314 research outputs found

    Maximizing the effect of visual feedback for pronunciation instruction: A comparative analysis of three approaches

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    Visual feedback, in which learners visually analyze acoustic speech characteristics, has been shown to significantly improve pronunciation, but extant research has varied widely with respect to the target feature, length of the intervention, and type of intervention. This study presents a comparative analysis of three methods of visual feedback for L2 segmental pronunciation instruction. These methods, all focused on training voice onset time for English-speaking learners of Spanish, differed in duration of instruction (i.e., short and long) and the nature of each intervention (i.e., phonemes presented simultaneously or sequentially). Results show that while all forms of visual feedback significantly improve L2 Spanish pronunciation, evidenced by a reduction in voice onset time, the greatest improvement was found following both longer treatments and a sequential approach. Theoretical and pedagogical implications are discussed

    Seascape Genetics: A Coupled Oceanographic-Genetic Model Predicts Population Structure of Caribbean Corals

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    SummaryPopulation genetics is a powerful tool for measuring important larval connections between marine populations [1–4]. Similarly, oceanographic models based on environmental data can simulate particle movements in ocean currents and make quantitative estimates of larval connections between populations possible [5–9]. However, these two powerful approaches have remained disconnected because no general models currently provide a means of directly comparing dispersal predictions with empirical genetic data (except, see [10]). In addition, previous genetic models have considered relatively simple dispersal scenarios that are often unrealistic for marine larvae [11–15], and recent landscape genetic models have yet to be applied in a marine context [16–20]. We have developed a genetic model that uses connectivity estimates from oceanographic models to predict genetic patterns resulting from larval dispersal in a Caribbean coral. We then compare the predictions to empirical data for threatened staghorn corals. Our coupled oceanographic-genetic model predicts many of the patterns observed in this and other empirical datasets; such patterns include the isolation of the Bahamas and an east-west divergence near Puerto Rico [3, 21–23]. This new approach provides both a valuable tool for predicting genetic structure in marine populations and a means of explicitly testing these predictions with empirical data (Figure 1)

    Health and Financial Fragility: Evidence from Car Crashes and Consumer Bankruptcy

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    This paper assesses the importance of adverse health shocks as triggers of bankruptcy filings. We view car crashes as a proxy for health shocks and draw on a large sample of police crash reports linked to hospital admission records and bankruptcy case files. We report two findings: (i) there is a strong positive correlation between an individual\u27s pre-shock financial condition and his or her likelihood of suffering a health shock, an example of behavioral consistency; and (ii) after accounting for this simultaneity, we are unable to identify a causal effect of health shocks on bankruptcy filing rates. These findings emphasize the importance of risk heterogeneity in determining financial fragility, raise questions about prior studies of medical bankruptcy, and point to important challenges in identifying the triggers of consumer bankruptcy

    Safety and efficacy of ganaxolone in patients with CDKL5 deficiency disorder: results from the double-blind phase of a randomised, placebo-controlled, phase 3 trial

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    BACKGROUND: CDKL5 deficiency disorder (CDD) is a rare, X-linked, developmental and epileptic encephalopathy characterised by severe global developmental impairment and seizures that can begin in the first few months after birth and are often treatment refractory. Ganaxolone, an investigational neuroactive steroid, reduced seizure frequency in an open-label, phase 2 trial that included patients with CDD. We aimed to further assess the efficacy and safety of ganaxolone in patients with CDD-associated refractory epilepsy. METHODS: In the double-blind phase of this randomised, placebo-controlled, phase 3 trial, done at 39 outpatient clinics in eight countries (Australia, France, Israel, Italy, Poland, Russia, the UK, and the USA), patients were eligible if they were aged 2-21 years with a pathogenic or probably pathogenic CDKL5 variant and at least 16 major motor seizures (defined as bilateral tonic, generalised tonic-clonic, bilateral clonic, atonic, or focal to bilateral tonic-clonic) per 28 days in each 4-week period of an 8-week historical period. After a 6-week prospective baseline period, patients were randomly assigned (1:1) via an interactive web response system to receive either enteral adjunctive ganaxolone or matching enteral adjunctive placebo (maximum dose 63 mg/kg per day for patients weighing ≤28 kg or 1800 mg/day for patients weighing >28 kg) for 17 weeks. Patients, caregivers, investigators (including those analysing data), trial staff, and the sponsor (other than the investigational product manager) were masked to treatment allocation. The primary efficacy endpoint was percentage change in median 28-day major motor seizure frequency from the baseline period to the 17-week double-blind phase and was analysed (using a Wilcoxon-rank sum test) in all patients who received at least one dose of trial treatment and for whom baseline data were available. Safety (compared descriptively across groups) was analysed in all patients who received at least one dose of trial treatment. This study is registered with ClinicalTrials.gov, NCT03572933, and the open-label extension phase is ongoing. FINDINGS: Between June 25, 2018, and July 2, 2020, 114 patients were screened for eligibility, of whom 101 (median age 6 years [IQR 3 to 10]) were randomly assigned to receive either ganaxolone (n=50) or placebo (n=51). All patients received at least one dose of a study drug, but seizure frequency for one patient in the ganaxolone group was not recorded at baseline and so the primary endpoint was analysed in a population of 100 patients. There was a median percentage change in 28-day major motor seizure frequency of -30·7% (IQR -49·5 to -1·9) in the ganaxolone group and of -6·9% (-24·1 to 39·7) in the placebo group (p=0·0036). The Hodges-Lehmann estimate of median difference in responses to ganaxolone versus placebo was -27·1% (95% CI -47·9 to - 9·6). Treatment-emergent adverse events occurred in 43 (86%) of 50 patients in the ganaxolone group and in 45 (88%) of 51 patients in the placebo group. Somnolence, pyrexia, and upper respiratory tract infections occurred in at least 10% of patients in the ganaxolone group and more frequently than in the placebo group. Serious adverse events occurred in six (12%) patients in the ganaxolone group and in five (10%) patients in the placebo group. Two (4%) patients in the ganaxolone group and four (8%) patients in the placebo group discontinued the trial. There were no deaths in the double-blind phase. INTERPRETATION: Ganaxolone significantly reduced the frequency of CDD-associated seizures compared with placebo and was generally well tolerated. Results from what is, to our knowledge, the first controlled trial in CDD suggest a potential treatment benefit for ganaxolone. Long-term treatment is being assessed in the ongoing open-label extension phase of this trial. FUNDING: Marinus Pharmaceuticals

    Screening for UGT1A1 Genotype in Study A5257 Would Have Markedly Reduced Premature Discontinuation of Atazanavir for Hyperbilirubinemia

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    Background. Some patients are not prescribed atazanavir because of concern about possible jaundice. Atazanavir-associated hyperbilirubinemia correlates with UGT1A1 rs887829 genotype. We examined bilirubin-related discontinuation of atazanavir in participants from AIDS Clinical Trials Group Study A5257. Methods. Discriminatory properties of UGT1A1 T/T genotype for predicting bilirubin-related atazanavir discontinuation through 96 weeks after antiretroviral initiation were estimated. Results. Genetic analyses involved 1450 participants, including 481 who initiated randomized atazanavir/ritonavir. Positive predictive values of rs887829 T/T for bilirubin-related discontinuation of atazanavir (with 95% confidence intervals [CIs]) were 20% (CI, 9%–36%) in Black, 60% (CI, 32%–84%) in White, and 29% (CI, 8%–58%) in Hispanic participants; negative predictive values were 97% (CI, 93%–99%), 95% (CI, 90%–98%), and 97% (CI, 90%–100%), respectively. Conclusions. Bilirubin-related discontinuation of atazanavir was rare in participants not homozygous for rs887829 T/T, regardless of race or ethnicity. We hypothesize that the higher rate of discontinuation among White participants homozygous for rs887829 T/T may reflect differences in physical manifestations of jaundice by race and ethnicity. Selective avoidance of atazanavir initiation among individuals with T/T genotypes would markedly reduce the likelihood of bilirubin-related discontinuation of atazanavir while allowing atazanavir to be prescribed to the majority of individuals. This genetic association will also affect atazanavir/cobicistat

    Accumulation of Succinyl Coenzyme A Perturbs the Methicillin-Resistant Staphylococcus aureus (MRSA) Succinylome and Is Associated with Increased Susceptibility to Beta-Lactam Antibiotics

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    Penicillin binding protein 2a (PBP2a)-dependent resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is regulated by the activity of the tricarboxylic acid (TCA) cycle via a poorly understood mechanism. We report that mutations in sucC and sucD, but not other TCA cycle enzymes, negatively impact β-lactam resistance without changing PBP2a expression. Increased intracellular levels of succinyl coenzyme A (succinyl-CoA) in the sucC mutant significantly perturbed lysine succinylation in the MRSA proteome. Suppressor mutations in sucA or sucB, responsible for succinyl-CoA biosynthesis, reversed sucC mutant phenotypes. The major autolysin (Atl) was the most succinylated protein in the proteome, and increased Atl succinylation in the sucC mutant was associated with loss of autolytic activity. Although PBP2a and PBP2 were also among the most succinylated proteins in the MRSA proteome, peptidoglycan architecture and cross-linking were unchanged in the sucC mutant. These data reveal that perturbation of the MRSA succinylome impacts two interconnected cell wall phenotypes, leading to repression of autolytic activity and increased susceptibility to β-lactam antibiotics. IMPORTANCE mecA-dependent methicillin resistance in MRSA is subject to regulation by numerous accessory factors involved in cell wall biosynthesis, nucleotide signaling, and central metabolism. Here, we report that mutations in the TCA cycle gene, sucC, increased susceptibility to β-lactam antibiotics and was accompanied by significant accumulation of succinyl-CoA, which in turn perturbed lysine succinylation in the proteome. Although cell wall structure and cross-linking were unchanged, significantly increased succinylation of the major autolysin Atl, which was the most succinylated protein in the proteome, was accompanied by near complete repression of autolytic activity. These findings link central metabolism and levels of succinyl-CoA to the regulation of β-lactam antibiotic resistance in MRSA through succinylome-mediated control of two interlinked cell wall phenotypes. Drug-mediated interference of the SucCD-controlled succinylome may help overcome β-lactam resistance
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