573 research outputs found
Adolescent attachment in Nepal: testing the factorial validity of two scales
Attachment theory is an important framework in the psychology of human development and has direct relevance to the study of adolescence. The cross-cultural validity of attachment constructs and measures has been the subject of lively debate among experts. Using confirmatory factor analysis, the present study tested the factor structure of the Adolescent Attachment Questionnaire and the Adolescent Unresolved Attachment Questionnaire in a sample of 279 Nepali adolescents. The hypothesised models had a good fit and further tests established the measurement invariance of the two instruments. The cross-cultural validity of the measures was supported but areas of cultural variation were also highlighted
Applications of cyclotron based ion scattering
Ion scattering experiments have been performed with a 3-30 MeV AVF cyclotron. The wide range of available energies combined with proper beam handling allows many scattering techniques to perform. At first an example of ordinary Rutherford backscattering spectrometry will be demonstrated on model catalysts as studied in surface chemistry. High energy backscattering spectrometIy with 8.8 MeV He ions, which enhances the sensitivity for oxygen, has been applied to study the oxygen removal from corroded archaeological artefacts upon treatment with a H, plasma. Elastic recoil detection analysis will be shown feasible with He ions having incident energies between 10 and 15 MeV once combined with a thin film detector. The development of a setup for ion channeling experiments with the cyclotron is reported and first results promise to increase the angular resolution in lattice deformation studies
Influence of a partially oxidized calcium cathode on the performance of polymeric light emitting diodes
We investigated the influence of the presence of oxygen during the deposition of the calcium cathode on the structure and on the performance of polymeric light emitting diodes (pLEDs). The oxygen background pressure during deposition of the calcium cathode of polymeric LEDs was varied. Subsequently, the oxygen depth distribution was measured and correlated with the
performance of the pLEDs. The devices have been fabricated in a recently built ultraclean setup. The polymer layers of the pLEDs have been spincoated in a dry nitrogen atmosphere and transported directly into an ultrahigh vacuum chamber where the metal electrodes have been deposited by evaporation. We used indiumâtinâoxide as anode, OC1C10 PPV as electroluminescent
polymer, calcium as cathode, and aluminum as protecting layer. We achieved reproducibility of about 15% in current and brightness for devices fabricated in an oxygen atmosphere of less than or equal to 10 -9 mbar. For further investigations the calcium deposition was carried out in an oxygen atmosphere from 10 -8 to 10 -5 mbar. We determined the amount of oxygen in the different layers of the currentâvoltage-light characterized pLEDs with elastic recoil detection analysis and
correlated it with the characteristics of the devices. The external efficiency of the pLEDs decreases continuously with increasing oxygen pressure, the current shows a pronounced minimum. The brightness mostly decreases with increasing oxygen with an indication of a slight minimum. PLEDs
with completely oxidized calcium are not operational. The first contact of the pLEDs with the dry glove box environment leads to an immediate reduction of current and brightness which is caused by the cooling of the devices by several degrees. Determining reproducible characteristics of pLEDs
in the vacuum requires the measurement of their temperature
Baseline Functioning and Stress Reactivity in Maltreating Parents and At-Risk Adults: Review and Meta-Analyses of Autonomic Nervous System Studies.
We reviewed and meta-analyzed 10 studies ( N = 492) that examined the association between (risk for) child maltreatment perpetration and basal autonomic activity, and 10 studies ( N = 471) that examined the association between (risk for) child maltreatment and autonomic stress reactivity. We hypothesized that maltreating parents/at-risk adults would show higher basal levels of heart rate (HR) and skin conductance (SC) and lower levels of HR variability (HRV) and would show greater HR and SC stress reactivity, but blunted HRV reactivity. A narrative review showed that evidence from significance testing within and across studies was mixed. The first set of meta-analyses revealed that (risk for) child maltreatment was associated with higher HR baseline activity ( g = 0.24), a possible indication of allostatic load. The second set of meta-analyses yielded no differences in autonomic stress reactivity between maltreating/at-risk participants and nonmaltreating/low-risk comparison groups. Cumulative meta-analyses showed that positive effects for sympathetic stress reactivity as a risk factor for child maltreatment were found in a few early studies, whereas each subsequently aggregated study reduced the combined effect size to a null effect, an indication of the winner's curse. Most studies were underpowered. Future directions for research are suggested.The study was supported by the Netherlands Organization for Scientific Research (LRAA: VIDI grant; MHvIJ: NWO SPINOZA prize; MJBK: VICI grant), and the Wellcome Trust (WT103343MA).This is the final version of the article. It first appeared from SAGE Publications via http://dx.doi.org/10.1177/1077559516659937
Par1b induces asymmetric inheritance of plasma membrane domains via LGN-dependent mitotic spindle orientation in proliferating hepatocytes
The development and maintenance of polarized epithelial tissue requires a tightly controlled orientation of mitotic cell division relative to the apical polarity axis. Hepatocytes display a unique polarized architecture. We demonstrate that mitotic hepatocytes asymmetrically segregate their apical plasma membrane domain to the nascent daughter cells. The non-polarized nascent daughter cell can form a de novo apical domain with its new neighbor. This asymmetric segregation of apical domains is facilitated by a geometrically distinct âapicolateralâ subdomain of the lateral surface present in hepatocytes. The polarity protein partitioning-defective 1/microtubule-affinity regulating kinase 2 (Par1b/MARK2) translates this positional landmark to cortical polarity by promoting the apicolateral accumulation of Leu-Gly-Asn repeat-enriched protein (LGN) and the capture of nuclear mitotic apparatus protein (NuMA)âpositive astral microtubules to orientate the mitotic spindle. Proliferating hepatocytes thus display an asymmetric inheritance of their apical domains via a mechanism that involves Par1b and LGN, which we postulate serves the unique tissue architecture of the developing liver parenchyma
Mifepristone treatment during early adolescence fails to restore maternal deprivation-induced deficits in behavioral inhibition of adult male rats
Development Psychopathology in context: famil
White Matter Microstructure and the General Psychopathology Factor in Children
Objective: Co-occurrence of behavioral and emotional problems in childhood is widespread, and previous studies have suggested that this reflects vulnerability to experience a range of psychiatric problems, often termed a general psychopathology factor. However, the neurobiological substrate of this general factor is not well understood. We tested the hypothesis that lower overall white matter microstructure is associated with higher levels of the general psychopathology factor in children and less with specific factors. Method: Global white matter microstructure at age 10 years was related to general and specific psychopathology factors. These factors were estimated using a latent bifactor model with multiple informants and instruments between ages 6 and 10 years in 3,030 children from the population-based birth cohort Generation R. The association of global white matter microstructure and the psychopathology factors was examined with a structural equation model adjusted for sex, age at scan, age at psychopathology assessment, parental education/income, and genetic ancestry. Results: A 1-SD increase of the global white matter factor was associated with a β = â0.07SD (standard error [SE] = 0.02, p < .01) decrease in general psychopathology. In contrast, a 1-SD increase of white matter microstructure predicted an increase of β = +0.07 SD (SE = 0.03, p < .01) specific externalizing factor levels. No association was found with the specific internalizing and specific attention factor. Conclusion: The results suggest that general psychopathology in childhood is related to white matter structure across the brain and not only to specific tracts. Taking into account general psychopathology may also help reveal neurobiological mechanisms behind specific symptoms that are otherwise obscured by comorbidity
Interface formation in K doped poly(dialkoxy-p-phenylene vinylene) light-emitting diodes
Manufacturing of Al/K/OC1C10 poly(p-phenylene vinylene)/indiumâtinâoxide light emitting diode structures by physical vapor deposition of K onto the emissive polymer layer has been characterized by electroluminescence and ion spectroscopy. Varying the deposited K areal density from 3.9Ă1012 to 1.2Ă1014âatomsâcmâ2 the external efficiency rises from 0.01 to 1.2 Cd Aâ1. Spectra obtained by ion scattering analysis demonstrate the overall absence of K at the polymer outermost surface layer, and diffusion up to a depth of 200 Ă
. Depth profiles have been derived, and were modeled using an irreversible first order âtrappingâ reaction. Trapping may stem from confinement of the electron at a conjugated segment, that was donated through charge transfer typical for alkali/Ď-conjugated systems. This study demonstrates that evaporation of low work function metals onto organic systems should not be depicted as simple layered stacking structures. The enhanced electroluminescence with submonolayer K deposition is attributed to the shift of the recombination zone away from the Al cathode, which is demonstrated to prevail over the known exciton quenching mechanism due to the formation of gap states
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