Metodologías Participativas para el Mejoramiento Genético del Frijol Común 1

Debido a que el presente informe semestral coincide con la finalizacion de la presente fase de financiamiento de dos anos por el programa de Small Grants

Self-Similarity in Random Collision Processes

Kinetics of collision processes with linear mixing rules are investigated analytically. The velocity distribution becomes self-similar in the long time limit and the similarity functions have algebraic or stretched exponential tails. The characteristic exponents are roots of transcendental equations and vary continuously with the mixing parameters. In the presence of conservation laws, the velocity distributions become universal.Comment: 4 pages, 4 figure

The significance of cephalopod beaks as a research tool: An update

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960’s, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed.Cephalopod International Advisory Counci

Single-phase five-level multilevel inverter based on a transistors six-pack module

This article introduces a single-phase five-level multilevel inverter based on six switches and two transformers. The proposed converter requires a single dc input source with low voltage. The disposition of switches makes it possible to build the converter with a transistors six-pack module off-the-shelves, traditionally used to build three-phase inverters, which simplifies the manufacturing process. The converter increases the voltage with two transformers; for that reason, it does not require an auxiliary step-up converter. The use of transformers (with the transformer’s turns ratio) allows for using the same topology for several input voltage levels. To verify the operation of the proposed multilevel inverter, a computer-based simulation was performed with PSIM, a software that considers parasitic components. The results show that the proposed converter can work properly

The fourth-order single-switch improved super-boost converter with reduced input current ripple

This paper introduces a new single switch DC-DC fourth-order boost converter. The proposed converter is the improved version of an existing converter known as the super-boost converter. The improved super-boost ISP converter achieves a smaller input current ripple than the super-boost converter when the same parameters in passive components are used. Conversely, smaller components can be used to achieve the same input current ripple, which leads to a compact and cheaper design. A comparative evaluation showed a reduction of 37.3% of stored energy in inductors to comply with a required input current ripple in comparison with the super-boost converter for a particular design. Experimental results are provided to corroborate this benefit of the ISB proposed topology

A step-up converter with large voltage gain and low voltage rating on capacitors

Step-up converters are widely used in many applications, such as renewable energy generation with photovoltaic panels and fuel cell stacks. In many cases, the required voltage gain is larger for those applications than a traditional boost converter can achieve. Several large-voltage gain converters have been recently studied. This paper introduces a converter topology in which the voltage gain is larger than a traditional boost converter. The main advantages of the proposed topology are: (i) it provides a large voltage gain without the use of an extreme duty cycle; (ii) its capacitors require a smaller voltage to be sustained compared with other, similar state-of-the-art converters; (iii) the voltage among the ground input and output is not pulsating; and (iv) it can be synthesized with commercial, off-the-shelf half-bridge packed transistors. The proposed converter can be employed in different applications, such as distributed generation and microgrids. This paper presents the steady-state analysis of the proposed converter in the continuous conduction mode, a short comparison with similar topologies, and their voltage on capacitors. Computer-based simulation results are provided to verify the principle of the proposed converter in different operating conditions

Deep Submarine Giant Scours in northern Gulf of Cadiz (offshore SW Iberia): a singular case of sedimentary and tectonic coupling?

Multi-beam swath bathymetry carried out in NW Gulf of Cadiz(offshore SW Iberia - MATESPRO campaign) revealed several intriguing morphologic features, lying at depths between -3900 and - 4700 m., in an area characterized by very shallow general slope gradients (dipping approximately 0.4 degrees). These three dimensional features are characterized by elliptical crescent shapes of kilometric length (major axis around 5 km), displaying internal escarpments up to 100 m high and slopes varying between 6 and 14 degrees.A single channel seismic profile acquired across two of these features shows that they have a sub-surface composite structure. The internal part of the crescent consists of a depression filled up with upslope prograding sedimentary units developing towards the scarp that sharply truncates the sedimentary horizons. The growth processes of these structures appears to be by retrogressive displacement of a morphological scarp and remobilization followed by deposition of the eroded material in front of the scarp, prograding towards it. This process is similar to the development of contourite bodies in which the current direction is parallel to the scarp, whilst in the present case the flow direction may be mainly perpendicular to the scarp.These units are overlain by a sub-horizontal turbidite-like sedimentary unit that partially infills the depression. A deep multi-channel seismic profile across the same structure revealed the existence of an underlying thrust, part of a major structure, the Gulf of Cadiz Accretionary Prism. These singular features are interpreted as the coupled of sedimentary and tectonic processes. It is proposed that the Deep Submarine Giant Scours formed when a local morphologic irregularity, corresponding to the bathymetric expression of movement on an underlying thrust, is enhanced by the erosional activity of turbidity and thermohaline bottom currents driven by the formation of local eddies in front of the scarp. The drift results from the re-deposition of the eroded material in the same location

First experiences with a novel farmer citizen science approach: crowdsourcing participatory variety selection through on-farm triadic comparisons of technologies (TRICOT)

Rapid climatic and socio-economic changes challenge current agricultural R&D capacity. The necessary quantum leap in knowledge generation should build on the innovation capacity of farmers themselves. A novel citizen science methodology, triadic comparisons of technologies or tricot, was implemented in pilot studies in India, East Africa, and Central America. The methodology involves distributing a pool of agricultural technologies in different combinations of three to individual farmers who observe these technologies under farm conditions and compare their performance. Since the combinations of three technologies overlap, statistical methods can piece together the overall performance ranking of the complete pool of technologies. The tricot approach affords wide scaling, as the distribution of trial packages and instruction sessions is relatively easy to execute, farmers do not need to be organized in collaborative groups, and feedback is easy to collect, even by phone. The tricot approach provides interpretable, meaningful results and was widely accepted by farmers. The methodology underwent improvement in data input formats. A number of methodological issues remain: integrating environmental analysis, capturing gender-specific differences, stimulating farmers' motivation, and supporting implementation with an integrated digital platform. Future studies should apply the tricot approach to a wider range of technologies, quantify its potential contribution to climate adaptation, and embed the approach in appropriate institutions and business models, empowering participants and democratizing science

Evaluación urodinámica y comparativa de la calidad de vida en pacientes con trastorno de vaciamiento vesical sometidos a terapia InterStim, Medtronic®

ResumenAntecedentesDesde 1980 la terapia de neuroestimulación sacra ha demostrado ser una terapia válida y alternativa en el manejo de los trastornos miccionales por patología del tracto urinario bajo, siendo sus principales indicaciones la retención urinaria idiopática, la incontinencia de urgencia y la incontinencia fecal. En nuestro país sigue siendo una terapia novedosa y no se cuenta aún con estudios que evalúen esta eficacia en términos de calidad de vida o con parámetros cuantitativos.Objetivo del estudioEstablecer la eficacia de la terapia de neuroestimulación sacra tipo InterStim, Medtronic®, en el manejo de los pacientes con trastornos de vaciamiento vesical, efectuando un análisis urodinámico y de la calidad de vida comparativo previo y posterior al tratamiento, determinando los volúmenes miccionales, los períodos de incontinencia, la satisfacción del paciente y la calidad de vida.Material y métodosDesde enero de 2010 hasta junio de 2013, en el Hospital Central Militar se realizó evaluación urodinámica y comparativa de la calidad de vida mediante el empleo del instrumento SF-36 v2 (versión mexicana) e ICIQSF, en los pacientes que presentaron trastorno de vaciamiento vesical de etiología no obstructiva y que fueron refractarios a tratamiento médico.ResultadosSe incluyeron 10 pacientes en el estudio, bajo los siguientes diagnósticos: disinergia detrusor-esfínter, vejiga hiperactiva y retención urinaria no obstructiva, ubicados por género (2 masculinos y 8 femeninos). En la totalidad de los pacientes se presentó mejoría del 50% o superior durante la fase de prueba de la terapia de neuroestimulación, y se colocó fase definitiva con los siguientes resultados: se obtuvieron resultados equivalentes al 50-65% de mejoría en los parámetros cualitativos de función física, función social y rol emocional, así como en las variables cuantitativas de volumen de vaciamiento, eficacia de vaciamiento y disminución de los períodos de incontinencia.DiscusiónComo se ha establecido a nivel de la literatura mundial, nuestros resultados fueron similares en el efecto benéfico y la eficacia en la calidad de vida e incontinencia urinaria, respectivamente, y se reportan porcentajes de éxito mayores al 50% en el cese total de los episodios de incontinencia.ConclusionesLa neuromodulación mediante la estimulación del nervio sacro es una forma exitosa de tratamiento en los trastornos de vaciamiento vesical de etiología no obstructiva y refractaria al tratamiento médico, es segura, mínimamente invasiva y de fácil aplicación, y mejora la calidad de vida de los pacientes. Sin embargo, es necesario realizar estudios aleatorizados y que consideren parámetros objetivos (urodinámicos), así como las complicaciones posibles a mediano y largo plazo en este tipo de terapia.AbstractBackgroundSince 1980, sacral neuromodulation therapy has been shown to be a valid alternative therapy in the management of urinary disorders due to lower urinary tract pathology, and its primary indications are: idiopathic urinary retention, urge incontinence, and fecal incontinence. It is still considered a novel therapy in Mexico and there are no studies using quantitative parameters that evaluate its efficacy in terms of quality of life.AimsTo establish the efficacy of the Medtronic InterStim® sacral neuromodulation therapy in the management of patients with bladder voiding disorders through urodynamic and quality of life analyses before and after treatment. Urine volume, periods of incontinence, patient satisfaction, and quality of life were determined.MethodsA comparative urodynamic and quality of life evaluation was carried out using the SF-36 v2 (Mexican version) and the ICIQSF instruments on patients presenting with nonobstructive bladder voiding disorders that were refractory to medical treatment.ResultsTen patients with the following diagnoses were included in the study: detrusor sphincter dyssynergia, overactive bladder, and nonobstructive urinary retention. Two of the patients were men and 8 were women. There was a 50% or greater improvement in all 10 patients during the test phase of the neuromodulation therapy and the definitive placement phase produced the following results: a 50-65% improvement in the qualitative parameters of physical function, social function, and emotional role, as well as in the quantitative variables of voiding volume, voiding efficacy, and reduced periods of incontinence.DiscussionOur results were similar to those established in the international literature in relation to the beneficial effect on quality of life and efficacy in urinary incontinence management; the literature reports success percentages in the complete cessation of incontinence episodes at above 50%.ConclusionsNeuromodulation through sacral nerve stimulation is a successful form of treatment of nonobstructive and medical treatment-refractory bladder voiding disorders. It is safe, minimally invasive, and easy to apply and it improves patient quality of life. Nevertheless, further randomized studies on this type of therapy need to be conducted that take into account objective parameters (urodynamics) and possible medium and long-term complications