396 research outputs found

    Probing Disordered Substrates by Imaging the Adsorbate in its Fluid Phase

    Get PDF
    Several recent imaging experiments access the equilibrium density profiles of interacting particles confined to a two-dimensional substrate. When these particles are in a fluid phase, we show that such data yields precise information regarding substrate disorder as reflected in one-point functions and two-point correlations of the fluid. Using Monte Carlo simulations and replica generalizations of liquid state theories, we extract unusual two-point correlations of time-averaged density inhomogeneities induced by disorder. Distribution functions such as these have not hitherto been measured but should be experimentally accessible.Comment: 10 pages revtex 4 figure

    Servicing Delay Sensitive Pervasive Communication Through Adaptable Width Channelization for Supporting Mobile Edge Computing

    Get PDF
    Over the last fifteen years, wireless local area networks (WLANs) have been populated by large variety of pervasive devices hosting heterogeneous applications. Pervasive Edge computing encouraged more distributed network applications for these devices, eliminating the round-trip to help in achieving zero latency dream. However, These applications require significantly variable data rates for effective functioning, especially in pervasive computing. The static bandwidth of frequency channelization in current WLANs strictly restricts the maximum achievable data rate by a network station. This static behavior spawns two major drawbacks: under-utilization of scarce spectrum resources and less support to delay sensitive applications such as voice and video.To this point, if the computing is moved to the edge of the network WLANs to reduce the frequency of communication, the pervasive devices can be provided with better services during the communication and networking. Thus, we aim to distribute spectrum resources among pervasive resources based upon delay sensitivity of applications while simultaneously maintaining the fair channel access semantics of medium access control (MAC) layer of WLANs. Henceforth, ultra-low latency, efficiency and reliability of spectrum resources can be assured. In this paper, two novel algorithms have been proposed for adaptive channelization to offer rational distribution of spectrum resources among pervasive Edge nodes based on their bandwidth requirement and assorted ambient conditions. The proposed algorithms have been implemented on a real test bed of commercially available universal software radio peripheral (USRP) devices. Thorough investigations have been carried out to enumerate the effect of dynamic bandwidth channelization on parameters such as medium utilization, achievable throughput, service delay, channel access fairness and bit error rates. The achieved empirical results demonstrate that we can optimally enhance the network-wide throughput by almost 30% using channels of adaptable bandwidths

    STM Imaging of Flux Line Arrangements in the Peak Effect Regime

    Get PDF
    We present the results of a study of vortex arrangements in the peak-effect regime of 2H-NbSe_2 by scanning tunneling microscopy. By slowly increasing the temperature in a constant magnetic field, we observed a sharp transition from collective vortex motion to positional fluctuations of individual vortices at the temperature which coincides with the onset of the peak effect in ac-susceptibility. We conclude that the peak effect is a disorder driven transition, with the pinning energy winning from the elastic energy.Comment: 4 pages, 4 figures included Manuscript has been submitte

    Dendritic flux patterns in MgB2 films

    Full text link
    Magneto-opitcal studies of a c-oriented epitaxial MgB2 film with critical current density 10^7 A/cm^2 demonstrate a breakdown of the critical state at temperatures below 10 K [cond-mat/0104113]. Instead of conventional uniform and gradual flux penetration in an applied magnetic field, we observe an abrupt invasion of complex dendritic structures. When the applied field subsequently decreases, similar dendritic structures of the return flux penetrate the film. The static and dynamic properties of the dendrites are discussed.Comment: Accepted to Supercond. Sci. Techno

    Low field vortex matter in YBCO: an atomic beam magnetic resonance study

    Full text link
    We report measurements of the low field structure of the magnetic vortex lattice in an untwinned YBCO single-crystal platelet. Measurements were carried out using a novel atomic beam magnetic resonance (ABMR) technique. For a 10.7 G field applied parallel to the c-axis of the sample, we find a triangular lattice with orientational order extending across the entire sample. We find the triangular lattice to be weakly distorted by the a-b anisotropy of the material and measure a distortion factor, f = 1.16. Model-experiment comparisons determine a penetration depth, lambda_ab = 140 (+-20) nm. The paper includes the first detailed description of the ABMR technique. We discuss both technical details of the experiment and the modeling used to interpret the measurements.Comment: 44 pages, 13 figures, submitted to Phys. Rev. B Revision includes Postscript wrapped figures + minor typo

    Haematological, lipid profile and other biochemical parameters in normal and hypertensive subjects among the population of the eastern province of Saudi Arabia

    Get PDF
    Objective: To determine the lipid profile complete blood count and other biochemical parameters in normotensive and hypertensive individuals. Design: Cross-sectional population-based epidemiological household survey. Setting: Population sample of the Eastern Province of Saudi Arabia. Results: Hypertensive individuals had significantly higher mean levels of glucose, Tc, LDL-c, HDL-c, triglycerides and HBAIc, compared to normotensive individuals while there were no significant difference in the mean levels of Apo AI and Apo B. Within the same group there were variations in the levels of certain parameters between male and female. While the mean levels of haemoglobin, WBC and platelets were significantly higher in the hypertensive group compared to normotensive, there were no significant differences between these two groups in the levels of RBC, MCV, HCT, MCH and MCHC. However, the mean levels haemoglobin, RBC count and HCT were significantly higher in male compared to female within the same group with no significant difference in levels of WBC, MCV, MCH and MCHC. Furthermore, the mean concentration of platelets was significantly higher in females compared to male within the same group. Hypertensive individuals had significantly higher serum sodium, chloride and calcium levels but a significantly lower potassium level when compared to normotensive with no siginificant differences between male and female within the same group. Conclusion: The lipid and electrolyte profile of hypertensive individuals differ from that of normotensive individuals in this population. This study has contributed towards establishing the normal values for a number of parameters involved in the aetiology of cardiovascular diseases in the population of Eastern province. East African Medical Journal Vol. 83(1) 2006: 44-4

    A compact high gain opamp for Bio-medical applications in 45nm CMOS technology

    Get PDF
    In this paper a low opamp compensation technique suitable for the bio-medical application has been proposed and intuitive explained the existing compensation techniques. The Present technique relies on the passive damping factor control rather power hungry damping. Implemented in 45nm CMOS technology and simulated with Spectre. Simulation results shows that 100dB dc gain, well compensated 25MHz bandwidth opamp while driving a 1pF capacitive load. Draws with 12uW power consumption from 1V supply and occupying 0.004875mm2 silicon area

    Selective serotonin reuptake inhibitors in the treatment of generalized anxiety disorder

    Get PDF
    Selective serotonin reuptake inhibitors have proven efficacy in the treatment of panic disorder, obsessive–compulsive disorder, post-traumatic stress disorder and social anxiety disorder. Accumulating data shows that selective serotonin reuptake inhibitor treatment can also be efficacious in patients with generalized anxiety disorder. This review summarizes the findings of randomized controlled trials of selective serotonin reuptake inhibitor treatment for generalized anxiety disorder, examines the strengths and weaknesses of other therapeutic approaches and considers potential new treatments for patients with this chronic and disabling anxiety disorder

    Local threshold field for dendritic instability in superconducting MgB2 films

    Full text link
    Using magneto-optical imaging the phenomenon of dendritic flux penetration in superconducting films was studied. Flux dendrites were abruptly formed in a 300 nm thick film of MgB2 by applying a perpendicular magnetic field. Detailed measurements of flux density distributions show that there exists a local threshold field controlling the nucleation and termination of the dendritic growth. At 4 K the local threshold field is close to 12 mT in this sample, where the critical current density is 10^7 A/cm^2. The dendritic instability in thin films is believed to be of thermo-magnetic origin, but the existence of a local threshold field, and its small value are features that distinctly contrast the thermo-magnetic instability (flux jumps) in bulk superconductors.Comment: 6 pages, 6 figures, submitted to Phys. Rev.
    • …
    corecore