1,844 research outputs found

    Condiciones limnológicas en el embalse La Plata en Puerto Rico: 2008 a 2009

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    Water column profiles of important limnological indicators (temperature, pH, dissolved oxygen, reduction potential, nutrients) were collected at the center section of La Plata reservoir in north-central Puerto Rico during 2008 and 2009. Temperatures at the surface ranged from values close to 25° C during the hemisphere winter months (December-February) to approximately 30° C during summer (June-August). Total nitrogen and phosphorus concentrations at the epilimnion (≤ 3-m depth) averaged 1.06 mg/L and 50 µg/L, respectively. Chlorophyll a values averaged 32.4 µg/L, which altogether with its nutrient status, would place this reservoir within the eutrophic-hypereutrophic categories. The annual average volume-weighed dissolved oxygen concentration for the reservoir was 3.02 mg/L, a reflection of the delicate ecological condition of this reservoir. The reservoir remains stratified during a large portion of the year (≥ eight months), inducing prevailing anoxic conditions at the hypolimnion. However, mixing because of incoming flow associated with intense rain events can be common. As a result, the mixing regime of this reservoir is best classified as discontinuous warm polymictic. Runoff associated with intense rainfall is probably the major contributor of hypolimnion dissolved oxygen and nutrient recharge at this reservoir. The distribution of iron (Fe) and manganese (Mn) is strongly influenced by the redox status of the system. Solid phases containing these metals exert a dominant role in the cycling of phosphate in the system. Durante los años 2008 y 2009 se obtuvieron perfiles de la columna de agua de importantes indicadores limnológicos (e.g., temperatura, pH, oxígeno disuelto, potencial de reducción, nutrientes) en la sección central del embalse La Plata, localizado en el norte-central de Puerto Rico. Las temperaturas en la superficie oscilaron entre valores cercanos a 25° C durante los meses de nuestro invierno hemisférico (diciembre a febrero) hasta unos 30° C durante el verano (junio a agosto). Las concentraciones promedio de nitrógeno total y fósforo total en el epilimion (s 3 m de profundidad) fueron 1.06 mg/L y 50 µg/L, respectivamente. La concentración promedio de clorofila a, 32.4 µg/L. en conjunto con su estado nutricional, colocaría a este embalse dentro de las categorías eutrófico-hipereutrófico. La concentración promedio anual de oxígeno disuelto, ponderado por volumen, para el embalse fue de 3.02 mg/L, lo cual refleja la delicada situación ecológica del mismo. El embalse permanece estratificado durante una gran parte del año (a ocho meses), lo cual induce condiciones prevalecientemente anóxicas en el hipolimio. Sin embargo, la mezcla de la columna de agua debido al flujo de entrada asociado con eventos de lluvia intensa puede ser común. Como resultado, el régimen de mezcla de este embalse es mejor clasificado como polimíctico cálido discontinuo. La escorrentía asociada con las intensas lluvias es probablemente el mayor contribuyente de oxígeno disuelto y de recarga de nutrientes en el hipolimio de este embalse. La distribución del hierro (Fe) y manganeso (Mn) está fuertemente influenciada por el estado redox del sistema. Las fases sólidas que contienen estos metales ejercen un papel dominante en el ciclo del fósforo en el sistema

    Evaluación de mejores prácticas de manejo para reducir las pérdidas de nutrientes contaminantes en escorrentía desde suelos enmendados con carnada de pollos parrilleros. I. Adiciones de alum.

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    The effect of alum [AI2(S04)3.14H20] on reducing phosphorus (P) concentrations in runoff water from broiler litter-amended soils was evaluated in various simulated rainfall events. Additions of alum at a 20% (w/wO) rate caused a significant reduction in the "soluble" (CaCI2-extractable) P fraction of the broiler litter matrix. As a result, the soluble P fraction added to the soils through litter application was 43% and 75% less for the 6 t/ha and the 20 t/ha litter treatments with alum than for their untreated (0 alum) counterparts. Total phosphorus (TP) concentrations in runoff for the 6 t/ha and 20 t/ha treatments with no alum were highly enriched, averaging 2.59 mg/L and 6.10 mg/L, respectively. At the highest litter rate (i.e., 20 t/ha) the 20% alum treatment achieved a 52% reduction in the concentration of TP in runoff as compared to that of the no-alum treatment. However, the impact of alum was more notable in reducing dissolved P (DP) losses. Average DP concentration losses for the 20 t/ha broiler litter rate (no alum) was 3.55 mg/L, a value significantly higher than the 1.0 mg/L threshold that has been suggested as a potential limit to control runoff P losses from agricultural fields. At said broiler litter application rate the 10% and 20% alum treatments resulted in reductions of 58% and 70% of the DP concentrations in runoff, respectively. The observed DP concentration losses from the litter treatments containing 20% alum met the 1 mg/L threshold value in practically all instances. Total P losses in runoff were positively correlated with both the amount of CaCI2-extractable P applied to the soils and soil P levels (Olsen) during different stages of the simulation events. The nutritional contents (N, P, and K) of the Bermuda grass samples were reflective of the broiler litter rate. Higher nutritional contents were generally observed with the 20 t/ha treatments as compared to those at the 6 t/ha rate with no alum, even though the effects were statistically significant only for nitrogen. Alum did not seem to exert a significant impact on nutritional content of the Bermuda grass, although a slight decrease (non significant) in both N and P was observed at the 20% alum rate for the 20 t/ha broiler litter rate.El efecto de alum [AI2(S04)3-14H20] en la reducción de las concentraciones de fósforo (P) en las aguas de escorrentía desde los suelos enmendados con residuos de carnadas de pollos parrilleros se evaluó en varios eventos de lluvia simulada. Adiciones de alum a razón de 20% (peso/peso) causaron una reducción significativa en la fracción de P "soluble" (CaCI2-extraíble) presente en la matriz de la carnada de pollos parrilleros. Como resultado, el P soluble añadido al suelo se redujo en un 43% y un 75% para los tratamientos de 6 t/ha y 20 t/ha de residuos de carnada de pollos parrilleros con alum en comparación con sus contrapartes sin alum. Las concentraciones de P total en la escorrentía de los tratamientos 6 t/ha y 20 t/ha de residuos de carnada de pollos parrilleros sin alum resultaron altamente enriquecidas, promediando 2.59 y 6.10 mg/L, respectivamente. En la dosis más alta de residuos de carnada de pollos parrilleros (20 t/ha), el tratamiento de 20% de alum logró una reducción de 52% en la concentración de P total en la escorrentía relativo al tratamiento sin alum. Sin embargo, el efecto más notable de alum fue en la reducción de las pérdidas de P disuelto. Las pérdidas en las concentraciones de P disuelto promedio en el tratamiento de 20 t/ha de residuos de carnada de pollos parrilleros (sin alum) fue de 3.55 mg/L, un valor significativamente mayor que el umbral de 1.0 mg/L que ha sido sugerido como el límite potencial para el control de pérdidas de P por escorrentía de predios agrícolas. En dicha dosis de aplicación los tratamientos de 10% y 20% de alum alcanzaron reducciones de 58% y 70% en las concentraciones de P disuelto en la escorrentía, espectivamente. Las pérdidas en las concentraciones de P disuelto observadas para los tratamientos con 20% de alum cumplieron con el valor umbral de 1.0 mg/L en prácticamente todos los casos, irrespectivamente de la dosis de residuos de carnada de pollos parrilleros evaluada. Las pérdidas de P total en la escorrentía fue correlacionada positivamente tanto con la fracción de P soluble (extraíble con CaCI2) aplicado a los suelos, como con los niveles de P (Olsen) en el suelo durante las diferentes etapas de los eventos de simulación de lluvia. El contenido nutricional (N, P, y K) para muestras de hierba Bermuda reflejó el efecto de las diferentes dosis de residuos de carnada de pollos parrilleros. Se observó un mayor contenido nutricional en los tratamientos de 20 t/ha comparado con los de 6 t/ha. No obstante, los efectos solo fueron estadísticamente significativos para nitrógeno. El alum no parece ejercer un impacto significativo en el contenido nutricional de la yerba Bermuda, aunque se observaron disminuciones leves (no significativas) para N y P en el tratamiento de 20 t/ha de carnada de pollos parrilleros con 20% de alum

    Concentración de nutrientes en la escorrentía de diferentes predios del trópico enmendados con residuos animales bajo condiciones de lluvia natural.

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    Excessive nutrient losses from agricultural soils represent a major source of surface water contamination. In this study we quantified concentrations of total Kjeldahl nitrogen (TKN), dissolved and total phosphorus (DP,TP), and dissolved organic carbon (DOC) in runoff from two animal farm operations of Puerto Rico. The farms, one dairy and one poultry, represented typical conditions (i.e., topography, ecological zone, management system) of these production systems.Two fields were selected for the runoff studies on each farm, and two runoff collectors were installed in each field. Runoff samples were collected under natural rainfall conditions. The average phosphorus concentration in runoff from the poultry fields (5.87 mg TP/L, 4.82 mg DP/L) was significantly greater than that observed from the dairy fields (2.29 mg TP/L, 1.79 mg DP/L). Dissolved phosphorus concentrations represented more than 90% of the total P concentrations on both farms, a situation that may exacerbate the impact on receiving water bodies. Average DP concentrations exceeded 1 mg/L, a limit proposed for the regulation of runoff P concentrations from agricultural lands, in 70% of the runoff events at the dairy farm, and 100% of the events at the poultry farm. The magnitude of the nutrient concentrations on both farms was significantly affected by the time lapse between the manure applications and the first precipitation event. Nutrient concentrations in runoff samples were also significantly affected by rainfall depth.La pérdida excesiva de nutrientes de suelos agrícolas representa una fuente primaria de contaminación de los cuerpos de agua. En este estudio se cuantificaron las concentraciones de nitrógeno total Kjeldahl (NTK), fósforo total y disuelto (PD, PT), y carbón orgánico disuelto (COD) en la escorrentía de dos fincas productoras de animales de Puerto Rico. Las fincas, una vaquería y una avícola, son representativas de las condiciones típicas (i.e., topografía, zona ecológica, sistema de manejo) de estos sistemas de producción. En cada finca se seleccionaron dos predios para estudios de escorrentía y en cada predio se instalaron dos fraccionadores de escorrentía. Se recolectaron muestras de escorrentía generadas por eventos de lluvia natural. La concentración promedio de fósforo en la escorrentía de los predios avícolas (5.87 mg TP/L, 4.82 mg PD/L) fue significativamente mayor que la observada en los predios de la vaquería (2.29 mg PT/L, 1.79 mg PD/L). La concentración de PD representó cerca del 90% de la concentración de PT observada en ambas fincas, situación que puede agravar el impacto en las aguas circundantes. La concentración de PD promedio excedió 1 mg/L, límite propuesto para controlar la escorrentía de fósforo de predios agrícolas, en 70% de los eventos de escorrentía en el caso de la vaquería y en un 100% de los casos en la finca avícola. La magnitud de las concentraciones en ambas fincas se afectó significativamente por el lapso de tiempo transcurrido entre la aplicación de los residuos orgánicos y el primer evento de lluvia. La concentración de nutrientes en la escorrentía también se afectó significativamente con la profundidad de la lámina de lluvia

    For which infants with viral bronchiolitis could it be deemed appropriate to use albuterol, at least on a therapeutic trial basis?

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    Although there is increasing evidence showing that infants with viral bronchiolitis exhibit a high degree of heterogeneity, a core uncertainty shared by many clinicians is with regard to understanding which patients are most likely to benefit from bronchodilators such as albuterol. Based on our review, we concluded that older infants with rhinovirus (RV) bronchiolitis, especially those with a nasopharyngeal microbiome dominated by Haemophilus influenzae; those affected during nonpeak months or during non-respiratory syncytial virus (RSV) predominant months; those with wheezing at presentation; those with clinical characteristics such as atopic dermatitis or a family history of asthma in a first-degree relative; and those infants infected with RSV genotypes ON1 and BA, have the greatest likelihood of benefiting from albuterol. Presently, this patient profile could serve as the basis for rational albuterol administration in patients with viral bronchiolitis, at least on a therapeutic trial basis, and it could also be the starting point for future targeted randomized clinical trials (RCTs) on the use of albuterol among a subset of infants with bronchiolitis

    Injectiveness and Discontinuity of Multiplicative Convex Functions

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    In the present work we study the set of multiplicative convex functions. In particular, we focus on the properties of injectiveness and discontinuity. We will show that a non constant multiplicative convex function is at most 2-injective, and construct multiplicative convex functions which are discontinuous at infinitely many points

    Encephalitozoon cuniculi

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    This is the first confirmed report of Encephalitozoon cuniculi (E. cuniculi) in farm meat rabbits located in Northern Mexico. Eighty young rabbits exhibited clinical signs of this zoonotic emerging disease, like torticollis, ataxia, paresis, circling, and rolling. Samples of brain, kidney, and liver were examined for histology lesions. For the first time the lesions caused by E. cuniculi were graded according to their severity (I, II, and III) and the size of the granulomas (Types A, B, and C). The main cerebral injuries were Grade III, coinciding with the presence of Type C granulomas. The cerebral lesions were located in the cortex, brain stem, and medulla. The renal lesions were also Grade III distributed throughout cortex and renal medulla, with no granuloma formation. The involvement of hypersensitivity Types III and IV is suggested. All of the rabbits were seropositive to E. cuniculi by CIA testing, suggesting that this zoonotic and emerging pathogen is widely distributed among animals intended for human consumption. We believe this work could be used as a guide when examining E. cuniculi and will provide direction to confirm the diagnosis of this pathogen

    Revealing stage-specific expression patterns of long noncoding RNAs along mouse spermatogenesis

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    The discovery of a large number of long noncoding RNAs (lncRNAs), and the finding that they may play key roles in different biological processes, have started to provide a new perspective in the understanding of gene regulation. It has been shown that the testes express the highest amount of lncRNAs among different vertebrate tissues. However, although some studies have addressed the characterization of lncRNAs along spermatogenesis, an exhaustive analysis of the differential expression of lncRNAs at its different stages is still lacking. Here, we present the results for lncRNA transcriptome profiling along mouse spermatogenesis, employing highly pure flow sorted spermatogenic stage-specific cell populations, strand-specific RNAseq, and a combination of up-to-date bioinformatic pipelines for analysis. We found that the vast majority of testicular lncRNA genes are expressed at post-meiotic stages (i.e. spermiogenesis), which are characterized by extensive post-transcriptional regulation. LncRNAs at different spermatogenic stages shared common traits in terms of transcript length, exon number, and biotypes. Most lncRNAs were lincRNAs, followed by a high representation of antisense (AS) lncRNAs. Co-expression analyses showed a high correlation along the different spermatogenic stage transitions between the expression patterns of AS lncRNAs and their overlapping protein-coding genes, raising possible clues about lncRNA-related regulatory mechanisms. Interestingly, we observed the colocalization of an AS lncRNA and its host sense mRNA in the chromatoid body, a round spermatidsspecific organelle that has been proposed as a reservoir of RNA-related regulatory machinery. An additional, intriguing observation is the almost complete lack of detectable expression for Y-linked testicular lncRNAs, despite that a high number of lncRNA genes are annotated for this chromosom

    El índice Ka: un nuevo algoritmo para analizar los componentes de la superficie terrestre en imágenes de satélite

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    El cambio del paisaje de la superficie terrestre, su composición y estructura, ocurrido por causas di- versas, ha estado en la mira de toda la humanidad. Se han desarrollado diversas formas para entender- los y la sensoría remota es lo más reciente y nove- doso para tener un conocimiento rápido de gran- des extensiones. En este estudio se ha desarrollado un nuevo algoritmo para medir estos cambios, así como para identificar valores espectrales de espe- cies de coníferas, utilizando imágenes del satélite Landsat7 ETM+. Los resultados muestran un gran potencial del índice Ka para detectar los diferentes componentes superficiales y su variabilidad debi- do a efectos naturales o antropológicos, etc. The change in the landscape of the terrestrial surface, its composition, and its structure, caused by many factors, has been in the aim of all humanity. Diverse forms have been developed in order to understand them, the sensory remote being the most recent and novel thing in acquiring fast knowledge of large extensions. In this study a new algorithm has been developed to measure these changes, as well as to identify ghastly values of coniferous species using images of the satellite Landsat7 ETM+. The results show a great potential of the Ka index in detecting the different superfi- cial components and its variability due to natural effects or due to man

    Edible films based on black chia (Salvia hispanica l.) seed mucilage containing Rhus microphylla fruit phenolic extract

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    Functional films based on black chia (Salvia hispanica L.) seed mucilage (BCm) containing Rhus microphylla (Rm) fruit phenolic extract were built and characterized. A hydro-alcohol extract (HAE) of Rm was incorporated as the bioactive agent due to its noteworthy phenolic profile, and good antioxidant and antifungal activities. The effects of the BCm concentration (0.2% and 0.4%, w/v), HAE incorporation, and their interaction with glycerol (1.0%, w/v) and calcium chloride (0.05%, w/v) on the films physicochemical properties were evaluated. The filmogenic solutions successfully fitted to the HerschelBulkley model (R2 0.05) changed by the HAE addition, but their surface tension was enhanced (p < 0.05), which could favor their coating ability. The polyanionic nature of the systems (zeta potential-Zp values from 26.9 to 33.3 mV) allowed them to interact with Ca2+ cations, thus forming stable and resistant films. All the films showed low water solubility (15.0% to 22.3%) and high permeability (3.7 to 4.0 × 1010 g m1 s1 Pa1), as well as high biodegradability (moisture content from 66.0% to 80.9%); although the moisture content was reduced (p < 0.05) with HAE addition. The combination of higher BCm ratio and HAE addition (BCm0.4+Rm) led to a more resistant, thick, opaque, and dark film compared with the others obtained. This study reveals the BCm-based films potential, highlighting those with HAE, representing a novel alternative to improve the quality of food products.Financial support from Universidad Autónoma Agraria Antonio Narro (UAAAN) is gratefully acknowledged by the authors. Zlatina Genisheva thanks to Foundation for Science and Technology (FCT) for the financial support (ref. SFRH/BPD/108868/2015) and to the project COMPETE 2020 (POCI-01-0145-FEDER-029145). This study was supported by FCT under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would also like to thank to Pablo Virgen of Biocampo S.A. de C.V. and MSc Fidel Peña-Ramos from UAAAN, for their assistance during this study.info:eu-repo/semantics/publishedVersio
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