1,802 research outputs found
Undergraduate Knowledge of School Psychology and the Effects of Presentation on Graduate and Career Pursuit
With the increasing national demand for credentialed school psychologists, it is essential that every effort be made to recruit qualified individuals into the field of school psychology. This paper describes the important role and function of the school psychologist. Research demonstrating the present and future need for school psychological services is presented. Literature investigating several factors that contribute to the gap between supply and demand is reviewed. An intervention is presented based on the recommendations of the reviewed research. A brief informational presentation on school psychology, in conjunction with distributed materials about the profession, was assessed with a retrospective pretest-posttest design. The intervention was shown to increase undergraduates\u27 knowledge of school psychological service, the amount of information they had on school psychology as a potential career choice, and the amount of information they had on graduate training in school psychology. The intervention also significantly increased the number of students considering graduate training in school psychology. The majority of the students indicated that they planned on seeking more information about school psychology. The intervention was deemed relevant, interesting, and informative by the participants
Spatial-Temporal Imaging of Anisotropic Photocarrier Dynamics in Black Phosphorus
As an emerging single elemental layered material with a low symmetry in-plane
crystal lattice, black phosphorus (BP) has attracted significant research
interest owing to its unique electronic and optoelectronic properties,
including its widely tunable bandgap, polarization dependent photoresponse and
highly anisotropic in-plane charge transport. Despite extensive study of the
steady-state charge transport in BP, there has not been direct characterization
and visualization of the hot carriers dynamics in BP immediately after
photoexcitation, which is crucial to understanding the performance of BP-based
optoelectronic devices. Here we use the newly developed scanning ultrafast
electron microscopy (SUEM) to directly visualize the motion of photo-excited
hot carriers on the surface of BP in both space and time. We observe highly
anisotropic in-plane diffusion of hot holes, with a 15-times higher diffusivity
along the armchair (x-) direction than that along the zigzag (y-) direction.
Our results provide direct evidence of anisotropic hot carrier transport in BP
and demonstrate the capability of SUEM to resolve ultrafast hot carrier
dynamics in layered two-dimensional materials.Comment: 21 pages, 6 figure
Grand Challenges in School Social Work: Collaboration and Constraint in School Social Workers’ Sexuality Support for Children with Disabilities
Children with disabilities (CWD) face challenges to the development of their sexuality, in part due to a lack of appropriate, tailored sexual education in schools, role ambiguity regarding provision of sexual health services, and widespread discomfort with the topic. However, CWD have unique sexual health needs, an increased vulnerability to sexual and other forms of violence, and desire for skills and knowledge to build relationships. Using a phenomenological lens, authors conducted semistructured interviews with eight school social workers to understand how they are working with other professionals to support sexual and relational health of CWD (ages three to 11). Results indicate that school social workers collaborated with other professionals, although they also described multiple contexts in which other professionals had sole responsibility for sexual education and deferred to their expertise. Role ambiguity, policy restrictions, proscribed roles, and discomfort with the topic limited provision of needed services. Findings can assist school social workers seeking to build interdisciplinary collaboration, reduce role ambiguity, foster comfortable environments, and advocate for appropriate formats to support the sexual and relational health and well-being of CWD. They also suggest areas for policy change so that sexual support services are inclusive of all youths
Near-Earth asteroid (3200) Phaethon. Characterization of its orbit, spin state, and thermophysical parameters
The near-Earth asteroid (3200) Phaethon is an intriguing object: its
perihelion is at only 0.14 au and is associated with the Geminid meteor stream.
We aim to use all available disk-integrated optical data to derive a reliable
convex shape model of Phaethon. By interpreting the available space- and
ground-based thermal infrared data and Spitzer spectra using a thermophysical
model, we also aim to further constrain its size, thermal inertia, and visible
geometric albedo. We applied the convex inversion method to the new optical
data obtained by six instruments and to previous observations. The convex shape
model was then used as input for the thermophysical modeling. We also studied
the long-term stability of Phaethon's orbit and spin axis with a numerical
orbital and rotation-state integrator. We present a new convex shape model and
rotational state of Phaethon: a sidereal rotation period of 3.603958(2) h and
ecliptic coordinates of the preferred pole orientation of (319,
39) with a 5 uncertainty. Moreover, we derive its size
(=5.10.2 km), thermal inertia (=600200 J m
s K), geometric visible albedo
(=0.1220.008), and estimate the macroscopic surface
roughness. We also find that the Sun illumination at the perihelion passage
during the past several thousand years is not connected to a specific area on
the surface, which implies non-preferential heating.Comment: Astronomy and Astrophysics. In pres
Structural Attributes of the Hypogeous Holoparasite Hydnora Triceps Drège & Meyer (Hydnoraceae)
The morphology of the hypogeous root holoparasite Hydnora triceps is highly reduced, and as with many holoparasites, the vegetative body is difficult to interpret. The vegetative body of H. triceps has been historically considered a pilot root studded with lateral appendages known as haustorial roots. We found the vegetative body of H. triceps to consist of a rhizome with a thickened root-cap-like structure that covered a vegetative shoot apical meristem. From the apical meristem, procambial strands originated and developed into endarch collateral vascular bundles arranged radially around a pith without an interfascicular cambium. Xylem vessels had scalariform pitting and simple perforation plates. A continuous periderm without root hairs was observed. Increase in girth was attributed to cork and fascicular cambia. Haustorial roots or bumps on the surface of the vegetative body were exogenous, contained meristems and were the origins of vegetative branching, budding, and haustoria. The haustoria of H. triceps were cylindrical and penetrated the host root stele. Phloem and xylem elements were observed within the endophyte, and direct xylem to host-xylem contacts were observed. The arrangement of vascular tissues and xylem anatomy of H. triceps are likely plesiomorphic features in light of Hydnoraceae\u27s placement in the Piperales
Photo-excited hot carrier dynamics in hydrogenated amorphous silicon imaged by 4D electron microscopy
Charge carrier dynamics in amorphous semiconductors has been a topic of intense research that has been propelled by modern applications in thin-film solar cells, transistors and optical sensors. Charge transport in these materials differs fundamentally from that in crystalline semiconductors owing to the lack of long-range order and high defect density. Despite the existence of well-established experimental techniques such as photoconductivity time-of-flight and ultrafast optical measurements, many aspects of the dynamics of photo-excited charge carriers in amorphous semiconductors remain poorly understood. Here, we demonstrate direct imaging of carrier dynamics in space and time after photo-excitation in hydrogenated amorphous silicon (a-Si:H) by scanning ultrafast electron microscopy (SUEM). We observe an unexpected regime of fast diffusion immediately after photoexcitation, together with spontaneous electron–hole separation and charge trapping induced by the atomic disorder. Our findings demonstrate the rich dynamics of hot carrier transport in amorphous semiconductors that can be revealed by direct imaging based on SUEM
Induction of T Lymphocytes Specific for Bovine Viral Diarrhea Virus in Calves with Maternal Antibody
Passive antibody to bovine viral diarrhea virus (BVDV) acquired through colostrum intake may interfere with the development of a protective immune response by calves to this virus. The objective of this study was to determine if calves, with a high level of maternal antibody to bovine viral diarrhea virus (BVDV), develop CD4+, CD8+, or γδ T lymphocyte responses to BVDV in the absence of a measurable humoral immune response. Colostrum or milk replacer fed calves were challenged with virulent BVDV at 2-5 weeks of age and/or after maternal antibody had waned. Calves exposed to BVDV while passive antibody levels were high did not mount a measurable humoral immune response to BVDV. However, compared to nonexposed animals, these animals had CD4+, CD8+, and γδ T lymphocytes that were activated by BVDV after exposure to in vitro BVDV. The production of IFNγ by lymphocytes after in vitro BVDV exposure was also much greater in lymphocytes from calves exposed to BVDV in the presence of maternal antibody compared to the nonexposed calves. These data indicate that calves exposed to BVDV while maternal antibody levels are high can develop antigen specific CD4+, CD8+, and γδ T lymphocytes in the absence of an active antibody response. A manuscript presented separately demonstrates that the calves with T lymphocytes specific for BVDV in this study were also protected from virulent BVDV genotype 2 challenge after maternal antibody became undetectable
First-principles mode-by-mode analysis for electron-phonon scattering channels and mean free path spectra in GaAs
We present a first-principles framework to investigate the electron
scattering channels and transport properties for polar material by combining
the exact solution of linearized electron-phonon (e-ph) Boltzmann transport
equation in its integral-differential form associated with the e-ph coupling
matrices obtained from polar Wannier interpolation scheme. No ad hoc parameter
is required throughout this calculation, and GaAs, a well-studied polar
material, is used as an example to demonstrate this method. In this work, the
long-range and short-range contributions as well as the intravalley and
intervalley transitions in the e-ph interactions (EPIs) have been
quantitatively addressed. Promoted by such mode-by-mode analysis, we find that
in GaAs, the piezoelectric scattering is comparable to deformation-potential
scattering for electron scatterings by acoustic phonons in EPI even at room
temperature and makes a significant contribution to mobility. Furthermore, we
achieved good agreements with experimental data for the mobility, and
identified that electrons with mean free paths between 130 and 210 nm
contribute dominantly to the electron transport at 300 K. Such information
provides deeper understandings on the electron transport in GaAs, and the
presented framework can be readily applied to other polar materials
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