Variation of grain nitrogen content in relation with grain yield in old and modern Spanish wheats grown under a wide range of agronomic conditions in a Mediterranean region

Wheat yield and grain nitrogen concentration (GNC; mg N/g grain) are frequently negatively correlated. In most growing conditions, this is mainly due to a feedback process between GNC and the number of grains/m2. In Mediterranean conditions, breeders may have produced cultivars with conservative grain set. The present study aimed at clarifying the main physiological determinants of grain nitrogen accumulation (GNA) in Mediterranean wheat and to analyse how breeding has affected them. Five field experiments were carried out in north-eastern Spain in the 2005/06 and 2006/ 07 growing seasons with three cultivars released at different times and an advanced line. Depending on the experiment, source-sink ratios during grain filling were altered by reducing grain number/m2 either through pre-anthesis shading (unshaded control or 0.75 shading only between jointing and anthesis) or by directly trimming the spikes after anthesis and before the onset of the effective grain filling period (un-trimmed control or spikes halved 7–10 days after anthesis). Grain nitrogen content (GN content ; mg N/grain) decreased with the year of release of the genotypes. As the number of grains/m2 was also increased by breeding there was a clear dilution effect on the amount of nitrogen allocated to each grain. However, the increase in GN content in old genotypes did not compensate for the loss in grain nitrogen yield (GNY) due to the lower number of grains/m2. GN content of all genotypes increased (increases ranged from 0.13 to 0.40 mg N/grain, depending on experiment and genotype) in response to the post-anthesis spike trimming or pre-anthesis shading. The degree of source-limitation for GNA increased with the year of release of the genotypes (and thus with increases in grain number/m2) from 0.22 (mean of the four manipulative experiments) in the oldest cultivar to 0.51 (mean of the four manipulative experiments) in the most modern line. It was found that final GN content depended strongly on the source-sink ratio established at anthesis between the number of grains set and the amount of nitrogen absorbed at this stage. Thus, Mediterranean wheat breeding that improved yield through increases in grain number/m2 reduced the GN content by diluting a rather limited source of nitrogen into more grains. This dilution effect produced by breeding was further confirmed by the reversal effect produced by grain number/m2 reductions due to either pre-anthesis shading or post-anthesis spike trimming.

Self-consistent theory of current and voltage noise in multimode ballistic conductors

Electron transport in a self-consistent potential along a ballistic two-terminal conductor has been investigated. We have derived general formulas which describe the nonlinear current-voltage characteristics, differential conductance, and low-frequency current and voltage noise assuming an arbitrary distribution function and correlation properties of injected electrons. The analytical results have been obtained for a wide range of biases: from equilibrium to high values beyond the linear-response regime. The particular case of a three-dimensional Fermi-Dirac injection has been analyzed. We show that the Coulomb correlations are manifested in the negative excess voltage noise, i.e., the voltage fluctuations under high-field transport conditions can be less than in equilibrium.

El bosc dels fartets o la història d'una depuradora ecològica

Treball de recerca realitzat per una alumna d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. Aquest treball té per objectiu plantejar el disseny d’una depuradora ecològica i un petit bosc de ribera amb la finalitat de divulgar i reivindicar el paper crucial que juguen les zones humides en el gran ecosistema de la Terra. Davant l’imminent esgotament de les principals energies fòssils i la manca de recursos tant bàsics com l’aigua, es pretén insistir en els molts avantatges d’importar la capacitat depuradora de les zones humides com a tecnologia alternativa per tractar aigües residuals industrials, agrícoles i urbanes, amb una despesa energètica pràcticament nul•la i uns beneficis ecològics, econòmics i de cost de la oportunitat més que evidents. El reciclatge d’aigües residuals es presenta com un dels reptes més importants de les societats actuals. La denominada fitodepuració aprofita el poder refinador de la vegetació present en les zones humides per reduir o eliminar contaminants de l’aigua mitjançant una sèrie de complexos processos biològics i fisicoquímics que la natura, en la seva dinàmica perfecte, ha dissenyat durant 4500 milions d anys. I és en base a aquestes qualitats depuradores d’aquests ecosistemes aquàtics que sorgeix la figura de l’aiguamoll artificial.

Consolidació de la Plataforma COMalaWEB com a eina Web d'autoaprenentatge per a l'EEES

La plataforma d’e-learning: COMalaWEB és una eina multimedia de suport a l’estudi, l’experimentació i l’adquisició de tècniques d’autoaprenentatge. COMalaWEB s’ofereix com a punt de trobada entre estudiants, professors i altres professionals relacionats amb el mon de les telecomunicacions i/o de la docència universitària. Mitjançant el present projecte s’ha dut a terme la consolidació de la plataforma COMalaWEB com a eina WWW d'autoaprenentatge per a l'EEES (Estudis de Bachelor i de Màster): Dins de la plataforma s’hi ha integrat un Laboratori Virtual per a comunicacions analògiques i digitals (LaViCAD) que ofereix activitats experimentals amb un gran ventall de possibilitats que van des de les demostracions teòriques fins a l’emulació de sistemes de comunicacions quotidians com per exemple la televisió digital o el sistema Wifi dels sistemes WLAN. L’altre gran component de la plataforma es la base de dades de continguts empaquetada en unitats bàsiques anomenades objectes de coneixement, organitzada en cursos, integren tant continguts teòrics com un conjunt d’exercicis proposats per a aprofundir cadascun dels temes tractats. Amb l’actual projecte s’ha treballat en les següents línies d’actuació: - Integració dels simuladors del laboratori LAVICAD a la plataforma d’autoaprenentatge. - Creació de base de dades de recursos docents basats en paquets SCORM per a oferir materials docents de tipus teòric i col·leccions d’exercicis resolts en el marc de les diferents assignatures participants en el projecte. - Creació de base de dades de tipus qüestionari per a oferir exercicis a treballar en el marc de les diferents assignatures participants en el projecte. - Inserció de metodologies docents basades en els anteriors recursos en diferents assignatures d’estudis d’enginyeria i de màster.

Using a Parameterization of a Radiative Transfer Model to Build High-Resolution Maps of Typical Clear-Sky UV Index in Catalonia, Spain

To perform a climatic analysis of the annual UV index (UVI) variations in Catalonia, Spain (northeast of the Iberian Peninsula), a new simple parameterization scheme is presented based on a multilayer radiative transfer model. The parameterization performs fast UVI calculations for a wide range of cloudless and snow-free situations and can be applied anywhere. The following parameters are considered: solar zenith angle, total ozone column, altitude, aerosol optical depth, and single-scattering albedo. A sensitivity analysis is presented to justify this choice with special attention to aerosol information. Comparisons with the base model show good agreement, most of all for the most common cases, giving an absolute error within 0.2 in the UVI for a wide range of cases considered. Two tests are done to show the performance of the parameterization against UVI measurements. One uses data from a high-quality spectroradiometer from Lauder, New Zealand [45.04°S, 169.684°E, 370 m above mean sea level (MSL)], where there is a low presence of aerosols. The other uses data from a Robertson–Berger-type meter from Girona, Spain (41.97°N, 2.82°E, 100 m MSL), where there is more aerosol load and where it has been possible to study the effect of aerosol information on the model versus measurement comparison. The parameterization is applied to a climatic analysis of the annual UVI variation in Catalonia, showing the contributions of solar zenith angle, ozone, and aerosols. High-resolution seasonal maps of typical UV index values in Catalonia are presented

Characterization and evolution of the novel gene family FAM90A in primates originated by multiple duplication and rearrangement events

Genomic plasticity of human chromosome 8p23.1 region is highly influenced by two groups of complex segmental duplications (SDs), termed REPD and REPP, that mediate different kinds of rearrangements. Part of the difficulty to explain the wide range of phenotypes associated with 8p23.1 rearrangements is that REPP and REPD are not yet well characterized, probably due to their polymorphic status. Here, we describe a novel primate-specific gene family, named FAM90A (family with sequence similarity 90), found within these SDs. According to the current human reference sequence assembly, the FAM90A family includes 24 members along 8p23.1 region plus a single member on chromosome 12p13.31, showing copy number variation (CNV) between individuals. These genes can be classified into subfamilies I and II, which differ in their upstream and 5′-untranslated region sequences, but both share the same open reading frame and are ubiquitously expressed. Sequence analysis and comparative fluorescence in situ hybridization studies showed that FAM90A subfamily II suffered a big expansion in the hominoid lineage, whereas subfamily I members were likely generated sometime around the divergence of orangutan and African great apes by a fusion process. In addition, the analysis of the Ka/Ks ratios provides evidence of functional constraint of some FAM90A genes in all species. The characterization of the FAM90A gene family contributes to a better understanding of the structural polymorphism of the human 8p23.1 region and constitutes a good example of how SDs, CNVs and rearrangements within themselves can promote the formation of new gene sequences with potential functional consequences.

Capacity-achieving input covariance for single-user multi-antenna channels

We characterize the capacity-achieving input covariance for multi-antenna channels known instantaneously at the receiver and in distribution at the transmitter. Our characterization, valid for arbitrary numbers of antennas, encompasses both the eigenvectors and the eigenvalues. The eigenvectors are found for zero-mean channels with arbitrary fading profiles and a wide range of correlation and keyhole structures. For the eigenvalues, in turn, we present necessary and sufficient conditions as well as an iterative algorithm that exhibits remarkable properties: universal applicability, robustness and rapid convergence. In addition, we identify channel structures for which an isotropic input achieves capacity.

Atomic parity nonconservation, neutron radii, and effective field theories of nuclei

Accurately calibrated effective field theories are used to compute atomic parity nonconserving (APNC) observables. Although accurately calibrated, these effective field theories predict a large spread in the neutron skin of heavy nuclei. Whereas the neutron skin is strongly correlated to numerous physical observables, in this contribution we focus on its impact on new physics through APNC observables. The addition of an isoscalar-isovector coupling constant to the effective Lagrangian generates a wide range of values for the neutron skin of heavy nuclei without compromising the success of the model in reproducing well-constrained nuclear observables. Earlier studies have suggested that the use of isotopic ratios of APNC observables may eliminate their sensitivity to atomic structure. This leaves nuclear structure uncertainties as the main impediment for identifying physics beyond the standard model. We establish that uncertainties in the neutron skin of heavy nuclei are at present too large to measure isotopic ratios to better than the 0.1% accuracy required to test the standard model. However, we argue that such uncertainties will be significantly reduced by the upcoming measurement of the neutron radius in 208^Pb at the Jefferson Laboratory.

A comparison of mean phase difference and generalized least squares for analyzing single-case data

The present study focuses on single-case data analysis and specifically on two procedures for quantifying differences between baseline and treatment measurements The first technique tested is based on generalized least squares regression analysis and is compared to a proposed non-regression technique, which allows obtaining similar information. The comparison is carried out in the context of generated data representing a variety of patterns (i.e., independent measurements, different serial dependence underlying processes, constant or phase-specific autocorrelation and data variability, different types of trend, and slope and level change). The results suggest that the two techniques perform adequately for a wide range of conditions and researchers can use both of them with certain guarantees. The regression-based procedure offers more efficient estimates, whereas the proposed non-regression procedure is more sensitive to intervention effects. Considering current and previous findings, some tentative recommendations are offered to applied researchers in order to help choosing among the plurality of single-case data analysis techniques.

Testing a new multigroup inference approach to reconstructing past environmental conditions

A new, quantitative, inference model for environmental reconstruction (transfer function), based for the first time on the simultaneous analysis of multigroup species, has been developed. Quantitative reconstructions based on palaeoecological transfer functions provide a powerful tool for addressing questions of environmental change in a wide range of environments, from oceans to mountain lakes, and over a range of timescales, from decades to millions of years. Much progress has been made in the development of inferences based on multiple proxies but usually these have been considered separately, and the different numeric reconstructions compared and reconciled post-hoc. This paper presents a new method to combine information from multiple biological groups at the reconstruction stage. The aim of the multigroup work was to test the potential of the new approach to making improved inferences of past environmental change by improving upon current reconstruction methodologies. The taxonomic groups analysed include diatoms, chironomids and chrysophyte cysts. We test the new methodology using two cold-environment training-sets, namely mountain lakes from the Pyrenees and the Alps. The use of multiple groups, as opposed to single groupings, was only found to increase the reconstruction skill slightly, as measured by the root mean square error of prediction (leave-one-out cross-validation), in the case of alkalinity, dissolved inorganic carbon and altitude (a surrogate for air-temperature), but not for pH or dissolved CO2. Reasons why the improvement was less than might have been anticipated are discussed. These can include the different life-forms, environmental responses and reaction times of the groups under study.

Mechanisms underlying cytotoxicity induced by engineered nanomaterials: a review of in vitro studies

Engineered nanomaterials are emerging functional materials with technologically interesting properties and a wide range of promising applications, such as drug delivery devices, medical imaging and diagnostics, and various other industrial products. However, concerns have been expressed about the risks of such materials and whether they can cause adverse effects. Studies of the potential hazards of nanomaterials have been widely performed using cell models and a range of in vitro approaches. In the present review, we provide a comprehensive and critical literature overview on current in vitro toxicity test methods that have been applied to determine the mechanisms underlying the cytotoxic effects induced by the nanostructures. The small size, surface charge, hydrophobicity and high adsorption capacity of nanomaterial allow for specific interactions within cell membrane and subcellular organelles, which in turn could lead to cytotoxicity through a range of different mechanisms. Finally, aggregating the given information on the relationships of nanomaterial cytotoxic responses with an understanding of its structure and physicochemical properties may promote the design of biologically safe nanostructures.

Optical trapping: a review of essential concepts

Optical tweezers are an innovative technique for the non-contact, all-optical manipulation of small material samples, which has extraordinarily expanded and evolved since its inception in the mid-80s of the last century. Nowadays, the potential of optical tweezers has been clearly proven and a wide range of applications both from the physical and biological sciences have solidly emerged, turning the early ideas and techniques into a powerful paradigm for experimentation in the micro- and nanoworld. This review aims at highlighting the fundamental concepts that are essential for a thorough understanding of optical trapping, making emphasis on both its manipulation and measurement capabilities, as well as on the vast array of important biological applications appeared in the last years.

La formulación magistral: adquisición de compètencias mediante ABP y estrategias no presenciales

[cast] La formulación magistral, una de las actividades profesionales más representativas del farmacéutico, consiste en la elaboración, de acuerdo con una prescripción médica, de un medicamento personalizado, adaptado a un paciente concreto, en un compromiso profesional de solucionar un problema de salud específico. La amplia oferta de medicamentos industriales ha reducido considerablemente esta actividad, que a pesar de todo, debe considerarse una herramienta de futuro en sintonía con la tendencia personalizadora actual de la medicina y las necesidades del paciente. Los conocimientos y competencias requeridas para dicha actividad profesional se introducen actualmente en la carrera de Farmacia mediante una asignatura optativa. En el presente trabajo se presenta el planteamiento metodológico diseñado por el Grupo de Innovación Docente de Tecnología Farmacéutica (GIDTF) y el grupo e-Galenica, ambos de la Universidad de Barcelona, para esta asignatura. Dicha metodología esta basada en el Aprendizaje Basado en Problemas (ABP) incluyendo tutorías y prácticas de campo, apoyada en estrategias no presenciales como foro de debate, recursos on-line, cuestionarios y tareas de autoevaluación a través de la plataforma Moodle del Campus Virtual de la UB. Se evalúan asimismo los resultados académicos y las respuestas de los estudiantes a las encuestas realizadas en relación al sistema de impartición de la asignatura. [eng] The pharmaceutical compounding, one of the most representative professional activities of pharmacists, involves the preparation of an individualized medicine tailored to a specific patient in a professional commitment to solve a specific health problem, according to a prescription. The wide range of industrial medicine has significantly reduced this activity, which nevertheless should be considered a tool of the future in line with the current trend of personalizing medicine and patient needs. The knowledge and competences required for this professional activity are introduced to the students of Pharmacy through an optional subject. In this paper we present the ethodological approach developed for this subject by the Teaching Innovation Group of pharmaceutical Technology (GIDTF) and e-Galenica group, both from the University of Barcelona. This methodology is based on Problem-Based Learning (PBL) including tutorials and practices in other centres, supported by out of class strategies as discussion forum, online resources, self-assessment questionnaires and work through the platform Moodle of Virtual Campus UB. The academic performance and student responses to surveys in relation to the didactic methodology are also assessed.

Com explicar un sistema CLIL: un model dinàmic newtonià

En la implementació del CLIL a l’educació superior, apart d’estudis sobre el nivell de l’estudiantat i la disponibilitat del professorat, i de l’elaboració de material educatiu interdisciplinari, el repte actual és aconseguir que s’involucrin activament en CLIL els professors de contingut d’un ventall ampli de disciplines. En aquesta comunicació es presenten les bases d’un model per un sistema CLIL, utilitzant la dinàmica newtoniana. Pot ser un model interessant i plausible en un context universitari científic i tecnològic, on fins ara el CLIL s’ha implementat només lleugerament.

Effect of long-range Coulomb interaction on shot-noise suppression in ballistic transport

We present a microscopic analysis of shot-noise suppression due to long-range Coulomb interaction in semiconductor devices under ballistic transport conditions. An ensemble Monte Carlo simulator self-consistently coupled with a Poisson solver is used for the calculations. A wide range of injection-rate densities leading to different degrees of suppression is investigated. A sharp tendency of noise suppression at increasing injection densities is found to scale with a dimensionless Debye length related to the importance of space-charge effects in the structure.