Modeling the unsaturated flow associated with a border irrigation event on an alfalfa plot

HYDRUS-1D, un modelo unidimensional de movimiento de agua y transporte de solutos, se utilizó en el contexto de un evento de riego por fajas en una parcela de alfalfa ubicada en el polígono de riego de "La Violada" (España) a fin de analizar la interacción suelo-planta-agua en la zona no saturada del suelo. El evento de riego se monitoreó para derivar información adecuada para establecer el modelo numérico de la zona de estudio así como para evaluarlo. El protocolo de modelización, de carácter determinista-estocástico, incluyó calibración, evaluación y análisis de sensibilidad. Tanto las predicciones del modelo como los datos de campo revelaron que el contenido de humedad del suelo fue alto durante el período de monitoreo; el modelo inclusive predijo un decrecimiento pequeño de la evapotranspiración inducido por el humedecimiento significativo del suelo, y la contribución importante al balance de agua del ascenso capilar como consecuencia del ascenso del nivel freático causado por el riego previo en la parcela adyacente. Los resultados de la presente modelización sugieren la necesidad de mejorar la definición del modelo numérico de la zona no saturada y de las respectivas condiciones de contorno. Para ello, el estudio reveló la necesidad de (i) generar mejores valores experimentales para algunos de los parámetros más importantes del modelo; y (ii) obtener series temporales más precisas para las condiciones de frontera superiores e inferiores.HYDRUS-1D, a one dimensional water movement and solute transport model, was applied to analyze a border irrigation event in an alfalfa plot located in the irrigation district of "La Violada" (Spain). The research encompassed monitoring of the irrigation event, the setting-up of the numerical model, model calibration and evaluation, and sensitivity analysis of the van Genuchten-Mualem parameters. Both the model predictions and field measurements clearly indicated that the soil water content was high during and following the irrigation event. The model even predicted a small evapotranspiration decrease induced by water logging and a significant contribution of capillary rise subsequently the water table rise in the adjacent plot caused by an irrigation event prior to the monitored event in the study plot. The research revealed the need for (i) the improvement of the schematization of the soil profile and the better experimental definition of key model parameters; and (ii) the derivation of more accurate data series for respectively the upper and lower boundary conditions.HYDRUS-1Driego por fajassimulaciones Monte Carlozona vadosaBorder irrigationMonte Carlo simulationsvadose zonePublishe

MOCVD growth of Bi2Te3-Sb2Te3 layers : Effect of growth parameters on the electrical and thermoelectrical properties

The growth of (Bi1-xSbx)2Te3 thin films by metal-organic chemical vapour deposition (MOCVD) using trimethylbismuth, triethylantimony and diethyltellurium as bismuth, antimony and tellurium sources respectively is investigated on pyrex substrates. The electrical and thermoelectrical properties of this material are also measured over the growth temperature range 360-470°C. The studies are also made on the effect of VI/V ratio on these properties in the variation range 2-9. Polycrystalline structure is confirmed by X-ray diffraction, and it is observed that the intensity of the preferred orientation is higher at 450°C. The measurement of Seebeck coefficient shows that all samples have p-type conduction. The best value of this parameter is obtained for high growth temperature (240µV/K). The good result obtained for (Bi1-xSbx)2Te3 thin films revealed the great potential of MOCVD method which is an industrial technique to produce good materials for device applications (sensors and thermopiles).The growth of (Bi1-xSbx)2Te3 thin films by metal-organic chemical vapour deposition (MOCVD) using trimethylbismuth, triethylantimony and diethyltellurium as bismuth, antimony and tellurium sources respectively is investigated on pyrex substrates. The electrical and thermoelectrical properties of this material are also measured over the growth temperature range 360-470°C. The studies are also made on the effect of VI/V ratio on these properties in the variation range 2-9. Polycrystalline structure is confirmed by X-ray diffraction, and it is observed that the intensity of the preferred orientation is higher at 450°C. The measurement of Seebeck coefficient shows that all samples have p-type conduction. The best value of this parameter is obtained for high growth temperature (240µV/K). The good result obtained for (Bi1-xSbx)2Te3 thin films revealed the great potential of MOCVD method which is an industrial technique to produce good materials for device applications (sensors and thermopiles)

Etude théorique du transport électronique par la simulation Monte Carlo dans le quaternaire In0.863Ga0.137As0.3P0.7

Afin de simuler le comportement d'un laser à semi-conducteur, nous devons disposer de modèles mathématiques décrivant de façons aussiprécise que possible les propriétés physiques des matériaux considérés.Ces dernières années plusieurs recherches ont été consacrées aux lasers de type InGaAsP-InP. Plusieurs paramètres physiques sont connus avec une précision plus ou moins satisfaisante. Nous avons tenté, de reproduire au mieux l'ensemble des mesures rapportées dans la littérature et d’étudier le phénomène de transport dans les semiconducteurs quaternaire. Pour cela nous avons effectué des simulations microscopiques, basées sur la méthode Monte Carlo. Nous avonsappliqué cette méthode au cas du quaternaire "In0.863Ga0.137As0.3P0.7-InP", considérant une bande de conduction à trois vallées (Γ, L, X), isotropes et quasi paraboliques. Les interactions prises en compte sont dues aux phonons optiques polaires, optiques non polaires, acoustiques, intervallées, piézoélectriques ainsi que les interactions d'alliage et sur impuretés ionisées. Dans un premier temps, nous présentons l’ensemble des résultats obtenus par la simulation de Monte Carlo dans l'In0.863Ga0.137As0.3P0.7 en régime stationnaire. Nous considérons ensuite les effets liés à l’application d’un champ électrique variant très rapidement en fonction du temps. Nous étudions en particulier les phénomènes non stationnaires qui font leur apparition dans le matériau quaternaire.Mots-clés : simulation de Monte Carlo, In0.863Ga0.137As0.3P0.7, interaction, composants électroniques

End-of-fabrication CMOS process monitor

A set of test 'modules' for verifying the quality of a complementary metal oxide semiconductor (CMOS) process at the end of the wafer fabrication is documented. By electrical testing of specific structures, over thirty parameters are collected characterizing interconnects, dielectrics, contacts, transistors, and inverters. Each test module contains a specification of its purpose, the layout of the test structure, the test procedures, the data reduction algorithms, and exemplary results obtained from 3-, 2-, or 1.6-micrometer CMOS/bulk processes. The document is intended to establish standard process qualification procedures for Application Specific Integrated Circuits (ASIC's)

Product assurance technology for custom LSI/VLSI electronics

The technology for obtaining custom integrated circuits from CMOS-bulk silicon foundries using a universal set of layout rules is presented. The technical efforts were guided by the requirement to develop a 3 micron CMOS test chip for the Combined Release and Radiation Effects Satellite (CRRES). This chip contains both analog and digital circuits. The development employed all the elements required to obtain custom circuits from silicon foundries, including circuit design, foundry interfacing, circuit test, and circuit qualification

Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis

Challenges and Opportunities: What Can We Learn from Patients Living with Chronic Musculoskeletal Conditions, Health Professionals and Carers about the Concept of Health Literacy Using Qualitative Methods of Inquiry?

The field of health literacy continues to evolve and concern public health researchers and yet remains a largely overlooked concept elsewhere in the healthcare system. We conducted focus group discussions in England UK, about the concept of health literacy with older patients with chronic musculoskeletal conditions (mean age = 73.4 years), carers and health professionals. Our research posed methodological, intellectual and practical challenges. Gaps in conceptualisation and expectations were revealed, reiterating deficiencies in predominant models for understanding health literacy and methodological shortcomings of using focus groups in qualitative research for this topic. Building on this unique insight into what the concept of health literacy meant to participants, we present analysis of our findings on factors perceived to foster and inhibit health literacy and on the issue of responsibility in health literacy. Patients saw health literacy as a result of an inconsistent interactive process and the implications as wide ranging; healthcare professionals had more heterogeneous views. All focus group discussants agreed that health literacy most benefited from good inter-personal communication and partnership. By proposing a needs-based approach to health literacy we offer an alternative way of conceptualising health literacy to help improve the health of older people with chronic conditions

The association of health literacy with adherence in older 2 adults, and its role in interventions: a systematic meta-review

Background: Low health literacy is a common problem among older adults. It is often suggested to be associated with poor adherence. This suggested association implies a need for effective adherence interventions in low health literate people. However, previous reviews show mixed results on the association between low health literacy and poor adherence. A systematic meta-review of systematic reviews was conducted to study the association between health literacy and adherence in adults above the age of 50. Evidence for the effectiveness of adherence interventions among adults in this older age group with low health literacy was also explored. Methods: Eight electronic databases (MEDLINE, ERIC, EMBASE, PsycINFO, CINAHL, DARE, the Cochrane Library, and Web of Knowledge) were searched using a variety of keywords regarding health literacy and adherence. Additionally, references of identified articles were checked. Systematic reviews were included if they assessed the association between health literacy and adherence or evaluated the effectiveness of interventions to improve adherence in adults with low health literacy. The AMSTAR tool was used to assess the quality of the included reviews. The selection procedure, data-extraction, and quality assessment were performed by two independent reviewers. Seventeen reviews were selected for inclusion. Results: Reviews varied widely in quality. Both reviews of high and low quality found only weak or mixed associations between health literacy and adherence among older adults. Reviews report on seven studies that assess the effectiveness of adherence interventions among low health literate older adults. The results suggest that some adherence interventions are effective for this group. The interventions described in the reviews focused mainly on education and on lowering the health literacy demands of adherence instructions. No conclusions could be drawn about which type of intervention could be most beneficial for this population. Conclusions: Evidence on the association between health literacy and adherence in older adults is relatively weak. Adherence interventions are potentially effective for the vulnerable population of older adults with low levels of health literacy, but the evidence on this topic is limited. Further research is needed on the association between health literacy and general health behavior, and on the effectiveness of interventions

Polymorphisms in the α4 Integrin of Neotropical Primates: Insights for Binding of Natural Ligands and HIV-1 gp120 to the Human α4β7

The α4 integrin subunit associates with β7 and β1 and plays important roles in immune function and cell trafficking. The gut-homing receptor α4β7 has been recently described as a new receptor for HIV. Here, we describe polymorphisms of ITGA4 gene in New World primates (NWP), and tested their impact on the binding to monoclonal antibodies, natural ligands (MAdCAM and VCAM), and several gp120 HIV-1 envelope proteins. Genomic DNA of NWP specimens comprising all genera of the group had their exons 5 and 6 (encoding the region of binding to the ligands studied) analyzed. The polymorphisms found were introduced into an ITGA4 cDNA clone encoding the human α4 subunit. Mutant α4 proteins were co-expressed with β7 and were tested for binding of mAbs, MAdCAM, VCAM and gp120 of HIV-1, which was compared to the wild-type (human) α4. Mutant α4 proteins harboring the K201E/I/N substitution had reduced binding of all ligands tested, including HIV-1 gp120 envelopes. The mAbs found with reduced biding included one from which a clinically-approved drug for the treatment of neurological disorders has been derived. α4 polymorphisms in other primate species may influence outcomes in the development and treatment of infectious and autoimmune diseases in humans and in non-human primates

Evolution of the Antiretroviral Restriction Factor TRIMCyp in Old World Primates

The retroviral restriction factor TRIMCyp, which is a fusion protein derived from the TRIM5 gene, blocks replication at a post-entry step. Among Old World primates, TRIMCyp has been found in four species of Asian macaques, but not in African monkeys. To further define the evolutionary origin of Old World TRIMCyp, we examined two species of baboons (genus Papio) and three additional macaque species, including M. sylvanus, which is the only macaque species found outside Asia, and represents the earliest diverging branch of the macaque lineage. None of four P. cynocephalus anubis, one P. hamadryas, and 36 M. sylvanus had either TRIMCyp mRNA or the genetic features required for its expression. M. sylvanus genomic sequences indicated that the lack of TRIMCyp in this species was not due to genetic homogeneity among specimens studied and revealed the existence of four TRIM5α alleles, all distinct from M. mulatta and Papio counterparts. Together with existing data on macaque evolution, our findings indicate that TRIMCyp evolved in the ancestors of Asian macaques approximately 5–6 million years before present (ybp), likely as a result of a retroviral threat. TRIMCyp then became fixed in the M. nemestrina lineage after it diverged from M. nigra, approximately 2 million ybp. The macaque lineage is unique among primates studied so far due to the presence and diversity of both TRIM5 and TRIMCyp restriction factors. Studies of these antiviral proteins may provide valuable information about natural antiviral mechanisms, and give further insight into the factors that shaped the evolution of macaque species