A Comment on Budach's Mouse-in-an-Octant Problem

Budach's Mouse-in-an-Octant Problem (attributed to Lothar Budach in a 1980 article by van Emde Boas and Karpinski) concerns the behaviour of a very simple finite-state machine ("the mouse") moving on the integer two-dimensional grid. Its decidability is apparently still open. This note sketches a proof that an extended version of the problem (a super-mouse) is undecidable.Comment: 3 pages, 2 bibliographic reference

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

Neuromuscular performance capabilities, including those measured by evoked responses, may be adversely affected by fatigue; however, the capability of the neuromuscular system to initiate muscle force rapidly under these circumstances is yet to be established. Sex-differences in the acute responses of neuromuscular performance to exercise stress may be linked to evidence that females are much more vulnerable to ACL injury than males. Optimal functioning of the knee flexors is paramount to the dynamic stabilisation of the knee joint, therefore the aim of this investigation was to examine the effects of acute maximal intensity fatiguing exercise on the voluntary and magnetically-evoked electromechanical delay in the knee flexors of males and females. Knee flexor volitional and magnetically-evoked neuromuscular performance was assessed in seven male and nine females prior to and immediately after: (i) an intervention condition comprising a fatigue trial of 30-seconds maximal static exercise of the knee flexors, (ii) a control condition consisting of no exercise. The results showed that the fatigue intervention was associated with a substantive reduction in volitional peak force (PFV) that was greater in males compared to females (15.0%, 10.2%, respectively, p < 0.01) and impairment to volitional electromechanical delay (EMDV) in females exclusively (19.3%, p < 0.05). Similar improvements in magnetically-evoked electromechanical delay in males and females following fatigue (21%, p < 0.001), however, may suggest a vital facilitatory mechanism to overcome the effects of impaired voluntary capabilities, and a faster neuromuscular response that can be deployed during critical times to protect the joint system

Intervention strategies for children and adolescent with disorders: from intrapsychic to transactional perspective

A large amount of studies and clinical evidence document the importance of infancy and early childhood influences on long term developmental trajectories toward mental health or psychopathology (Sameroff, 2000, 2010). Without healthy, productive adults no culture could continue to be successful. This concern is the main motivation for society to support child development research. Although the academic interests of contemporary developmental researchers range widely in cognitive and socialemotional domains, the political justification for supporting such studies is that they will lead to the understanding and ultimate prevention of behavioural problems that are costly to society. With these motivations and support, there have been major advances in our understanding of the intellectual, emotional, and social behaviour of children, adolescents and adults. This progress has forced conceptual reorientations from a unidirectionalunderstanding of development (e.g., parents affect children and not vice versa) toward a bidirectional conceptualization of development. Childrenare now assumed to affect and even select their environments as much as their environments affect their behaviour. Indeed, key among many of the most influential developmental theories in the past several decades is the assumption that children have bidirectional, or reciprocal, relationships with their environments (Bandura, 1977; Bronfenbrenner, 1979). To date, it is widely accepted that children’s healthy development is shaped by complex transactional processes among a variety of risk and protective factors, with cumulative risk factors increasing the prediction of emotional and behavioural problems (Anda et al., 2007; Rutter &amp; Sroufe, 2000; Sameroff, 2000). Risk and protective factors include individual child characteristics such as genetic and constitutional propensities and cognitive strengths and vulnerabilities; parent characteristics such as mental health, education level, sense of efficacy, and resourcefulness; family factors such as quality of the parent-child relationship, emotional climate, and marital quality; community connectedness factors such as parental social support, social resources, and children’s peer relationships; and neighbourhood factors such as availability of resources, adequacy of housing, and levels of crime and violence (Sameroff &amp; Fiese, 2000). The predictive value of these factors across many studies led to the development of transactional-bioecological models that attempt to conceptualize the relative contributions of proximal and distal risk and protective factors to children’s developmental outcome (Bronfenbrenner &amp; Morris, 2006). In 1975, Sameroff and Chandler proposed the transactional model. This theoretical framework has become central to understanding the interplay between nature and nurture in explaining the development of positive and negative outcomes for children. The transactional model is a model of qualitative change. Sameroff asserted that the transactional model concerned qualitative rather than incremental change and that the underlying process was dialectical rather mechanistic in nature. The aim of this chapter is to explore this theoretical framework and its intervention strategies. In the first part, the transactional model will be described after a brief summary that will illustrate the transition from intrapsychic to transactional perspective. In the second part, intervention strategies for children and adolescent will be described. The attention of research on environmental risk and protective factors has fostered a more comprehensive understanding of what is necessary to improve the cognitive and social-emotional welfare of children and adolescents

Immunity and Simplicity for Exact Counting and Other Counting Classes

Ko [RAIRO 24, 1990] and Bruschi [TCS 102, 1992] showed that in some relativized world, PSPACE (in fact, ParityP) contains a set that is immune to the polynomial hierarchy (PH). In this paper, we study and settle the question of (relativized) separations with immunity for PH and the counting classes PP, C_{=}P, and ParityP in all possible pairwise combinations. Our main result is that there is an oracle A relative to which C_{=}P contains a set that is immune to BPP^{ParityP}. In particular, this C_{=}P^A set is immune to PH^{A} and ParityP^{A}. Strengthening results of Tor\'{a}n [J.ACM 38, 1991] and Green [IPL 37, 1991], we also show that, in suitable relativizations, NP contains a C_{=}P-immune set, and ParityP contains a PP^{PH}-immune set. This implies the existence of a C_{=}P^{B}-simple set for some oracle B, which extends results of Balc\'{a}zar et al. [SIAM J.Comp. 14, 1985; RAIRO 22, 1988] and provides the first example of a simple set in a class not known to be contained in PH. Our proof technique requires a circuit lower bound for ``exact counting'' that is derived from Razborov's [Mat. Zametki 41, 1987] lower bound for majority.Comment: 20 page