Competition and cooperation in one-dimensional stepping stone models

Cooperative mutualism is a major force driving evolution and sustaining ecosystems. Although the importance of spatial degrees of freedom and number fluctuations is well-known, their effects on mutualism are not fully understood. With range expansions of microbes in mind, we show that, even when mutualism confers a distinct selective advantage, it persists only in populations with high density and frequent migrations. When these parameters are reduced, mutualism is generically lost via a directed percolation process, with a phase diagram strongly influenced by an exceptional DP2 transition.Comment: 8 pages, 4 figure

Phase Diagrams of Quasispecies Theory with Recombination and Horizontal Gene Transfer

We consider how transfer of genetic information between individuals influences the phase diagram and mean fitness of both the Eigen and the parallel, or Crow-Kimura, models of evolution. In the absence of genetic transfer, these physical models of evolution consider the replication and point mutation of the genomes of independent individuals in a large population. A phase transition occurs, such that below a critical mutation rate an identifiable quasispecies forms. We generalize these models of quasispecies evolution to include horizontal gene transfer. We show how transfer of genetic information changes the phase diagram and mean fitness and introduces metastability in quasispecies theory, via an analytic field theoretic mapping.Comment: 5 pages, 1 figure, to appear in Physics Review Letter

The Nutritional Content of Main Course Ready-meals Aimed at Children Aged 12 Months to 3 Years

Background: Rapid changes to dietary and lifestyle patterns have transformed the home and food environment with an increased trend towards convenience in home food preparation and ready-meal availability [1]. Despite the widespread use of convenience foods, there is a lack of research into the nutritional quality of convenience foods for young children. This study examined the nutritional content of ready-meals for children aged 12 months to 3 years. The objectives of this study were to (i) investigate the nutritional quality of ready-meals, on sale in the UK market for children aged 12 months to 3 years, comparing their nutrition labelling information to dietary standards, (ii) identify the nutrition claims on the packaging of ready-meals for this age group and (iii) determine whether the nutrition claims identified met European Union legislation. Methods: A sample of main course ready-meals (n=38) marketed to children aged 12 months to 3 years from five brands, available in the UK was assessed. One ready-meal represents only a proportion of energy and nutrients consumed per day, therefore dietary standards were obtained taking 30% of age-appropriate dietary reference values (DRVs). The energy, protein and sodium content of these ready-meals were compared to the calculated dietary standards using one sample t-tests. Descriptive analysis was performed on all nutritional information (energy, carbohydrate, sugars, protein, fat, saturated fat, fibre, sodium and iron) collected. Nutrition claims were validated against legislative requirements [2,3,4]. Results: All ready-meals examined were significantly lower in energy (p=0.000) and higher in protein (p=0.000) compared to the dietary standards. Sodium was significantly higher than the dietary standard in three brands; brand 1 (p=0.000), 3 (p=0.004) and 5 (p=0.03), with brand 5 containing only 65mg less than the DRV (500mg) for total daily allowance. Four of the nutrition claims made across the brands were assessed - “no added salt”, “no added sugar”, “low salt” and “source of iron”. Only brand 1 and 5 did not meet legislation for “no added salt” as the ready-meals contained more than the amount of sodium per 100g permitted. All other nutrition claims conformed to legislative requirements; however the majority of ready-meals from brand 1 did contain ingredients with added salt and/or sugar e.g. mustard or sun-dried tomato, despite claims of “no added salt/sugar” and this could misinform consumers. Discussion: The ready-meals investigated did not meet calculated dietary standards and although the majority of nutrition claims displayed on the packaging did meet legislation, some claims did not and there were claims that could mislead consumers. There is paucity in research into the nutritional quality of convenience foods for young children and therefore comparisons between this study and other work cannot be drawn. Furthermore, since comprehensive dietary standards are unavailable for this age group, it is difficult to fully assess the nutritional adequacy of these ready-meals. Conclusion: The development of nutritional standards and transparent nutrition claim legislation would enable practitioners to fully assess the adequacy of children’s diets and enable consumers to make healthier food choices. Keywords : Children’s ready-meals; convenience foods; nutrition labelling

Altruistic Contents of Quantum Prisoner's Dilemma

We examine the classical contents of quantum games. It is shown that a quantum strategy can be interpreted as a classical strategies with effective density-dependent game matrices composed of transposed matrix elements. In particular, successful quantum strategies in dilemma games are interpreted in terms of a symmetrized game matrix that corresponds to an altruistic game plan.Comment: Revised according to publisher's request: 4 pgs, 2 fgs, ReVTeX4. For more info, go to http://www.mech.kochi-tech.ac.jp/cheon

Potential application of liquid dye penetrants for serial number restoration on firearms

© 2018, © 2018 Australian Academy of Forensic Sciences. Chemical reagents for serial number restoration are designed to exploit the plastic deformation zone below the obliterated serial number. Most techniques in operational use are variants of Fry’s Reagent. This technique uses toxic, corrosive chemicals and requires a skilful operator in the laboratory. Fry’s Reagent can also be destructive of the firearm due to rusting. In an attempt to find a non-toxic, non-destructive alternative to Fry’s Reagent, this project tested the use of liquid dye penetrants (LDPs), a non-destructive examination technique to detect cracks and imperfections used in the welding industry, for the restoration of obliterated serial numbers. Steel plates bearing an obliterated serial number with a range of obliteration depths were subjected to LDP treatment under various treatment conditions. The results using LDPs were negative for all obliteration depths and all test conditions attempted. Some of the serial numbers were subsequently restored successfully with Fry’s reagent, proving that the plastic deformation zone was present on the steel plates below the obliteration. Further work to develop a non-toxic, non-destructive serial number restoration process will be undertaken

A strengths-based consultancy approach in elite sport : exploring super strengths.

There is a lack of literature documenting strengths-based approaches in sport psychology. This study explored how a super-strengths approach has been implemented by sport psychologists (n = 7) and coaches (n = 8), with UK elite athletes. Findings were categorized into 3 general dimensions: defining super-strengths, identification methods, and phases of development. Super-strengths were defined as a strategy for performance, utilizing a potential world’s-best resource to gain a competitive edge. Identification methods were subjective (e.g., asking/observing athletes) and objective (e.g., performance analysis). Participants emphasized 3 development phases: preparation, adaptation and monitoring. Findings offer considerations for implementing a strengths-based approach and future research

Origin of complexity in multicellular organisms

Through extensive studies of dynamical system modeling cellular growth and reproduction, we find evidence that complexity arises in multicellular organisms naturally through evolution. Without any elaborate control mechanism, these systems can exhibit complex pattern formation with spontaneous cell differentiation. Such systems employ a `cooperative' use of resources and maintain a larger growth speed than simple cell systems, which exist in a homogeneous state and behave 'selfishly'. The relevance of the diversity of chemicals and reaction dynamics to the growth of a multicellular organism is demonstrated. Chaotic biochemical dynamics are found to provide the multi-potency of stem cells.Comment: 6 pages, 2 figures, Physical Review Letters, 84, 6130, (2000

Equation of state in 2+1 flavor QCD with improved Wilson quarks by the fixed scale approach

We study the equation of state in 2+1 flavor QCD with nonperturbatively improved Wilson quarks coupled with the RG-improved Iwasaki glue. We apply the $T$-integration method to nonperturbatively calculate the equation of state by the fixed-scale approach. With the fixed-scale approach, we can purely vary the temperature on a line of constant physics without changing the system size and renormalization constants. Unlike the conventional fixed-$N_t$ approach, it is easy to keep scaling violations small at low temperature in the fixed scale approach. We study 2+1 flavor QCD at light quark mass corresponding to $m_\pi/m_\rho \simeq 0.63$, while the strange quark mass is chosen around the physical point. Although the light quark masses are heavier than the physical values yet, our equation of state is roughly consistent with recent results with highly improved staggered quarks at large $N_t$.Comment: 14 pages, 12 figures, v2: Table I and Figure 3 are corrected, reference updated. Main discussions and conclusions are unchanged, v3: version to appear in PRD, v4: reference adde

Perceptions of Engaging with a Super-Strengths Approach in Elite Sport

Strengths-based approaches (underpinned by positive psychology) are scarcely documented in sport. This study explored perceptions of a strengths-based approach (termed super-strengths) on psychological characteristics and performance in elite sport. Semi-structured interviews were conducted with athletes (N=12) who had previous experience of working with a sport psychology practitioner on super-strengths. Thematic analysis of the data (Braun & Clarke, 2006) indicated that super-strengths had a positive influence on athletes’ mind-set, confidence (e.g., self-belief), clarity of purpose (e.g., goal direction), drive, coping ability, and performance. Findings highlight the potential benefits of adopting strengths-based approaches in sport, and recommendations for future research are provided. Key words: positive, performance psychology, confidence, elite sport

Information sharing promotes prosocial behaviour

More often than not, bad decisions are bad regardless of where and when they are made. Information sharing might thus be utilized to mitigate them. Here we show that sharing information about strategy choice between players residing on two different networks reinforces the evolution of cooperation. In evolutionary games, the strategy reflects the action of each individual that warrants the highest utility in a competitive setting. We therefore assume that identical strategies on the two networks reinforce themselves by lessening their propensity to change. Besides network reciprocity working in favour of cooperation on each individual network, we observe the spontaneous emergence of correlated behaviour between the two networks, which further deters defection. If information is shared not just between individuals but also between groups, the positive effect is even stronger, and this despite the fact that information sharing is implemented without any assumptions with regard to content