Pierre-and-Marie-Curie University

About: Pierre-and-Marie-Curie University is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Raman spectroscopy. The organization has 34448 authors who have published 56139 publications receiving 2392398 citations.

Study of the B- → J/ΨK -π+π- decay and measurement of the B - → X(3872)K- branching fraction

Abstract: The authors study the decay B{sup -} {yields} J/{psi}K{sup -}{pi}{sup +}{pi}{sup -} using 117 million B{bar B} events collected at the {Upsilon}(4S) resonance with the BaBar detector at the PEP-II e{sup +}e{sup -} asymmetric-energy storage ring. They measure the branching fractions {Beta}(B{sup -} {yields} J/{psi}K{sup -} {pi}{sup +}{pi}{sup -}) = (116 {+-} 7(stat.) {+-} 9(syst.)) x 10{sup -5} and {Beta}(B{sup -} {yields} X(3872)K{sup -}) x {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) = (1.28 {+-} 0.41) x 10{sup -5} and find the mass of the X(3872) to be 3873.4 {+-} 1.4MeV/c{sup 2}. They search for the h{sub c} narrow state in the decay B{sup -} {yields} h{sub c} K{sup -}, h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -} and for the decay B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}, with D{sup 0} {yields} K{sup -}{pi}{sup +}. They set the 90% C.L. limits {Beta}(B{sup -} {yields} h{sub c}K{sup -}) x {Beta}(h{sub c} {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 3.4 x 10{sup -6} and {Beta}(B{sup -} {yields} J/{psi}D{sup 0}{pi}{sup -}) < 5.2 x 10{sup -5}.

Foundations of human reasoning in the prefrontal cortex

Abstract: The prefrontal cortex (PFC) subserves reasoning in the service of adaptive behavior. Little is known, however, about the architecture of reasoning processes in the PFC. Using computational modeling and neuroimaging, we show here that the human PFC has two concurrent inferential tracks: (i) one from ventromedial to dorsomedial PFC regions that makes probabilistic inferences about the reliability of the ongoing behavioral strategy and arbitrates between adjusting this strategy versus exploring new ones from long-term memory, and (ii) another from polar to lateral PFC regions that makes probabilistic inferences about the reliability of two or three alternative strategies and arbitrates between exploring new strategies versus exploiting these alternative ones. The two tracks interact and, along with the striatum, realize hypothesis testing for accepting versus rejecting newly created strategies.

Optical efficiency factors of some phytoplankters1

Abstract: Absorption and total scattering coefficients of four phytoplankton species grown in batch cultures were measured simultaneously. Backscattering coefficients were obtained by using an integrating sphere. These coefficients are transformed into specific coefficients, i.e. related to a unit of concentration in chlorophyll a, and also into dimensionless efficiency factors characteristic of the cells. The specific coefficients differ noticeably from one species to another. Total scattering and backscattering coefficients are clearly depressed near and inside the absorption bands. These minima can be interpreted by combining the theory of anomalous dispersion with Mie-Lorentz theory applied to polydisperse suspensions. The backscattering efficiency (ratio of backscattering to total scattering) of algal cells appears to be very low (typically ~0.1%). These different results must be taken into consideration when interpreting and modeling the optical properties of seawater, particularly ocean color. They also must be considered when modeling photosynthesis, since the variations in the light-harvesting ability of the cells intervene directly in the quantum yield estimate. The optical properties of natural waters depart from those of ideally pure water because of the presence, in variable amounts, of diverse dissolved and particulate substances. From an optical point of view, these can be considered as belonging to four groups: live algal cells; biogenous detritus associated with and deriving from these algae; terrigenous particles and resuspended sediment; and dissolved organic (yellow) substances. Of these, phytoplankton, as the only primary producer in the pelagic environment, is of particular interest. In addition, the algal cells and their debris predominantly determine the optical properties of the water in the open sea, away from land and bottom influence. Depending on the physiological state of the algae and on environmental conditions, primary production is effected through photosynthesis, with a varying yield. Such a yield, estimated on a quan