Regional differences in collagen stable isotope and tissue trace element profiles in populations of long-tailed duck breeding in the Canadian Arctic

Adult long-tailed ducks (Clangula hyemalis) were collected from nine locations across their breeding grounds in northern Canada and measurements of stable isotopes of carbon (delta(13)C), nitrogen (delta(15)N) and sulfur (delta(34)S) in bone collagen were used to investigate if relative use of freshwater habitats such as the Great Lakes (with expected depleted stable isotope profiles) compared with coastal marine environments (with expected enriched stable isotope foodweb profiles) could explain tissue trace element profiles. Contrary to expectation, all three stable isotopes did not covary in our sample, suggesting that mechanisms other than simple freshwater vs. marine isotopic gradients were involved among populations. All three stable isotopes varied significantly with collection location and both delta(15)N and delta(13)C values varied significantly between sexes suggesting that males exploit either a different food base or occur in different geographic areas than females for at least part of the year. The delta(34)S data, in particular, suggested that many of the birds breeding in the western Canadian Arctic probably overwinter in the Great Lakes along with many of the birds breeding in Hudson Bay. Males at the majority of collection locations had higher concentrations of hepatic Hg (1.1-8 microg/g dw), Cu (25-40 mug/g dw), Se (7.3-27 mug/g dw) and renal Cd (33-129 microg/g dw) than females. Concentrations of Hg, Cu and Cd were well below toxicological threshold levels found in the literature. However, hepatic Se concentrations in 64% of the females exceeded 10 mug/g dw and concentrations in 8% of the birds measured exceeded 33 microg/g dw suggesting levels of potential concern.     

Magnetic resonance imaging and quantitative analysis of particle deposition in porous media

Measurements of particle deposition and mobilization in water-saturated porous columns were performed using nuclear magnetic resonance imaging (MRI). The use of MRI enabled the acquisition of detailed, noninvasive measurements that quantify spatial and temporal evolution of particle transport patterns and porosity changes due to particle deposition. Measurements indicate that for the considered particle sizes and flow conditions significant particle deposition occurs at some distance into the column. Because identification of unique parametrizations for processes of particle straining, deposition, and detachment is complex and nonunique, a simple phenomenological model of particle deposition and porosity reduction is suggested. This model captures the essential features of the experimental measurements on spatial and temporal flow and deposition patterns.     

Characteristics of impala (Aepyceros melampus) skeletal muscles

The aim of this study was to determine citrate synthase (CS), phosphofructokinase (PFK) activities and myosin heavy chain (MHC) isoform contents in four muscle groups (semimembranosus (S), deltoideus (D), longissimus lumborum (LL), and psoas major (PM)) of impala (n=6). All four muscle groups expressed predominantly MHC IIa (means of 55±22-93±12%). MHC IIx was only expressed in D. In D, positive correlations were found between MHC I and age (r=0.93; P<0.05) and the weight of the animals (r=0.94; P<0.01). PFK (means of 175±179-374±181), CS (means of 100±23-126±38 μmol/min/gdw) and MHC content indicated that energy provision in the impala is produced to a large extent via oxidative pathways and fibre types vary with animal characteristics.     

Numerical stability of the classical and the modified Saul'yev's finite-difference methods

Stability criteria a modified Saul'yev's explicit method for parabolic partial differential equations are derived and compared with those of classical Saul'yev's explicit method and Crank-Nicholson's implicit method. The two Saul'yev methods operated in the averaging mode are found to be unconditionally stable with respect to the heat equation. However, when lower order terms are included in the linear test equation, the modified method is shown to have a greater stability region than the classical method, while the Crank-Nicholson method maintains its stability unconditionally. Results of numerical experiments confirm the validity of the derived criteria.     

Spray pyrolysis of CuInSe2 and related ternary semiconducting compounds

CuInSe₂ and related compounds and alloys, which are promising for solar cell applications, were produced in thin polycrystalline sphalerite structure layers by spray pyrolysis in both p- and n-type forms with various resistivities. Complete sphalerite structure solid solution is indicated for the entire four-component system CuGaS₂-CuInS₂-CuInSe₂-CuGaSe₂ which suggests the possibility of tailoring properties such as lattice parameter, energy gap and conductivity type to produce heterojunctions suitable for low cost solar cells by spray pyrolysis.     

Utility of merit increases.

Utilized a magnitude estimation technique to determine the relationship between merit increases and satisfaction for 157 professional employees of an electronics organization. The linear, logarithmic, and power functions were fitted to the data in combination with 4 frames of reference. The power function and the percentage of perceived equitable merit increase frame of reference gave the best fit to the data. The Bernoullian concept of diminishing utility for each added dollar was not supported. Analyses found that each dollar of merit increase had increased utility. For approximately 10% of the sample, satisfaction was not a monotonic increasing function of dollars. This is contrary to accepted economic theory but is consistent with equity theory. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychosocial factors affecting the employment of former vocational rehabilitation clients.

Analyzed questionnaires completed by 211 former vocational rehabilitation (VR) clients (aged 15–61 yrs) 2 yrs after case closure for a clarification of the psychosocial factors that affect vocational adjustment. Questionnaires assessed employment status and problems, sources of income/financial status, health, and job satisfaction (for employed Ss only). WAIS Full Scale IQs were available for 195 Ss, and 120 Ss had completed the 16PF—Form E. Results show that the primary criteria of vocational adjustment (employment, job satisfaction, and persistence in looking for work) were associated with better self-appraised physical and mental health, greater perceived family support in seeking employment, more optimism about employment prospects, and attribution of the problem source to the environment. These variables suggest useful points for intervention by VR practitioners. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Keeping people well despite life change crises

IgE was found in urine from healthy adult volunteers at very low levels (approximately 0.003-0.010 IU/ml), corresponding to a 24-h excrection rate of 3-16 IU. IgE was not detected in 36 out of 47 samples of milk and colostrum. In samples from six women the protein was present at low concentration 1-2 days postpartum but was not detected in later samples (usually day 5 or 6). Mammary secretions from four allergic donors were studied, and IgE was detected at low concentrations in samples from the two most severely affected individuals. The levels of IgE observed in both urine and milk suggest that there is no significant synthesis of the protein in either the urinary tract or in mammary tissue.     

Short communication. Improving overlay handlers

Code overlay segments are commonly used to implement large program modules on machines with limited address space. Unfortunately, these systems usually impose some limitations on the permissible sequence of subroutine invocations. This paper discusses the reasons for these limitations and introduces a simple change that allows more general invocation sequences to be used.