Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 164 )

2018 ( 285 )

2017 ( 272 )

2016 ( 391 )

Custom range...

Search Results: 1 - 10 of 216959 matches for " Salvador;Díaz-González "
All listed articles are free for downloading (OA Articles)
Page 1 /216959
Display every page Item
Determinación de residuos de malatión y malaoxón en mango de las variedades Ataulfo y Tommy Atkins producidos en Chahuites, Oaxaca
Fuentes-Matus, Casibe;Vega y León, Salvador;Díaz-González, Gilberto;Noa-Pérez, Mario;Gutiérrez-Tolentino, Rey;
Agrociencia , 2010,
Abstract: the organophosphate pesticide malathion and its metabolite malaoxón cause harmful effects on the health of humans that consume foods contaminated with these molecules. the presence of residues of malathion and malaoxón was studied in mangos (mangifera indica) of the varieties ataulfo and tommy atkins produced in the municipality of chahuites, state of oaxaca, during the harvest period of 2007. the extraction system used ethyl acetate in aqueous matrix, and analytic determination by means of liquid gas chromatography with thermionic specific detector (tsd). the concentration of residues of malathion and malaoxón was determined for each variety through sampling at 1, 30 and 60 d after having applied malathion (520 g i. a. of malathion ha-1), in compliance with the phytosanitary norm (nom-023-fito) for the control of the mexican fruit fly (anastrepha ludens) on days 1 (t1) and 30 (t2), and two applications of malathion for day 60 (t3). control mangos of both varieties were used, taken from orchards free of pesticide application for 10 years. the presence of malathion was detected in 75 % and 95.6 % of the samples (n=12) of the varieties ataulfo and tommy atkins. residues of the metabolite malaoxón were detected in 83.3 % of the samples (n=12) in both varieties. no degradation was observed of either pesticide once it was present in the fruit until day 60 of the study. furthermore, the means of the residues increased in time three of the study (t3) in both varieties, after two applications of malathion.
Variables of Suicidal Behavior in Tenerife Years 2011-2012: Proposals for the Prevention  [PDF]
Sergio Manuel Martínez Aguilar, Milagros De la Rosa Hormiga, Juan Manuel Herrera Hernández, Francisco Rodríguez Pulido, Candelaria de la Merced Díaz-González
Forensic Medicine and Anatomy Research (FMAR) , 2014, DOI: 10.4236/fmar.2014.22007
Abstract: Suicide is treated by society as a taboo subject despite it being the leading cause of unnatural death in Spain. The Tenerife Province is ranked 16th among the 52 Spanish provinces for its suicide rate. From 2007 till 2010, the rate increased from 2007 to 2008, then dropped in 2010. Slight rise occurred in suicide rates in 2010. This rate increased from 2007 to 2008, with a decrease of rate in 2010. Slight rise occurred in suicide rates in 2010. In 2013 the province saw 75 suicides per year. 90% - 98% of suicides are closely related to mental disease with the remaining 10% associated with different poor causes of the subject, according to bibliography. In this retrospective study, it has been found that the highest risk rests with men over 40 years of age in the central and southern part of the island. Among the forms of suicide reported, the most common is hanging followed by jumping from a height. It’s important to understand the reasons behind suicidal behavior from a psychosocial perspective, taking into account “unsafe” indicators and individual profiles. The lethal nature of a suicide attempt also depends on the form of suicide adopted and the possibility of a rescue. Specific protocols to prevent suicide should be promoted and discussed between health and social services.
Risk factors in dropping out of nursing studies  [PDF]
Milagros De la Rosa Hormiga, Candelaria de la Merced Díaz-González, Josefa María Ramal López, Juan Manuel Herrera Hernández
Open Journal of Nursing (OJN) , 2014, DOI: 10.4236/ojn.2014.41002

School failure is a worrying phenomenon of the educational system that affects most sectors of the education regarding parents, teachers and students and covers education at all levels, from basic education levels to higher levels. One of the levels where there is a high incidence of this problem is in university education, where dropout rates at university are between 25% and 50% in the early formative years. Therefore, it is considered that this phenomenon of school failure and dropout must be addressed and treated from all support systems and services that merge at school, because there are many interests involved not only in the student who fails himself, but also in society in general. The objective of this survey is finding out the effects of anxiety and personal problems in ULPGC nursing students and the consequences that can bring in their academic performance. The results obtained show direct influence of variables such as attendance, studies organization, disappointment feelings, approaching dropout and others, however the hypotheses that were not met differentially, offer us relevant information, for better understanding and making decisions to prevent school failure at university.

Evolution of a Prevention Program in Mental Health in a Municipal Therapeutic Service  [PDF]
Milagros de la Rosa Hormiga, Juan Manuel Herrera Hernández, Candelaria de la Merced Díaz-González, Inmaculada Rodríguez Matos, María Sandra Marrero Morales
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.58108

This study shows the evolution of the demand and assistance in a municipal therapeutic service portfolio in Tenerife. It is a descriptive, qualitative and quantitative study. The sample is made up of 1175 patients assisted in this program in the period of time which ranges from 2005 to 2012. The results show the high demand of this program. Moreover, the results of the intervention coincide with those expected by international and national organisms. Most of the demand is centred on the area of problems called role transitions, followed by those problems grouped in the area of interpersonal conflicts. In the third place, the demand is centred on those problems grouped in the area of interpersonal deficits, and finally on those problems grouped in the category of grieving or mourning problems. It is extremely important to offer this program in the municipal service portfolio as a complementary resource which facilitates the prevention and approach to problems related to mental health in the community because of its high demand, effectiveness and efficacy.

The Identification of Knowledge and Educational Requirements for Secondary School Teachers in the Field of Health Education  [PDF]
David Pérez-Jorge, Milagros De la Rosa Hormiga, Pedro álvarez Pérez, Candelaria de la Merced Díaz-González, María Sandra Marrero Morales
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.66076
Abstract: The present society requires the individuals to have the ability to adapt to changes, as an instrument to achieve the full integration of all of its members. Problems related to health care, both individual and collective, are considered as an essential aspect in the set of social values. Thus, the value attributed to health and wellbeing is a relevant aspect in that set of social values. It can be stated that health education should be a guiding principle in the integral education of the person. In this sense, educational institutions should act as providing basic resources which allow individuals their full development, without forgetting health care and promotion through the development of educational programmes in the field of health. This research shows the design of an instrument for assessing the teachers’ degree of knowledge as regards school health and their attitude and predisposition to learn to solve situations related to health problems in the school context.
Eficiencia relativa de 15 pruebas de discordancia con 33 variantes aplicadas al procesamiento de datos geoquímicos
González-Ramírez, Rosalinda;Díaz-González, Lorena;Verma, Surendra P.;
Revista mexicana de ciencias geológicas , 2009,
Abstract: discordancy tests provide us with a statistical tool that is useful in different areas of science and engineering, including earth sciences. their application represents a rigorous methodology for the detection and elimination of discordant outliers in statistically contaminated normal samples and provides us remaining data without any statistical contamination, which can then be used to estimate the central tendency (mean) and dispersion (standard deviation) parameters. for the empirical evaluation of 15 discordancy tests with 33 variants, an extensive database of 35 reference materials (rm) from four countries (canada, u.s.a., japan, and south africa) having 2220 applicable cases with 41,821 individual geochemical data, was established. nine single-outlier tests with 13 variants and seven multiple-outlier tests with 20 variants (test n4 belongs to both types) along with the new, most precise and accurate critical values, were employed for this evaluation. two statistical parameters quantified the efficiency of discordancy tests: (1) relative efficiency criterion (rec) known from previous work; and (2) relative outlier criterion (roc) proposed in this work. additionally, a methodology was used that combines linear regression analysis with fisher f and student t significance tests. among the single-outlier discordancy tests, the greatest efficiency was shown by kurtosis test (n15), followed by grubbs type tests (n1 and n4) and skewness test (n14), whereas, among multiple-outlier tests, the grubbs test n4 in its three variants seemed to be characterized by the greatest efficiency values. the dixon tests, being much more popular than the grubbs tests, in general presented the smallest efficiencies. one important implication of these results would be to prefer n15, n1, n4, and n14 tests for the application of this outlier-based methodology for geochemical data handling. the quantitative interpretation using the combined methodology of linear regressions and significanc
Díaz-González,Carlos; Arrieta,Andrés-Amell; Suárez,José-Luis;
CT&F - Ciencia, Tecnología y Futuro , 2009,
Abstract: the utilization of new renewable energy sources has been of special interest during the past years, seeking to decrease our dependence on fossil fuels and the corresponding environmental impact derived from their use. the combustion properties of a simulated gas composed of 60% methane and 40% carbon dioxide in volume are determined in this paper by means of calculation algorithms developed by the gasure team, comparing them to pure methane properties. furthermore, the effect of these properties on premixed flame characteristic phenomena is demonstrated. these properties were determined by theoretical estimations. the characteristic phenomena (laminar deflagration velocity, flame structure, radiation pattern) are determined experimentally. results show a high effect of carbon dioxide in the combustion properties and characteristic parameters of a biogas premixed flame such as laminar deflagration velocity, flame structure and gas-methane exchangeability problems. the difference regarding flame structure and combustion properties lead to a difference in radiation pattern of the gases studied.
Critical values for 33 discordancy test variants for outliers in normal samples up to sizes 1000, and applications in quality control in Earth Sciences
Verma, Surendra P.;Quiroz-Ruiz, Alfredo;Díaz-González, Lorena;
Revista mexicana de ciencias geológicas , 2008,
Abstract: in two earlier papers (verma and quiroz-ruiz, 2006, rev. mex. dene. geol, 23,133-161, 302-319) precise critical values for normal univariate samples of sizes n up to 100 have been reported. however, for greater n, critical values are available only for a few tests: nl for n up to 147, n4k2 for nuptol 49, n6, n14 and n15 (for the latter three tests, critical values were reported for only n= 200, 500, and 1000). this clearly demonstrates the need for proposing new critical values for n >100 through an adequate statistical methodology. therefore, modifications of our earlier simulation procedure as well as new, precise, and accurate critical values or percentage points (with four to eight decimal places; average standard error of the mean 0.00000003-0.0039) of 15 discordancy tests with 33 test variants, and each with seven significance levels a = 0.30, 0.20, 0.10, 0.05, 0.02, 0.01, and 0.005, for normal samples of sizes n up to 1000, viz., nmin(1)100(5)200(10)500(20)1000, are reported. for the first time in the literature, the standard error of the mean is also reported explicitly and individually for each critical value. similarly, a new methodology involving artificial neural network (ann) was used, for the first time in published literature, to obtain interpolation equations for all 33 discordancy test variants and for each of the seven significance levels. each equation was fitted using 76 simulated data for n from 100 to 1000 for a given test and significance level. extremely small sums of squared residuals (5.5 × 10 -8 -8.4 ×10-5; generally <10-5) in the ann equations fitted for n=100 to 1,000 were obtained. as a result, the applicability of these discordancy tests is now extended up to 1000 observations of a particular parameter in a statistical sample. the new most precise and accurate critical values will result in more reliable applications of these discordancy tests than have been possible so far in various scientific and engineering fields, particularly for
Tres nuevos geotermómetros mejorados de Na/K usando herramientas computacionales y geoquimiométricas: aplicación a la predicción de temperaturas de sistemas geotérmicos
Díaz-González, Lorena;Santoyo, Edgar;Reyes-Reyes, Juan;
Revista mexicana de ciencias geológicas , 2008,
Abstract: three new improved equations of the na/k geothermometerwere developed through computational (artificial neural networks) and statistical tools (based on ordinary linear regression) from the analysis of a more representative world geochemical database (n=212) than hitherto used. the new na/k geothermometers are given by the following equations: these new geothermometric equations were successfully evaluated and compared with measured deep temperature wellbore logs using a different geochemical database (n=112) to avoid the training and regression bias. the obtained results clearly show that the new geothermometers systematically provide better and reliable estimations of the deep equilibrium temperatures (for temperatures over 160 °c) than the equations previously reported in the geothermal literature. details of the theoretical basis of the na/k geothermometer, the computational and geochemometric methodologies used, as well as the validation and comparison results are outlined in this work.
Evaluación estadística de Materiales de Referencia Geoquímica del Centre de Recherches Pétrographiques et Géochimiques (Francia) aplicando un esquema de detección y eliminación de valores desviados
Marroquín-Guerra, Sylvia Gabriela;Velasco-Tapia, Fernando;Díaz-González, Lorena;
Revista mexicana de ciencias geológicas , 2009,
Abstract: the present study shows the results of a statistical evaluation to establish reliable composition values (central tendency and dispersion parameters) for eight geochemical reference materials (grm) available from centre de recherches pétrographiques et géochimiques (crpg; nancy, france): bauxite bx-n, diorite dr-n, sienite dt-n, potash feldspar fk-n, granite gs-n, microgabbro pm-s, serpentine ub-n, and dolerite ws-e. the methodology consisted in the preparation of updated composition databases for each grm and their statistical data processing. a statistical filter was applied in each element database with ni >5, consisting of simple and multiple deviation/spread, grubbs, dixon, and moments of high order variant tests. the objective of this procedure was to detect and to eliminate discordant outlier values in population samples that according to the theory, tend to be normally distributed. concentration values obtained in this evaluation were compared with working values proposed by crpg, which have been generated by applying a central tendency indicator approach (robust method). an anova statistical evaluation (at 99% confidence level) indicated significant variance differences between the literature working values and those generated in this work in 39% (bx-n) to 70% (ub-n) of studied cases. values of %rsd obtained in this work were generally lower in comparison with those reported by crpg. relative standard deviation percentage difference (δ%rsd) varied from 25 to 100%, although in some cases was higher, reaching until ~1400% (sb for bx-n). according to anova evaluation, no significant differences were observed between microgabbro pm-s average values proposed in this work and those suggested in the literature. for the rest of grm, differences in composition were observed from 1.9% (gs-n) to 18.4% (bx-n) of evaluated cases. in general, considering the eight grm, the magnitude of deviation of average value (δx) was <18.6% for 89% of evaluated elements, whereas that
Page 1 /216959
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.