426 research outputs found
The 'native speaker' spin: the construction of the English teacher at a language department at a university in central Mexico
This is a study of how teachers, students and administrators in a particular university's language department in Guanajuato, Mexico, construct the English teachers' professional image. The experiences of ten teachers, fourteen students, and two administrators at the Language Department of the University of Guanajuato in Mexico are explored through data obtained from conversations, narratives, critical incidents, e-mail correspondence and field-notes.
This thesis began as an investigation of the construction of the 'native/non-native' debate. However, it arrived at a final point which is concerned about the ways in which individual perceptions are constructed and affected through historical or social pressures. From the data collected key areas emerged, such as: identity, labelling and the socio-political relationship between Mexico and the United States and its consequences. The data shows the polarization that exists between 'native speakers' and 'non-native speakers' themselves concerning aspects such as birthplace, ethnicity and nationality. In order to make sense of this data, I decided to employ the concept of spin to explain how images of the English teacher and speaker are constructed and maintained (or rejected) by participants. This is used as a lens to understand the evolution of the creation of the 'native speaker' image and labels. This helps understand how the 'native speaker' image came to play such a critical —and sometimes apparently harmful— role in the construction of the Other and the Self. Specifically, the 'native speaker' spin was not a point of investigation, but emerged as a significant tool for the discussion of the data as the analysis progressed.
Overall this study seems to set a precedent that there is no clear-cut division between 'native' and 'non-native speakers'. Rising awareness of how complex labels operate through discourses, institutions and hiring policies may help to bring about more recognition of commonalities of English teachers as professionals
Characterization of the Adherence of Clostridium difficile Spores: The Integrity of the Outermost Layer Affects Adherence Properties of Spores of the Epidemic Strain R20291 to Components of the Intestinal Mucosa
Indexación: Web of Science.Clostridium difficile is the causative agent of the most frequently reported nosocomial diarrhea worldwide. The high incidence of recurrent infection is the main clinical challenge of C. difficile infections (CBI). Formation of C. difficile spores of the epidemic strain R20291 has been shown to be essential for recurrent infection and transmission of the disease in a mouse model. However, the underlying mechanisms of how these spores persist in the colonic environment remains unclear. In this work, we characterized the adherence properties of epidemic R20291 spores to components of the intestinal mucosa, and we assessed the role of the exosporium integrity in the adherence properties by using cdeC mutant spores with a defective exosporium layer. Our results showed that spores and vegetative cells of the epidemic R20291 strain adhered at high levels to monolayers of Caco-2 cells and mucin. Transmission electron micrographs of Caco-2 cells demonstrated that the hair-like projections on the surface of R20291 spores are in close proximity with the plasma membrane and microvilli of undifferentiated and differentiated monolayers of Caco-2 cells. Competitive-binding assay in differentiated Caco-2 cells suggests that spore-adherence is mediated by specific binding sites. By using spores of a cdeC mutant we demonstrated that the integrity of the exosporium layer determines the affinity of adherence of C. difficile spores to Caco-2 cells and mucin. Binding of fibronectin and vitronectin to the spore surface was concentration-dependent, and depending on the concentration, spore-adherence to Caco-2 cells was enhanced. In the presence of an aberrantly-assembled exosporium (cdeC spores), binding of fibronectin, but not vitronectin, was increased. Notably, independent of the exosporium integrity, only a fraction of the spores had fibronectin and vitronectin molecules binding to their surface. Collectively, these results demonstrate that the integrity of the exosporium layer of strain R20291 contributes to selective spore adherence to components of the intestinal mucosa.http://journal.frontiersin.org/article/10.3389/fcimb.2016.00099/ful
Riqueza, abundancia relativa y actividad de los mamíferos de una reserva en restauración en Costa Rica
ABSTRACT. “Richness, relative abundance and activity of medium and large mammals of a reserve under restoration in Costa Rica”. Introduction: Private protected areas are a valuable complement to national systems of protected areas. The Sierra Zapote Reserve in Abangares, Costa Rica, established in 2000, protects 70 ha of advanced secondary forest, regenerating secondary forest and primary riparian forest. It is expected to favor faunal communities, like medium and large mammals, which are among the species most threatened by habitat loss and fragmentation; nevertheless; there is a lack of recent faunal assessments at Sierra Zapote. Objective: To assess the richness, relative abundance and activity patterns of these mammals in the reserve. Methods: From May 2020 to July 2021, we kept five camera-traps at strategic sites and programmed them to be active 24 hours a day (0,3 seconds between shots). We checked the cameras every one or two months and also extracted temperature and moon phase data. Results: We obtained 758 independent records of mammals with a 2 135-day photo-trapping effort. The most abundant species were Nasua narica (relative abundance index RAI = 14,6, N= 312) and Didelphis marsupialis (RAI = 6,1, N= 130). The least abundant were Herpailurus yagouaroundi and Procyon lotor (RAI = 0,05, N= 1). Most species are nocturnal and only the peccary (Pecari tajacu), the coati (Nasua narica) and the agouti (Dasyprocta punctata) have mostly diurnal activity. The puma (Puma concolor) occurs at the reserve. Conclusion: The activity patterns were as expected; for the reserve size, a richness of 19 species is comparatively high. The presence of the puma, an indicator of good ecosystem health, hints at the importance of the reserve’s restoration process.RESUMEN. Introducción: Las áreas protegidas privadas son un complemento valioso para los sistemas nacionales de áreas protegidas. La Reserva Sierra Zapote en Abangares, Costa Rica, establecida en 2000, protege 70 ha de bosque secundario avanzado, bosque secundario en regeneración y bosque ribereño primario. Se espera que favorezca a las comunidades faunísticas, como los mamíferos medianos y grandes, que se encuentran entre las especies más amenazadas por la pérdida y fragmentación del hábitat; actualmente existe la necesidad de evaluaciones faunísticas en Sierra Zapote. Objetivo: Evaluar la riqueza, abundancia relativa y patrones de actividad de estos mamíferos en la reserva. Métodos: De mayo de 2020 a julio de 2021, mantuvimos cinco cámaras trampa en sitios estratégicos y las programamos para que estuvieran activas las 24 horas del día (0,3 segundos entre disparos). Revisamos las cámaras cada 1-2 meses y también extrajimos datos de temperatura y fase lunar. Resultados: Obtuvimos 758 registros independientes de mamíferos con un esfuerzo de fototrampeo de 2 135 días. Las especies más abundantes fueron Nasua narica (índice de abundancia relativa RAI = 14,6, N= 312) y Didelphis marsupialis (RAI = 6,1, N= 130). Los menos abundantes fueron Herpailurus yagouaroundi y Procyon lotor (RAI = 0,05, N= 1). La mayoría de las especies son nocturnas y solo el saíno (Pecari tajacu), el pizote (Nasua narica) y la guatusa (Dasyprocta punctata) tienen actividad mayoritariamente diurna. El puma (Puma concolor) también habita en la reserva. Conclusión: Los patrones de actividad fueron los esperados; para el tamaño de la reserva, una riqueza de 19 especies es comparativamente alta. La presencia del puma, indicador de buena salud del ecosistema, deja entrever la importancia del proceso de restauración de la reserva
Genomic and proteomic analyses reveal a relationship between WNT pathway, genes, oxidative stress metabolism and vascular calcification
Comunicaciones a congreso
Placental thrombosis in acute phase abortions during experimental Toxoplasma gondii infection in sheep
43 p.After oral administration of ewes during mid gestation with 2000 freshly prepared sporulated oocysts of T. gondii
isolate M4, abortions occurred between days 7 and 11 in 91.6% of pregnant and infected ewes. Afterwards, a
further infection was carried out at late gestation in another group of sheep with 500 sporulated oocysts. Abortions
happened again between days 9 and 11 post infection (pi) in 58.3% of the infected ewes. Classically, abortions in
natural and experimental ovine toxoplasmosis usually occur one month after infection. Few experimental studies
have reported the so-called acute phase abortions as early as 7 to 14 days after oral inoculation of oocysts, and
pyrexia was proposed to be responsible for abortion, although the underline mechanism was not elucidated. In the
present study, all placentas analysed from ewes suffering acute phase abortions showed infarcts and thrombosis in
the caruncullar villi of the placentomes and ischemic lesions (periventricular leukomalacia) in the brain of some
foetuses. The parasite was identified by PCR in samples from some placentomes of only one sheep, and no antigen
was detected by immunohistochemical labelling. These findings suggest that the vascular lesions found in the
placenta, and the consequent hypoxic damage to the foetus, could be associated to the occurrence of acute phase
abortions. Although the pathogenesis of these lesions remains to be determined, the infectious dose or virulence
of the isolate may play a role in their developmentS
Effects of an Exercise Program on Brain Health Outcomes for Children With Overweight or Obesity. The ActiveBrains Randomized Clinical Trial
IMPORTANCE Pediatric overweight and obesity are highly prevalent across the world, with
implications for poorer cognitive and brain health. Exercise might potentially attenuate these
adverse consequences.
OBJECTIVES To investigate the effects of an exercise program on brain health indicators, including
intelligence, executive function, academic performance, and brain outcomes, among children with
overweight or obesity and to explore potential mediators and moderators of the main effects of
exercise.
DESIGN, SETTING, AND PARTICIPANTS All preexercise and postexercise data for this 20-week
randomized clinical trial of 109 children aged 8 to 11 years with overweight or obesity were collected
from November 21, 2014, to June 30, 2016, with neuroimaging data processing and analyses
conducted between June 1, 2017, and December 20, 2021. All 109 children were included in the
intention-to-treat analyses; 90 children (82.6%) completed the postexercise evaluation and
attended 70%or more of the recommended exercise sessions and were included in per-protocol
analyses.
INTERVENTIONS All participants received lifestyle recommendations. The control group continued
their usual routines, whereas the exercise group attended a minimum of 3 supervised 90-minute
sessions per week in an out-of-school setting.
MAIN OUTCOMES AND MEASURES Intelligence, executive function (cognitive flexibility,
inhibition, andworking memory), and academic performancewere assessed with standardized tests,
and hippocampal volume was measured with magnetic resonance imaging.
RESULTS The 109 participants included 45 girls (41.3%); participants had a mean (SD) body mass
index of 26.8 (3.6) and a mean (SD) age of 10.0 (1.1) years at baseline. In per-protocol analyses, the
exercise intervention improved crystallized intelligence, with the exercise group improving from
before exercise to after exercise (mean z score, 0.62 [95%CI, 0.44-0.80]) compared with the
control group (mean z score, –0.10 [95%CI, –0.28 to 0.09]; difference between groups, 0.72 SDs
[95%CI, 0.46-0.97]; P < .001). Total intelligence also improved significantly more in the exercise
group (mean z score, 0.69 [95%CI, 0.48-0.89]) than in the control group (mean z score, 0.07 [95%
CI, –0.14 to 0.28]; difference between groups, 0.62 SDs [95%CI, 0.31-0.91]; P < .001). Exercise also
positively affected a composite score of cognitive flexibility (mean z score: exercise group, 0.25 [95%
CI, 0.05-0.44]; control group, –0.17 [95%CI, –0.39 to 0.04]; difference between groups, 0.42 SDs
[95%CI, 0.13-0.71]; P = .005). These main effects were consistent in intention-to-treat analyses and after multiple-testing correction. There was a positive, small-magnitude effect of exercise on total
academic performance (mean z score: exercise group, 0.31 [95%CI, 0.18-0.44]; control group, 0.10
[95%CI, –0.04 to 0.24]; difference between groups, 0.21 SDs [95%CI, 0.01-0.40]; P = .03), which
was partially mediated by cognitive flexibility. Inhibition, working memory, hippocampal volume,
and other brain magnetic resonance imaging outcomes studied were not affected by the exercise
program. The intervention increased cardiorespiratory fitness performance as indicated by longer
treadmill time to exhaustion (mean z score: exercise group, 0.54 [95%CI, 0.27-0.82]; control group,
0.13 [95%CI, –0.16 to 0.41]; difference between groups, 0.42 SDs [95%CI, 0.01-0.82]; P = .04), and
these changes in fitness mediated some of the effects (small percentage of mediation
[approximately 10%-20%]). The effects of exercise were overall consistent across the moderators
tested, except for larger improvements in intelligence among boys compared with girls.
CONCLUSIONS AND RELEVANCE In this randomized clinical trial, exercise positively affected
intelligence and cognitive flexibility during development among children with overweight or obesity.
However, the structural and functional brain changes responsible for these improvementswere not
identified.Spanish Government DEP2013-47540
DEP2016-79512-R
DEP2017-91544-EXPEuropean Commission
European Commission
European Commission Joint Research Centre 667302Alicia Koplowitz FoundationERDF (FEDER in Spanish) B-CTS-355-UGR18University of Granada, Plan Propio de Investigacion, Visiting Scholar grantsJunta de AndaluciaUnit of Excellence on Exercise, Nutrition and Health (UCEENS)European Commission SOMM17/6107/UGREXERNET Research Network on Exercise and Health DEP2005-00046/ACTIHigh Council of Sports 09/UPB/19Spanish Government FPU 14/06837
FPI-BES-2014-068829
FJC2018-037925-I
FJCI-2014-19563
IJCI-2017-33642
RYC2019-027287-I
FPU15/02645
FJCI-2017-33396
IJC2019-041916-IJunta de AndaluciaNational Agency for Research and Development (ANID)/BECAS Chile 72180543Ramon Areces Foundatio
Taxonomic and functional metagenomic profiling of the microbial community in the anoxic sediment of a sub-saline Shallow Lake (Laguna de Carrizo, Central Spain)
The phylogenetic and functional structure of the microbial community residing in a Ca2+-rich anoxic sediment of a sub-saline shallow lake (Laguna de Carrizo, initially operated as a gypsum (CaSO4 × 2 H2O) mine) was estimated by analyzing the diversity of 16S rRNA amplicons and a 3.1 Mb of consensus metagenome sequence. The lake has about half the salinity of seawater and possesses an unusual relative concentration of ions, with Ca2+ and SO 4 2- being dominant. The 16S rRNA sequences revealed a diverse community with about 22% of the bacterial rRNAs being less than 94.5% similar to any rRNA currently deposited in GenBank. In addition to this, about 79% of the archaeal rRNA genes were mostly related to uncultured Euryarchaeota of the CCA47 group, which are often associated with marine and oxygen-depleted sites. Sequence analysis of assembled genes revealed that 23% of the open reading frames of the metagenome library had no hits in the database. Among annotated genes, functions related to (thio) sulfate and (thio) sulfonate-reduction and iron-oxidation, sulfur-oxidation, denitrification, synthrophism, and phototrophic sulfur metabolism were found as predominant. Phylogenetic and biochemical analyses indicate that the inherent physical–chemical characteristics of this habitat coupled with adaptation to anthropogenic activities have resulted in a highly efficient community for the assimilation of polysulfides, sulfoxides, and organosulfonates together with nitro-, nitrile-, and cyanide-substituted compounds. We discuss that the relevant microbial composition and metabolic capacities at Laguna de Carrizo, likely developed as an adaptation to thrive in the presence of moderate salinity conditions and potential toxic bio-molecules, in contrast with the properties of previously known anoxic sediments of shallow lakes.This research was supported by the Spanish CSD2007-00005 project and FEDER funds. M-E.G. thanks the CSIC for a JAE fellowship.Peer Reviewe
Anisotropic normal-state properties of the MgB2 superconductor
Based on the experimentally found existence of two gaps in MgB2 (one gap
associated to the boron sigma-states and the other to the boron pi-states), the
different contributions to the transport properties, electrical conductivity
and Hall coefficient, were studied using the full potential-linearized
augmented plane wave method and the generalized gradient approximation. MgB2
doping was analyzed in the rigid band approximation. This permitted the study
of the partial substitution of magnesium for aluminium (Mg1-xAlxB2) as well as
other substitutions such as AB2 (A=Be, Zr, Nb and Ta). The sigma-bands (boron
sigma-states), which are associated to the large superconducting gap, are very
anisotropic at EF, while the pi-bands have very little anisotropic character.
In (Mg1-xAlxB2) Tc diminishes with Al content, the other compounds are not
superconductors. In this work it was found that with electron doping, such as
Al substitution, the sigma-band conductivity decreases and the corresponding
bands become less anisotropic. sigma-band contribution for BeB2 and ScB2 at EF
is very small and the anisotropy is much lower. For Zr, Nb and Ta there are no
sigma-bands at EF. These results give a connection between superconductivity
and the character of the sigma-band; band conductivity and band anisotropy.
This gives a plausible explanation for the diminution of Tc with different
doping of MgB2
The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients
Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation
Why Firms Relocate Their Production Overseas? The Answer Lies Inside: Corporate, Logistic and Technological Determinants
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