The Maximal Entropy Measure of Fatou Boundaries

We look at the maximal entropy (MME) measure of the boundaries of connected components of the Fatou set of a rational map of degree greater than or equal to 2. We show that if there are infinitely many Fatou components, and if either the Julia set is disconnected or the map is hyperbolic, then there can be at most one Fatou component whose boundary has positive MME measure. We also replace hyperbolicity by the more general hypothesis of geometric finiteness

Students’ Perspective on Intrinsic Motivation to Learn: A Model to Guide Educators

The purpose of this qualitative study was to understand the collective perspective of what motivates students to exert effort and energy towards learning tasks in a classroom setting. To reach this goal, the researcher utilized a qualitative methodology, the Insider Perspective Approach, to take a deep look inside the classroom experience and examine the broad view of the students’ collective perspective. A model for situational motivation is presented suggesting factors that educators can manipulate to enhance students’ intrinsic motivation to learn: control, competence, active involvement, variety, curiosity, challenge, a sense of belonging, and honored voices. When teachers integrate these constructs as they plan activities and assignments, students’ intrinsic motivation to learn will be enhanced

Farmers, farm workers and work-related stress

This research explores the ways in which stress affects farming communities, how this has changed in recent years, and the degree to which work-related aspects of stress may be assuaged by support interventions. A qualitative case study research approach was employed to address these issues, involving 60 interviews in five locations across England and Wales.In examining farming stress, a distinction is made between its intrinsic, extrinsic and workrelated dimensions. Whileinterviewees tended to associate day-to-day worries and acute stress with farming’s intrinsic demands (such as disease and adverse weather conditions), external causes of tension (such as competition and regulation), together with worries about finances and family, were associated with more sustained anxieties. By contrast, work-related aspects of farming stress, such as workload issues and farming practices, involved a combination of physical and mental health effects.Notably, work-related and extrinsic dimensions of stress have increased in recent years in relation to organisational and policy shifts, price fluctuations, mounting paperwork demands, workload intensification, and changes in agricultural regulation. These have prompted an escalation in the aspects of their work that farming communities feel powerless to control, and represent a major area for policy intervention. Principal farmers displayed the most visible manifestations of stress, linked at once to the intrinsic, extrinsic and workrelated dimensions of their work. By contrast, family farm workers and labourers often lacked autonomy over the way they worked, and work-related aspects of stress concerning workload and organisation made up a greater part of their experience. Increased paperwork demands emerged as a major cause of stress among interviewees, particularly forfarmers and their wives, who struggled to balance these with traditional farming priorities. Differences between farmswere also influential in explaining stress. Livestock farming embodied intrinsic pressures relating to stock crises and the unpredictability of animals, but more recently has come under intense economic pressure, prompting a rationalisation of working practices. Arable farmers found the organisation of activities, such as harvesting and planting, in a context of reduced and increasingly contractual workforces particularly challenging. Mixed farmers faced the dual stresses of balancing work activities with conflicting timetables, and the paperwork demands of a complex portfolio of farming. Smaller farms were struggled with intensified workloads, while larger enterprises had to comply with the demands of more inspection regimes.Support agencies need to overcome the stigma attached to asking for help among farming communities and offer a rangeof responsive and proactive services. Locally based support was more likely to be used and trusted, although concernsabout client confidentiality might deter those most in need from seeking help. Where existing local networks wereestablished, there was a strong argument for providers to plug into these and work towards publicising their efforts to ensure that support is provided most effectively. Critically, support must be multidimensional, reflecting the wide range of stressors and their impacts among farming communities

Making a Difference?: The Effects of Teach for America in High School

Uses longitudinal data from North Carolina to estimate the effectiveness, in terms of gains in student test scores, of TFA teachers relative to traditional teachers. Focuses on math and science teachers in the first study of TFA effects in high schools

Researching Hard-to Reach Populations: Privileged Access Interviewers and Drug Using Parents

Accessing drug using populations is notoriously fraught with difficulties for researchers (Gurdin & Patterson, 1987; Griffiths, Gosspo & Strang, 1993; Renzetti & Lee, 1993; Spreen & Zwaagstra, 1994; Goode, 2000; Elliott et al., 2002). These difficulties are the result of a number of reasons. The main one being that drug use is often illicit and/or illegal which often leads to the stigmatization of drug users within the media and elsewhere and this may ultimately lead to their lives being 'concealed by a veil of ignorance' (Elliott et al., 2002: 172). When one adds to this the fact that the population in question may have even more reason to remain hidden, for example, that they are drug using parents who may wish to conceal their identity as either parent or as drug user, accessing them may be even more complicated for researchers, service providers and policy makers alike.Privileged Access Interviewers, Drug Using Parents

Crystal structure of human IPS-1/MAVS/VISA/Cardif caspase activation recruitment domain

Background: IPS-1/MAVS/VISA/Cardif is an adaptor protein that plays a crucial role in the induction of interferons in response to viral infection. In the initial stage of the intracellular antiviral response two RNA helicases, retinoic acid inducible gene-I (RIG-I) and melanoma differentiation-association gene 5 (MDA5), are independently able to bind viral RNA in the cytoplasm. The 62 kDa protein IPS-1/MAVS/VISA/Cardif contains an N-terminal caspase activation and recruitment (CARD) domain that associates with the CARD regions of RIG-I and MDA5, ultimately leading to the induction of type I interferons. As a first step towards understanding the molecular basis of this important adaptor protein we have undertaken structural studies of the IPS-1 MAVS/VISA/Cardif CARD region. Results: The crystal structure of human IPS-1/MAVS/VISA/Cardif CARD has been determined to 2.1 angstrom resolution. The protein was expressed and crystallized as a maltose-binding protein (MBP) fusion protein. The MBP and IPS-1 components each form a distinct domain within the structure. IPS-1/MAVS/VISA/Cardif CARD adopts a characteristic six-helix bundle with a Greek-key topology and, in common with a number of other known CARD structures, contains two major polar surfaces on opposite sides of the molecule. One face has a surface-exposed, disordered tryptophan residue that may explain the poor solubility of untagged expression constructs. Conclusion: The IPS-1/MAVS/VISA/Cardif CARD domain adopts the classic CARD fold with an asymmetric surface charge distribution that is typical of CARD domains involved in homotypic protein-protein interactions. The location of the two polar areas on IPS-1/MAVS/VISA/Cardif CARD suggest possible types of associations that this domain makes with the two CARD domains of MDA5 or RIG-I. The N-terminal CARD domains of RIG-I and MDA5 share greatest sequence similarity with IPS-1/MAVS/VISA/Cardif CARD and this has allowed modelling of their structures. These models show a very different charge profile for the equivalent surfaces compared to IPS-1/MAVS/VISA/Cardif CARD.Publisher PDFPeer reviewe