Versatile wideband balanced detector for quantum optical homodyne tomography

We present a comprehensive theory and an easy to follow method for the design and construction of a wideband homodyne detector for time-domain quantum measurements. We show how one can evaluate the performance of a detector in a specific time-domain experiment based on the electronic spectral characteristic of that detector. We then present and characterize a high-performance detector constructed using inexpensive, commercially available components such as low-noise high-speed operational amplifiers and high-bandwidth photodiodes. Our detector shows linear behavior up to a level of over 13 dB clearance between shot noise and electronic noise, in the range from DC to 100 MHz. The detector can be used for measuring quantum optical field quadratures both in the continuous-wave and pulsed regimes with standard commercial mode-locked lasers.     

Application of the multireference equation of motion coupled cluster method,including spin–orbit coupling,to the atomic spectra of Cr,Mn, Fe and Co

The recently introduced multireference equation of motion (MR-EOM) approach is combined with a simple treatment of spin–orbit coupling, as implemented in the ORCA program. The resulting multireference equation of motion spin–orbit coupling (MR-EOM-SOC) approach is applied to the first-row transition metal atoms Cr, Mn, Fe and Co, for which experimental data are readily available. Using the MR-EOM-SOC approach, the splittings in each L-S multiplet can be accurately assessed (root mean square (RMS) errors of about 70 cm^?1). The RMS errors for J-specific excitation energies range from 414 to 783 cm^?1 and are comparable to previously reported J-averaged MR-EOM results using the ACESII program. The MR-EOM approach is highly efficient. A typical MR-EOM calculation of a full spin–orbit spectrum takes about 2 CPU hours on a single processor of a 12-core node, consisting of Intel XEON 2.93 GHz CPUs with 12.3 MB of shared cache memory.     

Polyphenolics with Strong Antioxidant Activity from Acacia nilotica Ameliorate Some Biochemical Signs of Arsenic-Induced Neurotoxicity and Oxidative Stress in Mice

Neurotoxicity is a serious health problem of patients chronically exposed to arsenic. There is no specific treatment of this problem. Oxidative stress has been implicated in the pathological process of neurotoxicity. Polyphenolics have proven antioxidant activity, thereby offering protection against oxidative stress. In this study, we have isolated the polyphenolics from Acacia nilotica and investigated its effect against arsenic-induced neurotoxicity and oxidative stress in mice. Acacia nilotica polyphenolics prepared from column chromatography of the crude methanol extract using diaion resin contained a phenolic content of 452.185 ± 7.879 mg gallic acid equivalent/gm of sample and flavonoid content of 200.075 ± 0.755 mg catechin equivalent/gm of sample. The polyphenolics exhibited potent antioxidant activity with respect to free radical scavenging ability, total antioxidant activity and inhibition of lipid peroxidation. Administration of arsenic in mice showed a reduction of acetylcholinesterase activity in the brain which was counteracted by Acacia nilotica polyphenolics. Similarly, elevation of lipid peroxidation and depletion of glutathione in the brain of mice was effectively restored to normal level by Acacia nilotica polyphenolics. Gallic acid methyl ester, catechin and catechin-7-gallate were identified in the polyphenolics as the major active compounds. These results suggest that Acacia nilotica polyphenolics due to its strong antioxidant potential might be effective in the management of arsenic induced neurotoxicity.     

Distribution of the minimum number of points in a scanning interval on the line

Let N points be distributed at random on [0,1), and let y(t) be the number of points in [t,t+p), when p? (0,1). For certain step functions, g(t), for all t in [0,1 ? p) is found. Choosing g(t)≡m results in a multiple comparison test, which may be used to test for differences between any m independent normally distributed means at a given experiment-wide level of significance.     

Die Anwendung der Absorptionsspectralanalyse

Ohne Zusammenfassung     

Multi-element analysis of bone from the osteogenesis imperfecta model (OIM) mouse using thermal and fast neutron activation analysis

Osteogenesis imperfecta (OI) is a heritable osteoporotic bone disease, due to defects in either type I procollagen genes (COL1A1 or COL1A2), resulting in abnormal and/or reduced levels of type I procollagen and alterations in bone mineralization. Our long term objectives are to evaluate the impact of proα1(I) and proα2(I) collagen mutations and the role of the genetic background on bone mineralization. Tibias from wildtype, heterozygous (oim/+), and homozygous (oim/oim) animals were subjected to instrumental neutron activation analysis (INAA) to measure F, P, Na, Mg, Cl, Ca, K, and Zn using the University of Missouri Research Reactor (MURR) pneumatic-tube irradiation facility.     

Ultrasonic detection of the pinning of dislocations by point defects in lead—II. Model for dislocation defect interaction

Experiments are presented to establish that irradiation produced defects in lead not only pin dislocations but also can be trapped at the ends of dislocation lines in agreement with the model proposed by Thompson, Buck, Huntington and Barnes. This model indicates that there is a temperature T^* at which there is a maximum pinning of dislocations. T^* is found to be near 140 K. The data of Part I are analyzed according to this model using reasonable values of the dislocation density and the binding energy of the defect in the trap. The resulting activation energy for the region A process in the reaction kinetics model is found to be 0.15 eV which is consistent with the value found from an eigenvalue expansion model.     

A study of electromigration of nickel in lead

The steady state method was used to study the electromigration of ⁶³Ni in Pb. For the temperature range 180–290°C, and Ni concentration range 0.1–1000 ppm, Ni migrates toward the anode. For dilute samples (0.1 ppm Ni) the effective charge varies linearly with the inverse resistivity from ?6.75 at 188°C to ?4.97 at 289°C. The 1/ρ dependence is given by $\text{Z1 = (1.4 ± 0.3)?(288 ± 13)× 10}{}^{\mathrm{?6}}\text{/ρ}$. The effective charge is a function of the Ni concentration, increasing in magnitude with increasing concentration. For 1000 ppm Ni, |Z1| exhibits a sharp maximum around 260°C; below 230°C electromigration takes place at a much slower rate, probably due to precipitation.     

Electromigration of copper in lead

The electromigration of copper in lead was measured under isothermal conditions by a steady-state method. ⁶⁴Cu was introduced into the lead solvent as a radioactive tracer solute. After electromigration, the steady-state, concentration-distance curve was determined by standard sectioning, weighing and counting techniques. Although the experiments extend from 215 to 303°C, the measurements for Z¹, the effective charge number for copper in lead, appear to show at low temperature a strong dependence on concentration and are also difficult to reproduce satisfactorily in this temperature range. Accordingly only the results in the range from 240°C and up have been included in calculating the electromigration parameters. These results give Z¹ in the range 1.1 ± 0.3 and indicate an electrostatic charge, Z_el, of 1,8 ±0.9.     

Noiseless independent signal and power amplification

We present a noiseless optical amplifier comprising a signal-amplifying feed-forward loop and a power-amplifying injection-locked laser. We demonstrate that the signal amplifier can attain a signal-transfer coefficient limited solely by the quantum efficiency of our in-loop photodetector and that we can independently amplify the optical power while leaving the normalized intensity-noise spectral density of the input field unchanged.