3,350 research outputs found

    Exciton lifetime and emission polarization dispersion in strongly in-plane asymmetric nanostructures

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    We present experimental and theoretical investigation of exciton recombination dynamics and the related polarization of emission in highly in-plane asymmetric nanostructures. Considering general asymmetry- and size-driven effects, we illustrate them with a detailed analysis of InAs/AlGaInAs/InP elongated quantum dots. These offer a widely varied confinement characteristics tuned by size and geometry that are tailored during the growth process, which leads to emission in the application-relevant spectral range of 1.25-1.65 {\mu}m. By exploring the interplay of the very shallow hole confining potential and widely varying structural asymmetry, we show that a transition from the strong through intermediate to even weak confinement regime is possible in nanostructures of this kind. This has a significant impact on exciton recombination dynamics and the polarization of emission, which are shown to depend not only on details of the calculated excitonic states but also on excitation conditions in the photoluminescence experiments. We estimate the impact of the latter and propose a way to determine the intrinsic polarization-dependent exciton light-matter coupling based on kinetic characteristics.Comment: 11 pages, 8 figure

    Student Perspectives on how Trauma Experiences Manifest in the Classroom: Engaging Court-Involved Youth in the Development of a Trauma-Informed Teaching Curriculum

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    This study explores how the lived experience of court-involved youth impacts learning and school culture, and solicits youth voice in creating a trauma-informed intervention to improve student educational well-being. Thirty-nine female students, ages 14 to 18, participated in focus groups to describe externalizing behaviors that they have both witnessed and personally struggled with in the classroom, discuss the perceived causes of these behaviors, and their suggestions for improving school culture to reduce these behavior manifestations in the classroom. Two major categories of behavior were identified, including: “anger emotions” and “aggressive actions.” Students described the causes of behavior as, “environmental influences” and “triggers.” The most common solutions that students gave to reduce externalizing behaviors in school settings included “encouraging respect of others” and “improving behavior management to enhance student engagement.” An additional solution suggested by the students included the “monarch room as support.” The Monarch Room is an alternative intervention to traditional suspension/expulsion polices that provides students in need of specific emotional support an opportunity to redirect/de-escalate externalizing behavior or mood in the school setting. This study highlights the need for trauma-informed approaches in school settings, and the importance of the inclusion of a youth voice in developing and implementing these intervention models

    Geriatric pharmacotherapy : optimisation through integrated approach in the hospital setting

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    Since older patients are more vulnerable to adverse drug-related events, there is a need to ensure appropriate prescribing in these patients in order to prevent misuse, overuse and underuse of drugs. Different tools and strategies have been developed to reduce inappropriate prescribing; the available measures can be divided into medication assessment tools, and speciïŹc interventions to reduce inappropriate prescribing. Implicit criteria of inappropriate prescribing focus on appropriate dosing, search for drug-drug interactions, and increase adherence. Explicit criteria are consensus-based standards focusing on drugs and diseases and include lists of drugs to avoid in general or lists combining drugs with clinical data. These criteria take into consideration differences between patients, and stand for a medication review, by using a systematic approach. Different types of interventions exist in order to reduce inappropriate prescribing in older patients, such as: educational interventions, computerized decision support systems, pharmacist-based interventions, and geriatric assessment. The effects of these interventions have been studied, sometimes in a multifaceted approach combining different techniques, and all types seem to have positive effects on appropriateness of prescribing. Interdisciplinary teamwork within the integrative pharmaceutical care is important for improving of outcomes and safety of drug therapy. The pharmaceutical care process consists offour steps, which are cyclic for an individual patient. These steps are pharmaceutical anamnesis, medication review, design and follow-up of a pharmaceutical care plan. A standardized approach is necessary for the adequate detection and evaluation of drug-related problems. Furthermore, it is clear that drug therapy should be reviewed in-depth, by having full access to medical records, laboratory values and nursing notes. Although clinical pharmacists perform the pharmaceutical care process to manage the patient’s drug therapy in every day clinical practice, the physician takes the ultimate responsibility for the care of the patient in close collaboration with nurses

    Effect of Thermal Treatments on the Transduction Behaviors of Conductometric Hydrogen Gas Sensors Integrated with HCl-Doped Polyaniline Nanofibers

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    We present the effect of thermal treatments on the transduction behaviors of HCl-doped polyaniline (PANI) nanofibers integrated in conductometric devices upon exposure to 1% H2 (carried by N2). After drying in N2 at 25ÂșC for 12 hours, devices showed a ~10% decrease in electrical resistance upon exposure to 1% H2. However, devices subject to 12-hour drying in N2 at 25ÂșC followed by further thermal treatments in N2 at 100ÂșC, 164ÂșC or 200ÂșC for 30 minutes showed different transduction behaviors. Specifically, devices subject to thermal treatments at 100ÂșC and 164ÂșC showed a decrease in electrical resistance by ~7% and \u3c0.5%, respectively. More interestingly, the device subject to thermal treatment at 200ÂșC showed a transduction behavior with opposite polarity, i.e. a ~5% increase in electrical resistance upon exposure to 1% H2. SEM, FTIR and TGA were employed to investigate the effect of thermal treatments on the morphology and chemical characteristics of HCl-doped polyaniline nanofibers. The results indicated that the change in the devices? interesting transduction behaviors might be related to the thermal treatment effects on the HCl-doped PANI nanofibers in (i) removal of adsorbed water, and (ii) crosslinking and/or degradation of polymer backbones
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