80 research outputs found

    The valuation of clean spread options: linking electricity, emissions and fuels

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    The purpose of the paper is to present a new pricing method for clean spread options, and to illustrate its main features on a set of numerical examples produced by a dedicated computer code. The novelty of the approach is embedded in the use of a structural model as opposed to reduced-form models which fail to capture properly the fundamental dependencies between the economic factors entering the production process

    Digital inclusion of mature students: Analysis of their attitudes and ICT competences

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    Esta investigación se propone identificar las actitudes y competencias de los estudiantes adultos en relación con el uso de las TIC, con especial atención al uso de plataformas digitales de aprendizaje y redes sociales (Web 2.0). Asimismo, evalúa la incidencia de algunas variables sociodemográficas (género y edad) en el uso estas herramientas y en la autopercepción de los estudiantes sobre sus competencias digitales. Se ha realizado un estudio tipo encuesta con una muestra de 382 estudiantes que acceden a la Universidad de Sevilla a través de las vías establecidas para mayores de 25, de 40 y 45 años. Los resultados ponen de manifiesto una actitud generalmente positiva ante las TIC que puede calificarse como de pragmática, ya que estas herramientas se valoran positivamente en función de sus potenciales beneficios en los procesos de aprendizaje. Se constata a la vez que no han recibido formación específica en el uso de las TIC. El nivel de competencia que este alumnado percibe tener en el uso de estos recursos es medio-bajo. Además, el grupo de estudiantes mayores de 45 años se considera menos competente que los mayores de 25 y de 40 años. En consecuencia, se realizan algunas propuestas para mejorar la participación de los estudiantes maduros en la enseñanza universitaria.This research aims to identify the attitudes and competences of mature students regarding information and communication technologies (ICT), with special focus on digital learning platforms and social networks (Web 2.0). In addition, the study tries to assess the influence of several socio-demographic variables (gender and age) in the use of these tools and in the students’ self-perception of their digital competency. The research uses the survey method and a questionnaire has been applied to a sample of 382 students entering the University of Seville via the special routes for older than 25, than 40 and 45 years. Results showed a general positive attitude towards the ICT, which could also be qualified as pragmatic, since the tools are positively valued based on their potential benefits in the learning processes. Results also point to the fact that students have not been specifically trained in the use of ITC. The level of competency that they claim to possess regarding the use of these resources is medium-low. Furthermore, the over 45 year group declare themselves less competent than the over 25 and 40. Finally, some suggestions are given in order to improve the participation of mature students in Higher Education

    Preservation of York Minster historic limestone by hydrophobic surface coatings

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    Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO 2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from 'breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO/H O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation

    Efficacy of extended infusion of beta-lactam antibiotics for the treatment of febrile neutropenia in haematologic patients: protocol for a randomised, multicentre, open-label, superiority clinical trial (BEATLE)

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    Background: Febrile neutropaenia (FN) is a very common complication in patients with haematological malignancies and is associated with considerable morbidity and mortality. Broad-spectrum antipseudomonal beta-lactam antibiotics (BLA) are routinely used for the treatment of cancer patients with FN. However, the clinical efficacy of BLA may be diminished in these patients because they present with pathophysiological variations that compromise the pharmacokinetic (PK) parameters of these antibiotics. Optimised administration of BLA in prolonged infusions has demonstrated better clinical outcomes in critically ill patients. However, there is a paucity of data on the usefulness of this strategy in patients with FN. The aim of this study is to test the hypothesis that the administration of BLA would be clinically more effective by extended infusion (EI) than by intermittent infusion (II) in haematological patients with FN. Methods: A randomised, multicentre, open-label, superiority clinical trial will be performed. Patients with haematological malignancies undergoing chemotherapy or haematopoietic stem-cell transplant and who have FN and receive empirical antibiotic therapy with cefepime, piperacillin-tazobactam or meropenem will be randomised (1:1) to receive the antibiotic by EI (during half the time of the dosing interval) in the study group, or by II (30 min) in the control group. The primary endpoint will be clinical efficacy, defined as defervescence without modifying the antibiotic treatment administered within the first 5 days of therapy. The primary endpoint will be analysed in the intention-to-treat population. The secondary endpoints will be pharmacokinetic/pharmacodynamic (PK/PD) target achievement, bacteraemia clearance, decrease in C-reactive protein, overall (30-day) case-fatality rate, adverse events and development of a population PK model of the BLA studied. Discussion: Data on the usefulness of BLA administration in patients with FN are scant. Only three clinical studies addressing this issue have been published thus far, with contradictory results. Moreover, these studies had some methodological flaws that limit the interpretation of their findings. If this randomised, multicentre, phase IV, open-label, superiority clinical trial validates the hypothesis that the administration of BLA is clinically more effective by EI than by II in haematological patients with FN, then the daily routine management of these high-risk patients could be changed to improve their outcomes

    Background Light in Potential Sites for the ANTARES Undersea Neutrino Telescope

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    The ANTARES collaboration has performed a series of {\em in situ} measurements to study the background light for a planned undersea neutrino telescope. Such background can be caused by 40^{40}K decays or by biological activity. We report on measurements at two sites in the Mediterranean Sea at depths of 2400~m and 2700~m, respectively. Three photomultiplier tubes were used to measure single counting rates and coincidence rates for pairs of tubes at various distances. The background rate is seen to consist of three components: a constant rate due to 40^{40}K decays, a continuum rate that varies on a time scale of several hours simultaneously over distances up to at least 40~m, and random bursts a few seconds long that are only correlated in time over distances of the order of a meter. A trigger requiring coincidences between nearby photomultiplier tubes should reduce the trigger rate for a neutrino telescope to a manageable level with only a small loss in efficiency.Comment: 18 pages, 8 figures, accepted for publication in Astroparticle Physic

    A Large Multicenter Prospective Study of Community-Onset Healthcare Associated Bacteremic Urinary Tract Infections in the Era of Multidrug Resistance: Even Worse than Hospital Acquired Infections?

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    Introduction: Healthcare-associated (HCA) infections represent a growing public health problem. The aim of this study was to compare community-onset healthcare associated (CO-HCA) bacteremic urinary tract infections (BUTI) and hospital-acquired (HA)-BUTI with special focus on multidrug resistances (MDR) and outcomes. Methods: ITUBRAS-project is a prospective multicenter cohort study of patients with HCA-BUTI. All consecutive hospitalized adult patients with CO-HCA-BUTI or HA-BUTI episode were included in the study. Exclusion criteria were: patients < 18 years old, non-hospitalized patients, bacteremia from another source or primary bacteremia, non-healthcare-related infections and infections caused by unusual pathogens of the urinary tract. The main outcome variable was 30-day all-cause mortality with day 1 as the first day of positive blood culture. Logistic regression was used to analyze factors associated with clinical cure at hospital discharge and with receiving inappropriate initial antibiotic treatment. Cox regression was used to evaluate 30-day all-cause mortality. Results: Four hundred forty-three episodes were included, 223 CO-HCA-BUTI. Patients with CO-HCA-BUTI were older (p < 0.001) and had more underlying diseases (p = 0.029) than those with HA-BUTI. The severity of the acute illness (Pitt score) was also higher in CO-HCA-BUTI (p = 0.026). Overall, a very high rate of MDR profiles (271/443, 61.2%) was observed, with no statistical differences between groups. In multivariable analysis, inadequate empirical treatment was associated with MDR profile (aOR 3.35; 95% CI 1.77–6.35), Pseudomonas aeruginosa (aOR 2.86; 95% CI 1.27–6.44) and Charlson index (aOR 1.11; 95% CI 1.01–1.23). Mortality was not associated with the site of acquisition of the infection or the presence of MDR profile. However, in the logistic regression analyses patients with CO-HCA-BUTI (aOR 0.61; 95% CI 0.40–0.93) were less likely to present clinical cure. Conclusion: The rate of MDR infections was worryingly high in our study. No differences in MDR rates were found between CO-HCA-BUTI and HA-BUTI, in the probability of receiving inappropriate empirical treatment or in 30-day mortality. However, CO-HCA-BUTIs were associated with worse clinical cure. © 2021, The Author(s)

    Susceptibility of HIV-1 Subtypes B′, CRF07_BC and CRF01_AE that Are Predominantly Circulating in China to HIV-1 Entry Inhibitors

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    The B', CRF07_BC and CRF01_AE are the predominant HIV-1 subtypes in China. It is essential to determine their baseline susceptibility to HIV entry inhibitors before these drugs are used in China.The baseline susceptibility of 14 representative HIV-1 isolates (5 CRF07_BC, 4 CRF01_AE, and 5 B'), most of which were R5 viruses, obtained from drug-naïve patients to HIV entry inhibitors, including two fusion inhibitors (enfuvirtide and C34), two CCR5 antagonists (maraviroc and TAK779) and one CXCR4 antagonist (AMD3100), were determined by virus inhibition assay. The sequences of their env genes were amplified and analyzed. These isolates possessed similar susceptibility to C34, but they exhibited different sensitivity to enfuvirtide, maraviroc or TAK779. CRF07_BC isolates, which carried polymorphisms of A578T and V583I in the N-terminal heptad repeat and E630Q, E662A, K665S, A667K and S668N in the C-terminal heptad repeat of gp41, were about 5-fold less sensitive than B' and CRF01_AE isolates to enfuvirtide. Subtype B' isolates with a unique polymorphism site of F317W in V3 loop, were about 4- to 5-fold more sensitive than CRF07_BC and CRF01_AE isolates to maraviroc and TAK779. AMD3100 at the concentration as high as 5 µM exhibited no significant inhibitory activity against any of the isolates tested.Our results suggest that there are significant differences in baseline susceptibility to HIV entry inhibitors among the predominant HIV-1 subtypes in China and the differences may partly result from the naturally occurring polymorphisms in these subtypes. This study provides useful information for rational design of optimal therapeutic regimens for HIV-1-infected patients in China

    The effect of nutritional supplementation on the multifocal electroretinogram in healthy eyes

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    BACKGROUND: Previous studies have demonstrated an increase in macular pigment optical density (MPOD) with lutein (L)-based supplementation in healthy eyes. However, not all studies have assessed whether this increase in MPOD is associated with changes to other measures of retinal function such as the multifocal ERG (mfERG). Some studies also fail to report dietary levels of L and zeaxanthin (Z). Because of the associations between increased levels of L and Z, and reduced risk of AMD, this study was designed to assess the effects of L-based supplementation on mfERG amplitudes and latencies in healthy eyes. METHODS: Multifocal ERG amplitudes, visual acuity, contrast sensitivity, MPOD and dietary levels of L and Z were assessed in this longitudinal, randomized clinical trial. Fifty-two healthy eyes from 52 participants were randomly allocated to receive a L-based supplement (treated group), or no supplement (non-treated group). RESULTS: There were 25 subjects aged 18-77 (mean age ± SD; 48 ± 17) in the treated group and 27 subjects aged 21-69 (mean age ± SD; 43 ± 16) in the non-treated group. All participants attended for three visits: visit one at baseline, visit two at 20 weeks and visit three at 40 weeks. A statistically significant increase in MPOD (F = 17.0, p ≤ 0.001) and shortening of mfERG ring 2 P1 latency (F = 3.69, p = 0.04) was seen in the treated group. CONCLUSIONS: Although the results were not clinically significant, the reported trend for improvement in MPOD and mfERG outcomes warrants further investigation

    Inborn and acquired metabolic defects in cancer

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    The observation that altered metabolism is the fundamental cause of cancer was made by Otto Warburg nearly a century ago. However, the subsequent identification of oncogenes and tumor suppressor genes has displaced Warburg's theory pointing towards genetic aberrations as the underlining cause of cancer. Nevertheless, in the last decade, cancer-associated mutations have been identified in genes coding for tricarboxylic acid cycle (TCA cycle, also known as Krebs cycle) and closely related enzymes that have essential roles in cellular metabolism. These observations have revived interest in Warburg's hypothesis and prompted a flurry of functional studies in the hope of gaining mechanistic insight into the links between mitochondrial dysfunction, metabolic alterations, and cancer. In this review, we discuss the potential pro-oncogenic signaling role of some TCA cycle metabolites and their derivatives (oncometabolites). In particular, we focus on their effects on dioxygenases, a family of oxygen and α-ketoglutarate-dependent enzymes that control, among other things, the levels and activity of the hypoxia-inducible transcription factors and the activity of DNA and histone demethylases

    How safe are the biologicals in treating asthma and rhinitis?

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    A number of biological agents are available or being investigated for the treatment of asthma and rhinitis. The safety profiles of these biologic agents, which may modify allergic and immunological diseases, are still being elucidated. Subcutaneous allergen immunotherapy, the oldest biologic agent in current use, has the highest of frequency of the most serious and life-threatening reaction, anaphylaxis. It is also one of the only disease modifying interventions for allergic rhinitis and asthma. Efforts to seek safer and more effective allergen immunotherapy treatment have led to investigations of alternate routes of delivery and modified immunotherapy formulations. Sublingual immunotherapy appears to be associated with a lower, but not zero, risk of anaphylaxis. No fatalities have been reported to date with sublingual immunotherapy. Immunotherapy with modified formulations containing Th1 adjuvants, DNA sequences containing a CpG motif (CpG) and 3-deacylated monophospholipid A, appears to provide the benefits of subcutaneous immunotherapy with a single course of 4 to 6 preseasonal injections. There were no serious treatment-related adverse events or anaphylaxis in the clinical trials of these two immunotherapy adjuvants. Omalizumab, a monoclonal antibody against IgE, has been associated with a small risk of anaphylaxis, affecting 0.09% to 0.2% of patients. It may also be associated with a higher risk of geohelminth infection in patients at high risk for parasitic infections but it does not appear to affect the response to treatment or severity of the infection
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