Can Multi-threaded Flux Tubes in Coronal Arcades Support a Magnetohydrodynamic Avalanche?

Magnetohydrodynamic (MHD) instabilities allow energy to be released from stressed magnetic fields, commonly modelled in cylindrical flux tubes linking parallel planes, but, more recently, also in curved arcades containing flux tubes with both footpoints in the same photospheric plane. Uncurved cylindrical flux tubes containing multiple individual threads have been shown to be capable of sustaining an MHD avalanche, whereby a single unstable thread can destabilise many. We examine the properties of multi-threaded coronal loops, wherein each thread is created by photospheric driving in a realistic, curved coronal arcade structure (with both footpoints of each thread in the same plane). We use three-dimensional MHD simulations to study the evolution of single- and multi-threaded coronal loops, which become unstable and reconnect, while varying the driving velocity of individual threads. Experiments containing a single thread destabilise in a manner indicative of an ideal MHD instability and consistent with previous examples in the literature. The introduction of additional threads modifies this picture, with aspects of the model geometry and relative driving speeds of individual threads affecting the ability of any thread to destabilise others. In both single- and multi-threaded cases, continuous driving of the remnants of disrupted threads produces secondary, aperiodic bursts of energetic release.

Flux Rope Formation Due to Shearing and Zipper Reconnection

Zipper reconnection has been proposed as a mechanism for creating most of the twist in the flux tubes that are present prior to eruptive flares and coronal mass ejections. We have conducted a first numerical experiment on this new regime of reconnection, where two initially untwisted parallel flux tubes are sheared and reconnected to form a large flux rope. We describe the properties of this experiment, including the linkage of magnetic flux between concentrated flux sources at the base of the simulation, the twist of the newly formed flux rope, and the conversion of mutual magnetic helicity in the sheared pre-reconnection state into the self-helicity of the newly formed flux rope.

Mental Health Pathways Linking Childhood Maltreatment to Interpersonal Revictimization During Adolescence for Girls in the Child Welfare System

This study compares the association of histories of childhood emotional, physical, and sexual abuse, and physical neglect with revictimization among adolescent girls, and investigates the role of posttraumatic stress and symptoms of depression as mediators. Participants were 234 girls aged 12 to 19 years, who have been involved with the child welfare system in a Midwestern urban area. Data were collected from baseline surveys of a trauma-focused group program to which the participants were referred. The majority of participants were youths of color (75%) who were primarily African American (70%), and the remaining participants were White, non-Hispanic (25%). Data were collected through surveys that assessed histories of child abuse and neglect, symptoms of posttraumatic stress and depression, and experiences of physical, verbal, and relational revictimization in the last 3 months. All types of abuse and neglect were significantly associated with higher frequencies of revictimization and higher levels of posttraumatic stress and depressive symptoms. Parallel mediation analyses demonstrated that both posttraumatic stress and depression fully mediated the relationships between emotional abuse and revictimization, and sexual abuse and revictimization. Physical abuse was fully mediated by posttraumatic stress, but not by depression. Results also indicated that neither posttraumatic stress nor depression were mediators for the relationship between neglect and revictimization. There were similar pathways to revictimization in adolescents from emotional and sexual abuse through posttraumatic stress and depression. Evidence is mounting for the deleterious effects of emotional abuse. There is evidence that treatment of both posttraumatic stress and depression in emotionally and sexually abused adolescents involved in child welfare is warranted to prevent future revictimization.

Childhood Abuse and Aggression in Adolescent Girls Involved in Child Welfare: The Role of Depression and Posttraumatic Stress

This study investigated the relationship between histories of childhood abuse and aggressive behaviors among adolescent girls involved in child welfare, and determined whether symptoms of post-traumatic stress and depression mediated this relationship. Participants were 237 girls ages 12-19 years. Overall, results indicated 89 % of the adolescents endorsed at least one aggressive behavior towards others. Specifically, 72.0 % engaged in physical aggression, 78.5 % engaged in non-physical aggression, and 51.5 % endorsed relational aggression. Greater severity of emotional and physical abuse were significantly associated with a higher frequency of aggressive behaviors. Sexual abuse was not significantly related to aggression. Post-traumatic stress and depression fully mediated the relationship between emotional abuse and aggression, controlling for race, service use, and living situation. The linkages between physical abuse and aggression were not mediated by either post-traumatic stress or depression. Findings suggest that among adolescent girls with histories of emotional abuse, post-traumatic stress and depression represent potential modifiable risk factors to target for reducing aggression.

A central support system can facilitate implementation and sustainability of a Classroom-based Undergraduate Research Experience (CURE) in Genomics

In their 2012 report, the President's Council of Advisors on Science and Technology advocated "replacing standard science laboratory courses with discovery-based research courses"-a challenging proposition that presents practical and pedagogical difficulties. In this paper, we describe our collective experiences working with the Genomics Education Partnership, a nationwide faculty consortium that aims to provide undergraduates with a research experience in genomics through a scheduled course (a classroom-based undergraduate research experience, or CURE). We examine the common barriers encountered in implementing a CURE, program elements of most value to faculty, ways in which a shared core support system can help, and the incentives for and rewards of establishing a CURE on our diverse campuses. While some of the barriers and rewards are specific to a research project utilizing a genomics approach, other lessons learned should be broadly applicable. We find that a central system that supports a shared investigation can mitigate some shortfalls in campus infrastructure (such as time for new curriculum development, availability of IT services) and provides collegial support for change. Our findings should be useful for designing similar supportive programs to facilitate change in the way we teach science for undergraduates.

Recruiting Fathers to Parenting Programs: Advice from Dads and Fatherhood Program Providers

The benefits of high-quality father-child relationships for fathers and children alike are well documented. While evidence suggests parenting programs can improve the quality of father-child relationships, few fathers participate in such programs. This qualitative study aims to fill the gap in knowledge on best practices for recruiting urban African American fathers, a group of fathers with unique parenting challenges, to parenting programs. Focus groups were conducted with 29 fathers to gain their perspectives on recruitment strategies. Semi-structured interviews were also conducted with a nationwide sample of 19 fatherhood program providers to learn about their most successful recruitment strategies. Recruitment strategies based on emergent themes from the focus groups and interviews are presented here. Themes included using word-of-mouth recruitment, increasing advertising, targeting advertising specifically to urban African American fathers, providing transportation and incentives, recruiting through the courts, collaborating with other community agencies, and offering parenting programming along with other programming valued by fathers such as employment assistance. Implications for developing strategies for recruiting urban African American fathers to parenting programs are discussed.

A quarterly update on food- and waterborne diseases in Europe--summary of data for the third quarter of 2007

This paper highlights findings from the first quarterly report on food- and waterborne diseases produced by the European Centre for Disease Prevention and Control (ECDC). In the past such reports had been generated by Enter-net, a Europe-based international surveillance network for the enteric infections. The quarterly reports are an important surveillance tool for the network participants and other public health professionals to use in order to identify emerging trends and changes taking place in a shorter interval than one year.

An outbreak due to peanuts in their shell caused by Salmonella enterica serotypes Stanley and Newport--sharing molecular information to solve international outbreaks

Salmonellosis is a global problem caused by the international movement of foods and high incidence in exporting countries. In September 2001, in an outbreak investigation Australia isolated Salmonella Stanley from imported peanuts, which resulted in a wider investigation in Canada, England & Wales and Scotland. Patients infected with Salmonella serotypes known to be isolated from peanuts and reported to surveillance systems were interviewed to determine exposure histories. Tagged image file format (TIFF) images of pulsed-field gel electrophoresis (PFGE) patterns of Salmonella isolates were shared electronically amongst laboratories. Laboratories tested packets of 'Brand X' peanuts from various lots and product lines. In total, 97 cases of S. Stanley and 12 cases of S. Newport infection were found. Seventy-three per cent (71/97) of S. Stanley cases were in persons of Asian ethnicity. Twenty-eight per cent of cases recalled eating Brand X peanuts and a further 13% had peanuts in their house in the previous month or had eaten Asian-style peanuts. Laboratories isolated S. Stanley, S. Newport, S. Kottbus, S. Lexington and S. Unnamed from Brand X peanuts. Isolates of S. Stanley from peanuts and human patients were indistinguishable by PFGE. This international outbreak resulted from a product originating from one country affecting several others. Rapid sharing of electronic DNA images was a crucial factor in delineating the outbreak; multinational investigations would benefit from a harmonized approach.

Fluorescent amplified fragment length polymorphism genotyping of Salmonella Enteritidis: a method suitable for rapid outbreak recognition

OBJECTIVE

To perform fluorescent amplified fragment length polymorphism (FAFLP) analysis on phage type (PT) reference strains of Salmonella enterica subsp. enterica serotype Enteritidis (S. Enteritidis), and S. Enteritidis PT 6 and 6a recent clinical isolates to determine its usefulness for primary characterization of clinical S. Enteritidis isolates, and then to determine whether FAFLP is suitable for rapid characterization of strains in an outbreak situation.

METHODS

Twenty-five PT reference strains of S. Enteritidis and 20 S. Enteritidis PT 6 and 6a clinical isolates were subjected to FAFLP analysis using the selective primer combinations Eco + 0-Mse + T and Eco + 0-Mse + TA.

RESULTS

FAFLP successfully separated each one of the 25 S. Enteritidis PT strains into distinct profiles, while macrorestriction and PFGE using XbaI identified 20 pulsed-field profiles. FAFLP also resolved cases and outbreaks due to S. Enteritidis PTs 6 and 6a.

CONCLUSIONS

The resolving power of FAFLP was higher than that of PFGE. FAFLP is a highly discriminatory genotyping method and, in conjunction with phage typing for primary subdivision of S. Enteritidis, provides a rapid and powerful tool for strain differentiation, both for outbreak investigation and for epidemiologic surveillance.

The effects of road traffic accidents on driving behaviour

Questionnaires about the effects of accidents on subsequent driving behaviour were sent to 869 people admitted consecutively to a general hospital as a result of involvement in road traffic accidents 4-6 years previously. There were 418 (48 per cent) replies, 67 per cent of delivered questionnaires. One-fifth of the motorcyclists had stopped using a motorcycle. Nearly one-half the motorcyclists and vehicle drivers reported that they now drove more slowly and that they were more cautious. A considerable proportion of replies described emotional distress, avoidance and limitation of activities. Lack of confidence in driving was common immediately after the accident. After 4-6 years, one-third of respondents reported that they still suffered specific anxiety about the place of the accident and about situations similar to the accident. Many people were anxious about being passengers. The findings have implications for road safety, for the recognition and management of a common, and often disabling, clinical problem, and for the assessment of disabilities in medical reports for compensation proceedings.