58 research outputs found

    Bacteriophages of Helicobacter pylori

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    The bacterium Helicobacter pylori colonize the stomach in approximately half of the world’s population. Infection with this bacterium is associated with gastritis, peptic ulcer, adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Besides being a pathogen with worldwide prevalence, H. pylori show increasingly high antibiotic resistance rates, making the development of new therapeutic strategies against this bacterium challenging. Furthermore, H. pylori is a genetically diverse bacterium, which may be influenced by the presence of mobile genomic elements, including prophages. In this review, we analyze these issues and summarize various reports and findings related to phages and H. pylori, discussing the relationship between the presence of these elements and the genomic diversity, virulence, and fitness of this bacterium. We also analyze the state of the knowledge on the potential utility of bacteriophages as a therapeutic strategy for H. pylori.This work was supported by the following sources: AM is a recipient of a scholarship from the Centro de Estudios Interdisciplinarios Básicos y Aplicados (CEIBA Foundation), Colombia. AM, JS, and AT are recipients of a project grant (120380763025/2018) from the Departamento Administrativo de Ciencia, Tecnología e Innovación de Colombia (Colciencias) and a project grant (PPTA_7676) from Research Vice-Rectory, Pontificia Universidad Javeriana. FV is the recipient of a project grant (PTDC/BTM-SAL/28978/2017) from the Fundação para a Ciência e a Tecnologia (FCT).info:eu-repo/semantics/publishedVersio

    Draft Genome Sequences of 29 Helicobacter pylori Strains Isolated from Colombia

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    Here, we present the draft genome sequences of 29 Colombian Helicobacter pylori strains. These strains were isolated in Bogotá, Colombia, from patients diagnosed with chronic gastritis. The genomic characterization of these strains will provide more information on the genetic composition of H. pylori strains from Colombia.We thank the entities that financially supported the development of this work. A.B.M. is a recipient of a scholarship from the Centro de Estudios Interdisciplinarios Básicos y Aplicados (CEIBA) Foundation, Colombia; and A.B.M., C.A., J.S., and A.A.T.-R. are recipients of a project grant (120380763025/2018) from MinCiencias, Colombia. The work is partially supported by Research Vice-Rectory, Pontificia Universidad Javeriana (PPTA_7676) and F.P.I.T. BanRepCultural (project 3956). F.F.V. is financed by national funds from the Fundação para a Ciência e a Tecnologia (FCT) through an assistant researcher grant (CEECIND/03023/2017), a project grant (PTDC/BTM-SAL/28978/2017), and projects UIDB/04138/2020 and UIDP/04138/2020; these funds partially supported this work. The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.info:eu-repo/semantics/publishedVersio

    Modelización de la demanda de energía eléctrica: más allá de la normalidad

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    La característica principal que diferencia los mercados de electricidad de otros mercados corresponde con la necesidad de producir la energía en el mismo instante que esta es consumida, a tal punto que en tiempo real los sistemas deben mantener un perfecto balance: en cada momento la demanda de energía eléctrica es igual a la generación. Esta característica impide, por ejemplo, el arbitraje intertemporal por parte de quienes realizan transacciones en este mercado. Al respecto, al modelizar la demanda, es común encontrar análisis econométricos que consideren el supuesto de normalidad; sin embargo, este supuesto puede ignorar, a priori, una eventual presencia de sesgo, curtosis o momentos de orden superior en esta variable. En este trabajo se estudia el enfoque seminoparamétrico (SNP) para describir la demanda de energía eléctrica en Colombia y los residuales de un proceso ARIMA. Se propone la selección de funciones de densidad de probabilidad en términos de una expansión Gram-Charlier finita ajustada por el criterio de máxima verosimilitud. Como caso de estudio se considera la demanda de energía eléctrica en el mercado colombiano. Como resultado se encuentra que la distribución de tipo SNP logra mejor ajuste que la distribución normal para algunas transformaciones de la demanda de energía eléctrica donde se pueden llegar a requerir más de cuatro momentos para representar esta variable.The main characteristic that differentiates electricity markets from other markets corresponds to the need to produce energy at the same time it is consumed, to such an extent that in real time the systems must maintain a perfect balance: at each moment the demand for electrical energy is equal to its generation. This characteristic prevents, for example, intertemporal arbitrage by those who carry out transactions in this market. In this regard, when modelling demand, it is common to find econometric analyzes that consider the assumption of normality; however, this assumption may ignore, a priori, an eventual presence of bias, kurtosis or higher order moments in this variable. In this paper, the Semi-Nonparametric approach (SNP) is studied to describe the demand for electricity in Colombia and the residuals of an ARIMA process. We propose the selection of probability density functions in terms of a finite Gram-Charlier expansion adjusted by the criterion of maximum likelihood. As a case study, the demand for electrical energy in the Colombian market is considered. As a result, it is found that the SNP type distribution achieves better adjustment than the normal distribution for some transformations of the electrical energy demand where it can be required more than four moments to represent this variable

    Modelización de la demanda de energía eléctrica: más allá de la normalidad

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    This work proposes a model of electrical energy demand based on time series methods and semi-nonparametric statistics (SNP). This allows knowing not only the expected value of the demand but also its probability distribution so that, by calculating metrics such as the Quantile Risk Metrics, decisions can be made based on less or more extreme values favorable than the expected value. The results show that in the case of electricity demand in the Colombian market between 2000 and 2018, the probability distribution of the average daily demand is leptokurtic. That is, extreme events occur more frequently than those assumed by a normal distribution. Thus, the Gaussian distribution assumption leads to undervaluation of risk in terms of undervaluation of the frequency of extreme values.Este trabajo propone un modelo de demanda de energía eléctrica basado en métodos de series de tiempo y estadística semi-noparamétrica (SNP). Esto permite conocer no solo el valor esperado de la demanda sino también su distribución de probabilidad de manera que, mediante el cálculo de métricas como la Medida de Riesgo de Cuantil (Quantile Risk Metrics), se puedan tomar decisiones basadas en valores extremos menos o más favorables que el valor esperado. Los resultados muestran que para el caso de la demanda de energía eléctrica del mercado colombiano entre los años 2000 y 2018 la distribución de probabilidad de la demanda diaria promedio es leptocúrtica. Es decir, los eventos extremos ocurren con mayor frecuencia que aquellos que suponen una distribución normal. De modo que, el supuesto de distribución gaussiana conlleva a la subvaloración del riesgo en términos de la subvaloración de la frecuencia de valores extremos

    Enhancing customer-based brand equity through CSR in the hospitality sector

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    Corporate social responsibility is considered an important element in the development of brand equity. Extant research in this context is mainly focused on the relationship between this corporate philosophy and financial performance, overlooking its potential to develop competitive advantages through brand equity dimensions. The aim of this research is to explore the impact of socially responsible aspects on hotel brand equity. To test the proposed model personal surveys of hotel customers were conducted. A structural equation model was developed to test the research hypotheses. The findings show that corporate social responsibility has positive effects on brand image, perceived quality, brand awareness, and brand loyalty

    Clinical Features of Cardio-Renal Syndrome in a Cohort of Consecutive Patients Admitted to an Internal Medicine Ward

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    Introduction: Cardiorenal syndrome (CRS) is a disorder of the heart and kidney whereby interactions between the 2 organs can occur. We recorded the clinical features of CRS in patients consecutively admitted to an Internal Medicine ward. Patients and Methods: We retrospectively analyzed the anthropometric, history, clinical, biochemical and treatment characteristics in 438 out of 2,998 subjects (14.6%) admitted to our unit (from June 2007 to December 2009), diagnosed with CRS, according to Acute Dialysis Quality Initiative (ADQI) recommendations. Estimated glomerular filtration (eGFR) was calculated using several equations: MDRD (Modification of Diet in Renal Disease; 2 variations GFRMDRD186, GFRMDRD175), Mayo, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockroft-Gault. Results: Mean age was 80±8 years, 222 (50.6%) were males, 321 (73.2%) were smokers, 229 (52.2%) were diabetic, 207 (47.2%) had a history of acute myocardial infarction, 167 (38.1%) had angina, 135 (30.8%) were affected by cerebrovascular disease, 339 (77.3%) had peripheral arterial disease. CRS was type 1 in 211 cases (48.2%), type 2 in 96 (21.9%), type 3 in 88 (20.1%), type 4 in 29 (6.6%) and type 5 in 14 (3.2%). eGFR, calculated by different formulae, ranged between 31 and 36 ml/min/1.73 m2. GFR was lower in CRS type 3 than in the other types, and the values ranged between 24 and 27 ml/min/1.73 m2. Mean hospital length-of-stay (LOS) was 9.8±6.3 days. Diuretics were the most prescribed medication (78.7%); only 5 patients underwent haemodialysis. Conclusions: CRS is common, especially in the elderly. CRS Type 1 was the prevalent subset and patients had stage 3-4 renal insufficiency. Results obtained from the GFR equations were similar although the Mayo equation tended to overestimate the eGFR

    Measuring Corporate Social Responsibility in tourism: Development and validation of an efficient measurement scale in the hospitality industry.

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    ABSTRAC: This article aims at developing an efficient measurement scale for corporate social responsibility in the tourism industry, given the contextual character that is recognized in the practice of this construct. Indicators were generated on the basis of a literature review and qualitative research. To assess the reliability and validity, first- and second-order confirmatory factor analysis were carried out. Results show a multidimensional structure of this construct—including economic, social, and environmental issues. This study contributes to the advancement of knowledge in the field of social responsibility through its practical application regarding concepts of sustainable development which have mainly been theoretical

    Effect of SGLT2 inhibitors on stroke and atrial fibrillation in diabetic kidney disease: Results from the CREDENCE trial and meta-analysis

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    BACKGROUND AND PURPOSE: Chronic kidney disease with reduced estimated glomerular filtration rate or elevated albuminuria increases risk for ischemic and hemorrhagic stroke. This study assessed the effects of sodium glucose cotransporter 2 inhibitors (SGLT2i) on stroke and atrial fibrillation/flutter (AF/AFL) from CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation) and a meta-Analysis of large cardiovascular outcome trials (CVOTs) of SGLT2i in type 2 diabetes mellitus. METHODS: CREDENCE randomized 4401 participants with type 2 diabetes mellitus and chronic kidney disease to canagliflozin or placebo. Post hoc, we estimated effects on fatal or nonfatal stroke, stroke subtypes, and intermediate markers of stroke risk including AF/AFL. Stroke and AF/AFL data from 3 other completed large CVOTs and CREDENCE were pooled using random-effects meta-Analysis. RESULTS: In CREDENCE, 142 participants experienced a stroke during follow-up (10.9/1000 patient-years with canagliflozin, 14.2/1000 patient-years with placebo; hazard ratio [HR], 0.77 [95% CI, 0.55-1.08]). Effects by stroke subtypes were: ischemic (HR, 0.88 [95% CI, 0.61-1.28]; n=111), hemorrhagic (HR, 0.50 [95% CI, 0.19-1.32]; n=18), and undetermined (HR, 0.54 [95% CI, 0.20-1.46]; n=17). There was no clear effect on AF/AFL (HR, 0.76 [95% CI, 0.53-1.10]; n=115). The overall effects in the 4 CVOTs combined were: Total stroke (HRpooled, 0.96 [95% CI, 0.82-1.12]), ischemic stroke (HRpooled, 1.01 [95% CI, 0.89-1.14]), hemorrhagic stroke (HRpooled, 0.50 [95% CI, 0.30-0.83]), undetermined stroke (HRpooled, 0.86 [95% CI, 0.49-1.51]), and AF/AFL (HRpooled, 0.81 [95% CI, 0.71-0.93]). There was evidence that SGLT2i effects on total stroke varied by baseline estimated glomerular filtration rate (P=0.01), with protection in the lowest estimated glomerular filtration rate (45 mL/min/1.73 m2]) subgroup (HRpooled, 0.50 [95% CI, 0.31-0.79]). CONCLUSIONS: Although we found no clear effect of SGLT2i on total stroke in CREDENCE or across trials combined, there was some evidence of benefit in preventing hemorrhagic stroke and AF/AFL, as well as total stroke for those with lowest estimated glomerular filtration rate. Future research should focus on confirming these data and exploring potential mechanisms

    Crowdsourcing hypothesis tests: Making transparent how design choices shape research results

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    To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer fiveoriginal research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams renderedstatistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowdsourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.</div
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