High plasmatic progesterone levels at insemination depress reproductive performances of rabbit does

The aim of this experiment was to quantify the frequency of the high progesterone syndrome at the moment of insemination and to study the influence of progesterone level (P4) on receptivity and reproductive performances of primiparous and secondiparous rabbit does. A total of 422 primiparous INRA 0067 were inseminated twice at an interval of 42 days. Prior to artificial insemination (AI), sexual receptivity of the does was tested in the presence of a vasectomised buck and, just after AI, blood samples were collected to determine progesterone concentration by RIA. The mean plasma progesterone concentration was 1.8\ub13.4 ng/ml and significantly depended on parity (primiparous: 2.2\ub13.7 ng/ml, secondiparous: 0.9\ub12.2 ng/ml, P<0.001). At the following AI, 78% of pseudopregnant rabbit does returned to the basal level of oestrous condition, demonstrating that the pseudopregnancy is a reversible process. The overall percentage of pseudopregnant does (P4 651 ng/ml) was 25.9%, but it was differently (P<0.001) distributed between primiparous (31.2%) and secondiparous does (12.2%). Moreover, primiparous lactating females were more frequently pseudopregnant than non-lactating ones (36.5 vs. 18.9% respectively, P<0.001). The progesterone level of primiparous does was related to the lactation status (2.5\ub13.8 vs. 1.5\ub13.2 ng/ml, respectively for lactating and non-lactating, P<0.001). The receptivity was highly related to the level of progesterone (P4<1: 74.1%, 1 64P4<6: 79.1% vs. P4>6: 56.3%, P=0.006). Also the kindling rate was significantly influenced by progesterone concentrations. Non-pseudopregnant does (P<1 ng/ml) had the highest fertility rate (79.0%) but when the progesterone concentration increased from 1 64P4<6 to P4>6 ng/ml, the fertility decreased from 68.1 to 37.4%, respectively (P<0.001). Consequently, the productivity at birth was highly depressed when the progesterone level was over 6 ng/ml (9.5 and 8.6 vs. 4.5 number of born alive rabbits/AI, for P4<1, 1 64P4<6 and P4>6 respectively, P<0.001). The productivity of pseudopregnant and nonreceptive females was very poor in comparison with pseudopregnant receptive does (0.4 vs. 9.5 born alive rabbits/AI). The productivity at birth was also highly (P<0.001) influenced by the physiological status of the does. Primiparous non-lactating does produced the highest number of born alive rabbits/AI, whereas primiparous lactating does had the lowest productivity at birth (9.9 vs. 5.6), secondiparous lactating being intermediate (7.1). In conclusion, the high progesterone syndrome evaluated at the moment of insemination occurred in 25.9% of females and had a strong negative impact on receptivity and reproductive performance of rabbit does

Évolution récente du delta de la Yamachiche (Québec) : processus naturels et impacts anthropiques

Le lac Saint-Pierre, un élargissement du fleuve Saint-Laurent, pourrait connaître une baisse importante de niveau d’eau dans les cinquante prochaines années, conséquence du réchauffement climatique global. Sept rivières débouchent dans ce lac fluvial peu profond qui risquerait d’enregistrer une sédimentation importante. Nous avons étudié le delta de l’un de ces tributaires, la Yamachiche, pour évaluer les processus de sédimentation et les réponses de la rivière aux changements environnementaux passés. L’évolution du delta de la Yamachiche a été reconstituée par des photographies aériennes, des cartes anciennes, des analyses sédimentologiques et stratigraphiques de six coupes et de quatorze forages, et la datation par luminescence optique, 210Pb et 14C. Le delta est caractérisé par deux types de dépôts. La base est constituée de dépôts sableux de lit mineur du chenal, mis en place dans des conditions de sédimentation et d’érosion fréquentes. Ils sont surmontés par des dépôts limoneux de plaine d’inondation deltaïque, comprenant des lits sableux locaux. Ces dépôts présentent une variabilité latérale et longitudinale expliquée par les variations de niveau d’eau du lac et de la rivière à une échelle annuelle et décennale, par les migrations du chenal et par l’action érosive des vagues du lac Saint-Pierre. Le delta s’est formé depuis 150 ans, comme le montre la carte de 1859 où le delta n’était que très peu développé. La luminescence optique attribue des âges de 140 et de 280 ans aux dépôts sableux à la base. Les datations révèlent des taux d’accumulation verticale moyens compris entre 0,5 et 1,5 cm/an. Cette accumulation importante serait liée aux perturbations anthropiques affectant les sources sédimentaires du bassin versant depuis le début de la colonisation il y a 200 ans. L’âge récent du delta serait également expliqué par la stabilisation tardive du lac Saint-Pierre à son niveau actuel, qui est intervenue entre 1000 et 150 ans.Lake St. Pierre, being an enlargement of the St. Lawrence River, could experience a significant base level drop in the next fifty years as a consequence of global climate warming. Seven tributaries flow into this shallow lake, and base level changes could lead to increased sedimentation rates. We have studied the delta of the Yamachiche River, a tributary of Lake St. Pierre. The objective of the study is to document the active geomorphic processes and the response of the river to past environmental changes. We have reconstructed the evolution of the Yamachiche delta from aerial photos, historical maps, sedimentological and stratigraphic analysis of six sections and fourteen boreholes, and by sediment dating using optically stimulated luminescence, 210Pb and 14C. The subsurface deposits are divided into two facies : sandy low-water channel deposits at the base, and silty delta plain deposits at the top. Sedimentary sequences show changes along a longitudinal gradient driven by the level of the lake and the river dynamics on annual and decadal scales, and a high lateral variability driven by migration of the channel and by high-energy waves from Lake St. Pierre, which erode the downstream eastern part of the delta plain. Rapid progradation of the delta has occurred in the last 150 years, as demonstrated by the poor development of the delta on the 1859 map. Optically stimulated luminescence dating provides ages of 140 and 280 years at the base of the depositional sequence. These results are consistent with the chronological sequence deduced from the other dating methods. This framework gives mean accumulation rates between 0.5 and 1.5 cm/year. These high rates of sedimentation are likely linked to human activities in the watershed, which affected sedimentary sources since colonization of the St. Lawrence Lowlands 200 years ago. The young age of the delta could also be explained by the late stabilization of Lake St. Pierre at its present level, between 1000 and 150 years ago

Luminosity indicators in dusty photoionized environments

The luminosity of the central source in ionizing radiation is an essential parameter in a photoionized environment, and one of the most fundamental physical quantities one can measure. We outline a method of determining luminosity for any emission-line region using only infrared data. In dusty environments, grains compete with hydrogen in absorbing continuum radiation. Grains produce infrared emission, and hydrogen produces recombination lines. We have computed a very large variety of photoionization models, using ranges of abundances, grain mixtures, ionizing continua, densities, and ionization parameters. The conditions were appropriate for such diverse objects as H II regions, planetary nebulae, starburst galaxies, and the narrow and broad line regions of active nuclei. The ratio of the total thermal grain emission relative to H$\beta$ (IR/H$\beta$) is the primary indicator of whether the cloud behaves as a classical Str\"{o}mgren sphere (a hydrogen-bounded nebula) or whether grains absorb most of the incident continuum (a dust-bounded nebula). We find two global limits: when $IR/H\beta<100$ infrared recombination lines determine the source luminosity in ionizing photons; when $IR/H\beta\gg100$ the grains act as a bolometer to measure the luminosity.Comment: 12 pages 3 figures. Accepted ASP Sept.9

The effects of the complete replacement of barley and soybean meal with hard wheat by-products on diet digestibility, growth and slaughter traits of a local Algerian rabbit population

[EN] Eighty one rabbits were used to study the utilisation of hard wheat by-products on the growth of rabbits from a local Algerian population. At weaning (28 d, 501±99 g), the animals were individually caged and received ad libitum one of the three experimental diets for 49 d. The control diet included 26% wheat bran (W26: control diet), alfalfa, bar- ley and soybean meal. The two other diets were formulated by substituting barley and soybean meal with hard wheat by-products, and contained 60% (W60) or 67% (W67) of these by-products (50 or 57% bran and 10% middling). On average, diets contained 11.8% crude fibre and crude protein decreased from 18.3 (W26) to 16.1% (W67). Growth traits and slaughter performances were recorded. Another group of thirty animals was used to determine dietary nutrient di- gestibility from 42 to 46 d of age. Dry matter digestibility and digestible energy content were lower in the W60 and W67 diets than in the control diet (W26) (71.3 and 71.5% vs. 74.9%, and 11.9 and 11.9 vs. 12.5 MJ/kg, respectively; P<0.01). In contrast, crude fibre digestibility was lower in W26 (21.9%) than in the other two diets (29.6 and 32.2% for W60 and W67, respectively; P<0.01). The growth rates were similar for all three groups (28.0, 27.1 and 26.0 g/d for W26, W60 and W67) as were the feed conversion ratios (3.14, 3.17 and 3.10, respectively). Dressing out percentage (66.4±2.0% on average for the cold carcass) was not affected by the amount of wheat by-products in the diet. The total mortality rate was high (23%), probably corresponding to the low crude fibre content of the three experimental diets, but was not connected to the amount of wheat by-products.Lakabi-Ioualitene, D.; Lounaouci-Ouyed, G.; Berchiche, M.; Lebas, F.; Fortun-Lamothe, L. (2010). The effects of the complete replacement of barley and soybean meal with hard wheat by-products on diet digestibility, growth and slaughter traits of a local Algerian rabbit population. World Rabbit Science. 16(2). doi:10.4995/wrs.2008.63216

Stealth Acoustic Materials

[EN] We report the experimental design of a one-dimensional stealth acoustic material, namely a material that suppresses the acoustic scattering for a given set of incident wave vectors. The material consists of multiple scatterers, rigid diaphragms, located in an air-filled acoustic waveguide. The position of the scatterers has been chosen such that in the Born approximation a suppression of the scattering for a broad range of frequencies is achieved and thus a broadband transparency. Experimental results are found in excellent agreement with the theory despite the presence of losses and the finite size of the material, features that are not captured in the theory. This robustness as well as the generality of the results motivates realistic potential applications for the design of transparent materials in acoustics and other fields of wave physics.This work has been funded by RFI Le Mans Acoustique (Region Pays de la Loire) in the framework of the APA-MAS project, by the project HYPERMETA funded under the program Etoiles Montantes of the Region Pays de la Loire as well as by the Ministerio de Economia y Competitividad (Spain) and European Union FEDER through project FIS2015-65998-C2-2-P. V. Romero-Garcia and L. M. Garcia-Raffi acknowledge the short-term scientific mission (STSM) funded by the COST (European Cooperation in Science and Technology) Action DENORMS - CA15125.Romero-García, V.; Lamothe, N.; Theocharis, G.; Richoux, O.; García-Raffi, LM. (2019). Stealth Acoustic Materials. Physical Review Applied. 11(5):1-9. https://doi.org/10.1103/PhysRevApplied.11.054076S19115Shen, C., Xu, J., Fang, N. X., & Jing, Y. (2014). 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Physical Review B, 75(1). doi:10.1103/physrevb.75.014304Khelif, A., Wilm, M., Laude, V., Ballandras, S., & Djafari-Rouhani, B. (2004). Guided elastic waves along a rod defect of a two-dimensional phononic crystal. Physical Review E, 69(6). doi:10.1103/physreve.69.067601Sigalas, M. M. (1998). Defect states of acoustic waves in a two-dimensional lattice of solid cylinders. Journal of Applied Physics, 84(6), 3026-3030. doi:10.1063/1.368456Khelif, A., Choujaa, A., Djafari-Rouhani, B., Wilm, M., Ballandras, S., & Laude, V. (2003). Trapping and guiding of acoustic waves by defect modes in a full-band-gap ultrasonic crystal. Physical Review B, 68(21). doi:10.1103/physrevb.68.214301Romero-García, V., Sánchez-Pérez, J. V., Castiñeira-Ibáñez, S., & Garcia-Raffi, L. M. (2010). Evidences of evanescent Bloch waves in phononic crystals. Applied Physics Letters, 96(12), 124102. doi:10.1063/1.3367739Baba, T. (2008). Slow light in photonic crystals. Nature Photonics, 2(8), 465-473. doi:10.1038/nphoton.2008.146Kaya, O. A., Cicek, A., & Ulug, B. (2012). Self-collimated slow sound in sonic crystals. Journal of Physics D: Applied Physics, 45(36), 365101. doi:10.1088/0022-3727/45/36/365101Theocharis, G., Richoux, O., García, V. R., Merkel, A., & Tournat, V. (2014). Limits of slow sound propagation and transparency in lossy, locally resonant periodic structures. New Journal of Physics, 16(9), 093017. doi:10.1088/1367-2630/16/9/093017Groby, J.-P., Pommier, R., & Aurégan, Y. (2016). Use of slow sound to design perfect and broadband passive sound absorbing materials. The Journal of the Acoustical Society of America, 139(4), 1660-1671. doi:10.1121/1.4945101Wiersma, D. S. (2013). Disordered photonics. Nature Photonics, 7(3), 188-196. doi:10.1038/nphoton.2013.29Hu, H., Strybulevych, A., Page, J. H., Skipetrov, S. E., & van Tiggelen, B. A. (2008). Localization of ultrasound in a three-dimensional elastic network. Nature Physics, 4(12), 945-948. doi:10.1038/nphys1101Sperling, T., Bührer, W., Aegerter, C. M., & Maret, G. (2012). Direct determination of the transition to localization of light in three dimensions. Nature Photonics, 7(1), 48-52. doi:10.1038/nphoton.2012.313Fan, Y., Percus, J. K., Stillinger, D. K., & Stillinger, F. H. (1991). Constraints on collective density variables: One dimension. Physical Review A, 44(4), 2394-2402. doi:10.1103/physreva.44.2394Kuhl, U., Izrailev, F. M., Krokhin, A. A., & Stöckmann, H.-J. (2000). Experimental observation of the mobility edge in a waveguide with correlated disorder. Applied Physics Letters, 77(5), 633-635. doi:10.1063/1.127068Torquato, S. (2002). Random Heterogeneous Materials. Interdisciplinary Applied Mathematics. doi:10.1007/978-1-4757-6355-3Uche, O. U., Stillinger, F. H., & Torquato, S. (2004). Constraints on collective density variables: Two dimensions. Physical Review E, 70(4). doi:10.1103/physreve.70.046122Kuhl, U., Izrailev, F. M., & Krokhin, A. A. (2008). Enhancement of Localization in One-Dimensional Random Potentials with Long-Range Correlations. Physical Review Letters, 100(12). doi:10.1103/physrevlett.100.126402Batten, R. D., Stillinger, F. H., & Torquato, S. (2008). Classical disordered ground states: Super-ideal gases and stealth and equi-luminous materials. Journal of Applied Physics, 104(3), 033504. doi:10.1063/1.2961314Florescu, M., Torquato, S., & Steinhardt, P. J. (2009). Designer disordered materials with large, complete photonic band gaps. Proceedings of the National Academy of Sciences, 106(49), 20658-20663. doi:10.1073/pnas.0907744106Dietz, O., Kuhl, U., Hernández-Herrejón, J. C., & Tessieri, L. (2012). Transmission in waveguides with compositional and structural disorder: experimental effects of disorder cross-correlations. New Journal of Physics, 14(1), 013048. doi:10.1088/1367-2630/14/1/013048Man, W., Florescu, M., Williamson, E. P., He, Y., Hashemizad, S. R., Leung, B. Y. C., … Steinhardt, P. J. (2013). Isotropic band gaps and freeform waveguides observed in hyperuniform disordered photonic solids. Proceedings of the National Academy of Sciences, 110(40), 15886-15891. doi:10.1073/pnas.1307879110Man, W., Florescu, M., Matsuyama, K., Yadak, P., Nahal, G., Hashemizad, S., … Chaikin, P. (2013). Photonic band gap in isotropic hyperuniform disordered solids with low dielectric contrast. Optics Express, 21(17), 19972. doi:10.1364/oe.21.019972Torquato, S. (2016). Hyperuniformity and its generalizations. Physical Review E, 94(2). doi:10.1103/physreve.94.022122Torquato, S., Zhang, G., & Stillinger, F. H. (2015). Ensemble Theory for Stealthy Hyperuniform Disordered Ground States. Physical Review X, 5(2). doi:10.1103/physrevx.5.021020Leseur, O., Pierrat, R., & Carminati, R. (2016). High-density hyperuniform materials can be transparent. Optica, 3(7), 763. doi:10.1364/optica.3.000763Gkantzounis, G., Amoah, T., & Florescu, M. (2017). 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Multimode solutions of first-order elliptic quasilinear systems obtained from Riemann invariants

Two new approaches to solving first-order quasilinear elliptic systems of PDEs in many dimensions are proposed. The first method is based on an analysis of multimode solutions expressible in terms of Riemann invariants, based on links between two techniques, that of the symmetry reduction method and of the generalized method of characteristics. A variant of the conditional symmetry method for constructing this type of solution is proposed. A specific feature of that approach is an algebraic-geometric point of view, which allows the introduction of specific first-order side conditions consistent with the original system of PDEs, leading to a generalization of the Riemann invariant method for solving elliptic homogeneous systems of PDEs. A further generalization of the Riemann invariants method to the case of inhomogeneous systems, based on the introduction of specific rotation matrices, enables us to weaken the integrability condition. It allows us to establish a connection between the structure of the set of integral elements and the possibility of constructing specific classes of simple mode solutions. These theoretical considerations are illustrated by the examples of an ideal plastic flow in its elliptic region and a system describing a nonlinear interaction of waves and particles. Several new classes of solutions are obtained in explicit form, including the general integral for the latter system of equations

The distribution and movement patterns of four woodland caribou herds in Quebec and Labrador

Recent studies of woodland caribou (Rangifer tarandus caribou) in northern Quebec and central Labrador have demonstrated similar patterns of seasonal movements and distribution among four herds. Aerial surveys and radio-telemetry indicated that animals occupied forest-wetland habitat at densities of 0.03 caribou km2, or lower, for most of the year. Although females were widely dispersed at calving individuals demonstrated fidelity toward specific calving locations, in successive years. Caribou did not form large post-calving aggregations. Movement was greatest in the spring, prior to calving, and in the fall, during or immediately after rutting. Caribou were generally sedentary during summer and winter, although some moved relatively long distances to late-winter range. Although the herds occupy continuous range across Quebec and Labrador, our data indicate that the herds are largely discreete and should be managed individually

Review: Towards the agroecological management of ruminants, pigs and poultry through the development of sustainable breeding programmes. II. Breeding strategies

Agroecology uses ecological processes and local resources rather than chemical inputs to develop productive and resilient livestock and crop production systems. In this context, breeding innovations are necessary to obtain animals that are both productive and adapted to a broad range of local contexts and diversity of systems. Breeding strategies to promote agroecological systems are similar for different animal species. However, current practices differ regarding the breeding of ruminants, pigs and poultry. Ruminant breeding is still an open system where farmers continue to choose their own breeds and strategies. Conversely, pig and poultry breeding is more or less the exclusive domain of international breeding companies which supply farmers with hybrid animals. Innovations in breeding strategies must therefore be adapted to the different species. In developed countries, reorienting current breeding programmes seems to be more effective than developing programmes dedicated to agroecological systems that will struggle to be really effective because of the small size of the populations currently concerned by such systems. Particular attention needs to be paid to determining the respective usefulness of cross-breeding v. straight breeding strategies of well-adapted local breeds. While cross-breeding may offer some immediate benefits in terms of improving certain traits that enable the animals to adapt well to local environmental conditions, it may be difficult to sustain these benefits in the longer term and could also induce an important loss of genetic diversity if the initial pure-bred populations are no longer produced. As well as supporting the value of within-breed diversity, we must preserve between-breed diversity in order to maintain numerous options for adaptation to a variety of production environments and contexts. This may involve specific public policies to maintain and characterize local breeds (in terms of both phenotypes and genotypes), which could be used more effectively if they benefited from the scientific and technical resources currently available for more common breeds. Last but not least, public policies need to enable improved information concerning the genetic resources and breeding tools available for the agroecological management of livestock production systems, and facilitate its assimilation by farmers and farm technicians

Earthquake lubrication and healing explained by amorphous nanosilica

During earthquake propagation, geologic faults lose their strength, then strengthen as slip slows and stops. Many slip-weakening mechanisms are active in the upper-mid crust, but healing is not always well-explained. Here we show that the distinct structure and rate-dependent properties of amorphous nanopowder (not silica gel) formed by grinding of quartz can cause extreme strength loss at high slip rates. We propose a weakening and related strengthening mechanism that may act throughout the quartz-bearing continental crust. The action of two slip rate-dependent mechanisms offers a plausible explanation for the observed weakening: thermally-enhanced plasticity, and particulate flow aided by hydrodynamic lubrication. Rapid cooling of the particles causes rapid strengthening, and inter-particle bonds form at longer timescales. The timescales of these two processes correspond to the timescales of post-seismic healing observed in earthquakes. In natural faults, this nanopowder crystallizes to quartz over 10s–100s years, leaving veins which may be indistinguishable from common quartz veins