Impact of treated wastewater irrigation on antibiotic resistance in agricultural soils

Antibiotic resistance (AR) is a global phenomenon with severe epidemiological ramifications. Anthropogenically impacted natural aquatic and terrestrial environments can serve as reservoirs of antibiotic resistance genes (ARG), which can be horizontally transferred to human-associated bacteria through water and food webs, and thus contribute to AR proliferation. Treated-wastewater (TWW) irrigation is becoming increasingly prevalent in arid regions of the world, due to growing demand and decline in freshwater supplies. The release of residual antibiotic compounds, AR bacteria, and ARGs from wastewater effluent may result in proliferation of AR in irrigated soil microcosms. The aim of this study was to assess the impact of TWW-irrigation on soil AR bacterial and ARG reservoirs. Tetracycline, erythromycin, sulfonamide, and ciprofloxacin resistance in soil was assessed using standard culture-based isolation methods and culture-independent molecular analysis using quantitative real-time PCR (qPCR). High levels of bacterial antibiotic resistance were detected in both freshwater- and TWW-irrigated soils. Nonetheless, in most of the soils analyzed, AR bacteria and ARG levels in TWW-irrigated soils were on the whole identical (or sometimes even lower) than in the freshwater-irrigated soils, indicating that the high number of resistant bacteria that enter the soils from the TWW are not able to compete or survive in the soil environment and that they do not significantly contribute ARG to soil bacteria. This strongly suggests that the impact of the TWW-associated bacteria on the soil microbiome is on the whole negligible, and that the high levels of AR bacteria and ARGs in both the freshwater- and the TWW-irrigated soils are indicative of native AR associated with the natural soil microbiome.     

Electrodeposition of metallic molybdenum and its alloys – a review

Aqueous electrodeposition may represent a more economical and reliable technique to fabricate Mo coatings than the alternatives (electrodeposition from fused-salt baths and other available methods). However, studies on the aqueous electrodeposition of pure metallic Mo are rather limited due to its oxophilic nature, catalytic behaviour for the hydrogen evolution reaction and high tendency for polymerisation, especially in acidic media. To date, researchers have tended to focus on the aqueous electrodeposition of Mo alloys. These alloys usually contain <51% Mo. The factors that influence the quality of Mo deposits and the difficulties in the electrodeposition process are reviewed here. This review not only presents a survey of existing literature on the electrodeposition of metallic Mo coatings but also provides a basis for any future exploration.     

Body tilt effect on the reproduction of orientations: Studies on the visual oblique effect and subjective orientations.

Body tilt effects on the visual reproduction of orientations and the Class 2 oblique effect (E. A. Essock, 1980) were examined. Body tilts indicate whether the oblique effect (i.e., lower performance in oblique orientations than in vertical-horizontal orientations) is defined in an egocentric or a gravitational reference frame. Results showed that the oblique effect observed in upright posture disappeared in tilted conditions, mainly due to a decrease in the precision of the vertical and horizontal settings. In tilted conditions, the subjective visual vertical proved to be the orientation reproduced the most precisely. Thus, the oblique effect seemed to be not purely gravitationally or egocentrically defined but, rather, to depend on a subjective gravitational reference frame tilted in the same direction as body tilts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Méthodes de simulation des circuits analogiques non linéaires microondes

This paper presents the non linear microwave circuits simulation methods presently in use. First, the timedomain analysis method is presented, the principal advantage of which is to allow transient states study. The second method, based on harmonic balance principle, allows to obtain quickly the steady state regime. The third part extends Fourier’s transform techniques to a quasi periodic signals. At last, a noise analysis method of non-linear circuits, based on conversion matrices and noisy sources correlation matrices is proposed.     

Understanding complex systems

A system or a model is called complex when it contains such a great number of interconnected variables or elements that it is generally no longer possible to understand its global working without using simplified or condensed forms of the model. With respect to the assumed complexity of a system, simplified models often give rise to some inconsistency and there is a need for guides, or procedures, for a whole understanding of complex interdependent systems which do not imply any loss of information. The proposed approach can also be seen as an extension of the so-called interpretive structural modeling techniques to models embedding many feedbacks between their elements. Briefly summarized, it consists of bringing into focus some particular minimum sets of variables such that, if the variables of one of these sets were fixed by some control, the model would contain no feedbacks. Consequently, it is then possible to define a hierarchical order of the variables of an interdependent system, which is analogous to the hierarchical order given by the reduced graph of a recursive system. An operational computer algorithm is proposed which has been successfully tested with several economic models, some of which contain more than 10 000 circuits.     

Restoration ecology studies at Cazarils (southern France): Biodiversity and ecosystem trajectories in a mediterranean landscape

Restoration ecology (RE) offers a conceptual meeting ground and methodological approaches for all those concerned with the past, present and future of ecosystems and landscapes. It combines ecological theory, nature conservation concerns and recognition of the need to develop new management tools for ecosystems and landscapes. In our approach, ‘vital ecosystem attributes' (VEAs) of ecosystems and landscapes are monitored along transects permitting detailed assessment of the impact of economic and RE interventions at the scale of whole landscapes. This also enables quantitative and qualitative comparisons among ecosystems and/or among landscapes. At a new long-term ecological research site (LTER) at Cazarils, southern France, we are studying ecosystem and landscape responses to past and present human uses and perturbations, and to contemporaneous interventions aimed at restoration, rehabilitation and landscape reintegration. In this paper, we present selected baseline data of landscape-wide ranges concerning several different VEAs of both above- and below-ground components of biodiversity as well as soils. The purpose is to describe an approach to landscape research planning and ecosystem management in areas with complex geomorphological, ecological and cultural–historical features such as the Mediterranean region, and surrounding arid or semiarid lands.     

FM-to-AM conversion in high-power lasers

FM-to-AM conversion is an important issue that could prevent fusion ignition with high-power lasers, such as the Laser MegaJoule (LMJ). We first overview the whole problem of FM-to-AM conversion in high-power lasers and we explain why AM spectral content of FM-to-AM conversion is important, although this information was not used in previous studies. We then propose simple analytical models to simulate FM-to-AM conversion in the LMJ frequency conversion system. We succeed in isolating every cause of spectrum distortion and give, for each of them, FM-to-AM predictions that are in very good agreement with simulations of a complex propagation code. Finally, we show how the last grating filters most of the FM-to-AM conversion. We conclude that the FM-to-AM conversion distortion criterion will be, on LMJ, below 40% in the last optics and 10% on the target.     

Fatigue behavior of a multi-scale cement composite

To conceive structural elements with a cement composite and without any reinforcement except steel fibers is a very exciting and difficult challenge, which can change the building construction fields. To achieve this objective the Laboratoire Central des Ponts et Chaussées (LCPC) has developed a new cement composite, CEMTEC_multiscale®, which is strain hardening in tension and has a very high uniaxial tensile strength, more than 20 MPa.The present paper is on an experimental research related to this composite fatigue behavior. The principal results obtained are the following:

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A strong correlation exists between the initial static damage and the fatigue endurance limit.

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Below a loading ratio R = 0.65 (ratio between the applied stress and the characteristic static stress), failure during bending fatigue tests never appears with CEMTEC_multiscale® specimen.

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An 8% gain is observed between the bending static behavior of the specimens being previously loaded in fatigue and those not being loaded in fatigue.