On the perturbative corrections around D-string instantons

We study ${\cal F}^4$-threshold corrections in an eight dimensional S-dual pair of string theories, as a prototype of dual string vacua with sixteen supercharges. We show that the orbifold CFT description of D-string instantons gives rise to a perturbative expansion similar to the one appearing on the fundamental string side. By an explicit calculation, using the Nambu-Goto action in the static gauge, we show that the first subleading term agrees precisely on the two sides. We then give a general argument to show that the agreement extends to all orders.Comment: 12 page

AdS/CFT correspondence and D1/D5 systems in theories with 16 supercharges

We discuss spectra of $AdS_3$ supergravities, arising in the near horizon geometry of D1/D5 systems in orbifolds/orientifolds of type IIB theory with 16 supercharges. These include models studied in a recent paper (hep-th/0012118), where the group action involves also a shift along a transversal circle, as well as IIB/$\Omega I_4$, which is dual to IIB on $K3$. After appropriate assignements of the orbifold group eigenvalues and degrees to the supergravity single particle spectrum, we compute the supergravity elliptic genus and find agreement, in the expected regime of validity, with the elliptic genus obtained using U-duality map from (4,4) CFTs of U-dual backgrounds. Since this U-duality involves the exchange of KK momentum $P$ and D1 charge $N$, it allows us to test the (4,4) CFTs in the $P < N/4$ and $N < P/4$ regimes by two different supergravity duals.Comment: 28 pages, no figure

Combinations of nisin with salt (NaCl) to control Listeria monocytogenes on sheep natural sausage casings stored at 6°C

This study evaluated the effect of combinations of nisin with salt (NaCl) to control Listeria monocytogenes on sheep natural sausage casings. Casings were inoculated with 3.0 x 105 cfu/g final inocula of L. monocytogenes, stored at 6&#176;C in different solutions of nisin at 0, 100, 150 and 200 &#236;g/g.Each combined with salt at 0, 4, 7 and 12% (w/v). Samples were taken at day 0, 10, 20, 35, 60 and 90 post-inoculation and the number of bacteria present was determined. The bactericidal effect of nisin against L. monocytogenes cells was evident where nisin was applied in combination with salts. In all treatments, nisin/salt mixtures induced a bacterial growth inhibitory effect greater than salt alone. These results indicate that nisin and salt synergistically and significantly inhibit the growth of L.monoctogenes in sheep natural casings. The use of nisin combined with salt as antibacterial agent will be appropriate for applications on natural sausage casing industries as natural preservatives to control foodborne pathogens. They can be used as growth inhibitors of L. monocytogenes, an important foodborne pathogens and spoiling bacterium. The main reason for their appropriateness is their natural origin, which consumers find comforting. These beneficial characteristics could increase casings safety and shelf life

Governance analysis of a community managed small-scale crab fishery in Madagascar: Novel use of an empirical framework

The Marine Protected Area Governance (MPAG) framework was developed to offer a structured, empirical approach for analysing governance and has been applied to marine protected areas (MPAs) around the world. This study sees the novel application of the MPAG framework to a small-scale mangrove crab fishery in northwest Madagascar. The country typifies developing country environmental governance challenges, due to its poverty, political instability and lack of state capacity, with bottom-up approaches often identified as a potential solution. In this context, small-scale fisheries (SSF) play a vital role in food security and poverty alleviation but are vulnerable to over-exploitation. The case study examines community-based management, including the role of three nascent fishing association managing portions of the fishery, within a mangrove ecosystem. Despite issues with underrepresentation of fishers in local resource management organizations that have partial responsibility for the mangrove habitats, some management measures and incentives have been applied, including the replantation of mangroves and fishery-wide gear restrictions. However, the analysis highlights market forces and migration are drivers with negative synergistic effects that cannot be controlled by bottom-up management. Incentives identified as needed or in need or strengthening require the support of external actors, the state, industry and or NGO(s). Thus, governance approaches should seek integration and move away from polarised solutions (top-down vs- bottom-up). As shown by other MPAG case studies, effective governance is dependent on achieving 'resilience through diversity', in terms of the diversity of both the actors and the incentives they are able to collectively employ

The Fuzzy Sphere: From The Uncertainty Relation To The Stereographic Projection

On the fuzzy sphere, no state saturates simultaneously all the Heisenberg uncertainties. We propose a weaker uncertainty for which this holds. The family of states so obtained is physically motivated because it encodes information about positions in this fuzzy context. In particular, these states realize in a natural way a deformation of the stereographic projection. Surprisingly, in the large $j$ limit, they reproduce some properties of the ordinary coherent states on the non commutative plane.Comment: 18 pages, Latex. Minor changes in notations. Version to appear in JHE

On zero-point energy, stability and Hagedorn behavior of Type IIB strings on pp-waves

Type IIB strings on many pp-wave backgrounds, supported either by 5-form or 3-form fluxes, have negative light-cone zero-point energy. This raises the question of their stability and poses possible problems in the definition of their thermodynamic properties. After having pointed out the correct way of calculating the zero-point energy, an issue not fully discussed in literature, we show that these Type IIB strings are classically stable and have well defined thermal properties, exhibiting a Hagedorn behavior.Comment: Latex, 13 pages. v2: regularization/renormalization prescription clarified, refs. adde

Thermodynamic behavior of IIA string theory on a pp-wave

We obtain the thermal one loop free energy and the Hagedorn temperature of IIA superstring theory on the pp-wave geometry which comes from the circle compactification of the maximally supersymmetric eleven dimensional one. We use both operator and path integral methods and find the complete agreement between them in the free energy expression. In particular, the free energy in the $\mu \to \infty$ limit is shown to be identical with that of IIB string theory on maximally supersymmetric pp-wave, which indicates the universal thermal behavior of strings in the large class of pp-wave backgrounds. We show that the zero point energy and the modular properties of the free energy are naturally incorporated into the path integral formalism.Comment: 25 pages, Latex, JHEP style, v4: revised for clarity without change in main contents, version to appear in JHE

Climate Change Impacts Can Be Differentially Perceived Across Time Scales: A Study Among the Tuareg of the Algerian Sahara

Unidad de excelencia María de Maeztu CEX2019-000940-MAs an Indigenous community of Algeria and the broader Sahel, the Tuareg hold unique ecological knowledge, which might contribute to broader models of place-based climate change impacts. Between January and April 2019, we carried out semi-structured interviews (N = 23) and focus group discussions (N = 3) in five villages of the province of Illizi, Algeria, to document the local Tuareg community's timeline and ecological calendar, both of which are instruments used to understand place-based reports of climate change impacts. The livelihoods of the Tuareg of Illizi are finely tuned to climate variability as reflected in changes reported in the cadence of events in their ecological calendar (marked by cyclical climatic and religious events). Participants reported rain and temperature irregularities and severe drought events, which have impacted their pastoral and semi-pastoral livelihoods. These reports are aligned with scientifically measured climate observations and predictions. Paradoxically, although participants recall with detail the climatic disasters that happened in the region over the last century, the Tuareg do not explicitly report decadal trends in the frequency of extreme events. The differential perception of climate change impacts across scales can have important implications for undertaking climate change adaptation measures

Quantized Nambu-Poisson Manifolds in a 3-Lie Algebra Reduced Model

We consider dimensional reduction of the Bagger-Lambert-Gustavsson theory to a zero-dimensional 3-Lie algebra model and construct various stable solutions corresponding to quantized Nambu-Poisson manifolds. A recently proposed Higgs mechanism reduces this model to the IKKT matrix model. We find that in the strong coupling limit, our solutions correspond to ordinary noncommutative spaces arising as stable solutions in the IKKT model with D-brane backgrounds. In particular, this happens for S^3, R^3 and five-dimensional Neveu-Schwarz Hpp-waves. We expand our model around these backgrounds and find effective noncommutative field theories with complicated interactions involving higher-derivative terms. We also describe the relation of our reduced model to a cubic supermatrix model based on an osp(1|32) supersymmetry algebra.Comment: 22 page

String Theory on Dp-plane waves

We study the spectrum of solvable string models on plane waves descending from non-conformal Dp-brane geometries. We mainly focus on S-dual F1/D1-waves in type IIB and type I/heterotic 10D superstrings. We derive the Kaluza-Klein spectrum of N=1,2 10D supergravities on D1/F1-waves. We compute helicity supertraces counting multiplicities and R-charges of string excitations in the plane wave geometry. The results are compared against the expectations coming from gauge/supergravity descriptions. In the type I case, the Klein, Annulus and Moebius one-loop amplitudes are computed for ten-dimensional D1-waves. We test the consistency of the open string descendant by showing that after modular transformations to the closed string channel, the three amplitudes combine themselves to reconstruct a complete square (|B>+|C>)^2. Tadpole conditions are also discussed.Comment: 22 pages, Minor corrections, References adde