Orifice plates in a shock tube

This note points out some interesting aspects of a recent study of the flow resulting from the use of area change near the diaphragm of a shock tube. (1) Earlier studies (2,3) have been directed toward the use of area change for increasing the available shock speed, and thus have considered geometries where A4/A1 > 1 and A*/A1 = 1 [see notation on Fig. 1(a)]. In the current work, shock tubes with arbitrary values of these parameters are considered over the complete range of Ms (the shock Mach number)

Processes on Unimodular Random Networks

We investigate unimodular random networks. Our motivations include their characterization via reversibility of an associated random walk and their similarities to unimodular quasi-transitive graphs. We extend various theorems concerning random walks, percolation, spanning forests, and amenability from the known context of unimodular quasi-transitive graphs to the more general context of unimodular random networks. We give properties of a trace associated to unimodular random networks with applications to stochastic comparison of continuous-time random walk.Comment: 66 pages; 3rd version corrects formula (4.4) -- the published version is incorrect --, as well as a minor error in the proof of Proposition 4.10; 4th version corrects proof of Proposition 7.1; 5th version corrects proof of Theorem 5.1; 6th version makes a few more minor correction

Exploring notions of genre in 'academic literacies' and 'writing across the curriculum': approaches across countries and contexts

The SIGET IV panel on genre in Writing Across the Curriculum (WAC) and “academic literacies” (ACLITS) has set rolling a discussion of the similarities and differences in the two traditions, the former originating in the US in the early 1970s, the latter originating in England in the early 1990s. This paper maps out some elements of each in relation to the other and to genre, which we hope will set in motion further discussions and cross-fertilization

Latino Acculturative Stress Implications, Psychotherapeutic Processes, and Group Therapy

The Latino population is the fastest growing ethnic minority group in the United States. Yet, Latinos do not receive adequate mental health treatment due to the lack of cultural sensitivity regarding the necessity of bilingual and bicultural staff and culturally modified therapies. The difficulties associated with Latinos wrestling to preserve their native culture while also adjusting to the new dominant U.S. culture may cause them to experience acculturative stress. This specific distress may lead Latinos to implement maladaptive coping strategies that could influence Latino risk factors regarding unemployment, poverty, alcohol and drug abuse, aggressive behavior, mental health issues, and suicide rates. After reviewing the research focused on Latinos, Motivational Interviewing, Cognitive Behavioral Therapy, and Interpersonal Therapy were three major orientations aimed at individual therapy with Latinos while Cognitive Behavioral Group Therapy and psychoeducational groups dominated group therapy literature with Latinos. This review concluded the importance of incorporating cultural values and addressing socio-psychological stressors in therapy in order to produce significant treatment efficacy. Nonetheless, the rapidly increasing Latino population and genuine lack of cultural awareness requires continued research on culturally modifying other treatment modalities, multicultural competency for mental health professionals, and graduate program incorporation of a language component to stimulate interest with this needy population

The multi-wavelength polarization of Cygnus X-1

Polarization measurements of the microquasar Cygnus X-1 exist at gamma-ray, X-ray, UV, optical and radio frequencies. The gamma-ray emission has been shown to be highly linearly polarized. Here, we present new infrared polarimetric data of Cygnus X-1 taken with the 10.4-m Gran Telescopio Canarias and the 4.2-m William Herschel Telescope. We show that the broadband, radio to gamma-ray flux spectrum and polarization spectrum in the hard state are largely consistent with a simple phenomenological model of a strongly polarized synchrotron jet, an unpolarized Comptonized corona and a moderately polarized interstellar dust component. In this model, the origin of the gamma-ray, X-ray and some of the infrared polarization is the optically thin synchrotron power law from the inner regions of the jet. The model requires the magnetic field in this region to be highly ordered and perpendicular to the axis of the resolved radio jet. This differs to studies of some other X-ray binaries, in which the magnetic field is turbulent, variable and aligned with the jet axis. The model is able to explain the approximate polarization strength and position angle at all wavelengths including the detected X-ray (3 - 5 keV) polarization, except the observed position angle of the gamma-ray polarization, which differs to the model by ~ 60 degrees. Past numerical modelling has shown that a curved synchrotron spectrum can produce a shift in position angle by ~ 60 degrees, which may account for this.Comment: Accepted in MNRA