Vascular Complications of Allograft Nephrectomy

AbstractObjectivesTo identify risk factors that predisposes patients to vascular complications from allograft nephrectomy and to determine the safe management of this group of patients.DesignThis is a retrospective review of 1543 renal transplants performed in our institution between January 1990 and January 2002.Patients and methodsDuring this period, 161 (10.4%) transplant nephrectomies were performed, of which we identified nine patients (5.6%) who sustained significant vascular complications.ResultsSeven patients required ligation of external iliac artery for control of haemorrhage. Immediate vascular reconstructions (femoral–femoral cross-over bypass in two cases and one vein patch to an external iliac artery defect) were performed in three patients. Two patients had endovascular stenting of their external iliac artery pseudoaneurysm. No patient suffered limb loss. However, three patients died—two died from overwhelming sepsis and one patient died of an intra-cerebral haemorrhage.ConclusionsWhile vascular complications associated with transplant nephrectomy are relatively rare, they are associated with a significantly poor outcome. Immediate attempts to reconstruct the vascular supply to the lower limb are associated with a high complication rate. We advocate that where possible, vascular reconstruction should be deferred and that external iliac artery ligation can be performed safely with surprisingly low limb ischaemia rate

Facial masculinity is related to perceived age, but not perceived health

Variation in women's preferences for male facial masculinity may reflect variation in attraction to immunocompetence or to maturity. This paper reports two studies on (a) the interrelationships between women's preferences for masculinity, apparent health, and age in male faces and (b) the extent to which manipulating each of these characteristics affects women's attributions of the remaining characteristics. Both studies were carried out with a large sample of the general public (Studies 1a and 2a) and independently in a laboratory environment with smaller undergraduate samples (Studies 1b and 2b). In both samples, masculinity and age preferences were positively related, and masculinity preferences were not associated with preferences for apparent health. There was also a positive relationship between perceived age and perceived masculinity in both samples, but evidence for a link between perceptions of masculinity and health was equivocal. Collectively, these findings suggest that variation in women's preferences for masculine proportions in male faces reflect variation in attraction to male age and do not support a strict immunocompetence explanation of preferences for facial masculinity

A mobile mapping system for hazardous facilities

The Mobile Mapping System (MMS) is a completely self-contained vehicle with omnidirectional capability and extremely good odometry, capable of operation up to 12 hours between battery charges. The platform itself is based on a dual differential drive system with a compliant linkage between the two drive systems. This compliant linkage allows for low-level controller errors to be absorbed by the system and their navigational effects to be compensated for, yielding an extremely accurate navigational capability. Vehicle design also allows for a considerable payload (250 lb) and a large surface area for auxiliary equipment mounting (2 by 6 ft). The vehicle supports remote operation by reading commands and writing replies through its serial communications port. Use of a radio-ethernet and a radio-video channel allow for remote video and communications links to be maintained with the vehicle in many remote operation environments. The MMS uses a structured light system to quickly acquire coarse range images of the environment and a coherent laser radar (CLR) to acquire finer resolution range images. The coherent laser radar can also be used to determine platform position and orientation to millimeter accuracies if targets of known. Sensor range image data as well as video are off loaded to a remote computer for postprocessing, display, and archiving. Diagrams and images below include an image of the MMS vehicle before addition of sensors, diagram of vehicle with sensors, and computer system connections

Wigner crystal in snaked nanochannels

We study properties of Wigner crystal in snaked nanochannels and show that they are characterized by conducting sliding phase at low charge densities and insulating pinned phase emerging above a certain critical charge density. The transition between these phases has a devil's staircase structure typical for the Aubry transition in dynamical maps and the Frenkel-Kontorova model. We discuss implications of this phenomenon for charge density waves in quasi-one-dimensional organic conductors and for supercapacitors in nanopore materials.Comment: 4 pages, 6 figs, research at http://www.quantware.ups-tlse.f

Variable geometries of connection: Urban digital divides and the uses of Information Technology

This paper proposes a new way of conceptualising urban ‘digital divides’. It focuses on the ways in which Information and Communication Technologies (ICTs) unevenly affect the pace of life within the urban environment. Based on a detailed case study of how ICT s are being used in an affluent and a marginalised neighbourhood in Newcastle-upon-Tyne, the paper suggests that urban digital divides need to be understood as more than uneven patterns of access. They emerge in this work as more than the presence or absence of specific technological artefacts. Rather, it is argued that different styles and speeds of technologically mediated life now work to define urban socio-spatial inequalities. The paper distinguishes between two such key styles and speeds. First, the paper argues that affluent and professional groups now use new media technologies pervasively and continuously as the ‘background’ infrastructure to sustain privileged and intensely distanciated, but time-stressed, lifestyles. Second, more marginalised neighbourhoods tend to be characterised by instrumental and episodic ICT usage patterns which are often collectively organised through strong neighbourhood ties. For the former, mediated networks help orchestrate neighbourhood ties; for the latter it is those neighbourhood ties that enable online access

Keeping It Real: Revisiting a Real-Space Approach to Running Ensembles of Cosmological N-body Simulations

In setting up initial conditions for ensembles of cosmological N-body simulations there are, fundamentally, two choices: either maximizing the correspondence of the initial density field to the assumed fourier-space clustering or, instead, matching to real-space statistics and allowing the DC mode (i.e. overdensity) to vary from box to box as it would in the real universe. As a stringent test of both approaches, I perform ensembles of simulations using power law and a "powerlaw times a bump" model inspired by baryon acoustic oscillations (BAO), exploiting the self-similarity of these initial conditions to quantify the accuracy of the matter-matter two-point correlation results. The real-space method, which was originally proposed by Pen 1997 and implemented by Sirko 2005, performed well in producing the expected self-similar behavior and corroborated the non-linear evolution of the BAO feature observed in conventional simulations, even in the strongly-clustered regime (sigma8 >= 1). In revisiting the real-space method championed by Sirko 2005, it was also noticed that this earlier study overlooked an important integral constraint correction to the correlation function in results from the conventional approach that can be important in LambdaCDM simulations with Lbox == Lbox / 10. Rectifying this shows that the fourier space and real space methods are about equally accurate and efficient for modeling the evolution and growth of the correlation function, contrary to previous claims. An appendix provides a useful independent-of-epoch analytic formula for estimating the importance of the integral constraint bias on correlation function measurements in LambdaCDM simulations.Comment: 28 pages, 7 figures, substantial improvements throughou

Organic Superconductors: when correlations and magnetism walk in

This survey provides a brief account for the start of organic superconductivity motivated by the quest for high Tc superconductors and its development since the eighties'. Besides superconductivity found in 1D organics in 1980, progresses in this field of research have contributed to better understand the physics of low dimensional conductors highlighted by the wealth of new remarkable properties. Correlations conspire to govern the low temperature properties of the metallic phase. The contribution of antiferromagnetic fluctuations to the interchain Cooper pairing proposed by the theory is borne out by experimental investigations and supports supercondutivity emerging from a non Fermi liquid background. Quasi one dimensional organic superconductors can therefore be considered as simple prototype systems for the more complex high Tc materials.Comment: 41 pages, 21 figures to be published in Journal of Superconductivity and Novel Magnetis