Répertoire et contextes sociaux des cris unitaires du colobe vert (procolobus verus) dans le Parc National de Taï (PNT), Côte d\'Ivoire

Pour caractériser l\'environnement social et écologique du Colobe Vert (Procolobus verus), des observations régulières par tranche de 15 minutes d\'animaux focaux dans trois groupes ont été méné. Les observations et les enregistrements de cris occasionnels (Ad libitum) ont permis de répertorier huit (8) types de cris unitaires émis par différentes classes de sexes et d\'âges. Ces cris peuvent être regroupés en quatre catégories selon les contextes sociaux dans lesquels ils interviennent : les cris a, b et c en cas de prédation et de trouble (présence de prédateur, cris d\'alarme d\'autres espèces), les cris f et g en situation de conflit (combat entre individus), les cris b, c et e en contexte de stabilité (calme apparent), et les cris b, c et e pour signaler des rencontres inter-groupes (rencontre avec d\'autres groupes de singes).In order to knod how Olive Colobus monkeys (Procolobus verus) interact with their social and ecological environment, we carried out regular observations by 15 minutes old section of focal animals in three groups. These observations associated with the recordings of occasional calls (Ad libitum) enabled us to index eight (8) types of unit calls emitted by various sex and age classes. These calls can be gathered into four types according to social contexts in which they happened : the calls a, b and c in context of predation and disturbance (presence of predator, alarm calls from other monkey species), the calls f and g in a situation of conflict (fights between individual), the calls b, c and e as a signal of stability (peaceful context), and the calls b, c and e in case of intergroup encounters (encounter with other monkey groups). Keywords: Colobe Vert, vocalisation, cri unitaire, contexte social, communication, Parc National de Taï, Côte d'Ivoire.Olive Colobus, vocalization, unit call, social context, communication, Taï National Park, Ivory Coast.Sciences & Nature Vol. 4 (2) 2007: pp. 137-14

Dynactin1 depletion leads to neuromuscular synapse instability and functional abnormalities.

Dynactin subunit 1 is the largest subunit of the dynactin complex, an activator of the molecular motor protein complex dynein. Reduced levels of DCTN1 mRNA and protein have been found in sporadic amyotrophic lateral sclerosis (ALS) patients, and mutations have been associated with disease, but the role of this protein in disease pathogenesis is still unknown. We characterized a Dynactin1a depletion model in the zebrafish embryo and combined in vivo molecular analysis of primary motor neuron development with live in vivo axonal transport assays in single cells to investigate ALS-related defects. To probe neuromuscular junction (NMJ) function and organization we performed paired motor neuron-muscle electrophysiological recordings and GCaMP calcium imaging in live, intact larvae, and the synapse structure was investigated by electron microscopy. Here we show that Dynactin1a depletion is sufficient to induce defects in the development of spinal cord motor neurons and in the function of the NMJ. We observe synapse instability, impaired growth of primary motor neurons, and higher failure rates of action potentials at the NMJ. In addition, the embryos display locomotion defects consistent with NMJ dysfunction. Rescue of the observed phenotype by overexpression of wild-type human DCTN1-GFP indicates a cell-autonomous mechanism. Synaptic accumulation of DCTN1-GFP, as well as ultrastructural analysis of NMJ synapses exhibiting wider synaptic clefts, support a local role for Dynactin1a in synaptic function. Furthermore, live in vivo analysis of axonal transport and cytoskeleton dynamics in primary motor neurons show that the phenotype reported here is independent of modulation of these processes. Our study reveals a novel role for Dynactin1 in ALS pathogenesis, where it acts cell-autonomously to promote motor neuron synapse stability independently of dynein-mediated axonal transport

The diurnal primate community of the Tanoé Forest: species composition, relative abundance, distribution, polyspecific associations and conservation status

The Tanoé Forest is located within the original distribution area of the Miss Waldron red colobus (Piliocolobus badius waldronae), the diana roloway (Cercopithecus diana roloway) and the white napped mangabey (Cercocebus atys lunulatus). These three monkey species are classified by IUCN among the 25 most threatened monkeys of the world. Surveys conducted in their believed distribution area in Côte d’Ivoire from 2004 to 2007 highlighted an advanced degradation of habitats, an intensive hunting activity and a subsequent local extinction of some primate species. Field survey conducted in the Tanoé Swamp Forest shown that there is an exception in this dramatic context since this forest still housing threatened species such as the Diana roloway, the white-napped mangabey, and other monkeys of conservation concern: the Geoffroy’s colobus (Colobus vellerosus) and the olive colobus (Procolobus verus), and probably a viable Miss Waldron monkeys population (Piliocolobus waldronae). In addition, this forest hosts the Lowe’s guenon (Cercopithecus campbelli lowei) and the lesser spot-nosed guenon (Cercopithecus petaurista petaurista), that are widespread in the Tanoé Swamp Forest.Keywords: Tanoé forest, primate community, endangered, Swamp Forest, distributio

In Vivo Validation of a Computationally Predicted Conserved Ath5 Target Gene Set

So far, the computational identification of transcription factor binding sites is hampered by the complexity of vertebrate genomes. Here we present an in silico procedure to predict target sites of a transcription factor in complex genomes using its binding site. In a first step sequence, comparison of closely related genomes identifies the binding sites in conserved cis-regulatory regions (phylogenetic footprinting). Subsequently, more remote genomes are introduced into the comparison to identify highly conserved and therefore putatively functional binding sites (phylogenetic filtering). When applied to the binding site of atonal homolog 5 (Ath5 or ATOH7), this procedure efficiently filters evolutionarily conserved binding sites out of more than 300,000 instances in a vertebrate genome. We validate a selection of the linked target genes by showing coexpression with and transcriptional regulation by Ath5. Finally, chromatin immunoprecipitation demonstrates the occupancy of the target gene promoters by Ath5. Thus, our procedure, applied to whole genomes, is a fast and predictive tool to in silico filter the target genes of a given transcription factor with defined binding site

Properties of excitations in systems with a spinor Bose-Einstein condensate

General theory in case of homogenous Bose-Einstein condensed systems with spinor condensate is presented for the correlation functions of density and spin fluctuations and for the one-particle propagators as well. The random phase approximation is investigated and the damping of the modes is given in the intermediate temperature region. It is shown that the collective and the one-particle excitation spectra do not coincide fully.Comment: 5 pages, 1 figur

Properties of the Volume Operator in Loop Quantum Gravity I: Results

We analyze the spectral properties of the volume operator of Ashtekar and Lewandowski in Loop Quantum Gravity, which is the quantum analogue of the classical volume expression for regions in three dimensional Riemannian space. Our analysis considers for the first time generic graph vertices of valence greater than four. Here we find that the geometry of the underlying vertex characterizes the spectral properties of the volume operator, in particular the presence of a `volume gap' (a smallest non-zero eigenvalue in the spectrum) is found to depend on the vertex embedding. We compute the set of all non-spatially diffeomorphic non-coplanar vertex embeddings for vertices of valence 5--7, and argue that these sets can be used to label spatial diffeomorphism invariant states. We observe how gauge invariance connects vertex geometry and representation properties of the underlying gauge group in a natural way. Analytical results on the spectrum on 4-valent vertices are included, for which the presence of a volume gap is proved. This paper presents our main results; details are provided by a companion paper arXiv:0706.0382v1.Comment: 36 pages, 7 figures, LaTeX. See also companion paper arXiv:0706.0382v1. Version as published in CQG in 2008. See arXiv:1003.2348 for important remarks regarding the sigma configurations. Subsequent computations have revealed some minor errors, which do not change the qualitative results but modify some of the numbers presented her

Dielectric formalism and damping of collective modes in trapped Bose-Einstein condensed gases

We present the general dielectric formalism for Bose-Einstein condensed systems in external potential at finite temperatures. On the basis of a model arising within this framework as a first approximation in an intermediate temperature region for large condensate we calculate the damping of low-energy excitations in the collisionless regime.Comment: 4 pages, no figures, RevTe

Shifts and widths of collective excitations in trapped Bose gases by the dielectric formalism

We present predictions for the temperature dependent shifts and damping rates. They are obtained by applying the dielectric formalism to a simple model of a trapped Bose gas. Within the framework of the model we use lowest order perturbation theory to determine the first order correction to the results of Hartree-Fock-Bogoliubov-Popov theory for the complex collective excitation frequencies, and present numerical results for the temperature dependence of the damping rates and the frequency shifts. Good agreement with the experimental values measured at JILA are found for the m=2 mode, while we find disagreements in the shifts for m=0. The latter point to the necessity of a non-perturbative treatment for an explanation of the temperature-dependence of the m=0 shifts.Comment: 10 pages revtex, 3 figures in postscrip

A prospective observational study of bacteraemia in adults admitted to an urban Mozambican hospital

Background. Bacteraemia is a common cause of fever among patients presenting to hospitals in  sub-Saharan Africa. The worldwide rise of antibiotic resistance makes empirical therapy increasingly  difficult, especially in resource-limited settings.Objectives. To describe the incidence of bacteraemia in febrile adults presenting to Maputo Central Hospital (MCH), an urban referral hospital in the capital of Mozambique, and characterise the causative  organisms and antibiotic susceptibilities. We aimed to describe the antibiotic prescribing habits of local doctors, to identify areas for quality improvement.Methods. Inclusion criteria were: (i) .18 years of age; (ii) axillary temperature .38‹C or .35‹C; (iii) admission to MCH medical wards in the past 24 hours; and (iv) no receipt of antibiotics as an inpatient. Blood cultures were drawn from enrolled patients and incubated using the BacT/Alert automated system (bioMerieux, France). Antibiotic susceptibilities were tested using the Kirby-Bauer disc diffusion method.Results. Of the 841 patients enrolled, 63 (7.5%) had a bloodstream infection. The most common isolates were Staphylococcus aureus, Escherichia coli, and non-typhoidal Salmonella. Antibiotic resistance was common, with 20/59 (33.9%) of all bacterial isolates showing resistance to ceftriaxone, the broadest-spectrum antibiotic commonly available at MCH. Receipt of insufficiently broad empirical antibiotics was associated with poor in-hospital outcomes (odds ratio 8.05; 95% confidence interval 1.62 - 39.91;  p=0.04).Conclusion. This study highlights several opportunities for quality improvement, including educating doctors to have a higher index of suspicion for bacteraemia, improving local antibiotic guidelines,  improving communication between laboratory and doctors, and increasing the supply of some key antibiotics

Mechanically activated rupture of single covalent bonds: evidence of force induced bond hydrolysis.

We have used temperature-dependent single molecule force spectroscopy to stretch covalently anchored carboxymethylated amylose (CMA) polymers attached to an amino-functionalized AFM cantilever. Using an Arrhenius kinetics model based on a Morse potential as a one-dimensional representation of covalent bonds, we have extracted kinetic and structural parameters of the bond rupture process. With 35.5 kJ mol−1, we found a significantly smaller dissociation energy and with 9.0 × 102 s−1 to 3.6 × 103 s−1 also smaller Arrhenius pre-factors than expected for homolytic bond scission. One possible explanation for the severely reduced dissociation energy and Arrhenius pre-factors is the mechanically activated hydrolysis of covalent bonds. Both the carboxylic acid amide and the siloxane bond in the amino-silane surface linker are in principle prone to bond hydrolysis. Scattering, slope and curvature of the scattered data plots indicate that in fact two competing rupture mechanisms are observed