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PubMedDate not supplied

Prism adaptation for esotropia with a distance-near disparity.

A series of 64 patients who had surgery for esotropia with a distance-near disparity of at least 10 prism diopters was reviewed. Thirty-three patients were prism adapted for their distance deviation (PA distance). Thirty-one patients were prism adapted for near deviation (PA near). Both groups were divided into responders and nonresponders. In the PA distance group, 22 (67%) patients were responders. All responders had surgery for their prism-adapted angle. Postoperatively, 19 (86%) responders had fusion. Thirteen (68%) required bifocals to maintain fusion. In the PA near group, 21 (68%) patients were responders. All responders had surgery for their prism-adapted angle. Ninety-four percent of responders had fusion postoperatively. None needed bifocals for fusion postoperatively and none were overcorrected. The results show that those patients who were prism adapted for their near angle, responded with fusion, and had surgery for their full amount of esotropia at prism response obtained better postoperative fusion, without the need for a bifocal at near and without overcorrection at distance.

Adaptation, Ocular↗
PubMed1997

[The effects of a fimbria-fornix lesion on distance discrimination in rats].

In order to study the role of hippocampus in spatial learning, fimbria-fornix (FF) lesioned and control rats, eight each, were trained for a distance discrimination task in a rectangular test box (120 x 60 x 35 cm). A rat was placed in a start box at one of the corners of the test box, and then released to choose the bottle that contained food reward. Two bottles, at the distance of 50 cm, were placed along the walls, one short and the other long, on either side of the start box, and to find the reward the rat had to discriminate the distance, i.e., short vs. long wall of the test box. Results showed that control rats were able to make the discrimination, while FF rats were not. The finding suggests that hippocampus plays an important role in processing distance information in general, and distance discrimination in particular.

Animals↗
PubMed1988

Application of an Euclidian distance measure to the selection of reference areas in epidemiologic research concerning environmental issues.

A procedure for selecting reference areas in epidemiologic research employing census data and squared Euclidian distance is described. The procedure was adapted from cluster analysis, a multivariate statistical technique that has been applied in many disciplines. With the use of 12 census variables as the basis for evaluating sociodemographic differentiation, squared Euclidian distances were calculated between a geographically delineated index area in southwest Alberta, where residents had complained for several years about the effects of exposure to sour gas emissions, and 119 provincial census tracts in the rest of nonmetropolitan southern Alberta. The Euclidian distances can be interpreted as social distance scores with values close to zero representing a high level of sociodemographic similarity between the index area and potential reference areas. The social distance scores, in association with environmental data, suggested a clear choice for the most comparable unexposed reference area and illustrated the difficulty of finding a suitable most comparable exposed reference area. Results from the demographic component of the subsequent health survey indicated that the index area and reference area were similar in most respects. Furthermore, tests with and without statistical adjustment for confounding variables produced negligible differences on most of the important target outcome variables.

Adolescent↗
PubMed2006

The basis for prescribed ability group run speeds and distances in U.S. Army basic combat training.

During the first few days of Army Basic Combat Training (BCT), recruits take a running test and after completing this test they are ranked from fast to slow. Four roughly equal-sized "ability groups" are established from these rankings and recruits run together in these groups for their physical training during BCT. In the past, there has been no formal guidance regarding how fast or how far these ability groups should run. To fill this void, this study provides guidance for running speeds and distances during BCT. The major considerations included are: (1) minimizing injuries, (2) the initial aerobic fitness level of recruits, (3) historical improvements in run times during BCT, (4) historical running speeds of the slower individuals in each ability group, (5) running speeds that must be achieved to "pass" the 2-mile run in BCT, (6) the gender composition of the ability groups, and (7) recommendations from the trainers and field testing. Three databases were analyzed that contained a total of 16,716 men and 11,600 women. Four steps were used in the analyses: (1) establishment of run-time cut points for representative ability groups, (2) determination of initial (starting) run speeds, (3) estimation of changes in run speeds with training, and (4) establishment of run speeds and distances for each week of BCT. Efforts were made to (1) keep the running speeds between 70% and 83% of the estimated maximal oxygen uptake (VO2max) for all ability groups, (2) consider the 2-mile running pace of the slower individuals in each ability group, and (3) keep the total running distance for the two slower ability groups below a total of 25 miles, the apparent threshold for increasing injury incidence. A chart provides speeds and distances for each ability group at each week of BCT. Using these recommended speeds and distances should allow trainees to improve their aerobic fitness, pass the Army Physical Fitness Test, and minimize injuries that result in lost training time and, ultimately, lower fitness levels.

Adolescent↗
PubMed1999

The radial distance of extraprostatic extension of prostate carcinoma: implications for prostate brachytherapy.

BACKGROUND: Extraprostatic extension (EPE) is an unfavorable prognostic factor in patients with prostate carcinoma. Prior studies have reported the linear extent of EPE measured circumferentially along the edge of the prostate. In this study, the authors defined and evaluated a novel measure of EPE in a large series of radical prostatectomy specimens. These results have important clinical implications in the management of localized prostate carcinoma by brachytherapy and other modalities. METHODS: The authors reviewed the preoperative records and biopsy findings from 376 patients who underwent radical retropubic prostatectomy between September 1991 and June 1993. Whole mount radical prostatectomy specimens were examined, and the location of EPE for each specimen was recorded. The radial EPE distance was measured perpendicular to the edge of the prostate. For specimens with multiple EPE sites, the maximum radial EPE distance was recorded. Established eligibility criteria for prostate brachytherapy were evaluated using these results, with emphasis placed on achieving adequate radiation dose coverage 3-5 mm beyond the capsule or the edge of the prostate. RESULTS: EPE was identified in 105 of 376 specimens (28%) at 248 sites. The radial EPE distance in these specimens had a mean of 0.8 mm (range, 0.04-4.4 mm) and a median of 0.5 mm. Of these 105 patients, the median and mean preoperative prostate specific antigen (PSA) concentrations were 11.8 ng/mL and 17.9 ng/mL, respectively. The mean and range of the Gleason score and prostate volume for all specimens were 6.3 (range, 3-9) and 39 cc (range, 8-294 cc), respectively. In 107 patients who met the selection criteria for prostate brachytherapy eligibility of a PSA level < 10 ng/mL, Gleason score < 7, and gland volume < 60 cc, the maximum and mean radial EPE distances were 0.6 mm and 0.03 mm, respectively. CONCLUSIONS: The radial distance of EPE is an important measure that influences treatment strategies for patients with localized prostate carcinoma. Currently described criteria for the treatment of early stage prostate carcinoma by brachytherapy alone appear satisfactory to ensure effective radiation dose coverage of EPE of prostate tumors. Treating the prostate with a 3-5 mm margin by brachytherapy would encompass all known tumor in approximately 99% of the specimens examined in this study.

Aged↗
PubMed2000

[Results of implantation of endocapsular distance rings].

Endocapsular distance ring increases possibilities of extraction subluxated cataract. Its importance consists of stabilisation of capsular bag and with the possibility of implantation posterior intraocular lens. In the group there are 20 patients with implanted 21 distance rings. The period of follow up was 4-24 months. We used of a polymethyl methacrylate distance ring from firms Erilens, Morcher and IOLTechnology. Indication for the implantation of a distance ring was dialysis less than 2 quadrants, it depends on size and type of distance ring. The authors evaluate complications during the operation and early and later results after operation.

Cataract Extraction↗
PubMed2000

Improvement of walking distance by defibrotide in patients with intermittent claudication--results of a randomized, placebo-controlled study (the DICLIS study). Defibrotide Intermittent CLaudication Italian Study.

Defibrotide is an antithrombotic drug which enhances prostacyclin production and activates fibrinolytic system. The aim of this study was to investigate the improvement of walking distance in patients with intermittent claudication treated with defibrotide. DICLIS was a double blind, placebo-controlled study which included patients with walking distance autonomy at a standardized treadmill test < or =350 > or =100 meters. A total of 310 patients were randomly allocated to placebo (n = 101), defibrotide 800 mg/day (n = 104) or defibrotide 1200 mg/day (n = 105). During a one year follow-up, the Absolute Walking Distance (AWD) was measured six times (0, 30, 60, 90, 180, 360 days). Similar improvement in walking distance was found in the three groups until the 90th day; thereafter placebo group showed no further increase, while AWD continued to increase in the defibrotide groups. Between the 180th and 360th day visits, AWD was significantly higher (P <0.01) in patients given defibrotide than in patients given placebo. No difference in efficacy was observed between the two dosages of defibrotide. No differences in side effects were observed among the three groups. The results of the present trial suggest that long-term administration of defibrotide improves walking distance in patients with intermittent claudication.

Adult↗
PubMed2001

Expression and meaning of medical language: building an epistemological framework for the study of semantic distance.

The use of language for communication purposes introduces a semantic gap in data processing. We have developed a new tool called semantic distance to overcome this gap. A previous presentation of our tool was based on an empirical approach. Here, we examine the properties and theoretical foundation of semantic distance from a rationalistic perspective. We present an epistemological framework to explain the meaning of semantic distance. As a tool, the purpose of semantic distance is the exchange of data or knowledge based on linguistic expressions between software components. We propose a review of the relationship between language and its representation for data processing based on the underlying philosophical assumptions. Description logic is a new paradigm in the medical informatics community to express relations between terms in "is-a" hierarchies. The utility of semantic distance is compared to description logic for communication purposes in different use cases.

Knowledge↗
PubMedDate not supplied

Children with non-verbal learning disabilities (NLD): coherence values in the resting state may reflect hypofunctional long distance connections in the right hemisphere.

EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency windows between 1 and 51 Hz were studied in 18 children with "non-verbal learning disorder" (NLD) and compared to a group of 18 children with "verbal learning disorder" (VLD). New facts were found in the NLD group. These concern hemispheric balance, expressed as left minus right (L-R) homologous HCohs: 1a). In the high frequencies (25-51 HZ) the number of long-distance HCohs, higher in the right hemisphere (RH), is lower than HCohs, which are higher in the left hemisphere (LH). A reversed interhemispheric asymmetry is seen for short distance HCohs in that band. These asymmetries are not found in the VLD group, and the tendency is even reversed. 1b). In the low frequencies (1-27 Hz) all higher HCohs are more numerous in the RH, irrespective of interelectrode distance (IED). In these bands there are no NLD-VLD group differences; 2). In NLD there is a significant inverse relationship between IED and (L-R)HCoh values (designated as LRDif) in the high frequencies: the larger the IED, the higher the LRDif. In the lower frequencies there is no such tendency. In the VLD group these relationships were absent. These preliminary results suggest long distance gamma band hypoconnectivity in the RH of NLD children, in line with the hypothesis of an RH long distance connectivity problem in NLD. This may explain difficulties with mtermodal perception (gestalt function). Finally in the NLD group some gamma band interhemispheric (ICohs) over F7/F8 and T3/T4 were lower than in VLD children and some gamma band ICohs were higher in NLD compared to VLD over O1/O2. This is possibly connected with the cognitive differences subserved by these areas, i.e., language, respectively visuospatial function.

Cerebral Cortex↗
PubMed2000

[Comparative study of technique of laser welding ceramo-alloy by different gap distance].

OBJECTIVE: To investigate the quality of laser welded non-precious base alloy by different gap distance and its clinic probability. METHODS: Laser welded ceramo-alloy CW-PA specimens by different gap distance of 0.0 mm, 0.25 mm, 0.5 mm, Tested joined sample's UTS, microhardness; took SEM examination on its tensile fracture surface and metallographic examination on longitudinal cross section. RESULTS: The study showed that UTS of Laser welded CW-PA by different gap distance of 0.0 mm, 0.25 mm, 0.5 mm is (446.05 +/- 82.50) MPa, (485.97 +/- 62.35) Mpa, (503.32 +/- 65.79) MPa respectively, approach to original rod (421.53 +/- 21.78) MPa (P > 0.05). Microimage at tested samples of gap distance at 0.0 mm, 0.25 mm are good. CONCLUSION: It revealed that 1. Laser welding specimen should be contacted as close as possible 2. The gap distance should be less than 0.5 mm, 0.25 mm is better, and easy to handle.

Dental Soldering↗
PubMed2002

Is the distance a patient lives from hospital a risk factor for death from tuberculosis in rural South Africa?

SETTING: Tuberculosis programmes that rely on district hospitals for diagnosis and initiation of treatment may disadvantage those living furthest away. We present an analysis of such a programme in rural South Africa to see whether those living furthest from the hospital were at greatest risk of dying from tuberculosis. METHODS: All patients diagnosed and treated for tuberculosis in three health districts in 1997 and 1998 were included. An estimate of the distance each patient travelled to get to the hospital was obtained. The distances the patients travelled were categorised into four groups. The furthest distance patients could reasonably be expected to travel to get to their nearest hospital was estimated as 60 km. Outcomes of treatment were recorded using standard definitions. The mortality of patients in each of the four groups was compared. RESULTS: Of 1187 patients started on treatment for tuberculosis in the hospitals, 877 (74%) were known to be alive at the end of treatment, whereas 158 (13%) had died. Distance travelled was a risk factor for death, but only amongst those travelling more than 60 km to get to the hospital (0-20 km: n = 313, odds ratio [OR] 1; >20-40 km: n = 436, OR 1.09, 95% confidence interval [CI] 0.71-1.67; >40-60 km: n = 205, OR 0.97, 95%CI 0.57-1.65; >60 km: n = 79, OR 2.87, 95%CI 1.59-5.17). CONCLUSION: The mortality from tuberculosis was high, even amongst those living closest to the hospital, and did not rise significantly within 60 km. The situation may be different for the relatively small number of patients who come from further away. The distance travelled to hospital for initial diagnosis does not account for the relatively high mortality amongst tuberculosis patients in this area.

Adolescent↗
PubMedDate not supplied

An epidemiological study evaluating the relationship of distance from a tertiary care cancer center to early detection of colorectal carcinoma.

OBJECTIVE: AJCC stage at diagnosis determines the treatment approach and indirectly predicts outcome in patients with colorectal carcinoma. The purpose of our study was to investigate whether there was a delay in diagnosis leading to a more advanced stage at diagnosis (which affects outcome) of patients with colorectal cancers because of distance from a referral center, after positive fecal occult blood testing (FOBT). DESIGN: Our retrospective observational study involved all cases of colonic and rectosigmoid cancers that were referred for an endoscopic procedure after an initial positive FOBT done as a part of routine screening in asymptomatic patients. PARTICIPANTS: Roger Maris Cancer Center and University of North Dakota School of Medicine and Health Sciences. RESULTS: Between the years 1996-2001, 178 subjects with biopsy-proven colon cancer and 80 patients with rectosigmoid cancer were included in our study. Pearson's correlation coefficients were constructed to look at the relationship between distance from a referral center (place where the diagnosis was made) and stage at diagnosis in patients with colonic and rectosigmoid malignancies. For the colon cancer group, the regression coefficient between AJCC stage at diagnosis and distance from the referral center was 0.013 and for rectosigmoid cancers it was 0.12. Even after stratifying distances into tertiles, the correlation coefficients did not show a significant relationship (0.04 for colon and 0.16 for rectosigmoid cancers). CONCLUSION: Distance (of residence) from a tertiary care center does not seem to be a barrier to early diagnosis of colorectal carcinoma and primary care providers in rural settings are referring patients appropriately leading to optimal outcomes.

Aged↗
PubMed2002

[Value of long-distance fetal heart rate monitoring on the pre-partum health care of the pregnant woman with umbilical cord loops].

OBJECTIVE: To explore the value of the long-distance fetal heart rate (FHR) monitoring on the pre-partum health care of self-monitoring at home for pregnant woman with the umbilical cord loops. METHODS: The umbilical cord loops was diagnosed by ultrasonography. In the study group, 896 pregnant women with the umbilical cord loops accepted long-distance FHR monitoring and the count of fetal movement (FM) as family-self monitoring methods, while in the control group, 1 914 pregnant women with the umbilical cord loops used the count of FM only as family-self monitoring method. Abnormal non-stress test (NST), variable deceleration, fetal distress, neonate asphyxia, fetal death, stillbirth, operative delivery rate were analyzed between the study and control group retrospectively. RESULTS: The incidence of NST reactive pattern and non- reactive pattern and the variable deceleration in long-distance FHR monitoring of the study group were significantly higher than those in routine FHR monitoring. The incidence of fetal distress in the study group (35.0%) was significantly higher than that in the control group (30.9%), while the incidence of neonatal asphyxia in the study group (3.5%) was significantly lower than that in the control group (5.6%). The incidence of outside hospital fetal death in the study group (0.1%) was significantly lower than that in the control group (0.8%). There were no significant differences of cesarean section rate, forceps or vacuum extractor delivery between the two groups (P > 0.05). CONCLUSIONS: This study suggested that the high variable rate in the long-distance FHR monitoring curve was related to the incidence of the fetal distress. It didn't increase the cesarean section rate and vaginal operative delivery rate, but decreased the neonatal asphyxia and outside hospital fetal death rate. The long-distance FHR monitoring combined with the count of FM may be a better family-self monitoring method for the pregnant women with the umbilical cord loops.

Cesarean Section↗
PubMed2003

The effect of leaf width and sampling distance on the "stair-stepping" of field borders defined by multileaf collimators.

Standard multileaf collimators (MLCs) are now available with 1.0 and 0.5 cm leaf widths. The aim of this work is to compare the dose-undulation and effective penumbra of field edges formed by these MLC leaf widths and to determine how reducing the sampling distance (centre-to-centre distance between adjacent MLC leaves) for the 1.0 cm leaf width compares to the smaller leaf width. The undulation of the 50% isodose line and the 80-20% and 80-30% effective penumbra were compared for a field edge angled at 45 degrees to the MLC leaf motion direction at 8 cm depth. The larger leaf width field was also segmented to form field edges with 0.5, 0.33 and 0.2 cm sampling distance. Random setup variation of 2 mm standard deviation was also incorporated. Dose undulation was 1.5 mm for the 0.5 cm MLC leaf width compared to 4.5 mm for the 1.0 cm width. The 80-20% effective penumbra was 2 mm less for the 0.5 cm leaf width and the 80-30% effective penumbra was approximately 3 mm less. When random setup variation was incorporated the 0.5 cm leaf width isodoses were straight compared with approximately 3 mm undulation for the larger MLC. Reducing the sampling distance for the 1.0 cm MLC leaf width to 0.33 cm resulted in penumbra only slightly greater than the 0.5 cm leaf width and removed the undulation. Effective penumbra and dose undulation are reduced for the 0.5 cm leaf width compared to a 1.0 cm leaf width. Reducing the sampling distance for the 1.0 cm MLC leaf can approximate the 0.5 cm leaf width, at the expense of longer treatment times, and increased quality assurance investment.

Computer Simulation↗
PubMedDate not supplied

Effect of new dentures on interocclusal distance during speech.

PURPOSE: The aim of this study was to investigate the changes in interocclusal distance during the pronunciation of /m/ and /s/ sounds in the Portuguese language, in partially edentulous patients before and after insertion of new dentures. MATERIALS AND METHODS: Subjects were divided into a control group consisting of 18 completely dentate patients and an experimental group consisting of 18 patients who were edentulous in the maxilla and classified as Kennedy Class I in the mandible. The experimental group had new dentures placed and the occlusal vertical dimension corrected. A magnetic jaw-tracking device measured the interocclusal distance during pronunciation of the /m/ and /s/ phonemes. Interocclusal distance evaluations were carried out in a single session for the control group. In the experimental group, the measurements were carried out before insertion of new dentures; immediately after insertion; and after 6 and 24 hours; 2 days; 1 and 2 weeks; 1, 2, 3, and 6 months; and 1 year. RESULTS: Comparison between groups revealed significant difference in interocclusal distance for the /m/ sound both before and after insertion of dentures up to 2 months. For the /s/ phoneme, there was no difference between the groups before prosthesis insertion, or after 3, 6, and 12 months of prosthesis use. There were significant differences for the /m/ sound only at 6 and 12 months after new denture insertion, and for the /s/ sound at all periods evaluated. CONCLUSION: Insertion of new dentures, with the vertical dimension corrected, changes the interocclusal distance of speech during phonation of /m/ and /s/ sounds.

Adult↗
PubMed2004

A comparison of different heterogeneous proximity functions and Euclidean distance.

Proximity functions evaluate distances or similarities between objects. Unlike the Euclidean distance, heterogeneous proximity functions process variables differently according to their scale. The correct evaluation of nominal variables, whose values are unordered, is especially important. We compared five heterogeneous functions with the Euclidean distance to study whether functions sensitive to scale are better than a function assuming the same scale. In addition, we were interested of the relative performance of the five heterogeneous functions. The performance of the functions was measured with a nearest neighbor classifier that was applied to 12 medical data sets characterized with different scales. Unexpectedly, the performance of heterogeneous functions did not differ significantly from that of the Euclidean distance. As expected, significant differences between the Heterogeneous Value Difference Metric (HVDM) and the four value-matching-based heterogeneous functions favored HVDM. Additional research is needed to explain why heterogeneous functions did not outperform the Euclidean distance.

Artificial Intelligence↗
PubMed2002

On distance computation in space of mixed-type variables in medical data mining.

In the next study we consider two distance metrics that were presented in the machine leaming literature for mixed-type variables. We show that they are not really metrics, but pseudometrics. The problem arose from missing values. The metrics can be redefined to satisfy the metricity definition. Distance computation can then be performed reliably without a possibility that a distance between exactly similar patient cases would not be zero. We experimented with both procedures and so-called ignore mode using two medical data sets and observed that the redefined procedure was as good as the original approach as measured with the classification ability of one-nearest neighbour searching. It is noticeable that the described problem caused by missing values can be with any distance measure if its missing values are treated in the pessimistic manner as in the original version of these distance measures.

Computer Simulation↗
PubMedDate not supplied

[Expert evaluation of the gunshot distance based on the volume of wound canal in flat bones].

Different-distance experimental shots were made from a rifled gun at flat bones. Those shot distances were established, at which the wound canal had the smallest volume, and, at which entry and exit holes were virtually identical and matched the bullet diameter. A bigger shot distance was associated with an increasing volume of the wound canal caused by a bigger exit hole. A smaller shot distance led, also, to an increasing volume of the wound canal caused by bigger entry and exit holes. The volume of the wound canal in flat bones can be used as a reliable criterion in assessing the shot distance.

Bone and Bones↗