Pressure measurements in a low-density nozzle plume for code verification

Measurements of Pitot pressure were made in the exit plane and plume of a low-density, nitrogen nozzle flow. Two numerical computer codes were used to analyze the flow, including one based on continuum theory using the explicit MacCormack method, and the other on kinetic theory using the method of direct-simulation Monte Carlo (DSMC). The continuum analysis was carried to the nozzle exit plane and the results were compared to the measurements. The DSMC analysis was extended into the plume of the nozzle flow and the results were compared with measurements at the exit plane and axial stations 12, 24 and 36 mm into the near-field plume. Two experimental apparatus were used that differed in design and gave slightly different profiles of pressure measurements. The DSMC method compared well with the measurements from each apparatus at all axial stations and provided a more accurate prediction of the flow than the continuum method, verifying the validity of DSMC for such calculations

Shining a Gluon Beam Through Quark-Gluon Plasma

We compute the energy density radiated by a quark undergoing circular motion in strongly coupled $\mathcal N = 4$ supersymmetric Yang-Mills plasma. If it were in vacuum, this quark would radiate a beam of strongly coupled radiation whose angular distribution has been characterized and is very similar to that of synchrotron radiation produced by an electron in circular motion in electrodynamics. Here, we watch this beam of gluons getting quenched by the strongly coupled plasma. We find that a beam of gluons of momenta $\sim q \gg \pi T$ is attenuated rapidly, over a distance $\sim q^{1/3} (\pi T)^{-4/3}$ in a plasma with temperature $T$. As the beam propagates through the plasma at the speed of light, it sheds trailing sound waves with momenta $\lesssim \pi T$. Presumably these sound waves would thermalize in the plasma if they were not hit soon after their production by the next pulse of gluons from the lighthouse-like rotating quark. At larger and larger $q$, the trailing sound wave becomes less and less prominent. The outward going beam of gluon radiation itself shows no tendency to spread in angle or to shift toward larger wavelengths, even as it is completely attenuated. In this regard, the behavior of the beam of gluons that we analyze is reminiscent of the behavior of jets produced in heavy ion collisions at the LHC that lose a significant fraction of their energy without appreciable change in their angular distribution or their momentum distribution as they plow through the strongly coupled quark-gluon plasma produced in these collisions.Comment: 16 pages, 4 figure

Decision-analytic cost-effectiveness model to compare prostate cryotherapy to androgen deprivation therapy for treatment of radiation recurrent prostate cancer

Objective: To determine the cost-effectiveness of salvage cryotherapy (SC) in men with radiation recurrent prostate cancer (RRPC). Design: Cost-utility analysis using decision analytic modelling by a Markov model. Setting and methods: Compared SC and androgen deprivation therapy (ADT) in a cohort of patients with RRPC (biopsy proven local recurrence, no evidence of metastatic disease). A literature review captured published data to inform the decision model, and resource use data were from the Scottish Prostate Cryotherapy Service. The model was run in monthly cycles for RRPC men, mean age of 70 years. The model was run over the patient lifetime, to assess changes in patient health states and the associated quality of life, survival and cost impacts. Results are reported in terms of the discounted incremental costs and discounted incremental quality-adjusted life years (QALYs) gained between the 2 alternative interventions. Probabilistic sensitivity analysis used a 10 000 iteration Monte Carlo simulation. Results: SC has a high upfront treatment cost, but delays the ongoing monthly cost of ADT. SC is the dominant strategy over the patient lifetime; it is more effective with an incremental 0.56 QALY gain (95% CI 0.28 to 0.87), and less costly with a reduced lifetime cost of £29 719 (€37 619) (95% CI −51 985 to −9243). For a ceiling ratio of £30 000, SC has a 100% probability to be cost-effective. The cost neutral point was at 3.5 years, when the upfront cost of SC (plus any subsequent cumulative cost of side effects and ADT) equates the cumulative cost in the ADT arm. Limitations of our model may arise from its insensitivity to parameter or structural uncertainty. Conclusions: The platform for SC versus ADT cost-effective analysis can be employed to evaluate other treatment modalities or strategies in RRPC. SC is the dominant strategy, costing less over a patient's lifetime with improvements in QALYs

A Resource-Free Evaluation Metric for Cross-Lingual Word Embeddings Based on Graph Modularity

Cross-lingual word embeddings encode the meaning of words from different languages into a shared low-dimensional space. An important requirement for many downstream tasks is that word similarity should be independent of language - i.e., word vectors within one language should not be more similar to each other than to words in another language. We measure this characteristic using modularity, a network measurement that measures the strength of clusters in a graph. Modularity has a moderate to strong correlation with three downstream tasks, even though modularity is based only on the structure of embeddings and does not require any external resources. We show through experiments that modularity can serve as an intrinsic validation metric to improve unsupervised cross-lingual word embeddings, particularly on distant language pairs in low-resource settings.Comment: Accepted to ACL 2019, camera-read

Especies nuevas de Elateridae (Coleoptera) de Madre de Dios, Perú, con nuevos cambios taxonómicos y registros de distribución

The Elateridae fauna of Peru is updated with species new to science, new country records and new taxonomic combinations from the Madre de Dios region. Ten species representing eight genera are described as new: Conoderus wachiperi new species (Agrypninae, Oophorini) Cosmesus aca new species (Elaterinae, Pomachilini), Dipropus amarakaeri new species and Dipropus losamigos new species (Elaterinae, Ampedini, Dicrepidiina), Esthesopus machiguenga new species (Cardiophorinae), Glyphonyx peruanus new species (Elaterinae, Adrastini), Lissomus carmen new species (Lissominae), Paradonus kosnipata new species (Negastriinae), and Pomachilius qusqu new species and Pomachilius wayqecha new species (Elaterinae, Pomachilini). Aeolus platynotus Candèze is changed to Conoderus platynotus (Candèze) new combination and Aeolus ticuna Johnson is changed to Conoderus ticuna (Johnson) new combination (Agrypninae, Oophorini); and Crigmus brunnipilis (Candèze) is changed to Probothrium brunnipilis (Candèze) new combination (Elaterinae, Elaterini). Twenty-seven (27) species, the genera Glyphonyx Candèze and Paradonus Stibick, the tribe Adrastini, and the subfamily Negastriinae are added to the Peru faunal list. There are now 201 species representing 48 genera and 9 subfamilies recorded from Peru.La fauna Elateridae del Perú se actualiza con especies nuevas para la ciencia, nuevos registros de países y nuevas combinaciones taxonómicas de la región de Madre de Dios. Diez especies que representan ocho géneros se describen como nuevas: Conoderus wachiperi nueva especie, Cosmesus aca nueva especie, Dipropus amarakaeri nueva especies, Dipropus losamigos, nueva especie, Esthesopus machiguenga nueva especie, Glyphonyx peruanus nueva especie, Lissomus carmen nueva especie, Paradonus kosnipata nueva especie, Pomachilius qusqu nueva especie, Pomachilius wayqecha nueva especie. Aeolus ticuna Johnson se cambia a Conoderus ticuna (Johnson) nueva combinación, Aeolus platynotus Candèze se cambia a Conoderus platynotus (Candèze) nueva combinación, y Crigmus brunnipilis (Candèze) se cambia a Probothrium brunnipilis (Candèze). Veintisiete (27) especies, los géneros Glyphonyx Candèze y Paradonus Stibick, la tribu Adrastini y la subfamilia Negastriinae se agregan a la lista de fauna de Perú. Ahora hay 201 especies que representan 48 géneros y 9 subfamilias se registran en el Perú

An Evaluation of the Cost of Family Law Disputes: Measuring the Cost Implication of Various Dispute Resolution Methods

The Canadian Forum on Civil Justice contracted the Canadian Research Institute for Law and the Family to conduct a project measuring the cost implications of various dispute resolution methods for resolving family law disputes. Despite the greater emphasis in recent years on the importance of access to justice and the need to resolve family matters outside the court, there is little research on the effectiveness of various dispute resolution methods, and even less on the cost of the different approaches

Experimental limits of ghost diffraction: Popper’s thought experiment

Quantum ghost diffraction harnesses quantum correlations to record diffraction or interference features using photons that have never interacted with the diffractive element. By designing an optical system in which the diffraction pattern can be produced by double slits of variable width either through a conventional diffraction scheme or a ghost diffraction scheme, we can explore the transition between the case where ghost diffraction behaves as conventional diffraction and the case where it does not. For conventional diffraction the angular extent increases as the scale of the diffracting object is reduced. By contrast, we show that no matter how small the scale of the diffracting object, the angular extent of the ghost diffraction is limited (by the transverse extent of the spatial correlations between beams). Our study is an experimental realisation of Popper’s thought experiment on the validity of the Copenhagen interpretation of quantum mechanics. We discuss the implication of our results in this context and explain that it is compatible with, but not proof of, the Copenhagen interpretation

MEASURING THE MASS OF 4UO900-40 DYNAMICALLY

Accurate measurements of neutron star masses are needed to constrain the equation of state of neutron star matter - of importance to both particle physics and the astrophysics of neutron stars - and to identify the evolutionary track of the progenitor stars that form neutron stars. The best measured values of the mass of 4UO900-40 (= Vela XR-l), 1.86 +/- 0.16 Msun (Barziv et al. 2001) and 1.93 +/- 0.20 Msun (Abubekerov et al. 2004), make it a leading candidate for the most massive neutron star known. The direct relationship between the maximum mass of neutron stars and the equation of state of ultra-dense matter makes 4UO900-40 an important neutron star mass to determine accurately. The confidence interval on previous mass estimates, obtained from observations that include parameters determined by non-dynamical methods, are not small enough to significantly restrict possible equations of state. We describe here a purely dynamical method for determining the mass of 4UO900-40, an X-ray pulsar, using the reprocessed UV pulses emitted by its BO.5Ib companion. One can derive the instantaneous radial velocity of each component by simultaneous X-ray and UV observations at the two quadratures of the system. The Doppler shift caused by the primary's rotational velocity and the illumination pattern of the X-rays on the primary, two of the three principal contributors to the uncertainty on the derived mass of the neutron star, almost exactly cancel by symmetry in this method. A heuristic measurement of the mass of 4UO900-40 using observations obtained previously with the High Speed Photometer on HST is given in Appendix A