Large Polarization and Susceptibilities in Artificial Morphotropic Phase Boundary PbZr1−xTixO3 Superlattices

The ability to produce atomically precise, artificial oxide heterostructures allows for the possibility of producing exotic phases and enhanced susceptibilities not found in parent materials. Typical ferroelectric materials either exhibit large saturation polarization away from a phase boundary or large dielectric susceptibility near a phase boundary. Both large ferroelectric polarization and dielectric permittivity are attained wherein fully epitaxial (PbZr0.8Ti0.2O3)n/(PbZr0.4Ti0.6O3)2n (n = 2, 4, 6, 8, 16 unit cells) superlattices are produced such that the overall film chemistry is at the morphotropic phase boundary, but constitutive layers are not. Long- (n ≥ 6) and short-period (n = 2) superlattices reveal large ferroelectric saturation polarization (Ps = 64 µC cm−2) and small dielectric permittivity (εr ≈ 400 at 10 kHz). Intermediate-period (n = 4) superlattices, however, exhibit both large ferroelectric saturation polarization (Ps = 64 µC cm−2) and dielectric permittivity (εr = 776 at 10 kHz). First-order reversal curve analysis reveals the presence of switching distributions for each parent layer and a third, interfacial layer wherein superlattice periodicity modulates the volume fraction of each switching distribution and thus the overall material response. This reveals that deterministic creation of artificial superlattices is an effective pathway for designing materials with enhanced responses to applied bias

Stochastic pump of interacting particles

We consider the overdamped motion of Brownian particles, interacting via particle exclusion, in an external potential that varies with time and space. We show that periodic potentials that maintain specific position-dependent phase relations generate time-averaged directed current of particles. We obtain analytic results for a lattice version of the model using a recently developed perturbative approach. Many interesting features like particle-hole symmetry, current reversal with changing density, and system-size dependence of current are obtained. We propose possible experiments to test our predictions.Comment: 4 pages, 2 figure

Swine production simulation model: LIFE SIM

Supported by the CGIAR Systemwide Livestock ProgrammeNon-ruminant animals are essential in many resource-poor production systems, particularly in Asia. The feeding strategies are as varied as the different agro ecosystems, thus increasing the challenge faced by researchers and extension agents in the search for appropriate solutions to feeding limitations. Systems analysis provides a unique opportunity to translate existing knowledge into process-based models that can be used to assess year-round feeding strategies at the farm level. Although livestock models have been developed to address similar situations for ruminant animals, swine are seldom included. The present work describes a swine model that analyzes the bioeconomic response to feeding strategies in different production systems. This swine model has been incorporated into the software Livestock Feeding Strategies Simulation Model (LIFE-SIM) complementing the existing models for ruminant species: Dairy, Beef, Goat, and Buffalo (León-Velarde et al., 2006) The model simulates a confined group of animals (at least two females or males) with a weight ranging from 15 to 120 kg, under either an ad libitum or controlled feeding regime with a feed value characterized in terms of dry matter (%), metabolizable energy (ME/kg), crude fiber (%), lysine (%), methionine + cystine (%), threonine (%), and tryptophan (%). The model can store a number of different rations and their prices allowing a comparison during a defined fattening period. Weight gain and the bioeconomic performance of each ration can then be estimated and analyzed

Effect of synthetic clay and biochar addition on dissipation and enantioselectivity of tebuconazole and metalaxyl in an agricultural soil: Laboratory and field experiments

10 páginas.-- 4 figuras.-- 3 tablas.-- referencias.-- Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.agee.2016.05.017Laboratory and field experiments were conducted to assess how the addition of oleate-modified hydrotalcite (clay) and biochar (BC) to an agricultural soil affected the sorption, leaching, persistence, and enantiomeric composition of soil residues of two chiral fungicides, tebuconazole and metalaxyl. Laboratory experiments showed that the sorption of both fungicides ranked as follows: unamended soil < BC-amended soil < clay-amended soil. The addition of clay at a rate of 1% increased metalaxyl soil sorption coefficient (Kd) from 0.34 to 3.14 L kg−1 and that of tebuconazole from 2.4 to 47.4 L kg−1. In our experimental set-up, field plots were either unamended or amended with clay (2 t ha−1) or BC (4 t ha−1), and subsequently treated with a mixture of tebuconazole and metalaxyl at 3 and 6 kg ha−1, respectively. The leaching, persistence, and enantiomer composition of fungicides residues were monitored by sampling at different soil depths (0–5, 5–10, 10–20 cm) for 98 days. No significant changes in the scarce mobility and long persistence of tebuconazole upon amending the soil with clay or BC were observed. In contrast, sorption to clay and BC particles reduced the leaching and degradation of metalaxyl and the clay increased its persistence in the topsoil compared to the unamended soil. The enantioselective analysis of tebuconazole and metalaxyl soil residues indicated that tebuconazole remained mostly racemic along the experiment, whereas for metalaxyl the concentration of S-enantiomer was greater than the concentration of R-enantiomer, more so at longer experimental times and deeper horizons. Nevertheless, for the top 0–5 cm soil layer metalaxyl remained more racemic in clay- and BC-amended soil than in unamended soil. Our results show that addition of amendments with high sorptive capacities can be beneficial in reducing leaching and degradation losses of chiral pesticide enantiomers from the topsoil, and that sorption by the amendments can influence the final enantiomeric composition of pesticide residues.This work was financed by the Spanish Ministry of Economy and Competitiveness (MINECO Projects AGL2011-23779, AGL2013-48446-C3-1-R and AGL2014-51897-R) and Junta de Andalucía (JA Research Group AGR-264), with FEDER-FSE funds. R. López-Cabeza thanks MINECO for a pre-doctoral fellowship linked to the Project AGL2011-23779 (Grant BES-2012-059945). The authors also thank P. Franco (Chiral Technologies Europe) and I. Girón (IRNAS) for their technical assistancePeer reviewe

Sustitución ureteral bilateral con asa ileal

Indexación: Web of Science; ScieloUreteral replacement by a loop of defunctionalized ileum was described more than 2 centuries ago and continues to be a therapeutic option at present. This series describes the technique of bilateral ureteral replacement with ileum. Aim: To report 4 cases of bilateral ileal ureteral replacement performed at our institution, its indications, the surgical technique, complications, and a review of the literature. Material and Method: We report 4 cases of extensive bilateral ureteral injury of different etiologies, whose treatment with curative intent was to replace the damaged ureter with a isoperistaltic small bowel segment. Results: The surgical technique used was standard in all cases. There were no intraoperative complications and only one patient had hyperchloremic acidosis. No patient has shown loss of renal function in the long-term follow up. Conclusion: Is an effective therapeutic, safe and reproducible technique to replacement of major bilateral ureteral injuries, independent of the original cause.La sustitución ureteral por un asa de íleon desfuncionalizada fue descrita hace más de 2 siglos y continúa siendo una alternativa terapéutica en la actualidad. Esta serie describe la técnica de sustitución ureteral bilateral con íleon. Objetivo: Presentar 4 casos de sustitución ureteral ileal bilateral realizados en nuestro centro, indicaciones de la técnica quirúrgica, complicaciones y revisión de la literatura. Material y Método: Presentamos 4 casos de lesión ureteral bilateral extensa, de etiologías diferentes, cuyo tratamiento con intención curativa fue la sustitución de la lesión ureteral por un segmento intestinal isoperis-táltico. Resultados: La técnica quirúrgica empleada fue estándar en todos los casos. No hubo complicaciones intraoperatorias, y sólo una paciente presentó descompensación metabólica por acidosis hiperclorémica. En ningún paciente se ha demostrado pérdida en la función renal. Conclusión: El segmento intestinal de íleon desfuncionalizado es una alternativa terapéutica eficaz, segura y reproducible, para el reemplazo de importantes lesiones ureterales bilaterales, independiente de la causa original.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-40262012000500012&nrm=is

Search for Intermediate Mass Magnetic Monopoles and Nuclearites with the SLIM experiment

SLIM is a large area experiment (440 m2) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (107-1013 GeV/c2) and nuclearites in the cosmic radiation using stacks of CR39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10-15 cm-2 s-1 sr-1. We present the results of the calibration of CR39 and Makrofol and the analysis of a first sample of the exposed detector.Comment: Presented at the 22nd ICNTS, Barcelona 200

Search for strange quark matter and Q-balls with the SLIM experiment

We report on the search for Strange Quark Matter (SQM) and charged Q-balls with the SLIM experiment at the Chacaltaya High Altitude Laboratory (5230 m a.s.l.) from 2001 to 2005. The SLIM experiment was a 427 m$^{2}$ array of Nuclear Track Detectors (NTDs) arranged in modules of $24 \times 24$ cm$^{2}$ area. SLIM NTDs were exposed to the cosmic radiation for 4.22 years after which they were brought back to the Bologna Laboratory where they were etched and analyzed. We estimate the properties and energy losses in matter of nuclearites (large SQM nuggets), strangelets (small charged SQM nuggets) and Q-balls; and discuss their detection with the SLIM experiment. The flux upper limits in the CR of such downgoing particles are at the level of $1.3 10^{-15}$/cm$^{2}$/s/sr (90% CL).Comment: 4 pages, 7 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200

Ahorro energético en riego por aspersión. Pruebas de nuevos aspersores en banco automático con viento

El consumo energético en regadío es directamente proporcional a los valores objetivos de presión de una red colectiva de riego presurizada. El sistema de riego en parcela que más condiciona esta presión objetivo es el riego por aspersión. En este trabajo se ha analizado el comportamiento de los aspersores más utilizados en España en condiciones normales de funcionamiento frente a condiciones de presiones más bajas. Para ello se utilizó un banco de ensayo automático con viento y otro en condiciones confinadas sin viento. Se analizaron los aspersores en múltiples condiciones de trabajo, priorizando en el estudio la variable presión. Para ello se contempló un rango de presiones de 1,5 bar a 3.5 bar y con dos regímenes de viento: sin viento y con viento moderado. Como resultados del estudio se ofrece un análisis global de los datos obtenidos, que justifican la posibilidad de reducir la presión en riego por aspersión Además, se profundiza en resultados concretos para la reducción de la presión en el marco de riego de doce por quince metros