4,374 research outputs found

    An Approach to Selection of Variety and Planting Date in Corn Silage Production

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    The major purpose of this study is to make additional information available to the farm manager to improve the decision-making process relating to corn silage production. This study is primarily concerned with factors that influence planting date and variety selection. With-in the framework of decision theory analysis, a Bayesian approach is employed to calculate the best time to plant and the best variety to plant. The approach is used both with and without the possible occurrence of harmful spring frosts. The seventy growing degree day method is employed as a criterion for planting date selection. The planting dates are matched with four different season length corn varieties to formulate the courses of action available to the farm manager. The states of nature that may confront a grower are the degrees of damage associated with various frost intensities

    Survival and Nesting Ecology of Scaled Quail in the Trans-Pecos, Texas

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    Scaled quail (Callipepla squamata) are one of the most ecologically and economically important wildlife species in the Trans-Pecos, because they are the primary upland game bird in the Chihuahuan Desert. Using radiotelemetry, we evaluated survival (Kaplan–Meier) and nesting success of quail on 3 study sites in the Trans-Pecos, Texas: one (Santiago Mountain Ranch, central Brewster Co.) was supplemented with milo (Sorghum bicolor) year-round, the second (Lado Ranch, south Culberson Co.) never used supplements, and the third (Apache Ranch, central Culberson Co.) was supplemented with quail blocks. We trapped and radiocollared 164 female quail collectively across all study sites, and followed them for 2 years (May–Sep 2012–2013). There were no survival differences between years within study sites (P = 0.985), so we grouped data across years and compared survival between study sites. Apache Ranch had the lowest survival (55%) compared with the Santiago Mountain Ranch (76.3%) and Lado Ranch (75%). We found 47 nests across the reproductive seasons for 2012 and 2013. On average, scaled quail had high nesting success (72.6%), eggs per nest (11.6), and hatchability (91.25%). Nesting occurred from May to September with peak nesting in June and July. Timing and quantity of rain, combined with range conditions seemed to have the greatest effect on nesting performance

    Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins

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    Indexación: Web of ScienceThe evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative effect of local and global environmental selective pressures, genetic drift, and gene flow. We hypothesize that high gene flow among populations of Humboldt and Magellanic penguins limits local adaptation in MHC I and MHC II, and signatures of selection differ between markers, locations, and species. We evaluated the MHC I and II diversity using 454 next-generation sequencing of 100 Humboldt and 75 Magellanic penguins from seven different breeding colonies. Higher genetic diversity was observed in MHC I than MHC II for both species, explained by more than one MHC I loci identified. Large population sizes, high gene flow, and/or similar selection pressures maintain diversity but limit local adaptation in MHC I. A pattern of isolation by distance was observed for MHC II for Humboldt penguin suggesting local adaptation, mainly on the northernmost studied locality. Furthermore, trans species alleles were found due to a recent speciation for the genus or convergent evolution. High MHC I and MHC II gene diversity described is extremely advantageous for the long term survival of the species.http://onlinelibrary.wiley.com/doi/10.1002/ece3.2502/epd

    Il fantasma dell’autore e l’autore del fantasma

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    Increased mRNA expression of cytochrome oxidase in dorsal raphe nucleus of depressive suicide victims

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    Suicidal behavior is a problem with important social repercussions. Some groups of the population show a higher risk of suicide; for example, depression, alcoholism, psychosis or drug abuse frequently precedes suicidal behavior. However, the relationship between metabolic alterations in the brain and premorbid clinical symptoms of suicide remains uncertain. The serotonergic and noradrenergic systems have frequently been, implicated in suicidal behavior and the amount of serotonin in the brain and CSF of suicide victims has been found to be low compared with normal subjects. However, there are contradictory results regarding the role of noradrenergic neurons in the mediation of suicide attempts, possibly reflecting the heterogeneity of conditions that lead to a common outcome. In the present work we focus on the subgroup of suicide victims that share a common diagnosis of major depression. Based on post-mortem studies analyzing mRNA expression by in situ hybridization, serotonergic neurons from the dorsal raphe nucleus (DRN) from depressive suicide victims are seen to over-express cytochrome oxidase mRNA. However, no corresponding changes were found in the expression of tyrosine hydroxylase (TH) mRNA in the noradrenergic neurons of the Locus Coeruleus (LC). These results suggest that, despite of the low levels of serotonin described in suicide victims, the activity of DRN neurons could increase in the suicidally depressed, probably due to the over activation of serotonin re-uptake. No alteration was found in noradrenergic neurons, suggesting that they play no crucial role in the suicidal behavior of depressive patients

    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

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    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

    Tafonomía del titanosaurio Aeolosaurus colhuehuapensis, Cretácico Superior, Patagonia central, Argentina: un ejemplo de preservación en facies fluviales de desbordamiento

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    Aeolosaurus colhuehuapensis es un titanosaurio procedente del lago Colhué Huapi, en el Sur de Chubut, Argentina. Los materiales estudiados incluyen veintiuna vértebras caudales y siete hemapófisis, y se hallaron articulados en facies correspondientes a depósitos de desbordamientos vinculados a sistemas fluviales multicanalizados y de alta sinuosidad presentes en los aquí denominados ?estratos del lago Colhué Huapi? de edad Campaniano-Maastrichtiano. Estos sistemas poseían importantes fluctuaciones estacionales en la paleodescarga y estaban enmarcados en un clima semi-árido. La historia tafonómica fue inferida a partir del análisis de diversas características presentes en los restos y de observaciones sedimentológicas macro y microscópicas. La presencia tenue de estriamiento longitudinal, la escasa exfoliación, el grado de articulación y el arqueamiento dorsal de la serie caudal, sugieren un corto tiempo de exposición subaérea y rápido sepultamiento. La falta de marcas de abrasión en los elementos conservados indica escaso o nulo transporte, por lo que los mismos podrían ser considerados autóctonos. El curvamiento dorsal de la cola muestra un arqueamiento opistótono, también presente en algunos terópodos y saurópodos, pero aun no documentado en el Grupo Chubut. Las condiciones climáticas actuales, con variaciones de extrema humedad y sequía, afectaron marcadamente los elementos fósiles preservados. El presente trabajo constituye el primer caso de estudio tafonómico en detalle de un dinosaurio preservado en facies de planicie de inundación proximal para el Grupo Chubut. Finalmente, el hallazgo de saurópodos en estas facies es relevante, dado que este tipo de subambiente posee una alta tasa de aporte sedimentario y reducido a nulo retrabajo de los restos óseos, favoreciendo la preservación de elementos esqueletales articulados. Esto es de suma importancia para el análisis taxonómico y filogenético del clado de los titanosaurios, donde la mayoría de los taxones están representados por restos desarticulados y aislados. Palabras clave: Tafonomía, Postura opistótona, Titanosauria, Patagonia.Fil: Casal, Gabriel A.. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Allard, Jose Oscar. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Martínez, Rubén D.. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Luna, Marcelo. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Gonzalez Riga, Bernardo Javier. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

    Goats as Valuable Animal Model to Test the Targeted Glutamate Supplementation upon Antral Follicle Number, Ovulation Rate, and LH-Pulsatility

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    The potential effect of intravenous administration of glutamate on the ovarian activity and the LH secretion pattern, considering the anestrous yearling goat as an animal model, were assessed. In late April, yearling goats (n = 20) were randomly assigned to either (1) Glutamate supplemented (GLUT; n = 10, Live Weight (LW) = 29.6 ± 1.02 kg, Body Condition (BCS) = 3.4 ± 0.2 units; i.v. supplemented with 7 mg GLUT kg−1 LW) or (2) Non-supplemented (CONT; n = 10; LW = 29.2 ± 1.07 kg, BCS = 3.5 ± 0.2 units; i.v. saline). The oats were estrus-synchronized; blood sampling (6 h × 15 min) was carried out for LH quantification. Response variables included pulsatility (PULSE), time to first pulse (TTFP), amplitude (AMPL), nadir (NAD), and area under the curve (AUC) of LH. Ovaries were ultra-sonographically scanned to assess ovulation rate (OR), number of antral follicles (AF), and total ovarian activity (TOA = OR + AF). LH-PULSE was quantified with the Munro algorithm; significant treatment x time interactions were evaluated across time. The variables LW and BCS did not differ (p > 0.05) between the experimental groups. Nevertheless, OR (1.77 vs. 0.87 ± 0.20 units), TOA (4.11 vs. 1.87 ± 0.47 units) and LH-PULSE (5.0 vs. 2.2 pulses 6 h-1) favored (p < 0.05) to the GLUT group. Our results reveal that targeted glutamate supplementation, the main central nervous system neurotransmitter, arose as an interesting strategy to enhance the hypothalamic–hypophyseal–ovarian response considering the anestrous-yearling goat as an animal model, with thought-provoking while promising translational applications
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