The cell wall sensor Wsc1p is involved in reorganization of actin cytoskeleton in response to hypo-osmotic shock in Saccharomyces cerevisiae

The cell wall is essential to preserve osmotic integrity of yeast cells. Some phenotypic traits of cell wall mutants suggest that, as a result of a weakening of the cell wall, hypo-osmotic stress-like conditions are created. Consequent expansion of the cell wall and stretching of the plasma membrane trigger a complex response to prevent cell lysis. In this work we examined two conditions that generate a cell wall and membrane stress: one is represented by the cell wall mutant gas1Delta and the other by a hypo-osmotic shock. We examined the actin cytoskeleton and the role of the cell wall sensors Wsc1p and Mid2p in these stress conditions. In the gas1 null mutant cells, which lack a beta(1,3)-glucanosyltransferase activity required for cell wall assembly, a constitutive marked depolarization of actin cytoskeleton was found. In a hypo-osmotic shock wild-type cells showed a transient depolarization of actin cytoskeleton. The percentage of depolarized cells was maximal at 30 min after the shift and then progressively decreased until cells reached a new steady-state condition. The maximal response was proportional to the magnitude of the difference in the external osmolarity before and after the shift within a given range of osmolarities. Loss of Wsc1p specifically delayed the repolarization of the actin cytoskeleton, whereas Wsc1p and Mid2p were essential for the maintenance of cell integrity in gas1Delta cells. The control of actin cytoskeleton is an important element in the context of the compensatory response to cell wall weakening. Wsc1p appears to be an important regulator of the actin network rearrangements in conditions of cell wall expansion and membrane stretching.     

Layer-oriented simulation tool

The Layer-Oriented Simulation Tool (LOST) is a numerical simulation code developed for analysis of the performance of multiconjugate adaptive optics modules following a layer-oriented approach. The LOST code computes the atmospheric layers in terms of phase screens and then propagates the phase delays introduced in the natural guide stars' wave fronts by using geometrical optics approximations. These wave fronts are combined in an optical or numerical way, including the effects of wave-front sensors on measurements in terms of phase noise. The LOST code is described, and two applications to layer-oriented modules are briefly presented. We have focus on the Multiconjugate adaptive optics demonstrator to be mounted upon the Very Large Telescope and on the Near-IR-Visible Adaptive Interferometer for Astronomy (NIRVANA) interferometric system to be installed on the combined focus of the Large Binocular Telescope.     

Using degradation data to assess reliability: a case study on train wheel degradation

Degradation experiments are usually used to assess the lifetime distribution of highly reliable products, which are not likely to fail under the traditional life tests or accelerated life tests. In such cases, if there exist product characteristics whose degradation over time can be related to reliability, then collecting ‘degradation data’ can provide information about product reliability. In general, the degradation data are modeled by a nonlinear regression model with random coefficients. If we can obtain the estimates of parameters under the model, then the failure‐time distribution can be estimated. In order to estimate those parameters, three basic methods are available, namely, the analytical, numerical and the approximate. They are chosen according to the complexity of the degradation path model used in the analysis. In this paper, the numerical and the approximate methods are compared in a simulation study, assuming a simple linear degradation path model. A comparison with traditional failure‐time analysis is also performed. The mean‐squared error of the estimated 100pth percentile of the lifetime distribution is evaluated for each one of the approaches. The approaches are applied to a real degradation data set. Copyright © 2008 John Wiley & Sons, Ltd.     

Construction and programming of an autonomous focus stacker

Focus stacking is a technique of photomacrography and photomicrography that produces images of small three-dimensional subjects with an arbitrarily high depth of field, unencumbered by diffraction, by combining the in-focus portions of a stack of images of the subject recorded at different focal planes. Software packages are available for postprocessing an image stack into the final image, but the stack images are normally shot either with (typically expensive) automated equipment or by a manual, time-consuming, and error-prone procedures. This paper discusses the construction of an autonomous stacker with inexpensive preassembled electronics and a moderate amount of mechanical construction, and its C++ software.     

Maximum density of quantum information in a scalable CMOS implementation of the hybrid qubit architecture

Scalability from single-qubit operations to multi-qubit circuits for quantum information processing requires architecture-specific implementations. Semiconductor hybrid qubit architecture is a suitable candidate to realize large-scale quantum information processing, as it combines a universal set of logic gates with fast and all-electrical manipulation of qubits. We propose an implementation of hybrid qubits, based on Si metal-oxide-semiconductor (MOS) quantum dots, compatible with the CMOS industrial technological standards. We discuss the realization of multi-qubit circuits capable of fault-tolerant computation and quantum error correction, by evaluating the time and space resources needed for their implementation. As a result, the maximum density of quantum information is extracted from a circuit including eight logical qubits encoded by the [[7, 1, 3]] Steane code. The corresponding surface density of logical qubits is 2.6 Mqubit/cm\(^2\).     

A VLSI structure forX(modm) operation

High-computing speed and modularity have made RNS-based arithmetic processors attractive for a long time, especially in signal processing, where additions and multiplications are very frequent. The VLSI technology renewed this interest because RNS-based circuits are becoming more feasible; however, intermodular operations degradate their performance and a great effort results on this topic. In this paper, we deal with the problem of performing the basic operationX(modm), that is the remainder of the integer divisionX/m, for large values of the integerX, following an approximating and correcting approach, which guarantees the correctness of the result. We also define a structure to computeX(modm) by means of few fast VLSI binary multipliers, which is exemplified for 32-bit long numbers, obtaining a total response time lower than 200 nsec. Furthermore, such a structure is evaluated in terms of VLSI complexity and area and time figuresA=?(n ² T _m ² ) andT=?(T _M ) for the parameterT _M in \([\log n,\sqrt n ]\) are derived. A simple positional-to-residue converter is finally presented, based on this structure; it improves some complexity results previously obtained by authors.     

Onion under Microscope: An in-depth analysis of the Tor Web

World Wide Web - Tor is an open source software that allows accessing various kinds of resources, known as hidden services, while guaranteeing sender and receiver anonymity. Tor relies on a free,...