Summary
A review is presented of genetic strategies deployed in a 3‐yr project on drought tolerance in barley. Data were collected on genetic, physiological and agronomic traits in non‐irrigated and ...irrigated field trials in Egypt, Morocco and Tunisia. A wide range of barley germplasm (developed from African and European cultivars, adapted landraces and wild barleys) was tested, and positive traits were found in each gene pool. The contrasting environments of the three North African countries had major effects on plant/genotype performance. Genetic effects were also detected, as were genotype × environment interactions.
A range of strategies were deployed to investigate the physiology and genetics of quantitative traits associated with field performance. Quantitative trait locus (QTL) analysis was performed using backcross lines, recombinant inbred lines and doubled haploid mapping populations. A detailed genetic map was generated in the Tadmor × (ER/Apm) recombinant inbred lines, an important mapping population specifically developed by ICARDA (Centre for Agricultural Research in Dry Areas) and CIMMYT (International Maize and Wheat Improvement Center) to study drought. Quantitative trait loci (QTLs) for grain yield and other important morphological and physiological traits were also identified in a population of doubled haploids derived from F2BCj plants from a cross between a cultivar and a wild barley accession. Significantly, the wild parental line was found to contribute a number of positive alleles for yield.
Effects of major developmental genes could explain many of the responses observed. QTLs were found to cluster around major genes controlling flowering time (sghI), plant stature (sdwI and arie.GP) and ear type (vrsl), and it is highly likely that the associations represent pleiotropic effects. Some QTLs were associated with candidate genes such as dehydrins and rubisco activase. One of the most significant results was the identification and generation of material that out performed the best local standards in the three participating North African countries; the selected lines have now entered local breeding programmes. The strategies adopted provided information on physiological traits, genotypes and genetic markers that could be used for marker‐assisted selection. Target QTLs and their associated genetic markers may be deployed in marker assisted selection programmes to match crop phenology to the field environment.
State estimation for a class of non-linear, continuous-time dynamic systems affected by disturbances is investigated. The estimator is assigned a given structure that depends on an innovation ...function taking on the form of a ridge computational model, with some parameters to be optimized. The behaviour of the estimation error is analysed by using input-to-state stability. The design of the estimator is reduced to the determination of the parameters in such a way as to guarantee the regional exponential stability of the estimation error in a disturbance-free setting and to minimize a cost function that measures the effectiveness of the estimation when the system is affected by disturbances. Stability is achieved by constraining the derivative of a Lyapunov function to be negative definite on a grid of points, via the penalization of the constraints that are not satisfied. Low-discrepancy sampling techniques, typical of quasi-Monte Carlo methods, are exploited in order to reduce the computational burden in finding the optimal parameters of the innovation function. Simulation results are presented to investigate the performance of the estimator in comparison with the extended Kalman filter and in dependence of the complexity of the computational model and the sampling coarseness.
The identification of quantitative trait loci (QTLs) for root traits can provide useful indications on their genetic basis and the associated effects on grain yield under different water regimes. ...Furthermore, the availability of molecular markers linked to QTLs controlling variation for root traits and grain yield will allow for the implementation of marker-assisted selection to improve productivity. In maize (Zea mays L.), four mapping populations have been investigated to locate QTLs for root traits under controlled conditions and/or in the field. A comparative analysis of the QTL results was carried out based on the availability of molecular markers common to the investigated populations and the UMC maize reference map. Several chromosome regions affected root traits in two or even three populations. A number of these regions also affected grain yield under well-watered and/or drought-stressed conditions. The most important QTL effects were detected on chromosome bins 1.03, 1.06, 1.08, 2.03, 2.04, 7.02, 8.06 and 10.04. Exploiting the syntenic information available for maize and rice, a number of QTLs for root traits described in rice were found to map in regions syntenic to a number of the listed maize chromosome bins (e.g., bin 2.04). The development of near isogenic lines (NILs) for the most important QTLs will allow to investigate whether the concomitant effects of the QTLs on root traits and grain yield are due to linkage and/or pleiotropy and, ultimately, may offer the opportunity to clone the genes underlying such QTLs. Although QTL analysis remains a resource-demanding undertaking, its integration with genomics and post-genomics approaches will play an increasingly important role for the identification of genes affecting root characteristics and grain yield in maize and for harnessing the favourable allelic variation at such loci.
Abscisic acid (ABA) concentration is a quantitatively inherited trait which plays a pivotal role in the response of plants to drought stress. A recent study identified 17 quantitative trait loci ...(QTLs) controlling bulk-leaf ABA concentration (L-ABA) in a maize (Zea mays L.) population of 80 F4 random families tested for two years under droughted field conditions. Sixteen of the QTL regions influencing L-ABA also harboured QTLs for one or more of the following traits: stomatal conductance, a drought sensitivity index, leaf temperature, leaf relative water content, anthesis-silking interval, and grain yield. The analysis of the effects of each QTL region on the investigated traits indicated that L-ABA mainly represented an indicator of the level of drought stress experienced by the plant at the time of sampling because an increase in L-ABA was most commonly associated with a decrease in both stomatal conductance and grain yield as well as an increase in leaf temperature. Opposite results were observed at one QTL region on chromosome 7 near the RFLP locus asg8. A model is presented to interpret these contrasting results in terms of pleiotropic effects.
•A game-theoretic approach is used to measure centrality of nodes.•The approach is based on cooperative games with transferable utility.•The approach evaluates nodes based on their joint contribution ...to the network.•Suitable utility functions are used to integrate demand within the analysis.
Network connectivity is an important aspect of any transportation network, as the role of the network is to provide a society with the ability to easily travel from point to point using various modes. A basic question in network analysis concerns how “important” each node is. An important node might, for example, greatly contribute to short connections between many pairs of nodes, handle a large amount of the traffic, generate relevant information, represent a bridge between two areas, etc. In order to quantify the relative importance of nodes, one possible approach uses the concept of centrality. A limitation of classical centrality measures is the fact that they evaluate nodes based on their individual contributions to the functioning of the network. The present paper introduces a game theory approach, based on cooperative games with transferable utility. Given a transportation network, a game is defined taking into account the network topology, the weights associated with the arcs, and the demand based on an origin-destination matrix (weights associated with nodes). The network nodes represent the players in such a game. The Shapley value, which measures the relative importance of the players in transferable utility games, is used to identify the nodes that have a major role. For several network topologies, a comparison is made with well-known centrality measures. The results show that the suggested centrality measures outperform the classical ones, and provide an innovative approach for transportation network analysis.
El tratamiento en el cáncer de recto ha progresado en la última década. Hoy es factible ofrecer una cirugía con preservación de esfínteres, realizando anastomosis colorrectales bajas o anastomosis ...coloanales. Esto ha determinado que muchos pacientes desarrollen disfunción intestinal que puede llegar a ser severa, agrupando una serie de alteraciones que se conocen como síndrome de resección anterior baja.
Efectuar una adaptación cultural de la versión 1.0 en español neutro del cuestionario acerca de la función intestinal o Low Anterior Resection Syndrome Score (LARS Score), efectuando traducción, comparación de traducciones, traducción inversa y prueba piloto.
Los resultados obtenidos de la prueba piloto revelan que la población encuestada logró comprender el instrumento, por lo que no se realizaron modificaciones posteriores.
Se cuenta con una versión adaptada del cuestionario LARS para ser usada en Chile, la cual puede someterse a procesos de validación y establecer las características psicométricas para ser usada en pacientes con cáncer de recto operados.
The treatment of rectal cancer has progressed in the past decade. Nowadays, it's feasible to provide sphincter sparing surgery with low colorectal anastomosis or coloanal anastomosis. This has determined that many patients develop intestinal dysfunctions that can become severe, grouping a number of disorders known as low anterior resection syndrome.
To perform a cultural adaptation of the version 1.0 questionnaire about bowel function or Low Resection Syndrome Score (LARS Score) in neutral Spanish, making a translation, comparing translations, back translation and pilot test.
The results of the pilot test showed that the population surveyed understood the instrument, so that no further modifications were made.
We now have an adapted version of the LARS questionnaire for use in Chile, which can undergo validation processes to establish the psychometric characteristics for use in patients with rectal cancer surgery.
The study of direct ancestry relationships provides information with which to determine essential derivation. SSR profiles were used to determine the pattern of relatedness among 134 durum wheat ...accessions, representing the most important modern durum wheat gene pools. Simple sequence repeat (SSR)- and amplified fragment length polymorphism (AFLP)-based genetic similarities among cultivars with accurate pedigrees were compared with pedigree-based coefficients of parentage. Sizeable departures of molecular similarities from the expected ones were observed, indicating the unreliability of inferring the pattern of genetic relatedness from the coefficient of parentage. Case studies consisting of parent-progeny cultivar trios and pairs, identified on the basis of their registered pedigree, were studied to evaluate the probability of ancestry of each progeny cultivar, compared with all the remaining accessions. Rare alleles and haplotype sharing were also explored. When the results did not agree with the registered parentages, SSR markers provided information with which to identify the most probable parents (or the corresponding “breeding lineages”) in the collection.
La resección total del mesorrecto por vía transanal es un abordaje híbrido que combina el uso de una plataforma transanal y laparoscopia convencional.
Realizar el análisis de casos seleccionados con ...cáncer de recto medio e inferior en los cuales se utilizó un abordaje transanal combinado para su resolución y la descripción de la técnica quirúrgica.
Corresponde a una serie prospectiva de pacientes con diagnóstico de cáncer de recto de tercio medio e inferior con resección mesorrectal asistida por monopuerto endoanal entre octubre de 2012 y diciembre de 2015, en Hospital Clínico Universidad de Chile. Se utilizó estadística descriptiva para el análisis de los datos.
Fueron sometidos a cirugía por cáncer de recto medio e inferior un total de 29 pacientes utilizando monopuerto transanal. De estos, 22 fueron de sexo masculino y 7 de sexo femenino, con edad promedio de 55,5 años e IMC de 26,4. La distancia media al margen anal fue 4,8cm. Todos recibieron neoadyuvancia. Se realizaron 17 Ta-TME (58,6%) y 12 Ta-TME con abordaje interesfintérico (41,4%). La anastomosis fue coloanal manual en 15 pacientes (51,7%) y grapada en 14 (48,3%). El abordaje laparoscópico se utilizó en 26 pacientes y el abierto en 3, registrando 4 conversiones (15,4%). El tiempo operatorio promedio fue de 282min. La estadía hospitalaria media fue de 9 días.
El monopuerto endoanal aparece como una herramienta útil en la disección total del mesorrecto por su seguridad y factibilidad. Creemos que es necesaria la realización de trabajos prospectivos aleatorizados, donde es relevante la comparación de resultados oncológicos y funcionales a largo plazo.
Transanal total mesorectal excision is a hybrid approach that combines the use of a conventional laparoscopic and a transanal platform.
To conduct an analysis of selected cases with medium and lower rectal cancer, were a combined transanal approach was used and description of the surgical technique.
Prospective series of patients diagnosed with middle and lower third rectal cancer with mesorectal resection assisted by endoanal single port, between October 2012 and December 2015 at University of Chile Clinical Hospital. Descriptive statistics were used for data analysis.
A total of 29 patients underwent surgery for middle and lower rectal cancer using a transanal single port. Gender distribution was 22 male and 7 female patients, with a mean age of 55.5 years and a mean BMI of 26.4. The mean distance from the anal margin was 4.8cm. All patients received neoadjuvant therapy. The surgeries performed were 17 Ta-TME (58.6%) and 12 Ta-TME with intersphincteric approach (41.4%). The colo-anal anastomosis was hand sewn in 15 patients (51.7%), and stapled in 14 (48.3%). The laparoscopic approach was used in 26 patients and the open approach in 3, with 4 conversions (15.4%). The mean operative time was 282min. The mean hospital stay was 9 days.
The endoanal single port appears as a useful tool in total mesorectal dissection for its safety and feasibility. We believe we need randomized prospective studies, where comparison of oncological and functional long-term results is relevant.
A search for cosmic neutrino sources using the data collected with the ANTARES neutrino telescope between early 2007 and the end of 2015 is performed. For the first time, all neutrino ...interactions-charged- and neutral-current interactions of all flavors-are considered in a search for point-like sources with the ANTARES detector. In previous analyses, only muon neutrino charged-current interactions were used. This is achieved by using a novel reconstruction algorithm for shower-like events in addition to the standard muon track reconstruction. The shower channel contributes about 23% of all signal events for an E−2 energy spectrum. No significant excess over background is found. The most signal-like cluster of events is located at (α,δ)=(343.8°,23.5°) with a significance of 1.9σ. The neutrino flux sensitivity of the search is about E2dΦ/dE=6×10−9 GeV cm−2 s−1 for declinations from −90° up to −42°, and below 10−8 GeV cm−2 s−1 for declinations up to 5°. The directions of 106 source candidates and 13 muon track events from the IceCube high-energy sample events are investigated for a possible neutrino signal and upper limits on the signal flux are determined.
The design of state estimators for nonlinear dynamic systems affected by disturbances is addressed in a functional optimization framework. The estimator contains an innovation function that has to be ...chosen within a suitably defined class of functions in such a way to minimize a cost functional given by the worst-case ratio of the Lagrangian (script capital L) p norms of the estimation error and the disturbances. Since this entails an infinite-dimensional optimization problem that under general hypotheses cannot be solved analytically, an approximate solution is sought by minimizing the cost functional over linear combinations of simple "basis functions," represented by computational units with adjustable parameters. The selection of the parameters is made by solving a constrained nonlinear programming problem, where the constraints are given by pointwise conditions that ensure the well-definiteness of the functional and the existence of a solution. Penalty terms are introduced in the cost function to account for constraints imposed on points that result from sampling the sets to which the trajectories of the state and of the estimation error belong. To ensure an efficient covering of the sets, low-discrepancy sampling techniques are exploited that generate samples deterministically spread in a uniform way, without leaving regions of the space undersampled. PUBLICATION ABSTRACT
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