Caracterización del proceso de decisión de compra de leche en la Región de La Araucanía, Chile

Published by Asociación de Economistas Agrarios de ChileConjoint analysis, Fluid milk, Purchase behavior., Consumer/Household Economics, Marketing,

Tunable Molecular Electrodes for Bistable Polarization Screening

The polar discontinuity at any ferroelectric surface creates a depolarizing field that must be screened for the polarization to be stable. In capacitors, screening is done by the electrodes, while in bare ferroelectric surfaces it is typically accomplished by atmospheric adsorbates. Although chemisorbed species can have even better screening efficiency than conventional electrodes, they are subject to unpredictable environmental fluctuations and, moreover, dominant charged species favor one polarity over the opposite. This paper proposes a new screening concept, namely surface functionalization with resonance-hybrid molecules, which combines the predictability and bipolarity of conventional electrodes with the screening efficiency of adsorbates. Thin films of barium titanate (BaTiO) coated with resonant para-aminobenzoic acid (pABA) display increased coercivity for both signs of ferroelectric polarization irrespective of the molecular layer thickness, thanks to the ability of these molecules to swap between different electronic configurations and adapt their surface charge density to the screening needs of the ferroelectric underneath. Because electron delocalization is only in the vertical direction, unlike conventional metals, chemical electrodes allow writing localized domains of different polarity underneath the same electrode. In addition, hybrid capacitors composed of graphene/pABA/ferroelectric have been made with enhanced coercivity compared to pure graphene-electode capacitors

Control of lateral composition distribution in graded films of soluble solid systems A1-xBx by partitioned dual-beam pulsed laser deposition

Altres ajuts: AGAUR agency (project 2017SGR)Lateral compositionally-graded thin films are powerful media for the observation of phase boundaries aswell as for high-throughputmaterials exploration.We herein propose amethod to prepare epitaxial lateral compositionally-graded films using a dual-beampulsed laser deposition (PLD)method with two targets separated by a partition. Tuning the ambient pressure and the partition-substrate gap makes it possible to control of the gradient length of the deposits at the small sizes (≤ 10 mm) suitable for commercial oxide single crystal substrates. A simple Monte Carlo simulation qualitatively reproduced the characteristic features of the lateral thickness distribution. To demonstrate this method, we prepared (1-x)PbTiO-xPbZrO and (1-x)LaMnOLaSrMnO films with lateral composition gradient widths of 10 and 1 mm, respectively, with the partitioned dual PLD

Non‐destructive tomographic nanoscale imaging of ferroelectric domain walls

Extraordinary physical properties arise at polar interfaces in oxide materials, including the emergence of 2D electron gases, sheet-superconductivity, and multiferroicity. A special type of polar interface is ferroelectric domain walls, where electronic reconstruction phenomena can be driven by bound charges. Great progress has been achieved in the characterization of such domain walls and, over the last decade, their potential for next-generation nanotechnology has become clear. Established tomography techniques, however, are either destructive or offer insufficient spatial resolution, creating a pressing demand for 3D imaging compatible with future fabrication processes. Here, non-destructive tomographic imaging of ferroelectric domain walls is demonstrated using secondary electrons. Utilizing conventional scanning electron microscopy (SEM), the position, orientation, and charge state of hidden domain walls are reconstructed at distances up to several hundreds of nanometers away from the surface. A mathematical model is derived that links the SEM intensity variations at the surface to the local domain wall properties, enabling non-destructive tomography with good noise tolerance on the timescale of seconds. The SEM-based approach facilitates high-throughput screening of materials with functional domain walls and domain-wall-based devices, which is essential for monitoring during the production of device architectures and quality control in real-time

A ferroelectric memristor

Memristors are continuously tunable resistors that emulate synapses. Conceptualized in the 1970s, they traditionally operate by voltage-induced displacements of matter, but the mechanism remains controversial. Purely electronic memristors have recently emerged based on well-established physical phenomena with albeit modest resistance changes. Here we demonstrate that voltage-controlled domain configurations in ferroelectric tunnel barriers yield memristive behaviour with resistance variations exceeding two orders of magnitude and a 10 ns operation speed. Using models of ferroelectric-domain nucleation and growth we explain the quasi-continuous resistance variations and derive a simple analytical expression for the memristive effect. Our results suggest new opportunities for ferroelectrics as the hardware basis of future neuromorphic computational architectures

Circulating omentin concentration increases after weight loss

Omentin-1 is a novel adipokine expressed in visceral adipose tissue and negatively associated with insulin resistance and obesity. We aimed to study the effects of weight loss-induced improved insulin sensitivity on circulating omentin concentrations. METHODS: Circulating omentin-1 (ELISA) concentration in association with metabolic variables was measured in 35 obese subjects (18 men, 17 women) before and after hypocaloric weight loss. RESULTS: Baseline circulating omentin-1 concentrations correlated negatively with BMI (r = -0.58, p < 0.001), body weight (r = -0.35, p = 0.045), fat mass (r = -0.67, p < 0.001), circulating leptin (r = -0.7, p < 0.001) and fasting insulin (r = -0.37, p = 0.03). Circulating omentin-1 concentration increased significantly after weight loss (from 44.9 +/- 9.02 to 53.41 +/- 8.8 ng/ml, p < 0.001). This increase in circulating omentin after weight loss was associated with improved insulin sensitivity (negatively associated with HOMA value and fasting insulin, r = -0.42, p = 0.02 and r = -0.45, p = 0.01, respectively) and decreased BMI (r = -0.54, p = 0.001). CONCLUSION: As previously described with adiponectin, circulating omentin-1 concentrations increase after weight loss-induced improvement of insulin sensitivity

Uso de insecticidas y fungicidas en agroecosistemas de papa en la Region de Cusco

Esta investigación permitió registrar y conocer las fortalezas y debilidades de los agricultores en el uso técnico de insecticidas y fungicidas, para el control de plagas y enfermedades y las implicancias ambientales que esta tecnología genera en agroecosistemas andinos de Cusco. conocer las debilidades de frecuencia de aplicación, dosis, principios activos y su relación con la contaminación ambiental, servirá como base de datos, para que las instituciones de competencia incorporen esta debilidad en la asistencia técnica y mejoren las capacidades sobre el uso adecuado de esta tecnología.Se realizaron encuestas a 71 agricultores en siete comunidades ubicadas de 2670 a 3992 msnm. Los datos colectados permitieron determinar el valor estimado de impacto ambiental con “A Method to Measure the Environmental Impact of Pesticides”. Se reportaron siete plagas y dos enfermedades principales utilizando Para su control, usan insecticidas con cinco principios activos de fosforado, tres de carbamato, siete de piretroide y cuatro de misceláneos; en fungicida usan ocho principios activos compuestos y siete de un principio activo. Mostrando un conocimiento de nivel medio a bajo en el uso técnico de insecticidas y fungicidas. Para 20 hectáreas, el valor de impacto ambiental estimado para insecticidas fue de 83.977 ud en la zona baja, 198.434 ud en la zona media, y 83.217 ud en la zona alta. Para fungicidas fue de 390.376 ud en la zona baja, 261.865 ud en la zona media y 160. 560 ud en la zona alta. Estos valores representan de nivel medio a alto en impacto ambiental negativo

Study of caveolin-1 gene expression in whole adipose tissue and its subfractions and during differentiation of human adipocytes

Caveolins are 21-24 kDa integral membrane proteins that serve as scaffolds to recruit numerous signaling molecules. Specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triglycerides are synthesized at the site of fatty acid entry in one of these caveolae classes. OBJECTIVE AND METHODS: We studied the expression of caveolin-1 (CAV-1) gene in association with metabolic variables in 90 visceral and 55 subcutaneous adipose tissue samples from subjects with a wide range of fat mass, in the stromovascular fraction (SVC) and isolated adipocytes, and during differentiation of human adipocytes. RESULTS: CAV-1 gene expression was significantly decreased in visceral adipose tissue (v-CAV-1) of obese subjects. v-CAV-1 was positively associated with several lipogenic genes such as acetyl-coA carboxylase (ACACA, r = 0.34, p = 0.004) and spot-14 (r = 0.33, p = 0.004). In non-obese subjects v-CAV-1 also correlated with fatty acid synthase (FAS, r = 0.60, p < 0.0001). Subcutaneous (sc) adipose tissue (sc-CAV-1) gene expression was not associated with these lipogenic factors when obese and non-obese subjects were studied together. In obese subjects, however, sc-CAV-1 was associated with fatty acid synthase (FAS, r = 0.36, p = 0.02), sterol regulatory element binding protein-1c (SREBP-1c (r = 0.58, p < 0.0001), ACACA (r = 0.33, p = 0.03), spot-14 (r = 0.36, p = 0.02), PPAR-gamma co-activator-1 (PGC-1, r = 0.88, n = 19). In these obese subjects, sc-CAV-1 was also associated with fasting triglycerides (r = -0.50, p < 0.0001).CAV-1 expression in mature adipocytes was significantly higher than in stromal vascular cells. CAV-1 gene expression in adipocytes from subcutaneous adipose tissue (but not in adipocytes from visceral adipose tissue) was significatively associated with fasting triglycerides. CAV-1 gene expression did not change significantly during differentiation of human preadipocytes from lean or obese subjects despite significant increase of FAS gene expression. CONCLUSION: Decreased CAV-1 gene expression was simultaneously linked to increased triglycerides and decreased lipogenic gene expression among obese subjects, paralleling the observations of hypertriglyceridemia in CAV-1 knockout mice. However, the regulation of CAV-1 gene expression seems independent of the adipogenic program

Heat flux distribution of Antarctica unveiled

Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent-wide heat flux maps have only been derived from low-resolution satellite magnetic and seismological data. We present a high resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small-scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high-resolution heat-flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice-sheet dynamics and sea-level chang

Impact of the implementation of electronic guidelines for cardiovascular prevention in primary care: study protocol

Background The electronic medical records software of the Catalan Institute of Health has recently incorporated an electronic version of clinical practice guidelines (e-CPGs). This study aims to assess the impact of the implementation of e-CPGs on the diagnosis, treatment, control and management of hypercholesterolaemia, diabetes mellitus type 2 and hypertension.Methods Eligible study participants are those aged 35–74 years assigned to family practitioners (FPs) of the Catalan Institute of Health. Routinely collected data from electronic primary care registries covering 80% of the Catalan population will be analysed using two approaches: (1) a cross-sectional study to describe the characteristics of the sample before e-CPG implementation; (2) a controlled before-and-after study with 1-year follow-up to ascertain the effect of e-CPG implementation. Patients of FPs who regularly use the e-CPGs will constitute the intervention group; the control group will comprise patients assigned to FPs not regularly using the e-CPG. The outcomes are: (1) suspected and confirmed diagnoses, (2) control of clinical variables, (3) requests for tests and (4) proportions of patients with adequate drug prescriptions.Results This protocol should represent a reproducible process to assess the impact of the implementation of e-CPGs. We anticipate reporting results in late 2013.Conclusion This project will assess the effectiveness of e-CPGs to improve clinical decisions and healthcare procedures in the three disorders analysed. The results will shed light on the use of evidence-based medicine to improve clinical practice of FPs