The Mesh Archetype

A parallel program archetype [2] aids in the development of reliable, efficient parallel applications with common computation/communication structures by providing development methods and code libraries specific to the structure. This document presents an archetype for mesh-spectral computations. It describes the common structure captured by the archetype abstraction, discusses a parallelization strategy for such computations, documents our code library to support this parallelization strategy, and presents a collection of tutorial example application programs

Spatially resolving the atmosphere of the non-Mira-type AGB star SW Vir in near-infrared molecular and atomic lines with VLTI/AMBER

We present a near-infrared spectro-interferometric observation of the non-Mira-type, semiregular asymptotic giant branch star SW Vir. Our aim is to probe the physical properties of the outer atmosphere with spatially resolved data in individual molecular and atomic lines. We observed SW Vir in the spectral window between 2.28 and 2.31 micron with the near-infrared interferometric instrument AMBER at ESO's Very Large Telescope Interferometer (VLTI). Thanks to AMBER's high spatial resolution and high spectral resolution of 12000, the atmosphere of SW Vir has been spatially resolved not only in strong CO first overtone lines but also in weak molecular and atomic lines of H2O, CN, HF, Ti, Fe, Mg, and Ca. Comparison with the MARCS photospheric models reveals that the star appears larger than predicted by the hydrostatic models not only in the CO lines but also even in the weak molecular and atomic lines. We found that this is primarily due to the H2O lines (but also possibly due to the HF and Ti lines) originating in the extended outer atmosphere. Although the H2O lines manifest themselves very little in the spatially unresolved spectrum, the individual rovibrational H2O lines from the outer atmosphere can be identified in the spectro-interferometric data. Our modeling suggests an H2O column density of 10^{19}--10^{20} cm^{-2} in the outer atmosphere extending out to ~2 Rstar. Our study has revealed that the effects of the nonphotospheric outer atmosphere are present in the spectro-interferometric data not only in the strong CO first overtone lines but also in the weak molecular and atomic lines. Therefore, analyses of spatially unresolved spectra, such as for example analyses of the chemical composition, should be carried out with care even if the lines appear to be weak.Comment: 8 pages, 6 figures, accepted for publication in Astronomy and Astrophysic

Parallel Program Archetypes

A parallel program archetype is an abstraction that captures the common features of a class of problems with similar computational structure and combines them with a parallelization strategy to produce a pattern of dataflow and communication. Such abstractions are useful in application development, both as a conceptual framework and as a basis for tools and techniques. This paper describes an approach to parallel application development based on archetypes and presents two example archetypes with applications

Assessing the Market for Poultry Litter in Georgia: Are Subsidies Needed to Protect Water Quality?

Concerns about nutrient loads into our waters have focused attention on poultry litter applications. Like many states with a large poultry industry, Georgia recently designed a subsidy program to facilitate the transportation of poultry litter out of vulnerable watersheds. This paper uses a transportation model to examine the necessity of a poultry litter subsidy to achieve water protection goals in Georgia. We also demonstrate the relationship between diesel and synthetic fertilizer prices and the value of poultry litter. Results suggest that a well functioning market would be able to remove excess litter from vulnerable watersheds in the absence of a subsidy.fertilizer, phosphorous, poultry litter, subsidy, transportation model, water quality, Environmental Economics and Policy, Marketing, Q12, Q13, Q25, Q53,

Impact of hypnosis on psychophysiological measures: A scoping literature review.

Exploring psychophysiological changes during hypnosis can help to better understand the nature and extent of the hypnotic phenomenon by characterizing its influence on the autonomic nervous system (ANS), in addition to its central brain effects. Hypnosis is thought to induce a relaxation response, yet studies using objective psychophysiological measures alongside hypnosis protocols show various results. We review this literature and clarify the effects of hypnosis on psychophysiological indices of ANS activity and more specifically of the stress/relaxation response, such as heart rate variability and electrodermal activity. Studies reporting psychophysical measures during hypnosis were identified by a series of Pubmed searches. Data was extracted with an interest for the influence of hypnotizability and effects of specific suggestions or tasks on the findings. We found 49 studies comprising 1315 participants, 45 concerning healthy volunteers and only 4 on patients. Sixteen compared high vs. low hypnotizable people; 30 measured heart rate, 18 measured heart rate variability, 25 electrodermal activity, and 23 respiratory signals as well as other physiological parameters. Globally, results converge to show reductions in sympathetic responses and/or increases in parasympathetic tone under hypnosis. Several methodological limitations are underscored, such as older studies (N = 16) using manual analyses, small sample sizes (<30, N = 31), as well as uncontrolled multiple comparisons. Nevertheless, we confirm that hypnosis leads to a physiological relaxation response and highlight promising avenues for this research. Suggestions are made for guiding future work in this field

Extended skyrmion lattice scattering and long-time memory in the chiral magnet Fe1−x_{1-x}Cox_xSi

Small angle neutron scattering measurements on a bulk single crystal of the doped chiral magnet Fe$_{1-x}$Co$_x$Si with $x$=0.3 reveal a pronounced effect of the magnetic history and cooling rates on the magnetic phase diagram. The extracted phase diagrams are qualitatively different for zero and field cooling and reveal a metastable skyrmion lattice phase outside the A-phase for the latter case. These thermodynamically metastable skyrmion lattice correlations coexist with the conical phase and can be enhanced by increasing the cooling rate. They appear in a wide region of the phase diagram at temperatures below the $A$-phase but also at fields considerably smaller or higher than the fields required to stabilize the A-phase

1000–32 Spontaneous Evolution of Nonocclusive Coronary Dissection After PTCA: A 6 Month Angiographic Follow-up Study

We have previously shown that, when good distal flow is maintained, dissection after PTCA has a favourable short term (24 hrs) evolution and does not require bail-out interventions or CABG.To evaluate the long term (6 months) clinical and angiographic evolution of non occlusive dissection, we submitted 129 consecutive patients (103 male, mean age 53±11 yrs) undergoing elective PTCA (147 lesions, 66 LAD, 49 CX, 32 DX) to repeat angiography 24 hrs and 6 months after the procedure. Lesions were measured by QCA and coronary dissection was graded using the NHLBI classification (types A-E; Huber Am J Cardiol 1991;68: 467). Mean stenosis was 85±11% before and 25±7% immediately after PTCA (p<0.001). Residual stenosis was not significantly different at the 24 hrs restudy (24±9%). Non occlusive coronary dissection (flow TIMI grade 3 in all pts) was seen in 49/147 lesions (33%) and evolved as follows:Dissection (tot)Immediate 49 (33%)24 hrs 41 (28%)6 months 18 (12%)A332710B1085C442D221At the 6 month follow-up study, restenosis was seen in 51/147 lesions (34%), of which 5/49 (10%) had dissection and 46/106 (43%) did not. No cardiovascular events or recurrence of symptoms were recorded in the absence of restenosis.Therefore 1) nonocclusive dissection after PTCA usually improves after 6 month; 2) in the absence of flow impairment and ischemia this complication does not require any further intervention; 3) non occlusive dissection is not associated with increased incidence of restenosis

Magnetic Fluctuations, Precursor Phenomena and Phase Transition in MnSi under Magnetic Field

The reference chiral helimagnet MnSi is the first system where skyrmion lattice correlations have been reported. At zero magnetic field the transition at $T_C$ to the helimagnetic state is of first order. Above $T_C$, in a region dominated by precursor phenomena, neutron scattering shows the build up of strong chiral fluctuating correlations over the surface of a sphere with radius $2\pi/\ell$, where $\ell$ is the pitch of the helix. It has been suggested that these fluctuating correlations drive the helical transition to first order following a scenario proposed by Brazovskii for liquid crystals. We present a comprehensive neutron scattering study under magnetic fields, which provides evidence that this is not the case. The sharp first order transition persists for magnetic fields up to 0.4 T whereas the fluctuating correlations weaken and start to concentrate along the field direction already above 0.2 T. Our results thus disconnect the first order nature of the transition from the precursor fluctuating correlations. They also show no indication for a tricritical point, where the first order transition crosses over to second order with increasing magnetic field. In this light, the nature of the first order helical transition and the precursor phenomena above $T_C$, both of general relevance to chiral magnetism, remain an open question