Small sample profile analysis with many variables.

Monte Carlo methods were used to investigate the adequacy of 2 approaches to data analysis in a repeated measures design in which the number of repeated levels was large and the sample size was relatively small. The techniques examined were G. E. Box's (1954) ε?-adjustment and H. Huynh and L. S. Feldt's (1976) ε?-adjustment. Results show that approximate univariate approaches to repeated measures can successfully be used even when the number of Ss is smaller than the number of levels of the repeated factor. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunohistochemical staining of ovarian granulosa cell tumors with monoclonal antibody against inhibin

Inhibin is a peptide hormone produced by ovarian granulosa cells and by granulosa cell tumors. Serum inhibin measurements have been used as a biochemical marker of the presence or progression of ovarian granulosa cell tumors and their metastases. In the current study, an antibody against the alpha-subunit of human inhibin was used to stain 16 cases of ovarian adult granulosa cell tumors, 15 cases of other ovarian sex cord-stromal tumors, and 51 cases of a range of ovarian and extraovarian neoplasms, many of which may mimic granulosa cell tumor. There was diffuse strong cytoplasmic staining of all cases of adult granulosa cell tumor. Diffuse positive staining also was observed in all Leydig cell tumors, and there was focal staining in a proportion of fibrothecomas. There was focal weak staining of one case of ovarian clear cell carcinoma but no staining of other ovarian and extraovarian neoplasms. Immunohistochemical staining with antibodies against inhibin is of value in the diagnosis of granulosa cell tumor and in the distinction of this neoplasm from others that may mimic it. The antibody also may be useful for the confirmation of late metastasis of granulosa cell tumor, especially when the previous history is not known.     

L-ascorbyl-2-polyphosphate as a vitamin C source for segregated and conventionally weaned pigs

We conducted two experiments to evaluate the efficacy of a stable source of vitamin C for improving performance and iron status in early-weaned pigs. A preparation of L-ascorbyl-2-polyphosphate (Rovimix Stay-C 25, Roche Vitamins, Ames, IA and Bramus, NJ), which supplies 25% ascorbic acid activity in a stable form, served as the vitamin C source and was incorporated at dietary vitamin C levels of 0, 75, or 150 ppm. In Exp. 1, 72 pigs (14 +/- 2 d of age and 4.98 kg BW) were blocked based on initial BW and penned in groups of three (eight pens per treatment) in an off-site nursery for 42 d. Phase 1 lasted from d 0 to 14, Phase 2 from d 14 to 28, and Phase 3 from d 28 to 42 after weaning. Daily gain and gain:feed ratio (G/F) increased during Phase 1 (quadratic, P < .1 and P < .05, respectively), Phase 3 (linear, P < .1 and P < .01, respectively), and for the overall 42-d experiment (linear, P < .05 and P < .1, respectively) in response to increasing dietary vitamin C. At 14 d after weaning, plasma vitamin C increased (linear, P < .05) with increasing dietary vitamin C, but plasma iron, hemoglobin, and hematocrit were not influenced by dietary vitamin C. In Exp. 2, 120 pigs (20 +/- 3 d of age and 7.2 kg BW) were blocked based on initial BW and penned in groups of five (eight pens per treatment) in a conventional nursery system for 31 d. Phase 1 consisted of d 0 to 7, Phase 2 from d 7 to 17, and Phase 3 from d 17 to 31 after weaning. During the period from d 0 to 17 after weaning, ADG and G/F were improved (linear, P < .1) with increasing dietary vitamin C. At d 17 after weaning, plasma vitamin C and serum iron increased (linear, P < .05), but unbound iron-binding capacity and total iron-binding capacity decreased (linear, P < .05 and P < .1, respectively) with increasing dietary vitamin C. These results suggest that dietary vitamin C is needed during the first 42 d after weaning when pigs are weaned as early as 12 d of age and reared in an off-site nursery and during the first 17 d after weaning when pigs are weaned as early as 17 d of age and reared in a conventional nursery system. L-Ascorbyl-2-polyphosphate at a supplemental level of 75 ppm was adequate to meet the dietary vitamin C requirement of early-weaned pigs. Vitamin C supplementation with a stable product will improve performance in young pigs during the high-stress postweaning period and may be particularly beneficial to pigs weaned at a very early age.     

Role of cyclic electron transport in photosynthesis as measured by the photoinduced turnover of P700 in vivo

The light-induced turnover of P700 was measured spectrophotometrically in a wide variety of algae and some photosynthetic mutants. Analysis of the postillumination recovery of P700+ revealed that the apparent first-order rate constant for reduction via the cyclic pathway was much lower that that via the noncyclic pathway. After activation of photosystems 1 and 2 the half-time for reduction of P700+ was 5-20 ms, whereas after activation of primarily photosystem 1 a longer half-time of ca. 150 ms was observed. The extent of the photooxidation of P700 was the same in both regimes of illumination. The longer half-time was also noted after inhibition of photosystem 2 by 3-(3,4-dichlorophenyl)-1,1-dimethylurea or mild heat shock and in mutant algae known to lack a functional photosystem 2. No signal was observed in mutants lacking P700 itself but those strains lacking either plastocyanin or cytochrome f were capable of a very slow turnover (reduction t 1/2 greater than 500 ms at room temperature). This very slow turnover was not affected by carbonyl cyanide m-chlorophenylhydrazone or the plastoquinone antagonist, 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, indicating that the pathway for reduction of P700+ in these mutants is not energy linked and does not utilize the intersystem electron transport chain. The slow, 150 ms, reduction of P700+ due to cyclic flow was not observed when cells were engaged in photosynthesis at high-light intensities. The data are interpreted as evidence for the involvement of the total functional pool of P700 in both electron transport pathways, and we suggest that cyclic electron transport does not contribute to photosynthesis in oxygen-evolving autotrophs.     

Particle size dependence in high gradient magnetic separation

The performance has been studied of a high gradient magnetic separator with well defined physical and geometrical properties on a slurry of particles which could also be well defined in terms of size distribution, susceptibility, and density. A special high gradient magnetic separator was constructed whose matrix was a three-dimensional array of parallel stainless steel wires. A slurry of particles of known susceptibility and density was used. The particle size distributions for both the feed slurry and the captured and noncaptured products were determined. By means of an analysis using dimensionless groups, it was found that the particle recovery plotted against the appropriate dimensionless ratio defined a universal curve such that, at a fixed flow velocity, experimental data points corresponding to a wide range of particle sizes and magnetic fields all fell close to this curve. Data points for two different flow velocities defined separate curves. The probable reason for this is that the particle shapes are irregular, and consquently, the fluid drag coefficients which enter into the dimensionless ratio are unknown and were approximated by the coefficients for spheres of equivalent size.     

Correlation between student satisfaction and grades: A case of mistaken causation?

The correlation between grades of instruction and student satisfaction has been interpreted as providing support for a grading leniency bias model; that is, easy graders receive better evaluations than hard graders because they are easy graders. Two alternative models that explain the correlation of grades with satisfaction are delineated. A student characteristics model (student motivation) is contrasted with the grading leniency bias model in 2 studies. Study 1 considered between-class relationships among grades, satisfaction, performance, and student motivation for the IDEA (Instructional Development and Effectiveness Assessment System) data from several thousand college and university classes across the US. Study 2 considered within-class relationships among grades, satisfaction, performance, and motivation for 19 large university classes. Both studies demonstrate that the relationship between grades and student satisfaction might be viewed as a welcome result of important causal relationships among other variables rather than simply as evidence of contamination due to grading leniency. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Construct validity of measures of college teaching effectiveness.

Compared evaluation form, student, colleague, trained observer, former student, and self-rating teacher assessments of 43 university instructors. Data show that student and former student ratings displayed substantially greater validity coefficients of teaching effectiveness than self-report, colleague, and trained observer ratings. Advantages of student rating techniques (i.e., greater exposure to instructor's teaching), various teaching assessment methods, and problems in the literature due to limitations of research approaches typically used are discussed. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multivariate statistics for family psychology research.

The application of selected multivariate statistics is illustrated for use in family psychology research. The use of multivariate analysis of variance (MANOVA) and discriminant analysis in factorial designs and profile analysis is discussed. Profile analysis provides a method for dealing with unit of analysis issues in family psychology research. Applications of confirmatory factor analysis are also discussed as useful methods for researchers examining multiple components of families and handling multiple perspectives of various family members. Limitations and applications of these methods in family psychology research are reviewed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)