Multivariate Statistical Techniques: A New Approach to Identify the Commercial Properties of Mixtures of Flours of Lentinula edodes and Cocoa Pod Husk.

Lentinula edodes is known to show high nutritional and organoleptic properties and can be mixed with different by-products in the production of new foods with important functional characteristics. Cocoa pod husk (CPH) is the main by-product in the cocoa industry and presents important bioactivities. In this research, two mixtures were applied based on Lentinula edodes mushroom flour from fifty different strains (strain 1 to strain 50) and cocoa pod husk flour (CPHF): 60% Lentinula edodes mushroom flour from each strain mixed with 40% CPHF (Mixture 1), and 80% Lentinula edodes mushroom flour from each strain mixed with 20% CPHF (Mixture 2). The parameters evaluated were moisture, proteins, fat, total dietary fiber (TDF), ash, carbohydrates, antioxidant capacity, antimicrobial activity, pH and water activity (aw). The multivariate statistical techniques evaluated those samples that exhibited the highest degree of correlation with the distinct chemical and commercial parameters, showing that sample 13 of both mixture flours (M1 and M2) obtained by the mushrooms of L. edodes (strain 13) with CPH indicated the higher significant of the parameters. In addition, the sensory test of the best flour (sample 13) was applied to 50 panelists, presenting the best sensory characteristics, such as color, aroma, texture and general acceptability.

New cut-off points of PHQ-9 and its variants, in Costa Rica: a nationwide observational study.

The PHQ-9 questionnaire is a screening test worldwide used to measure depression. But it cannot be used in Costa Rica, due to the fact that it has not previously been validated for its population. The present study aims to show the validation of the PHQ-9 questionnaire and its variants (PHQ-2, PHQ-4, PHQ-8) in a population sample of adults residing in Costa Rica. A sample was collected (n = 1162) using a self-administered questionnaire. Confirmatory Factor Analysis (CFA), Receiver Operating Characteristic (ROC) curve, and Multiple Group Confirmatory Factor Analysis (MGCFA) were tested. One factor was found that explained 73.33% of the variance with excellent internal consistency (α = 0.928). Goodness-of-fit measures were adequate (RMSEA = 0.107; CFI = 0.948), as was diagnostic power at a cut-off of 10 (78.60 for Sensitivity and 27.95 for 1-Specificity). External validation indices were good (r = 0.843 with GAD-7, r = - 0.647 with RS14, and r = 0.301 with FCV19S), and the model showed invariance by sex (∆χ2 = 27.90; df = 27; p < 0.001). Additionally, new cut-off points were proposed for PHQ-9 and its variants for Costa Rican male, female, and general populations. The PHQ-9 and its variants (PHQ-2, 4, and 8) are valid tools for detecting depression (and anxiety for PHQ-4) in Costa Rican population. In addition, new cut-off points differentiated by sex are proposed.

STATIS multivariate three-way method for evaluating quality of life after corneal surgery: Methodology and case study in Costa Rica.

Vision-related quality of life (QoL) analyzes the visual function concerning individual well-being based on activity and social participation. Because QoL is a multivariate construct, a multivariate statistical method must be used to analyze this construct. In this paper, we present a methodology based on STATIS multivariate three-way methods to assess the real change in vision-related QoL for myopic patients by comparing their conditions before and after corneal surgery. We conduct a case study in Costa Rica to detect the outcomes of patients referred for myopia that underwent refractive surgery. We consider a descriptive, observational and prospective study. We utilize the NEI VFQ-25 instrument to measure the vision-related QoL in five different stages over three months. After applying this instrument/questionnaire, a statistically significant difference was detected between the perceived QoL levels. In addition, strong correlations were identified with highly similar structures ranging from 0.857 to 0.940. The application of the dual STATIS method found the non-existence of reconceptualization in myopic patients, but a statistically significant recalibration was identified. Furthermore, a real change was observed in all patients after surgery. This finding has not been stated previously due to the limitations of the existing statistical tools. We demonstrated that dual STATIS is a multivariate method capable of evaluating vision-related QoL data and detecting changes in recalibration and reconceptualization.

A reproducible and repeatable digital method for quantifying nasal and sinus airway changes following suture palatine expansion.

PURPOSE: The airway complex is modified by palatine expansion. Computer tomography has been used in the past to determine the change in volume, but there was a lack of a specific, reproducible method for this purpose. The present study sought to determine the accuracy, reproducibility, and repeatability of an innovative digital measurement technique for analyzing the volume of maxillary and nasal sinus airways following suture palatine expansion performed with the Hyrax disyuntor appliance. METHODS: Patients underwent preoperative and postoperative cone-beam computed tomography (CBCT) scans. The datasets were subsequently uploaded into a digital treatment planning software to record the volume of the right and left maxillary sinus, as well as the nasal and maxillary sinus airway complex. The Gage Repeatability & Reproducibility statistical analysis methodology was used to evaluate the repeatability and reproducibility of this measurement technique when measuring the volume of maxillary and nasal sinus airways following suture palatine expansion with the Hyrax disyuntor appliance. Additionally, comparative analysis between preoperative and postoperative measures was performed using Student's t-test for statistical analysis. RESULTS: In 5 patients, paired t-tests found statistically significant differences before and after treatment in the volumes of the left maxillary sinus (p = 0.002), right maxillary sinus (p = 0.001), and nasal and maxillary sinus airway complex (p = 0.005) after suture palatine expansion with the Hyrax disyuntor appliance. CONCLUSION: The proposed digital technique is an accurate, repeatable, and reproducible measurement technique for analyzing the volume of maxillary and nasal sinus airways following suture palatine expansion using the Hyrax disyuntor.

Effectiveness and types of interventions to reduce mental illness-related stigma among Medical university students: A literature review (1997-2020).

There is a high prevalence of stigma among medical students towards mental illness, which can have far reaching negative consequences. It is essential to intervene and modify their preconceptions in order to fight against stigma.

Eficacia y tipos de intervencionespara reducir el estigma hacia laenfermedad mental en estudiantesuniversitarios de Medicina: Unarevisión de la literatura (1997-2020) / Effectiveness and types of interventions to reduce mental illness-related stigma among medical university students: A literature review (1997-2020)

Entre los estudiantes de MEDICINA existe una alta prevalencia de estigma hacia la enfermedad mental, lo que puedeprovocar consecuencias negativas de gran alcance. Es de suma importancia intervenir y modificar las cogniciones en los futuros médicos para luchar contra el estigma. El objetivo de este trabajo es describir los tipos y la efectividad de las intervenciones para la reducción del estigma hacia las enfermedades mentales entre los estudiantes de MEDICINA a través de una revisión de la literatura existente de 1997 a 2020. Se realizó una búsqueda sistemática en las bases de datos PubMed, Web of Science (WOS) y Cochrane Library según la metodología PRISMA. Se localizaron un total de 87 manuscritos, tras la lectura de sus resúmenes se procedió a la exclusión de 49 por no adaptarse a los parámetros de estudio. Se seleccionaron 38 documentos que cumplían con los criterios de inclusión y 6 añadidos de búsquedas relacionales. Se evaluaron 44 estudios con una participación de global de 20.196 estudiantes de MEDICINA. En el 97 % de los casos las metodologías de intervención de reducción de estigma fueron eficaces. Se hallaron 16 tipos de intervenciones diferentes que presentan alta heterogeneidad metodológica. Las intervenciones aplicadas para la reducción del estigma hacia las enfermedades mentales (EM) entre los estudiantes de MEDICINA demuestran efectividad prácticamente en su mayoría. Las prácticas educativas son las más eficaces a largo plazo y junto con la comprensión médica positiva, la búsqueda de ayuda y el contacto experiencial en vivo, se presentan como fuertes estrategias de combate hacia las actitudes estigmatizantes.(AU)

objective of this study is to describe the types and effectiveness of interventions to reduce mental illness-related stigmaamong medical university students through a review of theliterature published from 1997 to 2020. A systematic searchwas carried out in the following databases: PubMed, Web ofScience (WOS) and Cochrane Library, following the PRISMAmethodology. After the search, 87 manuscripts were found.49 documents met the selection criteria, and 6 additional texts were included after a search for related studies. 44studies were assessed, with a global participation of 20.196Medicine students. In 97% of the cases, the methods of intervention for the reduction of stigma towards mental disorders (TM)were effective. 16 different types of interventions were found, with a limited number of methodologies.Teaching practices are the most effective in the long-term,together with a positive medical understanding, the searchfor help and the in vivo experiential contact, which are presented as strong strategies to combat stigmatizing attitudes.(AU)

Detection of response shift in health-related quality of life studies: a systematic review.

BACKGROUND: Response Shift (RS) refers to the idea that an individual may undergo changes in its health-related quality of life (HRQOL). If internal standard, values, or reconceptualization of HRQOL change over time, then answer to the same items by the same individuals may not be comparable over time. Traditional measures to evaluate RS is prone to bias and strong methodologies to study the existence of this phenomenon is required. The objective is to systematically identify, analyze, and synthesize the existing and recent evidence of statistical methods used for RS detection in HRQOL studies. METHODS: The analysis of selected studies between January 2010 and July 2020 was performed through a systematic review in MEDLINE/PubMed, Scopus, Web of Science, PsycINFO and Google Scholar databases. The search strategy used the terms "Health-Related Quality of Life" and "Response Shift" using the filters "Humans", "Journal Article", "English" and "2010/01/01-2020/07/31". The search was made in August 2020. RESULTS: After considering the inclusion and exclusion criteria, from the total selected articles (675), 107 (15.9%) of the publications were included in the analysis. From these, 79 (71.0%) detected the existence of RS and 86 (80.4%) only used one detection method. The most used methods were Then Test (n = 41) and Oort's Structural Equation Models (SEM) (n = 35). Other method used were Multiple Lineal Regression (n = 7), Mixed-Effect Regression (n = 6), Latent Trajectory Analysis (n = 6), Item Response Theory (n = 6), Logistics Regression (n = 5), Regression and Classification Trees (n = 4) and Relative Importance Method (n = 4). Most of these detected recalibration, including Then Test (n = 27), followed by Oort's SEM that detected the higher combination of RS types: recalibration (n = 24), reprioritization (n = 13) and reconceptualization (n = 7). CONCLUSIONS: There is a continuous interest of studying RS detection. Oort's SEM becomes the most versatile method in its capability for detecting RS in all different types. Despite results from previous systematic reviews, same methods have been used during the last years. We observed the need to explore other alternative methods allowing same detection capacity with robust and highly precise methodology. The investigation on RS detection and types requires more study, therefore new opportunity grows to continue attending this phenomenon through a multidisciplinary perspective.

Pain Experienced during Various Dental Procedures: Clinical Trial Comparing the Use of Traditional Syringes with the Controlled-Flow Delivery Dentapen® Technique.

Background and Objectives: Currently, one of the most discouraging aspects for many patients undergoing dental procedures is the administration of anaesthesia. Consequently, there is a constant search for new techniques to avoid the invasive and painful nature of the injection. A new motorised syringe system (Dentapen®) has recently been developed, standing out for its convenience and ease of use. Material and Methods: Randomised, controlled, single-blind, and single-centre study including 178 voluntary adult participants aged between 18 and 90 years. Individuals were randomly assigned using a randomised table. Patients were asked to rate the level of pain experienced during the injections, using a 10-point visual analogue scale (VAS). The following data were recorded: pain index, heart rate, blood pressure, and saturation, both before and after anaesthesia. Results: Of the total 178 participants, 87 participants (48.9%) were men and 91 (51.1%) were women. The first variable to be assessed was the pain experienced by patients when anaesthetised with a syringe, obtaining a mean value of 2.63 ± 1.86 on the VAS with the conventional syringe and 1.06 ± 1.28 with the Dentapen® syringe, showing statistically significant differences (p-value < 0.01). When stratifying, based on the procedure that was undertaken, differences were also significant for all treatments (p-value < 0.01) except for endodontics, where differences were likely to be significant (p-value = 0.02). Conclusions: In conclusion, from a clinical standpoint, the Dentapen® syringe is a valid alternative to traditional infiltration syringes, causing minimum pain with the injection.

Data-Mining Techniques: A New Approach to Identifying the Links among Hybrid Strains of Pleurotus with Culture Media.

In this study, a data set of mycelial and cultural characteristics of hybrid strains of Pleurotus ostreatus and Pleurotus djamor were analyzed using three data-mining techniques: the K-medoids clustering algorithm, PCA biplot and the association rules algorithm. The characteristics evaluated were as follows: maximum velocity; lag phase; biomass; and exopolysaccharides content in the cultivation of 50 hybrid strains of Pleurotus ostreatus and 50 hybrid strains of Pleurotus djamor. Different mixtures of culture media were used to supplement Ecuadorian agricultural products. Data of the parameters obtained in the experimental methods were grouped into four clusters, obtaining a presentation of the hybrid strains of Pleurotus with a higher relation to each characteristic measured. Data-mining tools showed the hybrid strains cultivated on solid-culture media (M1 = malt extract agar and rice flour) and liquid-culture media (L1 = maltose, yeast extract and rice flour) presented the highest mycelial and cultural characteristics. These results are good indicators to improve the industrial production of edible fungi by using rice flour in the cultivation, contributing to the mushroom market and circular economy.

Application of K-Means Clustering Algorithm to Commercial Parameters of Pleurotus spp. Cultivated on Representative Agricultural Wastes from Province of Guayas.

Data of the commercial parameters of Pleurotus ostreatus and Pleurotus djamor were analyzed using the data mining technique: K-means clustering algorithm. The parameters evaluated were: biological efficiency, crop yield ratio, productivity rate, nutritional composition, antioxidant and antimicrobial activities in the production of fruit bodies of 50 strains of Pleurotus ostreatus and 50 strains of Pleurotus djamor, cultivated on the most representative agricultural wastes from the province of Guayas: 80% sugarcane bagasse and 20% wheat straw (M1), and 60% wheat straw and 40% sugarcane bagasse (M2). The database of the parameters obtained in experimental procedures was grouped into three clusters, providing a visualization of the strains with a higher relation to each parameter (vector) measured.

Childhood wheezing phenotypes and their association to perinatal factors: a longitudinal study.

INTRODUCTION: Multiple gestational and early life factors have been described as the variables that increase the risk for each phenotype of infantile wheezing. Our objective was to study the evolution of wheezing in a cohort of children followed up to 9-10 years of age and its relationship with different perinatal risk factors. METHODS: A longitudinal study was made on the evolution of wheezing, over time, in 1164 children from Salamanca (Spain) included in the International Study of Wheezing in Infants, when the children were 12 months old. They were classified into three phenotypes: transient early wheezing (last episode before 3 years of age), early persistent wheezing (start before 3 years age and persisting thereafter), and late-onset wheezing (first episode after 3 years of age). Univariate and multivariable analyses were performed to establish associations between the different phenotypes and perinatal factors. RESULTS: Data were obtained corresponding to a total of 531 children. Of these, 169 (31.8%) had experienced transient early wheezing, 100 (18.8%) early persistent wheezing, 28 (5.3%) late-onset wheezing, and 234 (44.1%) had never experienced wheezing. Cesarean delivery, early exposure to infections, the presence of atopic eczema, and a smoking father were associated with transient early wheezing. Early persistent wheezing was associated with a family history of allergy, smoking, and obstetric diseases. Exclusive breastfeeding was identified as a protective factor in both transient and persistent early wheezing. Late-onset wheezing was associated with the male gender and with maternal history of rhinitis and eczema. CONCLUSIONS: Wheezing phenotypes were associated with different risk perinatal factors. Knowledge in the field is essential in order to influence the modifiable factors.

Childhood wheezing phenotypes and their association to perinatal factors: a longitudinal study

Introduction: Multiple gestational and early life factors have been described as the variables that increase the risk for each phenotype of infantile wheezing. Our objective was to study the evolution of wheezing in a cohort of children followed up to 9–10 years of age and its relationship with different perinatal risk factors. Methods: A longitudinal study was made on the evolution of wheezing, over time, in 1164 children from Salamanca (Spain) included in the International Study of Wheezing in Infants, when the children were 12 months old. They were classified into three phenotypes: transient early wheezing (last episode before 3 years of age), early persistent wheezing (start before 3 years age and persisting thereafter), and late-onset wheezing (first episode after 3 years of age). Univariate and multivariable analyses were performed to establish associations between the different phenotypes and perinatal factors. Results: Data were obtained corresponding to a total of 531 children. Of these, 169 (31.8%) had experienced transient early wheezing, 100 (18.8%) early persistent wheezing, 28 (5.3%) late-onset wheezing, and 234 (44.1%) had never experienced wheezing. Cesarean delivery, early exposure to infections, the presence of atopic eczema, and a smoking father were associated with transient early wheezing. Early persistent wheezing was associated with a family history of allergy, smoking, and obstetric diseases. Exclusive breastfeeding was identified as a protective factor in both transient and persistent early wheezing. Late-onset wheezing was associated with the male gender and with maternal history of rhinitis and eczema (AU)

Age Related Changes in the Executive Function of Colombian Children / Cambios relacionados con la edad en las Funciones Ejecutivas de niños colombianos

Executive Function (EF) is a higher cognitive process responsible for control and self-regulation of behavior. The aim of this study is to describe the developmental trajectory of EF in four and six-year old Colombian children, and to highlight possible differences by socio-cultural variables such as age, sex, type of school or socio-economic status. One hundred and sixty-three normotypical children were tested using psychological tests validated for a Spanish population belonging to the Weschler and Luria Initial batteries. HJ-biplot analysis showed that EF developed commensurate with age and school grade, although differences by socioeconomic status and type of school were evident.

Las funciones ejecutivas (FE) son un proceso cognitivo superior para la autorregulación y control del comportamiento. El objetivo del estudio fue describir las trayectorias de desarrollo de 163 niños colombianos normotípicos de 4 y 6 años de edad y resaltar las diferencias observadas según variables sociodemográficas como edad, sexo, tipo de colegio y condición socioeconómica. Para ello, se aplicaron pruebas psicológicas validadas para población hispanohablante y que conforman las baterías de la Weschler y Luria inicial. Los análisis HJ-biplot realizados muestran que las FE se desarrollan en relación con la edad y el grado escolar de los niños, no obstante, también se observaron diferencias asociadas a las condiciones socioeconómicas y tipo de colegio al que asisten los niños.

Comparison of two color-difference formulas using the Bland-Altman approach based on natural tooth color space.

STATEMENT OF PROBLEM: Several formulas to measure color differences have been proposed to improve the correlation between color measurements and visual perception. Despite the progress obtained, equating between formulas is complex, rendering the exchange of information in scientific papers difficult. PURPOSE: The purpose of this study was to determine the relationship between the results provided by classic CIELab (ΔEab∗) and the CIEDE2000 (ΔE00) formulas in the natural tooth color space using the Bland and Altman limits of agreement, to use this relationship to establish the equivalences between the tooth color thresholds of acceptability and perceptibility of both formulas, and to evaluate whether the relationship between ΔEab∗ and ΔE00 is modified depending on the axis on which the changes occur. MATERIAL AND METHODS: The L∗, a∗, and b∗ means coordinates in the 26 shade tabs of the Toothguide 3D Master were used, and color differences were calculated in 325 pairs of shade tabs using the CIELab (ΔE∗ab) and CIEDE2000 (ΔE00) color difference formulas. The results obtained with these formulas were compared, and the limits of agreement after a logarithmic transformation of the data were obtained. RESULTS: The linear relationship between both formulas was ΔE00 =0.66ΔE∗ab. The results obtained with the CIELab formula were between 1.15 (95% confidence interval 1.11 to 1.18) and 2.09 (95% confidence interval 2.03 to 2.15) times higher than those obtained with the CIEDE2000 formula. CONCLUSIONS: In the natural tooth color space, the scale factor between CIEDE2000 and CIELab values changes from 0.46 to 0.90, such that providing an accurate scale factor between both values is difficult. Furthermore, the ΔE00/ΔE∗ab ratio increases with the increase in ΔL∗ and the decrease in Δb∗. The pairs for which the ratio is highest are those in which the difference in color is mainly due to changes in lightness, whereas the pairs for which the ratio is the smallest are those in which the difference in color is mainly due to changes on the blue-yellow axis.

Evolución de la calidad seminal en una población no industrializada procedente de Salamanca durante los últimos treinta años / Trends in semen quality in a non-industrialized population from the Salamanca

Fundamento y Objetivo: Analizar la tendencia secular de la calidad seminal a lo largo de los últimos 30 años (1978-2007) en la población de Salamanca. Hasta el momento, no existe información sobre dicha tendencia en áreas no industrializadas del sur de Europa. Sujetos y Método:Analizamos la calidad seminal en 612 varones sanos y normospérmicos derivados a nuestra unidad para evaluación andrológica. El estudio ha sido realizado en un solo Centro, y el mismo técnico, altamente experimentado, ha realizado todos los análisis en el mismo laboratorio. Resultados: La edad de los sujetos en el momento de consulta ha aumentado, mientras que el intervalo de relaciones sexuales no protegidas sin fertilidad antes de consulta ha disminuido con el tiempo. El volumen seminal y la concentración espermática disminuyen, mientras que la motilidad espermática aumenta a lo largo de este período. La densidad de espermatozoides con motilidad progresiva por eyaculado muestra una clara tendencia al descenso. Conclusiones: Nuestros resultados demuestran un descenso de la calidad seminal a lo largo de los últimos 30 años en el área de Salamanca, sugiriendo que factores no relacionados con la industrialización pueden estar implicados en el decremento de la calidad seminal (AU)

Background and objective: The objective was to analyze the secular trend in semen quality over the past 30 years (1978-2007) in a population-based study in Salamanca, Western Spain. Information about this issue in non-industrialized areas of Southern Europe is lacking. Subjects and Methods: We analyzed semen quality in 612 consecutive healthy normospermic subjects derived to our unit for andrologic evaluation. The study was performed at a single Centre and a single highly experienced technician made all analyses at the same laboratory. Results: The age of the subjects at diagnosis increased, while the time interval of childless relationships before consultation decreased over time. Semen volume and sperm counts decreased while sperm motility increased over this period. Motile density per ejaculate showed a clearly decreasing trend. Conclusions: Our results demonstrate a decrease in semen quality over the last 30 years in the area of Salamanca in western Spain, suggesting that non-industrial-related factors may be involved in decreasing semen quality (AU)

[Trends in semen quality in a non-industrialized population from the Salamanca area, Spain, during the last 30 years]. / Evolución de la calidad seminal en una población no industrializada procedente de Salamanca durante los últimos treinta años.

BACKGROUND AND OBJECTIVE: The objective was to analyze the secular trend in semen quality over the past 30 years (1978-2007) in a population-based study in Salamanca, Western Spain. Information about this issue in non-industrialized areas of Southern Europe is lacking. SUBJECTS AND METHODS: We analyzed semen quality in 612 consecutive healthy normospermic subjects derived to our unit for andrologic evaluation. The study was performed at a single Centre and a single highly experienced technician made all analyses at the same laboratory. RESULTS: The age of the subjects at diagnosis increased, while the time interval of childless relationships before consultation decreased over time. Semen volume and sperm counts decreased while sperm motility increased over this period. Motile density per ejaculate showed a clearly decreasing trend. CONCLUSIONS: Our results demonstrate a decrease in semen quality over the last 30 years in the area of Salamanca in western Spain, suggesting that non-industrial-related factors may be involved in decreasing semen quality.

Analysis of thyroglobulin gene polymorphisms in patients with autoimmune thyroiditis.

The autoimmune thyroid disease is a complex disorder caused by a combination of genetic susceptibility and environmental factors, which are believed to initiate the autoimmune response to thyroid antigens. Identification of the susceptibility genes has found that unique and diverse genetic factors are in association with Graves' disease and autoimmune thyroiditis. The thyroglobulin gene is an identified thyroid-specific gene associated to autoimmune thyroid disease and, principally, with autoimmune thyroiditis. The aim of this work was to test for evidence of allelic association between autoimmune thyroiditis and thyroglobulin polymorphism markers. We studied six polymorphisms distributed throughout all the thyroglobulin gene: four microsatellites (Tgms1, Tgms2, TGrI29 and TGrI30), one insertion/deletion (Indel) polymorphism (IndelTG-IVS18) and one exonic single nucleotide polymorphism (SNP) (c.7589G>A) in 122 patients with autoimmune thyroiditis compared with 100 non-related normal subjects. No differences in allele and genotype distribution were observed between autoimmune thyroiditis cases and controls for Tgms1, Tgms2, TGrI30, IndelTG-IVS18 and c.7589G>A. However, when we analyzed the patients with the TGrI29 microsatellite we found a significant association between the 199-bp allele and AT (33.7% vs. 24.5% in control group) (P = 0.0372). In addition, a higher prevalence of the 201-bp allele has been observed in control subjects (47.5% vs. 38.1% in patients group), although not statistically significant (P = 0.0536). Our work shows the association between the thyroglobulin gene and autoimmune thyroiditis and reinforce that thyroglobulin is a thyroid-specific susceptibility gene for this disease.

Alternativa a la regresión con componentes principles basada en biplot de regresión / An alterntive to principal components regression based on regression biplot

Se presenta un método alternativo de estimación que permite aproximar el biplot de una matriz de datos a través del ajuste de modelos bilineales, en cuyo caso los denominamos Biplot de Regresión. Su ajuste resulta similar a la Regresión con Componentes Principales, cuando las variables se tratan en el análisis en forma simétrica, su distribución es normal y se introduce convenientemente una métrica en el espacio de las mismas. Sin embargo, los Biplots de Regresión tienen la ventaja de permitir ajustes no lineales y representar confiablemente en forma gráfica, las relaciones entre individuos y/o variables. Para su interpretación se analiza la geometría, en la forma clásica y en términos de proyecciones sobre subespacios de mejor ajuste. Finalmente se realiza un análisis comparativo a través de dos aplicaciones prácticas, demostrando su potencialidad para la aplicación en cualquier campo de las ciencias naturales y sociales