Marine Biodiversity in the Caribbean: Regional Estimates and Distribution Patterns

This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela – Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of different taxa

Measurement of the Pseudorapidity and Centrality Dependence of the Transverse Energy Density in Pb-Pb Collisions at √sNN=2.76 TeV

The transverse energy (E-T) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (root s(NN)) has been measured over a broad range of pseudorapidity (eta) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE(T)/d eta) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities, the transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from eta = 0 to vertical bar eta vertical bar = 5.0. For the 5% most central collisions, the energy density per unit volume is estimated to be about 14 GeV/fm(3) at a time of 1 fm/c after the collision. This is about 100 times larger than normal nuclear matter density and a factor of 2.6 times higher than the energy density reported at root s(NN) = 200 GeV at the Relativistic Heavy Ion Collider

Measurement of the differential cross section for isolated prompt photon production in pp collisions at 7 TeV

A measurement of the differential cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a center-of-mass energy of 7 TeV is presented. The data sample corresponds to an integrated luminosity of 36 pb(-1) recorded by the CMS detector at the LHC. The measurement covers the pseudorapidity range vertical bar eta vertical bar < 2.5 and the transverse energy range 25 < E-T < 400 GeV, corresponding to the kinematic region 0.007 < x(T) < 0.114. Photon candidates are identified with two complementary methods, one based on photon conversions in the silicon tracker and the other on isolated energy deposits in the electromagnetic calorimeter. The measured cross section is presented as a function of E-T in four pseudorapidity regions. The next-to-leading-order perturbative QCD calculations are consistent with the measured cross section

Measurement of the weak mixing angle with the Drell-Yan process in proton-proton collisions at the LHC

This is the Pre-Print version of the Article - Copyright @ 2011 APSA multivariate likelihood method to measure electroweak couplings with the Drell-Yan process at the LHC is presented. The process is described by the dilepton rapidity, invariant mass, and decay angle distributions. The decay angle ambiguity due to the unknown assignment of the scattered constituent quark and antiquark to the two protons in a collision is resolved statistically using correlations between the observables. The method is applied to a sample of dimuon events from proton-proton collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 1.1 inverse femtobarns. From the dominant u-ubar, d-dbar to gamma*/Z to opposite sign dimuons process, the effective weak mixing angle parameter is measured to be sin^2(theta[eff]) = 0.2287 +/- 0.0020 (stat.) +/- 0.0025 (syst.). This result is consistent with measurements from other processes, as expected within the standard model