Precoding in multigateway multibeam satellite systems

This paper considers a multigateway multibeam satellite system with multiple feeds per beam. In these systems, each gateway serves a set of beams (cluster) so that the overall data traffic is generated at different geographical areas. Full frequency reuse among beams is considered so that interference mitigation techniques are mandatory. Precisely, this paper aims at designing the precoding scheme which, in contrast to single gateway schemes, entails two main challenges. First, the precoding matrix shall be separated into feed groups assigned to each gateway. Second, complete channel state information (CSI) is required at each gateway, leading to a large communication overhead. In order to solve these problems, a design based on a regularized singular value block decomposition of the channel matrix is presented so that both intercluster (i.e., beams of different clusters) and intracluster (i.e., beams of the same cluster) interference is minimized. In addition, different gateway cooperative schemes are analyzed in order to keep the inter-gateway communication low. Furthermore, the impact of the feeder link interference (i.e., interference between different feeder links) is analyzed and it is shown both numerically and analytically that the system performance is reduced severely whenever this interference occurs even though precoding reverts this additional interference. Finally, multicast transmission is also considered. Numerical simulations are shown considering the latest fixed broadband communication standard DVB-S2X so that the quantized feedback effect is evaluated. The proposed precoding technique results to achieve a performance close to the single gateway operation even when the cooperation among gateways is low.Postprint (author's final draft

Precoding in multigateway multibeam satellite systems

This paper considers a multigateway multibeam satellite system with multiple feeds per beam. In these systems, each gateway serves a set of beams (cluster) so that the overall data traffic is generated at different geographical areas. Full frequency reuse among beams is considered so that interference mitigation techniques are mandatory. Precisely, this paper aims at designing the precoding scheme which, in contrast to single gateway schemes, entails two main challenges. First, the precoding matrix shall be separated into feed groups assigned to each gateway. Second, complete channel state information (CSI) is required at each gateway, leading to a large communication overhead. In order to solve these problems, a design based on a regularized singular value block decomposition of the channel matrix is presented so that both intercluster (i.e., beams of different clusters) and intracluster (i.e., beams of the same cluster) interference is minimized. In addition, different gateway cooperative schemes are analyzed in order to keep the inter-gateway communication low. Furthermore, the impact of the feeder link interference (i.e., interference between different feeder links) is analyzed and it is shown both numerically and analytically that the system performance is reduced severely whenever this interference occurs even though precoding reverts this additional interference. Finally, multicast transmission is also considered. Numerical simulations are shown considering the latest fixed broadband communication standard DVB-S2X so that the quantized feedback effect is evaluated. The proposed precoding technique results to achieve a performance close to the single gateway operation even when the cooperation among gateways is low.Postprint (author's final draft

Comparative study of lactation curves and milk quality in Holstein versus Swedish Red and White-Holstein Cross Cows

The objective of this study reported in this research paper was to compare the lactation curves of the production of milk, fat, protein, percentages of fat and protein, and somatic cell score in purebred Holstein (H) cows and Swedish Red and White (SRW) - Holstein (SxH) crossbred cows in the south-central region of the province of Cordoba, Argentina. The data set consisted of 32847 herd-test records from 1244 purebred H cows and 310 SRW x H crossbred cows, from three commercial dairy farms with cows of first to fifth or more lactations. The curves were modeled using the fourth-order Legendre orthogonal polynomials. In this study, the data of production of milk, fat production, protein production, percentage of fat, percentage of protein and somatic cell score (SCS) were analyzed. Purebred H cows had significantly higher milk production, more fat production and higher protein production levels than did SxH crossbred cows. However, SxH crossbred cows produced milk that had a higher percentage of fat and a higher percentage protein than did purebred H cows. In none of the lactations did somatic cell score differ significantly between the two breed groups. The results of our study showed that, SxH crossbred cows had significantly higher percentages of fat and protein; however, purebred H cows were significantly superior to SxH crossbred cows for the production of 305-d milk, fat, and protein. Mammary health, expressed in SCS, did not differ significantly between the two breed groups. Thus, suggest that crossbreeding Holstein purebred cows with SRW bulls can improve the composition of milk solids without affecting mammary health and, in this way, compensate substantially for any potential loss in the production and/or quality of the milk of the crossbred cows compared to H purebred cows.Fil: Pipino, Diego. Agroveterinaria Pipino; Argentina. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; ArgentinaFil: Piccardi, Mónica Belén. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Desarrollo Rural. Area de Estadística y Biometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lembeye, Felipe. Soprole. Gerencia de Abastecimiento. Departamento Agropecuario; ChileFil: Lopez Villalobos, Nicolas. Massey University; Nueva ZelandaFil: Vazquez, Maria Isabel. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Polymorphic Students

Objective: In an effort to break away from the stale classifications of community college students that stem from the hegemonic perspective of previous literature, this work utilizes the perceptions of community college practitioners to demonstrate new ways of understanding the identities of community college students. Method: By utilizing Gee’s identity theory and Grillo’s theory of intersectionality, we analyze interviews with community college practitioners from three different community colleges on the West coast of the United States to answer these questions: What identities (i.e., natural, institutional, and discursive) do faculty and administrators recognize in community college students? In what ways do community college faculty and administrators describe and conceptualize community college students? Findings: First, community college student identities are intricate and have changed with time; there are two different institutional views held by organizational members—the educational view and the managerial view—which both shape the construction of student identities and play a prominent role in determining which students are disadvantaged. Second, organizational members constructed meanings of student achievement and value (i.e., attributes or outcomes of the ideal student, or what policy makers and institutions refer to as success) according to organizational priorities and perspectives. Conclusion: This investigation encapsulates and elucidates the portrayals and understandings of community college students held by community college administrators and faculty as a means to acknowledge the diverse identities among these students. Scholars and practitioners are encouraged to acknowledge the polymorphic identities of this diverse population to improve scholarship and practice

Synthesis and characterization of new carrier molecule-antibiotic conjugates for its study in the diagnosis of drug allergy

Motivation: Quinolones represent an important category of antibiotics. Among them, fluoroquinolones (FQs) constitute the most important group. FQs present a wide range of activity against gram-positive and gram-negative bacterias.Despite their tremendous benefits against bacterial infections and the fact that FQ hypersensitivity reactions are considered unusual, recently there has been an increase of the number of reported cases of hypersensitivity to FQs.There are two types of hypersensitivity reactions, namely immediate reactions, which appear within one hour of the drug intake, and delayed reactions, which appear more than one hour after the drug intake.Immediate reactions are the most frequent reactions, with symptoms like anaphylaxis or uticaria. The most common FQs are ciprofloxacin, moxifloxacin and levofloxacin.The methods of diagnosis to FQ hypersensitivity are usually complex, because the clinical history is usually unreliable, skin tests cause false-positives and the drug provocation test is a very risky method.In vitro tests are being developed, but there are currently no validated commercial tests.The goal of our work is to make a new solid phase for performing immunoassays, able to be employed in the diagnosis of hypersensitivity to FQs (siprofloxacin, moxifloxacin and levofloxacin) by means of in vitro test. In these systems, the solid phase is conjugated to the drug-carrier protein adduct, which is specifically recognized and bonded by specific IgE from patients.Methods: In order to optimize the conjugation of FQs to carrier protein, the reaction was first optimized with a simple primary amine molecule, like butylamine. After optimization of the reaction in solution, the same reaction is extrapolated to the solid phase.Since ciprofloxacin and moxifloxacin have two reactive groups, the conjugation was performed with both groups, which will allow us to evaluate which part of the structure is recognized by specific IgE antibodies and, therefore, is involved in the allergic proccess

Eines per al desenvolupament de competències d'enginyeria en un assignatura d'intel·ligència artificial

En aquesta comunicació recollim l'experiència de tres anys en l'adaptació al nou model educatiu en una assignatura de 4rt d'enginyeria informàtica. L'objectiu ha estat el d'aconseguir una metodologia que emfatitzi les competències dels enginyers en una assignatura orientada a la resolució de problemes com és la Intel·ligència Artificial. Les competències sobre les que hem incidit més són: la capacitat d'anàlisi de problemes contextualitzats, la generalització dels problemes d'acord amb els coneixement adquirits prèviament, la capacitat de plantejar solucions viables, l'avaluació de les solucions i l'anàlisi del seu rendiment. Complementàriament, això s'acompanya del treball en competències transversals com ara el treball en equip i la defensa en públic de les solucions, i l'anglès. Per dur-ho a terme a les classes de teoria es treballa totalment orientat a la resolució de casos i s'han dissenyat noves sessions de problemes i pràctiques. En aquestes sessions s'han augmentat el nombre de grups per a permetre un seguiment real dels alumnes. Els problemes estan pensats per a potenciar la capacitat d'anàlisi amb enunciats de difícil o, fins i tot, de solució desconeguda, per a potenciar l'esperit crític i la participació activa a classe. La defensa pública de la feina es duu a terme, després d'una classe teòrica sobre la matèria, en les sessions de practiques,on es simula un projecte real de principi a fi. La feina en equip es potencia tan en problemes com en practiques amb grups de 2 a 5 alumnes. L'ús de la llengua anglesa s'ha introduït exitosament el darrer any, tant en els enunciats, en les sessions de problemes, així com a les presentacions dels estudiants.In this paper we review a 3 years experience on the adaptation of a subject to the new education model. We are working on the Artificial Intelligence subject that is hold during the fourth year of the Computer Science degree. The general goal of this adaptation has been to reach a new methodology that focuses on general engineering competences in the framework of a subject that is completely problem-based, this is Artificial Intelligence. The main competences we have focused the more are: the analysis of problems in a real context, the generalisation of solutions according to previously learnt techniques, the ability to plan feasible solutions, the evaluation of proposed solutions and the analysis of their performance. Complementary, we add the work on transversal competences such as, working cooperatively in a team, presenting and defending the proposed solutions and English speaking. To reach these goals we propose to work in a completely problem-based methodology in the theoretical part of the subject. The part of the subject devoted to solve problems is dealt by working in seminars with a reduced number of students that work in an interactive way. Finally, the practical part of the subject is oriented to simulate the development of a real project, that is solved cooperatively in groups of 4 or 5 students that meet in different sessions. The students design and implement a new solution to a problem statement; in the end they defend their own solution in a viva in front of their colleagues. The use of the English language is inserted in different points of the course

Definición empírica de la relación agua / cemento efectiva en morteros con árido reciclado en función de la absorción

The use of recycled aggregates from construction and demolition wastes for the manufacture of mortars and concretes is a subject of great interest from the point of view of sustainable construction since it can reduce the exploitation of quarries replacing natural aggregate by recycled aggregate and it can reduce the volume of wastes in landfills. In order to study the influence of recycled aggregate on concrete and mortar strength, the effective water/cement ratio must be the same in concretes or mortars compared. The effective water/cement ratio is defined as the amount of water available to react with the cement of the mixture. Discrepancies among authors arise in the definition of how much is the amount of available water, which depends on the absorption and moisture of the aggregates at the time of the batch. Therefore, in this research, an experimental study is developed empirically to find the amount of water which reacts with the cement mortar in various mixtures with different ratios of recycled aggregate depending on the absorption of the aggregates. Subsequently, the relations between the amount of water which doesn’t react with the cement and aggregate absorption of each of the mixtures were analyzed. Finally, a definition of the effective water/cement ratio depending on absorption is proposed, based on the empirical study developed.La utilización de áridos reciclados procedentes de construcción y demolición, para la fabricación de morteros y hormigones es un tema de gran interés desde el punto de vista de la construcción sostenible puesto que, además de disminuir la explotación de las canteras al sustituir el árido natural por árido reciclado, también se reduce el volumen de residuos depositados en vertederos. Para poder estudiar la influencia que tiene el uso de árido reciclado en la resistencia de los hormigones y morteros, es necesario que la relación agua/cemento efectiva sea a misma en todas las mezclas comparadas, La relación agua/cemento efectiva se define como la cantidad de agua disponible que reacciona con el cemento de la mezcla. Las discrepancias entre autores surgen en la definición de cuál es esa “cantidad de agua disponible”, La cantidad de agua disponible que reacciona con el cemento depende de la absorción de los áridos Por ello, en esta investigación, se desarrolla un estudio experimental para hallar de forma empírica la cantidad de agua que reacciona con el cemento en varias mezclas de mortero con distintos porcentajes de sustitución de árido reciclado, en función de la absorción de los áridos. Posteriormente se analiza qué relaciones existen entre la cantidad de agua que no reacciona con el cemento y el agua total de absorción de los áridos de cada una de las mezclas. Finalmente se propone una definición de la relación agua/cemento efectiva en función de la absorción basada en este estudio empírico

Molecular and Structural Parallels between Gluten Pathogenic Peptides and Bacterial-Derived Proteins by Bioinformatics Analysis

Gluten-related disorders (GRDs) are a group of diseases that involve the activation of the immune system triggered by the ingestion of gluten, with a worldwide prevalence of 5%. Among them, Celiac disease (CeD) is a T-cell-mediated autoimmune disease causing a plethora of symptoms from diarrhea and malabsorption to lymphoma. Even though GRDs have been intensively studied, the environmental triggers promoting the diverse reactions to gluten proteins in susceptible individ-uals remain elusive. It has been proposed that pathogens could act as disease-causing environmental triggers of CeD by molecular mimicry mechanisms. Additionally, it could also be possible that unrecognized molecular, structural, and physical parallels between gluten and pathogens have a relevant role. Herein, we report sequence, structural and physical similarities of the two most relevant gluten peptides, the 33-mer and p31-43 gliadin peptides, with bacterial pathogens using bioinformatics going beyond the molecular mimicry hypothesis. First, a stringent BLASTp search using the two gliadin peptides identified high sequence similarity regions within pathogen-derived proteins, e.g., extracellular proteins from Streptococcus pneumoniae and Granulicatella sp. Second, molecular dynamics calculations of an updated α-2-gliadin model revealed close spatial localization and solvent-exposure of the 33-mer and p31-43 peptide, which was compared with the pathogen-related proteins by homology models and localization predictors. We found putative functions of the identified pathogen-derived sequence by identifying T-cell epitopes and SH3/WW-binding domains. Finally, shape and size parallels between the pathogens and the superstructures of gliadin peptides gave rise to novel hypotheses about activation of innate immunity and dysbiosis. Based on our structural findings and the similarities with the bacterial pathogens, evidence emerges that these pathologically relevant gluten-derived peptides could behave as non-replicating pathogens opening new research questions in the interface of innate immunity, microbiome, and food research.Fil: Vazquez, Diego Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Schilbert, Hanna M.. Universitat Bielefeld; AlemaniaFil: Dodero, Veronica Isabel. Universitat Bielefeld; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Evidence of the presence of calcium/calmodulin-dependent protein kinase IV in human sperm and its involvement in motility regulation

The mechanisms involved in the regulation of mammalian sperm motility are not well understood. Calcium ions (Ca(2+)) have been suggested to play a key role in the maintenance of motility; nevertheless, how Ca(2+) modulates this process has not yet been completely characterized. Ca(2+) can bind to calmodulin and this complex regulates the activity of multiple enzymes, including Ca(2+)/calmodulin-dependent protein kinases (CaM kinases). Results from this study confirmed that the presence of Ca(2+) in the incubation medium is essential for maintaining human sperm motility. The involvement of CaM kinases in Ca(2+) regulation of human sperm motility was evaluated using specific inhibitors (KN62 and KN93) or their inactive analogues (KN04 and KN92 respectively). Sperm incubation in the presence of KN62 or KN93 led to a progressive decrease in the percentage of motile cells; in particular, incubation with KN62 also reduced sperm motility parameters. These inhibitors did not alter sperm viability, protein tyrosine phosphorylation or the follicular fluid-induced acrosome reaction; however, KN62 decreased the total amount of ATP in human sperm. Immunological studies showed that Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) is present and localizes to the human sperm flagellum. Moreover, CaMKIV activity increases during capacitation and is inhibited in the presence of KN62. This report is the first to demonstrate the presence of CaMKIV in mammalian sperm and suggests the involvement of this kinase in the regulation of human sperm motility.Fil: Marin Briggiler, Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Jha, Kula N.. University of Virginia; Estados UnidosFil: Chertihin, Olga. University of Virginia; Estados UnidosFil: Buffone, Mariano Gabriel. Laboratorio de Estudios en Reproducción; ArgentinaFil: Herr, John C,. University of Virginia; Estados UnidosFil: Vazquez, Monica Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Visconti, Pablo E.. University of Massachussets; Estados Unido