Jesús Alvarado - Academia.edu (original) (raw)
Papers by Jesús Alvarado
Frontiers in Psychology, 2021
In the context of multidimensional structures, with the presence of a common factor and multiple ... more In the context of multidimensional structures, with the presence of a common factor and multiple specific or group factors, estimates of reliability require specific estimators. The use of classical procedures such as the alpha coefficient or omega total that ignore structural complexity are not appropriate, since they can lead to strongly biased estimates. Through a simulation study, the bias of six estimators of reliability in multidimensional measures was evaluated and compared. The study is complemented by an empirical illustration that exemplifies the procedure. Results showed that the estimators with the lowest bias in the estimation of the total reliability parameter are omega total, the two versions of greatest lower bound (GLB) and the alpha coefficient, which in turn are also those that produce the highest overestimation of the reliability of the general factor. Nevertheless, the most appropriate estimators, in that they produce less biased estimates of the reliability par...
Clinical Pharmacology & Therapeutics, 2021
Several medications commonly used for a number of medical conditions share a property of function... more Several medications commonly used for a number of medical conditions share a property of functional inhibition of acid sphingomyelinase (ASM), or FIASMA. Preclinical and clinical evidence suggest that the ASM/ceramide system may be central to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. We examined the potential usefulness of FIASMA use among patients hospitalized for severe coronavirus disease 2019 (COVID-19) in an observational multicenter study conducted at Greater Paris University hospitals. Of 2,846 adult patients hospitalized for severe COVID-19, 277 (9.7%) were taking an FIASMA medication at the time of their hospital admission. The primary end point was a composite of intubation and/or death. We compared this end point between patients taking vs. not taking an FIASMA medication in time-to-event analyses adjusted for sociodemographic characteristics and medical comorbidities. The primary analysis was a Cox regression model with inverse probability weighting (IPW). Over a mean follow-up of 9.2 days (SD = 12.5), the primary end point occurred in 104 patients (37.5%) receiving an FIASMA medication, and 1,060 patients (41.4%) who did not. Despite being significantly and substantially associated with older age and greater medical severity, FIASMA medication use was significantly associated with reduced likelihood of intubation or death in both crude (hazard ratio (HR) = 0.71, 95% confidence interval (CI) = 0.58-0.87, P < 0.001) and primary IPW (HR = 0.58, 95%CI = 0.46-0.72, P < 0.001) analyses. This association remained significant in multiple sensitivity analyses and was not specific to one particular FIASMA class or medication. These results show the potential importance of the ASM/ceramide system in COVID-19 and support the continuation of FIASMA medications in these patients. Double-blind controlled randomized clinical trials of these medications for COVID-19 are needed.
Sociological Methods & Research, 2018
The need to determine the correct dimensionality of theoretical constructs and generate valid mea... more The need to determine the correct dimensionality of theoretical constructs and generate valid measurement instruments when underlying items are categorical has generated a significant volume of research in the social sciences. This article presents two studies contrasting different categorical exploratory techniques. The first study compares Mokken scale analysis (MSA) and two-factor-based exploratory techniques for noncontinuous variables: item factor analysis and Normal Ogive Harmonic Analysis Robust Method (NOHARM). Comparisons are conducted across techniques and in reference to the common principal component analysis model using simulated data under conditions of two-dimensionality with different degrees of correlation ( r = .0 to .6). The second study shows the theoretical and practical results of using MSA and NOHARM (the factorial technique which functioned best in the first study) on two nonsimulated data sets. The nonsimulated data are particularly interesting because MSA w...
ABSTRACTObjectiveTo examine the association between dexamethasone use and mortality among hospita... more ABSTRACTObjectiveTo examine the association between dexamethasone use and mortality among hospitalized patients for COVID-19.DesignMulticenter observational retrospective cohort study.SettingGreater Paris University hospitals, France.Participants12,217 adults hospitalized with COVID-19 between 24 January and 20 May 2020, including 171 patients (1.4%) who received dexamethasone orally or by intravenous perfusion during the visit.Data sourceAssistance Publique-Hôpitaux de Paris Health Data Warehouse.Main outcome measuresThe primary endpoint was time to death. We compared this endpoint between patients who received dexamethasone and those who did not in time-to-event analyses adjusting for sex, age, obesity, current smoking status, any medical condition associated with increased COVID-19-related mortality, and clinical and biological severity of COVID-19 at admission, while stratifying by the need of respiratory support (i.e., oxygen or intubation). The primary analysis was a multivari...
The Spanish Journal of Psychology, 2016
This study’s purpose was to analyse basic reading processes in different age groups of Spanish-sp... more This study’s purpose was to analyse basic reading processes in different age groups of Spanish-speaking children using confirmatory factor analysis (CFA) and regression analysis. Two hundred forty-five children (aged 4 years and 9 months, to 9 years and 7 months; 120 boys, 125 girls), native Spanish-speakers, were selected from schools in Madrid. All participants were in either their last year of preschool or the first three years of elementary school, depending on their age. Nine classic reading tasks were created and administered to measure three reading skills: word recognition, phonological awareness, and reading comprehension. The results of the CFA show that data fit to proposed model with a general reading factor based on these three reading skills χ2(27) = 29.03,p= .36, RMSEA = .02, 90% CIs [.0, .05], CFI = 1.0. The word recognition skills were the best at describing reading performance in preschool children (R2= .51 for word identification task); phonological awareness, esp...
Revista Latinoamericana De Psicologia, 2007
Research carried out during the last 50 years has shown that the majority of schooled deafpeople ... more Research carried out during the last 50 years has shown that the majority of schooled deafpeople do not reach the minimal or functional level for written communication. In this article, a review of the investigation attempting to establish the causes and possible solutions for improving reading in deaf children is presented. In particular, we analyze the linguistic components and the signed, phonological and dactylic codes. Finally, we propose a reading model for deaf people; this model is similar to the model proposed for individuals with phonological dyslexia. The following strategies for improving their phonological components are emphasized: dactylology, lip reading, cochlear implants, cued-speech, sign language and kinesthetic stimulation.
AIP Conference Proceedings, 2006
A comparative study was done to investigate the effects of the x-radiation on the electric proper... more A comparative study was done to investigate the effects of the x-radiation on the electric properties of whole human blood, from healthy people. The x-ray source was set to 55 kV and 75 kV, in order to investigate power level effects on the samples. Short and long time effects were also investigated. This experiment used a Solartron spectrometer to obtain the impedance response. No differences were found when samples were studied in the order of days (from one to five days), independently of the power level. Only in the case of 75 kV, in the power of the x-ray source, were detected significant differences between the dielectric properties of the blood, exposed to radiation, and its control sample, provided that the impedance spectrum were registered immediately after the exposure (after 15 or less minutes).
AIP Conference Proceedings, 2006
Dielectric Characterization of Leukocytes from Human Blood. [AIP Conference Proceedings 854, 170 ... more Dielectric Characterization of Leukocytes from Human Blood. [AIP Conference Proceedings 854, 170 (2006)]. Jesús Bernal‐Alvarado, Gilberto Gutiérrez, Antonio Sánchez, Modesto Sosa, Francisco Hernández, Carlos Guerrero ...
Sociological Methods & Research, 2015
This study compares the performance of two approaches in analysing four-point Likert rating scale... more This study compares the performance of two approaches in analysing four-point Likert rating scales with a factorial model: the classical factor analysis (FA) and the item factor analysis (IFA). For FA, maximum likelihood and weighted least squares estimations using Pearson correlation matrices among items are compared. For IFA, diagonally weighted least squares and unweighted least squares estimations using items polychoric correlation matrices are compared. Two hundred and ten conditions were simulated in a Monte Carlo study considering: one to three factor structures (either, independent and correlated in two levels), medium or low quality of items, three different levels of item asymmetry and five sample sizes. Results showed that IFA procedures achieve equivalent and accurate parameter estimates; in contrast, FA procedures yielded biased parameter estimates. Therefore, we do not recommend classical FA under the conditions considered. Minimum requirements for achieving accurate r...
Multivariate Behavioral Research, 2015
Fecha de publicación: NOV 2 2015 Ver información de revista Resumen The current study examines th... more Fecha de publicación: NOV 2 2015 Ver información de revista Resumen The current study examines the performance of the extended unconstrained approach (EXUC) and the latent moderated structural equation modeling procedure (LMS) in situations where quadratic and interaction terms are tested simultaneously and investigates their limitations with regard to the employment of parallel and congeneric measures, relatively low indicator reliabilities, and relatively large numbers of indicators. By means of a Monte Carlo study, we found LMS to be the best option for testing multiple nonlinear effects given sufficient sample size (n 500) and normally distributed exogenous variables. Its advantages became more prominent when indicator reliabilities were heterogeneous and small. The EXUC was a viable option for estimating the model when indicators were parallel and exhibited large indicator reliabilities. An empirical example of the results is provided, and the relevance of measurement model characteristics to assess nonlinear relationships is discussed.
Acta gastroenterologica Latinoamericana, 2008
evidence of gender-related differences in gastric emptying have been reported in the literature. ... more evidence of gender-related differences in gastric emptying have been reported in the literature. Usually, those researches have focusing only with solid or liquid meal and invasive techniques. The objective of this study was to know the differences in the half time of gastric emptying and frequency of peristaltic contractions measured with magnetogastrography (MGG) on healthy subjects, using a semi-solid test meal. the study was carried out in 16 healthy subjects without gastrointestinal disease history they were divided in two groups, 8 male and 8 female. A test meal composed by 250 ml of yogurt and 3 grs of magnetite (Fe3O4), was employed. the gastric emptying half times were found to be 32.3 +/- 10.8 and 36.0 +/- 6.7 minutes, for men and women, respectively. Magnetogastrography modality presented in this study is a useful technique to measure the gastric emptying and the peristaltic contractions frequency. The studies were performed in healthy subjects without side effects. Using...
Cirugía y cirujanos
We undertook this study to describe the results of hepatic orthotopic transplant. Patient charact... more We undertook this study to describe the results of hepatic orthotopic transplant. Patient characteristics, implants, and patient evolution after transplant were studied. The study was conducted at a third-level medical facility in Mexico. The files of 49 patients who had a liver transplant were reviewed from July 17, 1999, through November 30, 2006. We also analyzed pretransplant status and status of the hepatic implant at the time of the transplant. Finally, patient evolution was reported postoperatively. Fifty transplants were carried out in 49 patients (one man was retransplanted and one women had a liver and kidney transplant). There were 35 women (71.43%) and 14 men (28.57%). Ages of the patients were between 2 and 61 years (average 40.40 years). The most frequent causes resulting in transplants were cirrhosis caused by hepatitis C virus (HCV) and autoimmune cirrhosis: 28 cases (56%) and 7 cases (14%), respectively. Four patients (8%) died from surgery-related complications and...
Procedia - Social and Behavioral Sciences, 2012
Cirugía y …, 2007
2007 Federico Mendoza Sánchez / Francisco Javier Haro Haro / Jesús Sandoval Alvarado / Alonso Zep... more 2007 Federico Mendoza Sánchez / Francisco Javier Haro Haro / Jesús Sandoval Alvarado / Alonso Zepeda González / Roberto Herrera Rodríguez / Ángel Bassols Ricardez TRASPLANTE HEPÁTICO ORTOTÓPICO. RESULTADOS EN UN CENTRO DE TRASPLANTES Cirugía ...
Frontiers in Psychology, 2021
In the context of multidimensional structures, with the presence of a common factor and multiple ... more In the context of multidimensional structures, with the presence of a common factor and multiple specific or group factors, estimates of reliability require specific estimators. The use of classical procedures such as the alpha coefficient or omega total that ignore structural complexity are not appropriate, since they can lead to strongly biased estimates. Through a simulation study, the bias of six estimators of reliability in multidimensional measures was evaluated and compared. The study is complemented by an empirical illustration that exemplifies the procedure. Results showed that the estimators with the lowest bias in the estimation of the total reliability parameter are omega total, the two versions of greatest lower bound (GLB) and the alpha coefficient, which in turn are also those that produce the highest overestimation of the reliability of the general factor. Nevertheless, the most appropriate estimators, in that they produce less biased estimates of the reliability par...
Clinical Pharmacology & Therapeutics, 2021
Several medications commonly used for a number of medical conditions share a property of function... more Several medications commonly used for a number of medical conditions share a property of functional inhibition of acid sphingomyelinase (ASM), or FIASMA. Preclinical and clinical evidence suggest that the ASM/ceramide system may be central to severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection. We examined the potential usefulness of FIASMA use among patients hospitalized for severe coronavirus disease 2019 (COVID-19) in an observational multicenter study conducted at Greater Paris University hospitals. Of 2,846 adult patients hospitalized for severe COVID-19, 277 (9.7%) were taking an FIASMA medication at the time of their hospital admission. The primary end point was a composite of intubation and/or death. We compared this end point between patients taking vs. not taking an FIASMA medication in time-to-event analyses adjusted for sociodemographic characteristics and medical comorbidities. The primary analysis was a Cox regression model with inverse probability weighting (IPW). Over a mean follow-up of 9.2 days (SD = 12.5), the primary end point occurred in 104 patients (37.5%) receiving an FIASMA medication, and 1,060 patients (41.4%) who did not. Despite being significantly and substantially associated with older age and greater medical severity, FIASMA medication use was significantly associated with reduced likelihood of intubation or death in both crude (hazard ratio (HR) = 0.71, 95% confidence interval (CI) = 0.58-0.87, P < 0.001) and primary IPW (HR = 0.58, 95%CI = 0.46-0.72, P < 0.001) analyses. This association remained significant in multiple sensitivity analyses and was not specific to one particular FIASMA class or medication. These results show the potential importance of the ASM/ceramide system in COVID-19 and support the continuation of FIASMA medications in these patients. Double-blind controlled randomized clinical trials of these medications for COVID-19 are needed.
Sociological Methods & Research, 2018
The need to determine the correct dimensionality of theoretical constructs and generate valid mea... more The need to determine the correct dimensionality of theoretical constructs and generate valid measurement instruments when underlying items are categorical has generated a significant volume of research in the social sciences. This article presents two studies contrasting different categorical exploratory techniques. The first study compares Mokken scale analysis (MSA) and two-factor-based exploratory techniques for noncontinuous variables: item factor analysis and Normal Ogive Harmonic Analysis Robust Method (NOHARM). Comparisons are conducted across techniques and in reference to the common principal component analysis model using simulated data under conditions of two-dimensionality with different degrees of correlation ( r = .0 to .6). The second study shows the theoretical and practical results of using MSA and NOHARM (the factorial technique which functioned best in the first study) on two nonsimulated data sets. The nonsimulated data are particularly interesting because MSA w...
ABSTRACTObjectiveTo examine the association between dexamethasone use and mortality among hospita... more ABSTRACTObjectiveTo examine the association between dexamethasone use and mortality among hospitalized patients for COVID-19.DesignMulticenter observational retrospective cohort study.SettingGreater Paris University hospitals, France.Participants12,217 adults hospitalized with COVID-19 between 24 January and 20 May 2020, including 171 patients (1.4%) who received dexamethasone orally or by intravenous perfusion during the visit.Data sourceAssistance Publique-Hôpitaux de Paris Health Data Warehouse.Main outcome measuresThe primary endpoint was time to death. We compared this endpoint between patients who received dexamethasone and those who did not in time-to-event analyses adjusting for sex, age, obesity, current smoking status, any medical condition associated with increased COVID-19-related mortality, and clinical and biological severity of COVID-19 at admission, while stratifying by the need of respiratory support (i.e., oxygen or intubation). The primary analysis was a multivari...
The Spanish Journal of Psychology, 2016
This study’s purpose was to analyse basic reading processes in different age groups of Spanish-sp... more This study’s purpose was to analyse basic reading processes in different age groups of Spanish-speaking children using confirmatory factor analysis (CFA) and regression analysis. Two hundred forty-five children (aged 4 years and 9 months, to 9 years and 7 months; 120 boys, 125 girls), native Spanish-speakers, were selected from schools in Madrid. All participants were in either their last year of preschool or the first three years of elementary school, depending on their age. Nine classic reading tasks were created and administered to measure three reading skills: word recognition, phonological awareness, and reading comprehension. The results of the CFA show that data fit to proposed model with a general reading factor based on these three reading skills χ2(27) = 29.03,p= .36, RMSEA = .02, 90% CIs [.0, .05], CFI = 1.0. The word recognition skills were the best at describing reading performance in preschool children (R2= .51 for word identification task); phonological awareness, esp...
Revista Latinoamericana De Psicologia, 2007
Research carried out during the last 50 years has shown that the majority of schooled deafpeople ... more Research carried out during the last 50 years has shown that the majority of schooled deafpeople do not reach the minimal or functional level for written communication. In this article, a review of the investigation attempting to establish the causes and possible solutions for improving reading in deaf children is presented. In particular, we analyze the linguistic components and the signed, phonological and dactylic codes. Finally, we propose a reading model for deaf people; this model is similar to the model proposed for individuals with phonological dyslexia. The following strategies for improving their phonological components are emphasized: dactylology, lip reading, cochlear implants, cued-speech, sign language and kinesthetic stimulation.
AIP Conference Proceedings, 2006
A comparative study was done to investigate the effects of the x-radiation on the electric proper... more A comparative study was done to investigate the effects of the x-radiation on the electric properties of whole human blood, from healthy people. The x-ray source was set to 55 kV and 75 kV, in order to investigate power level effects on the samples. Short and long time effects were also investigated. This experiment used a Solartron spectrometer to obtain the impedance response. No differences were found when samples were studied in the order of days (from one to five days), independently of the power level. Only in the case of 75 kV, in the power of the x-ray source, were detected significant differences between the dielectric properties of the blood, exposed to radiation, and its control sample, provided that the impedance spectrum were registered immediately after the exposure (after 15 or less minutes).
AIP Conference Proceedings, 2006
Dielectric Characterization of Leukocytes from Human Blood. [AIP Conference Proceedings 854, 170 ... more Dielectric Characterization of Leukocytes from Human Blood. [AIP Conference Proceedings 854, 170 (2006)]. Jesús Bernal‐Alvarado, Gilberto Gutiérrez, Antonio Sánchez, Modesto Sosa, Francisco Hernández, Carlos Guerrero ...
Sociological Methods & Research, 2015
This study compares the performance of two approaches in analysing four-point Likert rating scale... more This study compares the performance of two approaches in analysing four-point Likert rating scales with a factorial model: the classical factor analysis (FA) and the item factor analysis (IFA). For FA, maximum likelihood and weighted least squares estimations using Pearson correlation matrices among items are compared. For IFA, diagonally weighted least squares and unweighted least squares estimations using items polychoric correlation matrices are compared. Two hundred and ten conditions were simulated in a Monte Carlo study considering: one to three factor structures (either, independent and correlated in two levels), medium or low quality of items, three different levels of item asymmetry and five sample sizes. Results showed that IFA procedures achieve equivalent and accurate parameter estimates; in contrast, FA procedures yielded biased parameter estimates. Therefore, we do not recommend classical FA under the conditions considered. Minimum requirements for achieving accurate r...
Multivariate Behavioral Research, 2015
Fecha de publicación: NOV 2 2015 Ver información de revista Resumen The current study examines th... more Fecha de publicación: NOV 2 2015 Ver información de revista Resumen The current study examines the performance of the extended unconstrained approach (EXUC) and the latent moderated structural equation modeling procedure (LMS) in situations where quadratic and interaction terms are tested simultaneously and investigates their limitations with regard to the employment of parallel and congeneric measures, relatively low indicator reliabilities, and relatively large numbers of indicators. By means of a Monte Carlo study, we found LMS to be the best option for testing multiple nonlinear effects given sufficient sample size (n 500) and normally distributed exogenous variables. Its advantages became more prominent when indicator reliabilities were heterogeneous and small. The EXUC was a viable option for estimating the model when indicators were parallel and exhibited large indicator reliabilities. An empirical example of the results is provided, and the relevance of measurement model characteristics to assess nonlinear relationships is discussed.
Acta gastroenterologica Latinoamericana, 2008
evidence of gender-related differences in gastric emptying have been reported in the literature. ... more evidence of gender-related differences in gastric emptying have been reported in the literature. Usually, those researches have focusing only with solid or liquid meal and invasive techniques. The objective of this study was to know the differences in the half time of gastric emptying and frequency of peristaltic contractions measured with magnetogastrography (MGG) on healthy subjects, using a semi-solid test meal. the study was carried out in 16 healthy subjects without gastrointestinal disease history they were divided in two groups, 8 male and 8 female. A test meal composed by 250 ml of yogurt and 3 grs of magnetite (Fe3O4), was employed. the gastric emptying half times were found to be 32.3 +/- 10.8 and 36.0 +/- 6.7 minutes, for men and women, respectively. Magnetogastrography modality presented in this study is a useful technique to measure the gastric emptying and the peristaltic contractions frequency. The studies were performed in healthy subjects without side effects. Using...
Cirugía y cirujanos
We undertook this study to describe the results of hepatic orthotopic transplant. Patient charact... more We undertook this study to describe the results of hepatic orthotopic transplant. Patient characteristics, implants, and patient evolution after transplant were studied. The study was conducted at a third-level medical facility in Mexico. The files of 49 patients who had a liver transplant were reviewed from July 17, 1999, through November 30, 2006. We also analyzed pretransplant status and status of the hepatic implant at the time of the transplant. Finally, patient evolution was reported postoperatively. Fifty transplants were carried out in 49 patients (one man was retransplanted and one women had a liver and kidney transplant). There were 35 women (71.43%) and 14 men (28.57%). Ages of the patients were between 2 and 61 years (average 40.40 years). The most frequent causes resulting in transplants were cirrhosis caused by hepatitis C virus (HCV) and autoimmune cirrhosis: 28 cases (56%) and 7 cases (14%), respectively. Four patients (8%) died from surgery-related complications and...
Procedia - Social and Behavioral Sciences, 2012
Cirugía y …, 2007
2007 Federico Mendoza Sánchez / Francisco Javier Haro Haro / Jesús Sandoval Alvarado / Alonso Zep... more 2007 Federico Mendoza Sánchez / Francisco Javier Haro Haro / Jesús Sandoval Alvarado / Alonso Zepeda González / Roberto Herrera Rodríguez / Ángel Bassols Ricardez TRASPLANTE HEPÁTICO ORTOTÓPICO. RESULTADOS EN UN CENTRO DE TRASPLANTES Cirugía ...