375 research outputs found

    Experimental study of the Ca2 1S+1S asymptote

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    The filtered laser excitation technique was applied for measuring transition frequencies of the Ca2_2 B-X system from asymptotic levels of the X1Σg+^1\Sigma_{\mathrm g}^{+} ground state reaching v=38v''=38. That level has an outer classical turning point of about 20~\AA which is only 0.2 \rcm below the molecular 1^1S+1+^1S asymptote. Extensive analysis of the spectroscopic data, involving Monte Carlo simulation, allowed for a purely experimental determination of the long range parameters of the potential energy curve. The possible values of the s-wave scattering length could be limited to be between 250a0a_0 and 1000a0a_0.Comment: 10 pages, 7 figure

    KRb Feshbach Resonances: Modeling the interatomic potential

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    We have observed 28 heteronuclear Feshbach resonances in 10 spin combinations of the hyperfine ground states of a 40K 87Rb mixture. The measurements were performed by observing the loss rates from an atomic mixture at magnetic fields between 0 and 700 G. This data was used to significantly refine an interatomic potential derived from molecular spectroscopy, yielding a highly consistent model of the KRb interaction. Thus, the measured resonances can be assigned to the corresponding molecular states. In addition, this potential allows for an accurate calculation of the energy differences between highly excited levels and the rovibrational ground level. This information is of particular relevance for the formation of deeply bound heteronuclear molecules. Finally, the model is used to predict Feshbach resonances in mixtures of 87Rb combined with 39K or 41K.Comment: 4 pages, 3 figure

    Principles of the therapy of bone infections in adult extremities: Are there any new developments?

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    Septic diseases of the bone and immediately surrounding soft tissues can be differentiated into osteitis or osteomyelitis. Both are a most serious diagnosis in modern traumatology and orthopaedic surgery. The basis for treatment is a highly specific, problem-adapted therapy with a defined strategy, the paramount goal being to preserve the stable weightbearing bones, maintain a good mechanical axis with correctly working muscles and joints, and avoid permanent disability. “State-of-the-art” therapy of osteitis and osteomyelitis has two priorities: (a) Eradication of the infection; (b) Reconstruction of bone and soft tissue. Surgical treatment with resection of the affected bone segments and soft tissue, followed by reconstructive methods continues to be the main basic therapy, and is supported by local and systemic antibiotics and adjuvant methods such as hyperbaric oxygen. This article provides an overview of the diagnostic features and different surgical procedures as well as the current literature in order to reach the above named goals

    Study of coupled states for the (4s^{2})^{1}S + (4s4p)^{3}P asymptote of Ca_{2}

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    The coupled states A^{1}\Sigma_{u}^{+} (^{1}D +}1}S), c^{3}\Pi_{u} (^{3}P + ^{1}S) and a^{3}\Sigma_{u}^{+} (^{3}P +}1}S) of the calcium dimer are investigated in a laser induced fluorescence experiment combined with high-resolution Fourier-transform spectroscopy. A global deperturbation analysis of the observed levels, considering a model, which is complete within the subspace of relevant neighboring states, is performed using the Fourier Grid Hamiltonian method. We determine the potential energy curve of the A^{1}\Sigma_{u}^{+} and c^{3}\Pi_{u} states and the strengths of the couplings between them. The c^{3}\Pi_{u} and \as states are of particular importance for the description of collisional processes between calcium atoms in the ground state ^{1}S_{0} and excited state ^{3}P_{1} applied in studies for establishing an optical frequency standard with Ca.Comment: 15 pages, 12 figure

    Preservation of the shoulder joint by the use of a hybrid-spacer after septic loosening of a reversed total shoulder joint arthroplasty: a case report

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    Infections of a total joint replacement (TJR) of the shoulder are rare complications. After revision surgery, the incidence rises dramatically. If infection occurs, it leads to a loss of function and may be devastating to the joint. Treatment options range from single- to multiple-staged revision programs, permanent resection arthroplasty or exarticulation. In this case, a reversed shoulder endoprosthesis, which was implanted after multiple revisions of a TJR due to a posttraumatic omarthrosis and rotator cuff insufficiency, got infected. A hybrid-spacer, made of a humeral nail and a custom-made PMMA spacer forming the humeral head, was used during the revision program. After two operations, clinical and paraclinical signs turned back to normal. The patient felt well and was satisfied with the result of the therapy. The hybrid-spacer was then left in situ as a definitive solution with a satisfying range of motion. This case report shows that a hybrid-spacer can be helpful in the treatment of an infected shoulder TJR

    The potential of the ground state of NaRb

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    The X1Σ+^{1}\Sigma ^{+} state of NaRb was studied by Fourier transform spectroscopy. An accurate potential energy curve was derived from more than 8800 transitions in isotopomers 23^{23}Na85^{85}Rb and 23^{23}Na87^{87}Rb. This potential reproduces the experimental observations within their uncertainties of 0.003 \rcm to 0.007 \rcm. The outer classical turning point of the last observed energy level (v=76v''=76, J=27J''=27) lies at 12.4\approx 12.4 \AA, leading to a energy of 4.5 \rcm below the ground state asymptote.Comment: 8 pages, 6 figures and 2 table

    Radio frequency association of heteronuclear Feshbach molecules

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    We present a detailed analysis of the production efficiency of weakly bound heteronuclear KRb-Feshbach molecules using radio frequency association in a harmonic trap. The efficiency was measured in a wide range of temperatures, binding energies and radio frequencies. A comprehensive analytical model is presented, explaining the observed asymmetric spectra and achieving good quantitative agreement with the measured production rates. This model provides a deep understanding of the molecule association process and paves the way for future experiments which rely on Feshbach molecules e.g. for the production of deeply bound molecules.Comment: 5 pages, 4 figure

    Decadal assessment of sperm whale site-specific abundance trends in the northern Gulf of Mexico using passive acoustic data

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Li, K., Sidorovskaia, N. A., Guilment, T., Tang, T., & Tiemann, C. O. Decadal assessment of sperm whale site-specific abundance trends in the northern Gulf of Mexico using passive acoustic data. Journal of Marine Science and Engineering, 9(5), (2021): 454, https://doi.org/10.3390/jmse9050454.Passive acoustic monitoring has been successfully used to study deep-diving marine mammal populations. To assess regional population trends of sperm whales in the northern Gulf of Mexico (GoM), including impacts of the Deepwater Horizon platform oil spill in 2010, the Littoral Acoustic Demonstration Center-Gulf Ecological Monitoring and Modeling (LADC-GEMM) consortium collected broadband acoustic data in the Mississippi Valley/Canyon area between 2007 and 2017 using bottom-anchored moorings. These data allow the inference of short-term and long-term variations in site-specific abundances of sperm whales derived from their acoustic activity. A comparison is made between the abundances of sperm whales at specific sites in different years before and after the oil spill by estimating the regional abundance density. The results show that sperm whales were present in the region throughout the entire monitoring period. A habitat preference shift was observed for sperm whales after the 2010 oil spill with higher activities at sites farther away from the spill site. A comparison of the 2007 and 2015 results shows that the overall regional abundance of sperm whales did not recover to pre-spill levels. The results indicate that long-term spatially distributed acoustic monitoring is critical in characterizing sperm whale population changes and in understanding how environmental stressors impact regional abundances and the habitat use of sperm whales.This research was made possible by the 2015–2019 consortium grant from The Gulf of Mexico Research Initiative

    The coupling of the X1Σ+^{1}\Sigma ^{+} and a3Σ+^{3}\Sigma ^{+} states of KRb

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    A comprehensive study of the electronic states at the 4s+5s asymptote in KRb is presented. Abundant spectroscopic data on the \astate state were collected by Fourier-transform spectroscopy which allow to determine an accurate experimental potential energy curve up to 14.8 \AA . The existing data set (C. Amiot et al. J. Chem. Phys. 112, 7068 (2000)) on the ground state \Xstate was extended by several additional levels lying close to the atomic asymptote. In a coupled channels fitting routine complete molecular potentials for both electronic states were fitted. Along with the line frequencies of the molecular transitions, recently published positions of Feshbach resonances in 40^{40}K and 87^{87}Rb mixtures (F. Ferlaino et al. Phys. Rev. A 74, 039903 (2006)) were included in the fit. This makes the derived potential curves capable for an accurate description of observed cold collision features so far. Predictions of scattering lengths and Feshbach resonances in other isotopic combinations are reported.Comment: 14 pages, 5 figure

    Strategies for the analysis of osteitic bone defects at the diaphysis of long bones

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    Septic diseases of the bone and the immediate surrounding soft tissue, i.e., osteitis, belong to the most alarming findings in recent traumatology and orthopedic surgery. The paramount goal of this therapy is to preserve the stable weight-bearing bones while maintaining a correct axis and proper working muscles and joints, in order to avoid permanent disability in the patient. “State-of-the-art” therapy of osteitis/osteomyelitis therapy has two priorities: eradication of the infection and reconstruction of bone and soft tissue. Surgical treatment of the affected bone segments and soft tissue, followed by reconstructive methods, continues to be the main basic therapy. It is often extremely difficult to decide whether the affected bone segment has to be resected, or whether bone continuity can be preserved. The following paper provides strategies and guidance to help guide decisions in this complex and challenging area
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