Idler-resonant femtosecond optical parametric oscillator with high mid-infra-red beam quality

We report an idler-resonant femtosecond optical parametric oscillator (OPO) with average output power of 520 mW, repetition-rate of 80 MHz, pulse duration of 90 fs and nearly diffraction-limited beam quality at ~2.4 µm

Complications of pregnancy and delivery in relation to psychosis in adult life: data from the British perinatal mortality survey sample

Original article can be found at: http://www.pubmedcentral.nih.gov/tocrender.fcgi?iid=137629 Copyright BMJ PublishingTo evaluate whether events occurring at or around the time of birth contribute to the onset of psychotic illness in adult life.Peer reviewe

16-µJ pulse energy, picosecond, narrow-linewidth master oscillator power amplifier using direct amplification

We present a gain-switched-diode-seeded 1034.5nm master oscillator power amplifier, employing direct amplification through standard commercial Yb3+-doped fibres to generate 15.6µJ-pulse-energy, 126kW-peak-power, picosecond pulses with 3dB spectral bandwidth of 0.87nm

Effect of statins on atrial fibrillation: collaborative meta-analysis of published and unpublished evidence from randomised controlled trials

Objective To examine whether statins can reduce the risk of atrial fibrillation. Design Meta-analysis of published and unpublished results from larger scale statin trials, with comparison of the findings against the published results from smaller scale or shorter duration studies. Data sources Medline, Embase, and Cochrane's CENTRAL up to October 2010. Unpublished data from longer term trials were obtained through contact with investigators. Study selection Randomised controlled trials comparing statin with no statin or comparing high dose versus standard dose statin; all longer term trials had at least 100 participants and at least six months' follow-up. Results In published data from 13 short term trials (4414 randomised patients, 659 events), statin treatment seemed to reduce the odds of an episode of atrial fibrillation by 39% (odds ratio 0.61, 95% confidence interval 0.51 to 0.74; P<0.001), but there was significant heterogeneity (P<0.001) between the trials. In contrast, among 22 longer term and mostly larger trials of statin versus control (105 791 randomised patients, 2535 events), statin treatment was not associated with a significant reduction in atrial fibrillation (0.95, 0.88 to 1.03; P=0.24) (P<0.001 for test of difference between the two sets of trials). Seven longer term trials of more intensive versus standard statin regimens (28 964 randomised patients and 1419 events) also showed no evidence of a reduction in the risk of atrial fibrillation (1.00, 0.90 to 1.12; P=0.99). Conclusions The suggested beneficial effect of statins on atrial fibrillation from published shorter term studies is not supported by a comprehensive review of published and unpublished evidence from larger scale trials

1.9µm operation of a Tm:Lead germanate glass waveguide laser

We report what we believe to be the first planar-technology waveguide laser in the 2-µm region. Laser operation of the 3H4 to 3H6 transition of Tm3+ ions in a lead germanate glass host has been observed in an ion-implanted planar waveguide

A picosecond optical parametric oscillator synchronously pumped by an amplified gain-switched laser diode

We demonstrate a picosecond optical parametric oscillator synchronously pumped by a fiber-amplified gain-switched laser diode. Up to 7.3W at 1.54µm and 3.1W at 3.4µm is obtained at pulse repetition rates between 114.8 and 918.4MHz

The power of quantum systems on a line

We study the computational strength of quantum particles (each of finite dimensionality) arranged on a line. First, we prove that it is possible to perform universal adiabatic quantum computation using a one-dimensional quantum system (with 9 states per particle). This might have practical implications for experimentalists interested in constructing an adiabatic quantum computer. Building on the same construction, but with some additional technical effort and 12 states per particle, we show that the problem of approximating the ground state energy of a system composed of a line of quantum particles is QMA-complete; QMA is a quantum analogue of NP. This is in striking contrast to the fact that the analogous classical problem, namely, one-dimensional MAX-2-SAT with nearest neighbor constraints, is in P. The proof of the QMA-completeness result requires an additional idea beyond the usual techniques in the area: Not all illegal configurations can be ruled out by local checks, so instead we rule out such illegal configurations because they would, in the future, evolve into a state which can be seen locally to be illegal. Our construction implies (assuming the quantum Church-Turing thesis and that quantum computers cannot efficiently solve QMA-complete problems) that there are one-dimensional systems which take an exponential time to relax to their ground states at any temperature, making them candidates for being one-dimensional spin glasses.Comment: 21 pages. v2 has numerous corrections and clarifications, and most importantly a new author, merged from arXiv:0705.4067. v3 is the published version, with additional clarifications, publisher's version available at http://www.springerlink.co

Are markers of inflammation more strongly associated with risk for fatal than for nonfatal vascular events?

<p><b>Background:</b> Circulating inflammatory markers may more strongly relate to risk of fatal versus nonfatal cardiovascular disease (CVD) events, but robust prospective evidence is lacking. We tested whether interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen more strongly associate with fatal compared to nonfatal myocardial infarction (MI) and stroke.</p> <p><b>Methods and Findings:</b> In the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER), baseline inflammatory markers in up to 5,680 men and women aged 70-82 y were related to risk for endpoints; nonfatal CVD (i.e., nonfatal MI and nonfatal stroke [n = 672]), fatal CVD (n = 190), death from other CV causes (n = 38), and non-CVD mortality (n = 300), over 3.2-y follow-up. Elevations in baseline IL-6 levels were significantly (p = 0.0009; competing risks model analysis) more strongly associated with fatal CVD (hazard ratio [HR] for 1 log unit increase in IL-6 1.75, 95% confidence interval [CI] 1.44-2.12) than with risk of nonfatal CVD (1.17, 95% CI 1.04-1.31), in analyses adjusted for treatment allocation. The findings were consistent in a fully adjusted model. These broad trends were similar for CRP and, to a lesser extent, for fibrinogen. The results were also similar in placebo and statin recipients (i.e., no interaction). The C-statistic for fatal CVD using traditional risk factors was significantly (+0.017; p<0.0001) improved by inclusion of IL-6 but not so for nonfatal CVD events (p = 0.20).</p> <p><b>Conclusions:</b> In PROSPER, inflammatory markers, in particular IL-6 and CRP, are more strongly associated with risk of fatal vascular events than nonfatal vascular events. These novel observations may have important implications for better understanding aetiology of CVD mortality, and have potential clinical relevance.</p&gt