The employment benefits of organic farming

Organic farming in the UK provides a range of economic and social benefi ts. In particular, it provides 32% more jobs per farm than equivalent non-organic farms. These new findings are based on the fi rst national survey of employment on UK organic farms, carried out by the University of Essex for the Soil Association. Organic farming is helping to reverse the decline in the UK’s agricultural workforce, which has fallen by 80% in the last 50 years. In contrast to the ageing overall farming population, organic farmers are, on average, seven years younger than their non-organic counterparts. Organic farmers are also three times more likely to be engaged in business innovations activities, such as direct marketing and on-farm processing. If all UK farmers adopted organic farming, it would produce an additional 93,000 on-farm jobs. These findings have significant implications for developing countries where a skilled agricultural workforce is vital to safeguard livelihoods and ensure global food security

Evolutionary Stability of Ecological Hierarchy

A self-similar hierarchical solution that is both dynamically and evolutionarily stable is found to the multi dimensional Lotka-Volterra equation with a single chain of prey-predator relations. This gives a simple and natural explanation to the key features of hierarchical ecosystems, such as its ubiquity, pyramidal population distribution, and higher aggressiveness among higher trophic levels. pacs{87.23.Kg, 89.75.Da, 05.45.-a} keywords{Lotka-Volterra equation, Trophic pyramid, Self-similarity}Comment: 4 Pages RevTeX4, 1 Fig, 1 Table, shortened by publishers reques

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

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

Prisoner's Dilemma cellular automata revisited: evolution of cooperation under environmental pressure

We propose an extension of the evolutionary Prisoner's Dilemma cellular automata, introduced by Nowak and May \cite{nm92}, in which the pressure of the environment is taken into account. This is implemented by requiring that individuals need to collect a minimum score $U_{min}$, representing indispensable resources (nutrients, energy, money, etc.) to prosper in this environment. So the agents, instead of evolving just by adopting the behaviour of the most successful neighbour (who got $U^{msn}$), also take into account if $U^{msn}$ is above or below the threshold $U_{min}$. If $U^{msn}<U_{min}$ an individual has a probability of adopting the opposite behaviour from the one used by its most successful neighbour. This modification allows the evolution of cooperation for payoffs for which defection was the rule (as it happens, for example, when the sucker's payoff is much worse than the punishment for mutual defection). We also analyse a more sophisticated version of this model in which the selective rule is supplemented with a "win-stay, lose-shift" criterion. The cluster structure is analyzed and, for this more complex version we found power-law scaling for a restricted region in the parameter space.Comment: 15 pages, 8 figures; added figures and revised tex

The normalization of sibling violence: Does gender and personal experience of violence influence perceptions of physical assault against siblings?

Despite its pervasive and detrimental nature, sibling violence (SV) remains marginalized as a harmless and inconsequential form of familial aggression. The present study investigates the extent to which perceptions of SV differ from those of other types of interpersonal violence. A total of 605 respondents (197 males, 408 females) read one of four hypothetical physical assault scenarios that varied according to perpetrator–victim relationship type (i.e., sibling vs. dating partner vs. peer vs. stranger) before completing a series of 24 attribution items. Respondents also reported on their own experiences of interpersonal violence during childhood. Exploratory factor analysis reduced 23 attribution items to three internally reliable factors reflecting perceived assault severity, victim culpability, and victim resistance ratings. A 4 × 2 MANCOVA—controlling for respondent age—revealed several significant effects. Overall, males deemed the assault less severe and the victim more culpable than did females. In addition, the sibling assault was deemed less severe compared to assault on either a dating partner or a stranger, with the victim of SV rated just as culpable as the victim of dating, peer, or stranger-perpetrated violence. Finally, respondents with more (frequent) experiences of childhood SV victimization perceived the hypothetical SV assault as being less severe, and victim more culpable, than respondents with no SV victimization. Results are discussed in the context of SV normalization. Methodological limitations and applications for current findings are also outlined

A Meta-analytic review of the prevalence of neuropathic pain in the general population of the global south compared to the global north

Background It is suspected that the prevalence of Neuropathic pain (NeP) is higher in the countries normally categorized as belonging to the global South, i.e. developing countries, because of the high prevalence of NeP generating diseases including HIV, diabetes mellitus and cancer. However, few articles have estimated the prevalence of NeP in these limited resource countries. By contrast, the prevalence of NeP worldwide has been evaluated in two systematic reviews to range between 3.3% in Austria to 8.2% in the UK (Smith and Torrance, 2012, Hecke et al., 2014) with an outlier of prevalence at 17% in Canada. Aims The aim of this systematic review was to screen the literature for the prevalence of NeP in the general population of the global South and to compare this prevalence with the prevalence in the global North using a meta-analytic approach. Methods Pubmed; Siencedirect; EMBASE; AMED and PsycINFO databases were searched on July 2016 to capture peer reviewed articles that contain data on NeP prevalence either in adult general populations or among chronic pain patients. Two reviewers applied the inclusion criteria and extracted information from all eligible studies including study period, country, study design, sample size, tools to diagnose NeP, outcome and overall prevalence and judged the outcome for each study by scrutinising the methods and result section. Guidelines for reporting Meta-Analysis of Observational Studies in Epidemiology (MOOSE) (Stroup, 2000) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) (Moher, 2009) were followed. Random effects modelling was applied on extracted data to produce the overall prevalence in the two study areas. Effect size and confidence intervals of overall prevalences was calculated by producing Forest plots in the Comprehensive Meta-analysis software. Risk of publication bias and heterogeneity between studies were also estimated. Results Out of the 624 studies identified in the search 14 studies were finally selected (total sample size of 78421 patients, 8137 from developing countries (global south) and 70284 from developed countries (global north). The average quality score of all studies was 6.7 out of a maximum of 8. There was a high level of heterogeneity between the studies (I2>90) possibly because of differences in the target populations, sample sizes, study design and data collection methods. However, there was no publication bias as the Egger’s test value was not significant (p=0.053). The prevalence of NeP worldwide was 4.8 % (95%CI, 4.7%-5.0%). Only four studies were conducted in the global South; 2 in Libya, 1 in Morocco and 1 in Brazil. The prevalence of NeP in the global South was 8.3% (7.7%-9.0%). The overall prevalence in the global North was 4.9% (4.7%-6.0%). Conclusion There were few studies on the prevalence of NeP in the global South suggesting that there is less awareness of the significance of NeP in the developing countries. Differences exist between the studies in each region in the estimate of the prevalence of NeP and this is mainly because of differences in data collection methods. Clinical examination tends to produce more variable estimates than telephone, postal and internet based questionnaires using NeP screening tools such as DN4 and S-LANSS. This meta-analysis tentatively suggests that the prevalence of NeP is significantly higher in the global South compared to global North

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

Group selection models in prebiotic evolution

The evolution of enzyme production is studied analytically using ideas of the group selection theory for the evolution of altruistic behavior. In particular, we argue that the mathematical formulation of Wilson's structured deme model ({\it The Evolution of Populations and Communities}, Benjamin/Cumings, Menlo Park, 1980) is a mean-field approach in which the actual environment that a particular individual experiences is replaced by an {\it average} environment. That formalism is further developed so as to avoid the mean-field approximation and then applied to the problem of enzyme production in the prebiotic context, where the enzyme producer molecules play the altruists role while the molecules that benefit from the catalyst without paying its production cost play the non-altruists role. The effects of synergism (i.e., division of labor) as well as of mutations are also considered and the results of the equilibrium analysis are summarized in phase diagrams showing the regions of the space of parameters where the altruistic, non-altruistic and the coexistence regimes are stable. In general, those regions are delimitated by discontinuous transition lines which end at critical points.Comment: 22 pages, 10 figure