Height Discrepancy Research Articles

Quantifying Progressive Anterior Overgrowth in the Thoracic Vertebrae of Adolescent Idiopathic Scoliosis Patients: A Sequential Magnetic Resonance Imaging Study.

Anterior and posterior vertebral body heights were measured from sequential magnetic resonance imaging (MRI) scans of adolescent idiopathic scoliosis (AIS) patients and healthy controls. To measure changes in vertebral body height over time during scoliosis progression to assess how vertebral body height discrepancies change during growth. Relative anterior overgrowth has been proposed as a potential driver for AIS initiation and progression. This theory proposes that the anterior column grows faster, and the posterior column slower, in AIS patients when compared with healthy controls. There is a disagreement in the literature as to whether the anterior vertebral body heights are proportionally greater than posterior vertebral body heights in AIS patients when compared with healthy controls. To some extent, these discrepancies may be attributed to methodological differences. MRI scans of the major curve of 21 AIS patients (mean age 12.5 ± 1.4 years, mean Cobb 32.2 ± 12.8 degrees) and between T4 and T12 of 21 healthy adolescents (mean age 12.1 ± 0.5 years) were captured for this study. Of the 21 AIS patients, 14 had a second scan on average 10.8 ± 4.7 months after the first. Anterior and posterior vertebral body heights were measured from the true sagittal plane of each vertebra such that anterior overgrowth could be quantified. The difference between anterior and posterior vertebral body height in healthy, nonscoliotic children was significantly greater than in AIS patients with mild to moderate scoliosis. There was; however, no significant relationship between the overall anterior-posterior vertebral body height difference in AIS and either severity of the curve or its progression over time. Whilst AIS patients have a proportionally longer anterior column than nonscoliotic controls, the degree of anterior overgrowth was not related to the rate of progression or the severity of the scoliotic curve. 3.

The TanDEM-X DEM Mosaicking: Fusion of Multiple Acquisitions Using InSAR Quality Parameters

Since 2010, TanDEM-X and its twin satellite TerraSAR-X fly in a close orbit formation and form a single-pass synthetic aperture radar (SAR) interferometer. The formation was established to acquire a global high-precision digital elevation model (DEM) using SAR interferometry (InSAR). In order to achieve the required height accuracy of the TanDEM-X DEM, at least two global coverages have to be acquired. However, in difficult and mountainous terrain, up to five coverages are present. Here, acquisitions from ascending and descending orbits are needed to fill gaps and to overcome geometric limitations. Therefore, a strategy to properly combine the available height estimates is mandatory. The objective of this paper is the presentation of the operational TanDEM-X DEM mosaicking approach. In general, multiple InSAR DEM heights are combined by means of a weighted average with the height error as weight. Apart from this widely used mosaicking approach, one big challenge remains with the handling of larger height discrepancies between the input data, which are mainly caused by phase unwrapping errors, but also by temporal changes between acquisitions. In the case of inconsistencies, the TanDEM-X mosaicking approach performs a grouping into height levels. A priority concept is set up to evaluate the different groups of heights considering the number of DEMs and several InSAR quality parameters: the height error, the phase unwrapping method, and the height of ambiguity. This allows the identification of the most reliable height level for mosaicking. This fusion concept is verified on different test areas affected by phase unwrapping errors in flat and mountainous terrain as well as by height discrepancies in forests. The results show that the quality of the final TanDEM-X DEM mosaic benefits a lot from this mosaicking approach.

Retrospective study to determine the accuracy of template-guided implant placement using a novel nonradiologic evaluation method

With a novel, noninvasive method for determining three-dimensional accuracy, the realized implant position relative to the planned implant position was analyzed retrospectively. Additional postoperative cone beam computed tomography was thus dispensable. Twelve cases with distal extension situations (DESs) or single tooth gaps (STGs) were evaluated. The data sets of the planned implant position were superimposed on the actually achieved implant position, retrieved from digitizing the implant impression. The deviations were measured and statistically analyzed. The mean deviation was 5° in the DES group and 4° in the STG group for the implant axes, 1 mm (DES) and 0.9 mm (STG) at the implant neck, and 1.6 mm (DES) and 1.5 mm (STG) at the implant apex. The mean height discrepancy was 0.5 mm (DES) and 0.5 mm (STG). No significant differences (P > .05) were found between the DES and STG groups. The innovative, noninvasive evaluation method is suitable and sufficiently accurate for the assessment of larger cohorts. The results of our study showed a sufficiently high degree of accuracy when using a virtual planning program for which no radiopaque template is needed when performing cone beam computed tomography.

The Role of Resorbable Plate and Artificial Bone Substitute in Reconstruction of Large Orbital Floor Defect.

It is essential to reduce and reconstruct bony defects adequately in large orbital floor fracture and defect. Among many reconstructive methods, alloplastic materials have attracted attention because of their safety and ease of use. We have used resorbable plates combined with artificial bone substitutes in large orbital floor defect reconstructions and have evaluated their long-term reliability compared with porous polyethylene plate. A total of 147 patients with traumatic orbital floor fracture were included in the study. Surgical results were evaluated by clinical evaluations, exophthalmometry, and computed tomography at least 12 months postoperatively. Both orbital floor height discrepancy and orbital volume change were calculated and compared with preoperative CT findings. The average volume discrepancy and vertical height discrepancies were not different between two groups. Also, exophthalmometric measurements were not significantly different between the two groups. No significant postoperative complication including permanent diplopia, proptosis, and enophthalmos was noted. Use of a resorbable plate with an artificial bone substitute to repair orbital floor defects larger than 2.5 cm2 in size yielded long-lasting, effective reconstruction without significant complications. We therefore propose our approach as an effective alternative method for large orbital floor reconstructions.

Effect of Interface Trap States on Optical Barrier Height of NiSi/Si Infrared Detector

In this paper, influence of interface trap states on barrier height of NiSi/Si Schottky diode is presented. The proposed study is important in view of its application potential as an infrared detector. This involves preparation of silicide by depositing 10 nm thick nickel on n-Si, followed by rapid thermal annealing at 500 0C in argon ambience. The thickness of the silicide was measured by cross-sectional HRTEM and found to be 24 nm. The zero bias barrier heights were measured by current-voltage and optical techniques, and were found to be 0.62 eV and 0.54 eV respectively. This discrepancy in barrier height is attributed to the presence of acceptor like interface trap state which was identified by DLTS technique.

ALS model-based comparison of Cosmo-SkyMed and TerraSAR-X HS DSMs on varied land forms

Since 2007, the revolutionary X-band synthetic aperture radar (SAR) satellites Cosmo-SkyMed (CSK) and TerraSAR-X (TSX) have been collecting high-resolution images that are convenient for digital surface model (DSM) acquisition by the interferometric SAR (InSAR) technique. In this study, the potential of DSMs derived from CSK and TSX high-resolution spotlight (HS) images is thoroughly analysed regarding the basic accuracy metrics absolute vertical accuracy (AVA) and relative vertical accuracy (RVA). Utilising convenient InSAR pairs, 2 m gridded DSMs are generated in Istanbul and validated with model-based comparisons using an actual airborne laser scanning (ALS) DSM. Results show that CSK and TSX DSMs are compatible in open, built-up and forest land forms. The AVAs are between 8 m and 10 m based on standard deviation of height discrepancies against the ALS model. The RVAs, calculated by the coherence of neighbouring pixels for each DSM, are superior to AVAs for both CSK and TSX.

Evaluation of the various orthometric height systems and the Nigerian scenario – A case study of Lagos State

Though considered the easiest in 3-Dimensional Point Positioning, the choice of a height system especially in areas with spatially-vast land mass is rather a complicated choice. Orthometric heights are naturally and fully referenced to the actual earth gravity field but laborious to compute considering the required approximations of gravity variation along the plumb-line from the surface to the geoid. Normal heights on the other hand are less laborious to compute and do not require actual gravity observations. Unfortunately, natural height systems are the only systems that can efficiently predict fluid flows. This paper has therefore examined the theory and practical possibility of replacing the use of Helmert Orthometric Heights with Normal Orthometric heights within Lagos State. A maximum height discrepancy of 1mm was obtained in the comparison of both systems and thus their replaceability found suitable to within 3rd order geodetic accuracy.

Effects of Unequal Diffusion Coefficients and Coupled Chemical Equilibria on Square Wave Voltammetry at Disc and Hemispherical Microelectrodes

Square wave voltammetry (SWV) at disc and hemispherical microelectrodes is studied when the electroactive species show different diffusivities and/or take part in chemical equilibria in solution, under both transient and steady state conditions. Despite the use of microelectrodes, experiments in pulse techniques such as SWV frequently correspond to transient conditions since the pulse duration are typically very short (<100ms, f>5Hz). As will be shown, under such conditions the case of unequal diffusion coefficients gives rise to a complex behaviour of the SWV peak, the features of which deviate from the theory and criteria already established under the assumption of equal diffusion coefficients. Also, the theoretical treatment is notably more difficult and no analytical solution has been deduced for multipulse techniques.The effects of coupled chemical equilibria and, particularly, of unequal diffusion coefficients on SWV will be described in depth as a function of the electrode size and shape and they will be compared with those observed in differential double pulse voltammetry (DDPV). The main discrepancies in the peak height, width and position with respect to the case of equal diffusion coefficients will be studied. Also, appropriate methodologies and experimental conditions will be discussed for the determination of formal potentials and equilibrium constants.

Polarization Impact in TanDEM-X Data Over Vertical-Oriented Vegetation: The Paddy-Rice Case Study

It has been recently shown that the TanDEM-X mission is capable of tracking the plant growth of rice paddies. The precision of the elevation measure depends on the physical interaction between the synthetic aperture radar (SAR) signal and the canopy. In this letter, this interaction is studied by considering the signal polarization. In particular, the vertical and horizontal wave polarizations are compared, and their performance in the temporal mapping of the crop height is analyzed. The temporal elevation difference analysis shows a monotonically increasing trend within the reproductive stage of the canopy, with maximum height discrepancies between polarizations of about 9 cm. From an operational point of view of InSAR-based vegetation height measurements, this letter demonstrates that the oriented structure of the canopy shall be considered not only in polarimetric InSAR studies but also in the interpretation of bistatic spaceborne interferometric elevation models.

Invited Commentary

Invited Commentary

3D BUILDING RECONSTRUCTION FROM LIDAR POINT CLOUDS BY ADAPTIVE DUAL CONTOURING

Abstract. This paper presents a novel workflow for data-driven building reconstruction from Light Detection and Ranging (LiDAR) point clouds. The method comprises building extraction, a detailed roof segmentation using region growing with adaptive thresholds, segment boundary creation, and a structural 3D building reconstruction approach using adaptive 2.5D Dual Contouring. First, a 2D-grid is overlain on the segmented point cloud. Second, in each grid cell 3D vertices of the building model are estimated from the corresponding LiDAR points. Then, the number of 3D vertices is reduced in a quad-tree collapsing procedure, and the remaining vertices are connected according to their adjacency in the grid. Roof segments are represented by a Triangular Irregular Network (TIN) and are connected to each other by common vertices or - at height discrepancies - by vertical walls. Resulting 3D building models show a very high accuracy and level of detail, including roof superstructures such as dormers. The workflow is tested and evaluated for two data sets, using the evaluation method and test data of the “ISPRS Test Project on Urban Classification and 3D Building Reconstruction” (Rottensteiner et al., 2012). Results show that the proposed method is comparable with the state of the art approaches, and outperforms them regarding undersegmentation and completeness of the scene reconstruction.

Curvilinear transformation of z-shaped upper lip scar by diamond-shaped excision in secondary cleft lip deformities: a photogrammetric evaluation.

Purpose : The visible Z-shaped upper lip scar that occurs after the Tennison and Randall triangular flap technique remains a cleft stigma. Herein, we present our curvilinear transformation technique for the Z-shaped upper lip scar by diamond-shaped excision and evaluate the results using photogrammetric analyses. Patients and Methods : From 1997 to 2006, 23 patients with secondary cleft lip deformity with the visible Z-shaped upper lip scar underwent correction with the technique. The scar was excised in the diamond shape above the muscle. After curvilinear closure, the elongated length of the upper lip was excised just below the nostril sill, as the measured Cupid's bow height discrepancy. The result was assessed by the authors' standardized photogrammetry technique. Results : There was a statistically significant decrease between the preoperative central limb of the Z-shaped scar and the width of the postoperative curvilinear upper lip scar. The pre- and postoperative Cupid's bow height differences were not statistically significant. Conclusions : The curvilinear transformation of the Z-shaped scar is an efficient procedure that provides (1) a significant decrease in the width of an upper lip scar to make it less conspicuous, (2) incorporation of the scar into the philtral column, (3) a biconcave natural philtral column shape in frontal view, and (4) formation of the natural concave philtral contour in profile view.

A comparative assessment of Kalpana-1 and MISR cloud tracked winds over the Indian Ocean region

In this study, an attempt has been made to advance the error characteristic of atmospheric motion vectors (AMVs) derived from the infrared and water vapour channels of Kalpana-1 very high resolution radiometer by comparing against stereo motion vectors (SMVs) retrieved by tracking clouds from the multi-angle imaging spectro-radiometer (MISR) for a period of 9 months. Two different versions of the MISR SMVs with horizontal resolutions 70.4 and 17.6 km, respectively, are used for the inter-comparison. It is found that the Kalpana-1 AMV has stronger westerlies and southerlies than the MISR SMV at all latitudes and levels in majority of times. The performances of Kalpana-1 AMVs against MISR SMVs are assessed by doing a similar analysis where Meteosat-7 AMVs (infrared and water vapour AMVs) are also evaluated against the MISR SMVs for the same region. It is found that results of both AMVs (Kalpana-1 and Meteosat-7) with both sets of MISR SMVs are comparable with few exceptions. The zonal wind components of the MISR SMVs showed smaller mean wind difference and root mean square difference (RMSD) compared to the meridional wind components. The SMVs are typically assigned to higher altitudes than AMVs. Analysis related to the height discrepancies between MISR SMVs and AMVs shows that in the multi-layer cloud AMVs are tracked in upper level cloud targets, while SMVs are skewed more towards lower level. The accuracy is better for the low level where collocations are highly dense and gradually decreases towards the higher levels. Because of improvement in the MISR SMV retrieval algorithm, the errors in the meridional component of SMVs have improved in the recently released version with horizontal resolution of 17.6 km.

Height of South Asian children in the Netherlands aged 0–20 years: secular trends and comparisons with current Asian Indian, Dutch and WHO references

Background: People from Asian populations are generally shorter than other ethnic groups. It is unknown if current universal height references are suitable for affluent South Asian children in the Netherlands.Aims: To develop height-for-age charts for contemporary South Asian children aged 0–20 years living in the Netherlands, to evaluate secular trends, and to compare the charts with current Asian Indian, Dutch and WHO references.Subjects and methods: A population-based study measured 3315 South Asian children aged 0–20 years between 2007–2010. Among this cohort, 6876 measurements were taken. Another 7388 measurements were taken of a historical cohort of 1078 children born between 1974–1976 (aged 0–18 years).Results: An upward trend in height was observed for South Asian children living in the Netherlands between 1992–2010. The height-for-age charts of the South Asian historical cohort were similar to current Asian Indian charts. South Asian children in the Netherlands were shorter than their Dutch contemporaries at every age; and these differences increased further during adolescence. Compared to the WHO height-for-age references, there were considerable discrepancies in height, with curves intersecting twice.Conclusion: The discrepancies between the South Asian and Dutch and WHO height-for-age references indicate differences in growth patterns between the source populations.

Unusual cause of iatrogenic anterior open bite after bilateral sagittal split mandibular advancement osteotomy

We describe a case of anterior open bite after bilateral sagittal split mandibular advancement osteotomy. The discrepancy in height between the proximal and distal segments at the osteotomy sites damaged the soft tissue and caused bony interferences. Removal of the maxillary third molars and bilateral removal of bony interferences of the distal segments using a bur led to full resolution and a good orthognathic outcome on follow-up.

An Investigation of Relationships between Horse and Rider Pelvic Asymmetry

IntroductionAsymmetry of the horse and rider partnership is a challenging and complex area. There is limited scientific research regarding the occurrence of misalignments in the horse and rider, and if there is any relationship between the two. This study investigated asymmetry of single horse and rider combinations focusing on pelvis asymmetry.Methods14 single horse/rider combinations (minimum 6 month partnership) on the same daily routine were assessed. Horses and riders were assessed for misalignments of the pelvis, spine, and neck by a fully qualified human and animal (McTimoney) practitioner on the same day. Triplicate measurements of rider dorsal iliac crest (IC) distance (nearest 0.2 cm) and degree of tilt (0d.p) were recorded, sitting and standing, using a PALM palpation meter to calculate IC height discrepancy. Triplicate horse tuber coxae (TC) heights (nearest 0.5 cm) were measured using a plumb line. Difference between means indicated direction and value of asymmetry relative to symmetry of zero. Student's t‐test and Pearson's Product Moment correlation examined asymmetry relationships.ResultsMean rider IC height discrepancy, standing, was 0.89 ± 0.64 cm and sitting, 1.00 ± 0.66 cm. Mean TC height discrepancy was 1.3 ± 1.6 cm. Asymmetry of the pelvis was a feature of 93% of horse/rider combinations, 85% occurring in the same direction. There was a significant positive correlation between horse TC and rider IC height discrepancies (r2 = 0.4, F = 8.24, P = 0.014).ConclusionsThis study provides positive evidence of a relationship between the direction of horse pelvic rotation and rider pelvic tilt and also between the degree of tilt and rotation. This has implications for physical therapy treatment of horse and rider. Further research of causal effect relationships of the asymmetries is recommended.Ethical Animal ResearchProcedures were reviewed by the McTimoney Chiropractic College Ethical Review Committee. Sources of funding: none. Competing interests: none.

Morphometric analysis of the effect of scapula stabilization on obstetric brachial plexus paralysis patients.

Scapular position and size deficiency is evident in obstetric brachial plexus paralysis (OBPP) patients due to the absence of balanced muscular forces acting on the scapula. Scapula stabilization (SS) procedures aim to restore a balanced musculature and anatomic position and to augment shoulder function and enhance developmental potential. Retrospective chart review of 106 patients with OBPP between March 1979 and March 2007 was performed. Forty-one female and 27 male were included in the study. In 38 patients, the paralysis was global, 13 had Erb's paralysis with C7 root involvement; in 18 patients, the lesion was limited to C5 and C6. X-rays were evaluated, and scapula dimensions were manually measured at several stages. Shoulder abduction (SA) and external rotation (SER) outcomes were also recorded. Mean improvement was 85.68° in shoulder abduction and 36.74° in shoulder external rotation. SA and SER improvement was significantly better in those who underwent SS procedures compared to those who did not (mean improvement was increased by 9.15° and 8.54°, respectively). Improvement was noted in all scapular dimensions, in all groups, postoperatively. However, the mean improvement in scapular height, big width, small width, and oblique axis discrepancies was 4.92, 14.04, 12.66, and 13.89%, respectively, higher in patients who underwent SS procedures compared to those who did not. Dimensional discrepancies and functional outcomes are improved by SS procedures. Maximal results are attained in patients who have undergone both primary and secondary shoulder reconstruction before age 2.

High Schottky barrier height of Au contact on Si-nanowire arrays with sulfide treatment

We report on the formation of high-barrier Au contact to Si nanowires (SiNWs) with sulfide treatment. The discrepancy in Schottky barrier height (qϕB) extracted from current-voltage (I-V) and capacitance-voltage (C-V) characteristics was studied. A high qϕB of 1.03 eV is achieved between the 60 s-sulfide-treated SiNW surface and Au, which is confirmed by C-V measurements. For Au/SiNWs/n-type Si Schottky diodes, qϕB determined from C-V measurements is higher than that determined from I-V measurements, owing to the image-force lowering and the larger ideality factor than 2. However, for Au/60 s-sulfide-treated SiNWs/n-type Si Schottky diodes, the lower qϕB determined from I-V measurements than that determined from C-V measurements is attributed to a combined effect of the image-force lowering and the interfacial dipole. Note, a suitable sulfide treatment time is an important issue for producing high-quality Schottky diodes.

Double barrel fibula flap with dental rehabilitation for mandibular reconstruction

Purpose: The vascularized free fibula flap (VFFF) has become the popular reconstruction method after mandibular resection due to advantages of enough bone graft length and accepting dental implants. However, using a single fibula bone may have height discrepancy between the native mandible and grafted fibula which results in subsequent difficulty in wearing conventional dentures or osseintegrated implants. Several options could be used to resolve this problem such as delayed onlay bone graft, iliac bone reconstruction, fibula distraction and double barrel fibula flap graft. This article describes our experience in reconstruction of segmental mandible defect with double barrel fibula flap and denture rehabilitation.

Comparing three different methods of resolving height discrepancy after reconstruct mandible with fibula flap

Comparing three different methods of resolving height discrepancy after reconstruct mandible with fibula flap