1,824 research outputs found
Experience, expertise and expert-performance research in public accounting
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The role of tax practitioners in tax reporting : a signalling game
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The Seasonal Cycle and Interannual Variability in Stratospheric Temperatures and Links to the BrewerâDobson Circulation: An Analysis of MSU and SSU Data
Previous studies have shown that lower-stratosphere temperatures display a near-perfect cancellation between tropical and extratropical latitudes on both annual and interannual time scales. The out-of-phase relationship between tropical and high-latitude lower-stratospheric temperatures is a consequence of variability in the strength of the BrewerâDobson circulation (BDC). In this study, the signal of the BDC in stratospheric temperature variability is examined throughout the depth of the stratosphere using data from the Stratospheric Sounding Unit (SSU). While the BDC has a seemingly modest signal in the annual cycle in zonal-mean temperatures in the mid- and upper stratosphere, it has a pronounced signal in the month-to-month and interannual variability. Tropical and extratropical temperatures are significantly negatively correlated in all SSU channels on interannual time scales, suggesting that variations in wave driving are a major factor controlling global-scale temperature variability not only in the lower stratosphere (as shown in previous studies), but also in the mid- and upper stratosphere. The out-of-phase relationship between tropical and high latitudes peaks at all levels during the cold-season months: DecemberâMarch in the Northern Hemisphere and JulyâOctober in the Southern Hemisphere. In the upper stratosphere, the out-of-phase relationship with high-latitude temperatures extends beyond the tropics and well into the extratropics of the opposite hemisphere. The seasonal cycle in stratospheric temperatures follows the annual march of insolation at all levels and latitudes except in the mid- to upper tropical stratosphere, where it is dominated by the semiannual oscillation. M
Speciation of Arsenic in Ambient Aerosols Collected in Los Angeles
First-time measurements of the potentially toxic inorganic species of arsenic (arsenite arid arsenate) have been obtained in fine (2.5 ”m AD) atmospheric particles in the Los Angeles area. A recently developed method that includes procedures for sample collection, preparation, and analysis was used in this study. Size-fractlonated aerosol samples were collected with a high-volume dichotomous virtual impactor that employed polytetrafluoroethylene filters. Results were obtained for the recovery of arsenic standards added to unexposed and collected filters. Data from this study, indicated that the recently developed speciation method can be used to determine concentrations of As(lll) and As(V) In atmospheric particulate matter samples.
Size-fractionated aerosol samples were collected in the city of Industry during January and February 1987. In most samples, As(lll) and As( V) were above the detection limit (approximately 1 ng m-3 of either species) in both aerosol size fractions. A greater portion (about 75 percent) of the two species were observed in the fine particles. The As(lll)/As(V) ratio for both particle sizes was close to 1 (I.e., an equal mixture of both species). Comparison of total suspended particulate arsenic measured by the speciation method to that measured by a routine California Air Resources Board-approved procedure showed good agreement (r = 0.94), indicating both methods were approximately equivalent for the collection and analysis of aerosol arsenic
Scientific Rationale and Requirements for a Global Seismic Network on Mars
Following a brief overview of the mission concepts for a Mars Global Network Mission as of the time of the workshop, we present the principal scientific objectives to be achieved by a Mars seismic network. We review the lessons for extraterrestrial seismology gained from experience to date on the Moon and on Mars. An important unknown on Mars is the expected rate of seismicity, but theoretical expectations and extrapolation from lunar experience both support the view that seismicity rates, wave propagation characteristics, and signal-to-noise ratios are favorable to the collection of a scientifically rich dataset during the multiyear operation of a global seismic experiment. We discuss how particular types of seismic waves will provide the most useful information to address each of the scientific objectives, and this discussion provides the basis for a strategy for station siting. Finally, we define the necessary technical requirements for the seismic stations
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DELAYED MITOGENIC STIMULATION DECREASES DNA DAMAGE ASSESSED BY MICRONUCLEUS ASSAY IN HUMAN PERIPHERAL BLOOD LYMPHOCYTES AFTER 60CO IRRADIATION
While contradictory reports are available on the yield of dicentric chromosomes (DC) in blood samples stored at different temperature and stimulated to enter into cell cycle, various times gap followed by exposure, limited information is available on the micronucleus (MN) assay. As scoring the micronuclei frequency from the blood lymphocytes of exposed individuals is an alternative to the gold standard DC assay for triage applications, we examined radiation induced MN yield in delayed mitogenic stimulation after irradiation of in vitro. Peripheral blood lymphocytes (PBL) were exposed to low LET (60Co) radiation dose (0.1 to 5Gy) and incubated at 37°C for 2, 6 and 24 hours. The MN frequency obtained in blood samples stimulated 2 hours post-irradiation showed a dose dependent increase and used to construct the dose-response curve. Further, the results also showed that blood samples stimulated twenty four hours of post-irradiation, a significant reduction (p\u3c0.05) in MN frequencies were obtained when compared to that of blood samples stimulated two hours and six hours after post-irradiation (0.5, 1, 3 and 5Gy). The observed result suggests that the prolonged PBL storage without mitogenic stimulation could lead to interphase cell death and a delayed blood sampling could results in underestimation of dose in biological dosimetry
The modules of mental health programs implemented in schools in low- and middle-income countries: findings from a systematic literature review
Background: Secondary schools in low- and middle-income countries (LMICs) provide health promotion, preventive, and early intervention services. Nevertheless, literature indicates that the modules of these services are either adapted or modified from existing mental health programs in developed countries. The literature also
highlights the provision of non-comprehensive services (mental health promotion, prevention, and early intervention), in LMICs. These findings inform the need for undertaking this systematic literature review. The aim of this review was thus to identify the modules of school-based mental health programs (SBMHP) that have been implemented in LMICs to guide the development of a culturally sensitive comprehensive mental health program for adolescents in a LMIC country.
Methods: The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was used to guide this review. The following databases were searched in September 2018, to identify the relevant literature: PubMed, CINAHL, Scopus, Web of Science, PsycINFO, and ERIC. The search was conducted by the first author and reviewed by the authors.
Results: Following the screening process, a total of 11 papers were identified and reviewed for quality. The systematic review highlighted that the mental health programs provided in schools included: an introduction module, a communication and relationship module, a psychoeducation module, a cognitive skills module, a
behavioral skills module, establishing social networks for recovery and help seeking behavioral activities and a summary/conclusion module.
Conclusion: This review sheds light on the characteristics of the programs in LMICs. Two programs were found to be universal in nature. Five programs were directed at key risk factors or at-risk groups, and four were early intervention programs. The review also revealed that only one program out of the 11 programs included modules for parents. The synthesis indicated that all the identified programs were adapted or modified from existing programs. The dearth of comprehensive programs in LMICs was also revealed. Lastly, the review revealed seven modules that can be useful for developing a SBMHP
A Face Versus Non-Face Context Influences Amygdala Responses to Masked Fearful Eye Whites
The structure of the mask stimulus is crucial in backward masking studies and we recently demonstrated such an effect when masking faces. Specifically, we showed that activity of the amygdala is increased to fearful facial expressions masked with neutral faces and decreased to fearful expressions masked with a pattern maskâbut critically both masked conditions discriminated fearful expressions from happy expressions. Given this finding, we sought to test whether masked fearful eye whites would produce a similar profile of amygdala response in a face vs non-face context. During functional magnetic resonance imaging scanning sessions, 30 participants viewed fearful or happy eye whites masked with either neutral faces or pattern images. Results indicated amygdala activity was increased to fearful vs happy eye whites in the face mask condition, but decreased to fearful vs happy eye whites in the pattern mask conditionâeffectively replicating and expanding our previous report. Our data support the idea that the amygdala is responsive to fearful eye whites, but that the nature of this activity observed in a backward masking design depends on the mask stimulus
A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course
Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, inflammatory disease of the central nervous system marked by relapses often associated with poor recovery and long-term disability. Magnetic resonance imaging (MRI) is recognized as an important tool for timely diagnosis of NMOSD as, in combination with serologic testing, it aids in distinguishing NMOSD from possible mimics. Although the role of MRI for disease monitoring after diagnosis is not as well established, MRI may provide important prognostic information and help differentiate between relapses and pseudorelapses. Increasing evidence of subclinical disease activity and the emergence of newly approved, highly effective immunotherapies for NMOSD adjure us to re-evaluate MRI as a tool to guide optimal treatment selection and escalation throughout the disease course. In this article we review the role of MRI in NMOSD diagnosis, prognostication, disease monitoring, and treatment selection
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