287 research outputs found

    Effects of Learning Guided Discovery Using Map Concept of Process Skills and Abilities Cognitive Science Physics Students SMA

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    The purpose of this study were to analyze science process skill and physics cognitive competence taught of students by guided discovery learning by using the concept maps or taught by conventional learning. The research type was quasi experiment with the two group pre-test and post test design, and the population of this study was all students class X semester II at senior high school 1 Pancur Batu. The research sample was taken by simple random sampling technique consist of two class, theyare the experimental class taught by the guided discovery learning by using the concept maps and the control class taught by the conventional learning. The data of this research was taken using observation sheet to see the science process skill of students and multiple choice test to see the students\u27 physics cognitive competence. The result showed that the average value of science process skills of students in the experimental class is 69.26, while in the control class 47.72 and cognitive competence taught of students\u27 physics class experiment was 81.33, while in the control class 75.50. The results of this research indicated that science process skill of students on and physics cognitive competence taught by the guided discovery learning by using the concept maps was better than taught by the conventional learning

    GaAs(111)A and B in hydrazine sulfide solutions : extreme polarity dependence of surface adsorption processes

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    Chemical bonds formed by hydrazine-sulfide treatment of GaAs(111) were studied by synchrotron photoemission spectroscopy. At the B surface, the top arsenic atoms are replaced by nitrogen atoms, while GaAs(111)A is covered by sulfur, also bonded to underlying gallium, despite the sulfide molar concentration being 103 times smaller than that of the hydrazine. This extreme dependence on surface polarity is explained by competitive adsorption processes of HS- and OH- anions and of hydrazine molecules, on Ga- adsorption sites, which have distinct configurations on the A and B surfaces

    Absence of an intrinsic value for the surface recombination velocity in doped semiconductors

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    A self-consistent expression for the surface recombination velocity SS and the surface Fermi level unpinning energy as a function of light excitation power (PP) is presented for n- and p-type semiconductors doped above the 1016^{16} cm−3^{-3} range. Measurements of SS on p-type GaAs films using a novel polarized microluminescence technique are used to illustrate two limiting cases of the model. For a naturally oxidized surface SS is described by a power law in PP whereas for a passivated surface S−1S^{-1} varies logarithmically with PP. Furthermore, the variation in SS with surface state density and bulk doping level is found to be the result of Fermi level unpinning rather than a change in the intrinsic surface recombination velocity. It is concluded that SS depends on PP throughout the experimentally accessible range of excitation powers and therefore that no instrinsic value can be determined. Previously reported values of SS on a range of semiconducting materials are thus only valid for a specific excitation power.Comment: 10 pages, 7 figure

    Wet chemical nitridation of GaAs (100) by hydrazine solution for surface passivation

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    A mild wet nitridation procedure using hydrazine-based solutions has been developed for GaAs (100) surface passivation. Both x-ray photoelectron spectroscopy and spectroscopic ellipsometry show that this nitridation procedure results in a very thin, coherent, and homogeneous GaN layer that is very stable in air. Photoluminescence data show a strong enhancement of the intensity as compared to that of an as-cleaned GaAs sample, indicating that this nitrided layer provides both chemical and electronic passivation of GaAs surfaces. The chemical mechanism of nitridation is discusse

    Perceptions of rewards among volunteer caregivers of people living with AIDS working in faith-based organizations in South Africa: a qualitative study

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    <p>Abstract</p> <p>Background</p> <p>Volunteer caregivers are a critical source of support for the majority of people living with HIV and AIDS in southern Africa, which has extremely high HIV/AIDS prevalence rates. While studies have shown that volunteer caregiving is associated with negative health and socio-economic outcomes, little is known about the positive experiences of volunteers in the home-based care context in South Africa. The purpose of this study is to explore the perception of rewards among volunteers working in home-based care settings.</p> <p>Methods</p> <p>This study uses a qualitative design. Qualitative interviews were conducted with a purposively selected sample of 55 volunteer caregivers using an interview schedule containing open-ended questions.</p> <p>Results</p> <p>Volunteer caregivers derived intrinsic rewards related to self-growth and personal (emotional and psychological) development on the job; they also derived satisfaction from community members taking a liking for them and expressing a need for their services. Volunteers felt gratified by the improvements in their health behaviours, which were a direct consequence of the experiences of caring for terminally ill patients with AIDS. Extrinsic rewards came from appreciation and recognition shown by patients and community members. Extrinsic rewards also accrued to volunteers when the services they rendered made their patients happy. Perhaps the greatest sources of extrinsic rewards are skills and competencies acquired from training and experience while caring for their patients, and volunteers' ability to make a difference in the community.</p> <p>Conclusions</p> <p>Insights into volunteer caregiver rewards provide opportunities for policy makers and programme managers to develop a model of home-based care that facilitates the accrual of rewards to volunteers alongside volunteers' traditional duties of patient care. Programme managers could employ these insights in recruiting and assisting volunteers to identify and reflect on rewards in the caregiving situation as a means of reducing the burden of care and sustaining volunteer interest in caregiving.</p

    The impact of protocol assignment for older adolescents with Hodgkin lymphoma

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    Background and Purpose: Hodgkin lymphoma (HL) treatment has evolved to reduce or avoid radiotherapy (RT) dose and volume and minimize the potential for late effects. Some older adolescents are treated on adult protocols. The purpose of this study is to examine the protocol assignment of older adolescents and its impact on radiation dose to relevant thoracic structures. Materials and Methods: Cooperative group data were reviewed and 12 adolescents were randomly selected from a pediatric HL protocol. Treatment plans were generated per one pediatric and two adult protocols. Dose volume histograms for heart, lung, and breast allowed comparison of radiation dose to these sites across these three protocols. Results: A total of 15.2% of adolescents were treated on adult HL protocols and received significantly higher radiation dosage to heart and lung compared to pediatric HL protocols. Adolescents treated on either pediatric or adult protocols received similar RT dose to breast. Conclusion: Older adolescents treated on adult HL protocols received higher RT dose to thoracic structures except breast. Level of nodal involvement may impact overall RT dose to breast. The impact of varying field design and RT dose on survival, local, and late effects needs further study for this vulnerable age group

    Young children and tablets: the views of parents and teachers

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    Touch screen tablets are now widely available and due to the increasing use of these technologies in homes and early years centres, it is important to consider parent and teacher views about their use. This paper reports on an interview study which explored the perspectives of four parents of children aged 20–36 months and their two teachers in one early learning centre in the north of England. Key findings were that parents and teachers had a positive perspective on young children’s use of tablets and viewed them as educationally valuable. They expressed that they did not wish children to be left behind in learning about new technologies and emphasized having a ‘balanced’ approach to tablets. However, there were also concerns voiced over the potential overuse and misuse of tablets at home suggesting more guidance for parents is needed to support young children’s experiences with tablets

    Medical Management and Rehabilitation in the Workplace: Emerging Issues

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45004/1/10926_2004_Article_223619.pd

    A qualitative investigation of breast cancer survivors’ experiences with breastfeeding

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    This is an exploratory, qualitative investigation of breast cancer survivors’ experiences with breastfeeding. Previous studies have focused on the physiology of lactation after surgery and treatment, but have not explored factors influencing breastfeeding decisions and behavior. We used purposeful sampling to identify 11 breast cancer survivors who had a child after their diagnosis and treatment. Participants were recruited from among those in the Women’s Healthy Eating and Living (WHEL) study and a Young Survival Coalition (YSC) affiliate. We conducted semi-structured, open-ended telephone interviews lasting 45–75 min. We used social cognitive theory (SCT) to structure questions regarding influences on breastfeeding behavior. We transcribed interviews and used cross-case, inductive analysis to identify themes. Ten of 11 participants initiated breastfeeding. The following main themes emerged: 1) Cautiously hopeful, 2) Exhausting to rely on one breast, 3) Motivated despite challenges, 4) Support and lack of support, and 5) Encouraging to others. Study participants were highly motivated to breastfeed but faced considerable challenges. Participants described problems that are not unique to women with breast cancer, but experienced these to a much greater degree because they relied mostly or entirely on one lactating breast. This study revealed a need for improved access to information and support and greater sensitivity to the obstacles faced by breast cancer survivors. Results of this qualitative analysis indicate that interventions to support the efforts of breast cancer survivors who are interested in breastfeeding are warranted. Additional research would aid in the development of such interventions
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