91 research outputs found

    A skeleton approximate solution of the Einstein field equations for multiple black-hole systems

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    An approximate analytical and non-linear solution of the Einstein field equations is derived for a system of multiple non-rotating black holes. The associated space-time has the same asymptotic structure as the Brill-Lindquist initial data solution for multiple black holes. The system admits an Arnowitt-Deser-Misner (ADM) Hamiltonian that can particularly evolve the Brill-Lindquist solution over finite time intervals. The gravitational field of this model may properly be referred to as a skeleton approximate solution of the Einstein field equations. The approximation is based on a conformally flat truncation, which excludes gravitational radiation, as well as a removal of some additional gravitational field energy. After these two simplifications, only source terms proportional to Dirac delta distributions remain in the constraint equations. The skeleton Hamiltonian is exact in the test-body limit, it leads to the Einsteinian dynamics up to the first post-Newtonian approximation, and in the time-symmetric limit it gives the energy of the Brill-Lindquist solution exactly. The skeleton model for binary systems may be regarded as a kind of analytical counterpart to the numerical treatment of orbiting Misner-Lindquist binary black holes proposed by Gourgoulhon, Grandclement, and Bonazzola, even if they actually treat the corotating case. Along circular orbits, the two-black-hole skeleton solution is quasi-stationary and it fulfills the important property of equality of Komar and ADM masses. Explicit calculations for the determination of the last stable circular orbit of the binary system are performed up to the tenth post-Newtonian order within the skeleton model.Comment: 15 pages, 1 figure, submitted to Phys. Rev. D, 3 references added, minor correction

    Cosmic microwave background anisotropies in multi-connected flat spaces

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    This article investigates the signature of the seventeen multi-connected flat spaces in cosmic microwave background (CMB) maps. For each such space it recalls a fundamental domain and a set of generating matrices, and then goes on to find an orthonormal basis for the set of eigenmodes of the Laplace operator on that space. The basis eigenmodes are expressed as linear combinations of eigenmodes of the simply connected Euclidean space. A preceding work, which provides a general method for implementing multi-connected topologies in standard CMB codes, is then applied to simulate CMB maps and angular power spectra for each space. Unlike in the 3-torus, the results in most multi-connected flat spaces depend on the location of the observer. This effect is discussed in detail. In particular, it is shown that the correlated circles on a CMB map are generically not back-to-back, so that negative search of back-to-back circles in the WMAP data does not exclude a vast majority of flat or nearly flat topologies.Comment: 33 pages, 19 figures, 1 table. Submitted to PR

    Teleportation of the one-qubit state with environment-disturbed recovery operations

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    We study standard protocol P0\mathcal{P}_0 for teleporting the one-qubit state with both the transmission process of the two qubits constitute the quantum channel and the recovery operations performed by Bob disturbed by the decohering environment. The results revealed that Bob's imperfect operations do not eliminate the possibility of nonclassical teleportation fidelity provided he shares an ideal channel state with Alice, while the transmission process is constrained by a critical time t0,ct_{0,c} longer than which will result in failure of P0\mathcal{P}_0 if the two qubits are corrupted by the decohering environment. Moreover, we found that under the condition of the same decoherence rate γ\gamma, the teleportation protocol is significantly more fragile when it is executed under the influence of the noisy environment than those under the influence of the dissipative and dephasing environments.Comment: 8 pages, 4 figure

    Characteristics of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) rRNA genes of Apis mellifera (Insecta: Hymenoptera): structure, organization, and retrotransposable elements

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    As an accompanying manuscript to the release of the honey bee genome, we report the entire sequence of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) ribosomal RNA (rRNA)-encoding gene sequences (rDNA) and related internally and externally transcribed spacer regions of Apis mellifera (Insecta: Hymenoptera: Apocrita). Additionally, we predict secondary structures for the mature rRNA molecules based on comparative sequence analyses with other arthropod taxa and reference to recently published crystal structures of the ribosome. In general, the structures of honey bee rRNAs are in agreement with previously predicted rRNA models from other arthropods in core regions of the rRNA, with little additional expansion in non-conserved regions. Our multiple sequence alignments are made available on several public databases and provide a preliminary establishment of a global structural model of all rRNAs from the insects. Additionally, we provide conserved stretches of sequences flanking the rDNA cistrons that comprise the externally transcribed spacer regions (ETS) and part of the intergenic spacer region (IGS), including several repetitive motifs. Finally, we report the occurrence of retrotransposition in the nuclear large subunit rDNA, as R2 elements are present in the usual insertion points found in other arthropods. Interestingly, functional R1 elements usually present in the genomes of insects were not detected in the honey bee rRNA genes. The reverse transcriptase products of the R2 elements are deduced from their putative open reading frames and structurally aligned with those from another hymenopteran insect, the jewel wasp Nasonia (Pteromalidae). Stretches of conserved amino acids shared between Apis and Nasonia are illustrated and serve as potential sites for primer design, as target amplicons within these R2 elements may serve as novel phylogenetic markers for Hymenoptera. Given the impending completion of the sequencing of the Nasonia genome, we expect our report eventually to shed light on the evolution of the hymenopteran genome within higher insects, particularly regarding the relative maintenance of conserved rDNA genes, related variable spacer regions and retrotransposable elements

    Earth as a Tool for Astrobiology—A European Perspective

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    Eltrombopag increases plasma rosuvastatin exposure in healthy volunteers

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    10.1111/j.1365-2125.2011.03972.xBritish Journal of Clinical Pharmacology722321-329BCPH

    Liposomal Bupivacaine Versus Bupivacaine for Intercostal Nerve Blocks in Thoracic Surgery: A Retrospective Analysis.

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    Item does not contain fulltextBACKGROUND: Liposomal bupivacaine (LipoB), delivered via intercostal nerve blocks (ICNBs), is increasingly being used for postoperative pain control in thoracic surgery patients, but there is limited data on its effectiveness when compared to standard bupivacaine. OBJECTIVE: We sought to compare postoperative opioid use, pain control, and length of stay (LOS) in patients undergoing thoracic surgery with LipoB ICNBs vs patients undergoing thoracic surgery with ICNBs using standard bupivacaine. STUDY DESIGN: A retrospective analysis. SETTING: Research took place in a tertiary academic medical center. METHODS: A transition in the standard of care from standard bupivacaine to LipoB for ICNBs in March of 2014 allowed us to compare 2 cohorts: patients who received bupivacaine ICNBs from January 2013 through February of 2014 and patients who received LipoB ICNBs from March 2015 through November 2017. We included patients who underwent thoracic surgery for lung cancer using robotic-assisted thoracic surgery (RATS), video-assisted thoracic surgery (VATS), or traditional open thoracotomy, and documentation of ICNB in the operative note. We collected data on pain scores (Visual Analog Scale [VAS]) and opioid consumption (converted to oral morphine equivalents [OMEs]) intraoperatively, on postoperative day (POD) 0, POD 1, POD 2, and POD 3. We also analyzed data on length of stay [LOS]. A primary analysis was performed on the effects of LipoB vs bupivacaine across all surgery types on opioid consumption, pain scores, and LOS with a secondary analysis on the same endpoints per individual surgery type. RESULTS: A total of 129 patients were included from the predefined study periods (n = 62 LipoB and n = 67 standard bupivacaine). Across all surgery types, LipoB decreased opioid utilization vs standard bupivacaine (P < .01). Post-hoc testing revealed that this difference existed intraoperatively (55 ± 5 vs 69 ± 4 mg OME, P = .03) and on POD 0 (44 ± 6 vs 68 ± 6 mg OME, P < .01). Surgical subtype analysis revealed that this difference was mostly driven by lower opioid consumption in patients undergoing RATS. When compared across all surgery types, LipoB vs bupivacaine did not affect postoperative pain scores. However, subgroup analysis showed that pain scores were lower in the LipoB vs standard bupivacaine group undergoing VATS on POD 0, 1, and 2. The LOS across all thoracic surgery types was lower in the LipoB group when compared to the standard bupivacaine group (median, 4 days [IQR 2.0-6.0] vs median, 5 days [IQR 3.0-8.0], P < .01). Subgroup analysis showed that the LOS in patients undergoing VATS with LipoB ICNBs was shorter compared to patients receiving bupivacaine ICNBs. LIMITATIONS: The retrospective nature of this study makes it prone to several types of bias. CONCLUSION: ICNBs with LipoB for thoracic surgery leads to lower opioid consumption and shorter LOS when compared to ICNBs with standard bupivacaine. The benefit of LipoB over standard bupivacaine for ICNBs appears especially relevant in VATS or RATS procedures. KEY WORDS: Intercostal nerve block, liposomal bupivacaine, RATS, regional anesthesia, robotic-assisted thoracoscopic surgery, thoracotomy, VATS, video-assisted thoracoscopic surgery.1 juni 202

    Evaluation of a Tensile Test for Direct Filling Resins

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67602/2/10.1177_00220345700490023801.pd
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