443 research outputs found
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Specification of optical components using the power spectral density function
This paper describes the use of Fourier techniques to characterize the wavefront of optical components, specifically, the use of the power spectral density, (PSD), function. The PSDs of several precision optical components will be shown. Many of the optical components of interest to us have square, rectangular or irregularly shaped apertures with major dimensions up-to 800 mm. The wavefronts of components with non-circular apertures cannot be analyzed with Zernicke polynomials since these functions are an orthogonal set for circular apertures only. Furthermore, Zernicke analysis is limited to treating low frequency wavefront aberrations; mid-spatial scale and high frequency error are expressed only as ``residuals.`` A more complete and powerful representation of the optical wavefront can be obtained by Fourier analysis in 1 or 2 dimensions. The PSD is obtained from the amplitude of frequency components present in the Fourier spectrum. The PSD corresponds to the scattered intensity as a function of scattering angle in the wavefront and can be used to describe the intensity distribution at focus. The shape of a resultant wavefront or the focal spot of a complex multi-component laser system can be calculated and optimized using the PSDs of individual optical components which comprise it
An Analytic Study of the Professional Development Research in Early Childhood Education
The goal of this study was to examine empirical research on the design, delivery, and measurement of the effects of professional development (PD) for early childhood educators in order to provide insight into what the field has accomplished as well as suggest directions for future PD programs and research. Through the use of rigorous inclusion criteria outlined by S. M. Wilson, R. E. Floden, and J. Ferrini-Mundy (2001), 73 studies were included and analyzed. On average, 25% (M = 12.68, SD = 9.99) of references in each study were specifically about PD. The majority of studies (n = 39) targeted some form of language and literacy instruction, whereas only 5 studies targeted math and 1 study targeted science. A total of 35 different delivery mechanisms were used to provide PD, with 40 studies including some form of coaching and 45 including training workshops. The studies used a wide range of methods to measure PD-related outcomes: 51% (n = 37) of studies examined changes in teacher practice, 18% (n = 13) measured changes in teachersâ knowledge, 40% (n = 29) measured changes in childrenâs learning, and 11% (n = 8) measured changes in childrenâs behavior. Practice or Policy: Based on the results of this study, there are 4 major ways in which PD for early childhood educators can be developed. Researchers and providers of PD should (a) continue to draw from multiple resources to inform PD implementation designs, (b) include more diversity in the content of instruction targeted by PD, (c) experiment with innovative formats for delivering PD, and (d) create better means of evaluating PD
Protocol for the saMS trial (supportive adjustment for multiple sclerosis): a randomized controlled trial comparing cognitive behavioral therapy to supportive listening for adjustment to multiple sclerosis
BackgroundMultiple Sclerosis (MS) is an incurable, chronic, potentially progressive and unpredictable disease of the central nervous system. The disease produces a range of unpleasant and debilitating symptoms, which can have a profound impact including disrupting activities of daily living, employment, income, relationships, social and leisure activities, and life goals. Adjusting to the illness is therefore particularly challenging. This trial tests the effectiveness of a cognitive behavioural intervention compared to supportive listening to assist adjustment in the early stages of MS.MethodsThis is a two arm randomized multi-centre parallel group controlled trial. 122 consenting participants who meet eligibility criteria will be randomly allocated to receive either Cognitive Behavioral Therapy or Supportive Listening. Eight one hour sessions of therapy (delivered over a period of 10 weeks) will be delivered by general nurses trained in both treatments. Self-report questionnaire data will be collected at baseline (0 weeks), mid-therapy (week 5 of therapy), post-therapy (15 weeks) and at six months (26 weeks) and twelve months (52 weeks) follow-up. Primary outcomes are distress and MS-related social and role impairment at twelve month follow-up. Analysis will also consider predictors and mechanisms of change during therapy. In-depth interviews to examine participantsâ experiences of the interventions will be conducted with a purposively sampled sub-set of the trial participants. An economic analysis will also take place. DiscussionThis trial is distinctive in its aims in that it aids adjustment to MS in a broad sense. It is not a treatment specifically for depression. Use of nurses as therapists makes the interventions potentially viable in terms of being rolled out in the NHS. The trial benefits from incorporating patient input in the development and evaluation stages. The trial will provide important information about the efficacy, cost-effectiveness and acceptability of the interventions as well as mechanisms of psychosocial adjustment.Trial registrationCurrent Controlled Trials ISRCTN91377356<br/
Validation of the questionnaire on beliefs about medication with type 2 diabetic patients
O presente trabalho teve como objectivo validar o QuestionĂĄrio Crenças sobre a Medicação, que avalia Crenças Gerais e Crenças EspecĂficas, estudando suas propriedades psicomĂ©tricas em uma amostra de 387 pacientes diabĂ©ticos tipo 2. O estudo de validade para as Crenças Gerais revelou uma solução de um factor, com um alfa de 0,76, e para as Crenças EspecĂficas, dois factores â Necessidades e PreocupaçÔes â, com um alfa de 0,77 e 0,69 respectivamente. Quanto Ă validade de constructo, verificou-se uma relação entre as Crenças Gerais e a subescala Necessidades das Crenças EspecĂficas com AdesĂŁo Ă Medicação, avaliada pela Escala de Avaliação de AderĂȘncia MĂ©dica. O instrumento apresenta boas qualidades psicomĂ©tricas para ser utilizado em pacientes diabĂ©ticos tipo 2.The present paper focused on the validation of the Questionnaire on Beliefs about Medication, which assesses both General Beliefs and Specific Beliefs. The psychometric properties of the instrument were analyzed on a sample of 387 type 2 diabetic patients. The validity study for General Beliefs found a unifactorial solution, with an alpha of .76, and for Specific Beliefs, a two-factor solution â Necessities and Concern â, with an alpha of .77 and .69, respectively. In terms of construct validity, a relationship between General Beliefs, subscale Necessities from Specific Beliefs, and adherence to medication, as evaluated by Medical Adherence Rating Scale, was found. The instrument presents good psychometric qualities to be used in type 2 diabetic patients.Fundação para a CiĂȘncia e Tecnologia (FCT
Electronic Structure and Bonding of Icosahedral Core-Shell Gold-Silver Nanoalloy Clusters Au_(144-x)Ag_x(SR)_60
Atomically precise thiolate-stabilized gold nanoclusters are currently of
interest for many cross-disciplinary applications in chemistry, physics and
molecular biology. Very recently, synthesis and electronic properties of
"nanoalloy" clusters Au_(144-x)Ag_x(SR)_60 were reported. Here, density
functional theory is used for electronic structure and bonding in
Au_(144-x)Ag_x(SR)_60 based on a structural model of the icosahedral
Au_144(SR)_60 that features a 114-atom metal core with 60 symmetry-equivalent
surface sites, and a protecting layer of 30 RSAuSR units. In the optimal
configuration the 60 surface sites of the core are occupied by silver in
Au_84Ag_60(SR)_60. Silver enhances the electron shell structure around the
Fermi level in the metal core, which predicts a structured absorption spectrum
around the onset (about 0.8 eV) of electronic metal-to-metal transitions. The
calculations also imply element-dependent absorption edges for Au(5d)
\rightarrow Au(6sp) and Ag(4d) \rightarrow Ag(5sp) interband transitions in the
"plasmonic" region, with their relative intensities controlled by the Ag/Au
mixing ratio.Comment: 4 figure
A pilot randomized controlled trial for a videoconference-delivered mindfulness-based group intervention in a nonclinical setting
Technology is increasingly being integrated into the provision of therapy and mental health interventions. While the evidence base for technology-led delivery of mindfulness-based interventions is growing, one approach to understanding the effects of technology-delivered elements includes so-named blended programs that continue to include aspects of traditional face-to-face interaction. This arrangement offers unique practical advantages, and also enables researchers to isolate variables that may be underlying the effects of technology-delivered interventions. The present study reports on a pilot videoconference-delivered mindfulness-based group intervention offered to university students and staff members with wait-list controls. Apart from the first session of the six-week course, the main facilitator guided evening classes remotely via online videoconferencing, with follow-up exercises via email. Participants Powered by Editorial ManagerÂź and ProduXion ManagerÂź from Aries Systems Corporation were taught a variety of mindfulness-based exercises such as meditation, breathing exercises, mindful tasting, as well as the concepts underpinning such practice. Participants completed pre- and post-intervention questionnaires on depression, anxiety, repetitive negative thinking, dysfunctional attitudes, positive and negative affect, self-compassion, compassion for others, and mindfulness. For participants who attended at least five of the six sessions, scores on all outcome measures improved significantly post intervention and remained stable at three-week follow up. The videoconference-delivered mindfulness-based group intervention appears to provide a viable alternative format to standard mindfulness programs where the facilitator and participants need to live in close physical proximity with each other
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Intergenerational transmission of literacy skills among Filipino families
We examined the joint role of parental word reading skills and conventional home literacy environment measures among 320 Filipino low- to- middle-income families in Cebu City, Philippines with children aged 5 to 8 years old. A ranking of parent-reported ratings of their frequency of engaging in home literacy activities and adult literacy practices revealed that book-related behaviors were less frequently practiced in this sample, and mean ratings on the home literacy resources scale suggested a relatively print-poor environment. Nevertheless, scale items about book reading and direct literacy instruction at home correlated with childâs literacy skills. Structural equation modeling showed that parentâs education and frequency of engaging in home literacy activities uniquely accounted for variance in childâs oral and print skills. In a second model, parentâs word reading skills were significantly related to childâs skills, but did not eliminate or attenuate influences from parentâs education and home literacy activities. Results are important in relation to theories on the intergenerational transmission of literacy skills and the generalizability of findings from developed countries to developing country contexts
Evaluation of patientsâ experiences with antidepressants reported by means of a medicine reporting system
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A Moment of Mindfulness: Computer-Mediated Mindfulness Practice Increases State Mindfulness
Three studies investigated the use of a 5-minute, computer-mediated mindfulness practice in increasing levels of state mindfulness. In Study 1, 54 high school students completed the computer-mediated mindfulness practice in a lab setting and Toronto Mindfulness Scale (TMS) scores were measured before and after the practice. In Study 2 (N = 90) and Study 3 (N = 61), the mindfulness practice was tested with an entirely online sample to test the delivery of the 5-minute mindfulness practice via the internet. In Study 2 and 3, we found a significant increase in TMS scores in the mindful condition, but not in the control condition. These findings highlight the impact of a brief, mindfulness practice for single-session, computer-mediated use to increase mindfulness as a state
Using quantile regression to investigate racial disparities in medication non-adherence
<p>Abstract</p> <p>Background</p> <p>Many studies have investigated racial/ethnic disparities in medication non-adherence in patients with type 2 diabetes using common measures such as medication possession ratio (MPR) or gaps between refills. All these measures including MPR are quasi-continuous and bounded and their distribution is usually skewed. Analysis of such measures using traditional regression methods that model mean changes in the dependent variable may fail to provide a full picture about differential patterns in non-adherence between groups.</p> <p>Methods</p> <p>A retrospective cohort of 11,272 veterans with type 2 diabetes was assembled from Veterans Administration datasets from April 1996 to May 2006. The main outcome measure was MPR with quantile cutoffs Q1-Q4 taking values of 0.4, 0.6, 0.8 and 0.9. Quantile-regression (QReg) was used to model the association between MPR and race/ethnicity after adjusting for covariates. Comparison was made with commonly used ordinary-least-squares (OLS) and generalized linear mixed models (GLMM).</p> <p>Results</p> <p>Quantile-regression showed that Non-Hispanic-Black (NHB) had statistically significantly lower MPR compared to Non-Hispanic-White (NHW) holding all other variables constant across all quantiles with estimates and p-values given as -3.4% (p = 0.11), -5.4% (p = 0.01), -3.1% (p = 0.001), and -2.00% (p = 0.001) for Q1 to Q4, respectively. Other racial/ethnic groups had lower adherence than NHW only in the lowest quantile (Q1) of about -6.3% (p = 0.003). In contrast, OLS and GLMM only showed differences in mean MPR between NHB and NHW while the mean MPR difference between other racial groups and NHW was not significant.</p> <p>Conclusion</p> <p>Quantile regression is recommended for analysis of data that are heterogeneous such that the tails and the central location of the conditional distributions vary differently with the covariates. QReg provides a comprehensive view of the relationships between independent and dependent variables (i.e. not just centrally but also in the tails of the conditional distribution of the dependent variable). Indeed, without performing QReg at different quantiles, an investigator would have no way of assessing whether a difference in these relationships might exist.</p
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