Parallax Technique Research Articles

Association Between Palatally Impacted Maxillary Canine and Anomalous Maxillary Lateral Incisor - A Case Control Study

OBJECTIVE: To determine the association between palatally impacted maxillary canine (PIC) and anomalous upper lateral incisor. METHODOLOGY: This case control study was conducted on records of 60 participants (30 with PIC and 30 without). The inclusion criteria were participants without syndromes, palatal canine impaction (cases only), and age range from 12 to 30 year. Subjects with buccally impacted canine, history of previous orthodontic treatment and non-Pakistani nationals were excluded. Cases were those having PIC and controls were without PIC. Participant's OPG and periapical X-rays were used to diagnose PIC by horizontal parallax technique. Dental anomalies in upper lateral incisor were diagnosed by using casts and OPGs. Logistic regression and chi-square test was applied to determine association between PIC and anomalous upper lateral incisor. RESULTS: The mean age of the participants was 18.916±4.3 years. The frequency of missing lateral incisor was higher in cases (n=3, 10%) than control (n=1, 3.3%). Similarly peg shape laterals was more in cases (n=4, 13.3%) than controls (n=2, 6.7%). However this association was not statistically significant (P=0.37). The odd of having anomalies in lateral incisor was 2.73 times higher in cases than controls but the results were not statistically significant (P=0.177). CONCLUSION: Though the frequency of anomalous maxillary lateral incisors is higher in participants with PIC than controls but this association was not statistically significant. KEYWORDS: Palatal canine impaction, missing upper lateral incisors, peg shape upper lateral incisors, dental anomalies

Parallax techniques in presentations ceremonial theatre Ibn al-Rumi in the shanty towns (a model)

خضع المنظر المسرحي لتطورات تقنية عديدة على اختلاف العصور وتباينت في كل مرحلة زمنية إذ إن تصميم النظر وتركيبته تنطلق من شكل الفضاء سواء أكان مفتوحاً أو مغلقاً بنظرة سريعة إلى مختلف العصور التاريخية نجد الظاهرة الاحتفالية الدينية بكل أنواعها وتعدداتها، فالممارسات الاحتفالية لدى البابليين ما هي إلا الجذور الأولى للظاهرة المسرحية كذلك نجد في الاحتفالات الدينية لدى سكان وادي النيل تشابها طقوسيا ولكن نتيجة عدم وجود ادلة قطعية على تواجد هذه المظاهر بوصفها جنسا مسرحيا اصبح من غير الممكن تحديد خصوصية جمالية لرسم المعالم المسرحية لهاتين الحضارتين لذلك تظل تلك الممارسات المسرحية عملية طقوسية في مجملها وظلت تراوح في نهجها الديني

Parallax techniques in the ancient Greek theater

لا يكتمل العرض المسرحي ، إجمالا"، إلا بلمسة المنظر المتوافقة مع روح العمل لكونه العنصر الجمالي المشارك في توصيل معنى العرض إلى المتفرج ، وإذا عرفنا إن المنظر هو أكثر الفنون تأثراً بالتقدم التكنولوجي ،سندرك عندئذ الفرق بين الجانب البصري والسمعي والتشكيلي في العرض المسرحي فيما إذا كان العرض في (مسرح العلبة ،المسرح المفتوح) ومدى تأثيره في المتلقي. وبمرور التقادم التقني في استخدام مكان العرض وتحولاته من فضاءات مفتوحة إلى فضاءات مغلقة في ما يسمى بمسرح العلبة والتغايرات التي طرأت في أعادة إنتاج الفضاءات المفتوحة عبر سلسلة من التطورات والتجريب في مجالات المسرح سنلاحظ أن تلك التحولات تشكل أسئلة واستقصاءات تكشف التغايرات الحاصلة من جهة وترصد التقانه المنظرية في العصر الإغريقي من جهة ثانية لتنعكس معرفيا في فضاءات العروض المفتوحة وما يتراتب من ذلك من اعتبارات دلالية تؤثر سلبا أو إيجابا في المشاهد والمشاهد المسرحية.

Adjunctive use of fluoroscopy during MitraClip implantation reduces procedural complexity: The parallax technique.

During MitraClip implantation sub-valvular correction of trajectory and/or alignment may increase adverse clip or leaflet events. With systematic adjunctive use of fluoroscopy ("Parallax technique"), we aimed to assess parameters that minimize the need for corrective measures and help increase procedural efficiency. We retrospectively analyzed 30 patients without (Fl-) and 39 patients utilizing adjunctive fluoroscopy (Fl+) during MitraClip implantation. After establishing trajectory and supra-valvular alignment, the Parallax technique was utilized. Trajectory and alignment are maintained during advancement. All patients had 3 or 4+ MR. There were no differences in baseline demographics. The average number of clips (Fl- vs Fl+) was 1.72 ± 0.8 vs 1.59 ± 0.5, p = .57. For the first clip, the need for sub-valvular alignment (80% vs. 36%, p = .0001), eversion with retraction back to left atrium (23% vs. 10%, p = .001) and the number of grasps (2.3 ± 1.2 vs 1.4 ± 0.9) was reduced. The time from transseptal puncture to first clip deployment (71 ± 21 vs 44 ± 16 min, p = .01) was reduced. Procedural success was achieved in all but one patient in the Fl- group (p = ns). There were no differences noted for in-hospital or 30-day outcomes. Systematic use of a simple and easy to implement "Parallax technique" was associated with reduced need for sub-valvular manipulation and was associated with improved procedural times. Further larger scale studies are needed to assess the applicability of the technique.

A study of the physical properties of SB2s with both the visual and spectroscopic orbits

ABSTRACT The study of a selected set of 69 double-lined spectroscopic binaries (SB2) with well-defined visual and spectroscopic orbits was carried out. The orbital parallax, the mass, the colour, and the luminosity of each component were derived from observational data for almost all of these systems. We have also obtained an independent estimation of the component masses by comparing the colour–magnitude diagram (CMD) to the stellar evolution tracks reported by Pietrinferni. Nearly all of the observational points on the CMD are located between two tracks of slightly different mass or which fall very close to the one corresponding to a unique mass value. The masses obtained from the stellar model are in good agreement with their empirical values determined by parallax techniques (orbital, Gaia, and dynamical). This means that our adopted model is rather reliable and can therefore be used to infer further information, such as the age of each component in the studied systems. Our results indicate a fair correspondence between the age of primaries and secondary stars within 3σ. Nevertheless, we caution that these age indications suffer of uncertainties due to both inhomogeneities/low precision of the adopted photometric data and possible systematics. Finally, it is statistically shown that along with the orbital and trigonometric parallaxes, the dynamical parallax can serve as a reliable tool for distance estimates.

Measuring the Dimensions of Mechanical Component using Image Processing Techniques

This paper introduces automated process for measuring the dimensions of mechanical component. The proposed method includes image pre-processing techniques, edge detection technique, hough transform technique for circle detection and stereo vision concept is used for hole depth measurement of mechanical component. In practical, there are many factors which affects the measurement result. Noise may play key role. In order to eliminate noise effect on measurement Gaussian filtering algorithm is used. Then canny edge detection technique is used for edge detection, which helps to improve the accuracy of the result. For hole diameter measurement first we have to find out the circular shape and for circle identification we are using Hough transform technique. We are going to calculate the depth of hole by using the elevation by parallax technique. This proposed method is used for specific type of component. But in future this method can be applied for many type of real time application.

Techniques for Accurate Parallax Measurements for 6.7 GHz Methanol Masers

Abstract The BeSSeL Survey is mapping the spiral structure of the Milky Way by measuring trigonometric parallaxes of hundreds of maser sources associated with high-mass star formation. While parallax techniques for water masers at high frequency (22 GHz) have been well documented, recent observations of methanol masers at lower frequency (6.7 GHz) have revealed astrometric issues associated with signal propagation through the ionosphere that could significantly limit parallax accuracy. These problems displayed as a “parallax gradient” on the sky when measured against different background quasars. We present an analysis method in which we generate position data relative to an “artificial quasar” at the target maser position at each epoch. Fitting parallax to these data can significantly mitigate the problems and improve parallax accuracy.

MP23-19 THE SIMPORTAL FLUORO-LESS C-ARM TRAINER (CAT): PRELIMINARY TRAINING RESULTS

You have accessJournal of UrologyTechnology & Instruments: Surgical Education & Skills Assessment II1 Apr 2015MP23-19 THE SIMPORTAL FLUORO-LESS C-ARM TRAINER (CAT): PRELIMINARY TRAINING RESULTS Domenico Veneziano, Arthur Smith, David Hananel, Troy Reihsen, Jack Stubbs, Jason Speich, and Robert Sweet Domenico VenezianoDomenico Veneziano More articles by this author , Arthur SmithArthur Smith More articles by this author , David HananelDavid Hananel More articles by this author , Troy ReihsenTroy Reihsen More articles by this author , Jack StubbsJack Stubbs More articles by this author , Jason SpeichJason Speich More articles by this author , and Robert SweetRobert Sweet More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1262AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Achieving proper renal access is arguably the most challenging component of percutaneous nephrolithotomy (PCNL). The use of a C-arm is a core skill required during this procedure is fluoroscopic imaging and parallax techniques for proper needle insertion into a predetermined calyceal papilla. The trainers available for these skills include VR simulators and physical models requiring actual fluoroscopy and radiation exposure precautions. In this study we present the successful proof-of-concept of a low-cost physical fluoro-less C-arm trainer (CAT) for training percutaneous renal access. METHODS The SimPORTAL CAT includes a mini C-arm for simulating fluoroscopic imaging and a silicon flank simulation model for needle insertion. The C-arm has two mounted video cameras and is jointed to tilt and rainbow. The flank model contains an anatomically accurate cast of the upper urinary tract including the ureter, calyces, and the renal pelvis with an overlay of ribs to visually and tactically simulate the 10th-12th ribs. The simulated fluoroscopic imaging is viewed on a computer screen allowing for real time visualization. Preliminary surveys were completed by participants (n=14) at a training course that took place in Hemel Hampsted (UK) to obtain information on the acceptability of version 2.1 of the model. RESULTS We have successfully created a fluoro-less C-arm trainer (CAT) that achieves the goals of training percutaneous access of the kidney. All participants (100%) considered the concept of avoiding radiation exposure during training as a highly valuable feature. 92,8% of the enrolled participants considered the CAT of at least equal value to existing VR training models. CONCLUSIONS The fluoroscopy-less CAT is an economically feasible and accurate model for training parallax. It effectively replicates the functions of a C-arm X-ray system for percutaneous access to the kidney without any radiation exposure to the learner. Further studies will examine construct validity for training and assessing percutaneous access skills. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e274 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Domenico Veneziano More articles by this author Arthur Smith More articles by this author David Hananel More articles by this author Troy Reihsen More articles by this author Jack Stubbs More articles by this author Jason Speich More articles by this author Robert Sweet More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The SimPORTAL fluoro-less C-arm trainer: an innovative device for percutaneous kidney access.

Achieving proper renal access is arguably the most challenging component of percutaneous nephrolithotomy. A core skill required during this procedure is the use of C-arm fluoroscopic imaging and parallax techniques for proper needle insertion into a predetermined calyceal papilla. The trainers available for these skills include virtual reality (VR) simulators and physical models requiring actual fluoroscopy and radiation exposure precautions. In this study we present the successful proof-of-concept of a low-cost physical fluoro-less C-arm trainer (CAT) for training percutaneous renal access. The SimPORTAL CAT includes a mini C-arm for simulating fluoroscopic imaging and a silicon flank simulation model for needle insertion. The C-arm has two mounted video cameras and is jointed to tilt and rainbow. The flank model contains an anatomically accurate cast of the upper urinary tract, including the ureter, calyces, and the renal pelvis, with an overlay of ribs to visually and tactically simulate the 10th-12th ribs. The simulated fluoroscopic imaging is viewed on a computer screen allowing for real-time visualization. Preliminary surveys were completed by participants (n=14) at a training course that took place in Hemel Hampsted to obtain information on the acceptability of version 2.1 of the model. We have successfully created a fluoro-less CAT that achieves the goals of training percutaneous access of the kidney. All participants (100%) considered the concept of avoiding radiation exposure during training as a highly valuable feature. About 92.8% of the enrolled participants considered the CAT of at least equal value to existing VR training models. The fluoroscopy-less CAT is an economically feasible and accurate model for training parallax. It effectively replicates the functions of a C-arm X-ray system for percutaneous access to the kidney without any radiation exposure to the learner. Further studies will examine construct validity for training and assessing percutaneous access skills.

Measurement and experience of the presence by representative technique of visual intepretation in the stereopsis - In terms of stable, gradual and irregular interpretation

In 3D stereopsis, perspective method of 2D video, parallax between inside the screen and out, and a positive parallax technique were used to create a sense of space. However, the representation of three dimensional effect by the parallax technique may cause fatigue, reducing the pleasure of watching a movie for a long time. This research focuses on a video representative technique to immerse naturally into the space by a stereopsis that is not focused on the projection of the object only. In order to conduct the research, we edited a movie to identify three groups’ (Stable, gradual and irregular interpretation) visual representation, and analyzed the presence effect when the viewer experienced the presence. The result shows that the gradual interpretation technique showed a high value of pleasure, arousal and presence since the viewer felt comfort and reality by immersion of the space. On the other hand, the irregular interpretation decreased the viewer’s visual properties, while the value of presence, pleasure and arousal was low.

The Derby parallax technique for marking levels in thoracic spinal surgery.

The Derby parallax technique for marking levels in thoracic spinal surgery.

Localization of ectopic maxillary canines — is CBCT more accurate than conventional horizontal or vertical parallax?

To compare the accuracy of cone-beam CT (CBCT) with conventional horizontal and vertical parallax for the localization of ectopic maxillary canines. Observational study. A typodont was constructed using human teeth embedded in radio-dense impression material, containing a simulated ectopic canine. Image sets (vertical/horizontal parallax and CBCT scans) were obtained for nine positions. A photograph confirmed the true position of the canine. Six observers used horizontal (HP) and vertical (VP) parallax techniques with conventional radiographs and the axial, coronal and sagittal CBCT views to locate the canine tip. Images were manipulated as required using proprietary software (http://www.carestream.com and http://www.i-cat.com). Intra-observer reproducibility was calculated by one observer re-evaluating the image sets after 2 months. Individual observer validity was calculated in relation to the photographic position of the canine using weighted Kappa. Differences in the proportion of correct locations between CBCT and vertical/horizontal parallax were tested using McNemar tests (P<0·05). Intra- and inter-observer agreements were excellent (0·8985) and substantial (0·7528), respectively. Individual observer validity was substantial-excellent (0·7368-0·900). The canine position was correctly identified in 94% of cases located using CBCT, 83% using HP and 65% using VP. The differences between CBCT and vertical and horizontal parallax were highly statistically significant (P<0·01). CBCT is more accurate than either horizontal or vertical parallax for the localization of ectopic maxillary canine teeth.

Diagnosis and localization of impacted maxillary canines: comparison of methods

Numerous clinical signs may be indicative of a canine impaction; however, studies determining the efficiency of visual inspection and digital palpation in localizing an impacted maxillary canine are sparse. Of the radiographic techniques, no studies have compared the accuracy of the horizontal and the vertical parallax techniques to determine the location of an impacted canine. Hence, the objectives of this study were to evaluate the efficiency of visual inspection and digital palpation, and to compare the accuracy of the horizontal and vertical parallax techniques in determining the location of an impacted maxillary canine. The study sample comprised the records of 522 patients who had attended a dental hospital. The location of an impacted maxillary canine was determined radiographically using the vertical and the horizontal parallax principles. The findings were then confirmed from the surgical records in those cases that had undergone surgical intervention of the impacted canine. The position of the impacted canine was determined successfully by visual inspection and digital palpation in 85.3 and 85.2% of the cases respectively. The vertical parallax technique demonstrated a higher degree of accuracy (97.7%) and a greater degree of diagnostic capability (98.2%) when compared with the horizontal parallax technique (92.6 and 78.0% respectively).

Cross-lenticular lens array for full parallax 3-D display with crosstalk reduction

As a 3-D display technology, stereoscopic imaging with lenticular lens sheet can only offer viewers the horizontal parallax. To reconstruct the 3-D image with parallax in both horizontal and vertical directions, the full parallax technique with micro-lens array was proposed. But due to the fabrication constraints and cost concerns of the micro-lens array, application of the full parallax technique is restricted in practice. In this paper we revisited the lenticular sheet method and cross-lenticular lens array formed by two lenticular sheets overlapped orthogonally. By analyzing the optical properties of this cross-lenticular lens array, we found that it has reasonable imaging qualities as a conventional micro-lens array. Besides, due to the poor optical property of the outskirt area of the cross-lenticular lens, the cross-lenticular lens array has better crosstalk suppression capability than the conventional one. Based on the analysis, in this paper, we used the proposed lens array to reconstruct a 3-D image and verified its practicability. The cross-lenticular lens array was found feasible to take the full parallax technique into commercial applications, with comparable advantages in terms of low-cost and easy fabrication over a large area.

Staple diet: a foreign body in a tooth

The chance discovery of a foreign object embedded in a tooth is uncommon, and requires radiographic examination to determine the composition and location of the object. The authors describe the case of an 11-year-old boy who presented with a staple lodged in the root canal of the maxillary left permanent central incisor. This staple was localized using parallax techniques and successfully removed from the canal. The radiographic techniques of localization and possible methods of removal of foreign bodies are discussed.

Determination of the altitudinal peak of Cosmic Noise Absorption using a vertical parallax technique

The riometry technique is limited by its inability to directly determine the altitude of the principal ionospheric absorption layer during periods of enhanced Cosmic Noise Absorption (CNA). We describe here a technique based on the simple vertical parallax principle, enabling direct measurements of this altitude. The technique utilizes the overlapping beams of two closely spaced imaging riometers in Antarctica. Descriptive statistics on peak absorption heights are presented. The altitude determination of a D‐region absorption event and an event that occurred in the F‐region near 200 km altitude are presented in more detail. The identification of an F‐region event using the parallax technique confirms earlier findings that radiowave absorption in the F‐region is a potentially significant contributor to CNA. This technique enables a simple and repeatable ground‐based measurement of the altitude of the CNA layer peak, and can be extended to estimating precipitation spectra based on peak absorption heights.

The kinematics and zero point of the log P –〈MK〉 relation for galactic field RR Lyrae variables via statistical parallax

AbstractThe kinematical parameters of the local field RR Lyrae population and the zero point of the log P –〈MK〉 relation for these variables are inferred by applying the statistical parallax (maximum-likelihood) technique to a sample of 379 RR Lyrae stars with known periods, radial-velocities, metallicities, K-band photometry, and absolute proper motions on the ICRS system. Hipparcos, Tycho-2, SPM, UCAC1 and NPM1 were used as the sources of proper motions. The K-band magnitudes were adopted from the 2MASS All-Sky Data Release. The parameters of the velocity distribution are found to be (U0 = −13 ± 9, V0 = −41 ± 7, W0 = −19±4) kms−1, (σU = 66±9, σV = 47±7, σW = 23±5) km s−1 and (U0 = −11±10, V0 = −224±8, W0 = −8±6) km s−1 (σU = 158±9, σV = 95±5, σW = 88±5) km s−1 for the thick-disk (the purest disk sample, 56 stars) and halo (the purest halo sample, 264 stars) objects, respectively. The zero point of the infrared PL relation of Jones et al. (1992 – based on the results obtained using the Baade-Wesselink method) is confirmed: we find 〈MK〉 = −2.33⋅log PF−0.89±0.09, which is only brighter than found using the Baade-Wesselink method (Jones et al. 1992). A conversion of the resulting log P –〈MK〉 relation to V-band luminosities yields the metallicity-luminosity relation 〈MV〉 = +1.12 + 0.18 ⋅ [Fe/H] ± 0.10. Our results imply a solar Galactocentric distance of R0 = 7.8±0.4 kpc and an LMC distance modulus of DMLMC = 18.17 ±0.10 (cluster RR Lyraes) or DMLMC = 18.10±0.10 (field RR Lyraes), thereby favoring the so-called short distance scale.

The log P - $\langle M_{K}\rangle$ Relation of Galactic Field RR Lyrae Variables

The kinematical parameters of the local field RR Lyrae population and the zero-point of the log relation for these variables are inferred by applying the statistical parallax (maximum-likeli-hood) technique to a sample of 182 RR Lyraes with known periods, radial-velocities, metallicities, K-band photometry, and absolute proper motions on the ICRS system. Hipparcos, Tycho-2, SPM, UCAC, NPM1, and the Four-Million Star Catalog (Volchkov et al. 1992) were used as the sources of proper motions; the proper motions of the last two catalogs are reduced to the Hipparcos (ICRS) system (Dambis & Rastorguev 2001). The K-band magnitudes were adopted from the list of Fernley et al. (1998) and supplemented by the data of the 2MASS Second Incremental Data Release. The parameters of the velocity distribution are found to be: (, , km s-1; (, , ) km s-1: and (, , ) km s-1; (, , ) km s-1 for the thick-disk (41 stars) and halo (141 stars) objects, respectively. The zero-point of the infrared PL relation of Jones et al. (1992) (based on the results obtained using the Baade-Wesselink method) is confirmed: we find compared to as inferred by Jones et al. (1992). A conversion of the resulting log relation to V-band luminosities yields the metallicity-luminosity relation Fe/H. Our results imply a solar Galactocentric distance of kpc and an LMC distance modulus of (cluster RR Lyraes) or (field RR Lyraes), thereby favoring the so-called short distance scale.

Construction Of Standardised Simulated Root Canals In Resin Blocks For Pre-clinical Teaching

To determine the amount of displacement of a structure noticed on an image when the tube of a dental X-ray machine was shifted vertically and horizontally. In addition, various intraoral images were combined with dental panoramic images to determine the location of structures. Our research is based on the parallax technique which requires manipulation of horizontal and vertical angulations of the X-ray tube. A metal object is positioned on the buccal and palatal side of the maxilla on the canine area of a skull. The X-ray tube is shifted incrementally to obtain images on phosphor plates. Subsequently, panaromic and occlusal images were taken to assist in localization of the metal object. To obtain a clear image shift of 2-3mm using the parallax method, there must be an adequate horizontal tube shift of approximately 30-35 degrees. When images were used in combination of dental panoramic images, it was found that the buccally placed structures can be accurately located with the periapical or occlusal images. However, the displacement of images in the palatally placed structures in panoramic imaging is not fully appreciated with the principle of parallax method. Tube movement of 30-35 degrees horizontally is needed for a 2-3 mm image shift. To successfully localize a buccal structure, a combination of either periapical or occlusal images with a dental panoramic imaging can be employed. However, this combination with panoramic imaging is limited when looking at palatally placed structures.

ITAL]Hubble Space Telescope[/ITAL] Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448

We have combined two epochs of Hubble Space Telescope WFPC2 imaging data with ground-based expansion velocities to determine distances to three planetary nebulae (NGC 6578, NGC 6884, and IC 2448). We used two variants of the expansion parallax technique—a gradient method and a magnification method—to determine the distances. The results from the two methods agree to within the errors. A fourth nebula was included in the study (NGC 6891), but the expansion was too small to determine the distance, and only a lower limit was obtained. This is the second paper in a series that will examine at least 24 nebulae in total.