Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Descomposición de macrófitas en el arroyo Las Flores (Buenos Aires)

The macrophytes contribute significantly to the autochthonous primary production of the streams of the Buenos Aires province. Their biomass is partly exported, mainly during floods, and partly incorporated to the detritus pathway of the water bodies. The aim of this study is to determine the losses in weight and nitrogen along the process of decomposition of Lemna gibba and Ceratophyllum demersum, two of the dominant species in the Las Flores stream. A total of 40 bags with 4 g (fresh weight) of L. gibba and 10 g of C. demersum were set in two sites of the stream. Periodically, 4 samples of each species were redrawn, and the dry weight and total nitrogen concentration were determined. L. gibba lost 50% of its weight in 4 days, from then on and until the end of the incubation period (50 days) the weight kept approximately constant, fitted to a Hill’s function with a maximum rate of 0.158 day-1. The weight of C. demersum was almost stable until day 44, and at the end of the following 42 days it was observed that it had lost 62% of its initial weight, with a constant rate of k = 0.0203 day-1. In L. gibba essay, nitrogen concentration lowered from 3.4% to 2.4% in the first 48 hours, thus representing a 52% loss of the total nitrogen content of the plant. For C. demersum, nitrogen concentration decayed from 4.1% until 3.2%; by the end of the sampling, the total nitrogen content had reduced to 33.5% of the initial value. The results indicate that, given the quickness of the decomposition and nutrient release, an important part of the production can be incorporated to the material cycles of the stream before the plants are washed downstream during floods.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Caracterización y evaluaciçón de la capacidad de uso de los suelos de la comarca de "El Aljarafe" (Sevilla)

8 páginas, 5 tablas y 7 referencias. Comunicación presentada en las Actas del VII Congreso Nacional de Química (Química Agrícola y Alimentaria/2). Sevilla (España). 12 al 17 de Octubre de 1987. Vol. 1: "El suelo: fertilidad y fertilizantes". "La planta: aspectos bioquímicos y fisiológicos". "Protección vegetal"The soils of "El Aljarafe" region (Seville) are studied. As a result, different soils are found and classified into 19 taxonomic units of "Soil Taxonomy" (1975) System. Also. their land capability to relative, use, their erosion hazard and their ability for irrigation purposes, are evaluted. A soil map finally, to scale 1/50.000, with the results of the evaluation, is added.Peer reviewe

The S11−NS_{11}- N(1535) and −N-N(1650) Resonances in Meson-Baryon Unitarized Coupled Channel Chiral Perturbation Theory

The $s-$wave meson-baryon scattering is analyzed for the strangeness S=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi N$, $\eta N$, $K \Lambda$, $K \Sigma$. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism and low energy constants are fitted to the elastic $\pi N$ phase-shifts and the $\pi^- p \to \eta n$ and $\pi^- p \to K^0 \Lambda$ cross section data. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths of the $S_{11}-$ $N$(1535) and $-N$(1650) resonances, in reasonable agreement with experiment. A good overall description of data, from $\pi N$ threshold up to 2 GeV, is achieved keeping in mind that the two pion production channel has not been included.Comment: 35 pages, LaTeX + 7 ps-figure files. Some minor mistakes have been corrected for and a new appendix discussing the matching to HBChPT has been also adde

S=−1S=-1 Meson-Baryon Unitarized Coupled Channel Chiral Perturbation Theory and the S01−S_{01}- Λ\Lambda(1405) and −Λ- \Lambda(1670) Resonances

The $s-$wave meson-baryon scattering is analyzed for the strangeness $S=-1$ and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been considered: $\pi \Sigma$, $\bar K N$, $\eta \Lambda$ and $K \Xi$. The required input to solve the Bethe-Salpeter equation is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. There appear undetermined low energy constants, as a consequence of the renormalization of the amplitudes, which are obtained from fits to the $\pi\Sigma\to\pi\Sigma$ mass-spectrum, to the elastic $\bar K N \to \bar K N$ and $\bar K N\to \pi \Sigma$ $t$--matrices and to the $K^- p \to \eta \Lambda$ cross section data. The position and residues of the complex poles in the second Riemann Sheet of the scattering amplitude determine masses, widths and branching ratios of the $S_{01}-$ $\Lambda$(1405) and $-\Lambda$(1670) resonances, in reasonable agreement with experiment. A good overall description of data, from $\pi \Sigma$ threshold up to 1.75 GeV, is achieved despite the fact that three-body channels have not been explicitly included.Comment: 23 pages, Latex, 10 Figures. In this revised version a new subsection 3.6 on Heavy Baryon Expansion and new references have been adde

Chiral unitary approach to S-wave meson baryon scattering in the strangeness S=0 sector

We study the S-wave interaction of mesons with baryons in the strangeness S=0 sector in a coupled channel unitary approach. The basic dynamics is drawn from the lowest order meson baryon chiral Lagrangians. Small modifications inspired by models with explicit vector meson exchange in the t-channel are also considered. In addition the pi pi N channel is included and shown to have an important repercussion in the results, particularly in the isospin 3/2 sector.Comment: 23 pages, LaTeX, 21 figure

Chiral dynamics of p-wave in K^- p and coupled states

We perform an evaluation of the p-wave amplitudes of meson-baryon scattering in the strangeness S=-1 sector starting from the lowest order chiral Lagrangians and introducing explicitly the Sigma^* field with couplings to the meson-baryon states obtained using SU(6) symmetry. The N/D method of unitarization is used, equivalent, in practice, to the use of the Bethe-Salpeter equation with a cut-off. The procedure leaves no freedom for the p-waves once the s-waves are fixed and thus one obtains genuine predictions for the p-wave scattering amplitudes, which are in good agreement with experimental results for differential cross sections, as well as for the width and partial decay widths of the Sigma^*(1385).Comment: LaTeX, 18 pages, 6 figure

Software architecture for the measurement of operational risk in financial sector entities

La medición de los riesgos financieros tales como operacional, liquidez y crédito, entre otros, es una de las preocupaciones más frecuentes en el sector financiero; en este sentido, la materialización del riesgo operacional da lugar a enormes pérdidas monetarias derivadas de fallos en las personas, en los procesos y en los procedimientos que inciden en la operación de la entidad. Con el fin de sistematizar la medición del riesgo operacional se ha desarrollado el Sistema de Información Operational Risk Management, el cual facilita la medición del riesgo operacional, a partir de la obtención de la matriz de pérdidas esperadas e inesperadas y la estimación de Valor en Riesgo Operacional (Op-VaR) para los diferentes fallos que se puedan presentar en cada una de las líneas de negocio con las que cuenta la entidad. En este trabajo se muestra cómo el uso de la arquitectura basada en filtros facilita y agiliza cálculos que requieren grandes volúmenes de datos con información financiera. Actualmente el Sistema de Información es utilizado por entidades del sector financiero colombiano quienes a partir de su uso han optimizado tanto sus utilidades como la productividad del talento humano, toda vez que el sistema ha permitido generar planes de contingencia para atender una crisis por riesgo operacionalThe measurement of financial risks, such as operational, liquidity and credit, among others, is one of the most frequent concern in the bank and corporative sector, in this sense, the operational risk materialization causes large losses due to fails on the procedures that affect the functioning of the organization. With the goal of systematize the risk measurement, we has implement the Information System Financial Risk Management which facilitates the measurement of operational risk starting on the expected and unexpected loss matrix and the estimation of Value at Operational Risk (Op-VaR) for different failures that may occur in each of the business lines that the entity has. The paper shows how the use of filters based on easier and faster calculations that require large volumes of data from financial information architecture. Currently the Information System is used by Colombian financial sector entities who from their use have optimized both their profits and the productivity of human talent, since the system has allowed the generation of contingency plans to deal with a crisis due to operational ris

Consensus statement on the diagnosis, management, and treatment of angioedema mediated by Bradykinin. Part. II: treatment, follow-up, and special situations

Background: There are no previous Spanish guidelines or consensus statements on bradykinin-induced angioedema. Aim: To draft a consensus statement on the management and treatment of angioedema mediated by bradykinin in light of currently available scientifi c evidence and the experience of experts. This statement will serve as a guideline to health professionals. Methods: The consensus was led by the Spanish Study Group on Bradykinin-Induced Angioedema, a working group of the Spanish Society of Allergology and Clinical Immunology. A review was conducted of scientifi c papers on different types of bradykinin-induced angioedema (hereditary and acquired angioedema due to C1 inhibitor defi ciency, hereditary angioedema related to estrogens, angioedema induced by angiotensin-converting enzyme inhibitors). Several discussion meetings were held to reach the consensus. Results: Treatment approaches are discussed, and the consensus reached is described. Specifi c situations are addressed, namely, pregnancy, contraception, travelling, blood donation, and organ transplantation. Conclusions: A review of and consensus on treatment of bradykinin-induced angioedema is presentedIntroducción: No existen guías previas españolas sobre el manejo del angioedema mediado por bradicinina. Objetivos: Alcanzar un consenso sobre el manejo y tratamiento del angioedema mediado por bradicinina a la luz de la evidencia científi ca disponible y la experiencia de los expertos, que sirva como guía para los profesionales de la salud. Métodos: SGBA/GEAB, un grupo de trabajo de la SEAIC dirigió el consenso. Se realizó una revisión de los documentos científi cos publicados sobre los diferentes tipos de angioedema mediado por bradicinina [angioedema hereditario o adquirido por defi ciencia de inhibidor de la C1 esterasa, angioedema hereditario relacionado con estrógenos (AEH tipo III, AEH-FXII), angioedema inducido por IECA (inhibidores del enzima convertidor de angiotensina]. Hubo varias reuniones del SGBA/GEAB para alcanzar el consenso. Resultados: Se revisan y discuten los diferentes tratamientos disponibles y se describe el consenso alcanzado. Se abordan situaciones específi cas (embarazo, anticoncepción, viajes, hemodonación, trasplante de órganos). Conclusiones: Se presenta una revisión del tratamiento del angioedema mediado por bradicinina y un consenso sobre su tratamiento en EspañaDr. Teresa Caballero is a researcher with the Hospital La Paz Health Research Institute (IdiPaz) program for promoting research activities (2009