Optical characterization of high performance mirrors based on cavity ringdown time measurements with 6 degrees of freedom mirror positioning.

An instrument capable of measuring optical losses, transmission, and the radius of curvature of high reflectivity mirrors is presented. The measurement setup consists of two remote controlled hexapod systems with 6 degrees of freedom placed inside a vacuum enclosure. Mirror loss measurements are performed via the cavity ring-down time method using a linear resonant two-mirror Fabry-Perot cavity configuration. The use of high-precision positioning systems enables cavity loss mapping by transversely scanning the position of the cavity end mirror. Mirror surfaces of up to 30 mm in diameter can be scanned, and the cavity length can be tuned by 120 mm.

Stress responses to repeated exposure to a combined physical and social evaluative laboratory stressor in young healthy males.

Repeated exposure to homotypic laboratory psychosocial stressors typically instigates rapid habituation in hypothalamic-pituitary-adrenal (HPA) axis-mediated stress responses in humans. However, emerging evidence suggests the combination of physical stress and social evaluative threat may be sufficient to attenuate this response habituation. Neuroendocrine, cardiovascular and subjective stress responses following repeated exposure to a combined physical and social evaluative stress protocol were assessed to examine the habituation response dynamic in this context. The speech task of the Trier social stress test (TSST; Kirschbaum et al., 1993) and the socially evaluated cold pressor task (SECPT; Schwabe et al., 2008) were administered in a combined stressor protocol. Salivary cortisol, cardiovascular and subjective stress responses to a non-stress control and repeat stressor exposure separated by six weeks were examined in males (N=24) in a crossover manner. Stressor exposure resulted in significant elevations in all stress parameters. In contrast to the commonly reported habituation in cortisol response, a comparable post-stress response was demonstrated. Cortisol, heart rate and subjective stress responses were also characterised by a heightened response in anticipation to repeated stress exposure. Blood pressure responses were comparatively uniform across repeated exposures. Findings suggest a combined physical and social evaluative stressor is a potentially useful method for study designs that require repeated presentation of a homotypic stressor.

Opportunities and methodological challenges in EEG and MEG resting state functional brain network research.

Electroencephalogram (EEG) and magnetoencephalogram (MEG) recordings during resting state are increasingly used to study functional connectivity and network topology. Moreover, the number of different analysis approaches is expanding along with the rising interest in this research area. The comparison between studies can therefore be challenging and discussion is needed to underscore methodological opportunities and pitfalls in functional connectivity and network studies. In this overview we discuss methodological considerations throughout the analysis pipeline of recording and analyzing resting state EEG and MEG data, with a focus on functional connectivity and network analysis. We summarize current common practices with their advantages and disadvantages; provide practical tips, and suggestions for future research. Finally, we discuss how methodological choices in resting state research can affect the construction of functional networks. When taking advantage of current best practices and avoid the most obvious pitfalls, functional connectivity and network studies can be improved and enable a more accurate interpretation and comparison between studies.

Delay influences outcome after lower limb major amputation.

AIM: To investigate if a relationship exists between hospital waiting time to major amputation and outcome. METHOD: All patients undergoing major lower limb amputation in England between April 2002 and March 2006 were identified from the Hospital Episodes Statistics (HES) data. Amputations related to trauma or malignancy were excluded. The length of wait (LOW), from date of admission to date of major amputation was calculated. A two-level regression model was used to investigate if LOW had a significant effect on recovery time and in-hospital mortality. Results were adjusted for age, sex, Charlson score, Social Deprivation, mode of intervention (bypass/angioplasty/no intervention) and mode of admission (emergency/elective). RESULTS: 14,168 major amputations were identified. 12,884 (90.9%) had no intervention prior to amputation on that admission. Length of Wait (LOW) significantly prolonged recovery in men (Exponential Estimate 1.01 1.01-1.02 p < 0.0001) and women (EE 1.02 1.01-1.02 p < 0.0001) and increased in-hospital mortality in men (OR 1.02 1.02-1.03 p < 0.0001). Risk of in-hospital death increased by 2% for each day waited. CONCLUSION: Delays in decision making or in getting a patient into the operating theatre have a negative effect on patient outcome in terms of overall length of stay and mortality after major lower limb amputation.

Provider volume and long-term outcome after elective abdominal aortic aneurysm repair.

BACKGROUND: Robust risk-adjusted analyses have demonstrated that a reduction in perioperative mortality is associated with the repair of an abdominal aortic aneurysm (AAA) in centres with a high operative caseload (volume). However, the long-term impact of this volume-related effect on mortality remains unknown. METHODS: Demographic and clinical data were extracted from UK Hospital Episodes Statistics for patients undergoing elective repair of an infrarenal AAA from 1 April 2000 to 31 March 2005. The long-term mortality of this cohort was investigated through linkage to the UK Office for National Statistics (ONS) registry. Risk-adjusted survival was analysed using Cox proportional hazards modelling to identify the effect of hospital volume on long-term mortality. RESULTS: A total of 14 396 patients with mean age of 72 years, of whom 85.7 per cent were men, underwent elective repair of an infrarenal AAA in England. They were linked to follow-up using ONS data. Risk-adjusted analysis of all-cause mortality by Cox proportional hazards modelling demonstrated a significant effect of hospital volume across all quintiles up to 2 years (P = 0.013). Remodelling the data after excluding in-hospital mortality still demonstrated the significant effect of hospital volume on late outcome. CONCLUSION: There is a long-term benefit to patients who undergo elective AAA repair in a high-volume hospital.

Sustained low prevalence of meticillin-resistant Staphylococcus aureus upon admission to hospital in The Netherlands.

The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) carriage at hospital admission in The Netherlands was 0.03% in 1999-2000. The aim of the present study was to assess whether the prevalence of MRSA carriage in The Netherlands has changed over the last few years. In five Dutch hospitals, 6496 unique patients were screened for nasal S. aureus carriage at hospital admission by microbiological culture between 1 October 2005 and 7 June 2007. In total, 2036 of 6496 (31.3%) patients carried S. aureus in their nose, and seven of 6496 (0.11%) patients were nasal carriers of MRSA. Compared with 1999-2000, the prevalence of MRSA carriage in the Dutch population at hospital admission has increased more than three fold; however, this increase was not significant (P=0.06, Fisher's exact test). This prevalence is still among the lowest in the world, probably as a result of the stringent Dutch infection control policy, and the restrictive use of antibiotics in The Netherlands.

Trends and outcomes after surgical lower limb revascularization in England.

BACKGROUND: The aim was to analyse contemporary data on the number of surgical revascularization procedures performed each year in England, and their outcome. METHODS: Hospital Episode Statistics and Office for National Statistics data were used to quantify numbers and identify factors associated with outcome after all femoropopliteal and femorodistal bypass procedures performed between 2002 and 2006. Outcome measures were repeat bypass, major amputation, death and a composite measure. Single-level multivariable logistic regression modelling was used to quantify the effect of these variables on outcome. RESULTS: A total of 21,675 femoropopliteal and 3458 femorodistal bypass procedures were performed. Mean in-hospital mortality rates were 6·7 and 8·0 per cent respectively. One-year survival rates were 82·8 and 79·1 per cent; both increased over the study interval. The mean 1-year major amputation rate after femoropopliteal bypass was 10·4 per cent, which decreased significantly over the 5 years (P < 0·001); after distal bypass the rate of 20·8 per cent remained unchanged (P = 0·456). Diabetes mellitus and chronic kidney disease were significant predictors of adverse outcome for both procedures: odds ratio (OR) at 1 year 1·56 (95 per cent confidence interval 1·46 to 1·67; P < 0·001) and 2·15 (1·88 to 2·45; P < 0·001) respectively for femoropopliteal bypass. Previous femoral angioplasty was associated with an increased rate of major amputation 1 year after proximal bypass (OR 1·18, 1·05 to 1·33; P = 0·004). CONCLUSION: Although all mortality rates are improving, the major amputation rate remains high after femorodistal bypass. Adverse events occurred after 37·6 per cent of femoropopliteal and 49·7 per cent of femorodistal bypasses; diabetes and chronic renal failure were the main predictors of poor outcome.

Computerised Decision Support Systems for the management of freshwater radioecological emergencies: assessment of the state-of-the-art with respect to the experiences and needs of end-users.

Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS "integration" became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS.

Epidemiological study of lower limb amputation in England between 2003 and 2008.

BACKGROUND: The purpose of this study was to investigate the prevalence of lower extremity amputation in England, to establish the associated mortality, and to determine the relationship with diabetes mellitus and previous revascularization. METHODS: Data on all patients who had a lower extremity amputation between 2003 and 2008 were extracted from the Hospital Episode Statistics database. Risk adjustment and linear regression were used to compare the data. RESULTS: The major amputation rate was 5.1 per 100,000 population and did not change over the 5 years. The mortality rate for major leg amputation was 16.8 per cent (21.4 per cent for above-knee and 11.6 per cent for below-knee amputation); this decreased significantly over time (P < 0.001). There was a significant difference in amputation rate, mortality rate and the below-knee : above-knee amputation ratio between different areas of England (P < 0.001). Some 39.4 per cent of patients who underwent major amputation had diabetes mellitus. The odds of revascularization before amputation increased significantly over time (P = 0.035). CONCLUSION: Major and minor amputation rates were stable across England between 2003 and 2008, accompanied by a significant reduction in perioperative mortality. There were significant geographical variations in amputation rates, mortality rates and the below-knee : above-knee amputation ratio.

Event-by-event fluctuations of azimuthal particle anisotropy in Au+Au collisions at square root(sNN) = 200 GeV.

This Letter presents the first measurement of event-by-event fluctuations of the elliptic flow parameter v(2) in Au+Au collisions at square root(s(NN))=200 GeV as a function of collision centrality. The relative nonstatistical fluctuations of the v(2) parameter are found to be approximately 40%. The results, including contributions from event-by-event elliptic flow fluctuations and from azimuthal correlations that are unrelated to the reaction plane (nonflow correlations), establish an upper limit on the magnitude of underlying elliptic flow fluctuations. This limit is consistent with predictions based on spatial fluctuations of the participating nucleons in the initial nuclear overlap region. These results provide important constraints on models of the initial state and hydrodynamic evolution of relativistic heavy ion collisions.

High transverse momentum triggered correlations over a large pseudorapidity acceptance in Au + Au collisions at square root(s(NN)) = 200 GeV.

A measurement of two-particle correlations with a high transverse momentum trigger particle (p(T)(trig) > 2.5 GeV/c) is presented for Au+Au collisions at square root(s(NN)) = 200 GeV over the uniquely broad longitudinal acceptance of the PHOBOS detector (-4 < Delta eta < 2). A broadening of the away-side azimuthal correlation compared to elementary collisions is observed at all Delta eta. As in p+p collisions, the near side is characterized by a peak of correlated partners at small angle relative to the trigger particle. However, in central Au+Au collisions an additional correlation extended in Delta eta and known as the "ridge" is found to reach at least |Delta eta| approximately = 4. The ridge yield is largely independent of Delta eta over the measured range, and it decreases towards more peripheral collisions. For the chosen (p(T)(trig) cut, the ridge yield is consistent with zero for events with less than roughly 100 participating nucleons.

Re-interventions, readmissions and discharge destination: modern metrics for the assessment of the quality of care.

AIM: To determine whether administrative data can be used to determine metrics to inform the quality agenda. To determine the relationship between these metrics and the method of abdominal aortic aneurysm (AAA) repair undertaken. METHODS: The Hospital Episode Statistics (HES) data were taken for a 5-year period (01.04.2003-31.03.2008). Cases of elective AAA repair were identified. Outcomes were determined in terms of mortality, discharge destination, re-intervention rates and emergency readmission rates. The results were interpreted in light of whether AAA repair was open or endovascular and whether patients were octogenarians or younger patients. RESULTS: There were 18,060 elective AAA repairs with a mean in-hospital mortality rate of 5.9%. Of these 14,141 were open repairs with a mean mortality of 6.5% and 3919 EVAR (22%) with a mean mortality of 3.8%. EVAR patients were less likely to be discharged to ongoing care (p < 0.001) but were associated with a higher rate of re-intervention (p = 0.001) than open repairs. No differences were seen in one-year readmission rates. Octogenarians were more likely to undergo EVAR (p = 0.001), to be readmitted within 30-days (p = 0.009), to require further interventions on their index admission (p < 0.001) and less likely to be discharged home (p < 0.001) than younger patients. CONCLUSION: Administrative data can be used to identify metrics other than mortality and length of stay. These metrics might be used to inform service provision. In particular for AAA repair, differences in these outcomes were identified between open repair and EVAR and between octogenarians and younger patients.

Correlation between antibiotic use and resistance in a hospital: temporary and ward-specific observations.

OBJECTIVES: The objectives of this study were to determine (1) the increase in antimicrobial resistance to frequently used antibiotics in the hospital setting over time and (2) the correlation between the amount of use of an antibiotic in a specific medical specialty and the observed resistance to that antibiotic in that specialty. METHOD: The total use of antibiotics and the use of ciprofloxacin (CIP), co-amoxicillin + clavulanic acid (AMCL) and first and second-generation cephalosporins (CEF), respectively, in individual medical specialties were measured between 2001 and 2006 by means of prevalence surveys (two per year). The antimicrobial susceptibility patterns among E. coli isolated from hospitalized patients between 2003 and 2006 were obtained from the Laboratory Information System. Trends over time and correlation between use and resistance were calculated. RESULTS: 6,639 patients were included in the prevalence surveys, of whom 3.0% (195) were treated with CIP, 9.7% (642) with AMCL, and 3.5% (232) with CEF. 4,790 E. coli isolates were obtained from hospitalized patients. Resistance to all antibiotics significantly increased over time, with the regression line showing that the strongest increase in resistance was for CIP (2.6% per year). There were large variations in antimicrobial use between various medical specialties. A significant correlation was found between the ward-specific prevalence of use and the percentage of resistance for CIP (R = 0.81, p < 0.001) and AMCL (R = 0.82, p = 0.003). CONCLUSION: At the level of individual medical specialties within one hospital, a higher prevalence of antimicrobial use among patients was associated with a significantly higher observed antimicrobial resistance. The use of CIP was associated with a stronger increase in resistance than the use of beta-lactams.

System size, energy, and centrality dependence of pseudorapidity distributions of charged particles in relativistic heavy-ion collisions.

We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrt[s_{NN}]=22.4, 62.4, and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. A comparison of Cu+Cu and Au+Au results shows that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same N{part}/2A rather than the same N_{part}. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.

The difficult venous ulcer: case series of 177 ulcers referred for vascular surgical opinion following failure of conservative management.

Venous leg ulcers are common, chronic, debilitating, and expensive. Evidence supports use of compression bandaging, with superficial venous surgery in selected cases, but these interventions frequently fail to achieve healing. We describe a series of 152 consecutive referrals from a nurse-led specialist dermatology clinic to a vascular surgical service; a group posing particularly challenging problems. This observational study, with median follow-up of 18 months, describes outcomes in a number of important clinically identifiable subgroups. Its findings may assist service planning and discussion of the surgical role within multidisciplinary ulcer management.

Decontamination of the digestive tract and oropharynx in ICU patients.

BACKGROUND: Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting. METHODS: We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance. RESULTS: A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively. CONCLUSIONS: In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

System size, energy, pseudorapidity, and centrality dependence of elliptic flow.

This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

Use of topical corticosteroids on chronic leg ulcers.

OBJECTIVE: Topical corticosteroids are widely used in the management of chronic wounds, yet there is little evidence to support this. This pilot study aimed to identify current practice by three specialist nurses and to assess the efficacy of topical corticosteroids. METHOD: Data on healing, pain relief, exudate reduction and control of hypergranulation tissue were collected on 34 patients whose wounds were treated with topical corticosteroids prospectively in three centres over a three-month period. RESULTS: Twenty-seven patients (79%) benefited from the application of topical corticosteroid either in terms of healing, pain relief, exudate reduction or the control of hypergranulation tissue. Two wounds deteriorated and treatment was immediately withdrawn. CONCLUSION: Suppression of inflammation plays an important role in healing and pain relief. Applying topical corticosteroids to the wound can accelerate healing and reduce pain in certain cases. However, careful monitoring is essential as there is a risk of sensitisation with prolonged use as well as a potential increased risk of infection.

Energy dependence of directed flow over a wide range of pseudorapidity in Au + Au collisions at the BNL Relativistic Heavy Ion Collider.

We report on measurements of directed flow as a function of pseudorapidity in Au + Au collisions at energies of square root of SNN = 19.6, 62.4, 130 and 200 GeV as measured by the PHOBOS detector at the BNL Relativistic Heavy Ion Collider. These results are particularly valuable because of the extensive, continuous pseudorapidity coverage of the PHOBOS detector. There is no significant indication of structure near midrapidity and the data surprisingly exhibit extended longitudinal scaling similar to that seen for elliptic flow and charged particle pseudorapidity density.

System size and centrality dependence of charged hadron transverse momentum spectra in Au + Au and Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV.

We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems.