The experimental characterization of a high‐power pulsed semiconductor laser operating in the eye‐safe spectral range (wavelength around 1.5 μm), with an asymmetric waveguide structure, a 100 μm wide ...stripe, and a bulk active layer positioned very close to the p‐cladding, is reported. An anti‐reflection/high reflection coated laser with a stripe width of 100 μm exhibits a single‐facet output power over 25 W at a pumping current amplitude of 100 A.
We propose a large-area, cost-effective muon telescope detector (MTD) at mid-rapidity for the solenoidal tracker at the RHIC (STAR) and for the next generation of detectors at a possible electron-ion ...collider. We utilize large multi-gap resistive plate chambers with long readout strips (long-MRPC) in the detector design. The results from cosmic ray and beam tests show that the intrinsic timing and spatial resolution for a long-MRPC are 60-70 ps and ~1 cm, respectively. The performance of the prototype muon telescope detector at STAR indicates that muon identification at a transverse momentum of a few GeV/c can be achieved by combining information from track matching with the MTD, ionization energy loss in the time projection chamber and time-of-flight measurements. A primary muon over secondary muon ratio of better than 1/3 can be achieved. This provides a promising device for future quarkonium programs and primordial dilepton measurements at the RHIC. Simulations of the muon efficiency, the signal-to-background ratio of J/psi, the separation of 1S from 2S+3S states and the electron-muon correlation from charm pair production in the RHIC environment are presented.
Trust is important for the perception of many types of risk, including those relating to genetically modified (GM) food. Who the public trusts in any given circumstance, however, is not well ...understood. In this study of public trust regarding GM food, an exploratory factor analysis with Promax rotation reveals public classification of three common institutional types—evaluators, watchdogs, and merchants. The structure of relationships among these stakeholders can act to enable or constrain public support for this new technology. Evaluators—scientists, universities, and medical professionals—are the most trusted. Watchdogs—consumer advocacy organizations, environmental organizations, and media sources—are moderately trusted. Merchants—grocers and grocery stores, industry, and farmers—are least trusted. While the federal government is seen as closest to being an evaluator, it is not highly correlated with any of the factors. The lack of trust in the organizations with the greatest resources and responsibilities for ensuring the safety of GM food should be seen as an important obstacle to the adoption of the technology.
The long baseline between Earth and the Sun makes solar neutrinos an excellent test beam for exploring possible neutrino decay. The signature of such decay would be an energy-dependent distortion of ...the traditional survival probability which can be fit for using well-developed and high-precision analysis methods. Here a model including neutrino decay is fit to all three phases of $^{8}\mathrm{B}$ solar neutrino data taken by the Sudbury Neutrino Observatory (SNO). This fit constrains the lifetime of neutrino mass state ${{\nu}}_{2}$ to be > $8.08\times{}{10}^{{-}5}\text{ }\text{ }\mathrm{s}/\mathrm{eV}$ at 90% confidence. An analysis combining this SNO result with those from other solar neutrino experiments results in a combined limit for the lifetime of mass state ${{\nu}}_{2}$ of > $1.92\times{}{10}^{{-}3}\text{ }\text{ }\mathrm{s}/\mathrm{eV}$ at 90% confidence.
The forward time projection chamber in STAR Ackermann, K.H.; Bieser, F.; Brady, F.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Two cylindrical forward TPC detectors are described which were constructed to extend the phase space coverage of the STAR experiment to the region 2.5<|
η|<4.0. For optimal use of the available space ...and in order to cope with the high track density of central Au+Au collisions at RHIC, a novel design was developed using radial drift in a low diffusion gas. From prototype measurements a 2-track resolution of 1–
2
mm
is expected.
An asymmetric waveguide laser diode with a thick active layer operated with enhanced gain switching is shown to be able to produce ∼100 ps, ∼25 W optical pulses in fundamental transverse mode with ...∼15 A, ∼1.5 ns injection current pulses. A pulsed time-of-flight distance measurement demonstration utilizing this laser diode and a SPAD detector indicates centimetre-level precision and compensated accuracy from uncooperative targets at tens to hundreds of metres in a measurement time of a fraction of a second.
Background. The management of patients with severe, concomitant coronary and carotid artery occlusive disease is controversial.
Methods. Between 1975 and 1996, 512 patients (mean age, 64.9 years; 70% ...male) were admitted for coronary revascularization; 316 (61.7%) had asymptomatic, severe carotid disease (stenosis >70%) and 196 (38.3%) had symptomatic carotid disease (159 31.1% with transient ischemia and 37 7.2% with completed stroke). In group 1, coronary revascularization and carotid endarterectomy were simultaneously performed in 255 patients (49.8%) with unstable angina. In group 2 (staged approach), carotid endarterectomy was performed before coronary revascularization in 257 patients (50.2%) without unstable angina.
Results. Before 1986, the incidence of stroke and death was greater in group 1 (n = 149) than in group 2 (n = 156) (14 9.4% versus 4 2.6%;
p < 0.01). Since 1986, outcomes in group 1 (n = 106) and group 2 (n = 101) have been similar for stroke (2 1.9% versus 2 2.0%), death (4 3.8% versus 3 3.0%), and myocardial infarction (4 3.8% versus 5 5.0%). Significant univariate and multivariate predictors of adverse outcome were primarily heart-related (reoperation, intraaortic balloon use, ejection fraction <0.50, and angina grade 4 for death; age >70 years and congestive heart failure for stroke).
Conclusions. Despite highly selected populations, contemporary surgical results do not indicate that staged treatment of severe, concomitant coronary and carotid artery occlusive disease has an advantage over simultaneous treatment. Advances in myocardial protection and perioperative hemodynamic management may account for the low incidences of stroke and death in these operations.
Using 'general trust in institutions' and 'concepts of nature' as examples, the article analyzes the influence of cultural factors on sense-making of food biotechnology and the resulting public ...attitudes in the USA and Germany. According to the hypotheses investigated, different levels of trust and appreciation of nature explain part of the well-known differences in attitudes between both countries. The analysis of a cross-cultural survey of the general population shows that appreciation of nature is a predictor of attitudes in both countries. The higher appreciation of nature in Germany partly explains why attitudes towards food biotechnology are more negative in Germany than in the USA. The relationship between trust and attitudes is more complex than expected, however. Institutional trust is a moderate predictor of attitudes towards food biotechnology in the USA but not in Germany. To explain the varying effectiveness of trust in resolving innovation-related uncertainty we refer to differences in issue framing in both countries and to the higher degree of universalism and individualism in the USA. We conclude that the higher relevance of trust and the lower appreciation of nature make the U.S. culture more apt to assimilate technical innovations than the German culture.
PDF
