Les Algues Dasycladales du Permien et du Trias. Nouvelle tentative d’inventaire bibliographique, géographique et stratigraphique

The present work enlists as comprehensively as possible the Permian and Triassic Dasyclad algae. For each species, localities and stratigraphic positions attached to the quoted specimens are detailed within the synonymy lis

Experimental Studies of Prompt Fission Neutron Energy Spectra

AbstractPrompt fission neutron spectra were measured in the reactions 238U(n,f), 235U(n,f) and 237Np(n,f) at different incident neutron energies. The neutrons were detected using a coaxial doped p-terphenyl scintillation detector in coincidence with fission fragments and their time-of-flight was recorded. The properties of the neutron detector were determined and the results are presented in this work. A preliminary neutron detection efficiency was applied to data from the neutron-induced fission of 238U at En = 5.2 MeV, leading to encouraging results

Quarkonia production with the Hera-B experiment

Measurements of the dependence of the J/Psi production cross section on its kinematic variables as well as on the target atomic numbers for 920 GeV/c protons incident on different targets have been made with the Hera-B detector. The large collected di-lepton sample allows to study the production ratio of Psi(2S) to J/Psi and of Chic to J/Psi . We also report on measurements of the b-bbar and Upsilon production cross section.Comment: 9 pages, 11 figure

Influence of ion-to-electron temperature ratio on tearing instability and resulting subion-scale turbulence in a low-βe\beta_e collisionless plasma

A two-field gyrofluid model including ion finite Larmor radius (FLR) corrections, magnetic fluctuations along the ambient field and electron inertia is used to study two-dimensional reconnection in a low $\beta_e$ collisionless plasma, in a plane perpendicular to the ambient field. Both moderate and large values of the ion-to-electron temperature ratio $\tau$ are considered. The linear growth rate of the tearing instability is computed for various values of $\tau$, confirming the convergence to reduced electron magnetodynamics (REMHD) predictions in the large $\tau$ limit. Comparisons with analytical estimates in several limit cases are also presented. The nonlinear dynamics leads to a fully-developed turbulent regime that appears to be sensitive to the value of the parameter $\tau$. For $\tau = 100$, strong large-scale velocity shears trigger Kelvin-Helmholtz instability, leading to the propagation of the turbulence through the separatrices, together with the formation of eddies of size of the order of the electron skin depth. In the $\tau = 1$ regime, the vortices are significantly smaller and their accurate description requires that electron FLR effects be taken into account

Mitochondrial proteomics: analysis of a whole mitochondrial extract with two-dimensional electrophoresis

Mitochondria are complex organelles, and their proteomics analysis requires a combination of techniques. The emphasis in this chapter is made first on mitochondria preparation from cultured mammalian cells, then on the separation of the mitochondrial proteins with two-dimensional electrophoresis (2DE), showing some adjustment over the classical techniques to improve resolution of the mitochondrial proteins. This covers both the protein solubilization, the electrophoretic part per se, and the protein detection on the gels, which makes the interface with the protein identification part relying on mass spectrometry

J/ψJ/\psi production in PHENIX

Heavy quarkonia production is expected to be sensitive to the formation of a quark gluon plasma (QGP). The PHENIX experiment has measured $J/\psi$ production at $\sqrt{s_{NN}}=$~200 GeV in Au+Au and Cu+Cu collisions, as well as in reference p+p and d+Au runs. $J/\psi$'s were measured both at mid ($|y|<0.35$) and forward ($1.2<|y|<2.2$) rapidity. In this letter, we present the A+A preliminary results and compare them to normal cold nuclear matter expectations derived from PHENIX d+Au and p+p measurements as well as to theoretical models including various effects (color screening, recombination, sequential melting...).Comment: 5 pages, 7 figures. To appear in the proceedings of Hot Quarks 2006: Workshop for Young Scientists on the Physics of Ultrarelativistic Nucleus-Nucleus Collisions, Villasimius, Italy, 15-20 May 200

Ozone anomalies in the free troposphere during the COVID-19 pandemic

Using the CAM-chem Model, we simulate the response of chemical species in the free troposphere to scenarios of primary pollutant emission reductions during the COVID-19 pandemic. Zonally averaged ozone in the free troposphere during Northern Hemisphere spring and summer is found to be 5%-15% lower than 19-yr climatological values, in good agreement with observations. About one third of this anomaly is attributed to the reduction scenario of air traffic during the pandemic, another third to the reduction scenario of surface emissions, the remainder to 2020 meteorological conditions, including the exceptional springtime Arctic stratospheric ozone depletion. For the combined emission reductions, the overall COVID-19 reduction in northern hemisphere tropospheric ozone in June is less than 5 ppb below 400 hPa, but reaches 8 ppb at 250 hPa. In the Southern Hemisphere, COVID-19 related ozone reductions by 4%-6% were masked by comparable ozone increases due to other changes in 2020

Electronic sculpting of ligand-GPCR subtype selectivity:the case of angiotensin II

GPCR subtypes possess distinct functional and pharmacological profiles, and thus development of subtype-selective ligands has immense therapeutic potential. This is especially the case for the angiotensin receptor subtypes AT1R and AT2R, where a functional negative control has been described and AT2R activation highlighted as an important cancer drug target. We describe a strategy to fine-tune ligand selectivity for the AT2R/AT1R subtypes through electronic control of ligand aromatic-prolyl interactions. Through this strategy an AT2R high affinity (<i>K</i>_i = 3 nM) agonist analogue that exerted 18,000-fold higher selectivity for AT2R versus AT1R was obtained. We show that this compound is a negative regulator of AT1R signaling since it is able to inhibit MCF-7 breast carcinoma cellular proliferation in the low nanomolar range