Dinámica de perturbación-recuperación de las zonas forestales en el Parque Nacional Nevado de Toluca

Pese a la plena conciencia sobre los graves problemas de deforestación que sufren los bosques mexicanos, existen muy pocos estudios detallados que permitan identificar, de forma precisa, las dinámicas de perturbación-recuperación a que estos ecosistemas se encuentran sujetos. El presente trabajo, plantea una metodología detallada para analizar los procesos de cambio en la cobertura vegetal y uso del suelo, del Parque Nacional Nevado de Toluca (PNNT) para el periodo 1972-2000 aplicando métodos de cartografía automatizada y procesos de reclasificación. Se estimó una tasa de deforestación de 8,4% para dicho periodo, con un cambio en más de 2,000 ha y una pérdida anual de superficie forestal cercana a 156 ha. Se estimaron además las probabilidades de transición, a fin de conocer la disminución y/o incremento en la densidad de las zonas forestales, y en consecuencia, la dinámica de perturbación-recuperación forestal. Finalmente, fue posible caracterizar los procesos de deforestación de una de las áreas naturales protegidas más emblemáticas de México

PROCESOS DE DEFORESTACIÓN Y REDUCCIÓN DE DENSIDAD DEL ARBOLADO DEL PARQUE NACIONAL NEVADO DE TOLUCA

Históricamente las áreas naturales de alta montaña en México han sufrido de presión a sus recursos naturales provocados por diversos factores como la extracción de recursos maderables y las plagas y enfermedades. Los intentos de zonificación resultan muy generalistas y se hace imposible hacer una evaluación de las transiciones menores de 10 años, debido a que los procesos necesarios para su evaluación suponen una elevada inversión en tiempo para tener un producto detallado y funcional. Para el Parque Nacional Nevado de Toluca se elaboró un mapa de ocupación del suelo para 2009 con una imagen SPOT basado en la categorización Cetenal de uso de suelo y vegetación escala 1:50 000 para 1972 y se contrastó con la más reciente actualización para el año 2000 como referencia. Se realizó una sobreposición de los mapas de ocupación del suelo para los años 2000 y 2009 para hacer la interpretación interactiva por sectores de las transiciones en el periodo de estudio. Así se obtuvieron las áreas en donde se ha verificado deterioro en terrenos forestales. Las áreas con mayor dinámica negativa son los bosques de pino, por efectos de deforestación y de pérdida de densidad del arbolado. Se calculó una tasa general de 35 ha año-1, contra solo 3 ha año-1 de bosques recuperados. Se concluye que el área natural protegida está sujeta a intensos procesos de tala selectiva de manera ilegal o por saneamiento

On the early stages of wind-wave generation under accelerated wind conditions

International audienceWhen wind starts to blow, a momentum transfer initiates through the air-water interface generating ocean wave. This transfer is usually characterized in terms of the drag coefficient, CD, but its dependency with wind speed still presents remarkable scatter in the experimental studies. Besides, Babanin and Makin (2008) found that gustiness were responsible to the most distant outliers in drag coefficient values. Also, several studies showed the influence of the sea state and wave age in the roughness and drag coefficient behavior (Smith et al. 1992; Donelan et al. 1993; Drennan 2003). Most of the past studies of wind-waves generation considered uniform and stationary wind speeds. However, in open field it is common to have conditions of wind blowing with a certain acceleration before the constant wind condition is reached. In order to study the early stages of the generation of waves under accelerated wind conditions, a total of five experiments with a characteristic wind speed acceleration were conducted in a large wind-wave facility at the Institut Pytheas (Marseille-France). Momentum fluxes were estimated from hot wire anemometry and, the free surface displacement was measured along the channel tank by resistance and capacitance wire probes. High resolution wind speed and water elevation measurements were acquired at a high resolution rate. During experiments the wind speed was increased with a constant acceleration over time, reaching a constant maximum intensity of 13 m/s. It was observed that during accelerated wind conditions, drag coefficient values depends on the degree of development of the flow regime in the air section and on wave field generation and evolution. The acceleration of wind speed has a direct influence on water surface roughness and water wave evolution in time and in space

High Temperature Electrochemical Engineering and Clean Energy Systems

Global power demand is projected to more than double by 2050 and meeting this increased power demand will require maintaining or increasing power output from all existing energy sources while adding a large amount of new capacity. The power sources that have the greatest opportunity to fulfill this demand gap over this time period are clean energy sources including solar and nuclear power. One of the areas of expertise that SRNL has been applying to help with a variety of clean energy technologies is in high temperature electrochemistry. Savannah River National Laboratory (SRNL) in collaboration with industrial and university partners has used high temperature electrochemical engineering to make improvements in solar power, nuclear fuel reprocessing, and fusion energy technologies. This article describes how high temperature electrochemistry has been applied at SRNL to mitigate corrosion in high temperature CSP systems, develop novel methods of nuclear fuel processing, and recover tritium in fusion energy technologies

Effect of microencapsulated phenolic compound extracts of Maclura tinctoria (L.) Steud on growth performance and humoral immunity markers of white leg shrimp (Litopenaeus vannamei, Boone, 1931) juveniles

Aim of study: The effect of microencapsulated phenolic compound extracts of Maclura tinctoria (MTBE) on growth performance and humoral immunity markers of the white leg shrimp Litopenaeus vannamei juveniles (0.5 ± 0.2 g initial weight) was studied.Area of study: M. tinctoria was collected from Hampolol, Campeche, and Arroyo del Agua, Culiacan, Sinaloa, Mexico.Material and methods: Three MTBE inclusions (0.5, 1, and 2.5 g MTBE/kg, Purina®) were compared with a control commercial feed (Purina®) during 30 days. Nine phenolic acids, nine flavonols, four dihydro-flavonoids, four flavones, and seven unidentified phenolic compounds were determined fin the MTBE using a Perkin Elmer® HPLC chromatograph and diode array-detection.Main results: The mean concentrations of total phenolic compounds, total flavonoid compounds, and condensed tannins were 198.05 ± 5.59 mg gallic acid equivalent (GAE) g-1 dw, 78.57 ± 1.80 quercetin equivalent g-1, and 28.32 ± 0.33 mg epicatechin equivalent g-1, respectively. The ferric reducing antioxidant power and the total antioxidant capacity, respectively, averaged 28.32 mg GAE mL-1 and 10.9 mg ascorbic acid equivalent mL-1. Survival, weight gain, and specific growth rate of L. vannamei were similar among the experimental diets. The dietary inclusion of MTBE at 0.5 g/kg of food showed significant higher (p < 0.05) plasma hemocyte lysate protein (1.35 ± 0.055 µg mL-1), prophenoloxidase (0.47 ± 0.15, Abs. 492 nm), and superoxide anion (O2.-) activity (0.21 ± 0.07, Abs. 630 nm).Research highlights: The supplementation of MTBE at 0.5 g/kg of food could be considered as a potential alternative additive for L. vannamei diet in the juvenile production, since it improved the response of the humoral immunity markers at post larval life stages, when cultivated shrimp are more susceptible to be infected by pathogens

TcVac1 vaccine delivery by intradermal electroporation enhances vaccine induced immune protection against Trypanosoma cruzi infection in mice

Trabajo de investigación doctoral de Wael Hegazy Hassan Moustafa bajo la dirección de Juan Carlos Vázquez ChagoyánThe efforts for the development and testing of vaccines against Trypanosoma cruzi infection have increased during the past years. We have designed a TcVac series of vaccines composed of T. cruzi derived, GPI-anchored membrane antigens. The TcVac vaccines have been shown to elicit humoral and cellular mediated immune responses and provide significant (but not complete) control of experimental infection in mice and dogs. Herein, we aimed to test two immunization protocols for the delivery of DNA-prime/ DNA-boost vaccine (TcVac1) composed of TcG2 and TcG4 antigens in a BALB/c mouse model. Mice were immunized with TcVac1 through intradermal/electroporation (IDE) or intramuscular (IM) routes, challenged with T. cruzi, and evaluated during acute phase of infection. The humoral immune response was evaluated through the assessment of anti-TcG2 and anti-TcG4 IgG subtypes by using an ELISA. Cellular immune response was assessed through a lymphocyte proliferation assay. Finally, clinical and morphopathological aspects were evaluated for all experimental animals. Our results demonstrated that when comparing TcVac1 IDE delivery vs IM delivery, the former induced significantly higher level of antigen-specific antibody response (IgG2a + IgG2b > IgG1) and lymphocyte proliferation, which expanded in response to challenge infection. Histological evaluation after challenge infection showed infiltration of inflammatory cells (macrophages and lymphocytes) in the heart and skeletal tissue of all infected mice. However, the largest increase in inflammatory infiltrate was observed in TcVac1_IDE/Tc mice when compared with TcVac1_IM/Tc or non-vaccinated/infected mice. The extent of tissue inflammatory infiltrate was directly associated with the control of tissue amastigote nests in vaccinated/ infected (vs. non-vaccinated/infected) mice. Our results suggest that IDE delivery improves the protective efficacy of TcVac1 vaccine against T. cruzi infection in mice when compared with IM delivery of the vaccine.Universidad Autónoma de Estado de México (proyecto No. 3326/2012C), Consejo Nacional de Ciencia y Tecnología (Proyecto No. 156701) . Beca CONACyT a M.Sc. Wael Hegazy Hassan Moustafa (Beca numero No. 518232/291117)

Overexpression of CYB5R3 and NQO1, Two NAD\u3csup\u3e+\u3c/sup\u3e-Producing Enzymes, Mimics Aspects of Caloric Restriction

Calorie restriction (CR) is one of the most robust means to improve health and survival in model organisms. CR imposes a metabolic program that leads to increased stress resistance and delayed onset of chronic diseases, including cancer. In rodents, CR induces the upregulation of two NADH‐dehydrogenases, namely NAD(P)H:quinone oxidoreductase 1 (Nqo1) and cytochrome b5 reductase 3 (Cyb5r3), which provide electrons for energy metabolism. It has been proposed that this upregulation may be responsible for some of the beneficial effects of CR, and defects in their activity are linked to aging and several age‐associated diseases. However, it is unclear whether changes in metabolic homeostasis solely through upregulation of these NADH‐dehydrogenases have a positive impact on health and survival. We generated a mouse that overexpresses both metabolic enzymes leading to phenotypes that resemble aspects of CR including a modest increase in lifespan, greater physical performance, a decrease in chronic inflammation, and, importantly, protection against carcinogenesis, one of the main hallmarks of CR. Furthermore, these animals showed an enhancement of metabolic flexibility and a significant upregulation of the NAD+/sirtuin pathway. The results highlight the importance of these NAD+ producers for the promotion of health and extended lifespan

Memoria del segundo simposium sobre historia, sociedad y cultura de México y América Latina

La presente obra reúne 20 ponencias de las 27 que se presentaron en el “Segundo simposium sobre historia, sociedad y cultura de México y América Latina”, realizado el 8 y 9 de noviembre de 2006, en el Centro de Investigación en Ciencias Sociales y Humanidades (CICSyH) de la Universidad Autónoma del Estado de México (UAEM), en Toluca, Estado de México

Analyses of an Expressed Sequence Tag Library from Taenia solium, Cysticerca

A method used to describe expressed genes at a specific stage in an organism is an EST library. In this method mRNA from a specific organism is isolated, transcribed into cDNA and sequenced. The sequence will derive from the 5′-end of the cDNA. The library will not have sequences from all genes, especially if they are expressed in low amounts or not at all in the studied stage. Also the library will mostly not contain full length sequences from genes, but expression patterns can be established. If EST libraries are made from different stages of the same organisms these libraries can be compared and differently expressed genes can be identified. Described here is an analysis of an EST library from the pig cysticerca which is thought to be similar to the stage giving the human neglected disease neurocysticercosis. Novel genes together with putative drug targets are examples of data presented

Surgical treatment for colorectal cancer: Analysis of the influence of an enhanced recovery programme on long-term oncological outcomes-a study protocol for a prospective, multicentre, observational cohort study

Introduction The evidence currently available from enhanced recovery after surgery (ERAS) programmes concerns their benefits in the immediate postoperative period, but there is still very little evidence as to whether their correct implementation benefits patients in the long term. The working hypothesis here is that, due to the lower response to surgical aggression and lower rates of postoperative complications, ERAS protocols can reduce colorectal cancer-related mortality. The main objective of this study is to analyse the impact of an ERAS programme for colorectal cancer on 5-year survival. As secondary objectives, we propose to analyse the weight of each of the predefined items in the oncological results as well as the quality of life. Methods and analysis A multicentre prospective cohort study was conducted in patients older than 18 years of age who are scheduled to undergo surgery for colorectal cancer. The study involved 12 hospitals with an implemented enhanced recovery protocol according to the guidelines published by the Spanish National Health Service. The intervention group includes patients with a minimum implementation level of 70%, and the control group includes those who fail to reach this level. Compliance will be studied using 18 key performance indicators, and the results will be analysed using cancer survival indicators, including overall survival, cancer-specific survival and relapse-free survival. The time to recurrence, perioperative morbidity and mortality, hospital stay and quality of life will also be studied, the latter using the validated EuroQol Five questionnaire. The propensity index method will be used to create comparable treatment and control groups, and a multivariate regression will be used to study each variable. The Kaplan-Meier estimator will be used to estimate survival and the log-rank test to make comparisons. A p value of less than 0.05 (two-tailed) will be considered to be significant. Ethics and dissemination Ethical approval for this study was obtained from the Aragon Ethical Committee (C.P.-C.I. PI20/086) on 4 March 2020. The findings of this study will be submitted to peer-reviewed journals (BMJ Open, JAMA Surgery, Annals of Surgery, British Journal of Surgery). Abstracts will be submitted to relevant national and international meetings.The present research study was awarded a Ministerio de Ciencia e Innovación health research project grant (PI19/00291) from the Carlos III Institute of the Spanish National Health Service as part of the 2019 call for Strategic Action in Health