710 research outputs found

    Teachers’ Perceptions of a Multiple High-Risk Behavior Prevention Program and Delivery of Universal Programming

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    Much of the success of high-risk behavior prevention programs rests with teachers who deliver the curriculum however; few studies have investigated teachers\u27 perceptions of program implementation. The objective of this phenomenological study was to answer the question, “What are the experiences of teachers who are asked to be involved in the implementation process when their school adopts a multiple high-risk behavior prevention program”? Participants included 10 teachers at a local, private high school in the Southern United States. Five themes emerged: (a) lack of consistent historical effort, (b) need for program, (c) positive but tentative perceptions, (d) challenges with implementation, and (e) review of program counselor. The qualitative results identified factors that can promote or hinder success of the program

    Leaders and Recruiters from the Next Generation: A Phenomenological Study

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    Studies involving student ambassadors have demonstrated their significance in recruiting prospective students to universities and colleges but they have not included the perceptions of the student ambassadors themselves. The purpose of this phenomenological study was to describe the perceptions and experiences of students who served as student ambassadors for their educational institution. Fifteen student ambassadors provided individual descriptions of their perceptions of being an ambassador. Four themes provided a description of ambassadors’ perceptions: (a) belonging, (b) personal growth, (c) diversity, and (d) recruitment. A discussion of the benefits of student ambassadors as leaders are presented in terms of their ability to recruit for the university and college as well as the impact being a leader has on the ambassadors themselves

    International Students’ Transition Experiences in Rural Texas: A Phenomenological Study

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    Due to the growth in the number of international students attending universities in Texas and the need to provide appropriate counseling services to them, nine international students were interviewed about their experiences of transitioning from their home country to college in rural Texas. The authors employed the transcendental phenomenological approach to qualitative research (Moustakas, 1994) which allowed for the following seven emergent themes were identified that described the participants’ experiences: American TV; Knowing Someone; Like a Movie; Everybody Saying Hi; Transportation is Inconvenient; I Miss Noodles; and Being Optimistic. The emergent themes provided the basis for implications and recommendations for counseling services with the international student populations. Implications and recommendations for counselors on college campuses include, but are not limited to: actively collaborating with international student services, participating in new international student orientation services, and developing preemptive approaches to assisting international student during their transitions The authors make recommendations for further qualitative research and focus groups inquiries should be conducted by college counselors to better inform outreach services, for campus counseling and career service center, directed at assisting international students during their numerous transitions (LĂ©rtora et al., 2017)

    Invited Review: IPCC, Agriculture and Food - A Case of Shifting Cultivation and History.

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    Since 1990 the Intergovernmental Panel on Climate Change (IPCC) has produced five Assessment Reports (ARs), in which agriculture as the production of food for humans via crops and livestock have featured in one form or another. A constructed data base of the ca. 2,100 cited experiments and simulations in the five ARs were analysed with respect to impacts on yields via crop type, region and whether or not adaptation was included. Quantitative data on impacts and adaptation in livestock farming have been extremely scarce in the ARs. The main conclusions from impact and adaptation are that crop yields will decline but that responses have large statistical variation. Mitigation assessments in the ARs have used both bottom-up and top-down methods but need better to link emissions and their mitigation with food production and security. Relevant policy options have become broader in later ARs and included more of the social and non-production aspects of food security. Our overall conclusion is that agriculture and food security, which are two of the most central, critical and imminent issues in climate change, have been dealt with in an unfocussed and inconsistent manner between the IPCC five ARs. This is partly a result of agriculture spanning two IPCC working groups but also the very strong focus on projections from computer crop simulation modelling. For the future, we suggest a need to examine interactions between themes such as crop resource use efficiencies and to include all production and non-production aspects of food security in future roles for integrated assessment models

    Electrostatically confined Quantum Rings in bilayer Graphene

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    We propose a new system where electron and hole states are electrostatically confined into a quantum ring in bilayer graphene. These structures can be created by tuning the gap of the graphene bilayer using nanostructured gates or by position-dependent doping. The energy levels have a magnetic field (B0B_{0}) dependence that is strikingly distinct from that of usual semiconductor quantum rings. In particular, the eigenvalues are not invariant under a B0→−B0B_0 \to -B_0 transformation and, for a fixed total angular momentum index mm, their field dependence is not parabolic, but displays two minima separated by a saddle point. The spectra also display several anti-crossings, which arise due to the overlap of gate-confined and magnetically-confined states.Comment: 5 pages, 6 figures, to appear in Nano Letter

    A direct kinematical derivation of the relativistic Sagnac effect for light or matter beams

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    The Sagnac time delay and the corresponding Sagnac phase shift, for relativistic matter and electromagnetic beams counter-propagating in a rotating interferometer, are deduced on the ground of relativistic kinematics. This purely kinematical approach allows to explain the ''universality'' of the effect, namely the fact that the Sagnac time difference does not depend on the physical nature of the interfering beams. The only prime requirement is that the counter-propagating beams have the same velocity with respect to any Einstein synchronized local co-moving inertial frame.Comment: 10 pages, 1 EPS figure, to appear in General Relativity and Gravitatio

    Side Chain Hydrophobicity Modulates Therapeutic Activity and Membrane Selectivity of Antimicrobial Peptide Mastoparan-X

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    The discovery of new anti-infective compounds is stagnating and multi-resistant bacteria continue to emerge, threatening to end the "antibiotic era". Antimicrobial peptides (AMPs) and lipo-peptides such as daptomycin offer themselves as a new potential class of antibiotics; however, further optimization is needed if AMPs are to find broad use as antibiotics. In the present work, eight analogues of mastoparan-X (MPX) were investigated, having side chain modifications in position 1, 8 and 14 to modulate peptide hydrophobicity. The self-association properties of the peptides were characterized, and the peptide-membrane interactions in model membranes were compared with the bactericidal and haemolytic properties. Alanine substitution at position 1 and 14 resulted in higher target selectivity (red blood cells versus bacteria), but also decreased bactericidal potency. For these analogues, the gain in target selectivity correlated to biophysical parameters showing an increased effective charge and reduction in the partitioning coefficient for membrane insertion. Introduction of an unnatural amino acid, with an octyl side chain by amino acid substitution, at positions 1, 8 and 14 resulted in increased bactericidal potency at the expense of radically reduced membrane target selectivity. Overall, optimized membrane selectivity or bactericidal potency was achieved by changes in side chain hydrophobicity of MPX. However, enhanced potency was achieved at the expense of selectivity and vice versa in all cases

    Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation.

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    Objectives: Ultra-small superparamagnetic particles of iron oxide (USPIO)-enhanced MRI can detect cellular inflammation within tissues and may help non-invasively identify cardiac transplant rejection. Here, we aimed to determine the normal reference values for USPIO-enhanced MRI in patients with a prior cardiac transplant and examine whether USPIO-enhanced MRI could detect myocardial inflammation in patients with transplant rejection. Methods: Ten volunteers and 11 patients with cardiac transplant underwent T2, T2* and late gadolinium enhancement 1.5T MRI, with further T2* imaging at 24 hours after USPIO (ferumoxytol, 4 mg/kg) infusion, at baseline and 3 months. Results: Ten patients with clinically stable cardiac transplantation were retained for analysis. Myocardial T2 values were higher in patients with cardiac transplant versus healthy volunteers (53.8±5.2 vs 48.6±1.9 ms, respectively; p=0.003). There were no differences in the magnitude of USPIO-induced change in R2* in patients with transplantation (change in R2*, 26.6±7.3 vs 22.0±10.4 s-1 in healthy volunteers; p=0.28). After 3 months, patients with transplantation (n=5) had unaltered T2 values (52.7±2.8 vs 52.12±3.4 ms; p=0.80) and changes in R2* following USPIO (29.42±8.14 vs 25.8±7.8 s-1; p=0.43). Conclusion: Stable patients with cardiac transplantation have increased myocardial T2 values, consistent with resting myocardial oedema or fibrosis. In contrast, USPIO-enhanced MRI is normal and stable over time suggesting the absence of chronic macrophage-driven cellular inflammation. It remains to be determined whether USPIO-enhanced MRI may be able to identify acute cardiac transplant rejection. Trial registration number: NCT02319278349 (https://clinicaltrials.gov/ct2/show/NCT02319278) Registered 03.12.2014 EUDraCT 2013-002336-24

    FAK acts as a suppressor of RTK-MAP kinase signalling in Drosophila melanogaster epithelia and human cancer cells

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    Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also observed in MDA-MB-231 human breast cancer cells, suggesting it is a conserved phenomenon in humans. Mechanistically, FAK reduced receptor recycling into the plasma membrane, which resulted in lower MAPK activation. Conversely, increasing the membrane pool of the receptor increased MAPK pathway signalling. FAK is widely considered as a therapeutic target in cancer biology; however, it also has tumour suppressor properties in some contexts. Therefore, the FAK-mediated negative regulation of RTK/MAPK signalling described here may have potential implications in the designing of therapy strategies for RTK-driven tumours
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