Chi recombination activity in phage lambda decays as a function of genetic distance

In Escherichia coli, chi is a recombination hotspot that stimulates RecBCD-dependent exchange at and to one side of itself. chi activity is highest at chi and decreases with distance from chi. The decrease in chi activity may be a simple property of the physical distance over which chi can stimulate recombination. Alternatively, the decay in chi activity with distance may reflect the high likelihood that chi-stimulated recombination occurs in a single chi-proximal act, to the exclusion of additional chi-stimulated exchanges more distal to chi. To test the models, we determined if chi activity decreases as a function of physical distance (i.e., DNA base pairs) or genetic distance (homologous DNA base pairs). Our results indicate that chi activity decays as a function of genetic distance. In addition, we found that the sbcB gene product (exonuclease I, a 3'-->5' ssDNA exonuclease) modulates the distance over which chi can act. In contrast, the recJ gene product (a 5'-->3' ssDNA exonuclease) does not alter the decay of chi activity.     

Chiasma frequency, distribution and interference maps of mouse autosomes

Chiasma frequencies were analysed and chiasma positions measured in diakinesis/metaphase I autosomal bivalents from oocytes and spermatocytes of F1 hybrid C3H/HeHx101/H mice. Twenty chromosome size ranks, including the presumptive X bivalent, could be distinguished in oocytes, and nineteen autosomal ranks plus the XY pair spermatocytes. Overall, mean cell chiasma frequencies of the two sexes did not differ significantly once the contribution of the presumptive X bivalent and the XY pair were taken into account. Sex related differences in chiasma distribution patterns were evident, however. In monochiasmate bivalents, the chiasma was most commonly located interstitially in oocytes while in spermatocytes it could be either interstitial or distal. In dichiasmate bivalents, the chiasmata tended to be more centrally located in oocytes than in spermatocytes. Minimum inter-chiasma distances did not appear to show any great variation in chromosome pairs of different sizes, however, mean inter-chiasma distances did increase with the bivalent length. The minimum-inter chiasma distance data suggest that chiasma interference is complete over a chromosomal segment equating to approximately 60Mb. Measurement of the positions of chiasmata along chromosome arms open up the possibility of producing chiasma-based genetic maps for all the autosomes of the mouse.     

Resistance to cognitive interference as a function of MMPI profile.

Scored undergraduates for resistance to interference according to their results on the Stroop Color-Word Test and then classified the Ss into 3 groups on the basis of their MMPI profiles. Results of analyses support the hypothesis that resistance to interference, as measured by the Stroop Test, is related to psychopathology and indicate that behavioral tests can be of use to the clinician in understanding and predicting behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Degrees of client comfort as a function of dyadic interaction distance.

27 male undergraduates were interviewed by 9 male counseling students using an intake interview. Each student counselor saw 3 Ss, one in each of 3 counselor-client distance conditions: 18, 30, and 48 in. An analysis of variance revealed significant differences between conditions in the degree of comfort reported by Ss on evaluative scales of a posttest semantic differential. As a further indicator of Ss' degree of comfort, the semantic differential scales were compared to observers' ratings on a behavior checklist and found to have a positive correlation. Ss' degree of comfort scores ranged from highest for 30 in to lowest for 18 in, with intermediate scores at 48 in. Results suggest that degree of client comfort is optimized at specific interaction distances during an intake interview. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Radar target detection as a function of search area and viewing distance.

The detection task employed a 9?-in. plan position indicator (PPI) and simulated targets. 30 Army trainees served as Ss. Each S performed the 9 combinations of viewing distance, (a) 6 ins., (b) 12 ins., (c) 18 ins., and, search area, (a) whole scope, (b) ? scope, and (c) –1–1??-diameter circle within the whole scope. A Treatments X Treatments X Subjects analysis of variance indicated significant main and interaction effects: as viewing distance increases, detection performance is degraded; as search area increases, detection performance is degraded; optimum viewing distance when searching the whole scope is approximately 12 ins., while optimum viewing distance for a small area (–1–1??-in. diameter) within a larger area is 6 ins. or less. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fixation disparity and accommodation as a function of viewing distance and prism load

Fixation disparity was measured with dichoptically presented nonius lines at viewing distances of 20, 30, 40, 60, and 100 cm, so that both vergence and accommodation were stimulated adequately as in normal vision. As the viewing distance was shortened, mean fixation disparity changed monotonically from 1 min arc eso (i.e., the eyes converged in front of the target) to 3 min arc exo. The average standard deviation of the psychometric function of fixation disparity, which is a measure of the temporal variability of vergence, was smallest at 100 cm (when fixation disparity was eso) and increased as viewing distance decreased. Fixation disparity itself and the change of fixation disparity with distance differed reliably among subjects with normal binocular vision, but neither was related to the momentary degree of accommodation. Fixation disparity was also measured at a constant distance of 40 cm, but with prisms in front of the eyes that induced the same vergence angles as viewing distances between 20 and 100 cm. The slope of these conventional fixation disparity curves as a function of prism load was generally larger than the slope of fixation disparity as a function of viewing distance (which can be explained by accommodative vergence), but the slopes of the two types of curves were correlated (r = 0.39, P = 0.02, n = 25).     

Associative interference in schizophrenia as a function of paranoid status and premorbid adjustment.

Administered a sorting task and a paired-associates-learning task, which included a built-in associative interference factor, to 80 hospitalized white male chronic schizophrenics, divided by paranoid or nonparanoid status and good or poor premorbid adjustment, and matched for age and education. Results added support to the associative interference theory concerning psychological deficit in schizophrenia. This was more pronounced in the case of the sorting task than the paired-associates-learning task perhaps because the latter is confounded by a strong memory factor. Findings also indicate that paranoid and premorbid status interactively affect performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in schizophrenia: Associative interference and facilitation as a function of visual context.

Irrelevant stimuli that flank a fixated target may cause either facilitation or interference with target classification. 20 schizophrenic patients, 20 depressed control patients, and 20 normal control Ss were compared on a flanker priming task that involved the linear display of a target surrounded by 2 flanking letters or digits. Choice reaction time (RT) between letter and digit targets was examined as a function of flanker condition and onset asynchrony between flankers and target. Facilitative priming occurred only with prior exposure of flankers compatible with the response required and was greater in degree with schizophrenic and depressed than with normal Ss. Interference from flankers incompatible with the response required occurred less among schizophrenics than among other groups. Several different processes may be involved in the inhibition of irrelevant information by schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The extinction of fear as a function of distance versus dissimilarity from the original conflict situation.

An earlier study (see 30: 4198) studied the behavior of rats running down alleys in which they had been shocked in comparison to alleys resembling, to various degrees, the original shock alley. Since the least similar alley was always furthest away from the original, alley similarity and distance were confounded. The present investigation was an attempt to correct this confounding. It was shown that the rat's capacity to overcome the inhibitory effects of shock experienced in one alley was related to distance from the original alley, not dissimilarity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Symbolic distance between numerosity and identity modulates Stroop interference

Thirty undergraduates participated in an experiment investigating the effect of the arithmetic difference between stimulus identity and stimulus numerosity in a numerical version of the Stroop task. It was found that digits symbolically close to the enumeration response reliably produced larger interference than digits that were farther from the enumeration response. This semantic distance effect was found with different numerosities (1-9) and different enumeration processes (counting and subitizing), and it increased as a function of numerosity in the subitizing range. These findings suggest that digit identity autonomously activates a magnitude representation organized as a compressed number line.     

Wear resistance of four luting agents as a function of marginal gap distance, cement type, and restorative material

This study investigated the effect of marginal gap width, luting cement, and restorative material on the wear resistance of the luting cement in areas where no occlusal contact is present. Three types of resin luting cement and one resin-modified glass-ionomer cement were used with two inlay systems, a resin composite, and an all-ceramic system. Bovine enamel represented tooth structure. Toothbrush abrasion was the wear modality. Three predetermined gap widths were selected: 240 +/- 30 microns, 150 +/- 30 microns, and 60 +/- 30 microns. All specimens were thermocycled. Regardless of the luting cement or the restorative material, there was a significant difference (P < 0.05) in wear resistance of the cement among the three gap distances at both the enamel and restoration interface. Vertical wear of the luting cement at the enamel interface increased linearly with marginal gap distance when all four cements were considered together (r2 > 0.51), regardless of type of restorative material used. The resin-modified glass-ionomer cement showed the least amount of wear for all variables considered. Significant differences in wear were found between the four luting cements at wide gap distances (240 microns) at the enamel interface, regardless of type of restorative material used. No significant differences were found between the two restorative materials at the enamel interface at the three gap distances.     

Preferred interpersonal distance as a function of locus of control orientation in chronic schizophrenics, nonschizophrenic patients, and normals.

Used a new instrument, the Comfortable Interpersonal Distance scale, to reassess the relationship between psychopathology and interpersonal distance. It was predicted that, since schizophrenics are more external than normals and since externality has been shown to be related to greater preferred distance from others, 20 female schizophrenics theoretically should prefer greater distance, in general, from interpersonal stimuli. 20 female nonschizophrenic patients were included as controls for the "externalizing" effects of hospitalization. Results show that schizophrenics were more external than nonschizophrenics, who were more external than 20 normals. Preferred distance from interpersonal stimuli as measured by the Comfortable Interpersonal Distance scale was greatest for schizophrenics and least for normals. Implications for future research and treatment of schizophrenic patients are discussed. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Height perception: A function of social distance.

Investigated the effects of (a) status-related ethnic membership, and (b) the prejudice of the O on height perception. Ss were 126 undergraduates who were shown slides of various objects and people in a counter-balanced fashion. It was found that height-equated individuals rated high on the Bogardus Social Distance Scale were perceived as taller than height-equated individuals rated low on the Bogardus Social Distance Scale. The implications of these findings are discussed. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Displacement as a function of conflict.

"Miller's theory of displacement was extended by integration with his conflict theory into a three-dimensional model… . To test deductions from this model rats were first trained to get food at one end of an alley and then shocked while eating until they no longer approached the food cup. They then left this alley and entered other alleys differing slightly from the original alley. Here they went closer to the food end than in the original alley. Tracings of their movements followed a pattern predicted from the model… . After making goal responses in the generalized alleys, the rats returned to eat in the original alley, showing a 'therapeutic' effect." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prejudice as a function of self-organization.

This article reviewed the traditional psychoanalytic theories of the development and maintenance of prejudiced attitudes and affects. To this body of understanding, the authors offered a self psychological perspective. They described the treatment of Sandy, a woman who presented with extreme expressions of prejudice, to illustrate how self psychology provides a framework for understanding the narcissistic roots of her prejudice and a therapeutic stance for promoting the transformation of her prejudiced attitudes and affects. From this perspective, prejudice is understood not as the displacement or projection of aggression, but as an expression of a vulnerable, fragmentation-prone self-organization struggling to overcome a traumatic developmental history. (PsycINFO Database Record (c) 2010 APA, all rights reserved)