Controlling Molecular Scattering by Laser-Induced Field-Free Alignment

We consider deflection of polarizable molecules by inhomogeneous optical fields, and analyze the role of molecular orientation and rotation in the scattering process. It is shown that molecular rotation induces spectacular rainbow-like features in the distribution of the scattering angle. Moreover, by preshaping molecular angular distribution with the help of short and strong femtosecond laser pulses, one may efficiently control the scattering process, manipulate the average deflection angle and its distribution, and reduce substantially the angular dispersion of the deflected molecules. We provide quantum and classical treatment of the deflection process. The effects of strong deflecting field on the scattering of rotating molecules are considered by the means of the adiabatic invariants formalism. This new control scheme opens new ways for many applications involving molecular focusing, guiding and trapping by optical and static fields

Increasing Incidence Within PubMed of the Use of the Misspelling Pruritis (Sic) Instead of Pruritus for Itch

Writers generally benefit from word processing technology, and the use of other forms of formal writing such as typewriters is archaic. The first stand-alone spell checker programs originated in the early 1980s, and by 1995 they were embedded within word processing programs such as Word 95 (1). With the ubiquity of such software, spelling errors in the medical literature should be extinct. Yet, as a reader of the medical literature with an interest in itch, this author is impressed with the numbers of misspellings of the word «pruritus.» The word pruritus is derived from the Latin pruritus, past participle of prurire “to itch” (2) To assess the frequency and characteristics of the misspellings of this word, a PubMed search was undertaken

Development of a steam powered sports car

Thesis (B.S.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1957.MIT copy bound with: Test and modification of a density compensated orifice flowmeter / Allan Eckhaus. 1957.Bibliography: leaf [60].by William B. Fleischer and Sidney Zafran.B.S

Calculation of Infrared-Divergent Feynman Diagrams with Zero Mass Threshold

Two-loop vertex Feynman diagrams with infrared and collinear divergences are investigated by two independent methods. On the one hand, a method of calculating Feynman diagrams from their small momentum expansion extended to diagrams with zero mass thresholds is applied. On the other hand, a numerical method based on a two-fold integral representation is used. The application of the latter method is possible by using lightcone coordinates in the parallel space. The numerical data obtained with the two methods are in impressive agreement.Comment: 20 pages, Latex with epsf-figures, References updated, to appear in Z.Phys.

Exploring CP Violation through Correlations in B --> pi K, B_d --> pi^+pi^-, B_s --> K^+K^- Observable Space

We investigate allowed regions in observable space of B --> pi K, B_d --> pi^+pi^- and B_s --> K^+K^- decays, characterizing these modes in the Standard Model. After a discussion of a new kind of contour plots for the $B\to\pi K$ system, we focus on the mixing- induced and direct CP asymmetries of the decays B_d --> pi^+pi^- and B_s--> K^+K^-. Using experimental information on the CP-averaged B_d --> pi^{+/-}K^{+/-} and B_d --> pi^+pi^- branching ratios, the relevant hadronic penguin parameters can be constrained,implying certain allowed regions in observable space. In the case of B_d --> pi^+pi^-, an interesting situation arises now in view of the recent B-factory measurements of CP violation in this channel, allowing us to obtain new constraints on the CKM angle gamma as a function of the B^0_d--\bar{B^0_d} mixing phase phi_d=2beta, which is fixed through A_{CP}^{mix}(B_d --> J/psi K_S) up to a twofold ambiguity. If we assume that A_{CP}^{mix}(B_d --> pi^+pi^-) is positive, as indicated by recent Belle data, and that phi_d is in agreement with the ``indirect'' fits of the unitarity triangle, also the corresponding values for gamma around 60 degrees can be accommodated. On the other hand, for the second solution of phi_d, we obtain a gap around gamma ~ 60 degrees. The allowed region in the space of A_{CP}^{mix}(B_s --> K^+K^-) and A_{CP}^{dir}(B_s --> K^+K^-) is very constrained in the Standard Model, thereby providing a narrow target range for run II of the Tevatron and the experiments of the LHC era.Comment: 34 pages, LaTeX, 12 figures. More detailed introduction and a few Comments added, conclusions unchanged. To appear in Phys. Rev.

Isotope fractionation and sulfur metabolism by pure and enrichment cultures of elemental sulfur-disproportionating bacteria

We have explored the sulfur metabolism and accompanying fractionation of sulfur isotopes during the disproportionation of elemental sulfur by seven different enrichments and three pure bacterial cultures. Cultures were obtained from both marine and freshwater environments. In all cases appreciable fractionation accompanied elemental sulfur disproportionation, with two ranges of fractionation observed. All cultures except Desulfobulbus propionicus produced sulfide depleted in S-34 by between 5.5 and 6.9 per mil (avg of 6.3 per mi) and sulfate enriched in S-34 by between 17.1 and 20.2 per mil (avg of 18.8 per ml). The narrow range of fractionations suggests a conserved biochemistry for the disproportionation of elemental sulfur by many different marine and freshwater bacteria. Fractionations accompanying elemental sulfur disproportionation by Db. propionicus were nearly twice as great as the others, suggesting a different cellular level pathway of sulfur processing by this organism. In nearly every case pyrite formation accompanied the disproportionation of elemental sulfur. By using sulfur isotopes as a tracer of sulfur source, we could identify that pyrite formed both by the addition of elemental sulfur to FeS and from reaction between FeS and H2S. Both processes were equally fast and up to 10(4)-10(5) times faster than expected from the reported kinetics of inorganic pyrite-formation reactions. We speculate that bacteria may have enhanced rates of pyrite formation in our experimental systems. The organisms explored here have different strategies for growth and survival, and they may be active in environments ranging from dissolved sulfide-poor suboxic sediments to interfaces supporting steep opposing gradients of oxygen and sulfide. A large environmental range, combined with high bacterial numbers, significant isotope fractionations, and a possible role in pyrite formation, make elemental sulfur-disproportionating bacteria potentially significant actors in the sedimentary cycling of sulfur compounds

Exploring CP Violation with BcB_c Decays

We point out that the pure ``tree'' decays $B_c^\pm\to D^\pm_s D$ are particularly well suited to extract the CKM angle $\gamma$ through amplitude relations. In contrast to conceptually similar strategies using $B^\pm\to K^\pm D$ or $B_d\to K^{\ast0} D$ decays, the advantage of the $B_c$ approach is that the corresponding triangles have three sides of comparable length and do not involve small amplitudes. Decays of the type $B_c^\pm\to D^\pm D$ -- the $U$-spin counterparts of $B_c^\pm\to D^\pm_s D$ -- can be added to the analysis, as well as channels, where the $D^\pm_s$- and $D^\pm$-mesons are replaced by higher resonances.Comment: 9 pages, LaTeX, 3 figures, reference adde

Weak Phase γ\gamma From Ratio of B→KπB \to K \pi Rates

The ratio of partial decay rates for charged and neutral $B$ mesons to $K \pi$ final states provides information on the weak phase $\gamma \equiv {\rm Arg} (V_{ub}^*)$ when augmented with information on the CP-violating asymmetry in the $K^\pm \pi^\mp$ mode. The requirements for a useful determination of $\gamma$ are examined in the light of present information about the decays $B^0 \to K^+ \pi^-$, $B^+ \to K^0 \pi^+$, and the corresponding charge-conjugate modes. The effects of electroweak penguins and rescattering corrections are noted, and proposals are made for estimating and measuring their importance.Comment: 16 pages, latex, 3 figures, revised version sent to Phys. Rev.

Relativistic description of electron scattering on the deuteron

Within a quasipotential framework a relativistic analysis is presented of the deuteron current. Assuming that the singularities from the nucleon propagators are important, a so-called equal time approximation of the current is constructed. This is applied to both elastic and inelastic electron scattering. As dynamical model the relativistic one boson exchange model is used. Reasonable agreement is found with a previous relativistic calculation of the elastic electromagnetic form factors of the deuteron. For the unpolarized inelastic electron scattering effects of final state interactions and relativistic corrections to the structure functions are considered in the impulse approximation. Two specific kinematic situations are studied as examples.Comment: (19 pages in revtex + 15 figures not included, available upon request.) report THU-93-10

Innovation in the European chemical industry

Firms in the European chemical industry have been among the most successful firms world wide. However, they have had to undertake severe restucturing in order to maintain their market position. These efforts focused in particular on strengthening their innovative capability as product and process innovation have become the most decisive factors in global competition. In order to improve the innovative conditions, the European Commission has supported the Community Innovation Survey (CIS). 1992/1993 was the first time that large-scale harmonised innovation surveys were carried out in all Member States of the European Union. This study uses the CIS micro data from nearly 2000 European chemical firms. This study focuses on the identification of innovative trends within the chemical industry between 1984 and 1993. Using data from annual reports of nine selected European stock companies, the study identifies those areas of the chemical industry currently having the highest innovative potential. Three speciality categories are identified as having the highest number of innovations during this ten year period: chemicals, paints/varnishes, and plastics. -- Obwohl viele europäische Unternehmen der chemischen Industrie in den vergangenen Jahrzehnten zu den erfolgreichsten in der Welt zählten, mußten sie sich Anfang der neunziger Jahre einem gravierenden Strukturwandel unterziehen, um ihre Position behaupten zu können. Die Fähigkeit der Unternehmen, Innovationen hervorzubringen, stand und steht dabei im Mittelpunkt. Mit dem Ziel, die Rahmenbedingungen für Innovationen zu verbessern, führte die EU-Kommission 1993 eine europaweite Innovationserhebung, den Community Innovation Survey (CIS) durch. In dieser Studie wurden die anonymisierten Antworten von nahezu 2000 Unternehmen der chemischen Industrie analysiert. Um Innovationstrends aufzuzeigen zu können, wurden darüber hinaus Geschäftsberichte von neun großen europäischen Chemieunternehmen ausgewertet. So wurden die Sparten Spezialitäten, Farben/Lacke und Kunststoffe als diejenigen Sparten identifiziert, die im Untersuchungszeitraum (1984-1993) die meisten Innovationen aufwiesen.