Factors influencing convergence of a learning system

Measurement rays affecting algorithm for learning control syste

Director Reputation, Ceo-Board Power, And The Dynamics Of Board Interlocks

This study advances research on CEO-board relationships, interlocking directorates, and director reputation by examining how contests for intraorganizational power can affect interorganizational ties. We propose that powerful top managers seek to maintain their control by selecting and retaining board members with experience on other, passive boards and excluding individuals with experience on more active boards. We also propose that powerful boards similarly seek to maintain their control by favoring directors with a reputation for more actively monitoring management and avoiding directors with experience on passive boards. Hypotheses are tested longitudinally using CEO-board data taken from 491 of the largest U.S. corporations over a recent seven-year period. The findings suggest that variation in CEO-board power relationships across organizations has contributed to a segmentation of the corporate director network. We discuss how our perspective can reconcile contrary views and debates on whether increased board control has diffused across large U.S. corporations.(.)Managemen

Defections From The Inner Circle: Social Exchange, Reciprocity, And The Diffusion Of Board Independence In Us Corporations

This study seeks to reconcile traditional sociological views of the corporate board as an instrument of elite cohesion with recent evidence of greater board activism and control over top management. We propose that CEO-directors may typically support fellow CEOs by impeding increased board control over management but that CEO-directors may also foster this change if they have experienced it in their own corporation. Drawing on social exchange theory, we develop and test the argument that these CEO-directors may experience a reversal in the basis for generalized social exchange with other top managers from one of deference and support to one of independence and control. Using data from a large sample of major U.S. corporations over a recent ten-year period, we show (1) how CEO-directors ''defect'' from the network of mutually supportive corporate leaders, (2) how defections have diffused across organizations and over time, and (3) how this has contributed to increased board control, as measured by changes in board structure, diversification strategy, and contingent compensation. We also provide evidence that a social exchange perspective can explain the diffusion of these changes better than more conventional perspectives on network diffusion that emphasize imitation or learning.Business Administratio

Making difficult health decisions: a motivated decision processing model

This study introduces and evaluates a model of motivated health decision processing. In this model, threatening health decision information is thought to lead to two potentially incompatible motivations in decision makers: the desire to process information in an effortful manner, and the desire to defend against threat. The model proposes that these dual motivations lead to biased but effortful processing of decision options. The model was tested empirically by experimentally manipulating exposure to threatening information and measuring decision information processing and decision strategy selection. Participants (N = 100; age 40+) were randomly assigned to one of two groups and exposed to either threatening or non-threatening information about skin cancer. They were asked to read about and choose from five skin cancer treatments; a computerized process-tracing tool recorded their pattern of information acquisition as they perused the information. Results showed that compared to participants in the low threat condition, participants in the high threat condition were more likely to avoid information about death and to use an attribute-based decision strategy. Participants in the high threat condition and participants who used an attribute-based decision strategy were also more likely to make an accurate decision. Post hoc analyses showed that participants in the high threat condition were more likely than participants in the low threat condition to use an effective lexicographic decision strategy, and that anxiety and impulsivity moderated the relationship between condition and decision strategy. The results of this study suggest that exposure to perceived threats can lead to patients' avoidance of frightening, but important, information about treatments and to the use of heuristic decision strategies while making treatment decisions

Scalable gate architecture for densely packed semiconductor spin qubits

We demonstrate a 12 quantum dot device fabricated on an undoped Si/SiGe heterostructure as a proof-of-concept for a scalable, linear gate architecture for semiconductor quantum dots. The device consists of 9 quantum dots in a linear array and 3 single quantum dot charge sensors. We show reproducible single quantum dot charging and orbital energies, with standard deviations less than 20% relative to the mean across the 9 dot array. The single quantum dot charge sensors have a charge sensitivity of 8.2 x 10^{-4} e/root(Hz) and allow the investigation of real-time charge dynamics. As a demonstration of the versatility of this device, we use single-shot readout to measure a spin relaxation time T1 = 170 ms at a magnetic field B = 1 T. By reconfiguring the device, we form two capacitively coupled double quantum dots and extract a mutual charging energy of 200 microeV, which indicates that 50 GHz two-qubit gate operation speeds are feasible

Increased plasma concentration of vascular endothelial growth factor in patients with atopic dermatitis and its relation to disease severity and platelet activation

BACKGROUND: Overproduction of vascular endothelial growth factor (VEGF) in atopic dermatitis (AD) lesions has previously been observed. It is also known that platelet is an important source of VEGF and platelet factor 4 (PF-4), a potential marker of AD severity. AIM: To evaluate concentrations of VEGF and its soluble receptors (sVEGF-R1 and sVEGF-R2) in the plasma of AD patients and to examine its possible correlation with disease severity and plasma concentrations of PF-4, a platelet activation marker. METHODS: Plasma concentrations of VEGF and its receptors and levels of PF-4 were measured by an immunoenzymatic assay in 51 AD patients and in 35 healthy non-atopic controls. The severity of the disease was evaluated using the eczema area and severity index. RESULTS: AD patients showed significantly increased VEGF and PF-4 plasma concentrations as compared with the controls. Plasma concentrations of sVEGF-R1 and sVEGF-R2 did not differ between the groups. There were no remarkable correlations between plasma VEGF concentration and disease severity or between VEGF and PF-4 concentration. CONCLUSIONS: This study shows that plasma concentration of VEGF may be increased in patients suffering from AD. It seems that plasma VEGF concentration is not a useful marker of disease severity and, apart from platelets, other cells might also release the cytokine

Screening nuclear field fluctuations in quantum dots for indistinguishable photon generation

A semiconductor quantum dot can generate highly coherent and indistinguishable single photons. However, intrinsic semiconductor dephasing mechanisms can reduce the visibility of two-photon interference. For an electron in a quantum dot, a fundamental dephasing process is the hyperfine interaction with the nuclear spin bath. Here we directly probe the consequence of the fluctuating nuclear spins on the elastic and inelastic scattered photon spectra from a resident electron in a single dot. We find the nuclear spin fluctuations lead to detuned Raman scattered photons which are distinguishable from both the elastic and incoherent components of the resonance fluorescence. This significantly reduces two-photon interference visibility. However, we demonstrate successful screening of the nuclear spin noise which enables the generation of coherent single photons that exhibit high visibility two-photon interference.Comment: 5 pages, 4 figures + Supplementary Informatio

Effect of Mn and Mg dopants on vacancy defect formation in ammonothermal GaN

We have applied positron annihilation spectroscopy to study the formation of Ga vacancy related defects in Mg and Mn doped bulk GaN crystals grown by the ammonothermal method. We show that Mn doping has little or no effect on the formation of Ga vacancies, while Mg doping strongly suppresses their formation, in spite of both dopants leading to highly resistive material. We suggest the differences are primarily due to the hydrogen-dopant interactions. Further investigations are called for to draw a detailed picture of the atomic scale phe-nomena in the synthesis of ammonothermal GaN.Peer reviewe

The Texture of Surficial Sediments in Western Long Island Sound off the Norwalk Islands, Connecticut

Grain-size analyses were performed on 69 samples from western Long Island Sound. The relative grain-size frequency distributions and related statistics are reported herein. Descriptions of the benthic character from video tapes and still camera photographs of the bottom at these stations, and 33 others, are also presented. The southern and eastern parts of the study area are dominated by poorly sorted clayey silts that have nearly symmetrical distributions. Gravelly sediments are prevalent in the shallow northwestern part of the study area, but are also present in central part of the study area. Bands of sand, silty sand, and sand-silt-clay occur on the flanks of the gravelly areas