Cu-Doping Effects in CdI2Nanocrystals: The Role of Cu-Agglomerates

Cu-doping effects in CdI2nanocrystals are studied experimentally. We use the photostimulated second harmonic generation (PSSHG) as a tool to investigate the effects. It is found that the PSSHG increases with increasing Cu content up to 0.6% and then decreases due to the formation of the Cu-agglomerates. The PSSHG for the crystal with Cu content higher than 1% reduces to that for the undoped CdI2crystal. The results suggest that a crucial role of the Cu-metallic agglomerates is involved in the processes as responsible for the observed effects

Assessing newborn body composition using principal components analysis: differences in the determinants of fat and skeletal size

BACKGROUND: Birth weight is a composite of skeletal size and soft tissue. These components are likely to have different growth patterns. The aim of this paper is to investigate the association between established determinants of birth weight and these separate components. METHODS: Weight, length, crown-rump, knee-heel, head circumference, arm circumference, and skinfold thicknesses were measured at birth in 699 healthy, term, UK babies recruited as part of the Exeter Family Study of Childhood Health. Corresponding measurements were taken on both parents. Principal components analysis with varimax rotation was used to reduce these measurements to two independent components each for mother, father and baby: one highly correlated with measures of fat, the other with skeletal size. RESULTS: Gestational age was significantly related to skeletal size, in both boys and girls (r = 0.41 and 0.52), but not fat. Skeletal size at birth was also associated with parental skeletal size (maternal: r = 0.24 (boys), r = 0.39 (girls) ; paternal: r = 0.16 (boys), r = 0.25 (girls)), and maternal smoking (0.4 SD reduction in boys, 0.6 SD reduction in girls). Fat was associated with parity (first borns smaller by 0.45 SD in boys; 0.31 SD in girls), maternal glucose (r = 0.18 (boys); r = 0.27 (girls)) and maternal fat (r = 0.16 (boys); r = 0.36 (girls)). CONCLUSION: Principal components analysis with varimax rotation provides a useful method for reducing birth weight to two more meaningful components: skeletal size and fat. These components have different associations with known determinants of birth weight, suggesting fat and skeletal size may have different regulatory mechanisms, which would be important to consider when studying the associations of birth weight with later adult disease

Carrier concentration dependence of optical Kerr nonlinearity in indium tin oxide films

Optical Kerr nonlinearity (n2) in n-type indium tin oxide (ITO) films coated on glass substrates has been measured using Z-scans with 200-fs laser pulses at wavelengths ranging from 720 to 780 nm. The magnitudes of the measured nonlinearity in the ITO films were found to be dependent on the carrier concentration with a maximum n2-value of 4.1 x 10-5 cm2/GW at 720-nm wavelength and an electron density of Nd = 5.8 x 1020 cm-3. The Kerr nonlinearity was also observed to be varied with the laser wavelength. By employing a femtosecond time-resolved optical Kerr effect (OKE) technique, the relaxation time of OKE in the ITO films is determined to be ~1 ps. These findings suggest that the Kerr nonlinearity in ITO can be tailored by controlling the carrier concentration, which should be highly desirable in optoelectronic devices for ultrafast all-optical switching.Comment: 15 pages, 1 table, 4 figure

Postcopulatory sexual selection

The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to generate a startling diversity of morphological, behavioural and physiological adaptations. We identify three main issues that should be resolved to advance our understanding of postcopulatory sexual selection. We need to determine the genetic basis of different male fertility traits and female traits that mediate sperm selection; identify the genes or genomic regions that control these traits; and establish the coevolutionary trajectory of sexes

Factors associated with internalizing or somatic symptoms in a cross-sectional study of school children in grades 1-10

<p>Abstract</p> <p>Background</p> <p>School related factors that may contribute to children's subjective health have not been extensively studied. We assessed whether factors assumed to promote health and factors assumed to have adverse effects were associated with self-reported internalizing or somatic symptoms.</p> <p>Methods</p> <p>In a cross-sectional study, 230 boys and 189 girls in grades 1-10 from five schools responded to the same set of questions. Proportional odds logistic regression was used to assess associations of school related factors with the prevalence of sadness, anxiety, stomach ache, and headache.</p> <p>Results</p> <p>In multivariable analyses, perceived loneliness showed strong and positive associations with sadness (odds ratio, 1.94, 95% CI 1.42 to 2.64), anxiety (odds ratio, 1.78, 95% CI 1.31 to 2.42), and headache (odds ratio, 1.47, 95% CI 1.10 to 1.96), with consistently stronger associations for girls than boys. Among assumed health promoting factors, receiving necessary help from teachers was associated with lower prevalence of stomach ache in girls (odds ratio, 0.51, 95% CI 0.30 to 0.87).</p> <p>Conclusions</p> <p>These findings suggest that perceived loneliness may be strongly related to both internalizing and somatic symptoms among school children, and for girls, the associations of loneliness appear to be particularly strong.</p

The influence of salinity on the effects of Multi-walled carbon nanotubes on polychaetes

Salinity shifts in estuarine and coastal areas are becoming a topic of concern and are one of the main factors influencing nanoparticles behaviour in the environment. For this reason, the impacts of multiwalled carbon nanotubes (MWCNTs) under different seawater salinity conditions were evaluated on the common ragworm Hediste diversicolor, a polychaete species widely used as bioindicator of estuarine environmental quality. An innovative method to assess the presence of MWCNT aggregates in the sediments was used for the first time. Biomarkers approach was used to evaluate the metabolic capacity, oxidative status and neurotoxicity of polychaetes after long-term exposure. The results revealed an alteration of energy-related responses in contaminated polychaetes under both salinity conditions, resulting in an increase of metabolism and expenditure of their energy reserves (lower glycogen and protein contents). Moreover, a concentration-dependent toxicity (higher lipid peroxidation, lower ratio between reduced and oxidized glutathione and activation of antioxidant defences and biotransformation mechanisms) was observed in H. diversicolor, especially when exposed to low salinity. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs at both salinities.publishe

A school-based resilience intervention to decrease tobacco, alcohol and marijuana use in high school students

<p>Abstract</p> <p>Background</p> <p>Despite schools theoretically being an ideal setting for accessing adolescents and preventing initiation of substance use, there is limited evidence of effective interventions in this setting. Resilience theory provides one approach to achieving such an outcome through improving adolescent mental well-being and resilience. A study was undertaken to examine the potential effectiveness of such an intervention approach in improving adolescent resilience and protective factor scores; and reducing the prevalence of adolescent tobacco, alcohol and marijuana use in three high schools.</p> <p>Methods</p> <p>A non-controlled before and after study was undertaken. Data regarding student resilience and protective factors, and measures of tobacco, alcohol and marijuana use were collected from grade 7 to 10 students at baseline (n = 1449) and one year following a three year intervention (n = 1205).</p> <p>Results</p> <p>Significantly higher resilience and protective factors scores, and significantly lower prevalence of substance use were evident at follow up.</p> <p>Conclusions</p> <p>The results suggest that the intervention has the potential to increase resilience and protective factors, and to decrease the use of tobacco, alcohol and marijuana by adolescents. Further more rigorous research is required to confirm this potential.</p

The personal and contextual contributors to school belongingness among primary school students

School belongingness has gained currency among educators and school health professionals as an important determinant of adolescent health. The current cross-sectional study presents the 15 most significant personal and contextual factors that collectively explain 66.4% (two-thirds) of the variability in 12-year old students' perceptions of belongingness in primary school. The study is part of a larger longitudinal study investigating the factors associated with student adjustment in the transition from primary to secondary school. The study found that girls and students with disabilities had higher school belongingness scores than boys, and their typically developing counterparts respectively; and explained 2.5% of the variability in school belongingness. The majority (47.1% out of 66.4%) of the variability in school belongingness was explained by student personal factors, such as social acceptance, physical appearance competence, coping skills, and social affiliation motivation; followed by parental expectations (3% out of 66.4%), and school-based factors (13.9% out of 66.4%) such as, classroom involvement, task-goal structure, autonomy provision, cultural pluralism, and absence of bullying. Each of the identified contributors of primary school belongingness can be shaped through interventions, system changes, or policy reforms