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

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

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

Effectiveness of Thrombectomy in Stroke According to Baseline Prognostic Factors: Inverse Probability of Treatment Weighting Analysis of a Population-Based Registry

Background and Purpose In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors. Methods Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score 85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score 3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups' criteria). Results Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3). Conclusions Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors

Maximum in the Middle: Nonlinear Response of Microbial Plankton to Ultraviolet Radiation and Phosphorus

The responses of heterotrophic microbial food webs (HMFW) to the joint action of abiotic stressors related to global change have been studied in an oligotrophic high-mountain lake. A 2×5 factorial design field experiment performed with large mesocosms for >2 months was used to quantify the dynamics of the entire HMFW (bacteria, heterotrophic nanoflagellates, ciliates, and viruses) after an experimental P-enrichment gradient which approximated or surpassed current atmospheric P pulses in the presence vs. absence of ultraviolet radiation. HMFW underwent a mid-term (<20 days) acute development following a noticeable unimodal response to P enrichment, which peaked at intermediate P-enrichment levels and, unexpectedly, was more accentuated under ultraviolet radiation. However, after depletion of dissolved inorganic P, the HMFW collapsed and was outcompeted by a low-diversity autotrophic compartment, which constrained the development of HMFW and caused a significant loss of functional biodiversity. The dynamics and relationships among variables, and the response patterns found, suggest the importance of biotic interactions (predation/parasitism and competition) in restricting HMFW development, in contrast to the role of abiotic factors as main drivers of autotrophic compartment. The response of HMFW may contribute to ecosystem resilience by favoring the maintenance of the peculiar paths of energy and nutrient-mobilization in these pristine ecosystems, which are vulnerable to threats by the joint action of abiotic stressors related to global change.This research was supported by Junta de Andalucía (Excelencia P07-CVI-02598 to PC, and P09-RNM-5376 to JMMS), the Spanish Ministries of Medio Ambiente, Rural y Marino (PN2009/067 to PC) and Ciencia e Innovación (GLC2008-01127/BOS and CGL2011-23681 to PC), the ERC Advanced Grant project number 250254 “MINOS” (to GB), and two Spanish government grants (to JADM and FJB)