2,824 research outputs found

    Our Relation To the People of Cuba and Porto Rico

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    Functional renormalization group study of an eight-band model for the iron arsenides

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    We investigate the superconducting pairing instabilities of eight-band models for the iron arsenides. Using a functional renormalization group treatment, we determine how the critical energy scale for superconductivity depends on the electronic band structure. Most importantly, if we vary the parameters from values corresponding to LaFeAsO to SmFeAsO, the pairing scale is strongly enhanced, in accordance with the experimental observation. We analyze the reasons for this trend and compare the results of the eight-band approach to those found using five-band models.Comment: 11 pages, 10 figure

    Comparison of outcomes following minimally invasive and open posterior cervical foraminotomy: description of minimally invasive technique and review of literature.

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    Although minimally invasive posterior cervical foraminotomy (MIS-PCF) is frequently employed in the treatment of cervical radiculopathy, there are very few studies directly comparing outcomes between MIS-PCF and open posterior cervical foraminotomy and between MIS-PCF and percutaneous endoscopic (full-endoscopic) posterior cervical foraminotomy (FE-PCF). This study includes a description of technique and systematic review of literature and analysis of clinical studies comparing outcomes between MIS-PCF and open posterior cervical foraminotomy and between MIS-PCF and FE-PCF. Six comparative studies, including one randomized controlled trial were included in analysis. Average operative time ranged from 60.5 to 171 minutes in the open group and 77.65 to 115 minutes in the MIS group. Mean intraoperative blood loss ranged from 43.5 to 246 cc in the open group and 42 to 138 cc in the MIS group. Average postoperative length of stay ranged from 58.6 to 304.8 hours in the open group and 20 to 273.6 hours in the MIS group. Two studies reported significantly increased VAS-N (Neck) scores postoperatively in patients undergoing open cervical foraminotomies, however both studies reported that the differences lost statistical significance with longer follow-up. There were no significant differences in complications or reoperations between open and MIS groups. One retrospective cohort study was included in analysis that compared MIS-PCF and FE-PCF. Postoperatively at 24 months, mean NDI and VAS-N were significantly lower after FE-PCF than MIS-PCF. There was no significant change in VAS-A (Arm) between the two groups. Direct comparative studies between MIS-PCF and open cervical foraminotomy are limited in number. Although, there is a significant heterogeneity in studies comparing open and MIS-PCF there appears to be a trend of decreased hospital length of stay and postoperative analgesic usage in the minimally invasive cohort

    Short- and Long-Term Complications of Free Anterolateral Thigh Flap Reconstructions: A Single-Centre Experience of 92 Consecutive Cases.

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    Background The anterolateral thigh (ALT) flap has been amongst the most versatile components of the reconstructive surgeon's armamentarium. The authors utilise these flaps for a variety of reconstructive procedures including lower limb reconstruction; postsarcoma excision; and open fractures. Few studies have discussed the extent of recipient site morbidity and subsequent revisional procedures. We will report our experience of the ALT flap in 92 consecutive reconstructions with focus on recipient site complications and revisional procedures. Methods Retrospective data collection was done from 92 patients who underwent ALT flap reconstruction-for various large soft tissue defects-at our unit at the Royal Free Hospital, London. We evaluated primary recipient site complications and the requirements for secondary operations after flap transfer. Results All flaps survived with the exception of 3 cases (97% survival rate) in which irreversible venous thrombosis was encountered. 16 of 92 patients (17%) required a second recipient site operation for the following: 7 patients experienced major recipient site complications that warranted early return to theatre and 9 patients required a secondary revision thinning procedure(s). 8 of the 16 patients (50%) requiring second operations had construction on their lower leg/ankle/feet (p value = 0.10). Conclusions Our data demonstrated effective use of the ALT flap in the management of soft tissue reconstructive surgery. Partial flap necrosis was the main complication at the recipient site. In future work, secondary thinning procedures, particularly at the ankle/foot, should be separated from flap-specific complications. Furthermore, we demonstrate tailoring ALT thickness can be performed safely without compromising flap viability

    Enhanced tropospheric BrO concentrations over the Antarctic sea ice belt in mid winter observed from MAX-DOAS observations on board the research vessel Polarstern

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    International audienceWe present Multi AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS) observations of tropospheric BrO carried out on board the German research vessel Polarstern during the Antarctic winter 2006. Polarstern entered the area of first year sea ice around Antarctica on 24 June 2006 and stayed within this area until 15 August 2006. For the period when the ship cruised inside the first year sea ice belt, enhanced BrO concentrations were almost continuously observed. One interesting exception appeared on 7 July 2006, when the sun elevation angle was 2 and/or HOBr is too slow to provide sufficient amounts of Br radicals. Before and after the period inside the first year sea ice belt, typically low BrO concentrations were observed. Our observations indicate that enhanced BrO concentrations around Antarctica exist about one month earlier than observed by satellite instruments. The small BrO concentrations over the open oceans indicate a short atmospheric lifetime of activated bromine without contact to areas of first year sea ice. From detailed radiative transfer simulations we find that MAX-DOAS observations are about one order of magnitude more sensitive to near-surface BrO than satellite observations. In contrast to satellite observations the MAX-DOAS sensitivity hardly decreases for large solar zenith angles and is almost independent from the ground albedo. Thus this technique is very well suited for observations in polar regions close to the solar terminator. Furthermore, combination of both techniques could yield additional information on the vertical distribution of BrO in the lower troposphere

    The Effect of Poststenotic Vessel Wall Compliance upon the Pulsus Tardus Phenomenon

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    Recent studies have investigated the detection of significant arterial stenoses through identification of the "pulsus tardus" phenomenon in Doppler waveforms obtained distal to the stenosis. The etiology of this phenomenon, however, has not yet been determined. Using an in vitro model based upon an electrical circuit analogy, the authors had as their objective to determine whether the compliance of the vessel wall immediately distal to a stenosis, in conjunction with the stenosis, is the cause of pulsus tardus. For a constant stenosis, it was found that the degree of pulsus tardus, as quantitated by the acceleration index, increased as the compliance of the poststenotic segment increased. It is concluded that pulsus tardus distal to an arterial stenosis is likely due to the compliance of the normally distensible artery, in conjunction with the stenosis. Pathological conditions that alter the compliance of the poststenotic segment may affect the degree of pulsus tardus, perhaps limiting its usefulness for upstream stenosis detection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68136/2/10.1177_000331979404500703.pd

    Tactile Gloves for Autonomous Grasping With the NASA/DARPA Robonaut

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    Tactile data from rugged gloves are providing the foundation for developing autonomous grasping skills for the NASA/DARPA Robonaut, a dexterous humanoid robot. These custom gloves compliment the human like dexterity available in the Robonaut hands. Multiple versions of the gloves are discussed, showing a progression in using advanced materials and construction techniques to enhance sensitivity and overall sensor coverage. The force data provided by the gloves can be used to improve dexterous, tool and power grasping primitives. Experiments with the latest gloves focus on the use of tools, specifically a power drill used to approximate an astronaut's torque tool
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