307 research outputs found

    Ordering our world: the quest for traces of temporal organization in autobiographical memory

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    An experiment examined the idea, derived from the Self Memory System model (Conway & Pleydell-Pearce, 2000), that autobiographical events are sometimes tagged in memory with labels reflecting the life era in which an event occurred. The presence of such labels should affect the ease of judgments of the order in which life events occurred. Accordingly, 39 participants judged the order of two autobiographical events. Latency data consistently showed that between-era judgments were faster than within-era judgments, when the eras were defined in terms of either: (a) college versus high school, (b) academic quarter within year, or (c) academic year within school. The accuracy data similarly supported the presence of a between-era judgment effect for the college versus high school dichotomy

    An efficient and traceable KP-ABS scheme with untrusted attribute authority in cloud computing

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    Modificaciones de la microestructura y la capa pasiva de la aleación 2024-T3 Al-Cu durante una limpieza química empleada en la industria aeroespacial

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    Se han investigado los efectos de un pretratamiento superficial empleado en el sector aeroespa-cial sobre la aleación 2024-T3 Al-Cu antes de la generación de recubrimientos por conversión química. Estos pretratamientos influyen en las fases metálicas, que desempeñan un papel clave en el desarrollo de nuevos recu-brimientos de conversión sin cromo y en la susceptibilidad a la corrosión localizada en medios que contienen cloruros. El pretratamiento estudiado consta de dos etapas alcalinas y una ácida. La microscopía electrónica de barrido reveló que después del proceso completo, las fases Al(Cu,Mg) se eliminaban parcial o totalmente medi-ante desaleación y su posterior enriquecimiento de cobre, mientras que solo se atacó la matriz de aluminio que rodeaba las fases Al(Cu,Fe,Mn,Si). El análisis electroquímico reveló el viraje a catódico de las fases Al(Cu,Mg) que aún permanecen en la superficie mientras que la fases Al(Cu,Fe,Mn,Si) presentaron un mayor potencial de corrosión que la matriz de aluminio. Por el contrario, ninguna de estas fases se vio afectada cuando se emplearon únicamente las dos etapas alcalinas. Identificados los procesos que tienen lugar cuando la aleación es sometida a un pretratamiento superficial, es posible diseñar sistemas de protección alternativos a los cromatos.Changes in the microstructure and passive layer of 2024-T3 Al-Cu alloy during a chemical clean-ing employed in the aerospace industry. A standard surface pretreatment for 2024-T3 Al-Cu alloy prior to the generation of chemical conversion coatings in the aerospace sector have been investigated. These pretreatments influence the alloy phases, which play a key role in the development of new eco-friendly chromium-free conver-sion coatings, but also in the susceptibility to localized corrosion in chloride medium. The complete pretreat-ment consists of two alkaline step and another acid step. Scanning Electron Microscopy revealed that after the complete pretreatment, Al(Cu,Mg) phases were partially or totally removed through dealloying with their subsequent copper enrichment, while only the aluminum matrix surrounding the Al(Cu,Fe,Mn,Si) phases was slightly attacked. Electrochemical analysis revealed the turn to cathodic character of Al(Cu,Mg) phases that still remain on the surface, while the Al(Cu,Fe,Mn,Si) phases have a higher corrosion potential than the aluminum matrix. Conversely, none of these phases were affected when only alkaline steps were employed. Identified the corrosion processes that take place in the different phases when the alloy is treated with a surface pretreatment, it is possible to design alternative Cr-free protective proces

    El abandono de los estudios universitarios: factores determinantes y medidas preventivas

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    La deserción de los estudios se ha convertido en un tema importante para la investigación, dado que uno de los retos que tienen plateado la enseñanza universitaria, a nivel mundial, es la puesta en práctica de medidas encaminadas a paliar el efecto negativo de este problema, que afecta de manera directa no sólo a un elevado porcentaje de estudiantes por año, sino también a la propia institución universitaria. En este artículo se presenta una investigación realizada con estudiantes de las 39 titulaciones de la Universidad de La Laguna que habían iniciado sus estudios en el curso 1998-1999, con el objeto de determinar las causas del abandono o prolongación de los estudios. Las variables estudiadas se referían a las características psicoeducativas del alumnado, los hábitos de estudios, las características de la carrera y del profesorado y las características bio-socioeconómicas

    A randomized comparison ofrepeat stenting with balloon angioplasty in patients with in-stent restenosis

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    AbstractObjectivesThis randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR).BackgroundStent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high.MethodsWe randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events.ResultsProcedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 ± 0.4 vs. 2.25 ± 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 ± 0.8 vs. 1.54 ± 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (≥3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting.ConclusionsIn patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome

    Functional classification of DNA variants by hybrid minigenes: identification of 30 spliceogenic variants of BRCA2 exons 17 and 18

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    Mutation screening of the breast cancer genes BRCA1 and BRCA2 identifies a large fraction of variants of uncertain clinical significance (VUS) whose functional and clinical interpretations pose a challenge for genomic medicine. Likewise, an increasing amount of evidence indicates that genetic variants can have deleterious effects on pre-mRNA splicing. Our goal was to investigate the impact on splicing of a set of reported variants of BRCA2 exons 17 and 18 to assess their role in hereditary breast cancer and to identify critical regulatory elements that may constitute hotspots for spliceogenic variants. A splicing reporter minigene with BRCA2 exons 14 to-20 (MGBR2_ ex14-20) was constructed in the pSAD vector. Fiftytwo candidate variants were selected with splicing prediction programs, introduced in MGBR2_ ex14-20 by site-directed mutagenesis and assayed in triplicate in MCF-7 cells. Wild type MGBR2_ ex14-20 produced a stable transcript of the expected size (1,802 nucleotides) and structure (V1-[BRCA2_ exons_ 14-20]-V2). Functional mapping by microdeletions revealed essential sequences for exon recognition on the 3 ' end of exon 17 (c. 79447973) and the 5 ' end of exon 18 (c. 7979-7988, c. 7999-8013). Thirty out of the 52 selected variants induced anomalous splicing in minigene assays with > 16 different aberrant transcripts, where exon skipping was the most common event. A wide range of splicing motifs were affected including the canonical splice sites (15 variants), novel alternative sites (3 variants), the polypyrimidine tract (3 variants) and enhancers/silencers (9 variants). According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), 20 variants could be classified as pathogenic (c. 7806-2A > G, c. 7806-1G > A, c. 7806-1G > T, c. 7806-1_ 7806-2dup, c. 7976+ 1G > A, c. 7977-3_ 7978del, c. 7977-2A > T, c. 7977-1G > T, c. 7977-1G > C, c. 8009C > A, c. 8331+ 1G > T and c. 8331+ 2T > C) or likely pathogenic (c. 78069T > G, c. 7976G > C, c. 7976G > A, c. 7977-7C > G, c. 7985C > G, c. 8023A > G, c. 8035G > T and c. 8331G > A), accounting for 30.8% of all pathogenic/likely pathogenic variants of exons 17-18 at the BRCA Share database. The remaining 8 variants (c. 7975A > G, c. 7977-6T > G, c. 7988A > T, c. 7992T > A, c. 8007A > G, c. 8009C > T, c. 8009C > G, and c. 8072C > T) induced partial splicing anomalies with important ratios of the full-length transcript (>= 70%), so that they remained classified as VUS. Aberrant splicing is therefore especially prevalent in BRCA2 exons 17 and 18 due to the presence of active ESEs involved in exon recognition. Splicing functional assays with minigenes are a valuable strategy for the initial characterization of the splicing outcomes and the subsequent clinical interpretation of variants of any disease-gene, although these results should be checked, whenever possible, against patient RNA

    Anonymity and Rewards in Peer Rating Systems

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    When peers rate each other, they may choose to rate inaccurately in order to boost their own reputation or unfairly lower another’s. This could be successfully mitigated by having a reputation server incentivise accurate ratings with a reward. However, assigning rewards becomes a challenge when ratings are anonymous, since the reputation server cannot tell which peers to reward for rating accurately. To address this, we propose an anonymous peer rating system in which users can be rewarded for accurate ratings, and we formally define its model and security requirements. In our system ratings are rewarded in batches, so that users claiming their rewards only reveal they authored one in this batch of ratings. To ensure the anonymity set of rewarded users is not reduced, we also split the reputation server into two entities, the Rewarder, who knows which ratings are rewarded, and the Reputation Holder, who knows which users were rewarded. We give a provably secure construction satisfying all the security properties required. For our construction we use a modification of a Direct Anonymous Attestation scheme to ensure that peers can prove their own reputation when rating others, and that multiple feedback on the same subject can be detected. We then use Linkable Ring Signatures to enable peers to be rewarded for their accurate ratings, while still ensuring that ratings are anonymous. Our work results in a system which allows for accurate ratings to be rewarded, whilst still providing anonymity of ratings with respect to the central entities managing the system

    Moderate-High Disease Activity in Patients with Recent-Onset Psoriatic Arthritis-Multivariable Prediction Model Based on Machine Learning

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    The aim was to identify patient- and disease-related characteristics predicting moderate-to-high disease activity in recent-onset psoriatic arthritis (PsA). We performed a multicenter observational prospective study (2-year follow-up, regular annual visits) in patients aged ≥18 years who fulfilled the CASPAR criteria and had less than 2 years since the onset of symptoms. The moderate-to-high activity of PsA was defined as DAPSA > 14. We trained a logistic regression model and random forest-type and XGBoost machine learning algorithms to analyze the association between the outcome measure and the variables selected in the bivariate analysis. The sample comprised 158 patients. At the first follow-up visit, 20.8% of the patients who attended the clinic had a moderate-to-severe disease. This percentage rose to 21.2% on the second visit. The variables predicting moderate-high activity were the PsAID score, tender joint count, level of physical activity, and sex. The mean values of the measures of validity of the machine learning algorithms were all high, especially sensitivity (98%; 95% CI: 86.89-100.00). PsAID was the most important variable in the prediction algorithms, reinforcing the convenience of its inclusion in daily clinical practice. Strategies that focus on the needs of women with PsA should be considered
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