4,550 research outputs found

    Deflection of Rotating Symmetric Molecules by Inhomogeneous Fields

    Full text link
    We consider deflection of rotating symmetric molecules by inhomogeneous optical and static electric fields, compare results with the case of linear molecules, and find new singularities in the distribution of the scattering angle. Scattering of the prolate/oblate molecules is analyzed in detail, and it is shown that the process can be efficiently controlled by means of short and strong femtosecond laser pulses. In particular, the angular dispersion of the deflected molecules may be dramatically reduced by laser-induced molecular pre-alignment. We first study the problem by using a simple classical model, and then find similar results by means of more sophisticated methods, including the formalism of adiabatic invariants and direct numerical simulation of the Euler-Lagrange equations of motion. The suggested control scheme opens new ways for many applications involving molecular focusing, guiding, and trapping by optical and static fields

    Electric Deflection of Rotating Molecules

    Full text link
    We provide a theory of the deflection of polar and non-polar rotating molecules by inhomogeneous static electric field. Rainbow-like features in the angular distribution of the scattered molecules are analyzed in detail. Furthermore, we demonstrate that one may efficiently control the deflection process with the help of short and strong femtosecond laser pulses. In particular the deflection process may by turned-off by a proper excitation, and the angular dispersion of the deflected molecules can be substantially reduced. We study the problem both classically and quantum mechanically, taking into account the effects of strong deflecting field on the molecular rotations. In both treatments we arrive at the same conclusions. The suggested control scheme paves the way for many applications involving molecular focusing, guiding, and trapping by inhomogeneous fields

    Response to Comment on "Pairing and Phase Separation in a Polarized Fermi Gas"

    Full text link
    Zwierlein and Ketterle rely on subjective arguments and fail to recognize important differences in physical parameters between our experiment and theirs. We stand by the conclusions of our original report

    A double-helix neutron detector using micron-size B-10 powder

    Full text link
    A double-helix electrode configuration is combined with a 10^{10}B powder coating technique to build large-area (9 in ×\times 36 in) neutron detectors. The neutron detection efficiency for each of the four prototypes is comparable to a single 2-bar 3^3He drift tube of the same length (36 in). One unit has been operational continuously for 18 months and the change of efficiency is less than 1%. An analytic model for pulse heigh spectra is described and the predicted mean film thickness agrees with the experiment to within 30%. Further detector optimization is possible through film texture, power size, moderator box and gas. The estimated production cost per unit is less than 3k US\$ and the technology is thus suitable for deployment in large numbers

    Ramsey's Method of Separated Oscillating Fields and its Application to Gravitationally Induced Quantum Phaseshifts

    Full text link
    We propose to apply Ramsey's method of separated oscillating fields to the spectroscopy of the quantum states in the gravity potential above a vertical mirror. This method allows a precise measurement of quantum mechanical phaseshifts of a Schr\"odinger wave packet bouncing off a hard surface in the gravitational field of the earth. Measurements with ultra-cold neutrons will offer a sensitivity to Newton's law or hypothetical short-ranged interactions, which is about 21 orders of magnitude below the energy scale of electromagnetism.Comment: 7 pages, 6 figure

    Environmental Crime: The Use of Criminal Sanctions in Enforcing Environmental Laws

    Get PDF

    Antibody-mediated rejection after lung transplantation

    Get PDF
    Antibody-mediated rejection (AMR) has been identified as a significant form of acute allograft dysfunction in lung transplantation. The development of consensus diagnostic criteria has created a uniform definition of AMR; however, significant limitations of these criteria have been identified. Treatment modalities for AMR have been adapted from other areas of medicine and data on the effectiveness of these therapies in AMR are limited. AMR is often refractory to these therapies, and graft failure and death are common. AMR is associated with increased rates of chronic lung allograft dysfunction (CLAD) and poor long-term survival. In this review, we discuss the history of AMR and describe known mechanisms, application of the consensus diagnostic criteria, data for current treatment strategies, and long-term outcomes. In addition, we highlight current gaps in knowledge, ongoing research, and future directions to address these gaps. Promising diagnostic techniques are actively being investigated that may allow for early detection and treatment of AMR. We conclude that further investigation is required to identify and define chronic and subclinical AMR, and head-to-head comparisons of currently used treatment protocols are necessary to identify an optimal treatment approach. Gaps in knowledge regarding the epidemiology, mechanisms, diagnosis, and treatment of AMR continue to exist and future research should focus on these aspects

    Transverse imaging and simulation of dsDNA electrophoresis in microfabricated glass channels

    Full text link
    We have observed the non-uniform distribution of DNA molecules during PAGE in a microfabricated system. Confocal laser scanning microscopy was used to visualize fluorescently labeled DNA during electrophoretic migration. The distribution of double-stranded DNA larger than 100 bp is observed to transition from a center-biased motion on the transverse plane 1 cm downstream from injection to an edge-biased motion 2 cm downstream. Although this distribution increased with increasing dsDNA size in a cross-linked gel, no similar distribution was found with the same dsDNA molecules in a linear polyacrylamide solution (6%). Simulations of DNA distribution in gels suggest that DNA distribution non-uniformities may be caused by biased electrophoretic migration resulting from motion in an inhomogeneous gel system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61440/1/4768_ftp.pd

    COVID-19 Response: Resources for Small and Mid-Size Farms in Mississippi

    Get PDF
    The COVID-19 pandemic presents a number of new and difficult challenges for families, small business owners, and food producers across the country. This Issue Brief provides an overview of the resources available to small and mid-size farms facing such challenges in Mississippi. The first section outlines current benefit programs that these farms can utilize, including loans and unemployment benefits, as a result of the Coronavirus Aid, Relief, and Economic Security (CARES) Act and related federal actions. The second section provides policies that the State of Mississippi could enact to provide additional assistance to farms dealing with the crisis
    • …
    corecore