Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Distance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed1985

Relationships among three Muslim and one Hindu endogamous groups of Madhya Pradesh. II. Morpho-behavioural distance analysis.

Morpho-behavioural distances between three endogamous Muslim groups (Sunni, Shia and Bohra) and one Hindu group (Brahman) of Madhya Pradesh, separately for males and females, were estimated. All the differences were statistically significant. The male and female distances were combined into a pooled distance. The Bohra group was found to be distant from all the other groups in both males and females. The relationships between the other three were different in the two sexes-Sunni and Shia forming the closest cluster in males and Sunni and Brahman in females. The Sunni were intermediate between the Shia and the Brahman in both sexes. The morpho-behavioural distances were compared with the genetic distances.

Animals↗
PubMed1979

Genetic distances among the five tribal populations of Andhra, Pradesh, South India.

In this paper, data on genetic distances among five tribal populations ae given. Among the five tribes, Koya Dora, Raj Gond and Naikpod are autochthonous populations of the Deccan plateau whereas the other two groups, Pardhan and Lambadi are migrants. Kova Doras were sampled from five distant localities. Genetic markers typed are: A1A2B0, Rho(D) blood group systems glucose-6-phosphate dehydrogenase deficiency, transferrin, haptoglobin, groupspecific component, haemoglobin, colour-vision deficiency and tastability to P. T. C. Using frequency data for the above nine genetic loci, genetic distances between the five endogamous tribes, and between the five groups of Koya Dora are calculated by adopting the statistical method of Edwards (1971). While genetic distances between Koya Dora, Raj Gond and Lambadi are minimal, the genetic distance between Pardhans and other tribal groups is maximum. Naikpods occupy an intermediate position. The closeness of Lambadi with Koya Dora and RAJ Gond can be regarded as coincidental. Interestingly, the differences in the genetic distance values between five Koya Dora groups are as great as the differences between the five endogamous tribal populations tested for the same loci. Genetic affinities of these tribal populations are discussed in relation to their ethnic origin migration and geographical isolation.

Adult↗
PubMed1984

Fluorescence energy transfer studies on lima bean lectin. Distance between the subunit hydrophobic binding site and the thiol group essential for carbohydrate binding.

Measurements of the efficiency of singlet-singlet energy transfer were used to determine the distance between the hydrophobic binding site and the thiol group required for carbohydrate-binding activity of lima bean lectin. 1-Anilino-8-naphthalenesulfonate, bound to the hydrophobic binding site by noncovalent interactions, was used as the donor. Two different nonfluorescent probes were used as the acceptors: a mercurial, 2-chloromercuri-4-nitrophenol, and a maleimide, 4-dimethylaminophenylazophenyl-4'-maleimide. Acceptor was covalently attached to the thiol group at the putative carbohydrate binding site. The efficiency of energy transfer in both the 1-anilino-8-naphthalenesulfonate/2-chloromercuri-4-nitrophenol and and 1-anilino-8-naphthalenesulfonate/4-dimethylaminophenylazophenyl-4' -maleimide donor-acceptor systems indicated an apparent distance of 28 A between the two sites, assuming that the transition dipole of the donor is not correlated with respect to that of the acceptor and that each donor is quenched by a single acceptor. Using an alternate model wherein each donor is equally quenched by two acceptors on adjacent subunits, an apparent distance of 33.4 A was calculated. The fact that two donor-acceptor pairs with different Förster's critical distance parameters yielded the same distance between the sites is consistent with our assumption of uncorrelated donor-acceptor transition dipoles.

Binding Sites↗
PubMed1978

Effect of experimental alterations in excess weight on aerobic capacity and distance running performance.

To experimentally investigate the effect of excess body weight or fat on maximal oxygen uptake (Vo2 max) and distance running performance, the metabolic response to maximal and submaximal treadmill running and the 12-min run performance were measured in six subjects under each of four added-weight (AW) conditions: normal body weight and 5, 10, and 15% additional external weight, added to the trunk. AW was found to systematically and significantly decrease Vo2 max expressed relative to the total weight carried (ml/min.dg TW), maximal treadmill (TM) run time and 12-min run distance, but not to systematically affect Vo2 max (1/min) or Vo2 max (ml/min.kg FFW). An increase of 5% AW was found, on the average, to decrease Vo2 max (ml/min.kg TW) 2.4 ml, the TM run time 35 sec and the 12-min run distance 89 m. These decreases were a direct consequence of the increased energy cost of running at submaximal speeds. It was concluded that changes in excess body weight can influence Vo2 max expressed relative to body weight and distance run performance independent of any change in cardiovascular capacity. Failure to distinguish the metabolic effects of body fatness from the influence of cardiorespiratory capacity may result in misleading interpretation of distance run test scores.

Adult↗
PubMed1980

Distance running performance and metabolic responses to running in men and women with excess weight experimentally equated.

Metabolic responses to submaximal and maximal treadmill (TM) running and 12-min run performance were measured in 10 female and 10 male adults who regularly engaged in distance running to experimentally investigate the extent to which differences between men and women in metabolic responses to exercise and distance running performance are due to the sex difference in % body fat. The males were studied under two conditions: (1) with normal body weight and (2) with external weight added to the trunk so that the total percent excess weight (% EW) was equal to the % fat of a matched female. Under the added-weight condition, % EW of the males was increased by an average of 7.5%, the mean sex difference in % fat. Equating % EW reduced the mean sex difference in TM run time by 1.3 min (32%) and 12-min run performance by 173 m (30%). These changes in running performance were the result of an average 3.0 ml/min.kg (38%) reduction in the sex difference for the oxygen required per unit fat-free weight (FFW) to run at various submaximal speeds and a 3.9 ml . min-1 . kg-1 (65%) reduction in the sex difference for VO2max expressed relative to the total weight carried. It was concluded that the greater sex-specific, essential body fat of women is one determinant of the sex difference in metabolic responses to running and distance running performance. Because of her greater body fatness, the average woman will utilize more oxygen per unit FFW to run at any given submaximal speed, will have a lower VO2max expressed relative to body weight and, as a result, will maintain a speed on the 12-min run or other similar distance running event which is slower than her male counterpart. Since the sex-specific, essential fat of women cannot be eliminated by diet or training, it provides part of a biological justification for separate distance running performance standards and expectations for men and women.

Adipose Tissue↗
PubMed1994

Peak oxygen deficit predicts sprint and middle-distance track performance.

The purpose of this study was to determine the value of the peak oxygen deficit (POD) as a predictor of sprint and middle-distance track performance. POD, peak blood lactate, VO2peak, lactate threshold, and running economy at 3.6 m.s-1 were measured during horizontal treadmill running in 22 male and 19 female competitive runners of different event specialties. Subjects also completed running performance trials at 100, 200, 400, 800, 1500, and 5000 m. Correlations of track performances with POD (ml.kg-1) (-0.66, -0.71, -0.71, -0.62, -0.52, and -0.40) were moderately strong at the sprint and middle distances, accounting for 44-50% of the performance variance at the three shortest distances. Correlations of track performances with peak blood lactate concentration were lower than with POD and accounted for approximately one-half as much of the performance variance (21-26%) at the three shortest distances. Multiple regression analyses indicated that the POD was the strongest metabolic predictor of 100-, 200- and 400-m performance, and that VO2peak was the strongest metabolic predictor of 800-, 1500-, and 5000-m performance. We conclude that the POD is a moderately strong predictor of sprint and middle-distance track performance.

Adolescent↗
PubMed1994

Variation of bicycle helmet use rates with route distance.

The relationship between bicycle helmet use and demographic measures has been studied extensively. To date, however, there have been very few studies of helmet use by amateur cyclists in organized, noncompetitive, long distance events. Seven hundred eleven riders were observed during three organized events offering route distances ranging from 16 to 161 kilometres. Helmet use ranged from 59% in the shorter distance groups to one hundred percent in the longest distance group. This information can assist organizers of bicycling events by permitting estimation of helmet use rates for planned routes of varying distance.

Adult↗
PubMed1994

Temporal trends in migration in the Aland Islands: effects of population size and geographic distance.

Using a model developed by Relethford (1992), we assess temporal trends (1750-1949) in marital migration in the Aland Islands, Finland, in relation to both geographic distance and population size. The 200-year time period was divided into four 50-year periods. For all time periods both geographic distance and population size are important determinants of migration among 15 Lutheran parishes. The geographic distance parameter of the model decreases significantly over time, and the population size parameter fluctuates slightly but shows no significant change over time. For all time periods migration is negative density dependent, indicating that there is greater relative flow from larger to smaller subdivisions. Even though both the geographic distance and population size parameters are statistically significant, the analysis suggests that geographic distance has a greater relative effect on migration than population size. There is a clear indication of isolate breakdown during the last two time periods (1850-1899 and 1900-1949). Residual analysis indicated that the smallest parish (Sottunga) was a major outlier that showed greater exogamy (less endemicity) than expected from the model.

Emigration and Immigration↗
PubMed1994

Predicting protein folding types by distance functions that make allowances for amino acid interactions.

Given the amino acid composition of a protein, how may one predict its folding type? Although around this problem a number of methods have been proposed, none of them has taken into account the correlative effect among different amino acids, and hence the accuracy of prediction could not be improved to the extent that it should have. In view of this, a new method has been developed in which the similarity between two protein molecules is based on the scale of Mahalanobis distance rather than on the ordinary intuitive geometric distances, such as Minkowski's distance and Euclidian distance. By introducing the Mahalanobis distance, the correlative effect among different amino acids can be automatically incorporated. Predictions have been performed for 131 real proteins consisting of alpha, beta, alpha+beta, and alpha/beta proteins. The results indicate that the rates of correct prediction for both alpha and beta proteins are 100%, and those for alpha+beta and alpha/beta are 88.9 and 89.7%, respectively, with an average accuracy of 94.7%. Predictions have also been performed for 10,000 simulated proteins generated by Monte Carlo sampling for each of the above four folding types, yielding an average accuracy of 95.9%. The accuracy thus obtained for the simulated proteins can avoid the bias due to the limited number of testing proteins selected arbitrarily by different investigators and hence can be regarded as an objective accuracy. It is anticipated that a method with such a high objective accuracy should become a reliable tool in predicting the protein folding type and a useful tool for improving the prediction of secondary structure as well.

Models, Chemical↗
PubMed1993

The influence of interelectrode distance on bipolar recording of sensory nerve action potential. A mathematical study.

Bipolar recording of Extracellular Single Fiber Action Potential (ESFAP) and Sensory Nerve Action Potential (SNAP) were simulated mathematically. The study attempts to analyze the influence of interelectrode distance on the amplitude of bipolar recordings. Simulations of bipolar recordings of ESFAP and SNAP presented four major peaks whose relations changed with the distances between the electrodes which compose the derivation. The maximum amplitude of bipolar ESFAP was produced at similar interelectrode distances for the range of fibers studied in clinical practice. In bipolar recordings of SNAP, the interelectrode distance producing the maximum amplitude increases with the distance between the place of stimulation and the place of recording.

Action Potentials↗
PubMed1997

Influence of direction of view, target-to-endoscope distance and manipulation angle on endoscopic knot tying.

INTRODUCTION: The aim of the study was to investigate the influence of (1) the direction of view of the endoscope, (2) the endoscope-to-task distance and (3) the manipulation angle between the instruments on intracorporeal endoscopic knotting. METHODS: Rigid endoscopes (0 degree, 30 degrees and 45 degrees) were introduced with the objective set at distances of 50, 75, 100, 125 and 150 mm from the task. Needle holders were inserted to make 30 degrees, 60 degrees and 90 degrees manipulation angles. The execution time and knot quality parameters of 2700 knots performed by ten surgeons were obtained. RESULTS: There was no significant difference in the execution time or parameters of knot quality with different endoscopes. The longest execution time (median 95 s, P < 0.0001) and the lowest performance quality score (20.61, P < 0.001) were observed at a distance of 50 mm when compared to other distances. A 60 degrees manipulation angle had a shorter execution time (median 71 s, P < 0.0001) and a higher performance quality score (26.84, P < 0.0001) than either 30 degrees or 90 degrees manipulation angles. CONCLUSION: The direction of view of the endoscope had no significant effect on intracorporeal knotting if the optical axis subtended the same angle with the task surface. The optimal ergonomic conditions include an endoscope-to-target distance of 75-150 mm and a manipulation angle of 60 degrees.

Endoscopy↗
PubMed1996

Wet bonding: effect of drying time and distance.

PURPOSE: To examine the effect of various drying times and air syringe-to-tooth distances on the shear bond strength of a dentin adhesive that requires a wet surface for maximum effectiveness. MATERIALS AND METHODS: Seventy extracted human molars were acid etched. The surface of the etched dentin was rinsed and dried with compressed air for 1, 3, or 5 seconds from a distance from either a distance of 1 or 10 cm. The adhesive One-Step was then applied, composite cylinders were attached and shear bond strengths were obtained. RESULTS: Drying time and distance had a significant impact on the resultant shear bond strengths. Longer drying times and shorter syringe-to-tooth distances negatively affected the bond strength of the adhesive studied.

Acid Etching, Dental↗
PubMed1998

An in vitro study of the correlation between aortic valve diameter and mitral intertrigonal distance: a simple method to select the correct mitral annuloplasty ring size.

BACKGROUND AND AIMS OF THE STUDY: The application of the flexible Duran mitral annuloplasty ring in the treatment of various mitral valvular diseases is a physiologically appealing method of surgical repair. However, accurate identification of the trigonal structures, which is crucial in selecting the proper ring size, cannot always be made with certainty. A method is proposed to calculate the intertrigonal distance (ITD) from the aortic diameter. METHODS: Using digital calipers, the linear intertrigonal distance was measured in human homograft (n = 10) and sheep (n = 10) aortic root specimens. The aortic diameter was obtained from the circumference of the pressurized aortic root. A conversion factor was acquired for each specimen by dividing the aortic diameter with the measured ITD. A single constant conversion factor, which closely approximated the mean of the conversion factors in both groups, was then applied broadly to derive the ITD by calculation from the aortic diameter, which is known. The validity of using this constant conversion factor was tested by comparing the degree of variation of the calculated ITD from the direct measurements of the ITD. RESULTS: The mean of the conversion factors was 0.79 and 0.80 in the human and the sheep roots, respectively. The value 0.80 was used as the constant conversion factor in both groups for calculating the ITD. A paired comparison t-test in each group showed the difference between the calculated intertrigonal distance and the direct measurements of the ITD to be insignificant, validating the use of 0.80 as a constant conversion factor. CONCLUSIONS: The results of the study suggest that the conversion factor of 0.80 can be reliably used to obtain a calculated value of the intertrigonal distance; this method has the potential to aid the surgeon in determining the intertrigonal distance and the proper ring size.

Animals↗
PubMed2002

Can distance learning improve smoking cessation advice in family practice? A randomized trial.

INTRODUCTION: Family physicians (FPs) underuse opportunities to provide smoking cessation advice during routine consultations with patients who smoke. Distance learning is a promising approach to continuing medical education, particularly for FPs practicing in rural and remote areas. We developed a distance learning module, conducting a randomized trial to assess its educational impact on knowledge, attitudes and skills ("competence"), self-rated competence, confidence, and readiness to change. METHODS: Volunteer FPs were randomly allocated to receive either a distance learning module or a preventive care guideline. Self-administered questionnaires were completed at baseline and post-test. RESULTS: Fifty-three FPs enrolled in the study. There were no changes in knowledge or attitudes. Change in skills was limited to a reduction in use of one ineffective technique, namely "nicotine fading." Change in self-rated competence between baseline and post-test was significantly greater for the intervention than for the control group, however (p = .03). Although self-ratings of confidence increased significantly between baseline and post-test in both groups, the magnitude of change was no greater in the intervention than the control group (p = .3). Both groups demonstrated only nonsignificant shifts in readiness to change. DISCUSSION: These modest changes are of uncertain educational value, inviting caution before recommending distance learning approaches to promote smoking cessation advice in family practice.

Australia↗
PubMed1982

The development of proxemic spacing behavior: children's distances to surrounding playmates and adults change between 6 months and 5 years of age.

The patterns of distances maintained between 30 children and 15 adult caretakers were measured to determine developmental trends in children's patterns of interpersonal spacing toward adults and playmates. Children's positions during free play were photographed at 60-sec intervals and analyzed with a computer to determine the mean distances children maintained toward their 1st through 5th nearest adult caretakers and toward their 1st through 5th nearest playmates. Children's distances from adults increased with age, while distances from playmates and spatial variability decreased with age. Only infants (6-18 months) stayed significantly close to any of their adult caretakers; toddlers (19-27 months) and preschoolers (30-60 months) avoided proximity to their 3rd through 5th nearest adult caretakers more than could be expected by chance. All age groups significantly avoided proximity to their 4th and 5th nearest playmates; avoidance of playmates' space decreased with age.

Adult↗
PubMed2003

The kinaesthetic perception of Euclidean distance: a study of the detour effect.

An experiment investigated the mechanisms by which humans estimate Euclidean distances on the basis of kinaesthetic cues. Blindfolded participants followed straight and curvilinear paths with a hand-held stylus (encoding phase). Then, with a straight movement, they estimated the Euclidean distance between the start- and end-points of the path (response phase). The experiment contrasted an On-axis condition, in which encoding and response movements were spatially aligned, and an Off-axis condition, in which they were displaced laterally. Performances were slightly more accurate in the On-axis condition than in the Off-axis condition. In both conditions, however, errors were consistently smaller when the path covered a larger surface. The results showed that small paths yielded an overestimation of the Euclidean distance, the relative errors increasing with the length of curvilinear paths. The findings are compared with results of other studies in which distances were estimated on the basis of haptic cues.

Arm↗
PubMed1997

An analysis of spatiotemporal variability during prehension movements: effects of object size and distance.

Human prehension movements have been studied with regard to the parallel processing of motor control and sensorimotor coordination. Temporal aspects of the movement (e.g., onset time and duration) have been studied extensively, while spatial aspects have not been studied systematically. Thus, the purpose of this study was to examine spatiotemporal variability of the transport (wrist trajectory) and grasp (grip aperture between the index finger and the thumb) components. In this experiment, the extrinsic (e.g., distance) and intrinsic object properties (e.g., object size) were manipulated. Subjects were required to pick up an aluminum cylinder as quickly and accurately as possible using the index finger and the thumb. It was found that object size significantly affected both transport and grasp components. Distance mainly affected the transport component. These kinematic results were consistent with the findings of earlier studies. Furthermore, the distribution of mean within-subject variability across normalized movement time for the transport component was not the same as that of the grasp component, suggesting that the different motor control processes exist. The peak amplitudes in variability of the wrist trajectory and the grip aperture were obtained at similar points throughout movement time. Furthermore, the peak of wrist variability depended on distance not object size, while that of aperture variability depended on both distance and object size. These results strongly support the hypothesis that the grasp component is adjusted using dynamic information provided from the transport component as the wrist moves toward the object. We also found that wrist variability converged to the target point, while aperture variability was biphasic: it converged, at least, around the point of maximum aperture in the first phase and then remained constant in the second phase. This result suggests that the two components are under different control processes. We hypothesize that the transport component can be modeled as a single feedforward system, while the grasp component can be divided into two separate mechanisms.

Adult↗
PubMed2006

Local visual homing by matched-filter descent in image distances.

In natural images, the distance measure between two images taken at different locations rises smoothly with increasing distance between the locations. This fact can be exploited for local visual homing where the task is to reach a goal location that is characterized by a snapshot image: descending in the image distance will lead the agent to the goal location. To compute an estimate of the spatial gradient in the distance measure, its value must be sampled at three noncollinear points. An animal or robot would have to insert exploratory movements into its home trajectory to collect these samples. Here we suggest a method based on the matched-filter concept that allows one to estimate the gradient without exploratory movements. Two matched filters--optical flow fields resulting from translatory movements in the horizontal plane--are used to predict two images in perpendicular directions from the current location. We investigate the relation to differential flow methods applied to the local homing problem and show that the matched-filter approach produces reliable homing behavior on image databases. Two alternative methods that only require a single matched filter are suggested. The matched-filter concept is also applied to derive a home-vector equation for a Fourier-based parameter method.

Animals↗