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Abstract Background Medical education has undergone significant changes over the last decades. Scientific and technological progress alongside contemporary society’s changing requirements have driven demand for highly trained, competent doctors. In response to this need, university faculties of medicine have sought innovative forms of teaching and evaluating the students on their degree courses. The aim of this study was to quantify the characteristics and extent of academic training in teaching methods, of participation in innovative teaching initiatives, and training in simulation and debriefing among the teaching personnel on the degree course in medicine at the University of Granada (Spain). Methods This transversal descriptive study was conducted among a population of 121 educators teaching on the medical degree course at the University of Granada, Spain. All responded to a specially designed CoRe-Content Representation questionnaire. This consisted of various parts: (a) demographic data; (b) teaching experience and qualifications; (c) specific information about training in teaching skills received. The Fisher test was applied whenever the dependent variable had two values (dichotomous) and the Chi-square test when it had more than two values (polytomic). Statistical significance was established with an alpha error of 5%. Results The results showed that 87.60% of the educators had received no training in debriefing. There was a notable gender gap, whereby women held fewer management posts, fewer were engaged in clinical activity, and fewer had undergone training in clinical simulation. Teachers with degrees in medicine had undergone less regulated training than educators with other degree qualifications. Conclusion The main areas of medical training that require improvement (and so present challenges to be met in the years to come) are as follows: a definitive solution to the existing gender gap, general implementation of new educational models and methods (especially learning based on clinical problem-solving and simulation), closing generation gaps, and improved training processes for educators with clinical attachment.

AbstractBacillus subtilis strain LPM1 was previously documented as a plant growth-promoting rhizobacterium under open field conditions. For deeper understanding, the present study was established in a shade house with three different commercial varieties of bell pepper (Prosperity RZ, Valkiria RZ, and Sven RZ) treated prior to transplanting with the B. subtilis LPM1. The trial was performed as three parallel experiments (one per variety) comparing treated (LPM1 inoculated) against untreated (control) plants, with four replicates each. At three different times i.e. 30, 45, and 60 days after inoculation (DAI) biometric parameters, including total dry biomass, foliar area, plant height, stem diameter, and total yield were measured. Physiological parameters such as photosynthetic rate (µmol CO2 m−2 s−1), stomatal conductance (mol H2O m−2 s−1), and transpiration rate (mmol H2O m−2 s−1) were also evaluated. In the vegetative stages, the rhizobacterium B. subtilis LPM1 significantly promoted some plant traits of bell pepper varieties, such as stem diameter and total dry biomass (30, 45, and 60 DAI). However, the fruit number and yield in bell pepper varieties did not show differences between treatments under shade house conditions.

Abstract The main aim was to evaluate changes in urea cycle enzymes in NAFLD patients and in two preclinical animal models mimicking this entity. Seventeen liver specimens from NAFLD patients were included for immunohistochemistry and gene expression analyses. Three-hundred-and-eighty-two biopsy-proven NAFLD patients were genotyped for rs1047891, a functional variant located in carbamoyl phosphate synthetase-1 (CPS1) gene. Two preclinical models were employed to analyse CPS1 by immunohistochemistry, a choline deficient high-fat diet model (CDA-HFD) and a high fat diet LDLr knockout model (LDLr −/−). A significant downregulation in mRNA was observed in CPS1 and ornithine transcarbamylase (OTC1) in simple steatosis and NASH-fibrosis patients versus controls. Further, age, obesity (BMI > 30 kg/m2), diabetes mellitus and ALT were found to be risk factors whereas A-allele from CPS1 was a protective factor from liver fibrosis. CPS1 hepatic expression was diminished in parallel with the increase of fibrosis, and its levels reverted up to normality after changing diet in CDA-HFD mice. In conclusion, liver fibrosis and steatosis were associated with a reduction in both gene and protein expression patterns of mitochondrial urea cycle enzymes. A-allele from a variant on CPS1 may protect from fibrosis development. CPS1 expression is restored in a preclinical model when the main trigger of the liver damage disappears.

During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV-2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3–5 years old and headache in 6–17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age.

Persistence and dropout are two sides of the same coin. Together with personal and social factors, issues associated with the quality of teaching provided by universities determine students’ decision to persist in pursuing their academic degree or, on the contrary, to drop out of university studies. Our working hypothesis is that the impact on improving the quality of teaching by considering pedagogical factors which are currently being researched and experimented with, can improve the overall persistence rate by reducing the dropout rate. Our work consisted of applying an instrument designed to diagnose the risk of dropping out of university studies to a sample of first-year university students at the University of Granada. The instrument was applied at the beginning of the second semester. Of the 642 pupils surveyed, we established a risk group of 20 students. In this preliminary study we intend to make a first approach to the phenomenon of academic failure in Andalusian universities from the prediction and diagnosis of risk groups and the recommendation of preventive measures. Among the measures we propose for prevention, we highlight those that have an impact on pedagogical factors. We propose measures targeting the factors that predict dropout and the implementation of preventive measures.

Resumen: Introducción: la parada cardiorrespiratoria es una de las principales causas de muerte en los países industrializados. La reanimación cardiopulmonar (RCP) por testigos aumenta la supervivencia. En España el nivel de conocimientos al respecto es bajo, suponiendo un exceso de mortalidad. Es urgente formar a la población en general en RCP. Material y métodos: analizamos el impacto de la implementación de un programa de formación en soporte vital para los profesores y los estudiantes de educación secundaria, realizando un estudio observacional, descriptivo y transversal, con una muestra de 649 estudiantes, a los que se aleatorizó en 2 grupos para ser formados por un profesor de educación secundaria previamente instruido en soporte vital o por un sanitario. Posteriormente se analizó la adquisición de competencias y la diferencia según la edad y el sexo de los estudiantes. Resultados: objetivamos una adecuada adquisición de competencias a nivel global, y una diferencia estadísticamente significativa a favor de los estudiantes formados por su profesor en comparación con los que fueron formados por sanitarios. Conclusión: la adquisición de competencias en RCP por parte de los profesores y los estudiantes de educación secundaria presenta un nivel elevado y adecuado como para garantizar la participación de los mismos en los programas formativos, y la aplicabilidad de lo aprendido en situaciones reales. Consideramos que debe sistematizarse la formación en soporte vital a nivel de la educación secundaria obligatoria, por parte de los profesores. Abstract: Introduction: Cardiorespiratory arrest is one of the leading causes of death in industrialized countries. Bystander cardiopulmonary resuscitation (CPR) increases survival. However, there is a low level of general knowledge about this issue in Spain which entails a greater mortality rate in CA cases. It is urgent to train the general population in CPR. Material and methods: The impact of implementing a life support training program for secondary school teachers and students was analyzed. An observational, descriptive, and cross-sectional study was carried out, with a sample of 649 students, who were randomized into two groups to be trained by a secondary school teacher previously instructed in life support or by a health worker. Subsequently, the acquisition of skills and the difference according to the age and sex of the students were analyzed. Results: An adequate acquisition of skills at a global level was observed, and a statistically significant difference in favor of the students trained by their teacher compared to those who were trained by health professionals. Conclusion: Skills acquisition in basic CPR by secondary school students and teachers presents a high and adequate level to guarantee the participation in training programs and the applicability of what is learned in real situations, both for teachers and students. Life support training should be systematized at secondary education level by secondary school teachers.

ABSTRACT Multiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been evaluated in clinical trials. However, trials addressing the immune response in the pediatric population are scarce. The inactivated vaccine CoronaVac has been shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. Here, we report interim safety and immunogenicity results of a phase 3 clinical trial for CoronaVac in healthy children and adolescents in Chile. Participants 3 to 17 years old received two doses of CoronaVac in a 4-week interval until 31 December 2021. Local and systemic adverse reactions were registered for volunteers who received one or two doses of CoronaVac. Whole-blood samples were collected from a subgroup of 148 participants for humoral and cellular immunity analyses. The main adverse reaction reported after the first and second doses was pain at the injection site. Four weeks after the second dose, an increase in neutralizing antibody titer was observed in subjects relative to their baseline visit. Similar results were found for activation of specific CD4+ T cells. Neutralizing antibodies were identified against the Delta and Omicron variants. However, these titers were lower than those for the D614G strain. Importantly, comparable CD4+ T cell responses were detected against these variants of concern. Therefore, CoronaVac is safe and immunogenic in subjects 3 to 17 years old, inducing neutralizing antibody secretion and activating CD4+ T cells against SARS-CoV-2 and its variants. (This study has been registered at ClinicalTrials.gov under no. NCT04992260.) IMPORTANCE This work evaluated the immune response induced by two doses of CoronaVac separated by 4 weeks in healthy children and adolescents in Chile. To date, few studies have described the effects of CoronaVac in the pediatric population. Therefore, it is essential to generate knowledge regarding the protection of vaccines in this population. Along these lines, we reported the anti-S humoral response and cellular immune response to several SARS-CoV-2 proteins that have been published and recently studied. Here, we show that a vaccination schedule consisting of two doses separated by 4 weeks induces the secretion of neutralizing antibodies against SARS-CoV-2. Furthermore, CoronaVac induces the activation of CD4+ T cells upon stimulation with peptides from the proteome of SARS-CoV-2. These results indicate that, even though the neutralizing antibody response induced by vaccination decreases against the Delta and Omicron variants, the cellular response against these variants is comparable to the response against the ancestral strain D614G, even being significantly higher against Omicron.

Background The state of alarm declared in Spain in response to the Coronavirus pandemic (COVID-19) has had far-reaching consequences in all areas of life. At the University of Granada’s (UGR) Faculty of Medicine, online teaching was implemented immediately without any preexisting plan. Second-year undergraduates in medicine, particularly those enrolled in the subject ‘Bases of Internal Medicine,’ would normally undergo clinical skills circuits in face-to-face group settings.Objective To facilitate undergraduates’ acquisition of specific transversal skills by means of an integrated online working system.Design Before the pandemic, teaching/learning methods consisted of 1) face-to-face group work; 2) teletutoring; 3) written work uploaded to the PRADO online platform for marking by the teletutor; and 4) presentation of written work to the group. As a result of the lockdown, presentations in class were suspended and replaced by online presentations. The means adopted by students in online presentations were freely chosen using various communication techniques: linear projection systems (6); acting/simulation (4); dramatization (1); and role-playing (1).Results The number of online clinical skills circuits developed was 12, one for each of the clinical skills circuits established for imparting this subject. A total of 12 presentations were made by the 10 groups, each lasting 15 minutes followed by a 5-minute discussion to settle any questions raised. The presentations were marked jointly by the teaching staff, coordinator, and students.Conclusions The transference of classroom learning to the online environment proved an essential resource for teaching/learning clinical/practical skills during the lockdown, which have never before been imparted at distance.

Resumen: Objetivo: Analizar la curva de olvido en la adquisición de competencias en soporte vital básico con la modalidad formativa de blended learning. Material y métodos: Las habilidades en soporte vital básico fueron evaluadas en 271 alumnos del grado de medicina en la Universidad de Granada. Para ello, se impartió una modalidad docente semipresencial (blended learning) y los discentes fueron evaluados en dos ocasiones, separadas en el tiempo por dos meses. Resultados: En la primera evaluación, todos los participantes realizaron correctamente las maniobras de perfil práctico y presentaron un menor aprendizaje inicial en las de carácter cognitivo y actitudinal. En la reevaluación, las maniobras con mayor olvido fueron la apertura de la vía aérea y la realización de dos ventilaciones. En cambio, las mejor recordadas fueron la petición de ayuda y la alternancia de compresiones y ventilaciones siguiendo una secuencia de 30:2. En el análisis por sexos, las mujeres presentaron mayor curva de olvido en la realización de las maniobras en comparación con los varones, en los que se pudo observar una mejor retención de algunas habilidades respecto a la evaluación inicial. Conclusiones: El sistema de enseñanza basado en blended learning es útil en el proceso de adquisición de las competencias en soporte vital básico. Abstract: Purpose: To analyse the forgetting curve in the acquisition of basic life support competencies by blended learning in third year students of Medicine Degree at the University of Granada. Material and methods: Basic life support skills were evaluated in 271 medical degree students at the University of Granada. For this, a blended learning modality was taught and the students were evaluated on two occasions, separated in time by two months. Results: Practical maneuvers were performed correctly by all students in the first evaluation. But cognitive and attitudinal ones presented less initial learning. The maneuvers with the greatest forgetfulness were opening the airway and performing two ventilations, on revaluation. On the other hand, the best remembered ones were the request for help and the alternation of compressions and ventilations following a sequence of 30: 2. Differences by sex showed that women presented a higher forgetting curve compared to men. Some skills had a better retention by men compared to the initial evaluation. Conclusions: The teaching system based on blended learning is useful in the process of acquiring basic life support competencies.

Abstract Background Long-term effects of COVID-19, also called Long COVID, affect more than 10% of patients. The most severe cases (i.e. those requiring hospitalization) present a higher frequency of sequelae, but detailed information on these effects is still lacking. The objective of this study is to identify and quantify the frequency and outcomes associated with the presence of sequelae or persistent symptomatology (SPS) during the 6 months after discharge for COVID-19. Methods Retrospective observational 6-month follow-up study conducted in four hospitals of Spain. A cohort of all 969 patients who were hospitalized with PCR-confirmed SARS-CoV-2 from March 1 to April 15, 2020, was included. We collected all the SPS during the 6 months after discharge reported by patients during follow-up from primary care records. Cluster analyses were performed to validate the measures. The main outcome measures were return to the Emergency Services, hospital readmission and post-discharge death. Surviving patients’ outcomes were collected through clinical histories and primary care reports. Multiple logistic regression models were applied. Results The 797 (82.2%) patients who survived constituted the sample followed, while the rest died from COVID-19. The mean age was 63.0 years, 53.7% of them were men and 509 (63.9%) reported some sequelae during the first 6 months after discharge. These sequelae were very diverse, but the most frequent were respiratory (42.0%), systemic (36.1%), neurological (20.8%), mental health (12.2%) and infectious (7.9%) SPS, with some differences by sex. Women presented higher frequencies of headache and mental health SPS, among others. A total of 160 (20.1%) patients returned to the Emergency Services, 35 (4.4%) required hospital readmission and 8 (1.0%) died during follow-up. The main factors independently associated with the return to Emergency Services were persistent fever, dermatological SPS, arrythmia or palpitations, thoracic pain and pneumonia. Conclusions COVID-19 cases requiring hospitalization during the first wave of the pandemic developed a significant range of mid- to long-term SPS. A detailed list of symptoms and outcomes is provided in this multicentre study. Identification of possible factors associated with these SPS could be useful to optimize preventive follow-up strategies in primary care for the coming months of the pandemic.

Abstract Dietary fatty acids play a role in the pathogenesis of obesity-associated non-alcoholic fatty liver disease (NAFLD), which is associated with insulin resistance (IR). Fatty acid composition is critical for IR and subsequent NAFLD development. Extra-virgin olive oil (EVOO) is the main source of monounsaturated fatty acids (MUFA) in Mediterranean diets. This study examined whether EVOO-containing high fat diets may prevent diet-induced NAFLD using Ldlr−/−. Leiden mice. In female Ldlr−/−.Leiden mice, the effects of the following high fat diets (HFDs) were examined: a lard-based HFD (HFD-L); an EVOO-based HFD (HFD-EVOO); a phenolic compounds-rich EVOO HFD (HFD-OL). We studied changes in body weight (BW), lipid profile, transaminases, glucose homeostasis, liver pathology and transcriptome. Both EVOO diets reduced body weight (BW) and improved insulin sensitivity. The EVOOs did not improve transaminase values and increased LDL-cholesterol and liver collagen content. EVOOs and HFD-L groups had comparable liver steatosis. The profibrotic effects were substantiated by an up-regulation of gene transcripts related to glutathione metabolism, chemokine signaling and NF-kappa-B activation and down-regulation of genes relevant for fatty acid metabolism. Collectivelly, EVOO intake improved weight gain and insulin sensitivity but not liver inflammation and fibrosis, which was supported by changes in hepatic genes expression.

Las investigaciones orientadas a la agricultura sustentable en años recientes, además de estudiar el efecto de diferentes tratamientos en el desarrollo de las plantas y su rendimiento, involucran también el efecto en la calidad de los productos poscosecha. En el presente estudio se determinó el efecto de la aplicación de tratamientos a base de organismos promotores de crecimiento (Azotobacter chroococcum), solos o combinados con diferentes oligosacarinas de origen péctico (Pectimorf®) o derivados de quitosano (Quitomax®), sobre la calidad poscosecha de frutos de calabacita (Cucurbita pepo L.) var. 'Grey Zucchini'. Se evaluaron características físicas (diámetro polar y ecuatorial, peso, biomasa seca, f irmeza y color), químicas (pH, sólidos solubles totales, acidez titulable y vitamina C), proteínas, actividad enzimática antioxidante (superóxido dismutasa, catalasa y peroxidasas totales), la actividad de polifenol oxidasa y el contenido antioxidante (compuestos fenólicos y capacidad antioxidante). Los resultados indicaron diferencias significativas (P ≤ 0.05) entre el control y los tratamientos en la mayoría de las variables evaluadas, incluyendo color, longitud (aumento de hasta el 15.88%) y ancho (aumento de hasta el 16.25%) del fruto, peso (aumento hasta de 57.31%), biomasa seca (aumento hasta 34.43%), pH (disminución hasta 9.72%), contenido de vitamina C (aumento hasta 162.6%), proteínas (aumento hasta 22.38%) y capacidad antioxidante total (disminución de hasta el 18.72%). Por lo anterior, la aplicación de tratamientos durante el desarrollo de las plantas modifica la calidad y composición de los frutos poscosecha, lo que acentúa la importancia de los tratamientos orgánicos en el desarrollo de las plantas para la obtención de frutos con mejores características organolépticas.

Introduction: Immediate Life Support training is under-represented in medical degrees and little information is available on the medium-term effectiveness of its teaching. Our aim was to analyse the forgetting curve in medical students who received specific training in the three main procedural competencies of Immediate Life Support. Material and methods: A prospective 3-month longitudinal study was conducted on final year medical students at a Spanish university. The items assessed were grouped into three competencies: the performance of cardiopulmonary resuscitation (nine items), instrumentalised airway management with a supraglottic device (five items) and the identification of basic arrhythmias responsible for cardiorespiratory arrest (four items). All measurements were assessed immediately after the training programme and at three months. McNemar's tests were used for statistical analyses. Results: The medical students recruited showed high rates of correct execution of the manoeuvres for all assessed items, both immediately after the programme and at three months. Over 90% of students performed all the manoeuvres correctly at three months, except for appropriate cardiac massage frequency (85.71%). No significant differences were appreciated between the two assessments. Conclusion: The 3-month forgetting curve in Immediate Life Support was non-existent for medical students, suggesting that these programmes are effective in the medium term. This study provides further evidence on a discipline that is undertrained in medical degrees and that is scarcely studied in the current literature. Resumen: Introducción: La formación en Soporte Vital Inmediato está poco representada en las titulaciones de medicina y se dispone de poca información sobre la eficacia a medio plazo de su enseñanza. Nuestro objetivo fue analizar la curva de olvido en los estudiantes de medicina que recibieron formación específica en las tres principales competencias procedimentales del Soporte Vital Inmediato. Material y métodos: Se realizó un estudio longitudinal prospectivo de 3 meses en estudiantes de último curso de medicina de una universidad española. Los ítems evaluados se agruparon en tres competencias: la realización de la reanimación cardiopulmonar (nueve ítems), el manejo instrumentalizado de la vía aérea con dispositivo supraglótico (cinco ítems) y la identificación de las arritmias básicas responsables de la parada cardiorrespiratoria (cuatro ítems). Todas las mediciones se evaluaron inmediatamente después del programa de formación y a los tres meses. Se utilizó el test de McNemar para los análisis estadísticos. Resultados: Los estudiantes de medicina reclutados mostraron altas tasas de ejecución correcta de las maniobras para todos los ítems evaluados, tanto inmediatamente después del programa como a los tres meses. Más del 90% de los estudiantes realizaron correctamente todas las maniobras a los tres meses, excepto la frecuencia de masaje cardíaco adecuada (85,71%). No se apreciaron diferencias significativas entre las dos evaluaciones. Conclusión: La curva de olvido a los tres meses en Soporte Vital Inmediato fue inexistente para los estudiantes de medicina, lo que sugiere que estos programas son eficaces a medio plazo. Este estudio aporta más evidencias sobre una disciplina poco formada en las carreras de medicina y escasamente estudiada en la literatura actual.

Cardiac arrest (CA) is a major public health problem in developed countries. According to the Spanish Cardiopulmonary Resuscitation Council, in Spain there are around thirty thousand deaths a year and about twenty thousand resuscitation attempts, and yet until very recently medical students did not receive formal training in Advanced Life Support (ALS). With the introduction in 2018 of a new subject, we faced the problem of not having established what type of Life Support was appropriate for our students. As a result, the aim of this study is to analyze in a comparative way the degree of acquisition of competences in ALS and Immediate Life Support (ILS) and their temporal evolution by the students of fifth and sixth year (Medicine Degree) of the University of Granada (UGR). To achieve that aim, we obtained the data in an initial evaluation to the medical students who enrolled in the optional subject of Advanced Life Support in the Faculty of Medicine (UGR), during the months of October and November (2019). This evaluation was carried out by external evaluators and was based on the ERC 2015 guidelines. Months later, a reassessment that was carried out during the months of February and March 2020 to the same sample of students gave us the data for the comparison. Data showed that the degree of acquisition of competencies related to the ILS exceeds the level of acquisition of the competences included within the ALS, and that the effect of the Oblivion Curve for the competences included in the ILS is lower than those included in the ALS. We could conclude that the competences that are integrated within the ILS present a higher level of acquisition and a lesser effect on the forgetting curve, so they should become part of the curricular content of the UGR Medical Degree.

El suicidio en población privada de la libertad (PPL) en centros de reclusión de la ciudad de Bogotá, por la comisión de diferentes delitos, trae consigo una serie de preguntas y cuestionamientos que generan inquietud, duda y en ocasiones temor. El objetivo del estudio fue establecer el estado del arte de los estudios realizados y las tendencias halladas sobre conducta suicida en esta población. En esta investigación se encontrarán los principales estudios, investigaciones y documentos tecnicos realizados por funcionarios y académicos, recopilados en trece documentos. Se pudo establecer que son pocos los documentos encontrados (13), pocas las investigaciones y en su mayoría de tipo descriptivo.

Purpose: The aim of this study was to realize whether soil mulching, with different plastic mulch colors, is a suitable practice for the culture of pickling cucumber. Materials and Methods: The crop was cultured or not with black, silver/black, white/black, and aluminum/black plastic films, treatments were evaluated in randomized complete block design, to determine their effect on soil temperature, gas exchange, nutrient concentration, growth, and fruit yield. Results and Conclusions: Black, silver/black, and aluminum/black plastic mulches were higher (p ≤ 0.05) in plant height, leaf area, and shoot dry weight than bare soil at 15 days after sowing, whose results were similar than using white/black film. Maximum, minimum, and mean soil temperatures were higher with all plastic mulches except for aluminum/black, in which the maximum soil temperature was similar to the one in bare soil. There was no difference in net photosynthesis and there was very little difference in nutrient concentration between plants in plastic mulches and plants in bare soil; however, early and total yield showed a higher (p ≤ 0.05) yield in all plastic mulches, and lower with bare soil and white/black plastic mulch. Our results confirm that soil mulching impacts the pickling cucumber yield. We suggest a carefull selection of the color plastic mulch.

Zeolite-clinoptilolite is a hydrated aluminosilicate, which belongs to a group of minerals of volcanic origin and possesses interesting agricultural properties. The aim of this study was to determine the effect of zeolite-clinoptilolite on Solanum lycopersicum Mill. seedling growth, when supplied to substrate in pot culture. An assay was set to test and compare the physical properties of three substrates: peat moss (pm), perlite (per) and zeolite (zeo), and their mixtures (pm:per:zeo) at different proportions: T1 or control = 100:0:0; T2 = 70:30:0; T3 = 70:20:10; T4 = 70:10:20 and T5 = 70:0:30 (v/v). Compared to control plants, substrates containing 30% zeolite increased their water holding capacity (260%), total porosity (8.47%), bulk density (212%) and particle density (230%). Related to control plants grown with 100% peat moss, tomato seedlings cultured in a substrate mixture with 30% zeolite significantly improved shoot length (24.2%), leaf area (64.5%), root length (63.2%), shoot dry weight (62.5%), root dry biomass (208.9%), stem diameter (28.5%) and leaves number (92%), however, the chlorophyll index had no significant effects. The overall outcomes indicated that substrates amendment with zeolite could effectively improve tomato plants growth.

La presente investigación versa sobre la existencia de un dilema, el existente entre trabaja - dores y capitalistas, el cual se presenta mediante dos formas de representación: la primera un modelo basado en la teoría de juegos y la segunda, por medio de la frontera Sraffa-Ricardo, entre el salario y la cuota de ganancia, esto es la determinación de la frontera para tres tipos de circunstancias, la primera donde la cuota de ganancia es nula y el salario es máximo, la segunda cuando el salario es nulo y la cuota de ganancia es máxima y la tercera cuando nos encontramos con los casos intermedios en los cuales, tanto la cuota de ganancia como el salario poseen valores distintos de cero y positivos.

La presente investigación es un breve panorama sobre el ricardianismo como base para la conformación de modelos de corte neoricardiano que contemplan diferencias en su estructura de determinación de costos, en específico, la determinación explícita de los costos de localización y su influencia significativa sobre el proceso de producción. Este recorrido va desde las posturas de Ricardo en el Parlamento en defensa de los capitalistas y en contra de las rentas de los terratenientes, pasando por la formalización del caso haciendo uso de nuevas herramientas como la teoría de juegos, hasta la determinación de un modelo que contempla costos de localización explícitos y su influencia inversa sobre la determinación de la cuota de ganancia.

La Estrategia de fijación de precios (efp) sigue siendo el mecanismo más eficiente que utilizan las empresas para recuperar los costos realizados y asegurarse una determinada rentabilidad, es decir es un medio para capturar valor, siempre y cuando estas empresas hayan sido capaces de generarlo. Dicha estrategia se ha sofisticado a través de los años, buscando siempre hacer la captura de valor en la forma más eficiente posible. El sustancial incremento en el poder de compra del consumidor, la gran variedad de bienes y servicios que se ofrecen, el gran monto de información disponible, la facilidad de la interacción entre clientes y proveedores, la posibilidad de comparar diferentes precios, la forma de colectar información acerca de mercados, consumidores y competidores, hacen necesario analizar los diferentes mecanismos de captura de valor, a través del estudio de la formulación estratégica de fijación de precios.

Con la presente investigación se pretende abordar de manera teórica los condicionantes principales de la localización espacial de las actividades económicas, las cuales pueden agregarse en un único coeficiente, al que llamaremos costos de localización, el cual incluye los efectos de la renta del espacio o territorio, costos de transportación de los productos al mercado y economías de aglomeración (vistas como dotación de infraestructura para servicios urbanos). Aunado a ello, se establece, a partir de los costos de localización, los determinantes que permiten determinar la existencia de una relación inversa entre estos y la cuota de ganancia, manifestando su relevancia en la disminución o aumento de esta última. En este sentido, la localización de las actividades productivas dependerá de que la productividad, según los coeficientes técnicos respectivos, sea lo suficientemente ventajosa como para subsanar dichos costos, en el entendido de que se deseé mantener la misma tasa de ganancia.

La presente investigación corresponde con el establecimiento de las bases en materia de calidad de vida necesarias para la fundamentación de cualesquier política social por encaminar en el Distrito Federal (DF). Es así, como se elabora, en un primer momento, una revisión de la misma desde la década de 1970 hasta el 2000 por delegaciones, para posteriormente presentar un pronóstico para el 2010, en realidad se trata de un pronóstico modesto puesto que sólo está explicitado para un periodo corto de tiempo. Esto tiene como intención observar la tendencia que pudiese tomar una política social cuya orientación se base en lo prospectivo del texto. Es decir, se ofrece exclusivamente una visión positiva que sirva de sustento a las elaboraciones normativas.

In this work, membrane type, filtration pressure, concentration and nature of the crude oil were studied when emulsified crude oil was removed by membrane filtration methods. Interfacial interactions in the crude/water/membrane system were determined by means of interfacial tension and contact angle measurements. Diluted emulsions of Apure (33.4°API) crude oil were filtered over polysulphone and regenerated cellulose membranes and high removal of crude oil was found, with a higher efficiency of the polysulfone membrane. Nevertheless, the regenerated cellulose membrane had a higher permeate flux and better fouling resistance. Filtration done with emulsions made with Apure oil emulsions and with Lagocinco (32.7°API) oil emulsions showed that it is possible to remove 93.6% of Apure crude and 91.9% of Lagocinco crude oil. The permeate flux, fouling and crude removal are function of the interfase interaction between crude and the membrane surface.

Esta investigación aplica técnicas convencionales y no convencionales para el tratamiento de aguas de industrias papeleras nacionales. Las muestras evaluadas pertenecen a diferentes puntos de los sistemas de formación de hoja y recuperación de fibras. El tratamiento convencional consta de procesos de aglomeración utilizando cloruro de polialuminio (PACl). El no convencional consta de micro y ultrafiltración con membranas cerámicas y poliméricas de celulosa regenerada y PVDF (polifluoruro de vinilideno) hidrofilizado. El tratamiento de aguas drenadas de la mesa de formación con membranas cerámicas, reveló la dependencia de velocidad tangencial de filtrado sobre la calidad del permeado, siendo 2.5 m/s la velocidad óptima para remoción de turbidez y DQO del 98.5 y 82.4%, respectivamente. Las aguas pertenecientes a circuitos de recuperación se trataron combinando procesos de aglomeración con PACl y filtración con membranas poliméricas. En general, la combinación de métodos revela un mejoramiento en el flujo de permeado y en remoción de sólidos, cenizas, y particularmente en la disminución de la DQO en 57.31%.Conventional and non-conventional techniques for white water treatment in local paper-making mills were studied. The tested samples were taken from different points from the forming board and fiber recovery systems. The conventional treatment consisted of agglomeration processes using polyaluminum chloride (PACl). The non-conventional treatment consisted on the use of micro- and ultra- filtration techniques based on regenerated cellulose, ceramic and polymeric, hydrophilic PVDF (polyvinylidene fluoride) membranes. Treatment of drained water from the forming board was accomplished with ceramic membranes which were used to correlate tangential velocity and permeate quality.Anoptimum tangential velocity of 2.5m/swas found for optimal turbidity andCODremoval in the range of 98.5 and 82.4%, respectively. Water from the recovery circuits was treated with PACl to produce agglomerates followed by filtration with ceramic membranes. The combined procedure (PACl followed by ultrafiltration), yielded an improved permeate flux, solids and ash removal with a reduction inCODupto 57.31%.

La generación de espumas en procesos industriales representa en algunos casos severos inconvenientes en fenómenos de transferencia de masa y calor. Además, las dificultades asociadas con la aplicación de antiespumantes, hacen necesario investigar métodos alternativos para romper espumas. Este estudio considera el rompimiento mecánico de espumas acuosas, que fluyen por mallas metálicas. Se consideran en este estudio la variación de flujo de gas, tamaño de orificio, separación entre mallas y tiempo de residencia. Se forman espumas estables a partir de soluciones de dodecil sulfato de sodio y goma de xantano. Se encontró que el volumen de líquido drenado se incrementa al aumentar el flujo de gas, hasta un valor límite donde la espuma se refina y no colapsa, dependiendo del separador empleado. Existe dependencia entre las variables estudiadas; se encontró un óptimo de rompimiento a mínima separación entre mallas, con tamaño de orificio entre 1,5 y 2 veces menor al de las burbujas formadas con bajo flujo de gasFoam generation represents in some industrial processes a serious drawback in the operation of many types of equipment that limit mass and heat transfer. Difficulties associated with the use of antifoams, have led to investigate alternative methods of foam breaking. This study considers the aqueous foam breaking by mechanical methods using parallel metallic meshes. In this study, the residence time, the gas flow, the mesh holes size were considered. Stable foams were formed using a sodium dodecil sulphate solution and xanthans gums. It was found that, depending on the separator used, the drained liquid volume increases when the flow of gas is increased, until a limiting value where the foam refines and does not collapse. It was also found that there is an optimum foam breakage when there is a minimum separation of the meshes and the relation between the holes size of the meshes and the bubble size is between 1.5 and 2, when gas flow is low.

Resumen En este trabajo se estudió la des-acidificación del suero lácteo fermentado obtenido a partir de la fabricación del queso Bonsalut, por medio de un electrodializador modelo CH-0 de Asahi Glass Co. Se evaluó un suero dulce que se fermentó en condiciones ambientales de laboratorio, aproximadamente a una temperatura en el rango de 18-24°C. El suero se caracterizó utilizando las técnicas de acidez titulable, pH, conductimetría, grasa por Gerber, proteínas por Kjeldahl, la lactosa por el método fotométrico con ácido pícrico, sodio y potasio por absorción atómica. El seguimiento de la operación de desalado y des-acidificación se hizo por acidez titulable, conductimetría y pH. Los resultados obtenidos indicaron que es posible des-acidificar el suero en un 78% y que se puede desalar en un 90%. Además, se observó que el desalado ocurrió antes que la des-acidificación debido a que los iones que componen las sales, tienen mayor movilidad que los que componen el ácido, el cual es fundamentalmente ácido láctico. Los resultados sugieren, que para separar el ácido láctico de sueros salados, se debe hacer un proceso en dos etapas, primero se debe desalar el suero y luego des-acidificarAbstract In this work, the acid separation from Bonsalut cheese fermented whey, with an Asahi Glass Co electrodializer, model CH-0, was studied. Sweet whey was used and was fermented under laboratory conditions (temperature range 18-24°C). The whey was characterized by titrable acidity, pH, conductimetry, proteins by the Kjedahl method, fats by the Gerber method, lactose by picric acid fotometry and sodium and potassium by atomic absorption. The de-acidification was followed by conductimetry, pH measurements and titrable acidity. The results show that it is possible to separate 78% of the acid and 90% of the salts. They also show that the salts are separated first, because the ions of the salts have a higher mobility than the ions of the acid, which is mostly lactic acid. These results suggest that to separate lactic acid from fermented whey with a high concentration of salt the process should be carried out in two steps, the first to separate the salt and the second to obtain the acid

Existen básicamente dos enfoques acerca de los determinantes del mercado bursátil, uno es el eficientista y el otro es el ineficientista. A partir de los planteamientos de ambos enfoques y de la herramienta econométrica se construye un modelo capaz de predecir el comportamiento del Índice de Precios y Cotizaciones de la Bolsa Mexicana de Valores para el periodo 2006-2008. Este modelo de pronóstico se compara con un modelo tipo ARIMA con efectos ARCH. La superioridad del modelo basado en los fundamentos es evidente en todo el periodo del pronóstico.

En este trabajo se estudia la relación de causalidad existente entre el tipo de cambio spot y el índice de precios y cotizaciones de la Bolsa Mexicana de Valores desde el punto de vista teórico, empírico y econométrico. Para probar la relación de causalidad econométrica entre estas dos variables se utilizan las técnicas de cointegración, causalidad de Granger y el VAR con el método de corrección del error. Finalmente, se encuentra que en la mayoría de los periodos analizados el mercado cambiario sigue el mercado bursátil.

Background and purpose:: Cytidine-5′-diphosphocholine (citicoline or CDP-choline), an intermediate in the biosynthesis of phosphatidylcholine, has shown beneficial effects in a number of CNS injury models including cerebral ischemia. Citicoline is the only neuroprotectant that has proved efficacy in patients with moderate to severe stroke. However, the precise mechanism by which citicoline is neuroprotective is not fully known. The present study was designed to search for mechanisms of citicoline neuroprotective properties using in vivo and in vitro models of brain ischemia. Methods:: Focal brain ischemia was produced in male adult Fischer rats by occluding both the common carotid and middle cerebral arteries. Brain glutamate levels were determined at fixed intervals after occlusion. Animals were then sacrificed, and infarct volume and brain ATP levels were measured. As in vitro model of ischemia, rat cultured cortical neurones or astrocytes, isolated or in co-culture, were exposed to oxygen–glucose deprivation (OGD) either in the absence or in the presence of citicoline (1–100 μM). Viability was studied by measuring LDH release. Glutamate release and uptake, and ATP levels were also determined. Results:: Citicoline (0.5, 1 and 2 g/kg i.p. administered 1 h before the occlusion) produced a reduction of the infarct size measured at striatum (18, 27 and 42% inhibition, respectively, n = 8, P < 0.05 vs. ischemia), effect that correlated with the inhibition caused by citicoline on ischemia-induced increase in glutamate concentrations after the onset of the ischemia. Citicoline also inhibited ischemia-induced decrease in cortical and striatal ATP levels. Incubation of cultured rat cortical neurones with citicoline (10 and 100 μM) prevented OGD-induced LDH and glutamate release and caused a recovery in ATP levels after OGD, confirming our previous results. In addition, citicoline (100 μM) caused an increase in glutamate uptake and in EAAT2 glutamate transporter membrane expression in cultured rat astrocytes. Conclusions:: Our present findings show novel mechanisms for the neuroprotective effects of citicoline, which cooperate to decrease brain glutamate release after ischemia.

Se estudió la influencia de la homogeneización sobre el tamaño y distribución de los glóbulos grasos de la leche, así como, el efecto de dicha distribución sobre el rendimiento y las propiedades organolépticas de los quesos de pasta blanda obtenidos a partir de leche con 2,5, 2,8 y 3,2% de contenido graso. Se elaboraron quesos de pasta blanda con leche pasteurizada sin homogeneizar (LPSH), y leche pasteurizada y homogeneizada a 0,93 MPa/10 min y 1,2 MPa/15 min (LPH). Dichos quesos fueron sometidos a un proceso de maduración de 16 días. El análisis sensorial fue realizado mediante la evaluación por un panel de degustadores. La dureza de la pasta se determinó con el ensayo del índice de penetración. Los quesos LPH, fueron los que presentaron mejores propiedades organolépticas, y los de 3,2% de grasa fueron los de mayor calidad global entre los quesos de leche pasteurizada y homogeneizada. La textura más lisa y el mejor rendimiento la presentaron los quesos LPH. El índice de penetración más alto (22 mm) fue para los quesos LPH. El rendimiento para los quesos LPH fue mayor que el de los quesos LPSH en un porcentaje entre 30 y 40.The influence of homogenization on the milk droplet size, distribution, the soft ripening cheese yield and organoleptic properties were studied. Different fat contents of milk were used: 2.5, 2.8 and 3.2%. Cheeses were made with pasteurized and homogenized milk (HM) and pasteurized non homogenized milk (NHM). The milk was homogenized with a needle valve at 0.93 MPa/10 min and 1.2 MPa/15 min. Cheeses were submitted to a ripening process of 16 days. A panel of tasters made the taste analysis. The hardness was tested with a penetrometer. The HM cheeses had the best organoleptic properties with the 3.2% HM cheese considered to be the best of them all. The best yield was obtained with the HM milk, it was a 30 to 40% better than with the NHM. The softest cheeses were those made with HM as shown by the penetration index (highest index 22 mm).

En las economías modernas, el conocimiento se ha convertido en el factor de generación de valor más crítico que la propia inversión física. Este hecho ha dado lugar a nuevos procesos y nuevos productos, originando lo que hoy llamamos Nueva Economía que esta basada en el conocimiento y la administración de la información. La Nueva Economía trata con formas sutiles: información, derechos de autor, valores, bases de datos, es decir, activos intangibles en general. En la actualidad el mundo de las computadoras, el espectáculo y las telecomunicaciones son industrias más importantes que cualquiera de los antiguos gigantes industriales. En los años cincuenta, el ejemplo a seguir era General Motors, la gran productora de autos; en la Nueva Economía, la pauta ha sido establecida por Microsoft

Plantea la tipología de enfoques conceptuales de la pobreza, así como las críticas formuladas a cada uno de ellos, con el objetivo de establecer una base teórica para el estudio de las políticas públicas implementadas a partir de la última década del siglo XX. Desarrolla con más amplitud el concepto de pobreza centrada en la carencia de capacidades planteada por Amartya Sen, en la medida que sirve de sustento preponderante, para el diseño de políticas; pues la esencia de este enfoque se convierte en el eje rector de la «dotación» de un conjunto de capacidades que pongan a las personas en igualdad de oportunidades, se trata pues, de seguir «invertir» recursos públicos en el desarrollo del potencial económico de las sociedades contemporáneas.

En el presente artículo se estima, comenta y pronostica la evolución de la Brecha del Producto que existe entre el nivel de producto efectivo y el producto potencial o de pleno empleo en México para el periodo 1987-2004. Para ello, en primer instancia, se estima la tasa de desempleo natural; tasa asociada con el nivel de producto de pleno empleo. El parámetro de dicha tasa resulta de la suma de tres tasas de desempleo: el registrado en la economía, el oculto y la fuerza laboral utilizada. La primera de ellas es equivalente con la tasa de desempleo oficial, las otras dos se calculan por medio del método del desempleo oculto. Una vez hecho lo anterior, se estima el producto potencial y con éste, la diferencia o Brecha del Producto entre el PIB efectivo y el PIB de pleno empleo; aunado al pronóstico en el corto plazo 2003-2004.

In this paper the workspace and payload capacity of a new design of reconfigurable Delta-type parallel robot is analysed. The reconfiguration is achieved by adjusting the length of the kinematic chains of a given robot link simultaneously and symmetrically during the operation of the robot. This would produce a dynamic workspace in shape and volume. A numerical analysis of the variation of shape and volume of the workspace and payload capacity of the robot is presented. Based both on the results of this analysis and on practical requirements, a proposal for the design of a reconfiguring mechanism is presented.

Introducción: El control de la vía aérea en el quirófano es una responsabilidad del anestesiólogo, por lo que al finalizar su formación debe haber desarrollado las habilidades necesarias para atender esta exigencia. El control adecuado de la vía aérea para garantizar una correcta ventilación y oxigenación no sólo es indispensable en muchos procedimientos anestésico-quirúrgicos sino también en todas aquellas situaciones en las que la función respiratoria está comprometida. En los últimos años se ha producido una proliferación de nuevos dispositivos y se han mejorado las técnicas antiguas de intubación y ventilación proporcionándonos una gran ayuda en el manejo de la vía aérea difícil. Objetivo: Evaluar el empleo de nuevos instrumentales para la intubación difícil. Desarrollo: Se realizó una revisión bibliográfica sobre los nuevos instrumentos para intubación difícil recién llegados a nuestro hospital como estilete luminoso, guía de Eschmann o gum elastic bougie, combitubo, con el fin de adquirir los elementos teóricos para aplicarlo en la práctica clínica. Conclusiones. De acuerdo a la experiencia con estos instrumentos y la literatura revisada, la primera opción es la utilización del combitubo, la guía de Eschmann o gum elastic bougie en segundo lugar y el estilete luminoso en tercer lugar.

The influence of homogenization on the milk droplet size, distribution, the soft ripening cheese yield and organoleptic properties were studied. Different fat contents of milk were used: 2.5, 2.8 and 3.2%. Cheeses were made with pasteurized and homogenized milk (HM) and pasteurized non homogenized milk (HM). The milk was homogenized with a needle valve at 0.93 MPa/ 10 min and 1.2 MPa / 15 min. Cheeses were submitted to a ripening process of 16 days. A panel of tasters made the taste analysis. The hardness was tested with a penetrometer. The HM cheeses had the best organoleptic properties with the 3.2% HM cheese considered to be the best of them all. The best yield was obtained with the HM milk, it was a 30 to 40% better than with the NHM. The softest cheeses were those made with HM as shown by the penetration index (highest index 22 mm).

In this work, the acid separation from Bonsalut cheese fer mented whey, with an Asahi Glass Co electrodializer, model CH-0, was studied. Sweet whey was used and was fermented under laboratory conditions (temperature range 18-24°C). The whey was characterized by titrable acidity, pH, conductimetry, proteins by the Kjedahl method, fats by the Gerber method, lactose by picric acid fotometry and sodium and potassium by atomic absorption. The de-acidification was followed by conductimetry, pH measurements and titrable acidity. The results show that it is possible to separate 78% of the acid and 90% of the salts. They also show that the salts are separated first, be cause the ions of the salts have a higher mobility than the ions of the acid, which is mostly lactic acid. These results suggest that to separate lactic acid from fermented whey with a high concentration of salt the process should be carried out in two steps, the first to separate the salt and the second to obtain the acid.

In this work, membrane type, filtration pressure, concentration and nature of the crude oil were studied when emulsified crude oil was removed by membrane filtration methods. Interfacial interactions in the crude/water/membrane system were determined by means of interfacial tension and contact angle measurements. Diluted emulsions of Apure (33.4°API) crude oil were filtered over polysulphone and regenerated cellulose membranes and high removal of crude oil was found, with a higher efficiency of the polysulfone membrane. Nevertheless, the regenerated cellulose membrane had a higher permeate flux and better fouling resistance. Filtration done with emulsions made with Apure oil emulsions and with Lagocinco (32.7°API) oil emulsions showed that it is possible to remove 93.6% of Apure crude and 91.9% of Lagocinco crude oil. The permeate flux, fouling and crude removal are function of the interfase interaction between crude and the membrane surface.

La generación de espumas en procesos industriales representa en algunos casos severos inconvenientes en fenómenos de transferencia de masa y calor. Además, las dificultades asociadas con la aplicación de antiespumantes, hacen necesario investigar métodos alternativos para romper espumas. Este estudio considera el rompimiento mecánico de espumas acuosas, que fluyen por mallas metálicas. Se consideran en este estudio la variación de flujo de gas, tamaño de orificio, separación entre mallas y tiempo de residencia. Se forman espumas estables a partir de soluciones de dodecil sulfato de sodio y goma de xantano. Se encontró que el volumen de líquido drenado se incrementa al aumentar el flujo de gas, hasta un valor límite donde la espuma se refina y no colapsa, dependiendo del separador empleado. Existe dependencia entre las variables estudiadas; se encontró un óptimo de rompimiento a mínima separación entre mallas, con tamaño de orificio entre 1,5 y 2 veces menor al de las burbujas formadas con bajo flujo de gas

Esta investigación aplica técnicas convencionales y no convencionales para el tratamiento de aguas de industrias papeleras nacionales. Las muestras evaluadas pertenecen a diferentes puntos de los sistemas de formación de hoja y recuperación de fibras. El tratamiento convencional consta de procesos de aglomeración utilizando cloruro de polialuminio (PACl). El no convencional consta de micro y ultrafiltración con membranas cerámicas y poliméricas de celulosa regenerada y PVDF (polifluoruro de vinilideno) hidrofilizado. El tratamiento de aguas drenadas de la mesa de formación con membranas cerámicas, reveló la dependencia de velocidad tangencial de filtrado sobre la calidad del permeado, siendo 2.5 m/s la velocidad óptima para remoción de turbidez y DQO del 98.5 y 82.4%, respectivamente. Las aguas pertenecientes a circuitos de recuperación se trataron combinando procesos de aglomeración con PACl y filtración con membranas poliméricas. En general, la combinación de métodos revela un mejoramiento en el flujo de permeado y en remoción de sólidos, cenizas, y particularmente en la disminución de la DQO en 57.31%.

Resumen En este trabajo se estudió la des-acidificación del suero lácteo fermentado obtenido a partir de la fabricación del queso Bonsalut, por medio de un electrodializador modelo CH-0 de Asahi Glass Co. Se evaluó un suero dulce que se fermentó en condiciones ambientales de laboratorio, aproximadamente a una temperatura en el rango de 18-24°C. El suero se caracterizó utilizando las técnicas de acidez titulable, pH, conductimetría, grasa por Gerber, proteínas por Kjeldahl, la lactosa por el método fotométrico con ácido pícrico, sodio y potasio por absorción atómica. El seguimiento de la operación de desalado y des-acidificación se hizo por acidez titulable, conductimetría y pH. Los resultados obtenidos indicaron que es posible des-acidificar el suero en un 78% y que se puede desalar en un 90%. Además, se observó que el desalado ocurrió antes que la des-acidificación debido a que los iones que componen las sales, tienen mayor movilidad que los que componen el ácido, el cual es fundamentalmente ácido láctico. Los resultados sugieren, que para separar el ácido láctico de sueros salados, se debe hacer un proceso en dos etapas, primero se debe desalar el suero y luego des-acidificar

Se estudió la influencia de la homogeneización sobre el tamaño y distribución de los glóbulos grasos de la leche, así como, el efecto de dicha distribución sobre el rendimiento y las propiedades organolépticas de los quesos de pasta blanda obtenidos a partir de leche con 2,5, 2,8 y 3,2% de contenido graso. Se elaboraron quesos de pasta blanda con leche pasteurizada sin homogeneizar (LPSH), y leche pasteurizada y homogeneizada a 0,93 MPa/10 min y 1,2 MPa/15 min (LPH). Dichos quesos fueron sometidos a un proceso de maduración de 16 días. El análisis sensorial fue realizado mediante la evaluación por un panel de degustadores. La dureza de la pasta se determinó con el ensayo del índice de penetración. Los quesos LPH, fueron los que presentaron mejores propiedades organolépticas, y los de 3,2% de grasa fueron los de mayor calidad global entre los quesos de leche pasteurizada y homogeneizada. La textura más lisa y el mejor rendimiento la presentaron los quesos LPH. El índice de penetración más alto (22 mm) fue para los quesos LPH. El rendimiento para los quesos LPH fue mayor que el de los quesos LPSH en un porcentaje entre 30 y 40.