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Results for “Consistency”

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PubMed2006

Dietary consistency and plasticity of masseter fiber architecture in postweaning rabbits.

Dietary consistency has been shown to influence cross-sectional area and fiber type composition of the masticatory muscles. However, little is known about the effects of dietary consistency on masticatory muscle fiber architecture. In this study, we explore the effects of dietary consistency on the internal architecture of rabbit masseter muscle. Because activity patterns of the rabbit chewing muscles show inter- and intramuscular heterogeneity, we evaluate if alterations in fiber architecture are homogeneous across various portions of the superficial masseter muscle. We compared masseter muscle fiber architecture between two groups of weanling rabbits raised on different diets for 105 days. One group was raised on a diet of ground rabbit pellets to model underuse of the masticatory complex, while the other group was fed a diet of intact pellets and hay blocks to model an overuse diet. In all portions of the superficial masseter, physiological cross-sectional areas (PCSAs) are greater in the overuse compared to underuse diet rabbits. Thus, the mechanical demands for larger muscle and bite forces associated with early and prolonged exposure to a tough diet are met by an increase in PCSA of the superficial masseter. The larger PCSA is due entirely to increased muscle mass, as the two rabbit groups show no differences in either fiber length or angle of pinnation. Thus, increasing pinnation angle is not a necessary biomechanical solution to improving muscle and bite force during growth. The change in PCSA but not fiber length suggests that variation in dietary consistency has an impact on maximum force production but not necessarily on excursion or contraction velocity.

Adaptation, Physiological↗

PubMed2006

Defining "success" in recruitment of underrepresented populations to cancer clinical trials: moving toward a more consistent approach.

Although medically underserved groups bear a heavy burden of cancer disease and governmental agencies have required inclusion of minorities and women in cancer clinical trials since 1993, many of these groups are underrepresented in cancer prevention or treatment clinical trials. To assess and enhance recruitment of underrepresented populations into cancer-related clinical trials, investigators and governmental agencies need consistent measurement approaches for recruitment that can be applied to diverse settings where trials are conducted. We conducted a systematic review to evaluate what measurement approaches were used to evaluate the success of recruitment of underrepresented groups into cancer prevention or treatment trials, and whether these recruitment goals were stated a priori. Only two articles reported an a priori recruitment goal. The recruitment measurement approaches varied considerably, with no consistent standard, especially for individual trials. By using the empiric evidence from this review in conjunction with the National Institutes of Health (NIH) guidelines, we constructed a framework for choosing consistent a priori recruitment goals for underrepresented groups based on the research question and study location. Using consistent measurement approaches for underrepresented groups will improve comparability of recruitment strategies across trials, improve equity in distribution of benefits and burdens of cancer-related clinical trials, and may improve applicability of trial results to multiple populations.

Clinical Competence↗

PubMed1999

The consistency of individual differences in behaviour: temperature effects on antipredator behaviour in garter snakes.

Differences among individuals are necessary for natural selection to occur. The extent and expression of these differences can limit the power of selection to cause evolutionary change. When individuals inconsistently express a trait, selection is less powerful. Labile traits such as behaviour are most likely to be inconsistent in their expression, because of the substantial role of environmental factors in their immediate expression. Previous work has focused on the consistency, or repeatability, of individual behaviour across different environments or within a single environment; little is known about how repeatability within an environment changes across environments. To address this issue, we examined the consistency of antipredator behaviour in juvenile garter snakes in different thermal environments. A group of 59 laboratory-born garter snakes Thamnophis ordinoides, was repeatedly assayed for sprint speed, distance crawled, and number of reversals performed during flight and antipredator display. Antipredator display showed very little variation and could not be analysed. Each individual was tested three times at each of three temperatures chosen to span the range of temperatures that snakes encounter in the field (15, 22.5, 30 degrees C). Temperature had substantial effects on the average expression of each behaviour; snakes crawled more slowly, for shorter distances, and performed fewer reversals at cooler temperatures. Individuals showed significant consistency in their behaviour, and this consistency of expression was not affected by temperature. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1998

Distributed versus localist representations: evidence from a study of item consistency in a case of classical anomia.

Models of word production and comprehension can be split into two broad classes: localist and distributed. In localist architectures each word within the lexicon is represented by a single unit. The distributed approach, on the other hand, encodes each lexical item as a pattern of activation across a set of shared units. If we assume that the localist representations are more than a convenient shorthand for distributed representations at the neuroanatomical level, it should be possible to find patients who, after brain injury, have lost specific words from their premorbid vocabulary. Following a closed head injury, JS had severe word-finding difficulties with no measurable semantic impairment nor did he make phonological errors in naming. Cueing with an initial phoneme proved relatively ineffective. JS showed a high degree of item consistency across three administrations of two tests of naming to confrontation. This consistency could not be predicted from a linear combination of psycholinguistic variables but the distribution fitted a stochastic model in which it is assumed that a proportion of items have become consistently unavailable. Further evidence is presented which suggests that these items are not, in fact, lost but rather have a very low probability of retrieval. Given phonemic cueing of sufficient length, or delayed repetition priming from a written word, the consistently unnamed items were produced by JS. Additional data is reported which seems to support a distributed model of speech production. JS's naming accuracy for one set of pictures was found to predict his performance on a second set of items only when the names of the pictures were both semantically and phonologically related (e.g., cat-rat). There was no association for pairs of pictures if they were only semantically (e.g., cat-dog) or phonologically related (e.g., cat-cap). It is argued that JS's data are best described in terms of a graded, non-linear, distributed model of speech production.

Adult↗

PubMed1997

Consistency, characters, and the likelihood of correct phylogenetic inference.

Computer simulations of character-state evolution in 8, 16, 32, and 64 ingroup taxa with a known set of relationships demonstrate that the maximum probability of correct phylogenetic inference increases with the number of variable (or informative) characters and their consistency index and decreases with the number of taxa, when the consistency index has been standardized to eliminate its dependence on the number of taxa. Equations for the probability of correct phylogenetic inference and for the standardized consistency indices (including or excluding autapomorphies) are derived. Given that actual studies based on DNA restriction sites and sequences generate more characters with a higher level of consistency than comparable studies based on morphology, calculations suggest that such molecular studies may often provide a more precise guide to phylogenetic relationships.

Computer Simulation↗

PubMed1990

The internal consistency and concurrent validity of a Spanish translation of the Child Behavior Checklist.

The Child Behavior Checklist's applicability to a Hispanic sample was assessed by an examination of the instrument's internal consistency and concurrent validity. The CBCL and TRF were administered to a community sample representative of children of Puerto Rico aged 4 to 16. Cronbach's alpha was used to assess the internal consistency of empirically derived scales. The relation of CBCL and TRF scores to clinical diagnosis, adaptive functioning, and need for services served as indicators of the concurrent validity of the instrument's Spanish version. The results indicate that the total behavior problem scores on the instruments are good continuous measures of maladjustment for children in Puerto Rico. A child with high values on the scales has a high probability of being classified as a case by a psychiatrist. High levels of internal consistency were found in most subscales. Only scales comprising low prevalence problems showed poor internal consistency.

Adolescent↗

PubMed1991

Consistency of ancestry reporting between parents and children in the 1986 census.

The author examines responses to a question on ancestry that was included in the 1986 census of Australia, with a focus on consistencies between the responses of parents and children. It is found that "the level of consistency was more than 90 per cent when both parents were of the same ancestry; when parents were of different or mixed ancestries, the level of consistency was lower. It was estimated that about 75 per cent of all dependent children had an ancestry response consistent with that of the parent or parents with whom they lived."

Adolescent↗

PubMed2002

Spatiotemporal consistency of human mandibular and head-neck movement trajectories during jaw opening-closing tasks.

Previous studies of spatial and temporal coordination between human mandibular and head-neck movements during single as well as rhythmic jaw opening-closing tasks suggest that these movements are regulated by central nervous commands common for jaw and neck muscles. The present study evaluated the spatiotemporal consistency of concomitant mandibular and head-neck movements during repeated single jaw opening-closing tasks, in short- as well as long-term perspectives and at different speeds. The subjects were seated in an upright position without head support. They were instructed to perform single maximal jaw opening-closing movements, repeated ten times for fast and slow speed, respectively. Recordings were made at two sessions. A wireless optoelectronic technique was used to record three-dimensional mandibular and head-neck movements. The spatiotemporal consistency of repeated movement trajectories of the mandible (both in relation to the head and in space) and of the head-neck was quantitatively assessed by a spatiotemporal index (STI). In addition, mean movement trajectory patterns were compared for speed and recording sessions (expressed as correlation coefficient, r). The results showed relatively small STI (high degree of spatiotemporal consistency) and high r (reproducible trajectory patterns) values, both in short- and long-term perspectives, for concomitant mandibular and head-neck movements. The data were not generally speed related. In conclusion, the present results suggest a high degree of spatiotemporal consistency of the kinematic patterns of mandibular and head-neck movements during jaw opening-closing, in short- as well as long-term perspectives. They also indicate that underlying neural processes are invariant in nature. The results give further support to the notion of a tight functional coupling between the human jaw and the neck motor systems during natural jaw function.

Adult↗

PubMed2000

A model of binocular stereopsis including a global consistency constraint.

The binocular correspondence problem was solved by implementing the uniqueness constraint and the continuity constraint, as proposed by Marr and Poggio [Marr D, PoggioT (1976) Science 194: 283-287]. However, these constraints are not sufficient to define the proper correspondence uniquely. With these constraints, random-dot stereograms (RDSs), consisting of the periodic textures in each image, are treated as a correspondence of surfaces composed of patches of alternating values of disparity. This is quite different from the surface we perceive through the RDSs, that is a surface characterized by a single depth. Because these constraints are local, they cannot produce the global optimum of correspondence. To obtain the global optimum of correspondence, we propose a model of binocular stereopsis in which a global measure of correspondence is explicitly employed. The model consists of two hierarchical systems. First, the lower system processes various correspondences based on the uniqueness constraint. Second, the higher system provides a global measure of correspondence for the disparity in question. The higher system uniquely determines the global optimum of correspondence in the lower system through the recurrent loop between hierarchical systems. The convergence of the recurrent loop is determined by the consistency between the hierarchical systems. The condition is termed the 'global consistency constraint.

Algorithms↗

PubMed2002

Bolus consistency and swallowing in children and adults.

Research has shown that swallowing in adults is affected by bolus consistency. Little is known, however, regarding the effect of bolus consistency on swallowing in children. Electromyographic (EMG) data from typically developing five- and eight-year-old-children and adults were obtained from the following muscles as they swallowed boluses of different consistencies: (1) right upper lip, (2) right lower lip, (3) submental, and (4) laryngeal strap. Signal analyses included calculating EMG onset and offset and average EMG amplitude of muscle activity during swallowing. Findings revealed that by five years of age, children employ adultlike control strategies during swallowing: significant differences in duration and magnitude of muscle activity resulted as a function of bolus consistency. General observations revealed, however, that swallowing in children is characterized by muscle activity that is shorter in duration. Similarities and differences in the biomechanics of swallowing between children and adults are important to consider during clinical evaluations and treatment of children with dysphagia.

Adult↗

PubMed1998

Consistency of lumbar discograms of the same disc obtained twice at a 2-week interval: influence of needle tip position.

: Although numerous papers have emphasized the importance of accurate needle positioning in lumbar discography, no concrete evidence is available to support this contention, and no study has evaluated the image consistency of discography as influenced by this factor. By observing the consistency of two images in relation to needle tip position we aimed to clarify the importance of needle positioning in discography. One hundred and ninety-two patients (324 discs) receiving steroid intradiscal therapy in whom discography of the same disc was performed twice at a 2-week interval and in whom the needle tip position was within the acceptable range (as defined by us) were studied. The patients were divided into two groups: in group G, in whom the needle tip was within a limited range on both discograms, and group P, in whom the needle tip was in this range on only one discogram. Image consistency was compared roentgenographically in the two groups. The consistent image rate for the total number of discs was 48.5%, being significantly higher in group G (53.2%) than in group P (39.0%). The rates were lower in the nucleus pulposus and the posterior portion of the disc than in the other disc areas, but were significantly higher in group G (85. 4% and 75.0%, respectively, for these two areas). The necessity for accurate needle tip positioning was proved roentgenographically.

Adolescent↗

PubMed2006

Sexual behavior, psychosocial and knowledge differences between consistent, inconsistent and non-users of condoms: a study of female bar and hotel workers in Moshi, Tanzania.

Understanding psychosocial, sexual behavior and knowledge differences between never, inconsistent and consistent condom users can improve interventions to increase condom use in resource-poor countries, but they have not been adequately studied. We examined these differences in a cohort of 961 female hotel and bar workers in Moshi, Tanzania. Forty-nine percent of women reported no condom use; 39% reported inconsistent use, and 12% reported consistent use. Women with multiple sexual partners in the past five years were less likely to be consistent rather than inconsistent users as were women who had ever exchanged sex for gifts or money. Inconsistent users had higher condom knowledge and higher perceived acceptability of condom use than did never users, but they did not differ from consistent users by these factors. There are important differences between women by level of condom use. These findings can help inform interventions to increase condom use.

Adolescent↗

PubMed2005

Consistency of epidemiologic estimates.

BACKGROUND: The epidemiology of a disease describes numbers of people becoming incident, being prevalent, recovering, surviving, and dying from the disease or from other causes. As a matter of accounting principle, the inflow, stock, and outflows must be compatible, and if we could observe completely every person involved, the epidemiologic estimates describing the disease would be consistent. Lack of consistency is an indicator for possible measurement error. METHODS: We examined the consistency of estimates of incidence, prevalence, and excess mortality of dementia from the Rotterdam Study. We used the incidence and excess mortality estimates to calculate with a mathematical disease model a predicted prevalence, and compared the predicted to the observed prevalence. RESULTS: Predicted prevalence is in most age groups lower than observed, and the difference between them is significant for some age groups. CONCLUSIONS: The observed discrepancy could be due to overestimates of prevalence or excess mortality, or an underestimate of incidence, or a combination of all three. We conclude from an analysis of possible causes that it is not possible to say which contributes most to the discrepancy. Estimating dementia incidence in an aging cohort presents a dilemma: with a short follow-up border-line incident cases are easily missed, and with longer follow-up measurement problems increase due to the associated aging of the cohort. Checking for consistency is a useful strategy to signal possible measurement error, but some sources of error may be impossible to avoid.

Aged↗

PubMed1989

Consistent benefits for the system designer and the end-user.

Command languages which are internally consistent are said to be easier to learn. The level of consistency - or degree of user complexity - of any command language is usually defined using one of a number of formal grammars, and yet consistency need not be so rigorously defined. It is proposed that diagrams can provide a suitable meta-language with which to illustrate the consistent properties of any command set; and a particular type of diagram - the 'command wheel' - is described. Command wheels offer a number of advantages over formal specifications, being simple to construct and allowing more discretion in the design process. In a study of word-processor users, it was found that properties of command wheels allowed the accurate prediction of user's behaviour, both in terms of their on-line performance, and their subsequent ability to recall commands.

Journal Article↗

PubMed1984

The consistency principle in protein structure and pathways of folding.

It is pointed out that various energy terms contributing to stabilize the native state of globular proteins are consistent in the first approximation with each other in the native state. This means that each energy term is individually minimized at the minimum point of the total energy. I proposed (1) to call this fact "the consistency principle in protein structure." The fair success of various methods of prediction of the secondary structures in globular proteins from their amino acid sequence is often interpreted as indicating the dominance of the short-range interactions in determining the local structures of the polypeptide chains. Partly from such a point of view, the hierarchic condensation model has been popular for the process of protein folding. However the consistency principle indicates that the short-range interactions are just one type of intramolecular interaction which contributes to stabilization of the native structure together with other mutually consistent types of intramolecular interactions. Therefore the hierarchic condensation model is not necessarily a unique model of protein folding. Roles of a possible nonspecific globular state, stabilized by nonspecific long-range intramolecular interactions, in the folding process are discussed. It is expected that this nonspecific globular state is observed either as an equilibrium or a kinetic intermediate state between the unfolded and the folded native states. Observation as a kinetic intermediate state is expected to occur in experiments done under strongly refolding conditions. In this case the polypeptide chain in the unfolded state collapses into a nonspecific globule by the action of nonspecific long-range intramolecular interactions. Two possible mechanisms of the transition from the nonspecific globular state to the specific native folded state are discussed. In an experiment done under weakly refolding conditions, folding is expected to occur according to the embryo-nucleus model. This model is a refined version of the hierarchic condensation model. Refinement is done by taking into account the fact that the intermediate structures assumed in the hierarchic condensation model are unstable against both the native folded state and the unfolded state. A nucleus is an ordered structure of a certain size. Ordered structures of a size larger than a nucleus tend to fold further to become the native specific globule. Ordered structures of a size smaller than a nucleus tend to unfold. Embryos are intrinsically unstable ordered structures smaller than a nucleus. Folding occurs when embryos grow in size to become a nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

Drug Stability↗

PubMed1982

Consistency in catecholamine and cortisol excretion in males and females.

Data from a series of experiments performed on 24 female and 24 male subjects were used to evaluate the consistency in urinary catecholamine and cortisol excretion. Data were available from 8 laboratory situations of varying activity level and content, spaced at intervals of maximum 3 months. Correlational analyses showed that for cortisol, interindividual consistency was higher for measures obtained on the same day than for measures obtained on different days. Interindividual consistency was generally high in catecholamine and cortisol excretion during non-stressful situations in both sexes. During experimental stress, however, consistency was as high as during nonstress for males, while it was lower for females. Analysis of variance components confirmed these results and showed that in males variation due to interindividual differences was high during both baseline and experimental-stress situations, while in females it was high during baseline situations only. During experimental stress, variation for females was due primarily to interaction. It is suggested that the males showed a more generalized stress response over situations than the females.

Adolescent↗

PubMed1994

Intertask consistency of hemodynamic responses to laboratory stressors in a biracial sample of men and women.

Cardiovascular responses were examined in a community sample of 128 subjects, comprised of 58 African American and 70 Caucasian American men and women. Subjects completed a battery of laboratory stressors including mental arithmetic, reaction time, a speech task, and the cold pressor test. In addition to systolic and diastolic blood pressures, the underlying hemodynamic parameters of cardiac output and total peripheral resistance were assessed. In order to explore intertask consistency of response in both ethnic groups and both gender groups, correlational analyses were conducted separately for each group. For the psychological tasks, unanimously significant coefficients were observed. Intertask consistency between psychological tasks and the cold pressor was also considerable, but was somewhat less impressive (particularly for blood pressure) than that observed among the psychological tasks themselves. With regard to hemodynamic responses, cardiac output and total peripheral resistance demonstrated intertask consistency equal to, if not greater than, that shown by systolic and diastolic blood pressure, this consistency being evident for each ethnic and each gender group.

Adolescent↗

PubMed1992

The consistency of facial expressions of pain: a comparison across modalities.

A number of facial actions have been found to be associated with pain. However, the consistency with which these actions occur during pain of different types has not been examined. This paper focuses on the consistency of facial expressions during pain induced by several modalities of nociceptive stimulation. Forty-one subjects were exposed to pain induced by electric shock, cold, pressure and ischemia. Facial actions during painful and pain-free periods were measured with the Facial Action Coding System. Four actions showed evidence of a consistent association with pain, increasing in likelihood, intensity or duration across all modalities: brow lowering, tightening and closing of the eye lids and nose wrinkling/upper lip raising. Factor analyses suggested that the facial actions reflected a general factor with a reasonably consistent pattern across modalities which could be combined into a sensitive single measure of pain expression. The findings suggest that the 4 actions identified carry the bulk of facial information about pain. They also provide evidence for the existence of a universal facial expression of pain. Implications of the findings for the measurement of pain expression are discussed.

Adult↗