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Sample records for axial sagittal coronal

  1. Evaluation of reformatted sagittal CT images for measurement of condylar position. Comparison between original axial and coronal images

    Energy Technology Data Exchange (ETDEWEB)

    Hiruma, Takayoshi; Funato, Masahiko; Suganuma, Takeshi; Shinya, Akiyuki; Furuya, Ryoichi; Kawawa, Tadaharu; Seki, Kenji; Okano, Tomohiro [Showa Univ., Tokyo (Japan). School of Dentistry

    1995-09-01

    Accurate measurement of the condylar position is important for diagnosis and treatment of temporomandibular joint dysfunction. Conventional radiographic techniques have been used for this purpose and the recent advance of computed tomography (CT) is applicable to temporomandibular joints. The accuracy of CT in the measurement of the condylar position is still unclear. The purpose of this study was to evaluate the measurement accuracy of the condylar position on reformatted sagittal CT images. Six TMJs obtained from dried skulls were used. The TMJs were examined using a CT scanner with 1 mm thickness/interval in the axial and coronal directions. The visibility of the condyle and fossa on the reformatted sagittal images created were evaluated by measuring the joint space defined in our study. The results were as follows: (1) The superior surface of the condyle and the deepest part of the fossa were obscured in the reformatted images created from the axial scan and coronal scan projected at 60deg to the F-H plane. (2) The reformatted images from the coronal scan projected at 90deg, 80deg or 70deg to the F-H plane clearly depicted the condyle and fossa, the reproducibility of the measurement on these images mentioned above was less than 0.1 mm. The results indicated that the coronal scan from 90deg to 70deg to the F-H plane is more accurate than the axial scan for determining the condylar position on the reformatted sagittal images. (author).

  2. 5D CNS+ Software for Automatically Imaging Axial, Sagittal, and Coronal Planes of Normal and Abnormal Second-Trimester Fetal Brains.

    Science.gov (United States)

    Rizzo, Giuseppe; Capponi, Alessandra; Persico, Nicola; Ghi, Tullio; Nazzaro, Giovanni; Boito, Simona; Pietrolucci, Maria Elena; Arduini, Domenico

    2016-10-01

    The purpose of this study was to test new 5D CNS+ software (Samsung Medison Co, Ltd, Seoul, Korea), which is designed to image axial, sagittal, and coronal planes of the fetal brain from volumes obtained by 3-dimensional sonography. The study consisted of 2 different steps. First in a prospective study, 3-dimensional fetal brain volumes were acquired in 183 normal consecutive singleton pregnancies undergoing routine sonographic examinations at 18 to 24 weeks' gestation. The 5D CNS+ software was applied, and the percentage of adequate visualization of brain diagnostic planes was evaluated by 2 independent observers. In the second step, the software was also tested in 22 fetuses with cerebral anomalies. In 180 of 183 fetuses (98.4%), 5D CNS+ successfully reconstructed all of the diagnostic planes. Using the software on healthy fetuses, the observers acknowledged the presence of diagnostic images with visualization rates ranging from 97.7% to 99.4% for axial planes, 94.4% to 97.7% for sagittal planes, and 92.2% to 97.2% for coronal planes. The Cohen κ coefficient was analyzed to evaluate the agreement rates between the observers and resulted in values of 0.96 or greater for axial planes, 0.90 or greater for sagittal planes, and 0.89 or greater for coronal planes. All 22 fetuses with brain anomalies were identified among a series that also included healthy fetuses, and in 21 of the 22 cases, a correct diagnosis was made. 5D CNS+ was efficient in successfully imaging standard axial, sagittal, and coronal planes of the fetal brain. This approach may simplify the examination of the fetal central nervous system and reduce operator dependency.

  3. Effect of alignment changes on sagittal and coronal socket reaction moment interactions in transtibial prostheses.

    Science.gov (United States)

    Kobayashi, Toshiki; Orendurff, Michael S; Zhang, Ming; Boone, David A

    2013-04-26

    Alignment is important for comfortable and stable gait of lower-limb prosthesis users. The magnitude of socket reaction moments in the multiple planes acting simultaneously upon the residual limb may be related to perception of comfort in individuals using prostheses through socket interface pressures. The aim of this study was to investigate the effect of prosthetic alignment changes on sagittal and coronal socket reaction moment interactions (moment-moment curves) and to characterize the curves in 11 individuals with transtibial amputation using novel moment-moment interaction parameters measured by plotting sagittal socket reaction moments versus coronal ones under various alignment conditions. A custom instrumented prosthesis alignment component was used to measure socket reaction moments during walking. Prosthetic alignment was tuned to a nominally aligned condition by a prosthetist, and from this position, angular (3° and 6° of flexion, extension, abduction or adduction of the socket) and translational (5mm and 10mm of anterior, posterior, medial or lateral translation of the socket) alignment changes were performed in either the sagittal or the coronal plane in a randomized manner. A total of 17 alignment conditions were tested. Coronal angulation and translation alignment changes demonstrated similar consistent changes in the moment-moment curves. Sagittal alignment changes demonstrated more complex changes compared to the coronal alignment changes. Effect of sagittal angulations and translations on the moment-moment curves was different during 2nd rocker (mid-stance) with extension malalignment appearing to cause medio-lateral instability. Presentation of coronal and sagittal socket reaction moment interactions may provide useful visual information for prosthetists to understand the biomechanical effects of malalignment of transtibial prostheses.

  4. Brief communication: age and fractal dimensions of human sagittal and coronal sutures

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Jacobsen, Jens Christian Brings

    2003-01-01

    The fractal dimensions of human sagittal and coronal sutures were calculated on 31 complete skulls from the Terry Collection. The aim was to investigate whether the fractal dimension, relying on the whole sutural length, might yield a better description of age-related changes in sutural morphology......, as opposed to other methods of quantification, which generally rely on more arbitrary scoring systems. However, the fractal dimension did not yield better age correlations than other previously described methods. At best, the results reflected the general observation that young adults below age 40 years...

  5. Computed tomography of the sella turcica content in coronal and axial plane

    Energy Technology Data Exchange (ETDEWEB)

    Lovrencic, M.; Kalousek, M.; Klaric, R.; Sekso, M.

    1984-10-01

    Computed tomography of the pituitary fossa in the axial and coronal plane have been performed in 40 patients. The use of both planes has improved diagnostic accuracy through a more exact spatial demonstration. The method has also been reliable in the detection of pituitary microadenomas. The use of both planes has a limited diagnostic accuracy due artefacts in coronal plane.

  6. Lower lumbar spine axial rotation is reduced in end-range sagittal postures when compared to a neutral spine posture.

    Science.gov (United States)

    Burnett, Angus; O'Sullivan, Peter; Ankarberg, Lars; Gooding, Megan; Nelis, Rogier; Offermann, Frank; Persson, Jannike

    2008-08-01

    Sports such as rowing, gymnastics, cycling and fast bowling in cricket that combine rotation with spine flexion and extension are known to carry greater risk of low back pain (LBP). Few studies have investigated the capacity of the lumbar spine to rotate in various sagittal positions, and further, these studies have generated disparate conclusions. The purpose of this study was to determine whether the range of lower lumbar axial rotation (L3-S2) is decreased in end-range flexion and extension postures when compared to the neutral spine posture. Eighteen adolescent female rowers (mean age=14.9 years) with no history of LBP were recruited for this study. Lower lumbar axial rotation was measured by an electromagnetic tracking system (3-Space Fastrak) in end-range flexion, extension and neutral postures, in sitting and standing positions. There was a reduction in the range of lower lumbar axial rotation in both end-range extension and flexion (ppostures when compared to neutral. Further, the range of lower lumbar axial rotation measurements in flexion when sitting was reduced when compared to standing (p=0.013). These findings are likely due to the anatomical limitations of the passive structures in end-range sagittal postures.

  7. First Simultaneous Views of the Axial and Lateral Perspectives of a Coronal Mass Ejection

    CERN Document Server

    Cabello, I; Balmaceda, L; Dohmen, I

    2016-01-01

    The different appearances exhibited by coronal mass ejections (CMEs) are believed to be in part the result of different orientations of their main axis of symmetry, consistent with a flux-rope configuration. There are observational reports of CMEs seen along their main axis (axial perspective) and perpendicular to it (lateral perspective), but no simultaneous observations of both perspectives from the same CME have been reported to date. The stereoscopic views of the telescopes onboard the $Solar$-$Terrestrial$ $Relations$ $Observatory$ (STEREO) twin spacecraft, in combination with the views from the $Solar$ $and$ $Heliospheric$ $Observatory$ (SOHO) and the $Solar$ $Dynamics$ $Observatory$ (SDO), allow us to study the axial and lateral perspectives of a CME simultaneously for the first time. In addition, this study shows that the lateral angular extent ($L$) increases linearly with time, while the angular extent of the axial perspective ($D$) presents this behavior only from the low corona to $\\approx\\,$5 $R_...

  8. Comparative Study between Axial and Coronal Planes of CT Enterography in Evaluation of Disease Activity and Complications of Crohn Disease

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Eun; Park, Seong Jin; Moon, Soung Kyung; Lim, Joo Won; Lee, Dong Ho; Ko, Young Tae; Kim, Hyo Jong [Dept. of Kyung Hee University Hospital, Seoul (Korea, Republic of)

    2013-02-15

    To retrospectively compare the accuracy of axial and coronal planes of CT enterography for detection of pathologic findings of Crohn disease. 168 patients who were suspected of having Crohn disease underwent CT enterography. 66 patients who were diagnosed Crohn disease were retrospectively evaluated (endoscopic biopsy of terminal ileum: 12 patients, segmental resection of small bowel: 6 patients, diagnosed based on a combination of clinical, histopathological and imaging findings: 48 patients). 2 radiologists reviewed axial planes of CT enterography and one month later reviewed coronal planes. CT enterography findings of active phase, chronic phase and complications of Crohn disease were evaluated and then compared with axial and coronal planes by using chi-square test. Mucosal hyperenhancement, wall thickening, and mesenteric fat stranding were more detected on axial planes, which were CT findings of active Crohn disease. Pseudosacculation, fibrotic strictures, fistulas, abscesses were more detected on coronal planes, which were CT findings of chronic Crohn disease or complications. In particular, pseudosacculation and fibrotic strictures were significantly more detected on coronal planes. When evaluating CT enterography in Crohn disease, coronal planes provide more useful diagnostic information of pseudosacculation and fibrotic strictures.

  9. Intrinsic and Extrinsic Contributions to Seated Balance in the Sagittal and Coronal Planes: Implications for Trunk Control After Spinal Cord Injury.

    Science.gov (United States)

    Audu, Musa L; Triolo, Ronald J

    2015-08-01

    The contributions of intrinsic (passive) and extrinsic (active) properties of the human trunk, in terms of the simultaneous actions about the hip and spinal joints, to the control of sagittal and coronal seated balance were examined. Able-bodied (ABD) and spinal-cord-injured (SCI) volunteers sat on a moving platform which underwent small amplitude perturbations in the anterior-posterior (AP) and medial-lateral (ML) directions while changes to trunk orientation were measured. A linear parametric model that related platform movement to trunk angle was fit to the experimental data by identifying model parameters in the time domain. The results showed that spinal cord injury leads to a systematic reduction in the extrinsic characteristics, while most of the intrinsic characteristics were rarely affected. In both SCI and ABD individuals, passive characteristics alone were not enough to maintain seated balance. Passive stiffness in the ML direction was almost 3 times that in the AP direction, making more extrinsic mechanisms necessary for balance in the latter direction. Proportional and derivative terms of the extrinsic model made the largest contribution to the overall output from the active system, implying that a simple proportional plus derivative (PD) controller structure will suffice for restoring seated balance after spinal cord injury.

  10. Narrow CSF space at high convexity and high midline areas in idiopathic normal pressure hydrocephalus detected by axial and coronal MRI

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Makoto [Iwate Medical University, Department of Radiology, Morioka (Japan); Honda, Satoshi [St. Luke' s International Hospital, Department of Radiology, Tokyo (Japan); Yuasa, Tatsuhiko; Iwamura, Akihide [Kohnodai Hospital, National Center of Neurology and Psychiatry, Department of Neurology, Ichikawa (Japan); Shibata, Eri [Iwate Medical University, Department of Neuropsychiatry, Morioka (Japan); Ohba, Hideki [Iwate Medical University, Department of Neurology, Morioka (Japan)

    2008-02-15

    The aim of this study was to determine the performance of axial and coronal magnetic resonance imaging (MRI) in detecting the narrowing of the cerebrospinal fluid (CSF) space at the high convexity and high midline areas, which is speculated to be one of the clinical characteristics of idiopathic normal pressure hydrocephalus (iNPH). We retrospectively examined axial and coronal T1-weighted images of 14 iNPH patients and 12 age-matched controls. The narrowness of the CSF space at the high convexity/midline was blindly evaluated by five raters using a continuous confidence rating scale for receiver operating characteristic (ROC) analysis. Axial and coronal imaging accurately determined the presence of the narrow cisterns/sulci at the high convexity/midline and was capable of predicting probable/definite iNPH with a high degree of accuracy. there were also no significant differences in the detection of this finding between the axial and coronal images. Both axial and coronal T1-weighted MRI can detect the narrow CSF space at the high convexity/midline accurately and may therefore facilitate clinicians in choosing a management strategy for iNPH patients. (orig.)

  11. Coronal Diffusion-weighted Magnetic Resonance Imaging of the Kidney: Agreement with Axial Diffusion-weighted Magnetic Imaging in Terms of Apparent Diffusion Coefficient Values

    Institute of Scientific and Technical Information of China (English)

    Hai-Yi Wang; Jia Wang; Ye-Huan Tang; Hui-Yi Ye; Lin Ma

    2015-01-01

    Background:Coronal diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values have gradually become applied (following conventional axial DW-MRI) in the renal analysis.To explore whether data obtained using coronal DW-MRI are comparable with those derived using axial DW-MRI,this preliminary study sought to assess the agreement in renal ADC values between coronal DW-MRI and axial DW-MRI.Methods:Thirty-four healthy volunteers were enrolled in the study; written consents were obtained.All subjects underwent respiratory-triggered axial and coronal DW-MRI using a 1.5-MR system with b values of 0 and 800 s/mm2.The signal-to-noise ratios (SNRs) of the two DW-MRI sequences were measured and statistically compared using the paired t-test.The extent of agreement of ADC values of the upper pole,mid-pole,and lower pole of the kidney; the mean ADC values of the left kidney and right kidney; and the mean ADC values of the bilateral kidneys were evaluated via calculation of intraclass correlation coefficients (ICCs) or Bland-Altman method between the two DW-MRI sequences.Results:The SNR of coronal DW-MR images was statistically inferior to that of axial DW-MR images (P < 0.001).The ICCs of the ADC values of each region of interest,and the mean ADC values of bilateral kidneys,between the two sequences,were greater than 0.5,and the mean ADCs of the bilateral kidneys demonstrated the highest ICC (0.869; 95% confidence interval:0.739-0.935).In addition,94.1% (32/34),94.1% (32/34),and 97.1% (31/34) of the ADC bias was inside the limits of agreement in terms of the mean ADC values of the left kidneys,right kidneys,and bilateral kidneys when coronal and axial DWI-MRI were compared.Conclusions:ADC values derived using coronal DW-MRI exhibited moderate-to-good agreement to those of axial DW-MRI,rendering the former an additional useful DW-MRI method,and causing the ADC values derived using the two types of DW-MRI to be comparable.

  12. Functional CT imaging of the lung in the axial and coronal plane after single-lung transplantation; Computertomographische Funktionsuntersuchung der Lunge nach einseitiger Lungentransplantation mit axialer und koronarer Akquisition

    Energy Technology Data Exchange (ETDEWEB)

    Kauczor, H.U. [Mainz Univ. (Germany). Klinik fuer Radiologie; Buchenroth, M. [Mainz Univ. (Germany). 3. Medizinische Klinik - Pneumologie; Heussel, C.P. [Mainz Univ. (Germany). Klinik fuer Radiologie; Mayer, E. [Mainz Univ. (Germany). Klinik fuer Herz-, Thorax-, Gefaesschirurgie

    1996-05-01

    After single-lung transplantation in a patient suffering from obstructive emphysema lung function parameters worsened during follow-up. To conplement the routine high-resolution CT (HRCT) scans acquired in inspiration, additional scans were obtained to evaluate regional lung function. The comparison of HRCT scans acquired in inspiration and in expiration revealed different ventilation conditions of both lungs, continuous acquisition in a single slice (dynamic multiscan acquisition) in the axial and coronal plane demonstrated mediastinal shifting and the movement of the diaphragm during the whole breathing cycle. Both modalities can provide important information concerning regional differences of ventilation after single-lung transplantation. Expiratory HRCT should be applied on a regular basis in the follow-up of patients after single-lung transplantation. Expiratory HRCT should be applied on a regular basis in the follow-up of patients after single-lung transplantation. The application of axial and coronal dynamic multiscan acquisitions will be helpful in particular clinical conditions, like increasing hyperinflation, mediastinal shifting or bronchial collapse within the region of the anastomosis. (orig.) [Deutsch] Nach Einzellungentransplantation wegen eines obstruktiven Emphysems wurden bei einem Patienten in der Nachsorge zur Abklaerung einer Verschlechterung der Lungenfunktionsparameter neben einer hochaufloesenden CT (HRCT) in Inspiration zusaetzliche Aufnahmen zur Funktionsbeurteilung durchgefuehrt. Der Vergleich von HRCT-Aufnahmen in In- und Exspiration zeigte die unterschiedlichen Ventilationsverhaeltnisse bei beiden Lungen; kontinuierliche Aufnahmen in einer Schicht (Multirotationsaufnahmen) stellten bei axialer und insbesondere bei direkter koronarer Akquisition die Mediastinal- und Zwerchfellbewegung waehrend des gesamten Atemzyklus dar. Beide Verfahren koennen wichtige Zusatzinformationen ueber regionale Ventilationsdifferenzen nach einseitiger

  13. Reformatted images improve the detection rate of acute traumatic subdural hematomas on brain CT compared with axial images alone.

    Science.gov (United States)

    Amrhein, Timothy J; Mostertz, William; Matheus, Maria Gisele; Maass-Bolles, Genevieve; Sharma, Komal; Collins, Heather R; Kranz, Peter G

    2017-02-01

    Subdural hematomas (SDHs) comprise a significant percentage of missed intracranial hemorrhage on axial brain CT. SDH detection rates could be improved with the addition of reformatted images. Though performed at some centers, the potential additional diagnostic sensitivity of reformatted images has not yet been investigated. The purpose of our study is to determine if the addition of coronal and sagittal reformatted images to an axial brain CT increases the sensitivity and specificity for detection of acute traumatic SDH. We retrospectively reviewed consecutive brain CTs acquired for acute trauma that contained new SDHs. An equivalent number of normal brain CTs served as control. Paired sets of images were created for each case: (1) axial images only ("axial only") and (2) axial, coronal, sagittal images ("reformat added"). Three readers interpreted both the axial only and companion reformat added for each case, separated by 1 month. Reading times and SDH detection rates were compared. One hundred SDH and 100 negative examinations were collected. Sensitivity and specificity for the axial-only scans were 75.7 and 94.3 %, respectively, compared with 88.3 and 98.3 % for reformat added. There was a 24.3 % false negative (missed SDH) rate with axial-only scans versus 11.7 % with reformat added (p = negatives by greater than 50 %. Reformatted images substantially reduce the number of missed SDHs compared with axial images alone.

  14. Fixed Sagittal Plane Imbalance

    OpenAIRE

    Savage, Jason W.; Patel, Alpesh A.

    2014-01-01

    Study Design Literature review. Objective To discuss the evaluation and management of fixed sagittal plane imbalance. Methods A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is ...

  15. Lumbosacral transitional vertebra and S1 radiculopathy: the value of coronal MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bezuidenhout, Abraham Fourie; Lotz, Jan Willem [Stellenbosch University, Division of Radiodiagnosis, Department of Medical Imaging and Clinical Oncology, Faculty of Medicine and Health Sciences, Tygerberg (South Africa)

    2014-06-15

    The association of a lumbosacral transitional vertebra with accelerated degeneration of the disc above has been described. Lumbosacral transitional vertebrae have also been reported as a cause of extraforaminal entrapment of the L5 nerve root between the transverse segment of the transitional vertebra and the sacral ala optimally demonstrated by coronal MRI. The association of the lumbosacral transitional vertebra pseudoarthroses and S1 nerve root entrapment due to degenerative stenosis of the nerve root canal has never been described. We present 12 patients with lumbosacral transitional vertebrae that were referred for symptoms and signs of S1 nerve root radiculopathy in which the sagittal and axial MRI sequences failed to identify a plausible cause for the patients' S1 nerve root symptoms. A coronal T1-weighted imaging (T1WI) MRI sequence was consequently added to the investigation. The coronal T1WI MRI sequence demonstrated hypertrophic degenerative stenosis of the S1 nerve root canal at the level of the lumbosacral transitional vertebra pseudoarthrosis, with entrapment of the respective S1 nerve root in all patients. We emphasize the value of coronal T1WI MRI of the lumbosacral junction and sacrum if the cause for S1 radicular symptoms was not identified on conventional sagittal and axial MRI sequences in patients with lumbosacral transitional vertebrae. (orig.)

  16. Importance of sagittal MR imaging in nontraumatic femoral head osteonecrosis in children

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Alice S. [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Wells, Lawrence [Children' s Hospital of Philadelphia, Department of Orthopedic Surgery, Philadelphia, PA (United States); Jaramillo, Diego [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2008-11-15

    In nontraumatic femoral head osteonecrosis, characterization of femoral head collapse is important in staging disease progression and planning treatment. Few prior studies have quantitatively compared the ability of sagittal and coronal MR images to detect femoral head collapse. We hypothesized that sagittal MR images show a greater degree and angular span of femoral head collapse than coronal images. We reviewed 38 hip MRI scans of nontraumatic femoral head osteonecrosis from 34 pediatric patients. In both sagittal and coronal images, the maximal extent and angular location along with the angular span of the femoral head collapse were measured. Differences were evaluated using a paired t-test. The extent of bone and cartilage loss from the femoral head was evaluated. Sagittal MR images showed 29% maximal femoral head radius collapse, whereas coronal images showed 16% collapse (P<0.001). Sagittal images showed a larger angular span of collapse (115 ) than coronal images (55 , P<0.001). Sagittal images showed greater epiphyseal bone loss in the anterior than in the posterior portion (P<0.001), whereas coronal images did not show a significant difference in bone loss between the medial and lateral portion (P=0.32). Sagittal images show greater femoral head collapse than coronal images in nontraumatic femoral head osteonecrosis. (orig.)

  17. Fixed sagittal plane imbalance.

    Science.gov (United States)

    Savage, Jason W; Patel, Alpesh A

    2014-12-01

    Study Design Literature review. Objective To discuss the evaluation and management of fixed sagittal plane imbalance. Methods A comprehensive literature review was performed on the preoperative evaluation of patients with sagittal plane malalignment, as well as the surgical strategies to address sagittal plane deformity. Results Sagittal plane imbalance is often caused by de novo scoliosis or iatrogenic flat back deformity. Understanding the etiology and magnitude of sagittal malalignment is crucial in realignment planning. Objective parameters have been developed to guide surgeons in determining how much correction is needed to achieve favorable outcomes. Currently, the goals of surgery are to restore a sagittal vertical axis Sagittal plane malalignment is an increasingly recognized cause of pain and disability. Treatment of sagittal plane imbalance varies according to the etiology, location, and severity of the deformity. Fixed sagittal malalignment often requires complex reconstructive procedures that include osteotomy correction. Reestablishing harmonious spinopelvic alignment is associated with significant improvement in health-related quality-of-life outcome measures and patient satisfaction.

  18. Additional merit of coronal STIR imaging for MR imaging of lumbar spine

    Directory of Open Access Journals (Sweden)

    Ranjana Gupta

    2015-01-01

    Full Text Available Introduction: Back pain is a common clinical problem and is the frequent complaint for referral of lumbar spine magnetic resonance imaging (MRI. Coronal short tau inversion recovery sequence (STIR can provide diagnostically significant information in small percentage of patients. Materials and Methods: MRI examinations of a total of 350 patients were retrospectively included in the study. MR sequences were evaluated in two settings. One radiologist evaluated sagittal and axial images only, while another radiologist evaluated all sequences, including coronal STIR sequence. After recording the diagnoses, we compared the MRI findings in two subsets of patients to evaluate additional merit of coronal STIR imaging. Results: With addition of coronal STIR imaging, significant findings were observed in 24 subjects (6.8%. Twenty-one of these subjects were considered to be normal on other sequences and in three subjects diagnosis was changed with the addition of coronal STIR. Additional diagnoses on STIR included sacroiliitis, sacroiliac joint degenerative disease, sacral stress/insufficiency fracture/Looser′s zones, muscular sprain and atypical appendicitis. Conclusion: Coronal STIR imaging can provide additional diagnoses in a small percentage of patients presenting for lumbar spine MRI for back pain. Therefore, it should be included in the routine protocol for MR imaging of lumbar spine.

  19. CHANGES IN THE SAGITTAL BALANCE IN CONGENITAL SCOLIOSIS CORRECTION SURGERY

    Directory of Open Access Journals (Sweden)

    José Antonio Mancuso Filho

    Full Text Available ABSTRACT Objective: This study aimed to determine whether surgery leads to changes in sagittal balance in patients with congenital scoliosis. Methods: We retrospectively reviewed all cases of scoliosis operated in a tertiary hospital between January 2009 and January 2013. In all cases the deformity in the coronal and sagittal planes, kyphosis, and lordosis were measured, using the Cobb method, and spinopelvic parameters: pelvic incidence (PI, sacral slope (SS, and pelvic tilt (PT. Results A hundred and eleven medical records were analyzed, but the sample resulted in 10 patients, six of whom were females (60%. The average age was 13.4 years. In the comparative analysis between pre and postoperative, only the coronal deformity (12.37; CI 95% [7.88-16.86]; p<0.001, the sagittal deformity (12.71; CI 95% [4.21-21.22]; p=0.011, and the lumbar lordosis (9.9; CI 95% [0.38-19.42]; p=0.043 showed significant change. Conclusion: There was no change in the spinopelvic parameters of patients with congenital scoliosis undergoing surgery at IOF-FMUSP between 2009 and 2013; however, it was observed decrease in lumbar lordosis, and deformity angle in the sagittal and coronal planes.

  20. Lenke 1型青少年特发性脊柱侧弯脊柱-骨盆矢状位与冠状位参数的相关性%Correlation analysis between the sagittal and coronal parameters of spino-pelvic in Lenke type 1 adolescent idiopathic scoliosis

    Institute of Scientific and Technical Information of China (English)

    胡攀攀; 于淼; 刘晓光; 陈仲强; 刘忠军

    2015-01-01

    Objective:To explore the relationship between spino-pelvic sagittal and coronal parameters in Lenke 1 group of adolescent idiopathic scoliosis (AIS).Methods:The subjects were retrospectively col-lected from 2005 to 2013.On the posteroanterior and lateral radiographs, apical vertebra ( AV) , Cobb an-gle of main thoracic curve (MT), pelvic incidence (PI), C7 translation ratio (C7TR) and other sagittal parameters were measured and recorded.Comparison and correlation studies were conducted between these parameters using specific softwares.Results: In the study, 51 subjects, including 18 males and 33 fe-males, were recruited, aged (14.9 ±2.0) years averagely.The apical vertebra ranged from T7 to T11,with mean MT being 49.6闭±16.7闭, and mean PI 44.7°±6.7°.Significant correlation existed between PI and PT, SS, LL, as well as between LL and SS, TK ( P <0.05) .Significant differences were found in TK, LL and SS among the different LM groups, but no difference in the other sagittal parameters.AV had no significant correlation with any sagittal parameter.MT was significantly correlated with TK, LL and SS, but its correlation with PI was not significant.Conclusion:Most of sagittal parameters were significantly corre-lated in Lenke 1 adolescent idiopathic scoliosis, forming a regulation chain of spine-pelvic sagittal balance on the basis of PI.Significant correlation exists between some sagittal and coronal parameters.%目的:探索Lenke 1型青少年特发性脊柱侧弯( adolescent idiopathic scoliosis, AIS)患者的脊柱-骨盆矢状位参数与冠状位参数的相关性。方法:回顾2005年4月至2013年11月北京大学第三医院诊治的Lenke 1型AIS患者,在正、侧位片上测量和记录顶锥(apical vertebra, AV)位置、主胸弯Cobb角(main thoracic, MT),以及骨盆入射角(pelvic incidence, PI)、C7转移比值(C7 translation ratio, C7TR)等矢状位参数,运用统计软件进行参数间的比较和相关

  1. Effect of pedicle subtraction osteotomy and Smith-Peterson osteotomy on coronal and sagittal balance restoration in patients with degenerative kyphoscoliosis%比较经椎弓根与Smith-Peterson截骨对退变性侧后凸畸形冠矢状面平衡重建的影响

    Institute of Scientific and Technical Information of China (English)

    朱锋; 鲍虹达; 邱勇; 刘臻; 毛赛虎; 朱泽章; 何守玉; 王斌

    2014-01-01

    Objective To compare the restoration of both coronal and sagittal balance following pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) for degenerative kyphoscoliosis.Methods Data of 47 patients with degenerative kyphoscoliosis,who underwent PSO or SPO from May 2007 to November 2011 in our center,were retrospectively analyzed.There were 25 cases of PSO and 22 of SPO.Long-cassette standing upright postero-anterior and lateral radiographs of the spine and pelvis were taken before,two weeks after surgeries and during follow-ups.The pre-,post-operative and follow-up parameters including Cobb angle,trunk shift (TS),apical vertebra translation (AVT),sagittal vertical axis (SVA),thoracic kyphosis (TK),lumbar lordosis (LL),pelvic incidence (PI),sacral slope (SS) and pelvic tilt (PT) were measured.Results The pre-operative parameters were matched between SPO and PSO groups except significantly larger TS in PSO group.Only SVA showed significant difference between the two groups postoperatively.No significant differences in parameters were observed between the two groups at the last follow-up.Significant differences were observed in terms of the improvement of Cobb angle,AVT,SVA,LL,PT and SS.TS in PSO decreased from 37.21 mm preoperatively to 24.67 mm postoperatively and it decreased to 21.69 mm at last follow-up.TS in SPO increased from 18.91 mm preoperatively to 37.43 mm postoperatively and it decreased to 17.84 mm at last follow-up.Conclusion Coronal and sagittal balance of patients with degenerative kyphoscoliosis can be well restored by both SPO and PSO despite different indications.Overcorrection of SVA is often seen in PSO group while the coronal balance in SPO group may not be well restored post-operatively which may attribute to post-operative posture.The postoperative imbalance of both coronal and sagittal plain could be corrected spontaneously during follow-ups.%目的 比较经椎弓根椎体截骨(pedicle subtraction osteotomy

  2. Coronal dynamics

    Science.gov (United States)

    Nakariakov, V. M.

    2007-07-01

    The lectures present the foundation of solar coronal physics with the main emphasis on the MHD theory and on wave and oscillatory phenomena. We discuss major challenges of the modern coronal physics; the main plasma structures observed in the corona and the conditions for their equilibrium; phenomenology of large scale long period oscillatory coronal phenomena and their theoretical modelling as MHD waves. The possibility of the remote diagnostics of coronal plasmas with the use of MHD oscillations is demonstrated.

  3. Grading Anterior Cruciate Ligament Graft Injury after Ligament Reconstruction Surgery: Diagnostic Efficacy of Oblique Coronal MR Imaging of the Knee

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sung Gyu; Hong, Sung Hwan; Choi, Ja Young; Jun, Woo Sun; Choi, Jung Ah; Park, Eun Ah; Kang, Heung Sik; Kwon, Jong Won [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2008-04-15

    Objective : The purpose of this study was to evaluate the diagnostic efficacy of using additional oblique coronal MRI of the knee for grading anterior cruciate ligament (ACL) graft injury after ligament reconstruction surgery. Materials and Methods : We retrospectively reviewed 51 consecutive MR knee examinations of 48 patients who underwent both ACL reconstruction and follow-up arthroscopy. The MR examinations included the orthogonal axial, sagittal, coronal images and the oblique coronal T2-weighted images, which were oriented in parallel with the course of the femoral intercondylar roof. Two radiologists independently evaluated the status of the ACL grafts with using the routine knee MRI and then with adding the oblique coronal imaging. The severity of ACL graft injury was graded using a 3-point system from MR images as intact, partial tear or complete tear, and the results were compared with the arthroscopic results. Weighted kappa statistics were used to analyze the diagnostic accuracies of the knee MRI with and without the additional oblique coronal imaging. For each evaluation, the observers reported a confidence level for grading the ACL graft injuries in the two imaging groups. Result : The weighted kappa values according to the routine knee MRI were 0.555 (reader 1) and 0.515 (reader 2). The inclusion of additional oblique coronal imaging increased the weighted kappa values to 0.666 (reader 1) and 0.611 (reader 2). The mean confidence levels by each reader were significantly higher (p < 0.01, paired t-test) with the additional oblique coronal imaging than by using the routine knee MRI alone. Conclusion : The additional use of oblique coronal MRI of the knee improves both the diagnostic accuracy and confidence for grading ACL graft injury.

  4. Determination of contact force at facet joint with different sagittal orientation under shearing loads:a finite element analysis

    Institute of Scientific and Technical Information of China (English)

    刘耀升; 陈其昕; 刘蜀彬

    2008-01-01

    with different facet joint angle.[Conclusion]The spatial orientation and geometric forms of the coronal facet articular surfaces are more effective in restricting motion in transversal and sagittal planes while assuming a minor role in resisting axial force or motion than sagittal facet articular surface.It Was presumed that anterior shear force play a more prominent contribution on the degeneration of the facet joint with coronal articular surface compared with posterior shear force.

  5. ODONTOID PROCESS HYPOPLASIA AND BIPARTITE ATLAS ASSOCIATED WITH ATLANTO-AXIAL INSTABILITY

    Directory of Open Access Journals (Sweden)

    Luis Miguel Sousa Marques

    Full Text Available ABSTRACT Surgical treatment of craniocervical junction pathology has evolved considerably in recent years with the implementation of short fixation techniques rather than long occipito-cervical fixation (sub-axial. It is often difficult and sometimes misleading to determine the particular bone and vascular features (high riding vertebral artery, for instance using only the conventional images in three orthogonal planes (axial, sagittal and coronal. The authors describe a rare clinical case of congenital malformation of the craniovertebral junction consisting of hypoplasia/agenesis of the odontoid process and bipartite atlas associated with atlantoaxial instability which was diagnosed late in life in a patient with a previous history of rheumatologic disease. The authors refer to the diagnostic process, including new imaging techniques, and three-dimensional multiplanar reconstruction. The authors also discuss the surgical technique and possible alternatives.

  6. The diagnostic value of the sagittal multiplanar reconstruction CT images for nasal bone fractures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.H. [Department of Radiology, Korea University Ansan Hospital, 516 Gojan1-dong, Danwon-gu, Ansan-si, Gyunggi-do, 425-707 (Korea, Republic of); Seo, H.S., E-mail: seohs@korea.ac.k [Department of Radiology, Korea University Ansan Hospital, 516 Gojan1-dong, Danwon-gu, Ansan-si, Gyunggi-do, 425-707 (Korea, Republic of); Kim, A.-Y.; Lee, Y.S. [Department of Radiology, Dongguk University International Hospital, Gyunggi-do (Korea, Republic of); Lee, Y.H. [Department of Radiology, Korea University Ansan Hospital, 516 Gojan1-dong, Danwon-gu, Ansan-si, Gyunggi-do, 425-707 (Korea, Republic of); Suh, S.-I. [Department of Diagnostic Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, D.H. [Department of Radiology, Seoul Medical Center, Seoul (Korea, Republic of)

    2010-04-15

    Aim: To compare the diagnostic performance of sagittal multiplanar reconstruction (MPR) images and axial images for the detection of a nasal bone fracture. Materials and methods: This prospective study included 533 consecutive patients who underwent three-dimensional images with 64-section multidetector-row CT for the evaluation of a facial bone fracture between June 2007 and May 2008 (366 males; 167 females; mean age +- standard deviation 31.1 +- 21.2 years; age range 1-92 years). Two observers independently scored the possibility of a nasal bone fracture on axial and sagittal images. Receiver operating characteristic (ROC) curve analysis was performed. Results: The Az values of the sagittal images were higher than those of the axial images for both observers (p = 0.002 and 0.010, respectively) with higher accuracy (p < 0.001 and 0.016, respectively). The sensitivities of sagittal images were superior to those of axial images, especially for type 1 simple nasal bone fractures with no or minimal displacement (observer 1, 98.6 versus 72.8%; observer 2, 84.9 versus 71%). Conclusion: Sagittal MPR facial bone CT images provided superior diagnostic performance, and their addition to axial images is useful for the evaluation of nasal bone fractures.

  7. Ponderomotive Acceleration in Coronal Loops

    Science.gov (United States)

    Dahlburg, R. B.; Laming, J. M.; Taylor, B. D.; Obenschain, K.

    2016-11-01

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  8. 3.0 T MR imaging of the ankle: Axial traction for morphological cartilage evaluation, quantitative T2 mapping and cartilage diffusion imaging—A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Jungmann, Pia M., E-mail: pia.jungmann@tum.de [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Baum, Thomas, E-mail: thomas.baum@tum.de [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Schaeffeler, Christoph, E-mail: schaeffeler@me.com [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Musculoskeletal Imaging, Kantonsspital Graubuenden, Loestrasse 170, CH-7000 Chur (Switzerland); Sauerschnig, Martin, E-mail: martin.sauerschnig@mri.tum.de [Department of Trauma Surgery, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Brucker, Peter U., E-mail: peter.brucker@lrz.tu-muenchen.de [Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Mann, Alexander, E-mail: abmann@onlinemed.de [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Department of Orthopaedic Sports Medicine, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Ganter, Carl, E-mail: cganter@tum.de [Department of Radiology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Ismaninger Strasse 22, 81675 Munich (Germany); Bieri, Oliver, E-mail: oliver.bieri@unibas.ch [Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Petersgraben 4, 4031 Basel (Switzerland); and others

    2015-08-15

    Highlights: • Axial traction is applicable during high resolution MR imaging of the ankle. • Axial traction during MR imaging oft the ankle improves cartilage surface delineation of the individual tibial and talar cartilage layer for better morphological evaluation without the need of intraarticular contrast agent application. • Coronal T1-weighted MR images with a driven equilibrium pulse performed best. • Axial traction during MR imaging of the ankle facilitates compartment discrimination for segmentation purposes resulting in better reproducibility. - Abstract: Purpose: To determine the impact of axial traction during high resolution 3.0 T MR imaging of the ankle on morphological assessment of articular cartilage and quantitative cartilage imaging parameters. Materials and Methods: MR images of n = 25 asymptomatic ankles were acquired with and without axial traction (6 kg). Coronal and sagittal T1-weighted (w) turbo spin echo (TSE) sequences with a driven equilibrium pulse and sagittal fat-saturated intermediate-w (IMfs) TSE sequences were acquired for morphological evaluation on a four-point scale (1 = best, 4 = worst). For quantitative assessment of cartilage degradation segmentation was performed on 2D multislice-multiecho (MSME) SE T2, steady-state free-precession (SSFP; n = 8) T2 and SSFP diffusion-weighted imaging (DWI; n = 8) images. Wilcoxon-tests and paired t-tests were used for statistical analysis. Results: With axial traction, joint space width increased significantly and delineation of cartilage surfaces was rated superior (P < 0.05). Cartilage surfaces were best visualized on coronal T1-w images (P < 0.05). Differences for cartilage matrix evaluation were smaller. Subchondral bone evaluation, motion artifacts and image quality were not significantly different between the acquisition methods (P > 0.05). T2 values were lower at the tibia than at the talus (P < 0.001). Reproducibility was better for images with axial traction. Conclusion

  9. The accuracy of intramedullary tibial guide of sagittal alignment of PCL-substituting total knee arthroplasty.

    Science.gov (United States)

    Han, Hyuk-Soo; Kang, Seung-Baik; Jo, Chris H; Kim, Sun-Hong; Lee, Jung-Ha

    2010-10-01

    Experimental and clinical studies on the accuracy of the intramedullary alignment method have produced different results, and few have addressed accuracy in the sagittal plane. Reported deviations are not only attributable to the alignment method but also to radiological errors. The purpose of this study was to evaluate the accuracy of the intramedullary alignment method in the sagittal plane using computed tomography (CT) and 3-dimensional imaging software. Thirty-one TKAs were performed using an intramedullary alignment method involving the insertion of a long 8-mm diameter rod into the medullary canal to the distal metaphysis of the tibia. All alignment instruments were set to achieve an ideal varus/valgus angle of 0° in the coronal plane and a tibial slope of 0° in the sagittal plane. The accuracy of the intramedullary alignment system was assessed by measuring the coronal tibial component angle and sagittal tibial slope angles, i.e., angles between the tibial anatomical axis and the tangent to the medial and lateral tibial plateau or the cut-surface. The mean coronal tibial component angle was 88.5° ± 1.2° and the mean tibial component slope in the sagittal plane was 1.6° ± 1.2° without anterior slope. Our intramedullary tibial alignment method, which involves passing an 8-mm diameter long rod through the tibial shaft isthmus, showed good accuracy (less than 3 degrees of variation and no anterior slope) in the sagittal plane in neutral or varus knees.

  10. Coronal magnetometry

    CERN Document Server

    Zhang, Jie; Bastian, Timothy

    2014-01-01

    This volume is a collection of research articles on the subject of the solar corona, and particularly, coronal magnetism. The book was motivated by the Workshop on Coronal Magnetism: Connecting Models to Data and the Corona to the Earth, which was held 21 - 23 May 2012 in Boulder, Colorado, USA. This workshop was attended by approximately 60 researchers. Articles from this meeting are contained in this topical issue, but the topical issue also contains contributions from researchers not present at the workshop. This volume is aimed at researchers and graduate students active in solar physics. Originally published in Solar Physics, Vol. 288, Issue 2, 2013 and Vol. 289, Issue 8, 2014.

  11. Radiographic Parameters in Adult Degenerative Scoliosis and Different Parameters Between Sagittal Balanced and Imbalanced ADS Patients.

    Science.gov (United States)

    Yang, Changwei; Yang, Mingyuan; Chen, Yuanyuan; Wei, Xianzhao; Ni, Haijian; Chen, Ziqiang; Li, Jingfeng; Bai, Yushu; Zhu, Xiaodong; Li, Ming

    2015-07-01

    A retrospective study. To summarize and describe the radiographic parameters of adult degenerative scoliosis (ADS) and explore the radiological parameters which are significantly different in sagittal balanced and imbalanced ADS patients. ADS is the most common type of adult spinal deformity. However, no comprehensive description of radiographic parameters in ADS patients has been made, and few studies have been performed to explore which radiological parameters are significantly different between sagittal balanced and imbalanced ADS patients. Medical records of ADS patients in our outpatient clinic from January 2012 to January 2014 were reviewed. Demographic data including age and sex, and radiographic data including the coronal Cobb angle, location of apical vertebra/disc, convexity of the curve, degree of apical vertebra rotation, curve segments, thoracic kyphosis (TK), lumbar lordosis (LL), thoracolumbar kyphosis (TL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), and PI minus LL (PI-LL) were reviewed to make comprehensive description of radiographic parameters of ADS. Furthermore, patients were divided into 2 groups according to whether the patients' sagittal plane was balanced: Group A (imbalanced, SVA > 5 cm) and Group B (balanced, SVA  ≤ 5 cm). Demographic and radiological parameters were compared between these 2 groups. A total of 99 patients were included in this study (Group A = 33 and Group B = 66; female = 83 and male = 16; sex ratio = 5:1). The median of age were 67 years (range: 41-92 years). The median of coronal Cobb angle and length of curve was 23 (range: 10-75°) and 5 segments (range: 3-7), respectively. The most common location of apical vertebra was at L2 to L3 (81%) and the median of degree of apical vertebra rotation was 2° (range: 1-3). Our study also showed significant correlations between coronal Cobb angle and curve segments (r = 0.23, P sagittal balance, there were significant

  12. Coronal Holes

    Directory of Open Access Journals (Sweden)

    Steven R. Cranmer

    2009-09-01

    Full Text Available Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations, and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are established in the extended corona. For example, the importance of kinetic plasma physics and turbulence in coronal holes has been affirmed by surprising measurements from the UVCS instrument on SOHO that heavy ions are heated to hundreds of times the temperatures of protons and electrons. These observations point to specific kinds of collisionless Alfvén wave damping (i.e., ion cyclotron resonance, but complete theoretical models do not yet exist. Despite our incomplete knowledge of the complex multi-scale plasma physics, however, much progress has been made toward the goal of understanding the mechanisms ultimately responsible for producing the observed properties of coronal holes.

  13. Coronal Holes

    CERN Document Server

    Cranmer, Steven R

    2009-01-01

    Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are establish...

  14. Standardized way for imaging of the sagittal spinal balance.

    Science.gov (United States)

    Morvan, Gérard; Mathieu, Philippe; Vuillemin, Valérie; Guerini, Henri; Bossard, Philippe; Zeitoun, Frédéric; Wybier, Marc

    2011-09-01

    Nowadays, conventional or digitalized teleradiography remains the most commonly used tool for the study of the sagittal balance, sometimes with secondary digitalization. The irradiation given by this technique is important and the photographic results are often poor. Some radiographic tables allow the realization of digitalized spinal radiographs by simultaneous translation of X-ray tube and receptor. EOS system is a new, very low dose system which gives good quality images, permits a simultaneous acquisition of upright frontal and sagittal views, is able to cover in the same time the spine and the lower limbs and study the axial plane on 3D envelope reconstructions. In the future, this low dose system should take a great place in the study of the pelvispinal balance. On the lateral view, several pelvic (incidence, pelvic tilt, sacral slope) and spinal (lumbar lordosis, thoracic kyphosis, Th9 sagittal offset, C7 plumb line) parameters are drawn to define the pelvispinal balance. All are interdependent. Pelvic incidence is an individual anatomic characteristic that corresponds to the "thickness" of the pelvis and governs the spinal balance. Pelvis and spine, in a harmonious whole, can be compared to an accordion, more or less compressed or stretched.

  15. Reproducibility of Abdominal Aortic Aneurysm Diameter Measurement and Growth Evaluation on Axial and Multiplanar Computed Tomography Reformations

    Energy Technology Data Exchange (ETDEWEB)

    Dugas, Alexandre; Therasse, Eric; Kauffmann, Claude; Tang, An [University of Montreal, Department of Radiology, Centre Hospitalier de l' Universite de Montreal (CHUM) and CHUM Research Center (CRCHUM) (Canada); Elkouri, Stephane [University of Montreal, Department of Surgery, Centre Hospitalier de l' Universite de Montreal (CHUM) (Canada); Nozza, Anna [Institut de Cardiologie de Montreal, Montreal Heart Institute Coordinating Centre (Canada); Giroux, Marie-France; Oliva, Vincent L.; Soulez, Gilles, E-mail: gilles.soulez.chum@ssss.gouv.qc.ca [University of Montreal, Department of Radiology, Centre Hospitalier de l' Universite de Montreal (CHUM) and CHUM Research Center (CRCHUM) (Canada)

    2012-08-15

    Purpose: To compare different methods measuring abdominal aortic aneurysm (AAA) maximal diameter (Dmax) and its progression on multidetector computed tomography (MDCT) scan. Materials and Methods: Forty AAA patients with two MDCT scans acquired at different times (baseline and follow-up) were included. Three observers measured AAA diameters by seven different methods: on axial images (anteroposterior, transverse, maximal, and short-axis views) and on multiplanar reformation (MPR) images (coronal, sagittal, and orthogonal views). Diameter measurement and progression were compared over time for the seven methods. Reproducibility of measurement methods was assessed by intraclass correlation coefficient (ICC) and Bland-Altman analysis. Results: Dmax, as measured on axial slices at baseline and follow-up (FU) MDCTs, was greater than that measured using the orthogonal method (p = 0.046 for baseline and 0.028 for FU), whereas Dmax measured with the orthogonal method was greater those using all other measurement methods (p-value range: <0.0001-0.03) but anteroposterior diameter (p = 0.18 baseline and 0.10 FU). The greatest interobserver ICCs were obtained for the orthogonal and transverse methods (0.972) at baseline and for the orthogonal and sagittal MPR images at FU (0.973 and 0.977). Interobserver ICC of the orthogonal method to document AAA progression was greater (ICC = 0.833) than measurements taken on axial images (ICC = 0.662-0.780) and single-plane MPR images (0.772-0.817). Conclusion: AAA Dmax measured on MDCT axial slices overestimates aneurysm size. Diameter as measured by the orthogonal method is more reproducible, especially to document AAA progression.

  16. Ponderomotive Acceleration in Coronal Loops

    CERN Document Server

    Dahlburg, R B; Taylor, B D; Obenschain, K

    2016-01-01

    Ponderomotive acceleration has been asserted to be a cause of the First Ionization Potential (FIP) effect, the by now well known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a "byproduct" of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of a coronal loops with an axial magnetic field from 0.005 Teslas to 0.02 Teslas and lengths from 25000 km to 75000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets...

  17. Conjoined lumbosacral nerve roots compromised by disk herniation: sagittal shoulder sign for the preoperative diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chang Ho [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Korea University College of Medicine, Department of Radiology, Anam Hospital, Seoul (Korea); Shin, Myung Jin; Kim, Sung Moon; Lee, Sang Hoon; Kim, Hee Kyung; Ryu, Jeong Ah [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea); Lee, Choon-Sung [University of Ulsan College of Medicine, Asan Medical Center, Department of Orthopedic Surgery, Seoul (Korea); Kim, Sam Soo [Kangwon National University College of Medicine, Department of Radiology, Kangwon (Korea)

    2008-03-15

    The objective was to determine the importance of the ''sagittal shoulder sign'' on magnetic resonance (MR) images for the diagnosis of conjoined lumbosacral nerve roots (CLNR) that are compromised by herniated disks. Magnetic resonance images of 11 patients (6 men and 5 women; age range, 25-71 years; average age, 48.7 years) with surgically proven CLNR, which was compromised by herniated disks, were retrospectively evaluated by two musculoskeletal radiologists. MR images were evaluated for the presence or absence of the sagittal shoulder sign - a vertical structure connecting two consecutive nerve roots and overlying disk on the sagittal MR images. The radiologists noted the type of accompanying disk herniation and bony spinal canal changes, as well as other characteristic MR features of CLNR, the common passage of two consecutive nerve roots through the neural foramen on axial MR images. The sagittal shoulder sign was identified with a mean frequency of 90.9% by the two observers (in 10 of 11 patients). The common passage of two consecutive nerve roots through the neural foramen on axial MR images was identified with a mean frequency of 59.1% (in 7 and 6 out of 11 patients, by observers 1 and 2, respectively). Good interobserver agreement for the sagittal shoulder sign was present (k = 0.621, p < 0.05). Observation of the sagittal shoulder sign may prove helpful for diagnosing CLNR in patients with disk herniation. In particular, this sign appears to be useful when there is no evidence of CLNR on axial MR images. (orig.)

  18. Avaliação ultrassonométrica da osteossíntese de compressão axial: estudo experimental Ultrasonometric evaluation of axial compression osteosinthesis: experimental study

    Directory of Open Access Journals (Sweden)

    Márcio Takey Bezuti

    2013-02-01

    Full Text Available OBJETIVO: Medir a velocidade de propagação do ultrassom (VU através de uma osteotomia transversal em tíbias de ovelha, antes e após a fixação com uma placa DCP. MÉTODOS: Foram utilizadas dez montagens de uma placa DCP com o segmento diafisário das tíbias, no qual era feita uma osteotomia transversal. Foi realizada a medida subaquática transversal, nos planos coronal e sagital, e axial da VU, no osso íntegro, nas montagens sem osteotomia e, depois, com osteotomia sem e com a compressão axial pela placa DCP; comparações estatísticas foram feitas ao nível de significância de 1% (pOBJECTIVE: To measure the ultrasound propagation velocity (UV through a tibial transverse osteotomy in sheep, before and after the fixation with a DCP plate. MATERIAL AND METHODS: Ten assemblies of a DCP plate with the diaphyseal segment of tibiae, in which a transverse osteotomy was made, were used. Both coronal and sagittal transverse and the axial UV were measured, first with the intact bone assembled with the plate and then with the uncompressed and compressed osteotomy; statistical comparisons were made at the 1% (p<0.01 level of significance. RESULTS: Compared with the intact bone assembly, axial UV significantly decreased with the addition of the osteotomy and significantly increased with compression, presenting the same behavior for the other modalities, although not significantly. DISCUSSION AND CONCLUSION: In accordance with the literature data on the ultrasonometric evaluation of fracture healing, underwater UV measurement was able to demonstrate the efficiency of DCP plate fixation. The authors conclude that the method has a potential for clinical application in the postoperative follow-up of DCP plate osteosinthesis, with a capability to demonstrate when it becomes ineffective. Laboratory investigation.

  19. The Relationship between T1 Sagittal Angle and Sagittal Balance: A Retrospective Study of 119 Healthy Volunteers

    OpenAIRE

    2016-01-01

    T1 sagittal angle has been reported to be used as a parameter for assessing sagittal balance and cervical lordosis. However, no study has been performed to explore the relationship between T1 sagittal angle and sagittal balance, and whether T1 sagittal angle could be used for osteotomy guidelines remains unknown. The aim of our study is to explore the relationship between T1 sagittal angle and sagittal balance, determine the predictors for T1 sagittal angle, and determine whether T1 sagittal ...

  20. Continence after posterior sagittal anorectoplasty.

    Science.gov (United States)

    Langemeijer, R A; Molenaar, J C

    1991-05-01

    Posterior sagittal anorectoplasty (PSARP) was introduced in 1982 by Peña and De Vries as a new operation for patients with a high anorectal malformation. The degree of postoperative continence is reported to be high. During the past decade, too, new insights have been gained into the embryology of anorectal malformations. Evaluation of PSARP in relation to current understanding of the development and anatomy of the anorectum and the pelvic floor has led us to conclude that optimal continence cannot be expected. Fifty patients with a high anorectal malformation underwent PSARP between June 1983 and May 1990. Postoperative follow-up consisted of anamnesis (subjective) and electrostimulation, defecography, and anorectal manometry (objective). All patients are alive, and all but one are being evaluated regularly. Subjectively, the majority of patients were more or less incontinent, with soiling of pants at least once a day. On the basis of objective criteria, virtually all patients appeared to be incontinent, and in only one patient was the mechanism of defecation almost unimpaired after PSARP. From this study, we conclude that although PSARP provides a good aesthetic result, patients will never acquire normal continence.

  1. Sagittal deformities of the spine: factors influencing the outcomes and complications.

    Science.gov (United States)

    Diebo, Bassel G; Henry, Jensen; Lafage, Virginie; Berjano, Pedro

    2015-01-01

    Degenerative changes have the potential to greatly disrupt the normal curvature of the spine, leading to sagittal malalignment. This phenomenon is often treated with operative modalities, such as osteotomies, though even with surgery, only one-third of patients may reach neutral alignment. Improvement in surgical outcomes may be achieved through better understanding of radiographic spino-pelvic parameters and their association with deformity. Methodical surgical planning, including selection of levels of instrumentation and site of the osteotomy, is crucial in determining the optimal plan for a patient's specific pathology and may minimize risk of developing postoperative proximal junctional kyphosis/failure. While sagittal alignment is essential in operative strategy, the coronal plane should not be overlooked, as it may affect the osteotomy technique. The concepts of sagittal balance and alignment are further complicated in patients with neuromuscular diseases such as Parkinson's disease, and appreciation of the interplay between anatomic and postural deformities is necessary to properly treat these patients. Finally, given the importance of sagittal alignment and the role of osteotomies in treatment for deformity, the need for future research becomes apparent. Novel intraoperative measurement techniques and three-dimensional analysis of the spine may allow for vastly improved operative correction. Furthermore, awareness of the relationship between alignment and balance, the soft tissue envelope, and compensatory mechanisms will provide a more comprehensive conception of the nature of spinal deformity and the modalities with which it is treated.

  2. Axial myopathy

    DEFF Research Database (Denmark)

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    musculature involvement in the majority of myopathies in which paraspinal musculature was examined. Even in diseases named after a certain pattern of non-axial muscle affection, such as facioscapulohumeral and limb girdle muscular dystrophies, affection of the axial musculature was often severe and early...

  3. The Relationship between T1 Sagittal Angle and Sagittal Balance: A Retrospective Study of 119 Healthy Volunteers.

    Science.gov (United States)

    Yang, Mingyuan; Yang, Changwei; Ni, Haijian; Zhao, Yuechao; Li, Ming

    2016-01-01

    T1 sagittal angle has been reported to be used as a parameter for assessing sagittal balance and cervical lordosis. However, no study has been performed to explore the relationship between T1 sagittal angle and sagittal balance, and whether T1 sagittal angle could be used for osteotomy guidelines remains unknown. The aim of our study is to explore the relationship between T1 sagittal angle and sagittal balance, determine the predictors for T1 sagittal angle, and determine whether T1 sagittal angle could be used for osteotomy guidelines to restore sagittal balance. Medical records of healthy volunteers in our outpatient clinic from January 2014 to August 2015 were reviewed, and their standing full-spine lateral radiographs were evaluated. Demographic and radiological parameters were collected and analyzed, including age, gender, T1 sagittal angle, maxTK, maxLL, SS, PT, and PI. Correlation coefficients between T1 sagittal angle and other spinopelvic parameters were determined. In addition, multiple regression analysis was performed to establish predictive radiographic parameters for T1 sagittal angle as the primary contributors. A total of 119 healthy volunteers were recruited in our study with a mean age of 34.7 years. It was found that T1 sagittal angle was correlated with maxTK with very good significance (r = 0.697, Psagittal angle could be predicted by using the following regression equation: T1 sagittal angle = 0.6 * maxTK-0.2 * maxLL + 8. In the healthy population, T1 sagittal angle could be considered as a useful parameter for sagittal balance; however, it could not be thoroughly replaced for SVA. maxTK was the primary contributor to T1 sagittal angle. According to this equation, we could restore sagittal balance by surgically changing thoracic kyphosis and lumbar lordosis, which could serve as a guideline for osteotomy.

  4. Significance of sagittal reformations in routine thoracic and abdominal multislice CT studies for detecting osteoporotic fractures and other spine abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Dirk; Bauer, Jan S.; Zeile, Martin; Rummeny, Ernst J. [Klinikum Rechts der Isar, TU Muenchen, Department of Radiology, Muenchen (Germany); Link, Thomas M. [Musculoskeletal and Quantitative Imaging Research, UCSF, Department of Radiology, San Francisco, CA (United States)

    2008-08-15

    The purpose was to assess osteoporotic vertebral fractures and other spinal lesions in sagittal reformations obtained from routine multidetector computed tomography (MDCT) studies of the thorax and abdomen, to compare sagittal reformations with axial images in detecting these lesions and to investigate how frequently they were missed in the official radiology report. Routine abdominal or thoracoabdominal MDCT using a standard protocol was performed in 112 postmenopausal women. Axial images and sagittal reformations were analyzed separately by two radiologists in consensus and were compared in order to evaluate how often spinal lesions could be detected. In addition the official radiology reports were assessed to determine how many of those abnormalities were identified. Spine abnormalities were visualized in 101/112 postmenopausal women. In 27 patients osteoporotic vertebral deformities were found; 6 of these were shown in the axial images, but none of these were diagnosed in the official radiology report. Additional abnormalities included degenerative disc disease, osteoarthritis of the facet joints, scoliosis, hemangiomas and bone metastases. In only 9/101 patients spine abnormalities were mentioned in the radiology report. Sagittal reformations of standard MDCT images provide important additional information on spinal abnormalities; in particular, osteoporotic vertebral deformities are substantially better detected. (orig.)

  5. Coronal influence on dynamos

    CERN Document Server

    Warnecke, Jörn

    2013-01-01

    We report on turbulent dynamo simulations in a spherical wedge with an outer coronal layer. We apply a two-layer model where the lower layer represents the convection zone and the upper layer the solar corona. This setup is used to study the coronal influence on the dynamo action beneath the surface. Increasing the radial coronal extent gradually to three times the solar radius and changing the magnetic Reynolds number, we find that dynamo action benefits from the additional coronal extent in terms of higher magnetic energy in the saturated stage. The flux of magnetic helicity can play an important role in this context.

  6. Ellis-van Creveld Syndrome with Sagittal Craniosynostosis.

    Science.gov (United States)

    Fischer, Andrew S; Weathers, William M; Wolfswinkel, Erik M; Bollo, Robert J; Hollier, Larry H; Buchanan, Edward P

    2015-06-01

    Ellis-van Creveld syndrome (EVC) is a rare disorder (the incidence is estimated at around 7/1,000,000) characterized by the clinical tetrad of chondrodystrophy, polydactyly, ectodermal dysplasia, and cardiac anomalies. Sagittal synostosis is characterized by a dolichocephalic head shape resulting from premature fusion of the sagittal suture. Both are rare disorders, which have never been reported together. We present a case of EVC and sagittal synostosis. We report the clinical features of a Hispanic boy with EVC and sagittal craniosynostosis who underwent cranial vault remodeling. The presentation of this patient is gone over in detail. A never before reported case of EVC and sagittal synostosis is presented in detail.

  7. Contribution of thin slice (1 mm) oblique coronal proton density-weighted MR images for assessment of anteromedial and posterolateral bundle damage in anterior cruciate ligament injuries

    Energy Technology Data Exchange (ETDEWEB)

    Gokalp, Gokhan, E-mail: drgokhangokalp@yahoo.com [Department of Radiology, Uludag University Medical Faculty, Gorukle, Bursa (Turkey); Demirag, Burak, E-mail: bdemirag@uludag.edu.tr [Department of Orthopedy, Uludag University Medical Faculty, Gorukle, Bursa (Turkey); Nas, Omer Fatih, E-mail: omerfatihnas@gmail.com [Department of Radiology, Uludag University Medical Faculty, Gorukle, Bursa (Turkey); Aydemir, Mehmet Fatih, E-mail: fatiha@yahoo.com [Department of Orthopedy, Uludag University Medical Faculty, Gorukle, Bursa (Turkey); Yazici, Zeynep, E-mail: zyazici@uludag.edu.tr [Department of Radiology, Uludag University Medical Faculty, Gorukle, Bursa (Turkey)

    2012-09-15

    Purpose: To evaluate the diagnostic efficacy of using additional oblique coronal 1 mm proton density-weighted (PDW) MR imaging of the knee for detection and grading anterior cruciate ligament (ACL), anteromedial bundle (AMB) and posterolateral bundle (PLB) injuries. Materials and methods: We prospectively assessed preoperative MR images of 50 patients (36 men, 14 women; age range, 18–62 years). First, we compared the diagnostic performance of routine sagittal (3 mm) and additional oblique coronal images (1 mm) for ACL tears. Then, we compared the tear types (AMB or PLB) and grade presumed from oblique coronal MR imaging with arthroscopy. Results: Arthroscopy revealed ACL tear in 24 (48%) patients. There was significant difference between sagittal images and arthroscopy results for ACL tear recognition (p < 0.001). No significant difference was detected for oblique coronal images when compared with arthroscopy results (p = 0.180). Sensitivity and specificity values for ACL tear diagnosis were 37.04% and 95.65% for sagittal images; 74.07% and 91.30% for oblique coronal images. There was no significant difference between arthroscopy and oblique coronal MR images in grading AMB and PLB injuries (p > 0.05). Conclusion: Addition of thin slice oblique coronal images to conventional sequences could better contribute to better verifying the presence of ACL tear and in determining its grade.

  8. The sagittal pelvic thickness: a determining parameter for the regulation of the sagittal spinopelvic balance.

    Science.gov (United States)

    Jean, Legaye

    2013-01-01

    Objective. To propose and validate a dimensional parameter, the sagittal pelvic thickness (SPT) (distance between the middle point of the upper sacral plate and the femoral heads axis, expressed as a ratio with the length of the upper plate of S1: (SPT/S1) for the analysis of the sagittal balance of the pelvispinal unit. Methods. The parameters were analysed on standing radiographic imaging and compared for normal, low back pain, children, and spondylolysis cases. Results. Values of SPT/S1 were observed significantly higher in high grade spondylolysis populations and in children (3,5 and 3,7) than in normal population (3,3). A geometrical connection with the classical angular parameters validated SPT/S1. Conclusion. SPT/S1 was considered reflecting the lever arm of action of spinopelvic muscles and ligaments and describing the ability of a subject to compensate a sagittal unbalance. It was proposed as an anatomical and functional pelvic parameter.

  9. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  10. Coronal Mass Ejections

    Science.gov (United States)

    Crooker, Nancy; Joselyn, Jo Ann; Feynman, Joan

    The early 1970's can be said to mark the beginning of The Enlightenment in the history of the Space Age, literally as well as by analogy to European history. Instruments blinded by Earth's atmosphere were lifted above and, for the first time, saw clearly and continuously the ethereal white light and sparkling x-rays from the solar corona. From these two bands of the light spectrum came images of coronal mass ejections and coronal holes, respectively. But whereas coronal holes were immediately identified as the source of high-speed solar wind streams, at first coronal mass ejections were greeted only by a sense of wonder. It took years of research to identify their signatures in the solar wind before the fastest ones could be identified with the well-known shock disturbances that cause the most violent space storms.

  11. Mechanisms of Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma

    2006-06-01

    The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar corona. Recent observations show that Magnetic Carpet is a potential candidate for solar coronal heating.

  12. The Sagittal Pelvic Thickness: A Determining Parameter for the Regulation of the Sagittal Spinopelvic Balance

    OpenAIRE

    2013-01-01

    Objective. To propose and validate a dimensional parameter, the sagittal pelvic thickness (SPT) (distance between the middle point of the upper sacral plate and the femoral heads axis, expressed as a ratio with the length of the upper plate of S1: (SPT/S1) for the analysis of the sagittal balance of the pelvispinal unit. Methods. The parameters were analysed on standing radiographic imaging and compared for normal, low back pain, children, and spondylolysis cases. Results. Values of SPT/S1 we...

  13. Exploring the utility of axial lumbar MRI for automatic diagnosis of intervertebral disc abnormalities

    Science.gov (United States)

    Ghosh, Subarna; Chaudhary, Vipin; Dhillon, Gurmeet

    2013-03-01

    In this paper, we explore the importance of axial lumbar MRI slices for automatic detection of abnormalities. In the past, only the sagittal views were taken into account for lumbar CAD systems, ignoring the fact that a radiologist scans through the axial slices as well, to confirm the diagnosis and quantify various abnormalities like herniation and stenosis. Hence, we present an automatic diagnosis system from axial slices using CNN(Convolutional Neural Network) for dynamic feature extraction and classification of normal and abnormal lumbar discs. We show 80:81% accuracy (with a specificity of 85:29% and sensitivity of 75:56%) on 86 cases (391 discs) using only an axial slice for each disc, which implies the usefulness of axial views for automatic lumbar abnormality diagnosis in conjunction with sagittal views.

  14. Global Coronal Waves

    CERN Document Server

    Chen, P F

    2016-01-01

    After the {\\em Solar and Heliospheric Observatory} ({\\em SOHO}) was launched in 1996, the aboard Extreme Ultraviolet Imaging Telescope (EIT) observed a global coronal wave phenomenon, which was initially named "EIT wave" after the telescope. The bright fronts are immediately followed by expanding dimmings. It has been shown that the brightenings and dimmings are mainly due to plasma density increase and depletion, respectively. Such a spectacular phenomenon sparked long-lasting interest and debates. The debates were concentrated on two topics, one is about the driving source, and the other is about the nature of this wavelike phenomenon. The controversies are most probably because there may exist two types of large-scale coronal waves that were not well resolved before the {\\em Solar Dynamics Observatory} ({\\em SDO}) was launched: one is a piston-driven shock wave straddling over the erupting coronal mass ejection (CME), and the other is an apparently propagating front, which may correspond to the CME frontal...

  15. Occlusion of the pig superior sagittal sinus, bridging and cortical veins: multistep evolution of sinus-vein thrombosis.

    Science.gov (United States)

    Fries, G; Wallenfang, T; Hennen, J; Velthaus, M; Heimann, A; Schild, H; Perneczky, A; Kempski, O

    1992-07-01

    Cerebral sinus-vein thrombosis may lead to severe hemodynamic changes, elevated intracranial pressure (ICP), and brain edema. It is supposed that progression of the thrombus from the sinus into bridging and cortical veins plays a key role in the development of these pathophysiological changes, but this hypothesis lacks experimental proof. The aim of this study, using a novel animal model of sinus-vein thrombosis, was to evaluate the effects of a standardized occlusion of the superior sagittal sinus and its bridging and cortical veins on hemodynamic alterations, on brain water content, and on ICP in domestic pigs. In 10 animals, the middle third of the superior sagittal sinus was occluded with a catheter-guided balloon. Five of these pigs received an additional injection of 1 ml fibrin glue into the superior sagittal sinus anterior to the inflated balloon, leading to an obstruction of bridging and cortical veins. In five control animals the balloon was inserted but not inflated. Five pigs underwent cerebral angiography. Four hours after occlusion, the brains were frozen in liquid nitrogen, and coronal slices were examined for Evans blue dye extravasation, regional water content, and histological changes. Occlusion of the superior sagittal sinus alone did not affect ICP or cerebral perfusion pressure (CPP). The additional injection of fibrin glue caused an obstruction of cortical and bridging veins as well as severe increases in mean (+/- standard deviation) ICP to 49.4 +/- 14.3 mm Hg, compared with 8.3 +/- 4.5 mm Hg in sham-treated controls and 7.1 +/- 3.9 mm Hg in animals with occlusion of the superior sagittal sinus alone. There was also a steep fall in the mean CPP to 34.2 +/- 19.6 mm Hg compared with 96.4 +/- 13.8 mm Hg in the control group. White-matter water content anterior to the occlusion site was elevated to 81.9 +/- 3.7 gm/100 gm frozen weight in the fibrin group as compared to 70.7 +/- 2.2 gm/100 gm in controls. Posterior to the occlusion site, water

  16. FUNCTIONAL DISABILITY, SAGITTAL ALIGNMENT AND PELVIC BALANCE IN LUMBAR SPONDYLOLISTHESIS

    Directory of Open Access Journals (Sweden)

    Luis Muñiz Luna

    2016-03-01

    Full Text Available ABSTRACT Objectives: To demonstrate the recovery of lumbar sagittal pelvic alignment and sagittal pelvic balance after surgical reduction of lumbar spondylolisthesis and establish the benefits of the surgery for reduction and fixation of the lumbar spondylolisthesis with 360o circumferential arthrodesis for 2 surgical approaches by clinical and functional evaluation. Method: Eight patients with lumbar spondylolisthesis treated with surgical reduction and fixation of listhesis and segmental circumferential fusion with two surgical approaches were reviewed. They were evaluated before and after treatment with Oswestry, Visual Analogue for pain and Odom scales, performing radiographic measurement of lumbar sagittal alignment and pelvic sagittal balance with the technique of pelvic radius. Results: Oswestry scales and EVA reported improvement of symptoms after treatment in 8 cases; the Odom scale had six outstanding cases reported. The lumbar sagittal alignment presented a lumbosacral lordosis angle and a lumbopelvic lordosis angle reduced in 4 cases and increased in 4 other cases; pelvic sagittal balance increased the pelvic angle in 4 cases and decreased in 3 cases and the sacral translation of the hip axis to the promontory increased in 6 cases. Conclusion: The surgical procedure evaluated proved to be useful by modifying the lumbar sagittal alignment and the pelvic balance, besides reducing the symptoms, enabling the patient to have mobility and movement and the consequent satisfaction with the surgery.

  17. Metopic and sagittal synostosis in Greig cephalopolysyndactyly syndrome: five cases with intragenic mutations or complete deletions of GLI3.

    Science.gov (United States)

    Hurst, Jane A; Jenkins, Dagan; Vasudevan, Pradeep C; Kirchhoff, Maria; Skovby, Flemming; Rieubland, Claudine; Gallati, Sabina; Rittinger, Olaf; Kroisel, Peter M; Johnson, David; Biesecker, Leslie G; Wilkie, Andrew O M

    2011-07-01

    Greig cephalopolysyndactyly syndrome (GCPS) is a multiple congenital malformation characterised by limb and craniofacial anomalies, caused by heterozygous mutation or deletion of GLI3. We report four boys and a girl who were presented with trigonocephaly due to metopic synostosis, in association with pre- and post-axial polydactyly and cutaneous syndactyly of hands and feet. Two cases had additional sagittal synostosis. None had a family history of similar features. In all five children, the diagnosis of GCPS was confirmed by molecular analysis of GLI3 (two had intragenic mutations and three had complete gene deletions detected on array comparative genomic hybridisation), thus highlighting the importance of trigonocephaly or overt metopic or sagittal synostosis as a distinct presenting feature of GCPS. These observations confirm and extend a recently proposed association of intragenic GLI3 mutations with metopic synostosis; moreover, the three individuals with complete deletion of GLI3 were previously considered to have Carpenter syndrome, highlighting an important source of diagnostic confusion.

  18. Sagittal Balance Correction in Lateral Interbody Fusion for Degenerative Scoliosis

    Science.gov (United States)

    Gallizzi, Michael A.; Sheets, Charles; Smith, Benjamin T.; Isaacs, Robert E.; Eure, Megan; Brown, Christopher R.

    2016-01-01

    Background Sagittal balance restoration has been shown to be an important determinant of outcomes in corrective surgery for degenerative scoliosis. Lateral interbody fusion (LIF) is a less-invasive technique which permits the placement of a high lordosis interbody cage without risks associated with traditional anterior or transforaminal interbody techniques. Studies have shown improvement in lumbar lordosis following LIF, but only one other study has assessed sagittal balance in this population. The objective of this study is to evaluate the ability of LIF to restore sagittal balance in degenerative lumbar scoliosis. Methods Thirty-five patients who underwent LIF for degenerative thoracolumbar scoliosis from July 2013 to March 2014 by a single surgeon were included. Outcome measures included sagittal balance, lumbar lordosis, Cobb Angle, and segmental lordosis. Measures were evaluated pre-operative, immediately post-operatively, and at their last clinical follow-up. Repeated measures ANOVAs were used to assess the differences between pre-operative, first postoperative, and a follow-up visit. Results The average sagittal balance correction was not significantly different: 1.06cm from 5.79cm to 4.74cm forward. The average Cobb angle correction was 14.1 degrees from 21.6 to 5.5 degrees. The average change in global lumbar lordosis was found to be significantly different: 6.3 degrees from 28.9 to 35.2 degrees. Conclusions This study demonstrates that LIF reliably restores lordosis, but does not significantly improve sagittal balance. Despite this, patients had reliable improvement in pain and functionality suggesting that sagittal balance correction may not be as critical in scoliosis correction as previous studies have indicated. Clinical Relevance LIF does not significantly change sagittal balance; however, clinical improvement does not seem to be contingent upon sagittal balance correction in the degenerative scoliosis population. The DUHS IRB has determined this

  19. Coronal Mass Ejections

    CERN Document Server

    Kunow, H; Linker, J. A; Schwenn, R; Steiger, R

    2006-01-01

    It is well known that the Sun gravitationally controls the orbits of planets and minor bodies. Much less known, however, is the domain of plasma fields and charged particles in which the Sun governs a heliosphere out to a distance of about 15 billion kilometers. What forces activates the Sun to maintain this power? Coronal Mass Ejections (CMEs) and their descendants are the troops serving the Sun during high solar activity periods. This volume offers a comprehensive and integrated overview of our present knowledge and understanding of Coronal Mass Ejections (CMEs) and their descendants, Interplanetary CMEs (ICMEs). It results from a series of workshops held between 2000 and 2004. An international team of about sixty experimenters involved e.g. in the SOHO, ULYSSES, VOYAGER, PIONEER, HELIOS, WIND, IMP, and ACE missions, ground observers, and theoreticians worked jointly on interpreting the observations and developing new models for CME initiations, development, and interplanetary propagation. The book provides...

  20. Early proximal junctional failure in patients with preoperative sagittal imbalance.

    Science.gov (United States)

    Smith, Micah W; Annis, Prokopis; Lawrence, Brandon D; Daubs, Michael D; Brodke, Darrel S

    2013-10-01

    Study Type Retrospective review. Introduction Sagittal imbalance has been associated with lower health-related quality of life outcomes, and restoration of imbalance is associated with improved outcomes.123 The long constructs used in adult spinal deformity have potential consequences such as proximal junctional kyphosis (PJK). Clinically, the development of PJK may not be as important as failure of the construct or vertebrae at the proximal end. As PJK does not lead to worse clinical outcomes,45 we define the term early proximal junctional failure (EPJF) as fracture, implant failure, or myelopathy due to stenosis at the upper instrumental vertebra (UIV) or UIV + 1 within 6 months of surgery. Objective The purpose of this study is to report the incidence of EPJF in patients who are sagittally imbalanced preoperatively and to identify risk factors postoperatively that correlate with EPJF using commonly reported sagittal balance parameters. Methods We reviewed 197 patients with preoperative sagittal imbalance by at least one of the following: sagittal vertical axis more than 5 cm, global sagittal alignment more than 45 degrees, pelvic incidence-lumbar lordosis more than 10 degrees, or spine-sacral angle less than 120 degrees. Radiographic measurements also included proximal junctional angle, thoracic kyphosis, lumbar lordosis, pelvic parameters, and sagittal balance parameters/formulas, as well as UIV angle, UIV spinosacral angle, and UIV plumb line to assess as potential risk factors. EPJF incidence was calculated postoperatively for each of the accepted sagittal balance parameters/formulas. Results EPJF was observed in 49 of 197 patients (25%) with preoperative sagittal imbalance and was more common in fusions with UIV in the lower thoracic spine (TS) (35%) than in those with UIV in the upper TS (10%) or lumbar (25%) (p = 0.007). Of the 49 EPJF patients, 16 patients (33%) required revision surgery within the first year, for an overall early revision

  1. Sagittal Abdominal Diameter: Application in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Thaís Da Silva-Ferreira

    2014-05-01

    Full Text Available Excess visceral fat is associated with cardiovascular risk factors. Sagittal abdominal diameter (SAD has recently been highlighted as an indicator of abdominal obesity, and also may be useful in predicting cardiovascular risk. The purpose of the present study was to review the scientific literature on the use of SAD in adult nutritional assessment. A search was conducted for scientific articles in the following electronic databases: SciELO , MEDLINE (PubMed and Virtual Health Library. SAD is more associated with abdominal fat (especially visceral, and with different cardiovascular risk factors, such as, insulin resistance, blood pressure, and serum lipoproteins than the traditional methods of estimating adiposity, such as body mass index and waist-to-hip ratio. SAD can also be used in association with other anthropometric measures. There are still no cut-off limits established to classify SAD as yet. SAD can be an alternative measure to estimate visceral adiposity. However, the few studies on this diameter, and the lack of consensus on the anatomical site to measure SAD, are obstacles to establish cut-off limits to classify it.

  2. Lenke 1 and 5: changes in sagittal balance

    OpenAIRE

    2014-01-01

    OBJECTIVE: To assess in a cross-sectional study whether there are changes in sagittal balance in patients with adolescent idiopathic scoliosis Lenke types 1 and 5 compared with patients without pathology of the spine and compare the values of the parameters of normal subjects with the parameters found in the literature. METHODS: We measured the values of the parameters of sagittal balance of 21 patients with scoliosis and 14 patients without scoliosis in panoramic radiographs or simply c...

  3. Temporomandibular joint: true sagittal computed tomography with meniscus visualization

    Energy Technology Data Exchange (ETDEWEB)

    Sartorix, D.J.; Neumann, C.H.; Riley, R.W.

    1984-01-01

    Accessory patient support equipment was constructed that allows patient positioning for true sagittal projection of the temporomandibular joint using a GE 8800 CT/T scanner. Range of motion abnormalities, osseous alterations of the mandibular condyle and temporal bone, joint-space narrowing, and meniscal configuration may be demonstrated. The technique has potential advantages over other CT projections and sagittal reconstruction for evaluation of temporomandibular joint dysfunction.

  4. Light axial vector mesons

    CERN Document Server

    Chen, Kan; Liu, Xiang; Matsuki, Takayuki

    2015-01-01

    Inspired by the abundant experimental observation of axial vector states, we study whether the observed axial vector states can be categorized into the conventional axial vector meson family. In this paper we carry out analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial vector mesons, which are valuable to further experimental exploration of the observed and predicted axial vector mesons.

  5. Global sagittal axis: a step toward full-body assessment of sagittal plane deformity in the human body.

    Science.gov (United States)

    Diebo, Bassel G; Oren, Jonathan H; Challier, Vincent; Lafage, Renaud; Ferrero, Emmanuelle; Liu, Shian; Vira, Shaleen; Spiegel, Matthew Adam; Harris, Bradley Yates; Liabaud, Barthelemy; Henry, Jensen K; Errico, Thomas J; Schwab, Frank J; Lafage, Virginie

    2016-10-01

    OBJECTIVE Sagittal malalignment requires higher energy expenditure to maintain an erect posture. Because the clinical impact of sagittal alignment is affected by both the severity of the deformity and recruitment of compensatory mechanisms, it is important to investigate new parameters that reflect both disability level and compensatory mechanisms for all patients. This study investigated the clinical relevance of the global sagittal axis (GSA), a novel measure to evaluate the standing axis of the human body. METHODS This is a retrospective review of patients who underwent full-body radiographs and completed health-related quality of life (HRQOL) questionnaires: Oswestry Disability Index (ODI), Scoliosis Research Society-22, EuroQol-5D (EQ-5D), and the visual analog scale for back and leg pain. The GSA was defined as the angle formed by a line from the midpoint of the femoral condyles to the center of C-7, and a line from the midpoint between the femoral condyles to the posterior superior corner of the S-1 sacral endplate. After evaluating the correlation of GSA/HRQOL with sagittal parameters, linear regression models were generated to investigate how ODI and GSA related to radiographic parameters (T-1 pelvic angle, pelvic retroversion, knee flexion, and pelvic posterior translation). RESULTS One hundred forty-three patients (mean age 44 years) were included. The GSA correlated significantly with all HRQOL (up to r = 0.6 with EQ-5D) and radiographic parameters (up to r = 0.962 with sagittal vertical axis). Regression between ODI and sagittal radiographic parameters identified the GSA as an independent predictor (r = 0.517, r(2) = 0.267; p human body in the sagittal plane. The GSA correlated highly with spinopelvic and lower-extremities sagittal parameters and exhibited remarkable correlations with HRQOL, which exceeded other commonly used parameters.

  6. Coronal radiation belts

    CERN Document Server

    Hudson, H S; Frewen, S F N; DeRosa, M L

    2009-01-01

    The magnetic field of the solar corona has a large-scale dipole character, which maps into the bipolar field in the solar wind. Using standard representations of the coronal field, we show that high-energy ions can be trapped stably in these large-scale closed fields. The drift shells that describe the conservation of the third adiabatic invariant may have complicated geometries. Particles trapped in these zones would resemble the Van Allen Belts and could have detectable consequences. We discuss potential sources of trapped particles.

  7. Cervical spine alignment, sagittal deformity, and clinical implications: a review.

    Science.gov (United States)

    Scheer, Justin K; Tang, Jessica A; Smith, Justin S; Acosta, Frank L; Protopsaltis, Themistocles S; Blondel, Benjamin; Bess, Shay; Shaffrey, Christopher I; Deviren, Vedat; Lafage, Virginie; Schwab, Frank; Ames, Christopher P

    2013-08-01

    This paper is a narrative review of normal cervical alignment, methods for quantifying alignment, and how alignment is associated with cervical deformity, myelopathy, and adjacent-segment disease (ASD), with discussions of health-related quality of life (HRQOL). Popular methods currently used to quantify cervical alignment are discussed including cervical lordosis, sagittal vertical axis, and horizontal gaze with the chin-brow to vertical angle. Cervical deformity is examined in detail as deformities localized to the cervical spine affect, and are affected by, other parameters of the spine in preserving global sagittal alignment. An evolving trend is defining cervical sagittal alignment. Evidence from a few recent studies suggests correlations between radiographic parameters in the cervical spine and HRQOL. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is critical. The article details mechanisms by which cervical kyphotic deformity potentially leads to ASD and discusses previous studies that suggest how postoperative sagittal malalignment may promote ASD. Further clinical studies are needed to explore the relationship of cervical malalignment and the development of ASD. Sagittal alignment of the cervical spine may play a substantial role in the development of cervical myelopathy as cervical deformity can lead to spinal cord compression and cord tension. Surgical correction of cervical myelopathy should always take into consideration cervical sagittal alignment, as decompression alone may not decrease cord tension induced by kyphosis. Awareness of the development of postlaminectomy kyphosis is critical as it relates to cervical myelopathy. The future direction of cervical deformity correction should include a comprehensive approach in assessing global cervicalpelvic relationships. Just as understanding pelvic incidence as it relates to lumbar lordosis was crucial in building our knowledge of thoracolumbar deformities, T

  8. Coronal reconstruction of unenhanced abdominal CT for correct ureteral stone size classification

    Energy Technology Data Exchange (ETDEWEB)

    Berkovitz, Nadav; Simanovsky, Natalia; Hiller, Nurith [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Radiology, Jerusalem (Israel); Katz, Ran [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Urology, Jerusalem (Israel); Salama, Shaden [Hadassah Mount Scopus - Hebrew University Medical Center, Department of Emergency Medicine, Jerusalem (Israel)

    2010-05-15

    To determine whether size measurement of a urinary calculus in coronal reconstruction of computed tomography (CT) differs from stone size measured in the axial plane, and whether the difference alters clinical decision making. We retrospectively reviewed unenhanced CT examinations of 150 patients admitted to the emergency room (ER) with acute renal colic. Maximal ureteral calculus size was measured on axial slices and coronal reconstructions. Clinical significance was defined as an upgrading or downgrading of stone size according to accepted thresholds of treatment: {<=}5 mm, 6-9 mm and {>=}10 mm. There were 151 stones in 150 patients (male:female 115:34, mean age 41 years). Transverse stone diameters ranged from 1 to 11 mm (mean 4 mm). On coronal images, 56 (37%) stones were upgraded in severity; 46 (30%) from below 5 mm to 6 mm or more, and ten (7%) from 6-9 mm to 10 mm or more. Transverse measurement on the axial slices enabled correct categorization of 95 stones (63%). Transverse calculus measurement on axial slices often underestimates stone size and provides incorrect clinical classification of the true maximal stone diameter. Coronal reconstruction provides additional information in patients with renal colic that may alter treatment strategy. (orig.)

  9. Sagittal alignment of the cervical spine after neck injury.

    Science.gov (United States)

    Beltsios, Michail; Savvidou, Olga; Mitsiokapa, Evanthia A; Mavrogenis, Andreas F; Kaspiris, Angelos; Efstathopoulos, Nikolaos; Papagelopoulos, Panayiotis J

    2013-07-01

    The normal sagittal alignment of the cervical spine is lordotic and is affected by the posture of the head and neck. The question of whether loss of cervical lordosis is the result of muscle spasm after injury or a normal variation, and the clinical significance of such changes in sagittal profile of the cervical spine has been an issue of several studies. The purpose of this paper is to study the incidence of normal cervical lordosis and its changes after neck injury compared to the healthy population. We studied the lateral radiographs of the cervical spine of 60 patients with neck injury compared to 100 patients without a neck injury. Lateral radiographs were obtained in the standing or sitting position, and the curvature of the cervical spine was measured using the angle formed between the inferior end plates of the C2 and C7 vertebrae. In the patients without neck injury, lordotic and straight cervical spine sagittal alignment was observed in 36.5% each, double curvature in 17%, and kyphotic in 10%. In the patients with neck injury, lordotic sagittal alignment was observed in 36%, straight in 34%, double curvature in 26% and kyphotic in 4%. No significant difference between the two groups regarding all types of sagittal alignment of the cervical spine was found (p > 0.100). The alterations in normal cervical lordosis in patients with neck injury must be considered coincidental. These alterations should not be associated with muscle spasm caused by neck pain.

  10. Coronal Mass Ejections: Observations

    Directory of Open Access Journals (Sweden)

    David F. Webb

    2012-06-01

    Full Text Available Solar eruptive phenomena embrace a variety of eruptions, including flares, solar energetic particles, and radio bursts. Since the vast majority of these are associated with the eruption, development, and evolution of coronal mass ejections (CMEs, we focus on CME observations in this review. CMEs are a key aspect of coronal and interplanetary dynamics. They inject large quantities of mass and magnetic flux into the heliosphere, causing major transient disturbances. CMEs can drive interplanetary shocks, a key source of solar energetic particles and are known to be the major contributor to severe space weather at the Earth. Studies over the past decade using the data sets from (among others the SOHO, TRACE, Wind, ACE, STEREO, and SDO spacecraft, along with ground-based instruments, have improved our knowledge of the origins and development of CMEs at the Sun and how they contribute to space weather at Earth. SOHO, launched in 1995, has provided us with almost continuous coverage of the solar corona over more than a complete solar cycle, and the heliospheric imagers SMEI (2003 – 2011 and the HIs (operating since early 2007 have provided us with the capability to image and track CMEs continually across the inner heliosphere. We review some key coronal properties of CMEs, their source regions and their propagation through the solar wind. The LASCO coronagraphs routinely observe CMEs launched along the Sun-Earth line as halo-like brightenings. STEREO also permits observing Earth-directed CMEs from three different viewpoints of increasing azimuthal separation, thereby enabling the estimation of their three-dimensional properties. These are important not only for space weather prediction purposes, but also for understanding the development and internal structure of CMEs since we view their source regions on the solar disk and can measure their in-situ characteristics along their axes. Included in our discussion of the recent developments in CME

  11. The coronal fricative problem

    Science.gov (United States)

    Dinnsen, Daniel A.; Dow, Michael C.; Gierut, Judith A.; Morrisette, Michele L.; Green, Christopher R.

    2013-01-01

    This paper examines a range of predicted versus attested error patterns involving coronal fricatives (e.g. [s, z, θ, ð]) as targets and repairs in the early sound systems of monolingual English-acquiring children. Typological results are reported from a cross-sectional study of 234 children with phonological delays (ages 3 years; 0 months to 7;9). Our analyses revealed different instantiations of a putative developmental conspiracy within and across children. Supplemental longitudinal evidence is also presented that replicates the cross-sectional results, offering further insight into the life-cycle of the conspiracy. Several of the observed typological anomalies are argued to follow from a modified version of Optimality Theory with Candidate Chains (McCarthy, 2007). PMID:24790247

  12. Surgical Correction of Nonsyndromic Sagittal Craniosynostosis: Concepts and Controversies.

    Science.gov (United States)

    Simpson, Andrew; Wong, Alison L; Bezuhly, Michael

    2017-01-01

    Sagittal craniosynostosis remains the most common type of isolated craniosynostosis, accounting for nearly half of all nonsyndromic cases. The clinical diagnosis is typically made on the basis of a scaphocephalic head shape and is confirmed by computed tomography or magnetic resonance imaging. The current review examines the major surgical options for correction of isolated sagittal craniosynostosis, including their complications and short- and long-term outcomes. Reconstructive techniques have benefited from advances in perioperative anesthesia monitoring and improved safety of blood transfusion. Although extensive calvarial remodeling is considered safe and may confer greater long-term skull shape correction and decreased neuropsychological sequelae, minimally invasive techniques, such as device-assisted expansion of the cranium continue to increase in popularity. This review underscores the need for additional prospective studies comparing different techniques to determine the optimal reconstructive approach for correction of sagittal craniosynostosis.

  13. Craniosynostosis of coronal suture in Twist1+/- mice occurs through endochondral ossification recapitulating the physiological closure of posterior frontal suture

    Directory of Open Access Journals (Sweden)

    Bjorn eBehr

    2011-07-01

    Full Text Available Craniosynostosis, the premature closure of cranial suture, is a pathologic condition that affects 1/2000 live births. Saethre-Chotzen syndrome is a genetic condition characterized by craniosynostosis. The Saethre-Chotzen syndrome, which is defined by loss-of-function mutations in the TWIST gene, is the second most prevalent craniosynostosis. Although much of the genetics and phenotypes in craniosynostosis syndromes is understood, less is known about the underlying ossification mechanism during suture closure. We have previously demonstrated that physiological closure of the posterior frontal (PF suture occurs through endochondral ossification. Moreover, we revealed that antagonizing canonical Wnt signaling in the sagittal suture leads to endochondral ossification of the suture mesenchyme and sagittal synostosis, presumably by inhibiting Twist1. Classic Saethre-Chotzen syndrome is characterized by coronal synostosis, and the haploinsufficient Twist1+/- mice represents a suitable model for studying this syndrome. Thus, we seeked to understand the underlying ossification process in coronal craniosynostosis in Twist1+/- mice. Our data indicate that coronal suture closure in Twist1+/- mice occurs between postnatal day 9 to 13 by endochondral ossification, as shown by histology, gene expression analysis and immunohistochemistry. In conclusion, this study reveals that coronal craniosynostosis in Twist1+/- mice occurs through endochondral ossification. Moreover, it suggests that haploinsufficency of Twist1 gene, a target of canonical Wnt-signaling, and inhibitor of chondrogenesis, mimics conditions of inactive canonical Wnt-signaling leading to craniosynostosis.

  14. Craniosynostosis of coronal suture in twist1 mice occurs through endochondral ossification recapitulating the physiological closure of posterior frontal suture.

    Science.gov (United States)

    Behr, Björn; Longaker, Michael T; Quarto, Natalina

    2011-01-01

    Craniosynostosis, the premature closure of cranial suture, is a pathologic condition that affects 1/2000 live births. Saethre-Chotzen syndrome is a genetic condition characterized by craniosynostosis. The Saethre-Chotzen syndrome, which is defined by loss-of-function mutations in the TWIST gene, is the second most prevalent craniosynostosis. Although much of the genetics and phenotypes in craniosynostosis syndromes is understood, less is known about the underlying ossification mechanism during suture closure. We have previously demonstrated that physiological closure of the posterior frontal suture occurs through endochondral ossification. Moreover, we revealed that antagonizing canonical Wnt-signaling in the sagittal suture leads to endochondral ossification of the suture mesenchyme and sagittal synostosis, presumably by inhibiting Twist1. Classic Saethre-Chotzen syndrome is characterized by coronal synostosis, and the haploinsufficient Twist1(+/-) mice represents a suitable model for studying this syndrome. Thus, we seeked to understand the underlying ossification process in coronal craniosynostosis in Twist1(+/-) mice. Our data indicate that coronal suture closure in Twist1(+/-) mice occurs between postnatal day 9 and 13 by endochondral ossification, as shown by histology, gene expression analysis, and immunohistochemistry. In conclusion, this study reveals that coronal craniosynostosis in Twist1(+/-) mice occurs through endochondral ossification. Moreover, it suggests that haploinsufficiency of Twist1 gene, a target of canonical Wnt-signaling, and inhibitor of chondrogenesis, mimics conditions of inactive canonical Wnt-signaling leading to craniosynostosis.

  15. Diffraction crystal for sagittally focusing x-rays

    Science.gov (United States)

    Ice, Gene E.; Sparks, Jr., Cullie J.

    1984-01-01

    The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

  16. Diffraction crystals for sagittally focusing x-rays

    Science.gov (United States)

    Ice, G.E.; Sparks, C.J. Jr.

    1982-06-07

    The invention is a new type of diffraction crystal designed for sagittally focusing photons of various energies. The invention is based on the discovery that such focusing is not obtainable with conventional crystals because of distortion resulting from anticlastic curvature. The new crystal comprises a monocrystalline base having a front face contoured for sagittally focusing photons and a back face provided with rigid, upstanding, stiffening ribs restricting anticlastic curvature. When mounted in a suitable bending device, the reflecting face of the crystal can be adjusted to focus photons having any one of a range of energies.

  17. An analysis of vertebral axial rotation in adolescent idiopathic scoliosis based on EOSTM%基于 EOSTM 的青少年特发性脊柱侧凸椎体轴面旋转分析

    Institute of Scientific and Technical Information of China (English)

    秦乐; 严福华; 杜联军; 师小凤

    2016-01-01

    目的:利用 EOS 影像系统分析青少年特发性脊柱侧凸( adolescent idiopathic scoliosis,AIS )患者的椎体轴面旋转角度与冠状面、矢状面和骨盆畸形间的关系。方法选择2015年9月至2016年2月,在我院拍摄的 EOS 脊柱全长 X 线片的 AIS 患者,共有49例纳入研究,使用 sterEOS 软件对脊柱全长 X 线片进行三维模型重建。根据主弯所在位置,获得冠状面 Cobb’s 角,轴面顶点椎体旋转、上椎旋转、末椎旋转、上椎椎体间轴面旋转和末椎椎体间轴面旋转角度,矢状面 T4~12后凸角和骨盆参数骨盆入射角、骨盆倾斜角。对各轴面旋转角度与冠状面 Cobb’s 角以及骨盆参数进行 Pearson 相关性分析。将胸主弯、胸腰段主弯和腰主弯的顶点椎体旋转角度分别与胸椎矢状面后凸角进行相关性分析。结果顶点椎体轴面旋转与 Cobb’s 角有较好的相关性(r=0.792,P<0.001),上椎旋转、末椎旋转、上椎椎体间轴面旋转和末椎椎体间轴面旋转分别与 Cobb’s 角有轻、中度的相关性(r=0.419,P=0.003;r=0.320,P=0.025;r=0.366,P<0.01;r=0.345,P=0.015)。除顶点椎体轴面旋转与骨盆倾斜角有轻度相关性外(r=0.330,P<0.021),其余脊柱轴面与骨盆参数均无明显相关性。主胸椎侧凸组、胸腰段侧凸组和腰椎侧凸组顶点椎体旋转角度与 T4~12后凸角均无明显相关性。结论椎体轴面旋转角度与脊柱冠状面 Cobb’s 角之间存在密切的联系,但可能与胸椎后凸角和骨盆畸形并无明显关系。%Objective To evaluate the axial vertebral rotation for their relations with the coronal and sagittal spine as well as pelvic deformity by EOS imaging system.Methods From September 2015 to February 2016, 49 patients with adolescent idiopathic scoliosis subjected to EOS X-ray examinations were enrolled in this study, followed by sterEOS 3 D reconstructions

  18. Lenke 1 and 5: changes in sagittal balance

    Directory of Open Access Journals (Sweden)

    Delson Valdemir Pessin

    2014-09-01

    Full Text Available OBJECTIVE: To assess in a cross-sectional study whether there are changes in sagittal balance in patients with adolescent idiopathic scoliosis Lenke types 1 and 5 compared with patients without pathology of the spine and compare the values of the parameters of normal subjects with the parameters found in the literature. METHODS: We measured the values of the parameters of sagittal balance of 21 patients with scoliosis and 14 patients without scoliosis in panoramic radiographs or simply collected data previously measured from the medical records. We compared the mean values of normal subjects, the mean values found in the literature, and the means between normal subjects and patients with scoliosis. For this, we used the Student t test. RESULTS: Using a confidence interval of 5% (p < 0.05 and the Student t test we obtained statistical significance in the comparison of two parameters of sagittal balance between normal subjects and patients with scoliosis. We observed similarities in the measurements of the average parameters of normal subjects with regard to the work already published. CONCLUSIONS: The adolescent idiopathic scoliosis causes changes in two parameters of sagittal balance with statistical significance but suggests changes in all other parameters. As for comparison with previously published work, the results were similar.

  19. Solar Coronal Plumes

    Directory of Open Access Journals (Sweden)

    Giannina Poletto

    2015-12-01

    Full Text Available Polar plumes are thin long ray-like structures that project beyond the limb of the Sun polar regions, maintaining their identity over distances of several solar radii. Plumes have been first observed in white-light (WL images of the Sun, but, with the advent of the space era, they have been identified also in X-ray and UV wavelengths (XUV and, possibly, even in in situ data. This review traces the history of plumes, from the time they have been first imaged, to the complex means by which nowadays we attempt to reconstruct their 3-D structure. Spectroscopic techniques allowed us also to infer the physical parameters of plumes and estimate their electron and kinetic temperatures and their densities. However, perhaps the most interesting problem we need to solve is the role they cover in the solar wind origin and acceleration: Does the solar wind emanate from plumes or from the ambient coronal hole wherein they are embedded? Do plumes have a role in solar wind acceleration and mass loading? Answers to these questions are still somewhat ambiguous and theoretical modeling does not provide definite answers either. Recent data, with an unprecedented high spatial and temporal resolution, provide new information on the fine structure of plumes, their temporal evolution and relationship with other transient phenomena that may shed further light on these elusive features.

  20. Sagittal spinal alignment in patients with lumbar disc herniation.

    Science.gov (United States)

    Endo, Kenji; Suzuki, Hidekazu; Tanaka, Hidetoshi; Kang, Yupeng; Yamamoto, Kengo

    2010-03-01

    A retrospective cross-sectional study was designed to evaluate total sagittal spinal alignment in patients with lumbar disc herniation (LDH) and healthy subjects. Abnormal sagittal spinal alignment could cause persistent low back pain in lumbar disease. Previous studies analyzed sciatic scoliotic list in patients with lumbar disc herniation; but there is little or no information on the relationship between sagittal alignment and subjective findings. The study subjects were 61 LDH patients and 60 age-matched healthy subjects. Preoperative and 6-month postoperatively lateral whole-spine standing radiographs were assessed for the distance between C7 plumb line and posterior superior corner on the top margin of S1 sagittal vertical axis (SVA), lumbar lordotic angle between the top margin of the first lumbar vertebra and first sacral vertebra (L1S1), pelvic tilting angle (PA), and pelvic morphologic angle (PRS1). Subjective symptoms were evaluated by the Japanese Orthopedic Association (JOA) score for lower back pain (nine points). The mean SVA value of the LDH group (32.7 +/- 46.5 mm, +/- SD) was significantly larger than that of the control (2.5 +/- 17.1 mm), while L1S1 was smaller (36.7 +/- 14.5 degrees ) and PA was larger (25.1 +/- 9.0 degrees ) in LDH than control group (49.0 +/- 10.0 degrees and 18.2 +/- 6.0 degrees , respectively). At 6 months after surgery, the malalignment recovered to almost the same level as the control group. SVA correlated with the subjective symptoms measured by the JOA score. Sagittal spinal alignment in LDH exhibits more anterior translation of the C7 plumb line, less lumbar lordosis, and a more vertical sacrum. Measurements of these spinal parameters allowed assessment of the pathophysiology of LDH.

  1. Numerical Simulation of DC Coronal Heating

    Science.gov (United States)

    Dahlburg, Russell B.; Einaudi, G.; Taylor, Brian D.; Ugarte-Urra, Ignacio; Warren, Harry; Rappazzo, A. F.; Velli, Marco

    2016-05-01

    Recent research on observational signatures of turbulent heating of a coronal loop will be discussed. The evolution of the loop is is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. HYPERION calculates the full energy cycle involving footpoint convection, magnetic reconnection, nonlinear thermal conduction and optically thin radiation. The footpoints of the loop magnetic field are convected by random photospheric motions. As a consequence the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is non-uniformly distributed so that only a fraction of thecoronal mass and volume gets heated at any time. Temperature and density are highly structured at scales which, in the solar corona, remain observationally unresolved: the plasma of the simulated loop is multi thermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Typical simulated coronal loops are 50000 km length and have axial magnetic field intensities ranging from 0.01 to 0.04 Tesla. To connect these simulations to observations the computed number densities and temperatures are used to synthesize the intensities expected in emission lines typically observed with the Extreme ultraviolet Imaging Spectrometer (EIS) on Hinode. These intensities are then employed to compute differential emission measure distributions, which are found to be very similar to those derived from observations of solar active regions.

  2. Coronal Seismology -- Achievements and Perspectives

    Science.gov (United States)

    Ruderman, Michael

    Coronal seismology is a new and fast developing branch of the solar physics. The main idea of coronal seismology is the same as of any branches of seismology: to determine basic properties of a medium using properties of waves propagating in this medium. The waves and oscillations in the solar corona are routinely observed in the late space missions. In our brief review we concentrate only on one of the most spectacular type of oscillations observed in the solar corona - the transverse oscillations of coronal magnetic loops. These oscillations were first observed by TRACE on 14 July 1998. At present there are a few dozens of similar observations. Shortly after the first observation of the coronal loop transverse oscillations they were interpreted as kink oscillations of magnetic tubes with the ends frozen in the dense photospheric plasma. The frequency of the kink oscillation is proportional to the magnetic field magnitude and inversely proportional to the tube length times the square root of the plasma density. This fact was used to estimate the magnetic field magnitude in the coronal loops. In 2004 the first simultaneous observation of the fundamental mode and first overtone of the coronal loop transverse oscillation was reported. If we model a coronal loop as a homogeneous magnetic tube, then the ratio of the frequencies of the first overtone and the fundamental mode should be equal to 2. However, the ratio of the observed frequencies was smaller than 2. This is related to the density variation along the loop. If we assume that the corona is isothermal and prescribe the loop shape (usually it is assumed that it has the shape of half-circle), then, using the ratio of the two frequencies, we can determine the temperature of the coronal plasma. The first observation of transverse oscillations of the coronal loops showed that they were strongly damped. This phenomenon was confirmed by the subsequent observations. At present, the most reliable candidate for the

  3. Geometry of solar coronal rays

    Science.gov (United States)

    Filippov, B. P.; Martsenyuk, O. V.; Platov, Yu. V.; Den, O. E.

    2016-02-01

    Coronal helmet streamers are the most prominent large-scale elements of the solar corona observed in white light during total solar eclipses. The base of the streamer is an arcade of loops located above a global polarity inversion line. At an altitude of 1-2 solar radii above the limb, the apices of the arches sharpen, forming cusp structures, above which narrow coronal rays are observed. Lyot coronagraphs, especially those on-board spacecrafts flying beyond the Earth's atmosphere, enable us to observe the corona continuously and at large distances. At distances of several solar radii, the streamers take the form of fairly narrow spokes that diverge radially from the Sun. This radial direction displays a continuous expansion of the corona into the surrounding space, and the formation of the solar wind. However, the solar magnetic field and solar rotation complicate the situation. The rotation curves radial streams into spiral ones, similar to water streams flowing from rotating tubes. The influence of the magnetic field is more complex and multifarious. A thorough study of coronal ray geometries shows that rays are frequently not radial and not straight. Coronal streamers frequently display a curvature whose direction in the meridional plane depends on the phase of the solar cycle. It is evident that this curvature is related to the geometry of the global solar magnetic field, which depends on the cycle phase. Equatorward deviations of coronal streamers at solar minima and poleward deviations at solar maxima can be interpreted as the effects of changes in the general topology of the global solar magnetic field. There are sporadic temporal changes in the coronal rays shape caused by remote coronal mass ejections (CMEs) propagating through the corona. This is also a manifestation of the influence of the magnetic field on plasma flows. The motion of a large-scale flux rope associated with a CME away from the Sun creates changes in the structure of surrounding field

  4. Ultraprecision machining of steep aspheric parts with large sagittal height

    Science.gov (United States)

    Mu, Lin; Zhao, Rui; Xin, Qiming

    2009-05-01

    Problems occurred during machining steep aspheric parts with large sagittal height on double-spindle diamond turning machine are presented and the main reasons of the problems are described. And methods of solving these problems are also suggested. When we machine steep aspheric parts with large sagittal height on a 2 axis diamond turning machine, we have such problems as difficult control of part edge accuracy, poor roughness and rapid wear of the cutting tool. The main reasons for these problems lie in: 1) Measurement. To make accurate measurements, the measurement range of the profilometer must fall within the sagittal heights of the aspheric parts, and the measurement angle must also meet the requirements, an insufficient measurement angle, for example, will have a big impact on the measurement and fabrication accuracy of such parts; and 2) Machine and tool, firstly, the diamond cutting tool will suffer a very big force when turning the edge section, resulting in bigger micro-vibration in the tool and tool post, thus affecting the part accuracy and surface roughness. Secondly, the machine itself has location errors in axes X and Z during the processing, leading to the severest destruction in the steep section of the aspheric part by their resultant force. Lastly, anisotropy of diamond cutting tool hardness. The indentation hardness of the diamond is maximum in the direction of of face (100) and the front clearance has the best strength at tool point in the direction of . When cutting a steep aspheric part with large sagittal height, a bigger included angle of the diamond tool point arc will be used, and there will be a more deviation from the lattice direction. So the tool hardness is consistently decreased, resulting in a rapid wear of the cutting tool when turning the steep section of the aspheric part, thus the accuracy and roughness in machining an aspheric part become more difficult to control. The paper is concluded with the solutions of turning steep

  5. Coronal Mass Ejections An Introduction

    CERN Document Server

    Howard, Timothy

    2011-01-01

    In times of growing technological sophistication and of our dependence on electronic technology, we are all affected by space weather. In its most extreme form, space weather can disrupt communications, damage and destroy spacecraft and power stations, and increase radiation exposure to astronauts and airline passengers. Major space weather events, called geomagnetic storms, are large disruptions in the Earth’s magnetic field brought about by the arrival of enormous magnetized plasma clouds from the Sun. Coronal mass ejections (CMEs) contain billions of tons of plasma and hurtle through space at speeds of several million miles per hour. Understanding coronal mass ejections and their impact on the Earth is of great interest to both the scientific and technological communities. This book provides an introduction to coronal mass ejections, including a history of their observation and scientific revelations, instruments and theory behind their detection and measurement, and the status quo of theories describing...

  6. Motion magnification in coronal seismology

    CERN Document Server

    Anfinogentov, Sergey

    2016-01-01

    We introduce a new method for the investigation of low-amplitude transverse oscillations of solar plasma non-uniformities, such as coronal loops, individual strands in coronal arcades, jets, prominence fibrils, polar plumes, and other contrast features, observed with imaging instruments. The method is based on the two-dimensional dual tree complex wavelet transform (DT$\\mathbb{C}$WT). It allows us to magnify transverse, in the plane-of-the-sky, quasi-periodic motions of contrast features in image sequences. The tests performed on the artificial data cubes imitating exponentially decaying, multi-periodic and frequency-modulated kink oscillations of coronal loops showed the effectiveness, reliability and robustness of this technique. The algorithm was found to give linear scaling of the magnified amplitudes with the original amplitudes provided they are sufficiently small. Also, the magnification is independent of the oscillation period in a broad range of the periods. The application of this technique to SDO/A...

  7. Spinal pedicle subtraction osteotomy for fixed sagittal imbalance patients.

    Science.gov (United States)

    Hyun, Seung-Jae; Kim, Yongjung J; Rhim, Seung-Chul

    2013-11-16

    In addressing spinal sagittal imbalance through a posterior approach, the surgeon now may choose from among a variety of osteotomy techniques. Posterior column osteotomies such as the facetectomy or Ponte or Smith-Petersen osteotomy provide the least correction, but can be used at multiple levels with minimal blood loss and a lower operative risk. Pedicle subtraction osteotomies provide nearly 3 times the per-level correction of Ponte/Smith-Petersen osteotomies; however, they carry increased technical demands, longer operative time, and greater blood loss and associated significant morbidity, including neurological injury. The literature focusing on pedicle subtraction osteotomy for fixed sagittal imbalance patients is reviewed. The long-term overall outcomes, surgical tips to reduce the complications and suggestions for their proper application are also provided.

  8. Temporomandibular joint computed tomography: development of a direct sagittal technique

    Energy Technology Data Exchange (ETDEWEB)

    van der Kuijl, B.; Vencken, L.M.; de Bont, L.G.; Boering, G. (Univ. of Groningen, (Netherlands))

    1990-12-01

    Radiology plays an important role in the diagnosis of temporomandibular disorders. Different techniques are used with computed tomography offering simultaneous imaging of bone and soft tissues. It is therefore suited for visualization of the articular disk and may be used in patients with suspected internal derangements and other disorders of the temporomandibular joint. Previous research suggests advantages to direct sagittal scanning, which requires special positioning of the patient and a sophisticated scanning technique. This study describes the development of a new technique of direct sagittal computed tomographic imaging of the temporomandibular joint using a specially designed patient table and internal light visor positioning. No structures other than the patient's head are involved in the imaging process, and misleading artifacts from the arm or the shoulder are eliminated. The use of the scanogram allows precise correction of the condylar axis and selection of exact slice level.

  9. Sagittal acoustic waves in phononic crystals: the k - dependent polarization

    Science.gov (United States)

    Manzanares-Martinez, Betsabe; Ramos-Mendieta, Felipe

    2007-03-01

    We have studied the longitudinal and shear contributions to the sagittal vibrations in phononic crystals of one and two dimensional periodicity. As is well known, pressure and shear waves couple to form the saggital oscillations. The question that guides our work is which of the two vibrations predominates in these waves. We demonstrate numerically that the contributions depend on the wave vector, in addition to the structural and material parameters. For calculations we have used a criterion of strain energy balance; the average of the pressure and shear contributions within the unitary cell is obtained. We present the polarization map of sagittal waves in an Epoxy/Sn superlattice and the band polarization for two arrays of cylindrical holes in epoxy. As we shall see the mixed modes can be either predominantly transverse or predominantly longitudinal.

  10. Coronal Fourier power spectra: implications for coronal seismology and coronal heating

    CERN Document Server

    Ireland, Jack; Inglis, Andrew R

    2014-01-01

    The dynamics of regions of the solar corona are investigated using Atmospheric Imaging Assembly (AIA) 171\\AA\\ and 193\\AA\\ data. The coronal emission from the quiet Sun, coronal loop footprints, coronal moss, and from above a sunspot is studied. It is shown that the mean Fourier power spectra in these regions can be described by a power law at lower frequencies that tails to flat spectrum at higher frequencies, plus a Gaussian-shaped contribution that varies depending on the region studied. This Fourier spectral shape is in contrast to the commonly-held assumption that coronal time-series are well described by the sum of a long time-scale background trend plus Gaussian-distributed noise, with some specific locations also showing an oscillatory signal. The implications of this discovery to the field of coronal seismology and the automated detections of oscillations are discussed. The power law contribution to the shape of the Fourier power spectrum is interpreted as being due to the summation of a distribution ...

  11. Risk factors affecting somatosensory function after sagittal split osteotomy

    DEFF Research Database (Denmark)

    Thygesen, Torben Henrik; Jensen, Allan Bardow; Helleberg, M;

    2008-01-01

    Purpose The aim of this study was to evaluate potential individual and intraoperative risk factors associated with bilateral sagittal split osteotomy (BSSO) and to correlate the findings with postoperative changes in somatosensory function. Patients and Methods A total of 18 men and 29 women (mean...... and free dissection of the inferior alveolar nerve during BSSO increased self-reported changes in lower lip sensation and lower lip tactile threshold after BSSO (P discrimination (P

  12. Early Proximal Junctional Failure in Patients with Preoperative Sagittal Imbalance

    OpenAIRE

    2013-01-01

    Study Type Retrospective review. Introduction Sagittal imbalance has been associated with lower health-related quality of life outcomes, and restoration of imbalance is associated with improved outcomes.1 2 3 The long constructs used in adult spinal deformity have potential consequences such as proximal junctional kyphosis (PJK). Clinically, the development of PJK may not be as important as failure of the construct or vertebrae at the proximal end. As PJK does not lead to worse clinical outco...

  13. A Solar Coronal Jet Event Triggers A Coronal Mass Ejection

    CERN Document Server

    Liu, Jiajia; Shen, Chenglong; Liu, Kai; Pan, Zonghao; Wang, S

    2015-01-01

    We present the multi-point and multi-wavelength observation and analysis on a solar coronal jet and coronal mass ejection (CME) event in this paper. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it propagate in a high speed over 1000 km/s . The jet erupted before and shared the same source region with the CME. The temporal and spacial relation- ship between them guide us the possibility that the jet triggered the CME and became its core. This scenario could promisingly enrich our understanding on the triggering mechanism of coronal mass ejections and their relations with coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the SDO/HMI instrument and the off- limb inverse Y-shaped configuration observed by SDO/AIA 171 A passband, together provide the first detailed observation on the three-dimensional reconnection process of large-scale jets as simulated in Pariat et al. 2009. ...

  14. Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection?

    Science.gov (United States)

    Attrill, Gemma D. R.; Harra, Louise K.; van Driel-Gesztelyi, Lidia; Démoulin, Pascal

    2007-02-01

    We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompanying the expansion of the EIT wave. We also report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions and simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behavior is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME magnetic field and quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings and the widespread diffuse dimming are identified as innate characteristics of this process.

  15. Sagittal Balance in Adolescent Idiopathic Scoliosis: A Radiographic Study of Spinopelvic Compensation After Selective Posterior Fusion of Thoracolumbar/Lumbar (Lenke 5C) Curves.

    Science.gov (United States)

    Xu, Xi-Ming; Wang, Fei; Zhou, Xiao-Yi; Liu, Zi-Xuan; Wei, Xian-Zhao; Bai, Yu-Shu; Li, Ming

    2015-11-01

    The relationship between spinal sagittal alignment and pelvic parameters is well known in adolescent idiopathic scoliosis. However, few studies have reported the sagittal spinopelvic relationship after selective posterior fusion of thoracolumbar/lumbar (TL/L) curves. We evaluated the relationship between spinal sagittal alignment and the pelvis, and analyzed how the pelvic sagittal state is adjusted in Lenke type 5C patients. We conducted a retrospective study of 36 patients with Lenke type 5C curves who received selective posterior TL/L curve fusion. Coronal and spinopelvic sagittal parameters were pre and postoperatively compared. Pearson coefficients were used to analyze the correlation between all spinopelvic sagittal parameters before and after surgery. We also evaluated 3 pelvic morphologies (anteverted, normal, and retroverted) before and after surgery. Preoperatively, the mean pelvic incidence was 46.0°, with a pelvic tilt and sacral slope (SS) of 8.2° and 37.8°, respectively, and 25% (9/36) of patients had an anteverted pelvis, whereas the other 75% had a normal pelvis. Postoperatively, 42% (15/36) of patients had a retroverted pelvis, 53% (19/36) had a normal pelvis, and 2 patients had an anteverted pelvis. Logistic regression analyses yielded 2 factors that were significantly associated with the risk for a postoperative unrecovered anteverted pelvis, including increased lumbar lordosis (LL) (odds ratio [OR] 4.8, P = 0.029) and increased SS (OR 5.6, P = 0.018). Four factors were significantly associated with the risk of a postoperative newly anteverted pelvis, including LL at the final follow-up (OR 6.9, P = 0.009), increased LL (OR 8.9, P = 0.003), LL below fusion (OR 9.4, P = 0.002), and increased SS (OR 11.5, P = 0.001). The pelvic state may be adjusted after selective posterior TL/L curve fusion in Lenke 5C adolescent idiopathic scoliosis patients. It is difficult to improve an anteverted pelvis in patients who have an LL

  16. Sagittal alignment of the spine: What do you need to know?

    Science.gov (United States)

    Diebo, Bassel G; Varghese, Jeffrey J; Lafage, Renaud; Schwab, Frank J; Lafage, Virginie

    2015-12-01

    Sagittal alignment, often misrepresented as sagittal balance, describes the ideal and "normal" alignment in the sagittal plane, resulting from the interplay between various organic factors. Any pathology that alters this equilibrium instigates sagittal malalignment and its compensatory mechanisms. As a result, sagittal malalignment is not limited to adult spinal deformity; its pervasiveness extends through most spinal disorders. While further research is developing, the literature reports clinically relevant radiographic parameters that have significant relationships with patient-reported outcomes. This article aims to provide a pragmatic review of sagittal plane analysis. At the end of this review, the reader should be able to analyze the sagittal plane of the spine, identify compensatory mechanisms, and choose patient-specific alignment targets.

  17. Exploring Coronal Structures with SOHO

    Indian Academy of Sciences (India)

    Μ. Karovska; Β. Wood; J. Chen; J. Cook; R. Howard

    2000-09-01

    We applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

  18. Non-inductive current driven by Alfvén waves in solar coronal loops

    Science.gov (United States)

    Elfimov, A. G.; de Azevedo, C. A.; de Assis, A. S.

    1996-08-01

    It has been shown that Alfvén waves can drive non-inductive current in solar coronal loops via collisional or collisionless damping. Assuming that all the coronal-loop density of dissipated wave power (W= 10-3 erg cm-3 s-1), which is necessary to keep the plasma hot, is due to Alfvén wave electron heating, we have estimated the axial current density driven by Alfvén waves to be ≈ 103 105 statA cm-2. This current can indeed support the quasi-stationary equilibrium and stability of coronal loops and create the poloidal magnetic field up to B θ≈1-5 G.

  19. Observational Signatures of Coronal Loop Heating and Cooling Driven by Footpoint Shuffling

    CERN Document Server

    Dahlburg, R B; Taylor, B D; Ugarte-Urra, I; Warren, H P; Rappazzo, A F; Velli, M

    2016-01-01

    The evolution of a coronal loop is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. The footpoints of the loop magnetic field are advected by random motions. As a consequence the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is non-uniformly distributed so that only a fraction of the coronal mass and volume gets heated at any time. Temperature and density are highly structured at scales which, in the solar corona, remain observationally unresolved: the plasma of our simulated loop is multi-thermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Numerical simulations of coronal loops of 50000 km length and axial magnetic field intensities ranging from 0.01...

  20. Direct coronal computed tomography of the lumbar spine: A new technical approach in supine position

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, P.; Uske, A.; Mansouri, B.

    1986-11-01

    Computed tomography (CT) was carried out on 46 subjects with L5-S1 disk hernia. All the patients had a L5-S1 angle equal or greater than 40 degrees. Coronal sections of the disk were obtained with a rostral angulation of the gantry, having placed the lumbar spin in a hyperlordotic position. Results are discussed and compared with those obtained from para-axial transverse sections and multidirectional reformated images.

  1. Mandibular nerve schwannoma resection using sagittal split ramus osteotomy.

    Science.gov (United States)

    Mahmood, Laith; Demian, Nagi; Weinstock, Yitzchak E; Weissferdt, Annikka

    2013-11-01

    A case is presented of a unique presentation and treatment of a mandibular nerve schwannoma. Its uniqueness stems from the fact that it consisted of 2 distinct tumors along the same nerve: one within the body of the mandible and the other within the ipsilateral pterygomandibular space. Rather than the standard approach of lip split and hemimandibulectomy, a unique approach of a sagittal split ramus osteotomy was used that allowed access to the 2 lesions and avoided the added morbidity of the former approach. The 2 portions of the lesion were successfully removed and the patient was satisfied with the result. Recurrence has not been detected after 6 months.

  2. Rondeau Seminars amalgamated mid-sagittal (lateral) cephalometric analysis.

    Science.gov (United States)

    Palencar, Adrian J

    2014-01-01

    The author presents a comprehensive International Association for Orthodontics--Rondeau Seminars Amalgamated Mid-sagittal (Lateral) Cephalometric Analysis. Norms on the Cephalometric Data Sheet are age and gender specific for the Caucasian population and the postings are color coded for visual attraction. If the patient is ofa different ethnic group, the Norms should be adjusted accordingly. This Cephalometric Analysis is comprised often Sections, in alphabetical order and twenty nine Factors. The author expanded Rondeau Seminars Cephalometric Analysis by only six Factors, thus fulfilling the requirement for the case presentation for the Fellow of the IAO and the Diplomate ofthe IBO.

  3. [Sagittal balance of the spine: a therapeutic revolution].

    Science.gov (United States)

    Faundez, A; Roussouly, P; Le Huec, J C

    2011-12-21

    In humans, the erect position and bipedal walk is possible because of a balance between pelvic and spinal parameters. The most important pelvic parameter is the pelvic incidence which represents the base on which the spine lies. With aging, thoracic kyphosis increases, lumbar lordosis decreases, compromising the spino-pelvic balance. Compensatory phenomenons are possible, but rely mostly on the amplitude of pelvic incidence. Analysis of spino-pelvic parameters and detection of a compensated or uncompensated sagittal imbalance are mandatory before any therapeutic action is undertaken for a degenerative pathology of the spine.

  4. Catastrophe of coronal magnetic flux ropes in fully open magnetic field

    Institute of Scientific and Technical Information of China (English)

    LI; Guoqiang(李国强); HU; Youqiu(胡友秋)

    2002-01-01

    The catastrophe of coronal magnetic flux ropes is closely related to solar explosive phenomena, such as prominence eruptions, coronal mass ejections, and two-ribbon solar flares. Using a 2-dimensional, 3-component ideal MHD model in Cartesian coordinates, numerical simulations are carried out to investigate the equilibrium property of a coronal magnetic flux rope which is embedded in a fully open background magnetic field. The flux rope emerges from the photosphere and enters the corona with its axial and annular magnetic fluxes controlled by a single "emergence parameter". For a flux rope that has entered the corona, we may change its axial and annular fluxes artificially and let the whole system reach a new equilibrium through numerical simulations. The results obtained show that when the emergence parameter, the axial flux, or the annular flux is smaller than a certain critical value, the flux rope is in equilibrium and adheres to the photosphere. On the other hand, if the critical value is exceeded, the flux rope loses equilibrium and erupts freely upward, namely, a catastrophe takes place. In contrast with the partly-opened background field, the catastrophic amplitude is infinite for the case of fully-opened background field.

  5. [Sagittal Balance of the Spine--Clinical Importance and Radiographic Assessment].

    Science.gov (United States)

    Decker, S; Müller, C W; Omar, M; Krettek, C; Schwab, F; Trobisch, P D

    2016-04-01

    Sagittal deformities of the spine frequently result in back pain, as patients have to expend much energy in compensation. The sagittal alignment of the spine is defined by its curvatures (lordosis and kyphosis) relative to the position of the pelvis. Diagnostic assessment is based on full spine a. p. and lateral X-rays. The sagittal balance is primarily described by different angles that can be measured, e.g. lumbar lordosis, pelvic incidence, pelvic tilt and thoracic kyphosis. The quality of life can best be estimated by subtracting lumbar lordosis from the pelvic incidence. However, initial evaluation of the sagittal balance can also be based on the sagittal vertical axis. The severity of imbalance can be described by the sagittal vertical axis and the pelvic tilt, but surgical therapy necessitates a more profound analysis, which can be based on the SRS-Schwab classification.

  6. Intrinsic Instability of Coronal Streamers

    CERN Document Server

    Chen, Y; Song, H Q; Shi, Q Q; Feng, S W; Xia, L D; 10.1088/0004-637X/691/2/1936

    2009-01-01

    Plasma blobs are observed to be weak density enhancements as radially stretched structures emerging from the cusps of quiescent coronal streamers. In this paper, it is suggested that the formation of blobs is a consequence of an intrinsic instability of coronal streamers occurring at a very localized region around the cusp. The evolutionary process of the instability, as revealed in our calculations, can be described as follows: (1) through the localized cusp region where the field is too weak to sustain the confinement, plasmas expand and stretch the closed field lines radially outward as a result of the freezing-in effect of plasma-magnetic field coupling; the expansion brings a strong velocity gradient into the slow wind regime providing the free energy necessary for the onset of a subsequent magnetohydrodynamic instability; (2) the instability manifests itself mainly as mixed streaming sausage-kink modes, the former results in pinches of elongated magnetic loops to provoke reconnections at one or many loc...

  7. Correlates of Bone Mineral Density and Sagittal Spinal Balance in the Aged

    OpenAIRE

    2015-01-01

    Objective To investigate the relationship between bone mineral density (BMD) and sagittal spinal balance in the Korean elderly population. Methods The retrospective study included subjects aged 60 years and above, who had whole-spine lateral radiography and dual-energy X-ray absorptiometry (DEXA) within a year's gap between each other. Sagittal vertical axis (SVA) for evaluation of sagittal spinal balance and five spinopelvic parameters were measured through radiography. The presence of compr...

  8. Motion Magnification in Coronal Seismology

    Science.gov (United States)

    Anfinogentov, Sergey; Nakariakov, Valery M.

    2016-11-01

    We introduce a new method for the investigation of low-amplitude transverse oscillations of solar plasma non-uniformities, such as coronal loops, individual strands in coronal arcades, jets, prominence fibrils, polar plumes, and other contrast features that have been observed with imaging instruments. The method is based on the two-dimensional dual-tree complex wavelet transform (DTℂWT). It allows us to magnify transverse, in the plane-of-the-sky, quasi-periodic motions of contrast features in image sequences. The tests performed on the artificial data cubes that imitated exponentially decaying, multi-periodic and frequency-modulated kink oscillations of coronal loops showed the effectiveness, reliability, and robustness of this technique. The algorithm was found to give linear scaling of the magnified amplitudes with the original amplitudes, provided these are sufficiently small. In addition, the magnification is independent of the oscillation period in a broad range of the periods. The application of this technique to SDO/AIA EUV data cubes of a non-flaring active region allowed for the improved detection of low-amplitude decay-less oscillations in the majority of loops.

  9. Mid-sagittal plane and mid-sagittal surface optimization in brain MRI using a local symmetry measure

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Skoglund, Karl; Ryberg, Charlotte

    2005-01-01

    years). Traditionally, the mid-sagittal plane is localized by global measures. However, this approach fails when the partitioning plane between the brain hemispheres does not coincide with the symmetry plane of the head. We instead propose to use a sparse set of profiles in the plane normal direction...... and maximize the local symmetry around these using a general-purpose optimizer. The plane is parameterized by azimuth and elevation angles along with the distance to the origin in the normal direction. This approach leads to solutions confirmed as the optimal MSP in 98 percent of the subjects. Despite the name...

  10. Altered Axial Skeletal Development

    Science.gov (United States)

    The axial skeleton is routinely examined in standard developmental toxicity bioassays and has proven to be sensitive to a wide variety of chemical agents. Dysmorphogenesis in the skull, vertebral column and ribs has been described in both human populations and in laboratory anima...

  11. Microsurgical Treatment of Meningiomas Invading the Sagittal or Transverse Sinuses

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    OBJECTIVE To analyze our management strategy and results of treating patients affected by meningiomas invading the sagittalor transverse sinuses.METHODS Review of data from 35 patients with pathologically confirmed meningiomas(29 of the sagittal sinus and 6 of the transverse sinus)surgically treated between from July 1999 and June 2003, including clinical manifestations, mode of diagnosis and curative effect of microsurgery etc.For our surgical decision-making, meningiomas were classified into six types based on the degree of sinus involvement.RESULTS A Simpson's Grade I resection was achieved in 27 cases (77.1%), Grade Ⅱ in 6 (17.1%) and Grade Ⅲ in 2 (5.7%). No patients died after the operations. The recurrence rate in the study overall was 2.9%, with a follow-up period from 3 to 6 years.CONCLUSION Application of microsurgical techniques, protection of the sinus, avoidance of damages to the cerebral cortex, veins of the central sulcus, as well as other veins from the tumor, are the major factors for increasing the rate of total resection, reducing complications and improving the quality of life for the patients with meningiomas invading the sagittal or transverse sinuses.

  12. Distribution of sagittal occlusal relationships in different stages of dentition

    Directory of Open Access Journals (Sweden)

    Emine KAYGISIZ

    2015-01-01

    Full Text Available The aim of this study was to assess the distribution of sagittal occlusal relationships in different dentition periods in a Turkish sample group. In total, 1,110 patients (561 females, 549 males aged 4.6-23 years were randomly chosen after intraoral clinical examination. The subjects were classified according to their sagittal occlusal relationships and four dentition stages –deciduous, early mixed, late mixed, and permanent dentition. The statistical significance of the occurrence of malocclusion types in dentition stages was evaluated by Chi-square and Fischer’s exact tests. Class I malocclusion was observed at the highest rate in all dentition stages. Class III malocclusion was observed at the highest rate in the permanent dentition, whereas Class II malocclusion was observed at the highest rate in the late mixed dentition. The rates of Class I, II, and III malocclusions were similar in males and females. Our study reveals that the prevalence of malocclusion and need for orthodontic treatment has increased in the population towards the permanent dentition.

  13. Analysis of sagittal condyl inclination in subjects with temporomandibular disorders

    Directory of Open Access Journals (Sweden)

    Dodić Slobodan

    2010-01-01

    Full Text Available Bacground/Aim. Disturbances of mandibular border movements is considered to be one of the major signs of temporomandibular disorders (TMD. The purpose of this study was to evaluate the possible association between disturbances of mandibular border movements and the presence of symptoms of TMD in the young. Methods. This study included two groups of volunteers between 18 and 26 years of age. The study group included 30 examineers with signs (symptoms of TMD, and the control group also included 30 persons without any signs (symptoms of TMD. The presence of TMD was confirmed according to the craniomandibular index (Helkimo. The functional analysis of mandibular movements was performed in each subject using the computer pantograph. Results. The results of this study did not confirm any significant differences between the values of the condylar variables/sagittal condylar inclination, length of the sagital condylar guidance, in the control and in the study group. Conclusion. The study did not confirm significant differences in the length and inclination of the protrusive condylar guidance, as well as in the values of the sagittal condylar inclination between the subjects with the signs and symptoms of TMD and the normal asymptomatic subjects.

  14. [Inadvertent thoracic duct puncture during right axially central venous cannulation].

    Science.gov (United States)

    Kawashima, Shingo; Itagaki, Taiga; Adachi, Yushi; Ishii, Yasuhiro; Taniguchi, Midzuki; Doi, Matsuyuki; Sato, Shigehito

    2010-10-01

    A case of inadvertent thoracic duct puncture during right axially central venous cannulation is reported. The catheterization was performed under the real time ultrasound guidance technique and the coronal view image was continuously displayed. After confirming the feelings of venous puncture, clear yellow fluid was aspired into the connected syringe to the needle. Initially, an accidental thoracic puncture with subsequent pleural fluid aspiration was suspected;however, no finding of pleural effusion was observed with ultrasound imaging and computed tomography. Thus, an accidental thoracic duct puncture and the subsequent lymph fluid aspiration were suspected. Even in a right side approach for central venous catheterization, thoracic duct injury might ensure.

  15. Subjective and objective image qualities: a comparison of sagittal T2 weighted spin-echo and turbo-spin-eco sequences in magnetic resonance imaging of the spine by use of a subjective ranking system

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, G. [Institut fuer diagnostische Radiologie, Departement Radiologie, Universitaetskliniken, Kantonsspital Basel (Switzerland); Mader, I. [Radiologische Gemeinschaftspraxis Dres. Siems, Grossmann, Bayreuth (Germany); Proske, M. [Klinikum Rosenheim (Germany). Inst. fuer Diagnostische Radiologie

    1998-12-31

    We evaluated the subjective image impression of two different magnetic resonance (MR) sequences by using a subjective ranking system. This ranking system was based on 20 criteria describing several tissue characteristics such as the signal intensity of normal anatomical structures and the changes of signal intensities and shape of lesions as well as artefacts. MR of the vertebral spine was performed in 48 female and 52 male patients (mean age 44.8 years) referred consecutively for investigation of a back problem. Ninety-six pathologies were found in 82 patients. Sagittal and axial T1 weighted spin-echo before and after administration of Gadolinium (Gd-DOTA), and sagittal T2 weighted spin-echo (T2wSE) and Turbo-spin-echo (TSE) sequences were performed by means of surface coils. Using the subjective ranking system the sagittal T2wSE and sagittal TSE were compared. Both sequences were suitable for identification of normal anatomy and pathologic changes and there was no trend for increased detection of disease by one imaging sequence over the other. We found that sagittal TSE sequences can replace sagittal T2wSE sequences in spinal MR and that artefacts at the cervical and lumbar spine are less frequent using TSE, thus confirming previous studies. In this study, our ranking system reveiled, that there are differences between the subjective judgement of image qualities and objective measurement of SNR. However, this approach may not be helpful to compare two different MR sequences as it is limited to the anatomical area investigated and is time consuming. The subjective image impression, i.e. the quality of images, may not always be represented by physical parameters such as a signal-to-noise ratio (SNR), radiologists should try to define influences of image quality also by subjective parameters. (orig.)

  16. A SOLAR CORONAL JET EVENT TRIGGERS A CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiajia; Wang, Yuming; Shen, Chenglong; Liu, Kai; Pan, Zonghao; Wang, S. [CAS Key Laboratory of Geospace Environment, Earh and Space Science School, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026 (China)

    2015-11-10

    In this paper, we present multi-point, multi-wavelength observations and analysis of a solar coronal jet and coronal mass ejection (CME) event. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it to propagate at a high speed of over 1000 km s{sup −1}. The jet erupted before the CME and shared the same source region. The temporal and spacial relationship between these two events lead us to the possibility that the jet triggered the CME and became its core. This scenario hold the promise of enriching our understanding of the triggering mechanism of CMEs and their relations to coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the Solar Dynamics Observatory (SDO)/HMI instrument along with the off-limb inverse Y-shaped configuration observed by SDO/AIA in the 171 Å passband provide the first detailed observation of the three-dimensional reconnection process of a large-scale jet as simulated in Pariat et al. The eruption process of the jet highlights the importance of filament-like material during the eruption of not only small-scale X-ray jets, but likely also of large-scale EUV jets. Based on our observations and analysis, we propose the most probable mechanism for the whole event, with a blob structure overlaying the three-dimensional structure of the jet, to describe the interaction between the jet and the CME.

  17. The influence of elastic orthotic belt on sagittal profile in adolescent idiopathic thoracic scoliosis: a comparative radiographic study with Milwaukee brace

    Directory of Open Access Journals (Sweden)

    Qian Bangping

    2010-09-01

    Full Text Available Abstract Background The effectiveness of bracing on preventing curve progression in coronal plane for mild and moderate adolescent idiopathic scoliosis (AIS patients has been confirmed by previous radiographic researches. However, a hypokyphotic effect on the sagittal plane has been reported by a few studies. A relatively increasing number of AIS patients were noticed to wear a new kind of elastic orthotic belt for the treatments of scoliosis without doctors' instructions. We postulate the correcting mechanism of this new appliance may cause flattening of the spine. To our knowledge, no study has investigated the effects of this new orthosis on the sagittal profile of AIS patients. The aim of this study was to evaluate and compare the effects of elastic orthotic belt and Milwaukee brace on the sagittal alignment in AIS patients. Methods Twenty-eight female AIS patients with mild or moderate thoracic curves were included in this study. Standing full-length lateral radiographs were obtained in three conditions: natural standing posture without any treatment, with elastic orthotic belt and with Milwaukee brace. Thoracic kyphosis (TK, lumber lordosis (LL and pelvic incidence (PI were measured and compared between the above three conditions. Results Both elastic orthotic belt and Milwaukee brace can lead to significant decrease of TK, however, the decrease of TK after wearing elastic orthotic belt is significantly larger than that after wearing Milwaukee brace. Compared with no treatment, LL was found to be significantly smaller after wearing Milwaukee brace, however, such significant decrease was not noted after wearing elastic orthotic belt. No significant changes were observed for the PI between 3 conditions. Conclusions The elastic orthotic belt could lead to more severe thoracic hypokyphosis when compared with Milwaukee brace. This belt may not be a suitable conservative method for the treatment of mild and moderate AIS patients.

  18. From Forbidden Coronal Lines to Meaningful Coronal Magnetic Fields

    CERN Document Server

    Judge, Philip G; Landi, Enrico

    2013-01-01

    We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of magnetic free energy within coronal plasmas. We address commonly held skepticisms concerning angular ambiguities and line-of-sight confusion. We argue that ambiguities are in principle no worse than more familiar remotely sensed photospheric vector-fields, and that the diagnosis of M1 line data would benefit from simultaneous observations of EUV lines. Based on calculations and data from eclipses, we discuss the most promising lines and different approaches that might be used. We point to the S-like [Fe {\\sc XI}] line (J=2 to J=1) at 789.2nm as a prime target line (for ATST for example) to augment the hotter 1074.7 and 1079.8 nm Si-like lines of [Fe {\\sc XIII}] currently observed by the Coronal Multi-channel Polarimeter (CoMP). Significant breakthroughs will be made possibl...

  19. Sagittal spinopelvic parameters in 2-level lumbar degenerative spondylolisthesis

    Science.gov (United States)

    Wang, Tao; Wang, Hui; Liu, Huan; Ma, Lei; Liu, Feng-Yu; Ding, Wen-Yuan

    2016-01-01

    Abstract The purpose of our study is to evaluate sagittal parameters in 2-level lumbar degenerative spondylolisthesis (DS) (TLDS). A total of 15 patients with TLDS, 40 patients with single-level DS (SLDS), and 30 normal volunteers as control were included in our study. All subjects performed on full spine X-ray. Two categorized data were analyzed: patient characteristics—age, sex, body mass index, radiographic parameters-pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), sacral slope (SS), PI–LL, Cobb between the fifth thoracic vertebral and 12th thoracic vertebral (T5–T12), sagittal vertical axis (SVA) Cobb angle of spondylolisthesis level (CSL), ratio of PT to SS (PT/SS), CSL/LL, variation trend of SS over PI, and LL over PI. The PI (73.1° vs 52.9°), SS (50.8° vs 32.2°), LL (53.1° vs 46.9°), SVA (66.1 vs 22.0 mm), PI–LL (20.0° vs 6.0°), and CSL (23.6° vs 20.0°) in TLDS were significantly larger than these in SLDS. The PI (73.1° vs 40.6°), PT (22.3° vs 17.1°), SS (50.8° vs 23.5°), LL (53.1° vs 32.5°), PI–LL (20.0° vs 8.1°), and SVA (66.1 vs 17.0 mm) in TLDS were significantly larger than those in the normal group (NG). The PI (52.9° vs 40.6°), PT (21.0° vs 17.1°), SS (32.2° vs 23.5°), LL (46.9° vs 32.5°), and SVA (22.0 vs 17.0 mm) in SLDS were significantly higher than those in NG. However, PT/SS (44.0%), LL over PI (y = 0.39x + 24.25), SS over PI (y = 10.79 + 0.55x) were lower in TLDS than these in SLDS (63.8%, y = 0.41x + 25, y = 0.65x − 2.09, respectively), and the similar tend between SLDS and NG (74.0%, y = 0.49x + 13.09, y = 0.67x − 3.9, respectively). Our results showed that 2-level lumbar DS, which was caused by multiple-factors, has a severe sagittal imbalance, but single-level has not any. When we plan for surgical selection for 2-level lumbar DS, global sagittal balance must be considered. PMID:27977581

  20. Sagittal laser optical tomography for imaging of rheumatoid finger joints

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, Andreas H [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Klose, Alexander D [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Scheel, Alexander K [Department of Nephrology and Rheumatology, Georg-August University, Goettingen (Germany); Moa-Anderson, Bryte [Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027 (United States); Backhaus, Marina [Department of Rheumatology and Clinical Immunology, Charite University Hospital, Berlin (Germany); Netz, Uwe [Institute for Medical Physics and Laser Medicine, Free University of Berlin, Berlin (Germany); Beuthan, Juergen [Institute for Medical Physics and Laser Medicine, Free University of Berlin, Berlin (Germany)

    2004-04-07

    We present a novel optical tomographic imaging system that was designed to determine two-dimensional spatial distribution of optical properties in a sagittal plane through finger joints. The system incorporates a single laser diode and a single silicon photodetector into a scanning device that records spatially resolved light intensities as they are transmitted through a finger. These data are input to a model-based iterative image reconstruction (MOBIIR) scheme, which uses the equation of radiative transfer (ERT) as a forward model for light propagation through tissue. We have used this system to obtain tomographic images of six proximal interphalangeal finger joints from two patients with rheumatoid arthritis. The optical images were compared to clinical symptoms and ultrasound images.

  1. Removal of Deeply Impacted Mandibular Molars by Sagittal Split Osteotomy

    Directory of Open Access Journals (Sweden)

    Erol Cansiz

    2016-01-01

    Full Text Available Mandibular third molars are the most common impacted teeth. Mandibular first and second molars do not share the same frequency of occurrence. In rare cases the occlusal surfaces of impacted molars are united by the same follicular space and the roots pointing in opposite direction; these are called kissing molars. In some cases, a supernumerary fourth molar can be seen as unerupted and, in this case, such a supernumerary, deeply impacted fourth molar is seen neighboring kissing molars. The extraction of deeply impacted wisdom molars from the mandible may necessitate excessive bone removal and it causes complications such as damage to the inferior alveolar nerve and iatrogenic fractures of the mandible. This case report describes the use of the sagittal split osteotomy technique to avoid extensive bone removal and protect the inferior alveolar nerve during surgical extruction of multiple impacted teeth.

  2. Superior Sagittal Sinus Thrombosis Complicating Typhoid Fever in a Teenager

    Directory of Open Access Journals (Sweden)

    P. O. Okunola

    2012-01-01

    Full Text Available Cerebral venous sinus (sinovenous thrombosis (CSVT is a rare life-threatening disorder in childhood that is often misdiagnosed. CSVT encompasses cavernous sinus thrombosis, lateral sinus thrombosis, and superior sagittal sinus thrombosis (SSST. We present an adolescent girl who was well until two weeks earlier when she had a throbbing frontal headache and fever with chills; she later had dyspnoea, jaundice, melena stool, multiple seizures, nuchal rigidity, and monoparesis of the right lower limb a day before admission. Urine test for Salmonella typhi Vi antigen was positive, and Widal reaction was significant. Serial cranial computerized tomography scans revealed an expanding hypodense lesion in the parafalcine region consistent with SSST or a parasagittal abscess. Inadvertent left parietal limited craniectomy confirmed SSST. She recovered completely with subsequent conservative management. Beyond neuropsychiatric complications of Typhoid fever, CSVT should be highly considered when focal neurologic deficits are present.

  3. Subtotal cranial vault remodelling in anterior sagittal suture closure: impact of age on surgical outcome

    NARCIS (Netherlands)

    Engel, M.; Hoffmann, J.; Muhling, J.; Castrillon-Oberndorfer, G.; Seeberger, R.; Freudlsperger, C.

    2012-01-01

    Isolated fusion of the sagittal suture is usually treated before 1 year of age, but some patients present at a later age. The aim of this study was to evaluate the impact of children's age on the surgical outcome. The authors investigated 46 patients with isolated nonsyndromic sagittal craniosynosto

  4. Extensor Tendon Instability Due to Sagittal Band Injury in a Martial Arts Athlete: A Case Report.

    Science.gov (United States)

    Kochevar, Andrew; Rayan, Ghazi

    2017-03-01

    A Taekwondo participant sustained a hand injury from punching an opponent that resulted in painful instability of the ring finger extensor digitorum communis tendon due to sagittal band damage. His symptoms resolved after reconstructive surgery on the sagittal band (SB) with stabilization of the extensor tendon over the metacarpophalangeal joint.

  5. Sagittal balance and pelvic parameters--a paradigm shift in spinal surgery.

    Science.gov (United States)

    Johnson, R D; Valore, A; Villaminar, A; Comisso, M; Balsano, M

    2013-02-01

    It has become evident in recent years that global assessment of spinal sagittal balance is necessary for optimal management of the degenerate spine. Pelvic parameters have been developed which appear to correlate well with the natural history of degenerative spine disorders and outcomes from surgery. Although these parameters have a limited evidence base, they are now in widespread use by spinal surgeons and, in particular, spinal deformity surgeons. It is necessary for all surgeons treating spinal pathology to have a working knowledge of the principles of spinal sagittal balance, to be able to recognise sagittal imbalance and its compensatory mechanisms. In this article we outline the main concepts of spinal sagittal balance and pelvic parameters and how these concepts are leading to a paradigm shift in the surgical management of spinal disorders. We propose that analysis of pelvic parameters of sagittal balance will form an essential part of the evaluation of new surgical techniques for spinal conditions.

  6. Deep coronal hole associated with quiescent filament

    Science.gov (United States)

    Kesumaningrum, Rasdewita; Herdiwidjaya, Dhani

    2014-03-01

    We present a study of the morphology of quiescent filament observed by H-alpha Solar Telescope at Bosscha Observatory in association with coronal hole observed by Atmospheric Imaging Assembly (AIA) instrument in 193 Å from Solar Dynamics Observatory. H-alpha images were processed by imaging softwares, namely Iris 5.59 and ImageJ, to enhance the signal to noise ratio and to identify the filament features associated with coronal hole. For images observed on October 12, 2011, November 14, 2011 and January 2, 2012, we identified distinct features of coronal holes above the quiescent filaments. This associated coronal holes have filament-like morphology with a thick long thread as it's `spine', defined as Deep Coronal Hole. Because of strong magnetic field of sunspot, these filaments and coronal holes emerged far from active region and lasted for several days. It is interesting as for segmented filament, deep coronal holes above the filaments lasted for a quite long period of time and merged. This association between filament and deep coronal hole can be explained by filament magnetic loop.

  7. Pre-flare coronal dimmings

    CERN Document Server

    Zhang, Q M; Ji, H S

    2016-01-01

    In this paper, we focus on the pre-flare coronal dimmings. We report our multiwavelength observations of the GOES X1.6 solar flare and the accompanying halo CME produced by the eruption of a sigmoidal magnetic flux rope (MFR) in NOAA active region (AR) 12158 on 2014 September 10. The eruption was observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory (SDO). The photospheric line-of-sight magnetograms were observed by the Helioseismic and Magnetic Imager (HMI) aboard SDO. The soft X-ray (SXR) fluxes were recorded by the GOES spacecraft. The halo CME was observed by the white light coronagraphs of the Large Angle Spectroscopic Coronagraph (LASCO) aboard SOHO.} {About 96 minutes before the onset of flare/CME, narrow pre-flare coronal dimmings appeared at the two ends of the twisted MFR. They extended very slowly with their intensities decreasing with time, while their apparent widths (8$-$9 Mm) nearly kept constant. During the impulsive and decay phases of flare, typical fanlike ...

  8. Magnetic shuffling of coronal downdrafts

    Science.gov (United States)

    Petralia, A.; Reale, F.; Orlando, S.

    2017-02-01

    Context. Channelled fragmented downflows are ubiquitous in magnetized atmospheres, and have recently been addressed based on an observation after a solar eruption. Aims: We study the possible back-effect of the magnetic field on the propagation of confined flows. Methods: We compared two 3D magnetohydrodynamic simulations of dense supersonic plasma blobs that fall down along a coronal magnetic flux tube. In one, the blobs move strictly along the field lines; in the other, the initial velocity of the blobs is not perfectly aligned with the magnetic field and the field is weaker. Results: The aligned blobs remain compact while flowing along the tube, with the generated shocks. The misaligned blobs are disrupted and merge through the chaotic shuffling of the field lines. They are structured into thinner filaments. Alfvén wave fronts are generated together with shocks ahead of the dense moving front. Conclusions: Downflowing plasma fragments can be chaotically and efficiently mixed if their motion is misaligned with field lines, with broad implications for disk accretion in protostars, coronal eruptions, and rain, for example. Movies associated to Figs. 2 and 3 are available at http://www.aanda.org

  9. EIT waves and coronal magnetic field diagnostics

    Institute of Scientific and Technical Information of China (English)

    CHEN PengFei

    2009-01-01

    Magnetic field in the solar lower atmosphere can be measured by the use of the Zeeman and Hanle effects. By contrast, the coronal magnetic field well above the solar surface, which directly controls various eruptive phenomena, can not be precisely measured with the traditional techniques. Several attempts are being made to probe the coronal magnetic field, such as force-free extrapolation based on the photospheric magnetograms, gyroresonance radio emissions, and coronal seismology based on MHD waves in the corona. Compared to the waves trapped in the localized coronal loops, EIT waves are the only global-scale wave phenomenon, and thus are the ideal tool for the coronal global seismology. In this paper, we review the observations and modelings of EIT waves, and illustrate how they can be applied to probe the global magnetic field in the corona.

  10. The Inconvenient Truth About Coronal Dimmings

    CERN Document Server

    McIntosh, Scott W

    2008-01-01

    We investigate the occurrence of a coronal dimming using a combination of high resolution spectro-polarimetric, spectral and broadband images which span from the deep photosphere into the corona. These observations reinforce the belief that coronal dimmings, or transient coronal holes as they are also known, are indeed the locations of open magnetic flux in the corona resulting from the launch of a CME. We will see that, as open magnetic regions, they must act just as coronal holes and be sources of the fast solar wind, but only temporarily. An inescapable question therefore arises - what impact does this source of fast wind have on the propagation and in-flight characteristics of the CME that initiates the coronal dimming in the first place?

  11. Blind Stereoscopy of the Coronal Magnetic Field

    CERN Document Server

    Aschwanden, Markus J; Malanushenko, Anna

    2015-01-01

    We test the feasibility of 3D coronal-loop tracing in stereoscopic EUV image pairs, with the ultimate goal of enabling efficient 3D reconstruction of the coronal magnetic field that drives flares and coronal mass ejections (CMEs). We developed an automated code designed to perform triangulation of coronal loops in pairs (or triplets) of EUV images recorded from different perspectives. The automated (or blind) stereoscopy code includes three major tasks: (i) automated pattern recognition of coronal loops in EUV images, (ii) automated pairing of corresponding loop patterns from two different aspect angles, and (iii) stereoscopic triangulation of 3D loop coordinates. We perform tests with simulated stereoscopic EUV images and quantify the accuracy of all three procedures. In addition we test the performance of the blind stereoscopy code as a function of the spacecraft-separation angle and as a function of the spatial resolution. We also test the sensitivity to magnetic non-potentiality. The automated code develo...

  12. Critical Axial Load

    Directory of Open Access Journals (Sweden)

    Walt Wells

    2008-01-01

    Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.

  13. Network Coronal Bright Points: Coronal Heating Concentrations Found in the Solar Magnetic Network

    Science.gov (United States)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Hathaway, D. H.

    1998-01-01

    We examine the magnetic origins of coronal heating in quiet regions by combining SOHO/EIT Fe xii coronal images and Kitt Peak magnetograms. Spatial filtering of the coronal images shows a network of enhanced structures on the scale of the magnetic network in quiet regions. Superposition of the filtered coronal images on maps of the magnetic network extracted from the magnetograms shows that the coronal network does indeed trace and stem from the magnetic network. Network coronal bright points, the brightest features in the network lanes, are found to have a highly significant coincidence with polarity dividing lines (neutral lines) in the network and are often at the feet of enhanced coronal structures that stem from the network and reach out over the cell interiors. These results indicate that, similar to the close linkage of neutral-line core fields with coronal heating in active regions (shown in previous work), low-lying core fields encasing neutral lines in the magnetic network often drive noticeable coronal heating both within themselves (the network coronal bright points) and on more extended field lines rooted around them. This behavior favors the possibility that active core fields in the network are the main drivers of the heating of the bulk of the quiet corona, on scales much larger than the network lanes and cells.

  14. Association between CYP19A1 genotype and pubertal sagittal jaw growth

    Science.gov (United States)

    He, Shushu; Hartsfield, James K.; Guo, Yujiao; Cao, Yang; Wang, Si; Chen, Song

    2016-01-01

    Introduction Sagittal jaw growth is influenced during puberty by a ratio of androgens and estrogens. The CYP19A1 (formerly CYP19) gene encodes the cytochrome P450 enzyme aromatase (estrogen synthetase), which converts testosterone to estrogen. Genetic variations including single nucleotide polymorphisms might regulate CYP19A1 gene expression or the function of the aromatase protein and thus influence sagittal jaw growth. Methods The annual sagittal jaw growth in 92 pubertal orthodontic patients was determined by using pretreatment and posttreatment cephalometric radiographs. Single nucleotide polymorphisms rs2470144 and rs2445761 were genotyped and haplotypes constructed. Associations between genotypes or haplotypes and the annual sagittal growth were estimated by using JMP (version 9.0; SAS Institute, Cary, NC). Results Two single nucleotide polymorphisms were significantly associated with average differences in annual sagittal jaw growth in boys. Haplotype analysis demonstrated that haplotypes Trs2470144Trs2445761 and Crs2470144Trs2445761 had significant effects on annual sagittal maxillary growth and on mandibular growth in boys. No association was found in girls. Conclusions A quantitative trait locus that influences male pubertal sagittal jaw growth might exist in the CYP19A1 gene, and single nucleotide polymorphisms rs2470144 and rs2445761 might be inside this quantitative trait locus or be linked to it. PMID:23116507

  15. SAGITTAL DIAMETER OF FORAMEN MAGNUM IN NORMAL POPULATION: AN MRI STUDY

    Directory of Open Access Journals (Sweden)

    Lakshmi

    2015-11-01

    Full Text Available Lower position of cerebellar tonsils was frequently noticed in Western studies. In some of the studies, sagittal diameter of foramen magnum was found to be larger in cases of Chiari malformation. However, there are no Indian studies for comparison. Our study was proposed to determine the standard values for sagittal diameter of foramen magnum in various age groups and both sexes. This gives a guideline for further studies in pathological conditions like Craniovertebral Junctional (CVJ anomalies, and Chiari malformation. The sagittal diameter of foramen magnum was measured in 515 patients during MRI investigation directly on the MR images on the MR monitor in mid sagittal sections of head and cervical spine. The patients underwent the MR investigation for various vague complaints at the Radiology Department of SCTIMST, Trivandrum. They were found to have normal brain and spinal cord. They ranged from 2 months to 80 years of age in both sexes. Established cases of CVJ anomalies and raised intracranial tension were excluded. The results showed a mean sagittal diameter of 35.57 ± 3.72 mm with a range of 15 to 45 mm. The sagittal diameter increased up to 15 years, then remained static thereafter. Females showed smaller diameter compared to males. ANOVA showed a high statistically significant P-value of 0.001 for males and 0.004 for females. The study resulted in standard values of sagittal diameter of foramen magnum for different age groups in both sexes.

  16. Recent advances in coronal heating

    CERN Document Server

    De Moortel, Ineke

    2015-01-01

    The solar corona, the tenuous outer atmosphere of the Sun, is orders of magnitude hotter than the solar surface. This 'coronal heating problem' requires the identification of a heat source to balance losses due to thermal conduction, radiation and (in some locations) convection. The review papers in this Theo Murphy meeting issue present an overview of recent observational findings, large- and small-scale numerical modelling of physical processes occurring in the solar atmosphere and other aspects which may affect our understanding of the proposed heating mechanisms. At the same time, they also set out the directions and challenges which must be tackled by future research. In this brief introduction, we summarize some of the issues and themes which reoccur throughout this issue.

  17. Observational features of equatorial coronal hole jets

    Directory of Open Access Journals (Sweden)

    G. Zimbardo

    2010-03-01

    Full Text Available Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km s−1, while the deceleration rate appears to be about 0.11 km s−2, less than solar gravity. The average jet visibility time is about 30 min, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and equatorial coronal hole jets.

  18. FORWARD: A toolset for multiwavelength coronal magnetometry

    Science.gov (United States)

    Gibson, Sarah; Kucera, Therese; White, Stephen; Dove, James; Fan, Yuhong; Forland, Blake; Rachmeler, Laurel; Downs, Cooper; Reeves, Katharine

    2016-03-01

    Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data.

  19. FORWARD: A toolset for multiwavelength coronal magnetometry

    Directory of Open Access Journals (Sweden)

    Sarah eGibson

    2016-03-01

    Full Text Available Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data.

  20. Space weather and coronal mass ejections

    CERN Document Server

    Howard, Tim

    2013-01-01

    Space weather has attracted a lot of attention in recent times. Severe space weather can disrupt spacecraft, and on Earth can be the cause of power outages and power station failure. It also presents a radiation hazard for airline passengers and astronauts. These ""magnetic storms"" are most commonly caused by coronal mass ejections, or CMES, which are large eruptions of plasma and magnetic field from the Sun that can reach speeds of several thousand km/s. In this SpringerBrief, Space Weather and Coronal Mass Ejections, author Timothy Howard briefly introduces the coronal mass ejection, its sc

  1. Slipping magnetic reconnection in coronal loops.

    Science.gov (United States)

    Aulanier, Guillaume; Golub, Leon; Deluca, Edward E; Cirtain, Jonathan W; Kano, Ryouhei; Lundquist, Loraine L; Narukage, Noriyuki; Sakao, Taro; Weber, Mark A

    2007-12-07

    Magnetic reconnection of solar coronal loops is the main process that causes solar flares and possibly coronal heating. In the standard model, magnetic field lines break and reconnect instantaneously at places where the field mapping is discontinuous. However, another mode may operate where the magnetic field mapping is continuous but shows steep gradients: The field lines may slip across each other. Soft x-ray observations of fast bidirectional motions of coronal loops, observed by the Hinode spacecraft, support the existence of this slipping magnetic reconnection regime in the Sun's corona. This basic process should be considered when interpreting reconnection, both on the Sun and in laboratory-based plasma experiments.

  2. Prediction of neurosensory alterations after sagittal split ramus osteotomy.

    Science.gov (United States)

    Kuroyanagi, N; Miyachi, H; Ochiai, S; Kamiya, N; Kanazawa, T; Nagao, T; Shimozato, K

    2013-07-01

    Prediction of neurosensory deficit in the lower lip and chin after sagittal split ramus osteotomy (SSRO) is challenging. This study aimed to elucidate factors related to the development and improvement of neurosensory disturbance (NSD) after SSRO with respect to surgical procedure and the anatomical and structural characteristics of the craniomaxillofacial skeleton. Subjects comprised 50 patients treated by a single experienced surgeon. Anatomical data and landmarks were obtained by computed tomography (CT) imaging. There was a significant difference between patients with or without NSD for the surgical space on the medial side of mandibular ramus 1 week after SSRO (P=0.006). Less than 15.0mm between the lingula and mandibular notch (relative risk, 6.7; 95% CI, 1.7-33.8) and 195.0mm(2) or more space on the medial side of the mandibular ramus (relative risk, 17.2; 95% CI, 3.9-100.4) indicated a significant risk of NSD development at 6 months postoperatively. These results suggested that the development of NSD is related to the surgical space on the medial side of the mandibular ramus and subsequent manipulation of the inferior alveolar nerve (IAN) in that region. Limited periosteal degloving prevents excessive stretching of the IAN during SSRO, thus lowering NSD incidence.

  3. Sagittal venous sinus thrombosis after cesarean section: a case report

    Directory of Open Access Journals (Sweden)

    Farideh Keypour

    2013-07-01

    Full Text Available Background: Cerebral venous thrombosis (CVT is uncommon after cesarean section. Although it can be a leading cause of maternal mortality. CVT may occur during pregnancy because of hypercoagulable states such as preeclampsia, thrombophilias, antiphospholipid antibody syndrome and sepsis.Case presentation: A 31 years old woman G2 Ab1 at 37 weeks gestational age with  premature rupture of membrane underwent cesarean section because breech presentation and preeclampsia. Spinal anesthesia was done for emergent cesarean section. On the second day after cesarean section, she developed headache, vomiting, focal neurologic deficits, paresthesia, blurred vision. Brain magnetic resonance imaging (MRI showed thrombosis in anterior half of superior sagittal sinus. Treatment consisted of anticoagulation.  Conclusion: Thrombophilias, pregnancy-related hypertension and cesarean section are the predisposing factors for thromboembolism. Unfractionated heparin and low molecular weight heparin (LMWs are effective drugs for thromboprophylaxis. It is vital to prevent venous thrombosis to reduce mortality during both intrapartum and postpartum periods. Consideration of cerebral venous thrombosis in similar cases is recommended.

  4. Observational Consequences of Coronal Heating Mechanisms

    Science.gov (United States)

    Winebarger, Amy R.; Cirtain, Jonathan C.; Golub, Leon; Kobayashi, Ken

    2014-01-01

    The coronal heating problem remains unsolved today, 80 years after its discovery, despite 50 years of suborbital and orbital coronal observatories. Tens of theoretical coronal heating mechanisms have been suggested, but only a few have been able to be ruled out. In this talk, we will explore the reasons for the slow progress and discuss the measurements that will be needed for potential breakthrough, including imaging the solar corona at small spatial scales, measuring the chromospheric magnetic fields, and detecting the presence of high temperature, low emission measure plasma. We will discuss three sounding rocket instruments developed to make these measurements: the High resolution Resolution Coronal Imager (Hi-C), the Chromospheric Lyman-Alpha Spectropolarimeter (CLASP), and the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS).

  5. Multidimensional modeling of coronal rain dynamics

    CERN Document Server

    Fang, X; Keppens, R

    2013-01-01

    We present the first multidimensional, magnetohydrodynamic simulations which capture the initial formation and the long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in-situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match with modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into $V$-shaped like features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views on blobs which evaporate in situ, or get siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys o...

  6. Microwave Enhancement in Coronal Holes: Statistical Properties

    Indian Academy of Sciences (India)

    Ν. Gopalswamy; Κ. Shibasaki; Μ. Salem

    2000-09-01

    We report on the statistical properties of the microwave enhancement (brightness temperature, area, fine structure, life time and magnetic field strength) in coronal holes observed over a period of several solar rotations.

  7. Relating magnetic reconnection to coronal heating.

    Science.gov (United States)

    Longcope, D W; Tarr, L A

    2015-05-28

    It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are related--i.e. coronal reconnection generates heat. This attempt must address the fact that topological change of field lines does not automatically generate heat. We present one case of flux emergence where we have measured the rate of coronal magnetic reconnection and the rate of energy dissipation in the corona. The ratio of these two, [Formula: see text], is a current comparable to the amount of current expected to flow along the boundary separating the emerged flux from the pre-existing flux overlying it. We can generalize this relation to the overall corona in quiet Sun or in active regions. Doing so yields estimates for the contribution to coronal heating from magnetic reconnection. These estimated rates are comparable to the amount required to maintain the corona at its observed temperature.

  8. Coronal Magnetism and Forward Solarsoft Idl Package

    Science.gov (United States)

    Gibson, S. E.

    2014-12-01

    The FORWARD suite of Solar Soft IDL codes is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD may be used both to synthesize a broad range of coronal observables, and to access and compare to existing data. FORWARD works with numerical model datacubes, interfaces with the web-served Predictive Science Inc MAS simulation datacubes and the Solar Soft IDL Potential Field Source Surface (PFSS) package, and also includes several analytic models (more can be added). It connects to the Virtual Solar Observatory and other web-served observations to download data in a format directly comparable to model predictions. It utilizes the CHIANTI database in modeling UV/EUV lines, and links to the CLE polarimetry synthesis code for forbidden coronal lines. FORWARD enables "forward-fitting" of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties.

  9. Observational Properties of Coronal Mass Ejections

    Science.gov (United States)

    2006-01-01

    2003. Peameis, D.V., Magntetic topology of imspumlsive assd gradutal solar energetic particle Xic. H., L. Ofmran, and G. Lawvrence, Cone model for...425, 1097, 2004. Yashiro, S., N. Gopalssvamy, G. Michalek, assd R.A. Hosvard, Properties of narrow coronal Sltatstnigara~jU, A., Y.-i. Mootn, M. Dryer...G.M.,’FTit relatiomtslip hetwseen prominence ermtptions assd coronal mnass ejections.. 107(A8), 1223, doi: 10. 1029/2001 JAOO9 143, 2002. .1. Atssnn.s

  10. Evaluation of Fractured Condylar Head Along the Sagittal Plane: Report of Three Cases

    OpenAIRE

    Rajesh Kumar, Bekal Pattathan; Rai, Kirthi Kumar; Shiva Kumar, H. R.; Upasi, Amarnath P.; Shah, Ashwin

    2011-01-01

    There are case reports of sagittal fractures of the condylar head leading to bifid condyle. However bifid condyles maybe found in patients with no history of trauma. A split in the saggital plane of the condyle is not visible with a lateral, oblique or panaromic radiographs but only with anteriorposterior, transorbital projections or CT scan of the temperomandibular joint. The chances of condyle being split in the sagittal plane may be due to the medial pole extending beyond the condylar neck...

  11. Observational features of equatorial coronal hole jets

    CERN Document Server

    Nistico', G; Patsourakos, S; Zimbardo, G

    2010-01-01

    Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km/s, while the deceleration rate appears to be about 0.11 km/s2, less than solar gravity. The average jet visibility time is about 30 minutes, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and eq...

  12. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, X.; Xia, C.; Keppens, R. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2013-07-10

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  13. An Estimate of Solar Wind Density and Velocity Profiles in a Coronal Hole and a Coronal Streamer

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1996-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment (SCE) during the first solar conjunction in summer 1991, two data sets were selected, one associated with a coronal hole and the other associated with coronal streamer crossings. In order to determine coronal streamer density profiles, the electron content of the tracking passes embedded in a coronal streamer were corrected for the contributions from coronal hole densities.

  14. The Longitudinal Sagittal Growth Changes of Maxilla and Mandible According to Quantitative Cervical Vertebral Maturation

    Institute of Scientific and Technical Information of China (English)

    Lili CHEN; Jiuxiang LIN; Tianmin XU; Xiaosi LONG

    2009-01-01

    To investigate the longitudinal sagittal growth changes of maxilla and mandible according to the quantitative cervical vertebral maturation (QCVM) for adolescents with normal occlusion,mixed longitudinal data were used.The samples included 87 adolescents aged from 8 to 18 y old with normal occlusion (32 males,55 females) selected from 901 candidates.Sequential lateral cephalograms and hand-wrist films were taken once a year,lasting for 6 y.The longitudinal sagittal growth changes of maxilla and mandible according to QCVM were measured.There were some significant differences between maxilla and mandible according to QCVM.The sagittal growth change of maxilla showed a trend towards high velocity→decelerating velocity→completing velocity from QCVM stage Ⅰ to stage Ⅳ.The sagittal growth change of mandible showed a trend towards accelerating velocity→high velocity→decelerating velocity→completing velocity from QCVM stage Ⅰ to stage IV.With sagittal relationship,growth magnitude was almost the same between maxilla and mandible at QCVM stage Ⅰ.At stage Ⅱ the growth of mandible exceeded that of maxilla and growth in mandible continued at stages Ⅲ and Ⅳ,while the maxilla ceased to grow.Growth magnitude was greater and the growth duration was longer with male mandible.It is concluded that the longitudinal sagittal growth changes of maxilla and mandible on the basis of QCVM is of value in the orthodontic practice.

  15. Build Axial Gradient Field by Using Axial Magnetized Permanent Rings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Axial magnetic field produced by an axial magnetized permanent ring was studied. For two permanent rings, if they are magnetized in the same directions, a nearly uniform axial field can be produced. If they are magnetized in opposite direction,an axial gradient magnetic field can be generated, with the field range changing from -B0 to B0. A permanent magnet with a high axial gradient field was fabricated, the measured results agree with the PANDIRA calculation very well. For wider usage,it is desirable for the field gradient to be changed. Some methods to produce the variable gradient field are presented. These kinds of axial gradient magnetic field can also be used as a beam focusing for linear accelerator if the periodic field can be produced along the beam trajectory. The axial magnetic field is something like a solenoid, large stray field will leak to the outside environment if no method is taken to control them. In this paper, one method is illustrated to shield off the outside leakage field.

  16. Kelvin-Helmholtz instability in an Alfven resonant layer of a solar coronal loop

    Science.gov (United States)

    Uchimoto, E.; Strauss, H. R.; Lawson, W. S.

    1991-01-01

    A Kelvin-Helmholtz instability has been identified numerically on an azimuthally symmetric Alfven resonant layer in an axially bounded, straight cylindrical coronal loop. The set of equations is solved numerically as an initial value problem. The linear growth rate of this instability is shown to be approximately proportional to the Alfven driving amplitude and inversely proportional to the width of the Alfven resonant layer. It is also shown that the linear growth rate increases linearly with m - 1 up to a certain m, reaches its maximum value for the mode whose half wavelength is comparable to the Alfven resonant layer width, and decreases at higher azimuthal mode number.

  17. OBSERVATIONAL SIGNATURES OF CORONAL LOOP HEATING AND COOLING DRIVEN BY FOOTPOINT SHUFFLING

    Energy Technology Data Exchange (ETDEWEB)

    Dahlburg, R. B.; Taylor, B. D. [LCP and FD, Naval Research Laboratory, Washington, DC 20375 (United States); Einaudi, G. [Berkeley Research Associates, Inc., Beltsville, MD 20705 (United States); Ugarte-Urra, I. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Rappazzo, A. F. [Advanced Heliophysics, Pasadena, CA 91106 (United States); Velli, M., E-mail: rdahlbur@lcp.nrl.navy.mil [EPSS, UCLA, Los Angeles, CA 90095 (United States)

    2016-01-20

    The evolution of a coronal loop is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. The footpoints of the loop magnetic field are advected by random motions. As a consequence, the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is nonuniformly distributed so that only a fraction of the coronal mass and volume gets heated at any time. Temperature and density are highly structured at scales that, in the solar corona, remain observationally unresolved: the plasma of our simulated loop is multithermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Numerical simulations of coronal loops of 50,000 km length and axial magnetic field intensities ranging from 0.01 to 0.04 T are presented. To connect these simulations to observations, we use the computed number densities and temperatures to synthesize the intensities expected in emission lines typically observed with the Extreme Ultraviolet Imaging Spectrometer on Hinode. These intensities are used to compute differential emission measure distributions using the Monte Carlo Markov Chain code, which are very similar to those derived from observations of solar active regions. We conclude that coronal heating is found to be strongly intermittent in space and time, with only small portions of the coronal loop being heated: in fact, at any given time, most of the corona is cooling down.

  18. Dissipative Axial Inflation

    CERN Document Server

    Notari, Alessio

    2016-01-01

    We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...

  19. Static and dynamic loading of mandibular condyles and their positional changes after bilateral sagittal split advancement osteotomies.

    Science.gov (United States)

    Dicker, G J; Tuijt, M; Koolstra, J H; Van Schijndel, R A; Castelijns, J A; Tuinzing, D B

    2012-09-01

    This study analysed the effects of change of direction of masseter (MAS) and medial pterygoid muscles (MPM) and changes of moment arms of MAS, MPM and bite force on static and dynamic loading of the condyles after surgical mandibular advancement. Rotations of the condyles were assessed on axial MRIs. 16 adult patients with mandibular hypoplasia were studied. The mandibular plane angle (MPA) was 39° in Group II (n=8). All mandibles were advanced with a bilateral sagittal split osteotomy (BSSO). In Group II, BSSO was combined with Le Fort I osteotomy. Pre and postoperative moment arms of MAS, MPM and bite force were used in a two-dimensional model to assess static loading of the condyles. Pre and postoperative data on muscle cross-sectional area, volume and direction were introduced in three-dimensional dynamic models of the masticatory system to assess the loading of the condyles during opening and closing. Postsurgically, small increases of static condylar loading were calculated. Dynamic loading decreased slightly. Minor rotations of the condyles were observed. The results do not support the idea that increased postoperative condylar loading is a serious cause for condylar resorption or relapse.

  20. Coronal "wave": Magnetic Footprint Of A Cme?

    Science.gov (United States)

    Attrill, Gemma; Harra, L. K.; van Driel-Gesztelyi, L.; Demoulin, P.; Wuelser, J.

    2007-05-01

    We propose a new mechanism for the generation of "EUV coronal waves". This work is based on new analysis of data from SOHO/EIT, SOHO/MDI & STEREO/EUVI. Although first observed in 1997, the interpretation of coronal waves as flare-induced or CME-driven remains a debated topic. We investigate the properties of two "classical" SOHO/EIT coronal waves in detail. The source regions of the associated CMEs possess opposite helicities & the coronal waves display rotations in opposite senses. We observe deep dimmings near the flare site & also widespread diffuse dimming, accompanying the expansion of the EIT wave. We report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions & simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behaviour is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME & quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings & widespread diffuse dimming are identified as innate characteristics of this process. In addition we present some of the first analysis of a STEREO/EUVI limb coronal wave. We show how the evolution of the diffuse bright front & dimmings can be understood in terms of the model described above. We show that an apparently stationary part of the bright front can be understood in terms of magnetic interchange reconnections between the expanding CME & the "open" magnetic field of a low-latitude coronal hole. We use both the SOHO/EIT & STEREO/EUVI events to demonstrate that through successive reconnections, this new model provides a natural mechanism via which CMEs can become large-scale in the lower corona.

  1. Study of axial magnetic effect

    Energy Technology Data Exchange (ETDEWEB)

    Braguta, Victor [IHEP, Protvino, Moscow region, 142284 Russia ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Chernodub, M. N. [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université François-Rabelais Tours, Fédération Denis Poisson, Parc de Grandmont, 37200 Tours, France Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Goy, V. A. [School of Natural Sciences, Far Eastern Federal University, Sukhanova street 8, Vladivostok, 690950 (Russian Federation); Landsteiner, K. [Instituto de Física Teórica UAM/CSIC, C/ Nicolás Cabrera 13-15, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Molochkov, A. V. [School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Ulybyshev, M. [ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 Russia Institute for Theoretical Problems of Microphysics, Moscow State University, Moscow, 119899 (Russian Federation)

    2016-01-22

    The Axial Magnetic Effect manifests itself as an equilibrium energy flow of massless fermions induced by the axial (chiral) magnetic field. Here we study the Axial Magnetic Effect in the quenched SU(2) lattice gauge theory with massless overlap fermions at finite temperature. We numerically observe that in the low-temperature hadron phase the effect is absent due to the quark confinement. In the high-temperature deconfinement phase the energy flow is an increasing function of the temperature which reaches the predicted asymptotic T{sup 2} behavior at high temperatures. We find, however, that energy flow is about one order of magnitude lower compared to a theoretical prediction.

  2. Spinal sagittal imbalance in patients with lumbar disc herniation: its spinopelvic characteristics, strength changes of the spinal musculature and natural history after lumbar discectomy

    OpenAIRE

    Liang, Chen; Sun, Jianmin; Cui, Xingang; Jiang, Zhensong; Zhang, Wen; Li, Tao

    2016-01-01

    Background Spinal sagittal imbalance is a widely acknowledged problem, but there is insufficient knowledge regarding its occurrence. In some patients with lumbar disc herniation (LDH), their symptom is similar to spinal sagittal imbalance. The aim of this study is to illustrate the spinopelvic sagittal characteristics and identity the role of spinal musculature in the mechanism of sagittal imbalance in patients with LDH. Methods Twenty-five adults with spinal sagittal imbalance who initially ...

  3. 低场 MR 斜冠状位 GRE T2∗WI 序列对急性前交叉韧带损伤的诊断价值%Diagnostic value of GRE T2 * WI sequences in low field strength MR with oblique coronal plane in acute anterior cruciate ligament injury

    Institute of Scientific and Technical Information of China (English)

    李杰; 陈京美; 陈钰辉; 王永述

    2015-01-01

    Objective To explore the diagnostic value of GRE T2 ∗ WI sequences in low field strength MR with oblique coronal plane in patients with acute anterior cruciate ligament (ACL)injury.Methods 68 cases of acute traumatic hemarthrosis of the knee joint proved surgically were reviewed.The cases were divided into two groups:conventional MR group (axial image,standard coro-nal image and sagittal oblique image),and conventional with oblique coronal MR group.The diagnostic results with surgical and path-ological results were compared.The diagnostic accuracy of two images were evaluated respectively.Results For conventional MR group and conventional with oblique coronal MR group,the sensitivities in diagnosing ACL were 72.9% and 97.9%,the specificities were 80% and 85%,the positive predictive values were 89.7% and 94%,the negative predictive values were 55.2% and 85%,the accuracies were 52.9% and 82.9%,the misdiagnosis rates were 20% and 1 5%,the missed diagnosis rates were 27.1% and 2.1%, and the coincidence rates was 75% and 94.1%,respectively.The difference in diagnosis rates between two groups were statistically significant(P <0.05).Conclusion GRE T2 ∗ WI sequences with oblique coronal plane can significantly improve the diagnostic rate of anterior cruciate ligament injury.%目的:探讨低场 MR 梯度回波(GRE)T2∗ WI 序列斜冠状位扫描对急性前交叉韧带(ACL)损伤的诊断价值。方法对68例经手术证实的膝关节急性损伤病例进行回顾性分析,将病例分为常规扫描组(轴位、冠状位、斜矢状位)及常规+斜冠状位扫描组,将成像结果与手术结果对比,分别评价常规扫描与常规+斜冠位扫描对 ACL 有无损伤诊断的准确性。结果常规扫描组诊断ACL 损伤的敏感度为72.9%,特异度为80%,阳性预测值为89.7%,阴性预测值为55.2%,正确指数为52.9%,误诊率为20%,漏诊率为27.1%,诊断符合率为75%;常规+斜冠状位扫描组诊断 ACL 损伤的敏感度为97.9%,

  4. Sagittal plane analysis of the spine and pelvis in adult idiopathic scoliosis

    Institute of Scientific and Technical Information of China (English)

    LI Wei-shi; LI Gang; CHEN Zhong-qiang; Kirkham B Wood

    2010-01-01

    Background There has been an increasing recognition of the importance of sagittal spinopelvic alignment in patients with scoliosis as it relates to clinical outcomes. However, the changes seen in sagittal spinopelvic alignment in adult idiopathic scoliosis patients is poorly defined. This study was conducted to evaluate the sagittal alignment of pelvis and spine in adult idiopathic scoliosis patients.Methods The sagittal parameters of the spine and pelvis were analyzed in lateral standing radiographs of 124 patients (mean age 47.4 years) with adult idiopathic scoliosis, including thoracic kyphosis (TK), thoracolumbar junction kyphosis (TLJ), lumbar lordosis (LL), pelvic incidence (PI), sacrum slope (SS), pelvic tilt (PT) and C7 plumb line (C7PL). The patients were divided into three groups according to the age: 20-40 years, 41-64 years, and ≥65 years. The parameters were compared with those in normal adults and adolescent idiopathic scoliosis (AIS) patients. The relationship between all parameters as well as age and sagittal parameters were analyzed.Results The PI in patients with adult idiopathic scoliosis was 58.1°±13.0°, which was significantly higher than that in normal adults. The PT (19.9°±10.6°) was also higher than that in both normal adults and AIS patients, while the SS (38.1°±12.0°) was similar or smaller. As age increased, C7PL, PT and TJL increased while LL decreased. There was no relationship between age and both PI and TK. PT had the strongest statistical association with the C7PL.Conclusions PI is higher in adult idiopathic scoliosis than normal subjects. The PT is the most relevant pelvic parameter to the global sagittal alignment of the spine. Age significantly influences sagittal parameters of the spine and pelvis except the PI and TK.

  5. Reproduction of superior sagittal sinus animal model by bypass transplantation of biomaterial graft

    Directory of Open Access Journals (Sweden)

    Qing-yong LUO

    2011-03-01

    Full Text Available Objective To establish the beagles model of superior sagittal sinus bypass graft,and explore the feasibility of reconstruction of superior sagittal sinus with biomaterials using this model.Methods Eight adult male beagles(weight: 12.5-22.0kg were involved in the present study.The superior sagittal sinus was exposed and blocked via bone window,and then anastomosed side-to-end to the biomaterial graft under the dedicated microscope of neurosurgery surgery,expectant treatment such as anti-inflammatory was given for the animals.The digital subtraction venography(DSV and color Doppler flow imaging(CDFI of superior sagittal sinus were performed in 1,2,4 and 8 weeks after the operation.Eight weeks after the operation,all the animals were sacrificed and the material graft was examined histologically.Results The DSV and CDFI of superior sagittal sinus showed that the stomas of 2 beagles were with slight stenosis and high flow velocity,of 1 beagle with small leakage and low flow velocity,while of other 5 beagles were normal.The histological examination showed endothelial cells were growing on the graft and superior sagittal sinus,and crawling toward the lumen of graft 8 weeks after the operation.Conclusion The beagles model of superior sagittal sinus bypass graft was established successfully.The short-term effect of the model was satisfactory,while further work should be performed to determine the long-term effects.

  6. Ectopic folliculosebaceous units at the coronal sulcus.

    Science.gov (United States)

    Fernandez-Flores, Angel

    2014-12-01

    Tyson glands were described in the 17th century as modified sebaceous glands of the coronal sulcus of the penis. However, this description and other early texts supporting the existence of Tyson glands were not accompanied by illustrations. The existence of such glands has been passing through the literature without adequate graphical demonstration, which has contributed to controversial debates. Herein we present a case of a partial penectomy performed on a 65-year-old man with a squamous cell carcinoma of the penis. In this case we identified sebaceous glands as well as folliculosebaceous units in the coronal sulcus. We also comparatively examined 12 cases of partial penectomy to search for sebaceous glands or folliculosebaceous units in the coronal sulcus or the preputium. We found neither sebaceous glands nor folliculosebaceous units at the coronal sulcus or the mucosal aspect of the prepuce. We conclude that: (1) folliculosebaceous units are possible in the coronal sulcus, as the current case illustrates for the first time in literature and (2) the current case is an oddity, probably induced by the accompanying squamous cell carcinoma, and therefore it may represent an ectopic folliculosebaceous unit rather than an anatomic variation.

  7. Evaluations of multiplanar reconstruction in CT recognition of lumbar disk disease

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, D.I.; Stauffer, A.E.; Davis, K.R.; Ganott, M.; Taveras, J.M.

    1984-07-01

    Axial computed tomographic (CT) images were compared with sagittal and coronal reformations and myelograms in 60 patients to evaluate the diagnostic usefulness of multiplanar reconstructions for the recognition of lumbar disk disease. The axial CT scans were most sensitive and specific. The sagittal scans were helpful in evaluating the neural foramina, the size of the disk bulge into the spinal canal, especially at L5-S1, and patients with spondylolisthesis. The coronal images were the least informative, although they contributed to the evaluation of lumbar nerve roots. The myelograms and the sagittal images were equally useful in the detection of herniated disk, but axial scans were superior to either. It was concluded that reformatted sagittal and coronal images are not required if all axial images are normal.

  8. Dissipative axial inflation

    Science.gov (United States)

    Notari, Alessio; Tywoniuk, Konrad

    2016-12-01

    We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term phi/fγ F ~F, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density ρR, which can lead to inflation without the need of a flat potential. We analyze the system, for momenta k smaller than the cutoff fγ, including the backreaction numerically. We consider the evolution from a given static initial condition and explicitly show that, if fγ is smaller than the field excursion phi0 by about a factor of at least Script O (20), there is a friction effect which turns on before the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of perturbations, scalars and tensors. Such oscillations have a period of 4-5 efolds and an amplitude which is typically less than a few percent and decreases linearly with fγ. We also stress that the curvature perturbation on uniform density slices should be sensitive to slow-roll parameters related to ρR rather than dot phi2/2 and we discuss the existence of friction terms acting on the perturbations, although we postpone a calculation of the power spectrum and of non-gaussianity to future work and we simply define and compute suitable slow roll parameters. Finally we stress that this scenario may be realized in the axion case, if the coupling 1/fγ to U(1) (photons) is much larger than the coupling 1/fG to non-abelian gauge fields (gluons), since the latter sets the range of the potential and therefore the maximal allowed phi0~ fG.

  9. The sagittal balance of the spine in children and adolescents with osteogenesis imperfecta.

    Science.gov (United States)

    Abelin, Karimane; Vialle, Raphaël; Lenoir, Thibault; Thévenin-Lemoine, Camille; Damsin, Jean-Paul; Forin, Véronique

    2008-12-01

    In severe forms of osteogenesis imperfecta, multiple compression fractures of the spine, as well as vertebral height shortening could be responsible for an increased thoracic kyphosis or a diminished lumbar lordosis. Theses progressive changes in sagittal shapes of the trunk could be responsible for a global sagittal trunk imbalance. We compare the parameters of sagittal spinopelvic balance in young patients with OI to those parameters in a control group of healthy volunteers. Eighteen patients with osteogenesis imperfecta were compared to a cohort of 300 healthy volunteers. A standing lateral radiograph of the spine was obtained in a standardized fashion. The sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, thoracic kyphosis, T1 and T9 sagittal offset were measured using a computer-assisted method. The variations and reciprocal correlations of all parameters in both groups according to each other were studied. Comparison of angular parameters between OI patients and control group showed an increased T1T12 kyphosis in OI patients. T1 and T9 sagittal offset was positive in OI patients and negative in control group. This statistically significant difference among sagittal offsets in both groups indicated that OI patients had a global sagittal balance of the trunk displaced anteriorly when compared to the normal population. Reciprocal correlations between angular parameters in OI patients showed a strong correlation between lumbar lordosis (L1L5 and L1S1) and sacral slope. The T9 sagittal offset was also strongly correlated with pelvic tilt. Pelvic incidence was correlated with L1S1 lordosis, T1 sagittal offset and pelvic tilt. In OI patients, the T1T12 thoracic kyphosis was statistically higher than in control group and was not correlated with other shape (LL) or pelvic (SS, PT or PI) parameters. Because isolated T1T12 kyphosis increase without T4T12 significant modification, we suggest that vertebral deformations worsen in OI patients at the upper part

  10. DIRECT OBSERVATION OF SOLAR CORONAL MAGNETIC FIELDS BY VECTOR TOMOGRAPHY OF THE CORONAL EMISSION LINE POLARIZATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, M. [Physics Department, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Lin, H. [Institute for Astronomy, University of Hawaii at Manoa, 34 Ohia Ku Street, Pukalani, Maui, HI 96768 (United States); Tomczyk, S., E-mail: kramar@cua.edu, E-mail: lin@ifa.hawaii.edu, E-mail: tomczyk@ucar.edu [High Altitude Observatory, 3080 Center Green Drive, Boulder, CO 80301 (United States)

    2016-03-10

    We present the first direct “observation” of the global-scale, 3D coronal magnetic fields of Carrington Rotation (CR) Cycle 2112 using vector tomographic inversion techniques. The vector tomographic inversion uses measurements of the Fe xiii 10747 Å Hanle effect polarization signals by the Coronal Multichannel Polarimeter (CoMP) and 3D coronal density and temperature derived from scalar tomographic inversion of Solar Terrestrial Relations Observatory (STEREO)/Extreme Ultraviolet Imager (EUVI) coronal emission lines (CELs) intensity images as inputs to derive a coronal magnetic field model that best reproduces the observed polarization signals. While independent verifications of the vector tomography results cannot be performed, we compared the tomography inverted coronal magnetic fields with those constructed by magnetohydrodynamic (MHD) simulations based on observed photospheric magnetic fields of CR 2112 and 2113. We found that the MHD model for CR 2112 is qualitatively consistent with the tomography inverted result for most of the reconstruction domain except for several regions. Particularly, for one of the most noticeable regions, we found that the MHD simulation for CR 2113 predicted a model that more closely resembles the vector tomography inverted magnetic fields. In another case, our tomographic reconstruction predicted an open magnetic field at a region where a coronal hole can be seen directly from a STEREO-B/EUVI image. We discuss the utilities and limitations of the tomographic inversion technique, and present ideas for future developments.

  11. Free Magnetic Energy and Coronal Heating

    Science.gov (United States)

    Winebarger, Amy; Moore, Ron; Falconer, David

    2012-01-01

    Previous work has shown that the coronal X-ray luminosity of an active region increases roughly in direct proportion to the total photospheric flux of the active region's magnetic field (Fisher et al. 1998). It is also observed, however, that the coronal luminosity of active regions of nearly the same flux content can differ by an order of magnitude. In this presentation, we analyze 10 active regions with roughly the same total magnetic flux. We first determine several coronal properties, such as X-ray luminosity (calculated using Hinode XRT), peak temperature (calculated using Hinode EIS), and total Fe XVIII emission (calculated using SDO AIA). We present the dependence of these properties on a proxy of the free magnetic energy of the active region

  12. A Contemporary View of Coronal Heating

    CERN Document Server

    Parnell, Clare E; 10.1098/rsta.2012.0113

    2012-01-01

    Determining the heating mechanism (or mechanisms) that causes the outer atmosphere of the Sun, and many other stars, to reach temperatures orders of magnitude higher than their surface temperatures has long been a key problem. For decades the problem has been known as the coronal heating problem, but it is now clear that `coronal heating' cannot be treated or explained in isolation and that the heating of the whole solar atmosphere must be studied as a highly coupled system. The magnetic field of the star is known to play a key role, but, despite significant advancements in solar telescopes, computing power and much greater understanding of theoretical mechanisms, the question of which mechanism or mechanisms are the dominant supplier of energy to the chromosphere and corona is still open. Following substantial recent progress, we consider the most likely contenders and discuss the key factors that have made, and still make, determining the actual (coronal) heating mechanism (or mechanisms) so difficult.

  13. Coronal heating in multiple magnetic threads

    CERN Document Server

    Tam, K V; Browning, P K; Cargill, P J

    2015-01-01

    Context. Heating the solar corona to several million degrees requires the conversion of magnetic energy into thermal energy. In this paper, we investigate whether an unstable magnetic thread within a coronal loop can destabilise a neighbouring magnetic thread. Aims. By running a series of simulations, we aim to understand under what conditions the destabilisation of a single magnetic thread can also trigger a release of energy in a nearby thread. Methods. The 3D magnetohydrodynamics code, Lare3d, is used to simulate the temporal evolution of coronal magnetic fields during a kink instability and the subsequent relaxation process. We assume that a coronal magnetic loop consists of non-potential magnetic threads that are initially in an equilibrium state. Results. The non-linear kink instability in one magnetic thread forms a helical current sheet and initiates magnetic reconnection. The current sheet fragments, and magnetic energy is released throughout that thread. We find that, under certain conditions, this ...

  14. A unified theory of coronal heating

    Science.gov (United States)

    Ionson, J. A.

    1985-01-01

    Solar coronal heating mechanisms are analyzed within the framework of a unified theory of heating processes. The theory is based on the standing wave equation of Ionson (1982) for the global current driven by emfs from the convection Beta less than 1. The equation has the same form as a driven LRC equation in which the equivalent inductance is scaled with the coronal loop length. The theory is used to classify various heating mechanisms inside the coronal loops. It is shown that the total global current can be obtained from an integration of the local currents, the degree of coherency between local currents being the dominant factor governing the global current amplitude. Active region loops appear to be heated by electrodynamic coupling to p-mode oscillations in the convection Beta less than 1.

  15. The Fundamental Structure of Coronal Loops

    Science.gov (United States)

    Winebarger, Amy; Warren, Harry; Cirtain, Jonathan; Kobayashi, Ken; Korreck, Kelly; Golub, Leon; Kuzin, Sergey; Walsh, Robert; DePontieu, Bart; Title, Alan; Weber, Mark

    2012-01-01

    During the past ten years, solar physicists have attempted to infer the coronal heating mechanism by comparing observations of coronal loops with hydrodynamic model predictions. These comparisons often used the addition of sub ]resolution strands to explain the observed loop properties. On July 11, 2012, the High Resolution Coronal Imager (Hi ]C) was launched on a sounding rocket. This instrument obtained images of the solar corona was 0.2 ]0.3'' resolution in a narrowband EUV filter centered around 193 Angstroms. In this talk, we will compare these high resolution images to simultaneous density measurements obtained with the Extreme Ultraviolet Imaging Spectrograph (EIS) on Hinode to determine whether the structures observed with Hi ]C are resolved.

  16. Magnetohydrodynamic Modeling of Coronal Evolution and Disruption

    Science.gov (United States)

    Linker, Jon

    2002-01-01

    Flux cancellation, defined observationally as the mutual disappearance of magnetic fields of opposite polarity at the neutral line separating them, has been found to occur frequently at the site of filaments (called prominences when observed on the limb of the Sun). During the second year of this project, we have studied theoretically the role that flux cancellation may play in prominence formation, prominence eruption, and the initiation of coronal mass ejections. This work has been in published in two papers: "Magnetic Field Topology in Prominences" by Lionello, Mikic, Linker, and Amari and "Flux Cancellation and Coronal Mass Ejections" by Linker, Mikic, Riley, Lionello, Amari, and Odstrcil.

  17. Influence of implant rod curvature on sagittal correction of scoliosis deformity

    DEFF Research Database (Denmark)

    Salmingo, Remel A.; Tadano, Shigeru; Abe, Yuichiro;

    2014-01-01

    BACKGROUND CONTEXT: Deformation of in vivo–implanted rods could alter the scoliosis sagittal correction. To our knowledge, no previous authors have investigated the influence of implanted-rod deformation on the sagittal deformity correction during scoliosis surgery. PURPOSE: To analyze the changes...... of the implant rod’s angle of curvature during surgery and establish its influence on sagittal correction of scoliosis deformity. STUDY DESIGN: A retrospective analysis of the preoperative and postoperative implant rod geometry and angle of curvature was conducted. PATIENT SAMPLE: Twenty adolescent idiopathic...... scoliosis patients underwent surgery. Average age at the time of operation was 14 years. OUTCOME MEASURES: The preoperative and postoperative implant rod angle of curvature expressed in degrees was obtained for each patient. METHODS: Two implant rods were attached to the concave and convex side...

  18. Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns.

    Science.gov (United States)

    Steenen, S A; Becking, A G

    2016-07-01

    An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches.

  19. [The theoretical substantiation of myofunctional correction of sagittal occlusion abnormalities and temporomandibular joint dysfunction].

    Science.gov (United States)

    Danilova, M A; Ishmurzin, P V; Zakharov, S V

    2012-01-01

    Simulation in 3D-model of skeletal forms of sagittal malocclusion revealed tendency in tonus' modification of muscles of mastication in formation of distal and mesial occlusion. It's shown that distal occlusion is characterized by hypotonic condition of muscles of mastication, except posterior fibers of temporal muscle. Mesial occlusion is characterized by complex combination of muscle tone with prevalence of hypotonic condition of anterior fibers of temporal muscle, superficial portion of masseter muscle and medial pterygoid muscle. We have detected that using of myofunctional devices in treatment of sagittal malocclusion, temporomandibular joint dysfunction promotes of tone increasing of muscles of mastication.

  20. Coronal temperature profiles obtained from kinetic models and from coronal brightness measurements obtained during solar eclipses

    CERN Document Server

    Pierrard, V; Lemaire, J F

    2012-01-01

    Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are compared with those determined from a kinetic collisionless/exospheric model of the solar corona. This comparison indicates rather similar distributions at large radial distances (> 7 Rs) in the collisionless region. However, rather important differences are found close to the Sun in the acceleration region of the solar wind. The exospheric heat flux is directed away from the Sun, while that inferred from all WL coronal observations is in the opposite direction, i.e., conducting heat from the inner corona toward the chromosphere. This could indicate that the source of coronal heating rate extends up into the inner corona where it maximizes at r > 1.5 Rs well above the transition region.

  1. Large-scale Globally Propagating Coronal Waves

    Directory of Open Access Journals (Sweden)

    Alexander Warmuth

    2015-09-01

    Full Text Available Large-scale, globally propagating wave-like disturbances have been observed in the solar chromosphere and by inference in the corona since the 1960s. However, detailed analysis of these phenomena has only been conducted since the late 1990s. This was prompted by the availability of high-cadence coronal imaging data from numerous spaced-based instruments, which routinely show spectacular globally propagating bright fronts. Coronal waves, as these perturbations are usually referred to, have now been observed in a wide range of spectral channels, yielding a wealth of information. Many findings have supported the “classical” interpretation of the disturbances: fast-mode MHD waves or shocks that are propagating in the solar corona. However, observations that seemed inconsistent with this picture have stimulated the development of alternative models in which “pseudo waves” are generated by magnetic reconfiguration in the framework of an expanding coronal mass ejection. This has resulted in a vigorous debate on the physical nature of these disturbances. This review focuses on demonstrating how the numerous observational findings of the last one and a half decades can be used to constrain our models of large-scale coronal waves, and how a coherent physical understanding of these disturbances is finally emerging.

  2. Coronal bright points associated with minifilament eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Li, Haidong [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Yang, Bo; Yang, Dan, E-mail: hjcsolar@ynao.ac.cn [Also at Graduate School of Chinese Academy of Sciences, Beijing, China. (China)

    2014-12-01

    Coronal bright points (CBPs) are small-scale, long-lived coronal brightenings that always correspond to photospheric network magnetic features of opposite polarity. In this paper, we subjectively adopt 30 CBPs in a coronal hole to study their eruptive behavior using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. About one-quarter to one-third of the CBPs in the coronal hole go through one or more minifilament eruption(s) (MFE(s)) throughout their lifetimes. The MFEs occur in temporal association with the brightness maxima of CBPs and possibly result from the convergence and cancellation of underlying magnetic dipoles. Two examples of CBPs with MFEs are analyzed in detail, where minifilaments appear as dark features of a cool channel that divide the CBPs along the neutral lines of the dipoles beneath. The MFEs show the typical rising movements of filaments and mass ejections with brightenings at CBPs, similar to large-scale filament eruptions. Via differential emission measure analysis, it is found that CBPs are heated dramatically by their MFEs and the ejected plasmas in the MFEs have average temperatures close to the pre-eruption BP plasmas and electron densities typically near 10{sup 9} cm{sup –3}. These new observational results indicate that CBPs are more complex in dynamical evolution and magnetic structure than previously thought.

  3. Observing coronal nanoflares in active region moss

    CERN Document Server

    Testa, Paola; Martinez-Sykora, Juan; DeLuca, Ed; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Golub, Leon; Kobayashi, Ken; Korreck, Kelly; Kuzin, Sergey; Walsh, Robert; DeForest, Craig; Title, Alan; Weber, Mark

    2013-01-01

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial (~0.3-0.4 arcsec) and temporal (5.5s) resolution. The Hi-C observations show in some moss regions variability on timescales down to ~15s, significantly shorter than the minute scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by SDO/AIA in the 94A channel, and by Hinode/XRT. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few $10^{23}rg, also supporting the nanoflare scenario. These Hi-C...

  4. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    Energy Technology Data Exchange (ETDEWEB)

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark [Smithsonian Astrophysical Observatory, 60 Garden street, MS 58, Cambridge, MA 02138 (United States); De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan [Lockheed Martin Solar and Astrophysics Lab, Org. A021S, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Hansteen, Viggo [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Kuzin, Sergey [P. N. Lebedev Physical institute of the Russian Academy of Sciences, Leninskii prospekt, 53, 119991 Moscow (Russian Federation); Walsh, Robert [University of Central Lancashire, Lancashire, Preston PR1 2HE (United Kingdom); DeForest, Craig, E-mail: ptesta@cfa.harvard.edu [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  5. Magnetic Topology of Coronal Hole Linkages

    Science.gov (United States)

    Titov, V. S.; Mikic, Z.; Linker, J. A.; Lionello, R.; Antiochos, S. K.

    2010-01-01

    In recent work, Antiochos and coworkers argued that the boundary between the open and closed field regions on the Sun can be extremely complex with narrow corridors of open ux connecting seemingly disconnected coronal holes from the main polar holes, and that these corridors may be the sources of the slow solar wind. We examine, in detail, the topology of such magnetic configurations using an analytical source surface model that allows for analysis of the eld with arbitrary resolution. Our analysis reveals three important new results: First, a coronal hole boundary can join stably to the separatrix boundary of a parasitic polarity region. Second, a single parasitic polarity region can produce multiple null points in the corona and, more important, separator lines connecting these points. Such topologies are extremely favorable for magnetic reconnection, because it can now occur over the entire length of the separators rather than being con ned to a small region around the nulls. Finally, the coronal holes are not connected by an open- eld corridor of finite width, but instead are linked by a singular line that coincides with the separatrix footprint of the parasitic polarity. We investigate how the topological features described above evolve in response to motion of the parasitic polarity region. The implications of our results for the sources of the slow solar wind and for coronal and heliospheric observations are discussed.

  6. Role of Magnetic Carpet in Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma; Diksha Chaudhary

    2008-03-01

    One of the fundamental questions in solar physics is how the solar corona maintains its high temperature of several million Kelvin above photosphere with a temperature of 6000 K. Observations show that solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in the solar corona. The separate kinds of coronal loops may also be heated by different mechanisms. Using data from instruments onboard the Solar and Heliospheric Observatory (SOHO) and from the more recent Transition Region and Coronal Explorer (TRACE) scientists have identified small regions of mixed polarity, termed magnetic carpet contributing to solar activity on a short time scale. Magnetic loops of all sizes rise into the solar corona, arising from regions of opposite magnetic polarity in the photosphere. Energy released when oppositely directed magnetic fields meet in the corona is one likely cause for coronal heating. There is enough energy coming up from the loops of the “magnetic carpet” to heat the corona to its known temperature.

  7. Genesis Solar Wind Interstream, Coronal Hole and Coronal Mass Ejection Samples: Update on Availability and Condition

    Science.gov (United States)

    Allton, J. H.; Gonzalez, C. P.; Allums, K. K.

    2017-01-01

    Recent refinement of analysis of ACE/SWICS data (Advanced Composition Explorer/Solar Wind Ion Composition Spectrometer) and of onboard data for Genesis Discovery Mission of 3 regimes of solar wind at Earth-Sun L1 make it an appropriate time to update the availability and condition of Genesis samples specifically collected in these three regimes and currently curated at Johnson Space Center. ACE/SWICS spacecraft data indicate that solar wind flow types emanating from the interstream regions, from coronal holes and from coronal mass ejections are elementally and isotopically fractionated in different ways from the solar photosphere, and that correction of solar wind values to photosphere values is non-trivial. Returned Genesis solar wind samples captured very different kinds of information about these three regimes than spacecraft data. Samples were collected from 11/30/2001 to 4/1/2004 on the declining phase of solar cycle 23. Meshik, et al is an example of precision attainable. Earlier high precision laboratory analyses of noble gases collected in the interstream, coronal hole and coronal mass ejection regimes speak to degree of fractionation in solar wind formation and models that laboratory data support. The current availability and condition of samples captured on collector plates during interstream slow solar wind, coronal hole high speed solar wind and coronal mass ejections are de-scribed here for potential users of these samples.

  8. Using coronal seismology to estimate the magnetic field strength in a realistic coronal model

    CERN Document Server

    Chen, Feng

    2015-01-01

    Coronal seismology is extensively used to estimate properties of the corona, e.g. the coronal magnetic field strength are derived from oscillations observed in coronal loops. We present a three-dimensional coronal simulation including a realistic energy balance in which we observe oscillations of a loop in synthesised coronal emission. We use these results to test the inversions based on coronal seismology. From the simulation of the corona above an active region we synthesise extreme ultraviolet (EUV) emission from the model corona. From this we derive maps of line intensity and Doppler shift providing synthetic data in the same format as obtained from observations. We fit the (Doppler) oscillation of the loop in the same fashion as done for observations to derive the oscillation period and damping time. The loop oscillation seen in our model is similar to imaging and spectroscopic observations of the Sun. The velocity disturbance of the kink oscillation shows an oscillation period of 52.5s and a damping tim...

  9. Standing sausage modes in curved coronal slabs

    Science.gov (United States)

    Pascoe, D. J.; Nakariakov, V. M.

    2016-09-01

    Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.

  10. A Two-Fluid, MHD Coronal Model

    Science.gov (United States)

    Suess, S. T.; Wang, A.-H.; Wu, S. T.; Poletto, G.; McComas, D. J.

    1999-01-01

    We describe first results from a numerical two-fluid MHD model of the global structure of the solar Corona. The model is two-fluid in the sense that it accounts for the collisional energy exchange between protons and electrons. As in our single-fluid model, volumetric heat and Momentum sources are required to produce high speed wind from Corona] holes, low speed wind above streamers, and mass fluxes similar to the empirical solar wind. By specifying different proton and electron heating functions we obtain a high proton temperature in the coronal hole and a relatively low proton temperature above the streamer (in comparison with the electron temperature). This is consistent with inferences from SOHO/UltraViolet Coronagraph Spectrometer instrument (UVCS), and with the Ulysses/Solar Wind Observations Over the Poles of the Sun instrument (SWOOPS) proton and electron temperature measurements which we show from the fast latitude scan. The density in the coronal hole between 2 and 5 solar radii (2 and 5 R(sub S)) is similar to the density reported from SPARTAN 201.-01 measurements by Fisher and Guhathakurta [19941. The proton mass flux scaled to 1 AU is 2.4 x 10(exp 8)/sq cm s, which is consistent with Ulysses observations. Inside the closed field region, the density is sufficiently high so that the simulation gives equal proton and electron temperatures due to the high collision rate. In open field regions (in the coronal hole and above the streamer) the proton and electron temperatures differ by varying amounts. In the streamer the temperature and density are similar to those reported empirically by Li et al. [1998], and the plasma beta is larger than unity everywhere above approx. 1.5 R(sub S), as it is in all other MHD coronal streamer models [e.g., Steinolfson et al., 1982; also G. A. Gary and D. Alexander, Constructing the coronal magnetic field, submitted to Solar Physics, 1998].

  11. Nonlinear Force-free Coronal Magnetic Stereoscopy

    Science.gov (United States)

    Chifu, Iulia; Wiegelmann, Thomas; Inhester, Bernd

    2017-03-01

    Insights into the 3D structure of the solar coronal magnetic field have been obtained in the past by two completely different approaches. The first approach are nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms as boundary condition. The second approach uses stereoscopy of coronal magnetic loops observed in EUV coronal images from different vantage points. Both approaches have their strengths and weaknesses. Extrapolation methods are sensitive to noise and inconsistencies in the boundary data, and the accuracy of stereoscopy is affected by the ability of identifying the same structure in different images and by the separation angle between the view directions. As a consequence, for the same observational data, the 3D coronal magnetic fields computed with the two methods do not necessarily coincide. In an earlier work (Paper I) we extended our NLFFF optimization code by including stereoscopic constrains. The method was successfully tested with synthetic data, and within this work, we apply the newly developed code to a combined data set from SDO/HMI, SDO/AIA, and the two STEREO spacecraft. The extended method (called S-NLFFF) contains an additional term that monitors and minimizes the angle between the local magnetic field direction and the orientation of the 3D coronal loops reconstructed by stereoscopy. We find that when we prescribe the shape of the 3D stereoscopically reconstructed loops, the S-NLFFF method leads to a much better agreement between the modeled field and the stereoscopically reconstructed loops. We also find an appreciable decrease by a factor of two in the angle between the current and the magnetic field. This indicates the improved quality of the force-free solution obtained by S-NLFFF.

  12. Axial Current and Noether Charge

    CERN Document Server

    Mahato, Prasanta

    2012-01-01

    A decade ago, a Lagrangian density has been proposed by the author where only the local symmetries of the Lorentz subgroup of (A)ds group is retained. This formalism has been found to produce some results encompassing that of standard Einstein-Hilbert formalism. In the present article, the conserved axial vector matter currents, constructed in some earlier paper, have been found to be a result of Noether's theorem. PACS: 04.20.Fy, 04.20.Cv, 11.40.-q Keywords: Torsion, Axial Current, Noether's Theorem

  13. Relativistic RPA in axial symmetry

    CERN Document Server

    Arteaga, D Pena; 10.1103/PhysRevC.77.034317

    2009-01-01

    Covariant density functional theory, in the framework of self-consistent Relativistic Mean Field (RMF) and Relativistic Random Phase approximation (RPA), is for the first time applied to axially deformed nuclei. The fully self-consistent RMF+RRPA equations are posed for the case of axial symmetry and non-linear energy functionals, and solved with the help of a new parallel code. Formal properties of RPA theory are studied and special care is taken in order to validate the proper decoupling of spurious modes and their influence on the physical response. Sample applications to the magnetic and electric dipole transitions in $^{20}$Ne are presented and analyzed.

  14. A genome-wide association study identifies susceptibility loci for nonsyndromic sagittal craniosynostosis near BMP2 and within BBS9

    NARCIS (Netherlands)

    Justice, C.M.; Yagnik, G.; Kim, Y.; Peter, I.; Jabs, E.W.; Erazo, M.; Ye, X.; Ainehsazan, E.; Shi, L.; Cunningham, M.L.; Kimonis, V.; Roscioli, T.; Wall, S.A.; Wilkie, A.O.; Stoler, J.; Richtsmeier, J.T.; Heuze, Y.; Sanchez-Lara, P.A.; Buckley, M.F.; Druschel, C.M.; Mills, J.L.; Caggana, M.; Romitti, P.A.; Kay, D.M.; Senders, C.; Taub, P.J.; Klein, O.D.; Boggan, J.; Zwienenberg-Lee, M.; Naydenov, C.; Kim, J.; Wilson, A.F.; Boyadjiev, S.A.

    2012-01-01

    Sagittal craniosynostosis is the most common form of craniosynostosis, affecting approximately one in 5,000 newborns. We conducted, to our knowledge, the first genome-wide association study for nonsyndromic sagittal craniosynostosis (sNSC) using 130 non-Hispanic case-parent trios of European ancestr

  15. Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

    Indian Academy of Sciences (India)

    Milan Minarovjech; Milan Rybansky; Vojtech Rusin

    2000-09-01

    We present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of whitelight coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

  16. Gravitational forces and sagittal shape of the spine. Clinical estimation of their relations.

    Science.gov (United States)

    Legaye, J; Duval-Beaupere, G

    2008-12-01

    The sagittal morphology of the pelvis determines the amount of lordosis needed for each individual. The proper harmony of the sagittal spinal curves allows a stable balance, economical in terms of mechanical effects and muscular energy. A previous barycentremetrical laboratory study allowed us to demonstrate that the axis of gravity of the upper body segment was located behind the lumbar vertebrae and the femoral heads, thus ensuring economy and stability. The determination of the anatomical connection of the individual gravity is thus of primary importance for the evaluation of sagittal balance. Data for 42 patients without spinal pathology, previously evaluated by barycentremetry, were used to establish a predictive equation for the application point of the gravity at the level of the third lumbar vertebra (L3). This equation, using anthropometric and radiographic pelvic and spinal parameters, was integrated into a software program called Similibary. It was applied to the same 42 subjects. These results were compared in order to validate the method. No significant difference was observed between the two techniques. This easy-to-use tool allows a personalised evaluation of the sagittal balance of the spine, both through the evaluation of the harmonious relationship between the spinal curves and the pelvis, and through the location of gravity supported by the vertebral structures in L3.

  17. Long term stability of mandibular advancement procedures : bilateral sagittal split osteotomy versus distraction osteogenesis

    NARCIS (Netherlands)

    Baas, E. M.; Pijpe, J.; de Lange, J.

    2012-01-01

    The aim of this study was to compare the postoperative stability of the mandible after a bilateral lengthening procedure, either by bilateral sagittal split osteotomy (BSSO) or distraction osteogenesis (DO). All patients who underwent mandibular advancement surgery between March 2001 and June 2004 w

  18. Stability of mandibular advancement procedures : Bilateral sagittal split osteotomy versus distraction osteogenesis

    NARCIS (Netherlands)

    Vos, M. D.; Baas, E. M.; de lange, J.; Bierenbroodspot, F.

    2009-01-01

    The aim of this study was to compare the postoperative stability of the mandible after a bilateral lengthening procedure, either by bilateral sagittal split osteotomy (BSSO) or distraction osteogenesis (DOG). All patients who underwent mandibular advancement surgery between March 2001 and June 2004

  19. Sagittal alignment of the first metatarsophalangeal joint after arthrodesis for rheumatoid forefoot deformity.

    Science.gov (United States)

    Tanabe, Akihiko; Majima, Tokifumi; Onodera, Tomohiro; Sawaguchi, Naohiro; Watanabe, Takuya; Kasahara, Yasuhiko; Takahashi, Daisuke

    2013-01-01

    The present study assessed the midterm results of reconstruction for rheumatoid forefoot deformity with arthrodesis of the first metatarsophalangeal (MTP) joint, scarf osteotomy, resection arthroplasty of the metatarsal head of the lesser toes, and surgical repair of hammertoe deformity (arthrodesis of the proximal interphalangeal joint). Special focus was placed on the sagittal alignment of the first metatarsophalangeal joint after arthrodesis. We retrospectively evaluated the postoperative clinical outcomes and radiographic findings for 16 consecutive female patients (20 feet) with symptomatic rheumatoid forefoot deformities. The mean duration of follow-up was 7.9 (range 4 to 13) years. All first MTP joints and first metatarsal bones were fused successfully. The mean value of the American Orthopaedic Foot and Ankle Society and Japanese Society for Foot Surgery clinical scores significantly improved overall, except for 2 patients (10%), who complained of first toe pain at the final follow-up visit owing to sagittal misalignment of the fused first MTP joint. Sagittal alignment of the first metatarsal varies greatly because of the rheumatoid midfoot and hindfoot deformities. Therefore, inclination of the first metatarsal should be considered when determining the first MTP joint sagittal fusion angle.

  20. 3D analysis of condylar remodelling and skeletal relapse following bilateral sagittal split advancement osteotomies

    NARCIS (Netherlands)

    Xi, T.; Schreurs, R.; Loon, B. van; Koning, M.J. de; Berge, S.J.; Hoppenreijs, T.J.; Maal, T.J.J.

    2015-01-01

    A major concern in mandibular advancement surgery using bilateral sagittal split osteotomies (BSSO) is potential postoperative relapse. Although the role of postoperative changes in condylar morphology on skeletal relapse was reported in previous studies, no study so far has objectified the precise

  1. Anterior sagittal anorectoplasty: An alternative to posterior approach in management of congenital vestibular fistula

    Directory of Open Access Journals (Sweden)

    Man Mohan Harjai

    2013-01-01

    Full Text Available Background: Better exposure, possibility of extension if needed and precise placement of the anal canal within the external sphincter complex have made the posterior and anterior sagittal approaches more popular and established for the correction of anovestibular fistula. The mini posterior sagittal anorectoplasty (PSARP was the procedure of choice for female ARM at our center till date. As an alternative surgical option, we performed anterior sagittal anorectoplasty (ASARP in 15 cases of anovestibular fistula and compared them with 12 cases of vestibular fistula operated by PSARP technique. Patients and Methods: Fifteen female infants with vestibular fistula who had anterior sagittal anorectoplasty (ASARP procedure were reviewed. The procedure and its outcome were evaluated. Results : The manoeuvering during anesthesia and operative access were quite easier in ASARP compared to PSARP. Delineation of plane in ASARP between rectum and vagina was easier and clearer in comparison to PSARP. Rent occurred in the posterior vaginal wall in three cases of ASARP and two cases of PSARP. There were two cases of wound infection in each group. Three cases of PSARP group developed anal stenosis and constipation while one in the ASARP group developed constipation. Conclusion : Anesthesia and access in ASARP makes it an easier alternative option to PSARP in the management of anovestibular fistula in girls.

  2. INFLUENCE OF THE SAGITTAL BALANCE ON THE CLINICAL OUTCOME IN SPINAL FUSION

    Directory of Open Access Journals (Sweden)

    Marcela Almeida Campos Coutinho

    2016-03-01

    Full Text Available ABSTRACT Objective: Evaluates which radiographic parameters of the sagittal and spinopelvic balance influence the clinical and functional outcomes of a sample of patients undergoing spinal fusion. Methods: We studied 32 patients who underwent spinal fusion. Radiographs of the total spine were obtained from all patients. The clinical and functional parameters studied were analysis of pain by visual analogic scale (VAS and Oswestry and SRS-30 questionnaires. We analyzed the correlation between the clinical and functional parameters and radiographic parameters of the sagittal and spinopelvic balance. Results: There was no significant correlation between parameters pelvic incidence (PI, pelvic tilt (PT, lumbar lordosis (LL and difference between PI and LL (PI-LL and clinical parameters (p > 0.05 and r <0.2. Significant correlation were identified only between Sagittal Vertical Axis (SVA and Satisfaction with Treatment domain of SRS-30 (r = 0.402 e p = 0.023 and between thoracic kyphosis (TK and the total SRS-30 (r = 0.419 and p = 0.017. Conclusions: According to the study results, it was not possible to precisely characterize the role of the parameters of the sagittal and spinopelvic balance in the post-operative analysis of the clinical outcome of spinal fusion. There was a significant correlation only between SVA and the Satisfaction with Treatment domain of SRS-30 and between TK and total SRS-30.

  3. Cervical spine sagittal alignment variations following posterior spinal fusion and instrumentation for adolescent idiopathic scoliosis.

    Science.gov (United States)

    Canavese, Federico; Turcot, Katia; De Rosa, Vincenzo; de Coulon, Geraldo; Kaelin, André

    2011-07-01

    The aim of this study is to quantify the changes in the sagittal alignment of the cervical spine in patients with adolescent idiopathic scoliosis following posterior spinal fusion. Patients eligible for study inclusion included those with a diagnosis of mainly thoracic adolescent idiopathic scoliosis treated by means of posterior multisegmented hook and screw instrumentation. Pre and post-operative anterior-posterior and lateral radiographs of the entire spine were reviewed to assess the changes of cervical sagittal alignment. Thirty-two patients (3 boys, 29 girls) met the inclusion criteria for the study. The average pre-operative cervical sagittal alignment (CSA) was 4.0° ± 12.3° (range -30° to 40°) of lordosis. Postoperatively, the average CSA was 1.7° ± 11.4° (range -24° to 30°). After surgery, it was less than 20° in 27 patients (84.4%) and between 20° and 40° in 5 patients (15.6%). The results of the present study suggest that even if rod precontouring is performed and postoperative thoracic sagittal alignment is restored, improved or remains unchanged after significant correction of the deformity on the frontal plane, the inherent rigidity of the cervical spine limits changes in the CSA as the cervical spine becomes rigid over time.

  4. Magnetic resonance imaging of vascular compression in trigeminal neuralgia and hemifacial spasms; The efficacy of oblique sagittal view

    Energy Technology Data Exchange (ETDEWEB)

    Nagaseki, Yoshishige; Horikoshi, Tohru; Omata, Tomohiro; Sugita, Masao; Nukui, Hideaki; Sakamoto, Hajime; Kumagai, Hiroshi (Yamanashi Medical College, Tamaho (Japan)); Sasaki, Hideo; Tsuji, Reizou

    1991-06-01

    We show how neurosurgical planning can benefit from the better visualization of the precise vascular compression of the nerve provided by the oblique-sagittal and gradient-echo method (OS-GR image) using magnetic resonance images (MRI). The scans of 3 patients with trigeminal neuralgia (TN) and of 15 with hemifacial spasm (HFS) were analyzed for the presence and appearance of the vascular compression of the nerves. Imaging sequences consisted of an OS-GR image (TR/TE: 200/20, 3-mm-thick slice) cut along each nerve shown by the axial view, which was scanned at the angle of 105 degrees taken between the dorsal line of the brain stem and the line corresponding to the pontomedullary junction. In the OS-GR images of the TN's, the vascular compressions of the root entry zone (REZ) of the trigeminal nerve were well visualized as high-intensity lines in the 2 cases whose vessels were confirmed intraoperatively. In the other case, with atypical facial pain, vascular compression was confirmed at the rostral distal site on the fifth nerve, apart from the REZ. In the 15 cases of HFS, twelve OS-GR images (80%) demonstrated vascular compressions at the REZ of the facial nerves from the direction of the caudoventral side. During the surgery for these 12 cases, in 11 cases (excepting the 1 case whose facial nerve was not compressed by any vessels), vascular compressions were confirmed corresponding to the findings of the OS-GR images. Among the 10 OS-GR images on the non-affected side, two false-positive findings were visualized. It is concluded that OS-GR images obtained by means of MRI may serve as a useful planning aid prior to microvascular decompression for cases of TN and HFS. (author).

  5. The effect of single-level, total disc arthroplasty on sagittal balance parameters: a prospective study.

    Science.gov (United States)

    Le Huec, Jc; Basso, Y; Mathews, H; Mehbod, A; Aunoble, S; Friesem, T; Zdeblick, T

    2005-06-01

    A prospective radiographic study of the influence of total disc replacement on spinal sagittal balance. The goal of this study was to prospectively determine the effect of a single-level, total disc replacement on the sagittal balance of the spine, especially on sacral tilt (ST), pelvic tilt (PT), and lumbar lordosis. It has been shown that lumbar fusion may deleteriously alter the sagittal balance of the spine, including a decrease in the ST and lumbar lordosis. Clinically, postfusion pain has been shown to be significantly related to a decreased ST, increased PT, and decreased lumbar lordosis, independent of other factors such as pseudoarthrosis. To our knowledge, the influence of total disc replacement on spinal sagittal balance has not yet been reported in the literature. This is a prospective study of 35 patients who received a single level disc replacement using the Maverick Total Disc Arthroplasty system (Medtronic Sofamor Danek, Memphis, Tennessee) by a single surgeon at one institution from March 2002 to September 2003. The preoperative and postoperative radiographic evaluation included standing anteroposterior and lateral full spine films that included the femoral heads. The parameters studied were ST, PT, global and segmental lordosis, and global kyphosis. The average age of the 35 patients studied was 44.3 years (range 35-57). There were 18 females and 17 males. The disc arthroplasty was performed at the L4-L5 level in 19 patients and at the L5-S1 level in 16 patients. The average follow-up was 14 months (range 6-22 months). The preoperative values of global lordosis, ST, and PT were 51.5 degrees , 37.8 degrees , 16.9 degrees and, at last follow-up, they were 51.4 degrees , 37.4 degrees , and 17.5 degrees , respectively. These changes were not significantly different. When the groups were separated according to the level operated, there was still no statistical difference with regard to the overall lordosis, ST, PT or kyphosis from pre- to postoperative

  6. Axial structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner

    2002-01-01

    We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.

  7. Thermophoresis of Axially Symmetric Bodies

    Science.gov (United States)

    2007-11-02

    Sweden Abstract. Thermophoresis of axially symmetric bodies is investigated to first order in the Knudsen-mimber, Kn. The study is made in the limit...derived. Asymptotic solutions are studied. INTRODUCTION Thermophoresis as a phenomenon has been known for a long time, and several authors have approached

  8. Comparison of accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions: An exvivo study

    Directory of Open Access Journals (Sweden)

    Asieh Zamani Naser

    2010-01-01

    Full Text Available Background: Radiographic examination of TMJ is indicated when there are clinical signs of pathological conditions, mainly bone changes that may influence the diagnosis and treatment planning. The purpose of this study was to evaluate and to compare the validity and diagnostic accuracy of uncorrected and corrected sagittal tomographic images in the detection of simulated mandibular condyle erosions. Methods : Simulated lesions were created in 10 dry mandibles using a dental round bur. Using uncorrected and corrected sagittal tomography techniques, mandibular condyles were imaged by a Cranex Tome X-ray unit before and after creating the lesions. The uncorrected and corrected tomography images were examined by two independent observers for absence or presence of a lesion. The accuracy for detecting mandibular condyle lesions was expressed as sensitivity, specificity, and validity values. Differences between the two radiographic modalities were tested by Wilcoxon for paired data tests. Inter-observer agreement was determined by Cohen′s Kappa. Results: The sensitivity, specificity and validity were 45%, 85% and 30% in uncorrected sagittal tomographic images, respectively, and 70%, 92.5% and 60% in corrected sagittal tomographic images, respectively. There was a significant statistical difference between the accuracy of uncorrected and corrected sagittal tomography in detection of mandibular condyle erosions (P = 0.016. The inter-observer agreement was slight for uncorrected sagittal tomography and moderate for corrected sagittal tomography. Conclusion: The accuracy of corrected sagittal tomography is significantly higher than that of uncorrected sagittal tomography. Therefore, corrected sagittal tomography seems to be a better modality in detection of mandibular condyle erosions.

  9. The Coronal Global Evolutionary Model (CGEM)

    Science.gov (United States)

    Fisher, George H.; DeRosa, M. L.; Hoeksema, J. T.

    2013-07-01

    The Coronal Global Evolutionary Model, or CGEM, is a collaborative effort from the UC Berkeley Space Sciences Laboratory (SSL), Stanford University, and Lockheed-Martin. In work that led up to the selection of this project, the team demonstrated its capability to use sequences of vector magnetograms and Dopplergrams from the Helioseismic and Magnetic Imager (HMI) instrument aboard the SDO to drive a magnetofrictional (MF) model of the coronal magnetic field in AR 11158, which produced an X2.2 flare. We will implement this MF model in spherical coordinates to enable real-time, long-term modeling of the non-potential coronal magnetic field, both globally and for individual active region (ARs). The model's Earth-facing hemisphere will be driven using electric fields derived from the observed evolution of photospheric line-of-sight magnetic fields and electric currents. Far-side data inputs will be from an existing flux transport code, combined with HMI far-side observations of new active regions, with empirical parametrizations of orientation and flux. Because this model includes large-scale coronal electric currents, it is a substantial improvement over existing real-time global coronal models, which assume potential fields. Data products available from the model will include: 1) the evolving photospheric electric field, Poynting flux, and helicity flux; 2) estimates of coronal free energy and non-potential geometry and topology; 3) initial and time-dependent boundary conditions for MHD modeling of active regions; and 4) time-dependent boundary conditions and flux tube expansion factors for MHD and empirical solar wind models. Unstable configurations found from MF models will be dynamically evolved with local and global MHD codes. Modules used to derive surface electric fields from magnetic evolution will be incorporated into the SDO/HMI data pipeline, and data products will be distributed through the Joint Science Operations Center (JSOC) and directly to space

  10. Reconnection and Spire Drift in Coronal Jets

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Falconer, David

    2015-04-01

    It is observed that there are two morphologically-different kinds of X-ray/EUV jets in coronal holes: standard jets and blowout jets. In both kinds: (1) in the base of the jet there is closed magnetic field that has one foot in flux of polarity opposite that of the ambient open field of the coronal hole, and (2) in coronal X-ray/EUV images of the jet there is typically a bright nodule at the edge of the base. In the conventional scenario for jets of either kind, the bright nodule is a compact flare arcade, the downward product of interchange reconnection of closed field in the base with impacted ambient open field, and the upper product of this reconnection is the jet-outflow spire. It is also observed that in most jets of either kind the spire drifts sideways away from the bright nodule. We present the observed bright nodule and spire drift in an example standard jet and in two example blowout jets. With cartoons of the magnetic field and its reconnection in jets, we point out: (1) if the bright nodule is a compact flare arcade made by interchange reconnection, then the spire should drift toward the bright nodule, and (2) if the bright nodule is instead a compact flare arcade made, as in a filament-eruption flare, by internal reconnection of the legs of the erupting sheared-field core of a lobe of the closed field in the base, then the spire, made by the interchange reconnection that is driven on the outside of that lobe by the lobe’s internal convulsion, should drift away from the bright nodule. Therefore, from the observation that the spire usually drifts away from the bright nodule, we infer: (1) in X-ray/EUV jets of either kind in coronal holes the interchange reconnection that generates the jet-outflow spire usually does not make the bright nodule; instead, the bright nodule is made by reconnection inside erupting closed field in the base, as in a filament eruption, the eruption being either a confined eruption for a standard jet or a blowout eruption (as

  11. Sagittal synostosis in X-linked hypophosphatemic rickets and related diseases

    Energy Technology Data Exchange (ETDEWEB)

    Currarino, Guido [Texas Scottish Rite Hospital, Department of Radiology, Dallas, TX (United States)

    2007-08-15

    The recent observations of two new cases of X-linked hypophosphatemic rickets associated with premature closure of the sagittal suture prompted a review of similar cases seen in this institution. To review the clinical records and skull radiographs of 28 children with hypophosphatemic rickets in order to investigate the frequency and type of craniosynostosis and other cranial vault changes seen in these conditions and to review the literature for relevant findings. Clinical and imaging records were reviewed on 28 patients with hypophosphatemic rickets, all younger than 18 years. Most patients had X-linked hypophosphatemic rickets and a few had autosomal-dominant hypophosphatemic rickets or were non-familial cases. Of the 28 patients, 13 had sagittal synostosis. Dolichocephaly was present in ten patients. The configuration of the cranial vault in some of these ten patients with dolichocephaly varied somewhat from that seen in nonsyndromic sagittal synostosis. In one patient, a Chiari I malformation was demonstrated by MRI. In another patient with increased intracranial pressure the sagittal suture closure was associated with lambdoidal synostosis. Dolichocephaly was not present in three patients, suggesting that the synostosis started later than in the other patients, probably in the second year of life, a period of slower brain growth than in the first year. The two patients in this group of three showed thickening and sclerosis of the cranial vault of uncertain etiology. There is an increased risk of sagittal synostosis in hypophosphatemic rickets and related diseases in children. The appearance of the cranial vault in this type of synostosis can vary from that seen in nonsyndromic synostosis. In this setting, careful clinical and imaging follow-up is warranted. (orig.)

  12. Solar coronal observations at high frequencies

    CERN Document Server

    Katsiyannis, A C; Phillips, K J H; Williams, D R; Keenan, F P

    2001-01-01

    The Solar Eclipse Coronal Imaging System (SECIS) is a simple and extremely fast, high-resolution imaging instrument designed for studies of the solar corona. Light from the corona (during, for example, a total solar eclipse) is reflected off a heliostat and passes via a Schmidt-Cassegrain telescope and beam splitter to two CCD cameras capable of imaging at 60 frames a second. The cameras are attached via SCSI connections to a purpose-built PC that acts as the data acquisition and storage system. Each optical channel has a different filter allowing observations of the same events in both white light and in the green line (Fe XIV at 5303 A). Wavelet analysis of the stabilized images has revealed high frequency oscillations which may make a significant contribution on the coronal heating process. In this presentation we give an outline of the instrument and its future development.

  13. Selamento coronário em Endodontia

    OpenAIRE

    Oliveira, Rui Pedro Barra de Sá

    2016-01-01

    Introdução: A Endodontia é a especialidade da Medicina Dentária responsável pelo estudo e tratamento da câmara pulpar, de todo o sistema de canais radiculares e dos tecidos periapicais, bem como das doenças que os afetam. O selamento da porção coronária dos dentes alvo de tratamento endodôntico apresenta-se como um critério determinante no sucesso ou insucesso do tratamento. São vários os fatores que podem proporcionar um correto selamento coronário evitando assim a microinfiltração de ...

  14. Magnetic Topology of Coronal Hole Linkages

    CERN Document Server

    Titov, V S; Linker, J A; Lionello, R; Antiochos, S K

    2010-01-01

    In recent work, Antiochos and coworkers argued that the boundary between the open and closed field regions on the Sun can be extremely complex with narrow corridors of open flux connecting seemingly disconnected coronal holes from the main polar holes, and that these corridors may be the sources of the slow solar wind. We examine, in detail, the topology of such magnetic configurations using an analytical source surface model that allows for analysis of the field with arbitrary resolution. Our analysis reveals three important new results: First, a coronal hole boundary can join stably to the separatrix boundary of a parasitic polarity region. Second, a single parasitic polarity region can produce multiple null points in the corona and, more important, separator lines connecting these points. It is known that such topologies are extremely favorable for magnetic reconnection, because they allow this process to occur over the entire length of the separators rather than being confined to a small region around the...

  15. Damped transverse oscillations of interacting coronal loops

    CERN Document Server

    Soler, Roberto

    2015-01-01

    Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations compared to those of an isolated loop. Here we theoretically investigate resonantly damped transverse oscillations of interacting non-uniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. ...

  16. Solar Coronal Jets: Observations, Theory, and Modeling

    CERN Document Server

    Raouafi, N E; Pariat, E; Young, P R; Sterling, A C; Savcheva, A; Shimojo, M; Moreno-Insertis, F; DeVore, C R; Archontis, V; Török, T; Mason, H; Curdt, W; Meyer, K; Dalmasse, K; Matsui, Y

    2016-01-01

    Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients close or at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broad range of solar-heliospheric problems.

  17. Chemical Fractionation and Abundances in Coronal Plasma

    CERN Document Server

    Drake, J J

    2003-01-01

    Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer atmospheres of stars have demonstrated that these environments are subject to chemical fractionation in which the abundances of elements can be enhanced and depleted by an order of magnitude or more. These coronal abundance anomalies are discussed and some of the physical mechanisms that might be responsible for producing them are examined. It is argued that coronal abundances can provide important new diagnostics on physical processes at work in solar and stellar coronae. It seems likely that other hot astrophysical plasmas will be subject to similar effects.

  18. Microflares as Possible Sources for Coronal Heating

    Indian Academy of Sciences (India)

    Meera Gupta; Rajmal Jain; Jayshree Trivedi; A. P. Mishra

    2008-03-01

    We present a preliminary study of 27 microflares observed by Solar X-ray Spectrometer (SOXS) mission during July 2003 to August 2006. We found that all 27 microflares show the Fe-line feature peaking around 6.7 keV, which is an indicator of the presence of coronal plasma temperature ≥ 9 MK. On the other hand, the spectra of microflares showhybrid model of thermal and non-thermal emission, which further supports them as possible sources of coronal heating. Our results based on the analysis show that the energy relapsed by the microflares is good enough for heating of the active corona. We discuss our results in the light of the hybrid model of microflares production.

  19. Optimization of axial blowers. Optimierung von Axial-Ventilatoren

    Energy Technology Data Exchange (ETDEWEB)

    Bolte, W.

    1992-08-01

    For the optimum possible design of axial blowers, trials are evaluated in the article, which are based on the grid profile examined by N. Scholz. The computation for the pressure number and the primary degree of efficiency are shown as well as the evaluation of the effect of the Reynolds and mach number on the degree of efficiency and determination of the secondary losses. In a final example, the dimensions of a blower are computed from the data determined during the trials. (orig.).

  20. Bridging the Gap between Coronal and Non-Coronal Evolved Stars

    Science.gov (United States)

    Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.

    2017-01-01

    The Hubble Space Telescope (HST) Treasury Program "Advanced Spectral Library (ASTRAL)" enables investigations of a broad range of problems including the character and dynamics of the wind and chromosphere of cool stars. This paper presents an investigation of the change in spectral characteristics when transitioning from the cool non-coronal objects with fluorescent emission spectra from the iron group elements, molecular hydrogen, and carbon monoxide to the warmer stars on the blue side of the Linsky-Haish dividing line in the HR diagram. These warmer objects exhibit chromospheric emission from significantly hotter environments in addition to coronal signatures, while the hybrid stars overlap in the HR-diagram with some of the non-coronal objects and share many spectral characteristics but show differences in the wind properties. We show how the wind, fluorescent features, and hot stellar signatures dramatically change with spectral class by comparing the already analyzed non-coronal objects (Alpha Ori, Gamma Cru) with the hybrid stars (Gamma Dra, Beta Gem and Alpha Aqr) and the coronal object Beta Dra. We aim to gain understanding of the physical processes in these objects' outer atmospheres and their evolutionary tracks.

  1. Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

    CERN Document Server

    Mason, James Paul; Webb, David F; Thompson, Barbara J; Colaninno, Robin C; Vourlidas, Angelos

    2016-01-01

    Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar flare, as is often the case, the flare component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37 dimming events identified during two separate two-week periods in 2011, plus an event on 2010 August 7 analyzed in a previous paper, to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to t...

  2. Coronal Mass Ejections of Solar Cycle 23

    Indian Academy of Sciences (India)

    Nat Gopalswamy

    2006-06-01

    I summarize the statistical, physical, and morphological properties of coronal mass ejections (CMEs) of solar cycle 23, as observed by the Solar and Heliospheric Observatory (SOHO) mission. The SOHO data is by far the most extensive data, which made it possible to fully establish the properties of CMEs as a phenomenon of utmost importance to Sun–Earth connection as well as to the heliosphere. I also discuss various subsets of CMEs that are of primary importance for their impact on Earth.

  3. Coronal Plumes in the Fast Solar Wind

    Science.gov (United States)

    Velli, Marco; Lionello, Roberto; Linker, Jon A.; Mikic, Zoran

    2011-01-01

    The expansion of a coronal hole filled with a discrete number of higher density coronal plumes is simulated using a time-dependent two-dimensional code. A solar wind model including an exponential coronal heating function and a flux of Alfven waves propagating both inside and outside the structures is taken as a basic state. Different plasma plume profiles are obtained by using different scale heights for the heating rates. Remote sensing and solar wind in situ observations are used to constrain the parameter range of the study. Time dependence due to plume ignition and disappearance is also discussed. Velocity differences of the order of approximately 50 km/s, such as those found in microstreams in the high-speed solar wind, may be easily explained by slightly different heat deposition profiles in different plumes. Statistical pressure balance in the fast wind data may be masked by the large variety of body and surface waves which the higher density filaments may carry, so the absence of pressure balance in the microstreams should not rule out their interpretation as the extension of coronal plumes into interplanetary space. Mixing of plume-interplume material via the Kelvin-Helmholtz instability seems to be possible within the parameter ranges of the models defined here, only at large di stances from the Sun, beyond 0.2-0.3 AU. Plasma and composition measurements in the inner heliosphere, such as those which will become available with Solar Orbiter and Solar Probe Plus, should therefore definitely be able to identify plume remnants in the solar wind.

  4. Interchange Reconnection and Coronal Hole Dynamics

    Science.gov (United States)

    2010-05-01

    calculate the time-dependent dynamics of coronal hole boundaries rigorously and test our conjectures. We describe below our numerical simulations of...radiation and thermal conduction are needed in order to test such a model. It is tempting to conjecture that this process of releasing the closed-field... HTP , TR&T, and SR&T Programs, and has benefited greatly from the authors’ participation in the NASA TR&T focused science team on the solar

  5. Towards a Data-Optimized Coronal Magnetic Field Model (DOC-FM): Simulating Flux Ropes with the Flux Rope Insertion Method

    Science.gov (United States)

    Dalmasse, K.; DeLuca, E. E.; Savcheva, A. S.; Gibson, S. E.; Fan, Y.

    2015-12-01

    Knowledge of the 3D magnetic filed structure at the time of major solar eruptions is vital or understanding of the space weather effects of these eruptions. Multiple data-constrained techniques that reconstruct the 3D coronal field based on photospheric magnetograms have been used to achieve this goal. In particular, we have used the flux rope insertion method to obtain the coronal magnetic field of multiple regions containing flux ropes or sheared arcades based on line-of-sight magnetograms and X-ray and EUV observations of coronal loops. For the purpose of developing statistical measures of the goodness of fit of these models to the observations, here we present our modeling of flux ropes based on synthetic magnetograms obtained from Fan & Gibson emerging flux rope simulation. The goal is to reproduce the flux rope structure from a given time step of the MHD simulations based only on the photospheric magnetogram and synthetic forward modeled coronal emission obtained from the same step of the MHD simulation. For this purpose we create a large grid of models with the flux rope insertion method with different combinations of axial and poloidal flux, which give us different morphology of the flux rope. Then we compare the synthetic coronal emission with the shape of the current distribution and field lines from the models to come up with a best fit. This fit is then tested using the statistical methods developed by our team.

  6. Coronal Structure of Low-Mass Stars

    CERN Document Server

    Lang, Pauline; Donati, Jean-Francois; Morin, Julien; Vidotto, Aline

    2012-01-01

    We investigate the change in stellar magnetic topology across the fully-convective boundary and its effects on coronal properties. We consider both the magnitude of the open flux that influences angular momentum loss in the stellar wind and X-ray emission measure. We use reconstructed maps of the radial magnetic field at the stellar surface and the potential-field source surface method to extrapolate a 3D coronal magnetic field for a sample of early-to-mid M dwarfs. During the magnetic reconstruction process it is possible to force a solution towards field geometries that are symmetric or antisymmetric about the equator but we demonstrate that this has only a modest impact on the coronal tracers mentioned above. We find that the dipole component of the field, which governs the large-scale structure, becomes increasingly strong as the stellar mass decreases, while the magnitude of the open (wind-bearing) magnetic flux is proportional to the magnitude of the reconstructed magnetic flux. By assuming a hydrostati...

  7. A Mechanism for Coronal Hole Jets

    CERN Document Server

    Mueller, D A N

    2008-01-01

    Bald patches are magnetic topologies in which the magnetic field is concave up over part of a photospheric polarity inversion line. A bald patch topology is believed to be the essential ingredient for filament channels and is often found in extrapolations of the observed photospheric field. Using an analytic source-surface model to calculate the magnetic topology of a small bipolar region embedded in a global magnetic dipole field, we demonstrate that although common in closed-field regions close to the solar equator, bald patches are unlikely to occur in the open-field topology of a coronal hole. Our results give rise to the following question: What happens to a bald patch topology when the surrounding field lines open up? This would be the case when a bald patch moves into a coronal hole, or when a coronal hole forms in an area that encompasses a bald patch. Our magnetostatic models show that, in this case, the bald patch topology almost invariably transforms into a null point topology with a spine and a fa...

  8. The formation of an equatorial coronal hole

    Science.gov (United States)

    Yang, Liheng; Jiang, Yunchun; Zhang, Jun

    2010-02-01

    The formation of an equatorial coronal hole (CH) from 2006 January 9 to 12 was simultaneously observed by GOES-12/SXI, SOHO/EIT and SOHO/MDI instruments. The varieties of soft X-ray and EUV brightness, coronal temperature, and total magnetic flux in the CH were examined and compared with that of a quiet-sun (QS) region nearby. The following results are obtained. (1) A preexisting dark lane appeared on the location of the followed CH and was reinforced by three enhanced networks. (2) The CH gradually formed in about 81 hours and was predominated by positive magnetic flux. (3) During the formation, the soft X-ray and EUV brightness, coronal temperature, and total magnetic flux obviously decreased in the CH, but were almost no change in the QS region. The decrease of the total magnetic flux may be the result of magnetic reconnection between the open and closed magnetic lines, probably indicating the physical mechanism for the birth of the CH.

  9. Propagating magnetohydrodynamics waves in coronal loops.

    Science.gov (United States)

    De Moortel, I

    2006-02-15

    High cadence Transition Region and Coronal Explorer (TRACE) observations show that outward propagating intensity disturbances are a common feature in large, quiescent coronal loops, close to active regions. An overview is given of measured parameters of such longitudinal oscillations in coronal loops. The observed oscillations are interpreted as propagating slow magnetoacoustic waves and are unlikely to be flare-driven. A strong correlation, between the loop position and the periodicity of the oscillations, provides evidence that the underlying oscillations can propagate through the transition region and into the corona. Both a one- and a two-dimensional theoretical model of slow magnetoacoustic waves are presented to explain the very short observed damping lengths. The results of these numerical simulations are compared with the TRACE observations and show that a combination of the area divergence and thermal conduction agrees well with the observed amplitude decay. Additionally, the usefulness of wavelet analysis is discussed, showing that care has to be taken when interpreting the results of wavelet analysis, and a good knowledge of all possible factors that might influence or distort the results is a necessity.

  10. Coronal Heating Observed with Hi-C

    Science.gov (United States)

    Winebarger, Amy R.

    2013-01-01

    The recent launch of the High-Resolution Coronal Imager (Hi-C) as a sounding rocket has offered a new, different view of the Sun. With approx 0.3" resolution and 5 second cadence, Hi-C reveals dynamic, small-scale structure within a complicated active region, including coronal braiding, reconnection regions, Alfven waves, and flows along active region fans. By combining the Hi-C data with other available data, we have compiled a rich data set that can be used to address many outstanding questions in solar physics. Though the Hi-C rocket flight was short (only 5 minutes), the added insight of the small-scale structure gained from the Hi-C data allows us to look at this active region and other active regions with new understanding. In this talk, I will review the first results from the Hi-C sounding rocket and discuss the impact of these results on the coronal heating problem.

  11. Dynamics of Coronal-Hole Boundaries

    CERN Document Server

    Higginson, A K; DeVore, C R; Wyper, P F; Zurbuchen, T H

    2016-01-01

    Remote and in-situ observations suggest that the slow solar wind consists of plasma from the hot, closed-field corona that is released onto open magnetic field lines. The Separatrix-Web (S-Web) theory for the slow wind proposes that photospheric motions, at the scale of supergranules, are responsible for generating dynamics at coronal-hole boundaries, which result in the inferred necessary transfer of plasma from closed to open field lines. We use 3D magnetohydrodynamic (MHD) simulations to determine the effect of photospheric flows on the open and closed magnetic flux of a model corona with a dipole magnetic field and an isothermal solar wind. We find that a supergranular-scale photospheric motion at the boundary between the coronal hole and helmet streamer results in prolific and efficient interchange reconnection between open and closed flux. This reconnection acts to smooth the large- and small-scale structure introduced by the photospheric flows. Magnetic flux near the coronal-hole boundary experiences m...

  12. The Lower Chromosphere in a Coronal Hole

    Science.gov (United States)

    Teplitskaya, R. B.; Turova, I. P.; Ozhogina, O. A.

    2007-07-01

    We study the Ca ii K, H, and λ 849.8 nm line profiles in two regions of the quiet Sun, one being located in the extensive low-latitude coronal hole observed on 3 through 5 August 2003, and the other being located outside the coronal hole. Comparison of the profiles was carried out separately for cells and cell boundaries of the chromospheric network. Our principal result is that space- and time-averaged profiles of the central self-reversal in the coronal hole sites differ from those outside of the hole: Intensities of the K3 and H3 central depressions are increased in the cells but are unchanged in the network; the height of the K2 peaks is reduced in the cells and particularly in the network; the central self-reversal asymmetry is intensified in the network. Distinctions appear at a high confidence level. Line wings as well as average characteristics of the infrared line remain practically unchanged. We discuss probable causes for this behavior of the lower chromosphere lines.

  13. Characteristics of polar coronal hole jets

    CERN Document Server

    Chandrashekhar, K; Banerjee, D; Gupta, G R; Teriaca, L

    2013-01-01

    High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be $\\approx$ 27 km s$^{-1}$. The average outward speed of the first jet is $\\approx 171$ km s$^{-1}$, well below the escape speed, hence if simple ballistic motio...

  14. View of the Axial Field Spectrometer

    CERN Multimedia

    1980-01-01

    The Axial Field Spectrometer, with the vertical uranium/scintillator calorimeter and the central drift chamber retracted for service. One coil of the Open Axial Field Magnet is just visible to the right.

  15. Eyecciones coronales de masa observadas en cuadratura exhibiendo sus perspectivas axial y lateral

    Science.gov (United States)

    Cabello, I.; Cremades, H.; Balmaceda, L.; Dohmen, I.

    2016-08-01

    Observations from different viewpoints provided by STEREO and SOHO allow us to simultaneously study the lateral and axial perspectives of a given coronal mass ejection. Following the exhaustive analysis of a case study, this work focuses on the analysis of similar events which exhibit the two perspectives as seen by the different instruments. Angular width estimates for both, the lateral and axial directions obtained in an indirect way, i.e. applying the graduated cylindrical shell model, allowed us to obtain a ratio / in agreement with results previously obtained in a direct way, i.e. when and were measured either separately for different events or when they were estimated for a single event from multi-point observations.

  16. The acceleration of electrons at a spherical coronal shock in a streamer-like coronal field

    Science.gov (United States)

    Kong, Xiangliang; Chen, Yao; Guo, Fan

    2016-03-01

    We study the effect of large-scale coronal magnetic field on the electron acceleration at a spherical coronal shock using a test-particle method. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. It shows that the closed field plays the role of a trapping agency of shock-accelerated electrons, allowing for repetitive reflection and acceleration, therefore can greatly enhance the shock-electron acceleration efficiency. It is found that, with an ad hoc pitch-angle scattering, electron injected in the open field at the shock flank can be accelerated to high energies as well. In addition, if the shock is faster or stronger, a relatively harder electron energy spectrum and a larger maximum energy can be achieved.

  17. Standing Slow-Mode Waves in Hot Coronal Loops: Observations, Modeling, and Coronal Seismology

    CERN Document Server

    Wang, Tongjiang

    2010-01-01

    Strongly damped Doppler shift oscillations are observed frequently associated with flarelike events in hot coronal loops. In this paper, a review of the observed properties and the theoretical modeling is presented. Statistical measurements of physical parameters (period, decay time, and amplitude) have been obtained based on a large number of events observed by SOHO/SUMER and Yohkoh/BCS. Several pieces of evidence are found to support their interpretation in terms of the fundamental standing longitudinal slow mode. The high excitation rate of these oscillations in small- or micro-flares suggest that the slow mode waves are a natural response of the coronal plasma to impulsive heating in closed magnetic structure. The strong damping and the rapid excitation of the observed waves are two major aspects of the waves that are poorly understood, and are the main subject of theoretical modeling. The slow waves are found mainly damped by thermal conduction and viscosity in hot coronal loops. The mode coupling seems ...

  18. A unified theory of electrodynamic coupling in coronal magnetic loops - The coronal heating problem

    Science.gov (United States)

    Ionson, J. A.

    1984-01-01

    The coronal heating problem is studied, and it is demonstrated that Ionson's (1982) LRC approach results in a unified theory of coronal heating which unveils a variety of new heating mechanisms and which links together previously proposed mechanisms. Ionson's LRC equation is rederived, focusing on various aspects that were not clarified in the original article and incorporating new processes that were neglected. A parameterized heating rate is obtained. It is shown that Alfvenic surface wave heating, stochastic magnetic pumping, resonant electrodynamic heating, and dynamical dissipation emerge as special cases of a much more general formalism. This generalized theory is applied to solar coronal loops and it is found that active region and large scale loops are underdamped systems. Young active region loops and (possibly) bright points are found to be overdamped systems.

  19. Axial Spondyloarthritis: An Evolving Concept

    Directory of Open Access Journals (Sweden)

    Nelly Ziadé

    2015-07-01

    Full Text Available Axial spondyloarthritis (AxSpA is the prototype of a family of inter-related yet heterogeneous diseases sharing common clinical and genetic manifestations: the spondyloarthritides (SpAs. The condition mainly affects the sacroiliac joints and axial skeleton, and has a clear classification scheme, wider epidemiological data, and distinct therapeutic guidelines when compared with other SpAs. However, the concept of AxSpA has not been immutable over time and has evolved tremendously on many levels over the past decades. This review identifies the evolution of the AxSpA concept at two levels. First, at the level of classification, the old classifications and rationales leading to the current Assessment of SpondyloArthritis international Society (ASAS classification are reviewed, and the advantages and drawbacks are discussed. Second, at the therapeutic level, current and future treatments are described and treatment strategies are discussed.

  20. [Axial spondyloarthritis and ankylosing spondylitis].

    Science.gov (United States)

    Nordström, Dan; Kauppi, Markku

    2010-01-01

    Current classification criteria for ankylosing spondylitis do not allow diagnosis before radiographic changes are visible in sacroiliacal joints. The the new axial spondyloarthropathy (SpA) criteria include axial SpA without radiographic changes as well as established ankylosing spondylitis, recognizing them as a continuum of the same disease. This is of major importance as the burden of early SpA is comparable to that of later stage disease. Diagnosis relies on inflammatory MRI findings which is the most significant change compared to earlier criteria. Emerging data on the efficacy of tumor necrosis factor (TNF) alpha blocking therapies already in early but also in established disease have given new promising alternatives for treatment of this often very cumbersome disease, that rarely responds to classic DMARDs.

  1. Segmentation of Coronal Holes Using Active Contours Without Edges

    CERN Document Server

    Boucheron, L E; McAteer, R T J

    2016-01-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. As the source of the fast solar wind, the detection and characterization of these regions is important for both testing theories of their formation and evolution and from a space weather perspective. Coronal holes are detected in full disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind ...

  2. Volar morphology of the distal radius in axial planes: a quantitative analysis.

    Science.gov (United States)

    Oura, Keiichiro; Oka, Kunihiro; Kawanishi, Yohei; Sugamoto, Kazuomi; Yoshikawa, Hideki; Murase, Tsuyoshi

    2015-04-01

    To investigate the cause of rupture of the flexor pollicis longus (FPL) after volar plate fixation of distal radius fractures, previous studies have examined the shape of the distal radius in the sagittal plane or in the lateral view. However, there are no reports on the anatomical shape of the volar surface concavity of the distal radius in the axial plane. We hypothesized that this concavity might contribute to the mismatch between the plate and the surface of the radius. To test this hypothesis, we constructed three-dimensional models of the radius and FPL based on computed tomography scans of 70 normal forearms. We analyzed axial cross-sectional views with 2 mm intervals. In all cases, the volar surface of the distal radius was concave in the axial plane. The concavity depth was maximum at 6 mm proximal to the palmar edge of the lunate fossa and progressively decreased toward the proximal radius. FPL was closest to the radius at 2 mm proximal to the palmar edge of the lunate fossa. The volar surface of the distal radius was externally rotated from proximal to distal. These results may help to develop new implants which fit better to the radius and decrease tendon irritation.

  3. Golimumab for treatment of axial spondyloarthritis.

    Science.gov (United States)

    Rios Rodriguez, Valeria; Poddubnyy, Denis

    2016-02-01

    Axial spondyloarthritis comprises two forms: nonradiographic (nonradiographic axial spondyloarthritis) and radiographic (better known as ankylosing spondylitis), which are often considered as two stages of one disease. Historically, all currently available TNF-α inhibitors were first investigated in ankylosing spondylitis and later on in nonradiographic axial spondyloarthritis. This year, EMA has granted golimumab approval for the treatment of active nonradiographic axial spondyloarthritis based on the recently published data from the GO-AHEAD study. This article summarizes recent data on efficacy and safety of golimumab in the treatment of ankylosing spondylitis and nonradiographic axial spondyloarthritis.

  4. Sagittal synostosis: II. Cranial morphology and growth after the modified pi-plasty

    DEFF Research Database (Denmark)

    Guimaraes-Ferreira, J.; Gewalli, F.; David, L.;

    2006-01-01

    longitudinally. Forty-five children with unilateral incomplete cleft lip (UICL), evaluated longitudinally at the ages of 2.4 and 23.2 months were used as controls. A standardised radiocephalometric technique was used for image acquisition. The radiocephalograms were analysed using a modification of a method......The aim of this study was to characterise the postoperative cranial growth and morphology after a modified pi-plasty for sagittal synostosis. The shape of the skull of 82 patients with isolated premature synostosis of the sagittal suture ( SS group) operated on with a modified pi-plasty was studied...... selected landmarks, and angles defined by groups of three landmarks). Paired and unpaired t tests were used to assess the differences between the variables studied. These were accepted as significant for values of p...

  5. Lesion of the anterior cruciate ligament and sagittal disalignment of the knee in weight-bearing

    Energy Technology Data Exchange (ETDEWEB)

    Egund, N.; Friden, T.

    Twenty-nine patients with late reconstructive surgery for anterior cruciate ligament lesions had a clinical and radiologic follow-up ten years after injury. Anterior sagittal displacement of the tibia was recorded on the routine standing radiographs in 16 knees all having a normal femoro-tibial alignment in the non-weight-bearing position. Five of eleven patients with sagittal displacement of between 10 and 19 mm had early osteoarthrosis, which was confirmed by magnetic resonance imaging in four cases; their ages ranged from 23 to 38 years. No radiographic signs of osteoarthrosis were observed in those with displacements of less than 10 mm. In some patients there was a discrepancy between the clinical and radiographic measurements of instability. In addition to the clinical tests of instability standing rather than non-weight-bearing lateral radiographs are suggested for the routine assessment of cruciate ligament injuries.

  6. Scanogram for sagittal imbalance of the spine: low dose alternative for a safer diagnosis.

    Science.gov (United States)

    Weisz, George M; Albury, W R; Houang, M D; Matucci-Cerinic, Marco

    2014-01-01

    The diagnosis of Fixed Sagittal Imbalance (FSI), previously known as Flat Back Syndrome, requires the measurement of spinal curvatures on a lateral radiograph in the standing position (C7-S1). It can be difficult to position a spastic patient, sometimes repeated exposure are required, at separate thoracic and lumbar levels, increasing the radiation dosage. CT Scanography is suggested as an alternative radiological diagnostic method since it is rapid to perform. The patient is comfortably positioned (horizontal) and it combines both prone and supine positions, therefore acting as a functional examination. This test was performed on 34 consecutive patients with fractured vertebrae (lumbar, dorsal) and with back pain persisting beyond the bone healing period. The functional scanogram was found to be accurate in diagnosing sagittal imbalances, but more importantly it offered reduction in radiation: in Entrance dose; in Effective dose and Absorption dose. Scanogram is therefore proposed as an alternative method for the diagnosis of FSI.

  7. The Specific Sagittal Magnetic Resonance Imaging of Intradural Extra-Arachnoid Lumbar Disc Herniation

    Directory of Open Access Journals (Sweden)

    Tatsuro Sasaji

    2012-01-01

    Full Text Available Intradural extra-arachnoid lumbar disc herniation is a rare disease. Few MRI findings have been reported. We experienced an intradural extra-arachnoid lumbar disc herniation. We reviewed the preoperative MRI findings. Lumbar spine T2-weighted sagittal MRI showed that one line of the ventral dura was divided into two by a disc herniation. We speculated that the two lines comprised the dura and arachnoid and that a disc herniation existed between them. We believe that division of the ventral dural line on T2-weighted sagittal images is a characteristic finding of intradural extra-arachnoid lumbar disc herniation. The division of ventral dural line seemed to be a “Y,” and, thus, we called it the “Y sign.” The “Y sign” may be useful for diagnosing intradural extra-arachnoid lumbar disc herniation.

  8. The effect of sagittal laxity on function after posterior cruciate-retaining total knee replacement.

    Science.gov (United States)

    Jones, David P Gwynne; Locke, Conlin; Pennington, Jonathon; Theis, Jean-Claude

    2006-08-01

    We studied sagittal laxity using the KT1000 arthrometer in 97 total knee arthroplasties (TKAs) in 83 patients using the porous-coated anatomic knee or Duracon TKA (Howmedica, Rutherford, NJ) with 5.4- to 9.9-year follow-up. Two differing tibial inserts were used: flat (group 1) and anteroposterior (AP) lipped (group 2). Greater posterior and total laxity at 75 degrees was seen in group 2 despite the AP-lipped insert. No differences were seen in functional outcome scores between groups. No significant relationship was seen between laxity and functional outcome. Knees with more than 10 mm of AP laxity at 75 degrees had significantly less flexion and lower Knee Society Scores than knees with 5 to 10 mm of AP laxity. We conclude that the optimal sagittal laxity in this cruciate-retaining TKA is between 5 and 10 mm, although this may not hold for posterior-stabilized designs.

  9. Evaluation of fractured condylar head along the sagittal plane: report of three cases.

    Science.gov (United States)

    Rajesh Kumar, Bekal Pattathan; Rai, Kirthi Kumar; Shiva Kumar, H R; Upasi, Amarnath P; Shah, Ashwin

    2012-06-01

    There are case reports of sagittal fractures of the condylar head leading to bifid condyle. However bifid condyles maybe found in patients with no history of trauma. A split in the saggital plane of the condyle is not visible with a lateral, oblique or panaromic radiographs but only with anteriorposterior, transorbital projections or CT scan of the temperomandibular joint. The chances of condyle being split in the sagittal plane may be due to the medial pole extending beyond the condylar neck, moreover the condyle is composed of cancellous bone covered by a thin layer of cortical bone. Here we are presenting three case reports of Saggital split condyles and stress the need for inclusion of these type of fractures in the classification of condylar fractures.

  10. Melanotic Neuroectodermal Tumor of Infancy with Involvement of the Superior Sagittal Sinus.

    Science.gov (United States)

    Foster, Kimberly A; Choudhri, Asim; Lingo, Ryan; Boop, Frederick

    2017-01-01

    Melanotic neuroectodermal tumor of infancy (MNTI) is a rare lesion that typically manifests in the first year of life, most commonly involving the facial bones. We present 2 infants with MNTI involving the posterior skull with associated compression of the superior sagittal sinus (SSS). A review of the anatomical locations of MNTI is offered, and the implications of SSS involvement are described. This represents the first known description of MNTI with involvement of the posterior SSS.

  11. Maxillomandibular Advancement in Obstructive Sleep Apnea Syndrome Patients: a Restrospective Study on the Sagittal Cephalometric Variables

    OpenAIRE

    2013-01-01

    ABSTRACT Objectives The present retrospective study analyzes sagittal cephalometric changes in patients affected by obstructive sleep apnea syndrome submitted to maxillomandubular advancement. Material and Methods 15 adult sleep apnea syndrome (OSAS) patients diagnosed by polysomnography (PSG) and treated with maxillomandubular advancement (MMA) were included in this study. Pre- (T1) and postsurgical (T2) PSG studies assessing the apnea/hypopnea index (AHI) and the lowest oxygen saturation (L...

  12. Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion

    OpenAIRE

    Kumar, Malhar; Baklanov, Andrei; Chopin, Daniel

    2001-01-01

    Adjacent segment degeneration following lumbar spine fusion remains a widely acknowledged problem, but there is insufficient knowledge regarding the factors that contribute to its occurrence. The aim of this study is to analyse the relationship between abnormal sagittal plane configuration of the lumbar spine and the development of adjacent segment degeneration. Eighty-three consecutive patients who underwent lumbar fusion for degenerative disc disease were reviewed retrospectively. Patients ...

  13. Cheiloscopy: A new role as a marker of sagittal jaw relation

    Directory of Open Access Journals (Sweden)

    Narayan Kulkarni

    2012-01-01

    Full Text Available Context: It has been proved that lip prints are analogous to thumb prints. A correlation between thumb prints and sagittal dental malocclusion has already been established. Soft tissue is gaining more importance in judgement of deformity or identity of a patient. Aim: To find a correlation between sagittal skeletal jaw relation and lip prints. Settings and Design: Descriptive, cross-sectional, comparative, single-blind, hospital-based study. Materials and Methods: A total of 90 patients were categorized into skeletal class I, class II, and class III, comprising 30 patients in each group with equal gender distribution. Dolphin imaging (10.5 software was used for analyzing sagittal jaw relation. Lip prints obtained from these 90 patients were analyzed. Statistical Analyses Used: Karl Pearson′s correlation coefficient, Chi-square test, t-test, Spearman′s co-efficient, analysis of variance (ANOVA. Results: It was observed that angle ANB (Angle formed between points nasion[N] to Subnasal[A] and nasion[N] to supramental [B] and beta angle were statistically significant, revealing a strong negative correlation (-0.9060 with different classes of jaw relation. Significant difference was observed between genders in all the three classes. Significant difference was observed in relation to lip print and the quadrants of upper and lower lips. A statistical significance was noted on the right side of both upper and lower arches. Conclusion: This study shows that lip prints can be employed for sagittal jaw relation recognition. A further study on various ethnic backgrounds with a larger sample size in individual group is necessary for comparing lip prints and malocclusion.

  14. Determination of craniofacial relation among the subethnic Indian population: A modified approach - (Sagittal relation

    Directory of Open Access Journals (Sweden)

    A Sumathi Felicita

    2012-01-01

    Full Text Available Aim : To measure the linear cephalometric dimensions of anterior and posterior segments of the craniofacial complex sagittally, to establish ratios between different linear dimensions of sagittal segments and check for dimensional balance among the various segments in subjects with normal occlusion, pleasing profile and facial harmony. Setting and Sample Population : Department of Orthodontics, Saveetha University. Lateral cephalograms of 120 subjects of both sexes in the age group of 17-28 years with normal occlusion belonging to Chennai, India Materials and Methods : Linear dimensions of anterior and posterior segments of the craniofacial complex were measured sagittally with the posterior maxillary plane as a key reference plane. Ratios were established between the various parameters in the anterior and posterior region. Results : A ratio of 1:1 was found to exist between the individual and aggregate sagittal segments of the craniofacial complex in both sexes. There was a statistically significant sexual dimorphism in the aggregate lengths(P=0.028,P=0.005.However, the ratio between the anterior cranial floor and effective maxillary length was 2:3 and 5:8 and that between anterior cranial floor to effective mandibular length was 5:8 and 3:5 in females and males respectively. The difference in the above values was not statistically significant. Conclusion : A dimensional balance was found to exist between the maxilla and mandible both at the dentoalveolar and skeletal level with a ratio of 1:1. There was also a dimensional balance between the posterior cranial floor and ramus width. However, there was no architectural balance between the anterior cranial floor and maxilla and mandible.

  15. INFLUENCE OF THE SAGITTAL BALANCE ON THE CLINICAL OUTCOME IN SPINAL FUSION

    OpenAIRE

    2016-01-01

    ABSTRACT Objective: Evaluates which radiographic parameters of the sagittal and spinopelvic balance influence the clinical and functional outcomes of a sample of patients undergoing spinal fusion. Methods: We studied 32 patients who underwent spinal fusion. Radiographs of the total spine were obtained from all patients. The clinical and functional parameters studied were analysis of pain by visual analogic scale (VAS) and Oswestry and SRS-30 questionnaires. We analyzed the correlation bet...

  16. Clinical Impact of Sagittal Spinopelvic Parameters on Disc Degeneration in Young Adults.

    Science.gov (United States)

    Oh, Young-Min; Eun, Jong-Pil

    2015-10-01

    The sagittal balance plays an important role in the determination of shear and compressive forces applied on the anterior (vertebral bodies and intervertebral discs) and posterior (facet joints) elements of the lumbar vertebral column. Many studies have also examined the effect of structural changes in the disc on the biomechanical characteristics of the spinal segment. Nevertheless, the relationship between sagittal balance and the degree of disc degeneration has not been extensively explored. Thus, here we investigated the relationships between various sagittal spinopelvic parameters and the degree of disc degeneration in young adults.A total of 278 young adult male patients were included in this study (age range: 18-24 years old). Multiple sagittal spinopelvic parameters, including pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), sacral inclination (SI), lumbosacral angle (LSA), and sacral table angle (STA), were measured from standing lateral lumbosacral radiographs. The degree of intervertebral disc degeneration was classified using a modified Pfirrmann scale. To assess the pain intensity of each patient, the visual analogue scale (VAS) score for low back pain (LBP) was obtained from all the patients. Finally, the relationships between these spinopelvic parameters and the degree of disc degeneration in young adults were analyzed. Also, we performed multiple logistic regression study.Out of all the spinopelvic parameters measured in this study, a low STA and a low SI were the only significant risk factors that were associated with disc degeneration in young adults. It means that patients with disc degeneration tend to have more severe sacral kyphosis and vertical sacrum.We found that patients with disc degeneration showed a lower SI and lower STA compared with patients without disc degeneration in young adults. Therefore, we suggest that the patients with disc degeneration tend to have more vertical sacrum, more sacral kyphosis

  17. Cervical spine sagittal alignment variations following posterior spinal fusion and instrumentation for adolescent idiopathic scoliosis

    OpenAIRE

    2011-01-01

    The aim of this study is to quantify the changes in the sagittal alignment of the cervical spine in patients with adolescent idiopathic scoliosis following posterior spinal fusion. Patients eligible for study inclusion included those with a diagnosis of mainly thoracic adolescent idiopathic scoliosis treated by means of posterior multisegmented hook and screw instrumentation. Pre and post-operative anterior–posterior and lateral radiographs of the entire spine were reviewed to assess the chan...

  18. Influence of neck pain on cervical movement in the sagittal plane during smartphone use

    OpenAIRE

    2015-01-01

    [Purpose] Smartphone use reportedly changes posture. However, how neck posture is altered in smartphone users with neck pain is unknown. This study examined changes in the posture of young adults with and without mild neck pain (MNP) when using a smartphone. [Subjects] Thirteen control subjects and 14 subjects with MNP who used smartphones were recruited. [Methods] The upper cervical (UC) and lower cervical (LC) angles in the sagittal plane were measured using an ultrasound-based motion analy...

  19. Sagittal Plane Knee Biomechanics and Vertical Ground Reaction Forces Are Modified Following ACL Injury Prevention Programs

    Science.gov (United States)

    Padua, Darin A.; DiStefano, Lindsay J.

    2009-01-01

    Context: Injuries to the anterior cruciate ligament (ACL) occur because of excessive loading on the knee. ACL injury prevention programs can influence sagittal plane ACL loading factors and vertical ground reaction force (VGRF). Objective: To determine the influence of ACL injury prevention programs on sagittal plane knee biomechanics (anterior tibial shear force, knee flexion angle/moments) and VGRF. Data Sources: The PubMed database was searched for studies published between January 1988 and June 2008. Reference lists of selected articles were also reviewed. Study Selection: Studies were included that evaluated healthy participants for knee flexion angle, sagittal plane knee kinetics, or VGRF after performing a multisession training program. Two individuals reviewed all articles and determined which articles met the selection criteria. Approximately 4% of the articles fulfilled the selection criteria. Data Extraction: Data were extracted regarding each program’s duration, frequency, exercise type, population, supervision, and testing procedures. Means and variability measures were recorded to calculate effect sizes. One reviewer extracted all data and assessed study quality using PEDro (Physiotherapy Evidence Database). A second reviewer (blinded) verified all information. Results: There is moderate evidence to indicate that knee flexion angle, external knee flexion moment, and VGRF can be successfully modified by an ACL injury prevention program. Programs utilizing multiple exercises (ie, integrated training) appear to produce the most improvement, in comparison to that of single-exercise programs. Knee flexion angle was improved following integrated training (combined balance and strength exercises or combined plyometric and strength exercises). Similarly, external knee flexion moment was improved following integrated training consisting of balance, plyometric, and strength exercises. VGRF was improved when incorporating supervision with instruction and

  20. Sagittal jaw position in relation to body posture in adult humans – a rasterstereographic study

    Directory of Open Access Journals (Sweden)

    Drerup Burkhard

    2006-01-01

    Full Text Available Abstract Background The correlations between the sagittal jaw position and the cranio – cervical inclination are described in literature. Only few studies focus on the sagittal jaw position and the body posture using valid and objective orthopaedic examination methods. The aim of this study was to test the hypothesis that patients with malocclusions reveal significant differences in body posture compared to those without (upper thoracic inclination, kyphotic angle, lordotic angle and lower lumbar inclination. Methods Eighty-four healthy adult patients (with a mean age = 25.6 years and ranging from 16.1 to 55.8 years were examined with informed consent. The orthodontic examination horizontal overjet (distance between upper and lower incisors was determined by using an orthodontic digital sliding calliper. The subjects were subdivided in respect of the overjet with the following results: 18 revealed a normal overjet (Class I, 38 had an increased overjet (Class II and 28 had an reversed overjet (Class III. Rasterstereography was used to carry out a three – dimensional back shape analysis. This method is based on photogrammetry. A three-dimensional shape was produced by analysing the distortion of parallel horizontal white light lines projected on the patient's back, followed by mathematical modelling. On the basis of the sagittal profile the upper thoracic inclination, the thoracic angle, the lordotic angle and the pelvic inclination were determined with a reported accuracy of 2.8° and the correlations to the sagittal jaw position were calculated by means of ANOVA, Scheffé and Kruskal-Wallis procedures. Results Between the different overjet groups, no statistically significant differences or correlations regarding the analysed back shape parameters could be obtained. However, comparing males and females there were statistically significant differences in view of the parameters 'lordotic angle' and 'pelvic inclination'. Conclusion No

  1. Age-Related Changes in Cervical Sagittal Range of Motion and Alignment

    OpenAIRE

    Park, Moon Soo; Moon, Seong-Hwan; Lee, Hwan-Mo; Kim, Tae-Hwan; Oh, Jae Keun; Nam, Ji Hoon; Riew, K. Daniel

    2014-01-01

    Study Design Retrospective cohort study. Objective To compare sagittal cervical range of motion (ROM) and alignment in young versus middle-aged adults. Methods One hundred four asymptomatic adults were selected randomly out of 791 subjects who underwent lateral cervical radiographs in neutral, flexion, and extension positions. They were divided into two groups: young (age 20 to 29, 52 people) and middle-aged adults (age 50 to 59, 52 people). We determined the ROMs of upper cervical (occipital...

  2. CORRELATION BETWEEN OBESITY, SAGITTAL BALANCE AND CLINICAL OUTCOME IN SPINAL FUSION

    Directory of Open Access Journals (Sweden)

    Marcel Machado da Motta

    2015-09-01

    Full Text Available Objective:To correlate obesity with radiographic parameters of spinal and spinopelvic balance in patients undergoing spinal arthrodesis, and to correlate obesity with clinical outcome of these patients.Methods:Observational retrospective study including patients who underwent spinal arthrodesis, with minimum follow-up period of three months. We measured waist circumference, as well as height and weight to calculate body mass index (BMI and obtained radiographs of the total column. The clinical parameters studied were pain by visual analog scale (VAS and the Oswestry questionnaire (ODI. Obesity correlated with radiographic parameters of the sagittal and spinopelvic balance and postoperative clinical parameters.Results:32 patients were analyzed. The higher the BMI, the greater the value of VAS found, but without statistical significance (p=0.83. There was also no correlation between BMI and the ODI questionnaire. Analyzing the abdominal circumference, there was no correlation between the VAS and ODI. There was no correlation between BMI or waist circumference and the radiographic parameters of global spinopelvic sagittal alignment. Regarding the postoperative results, there was no correlation between the mean BMI and waist circumference and the postoperative results for ODI and VAS (p=0.75 and p=0.7, respectively.Conclusions:The clinical outcomes of patients who undergone spinal fusion were not affected by the BMI and waist circumference. Also, there was no correlation between radiographic parameters of spinal and spinopelvic sagittal balance with obesity in patients previously treated with arthrodesis of the spine.

  3. WAVELET ANALYSIS AND NEURAL NETWORK CLASSIFIERS TO DETECT MID-SAGITTAL SECTIONS FOR NUCHAL TRANSLUCENCY MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Giuseppa Sciortino

    2016-04-01

    Full Text Available We propose a methodology to support the physician in the automatic identification of mid-sagittal sections of the fetus in ultrasound videos acquired during the first trimester of pregnancy. A good mid-sagittal section is a key requirement to make the correct measurement of nuchal translucency which is one of the main marker for screening of chromosomal defects such as trisomy 13, 18 and 21. NT measurement is beyond the scope of this article. The proposed methodology is mainly based on wavelet analysis and neural network classifiers to detect the jawbone and on radial symmetry analysis to detect the choroid plexus. Those steps allow to identify the frames which represent correct mid-sagittal sections to be processed. The performance of the proposed methodology was analyzed on 3000 random frames uniformly extracted from 10 real clinical ultrasound videos. With respect to a ground-truth provided by an expert physician, we obtained a true positive, a true negative and a balanced accuracy equal to 87.26%, 94.98% and 91.12% respectively.

  4. Analysis of sagittal balance and spinopelvic parameters in a brazilian population sample

    Directory of Open Access Journals (Sweden)

    Raphael De Rezende Pratali

    2014-01-01

    Full Text Available Objective: To define the sagittal balance and spinopelvic parameters in a Brazilian population sample composed of asymptomatic volunteers. Methods: Fifty healthy adult individuals volunteered to participate in this study. The exclusion criteria included spinal deformity or improper radiograph study. In each radiograph exam in profile view, the sagittal balance and spinopelvic parameters were evaluated, including vertical sagittal axis, sacral slope, pelvic tilt and pelvic incidence. Results: The data obtained in this study are according to the values presented in the worldwide literature. None of the radiographic parameters showed any differences between the genders. Comparing the values presented in this study with those of other reports, with different populations, it was observed that: there was no significant difference in any of the pelvic parameters between Brazilian and Korean populations; there was a significant difference in pelvic incidence between Brazilian and European populations in a total sample (p=0.0001, in males (p=0.02, and in females (p=0.0007; there was a difference in sacral slope between Brazilian and European populations in a total sample (p=0.0140, and in females (p=0.005. Conclusion: There were no differences in any parameter in terms of gender. There were no differences in pelvic incidence between Brazilian and Korean populations. There was a difference in pelvic incidence between Brazilian and European populations, in the total sample and in males and females. There was a difference in sacral slope between Brazilian and European populations in a total sample, and in females.

  5. Pelvic parameters of sagittal balance in extreme lateral interbody fusion for degenerative lumbar disc disease.

    Science.gov (United States)

    Johnson, R D; Valore, A; Villaminar, A; Comisso, M; Balsano, M

    2013-04-01

    There is increasing interest in the use of pelvic indices to evaluate sagittal balance and predict outcomes in patients with spinal disease. Conventional posterior lumbar fusion techniques may adversely affect lumbar lordosis and spinal balance. Minimally invasive fusion of the lumbar spine is rapidly becoming a mainstay of treatment of lumbar degenerative disc disease. To our knowledge there are no studies evaluating the effect of extreme lateral interbody fusion (XLIF) on pelvic indices. Hence, our aim was to study the effect of XLIF on pelvic indices related to sagittal balance, and report the results of a prospective longitudinal clinical study and retrospective radiographic analyses of patients undergoing XLIF in a single centre between January 2009 and July 2011. Clinical outcomes are reported for 30 patients and the retrospective analyses of radiographic data is reported for 22 of these patients to assess global and segmental lumbar lordosis and pelvic indices. Effect of XLIF on the correction of scoliotic deformity was assessed in 15 patients in this series. A significant improvement was seen in the visual analogue scale score, the Oswestry Disability Index and the Short Form-36 at 2months and 6months (p0.2). Global lumbar lordosis was not affected by XLIF (p>0.4). XLIF significantly increased segmental lumbar lordosis by 3.3° (psagittal balance. Long-term follow-up with a larger cohort will be required to further evaluate the effects of XLIF on sagittal balance.

  6. Sagittal rotational stiffness and damping increase in a porcine lumbar spine with increased or prolonged loading.

    Science.gov (United States)

    Zondervan, Robert L; Popovich, John M; Radcliffe, Clark J; Pathak, Pramod K; Reeves, N Peter

    2016-02-29

    While the impact of load magnitude on spine dynamic parameters (stiffness and damping) has been reported, it is unclear how load history (exposure to prolonged loading) affects spine dynamic parameters in sagittal rotation. Furthermore, it is unknown if both spine stiffness and damping are equally affected to prolonged loading. Using a pendulum testing apparatus, the effect of load magnitude and load history on spine sagittal rotational stiffness and damping was assessed. Nine porcine lumbar functional spine units (FSUs) were tested in an increasing compressive load phase (ICP: 44.85, 68.55, 91.75, 114.6kg) and then a decreasing compressive load phase (DCP: 91.75, 68.55, and 44.85kg). Each trial consisted of flexing the FSU 5° and allowing it to oscillate unconstrained. During the ICP, both stiffness and damping linearly increased with load. However, in the DCP, stiffness and damping values were significantly higher than the identical load collected during the ICP, suggesting load history affects sagittal rotational dynamic parameters. In addition, spine damping was more affected by load history than spine stiffness. These results highlight the importance of controlling load magnitude and history when assessing spine dynamic parameters.

  7. The Role of Proprioception in the Sagittal Setting of Anticipatory Postural Adjustments During Gait Initiation

    Directory of Open Access Journals (Sweden)

    Pereira Marcelo P.

    2015-12-01

    Full Text Available Purpose. Previous studies have studied the role of proprioception on the setting of anticipatory postural adjustments (APA during gait initiation. However, these studies did not investigate the role of proprioception in the sagittal APA setting. We aimed to investigate the role of proprioception manipulation to induce APA sagittal adaptations on gait initiation. Methods. Fourteen healthy adults performed gait initiation without, and with, vibration applied before movement onset, and during movement. In addition, the effects of two different vibration frequencies (80 and 120Hz were tested. Vibration was applied bilaterally on the tibialis anterior, rectus femoris and trapezius superior. The first step characteristics, ground reaction forces and CoP behaviour were assessed. Results. Vibration improved gait initiation performance regardless of the moment it was applied. CoP velocity during the initial phase of APA was increased by vibration only when it was applied before movement. When vibration was applied to disturb the movement, no effects on the CoP behaviour were observed. Manipulation of vibration frequency had no effects. Conclusions. Rather than proprioception manipulation, the results suggest that post-vibratory effects and attentional mechanisms were responsible for our results. Taken together, the results show that sagittal APA setting is robust to proprioception manipulation.

  8. Utility of coronal oblique slices in cervical spine MRI. Improved detection of the neuroforamina; Nutzen der halbkoronaren Schichtung im MRT der Halswirbelsaeule. Verbesserte Erkennbarkeit von Neuroforamina

    Energy Technology Data Exchange (ETDEWEB)

    Freund, W.; Hoepner, G. [Universitaetskliniken Ulm, Klinik fuer Diagnostische und Interventionelle Radiologie, Ulm (Germany); Klessinger, S. [Nova Clinic Biberach, Neurochirurgie, Biberach (Germany); Universitaetskliniken Ulm, Neurochirurgie, Ulm (Germany); Mueller, M. [Universitaetskliniken Ulm, Klinik fuer Diagnostische und Interventionelle Radiologie, Ulm (Germany); Universitaetskliniken Aachen, Diagnostische und Interventionelle Neuroradiologie, Aachen (Germany); Halatsch, M.E. [Universitaetskliniken Ulm, Neurochirurgie, Ulm (Germany); Weber, F. [Bundeswehrkrankenhaus Ulm, Neurologie, Ulm (Germany); Schmitz, B. [Universitaetskliniken Ulm, Neuroradiologie, Ulm (Germany)

    2015-11-15

    Angulated projections are standard in conventional radiography of the cervical spine, but rarely used in magnetic resonance imaging (MRI). As neuroforaminal pathology plays an important role in the etiology of radicular syndromes and may influence an operative approach, the utility of coronal oblique slices in MRI is explored. In a retrospective setting, 25 consecutive patients with neurologically diagnosed cervical monoradiculopathy were identified. T2-weighted sagittal, coronal oblique, and transversal slice orientations were anonymized. Two radiologists and two neurosurgeons independently assessed the cases. Criteria were site, cause, and grading of the neuroforaminal stenosis and the level of confidence on a 100-point visual analog scale (VAS). We computed interrater agreement, sensitivity, and t tests. Using only one slice orientation, the sensitivity in detecting the relevant neuroforamen was 0.40 for transversal, 0.68 for sagittal, and 0.64 for coronal oblique scans. A combination of the different angulations increased sensitivity and in 4 cases only the coronal oblique scans proved diagnostic. The readers felt significantly more confident in attributing the cause of the pathology on coronal oblique planes (a mean of 72 VAS points, p = 0.0003 vs 58 (sagittal) vs 64 (transversal)). Interrater agreement was significantly better for experienced (kappa 0. 48) than for inexperienced readers (0.32, p = 0.02). Adding coronal oblique planes in cervical spine MRI increases sensitivity and confidence in attributing the cause of neuroforaminal pathology. They are regarded as useful by all the readers. (orig.) [German] Im Gegensatz zur Magnetresonanztomographie (MRT) sind in der konventionellen Roentgendiagnostik der Halswirbelsaeule (HWS) Schraegaufnahmen Standard. Da neuroforaminale Pathologien wichtige Ursachen von radikulaeren Syndromen sind und die Operationstechnik moeglicherweise beeinflussen, wird der Nutzen halbkoronarer Schichten in der MRT untersucht. In

  9. Solar jet-coronal hole collision and a related coronal mass ejection

    CERN Document Server

    Zheng, Ruisheng; Du, Guohui; Li, Chuanyang

    2016-01-01

    Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using the high-quality imaging data of AIA/SDO, here we show a well-observed coronal jet event, in which part of the jets, with the embedding coronal loops, runs into a nearby coronal hole (CH) and gets bounced towards the opposite direction. This is evidenced by the flat-shape of the jet front during its interaction with the CH and the V-shaped feature in the time-slice plot of the interaction region. About a half-hour later, a CME initially with a narrow and jet-like front is observed by the LASCO C2 coronagraph, propagating along the direction of the post-collision jet. We also observe some 304 A dark material flowing from the jet-CH interaction region towards the CME. We thus suggest that the jet and the CME are physically connected, with the jet-CH collision and t...

  10. SOLAR JET–CORONAL HOLE COLLISION AND A CLOSELY RELATED CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ruisheng; Chen, Yao; Du, Guohui; Li, Chuanyang, E-mail: ruishengzheng@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, 264209, Weihai (China)

    2016-03-10

    Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using high-quality imaging data from the Atmospheric Imaging Assembly/Solar Dynamics Observatory, we show a well-observed coronal jet event, in which the part of the jet with embedding coronal loops runs into a nearby coronal hole (CH) and gets bounced in the opposite direction. This is evidenced by the flat shape of the jet front during its interaction with the CH and the V-shaped feature in the time-slice plot of the interaction region. About a half-hour later, a CME with an initially narrow and jet-like front is observed by the LASCO C2 coronagraph propagating along the direction of the post-collision jet. We also observe some 304 Å dark material flowing from the jet–CH interaction region toward the CME. We thus suggest that the jet and the CME are physically connected, with the jet–CH collision and the large-scale magnetic topology of the CH being important in defining the eventual propagating direction of this particular jet–CME eruption.

  11. Cyclic Evolution of Coronal Fields from a Coupled Dynamo Potential-Field Source-Surface Model.

    Science.gov (United States)

    Dikpati, Mausumi; Suresh, Akshaya; Burkepile, Joan

    The structure of the Sun's corona varies with the solar-cycle phase, from a near spherical symmetry at solar maximum to an axial dipole at solar minimum. It is widely accepted that the large-scale coronal structure is governed by magnetic fields that are most likely generated by dynamo action in the solar interior. In order to understand the variation in coronal structure, we couple a potential-field source-surface model with a cyclic dynamo model. In this coupled model, the magnetic field inside the convection zone is governed by the dynamo equation; these dynamo-generated fields are extended from the photosphere to the corona using a potential-field source-surface model. Assuming axisymmetry, we take linear combinations of associated Legendre polynomials that match the more complex coronal structures. Choosing images of the global corona from the Mauna Loa Solar Observatory at each Carrington rotation over half a cycle (1986 - 1991), we compute the coefficients of the associated Legendre polynomials up to degree eight and compare with observations. We show that at minimum the dipole term dominates, but it fades as the cycle progresses; higher-order multipolar terms begin to dominate. The amplitudes of these terms are not exactly the same for the two limbs, indicating that there is a longitude dependence. While both the 1986 and the 1996 minimum coronas were dipolar, the minimum in 2008 was unusual, since there was a substantial departure from a dipole. We investigate the physical cause of this departure by including a North-South asymmetry in the surface source of the magnetic fields in our flux-transport dynamo model, and find that this asymmetry could be one of the reasons for departure from the dipole in the 2008 minimum.

  12. ON THE SUPPORT OF SOLAR PROMINENCE MATERIAL BY THE DIPS OF A CORONAL FLUX TUBE

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, Andrew [Kwasan and Hida Observatories, Kyoto University, Kyoto (Japan); Van Ballegooijen, Adriaan [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2013-04-01

    The dense prominence material is believed to be supported against gravity through the magnetic tension of dipped coronal magnetic field. For quiescent prominences, which exhibit many gravity-driven flows, hydrodynamic forces are likely to play an important role in the determination of both the large- and small-scale magnetic field distributions. In this study, we present the first steps toward creating a three-dimensional magneto-hydrostatic prominence model where the prominence is formed in the dips of a coronal flux tube. Here 2.5D equilibria are created by adding mass to an initially force-free magnetic field, then performing a secondary magnetohydrodynamic relaxation. Two inverse polarity magnetic field configurations are studied in detail, a simple o-point configuration with a ratio of the horizontal field (B{sub x} ) to the axial field (B{sub y} ) of 1:2 and a more complex model that also has an x-point with a ratio of 1:11. The models show that support against gravity is either by total pressure or tension, with only tension support resembling observed quiescent prominences. The o-point of the coronal flux tube was pulled down by the prominence material, leading to compression of the magnetic field at the base of the prominence. Therefore, tension support comes from the small curvature of the compressed magnetic field at the bottom and the larger curvature of the stretched magnetic field at the top of the prominence. It was found that this method does not guarantee convergence to a prominence-like equilibrium in the case where an x-point exists below the prominence flux tube. The results imply that a plasma {beta} of {approx}0.1 is necessary to support prominences through magnetic tension.

  13. Solar coronal observations at high frequencies

    OpenAIRE

    Katsiyannis, A. C.; Mathioudakis, M.; Phillips, K. J. H.; Williams, D. R.; F. P. Keenan

    2001-01-01

    The Solar Eclipse Coronal Imaging System (SECIS) is a simple and extremely fast, high-resolution imaging instrument designed for studies of the solar corona. Light from the corona (during, for example, a total solar eclipse) is reflected off a heliostat and passes via a Schmidt-Cassegrain telescope and beam splitter to two CCD cameras capable of imaging at 60 frames a second. The cameras are attached via SCSI connections to a purpose-built PC that acts as the data acquisition and storage syst...

  14. Observing coronal nanoflares in active region moss

    OpenAIRE

    Testa, Paola; De Pontieu, Bart; Martinez-Sykora, Juan; DeLuca, Ed; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Golub, Leon; Kobayashi, Ken; Korreck, Kelly; Kuzin, Sergey; Walsh, Robert; DeForest, Craig; Title, Alan; Weber, Mark

    2013-01-01

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial (~0.3-0.4 arcsec) and temporal (5.5s) resolution. The Hi-C observations show in some moss regions variability on timescales down to ~15s, significantly shorter than the minute scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss r...

  15. The structure of fast sausage waves in current-carrying coronal loops

    Science.gov (United States)

    Bembitov, D. B.; Mikhalyaev, B. B.; Ruderman, M. S.

    2014-09-01

    We study fast sausage waves in a model coronal loop that consists of a cylindrical core with axial magnetic field and coaxial annulus with purely azimuthal magnetic field. The magnetic field is discontinuous at the tube and core boundaries, and there are surface currents with the opposite directions on these boundaries. The principal mode of fast sausage waves in which the magnetic pressure perturbation has no nodes in the radial direction can exist for arbitrary wavelength. The results for the fundamental radial mode of sausage waves are applied to the interpretation of observed periodic pulsations of microwave emission in flaring loops with periods of a few tens of seconds. Radial plasma motion has opposite directions at the tube and core boundaries. This leads to the periodic contraction and expansion of the annulus. We assume that the principal mode of fast sausage waves in the current-carrying coronal loops is able to produce a current sheet. However, the nonlinear analysis is needed to confirm this conjecture.

  16. A clinico-radiographic analysis of sagittal condylar guidance determined by protrusive interocclusal registration and panoramic radiographic images in humans

    OpenAIRE

    Krishna Prasad, D.; Namrata Shah; Chethan Hegde

    2012-01-01

    Purpose: To evaluate the correlation between sagittal condylar guidance obtained by protrusive interocclusal records and panoramic radiograph tracing methods in human dentulous subjects. Materials and Methods: The sagittal condylar guidance was determined in 75 dentulous subjects by protrusive interocclusal records using Aluwax through a face bow transfer (HANAU™ Spring Bow, Whip Mix Corporation, USA) to a semi-adjustable articulator (HANAU™ Wide-Vue Articulator, Whip Mix Corporation, USA). I...

  17. Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

    Science.gov (United States)

    Mason, James Paul; Woods, Thomas N.; Webb, David F.; Thompson, Barbara J.; Colaninno, Robin C.; Vourlidas, Angelos

    2016-10-01

    Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar flare, as is often the case, the flare component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37 dimming events identified during two separate two-week periods in 2011 plus an event on 2010 August 7, analyzed in a previous paper to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to the dimming light curves, and compare the dimming parameters with corresponding CME parameters of mass and speed. The best linear relationships found are \\begin{eqnarray*}{v}{CME} ≤ft[\\displaystyle \\frac{{km}}{{{s}}}\\right] & ≈ & 2.36× {10}6 ≤ft[\\displaystyle \\frac{{km}}{ % }\\right]× {s}\\dim ≤ft[\\displaystyle \\frac{ % }{{{s}}}\\right]\\ {m}{CME} [{{g}}] & ≈ & 2.59× {10}15≤ft[\\displaystyle \\frac{g}{ % }\\right]× \\sqrt{{d}\\dim } [ % ].\\end{eqnarray*} These relationships could be used for space weather operations of estimating CME mass and speed using near-real-time irradiance dimming measurements.

  18. Evaluation of the Minifilament-Eruption Scenario for Solar Coronal Jets in Polar Coronal Holes

    Science.gov (United States)

    Baikie, Tomi K.; Sterling, Alphonse C.; Falconer, David; Moore, Ronald L.; Savage, Sabrina L.

    2016-01-01

    Solar coronal jets are suspected to result from magnetic reconnection low in the Sun's atmosphere. Sterling et al. (2015) looked as 20 jets in polar coronal holes, using X-ray images from the Hinode/X-Ray Telescope (XRT) and EUV images from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). They suggested that each jet was driven by the eruption of twisted closed magnetic field carrying a small-scale filament, which they call a 'minifilament', and that the jet was produced by reconnection of the erupting field with surrounding open field. In this study, we carry out a more extensive examination of polar coronal jets. From 180 hours of XRT polar coronal hole observations spread over two years (2014-2016), we identified 130 clearly-identifiable X-ray jet events and thus determined an event rate of over 17 jets per day per in the Hinode/XRT field of view. From the broader set, we selected 25 of the largest and brightest events for further study in AIA 171, 193, 211, and 304 Angstrom images. We find that at least the majority of the jets follow the minifilament-eruption scenario, although for some cases the evolution of the minifilament in the onset of its eruption is more complex than presented in the simplified schematic of Sterling et al. (2015). For all cases in which we could make a clear determination, the spire of the X-ray jet drifted laterally away from the jet-base-edge bright point; this spire drift away from the bright point is consistent with expectations of the minifilament-eruption scenario for coronal-jet production. This work was supported with funding from the NASA/MSFC Hinode Project Office, and from the NASA HGI program.

  19. Analysis of variation of sagittal position of the jaw bones in skeletal class III malocclusion

    Directory of Open Access Journals (Sweden)

    Stojanović Zdenka

    2012-01-01

    Full Text Available Background/Aim. Skeletal Class III malocclusion is a discrepancy in the sagittal jaw relationship, due to imbalances in their development and/or position, resulting in the dominant appearance of the lower jaw in facial profile. The aim of this study was to determine variations in the sagittal position of the jaw bones to the cranial base in subjects with skeletal Class III, for the earliest possible diagnosis of malocclusion. Methods. Fifty children and as many adults with skeletal Class III, both sexes, were examined and selected, based on the findings of sagittal interjaw relationship (ANB ≤ 0° from the cephalometric analysis of tele-x-ray profile head shots. The subjects were grouped according to age. The first group consisted of children aged 6-12 years, and another group, of adults aged 18-26 years. We measured the angles of maxillary prognathism (SNA, mandibular prognathism (SNB and ANB. Based on these results, within the respective groups subclassification into the subgroups was done, among which a significant difference measured values was evaluated. In both groups a significant correlation of the determined values was evaluated. Results. An average SNA angle ranged 77.36 ± 3.58 in children and 77.32 ± 4.88 in adults, while an average SNB angle was 79.46 ± 3.91 in the group of children and 81.12 ± 3.76 in adults. An average ANB angle was -2.10 ± 2.07 in children, and -4.00 ± 2.34 in adults. In both groups, a significant correlation between the measured values and a significant difference in the values of all the measured parameters were found between patients from different subgroups (p < 0.01. Conclusion. The most common morphological variation of sagittal position of the upper jaw is its retrognatism, which is equally present in both children and adults. Sagittal position of the lower jaw in most of the adults was prognathic, while mandible prognathism in the children was less present.

  20. Segmentation of Coronal Holes Using Active Contours Without Edges

    Science.gov (United States)

    Boucheron, L. E.; Valluri, M.; McAteer, R. T. J.

    2016-10-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. The detection and characterization of these regions is important for testing theories of their formation and evolution, and also from a space weather perspective because they are the source of the fast solar wind. Coronal holes are detected in full-disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than the surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. The means to identify a coronal hole without specifying a final intensity threshold may allow this algorithm to be more robust across multiple datasets, regardless of data type, resolution, and quality.

  1. Segmentation of Coronal Holes Using Active Contours Without Edges

    Science.gov (United States)

    Boucheron, L. E.; Valluri, M.; McAteer, R. T. J.

    2016-09-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. The detection and characterization of these regions is important for testing theories of their formation and evolution, and also from a space weather perspective because they are the source of the fast solar wind. Coronal holes are detected in full-disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than the surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. The means to identify a coronal hole without specifying a final intensity threshold may allow this algorithm to be more robust across multiple datasets, regardless of data type, resolution, and quality.

  2. SAUSAGE OSCILLATIONS OF CORONAL PLASMA STRUCTURES

    Energy Technology Data Exchange (ETDEWEB)

    Nakariakov, V. M.; Hornsey, C. [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Melnikov, V. F., E-mail: V.Nakariakov@warwick.ac.uk [Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 196140 St Petersburg (Russian Federation)

    2012-12-20

    The dependence of the period of sausage oscillations of coronal loops on length together with the depth and steepness of the radial profile are determined. We performed a parametric study of linear axisymmetric fast magnetoacoustic (sausage) oscillations of coronal loops modeled as a field-aligned low-{beta} plasma cylinder with a smooth inhomogeneity of the plasma density in the radial direction. The density decreases smoothly in the radial direction. Sausage oscillations are impulsively excited by a perturbation of the radial velocity, localized at the cylinder axis and with a harmonic dependence on the longitudinal coordinate. The initial perturbation results in either a leaky or a trapped sausage oscillation, depending upon whether the longitudinal wavenumber is smaller or greater than a cutoff value, respectively. The period of the sausage oscillations was found to always increase with increasing longitudinal wavelength, with the dependence saturating in the long-wavelength limit. Deeper and steeper radial profiles of the Alfven speed correspond to more efficient trapping of sausage modes: the cutoff value of the wavelength increases with the steepness and the density (or Alfven speed) contrast ratio. In the leaky regime, the period is always longer than the period of a trapped mode of a shorter wavelength in the same cylinder. For shallow density profiles and shorter wavelengths, the period increases with wavelength. In the long-wavelength limit, the period becomes independent of the wavelength and increases with the depth and steepness of the radial profile of the Alfven speed.

  3. Modified Homogeneous Data Set of Coronal Intensities

    Science.gov (United States)

    Dorotovič, I.; Minarovjech, M.; Lorenc, M.; Rybanský, M.

    2014-07-01

    The Astronomical Institute of the Slovak Academy of Sciences has published the intensities, recalibrated with respect to a common intensity scale, of the 530.3 nm (Fe xiv) green coronal line observed at ground-based stations up to the year 2008. The name of this publication is Homogeneous Data Set (HDS). We have developed a method that allows one to successfully substitute the ground-based observations by satellite observations and, thus, continue with the publication of the HDS. For this purpose, the observations of the Extreme-ultraviolet Imaging Telescope (EIT), onboard the Solar and Heliospheric Observatory (SOHO) satellite, were exploited. Among other data the EIT instrument provides almost daily 28.4 nm (Fe xv) emission-line snapshots of the corona. The Fe xiv and Fe xv data (4051 observation days) taken in the period 1996 - 2008 have been compared and good agreement was found. The method to obtain the individual data for the HDS follows from the correlation analysis described in this article. The resulting data, now under the name of Modified Homogeneous Data Set (MHDS), are identical up to 1996 to those in the HDS. The MHDS can be used further for studies of the coronal solar activity and its cycle. These data are available at http://www.suh.sk.

  4. Analytical investigations on the Coronation Gospels manuscript

    Science.gov (United States)

    Aceto, Maurizio; Agostino, Angelo; Fenoglio, Gaia; Idone, Ambra; Crivello, Fabrizio; Griesser, Martina; Kirchweger, Franz; Uhlir, Katharina; Puyo, Patricia Roger

    2017-01-01

    The Coronation Gospels or Krönungsevangeliar is a manuscript kept in Vienna at the Kunsthistorisches Museum Wien, datable to the end of VIII century A.D. and produced at Charlemagne court. It is an example of a purple codex, i.e. its parchment is coloured in purple. It has to be considered as one of the most important medieval codices, according to its use to take oath in the coronation ceremony of kings and emperors of the Holy Roman Empire up to 1792. In order to gather information of the manufacture of the manuscript and its present conservation state, a diagnostic investigation campaign has been carried out in situ with totally non-invasive techniques. X-ray Fluorescence Spectrometry (XRF), UV-visible diffuse reflectance spectrophotometry with optical fibres (FORS), spectrofluorimetry, optical microscopy and multispectral analysis have been applied in order to identify the colourants used in the decoration of the manuscript, with the main concern to the dye used to impart the purple hue to the parchment. The information collected was useful in order to address some of the questions raised by art historians concerning its history.

  5. Energetics of Solar Coronal Mass Ejections

    CERN Document Server

    Subramanian, P; Subramanian, Prasad; Vourlidas, Angelos

    2007-01-01

    Aims: To investigate if solar coronal mass ejections are driven mainly by coupling to the ambient solar wind, or through the release of internal magnetic energy. Methods: We examine the energetics of 39 flux-rope like coronal mass ejections (CMEs) from the Sun using data in the distance range $\\sim$ 2--20 $R_{{\\o}dot}$ from the Large Angle Spectroscopic Coronograph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). This comprises a complete sample of the best examples of flux-rope CMEs observed by LASCO in 1996-2001. Results: We find that 69% of the CMEs in our sample experience a clearly identifiable driving power in the LASCO field of view. For these CMEs which are driven, we examine if they might be deriving most of their driving power by coupling to the solar wind. We do not find conclusive evidence in favor of this hypothesis. On the other hand, we find that their internal magnetic energy is a viable source of the required driving power. We have estimated upper and lower limits on the power th...

  6. A Moreton Wave and its Coronal Counterparts

    Science.gov (United States)

    Francile, Carlos N.; Mandrini, Cristina H.; Long, David; Cremades, Hebe; Lopez, Fernando M.; Luoni, Maria Luisa

    2016-07-01

    On 29 March 2014, a Moreton wave was detected in AR 12017 with the Halpha Solar Telescope for Argentina (HASTA) in association with an X1 flare. Several phenomena took place in various regimes in connection with this event, such as low coronal waves and a coronal mass ejection (CME). We investigate their role and relationship with the Moreton wave to shed light on issues so far under debate. We analyze its connection with waves observed in the low corona with the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory (SDO/AIA), as well as with the ensuing CME, via kinematics analyses. We build stack plots from sequences of images obtained at different wavelengths to track wave fronts along several directions and find links between the features observed in the chromosphere and low corona, as well as in the associated CME. We also derive the shock front properties. We propose a geometrical model of the wave to explain the observed wave fronts as the photospheric and chromospheric traces of an expanding and outward-traveling bubble intersecting the Sun.

  7. Solar Wind Associated with Near Equatorial Coronal Hole

    Indian Academy of Sciences (India)

    M. Hegde; K. M. Hiremath; Vijayakumar H. Doddamani; Shashanka R. Gurumath

    2015-09-01

    Present study probes temporal changes in the area and radiative flux of near equatorial coronal hole associated with solar wind parameters such as wind speed, density, magnetic field and temperature. Using high temporal resolution data from SDO/AIA for the two wave-lengths 193 Å and 211 Å, area and radiative flux of coronal holes are extracted and are examined for the association with high speed solar wind parameters. We find a strong association between different parameters of coronal hole and solar wind. For both the wavelength bands, we also compute coronal hole radiative energy near the earth and it is found to be of similar order as that of solar wind energy. However, for the wavelength 193 Å, owing to almost similar magnitudes of energy emitted by coronal hole and energy due to solar wind, it is conjectured that solar wind might have originated around the same height where 193 Å line is formed in the corona.

  8. Observing Episodic Coronal Heating Events Rooted in Chromospheric Activity

    CERN Document Server

    McIntosh, Scott W

    2009-01-01

    We present results of a multi-wavelength study of episodic plasma injection into the corona of AR 10942. We exploit long-exposure images of the Hinode and Transition Region and Coronal Explorer (TRACE) spacecraft to study the properties of faint, episodic, "blobs" of plasma that are propelled upward along coronal loops that are rooted in the AR plage. We find that the source location and characteristic velocities of these episodic upflow events match those expected from recent spectroscopic observations of faint coronal upflows that are associated with upper chromospheric activity, in the form of highly dynamic spicules. The analysis presented ties together observations from coronal and chromospheric spectrographs and imagers, providing more evidence of the connection of discrete coronal mass heating and injection events with their source, dynamic spicules, in the chromosphere.

  9. Stellar Coronal Response to Differential Rotation and Flux Emergence

    CERN Document Server

    Gibb, G P S; Jardine, M M; Yeates, A R

    2016-01-01

    We perform a numerical parameter study to determine what effect varying differential rotation and flux emergence has on a star's non-potential coronal magnetic field. In particular we consider the effects on the star's surface magnetic flux, open magnetic flux, mean azimuthal field strength, coronal free magnetic energy, coronal heating and flux rope eruptions. To do this, we apply a magnetic flux transport model to describe the photospheric evolution, and couple this to the non-potential coronal evolution using a magnetofrictional technique. A flux emergence model is applied to add new magnetic flux onto the photosphere and into the corona. The parameters of this flux emergence model are derived from the solar flux emergence profile, however the rate of emergence can be increased to represent higher flux emergence rates than the Sun's. Overall we find that flux emergence has a greater effect on the non-potential coronal properties compared to differential rotation, with all the aforementioned properties incr...

  10. Axial Vector $Z'$ and Anomaly Cancellation

    CERN Document Server

    Ismail, Ahmed; Tsao, Kuo-Hsing; Unwin, James

    2016-01-01

    Whilst the prospect of new $Z'$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that the masses of these new states must generally be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.

  11. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and Coronal Streamer Area (6-40R)

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment during the first solar conjunction in summer 1991 (Bird et al., 1994), an estimate is presented of solar wind velocity profiles in a coronal hole and a coronal streamer area in the range between 6 and 40 solar radii.

  12. Diabetes mellitus and the eye: axial length

    OpenAIRE

    Huntjens, B.; O’Donnell, C.

    2006-01-01

    Background and aims: The refractive error of the eye is dependent on its axial length. Refractive error is known to fluctuate significantly in poorly controlled diabetic patients. Recently it has been reported that human eyes fluctuate in axial length during the day. However, this change is not detectable in all subjects, suggesting physiological influences such as diet. The purpose of this study was to investigate fluctuations in axial length and blood glucose levels (BGLs) in diabetic patie...

  13. System Study for Axial Vane Engine Technology

    Science.gov (United States)

    Badley, Patrick R.; Smith, Michael R.; Gould, Cedric O.

    2008-01-01

    The purpose of this engine feasibility study was to determine the benefits that can be achieved by incorporating positive displacement axial vane compression and expansion stages into high bypass turbofan engines. These positive-displacement stages would replace some or all of the conventional compressor and turbine stages in the turbine engine, but not the fan. The study considered combustion occurring internal to an axial vane component (i.e., Diesel engine replacing the standard turbine engine combustor, burner, and turbine); and external continuous flow combustion with an axial vane compressor and an axial vane turbine replacing conventional compressor and turbine systems.

  14. Utility of multilevel lateral interbody fusion of the thoracolumbar coronal curve apex in adult deformity surgery in combination with open posterior instrumentation and L5-S1 interbody fusion: a case-matched evaluation of 32 patients.

    Science.gov (United States)

    Theologis, Alexander A; Mundis, Gregory M; Nguyen, Stacie; Okonkwo, David O; Mummaneni, Praveen V; Smith, Justin S; Shaffrey, Christopher I; Fessler, Richard; Bess, Shay; Schwab, Frank; Diebo, Bassel G; Burton, Douglas; Hart, Robert; Deviren, Vedat; Ames, Christopher

    2017-02-01

    OBJECTIVE The aim of this study was to evaluate the utility of supplementing long thoracolumbar posterior instrumented fusion (posterior spinal fusion, PSF) with lateral interbody fusion (LIF) of the lumbar/thoracolumbar coronal curve apex in adult spinal deformity (ASD). METHODS Two multicenter databases were evaluated. Adults who had undergone multilevel LIF of the coronal curve apex in addition to PSF with L5-S1 interbody fusion (LS+Apex group) were matched by number of posterior levels fused with patients who had undergone PSF with L5-S1 interbody fusion without LIF (LS-Only group). All patients had at least 2 years of follow-up. Percutaneous PSF and 3-column osteotomy (3CO) were excluded. Demographics, perioperative details, radiographic spinal deformity measurements, and HRQoL data were analyzed. RESULTS Thirty-two patients were matched (LS+Apex: 16; LS: 16) (6 men, 26 women; mean age 63 ± 10 years). Overall, the average values for measures of deformity were as follows: Cobb angle > 40°, sagittal vertical axis (SVA) > 6 cm, pelvic tilt (PT) > 25°, and mismatch between pelvic incidence (PI) and lumbar lordosis (LL) > 15°. There were no significant intergroup differences in preoperative radiographic parameters, although patients in the LS+Apex group had greater Cobb angles and less LL. Patients in the LS+Apex group had significantly more anterior levels fused (4.6 vs 1), longer operative times (859 vs 379 minutes), and longer length of stay (12 vs 7.5 days) (all p fusion with or without multilevel LIF is used to treat a variety of coronal and sagittal adult thoracolumbar deformities. The addition of multilevel LIF to open PSF with L5-S1 interbody support in this small cohort was often used in more severe coronal and/or lumbopelvic sagittal deformities and offered better correction of major Cobb angles, lumbopelvic parameters, and SVA than posterior-only operations. As these advantages came at the expense of more major complications, more leg weakness

  15. The Emergence of Axial Parts

    Directory of Open Access Journals (Sweden)

    Peter Svenonius

    2007-01-01

    Full Text Available Many languages have specialized locative words or morphemes translating roughly into words like ‘front,’ ‘back,’ ‘top,’ ‘bottom,’ ‘side,’ and so on. Often, these words are used instead of more specialized adpositions to express spatial meanings corresponding to ‘behind,’ ‘above,’ and so on. I argue, on the basis of a cross-linguistic survey of such expressions, that in many cases they motivate a syntactic category which is distinct from both N and P, which I call AxPart for ‘Axial Part’; I show how the category relates to the words which instantiate it, and how the meaning of the construction is derived from the combination of P[lace] elements, AxParts, and the lexical material which expresses them.

  16. Unsteady Flows in Axial Turbomachines

    Science.gov (United States)

    Marble, F. E.; Rannie, W. D.

    1957-01-01

    Of the various unsteady flows that occur in axial turbomachines certain asymmetric disturbances, of wave length large in comparison with blade spacing, have become understood to a certain extent. These disturbances divide themselves into two categories: self-induced oscillations and force disturbances. A special type of propagating stall appears as a self-induced disturbance; an asymmetric velocity profile introduced at the compressor inlet constitutes a forced disturbance. Both phenomena have been treated from a unified theoretical point of view in which the asymmetric disturbances are linearized and the blade characteristics are assumed quasi-steady. Experimental results are in essential agreement with this theory wherever the limitations of the theory are satisfied. For the self-induced disturbances and the more interesting examples of the forced disturbances, the dominant blade characteristic is the dependence of total pressure loss, rather than the turning angle, upon the local blade inlet angle.

  17. A clinico-radiographic analysis of sagittal condylar guidance determined by protrusive interocclusal registration and panoramic radiographic images in humans

    Directory of Open Access Journals (Sweden)

    D Krishna Prasad

    2012-01-01

    Full Text Available Purpose: To evaluate the correlation between sagittal condylar guidance obtained by protrusive interocclusal records and panoramic radiograph tracing methods in human dentulous subjects. Materials and Methods: The sagittal condylar guidance was determined in 75 dentulous subjects by protrusive interocclusal records using Aluwax through a face bow transfer (HANAU™ Spring Bow, Whip Mix Corporation, USA to a semi-adjustable articulator (HANAU™ Wide-Vue Articulator, Whip Mix Corporation, USA. In the same subjects, the sagittal outline of the articular eminence and glenoid fossa was traced in panoramic radiographs. The sagittal condylar path inclination was constructed by joining the heights of curvature in the glenoid fossa and the corresponding articular eminence. This was then related to the constructed Frankfurt′s horizontal plane to determine the radiographic angle of sagittal condylar guidance. Results: A strong positive correlation existed between right and left condylar guidance by the protrusive interocclusal method (P 0.000 and similarly by the radiographic method (P 0.013. The mean difference between the condylar guidance obtained using both methods were 1.97° for the right side and 3.18° for the left side. This difference between the values by the two methods was found to be highly significant for the right (P 0.003 and left side (P 0.000, respectively. The sagittal condylar guidance obtained from both methods showed a significant positive correlation on right (P 0.000 and left side (P 0.015, respectively. Conclusion: Panoramic radiographic tracings of the sagittal condylar path guidance may be made relative to the Frankfurt′s horizontal reference plane and the resulting condylar guidance angles used to set the condylar guide settings of semi-adjustable articulators.

  18. [The influence of proprioceptive insoles (Bourdiol) on the sagittal curvature and inclination of the trunk].

    Science.gov (United States)

    Müller-Gliemann, C; Drerup, B; Osada, N; Wetz, H H

    2006-11-01

    Proprioceptive insoles rely on the concept of Réné-Jaques Bourdiol, a French neurologist. The aim is to modulate plantar surface sensibility and to influence posture and statics of patients: it is hypothesized that the effect of modified afferent sensory input through proprioceptive stimulation of terminal muscle chains will have either a relaxing or stimulating effect on the whole body, which may be realized by affecting the posture. Small pads with a thickness of typically 1-3 mm are embedded into the insole to provide a specific stimulation. In fitting the insoles selectively to the individual patient the effect of the insoles on the trunk posture is taken as a feedback. This study investigates the influence of proprioceptive insoles on the sagittal curve in 20 selected patients. The protocol used a repeated measures research design. The measures of the sagittal curve were obtained using raster stereography. The four different conditions were: (1) barefoot, (2) convenient shoes without the insoles, (3) the same shoes with a placebo insole, and (4) the same shoes with neurological insoles. Evaluation of raster stereographs provided the kyphotic angle between T4 and T12 and lordotic angle between T12 and S1. Statistical evaluation was performed with the t-test for paired measurements. No significant differences were found in the sagittal profile. Only trunk inclination in normal posture was found to yield a significant difference (0.38 degrees) between placebo and neurological insoles. However, no clear statement on the efficiency of neurological insoles can be made.

  19. Effects of extraction treatment on maxillary and mandibular sagittal development in growing patients.

    Science.gov (United States)

    Kalwitzki, Matthias; Godt, Arnim; Göz, Gernot

    2011-10-01

    This retrospective investigation was designed to assess the effects of extraction treatment on the sagittal dimensions of the maxillary and mandibular skeletal structures of growing patients. The records of 40 patients (17 girls, 23 boys; median age 10 years 11 months) whose orthodontic treatment involved extraction of four premolars were evaluated and compared with a control group of 100 patients (54 girls, 46 boys; median age 10 years 7 months) treated non-extraction. Two lateral cephalograms were obtained of each patient, the first before the extractions, T1, and the second at a later point, T2 (mean difference 59 months). Linear parameters, including S-N, the maxillary/mandibular alveolar process, and maxillary/mandibular base, were measured. The same parameters were determined in the control group at corresponding time points (mean difference 63 months). For analysis, the sagittal dimensions of the alveolar processes and jaw bases were compared with each other. The relationships were also established to a reference line known to be unaffected by extraction treatment (S-N). This procedure was performed for the whole sample and for three subgroups formed according to the Wits appraisal. Statistical analysis was carried out using a Student's t-test. Comparisons of the total sample showed differences between the groups, which were statistically significant for the maxillary alveolar process, the mandibular alveolar process, and the mandibular base. They varied however in the different subgroups. Whenever extraction treatment is considered, it should be borne in mind that the effects on the sagittal dimension of different bony structures may vary.

  20. 鼻咽癌颅底侵犯冠状位CT扫描应用价值分析%Analysis on value of CT coronal scan in diagnosis of invasion of skull base in nasopharyngeal carcinoma

    Institute of Scientific and Technical Information of China (English)

    骆忠华

    2012-01-01

    OBJECTIVE To discuss the clinical value of CT coronal scan in diagnosis of invasion of skull base in nasopharyn-geal carcinoma (NPC). METHODS 233 patients with NPC were given CT coronal and axial scan, then compared the results of the two positions. RESULTS In the 233 cases of NPC, CT coronal scan showed bone invasion in 4 cases in 16 cases that had not been recognized by axial scan. By CT coronal scan, the invasion of skull base was confirmed in 4 and excluded in 6 of 10 cases in which the invasion was uncertain by axial scan. Wider and deeper invasions were recognized in 23 cases (12.3%) by coronal scan, though obvious invasion had been diagnosed after axial scan. Accordant invasion was displayed in 35 cases (18.8%) by CT coronal and axial scan. By CT coronal scan, the invasion of skull base was in 21 patients witch had not been showed destruction of bone. And there was destruction of bone in 21 cases by axial scan, only 12 cases could be recognized in coronal scan, and with different locations. CONCLUSION CT scan is valuable for invasion of skull base in NPC, combining CT axial with coronal scan can improve diagnostic accuracy.%目的 探讨冠状位CT扫描在鼻咽癌颅底侵犯诊断中的应用价值.方法 对233例鼻咽癌患者进行轴位及冠状位CT扫描,比较两种体位对鼻咽癌颅底侵犯的检出情况.结果 轴位扫描所见肿瘤侵袭、转移灶中173例经冠状位扫描证实;轴位扫描无骨质侵袭及转移者16例中,经冠状位扫描见4例骨质破坏;轴位扫描所见10例难以确定是否骨质破坏者,经冠状位扫描证实4例骨质破坏,6例正常;另外,冠状位扫描显示了21例轴位扫描未发现的骨质破坏;同时有21例患者轴位扫描可见骨质破坏,但冠状位仅显示12例,且位置不同.结论 CT扫描在鼻咽癌颅底侵犯影像诊断中具有重要意义,但单纯轴位扫描具有一定局限性,联合应用轴位与冠状位的扫描,可提高诊断准确率.

  1. Kinematics of an untwisting solar jet in polar coronal hole observed by SDO/AIA

    CERN Document Server

    Chen, Huadong; Ma, Suli

    2012-01-01

    Using the multi-wavelength data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) spacecraft, we study a jet occurred in coronal hole near the northern pole of the Sun. The jet presented distinct helical upward motion during ejection. By tracking six identified moving features (MFs) in the jet, we found that the plasma moved at an approximately constant speed along the jet's axis, meanwhile, they made a circular motion in the plane transverse to the axis. Inferred from linear and trigonometric fittings to the axial and transverse heights of the six tracks, the mean values of axial velocities, transverse velocities, angular speeds, rotation periods, and rotation radiuses of the jet are 114 km s$^{-1}$, 136 km s$^{-1}$, 0.81\\degr\\ s$^{-1}$, 452 s, and 9.8 $\\times$ 10$^{3}$ km respectively. As the MFs rose, the jet width at the corresponding height increased. For the first time, we derived the height variation of the longitudinal magnetic field strength in the jet from the...

  2. [Superior sagittal sinus thrombosis caused by Crohn's disease and macrocytic anemia : a case report].

    Science.gov (United States)

    Osawa, Shigeyuki; Suzuki, Sachio; Yamada, Masaru; Fukushima, Yutaka; Utsuki, Satoshi; Shimizu, Satoru; Kurata, Akira; Fujii, Kiyotaka; Kan, Shinichi

    2007-06-01

    A 32-years-old man with a past history of hemorrhoids presenting with hemiparesis was diagnosed as having sagittal sinus thrombosis with hemorrtagic infarction. Laboratory data revealed macrocytic anemia (Hb 11.2 g/d/) with hypoproteinernia (5.5 g/d). After discharge the patient developed abdominal pain, diarrhea, edema in the leg and sustained anemia. Final diagnosis through colon fiberscope findings was Crohn's disease Macrocytic anemia seemed to be induced by Vit. B12 deficiency due to malabsorption. The mechanism and causal relationship between Crohn's disease and sinus thrombosis is discussed.

  3. Estimation and Perturbation of the Mid-Sagittal Plane and its Effects on Corpus Callosum Morphometry

    DEFF Research Database (Denmark)

    Skoglund, Karl; Stegmann, Mikkel Bille; Ryberg, Charlotte

    2005-01-01

    Brain morphometry is an important tool for detecting and monitoring brain pathologies such as epilepsy, dementia [1,2] and multiple sclerosis [3]. A common method is to delineate some well-defined area of the brain to yield a shape for interor intra-subject studies. One such structure is the corpus...... callosum (CC), the white-matter nervous tissue bridging the left and right cerebral hemisphere. A multitude of papers (e.g. [2]) report on measurements performed on the two-dimensional cross-section of the CC defined by the mid-sagittal plane (MSP) which separates the left hemisphere from the right...

  4. Tangential and sagittal curvature from the normals computed by the null screen method in corneal topography

    Science.gov (United States)

    Estrada-Molina, Amilcar; Díaz-Uribe, Rufino

    2011-08-01

    A new method for computing the tangential and sagittal curvatures from the normals to a cornea is proposed. The normals are obtained through a Null Screen method from the coordinates of the drops shaped spots at the null screen, the coordinates on a reference approximating surface and the centroids on the image plane. This method assumes that the cornea has rotational symmetry and our derivations will be carried out in the meridional plane that contains the symmetry axis. Experimental results are shown for a calibration spherical surface, using cylindrical null screens with radial point arrays.

  5. Magnetic structure of Coronal Mass Ejections

    CERN Document Server

    Lyutikov, Maxim

    2012-01-01

    We present several models of the magnetic structure of solar coronal mass ejections (CMEs). First, we model CMEs as expanding force-free magnetic structures. While keeping the internal magnetic field structure of the stationary solutions, expansion leads to complicated internal velocities and rotation, while the field structures remain force-free. Second, expansion of a CME can drive resistive dissipation within the CME changing the ionization states of different ions. We fit in situ measurements of ion charge states to the resistive spheromak solutions. Finally, we consider magnetic field structures of fully confined stable magnetic clouds containing both toroidal and poloidal magnetic fields and having no surface current sheets. Expansion of such clouds may lead to sudden onset of reconnection events.

  6. Coronal Mass Ejections: From Sun to Earth

    Science.gov (United States)

    Patsourakos, S.

    2016-06-01

    Coronal Mass Ejections (CMEs) are gigantic expulsions of magnetized plasmas from the solar corona into the interplanetary (IP) space. CMEs spawn ~ 1015 gr of mass and reach speeds ranging between several hundred to a few thousand km/s (e.g., Gopalswamy et al. 2009; Vourlidas et al. 2010). It takes 1-5 days for a CME to reach Earth. CMEs are one of the most energetic eruptive manifestations in the solar system and are major drivers of space weather via their magnetic fields and energetic particles, which are accelerated by CME-driven shocks. In this review we give a short account of recent, mainly observational, results on CMEs from the STEREO and SDO missions which include the nature of their pre-eruptive and eruptive configurations and the CME propagation from Sun to Earth. We conclude with a discussion of the exciting capabilities in CME studies that will soon become available from new solar and heliospheric instrumentation.

  7. Coronal Neutrino Emission in Hypercritical Accretion Flows

    CERN Document Server

    Kawabata, R; Kawanaka, N

    2007-01-01

    Hypercritical accretion flows onto stellar mass black holes (BHs) are commonly considered as a promising model of central engines of gamma-ray bursts (GRBs). In this model a certain fraction of gravitational binding energy of accreting matter is deposited to the energy of relativistic jets via neutrino annihilation and/or magnetic fields. However, some recent studies have indicated that the energy deposition rate by neutrino annihilation is somewhat smaller than that needed to power a GRB. To overcome this difficulty, Ramirez-Ruiz & Socrates (2005) proposed that high energy neutrinos from hot corona above the accretion disk might enhance the efficiency of energy deposition. We elucidate the disk corona model in the context of hypercritical accretion flows. From the energy balance in the disk and the corona, we can calculate the disk and coronal temperature, Td and Tc, and neutrino spectra, taking into account the neutrino cooling processes by neutrino-electron scatterings and neutrino pair productions. Th...

  8. A magnetohydrodynamic theory of coronal loop transients

    Science.gov (United States)

    Yeh, T.

    1982-01-01

    The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

  9. Periodicities in Solar Coronal Mass Ejections

    CERN Document Server

    Lou, Y Q; Fan, Z; Wang, S; Wang, J

    2003-01-01

    Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during the most recent solar maximum cycle 23 are reported here for the first time using the four-year data (February 5, 1999 to February 10, 2003) of the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). In parallel, mid-term quasi-periodicities in solar X-ray flares (class >M5.0) from the Geosynchronous Operational Environment Satellites (GOES) and in daily averages of Ap index for geomagnetic disturbances from the World Data Center (WDC) at the International Association for Geomagnetism and Aeronomy (IAGA) are also examined for the same four-year time span. Several conceptual aspects of possible equatorially trapped Rossby-type waves at and beneath the solar photosphere are discussed.

  10. Kinematical properties of coronal mass ejections

    CERN Document Server

    Temmer, Manuela

    2016-01-01

    Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun-Earth distance within a few days. Earth-directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severly affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth-directed events. This short review focusing on observational data, shows recent methods which w...

  11. Solar Eruptions: Coronal Mass Ejections and Flares

    Science.gov (United States)

    Gopalswamy, Nat

    2012-01-01

    This lecture introduces the topic of Coronal mass ejections (CMEs) and solar flares, collectively known as solar eruptions. During solar eruptions, the released energy flows out from the Sun in the form of magnetized plasma and electromagnetic radiation. The electromagnetic radiation suddenly increases the ionization content of the ionosphere, thus impacting communication and navigation systems. Flares can be eruptive or confined. Eruptive flares accompany CMEs, while confined flares hav only electromagnetic signature. CMEs can drive MHD shocks that accelerate charged particles to very high energies in the interplanetary space, which pose radiation hazard to astronauts and space systems. CMEs heading in the direction of Earth arrive in about two days and impact Earth's magnetosphere, producing geomagnetic storms. The magnetic storms result in a number of effects including induced currnts that can disrupt power grids, railroads, and underground pipelines

  12. Transverse Oscillations in a Coronal Loop Triggered by a Jet

    Science.gov (United States)

    Sarkar, S.; Pant, V.; Srivastava, A. K.; Banerjee, D.

    2016-11-01

    We detect and analyse transverse oscillations in a coronal loop, lying at the south-east limb of the Sun as seen from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The jet is believed to trigger transverse oscillations in the coronal loop. The jet originates from a region close to the coronal loop on 19 September 2014 at 02:01:35 UT. The length of the loop is estimated to be between 377 - 539 Mm. Only one complete oscillation is detected with an average period of about 32±5 min. Using magnetohydrodynamic (MHD) seismologic inversion techniques, we estimate the magnetic field inside the coronal loop to be between 2.68 - 4.5 G. The velocity of the hot and cool components of the jet is estimated to be 168 km s^{-1} and 43 km s^{-1}, respectively. The energy density of the jet is found to be greater than the energy density of the oscillating coronal loop. We therefore conclude that the jet triggered transverse oscillations in the coronal loop. To our knowledge, this is the first coronal loop seismology study using the properties of a jet propagation to trigger oscillations.

  13. Coronal loops above an Active Region - observation versus model

    CERN Document Server

    Bourdin, Philippe-A; Peter, Hardi

    2014-01-01

    We conducted a high-resolution numerical simulation of the solar corona above a stable active region. The aim is to test the field-line braiding mechanism for a sufficient coronal energy input. We also check the applicability of scaling laws for coronal loop properties like the temperature and density. Our 3D-MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the corona, where currents are induced that heat the coronal plasma by Ohmic dissipation. We compute synthetic coronal emission that we directly compare to coronal observations of the same active region taken by Hinode. In the model, coronal loops form at the same places as they are found in coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction ...

  14. PROMINENCE ACTIVATION BY CORONAL FAST MODE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Takuya [Department of Astronomy, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shibata, Kazunari, E-mail: takahashi@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2015-03-01

    An X5.4 class flare occurred in active region NOAA11429 on 2012 March 7. The flare was associated with a very fast coronal mass ejection (CME) with a velocity of over 2500 km s{sup −1}. In the images taken with the Solar Terrestrial Relations Observatory-B/COR1, a dome-like disturbance was seen to detach from an expanding CME bubble and propagated further. A Type-II radio burst was also observed at the same time. On the other hand, in extreme ultraviolet images obtained by the Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA), the expanding dome-like structure and its footprint propagating to the north were observed. The footprint propagated with an average speed of about 670 km s{sup −1} and hit a prominence located at the north pole and activated it. During the activation, the prominence was strongly brightened. On the basis of some observational evidence, we concluded that the footprint in AIA images and the ones in COR1 images are the same, that is, the MHD fast mode shock front. With the help of a linear theory, the fast mode Mach number of the coronal shock is estimated to be between 1.11 and 1.29 using the initial velocity of the activated prominence. Also, the plasma compression ratio of the shock is enhanced to be between 1.18 and 2.11 in the prominence material, which we consider to be the reason for the strong brightening of the activated prominence. The applicability of linear theory to the shock problem is tested with a nonlinear MHD simulation.

  15. The Dynamics of Coronal-Hole Boundaries

    Science.gov (United States)

    Higginson, A. K.; Antiochos, S. K.; DeVore, C. R.; Wyper, P. F.; Zurbuchen, T.

    2015-12-01

    The source of the slow solar wind at the Sun is the subject of intense debate in solar and heliospheric physics. Because the majority of the solar wind observed at Earth is slow wind, understanding its origin is essential for understanding and predicting Earth's space weather environment. In-situ and remote observations show that, compared to the fast wind, the slow solar wind corresponds to higher freeze-in temperatures, as indicated by charge-state ratios, and more corona-like elemental abundances. These results indicate that the most likely source for the slow wind is the hot plasma in the closed-field corona; however, the release mechanism for the wind from the closed-field regions is far from understood. Here we present the first fully dynamic, 3D MHD simulations of a coronal-hole boundary driven by photospheric convective flows. We determine in detail the opening and closing of coronal flux due to photospheric motions at the base of a helmet streamer. These changes should lead to the release of plasma from the closed magnetic field at the edge of the streamer. Our analysis demonstrates that the bulk of the release is due to interchange reconnection. We calculate the effective of numerical Lundquist number on the dynamics and discuss the implications of our results for theories of slow-wind origin, in particular the S-Web model. We also discuss the implications of our results for observations, in particular from the upcoming Solar Orbiter and Solar Probe Plus missions. This work was supported by the NASA SR&T and TR&T Programs.

  16. Health and imaging outcomes in axial spondyloarthritis

    NARCIS (Netherlands)

    Machado, P.M.

    2016-01-01

    This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment

  17. MHD Waves and Coronal Seismology: an overview of recent results

    CERN Document Server

    De Moortel, Ineke

    2012-01-01

    Recent observations have revealed that MHD waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology which have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfven waves and (iv) the rapidly developing topic of quasi-periodic pulsations (QPP) in solar flares.

  18. Magnetohydrodynamic waves and coronal seismology: an overview of recent results.

    Science.gov (United States)

    De Moortel, Ineke; Nakariakov, Valery M

    2012-07-13

    Recent observations have revealed that magnetohydrodynamic (MHD) waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology that have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfvén waves, and (iv) the rapidly developing topic of quasi-periodic pulsations in solar flares.

  19. Case report: pre-eruptive intra-coronal radiolucencies revisited.

    LENUS (Irish Health Repository)

    Counihan, K P

    2012-08-01

    Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.

  20. Formation of the current sheet in a coronal streamer

    CERN Document Server

    Abbo, Lucia; Lionello, Roberto; Mikić, Zoran; Riley, Pete

    2011-01-01

    The present work is on the study of a coronal streamer observed in March 2008 at high spectral and spatial resolution by the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO. On the basis of a spectroscopic analysis of the O VI doublet, the solar wind plasma parameters are inferred in the extended corona. The analysis accounts for the coronal magnetic topology, extrapolated through a 3D magneto-hydrodynamic model. The results of the analysis show indications on the formation of the current sheet, one of the source regions of the slow coronal wind.

  1. Effects of frontal and sagittal thorax attitudes in gait on trunk and pelvis three-dimensional kinematics.

    Science.gov (United States)

    Begon, Mickaël; Leardini, Alberto; Belvedere, Claudio; Farahpour, Nader; Allard, Paul

    2015-10-01

    While sagittal trunk inclinations alter upper body biomechanics, little is known about the extent of frontal trunk bending on upper body and pelvis kinematics in adults during gait and its relation to sagittal trunk inclinations. The objective was to determine the effect of the mean lateral trunk attitude on upper body and pelvis three-dimensional kinematics during gait in asymptomatic subjects. Three gait cycles were collected in 30 subjects using a motion analysis system (Vicon 612) and an established protocol. Sub-groups were formed based on the mean thorax lateral bending angle, bending side, and also sagittal tilt. These were compared based on 38 peak angles identified on pelvis, thorax and shoulder kinematics using MANOVAs. A main effect for bending side (p = 0.038) was found, especially for thorax peak angles. Statistics revealed also a significant interaction (p = 0.04993) between bending side and tilt for the thorax sagittal inclination during body-weight transfer. These results reinforce the existence of different gait patterns, which correlate upper body and pelvis motion measures. The results also suggest that frontal and sagittal trunk attitude should be considered carefully when treating a patient with impaired gait.

  2. Measuring the Reliability of Sagittal Facial Anthropometric Measurements under Soft Tissue Displacement Using a Modified Ruler

    Directory of Open Access Journals (Sweden)

    Faramarz Mojtahedzadeh

    2013-01-01

    Full Text Available Objective: Despite the current use of radiography for quantifying sagittal skeletal measurements, it is an unsuitable way for screening or epidemiologic purposes. Although not fully approved, anthropometric measurements have been suggested as a substitute, and considering displacement of soft tissues, could possibly lead to more consistent results. The purpose of this study was to evaluate the reliability of anthropometric anteroposterior facial measurements under soft tissue compression using a special ruler.Material and Methods: Anthropometric measurements were done with a specifically designed sliding ruler twice on 36 adult patients with a 14 day lag between two measurements. The ruler measured the distance between the external acoustic meatus and the nasion (Na, subnasal (Sn point and the soft tissue pogonion (Pog. The soft tissue was displaced during measurements only to the extent that the underlying hard tissue resistance was felt subjectively by each assessor. The intraclass correlation coefficient (ICC was calculated for both inter- and intra- rater measurements using SPSS software.Results: All measurements had inter- and intrarater agreements above 0.9, with only a few parameters having lower bound confidence intervals below 0.9, but more than 0.8.Conclusion: Sagittal facial anthropometric measurements under soft tissue displacement using the specific ruler are valid and reliable and could possibly aid orthodontists in chairside craniofacial assessments.

  3. Effect of back muscle strength and sagittal spinal imbalance on locomotive syndrome in Japanese men.

    Science.gov (United States)

    Hirano, Kenichi; Imagama, Shiro; Hasegawa, Yukiharu; Wakao, Norimitsu; Muramoto, Akio; Ishiguro, Naoki

    2012-07-01

    The Japanese Orthopaedic Association has proposed the term locomotive syndrome to designate a condition of individuals in high-risk groups with musculoskeletal disease who are highly likely to require nursing care. This study investigates the influence of spinal factors on locomotive syndrome in Japanese men. A total of 105 men older than 50 years were enrolled in the study. Those answering yes to least 1 of 7 categories in a self-assessment checklist for locomotive syndrome were defined as having locomotive syndrome. The authors evaluated lateral lumbar radiographs, sagittal parameters, sagittal balance using the spinal inclination angle as an index, spinal range of motion as determined with SpinalMouse (Idiag, Volkerswill, Switzerland), back muscle strength, and body mass index. Age, back muscle strength, and spinal inclination angle significantly correlated with locomotive syndrome. Multiple logistic regression analysis indicated that a decrease in back muscle strength (odds ratio, 0.964; Pmuscle strength had significant negative correlations with age and spinal inclination angle. Spinal inclination angle had significant negative correlations with back muscle strength and lumbar and total spinal range of motion and significant positive correlations with age, body mass index, sacral slope angle, and lumbar kyphosis. A decrease in back muscle strength and an increase in spinal inclination angle may be the most important risk factors for locomotive syndrome in Japanese men. Back muscle strengthening and spinal range of motion exercises could be useful for improving the symptoms of locomotive syndrome.

  4. Sagittal MR findings of L5 spondylolysis : changes of spinal canal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Cheol; Choi, Woo Suk; Kim, Eui Jong; Ryu, Kyung Nam; Oh, Joo Hyeong; Kim, Ihn Sub; Yoon, Yup [Kyunghee Univ. Hospital, Seoul (Korea, Republic of)

    1997-07-01

    To evaluate changes in the spinal canal in cases of L5 spondylolysis, as seen on sagittal MR images. We retrospectively analysed the MR findings of 27 patients suffering from L5 spondylolysis without spondylolisthesis and compared them with 100 control subjects. Spondylolysis had been confirmed by conventional radiography. On midsagittal MR images, sagittal canal ratio (SCR) was defined as midsagittal canal diameter at L5 devided by that at L1. We analysed the frequency of posterior epidural fat deposition(posterior epidural fat between the posterior margin of the dural sac and the anterior cortical margin of the spinous process on the midsagittal line), and compared this with the frequency in 100 control subjects. Mean SCR value in 27 patients with L5 spondylolysis(1.22) was significantly greater than 100 control subjects(0.96, p<0.001). Mean SCR value in 17 patients with L5 spondylolysis and posterior epidural fat deposition(1.27) was significantly higher than in nine control subjects with posterior epidural fat deposition(0.97). Posterior epidural fat deposition was more frequently indentified in patients with L5 spondylolysis(63%) than in control subjects(9%). The possibility of L5 spondylolysis is suggested when on midsaggital MR imaging, the anteroposterior diameter of the L5 spinal canal is seen to be widened and posterior epidural fat deposition is noted.

  5. Risk factors for breakage of biodegradable plate systems after bilateral sagittal split mandibular setback surgery.

    Science.gov (United States)

    Yoshioka, Izumi; Igawa, Kaori; Nagata, Jyunko; Yoshida, Maho; Baba, Takashi; Ichiki, Takeshi; Kondoh, Yudai; Takamori, Koichi; Kashima, Koji; Sakoda, Sumio

    2013-06-01

    The aim of this retrospective study was to evaluate the risk factors associated with breakage of biodegradable plate systems after bilateral sagittal split mandibular setback. We studied 169 Japanese adults (62 men, 107 women; age range 16-53 years) with deformities of the jaw diagnosed as mandibular prognathism. All patients were treated by bilateral sagittal split osteotomy (BSSO) with 2 biodegradable fixation plates and screws at the anterior mandibular ramus. We collected the following data from the medical records and radiological findings: sex; age; degree of setback; presence of asymmetry; presence of open bite; operation; design of the plate; operating time; and blood loss. Multiple logistic regression analysis was used to find the factors that were independently associated with the dependent variable: breakage of the biodegradable plate system. In 10 of the 169 patients (6%) the biodegradable plate system for the BSSO broke. Factors that influenced whether or not the biodegradable plate system fractured were if they were asymmetrical (odds ratio (OR) 5.35; P=0.02) and had an open bite (OR 5.20; P=0.02). Asymmetry or open bite was significantly associated with breaks in the biodegradable plate system. Biodegradable plates should be used only when loading is minimal.

  6. Sagittal and Frontal Plane Evaluation of the Whole Spine and Clinical Outcomes after Vertebral Fractures

    Directory of Open Access Journals (Sweden)

    A. Topalidou

    2015-01-01

    Full Text Available Although it is known that a change in any level of the spine alters biomechanics, there are not many studies to evaluate the spine as a whole in both sagittal and frontal planes. This prospective cohort study evaluates the morphology and mobility of the entire spine in patients with vertebral fractures. The Treatment Group consisted of 43 patients who underwent percutaneous balloon kyphoplasty or percutaneous balloon kyphoplasty plus fixation. The Control Group consisted of 39 healthy subjects. Spinal Mouse was used for the assessment of the curvatures and the mobility of the spine. Clinical outcomes were evaluated by Visual Analogue Scale and Oswestry Disability Index. The measurements were recorded at 15 days and 3, 6, and 12 months postoperatively. Regarding the curvatures and mobility in sagittal plane, a statistically significant increase appeared early at 3 months, for lumbar curve, spinopelvic angulation, and overall trunk inclination. In the frontal plane, most of the improvements were recorded after 6 months. Patients with osteoporotic fracture showed statistically significant lower mean value than patients with traumatic fracture. Pain and disability index showed early improvements. This study provides a comprehensive and complete picture of the functionality of the spine in patients treated with percutaneous balloon kyphoplasty.

  7. Assessment of Normal Sagittal Alignment of the Spine and Pelvis in Children and Adolescents

    Directory of Open Access Journals (Sweden)

    Hasan Ghandhari

    2013-01-01

    Full Text Available Aim. We aimed to determine spinopelvic balance in 8–19-year-old-people in order to assess pelvic and spinal parameters in sagittal view. Methods. Ninety-eight healthy students aged 8–19 years, who lived in the central parts of Tehran, were assessed. Demographic data, history of present and past diseases, height (cm, and weight (kg were collected. Each subject was examined by an orthopedic surgeon and spinal radiographs in lateral view were obtained. Eight spinopelvic parameters were measured by 2 orthopedic spine surgeons. Results. Ninety-eight subjects, among which 48 were girls (49% and 50 boys (51%, with a mean age of 13.6±2.9 years (range: 8–19 were evaluated. Mean height and weight of children were 153.6±15.6 cm and 49.9±13.1 kgs, respectively. Mean TK, LL, TT, LT, and PI of subjects were 37.1 ± 9.9°, 39.6 ± 12.4°, 7.08 ± 4.9°, 12.0 ± 5.9°, and 45.37 ± 10.7°, respectively. Conclusion. Preoperation planning for spinal fusion surgeries via applying PI seems reasonable. Predicating “abnormal” to lordosis and kyphosis values alone without considering overall sagittal balance is incorrect. Mean of SS and TK in our population is slightly less than that in Caucasians.

  8. Evidence showing the relationship between sagittal balance and clinical outcomes in surgical treatment of degenerative spinal diseases: a literature review.

    Science.gov (United States)

    Le Huec, Jean-Charles; Faundez, Antonio; Dominguez, Dennis; Hoffmeyer, Pierre; Aunoble, Stéphane

    2015-01-01

    The measure of radiographic pelvic and spinal parameters for sagittal balance analysis has gained importance in reconstructive surgery of the spine and particularly in degenerative spinal diseases (DSD). Fusion in the lumbar spine may result in loss of lumbar lordosis (LL), with possible compensatory mechanisms: decreased sacral slope (SS), increased pelvic tilt (PT) and decreased thoracic kyphosis (TK). An increase in PT after surgery is correlated with postoperative back pain. A decreased SS and/or abnormal sagittal vertical axis (SVA) after fusion have a higher risk of adjacent segment degeneration. High pelvic incidence (PI) increases the risk of sagittal imbalance after spine fusion and is a predictive factor for degenerative spondylolisthesis. Restoration of a normal PT after surgery is correlated with good clinical outcome. Therefore, there is a need for comparative prospective studies that include pre- and postoperative spinopelvic parameters and compare complication rate, degree of disability, pain and quality of life.

  9. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops

    CERN Document Server

    Al-Ghafri, Khalil Salim

    2015-01-01

    The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops namely thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function that ensures the temperature evolution of the background plasma due to radiation coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglect the magnetic field perturbation and eventually reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale much larger than the oscillation period that subsequently enables...

  10. Standing sausage modes in coronal loops with plasma flow

    CERN Document Server

    Li, Bo; Xia, Li-Dong; Yu, Hui

    2014-01-01

    Magnetohydrodynamic waves are important for diagnosing the physical parameters of coronal plasmas. Field-aligned flows appear frequently in coronal loops.We examine the effects of transverse density and plasma flow structuring on standing sausage modes trapped in coronal loops, and examine their observational implications. We model coronal loops as straight cold cylinders with plasma flow embedded in a static corona. An eigen-value problem governing propagating sausage waves is formulated, its solutions used to construct standing modes. Two transverse profiles are distinguished, one being the generalized Epstein distribution (profile E) and the other (N) proposed recently in Nakariakov et al.(2012). A parameter study is performed on the dependence of the maximum period $P_\\mathrm{max}$ and cutoff length-to-radius ratio $(L/a)_{\\mathrm{cutoff}}$ in the trapped regime on the density parameters ($\\rho_0/\\rho_\\infty$ and profile steepness $p$) and flow parameters (magnitude $U_0$ and profile steepness $u$). For e...

  11. Cyclical Variation of the Quiet Corona and Coronal Holes

    Indian Academy of Sciences (India)

    Takashi Sakurai

    2000-09-01

    Recent advances in the understanding of the quiet corona and coronal holes are reviewed. The review is based on long-term accumulation of data from eclipse observations, coronagraph observations, helium 10830 Å spectroheliograms, and X-ray observations.

  12. Jet phenomena above null points of the coronal magnetic field

    Science.gov (United States)

    Filippov, B.; Koutchmy, S.; Golub, L.

    2009-12-01

    Short-lived plasma jets of various scales, from giant X-ray jets more than 300 Mm in extent to numerous small jets with sizes typical of macrospicules, are the phenomena observed in the solar corona in extreme ultraviolet and X-ray emission. Small jets are particularly prominent in polar coronal holes. They are close neighbors of tiny bright loops and coincide in time with their sudden brightening and increase in size. The geometric shape of the jets and their location suggest that they arise near singular null points of the coronal magnetic field. These points appear in coronal holes due to the emergence of small bipolar or unipolar magnetic structures within large-scale unipolar cells. Polar jets show a distinct vertical plasma motion in a coronal hole that introduces significant momentum and mass into the solar wind flow. Investigating the dynamics of polar jets can elucidate certain details in the problem of fast solar wind acceleration.

  13. The coronal magnetic field reversal observed by the SOLARC instrument

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; SHEN YuanDeng

    2009-01-01

    High-sensitivity measurements for mapping coronal magnetic field have become possible since the recent development of infrared detection techniques. One urgent task that arises from the routine infrared observations is to interpret what the Stokes signals could indicate for coronal magnetic fields. It is the first time for us to successfully reveal the coronal field structure above a simple and stable sunspot on the photosphere using profiles of full Stokes parameters. In this paper, the author further points out the deficiency in any conclusions/judgements just based on incomplete polarization data. A magnetic flux reversal feature, observed from circular polarization data, may correspond to one or more coronal tubes with their front or farside arching apex there, more complicated than people imagined before. To exactly locate the infrared radiation sources, we need both circular and linear polarization data for an integrated analysis of them.

  14. Anticipating the Geoeffectiveness of Coronal Mass Ejections Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Coronal Mass Ejections (CMEs) are responsible for some of the most severe space weather at Earth. Major geomagnetic storms arise when CMEs carry large amounts of...

  15. Exploración del modelo coronal MHD de Uchida

    Science.gov (United States)

    Francile, C.; Castro, J. I.; Flores, M.

    We present an analysis of the MHD model of an isothermal solar corona with radially symmetrical magnetic field and gravity. The solution in the approximation "WKB" was presented by Uchida (1968). The model is ex- plored for different coronal conditions and heights of initial perturbation to study the propagation of coronal waves and reproduce the observed char- acteristics of phenomena such as Moreton waves. Finally we discuss the obtained results. FULL TEXT IN SPANISH

  16. Are Spicules the Primary Source of Hot Coronal Plasma?

    Science.gov (United States)

    Klimchuk, James A.

    2011-01-01

    The recent discovery of Type II spicules has generated considerable excitement. It has even been suggested that these ejections can account for a majority of the hot plasma observed in the corona, thus obviating the need for "coronal" heating. If this is the case, however, then there should be observational consequences. We have begun to examine some of these consequences and find reason to question the idea that spicules are the primary source of hot coronal plasma.

  17. Observing the formation of flare-driven coronal rain

    OpenAIRE

    Scullion, E.; Rouppe van der Voort, L.; Antolin, P.; Wedemeyer, S.; Vissers, G.; E. P. Kontar; Gallagher, P

    2016-01-01

    PA. GV are funded by the European Research Council under the European Union Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement nr. 291058 Flare-driven coronal rain can manifest from rapidly cooled plasma condensations near coronal loop-tops in thermally unstable post-flare arcades. We detect 5 phases that characterise the post-flare decay:heating, evaporation, conductive cooling dominance for ~120 s, radiative/ enthalpy cooling dominance for ~4700 s and finally catastrophic ...

  18. Role of T1 Pelvic Angle in Assessing Sagittal Balance in Outpatients With Unspecific Low Back Pain.

    Science.gov (United States)

    Yang, Mingyuan; Yang, Changwei; Xu, Zhengfang; Chen, Ziqiang; Wei, Xianzhao; Zhao, Jian; Shao, Jie; Zhang, Guoyou; Zhao, Yingchuan; Ni, Haijian; Bai, Yushu; Zhu, Xiaodong; Li, Ming

    2016-03-01

    The aim of the study was to explore the significance of T1 pelvic angle (TPA) for assessment of sagittal balance in a cohort of Chinese patients with unspecific low back pain. TPA has been commonly used to assess sagittal balance in adult spinal deformity. However, whether TPA could be used to assess sagittal balance in patients with unspecific low back pain effectively remains unanswered. Medical records of outpatients with unspecific low back pain who received treatment in our outpatient clinic between September 2013 and November 2014 were reviewed. Demographic data and radiographic data were collected. Correlation coefficients between TPA and other sagittal parameters were analyzed, and the intraclass correlation coefficient (ICC) analysis was performed to assess the inter- and intra-observer reliability of TPA. Patients were divided into 2 groups according to whether they were well-aligned (TPA ≤ 20°) or poorly aligned (TPA > 20°), and then demographic and sagittal parameters were compared between the 2 groups of patients. A total of 97 patients with unspecific low back pain were included in this study. The inter- and intraobserver reliability of the TPA measure had excellent agreement (ICC = 0.985 and 0.919, respectively). There were significant correlations between TPA and age, LL, PT, PI, T1SPI, SVA, and NRS (all P 5 cm in the other 5 (13.16%) patients, and of the 59 poorly aligned patients in Group B, SVA was >5 cm in 42 (71.19%) patients and ≤5 cm in the other 17 (28.81%) patients. There were significant differences in age, LL, SS, PT, PI, T1SPI, SVA, and NRS between the 2 groups of patients, but no significant difference was observed in TK and TL. TPA could be used to assess sagittal balance in outpatients with unspecific low back pain effectively.

  19. Axial force measurement for esophageal function testing

    Institute of Scientific and Technical Information of China (English)

    Flemming H Gravesen; Peter Funch-Jensen; Hans Gregersen; Asbjφrn Mohr Drewes

    2009-01-01

    The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method.

  20. Axial force measurement for esophageal function testing.

    Science.gov (United States)

    Gravesen, Flemming H; Funch-Jensen, Peter; Gregersen, Hans; Drewes, Asbjørn Mohr

    2009-01-14

    The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method.

  1. Coronal Dynamics at Recent Total Solar Eclipses

    Science.gov (United States)

    Pasachoff, J. M.; Lu, M.; Davis, A. B.; Demianski, M.; Rusin, V.; Saniga, M.; Seaton, D. B.; Lucas, R.; Babcock, B. A.; Dantowitz, R.; Gaintatzis, P.; Seeger, C. H.; Malamut, C.; Steele, A.

    2014-12-01

    Our composite images of the solar corona based on extensive imaging at the total solar eclipses of 2010 (Easter Island), 2012 (Australia), and 2013 (Gabon) reveal several coronal mass ejections and other changes in coronal streamers and in polar plumes. Our resultant spatial resolution is finer than that available in imaging from spacecraft, including that from SOHO/LASCO or STEREO. We trace the eruptions back to their footpoints on the sun using imaging from SDO and SWAP, and follow them upwards through the corona, measuring velocities. The high-resolution computer compositing by Miloslav Druckmüller and Hana Druckmüllerová (2010 and 2013) and Pavlos Gaintatzis (2012) allows comparison of our images with those taken at intervals of minutes or hours along the totality path. Williams College's 2013 eclipse expedition was supported in part by grant 9327-13 from National Geographic Society/Committee for Research and Exploration. Our work on the 2012 eclipse is supported in part by grant AGS-1047726 from Solar Terrestrial Research/NSF AGS. V.R. and M.S. were partially supported by the VEGA grant agency project 2/0098/10 and 2/0003/13 (Slovak Academy of Sciences) and Grant 0139-12 from NG/CRE, and Hana Druckmüllerová by grant 205/09/1469 of the Czech Science Foundation. M.L. was supported by Sigma Xi. C.M. was a Keck Northeast Astronomy Consortium Summer Fellow, supported at Williams College by REU/NSF grant AST-1005024. Partial support was provided by U.S. Department of Defense's ASSURE program. J.M.P. thanks Caltech's Planetary Sciences Department for hospitality. Support for D.B.S. and SWAP came from PRODEX grant C90345 managed by ESA in collaboration with the Belgian Federal Science Policy Office (BELSPO) in support of the PROBA2/SWAP mission, and from the EC's Seventh Framework Programme (FP7/2007-2013) under grant 218816 (SOTERIA project, www.soteria-space.eu). SWAP is a project of the Centre Spatial de Liège and the Royal Observatory of Belgium funded by

  2. Evolving Coronal Holes and Interplanetary Erupting Stream Disturbances

    Indian Academy of Sciences (India)

    Rajendra Shelke

    2006-06-01

    Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of enhanced density turbulence in the interplanetary medium driven by the high-speed flows of low-density plasma trailing behind for several days. Here, an attempt has been made to investigate the solar cause of erupting stream disturbances, mapped by Hewish & Bravo (1986) from interplanetary scintillation (IPS) measurements made between August 1978 and August 1979 at 81.5 MHz. The position of the sources of 68 erupting stream disturbances on the solar disk has been compared with the locations of newborn coronal holes and/or the areas that have been coronal holes previously. It is found that the occurrence of erupting stream disturbances is linked to the emergence of newcoronal holes at the eruption site on the solar disk. A coronal hole is indicative of a radial magnetic field of a predominant magnetic polarity. The newborn coronal hole emerges on the Sun, owing to the changes in magnetic field configuration leading to the opening of closed magnetic structure into the corona. The fundamental activity for the onset of an erupting stream seems to be a transient opening of pre-existing closed magnetic structures into a new coronal hole, which can support high-speed flow trailing behind the compression zone of the erupting stream for several days.

  3. Transverse oscillations in a coronal loop triggered by a jet

    CERN Document Server

    Sarkar, S; Srivastava, A K; Banerjee, D

    2016-01-01

    We detect and analyse transverse oscillations in a coronal loop, lying at the south east limb of the Sun as seen from the \\textit{{Atmospheric Imaging Assembly}} (AIA) onboard \\textit{{Solar Dynamics Observatory}} (SDO). The jet is believed to trigger transverse oscillations in the coronal loop. The jet originates from a region close to the coronal loop on 19$^{\\rm th}$ September 2014 at 02:01:35 UT. The length of the loop is estimated to be between 377-539~Mm. Only one complete oscillation is detected with an average period of about $32\\pm5$~min. Using MHD seismologic inversion techniques, we estimate the magnetic field inside the coronal loop to be between $2.68 -4.5$~G. The velocity of the hot and cool components of the jet is estimated to be 168~km~s$^{-1}$ and 43~km~s$^{-1}$, respectively. The energy density of the jet is found to be greater than the energy density of the oscillating coronal loop. Therefore, we conclude that the jet {triggered} transverse oscillations in the coronal loop. To our knowledg...

  4. The Contribution of Coronal Jets To The Solar Wind

    CERN Document Server

    Lionello, R; Titov, V S; Leake, J E; MikiĆ, Z; Linker, J A; Linton, M G

    2016-01-01

    Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulations, i.e, we use boundary conditions provided by such simulations to drive a time-dependent coronal evolution. The model includes parametric coronal heating, radiative losses, and thermal conduction, which enables us to simulate the dynamics and plasma properties of coronal jets in a more realistic manner than done so far. Here we employ these simulations to calculate the amount of mass and energy transported by coronal j...

  5. New Anomaly of the Axial-Vector Current

    Institute of Scientific and Technical Information of China (English)

    HE Han-Xin

    2001-01-01

    By computing the axial-vector current operator equation, we find the anomalous axial-vector curl equation besides the well-known anomalous axial-vector divergence equation (the Adler-Bell-Jackiw anomaly) and discuss its implication.``

  6. Reliability of the Radiographic Sagittal and Frontal Tibiotalar Alignment after Ankle Arthrodesis.

    Directory of Open Access Journals (Sweden)

    Madeleine Willegger

    Full Text Available Accurate measurement of the tibiotalar alignment is important in radiographic outcome assessment of ankle arthrodesis (AA. In studies, various radiological methods have been used to measure the tibiotalar alignment leading to facultative misinterpretation of results. However, to our knowledge, no previous study has investigated the reliability of tibiotalar alignment measurement in AA. We aimed to investigate the reliability of four different methods of measurement of the frontal and sagittal tibiotalar alignment after AA, and to further clarify the most reliable method for determining the longitudinal axis of the tibia.Thirty-eight weight bearing anterior to posterior and lateral ankle radiographs of thirty-seven patients who had undergone AA with a two screw fixation technique were selected. Three observers measured the frontal tibiotalar angle (FTTA and the sagittal tibiotalar angle (STTA using four different methods. The methods differed by the definition of the longitudinal tibial axis. Method A was defined by a line drawn along the lateral tibial border in anterior to posterior radiographs and along the posterior tibial border in lateral radiographs. Method B was defined by a line connecting two points in the middle of the proximal and the distal tibial shaft. Method C was drawn "freestyle"along the longitudinal axis of the tibia, and method D was defined by a line connecting the center of the tibial articular surface and a point in the middle of the proximal tibial shaft. Intra- and interobserver correlation coefficients (ICC and repeated measurement ANOVA were calculated to assess measurement reliability and accuracy.All four methods showed excellent inter- and intraobserver reliability for the FTTA and the STTA. When the longitudinal tibial axis is defined by connecting two points in the middle of the proximal and the distal tibial shaft, the highest interobserver reliability for the FTTA (ICC: 0.980; CI 95%: 0.966-0.989 and for the

  7. Agreement between fiber optic and optoelectronic systems for quantifying sagittal plane spinal curvature in sitting.

    Science.gov (United States)

    Cloud, Beth A; Zhao, Kristin D; Breighner, Ryan; Giambini, Hugo; An, Kai-Nan

    2014-07-01

    Spinal posture affects how individuals function from a manual wheelchair. There is a need to directly quantify spinal posture in this population to ultimately improve function. A fiber optic system, comprised of an attached series of sensors, is promising for measuring large regions of the spine in individuals sitting in a wheelchair. The purpose of this study was to determine the agreement between fiber optic and optoelectronic systems for measuring spinal curvature, and describe the range of sagittal plane spinal curvatures in natural sitting. Able-bodied adults (n = 26, 13 male) participated. Each participant assumed three sitting postures: natural, slouched (accentuated kyphosis), and extension (accentuated lordosis) sitting. Fiber optic (ShapeTape) and optoelectronic (Optotrak) systems were applied to the skin over spinous processes from S1 to C7 and used to measure sagittal plane spinal curvature. Regions of kyphosis and lordosis were identified. A Cobb angle-like method was used to quantify lordosis and kyphosis. Generalized linear model and Bland-Altman analyses were used to assess agreement. A strong correlation exists between curvature values obtained with Optotrak and ShapeTape (R(2) = 0.98). The mean difference between Optotrak and ShapeTape for kyphosis in natural, extension, and slouched postures was 4.30° (95% LOA: -3.43 to 12.04°), 3.64° (95% LOA: -1.07 to 8.36°), and 4.02° (95% LOA: -2.80 to 10.84°), respectively. The mean difference for lordosis, when present, in natural and extension postures was 2.86° (95% LOA: -1.18 to 6.90°) and 2.55° (95% LOA: -3.38 to 8.48°), respectively. In natural sitting, the mean ± SD of kyphosis values was 35.07 ± 6.75°. Lordosis was detected in 8/26 participants: 11.72 ± 7.32°. The fiber optic and optoelectronic systems demonstrate acceptable agreement for measuring sagittal plane thoracolumbar spinal curvature.

  8. Why are halo coronal mass ejections faster?

    Institute of Scientific and Technical Information of China (English)

    Qing-Min Zhang; Yang Guo; Peng-Fei Chen; Ming-De Ding; Cheng Fang

    2010-01-01

    Halo coronal mass ejections(CMEs)have been to be significantly faster than normal CMEs,which is a long-standing puzzle.In order to solve the puzzle,we first investigate the observed properties of 31 limb CMEs that clearly display loopshaped frontal loops.The observational results show a strong tendency that slower CMEs are weaker in white-light intensity.Then,we perform a Monte Carlo simulation of 20000 artificial limb CMEs that have an average velocity of~523 km s-1.The Thomson scattering of these events is calculated when they are assumed to be observed as limb and halo events,respectively.It is found that the white-light intensity of many slow CMEs becomes remarkably reduced when they turn from being viewed as a limb event to being viewed as a halo event.When the intensity is below the background solar wind fluctuation,it is assumed that they would be missed by coronagraphs.The average velocity of"detectable"halo CMEs is~922 km s-1,very close to the observed value.This also indicates that wider events are more likely to be recorded.The results soundly suggest that the higher average velocity of halo CMEs is due to that a majority of slow events and some of narrow fast events carrying less material are so faint that they are blended with the solar wind fluctuations,and therefore are not observed.

  9. Active Longitude and Coronal Mass Ejection Occurrences

    Science.gov (United States)

    Gyenge, N.; Singh, T.; Kiss, T. S.; Srivastava, A. K.; Erdélyi, R.

    2017-03-01

    The spatial inhomogeneity of the distribution of coronal mass ejection (CME) occurrences in the solar atmosphere could provide a tool to estimate the longitudinal position of the most probable CME-capable active regions in the Sun. The anomaly in the longitudinal distribution of active regions themselves is often referred to as active longitude (AL). In order to reveal the connection between the AL and CME spatial occurrences, here we investigate the morphological properties of active regions. The first morphological property studied is the separateness parameter, which is able to characterize the probability of the occurrence of an energetic event, such as a solar flare or CME. The second morphological property is the sunspot tilt angle. The tilt angle of sunspot groups allows us to estimate the helicity of active regions. The increased helicity leads to a more complex buildup of the magnetic structure and also can cause CME eruption. We found that the most complex active regions appear near the AL and that the AL itself is associated with the most tilted active regions. Therefore, the number of CME occurrences is higher within the AL. The origin of the fast CMEs is also found to be associated with this region. We concluded that the source of the most probably CME-capable active regions is at the AL. By applying this method, we can potentially forecast a flare and/or CME source several Carrington rotations in advance. This finding also provides new information for solar dynamo modeling.

  10. Multiscale Modeling of Solar Coronal Magnetic Reconnection

    Science.gov (United States)

    Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard

    2010-01-01

    Magnetic reconnection is widely believed to be the primary process by which the magnetic field releases energy to plasma in the Sun's corona. For example, in the breakout model for the initiation of coronal mass ejections/eruptive flares, reconnection is responsible for the catastrophic destabilizing of magnetic force balance in the corona, leading to explosive energy release. A critical requirement for the reconnection is that it have a "switch-on' nature in that the reconnection stays off until a large store of magnetic free energy has built up, and then it turn on abruptly and stay on until most of this free energy has been released. We discuss the implications of this requirement for reconnection in the context of the breakout model for CMEs/flares. We argue that it imposes stringent constraints on the properties of the flux breaking mechanism, which is expected to operate in the corona on kinetic scales. We present numerical simulations demonstrating how the reconnection and the eruption depend on the effective resistivity, i.e., the effective Lundquist number, and propose a model for incorporating kinetic flux-breaking mechanisms into MHO calculation of CMEs/flares.

  11. Geometric Model of a Coronal Cavity

    Science.gov (United States)

    Kucera, Therese A.; Gibson, S. E.; Ratawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; Schmidt, D. J.; Sterling, A. C.; Tripathi, D. K.; Williams, D. R.; Zhang, M.

    2010-01-01

    We observed a coronal cavity from August 8-18 2007 during a multi-instrument observing campaign organized under the auspices of the International Heliophysical Year (IHY). Here we present initial efforts to model the cavity with a geometrical streamer-cavity model. The model is based the white-light streamer mode] of Gibson et a]. (2003 ), which has been enhanced by the addition of a cavity and the capability to model EUV and X-ray emission. The cavity is modeled with an elliptical cross-section and Gaussian fall-off in length and width inside the streamer. Density and temperature can be varied in the streamer and cavity and constrained via comparison with data. Although this model is purely morphological, it allows for three-dimensional, multi-temperature analysis and characterization of the data, which can then provide constraints for future physical modeling. Initial comparisons to STEREO/EUVI images of the cavity and streamer show that the model can provide a good fit to the data. This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities

  12. Coronal activity from the ASAS eclipsing binaries

    CERN Document Server

    Szczygiel, D M; Paczynski, B; Pojmanski, G; Pilecki, B

    2008-01-01

    We combine the catalogue of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalogue, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L_X/L_bol ~ a few x 10^-4, similar to the ratio of soft X-ray to bolometric flux F_X/F_bol in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs -- stars with significant outer convection zones -- a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called "super-saturation" phenomena. Our work shows that wide-...

  13. Surface Flux Emergence and Coronal Eruption

    Science.gov (United States)

    Fang, Fang

    2016-05-01

    Among various active regions, delta-sunspots of aggregated spots of opposite polarities, are of particular interest due to their high productivity in energetic and recurrent eruptive events, such as X-class flares and homologous eruptions. We here study the formation of such complex magnetic structures by numerical simulations of magnetic flux emergence from the convection zone into the corona in an active-region scale domain. In our simulation, two pairs of bipolar sunspots form on the surface, originating from two buoyant segments of a single subsurface twisted flux rope. Expansion and rotation of the emerging fields in the two bipoles drive the two opposite polarities into each other with apparent rotating motion, producing a compact delta-sunspot with a sharp polarity inversion line (PIL). The formation of the delta-sunspot in such a realistic-scale domain produces emerging patterns similar to those formed in observations, e.g. the inverted polarity against Hale’s law, the curvilinear motion of the spot, strong transverse field with highly sheared magnetic and velocity fields at the PIL. Strong current builds up at the PIL, giving rise to reconnection, which produces a complex coronal magnetic connectivity with non-potential fields in the delta-spot overlaid by more relaxed fields connecting the two polarities at the two ends.

  14. Stellar Differential Rotation and Coronal Timescales

    CERN Document Server

    Gibb, G P S; Mackay, D H

    2014-01-01

    We investigate the timescales of evolution of stellar coronae in response to surface differential rotation and diffusion. To quantify this we study both the formation time and lifetime of a magnetic flux rope in a decaying bipolar active region. We apply a magnetic flux transport model to prescribe the evolution of the stellar photospheric field, and use this to drive the evolution of the coronal magnetic field via a magnetofrictional technique. Increasing the differential rotation (i.e. decreasing the equator-pole lap time) decreases the flux rope formation time. We find that the formation time is dependent upon the geometric mean of the lap time and the surface diffusion timescale. In contrast, the lifetime of flux ropes are proportional to the lap time. With this, flux ropes on stars with a differential rotation of more than eight times the solar value have a lifetime of less than two days. As a consequence, we propose that features such as solar-like quiescent prominences may not be easily observable on s...

  15. Potential Method of Predicting Coronal Mass Ejection

    Science.gov (United States)

    Imholt, Timothy

    2001-10-01

    Coronal Mass Ejections (CME) may be described as a blast of gas and highly charged solar mass fragments ejected into space. These ejections, when directed toward Earth, have many different effects on terrestrial systems ranging from the Aurora Borealis to changes in wireless communication. The early prediction of these solar events cannot be overlooked. There are several models currently accepted and utilized to predict these events, however, with earlier prediction of both the event and the location on the sun where the event occurs allows us to have earlier warnings as to when they will affect man-made systems. A better prediction could perhaps be achieved by utilizing low angular resolution radio telescope arrays to catalog data from the sun at different radio frequencies on a regular basis. Once this data is cataloged a better predictor for these CME’s could be found. We propose a model that allows a prediction to be made that appears to be longer than 24 hours.

  16. Are Coronal Loops Isothermal or Multithermal? Yes!

    CERN Document Server

    Schmelz, J T; Rightmire, L A; Kimble, J A; Del Zanna, G; Cirtain, J W; DeLuca, E E; Mason, H E

    2009-01-01

    Surprisingly few solar coronal loops have been observed simultaneously with TRACE and SOHO/CDS, and even fewer analyses of these loops have been conducted and published. The SOHO Joint Observing Program 146 was designed in part to provide the simultaneous observations required for in-depth temperature analysis of active region loops and determine whether these loops are isothermal or multithermal. The data analyzed in this paper were taken on 2003 January 17 of AR 10250. We used TRACE filter ratios, emission measure loci, and two methods of differential emission measure analysis to examine the temperature structure of three different loops. TRACE and CDS observations agree that Loop 1 is isothermal with Log T $=$ 5.85, both along the line of sight as well as along the length of the loop leg that is visible in the CDS field of view. Loop 2 is hotter than Loop 1. It is multithermal along the line of sight, with significant emission between 6.2 $<$ Log T $<$ 6.4, but the loop apex region is out of the CDS ...

  17. Anatomy of Depleted Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.; Manchester, W. B., IV

    2017-01-01

    We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE/SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C6+/C5+ and O7+/O6+ depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property of significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.

  18. Radio-quiet Fast Coronal Mass Ejections

    Science.gov (United States)

    Gopalswamy, N.; Aguilar-Rodriguez, E.; Kaiser, M. L.; Howard, R. A.

    2004-12-01

    Coronal mass ejections (CMEs) drive shocks in the interplanetary medium that produce type II radio emission. These CMEs are faster and wider on the average, than the general population of CMEs. However, when we start from fast (speed > 900 km/s) and wide (angular width > 60 degrees), more than half of them are not associated with radio bursts. In order to understand why these CMEs are radio quiet, we collected all the fast and wide (FW) CMEs detected by the Solar and Heliospheric Observatory (SOHO) mission's Large Angle and Spectrometric Coronagraph (LASCO) and isolated those without associated type II radio bursts. The radio bursts were identified in the dynamic spectra of the Radio and Plasma Wave (WAVES) Experiment on board the Wind spacecraft. We also checked the list against metric type II radio bursts reported in Solar Geophysical Data and isolated those without any radio emission. This exercise resulted in about 140 radio-quiet FW CMEs. We identified the source regions of these CMEs using the Solar Geophysical Data listings, cross-checked against the eruption regions in the SOHO/EIT movies. We explored a number of possibilities for the radio-quietness: (i) Source region being too far behind the limb, (ii) flare size, (iii) brightness of the CME, and (iv) the density of the ambient medium. We suggest that a combination of CME energy and the Alfven speed profile of the ambient medium is primarily responsible for the radio-quietness of these FW CMEs.

  19. Energy Release in Driven Twisted Coronal Loops

    Science.gov (United States)

    Bareford, M. R.; Gordovskyy, M.; Browning, P. K.; Hood, A. W.

    2016-01-01

    We investigate magnetic reconnection in twisted magnetic fluxtubes, representing coronal loops. The main goal is to establish the influence of the field geometry and various thermodynamic effects on the stability of twisted fluxtubes and on the size and distribution of heated regions. In particular, we aim to investigate to what extent the earlier idealised models, based on the initially cylindrically symmetric fluxtubes, are different from more realistic models, including the large-scale curvature, atmospheric stratification, thermal conduction and other effects. In addition, we compare the roles of Ohmic heating and shock heating in energy conversion during magnetic reconnection in twisted loops. The models with straight fluxtubes show similar distribution of heated plasma during the reconnection: it initially forms a helical shape, which subsequently becomes very fragmented. The heating in these models is rather uniformly distributed along fluxtubes. At the same time, the hot plasma regions in curved loops are asymmetric and concentrated close to the loop tops. Large-scale curvature has a destabilising influence: less twist is needed for instability. Footpoint convergence normally delays the instability slightly, although in some cases, converging fluxtubes can be less stable. Finally, introducing a stratified atmosphere gives rise to decaying wave propagation, which has a destabilising effect.

  20. A Catalog of Coronal "EIT Wave" Transients

    Science.gov (United States)

    Thompson, B. J.; Myers, D. C.

    2009-01-01

    Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning from 1997 March 24 and extending through 1998 June 24. The dates covered start at the beginning of regular high-cadence (more than one image every 20 minutes) observations, ending at the four-month interruption of SOHO observations in mid-1998. One hundred and seventy six events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wave fronts and associated active regions, and the speeds of the wave fronts. The measured speeds of the wave fronts varied from less than 50 to over 700 km s(exp -1) with "typical" speeds of 200-400 km s(exp -1).

  1. Magnetic resonance imaging in diffuse idiopathic skeletal hyperostosis: similarities to axial spondyloarthritis.

    Science.gov (United States)

    Arad, Uri; Elkayam, Ori; Eshed, Iris

    2017-03-31

    Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory condition that involves calcification and ossification of the spinal ligaments and entheses. While, characteristic magnetic resonance imaging (MRI) lesions of the spine in patients with axial spondyloarthritis, another enthesitis-related disease, have been described and defined, there is a paucity of information regarding the MRI findings in DISH. The aim of this study was to describe the MRI findings of patients with DISH. We collected computed tomography studies with findings characteristic of DISH and that also had corresponding and concurrent MRI studies of the spine. For each patient, sagittal T1-weighted and STIR MRI sequences were evaluated for anterior/posterior vertebral corners of bone marrow edema (BME) and fat deposition. In total, we assessed 156 vertebral units in 10 patients that had both radiographic evidence of DISH and available MRI studies of the spine. Lesions consistent with BME corners were detected in five patients, and in three of them, three separate sites were involved, a finding that is suggestive of axial spondyloarthritis (SpA) according to the ASAS/OMERACT consensus statement. Fat deposition corners were detected in eight patients and in seven of them, several sites were involved. Spinal MRI lesions that are characteristic of axial SpA were commonly observed in a cohort of patients with DISH. This bears relevance to cases with diagnostic uncertainty and may imply overlapping pathogenetic mechanisms for new bone formation in both SpA and DISH. Further study is indicated to better characterize the similarities and differences between the MRI lesions of DISH and SpA.

  2. Quantitative analysis of disc degeneration using axial T2 mapping in a percutaneous annular puncture model in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Jee Won; Kim, Su Jin [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); Kang, Heung Sik; Lee, Joon Woo [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Hong, Sung Hwan [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2016-02-15

    To evaluate T2 relaxation time change using axial T2 mapping in a rabbit degenerated disc model and determine the most correlated variable with histologic score among T2 relaxation time, disc height index, and Pfirrmann grade. Degenerated disc model was made in 4 lumbar discs of 11 rabbits (n = 44) by percutaneous annular puncture with various severities of an injury. Lumbar spine lateral radiograph, MR T2 sagittal scan and MR axial T2 mapping were obtained at baseline and 2 weeks and 4 weeks after the injury in 7 rabbits and at baseline and 2 weeks, 4 weeks, and 6 weeks after the injury in 4 rabbits. Generalized estimating equations were used for a longitudinal analysis of changes in T2 relaxation time in degenerated disc model. T2 relaxation time, disc height index and Pfirrmann grade were correlated with the histologic scoring of disc degeneration using Spearman's rho test. There was a significant difference in T2 relaxation time between uninjured and injured discs after annular puncture. Progressive decrease in T2 relaxation time was observed in injured discs throughout the study period. Lower T2 relaxation time was observed in the more severely injured discs. T2 relaxation time showed the strongest inverse correlation with the histologic score among the variables investigated (r = -0.811, p < 0.001). T2 relaxation time measured with axial T2 mapping in degenerated discs is a potential method to assess disc degeneration.

  3. Axial Super-resolution Evanescent Wave Tomography

    CERN Document Server

    Pendharker, Sarang; Newman, Ward; Ogg, Stephen; Nazemifard, Neda; Jacob, Zubin

    2016-01-01

    Optical tomographic reconstruction of a 3D nanoscale specimen is hindered by the axial diffraction limit, which is 2-3 times worse than the focal plane resolution. We propose and experimentally demonstrate an axial super-resolution evanescent wave tomography (AxSET) method that enables the use of regular evanescent wave microscopes like Total Internal Reflection Fluorescence Microscope (TIRF) beyond surface imaging, and achieve tomographic reconstruction with axial super-resolution. Our proposed method based on Fourier reconstruction achieves axial super-resolution by extracting information from multiple sets of three-dimensional fluorescence images when the sample is illuminated by an evanescent wave. We propose a procedure to extract super-resolution features from the incremental penetration of an evanescent wave and support our theory by 1D (along the optical axis) and 3D simulations. We validate our claims by experimentally demonstrating tomographic reconstruction of microtubules in HeLa cells with an axi...

  4. Axial thermal rotation of slender rods.

    Science.gov (United States)

    Li, Dichuan; Fakhri, Nikta; Pasquali, Matteo; Biswal, Sibani Lisa

    2011-05-06

    Axial rotational diffusion of rodlike polymers is important in processes such as microtubule filament sliding and flagella beating. By imaging the motion of small kinks along the backbone of chains of DNA-linked colloids, we produce a direct and systematic measurement of axial rotational diffusivity of rods both in bulk solution and near a wall. The measured diffusivities decrease linearly with the chain length, irrespective of the distance from a wall, in agreement with slender-body hydrodynamics theory. Moreover, the presence of small kinks does not affect the chain's axial diffusivity. Our system and measurements provide insights into fundamental axial diffusion processes of slender objects, which encompass a wide range of entities including biological filaments and linear polymer chains.

  5. How to diagnose axial spondyloarthritis early

    OpenAIRE

    Rudwaleit, M.; van der Heijde, D.; Khan, M.; Braun, J.; Sieper, J.

    2004-01-01

    Background: Chronic low back pain (LBP), the leading symptom of ankylosing spondylitis (AS) and undifferentiated axial spondyloarthritis (SpA), precedes the development of radiographic sacroiliitis, sometimes by many years.

  6. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been...... force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external...... documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe...

  7. SOLAR MAGNETIC ACTIVITY CYCLES, CORONAL POTENTIAL FIELD MODELS AND ERUPTION RATES

    Energy Technology Data Exchange (ETDEWEB)

    Petrie, G. J. D. [National Solar Observatory, Tucson, AZ 85719 (United States)

    2013-05-10

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  8. Solar magnetic activity cycles, coronal potential field models and eruption rates

    Science.gov (United States)

    Petrie, Gordon

    2013-07-01

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking (CACTus), Solar Eruptive Event Detection System (SEEDS), and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003-2012 than for those between 1997-2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  9. Clinical evaluation of the lateral sagittal infraclavicular block developed by MRI studies

    DEFF Research Database (Denmark)

    Koscielniak-Nielsen, Zbigniew J; Rasmussen, Henrik; Hesselbjerg, Lars;

    2005-01-01

    BACKGROUND AND OBJECTIVES: Lateral sagittal infraclavicular block by single injection has a faster performance time and causes less discomfort than does axillary block by multiple injections. This prospective, descriptive, multicenter study assessed block effectiveness, onset time, and incidence......, needle insertion depth and dorsal angle, twitch type, analgesia of the individual nerves, and incidence of adverse events and complications, as well as patient's acceptance, were recorded. RESULTS: One hundred forty-three patients (91%) had successful blocks, 12 patients required supplementary nerve...... not observed. Only 3 patients would prefer general anesthesia in the future. Finger/wrist extension may be an optimal twitch response (P = .14). CONCLUSIONS: Block effectiveness (91%) and onset time (20 minutes) were satisfactory and comparable to the vertical paracoracoid approach. The low rate of axillary...

  10. Blockade of calcitonin gene-related peptide release after superior sagittal sinus stimulation in cat

    DEFF Research Database (Denmark)

    Knight, Y E; Edvinsson, L; Goadsby, P J

    1999-01-01

    . Avitriptan and CP122,288 both have strong binding affinities for 5HT(1B/1D)receptors, but only CP122,288 is a potent inhibitor of PPE. In this study we sought to compare the effects of CP122,288 and avitriptan on jugular vein CGRP release after stimulation of the superior sagittal sinus (SSS) in the cat....... In eleven anaesthetized cats external jugular vein blood samples were analyzed by radioimmunoassay for CGRP levels in three settings: a) control, b) 1 min after SSS stimulation and c) 1 min after SSS stimulation in presence of drug. Stimulation of the SSS resulted in release of CGRP from the external...

  11. Superior Sagittal Sinus Thrombosis Presenting with Hallucinations in the Puerperium: A Case Report

    Directory of Open Access Journals (Sweden)

    Zylfije Hundozi

    2016-12-01

    Full Text Available Cerebral venous sinus thrombosis is an uncommon cause of stroke presenting with varied presentation patterns. We report a case of a 21-year-old woman with superior sagittal sinus (SSS thrombosis (SSST developing after childbirth, presenting with visual hallucinations, severe headache, and tonic-clonic seizures. Time-of-flight magnetic resonance angiography (TOF-MRA demonstrated the presence of thrombus in SSS. She was treated with low molecular weight heparin (LMWH followed by warfarin. She had excellent recovery a few weeks after admission and was regularly followed up. Although this condition can be presented with different neurological symptoms, it does not typically present with hallucinations. We suggest that CSVT should be suspected even when a patient presents with an atypical picture in a category of patients at higher risk.

  12. Influence of neck pain on cervical movement in the sagittal plane during smartphone use.

    Science.gov (United States)

    Kim, Man-Sig

    2015-01-01

    [Purpose] Smartphone use reportedly changes posture. However, how neck posture is altered in smartphone users with neck pain is unknown. This study examined changes in the posture of young adults with and without mild neck pain (MNP) when using a smartphone. [Subjects] Thirteen control subjects and 14 subjects with MNP who used smartphones were recruited. [Methods] The upper cervical (UC) and lower cervical (LC) angles in the sagittal plane were measured using an ultrasound-based motion analysis system while the seated subjects used a smartphone for 5 min. [Results] During smartphone use, the MNP group exhibited greater UC and LC flexion angles than the control group. [Conclusion] These findings suggest that young adults with MNP are more careful and more frequently utilize a neutral neck posture than young adults without MNP when using a smartphone while sitting.

  13. Emergency surgical management of traumatic superior sagittal sinus injury: An unusual case

    Directory of Open Access Journals (Sweden)

    Sudhansu Sekhar Mishra

    2012-01-01

    Full Text Available Head injuries following fall of heavy objects are not very uncommon in developing countries. However, compound depressed skull fracture with superior sagittal sinus (SSS laceration caused by a flying asbestos fragment in a stormy afternoon is an unusual mode of head injury. We report such an unusual case of compound depressed skull fracture by an asbestos fragment injuring the middle third of SSS and its successful surgical management in a 14-year-old child. The role of computed tomography (CT scan of head with 3D reconstruction is highlighted. Early steps taken in this case to check the profuse bleeding, which helped save the life of this boy is interesting to note.

  14. Moyamoya disease and sagittal sinus thrombosis in a child with Down's syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Del-Rio Camacho, G.; Leal Orozco, A.; Camino Lopez, M.; Ruiz-Moreno, M. [Dept. of Paediatrics, Fundacion Jimenez Diaz, Madrid (Spain); Perez-Higueras, A.; Al-Assir, I. [Dept. of Neuroradiology, Fundacion Jimenez Diaz, Madrid (Spain)

    2001-02-01

    A girl with Down's syndrome, moyamoya disease and sagittal sinus thrombosis is described. She was diagnosed after acute neurological deterioration by MRI and angiography. Recombinant tissue plasminogen activator (r-TPA) was injected locally to recanalise the thrombus. The patient's condition significantly improved and she was discharged. After 2 years of follow-up the child remains asymptomatic. Moyamoya syndrome and cerebral venous thrombosis should not be overlooked as a cause of acute neurological deterioration in a child with Down's syndrome. MRA appears to be a safe and accurate alternative to traditional angiography for the diagnosis of moyamoya disease. Local fibrinolysis with r-TPA is the treatment of choice for cerebral venous thrombosis due to its safety and efficacy. (orig.)

  15. Numerical simulation of axial flow compressors.

    OpenAIRE

    Jesuino Takachi Tomita

    2002-01-01

    This work deals with the numerical simulation of axial flow compressors, from design to performance prediction. The stage performance prediction uses the meanline flow properties. Stage-stacking is used to analyse a multi-stage compressor. A computer program, written in FORTRAN, was developed and is able to design an axial flow compressor given air mass flow, total pressure ratio, overall efficiency and design speed. All geometrical data relevant to the compressor performance prediction is ca...

  16. Nonperturbative Aspects of Axial Vector Vertex

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang

    2002-01-01

    It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.

  17. Analysis of the sagittal plane after surgical management for Scheuermann's disease: a view on overcorrection and the use of an anterior release.

    NARCIS (Netherlands)

    Hosman, A.J.F.; Langeloo, D.D.; Kleuver, M. de; Anderson, P.G.; Veth, R.P.H.; Slot, G.H.

    2002-01-01

    STUDY DESIGN: A historic cohort study was conducted to investigate surgical correction and sagittal alignment in 33 patients with thoracic Scheuermann's disease. OBJECTIVE: To evaluate kyphosis correction, correction loss, sagittal balance, and the effect of an anterior release. SUMMARY OF BACKGROUN

  18. ON THE RELATIONSHIP BETWEEN THE CORONAL MAGNETIC DECAY INDEX AND CORONAL MASS EJECTION SPEED

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yan; Liu Chang; Jing Ju; Wang Haimin, E-mail: yx2@njit.edu [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

    2012-12-10

    Numerical simulations suggest that kink and torus instabilities are two potential contributors to the initiation and prorogation of eruptive events. A magnetic parameter called the decay index (i.e., the coronal magnetic gradient of the overlying fields above the eruptive flux ropes) could play an important role in controlling the kinematics of eruptions. Previous studies have identified a threshold range of the decay index that distinguishes between eruptive and confined configurations. Here we advance the study by investigating if there is a clear correlation between the decay index and coronal mass ejection (CME) speed. Thirty-eight CMEs associated with filament eruptions and/or two-ribbon flares are selected using the H{alpha} data from the Global H{alpha} Network. The filaments and flare ribbons observed in H{alpha} associated with the CMEs help to locate the magnetic polarity inversion line, along which the decay index is calculated based on the potential field extrapolation using Michelson Doppler Imager magnetograms as boundary conditions. The speeds of CMEs are obtained from the LASCO C2 CME catalog available online. We find that the mean decay index increases with CME speed for those CMEs with a speed below 1000 km s{sup -1} and stays flat around 2.2 for the CMEs with higher speeds. In addition, we present a case study of a partial filament eruption, in which the decay indices show different values above the erupted/non-erupted part.

  19. Maxillomandibular Advancement in Obstructive Sleep Apnea Syndrome Patients: a Restrospective Study on the Sagittal Cephalometric Variables

    Directory of Open Access Journals (Sweden)

    Paolo Ronchi

    2013-06-01

    Full Text Available Objectives: The present retrospective study analyzes sagittal cephalometric changes in patients affected by obstructive sleep apnea syndrome submitted to maxillomandubular advancement. Material and Methods: 15 adult sleep apnea syndrome (OSAS patients diagnosed by polysomnography (PSG and treated with maxillomandubular advancement (MMA were included in this study. Pre- (T1 and postsurgical (T2 PSG studies assessing the apnea/hypopnea index (AHI and the lowest oxygen saturation (LSAT level were compared. Lateral cephalometric radiographs at T1 and T2 measuring sagittal cephalometric variables (SNA, SNB, and ANB were analyzed, as were the amount of maxillary and mandibular advancement (Co-A and Co-Pog, the distance from the mandibular plane to the most anterior point of the hyoid bone (Mp-H, and the posterior airway space (PAS.Results: Postoperatively, the overall mean AHI dropped from 58.7 ± 16 to 8.1 ± 7.8 events per hour (P < 0.001. The mean preoperative LSAT increased from 71% preoperatively to 90% after surgery (P < 0.001. All the patients in our study were successfully treated (AHI < 20 or reduced by 50%. Cephalometric analysis performed after surgery showed a statistically significant correlation between the mean SNA variation and the decrease in the AHI (P = 0.01. The overall mean SNA increase was 6°.Conclusions: Our findings suggest that the improvement observed in the respiratory symptoms, namely the apnea/hypopnea episodes, is correlated with the SNA increase after surgery. This finding may help maxillofacial surgeons to establish selective criteria for the surgical approach to sleep apnea syndrome patients.

  20. REPRODUCIBILITY AND EQUIVALENCE OF COBBMETER APPLICATION IN THE SAGITTAL EVALUATION OF THE SPINE

    Directory of Open Access Journals (Sweden)

    Luis Marchi

    Full Text Available ABSTRACT Objective: This study aims to evaluate the reliability and equivalency of using the Cobbmeter application for iPhone compared to the manual measurement method in the analysis of the sagittal spinal alignment. Methods: Cross-sectional, prospective, single-center study that had 20 panoramic radiographs of the spine in lateral view, in a neutral standing position, analyzed blindly and randomly by three independent examiners in three different times. The parameters were pelvic incidence (PI, pelvic tilt (PT and lumbar lordosis (LL. The statistical analysis was performed to measure the intraclass correlation coefficient (ICC between the two measurement methods, in addition to measuring the intra and inter-evaluators reliability. Results: For reproducibility analysis, the intra-evaluators ICC using the application resulted in a Kappa (K of 0.975 for the evaluation of pelvic incidence (PI evaluation. For pelvic tilt (PT, the K value obtained was 0.981 and the K measured for lumbar lordosis (LL analysis was 0.987. The inter-evaluators evaluation of reproducibility using the application resulted in a K value of 0.917 for PI, 0.930 for PT and 0.951 for LL. For the assessment of equivalency of methods, comparing the application to the standard method, with a goniometer and dermographic pencil, the K value found for PI was 0.873, for PV was 0.939 and for LL was 0.914. All values were significant (p<0.001 against the null hypothesis. Conclusion: This smartphone application is a valid and reliable instrument for measuring the angle involved in the sagittal balance of the spine. Furthermore, the results show that its applicability is not inferior to the manual method with goniometer and dermographic pencil.

  1. The role of debridement and reconstruction of sagittal balance in tuberculous spondylitis

    Directory of Open Access Journals (Sweden)

    Alper Gokce

    2012-01-01

    Full Text Available Background: An accepted comprehensive clinical approach to the deformed spine with tuberculous infection is still lacking. We aimed to determine the usage of a staged algorithm in the treatment of kyphotic spine with tuberculous infection and to present the clinical results of the patients treated with the help of this protocol. Materials and Methods: 54 patients (28 females, 26 males with a mean age of 39.2 (22-76 years. Preoperative, early postoperative, and followup clinical and radiologic results were evaluated retrospectively. The patients were classified into Kaplan A (kyphotic deformity 60°. They were operated by posterior instrument with anterior debridment (Kaplan A, debridment with anterior bone grafting (Kaplan B and anterior column resection and bone grafting in Kaplan C. Results: Tuberculous involvement were seen at more than one level in 40 patients and paraspinal abscess were detected in 31. Preoperative focal kyphotic deformity was reconstructed with an average of 19 (9-38 degrees. Twenty-six patients had neurologic compromise with different severities and 12 of them improved after the surgical intervention. Improvement in work ability and pain status was detected in 52% and 61% of the patients, respectively. Wound complications responding to medical care were detected in nine patients. Initial kyphotic deformity was found as an important parameter in selecting the surgical procedure. Conclusion: Regarding resected amount of infected osseous material, as planned preoperatively, have resulted with better concordance between anterior and posterior column heights and better sagittal alignment. We could correct kyphosis and improve sagittal balance with staged algorithm as used by us.

  2. A dynamic finite element analysis of human foot complex in the sagittal plane during level walking.

    Science.gov (United States)

    Qian, Zhihui; Ren, Lei; Ding, Yun; Hutchinson, John R; Ren, Luquan

    2013-01-01

    The objective of this study is to develop a computational framework for investigating the dynamic behavior and the internal loading conditions of the human foot complex during locomotion. A subject-specific dynamic finite element model in the sagittal plane was constructed based on anatomical structures segmented from medical CT scan images. Three-dimensional gait measurements were conducted to support and validate the model. Ankle joint forces and moment derived from gait measurements were used to drive the model. Explicit finite element simulations were conducted, covering the entire stance phase from heel-strike impact to toe-off. The predicted ground reaction forces, center of pressure, foot bone motions and plantar surface pressure showed reasonably good agreement with the gait measurement data over most of the stance phase. The prediction discrepancies can be explained by the assumptions and limitations of the model. Our analysis showed that a dynamic FE simulation can improve the prediction accuracy in the peak plantar pressures at some parts of the foot complex by 10%-33% compared to a quasi-static FE simulation. However, to simplify the costly explicit FE simulation, the proposed model is confined only to the sagittal plane and has a simplified representation of foot structure. The dynamic finite element foot model proposed in this study would provide a useful tool for future extension to a fully muscle-driven dynamic three-dimensional model with detailed representation of all major anatomical structures, in order to investigate the structural dynamics of the human foot musculoskeletal system during normal or even pathological functioning.

  3. A dynamic finite element analysis of human foot complex in the sagittal plane during level walking.

    Directory of Open Access Journals (Sweden)

    Zhihui Qian

    Full Text Available The objective of this study is to develop a computational framework for investigating the dynamic behavior and the internal loading conditions of the human foot complex during locomotion. A subject-specific dynamic finite element model in the sagittal plane was constructed based on anatomical structures segmented from medical CT scan images. Three-dimensional gait measurements were conducted to support and validate the model. Ankle joint forces and moment derived from gait measurements were used to drive the model. Explicit finite element simulations were conducted, covering the entire stance phase from heel-strike impact to toe-off. The predicted ground reaction forces, center of pressure, foot bone motions and plantar surface pressure showed reasonably good agreement with the gait measurement data over most of the stance phase. The prediction discrepancies can be explained by the assumptions and limitations of the model. Our analysis showed that a dynamic FE simulation can improve the prediction accuracy in the peak plantar pressures at some parts of the foot complex by 10%-33% compared to a quasi-static FE simulation. However, to simplify the costly explicit FE simulation, the proposed model is confined only to the sagittal plane and has a simplified representation of foot structure. The dynamic finite element foot model proposed in this study would provide a useful tool for future extension to a fully muscle-driven dynamic three-dimensional model with detailed representation of all major anatomical structures, in order to investigate the structural dynamics of the human foot musculoskeletal system during normal or even pathological functioning.

  4. Age-related changes in cervical sagittal range of motion and alignment.

    Science.gov (United States)

    Park, Moon Soo; Moon, Seong-Hwan; Lee, Hwan-Mo; Kim, Tae-Hwan; Oh, Jae Keun; Nam, Ji Hoon; Riew, K Daniel

    2014-08-01

    Study Design Retrospective cohort study. Objective To compare sagittal cervical range of motion (ROM) and alignment in young versus middle-aged adults. Methods One hundred four asymptomatic adults were selected randomly out of 791 subjects who underwent lateral cervical radiographs in neutral, flexion, and extension positions. They were divided into two groups: young (age 20 to 29, 52 people) and middle-aged adults (age 50 to 59, 52 people). We determined the ROMs of upper cervical (occipital-C2 angle), midcervical (C2-C7 angle), and cervicothoracic spine (cervicosternal angle). We compared the alignment differences of the two groups by calculating the distances between C2 and C7 plumb lines, and C2 central-offset distance. Results In neutral position, there was no significant difference between young and middle-aged adults. However, in flexion, C2-C7 angle, distance between C2-C7 plumb lines, and C2 central-offset distance decreased with age. In extension, C2-C7 angle and C2 central-offset distance decreased with age. During flexion and extension, midcervical ROM and the range of C2 central-offset distance decreased in the middle-aged group. However, there was no difference between the two age groups in the ROM of the upper cervical and the cervicothoracic regions during flexion and extension. Conclusion We found that, despite of the presence of age-related cervical alignment changes, the only difference between the two groups was in the sagittal ROM of the midcervical spine during flexion and extension. Only the ROM of the midcervical spine appears to change significantly, consistent with findings that these levels are most likely to develop both symptomatic and asymptomatic degenerative changes.

  5. Wave propagation in axially moving periodic strings

    Science.gov (United States)

    Sorokin, Vladislav S.; Thomsen, Jon Juel

    2017-04-01

    The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drives for diesel engines by capturing both their spatial periodicity and axial motion. The Method of Varying Amplitudes is employed in the analysis. It is shown that the compound wave traveling in the axially moving periodic string comprises many components with different frequencies and wavenumbers. This is in contrast to non-moving periodic structures, for which all components of the corresponding compound wave feature the same frequency. Due to this "multi-frequency" character of the wave motion, the conventional notion of frequency band-gaps appears to be not applicable for the moving periodic strings. Thus, for such structures, by frequency band-gaps it is proposed to understand frequency ranges in which the primary component of the compound wave attenuates. Such frequency band-gaps can be present for a moving periodic string, but only if its axial velocity is lower than the transverse wave speed, and, the higher the axial velocity, the narrower the frequency band-gaps. The revealed effects could be of potential importance for applications, e.g. they indicate that due to spatial inhomogeneity, oscillations of axially moving periodic chains always involve a multitude of frequencies.

  6. An Unbroken Axial Vector Current Conservation Law

    CERN Document Server

    Sharafiddinov, Rasulkhozha S

    2015-01-01

    The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space i...

  7. Magnetic resonance diagnosis of posterior horn tears of the lateral meniscus using a thin axial plane: the zip sign - a preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Savoye, P.Y.; Ravey, J.N.; Dubois, C.; Barbier, L.P.; Ferretti, G. [CHU Grenoble, Clinique Universitaire de Radiologie et d' Imagerie Medicale, B.P 217, Grenoble Cedex 09 (France); Courvoisier, A.; Saragaglia, D. [CHU Grenoble, Clinique Universitaire de Chirurgie Orthopedique et Traumatologique, Grenoble (France)

    2011-01-15

    The ''zip'' sign is a newly described form of meniscal tear progressing from the distal insertion of menisco-femoral ligaments (MFLs) through the lateral meniscal wall; the tear occurs during anterior cruciate ligament (ACL) rupture. The purpose of this study was to evaluate the zip sign on knee MRI within the context of ACL injuries. From a series of 261 MR examinations for acute knee injury, we selected 97 patients with both MR and arthroscopic data for a retrospective blinded review. The zip sign was defined on axial thin MR sections as a straight line from the distal insertion of MFLs in association with five sagittal images lateral to the posterior cruciate ligament (PCL) where the MFLs were identified. Sensitivity and specificity in detecting lateral meniscal tears before and after having defined the zip sign were calculated. Sensitivity in detecting the tears of the posterior horn of the lateral meniscus (PHLM) reached 87.5% (CI 0.68-0.97) after zip sign criteria were defined. The zip sign has excellent inter-observer agreement, K > 0.90. The zip sign indicates a lesion at the insertion site of MFLs into the PHLM on thin axial images associated with sagittal MR sections that may improve MR sensitivity in detecting PHLM tears. (orig.)

  8. Natural sagittal spino-pelvic alignment in boys and girls before, at and after the adolescent growth spurt

    NARCIS (Netherlands)

    Schlösser, Tom; Vincken, Koen L.; Rogers, Kenneth; Castelein, RM; Shah, Suken A.

    2015-01-01

    Adolescent idiopathic scoliosis occurs far more often in girls than in boys, and its initiation and progression normally takes place around the adolescent growth spurt. Despite extensive research into the topic, no solid explanation for both well-known phenomena has been offered. The sagittal profil

  9. Björk-Jarabak cephalometric analysis on CBCT synthesized cephalograms with different dentofacial sagittal skeletal patterns

    Directory of Open Access Journals (Sweden)

    Yalil Augusto Rodriguez-Cardenas

    2014-12-01

    Full Text Available OBJECTIVE: The objective of this study was to evaluate the Björk and Jabarak cephalometric analysis generated from cone-beam computed tomography (CBCT synthesized lateral cephalograms in adults with different sagittal skeletal patterns.METHODS: The sample consisted of 46 CBCT synthesized cephalograms obtained from patients between 16 and 40 years old. A Björk and Jarabak cephalometric analysis among different sagittal skeletal classes was performed. Analysis of variance (ANOVA, multiple range test of Tukey, Kruskal-Wallis test, and independent t-test were used as appropriate.RESULTS: In comparison to the standard values: Skeletal Class III had increased gonial and superior gonial angles (P < 0.001. This trend was also evident when sex was considered. For Class I males, the sella angle was decreased (P = 0.041, articular angle increased (P = 0.027 and gonial angle decreased (P = 0.002; whereas for Class III males, the gonial angle was increased (P = 0.012. For Class I females, the articular angle was increased (P = 0.029 and the gonial angle decreased (P = 0.004. Björk's sum and Björk and Jabarak polygon sum showed no significant differences. The facial biotype presented in the three sagittal classes was mainly hypodivergent and neutral.CONCLUSIONS: In this sample, skeletal Class III malocclusion was strongly differentiated from the other sagittal classes, specifically in the mandible, as calculated through Björk and Jarabak analysis.

  10. Transpalatal screw traction: a simple technique for the management of sagittal fractures of the maxilla and palate.

    Science.gov (United States)

    Ma, D; Guo, X; Yao, H; Chen, J

    2014-12-01

    Sagittal fractures of the maxilla and palate are uncommon in clinical practice. Current methods for the management of such fractures have advantages and limitations. The authors present the simple and practical technique of bilateral transpalatal screw traction to manage this fracture type.

  11. Long-lasting neurosensory disturbance following advancement of the retrognathic mandible : distraction osteogenesis versus bilateral sagittal split osteotomy

    NARCIS (Netherlands)

    Wijbenga, J. G.; Verlinden, C. R. A.; Jansma, J.; Becking, A. G.; Stegenga, B.

    2009-01-01

    Neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) is the most common complication after bilateral sagittal split osteotomy (BSSO) and distraction osteogenesis (DO) of the retrognathic mandible. It is suggested that the risk is lower after DO than after BSSO. This retrospective stud

  12. Anterior or posterior sagittal anorectoplasty without colostomy for low-type anorectal malformation: how to get a better outcome?

    NARCIS (Netherlands)

    Kuijper, C.F.; Aronson, D.C.

    2010-01-01

    BACKGROUND/PURPOSE: Usually, anorectal malformations (ARM) are treated in 2 or 3 stages for fear of disturbed wound healing and subsequent damage to the anal sphincter complex. The aim of this study was to assess the feasibility, safety, advantages, and follow-up of an anterior or posterior sagittal

  13. Distraction osteogenesis versus bilateral sagittal split osteotomy for advancement of the retrognathic mandible : a review of the literature

    NARCIS (Netherlands)

    Schreuder, W. H.; Jansma, J.; Bierman, M. W. J.; Vissink, A.

    2007-01-01

    Bilateral sagittal split osteotomy (BSSO) and distraction osteogenesis (DO) are the most common techniques currently applied to surgically correct mandibular retrognathia. It is the responsibility of the maxillofacial surgeon to determine the optimal treatment option in each individual case. The aim

  14. Analysis of sagittal balance using spinopelvic parameters in ankylosing spondylitis patients treated with vertebral column decancellation surgery.

    Science.gov (United States)

    Lin, Bin; Zhang, Wen-Bin; Cai, Tao-yi; Lu, Cheng-Wu; Zhou, Qin; Huang, Zhuanzhi; Yu, Hui

    2015-09-01

    This study was designed to explore the change of spinopelvic parameters after vertebral column decancellation (VCD) for the management of thoracolumbar kyphosis secondary to ankylosing spondylitis (AS). Forty-two AS patients including thirty-six males and six females with thoracolumbar kyphosis, who underwent VCD from April 2005 to June 2012 in our hospital, were retrospectively reviewed. A series of spinopelvic parameters including thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), pelvic tilt (PT) and sagittal vertical axis (SVA) measured on preoperative and postoperative free-standing radiographs were obtained and analyzed. Also clinical assessments were performed with the Oswestry disability index (ODI) and the Bath Ankylosing Spondylitis Activity and Function Index (BASDAI and BASFI) so as to seek correlations between radiological parameters and symptoms. Except for pelvic incidence (PI), significant difference was found in all radiological spinopelvic parameters between the preoperative and follow-up values. Furthermore, there was significant improvement in the clinical assessment parameters ODI, BASDAI and BASFI, which all correlated significantly with the postoperative pelvic tilt (PT). The results of this study show that posterior VCD is an effective option to manage sagittal imbalance in AS. In the current series, patients improving LL and PT were found to achieve good clinical outcomes. Overall, our findings show that it is important to quantify sagittal spinopelvic parameters and promote sagittal balance in the surgery for AS.

  15. Correlations between sagittal plane kinematics and landing impact force during single-leg lateral jump-landings

    Science.gov (United States)

    Aizawa, Junya; Ohji, Shunsuke; Koga, Hideyuki; Masuda, Tadashi; Yagishita, Kazuyoshi

    2016-01-01

    [Purpose] The correlations of peak vertical ground reaction force and sagittal angles during single-leg lateral jump-landing with noncontact anterior cruciate ligament injury remain unknown. This study aimed to clarify the correlations between kinematics and impact force during lateral jump-landing. [Subjects and Methods] Twenty active males were included in the analysis. A sagittal-view movie camera and force plate were time synchronized. Trunk and lower extremity sagittal angles were measured 100 ms before initial contact and at peak vertical ground reaction force. Peak vertical ground reaction force, time between initial contact and peak vertical ground reaction force, and loading rate were calculated. [Results] The mean sagittal angle was 40.7° ± 7.7° for knee flexion during the flight phase and 16.4° ± 6.3° for pelvic anterior inclination during the landing phase. The mean peak vertical ground reaction force was four times the body weight. The median time to peak vertical ground reaction force was 63.8 ms. The knee flexion during the flight phase and pelvic anterior inclination angles during the landing phase were related to the peak vertical ground reaction force. [Conclusion] Increasing knee flexion and decreasing pelvic anterior inclination might reduce the impact during single-leg lateral jump-landing. PMID:27630422

  16. A comparison of the oblique sagittal view obtained by magnetic resonance imaging and the intraoperative findings of vascular compression in cases of trigeminal neuralgia and hemifacial spasm

    Energy Technology Data Exchange (ETDEWEB)

    Nagaseki, Yoshishige; Horikoshi, Tohru; Omata, Tomohiro; Ueno, Takehiko; Uchida, Mikito; Nukui, Hideaki (Yamanashi Medical Coll., Tamaho (Japan)); Sasaki, Hideo; Tsuji, Reizou

    1992-06-01

    We show how neurosurgical planning can benefit from the better visualization of the precise vascular compression of the nerves provided by the oblique sagittal and gradient-echo method (OS-GR image) using magnetic resonance images (MRI) and by comparing these results with the findings of microvascular decompression. The scans of 5 patients with trigeminal neuralgia (TN) and 18 with hemifacial spasm (HFS) were analysed for the presence and appearance of the vascular compression of the nerves; all these 23 patients were operated on. Imaging sequences consisted of an OS-GR image (TR/TE: 200/20, 3-mm-thick slice) cut along each nerve shown by the axial view, which was scanned at the angle of 105 degrees taken between the dorsal line of the brain stem and the line corresponding to the pontmedullary junction. The rate of correspondence between the OS-GR images and the intraoperative findings was 80% in the TN's and 89% in the HFS's. In all these OS-GR images, the vascular compressions of the REZ of the trigeminal or facial nerve were well visualized as curvilinear high-intensity lines and/or spots. Furthermore, the relationship between the vascular compressions and nerves could be foreseen preoperatively in 40% of the TN's and in 55.6% of the HFS's. It is concluded that OS-GR images obtained by means of MRI may serve as useful planning aids prior to microvascular decompression for cases of TN and HFS because of the corresponding operative view along the approach. (author).

  17. Forecasting Coronal Mass Ejections from Vector Magnetograms

    Science.gov (United States)

    Falconer, D. A.; Moore, R. L.; Gary, G. A.; Six, N. Frank (Technical Monitor)

    2002-01-01

    In a 17 vector magnetogram study of 12 bipolar active regions (Falconer, Moore, & Gary, 2002, ApJ in press), we correlated four quantitative global magnetic measures with the Coronal Mass Ejections (CME) productivity of the active region. The global measures included a measure of active region size, the total magnetic flux phi and three measures of an active region global nonpotentiality 1) the net current (I (sub N)), 2) the length of the strong-shear, strong-field main neutral line (L(sub SS)) and 3) and the normalized twist (alpha = muIN/PHI). The CME productivity was determined from YOHKOH/SXT observations, Geostationary Operational Environmental Satellite (GOES), and when possible Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment (SOHO/LASCO) observations within 12 days of the day of the magnetogram. We found that the three measures of global nonpotentiality (I(sub N), L(sub SS), alpha) were all well correlated (greater than 99% confidence level) with an active region's CME productivity. The sample size was to small to confirm if there was a statistical significant correlation of the globally nonscientist measures with future CME activity (i.e. from the date of the magnetogram forward). We are doubling our sample, and will report on the statistical significance of global nonpotentiality as a predictor of future CME productivity. The new active regions are all from the first year of the upgraded MSFC vector magnetograms. This work, is funded by NSF through the Space Weather Program, by NASA through the Living with the Star, Targeted Research and Technology, and by NASA Solar Physics Supporting Research and Technology Program. The upgrade to the MSFC vector magnetograph was supported by the High Energy Solar Spectroscopic Imager (HESSI) mission.

  18. MAGNETIC FLUX SUPPLEMENT TO CORONAL BRIGHT POINTS

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chaozhou; Huang, Zhenghua; Xia, Lidong; Li, Bo; Fu, Hui; Jiao, Fangran; Hou, Zhenyong [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China); Madjarska, Maria S., E-mail: z.huang@sdu.edu.cn [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom)

    2016-02-10

    Coronal bright points (BPs) are associated with magnetic bipolar features (MBFs) and magnetic cancellation. Here we investigate how BP-associated MBFs form and how the consequent magnetic cancellation occurs. We analyze longitudinal magnetograms from the Helioseismic and Magnetic Imager to investigate the photospheric magnetic flux evolution of 70 BPs. From images taken in the 193 Å passband of the Atmospheric Imaging Assembly (AIA) we dermine that the BPs’ lifetimes vary from 2.7 to 58.8 hr. The formation of the BP MBFs is found to involve three processes, namely, emergence, convergence, and local coalescence of the magnetic fluxes. The formation of an MBF can involve more than one of these processes. Out of the 70 cases, flux emergence is the main process of an MBF buildup of 52 BPs, mainly convergence is seen in 28, and 14 cases are associated with local coalescence. For MBFs formed by bipolar emergence, the time difference between the flux emergence and the BP appearance in the AIA 193 Å passband varies from 0.1 to 3.2 hr with an average of 1.3 hr. While magnetic cancellation is found in all 70 BPs, it can occur in three different ways: (I) between an MBF and small weak magnetic features (in 33 BPs); (II) within an MBF with the two polarities moving toward each other from a large distance (34 BPs); (III) within an MBF whose two main polarities emerge in the same place simultaneously (3 BPs). While an MBF builds up the skeleton of a BP, we find that the magnetic activities responsible for the BP heating may involve small weak fields.

  19. Gender differences in sagittal standing alignment before pubertal peak growth: the importance of subclassification and implications for spinopelvic loading.

    Science.gov (United States)

    Dolphens, Mieke; Cagnie, Barbara; Vleeming, Andry; Vanderstraeten, Guy; Danneels, Lieven

    2013-12-01

    The aim of this study was to analyze gender differences in sagittal standing alignment at pre-peak height velocity age thereby applying a scientifically sound and practically oriented classification scheme for overall standing balance. The study population consisted of healthy boys (n = 639) and girls (n = 557) before pubertal peak growth. During subjects' habitual standing, sagittal plane measures of the spine, pelvis and lower limbs were collected using a clinical screening protocol. With each subject classified as one of three postural types (neutral, sway-back, or leaning-forward), differences in sagittal plane alignment were analyzed between sexes. The results revealed clear differences between genders in each of the postural types. Within the neutral and sway-back postural subgroups, boys presented more forward inclination of the trunk, more thoracic kyphosis and more pelvis backtilt compared with girls. Within the leaning-forward category, girls displayed more forward trunk lean, less thoracic kyphosis and more pelvic anteversion. A state of lumbar segmental hyperextension appeared to exist in female leaning-forward subjects. Our results reveal for the first time that sagittal standing alignment is different between prepubescent boys and girls when subjects are appropriately subclassified, and conversely represent a 'wash-out effect' when pooled. When the classification system is applied, gender-specificity in gravity line position is suggested, implying gender-related differences in lever arms and thus load. Present findings may add to our understanding of gender-specific biomechanical challenges posed by habitual posture, and may shed new light on sagittal standing alignment as a possible contributory factor in developmental spinal-pelvic disorders.

  20. Comparison of the Sagittal Spine Lordosis by Supine Computed Tomography and Upright Conventional Radiographs in Patients with Spinal Trauma

    Directory of Open Access Journals (Sweden)

    Samy Bouaicha

    2014-01-01

    Full Text Available Study Design. Retrospective data analysis. Objective. To compare the sagittal lordosis of the lumbar spine by supine computed tomography (CT and upright conventional radiographs. Summary of Background Data. There is sparse data about position and modality dependent changes of radiographic measurements in the sagittal lumbar spine. Methods. The anatomical and functional Cobb angles of the thoracolumbar spine in 153 patients with spinal injury were measured by conventional upright sagittal radiographs and supine CT scans. Patients were assigned either to group A (n=101, with radiologically confirmed vertebral fractures, or to group B (n=52, without any osseous lesions. The interchangeability of the two imaging modalities was calculated using a ±3° and 5° range of acceptance. Results. Group A showed a mean intraindividual difference of −3.8° for both the anatomical and the functional Cobb angle. Only 25.7% and 27.7% of the 101 patients showed a difference within the tolerated ±3° margin. Using the ±5° limits, only 46 and 47 individuals fell within the acceptable range, respectively. In the patients in group B, the mean intraindividual difference was −2.1° for the anatomical and −1.5° for the functional Cobb angle. Of the 52 patients, only 14 and 13 patients, respectively demonstrated an intraindividual difference within ±3°. With regard to a threshold of ±5°, both the functional and anatomical values were within the defined margins in only 25 (48% patients. Conclusion. The use of supine CT measurements as a baseline assessment of the sagittal lordosis of the injured thoracolumbar spine does not appear to be appropriate when upright conventional sagittal plane radiographs are used for follow-up measurements.

  1. Standing Kink modes in three-dimensional coronal loops

    Energy Technology Data Exchange (ETDEWEB)

    Pascoe, D. J.; De Moortel, I., E-mail: dpascoe@mcs.st-andrews.ac.uk [School of Mathematics and Statistics, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom)

    2014-04-01

    So far, the straight flux tube model proposed by Edwin and Roberts is the most commonly used tool in practical coronal seismology, in particular, to infer values of the (coronal) magnetic field from observed, standing kink mode oscillations. In this paper, we compare the period predicted by this basic model with three-dimensional (3D) numerical simulations of standing kink mode oscillations, as the period is a crucial parameter in the seismological inversion to determine the magnetic field. We perform numerical simulations of standing kink modes in both straight and curved 3D coronal loops and consider excitation by internal and external drivers. The period of oscillation for the displacement of dense coronal loops is determined by the loop length and the kink speed, in agreement with the estimate based on analytical theory for straight flux tubes. For curved coronal loops embedded in a magnetic arcade and excited by an external driver, a secondary mode with a period determined by the loop length and external Alfvén speed is also present. When a low number of oscillations is considered, these two periods can result in a single, non-resolved (broad) peak in the power spectrum, particularly for low values of the density contrast for which the two periods will be relatively similar. In that case (and for this particular geometry), the presence of this additional mode would lead to ambiguous seismological estimates of the magnetic field strength.

  2. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops

    Indian Academy of Sciences (India)

    K. S. Al-Ghafri

    2015-06-01

    The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops, namely, thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function, that ensures the temperature evolution of the background plasma due to radiation, coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglecting the magnetic field perturbation and, eventually, reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale, much larger than the oscillation period that subsequently enables using the WKB theory to study the properties of standing wave. The governing equation describing the time-dependent amplitude of waves is obtained and solved analytically. The analytically derived solutions are numerically evaluated to give further insight into the evolution of the standing acoustic waves. We find that the plasma cooling gives rise to a decrease in the amplitude of oscillations. In spite of the reduction in damping rate caused by rising the cooling, the damping scenario of slow standing MHD waves strongly increases in hot coronal loops.

  3. Surgical Management of Vertex Epidural Hematoma Straddling the Superior Sagittal Sinus%顶部跨上矢状窦硬膜外血肿的外科治疗策略探讨

    Institute of Scientific and Technical Information of China (English)

    韩瑞璋; 苏国军; 于烽; 赵保; 叶晶亮; 李斌; 张建忠

    2012-01-01

    Objective: To investigate the diagnosis and surgical treatment strategies of vertex epidural hematoma (VEDH) straddling the superior sagittal sinus and improve its clinical outcome. Methods: The clinical data, surgical procedures and the therapeutic effects in 27 cases of vertex epidural hematoma after brain injury admitted in our hospital from January 2002 and October 2011 were retrospectively analyzed. Results: According to GOS, 15 cases of conservative treatment all recovered well; in 12 cases of craniotomy, 7 cases recovered well, moderate disability was found in 1 case, severe disability was found in 1 case, plant survival was found in 1 case, 2 cases died. All patients had skull X-ray or CT scan hematoma region or coronal suture fracture or diastasis of the sagittal suture, and patients in operation group were confirmed by surgery, the superior sagittal sinus rupture was found in 2 cases. The prognosis of patients with Simple vertex fracture was usually better than those associated with superior sagittal sinus torn. Conclusions: VEDH is an unusual disease in clinic, progresses quickly, so correctly grasping its diagnosis and surgery indications are helpful to improve the prognosis of those patients%目的:探讨顶部跨上矢状窦硬膜外血肿的诊断和外科治疗策略,提高其临床治疗效果.方法:回顾分析2002年1月~2011年10月我院收治的27例颅脑创伤后发生的跨上矢状窦硬膜外血肿病例的临床资料、手术方法,总结分析其治疗效果.结果:按GOS治疗结果评定,保守治疗的15例患者均恢复良好;开颅手术的12例患者中,7例恢复良好,1例中残,1例重残,1例植物生存,2例死亡.全组病人均经头颅X线或CT检查提示血肿区域有骨折或冠状缝或矢状缝分离,并经手术证实,其中伴有上矢状窦破裂2例.单纯骨折不伴有矢状窦损伤者手术效果较好,而伴有矢状窦撕裂者预后较差.结论:顶叶跨上矢状窦硬膜外血肿临床少见,病情

  4. Multidetector CT of Locally Invasive Advanced Gastric Cancer: Value of Oblique Coronal Reconstructed Images for the Assessment of Local Invasion

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jin Hee; Kim, Ah Yong; Kim, Hye Jin; Yook, Jeong Hwan; Yu, Eun Sil; Jang, Yoon Jin; Park, Seong Ho; Shin, Yong Moon; Ha, Hyun Kwon [Asan Medical Center, Seoul (Korea, Republic of)

    2010-01-15

    To evaluate the diagnostic value of oblique coronal reconstructed CT images to determine the local invasion of advanced gastric cancer (AGC). Thirty-four consecutive patients, who were suspected to have locally invasive advanced gastric cancer (more than T3 stage) on a preoperative MDCT scan and underwent a diagnostic or curative laparotomy, were enrolled in this study. Two reviewers performed an independent blind review of three series of MDCT images in random order; axial (AXI), conventional coronal (CCI), and oblique coronal (OCI) (parallel to long axis of gastric body and pancreas) images. In assessing the local invasion, the reader's confidence for the local invasion of AGC was graded using a five point scale (1 = definitely negative, 5 = definitely positive: T4). With surgical findings and histopathological proofs as reference standards, the diagnostic performance of the three different plans of CT images was employed for the verification of local invasion of AGC on a preoperative CT scan using the receiver operating characteristic (ROC) method. Agreements between the two reviewers were analyzed using weighted kappa statistics. Results: In 19 out of 34 patients, local invasion was confirmed surgically or histopathologically (13 pancreas invasion, 6 liver invasion, 4 major vascular invasion, 3 colon and mesocolon invasion, and 2 spleen invasion). The diagnostic performance of OCI was superior to AXI or CCI in the local invasion of AGC. The differences in the area under the curve of AXI (0.770 {+-} 0.087, 0.700 {+-} 0.094), CCI (0.884 {+-} 0.058, 0.958 {+-} 0.038), and OCI (0.954 {+-} 0.050, 0.956 {+-} 0.049), were statistically significant for both reviewers. Inter-observer agreement was excellent for OCI ({kappa}= .973), which was greater than CCI (({kappa}= .839), and AXI (({kappa}= .763). On a CT scan, OCI might be a useful imaging technique in evaluating locally invasive advanced gastric cancer.

  5. Optimization of residual heat removal pump axial thrust and axial bearing

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  6. Axial super-resolution evanescent wave tomography

    Science.gov (United States)

    Pendharker, Sarang; Shende, Swapnali; Newman, Ward; Ogg, Stephen; Nazemifard, Neda; Jacob, Zubin

    2016-12-01

    Optical tomographic reconstruction of a 3D nanoscale specimen is hindered by the axial diffraction limit, which is 2-3 times worse than the focal plane resolution. We propose and experimentally demonstrate an axial super-resolution evanescent wave tomography (AxSET) method that enables the use of regular evanescent wave microscopes like Total Internal Reflection Fluorescence Microscope (TIRF) beyond surface imaging, and achieve tomographic reconstruction with axial super-resolution. Our proposed method based on Fourier reconstruction achieves axial super-resolution by extracting information from multiple sets of three-dimensional fluorescence images when the sample is illuminated by an evanescent wave. We propose a procedure to extract super-resolution features from the incremental penetration of an evanescent wave and support our theory by 1D (along the optical axis) and 3D simulations. We validate our claims by experimentally demonstrating tomographic reconstruction of microtubules in HeLa cells with an axial resolution of $\\sim$130 nm. Our method does not require any additional optical components or sample preparation. The proposed method can be combined with focal plane super-resolution techniques like STORM and can also be adapted for THz and microwave near-field tomography.

  7. Axial super-resolution evanescent wave tomography.

    Science.gov (United States)

    Pendharker, Sarang; Shende, Swapnali; Newman, Ward; Ogg, Stephen; Nazemifard, Neda; Jacob, Zubin

    2016-12-01

    Optical tomographic reconstruction of a three-dimensional (3D) nanoscale specimen is hindered by the axial diffraction limit, which is 2-3 times worse than the focal plane resolution. We propose and experimentally demonstrate an axial super-resolution evanescent wave tomography method that enables the use of regular evanescent wave microscopes like the total internal reflection fluorescence microscope beyond surface imaging and achieve a tomographic reconstruction with axial super-resolution. Our proposed method based on Fourier reconstruction achieves axial super-resolution by extracting information from multiple sets of 3D fluorescence images when the sample is illuminated by an evanescent wave. We propose a procedure to extract super-resolution features from the incremental penetration of an evanescent wave and support our theory by one-dimensional (along the optical axis) and 3D simulations. We validate our claims by experimentally demonstrating tomographic reconstruction of microtubules in HeLa cells with an axial resolution of ∼130  nm. Our method does not require any additional optical components or sample preparation. The proposed method can be combined with focal plane super-resolution techniques like stochastic optical reconstruction microscopy and can also be adapted for THz and microwave near-field tomography.

  8. Reducing axial mixing in flotation columns

    Energy Technology Data Exchange (ETDEWEB)

    Al Taweel, A.M.; Ramadan, A.M. [Technical Univ. of Nova Scotia, Halifax (Canada). Chemical Engineering Dept.; Moharam, M.R.; Hassan, T.A. [Al Azhar Univ., Cairo (Egypt); El Mofty, S.M. [Cairo Univ., Giza (Egypt)

    1995-10-01

    The axial mixing characteristics of a pilot-scale flotation column were investigated with the objective of identifying means to mitigate the extent of axial mixing that adversely affects its grade/recovery performance. A wide range of design and operating conditions wa investigated and the experimental results, obtained using the dynamic response method, were analyzed using three axial mixing models. The dynamic response of the column can best be described using the axial dispersion model. The results obtained suggest that the value of the axial dispersion coefficient, E{sub L}, can be significantly reduced by judicial selection of hydrodynamic conditions and/or the use of column inserts that suppress the onset of hydrodynamic instabilities inherent to the operation of conventional flotation columns. Up to 40% reduction in the value of E{sub L} was thus obtained by using spargers that produce more uniform bubble sizes, while up to 30% reductions were obtained by controlling the residual frother concentration. 33 refs., 7 figs.

  9. Characteristics of EUV coronal jets observed with STEREO/SECCHI

    CERN Document Server

    Nistico, G; Patsourakos, S; Zimbardo, G

    2009-01-01

    In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterisation of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet events commonly interpreted as a small-scale (about 35 arcsec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its looptops, and 12 lambda-type jet events commonly interpreted as reconnection with the amb...

  10. Transverse, Propagating Velocity Perturbations in Solar Coronal Loops

    CERN Document Server

    De Moortel, I; Wright, A N; Hood, A W

    2015-01-01

    This short review paper gives an overview of recently observed transverse, propagating velocity perturbations in coronal loops. These ubiquitous perturbations are observed to undergo strong damping as they propagate. Using 3D numerical simulations of footpoint-driven transverse waves propagating in a coronal plasma with a cylindrical density structure, in combination with analytical modelling, it is demonstrated that the observed velocity perturbations can be understood in terms of coupling of different wave modes in the inhomogeneous boundaries of the loops. Mode coupling in the inhomogeneous boundary layers of the loops leads to the coupling of the transversal (kink) mode to the azimuthal (Alfven) mode, observed as the decay of the transverse kink oscillations. Both the numerical and analytical results show the spatial profile of the damped wave has a Gaussian shape to begin with, before switching to exponential decay at large heights. In addition, recent analysis of CoMP (Coronal Multi-channel Polarimeter)...

  11. Flux Rope Formation Preceding Coronal Mass Ejection Onset

    CERN Document Server

    Green, L M

    2009-01-01

    We analyse the evolution of a sigmoidal (S shaped) active region toward eruption, which includes a coronal mass ejection (CME) but leaves part of the filament in place. The X-ray sigmoid is found to trace out three different magnetic topologies in succession: a highly sheared arcade of coronal loops in its long-lived phase, a bald-patch separatrix surface (BPSS) in the hours before the CME, and the first flare loops in its major transient intensity enhancement. The coronal evolution is driven by photospheric changes which involve the convergence and cancellation of flux elements under the sigmoid and filament. The data yield unambiguous evidence for the existence of a BPSS, and hence a flux rope, in the corona prior to the onset of the CME.

  12. Polarisation of microwave emission from reconnecting twisted coronal loops

    CERN Document Server

    Gordovskyy, Mykola; Kontar, Eduard

    2016-01-01

    Magnetic reconnection and particle acceleration due to the kink instability in twisted coronal loops can be a viable scenario for confined solar flares. Detailed investigation of this phenomenon requires reliable methods for observational detection of magnetic twist in solar flares, which may not be possible solely through extreme UV and soft X-ray thermal emission. The gradient of microwave polarisation across flaring loops can serve as one of the detection criteria. The aim of this study is to investigate the effect of magnetic twist in flaring coronal loops on the polarisation of gyro-synchrotron microwave emission, and determine whether microwave emission polarisation could provide a means for observational detection. We use time-dependent magnetohydrodynamic and test-particle models, developed using LARE3D and GCA codes to investigate twisted coronal loops relaxing following the kink-instability, and calculate synthetic microwave emission maps (I and V Stokes components) using GX simulator. It is found t...

  13. A data driven kinetic approach to coronal heating

    CERN Document Server

    Toutountzi, A; Isliker, H; Moraitis, K; Georgoulis, M; Chintzoglou, G

    2016-01-01

    Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Several one-dimensional hydrodynamical models have been developed over the last decade, using simple approaches for the way energy is deposited and transported in the coronal plasma, namely by inserting 'nanoflares' in the form of 'hot spots' at random sites and times. Our aim in this work is to investigate the problem from a different perspective. With the help of a nonlinear force-free extrapolation method we reconstruct the coronal magnetic field of a well-studied solar active region using an observed photospheric vector magnetogram of the region as the required boundary condition. We then determine the locations, energy contents, and volumes of unstable areas within the active-region corona. These areas include strong gradients in the magnetic field and are naturally connected to three-dimensional current sheets. The statistical distributions of these volumes, their fractal structure and correspondin...

  14. Coronal Loop Evolution Observed with AIA and Hi-C

    Science.gov (United States)

    Mulu-Moore, Fana; Winebarger, A.; Cirtain, J.; Kobayashi, K.; Korreck, K.; Golub, L.; Kuzin. S.; Walsh, R.; DeForest, C.; DePontieu, B.; Weber, M.

    2012-01-01

    Despite much progress toward understanding the dynamics of the solar corona, the physical properties of coronal loops are not yet fully understood. Recent investigations and observations from different instruments have yielded contradictory results about the true physical properties of coronal loops. In the past, the evolution of loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this poster we discuss the first results of loop analysis comparing AIA and Hi-C data. We find signatures of cooling in a pixel selected along a loop structure in the AIA multi-filter observations. However, unlike previous studies, we find that the cooling time is much longer than the draining time. This is inconsistent with previous cooling models.

  15. Influence of coronal holes on CMEs in causing SEP events

    Institute of Scientific and Technical Information of China (English)

    Cheng-Long Shen; Jia Yao; Yu-Ming Wang; Pin-Zhong Ye; Xue-Pu Zhao; Shui Wang

    2010-01-01

    The issue of the influence of coronal holes(CHs)on coronal mass ejections(CMEs)in causing solar energetic particle(SEP)events is revisited.It is a continuation and extension of our previous work,in which no evident effects of CHs on CMEs in generating SEPs were found by statistically investigating 56 CME events.This result is consistent with the conclusion obtained by Kahler in 2004.We extrapolate the coronal magnetic field,define CHs as the regions consisting of only open magnetic field lines and perform a similar analysis on this issue for 76 events in total by extending the study interval to the end of 2008.Three key parameters,CH proximity,CH area and CH relative position,are involved in the analysis.The new result confirms the previous conclusion that CHs did not show any evident effect on CMEs in causing SEP events.

  16. Ultraviolet Spectroscopic Observations of Coronal Streamers in the SOHO Era

    Indian Academy of Sciences (India)

    Leonard Strachan

    2008-03-01

    Measurements made with the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory can be used to determine physical parameters in the solar corona such as hydrogen and ion kinetic temperatures, electron densities, and absolute elemental abundances. Hydrogen and ion outflow velocities can be determined by combining the UV spectroscopic measurements with white light polarized brightness measurements. These combined measurements can be used to reveal physical characteristics of coronal streamers. To date we have studied plasma properties, such as the variation of plasma outflows in quiescent streamers, primarily in classic helmet streamers at solar minimum. Outflows have not been observed in the centers of coronal streamers suggesting that these are closed magnetic field regions.We propose to study all of the coronal streamers in the UVCS synoptic dataset in order to investigate different types of streamers and their long-term evolution.

  17. Characterizing the Properties of Coronal Magnetic Null Points

    Science.gov (United States)

    Barnes, Graham; DeRosa, Marc; Wagner, Eric

    2015-08-01

    The topology of the coronal magnetic field plays a role in a wide range of phenomena, from Coronal Mass Ejections (CMEs) through heating of the corona. One fundamental topological feature is the null point, where the magnetic field vanishes. These points are natural sites of magnetic reconnection, and hence the release of energy stored in the magnetic field. We present preliminary results of a study using data from the Helioseismic and Magnetic Imager aboard NASA's Solar Dynamics Observatory to characterize the properties and evolution of null points in a Potential Field Source Surface model of the coronal field. The main properties considered are the lifetime of the null points, their distribution with height, and how they form and subsequently vanish.This work is supported by NASA/LWS Grant NNX14AD45G, and by NSF/SHINE grant 1357018.

  18. Determination of coronal temperatures from electron density profiles

    CERN Document Server

    Lemaire, J F

    2011-01-01

    The most popular method for determining coronal temperatures is the scale-height-method (shm). It is based on electron density profiles inferred from White Light (WL) brightness measurements of the corona during solar eclipses. This method has been applied to several published coronal electron density models. The calculated temperature distributions reach a maximum at r > 1.3 RS, and therefore do not satisfy one of the conditions for applying the shm method. Another method is the hydrostatic equilibrium method (hst), which enables coronal temperature distributions to be determined, providing solutions to the hydrostatic equilibrium equation. The temperature maximas using the hst method are almost equal to those obtained using the shm method, but the temperature peak is always at significantly lower altitude when the hst-method is used than when the shm-method is used. A third and more recently developed method, dyn, can be used for the same published electron density profiles. The temperature distributions ob...

  19. The Nature of CME-Flare Associated Coronal Dimming

    CERN Document Server

    Cheng, J X

    2016-01-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect properties of CMEs in the early phase of its eruption. In this study, we analyze the event of flare, CME, and coronal dimming on December 26, 2011. We use the data from the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatories (SDO) for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 onboard the Solar Terrestrial Relations Observatories to obtain the height and velocity of the associated CMEs observed at the limb. We also measure magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons,...

  20. Examining the Properties of Jets in Coronal Holes

    Science.gov (United States)

    Gaulle, Owen; Adams, Mitzi L.; Tennant, A. F.

    2012-01-01

    We examined both X-ray and Magnetic field data in order to determine if there is a correlation between emerging magnetic flux and the production of Coronal jets. It was proposed that emerging flux can be a trigger to a coronal jet. The jet is thought to be caused when local bipoles reconnect or when a region of magnetic polarity emerges through a uniform field. In total we studied 15 different jets that occurred over a two day period starting 2011-02-27 00:00:00 UTC and ending 2011-02-28 23:59:55 UTC. All of the jets were contained within a coronal hole that was centered on the disk. Of the 15 that we studied 6 were shown to have an increase of magnetic flux within one hour prior to the creation of the jet and 10 were within 3 hours before the event.

  1. Damping of Slow Magnetoacoustic Waves in an Inhomogeneous Coronal Plasma

    Indian Academy of Sciences (India)

    Nagendra Kumar; Pradeep Kumar; Shiv Singh; Anil Kumar

    2008-03-01

    We study the propagation and dissipation of slow magnetoacoustic waves in an inhomogeneous viscous coronal loop plasma permeated by uniform magnetic field. Only viscosity and thermal conductivity are taken into account as dissipative processes in the coronal loop. The damping length of slow-mode waves exhibit varying behaviour depending upon the physical parameters of the loop in an active region AR8270 observed by TRACE. The wave energy flux associated with slow magnetoacoustic waves turns out to be of the order of 106 erg cm-2 s-1 which is high enough to replace the energy lost through optically thin coronal emission and the thermal conduction belowto the transition region. It is also found that only those slow-mode waves which have periods more than 240 s provide the required heating rate to balance the energy losses in the solar corona. Our calculated wave periods for slow-mode waves nearly match with the oscillation periods of loop observed by TRACE.

  2. Photospheric and coronal magnetic fields in six magnetographs. I. Consistent evolution of the bashful ballerina

    Science.gov (United States)

    Virtanen, Ilpo; Mursula, Kalevi

    2016-06-01

    Aims: We study the long-term evolution of photospheric and coronal magnetic fields and the heliospheric current sheet (HCS), especially its north-south asymmetry. Special attention is paid to the reliability of the six data sets used in this study and to the consistency of the results based on these data sets. Methods: We use synoptic maps constructed from Wilcox Solar Observatory (WSO), Mount Wilson Observatory (MWO), Kitt Peak (KP), SOLIS, SOHO/MDI, and SDO/HMI measurements of the photospheric field and the potential field source surface (PFSS) model. Results: The six data sets depict a fairly similar long-term evolution of magnetic fields and the heliospheric current sheet, including polarity reversals and hemispheric asymmetry. However, there are time intervals of several years long, when first KP measurements in the 1970s and 1980s, and later WSO measurements in the 1990s and early 2000s, significantly deviate from the other simultaneous data sets, reflecting likely errors at these times. All of the six magnetographs agree on the southward shift of the heliospheric current sheet (the so-called bashful ballerina phenomenon) in the declining to minimum phase of the solar cycle during a few years of the five included cycles. We show that during solar cycles 20-22, the southward shift of the HCS is mainly due to the axial quadrupole term, reflecting the stronger magnetic field intensity at the southern pole during these times. During cycle 23 the asymmetry is less persistent and mainly due to higher harmonics than the quadrupole term. Currently, in the early declining phase of cycle 24, the HCS is also shifted southward and is mainly due to the axial quadrupole as for most earlier cycles. This further emphasizes the special character of the global solar field during cycle 23.

  3. The Search for Stellar Coronal Mass Ejections

    Science.gov (United States)

    Villadsen, Jacqueline; Hallinan, Gregg; Monroe, Ryan; Bourke, Stephen; Starburst Program Team

    2017-01-01

    Coronal mass ejections (CMEs) may dramatically impact habitability and atmospheric composition of planets around magnetically active stars, including young solar analogs and many M dwarfs. Theoretical predictions of such effects are limited by the lack of observations of stellar CMEs. My thesis addresses this gap through a search for the spectral and spatial radio signatures of CMEs on active M dwarfs.Solar CMEs produce radio bursts with a distinctive spectral signature, narrow-band plasma emission that drifts to lower frequency as a CME expands outward. To search for analogous events on nearby stars, I worked on system design, software, and commissioning for the Starburst project, a wideband single-baseline radio interferometry backend dedicated to stellar observations. In addition, I led a survey of nearby active M dwarfs with the Karl G. Jansky Very Large Array (JVLA), detecting 12 bright (>10 mJy) radio bursts in 58 hours. This survey’s ultra-wide bandwidth (0.23-6.0 GHz) dynamic spectroscopy, unprecedented for stellar observations, revealed diverse behavior in the time-frequency plane. Flare star UV Ceti produced complex, luminous events reminiscent of brown dwarf aurorae; AD Leo sustained long-duration, intense, narrow-band "storms"; and YZ CMi emitted a burst with substructure with rapid frequency drift, resembling solar Type III bursts, which are attributed to electrons moving at speeds of order 10% of the speed of light.To search for the spatial signature of CMEs, I led 8.5-GHz observations with the Very Long Baseline Array simultaneous to 24 hours of the JVLA survey. This program detected non-thermal continuum emission from the stars in all epochs, as well as continuum flares on AD Leo and coherent bursts on UV Ceti, enabling measurement of the spatial offset between flaring and quiescent emission.These observations demonstrate the diversity of stellar transients that can be expected in time-domain radio surveys, especially with the advent of large low

  4. Kinematics and amplitude evolution of global coronal extreme ultraviolet waves

    Institute of Scientific and Technical Information of China (English)

    Ting Li; Jun Zhang; Shu-Hong Yang; Wei Liu

    2012-01-01

    With the observations of the Solar-Terrestrial Relations Observatory (STEREO) and the Solar Dynamics Observatory (SDO),we analyze in detail the kinematics of global coronal waves together with their intensity amplitudes (so-called "perturbation profiles").We use a semi-automatic method to investigate the perturbation profiles of coronal waves.The location and amplitude of the coronal waves are calculated over a 30° sector on the sphere,where the wave signal is strongest.The position with the strongest perturbation at each time is considered as the location of the wave front.In all four events,the wave velocities vary with time for most of their lifetime,up to 15 min,while in the event observed by the Atmospheric Imaging Assembly there is an additional early phase with a much higher velocity.The velocity varies greatly between different waves from 216 to 440 km s-1.The velocity of the two waves initially increases,subsequently decreases,and then increases again.Two other waves show a deceleration followed by an acceleration.Three categories of amplitude evolution of global coronal waves are found for the four events.The first is that the amplitude only shows a decrease.The second is that the amplitude initially increases and then decreases,and the third is that the amplitude shows an orderly increase,a decrease,an increase again and then a decrease.All the extreme ultraviolet waves show a decrease in amplitude while propagating farther away,probably because the driver of the global coronal wave (coronal mass ejection) is moving farther away from the solar surface.

  5. SIMULATIONS OF SOLAR JETS CONFINED BY CORONAL LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Wyper, P. F. [Oak Ridge Associated Universities, Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); DeVore, C. R., E-mail: peter.f.wyper@nasa.gov, E-mail: c.richard.devore@nasa.gov [Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)

    2016-03-20

    Coronal jets are collimated, dynamic events that occur over a broad range of spatial scales in the solar corona. In the open magnetic field of coronal holes, jets form quasi-radial spires that can extend far out into the heliosphere, while in closed-field regions the jet outflows are confined to the corona. We explore the application of the embedded-bipole model to jets occurring in closed coronal loops. In this model, magnetic free energy is injected slowly by footpoint motions that introduce twist within the closed dome of the jet source region, and is released rapidly by the onset of an ideal kink-like instability. Two length scales characterize the system: the width (N) of the jet source region and the footpoint separation (L) of the coronal loop that envelops the jet source. We find that both the conditions for initiation and the subsequent dynamics are highly sensitive to the ratio L/N. The longest-lasting and most energetic jets occur along long coronal loops with large L/N ratios, and share many of the features of open-field jets, while smaller L/N ratios produce shorter-duration, less energetic jets that are affected by reflections from the far-loop footpoint. We quantify the transition between these behaviors and show that our model replicates key qualitative and quantitative aspects of both quiet Sun and active-region loop jets. We also find that the reconnection between the closed dome and surrounding coronal loop is very extensive: the cumulative reconnected flux at least matches the total flux beneath the dome for small L/N, and is more than double that value for large L/N.

  6. Progresses in the treatment of coronal shear fractures of the capitellum%肱骨小头冠状面骨折治疗进展

    Institute of Scientific and Technical Information of China (English)

    姜刚强; 李海峰; 阮狄克

    2013-01-01

    Coronal shear fractures of the capitellum are uncommon elbow fractures, and the major injury mechanism is that axial extrusion forces from the radius were transmitted to the capitellum. Computerized tomography ( CT ) examination plays an important role in preoperative assessment of fractures and surgical plan-making. Dubberley classiifcation is usually used to direct the surgical treatment of fractures and judge the healing. Most of such fractures belong to intra-articular fractures, so the effects of conservative treatment are not good, and the incidence of postoperative complications such as avascular necrosis and joint stiffness is higher. Open reduction and internal ifxation ( ORIF ) is considered to be an ideal plan in the treatment of coronal shear fractures of the capitellum. Posterior and lateral approaches are commonly used in the treatment of such fractures. But currently, the choice of internal ifxation screws remains controversial. The effects of resection of fracture fragments are satisfactory in the treatment of coronal shear fractures with trochlea of humerus not involved. Minimally invasive arthroscopic surgery provides a new train of thought for the treatment of fractures. Elbow arthroplasty and ORIF combined with external ifxator can be used in the treatment of special type fractures. Functional exercise in the early stage after the operation plays an important role for the elbow joint function recovery.

  7. Coronal seismology waves and oscillations in stellar coronae

    CERN Document Server

    Stepanov, Alexander; Nakariakov, Valery M

    2012-01-01

    This concise and systematic account of the current state of this new branch of astrophysics presents the theoretical foundations of plasma astrophysics, magneto-hydrodynamics and coronal magnetic structures, taking into account the full range of available observation techniques -- from radio to gamma. The book discusses stellar loops during flare energy releases, MHD waves and oscillations, plasma instabilities and heating and charged particle acceleration. Current trends and developments in MHD seismology of solar and stellar coronal plasma systems are also covered, while recent p

  8. Automatic measurement of orbital volume in unilateral coronal synostosis

    DEFF Research Database (Denmark)

    Dahl, Vedrana Andersen; Einarsson, Gudmundur; Darvann, Tron Andre;

    2016-01-01

    Premature fusion of the coronal suture on one side of the calvaria (unilateral coronal synostosis, UCS) results in asymmetric craniofacial development and the deformation of the orbits. Often this necessitates surgery, where CT scanning is employed to obtain measures of the bony orbit...... segmentations. We obtain similar measures, as well as high Dice scores, compared to the experts. The run time for the proposed approach with a prototype implementation is around 3 minutes on a standard laptop, making the method suitable for rapid evaluation of orbital volume in UCS....

  9. Improving the lattice axial vector current

    Energy Technology Data Exchange (ETDEWEB)

    Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ. (Australia). CSSM, Dept. of Physics

    2015-11-15

    For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or one-link axial vector current whose divergence exactly satisfies a lattice Ward identity, involving the pseudoscalar density and a number of irrelevant operators. We check in one-loop lattice perturbation theory with SLiNC fermion and gauge plaquette action that this is indeed the case including order O(a) effects. Including these operators the axial Ward identity remains renormalisation invariant. First preliminary results of a nonperturbative check of the Ward identity are also presented.

  10. Axial flow positive displacement worm gas generator

    Science.gov (United States)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement engine has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first, second, and third sections of a core assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first, second, and third twist slopes in the first, second, and third sections respectively. The first twist slopes are less than the second twist slopes and the third twist slopes are less than the second twist slopes. A combustor section extends axially downstream through at least a portion of the second section.

  11. Axial symmetry and conformal Killing vectors

    CERN Document Server

    Mars, M; Mars, Marc; Senovilla, Jose M.M.

    1993-01-01

    Axisymmetric spacetimes with a conformal symmetry are studied and it is shown that, if there is no further conformal symmetry, the axial Killing vector and the conformal Killing vector must commute. As a direct consequence, in conformally stationary and axisymmetric spacetimes, no restriction is made by assuming that the axial symmetry and the conformal timelike symmetry commute. Furthermore, we prove that in axisymmetric spacetimes with another symmetry (such as stationary and axisymmetric or cylindrically symmetric spacetimes) and a conformal symmetry, the commutator of the axial Killing vector with the two others mush vanish or else the symmetry is larger than that originally considered. The results are completely general and do not depend on Einstein's equations or any particular matter content.

  12. Atlanto-axial infection after acupuncture.

    Science.gov (United States)

    Robinson, A; Lind, C R P; Smith, R J; Kodali, V

    2015-12-11

    A 67-year-old man presented with neck cellulitis following acupuncture for cervical spondylosis. Blood cultures were positive for methicillin-sensitive Staphylococcus aureus. Increased neck pain and bacteraemia prompted MRI, which showed atlanto-axial septic arthritis without signs of infection of the tissues between the superficial cellulitic area and the atlanto-axial joint, thus making direct extension of infection unlikely. It is more likely that haematogenous spread of infection resulted in seeding in the atlanto-axial joint, with the proximity of the arthritis and acupuncture site being coincidental. Acupuncture is a treatment option for some indolent pain conditions. As such, acupuncture services are likely to be more frequently utilised. A history of acupuncture is rarely requested by the admitting doctor and seldom offered voluntarily by the patient, especially where the site of infection due to haematogenous spread is distant from the needling location. Awareness of infectious complications following acupuncture can reduce morbidity through early intervention.

  13. Improving the lattice axial vector current

    CERN Document Server

    Horsley, R; Perlt, H; Rakow, P E L; Schierholz, G; Schiller, A; Zanotti, J M

    2015-01-01

    For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or one-link axial vector current whose divergence exactly satisfies a lattice Ward identity, involving the pseudoscalar density and a number of irrelevant operators. We check in one-loop lattice perturbation theory with SLiNC fermion and gauge plaquette action that this is indeed the case including order $O(a)$ effects. Including these operators the axial Ward identity remains renormalisation invariant. First preliminary results of a nonperturbative check of the Ward identity are also presented.

  14. Male and female runners demonstrate different sagittal plane mechanics as a function of static hamstring flexibility

    Directory of Open Access Journals (Sweden)

    D. S. Blaise Williams III

    2015-10-01

    Full Text Available ABSTRACTBackground:Injuries to runners are common. However, there are many potential contributing factors to injury. While lack of flexibility alone is commonly related to injury, there are clear differences in hamstring flexibility between males and females.Objective: To compare the effect of static hamstring length on sagittal plane mechanics between male and female runners.Method: Forty subjects (30.0±6.4 years participated and were placed in one of 4 groups: flexible males (n=10, inflexible males (n=10, flexible females (n=10, and inflexible females (n=10. All subjects were free of injury at the time of data collection. Three-dimensional kinematics and kinetics were collected while subjects ran over ground across 2 force platforms. Sagittal plane joint angles and moments were calculated at the knee and hip and compared with a 2-way (sex X flexibility ANOVA (α=0.05.Results: Males exhibited greater peak knee extension moment than females (M=2.80±0.47, F=2.48±0.52 Nm/kg*m, p=0.05 and inflexible runners exhibited greater peak knee extension moment than flexible runners (In=2.83±0.56, Fl=2.44±0.51 Nm/kg*m, p=0.01. For hip flexion at initial contact, a significant interaction existed (p<0.05. Flexible females (36.7±7.4º exhibited more hip flexion than inflexible females (27.9±4.6º, p<0.01 and flexible males (30.1±9.5º, p<0.05. No differences existed for knee angle at initial contact, peak knee angle, peak hip angle, or peak hip moment.Conclusion: Hamstring flexibility results in different mechanical profiles in males and females. Flexibility in the hamstrings may result in decreased moments via active or passive tension. These differences may have implications for performance and injury in flexible female runners.

  15. Axial loaded MRI of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Saifuddin, A. E-mail: asaifuddin@aol.com; Blease, S.; MacSweeney, E

    2003-09-01

    Magnetic resonance imaging is established as the technique of choice for assessment of degenerative disorders of the lumbar spine. However, it is routinely performed with the patient supine and the hips and knees flexed. The absence of axial loading and lumbar extension results in a maximization of spinal canal dimensions, which may in some cases, result in failure to demonstrate nerve root compression. Attempts have been made to image the lumbar spine in a more physiological state, either by imaging with flexion-extension, in the erect position or by using axial loading. This article reviews the literature relating to the above techniques.

  16. Axial Nucleon form factors from lattice QCD

    CERN Document Server

    Alexandrou, C; Carbonell, J; Constantinou, M; Harraud, P A; Guichon, P; Jansen, K; Korzec, T; Papinutto, M

    2010-01-01

    We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length $L=2.1$ fm and $L=2.8$ fm. Cut-off effects are investigated using three different values of the lattice spacings, namely $a=0.089$ fm, $a=0.070$ fm and $a=0.056$ fm. The nucleon axial charge is obtained in the continuum limit and chirally extrapolated to the physical pion mass enabling comparison with experiment.

  17. Optimization of Axial Intensity Point Spread Function

    Institute of Scientific and Technical Information of China (English)

    WANG Haifeng; GAN Fuxi; CHEN Zhongyu

    2001-01-01

    It is known that for the converged laser beam, the axial intensity distribution corresponds to a Gaussian curve, that is, the intensity on the focal plane is the peak intensity. When it defocuses, the intensity would decrease rapidly. In optical data storage, for instance, we expect the intensity within a certain distance to be almost equal. In this paper, we propose to use a pure phase superresolution apodizer to optimize the axial intensity distribution of the converged laser beam and at the same time improve the resolution. The intensity point spread function remains almost identical in a wide range within the focal depth.

  18. «FLARES» IN AXIAL SPONDYLOARTHRITIS

    Directory of Open Access Journals (Sweden)

    Sh. F. Erdes

    2016-01-01

    Full Text Available The clear definition of the concept of «flare in axial spondyloarthritis» is of paramount importance for clinical trials and routine practice in particular. It will be able to unify the characteristics of outcomes over a particular period of time on the one hand and to standardize therapeutic approaches on the other. On 4 February 2016, the journal Annals of Rheumatic Diseases published the on-line paper «Preliminary definitions of 'flare' in axial spondyloarthritis, based on pain, BASDAI and ASDAS-CRP: an ASAS initiative» by L. Gossec et al., which was devoted to this topic.

  19. Clinical and radiographic evaluation of a computer-generated guiding device in bilateral sagittal split osteotomies.

    Science.gov (United States)

    Abdel-Moniem Barakat, Ahmed; Abou-ElFetouh, Adel; Hakam, Maha Mohammed; El-Hawary, Hesham; Abdel-Ghany, Khaled Mahmoud

    2014-07-01

    The bilateral sagittal split osteotomy (BSSO) is one of the main orthognathic surgery procedures used for managing skeletal mandibular excess, deficiency or asymmetry. It is known to be a technique-sensitive procedure with high reported incidences of inferior alveolar nerve injury, bad splits and post-surgical relapse. With the increasing use of computer-assisted techniques in orthognathic surgery, the accurate transfer of the virtual plan to the operating room is currently a subject of research. This study evaluated the efficacy of computer-generated device at maintaining the planned condylar position and minimizing inferior alveolar nerve injury during BSSO. The device was used in 6 patients who required isolated mandibular surgery for correction of their skeletal deformities. Clinical evaluation showed good recovery of the maximal incisal opening and a reproducible occlusion in 5 of the 6 patients. Radiographic evaluation showed better control of the condyle position in both the vertical and anteroposterior directions than in the mediolateral direction. The degree of accuracy between the planned and achieved screw positions were judged as good to excellent in all cases. Within the limitations of this study and the small sample size, the proposed device design allowed for good transfer of the virtual surgical plan to the operating room.

  20. Early-onset facioscapulohumeral muscular dystrophy - significance of pelvic extensors in sagittal spinal imbalance.

    Science.gov (United States)

    Lee, Choon Sung; Kang, Suk Jung; Hwang, Chang Ju; Lee, Sung-Woo; Ahn, Young-Joon; Kim, Yung-Tae; Lee, Dong-Ho; Lee, Mi Young

    2009-11-01

    Although facioscapulohumeral muscular dystrophy (FSHD) is the third most common inherited myopathy, cases of infantile or early-childhood onset have rarely been reported. The purpose of this study was to describe a case of early-onset FSHD with lumbar hyperlordosis, which shows the significance of the dynamic component of sagittal spinal imbalance. An 11-year-old girl presented with progressive gait disturbance and lumbar hyperlordosis. The motor power of her pelvic extensor muscles was grade 3. Pelvic tilt and hip flexion were markedly increased as determined by gait analysis. The most important factor in the development of hyperlordosis is the weakness of the pelvic extensor muscles, and the results of gait analysis exquisitely explain the pathophysiology. The patient stands with her spine hyperextended to maintain upright posture by a compensatory mechanism of relatively strong back extensor muscles. Corrective surgery for lumbar hyperlordosis was not considered because it could have eliminated the compensatory lumbar hyperextension, thus making the spine of the patient stoop forward through her hip joint during walking by the weakness of her pelvic extensor muscles. This FSHD case is an impressive example of a patient showing the concept that weak pelvic extensor muscles cannot keep the spine upright and balanced.

  1. Rapid Hip Osteoarthritis Development in a Patient with Anterior Acetabular Cyst with Sagittal Alignment Change

    Directory of Open Access Journals (Sweden)

    Yasuhiro Homma

    2014-01-01

    Full Text Available Rapidly destructive coxarthrosis (RDC is rare and develops unusual clinical course. Recent studies suggest multiple possible mechanisms of the development of RDC. However the exact mechanism of RDC is still not clear. The difficulty of the study on RDC is attributed to its rareness and the fact that the data before the onset of RDC is normally unavailable. In this report, we presented the patient having the radiographic data before the onset who had rapid osteoarthritis (OA development after contralateral THA, which meets the current criteria of RDC. We thought that the increased posterior tilt of the pelvis after THA reinforced the stress concentration at pre-existed anterior acetabular cyst, thereby the destruction of the cyst was occurred. As a result the rapid OA was developed. We think that there is the case of rapid osteoarthritis developing due to alternating load concentration by posterior pelvic tilt on preexisting anterior acetabular cyst such as our patient among the cases diagnosed as RDC without any identifiable etiology. The recognition of sagittal alignment changes and anterior acetabular cyst may play important role in prediction and prevention of the rapid hip osteoarthritis development similar to RDC.

  2. Influence of the design in sagittal split ramus osteotomy on the mechanical behavior.

    Science.gov (United States)

    Pozzer, Leandro; Olate, Sergio; Cavalieri-Pereira, Lucas; de Moraes, Márcio; Albergaría-Barbosa, José Ricardo

    2014-01-01

    The aim of this study was to determine the influence of the design of the sagittal split ramus osteotomy (SSRO) on the mechanical resistance to vertical forces. An in vitro study was designed for 30 test specimens. Two osteotomy models were made on two polyurethane hemimandibles, where group I presented a SSRO with an angle at vestibular level between both molars and group II presented a linear SSRO towards the basilar border. In both groups a standard osteosynthesis was performed with a 2.0 system plate and four monocortical screws, establishing sub-groups according to the degree of mandibular advancement: group A without advancement, group B with an advancement of 3 mm, and group C with advancement of 7 mm. Hemimandibles were subjected to a vertical load in the Instron machine until reaching peak load with failure, recording the value of the load and displacement. The data were analyzed with a t-test to establish statistical significance, considering pdesign influences mechanical resistance and that the linear SSRO offers the best mechanical resistance.

  3. Complications of Bilateral Sagittal Split Osteotomy in Patients with Mandibular Prognathism

    Directory of Open Access Journals (Sweden)

    Majid Eshghpour

    2013-12-01

    Full Text Available Introduction: Bilateral sagittal split osteotomy (BSSO of mandible is vastly used in treatment of mandibular deficiencies and discrepancies. Since this method could affect esthetic as well as function, evaluating these effects from various aspects is crucial. This study assessed the effects of this technique on the function of masseter muscle, jaw movements, and sensory changes along with failures in screws used for fixation. Methods: 48 patients with mandibular prognathism participated. Electromyography (EMG of the masseter muscle; limits of jaw movements including maximum opening (MIO, protrusive (PM, lateral movements (LLE and LRE; presences of sensory changes and two point discrimination test; and number of removed screws were recorded at the baseline, 3 months, and 6 months after surgery. Results: EMG activity of masseter decreased significantly 3 months after the surgery. However, after 6 months the masseter activity revealed no statistically significant difference with baseline activity. There was a significant decrease in MIO and PM after 3 months. The 6 month measurement of MIO and PM was also lower than baseline. However, no difference was observed between LRE and LLE in both follow up sessions. Among 46 patients, 27 patients developed lip paresthesia 3 months after surgery. After 6 month, lip paresthesia remained in 11 patients. Among 276 screws used for fixation 3 screws removed due to exposure to oral cavity and 2 due to patient discomfort. Conclusion: As BSSO in patients with mandibular prognathism revealed temporary functional and sensory changes, it is a safe and appropriate method in orthognathic surgery.

  4. Changes in sagittal plane kinematics with treadmill familiarization to barefoot running.

    Science.gov (United States)

    Moore, Isabel S; Dixon, Sharon J

    2014-10-01

    Interest in barefoot running and research on barefoot running are growing. However a methodological issue surrounding investigations is how familiar the participants are with running barefoot. The aim of the study was to assess the amount of time required for habitually shod runners to become familiar with barefoot treadmill running. Twelve female recreational runners, who were experienced treadmill users, ran barefoot on a treadmill for three bouts, each bout consisting of 10 minutes at a self-selected speed with 5 minute rest periods. Sagittal plane kinematics of the hip, knee, ankle, and foot during stance were recorded during the first and last minute of each 10-minute bout. Strong reliability (ICC > .8) was shown in most variables after 20 minutes of running. In addition, there was a general trend for the smallest standard error of mean to occur during the same period. Furthermore, there were no significant differences in any of the biomechanical variables after 20 minutes of running. Together, this suggests that familiarization was achieved between 11 and 20 minutes of running barefoot on a treadmill. Familiarization was characterized by less plantar flexion and greater knee flexion at touchdown. These results indicate that adequate familiarization should be given in future studies before gait assessment of barefoot treadmill running.

  5. Hybrid fixation in the bilateral sagittal split osteotomy for lower jaw advancement

    Directory of Open Access Journals (Sweden)

    Felipe Ladeira Pereira

    2010-02-01

    Full Text Available Miniplate and screw fixation has been widely used in bilateral sagittal split osteotomy, but some issues remain unclear concerning its lack of rigidity when compared to Spiessl's bicortical technique. This paper demonstrates the hybrid fixation technique in a case report. A 34-year-old female patient underwent a double jaw surgery with counter-clockwise rotation of the mandible fixed using the hybrid fixation technique. The patient evolved well in the postoperative period and is still under follow up after 14 months, reporting satisfaction with the results and no significant deviation from the treatment plan up to now. No damage to tooth roots was done, maxillomandibular range of motion was within normality and regression of the inferior alveolar nerve paresthesia was observed bilaterally. The hybrid mandibular fixation is clearly visible in the panoramic and cephalometric control radiographs. It seems that the hybrid fixation can sum the advantages of both monocortical and bicortical techniques in lower jaw advancement, increasing fixation stability without significant damage to the mandibular articulation and the inferior alveolar nerve. A statistical investigation seems necessary to prove its efficacy.

  6. A work-loop method for characterizing leg function during sagittal plane movements.

    Science.gov (United States)

    Maykranz, Daniel; Grimmer, Sten; Seyfarth, Andre

    2013-10-01

    The work-loop method is frequently used to determine the mechanical work performed by a system, for instance, when analyzing muscles or describing the work balance at the joint level. While for these examples usually only one-dimensional movements are investigated, for two- or three-dimensional movements, such as leg function during walking and running, the work-loop has to be adapted. In this paper, we present an analytical derivation that extends the work-loop method to two-dimensional sagittal plane movements. Three effects contribute to the mechanical work of the leg: (1) forces directed along the leg axis, (2) forces acting perpendicular to the leg axis, and (3) a shift of the center of pressure (COP) during stance. These three contributors to the mechanical work performed can be interpreted as three general tasks of the leg. To demonstrate the new work-loop method, we analyzed experimental data on hopping, running and walking. The results indicate that the proposed new generalized work-loop concept is suitable for describing the overall mechanical work performed on the COM during stance with energy consistent net work balances. Depending on the type of gait, specific contributions of each work term were found that characterize leg function during locomotion.

  7. A Bayesian Approach to Period Searching in Solar Coronal Loops

    Science.gov (United States)

    Scherrer, Bryan; McKenzie, David

    2017-03-01

    We have applied a Bayesian generalized Lomb–Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Program #129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.

  8. Competition between shock and turbulent heating in coronal loop system

    CERN Document Server

    Matsumoto, Takuma

    2016-01-01

    2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfv\\'{e}n waves excited in the photosphere is the target of the present study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfv\\'{e}n waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 % of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The i...

  9. Investigation of Coronal Large Scale Structures Utilizing Spartan 201 Data

    Science.gov (United States)

    Guhathakurta, Madhulika

    1998-01-01

    Two telescopes aboard Spartan 201, a small satellite has been launched from the Space Shuttles, on April 8th, 1993, September 8th, 1994, September 7th, 1995 and November 20th, 1997. The main objective of the mission was to answer some of the most fundamental unanswered questions of solar physics-What accelerates the solar wind and what heats the corona? The two telescopes are 1) Ultraviolet Coronal Spectrometer (UVCS) provided by the Smithsonian Astrophysical Observatory which uses ultraviolet emissions from neutral hydrogen and ions in the corona to determine velocities of the coronal plasma within the solar wind source region, and the temperature and density distributions of protons and 2) White Light Coronagraph (WLC) provided by NASA's Goddard Space Flight Center which measures visible light to determine the density distribution of coronal electrons within the same region. The PI has had the primary responsibility in the development and application of computer codes necessary for scientific data analysis activities, end instrument calibration for the white-light coronagraph for the entire Spartan mission. The PI was responsible for the science output from the WLC instrument. PI has also been involved in the investigation of coronal density distributions in large-scale structures by use of numerical models which are (mathematically) sufficient to reproduce the details of the observed brightness and polarized brightness distributions found in SPARTAN 201 data.

  10. Coronal heating by resonant absorption: The effects of chromospheric coupling

    NARCIS (Netherlands)

    Belien, A. J. C.; Martens, P. C. H.; Keppens, R.

    1999-01-01

    We present the first 2.5 dimensional numerical model calculations of the nonlinear wave dynamics and heating by resonant absorption in coronal loops with thermal structuring of the transition region and higher chromosphere. The numerical calculations were done with the Versatile Advection Code. The

  11. Closed-Field Coronal Heating Driven by Wave Turbulence

    CERN Document Server

    Downs, Cooper; Mikić, Zoran; Linker, Jon A; Velli, Marco

    2016-01-01

    To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence-driven (WTD) phenomenology for the heating of closed coronal loops. Our implementation is designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic evolution in 1D for an idealized loop. The relevance to a range of solar conditions is also established by computing solutions for over one hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditiona...

  12. Data-driven coronal evolutionary model of active region 11944.

    Science.gov (United States)

    Kazachenko, M.

    2014-12-01

    Recent availability of systematic measurements of vector magnetic fields and Doppler velocities has allowed us to utilize a data-driven approach for modeling observed active regions (AR), a crucial step for understanding the nature of solar flare initiation. We use a sequence of vector magnetograms and Dopplergrams from the Helioseismic and Magnetic Imager (HMI) aboard the SDO to drive magnetofrictional (MF) model of the coronal magnetic field in the the vicinity of AR 11944, where an X1.2 flare on January 7 2014 occurred. To drive the coronal field we impose a time-dependent boundary condition based on temporal sequences of magnetic and electric fields at the bottom of the computational domain, i.e. the photosphere. To derive the electric fields we use a recently improved poloidal-toroidal decomposition (PTD), which we call the ``PTD-Doppler-FLCT-Ideal'' or PDFI technique. We investigate the results of the simulated coronal evolution, compare those with EUV observations from Atmospheric Imaging Assembly (AIA) and discuss what we could learn from them. This work is a a collaborative effort from the UC Berkeley Space Sciences Laboratory (SSL), Stanford University, and Lockheed-Martin and is a part of Coronal Global Evolutionary (CGEM) Model, funded jointly by NASA and NSF.

  13. Quantifying the Significance of Substructure in Coronal Loops

    Science.gov (United States)

    McKeough, K. B. D.; Kashyap, V.; McKillop, S.

    2014-12-01

    A method to infer the presence of small-scale substructure in SDO/AIA (Atmospheric Imaging Assembly on the Solar Dynamics Observatory) images of coronal loops is developed. We can classify visible loop structure based on this propensity to show substructure which puts constraints on contemporary solutions to the coronal heating problem. The method uses the Bayesian algorithm Low-count Image Reconstruction and Analysis (LIRA) to infer the multi-scale component of the loops which describes deviations from a smooth model. The increase in contrast of features in this multi-scale component is determined using a statistic that estimates the sharpness across the image. Regions with significant substructure are determined using p-value upper bounds. We are able to locate substructure visible in Hi-C (High-Resolution Coronal Imager) data that are not salient features in the corresponding AIA image. Looking at coronal loops at different regions of the Sun (e.g., low-lying structure and loops in the upper corona) we are able to map where detectable substructure exists and thus the influence of the nanoflare heating process. We acknowledge support from AIA under contract SP02H1701R from Lockheed-Martin to SAO.

  14. Arthroscopic Treatment of Medial Femoral Condylar Coronal Fractures and Nonunions

    Science.gov (United States)

    Ercin, Ersin; Bilgili, M. Gokhan; Basaran, S. Hakan; Baca, Emre; Kural, Cemal; Avkan, M. Cevdet

    2013-01-01

    Nonunion of medial femoral condylar coronal fractures are uncommon. In neglected Hoffa fractures despite nonunion, there is a risk of missing accompanying ligamentous and intra-articular injuries. Neither preoperative clinical examination nor magnetic resonance imaging showed these injuries before arthroscopy. Arthroscopy before internal fixation gives additional information and changes the surgical protocol for these fractures and nonunions. PMID:24400191

  15. Competition between shock and turbulent heating in coronal loop system

    Science.gov (United States)

    Matsumoto, Takuma

    2016-11-01

    2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfvén waves excited in the photosphere is the target of this study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfvén waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 per cent of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The importance of compressibility shown in this study would significantly impact on the prospects of successful MHD turbulence theory in the solar chromosphere.

  16. The Relationship of Coronal Mass Ejections to Streamers

    CERN Document Server

    Subramanian, P; Rich, N B; Howard, R A; Subramanian, Prasad

    1999-01-01

    We have examined images from the Large Angle Spectroscopic Coronagraph (LASCO) to study the relationship of Coronal Mass Ejections (CMEs) to coronal streamers. We wish to test the suggestion (Low 1996) that CMEs arise from flux ropes embedded in a streamer erupting, thus disrupting the streamer. The data span a period of two years near sunspot minimum through a period of increased activity as sunspot numbers increased. We have used LASCO data from the C2 coronagraph which records Thomson scattered white light from coronal electrons at heights between 1.5 and 6R_sun. Maps of the coronal streamers have been constructed from LASCO C2 observations at a height of 2.5R_sun at the east and west limbs. We have superposed the corresponding positions of CMEs observed with the C2 coronagraph onto the synoptic maps. We identified the different kinds of signatures CMEs leave on the streamer structure at this height (2.5R_sun). We find four types of CMEs with respect to their effect on streamers: 1. CMEs that disrupt the s...

  17. Investigations on Experimental Impellers for Axial Blowers

    Science.gov (United States)

    Encke, W.

    1947-01-01

    A selection of measurements obtained on experimental impellers for axial blowers will be reported. In addition to characteristic curves plotted for low and for high peripheral velocities, proportions and blade sections for six different blower models and remarks on the design of blowers will be presented.

  18. Excitation modes in non-axial nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.; Ginnochio, J.N.

    1990-01-01

    Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both {gamma}-unstable and {gamma}-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs.

  19. Ankylosing Spondylitis versus Nonradiographic Axial Spondyloarthritis

    DEFF Research Database (Denmark)

    Glintborg, Bente; Sørensen, Inge J; Østergaard, Mikkel

    2017-01-01

    OBJECTIVE: To compare baseline disease activity and treatment effectiveness in biologic-naive patients with nonradiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) who initiate tumor necrosis factor inhibitor (TNFi) treatment and to study the role of potential confounders...

  20. Wave propagation in axially moving periodic strings

    DEFF Research Database (Denmark)

    Sorokin, Vladislav S.; Thomsen, Jon Juel

    2017-01-01

    The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drive...

  1. CHARACTERISTICS OF BODY POSTURE IN THE SAGITTAL PLANE AND FITNESS OF FIRST-FORM PUPILS FROM RURAL AREAS

    OpenAIRE

    Żukowska Hanna; Szark-Eckardt Mirosława; Muszkieta Radosław; Iermakova T.S.

    2014-01-01

    Purpose: to find correlations between characteristics of body posture in the sagittal plane and fitness and endurance of first-form children from rural areas. Material: an analysis of more than 30 sources of scientific and educational literature. Results: the study involved 209 children, including 102 girls and 107 boys. They were children who lived in the country since they were born. To assess particular characteristics of body posture, the children were studied by means of the measuring eq...

  2. Early Outcomes of Minimally Invasive Anterior Longitudinal Ligament Release for Correction of Sagittal Imbalance in Patients with Adult Spinal Deformity

    Directory of Open Access Journals (Sweden)

    Armen R. Deukmedjian

    2012-01-01

    Full Text Available The object of this study was to evaluate a novel surgical technique in the treatment of adult degenerative scoliosis and present our early experience with the minimally invasive lateral approach for anterior longitudinal ligament release to provide lumbar lordosis and examine its impact on sagittal balance. Methods. All patients with adult spinal deformity (ASD treated with the minimally invasive lateral retroperitoneal transpsoas interbody fusion (MIS LIF for release of the anterior longitudinal ligament were examined. Patient demographics, clinical data, spinopelvic parameters, and outcome measures were recorded. Results. Seven patients underwent release of the anterior longitudinal ligament (ALR to improve sagittal imbalance. All cases were split into anterior and posterior stages, with mean estimated blood loss of 125 cc and 530 cc, respectively. Average hospital stay was 8.3 days, and mean follow-up time was 9.1 months. Comparing pre- and postoperative 36′′ standing X-rays, the authors discovered a mean increase in global lumbar lordosis of 24 degrees, increase in segmental lumbar lordosis of 17 degrees per level of ALL released, decrease in pelvic tilt of 7 degrees, and decrease in sagittal vertical axis of 4.9 cm. At the last followup, there was a mean improvement in VAS and ODI scores of 26.2% and 18.3%. Conclusions. In the authors’ early experience, release of the anterior longitudinal ligament using the minimally invasive lateral retroperitoneal transpsoas approach may be a feasible alternative in correcting sagittal deformity.

  3. Effect of Long Term Oral Warfarin Sodium Treatment on Bone Mineral Density Scores and Spinal Sagittal Alignment

    Directory of Open Access Journals (Sweden)

    Kamil Eyvazov

    2016-04-01

    Full Text Available Objective: The aim of this study was to investigate the effect of long term oral warfarin sodium treatment on bone mineral density (BMD and spinal sagittal alignment. Materials and Methods: Sixty four participants were enrolled for this retrospective study. Participants were divided into two groups-participants who had taken warfarin sodium for at least two years (n=33 and participants who had never taken warfarin sodium (n=31. All of the individuals were evaluated at the same center. Dual X-ray absorptiometry (DXA was used for measuring BMD. Whole spine x-rays were obtained for sagittal assessment and the following parameters were measured: Cervical lordosis, thoracic kyphosis, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope and sagittal vertical axis (SVA. Results: The mean BMD value was significantly higher in participants who had not taken warfarin sodium compared to participants who had taken warfarin sodium. The differences between the average values were 0.1552 g/cm2 in BMD; 2.1 in T scores; 1.4 in Z scores. On the radiological evaluation of the spine, cervical lordosis was 7.1 degrees lower, lumbar lordosis was 4.7 degrees lower and thoracic kyphosis was 5.3 degrees higher in the patients using drug. C7 plumb line was interchanged forward in the patients using drug. Conclusions: This study shows that warfarin sodium use worsens bone quality in the lumbar region and does not affect bone quality in the femoral region. Furthermore, warfarin sodium use also reduces physiological lordosis and enhances thoracic kyphosis. Consequences of these changes are the likely cause of sagittal spinal anterior imbalance. Long-term oral warfarin sodium use affect bone mineral density and spinal alignment. Our conclusion about giving clear message and show exactly mechanism we need prospective randomized multicentre studies in future. We strongly believe this study will be pioneer for future researches.

  4. Cephalometric Investigation of First Cervical Vertebrae Morphology and Hyoid Position in Young Adults with Different Sagittal Skeletal Patterns

    Directory of Open Access Journals (Sweden)

    Seher Gündüz Arslan

    2014-01-01

    Full Text Available The aim of this retrospective study was to examine hyoid bone position and C1 (atlas morphology in males and females and analyze these parameters with respect to different sagittal skeletal patterns via cephalometry, with the goal of identifying cephalometric norms. Lateral cephalometric radiographs from 120 individuals (average age: 21.1 ± 2.9 years were classified according to their ANB angle (Class I, II, or III and used to assess 14 parameters. Class I and II patients showed significant differences in Hy-NSL, Hy-PD, Hy-CVT, Lum, and a-p measurements. These parameters were consistently larger in males than in females. Intergroup comparisons among males showed significant differences in the SNA, ANB, Hy-CVT, X, and Z measurements. The hyoid was positioned more inferiorly and anteriorly and was more prominent in males than in females in all groups. Among participants exhibiting a Class I skeletal pattern, C1 was also larger in the anterior-posterior direction in males than in females. In the sagittal plane, the hyoid was positioned similarly in males with either Class I or III skeletal patterns but was positioned posteriorly in males with a Class II skeletal pattern. In addition, the vertical position of C1 varied with sagittal skeletal pattern in males.

  5. The femoro-sacral posterior angle: an anatomical sagittal pelvic parameter usable with dome-shaped sacrum.

    Science.gov (United States)

    Legaye, Jean

    2007-02-01

    The sagittal pelvic morphology modulates the individual alignment of the spine. Anatomical angular parameters were described as follows: the "Pelvic Incidence" (PI) and the Jackson's angle "Pelvic Lordosis" (PR-S1). Significant chains of relationships were expressed connecting these angles with pelvic and spinal positional parameters. This allows an individual assessment of the harmony of the sagittal spinal balance. But in case of spondylolysis with high-grade listhesis, the upper plate of the sacrum shows a dome-shaped deformity. The previous anatomical parameters are therefore imprecise. Indeed, the anterior part of the sacrum being inaccurate, an exact assessment of these angles becomes impossible. Therefore, we propose a new angular parameter named "Femoro-Sacral Posterior Angle" (FSPA): the angle between the posterior wall of the first sacral vertebra, always well definite, and the line connecting the posterior part of the sacral plate to the femoral axis. The validation of this parameter was performed and compared with the classical published parameters. It showed good inter-observer reliability, even with dome-shaped sacral plate. In spite of lower correlation with the positional parameters than those observed with PI or PR-S1, the FSPA appeared to be reliable and precise for an exact evaluation of the sagittal spino-pelvic balance is case of spondylo-listhesis with dome-shaped sacral endplate.

  6. Relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability.

    Science.gov (United States)

    Lau, Kwok Tung; Cheung, Ka Yuen; Chan, Kwok Bun; Chan, Man Him; Lo, King Yuen; Chiu, Thomas Tai Wing

    2010-10-01

    This was a cross-sectional correlation study to explore the relationships between sagittal postures of thoracic and cervical spine, presence of neck pain, neck pain severity and disability. Moreover, the reliability of the photographic measurement of the sagittal posture of thoracic and cervical spine was investigated. Forty-five subjects without neck pain and forty-seven subjects with neck pain were recruited. Using a photographic method, the sagittal thoracic and cervical postures were measured by the upper thoracic and the craniovertebral (CV) angles respectively. The Numeric Pain Rating Scale (NPRS) and Chinese version Northwick Park Neck Pain Questionnaire (NPQ) were used to assess neck pain severity and disability. The upper thoracic angle was positively correlated (r(s) = 0.63, p angle was negatively correlated (r(s) = -0.56, p upper thoracic angle was negatively correlated with the CV angles (r(s) = -0.62, p angle, the upper thoracic angle was moderately correlated with the neck pain severity (r(s) = 0.43, p = 0.01) and disability (r(s) = 0.44, p = 0.02). The upper thoracic angle (OR = 1.37, p angle (OR = 0.86, p = 0.04).

  7. Magnetic Field in the Gravitationally Stratified Coronal Loops

    Indian Academy of Sciences (India)

    B. N. Dwivedi; A. K. Srivastava

    2015-03-01

    We study the effect of gravitational stratification on the estimation of magnetic fields in the coronal loops. By using the method of MHD seismology of kink waves for the estimation of magnetic field of coronal loops, we derive a new formula for the magnetic field considering the effect of gravitational stratification. The fast-kink wave is a potential diagnostic tool for the estimation of magnetic field in fluxtubes. We consider the eleven kink oscillation cases observed by TRACE between July 1998 and June 2001. We calculate magnetic field in the stratified loops (str) and compare them with the previously calculated absolute magnetic field (abs). The gravitational stratification efficiently affects the magnetic field estimation in the coronal loops as it affects also the properties of kink waves. We find ≈22% increment in the magnetic field for the smallest ( = 72 Mm) while ≈42% increment in the absolute magnetic field for the longest ( = 406 Mm) coronal loops. The magnetic fields str and abs also increase with the number density, if the loop length does not vary much. The increment in the magnetic field due to gravitational stratification is small at the lower number densities, however, it is large at the higher number densities. We find that damping time of kink waves due to phase-mixing is less in the case of gravitationally stratified loops compared to nonstratified ones. This indicates the more rapid damping of kink waves in the stratified loops. In conclusion, we find that the gravitational stratification efficiently affects the estimation of magnetic field and damping time estimation especially in the longer coronal loops.

  8. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    Science.gov (United States)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  9. Might axial myofascial properties and biomechanical mechanisms be relevant to ankylosing spondylitis and axial spondyloarthritis?

    OpenAIRE

    Masi, Alfonse T.

    2014-01-01

    Ankylosing spondylitis and axial spondyloarthropathy have characteristic age- and sex-specific onset patterns, typical entheseal lesions, and marked heritability, but the integrative mechanisms causing the pathophysiological and structural alterations remain largely undefined. Myofascial tissues are integrated in the body into webs and networks which permit transmission of passive and active tensional forces that provide stabilizing support and help to control movements. Axial myofascial hype...

  10. On the nature of transverse coronal waves revealed by wavefront dislocations

    CERN Document Server

    Ariste, A López; Arregui, I; Khomenko, E; Collados, M

    2015-01-01

    Coronal waves are an important aspect of the dynamics of the plasma in the corona. Wavefront dislocations are topological features of most waves in nature and also of magnetohydrodynamic waves. Are there dislocations in coronal waves? The finding and explanation of dislocations may shed light on the nature and characteristics of the propagating waves, their interaction in the corona and in general on the plasma dynamics. We positively identify dislocations in coronal waves observed by the Coronal Multi-channel Polarimeter (CoMP) as singularities in the Doppler shifts of emission coronal lines. We study the possible singularities that can be expected in coronal waves and try to reproduce the observed dislocations in terms of localization and frequency of appearance. The observed dislocations can only be explained by the interference of a kink and a sausage wave modes propagating with different frequencies along the coronal magnetic field. In the plane transverse to the propagation, the cross-section of the osc...

  11. Intra- and inter-observer reliability of determining radiographic sagittal parameters of the spine and pelvis using a manual and a computer-assisted methods.

    Science.gov (United States)

    Dimar, John R; Carreon, Leah Y; Labelle, Hubert; Djurasovic, Mladen; Weidenbaum, Mark; Brown, Courtney; Roussouly, Pierre

    2008-10-01

    Sagittal imbalance is a significant factor in determining clinical treatment outcomes in patients with deformity. Measurement of sagittal alignment using the traditional Cobb technique is frequently hampered by difficulty in visualizing landmarks. This report compares traditional manual measurement techniques to a computer-assisted sagittal plane measurement program which uses a radius arc methodology. The intra and inter-observer reliability of the computer program has been shown to be 0.92-0.99. Twenty-nine lateral 90 cm radiographs were measured by a computer program for an array of sagittal plane measurements. Ten experienced orthopedic spine surgeons manually measured the same parameters twice, at least 48 h apart, using a digital caliper and a standardized radiographic manual. Intraclass correlations were used to determine intra- and interobserver reliability between different manual measures and between manual measures and computer assisted-measures. The inter-observer reliability between manual measures was poor, ranging from -0.02 to 0.64 for the different sagittal measures. The intra-observer reliability in manual measures was better ranging from 0.40 to 0.93. Comparing manual to computer-assisted measures, the ICC ranged from 0.07 to 0.75. Surgeons agreed more often with each other than with the machine when measuring the lumbar curve, the thoracic curve, and the spino-sacral angle. The reliability of the computer program is significantly higher for all measures except for lumbar lordosis. A computer-assisted program produces a reliable measurement of the sagittal profile of the spine by eliminating the need for distinctly visible endplates. The use of a radial arc methodology allows for infinite data points to be used along the spine to determine sagittal measurements. The integration of this technique with digital radiography's ability to adjust image contrast and brightness will enable the superior identification of key anatomical parameters normally

  12. Does the sagittal alignment of the cervical spine have an impact on disk degeneration? Minimum 10-year follow-up of asymptomatic volunteers

    OpenAIRE

    2009-01-01

    There have been few studies that investigated and clarified the relationships between progression of degenerative changes and sagittal alignment of the cervical spine. The objective of the study was to longitudinally evaluate the relationships among progression of degenerative changes of the cervical spine with age, the development of clinical symptoms and sagittal alignment of the cervical spine in healthy subjects. Out of 497 symptom-free volunteers who underwent MRI and plain radiography o...

  13. Spinal curves and health: a systematic critical review of the epidemiological literature dealing with associations between sagittal spinal curves and health

    DEFF Research Database (Denmark)

    Christensen, Sanne Toftgaard; Hartvigsen, Jan

    2008-01-01

    The purposes of this study were to (1) determine whether sagittal spinal curves are associated with health in epidemiological studies, (2) estimate the strength of such associations, and (3) consider whether these relations are likely to be causal.......The purposes of this study were to (1) determine whether sagittal spinal curves are associated with health in epidemiological studies, (2) estimate the strength of such associations, and (3) consider whether these relations are likely to be causal....

  14. The impact of sagittal balance on clinical results after posterior interbody fusion for patients with degenerative spondylolisthesis: A Pilot study

    Directory of Open Access Journals (Sweden)

    Chung Sung-Soo

    2011-04-01

    Full Text Available Abstract Background Comparatively little is known about the relation between the sagittal vertical axis and clinical outcome in cases of degenerative lumbar spondylolisthesis. The objective of this study was to determine whether lumbar sagittal balance affects clinical outcomes after posterior interbody fusion. This series suggests that consideration of sagittal balance during posterior interbody fusion for degenerative spondylolisthesis can yield high levels of patient satisfaction and restore spinal balance Methods A retrospective study of clinical outcomes and a radiological review was performed on 18 patients with one or two level degenerative spondylolisthesis. Patients were divided into two groups: the patients without improvement in pelvic tilt, postoperatively (Group A; n = 10 and the patients with improvement in pelvic tilt postoperatively (Group B; n = 8. Pre- and postoperative clinical outcome surveys were administered to determine Visual Analogue Pain Scores (VAS and Oswestry disability index (ODI. In addition, we evaluated full spine radiographic films for pelvic tilt (PT, sacral slope (SS, pelvic incidence (PI, thoracic kyphosis (TK, lumbar lordosis (LL, sacrofemoral distance (SFD, and sacro C7 plumb line distance (SC7D Results All 18 patients underwent surgery principally for the relief of radicular leg pain and back pain. In groups A and B, mean preoperative VAS were 6.85 and 6.81, respectively, and these improved to 3.20 and 1.63 at last follow-up. Mean preoperative ODI were 43.2 and 50.4, respectively, and these improved to 23.6 and 18.9 at last follow-up. In spinopelvic parameters, no significant difference was found between preoperative and follow up variables except PT in Group A. However, significant difference was found between the preoperative and follows up values of PT, SS, TK, LL, and SFD/SC7D in Group B. Between parameters of group A and B, there is borderline significance on preoperative PT, preoperative LL and last

  15. Three-dimensional study of oropharyngeal airway structural differences between sagittal skeletal Class Ⅰ and Ⅱ patients%骨型Ⅰ类和Ⅱ类患者口咽气道三维结构差异研究

    Institute of Scientific and Technical Information of China (English)

    秦璐; 邹冰爽; 余哲; 赵颖

    2015-01-01

    目的 利用三维影像扫描和重建技术、三维头影测量技术,比较骨型Ⅰ类和Ⅱ类正畸患者口咽气道的三维结构差异.方法 根据研究对象的骨面型分为骨型Ⅰ类组和骨型Ⅱ类组,年龄、性别严格匹配、均角研究对象共22对.将所有研究对象正畸初诊时拍摄的全头颅CBCT影像导入Dolphin Imaging 3D软件进行三维重建并分别测量其口咽气道、腭咽气道、舌咽气道的气道容积、气道长度、最小横截面积、最小横截面矢状径、横径及其比例关系,对两组间的气道指标进行统计学分析比较.结果 骨型Ⅱ类患者的舌咽气道最小横截面积[(144.27±68.30) mm2]及口咽气道最小横截面矢状径[(8.28±2.58) mm]较骨型Ⅰ类患者[(193.93±71.54) mm2,(9.76±2.22) mm]小(P≤0.05).结论 骨型Ⅰ类和Ⅱ类患者口咽气道三维结构具有一定差异,矢状骨型对口咽气道结构具有一定影响.%Objective To study and compare the 3D structural differences of oropharyngeal airway between sagittal skeletal class Ⅰ and Ⅱ patients by 3-dimensional imaging,reconstruction and measurement.Methods 22 paired patients who were of vertical skeletal class Ⅰ and strictly matched according to age,gender,were divided into sagittal skeletal class Ⅰ and Ⅱ groups.Patients' CBCT image data at first visit were reconstructed by Dolphin Imaging 3D software.Then airway volume,minimum axial area and airway length of oropharyngeal,velopharyngeal and glossopharyngeal airway,anteroposterior and lateral length of the minimum axial area were measured and compared.Results The minimum axial area of glossopharyngeal airway in skeletal class Ⅱ patients [(144.27 ± 68.30) mm2] and anteroposterior of length minimum axial area [(8.28±2.58) mm] were significantly smaller than that of skeletal class Ⅰ patients [(193.93±71.54) mm2,(9.76±2.22) mm](P≤0.05).Conclusions Skeletal class Ⅰ and Ⅱ patients present different oropharyngeal airway

  16. Selective Distribution of Retinal Input to Mouse SCN Revealed in Analysis of Sagittal Sections.

    Science.gov (United States)

    Lokshin, Maria; LeSauter, Joseph; Silver, Rae

    2015-06-01

    The suprachiasmatic nucleus (SCN) is the locus of the master circadian clock, setting the daily rhythms in physiology and behavior and synchronizing these responses to the local environment. The most important of these phase-setting cues derive from the light-dark cycle and reach the SCN directly via the retinohypothalamic tract (RHT). The SCN contains anatomically and functionally heterogeneous populations of cells. Understanding how these neurons access information about the photic environment so as to set the phase of daily oscillation requires knowledge of SCN innervation by the RHT. While retinal innervation of the SCN has long been a topic of interest, the information is incomplete. In some instances, studies have focused on the caudal aspect of the nucleus, which contains the core region. In other instances, subregions of the nucleus have been delineated based on projections of where specific peptidergic cell types lie, rather than based on double or triple immunochemical staining of distinct populations of cells. Here, we examine the full extent of the mouse SCN using cholera toxin β (CTβ) as a tracer to analyze RHT innervation in triple-labeled sagittal sections. Using specific peptidergic markers to identify clusters of SCN cells, we find 3 distinct patterns. First is an area of dense RHT innervation to the core region, delineated by gastrin-releasing peptide (GRP) and vasoactive intestinal peptide (VIP) immunoreactive cells. Second is an area of moderate RHT fiber clusters, bearing arginine-vasopressin (AVP)-positive cells that lie close to the core. Finally, the outermost, shell, and rostral AVP-containing regions of the SCN have few to no detectable retinal fibers. These results point to a diversity of inputs to individual SCN cell populations and suggest variation in the responses that underlie photic phase resetting.

  17. 3D analysis of condylar remodelling and skeletal relapse following bilateral sagittal split advancement osteotomies.

    Science.gov (United States)

    Xi, Tong; Schreurs, Ruud; van Loon, Bram; de Koning, Martien; Bergé, Stefaan; Hoppenreijs, Theo; Maal, Thomas

    2015-05-01

    A major concern in mandibular advancement surgery using bilateral sagittal split osteotomies (BSSO) is potential postoperative relapse. Although the role of postoperative changes in condylar morphology on skeletal relapse was reported in previous studies, no study so far has objectified the precise changes of the condylar volume. The aim of the present study was to quantify the postoperative volume changes of condyles and its role on skeletal stability following BSSO mandibular advancement surgery. A total of 56 patients with mandibular hypoplasia who underwent BSSO advancement surgery were prospectively enrolled into the study. A cone beam computed tomography (CBCT) scan was acquired preoperatively, at 1 week postoperatively and at 1 year postoperatively. After the segmentation of the facial skeleton and condyles, three-dimensional cephalometry and condylar volume analysis were performed. The mean mandibular advancement was 4.6 mm, and the mean postoperative relapse was 0.71 mm. Of 112 condyles, 55% showed a postoperative decrease in condylar volume, with a mean reduction of 105 mm(3) (6.1% of the original condylar volume). The magnitude of condylar remodelling (CR) was significantly correlated with skeletal relapse (p = 0.003). Patients with a CR greater than 17% of the original condylar volume exhibited relapse as seen in progressive condylar resorption. Female patients with a high mandibular angle who exhibited postoperative CR were particularly at risk for postoperative relapse. Gender, preoperative condylar volume, and downward displacement of pogonion at surgery were prognostic factors for CR (r(2) = 21%). It could be concluded that the condylar volume can be applied as a useful 3D radiographic parameter for the diagnosis and follow-up of postoperative skeletal relapse and progressive condylar resorption.

  18. Muscle contributions to whole-body sagittal plane angular momentum during walking.

    Science.gov (United States)

    Neptune, R R; McGowan, C P

    2011-01-01

    Walking is a complex dynamic task that requires the regulation of whole-body angular momentum to maintain dynamic balance while performing walking subtasks such as propelling the body forward and accelerating the leg into swing. In human walking, the primary mechanism to regulate angular momentum is muscle force generation. Muscles accelerate body segments and generate ground reaction forces that alter angular momentum about the body's center-of-mass to restore and maintain dynamic stability. In addition, gravity contributes to whole-body angular momentum through its contribution to the ground reaction forces. The purpose of this study was to generate a muscle-actuated forward dynamics simulation of normal walking to quantify how individual muscles and gravity contribute to whole-body angular momentum in the sagittal plane. In early stance, the uniarticular hip and knee extensors (GMAX and VAS), biarticular hamstrings (HAM) and ankle dorsiflexors (TA) generated backward angular momentum while the ankle plantar flexors (SOL and GAS) generated forward momentum. In late stance, SOL and GAS were the primary contributors and generated angular momentum in opposite directions. SOL generated primarily forward angular momentum while GAS generated backward angular momentum. The difference between muscles was due to their relative contributions to the horizontal and vertical ground reaction forces. Gravity contributed to the body's angular momentum in early stance and to a lesser extent in late stance, which was counteracted primarily by the plantar flexors. These results may provide insight into balance and movement disorders and provide a basis for developing locomotor therapies that target specific muscle groups.

  19. Distal Junctional Disease after Occipitothoracic Fusion for Rheumatoid Cervical Disorders: Correlation with Cervical Spine Sagittal Alignment.

    Science.gov (United States)

    Tanouchi, Tetsu; Shimizu, Takachika; Fueki, Keisuke; Ino, Masatake; Toda, Naofumi; Manabe, Nodoka; Itoh, Kanako

    2015-10-01

    Study Design Retrospective radiographic study. Objective We have performed occipitothoracic (OT) fusion for severe rheumatoid cervical disorders since 1991. In our previous study, we reported that the distal junctional disease occurred in patients with fusion of O-T4 or longer due to increased mechanical stress. The present study further evaluated the association between the distal junctional disease and the cervical spine sagittal alignment. Methods Among 60 consecutive OT fusion cases between 1991 and 2010, 24 patients who underwent O-T5 fusion were enrolled in this study. The patients were grouped based on whether they developed postoperative distal junctional disease (group F) or not (group N). We measured pre- and postoperative O-C2, C2-C7, and O-C7 angles and evaluated the association between these values and the occurrence of distal junctional disease. Results Seven (29%) of 24 patients developed adjacent-level vertebral fractures as distal junctional disease. In group F, the mean pre- and postoperative O-C2, C2-C7, and O-C7 angles were 12.1 and 16.8, 7.2 and 11.2, and 19.4 and 27.9 degrees, respectively. In group N, the mean pre- and postoperative O-C2, C2-C7, and O-C7 angles were 15.9 and 15.0, 4.9 and 5.8, and 21.0 and 20.9 degrees, respectively. There were no significant differences between the two groups. The difference in the O-C7 angle (postoperative angle - preoperative angle) in group F was significantly larger than that in group N (p = 0.04). Conclusion Excessive correction of the O-C7 angle (hyperlordotic alignment) is likely to cause postoperative distal junctional disease following the OT fusion.

  20. Treatment of chronic low back pain in patients with spinal deformities using a sagittal re-alignment brace

    Directory of Open Access Journals (Sweden)

    Weiss Hans-Rudolf

    2009-03-01

    Full Text Available Abstract Background For adult scoliosis patients with chronic low back pain bracing is initially indicated before spinal surgery is considered. Until recently there has been a lack of research into the effect upon pain reductions in the mid and long-term. Promising results have been documented in short-term studies for the application of a sagittal re-alignment brace in patients with spinal deformities and along with pain; however mid-term and long-term results are not yet available. The purpose of this study is to investigate the mid-term effects of this brace with respect to pain control. Materials and methods 67 patients (58 females and 9 males with chronic low back pain (> 24 months and the diagnosis of scoliosis or hyperkyphosis were treated with a sagittal re-alignment brace (physio-logic brace™ between January 2006 and July 2007. The indication for this kind of brace treatment was derived from a positive sagittal re-alignment test (SRT and the exclusion of successful conservative treatment during the last 24 months. The aim of this type of conservative intervention was to avoid surgery for chronic low back pain. Results The average pain intensity was measured on the Roland and Morris VRS (5 steps before treatment. This was 3.3 (t1, at the time of brace adjustment it was 2.7 (t2 and after at an average observation time of 18 months it was 2.0 (t3. The differences were highly significant in the Wilcoxon test. Discussion Short-term measurements showed that a significant pain reduction is possible in chronic postural low back pain using a sagittal re-alignment brace inducing lumbar re-lordosation. In a preliminary report at adjustment (t2, highly significant improvements of pain intensity have also been demonstrated. At 6 months of treatment however, no improvement was measured. The improvement of the mid-term effects (18 months found in this study compared to the preliminary report may be due to the changed approach to compliance: whilst

  1. Standing sausage modes in coronal loops with plasma flow

    Science.gov (United States)

    Li, Bo; Chen, Shao-Xia; Xia, Li-Dong; Yu, Hui

    2014-08-01

    Context. Magnetohydrodynamic waves are important for diagnosing the physical parameters of coronal plasmas. Field-aligned flows appear frequently in coronal loops. Aims: We examine the effects of transverse density and plasma flow structuring on standing sausage modes trapped in coronal loops, and examine their observational implications in the context of coronal seismology. Methods: We model coronal loops as straight cold cylinders with plasma flow embedded in a static corona. An eigen-value problem governing propagating sausage waves is formulated and its solutions are employed to construct standing modes. Two transverse profiles are distinguished, and are called profiles E and N. A parameter study is performed on the dependence of the maximum period Pmax and cutoff length-to-radius ratio (L/a)cutoff in the trapped regime on the density parameters (ρ0/ρ∞ and profile steepness p) and the flow parameters (its magnitude U0 and profile steepness u). Results: For either profile, introducing a flow reduces Pmax obtainable in the trapped regime relative to the static case. The value of Pmax is sensitive to p for profile N, but is insensitive to p for profile E. By far the most important effect a flow introduces is to reduce the capability for loops to trap standing sausage modes: (L/a)cutoff may be substantially reduced in the case with flow relative to the static one. In addition, (L/a)cutoff is smaller for a stronger flow, and for a steeper flow profile when the flow magnitude is fixed. Conclusions: If the density distribution can be described by profile N, then measuring the sausage mode period can help deduce the density profile steepness. However, this practice is not feasible if profile E more accurately describes the density distribution. Furthermore, even field-aligned flows with magnitudes substantially smaller than the ambient Alfvén speed can make coronal loops considerably less likely to support trapped standing sausage modes. Appendix A is available in

  2. Coronal Abundance Anomalies in Solar-Like Stars

    Science.gov (United States)

    Laming, John

    We propose to model the trend of coronal abundance anomalies observed in a sample of solar-like stars by Wood & Linsky (2010). Dwarf stars of similar spectral type to the Sun show what has become known as a FIP (First Ionization Potential) Effect, where elements with first ionization potential below about 10 eV are enhanced in abundance in the corona by a factor of about 3 - 4. Stars of later spectral type show a diminished FIP effect, with the anomaly disappearing at about K5 spectral type. Beyond this, M dwarf stars show an inverse FIP effect, with the low FIP ions becoming depleted in the stellar corona, by factors of order 2.5 - 3. The solar case of positive FIP effect has been successfully interpreted as being due to the action of the ponderomotive force associated with chromospheric Alfven waves. In conditions in which upgoing Alfven waves are transmitted into coronal loops, or in which coronally generated waves reflect at loop footpoints, the ponderomotive force is directed upwards, and accelerates chromospheric ions (the low FIP elements) into the corona. Neutral atoms are not affected. The inverse FIP effect can arise when upward propagating chromospheric Alfven waves are reflected back down again at coronal loop footpoints, due to a mismatch between the wave frequency and the loop resonance. We propose to study stars for which parameters like asteroseismic oscillation frequencies, coronal abundance anomalies, and chromospheric structure are known. As well as constraining coronal magnetic fields and loop resonances in these stars, we expect important insights into the nature of stellar dynamos since the M dwarfs in the sample (with inverse FIP effect) are at or near the fully convective limit. Finally, we will be able to assess potential fractionation in the O/Ne abundance ratio. Drake & Testa (2005) argued that Ne is depleted in the solar corona relative to O, but not in the coronae of more active stars. Our FIP models provide some support for this in the

  3. Axial flow positive displacement worm compressor

    Science.gov (United States)

    Murrow, Kurt David (Inventor); Giffin, Rollin George (Inventor); Fakunle, Oladapo (Inventor)

    2010-01-01

    An axial flow positive displacement compressor has an inlet axially spaced apart and upstream from an outlet. Inner and outer bodies have offset inner and outer axes extend from the inlet to the outlet through first and second sections of a compressor assembly in serial downstream flow relationship. At least one of the bodies is rotatable about its axis. The inner and outer bodies have intermeshed inner and outer helical blades wound about the inner and outer axes respectively. The inner and outer helical blades extend radially outwardly and inwardly respectively. The helical blades have first and second twist slopes in the first and second sections respectively. The first twist slopes are less than the second twist slopes. An engine including the compressor has in downstream serial flow relationship from the compressor a combustor and a high pressure turbine drivingly connected to the compressor by a high pressure shaft.

  4. Direct optical nanoscopy with axially localized detection

    CERN Document Server

    Bourg, N; Dupuis, G; Barroca, T; Bon, P; Lécart, S; Fort, E; Lévêque-Fort, S

    2014-01-01

    Evanescent light excitation is widely used in super-resolution fluorescence microscopy to confine light and reduce background noise. Herein we propose a method of exploiting evanescent light in the context of emission. When a fluorophore is located in close proximity to a medium with a higher refractive index, its near-field component is converted into light that propagates beyond the critical angle. This so-called Supercritical Angle Fluorescence (SAF) can be captured using a hig-NA objective and used to determine the axial position of the fluorophore with nanometer precision. We introduce a new technique for 3D nanoscopy that combines direct STochastic Optical Reconstruction Microscopy (dSTORM) imaging with dedicated detection of SAF emission. We demonstrate that our approach of a Direct Optical Nanoscopy with Axially Localized Detection (DONALD) yields a typical isotropic 3D localization precision of 20 nm.

  5. Piping inspection carriage having axially displaceable sensor

    Science.gov (United States)

    Zollinger, William T.; Treanor, Richard C.

    1994-01-01

    A pipe inspection instrument carriage for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure.

  6. Multimode interaction in axially excited cylindrical shells

    OpenAIRE

    2014-01-01

    Cylindrical shells exhibit a dense frequency spectrum, especially near the lowest frequency range. In addition, due to the circumferential symmetry, frequencies occur in pairs. So, in the vicinity of the lowest natural frequencies, several equal or nearly equal frequencies may occur, leading to a complex dynamic behavior. So, the aim of the present work is to investigate the dynamic behavior and stability of cylindrical shells under axial forcing with multiple equal or nearly equal natural fr...

  7. Axial flux permanent magnet brushless machines

    CERN Document Server

    Gieras, Jacek F; Kamper, Maarten J

    2008-01-01

    Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators

  8. Consistent formulation of the spacelike axial gauge

    Energy Technology Data Exchange (ETDEWEB)

    Burnel, A.; Van der Rest-Jaspers, M.

    1983-12-15

    The usual formulation of the spacelike axial gauge is afflicted with the difficulty that the metric is indefinite while no ghost is involved. We solve this difficulty by introducing a ghost whose elimination is such that the metric becomes positive for physical states. The technique consists in the replacement of the gauge condition nxA = 0 by the weaker one partial/sub 0/nxAroughly-equal0.

  9. Direct optical nanoscopy with axially localized detection

    Science.gov (United States)

    Bourg, N.; Mayet, C.; Dupuis, G.; Barroca, T.; Bon, P.; Lécart, S.; Fort, E.; Lévêque-Fort, S.

    2015-09-01

    Evanescent light excitation is widely used in super-resolution fluorescence microscopy to confine light and reduce background noise. Here, we propose a method of exploiting evanescent light in the context of emission. When a fluorophore is located in close proximity to a medium with a higher refractive index, its near-field component is converted into light that propagates beyond the critical angle. This so-called supercritical-angle fluorescence can be captured using a high-numerical-aperture objective and used to determine the axial position of the fluorophore with nanometre precision. We introduce a new technique for three-dimensional nanoscopy that combines direct stochastic optical reconstruction microscopy (dSTORM) with dedicated detection of supercritical-angle fluorescence emission. We demonstrate that our approach of direct optical nanoscopy with axially localized detection (DONALD) typically yields an isotropic three-dimensional localization precision of 20 nm within an axial range of ∼150 nm above the coverslip.

  10. Golimumab for the treatment of axial spondyloarthritis.

    Science.gov (United States)

    Gelfer, Gita; Perry, Lisa; Deodhar, Atul

    2016-01-01

    Axial spondyloarthritis (axSpA) is a chronic, immune-mediated inflammatory disease of the axial skeleton that includes ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). Patients with AS experience chronic pain due to sacroiliac joint and spinal inflammation, and may develop spinal ankylosing with syndesmophyte formation. Tumor necrosis factor α inhibitors (TNFi) have shown promise in the management of AS and axSpA by targeting the underlying inflammatory process, and providing symptomatic relief. Whether they alter the progression of the disease is uncertain. Golimumab is a fully human IgG1 monoclonal antibody that targets and downregulates the pro-inflammatory cytokine TNF-α. The use of golimumab has been shown to reduce the signs and symptoms of axSpA as well as improve patient function and quality reported outcomes. This review focuses on the biological rationale and the results of clinical trials with golimumab for the treatment of axSpA.

  11. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and a Coronal Streamer Area (6-40 R(radius symbol)

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Total electron content data obtained from the Ulysses Solar Corona Experiment (SCE) in 1991 were used to select two data sets, one associated with a coronal hole and the other with coronal streamer crossings. (This is largely equatorial data shortly after solar maximum.) The solar wind velocity profile is estimated for these areas.

  12. Energetic characterisation and statistics of solar coronal brightenings

    CERN Document Server

    Joulin, Vincent; Solomon, Jacques; Guennou, Chloé

    2016-01-01

    To explain the high temperature of the corona, much attention has been paid to the distribution of energy in dissipation events. Indeed, if the event energy distribution is steep enough, the smallest, unobservable events could be the largest contributors to the total energy dissipation in the corona. Previous observations have shown a wide distribution of energies but remain inconclusive about the precise slope. Furthermore, these results rely on a very crude estimate of the energy. On the other hand, more detailed spectroscopic studies of structures such as coronal bright points do not provide enough statistical information to derive their total contribution to heating. We aim at getting a better estimate of the distributions of the energy dissipated in coronal heating events using high-resolution, multi-channel Extreme Ultra-Violet (EUV) data. To estimate the energies corresponding to heating events and deduce their distribution, we detect brightenings in five EUV channels of the Atmospheric Imaging Assembl...

  13. Spatial damping of propagating sausage waves in coronal cylinders

    CERN Document Server

    Guo, Ming-Zhe; Li, Bo; Xia, Li-Dong; Yu, Hui

    2015-01-01

    Sausage modes are important in coronal seismology. Spatially damped propagating sausage waves were recently observed in the solar atmosphere. We examine how wave leakage influences the spatial damping of sausage waves propagating along coronal structures modeled by a cylindrical density enhancement embedded in a uniform magnetic field. Working in the framework of cold magnetohydrodynamics, we solve the dispersion relation (DR) governing sausage waves for complex-valued longitudinal wavenumber $k$ at given real angular frequencies $\\omega$. For validation purposes, we also provide analytical approximations to the DR in the low-frequency limit and in the vicinity of $\\omega_{\\rm c}$, the critical angular frequency separating trapped from leaky waves. In contrast to the standing case, propagating sausage waves are allowed for $\\omega$ much lower than $\\omega_{\\rm c}$. However, while able to direct their energy upwards, these low-frequency waves are subject to substantial spatial attenuation. The spatial damping ...

  14. Coronal heating by the partial relaxation of twisted loops

    CERN Document Server

    Bareford, Michael; Browning, Philippa

    2012-01-01

    Context: Relaxation theory offers a straightforward method for estimating the energy that is released when a magnetic field becomes unstable, as a result of continual convective driving. Aims: We present new results obtained from nonlinear magnetohydrodynamic (MHD) simulations of idealised coronal loops. The purpose of this work is to determine whether or not the simulation results agree with Taylor relaxation, which will require a modified version of relaxation theory applicable to unbounded field configurations. Methods: A three-dimensional (3D) MHD Lagrangian-remap code is used to simulate the evolution of a line-tied cylindrical coronal loop model. This model comprises three concentric layers surrounded by a potential envelope; hence, being twisted locally, each loop configuration is distinguished by a piecewise-constant current profile. Initially, all configurations carry zero-net-current fields and are in ideally unstable equilibrium. The simulation results are compared with the predictions of helicity ...

  15. Nonlinear Dynamics of the Parker Scenario for Coronal Heating

    CERN Document Server

    Rappazzo, A F; Einaudi, G; Dahlburg, R B

    2007-01-01

    The Parker or field line tangling model of coronal heating is studied comprehensively via long-time high-resolution simulations of the dynamics of a coronal loop in cartesian geometry within the framework of reduced magnetohydrodynamics (RMHD). Slow photospheric motions induce a Poynting flux which saturates by driving an anisotropic turbulent cascade dominated by magnetic energy. In physical space this corresponds to a magnetic topology where magnetic field lines are barely entangled, nevertheless current sheets (corresponding to the original tangential discontinuities hypothesized by Parker) are continuously formed and dissipated. Current sheets are the result of the nonlinear cascade that transfers energy from the scale of convective motions ($\\sim 1,000 km$) down to the dissipative scales, where it is finally converted to heat and/or particle acceleration. Current sheets constitute the dissipative structure of the system, and the associated magnetic reconnection gives rise to impulsive ``bursty'' heating ...

  16. On The Fourier And Wavelet Analysis Of Coronal Time Series

    CERN Document Server

    Auchère, F; Bocchialini, K; Buchlin, E; Solomon, J

    2016-01-01

    Using Fourier and wavelet analysis, we critically re-assess the significance of our detection of periodic pulsations in coronal loops. We show that the proper identification of the frequency dependence and statistical properties of the different components of the power spectra provies a strong argument against the common practice of data detrending, which tends to produce spurious detections around the cut-off frequency of the filter. In addition, the white and red noise models built into the widely used wavelet code of Torrence & Compo cannot, in most cases, adequately represent the power spectra of coronal time series, thus also possibly causing false positives. Both effects suggest that several reports of periodic phenomena should be re-examined. The Torrence & Compo code nonetheless effectively computes rigorous confidence levels if provided with pertinent models of mean power spectra, and we describe the appropriate manner in which to call its core routines. We recall the meaning of the default c...

  17. Estimate of Coronal Magnetic Field Strength Using Plasmoid Acceleration Measurement

    Science.gov (United States)

    Choe, G.; Lee, K.; Jang, M.

    2010-12-01

    A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. A rather simple calculation shows that the vertical force acting on a cylinder-like volume, whose lateral surface is a flux surface and whose magnetic axis is parallel to the horizontal, is just the difference in total pressure (magnetic pressure plus plasma pressure) below and above the volume. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.

  18. Coronal Mass Ejections and Non-recurrent Forbush Decreases

    Science.gov (United States)

    Belov, A.; Abunin, A.; Abunina, M.; Eroshenko, E.; Oleneva, V.; Yanke, V.; Papaioannou, A.; Mavromichalaki, H.; Gopalswamy, N.; Yashiro, S.

    2014-10-01

    Coronal mass ejections (CMEs) and their interplanetary counterparts (interplanetary coronal mass ejections, ICMEs) are responsible for large solar energetic particle events and severe geomagnetic storms. They can modulate the intensity of Galactic cosmic rays, resulting in non-recurrent Forbush decreases (FDs). We investigate the connection between CME manifestations and FDs. We used specially processed data from the worldwide neutron monitor network to pinpoint the characteristics of the recorded FDs together with CME-related data from the detailed online catalog based upon the Solar and Heliospheric Observatory (SOHO)/ Large Angle and Spectrometric Coronagraph (LASCO) data. We report on the correlations of the FD magnitude to the CME initial speed, the ICME transit speed, and the maximum solar wind speed. Comparisons between the features of CMEs (mass, width, velocity) and the characteristics of FDs are also discussed. FD features for halo, partial halo, and non-halo CMEs are presented and discussed.

  19. Polar Coronal Holes During Solar Cycles 22 and 23

    Institute of Scientific and Technical Information of China (English)

    Jun Zhang; J. Woch; S. Solanki

    2005-01-01

    Data from the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses and synoptic maps from Kitt Peak are used to analyze the polar coronal holes of solar activity cycles 22 and 23 (from 1990 to end of 2003). In the beginning of the declining phase of solar cycles 22 and 23, the north polar coronal holes (PCHs) appear about one year earlier than the ones in the south polar region.The solar wind velocity and the solar wind ionic charge composition exhibit a characteristic dependence on the solar wind source position within a PCH. From the center toward the boundary of a young PCH, the solar wind velocity decreases,coinciding with a shift of the ionic charge composition toward higher charge states.However, for an old PCH, the ionic charge composition does not show any obvious change, although the latitude evolution of the velocity is similar to that of a young PCH.

  20. Global Alfven Waves in Solar Physics: Coronal Heating

    Science.gov (United States)

    de Azevedo, C. A.; de Assis, A. S.

    1990-11-01

    RESUMEN. Se ha demostrado que Ia onda discreta de Alfven puede generar por lo memos un 20% de la energia coronal requerida con densidad de flujo de lO- erg 5 . Las ondas discretas de Alfven son una nueva clase `de ondas de Alfven las cuales pueden describirse por el modelo con que incluye un i6n finito, con frecuencia ciclotr6nica ( /uci # 0) y los efectos del equilibrio de plasma mostrados por Appert, Vaclavik and Villar 1984. ABSTRACT. It has been shown that the Discrete Alfven wave can power at least 20% of the required coronal energy flux density iO- Discrete Alfven waves are a new class of Alfven waves wich can be described by the model with the inclusion of finite ion cyclotron frequency (w/wci 0) and the equilibrium plasma current effects as shown by Appert, Vaclavik and Villar 1984. o,t :, HYDROMAGNETICS - SUN-CORONA