The Relationship between Childhood Obesity, Low Socioeconomic Status, and Race/Ethnicity: Lessons from Massachusetts

Background: Previous studies have shown race/ethnicity, particularly African American and/or Hispanic status, to be a predictor of overweight/obese status in children. However, these studies have failed to adjust for low socioeconomic status (SES). This study assessed whether race/ethnicity remained an independent predictor of childhood obesity when accounting for variations in SES (low-income) among communities in Massachusetts. Methods: This study was based on 2009 summarized data from 68 Massachusetts school districts with 111,799 students in grades 1, 4, 7, and 10. We studied the relationship between the rate of overweight/obese students (mean?=?0.32; range?=?0.10?0.46), the rate of African American and Hispanic students (mean?=?0.17; range?=?0.00?0.90), and the rate of low-income students (mean?=?0.27; range?=?0.02?0.87) in two and three dimensions. The main effect of the race/ethnicity rate, the low-income rate, and their interaction on the overweight and obese rate was investigated by multiple regression modeling. Results: Low-income was highly associated with overweight/obese status (p?Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140341/1/chi.2015.0029.pd

Behavioural and physiological correlates of impulsivity in the domestic dog (Canis familiaris)

Impulsivity is a trait related to inhibitory control which is expressed in a range of behaviours. Impulsive individuals show a decreased ability to tolerate delay of reinforcement, and more impulsive behaviour has been linked to decreased levels of serotonin and dopamine in a number of species. In domestic dogs, impulsivity is implicated in problem behaviours that result from a lack of self control, but currently there are no published studies that assess behavioural and physiological measures of impulsivity in relation to this trait. Impulsivity scores were calculated for 41 dogs using an owner-report assessment, the Dog Impulsivity Assessment Scale (DIAS). Twenty-three of these subjects completed an operant choice task based on a delayed reward paradigm, to assess their tolerance to delay of reinforcement. High Pressure Liquid Chromatography (HPLC) with Fluorometric Detection was used to detect levels of the metabolites of serotonin (5-HIAA) and dopamine (HVA) in the urine of 17 of the subjects. Higher impulsivity scores were found to be significantly correlated with more impulsive behaviour (reduced tolerance to delay of reinforcement) in the behaviour tests and lower levels of urinary 5-HIAA and 5-HIAA/HVA ratio. The results demonstrate convergent validity between impulsivity (as assessed by the DIAS) and behavioural and physiological parameters

Ricci-flat Metrics with U(1) Action and the Dirichlet Boundary-value Problem in Riemannian Quantum Gravity and Isoperimetric Inequalities

The Dirichlet boundary-value problem and isoperimetric inequalities for positive definite regular solutions of the vacuum Einstein equations are studied in arbitrary dimensions for the class of metrics with boundaries admitting a U(1) action. We show that in the case of non-trivial bundles Taub-Bolt infillings are double-valued whereas Taub-Nut and Eguchi-Hanson infillings are unique. In the case of trivial bundles, there are two Schwarzschild infillings in arbitrary dimensions. The condition of whether a particular type of filling in is possible can be expressed as a limitation on squashing through a functional dependence on dimension in each case. The case of the Eguchi-Hanson metric is solved in arbitrary dimension. The Taub-Nut and the Taub-Bolt are solved in four dimensions and methods for arbitrary dimension are delineated. For the case of Schwarzschild, analytic formulae for the two infilling black hole masses in arbitrary dimension have been obtained. This should facilitate the study of black hole dynamics/thermodynamics in higher dimensions. We found that all infilling solutions are convex. Thus convexity of the boundary does not guarantee uniqueness of the infilling. Isoperimetric inequalities involving the volume of the boundary and the volume of the infilling solutions are then investigated. In particular, the analogues of Minkowski's celebrated inequality in flat space are found and discussed providing insight into the geometric nature of these Ricci-flat spaces.Comment: 40 pages, 3 figure

A Quarter Century Exploring Tetrahymena *

In reviewing 25 years of work on Tetrahymena , the author describes early difficulties experienced by himself and others in developing a chemically-defined medium and in defining the taxonomy of T. pyriformis. With identification of its essential requirements, a variety of nutritional studies revealed the close resemblance between the metabolic pathways of this ciliate and those of the chick and rat. This suggested studies on the effects of gamma radiation and the effect of antibiotics. Attention then turned to the puzzle of the absence of conjugation in all strains of T. pyriformis then maintained in laboratories. The observation that these strains were all amicronucleate led to the discovery of mating types (with D. F. Gruchy). This brought up the problem of what constitutes a species and how it might be solved in T. pyriformis where clearly defined groups are set off from other similar groups (varieties) by a breeding barrier. Another problem is whether a life cycle exists in this ciliate and if so, the role amicronucleate strains play in this cycle. The origin and obvious evolutionary success of these “genetically dead” strains are other problems that are considered. The search for nutritional markers for genetic experiments inspired large-scale collections, including some from tropical habitats. Strains were found which differed in serine and pyridoxine requirements. Genetic analysis was hindered by the high lethality following conjugation, unsatisfactory mating behavior in some clones, and the complete absence of autogamy, the latter making it difficult to obtain homozygous clones. The use of x-radiation yielded haploid individuals; when these were mated with diploid clones the resulting haploid progeny proved that the genes controlling mating type and pyridoxine synthesis resided in the micronucleus. Genetic analysis of the serine and pyridoxine mutants supports the idea that T. pyriformis is more of an outbreeder than an inbreeder. Left for the future is an extension of our knowledge of the breeding system of T. pyriformis and ultimately to examine critically the factors responsible for the success of this ubiquitous ciliate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71977/1/j.1550-7408.1959.tb03918.x.pd

Genetic Diversity, Recombination, and Divergence in Animal Associated Penicillium dipodomyis

Penicillium dipodomyis is thought to be an exclusively asexual fungus associated with Kangaroo Rats, Dipodomys species, and is unique among Penicillium species in growing at 37°C but producing no known toxins. Lack of recombination within P. dipodomyis would result in limited adaptive flexibility but possibly enhance local adaptation and host selection via maintenance of favourable genotypes. Here, analysis of DNA sequence data from five protein-coding genes shows that recombination occurs within P. dipodomyis on a small spatial scale. Furthermore, detection of mating-type alleles supports outcrossing and a sexual cycle in P. dipodomyis. P. dipodomyis was a weaker competitor in in vitro assays with other Penicillium species found in association with Kanagaroo rats. Bayesian species level analysis suggests that the P. dipodomyis lineage diverged from closely related species also found in cheek pouches of Kangaroo Rats and their stored seeds about 11 million years ago, a similar divergence time as Dipodomys from its sister rodent taxa

Temporal Networks

A great variety of systems in nature, society and technology -- from the web of sexual contacts to the Internet, from the nervous system to power grids -- can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via email, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g., the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks

Dynamical Patterns of Cattle Trade Movements

Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions

Dynamical Patterns of Cattle Trade Movements

Despite their importance for the spread of zoonotic diseases, our understanding of the dynamical aspects characterizing the movements of farmed animal populations remains limited as these systems are traditionally studied as static objects and through simplified approximations. By leveraging on the network science approach, here we are able for the first time to fully analyze the longitudinal dataset of Italian cattle movements that reports the mobility of individual animals among farms on a daily basis. The complexity and inter-relations between topology, function and dynamical nature of the system are characterized at different spatial and time resolutions, in order to uncover patterns and vulnerabilities fundamental for the definition of targeted prevention and control measures for zoonotic diseases. Results show how the stationarity of statistical distributions coexists with a strong and non-trivial evolutionary dynamics at the node and link levels, on all timescales. Traditional static views of the displacement network hide important patterns of structural changes affecting nodes' centrality and farms' spreading potential, thus limiting the efficiency of interventions based on partial longitudinal information. By fully taking into account the longitudinal dimension, we propose a novel definition of dynamical motifs that is able to uncover the presence of a temporal arrow describing the evolution of the system and the causality patterns of its displacements, shedding light on mechanisms that may play a crucial role in the definition of preventive actions