614 research outputs found
Analytic Extension and Conformal Mapping in the Dual and the Double Planes
Many theorems in the complex plane have analogues in the dual (x+jy, j2=0) and the double (x+ky, k2=1) planes. In this paper, we prove that Schwarz reflection principle holds in the dual and the double planes. We also show that in these two planes the domain of an analytic function can usually be extended analytically to a larger region. In addition, we find that a certain class of regions can be mapped conformally to the upper half plane, which is analogous to the Riemann mapping theorem
Positive and Negative Thinking in Tinnitus: Factor Structure of the Tinnitus Cognitions Questionnaire
Objectives: Researchers and clinicians consider thinking to be important in the development and maintenance of tinnitus distress, and altering thoughts or thinking style is an object of many forms of psychological therapy for tinnitus. Those working with people with tinnitus require a reliable, psychometrically robust means of measuring both positive and negative thinking related to it. The Tinnitus Cognitions Questionnaire (TCQ) was designed as such a measure and its authors showed it to be reliable, with good psychometric properties. However, no research teams have yet carried out independent validation. This study aimed to use the TCQ to investigate thinking amongst members of the general population with both bothersome and nonbothersome tinnitus and also to verify its factor structure.Design: Three hundred forty-two members of the public with tinnitus completed the TCQ online or on paper. They also rated their tinnitus on a scale as ânot a problem,â âa small problem,â âa moderate problem,â âa big problem,â or a âvery big problem.â The authors tested the original factor structure of the TCQ using confirmatory factor analysis and then calculated the mean scores for each item, comparing mean total scores across âproblem categoriesâ for the full questionnaire and for the positive and negative subscales.Results: The original two-factor structure of the TCQ was a good fit to the data when the correlation between positive and negative factors was fixed at zero (root mean square error of approximation = 0.064, 90% confidence interval = 0.058 to 0.070). Items pertaining to wishing the tinnitus would go away and despairing that it would ever get better had the highest mean scores. The mean total score for the âno problemâ group (M = 31.17, SD = 16.03) was not significantly different from the mean total score for the âsmall problemâ group (M = 34.00, SD = 12.44, p = 0.99). Differences between mean scores for all other groups were statistically significant. For the negative subscale, differences were statistically significant between all problem categories. For the positive subscale, the differences between mean scores were only statistically significant for the âno problemâ group (M = 28.40, SD = 17.11) compared with the âmoderate problemâ group (M = 18.55, SD = 8.64, p = 0.02) and for the âmoderate problemâ group compared with the âvery big problemâ group (M = 26.79, SD = 11.66, p = 0.002). Positive and negative factors were uncorrelated (Ď = â0.03.)Conclusions: The TCQ is a valid measure of positive and negative thinking in tinnitus, and the authors recommend its use in research and therapeutic settings. Negative thinking appears to be associated with more problematic tinnitus, but positive thinking is not associated with unproblematic tinnitus, suggesting that reducing negative thinking may be more important than teaching positive thinking in therapy
Large impacts of small methane fluxes on carbon isotope values of soil respiration
Carbon dioxide isotope (δ13C of CO2) analysis is increasingly used to address a broad range of questions involving soil C dynamics and respiration sources. However, attaining δ13C mass balance is critical for robust interpretation. Many ecosystems exhibit methane (CH4) fluxes that are small in the context of total C budgets, yet may significantly impact δ13C values of CO2 due to large kinetic fractionations during CH4 production. Thus, the δ13C values of CO2 do not directly reflect respiration C sources when co-occurring with CH4, but few studies of terrestrial soils have considered this phenomenon. To assess how CH4 altered the interpretation of δ13C values of CO2, we incubated a Mollisol and Oxisol amended with C4-derived plant litter for 90 days under two headspace treatments: a fluctuating anaerobic/aerobic treatment (four days of anaerobic conditions alternating with four days of aerobic conditions), and a static aerobic treatment (control). We measured δ13C values of CO2 and CH4 with a tunable diode laser absorption spectrometer, using a novel in-line combustion method for CH4. Cumulative δ13C of CO2 differed significantly between treatments in both soils. The δ13C values of CO2 were affected by relatively small CH4 fluxes in the fluctuating anaerobic/aerobic treatment. Effects of CH4 on δ13C values of CO2 were greater in the Oxisol due to its higher percent contribution of CH4 to total C mineralization(18%) than in the Mollisol (3%) during periods of elevated CH4 production. When CH4accounted for just 2% of total C mineralization, the δ13C values of CO2 differed from total C mineralization by 0.3â1â°, and by 1.4â4.8â° when CH4 was 10% of C mineralization. These differences are highly significant when interpreting natural abundance δ13C data. Small CH4fluxes may strongly alter the δ13C values of CO2 relative to total mineralized C. A broad range of mineral and peatland soils can experience temporary oxygen deficits. In these dynamic redox environments, the δ13C values of CO2 should be interpreted with caution and ideally combined with δ13C of CH4 when partitioning sources and mechanisms of soil respiration
Quantitative determination of reducing sugars, oligosaccharides, and glycoproteins with [3H]borohydride
A very simple and direct radioactive isotope method has been described for the quantitative determination of reducing sugars. The method can be adapted to give any degree of sensitivity desired. The procedure is of general applicability to the determination of a large class of sugars. The stoichiometry of the reaction makes it a comprehensive procedure which greatly facilitates the analysis of sugars, oligosaccharides, and glycoproteins after acid and enzymic hydrolysis. Examples of the versatility of the method are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33817/1/0000074.pd
Ecologic and Geographic Distribution of Filovirus Disease
We used ecologic niche modeling of outbreaks and sporadic cases of filovirus-associated hemorrhagic fever (HF) to provide a large-scale perspective on the geographic and ecologic distributions of Ebola and Marburg viruses. We predicted that filovirus would occur across the Afrotropics: Ebola HF in the humid rain forests of central and western Africa, and Marburg HF in the drier and more open areas of central and eastern Africa. Most of the predicted geographic extent of Ebola HF has been observed; Marburg HF has the potential to occur farther south and east. Ecologic conditions appropriate for Ebola HF are also present in Southeast Asia and the Philippines, where Ebola Reston is hypothesized to be distributed. This first large-scale ecologic analysis provides a framework for a more informed search for taxa that could constitute the natural reservoir for this virus family
Model-Independent Short-Baseline Oscillations from Reactor Spectral Ratios
We consider the ratio of the spectra measured in the DANSS neutrino
experiment at 12.7 and 10.7~m from a nuclear reactor. These data give a new
model-independent indication in favor of short-baseline
oscillations which reinforce the model-independent indication found in the late
2016 in the NEOS experiment. The combined analysis of the NEOS and DANSS
spectral ratios in the framework of 3+1 active-sterile neutrino mixing favor
short-baseline oscillations with a statistical significance of
. The two mixing parameters and
are constrained at in a
narrow- island at , with ().
We discuss the implications of the model-independent NEOS+DANSS analysis for
the reactor and Gallium anomalies. The NEOS+DANSS model-independent
determination of short-baseline oscillations allows us to analyze
the reactor rates without assumptions on the values of the main reactor
antineutrino fluxes and the data of the Gallium source experiments with free
detector efficiencies. The corrections to the reactor neutrino fluxes and the
Gallium detector efficiencies are obtained from the fit of the data. In
particular, we confirm the indication in favor of the need for a recalculation
of the reactor antineutrino flux found in previous studies
assuming the absence of neutrino oscillations.Comment: 10 pages; analysis improved by taking into account the uncertainties
of the reactor fission fraction
Topographic asymmetry of the South Atlantic from global models of mantle flow and lithospheric stretching
Can We Predict Burnout among Student Nurses? An Exploration of the ICWR-1 Model of Individual Psychological Resilience
The nature of nursing work is demanding and can be stressful. Previous studies have shown a high rate of burnout among employed nurses. Recently, efforts have been made to understand the role of resilience in determining the psychological adjustment of employed nurses. A theoretical model of resilience was proposed recently that includes several constructs identified in the literature related to resilience and to psychological functioning. As nursing students are the future of the nursing workforce it is important to advance our understanding of the determinants of resilience in this population. Student nurses who had completed their final practicum were invited to participate in an online survey measuring the key constructs of the ICWR-1 model. 422 students from across Australia and Canada completed the survey between July 2014 and July 2015. As well as several key demographics, trait negative affect, mindfulness, self-efficacy, coping, resilience, and burnout were measured. We used structural equation modeling and found support for the major pathways of the model; namely that resilience had a significant influence on the relationship between mindfulness, self-efficacy and coping, and psychological adjustment (burnout scores). Furthermore, as predicted, Neuroticism moderated the relationship between coping and burnout. Results are discussed in terms of potential approaches to supporting nursing students who may be at risk of burnout
Elevated CO2 degassing rates prevented the return of Snowball Earth during the Phanerozoic
The Cryogenian period (~720â635âMa) is marked by extensive Snowball Earth glaciations. These have previously been linked to COâ draw-down, but the severe cold climates of the Cryogenian have never been replicated during the Phanerozoic despite similar, and sometimes more dramatic changes to carbon sinks. Here we quantify the total COâ input rate, both by measuring the global length of subduction zones in plate tectonic reconstructions, and by sea-level inversion. Our results indicate that degassing rates were anomalously low during the Late Neoproterozoic, roughly doubled by the Early Phanerozoic, and remained comparatively high until the Cenozoic. Our carbon cycle modelling identifies the Cryogenian as a unique period during which low surface temperature was more easily achieved, and shows that the shift towards greater COâ input rates after the Cryogenian helped prevent severe glaciation during the Phanerozoic. Such a shift appears essential for the development of complex animal life
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