El viaje desde los cuestionarios Likert a los cuestionarios de elección forzosa: evidencia de la invarianza de los parámetros de los ítems

Multidimensional forced-choice questionnaires are widely regarded in the personnel selection literature for their ability to control response biases. Recently developed IRT models usually rely on the assumption that item parameters remain invariant when they are paired in forced-choice blocks, without giving it much consideration. This study aims to test this assumption empirically on the MUPP-2PL model, comparing the parameter estimates of the forced-choice format to their graded-scale equivalent on a Big Five personality instrument. The assumption was found to hold reasonably well, especially for the discrimination parameters. In the cases in which it was violated, we briefly discuss the likely factors that may lead to non-invariance. We conclude discussing the practical implications of the results and providing a few guidelines for the design of forced-choice questionnaires based on the invariance assumptionLos cuestionarios de elección forzosa multidimensionales son bastante apreciados en la literatura de selección de personal por su capacidad para controlar los sesgos de respuesta. Los modelos de TRI desarrollados recientemente normalmente asumen que los parámetros de los ítems permanecen invariantes cuando se emparejan en bloques de elección forzosa, sin dedicarle mucha atención. Este estudio tiene como objetivo poner a prueba empíricamente este supuesto en el modelo MUPP-2PL, comparando las estimaciones de los parámetros del formato de elección forzosa con su equivalente en escala graduada, en un instrumento de personalidad Big Five. Se encontró que el supuesto se cumplía razonablemente bien, especialmente para los parámetros de discriminación. En los casos en los que no se cumplió se discuten brevemente los posibles factores que pueden dar lugar a no invarianza. Concluimos discutiendo las implicaciones prácticas de los resultados y proponiendo algunas pautas para el diseño de cuestionarios de elección forzosa basados en el supuesto de invarianzaThis research is funded by the Spanish government’s Ministerio de Economia y Competitividad, projects PSI 2015-65557-P and PSI 2017-85022-

Glasius bio-inspired neural networks based UV-C disinfection path planning improved by preventive deadlock processing algorithm

The COVID-19 pandemic made robot manufacturers explore the idea of combining mobile robotics with UV-C light to automate the disinfection processes. But performing this process in an optimum way introduces some challenges: on the one hand, it is necessary to guarantee that all surfaces receive the radiation level to ensure the disinfection; at the same time, it is necessary to minimize the radiation dose to avoid the damage of the environment. In this work, both challenges are addressed with the design of a complete coverage path planning (CCPP) algorithm. To do it, a novel architecture that combines the glasius bio-inspired neural network (GBNN), a motion strategy, an UV-C estimator, a speed controller, and a pure pursuit controller have been designed. One of the main issues in CCPP is the deadlocks. In this application they may cause a loss of the operation, lack of regularity and high peaks in the radiation dose map, and in the worst case, they can make the robot to get stuck and not complete the disinfection process. To tackle this problem, in this work we propose a preventive deadlock processing algorithm (PDPA) and an escape route generator algorithm (ERGA). Simulation results show how the application of PDPA and the ERGA allow to complete complex maps in an efficient way where the application of GBNN is not enough. Indeed, a 58% more of covered surface is observed. Furthermore, two different motion strategies have been compared: boustrophedon and spiral motion, to check its influence on the performance of the robot navigation

ABCD2 score : análise de recorrências vasculares em doentes com AIT e score ABCD2 <4

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2021Introdução: O score ABCD2 foi desenvolvido para avaliar o risco de recorrência em doentes com acidente isquémico transitório (AIT), sendo que habitualmente doentes com pontuações altas (≥4) são triados para avaliação urgente. Com este estudo procurou-se compreender as limitações da utilização deste score através da análise das recorrências vasculares em doentes com AIT e score ABCD2 <4 Métodos: - Estudo retrospetivo de doentes seguidos na consulta de AIT entre 2004 e 2011. Foram analisadas características demográficas, fatores de risco vascular, clínica e etiologia do AIT, score ABCD2, terapêutica, assim como a ocorrência combinada e individual de AIT, acidente vascular cerebral (AVC), enfarte agudo do miocárdio (EAM) e morte vascular aos 30 dias e 1 ano entre doentes com score ABCD2 <4 e ≥4, assim como em doentes com score ABCD2<4 com e sem recorrências vasculares. Resultados: Incluíram-se 559 doentes – 201 doentes com score ABCD2<4, 349 com score ≥4. Os doentes com score ABCD2<4 apresentaram maior afeção do território vertebro-basilar (46,8% vs. 14,0%, p<0.001). Apresentaram menor risco de recorrência vascular aos 365 dias (9,4% vs. 16,1%, p=0,034); menor risco de AVC aos 30 dias (1,0% vs 4,6%, p=0,044) e aos 365 dias (2,2% vs. 8%, p=0,008). Cerca de 65% das recorrências vasculares nestes doentes ocorreram até aos 30 dias. Embora de forma não significativa, observou-se, adicionalmente, fibrilhação auricular em 4,5% destes doentes, estenose carotídea significativa em 5,0% e estenose intracraniana em 2,5%. Observou-se também maior frequência de AIT’s prévios nos doentes com score ABCD2<4 com recorrências comparativamente aos restantes doentes com score baixo (35,3% vs. 5,4%, p=0,004) Conclusão: Os doentes AIT com score ABCD2<4 baixo apresentaram recorrências vasculares a curto e longo prazo assim como fatores de risco tratáveis associados a maior risco de recorrência. Estudos prospetivos futuros poderão averiguar a importância de AIT’s prévios no risco de recorrência destes doentes.Background: The ABCD2 score was developed to assess the risk of recurrence in patients with transient ischemic attack (TIA), where patients with high scores (≥4) are typically screened for urgent evaluation. This study sought to understand the limitations of this score by analyzing vascular events in patients with TIA and ABCD2 score <4. Methods: Retrospective study of patients followed in the TIA consultation between 2004 and 2011. Demographic characteristics, vascular risk factors, clinical and etiology of TIA, ABCD2 score, treatment, as well as the combined and individual occurrence of TIA, stroke, acute myocardial infarction (MI) and vascular death at 30 days and 1 year were analyzed among patients with an ABCD2 score <4 and ≥4, as well as in patients with an ABCD2 score<4 with and without vascular events. Results: 559 patients were included – 201 patients with an ABCD2 score<4, 349 with a score ≥4. Patients with ABCD2 score<4 had more vertebrobasilar TIAs (46.8% vs. 14.0%, p<0.001). They had a lower risk of vascular events at 365 days (9.4% vs. 16.1%, p=0.034); lower risk of stroke at 30 days (1.0% vs. 4.6%, p=0.044) and at 365 days (2.2% vs. 8%, p=0.008). About 65% of vascular events in these patients occurred within 30 days. Although not significantly, atrial fibrillation was additionally observed in 4.5% of these patients, significant carotid stenosis in 5.0% and intracranial stenosis in 2.5%. A higher frequency of previous TIAs was also observed in patients with an ABCD2 score<4 with recurrences compared to other patients with a low score (35.3% vs. 5.4%, p=0.004) Conclusion: TIA patients with an ABCD2 score <4 had short- and long-term vascular recurrences as well as treatable risk factors associated with increased risk of recurrence. Future prospective studies may investigate the importance of previous TIAs in the risk of recurrence of these patients

Double collinear splitting amplitudes at next-to-leading order

We compute the next-to-leading order (NLO) QCD corrections to the 1 -> 2 splitting amplitudes in different dimensional regularization (DREG) schemes. Besides recovering previously known results, we explore new DREG schemes and analyze their consistency by comparing the divergent structure with the expected behavior predicted by Catani's formula. Through the introduction of scalar-gluons, we show the relation among splittings matrices computed using different schemes. Also, we extended this analysis to cover the double collinear limit of scattering amplitudes in the context of QCD+QED

Perturbative generation of a strange-quark asymmetry in the nucleon

We point out that perturbative evolution in QCD at three loops generates a strange-antistrange asymmetry s(x)-sbar(x) in the nucleon's sea just from the fact that the nucleon has non-vanishing up and down quark valence densities. The recently computed three-loop splitting functions allow for an estimate of this effect. We find that a fairly sizable asymmetry may be generated. Results for analogous asymmetries in the heavy-quark sector are also presented

Collinear splitting, parton evolution and the strange-quark asymmety of the nucleon in NNLO QCD

We consider the collinear limit of QCD amplitudes at one-loop order, and their factorization properties directly in colour space. These results apply to the multiple collinear limit of an arbitrary number of QCD partons, and are a basic ingredient in many higher-order computations. In particular, we discuss the triple collinear limit and its relation to flavour asymmetries in the QCD evolution of parton densities at three loops. As a phenomenological consequence of this new effect, and of the fact that the nucleon has non-vanishing quark valence densities, we study the perturbative generation of a strange--antistrange asymmetry s(x)−s¯(x) in the nucleon's sea

Landsat and local land surface temperatures in a heterogeneous terrain compared to MODIS values

Land Surface Temperature (LST) as provided by remote sensing onboard satellites is a key parameter for a number of applications in Earth System studies, such as numerical modelling or regional estimation of surface energy and water fluxes. In the case of Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra or Aqua, pixels have resolutions near 1 km2 , LST values being an average of the real subpixel variability of LST, which can be significant for heterogeneous terrain. Here, we use Landsat 7 LST decametre-scale fields to evaluate the temporal and spatial variability at the kilometre scale and compare the resulting average values to those provided by MODIS for the same observation time, for the very heterogeneous Campus of the University of the Balearic Islands (Mallorca, Western Mediterranean), with an area of about 1 km2 , for a period between 2014 and 2016. Variations of LST between 10 and 20 K are often found at the sub-kilometre scale. In addition, MODIS values are compared to the ground truth for one point in the Campus, as obtained from a four-component net radiometer, and a bias of 3.2 K was found in addition to a Root Mean Square Error (RMSE) of 4.2 K. An indication of a more elaborated local measurement strategy in the Campus is given, using an array of radiometers distributed in the area

Controlling for response biases in self-report scales: Forced-choice vs. psychometric modeling of likert items

One important problem in the measurement of non-cognitive characteristics such as personality traits and attitudes is that it has traditionally been made through Likert scales, which are susceptible to response biases such as social desirability (SDR) and acquiescent (ACQ) responding. Given the variability of these response styles in the population, ignoring their possible effects on the scores may compromise the fairness and the validity of the assessments. Also, response-style-induced errors of measurement can affect the reliability estimates and overestimate convergent validity by correlating higher with other Likert-scale-based measures. Conversely, it can attenuate the predictive power over non-Likert-based indicators, given that the scores contain more errors. This study compares the validity of the Big Five personality scores obtained: (1) ignoring the SDR and ACQ in graded-scale items (GSQ), (2) accounting for SDR and ACQ with a compensatory IRT model, and (3) using forced-choice blocks with a multi-unidimensional pairwise preference model (MUPP) variant for dominance items. The overall results suggest that ignoring SDR and ACQ offered the worst validity evidence, with a higher correlation between personality and SDR scores. The two remaining strategies have their own advantages and disadvantages. The results from the empirical reliability and the convergent validity analysis indicate that when modeling social desirability with graded-scale items, the SDR factor apparently captures part of the variance of the Agreeableness factor. On the other hand, the correlation between the corrected GSQ-based Openness to Experience scores, and the University Access Examination grades was higher than the one with the uncorrected GSQ-based scores, and considerably higher than that using the estimates from the forced-choice data. Conversely, the criterion-related validity of the Forced Choice Questionnaire (FCQ) scores was similar to the results found in meta-analytic studies, correlating higher with Conscientiousness. Nonetheless, the FCQ-scores had considerably lower reliabilities and would demand administering more blocks. Finally, the results are discussed, and some notes are provided for the treatment of SDR and ACQ in future studiesThis project was partially supported by three grants from the Spanish Ministry of Economy, Industry and Competitiveness (PSI2015-65557-P, PSI2017-85022-P, and FPI BES-2016-077814

Correlates of self-directed behaviors in captive Cercopithecus aethiops

Researchers have widely used self-directed behaviors (SDB) as a behavioral indicator of anxiety in nonhuman primates. We examined if SDB rates in captive vervets (Cercopithecus aethiops) were associated with 1) proximity to conspecifics in general, 2) relative dominance rank of proximity partners, and 3) postconflict situations. Subjects were members of a captive group of vervets at the Lisbon Zoo, Portugal. The group comprised 3 males and 7 females, which were focal sampled for 10.5 h each. Vervets did not engage in more SBD while in proximity of conspecifics than while alone, and individual SDB rates were not generally influenced by dominance ranks of neighbors. Yet, victims of conflicts significantly increased their SDB rates after agonistic episodes, which is consistent with the view that SDB rates are an index of anxiety in Cercopithecus aethiops

Dominância e atracção social num grupo de macacos-verdes (Cercopithecus aethiops) em cativeiro

Dados de interacções de catagem, recolhidos durante quatro meses de observações directas, de um grupo de macacos-vervet (Cercopithecus aethiops) em cativeiro, no Jardim Zoológico de Lisboa, foram utilizados para testar o modelo clássico de Seyfarth (1977) de atracção por indivíduos dominantes. Cada indivíduo foi observado um total de 10.5 horas, através de amostragens focais. Todas as ocorrências de comportamentos agonísticos foram também registadas. A análise dos resultados confirmou que nas fêmeas a catagem é dirigida para cima na hierarquia, apesar de a troca de catagem por apoio agonístico não ser o princípio subjacente a esta atracção. Considerando a teoria dos mercados biológicos, o facto de as díades serem altamente não recíprocas em termos do investimento feito na catagem, parece sugerir que outras comodidades, para além do apoio agonístico, estão a ser trocadas