8,291 research outputs found

    Dissecting the Workforce and Workplace for Clinical Endocrinology, and the Work of Endocrinologists Early in Their Careers

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    [Excerpt] No national mechanism is in place for an informed, penetrating, and systematic assessment of the physician workforce such as that achieved by the National Science Foundation (NSF) for the periodic evaluation of the nation’s scientists and engineers. Likewise, knowledge of the workforce for clinical research is enigmatic and fragmentary despite the serial recommendations of “blue-ribbon” panels to establish a protocol for the recurrent assessment of clinical investigators early in their careers. Failure to adopt a national system for producing timely, high-quality data on the professional activities of physicians limits the application of improvement tools for advancing clinical investigation and ultimately improving clinical practice. The present study was designed as a pilot project to test the feasibility of using Web-based surveys to estimate the administrative, clinical, didactic, and research work of subspecialty physicians employed in academic, clinical, federal, and pharmaceutical workplaces. Physician members of The Endocrine Society (TES) were used as surrogate prototypes of a subspecialty workforce because of their manageable number and investigative tradition. The results establish that Web-based surveys provide a tool to assess the activities of a decentralized workforce employed in disparate workplaces and underscore the value of focusing on physician work within the context of particular workplaces within a subspecialty. Our report also provides a new and timely snapshot of the amount and types of research performed by clinically trained endocrinologists and offers an evidenced-based framework for improving the investigative workforce in this medical subspecialty

    Reliable solid-state circuits Semiannual report no. 2, Jun. 1 - Nov. 30, 1965

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    Pulse width modulator and other microminiaturized electronic equipment for space age application

    On the resistivity at low temperatures in electron-doped cuprate superconductors

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    We measured the magnetoresistance as a function of temperature down to 20mK and magnetic field for a set of underdoped PrCeCuO (x=0.12) thin films with controlled oxygen content. This allows us to access the edge of the superconducting dome on the underdoped side. The sheet resistance increases with increasing oxygen content whereas the superconducting transition temperature is steadily decreasing down to zero. Upon applying various magnetic fields to suppress superconductivity we found that the sheet resistance increases when the temperature is lowered. It saturates at very low temperatures. These results, along with the magnetoresistance, cannot be described in the context of zero temperature two dimensional superconductor-to-insulator transition nor as a simple Kondo effect due to scattering off spins in the copper-oxide planes. We conjecture that due to the proximity to an antiferromagnetic phase magnetic droplets are induced. This results in negative magnetoresistance and in an upturn in the resistivity.Comment: Accepted in Phys. Rev.

    Charged Rotating Black Holes in Equilibrium

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    Axially symmetric, stationary solutions of the Einstein-Maxwell equations with disconnected event horizon are studied by developing a method of explicit integration of the corresponding boundary-value problem. This problem is reduced to non-leaner system of algebraic equations which gives relations between the masses, the angular momenta, the angular velocities, the charges, the distance parameters, the values of the electromagnetic field potential at the horizon and at the symmetry axis. A found solution of this system for the case of two charged non-rotating black holes shows that in general the total mass depends on the distance between black holes. Two-Killing reduction procedure of the Einstein-Maxwell equations is also discussed.Comment: LaTeX 2.09, no figures, 15 pages, v2, references added, introduction section slightly modified; v3, grammar errors correcte

    Origin of the anomalous Hall Effect in overdoped n-type cuprates: current vertex corrections due to antiferromagnetic fluctuations

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    The anomalous magneto-transport properties in electron doped (n-type) cuprates were investigated using Hall measurements at THz frequencies. The complex Hall angle was measured in overdoped Pr2x_{\rm 2-x}Cex_{\rm x}CuO4_{\rm 4} samples (x=0.17 and 0.18) as a continuous function of temperature above TcT_c at excitation energies 5.24 and 10.5 meV. The results, extrapolated to low temperatures, show that inelastic scattering introduces electron-like contributions to the Hall response. First principle calculations of the Hall angle that include current vertex corrections (CVC) induced by electron interactions mediated by magnetic fluctuations in the Hall conductivity reproduce the temperature, frequency, and doping dependence of the experimental data. These results show that CVC effects are the source of the anomalous Hall transport properties in overdoped n-\text{-}type cuprates.Comment: 5 pages, 3 figure

    Electromagnetic modeling and optimization of packaged photodetector modules for 100 Gbit/s applications

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    In this paper, we propose an accurate full 3D EM behavioral model of PD chips for the first time. The model, which is meshed at 130 GHz, runs for about 17 minutes on an Intel Core2 Duo CPU@3 GHz PC with 3.5 GB of RAM. The impact of various parameters in wire- bonding transitions for transmission characteristic is summarized in the Table I. When numbers of bonding wires are placed separately all through strips of CBCPWs as well as keeping an optimized gap of transitions, more than 10 GHz bandwidth improvement can be achieved compared the worst case. We also notice that optimization on bonding wires does not significantly improve the fast decay beyond 60 GHz. Further investigation and optimization of the transition is required including a redesign of the CBCPW

    'Return to equilibrium' for weakly coupled quantum systems: a simple polymer expansion

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    Recently, several authors studied small quantum systems weakly coupled to free boson or fermion fields at positive temperature. All the approaches we are aware of employ complex deformations of Liouvillians or Mourre theory (the infinitesimal version of the former). We present an approach based on polymer expansions of statistical mechanics. Despite the fact that our approach is elementary, our results are slightly sharper than those contained in the literature up to now. We show that, whenever the small quantum system is known to admit a Markov approximation (Pauli master equation \emph{aka} Lindblad equation) in the weak coupling limit, and the Markov approximation is exponentially mixing, then the weakly coupled system approaches a unique invariant state that is perturbatively close to its Markov approximation.Comment: 23 pages, v2-->v3: Revised version: The explanatory section 1.7 has changed and Section 3.2 has been made more explici
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