1,542 research outputs found

    What is the role of context in fair group recommendations?

    Get PDF
    We investigate the role played by the context, i.e. the situation the group is currently experiencing, in the design of a system that recommends sequences of activities as a multi-objective optimization problem, where the satisfaction of the group and the available time interval are two of the functions to be optimized. In particular, we highlight that the dynamic evolution of the group can be the key contextual feature that has to be considered to produce fair suggestions

    A context-based approach for partitioning big data

    Get PDF
    In recent years, the amount of available data keeps growing at fast rate, and it is therefore crucial to be able to process them in an efficient way. The level of parallelism in tools such as Hadoop or Spark is determined, among other things, by the partitioning applied to the dataset. A common method is to split the data into chunks considering the number of bytes. While this approach may work well for text-based batch processing, there are a number of cases where the dataset contains structured information, such as the time or the spatial coordinates, and one may be interested in exploiting such a structure to improve the partitioning. This could have an impact on the processing time and increase the overall resource usage efficiency. This paper explores an approach based on the notion of context, such as temporal or spatial information, for partitioning the data. We design a context-based multi-dimensional partitioning technique that divides an n 12dimensional space into splits by considering the distribution of the each contextual dimension in the dataset. We tested our approach on a dataset from a touristic scenario, and our experiments show that we are able to improve the efficiency of the resource usage

    Transporte electrogénico en el colon de ratas privadas de sodio : bloqueo de canales epiteliales versus inhibición de la NA, K-ATPASA

    Get PDF
    La privación dietaria de sodio estimula la secreción de aldosterona. En el colon de rata, la aldosterona elevada aumenta la absorción de Na+, pero además torna electrogénico el mecanismo de absorción (normalmente electroneutro). Dicho transporte electrogénico puede suprimirse mediante el bloqueo de los canales epiteliales de Na+ en la membrana apical o la inhibición de la Na, KATPasa de la membrana basolateral. La absorción electrogénica de sodio está estrechamente acoplada al metabolismo aerobio, pero se desconoce si el bloqueo de los canales de Na+ reduce el consumo de oxígeno en igual medida que la inhibición de la Na, K-ATPasa. Se obtuvieron preparados de mucosa aislada del colon distal de ratas alimentadas con una dieta hiposódica por 10 días. Se determinó simultáneamente la corriente de cortocircuito y el consumo de oxígeno en condición basal y luego del bloqueo de canales de Na+ con amilorida (n=12) o de la Na, K-ATPasa con uabaína (n=12). Ambos tratamientos redujeron la corriente de cortocircuito en igual medida (>80%), pero la reducción en el consumo de oxígeno fue mayor con uabaína que con amilorida (p<0.03). Esto se debe probablemente a que la Na, KATPasa cumple otras funciones, además del transporte transepitelial de Na+, que son suprimidas por la uabaína pero no por la amilorida.Dietary sodium deprivation stimulates aldosterone secretion. In the rat colon, high aldosterone levels increases Na+ absorption but also switches the mechanism of Na+ absorption from electroneutral to electrogenic. Such electrogenic transport may be suppressed by either epithelial Na+ channel blockade at the apical membrane or Na, K-ATPase inhibition at the basolateral membrane. Electrogenic Na+ absorption is tightly coupled to aerobic metabolism, but it is not known whether epithelial Na+ channel blockade and Na, KATPase inhibition cause the same degree of reduction in epithelial oxygen consumption. Distal colon isolated mucosa preparations were obtained from rats fed with a low sodium diet for 10 days. Short-circuit current and oxygen consumption were simultaneously measured in baseline condition and after either blocking epithelial Na+ channels with amiloride (n=12) or the Na, KATPase with ouabain (n=12). Both treatments reduced short-circuit current to the same degree, but the reduction in oxygen consumption was larger with ouabain (p<0.03). The difference may be due to the fact that Na, K-ATPase has other functions besides transepithelial Na+ transport, which are suppressed by ouabain but not by amiloride.Fil: Carra, Graciela E.. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: Galella, Flavia. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: Widenberg, Johan. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: Ibáñez, Jorge E.. Universidad Nacional de Cuyo. Facultad de Ciencias MédicasFil: Saraví, Fernando D.. Universidad Nacional de Cuyo. Facultad de Ciencias Médica

    Learning curve for laparoscopic cholecystectomy has not been defined: A systematic review

    Get PDF
    Background: Laparoscopic cholecystectomy is one of the most performed surgeries worldwide but its learning curve is still unclear. Methods: A systematic review was conducted according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Two independent reviewers searched the literature in a systematic manner through online databases, including Medline, Scopus, Embase, and Google Scholar. Human studies investigating the learning curve of laparoscopic cholecystectomy were included. The Newcastle–Ottawa scale for cohort studies and the GRADE scale were used for the quality assessment of the selected articles. Results: Nine cohort studies published between 1991 and 2020 were included. All studies showed a great heterogeneity among the considered variables. Seven articles (77.7%) assessed intraoperative variables only, without considering patient's characteristics, operator's experience, and grade of gallbladder inflammation. Only five articles (55%) provided a precise cut-off value to see proficiency in the learning curve, ranging from 13 to 200 laparoscopic cholecystectomies. Conclusions: The lack of clear guidelines when evaluating the learning curve in surgery, probably contributed to the divergent data and heterogeneous results among the studies. The development of guidelines for the investigation and reporting of a surgical learning curve would be helpful to obtain more objective and reliable data especially for common operation such as laparoscopic cholecystectomy

    Evaluating alternative fuels for a bus fleet: An Italian case

    Get PDF
    A current topic that has surfaced among Public Transport Companies (PTCs) is the selection of alternative fuels for their bus fleets. Both European and Italian regulations are pushing toward abandoning diesel fuel and the consolidation of alternative traction power sources, such as battery-electric vehicles, fuel-cell electric vehicles, and hydrogen-electric vehicles. The literature has provided some approaches toward assessing this selection such as multicriteria-decision-methods in some countries in the world. However, not enough specific attention has been paid to cost criteria, experts involved, and the type of service required. This paper intends to address these gaps by applying an integrated method, which includes: (i) the Analytical Hierarchy Process (AHP) to define the weights of criteria; (ii) the ELimination Et Choix Traduisant la REalitè I (ELECTRE I) to find a good compromise solution among the fuel alternatives and (iii) a simple Weighted Sum Model (WSM) to refine ranking. This integrated method was applied in Italy involving a panel of experts from whom the data was collected. Different fuel alternatives for both urban and interurban services and with and without funding are discussed. The results provide a useful tool supporting PTC policies, which aims to rationalise and prioritise bus fuel alternatives when deciding on fleet renewal

    Clearance of the mutant androgen receptor in motoneuronal models of spinal and bulbar muscular atrophy.

    Get PDF
    Spinal and bulbar muscular atrophy (SBMA) is an X-linked motoneuron disease caused by an abnormal expansion of a tandem CAG repeat in exon 1 of the androgen receptor (AR) gene that results in an abnormally long polyglutamine tract (polyQ) in the AR protein. As a result, the mutant AR (ARpolyQ) misfolds, forming cytoplasmic and nuclear aggregates in the affected neurons. Neurotoxicity only appears to be associated with the formation of nuclear aggregates. Thus, improved ARpolyQ cytoplasmic clearance, which indirectly decreases ARpolyQ nuclear accumulation, has beneficial effects on affected motoneurons. In addition, increased ARpolyQ clearance contributes to maintenance of motoneuron proteostasis and viability, preventing the blockage of the proteasome and autophagy pathways that might play a role in the neuropathy in SBMA. The expression of heat shock protein B8 (HspB8), a member of the small heat shock protein family, is highly induced in surviving motoneurons of patients affected by motoneuron diseases, where it seems to participate in the stress response aimed at cell protection. We report here that HspB8 facilitates the autophagic removal of misfolded aggregating species of ARpolyQ. In addition, though HspB8 does not influence p62 and LC3 (two key autophagic molecules) expression, it does prevent p62 bodies formation, and restores the normal autophagic flux in these cells. Interestingly, trehalose, a well-known autophagy stimulator, induces HspB8 expression, suggesting that HspB8 might act as one of the molecular mediators of the proautophagic activity of trehalose. Collectively, these data support the hypothesis that treatments aimed at restoring a normal autophagic flux that result in the more efficient clearance of mutant ARpolyQ might produce beneficial effects in SBMA patients

    Effect of atmospheric nitric oxide (NO) on measurements of exhaled NO in asthmatic children

    Get PDF
    The measurement of exhaled nitric oxide concentrations [NO] may provide a simple, noninvasive means for measuring airway inflammation. However, several measurement conditions may influence exhaled NO levels, and ambient NO may be one of these. We measured exhaled NO levels in 47 stable asthmatic children age 5 to 17 years and in 47 healthy children, gender and age matched. Exhaled [NO] in expired air was measured by a tidal breathing method with a chemiluminescence analyzer, sampling at the expiratory side of the mouthpiece. NO steady\u2010state levels were recorded. In order to keep the soft palate closed and avoid nasal contamination, the breathing circuit had a restrictor providing an expiratory pressure of 3\u20134 cm H2O at the mouthpiece. To evaluate the effect of [NO] in ambient air, measurements were randomly performed by breathing ambient air or NO\u2010free air from a closed circuit. Breathing NO\u2010free air, exhaled [NO] in asthmatics (mean \ub1 SEM) was 23.7 \ub1 1.4 ppb, significantly higher (P < 0.001) than in healthy controls (8.7 \ub1 0.4 ppb). Exhaled NO concentrations measured during ambient air breathing were higher (49 \ub1 4.6 ppb, P < 0.001) than when breathing NO\u2010free air (23.7 \ub1 1.4 ppb) and were significantly correlated (r = 0.89, P < 0.001) with atmospheric concentrations of NO (range 3\u2013430 ppb). These findings show that (1) exhaled [NO] values of asthmatic children are significantly higher than in healthy controls, and (2) atmospheric NO levels critically influence the measurement of exhaled [NO]. Therefore, using a tidal breathing method the inhalation of NO\u2010free air during the test is recommended. Pediatr Pulmonol. 1998; 26:30\u201334. \ua9 1998 Wiley\u2010Liss, Inc

    Avaliação da toxicidade da sulfametazina em organismos aquáticos.

    Get PDF
    Resumo: Dentre os fármacos, o grupo dos antibióticos, entre eles as sulfonamidas, é considerado um dos mais importantes. Estes compostos são extensivamente utilizados na medicina humana, veterinária e na aquicultura, com o propósito de prevenir ou tratar infecções microbianas. Essas substâncias podem acumular-se no solo, sofrer lixiviação ou, ainda, ser transportada via escoamento superficial para os corpos hídricos. A fim de alcançar um maior entendimento sobre os efeitos das sulfonamidas, avaliou-se a toxicidade aguda da sulfametazina utilizando-se duas espécies de invertebrados aquáticos (Daphnia similis e Artemia salina) e o peixe (Piaractus mesopotamicus). Foram determinados os valores de concentração efetiva media (CE50-48h), relacionada à imobilidade dos microcrustáceos equivalente a 77,5-48h e >1000 mg L-¹ para D. similis e A. salina, respectivamente. Para o peixe P. mesopotamicus, não houve efeito letal. Considerando-se que estes compostos são administrados em doses elevadas, a avaliação do seu impacto em toda biota aquática parece aconselhável. Os valores, portanto auxiliam para o estabelecimento de concentrações máximas permissíveis de sulfametazina nos corpos de água. Abstract: Among the drugs, the group of antibiotics, including sulfonamides, is considered one of the most important. These compounds are extensively used in human, veterinary medicine and aquaculture, with the purpose of preventing or treating microbial infections. These substances can build up in the soil, leachate or even be transported via superficial runoff to water bodies. In order to achieve a better understanding of the effects of sulfonamides, the acute toxicity of sulfamethazine was evolved using two species of aquatic invertebrates (Daphnia similis and artemia salina) and fish (Piaractus mesopotamicus). Determined the average effective concentration values were (EC50-48h), related to immobility of microcrustaceans equivalent to 77.5-48h and>1000 mg L -1 for D. similis and A. salina, respectively. For the fish P. mesopotamicus not lethal effect was found. Considering that these compounds are administered in high doses, to assess their impact on aquatic biota all seems advisable. values thus help to establish allowable maximum concentrations of sulfamethazine in water bodies

    Isolation and molecular typing of Leishmania infantum from Phlebotomus perfiliewi in a reemerging focus of leishmaniasis, Northeastern Italy

    Get PDF
    Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies collected in a re-emerging focus of VL in the Bologna province. During the summer of 2016, 6114 sand flies were collected, identified, and tested for Leishmania detection. Of the identified sand flies, 96.5% were Phlebotomus (P.) perfiliewi and 3.5% were P. perniciosus. Detected parasites were characterized by biomolecular methods (multilocus microsatellite typing and characterization of repetitive region on chromosome 31), and quantified by real-time PCR. The prevalence of Leishmania infection in individually-tested P. perfiliewi sand flies varied from 6% to 10% with an increasing trend during the season. Promastigotes of L. infantum were isolated by dissection in one P. perfiliewi female; the isolated strain (Lein-pw) were closely related to Leishmania parasites from VL cases in northeastern Italy, but differed from strains isolated in dogs from the same area. Our findings strongly support the vector status of P. perfiliewi for human VL in the study area
    • …
    corecore