948 resultados para C. Williams
Resumo:
In July 2007, a mandatory Federal observer program was implemented to characterize the U.S. Gulf of Mexico penaeid shrimp (Farfantepenaeus aztecus, F. duorarum, and Litopenaeus setiferus) fishery. In June 2008, the program expanded to include the South Atlantic penaeid and rock shrimp, Sicyonia spp., fisheries. Data collected from 10,206 tows during 5,197 sea days of observations were analyzed by geographical area and target species. The majority of tows (~70%) sampled were off the coasts of Texas and Louisiana. Based on total hours towed, the highest concentrated effort occurred off South Texas and southwestern Florida. Gear information, such as net characteristics, bycatch reduction devices, and turtle excluder devices were fairly consistent among areas and target species. By species categories, finfish comprised the majority (≥57%) of the catch composition in the Gulf of Mexico and South Atlantic penaeid shrimp fisheries, while in the South Atlantic rock shrimp fishery the largest component (41%) was rock shrimp. Bycatch to shrimp ratios were lower than reported in previous studies for the Gulf of Mexico penaeid shrimp fishery. These decreased ratios may be attributed to several factors, notably decreased shrimp effort and higher shrimp catch per unit of effort (CPUE) in recent years. CPUE density surface plots for several species of interest illustrated spatial differences in distribution. Hot Spot Analyses for shrimp (penaeid and rock) and bycatch species identified areas with significant clustering of high or low CPUE values. Spatial and temporal distribution of protected species interactions were documented.
Resumo:
Temperate reefs are superb tractable systems for testing hypotheses in ecology and evolutionary biology. Accordingly there is a rich history of research stretching back over 100 years, which has made major contributions to general ecological and evolutionary theory as well as providing better understanding of how littoral systems work by linking pattern with process. A brief resumé of the history of temperate reef ecology is provided to celebrate this rich heritage. As a community, temperate reef ecologists generally do well designed experiments and test well formulated hypotheses. Increasingly large datasets are being collected, collated and subjected to complex meta-analyses and used for modelling. These datasets do not happen spontaneously – the burgeoning subject of macroecology is possible only because of the efforts of dedicated natural historians whether it be observing birds, butterflies, or barnacles. High-quality natural history and old-fashioned field craft enable surveys or experiments to be stratified (i.e. replicates are replicates and not a random bit of rock) and lead to the generation of more insightful hypotheses. Modern molecular approaches have led to the discovery of cryptic species and provided phylogeographical insights, but natural history is still required to identify species in the field. We advocate a blend of modern approaches with old school skills and a fondness for temperate reefs in all their splendour.
Resumo:
One of the mechanisms proposed for heating the corona above solar active regions is the damping of magnetohydrodynamic (MHD) waves. Continuing on previous work, we provide observational evidence for the existence of high-frequency MHD waves in coronal loops observed during the August 1999 total solar eclipse. A wavelet analysis is used to identify twenty 4 x 4 arcsec(2) areas showing intensity oscillations. All detections lie in the frequency range 0.15 - 0.25 Hz (7 - 4 s), last for at least 3 periods at a confidence level of more than 99% and arise just outside known coronal loops. This leads us to suggest that they occur in low emission-measure or different temperature loops associated with the active region.
Resumo:
Intense, few-femtosecond pulse technology has enabled studies of the fastest vibrational relaxation processes. The hydrogen group vibrations can be imaged and manipulated using intense infrared pulses. Through numerical simulation, we demonstrate an example of ultrafast coherent control that could be effected with current experimental facilities, and observed using high-resolution time-of-flight spectroscopy. The proposal is a pump-probe-type technique to manipulate the D2+ ion with ultrashort pulse sequences. The simulations presented show that vibrational selection can be achieved through pulse delay. We find that the vibrational system can be purified to a two-level system thus realizing a vibrational qubit. A novel scheme for the selective transfer of population between these two levels, based on a Raman process and conditioned upon the delay time of a second control-pulse is outlined, and may enable quantum encoding with this system.
Resumo:
Research Question: A20 is an LPS-inducible, cytoplasmic zinc finger protein, that inhibits TLR-activated NF-?B signalling by deubiquitinating TRAF6. A20 action is facilitated by complex formation with RNF11, Itch and TAX1BP1. This study investigates if the expression of A20 is altered in the chronically inflamed Cystic Fibrosis (CF) airway epithelium.
Methods: Nasal epithelial cells from CF patients (F508del homozygous), non-CF controls and immortalised epithelial cells (16HBE14o- and CFBE41o-) were stimulated with LPS. Cytoplasmic expression of A20 and expression of NF-?B subunits was analysed. Formation of the A20 ubiquitin editing complex was also investigated.
Results: In CFBE41o-, peak LPS-induced A20 expression was delayed compared with 16HBE14o- and fell significantly below basal levels 12-24 h after LPS stimulation. This was confirmed in primary CF airway cells. Additionally, a significant inverse relationship between A20 and p65 expression was observed. Inhibitor studies showed that A20 does not undergo proteasomal degradation in CFBE41o-. A20 interacted with TAX1BP1, RNF11 and TRAF6 in 16HBE14o- cells, but these interactions were not observed in CFBE41o-.
Conclusion: he expression of A20 is significantly altered in CF and important interactions with complex members and target proteins are lost, which may contribute to the state of chronic NF-?B-driven inflammation.
Resumo:
Abstract: Background: A20 and TAX1BP1 interact to negatively regulate NF-
-driven inflammation. A20 expression is altered in F508del/F508del
patients. Here we explore the effect of CFTR and CFTR genotype on A20 and
TAX1BP1expression. The relationship with lung function is also assessed.
Methods: Primary Nasal Epithelial cells (NECs) from CF patients
(F508del/F508del, n=8, R117H/F508del, n=6) and Controls (age-matched,
n=8), and 16HBE14o- cells were investigated. A20 and TAX1BP1 gene
expression was determined by qPCR.
Results: Silencing of CFTR reduced basal A20 expression. Following LPS
stimulation A20 and TAX1BP1 expression was induced in control NECs and
reduced in CF NECs, broadly reflecting the CF genotype: F508del/F508del
had lower expression than R117H/F508del. A20, but not TAX1BP1 expression,
was proportional to FEV1 in all CF patients (r=0.968, p<0.001).
Conclusions: A20 expression is reduced in CF and is proportional to FEV1.
Pending confirmation in a larger study, A20 may prove a novel predictor
of CF inflammation/disease severity.