118 research outputs found

    ECOLOGICAL INTERACTION OF PANTOPHTHALMUS ROSENI (ENDERLEIN) (DIPTERA: PANTOPHTHALMIDAE) AND THE RED OAK QUERCUS GERMANA SACHLTDL. ET CHAM. (FAGACEAE) IN A MEXICAN CLOUD FOREST

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    The interaction of the wood driller (Pantophthalmus roseni) and the red oak (Quercus germana) in the cloud forests of the Biosphere Reserve El Cielo at Gómez Farías, Tamaulipas, Mexico was studied. Forty mature individuals of Quercus germana were selected for comparison (20 healthy trees, 20 with severe damage, i.e. ³ 15 wood perforations caused by P. roseni). Healthy and damaged trees were measured for levels of herbivory, percentage of foliar nitrogen, total phenols concentration and acorn production. Herbivory was significantly greater (P< 0.05) in healthy than in damaged oaks. The healthy group had 1.5 times more leaf herbivory than the damaged group. Foliar nitrogen content in Q. germana (5.3%) showed significant variations in relation to the seasons (rainy season = 5.2% and dry season = 5.1%) and between damage groups, as well as in the interaction of season and group. The damaged trees group had 1.2 and 1.5 times more phenols concentration than the healthy group during the rainy season and dry season, respectively. Acorn production was significant greater (P< 0.05) for the damaged group than the healthy group. The importance of these results in understanding and managing this insect as a forest pest, as well as, the effects of herbivory in the cloud forests are discussed.La interacción del barreno del encino (Pantophthalmus roseni) y el encino rojo (Quercus germana) fue estudiada en el bosque mesófilo de montaña de la Reserva de la Biosfera El Cielo, Tamaulipas, México. Se seleccionaron cuarenta individuos maduros de Q. germana para comparación (20 árboles sanos y 20 árboles con daño severo, > 15 perforaciones en el fuste causadas por P. roseni). En árboles sanos y dañados fueron medidos los niveles de herbivoría, el porcentaje de nitrógeno foliar, la concentración total de fenoles y la producción de bellotas. La herbivoría fue significativamente mayor (P< 0.05) en los encinos sanos que en los dañados. El grupo de encinos sanos tuvo 1.5 veces más herbivoría foliar que el grupo de los dañados. El contenido de nitrógeno foliar en Q. germana (5.3%) mostró variaciones significativas en relación a las estaciones (estación lluviosa = 5.2% y estación seca = 5.1%) y entre grupos de daño, como también en la interacción de estación y grupo. El grupo de árboles dañados tuvo 1.2 y 1.5 veces más concentración de fenoles que el grupo de los sanos durante la estación lluviosa y la estación seca, respectivamente. La producción de bellotas fue significativamente más grande (P< 0.05) para el grupo de árboles dañados que para el grupo de los sanos. La importancia de estos resultados en la comprensión y el manejo de este insecto como una plaga forestal, así como los efectos de la herbivoría en el bosque mesófilo de montaña son discutidos

    Determinación de la eficiencia de campo para el sistema de máquinas de alza y transporte en el ingenio Pantaleón utilizando diagramas cíclicos en la zafra azucarera 2010 – 2011

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    Presenta aplicación de la metodología y el enfoque de los diagramas cíclicos en el análisis de sistema de máquinas Alza y transporte de la caña de azúcar en el ingenio Pantaleón para determinar su eficiencia en paralelo

    Registro de Herpetogramma bipunctalis (Lepidoptera: Pyralidae: Crambidae) sobre la invasora Alternanthera philoxeroides (Amaranthaceae) en Tamaulipas, México

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    ResumenSe registra por primera vez en México a Herpetogramma bipunctalis (Fabricius) como agente defoliador de la maleza acuática Alternanthera philoxeroides (Mart.) Griseb. Los ejemplares se recolectaron en la margen mexicana del río Bravo, dentro del municipio de Matamoros, Tamaulipas. Se presentan datos sobre el desarrollo del insecto hasta su etapa adulta. Herpetogramma bipunctalis representa un potencial de aprovechamiento para el control biológico de ésta y otras malezas invasoras.AbstractHerpetogramma bipunctalis (Fabricius) is reported for the first time in Mexico as a defoliator agent of aquatic weed Alternanthera philoxeroides (Mart.) Griseb. The specimens were collected in the Mexican margin of the Río Grande in the municipality of Matamoros, Tamaulipas. Data on insect development until adulthood are presented. H. bipunctalis represents a potential use for biological control of this and other invasive weeds

    Análisis del concepto de termodinámica y su aplicación en el efecto MPEMBA

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    En este artículo se trabajó en el concepto de la termodinámica en general, su definición, principios básicos, así como las leyes establecidas como lo son: la ley cero de termodinámica y su aplicación en alimentos, la primera ley de termodinámica, la segunda ley y su aplicación en el efecto MPEMBA ésta supuesta paradoja fue observada y documentada por primera vez en la antigüedad por Aristóteles, quien en una estancia en Turquía observó cómo los habitantes de un pueblo rociaban las estacas de sus empalizadas con agua muy caliente para de esta manera asegurarlas, porque se congelaban con mucha más rapidez. En este efecto se explica el por qué el agua caliente se congela antes que la fría este fenómeno parece atentar contra el sentido común, cabe destacar que funciona solo en determinadas circunstancias. Las causantes más probables son que en el recipiente caliente el líquido circula mejor, el agua más caliente se evapora más. Cuanto más caliente está un líquido, menos gases disueltos le quedan ya que los gases dificultan la congelación. La causa radica en la mayor convección interna y durante más tiempo del vaso más caliente, que favorece la transferencia de calor al congelador

    Fast single image defogging with robust sky detection

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    Haze is a source of unreliability for computer vision applications in outdoor scenarios, and it is usually caused by atmospheric conditions. The Dark Channel Prior (DCP) has shown remarkable results in image defogging with three main limitations: 1) high time-consumption, 2) artifact generation, and 3) sky-region over-saturation. Therefore, current work has focused on improving processing time without losing restoration quality and avoiding image artifacts during image defogging. Hence in this research, a novel methodology based on depth approximations through DCP, local Shannon entropy, and Fast Guided Filter is proposed for reducing artifacts and improving image recovery on sky regions with low computation time. The proposed-method performance is assessed using more than 500 images from three datasets: Hybrid Subjective Testing Set from Realistic Single Image Dehazing (HSTS-RESIDE), the Synthetic Objective Testing Set from RESIDE (SOTS-RESIDE) and the HazeRD. Experimental results demonstrate that the proposed approach has an outstanding performance over state-of-the-art methods in reviewed literature, which is validated qualitatively and quantitatively through Peak Signal-to-Noise Ratio (PSNR), Naturalness Image Quality Evaluator (NIQE) and Structural SIMilarity (SSIM) index on retrieved images, considering different visual ranges, under distinct illumination and contrast conditions. Analyzing images with various resolutions, the method proposed in this work shows the lowest processing time under similar software and hardware conditions.This work was supported in part by the Centro en Investigaciones en Óptica (CIO) and the Consejo Nacional de Ciencia y Tecnología (CONACYT), and in part by the Barcelona Supercomputing Center.Peer ReviewedPostprint (published version

    Ultrasound-based structural health monitoring methodology employing active and passive techniques

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    Currently, structures are examined during manufacturing by means of Non Destructive Tests (NDT), but there is an increasing interest in monitoring its integrity over its whole life cycle by using Structural Health Monitoring (SHM) strategies. The monitoring of aircraft structures is particularly important as they suffer high strain under extreme atmospheric conditions. There is an extensive literature on SHM for aviation available but there are few references on comprehensive methodologies. This article introduces a methodology, a device and the tests used in its validation. The electronic prototype for structural health monitoring applies ultrasound techniques by means of piezoelectric transducers. It is lightweight, has USB 2.0 connectivity and includes data pre-processing algorithms to improve its performance. It can run in pitch-catch and pulse-echo modes employing passive and active techniques. Passive techniques are used to detect impacts or fiber breakage in composite materials. Tests based on active techniques can bring to light several types of damages such as those caused abruptly or those produced progressively by corrosion, delamination or fatigue

    Estudio de la herbivoría de la palma camedor (Chamaedorea Radicalis) mart., en la sierra madre oriental de Tamaulipas, México

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    Rates of insect herbivory (% of leaf area eaten per day) were measured on the radicalis palm (Chamaedorea radicalis Mart.), during three seasons: early and late rainy season and the middle of the dry season at two different sites: temperate and tropical deciduous forest within the state of Tamaulipas, Mexico. In addition, some structural plant parameters (height, cover and diameter stem), physical plant parameters (foliar toughness and water content) and chemical plant parameters (nitrogen and phenols content) were measured, these parameters were correlated with timely (punctual) herbivory measurements. Results from this study show that the early wet season had the most feeding damage (0.17% per day); whereas, the dry season had the least damage (0.09% per day). The rate of herbivory per day during the middle of the wet season was 0.13%. These values are greater than those commonly reported from such habitats. The highest plants (1.1 times more), but with the least covers corresponded to the tropical deciduous forest. Within the tropical semideciduos forest this specie cover 2% of understory, whereas to the temperate forest cover 4%. In addition, nitrogen, phenol, and water content of leaves decreased as the season progressed; whereas, leaf toughness increased. We found leaf toughness during the late rainy season and the dry season to be the most effective repellent to herbivorySe realizaron análisis de la herbivoría (% de área foliar consumida día-1) sobre la palmilla camedor (Chamaedorea radicalis Mart.) durante tres épocas del año: inicio y final de lluvias y época seca en dos diferentes sitios: bosque tropical subcaducifolio y bosque mixto templado en el estado de Tamaulipas, México. Adicionalmente, se realizaron mediciones de algunos parámetros estructurales (altura, cobertura y diámetro del tallo), parámetros físicos de la planta (agua foliar y dureza foliar) y parámetros químicos foliares (nitrógeno foliar y fenoles totales), estos fueron correlacionados con mediciones de herbivoría instantánea. Los resultados muestran mayor consumo foliar al inicio de la época lluviosa (0.17% por día), mientras que en la época seca obtuvo el menor registro (0.09% por día). La tasa de herbivoría diaria durante el final de las lluvias fue de 0.13%. Estos valores son más altos de los comúnmente descritos para esos hábitats. Para el bosque tropical las plantas presentaron la mayor altura (1.1 veces más), pero con menor cobertura (2.1 veces menos). Dentro del bosque tropical esta especie cubre el 2% del sotobosque, mientras que en el bosque templado cubre el 4%. El contenido de nitrógeno, fenoles totales y agua foliar de las hojas decrecen en tanto que la estación del año progresa, en tanto que la dureza foliar se incrementa. Encontramos que la dureza foliar al finalizar las lluvias y durante la época seca, fue la defensa más efectiva para la herbivoría

    Biopolymers from Waste Biomass — Extraction, Modification and Ulterior Uses

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    The residues coming from woodlands and agricultural exploitation constitute the most abundant biomass available on earth. Its importance as a source of renewable energy has grown in addition to the environmental impact. Biomass waste is a lignocellulosic feedstock which contains three main biopolymers: cellulose, hemicellulose and lignin. It could be utilized for the production of a number of value-added products due to their chemical composition, but it is necessary to efficiently recover the valuable biopolymer as intact as possible by different processing techniques.For different applications, the principal objective of pre-treatment is to keep the cellulose intact, meanwhile hemicellulose and lignin are removed. The yields of the fractions depend on the pre-treatment method, which is the most expensive step in biomass conversion. Traditionally, cellulose is obtained by kraft, sulphite and soda treatments. These methods are non-environmentally friendly and generate huge quantities of toxic wastes. Recently developed models considering the environmental laws encourage the sustainable processing of biomass into value-added products. The use of ionic liquids as new solvents for biomass waste and organosolv processes is reviewed, which are used to obtain cellulose. One of the possible applications of cellulose is membrane synthesis, which has been reported for other biomass materials, such as sugarcane bagasse, mango seed and newspaper. In this chapter, some green pre-treatment methods, different sustainable routes for cellulose modification and some of the results obtained on membrane development based on waste biomass are discussed

    SORL1 polymorphisms in Mexican patients with Alzheimer\u27s disease

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    The present study evaluated the risk effect of 12 Single Nucleotide Polymorphisms in the SORL1 gene in the Mexican population using Late-Onset Alzheimer\u27s Disease (LOAD) and control subjects. Considering APOE as the strongest genetic risk factor for LOAD, we conducted interaction analyses between single nucleotide polymorphisms (SNPs) and the APOE genotype. METHODS: Patients were interviewed during their scheduled visits at neurologic and geriatric clinics from different institutions. The LOAD diagnosis included neurological, geriatric, and psychiatric examinations, as well as the medical history and neuroimaging. Polymorphisms in RESULTS: The A/A genotype in rs1784933 might be associated with an increased LOAD risk. Two blocks with high degree linkage disequilibrium (LD) were identified. The first block composed by the genetic variants rs668387, rs689021 and rs641120 showed a positive interaction (mainly the rs689021) with rs1784933 polymorphism. Moreover, we found a significant association between the CONCLUSION: The rs1784933 polymorphism is associated with LOAD in Mexican patients. In addition, the presence o

    Detection of Bartonella bovis DNA in blood samples from a veterinarian in Mexico

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    The genus Bartonella encompasses 38 validated species of Gram-negative, facultative intracellular bacteria that colonize the endothelial cells and erythrocytes of a wide spectrum of mammals. To date, 12 Bartonella species have been recorded infecting humans, causing diseases of long historical characterization, such as cat scratch fever and trench fever, and emerging bartonellosis that mainly affect animal health professionals. For this reason, this study aimed to report a documented case of Bartonella bovis infecting a veterinarian from Mexico by the amplification, sequencing and phylogenetic reconstruction of the citrate synthase (gltA) and the RNA polymerase beta-subunit (rpoB) genes, and to report the natural course of this infection. To our knowledge, this work is the first to report the transmission of B. bovis via needlestick transmission to animal health workers in Latin America
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