Perceived learning difficulty and actual performance: Explicit and Implicit Knowledge of L2 English Grammar Points among Instructed Adult Learners

This article draws on an approach that conceptualizes L2 learning difficulty in terms of implicit and explicit knowledge. In a study with first language Mexican Spanish university-level learners (n = 30), their teachers (n = 11), and applied linguistics experts (n = 3), we investigated the relationship between (a) these groups' difficulty judgements of 13 selected L2 English structures and (b) perceived learning difficulty and learners' actual performance on measures of implicit and explicit knowledge. Our findings show that experts' learning difficulty judgements did not lead to significant predictions, whereas the learners' own difficulty rankings correlated significantly with their performance on the measure of explicit knowledge. Although correlations based on teachers' difficulty rankings did not reach statistical significance, the judgements of this group were the only ones that showed trends toward successful prediction of learners' performance on both the implicit and the explicit L2 measures. Thus the teachers exhibited a trend toward the best overall prediction ability

Origin of the Significant Impact of Ta on the Creep Resistance of FeCrNi Alloys

Heat resistant FeCrNi alloys are widely used in the petrochemical industry because they exhibit a unique combination of creep and oxidation resistance at temperatures exceeding 900$^\circ$C. Their creep properties are often optimized by micro-additions of carbide forming elements. In the present work, the influence of Ta micro-additions has been experimentally investigated both on as-cast and aged microstructures to understand the origin of the significant impact of this element on the creep resistance. Calculations with thermocal software were also carried out to support experimental data. It is shown that a small addition of Ta is beneficial as it increases the volume fraction of stable MC carbides. We demonstrate also that additions of Ta may have a dramatic effect on the thermal stability of microstructures. This is attributed to a smaller equilibrium volume fraction of M23C6 and more pronounced heterogeneous precipitation at MC/matrix interfaces. The influence on the creep properties in then discussed

General multimode polarization splitter design in uniaxial media

Quasiconformal transformation optics is used to design two-dimensional polarization beam splitters. The resulting media present inhomogeneous uniaxial permittivity and nonmagnetic response. The compact devices are theoretically designed and investigated for symmetrical and asymmetrical geometries, with footprint of 64 and 110 mu m(2), respectively. The polarization splitter performance is evaluated for the fundamental mode and third mode, exhibiting an insertion loss closer to 0 dB and extinction ratio above 40 dB over a broad wavelength range573CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGnão temnão temnão te

Spatio-temporal analysis of the role of climate in inter-annual variation of malaria incidence in Zimbabwe

BACKGROUND: On the fringes of endemic zones climate is a major determinant of inter-annual variation in malaria incidence. Quantitative description of the space-time effect of this association has practical implications for the development of operational malaria early warning system (MEWS) and malaria control. We used Bayesian negative binomial models for spatio-temporal analysis of the relationship between annual malaria incidence and selected climatic covariates at a district level in Zimbabwe from 1988–1999. RESULTS: Considerable inter-annual variations were observed in the timing and intensity of malaria incidence. Annual mean values of average temperature, rainfall and vapour pressure were strong positive predictors of increased annual incidence whereas maximum and minimum temperature had the opposite effects. Our modelling approach adjusted for unmeasured space-time varying risk factors and showed that while year to year variation in malaria incidence is driven mainly by climate, the resultant spatial risk pattern may to large extent be influenced by other risk factors except during high and low risk years following the occurrence of extremely wet and dry conditions, respectively. CONCLUSION: Our model revealed a spatially varying risk pattern that is not attributable only to climate. We postulate that only years characterized by extreme climatic conditions may be important for developing climate based MEWS and for delineating areas prone to climate driven epidemics. However, the predictive value of climatic risk factors identified in this study still needs to be evaluated

Familial ATTR amyloidosis: microalbuminuria as a predictor of symptomatic disease and clinical nephropathy

Familial ATTR amyloidosis: microalbuminuria as a predictor of symptomatic disease and clinical nephropathy. Lobato L, Beirão I, Silva M, Bravo F, Silvestre F, Guimarães S, Sousa A, Noël LH, Sequeiros J. SourceDepartment of Nephrology and Centro de Estudos de Paramiloidose, Hospital Geral de Santo António and Institute for Molecular and Cell Biology, Porto, Portugal. [email protected] Abstract BACKGROUND: Portuguese type familial amyloid polyneuropathy (FAP) is a neuropathic amyloidosis caused by a mutant transthyretin (TTR). Varying degrees of renal involvement have been reported. Our aim was to assess the value of microalbuminuria (MA) for predicting clinical neurological disease and overt nephropathy in TTR-related amyloidosis. METHODS: All subjects had the TTR Val30Met mutation, and were recruited between 1993 and 1999. We have prospectively evaluated 22 asymptomatic gene carriers (7 male, 15 female; mean age 41.6+/-9.6 years) and 32 patients with neuropathy (14 male, 18 female; 36.8+/-8.8 years, on average, 33.0+/-9.3 years at the onset of neuropathy). We measured urinary albumin excretion every year, if asymptomatic, or every 6 months if already affected. Kidney biopsies were performed in patients with normal urinary albumin excretion, MA, and overt nephropathy, respectively. RESULTS: In asymptomatic carriers, persistent MA was detected in eight (36%) subjects. The presence of MA in asymptomatic gene carriers, compared with those having normal urinary albumin excretion, conferred a 4.8-fold risk of developing neuropathy, usually within the subsequent 3 years. Once neurological signs appeared, nephropathy, manifested as MA, progressed to overt nephropathy in one-half of subjects. In patients with neuropathy, 24 (75%) had MA during follow-up: evolution towards clinical renal disease occurred in 14 (58%) and renal failure occurred in five (21%), always after a course of MA. Proteinuria or renal failure without prior persistent MA were never observed in the present patient cohort. Histopathological evaluation did not reveal glomerular lesions other than amyloid deposits to explain abnormal urinary albumin excretion. The amount of mesangial and vascular-pole amyloid deposits was correlated with the degree of albuminuria. CONCLUSIONS: Microalbuminuria represents the first stage of clinical TTR amyloid nephropathy and is premonitory of neuropathy. Its presence identifies a subgroup of patients who are more prone to develop overt nephropathy. Screening of MA may be important to assess disease onset and to recommend liver transplantation in individuals at risk

Gating control of the cardiac sodium channel Nav1.5 by its β3-subunit involves distinct roles for a transmembrane glutamic acid and the extracellular domain.

The auxiliary β3-subunit is an important functional regulator of the cardiac sodium channel Nav1.5, and some β3 mutations predispose individuals to cardiac arrhythmias. The β3-subunit uses its transmembrane α-helix and extracellular domain to bind to Nav1.5. Here, we investigated the role of an unusually located and highly conserved glutamic acid (Glu-176) within the β3 transmembrane region and its potential for functionally synergizing with the β3 extracellular domain (ECD). We substituted Glu-176 with lysine (E176K) in the WT β3-subunit and in a β3-subunit lacking the ECD. Patch-clamp experiments indicated that the E176K substitution does not affect the previously observed β3-dependent depolarizing shift of V½ of steady-state inactivation but does attenuate the accelerated recovery from inactivation conferred by the WT β3-subunit. Removal of the β3-ECD abrogated both the depolarizing shift of steady-state inactivation and the accelerated recovery, irrespective of the presence or absence of the Glu-176 residue. We found that steady-state inactivation and recovery from inactivation involve movements of the S4 helices within the DIII and DIV voltage sensors in response to membrane potential changes. Voltage-clamp fluorometry revealed that the E176K substitution alters DIII voltage sensor dynamics without affecting DIV. In contrast, removal of the ECD significantly altered the dynamics of both DIII and DIV. These results imply distinct roles for the β3-Glu-176 residue and the β3-ECD in regulating the conformational changes of the voltage sensors that determine channel inactivation and recovery from inactivation