241 research outputs found

    Collective Two-Atom Effects and Trapping States in the Micromaser

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    We investigate signals of trapping states in the micromaser system in terms of the average number of cavity photons as well as a suitably defined correlation length of atoms leaving the cavity. In the description of collective two-atom effects we allow the mean number of pump atoms inside the cavity during the characteristic atomic cavity transit time to be as large as of order one. The master equation we consider, which describes the micromaser including collective two-atom effects, still exhibits trapping states for even for a mean number of atoms inside the cavity close to one. We, however, argue more importantly that the trapping states are more pronounced in terms of the correlation length as compared to the average number of cavity photons, i.e. we suggest that trapping states can be more clearly revealed experimentally in terms of the atom correlation length. For axion detection in the micromaser this observable may therefore be an essential ingredient.Comment: 5 figure

    Anomalous Scaling and Solitary Waves in Systems with Non-Linear Diffusion

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    We study a non-linear convective-diffusive equation, local in space and time, which has its background in the dynamics of the thickness of a wetting film. The presence of a non-linear diffusion predicts the existence of fronts as well as shock fronts. Despite the absence of memory effects, solutions in the case of pure non-linear diffusion exhibit an anomalous sub-diffusive scaling. Due to a balance between non-linear diffusion and convection we, in particular, show that solitary waves appear. For large times they merge into a single solitary wave exhibiting a topological stability. Even though our results concern a specific equation, numerical simulations supports the view that anomalous diffusion and the solitary waves disclosed will be general features in such non-linear convective-diffusive dynamics.Comment: Corrected typos, added 3 references and 2 figure

    Genetics and Responsibility: To Know the Criminal From the Crime

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    The use of the t6O(o,o)160 elastic scattering resonance reaction forthe study of low concentration of oxygen such as found in interfacesin silicon technology is described. We have investigated the depth resolution and the limit of the sensitivity that can be obtained with thismethod. The method has been applied to the study of AlrQ{r "sandwich" film structures and to Au and amorphous Ge contacts to silicon

    Generalized Phase Space Representation of Operators

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    Introducing asymmetry into the Weyl representation of operators leads to a variety of phase space representations and new symbols. Specific generalizations of the Husimi and the Glauber-Sudarshan symbols are explicitly derivedComment: latex, 8 pages, expanded version accepted by J. Phys.

    Early postnatal nutrition after preterm birth and cardiometabolic risk factors in young adulthood

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    Objectives Adults born preterm at very low birthweight (VLBW; Study design The Helsinki Study of VLBW Adults includes 166 VLBW and preterm infants born between 1978 and 1985. We collected postnatal nutrition data among 125 unimpaired subjects, who attended two study visits at the mean ages of 22.5 and 25.1 years. We evaluated the effects of energy and macronutrient intakes during the first three 3-week periods of life on key cardiometabolic risk factors with multiple linear regression models. We also report results adjusted for prenatal, postnatal and adult characteristics. Results Macronutrient and energy intakes were not associated with blood pressure, heart rate, or lipid levels in adulthood. Intakes were neither associated with fasting glucose or most other markers of glucose metabolism. An exception was that the first-three-weeks-of-life intakes predicted higher fasting insulin levels: 1 g/kg/day higher protein intake by 37.6% (95% CI: 8.0%, 75.2%), and 10 kcal/kg/day higher energy intake by 8.6% (2.6%, 14.9%), when adjusted for sex and age. These early intakes similarly predicted the adult homeostasis model assessment index. Further adjustments strengthened these findings. Conclusions Among VLBW infants with relatively low early energy intake, early macronutrient and energy intakes were unrelated to blood pressure, lipid levels and intravenous glucose tolerance test results. Contrary to our hypothesis, a higher macronutrient intake during the first three weeks of life predicted higher fasting insulin concentration in young adulthood.Peer reviewe

    Polygenic Risk Score of SERPINA6/SERPINA1 Associates with Diurnal and Stress-Induced HPA Axis Activity in Children

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    Purpose: Corticosteroid-binding globulin (CBG) transports glucocorticoids in blood. Variation in genes SERPINA6 encoding for CBG, SERPINA2 and SERPINAI (serpin family A member 6, 2, and 1) have been shown to influence morning plasma cortisol and CBG in adults. However, association of this genetic variation with diurnal and stress-induced salivary cortisol remain unknown. This study aims to investigate the effect of genetic variation in SERPINA6/2/1 loci on diurnal and stress-induced salivary cortisol in children. Methods: We studied 186, 8-year-old children with genome-wide genotyping. We generated weighted polygenic risk score (PRS) based on 6 genome-wide significant SNPs (rs11621961, rs11629171, rs7161521, rs2749527, rs3762132, rs4900229) derived from the CORNET meta-analyses. Salivary cortisol was measured across one day and in response to the Trier Social Stress Test for Children (TSST-C). Results: Mixed models, adjusted for covariates, showed that the PRS x sampling time interactions associated with diurnal (P <0.001) and stress-induced (P = 0.009) salivary cortisol. In the high PRS group (dichotomized at median) the diurnal salivary cortisol pattern decreased less from awakening to bedtime than in the low PRS group (standardized estimates of sampling time -0.64 vs. -0.73, P <0.0001 for both estimates). In response to stress, salivary cortisol increased in the high PRS group while it remained unchanged in the low PRS group (standardized estimates of sampling time 0.12, P = 0.015 vs. -0.06, P = 0.16). These results were mainly driven by minor alleles of rs7161521 (SERPINA6) and rs4900229 (SERPINAI). Conclusions: Genetic variation in SERPINA6/2/1loci may underpin higher hypothalamic-pituitary-adrenocortical axis activity in children.Peer reviewe

    Neurocognitive outcome in young adults born late-preterm

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    Aim This study examined whether late-preterm birth (34+0 to 36+6wks+d gestational age) was associated with neurocognitive deficit in young adulthood, and whether small for gestational age (SGA) birth amplified any adversity. Method Participants derived from the prospective regional cohort study, the Arvo Ylppö Longitudinal Study (n=786; 398 females, 388 males) (mean age 25y 4mo, SD 8mo), born 1985 to 1986 late-preterm (n=119; 21 SGA, <−2 SD) and at term (37+0 to 41+6wks+d; n=667; 28 SGA) underwent tests of intelligence, executive functioning, attention, and memory, and reported their education. Results Those born late-preterm scored −3.71 (95% confidence interval [CI] −6.71 to −0.72) and −3.11 (95% CI −6.01 to −0.22) points lower on Full-scale and Verbal IQ than peers born at term. Compared with those born at term and appropriate for gestational age (≥−2 to <2 SD) Full-scale, Verbal, and Performance IQ scores of those born late-preterm and SGA were −9.45 to −11.84 points lower. After adjustments, differences were rendered non-significant, except that scores in Full-scale and Performance IQ remained lower among those born late-preterm and SGA. Interpretation Late-preterm birth, per se, may not increase the risk of poorer neurocognitive functioning in adulthood. But the double burden of being born late-preterm and SGA seems to increase this risk

    Childhood cognitive ability and physical activity in young adulthood

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    Objective: Childhood cognitive ability is associated with lifestyle in adulthood, including self-reported physical activity (PA). We examined whether childhood cognitive ability is associated with objectively-measured PA and sedentary time (ST) in young adulthood. Methods: Participants of the Arvo Ylppö Longitudinal Study (n=500) underwent tests of general reasoning, visuo-motor integration, verbal competence and language comprehension at the age of 56 months yielding a general intelligence factor score; at the age of 25 years they wore omnidirectional accelerometers for 9 days (Range=4-10 days) measuring overall daily PA (counts per minute, cpm), ST and light and moderate-to-vigorous PA (MVPA) (minutes), and completed a questionnaire on occupational, commuting, leisure-time conditioning and non-conditioning PA. Results: After adjustment for sex, age, BMI-for-age SD score at 56 months and mean of valid minutes of measurement period for PA, per each one SD increase in the childhood general intelligence factor score, overall daily PA decreased by -8.99 CPM/day, ST increased by 14.93 minutes/day, time spent in light PA decreased by -14.39 minutes/day, and the odds per each level increase in physical demandingness of the work and in time spent in non-conditioning leisure-time PA decreased by 38% and 31%, respectively (p-values<0.04). These associations were mediated via higher young adulthood level of education. Conclusions: In contrast to expected, in this cohort of young adults with high variability in PA, of whom many were still studying, higher childhood cognitive ability was associated with more objectively-measured and self-reported physical inactivity. Whether these findings persist beyond young adulthood is a subject of further studies

    Maternal early pregnancy body mass index and diurnal salivary cortisol in young adult offspring

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    Background Maternal early pregnancy overweight (body mass index [BMI] 25.0-29.9 kg/m(2)) and obesity (BMI >= 30 kg/m(2)) are associated with mental and physical health adversities in the offspring. Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis has been put forward as one of the mechanisms that may play pathophysiological role. However, evidence linking maternal overweight and obesity with offspring HPA-axis activity is scarce. We studied if maternal early pregnancy BMI is associated with diurnal salivary cortisol, a marker of HPA-axis activity, in young adult offspring. Methods At a mean age of 25.3 (standard deviation [SD) = 0.6) years, 653 Arvo Ylppo Longitudinal Study participants collected saliva samples for cortisol analyses, at awakening, 15 and 30 min thereafter, 10:30AM, 12:00PM, 5:30PM and at bedtime. Maternal BMI was calculated from weight and height verified by a measurement in the first antenatal clinic visit before 12 weeks of gestation derived from healthcare records. Results Per each one kg/m(2) higher maternal early pregnancy BMI offspring diurnal average salivary cortisol was -1.4% (95% CI:-2.6, -0.2, p(FDR) = 0.033) lower, at awakening it was -2.4% (95% CI:-4.0, -0.7, p(FDR) = 0.025) lower and the morning average salivary cortisol was -2.0% (95% CI:-3.4,-0.5, p(FDR) = 0.017) lower. These associations were independent of the offspring's own young adulthood BMI, and other important covariates. Conclusion Our findings show that young adult offspring born to mothers with higher early pregnancy BMI show lower average levels of diurnal cortisol, especially in the morning. Whether these findings reflect prenatal programming of the offspring HPA-axis activity warrants further investigation.Peer reviewe
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