Predictors for Readmission up to 1 Year Following Hip Fracture

Background: At Altnagelvin, a district general hospital in Northern Ireland, we have observed that a significant number of hip fracture admissions are later readmitted for treatment of other medical conditions. These readmissions place increasing stress on the already significant burden that orthopedic trauma poses on national health services. Objectives: The aim of this study was to review a series of consecutive patients managed at our unit at least 1 year prior to the onset of the study. Also, we aimed to identify predictors for raised admission rates following treatment for hip fracture. Patients and Methods: We reviewed a prospective fracture database and online patient note system for patient details, past medical history, discharge destination and routine blood tests for any factors that may influence readmission rates up to 1 year. Data were analyzed using SPSS software. Results: Over 2 years, 451 patients were reviewed and 23 were managed conservatively. There was a 1-year readmission rate of 21%. Most readmission diagnoses were medical including bronchopneumonia, falls, urosepsis, cardiac exacerbations and stroke. Prolonged length of stay and discharge to a residential, fold or nursing home were found to increase readmission rate. Readmission diagnoses closely reflected the perioperative diagnoses that prolonged length of stay. Increased odds radio and risk of readmission were also found with female gender, surgery with a cephalomedullary nail, hip hemiarthroplasty or total hip replacement, time to surgery 2 g/dL and also if a blood transfusion was received. Conclusions: Our results indicate that hip fracture treatment begins at acute fracture clerk in, with consideration of comorbid status and ultimate discharge planning remaining significant predictors for morbidity and subsequent readmission

Is there evidence for export-led adoption of ISO 14001? A review of the literature using meta-regression

Does the export orientation of a firm affect the likelihood that it adopts an environmental management certification? We use meta-regression methods to analyze systematically the corpus of published research on export-led adoption of the largest and most prominent certification, ISO 14001. We show that the explanatory variables authors choose to include in their models reflect the tenets of stakeholder and institutional theories. We also find that the literature suffers from substantial publication bias but that, once this is accounted for appropriately, a genuine effect remains. The evidence from 20 years of published studies taken as a whole is that export does incentivize the adoption of the standard as often hypothesized by proponents of voluntary approaches and self-regulation

Non-equilibrium phase behavior and friction of confined molecular films under shear: a non-equilibrium molecular dynamics study

The phase behavior of a confined liquid at high pressure and shear rate, such as is found in elastohydrodynamic lubrication, can influence the traction characteristics in machine operation. Generic aspects of this behavior are investigated here using Non-equilibrium Molecular Dynamics (NEMD) simulations of confined Lennard-Jones (LJ) films under load with a recently proposed wall-driven shearing method without wall atom tethering [C. Gattinoni et al., Phys. Rev. E 90, 043302 (2014)]. The focus is on thick films in which the nonequilibrium phases formed in the confined region impact on the traction properties. The nonequilibrium phase and tribological diagrams are mapped out in detail as a function of load, wall sliding speed, and atomic scale surface roughness, which is shown can have a significant effect. The transition between these phases is typically not sharp as the external conditions are varied. The magnitude of the friction coefficient depends strongly on the nonequilibrium phase adopted by the confined region of molecules, and in general does not follow the classical friction relations between macroscopic bodies, e.g., the frictional force can decrease with increasing load in the Plug-Slip (PS) region of the phase diagram owing to structural changes induced in the confined film. The friction coefficient can be extremely low (∼0.01) in the PS region as a result of incommensurate alignment between a (100) face-centered cubic wall plane and reconstructed (111) layers of the confined region near the wall. It is possible to exploit hysteresis to retain low friction PS states well into the central localization high wall speed region of the phase diagram. Stick-slip behavior due to periodic in-plane melting of layers in the confined region and subsequent annealing is observed at low wall speeds and moderate external loads. At intermediate wall speeds and pressure values (at least) the friction coefficient decreases with increasing well depth of the LJ potential between the wall atoms, but increases when the attractive part of the potential between wall atoms and confined molecules is made larger

Improving thermal and electrical efficiency in photovoltaic thermal systems for sustainable cooling system integration

Research into photovoltaic thermal systems is important in solar technologies as photovoltaic thermal systems are designed to produce both electrical and thermal energy, this can lead to improved performance of the overall system. The performance of photovoltaic thermal systems is based on several factors that include photovoltaic thermal materials, design, ambient temperature, inlet and outlet fluid temperature and photovoltaic cell temperature. The aim of this study is to investigate the effect of photovoltaic thermal outlet water temperatures and solar cell temperature on both electrical and thermal efficiency for different range of inlet water temperature. To achieve this, a mathematical model of a photovoltaic thermal system was developed to calculate the anticipated system performance. The factors that affect the efficiency of photovoltaic thermal collectors were discussed and the outlet fluid temperature from the photovoltaic thermal is investigated in order to reach the highest overall efficiency for the solar cooling system. An average thermal and electrical efficiency of 65% and 13.7%, respectively, was achieved and the photovoltaic thermal mathematical model was validated with experimental data from literature

Continuum-particle hybrid coupling for mass, momentum and energy transfers in unsteady fluid flow

The aim of hybrid methods in simulations is to communicate regions with disparate time and length scales. Here, a fluid described at the atomistic level within an inner region P is coupled to an outer region C described by continuum fluid dynamics. The matching of both descriptions of matter is made across an overlapping region and, in general, consists of a two-way coupling scheme (C->P and P->C) which conveys mass, momentum and energy fluxes. The contribution of the hybrid scheme hereby presented is two-fold: first it treats unsteady flows and, more importantly, it handles energy exchange between both C and P regions. The implementation of the C->P coupling is tested here using steady and unsteady flows with different rates of mass, momentum and energy exchange. In particular, relaxing flows described by linear hydrodynamics (transversal and longitudinal waves) are most enlightening as they comprise the whole set of hydrodynamic modes. Applying the hybrid coupling scheme after the onset of an initial perturbation, the cell-averaged Fourier components of the flow variables in the P region (velocity, density, internal energy, temperature and pressure) evolve in excellent agreement with the hydrodynamic trends. It is also shown that the scheme preserves the correct rate of entropy production. We discuss some general requirements on the coarse-grained length and time scales arising from both the characteristic microscopic and hydrodynamic scales.Comment: LaTex, 12 pages, 9 figure

Impact of excess NOx emissions from diesel cars on air quality, public health and eutrophication in Europe

Diesel cars have been emitting four to seven times more NOx in on-road driving than in type approval tests. These ‘excess emissions’ are a consequence of deliberate design of the vehicle’s after-treatment system, as investigations during the ‘Dieselgate’ scandal have revealed. Here we calculate health and environmental impacts of these excess NOx emissions in all European countries for the year 2013. We use national emissions reported officially under the UNECE Convention for Long-range Transport of Atmospheric Pollutants and employ the EMEP MSC-W Chemistry Transport Model and the GAINS Integrated Assessment Model to determine atmospheric concentrations and resulting impacts. We compare with impacts from hypothetical emissions where light duty diesel vehicles are assumed to emit only as much as their respective type approval limit value or as little as petrol cars of the same age. Excess NO2 concentrations can also have direct health impacts, but these overlap with the impacts from particulate matter (PM) and are not included here. We estimate that almost 10 000 premature deaths from PM2.5 and ozone in the adult population (age >30 years) can be attributed to the NOx emissions from diesel cars and light commercial vehicles in EU28 plus Norway and Switzerland in 2013. About 50% of these could have been avoided if diesel limits had been achieved also in on-road driving; and had diesel cars emitted as little NOx as petrol cars, 80% of these premature deaths could have been avoided. Ecosystem eutrophication impacts (critical load exceedances) from the same diesel vehicles would also have been reduced at similar rates as for the health effects

An Optical Readout TPC (O-TPC) for Studies in Nuclear Astrophysics With Gamma-Ray Beams at HIgS

We report on the construction, tests, calibrations and commissioning of an Optical Readout Time Projection Chamber (O-TPC) detector operating with a CO2(80%) + N2(20%) gas mixture at 100 and 150 Torr. It was designed to measure the cross sections of several key nuclear reactions involved in stellar evolution. In particular, a study of the rate of formation of oxygen and carbon during the process of helium burning will be performed by exposing the chamber gas to intense nearly mono-energetic gamma-ray beams at the High Intensity Gamma Source (HIgS) facility. The O-TPC has a sensitive target-drift volume of 30x30x21 cm^3. Ionization electrons drift towards a double parallel grid avalanche multiplier, yielding charge multiplication and light emission. Avalanche induced photons from N2 emission are collected, intensified and recorded with a Charge Coupled Device (CCD) camera, providing two-dimensional track images. The event's time projection (third coordinate) and the deposited energy are recorded by photomultipliers and by the TPC charge-signal, respectively. A dedicated VME-based data acquisition system and associated data analysis tools were developed to record and analyze these data. The O-TPC has been tested and calibrated with 3.183 MeV alpha-particles emitted by a 148Gd source placed within its volume with a measured energy resolution of 3.0%. Tracks of alpha and 12C particles from the dissociation of 16O and of three alpha-particles from the dissociation of 12C have been measured during initial in-beam test experiments performed at the HIgS facility at Duke University. The full detection system and its performance are described and the results of the preliminary in-beam test experiments are reported.Comment: Supported by the Richard F. Goodman Yale-Weizmann Exchange Program, ACWIS, NY, and USDOE grant Numbers: DE-FG02-94ER40870 and DE-FG02-97ER4103

fMRI evidence of ‘mirror’ responses to geometric shapes

Mirror neurons may be a genetic adaptation for social interaction [1]. Alternatively, the associative hypothesis [2], [3] proposes that the development of mirror neurons is driven by sensorimotor learning, and that, given suitable experience, mirror neurons will respond to any stimulus. This hypothesis was tested using fMRI adaptation to index populations of cells with mirror properties. After sensorimotor training, where geometric shapes were paired with hand actions, BOLD response was measured while human participants experienced runs of events in which shape observation alternated with action execution or observation. Adaptation from shapes to action execution, and critically, observation, occurred in ventral premotor cortex (PMv) and inferior parietal lobule (IPL). Adaptation from shapes to execution indicates that neuronal populations responding to the shapes had motor properties, while adaptation to observation demonstrates that these populations had mirror properties. These results indicate that sensorimotor training induced populations of cells with mirror properties in PMv and IPL to respond to the observation of arbitrary shapes. They suggest that the mirror system has not been shaped by evolution to respond in a mirror fashion to biological actions; instead, its development is mediated by stimulus-general processes of learning within a system adapted for visuomotor control

Control-volume representation of molecular dynamics

A Molecular Dynamics (MD) parallel to the Control Volume (CV) formulation of fluid mechanics is developed by integrating the formulas of Irving and Kirkwood, J. Chem. Phys. 18, 817 (1950) over a finite cubic volume of molecular dimensions. The Lagrangian molecular system is expressed in terms of an Eulerian CV, which yields an equivalent to Reynolds' Transport Theorem for the discrete system. This approach casts the dynamics of the molecular system into a form that can be readily compared to the continuum equations. The MD equations of motion are reinterpreted in terms of a Lagrangian-to-Control-Volume (\CV) conversion function $\vartheta_{i}$, for each molecule $i$. The \CV function and its spatial derivatives are used to express fluxes and relevant forces across the control surfaces. The relationship between the local pressures computed using the Volume Average (VA, Lutsko, J. Appl. Phys 64, 1152 (1988)) techniques and the Method of Planes (MOP, Todd et al, Phys. Rev. E 52, 1627 (1995)) emerges naturally from the treatment. Numerical experiments using the MD CV method are reported for equilibrium and non-equilibrium (start-up Couette flow) model liquids, which demonstrate the advantages of the formulation. The CV formulation of the MD is shown to be exactly conservative, and is therefore ideally suited to obtain macroscopic properties from a discrete system.Comment: 19 pages, 15 figure

A Framework to Estimate the Potential and Costs for the Control of Fine Particulate Emissions in Europe

This paper presents a methodology for estimating primary PM emissions in Europe and the costs involved to reduce these emissions from the various sources in the European countries. The framework developed is compatible with existing approaches to estimate emissions and costs for SO2, NOx, NH3 and VOC in the RAINS model. Emissions of PM are released from a large variety of sources with significant technical and economic differences. The emission characteristic of the sources is also strongly influenced by country-specific conditions. The method applied considers the crucial parameters and allows sectoral and regional variation. The emissions of particulate matter (PM) in the RAINS model are calculated for three different size classes (i) fine fraction (PM2.5), (ii) coarse fraction (PM10 - PM2.5) and (iii) large particles (PM_>10 mu m). A methodology has been developed to estimate emission control costs of standard technologies under the specific conditions characteristic for the various European countries. Based on the assumption of the general availability of control technologies with equal technical properties and costs, a number of country-specific circumstances (level of technological advancement, installation size distribution, labor costs, etc.) are used to estimate the costs for the actual operation of pollution control equipment. Based on the developed methodology, a first estimate of the PM emissions in Europe was derived for the years 1990, 1995 and 2010. This estimate must be considered as preliminary, since many of the emission factors need revision and update with additional information. The projections for the year 2010 assume full implementation of the current legislation on emission controls, e.g., the EURO-IV emission standards resulting from the Auto Oil process for mobile sources, and regulations relating to the large combustion plant directive of the European Union. Major reductions in PM emissions occurred between 1990 and 1995, mainly because of the economic restructuring in Eastern Europe where many old coal power stations were retired. Between 1990 and 1995, TSP emissions declined by 41 percent; for 2010 a decline of 58 percent is projected. Emission reductions are most efficient for larger particles; for 2010, PM10 is calculated to decline by 56 percent, and PM2.5 by 48 percent. Consequently, fine fraction (PM2.5) will be relatively more important in the future (38 percent of TSP in 2010) compared to 31 percent of TSP in 1990. In 1990, combustion in energy industries, small non-industrial combustion sources, production processes and road transport contributed about 20 percent each to total TSP emissions in the EU-15. In the non-EU countries, small sources and power plants were responsible for more than 30 percent each, while road transport contributed only three percent of TSP. In those countries, small sources (domestic coal and wood combustion) are expected to increase their share to 45 percent in 2010, while in the EU-15 mobile sources will become the most important source category for TSP emissions (45 percent). For PM2.5, mobile sources were the largest contributor in 1990 in the EU-15 countries (31 percent). This share is expected to decline slightly by 2010 (28 percent) due to the strict regulations that were recently introduced. In the non-EU countries, industrial production processes were the largest source of PM2.5 emissions (36 percent), while in 2010 small combustion sources in the domestic sector will dominate (38 percent). The present implementation (version 1.03) of the RAINS PM module on the Internet (www.iiasa.ac.at/~rains/PM/pm-home.html) provides free access to the input data and results to facilitate interaction with national experts