Rapidly reconfigurable optically induced photonic crystals in hot rubidium vapor

Through periodic index modulation, we create two different types of photonic structures in a heated rubidium vapor for controlled reflection, transmission and diffraction of light. The modulation is achieved through the use of the AC Stark effect resulting from a standing-wave control field. The periodic intensity structures create translationally invariant index profiles analogous to photonic crystals in spectral regions of steep dispersion. Experimental results are consistent with modeling.Comment: 6 pages, 6 figure

Mapping the impacts of farmed Scottish salmon from a Life Cycle perspective

Purpose  The European Union relies on seafood imports to supply growing demand that European production has failed to meet. Politically motivated media reports have denigrated competing imports in favour of local production. While life cycle assessment (LCA) measures global impact of value chains, it often fails to contextualise them. Using LCA, this article takes farmed Scottish Atlantic salmon as a case study of “local” production to identify and map the contributions to global environmental impact.  Methods  Data on the Scottish salmon value chain were collected by structured survey from a large international feed mill, six farms and a major processor. Secondary data were collected from available literature on feed ingredients and background data from EcoInvent2.2. A mid-point CML2001 approach was adopted focussing on global warming potential (GWP), acidification potential (AP), eutrophication potential, ozone depletion potential, photo-chemical oxidation potential, consumptive water use and land use. Results were displayed as contribution analyses of materials and processes and mapped geographically using area plots.  Results and discussion  Far from being a “locally” produced commodity, nearly 50% of the feed ingredients were sourced from South America and less than 25% originated in the UK. It was found that over 90% of the impact to farm-gate was embodied in feed, apart from eutrophication potential which was high at the farm from direct nitrogenous emissions into the marine environment. The majority of impacts do not occur in Scotland, particularly for land and water use, which occur at a more geographically significant level than GWP or AP, which are more global or regional impacts, respectively. High GWP emissions from vegetable-based ingredients were related to soil management and energy intensive processes such as wet milling to produce gluten from wheat and maize, sunflower and rapeseed oil processing.  Conclusions  The results show that in an age of globalised commodity trading, concerns around “local” production are often misleading. As consumers try to make more responsible purchase choices, they may be misled over the global impacts their choices are having. There are clearly trade-offs between different feed ingredients, especially regarding substitution of marine ingredients with those of vegetable origin. While marine ingredients perform comparatively well, they are highly limited, and biodiversity impacts of different ingredients are less clear and difficult to compare

Farmed salmon is now a staple in diets - but what they eat matters too

First paragraph: Salmon is not only tasty but is prized for being low fat and high in rich omega-3 oils. In recent times, salmon has been a staple of the national diet, so much so that wild salmon has given way to a huge global farmed industry, worth US$15.4 billion. Salmon are farmed in net pens suspended from floating collars in the sea. Like other types of farming, quality varies and the industry has sometimes come in for criticism over the health and welfare of fish.https://theconversation.com/farmed-salmon-is-now-a-staple-in-diets-but-what-they-eat-matters-too-5354

The impacts of integrated homestead pond-dike systems in relation to production, consumption and seasonality in central north Bangladesh

The roles of homestead ponds and surrounding dike production of vegetables on farms in peri-urban and rural communities in central north Bangladesh were assessed. A baseline survey sought to characterize actively managed (“active”) pond-dike systems, producing fish and vegetables, in terms of productivity and impact compared to less intensively integrated (“passive”) and control, no-pond households. A longitudinal survey was carried out over 12months to explore the relationship between seasonality and livelihood outcomes in relation to location and well-being status. Active homestead pond operators tended to have greater access to information and credit compared to passive and non-pond households; this was likely linked to their greater literacy and greater social connectedness. They enjoyed higher incomes through fish sales and consumed more fish than passive households, which was related to their higher production, in turn explained mainly by the use of more inputs. All active, 50% passive and 38% non-pond households were involved in vegetable cultivation; however, significantly more vegetables were produced by active households than others. The impacts of pond-dike production were more critical for food-vulnerable, rural households than peri-urban households prior to monsoon rice harvest; worse-off households suffered more prior to the “irrigated rice” harvest. Fish and vegetables raised on farm were most important during lower income months. The study supports the view that small homestead ponds can contribute to the wider food supply, and that such “quasi-peasant” forms of aquaculture contribute to reduced poverty and enhanced dietary diversity and food security in the broader population

Assumptions for a Market Share Theorem

Many marketing models use variants of the relationship: market share equals marketing effort divided by total marketing effort. Usually, share is defined within a customer group presumed to be reasonably homogeneous and overall share is obtained by weighting for the number in the group. Although the basic relationship can be assumed directly, certain insight is gained by deriving it from more fundamental assumptions as follows: For the given customer group, each competitive seller has a real-valued "attraction" with the following properties: (1) attraction is non-negative; (2) the attraction of a set of sellers is the sum of the attractions of the individual sellers; and (3) if the attractions of two sets of sellers are equal, the sellers have equal market shares in the customer groups. It is shown that, if the relation between share and attraction satisfies the above assumptions, is a continuous function, and is required to hold for arbitrary values of attraction and sets of sellers, then the relation is: Share equals attraction divided by total attraction. Insofar as various factors can be assembled into an attraction function that satisfies the assumptions of the theorem, the method for calculating share follows directly

It’s the way he tells them (and who is listening):men’s dominance is positively correlated with their preference for jokes told by dominant-sounding men

While much research has explored humorous exchange in relation to mate choice, recent perspectives have emphasized the importance of humor for monitoring interest within social partnerships more generally. Indeed, given that similarity is thought to be important in the maintenance of social partnerships, we may expect humor appreciation to vary according to the degree of similarity between humor producers and recipients. In the current study we report evidence for such variation that is specific to men’s judgments of other men’s humor. Here we manipulated voice pitch in a set of ‘one-liner’ jokes to create low-pitched and high-pitched versions of men and women telling jokes. A composite measure of men’s own dominance was positively correlated with their preference for jokes told by other men with lowered voice pitch (a vocal cue to dominance). A follow-up study demonstrated that self-reported dominance was positively related to men’s choice of low-pitch men as friends when judging humorous audio clips but not when judging neutral control audio clips, suggesting that humor may be important in mediating the effect of dominance on friendship choice. These studies indicate systematic variation in humor appreciation related to friendship choices which may function to promote cohesion within male partnerships based on status

Lean, green, mean, obscene…? What is efficiency? And is it sustainable? Animal production and consumption reconsidered

First paragraph: “Food systems need to become more efficient. We need to produce food in ways that use fewer resources and generate fewer negative environmental impacts. This drive towards efficiency is essential if we are to achieve more sustainable food systems.”  Such is the typical conclusion of numerous policy documents and industry statements, based on academic papers published in agricultural science and life cycle assessment journals.  It is a well-rehearsed observation that the food system today is undermining the environment upon which future food production depends. We know too that given current trends, our problems are set to grow, not just because our population is growing, meaning more mouths to feed, but also because our food demands are changing. As people on average become richer, they demand and can afford not just more food, but more of the foods that they like, notably those of animal origin. The rearing of animals for flesh, eggs and milk generates some 14.5% of total global GHG emissions, occupies 70% of agricultural land and is the main cause of the environmental problems such as biodiversity loss and water pollution.1,2 Moving from land to water, there are major concerns about the depletion of wild fish stocks and the negative effects of over fishing on aquatic ecosystems. Aquaculture production bridges and is linked to concerns in both the terrestrial and aquatic domains: it is a user of land based resources, but its production has been underpinned in recent years on wild fish stocks used as feed inputs.  While there is general agreement that action is needed to address the environmental problems caused by the food system, what such ‘action’ should be is the subject of substantial attention and debate within the policy, academic, business and NGO communities. One word that comes up time and again in discussions about the way forward is ‘efficiency.&rsquo

Aquaculture: a rapidly growing and significant source of sustainable food? Status, transitions and potential

The status and potential of aquaculture is considered as part of a broader food landscape of wild aquatic and terrestrial food sources. The rationale and resource base required for the development of aquaculture are considered in the context of broader societal development, cultural preferences and human needs. Attention is drawn to the uneven development and current importance of aquaculture globally as well as its considerable heterogeneity of form and function compared with established terrestrial livestock production. The recent drivers of growth in demand and production are examined and the persistent linkages between exploitation of wild stocks, full life cycle culture and the various intermediate forms explored. An emergent trend for sourcing aquaculture feeds from alternatives to marine ingredients is described and the implications for the sector with rapidly growing feed needs discussed. The rise of non-conventional and innovative feed ingredients, often shared with terrestrial livestock, are considered, including aquaculture itself becoming a major source of marine ingredients. The implications for the continued expected growth of aquaculture are set in the context of sustainable intensification, with the challenges that conventional intensification and emergent integration within, and between, value chains explored. The review concludes with a consideration of the implications for dependent livelihoods and projections for various futures based on limited resources but growing demand

Let them eat carp: Fish farms are helping to fight hunger

First paragraph: Over the past three decades, the global aquaculture industry has risen from obscurity to become a critical source of food for millions of people. In 1990, only 13 percent of world seafood consumption was farmed; by 2014, aquaculture was providing more than half of the fish consumed directly by human beings.  The boom has made farmed fish like shrimp, tilapia and pangasius catfish – imported from countries such as Thailand, China and Vietnam – an increasingly common sight in European and North American supermarkets. As a result, much research on aquaculture has emphasized production for export.  This focus has led scholars to question whether aquaculture contributes to the food security of poorer people in producing countries. Many have concluded it does not. Meanwhile, the industry’s advocates often emphasize the potential for small-scale farms, mainly growing fish for home consumption, to feed the poor. Farms of this kind are sometimes claimed to account for 70 to 80 percent of global aquaculture production