941 research outputs found
Designing and Piloting a Tool for the Measurement of the Use of Pronunciation Learning Strategies
What appears to be indispensable to drive the field forward and ensure that research findings will be comparable across studies and provide a sound basis for feasible pedagogic proposals is to draw up a classification of PLS and design on that basis a valid and reliable data collection tool which could be employed to measure the use of these strategies in different groups of learners, correlate it with individual and contextual variables, and appraise the effects of training programs. In accordance with this rationale, the present paper represents an attempt to propose a tentative categorization of pronunciation learning strategies, adopting as a point of reference the existing taxonomies of strategic devices (i.e. O'Malley and Chamot 1990; Oxford 1990) and the instructional options teachers have at their disposal when dealing with elements of this language subsystem (e.g. Kelly 2000; Goodwin 2001). It also introduces a research instrument designed on the basis of the classification that shares a number of characteristics with Oxford's (1990) Strategy Inventory for Language Learning but, in contrast to it, includes both Likert-scale and open-ended items. The findings of a pilot study which involved 80 English Department students demonstrate that although the tool requires considerable refinement, it provides a useful point of departure for future research into PLS
Data Acquisition and Processing Techniques for Voltage Contrast Measurements
The effects of several data acquisition techniques on the accuracy of voltage contrast measurements are studied. In particular, the effect of using a voltage reference region directly connected to an external voltage source in performing the image intensity-to-voltage mapping of a node whose voltage is to be determined is examined. This is found to allow improved voltage measurement. The actual reference curves were obtained by least squares fitting the measured intensity-voltage reference data alternately to a quadratic and a cubic function. In addition, various mapping algorithms are considered including ones based alternately on the use of unprocessed, subtracted and normalized data. Using these techniques, one should expect voltage errors with means of approximately 25 mV and standard deviations of approximately 160 mV even with an unmodified commercial SEM incorporating no additional hardware to increase precision
Photometric Redshifts for Galaxies in the GOODS Southern Field
We use extensive multi-wavelength photometric data from the Great
Observatories Origins Deep Survey (GOODS) to estimate photometric redshifts for
a sample of 434 galaxies with spectroscopic redshifts in the Chandra Deep Field
South. Using the Bayesian method, which incorporates redshift/magnitude priors,
we estimate photometric redshifts for galaxies in the range 18 < R (AB) < 25.5,
giving an rms scatter of 0.11. The outlier fraction is < 10%, with the
outlier-clipped rms being 0.047. We examine the accuracy of photometric
redshifts for several, special sub--classes of objects. The results for
extremely red objects are more accurate than those for the sample as a whole,
with rms of 0.051 and very few outliers (3%). Photometric redshifts for active
galaxies, identified from their X-ray emission, have a dispersion of 0.104,
with 10% outlier fraction, similar to that for normal galaxies. Employing a
redshift/magnitude prior in this process seems to be crucial in improving the
agreement between photometric and spectroscopic redshifts.Comment: Accepted for publication in ApJ
Dissecting the regulatory microenvironment of a large animal model of non-Hodgkin lymphoma: evidence of a negative prognostic impact of FOXP3+ T cells in canine B cell lymphoma.
The cancer microenvironment plays a pivotal role in oncogenesis, containing a number of regulatory cells that attenuate the anti-neoplastic immune response. While the negative prognostic impact of regulatory T cells (Tregs) in the context of most solid tissue tumors is well established, their role in lymphoid malignancies remains unclear. T cells expressing FOXP3 and Helios were documented in the fine needle aspirates of affected lymph nodes of dogs with spontaneous multicentric B cell lymphoma (BCL), proposed to be a model for human non-Hodgkin lymphoma. Multivariable analysis revealed that the frequency of lymph node FOXP3(+) T cells was an independent negative prognostic factor, impacting both progression-free survival (hazard ratio 1.10; p = 0.01) and overall survival (hazard ratio 1.61; p = 0.01) when comparing dogs showing higher than the median FOXP3 expression with those showing the median value of FOXP3 expression or less. Taken together, these data suggest the existence of a population of Tregs operational in canine multicentric BCL that resembles thymic Tregs, which we speculate are co-opted by the tumor from the periphery. We suggest that canine multicentric BCL represents a robust large animal model of human diffuse large BCL, showing clinical, cytological and immunophenotypic similarities with the disease in man, allowing comparative studies of immunoregulatory mechanisms.This is the published version of the manuscript. It was published in PLOS One and can be found here: http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0105027&representation=PD
Paradigms of flexibility: a systematic review of research on workplace flexibility
As flexibility has become a sine-qua-non of the contemporary workplace, we performed a critical review of its different uses and understandings in business and management research. Analyzing the literature on workplace flexibility in the period 1970-2018, using a four-part conceptual framework, and on the basis of subsequent content analysis of 262 most relevant publications, we identify two axes of tension embedding scholarly work on flexibility: the flexibility of vs. flexibility for organizations and employees, and a favorability-criticality tension. We further explain how internal divisions are attributable to three different paradigms of flexibility (two of which dominate), resulting from divergent sets of assumptions regarding: its target, rationale, approach to it, as well as methodologies involved in studying it. We propose a research agenda indicating the ways in which paradigmatic underpinnings of flexibility research may be further clarified and divisions between the paradigms made sense of
Rapid evolution of virulence and drug resistance in the emerging zoonotic pathogen Streptococcus suis
Background: Streptococcus suis is a zoonotic pathogen that infects pigs and can occasionally cause serious infections in
humans. S. suis infections occur sporadically in human Europe and North America, but a recent major outbreak has been
described in China with high levels of mortality. The mechanisms of S. suis pathogenesis in humans and pigs are poorly
understood.
Methodology/Principal Findings: The sequencing of whole genomes of S. suis isolates provides opportunities to
investigate the genetic basis of infection. Here we describe whole genome sequences of three S. suis strains from the same
lineage: one from European pigs, and two from human cases from China and Vietnam. Comparative genomic analysis was
used to investigate the variability of these strains. S. suis is phylogenetically distinct from other Streptococcus species for
which genome sequences are currently available. Accordingly, ,40% of the ,2 Mb genome is unique in comparison to
other Streptococcus species. Finer genomic comparisons within the species showed a high level of sequence conservation;
virtually all of the genome is common to the S. suis strains. The only exceptions are three ,90 kb regions, present in the two
isolates from humans, composed of integrative conjugative elements and transposons. Carried in these regions are coding
sequences associated with drug resistance. In addition, small-scale sequence variation has generated pseudogenes in
putative virulence and colonization factors.
Conclusions/Significance: The genomic inventories of genetically related S. suis strains, isolated from distinct hosts and
diseases, exhibit high levels of conservation. However, the genomes provide evidence that horizontal gene transfer has
contributed to the evolution of drug resistance
Hyper-acute cardiovascular magnetic resonance T1 mapping predicts infarct characteristics in patients with ST elevation myocardial infarction
Background
Myocardial recovery after primary percutaneous coronary intervention in acute myocardial infarction is variable and the extent and severity of injury are difficult to predict. We sought to investigate the role of cardiovascular magnetic resonance T1 mapping in the determination of myocardial injury very early after treatment of ST-segment elevation myocardial infarction (STEMI).
Methods
STEMI patients underwent 3 T cardiovascular magnetic resonance (CMR), within 3 h of primary percutaneous intervention (PPCI). T1 mapping determined the extent (area-at-risk as %left ventricle, AAR) and severity (average T1 values of AAR) of acute myocardial injury, and related these to late gadolinium enhancement (LGE), and microvascular obstruction (MVO). The characteristics of myocardial injury within 3 h was compared with changes at 24-h to predict final infarct size.
Results
Forty patients were included in this study. Patients with average T1 values of AAR ≥1400 ms within 3 h of PPCI had larger LGE at 24-h (33% ±14 vs. 18% ±10, P = 0.003) and at 6-months (27% ±9 vs. 12% ±9; P 9.5%) with 100% positive predictive value at the optimal cut-off of 1400 ms (area-under-the-curve, AUC 0.88, P = 0.006).
Conclusion
Hyper-acute T1 values of the AAR (within 3 h post PPCI, but not 24 h) predict a larger extent of MVO and infarct size at both 24 h and 6 months follow-up. Delayed CMR scanning for 24 h could not substitute the significant value of hyper-acute average T1 in determining infarct characteristics
Intranasal H5N1 vaccines, adjuvanted with chitosan derivatives, protect ferrets against highly pathogenic influenza intranasal and intratracheal challenge
We investigated the protective efficacy of two intranasal chitosan (CSN and TM-CSN) adjuvanted H5N1 Influenza vaccines against highly pathogenic avian Influenza (HPAI) intratracheal and intranasal challenge in a ferret model. Six groups of 6 ferrets were intranasally vaccinated twice, 21 days apart, with either placebo, antigen alone, CSN adjuvanted antigen, or TM-CSN adjuvanted antigen. Homologous and intra-subtypic antibody cross-reacting responses were assessed. Ferrets were inoculated intratracheally (all treatments) or intranasally (CSN adjuvanted and placebo treatments only) with clade 1 HPAI A/Vietnam/1194/2004 (H5N1) virus 28 days after the second vaccination and subsequently monitored for morbidity and mortality outcomes. Clinical signs were assessed and nasal as well as throat swabs were taken daily for virology. Samples of lung tissue, nasal turbinates, brain, and olfactory bulb were analysed for the presence of virus and examined for histolopathological findings. In contrast to animals vaccinated with antigen alone, the CSN and TM-CSN adjuvanted vaccines induced high levels of antibodies, protected ferrets from death, reduced viral replication and abrogated disease after intratracheal challenge, and in the case of CSN after intranasal challenge. In particular, the TM-CSN adjuvanted vaccine was highly effective at eliciting protective immunity from intratrache
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