1,875 research outputs found
Lp-solutions of the Navier-Stokes equation with fractional Brownian noise
We study the Navier-Stokes equations on a smooth bounded domain D ⊂ Rd (d = 2 or 3), under the effect of an additive fractional Brownian noise. We show local existence and uniqueness of a mild Lp-solution for p > d.34539553FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2017/17670-0; 2015/07278-
Multiple bromotryptophan and y-carboxyglutamate residues in a Conus peptide
Journal ArticleA novel peptide was purified from Conus textile venom which caused hyperactivity in mice. The 31-amino acid peptide has six residues with unusual post-translational modifications: four y-carboxyglutamates and two brominated tryptophan residues. This peptide, which we have designated the dibromorunning peptide, is the first known gene product with multiple bromotryptophan residues. We discuss the apparent non-random association of y-carboxyglutamate and bromotryptophan in Conus peptides
Single amino acid substitutions in ĸ-conotoxin PVIIA disrupt interaction with the Shaker K+ channel
Journal Articleĸ-Conotoxin PVIIA (ĸ-PVIIA), a 27-amino acid peptide with three disulfide cross-links, isolated from the venom of Conus purpurascens, is the first conopeptide shown to inhibit the Shaker K1 channel (Terlau, H., Shon, K., Grilley, M., Stocker, M., Stühmer, W., and Olivera, B. M. (1996) Nature 381, 148-151). Recently, two groups independently determined the solution structure for ĸ-PVIIA using NMR; although the structures reported were similar, two mutually exclusive models for the interaction of the peptide with the Shaker channel were proposed
A Model for Evaluating B2C eCommerce Websites: Application in the CD eRetailing Industry in Brazil
The scope of this research is to develop and test a model for evaluating B2C e-commerce websites quantitatively. Consequently, this study seeks to investigate the relationship between the website interface of B2C e-commerce and virtual customer behavior, emphasizing the purchasing attitude and intention. The objective of this paper is, therefore, to research which features of a virtual store effectively influence the user purchasing process via the Internet. In order to achieve this aim, the Technology Acceptance Model (TAM) was adapted for pertinent theoretical references about consumer behavior on the web. The model developed was then tested and validated through a Structural Equation Modeling (SEM) approach. An empirical analysis of the CD e-retailing industry in Brazil was then conducted, as this is one of the most important areas of the B2C e-commerce realm. The study concludes that, for the electronic commerce of CDs, ease of use, trust, pleasure and attractiveness as perceived by visitors to CD e-retailing websites are key issues for understanding customer attitude and purchasing intention. Lastly, recommendations associated with the conclusions of this research are made, and further research options are proposed
Is Helping Really Helping? Health-Related Quality of Life after TBI Predicting Caregiver Depression Longitudinally in Latin America
Objective: Studies have shown that functional and psychosocial sequelae of traumatic brain injury (TBI) predict emotional well-being of caregivers (Harris, 2000). Previous research examining the mental health of caregivers and the health-related quality of life (HRQoL) of people with TBI have primarily been in the US (Sander, 2012). Very little research has been conducted to uncover the unique relationships between HRQoL of people with TBI and caregiver mental health longitudinally, or in low-middle income Latin American countries. The aim of this study was to evaluate how HRQoL after TBI predict caregiver depression longitudinally in two countries and three data collection sites in Latin America.
Design: Multi-site, multinational longitudinal study.
Setting: Three hospitals in Neiva and Cali, Colombia, and Mexico City, Mexico (before hospital discharge), as well as in the homes of individuals with TBI and caregivers in these regions (before discharge, at 2 and 4 months after discharge).
Participants: A sample of 109 TBI caregiver-patient dyads (n = 218) was included in the study.
Main Outcome Measure(s): Caregiver depression (Patient Health Questionnaire-9) and HRQoL in the person with TBI (Short Form-36).
Results: Three multiple regressions were conducted to examine which aspects of patient HRQoL at baseline predicted caregiver depression at baseline, 2 months, and 4 months post-discharge. Eight aspects of patient HRQoL were simultaneously entered into each model as predictors: physical functioning, role limitations (physical and emotional), vitality, mental health, social functioning, pain, and general health. At baseline, the overall model significantly predicted caregiver depression, F(8, 105) = 2.62, p = .012, R 2 = .18. Patient mental health was the only significant unique predictor of caregiver depression at baseline, p = .021, β = -.34. The overall model predicting 2-month caregiver depression was significant, F(8, 101) = 3.21, p = .003, R 2 = .22. Only mental health, p = .016, β = -.36, was a significant unique predictor. The overall model predicting 4-month caregiver depression was significant, F(8, 98) = 2.70, p = .010, R 2 = .19, and no factors uniquely predicted caregiver depression, all ps\u3e.05.
Conclusions: Results suggest that TBI patient HRQoL can predict caregiver depression among Latin American caregivers before and during the first 4 months after hospital discharge. Across all three time points (baseline, 2 months, and 4 months), caregiver depression was significantly predicted by patient HRQoL. At baseline, patient mental health was the only domain that uniquely predicted caregiver depression. At 2 months, only physical role limitations uniquely predicted caregiver depression, and no unique predictors were detected at 4 months. These findings suggest that within the cultural framework in Latin America, there is a strong relationship between functional and psychological impairments after TBI and depression outcomes in Latin American caregivers. The results highlight the importance of uncovering these relational distinctions and may infer early detection of mental health needs and psychological intervention considerations for Latin American caregivers.https://scholarscompass.vcu.edu/gradposters/1052/thumbnail.jp
Synthesis of hierarchically structured Y2O3:Eu3*@ Ag nanocomposites with plasmon enhanced luminesencence via ultrasonic spray pyrolysis
Y2O3:Eu3+@Ag nanocomposites have been successfully synthesized by ultrasonic spray pyrolysis (USP) and examined to reveal effects of surface plasmon resonance, associated to silver nanoparticles, to the luminescence efficiency of Y2O3: Eu3+ red-emitting phosphors. Various Ag concentrations (1, 2.5 and 5 wt. %) and heat-treatment regimes (as prepared, 2h, 12h) were applied to understand how size and distribution of the Ag nanoparticles affect the luminescence efficiency. Samples were characterized by TEM, XRPD and STEM to evaluate crystal structure and distribution of Eu3+ in Y2O3 matrix. In terms of Y, O and Eu ions, uniform distribution was observed in the particles interior, while the Ag is present at the particles surface showing that USP is feasible for synthesis of hierarchically organized Y2O3:Eu3+@Ag. In the case of higher Ag concentration, a deviation from uniform and finely distributed Ag nanoparticles on Y2O3:Eu3+ surface was detected having detrimental effect to the plasmon enhanced luminescence. Regardless from silver concentrations, all heat treated samples exhibited superior luminescence with respect to asprepared ones, while decrease of luminescence efficiency was detected with the increase of Ag concentration. The most intense red luminescence at 612 nm which is due Eu3+ 5D0→7F2 transition was observed in Y2O3:Eu3+@Ag system for sample with 1wt% Ag, annealed for 12 hours
Electricity Reform and Retail Pricing in Texas
Electricity market reforms have pursued two main goals, both aimed at increasing economic efficiency. The first is to make prices more reflective of costs so that consumers can make more efficient decisions about where and when to consume electricity. The second goal is to ensure that suppliers minimize the costs of supply. How successful has electricity market reform in Texas been with regard to achieving these goals? We focus on one aspect of this overall set of desired outcomes, namely whether movements in retail prices reflect wholesale market prices and whether reform has delivered cost reductions in the delivery of energy services by retailers. We find clear evidence that retail prices in competitive market areas better reflect wholesale prices and have moved favorably for consumers relative to wholesale prices. The same is not necessarily true for consumers in non-competitive market areas. This suggests that competitive retail markets have delivered cost reductions consistent with electricity service providers reducing their marginal costs. The effort that Texas undertook over a decade ago to introduce competition into the retail electricity supply thus appears to be yielding the benefits to consumers that were intended in competitive areas. Consumers in less competitive areas do not appear to have benefited as much
Kinetics of nanocrystalline phase transformations in spray pyrolysed ZnO particles
The thermal behavior of ZnO powder obtained by ultrasonic spray pyrolysis of nitrate solution (c=0.8mol/dm3, D0=2.695µm, Tmax=6000C, FG=1.2dm3/min) was investigated using non-isothermal differential scanning calorimetry (DSC, heating rates 5, 10, 15, 20O/min). The exothermic heat effects at the temperature range from 350 to 5000C were linked to particles structural data obtained by XRD, SEM and TEM analysis. Produced particles are characterized by uniform submicronic size (D=800nm, BET=4.94m2/g), high phase purity and granular or circular “open” surface due to the presence of primary crystallites (d= 20nm). Observed structural changes during heating of this powder were attributed to simultaneous processes of nucleation and growth of primary crystallites inside the produced particles
Tunable crystal structure and proton conductivity of lanthanide nitrilotrismethylphosphonates
Metal phosphonates are multifunctional solids with remarkable stability and proton conducting properties owing
to their structure is usually composed of extended hydrogen-bond networks that favor proton transfer pathways [1].
Moreover, these properties can be enhanced by appropriate modification of the synthesis conditions [2, 3].
In this communication, a new family of isostructural 2D layered compounds based on lanthanide nitrilotris-methylphosphonates
is reported. These compounds have been isolated at room temperature and have the general formula Ln[N(CH2)3(PO3H2)2(PO3H)(H2O)]SO4·2H2O (Ln= Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb). The coordination environment
of Ln3+ is composed by eight oxygen atoms from three different ligands and two oxygens from bound waters.
This connectivity creates positive charged layers connected to sulfate ions through hydrogen-bonds. These compounds
show promising proton conductivity with values ranging between 7.6·10-2 and 3.8·10-2 S·cm-1 at 80 °C and 95% RH
and low activation energy corresponding to Grotthuss-type proton transfer mechanism. In addition, a structural transformation
occurs at T > 70 °C accompanied by a remarkable enhanced conductivity. Studies on the structure-properties relationships will be discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.
MINECO: MAT2016-77648-R
Junta Andalucía: P12-FQM-1656 y FQM-11
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