18,191 research outputs found

    Rotational and hyperfine analysis of the near infrared 3Φ4-X3Φ4 transitions of CoCl and Col

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    A rotational and hyperfine analysis of the 3φ 4- 3φ 4 transition of CoCl and CoI in the near infrared region was reported. Six and eight vibronic transition band soft CoCl and CoI, respectively, were recorded and analyzed. Accurate molecular parameters for both the upper and the ground 3φ 4 states were determined by least squares fitting of line positions of observed bands simultaneously for each molecule, which yielded accurate molecular parameters for both the upper and lower 3φ 4 states.published_or_final_versio

    Circulating leukocyte telomere length is highly heritable among families of Arab descent

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    Background Telomere length, an indicator of ageing and longevity, has been correlated with several biomarkers of cardiometabolic disease in both Arab children and adults. It is not known, however, whether or not telomere length is a highly conserved inheritable trait in this homogeneous cohort, where age-related diseases are highly prevalent. As such, the aim of this study was to address the inheritability of telomere length in Saudi families and the impact of cardiometabolic disease biomarkers on telomere length. Methods A total of 119 randomly selected Saudi families (123 adults and 131 children) were included in this cross-sectional study. Anthropometrics were obtained and fasting blood samples were taken for routine analyses of fasting glucose and lipid profile. Leukocyte telomere length was determined using quantitative real time PCR. Results Telomere length was highly heritable as assessed by a parent-offspring regression [h2 = 0.64 (p = 0.0006)]. Telomere length was modestly associated with BMI (R2 0.07; p-value 0.0087), total cholesterol (R2 0.08; p-value 0.0033), and LDL-cholesterol (R2 0.15; p-value 3 x 10-5) after adjustments for gender, age and age within generation. Conclusion The high heritability of telomere length in Arab families, and the associations of telomere length with various cardiometabolic parameters suggest heritable genetic fetal and/or epigenetic influences on the early predisposition of Arab children to age-related diseases and accelerated ageing

    Student Perception of a Visual Novel for Fostering Science Process Skills

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    In undergraduate science education, emphasis is often placed on teaching subject matter rather than science process skills (e.g., critical thinking, problem solving). Although important to scientific training, these skills are often not taught because science educators do not feel equipped to teach them. We therefore present a case-scenario activity that aims to facilitate the development of science process skills. This activity, which takes the form of a visual novel, asks students to generate hypotheses for the seemingly odd events that are described in the story. We implemented this activity in a science-process-focused course. Upon completion of the activity, we asked students to submit a written response to the prompt: “What are you taking away from the activity?” In this exploratory study, we conducted a qualitative analysis of these written responses to ascertain whether meaningful codes and themes related to science process would arise from this open-ended prompt. Based on student responses, four main themes emerged: scientific inquiry, student satisfaction, flexibility, and collaboration. These results demonstrated the activity was both enjoyable, and it successfully enabled students to apply science process skills. We offer this activity in anticipation it will provide educators with a tool to include these skills in their classes

    Is fundamental frequency a cue to aspiration in initial stops?

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    One production and one perception experiment were conducted to investigate the interaction of consonant voicing and fundamental frequency at the onset of voicing (onset f0) in Cantonese, a tonal language. Consonantal voicing in English can affect onset f0 up to 100 ms after voicing onset, but existing research provides inconclusive information regarding the effects of voicing on f0 in tonal languages where f0 variability is constrained by the demands of the lexical tone system. Previous research on consonantal effects on onset f0 provides two contrasting theories: These effects may be automatic, resulting from physiological constraints inherent to the speech production mechanism or they may be controlled, produced as part of a process of cue enhancement for the perception of laryngeal contrasts. Results of experiment 1 showed that consonant aspiration affects onset f0 in Cantonese only within the first 10 ms following voicing onset, comparable to results for other tonal languages. Experiment 2 showed that Cantonese listeners can use differences in onset f0 to cue perception of the voicing contrast, but the minimum extent of f0 perturbation necessary for this is greater than is found in Cantonese production, and comparable to that observed in acoustic studies of nontonal languages. These results suggest that consonantal effects on onset f0 are at least partially controlled by talkers, but that their role in the perception of voicing/aspiration may be a consequence of language independent properties of audition rather than listeners' experience with the phonological contrasts of a specific language.published_or_final_versio

    The perception of Cantonese lexical tones by early-deafened cochlear implantees

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    This study investigated whether cochlear implant users can identify Cantonese lexical tones, which differ primarily in their FO pattern. Seventeen early-deafened deaf children (age=4 years, 6 months to 8 years, 11 months; postoperative period = 11 - 41 months) took part in the study. Sixteen children were fitted with the Nucleus 24 cochlear implant system; one child was fitted with a Nucleus 22 implant. Participants completed a 2AFC picture identification task in which they identified one of the six contrastive Cantonese tones produced on the monosyllabic target word /ji/. Each target stimulus represented a concrete object and was presented within a carrier phrase in sentence-medial position. Group performance was significantly above chance for three contrasts. However, the cochlear implant listeners performed much worse than a 6 1/2-year-old, moderately hearing impaired control listener who was tested on the same task. These findings suggest that this group of cochlear implant users had great difficulty in extracting the pitch information needed to accurately identify Cantonese lexical tones. © 2002 Acoustical Society of America.published_or_final_versio

    Evaluation of Bioactivities and Phenolic Content of Selected Edible Mushrooms in Malaysia

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    Purpose: To determine the radical scavenging, metal chelating, antibacterial and cytotoxic activities of five edible mushrooms in Malaysia.Methods: Mushrooms (H. tessulatus, P. eryngii, P. florida, A. polytricha and F. velutipes) were ovendried and extracted with 90 % ethanol. Radical scavenging and metal chelating assays were based on the measurement of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferrozine absorbance at 517 and 562 nm, respectively. Mushrooms total phenolic and flavonoid contents were determined by spectrophotometric methods. Antimicrobial activity was measured using Kirby-Bauer Susceptibility Test. Cytotoxicity was assessed using brine shrimp toxicity assay.Results: Total phenolic and flavonoid contents ranged from 0.90 - 6.03 mg GAE per g of dry sample and 0.17 - 6.95 mg QE per g of dry sample, respectively. A. polytricha demonstrated the strongest radical scavenging and metal chelating activities. Moderate antimicrobial activity was found for extracts of both P. florida and A. polytricha. Cytotoxicity LD50 ranged from 46.9 - 115.8 μg/ml.Conclusion: The results suggest that A. polytricha is a suitable candidate for chemoprevention and would safe for use in large doses.Keywords: Cytotoxicity, Flavonoid, Free radical scavenging, Metal chelating, Mushroom, Phenoli

    The association of long-term exposure to criteria air pollutants, fine particulate matter components, and airborne trace metals with late-life brain amyloid burden in the Atherosclerosis Risk in Communities (ARIC) study

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    BACKGROUND: Studies suggest associations between long-term ambient air pollution exposure and outcomes related to Alzheimer\u27s disease (AD). Whether a link exists between pollutants and brain amyloid accumulation, a biomarker of AD, is unclear. We assessed whether long-term air pollutant exposures are associated with late-life brain amyloid deposition in Atherosclerosis Risk in Communities (ARIC) study participants. METHODS: We used a chemical transport model with data fusion to estimate ambient concentrations of PM RESULTS: At PET imaging, eligible participants (N = 318) had a mean age of 78 years, 56% were female, 43% were Black, and 27% had mild cognitive impairment. We did not find evidence of associations between long-term exposure to any pollutant and brain amyloid positivity in adjusted models. Findings were materially unchanged in sensitivity analyses using alternate air pollution estimation approaches for PM CONCLUSIONS: Air pollution may impact cognition and dementia independent of amyloid accumulation, though whether air pollution influences AD pathogenesis later in the disease course or at higher exposure levels deserves further consideration
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