The effect of felled tree stems as bio-engineering type rockfall protection

International audienceIn mountainous regions forested slopes play an important protective role against rockfall. Up to now, most of the researches on rockfall protection forest have been and are focused on the dissipative effect of standing and living trees. There are hardly any studies on the protective capacity of tree stumps and lying stems against snow avalanches and rockfalls. Although, these techniques are more and more used throughout the Alps. In Austria, the felling technique Alpi has been developed, which allows a specialised lumberjack to create small rockfall barriers using one or two tree stems anchored on high tree stumps. Lying tree stems can be then used to increase efficiently the roughness of the soil and so to limit or avoid triggering and propagation falling rocks. But, due to the wood decay, the efficiency of such bio-engineering type protective works is decreasing with time. One of the questions that the forest and natural hazard managers have to answer is: what is the lifetime of such protective structures? In order to answer to this question we have developed a specific research on this thematic. The main objectives of this research program are to quantify the efficacy of these bio-engineering type rockfall fences depending on their characteristics (stump and stems density, position on the slope, tree species, etc.), and to evaluate their resistance over time. To achieve these objectives we have developed two types of experiments. The first one, performed during the summer 2009 on our experimental site test of Vaujany (France), are full scale rockfall experiments on four felled trees, which have been anchored on their stumps and are lying in an oblique direction to the slope. In total, fifty rocks (from 522 at 2242 kg) have been released one by one. For each rock, the trajectory has been filmed with high speed digital cameras. The second type of experiment is the uprooting of tree stumps (spruce, fir and beech) of different ages and diameter. To uproot the stumps we are using the same technique as for winching tests. For each experiment, stumps samples are taken in order to determine the wood decay ratio. Finally, a statistical analysis will be made in order to study the correlation between the force required to uproot a stump and its wood decay ratio. The first uprooting test campaign has been held during the summer 2009. First results of both experiment types will be presented. This study is part of the European Interreg IV Alpine Space project "MANFRED"

Reactive imbibition of WC-Co substrate for PDC cutters used in oil and gas and mining drilling

International audienceCemented carbides are used in rock drilling for mining tools and wear resistant parts. These composite materials possess an excellent compromise between hardness and toughness. Nowadays, the concept of graded structure is widely studied to improve these two properties simultaneously, and so to increase the service life of drilling tools. A continuous composition gradient on several millimetres is generated in commercial WC-Co substrate for PDC cutters by using Reactive Imbibition method. The effects of this process are analysed in terms of microhardness, cobalt concentration and WC grain size. A continuous gradient of about 300HV on 8mm-height substrate is obtained in one-step by imbibition process into combination with a boron-rich coating deposed on its free surface. In part, this gradient of hardness and its shape are preserved after HPHT (high pressure-high temperature) process that is used for the diamond table deposition on the WC-Co substrate. Such gradient must significantly increase the cutter service life

Intricate visibility effects from resolved emission of young stellar objects: the case of MWC158 observed with the VLTI

In the course of our VLTI young stellar object PIONIER imaging program, we have identified a strong visibility chromatic dependency that appeared in certain sources. This effect, rising value of visibilities with decreasing wavelengths over one base, is also present in previous published and archival AMBER data. For Herbig AeBe stars, the H band is generally located at the transition between the star and the disk predominance in flux for Herbig AeBe stars. We believe that this phenomenon is responsible for the visibility rise effect. We present a method to correct the visibilities from this effect in order to allow "gray" image reconstruction software, like Mira, to be used. In parallel we probe the interest of carrying an image reconstruction in each spectral channel and then combine them to obtain the final broadband one. As an illustration we apply these imaging methods to MWC158, a (possibly Herbig) B[e] star intensively observed with PIONIER. Finally, we compare our result with a parametric model fitted onto the data.Comment: 14 pages, 7 figure

A Dose-Response Study of a Live Attenuated Varicella-Zoster Virus (Oka Strain) Vaccine Administered to Adults 55 Years of Age and Older

Decreased cell-mediated immune (CMI) response to varicella-zoster virus (VZV) is correlated with an increased risk of reactivation of latent virus from dorsal root sites, leading to herpes zoster. The cell-mediated and humoral immunogenicity of three concentrations (3200, 8500, and 41,650 pfu/dose) of a live attenuated VZV vaccine (Oka strain; VZV/Oka) was compared with a control pneumococcal polysaccharide vaccine in 200 healthy adults who were ≥55 years old. Six weeks after vaccination, the VZV-specific CMI response (as measured by stimulation index values and precursor cell frequencies) was enhanced in all VZV/Oka vaccine groups compared with the control group (for all VZV/Oka groups combined vs. controls, tested with VZV crude antigen: stimulation index, P < .001; precursor cell frequency, P < .001). Geometric mean titers of anti-VZV antibodies increased in all VZV/Oka vaccine groups but remained unchanged in the control vaccine group. No dose effect of VZV/Oka vaccine was observed for CMI or humoral response

A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

Recently, Lund and Iyer (L&amp;I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&amp;I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&amp;I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based

Lessons Learned: The Multifaceted Field of (Digital) Neighborhood Development

In a cross-national project, 14 neighborhoods from Germany, Austria and Switzerland were accompanied on their way to digitally supported neighborhood work. This paper discusses general requirements, choosing a suitable digital tool, the implementation process as well as the challenges faced by the various stakeholders. The following factors have been found to play a major role in sustainable neighborhood work: good fit with overall development strategy, interplay between online neighborhood work and physical interactions, strong existing neighborhood management structures, strategic planning of digitalization activities, start-up funding for innovation activities, and above all, the presence of a committed person or team as well as interesting content to attract users. Depending on the neighborhood, self-managed and individualistic solutions are preferred to generic and/or commercial solutions. There is no ‘fit-for-all’ path to sustainable digitally supported neighborhoods