Expected Sensitivity to Galactic/Solar Axions and Bosonic Super-WIMPs based on the Axio-electric Effect in Liquid Xenon Dark Matter Detectors

We present systematic case studies to investigate the sensitivity of axion searches by liquid xenon detectors, using the axio-electric effect (analogue of the photoelectric effect) on xenon atoms. Liquid xenon is widely considered to be one of the best target media for detection of WIMPs (Weakly Interacting Massive Particles which may form the galactic dark matter) using nuclear recoils. Since these detectors also provide an extremely low radioactivity environment for electron recoils, very weakly-interacting low-mass particles (< 100 keV/c^2), such as the hypothetical axion, could be detected as well - in this case using the axio-electric effect. Future ton-scale liquid Xe detectors will be limited in sensitivity only by irreducible neutrino background (pp-chain solar neutrino and the double beta decay of 136Xe) in the mass range between 1 and 100 keV/c^2. Assuming one ton-year of exposure, galactic axions (as non-relativistic dark matter) could be detected if the axio-electric coupling g_Ae is greater than 10^-14 at 1 keV/c^2 (or $10^-13 at 100 keV/c^2). Below a few keV/c^2, and independent of the mass, a solar axion search would be sensitive to a coupling g_Ae ~ 10^-12. This limit will set a stringent upper bound on axion mass for the DFSV and KSVZ models for the mass ranges m_A < 0.1 eV/c^2 and < 10 eV/c^2, respectively. Vector-boson dark matter could also be detected for a coupling constant alpha'/alpha > 10^-33 (for mass 1 keV/c^2) or > 10^-27 (for mass 100 keV/c^2).Comment: 17 pages, 10 figure

Thin film evolution equations from (evaporating) dewetting liquid layers to epitaxial growth

In the present contribution we review basic mathematical results for three physical systems involving self-organising solid or liquid films at solid surfaces. The films may undergo a structuring process by dewetting, evaporation/condensation or epitaxial growth, respectively. We highlight similarities and differences of the three systems based on the observation that in certain limits all of them may be described using models of similar form, i.e., time evolution equations for the film thickness profile. Those equations represent gradient dynamics characterized by mobility functions and an underlying energy functional. Two basic steps of mathematical analysis are used to compare the different system. First, we discuss the linear stability of homogeneous steady states, i.e., flat films; and second the systematics of non-trivial steady states, i.e., drop/hole states for dewetting films and quantum dot states in epitaxial growth, respectively. Our aim is to illustrate that the underlying solution structure might be very complex as in the case of epitaxial growth but can be better understood when comparing to the much simpler results for the dewetting liquid film. We furthermore show that the numerical continuation techniques employed can shed some light on this structure in a more convenient way than time-stepping methods. Finally we discuss that the usage of the employed general formulation does not only relate seemingly not related physical systems mathematically, but does as well allow to discuss model extensions in a more unified way

Opportunities for mainstreaming biodiversity for food and nutrition into institutional food procurement programs in Brazil

Brazil has a well-established political and regulatory framework aimed at promoting food and nutritional security. This framework represents an innovative and ethical social contract aimed at achieving social inclusion, sustainable livelihoods and citizenship. It includes the Food Acquisition Program (PAA) and the National School Meals Program (PNAE), institutional food procurement programs which provide equitable support to family farming by acquiring their products at a fair price and directing them to public schools, public programs and social organisations. PNAE and PAA have been identified by the GEF-funded Biodiversity for Food and Nutrition Project (BFN) as entry-points for potentially improving nutrition and livelihoods with links to native biodiversity. At least 30% of the food purchased with federal funds through PNAE must be bought directly from family farmers. Both initiatives include ethical standards and incentives of up to 30% in the price for organic or agroecological produce, prioritising purchases from quilombolas and indigenous communities, while also supporting family agriculture organisations to rescue, produce, store, and distribute seeds of local or traditional varieties. This creates new opportunities for the use of resources from Brazilian ecosystems, promoting institutional markets for biodiversity products while providing incentives for the management and sustainable use of agricultural biodiversity. However, assessments reveal that the proportion of food products from native biodiversity purchased overall by PNAE and PAA are low, which also reflects the current status of Brazilian agriculture, based mostly on exotic species. In order to better mainstream biodiversity into PNAE and PAA, the BFN Project in Brazil is working to increase awareness on the importance and nutritional value of native biodiversity species. Advocacy workshops, capacity building, as well as strategic alliances and partnerships with policy makers and other stakeholders are an important element of this, as are contributions to policy instruments that impact both programs. BFN also engages with Federal Universities, which are also collaborating centres for the implementation of PNAE, in research partnerships and activities to conduct analysis on the nutritional composition of 70 prioritised native fruit species and work with traditional communities to assess the knowledge and use of biodiversity foods

Diversifying institutional food procurement – opportunities and barriers for integrating biodiversity for food and nutrition in Brazil

The Brazilian Food Procurement Program (PAA) and the National School Feeding Program (PNAE) were identified by the GEF-funded Biodiversity for Food and Nutrition Project (BFN)1 as policy instruments with the greatest potential for diversifying institutional food procurement and improving di- ets while supporting family farming. This paper discusses the opportunities identified for mainstream- ing biodiversity through PAA and PNAE, targeted activities undertaken as well as two case studies. The first case study presents findings linked to the implementation of the PNAE in quilombola communi- ties in Goiás, while the second describes results of the inclusion of Juçara fruits (Euterpe edulis Mart.) in school meals in São Paulo. The paper concludes by highlighting some of the key barriers to better biodiversity mainstreaming and institutional food procurement together with some recommendations