399 research outputs found

    Soft commitment: a study on demand and compliance

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    This article explores the demand for soft, self-imposed commitment, and subsequent compliance behaviour, using a framed field study in a higher education setting. We find a substantial soft commitment demand and a remarkably high failure to comply with the chosen commitment.Students are more likely to demand soft commitment if they expect the task to be more time-consuming and their relative performance to be lower. Failure to comply is associated with previous grade and personality traits. We find no evidence that soft commitment affects grades

    A Constructive Heuristics and an Iterated Neighborhood Search Procedure to Solve the Cost-Balanced Path Problem

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    This paper presents a new heuristic algorithm tailored to solve large instances of an NP-hard variant of the shortest path problem, denoted the cost-balanced path problem, recently proposed in the literature. The problem consists in finding the origin–destination path in a direct graph, having both negative and positive weights associated with the arcs, such that the total sum of the weights of the selected arcs is as close to zero as possible. At least to the authors’ knowledge, there are no solution algorithms for facing this problem. The proposed algorithm integrates a constructive procedure and an improvement procedure, and it is validated thanks to the implementation of an iterated neighborhood search procedure. The reported numerical experimentation shows that the proposed algorithm is computationally very efficient. In particular, the proposed algorithm is most suitable in the case of large instances where it is possible to prove the existence of a perfectly balanced path and thus the optimality of the solution by finding a good percentage of optimal solutions in negligible computational time

    Riometry at the Italian Antarctic station of Terra Nova Bay

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    A solid-state riometer has been installed at Terra Nova Bay (74-420S and 164-060E) during the IX Italian Antarctic expedition (1993/1994) to provide, in the frame of the geophysical observatories, studies on the ionospheric absorption in the lower part of the ionosphere. This kind of measurements will integrate the already existing active vertical ionospheric sounding and the magnetic absolute vector observations, with the objective of investigating the state of the ionosphere-magnetosphere coupling. In order to evaluate the base disturbance to the riometer, a remote campaign has been performed at McCarthy Ridge, rather far from the base station, where no anthropic noise is expected. Preliminary data analysis confirms the good quality of the Antarctic riometer observations

    A review of last interglacial sea-level proxies in the western Atlantic and southwestern Caribbean, from Brazil to Honduras

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    We use a standardized template for Pleistocene sea-level data to review last interglacial (Marine Isotope Stage 5 - MIS 5) sea-level indicators along the coasts of the western Atlantic and southwestern Caribbean, on a transect spanning from Brazil to Honduras and including the islands of Aruba, Bonaire, and Curaçao. We identified six main types of sea-level indicators (beach deposits, coral reef terraces, lagoonal deposits, marine terraces, Ophiomorpha burrows, and tidal notches) and produced 55 standardized data points, each constrained by one or more geochronological methods. Sea-level indicators are well preserved along the Brazilian coasts, providing an almost continuous north-to-south transect. However, this continuity disappears north of the Rio Grande do Norte Brazilian state. According to the sea-level index points (discrete past position of relative sea level in space and time) the paleo sea-level values range from ~5.6 to 20m above sea level (a.s.l.) in the continental sector and from ~2 to 10ma.s.l. in the Caribbean islands. In this paper, we address the uncertainties surrounding these values. From our review, we identify that the coasts of northern Brazil, French Guiana, Suriname, Guyana, and Venezuela would benefit from a renewed study of Pleistocene sea-level indicators, as it was not possible to identify sea-level index points for the last interglacial coastal outcrops of these countries. Future research must also be directed at improving the chronological control at several locations, and several sites would benefit from the re-measurement of sea-level index points using more accurate elevation measurement techniques. The database compiled in this study is available in spreadsheet format at the following link: https://doi.org/10.5281/zenodo.5516444 (Version 1.02; Rubio-Sandoval et al., 2021)

    Helminth communities of herons (Aves: Ardeidae) in southern Italy

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    The helminth communities of nine species of herons from southern Italy were studied and compared. Of 24 taxa found including seven digeneans, seven nematodes, six cestodes and four acanthocephalans, only five taxa were found in more than one heron species, and five of the 21 taxa that could be identified to species level were classified as 'heron specialists'. The total number of helminth species per heron species ranged from 1 in Botaurus stellaris to 9 in Ixobrychus minutus with infection levels generally low. A statistical comparison was carried out for herons with a sample size >. 5. At the infracommunity level, only I. minutus clearly differed from other heron species. Diversity parameters of heminth infracommunities did not significantly differ among heron species. Species richness ranged from just 0.3 to 2.3 helminth taxa per individual host, and the Brillouin index, from 0 to 0.3. Total helminth abundance did not exceed 40 worms per host except in a single case of Ardeola ralloides. Infracommunities clearly were dominated by single helminth species. The present study confirms a depauperate helminth community in herons from southern Italy. Comparison with data from Spain and the Czech Republic showed strong quantitative similarities with values obtained in the present study. Results also suggest that the composition of local helminth communities are strongly variable depending on geographical location as is demonstrated by comparison with data from other European areas. However, whether herons in Europe naturally host depauperate helminth communities or these communities are depauperate because of other factors is unknow

    Plasma cells in the carotid plaque: occurrence and significance

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    OBJECTIVE: Atherosclerosis is one of the leading causes of disability and mortality worldwide. Inflammation, including monocytes, T and B cells, plays a key role in its pathogenesis. Our purpose was to evaluate plasma cells’ presence in a large series of carotid artery plaques and the clinical association. PATIENTS AND METHODS: Forty-eight consecutive patients treated with carotid endarterectomy were retrospectively analyzed to assess plasma cells’ presence inside the plaque. A semiquantitative grading score was applied, ranging from absence, scattered, clusters of 5-10, and sheets of >10 plasma cells. Plasma cell’s location, as intraplaque, subendothelial or peri-adventitial, was also defined. RESULTS: In 75% of plaques analyzed, plasma cells were detected: scattered in 63.9%, in clusters in 22.2%, and in sheets in 13.9% of cases. In all cases, plasma cells were observed only inside the plaque. In 13.9% and in 11.1% of cases, plasma cells showed, respectively, a concomitant subendothelial or peri-adventitial distribution. In 5.6% of plaques, there was a simultaneous distribution in subendothelial, peri-adventitial layer, and intraplaque. Association between the presence of symptoms and plasma cells infiltrate was found. CONCLUSIONS: Our results suggest that plasma cells could be a key parameter linked to plaque instability. Some types of configurations are significantly associated with the occurrence of cerebrovascular symptoms

    Association between β2-adrenoceptor (ADRB2) haplotypes and insulin resistance in PCOS

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    OBJECTIVE: The aim of this study was to explore β2-adrenoceptor (ADRB2) haplotype associations with phenotypes and quantitative traits related to insulin resistance (IR) and the metabolic syndrome (MS) in a polycystic ovary syndrome (PCOS) population. A secondary purpose was to assess the association between ADRB2 haplotype and PCOS. DESIGN: Genetic polymorphism analysis. Cross-sectional case-control association study. SETTING: Medical University Hospital and research laboratory. PATIENTS: One hundred and sixty-five unrelated women with PCOS and 116 unrelated women without PCOS (control sample). MEASUREMENTS: Clinical and biochemical measurements, and ADRB2 genotyping in PCOS patients and control subjects. METHODS: ADRB2 haplotypes (comprising rs1042711, rs1801704, rs1042713 and rs1042714 in that order), genotyping and statistical analysis to evaluate associations with continuous variables and traits related to IR and MS in a PCOS population. Associations between ADRB2 haplotypes and PCOS were also assessed. RESULTS: We observed an age-adjusted association between ADRB2 haplotype CCGG and lower insulin (P = 0·018) and HOMA (P = 0·008) in the PCOS sample. Interestingly, the expected differences in surrogate measures of IR between cases and controls were not significant in CCGG/CCGG carriers. In the case-control study, genotype CCGG/CCGG was associated with a 14% decrease in PCOS risk (P = 0·043), taking into account confounding variables. CONCLUSIONS: Haplotype I (CCGG) has a protective role for IR and MS in PCOS.Fil: Tellechea, Mariana Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; ArgentinaFil: Muzzio, Damián Oscar. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; ArgentinaFil: Iglesias Molli, Andrea Elena. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; ArgentinaFil: Belli, Susana H.. Hospital Carlos Durand; ArgentinaFil: Graffigna, Mabel N.. Hospital Carlos Durand; ArgentinaFil: Levalle, Oscar A.. Hospital Carlos Durand; ArgentinaFil: Frechtel, Gustavo Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Cerrone, Gloria Edith. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; Argentin
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