Novel perturbation expansion for the Langevin equation

We discuss the randomly driven systemdx/dt= -W(x) +f(t), wheref(t) is a Gaussian random function or stirring force withf(t)f(t)=2(t–t), andW(x) is of the formgx ¹⁺². The parameter is a measure of the nonlinearity of the equation. We show how to obtain the correlation functionsx(t)f(t)···x(t( n)) _f as a power series in. We obtain three terms in the expansion and show how to use Padé approximants to analytically continue the answer in the variable. By using scaling relations, we show how to get a uniform approximation to the equal-time correlation functions valid for allg and.     

Determining theCP-violating phase γ

The weak phase γ is conventionally probed by theB _s→ρ ⁰ mode. The predicted rate is tiny. Even if aB _s→ρ ⁰ K _s rate difference could be established, it would not be clear that sin 2γ had been measured, because amplitudes with other weak phases may contribute significantly. Non-CP eigenstates, such asB _s →D _s ^± K ^?, have a two-fold advantage overB _s→ρ ⁰ K _s. Their rates are orders of magnitude above that forB _s→ρ ⁰ K _s, and they probe theCP-violating phase γ, without any contamination from other weak phases. Detailed time-dependent studies of non-CP eigenstates remove possible final-state phases and extract the weak phase γ.     

Evaluating the Frechet derivative of the matrix exponential

LetM _n denote the space ofn×n matrices. GivenX, ZM _n define

Energy dependence of the fast fragment of the target nucleus in high energy hadron-nucleus interaction

This paper presents an extensive study on the dependence of the mean number of the fast fragment of the target nucleus n _g on the incident beam energy in proton-nucleus interaction in emulsion in the range 6·2E ₀400 GeV/c. It has been observed that n _g decreases in the range 6·2E ₀200 GeV/c, then increases and attains an approximately steady value up to 400 GeV/c. It is very difficult to explain this behaviour with the help of the existing nuclear production models.The author would like to thank Prof A. J. Herz (CERN), Prof. K. D. Tolostov (Dubna, U.S.S.R.), Prof. P. L. Jain (State University of New York, U.S.A.), Prof. G. Giacomelly (Italy) for kindly supplying the exposed emulsion plates.     

THE EFFECTS OF FAR ULTRAVIOLET RADIATION ON RESPIRATION AND CATION ACCUMULATION BY ISOLATED MITOCHONDRIA OF PHASEOLUS VULGARIS

Abstract. The respiration rates and respiratory control ratios of isolated bean mitochondria have been measured following exposure to 0, 150, 300 and 900 J/m² of far UV radiation (190–300 nm) from a mercury vapour light source with 90% total radiant intensity at 254 nm. Loss of respiratory control occurred at 150 J/m² and inhibition of respiration was significant at the highest exposure dosage. The uptake of both ⁴⁵Ca and ⁸⁵Sr have been measured following a 10min incubation of isolated mitochondria with 2 m M cation. Significant decreases in cation accumulation were observed following exposure to 900 J/m². The effect seemed to be associated with loss of active transport of the ions as a result of respiratory uncoupling or reduced electron transport. There was no significant effect of storage on respiration or ion transport nor was there any indirect effect of irradiated suspending medium on mitochondria.     

Alkoxide Derived SrBi2Ta2O9 Phase Pure Powder and Thin Films

Phase pure powder and thin films of the novel ferroelectric materials SrBi₂Ta₂O₉ (SBT) have been prepared using the organic precursors. The xero-gel formed was dried and characterized using TGA and DTA to determine the organic burn out and crystallization temperature of SBT. Powder X-ray diffraction was used systematically to check the crystallinity of SBT. Phase pure SBT powder was formed as low as 650°C and thin films at 600°C in comparison to other earlier reported work. SEM micrographs show a grain size of ≈0.1 μm and show crack free films with a film thickness of 2 μm.     

A sensitive,specific method for the determination of tetraalkyllead compounds in air by gas chromatography/atomic absorption spectrometry

The development of a sensitive and specific method of determining individually the five tetraalkyllead compounds normally present in ambient air is described. The method is based on collection of the analytes on a porous polymer using a prefilter to destroy ozone and prevent decomposition of the sample during collection and storage. Two-stage thermal desorption, separation by gas chromatography and detection by modified flame atomic absorption spectrometry gives detection limits (3σ) of ca. 0.25 ng Pb m^?3 for tetramethyllead and 0.37 ng Pb m^?3 for tetraethyllead in an air sample of 80 dm³ collected over a 3–24 h period. Environmental sampling by this method in paralle with a wet chemical (iodine monochloride) method was used to validate the method. During the comparative study, higher organic lead levels were consistently found by the iodine monochloride method; it is postulated that this indicates the presence of vapour-phase tri-(or di)-alkyllead in excess of 1 ng Pb m^?3 in rural air. The versatility of the method is demonstrated by the results of atmospheric sampling at two locations, one rural and one at the kerbside in a city centre.