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Defects in semiconductors lead to deleterious effects in electron devices, but identifying their physical sources can be difficult. An example of this in gallium nitride (GaN) high electron mobility transistors is the well-known trap state located at approximately EC-0.57 eV. This trap is strongly correlated with output power degradation and reliability issues, but despite two decades of study, its specific physical source is still unknown. To address this long-standing question, two complementary nm-resolution characterization techniques—scanning probe deep level transient spectroscopy (SP-DLTS) and electron channeling contrast imaging (ECCI)—were used to spatially map the lateral distribution of these traps and to image and characterize their relation to residual threading dislocations within NH3-MBE-grown n-type GaN. Direct comparison of the SP-DLTS and ECCI measurements on the same sample region reveals highly localized concentrations of EC-0.57 eV traps that are spatially correlated with pure edge type threading dislocations in the GaN, but not with mixed and/or screw type dislocations, indicating that the specific dislocation character is a defining factor for this particular defect level. This work demonstrates the efficacy of combining these two techniques to obtain energy-, location-, and structure-resolved characterization of defects in a functional device structure. [ABSTRACT FROM AUTHOR]

Background and Purpose: The purpose of this study was to use single-subject research methods, combined with social validation procedures, as part of an evaluation/intervention process exploring the effects of adapted switch-operated devices on self-initiated behaviors of a 6-year-old child with profound multiple disabilities. Method: A single-subject withdrawal design with multiple phases, including one alternating treatments phase, was used to investigate the participant's ability to perform selective, voluntary motions as indicators of contingency awareness and preferences. Social validity also was assessed. Results: The child demonstrated the ability to use two switch sites to activate adapted switch-operated devices when a preferred stimulus was contingent on a specific motor action, and she demonstrated the ability to communicate preferences as indicated by more frequent switch activations for one consequence than for a second consequence. Social validity results indicated that both the parents and school personnel generally viewed the evaluation/intervention process as positive. Conclusions: Single-subject research methods, combined with social validation procedures, can be used effectively in the evaluation/intervention process for children with profound multiple disabilities. [ABSTRACT FROM AUTHOR]

The Peabody Gross Motor Scale is used to assess gross motor skills and often is employed in the process of qualifying children for special education and related services. Although this is a standardized test, two methods of scoring this assessment have been published. The purposes of this study were to determine if using the two scoring methods would result in differing raw scores, percentile ranks, z-scores, and developmental motor quotients, and if using one method as opposed to the other would affect children's scores to the point of altering their eligibility to receive special services. The results revealed that significant differences exist for all four types of scores and, depending upon the eligibility criteria employed, the method of scoring could have changed eligibility status for 8% to 9% of the subjects in this study. [ABSTRACT FROM AUTHOR]

Physical and occupational therapists play important roles in wheelchair prescription for children with disabilities. Matching a child's seating and functional needs with a particular power mobility device can be challenging, especially as more power wheelchair options become available. Information about potential performance in home and school settings cannot be inferred from manufacturer's basic descriptions of wheelchairs. In this article, we describe features of a newly available power wheelchair for children and young adults and also report on the evaluation of this wheelchair using a structured protocol to assess functional capacity. The focus of the study was the wheelchair's performance in commonly accessed environments. To allow evaluation of maximal performance of all features, an able-bodied child was the subject of this study. In this wheelchair, the subject was successful in performing indoor functional activities, maneuvering on smooth level surfaces, traversing rough terrain, and in negotiating curbs. [ABSTRACT FROM AUTHOR]

Bonding diamond to the back side of gallium nitride (GaN) electronics has been shown to improve thermal management in lateral devices; however, engineering challenges remain with the bonding process and characterizing the bond quality for vertical device architectures. Here, integration of these two materials is achieved by room-temperature compression bonding centimeter-scale GaN and a diamond die via an intermetallic bonding layer of Ti/Au. Recent attempts at GaN/diamond bonding have utilized a modified surface activation bonding (SAB) method, which requires Ar fast atom bombardment immediately followed by bonding within the same tool under ultrahigh vacuum (UHV) conditions. The method presented here does not require a dedicated SAB tool yet still achieves bonding via a room-temperature metal-metal compression process. Imaging of the buried interface and the total bonding area is achieved via transmission electron microscopy (TEM) and confocal acoustic scanning microscopy (C-SAM), respectively. The thermal transport quality of the bond is extracted from spatially resolved frequency-domain thermoreflectance (FDTR) with the bonded areas boasting a thermal boundary conductance of >100 MW/m 2 ·K. Additionally, Raman maps of GaN near the GaN-diamond interface reveal a low level of compressive stress, <80 MPa, in well-bonded regions. FDTR and Raman were coutilized to map these buried interfaces and revealed some poor thermally bonded areas bordered by high-stress regions, highlighting the importance of spatial sampling for a complete picture of bond quality. Overall, this work demonstrates a novel method for thermal management in vertical GaN devices that maintains low intrinsic stresses while boasting high thermal boundary conductances.

Nanostructured plasmonic-magnetic metamaterials have gained great research interest due to their enhanced magneto-optical coupling effects. Here, we report a complex three-phase nanocomposite design combining ferromagnetic CoFe 2 with plasmonic TiN and Au as a multifunctional hybrid metamaterial using either a cogrowth or a templated method. Via the first method of cogrowing three phases, three different morphologies of Au-CoFe 2 core-shell nanopillars were formed in the TiN matrix. Via the second method of sequential deposition of a TiN-Au seed layer and a TiN-CoFe 2 layer, highly ordered and uniform single-type core-shell nanopillars (i.e., the CoFe 2 shell with a Au core) form in the TiN matrix. Both cogrowth and templated growth TiN-CoFe 2 -Au hybrid systems exhibit excellent epitaxial quality, hyperbolic dispersion, magnetic anisotropy, and a magneto-optical coupling effect. This study provides an effective approach for achieving highly uniform multiphase vertically aligned nanocomposite structures with well-integrated optical, magnetic, and coupling properties.

Metamaterials present great potential in the applications of solar cells and nanophotonics, such as super lenses and other meta devices, owing to their superior optical properties. In particular, hyperbolic metamaterials (HMMs) with exceptional optical anisotropy offer improved manipulation of light-matter interactions as well as a divergence in the density of states and thus show enhanced performances in related fields. Recently, the emerging field of oxide-metal vertically aligned nanocomposites (VANs) suggests a new approach to realize HMMs with flexible microstructural modulations. In this work, a new oxide-metal metamaterial system, CeO 2 -Au, has been demonstrated with variable Au phase morphologies from nanoparticle-in-matrix (PIM), nanoantenna-in-matrix, to VAN. The effective morphology tuning through deposition background pressure, and the corresponding highly tunable optical performance of three distinctive morphologies, were systematically explored and analyzed. A hyperbolic dispersion at high wavelength has been confirmed in the nano-antenna CeO 2 -Au thin film, proving this system as a promising candidate for HMM applications. More interestingly, a new and abnormal in-plane epitaxy of Au nanopillars following the large mismatched CeO 2 matrix instead of the well-matched SrTiO 3 substrate, was discovered. Additionally, the tilting angle of Au nanopillars, α , has been found to be a quantitative measure of the balance between kinetics and thermodynamics during the depositions of VANs. All these findings provide valuable information in the understanding of the VAN formation mechanisms and related morphology tuning.

Oxide-metal-based hybrid materials have gained great research interest in recent years owing to their potential for multifunctionality, property coupling, and tunability. Specifically, oxide-metal hybrid materials in a vertically aligned nanocomposite (VAN) form could produce pronounced anisotropic physical properties, e.g. , hyperbolic optical properties. Herein, self-assembled HfO 2 -Au nanocomposites with ultra-fine vertically aligned Au nanopillars (as fine as 3 nm in diameter) embedded in a HfO 2 matrix were fabricated using a one-step self-assembly process. The film crystallinity and pillar uniformity can be obviously improved by adding an ultra-thin TiN-Au buffer layer during the growth. The HfO 2 -Au hybrid VAN films show an obvious plasmonic resonance at 480 nm, which is much lower than the typical plasmonic resonance wavelength of Au nanostructures, and is attributed to the well-aligned ultra-fine Au nanopillars. Coupled with the broad hyperbolic dispersion ranging from 1050 nm to 1800 nm in wavelength, and unique dielectric HfO 2 , this nanoscale hybrid plasmonic metamaterial presents strong potential for the design of future integrated optical and electronic switching devices.

Multiferroic materials are an interesting functional material family combining two ferroic orderings, e.g. , ferroelectric and ferromagnetic orderings, or ferroelectric and antiferromagnetic orderings, and find various device applications, such as spintronics, multiferroic tunnel junctions, etc. Coupling multiferroic materials with plasmonic nanostructures offers great potential for optical-based switching in these devices. Here, we report a novel nanocomposite system consisting of layered Bi 1.25 AlMnO 3.25 (BAMO) as a multiferroic matrix and well dispersed plasmonic Au nanoparticles (NPs) and demonstrate that the Au nanoparticle morphology and the nanocomposite properties can be effectively tuned. Specifically, the Au particle size can be tuned from 6.82 nm to 31.59 nm and the 6.82 nm one presents the optimum ferroelectric and ferromagnetic properties and plasmonic properties. Besides the room temperature multiferroic properties, the BAMO-Au nanocomposite system presents other unique functionalities including localized surface plasmon resonance (LSPR), hyperbolicity in the visible region, and magneto-optical coupling, which can all be effectively tailored through morphology tuning. This study demonstrates the feasibility of coupling single phase multiferroic oxides with plasmonic metals for complex nanocomposite designs towards optically switchable spintronics and other memory devices., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Heteroepitaxy of β-phase gallium oxide (β-Ga 2 O 3 ) thin films on foreign substrates shows promise for the development of next-generation deep ultraviolet solar blind photodetectors and power electronic devices. In this work, the influences of the film thickness and crystallinity on the thermal conductivity of (2̅01)-oriented β-Ga 2 O 3 heteroepitaxial thin films were investigated. Unintentionally doped β-Ga 2 O 3 thin films were grown on c -plane sapphire substrates with off-axis angles of 0° and 6° toward ⟨112̅0⟩ via metal-organic vapor phase epitaxy (MOVPE) and low-pressure chemical vapor deposition. The surface morphology and crystal quality of the β-Ga 2 O 3 thin films were characterized using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The thermal conductivities of the β-Ga 2 O 3 films were measured via time-domain thermoreflectance. The interface quality was studied using scanning transmission electron microscopy. The measured thermal conductivities of the submicron-thick β-Ga 2 O 3 thin films were relatively low as compared to the intrinsic bulk value. The measured thin film thermal conductivities were compared with the Debye-Callaway model incorporating phononic parameters derived from first-principles calculations. The comparison suggests that the reduction in the thin film thermal conductivity can be partially attributed to the enhanced phonon-boundary scattering when the film thickness decreases. They were found to be a strong function of not only the layer thickness but also the film quality, resulting from growth on substrates with different offcut angles. Growth of β-Ga 2 O 3 films on 6° offcut sapphire substrates was found to result in higher crystallinity and thermal conductivity than films grown on on-axis c -plane sapphire. However, the β-Ga 2 O 3 films grown on 6° offcut sapphire exhibit a lower thermal boundary conductance at the β-Ga 2 O 3 /sapphire heterointerface. In addition, the thermal conductivity of MOVPE-grown (2̅01)-oriented β-(Al x Ga 1- x ) 2 O 3 thin films with Al compositions ranging from 2% to 43% was characterized. Because of phonon-alloy disorder scattering, the β-(Al x Ga 1- x ) 2 O 3 films exhibit lower thermal conductivities (2.8-4.7 W/m·K) than the β-Ga 2 O 3 thin films. The dominance of the alloy disorder scattering in β-(Al x Ga 1- x ) 2 O 3 is further evidenced by the weak temperature dependence of the thermal conductivity. This work provides fundamental insight into the physical interactions that govern phonon transport within heteroepitaxially grown β-phase Ga 2 O 3 and (Al x Ga 1- x ) 2 O 3 thin films and lays the groundwork for the thermal modeling and design of β-Ga 2 O 3 electronic and optoelectronic devices.

Medical educators have not reached widespread agreement on core content for a U.S. medical school curriculum. As a first step toward addressing this, five U.S. medical schools formed the Robert Wood Johnson Foundation Reimagining Medical Education collaborative to define, create, implement, and freely share core content for a foundational medical school course on microbiology and immunology. This proof-of-concept project involved delivery of core content to preclinical medical students through online videos and class-time interactions between students and facilitators. A flexible, modular design allowed four of the medical schools to successfully implement the content modules in diverse curricular settings. Compared with the prior year, student satisfaction ratings after implementation were comparable or showed a statistically significant improvement. Students who took this course at a time point in their training similar to when the USMLE Step 1 reference group took Step 1 earned equivalent scores on National Board of Medical Examiners-Customized Assessment Services microbiology exam items. Exam scores for three schools ranged from 0.82 to 0.84, compared with 0.81 for the national reference group; exam scores were 0.70 at the fourth school, where students took the exam in their first quarter, two years earlier than the reference group. This project demonstrates that core content for a foundational medical school course can be defined, created, and used by multiple medical schools without compromising student satisfaction or knowledge. This project offers one approach to collaboratively defining core content and designing curricular resources for preclinical medical school education that can be shared.

Phenomenon: The learning environment is the physical, social, and psychological context in which a student learns. A supportive learning environment contributes to student well-being and enhances student empathy, professionalism, and academic success, whereas an unsupportive learning environment may lead to burnout, exhaustion, and cynicism. Student perceptions of the medical school learning environment may change over time and be associated with students' year of training and may differ significantly depending on the student's gender or race/ethnicity. Understanding the changes in perceptions of the learning environment related to student characteristics and year of training could inform interventions that facilitate positive experiences in undergraduate medical education., Approach: The Medical School Learning Environment Survey (MSLES) was administered to 4,262 students who matriculated at one of 23 U.S. and Canadian medical schools in 2010 and 2011. Students completed the survey at the end of each year of medical school as part of a battery of surveys in the Learning Environment Study. A mixed-effects longitudinal model, t tests, Cohen's d effect size, and analysis of variance assessed the relationship between MSLES score, year of training, and demographic variables., Findings: After controlling for gender, race/ethnicity, and school, students reported worsening perceptions toward the medical school learning environment, with the worst perceptions in the 3rd year of medical school as students begin their clinical experiences, and some recovery in the 4th year after Match Day. The drop in MSLES scores associated with the transition to the clinical learning environment (-0.26 point drop in addition to yearly change, effect size = 0.52, p < .0001) is more than 3 times greater than the drop between the 1st and 2nd year (0.07 points, effect size = 0.14, p < .0001). The largest declines were from items related to work-life balance and informal student relationships. There was some, but not complete, recovery in perceptions of the medical school learning environment in the 4th year. Insights: Perceptions of the medical school learning environment worsen as students continue through medical school, with a stronger decline in perception scores as students' transition to the clinical learning environment. Students reported the greatest drop in finding time for outside activities and students helping one another in the 3rd year. Perceptions differed based on gender and race/ethnicity. Future studies should investigate the specific features of medical schools that contribute most significantly to student perceptions of the medical school learning environment, both positive and negative, to pinpoint potential interventions and improvements.

Problem: Medical students often struggle to appreciate the clinical relevance of material taught in the preclinical years. The authors believe videos could be effectively used to interweave a patient's illness script with foundational basic science concepts., Approach: In collaboration with four other U.S. medical schools, educators at the Stanford University School of Medicine created 36 short, animated, patient-centered springboard videos (third-person, narrated accounts of authentic patient cases conveying foundational pathophysiology) in 2014. The videos were used to introduce students to 36 content modules, created as part of a microbiology, immunology, and infectious diseases curriculum. The videos were created with input from faculty content experts and in some cases medical students, and were piloted using a flipped classroom pedagogical approach in January 2015-June 2016., Outcomes: Student feedback from course evaluations and focus groups was analyzed using a mixed-methods approach. On the course evaluations, the majority of students rated the patient-centered videos positively, and the majority of comments on the videos were positive, highlighting both enhanced engagement and enhanced learning and retention. Comments from focus groups mirrored the course evaluation comments and highlighted different usage patterns for the videos., Next Steps: The authors will continue to gather and analyze data from schools using the videos as part of their core preclinical curriculum, and will produce similar videos for use in other areas of undergraduate medical education. These videos could support students' review of content taught previously and be repurposed for use in continuing and graduate medical education, as well as patient education.

Purpose: To measure trainees' exposure to negative and positive role-modeling for responding to medical errors and to examine the association between that exposure and trainees' attitudes and behaviors regarding error disclosure., Method: Between May 2011 and June 2012, 435 residents at two large academic medical centers and 1,187 medical students from seven U.S. medical schools received anonymous, electronic questionnaires. The questionnaire asked respondents about (1) experiences with errors, (2) training for responding to errors, (3) behaviors related to error disclosure, (4) exposure to role-modeling for responding to errors, and (5) attitudes regarding disclosure. Using multivariate regression, the authors analyzed whether frequency of exposure to negative and positive role-modeling independently predicted two primary outcomes: (1) attitudes regarding disclosure and (2) nontransparent behavior in response to a harmful error., Results: The response rate was 55% (884/1,622). Training on how to respond to errors had the largest independent, positive effect on attitudes (standardized effect estimate, 0.32, P < .001); negative role-modeling had the largest independent, negative effect (standardized effect estimate, -0.26, P < .001). Positive role-modeling had a positive effect on attitudes (standardized effect estimate, 0.26, P < .001). Exposure to negative role-modeling was independently associated with an increased likelihood of trainees' nontransparent behavior in response to an error (OR 1.37, 95% CI 1.15-1.64; P < .001)., Conclusions: Exposure to role-modeling predicts trainees' attitudes and behavior regarding the disclosure of harmful errors. Negative role models may be a significant impediment to disclosure among trainees.

OBJECTIVE. The purpose of this study was to examine the effects of partnerships between people with disabilities and service dogs on functional performance and social interaction. METHOD. A single-subject, alternating treatment design was used. The participants were 3 women with mobility challenges who owned service dogs. For each participant, time and perceived amount of effort for two tasks were measured for functional performance. Interaction and satisfaction levels were measured for social interactions. RESULTS. Primary findings were that service dog partnerships decreased performance time for four of the six tasks, decreased effort for five of the six tasks, increased social interactions for 2 of the participants, and increased levels of satisfaction with social interactions for all participants. CONCLUSION. For adult women with mobility challenges, service dog partnerships may contribute to energy conservation through decreased time and effort required to complete some tasks and may increase social interactions., (Copyright © 2014 by the American Occupational Therapy Association, Inc.)

OBJECTIVE. This retrospective study explored sensory processing characteristics in preschool-age children with autism spectrum disorders (ASD); the relationships between sensory processing and problem behavior, adaptive behavior, and cognitive function; and the differences in sensory processing between two subgroups (autism and pervasive developmental disorder-not otherwise specified). METHOD. Study measures included the Short Sensory Profile (SSP), Aberrant Behavior Checklist-Community, Vineland Adaptive Behavior Scales, and Mullen Scales of Early Learning. RESULTS. Most of the children with ASD had sensory processing challenges, and a significant relationship was found between SSP total scores and problem behavior scores; however, no significant relationships were found between SSP total scores and adaptive behavior and cognitive functioning. Although all the children had low Vineland scores, approximately one-quarter of the children had typical SSP scores. No significant differences in SSP scores were found between the subgroups. CONCLUSION. The findings highlight the importance of comprehensive evaluations for children with ASD., (Copyright © 2012 by the American Occupational Therapy Association, Inc.)

Medical schools continually evolve their curricula to keep students abreast of advances in basic, translational, and clinical sciences. To provide feedback to educators, critical evaluation of the effectiveness of these curricular changes is necessary. This article describes a method of curriculum evaluation, called "empowerment evaluation," that is new to medical education. It mirrors the increasingly collaborative culture of medical education and offers tools to enhance the faculty's teaching experience and students' learning environments. Empowerment evaluation provides a method for gathering, analyzing, and sharing data about a program and its outcomes and encourages faculty, students, and support personnel to actively participate in system changes. It assumes that the more closely stakeholders are involved in reflecting on evaluation findings, the more likely they are to take ownership of the results and to guide curricular decision making and reform. The steps of empowerment evaluation include collecting evaluation data, designating a "critical friend" to communicate areas of potential improvement, establishing a culture of evidence, encouraging a cycle of reflection and action, cultivating a community of learners, and developing reflective educational practitioners. This article illustrates how stakeholders used the principles of empowerment evaluation to facilitate yearly cycles of improvement at the Stanford University School of Medicine, which implemented a major curriculum reform in 2003-2004. The use of empowerment evaluation concepts and tools fostered greater institutional self-reflection, led to an evidence-based model of decision making, and expanded opportunities for students, faculty, and support staff to work collaboratively to improve and refine the medical school's curriculum.

Objective: This study describes the sensory-processing and behavior profiles of a clinic-referred sample of children with fetal alcohol spectrum disorders (FASD) and examines the relationship between sensory processing and behavior., Methods: Outcomes on the Short Sensory Profile (SSP) and Child Behavior Checklist (CBCL) for 44 children, ages 5 to 10 years, were assessed and compared using retrospective data analysis., Results: A high proportion of the children demonstrated deficits in sensory processing and problem behaviors as measured by the SSP and the CBCL. Moreover, the correlation between the SSP and CBCL total scores (r = -.72) was significant., Conclusion: Results provide evidence that children with FASD demonstrate problem behaviors and sensory-processing impairments as reported by parents and that sensory-processing deficits co-occur with problem behaviors at a high rate in this population. This finding suggests that deficits in sensory processing may affect the ability of children with FASD to respond adaptively to their environments.

Objective: Interrater agreement and construct validity of the Revised Knox Preschool Play Scale (RKPPS) were examined., Method: Two separately trained raters evaluated 38 typically developing children, ages 36 to 72 months. For each child, the raters observed two 15-min free-play sessions., Results: For the overall play age, the scores of the two raters were within 8 months of each other 86.8% of the time; for the 4 dimension scores, they were within 12 months of each other 91.7% to 100% of the time; and for the 12 category scores, they were within one age level of each other 81.8% to 100% of the time. Construct validity results showed a general match between the children's chronological ages and their overall play age scores., Conclusions: Findings suggest that two raters can score the RKPPS with some consistency and that scores on this measure progress developmentally, thus supporting its construct validity.

Purpose: This study examined satisfaction with communicative participation as reported by adults with multiple sclerosis (MS)., Method: Eight community-dwelling adults with MS participated in semi-structured interviews. They were asked to discuss their satisfaction with their communication in a variety of situations. Interviews were analyzed using a constant comparative method of qualitative description., Results: Themes derived included: Comfort, consisting of Ease and Confidence; Success of the Outcome, including Function is Achieved and A Connection is Made; and Personal Meaning of Participation, including Personal Preferences, Comparison with the Past, and Thinking about One's Own Communication., Conclusions: Participants described multiple facets of satisfaction with communicative participation. Some of the dimensions were similar to those in existing assessment instruments such as levels of ease or difficulty with performance. Participants did not talk about frequency of activities as a key part of their satisfaction. Implications for identifying intervention targets and treatment outcome measurements are provided., Learning Outcomes: The reader should be able to: 1) define communicative participation and identify key elements of this construct; 2) identify the issues that were most relevant to satisfaction with communicative participation with participants with MS; and 3) identify reasons for greater emphasis on the subjective viewpoint of people with communication disorders in measurement of treatment outcomes.

Objective: The purpose of this study was to investigate the effects of therapy balls as seating on in-seat behavior and legible word productivity of students with attention deficit hyperactivity disorder (ADHD). Additionally, social validity was assessed to evaluate teacher and student opinions regarding the intervention., Method: A single subject, A-B-A-B interrupted time series design was employed across 3 students (2 males, 1 female) with ADHD. The study was conducted in a 4th grade inclusive classroom during daily language arts. During phases 1 and 3, the 3 participants and all other class members sat on chairs (in-seat on chair); during phases 2 and 4, everyone sat on therapy balls (in-seat on ball). Dependent variables were in-seat behavior and legible word productivity. Data were graphed and visually analyzed for differences between phases., Results: Results demonstrated increases in in-seat behavior and legible word productivity for the students with ADHD when seated on therapy balls. Social validity findings indicated that generally the teacher and students preferred therapy balls., Conclusion: This study provides evidence that use of therapy balls for students with ADHD may facilitate in-seat behavior and legible word productivity.