1,749 research outputs found

    Simple Calculation of Instanton Corrections in Massive N=2 SU(3) SYM

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    We give an explicit derivation of the Picard-Fuchs equations for N=2 supersymmetric SU(3) Yang-Mills theory with Nf<6N_f<6 massive hypermultiplets in the fundamental representation. We determine the instanton corrections to the prepotential in the weak coupling region using the relation between \tr and the prepotential. This method can be generalized to other gauge groups.Comment: 16 pages, Late

    Characterization of vertical electric fields and associated voltages induced on a overhead power line from close artificially initiated lightning

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    Measurements were characterized of simultaneous vertical electric fields and voltages induced at both ends of a 448 m overhead power line by artificially initiated lightning return strokes. The lightning discharges struck ground about 20 m from one end of the line. The measured line voltages could be grouped into two categories: those in which multiple, similarly shaped, evenly spaced pulses were observed, which are called oscillatory; and those dominated by a principal pulse with subsidiary oscillations of much smaller amplitude, which are called impulsive. Voltage amplitudes range from tens of kilovolts for oscillatory voltages to hundreds of kilovolts for impulsive voltages

    PXRF analysis of a yellow ochre quarry and rock art motifs in the Central Pilbara

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    The significance of ochre in Indigenous Australia is well documented. Several large, well-known quarries containing ochre that is highly sought after have been described in the archaeological literature, however less attention has been paid to smaller, regionally and locally significant quarries. In this paper a small yellow ochre quarry (VSTA_20140611_1) from the Central Pilbara, where evidence of paint preparation is preserved in the form of residues in two in situ grinding hollows, is described in order to address this oversight. Portable XRF (pXRF) analysis of the pigment in the quarry itself and the paint in the hollows was undertaken to understand the chemistry of the pigmentaceous minerals, to explore the taphonomy of the ochre seam, and to gauge variation within the source. Chemistry indicates that the VSTA_20140611_1 quarry is composed of an iron mineral (likely a hydroxide such as goethite), with Fe abundances consistently between 10.7 and 30%. Typical of the regional geology, the yellow pigment is consistently siliceous, with an Si abundance of between 5.8 and 20.4%. As there are no painted motifs in the rockshelter containing the VSTA_20140611_1 quarry, nor on the suitable BIF surfaces nearby, it is considered highly likely that the surviving paint produced on-site was used for either body decoration or the adornment of artefacts, rather than for rock art production. Nevertheless, the similarity in chemical composition between the VSTA_20140611_1 pigments and that of motifs painted in sites a few kilometres away suggests that, in addition to immediate processing and use at the site, ochre from this quarry may have been transported to rockshelters in the vicinity and used for rock art production

    Irreducible decomposition for tensor prodect representations of Jordanian quantum algebras

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    Tensor products of irreducible representations of the Jordanian quantum algebras U_h(sl(2)) and U_h(su(1,1)) are considered. For both the highest weight finite dimensional representations of U_h(sl(2)) and lowest weight infinite dimensional ones of U_h(su(1,1)), it is shown that tensor product representations are reducible and that the decomposition rules to irreducible representations are exactly the same as those of corresponding Lie algebras.Comment: LaTeX, 14pages, no figur

    Summary of CPWF research in the Nile river basin

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    Three major river basins flow out of Ethiopia into Sudan, constituting the Eastern Nile basin (the White Nile flows from the south). These are the Tekeze-Atbara flowing out of northern Ethiopia, the Baro-Akoba- Sobat flowing from southern Ethiopia, and the Blue Nile (Abay) sandwiched between the other two. The Blue Nile Basin, called the Abay in Ethiopia, is the largest branch of the Nile draining the Ethiopian highlands. It covers an estimated area of 311,437 square kilometers and is shared by Ethiopia and Sudan. It joins the White Nile in Khartoum, Sudan. The Ethiopian highlands portion of the Blue Nile river basin was the focus of the Nile Basin Development Challenge under the Challenge Program on Water and Food

    Identification of Movement Strategies during the Sit-to-Walk Movement in Patients with Knee Osteoarthritis

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    Patients with osteoarthritis (OA) of the knee commonly alter their movement to compensate for deficiencies. This study presents a new numerical procedure for classifying sit-to-walk (STW) movement strategies. Ten control and twelve OA participants performed the STW task in a motion capture laboratory. A full body biomechanical model was used. Participants were instructed to sit in a comfortable self-selected position on a stool height adjusted to 100% of their knee height and then stand and pick up an object from a table in front of them. Three matrices were constructed defining the progression of the torso, feet and hands in the sagittal plane along with a fourth expressing the location of the hands relative to the knees. Hierarchical clustering (HC) was used to identify different strategies. Trials were also classified as to whether the left (L) and right (R) extremities used a matching strategy (bilateral) or not (asymmetrical). Fisher’s exact test was used to compare this between groups. Clustering of the torso matrix dichotomised the trials in two major clusters; subjects leaning forward (LF) or not. The feet and hands matrices revealed sliding the foot backward (FB) and moving an arm forward (AF) strategies respectively. Trials not belonging in the AF cluster were submitted to the last HC of the fourth matrix exposing three additional strategies, the arm pushing through chair (PC), arm pushing through knee (PK) and arm not used (NA). The control participants used the LF+FBR+PK combination most frequently whereas the OA participants used the AFR+PCL. OA patients used significantly more asymmetrical arm strategies, p=0.034. The results demonstrated that control and OA participants favour different STW strategies. The OA patients asymmetrical arm behaviour possibly indicates compensating for weakness of the affected leg. These strategy definitions may be useful to assess post-operative outcomes and rehabilitation progress

    When a patient\u27s ethnicity is declared, medical students\u27 decision-making processes are affected

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    Background: Disparity in health status and healthcare outcomes is widespread and well known. This holds true for Indigenous peoples in many settings including Australia and Hawaii. While multi-factorial, there is increasing evidence of health practitioner contribution to this disparity. This research explored senior medical students’ clinical decision-making processes. Methods: A qualitative study was conducted in 2014 with 30 final year medical students from The University of Melbourne, Australia, and The John Burns Medical School, Hawaii, USA. Each student responded to questions about a paper-based case, first in writing and elaborated further in an interview. Half the students were given a case of a patient whose ethnicity was not declared; the other half considered the patient who was Native Hawaiian or Australian Aboriginal. A systematic thematic analysis of the interview transcripts was conducted. Results: The study detected subtle biases in students’ ways of talking about the Indigenous person and their anticipation of interacting with her as a patient. Four main themes emerged from the interview transcripts: the patient as a person; constructions of the person as patient; patient–student/doctor interactions; and the value of various education settings. There was a strong commitment to the patient’s agenda and to the element of trust in the doctor–patient interaction. Conclusion: These findings will help to advance medical curricula so that institutions graduate physicians who are increasingly able to contribute to equitable outcomes for all patients in their care. The study also draws attention to subtle biases based on ethnicity that may be currently at play in physicians’ practices

    Improving the yield and lifetime of microfabricated sensors for harsh environments

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    This paper details improvements in the design and fabrication of electrodes intended to function in the high temperature, corrosive environment of a molten salt. Previously reported devices have displayed low yield and lifetimes and this paper presents two strategies to improve these aspects of their performance. The first one involves reducing the critical area, which increased both the electrode yield and lifetimes. The second element utilised test structures, targeted at identifying failure mechanisms, which helped facilitate the materials/design modifications required to make the devices more robust
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