Monosynaptic connections between pairs of spiny stellate cells in layer 4 and pyramidal cells in layer 5A indicate that lemniscal and paralemniscal afferent pathways converge in the infragranular somatosensory cortex.

Monosynaptic interlaminar connections between spiny stellate cells in layer 4 (L4), the main cortical recipient layer for thalamic projections, and pyramidal cells in layer 5A (L5A), one of the main cortical output layers, were examined anatomically and functionally by paired recordings in acute brain slices. The somata of pairs forming interlaminar L4-to-L5A connections were located predominantly close to or directly under the barrel-septum wall in layer 4. Superposition of spiny stellate axon arbors and L5A pyramidal cell dendritic arbors suggested an innervation domain underneath an L4 barrel wall. Functionally, the L4-to-L5A connections were of high reliability and relatively low efficacy, with a unitary EPSP amplitude of 0.6 mV, and the connectivity was moderately high (one in seven pairs tested was connected). The EPSP amplitude was weakly depressing (paired-pulse ratio of approximately 0.8) during repetitive presynaptic action potentials at 10 Hz. The existence of Monosynaptic L4-to-L5A connections indicates that the specific 'lemniscal' thalamic input from the ventro-basal nucleus of the thalamus to the cortex and the more unspecific 'paralemniscal' afferent thalamic projections from the posterior medial nucleus of the thalamus merge already at an initial stage of cortical signal processing. These Monosynaptic connections establish a Monosynaptic coupling of the input to the cortex and its output, thereby effectively bypassing the supragranular layers

Sympathetic cooling of 4^4He+^+ ions in a radiofrequency trap

We have generated Coulomb crystals of ultracold $^4$He$^+$ ions in a linear radiofrequency trap, by sympathetic cooling via laser--cooled $^9$Be$^+$. Stable crystals containing up to 150 localized He$^+$ ions at $\sim$20 mK were obtained. Ensembles or single ultracold He$^+$ ions open up interesting perspectives for performing precision tests of QED and measurements of nuclear radii. The present work also indicates the feasibility of cooling and crystallizing highly charged atomic ions using $^9$Be$^+$ as coolant.Comment: 4 pages, 2 figure

Pareto optimality in house allocation problems

We study Pareto optimal matchings in the context of house allocation problems. We present an O(\sqrt{n}m) algorithm, based on Gales Top Trading Cycles Method, for finding a maximum cardinality Pareto optimal matching, where n is the number of agents and m is the total length of the preference lists. By contrast, we show that the problem of finding a minimum cardinality Pareto optimal matching is NP-hard, though approximable within a factor of 2. We then show that there exist Pareto optimal matchings of all sizes between a minimum and maximum cardinality Pareto optimal matching. Finally, we introduce the concept of a signature, which allows us to give a characterization, checkable in linear time, of instances that admit a unique Pareto optimal matching

Evolution of magnetic states in frustrated diamond lattice antiferromagnetic Co(Al1-xCox)2O4 spinels

Using neutron powder diffraction and Monte-Carlo simulations we show that a spin-liquid regime emerges at $all compositions in the diamond-lattice antiferromagnets Co(Al1-xCox)2O4. This spin-liquid regime induced by frustration due to the second-neighbour exchange coupling J2, is gradually superseded by antiferromagnetic collinear long-range order (k=0) at low temperatures. Upon substitution of Al3+ by Co3+ in the octahedral B-site the temperature range occupied by the spin-liquid regime narrows and TN increases. To explain the experimental observations we considered magnetic anisotropy D or third-neighbour exchange coupling J3 as degeneracy-breaking perturbations. We conclude that Co(Al1-xCox)2O4 is below the theoretical critical point J2/J1=1/8, and that magnetic anisotropy assists in selecting a collinear long-range ordered ground state, which becomes more stable with increasing x due to a higher efficiency of O-Co3+-O as an interaction path compared to O-Al3+-O

The influence of anaerobic muscle activity, maturation and season on the flesh quality of farmed turbot

In order to test seasonal, rearing, maturing and anaerobic muscle activity effect on the flesh quality of turbot (Scophthalmus maximus) a total of 80 farmed turbot from three different strains from reared under natural or continuous light were killed by a percussive blow to the head in November (winter, Icelandic strain), March (spring, Portuguese strain) and June (summer, domesticated strain (France turbot)). To test the effect of anaerobic muscle activity, 10 fish were on each occasion pre rigor filleted, where one fillet was used as a control, while the other fillet was electrically stimulated using a squared 5 Hz, 10 V pulsed DC for 3 min. All pre rigor fillets were measured for pH, weighed, wrapped in aluminum foil and stored in polystyrene boxes with ice. After 7 days of storage the fillets were measured instrumentally for pH, drip loss, colour (CIE L* a* b*) and texture properties such as hardness and shear force, while fillet shrinkage and colour (RBG) were evaluated with computer imaging on photographs from a standard lightbox. Results showed that softness of the flesh was mainly influenced by factors associated with growth, such as season, photoperiod and maturation. Anaerobic muscle activity simulated with electrical stimulation caused an increase in drip loss (<1%) and loss of shear force (<4%), but had no effect on hardness or fillet shrinkage. Computer imaging revealed that muscle contractions related to the electrical stimulus forced out blood from the fillet causing less reddishness for the entire storage period. We conclude that a pH drop upon slaughter associated with anaerobic muscle activity has a minor effect on the flesh quality in the short run, while seasonal/alternatively genetic effects are predominant

Étude du colmatage de membranes d'osmose inverse utilisées pour la préparation des eaux de dialyse rénale

L'osmose inverse est l'élément clef de la production d'eau ultrapure servant dans la préparation du liquide de dialyse rénale. Le vieillissement des membranes d'osmose inverse se traduit par une dérive croissante de la conductivité en sortie de membrane et par une augmentation de la teneur en bactéries dans le perméat délivré en sortie d'osmose inverse, entraînant un risque de contamination pour le patient.Les suivis en conductivité et numérations bactériennes dans la chaîne de production d'eau osmosée de l'Hôpital de Colmar (France) montre un fort dysfonctionnement au niveau des prétraitements et notamment du charbon actif, siège d'une importante prolifération bactérienne (2.3 103 colonies pour 100 ml en amont du charbon actif , 1.1 105 pour 100 ml en aval). Une étude de corrélations entre entrée et sortie d'osmoseurs montre que la forte teneur en germes en sortie du charbon actif est directement responsable de la présence des bactéries dans le perméat.Des tests hydrauliques effectués sur les membranes après quatre années d'utilisation intensive (6500 heures par an), permettent d'identifier les mécanismes prépondérants de vieillissement et de colmatage des membranes utilisées à l'hôpital de Colmar (compaction, formation d'un dépôt et altération de structure).Afin d'identifier les substances colmatantes non retenues par le prétraitement, le film colmatant est analysé par analyse élémentaire, spectrophotométrie infrarouge, diffraction X et zêtamétrie, ce qui nous a permis de mettre en évidence la présence notamment d'argiles, de silice et de substances humiques.The use of reverse osmosis to produce ultrapure water for kidney patients is very prevalent at the present time. About 20000 patients are treated every day in France and the cost of treatment is estimated at 10 thousand million French francs. The patients are provided with a permeate which in principle contains neither ions nor bacteria, which can cause disease and irreversible alteration of the upper-arm articulations. After several months of utilization, the presence of a foulant deposit and biofilm proliferation is often noted on the thin layered active surface of the polyamide membranes. In many cases, the membrane may become irreversibly fouled and require replacement.The aim of this work was to determine the causes of membrane fouling at a reverse osmosis plant in "Hôpital Pasteur" (Colmar, France). First we analyzed the ion-rejection capacity of membranes and the evolution of conductivity over 200 weeks. We observed an increasing drift in conductivity, which could not be halted by cleaning and regeneration procedures. In the second phase of the study, we carried out microbiological studies at many sampling points of the ultrapure water plant in "Hôpital Pasteur". We noted a very important proliferation of bacteria downstream of the pretreatments. The activated charcoal unit is responsible for this problem (2.3 x 103 UFC / 100 mL upstream from the activated charcoal bed, 1.1 x 105 UFC / 100 mL downstream). We noted an important dysfunction in the pretreatment, essentially attributable to the activated charcoal (bacteria) and the resins (silica).We performed tests with x-ray diffraction as a rapid method to determine the crystalline forms present. In the foulant deposits, we found quartz and clay. Infrared spectroscopy is useful in determining the type of organic constituents; in our deposits we noted the presence of humic materials. The analysis of those deposits gave essentially carbon and silicon. The foulant deposits were of organic and crystalline origins