147 research outputs found

    BIODIESEL AS A SUBSTITUTE FOR PETROLEUM DIESEL IN A STOCHASTIC ENVIRONMENT

    Get PDF
    Policy makers should consider price volatility effects when determining appropriate spending levels for alternative fuel programs.Resource /Energy Economics and Policy,

    BIODIESEL AS A SUBSTITUTE FOR PETROLEUM DIESEL IN A STOCHASTIC ENVIRONMENT

    Get PDF
    The objective of the research presented in this paper is the development of a stochastic adoption threshold. The option pricing approach for modeling investment under uncertainty is extended for the case of comparing two stochastic input prices associated with inputs that are perfect substitutes in a production process. Based on this methodology, a threshold decision rule influenced by the drift and volatility of these two input prices is developed. Theoretical results established an empirical link for measuring the tradeoff of a relatively more expensive input (biodiesel) with lower price drift and volatility compared with a lower but more volatile priced input (petroleum diesel).option pricing, production, renewable fuels, technology adoption under uncertainty, Resource /Energy Economics and Policy,

    Suitability of PSA-detected localised prostate cancers for focal therapy: Experience from the ProtecT study

    Get PDF
    This article is available through a Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License. Copyright @ 2011 Cancer Research UK.Background: Contemporary screening for prostate cancer frequently identifies small volume, low-grade lesions. Some clinicians have advocated focal prostatic ablation as an alternative to more aggressive interventions to manage these lesions. To identify which patients might benefit from focal ablative techniques, we analysed the surgical specimens of a large sample of population-detected men undergoing radical prostatectomy as part of a randomised clinical trial. Methods: Surgical specimens from 525 men who underwent prostatectomy within the ProtecT study were analysed to determine tumour volume, location and grade. These findings were compared with information available in the biopsy specimen to examine whether focal therapy could be provided appropriately. Results: Solitary cancers were found in prostatectomy specimens from 19% (100 out of 525) of men. In addition, 73 out of 425 (17%) men had multiple cancers with a solitary significant tumour focus. Thus, 173 out of 525 (33%) men had tumours potentially suitable for focal therapy. The majority of these were small, well-differentiated lesions that appeared to be pathologically insignificant (38–66%). Criteria used to select patients for focal prostatic ablation underestimated the cancer's significance in 26% (34 out of 130) of men and resulted in overtreatment in more than half. Only 18% (24 out of 130) of men presumed eligible for focal therapy, actually had significant solitary lesions. Conclusion: Focal therapy appears inappropriate for the majority of men presenting with prostate-specific antigen-detected localised prostate cancer. Unifocal prostate cancers suitable for focal ablation are difficult to identify pre-operatively using biopsy alone. Most lesions meeting criteria for focal ablation were either more aggressive than expected or posed little threat of progression.National Institute for Health Researc

    Structural and mechanistic basis of σ-dependent transcriptional pausing

    Get PDF
    In σ-dependent transcriptional pausing, the transcription initiation factor σ, translocating with RNA polymerase (RNAP), makes sequence-specific protein-DNA interactions with a promoter-like sequence element in the transcribed region, inducing pausing. It has been proposed that, in σ-dependent pausing, the RNAP active center can access off-pathway “backtracked” states that are substrates for the transcript-cleavage factors of the Gre family, and on-pathway “scrunched” states that mediate pause escape. Here, using site-specific protein-DNA photocrosslinking to define positions of the RNAP trailing and leading edges and of σ relative to DNA at the λPR’ promoter, we show directly that σ-dependent pausing in the absence of GreB in vitro predominantly involves a state backtracked by 2-4 bp, and that σ-dependent pausing in the presence of GreB in vitro and in vivo predominantly involves a state scrunched by 2-3 bp. Analogous experiments with a library of 47 (∼16,000) transcribed-region sequences show that the state scrunched by 2-3 bp--and only that state--is associated with the consensus sequence, T-3N-2Y-1G+1, (where -1 corresponds to the position of the RNA 3’ end), which is identical to the consensus for pausing in initial transcription, and which is related to the consensus for pausing in transcription elongation. Experiments with heteroduplex templates show that sequence information at position T-3 resides in the DNA nontemplate strand. A cryo-EM structure of a complex engaged in σ-dependent pausing reveals positions of DNA scrunching on the DNA nontemplate and template strands and suggests that position T-3 of the consensus sequence exerts its effects by facilitating scrunching

    Association of various reproductive rights, domestic violence and marital rape with depression among Pakistani women

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Depression among women is common in developing countries. Gender inequality can contribute to women's risk for depression. Lack of reproductive and sexual rights is an important marker of gender inequality and women do not have the freedom to express their reproductive and sexual needs in many parts of the world. Therefore we designed this study to determine the association of depression with lack of various reproductive rights and domestic violence among married women in Karachi, Pakistan.</p> <p>Methods</p> <p>A case-control study with 152 cases and 152 controls, which included women 15-48 years, recruited from two teaching hospitals from 1<sup>st </sup>June 2007 through 31<sup>st </sup>August 2007. The SRQ was administered to all subjects. A cut off score of 8 was used to confirm cases of depression diagnosed by physicians, and to exclude cases of depression from the controls. Self-administered questionnaire was used to assess the risk factors.</p> <p>Results</p> <p>61% of the cases and 43% of the controls were ever abused by spouse and the frequency of marital rape was 33% in cases and 13% in controls. After adjusting for the effects of other variables in the model, less than 18 years of age at marriage (OR 2.00; 95% CI = 1.07, 3.7), decision for marriage by parents (OR 3.51; 95% CI = 1.67, 7.37), abuse by in laws (OR 4.91; 95% CI = 2.66, 9.06), ≤ 3 hours per day spent with husband (OR 2.33; 95% CI = 1.34, 4.08), frequency of intercourse ≤ 2 times per week (OR 1.85; 95% CI = 1.06, 3.22) and marital rape (OR 3.03; 95% CI = 1.50, 6.11) were associated with depression among women.</p> <p>Conclusion</p> <p>In our study depression in married women was associated with younger age at marriage, lack of autonomy in marriage decisions, marital rape and domestic abuse by in-laws. Efforts should be directed towards creating awareness about the reproductive and sexual rights of women in Pakistan. Physicians should be trained to screen and identify women who may be at risk for psychological distress as a result of denial of reproductive rights so that they can support positive mental health outcomes through individual, family or marital counseling.</p

    Seroprevalence and correlates of HIV, syphilis, and hepatitis B and C virus among intrapartum patients in Kabul, Afghanistan

    Get PDF
    BackgroundLittle current information is available for prevalence of vertically-transmitted infections among the Afghan population. The purpose of this study is to determine prevalence and correlates of human immunodeficiency virus (HIV), syphilis, and hepatitis B and C infection among obstetric patients and model hepatitis B vaccination approaches in Kabul, Afghanistan.MethodsThis cross-sectional study was conducted at three government maternity hospitals in Kabul, Afghanistan from June through September, 2006. Consecutively-enrolled participants completed an interviewer-administered survey and whole blood rapid testing with serum confirmation for antibodies to HIV, T. pallidum, and HCV, and HBsAg. Descriptive data and prevalence of infection were calculated, with logistic regression used to identify correlates of HBV infection. Modeling was performed to determine impact of current and birth dose vaccination strategies on HBV morbidity and mortality.ResultsAmong 4452 women, prevalence of HBsAg was 1.53% (95% CI: 1.18 - 1.94) and anti-HCV was 0.31% (95% CI: 0.17 - 0.53). No cases of HIV or syphilis were detected. In univariate analysis, HBsAg was associated with husband's level of education (OR = 1.13, 95% CI: 1.01 - 1.26). Modeling indicated that introduction of birth dose vaccination would not significantly reduce hepatitis-related morbidity or mortality for the measured HBsAg prevalence.ConclusionIntrapartum whole blood rapid testing for HIV, syphilis, HBV, and HCV was acceptable to patients in Afghanistan. Though HBsAg prevalence is relatively low, periodic assessments should be performed to determine birth dose vaccination recommendations for this setting

    Novel Murine Infection Models Provide Deep Insights into the “Ménage à Trois” of Campylobacter jejuni, Microbiota and Host Innate Immunity

    Get PDF
    BACKGROUND: Although Campylobacter jejuni-infections have a high prevalence worldwide and represent a significant socioeconomic burden, it is still not well understood how C. jejuni causes intestinal inflammation. Detailed investigation of C. jejuni-mediated intestinal immunopathology is hampered by the lack of appropriate vertebrate models. In particular, mice display colonization resistance against this pathogen. METHODOLOGY/PRINCIPAL FINDINGS: To overcome these limitations we developed a novel C. jejuni-infection model using gnotobiotic mice in which the intestinal flora was eradicated by antibiotic treatment. These animals could then be permanently associated with a complete human (hfa) or murine (mfa) microbiota. After peroral infection C. jejuni colonized the gastrointestinal tract of gnotobiotic and hfa mice for six weeks, whereas mfa mice cleared the pathogen within two days. Strikingly, stable C. jejuni colonization was accompanied by a pro-inflammatory immune response indicated by increased numbers of T- and B-lymphocytes, regulatory T-cells, neutrophils and apoptotic cells, as well as increased concentrations of TNF-α, IL-6, and MCP-1 in the colon mucosa of hfa mice. Analysis of MyD88(-/-), TRIF(-/-), TLR4(-/-), and TLR9(-/-) mice revealed that TLR4- and TLR9-signaling was essential for immunopathology following C. jejuni-infection. Interestingly, C. jejuni-mutant strains deficient in formic acid metabolism and perception induced less intestinal immunopathology compared to the parental strain infection. In summary, the murine gut flora is essential for colonization resistance against C. jejuni and can be overcome by reconstitution of gnotobiotic mice with human flora. Detection of C. jejuni-LPS and -CpG-DNA by host TLR4 and TLR9, respectively, plays a key role in immunopathology. Finally, the host immune response is tightly coupled to bacterial formic acid metabolism and invasion fitness. CONCLUSION/SIGNIFICANCE: We conclude that gnotobiotic and "humanized" mice represent excellent novel C. jejuni-infection and -inflammation models and provide deep insights into the immunological and molecular interplays between C. jejuni, microbiota and innate immunity in human campylobacteriosis

    A rapid screening tool for psychological distress in children 3--6years old: results of a validation study.

    Get PDF
    International audienceABSTRACT: BACKGROUND: The mental health needs of young children in humanitarian contexts often remain unaddressed. The lack of a validated, rapid and simple tool for screening combined with few mental health professionals able to accurately diagnose and provide appropriate care mean that young children remain without care. Here, we present the results of the principle cross-cultural validation of the "Psychological Screening for Young Children aged 3 to 6" (PSYCAa3-6). The PSYCa 3--6 is a simple scale for children 3 to 6 years old administered by non-specialists, to screen young children in crises and thereby refer them to care if needed. METHODS: This study was conducted in Maradi, Niger. The scale was translated into Hausa, using corroboration of independent translations. A cross-cultural validation was implemented using quantitative and qualitative methods. A random sample of 580 mothers or caregivers of children 3 to 6 years old were included. The tool was psychometrically examined and diagnostic properties were assessed comparing the PSYCa 3--6 against a clinical interview as the gold standard. RESULTS: The PSYCa 3--6 Hausa version demonstrated good concurrent validity, as scores correlated with the gold standard and the Clinical Global Impression Severity Scale (CGI-S) [rho = 0.41, p-value = 0.00]. A reduction procedure was used to reduce the scale from 40 to 22 items. The test-retest reliability of the PSYCa 3--6 was found to be high (ICC 0.81, CI95% [0.68; 0.89]). In our sample, although not the purpose of this study, approximately 54 of 580 children required subsequent follow-up with a psychologist. CONCLUSIONS: To our knowledge, this is the first validation of a screening scale for children 3 to 6 years old with a cross-cultural validation component, for use in humanitarian contexts. The Hausa version of the PSYCa 3--6 is a reliable and a valuable screening tool for psychological distress. Further studies to replicate our findings and additional validations of the PSYCa 3--6 in other populations may help improve the delivery of mental health care to children

    α-Tocopheryl succinate promotes selective cell death induced by vitamin K3 in combination with ascorbate

    Get PDF
    BACKGROUND: A strategy to reduce the secondary effects of anti-cancer agents is to potentiate the therapeutic effect by their combination. A combination of vitamin K3 (VK3) and ascorbic acid (AA) exhibited an anti-cancer synergistic effect, associated with extracellular production of H2O2 that promoted cell death. METHODS: The redox-silent vitamin E analogue a-tocopheryl succinate (a-TOS) was used in combination with VK3 and AA to evaluate their effect on prostate cancer cells. RESULTS: Prostate cancer cells were sensitive to a-TOS and VK3 treatment, but resistant to AA upto 3.2mM. When combined, a synergistic effect was found for VK3\u2013AA, whereas a-TOS\u2013VK3 and a-TOS\u2013AA combination showed an antagonist and additive effect, respectively. However, sub-lethal doses of AA\u2013VK3 combination combined with a sub-toxic dose of a-TOS showed to induce efficient cell death that resembles autoschizis. Associated with this cell demise, lipid peroxidation, DNA damage, cytoskeleton alteration, lysosomal\u2013mitochondrial perturbation, and release of cytochrome c without caspase activation were observed. Inhibition of lysosomal proteases did not attenuate cell death induced by the combined agents. Furthermore, cell deaths by apoptosis and autoschizis were detected. CONCLUSION: These finding support the emerging idea that synergistic combinations of some agents can overcome toxicity and other side-effects associated with high doses of single drugs creating the opportunity for therapeutically relevant selectivity

    The genomic architecture of resistance to Campylobacter jejuni intestinal colonisation in chickens

    Get PDF
    Campylobacter is the leading cause of foodborne diarrhoeal illness in humans and is mostly acquired from consumption or handling of contaminated poultry meat. In the absence of effective licensed vaccines and inhibitors, selection for chickens with increased resistance to Campylobacter could potentially reduce its subsequent entry into the food chain. Campylobacter intestinal colonisation levels are influenced by the host genetics of the chicken. In the present study, two chicken populations were used to investigate the genetic architecture of avian resistance to colonisation: (i) a back-cross of two White Leghorn derived inbred lines [(61 x N) x N] known to differ in resistance to Campylobacter colonisation and (ii) a 9th generation advanced intercross (61 x N) line
    corecore