Impact of the commercial fishery on the population of bait shrimp (Penaeus spp.) in Biscayne Bay, 1986

Monthly population size of bait shrimp in the Bay was estimated from December 1984 to July 1985. Growth rates for male and female P. duorarum showed that pink shrimp exhibit a mean residence time in the nursery area (Biscayne Bay) of approximately 21 weeks. Monthly mortality rates were determined for each sex of pink shrimp. It was estimated that 23% and 26% of the male and female monthly population size, respectively, was absorbed by both the fishery and ecosystem monthly. Monthly proportion of the standing stock expected to die exclusively through fishing was 6.5% and 6.0% for males and females respectively. Estimates of emigration rates showed that approximately 4.0% of the population was lost from the Bay system each month. This surplus production was about 50% of the average monthly catch by the fleet. Fishing mortality represents only 8 - 9% of the losses to the shrimp population. The biggest source of loss is emigration, suggesting that most shrimp beyond the size at recruitment (to the fishery) are not utilized for food while in the Bay. Thus, it appears that the direct impact of the fishery on the bait shrimp population is relatively small. (PDF contains 46 pages

Performance of the CDF Calorimeter Simulation in Tevatron Run II

The CDF experiment is successfully collecting data from ppbar collisions at the Tevatron in Run II. As the data samples are getting larger, systematic uncertainties due to the measurement of the jet energy scale assessed using the calorimeter simulation have become increasingly important. In many years of operation, the collaboration has gained experience with GFLASH, a fast parametrization of electromagnetic and hadronic showers used for the calorimeter simulation. We present the performance of the calorimeter simulation and report on recent improvements based on a refined in situ tuning technique. The central calorimeter response is reproduced with a precision of 1-2%.Comment: 8 pages, 4 figures; LaTeX2e, 10 .eps files, uses aipproc.cls, aipxfm.sty and aip-6s.clo (included). Contribution to the Proceedings of the 12th International Conference on Calorimetry in High Energy Physics (CALOR06), June 5-9, 2006, Chicago (IL), USA. To be published by American Institute of Physics (AIP

Bait shrimp fishery of Biscayne Bay

A small but valuable live bait shrimp fishery has existed in Biscayne Bay since at least the early 1950s. In recent years there has been increasing pressure from recreational fishing and environmental groups to eliminate this fishery from the Bay because the fishing activity is generally thought to be deleterious to the environment and/or destructive to juvenile game fish. This study was initiated to update the existing knowledge of the bait shrimp fishery in Biscayne Bay and document historical trends in number of participants, fishing methods, fishing area, seasonality, total catch, catch-per-unit-effort, disposition of the catch, and economics of the industry. (21pp.

Anomaly-Free Sets of Fermions

We present new techniques for finding anomaly-free sets of fermions. Although the anomaly cancellation conditions typically include cubic equations with integer variables that cannot be solved in general, we prove by construction that any chiral set of fermions can be embedded in a larger set of fermions which is chiral and anomaly-free. Applying these techniques to extensions of the Standard Model, we find anomaly-free models that have arbitrary quark and lepton charges under an additional U(1) gauge group.Comment: 21 (+1) page

Diffuse Interstellar Bands in z < 0.6 CaII Absorbers

The diffuse interstellar bands (DIBs) probably arise from complex organic molecules whose strength in local galaxies correlates with neutral hydrogen column density, N(HI), and dust reddening, E(B-V). Since CaII absorbers in quasar (QSO) spectra are posited to have high N(HI) and significant E(B-V), they represent promising sites for the detection of DIBs at cosmological distances. Here we present the results from the first search for DIBs in 9 CaII-selected absorbers at 0.07 < z_abs < 0.55. We detect the 5780Ang DIB in one line of sight at z_abs = 0.1556; this is only the second QSO absorber in which a DIB has been detected. Unlike the majority of local DIB sight-lines, both QSO absorbers with detected DIBs show weak 6284Ang absorption compared with the 5780Ang band. This may be indicative of different physical conditions in intermediate redshift QSO absorbers compared with local galaxies. Assuming that local relations between the 5780Ang DIB strength and N(HI) and E(B-V) apply in QSO absorbers, DIB detections and limits can be used to derive N(HI) and E(B-V). For the one absorber in this study with a detected DIB, we derive E(B-V) = 0.23mag and log[N(HI)] >= 20.9, consistent with previous conclusions that CaII systems have high HI column densities and significant reddening. For the remaining 8 CaII-selected absorbers with 5780Ang DIB non-detections, we derive E(B-V) upper limits of 0.1-0.3mag.Comment: 5 pages, 2 figures. Accepted to MNRAS Letter

Maturity, ovarian cycle, fecundity, and age-specific parturition of black rockfish (Sebastes melanops)

From 1995 to 1998, we collected female black rockfish (Sebastes melanops) off Oregon in order to describe their basic reproductive life history and determine age-specific fecundity and temporal patterns in parturition. Female black rockfish had a 50% probability of being mature at 394 mm fork length and 7.5 years-of-age. The proportion of mature fish age 10 or older significantly decreased each year of this study, from 0.511 in 1996 to 0.145 in 1998. Parturition occurred between mid-January and mid-March, and peaked in February. We observed a trend of older females extruding larvae earlier in the spawning season and of younger fish primarily responsible for larval production during the later part of the season. There were differences in absolute fecundity at age between female black rockfish with prefertilization oocytes and female black rockfish with fertilized eggs; fertilized-egg fecundity estimates were considered superior. The likelihood of yolked oocytes reaching the developing embryo stage increased with maternal age. Absolute fecundity estimates (based on fertilized eggs) ranged from 299,302 embryos for a 6-year-old female to 948,152 embryos for a 16-year-old female. Relative fecundity (based on fertilized eggs) increased with age from 374 eggs/g for fish age 6 to 549 eggs/g for fish age 16

Monte Carlo Comparisons to a Cryogenic Dark Matter Search Detector with low Transition-Edge-Sensor Transition Temperature

We present results on phonon quasidiffusion and Transition Edge Sensor (TES) studies in a large, 3 inch diameter, 1 inch thick [100] high purity germanium crystal, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare calibration data with results from a Monte Carlo which includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels. The phonon energy is then parsed into TES based phonon readout channels and input into a TES simulator

Darboux transformations with tetrahedral reduction group and related integrable systems

In this paper, we derive new two-component integrable differential difference and partial difference systems by applying a Lax-Darboux scheme to an operator formed from a