2,483 research outputs found

    Acceptance Dependence of Fluctuation in Particle Multiplicity

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    The effect of limiting the acceptance in rapidity on event-by-event multiplicity fluctuations in nucleus-nucleus collisions has been investigated. Our analysis shows that the multiplicity fluctuations decrease when the rapidity acceptance is decreased. We explain this trend by assuming that the probability distribution of the particles in the smaller acceptance window follows binomial distribution. Following a simple statistical analysis we conclude that the event-by-event multiplicity fluctuations for full acceptance are likely to be larger than those observed in the experiments, since the experiments usually have detectors with limited acceptance. We discuss the application of our model to simulated data generated using VENUS, a widely used event generator in heavy-ion collisions. We also discuss the results from our calculations in presence of dynamical fluctuations and possible observation of these in the actual data.Comment: To appear in Int. J. Mod. Phys.

    A rare case report on ovotesticular disorders of sex development (DSD) 46XY variant

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    Ovotestis refers to the histology of a gonad that contains both ovarian follicles and testicular tubular elements. Ovotesticular DSD is a rare condition characterized by mixed ovarian and testicular tissue. Majority have a 46,XX karyotype, 7% have 46,XY karyotype and 10-40% exhibit chromosomal mosaicism. Here, we report the case of a boy with a 46,XY karyotype diagnosed as ovotesticular DSD by gonadal biopsy. A 14 year-old reared as  boy presented with came with ambiguous genitalia with no palpable gonads since birth and developed progressive virilization and gynaecomastia at puberty  having curved phallus with glans, redundant prepucial skin, labia majora and hypoplastic labia minora, rudimentary vagina with small introitus was present. External urethral meatus present lower down the vestibular area above the introitus. Testicles not felt. USG - revealed definite uterus behind Urinary bladder with small intraabdominal testes. Karyotyping - 46XY Barr body present. Diagnostic laparoscopy showed   Uterus with bilateral fallopian tubes. Bilateral gonadectomy done. Histopathologic examination report revealed bilateral gonadoblastoma in testis and ovotestis. Patient underwent transperitoneal excision of Mullerian remnants. Patient was discharged with an advice of cap testosterone undecanoate and regular follow up. We highlight the importance of histological and cytogenetic investigation in DSD

    Influence of LD slag on iron ore sinter properties and productivity

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    Large amounts of slags from steel plants are produced through basic oxygen furnace and LD furnace. The main purpose of LD process is to convert the molten pig iron and steel scraps into high quality steel. In India, the generation of steel melting slag is over 4 to 4.5 Mt per annum. The amount of steel slags from different steel industries are 150–200 kg/t of steel produced. Disposal of large quantities of slag becomes a big environmental concern. JSW Steel Limited is a 7.0 Mtpa integrated steel plant and produces 3200 tons of total steel making slag per day and in that LD slag is 2000 to 2500 t/day. This LD slag consists of 45.75% CaO, 22.0 % Fe and 8.22% MgO. Thus, recycling of LD slag through the sintering process recovers lime, iron and magnesia and thereby saving of flux material and iron ore. Due to high content of CaO one can replace LD slag by limestone in sintering process. Detail investigation was carried out through lab scale studies for estimating the maximum permissible limits of usage of LD slag in sinter making and to know the influence of LD slag addition on sinter productivity and properties. Experiments were conducted using the LD slag in sinter making from 0 to 60kg/t of sinter. FeO content of the sinter decreased, sinter productivity increased with increase in LD slag addition. Decrease in FeO content is due to decrease in sinter bed temperature and increase in productivity is due to decrease in LOI content of the sinter mix and absence of weight loss due to calcination process. The sinter strength and RDI of the sinter deteriorated due to non availability of free CaO in LD slag and this reduces the formation of calcium ferrites phase and more Fe2O3 remains as free phase due to less reaction with CaO. From the test results it was found that 30 to 35 kg LD slag can be used per ton of sinter to get desired properties of the sinter

    Energy efficient cooperative computing in mobile wireless sensor networks

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    Advances in future computing to support emerging sensor applications are becoming more important as the need to better utilize computation and communication resources and make them energy efficient. As a result, it is predicted that intelligent devices and networks, including mobile wireless sensor networks (MWSN), will become the new interfaces to support future applications. In this paper, we propose a novel approach to minimize energy consumption of processing an application in MWSN while satisfying a certain completion time requirement. Specifically, by introducing the concept of cooperation, the logics and related computation tasks can be optimally partitioned, offloaded and executed with the help of peer sensor nodes, thus the proposed solution can be treated as a joint optimization of computing and networking resources. Moreover, for a network with multiple mobile wireless sensor nodes, we propose energy efficient cooperation node selection strategies to offer a tradeoff between fairness and energy consumption. Our performance analysis is supplemented by simulation results to show the significant energy saving of the proposed solution

    Inelastic effects in electron transport studied with wave packet propagation

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    A time-dependent approach is used to explore inelastic effects during electron transport through few-level systems. We study a tight-binding chain with one and two sites connected to vibrations. This simple but transparent model gives insight about inelastic effects, their meaning and the approximations currently used to treat them. Our time-dependent approach allows us to trace back the time sequence of vibrational excitation and electronic interference, the ibrationally introduced time delay and the electronic phase shift. We explore a full range of parameters going from weak to strong electron-vibration coupling, from tunneling to contact, from one-vibration description to the need of including all vibrations for a correct description of inelastic effects in transport. We explore the validity of single-site resonant models as well as its extension to more sites via molecular orbitals and the conditions under which multi-orbital, multi-vibrational descriptions cannot be simplified. We explain the physical meaning of the spectral features in the second derivative of the electron current with respect to the bias voltage. This permits us to nuance the meaning of the energy value of dips and peaks. Finally, we show that finite-band effects lead to electron back-scattering off the molecular vibrations in the regime of high-conductance, although the drop in conductance at the vibrational threshold is rather due to the rapid variation of the vibronic density of states.Comment: 38 pages, 14 figure

    A tachyonic extension of the stringy no-go theorem

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    We investigate the tachyon-dilaton-metric system to study the "graceful exit" problem in string theoretic inflation, where tachyon plays the role of the scalar field. From the phase space analysis, we find that the inflationary phase does not smoothly connect to a Friedmann-Robertson-Walker (FRW) expanding universe, thereby providing a simple tachyonic extension of the recently proved stringy no-go theorem.Comment: TeX file (PHYZZX), 10 pages, change in the title, many changes in the text (the version to appear in Phys. Rev. D

    Microstructure Analysis of Aluminum Alloy and Copper Alloy Circular Shells After Multiaxial Plastic Buckling

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    Aluminum and copper cylindrical shells were plastically buckled under quasi-static and dynamic loading conditions with an Absorption Compression-Torsion Plasticity (ACTP: Patent No. WO 2005090822) combined mechanical testing device. Optical microscopy and transmission electron microscopy (TEM) analysis were used to study the microscopic evolutions in the mechanically buckled aluminum and copper alloy samples. Optical microscopy showed evidence of the presence of second-phase particles in both the aluminum and copper alloys samples. Under dynamic loading aluminum samples showed more energy absorption as compared to copper samples. Material flow lines were more pronounced in the copper samples when observed by optical microscopy. The evidence that supports the increased energy absorption in the aluminum cylindrical shells can be supported by the TEM analysis more than the optical microscopy analysis. The TEM results showed highly oriented textured morphology with the presence of few dislocation cells structures and sub-structures

    Planetoid strings : solutions and perturbations

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    A novel ansatz for solving the string equations of motion and constraints in generic curved backgrounds, namely the planetoid ansatz, was proposed recently by some authors. We construct several specific examples of planetoid strings in curved backgrounds which include Lorentzian wormholes, spherical Rindler spacetime and the 2+1 dimensional black hole. A semiclassical quantisation is performed and the Regge relations for the planetoids are obtained. The general equations for the study of small perturbations about these solutions are written down using the standard, manifestly covariant formalism. Applications to special cases such as those of planetoid strings in Minkowski and spherical Rindler spacetimes are also presented.Comment: 24 pages (including two figures), RevTex, expanded and figures adde

    Long-term impacts of integrated nutrient management with equivalent nutrient doses to mineral fertilization on soil organic carbon sequestration in a sub-tropical Alfisol of India

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    Limited evidence is available on carbon sequestration potential of long-term integrated nutrient management (INM) versus mineral fertilization, when equivalent amounts of nutrients were added. Hence, this study was carried out to understand the impact of 60 years of INM with adjusted nutrient doses and mineral fertilization in an Alfisol in a maize (Zea maysL.)-wheat (Triticum aestivumL.) system on soil organic carbon (SOC) sequestration in surface (0-30 cm) and deep (30-60 cm) soil layers. Conventional tillage was done twice before sowing of both maize and wheat using a spade. In farmyard manure (FYM) and lime treated plots (FYMP'K'L: plots with nitrogen (N) applied in terms of FYM; additional dose of phosphorus (P) and potassium (K) and lime) total SOC concentration was nearly 83% higher than unfertilized control plots. The FYMP'K'L plots had similar to 11% more total SOC concentration than plots treated with mineral fertilizer and lime (NPKL: recommended dose of N, P, K and lime) in the 0-30 cm soil layer. Labile C, including KMnO4-C, was more in plots with FYM than NPKL plots, whereas the recalcitrant C stock was more in NPKL than FYM treated plots. In the 0-60 cm soil layer, the labile C stock was highest in FYMP'K'L plots, but the recalcitrant C stock was highest in NPKL. Total SOC accumulation rate (over unfertilized control plots) was highest for FYMP'K'L plots (0.38 Mg ha(-1 )year(-1)) in the surface soil layer, whereas SOC sequestration rate was highest in NPKL plots (0.18 Mg ha(-1 )year(-1)) in the deep layer and in the 0-60 cm layer. Overall, although NPKL management practice had the highest C sequestration in the 0-60 cm layer, FYMP'K'L had the best CMI and labile C pools. Thus, resource poor farmers need not to use full doses of NPK and FYM for soil C management in the region

    Study of low energy Si5_5^- and Cs^- implantation induced amorphization effects in Si(100)

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    The damage growth and surface modifications in Si(100), induced by 25 keV Si5_5^- cluster ions, as a function of fluence, ϕ\phi, has been studied using atomic force microscopy (AFM) and channeling Rutherford backscattering spectrometry (CRBS). CRBS results indicate a nonlinear growth in damage from which it has been possible to get a threshold fluence, ϕ0\phi_0, for amorphization as 2.5×10132.5\times 10^{13} ions-cm2^{-2}. For ϕ\phi below ϕ0\phi_0, a growth in damage as well as surface roughness has been observed. At a ϕ\phi of 1×10141\times 10^{14} ions-cm2^{-2}, damage saturation coupled with a much reduced surface roughness has been found. In this case a power spectrum analysis of AFM data showed a significant drop, in spectral density, as compared to the same obtained for a fluence, ϕ<ϕ0\phi < \phi_0. This drop, together with damage saturation, can be correlated with a transition to a stress relaxed amorphous phase. Irradiation with similar mass Cs^- ions, at the same energy and fluence, has been found to result in a reduced accumulation of defects in the near surface region leading to reduced surface features.Comment: 7 pages, 4 figure
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