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Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Variability in performance in wild Atlantic salmon, Salmo salar L., fry from a single redd

FISHERIES MANAGEMENT & ECOLOGY, Issue 6 2000
C. García De Leániz
Dispersal and growth were studied in Atlantic salmon, Salmo salar L., fry from a natural isolated redd. The distribution of fry leaving the redd was strongly peaked, 80% being caught within a 2-week period. Early in the dispersal period, all fry leaving the redd had remnants of yolk sac and had not fed; by half way through the dispersal period, no fry had any visible yolk, but 35% still had empty stomachs. Fry leaving the redd during the first half of the dispersal period tended to settle in different first feeding sites than those dispersing later. Predation on fry by larger salmonids was frequent, especially during dispersal. Coefficients of variation for length, weight and condition factor increased significantly over the study period and for individually recognised fry, growth rates varied markedly. Thus, individual salmon fry differ in physical status on emergence from the redd and these differences are amplified during the first few weeks after emergence. [source]

Assessment of algorithms for the no-slip boundary condition in the lattice Boltzmann equation of BGK model

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2008
Yong Kweon Suh
Abstract Three kinds of algorithms for the lattice Boltzmann equation of the BGK model in the implementation of the no-slip boundary condition on the wall are assessed by using the analytical formula for the slip velocity of the fully developed pressure-driven channel flow. It is shown that the bounce-back algorithm results in the spatial accuracy of 1st order, except for the case when the wall is located at half way between the two grid lines. The interpolation scheme proposed by Yu et al. (Prog. Aerospace Sci. 2003; 39:329,367) and the similar one by Bouzidi et al. (Phys. Fluids 2001; 13(11):3452,3459) are of 2nd order, but the error increases quadratically with the relaxation time. The extrapolation scheme of Guo et al. (Phys. Fluids 2002; 14(6):2007,2010) is also shown to be of 2nd order, and the error level increases linearly with the relaxation time, but it turns out that this scheme is unstable for a certain range of parameter values. Numerical experiments with various parameter sets have been performed to obtain the stability diagram. Three algorithms are then applied to a circular-Couette flow and their performance is also studied in terms of the numerical accuracy and stability. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Convective Available Potential Energy (CAPE) in mixed phase cloud conditions

THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 624 2007
B. Früh
Abstract An approximate but pragmatic approach is presented to define Convective Available Potential Energy (CAPE) in mixed phase cloud conditions. The underlying process calls for mixed (i.e. liquid and ice) phase parcels and assumes the liquid fraction to be a unique function of temperature. The approach is meant to represent average conditions. Differences between this and more traditional approaches are quantified and discussed for mean tropical conditions. Generally freezing increases parcel temperature and, hence, buoyancy. If freezing occurs isobarically (as was often assumed in the past), all water changes phase at a single level resulting in a discontinuity in buoyancy at that level. By contrast, the mixed phase parcel process implies a continuous phase transition in a finite range of temperatures Tfs , T , Tfe, leading to a gradual change of buoyancy with altitude and preventing any temperature inversion. The details of this gradual change depend on the choice of the specified temperature range [Tfs, Tfe]. High in the troposphere, where all water is frozen irrespective of the details, the differences between the buoyancy profiles are small (but finite). CAPE is very sensitive to the treatment of the freezing process. Isobaric freezing at a relatively high temperature (e.g. , 5 °C) in a reversible process may increase CAPE by a factor of 2 to 3, and this increase is similar in magnitude to the difference between the pseudo-adiabatic and the reversible processes for pure water parcels. Both of these processes are considered less realistic than the reversible mixed phase process with continuous freezing over a broad temperature range [Tfs, Tfe] = [,5 °C, , 40 °C]; the corresponding CAPE lies about half way between the reversible and irreversible pure water processes. For clouds with finite precipitation efficiency the effect of freezing is less pronounced than for reversible conditions. Copyright © 2007 Royal Meteorological Society [source]

Prospective evaluation of cognitive function in patients with early breast cancer receiving adjuvant chemotherapy

ASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 3 2007
Michelle RUZICH
Abstract Aim: To assess cognitive function prospectively in women with early breast cancer before, during and after the administration of adjuvant chemotherapy. Methods: Between May 2000 and November 2001, 35 assessable patients were entered into the study. Thirty-one received oral cyclophosphamide, methotrexate and 5-fluorouracil (CMF) and four received epirubicin and cyclophosphamide followed by CMF ((cyclophosphamide, methotrexate and 5-fluorouracil)). Testing consisted of the completion of a battery of neuropsychological and psychological inventories and was performed prior to chemotherapy and repeated after 3 (n = 31) and 6 months (n = 30) of chemotherapy and also 6 months after the completion of chemotherapy (n = 27). Results: Prior to chemotherapy a proportion of the patients already exhibited some evidence of impairment of cognitive function. However, on completion of chemotherapy, the neuropsychological scores for short-term verbal memory and verbal learning were significantly lower than prior to, or 6 months after chemotherapy. In all other domains, cognitive function either remained constant or even appeared to improve. Symptom scales showed that fatigue, nausea and vomiting, constipation and diarrhea were worst half way through the chemotherapy. Quality of life scales indicated that functioning was best after completion of chemotherapy. Conclusion: Patients with early breast cancer may have impaired cognitive function before chemotherapy. Although transient deteriorations in verbal memory and verbal learning were observed on completion of chemotherapy, overall, cognitive function did not decline. It is likely that practice effects influenced our findings. [source]