Dynamics of Heavy Rain Spells over India during 2005

High-impact mesoscale weather events, occurring in different parts of India in all seasons, lead to major weather and climate related disasters. In view of this, an attempt has been made in the present study to understand the dynamics of atmospheric circulation over the Indian region (50˚E-100˚E and EQ-30˚N) during super active monsoon period 21st-30th June and 22nd-31st July 2005 using NCEP/NCAR reanalyzed daily winds (u and v), temperature (T) from surface to 200 hPa to compute the divergence (D), vorticity , vertical velocity ,static stability and heat source (QH). (p) profiles clearly indicate the unstable zone between 850 to 650 hPa. The necessary condition of barotropic instability and condition of baroclinic instability are also satisfied in the layer 850- 650 hPa for all the active monsoon days. Further, zonal (u) and meridional (v) winds, are examined in the zonal (x-p) and meridional (y-p) planes. It is noticed that there exist low level cyclonic circulations in the boundary layer over major portion of the country and abnormal increase in the meridional wind in the lower and middle troposphere. Significant increase in the cyclonic vorticity upto 300 hPa and the upward motion throughout in the troposphere with maximum value around 700 to 500 hPa and positive heat source explain the possibility of highly convective and unstable mid-tropospheric zone. The study indicates that there are few mesoscale systems embedded in the synoptic scale system that are already present in the large-scale monsoon circulation

Possible factors that control calcite dissolution in the western tropical Indian Ocean

Calcite dissolution in marine sediments is known to be driven by the degree of saturation state with respect to calcium carbonate, of overlying bottom waters. Three paleocarbonateion proxies, planktonic foraminifer size index, shell weight and calcite crystallinity applied to a set of core top samples reveal that calcite dissolution commences from 2250m onwards and intensifies at around 3900m water depth in the Western Tropical Indian Ocean 1. It was proposed earlier that carbonate dissolution can be caused due to acidification of pore water 2. It is shown that shell weights of the foraminifera species Pulleniatina obliquiloculata indicate that this intense dissolution observed at 3900m was caused due to undersaturation of CO3= in the bottom waters in the Indian Ocea

Aerosol perturbations related to volcanic eruptions during the past few centuries as recorded in an ice core from the Central Dronning Maud Land, Antarctica

High-resolution glacio-chemical analyses were carried out in a 62.2 m long ice core recovered from the Central Dronning Maud Land, East Antarctica, to evaluate temporal changes in environmental characteristics during the past five centuries. The sulphate (SO 4 2-) content within the core varied between 15 and 377 ppb, whereas the sodium (Na +) and chloride (Cl -) content fluctuated widely from 7 to 500 ppb and 25 to 1461 ppb respectively. The computed non-sea-salt sulphate (nssSO 4 2-) record reveals the existence of several outstanding peaks that can be attributed to the sulphate aerosol deposition during large volcanic events as recorded in Antarctica and elsewhere. Major volcanic events identified at the core site include: Mt Pinatubo (1991), Agung (1963), Krakatau/Tarawera (1883/1886), Tambora (1815) and Huaynaputina (1600) among several other moderate events. Comparison of our nssSO 4 2- record with that of ice core records from Greenland reveals analogous sulphate deposition during certain major volcanic events, demonstrating the interhemispheric transport of aerosols during large volcanic eruptions. Relatively high Cl -/Na + ratio throughout the core (mean 3.1) compared to that of the sea water ratio implies additional sources of Cl -, most likely due to the intense scavenging of gaseous Cl - in the lower atmosphere

Structured reporting: if, why, when, how—and at what expense? Results of a focus group meeting of radiology professionals from eight countries

Purpose: To determine why, despite growing evidence that radiologists and referring physicians prefer structured reporting (SR) to free text (FT) reporting, SR has not been widely adopted in most radiology departments. Methods: A focus group was formed consisting of 11 radiology professionals from eight countries. Eight topics were submitted for discussion. The meeting was videotaped, transcribed, and analyzed according to the principles of qualitative healthcare research. Results: Perceived advantages of SR were facilitation of research, easy comparison, discouragement of ambiguous reports, embedded links to images, highlighting important findings, not having to dictate text nobody will read, and automatic translation of teleradiology reports. Being compelled to report within a rigid frame was judged unacceptable. Personal convictions appeared to have high emotional value. It was felt that other healthcare stakeholders would impose SR without regard to what radiologists thought of it. If the industry were to provide ready-made templates for selected examinations, most radiologists would use them. Conclusion: If radiologists can be convinced of the advantages of SR and the risks associated with failing to participate actively in its implementation, they will take a positive stand. The industry should propose technology allowing SR without compromising accuracy, completeness, workflows, and cost-benefit balance

Minimization of phonon-tunneling dissipation in mechanical resonators

Micro- and nanoscale mechanical resonators have recently emerged as ubiquitous devices for use in advanced technological applications, for example in mobile communications and inertial sensors, and as novel tools for fundamental scientific endeavors. Their performance is in many cases limited by the deleterious effects of mechanical damping. Here, we report a significant advancement towards understanding and controlling support-induced losses in generic mechanical resonators. We begin by introducing an efficient numerical solver, based on the "phonon-tunneling" approach, capable of predicting the design-limited damping of high-quality mechanical resonators. Further, through careful device engineering, we isolate support-induced losses and perform the first rigorous experimental test of the strong geometric dependence of this loss mechanism. Our results are in excellent agreement with theory, demonstrating the predictive power of our approach. In combination with recent progress on complementary dissipation mechanisms, our phonon-tunneling solver represents a major step towards accurate prediction of the mechanical quality factor.Comment: 12 pages, 4 figure

Quark-antiquark potential in AdS at one loop

We derive an exact analytical expression for the one-loop partition function of a string in AdS_5xS^5 background with world-surface ending on two anti-parallel lines. All quantum fluctuations are shown to be governed by integrable, single-gap Lame' operators. The first strong coupling correction to the quark-antiquark potential, as defined in N=4 SYM, is derived as the sum of known mathematical constants and a one-dimensional integral representation. Its full numerical value can be given with arbitrary precision and confirms a previous result.Comment: 16 pages. Typos corrected, minor change

Measuring V_ub and probing SUSY with double ratios of purely leptonic decays of B and D mesons

The experimental prospects for precise measurements of the leptonic decays B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are very promising. Double ratios involving four of these decays can be defined in which the dependence on the values of the decay constants is essentially eliminated, thus enabling complementary measurements of the CKM matrix element V_ub with a small theoretical error. We quantify the experimental error in a possible future measurement of |V_ub| using this approach, and show that it is competitive with the anticipated precision from the conventional approaches. Moreover, it is shown that such double ratios can be more effective than the individual leptonic decays as a probe of the parameter space of supersymmetric models. We emphasize that the double ratios have the advantage of using |V_ub| as an input parameter (for which there is experimental information), while the individual decays have an uncertainty from the decay constants (e.g. f_B_s), and hence a reliance on theoretical techniques such as lattice QCD.Comment: 21 pages, 4 figure

Cost-Effectiveness of a Chemoprophylactic Intervention with Single Dose Rifampicin in Contacts of New Leprosy Patients

In 2008, 249,007 new leprosy patients were detected in the world. It therefore remains necessary to develop new and effective interventions to interrupt the transmission of M. leprae. We assessed the economic benefits of single dose rifampicin (SDR) for contacts as chemoprophylactic intervention in the control of leprosy. The study is based on a large trial including 21,711 contacts of 1,037 patients with newly diagnosed leprosy. We gave a single dose of rifampicin or placebo to contacts and followed them up for four years. The main outcome measure was the development of clinical leprosy. The cost effectiveness was expressed in US dollars per prevented leprosy case. Chemoprophylaxis with SDR for preventing leprosy among contacts of leprosy patients is cost-effective at all contact levels and thereby a cost-effective prevention strategy. In total $6,009 was invested and 38 leprosy cases were prevented after 2 years, costing$158 per prevented leprosy case. Implementation studies are necessary to establish whether this intervention is acceptable and feasible in other leprosy endemic areas of the world