2,838 research outputs found
Is durum wheat-winter pea intercropping efficient to reduce pests and diseases ?
Intercropping (IC) is known as an agricultural practice which can improve the use of environmental resources (light, nutrients and water) resulting in yield advantages compared to sole cropping (SC) (Willey, 1979) particularly in low input systems. But, diseases ands pests can strongly affect both yield and grain quality in such systems. Now, numerous studies have shown significant reductions in harmful insects and on diseases in IC compared to SC of the same species (Vandermeer, 1989; Kinane and Lyngkjaer, 2002) even if others studies did not confirmed these foundings. The aim of our study was to evaluate the assumption that IC can reduce pea pests (green aphids and weevils), pea ascochyta and main durum wheat diseases (mildew, brown rust, fusarium and septoria)
Euclid in a Taxicab: Sparse Blind Deconvolution with Smoothed l1/l2 Regularization
The l1/l2 ratio regularization function has shown good performance for
retrieving sparse signals in a number of recent works, in the context of blind
deconvolution. Indeed, it benefits from a scale invariance property much
desirable in the blind context. However, the l1/l2 function raises some
difficulties when solving the nonconvex and nonsmooth minimization problems
resulting from the use of such a penalty term in current restoration methods.
In this paper, we propose a new penalty based on a smooth approximation to the
l1/l2 function. In addition, we develop a proximal-based algorithm to solve
variational problems involving this function and we derive theoretical
convergence results. We demonstrate the effectiveness of our method through a
comparison with a recent alternating optimization strategy dealing with the
exact l1/l2 term, on an application to seismic data blind deconvolution.Comment: 5 page
PENDANTSS: PEnalized Norm-ratios Disentangling Additive Noise, Trend and Sparse Spikes
Denoising, detrending, deconvolution: usual restoration tasks, traditionally
decoupled. Coupled formulations entail complex ill-posed inverse problems. We
propose PENDANTSS for joint trend removal and blind deconvolution of sparse
peak-like signals. It blends a parsimonious prior with the hypothesis that
smooth trend and noise can somewhat be separated by low-pass filtering. We
combine the generalized quasi-norm ratio SOOT/SPOQ sparse penalties
with the BEADS ternary assisted source separation algorithm.
This results in a both convergent and efficient tool, with a novel Trust-Region
block alternating variable metric forward-backward approach. It outperforms
comparable methods, when applied to typically peaked analytical chemistry
signals. Reproducible code is provided
The role of invariant line junctions in object and visual word recognition
AbstractObject recognition relies heavily on invariant visual features such as the manner in which lines meet at vertices to form viewpoint-invariant junctions (e.g. T, L). We wondered whether these features also underlie readersâ competence for fast recognition of printed words. Since reading is far too recent to have exerted any evolutionary pressure on brain evolution, visual word recognition might be based on pre-existing mechanisms common to all visual object recognition. In a naming task, we presented partially deleted pictures of objects and printed words in which either the vertices or the line midsegments were preserved. Subjects showed an identical pattern of behavior with both objects and words: they made fewer errors and were faster to respond when vertices were preserved. Our results suggest that vertex invariants are used for object recognition and that this evolutionarily ancient mechanism is being co-opted for reading
Itch characteristics in five dermatoses: non-atopic eczema, atopic dermatitis, urticaria, psoriasis and scabies.
International audienceItch is a frequent symptom in many diseases. Some studies have used questionnaires to evaluate pruritus by targeting a single type of dermatitis, for example, studying atopic dermatitis (AD) with the "Eppendorf Itch Questionnaire"(1, 2), and uraemic pruritus (3). Questionnaires have also been used to study psoriasis (4) and urticaria (5). The pathophysiological mechanisms of itch, especially with regard to the mediators and transmitters involved, can vary according to the itch-inducing disease. It is possible that itching sensations may be experienced differently by each patient and depending on the underlying disease. O'Neill et al. (6) and Reich et al. (7) have shown that itching sensations can vary between various skin diseases. The present study used an exploratory approach to highlight the qualitative (symptomatological) features of pruritus in different dermatoses, using a non-validated questionnaire in French, adapted from previous questionnaires (1, 2)
Fragmentation de grains de sable. Suivi par Ă©mission acoustique et bilans de population.
6 pagesDevenue trĂšs courante dans le domaine du contrĂŽle non destructif, l'Ă©tude des ondes acoustiques est beaucoup moins utilisĂ©e pour suivre l'Ă©volution de certains phĂ©nomĂšnes. Pourtant elle peut se rĂ©vĂ©ler utile, notamment pour caractĂ©riser les phĂ©nomĂšnes intervenant lors de la compression des poudres. L'analyse de l'Ă©mission acoustique (E.A.) au cours de la compression de plusieurs poudres pharmaceutiques telles que l'aspirine, l'amidon, le saccharose et le kĂ©toprofĂšne a permis de mieux cerner les phĂ©nomĂšnes qui se produisent pendant la formation du comprimĂ© [1,2]. Les ondes acoustiques Ă©mises par la poudre dĂ©pendent des phĂ©nomĂšnes se produisant pendant la compression, tels que le rĂ©arrangement granulaire, la fragmentation et la dĂ©formation plastique des grains. Serris [1,2] a Ă©galement remarquĂ© que l'intensitĂ© de l'Ă©mission acoustique est fonction de la poudre. L'Ă©mission d'ondes acoustiques peut alors ĂȘtre considĂ©rĂ©e comme une caractĂ©ristique intrinsĂšque d'une poudre
Influence of temperature on the compaction of an organic powder and the mechanical strength of tablets.
International audienceThe purpose of this work consists in following the dependence of physical properties on the temperature during the compaction of an organic component. A special thermo-regulated die has been developed to realize uniaxial compression at different constant temperatures. This study has shown that a temperature change modifies the microstructures and the mechanical behaviour of the tablets. The measurement of the tablet porosity during the compression cycle allows us to conclude that temperature influences mainly the phenomena occurring during the isobaric stage of the compression cycle and not the ones during the pressure increase. On the other hand, during the pressure increase, the acoustical activity of the powder is reduced when temperature increases. The tensile strength of tablets realized at different temperatures was also studied and shows a maximum around 60°C that can be explained by the SEM analysis of the microstructure of the tablets
Improved Immunological Tolerance Following Combination Therapy with CTLA-4/Ig and AAV-Mediated PD-L1/2 Muscle Gene Transfer
Initially thought as being non-immunogenic, recombinant AAVs have emerged as efficient vector candidates for treating monogenic diseases. It is now clear however that they induce potent immune responses against transgene products which can lead to destruction of transduced cells. Therefore, developing strategies to circumvent these immune responses and facilitate long-term expression of transgenic therapeutic proteins is a main challenge in gene therapy. We evaluated herein a strategy to inhibit the undesirable immune activation that follows muscle gene transfer by administration of CTLA-4/Ig to block the costimulatory signals required early during immune priming and by using gene transfer of PD-1 ligands to inhibit T cell functions at the tissue sites. We provide the proof of principle that this combination immunoregulatory therapy targeting two non-redundant checkpoints of the immune response, i.e., priming and effector functions, can improve persistence of transduced cells in experimental settings where cytotoxic T cells escape initial blockade. Therefore, CTLA-4/Ig plus PD-L1/2 combination therapy represents a candidate approach to circumvent the bottleneck of immune responses directed toward transgene products
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