Signatures of Relativistic Helical Motion in the Rotation Measures of AGN Jets

Polarization has proved an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally dominated magnetic fields within jets. More recently, maps of the rotation measure (RM) in jets have for the first time probed the field geometry of the cool, moderately relativistic surrounding material. In most cases, clear signatures of toroidal magnetic field are detected, corresponding to gradients in RM profiles transverse to the jet. However, in many objects these profiles also display marked asymmetries which are difficult to explain in simple helical jet models. Furthermore, in some cases the RM profiles are strongly frequency and/or time dependent. Here we show that these features may be naturally accounted for by including relativistic helical motion in the jet model. In particular, we are able to reproduce bent RM profiles observed in a variety of jets, frequency dependent RM profile morphologies and even the time dependence of the RM profiles of knots in 3C 273. Finally, we predict that some sources may show reversals in their RM profiles at sufficiently high frequencies, depending upon the the ratio of the components of jet sheath velocity transverse and parallel to the jet. Thus, multi-frequency RM maps promise a novel way in which to probe the velocity structure of relativistic outflows.Comment: 5 pages, 4 figures, submitted to ApJ

Group L: T-shirt2 Cutter

The T-shirt square cutter was commissioned by fashion design professor at Washington University, Dr. Mary RuppertStroescu who has developed a method of turning T-shirts that might have otherwise been thrown away into a unique, woven fabric. Dr. Ruppert-Stroescu cuts T-shirts into either strips or squares that she then quilts together, she uses this fabric to make one-of-a-kind clothes, bags, and rugs. Though she is proficient at weaving the fabric scraps together, cutting the Tshirts was a very time-consuming process – it takes her at least 20 minutes to cut a T-shirt into squares by hand. Our team was tasked with designing and building a machine that would speed up the cutting process for her. With a budget of $250, we have spent the semester designing, building, and testing a machine that would cut T-shirts into squares safely and with minimal effort from the user. This report details the entire design process, beginning with the assessing user needs so we could brainstorm ideas. After a concept was selected based on certain criteria, we built and tested a proof of concept. After assessing the failures and successes of the proof of concept prototype we were able to build a final prototype that was ultimately able to successfully cut a T-shirt into squares

Closed-circuit television welding- electrode guidance system

Closed-circuit TV camera is mounted parallel to electrode and moves along with it. Camera is scanned along seam so seam is viewed parallel with scan lines on TV monitor. Two fiber optics illuminators are attached to guidance system; they illuminate seam for TV camera

Proposal for an Advanced Structural Elective Pertaining to Fire Protection

ARCE 401 Fire Protection is a class that will finally give ARCE students an introduction to fire-resilience and its major importance in the structural and planning spheres. The class would have a structural emphasis along with interdisciplinary qualities, unlike the graduate classes offered in the CE and ME departments. ARCE 401 covers a broad spectrum of topics and is meant to bring ARCE students closer to a comprehensive understanding of the overall work environment

Psychological perspectives in urinary incontinence: a metasynthesis

Introduction: Urinary incontinence with co-morbid depression has been found to have a significant effect on quality of life. Examining the associations between the psychosocial factors related to urinary incontinence and mental health may help in improving the care for patients with these conditions. The aim of this research study is to explore the relationship between mental health status and urinary incontinence, focusing on the role of psychosocial factors. Materials and Methods: A search of Medline, CINAHL and SCOPUS databases yielded 15 studies on the topic, and 10 studies were found to be in scope. A metasynthesis using Noblit and Hare’s approach of meta-ethnography was undertaken. This involved a number of steps including determining how studies are related and identifying major themes. Results: Three psychosocial aspects of urinary incontinence appear to influence mental health status: living with, management of and attitudes about incontinence. Other smaller component themes included control, seeking help and personal beliefs. Discussion: Psychosocial factors appear to mediate the relationship between urinary incontinence and mental health status. An increased awareness of the major psychosocial issues that can influence both incontinence and mental health may contribute to a better management of the condition as well as reduce the burden of the condition on individuals. Conclusion: Incontinence and psychological wellbeing are intertwined and this adversely affects a number of aspects of life. Enquiring about the mental health status of those with incontinence should include an assessment of psychosocial factors to help reduce the burden of incontinence. To improve the management of these conditions, further research should investigate whether psychological issues precede incontinence or vice versa.JC Avery, AJ Braunack-Mayer, NP Stocks, AW Taylor, P Dugga

Food habits, lifestyle factors and mortality among oldest old Chinese: the Chinese longitudinal healthy longevity survey (CLHLS)

There are few studies reporting the association between lifestyle and mortality among the oldest old in developing countries. We examined the association between food habits, lifestyle factors and all-cause mortality in the oldest old (¥80 years) using data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). In 1998/99, 8959 participants aged 80 years and older took part in the baseline survey. Follow-up surveys were conducted every two to three years until 2011. Food habits were assessed using an in-person interview. Deaths were ascertained from family members during follow-up. Cox and Laplace regression were used to assess the association between food habits, lifestyle factors and mortality risk. There were 6626 deaths during 31,926 person-years of follow-up. Type of staple food (rice or wheat) was not associated with mortality. Daily fruit and vegetable intake was inversely associated with a higher mortality risk (hazard ratios (HRs): 0.85 (95% CI (confidence interval) 0.77–0.92), and 0.74 (0.66–0.83) for daily intake of fruit and vegetables, respectively). There was a positive association between intake of salt-preserved vegetables and mortality risk (consumers had about 10% increase of HR for mortality). Fruit and vegetable consumption were inversely, while intake of salt-preserved vegetables positively, associated with mortality risk among the oldest old. Undertaking physical activity is beneficial for the prevention of premature death.Zumin Shi, Tuohong Zhang, Julie Byles, Sean Martin, Jodie C. Avery and Anne W. Taylo

ENERGY FLOW AND GROUND REACTION FORCE PREDICTORS OF BAT SWING SPEED DURING PITCHED BALL BATTING IN PROFESSIONAL BASEBALL PLAYERS

The purposes of this study are to determine how mechanical energy is absorbed, generated, and transferred during baseball hitting for professional athletes. This study also aims to identify which ground reaction force and energy flow variables influence bat speed. The findings of this study suggest that energy flows from the trunk to the lead leg as the pelvis rotates towards the pitcher. The results of this study emphasize the crucial role of the back leg and trunk during acceleration as well as eccentric contraction of muscles in the lead leg and trunk to decelerate during follow-through. Training strategies that improve muscular strength and mobility of the trunk and hips can be implemented to potentially increase bat speed

Understanding the Geometry of Astrophysical Magnetic Fields

Faraday rotation measurements have provided an invaluable technique with which to measure the properties of astrophysical magnetized plasmas. Unfortunately, typical observations provide information only about the density-weighted average of the magnetic field component parallel to the line of sight. As a result, the magnetic field geometry along the line of sight, and in many cases even the location of the rotating material, is poorly constrained. Frequently, interpretations of Faraday rotation observations are dependent upon underlying models of the magnetic field being probed (e.g., uniform, turbulent, equipartition). However, we show that at sufficiently low frequencies, specifically below roughly 13 (RM/rad m^-2)^(1/4) (B/G)^(1/2) MHz, the character of Faraday rotation changes, entering what we term the ``super-adiabatic regime'' in which the rotation measure is proportional to the integrated absolute value of the line-of-sight component of the field. As a consequence, comparing rotation measures at high frequencies with those in this new regime provides direct information about the geometry of the magnetic field along the line of sight. Furthermore, the frequency defining the transition to this new regime, nu_SA, depends directly upon the local electron density and magnetic field strength where the magnetic field is perpendicular to the line of sight, allowing the unambiguous distinction between Faraday rotation within and in front of the emission region. Typical values of nu_SA range from 10 kHz to 10 GHz, depending upon the details of the Faraday rotating environment. In particular, for resolved AGN, including the black holes at the center of the Milky Way (Sgr A*) and M81, nu_SA ranges from roughly 10 MHz to 10 GHz, and thus can be probed via existing and up-coming ground-based radio observatories.Comment: 13 pages, 5 figures, submitted to Ap

North Korea: U.S. Relations, Nuclear Diplomacy, and Internal Situation

Although the primary focus of U.S. policy toward North Korea is the nuclear weapons program, there are a host of other issues, which this report explores through an overview of the U.S.-North Korea relationship, including an emphasis on the diplomacy of the Six-Party Talks. Please refer to the list at the end of this report for the full list of CRS reports focusing on other North Korean issues