Search results for "Item"
showing 10 items of 363 documents
Antiparasitic Effect of Stilbene and Terphenyl Compounds against Trypanosoma cruzi Parasites
2021
AbstractBackgroundChagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. No progress in the treatment of this pathology has been made since Nifurtimox was introduced more than fifty years ago and is considered very aggressive and may cause several adverse effects. Currently, this drug has severe limitations, including high frequency of undesirable side effects and limited efficacy and availability and the research to discover new drugs for the treatment of Chagas disease is imperative. Many drugs available in the market are natural products as found in nature or compounds designed based on the str…
Robustified smoothing for enhancement of thermal image sequences affected by clouds
2015
Obtaining radiometric surface temperature information with both high acquisition rate and high spatial resolution is still not possible through a single sensor. However, in several earth observation applications, the fusion of data acquired by different sensors is a viable solution for so called image sharpening. A related issue is the presence of clouds, which may impair the performance of the data fusion algorithms. In this paper we propose a robustified setup for the sharpening of thermal images in a non real-time scenario, capable to deal with missing thermal data due to cloudy pixels, and robust with respect to cloud mask misclassifications. The effectiveness of the presented technique…
Prediction of the difficulty level in a standardized reading comprehension test: contributions from cognitive psychology and psychometrics
2013
This research seeks to identify possible predictors of the difficulty level of reading comprehension items used in a standardized psychometric test for university admission. Several potential predictors of difficulty were proposed, namely, propositional density, negations, grammatical structure, vocabulary difficulty, presence of enhancement elements (words highlighted typographically), item abstraction level and degree of similarity between correct option and relevant text to resolve the item. By Linear Logistic Test Model (Fisher, 1973) it was found that the number of propositions, the syntactic structure, and fundamentally, the presence of difficult words contributed to the prediction of…
Kernel-Based Framework for Multitemporal and Multisource Remote Sensing Data Classification and Change Detection
2008
The multitemporal classification of remote sensing images is a challenging problem, in which the efficient combination of different sources of information (e.g., temporal, contextual, or multisensor) can improve the results. In this paper, we present a general framework based on kernel methods for the integration of heterogeneous sources of information. Using the theoretical principles in this framework, three main contributions are presented. First, a novel family of kernel-based methods for multitemporal classification of remote sensing images is presented. The second contribution is the development of nonlinear kernel classifiers for the well-known difference and ratioing change detectio…
Sub-symbolic Encoding of Words
2003
A new methodology for sub-symbolic semantic encoding of words is presented. The methodology uses the WordNet lexical database and an ad hoc modified Sammon algorithm to associate a vector to each word in a semantic n-space. All words have been grouped according to the WordNet lexicographers’ files classification criteria: these groups have been called lexical sets. The word vector is composed by two parts: the first one, takes into account the belonging of the word to one of these lexical sets; the second one is related to the meaning of the word and it is responsible for distinguishing the word among the other ones of the same lexical set. The application of the proposed technique over all…
How do illiterate adults react to metalinguistic training?
2013
The present study focuses on the capacity of illiterate adults to master three different metalinguistic tasks: judgment of phonological length of words, initial consonant deletion, and lexical segmentation of sentences. Illiterates’ performance, during a pre-test and after training, was compared with that of literates and partial illiterates (adults at the beginning of the process of acquiring literacy) who received the same training. In the pre-test, illiterates were lower than literates in the three tasks; and partial-illiterates were at an intermediate level in two of the tasks. The three groups profited from the training, especially illiterates and partial-illiterates for whom improveme…
Utility of the Mantel-Haenszel Procedure for Detecting Differential Item Functioning in Small Samples
2004
Sample-size restrictions limit the contingency table approaches based on asymptotic distributions, such as the Mantel-Haenszel (MH) procedure, for detecting differential item functioning (DIF) in many practical applications. Within this framework, the present study investigated the power and Type I error performance of empirical and inferential criteria for DIF detection in small samples. Sample sizes (50/50, 100/50, 200/50, and 100/100 for the reference and focal groups, respectively), ability distributions (equal and unequal), and amount of DIF (moderate and high) were manipulated. The results show the advantages of employing theMHchi-square statistic using high levels of significance (•…
Study Protocol—Coping With the Pandemics: What Works Best to Reduce Anxiety and Depressive Symptoms
2021
Background: The coronavirus disease 2019 (COVID-19) pandemic and lockdown might increase anxiety and depressive symptoms in most individuals. Health bodies recommend several coping behaviors to protect against such symptoms, but evidence on the relationship between these behaviors and symptoms mostly comes from cross-sectional studies in convenience samples. We will conduct a prospective longitudinal study of the associations between coping behaviors and subsequent anxiety and depressive symptoms during the COVID-19 pandemic in a representative sample of the Spanish general adult population.Methods: We will recruit 1,000 adult participants from all autonomous communities of Spain and with s…
Cardiac threat appraisal and depression after first myocardial infarction
2012
The present study investigated cardiac threat appraisal and its association with depression after first myocardial infarction (MI). A semi-structured interview allowing for DSM-IV-Axis I diagnoses was administered to 36 patients after first MI. Patients completed self-reports 5 to 15 days after the MI (time 1), 6 to 8 weeks later (time 2) and again 6 months later (time 3). Assessments at time 1 included indices of cardiac threat appraisal, locus of control, coping, and depression while at time 2 and time 3 only measures of depression were obtained. Cardiac threat appraisal was significantly correlated with depression at time 1, but was unrelated to depression scores at time 2 and time 3. Fu…
Contribution to the study of physico-chemical properties of surfaces modified by last treatment : application to the enhancement of localized corrosi…
2011
Metallic materials are more and more used in severe conditions with particularly strong request for improving their behavior in aggressive environment and especially over long periods. The objective of this PhD work is to estimate the potentiality of a laser surface melting treatment on the improvement of the stainless steel 304L corrosion resistance, surface treatments by laser can be revisited on the basis of a recent change in the laser technology. In the frame of this work, a nano-pulsed laser fiber was chosen : it allows the treated surface to be melted for few microns in depth, followed by an ultra-fast solidification occuring with cooling rates up to 1011 K/s. The combination of thes…