Future of Thailand's captive elephants: commentary on Baker & Winkler on elephant rewilding

Removal from natural habitat and commodification as private property compromise elephants’ broader societal value. Although we support Baker & Winkler’s (2020) plea for a new community-based rewilding conservation model focused on mahout culture, we recommend an expanded co-management approach to complement and enhance the regional elephant conservation strategy with additional local community stakeholders and the potential to extend across international borders into suitable elephant habitat. Holistic co-management approaches improve human wellbeing and social cohesion, as well as elephant wellbeing, thereby better securing long-term survival of Asian elephants, environmental justice, and overall sustainability

Density-functional study of defects in two-dimensional circular nematic nanocavities

We use density--functional theory to study the structure of two-dimensional defects inside a circular nematic nanocavity. The density, nematic order parameter, and director fields, as well as the defect core energy and core radius, are obtained in a thermodynamically consistent way for defects with topological charge $k=+1$ (with radial and tangential symmetries) and $k=+1/2$. An independent calculation of the fluid elastic constants, within the same theory, allows us to connect with the local free--energy density predicted by elastic theory, which in turn provides a criterion to define a defect core boundary and a defect core free energy for the two types of defects. The radial and tangential defects turn out to have very different properties, a feature that a previous Maier--Saupe theory could not account for due to the simplified nature of the interactions --which caused all elastic constants to be equal. In the case with two $k=+1/2$ defects in the cavity, the elastic r\'egime cannot be reached due to the small radii of the cavities considered, but some trends can already be obtained.Comment: 9 figures. Accepted for publication in liquid crystal

Conformation of Circular DNA in 2 Dimensions

The conformation of circular DNA molecules of various lengths adsorbed in a 2D conformation on a mica surface is studied. The results confirm the conjecture that the critical exponent $\nu$ is topologically invariant and equal to the SAW value (in the present case $\nu=3/4$), and that the topology and dimensionality of the system strongly influences the cross-over between the rigid regime and the self-avoiding regime at a scale $L\approx 8 \ell_p$. Additionally, the bond correlation function scales with the molecular length $L$ as predicted. For molecular lengths $L\leq5 \ell_p$, circular DNA behaves like a stiff molecule with approximately elliptic shape.Comment: 4 pages, 5 figure

On a simple criterion for the existence of a principal eigenfunction of some nonlocal operators

In this paper we are interested in the existence of a principal eigenfunction of a nonlocal operator which appears in the description of various phenomena ranging from population dynamics to micro-magnetism. More precisely, we study the following eigenvalue problem: \int_{\O}J(\frac{x-y}{g(y)})\frac{\phi(y)}{g^n(y)}\, dy +a(x)\phi =\rho \phi, where \O\subset\R^n is an open connected set, $J$ a nonnegative kernel and $g$ a positive function. First, we establish a criterion for the existence of a principal eigenpair $(\lambda_p,\phi_p)$. We also explore the relation between the sign of the largest element of the spectrum with a strong maximum property satisfied by the operator. As an application of these results we construct and characterize the solutions of some nonlinear nonlocal reaction diffusion equations

Interstellar absorptions towards the LMC: Small-scale density variations in Milky Way disc gas

Observations show that the ISM contains sub-structure on scales less than 1 pc, detected in the form of spatial and temporal variations in column densities or optical depth. Despite the number of detections, the nature and ubiquity of the small-scale structure in the ISM is not yet fully understood. We use UV absorption data mainly from FUSE and partly from STIS of six LMC stars (Sk-67{\deg}111, LH54-425, Sk-67{\deg}107, Sk-67{\deg}106, Sk-67{\deg}104, and Sk-67{\deg}101), all located within 5 arcmin of each other, and analyse the physical properties of the Galactic disc gas in front of the LMC on sub-pc scales. We analyse absorption lines of a number of ions within the UV spectral range. Most importantly, interstellar molecular hydrogen, neutral oxygen, and fine-structure levels of neutral carbon have been used in order to study changes in the density and the physical properties of the Galactic disc gas over small angular scales. While most species do not show any significant variation in their column densities, we find an enhancement of almost 2 dex for H_2 from Sk-67{\deg}111 to Sk-67{\deg}101, accompanied by only a small variation in the OI column density. Based on the formation-dissociation equilibrium, we trace these variations to the actual density variations in the molecular gas. On the smallest spatial scale of < 0.08 pc, between Sk-67{\deg}107 and LH54-425, we find a gas density variation of a factor of 1.8. The line of sight towards LH54-425 does not follow the relatively smooth change seen from Sk-67{\deg}101 to Sk-67{\deg}111, suggesting that sub-structure might exist on a smaller spatial scale than the linear extent of our sight-lines. Our observations suggest that the detected H_2 in these six lines of sight is not necessarily physically connected, but that we are sampling molecular cloudlets with pathlengths < 0.1-1.8 pc and possibly different densities.Comment: 17 pages, 8 figures. Accepted for publication in A&

Palaeogeographic reconstruction in the transition zone : the role of geophysical forward modelling in ground investigation surveys

Geophysical survey techniques are commonly used as part of studies to reconstruct past geographies in archaeological and palaeoenvironmental landscape investigations onshore and offshore. However, their use across the intertidal zone for constructing contiguous models is far more challenging. In order to enhance the interpretation of the recovered data forward modelling is used here to demonstrate the effective use of a staged approach to site investigation. Examples of data from electrical and electromagnetic techniques have been modelled and tested with ground truth measurements including trial pits, coring and cone penetrometer testing. This combination of forward modelling and testing has proved to be particularly effective at mapping key geological situations of archaeological interest. The approach is demonstrated by reference to varying sub-surface sediment types exemplified by two field examples from the UK coast where typical palaeolandscape features, namely incised channels and deeply buried topographies are encountered. These palaeogeographic features were chosen as they have high potential for association with the evidence of past human activity.PostprintPeer reviewe

Channel Flow Studies Using Driftwood Density Analysis in Elger Bay, Camano Island, WA

Previous studies on Elger Bay, Camano Island, WA hypothesized that the bay has been emptying of stored driftwood since the 1970\u27s. To test this hypothesis, we conducted a research project using a combination of field data and historical imagery analysis with Google Earth and ArcGIS to mathematically compare the density of driftwood. Changes in driftwood area may indicate changes in sea level rise, bay subsidence, and/or anthropogenic activity. We found that the maximum driftwood extent was actually closer to the 1950\u27s than the 1970\u27s. In addition to overall extent we investigated the overall channel flow along Elger Bay by analyzing driftwood movement over time. Using data from different months and years, we were able to compare development of driftwood to analyze the channel flow. Our results indicate that the driftwood is mobile both in the front and back of the bay with annual changes in driftwood area and extent. There is also continuous movement of driftwood along major channels, resulting in changes in the geometry of the driftwood field. We expected to see movement along major channels and in the front of the bay; and driftwood in the back to be stationary. The numerical data disproved the hypothesis that the driftwood area reached a maximum in the 1970s and has been emptying since. Our other observations were consistent with our hypotheses, except for the mobility of driftwood in the back of the bay

Energy considerations for a superlens based on metal/dielectric multilayers

We investigate the resolution and absorption losses of a Ag/GaP multilayer superlens. For a fixed source to image distance the resolution is independent of the position of the lens but the losses depend strongly on the lens placement. The absorption losses associated with the evanescent waves can be significantly larger than losses associated with the propagating waves especially when the superlens is close to the source. The interpretation of transmittance values greater than unity for evanescent waves is clarified with respect to the associated absorption losses.Comment: to be published in Optics Expres

Supersymmetric solutions of N=2 d=4 sugra: the whole ungauged shebang

In this article we complete the classification of the supersymmetric solutions of N=2 D=4 ungauged supergravity coupled to an arbitrary number of vector- and hypermultiplets. We find that in the timelike case the hypermultiplets cause the constant-time hypersurfaces to be curved and have su(2) holonomy identical to that of the hyperscalar manifold. The solutions have the same structure as without hypermultiplets but now depend on functions which are harmonic in the curved 3-dimensional space. We discuss an example obtained from a hyper-less solution via the c-map. In the null case we find that the hyperscalars can only depend on the null coordinate and the solutions are essentially those of the hyper-less case.Comment: 27 pages, latex2

Fractional Hamiltonian Monodromy from a Gauss-Manin Monodromy

Fractional Hamiltonian Monodromy is a generalization of the notion of Hamiltonian Monodromy, recently introduced by N. N. Nekhoroshev, D. A. Sadovskii and B. I. Zhilinskii for energy-momentum maps whose image has a particular type of non-isolated singularities. In this paper, we analyze the notion of Fractional Hamiltonian Monodromy in terms of the Gauss-Manin Monodromy of a Riemann surface constructed from the energy-momentum map and associated to a loop in complex space which bypasses the line of singularities. We also prove some propositions on Fractional Hamiltonian Monodromy for 1:-n and m:-n resonant systems.Comment: 39 pages, 24 figures. submitted to J. Math. Phy