Bath induced coherence and the secular approximation

Finding efficient descriptions of how an environment affects a collection of discrete quantum systems would lead to new insights into many areas of modern physics. Markovian, or time-local, methods work well for individual systems, but for groups a question arises: does system-bath or inter-system coupling dominate the dissipative dynamics? The answer has profound consequences for the long-time quantum correlations within the system. We consider two bosonic modes coupled to a bath. By comparing an exact solution to different Markovian master equations, we find that a smooth crossover of the equations-of-motion between dominant inter-system and system-bath coupling exists - but requires a non-secular master equation. We predict a singular behaviour of the dynamics, and show that the ultimate failure of non-secular equations of motion is essentially a failure of the Markov approximation. Our findings justify the use of time-local theories throughout the crossover between system-bath dominated and inter-system-coupling dominated dynamics.PostprintPeer reviewe

Problems Associated with Making Mechanical Measurements on Water–Ice at Quasistatic and Dynamic Strain Rates

Abstract: Space penetrators are a potential method of inserting instrumentation onto ice-covered bodies in the solar system. Part of a study to see whether this is feasible involves numerically simulating impact of the penetrator into ice at impact velocities of a few 100 m/s. In order to do this accurately, it is necessary to have a constitutive model for water ice that is valid at the strain rates and temperatures relevant to impact in the Outer Solar System. This paper reports certain issues and difficulties that arose during a study to obtain this data

Development Discourse and Practice: Alternatives and New Directions from Postcolonial Perspectives

Development and aid programs, such as those aimed at promoting economic growth and prosperity in ‘Third World’ nations and transition economies, often arise out of Western and neo-liberal policy ideologies and practices. These programs may, in some cases, provide useful guidelines for restructuring institutional structures and governance mechanisms in nations that have long struggled with poverty, economic instability, health crises, and social and political turmoil. However, a growing number of critical voices are raising concerns over the guiding assumptions and inclusiveness of these policies and programs in their aims to promote economic development and social well-being in non-Western nations. We join these critical perspectives by way of postcolonial frameworks to highlight some of the problematic assumptions and oversights of development programs, while offering new alternatives and directions. By doing so, we contribute to organizational theorizing in a global context, as postcolonial insights provide much needed engagement with international aid policies and programs, as well as development organizations and institutions. To accomplish this, we offer a historical perspective on development, present a critique of the policies and practices guiding many aid programs, and conclude with suggestions emanating from postcoloniality

The production and reproduction of inequality in the UK in times of austerity

Inequality appears to be back on the intellectual and political agenda. This paper provides a commentary on this renewed interest, drawing on an empirical discussion of inequality in the UK. The paper argues that inequality should be seen as produced in the inherently unequal social relations of production, drawing attention to the role of social struggle in shaping dynamics of inequality. However, inequality is not just produced in dynamic class struggle in the formal economy, but also through the social reproduction of labour power on a day-to-day and inter-generational basis. As such, inequalities of household resources at any point in time may be reproductive of greater future inequality. It is argued that inequality has risen in the UK over recent decades because of changes in the social relations of production in the formal economy and social reproduction in the domestic sector, both of which have witnessed significant state interventions that have increased structural inequalities. It is argued that, absent of significant change, the underpinning structural dynamics in the UK will lead to further increases in inequality over the short and longer-term. Given this, we might expect to see an already emergent ‘New Politics of Inequality’ intensifying in the coming decades.n/

Protecting the environment through insect farming as a means to produce protein for use as livestock, poultry, and aquaculture feed

Securing protein for the approximate 10 billion humans expected to inhabit our planet by 2050 is a major priority for the global community. Evidence has accrued over the past 30 years that strongly supports and justifies the sustainable use of insects as a means to produce protein products as feed for pets, livestock, poultry, and aquacultured species. Researchers and entrepreneurs affiliated with universities and industries, respectively, from 18 nations distributed across North and South America, Europe, Asia, Africa and Australia contributed to the development of this article, which is an indication of the global interest on this topic. A brief overview of insects as feed for the aquaculture industry along with a review of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), as a model for such systems is provided

Dissolved organic carbon transformations and microbial community response to variations in recharge waters in a shallow carbonate aquifer

© 2016, The Author(s). In carbonate aquifers, dissolved organic carbon from the surface drives heterotrophic metabolism, generating CO2 in the subsurface. Although this has been a proposed mechanism for enhanced dissolution at the water table, respiration rates and their controlling factors have not been widely evaluated. This study investigates the composition and concentration of dissolved organic carbon (DOC) reaching the water table from different recharge pathways on a subtropical carbonate island using a combination of DOC concentration measurements, fluorescence and absorption characterisation. In addition, direct measurements of the microbial response to the differing water types were made. Interactions of rainfall with the vegetation, via throughfall and stemflow, increase the concentration of DOC. The highest DOC concentrations are associated with stemflow, overland recharge and dissolution hole waters which interact with bark lignin and exhibit strong terrestrial-derived characteristics. The groundwater samples exhibit the lowest concentrations of DOC and are comprised of refractory humic-like organic matter. The heterotrophic response seems to be controlled by the concentration of DOC in the sample. The terrestrially sourced humic-like matter in the stemflow and dissolution hole samples was highly labile, thus increasing the amount of biologically produced CO2 to drive dissolution. Based on the calculated respiration rates, microbial activity could enhance carbonate dissolution, increasing porosity generation by a maximum of 1%kyr−1 at the top of the freshwater lens

Bootstrapping the energy flow in the beginning of life.

This paper suggests that the energy flow on which all living structures depend only started up slowly, the low-energy, initial phase starting up a second, slightly more energetic phase, and so on. In this way, the build up of the energy flow follows a bootstrapping process similar to that found in the development of computers, the first generation making possible the calculations necessary for constructing the second one, etc. In the biogenetic upstart of an energy flow, non-metals in the lower periods of the Periodic Table of Elements would have constituted the most primitive systems, their operation being enhanced and later supplanted by elements in the higher periods that demand more energy. This bootstrapping process would put the development of the metabolisms based on the second period elements carbon, nitrogen and oxygen at the end of the evolutionary process rather than at, or even before, the biogenetic even