580 research outputs found
The Impact of Career and Technical Education Programs on At-Risk Secondary Students
As the number of youth at risk for educational failure has increased, so has the debate over the appropriate nature of career and technical education (CTE) programs for such youth. The purpose of this study was to gain an understanding about the manner in which CTE programs within vocational schools affected secondary students at risk for educational failure. The educational theories of Pestalozzi, Dewey, and Rousseau served as the conceptual framework for this study by supporting the development of students\u27 intellectual, social, and emotional growth through hands-on activities rather than traditional rote learning. Data for this case study were collected through interviews and observations from 9 purposefully selected students enrolled in vocational school CTE programs. Qualitative strategies of memoing and coding supported interpretative data analysis for this case study. The participants revealed that their CTE programs had a positive impact on their lives. Findings that emerged from this study centered on job security, hands-on learning, and personal growth. These findings provide important empirical evidence of the utility of CTE programs for at-risk students. This evidence contributes to positive social change by illuminating an alternative education setting that enables at-risk students to attain and maintain academic success. This evidence also holds promise for positive social change by guiding the efforts of education stakeholders in determining the appropriate educational placement for at-risk students, placements that will promote a sense of belonging rather than alienation
Mental representations of trait categoriesand their influences on person perception
Three studies explored mental representations of the organization of acts into traits, and how such mental representations influence person perception. Specifically, we investigated whether acts vary in their degree of trait-category membership (prototypicality), what determines an act\u27s prototypicality, and whether acts\u27 prototypicalities influence conclusions about observed acts. By drawing on research on prototypicality-based models of mental representations (Osherson, Smith, Wilkie, López, & Shafir, 1990), five hypotheses were proposed about the nature of mental representations of traits and how they influence person perception. In Study 1, subjects rated three aspects of several acts: how prototypical of the trait they are, how similar they are to other acts in the trait, and how extreme they are. Subjects showed substantial agreement on all three ratings. Additionally, an act\u27s similarity to other acts in the trait was predictive of how prototypical the act was, but the act\u27s extremity was a stronger predictor of its prototypicality. Study 2 investigated how the prototypicality of an actor\u27s observed acts influences person perception. Subjects were more willing to describe an actor\u27s acts with a trait when the acts were prototypical or similar to each other than when the acts were not prototypical or not similar to each other. Study 3 investigated the prototypicality of predicted acts. Results showed that predictions of acts were not influenced by the prototypicality of the predicted acts. Together, the three studies suggest that mental representations of traits are consensual and that they influence person perception
Water adsorption on vanadium oxide thin films in ambient relative humidity.
In this work, ambient pressure x-ray photoelectron spectroscopy (APXPS) is used to study the initial stages of water adsorption on vanadium oxide surfaces. V 2p, O 1s, C 1s, and valence band XPS spectra were collected as a function of relative humidity in a series of isotherm and isobar experiments. Experiments were carried out on two VO2 thin films on TiO2 (100) substrates, prepared with different surface cleaning procedures. Hydroxyl and molecular water surface species were identified, with up to 0.5 ML hydroxide present at the minimum relative humidity, and a consistent molecular water adsorption onset occurring around 0.01% relative humidity. The work function was found to increase with increasing relative humidity, suggesting that surface water and hydroxyl species are oriented with the hydrogen atoms directed away from the surface. Changes in the valence band were also observed as a function of relative humidity. The results were similar to those observed in APXPS experiments on other transition metal oxide surfaces, suggesting that H2O-OH and H2O-H2O surface complex formation plays an important role in the oxide wetting process and water dissociation. Compared to polycrystalline vanadium metal, these vanadium oxide films generate less hydroxide and appear to be more favorable for molecular water adsorption
Takayasu arteritis presenting as cerebral aneurysms in an 18 month old: A case report
<p>Abstract</p> <p>Background</p> <p>Central nervous system involvement occurs in as many as twenty percent of Takayasu arteritis cases. When central nervous system disease is present, it typically manifests as cerebral ischemia or stroke. There are rare reports of intracranial aneurysms in adults with Takayasu arteritis, but none in children.</p> <p>Case presentation</p> <p>We describe a case of Takayasu arteritis in an 18 month old girl who presented with a ruptured cerebral aneurysm. Full body magnetic resonance angiography revealed bilateral iliac, pelvic and intragluteal aneurysms, irregular terminal aorta, and stenotic renal arteries. Iliac vessel biopsy showed a lymphocytic infiltrate and giant cells localized to the internal elastica.</p> <p>Conclusion</p> <p>This case highlights cerebral aneurysm as a highly unusual initial manifestation of Takayasu arteritis and demonstrates the challenges of diagnosis, treatment, and assessment of response to therapy in TA in children.</p
Appropriate uses of EICAT protocol, data and classifications
The Environmental Impact Classification for Alien Taxa (EICAT) can be used to classify alien taxa according to the magnitude and type of their environmental impacts. The EICAT protocol, classifications of alien taxa using the protocol (EICAT classification) and the data underpinning classifications (EICAT data) are increasingly used by scientists and practitioners such as governments, NGOs and civil society for a variety of purposes. However, the properties of the EICAT protocol and the data it generates are not suitable for certain uses. Therefore, we present guidelines designed to clarify and facilitate the appropriate use of EICAT to tackle a broad range of conservation issues related to biological invasions, as well as to guide research and communication more generally. Here we address common misconceptions and give a brief overview of some key issues that all EICAT users need to be aware of to take maximal advantage of this resource. Furthermore, we give examples of the wide variety of ways in which the EICAT protocol, classifications and data can be and have been utilised and outline common errors and pitfalls to avoid
Electrostatic binding of polyanions using self-assembled multivalent (SAMul) ligand displays-structure-activity effects on DNA/heparin binding
This paper reports that modifying the ligands in self-assembled multivalent (SAMul) displays has an impact on apparent binding selectivity towards two nanoscale biological polyanions-heparin and DNA. For the nanostructures assayed here, spermidine ligands are optimal for heparin binding but spermine ligands are preferred for DNA. Probing subtle differences in such nanoscale binding interfaces is a significant challenge, and as such, several experimental binding assays-competition assays and isothermal calorimetry-are employed to confirm differences in affinity and provide thermodynamic insights. Given the dynamic nature and hierarchical binding processes involved in SAMul systems, we employed multiscale modelling to propose reasons for the origins of polyanion selectivity differences. The modelling results, when expressed in thermodynamic terms and compared with the experimental data, suggest that DNA is a shape-persistent polyanion, and selectivity originates only from ligand preferences, whereas heparin is more flexible and adaptive, and as such, actively reinforces ligand preferences. As such, this study suggests that inherent differences between polyanions may underpin subtle binding selectivity differences, and that even simple electrostatic interfaces such as these can have a degree of tunability, which has implications for biological control and regulation on the nanoscale
Functional profiling of single CRISPR/Cas9-edited human long-term hematopoietic stem cells.
In the human hematopoietic system, rare self-renewing multipotent long-term hematopoietic stem cells (LT-HSCs) are responsible for the lifelong production of mature blood cells and are the rational target for clinical regenerative therapies. However, the heterogeneity in the hematopoietic stem cell compartment and variable outcomes of CRISPR/Cas9 editing make functional interrogation of rare LT-HSCs challenging. Here, we report high efficiency LT-HSC editing at single-cell resolution using electroporation of modified synthetic gRNAs and Cas9 protein. Targeted short isoform expression of the GATA1 transcription factor elicit distinct differentiation and proliferation effects in single highly purified LT-HSC when analyzed with functional in vitro differentiation and long-term repopulation xenotransplantation assays. Our method represents a blueprint for systematic genetic analysis of complex tissue hierarchies at single-cell resolution
Modified Pediatric ASPECTS Correlates with Infarct Volume in Childhood Arterial Ischemic Stroke
Background and Purpose: Larger infarct volume as a percent of supratentorial brain volume (SBV) predicts poor outcome and hemorrhagic transformation in childhood arterial ischemic stroke (AIS). In perinatal AIS, higher scores on a modified pediatric version of the Alberta Stroke Program Early CT Score using acute MRI (modASPECTS) predict later seizure occurrence. The objectives were to establish the relationship of modASPECTS to infarct volume in perinatal and childhood AIS and to establish the interrater reliability of the score. Methods: We performed a cross sectional study of 31 neonates and 40 children identified from a tertiary care center stroke registry with supratentorial AIS and acute MRI with diffusion weighted imaging (DWI) and T2 axial sequences. Infarct volume was expressed as a percent of SBV using computer-assisted manual segmentation tracings. ModASPECTS was performed on DWI by three independent raters. The modASPECTS were compared among raters and to infarct volume as a percent of SBV. Results: ModASPECTS correlated well with infarct volume. Spearman rank correlation coefficients (ρ) for the perinatal and childhood groups were 0.76, p < 0.001 and 0.69, p < 0.001, respectively. Excluding one perinatal and two childhood subjects with multifocal punctate ischemia without large or medium sized vessel stroke, ρ for the perinatal and childhood groups were 0.87, p < 0.001 and 0.80, p < 0.001, respectively. The intraclass correlation coefficients for the three raters for the neonates and children were 0.93 [95% confidence interval (CI) 0.89–0.97, p < 0.001] and 0.94 (95% CI 0.91–0.97, p < 0.001), respectively. Conclusion: The modified pediatric ASPECTS on acute MRI can be used to estimate infarct volume as a percent of SBV with a high degree of validity and interrater reliability
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