The structure of the asteroid 4 Vesta as revealed by models of planet-scale collisions.

Asteroid 4 Vesta seems to be a major intact protoplanet, with a surface composition similar to that of the HED (howardite-eucrite-diogenite) meteorites. The southern hemisphere is dominated by a giant impact scar, but previous impact models have failed to reproduce the observed topography. The recent discovery that Vesta's southern hemisphere is dominated by two overlapping basins provides an opportunity to model Vesta's topography more accurately. Here we report three-dimensional simulations of Vesta's global evolution under two overlapping planet-scale collisions. We closely reproduce its observed shape, and provide maps of impact excavation and ejecta deposition. Spiral patterns observed in the younger basin Rheasilvia, about one billion years old, are attributed to Coriolis forces during crater collapse. Surface materials exposed in the north come from a depth of about 20 kilometres, according to our models, whereas materials exposed inside the southern double-excavation come from depths of about 60-100 kilometres. If Vesta began as a layered, completely differentiated protoplanet, then our model predicts large areas of pure diogenites and olivine-rich rocks. These are not seen, possibly implying that the outer 100 kilometres or so of Vesta is composed mainly of a basaltic crust (eucrites) with ultramafic intrusions (diogenites).

Cell division and death inhibit glassy behaviour of confluent tissues.

We investigate the effects of cell division and apoptosis on collective dynamics in two-dimensional epithelial tissues. Our model includes three key ingredients observed across many epithelia, namely cell-cell adhesion, cell death and a cell division process that depends on the surrounding environment. We show a rich non-equilibrium phase diagram depending on the ratio of cell death to cell division and on the adhesion strength. For large apoptosis rates, cells die out and the tissue disintegrates. As the death rate decreases, however, we show, consecutively, the existence of a gas-like phase, a gel-like phase, and a dense confluent (tissue) phase. Most striking is the observation that the tissue is self-melting through its own internal activity, ruling out the existence of any glassy phase.

Production and calibration of the second batch of OIE anti-rabies positive reference serum.

The Biological Standards Commission of the World Organisation for Animal Health (OIE) oversees the preparation and validation of OIE-approved International Reference Standards for use in serological assays for detecting infectious diseases of animals or the adequacy of their immune response following vaccination against those diseases. The principal use of OIE-approved International Reference Standards is to harmonise serological testing and to promote the mutual recognition of test results for international trade. In the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, the organisation recommends the use of the OIE anti-rabies positive reference serum of dog origin to titrate serum samples in international units (IU)/ml for use in rabies serological tests. The first batch of OIE reference serum of dog origin was produced in1991 and was used internationally until the beginning of 2010. The preparation of the new batch began in 2012 and, in contrast to the previous batch, three commercial inactivated rabies vaccines based on the most frequently used vaccine strains (Pasteur Virus and Flury Low Egg Passage) were selected for the immunisation of dogs in accordance with OIE guidelines. In 2013, calibration was completed through an inter-laboratory test involving five OIE Reference Laboratories for Rabies with the Second World Health Organization (WHO) International Standard for Anti-Rabies Immunoglobulin being used as a reference standard in this calibration. After statistical analysis of the results, the consensus titre was established as 5.59 IU/ml. The technical and statistical data were submitted to the OIE for assessment. In February 2014, the OIE Biological Standards Commission adopted this serum as an OIE-approved standard reagent for rabies serology.

La Commission des normes biologiques de l'Organisation mondiale de la santé animale (OIE) supervise la préparation et la validation de réactifs internationaux de référence approuvés par l'OIE et destinés aux épreuves sérologiques ayant pour objet le diagnostic des maladies infectieuses des animaux ou le suivi de l'effet protecteur obtenu par la vaccination contre ces maladies. Les réactifs internationaux de référence approuvés par l'OIE sont principalement utilisés pour harmoniser les tests sérologiques et permettre la reconnaissance mutuelle des résultats des tests dans le cadre des échanges internationaux. Le Manuel des tests de diagnostic et des vaccins pour les animaux terrestres de l'OIE recommande d'utiliser le sérum de référence antirabique positif d'origine canine de l'OIE pour exprimer le titre des échantillons de sérum analysés en unités internationales (UI)/ml lors des épreuves sérologiques. Le premier lot de sérum de référence d'origine canine de l'OIE, produit en 1991, a été utilisé à l'échelle internationale jusqu'au début de l'année 2010. La préparation d'un nouveau lot a commencé en 2012 et, contrairement au lot précédent, trois vaccins antirabiques inactivés disponibles dans le commerce, basés sur les souches vaccinales les plus utilisées dans le monde (souche Pasteur et souche Flury Low Egg Passage) ont été choisis pour l'immunisation des chiens, conformément aux lignes directrices de l'OIE. L'étalonnage s'est achevé en 2013 lors d'un essai inter-laboratoires auquel ont participé cinq Laboratoires de référence de l'OIE pour la rage ; le second étalon international pour l'immunoglobuline antirabique de l'Organisation mondiale de la santé (OMS) a été utilisé en tant que réactif de référence pour cet étalonnage. Après analyse statistique des résultats, le titre consensuel obtenu est de 5,59 UI/ml. Les données techniques et statistiques ont été soumises à l'OIE pour évaluation. En février 2014, la Commission des normes biologiques de l'OIE a adopté ce sérum en tant qu'étalon de référence approuvé par l'OIE pour la sérologie de la rage.

La Comisión de Normas Biológicas de la Organización Mundial de Sanidad Animal (OIE) supervisa la preparación y validación de patrones de referencia internacional aprobados por la OIE para su utilización en ensayos serológicos destinados a detectar enfermedades animales infecciosas o a valorar la idoneidad de la respuesta inmunitaria de un animal al ser vacunado contra una u otra enfermedad. Dichos patrones sirven sobre todo para armonizar la realización de pruebas serológicas y promover el reconocimiento mutuo de los resultados de las pruebas con fines de comercio internacional. En su Manual de las Pruebas de Diagnóstico y de las Vacunas para los Animales Terrestres, la OIE recomienda el empleo del suero positivo antirrábico de referencia de la OIE, de origen canino, para titular muestras de suero en unidades internacionales (UI)/ml y utilizarlas en pruebas serológicas de detección de la rabia. El primer lote de suero de referencia de la OIE procedente de perros fue elaborado en 1991 y estuvo en uso a nivel internacional hasta principios de 2010. La preparación del nuevo lote dio comienzo en 2012 y, a diferencia del lote anterior, para la inmunización del perro se seleccionaron tres vacunas inactivadas comerciales basadas en las cepas vacunales utilizadas con más frecuencia (virus Pasteur y cepa Flury Low Egg Passage), de conformidad con las directrices de la OIE. En 2013 culminó el proceso de calibración con una prueba interlaboratorios en la que intervinieron cinco Laboratorios de Referencia de la OIE para la rabia. En esta calibración se utilizó como patrón de referencia el segundo patrón internacional de inmunoglobulina antirrábica de la Organización Mundial de la Salud (OMS). Tras el análisis estadístico de los resultados, el título de consenso quedó fijado en 5,59 UI/ml. Los datos técnicos y estadísticos fueron sometidos a la valoración de la OIE, cuya Comisión de Normas Biológicas, en febrero de 2014, aprobó este suero como reactivo de referencia aprobado por la OIE para pruebas serológicas de detección de la rabia.

Stochastic circular persistent currents of exciton polaritons.

We monitor the orbital degree of freedom of exciton-polariton condensates confined within an optical trap and unveil the stochastic switching of persistent annular polariton currents under pulse-periodic excitation. Within an elliptical trap, the low-lying in energy polariton current states manifest as a two-petaled density distribution with a swirling phase. In the stochastic regime, the density distribution, averaged over multiple excitation pulses, becomes homogenized in the azimuthal direction. Meanwhile, the weighted phase, extracted from interference experiments, exhibits two compensatory jumps when varied around the center of the trap. Introducing a supplemental control optical pulse to break the reciprocity of the system enables the transition from a stochastic to a deterministic regime, allowing for controlled polariton circulation direction.

The accidental release of exotic species from breeding colonies and zoological collections.

Exotic species have often been introduced into a new country in zoological or botanical gardens or on game and fur farms. When accidentally or deliberately released, these alien species can become invasive and have negative impacts on native plant and animal communities and human activities. This article focuses on a selection of such invasive species: principally the American mink (Neovison vison), but also the coypu (Myocastor coypus), muskrat (Ondatra zibethicus), raccoon dog (Nyctereutes procyonoides), raccoon (Procyon lotor) and African sacred ibis (Threskiornis aethiopicus). In each of these cases, the authors describe the biological characteristics and life history of the species, in relation to its invasive capacity, the origins and establishment of non-native populations, the environmental consequences and possible control measures. The main negative impacts observed are the destruction of habitat, the introduction and/or spread of pathogens and changes in the composition of native communities with consequent effects on biodiversity.

Subclinical BCG-osis in a Captive Badger (Meles meles) with Lymphoma.

Subclinical systemic dissemination of Bacillus Calmette-Guérin (BCG) is described in a captive badger (Meles meles) with lymphoma. An adult female European badger was vaccinated per os with BCG and after 8 weeks post-mortem examination identified marked lymphadenomegaly and multinodular hepatic lesions. The histopathology and immunohistochemistry confirmed a multicentric T-cell lymphoma, associated with high BCG bacterial load in numerous tissues. The histology did not identify BCG-associated lesions. The scenario suggested that the T-cell lymphoma likely favoured the dissemination of the BCG ('BCG-osis'). Given that lymphoma is rare in badgers, this neoplasm should not interfere with the efficacy of large-scale vaccination programmes.

Formation of carbonates in the Tatahouine meteorite.

The Tatahouine meteorite, in southern Tunisia, shows terrestrial contamination that developed during 63 years of exposure on Earth's surface. Samples collected on the day of the fall in 1931 contained fractures, with no secondary minerals, whereas samples collected in 1994 contain calcite aggregates (70 to 150 micrometers) and rod-shaped forms (100 to 600 nanometers in length and 70 to 80 nanometers in diameter) on the fractures. Carbon isotope analysis of the carbonates within the Tatahouine meteorite [delta13C = -2.0 per mil Pee Dee belemnite standard (PDB)] and the underlying ground (delta13C = -3.2 per mil PDB) confirm their terrestrial origin.

Efficacy of a square presentation of V-RG vaccine baits in red fox, domestic dog and raccoon dog.

Oral vaccination programmes conducted in rabies infected countries from Eastern Europe and Eurasia should not be restricted to foxes but should target other major rabies vectors such as dogs and raccoon dogs as well. The objective of this experimental trial was to assess the protection induced by the vaccine by challenging these different species, which had been previously vaccinated intramuscularly with the square V-RG baits (produced in the US). Different parameters were evaluated such as attractiveness of the baits and induction of neutralising antibodies as an indicator for immunogenicity and protection after rabies challenge. The acceptability of the square bait was satisfactory in dogs, foxes and raccoon dogs, confirming previous laboratory and field studies conducted with the rectangular baits. Only one vaccinated dog out of nine seroconverted after vaccination and among them one dog died of rabies. Eight of ten vaccinated foxes seroconverted after vaccination and survived the rabies challenge. All vaccinated raccoon dogs seroconverted after challenge and all survived the challenge. These trials demonstrated that the square presentation of the V-RG vaccine was attractive, immunogenic and efficacious.

Experimental infection of foxes with European bat lyssaviruses type-1 and -2.

Experimental studies have been undertaken to assess the susceptibility of silver foxes to bat variants of rabies virus, namely European Bat Lyssaviruses (EBLVs). Both EBLV-1 and EBLV-2 have been isolated in European bats since 1954, in Eptesicus serotinus and Myotis species, respectively. Since 2000, the number of reported cases has increased largely due to the improvement of the surveillance of bat rabies virus throughout Europe. Although over >800 EBLVs cases have been reported in bats in Europe, EBLV-1 and -2 viruses are rarely reported to infect humans and terrestrial animals. The study presented here shows that the sensitivity of silver foxes is low when infected with EBLVs via the intramuscular route; in contrast all animals infected via intracranial inoculation succumbed to the experimental challenge. The mortality rate was 100% for both EBLV-1 (approximately 4.5 log) and EBLV-2 (approximately 3.0 log). This data suggests that the susceptibility of foxes to EBLV-1 and EBLV-2 is low and that the transmission (spillover) and adaptation of EBLVs from a bat to a fox may be theoretically possible but unlikely.

New steps in the control of canine rabies in India.

In India, about 20,000 people die of rabies every year. The dog is the main reservoir and transmitter of the disease. A pilot rabies control programme was launched in five Indian federal states in February, 2007. This initiative is led by the Animal Welfare Board of India (AWBI) federating many animal welfare organizations and the Ministry of Agriculture. It aims at creating a "Rabies Free India." The programme combines parenteral vaccination of accessible owned and stray dogs, spaying/neutering followed by parenteral vaccination and oral vaccination of inaccessible dogs. The freeze-dried vaccine SAG2, including the bait casing, was registered in India following successful evaluation of vaccine-bait safety and efficacy (by survival after virulent challenge) in captive Indian stray dogs in the Bhopal High Security Animal Disease Laboratory. Furthermore, bait acceptance was tested under both experimental and field conditions.

Infection of foxes by Echinococcocus multilocularis in urban and suburban areas of Nancy, France: influence of feeding habits and environment.

This study evaluated the impact of biological and environmental factors on the infection of red foxes (Vulpes vulpes) by Echinococcus multilocularis in an endemic area of north-east France. From January 2004 to April 2006, 127 foxes were examined for E. multilocularis and their stomach contents analysed. The effect of year, season, age, sex and urbanisation level on E. multilocularis presence was estimated using a General Linear Model (GLM) with logit link, (i.e. logistic regression). Urbanisation level was the only influencing factor, with a decreasing gradient from rural [54%, CI 95% (40-68)] to peri-urban [31%, CI 95% (15-52)] and urban area [4%, CI 95% (0.7-15)]. The consumption of Arvicola terrestris and Microtus sp., grassland species, the main presumed intermediate hosts of E. multilocularis, was studied by the same approach. The two species were consumed less in the urban area and more in autumn than in spring. Anthropogenic food consumption was linked to urbanisation and to age. The frequency of anthropogenic food consumption decreased in the rural area. A global model explaining the presence of E. multilocularis and including urbanisation level and diet was then elaborated. Independently of urbanisation, there was a suggestion of less E. multilocularis infection with anthropogenic food consumption. Red foxes consuming Microtus sp. and A. terrestris had higher worm burden than those that did not. The results suggest that the decreasing gradient observed from rural to urban area is linked to behaviour and feeding habits.

Molecular epidemiology identifies only a single rabies virus variant circulating in complex carnivore communities of the Serengeti.

Understanding the transmission dynamics of generalist pathogens that infect multiple host species is essential for their effective control. Only by identifying those host populations that are critical to the permanent maintenance of the pathogen, as opposed to populations in which outbreaks are the result of 'spillover' infections, can control measures be appropriately directed. Rabies virus is capable of infecting a wide range of host species, but in many ecosystems, particular variants circulate among only a limited range of potential host populations. The Serengeti ecosystem (in northwestern Tanzania) supports a complex community of wild carnivores that are threatened by generalist pathogens that also circulate in domestic dog populations surrounding the park boundaries. While the combined assemblage of host species appears capable of permanently maintaining rabies in the ecosystem, little is known about the patterns of circulation within and between these host populations. Here we use molecular phylogenetics to test whether distinct virus-host associations occur in this species-rich carnivore community. Our analysis identifies a single major variant belonging to the group of southern Africa canid-associated viruses (Africa 1b) to be circulating within this ecosystem, and no evidence for species-specific grouping. A statistical parsimony analysis of nucleoprotein and glycoprotein gene sequence data is consistent with both within- and between-species transmission events. While likely differential sampling effort between host species precludes a definitive inference, the results are most consistent with dogs comprising the reservoir of rabies and emphasize the importance of applying control efforts in dog populations.

Use of filter paper (FTA) technology for sampling, recovery and molecular characterisation of rabies viruses.

This study evaluates the feasibility of the use of the FTA Gene Guard System (a commercial product consisting of filter paper impregnated with patented chemicals supplied by the Whatman company) for the shipment, storage and detection of RNA rabies viruses by a simplified hemi-nested reverse transcriptase polymerase chain reaction. HnRT-PCR of the rabies virus nucleoprotein gene with specific primers showed that viral RNA extracted from crude infected tissues remained stable after fixation on the filter paper under diverse environmental conditions for at least 35 days. The sequence analysis of the products amplified from five out of the seven known genotypes of Lyssaviruses showed the stability of viral RNA viruses after fixation on the filter paper. Furthermore, the sensitivity of the hnRT-PCR following RNA fixation on the filter paper was equivalent to that of standard hnRT-PCR. In conclusion, the stability of viral RNA and the inactivation of infectivity make the FTA technology useful for the storage, transport, collection and subsequent molecular analysis of viral rabies RNA, facilitating epidemiological investigations in the field.

Means used for terrestrial rabies elimination in France and policy for rabies surveillance in case of re-emergence.

In France, the first case of wildlife rabies was detected in 1968, with the red fox (Vulpes vulpes) as reservoir and vector of terrestrial rabies. The last case was reported at the end of 1998. The maximum infected area amounted to 140,000 km2 in 1989 with a record number of 4,213 infected wild and domestic animals. The contaminated areas included various landscapes such as low populated farming areas and low mountainous areas as well as very densely populated areas and industrial areas contiguously urbanised. Oral vaccination of wildlife against rabies was implemented in 1986 and 1987 on limited areas treated by hand distribution and then helicopter distribution was implemented in 1988. The control of wildlife rabies was centralised at the country level in one institute for elaboration of baiting strategies, rabies surveillance network, laboratory investigations such as tetracycline and serological testing, vaccine titration and rabies diagnosis. Oral vaccination campaigns were organised in spring and in autumn by dropping annually 40 baits/km2. The following vaccine baits were used: SAD B19 from 1986 to 1992, SAG1/SAG2 from 1990 to 2003 and VRG from 1989 to 2003. A cost analysis study of the system of oral vaccination implemented in France demonstrated that it is beneficial compared to the traditional expenses of rabies control. Animal rabies prophylaxis has been progressively adapted to the disease free status of the country; the surveillance network for rabies is still working and an emergency procedure is in place in the event of a re-emergence of the disease in the context of high density fox populations.

Rabies diagnosis.

A reliable diagnosis of rabies can only be made based on laboratory examination of specimens collected from suspected animals. Without data from diagnostic tests, it is not possible to establish rabies control policies. These data are also necessary for evaluating the impact of control measures on the disease and to adapt veterinary and human health policies to the rabies situation. This paper presents the routine laboratory techniques for rabies diagnosis that are published and recommended by both the OIE and WHO and which form the basis of rabies surveillance. They are presented along with more recent techniques which have proved useful in epidemiological and phylogenetic studies. The first step in controlling a disease is to be able to identify it consistently. A reliable and sensitive diagnostic test is therefore essential for use in epidemiological studies and disease control. Reliable diagnosis is also needed by official medical and veterinary services to decide how to deal with infected humans or animals. Without knowing where rabies is present in a country, it is difficult to establish a solid, long-term control policy. A viral disease may be diagnosed on the basis of clinical signs or after laboratory examination. Clinical diagnosis is based on the observation of symptoms and on observation of specific or at least highly evocative signs. Laboratory tests reveal the presence of infection using either indirect or direct methods. The most frequently used indirect methods are based on serological testing. Direct methods aim to detect the virus itself, its proteins, genetic material or traces of its replication in tissues.

First oral vaccination of wildlife against rabies in Estonia.

Estonia is a small country, with many islands, that covers a total area of 45,000 km2 in the Baltic region. Rabies is widely distributed all over the country, even on some islands. The disease is maintained by two species: red foxes and raccoon dogs. In 2003, 813 cases of rabies were recorded with 315 cases in foxes and 362 cases in raccoon dogs; since 2002 the latter species has had the highest level of rabies infection among all animal species in Estonia. The measure used to control rabies is vaccination of dogs and cats, as they are the source on infection of humans. In Spring 2004, a limited trial of oral vaccination of wildlife was conducted. The goal of this was to train the actors who will be implicated in larger future campaigns. This trial was conducted on Vormsi island (92 km2), located 10 km away from the west coast. Oral vaccination was performed manually over three days with SAG2 baits (Virbac company, France), by three teams.

Bat rabies surveillance in France, from 1989 through May 2005.

In France, the passive surveillance of lyssaviruses in bats started in 1989, with the first positive case found in the East of the country. In 2000, the French bat rabies surveillance network in France was improved on the basis of the one used for the surveillance of fox rabies. The objectives of this network are to improve bat rabies surveillance by increasing the number of specimens and to provide an estimation of rabies incidence in bat populations across the country. The surveillance network is principally constituted by the network of local Veterinary Services and by the National Bat Conservationists Network (French Society for the Study and Protection of Mammals). From 1989 to through 2004, 21 autochtonous rabies cases were diagnosed out of the 934 French bat cadavers found. The laboratory techniques used for diagnosis, recommended by WHO and OIE, were fluorescent antibody test (FAT), rabies tissue culture infection test (RTCIT) on murine neuroblastoma cells, and the mouse inoculation test (MIT). All 21 cases were diagnosed in serotine bats (Eptesicus serotinus) and were due to European bat lyssavirus type 1 (EBLV-1), genotype 5, infection.

Plastic response and correlations in athermally sheared amorphous solids.

The onset of irreversible deformation in low-temperature amorphous solids is due to the accumulation of elementary events, consisting of spatially and temporally localized atomic rearrangements involving only a few tens of atoms. Recently, numerical and experimental work addressed the issue of spatiotemporal correlations between these plastic events. Here, we provide further insight into these correlations by investigating, via molecular dynamics (MD) simulations, the plastic response of a two-dimensional amorphous solid to artificially triggered local shear transformations. We show that while the plastic response is virtually absent in as-quenched configurations, it becomes apparent if a shear strain was previously imposed on the system. Plastic response has a fourfold symmetry, which is characteristic of the shear stress redistribution following the local transformation. At high shear rate we report evidence for a fluctuation-dissipation relation, connecting plastic response and correlation, which seems to break down if lower shear rates are considered.

Nucleation in hydrophobic cylindrical pores: a lattice model.

We consider the nucleation process associated with capillary condensation of a vapor in a hydrophobic cylindrical pore (capillary evaporation). The liquid-vapor transition is described within the framework of a simple lattice model. The phase properties are characterized both at the mean-field level and with Monte Carlo simulations. The nucleation process for the liquid to vapor transition is then specifically considered. Using umbrella sampling techniques, we show that nucleation occurs through the condensation of an asymmetric vapor bubble at the pore surface. Even for highly confined systems, good agreement is found with macroscopic considerations based on classical nucleation theory. The results are discussed in the context of recent experimental work on the extrusion of water in hydrophobic pores.

Measurement of plasma human chorionic gonadotropin (hCG) and beta-hCG activities in the late luteal phase: evidence of the occurrence of spontaneous menstrual abortions in infertile women.

Plasma luteinizing hormone (LH-human chorionic gonadotropin (hCG) and beta-hCG activities were measured during the late luteal phase in 321 cycles of 147 infertile women. In 71 cycles the hCG measurement permitted the diagnosis of pregnancy between the 10th and 14th days after the thermal nadir. The slope of the regression line derived from hCG levels during the first 22 days of pregnancy was significantly lower in pregnancies which aborted before the 60th day than in normal pregnancies (P less than 0.01). Among 72 cycles ended by apparently normal menses which exhibited an LH-hCG activity at least equal to 7 mIU of hCG/ml during the late luteal phase, the beta-hCG activity was measured in 49 cycles during which hCG had not been given. Significant beta-hCG activity (greater than or equal to 4 mIU of hCG/ml) was detected in 19 cases. This finding supports the assumption that secretory trophoblastic tissue had been present and that spontaneous menstrual abortions had occurred in these women.