Direct tunneling delay time measurement in an optical lattice

We report on the measurement of the time required for a wave packet to tunnel through the potential barriers of an optical lattice. The experiment is carried out by loading adiabatically a Bose-Einstein condensate into a 1D optical lattice. A sudden displacement of the lattice by a few tens of nm excites the micromotion of the dipole mode. We then directly observe in momentum space the splitting of the wave packet at the turning points and measure the delay between the reflected and the tunneled packets for various initial displacements. Using this atomic beam splitter twice, we realize a chain of coherent micron-size Mach-Zehnder interferometers at the exit of which we get essentially a wave packet with a negative momentum, a result opposite to the prediction of classical physics

Learning to Extract Motion from Videos in Convolutional Neural Networks

This paper shows how to extract dense optical flow from videos with a convolutional neural network (CNN). The proposed model constitutes a potential building block for deeper architectures to allow using motion without resorting to an external algorithm, \eg for recognition in videos. We derive our network architecture from signal processing principles to provide desired invariances to image contrast, phase and texture. We constrain weights within the network to enforce strict rotation invariance and substantially reduce the number of parameters to learn. We demonstrate end-to-end training on only 8 sequences of the Middlebury dataset, orders of magnitude less than competing CNN-based motion estimation methods, and obtain comparable performance to classical methods on the Middlebury benchmark. Importantly, our method outputs a distributed representation of motion that allows representing multiple, transparent motions, and dynamic textures. Our contributions on network design and rotation invariance offer insights nonspecific to motion estimation

Ultrarobust calibration of an optical lattice depth based on a phase shift

We report on a new method to calibrate the depth of an optical lattice. It consists in triggering the intrasite dipole mode of the cloud by a sudden phase shift. The corresponding oscillatory motion is directly related to the intraband frequencies on a large range of lattice depths. Remarkably, for a moderate displacement, a single frequency dominates this oscillation for the zeroth and first order interference pattern observed after a sufficiently long time-of-flight. The method is robust against atom-atom interactions and the exact value of the extra external confinement of the initial trapping potential.Comment: 7 pages, 6 figure

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

Multidisciplinary approach to reconstructing local pastoral activities: an example from the Pyrenean Mountains (Pays Basque)

International audienceIn this study archaeology, history and palaeoecology (modern and fossil data sets of pollen and nonpollen palynomorphs) were used to reconstruct small-scale pastoral activities in the Pyrenees Mountains during the last two millennia. Modern pollen assemblages from the major vegetation units (both natural andanthropogenic) are studied on one restricted watershed area. A correlative model (RDA) of 61 modern pollen spectra and 35 external variables distinguishes two groups of taxa, providing information on the nature and spatial extent of human impact on the landscape. The first pool indicates local pastoral activities, and the second one implies regional input from outside the studied watershed, and is not characteristic of a specific land use. These pools are described as 'Local Pastoral Pollen Indicators' (LPPI) for this particular mountain region on crystalline bedrock and 'Regional Human Activities Pollen Indicators' (RHAPI). The modern data set is used to aid interpretation of the local pollen sequence of Sourzay that covers the last 2000 calendar years BP, using RDA reconstructions, and best modern analogues as a means of comparing modern and fossil spectra. The study also demonstrates agreement between the independent interpretations of two fossil proxies, LPPI and coprophilous fungi

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

Conspiracy theory as spatial practice: the case of the Sivas arson attack, Turkey

This article discusses the relationship between conspiratorial thinking and physical space by focusing on the ways conspiracy theories regarding political violence shape and are shaped by the environments in which it is commemorated. Conspiratorial thinking features space as a significant element, but is taken to do so mainly figuratively. In blaming external powers and foreign actors for social ills, conspiracy theorists employ the spatial metaphor of inside versus outside. In perceiving discourses of transparency as the concealment rather than revelation of mechanisms of governance, conspiracy theorists engage the trope of a façade separating the space of power’s formulations from that of its operations. Studying the case of an arson attack dating from 1990s Turkey and its recent commemorations, this article argues that space mediates conspiracy theory not just figuratively but also physically and as such serves to catalyze two of its deadliest characteristics: anonymity and non-linear causality. Attending to this mediation requires a shift of focus from what conspiracy theory is to what it does as a spatial practice