2,112 research outputs found

    Editorial

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    Editorial of number 3

    Editorial

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    Editorial del número 3

    Biodigestión anaerobia de residuos sólidos urbanos. Alternativa energética y fuente de trabajo

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    Este artículo describe una propuesta para el manejo de Residuos Sólidos Urbanos (RSU), alternativa a su disposición en rellenos sanitarios (poco eficiente por su alto grado de contaminación), y a la solución ideal, que es la recuperación del 70 al 90% de cada uno de los compuestos de los RSU, o “reciclaje integral”. Se describe aquí el proceso de digestión de los RSU en biodigestores, los cuales aceleran el proceso natural que sucede en rellenos sanitarios para obtener biogás como combustible, además de estabilizar los RSU restantes para su recuperación posterior. La solución propuesta permite además retener el lixiviado y controlar algunas variables para acelerar la digestión

    Estación Meteorológica para la Conformación de Redes. Proceso de Instalación

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    A finales de 2014 se instala en la Facultad Tecnológica de la Universidad Distrital en Bogotá, Colombia una estación meteorológica para la medición y almacenamiento de valores promedios de variables meteorológicas en la localidad Ciudad Bolívar como radiación solar, precipitación, dirección y velocidad del viento, entre otras. Se utiliza, como hardware, un dispositivo inalámbrico de transmisión, automático y compacto marca PEGASUS.Se enfatiza en el procedimiento para la escogencia del lugar más conveniente para el montaje de la estación, siguiendo las normas de la OMM (Organización Meteorológica Mundial), recomendaciones del IDEAM (Instituto de Hidrología, Meteorología y Estudios Ambientales de Colombia) y del fabricante. Se espera que la estación sea parte de una red de estaciones de algunas universidades de Bogotá pertenecientes a la Red Internacional para la Promoción de la Investigación y Docencia en Energización Rural para el desarrollo Sostenible (Red PRIDERAS), también ser parte de la red del IDEAM.)

    Estación Meteorológica para la Conformación de Redes. Proceso de Instalación

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    A finales de 2014 se instala en la Facultad Tecnológica de la Universidad Distrital en Bogotá, Colombia una estación meteorológica para la medición y almacenamiento de valores promedios de variables meteorológicas en la localidad Ciudad Bolívar como radiación solar, precipitación, dirección y velocidad del viento, entre otras. Se utiliza, como hardware, un dispositivo inalámbrico de transmisión, automático y compacto marca PEGASUS.Se enfatiza en el procedimiento para la escogencia del lugar más conveniente para el montaje de la estación, siguiendo las normas de la OMM (Organización Meteorológica Mundial), recomendaciones del IDEAM (Instituto de Hidrología, Meteorología y Estudios Ambientales de Colombia) y del fabricante. Se espera que la estación sea parte de una red de estaciones de algunas universidades de Bogotá pertenecientes a la Red Internacional para la Promoción de la Investigación y Docencia en Energización Rural para el desarrollo Sostenible (Red PRIDERAS), también ser parte de la red del IDEAM.)

    In situ degradability of soyabean meal treated with Acacia saligna and Atriplex halimus extracts in sheep

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    The effects of Acacia saligna (AC) and Atriplex halimus (AT) extracts were evaluated on ruminal soyabean meal (SBM) degradability using the nylon bag technique. Samples of SBM were treated with 0, 4, or 8 g of AC or AT extracts per 100 g SBM. Bags were incubated in two cannulated sheep for 2, 4, 6, 8, 12, 24, and 48 h. The chemical constituents (CCs) of extracts was determined using GC-MS. Rate and potential degradability of dry matter (DM) were decreased (P=0.015) to a greater extent than N degradability (P=0.145) with AC and AT doses. DM and N degradation were decreased (P<0.05) by 15% and 29%; 24% and 47% with AC, and 21% and 29%; 23% and 37% with AT at 4% and 8% for DM and N, respectively. The data suggest the possibility of using these extracts as feed additives to reduce ruminal degradability of SBM in ruminant diets

    In Vitro Gas, Methane, and Carbon Dioxide Productions of High Fibrous Diet Incubated With Fecal Inocula From Horses in Response to the Supplementation With Different Live Yeast Additives

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    Yeast supplementation of horse diets can influence nutrient digestibility and microbiota dynamics in the horse hindgut. In some in vitro [6] and in vivo [4] studies, yeast addition to the diets improved digestion of low-quality forages. It has been shown that yeast supplementation can alter the microbial environment by increasing the total number of hindgut microorganisms [7]. As a result, feed digestion in the hindgut can be enhanced, especially that of the fiber fraction, most likely due to increased numbers of cellulolytic bacteria in the hindgut [8]. In contrast, other studies have reported no effect of yeast addition to equine diets on nutrient digestibility in vitro [7] or in vivo [9].In a randomized block design experiment, the effect of fecal inocula from horses supplemented with live yeast (Saccharomyces cerevisiae) in diets containing 50% oat straw on in vitro total gas (gas production [GP]), methane (CH4), and carbon dioxide (CO2) productions as indicators of hindgut activity was assessed. Three commercial products of S. cerevisiae were tested (1) Biocell F53 (YST53), (2) Procreatin 7 (YST07), and (3) Biosaf SC47 (YST047). For the incubations, each product was added at 0 (control without yeast addition), 2, or 4 mg/g dry matter (DM). Fecal inocula for incubations with each treatment was obtained from Quarter Horse mares fed the same yeast additives for 15 days, resulting in four different fecal inocula (FI53, FI07, FI47, and FI00). The fecal content mixed with the culture media were used to inoculate three identical runs of incubation in bottles containing 1-g DM of substrate (a mixture of concentrate and oat straw [1:1 DM]). The GP, CH4, and CO2 productions were measured at 2, 4, 6, 8, 10, 12, 24, and 48 hours postincubation. Addition of additives YST53 and YST07 at 2 mg/g DM resulted in higher asymptotic GP (linear effect, P ¼.021) and GP during the first 12 hours of incubation (linear effect, P <.05) compared with control without yeast addition, with the highest value being for the dose 2 mg/g DM with the fecal inoculum FI53. The additive YST47 at all doses with fecal inoculum FI47 had lower GP (linear effect, P < .05) at different incubation hours compared with control. The additive YST53 increased GP, CH4, and fermentation kinetics at the dose 2 mg/g DM with decreasing CH4 production by 78% at 4 mg/g DM at 24 hours of incubation. Addition of YST53 at 2 and 4 mg/g DM with fecal inoculum FI53 enhanced fermentation kinetics (P < .05) compared with control and other additives at different doses. It can be concluded that the yeast additive Biocell F53 was the most effective at doses of 2 and 4 mg/g DM compared with other Saccharomyces strains to attain a more favorable hindgut fermentation to digest fibrous roughages by horses

    In vitro ruminal fermentation kinetics and energy utilization of three Mexican tree fodder species during the rainy and dry period

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    A factorial experimental design (3×2×3) was used to evaluate the effect of season of harvest and type of ruminal inoculums on in vitro ruminal fermentation kinetics and energy utilization of three browse tree foliages (Lysiloma acapulcencis, Quercus laeta and Pithecellobium dulce). Browse species were harvested during the dry season (DS) and rainy season (RS) and incubated with three different ruminal inoculums: cow, goats previously adapted (AG) or not adapted (UG) to browse species fed in their daily diet. Chemical composition, total condensed tannin (TCT), free-condensed tannin (free-CT), protein-bound condensed tannin (PCT), fiber-bound condensed tannin (FCT) as well as in vitro assaying of ruminal gas production kinetics was determined, while the short chain fatty acids (SCFA) and metabolizable energy (ME) were estimated. Crude protein (CP) was considerably higher (season×browse; P<0.001) during RS. P. dulce had the lowest neutral detergent fiber (NDFom) and acid detergent fiber (ADFom) in both seasons, while L. acapulcencis had the highest values and Q. laeta values were intermediate, with an overall increase in fiber fractions in DS browse foliages (season×browse; P<0.001). TCT content in tree species revealed differences (P<0.01). FCT and PCT were lower in Q. laeta and P. dulce during the RS than in DS, lower (P<0.01) Free-CT fractions were observed in L. acapulcencis and Q. Laeta than in P. dulce, during both seasons. in vitro gas production parameters was increased (P<0.05) in DS than in RS in browses with low and medium tannins contents (i.e., P. dulce and Q. laeta); consequently, browses energy utilization (i.e., SCFA and ME) and organic matter degradability (OMD) as well as fermentation efficiency (i.e., partition factor; PF) were improved (P<0.05). Generally, P. dulce had the highest (P<0.001) ruminal fermentation parameters and energy utilization values (more in DS than RS), while lowest values were founded in L. acapulcencis. Ruminal fluid ofADandUGhad higher (P<0.001) browse ruminal fermentation kinetics, efficiency and energy utilization than cow’s rumen fluid. The browse fermentation and energy utilization was improved in DS versus in RS and the browse fermentation and utilization were highest (P<0.05) in AG ruminal fluid than the others. Our results suggested a better nutritive value of P. dulce and Q. laeta with low and medium tannins contents and high CP concentration in cows and goats during the DS. Goats previously fed browse species in diets had a better ability to degrade and ferment the browse species than other animals

    Nutraceutic effect of free condensed tannins of lysiloma acapulcensis (kunth) benth on parasite infection and performance of pelibuey sheep

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    Abstract Forty-five Pelibuey sheep were experimentally infested with nematodes to evaluate the effect of three free condensed tannin (FCT) levels of Lysiloma acapulcensis on fecal egg counts (FECs), packed cell volumes (PCV), ocular mucosa colors (OMC), average daily gain (ADG), and adult nematode count. Five treatments were used: 12.5, 25.0, and 37.5 mg of FCT kg−1 of body weight (BW); sterile water (control); and ivermectine (0.22 mg kg−1 of BW) as chemical group. The data were processed through repeated measure- ment analysis. Even though the three FCT doses decreased (P < 0.05) the FEC, the highest reduction was obtained with 37.5 mg kg−1 of BW. No differences were observed in PCV and OMC. Higher ADG (P < 0.05) was observed with 37.5 mg kg−1 of BW of FCT. The count of adult nematodes (females and males) in the higher dose of FCT was similar to chemical treatment. Dose of 37.5 mg kg−1 of BW decreased the parasite infection and improved the lamb performance. Therefore, this dose could be used as a nutraceutic product in sheep production.This work was undertaken with funds from the Universidad Autónoma del Estado de México (Project UAEM 1026/2014RIFC). Our gratitude also goes to the Mexican National Council for Science and Technology (CONACYT) for the grant received by Cesar García Hernández

    Identification of viral infections in the prostate and evaluation of their association with cancer

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    <p>Abstract</p> <p>Background</p> <p>Several viruses with known oncogenic potential infect prostate tissue, among these are the polyomaviruses BKV, JCV, and SV40; human papillomaviruses (HPVs), and human cytomegalovirus (HCMV) infections. Recently, the Xenotropic Murine Leukemia Virus-related gammaretrovirus (XMRV) was identified in prostate tissue with a high prevalence observed in prostate cancer (PC) patients homozygous for the glutamine variant of the RNASEL protein (462Q/Q). Association studies with the R462Q allele and non-XMRV viruses have not been reported. We assessed associations between prostate cancer, prostate viral infections, and the RNASEL 462Q allele in Mexican cancer patients and controls.</p> <p>Methods</p> <p>130 subjects (55 prostate cancer cases and 75 controls) were enrolled in the study. DNA and RNA isolated from prostate tissues were screened for the presence of viral genomes. Genotyping of the RNASEL R462Q variant was performed by Taqman method.</p> <p>Results</p> <p>R/R, R/Q, and Q/Q frequencies for R462Q were 0.62, 0.38, and 0.0 for PC cases and 0.69, 0.24, and 0.07 for controls, respectively. HPV sequences were detected in 11 (20.0%) cases and 4 (5.3%) controls. XMRV and HCMV infections were detected in one and six control samples, respectively. The risk of PC was significantly increased (Odds Ratio = 3.98; 95% CI: 1.17-13.56, p = 0.027) by infection of the prostatic tissue with HPV. BKV, JCV, and SV40 sequences were not detected in any of the tissue samples examined.</p> <p>Conclusions</p> <p>We report a positive association between PC and HPV infection. The 462Q/Q RNASEL genotype was not represented in our PC cases; thus, its interaction with prostate viral infections and cancer could not be evaluated.</p
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