21 research outputs found

    On the Application of a Monolithic Array for Detecting Intensity-Correlated Photons Emitted by Different Source Types

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    It is not widely appreciated that many subtleties are involved in the accurate measurement of intensity-correlated photons; even for the original experiments of Hanbury Brown and Twiss (HBT). Using a monolithic 4x4 array of single-photon avalanche diodes (SPADs), together with an off-chip algorithm for processing streaming data, we investigate the difficulties of measuring second-order photon correlations g2 in a wide variety of light fields that exhibit dramatically different correlation statistics: a multimode He-Ne laser, an incoherent intensity-modulated lamp-light source and a thermal light source. Our off-chip algorithm treats multiple photon-arrivals at pixel-array pairs, in any observation interval, with photon fluxes limited by detector saturation, in such a way that a correctly normalized g2 function is guaranteed. The impact of detector background correlations between SPAD pixels and afterpulsing effects on second-order coherence measurements is discussed. These results demonstrate that our monolithic SPAD array enables access to effects that are otherwise impossible to measure with stand-alone detectors.Comment: 17 pages, 6 figure

    Fortified breakfast cereal consumed daily for 12 wk leads to a significant improvement in micronutrient intake and micronutrient status in adolescent girls: a randomised controlled trial

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    Background: Poor micronutrient status is reported among adolescents across Europe and USA. This may be related to the well-documented decline in the regular consumption of breakfast by this group. The regular consumption of a breakfast cereal offers a possible means to improve micronutrient status; fortified cereal is likely to have enhanced benefit. A study was conducted to determine the efficacy of the regular consumption of a fortified cereal with milk, compared with unfortified cereal, consumed either as a breakfast or a supper, in improving micronutrient intake and micronutrient status of adolescent girls. Methods: A randomised, double-blind, placebo-controlled intervention trial was conducted in girls recruited at ages 16–19 years, from schools and colleges in Sheffield, UK. Girls were randomised to receive 50 g fortified or unfortified cereal, with 150 ml semi-skimmed milk, daily, for 12 weeks, as a breakfast or as a supper. Dietary intake was estimated using a 4-d food diary and blood collected for the assessment of nutritional status. Within-group changes were tested using a paired sample t test; two-way ANOVA was used to analyse effects of the intervention, with cereal type and time of consumption as factors, correcting for baseline values. The analysis was conducted on 71 girls who completed the study. Results: Consumption of unfortified cereal elicited an increase in the intake of vitamins B1, B2 and B6; consumption of fortified cereal elicited increases in vitamins B1, B2, B6, B12, folate and iron (P < 0.001) and of vitamin D (P = 0.007), all increases were significantly greater than for unfortified cereal. Consumption of the fortified cereal also led to a significant improvement in biomarkers of status for vitamins B2, B12, folate and of iron, compared with girls receiving the unfortified cereal, and maintained vitamin D status, in contrast with the girls receiving the unfortified cereal (P < 0.001). Conclusions: The daily consumption of cereal with milk for 12 weeks by adolescent girls, increased intakes of micronutrients. The consumption of fortified cereal elicited greater increases than for unfortified cereal and improved biomarkers of micronutrient status. The findings justify strategies to encourage the consumption of fortified cereal with milk by adolescents, either as a breakfast or a supper

    Applying an extended theory of planned behaviour to predict breakfast consumption in adolescents

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    BACKGROUND/OBJECTIVES: Breakfast skipping increases during adolescence and is associated with lower levels of physical activity and weight gain. Theory-based interventions promoting breakfast consumption in adolescents report mixed findings, potentially because of limited research identifying which determinants to target. This study aimed to: (i) utilise the Theory of Planned Behaviour (TPB) to identify the relative contribution of attitudes (affective, cognitive and behavioural) to predict intention to eat breakfast and breakfast consumption in adolescents and (ii) determine whether demographic factors moderate the relationship between TPB variables, intention and behaviour. SUBJECTS/METHODS: Questionnaires were completed by 434 students (mean 14+/-0.9 years) measuring breakfast consumption (0-2, 3-6 or 7 days), physical activity levels and TPB measures. Data were analysed by breakfast frequency and demographics using hierarchical and multinomial regression analyses. RESULTS: Breakfast was consumed everyday by 57% of students, with boys more likely to eat a regular breakfast, report higher activity levels and report more positive attitudes towards breakfast than girls (P<0.001). The TPB predicted 58% of the variation in intentions. Overall, the model was predictive of breakfast behaviours (P<0.001), but the relative contribution of TPB constructs varied depending on breakfast frequency. Interactions between gender and intentions were significant when comparing 0-2- and 3-6-day breakfast eaters only highlighting a stronger intention-behaviour relationship for girls. CONCLUSIONS: Findings confirm that the TPB is a successful model for predicting breakfast intentions and behaviours in adolescents. The potential for a direct effect of attitudes on behaviours should be considered in the implementation and design of breakfast interventions

    Pooled analysis of who surgical safety checklist use and mortality after emergency laparotomy

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    Background: The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods: In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results: Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89⋅6 per cent) compared with that in countries with a middle (753 of 1242, 60⋅6 per cent; odds ratio (OR) 0⋅17, 95 per cent c.i. 0⋅14 to 0⋅21, P &lt; 0⋅001) or low (363 of 860, 42⋅2 percent; OR 0⋅08, 0⋅07 to 0⋅10, P &lt; 0⋅001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference −9⋅4 (95 per cent c.i. −11⋅9 to −6⋅9) per cent; P &lt; 0⋅001), but the relationship was reversed in low-HDI countries (+12⋅1 (+7⋅0 to +17⋅3) per cent; P &lt; 0⋅001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0⋅60, 0⋅50 to 0⋅73; P &lt; 0⋅001). The greatest absolute benefit was seen for emergency surgery in low-and middle-HDI countries. Conclusion: Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries

    Intraspecific genetic variation of striped red mullet (Mullus surmuletus L.) in the Mediterranean Sea assessed by allozyme and random amplified polymorphic DNA (RAPD) analysis

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    Allozyme analysis on 20 putative enzyme-coding loci and RAPD analysis on 154 markers, amplified by eight decamer random primers, were used to assess the genetic variation of striped red mullet, Mullus surmuletus L., collected from six locations in the Mediterranean Sea. Both methods were able to detect a high degree of genetic polymorphism. For both methods, estimates of variance of allele frequencies (F-ST), and chi(2) analyses, revealed significant differences (P < 0.05) among samples. Nei's genetic distance (D) among samples was low (mean D = 0.011 for allozymes; mean D = 0.018 for RAPDs) with data from both approaches revealing the sample from France to be most distinct from the Greek samples. Nevertheless, although most of the genetic variation in allozymes was not correlated with geographical distance, a correlation between genetic affinities and geographical area was found with RAPDs. It seems therefore that the RAPD method showed a more pronounced effect of isolation-by-distance in comparison with allozymes, probably because of the different number of markers of the red mullet genome examined with each method. Overall, the RAPD technique can be introduced as a complementary tool in the population genetics of marine fishes, providing supplementary information in their genetic stock structure analysis

    No breakfast at home: association with cardiovascular disease risk factors in childhood

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    BACKGROUND/OBJECTIVES: Limited data exist regarding breakfast consumption and its association with cardiovascular disease (CVD) risk factors. This study investigates the relationship between breakfast routine and CVD risk factors in a multinational sample. SUBJECTS/METHODS: Cross-sectional data from eight European countries participating in the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) survey (2007-2008) were used. The sample included children 2 to <10 years of age (n=8863, 51.2% boys). The Mann-Whitney U-test and logistic regression were used to assess CVD risk factors among no breakfast (NBrH), occasional breakfast and daily breakfast at home (DBrH) consumption. RESULTS: Male school-aged NBrH consumers, compared with DBrH consumers, were more likely to be overweight/obese (odds ratio (OR): 1.37, 95% confidence interval (Cl) = 1.05-1.79), to have higher risk for high-density lipoprotein (HDL) cholesterol levels lower than 40 mg/dl (OR: 1.69, 95% CI = 1.24-2.30), triglycerides (TG) above 75 mg/dl (OR: 1.65, 95% CI = 1.24-2.19) and sum of skinfolds greater than the 90th percentile (OR: 1.32, 95% CI = 1.0-1.76). Female school-aged NBrH consumers compared with DBrH consumers had a higher risk for waist circumference greater than the 90th percentile (OR: 1.70, 95% CI = 1.14-2.51), HDL cholesterol levels lower than 40 mg/dl (OR: 1.65, 95% CI = 1.23-2.21), TG above 75 mg/dl (OR: 1.65, 95% CI = 1.26-2.17) and total cholesterol/HDL cholesterol ratio >3.5 (OR: 1.39, 95% CI = 1.09-1.77). Results remained significant after adjusting for daily physical activity in moderate-to-vigorous physical activity (MVPA) periods (in min/day). Male DBrH consumers, 6 to <10 years of age, had longer daily periods of MVPA compared with NBrH consumers (32.0 +/- 21.4 vs 27.5 +/- 18.8, P < 0.05). For preschoolers, breakfast consumption was negatively associated with CVD risk factors but results of regression models were mostly insignificant. CONCLUSIONS: Daily breakfast consumption contributes to controlling school-aged children's weight and lipid profile and promotes higher PA

    Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players

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    Background To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d−1 during 14 d) on muscle power output in elite youth soccer players. Methods Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. Results There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period. Conclusion There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players
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