228 research outputs found
A CASSCF Study of Various Rotamers of the Hexatriene Radical Cation
Results are presented from ab initio calculations on the ground and two low-lying excited states of the hexatriene radical cation in a variety of stable conformations of the electronic ground state of the molecule. We have performed Hartree-Fock geometry optimizations using the STO-3G and 6-31g basis sets and have performed vibrational analyses for all stable conformers in the 6-31G basis. In addition, we have performed geometry optimizations in both basis sets using CASSCF wave functions where the five π electrons are correlated. No new geometrical information is obtained at this level of treatment. Excitation energies to the two lowest-lying doublet π excited states for the six stable ground-state geometries were also calculated using CASSCF wave functions. These excitation energies are compared with previous experimental assignments of observed transitions in photolytically generated hexatriene radical cations
Resonance Raman Investigation of the Radical Cation of 1,3,5-Hexatriene
The resonance Raman spectrum of the 1,3,5-hexatriene radical cation generated by v-irradiation in a Freon glass is reported. The spectrum is excited at 395 nm in resonance with the second absorption band. Identical spectra are obtained from ionized (E)- and (Z)-1,3,5-hexatriene. The presence of more than one rotamer has to be assumed to account for all the observed resonance Raman bands. The bands are assigned to a mixture of the two rotamers, calculated at lowest energy, the ttt an tct rotamers, on the basis of ab initio ROHF/6-31G calculated harmonic frequencies. The spectrum indicates that the ttt and tct rotamers are formed in a ratio in the range 0.4./0.6-0.6/0.4. Two possible mechanisms are proposed to explain the presence of these two rotamers
Use of the i2b2 research query tool to conduct a matched case–control clinical research study: advantages, disadvantages and methodological considerations
Background: A major aim of the i2b2 (informatics for integrating biology and the bedside) clinical data informatics framework aims to create an efficient structure within which patients can be identified for clinical and translational research projects. Our objective was to describe the respective roles of the i2b2 research query tool and the electronic medical record (EMR) in conducting a case-controlled clinical study at our institution. Methods: We analyzed the process of using i2b2 and the EMR together to generate a complete research database for a case–control study that sought to examine risk factors for kidney stones among gastrostomy tube (G-tube) fed children. Results: Our final case cohort consisted of 41/177 (23%) of potential cases initially identified by i2b2, who were matched with 80/486 (17%) of potential controls. Cases were 10 times more likely to be excluded for inaccurate coding regarding stones vs. inaccurate coding regarding G-tubes. A majority (67%) of cases were excluded due to not meeting clinical inclusion criteria, whereas a majority of control exclusions (72%) occurred due to inadequate clinical data necessary for study completion. Full dataset assembly required complementary information from i2b2 and the EMR. Conclusions: i2b2 was critical as a query analysis tool for patient identification in our case–control study. Patient identification via procedural coding appeared more accurate compared with diagnosis coding. Completion of our investigation required iterative interplay of i2b2 and the EMR to assemble the study cohort
Genome-wide analysis of lectin receptor-like kinases in Populus
Transcript level of C-type PtLecRLK gene in 24 different datasets from the Populus Gene Atlas Study. RNA-seq data were collected from the Populus Gene Atlas Study in Phytozome v11.0 ( http://phytozome.jgi.doe.gov/pz/portal.html ). The transcript level was expressed as FPKM. The sheet labeled as “whole_set” contains the original FPKM values from Gene Atlas. The data of four different tissues under standard condition are sorted in the data sheet labeled as “standard”. (XLSX 10 kb
A study of the effect of the oily portion of soil on the soiling and soil retention properties of a filament nylon tricot fabric
Thesis (M.A.)--Michigan State University of Agriculture and Applied Science. Dept. of Textiles, Clothing and Related Arts, 1962Includes bibliographical references (leaves 54-58
On the making and taking of professionalism in the further education workplace
This paper examines the changing nature of professional practice in English further education. At a time when neo-liberal reform has significantly impacted on this under-researched and over-market-tested sector, little is known about who its practitioners are and how they construct meaning in their work. Sociological interest in the field has tended to focus on further education practitioners as either the subjects of market and managerial reform or as creative agents operating within the contradictions of audit and inspection cultures. In challenging such dualism, which is reflective of wider sociological thinking, the paper examines the ways in which agency and structure combine to produce a more transformative conception of the further education professional. The approach contrasts with a prevailing policy discourse that seeks to re-professionalise and modernise further education practice without interrogating either the terms of its professionalism or the neo-liberal practices in which it resides
Youth throwing athletes do not show bilateral differences in medial elbow width or flexor tendon thickness
Background: Medial elbow laxity develops in throwing athletes due to valgus forces. Medial elbow instability in professional, collegiate, and high school athletes is well documented; however, the medial elbow of young throwing athletes has received less attention. This study investigated the medial elbow and common flexor tendon during applied elbow valgus stress of youth baseball players.
Methods: The study included 15 participants. The medial elbow width and thickness of the common flexor tendon were measured on ultrasound images.
Results: No significant side differences in medial elbow width or common flexor tendon were found at rest or under applied valgus stress. At rest, the medial elbow joint width was 3.34±0.94 mm on the dominant side and 3.42±0.86 mm on the non-dominant side. The dominant side increased to 3.83±1.02 mm with applied valgus stress, and the non-dominant side increased to 3.96±1.04 mm. The mean flexor tendon thickness was 3.89±0.63 mm on the dominant side and 4.02±0.70 mm on the non-dominant side.
Conclusions: These findings differ from similar studies in older throwing athletes, likely because of the lack of accumulated stress on the medial elbow of youth throwing athletes. Maintaining elbow stability in young throwing athletes is a vital step to preventing injury later in their careers
Indicated Truancy Interventions: Effects on School Attendance Among Chronic Truant Students.
BACKGROUNDTruancy is a significant problem in the U.S. and in other countries around the world. Truancy has been linked to serious immediate and far-reaching consequences for youth, families, and schools and communities, leading researchers, practitioners, and policy makers to try to understand and to address the problem. Although numerous and significant steps have been taken at the local, state, and national levels to reduce truancy, the rates of truancy have at best remained stable or at worst been on the rise, depending on the indicator utilized to assess truancy rates. The costs and impact of chronic truancy are significant, with both short- and long-term implications for the truant youth as well as for the family, school, and community. Although several narrative reviews and one meta-analysis of attendance and truancy interventions have attempted to summarize the extant research, there are a number of limitations to these reviews. It is imperative that we systematically synthesize and examine the evidence base to provide a comprehensive picture of interventions that are being utilized to intervene with chronic truants, to identify interventions that are effective and ineffective, and to identify gaps and areas in which more research needs to be conducted to better inform practice and policy.OBJECTIVESThe main objective of this systematic review was to examine the effects of interventions on school attendance to inform policy, practice, and research. The questions guiding this study were: 1) Do truancy programs with a goal of increasing student attendance for truant youth affect school attendance behaviors of elementary and secondary students with chronic attendance problems?2) Are there differences in the effects of school-based, clinic/community-based, and court-based programs?3) Are some modalities (i.e., family, group, multimodal) more effective than others in increasing student attendance? SEARCH STRATEGYA systematic and comprehensive search process was employed to locate all possible studies between 1990 and 2009, with every effort made to include both published and unpublished studies to minimize publication bias. A wide range of electronic bibliographic databases and research registers was searched, websites of relevant research centers and groups were mined for possible reports, over 200 e-mails and letters were sent to programs listed in large databases of truancy programs compiled by the National Center for School Engagement and the National Dropout Prevention Center, and contact with researchers in the field of truancy and absenteeism was attempted. In addition, we examined reference lists of all previous reviews as well as citations in research reports for potential studies.SELECTION CRITERIAStudies eligible for this review were required to meet several eligibility criteria. Studies must have utilized a randomized, quasi-experimental, or single-group pre-posttest design with the aim of evaluating the effectiveness of interventions with a stated primary goal of increasing student attendance (or decreasing absenteeism) among chronic truant students. Studies must have measured an attendance outcome and reported sufficient data to calculate an effect size. Finally, studies must have been published between 1990 and 2009 in the United States, United Kingdom, Australia, or Canada. DATA COLLECTION AND ANALYSISA total of 28 studies, reported in 26 reports, met final eligibility criteria and were included in this review and meta-analysis. Of the studies that were included, 5 utilized a randomized design (RCT), 11 utilized a quasi-experimental design (QED), and 12 utilized a single group pre-posttest design (SGPP). All eligible studies were coded using a structured coding instrument, with 20% of studies coded by a second coder. Descriptive analysis was conducted to examine and describe data related to the characteristics of the included studies. Analysis of the mean effect size, the heterogeneity of effect sizes, and the relationship between effect size and methodological and substantive characteristics of the interventions was also conducted separately for the RCT/QED studies and the SGPP studies. The effect sizes were calculated using the standardized mean difference effect size statistic, correcting for small sample size using Hedges’ g (Hedges, 1992). Assuming a mixed effects model, the analog to the ANOVA and bivariate meta-regression frameworks were used to examine potential moderating variables related to study, participant, and intervention characteristics. RESULTSThe meta-analytic findings demonstrated a significant overall positive and moderate mean effect of interventions on attendance outcomes. The mean effect size for interventions examined in the included RCT studies was .57 and the mean effect size for the QED studies was .43. No significant differences were observed between the RCT and QED studies in the magnitude of the treatment effect (Qb= .28, p \u3e.05). The mean effect size of interventions examined using an SGPP design was .95. A moderate effect on attendance outcomes is encouraging; however, the overall mean effect size is masked by a large amount of heterogeneity, indicating significant variance in effect sizes between studies. Moderator analyses found no significant differences in mean effects between studies on any moderating variable tested. No differences were found between school-, court-, or community-based programs or between different modalities of programs. The duration of the intervention also did not demonstrate any association with effect size. Collaborative programs and multimodal interventions produced statistically similar effects on attendance as non-collaborative and single-modality programs, which runs counter to the prevailing beliefs and recommendations for best practices in truancy reduction found in the literature.Other significant findings from this study relate to methodological shortcomings, the absence of important variables as well as gaps in the evidence base. These findings include the lack of inclusion of minority students and a lack of reporting and statistical analysis of demographic variables, particularly race/ethnicity and socioeconomic status (SES). Given that race and SES have been linked to absenteeism, the absence of this data was surprising. The majority of studies also lacked adequate descriptions of the interventions, making replication of the intervention difficult, and failed to measure and report long-term outcomes. AUTHORS’ CONCLUSIONSOverall, the findings from this study suggest that chronic truant students benefit from interventions targeting attendance behaviors; thus it is important and worthwhile to intervene with chronic truant youth. Given the minimal differences in effects across program types and modalities, no one program type or modality stands out as being more effective than any other. Although no statistically significant differences in effects were found between types and modalities of interventions included in this review, there was a lack of available evidence to support the general belief (and popular “best-practice” recommendations) that collaborative and multimodal interventions are more effective than programs that are not collaborative and single modal interventions. Due to the small sample size and large heterogeneity between studies and within groups of studies, caution must be used when interpreting and applying the findings from this meta-analysis. Overall, the studies included in the review improved attendance by an average of 4.69 days, almost a full school week. However, although the interventions included in this study were, overall, found to be effective, the mean rates of absenteeism at posttest in most studies remained above acceptable levels. This finding indicates the need for additional work and research. Developing more effective interventions and policies as well as studying outcomes of interventions, particularly with vulnerable and at-risk populations, is crucial to combating absenteeism. The gaps and deficiencies identified in this study also affirm the need for increasing and strengthening the evidence base on which current policies and practices rest. Although additional outcome research is necessary, more of the same is not sufficient. Significant improvements in the quality of truancy intervention research are required and identified gaps need to be addressed. Recommendations to improve the quality and fill gaps in truancy intervention research are discussed here. In addition, given the significant and pervasive deficiencies in the extant research, a critical analysis of the practices, assumptions, and sociopolitical contexts underlying truancy intervention research seems warranted
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