90 research outputs found

    School-based data and management of technological innovations in public secondary schools in Cross River State

    Get PDF
    This study investigated the relationship between school-based data and management of technological innovations in public secondary schools in Cross River State. One hypothesis was formulated to guide the study. Ex-post facto design was used for the study. The population of this study consisted of 232 principals out of which 210 constituted the sample and 840 teachers were drawn from a population of 5,998 using stratified random sampling technique to assess the principals. School- based Data and management of Technological Innovation Questionnaire (SBDMTIQ) was instrument used for data collection. Pearsonā€™s Product Moment Correlation Analysis was used to test the hypothesis. Result indicated that: there is no significant positive relationship between school-based data and principals management of technological innovation. It was recommended that government should give priority attention to the provision and distribution of ICT facilities in schools so as to boost the management of innovations in schools.Keywords: Data, management, technological, innovatio

    Wannier-Bloch Approach to Localization in High-Harmonics Generation in Solids

    No full text
    Emission of high-order harmonics from solids provides a new avenue in attosecond science. On the one hand, it allows us to investigate fundamental processes of the nonlinear response of electrons driven by a strong laser pulse in a periodic crystal lattice. On the other hand, it opens new paths toward efficient attosecond pulse generation, novel imaging of electronic wave functions, and enhancement of high-order harmonic-generation (HHG) intensity. A key feature of HHG in a solid (as compared to the well-understood phenomenon of HHG in an atomic gas) is the delocalization of the process, whereby an electron ionized from one site in the periodic lattice may recombine in any other. Here, we develop an analytic model, based on the localized Wannier wave functions in the valence band and delocalized Bloch functions in the conduction band. This Wannier-Bloch approach assesses the contributions of individual lattice sites to the HHG process and hence precisely addresses the question of localization of harmonic emission in solids. We apply this model to investigate HHG in a ZnO crystal for two different orientations, corresponding to wider and narrower valence and conduction bands, respectively. Interestingly, for narrower bands, the HHG process shows significant localization, similar to harmonic generation in atoms. For all cases, the delocalized contributions to HHG emission are highest near the band-gap energy. Our results pave the way to controlling localized contributions to HHG in a solid crystal

    Impact of measurement backaction on nuclear spin qubits in silicon

    Full text link
    Phosphorus donor nuclear spins in silicon couple weakly to the environment making them promising candidates for high-fidelity qubits. The state of a donor nuclear spin qubit can be manipulated and read out using its hyperfine interaction with the electron confined by the donor potential. Here we use a master equation-based approach to investigate how the backaction from this electron-mediated measurement affects the lifetimes of single and multi-donor qubits. We analyze this process as a function of electric and magnetic fields, and hyperfine interaction strength. Apart from single nuclear spin flips, we identify an additional measurement-related mechanism, the nuclear spin flip-flop, which is specific to multi-donor qubits. Although this flip-flop mechanism reduces qubit lifetimes, we show that it can be effectively suppressed by the hyperfine Stark shift. We show that using atomic precision donor placement and engineered Stark shift, we can minimize the measurement backaction in multi-donor qubits, achieving larger nuclear spin lifetimes than single donor qubits

    Obesity and motor skills among 4 to 6-year-old children in the united states: nationally-representative surveys

    Get PDF
    Few population-based studies have assessed relationships between body weight and motor skills in young children. Our objective was to estimate the association between obesity and motor skills at 4 years and 5-6 years of age in the United States. We used repeated cross-sectional assessments of the national sample from the Early Childhood Longitudinal Survey-Birth Cohort (ECLS-B) of preschool 4-year-old children (2005-2006; n = 5 100) and 5-6-year-old kindergarteners (2006-2007; n = 4 700). Height, weight, and fine and gross motor skills were assessed objectively via direct standardized procedures. We used categorical and continuous measures of body weight status, including obesity (Body Mass Index (BMI) ā‰„ 95th percentile) and BMI z-scores. Multivariate logistic and linear models estimated the association between obesity and gross and fine motor skills in very young children adjusting for individual, social, and economic characteristics and parental involvement.info:eu-repo/semantics/publishe
    • ā€¦
    corecore