Newly-Discovered Globular Clusters in NGC 147 and NGC 185 from PAndAS

Using data from the Pan-Andromeda Archaeological Survey (PAndAS), we have discovered four new globular clusters (GCs) associated with the M31 dwarf elliptical (dE) satellites NGC 147 and NGC 185. Three of these are associated with NGC 147 and one with NGC 185. All lie beyond the main optical boundaries of the galaxies and are the most remote clusters yet known in these systems. Radial velocities derived from low resolution spectra are used to argue that the GCs are bound to the dwarfs and are not part of the M31 halo population. Combining PAndAS with UKIRT/WFCAM data, we present the first homogeneous optical and near-IR photometry for the entire GC systems of these dEs. Colour-colour plots and published colour-metallicity relations are employed to constrain GC ages and metallicities. It is demonstrated that the clusters are in general metal poor ([Fe/H] < -1.25 dex), while the ages are more difficult to constrain. The mean (V-I)$_0$ colours of the two GC systems are very similar to those of the GC systems of dEs in the Virgo and Fornax clusters, as well as the extended halo GC population in M31. The new clusters bring the GC specific frequency (S_N) to ~9 in NGC 147 and ~5 in NGC 185, consistent with values found for dEs of similar luminosity residing in a range of environments.Comment: 14 pages, 6 figures, 6 tables, accepted for publication in MNRA

Individual-based modelling of elephant population dynamics using remote sensing to estimate food availability

Strategies for the conservation and management of many wild species requires an improved understanding of how population dynamics respond to changes in environmental conditions, including key drivers such as food availability. The development of mechanistic predictive models, in which the underlying processes of a system are modelled, enables a robust understanding of these demographic responses to dynamic environmental conditions. We present an individual-based energy budget model for a mega-herbivore, the African elephant (Loxodonta africana), which relates remotely measured changes in food availability to vital demographic rates of birth and mortality. Elephants require large spaces over which to roam in search of seasonal food, and thus are vulnerable to environmental changes which limit space use or alter food availability. The model is constructed using principles of physiological ecology; uncertain parameter values are calibrated using approximate Bayesian computation. The resulting model fits observed population dynamics data well. The model has critical value in being able to project elephant population size under future environmental conditions and is applicable to other mammalian herbivores with appropriate parameterisation

Human‐driven habitat conversion is a more immediate threat to Amboseli elephants than climate change

Global ecosystem change presents a major challenge to biodiversity conservation, which must identify and prioritize the most critical threats to species persistence given limited available funding. Mechanistic models enable robust predictions under future conditions and can consider multiple stressors in combination. Here we use an individual‐based model (IBM) to predict elephant population size in Amboseli, southern Kenya, under environmental scenarios incorporating climate change and anthropogenic habitat loss. The IBM uses projected food availability as a key driver of elephant population dynamics and relates variation in food availability to changes in vital demographic rates through an energy budget. Habitat loss, rather than climate change, represents the most significant threat to the persistence of the Amboseli elephant population in the 21st century and highlights the importance of collaborations and agreements that preserve space for Amboseli elephants to ensure the population remains resilient to environmental stochasticity

Self-organization of (001) cubic crystal surfaces

Self-organization on crystal surface is studied as a two dimensional spinodal decomposition in presence of a surface stress. The elastic Green function is calculated for a $(001)$ cubic crystal surface taking into account the crystal anisotropy. Numerical calculations show that the phase separation is driven by the interplay between domain boundary energy and long range elastic interactions. At late stage of the phase separation process, a steady state appears with different nanometric patterns according to the surface coverage and the crystal elastic constants

The upgrading of fire safety in historic buildings

There is a seemingly continual erosion of our cultural heritage due to fires in historic buildings. Some of these fires result in partial loss of the asset, some result in total loss – in all cases irreplaceable historic fabric is destroyed. Accurate recording for fires in historic buildings is problematic, but such data as has been collated indicates that the level of loss is high. One of the key factors in achieving robust fire safety in historic buildings is the upgrading of physical fire protection measures. It has been suggested that we should assume a fire event is probable, and together with a context in which outside help might be some time in arriving, such measures are considered crucial in containing the fire and raising the alarm as quickly as possible. This article considers passive and active fire protection measures, using case study material to provide illustrative examples. Where it might be expected that conservation requirements, aiming to avoid negative impact to character and significance, might hinder disruptive physical interventions to improve fire protection, in fact a great deal can be achieved. Such a pragmatic approach is arguably necessary for the safety and preservation of built heritage, when the alternative might otherwise be yet another burnt-out shell

Newly discovered globular clusters in NGC 147 and NGC 185 from PAndAS

Using data from the Pan-Andromeda Archaeological Survey (PAndAS), we have discovered four new globular clusters (GCs) associated with the M31 dwarf elliptical (dE) satellites NGC 147 and NGC 185. Three of these are associated with NGC 147 and one with NG

Movement patterns of forest elephants (Loxodonta cyclotis Matschie, 1900) in the Odzala-Kokoua National Park, Republic of Congo

[Otros] Les éléphants de forêt d'Afrique (Loxodonta cyclotis Matschie, 1900) sont des ingénieurs en écologie qui jouent un rôle fondamental dans la dynamique de la végétation. L'espèce constitue une préoccupation immédiate pour la conservation, mais elle est relativement peu étudiée. Pour combler cette lacune de connaissances, nous avons étudié les facteurs de déplacements quotidiens (déplacements linéaires) des éléphants de forêt ¿ caractérisés par un ensemble de variables géographiques, météorologiques et anthropiques ¿ dans le Parc National d'Odzala¿Kokoua, en République du Congo. Concrètement, nous avons utilisé la forêt d'arbres décisionnels pour modéliser et démêler les principaux facteurs environnementaux régissant les déplacements de six éléphants de forêt, équipés de colliers GPS et suivis pendant 16 mois. Les résultats ont montré que les femelles se déplaçaient plus loin que les mâles, tandis que la présence de routes ou d¿établissements humains perturbait le comportement des éléphants, ce qui accélérait les déplacements. Les éléphants de forêt se déplaçaient plus rapidement dans les cours d¿eau et dans les forêts dont le sous¿bois était dominé par les forêts de Marantaceae et les bais, mais se déplaçait plus lentement dans les savanes. Enfin, les zones inondables ¿ characterisées par l¿altitude et les précipitations accumulées ¿ et les températures plus élevées empêchaient des déplacements plus longs. Nous espérons que ces résultats amélioreront les connaissances sur les mouvements des espèces à travers différents habitats, ce qui serait bénéfique pour la gestion de leur conservation.[EN] African forest elephants (Loxodonta cyclotis Matschie, 1900) are ecological engineers that play a fundamental role in vegetation dynamics. The species is of immediate conservation concern, yet it is relatively understudied. To narrow this knowledge gap, we studied the drivers of daily movement patterns (linear displacements) of forest elephants¿characterised by a set of geographical, meteorological and anthropogenic variables¿in the Odzala¿Kokoua National Park, Republic of Congo. Explicitly, we used conditional random forest to model and disentangle the main environmental factors governing the displacements of six forest elephants,fitted with GPS collars and tracked over 16 months. Results indicated that females moved further distances than males, while the presence of roads or human settlements disrupted elephant behaviour resulting in faster displacements. Forest elephants moved faster along watercourses and through forest with understory dominated by Marantaceae forests and bais, but moved slower in savannahs. Finally, flood¿prone areas¿described by elevation and accumulated precipitation¿and higher temperatures prevented longer displacements. We expect these results to improve the knowledge on the species movements through different habitats, which would benefit its conservation management.The fieldwork was financed by African Parks. We are grateful to the Congolese wildlife authorities (Ministère de l'Économie Forestière et de l'Environnement) for the permission to carry out this study, and we are deeply indebted to the director of the OKNP and to the conservation, wildlife monitoring and research manager, Erik Marav, respectively, for their continued support during our study. We are particularly grateful to Dr. Mike Kock, veterinarian, for collaring the elephants and to the field tracking team. We are also grateful to Séan Cahill for the useful comments and English correction that helped improve this manuscript. 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The outer halo globular cluster system of M31 - I. the final PAndAS catalogue

We report the discovery of 59 globular clusters (GCs) and two candidate GCs in a search of the halo of M31, primarily via visual inspection of Canada-France-Hawaii Telescope/MegaCam imagery from the Pan-Andromeda Archaeological Survey (PAndAS). The superior quality of these data also allows us to check the classification of remote objects in the Revised Bologna Catalogue (RBC), plus a subset of GC candidates drawn from Sloan Digital Sky Survey (SDSS) imaging. We identify three additional new GCs from the RBC, and confirm the GC nature of 11 SDSS objects (8 of which appear independently in our remote halo catalogue); the remaining 188 candidates across both lists are either foreground stars or background galaxies. Our new catalogue represents the first uniform census of GCs across the M31 halo - we find clusters to the limit of the PAndAS survey area at projected radii of up to Rproj ~ 150 kpc. Tests using artificial clusters reveal that detection incompleteness cuts in at luminosities below MV = -6.0; our 50 per cent completeness limit is MV ≈ -4.1. We construct a uniform set of PAndAS photometric measurements for all known GCs outside Rproj = 25 kpc, and any new GCs within this radius. With these data, we update results from Huxor et al., investigating the luminosity function (LF), colours and effective radii of M31 GCs with a particular focus on the remote halo.We find that the GCLF is clearly bimodal in the outer halo (Rproj > 30 kpc), with the secondary peak at MV ~ -5.5. We argue that the GCs in this peak have most likely been accreted along with their host dwarf galaxies. Notwithstanding, we also find, as in previous surveys, a substantial number of GCs with above-average luminosity in the outer M31 halo - a population with no clear counterpart in the Milky Way

Selective nanomanipulation using optical forces

We present a detailed theoretical study of the recent proposal for selective nanomanipulation of nanometric particles above a substrate using near-field optical forces [Chaumet {\it et al.} Phys. Rev. Lett. {\bf 88}, 123601 (2002)]. Evanescent light scattering at the apex of an apertureless near-field probe is used to create an optical trap. The position of the trap is controlled on a nanometric scale via the probe and small objects can be selectively trapped and manipulated. We discuss the influence of the geometry of the particles and the probe on the efficiency of the trap. We also consider the influence of multiple scattering among the particles on the substrate and its effect on the robustness of the trap.Comment: 12 pages, 17 figure