Spatially-Correlated Microstructure and Superconductivity in Polycrystalline Boron-Doped Diamond

Scanning tunneling spectroscopies are performed below 100~mK on nano-crystalline boron-doped diamond films characterized by Transmission Electron Microscopy and transport measurements. We demonstrate a strong correlation between the local superconductivity strength and the granular structure of the films. The study of the spectral shape, amplitude and temperature dependence of the superconductivity gap enables us to differentiate intrinsically superconducting grains that follow the BCS model, from grains showing a different behavior involving the superconducting proximity effect

The Feeling of Color: A Haptic Feedback Device for the Visually Disabled

Tapson J, Gurari N, Diaz J, et al. The Feeling of Color: A Haptic Feedback Device for the Visually Disabled. Presented at the Biomedical Circuits and Systems Conference (BIOCAS), Baltimore, MD.We describe a sensory augmentation system designed to provide the visually disabled with a sense of color. Our system consists of a glove with short-range optical color sensors mounted on its fingertips, and a torso-worn belt on which tactors (haptic feedback actuators) are mounted. Each fingertip sensor detects the observed objectpsilas color. This information is encoded to the tactor through vibrations in respective locations and varying modulations. Early results suggest that detection of primary colors is possible with near 100% accuracy and moderate latency, with a minimum amount of training

Damage spreading and coupling in Markov chains

In this paper, we relate the coupling of Markov chains, at the basis of perfect sampling methods, with damage spreading, which captures the chaotic nature of stochastic dynamics. For two-dimensional spin glasses and hard spheres we point out that the obstacle to the application of perfect-sampling schemes is posed by damage spreading rather than by the survey problem of the entire configuration space. We find dynamical damage-spreading transitions deeply inside the paramagnetic and liquid phases, and show that critical values of the transition temperatures and densities depend on the coupling scheme. We discuss our findings in the light of a classic proof that for arbitrary Monte Carlo algorithms damage spreading can be avoided through non-Markovian coupling schemes.Comment: 6 pages, 8 figure

Interstate Vibronic Coupling Constants Between Electronic Excited States for Complex Molecules

In the construction of diabatic vibronic Hamiltonians for quantum dynamics in the excited-state manifold of molecules, the coupling constants are often extracted solely from information on the excited-state energies. Here, a new protocol is applied to get access to the interstate vibronic coupling constants at the time-dependent density functional theory level through the overlap integrals between excited-state adiabatic auxiliary wavefunctions. We discuss the advantages of such method and its potential for future applications to address complex systems, in particular those where multiple electronic states are energetically closely lying and interact. As examples, we apply the protocol to the study of prototype rhenium carbonyl complexes [Re(CO)$_3$(N,N)(L)]$^{n+}$ for which non-adiabatic quantum dynamics within the linear vibronic coupling model and including spin-orbit coupling have been reported recently.Comment: 36 pages, 7 figures, 4 table

Binary Black-Hole Mergers in Magnetized Disks: Simulations in Full General Relativity

We present results from the first fully general relativistic, magnetohydrodynamic (GRMHD) simulations of an equal-mass black hole binary (BHBH) in a magnetized, circumbinary accretion disk. We simulate both the pre and post-decoupling phases of a BHBH-disk system and both "cooling" and "no-cooling" gas flows. Prior to decoupling, the competition between the binary tidal torques and the effective viscous torques due to MHD turbulence depletes the disk interior to the binary orbit. However, it also induces a two-stream accretion flow and mildly relativistic polar outflows from the BHs. Following decoupling, but before gas fills the low-density "hollow" surrounding the remnant, the accretion rate is reduced, while there is a prompt electromagnetic (EM) luminosity enhancement following merger due to shock heating and accretion onto the spinning BH remnant. This investigation, though preliminary, previews more detailed GRMHD simulations we plan to perform in anticipation of future, simultaneous detections of gravitational and EM radiation from a merging BHBH-disk system.Comment: 5 pages, 5 figure

Importance of cooling in triggering the collapse of hypermassive neutron stars

The inspiral and merger of a binary neutron star (NSNS) can lead to the formation of a hypermassive neutron star (HMNS). As the HMNS loses thermal pressure due to neutrino cooling and/or centrifugal support due to gravitational wave (GW) emission, and/or magnetic breaking of differential rotation it will collapse to a black hole. To assess the importance of shock-induced thermal pressure and cooling, we adopt an idealized equation of state and perform NSNS simulations in full GR through late inspiral, merger, and HMNS formation, accounting for cooling. We show that thermal pressure contributes significantly to the support of the HMNS against collapse and that thermal cooling accelerates its "delayed" collapse. Our simulations demonstrate explicitly that cooling can induce the catastrophic collapse of a hot hypermassive neutron star formed following the merger of binary neutron stars. Thus, cooling physics is important to include in NSNS merger calculations to accurately determine the lifetime of the HMNS remnant and to extract information about the NS equation of state, cooling mechanisms, bar instabilities and B-fields from the GWs emitted during the transient phase prior to BH formation.Comment: 13 pages, 7 figures, matches published versio

Surgical management of hydatid liver cysts: A case report

The discovery of huge and compressing cystic masses on the right liver, associated with right hypochondrium complaints usually presents a diagnostic and management challenge to the surgeon, especially in clinically high risky patients. In this paper we report a case of 65-year old female known diabetic and hypertensive patient presented at Lusaka University Teaching Hospital with chronic right hypochondriac pain and tenderness and was found to have a huge hydatid like cyst of the right liver. The diagnosis was based on the clinical abdominal and ultrasonography findings. The patient underwent a successful cystectomy with partial pericystectomy. The residual cavity was filled with an omental patch. This paper reviews the literature and discusses the pathogenesis, diagnosis and the surgical treatment of Hydatid liver cysts, emphasizing the role parasite cycle knowledge, ultrasound and CT scan findings, sterilisation of the cyst and preventive measures to be taken to avoid spread of the disease. The authors also discuss the role of intra-operative cholangiogram as well as the various means of dealing with the residual pericystic cavity.Keywords: Hydatid cyst, Liver. Ecchinococcosis, Surgery, Abdominal pai

Global existence of solutions for the relativistic Boltzmann equation with arbitrarily large initial data on a Bianchi type I space-time

We prove, for the relativistic Boltzmann equation on a Bianchi type I space-time, a global existence and uniqueness theorem, for arbitrarily large initial data.Comment: 17 page