A Multi-Year Survey of Meiofaunal Abundance From the Northern Gulf of Mexico Continental Shelf and Slope

This 3-yr (2007–09) survey documented meiofauna abundance across the northern Gulf of Mexico on the continental shelf and slope from south Texas to south Florida. Sediment samples were collected from depths ranging from 29 to 509 m (average = 132 m) on the National Oceanic and Atmospheric Admistration ship Gordon Gunter during the annual fall small pelagics fish-sampling cruise. A total of 259 sediment samples from 99 ShipekH grabs were analyzed. Meiofauna were isolated from the sediment by sieving (63-mm sieve) and concentrating the organisms via LudoxH centrifugation. Each year the two dominant animal groups were nematodes and copepods, followed by polychaetes, nauplii, kinorhynchs, priapulid loricate larvae, tardigrades, and Acari. Spearman correlations indicated that abundances of nematodes, copepods, polychaetes, and nauplii were positively related, and that all meiofauna groups decreased in abundance with increasing longitude (farther west). Abiotic variables such as salinity, temperature, and depth did not correlate with any meiofauna group. Distribution maps of the animals indicated a clear geographic trend that was supported statistically, in that the animal groups were more concentrated in Florida samples rather than the central and western continental shelf

A Multi-Year Survey of Meiofaunal Abundance From the Northern Gulf of Mexico Continental Shelf and Slope

This 3-yr (2007–09) survey documented meiofauna abundance across the northern Gulf of Mexico on the continental shelf and slope from south Texas to south Florida. Sediment samples were collected from depths ranging from 29 to 509 m (average = 132 m) on the National Oceanic and Atmospheric Administration ship Gordon Gunter during the annual fall small pelagics fish-sampling cruise. A total of 259 sediment samples from 99 Shipek® grabs were analyzed. Meiofauna were isolated from the sediment by sieving (63-μm sieve) and concentrating the organisms via Ludox® centrifugation. Each year the two dominant animal groups were nematodes and copepods, followed by polychaetes, nauplii, kinorhynchs, priapulid loricate larvae, tardigrades, and Acari. Spearman correlations indicated that abundances of nematodes, copepods, polychaetes, and nauplii were positively related, and that all meiofauna groups decreased in abundance with increasing longitude (farther west). Abiotic variables such as salinity, temperature, and depth did not correlate with any meiofauna group. Distribution maps of the animals indicated a clear geographic trend that was supported statistically, in that the animal groups were more concentrated in Florida samples rather than the central and western continental shelf

Meiofauna and Trace Metals From Sediment Collections in Florida After the Deepwater Horizon Oil Spill

Sediment from the Florida Gulf continental shelf was collected from 18 sites during October and November 2010 for meiofauna and trace-metals analysis. Collections were obtained using a Shipek® grab on the National Oceanic and Atmospheric Administration ship Pisces and spanned from the head of the DeSoto Canyon to off the southern end of the Florida peninsula approximately following the 100–200-m contour. Mean abundance of the dominant meiofaunal groups (nematodes, copepods, and polychaetes) was unchanged when compared with 2007–2009 data. Nematodes and copepods correlated positively with each other, and negatively with latitude and longitude, suggesting that there were higher densities in southern Florida. These results contrast with those from 2007–2009 in that previously nematodes had no correlation with latitude or longitude in Florida. Nickel (Ni) and vanadium (V) concentrations were higher in the western Florida locations and correlated positively with increasing depth. No relationship was found between Ni, V, and meiofauna densities

Limit on Bs0B^0_s oscillation using a jet charge method

A lower limit is set on the B_{s}^{0} meson oscillation parameter \Delta m_{s} using data collected from 1991 to 1994 by the ALEPH detector. Events with a high transverse momentum lepton and a reconstructed secondary vertex are used. The high transverse momentum leptons are produced mainly by b hadron decays, and the sign of the lepton indicates the particle/antiparticle final state in decays of neutral B mesons. The initial state is determined by a jet charge technique using both sides of the event. A maximum likelihood method is used to set a lower limit of \, \Delta m_{s}. The 95\% confidence level lower limit on \Delta m_s ranges between 5.2 and 6.5(\hbar/c^{2})~ps^{-1} when the fraction of b quarks from Z^0 decays that form B_{s}^{0} mesons is varied from 8\% to 16\%. Assuming that the B_{s}^{0} fraction is 12\%, the lower limit would be \Delta m_{s} 6.1(\hbar/c^{2})~ps^{-1} at 95\% confidence level. For x_s = \Delta m_s \, \tau_{B_s}, this limit also gives x_s 8.8 using the B_{s}^{0} lifetime of \tau_{B_s} = 1.55 \pm 0.11~ps and shifting the central value of \tau_{B_s} down by 1\sigma

Measurement of the Bs0^0_s lifetime and production rate with Ds−l+^-_s l^+ combinations in Z decays

The lifetime of the \bs meson is measured in approximately 3 million hadronic Z decays accumulated using the ALEPH detector at LEP from 1991 to 1994. Seven different \ds decay modes were reconstructed and combined with an opposite sign lepton as evidence of semileptonic \bs decays. Two hundred and eight \dsl candidates satisfy selection criteria designed to ensure precise proper time reconstruction and yield a measured \bs lifetime of \mbox{\result .} Using a larger, less constrained sample of events, the product branching ratio is measured to be \mbox{\pbrresult