2,009 research outputs found

    Migrated Avalon Veno-Venous Extracorporeal Membrane Oxygenation Cannula: How to Adjust Without Interruption of Flow.

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    The Avalon dual lumen cannula is presently the cannula of choice for veno-venous extracorporeal membrane oxygenation (VV-ECMO) via right internal jugular cannulation. This cannula establishes VV-ECMO with a single cannulation; however, it requires appropriate positioning to gain adequate oxygenation. Malposition of this cannula can cause inadequate ECMO flow, hypoxia, and structural injury. We have experienced two cases of migration: one into the hepatic vein and the other into the right ventricle. The former was repositioned using echocardiographic guidance without using a guidewire. The latter was repositioned using a guidewire from the femoral vein under fluoroscopy, without antegrade wire placement into the Avalon cannula, discontinuation of ECMO, or bleeding

    Current directions in fisheries management policy: A perspective on co-management and its application to South African fisheries

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    There is much current interest in fisheries management policy which centres around the introduction of rights-based management systems, the devolution of control from central regulatory authorities, and the conceptof co-management. In order to address the complexity of the last of these, key principles of co-management arrangements need to be identified. In the process of establishing these arrangements, rules and rights are redefined and new institutions are created for the management of common pool resources, where exclusion is costly and every resource harvester subtracts value from the harvest of the others. A preliminary analysis of co-management arrangements is presented that postulates the factors most important for their establishment, reference being made to the applicability of co-management in South African fisheries. As with other studies on management of common property resources, it is concluded that the definition of boundaries, both resource and human, are critical to the process. In addition, the rules governing participation and the allocation of costs and benefits need to be mutually agreed upon by all participants, and most importantly well defined, if successful arrangements are to be established

    Fine and gross motor ability in males with ADHD

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    In this study, both fine and gross motor ability of males with attention-deficit-hyperactivity disorder (ADHD) were compared with a group of control children. Three groups of males with the following ADHD subtypes: predominantly inattentive (ADHD-PI; n=50), hyperactive/impulsive (ADHD-HI; n=16), or combined (ADHD-C; n=38) were compared with 39 control males. Mean ages for the control group were 10 years 4 months (SD 1 year 4 months, range 7 years 8 months to 12 years 11 months); for the ADHD-PI group, 10 years (SD 1 year 2 months, range 7 years 10 months to 13 years); for the ADHD-HI group, 9 years 11 months (SD 1 year 2 months), range 7 years 11 months to 12 years 6 months); and for the ADHD-C group 10 years 2 months (SD1 year 4 months, range 8 to 13 years). The Australian Disruptive Behaviours Scale and Connor's Parent Rating Scale-Revised were used to assess ADHD symptomatology. Verbal IQ was estimated using two verbal subtests of the Wechsler Intelligence Scale for Children (MABC) and the Purdue Pegboard test. Findings demonstrated that the children with ADHD had significantly poorer movement ability than control children. A high percentage of these children displayed movement difficulties consistent with developmental coordination disorder (DCD). In addition, the current study found that the type and degree of movement difficulty differed between subtypes. The Total Impairment score, as derived from the MABC, was less severe for the ADHD-HI group than the two ADHD groups, but more severe than for the control group. Males with ADHD-PI and ADHD-C had significantly poorer fine motor ability (p<0.001) than control males, whereas the ADHD-HI group did not differ significantly on fine motor ability but were significantly better than children categorized with both ADHD and DCD, it was argued that poorer fine motor ability found in children with ADHD could not be attributed to deficits in attention and concentration, but rather to factors relating to their motor ability

    Management considerations of massive hemoptysis while on extracorporeal membrane oxygenation.

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    BACKGROUND: Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is a life-saving procedure in patients with both respiratory and cardiac failure. Bleeding complications are common since patients must be maintained on anticoagulation. Massive hemoptysis is a rare complication of ECMO; however, it may result in death if not managed thoughtfully and expeditiously. METHODS: A retrospective chart review was performed of consecutive ECMO patients from 7/2010-8/2014 to identify episodes of massive hemoptysis. The management of and the outcomes in these patients were studied. Massive hemoptysis was defined as an inability to control bleeding (\u3e300 mL/day) from the endotracheal tube with conventional maneuvers, such as bronchoscopy with cold saline lavage, diluted epinephrine lavage and selective lung isolation. All of these episodes necessitated disconnecting the ventilator tubing and clamping the endotracheal tube, causing full airway tamponade. RESULTS: During the period of review, we identified 118 patients on ECMO and 3 (2.5%) patients had the complication of massive hemoptysis. One case was directly related to pulmonary catheter migration and the other two were spontaneous bleeding events that were propagated by antiplatelet agents. All three patients underwent bronchial artery embolization in the interventional radiology suite. Anticoagulation was held during the period of massive hemoptysis without any embolic complications. There was no recurrent bleed after appropriate intervention. All three patients were successfully separated from ECMO. CONCLUSIONS: Bleeding complications remain a major issue in patients on ECMO. Disconnection of the ventilator and clamping the endotracheal tube with full respiratory and cardiac support by V-A ECMO is safe. Early involvement of interventional radiology to embolize any potential sources of the bleed can prevent re-hemoptysis and enable continued cardiac and respiratory recovery

    Determination of characteristic muon precession and relaxation signals in FeAs and FeAs2, possible impurity phases in pnictide superconductors

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    We report muon-spin relaxation measurements of highly homogeneous samples of FeAs and FeAs2, both previously found as impurity phases in some samples of recently synthesized pnictide superconductors. We observe well defined muon precession in the FeAs sample with two precession frequencies of 38.2(3) and 22.7(9) MHz at 7.5 K, with the majority of the amplitude corresponding to the lower frequency component. In FeAs2 we confirm previous measurements showing that no long-ranged magnetic order occurs above 2 K and measure the muon spin relaxation rate, which increases on cooling. Our results exclude the possibility that previous muon-spin relaxation measurements of pnictide superconductors have been measuring the effect of these possible impurities.Comment: 4 pages, 3 figures, corrected Figure

    Charge carrier localization induced by excess Fe in the Fe1+y(Te,Se) superconductor system

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    We have investigated the effect of Fe nonstoichiometry on properties of the Fe1+y(Te, Se) superconductor system by means of resistivity, Hall coefficient, magnetic susceptibility, and specific heat measurements. We find that the excess Fe at interstitial sites of the (Te, Se) layers not only suppresses superconductivity, but also results in a weakly localized electronic state. We argue that these effects originate from the magnetic coupling between the excess Fe and the adjacent Fe square planar sheets, which favors a short-range magnetic order.Comment: 15 pages, 6 figures accepted for publication in PR

    Superconductivity up to 30 K in the vicinity of quantum critical point in BaFe2_{2}(As1−x_{1-x}Px_{x})2_{2}

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    We report bulk superconductivity induced by an isovalent doping of phosphorus in BaFe2_{2}(As1−x_{1-x}Px_{x})2_{2}. The P-for-As substitution results in shrinkage of lattice, especially for the FeAs block layers. The resistivity anomaly associated with the spin-density-wave (SDW) transition in the undoped compound is gradually suppressed by the P doping. Superconductivity with the maximum TcT_c of 30 K emerges at xx=0.32, coinciding with a magnetic quantum critical point (QCP) which is evidenced by the disappearance of SDW order and the linear temperature-dependent resistivity in the normal state. The TcT_c values were found to decrease with further P doping, and no superconductivity was observed down to 2 K for x≄x\geq 0.77. The appearance of superconductivity in the vicinity of QCP hints to the superconductivity mechanism in iron-based arsenides.Comment: 9 pages, 4 figures; more data; to appear in Journal of Physics: Condensed Matte

    Enhancement of Superfluid Stiffness, Suppression of Superconducting T_c and Field-induced Magnetism in the Pnictide Superconductor LiFeAs

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    Transverse-field muon-spin rotation measurements performed on two samples of LiFeAs demonstrate that the superfluid stiffness of the superconducting condensate in relation to its superconducting transition temperature is enhanced compared to other pnictide superconductors. Evidence is seen for a field-induced magnetic state in a sample with a significantly suppressed superconducting transition temperature. The results in this system highlight the role of direct Fe-Fe interactions in frustrating pairing mediated by antiferromagnetic fluctuations and suggest that, in common with other pnictide superconductors, the system is close to a magnetic instability.Comment: 4 pages, 5 figure

    Magnetic fluctuations and spin freezing in nonsuperconducting LiFeAs derivatives

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    We present detailed magnetometry and muon-spin rotation data on polycrystalline samples of overdoped, nonsuperconducting LiFe1−xNixAs (x = 0.1,0.2) and Li1−yFe1+yAs (0 y 0.04) as well as superconducting LiFeAs.While LiFe1−xNixAs exhibits weak antiferromagnetic fluctuations down to 1.5 K,Li1−yFe1+yAs samples, which have a much smaller deviation from the 1 : 1 : 1 stoichiometry, show a crossover from ferromagnetic to antiferromagnetic fluctuations on cooling and a freezing of dynamically fluctuating moments at low temperatures. We do not find any signatures of time-reversal symmetry breaking in stoichiometric LiFeAs that would support recent predictions of triplet pairing

    Whistler mode startup in the Michigan Mirror Machine

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    Results of investigations of whistler mode ECRH plasma startup in the Michigan Mirror Machine are presented. Electron‐velocity‐distribution and plasma‐spatial‐distribution time evolution are characterized by measurements from axially and radially moveable Langmuir probes, an endloss current detector, an electron cyclotron emission radiometer, a foil‐filtered X‐ray detector, and a diamagnetic loop at the mirror midplane. Measurements of the buildup of both electron density and perpendicular pressure (nkT⟂) are compared to predictions from various numerical models. Both modeling and data suggest the creation of a highly anisotropic electron velocity distribution function with a ‘‘sloshing electron’’ axial density profile.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87352/2/204_1.pd
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