5,044 research outputs found
Above Barrier Dirac Multiple Scattering and Resonances
We extend an above barrier analysis made with the Schrodinger equation to the
Dirac equation. We demonstrate the perfect agreement between the barrier
results and back to back steps. This implies the existence of multiple (indeed
infinite) reflected and transmitted wave packets. These packets may be well
separated in space or partially overlap. In the latter case interference
effects can occur. For the extreme case of total overlap we encounter
resonances. The conditions under which resonance phenomena can be observed is
discussed and illustrated by numerical calculations.Comment: 12 pages, 1 figur
The flux pinning force and vortex phase diagram of single crystal FeTe0.60Se0.40
The flux pinning force density (Fp) of the single crystalline FeTe0.60Se0.40
superconductor has been calculated from the magnetization measurements. The
normalized Fp versus h (=H/Hirr) curves are scaled using the Dew-Hughes formula
to underline the pinning mechanism in the compound. The obtained values of
pinning parameters p and q indicate the vortex pinning by the mixing of the
surface and the point core pinning of the normal centers. The vortex phase
diagram has also been drawn for the first time for the FeTe0.60Se0.40, which
has very high values of critical current density Jc ~ 1.10(5) Amp/cm2 and the
upper critical field Hc2(0) = 65T, with a reasonably high transition
temperature Tc =14.5K.Comment: 12 pages, 4 figure
Testing a brief web-based intervention to increase recognition of tobacco constituents
Objective: We examined website formats to increase smokers\u27 recognition of harmful and potentially harmful constituents (HPHCs) in cigarettes.
Methods: Adult, daily smokers (N = 279) were randomized to view a brief, single-page study website showing HPHC names and uses. The intervention site was tailored + interactive, labeled by cigarette brand/subbrand showing color imagery and pop-up boxes; the generic + static website (control) was unbranded in greyscale. Eye tracking equipment measured attention (dwell time) to precise website features. Linear regression analyses compared attention to HPHC descriptions and the correct recognition of 15 HPHC chemicals. A randomly selected sub-sample (N = 30) of participants qualitatively rated website usability.
Results: Despite spending less dwell time on the HPHC text and entire website, adult smokers who viewed the generic + static website had greater improvement in HPHC recognition compared to the tailored + interactive website (4.6 vs 3.6; p = .02); this finding contrasts with current literature on tailoring and interactivity. Both websites were rated highly on ease-of-use and readability.
Conclusions: Basic formats and narrative HPHC Web-based content attracted less visual attention, yet increased recognition of these chemicals in cigarettes, compared to brand-tailored, interactive web-based content
Lagrangian Time Series Models for Ocean Surface Drifter Trajectories
This paper proposes stochastic models for the analysis of ocean surface
trajectories obtained from freely-drifting satellite-tracked instruments. The
proposed time series models are used to summarise large multivariate datasets
and infer important physical parameters of inertial oscillations and other
ocean processes. Nonstationary time series methods are employed to account for
the spatiotemporal variability of each trajectory. Because the datasets are
large, we construct computationally efficient methods through the use of
frequency-domain modelling and estimation, with the data expressed as
complex-valued time series. We detail how practical issues related to sampling
and model misspecification may be addressed using semi-parametric techniques
for time series, and we demonstrate the effectiveness of our stochastic models
through application to both real-world data and to numerical model output.Comment: 21 pages, 10 figure
Philosophical Foundations of Wisdom
Practical wisdom (hereafter simply ‘wisdom’), which is the understanding required to make reliably good decisions about how we ought to live, is something we all have reason to care about. The importance of wisdom gives rise to questions about its nature: what kind of state is wisdom, how can we develop it, and what is a wise person like? These questions about the nature of wisdom give rise to further questions about proper methods for studying wisdom. Is the study of wisdom the proper subject of philosophy or psychology? How, exactly, can we determine what wisdom is and how we can get it? In this chapter, we give an overview of some prominent philosophical answers to these questions. We begin by distinguishing practical wisdom from theoretical wisdom and wisdom as epistemic humility. Once we have a clearer sense of the target, we address questions of method and argue that producing a plausible and complete account of wisdom will require the tools of both philosophy and empirical psychology. We also discuss the implications this has for prominent wisdom research methods in empirical psychology. We then survey prominent philosophical accounts of the nature of wisdom and end with reflections on the prospects for further interdisciplinary research
On topological interpretation of quantum numbers
It is shown how one can define vector topological charges for topological
exitations of non-linear sigma-models on compact homogeneous spaces T_G and
G/T_G (where G is a simple compact Lie group and T_G is its maximal commutative
subgroup). Explicit solutions for some cases, their energies and interaction of
different topological charges are found. A possibility of the topological
interpretation of the quantum numbers of groups and particles is discussed.Comment: 20 pages, Latex 2e, modified versio
Genetic diversity and shedding profiles for Cryptosporidium parvum in adult cattle and their calves
Cryptosporidiosis is an important disease in neonatal calves, causing watery diarrhoea, loss of appetite, and production losses. Dehydration from diarrhoea often results in the calf requiring rehydration or veterinary treatment to prevent calf mortality. Transmission of Cryptosporidium to calves still has some major knowledge gaps, such as the initial source of oocysts ingested by calves and how these oocysts can persist between calving periods. Some studies have examined the role of adult cattle in the transmission of Cryptosporidium oocysts, although these have yielded inconclusive results. In this study, highly sensitive oocyst extraction from faeces and detection techniques, sensitive to 5 oocysts per gram using a 50 g sample, were used to genotype faecal samples from adult cattle and their calves to determine if adult cattle could be a source of Cryptosporidium infection for their calves. On a dairy farm, faecal samples from adult cattle were collected twice per week for 0–3 weeks before calving and from their calves three times per week until they reached 3 weeks of age followed by twice per week until they reached 6 weeks of age. On a beef farm, samples were collected from both adults and calves at a single time point. Faecal samples were examined to compare species and multilocus genotypes of Cryptosporidium parvum. Results show that C. parvum was the most prevalent species on both the dairy and beef farms. The calves within each herd appear to have one predominant single multilocus genotype, whereas adult cattle have multiple distinct genotypes. Adult cattle on the dairy farm, tested before calving, in the majority of cases had a multilocus genotype that is different from that detected in their calves. On the beef farm, where samples were taken at the same time, the majority of adult cattle matched the multilocus genotype of their calves. This study shows that adult cattle display a higher diversity of C. parvum genotypes on both farms compared to the calves. The data also represent a detailed longitudinal prevalence study of the shedding profiles and genotype of Cryptosporidium parasites detected in dairy calves from birth to 6 weeks of age
Detection of small coronary calcifications in patients with Agatston coronary artery calcium score of zero
Antimicrobial susceptibility monitoring of Mycoplasma hyopneumoniae isolated from seven European countries during 2015-2016
Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia, a chronic respiratory disease, causing significant economic losses. Results from the 2015-2016 MycoPath pan-European antimicrobial susceptibility monitoring survey of M. hyopneumoniae are presented. In total, 147 M. hyopneumoniae porcine isolates from Belgium, France, Germany, Great Britain, Hungary, Italy, and Spain were tested. One isolate per farm was retained from pigs that had not been recently treated with antimicrobial agents. The minimal inhibitory concentration (MIC) of 13 antimicrobial agents was determined in a central laboratory using a broth microdilution method, with Friis Medium, incubated at 35 +/- 1 degrees C for 5-12 days. M. hyopneumoniae NCTC 10110 was used as Quality Control. MIC50/MIC90 (mg/L) values were: enrofloxacin 0.06/1; marbofloxacin 0.06/2; spiramycin 0.06/0.25; tulathromycin <= 0.001/0.004; gamithromycin 0.06/0.5; tylosin 0.016/0.06; tilmicosin 0.06/0.5; florfenicol 0.5/1; doxycycline 0.25/1; oxytetracycline 0.25/2; lincomycin 0.06/0.25; tiamulin 0.016/0.06 and valnemulin <= 0.001/0.004. Compared with the data from 2010 to 2012 MycoPath study (50 isolates), MIC50/90 results were similar and the majority were within +/- two dilution steps, except for the MIC50 of oxytetracycline which is more than two dilution steps higher in the present study. Between-country comparisons show some differences in the MIC values for the fluoroquinolones, tulathromycin and tylosin, but the limited sample size per country precludes performing meaningful country comparisons for several countries. Standardized laboratory methods and interpretive criteria for MIC testing of veterinary mycoplasmas are clearly needed; there are currently no clinical breakpoints available to facilitate data interpretation and correlation of MICs with in vivo efficacy
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