A copper laser using CuI vapor

A simple CuI double-pulsed laser was built. The dependence of power output on the delay between the two excitation pulses, temperature, and the type of buffer gas has been investigated. The laser pulse duration was measured.     

Buffer gas effect on ground and metastable populations in a pulsed CuBr laser

We have measured the time dependence of the concentration of copper atoms in the ground and metastable states in a pulsed CuBr laser by monitoring the absorption of the atomic copper lines 244.2 and 510.6 nm. In agreement with previous measurements in a CuCl laser, we found the populations to grow after the dissociation pulse, peaking many tens of microseconds later. Temperature and buffer gas species and pressure have a considerable influence on the details of the temporal evolution. The results are interpreted in terms of a schematic mechanism involving parallel dissociation processes. Qualitative agreement with the experimental results is quite good, but no attempt was made to elucidate the physical processes which actually occur during and after the dissociation pulse. In the course of the experiment the radiative transition probability of the 244.2 nm line was measured and found to be0.26 times 10^{-7}s^-1.     

Software monitoring with controllable overhead

We introduce the technique of software monitoring with controllable overhead (SMCO), which is based on a novel combination of supervisory control theory of discrete event systems and PID-control theory of discrete time systems. SMCO controls monitoring overhead by temporarily disabling monitoring of selected events for as short a time as possible under the constraint of a user-supplied target overhead o _t. This strategy is optimal in the sense that it allows SMCO to monitor as many events as possible, within the confines of o _t. SMCO is a general monitoring technique that can be applied to any system interface or API. We have applied SMCO to a variety of monitoring problems, including two highlighted in this paper: integer range analysis, which determines upper and lower bounds on integer variable values; and non-accessed period detection, which detects stale or underutilized memory allocations. We benchmarked SMCO extensively, using both CPU- and I/O-intensive workloads, which often exhibited highly bursty behavior. We demonstrate that SMCO successfully controls overhead across a wide range of target overhead levels; its accuracy monotonically increases with the target overhead; and it can be configured to distribute monitoring overhead fairly across multiple instrumentation points.     

Improving the multicommodity flow rates with network codes for two sources

In this work we introduce a construction and analysis of network codes for two sources. The region of achievable rates for this problem is still unknown. The scheme we suggest is based on modifying the multicommodity flow solution and thus improving the achievable rate region, w.r.t the uncoded case. The similarity to the flow problem allows our method to be implemented distributively. We show how the construction algorithm can be combined with distributed backpressure routing algorithms for wireless ad-hoc networks. For both the nondistributed case and the distributed case, the computational complexity of our algorithm for network coding is comparable to that of the parallel multicommodity flow problem. We provide non trivial upper and lower bounds on the performance of our scheme, using random coding techniques.     

Direct demodulation of Hartmann-Shack patterns

Hartmann-Shack wave-front sensors produce a distorted grid of spots whose deviation from perfection is linear with the wave-front gradient. Usually, the centroid of each spot is calculated to provide that deviation, but it is also possible to perform the calculation by Fourier demodulation of the spot pattern [Opt. Commun. 215, 285, 2003]. We show that this demodulation can be performed directly on the grid, without reverting to Fourier transforms. Tracking the motion of each centroid individually is limited to well-defined spots with motions smaller than their pitch. In contrast, our method treats the image as a whole, is not limited to non-overlapping or sharp spots, and allows large spot motions. By replicating the array of spots slightly beyond the edge of the aperture, we reduce the chance for boundary phase dislocations in the reconstruction of the wave front. The method is especially suited to very large arrays.     

Modeling of synchronized bursting events: the importance on inhomogeneity

Cultured in vitro neuronal networks are known to exhibit synchronized bursting events (SBE), during which most of the neurons in the system spike within a time window of approximately 100 msec. Such phenomena can be obtained in model networks based on Markram-Tsodyks frequency-dependent synapses. In order to account correctly for the detailed behavior of SBEs, several modifications have to be implemented in such models. Random input currents have to be introduced to account for the rising profile of SBEs. Dynamic thresholds and inhomogeneity in the distribution of neuronal resistances enable us to describe the profile of activity within the SBE and the heavy-tailed distributions of interspike intervals and interevent intervals. Thus, we can account for the interesting appearance of Levy distributions in the data.     

Polarization Talbot self-imaging with computer-generated,space-variant subwavelength dielectric gratings

Self-imaging of a periodic space-variant polarized field is demonstrated. The field is created by use of space-variant subwavelength dielectric gratings. Our observations include self-imaging of the fields at the Talbot planes as well as the translation of incident polarization variation into intensity modulation at certain planes. We demonstrate the formation of a one-dimensional nondiffracting beam with uniform intensity and a nontrivial polarization structure.     

Are measures of self-esteem, neuroticism, locus of control, and generalized self-efficacy indicators of a common core construct?

The authors present results of 4 studies that seek to determine the discriminant and incremental validity of the 3 most widely studied traits in psychology--self-esteem, neuroticism, and locus of control--along with a 4th, closely related trait--generalized self-efficacy. Meta-analytic results indicated that measures of the 4 traits were strongly related. Results also demonstrated that a single factor explained the relationships among measures of the 4 traits. The trait measures display relatively poor discriminant validity, and each accounted for little incremental variance in predicting external criteria relative to the higher order construct. In light of these results, the authors suggest that measures purporting to assess self-esteem, locus of control, neuroticism, and generalized self-efficacy may be markers of the same higher order concept. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Public Housing as Control: Spatial Policy of Settling Immigrants in Israeli Development Towns

This paper examines the relationship between inter-ethnic power relations and public housing policy for immigrants in Israel since 1948. Based on a comparative analysis of Israeli policy of housing Mizrahi immigrants in the 1950s and Russian immigrants in the 1990s, the paper argues that despite the perceived decline in the state's capacity, the implication of public housing policy has remained unchanged since the 1950s. By moving Jewish immigrants into development towns in sparsely populated and overwhelmingly Palestinian regions of the country, Israeli policy has served to Judaize these regions and to reinforce ethnic stratification among the country's Jewish population. In this manner, Israeli public housing policy was neither consistent with conceptions of post-Second World War public housing policies in welfare states nor with the recent impact of globalization and the free-market dynamics on public housing policies.