Investment and credit constraints in transition economies : micro evidence from Poland, the Chrch Republic, Bulgaria and Romania.

In this paper we investigate to what extent firm investment in transition countries is sensitive to internal finance. We use accounts data of over 4000 companies in four countries at different stages of transition. We find that firms in Bulgaria and Romania are less sensitive to internal financing constraints, in contrast to firms in Poland and the Czech Republic. A likely explanation is that Bulgaria and Romania, which are the least advanced in the reforms towards market economy, have a stronger persistence of soft budget constraints than in the other two more advanced countries.Investment; Trade; Credit; Economy; Companies;

The effect of ownership and competitive pressure on firm performance in transition countries. Micro evidence from Bulgaria, Romania and Poland.

Country; Firm performance; Ownership; Performance;

Nanotesla torque magnetometry using a microcantilever

We present a novel ultrasensitive magnetometry technique using a micromachined magnetic antilever that is brought in resonance. The induced magnetic moment generates a torque on the cantilever, thereby effectively stiffening the cantilever spring constant and changing its resonance frequency. Experiments are in good correspondence with the presented analytical model for this frequency shift, predicting the detection of nanotesla magnetic fields.\u

Perturbative expansions from Monte Carlo simulations at weak coupling: Wilson loops and the static-quark self-energy

Perturbative coefficients for Wilson loops and the static-quark self-energy are extracted from Monte Carlo simulations at weak coupling. The lattice volumes and couplings are chosen to ensure that the lattice momenta are all perturbative. Twisted boundary conditions are used to eliminate the effects of lattice zero modes and to suppress nonperturbative finite-volume effects due to Z(3) phases. Simulations of the Wilson gluon action are done with both periodic and twisted boundary conditions, and over a wide range of lattice volumes (from $3^4$ to $16^4$) and couplings (from $\beta \approx 9$ to $\beta \approx 60$). A high precision comparison is made between the simulation data and results from finite-volume lattice perturbation theory. The Monte Carlo results are shown to be in excellent agreement with perturbation theory through second order. New results for third-order coefficients for a number of Wilson loops and the static-quark self-energy are reported.Comment: 36 pages, 15 figures, REVTEX documen

New Procedure for the Isolation of Membrane Vesicles of Bacillus subtilis and an Electron Microscopy Study of Their Ultrastructure

A rapid procedure for the isolation of membrane vesicles of Bacillus subtilis is described that minimizes the action of proteolytic enzymes, excreted by this organism, on the membrane proteins. The membrane vesicles obtained have, in addition to a low endogenous respiration rate, a low endogenous activity for transport of amino acids and carboxylic acids. In the presence of the electron donor, ascorbate-phenazine methosulfate, the transport activities for these compounds were comparable to the activities of intact cells. In addition, these activities were retained for a prolonged period of time. Electron microscopy examination of thin sections of the vesicles showed that the preparation consisted almost exclusively of membrane vesicles which were not contaminated with other cell components. The membrane vesicles, which are six to seven times smaller in diameter than protoplasts, often enclosed smaller vesicles. Freeze-etching of intact cells, protoplasts, and membrane vesicles showed that the orientation of the membrane of the vesicles was identical to the orientation of the plasma membrane in intact cells and protoplasts. This also held for the majority of the membranes of the enclosed vesicles, only 15% having the opposite orientation

Harnessing open-source technology for low-cost automation in synthesis: flow chemical deprotection of silyl ethers using a homemade autosampling system.

An inexpensive homemade 3-axis autosampler was used to facilitate the automation of an acid catalysed flow chemical desilylation reaction. Harnessing open-source software technologies (Python, OpenCV), an automated computer-vision controlled liquid-liquid extraction step was used to provide effective inline purification. A Raspberry Pi single-board computer was employed to interface with the motors used in the autosampler and actuated fluidic valves

Probing the Light Pseudoscalar Window

Very light pseudoscalars can arise from the symmetry-breaking sector in many extensions of the Standard Model. If their mass is below 200 MeV, they can be long-lived and have interesting phenomenology. We discuss the experimental constraints on several models with light pseudoscalars, including one in which the pseudoscalar is naturally fermiophobic. Taking into account the stringent bounds from rare K and B decays, we find allowed parameter space in each model that may be accessible in direct production experiments. In particular, we study the photoproduction of light pseudoscalars at Jefferson Lab and conclude that a beam dump experiment could explore some of the allowed parameter space of these models.Comment: 22 pages, 4 figure

The effects of dispersion on time-of-flight acoustic velocity measurements in a wooden rod.

The stiffness of wood can be estimated from the acoustic velocity in the longitudinal direction. Studies have reported that stiffness measurements obtained using time-of-flight acoustic velocity measurements are overestimated compared to those obtained using the acoustic resonance and bending test methods. More research is needed to understand what is causing this phenomenon. In this work, amplitude threshold time-of-flight, resonance, and guided wave measurements are performed on wooden and aluminium rods. Using guided wave theory, it is shown through simulations and experimental results that dispersion causes an overestimation of time-of-flight measurements. This overestimation was able to be mitigated using dispersion compensation. However, other guided wave techniques could potentially be used to obtain improved measurements.Published onlin