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PubMed2005

Long-working-distance incoherent-light interference microscope.

We describe the design and operation of a long-working-distance, incoherent light interference microscope that has been developed to address the growing demand for new microsystem characterization tools. The design of the new microscope is similar to that of a Linnik interference microscope and thus preserves the full working distance of the long-working-distance objectives utilized. However, in contrast to a traditional Linnik microscope, the new microscope does not rely on the use of matched objectives in the sample and the reference arms of the interferometer. An adjustable optical configuration has been devised that allows the total optical path length, wavefront curvature, and dispersion of the reference arm to be matched to the sample arm of the interferometer. The reference arm configuration can be adjusted to provide matching for 5x, 10x, and 20x long-working-distance objectives in the sample arm. In addition to retaining the full working distance of the sample arm objectives, the new design allows interference images to be acquired in situations in which intervening windows are necessary, such as occur with packaged microsystems, microfluidic devices, and cryogenic, vacuum, or environmental chamber studies of microsystem performance. The interference microscope is compatible with phase-shifting interferometry, vertical scanning interferometry, and stroboscopic measurement of dynamic processes.

Equipment Design↗
PubMed1976

Effects of luminance and stimulus distance on accommodation and visual resolution.

Measurements of accommodation and visual resolution were obtained at a number of luminance levels and stimulus distances. With reductions in luminance the eye approached a "fixed-focus" condition of accommodation for intermediate distances, resulting in successively larger errors in accommodation for both near and far stimuli. The visual resolution values were initially affected by both the luminance and distance of the stimulus. Subsequent measurements of resolution, following the correction of accommodative errors, were found to be independent of the stimulus distance. The findings are discussed with regard to the problems of "night myopia" and variations in visual resolution with stimulus distance.

Accommodation, Ocular↗
PubMed2004

Distance walked in the 6-minute test soon after cardiac surgery: toward an efficient use in the individual patient.

STUDY OBJECTIVES: To describe the results of the 6-min walking test performed on admission to an intensive rehabilitation program after cardiac surgery and to develop, through an algorithm based on a few clinical indicators, reference tables in order to apply distance walked values more efficiently in the individual patient at his/her entry into a cardiac rehabilitation program. SETTING: Intensive cardiac rehabilitation units. PATIENTS AND INTERVENTION: A total of 2,555 consecutive patients admitted between January 2001 and December 2002 to the Cardiac Rehabilitation Department of the S. Maugeri Foundation early after cardiac surgery performed a 6-min walking test within the fourth day of hospital admission. RESULTS: The mean walked distance was 296 +/- 111 m (+/- SD). At multiple regression analysis, age, sex, and comorbidity were independent predictors of walking test performance. The left ventricular ejection fraction only influenced the walked distance in men. Starting from these variables, we propose an algorithm and specific reference tables. CONCLUSIONS: Reference values for gender-, age-, comorbidity-, and systolic function-related test performance in patients after cardiac surgery at the beginning of the rehabilitative phase are provided. Once a new patient has been categorized through simple parameters, the actual distance walked could be compared with the matched reference value, thus making the interpretation of the result more efficient. The walked distance might be used to define different levels of disability and to personalize therapeutic exercise prescriptions.

Aged↗
PubMed2003

Distance from roads and cities as a predictor of habitat loss and fragmentation in the caatinga vegetation of Brazil.

Roads and cities represent huge sources of degradation for adjacent ecosystems regarding nutrient cycling, energy, water flow and species composition. In this study we test the hypothesis that distance from roads and cities is associated with habitat loss and fragmentation in the caatinga vegetation--a dry forest to scrub vegetation that covers ca. 736,000 km2 of northeast Brazil. The study site comprised a 2,828.8 km2 piece (64 km x 44.2 km) of Xingó region (09 degrees 36'S, 37 degrees 50'W), which is located between the States of Alagoas and Sergipe. Based on satellite imagery we mapped the remaining vegetation, 145 km of paved roads and the seven small-sized cities set in the study site. A positive correlation was found between the combined distance from roads and cities and the percentage of remaining vegetation as it dropped from 18% at 12 km distant to 5.9% at 1 km distant from cities and roads. Thus, remaining vegetation was reduced by one third near cities and roads. A positive correlation was also found between distance from cities and roads and the percentage of fragments larger than 200 ha, which ranged from 3.6% (within 3 km distance class) to 23.3% (15 km distance class) of all fragments. Our results suggest a road/city-effect zone of 12 to 15 km width, over which habitat loss and fragmentation extend throughout the caatinga vegetation. These findings should be considered in the regional polices for biodiversity conservation and economic development of the caatinga region.

Brazil↗
PubMed2006

Effect of light curing tip distance and resin shade on microhardness of a hybrid resin composite.

Resin composite shades and resin composite polymerization performed with a distanced light tip are factors that can affect polymerization effectiveness. This in vitro study aimed to evaluate the influence of curing tip distance and resin shade on the microhardness of a hybrid resin composite (Z250-3M ESPE). Forty-five resin composite specimens were randomly prepared and divided into nine experimental groups (n = 5): three curing tip distances (2 mm, 4 mm, and 8 mm) and three resin shades (A1, A3.5, and C2). All samples were polymerized with a continuous output at 550 mW/cm(2). After 24 hours, Knoop microhardness measurements were obtained on the top and bottom surfaces of the sample, with a load of 25 grams for 10 seconds. Five indentations were performed on each surface of each sample. Results showed that bottom surface samples light-cured at 2 mm and 4 mm presented significantly higher hardness values than samples light-cured at 8 mm. The resin shade A1 presented higher hardness values and was statistically different from C2. The resin shade A3.5 did not present statistical differences from A1 and C2. For the top surface, there were no statistical differences among the curing tip distances. For all experimental conditions, the top surface showed higher hardness values than the bottom surface. It was concluded that light curing tip distance and resin shade are important factors to be considered for obtaining adequate polymerization.

Color↗
PubMed2000

The effect of inter-implant distance on the height of inter-implant bone crest.

BACKGROUND: The biologic width around implants has been well documented in the literature. Once an implant is uncovered, vertical bone loss of 1.5 to 2 mm is evidenced apical to the newly established implant-abutment interface. The purpose of this study was to evaluate the lateral dimension of the bone loss at the implant-abutment interface and to determine if this lateral dimension has an effect on the height of the crest of bone between adjacent implants separated by different distances. METHODS: Radiographic measurements were taken in 36 patients who had 2 adjacent implants present. Lateral bone loss was measured from the crest of bone to the implant surface. In addition, the crestal bone loss was also measured from a line drawn between the tops of the adjacent implants. The data were divided into 2 groups, based on the inter-implant distance at the implant shoulder. RESULTS: The results demonstrated that the lateral bone loss was 1.34 mm from the mesial implant shoulder and 1.40 mm from the distal implant shoulder between the adjacent implants. In addition, the crestal bone loss for implants with a greater than 3 mm distance between them was 0.45 mm, while the implants that had a distance of 3 mm or less between them had a crestal bone loss of 1.04 mm. CONCLUSIONS: This study demonstrates that there is a lateral component to the bone loss around implants in addition to the more commonly discussed vertical component. The clinical significance of this phenomenon is that the increased crestal bone loss would result in an increase in the distance between the base of the contact point of the adjacent crowns and the crest of bone. This could determine whether the papilla was present or absent between 2 implants as has previously been reported between 2 teeth. Selective utilization of implants with a smaller diameter at the implant-abutment interface may be beneficial when multiple implants are to be placed in the esthetic zone so that a minimum of 3 mm of bone can be retained between them at the implant-abutment level.

Alveolar Bone Loss↗
PubMed1993

Information-processing mediating the location-distance interference in motor short-term memory.

We reviewed the literature on basic psychological correlates of the well-known phenomenon of the location-distance interference in motor short-term memory (Kerr, 1978; Walsh, Russell, Imanaka, & James, 1979). The location-distance interference in motor short-term memory has frequently been demonstrated as an unavoidable interference phenomenon observed in the reproduction of movement location and distance in arm positioning. The most important aspect of this phenomenon is that even when a subject concentrates on a specific cue (i.e., either end-location or distance) the other cue is also coded unintentionally and, as a result, the reproduction movement guided on the basis of the specific cue is unavoidably influenced by the other nonspecific cue. In this review article, we first reviewed the literature on the basic theories and nature of short-term memory, particularly on the limited processing capacity. We then referred to the unlimited, automatic processing in visual-verbal domains, referring to the Stroop phenomenon. Finally, in conjunction with the notion of automatic processing, we examined the possible aspects of information processing which may be responsible for mediating the location-distance interference in motor short-term memory.

Cues↗
PubMed1993

Effects of the direction and distance of horizontal arm movements on local muscular strain--a fundamental study on the teller workplace in bank.

This study was conducted to examine the relative differences in the muscular strain of the hand-arm-shoulder system in the repetitive arm movements which would directly depend on the layout of devices at teller counter. The subjects were five young male adults. The manual handling task was standardized and the repetition frequency was in self-pace. The arm movements were characterized by the different direction measured from the frontal plane of the subject between 0 degrees to 150 degrees combined with the distance measured from the acromion to the fixed points of 300, 500 and 700mm. The movements to all of the fourteen points tested were evaluated on both sides of the arms and shoulders by the integration of the EMG signals (IEMG) as to m. deltoid pars media and clavicularis, m. trapezius pars descendens, m. pectoralis major pars clavicularis and m. extensor carpi radialis brevis. It was found that IEMG of the deltoid muscles were sensitive to the direction and distance of the arm movements while the trapezius muscle showed the relative lower dependence on the direction. There were significant combined effects of the direction and distance in all muscles; i.e. effect of reach distance was greater with decreasing the arm angle, which was obvious at distance longer than 500mm in the arm abduction. When IEMG was divided by the task time in self-pace which increased in the arm abduction, the peak value was observed at the angle of 30 degrees. It was suggested that if the repetitive movement was required at the same frequency as at the angle of 30 degrees the position near the arm abduction (the angle of 0 degrees) would become the most expensive working direction.

Adult↗
PubMed1989

Prerequisites in distance running performance of female runners.

We investigated which attribute or what combination of attributes would best account for distance running performance of female runners. The subjects were 30 well-trained female distance runners, aged 19 to 23 years. Anthropometric and body composition characteristics, pulmonary function characteristics, blood properties, and cardiorespiratory function characteristics were measured at rest or during submaximal and maximal exercise. Analyses of the data showed that the relationship of oxygen uptake corresponding to lactate threshold (VO2T, ml.kg-1.min-1) with each distance running performance was substantially higher as compared with the relationship of other independent variables including maximal oxygen uptake (VO2max). Furthermore, multiple regression analysis indicated that running performances in 3,000m, 5,000m, and 10,000m are best accounted for by a combination of VO2/LT (X1), fat-free weight (X2), and/or mean corpuscular volume (X3). A multiple regression equation for predicting the 5,000m (Y, s) running performance was formulated as Y = -14.75X1-3. 03X2-5.79X3 + 2282.1. We suggest that VO2max would not stand alone as a decisive factor of distance running success in female runners, and that the distance running performance could be better accounted for by a combination of several attributes relating to lactate threshold, body composition, and/or hematological status. The linear regression of the predicted running performance on the actually measured running performance can be accepted in the range of 986-1197s.

Adult↗
PubMed1999

Assessment of long-distance running performance in elite male runners using onset of blood lactate accumulation.

The purpose of this study was to evaluate the relationship between onset of blood lactate accumulation (OBLA) and long-distance running performance in order to examine whether OBLA can be a good predictor of long-distance running performance even in elite male runners with similar performance levels. Eleven highly-trained male long-distance runners participated in this study. The average running velocities of the individuals' running performance were 5.918 +/- 0.084 m.s-1 and 5.672 +/- 0.095 m.s-1 for 5000 m (V5000) and 10,000 m (V10000), respectively. The blood lactate concentrations and heart rate responses were measured immediately after field running, and the average value of running velocity corresponding to OBLA (VOBLA) was 5.447 +/- 0.132 m.s-1. Variations of these three velocities expressed as a coefficient of variance (CV) ranged from 1.4 to 2.4%. A strong inverse relationship between heart rate corresponding to OBLA (HROBLA) and performance was observed (r = -0.709, p < 0.02 for V5000 and r = -0.830, p < 0.01 for V10000), while there was a lack of significant relationship between VOBLA and performance (r = 0.293, NS for V5000 and r = 0.130, NS for V10000). Furthermore, the average value of HROBLA obtained in this study (174.5 +/- 8.2 b.min-1) was quite similar to that of the heart rate threshold reported by some previous researchers. In conclusion, VOBLA alone could not explain the small variation of long-distance running performance, and HROBLA should be used in place of VOBLA for evaluating long-distance running performance in elite runners with quite similar performance levels.

Adult↗
PubMed2006

Distance and flow effects on microsphere transport in a large gravel column.

Consumption of microbially contaminated ground water can cause adverse health effects and the processes involved in pathogen transport in aquifers need to be understood. The influences of distance, flow velocity, and colloid size on colloid transport were examined in homogenous pea-gravel media using an 8-m column and three sizes (1, 5, and 10 microm) of microspheres. Experiments were conducted at three flow rates by simultaneously injecting microspheres with a conservative tracer, bromide. Observed concentrations were simulated with CXTFIT and analyzed with filtration theory. The results demonstrate that colloid concentration is strongly log-linearly related to transport distance (as suggested by filtration theory) in coarse gravels, similar to our previous field studies. In contrast, the log-linear relationship is often reported to be invalid in fine porous media. The observed log-linear relationship is possibly because straining is negligible in the coarse gravels investigated. This has implications in predicting setback distances for land disposal of effluent, and suggests that setback distances in gravel aquifers can be estimated using constant spatial removal rates (f). There was an inverse relationship between transport distance and colloidal concentration, but not with temporal attachment rate (katt) and collision coefficient (alpha). Increases in flow velocity result in increasing colloidal recovery, katt and alpha but decreasing f. Increases in sphere size result in decreasing colloidal recovery with increasing katt, f, alpha, and velocity enhancement. Diffusion is the dominant collision mechanism for 1-microm spheres (81-88%), while settling dominates for 5- and 10-microm spheres (> 87%), and interception is very small for all spheres investigated.

Biological Transport↗
PubMed2006

High-resolution CT grading of tibial stress reactions in distance runners.

OBJECTIVE: The purpose of this study was twofold: to determine whether asymptomatic distance runners exhibit cortical tibial abnormalities on CT and to determine the diagnostic accuracy of CT in athletes with medial tibial stress syndrome. MATERIALS AND METHODS: A cross-sectional study with high-resolution CT of both tibiae was performed on 41 subjects: 20 asymptomatic distance runners, 11 distance runners with unilateral or bilateral pain due to medial tibial stress syndrome (14 painful tibiae), and 10 volunteers not involved in a sport. The group was composed of 13 women and 28 men, ranging in age from 18 to 26 years. A total of 82 tibiae, 14 painful and 68 painless, were evaluated. On the basis of CT findings, tibiae were classified in three groups, and correlation between CT classification and symptoms was made. RESULTS: Among distance runners, the presence of CT abnormalities was found in 14 (100%) of 14 painful tibiae in patients with medial tibial stress syndrome and in 8 (16.6%) of 48 painless tibiae. The difference was statistically significant (p < 0.001, Fisher's exact test). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT in diagnosing medial tibial stress syndrome were 100%, 88.2%, 63.6%, 100%, and 90.2%, respectively. CONCLUSION: High-resolution CT has high diagnostic accuracy in depicting medial tibial stress syndrome. Cortical abnormalities can also be seen in some asymptomatic distance runners.

Adolescent↗
PubMed1977

Effects of physical and phenomenological distance on self-disclosure.

This study was designed to investigate the effects of physical and phenomenological distance on self-disclosure. Two physical distances, culturally appropriate and culturally inappropriate, and three degrees of phenomenological closeness were selected. Differences in physical and phenomenological distances had significant effects upon the subjects' (n = 60) durations of self-disclosure. Subjects' feelings toward the experimenter and experiment were affected by differences in physical distance. No significant interactions between physical and phenomenological distance were evident.

Humans↗
PubMed1981

Some factors influencing perceived goal distance in time: a preliminary check.

Perceived goal distance in time (PgD) is assumed to be influenced by (a) physical distance in time, (b) the individual's future-time orientation (FTO), (c) perceived intrinsic instrumentality of activity (PiI), and (d) the importance of the goal. The results, based on pupils (159 boys and 151 girls) in Grades 7, 8, and 9, showed that pupils high in future-time orientation (FTO) and perceived intrinsic instrumentality of activity (PiI), perceived any temporal distance (PgD) as shorter than those who were low in these variables. However, the most significant determinant of perceived goal distance in time (PgD), in addition in physical distance in time, was the importance of the future goal; a very important goal being perceived a much closer than an unimportant goal.

Achievement↗
PubMed1990

Validity of visually recorded temporal-distance measures at selected walking velocities for gait analysis.

The purpose of this study was to examine the validity of measures of temporal distance in a clinical analysis of gait. Data were collected from 15 normal subjects by one examiner. Equipment consisted of a 10-meter laminated walking track, dictaphone, metronome, and ink markers. The number of errors at four walking speeds were examined using a standardized analysis of gait. Analysis of variance showed a significant number of errors between the first and last halves of the measurement distance and among the four walking velocities. Post hoc analysis using the Scheffé test indicated significant differences in the mean number of errors at the velocities of 60 and 75 versus 25 and 40 m.min-1. An F test for simple effects indicated a significant number of errors occurred during the second half of the measured distance and at walking velocities of 60 and 75 m.min-1. These results indicate that the gait analysis is valid for measurements taken at all of the walking velocities only when recorded over a three-meter distance and only at the velocities of 25 and 40 m.min-1 over a six-meter distance.

Gait↗
PubMed1997

Relationship of swimming distance, expectancy, and performance to mood states of competitive athletes.

This study focused on the relationship between normal and abbreviated training sessions for young competitive swimmers and acute changes in mood. Several potential moderators of the relationship between exercise and mood also were examined. 25 girls and 23 boys, swimmers between the ages of 12 and 25 years, completed a shortened version of the Profile of Mood States before and after normal-distance and taper practices. An hypothesized interaction between distance training and acute changes in scores on Total Mood Disturbances was significant. During normal-distance practices, scores on Mood Disturbance increased from pre- to postpractice. Analyses of the individual subscales indicated that swimmers" scores increased for Fatigue and decreased for Vigor. In abbreviated practice sessions, athlete's scores on Total mood Disturbance showed no change from pre- to postpractice. The specific subscales, however, showed positive changes for Depression, Confusion, and Tension. The mood changes related to practice distance were not influenced by the possible moderating factors of expectancy or performance times. Thus, even for highly trained competitive swimmers, exercising at or near maximal physical capability is associated with few positive changes in mood scores. Shorter-distance swims that do not tax endurance are preferable, if mood enhancement is a goal.

Adolescent↗
PubMed1998

Influences of long- and short-distance driving on alpha waves and natural killer cell activity.

We examined the effective amplitudes of alpha waves (using a mean frequency with a range of +/- 0.5 Hz), and activity of natural killer cells in six subjects, before and after a short-distance (43 km, 1 hr.) drive, and after a midnight (am 0:00-am 7:00 to 8:00) long-distance (550 km on average, for 7 to 8 hr.) drive. Following a long-distance drive, the activity of natural killer cells tended to decrease, and the effective amplitudes of alpha waves in the photic feedback period were greater than those observed during the rest period, showing that photic driving had occurred even under physically and mentally stressful conditions. However, after short-distance driving, no photic driving response occurred and activity of natural killer cells tended to increase, possibly related to mental concentration. Avoiding midnight long-distance driving may help prevent excessive stress and preserve high activity in natural killer cells.

Adult↗
PubMed1998

Communicating with elders: effects of speaker-listener distance.

As the distance between two communicators increases, weaker sounds of speech become inaudible, conversation becomes more difficult and there is a greater need to resolve communication difficulties. This study investigated the effects of distance on face-to-face social conversation by 27 older adults with hearing impairment, under three listening conditions (without amplification, with personal hearing aids, with a small portable amplifier). Each participant was rated on a 1-5 scale of conversational fluency at distances between 0.5 and 3.0 metres. Results indicate that the subjects conversed more fluently with amplification and at short communication distances. Use of a portable amplifier resulted in high conversational fluency regardless of distance.

Aged↗