Transporte de fósforo en un Ultisol bajo pastura

Broadcast applications of inorganic fertilizer and organic amendments to pastures can contribute significant phosphorus (P) loads to surface waters. An experiment was conducted to quantify edge of field P concentrations in runoff and mass losses from plots in an Ultisol-Oxisol complex amended with two inorganic P levels [44 kg P/ha/yr (44PI) and 131 kg P/ha/yr (131 PI)], and an organic P source (broiler litter) [131 kg P/ha/yr (131 PC-)]. The total amount of P was split in two applications for the organic treatment and in four for the inorganic treatments. Vegetation within plots was mainly naturalized tropical pastures (80% coverage) and the soil slope was between 10 and 12%. Hydrologic discharge, suspended sediments, dissolved P and total P (TP) were quantified over a one-year period to 7 August 2003. Runoff from each field was diverted to a fractionator, where 1 or 10% was collected. Of the 174 precipitation events, 59 resulted in significant runoff, and hydrologic discharge accounted for 22% to 35% of the total rainfall (164.3 cm). Sediment losses ranged from 230 to 818 kg/ha. Cumulative TP mass losses were 3.19, 7.04, and 5.02 kg P/ha, for the 44PI, 131 PI, and 131PO treatments, respectively. These losses corresponded to 7.3, 4.9, and 3.5% of the annual P applied in the treatments 44PI, 131 PI, and 131PO, respectively. Although the magnitude of P losses was relatively low from an agricultural production standpoint, these can impact surface-water quality via nutrient enrichment. The greatest magnitude of TP mass losses occurred when application coincided with frequent intense rainfall events. RESUMEN Las aplicaciones de fertilizantes y enmiendas orgánicas a los suelos pueden contribuir cantidades significativas de fósforo (P) a las aguas superficiales. Se realizó un experimento para cuantificar las concentraciones de P en la escorrentía y las pérdidas en masa de P al borde de predio en un Ultisol enmendado con dos niveles de superfosfato triple como fuente inorgánica de P [44 kg P/ha/año (44 Pl) y 131 kg P/ha/año (131PI)] y una fuente orgánica de P [131 kg P/ha/año (131PO)] aplicado como pollinaza. La aplicación de P se fraccionó en dos para la fuente orgánica y en cuatro para la fuente inorgánica. La vegetación dentro de los predios era principalmente de pasturas tropicales naturalizadas y la pendiente varió entre 10 y 12%. La descarga hidrológica, sedimentos suspendidos, P disuelto y P total se cuantificaron durante un año. La escorrentía de cada parcela se canalizó hacia un fraccionador donde se recolectó el 1% o el 10% de la misma. De los 174 eventos de precipitación, 59 resultaron en escorrentía significativa, y la descarga hidrológica varió entre 22 y 35% de la totalidad (164.3 cm). Las pérdidas de sedimento variaron entre 230 y 818 kg/ha/año. Las pérdidas de P cumulativas fueron 3.19, 7.04, y 5.02 kg P/ha, para los tratamientos 44PI, 131 PI, y 131PO, respectivamente. Desde una perspectiva de producción agrícola, la magnitud de las pérdidas de P fueron bajas, pero estas cantidades pueden afectar las aguas superficiales vía el enriquecimiento nutricional. Las mayores pérdidas de P ocurrieron en periodos de tiempo cuando la aplicación coincidió con eventos de lluvia de relativamente alta intensidad y frecuencia. Las aplicaciones de fertilizantes y enmiendas orgánicas a los suelos pueden contribuir cantidades significativas de fósforo (P) a las aguas superficiales. Se realizó un experimento para cuantificar las concentraciones de P en la escorrentía y las pérdidas en masa de P al borde de predio en un Ultisol enmendado con dos niveles de superfosfato triple como fuente inorgánica de P [44 kg P/ha/año (44 Pl) y 131 kg P/ha/año (131PI)] y una fuente orgánica de P [131 kg P/ha/año (131PO)] aplicado como pollinaza. La aplicación de P se fraccionó en dos para la fuente orgánica y en cuatro para la fuente inorgánica. La vegetación dentro de los predios era principalmente de pasturas tropicales naturalizadas y la pendiente varió entre 10 y 12%. La descarga hidrológica, sedimentos suspendidos, P disuelto y P total se cuantificaron durante un año. La escorrentía de cada parcela se canalizó hacia un fraccionador donde se recolectó el 1% o el 10% de la misma. De los 174 eventos de precipitación, 59 resultaron en escorrentía significativa, y la descarga hidrológica varió entre 22 y 35% de la totalidad (164.3 cm). Las pérdidas de sedimento variaron entre 230 y 818 kg/ha/año. Las pérdidas de P cumulativas fueron 3.19, 7.04, y 5.02 kg P/ha, para los tratamientos 44PI, 131 PI, y 131PO, respectivamente. Desde una perspectiva de producción agrícola, la magnitud de las pérdidas de P fueron bajas, pero estas cantidades pueden afectar las aguas superficiales vía el enriquecimiento nutricional. Las mayores pérdidas de P ocurrieron en periodos de tiempo cuando la aplicación coincidió con eventos de lluvia de relativamente alta intensidad y frecuencia

Convection and cracking stability of spheres in General Relativity

In the present paper we consider convection and cracking instabilities as well as their interplay. We develop a simple criterion to identify equations of state unstable to convection, and explore the influence of buoyancy on cracking (or overturning) for isotropic and anisotropic relativistic spheres. We show that a density profile $\rho(r)$, monotonous, decreasing and concave , i.e. $\rho' < 0$ and $\rho'' < 0$, will be stable against convection, if the radial sound velocity monotonically decreases outward. We also studied the cracking instability scenarios and found that isotropic models can be unstable, when the reaction of the pressure gradient is neglected, i.e. $\delta \mathcal{R}_p = 0$; but if it is considered, the instabilities may vanish and this result is valid, for both isotropic and anisotropic matter distributions.Comment: 16 pages, 5 figure

Production of Transglutaminase by Streptoverticillium ladakanum NRRL-3191 Using Glycerol as Carbon Source

The enzyme transglutaminase (TG) catalyses the formation of covalent bonds between adjacent proteins, thereby improving the gel structure of proteins and has important applications for the food industry. The aims of this work were: (i) to elucidate the effect of agitation speed during the biotechnological production of TG by Streptoverticillium ladakanum NRRL-3191 using glycerol as carbon source; and (ii) to improve TG production by optimising the composition of media based on glycerol, xylose and casein. An agitation speed of 250 rpm and a fermentation time of 72 h resulted in the optimal enzymatic activity (0.628 U/mL) with a productivity of 0.087 U/(mL·h). The composition of media with glycerol, xylose and casein were optimised using an experimental design to improve TG production. The model predicts that the maximum TG activity (0.725 U/mL) can be obtained using glycerol 50.5 g/L and casein 20 g/L without the addition of xylose

Resource Flows Among Three Generations in Guatemala Study (2007–08): Definitions, tracking, data collection, coverage, and attrition

The allocation of resources across generations and the consequences of these allocations represent a research agenda with significant policy implications. At the same time, their empirical investigation imposes immense data requirements, and therefore data collection challenges. In this paper, we describe how we met these challenges, in the Resource Flows Among Three Generations in Guatemala Study, or IGT, carried out in 2006–07. In doing so, we provide a guide for using and interpreting the data collected as part of IGT, as well as an example for others interested in implementing research projects on similar themes elsewhere. Complex research topics, across generations and across a range of possible measures of well-being, led to a relatively complicated sample selection process and survey design, with component modules that were applicable to different “types” of sample members, depending on their generational status and age, and who often lived in different locations. It also led to a wide set of survey domains, ranging from economic, educational, and psychological surveys to clinical medical exams for both the young and the elderly. Survey coverage was above 85% of the targeted sample for most categories of respondents and most modules, and a number of safeguards were in place to ensure high quality data. Biases due to attrition, measured against the original 1970s rounds of survey work upon which IGT built, while present, should not reduce substantially the validity of research findings to come from this rich sample. The extent to which this is true, though, may vary depending on the topic under consideration and the controls included in the analyses.

A qualitative methodology to reduce features in classification problems

In this paper, a preliminary methodology which quantifies the dependence between features in a data set by using the Ameva discretization algo rithm and the advantages of a qualitative model is developed. Thus, different matrices of inter dependence are built providing a grade of depen dence between two features. This methodology is applied to a well-known data set, obtaining promis ing results for the carried out system.Ministerio de Ciencia e Innovacion TIN2009-14378-C02-01 (ARTEMISA

Resultados del tratamiento de la inestabilidad postdisectomia mediante artrodesis posterolateral lumbar

El mecanismo fisiopatológico por el cual, tras una discectomia en columna lumbar, se puede producir inestabilidad en este segmento de la columna, ha sido establecido en múltiples estudios y se encuentra en la bibliografía actual. Sin embargo, hay pocas publicaciones en la literatura que hagan referencia a los resultados de la artrodesis posterolateral lumbar en inestabilidad clínico-radiológica generada tras una discectomia lumbar. El propósito del presente estudio es valorar los resultados obtenidos en mejora de calidad de vida, en pacientes sometidos a artrodesis lumbar con tornillos pediculares en inestabilidad postdisectomía. La población estudiada se trató de 15 pacientes, 10 hombres y 5 mujeres con edades comprendidas entre los 27 y 65 años, la selección de los pacientes además del antecedente de cirugía discal, se basó en la presencia de un cuadro clínico de inestabilidad unido a pruebas radiológicas estáticas, dinámicas y resonancia magnética, y por último la ausencia de problemas de tipo laboral o psicológico, los datos se obtuvieron por entrevista personal y llamada telefónica, utilizando la escala de Oswestry y la escala analógica de Scott. Los resultados obtenidos fueron buenos ya que más del 90% de los pacientes refirieron mejoría en su calidad de vida. Se puede concluir que la artrodesis posterolateral con tornillos pediculares en inestabilidad postdisectomia, es una buena opción quirúrgica, con la cual se puede obtener mejoría del cuadro clínico del paciente.The present study has the aime, the evaluation of results of posterolateral lumbar arthrodesis in patients who had undergone lumbar discal surgery failed because of appearance of instability. Retrospective study in 15 patients with diagnosis instability postdiskectomy made by: clinical, static and dynamic x-ray and MRI, treated with posterolateral lumbar arthrodesis using pedicular screw. Ten males and five female of 27-65 years and average 46, we used the life quality scale Oswestry and Scott scale. The shortest follow up 3 years and longest 6 years. Our results were: time between diskectomy and arthrodesis variated from 1 to 10 years, average 5 years, about: pain intensity, patients need analgesic because pain, help for activities, deambulation, sexual activity all of them improve. We had 3 cases with clinical symptoms, the other one pain free. One case of deep infection of wound where surgical debridement was necessary. Finally Scott¿s scale prior to surgery punctuation was between 1-4. after between 8-10. Excepting 1 case with bad evolution. Conclusion: posterolateral lumbar arthrodesis with pedicular screew can be a good option of treatment in instability postdikectomy

Ramon (\u3ci\u3eBrosimun alicastrum\u3c/i\u3e) Foliage as Supplement for Lactating Dual Purpose Cows

The objective of the present study was to asses the value of ramón (Brosimun alicastrum) foliage as a N-source in replacement of soybean-N in lactating dual purpose cows (Bos indicus x B. taurus). Four lactating cows were used in a latin rectangle design. Ramón was included to replace 0, 33, 66 and 100 % of the soybean-N contained in the supplement. Basal diet was fresh “Taiwán” a cultivar of Elephant grass (Pennisetum purpureum) fed ad libitum. Basal and total dry matter intake, digestibility (total fecal collection), saleable and calf suckled milk yields, and milk composition (fat, protein and lactose) were measured over 15 d periods. Ramon increased the yield of milk constituents (P\u3c 0.05) over those obtained with Taiwán-grass alone, but was inferior (P\u3c 0.05) when soybean was the N source. Total milk yield was reduced 18% in Ramón supplemented cows compared with those supplemented with soybean. Digestibility of dry matter, organic matter and fiber was reduced by Ramón inclusion probably due to its higher fiber and ash content as compared with soybean meal. It was concluded that, although animal performance was not achieved as with soybean meal, supplementing with Ramón is a better strategy than relying on grass alone

Exploring the Emerging Domain of Research on Video Game Live Streaming in Web of Science: State of the Art, Changes and Trends

In recent years, interest in video game live streaming services has increased as a new communication instrument, social network, source of leisure, and entertainment platform for millions of users. The rise in this type of service has been accompanied by an increase in research on these platforms. As an emerging domain of research focused on this novel phenomenon takes shape, it is necessary to delve into its nature and antecedents. The main objective of this research is to provide a comprehensive reference that allows future analyses to be addressed with greater rigor and theoretical depth. In this work, we developed a meta-review of the literature supported by a bibliometric performance and network analysis (BPNA). We used the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) protocol to obtain a representative sample of 111 published documents since 2012 and indexed in the Web of Science. Additionally, we exposed the main research topics developed to date, which allowed us to detect future research challenges and trends. The findings revealed four specializations or subdomains: studies focused on the transmitter or streamer; the receiver or the audience; the channel or platform; and the transmission process. These four specializations add to the accumulated knowledge through the development of six core themes that emerge: motivations, behaviors, monetization of activities, quality of experience, use of social networks and media, and gender issues