Die Identität von Fremdsprachlehrenden und die problematischen Effekte der Dichotomie native speaker/non native speaker

The present paper aims to gain a better understanding of the language teachers’ identity in relation to their first language. Hybrid, poststructuralist concepts conflict with the still dominant figure of the native speaker, that represents an ideal whereby the identity of language teachers is categorized simply as either native speakers of a particular language, or non-native speakers (Braine 2010, Medgyes 1994, Moussu, Llurda 2008, Murti 2002). This dichotomic vision establishes a hierarchical relationship in which the identity of language teachers is determined exclusively by a connection between language and birth (‘native’), without necessarily considering the effective linguistic and didactic competence of the teachers, and other such factors relevant in teaching practice. Here, the concept of the ‘native speaker language teacher’ (NSLT) (Riordan 2018) is critically analyzed and discussed: In place of a dichotomic vision, I propose an interlanguage continuum (Selinker 1972) with ‘zero proficiency’ and ‘absolute proficiency’ at the two poles. Within this continuum, all language teachers, both native and non-native, may occupy a specific stage depending on their language proficiency. Furthermore, in contrast with the image of the native speaker, I present alternative perspectives based on the effective language use of the teacher, that also include other essential didactic aspects, such as multilingualism and intercultural competence

Self-perception of teachers with German L1 or LX concerning their teaching behaviour in GFL classes

n der Fremdsprachendidaktik war man lange der Ansicht, dass native speakers im Vergleich zu ihren nichtmuttersprachlichen Kollegen kompetentere Sprachlehrende sind. Allerdings setzt sich die LehrLern-Forschung mit genau dieser Diskussion erst seit den 1990er Jahren auseinander, und fast nur im EFL/ ESL-Bereich. In diesen ersten Studien zeigte sich eine Dichotomie zwischen native und non-native speakers, nach der die zwei «Gruppen» ihren persönlichen Einschätzungen zufolge anders unterrichteten (Medgyes 1994). Der vorliegende Beitrag untersucht die Selbstwahrnehmung von DaF-Lehrer*innen mit Deutsch L1 und LX hinsichtlich ihres Verhaltens im Unterricht, um herauszufinden, ob diese in verschiedenen Studien dargestellte Dichotomie ebenfalls im DaF-Bereich auftritt. 60 Lehrkräfte verschiedener Universitäten und GoetheInstitute in Spanien und Portugal haben an einer Umfrage teilgenommen, deren Auswertung die Ergebnisse anderer Studien der EFL/ESL-Didaktik teilweise bestätigt, allerdings nur als mögliche Tendenzen oder Präferenzen. In den meisten Fällen zeigen die Befragten abgesehen von ihrer Erstsprache nur sehr wenige Unterschiede.In foreign language didactics it was long thought that native speakers were more competent language teachers in comparison to their non-native speaking counterparts. Beginning in the 1990s language teaching and learning research examined this topic, almost exclusively in the EFL/ESL area. These initial studies showed a dichotomy between native and non-native speakers, which in turn exhibited different self-perception in terms of teaching attitudes (Medgyes 1994). The current study investigates the self-perception of native and non-native GFL teachers with respect to their teaching behaviour in order to determine if the aforementioned dichotomy is also present in the GFL area. 60 teachers from various universities and Goethe institutes in Spain and Portugal took part in a survey, whose results only partly supported other EFL/ESL didactics studies, as it was shown that the differences were little more than tendencies or preferences. Most of those surveyed showed very little differences relating to their first language

Iron entry route in horse spleen apoferritin Involvement of the three-fold channels as probed by selective reaction of cysteine-126 with the spin label 4-maleimido-tempo

AbstractApoferritin has been selectively labeled with a maleimide nitroxide derivative at Cys-126, located in the hydrophilic 3-fold channels. Titration of this derivative with Fe(II), which gives rise to the initial Fe(III)-apoferritin complex, produces, at low metal-to-protein ratios, a decrease of the intensity of the label EPR signal due to the occurrence of a magnetic dipolar interaction. A label-metal distance ranging between 8–12 Å can be estimated from titrations performed with VO(IV), which is known to bind in the 3-fold channels, and likewise produces a decrease in the label EPR signal. The present findings indicate that iron binds in the hydrophilic channels in its higher oxidation slate and that these channels represent the metal entry route at least at low metal-to-protein ratios

Magnetic resonance imaging and previous cesarean section in placenta accrete spectrum disorder: Predictor model

Objective: To evaluate objective criteria of Magnetic Resonance Imaging (MRI) of Placenta Accreta Spectrum disorder (PAS) analyzing interobserver agreement and to derive a model including imaging and clinical variables to predict PAS. Methods: A retrospective review including patients submitted to MRI with suspicious findings of PAS on ultrasound. Exclusion criteria were lack of pathology or surgical information and missing or poor-quality MRI. Two radiologists analyzed six MRI features, and significant clinical data were also recorded. PAS confirmed on pathology or during intraoperative findings were considered positive for the primary outcome. Variables were tested through logistic regression models. Results: Final study included 96 patients with a mean age of 33 years and 73.0% of previous C-sections. All MRI features were significantly associated with PAS for both readers. After logistic regression fit, including MRI signs with a moderate or higher interobserver agreement, intraplacental T2 dark band was the most significant radiologic criteria, and ROC analysis resulted in an AUC = 0.782. After including the most relevant clinical data (previous C-section) to the model, the ROC analysis improved to an AUC = 0.893. Conclusion: Simplified objective criteria on MRI, including intraplacental T2 dark band associated with clinical information of previous C-sections, had the highest accuracy and was used for a predictive model of PAS

Tempol-nebivolol therapy potentiates hypotensive effect increasing NO bioavailability and signaling pathway

Nebivolol is a third generation beta blocker with endothelial nitric oxide synthase (eNOS) agonist properties. Considering the role of reactive oxygen species (ROS) in the uncoupling of eNOS, we hypothesized that the preadministration of an antioxidant as tempol, could improve the hypotensive response of nebivolol in normotensive animals increasing the nitric oxide (NO) bioavailability by a reduction of superoxide (O2•−) basal level production in the vascular tissue. Male Sprague Dawley rats were given tap water to drink (control group) or tempol (an antioxidant scavenger of superoxide) for 1 week. After 1 week, Nebivolol, at a dose of 3 mg/kg, was injected intravenously to the control group or to the tempol-treated group. Mean arterial pressure, heart rate, and blood pressure variability were evaluated in the control, tempol, nebivolol, and tempol nebivolol groups, as well as, the effect of different inhibitor as Nβ-nitro-l-arginine methyl ester (L-NAME, a Nitric oxide synthase blocker) or glybenclamide, a KATP channel inhibitor. Also, the expression of α,β soluble guanylate cyclase (sGC), phospho-eNOS, and phospho-vasodilator-stimulated phosphoprotein (P-VASP) were evaluated by Western Blot and cyclic guanosine monophosphate (cGMP) levels by an enzyme-linked immunosorbent assay (ELISA) commercial kit assay. We showed that pretreatment with tempol in normotensive rats produces a hypotensive response after nebivolol administration through an increase in the NO bioavailability and sGC, improving the NO/cGMP/protein kinase G (PKG) pathway compared to that of the nebivolol group. We demonstrated that tempol preadministration beneficiates the response of a third-generation beta blocker with eNOS stimulation properties, decreasing the basal uncoupling of eNOS, and improving NO bioavailability. Our results clearly open a possible new strategy therapeutic for treating hypertension.Fil: Bertera, Facundo Martin. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Santa Cruz, Diego Mario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Balestrasse, Karina Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gorzalczany, Susana Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Höcht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Taira, Carlos Alberto. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polizio, Ariel Héctor. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Three-dimensional simulation of clouds of multi-disperse evaporating saliva droplets in a train cabin

In line with recent ongoing efforts to collect crucial information about the mechanisms of virus diffusion and put them in relation to the effective complexity of the several natural or artificial environments where human beings leave and operate, the present study deals with the dispersion of evaporating saliva droplets in the cabin of an interregional train. A relevant physical model is constructed taking into account the state of the art in terms of existing paradigms and their ability to represent some fundamental aspects related to the evolution in time of a cloud of multi-disperse droplets. Conveniently, such a theoretical framework is turned into a computational one that relies on low Mach-number asymptotics and can therefore take advantage of the typical benefits (relatively low computational cost) associated with pressure-based methods. Numerical simulations are used to predict the flow established in the cabin as a result of the ventilation systems and related settings dictated by considerations on passenger comfort. The solution of two-way coupled Lagrangian evolution equations is used to capture the associated dynamics of the dispersed phase and predict its transport in conjunction with the peculiar topology of the considered flow and morphology of solid surfaces, which bound it (including the human beings). Typical physiological processes such as talking or coughing are considered. An analysis on the impact of the multiplicity of droplet sources is also conducted, thereby providing some indications in terms of potential risks for the cabin occupants

Functional divergence in the role of N-linked glycosylation in smoothened signaling

The G protein-coupled receptor (GPCR) Smoothened (Smo) is the requisite signal transducer of the evolutionarily conserved Hedgehog (Hh) pathway. Although aspects of Smo signaling are conserved from Drosophila to vertebrates, significant differences have evolved. These include changes in its active sub-cellular localization, and the ability of vertebrate Smo to induce distinct G protein-dependent and independent signals in response to ligand. Whereas the canonical Smo signal to Gli transcriptional effectors occurs in a G protein-independent manner, its non-canonical signal employs Gαi. Whether vertebrate Smo can selectively bias its signal between these routes is not yet known. N-linked glycosylation is a post-translational modification that can influence GPCR trafficking, ligand responsiveness and signal output. Smo proteins in Drosophila and vertebrate systems harbor N-linked glycans, but their role in Smo signaling has not been established. Herein, we present a comprehensive analysis of Drosophila and murine Smo glycosylation that supports a functional divergence in the contribution of N-linked glycans to signaling. Of the seven predicted glycan acceptor sites in Drosophila Smo, one is essential. Loss of N-glycosylation at this site disrupted Smo trafficking and attenuated its signaling capability. In stark contrast, we found that all four predicted N-glycosylation sites on murine Smo were dispensable for proper trafficking, agonist binding and canonical signal induction. However, the under-glycosylated protein was compromised in its ability to induce a non-canonical signal through Gαi, providing for the first time evidence that Smo can bias its signal and that a post-translational modification can impact this process. As such, we postulate a profound shift in N-glycan function from affecting Smo ER exit in flies to influencing its signal output in mice

Reduced primary cilia length and altered Arl13b expression are associated with deregulated chondrocyte Hedgehog signaling in alkaptonuria

This work was supported by the Medical Research Council (MR/L002876/1), the Royal College of Surgeons of England, Fondazione Telethon Italy (GGP10058), and Associazione Italiana Malati di Alcaptonuria (AimAKU, ORPHA263402

ACE2-Mediated Reduction of Oxidative Stress in the Central Nervous System Is Associated with Improvement of Autonomic Function

Oxidative stress in the central nervous system mediates the increase in sympathetic tone that precedes the development of hypertension. We hypothesized that by transforming Angiotensin-II (AngII) into Ang-(1–7), ACE2 might reduce AngII-mediated oxidative stress in the brain and prevent autonomic dysfunction. To test this hypothesis, a relationship between ACE2 and oxidative stress was first confirmed in a mouse neuroblastoma cell line (Neuro2A cells) treated with AngII and infected with Ad-hACE2. ACE2 overexpression resulted in a reduction of reactive oxygen species (ROS) formation. In vivo, ACE2 knockout (ACE2−/y) mice and non-transgenic (NT) littermates were infused with AngII (10 days) and infected with Ad-hACE2 in the paraventricular nucleus (PVN). Baseline blood pressure (BP), AngII and brain ROS levels were not different between young mice (12 weeks). However, cardiac sympathetic tone, brain NADPH oxidase and SOD activities were significantly increased in ACE2−/y. Post infusion, plasma and brain AngII levels were also significantly higher in ACE2−/y, although BP was similarly increased in both genotypes. ROS formation in the PVN and RVLM was significantly higher in ACE2−/y mice following AngII infusion. Similar phenotypes, i.e. increased oxidative stress, exacerbated dysautonomia and hypertension, were also observed on baseline in mature ACE2−/y mice (48 weeks). ACE2 gene therapy to the PVN reduced AngII-mediated increase in NADPH oxidase activity and normalized cardiac dysautonomia in ACE2−/y mice. Altogether, these data indicate that ACE2 gene deletion promotes age-dependent oxidative stress, autonomic dysfunction and hypertension, while PVN-targeted ACE2 gene therapy decreases ROS formation via NADPH oxidase inhibition and improves autonomic function. Accordingly, ACE2 could represent a new target for the treatment of hypertension-associated dysautonomia and oxidative stress