5,774 research outputs found

    Overview of Attention Deficit Hyperactivity Disorder in Young Children

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    Attention deficit hyperactivity disorder (ADHD) is a complex disorder, which can be seen as a disorder of life time, developing in preschool years and manifesting symptoms (full and/or partial) throughout the adulthood; therefore, it is not surprising that there are no simple solutions. The aim of this paper is to provide a short and concise review which can be used to inform affected children and adults; family members of affected children and adults, and other medical, paramedical, non-medical, and educational professionals about the disorder. This paper has also tried to look into the process of how ADHD develops; what are the associated problems; and how many other children and adults are affected by such problems all over the world basically to understand ADHD more precisely in order to develop a better medical and or non-medical multimodal intervention plan. If preschool teachers and clinicians are aware of what the research tells us about ADHD, the varying theories of its cause, and which areas need further research, the knowledge will assist them in supporting the families of children with ADHD. By including information in this review about the connection between biological behavior, it is hoped that preschool teachers and clinicians at all levels will feel more confident about explaining to parents of ADHD children, and older ADHD children themselves about the probable causes of ADHD

    Differentiation-dependent Requirement of Tsix long non-coding RNA in Imprinted X-chromosome Inactivation

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    Imprinted X-inactivation is a paradigm of mammalian transgenerational epigenetic regulation resulting in silencing of genes on the paternally-inherited X-chromosome. The pre-programmed fate of the X-chromosomes is thought to be controlled in cis by the parent-of-origin-specific expression of two long non-coding RNAs, Tsix and Xist, in mice. Exclusive expression of Tsix from the maternal–X has implicated it as the instrument through which the maternal germline prevents inactivation of the maternal–X in the offspring. Here, we show that Tsix is dispensable for inhibiting Xist and X-inactivation in the early embryo and in cultured stem cells of extra-embryonic lineages. Tsix is instead required to prevent Xist expression as trophectodermal progenitor cells differentiate. Despite induction of wild-type Xist RNA and accumulation of histone H3-K27me3, many Tsix-mutant X-chromosomes fail to undergo ectopic X-inactivation. We propose a novel model of lncRNA function in imprinted X-inactivation that may also apply to other genomically imprinted loci

    D-brane Spectrum and K-theory Constraints of D=4, N=1 Orientifolds

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    We study the spectrum of stable BPS and non-BPS D-branes in Z_2 x Z_2 orientifolds for all choices of discrete torsion between the orbifold and orientifold generators. We compute the torsion K-theory charges in these D=4, N=1 orientifold models directly from worldsheet conformal field theory, and compare with the K-theory constraints obtained indirectly using D-brane probes. The K-theory torsion charges derived here provide non-trivial constraints on string model building. We also discuss regions of stability for non-BPS D-branes in these examples.Comment: 40 pages, 5 table

    Envelope Determinants of Equine Lentiviral Vaccine Protection

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    Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection. © 2013 Craigo et al

    eChirp: Measuring Available Bandwidth for the Internet Using Multiple Chirp Packet Trains

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    Measuring available bandwidth over a network path in the Internet is a challenging research problem. In this thesis we have studied this problem and developed a new technique called "eChirp". First, the effectiveness of pathChirp [1] is studied in terms of model performance of chirp packet train structure, actual bandwidth, queuing delay and excursion segmentation. Then we remodeled the chirp train structure. The eChirp can measure the available bandwidth over a network path efficiently and accurately with heavy and light load links. To measure the available bandwidth, the packet probing rate configuration used in pathChirp technique is modified by changing its chirp train structure. The modified structure uses multiple chirp trains (three trains) that provides better probing rate configuration and ultimately gives better bandwidth measurement. Per-packet available bandwidth is calculated using weighted average of per-packet bandwidth of three trains. We also determined the bounds of probing rate parameter which was questionable in pathChirp and affects the available bandwidth measurement accuracy. The eChirp technique has been experimented with numerous network path topologies with low and high link loads with CBR cross-traffic conditions using NS-2 simulated network and results are compared with most recent pathChirp technique. Simulation results show that the proposed eChirp technique is better than pathChirp scheme in terms of estimating available bandwidth

    In silico-designed lignin peroxidase from Phanerochaete chrysosporium shows enhanced acid stability for depolymerization of lignin

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    Background: The lignin peroxidase isozyme H8 from the white-rot fungus Phanerochaete chrysosporium (LiPH8) demonstrates a high redox potential and can efficiently catalyze the oxidation of veratryl alcohol, as well as the degradation of recalcitrant lignin. However, native LiPH8 is unstable under acidic pH conditions. This characteristic is a barrier to lignin depolymerization, as repolymerization of phenolic products occurs simultaneously at neutral pH. Because repolymerization of phenolics is repressed at acidic pH, a highly acid-stable LiPH8 could accelerate the selective depolymerization of recalcitrant lignin. Results: The engineered LiPH8 was in silico designed through the structural superimposition of surface-active site-harboring LiPH8 from Phanerochaete chrysosporium and acid-stable manganese peroxidase isozyme 6 (MnP6) from Ceriporiopsis subvermispora. Effective salt bridges were probed by molecular dynamics simulation and changes to Gibbs free energy following mutagenesis were predicted, suggesting promising variants with higher stability under extremely acidic conditions. The rationally designed variant, A55R/N156E-H239E, demonstrated a 12.5-fold increased half-life under extremely acidic conditions, 9.9-fold increased catalytic efficiency toward veratryl alcohol, and a 7.8-fold enhanced lignin model dimer conversion efficiency compared to those of native LiPH8. Furthermore, the two constructed salt bridges in the variant A55R/N156E-H239E were experimentally confirmed to be identical to the intentionally designed LiPH8 variant using X-ray crystallography (PDB ID: 6A6Q). Conclusion: Introduction of strong ionic salt bridges based on computational design resulted in a LiPH8 variant with markedly improved stability, as well as higher activity under acidic pH conditions. Thus, LiPH8, showing high acid stability, will be a crucial player in biomass valorization using selective depolymerization of lignin

    Is group cognitive behaviour therapy for postnatal depression evidence-based practice? A systematic review

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    Background: There is evidence that psychological therapies including cognitive behaviour therapy (CBT) may be effective in reducing postnatal depression (PND) when offered to individuals. In clinical practice, this is also implemented in a group therapy format, which, although not recommended in guidelines, is seen as a cost-effective alternative. To consider the extent to which group methods can be seen as evidence-based, we systematically review and synthesise the evidence for the efficacy of group CBT compared to currently used packages of care for women with PND, and we discuss further factors which may contribute to clinician confidence in implementing an intervention. Methods: Seventeen electronic databases were searched. All full papers were read by two reviewers and a third reviewer was consulted in the event of a disagreement on inclusion. Selected studies were quality assessed, using the Cochrane Risk of Bias Tool, were data extracted by two reviewers using a standardised data extraction form and statistically synthesised where appropriate using the fixed-effect inverse-variance method. Results: Seven studies met the inclusion criteria. Meta-analyses showed group CBT to be effective in reducing depression compared to routine primary care, usual care or waiting list groups. A pooled effect size of d = 0.57 (95% CI 0.34 to 0.80, p < 0.001) was observed at 10–13 weeks post-randomisation, reducing to d = 0.28 (95% CI 0.03 to 0.53, p = 0.025) at 6 months. The non-randomised comparisons against waiting list controls at 10–13 weeks was associated with a larger effect size of d = 0.94 (95% CI 0.42 to 1.47, p < 0.001). However due to the limitations of the available data, such as ill-specified definitions of the CBT component of the group programmes, these results should be interpreted with caution. Conclusions: Although the evidence available is limited, group CBT was shown to be effective. We argue, therefore, that there is sufficient evidence to implement group CBT, conditional upon routinely collected outcomes being benchmarked against those obtained in trials of individual CBT, and with other important factors such as patient preference, clinical experience, and information from the local context taken into account when making the treatment decision

    Web 2.0 technologies for effective knowledge management in organizations: a qualitative analysis

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    A new generation of Internet-based collaborative tools, commonly known as Web 2.0, has increased in popularity, availability, and power in the last few years (Kane and Fichman, 2009). Web 2.0 is a set of Internet-based applications that harness network effects by facilitating collaborative and participative computing (O'Reilly, 2006). Conceptually, Web 2.0--with its ability to combine traditional KM tools' features with social computing, where knowledge is evolved through social interactions (Parameswaran, 2007)--has been identified as an effective KM paradigm (Fitch, 2007; Mindel and Verma, 2006).With such a capability, Web 2.0 technology has the potential to address many of the KM challenges that organizations face (Minocha and Thomas, 2007; Wagner, 2006). While Web 2.0 has gained widespread popularity at the consumer level, it is still not well-understood how Web 2.0 can be effectively used for KM by enterprises. In our research, we address this critical gap in the literature by using a multiple-case research design. This dissertation examines how IT organizations use Web 2.0 technologies for Knowledge Management (KM) at the individual, project, and group level. We also investigate how the use of Web 2.0 technology for KM affects organization, group, project, and individual level outcomes. Using multiple case research design, this research provides examples of effective use of Web 2.0 for KM at the individual, project, group, and organization level. Using empirical data, this research also establishes a relationship between the uses of Web 2.0 for KM and its effects on individual, project, group, and organization levels. The extant literature has yet to examine such relationships

    ROLES OF SCHOOL DISTRICT COMPETITION AND POLITICAL INSTITUTIONS IN PUBLIC SCHOOL SPENDING AND STUDENT ACHIEVEMENT

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    Equity in school district spending, and equity and productive efficiency in educational outcomes are of paramount importance in the literature on K-12 public education in the US. The research on the effects of school choice (operationalized as inter-school district competition) and local political institutions on unequal school district spending and equity and productive efficiency in educational outcomes is not adequate. This dissertation fills several gaps in the literature by 1) extending the literature on the Public Choice, the Leviathan, the Consolidated Local Government, and the Reformism models that examines the interactive roles of local political institutions and school choice on equity in spending, productive efficiency and equity in student achievement in public schools in metropolitan areas; and 2) modeling the equity effects of school choice and political institutions on school district spending and student achievement. Fixed effects, instrumental variable fixed effects, Hausman-Taylor regression, and Multilevel Linear regression models are utilized on a uniquely compiled longitudinal dataset from several sources, including the Popularly Elected Officials Survey from the US Census Bureau, the Local Education Agency (School District) Longitudinal Finance Survey, the National Education Longitudinal Study (NELS: 1988-92), and the School District Demographics System from the National Center for Education Statistics. Results from fixed effects models lend support for interactive effects of political institutions and inter-school district competition on school district spending. Additive and interactive models do not robustly support the equity effects of inter-school district competition on school district spending. However, results from fixed effects and instrumental variable fixed effects models support the equity effects of political institutions on school district spending in some cases. School districts with more professional political institutions are also more equitable in public education spending. Results show that whereas inter-school district competition has productive efficiency effects on student achievement the political institutions do not. In terms of equity, the inter-school district competition and political institutions have differential effects on student achievement. In regard to the former, results imply that the increased inter-school district competition leads to inequity in students' 10th grade reading scores and 12th grade reading and math scores. In regard to the latter, results suggest that differences in political institutions across school districts lead to inequity in students' 10th and 12th grade reading and math scores. School districts with more professional political institutions also have more equitable student achievement. Student's reading and math scores are generally higher in comparatively higher income quintile school districts than those in comparatively lower income quintile school districts. These findings assume significance as they inform the policymakers in regard to why and how organizational and political contexts matter in bringing desirable educational outcomes. The policymakers can bring organizational and political changes in school districts for achieving the goal of more effective public education

    Multi-scale data fusion for surface metrology

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    The major trends in manufacturing are miniaturization, convergence of the traditional research fields and creation of interdisciplinary research areas. These trends have resulted in the development of multi-scale models and multi-scale surfaces to optimize the performance. Multi-scale surfaces that exhibit specific properties at different scales for a specific purpose require multi-scale measurement and characterization. Researchers and instrument developers have developed instruments that are able to perform measurements at multiple scales but lack the much required multi- scale characterization capability. The primary focus of this research was to explore possible multi-scale data fusion strategies and options for surface metrology domain and to develop enabling software tools in order to obtain effective multi-scale surface characterization, maximizing fidelity while minimizing measurement cost and time. This research effort explored the fusion strategies for surface metrology domain and narrowed the focus on Discrete Wavelet Frame (DWF) based multi-scale decomposition. An optimized multi-scale data fusion strategy ‘FWR method’ was developed and was successfully demonstrated on both high aspect ratio surfaces and non-planar surfaces. It was demonstrated that the datum features can be effectively characterized at a lower resolution using one system (Vision CMM) and the actual features of interest could be characterized at a higher resolution using another system (Coherence Scanning Interferometer) with higher capability while minimizing the measurement time
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