Influences of oxygen partial pressure on structure and related properties of ZrO2 thin films prepared by electron beam evaporation deposition

ZrO2 thin films were prepared by electron beam evaporation at different oxygen partial pressures. The influences of oxygen partial pressure on structure and related properties of ZrO2 thin films were studied. Transmittance, thermal absorption, structure and residual stress of ZrO2 thin films were measured by spectrophotometer, surface thermal lensing technique (STL), X-ray diffraction and optical interferometer, respectively. The results showed that the structure and related properties varied progressively with the increase of oxygen partial pressure. The refractive indices and the packing densities of the thin films decreased when the oxygen partial pressure increased. The tetragonal phase fraction in the thin films decreased gradually as oxygen partial pressure increased. The residual stress of film deposited at base pressure was high compressive stress, the value decreased with the increase of oxygen partial pressure, and the residual stress became tensile with the further increase of oxygen pressure, which was corresponding to the evolution of packing densities and variation of interplanar distances. (c) 2007 Elsevier B.V. All rights reserved.

Influences of CO2 laser annealing on mechanical and laser-induced damage properties of ZrO2 thin films

Zirconium dioxide (ZrO2) thin films were deposited on BK7 glass substrates by the electron beam evaporation method. A continuous wave CO2 laser was used to anneal the ZrO2 thin films to investigate whether beneficial changes could be produced. After annealing at different laser scanning speeds by CO2 laser, weak absorption of the coatings was measured by the surface thermal lensing (STL) technique, and then laser-induced damage threshold (LIDT) was also determined. It was found that the weak absorption decreased first, while the laser scanning speed is below some value, then increased. The LIDT of the ZrO2 coatings decreased greatly when the laser scanning speeds were below some value. A Nomarski microscope was employed to map the damage morphology, and it was found that the damage behavior was defect-initiated both for annealed and as-deposited samples. The influences of post-deposition CO2 laser annealing on the structural and mechanical properties of the films have also been investigated by X-ray diffraction and ZYGO interferometer. It was found that the microstructure of the ZrO2 films did not change. The residual stress in ZrO2 films showed a tendency from tensile to compressive after CO, laser annealing, and the variation quantity of the residual stress increased with decreasing laser scanning speed. The residual stress may be mitigated to some extent at proper treatment parameters. (c) 2007 Elsevier GmbH. All rights reserved.

Use of telemetric tracking to examine environmental influences on catch/effort indices. A case study of Atlantic Salmon (Salmo salar L.)in the R. Tywi, S. Wales

A case study of Atlantic Salmon runs into the R. Tyvi (S. Wales) is presented. Radio tracking of over 200 salmon in 1988 and 1989 has demonstrated that flow is an important factor in modifying both run timing and migratory success. Entry of salmon into the river is typically in response to flow events, and periods of low falling flows delay entry and may directly result in reduced runs into the river. Delayed entry may also increase the proportion of the run migrating after the end of both rod and net fishing seasons. The implications of these results for net and rod catch and catch/effort data are discussed, using both statutory reported catch data and data from specific catch/effort studies. Flow is demonstrated to be a dominant factor in determining the within-season distribution of rod catch and catch/effort during low-flow years. Estuarial seine net catch and catch/effort tend to be controlled more by time of return than by flow although low flows may delay runs. Annual reported rod catch is correlated with flow, which controls in season availability, catchability and consequently the amount of fishing effort. Use of catch or catch/effort data should take account of inter-year variations in flow and other environmental factors. Although catch and catch/effort are valuable indicators of fishery performance, they are inadequate to represent changing stock levels.

Meteorological influences on North America quail populations [abstract, table, and figure]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Comparative study of environmental influences on the population dynamics of three North American species of quail, California quail (Callipepla california), Gambel's quail (C. gambellii), and scaled quail (C. squamata) has lead to identification of differential sensitivity of these species to global weather patterns.

Temporal trends (2000–2011) and influences on fishery-independent catch rates for loggerhead sea turtles (Caretta caretta) at an important coastal foraging region in the southeastern United States

Seasonal trawling was conducted randomly in coastal (depths of 4.6–17 m) waters from St. Augustine, Florida, (29.9°N) to Winyah Bay, South Carolina (33.1°N), during 2000–03, 2008–09, and 2011 to assess annual trends in the relative abundance of sea turtles. A total of 1262 loggerhead sea turtles (Caretta caretta) were captured in 23% (951) of 4207 sampling events. Capture rates (overall and among prevalent 5-cm size classes) were analyzed through the use of a generalized linear model with log link function for the 4097 events that had complete observations for all 25 model parameters. Final models explained 6.6% (70.1–75.0 cm minimum straight-line carapace length [SCLmin]) to 14.9% (75.1–80.0 cm SCLmin) of deviance in the data set. Sampling year, geographic subregion, and distance from shore were retained as significant terms in all final models, and these terms collectively accounted for 6.2% of overall model deviance (range: 4.5–11.7% of variance among 5-cm size classes). We retained 18 parameters only in a subset of final models: 4 as exclusively significant terms, 5 as a mixture of significant or nonsignificant terms, and 9 as exclusively nonsignificant terms. Four parameters also were dropped completely from all final models. The generalized linear model proved appropriate for monitoring trends for this data set that was laden with zero values for catches and was compiled for a globally protected species. Because we could not account for much model deviance, metrics other than those examined in our study may better explain catch variability and, once elucidated, their inclusion in the generalized linear model should improve model fits.

ENSO influences on atmospheric circulation and precipitation in the western United States

EXTRACT (SEE PDF FOR FULL ABSTRACT): The influence of ENSO on atmospheric circulation and precipitation over the western United States is presented from two perspectives. First, ENSO-associated circulation patterns over the North Pacific/North America sector were identified using an REOF (rotated empirical orthogonal function) analysis of the 700-mb height field and compositing these for extreme phases of the Southern Oscillation Index. ... Second, we examine the variability of precipitation during the warm and cool phases of ENSO for different locations in the western United States.

Determining the role of linear and nonlinear interactions in records of climate change: possible solar influences in annual to century-scale records

Time series analysis methods have traditionally helped in identifying the role of various forcing mechanisms in influencing climate change. A challenge to understanding decadal and century-scale climate change has been that the linkages between climate changes and potential forcing mechanisms such as solar variability are often uncertain. However, most studies have focused on the role of climate forcing and climate response within a strictly linear framework. Nonlinear time series analysis procedures provide the opportunity to analyze the role of climate forcing and climate responses between different time scales of climate change. An example is provided by the possible nonlinear response of paleo-ENSO-scale climate changes as identified from coral records to forcing by the solar cycle at longer time scales.

Chronic and catastrophic influences of the environment on the population dynamics of the common fishes [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Seasonal, interannual, decadal and centennial influences on population dynamics have been described for several species. It now seems possible to interpret environmental changes that initiate population change ...

Socio-cultural influences on sanitation, fish handling and artisanal fish processing within the fishing communities

The fishery sector in Uganda has seen important changes in the last two decades. Among the changes registered, is the expansion of fish markets locally, regionally and internationally. Upon which, remarkable benefits have been realized at local and national levels, for instance, it is estimated that an average of 40m$ is being earned annually as foreign exchange. Besides, presently fish accounts for over 50% of total animal protein in take. However, it is argued that sustaining these gains has become an up hill task due to failure to maintain fish quality as a result of the rudimentary and inappropriate sanitary, fish handling and artisanal fish processing practices that both directly and indirectly affect the quality of fish and fish products. Therefore, against this background, a study of 507 respondents was undertaken among the Lake Victoria Communities specifically in Wakiso, Mayuge and Mukono districts. The study examined the perceptions of fishers on the social cultural practices of sanitation, fish handling and artisanal fish processing and consequently identified factors that influenced these practices.