1,840 research outputs found

    Quenching of lamellar ordering in an n-alkane embedded in nanopores

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    We present an X-ray diffraction study of the normale alkane nonadecane C_{19}H_{40} embedded in nanoporous Vycor glass. The confined molecular crystal accomplishes a close-packed structure by alignment of the rod-like molecules parallel to the pore axis while sacrificing one basic principle known from the bulk state, i.e. the lamellar ordering of the molecules. Despite this disorder, the phase transitions observed in the confined solid mimic the phase behavior of the 3D unconfined crystal, though enriched by the appearance of a true rotator phase known only from longer alkane chains.Comment: 7 pages, 3 figure

    Irreversible Quantum Mechanics in the Neutral K-System

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    The neutral Kaon system is used to test the quantum theory of resonance scattering and decay phenomena. The two dimensional Lee-Oehme-Yang theory with complex Hamiltonian is obtained by truncating the complex basis vector expansion of the exact theory in Rigged Hilbert space. This can be done for K_1 and K_2 as well as for K_S and K_L, depending upon whether one chooses the (self-adjoint, semi-bounded) Hamiltonian as commuting or non-commuting with CP. As an unexpected curiosity one can show that the exact theory (without truncation) predicts long-time 2 pion decays of the neutral Kaon system even if the Hamiltonian conserves CP.Comment: 36 pages, 1 PostScript figure include

    Success With Extended-Infusion Meropenem After Recurrence of Baclofen Pump-Related Achromobacter Xylosoxidans Meningitis in an Adolescent

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    A 13-year-old female experienced a recurrence of baclofen pump-related central nervous system (CNS) infection caused by Achromobacter, despite absence of retained foreign material. Due to the failure of meropenem (120 mg/kg/d in divided doses every 8 hours and infused over 30 minutes) in the initial infection, the dose was infused over 4 hours during the recurrence. Meropenem is an antibiotic for which efficacy is time dependent, and 4-hour versus 30-minute infusions have been shown to prolong the time the concentration of the antibiotic exceeds the minimum inhibitory concentration (MIC) of the organism at the site of infection (T\u3eMIC). Meropenem serum concentrations were obtained and indicated that T\u3eMIC was at least 75% of the dosing interval. Our patient improved with no noted recurrences or adverse effects on the extended-infusion meropenem regimen. Utilization of extended-infusion beta-lactam dosing whenever possible in the treatment of serious infections caused by gram-negative organisms should be considered, as this dosing appears to be safe and improves the probability of achieving pharmacokinetic/pharmacodynamic goals

    Identification of Quantitative Trait Loci Affecting Female Reproductive Traits in a Multigeneration Meishan-White Composite Swine Population

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    A multigeneration crossbred Meishan- White composite resource population was used to identify quantitative trait loci (QTL) for age at first estrus (AP) and the components of litter size: ovulation rate (OR; number of ova released in an estrous period) and uterine capacity (UC). The population was established by reciprocally mating Meishan (ME) and White composite (WC) pigs. Resultant F1 females were mated to either ME or WC boars to produce backcross progeny (BC) of either ¾ WC ¼ ME or ¼ WC ¾ ME. To produce the next generation (F3) , ¾ WC ¼ ME animals were mated to ¼ WC ¾ ME animals yielding half-blood (½ WC ½ ME) progeny. A final generation (F4) was produced by inter se mating F3 animals. Measurements for AP and OR were recorded on 101 BC, 389 F3, and 110 F4 gilts, and UC data were from 101 BC and 110 F4 first parity litters. A genomic scan was conducted with markers (n = 157) spaced &#;20 cM apart. All parental, F1, BC, and F4 animals but only 84 F3 animals were genotyped and included in this study. The QTL analysis fitted a QTL at 1-cM intervals throughout the genome, and QTL effects were tested using approximate genome-wide significance levels. For OR, a significant (E[false positive] \u3c .05) QTL was detected on chromosome 8, suggestive (E[false positive] \u3c 1.0) QTL were detected on chromosomes 3 and 10, and two additional regions were detected that may possess a QTL (E[false positive] \u3c 2.0) on chromosomes 9 and 15. Two regions possessed suggestive evidence for QTL affecting AP on chromosomes 1 and 10, and one suggestive region on chromosome 8 was identified for UC. Further analyses of other populations of swine are necessary to determine the extent of allelic variation at the identified QTL

    Testing of CP, CPT and causality violation with the light propagation in vacuum in presence of the uniform electric and magnetic fields

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    We have considered the structure of the fundamental symmetry violating part of the photon refractive index in vacuum in the presence of constant electric and magnetic fields. This part of the refractive index can, in principle, contain CPT symmetry breaking terms. Some of the terms violate Lorentz invariance, whereas the others violate locality and causality. Estimates of these effects, using laser experiments are considered.Comment: 12 page

    Semiclassical Extremal Blackholes

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    Extremal black holes are studied in a two dimensional model motivated by a dimensional reduction from four dimensions. Their quantum corrected geometry is calculated semiclassically and a mild singularity is shown to appear at the horizon. Extensions of the geometry past the horizon are not unique but there are continuations free from malevolent singularities. A few comments are made about the relevance of these results to four dimensions and to the study of black hole entropy and information loss.Comment: 16 pages, 2 figures upon request, CALT-68-1833 - (new version corrects omissions in previous list of references

    Relaxation of the Dynamical Gluino Phase and Unambiguous Electric Dipole Moments

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    We propose a new axionic solution of the strong CP problem with a Peccei-Quinn mechanism using the gluino rather than quarks. The spontaneous breaking of this new global U(1) at 10^{11} GeV also generates the supersymmetry breaking scale of 1 TeV (solving the so-called \mu problem at the same time) and results in the MSSM (Minimal Supersymmetric Standard Model) with R parity conservation. In this framework, electric dipole moments become calculable without ambiguity.Comment: Typos corrected and a footnote added, 10 p

    Fully supersymmetric CP violations in the kaon system

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    We show that, on the contrary to the usual claims, fully supersymmetric CP violations in the kaon system are possible through the gluino mediated flavor changing interactions. Both ϵK\epsilon_K and Re(ϵ/ϵK){\rm Re} (\epsilon' / \epsilon_K) can be accommodated for relatively large tanβ\tan\beta without any fine tunings or contradictions to the FCNC and EDM constraints.Comment: Contribution to the Proceedings of ICHEP2000, Osaka, 200
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