The Ketogenic Diet: An Answer for Autism?

Lacking substantial evidence regarding its genetic identity, autism spectrum disorder (ASD) is a remarkably misunderstood condition with limited options for effective treatment. As the prevalence of patients with ASD increases, medical professionals continue to search for a solution. Could the ketogenic diet, a high fat, low carbohydrate nutrition plan, provide the relief that ASD patients are searching for

The validity of the Youth Physical Activity Questionnaire in 12-13 year old Scottish adolescents

Background: The development of accurate methods to measure health-behaviours forms an integral component in behavioural epidemiology. Population surveillance of physical activity often relies on self/proxy reported questionnaires due to cost and relative ease of administration. The aim of this study was to examine the criterion validity and measurement agreement between the Youth Physical Activity Questionnaire (YPAQ) and accelerometry before being included in a Scotland-wide study. Methods: Forty four participants (12–13 years old; 61% girls) completed the YPAQ following 7 days wearing the Actigraph GT3X+. Mean moderate-to-vigorous physical activity (MVPA) per day was derived from YPAQ and accelerometer and validity was assessed using Spearman's correlation; Bland-Altman plots examined absolute agreement between methods. Results: Pearson's and Spearman’s correlations between YPAQ and accelerometer were r = 0.47 and rs = 0.39 (p<0.01) respectively. The YPAQ over reported mean MVPA by 25.6 ± 50.2 minutes (95% CI 10.4-40.9 minutes; p <0.001), with 95% limits of agreement of −72.69 minutes and + 123.99 minutes. Evidence of underreporting at lower levels of activity and over reporting at higher levels of activity was evident (Pearson's r=0.81), in addition to heteroscedasticity, where variances increased as MVPA increased. Conclusions: Although a moderate correlation between the two methods was apparent, the YPAQ should not be used interchangeably with accelerometry. The YPAQ does demonstrate a reasonable ability to rank MVPA, although it tends to under-report lower levels and over-report higher levels. This, and other administering factors, should be taken into consideration if being used for group or individual level analyses

Chemical reaction systems with toric steady states

Mass-action chemical reaction systems are frequently used in Computational Biology. The corresponding polynomial dynamical systems are often large (consisting of tens or even hundreds of ordinary differential equations) and poorly parametrized (due to noisy measurement data and a small number of data points and repetitions). Therefore, it is often difficult to establish the existence of (positive) steady states or to determine whether more complicated phenomena such as multistationarity exist. If, however, the steady state ideal of the system is a binomial ideal, then we show that these questions can be answered easily. The focus of this work is on systems with this property, and we say that such systems have toric steady states. Our main result gives sufficient conditions for a chemical reaction system to have toric steady states. Furthermore, we analyze the capacity of such a system to exhibit positive steady states and multistationarity. Examples of systems with toric steady states include weakly-reversible zero-deficiency chemical reaction systems. An important application of our work concerns the networks that describe the multisite phosphorylation of a protein by a kinase/phosphatase pair in a sequential and distributive mechanism

The Development of an Insect Succession Model Suitable for Time-Since-Death Statistics

For academic carrion insect succession studies to be applicable to forensic casework, the study must provide statistically defensible postmortem interval (PMI) estimates. Multiple statistical approaches have been used to describe insect succession, but no study to date has been able to determine a confidence interval about a succession based PMI estimate. The ability to reject PMI values, and thereby create a confidence interval is determined by statistical power, of which sample size is a positive correlate. A proposed model established prospective sample sizes for desired levels of statistical power, indicating a target sample size of ~50 carcasses for estimating PMI based on two carrion insect species (LaMotte and Wells 2000). A surrogate for human decomposition has been identified, the domestic pig, yet studies to date have failed to include more than 5 carcasses in a single treatment group. This lack of replication has lead to strictly observational findings that are unsuitable for forensic use. As replication of carcasses increases, in an attempt to generate a suitable reference insect succession dataset, additional obstacles are encountered. Constraints of time and space, as well as development of an appropriate species list and sampling procedure are of specific concern. Throughout a century of research concerning insect succession on carrion, issues central to development of large datatsets, including the effect of year, fine-scale spatial discrepancies, repeated sampling and intercarcass distance, remain largely unknown.;The use of temperature to describe succession is an additional area of succession research critical to casework application. Because temperature directly affects decomposition rates, insect development rates and insect activity, succession data collected across time and space (potentially experiencing differing temperature histories) may most accurately be described using a physiological time measure as compared to an absolute time measure. Further, succession described in physiological time may be more accurate for application to a case that occurred at a different time and location than the reference dataset. The proposed research aims to create a succession dataset that is suitable for statistical analysis and estimation of time since death by: (1) investigating current sampling methods as well as the assumption that succession is consistent among year and small-scale variation in location, (2) determination of minimum intercarcass distance to ensure independence of carcasses, (3) identifying candidate insect species appropriate for analytical methods prescribed by LaMotte and Wells (2000), and (4) assessing accuracy of PMI estimates using an absolute and physiological time measure