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Monovision has been a controversial contact lens correction modality for over 30 years. This paper addresses the major issues and concerns and considers them in the light of patient safety, visual efficiency and practitioner liability.
It has recently been shown that the consistency of food significantly affects levels of bone strain in the mandible during mastication (Hylander, '79a). Mandibular bone histology was examined to test the effects of a diet of hard food compared to a diet of soft food in two groups of monkeys. One group of rhesus macaques (Macaca mulatta) was fed a diet of commercially prepared hard biscuits. The second group was fed a soft diet the consistency of fudge. Both diets were nutritionally adequate for normal growth and development. As a control for other factors influencing cortical bone structure, fibular morphology was also examined. At the end of the test period, mandibular and fibular tissue samples from the two groups were prepared to determine the amount of secondary Haversian bone present. Mandibular depth at M2 and fibular anteroposterior diameter were also measured and compared between the two dietary groups. The soft-diet monkeys showed low levels of remodeling in their mandibles. There were large patches of unremodeled bone and resorption spaces were common. The hard-diet monkeys exhibited more extensive evidence of secondary Haversian remodeling in their mandibles. The hard-diet monkeys also had deeper mandibles. In contrast, the fibulae from the two groups had similar mean diameters and showed comparable levels of secondary remodeling. We infer that the higher mandibular bone remodeling levels in the hard-diet monkeys represent an adaptive response to remove and replace fatigued mandibular bone due to higher stress levels associated with the ingestion and mastication of hard foods. We also infer that greater depth of the mandible at M2 found in the hard-diet group represents an adaptive response to higher stress levels associated with the ingestion and mastication of hard foods.
The purpose of this study was to analyze the practical knowledge of expert sailing coaches of the French team preparing for the 1996 Olympic Games in Atlanta. Coaching knowledge was studied from a cognitive ergonomics perspective based on the task activity model. According to this model, a task is a set of constraints facing individuals. To meet the demands imposed by these constraints, an individual engages in an adaptative activity which can be studied from the point of view of his or her knowledge and cognitive operating modes. In-depth interviews were conducted after observation of five training sessions, and the verbal protocols obtained were coded inductively. The results showed that coaching tasks were considered by coaches as a set of interacting constraints which generate complex, contradictory, and ill defined problems. Coaches' operating modes appeared to be based on organization routines, cognitive anticipation on flexible plans, flexible on-site adaptation, joint control of training with athletes, and involvement in the training situation based on past experiences.
House fires are the most common disasters in our society. Disaster theorists acknowledge that complex daily living problems impede the recovery of victims. However, these problems have not been described in detail. The author conducted a qualitative study of the disruption to daily living routines caused by house fires and of the adaptation process victims undertook to reestablish effective patterns of purposeful activity. The data-gathering methods included observation on the scenes of 15 house or tenement fires and in-depth interviews with members of 10 families displaced by fires. Disruption was found to occur in the victims' use of time and comfort in their personal environment. A data analysis revealed a new process of occupational adaptation. The roles of tasks and activities were determined to be important in recovery.
PURPOSE: This study was conducted to develop and to test the effects of an educational program for coping with problem situations as a nursing intervention in the diabetic patient. METHOD: A non-equivalent control group pretest-posttest design was used in this study. Data were collected from January to March, 2002. The subjects of the study consisted of 31 diabetic patients(experimental group: 17 patients, control group: 14 patients). The intervention of an educational program for coping with problem situations was applied to the experimental group for 4 weeks (total 8 hours). Data were collected before the educational program, immediately after and 1 months later and were analyzed with repeated measures ANOVA, t-test, and paired t-test. RESULT: 1. There was a significant difference in self efficacy between the experimental and control groups (F=13.793, p=0.001). 2. There was a significant difference in self care behavior between the experimental and control groups (F=4.583, p=0.041). 3. There was a significant difference in coping behavior of the problem situation between the experimental and control groups (F=62.018, p=0.000). There was a significant difference according to experimental stages (F=4.546, p=0.015) and interaction between education and experimental stages (F=12.039, p=0.000). 4. There was a significant difference in glycemic control between the experimental and control groups (t=-3.112, p=0.004). CONCLUSION: These results support that a diabetic educational program for coping with problem situations is effective in promoting and maintaining self efficacy, self care behavior, problem coping behaviors and in improving glycemic control. Thus this program can be recommended as an effective nursing intervention of in-depth education for diabetic patient.
The choice of a functionally and morphologically faultless concept of occlusion is of primary importance in crown and bridge prosthodontics. Generally speaking we can choose between two concepts:--the concept of harmonious occlusion--the gnathological concept of organic occlusion. A case study was used to illustrate in depth the range of application of these two concepts.
This survey of the psychological literature on Artificial Insemination by Donor (AID) pays particular attention to the secrecy. Studies of couples beforehand do not arrive at criteria for choosing psychologically suitable couples. Follow-up questionnaires are superficial and cannot inform us which couples and what percentage of couples encounter psychological difficulties. Case reports of couples who encountered difficulties are too few to permit generalization and cannot specify AID's role in generating symptoms. A second look at the data suggests that, although overlooked, the secrecy surrounding AID may create psychological difficulties, a view supported by the findings at our clinic. A plea is made with specific recommendations to create an ambience in which openness is possible, and which will allow in-depth research of the psychological aspects of AID.
STATEMENT OF PROBLEM: Because of an imagining principle called active triangulation in the Cerec system, a shadow is cast distal to the illuminated objects. This distal shadow may be enlarged when the occlusal-cervical height of the prepared tooth is increased. Depth data of the shadow are unreliable, so the internal fit of Cerec crowns has been questioned. PURPOSE: This study evaluated the influence of different convergence angles and tooth preparation heights on the internal adaptation of Cerec crowns. MATERIAL AND METHODS: Tooth preparations were made on typodont teeth with different combinations of convergence angles and occlusal-cervical heights: Group I = 20 degrees angle, 6 mm height; Group II = 20 degrees angle, 4 mm height; Group III = 12 degrees angle, 6 mm height; and Group IV = 12 degrees angle, 4 mm height. Ten Cerec crowns were fabricated for each type of tooth preparation. Measurements of the internal fit were performed with the cement space replica technique and an image analysis system. Three-way analysis of variance was used to analyze the differences in cement space with different tooth preparations and the number of times that milling tools were used to prepare the Cerec crowns (P<.05). Multiple comparisons were made to evaluate differences between groups (P<.0083). RESULTS: Cerec crowns with a 12 degrees convergence angle demonstrated the best internal fit (cement space in Groups III and IV = 121 +/- 41 microm and 115 +/- 42 microm, respectively). The difference between the 2 convergence types was within the range of the scanning error (25 microm) produced by the Cerec camera. The number of times that milling tools were used had no significant effect on internal fit (P=.78). Tooth preparation height equal to or shorter than 6 mm occlusal-cervically with both 12 degrees and 20 degrees convergence angles also had no significant effect on internal fit (P>.0083). Cement space at distal walls (185 +/- 28 microm) was the thickest among all axial walls (P=.0001) and was twice as thick as that at the facial (90 +/- 14 microm) and palatal walls (92 +/- 15 microm). CONCLUSION: Within the limitations of this study, there was little difference in the internal fit of Cerec crowns prepared with convergence angles of 12 degrees and 20 degrees. Distal shadows influenced the thickness of the cement spaces, particularly at the distal walls. However, tooth preparations with an occlusal-cervical height not greater than 6 mm did not exaggerate the effect of the distal shadows.
1. A sample of 113 large, myelinated first-order afferent fibers innervating the glabrous skin of the squirrel monkey's hand proved to consist primarily of two basic types. In a sample where the only known source of sampling bias is a greater likelihood to record from larger diameter fibers, 40% of the fibers were rapidly adapting (RA) and 60% were very slowly adapting (VSA). Two units were moderately slowly adapting (MSA), and one had the properties of a Pacinian afferent (Pc). 2. The RA and VSA resemble those in the glabrous skin of other mammalian species in terms of thresholds, receptive-field areas, conduction velocities, and the coding of velocity of mechanical displacement of the skin. Mean instantaneous frequency during ramp stimulation is a power function of ramp velocity for both RA and VSA, with exponents generally less than 1.00. However, ramp discharge patterns differ for RA and VSA. 3. The VSA exhibit a wide range of coefficients of variation (CV) of their interspike-interval distributions, but form a continuous distribution with respect to this statistic. In other respects the VSA are more similar to slowly adapting type I than to slowly adapting type II. They lack spontaneous activity, have restricted receptive fields, and are relatively insensitive to skin stretch. 4. Effects of mechanical stimulus velocity and static indentation depth on static discharge rate were examined in 23 squirrel monkey and 22 raccoon SA units having receptive fields on glabrous skin of the hand. 5. Discharge rate during static indentation is a monotonic, increasing function of identation depth. However, the nature of the best-fitting function (highest r) varies from unit to unit. Using a set of standard conditions (milliseconds 100-500 of static displacements up to 960 mum, following a ramp velocity of 100 mum/ms, interstimulus interval of at least 10 s), the ratio of units for which linear, as opposed to logarithmic, functions provided the best fit was 4:3 for squirrel monkeys and 1:3 for raccoons. Few units had power functions as best fits in either species. Differences between fits for different functions within the same unit, however, were often trivial and insignificant. 6. Response rate during static skin displacement is also strongly influenced by prior stimulus ramp velocity. For at least the first 500 ms, discharge rate is positively related to onset velocity but, in many units, within the first 1 s of static displacement, this relationship reverses itself, and the inverse relationship may persist for at least 5 s.
How much of the variation in adaptive divergence can be explained by gene flow? The answer to this question should objectively reveal whether gene flow generally places a substantial constraint on evolutionary diversification. We studied multiple independent lake-stream population pairs of threespine stickleback (Gasterosteus aculeatus). For each pair, we quantified adaptive divergence based on morphological traits that have a genetic basis and are subject to divergent selection. We then estimated gene flow based on variation at five unlinked microsatellite loci. We found a consistent and significant pattern for morphological divergence to be positively correlated with genetic divergence and negatively correlated with gene flow. Statistical significance and the amount of variation explained varied within and among traits: 36.1-74.1% for body depth and 11.8-51.7% for gill raker number. Variation within each trait was the result of differences among methods for estimating genetic divergence and gene flow. Variation among traits likely reflects different strengths of divergent selection. We conclude that gene flow has a substantial effect on adaptive divergence in nature but that the magnitude of this effect varies among traits. An alternative explanation is that cause and effect are reversed: adaptive divergence is instead constraining gene flow. This effect seems relatively unimportant for our system because genetic divergence and gene flow were not correlated with ecologically relevant habitat features of lakes (surface area) or streams (width, depth, flow, canopy openness).
The dynamics of the visual system in combining multiple depth cues were investigated by measuring the temporal change in the perceived 3-D shape of a random-dot stimulus with conflicting kinetic depth effect (KDE) and binocular stereopsis cues. The KDE shape perception dominated for the first few seconds, and then was gradually supplanted by the stereo shape perception. The effects of various pre-adaptation stimuli suggested that the temporal change in the perceived shape resulted from a self-adaptation of the KDE mechanism that occurs mainly at the levels of motion and relative motion detection.
A 57-year-old woman was treated for mild presbyopia with implantation of scleral expansion bands (SEB). Although near vision was temporarily restored, the effect dissipated after 1 year. Slitlamp-adapted optical coherence tomography (OCT) at 1310 nm allowed precise cross-sectional visualization of the hyporeflective intrascleral segments. The OCT method provided precise images of the segment depth and thickness, the scleral thickness at the scleral spur, the anterior chamber angle, and the angle-opening distance. Intrascleral tilting of 1 segment was seen; this required removal of the SEB because of marked foreign-body sensation. Noncontact, slitlamp-adapted OCT can be used to evaluate scleral changes after SEB implantation.
OBJECTIVES: This study was conducted to investigate the depths of polymerization inhibition by oxygen, the shear bond strengths to enamel and dentin, and the marginal adaptation in dentin cavities of experimental adhesives containing BisGMA/HEMA of mixtures of low-inhibition BisGMA-dicarbonate with HEMA or with HEMA-carbonate at ratios of 100/0, 80/20, 60/40, 50/50, and 40/60 by weight. METHODS: The inhibition layer thickness was determined microscopically as non-polymerized surface film thickness on three samples each. For bond strength testing, composite cylinders were bonded to enamel and dentin following H3PO4 conditioning with the adhesives dissolved in acetone; marginal adaptation was evaluated in cylindrical dentin cavities. Five specimens each were stored in water for 24 h prior to testing. Shear bond strength results were compared by ANOVA and Duncan's test (p < 0.05), the maximum gap widths by Kruskal-Wallis, ANOVA and Wilcoxon's two-sample test (p < 0.01). RESULTS: Inhibition layer thickness was significantly smaller for modified than for conventional BisGMA/HEMA monomers and increased significantly with HEMA content. In the BisGMA-dicarbonate/HEMA-carbonate group, the inhibited layer was thinner than 1 micron. Apart from the 40 and 50% BisGMA-dicarbonate/HEMA-carbonate mixtures, enamel bond strengths were not significantly different. The highest bond strengths to dentin were 15 and 12 MPa at 50 BisGMA and 50 BisGMA-dicarbonates/HEMA, respectively. The average bond strength for the BisGMA-dicarbonate/HEMA-carbonate group was 5 MPa. Adhesives with 40 and 60% HEMA in the conventional and 40 to 60% HEMA in the dicarbonate/HEMA group showed significantly better marginal adaptation than all others (p < 0.05). SIGNIFICANCE: Carbonate-modified low-inhibition monomers have no advantage as enamel/dentin adhesives compared with conventional BisGMA/HEMA-based resins.
A qualitative method was used to study the life experiences and the adjustment to very old age of a non-institutionalized population of 129 85-year-olds living in Gothenburg, Sweden. In-depth interviews were analyzed and categorized and seven patterns of adjustment emerged: Self-Realizing, Mature Aging, Adapting, Dependent, Resignedly Accepting, Despairing and Withdrawing. Additionally, a coping strategy--ritualization of time and occupations--was revealed in the interviews. These results reflect the heterogeneity among this age group and indicate that the subjective reality should be seriously considered both in further research and in the care of the elderly.
Conventional approaches for proving in situ biodegradation of organic pollutants in aquifers have severe limitations. In the approach described here, patterns in a comprehensive set of microbiological activity and distribution data were analyzed. Measurements were performed on sediment samples gathered at consistent depths in aquifer boreholes spanning a gradient of contaminant concentrations at a buried coal tar site. Microbial adaptation to polyaromatic hydrocarbons (PAHs) was demonstrated by mineralization of naphthalene and phenanthrene in samples from PAH-contaminated, but not adjacent pristine, zones. Furthermore, contaminant-stimulated in situ bacterial growth was indicated because enhanced numbers of protozoa and their bacterial prey were found exclusively in contaminated subsurface samples. The data suggest that many convergent lines of logically linked indirect evidence can effectively document in situ biodegradation of aquifer contaminants.
Intrapulmonary chemoreceptors (IPC) are highly responsive respiratory chemoreceptors that innervate the lungs of birds and diapsid reptiles. IPC are stimulated by low levels of lung Pco(2), inhibited by high levels of lung Pco(2), and their vagal afferents serve as a sensory limb for reflex adjustments of breathing depth and rate. Most IPC exhibit both phasic and tonic sensitivity to CO(2), and spike frequency adaptation (SFA) contributes to their phasic CO(2) responsiveness. To test whether CO(2) responsiveness and SFA in IPC is modulated by a Ca(2+)-linked mechanism, we quantified the role of transmembrane Ca(2+) fluxes and Ca(2+)-related channels on single-unit IPC function in response to phasic changes in inspired Pco(2). We found that 1) broad-spectrum blockade of Ca(2+) channels using cadmium or cobalt and blockade of L-type Ca(2+) channels using nifedipine increased IPC discharge; 2) activation of L-type Ca(2+) channels using BAY K 8644 reduced IPC discharge; 3) blockade of Ca(2+)-activated potassium channels using charybdotoxin (antagonist of large-conductance Ca(2+)-dependent K(+) channel) increased IPC discharge, but neither charybdotoxin nor apamin affected SFA; and 4) blockade of chloride channels, including Ca(2+)-activated chloride channels, with niflumic acid decreased IPC discharge at low Pco(2) and increased IPC discharge at high Pco(2), resulting in a net attenuation of the IPC CO(2) response. We conclude that Ca(2+) influx through L-type Ca(2+) channels has an inhibitory effect on IPC afferent discharge and CO(2) sensitivity, that spike frequency adaptation is not due to apamin- or charybdotoxin-sensitive Ca(2+)-activated K(+) channels in IPC, and that chloride channels blocked by niflumic acid help modulate IPC CO(2) responses.
In this article, the authors describe a recruitment strategy used to enroll female Bangladeshi immigrants into a study of spousal abuse, crucial in the process of identifying abuse in this community. The researchers used a qualitative method involving a three-staged process designed for sampling and recruiting for focus groups and in-depth interviews. The Bangladeshi women declined participation in either of these qualitative genres, but the modified and adapted strategies proved effective in recruiting participants from the tightly knit immigrant community. Key to the success of the effort was the involvement of a Bangladeshi investigator, unspecified time to establish rapport with key informants and representatives of the larger community, and maintaining contact with the target population after completion of the project.
Expertise regarding lesbian mothers is increasingly necessary to members of the legal and helping professions, but there is little empirical research on which to base informed decisions. This paper describes an exploratory study undertaken in response to these needs. Descriptive data were gathered on the everyday experiences of heterosexual and lesbian single mothers. Research methods included participant observation in a wide range of discussion groups and group activities, in-depth interviews, and a questionnaire. Using a phenomenological perspective, comparisons are drawn between heterosexual and lesbian respondents' adaptations to three common concerns: child custody, housing, and employment. While both groups report oppression in the areas of freedom of association, employment, housing, and child custody, the degree of perceived oppression is greater for lesbian mothers. Lesbian mothers exhibit patterns of behavior that may be responses to perceived oppression and that may serve to counterbalance felt difficulties by developing relatively higher levels of independence.