Demonstration of the temporal matter-wave Talbot effect for trapped matter waves

We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure

Azimuthal anisotropy at RHIC: the first and fourth harmonics

We report the first observations of the first harmonic (directed flow, v_1), and the fourth harmonic (v_4), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data tables are at http://www.star.bnl.gov/central/publications/pubDetail.php?id=3

Geophysical and atmospheric evolution of habitable planets

The evolution of Earth-like habitable planets is a complex process that depends on the geodynamical and geophysical environments. In particular, it is necessary that plate tectonics remain active over billions of years. These geophysically active environments are strongly coupled to a planet's host star parameters, such as mass, luminosity and activity, orbit location of the habitable zone, and the planet's initial water inventory. Depending on the host star's radiation and particle flux evolution, the composition in the thermosphere, and the availability of an active magnetic dynamo, the atmospheres of Earth-like planets within their habitable zones are differently affected due to thermal and nonthermal escape processes. For some planets, strong atmospheric escape could even effect the stability of the atmosphere

Mid-rapidity anti-proton to proton ratio from Au+Au collisions at sNN=130 \sqrt{s_{NN}} = 130 GeV

We report results on the ratio of mid-rapidity anti-proton to proton yields in Au+Au collisions at \rts = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of $|y|<0.5$ and 0.4 $<p_t<$ 1.0 GeV/$c$, the ratio is essentially independent of either transverse momentum or rapidity, with an average of $0.65\pm 0.01_{\rm (stat.)} \pm 0.07_{\rm (syst.)}$ for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the $p$-\pb pair production becomes important at mid-rapidity, a significant excess of baryons over anti-baryons is still present.Comment: 5 pages, 3 figures, accepted by Phys. Rev. Let

Patient recruitment in a challenging surgical trial : issues and possible solutions

Randomised Controlled Trials (RCTs) are regarded as a ‘gold standard’ technique to evaluate and compare clinical interventions. Strict ethical criteria dictate the participation of humans in clinical research, based on informed consent, voluntary decision making and putting patients’ interests first. Demand for RCTs in Trauma and Orthopaedics is high, but patient recruitment continues to pose a significant challenge, especially when the treatments being compared are obviously different. Lack of blinding, treatment preference and negative perception of random allocation to interventions are among the obstacles which need to be considered. Based on review and analysis of current knowledge, an attempt is made to develop a new recruitment process that incorporates high ethical standards and provision of the best possible clinical care for an individual patient. By integrating the principle of clinical equipoise, modern technology and statistical concepts, such as subjective probability, the Patient Eligibility Assessment through Clinical Equipoise (PEACE) framework has been introduced. This provides an alternative that could be used in trials where the fixed eligibility criteria approach is likely to fail. It was tested involving 77 real clinical cases from a national multi-centre trauma RCT, which compared contrasting treatments. A new trial recruitment approach aiming to avoid direct contact between a patient and a treating clinician was rolled out in the same trial. The feedback was collected from both the clinicians and the patients involved. Thematic analysis of 23 semi-structured interviews improved understanding of the various factors influencing patients’ decision about trial participation. Further typological analysis provided a valuable insight into the different attitudes that patients adopted when faced with the dilemma. In particular, that many are positive towards research involvement, but not comfortable with randomisation based on fixed eligibility criteria. According to these results, a new model for patient recruitment is suggested, which could be researched and tested in future trials

Best clinical care versus the common good of research : a solution for challenging surgical trials

Randomised controlled trials (RCTs) in surgery are expensive and labour intensive, yet considerable concern remains about applicability of results in clinical practice. Apart from quality issues, this lack of applicability is often due to strict eligibility criteria leading to selection bias. In addition, only a small proportion of eligible patients are randomised, since both clinicians and patients are rarely in equipoise and do not feel comfortable being excluded from the decision making process, especially when substantially different procedures (such as open versus minimally invasive or operative versus non-operative interventions) are compared or surgical innovations are involved. The Patient Eligibility Assessment through Clinical Equipoise (PEACE) methodological framework is introduced. In this framework, every provisionally eligible patient is regarded as a complex case which is assessed on line by an expert panel. Collected opinions including that of the submitting surgeon are processed to calculate the level of clinical equipoise. A sufficient level of equipoise for random treatment allocation is confirmed or a panel consensus in preference for a certain treatment is advised. The proposed framework was developed and panel assessment tested in collaboration with a national multicentre trauma randomised controlled trial comparing operative and non-operative interventions. 12 surgeons from nine hospitals acting as principal investigators in the trial formed the expert panel and assessed 77 real clinical cases eligible according to standard inclusion and exclusion criteria during the 3 year course of the trial. Because every case is assessed for eligibility, initial entrance criteria can be pragmatic and less specific than with the standard approach. A treating surgeon is involved in the decision process through submitting an opinion and has the backing of an expert panel when treatment options and trial participation is discussed with a patient. Cases where there is treatment consensus can also be researched, but should not be randomised on ethical grounds

Optimal configuration of the spiral linking technique for tendon repair. Biomechanical evaluation

A previous study described a new spiral linking technique for tendon repairs and demonstrated that it was strong enough to be used in clinical practice as an alternative to the Pulvertaft tendon weave repair. However the repairs were less stiff, needed slightly more tendon length for the same repair and were a little bulkier. In this study two variables have been changed with a view to improving the spiral technique. At first the number of spirals was reduced consecutively, keeping the same number of standard mattress sutures. Once the optimal number of spirals had been identified, repairs with different numbers of sutures were tested using an alternative cross-stitch technique. The spiral repair technique using two spirals linked with six sutures was at least as strong and stiff as a four-weave Pulvertaft technique and was also easier to do

Electromagnetic radiation detectors based on Josephson junctions: Effective Hamiltonian

We theoretically analyze two setups of low-energy single-photon counters based on Josephson junctions (JJs). For this, we propose two simple and general models based on the macroscopic quantum tunneling formalism (MQT). The first setup is similar to the photon counter based on the “cold-electron bolometer” (CEB), where the JJ replaces the CEB in the center of the superconducting antenna. In the second setup, the JJ is capacitively coupled to the antenna. We derive the Hamiltonians for the two setups, and we write the Schrödinger equations, taking into account both the antenna and the JJ. The quantum particles of the MQT models move in two-dimensional potential landscapes, which are parabolic along one direction and may have the form of a washboard potential along another direction. Such a potential landscape has a series of local minima, separated by saddle points. If the particle is prepared in the initial state in the metastable “ground state” of a local minimum, then the photon absorption causes it to jump into an excited state. If the excitation energy is bigger than the potential barrier seen by the quantum particle (the difference between the ground state and the saddle point), the photon is detected. The models are simple and allow us to do mostly analytical calculations. We show that the two setups are equivalent from the MQT point of view since one Hamiltonian can be transformed into the other by changes in variables. For typical values of the JJ and antenna parameters, the setups may work as counters of photons of wavelengths up to at least 1 cm. Dark count rates due to the phase particle tunneling directly from the ground state into the running state have also been evaluated