3,005 research outputs found
A phenomenological study of African American GS-13 to GS-15 managers within the federal government
No full textAfrican Americans are underrepresented in senior leadership positions of the Federal Government. As of 2009, African Americans occupied less than seven percent of senior pay level positions (EOEC, 2009). Kohli, Gans, and Hairston (2011) projected that African American representation in senior leadership positions will remain stagnant over the next decade. Thirteen GS-13 to GS-15 federal government managers participated in this qualitative phenomenological study. Semi-structured interviews were conducted to explore the lived experiences of federal government managers. Moustakas’ modified van Kaam method and NVivo10 software was used to analyze transcribed participant interviews. The results from the study indicate the need for mentoring relationships and agency-sponsored training programs to prepare African Americans for senior leadership positions. Based on lived experiences, participants indicated that effective communication was essential for obtaining and sustaining senior leadership positions. Findings from the study also indicate that mobility is a major concern for African Americans who aspire to achieve senior leadership status. Federal government leaders in general schedule leadership positions are the major hiring candidate pool for senior leadership positions (EOEC, 2009). Information from this study may assist African Americans in advancing to federal senior leadership positions
EBUS-GS and VBN for GGO lesions
No full textBackground: Endobronchial ultrasonography with guide sheath (EBUS-GS) could be useful for diagnosing ground-glass opacity (GGO) predominant-type lesions in the peripheral lung. Furthermore, several studies have reported that transbronchial biopsy using EBUS-GS and virtual bronchoscopic navigation (VBN) was safe and effective for diagnosing small peripheral lung lesions. Our objectives were to diagnose solitary peripheral GGO predominant-type lesions by transbronchial biopsy using EBUS-GS and VBN under radiographic fluoroscopic guidance, and to evaluate the clinical factors associated with diagnostic yield. Methods: The medical records of 169 patients with GGO predominant-type lesions who underwent transbronchial biopsy using EBUS-GS and VBN under radiographic fluoroscopic guidance were retrospectively reviewed. Results: Endobronchial ultrasonography images could be obtained for 156 (92%) of 169 GGO predominant-type lesions, and 116 (69%) were successfully diagnosed by this method (20 of 31 pure GGO lesions [65%]; 96 of 138 mixed GGO predominant-type lesions [70%]). The mean size of diagnosed lesions was significantly larger than that of nondiagnosed lesions (22 mm versus 18 mm, p < 0.01). Regarding diagnostic yield based on computed tomography sign, cases with presence of a bronchus leading directly to a lesion had significantly higher diagnostic yield than the other lesions (p < 0.01). Conclusions: The addition of VBN to EBUS-GS could be useful in clinical practice for diagnosing GGO predominant-type lesions in the peripheral lung
Measuring the joint spectral mode of photon pairs using intensity interferometry
No full textThe ability to manipulate and measure the time-frequency structure of quantum light is useful for information processing and metrology. Measuring this structure is also important when developing quantum light sources with high modal purity that can interfere with other independent sources. Here, we present and experimentally demonstrate a scheme based on intensity interferometry to measure the joint spectral mode of photon pairs produced by spontaneous parametric down-conversion. We observe correlations in the spectral phase of the photons due to chirp in the pump. We show that our scheme can be combined with stimulated emission tomography to quickly measure their mode using bright classical light. Our scheme does not require phase stability, nonlinearities, or spectral shaping and thus is an experimentally simple way of measuring the modal structure of quantum light
Assessing suicidal risk with antiepileptic drugs
No full textMarco Mula2, Gail S Bell1, Josemir W Sander1,31Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, and National Hospital for Neurology and Neurosurgery, UCL Hospitals NHS Foundation Trust, London, United Kingdom; 2Department of Clinical and Experimental Medicine, Division of Neurology, Amedeo Avogadro University, University Hospital Maggiore della Carit&agrave;, Novara, Italy; 3SEIN &ndash; Epilepsy Institute in the Netherlands Foundation, Heemstede, The NetherlandsAbstract: Recently, the US Food and Drug Administration issued an alert about an increased risk for suicidality during treatment with antiepileptic drugs (AEDs) for different indications, including epilepsy. We discuss the issue of suicide in epilepsy with special attention to AEDs and the assessment of suicide in people with epilepsy. It has been suggested that early medical treatment with AEDs might potentially reduce suicide risk of people with epilepsy, but it is of great importance that the choice of drug is tailored to the mental state of the patient. The issue of suicidality in epilepsy is likely to represent an example of how the underdiagnosis of psychiatric symptoms, the lack of input from professionals (eg, psychologists, social workers, and psychiatrists), and the delay in an optimized AED therapy may worsen the prognosis of the condition with the occurrence of severe complications such as suicide.Keywords: epilepsy, suicide, adverse effect, depressio
Rigorous results on the strongly correlated electron systems by the spin-reflection-positivity method
No full textIn this talk, we shall briefly review some results on the strongly correlated electron systems, derived recently by applying Lieb's spin-reflection-positivity method. To explain the basic ideas of this method to a wide audience, we emphasize the important role played by Marshall's rule in studying the many-body systems.Physics, AppliedPhysics, Condensed MatterPhysics, MathematicalSCI(E)CPCI-S(ISTP)
Antiferromagnetic correlation in the half-filled strongly correlated electron models at nonzero temperature: A rigorous result
No full textAs an extension of our previous rigorous investigation on the spin correlations in the ground states of the half-filled Hubbard model and the periodic Anderson model [G. S. Tian, Phys. Rev. B 50, 6246 (1994)], in the present paper we study the behavior of these correlation functions at finite temperature. We show rigorously that, at any T not equal0, the predominant spin correlations in these systems are antiferromagnetic. Furthermore, based on this result, we also show that a quasi-one (or two)-dimensional itinerant electron ferrimagnet must have a gapless branch of ferromagnetic excitations. This conclusion is consistent with the previous results derived by the spin-wave theory.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000169283000058&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, Condensed MatterSCI(E)10ARTICLE22null6
A 1-GS/s 6–8-b Cryo-CMOS SAR ADC for Quantum Computing
No full textThis article presents a two-times interleaved, loop-unrolled SAR analog-to-digital converter (ADC) operational from 300 down to 4.2 K. The 6-8-bit resolution and the sampling speed up to 1 GS/s are targeted at digitizing the multi-channel frequency-multiplexed input in a spin-qubit reflectometry readout for quantum computing. To optimize the circuit for the altered device behavior at cryogenic temperatures, a modified common-mode switching scheme is adopted as well as a flexible calibration. The design is implemented in 40-nm CMOS technology and achieves 36.2-dB signal to noise and distortion ratio (SNDR) for Nyquist input at 4.2 K while maintaining a Walden figure of merit (FOM textsubscript W) of 200 pJ/conv-step (for a 10.8-mW power consumption), including the clock receiver, and 15 pJ/conv-step (for a 0.8-mW power consumption) for just the core ADC. With these specifications, the ADC can support the simultaneous readout of 20 qubit channels with a power consumption of 0.5 mW/qubit, thus advancing toward the full integration of the cryogenic readout for future large-scale quantum processors.QCD/Sebastiano LabElectronicsQuantum Circuit Architectures and Technolog
Development of a numerical methodology for flowforming process simulation of complex geometry tubes
No full textPublisher Copyright: © 2017 Author(s).Nowadays, the incremental flowforming process is widely explored because of the usage of complex tubular products is increasing due to the light-weighting trend and the use of expensive materials. The enhanced mechanical properties of finished parts combined with the process efficiency in terms of raw material and energy consumption are the key factors for its competitiveness and sustainability, which is consistent with EU industry policy. As a promising technology, additional steps for extending the existing flowforming limits in the production of tubular products are required. The objective of the present research is to further expand the current state of the art regarding limitations on tube thickness and diameter, exploring the feasibility to flowform complex geometries as tubes of elevated thickness of up to 60 mm. In this study, the analysis of the backward flowforming process of 7075 aluminum tubular preform is carried out to define the optimum process parameters, machine requirements and tooling geometry as demonstration case. Numerical simulation studies on flowforming of thin walled tubular components have been considered to increase the knowledge of the technology. The calculation of the rotational movement of the mesh preform, the high ratio thickness/length and the thermomechanical condition increase significantly the computation time of the numerical simulation model. This means that efficient and reliable tools able to predict the forming loads and the quality of flowformed thick tubes are not available. This paper aims to overcome this situation by developing a simulation methodology based on FEM simulation code including new strategies. Material characterization has also been performed through tensile test to able to design the process. Finally, to check the reliability of the model, flowforming tests at industrial environment have been developed.Peer reviewe
Optimizing Support Vector Machines with ISBA-A-gs Land Surface Variables as a Surrogate Model to Simulate ASCAT Derived Parameters
No full textThe TU-Wien developed a soil moisture retrieval algorithm that uses the incidence angle dependence of backscatter to obtain soil moisture estimates (Wagner et al., 1999). The core of this algorithm is a second order Taylor expansion with which the backscatter is normalized at a reference angle. Studies have shown that the first and second order derivative within this Taylor expansion, known as slope and curvature, are somehow related to the wet biomass and structure of vegetation. The general approach to forward model satellite observations with land surface variables in a data assimilation framework is through a radiative transfer model (Albergel et al., 2017). However, this requires plenty of assumptions about the vegetation canopy (such as stem height, shape, size, orientation etc.) and is therefore relatively inefficient for understanding the impact of soil moisture and vegetation dynamics on backscatter on a large scale. This study investigates the possibility of using support vector machines as a surrogate model instead of a radiative transfer model to link the TU-Wien normalized backscatter and slope to land surface variables soil moisture and leaf area index. The land surface variables are simulations from the CO2-responsive ISBA-A-gs land surface model. Support vector machines have the advantage of providing implicit kernel functions, which make them very useful for non-linear problems. The ISBA-A-gs data is provided by Météo-France. In total, 1324 support vector machines have been optimized through a cross validated grid search. The optimized hyperparameters were shown to have spatial consistency and look promising as an initial approach to forward modelling backscatter and slope. The SVM performances are further investigated through corresponding land cover types of grid points and the land surface variables.Geoscience and Remote Sensin
Single-shot discrimination of coherent states beyond the standard quantum limit
No full textThe discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted coherent states at a telecom wavelength. Owing to its dynamic range and high efficiency, we achieve a bit error probability that unconditionally exceeds the standard quantum limit (SQL) by up to 7.7 dB. The improvement to the SQL persists for signals containing up to approximately seven photons on average and is achieved in a single shot (i.e., without measurement feedback), thus making our approach compatible with larger bandwidths.No Full Tex
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