Effect of secondary swirl in supersonic gas and plasma flows in self-vacuuming vortex tube

This article presents the results of simulation for a special type of vortex tubes - self-vacuuming vortex tube (SVVT), for which extreme values of temperature separation and vacuum are realized. The main results of this study are the flow structure in the SVVT and energy loss estimations on oblique shock waves, gas friction, instant expansion and organization of vortex bundles in SVVT.Comment: 6 pages, 5 figure

Improving the dynamical overlap algorithm

We present algorithmic improvements to the overlap Hybrid Monte Carlo algorithm, including preconditioning techniques and improvements to the correction step, used when one of the eigenvalues of the Kernel operator changes sign, which is now O(\Delta t^2) exact.Comment: 6 pages, 3 figures; poster contribution at Lattice 2005(Algorithms and machines

The journals of importance to UK clinicians: A questionnaire survey of surgeons

Background: Peer-reviewed journals are seen as a major vehicle in the transmission of research findings to clinicians. Perspectives on the importance of individual journals vary and the use of impact factors to assess research is criticised. Other surveys of clinicians suggest a few key journals within a specialty, and sub-specialties, are widely read. Journals with high impact factors are not always widely read or perceived as important. In order to determine whether UK surgeons consider peer-reviewed journals to be important information sources and which journals they read and consider important to inform their clinical practice, we conducted a postal questionnaire survey and then compared the findings with those from a survey of US surgeons. Methods: A questionnaire survey sent to 2,660 UK surgeons asked which information sources they considered to be important and which peer-reviewed journals they read, and perceived as important, to inform their clinical practice. Comparisons were made with numbers of UK NHSfunded surgery publications, journal impact factors and other similar surveys. Results: Peer-reviewed journals were considered to be the second most important information source for UK surgeons. A mode of four journals read was found with academics reading more than non-academics. Two journals, the BMJ and the Annals of the Royal College of Surgeons of England, are prominent across all sub-specialties and others within sub-specialties. The British Journal of Surgery plays a key role within three sub-specialties. UK journals are generally preferred and readership patterns are influenced by membership journals. Some of the journals viewed by surgeons as being most important, for example the Annals of the Royal College of Surgeons of England, do not have high impact factors. Conclusion: Combining the findings from this study with comparable studies highlights the importance of national journals and of membership journals. Our study also illustrates the complexity of the link between the impact factors of journals and the importance of the journals to clinicians. This analysis potentially provides an additional basis on which to assess the role of different journals, and the published output from research

Magnetic field detection in the B2Vn star HR 7355

The B2Vn star HR 7355 is found to be a He-rich magnetic star. Spectropolarimetric data were obtained with FORS1 at UT2 on Paranal observatory to measure the disk-averaged longitudinal magnetic field at various phases of the presumed 0.52 d cycle. A variable magnetic field with strengths between B_z = -2200 and +3200G was found, with confidence limits of 100 to 130G. The field topology is that of an oblique dipole, while the star itself is seen about equator-on. In the intensity spectra the HeI-lines show the typical equivalent width variability of He-strong stars, usually attributed to surface abundance spots. The amplitudes of the equivalent width variability of the HeI lines are extraordinarily strong compared to other cases. These results not only put HR 7355 unambiguously among the early-type magnetic stars, but confirm its outstanding nature: With v sin i = 320 km/s the parameter space in which He-strong stars are known to exist has doubled in terms of rotational velocity.Comment: 6 pages, 5 figures, 1 Table. Accepted for publication in MNRAS Letter

Impact of low-input meadows on arthropod diversity at habitat and landscape level

In Switzerland, in order to preserve and enhance arthopod diversity in grassland ecosystems (among others), farmers had to convert at least 7 % of their land to ecological compensation areas – ECA. Major ECA are low input grassland, traditional orchards, hedges and wild flower strips. In this paper the difference in species assemblages of 3 arthropod groups, namely spiders, carabid beetles and butterflies between intensively managed and low input meadows is stressed by means of multivariate statistics. On one hand, the consequences of these differences are analysed at the habitat level to promote good practices for the arthropod diversity in grassland ecosystems. On the other hand, the contribution of each meadow type to the regional diversity is investigated to widen the analysis at the landscape level

Benefits from clinicians and healthcare organisations engaging in research

In Editor’s Choice, Godlee supports and re-emphasises the positive points about National Institute for Health Research (NIHR) clinical research networks that are made in Gulland’s article.1 2 We welcome this support for research networks and for the part they can play in a more fully integrated research and healthcare system. Research engagement by clinicians and healthcare organisations is widely held to improve health services performance. However, we found the issue to be complex in our review conducted for the NIHR Health Services and Delivery Research (HS&DR) Programme in 2012-13.3 Thirty three papers were included in the analysis, and 28 were positive about improved performance, although only seven identified improved outcomes rather than improved processes. Diverse mechanisms contributed to these improvements. In a subsequent article we consider more recent evidence,4 including that UK NHS trusts active in research have lower risk adjusted mortality for acute admissions.5 Increased attention to this issue covers not only clinician participation but also organisational developments in the NIHR and NHS, such as Collaborations for Leadership in Applied Health Research and Care (CLAHRC) and Academic Health Science Networks (AHSNs).6 7 These seek to promote better integration of research and healthcare systems by strengthening research networks, developing research capacity, and ensuring that healthcare organisations (both providers and commissioners) see research as an integral component of their overall structure. Such initiatives need to be linked to further empirical analysis that considers not only the research engagement of all relevant actors but also the organisational determinants of the impact on practice of such engagement

Simulation of physical properties of the chalcogenide glass As2S3 using a density-functional-based tight-binding method

We have used a density-functional-based tight-binding method in order to create structural models of the canonical chalcogenide glass, amorphous As2S3. The models range from one containing defects that are both chemical (homopolar bonds) and topological (valence-alternation pairs) in nature to one that is defect-free (stoichiometric). The structural, vibrational, and electronic properties of the simulated models are in good agreement with experimental data where available. The electronic densities of states obtained for all models show clean optical band gaps. A certain degree of electron-state localization at the band edges is observed for all models, which suggests that photoinduced phenomena in chalcogenide glasses may not necessarily be attributed to the excitation of defects of only one particular kind

Chiral behavior of pseudo-Goldstone boson masses and decay constants in 2+1 flavor QCD

We present preliminary results for the chiral behavior of charged pseudo-Goldstone-boson masses and decay constants. These are obtained in simulations with N_f=2+1 flavors of tree-level, O(a)-improved Wilson sea quarks. In these simulations, mesons are composed of either valence quarks discretized in the same way as the sea quarks (unitary simulations) or of overlap valence quarks (mixed-action simulations). We find that the chiral behavior of the pseudoscalar meson masses in the mixed-action calculations cannot be explained with continuum, partially-quenched chiral perturbation theory. We show that the inclusion of O(a^2) unitarity violations in the chiral expansion resolves this discrepancy and that the size of the unitarity violations required are consistent with those which we observe in the zero-momentum, scalar-isotriplet-meson propagator.Comment: 7 pages, 3 figures, talk by L. Lellouch at the XXV International Symposium on Lattice Field Theory (LATTICE 2007), 30 July - 4 August 2007, Regensburg, German

Polar cap magnetic field reversals during solar grand minima: could pores play a role?

We study the magnetic flux carried by pores located outside active regions with sunspots and investigate their possible contribution to the reversal of the global magnetic field of the Sun. We find that they contain a total flux of comparable amplitude to the total magnetic flux contained in polar caps. The pores located at distances of 40--100~Mm from the closest active region have systematically the correct sign to contribute to the polar cap reversal. These pores can predominantly be found in bipolar magnetic regions. We propose that during grand minima of solar activity, such a systematic polarity trend, akin to a weak magnetic (Babcock-Leighton-like) source term could still be operating but was missed by the contemporary observers due to the limited resolving power of their telescopes.Comment: 11 pages, 9 figures, accepted for publication in Astronomy&Astrophysic