Cognition in Rodents

Cognition is a loosely defined term with divergent meanings in different disciplines and species. In human psychology, ‘cognition’ is often used in reference to concepts such as ‘mind’ or ‘higher mental functions’. However, in more general terms, ‘cognition’ is regularly used to refer to all manner of information organization by the brain: from collection, to processing, to storage and recognition or recall. Whereas ‘cognition’ would seem to permeate all mental functions, including subjective perception and innate responses, ‘cognitive ability’ has a slightly more specific connotation – something more akin to intelligence or information-processing ability. Thus, ‘cognition’ deals with mental process structure and ‘cognitive abilities’ with natural variations impinging upon functioning at the higher end of that structure. Although the term ‘cognition’ sometimes subsumes or substitutes ‘cognitive ability’ in the literature, understanding this methodological distinction allows us to read across the two fields without the misunderstandings that classical cognitive psychologists have sometimes shown for cognitive ability research

A biophysical model of prokaryotic diversity in geothermal hot springs

Recent field investigations of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems, with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than the expected single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution field data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. Further, we present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed diversity of different strains of the photosynthetic bacteria. It also reproduces the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms

Matching microscopic and macroscopic responses in glasses

We first reproduce on the Janus and Janus II computers a milestone experiment that measures the spin-glass coherence length through the lowering of free-energy barriers induced by the Zeeman effect. Secondly we determine the scaling behavior that allows a quantitative analysis of a new experiment reported in the companion Letter [S. Guchhait and R. Orbach, Phys. Rev. Lett. 118, 157203 (2017)]. The value of the coherence length estimated through the analysis of microscopic correlation functions turns out to be quantitatively consistent with its measurement through macroscopic response functions. Further, non-linear susceptibilities, recently measured in glass-forming liquids, scale as powers of the same microscopic length.Comment: 6 pages, 4 figure

The Mpemba effect in spin glasses is a persistent memory effect

The Mpemba effect occurs when a hot system cools faster than an initially colder one, when both are refrigerated in the same thermal reservoir. Using the custom built supercomputer Janus II, we study the Mpemba effect in spin glasses and show that it is a non-equilibrium process, governed by the coherence length \xi of the system. The effect occurs when the bath temperature lies in the glassy phase, but it is not necessary for the thermal protocol to cross the critical temperature. In fact, the Mpemba effect follows from a strong relationship between the internal energy and \xi that turns out to be a sure-tell sign of being in the glassy phase. Thus, the Mpemba effect presents itself as an intriguing new avenue for the experimental study of the coherence length in supercooled liquids and other glass formers.Comment: Version accepted for publication in PNAS. 6 pages, 7 figure

The three dimensional Ising spin glass in an external magnetic field: the role of the silent majority

We perform equilibrium parallel-tempering simulations of the 3D Ising Edwards-Anderson spin glass in a field. A traditional analysis shows no signs of a phase transition. Yet, we encounter dramatic fluctuations in the behaviour of the model: Averages over all the data only describe the behaviour of a small fraction of it. Therefore we develop a new approach to study the equilibrium behaviour of the system, by classifying the measurements as a function of a conditioning variate. We propose a finite-size scaling analysis based on the probability distribution function of the conditioning variate, which may accelerate the convergence to the thermodynamic limit. In this way, we find a non-trivial spectrum of behaviours, where a part of the measurements behaves as the average, while the majority of them shows signs of scale invariance. As a result, we can estimate the temperature interval where the phase transition in a field ought to lie, if it exists. Although this would-be critical regime is unreachable with present resources, the numerical challenge is finally well posed.Comment: 42 pages, 19 figures. Minor changes and added figure (results unchanged

The potential for measuring ethnicity and health in a multicultural milieu - the case of type 2 diabetes in Australia

ObjectiveEthnicity influences health in many ways. For example, type 2&nbsp;diabetes (T2DM) is disproportionately prevalent among certain ethnic groups.&nbsp;Assessing ethnicity is difficult, and numerous proxy measures are used to&nbsp;capture its various components. Australian guidelines specify a set of&nbsp;variables for measuring ethnicity, and how such parameters should be&nbsp;categorised. Using T2DM data collections as an illustrative example, this&nbsp;study sought to examine how ethnicity is measured in Australian health&nbsp;databases and, by comparing current practice with Australia&rsquo;s existing&nbsp;benchmark recommendations, to identify potential areas for improvement of&nbsp;the health data landscape.DesignWe identified databases containing information from which ethnic&nbsp;group-specific estimates of T2DM burden may be gleaned. For each&nbsp;database, details regarding ethnicity variables were extracted, and compared&nbsp;with the Australian guidelines.&nbsp;ResultsData collection instruments for 32 relevant databases were reviewed.&nbsp;Birthplace was recorded in 27 databases (84%), but mode of birthplace&nbsp;assessment varied. Indigenous status was commonly recorded (78%, n=25), but&nbsp;only nine databases recorded other aspects of self-perceived race/ethnicity. Of&nbsp;28 survey/audit databases, 14 accommodated linguistic preferences other than&nbsp;English, and 11 either excluded non-English speakers or those for whom a&nbsp;translator was not available, or only offered questionnaires in English.ConclusionsConsiderable variation exists in the measurement of ethnicity in&nbsp;Australian health data- sets. While various markers of ethnicity provide&nbsp;complementary information about the ethnic profile within a data-set, nonuniform&nbsp;measurement renders comparison between data-sets difficult. A&nbsp;standardised approach is necessary, and identifying the ethnicity variables&nbsp;that are particularly relevant to the health sector is warranted. Including self identified&nbsp;ethnicity in Australia&rsquo;s set of recommended indicators and as a core&nbsp;component of the national census should be considered. Globalisation and&nbsp;increasing migration mean that these findings have implications internationally,&nbsp;including for multi-ethnic countries throughout North America and&nbsp;Europe.</div

Preventing diabetes through a lifestyle modification program that works

The Greater Green Triangle Diabetes Prevention Project was a national demonstrator program that was conducted in Hamilton, Horsham and Mount Gambier by the GGT UDRH in 2004 to 2006. The project was based on the Finnish Diabetes Prevention Study and the Good Ageing in Lahti Region Lifestyle Implementation Trial. It involved a series of group education sessions delivered to people at high risk of developing diabetes. As the positive effect of diabetes prevention programs is already well established, the aim of this study was to evaluate the feasibility of delivering a structured group-based lifestyle modification program in Australian primary care settings with modest resources. A follow-up investigation looked at whether gains achieved by the intervention were sustained longer term and whether telephone support would provide better outcomes

Occupational differences, cardiovascular risk factors and lifestyle habits in South Eastern rural Australia

BACKGROUND: In rural and remote Australia, cardiovascular mortality and morbidity rates are higher than metropolitan rates.This study analysed cardiovascular and other chronic disease risk factors and related health behaviours by occupational status, to determine whether agricultural workers have higher cardiovascular disease (CVD) risk than other rural workers. METHODS: Cross-sectional surveys in three rural regions of South Eastern Australia (2004-2006). A stratified random sample of 1001 men and women aged 25-74 from electoral rolls were categorised by occupation into agricultural workers (men = 214, women = 79), technicians (men = 123), managers (men = 148, women = 272) and 'home duties' (women = 165). Data were collected from self-administered questionnaire, physical measurements and laboratory tests. Cardiovascular disease (CVD) and coronary heart disease (CHD) risk were assessed by Framingham 5 years risk calculation. RESULTS: Amongst men, agricultural workers had higher occupational physical activity levels, healthier more traditional diet, lower alcohol consumption, lower fasting plasma glucose, the lowest proportion of daily smokers and lower age-adjusted 5 year CVD and CHD risk scores.Amongst women, managers were younger with higher HDL cholesterol, lower systolic blood pressure, less hypertension, lower waist circumference, less self-reported diabetes and better 5 year CVD and CHD risk scores.Agricultural workers did not have higher cardiovascular disease risk than other occupational groups. CONCLUSIONS: Previous studies have suggested that farmers have higher risks of cardiovascular disease but this is because the risk has been compared with non-rural populations. In this study, the comparison has been made with other rural occupations. Cardiovascular risk reduction programs are justified for all. Programs tailored only for agricultural workers are unwarranted