Inclination Measurements Research Articles

Caracterização postural da jovem praticante de ginástica olímpica

Postural characterization of young participants in Olympic gymnastics Objective: To identify the postural alterations among children aged 8 to 12 years who perform Olympic gymnastics. Method: Eighty-four students aged 8 to 12 years were assessed: 38 who were participating in Olympic gymnastics and 46 who were not. Each child was photographed in the anterior and posterior frontal planes and in the sagittal plane. The photos were analyzed using the CorelDraw v. 11.0 software. The line-guide and dimension tools (angular, vertical and horizontal dimensions) were used to determine the parameters of the nineteen qualitative and five quantitative variables. Results: Comparison between the test group subjects (TG) and control group subjects (CG) showed significant differences in the variables of medial rotation of the femur (CG 56.52%; TG 39.47%), antepulsion of the pelvis (CG 43.48%; TG 76.32%) and trunk rotation (CG 67.39%; TG 23.68%). There were also found significant differences in the measurements of knee valgism (CG 4.06 ± 2.32 cm; TG 3.14 ± 1.49 cm), pelvic inclination (CG 0.69 ± 0.39 cm; TG 0.53 ± 0.33 cm) and tibiotarsal angle (CG 86.93 ± 2.90 cm; TG 87.11 ± 4.17 cm). Conclusion: Analysis of the results showed a tendency towards better alignment of the lower limbs in the test group than in the control group. There was greater anterior pelvic inclination and a tendency towards lumbar hyperlordosis in the test group. These factors may predispose individuals participating in Olympic gymnastics to misalignment of skeletal structures, thereby leading to painful conditions that may limit their sports activities.

Cephalometric Assessment of the Axial Inclination of Upper and Lower Incisors in Relation to the Thirdorder Angle

Estimating incisor inclination cephalometrically by reference lines NA and NB puts the orthodontist in the difficult position of relating these axial inclination data to the bracket's third-order prescription which refers to a perpendicular to the occlusal plane. Purpose of the present study was to evaluate the relationship between the cephalometrically-assessed incisor inclination (using the lines NA and NB for reference) and the third-order angle (syn.: torque angle, TA) according to Andrews' description, and moreover to investigate the correlation between incisor inclination data and skeletal-sagittal and skeletal-vertical findings. The lateral cephalograms and corresponding dental casts of 67 subjects between 10 and 25 years of age (regardless of skeletal and dental relationships) were considered in the study. All subjects were Caucasian, and none had undergone orthodontic therapy. Upper (U1) and lower (L1) incisor angulations were cephalometrically assessed in reference to the NA and NB lines and compared to third-order angles obtained from dental cast measurements with an incisor inclination-recording appliance. Incisor inclination data from the two measurements were correlated to craniofacial sagittal (angles SNA, SNB, ANB) and vertical (angles NSL-NL, NSL-ML, ML-NL) findings from the radiographs. The third-order angles in the upper arch measured on the dental casts were a mean of 16.2 degrees (SD = 5.3 degrees) smaller than the axial inclination according to the NA line; the lower incisor third-order data were less than those of the axial inclination according to the NB line by a mean of 27.8 degrees (SD = 4.75 degrees). In this sample, there was a range of 42.7 degrees for the U1TA variable (mean = 5.6 degrees, SD 9.73 degrees) and 47 degrees for U1NA/ degrees variable (mean = 21.71 degrees, SD = 8.67 degrees). The L1TA variable showed a range of 29 degrees (mean = -2.95 degrees, SD = 7.17 degrees), the radiographic L1NB/ degrees range was 23 degrees (mean = 24.91 degrees, SD = 5.8 degrees). We observed a highly significant correlation (r(NA) = 0.84***, r(NB) = 0.76***) between the Andrews' angle and the inclination estimated in reference to the NA and NB lines. No significant correlation between incisor inclination and craniofacial measurements was detected. Dental cast measurements seem to be more precise and more valid than lateral radiographs. The method we describe enables clinicians to get a good idea precisely and quickly of how much torque potential remains in the brackets and archwires during treatment. The inclination of the incisors can also be calculated using the regression equations provided, making additional lateral cephalograms unnecessary.

Comparison of fluoroscopic and imageless registration in surgical navigation of the acetabular component

Objective: This study compared the repeatability and reproducibility of acetabular component positioning using imageless and fluoroscopic-referenced navigation methods.Methods: A single cadaveric pelvis had a modular acetabular component securely fixed. Cup position was evaluated using imageless and fluoroscopic registration techniques. These were compared to measurements of a coordinate measuring machine (CMM) and a validated CT scan protocol.Results: The CMM-determined anatomical acetabular inclination measurement was 46.02° (SD = 1.07), while the CMM-determined anatomical anteversion (pubic symphysis) was 15.79° (SD = 0.41). Computed tomography revealed inclination of 42.2° (SD = 0.65); anteversion with pubic tubercle referencing of 12.1° (SD = 0.14); and anteversion with pubic symphysis referencing of 14.3° (SD = 0.89). Evaluation of repeatability (one surgeon; n = 8) with the imageless system (pubic tubercle) revealed inclination of 41.8° (SD = 0.46) and anteversion of 11.2° (SD = 0.8). For the fluoroscopic system (pubic symphysis), inclination was 42.8° (SD = 1.6) and anteversion was 17.6° (SD = 3.1). Evaluation of reproducibility (three surgeons; n = 24) with the imageless system revealed inclination of 41.8° (SD = 0.82) and anteversion of 15.2° (SD = 1.06). For the fluoroscopic system, inclination was 48.5° (SD = 0.9) and anteversion was 17.8° (SD = 2.5). Imageless referencing of cup inclination and anteversion were found to be process capable using the Six Sigma Cp and Cpk capability indices. Fluoroscopic referencing was process capable for cup inclination but not for cup anteversion (Cp − 1.1; Cpk − 1.0). An F-test revealed significantly greater variance with fluoroscopic referenced anteversion (p < 0.002).Conclusions: Imageless referencing was process capable for computer navigation of cup placement in the ex-vivo setting. Fluoroscopic referencing for pelvic landmarks is problematic as locating points from radiographic images is difficult, especially for cup anteversion.

X ray measurement of the pelvic inclination

X ray measurement of the pelvic inclination

Comparison of fluoroscopic and imageless registration in surgical navigation of the acetabular component

Objective: This study compared the repeatability and reproducibility of acetabular component positioning using imageless and fluoroscopic-referenced navigation methods.Methods: A single cadaveric pelvis had a modular acetabular component securely fixed. Cup position was evaluated using imageless and fluoroscopic registration techniques. These were compared to measurements of a coordinate measuring machine (CMM) and a validated CT scan protocol.Results: The CMM-determined anatomical acetabular inclination measurement was 46.02° (SD = 1.07), while the CMM-determined anatomical anteversion (pubic symphysis) was 15.79° (SD = 0.41). Computed tomography revealed inclination of 42.2° (SD = 0.65); anteversion with pubic tubercle referencing of 12.1° (SD = 0.14); and anteversion with pubic symphysis referencing of 14.3° (SD = 0.89). Evaluation of repeatability (one surgeon; n = 8) with the imageless system (pubic tubercle) revealed inclination of 41.8° (SD = 0.46) and anteversion of 11.2° (SD = 0.8). For the fluoroscopic system (pubic symphysis), inclination was 42.8° (SD = 1.6) and anteversion was 17.6° (SD = 3.1). Evaluation of reproducibility (three surgeons; n = 24) with the imageless system revealed inclination of 41.8° (SD = 0.82) and anteversion of 15.2° (SD = 1.06). For the fluoroscopic system, inclination was 48.5° (SD = 0.9) and anteversion was 17.8° (SD = 2.5). Imageless referencing of cup inclination and anteversion were found to be process capable using the Six Sigma Cp and Cpk capability indices. Fluoroscopic referencing was process capable for cup inclination but not for cup anteversion (Cp − 1.1; Cpk − 1.0). An F-test revealed significantly greater variance with fluoroscopic referenced anteversion (p < 0.002).Conclusions: Imageless referencing was process capable for computer navigation of cup placement in the ex-vivo setting. Fluoroscopic referencing for pelvic landmarks is problematic as locating points from radiographic images is difficult, especially for cup anteversion.

3-D tracking of sperm whale dive profiles from a towed hydrophone array in ray-refractive environments

During the past 3 years the U.S.-based Sperm Whale Seismic Study (SWSS) has supported the development of a mobile three-dimensional passive acoustic tracking system. Acoustic data were recorded on a single four-element wide-aperture hydrophone array, towed at 80–100-m depth. The array was subdivided into forward and rear two-element subarrays, separated by 200-m aperture. To fix a location of an impulsive sound, three quantities are measured: the time difference between direct-path arrivals on the forward and rear subarrays, the time difference between the direct and surface-reflected paths on the rear subarray, and the acoustic bearing measured on the rear subarray. These quantities, combined with independent measurements of hydrophone depths and cable inclination, are postprocessed using a matlab GUI into range-depth position fixes by implementing an efficient numerical procedure that uses precomputed look-up tables to account for ray-refraction effects caused by depth-dependent sound-speed profiles. The predicted time difference between the direct and surface-reflected paths on the forward subarray is compared with the measured data to adjust for array tilt and depth measurement error. A by-product of this processing is a semiautomated detector to detect distinctive creak sounds. [Work supported by the U.S. Minerals Management Service and the Industry Research Funders Coalition.]

Design and analysis of an optoelectronic inclinometer for simultaneous measurement of inclinations along two orthogonal directions

Conventional inclination measurement systems such as precision vials and capacitance measuring systems can measure inclination in only one direction at a time. We present what is believed to be a new optoelectronic system that can measure inclination angles along two orthogonal directions simultaneously by using a simple pendulum, two mirrors, a 2D position-sensing detector (PSD), and a laser diode. The light ray from the laser is projected onto a mirror that is fixed to a pendulum whose relative angle modifies in response to inclination changes of the inclinometer's housing. The light ray reflected by the mirror is sensed by the PSD, after which the signal can be interpreted by a PSD signal processor, recorded, or output to a computer. This study uses skew-ray tracing methodology to obtain implicit nonlinear system equations to model the relations of the relative inclination angles of the various components, PSD position, and world frame. A first-order Taylor series expansion is used to obtain a linear form of the system equations. To validate the proposed methodology, an actual prototype system is built and experimental results show that the performance of this system is excellent.

Analysis of sensor platform dynamics in ground vehicle

A vehicular platform's dynamical behavior is analyzed as a basis for designing a laboratory test apparatus and an associated 2-dimensional orthogonal stabilizer. The test track caused inclination in the front direction to vary from -6.5/spl deg/ to 7.2/spl deg/ and from -5.5/spl deg/ to 5.0/spl deg/ in the side direction. The maximum angular rate was 19.8 /spl plusmn/ 0.1/spl deg//s in the front direction within a bandwidth of 0-2.5 Hz and 14.4 /spl plusmn/ 0.05/spl deg//s in the side direction. The platform's natural frequency in the front direction was found to be 0.8-1.0 Hz. In the side direction the most significant rate values appeared within 0-4 Hz but the natural frequency did not wake. Inclination measurements were based on sensor fusion where the basic model of stochastic Kalman filtering was applied.

The relationship between the orientation of the glenoid and tears of the rotator cuff

Our aim was to determine the most repeatable three-dimensional measurement of glenoid orientation and to compare it between shoulders with intact and torn rotator cuffs. Our null hypothesis was that glenoid orientation in the scapulae of shoulders with a full-thickness tear of the rotator cuff was the same as that in shoulders with an intact rotator cuff. We studied 24 shoulders in cadavers, 12 with an intact rotator cuff and 12 with a full-thickness tear. Two different observers used a three-dimensional digitising system to measure glenoid orientation in the scapular plane (ie glenoid inclination) using six different techniques. Glenoid version was also measured. The overall precision of the measurements revealed an error of less than 0.6 degrees. Intraobserver reliability (correlation coefficients of 0.990 and 0.984 for each observer) and interobserver reliability (correlation coefficient of 0.985) were highest for measurement of glenoid inclination based on the angle obtained from a line connecting the superior and inferior points of the glenoid and that connecting the most superior point of the glenoid and the most superior point on the body of the scapula. There were no differences in glenoid inclination (p = 0.34) or glenoid version (p = 0.12) in scapulae from shoulders with an intact rotator cuff and those with a full-thickness tear. Abnormal glenoid orientation was not present in shoulders with a torn rotator cuff.

Reproducibility of jaw movements in patients with craniomandibular disorders

It has never been investigated, if mandibular movements of patients with craniomandibular disorders (CMD) result in a lower reproducibility of dynamic functional parameters which are used for the individual articulator setting. The aim of the present study was to compare the reproducibility of electronically registered functional parameters in patients with CMD and in a control group. Dynamic functional parameters were recorded in 30 patients and 30 volunteers with a computerized ultrasound system (ARCUSdigma). The whole registration was performed three times during one session and three times at a second session 1 week later. The horizontal condylar inclination in the patient group gave a standard deviation of 2.17 degrees +/- 0.95 degrees , indicating poorer reproducibility than in the volunteer group, for which the standard deviation was 1.37 degrees +/- 0.42 degrees . The reproducibility of measurements of the Bennett angle was also poorer in the patient group than in the volunteer group, with standard deviations of 1.70 degrees +/- 0.62 degrees and 1.22 degrees +/- 0.40 degrees , respectively. The standard deviations calculated for determination of incisal inclination during laterotrusion was 3.02 degrees +/- 1.49 degrees for patients and 2.30 degrees +/- 1.17 degrees for volunteers. The standard deviations for incisal inclination during protrusion was 2.02 degrees +/- 0.95 degrees for patients and 2.06 degrees +/- 1.82 degrees for volunteers. The reproducibility of measurement of horizontal condylar inclination, Bennett angle and incisal inclination during laterotrusion therefore showed significantly lower reproducibility in the patient group than in the volunteer group (P < 0.05). The overall reproducibility of the measurements was nevertheless good in both groups, with standard deviations under 3.1 degrees , so that an individual setting of an articulator seems useful even in patients with CMD.

Results of geomagnetic observations in Central Africa by Portuguese explorers during 1877–1885

In this short contribution, geomagnetic measurements in Central Africa made by Capelo and Ivens – two Portuguese explorers – during the years 1877 and 1885 are provided. We show the scarce number of geomagnetic observation in Africa compiled until now. These Portuguese explorers performed a considerable amount of measurements of geomagnetic declination (44 measurements), inclination (50) and horizontal component (50) of the geomagnetic field. We compared the results attained by these keen observers with those derived from the global geomagnetic model by Jackson et al. [Jackson, A., Jonkers, A.,Walker, M., 2000. Four centuries of geomagnetic secular variation from historical records. Philos. Trans. R. Soc. Lond. 358, 957–990].

Spondylolysis, spondylolisthesis, and lumbo‐sacral morphology in a medieval English skeletal population

The prevalence of spondylolysis and spondylolisthesis was studied in an adult skeletal series from a rural English medieval archaeological site. Attempts were made to evaluate the association of three aspects of lumbo-sacral skeletal morphology (pelvic incidence (a measure of the anterior inclination of the sacral table), lumbar transverse process width, and the presence of lumbo-sacral spina bifida occulta) with spondylolysis and spondylolisthesis. Results indicated a high prevalence of spondylolysis compared with a modern reference population, but few cases of spondylolisthesis were identified. Analysis of prevalence with respect to age suggests that in the study population, pars interarticularis defects generally formed late in the growth period or early in adult life. The study group showed a high mean pelvic incidence compared with modern Western Europeans, indicating a more steeply inclined sacral table, which may have elevated the risk of developing pars interarticularis defects. However, no statistically valid association could be demonstrated between the presence/absence of spondylolysis and pelvic incidence in the study material. There was no evidence for a link between lumbar transverse process index or lumbo-sacral spina bifida occulta and spondylolysis/spondylolisthesis. It is concluded that the potential role of lumbo-sacral morphology, as well as of activity regimes, should be considered when interpreting spondylolysis in paleopathological studies. If the frequency of spondylolysis is to some extent an indicator of past activity regimes, it may reflect lifestyle in younger individuals rather than in mature adults. Further work investigating the link between spondylolysis and lumbo-sacral morphological variables in premodern populations would be of value.

The Development of a Novel Optoelectronic Level

Conventional levels can be employed to measure just one dimensional inclinations each time, and are frequently used to measure inclination, straightness and flatness. There are two disadvantages when such levels are used to measure two dimensional inclinations (such as flatness): (1) two measurement steps are needed to measure two orthogonal directions in flatness; and (2) the two directions cannot be perfectly perpendicular to each other because of setting errors. This paper describes the development of a novel optoelectronic level which employs a simple pendulum, reflection mirror, 2D PSD and laser diode. In this system, a laser light is projected onto reflection mirror 1 which is fixed on a simple pendulum, and mirror 1 reflects the light to mirror 2 which is fixed on a fixture, and mirror 2 reflects the light to the 2D PSD. Thus, the inclination measurement result can be obtained from the output of the PSD. This paper establishes a novel system and describes the complete experiment. The A-axis rotation angle from approximately -1.3 to 1.3 degrees can be measured with an accuracy of 2 arc sec, and the B-axis rotation angle from approximately -1.7 to 1.7 degrees can be measured with an accuracy of 3 arc sec.

Peripheral nerve compression neuropathy after fractures of the distal radius

Sixty patients with unilateral distal radius fractures were managed conservatively. Clinical assessment included objective and subjective evaluations of the outcome of treatment. Radiographic evaluation included fracture classification using the AO/ASIF system and measurement of volar tilt, radial inclination and radial height shortening at the end of treatment. Clinical signs of carpal tunnel syndrome were confirmed electrodiagnostically in 12 patients (20%) during the recovery period. Each patient had electrodiagnostic studies of both upper limbs performed to confirm the diagnosis. The mean time between injury and the onset of symptoms was 10 months (range 6.5 weeks-27 months). A statistically significant correlation between the final clinical results of treatment and post-traumatic median nerve compression neuropathy was found, but the occurrence of the neuropathy correlated with neither fracture type nor with the final radiographic findings. No clinical signs of ulnar or radial nerve compression occurred in this study.

Three-dimensional passive acoustic tracking of sperm whales (Physeter macrocephalus) in ray-refracting environments

A wide-aperture towed passive acoustic array is used to obtain ranges and depths of acoustically active sperm whales in the Gulf of Mexico in June 2004, by extending a technique previously reported [Thode, J. Acoust. Soc. Am. 116, 245-253 (2004)] to explicitly account for ray-refraction effects arising from a depth-dependent sound speed profile. Under this expanded approach, three quantities are measured from an impulsive sound: the time difference between direct-path arrivals on a forward and rear subarray, the time difference between the direct and surface-reflected paths on the rear subarray, and the acoustic bearing measured on the rear subarray. These quantities, combined with independent measurements of hydrophone depths and cable inclination, are converted into range-depth position fixes by implementing an efficient numerical procedure that uses a ray-tracing code to account for ray-refraction effects caused by depth-dependent sound speed profiles. Analytic expressions that assume a constant waterborne sound speed are also derived. Foraging depths of various sperm whales over 10 days in June, 2004 are estimated using the numerical technique.

Paleosecular variations recorded by Holocene-Pleistocene sediments from Lake El Trébol (Patagonia, Argentina)

Paleomagnetic studies carried out on six cores from the bottom sediments from lake El Trébol, South Argentina are described. Measurements of directions declination and inclination ( D and I) and intensity of natural remanent magnetisation (NRM), magnetic susceptibility at low and high frequency (specific, X and volumetric, k), isothermal remanent magnetisation (IRM), saturation isothermal remanent magnetisation (SIRM), back field and anhysteric remanent magnetisation (ARM) were carried out. Stability of the NRM was investigated by alternating-field demagnetisation. Rock magnetic studies suggest that the main carriers of magnetisation are ferrimagnetic minerals, predominantly pseudo single domain magnetite. Records of NRM and k show a good correlation with the sedimentological description, and also with those of shorter cores previously studied. The tephra layers were identified from the lithologic profiles and also from the magnetic susceptibility logs. Due to their different chronological meaning and their rather bad behaviour as magnetic recorder, these layers were removed from the sequence and the gaps that were produced along the profiles by the removal were closed, obtaining a shortened depth. Radiocarbon age estimates from these cores and from earlier studies allow us to construct a paleosecular variation (PSV) record for the past 24,000 years. These results show good correlation with the previous one. The spectrum obtained from spectral analysis shows major peaks at periodicities of about 1150, 1500, 2490, 3630, 5240 and 11,810 years. Both clockwise and counterclockwise precession of the geomagnetic vector is evident from analysis of the Bauer plots, with a preponderance of clockwise movement.

Victor Ambros

Victor Ambros

Cluster vision of the magnetotail current sheet on a macroscale

With Cluster 2001–2003 observations at ∼20 RE downtail we determine the cross‐tail current sheet configuration via mapping of the neutral sheet positions and direct measurements of the sheet inclination. The warping effect tilts both flanks of the sheet up to 40° in the YZ GSM plane, while the gradual hinging effect tilts the sheet up to 10–20° roughly in the XZ plane. These findings are in agreement with the recent neutral sheet model of Tsyganenko and Fairfield (2004). Nonuniform response of the neutral sheet By to IMF was also revealed. Typical IMF By penetration efficiency was 40–60%. However, efficiency for positive IMF By was below 20% at both flanks. Therefore at the flanks of the neutral sheet the normal magnetic field component (along the normal to the warped sheet) is generally larger than the shear component (along the current).

Effects of Gravitational Lensing in the Double Pulsar System J0737-3039

We investigate the effects of gravitational lensing in the binary pulsar system J0737-3039. Current measurement of the orbital inclination allows the millisecond pulsar (A) to pass very close (at Rmin ≈ 4000 km) in projection to the companion pulsar (B), with Rmin comparable to the Einstein radius (≈2600 km). For this separation at the conjunction, lensing causes small (about 10%) magnification of the pulsar A signal on a timescale of several seconds and displaces the pulsar image on the sky plane by about 1200 km. More importantly, lensing introduces a correction (of several microseconds) to the conventional Shapiro delay formula used in pulsar timing analysis and gives rise to a geometric time delay together with the delays associated with the pulsar spin period. These lensing effects can influence the determination of the system parameters by both timing and scintillation studies. Given the current uncertainty in the orbital inclination, more extreme manifestations of lensing (e.g., magnification by a factor of several) are possible. We compare our predictions with the existing observations and discuss the possibility of detecting gravitational lensing signatures in the system. The anomalously high point in pulsar A's light curve close to superior conjunction might be caused by gravitational lensing.

312 ディジタルホログラフィによる棒状物体の姿勢計測(S42-2 流れの可視化実験解析(2),S42 流れの可視化実験解析)

This paper presents the measurement technique for detecting the inclination of slender object positioned in 3D space. The technique is based on digital holography and the inplane angle and depth angle are detected from the 3D volume of light intensity numerically reconstructed from an hologram pattern observed with an electronic camera. The two angles are determined based on the positions in depth measured for all parts of slender object in the technique. The accuracy of the present method in inclination measurement is evaluated in numerical simulation to show that the RMS error in depth angle is less than 1deg for the given angle of 45deg.