Genealogical constructions of population models

Representations of population models in terms of countable systems of particles are constructed, in which each particle has a `type', typically recording both spatial position and genetic type, and a level. For finite intensity models, the levels are distributed on $[0,\lambda ]$, whereas in the infinite intensity limit $\lambda\rightarrow\infty$, at each time $t$, the joint distribution of types and levels is conditionally Poisson, with mean measure $\Xi (t)\times \ell$ where $\ell$ denotes Lebesgue measure and $\Xi (t)$ is a measure-valued population process. The time-evolution of the levels captures the genealogies of the particles in the population. Key forces of ecology and genetics can be captured within this common framework. Models covered incorporate both individual and event based births and deaths, one-for-one replacement, immigration, independent `thinning' and independent or exchangeable spatial motion and mutation of individuals. Since birth and death probabilities can depend on type, they also include natural selection. The primary goal of the paper is to present particle-with-level or lookdown constructions for each of these elements of a population model. Then the elements can be combined to specify the desired model. In particular, a non-trivial extension of the spatial $\Lambda$-Fleming-Viot process is constructed

Does taking vitamin, mineral and fatty acid supplements prevent cognitive decline? A systematic review of randomized controlled trials

Background Observational studies have shown associations between nutritional status and cognition in later life but evidence from intervention studies is unclear. The present study systematically reviewed the evidence on the effect of nutrient supplementation on cognitive function in people aged ≥65 years. Methods Databases including MEDLINE and EMBASE were searched up to 1 September 2006. Randomized controlled trials using at least one kind of vitamin, mineral or omega-3 fatty acid, evaluating standardized neuropsychological test(s), were included. There were no restrictions on participants' baseline nutritional status or cognitive function. Quality assessment and data abstraction were conducted by one author and checked by another. Results Of 4229 articles retrieved, 22 trials (3442 participants) were identified. Many were small, short duration and of poor methodology. Only 16 out of 122 cognitive tests were significantly different between groups. A meta-analysis showed no significant effect of taking B vitamins or antioxidant vitamins on global cognitive function. There was insufficient evidence to evaluate the effect of omega-3 fatty acids on any cognitive domains. Conclusion There was little evidence of a beneficial effect from taking B vitamins or antioxidant supplements on global cognitive function in later life. Larger-scale randomized controlled trials of longer duration in selected age groups are needed.Institute of Applied Health Science, University of Aberdeen; Chief Scientist Office of the Scottish Government Health Directorates; Chief Scientist of the Scottish Government Health Directorate

Biological functions of CDK5 and potential CDK5 targeted clinical treatments.

Cyclin dependent kinases are proline-directed serine/threonine protein kinases that are traditionally activated upon association with a regulatory subunit. For most CDKs, activation by a cyclin occurs through association and phosphorylation of the CDK\u27s T-loop. CDK5 is unusual because it is not typically activated upon binding with a cyclin and does not require T-loop phosphorylation for activation, even though it has high amino acid sequence homology with other CDKs. While it was previously thought that CDK5 only interacted with p35 or p39 and their cleaved counterparts, Recent evidence suggests that CDK5 can interact with certain cylins, amongst other proteins, which modulate CDK5 activity levels. This review discusses recent findings of molecular interactions that regulate CDK5 activity and CDK5 associated pathways that are implicated in various diseases. Also covered herein is the growing body of evidence for CDK5 in contributing to the onset and progression of tumorigenesis

Pollination services in the UK: how important are honeybees?

Pollination services are known to provide substantial benefits to human populations and agriculture in particular. Although many species are known to provide pollination services, honeybees (Apis mellifera) are often assumed to provide the majority of these services to agriculture. Using data from a range of secondary sources, this study assesses the importance of insect pollinated crops at regional and national scales and investigates the capacity of honeybees to provide optimal pollination services to UK agriculture. The findings indicate that insect pollinated crops have become increasingly important in UK crop agriculture and, as of 2007, accounted for 20% of UK cropland and 19% of total farmgate crop value. Analysis of honeybee hive numbers indicates that current UK populations are only capable of supplying 34% of pollination service demands even under favourable assumptions, falling from 70% in 1984. In spite of this decline, insect pollinated crop yields have risen by an average of 54% since 1984, casting doubt on long held beliefs that honeybees provide the majority of pollination services. Future land use and crop production patterns may further increase the role of pollination services to UK agriculture, highlighting the importance of measures aimed at maintaining both wild and managed species

Intergenerational Transmission of Healthy Eating Behaviour and the Role of Household Income

This paper investigates the possibility of intergenerational transmission of unhealthy eating habits from parents to adult children. It uses the 2003 Scottish Health Survey and estimates the association between the present healthy eating behaviour of adult children and the past parental death from cardiovascular disease (CVD). It uses parental CVD death as an adverse health signal which may cause a healthy eating compensatory response in adult children. This response is due to increased chances and perception of genetic predisposition of adult children as well as an indicator for parental past unhealthy eating habits which may have been passed onto the adult children. Regression analysis suggests that paternal history has no impact on either sons or daughters, and maternal history influences negatively the eating behaviour of daughters only. Unhealthy eating intergenerational transmission appears to be more intense amongst lower household income individuals.intergenerational transmission, healthy eating, household income, cardiovascular disease, public health, gender

A cost comparison of traditional drainage and SUDS in Scotland

The Dunfermline Eastern Expansion (DEX) is a 350 ha mixed development which commenced in 1996. Downstream water quality and flooding issues necessitated a holistic approach to drainage planning and the site has become a European showcase for the application of Sustainable Urban Drainage Systems (SUDS). However, there is minimal data available regarding the real costs of operating and maintaining SUDS to ensure they continue to perform as per their design function. This remains one of the primary barriers to the uptake and adoption of SUDS. This paper reports on what is understood to be the only study in the UK where actual costs of constructing and maintaining SUDS have been compared to an equivalent traditional drainage solution. To compare SUDS costs with traditional drainage, capital and maintenance costs of underground storage chambers of analogous storage volumes were estimated. A whole life costing methodology was then applied to data gathered. The main objective was to produce a reliable and robust cost comparison between SUDS and traditional drainage. The cost analysis is supportive of SUDS and indicates that well designed and maintained SUDS are more cost effective to construct, and cost less to maintain than traditional drainage solutions which are unable to meet the environmental requirements of current legislation

Examining the Effects of AAC Intervention on Oral Language in Children with Autism Spectrum Disorders: A Systematic Review

This systematic review researched the efficacy of augmentative and alternative communication (AAC) in increasing oral communication in children with Autism Spectrum Disorder (ASD). It may be used to inform best practice when working with children with ASD. The search strategy reviewed medical, social science, and communication databases. Inclusionary criteria consisted of peer-reviewed, quantitative research published after 2007 regarding children with ASD under age 18. The included studies used AAC interventions and measured spoken language outcomes. After conducting an initial database search with these criteria, a manual search was performed using references from the found articles. Results varied across studies. Although the trend demonstrates increases in verbal language with AAC intervention, few studies show statistically significant outcomes. The studies indicate that additional factors, such as verbal communication at baseline, may affect outcomes. AAC use did not decrease verbal language. Limitations included few randomized control trial designs, few study replications, and varied outcome measures. Based on the studies analyzed, implementation of AAC may increase the number of communicative acts, but may not reliably increase verbal language. Further research is needed to understand the most effective implementation of AAC intervention to increase verbal language. Higher quality research in the form of randomized control trials, and the replication of studies to confirm results is necessary to inform evidence-based practice. The findings are consistent with those of previous systematic reviews and meta analyses. Future considerations should include type of AAC, communicative act being measured, longitudinal studies, and increased use of formal measures.https://scholarworks.uvm.edu/csdms/1002/thumbnail.jp

Generation of a poor prognostic chronic lymphocytic leukemia-like disease model: PKC subversion induces up-regulation of PKC II expression in B lymphocytes

Overwhelming evidence identifies the microenvironment as a critical factor in the development and progression of chronic lymphocytic leukemia, underlining the importance of developing suitable translational models to study the pathogenesis of the disease. We previously established that stable expression of kinase dead protein kinase C alpha in hematopoietic progenitor cells resulted in the development of a chronic lymphocytic leukemia-like disease in mice. Here we demonstrate that this chronic lymphocytic leukemia model resembles the more aggressive subset of chronic lymphocytic leukemia, expressing predominantly unmutated immunoglobulin heavy chain genes, with upregulated tyrosine kinase ZAP-70 expression and elevated ERK-MAPK-mTor signaling, resulting in enhanced proliferation and increased tumor load in lymphoid organs. Reduced function of PKCα leads to an up-regulation of PKCβII expression, which is also associated with a poor prognostic subset of human chronic lymphocytic leukemia samples. Treatment of chronic lymphocytic leukemia-like cells with the selective PKCβ inhibitor enzastaurin caused cell cycle arrest and apoptosis both in vitro and in vivo, and a reduction in the leukemic burden in vivo. These results demonstrate the importance of PKCβII in chronic lymphocytic leukemia-like disease progression and suggest a role for PKCα subversion in creating permissive conditions for leukemogenesis

Anthropogenic and Natural Determinants of the Population of a Sensitive Species: Sage Grouse in Nevada

This paper uses Nevada data to conduct regression analyses of the relationship between sage grouse (Centrocercus urophasianus) population sizes and potential causal factors. This is policy-relevant because of current petitions for listing this species under the Endangered Species Act. A key feature is that, although monitoring of sage grouse has occurred for many decades, data collection methods and level of monitoring effort have not been consistent. To account for this feature we use, as dependent variables, standardized measures such as population counts and harvest (hunting success) per unit of effort. Preliminary findings suggest that such measures have been particularly sensitive to whether or not humans used strychnine for predator control, with normalized measures of grouse populations higher in years when strychnine was employed. Our results also suggest a positive association between the number of cattle on the range and normalized measures of grouse population. This is a controversial finding as some studies suggest a negative impact of cattle grazing on grouse. Our data do not include indications of the timing and precise nature of grazing practices and so should be interpreted with caution.population viability analysis and endangered species, factors affecting decline of sage grouse