Time-variable 3D ground displacements from High-Resolution Synthetic Aperture Radar (SAR). Application to La Valette landslide (South French Alps).

International audienceWe apply an image correlation technique to multi-orbit and multi-temporal High-Resolution (HR) SAR data. Image correlation technique has the advantage of providing displacement maps in two directions; e.g. the Line of Sight direction (LoS) and the Azimuth direction. This information, derived from the two modes of data acquisition (ascending and descending), can be combined routinely to infer the three dimensional surface displacement field at different epochs. In this study, a methodology is developed to characterize the displacement pattern of the large La Valette landslide (South French Alps) using TerraSAR-X images acquired in 2010. The results allow mapping the dynamics of different units of the La Valette landslide at high spatial resolution. The study demonstrates the potential of this new application of High Resolution SAR image correlation technique for landslide ground surface deformation monitoring

Seismic and aseismic deformation along the East African Rift System from a reanalysis of the GPS velocity field of Africa

International audienceThe improvement of the geodetic coverage within the African Plate over the last decade together with an extended GPS position time-series allows improved accuracy in determining the velocity field than prior geodetic studies. Using this new velocity field of the whole African continent, the best model proposed here remains consistent with previous studies including the existence of two small plates along the East African Rift System (EARS, Victoria and Rovuma).We focus specifically on the velocities along this plate boundary by estimating both the geodetic and the seismic moment rate.Whereas we use a scalar form of the Kostrov relation to calculate the geodetic moment rate, the seismic moment rate is obtained by integrating the cumulative truncated Gutenberg-Richter earthquake distribution of local events in the 39-yr-long worldwide catalogue, using a maximum likelihood method. This statistical method allows us to take into account the probable incompleteness of the existing catalogue and to assume the seismic moment rate calculated from this short catalogue to be representative of the long-term seismic deformation. The comparison of geodetic and seismic energy release sheds light on the variations of mechanical behaviour related to intracontinental extension along the EARS. The southward increase, observed along the rift, of the proportion of geodetic moment seismically accommodated suggests a significant control of the thermal structure associated with different states of rifting evolution

Numerical and experimental study of inertia-gravity waves in the differentially heated rotating annulus

International audienceThe occurrence and source mechanism of inertia-gravity waves (IGWs) are studied in the differentially heated rotating annulus via laboratory experiments (BTU) and numerical simulations (GUF). Two differentially heated rotating annulus experiments are used for this purpose at the BTU laboratories. The first is a modified version of the classical baroclinic experiment in which a juxtaposition of convective and motionless stratified layers can be created by introducing a vertical salt stratification. The thermal convective motions are suppressed in a central region at mid depth of the rotating tank, therefore baroclinic waves can only build up in thin layers located at the top and bottom, where the salt stratification is weakest. This new experimental setup, coined "barostrat instabil-ity", allows to study the exchange of momentum and energy between the layers, especially by the propagation of IGWs. Moreover, in contrast to the classical tank without salt stratification we have layers with N/f > 1. A ratio larger than unity implies that the IGW propagation in the experiment is expected to be qualitatively similar to the atmospheric case. Interestingly, we found local IGW packets along the jets in the surface and bottom layers where the local Rossby number is larger than 1, suggesting spontaneous imbalance as generating mechanism [1], and not boundary layer instability [2]. Theoretical considerations and numerical simulations have led to the identification of an annulus configuration, much wider and shallower, with a much larger temperature difference between the inner and outer cylinder walls, which is more atmosphere-like since it shows an N / f >1 even without the vertical salt stratification. Flow regime stability has been tested for this new differentially heated rotating annulus and compared with findings from the small tank. In view of the different geometries of the two experimental systems, their correspondence was excellent with respect to the large-scale. Moreover, direct numerical simulations were performed (GUF) for this atmosphere-like configuration of the experiment and possible regions of IGW activity were characterised by a Hilbert-transform algorithm. The simulations show a clear baroclinic wave structure exhibiting a realistic jet-front system superimposed by small-scale structures which are associated with IGWs occurring in wave packets [3]. The comparison of observations from a corresponding big tank experiment with numerical simulation shows that for both cases (as we already observed in the barostrat experiment), small scale wave packets are clearly correlated with an increased local Rossby number

Local and global hydrological contributions to gravity variations observed in Strasbourg

International audienceWe investigate the contribution of local and global hydrology to the superconducting gravimeter (SG) installed in the Strasbourg observatory.Adeterministic approach is presented to account for the contribution of water storage variations in the soils in the vicinity of the gravimeter: both amount and distribution of water masses are determined before calculating Newtonian attraction. No adjustment is performed on gravity time series. Two multi-depth Frequency Domain Reflectometer (FDR) probes have been installed to monitor the amount of water stored in the soil layer above the gravimeter. Since August 2005, they have been monitoring the variation of the water content of the entire soil thickness. Several investigations have been undertaken in order to estimate the distribution of water masses: a precise local DEM (Digital Elevation Model) has been determined using differential GPS. The geometry and heterogeneity of the soil layer have been evaluated thanks to geophysical and geomechanical prospections. The comparison between observed and modelled gravity variations shows that daily up to seasonal variations are in good agreement. For long-term variations, deep water storage and other processes have to be modelled to explain recorded gravity variations

The structure of the antimicrobial human cathelicidin LL-37 shows oligomerization and channel formation in the presence of membrane mimics

The human cathelicidin LL-37 serves a critical role in the innate immune system defending bacterial infections. LL-37 can interact with molecules of the cell wall and perforate cytoplasmic membranes resulting in bacterial cell death. To test the interactions of LL-37 and bacterial cell wall components we crystallized LL-37 in the presence of detergents and obtained the structure of a narrow tetrameric channel with a strongly charged core. The formation of a tetramer was further studied by cross-linking in the presence of detergents and lipids. Using planar lipid membranes a small but defined conductivity of this channel could be demonstrated. Molecular dynamic simulations underline the stability of this channel in membranes and demonstrate pathways for the passage of water molecules. Time lapse studies of E. coli cells treated with LL-37 show membrane discontinuities in the outer membrane followed by cell wall damage and cell death. Collectively, our results open a venue to the understanding of a novel AMP killing mechanism and allows the rational design of LL-37 derivatives with enhanced bactericidal activity

Inventory of the potato diseases and impact on growth and yield traits in far North Cameroon

Potato (Solanum tuberosum L) production in the Far North Region of Cameroon is faced with scarcity or inequality of rains and with diseases that affect yields. To improve the production a study was conducted in the production area of Mogode subdivision with the objective of identifying potato diseases and pathogens agents. The experimental design was in complete randomized blocks. The plant material used was a local variety of potato (Dosa). Diseases and pathogens have been identified on a base of symptoms and morphological characteristics. The incidence, severity and rainfall were assessed. Yield, number of stems and diameter of the tubers were evaluated. The diseases identified are fungal (late blight, Alternaria or early blight and Fusarium wilt), viral (Virosis M, Rust stain and Potato leaf roll (PLR) and bacterial (Bacterial wilt and Common scab). Conidia of Phytophthora infestans, and Alternaria spp. were found.Whatever the site and disease, the incidence has remained below 25%. Late blight was more present in the Gouria site, Alternaria and virosis M more present in the Mouvou site. The yield was roughly the same at the two sites, around 3 t/ha. The highest number of stems was obtained at Gouria, 18 ± 0.75. The potato is attacked by several diseases. The results of this study represent an important baseline data for the implementation of integrated disease management in Cameroon.Keywords: Solanum tuberosum, diseases, pathogens, incidence, severity, yield

Estimation of sex and age of "virtual skeletons”-a feasibility study

This article presents a feasibility study with the objective of investigating the potential of multi-detector computed tomography (MDCT) to estimate the bone age and sex of deceased persons. To obtain virtual skeletons, the bodies of 22 deceased persons with known age at death were scanned by MDCT using a special protocol that consisted of high-resolution imaging of the skull, shoulder girdle (including the upper half of the humeri), the symphysis pubis and the upper halves of the femora. Bone and soft-tissue reconstructions were performed in two and three dimensions. The resulting data were investigated by three anthropologists with different professional experience. Sex was determined by investigating three-dimensional models of the skull and pelvis. As a basic orientation for the age estimation, the complex method according to Nemeskéri and co-workers was applied. The final estimation was effected using additional parameters like the state of dentition, degeneration of the spine, etc., which where chosen individually by the three observers according to their experience. The results of the study show that the estimation of sex and age is possible by the use of MDCT. Virtual skeletons present an ideal collection for anthropological studies, because they are obtained in a non-invasive way and can be investigated ad infinitu

Optimization and uncertainty quantification of gradient index metasurfaces

The design of intrinsically flat two-dimensional optical components, i.e., metasurfaces, generally requires an extensive parameter search to target the appropriate scattering properties of their constituting building blocks. Such design methodologies neglect important near-field interaction effects, playing an essential role in limiting the device performance. Optimization of transmission, phase-addressing and broadband performances of metasurfaces require new numerical tools. Additionally, uncertainties and systematic fabrication errors should be analysed. These estimations, of critical importance in the case of large production of metaoptics components, are useful to further project their deployment in industrial applications. Here, we report on a computational methodology to optimize metasurface designs. We complement this computational methodology by quantifying the impact of fabrication uncertainties on the experimentally characterized components. This analysis provides general perspectives on the overall metaoptics performances, giving an idea of the expected average behavior of a large number of devices

Masitinib Combined with Standard Gemcitabine Chemotherapy: In Vitro and In Vivo Studies in Human Pancreatic Tumour Cell Lines and Ectopic Mouse Model

International audienceBackground: Tyrosine kinases are attractive targets for pancreatic cancer therapy because several are over-expressed, including PDGFRα/β, FAK, Src and Lyn. A critical role of mast cells in the development of pancreatic cancer has also been reported. Masitinib is a tyrosine kinase inhibitor that selectively targets c-Kit, PDGFRα/β, Lyn, and to a lesser extent the FAK pathway, without inhibiting kinases of known toxicities. Masitinib is particularly efficient in controlling the proliferation, differentiation and degranulation of mast cells. This study evaluates the therapeutic potential of masitinib in pancreatic cancer, as a single agent and in combination with gemcitabine.Methodology/Findings: Proof-of-concept studies were performed in vitro on human pancreatic tumour cell lines and then in vivo using a mouse model of human pancreatic cancer. Molecular mechanisms were investigated via gene expression profiling. Masitinib as a single agent had no significant antiproliferative activity while the masitinib/gemcitabine combination showed synergy in vitro on proliferation of gemcitabine-refractory cell lines Mia Paca2 and Panc1, and to a lesser extent in vivo on Mia Paca2 cell tumour growth. Specifically, masitinib at 10 µM strongly sensitised Mia Paca2 cells to gemcitabine (>400-fold reduction in IC50); and moderately sensitised Panc1 cells (10-fold reduction). Transcriptional analysis identified the Wnt/β-catenin signalling pathway as down-regulated in the cell lines resensitised by the masitinib/gemcitabine combination.Conclusions: These data establish proof-of-concept that masitinib can sensitise gemcitabine-refractory pancreatic cancer cell lines and warrant further in vivo investigation. Indeed, such an effect has been recently observed in a phase 2 clinical study of patients with pancreatic cancer who received a masitinib/gemcitabine combination

Concurrent Bounded Model Checking

The Definitive Version can be found in the ACM Digital Library here: http://dx.doi.org/10.1145/2693208.2693240issue_date: January 2015 numpages: 5 acmid: 2693240 keywords: Bounded Model Checking, Concurrency, Symbolic Executionissue_date: January 2015 numpages: 5 acmid: 2693240 keywords: Bounded Model Checking, Concurrency, Symbolic Executionissue_date: January 2015 numpages: 5 acmid: 2693240 keywords: Bounded Model Checking, Concurrency, Symbolic Executio