, however, did not increase the risk. History of sexually transmitted disease before marriage (RR, 2.9) or after marriage (RR, 5.9) was an important risk factor, which persisted after controlling for other factors. Sexual abstinence for 40 or more days after a wife's giving birth or having an abortion provided protection. Sex with uncircumcised men or men circumcised after age 1 year increased the risk of cervical cancer (RR, 4.1). Bidi smoking (bidi is a cheap smoking stick of 4-8 cm, consisting of a rolled piece of dried temburni leaf [Diospyres melanoxylon] containing 0.15-0.25 g of coarsely ground tobacco) for more than 20 years was a significant risk factor (RR = 2.4), whereas cigarette smoking was not a risk factor. Conclusions: Male sexual partners play a role in cervical carcinogenesis

    Analysis of waiting time for elective surgical procedures in neurosurgery department at a tertiary care teaching hospital in NCT, India

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    Background: Reported increases in waiting times for publicly-funded elective surgeries have intensified the need to decrease wait by healthcare providers and hence the study.Methods: Descriptive study done in neurosurgery department, to ascertain waiting times for its elective surgeries, included a retrospective analysis of admitted post-surgical patients and a prospective study using interviews with relevant stakeholders to do a process mapping.Results: Median time from decision of surgery to actual date of surgery was found to be 110.5 days. It was calculated that for optimum utilization of present available OTs, 19 extra beds are required and to address the existing load of patients waiting for their respective surgeries there is a need of 63 additional beds with 2 additional OTs functioning per day.Conclusions: The most common cause of waiting time was unavailability of vacant beds due to mismatch in demand-supply. The reason for postponement of surgery after admission was found to be lack of availability of theatre time followed by patient not being fit for surgery. Shortage of operating time was due to delayed start of operation theatre time. The study recommends improving admission process, restricting OPD time, standardized patient prioritization depending on relevant clinical criteria

    Long-term thermokarst lake development and internal ecological feedbacks: A new reconstruction from Lake Satagay (Yakutia, Siberia)

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    The permafrost-shaped landscape of Central Yakutia is particularly rich in thermokarst lakes, which provide important cultural and ecosystem services to the local population. Climate warming and an intensification of agriculture in alaas systems (i.e. mostly drained basins of large thaw lakes formed during the early Holocene under warm climatic conditions) in the Central Yakutian Lowlands may lead to pronounced changes in water resources, water quality, nutrient loading and biodiversity. This could in turn threaten the livelihoods of affected communities, who depend on functional alaas ecosystems. To better foresee potential future impacts of environmental changes on internal lake ecological processes, it is important to gain a better understanding of how thermokarst lakes reacted to such changes in the past. Here, we present a new paleoenvironmental reconstruction of ecological changes within Lake Satagay (N 63.078, E 117.998, Nyurbinsky District), covering the last ca. 10,800 years. We use sedimentological and XRF-derived geochemical parameters, in addition to the metabarcoding of sedimentary ancient DNA (sedDNA) for diatoms and aquatic plants, and microscopic diatom analyses, to evaluate sedimentological and biodiversity shifts throughout the Holocene. Our study revealed 53 diatom DNA sequence types and 53 species morphologically. High distributions of Stephanodiscus and Fragilaria, among multiple other diatom genera in the early Holocene, indicate that initial formation of this typical alaas lake occurred earlier than expected (i.e. before 10,800 BP). In recent millennia diatom abundance decreased and their community is almost exclusively composed of Pseudostaurosira and Fragilaria. Composition of aquatic plants show an overall dominance of Ceratophyllaceae and strong fluctuations in Potamogetonaceae likely related to lake level and water chemical changes. All proxies investigated support that lake conditions and biotic composition has been resilient since 4,000 BP, but youngest samples since 47 BP indicate that land use influence has been crucial for the lake quality. This study represents a step towards a better understanding of climate and human-impacted alaas lake development and its consequences for their ecosystem services in eastern Siberia in the near future

    Elevated levels of Dickkopf-related protein 3 in seminal plasma of prostate cancer patients

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    <p>Abstract</p> <p>Background</p> <p>Expression of Dkk-3, a secreted putative tumor suppressor, is altered in age-related proliferative disorders of the human prostate. We now investigated the suitability of Dkk-3 as a diagnostic biomarker for prostate cancer (PCa) in seminal plasma (SP).</p> <p>Methods</p> <p>SP samples were obtained from 81 patients prior to TRUS-guided prostate biopsies on the basis of elevated serum prostate-specific antigen (PSA; > 4 ng/mL) levels and/or abnormal digital rectal examination. A sensitive indirect immunoenzymometric assay for Dkk-3 was developed and characterized in detail. SP Dkk-3 and PSA levels were determined and normalized to total SP protein. The diagnostic accuracies of single markers including serum PSA and multivariate models to discriminate patients with positive (N = 40) and negative (N = 41) biopsy findings were investigated.</p> <p>Results</p> <p>Biopsy-confirmed PCa showed significantly higher SP Dkk-3 levels (100.9 ± 12.3 vs. 69.2 ± 9.4 fmol/mg; <it>p </it>= 0.026). Diagnostic accuracy (AUC) of SP Dkk-3 levels (0.633) was enhanced in multivariate models by including serum PSA (model A; AUC 0.658) or both, serum and SP PSA levels (model B; AUC 0.710). In a subpopulation with clinical follow-up > 3 years post-biopsy to ensure veracity of negative biopsy status (positive biopsy N = 21; negative biopsy N = 25) AUCs for SP Dkk-3, model A and B increased to 0.667, 0.724 and 0.777, respectively.</p> <p>Conclusions</p> <p>In multivariate models to detect PCa, inclusion of SP Dkk-3 levels, which were significantly elevated in biopsy-confirmed PCa patients, improved the diagnostic performance compared with serum PSA only.</p

    The Discovery of Putative Urine Markers for the Specific Detection of Prostate Tumor by Integrative Mining of Public Genomic Profiles

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    Urine has emerged as an attractive biofluid for the noninvasive detection of prostate cancer (PCa). There is a strong imperative to discover candidate urinary markers for the clinical diagnosis and prognosis of PCa. The rising flood of various omics profiles presents immense opportunities for the identification of prospective biomarkers. Here we present a simple and efficient strategy to derive candidate urine markers for prostate tumor by mining cancer genomic profiles from public databases. Prostate, bladder and kidney are three major tissues from which cellular matters could be released into urine. To identify urinary markers specific for PCa, upregulated entities that might be shed in exosomes of bladder cancer and kidney cancer are first excluded. Through the ontology-based filtering and further assessment, a reduced list of 19 entities encoding urinary proteins was derived as putative PCa markers. Among them, we have found 10 entities closely associated with the process of tumor cell growth and development by pathway enrichment analysis. Further, using the 10 entities as seeds, we have constructed a protein-protein interaction (PPI) subnetwork and suggested a few urine markers as preferred prognostic markers to monitor the invasion and progression of PCa. Our approach is amenable to discover and prioritize potential markers present in a variety of body fluids for a spectrum of human diseases
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