2,052 research outputs found
Feshbach spectroscopy of an ultracold Rb-Cs mixture
No full textThis thesis reports the observation of interspecies Feshbach resonances in an ultracold mixture of Rb and Cs atoms. A versatile combined magnetic and optical potential has been designed and constructed which is capable of bringing both and to degeneracy, and reaching high phase-space density in . High phase-space density mixtures are the first step required in the production of ultracold polar molecules, the topic of much current research.
The apparatus capitalises on the efficient capture of atoms by a magnetic trap from a magneto-optical trap, and the efficient sympathetic cooling of Cs by Rb therein. Upon transfer to the crossed optical dipole trap condensates in excess of atoms and approximately atoms are produced after direct evaporation and gravito-magnetic tilting of the potential. The observation of six interspecies - Feshbach resonances are reported, three of which had only been predicted theoretically, allowing testing and development of the theoretical model. Furthermore, the extrapolation of this model has predicted numerous Feshbach resonances between and , none of which have been experimentally observed prior to this work. The versatile nature of this apparatus is discussed, including the application of the current system to cooling of . Initial experiments observed seven interspecies resonances, including a broad s-wave resonance at a magnetic field of G which is in excellent agreement with the theoretical prediction. Further work has revealed that fourteen Feshbach resonances exist in the 0-700 G magnetic field range between and atoms in the and states, respectively. Several of these resonances would be ideal for magneto-association of RbCs molecules, prior to transfer to the rovibrational ground-state
A Quantum Degenerate Mixture of Rb and Cs
No full textThis thesis reports the formation of a dual-species Bose-Einstein condensate of Rb and Cs in the same trapping potential. Quantum degenerate mixtures exhibit rich physics inaccessible to single species experiments and provide an ideal starting point for the creation of ultracold dipolar molecules. These molecules offer a wealth of new research avenues including precision metrology, quantum simulation and computation.
The experimental method exploits the efficient sympathetic cooling of Cs via elastic collisions with Rb, initially in a magnetic quadrupole trap and subsequently in a levitated optical trap. Evaporative cooling in the dipole trap must compete against a high interspecies three-body inelastic collision rate \mbox{~cms}. The two condensates each contain up to \mbox{} atoms and exhibit a striking phase separation, revealing the mixture to be immiscible due to strong repulsive interspecies interactions. Sacrificing all the Rb during the cooling leads to the creation of single-species Cs condensates of up to \mbox{} atoms. In addition this thesis reports the observation of an interspecies Feshbach resonance at 181.7(5)~G and the creation of a pure sample of Cs molecules via magneto-association on the 4(g)4 resonance at 19.8~G. These results represent important steps towards the creation of ultracold polar RbCs molecules
Mean intraocular pressure (IOP) and its difference with limits of agreement from Bland and Altman plots as measured by rebound tonometry (RB) and applanation tonometry (AP) at each increasing and decreasing atmospheric pressure level during the experiment.
No full textMean intraocular pressure (IOP) and its difference with limits of agreement from Bland and Altman plots as measured by rebound tonometry (RB) and applanation tonometry (AP) at each increasing and decreasing atmospheric pressure level during the experiment.</p
CONSORT for Reporting Randomized Controlled Trials in Journal and Conference Abstracts: Explanation and Elaboration
No full textBACKGROUND: Clear, transparent, and sufficiently detailed abstracts of conferences and journal articles related to randomized controlled trials (RCTs) are important, because readers often base their assessment of a trial solely on information in the abstract. Here, we extend the CONSORT (Consolidated Standards of Reporting Trials) Statement to develop a minimum list of essential items, which authors should consider when reporting the results of a RCT in any journal or conference abstract. METHODS AND FINDINGS: We generated a list of items from existing quality assessment tools and empirical evidence. A three-round, modified-Delphi process was used to select items. In all, 109 participants were invited to participate in an electronic survey; the response rate was 61%. Survey results were presented at a meeting of the CONSORT Group in Montebello, Canada, January 2007, involving 26 participants, including clinical trialists, statisticians, epidemiologists, and biomedical editors. Checklist items were discussed for eligibility into the final checklist. The checklist was then revised to ensure that it reflected discussions held during and subsequent to the meeting. CONSORT for Abstracts recommends that abstracts relating to RCTs have a structured format. Items should include details of trial objectives; trial design (e.g., method of allocation, blinding/masking); trial participants (i.e., description, numbers randomized, and number analyzed); interventions intended for each randomized group and their impact on primary efficacy outcomes and harms; trial conclusions; trial registration name and number; and source of funding. We recommend the checklist be used in conjunction with this explanatory document, which includes examples of good reporting, rationale, and evidence, when available, for the inclusion of each item. CONCLUSIONS: CONSORT for Abstracts aims to improve reporting of abstracts of RCTs published in journal articles and conference proceedings. It will help authors of abstracts of these trials provide the detail and clarity needed by readers wishing to assess a trial's validity and the applicability of its results.Sally Hopewell, Mike Clarke, David Moher, Elizabeth Wager, Philippa Middleton, Douglas G. Altman, Kenneth F. Schulz, and the CONSORT Grou
PharmGKB summary: very important pharmacogene information for PTGS2
No full textThorn CF, Grosser T, Klein TE, Altman RB. PharmGKB summary: very important pharmacogene information for PTGS2. Pharmacogenetics and Genomics. 2011;21(9):607-613
Liquid structure of Rb-Hg alloys studied by neutron diffraction
No full textThe structures of liquid Rb–Hg alloys were studied as a function of composition by neutron diffraction. In the intermediate Rb concentration range, the obtained structure factors show a small prepeak, which may be an evidence of the formation of Hg polyanion units in liquids. The Reverse Monte Carlo (RMC) analysis was applied to separate the total radial distribution function into the corresponding partial radial distribution functions. Up to 10 at.% Rb, no obvious changes are found for the first peak position of the partial radial distribution functions of the Hg–Hg pair and that of the Hg–Rb pair. The first peak position between the Hg–Rb pairs increases above 20 at.% Rb. In addition to the first peak, a subpeak between Hg–Hg pairs can be seen in the large distance. At 60 at.% Rb, the nearest neighbor distance between Hg atoms shows the closest value in the concentration range studied. These results indicate that with the progress of charge transfer the solvation structure in the dilute Rb concentration range changes into the structure containing polyanions composed of Hg species
Visualization of Biomedical Data
No full textThe rapid increase in volume and complexity of biomedical data requires changes in research, communication, training, and clinical practices. This includes learning how to effectively integrate automated analysis with high-data-density visualizations that clearly express complex phenomena. In this review, we summarize key principles and resources from data visualization research that address this difficult challenge. We then survey how visualization is being used in a selection of emerging, biomedical research areas, including: 3D genomics, single-cell RNA-seq, the protein structure universe, phosphoproteomics, augmented-reality surgery, and metagenomics. While specific areas need highly tailored visualization tools, there are, however, common visualization challenges that can be addressed with general methods, and strategies, and challenges. Unfortunately, poor visualization practices are also common: ; however, there are strong good prospects for improvements and innovations that will revolutionize how we see and think about our data. We outline initiatives aimed at fostering these improvements via better tools, peer-to-peer learning, and interdisciplinary collaboration with computer scientists, science communicators, and graphic designers
Celecoxib pathways: pharmacokinetics and pharmacodynamics
No full textGong L, Thorn CF, Bertagnolli MM, Grosser T, Altman RB, Klein TE. Celecoxib pathways: pharmacokinetics and pharmacodynamics. Pharmacogenetics and Genomics. 2012;22(4):310-318
Fractional Edge Cover Number of Model RB
No full textModel RB is a random constraint satisfaction problem with a growing domain size, which exhibits exact phase transition phenomena. Many hard instances with planted solutions can be generated via Model RB, to be used as benchmarks for algorithmic competitions and researches. In the past, some structural parameters of constraint hypergraphs are analyzed to show hardness of Model RB, such as hinge width, decycling number, treewidth, and hypertree width. In this paper, one more structural parameter of constraint hypergraphs of Model RB, namely the fractional edge cover number, is analyzed. We show upper and lower bounds on the fractional edge cover number of Model RB. In particular, the fractional edge cover number of Model RB is shown to be asymptotically linear in the number of variables, like hinge width, decycling number, treewidth and hypertree width. These results together provide further evidences on the hardness of Model RB.EICPCI-S(ISTP)[email protected]
MILLIMETER-WAVE SPECTROSCOPY OF COLD RB ATOMS
No full textAuthor Institution: Department of Physics, University of Virginia, McCormick Road, Charlottesville, Virginia 22903Cold Rb atoms were prepared by magneto-optical trap. Millimeter-wave has been used to drive nd to (n-2)f one-photon and nd to (n-1)g () two-photon transitions. Quantum defects of f and g states of Rb were calculated. Full analyses will be presented. }
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