Successfull Blossom Thinning and Crop Load Regulation for Organic Apple Growing with Potassium-bi-carbonate (Armicarb(R)): Results of Field Experiments over 3 Years and with 11 Cultivars

With field trials over 3 years in a commercial organic orchard in Switzerland we have tested the efficacy of Armicarb® (potassium-bi-carbonate) for flower thinning in organic apple production. Over time, Armicarb was tested on 11 cultivars, at different application periods, in different concentrations, and always in comparison to other agents that are already allowed for thinning in organic fruit production in the European Union as e.g. lime sulphur, molasses, mechanical rope-thinner or combinations of methods. Armicarb proved to be an efficient and reliable thinning agent with an efficacy similar to the now recommended methods with rope device, molasses or lime sulphur but has the advantage to be an environmentally very friendly product. On the other hand, the risk for fruit russeting is comparably elevated especially with cultivars ‘Elstar’, ‘Golden Del.’ ’and ‘Gala’. Finally, we have elaborated cultivar-specific recommendations for the use of Armicarb for thinning purposes, which were the basis for the Swiss Federal approval to use Armicarb for thinning in conventional and organic apple production in 2011/2012

Optimal branching asymmetry of hydrodynamic pulsatile trees

Most of the studies on optimal transport are done for steady state regime conditions. Yet, there exists numerous examples in living systems where supply tree networks have to deliver products in a limited time due to the pulsatile character of the flow. This is the case for mammals respiration for which air has to reach the gas exchange units before the start of expiration. We report here that introducing a systematic branching asymmetry allows to reduce the average delivery time of the products. It simultaneously increases its robustness against the unevitable variability of sizes related to morphogenesis. We then apply this approach to the human tracheobronchial tree. We show that in this case all extremities are supplied with fresh air, provided that the asymmetry is smaller than a critical threshold which happens to fit with the asymmetry measured in the human lung. This could indicate that the structure is adjusted at the maximum asymmetry level that allows to feed all terminal units with fresh air.Comment: 4 pages, 4 figure

JMC’s Interdisciplinary Smoking Cessation Program

No abstract availabl

Extending Johnson's and Morita's homomorphisms to the mapping class group

We extend certain homomorphisms defined on the higher Torelli subgroups of the mapping class group to crossed homomorphisms defined on the entire mapping class group. In particular, for every $k\geq 2$, we construct a crossed homomorphism $\epsilon_k$ which extends Morita's homomorphism $\tilde \tau_k$ to the entire mapping class group. From this crossed homomorphism we also obtain a crossed homomorphism extending the $k$th Johnson homomorphism $\tau_k$ to the mapping class group. D. Johnson and S. Morita obtained their respective homomorphisms by considering the action of the mapping class group on the nilpotent truncations of the surface group; our approach is to mimic Morita's construction topologically by using nilmanifolds associated to these truncations. This allows us to take the ranges of these crossed homomorphisms to be certain finite-dimensional real vector spaces associated to these nilmanifolds.Comment: 32 pages; cleaned up and minor corrections to proofs; updated to agree with version published by Alg. & Geom. Top at: http://msp.warwick.ac.uk/agt/2007/07/p050.xhtm

Self-buckling and self-writhing of semi-flexible microorganisms

Multi-flagellated microorganisms can buckle and writhe under their own activity as they swim through a viscous fluid. New equilibrium configurations and steady-state dynamics then emerge which depend on the organism's mechanical properties and on the oriented distribution of flagella along its surface. Modeling the cell body as a semi-flexible Kirchhoff rod and coupling the mechanics to a dynamically evolving flagellar orientation field, we derive the Euler-Poincar{\'e} equations governing dynamics of the system, and rationalize experimental observations of buckling and writhing of elongated swarmer {\it P. mirabilis} cells. A sequence of bifurcations is identified as the body is made more compliant, due to both buckling and torsional instabilities. The results suggest that swarmer cells invest no more resources in maintaining membrane integrity than is necessary to prevent self-buckling.Comment: 6 pages, 3 figure

Femmes, islam et identité religieuse dans l'immigration turque en Alsace

La difficile recomposition de l'identité des femmes dans l'immigration en Alsace semble prendre la forme, pour beaucoup, d'une « entrée en islam ». Paradoxalement considérée comme un chemin vers l'émancipation, cette voie débouche souvent sur un pouvoir coercitif exercé par les femmes islamistes envers les autres femmes du groupe

Interplay between geometry and flow distribution in an airway tree

Uniform fluid flow distribution in a symmetric volume can be realized through a symmetric branched tree. It is shown here, however, that the flow partitioning can be highly sensitive to deviations from exact symmetry if inertial effects are present. This is found by direct numerical simulation of the Navier-Stokes equations in a 3D tree geometry. The flow asymmetry is quantified and found to depend on the Reynolds number. Moreover, for a given Reynolds number, we show that the flow distribution depends on the aspect ratio of the branching elements as well as their angular arrangement. Our results indicate that physiological variability should be severely restricted in order to ensure uniform fluid distribution in a tree. This study suggests that any non-uniformity in the air flow distribution in human lungs should be influenced by the respiratory conditions, rest or hard exercise

Global Dimension of Polynomial Rings in Partially Commuting Variables

For any free partially commutative monoid $M(E,I)$, we compute the global dimension of the category of $M(E,I)$-objects in an Abelian category with exact coproducts. As a corollary, we generalize Hilbert's Syzygy Theorem to polynomial rings in partially commuting variables.Comment: 11 pages, 2 figure