Parasitic chytrids could promote copepod survival by mediating material transfer from inedible diatoms

Diatoms form large spring blooms in lakes and oceans, providing fuel for higher trophic levels at the start of the growing season. Some of the diatom blooms, however, are not grazed by filter-feeding zooplankton like Daphnia due to their large size. Several of these large diatoms are susceptible to chytrid infections. Zoospores of chytrids appeared to be excellent food for Daphnia, both in terms of size, shape, and quality (PUFAs and cholesterol). Thus, zoospores of chytrids can bridge the gap between inedible diatoms and Daphnia. In order to examine the effects of diatoms and chytrids on the survival of copepods, we performed one grazing and one survival experiment. The grazing experiment revealed that the diatom, Asterionella formosa, was not grazed by the copepod, Eudiaptomus gracilis, even after being infected by the chytrid Zygorhizidium planktonicum. However, carbon and nitrogen concentrations were significantly reduced by E. gracilis only when A. formosa was infected by Z. planktonicum, indicating that the chytrids might facilitate material transfer from inedible diatoms to the copepods. The survival experiment revealed that E. gracilis lived shorter with A. formosa than with the cryptophyta Cryptomonas pyrenoidifera. However, the survival of E. gracilis increased significantly in the treatment where A. formosa cells were infected by Z. planktonicum. Since E. gracilis could not graze A. formosa cells due to their large colonial forms, E. gracilis may acquire nutrients by grazing on the zoospores, and were so able to survive in the presence of the A. formosa. This provides new insights into the role of parasitic fungi in aquatic food webs, where chytrids may improve copepod survival during diatom blooms.

"Do what you can with a happy heart": a longitudinal study of patient and family members' lived experiences of physical activity post-myocardial infarction.

PURPOSE: Physical activity (PA) post-myocardial infarction (MI) can reduce risk of reoccurrence and mortality. Yet uptake of PA through cardiac rehabilitation (CR) is poor, and little is known about the long-term PA behaviour of cardiac patients. This study aimed to explore the lived experiences of patients' engagement with PA post-MI, together with the experiences of their family. METHODS: Longitudinal interviews with six family-dyads were conducted which drew on interpretative phenomenology to understand the lived experiences of PA for post-MI patients and family members. RESULTS: Participants described a journey that involved leaving "normality" (doing what PA they wanted and when) and transitioning to a new "normality" (being active within post-MI parameters). This journey was expressed through feelings of "I can't do what I was doing before," "finding my way," and "accepting this way". CONCLUSION: The role of family within the patient's journey was complex, with PA identity, beliefs, and fear of MI re-occurrence influencing PA support both positively and negatively. PA engagement post-MI is a dynamic and interactive process within which the family can have an important influence.IMPLICATIONS FOR REHABILITATIONThe process of (re-)engaging in physical activity post-myocardial infarction involves a complex journey towards acceptance of a new "normality".Family play an important role in regulating and supporting patients' physical activity during the rehabilitation process.Promoting positive health beliefs and helping families understand what, how and when patients should be physically active may optimise the rehabilitation journey for post-myocardial infarction patients

Family support for physical activity post-myocardial infarction: a qualitative study exploring the perceptions of cardiac rehabilitation practitioners.

Physical activity post-myocardial infarction has numerous health benefits, yet uptake through cardiac rehabilitation is poor. Whilst family support can facilitate patients' recovery, little is known about the role family may play in supporting physical activity for post-myocardial infarction patients. This qualitative study used semi-structured interviews with fourteen cardiac rehabilitation practitioners to explore their perceptions about the role of the family in supporting post-myocardial infarction patients' physical activity. Data were transcribed verbatim and analysed thematically. Three familial roles were identified, 'family as a second pair of ears', 'family as physical activity regulators' and 'family as social support'. A fourth theme, 'factors that influence family support' described how family health beliefs and perceptions could influence the physical activity support provided. Practitioner perceptions suggest families play an important role in post-myocardial infarction patients' physical activity, that is enhanced when families personally value physical activity. Integrating the family into cardiac rehabilitation may help facilitate physical activity-related interactions and promote positive engagement for patients

Optimal measurement of visual motion across spatial and temporal scales

Sensory systems use limited resources to mediate the perception of a great variety of objects and events. Here a normative framework is presented for exploring how the problem of efficient allocation of resources can be solved in visual perception. Starting with a basic property of every measurement, captured by Gabor's uncertainty relation about the location and frequency content of signals, prescriptions are developed for optimal allocation of sensors for reliable perception of visual motion. This study reveals that a large-scale characteristic of human vision (the spatiotemporal contrast sensitivity function) is similar to the optimal prescription, and it suggests that some previously puzzling phenomena of visual sensitivity, adaptation, and perceptual organization have simple principled explanations.Comment: 28 pages, 10 figures, 2 appendices; in press in Favorskaya MN and Jain LC (Eds), Computer Vision in Advanced Control Systems using Conventional and Intelligent Paradigms, Intelligent Systems Reference Library, Springer-Verlag, Berli

Incidence and drug treatment of emotional distress after cancer diagnosis : a matched primary care case-control study

Notes This work is published under the standard license to publish agreement. After 12 months the work will become freely available and the license terms will switch to a Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License.Peer reviewedPublisher PD

Barriers and facilitators to health care professionals discussing child weight with parents: A meta-synthesis of qualitative studies

Introduction: Childhood obesity is one of the most serious global public health challenges. However, obesity and its consequences are largely preventable. As parents play an important role in their children’s weight-related behaviours, good communication between parents and Health Care Professionals (HCPs) is essential. This systematic review provides a meta-synthesis of qualitative studies exploring the barriers and facilitators experienced by HCPs when discussing child weight with parents. Methods: Searches were conducted using the following databases; Medline (OVID), Psych INFO (OVID), EMBASE (OVID), Web of Knowledge and CINHAL. 13 full-text qualitative studies published in English language journals since 1985 were included. Included studies collected data from HCPs (e.g. nurses, doctors, dieticians, psychologists and clinical managers) concerning their experiences of discussing child weight-related issues with parents. An inductive thematic analysis was employed to synthesise findings. Findings: Emerging sub themes were categorised using a socio-ecological framework into intra/inter-personal factors, organisational factors and societal factors. Perceived barriers and facilitators most commonly related to intra/inter-personal level factors i.e. relating to staff factors, parental factors or professional-parent interactions. HCPs also attributed a number of barriers, but not facilitators, at the organisational and societal levels. Conclusion: The findings of this review may help to inform the development of future weight-related communication interventions. Whilst intra/inter-personal interventions may go some way to improving health care practice, it is crucial that all stakeholders consider the wider organisational and societal context in which these interactions take place

Factors influencing patient uptake of an exercise referral scheme: a qualitative study.

Exercise referral schemes aim to increase physical activity amongst inactive individuals with or at risk of long-term health conditions. Yet many patients referred to these schemes (by health professionals) fail to take up the exercise opportunities on offer. Understanding factors influencing uptake to exercise referral schemes may help improve future attendance. Using the Socio-Ecological Model as a framework, this qualitative study aimed to explore factors influencing uptake to an exercise referral scheme based in the North West of England. Semi-structured interviews were conducted with referred patients (n = 38) about their reasons for referral, interactions with referring health professionals, events following referral and ideas to improve future uptake. Data were analysed thematically and mapped onto the constructs of the Socio-Ecological Model. Factors reported to influence uptake included intrapersonal (past PA experiences, motivation, competing priorities), interpersonal (scheme explanations, support) and organizational influences (scheme promotion, communication between service, cost). Whilst several intrapersonal-level factors influenced patient decisions to uptake the exercise referral scheme, modifiable interpersonal and organizational factors were identified as potential targets for intervention. Recommendations are made for improving awareness of exercise referral schemes and for enhancing communication between referring practitioners, patients and referral scheme staff

Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions

The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions

Massless D-strings and moduli stabilization in type I cosmology

We consider the cosmological evolution induced by the free energy F of a gas of maximally supersymmetric heterotic strings at finite temperature and weak coupling in dimension D>=4. We show that F, which plays the role of an effective potential, has minima associated to enhanced gauge symmetries, where all internal moduli can be attracted and dynamically stabilized. Using the fact that the heterotic/type I S-duality remains valid at finite temperature and can be applied at each instant of a quasi-static evolution, we find in the dual type I cosmology that all internal NS-NS and RR moduli in the closed string sector and the Wilson lines in the open string sector can be stabilized. For the special case of D=6, the internal volume modulus remains a flat direction, while the dilaton is stabilized. An essential role is played by light D-string modes wrapping the internal manifold and whose contribution to the free energy cannot be omitted, even when the type I string is at weak coupling. As a result, the order of magnitude of the internal radii expectation values on the type I side is (lambda_I alpha')^{1/2}, where lambda_I is the ten-dimensional string coupling. The non-perturbative corrections to the type I free energy can alternatively be described as effects of "thermal E1-instantons", whose worldsheets wrap the compact Euclidean time cycle.Comment: 39 pages, 1 figur