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Sample records for caudolateral curvilinear osteophyte

  1. ANTERIOR OSTEOPHYTE IDENTIFICATION IN CERVICAL VERTEBRAE

    Directory of Open Access Journals (Sweden)

    A. T. Chougale

    2011-06-01

    Full Text Available Radiologist always examines X-ray to determine abnormal changes in cervical, lumbar & thoracic vertebrae. Osteophyte (bony growth may appear at the corners of vertebrae so that vertebral shape becomes abnormal. This paper presents the idea from Image processing techniques such as customised Hough transform which will be used for segmentation which should be independent of rotation, scale, noise & shape. This segmented image will be then used for computing size invariant, convex hull based features to differentiate normal cervical vertebrae from cervical vertebrae containing anterior osteophyte. This approach effectively finds anterior osteophytes in cervical vertebrae.

  2. Direction of the formation of anterior lumbar vertebral osteophytes

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    Akeda Koji

    2009-01-01

    Full Text Available Abstract Background X-ray images of lumbar degenerative diseases often show not only claw osteophytes, but also pairs of osteophytes that form in a direction away from the adjacent disc. We have investigated the direction of the formation of anterior lumbar vertebral osteophytes across the lumbar vertebrae using a sufficient number of lumbar radiographs, because osteophytes images can provide essential information that will contribute to the understanding of the pathology and progress of lumbar spine degeneration. Methods The direction of the formation of 14,250 pairs of anterior lumbar vertebral osteophytes across the adjacent intervertebral discs in 2,850 patients who were all over 60 years old was investigated. Anterior lumbar vertebral osteophytes were distributed into six groups based on the direction of extension of each pair of osteophytes across the intervertebral disc space. Results In L1–L2 and L2–L3, the number of patients classified into groups B (the pair of osteophytes extended in the direction of the adjacent disc and C (almost complete bone bridge formation by a pair of osteophytes across the intervertebral disc space was larger than that classified into group D (the pair of osteophytes extended in a direction away from the adjacent disc. In L3–L4, L4–L5 and L5-S1, the number of patients in group D was greater than that of patients belonging to groups B and C. Conclusion Our study showed that pairs of osteophytes frequently formed in the direction of the adjacent disc in the upper lumbar vertebrae (L1–L2 and L2–L3 and in the direction away from the adjacent disc in middle or lower lumbar vertebrae (L3–L4, L4–L5, and L5-S1.

  3. The role of phonophoresis in dyshpagia due to cervical osteophytes

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    Zeliha Unlu

    2008-08-01

    Full Text Available Zeliha Unlu1, Sebnem Orguc2, Gorkem Eskiizmir3, Asim Aslan3, Saliha Tasci11Department of Physical Medicine and Rehabilitation; 2Department of Radiology; 3Department of Otorhinolaryngology, Celal Bayar University School of Medicine, Manisa, TurkeyObjective: Treatment of patients with anterior cervical osteophytes causing dysphagia includes conservative treatment with anti-inflammatory drugs, muscle relaxants, antibiotics, and an appropriate soft diet. Physical therapy with its advantages may be an alternative method in the treatment, which was not reported previously.Case description: Phonophoresis therapy is applied in nine patients with dysphagia due to cervical osteophytes.Results: The symptom of dysphagia regressed in various degrees in all patients after phonophoresis therapy.Conclusions: Phonophoresis might be an alternative method for the non-steroidal anti-inflammatory drug (NSAID treatment in patients with dysphagia due to cervical osteophytes.Keywords: cervical, osteophyte, dysphagia, physical therapy

  4. Dysphagia produced by cervical spine osteophyte. A case report

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    Claudio Silveri

    2014-01-01

    Full Text Available We present a case of a 73-year-old male patient with progressive dysphagia, and hoarseness (irritability in the throat. He was studied with the appropriate imaging techniques, and esophagoscopy led to a diagnosis of extrinsic esophageal dysphagia for osteophyte obstruction of the cervical spine due to the arthrosis. A surgical resection was performed, without complications. Some considerations are given on this theme.

  5. Anterior Cervical Osteophytes Causing Dysphagia and Paradoxical Vocal Cord Motion Leading to Dyspnea and Dysphonia

    OpenAIRE

    Seo, Joon Won; Park, Ji Woong; Jang, Jae Chil; Kim, Jae Wook; Lee, Yang Gyun; Kim, Yun Tae; Lee, Seok Min

    2013-01-01

    Anterior cervical osteophytes are common and usually asymptomatic in elderly people. Due to mechanical compressions, inflammations, and tissues swelling of osteophytes, patients may be presented with multiple complications, such as dysphagia, dysphonia, dyspnea, and pulmonary aspiration. Paradoxical vocal cord motion is an uncommon disease characterized by vocal cord adductions during inspiration and/or expiration. This condition can create shortness of breath, wheezing, respiratory stridor o...

  6. Periarticular osteophytes as an appendicular joint stress marker (JSM: analysis in a contemporary Japanese skeletal collection.

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    Toshiyuki Tsurumoto

    Full Text Available OBJECTIVE: The aim of this study was to investigate the possibility that periarticular osteophytes plays a role as a appendicular joint stress marker (JSM which reflects the biomechanical stresses on individuals and populations. METHODS: A total of 366 contemporary Japanese skeletons (231 males, 135 females were examined closely to evaluate the periarticular osteophytes of six major joints, the shoulder, elbow, wrist, hip, knee, and ankle and osteophyte scores (OS were determined using an original grading system. These scores were aggregated and analyzed statistically from some viewpoints. RESULTS: All of the OS for the respective joints were correlated logarithmically with the age-at-death of the individuals. For 70 individuals, in whom both sides of all six joints were evaluated without missing values, the age-standardized OS were calculated. A right side dominancy was recognized in the joints of the upper extremities, shoulder and wrist joints, and the bilateral correlations were large in the three joints on the lower extremity. For the shoulder joint and the hip joint, it was inferred by some distinctions that systemic factors were relatively large. All of these six joints could be assorted by the extent of systemic and local factors on osteophytes formation. Moreover, when the age-standardized OS of all the joints was summed up, some individuals had significantly high total scores, and others had significantly low total scores; namely, all of the individuals varied greatly in their systemic predisposition for osteophytes formation. CONCLUSIONS: This study demonstrated the significance of periarticular osteophytes; the evaluating system for OS could be used to detect differences among joints and individuals. Periarticular osteophytes could be applied as an appendicular joint stress marker (JSM; by applying OS evaluating system for skeletal populations, intra-skeletal and inter-skeletal variations in biomechanical stresses throughout the

  7. Does Early Environmental Complexity Influence Tyrosine Hydroxylase in the Chicken Hippocampus and “Prefrontal” Caudolateral Nidopallium?

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    Tahamtani, Fernanda M.; Nordgreen, Janicke; Brantsæter, Margrethe; Østby, Gunn C.; Nordquist, Rebecca E.; Janczak, Andrew M.

    2016-01-01

    In adult chickens, the housing system influences hippocampal morphology and neurochemistry. However, no work has been done investigating the effects of the early life environment on chicken brain development. In the present study, we reared 67 commercial laying hens (Gallus gallus domesticus) in two environments that differed in the degree of complexity (aviary or cage system). These two groups were further divided into two age groups. At 20 weeks of age, 18 aviary-reared birds and 15 cage-reared birds were humanely euthanized and their brains dissected. At 24 weeks of age, a further 16 brains from aviary-reared birds and 18 brains from cage-reared birds were collected. These brains were prepared for immunohistochemical detection of tyrosine hydroxylase (TH), the rate-limiting enzyme in the biosynthesis of dopamine, in the hippocampus and the caudolateral nidopallium (NCL). There were no differences between the treatment groups in TH staining intensity in the hippocampus or the NCL. In the medial hippocampus, the right hemisphere had higher TH staining intensity compared to the left hemisphere. The opposite was true for the NCL, with the left hemisphere being more strongly stained compared to the right hemisphere. The present study supports the notion that the hippocampus is functionally lateralized, and our findings add to the body of knowledge on adult neural plasticity of the avian brain. PMID:26904550

  8. Partial Arc Curvilinear Direct Drive Servomotor

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    Sun, Xiuhong (Inventor)

    2014-01-01

    A partial arc servomotor assembly having a curvilinear U-channel with two parallel rare earth permanent magnet plates facing each other and a pivoted ironless three phase coil armature winding moves between the plates. An encoder read head is fixed to a mounting plate above the coil armature winding and a curvilinear encoder scale is curved to be co-axis with the curvilinear U-channel permanent magnet track formed by the permanent magnet plates. Driven by a set of miniaturized power electronics devices closely looped with a positioning feedback encoder, the angular position and velocity of the pivoted payload is programmable and precisely controlled.

  9. Modeling of curvilinear suspension flows

    Science.gov (United States)

    Morris, Jeffrey F.; Boulay, Fabienne

    1996-11-01

    The curvilinear parallel-plate and cone-and-plate rheometric flows of monodisperse noncolloidal suspensions have been modeled. Although nonuniform in shear rate, dotγ, the parallel-plate flow has been shown experimentally(A. W. Chow, S. W. Sinton, J. H. Iwayima & T. S. Stephens 1994 Phys. Fluids) 6, 2561. not to exhibit particle migration, contrary to predictions of prior suspension-flow modeling. Predictions of nonuniform particle volume fraction, φ, by the suspension-balance model(P. R. Nott & J. F. Brady 1994 J. Fluid Mech.) 275, 157. for parallel-plate and cone-and-plate flow without normal stress differences are presented. The ``nonmigration'' in parallel-plate flow may be attributed to bulk suspension normal stress differences: assuming the bulk stress has the form Σ ~ η dotγ Q(φ) with η the fluid viscosity, nonmigration is predicted for parallel-plate flow provided that Q_33 = (1/2) Q_11 at the bulk φ of interest, with 1 the flow direction and 3 the vorticity direction. Extending the model to include normal stress differences satisfying this requirement, a range of migration behavior is predicted for the cone-and-plate flow depending upon the ratio Q_11/Q_22.

  10. Fokker - Planck equation in curvilinear coordinates

    OpenAIRE

    Tanski, Igor A.

    2005-01-01

    The aim of this paper is to rewrite the Fokker - Planck equation according to transformation of space coordinates. This is nontrivial problem, because transformation of space coordinates induces transformation of velocities. We can use covariant, contravariant or physical velocity components as independent variables in curvilinear coordinate system. These 3 possibilities are considered in this paper and 3 kinds of Fokker - Planck equation in curvilinear coordinates are formulated.

  11. Kinematic Changes in Swallowing After Surgical Removal of Anterior Cervical Osteophyte Causing Dysphagia: A Case Series

    OpenAIRE

    Jeong, Hyeonghui; Seo, Han Gil; Han, Tai Ryoon; Chung, Chun Kee; Oh, Byung-Mo

    2014-01-01

    This retrospective case series included five patients who underwent surgical resection of the cervical anterior osteophyte due to dysphagia. Videofluoroscopic swallowing studies (VFSSs) were performed before and after surgery on each patient, and kinematic analysis of the video clips from the VFSS of a 5-mL liquid barium swallow was carried out. Functional oral intake improved after surgery in 3/4 patients who had required a modified diet before surgery. Kinematic analysis showed increases in...

  12. Superior Dislocation of the Patella in a Young Woman without Osteophytes: A Case Report.

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    Kataoka, Tatsunori; Iizawa, Norishige; Takai, Shinro

    2016-01-01

    Superior dislocation of the patella without patellar ligament injury is an extremely rare condition. A review of the English-language literature found only 23 reported cases. In addition, the primary factor for dislocation in most of these cases was considered to be osteophytes in the inferior pole of the patella and the anterior surface of the femoral condyle; only 1 case had no osteophytes. We treated a 19-year-old woman who sustained a painful locking of the left knee after colliding with a friend. Plain radiography and computed tomography showed superior-lateral dislocation of the patella and an interlocking between notches in the inferior pole of the patella and the anterior surface of the femoral condyle. Closed reduction without sedation was performed without difficulty, and the patient was able to walk home without pain. After 1 week, the knee was without problems. The patient had no osteophytes in the knee and had no other common risk factors, such as patella alta, ligamentous laxity, genu recurvatum, and paralytic disorders. After a comparison with previously reported cases of superior patella dislocation, we concluded that the primary factor in the present case might have been a different condition. PMID:26960585

  13. The Current Scenario of Curvilinear Architecture in Malaysia

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    Faridah Aduan

    2007-12-01

    Full Text Available The Bilbao Effect incorporates itself into numerous iconic buildings and grand design s of international architects such as Frank Gehry, Santiago Calatrava, Norman Foster, Renzo Piano, Phillip Cox and Toyo Ito who exploit curvilinear forms as their architectural language .Throughout the world, major events such as the Olympic Games have catalysed the implementation of curvilinear architecture while in Malaysia, the development of Putrajaya has provided opportunity for iconic forms, expressed in curvilinearity. The paper focuses on the current scenario of curvilinear architecture in Malaysia and its posit ion in the international arena. It strives to answer the question of 'How far have Malaysian architects gone in implementing curvilinear architecture?' This is done by first formulating a 'Taxonomy of Rigid Curvilinear Architectural Forms' based on the works of renowned international architects. The taxonomy constitutes the instrument for gauging the position of Malaysian architects. This is achieved by having the works of local architects mapped on to the taxonomy. The research findings indicate that the international architects have advanced by leaps and bounds ahead of their Malaysian counterparts in implementing curvilinear architecture. Several recommendations are proposed in order to narrow this gap .The paper focuses on column-free, rigid and permanent buildings completed from 1990 onwards .

  14. Proximal tibial osteophytes and their relationship with the height of the tibial spines of the intercondylar eminence: paleopathological study

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    Hayeri, Mohammad Reza [Children' s National Medical Center, Department of Radiology, Washington, DC (United States); Shiehmorteza, Masoud; Trudell, Debra J.; Resnick, Donald [University of California San Diego, Department of Radiology, San Diego, CA (United States); Hefflin, Tori [Museum of Man San Diego, San Diego, CA (United States)

    2010-09-15

    Tibial spiking (i.e., spurring of tibial spines), eburnation, and osteophytes are considered features of osteoarthritis. This investigation employed direct inspection of the medial and lateral tibial plateaus in paleopathological specimens to analyze the frequency and morphological features of osteoarthritis and to define any relationship between the size of osteophytes and that of the intercondylar tibial spines. A total of 35 tibial bone specimens were evaluated for the degree of osteoarthritis and presence of eburnation. Each plateau was also divided into four quadrants and the presence and size of bone outgrowths were recorded in each quadrant. The ''medial/lateral tibial intercondylar spine index'' for each specimen was calculated as follows: (medial/lateral intercondylar tibial spine height)/(anteroposterior width of the superior tibial surface). The relationships between medial and lateral tibial height indexes with the degree of osteoarthritis were then tested. Osteophytes were observed more frequently in the anterior quadrants of both tibial plateaus than in the posterior quadrants (29 vs 16 for the medial tibial plateau [p = 0.01] and 28 vs 20 for the lateral tibial plateau [p = 0.04]). Eburnation was seen more frequently in the posterior regions of both tibial plateaus than in the anterior regions (17 vs 5, p < 0.01). In specimens with no signs of osteoarthritis the lateral intercondylar tibial index was significantly lower than that in specimens with some degree of osteoarthritis (p = 0.02). The medial intercondylar tibial index of the specimens with no signs of osteoarthritis was not significantly different from that of the specimens with some degree of osteoarthritis (p = 0.45). There was a positive correlation between the lateral spine height index and the overall grading of osteoarthritis, (r = 0.6, p < 0.01). In the anteromedial and posteromedial quadrants of the lateral tibial plateau, the association between the lateral

  15. AN ADAPTIVE NONMONOTONIC TRUST REGION METHOD WITH CURVILINEAR SEARCHES

    Institute of Scientific and Technical Information of China (English)

    Qun-yan Zhou; Wen-yu Sun

    2006-01-01

    In this paper, an algorithm for unconstrained optimization that employs both trust region techniques and curvilinear searches is proposed. At every iteration, we solve the trust region subproblem whose radius is generated adaptively only once. Nonmonotonic backtracking curvilinear searches are performed when the solution of the subproblem is unacceptable. The global convergence and fast local convergence rate of the proposed algorithms are established under some reasonable conditions. The results of numerical experiments are reported to show the effectiveness of the proposed algorithms.

  16. A novel mathematical model for growth of capillaries and nutrient supply with application to prediction of osteophyte onset

    Science.gov (United States)

    Bednarczyk, Ewa; Lekszycki, Tomasz

    2016-08-01

    In this paper, a novel evolution equation for capillaries growth is proposed. An essential ingredient is given by the consideration of nutrient supply, for which a novel constitutive equation is also proposed. The biological and mechanical stimuli are assumed to depend in non-local way on relevant kinematical descriptors. The integro-differential equations governing the system evolution are extremely sensitive to parameter variations. However, it was possible to perform some meaningful numerical simulations in which osteophyte onset has been observed. While the choice of these parameters was judiciously driven by biomechanical "a priori" knowledge, the mathematical problems concerning well-posedness, stability and continuous dependence of solutions seem to be very challenging and will be object of future investigations. This effort seems motivated by the fact that proposed equations are, to our knowledge, the first ones allowing for the prediction of osteophytes onset.

  17. Relationship between soy milk intake and radiographic knee joint space narrowing and osteophytes.

    Science.gov (United States)

    Li, Hui; Zeng, Chao; Wei, Jie; Yang, Tuo; Gao, Shu-Guang; Li, Yu-Sheng; Luo, Wei; Xiao, Wen-Feng; Xiong, Yi-Lin; Lei, Guang-Hua

    2016-09-01

    The purpose of this study was to examine the cross-sectional association between dietary soy milk intake and the prevalence of radiographic knee joint space narrowing (JSN) and osteophytes (OST). Soy milk intake was assessed using a validated semiquantitative food frequency questionnaire and classified into three categories: never, sex), the prevalence of OST decreased in "≥once a day" category (OR 0.52, 95 % CI 0.28-0.98, P = 0.042) and "educational background, diabetes, hypertension, and other dairy product intake) ("≥once a day" category: OR 0.49, 95 % CI 0.26-0.92, P = 0.026; "

  18. NONMONOTONE PRECONDITIONAL CURVILINEAR PATH ALGORITHMS FOR UNCONSTRAINED OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    朱德通

    2003-01-01

    This paper presents nonmonotonic quasi-Newton algorithms via two pre-conditional curvilinear paths, the preconditional modified gradient path and the precon-ditional optimal path, for unconstrained optimization problem. We employ the stableBunch-Parlett factorization method to form two curvilinear paths very easily. Thenonmonotone criterion is used to speed up the convergence progress in the contoursof objective function with large curvature. Theoretical analyses are given which provethat the proposed algorithms are globally convergent and have a local superlinear con-vergence rate under some reasonable conditions. The results of numerical experimentsare reported to show the effectiveness of the proposed algorithms.

  19. Curvilinear shapes and the snake detection hypothesis : An ERP study

    NARCIS (Netherlands)

    Van Strien, Jan W; Christiaans, Gerwin; Franken, Ingmar H A; Huijding, Jorg

    2016-01-01

    Consistent with the snake detection hypothesis, previous ERP studies have established a larger early posterior negativity (EPN) in response to pictures depicting snakes than to pictures depicting other creatures. Here, we examined to what extent the curvilinear shape of the snake's body drives the l

  20. Aggressive Behavior and Quality of Friendships: Linear and Curvilinear Associations

    Science.gov (United States)

    Fanti, Kostas A.; Brookmeyer, Kathryn A.; Henrich, Christopher C.; Kuperminc, Gabriel P.

    2009-01-01

    The current study investigates linear and curvilinear associations between overt aggressive behavior and the adolescents' reports of the quality of their friendships over time. Moderation by gender was also investigated. The sample consisted of 246 boys and 253 girls from the sixth and seventh grades of a large public middle school. Findings…

  1. The modelling of plane curvilinear dipole antenna arrays

    OpenAIRE

    Hoblyk, Viktor V.; Liske, O. M.; Yakovenko, Eugenia I.

    2005-01-01

    In this work the results of mathematical model design for printed dipole antenna arrays are presented. The arrays are feeding by curvilinear  transmission slotline. The investigation is important for the antenna arrays theory and useful for the design of antenna arrays with improved characteristics.

  2. A novel curvilinear approach for prostate seed implantation

    Energy Technology Data Exchange (ETDEWEB)

    Podder, Tarun K.; Dicker, Adam P.; Hutapea, Parsaoran; Darvish, Kurosh; Yu Yan [Department of Radiation Oncology, Leo Jenkins Cancer Center, Brody School of Medicine, East Carolina University, Greenville, North Carolina 27834 (United States); Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Department of Mechanical Engineering, Temple University, Philadelphia, Pennsylvania 19122 (United States); Department of Radiation Oncology, Kimmel Cancer Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)

    2012-04-15

    Purpose: A new technique called ''curvilinear approach'' for prostate seed implantation has been proposed. The purpose of this study is to evaluate the dosimetric benefit of curvilinear distribution of seeds for low-dose-rate (LDR) prostate brachytherapy. Methods: Twenty LDR prostate brachytherapy cases planned intraoperatively with VariSeed planning system and I-125 seeds were randomly selected as reference rectilinear cases. All the cases were replanned by using curved-needle approach keeping the same individual source strength and the volume receiving 100% of prescribed dose 145 Gy (V{sub 100}). Parameters such as number of needles, seeds, and the dose coverage of the prostate (D{sub 90}, V{sub 150}, V{sub 200}), urethra (D{sub 30}, D{sub 10}) and rectum (D{sub 5}, V{sub 100}) were compared for the rectilinear and the curvilinear methods. Statistical significance was assessed using two-tailed student's t-test. Results: Reduction of the required number of needles and seeds in curvilinear method were 30.5% (p < 0.001) and 11.8% (p < 0.49), respectively. Dose to the urethra was reduced significantly; D{sub 30} reduced by 10.1% (p < 0.01) and D{sub 10} reduced by 9.9% (p < 0.02). Reduction in rectum dose D{sub 5} was 18.5% (p < 0.03) and V{sub 100} was also reduced from 0.93 cc in rectilinear to 0.21 cc in curvilinear (p < 0.001). Also the V{sub 150} and V{sub 200} coverage of prostate reduced by 18.8% (p < 0.01) and 33.9% (p < 0.001), respectively. Conclusions: Significant improvement in the relevant dosimetric parameters was observed in curvilinear needle approach. Prostate dose homogeneity (V{sub 150}, V{sub 200}) improved while urethral dose was reduced, which might potentially result in better treatment outcome. Reduction in rectal dose could potentially reduce rectal toxicity and complications. Reduction in number of needles would minimize edema and thereby could improve postimplant urinary incontinence. This study indicates that the

  3. A new osteophyte segmentation method with applications to an anterior cruciate ligament transection rabbit femur model via micro-CT imaging

    Science.gov (United States)

    Liang, G.; Elkins, J. M.; Coimbra, A.; Duong, L. T.; Williams, D. S.; Sonka, M.; Saha, P. K.

    2010-03-01

    Osteophyte is an additional bony growth on a normal bone surface limiting or stopping motion in a deteriorating joint. Detection and quantification of osteophytes from CT images is helpful in assessing disease status as well as treatment and surgery planning. However, it is difficult to segment osteophytes from healthy bones using simple thresholding or edge/texture features in CT imaging. Here, we present a new method, based on active shape model (ASM), to solve this problem and evaluate its application to ex vivo μCT images in an ACLT rabbit femur model. The common idea behind most ASM based segmentation methods is to first build a parametric shape model from a training dataset and during application, find a shape instance from the model that optimally fits to target image. However, it poses a fundamental difficulty for the current application because a diseased bone shape is significantly altered at regions with osteophyte deposition misguiding an ASM method that eventually leads to suboptimum segmentation results. Here, we introduce a new partial ASM method that uses bone shape over healthy regions and extrapolate its shape over diseased region following the underlying shape model. Once the healthy bone region is detected, osteophyte is segmented by subtracting partial-ASM derived shape from the overall diseased shape. Also, a new semi-automatic method is presented in this paper for efficiently building a 3D shape model for rabbit femur. The method has been applied to μCT images of 2-, 4-, and 8-week post ACLT and sham-treated rabbit femurs and results of reproducibility and sensitivity analyses of the new osteophyte segmentation method are presented.

  4. Linear and/or curvilinear rail mount system

    Science.gov (United States)

    Thomas, Jackie D. (Inventor); Harris, Lawanna L. (Inventor)

    2012-01-01

    One or more linear and/or curvilinear mounting rails are coupled to a structure. Each mounting rail defines a channel and at least one cartridge assembly is engaged in the channel. Each cartridge assembly includes a housing that slides within the channel. The housing defines a curvilinearly-shaped recess longitudinally aligned with the channel when the housing is in engagement therewith. The cartridge assembly also includes a cleat fitted in the recess for sliding engagement therealong. The cleat can be coupled to a fastener that passes through the mounting rail and the housing when the housing is so-engaged in the channel. The cleat is positioned in the recess by a position of the fastener.

  5. Reconstructing Wireframe Model of Curvilinear Objects from Three Orthographic Views

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An approach for reconstructing wireframe models of curvilinear objects from three orthographic views is discussed in this paper. The method for generating 3D conic edges from 2D projection conic curves is emphasized especially, which is the pivotal work for reconstructing curvilinear objects from three orthographic views. In order to generate 3D conic edges, a five-point method is firstly utilized to obtain the algebraic representations of all 2D-projection curves in each view, and then all algebraic forms are converted to the corresponding geometric forms analytically. Thus the locus of a 3D conic edge can be derived from the geometric forms of the relevant conic curves in three views. Finally, the wireframe model is created after eliminating all redundant elements generated in previous reconstruction process. The approach extends the range of objects to be reconstructed and imposes no restriction on the axis of the quadric surface.

  6. Electron as the eigenstate of curvilinear space with torsion

    Science.gov (United States)

    Sharin, Yu. A.

    1998-05-01

    Ideas previously enunciated by the author about the physical interpretation of curvilinear space with torsion are developed. With the new equations describing the eigenstates of such a space, the static centrosymmetric solution for gravitational and electric fields can be made consistent with the Newton and Coulomb laws. The asymptotic behavior of the axisymmetric solution at infinity is studied. The gyromagnetic ratio obtained is characteristic of the electron.

  7. TGF-ß in osteoarthritis : age-related loss of protective function in cartilage and player in osteophyte formation and synovial fibrosis

    NARCIS (Netherlands)

    Blaney Davidson, Esmeralda Nicole

    2007-01-01

    Osteoarthritis (OA) is a common joint disease affecting mainly the elderly population. In younger people it can be caused by joint trauma or congenital afflictions. OA is characterized by cartilage damage, synovial fibrosis and osteophyte formation. TGF-ß is a growth factor that is a potent inducer

  8. GAIA: A 2-D Curvilinear moving grid hydrodynamic code

    International Nuclear Information System (INIS)

    The GAIA computer code is developed for time dependent, compressible, multimaterial fluid flow problems, to overcome some drawbacks of traditional 2-D Lagrangian codes. The initial goals of robustness, entropy accuracies, efficiency in presence of large interfacial slip, have already been achieved. The general GODUNOV approach is applied to an arbitrary time varying control-volume formulation. We review in this paper the Riemann solver, the GODUNOV cartesian and curvilinear moving grid schemes and an efficient grid generation algorithm. We finally outline a possible second order accuracy extension

  9. Comparison of Curvilinear Stiffeners and Tow Steered Composites for Aeroelastic Tailoring of Transports

    Science.gov (United States)

    Stanford, Bret K.; Jutte, Christine V.

    2016-01-01

    A series of aeroelastic optimization problems are solved on a high aspect ratio wingbox of the Common Research Model, in an effort to minimize structural mass under coupled stress, buckling, and flutter constraints. Two technologies are of particular interest: tow steered composite laminate skins and curvilinear stiffeners. Both methods are found to afford feasible reductions in mass over their non-curvilinear structural counterparts, through both distinct and shared mechanisms for passively controlling aeroelastic performance. Some degree of diminishing returns are seen when curvilinear stiffeners and curvilinear fiber tow paths are used simultaneously.

  10. 3-T MRI assessment of osteophyte formation in patients with unilateral anterior cruciate ligament injury and reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Panzer, Stephanie [Department of Radiology, Trauma Center Murnau, Murnau (Germany); Augat, Peter [Trauma Center Murnau and Paracelsus Medical University, Institute of Biomechanics, Murnau (Germany); Atzwanger, Joerg; Hergan, Klaus [University Hospital Salzburg, Paracelsus Medical University, Department of Radiology, Salzburg (Austria)

    2012-12-15

    To define the number and distribution of osteophytes (OPs) in bilateral knee MRI (magnetic resonance imaging) of patients with unilateral anterior cruciate ligament (ACL) rupture. Bilateral knee MRIs of 20 patients with unilateral ACL rupture and reconstruction were retrospectively analyzed for OPs. OPs were graded following the KOSS (knee OA scoring system) classification and their compartmental distribution was assessed following the WORMS (Whole-Organ Magnetic Resonance Imaging Score) classification. All examined knees revealed OPs. Knees with ACL rupture showed significant (p < 0.001) higher total numbers of OPs (mean 11.6; SD {+-} 4.4) than knees with intact ACL (mean 5.1; SD {+-} 2.3). Knees with ACL rupture showed increased OP formation in all knee compartments with predominance of marginal OPs in the lateral femorotibial compartment especially on the tibia. Our results show that after knee injury with ACL rupture and reconstruction, all knee compartments were involved in post-traumatic increase of OP formation. The most affected compartment was the lateral femorotibial compartment on the tibial side. (orig.)

  11. Temporal mammogram image registration using optimized curvilinear coordinates.

    Science.gov (United States)

    Abdel-Nasser, Mohamed; Moreno, Antonio; Puig, Domenec

    2016-04-01

    Registration of mammograms plays an important role in breast cancer computer-aided diagnosis systems. Radiologists usually compare mammogram images in order to detect abnormalities. The comparison of mammograms requires a registration between them. A temporal mammogram registration method is proposed in this paper. It is based on the curvilinear coordinates, which are utilized to cope both with global and local deformations in the breast area. Temporal mammogram pairs are used to validate the proposed method. After registration, the similarity between the mammograms is maximized, and the distance between manually defined landmarks is decreased. In addition, a thorough comparison with the state-of-the-art mammogram registration methods is performed to show its effectiveness.

  12. Differential Geometrically Consistent Artificial Viscosity in Comoving Curvilinear Coordinates

    CERN Document Server

    Höller, Harald; Dorfi, Ernst; Benger, Werner

    2013-01-01

    Context. High-resolution numerical methods have been developed for nonlinear, discontinuous problems as they appear in simulations of astrophysical objects. One of the strategies applied is the concept of artificial viscosity. Aims. Grid-based numerical simulations ideally utilize problem-oriented grids in order to minimize the necessary number of cells at a given (desired) spatial resolution. We want to propose a modified tensor of artificial viscosity which is employable for generally comoving, curvilinear grids. Methods. We study a differential geometrically consistent artificial viscosity analytically and visualize a comparison of our result to previous implementations by applying it to a simple self-similar velocity field. We give a general introduction to artificial viscosity first and motivate its application in numerical analysis. Then we present how a tensor of artificial viscosity has to be designed when going beyond common static Eulerian or Lagrangian comoving rectangular grids. Results. We find t...

  13. Dendritic spine detection using curvilinear structure detector and LDA classifier.

    Science.gov (United States)

    Zhang, Yong; Zhou, Xiaobo; Witt, Rochelle M; Sabatini, Bernardo L; Adjeroh, Donald; Wong, Stephen T C

    2007-06-01

    Dendritic spines are small, bulbous cellular compartments that carry synapses. Biologists have been studying the biochemical pathways by examining the morphological and statistical changes of the dendritic spines at the intracellular level. In this paper a novel approach is presented for automated detection of dendritic spines in neuron images. The dendritic spines are recognized as small objects of variable shape attached or detached to multiple dendritic backbones in the 2D projection of the image stack along the optical direction. We extend the curvilinear structure detector to extract the boundaries as well as the centerlines for the dendritic backbones and spines. We further build a classifier using Linear Discriminate Analysis (LDA) to classify the attached spines into valid and invalid types to improve the accuracy of the spine detection. We evaluate the proposed approach by comparing with the manual results in terms of backbone length, spine number, spine length, and spine density.

  14. Reconstruction method for curvilinear structures from two views

    Science.gov (United States)

    Hoffmann, Matthias; Brost, Alexander; Jakob, Carolin; Koch, Martin; Bourier, Felix; Kurzidim, Klaus; Hornegger, Joachim; Strobel, Norbert

    2013-03-01

    Minimally invasive interventions often involve tools of curvilinear shape like catheters and guide-wires. If the camera parameters of a fluoroscopic system or a stereoscopic endoscope are known, a 3-D reconstruction of corresponding points can be computed by triangulation. Manual identification of point correspondences is time consuming, but there exist methods that automatically select corresponding points along curvilinear structures. The focus here is on the evaluation of a recent published method for catheter reconstruction from two views. A previous evaluation of this method using clinical data yielded promising results. For that evaluation, however, no 3-D ground truth data was available such that the error could only be estimated using the forward-projection of the reconstruction. In this paper, we present a more extensive evaluation of this method based on both clinical and phantom data. For the evaluation using clinical images, 36 data sets and two different catheters were available. The mean error found when reconstructing both catheters was 0.1mm +/- 0.1mm. To evaluate the error in 3-D, images of a phantom were acquired from 13 different angulations. For the phantom, A 3D C-arm CT voxel data set of the phantom was also available. A reconstruction error was calculated by comparing the triangulated 3D reconstruction result to the 3D voxel data set. The evaluation yielded an average error of 1.2mm +/- 1.2mm for the circumferential mapping catheter and 1.3mm +/- 1.0mm for the ablation catheter.

  15. Guarding curvilinear art galleries with vertex or point guards

    CERN Document Server

    Karavelas, Menelaos I

    2008-01-01

    One of the earliest and most well known problems in computational geometry is the so-called art gallery problem. The goal is to compute the minimum possible number guards placed on the vertices of a simple polygon in such a way that they cover the interior of the polygon. In this paper we consider the problem of guarding an art gallery which is modeled as a polygon with curvilinear walls. Our main focus is on polygons the edges of which are convex arcs pointing towards the exterior or interior of the polygon (but not both), named piecewise-convex and piecewise-concave polygons. We prove that, in the case of piecewise-convex polygons, if we only allow vertex guards, $\\lfloor\\frac{4n}{7}\\rfloor-1$ guards are sometimes necessary, and $\\lfloor\\frac{2n}{3}\\rfloor$ guards are always sufficient. Moreover, an $O(n\\log{}n)$ time and $O(n)$ space algorithm is described that produces a vertex guarding set of size at most $\\lfloor\\frac{2n}{3}\\rfloor$. When we allow point guards the afore-mentioned lower bound drops down ...

  16. Profiles for voltage-activated currents are multiphasic, not curvilinear

    CERN Document Server

    Nissen, Per

    2016-01-01

    Data for voltage-activation of a potassium channel (Matulef et al. Proc Natl Acad Sci USA 110: 17886-17891. 2013) were, as conventionally done, fitted by the authors by a Boltzmann function, i.e. by a curvilinear profile. Reanalysis of the data reveals however that this interpretation must be rejected in favor of a multiphasic profile, a series of straight lines separated by discontinuous transitions, quite often in the form of noncontiguities (jumps). In contrast to the generally very poor fits to the Boltzmann profiles, the fits to multiphasic profiles are very good. (For the four replicates, the average deviations from the Boltzmann curves were 10- to 100-fold larger than the deviations from the multiphasic profiles.) The difference in the median values was statistically highly significant, P<0.001 in most cases. For the mean values the deviations from the Boltzmann curve were 20-fold larger than the deviations from the multiphasic profile, and the difference in the median values was also highly signifi...

  17. High-Order Curvilinear Finite Element Methods for Lagrangian Hydrodynamics [High Order Curvilinear Finite Elements for Lagrangian Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Dobrev, Veselin A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kolev, Tzanio V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rieben, Robert N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2012-09-20

    The numerical approximation of the Euler equations of gas dynamics in a movingLagrangian frame is at the heart of many multiphysics simulation algorithms. Here, we present a general framework for high-order Lagrangian discretization of these compressible shock hydrodynamics equations using curvilinear finite elements. This method is an extension of the approach outlined in [Dobrev et al., Internat. J. Numer. Methods Fluids, 65 (2010), pp. 1295--1310] and can be formulated for any finite dimensional approximation of the kinematic and thermodynamic fields, including generic finite elements on two- and three-dimensional meshes with triangular, quadrilateral, tetrahedral, or hexahedral zones. We discretize the kinematic variables of position and velocity using a continuous high-order basis function expansion of arbitrary polynomial degree which is obtained via a corresponding high-order parametric mapping from a standard reference element. This enables the use of curvilinear zone geometry, higher-order approximations for fields within a zone, and a pointwise definition of mass conservation which we refer to as strong mass conservation. Moreover, we discretize the internal energy using a piecewise discontinuous high-order basis function expansion which is also of arbitrary polynomial degree. This facilitates multimaterial hydrodynamics by treating material properties, such as equations of state and constitutive models, as piecewise discontinuous functions which vary within a zone. To satisfy the Rankine--Hugoniot jump conditions at a shock boundary and generate the appropriate entropy, we introduce a general tensor artificial viscosity which takes advantage of the high-order kinematic and thermodynamic information available in each zone. Finally, we apply a generic high-order time discretization process to the semidiscrete equations to develop the fully discrete numerical algorithm. Our method can be viewed as the high-order generalization of the so-called staggered

  18. Use of generalized curvilinear coordinate systems in electromagnetic and hybrid codes

    Energy Technology Data Exchange (ETDEWEB)

    Swift, D.W. [Univ. of Alaska, Fairbanks, AK (United States)

    1995-07-01

    The author develops a code to simulate the dynamics in the magnetosphere system. The calculation involves a single level, structured, curvilinear 2D mesh. The mesh density is varied to support regions which demand higher resolution.

  19. Global-local Finite Element Fracture Analysis of Curvilinearly Stiffened Panels and Adhesive Joints

    OpenAIRE

    Islam, Mohammad Majharul

    2012-01-01

    Global-local finite element analyses were used to study the damage tolerance of curvilinearly stiffened panels; fabricated using the modern additive manufacturing process, the so-called unitized structures, and that of adhesive joints. A damage tolerance study of the unitized structures requires cracks to be defined in the vicinity of the critical stress zone. With the damage tolerance study of unitized structures as the focus, responses of curvilinearly stiffened panels to the combined shear...

  20. Three-dimensional curvilinear device reconstruction from two fluoroscopic views

    Science.gov (United States)

    Delmas, Charlotte; Berger, Marie-Odile; Kerrien, Erwan; Riddell, Cyril; Trousset, Yves; Anxionnat, René; Bracard, Serge

    2015-03-01

    In interventional radiology, navigating devices under the sole guidance of fluoroscopic images inside a complex architecture of tortuous and narrow vessels like the cerebral vascular tree is a difficult task. Visualizing the device in 3D could facilitate this navigation. For curvilinear devices such as guide-wires and catheters, a 3D reconstruction may be achieved using two simultaneous fluoroscopic views, as available on a biplane acquisition system. The purpose of this paper is to present a new automatic three-dimensional curve reconstruction method that has the potential to reconstruct complex 3D curves and does not require a perfect segmentation of the endovascular device. Using epipolar geometry, our algorithm translates the point correspondence problem into a segment correspondence problem. Candidate 3D curves can be formed and evaluated independently after identifying all possible combinations of compatible 3D segments. Correspondence is then inherently solved by looking in 3D space for the most coherent curve in terms of continuity and curvature. This problem can be cast into a graph problem where the most coherent curve corresponds to the shortest path of a weighted graph. We present quantitative results of curve reconstructions performed from numerically simulated projections of tortuous 3D curves extracted from cerebral vascular trees affected with brain arteriovenous malformations as well as fluoroscopic image pairs of a guide-wire from both phantom and clinical sets. Our method was able to select the correct 3D segments in 97.5% of simulated cases thus demonstrating its ability to handle complex 3D curves and can deal with imperfect 2D segmentation.

  1. Curvilinear parabolic approximation for surface wave transformation with wave current interaction

    Science.gov (United States)

    Shi, Fengyan; Kirby, James T.

    2005-04-01

    The direct coordinate transformation method, which only transforms independent variables and retains Cartesian dependent variables, may not be an appropriate method for the purpose of simplifying the curvilinear parabolic approximation of the vector form of the wave-current equation given by Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. In this paper, the covariant-contravariant tensor method is used for the curvilinear parabolic approximation. We use the covariant components of the wave number vector and contravariant components of the current velocity vector so that the derivation of the curvilinear equation closely follows the higher-order approximation in rectangular Cartesian coordinates in Kirby [Higher-order approximations in the parabolic equation method for water waves, J. Geophys. Res. 91 (1986) 933-952]. The resulting curvilinear equation can be easily implemented using the existing model structure and numerical schemes adopted in the Cartesian parabolic wave model [J.T. Kirby, R.A. Dalrymple, F. Shi, Combined Refraction/Diffraction Model REF/DIF 1, Version 2.6. Documentation and User's Manual, Research Report, Center for Applied Coastal Research, Department of Civil and Environmental Engineering, University of Delaware, Newark, 2004]. Several examples of wave simulations in curvilinear coordinate systems, including a case with wave-current interaction, are shown with comparisons to theoretical solutions or measurement data.

  2. Approximate solutions of non-linear circular orbit relative motion in curvilinear coordinates

    Science.gov (United States)

    Bombardelli, Claudio; Gonzalo, Juan Luis; Roa, Javier

    2016-07-01

    A compact, time-explicit, approximate solution of the highly non-linear relative motion in curvilinear coordinates is provided under the assumption of circular orbit for the chief spacecraft. The rather compact, three-dimensional solution is obtained by algebraic manipulation of the individual Keplerian motions in curvilinear, rather than Cartesian coordinates, and provides analytical expressions for the secular, constant and periodic terms of each coordinate as a function of the initial relative motion conditions or relative orbital elements. Numerical test cases are conducted to show that the approximate solution can be effectively employed to extend the classical linear Clohessy-Wiltshire solution to include non-linear relative motion without significant loss of accuracy up to a limit of 0.4-0.45 in eccentricity and 40-45° in relative inclination for the follower. A very simple, quadratic extension of the classical Clohessy-Wiltshire solution in curvilinear coordinates is also presented.

  3. NUMERICAL SIMULATION OF 2D HORIZONTAL COOLING WATER DISCHARGE IN GENERALIZED CURVILINEAR COORDINATE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    2D horizontal model is one of the major mathematical methods for the research on cooling water discharge from the power plant. In this paper, the shallow water equations are transformed under the generalized curvilinear coordinate system and the elliptic differential equations are used to generate curvilinear grids, so a model in generalized curvilinear coordinate is presented to simulate 2D horizontal cooling water. Governing equations of the model are discretized by finite volume method, and non-staggered grids and SIMPLE algorithm are introduced to simplify the program during the discretization. This model is used to simulate the movement of cooling water in a simplified meandering channel and a natural channel, calculating results indicate this model can correctly reflect the movement rules of cooling water, which verifies the model can be applied in engineering practice.

  4. The movement kinematics of manipulator with elastic joints in the curvilinear coordinate system

    Directory of Open Access Journals (Sweden)

    A.A. Ghukasyan

    2007-09-01

    Full Text Available Movement kinematics of the multi-link manipulator with elastic joints in the curvilinear coordinate system is studied. Within the bounds of the linear theory of elasticity by generalized Lame matrix general expressions for speed and acceleration of the characteristic points of the links and manipulator handle are received. The received formulas allow to easily determine the kinematics of different constructions of the manipulators with elastic joints in the curvilinear coordinates. As an example movement velocity of a two-link manipulator with one elastic joint is determined in the cylindrical coordinate system.

  5. Dynamic Aspects of Voluntary Turnover: An Integrated Approach to Curvilinearity in the Performance-Turnover Relationship

    Science.gov (United States)

    Becker, William J.; Cropanzano, Russell

    2011-01-01

    Previous research pertaining to job performance and voluntary turnover has been guided by 2 distinct theoretical perspectives. First, the push-pull model proposes that there is a quadratic or curvilinear relationship existing between these 2 variables. Second, the unfolding model of turnover posits that turnover is a dynamic process and that a…

  6. Differential Parenting and Children's Behavioral Problems: Curvilinear Associations and Mother-Father Combined Effects

    Science.gov (United States)

    Meunier, Jean Christophe; Bisceglia, Rossana; Jenkins, Jennifer M.

    2012-01-01

    In this study the associations between mothers' and fathers' differential parenting and children's oppositional and emotional problems were examined. A curvilinear relationship between differential parenting and children's outcomes was hypothesized, as well as the combined effect of mothers' and fathers' parenting. Data came from a community…

  7. Stability estimates for h-p spectral element methods for general elliptic problems on curvilinear domains

    NARCIS (Netherlands)

    Dutt, Pravir; Tomar, Satyendra

    2003-01-01

    In this paper we show that the h-p spectral element method developed in [3,8,9] applies to elliptic problems in curvilinear polygons with mixed Neumann and Dirichlet boundary conditions provided that the Babuska-Brezzi inf-sup conditions are satisfied. We establish basic stability estimates for a no

  8. High Order Finite Difference Methods, Multidimensional Linear Problems and Curvilinear Coordinates

    Science.gov (United States)

    Nordstrom, Jan; Carpenter, Mark H.

    1999-01-01

    Boundary and interface conditions are derived for high order finite difference methods applied to multidimensional linear problems in curvilinear coordinates. The boundary and interface conditions lead to conservative schemes and strict and strong stability provided that certain metric conditions are met.

  9. Linear and Curvilinear Trajectories of Cortical Loss with Advancing Age and Disease Duration in Parkinson's Disease.

    Science.gov (United States)

    Claassen, Daniel O; Dobolyi, David G; Isaacs, David A; Roman, Olivia C; Herb, Joshua; Wylie, Scott A; Neimat, Joseph S; Donahue, Manus J; Hedera, Peter; Zald, David H; Landman, Bennett A; Bowman, Aaron B; Dawant, Benoit M; Rane, Swati

    2016-05-01

    Advancing age and disease duration both contribute to cortical thinning in Parkinson's disease (PD), but the pathological interactions between them are poorly described. This study aims to distinguish patterns of cortical decline determined by advancing age and disease duration in PD. A convenience cohort of 177 consecutive PD patients, identified at the Vanderbilt University Movement Disorders Clinic as part of a clinical evaluation for Deep Brain Stimulation (age: M= 62.0, SD 9.3), completed a standardized clinical assessment, along with structural brain Magnetic Resonance Imaging scan. Age and gender matched controls (n=53) were obtained from the Alzheimer Disease Neuroimaging Initiative and Progressive Parkinson's Marker Initiative (age: M= 63.4, SD 12.2). Estimated changes in cortical thickness were modeled with advancing age, disease duration, and their interaction. The best-fitting model, linear or curvilinear (2(nd), or 3(rd) order natural spline), was defined using the minimum Akaike Information Criterion, and illustrated on a 3-dimensional brain. Three curvilinear patterns of cortical thinning were identified: early decline, late decline, and early-stable-late. In contrast to healthy controls, the best-fit model for age related changes in PD is curvilinear (early decline), particularly in frontal and precuneus regions. With advancing disease duration, a curvilinear model depicts accelerating decline in the occipital cortex. A significant interaction between advancing age and disease duration is evident in frontal, motor, and posterior parietal areas. Study results support the hypothesis that advancing age and disease duration differentially affect regional cortical thickness and display regional dependent linear and curvilinear patterns of thinning. PMID:27330836

  10. Numerical Calculation of 3—D TUrbulent Flow in Curvilinear Coordinate Systems with Nostaggered Grids

    Institute of Scientific and Technical Information of China (English)

    ZhangJingzhou; LiLiguo; 等

    1996-01-01

    The nonstaggered grids are adopted in this paper for solving the governing equations of flows in the curvilinear coordinate systems.The present paper demonstrates the basic reason and corresponding eliminating method for the pressure oscillation,and deduces the corrected expressions for the curvilinear velocity components in which and additional term representing the difference between the 1-δ and 2-δ difference values for the pressure gradient appears.Thus if an oscillatory pressure filed were arisen,the magnitude of this term would be large and would act to remove the oscillation;whereas for nonoscillatory field the magnitude of this term remains small.As examination for the numerical method 3-D turbulent flow in a square duct with 90° bend and 3-D turbulent mixing low in a lobed-mixer were calculatied respectively.The numerical results are satisfactory.

  11. A general nuclear motion Hamiltonian and non-internal curvilinear coordinates.

    Science.gov (United States)

    Strobusch, D; Scheurer, Ch

    2013-03-01

    An exact Hamiltonian for nuclear motions in general curvilinear coordinates is derived. It is demonstrated how this Hamiltonian transforms into well-established expressions, such as the Wilson Howard Hamiltonian or the Meyer Günthard Hamiltonian, if the general coordinates are restricted to be rectilinear or internal. Furthermore, a compact expression for the Hamiltonian expressed in non-internal curvilinear coordinates is provided, which makes this coordinate class available for applications in a simple way, since only the Jacobian matrix with respect to the rotating frame coordinates must be calculated. An example, employing a water model potential, exemplifies how different coordinate systems from all three coordinate classes (rectilinear, internal, and non-internal) lead to vibrational spectra, which are in excellent agreement. Thereby, the applicability of the general Hamiltonian is demonstrated and also its correctness is confirmed.

  12. The effect of culture on the curvilinear relationship between performance and turnover.

    Science.gov (United States)

    Sturman, Michael C; Shao, Lian; Katz, Jan H

    2012-01-01

    Although researchers have theorized that there exists a curvilinear relationship between job performance and voluntary turnover, their research has been tested in the United States or culturally similar Switzerland. Through a study of the performance-turnover relationship from a multinational service-oriented organization in 24 countries, we demonstrate that the general relationship between performance and turnover is similar across countries but the details of that relationship change across countries. Using 4 cultural dimensions--in-group collectivism, power distance, uncertainty avoidance, and performance orientation--we find that cultural factors alter the overall probability of voluntary turnover and influence the degree of curvilinearity in the performance-turnover relationship. Our findings have implications for research on the performance-turnover relationship, turnover research, and practice.

  13. 'Perfectly' curvilinear profiles for binding as determined by ITC may in fact be multiphasic

    CERN Document Server

    Nissen, Per

    2016-01-01

    In a structural analysis of the proteasome activator PafE in Mycobacterium tuberculosis, the binding of the activator or shorter constructs to the 20S proteasome core particle (20S CP) or derivatives was measured by isothermal titration calorimetry (Bai et al. Proc Natl Acad Sci USA 113: E1983-E1992. 2016). The data were fitted by the authors by nonlinear least squares to give curvilinear profiles that, at least in part, appear to fit the data very well. However, reanalysis of the data shows that the profiles are much better (P < 0.001) represented as multiphasic, i.e. by a series of straight lines separated by discontinuous transitions, often in the form jumps, than by the conventional curvilinear profiles.

  14. Too much of a good thing: curvilinear relationships between personality traits and job performance.

    Science.gov (United States)

    Le, Huy; Oh, In-Sue; Robbins, Steven B; Ilies, Remus; Holland, Ed; Westrick, Paul

    2011-01-01

    The relationships between personality traits and performance are often assumed to be linear. This assumption has been challenged conceptually and empirically, but results to date have been inconclusive. In the current study, we took a theory-driven approach in systematically addressing this issue. Results based on two different samples generally supported our expectations of the curvilinear relationships between personality traits, including Conscientiousness and Emotional Stability, and job performance dimensions, including task performance, organizational citizenship behavior, and counterproductive work behaviors. We also hypothesized and found that job complexity moderated the curvilinear personality–performance relationships such that the inflection points after which the relationships disappear were lower for low-complexity jobs than they were for high-complexity jobs. This finding suggests that high levels of the two personality traits examined are more beneficial for performance in high- than low-complexity jobs. We conclude by discussing the implications of these findings for the use of personality in personnel selection. PMID:20939656

  15. MATHEMATICAL MODEL FOR 2-D TIDAL FLOW AND WATER QUALITY WITH ORTHOGONAL CURVILINEAR COORDINATES

    Institute of Scientific and Technical Information of China (English)

    Liu Yu-ling; Wei Wen-li; Shen Yong-ming

    2003-01-01

    This paper presents a numerical method forsimulating the 2-D tidal flow and water quality with the or-thogonal curvilinear coordinates. In order to overcome thecomputational difficulties in natural rivers, such as the com-plicated boundary figures, the great disparity between lengthand width of computational domain, etc. , orthogonal bounda-ry-fitted grid was used. The irregular domain in physical planewas transformed into a rectangular domain in a transformedplane, and the depth-averaged momentum equations and massequation were given and discretized based on the alternatingdirection implicit finite difference scheme in curvilinear coordi-nates. The application of the presented method was illustratedby an example of analyzing the Yangtze River in the vicinity ofNanjing city. A fair agreement between the measured data andcomputed results demonstrates the validity of the developedmethod.

  16. Modeling of a Curvilinear Planar Crack with a Curvature-Dependent Surface Tension

    KAUST Repository

    Zemlyanova, A. Y.

    2012-01-01

    An approach to modeling fracture incorporating interfacial mechanics is applied to the example of a curvilinear plane strain crack. The classical Neumann boundary condition is augmented with curvature-dependent surface tension. It is shown that the considered model eliminates the integrable crack-tip stress and strain singularities of order 1/2 present in the classical linear fracture mechanics solutions, and also leads to the sharp crack opening that is consistent with empirical observations. Unlike for the case of a straight crack, for a general curvilinear crack some components of the stresses and the derivatives of the displacements may still possess weaker singularities of a logarithmic type. Generalizations of the present study that lead to complete removal of all crack-tip singularities, including logarithmic, are the subject of a future paper. © 2012 Society for Industrial and Applied Mathematics.

  17. Nonlinear dimension reduction and clustering by Minimum Curvilinearity unfold neuropathic pain and tissue embryological classes

    KAUST Repository

    Cannistraci, Carlo

    2010-09-01

    Motivation: Nonlinear small datasets, which are characterized by low numbers of samples and very high numbers of measures, occur frequently in computational biology, and pose problems in their investigation. Unsupervised hybrid-two-phase (H2P) procedures-specifically dimension reduction (DR), coupled with clustering-provide valuable assistance, not only for unsupervised data classification, but also for visualization of the patterns hidden in high-dimensional feature space. Methods: \\'Minimum Curvilinearity\\' (MC) is a principle that-for small datasets-suggests the approximation of curvilinear sample distances in the feature space by pair-wise distances over their minimum spanning tree (MST), and thus avoids the introduction of any tuning parameter. MC is used to design two novel forms of nonlinear machine learning (NML): Minimum Curvilinear embedding (MCE) for DR, and Minimum Curvilinear affinity propagation (MCAP) for clustering. Results: Compared with several other unsupervised and supervised algorithms, MCE and MCAP, whether individually or combined in H2P, overcome the limits of classical approaches. High performance was attained in the visualization and classification of: (i) pain patients (proteomic measurements) in peripheral neuropathy; (ii) human organ tissues (genomic transcription factor measurements) on the basis of their embryological origin. Conclusion: MC provides a valuable framework to estimate nonlinear distances in small datasets. Its extension to large datasets is prefigured for novel NMLs. Classification of neuropathic pain by proteomic profiles offers new insights for future molecular and systems biology characterization of pain. Improvements in tissue embryological classification refine results obtained in an earlier study, and suggest a possible reinterpretation of skin attribution as mesodermal. © The Author(s) 2010. Published by Oxford University Press.

  18. A New View on Geometry Optimization: the Quasi-Independent Curvilinear Coordinate Approximation

    OpenAIRE

    Németh, Károly; Challacombe, Matt

    2004-01-01

    This article presents a new and efficient alternative to well established algorithms for molecular geometry optimization. The new approach exploits the approximate decoupling of molecular energetics in a curvilinear internal coordinate system, allowing separation of the 3N-dimensional optimization problem into an O(N) set of quasi-independent one-dimensional problems. Each uncoupled optimization is developed by a weighted least squares fit of energy gradients in the internal coordinate system...

  19. Solving Electromagnetic Scattering and Radiation by FMM with Curvilinear RWG Basis

    Institute of Scientific and Technical Information of China (English)

    HUJun; NIEZaiping; GONGXiaodong

    2003-01-01

    In this paper, fast multipole method (FMM) with curvilinear RWG basis is used to realize fast,accurate solution of electromagnetic scattering and radia-tion from 3-D conducting object. This method needs much less unknowns than traditional RWG basis and conformal rooftop basis, so is especially appropriate for efficient so-lution of scattering and radiation from target with large electrical sizes. Some typical numerical results are shown to demonstrate the validity and efficiency of the presentmethod.

  20. Formulations of the 3+1 evolution equations in curvilinear coordinates

    OpenAIRE

    Alcubierre, Miguel; Mendez, Martha D.

    2010-01-01

    Following Brown, in this paper we give an overview of how to modify standard hyperbolic formulations of the 3+1 evolution equations of General Relativity in such a way that all auxiliary quantities are true tensors, thus allowing for these formulations to be used with curvilinear sets of coordinates such as spherical or cylindrical coordinates. After considering the general case for both the Nagy-Ortiz-Reula (NOR) and the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulations, we specialize t...

  1. Modeling of a curvilinear planar crack with a curvature-dependent surface tension

    CERN Document Server

    Zemlyanova, A Y

    2011-01-01

    In this paper, an approach to modeling fracture incorporating interfacial mechanics is applied to the example of a curvilinear plane strain crack. The classical Neumann boundary condition is augmented with curvature-dependent surface tension. It is shown that the considered model eliminates the integrable crack-tip stress and strain singularities of order 1/2 present in the classical linear fracture mechanics solutions, and also leads to the sharp crack opening that is consistent with empirical observations.

  2. "All or nothing": attachment avoidance and the curvilinear effects of partner support.

    Science.gov (United States)

    Girme, Yuthika U; Overall, Nickola C; Simpson, Jeffry A; Fletcher, Garth J O

    2015-03-01

    People high in attachment avoidance typically respond more negatively to partner support, but some research suggests they can be calmed by high levels of practical support. In the present research, we attempted to reconcile these inconsistencies by modeling curvilinear associations between romantic partners' support and support recipients' outcomes and testing whether these curvilinear associations were moderated by recipients' degree of attachment avoidance. We examined the effect of partner support during support-relevant discussions (Studies 1-3) and in daily life (Study 4) on support recipients' distress (Studies 1-4), self-efficacy (Studies 2 and 3), perceived partner control/criticism (Studies 2 and 4), and distancing from the partner (Study 4). The results and a meta-analysis across all four studies (N = 298 couples) demonstrated that the curvilinear effect of practical support on recipients' outcomes was moderated by attachment avoidance. Highly avoidant recipients exhibited more negative responses as their partner provided them low-to-moderate levels of practical support, including increasing distress, perceived partner control/criticism and distancing, and decreasing self-efficacy. However, as partners' practical support shifted from moderate to high levels, highly avoidant recipients experienced more positive outcomes, including decreasing distress, perceived partner control/criticism and distancing, and increasing self-efficacy. Less avoidant individuals were resilient and experienced better outcomes regardless of the level of partner support they received. These results demonstrate the utility of curvilinear models in reconciling the costs and benefits of support, and indicate that high levels of practical support can overcome the defenses of highly avoidant individuals by offering undeniable evidence of the partner's availability. PMID:25751717

  3. Uncovering curvilinear relationships between conscientiousness and job performance: how theoretically appropriate measurement makes an empirical difference.

    Science.gov (United States)

    Carter, Nathan T; Dalal, Dev K; Boyce, Anthony S; O'Connell, Matthew S; Kung, Mei-Chuan; Delgado, Kristin M

    2014-07-01

    The personality trait of conscientiousness has seen considerable attention from applied psychologists due to its efficacy for predicting job performance across performance dimensions and occupations. However, recent theoretical and empirical developments have questioned the assumption that more conscientiousness always results in better job performance, suggesting a curvilinear link between the 2. Despite these developments, the results of studies directly testing the idea have been mixed. Here, we propose this link has been obscured by another pervasive assumption known as the dominance model of measurement: that higher scores on traditional personality measures always indicate higher levels of conscientiousness. Recent research suggests dominance models show inferior fit to personality test scores as compared to ideal point models that allow for curvilinear relationships between traits and scores. Using data from 2 different samples of job incumbents, we show the rank-order changes that result from using an ideal point model expose a curvilinear link between conscientiousness and job performance 100% of the time, whereas results using dominance models show mixed results, similar to the current state of the literature. Finally, with an independent cross-validation sample, we show that selection based on predicted performance using ideal point scores results in more favorable objective hiring outcomes. Implications for practice and future research are discussed. PMID:24188394

  4. Distributed Representation of Curvilinear Self-Motion in the Macaque Parietal Cortex

    Directory of Open Access Journals (Sweden)

    Zhixian Cheng

    2016-05-01

    Full Text Available Information about translations and rotations of the body is critical for complex self-motion perception during spatial navigation. However, little is known about the nature and function of their convergence in the cortex. We measured neural activity in multiple areas in the macaque parietal cortex in response to three different types of body motion applied through a motion platform: translation, rotation, and combined stimuli, i.e., curvilinear motion. We found a continuous representation of motion types in each area. In contrast to single-modality cells preferring either translation-only or rotation-only stimuli, convergent cells tend to be optimally tuned to curvilinear motion. A weighted summation model captured the data well, suggesting that translation and rotation signals are integrated subadditively in the cortex. Interestingly, variation in the activity of convergent cells parallels behavioral outputs reported in human psychophysical experiments. We conclude that representation of curvilinear self-motion perception is widely distributed in the primate sensory cortex.

  5. Geometry Optimization of Crystals by the Quasi-Independent Curvilinear Coordinate Approximation

    CERN Document Server

    Németh, K

    2005-01-01

    The quasi-independent curvilinear coordinate approximation (QUICCA) method [K. N\\'emeth and M. Challacombe, J. Chem. Phys. {\\bf 121}, 2877, (2004)] is extended to the optimization of crystal structures. We demonstrate that QUICCA is valid under periodic boundary conditions, enabling simultaneous relaxation of the lattice and atomic coordinates, as illustrated by tight optimization of polyethylene, hexagonal boron-nitride, a (10,0) carbon-nanotube, hexagonal ice, quartz and sulfur at the $\\Gamma$-point RPBE/STO-3G level of theory.

  6. A computer program for generating two-dimensional boundary-fitted orthogonal curvilinear coordinate systems

    Energy Technology Data Exchange (ETDEWEB)

    Barbaro, M. [ENEA, Centro Ricerche `Ezio Clementel`, Bologna (Italy). Dipt. Innovazione

    1997-11-01

    A numerical method is described which generates an orthogonal curvilinear mesh, subject to the constraint that mesh lines are matched to all boundaries of a closed, simply connected two-dimensional region of arbitrary shape. The method is based on the solution, by an iterative finite-difference technique, of an elliptic differential system of equations for the Cartesian coordinates of the orthogonal grid nodes. The interior grid distribution is controlled by a technique which ensures that coordinate lines can be concentrated as desired. Examples of orthogonal meshes inscribed in various geometrical figures are included.

  7. Generation of orthogonal curvilinear grids on the sphere surface based on Laplace-Beltrami equations

    International Nuclear Information System (INIS)

    In this paper, Laplace-Beltrami equations are used to generate orthogonal curvilinear grids on the sphere for ocean models. In addition to overcoming the pole-problem, the grid configuration has quasi-uniform cell-size on the whole sphere. Some quantities such as the grid length along two directions, the angle deviation from orthogonality, the area of the cell to evaluate the quality of the grid, which demonstrate the grid produced is fit to be a model grid on which the finite difference method or finite volume method can be implemented for numerical simulating of global atmosphere and ocean dynamics on large scale

  8. Numerical model of flow and pollutant transportation in non-orthogonal curvilinear coordinates

    Institute of Scientific and Technical Information of China (English)

    WU Xiu-guang; SHEN Yong-ming; ZHENG Yong-hong; YANG Zhi-feng

    2004-01-01

    The planar 2D k-ε double equations' turbulence model was adopted and transformed into non-orthogonalcurvilinear coordinates. The concentration convection-diffusion was introduced to planar 2D SIMPLEC algorithm offlow in non-orthogonal curvilinear coordinates. The numerical model of pollutant transportation in non-orthogonalcurvilinear coordinates was constructed. The model was applied to simulate the flow and pollutant concentrationfields. In the testing concentration field, two optimal operations of contamination discharging both along bank and inthe centerline at the first bend of the meandering channel were adopted. Comparison with available data showed themodel developed was successful, was valuable to engineering application.

  9. CURVILINEAR PATHS AND TRUST REGION METHODS WITH NONMONOTONIC BACK TRACKING TECHNIQUE FOR UNCONSTRAINED OPTIMIZATION

    Institute of Scientific and Technical Information of China (English)

    De-tong Zhu

    2001-01-01

    In this paper we modify type approximate trust region methods via two curvilinear paths for unconstrained optimization. A mixed strategy using both trust region and line search techniques is adopted which switches to back tracking steps when a trial step produced by the trust region subproblem is unacceptable. We give a series of properties of both optimal path and modified gradient path. The global convergence and fast local convergence rate of the proposed algorithms are established under some reasonable conditions. A nonmonotonic criterion is used to speed up the convergence progress in some ill-conditioned cases.

  10. Marker Pen Lithography for Flexible and Curvilinear On-Chip Energy Storage

    KAUST Repository

    Jiang, Qiu

    2015-07-14

    On-chip energy storage using microsupercapacitors can serve the dual role of supplementing batteries for pulse power delivery, and replacement of bulky electrolytic capacitors in ac-line filtering applications. Despite complexity and processing costs, microfabrication techniques are being employed in fabricating a great variety of microsupercapacitor devices. Here, a simple, cost-effective, and versatile strategy is proposed to fabricate flexible and curvilinear microsupercapacitors (MSCs). The protocol involves writing sacrificial ink patterns using commercial marker pens on rigid, flexible, and curvilinear substrates. It is shown that this process can be used in both lift-off and etching modes, and the possibility of multistack design of active materials using simple pen lithography is demonstrated. As a prototype, this method is used to produce conducting polymer MSCs involving both poly(3,4-ethylenedioxythiophene), polyaniline, and metal oxide (MnO2) electrode materials. Typical values of energy density in the range of 5-11 mWh cm-3 at power densities of 1-6 W cm-3 are achieved, which is comparable to thin film batteries and superior to the carbon and metal oxide based microsupercapacitors reported in the literature. The simplicity and broad scope of this innovative strategy can open up new avenues for easy and scalable fabrication of a wide variety of on-chip energy storage devices. © 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim.

  11. Anharmonic Vibrational Treatment Exclusively in Curvilinear Valence Coordinates: The Case of Formamide.

    Science.gov (United States)

    Richter, F; Thaunay, F; Lauvergnat, D; Carbonnière, P

    2015-12-01

    A highly correlated approach using curvilinear valence coordinates is applied to calculate the vibrational fundamentals and some combination modes of the formamide molecule with high accuracy. A series of potential energy surfaces (PESs) has been generated by AGAPES, a program for adaptive generation of adiabatic PESs, at various electronic structure qualities until excellent nonaccidental agreement with the experimentally assigned fundamental transitions was reached at the CCSDT(T)-F12a/aug-cc-pVTZ level of theory using the improved relaxation method of the Heidelberg multiconfiguration time-dependent Hartree (MCTDH) package in connection with an exact expression for the kinetic energy in valence coordinates generated by the TANA program. By comparison of the overtone series ν1-3ν1 to experiment, we demonstrate that the known problems concerning the floppy ν1 wagging motion are solved within this approach. The potential energy coupling as well as the vibrational coupling in curvilinear coordinates is discussed together with the efficiency of this approach.

  12. An Arbitrary Curvilinear Coordinate Method for Particle-In-Cell Modeling

    CERN Document Server

    Fichtl, C A; Cartwright, K L

    2012-01-01

    A new approach to the kinetic simulation of plasmas in complex geometries, based on the Particle-in- Cell (PIC) simulation method, is explored. In the two dimensional (2d) electrostatic version of our method, called the Arbitrary Curvilinear Coordinate PIC (ACC-PIC) method, all essential PIC operations are carried out in 2d on a uniform grid on the unit square logical domain, and mapped to a nonuniform boundary-fitted grid on the physical domain. As the resulting logical grid equations of motion are not separable, we have developed an extension of the semi-implicit Modified Leapfrog (ML) integration technique to preserve the symplectic nature of the logical grid particle mover. A generalized, curvilinear coordinate formulation of Poisson's equations to solve for the electrostatic fields on the uniform logical grid is also developed. By our formulation, we compute the plasma charge density on the logical grid based on the particles' positions on the logical domain. That is, the plasma particles are weighted to...

  13. Development of a computational environment for the General Curvilinear Ocean Model

    International Nuclear Information System (INIS)

    The General Curvilinear Ocean Model (GCOM) differs significantly from the traditional approach, where the use of Cartesian coordinates forces the model to simulate terrain as a series of steps. GCOM utilizes a full three-dimensional curvilinear transformation, which has been shown to have greater accuracy than similar models and to achieve results more efficiently. The GCOM model has been validated for several types of water bodies, different coastlines and bottom shapes, including the Alarcon Seamount, Southern California Coastal Region, the Valencia Lake in Venezuela, and more recently the Monterey Bay. In this paper, enhancements to the GCOM model and an overview of the computational environment (GCOM-CE) are presented. Model improvements include migration from F77 to F90; approach to a component design; and initial steps towards parallelization of the model. Through the use of the component design, new models are being incorporated including biogeochemical, pollution, and sediment transport. The computational environment is designed to allow various client interactions via secure Web applications (portal, Web services, and Web 2.0 gadgets). Features include building jobs, managing and interacting with long running jobs; managing input and output files; quick visualization of results; publishing of Web services to be used by other systems such as larger climate models. The CE is based mainly on Python tools including a grid-enabled Pylons Web application Framework for Web services, pyWSRF (python-Web Services-Resource Framework), pyGlobus based web services, SciPy, and Google code tools.

  14. Modelling the determinants of 2000 m rowing ergometer performance: a proportional, curvilinear allometric approach.

    Science.gov (United States)

    Nevill, A M; Allen, S V; Ingham, S A

    2011-02-01

    Previous studies have investigated the determinants of indoor rowing using correlations and linear regression. However, the power demands of ergometer rowing are proportional to the cube of the flywheel's (and boat's) speed. A rower's speed, therefore, should be proportional to the cube root (0.33) of power expended. Hence, the purpose of the present study was to explore the relationship between 2000 m indoor rowing speed and various measures of power of 76 elite rowers using proportional, curvilinear allometric models. The best single predictor of 2000 m rowing ergometer performance was power at VO(2max)(WVO(2max))(0.28), that explained R(2)=95.3% in rowing speed. The model realistically describes the greater increment in power required to improve a rower's performance by the same amount at higher speeds compared with that at slower speeds. Furthermore, the fitted exponent, 0.28 (95% confidence interval 0.226-0.334) encompasses 0.33, supporting the assumption that rowing speed is proportional to the cube root of power expended. Despite an R(2)=95.3%, the initial model was unable to explain "sex" and "weight-class" differences in rowing performances. By incorporating anaerobic as well as aerobic determinants, the resulting curvilinear allometric model was common to all rowers, irrespective of sex and weight class. PMID:19883389

  15. A curvilinear, fully implicit, conservative electromagnetic PIC algorithm in multiple dimensions

    Science.gov (United States)

    Chacón, L.; Chen, G.

    2016-07-01

    We extend a recently proposed fully implicit PIC algorithm for the Vlasov-Darwin model in multiple dimensions (Chen and Chacón (2015) [1]) to curvilinear geometry. As in the Cartesian case, the approach is based on a potential formulation (ϕ, A), and overcomes many difficulties of traditional semi-implicit Darwin PIC algorithms. Conservation theorems for local charge and global energy are derived in curvilinear representation, and then enforced discretely by a careful choice of the discretization of field and particle equations. Additionally, the algorithm conserves canonical-momentum in any ignorable direction, and preserves the Coulomb gauge ∇ ṡ A = 0 exactly. An asymptotically well-posed fluid preconditioner allows efficient use of large cell sizes, which are determined by accuracy considerations, not stability, and can be orders of magnitude larger than required in a standard explicit electromagnetic PIC simulation. We demonstrate the accuracy and efficiency properties of the algorithm with numerical experiments in mapped meshes in 1D-3V and 2D-3V.

  16. Maternal Encouragement to Approach Novelty: A Curvilinear Relation to Change in Anxiety for Inhibited Toddlers.

    Science.gov (United States)

    Kiel, Elizabeth J; Premo, Julie E; Buss, Kristin A

    2016-04-01

    Various parenting behaviors (e.g., protection, intrusiveness, sensitivity) have been shown to impact young children's anxiety development, particularly for temperamentally inhibited children. These behaviors have sometimes predicted both increases and decreases in anxiety in inhibited children, suggesting that linear relations may not adequately model their influence. In the current study, we proposed the dimension of encouragement to approach novelty to characterize parenting behavior ranging from very little encouragement (i.e., protective behavior) to very strong encouragement (i.e., intrusiveness), with gentle encouragement residing in the middle. In a sample of 110 toddlers (48 female, 62 male) and their mothers, the linear and curvilinear effects of this parenting dimension were investigated in relation to change in child separation anxiety and shyness from age 2 to age 3. Inhibited temperament was also investigated as a moderator. Encouragement to approach novelty displayed the hypothesized curvilinear relation to change in separation anxiety, but not shyness, at extreme levels of inhibited temperament. Toddlers increased in separation anxiety when mothers' encouragement resided at either extreme end of the continuum, with lower child anxiety occurring when mothers displayed behavior closer to the middle of the continuum. Implications for the study of parenting outcomes for inhibited toddlers are discussed. PMID:26050798

  17. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    Directory of Open Access Journals (Sweden)

    Shan-Shan Qi

    Full Text Available The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%, compared with the native plants (over 60%. Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

  18. Improvements in a Curvilinear Internal Coordinate Model for the CH Stretching and Bending Vibrations in Trihalomethanes

    Science.gov (United States)

    Kauppi, E.

    1994-10-01

    The interactions between the CH stretching and bending vibrations in CH X3-type symmetric-top molecules have been studied. The previous curvilinear internal coordinate vibrational Hamiltonian (E. Kauppi and L. Halonen, J. Chem. Phys.90, 6980-6992, 1989) has been improved by including contributions arising from the nonlinearity of the redundancy relation between the curvilinear internal coordinates. This affects the anharmonic kinetic energy terms of the pure CH bending Hamiltonian. Vibrational energy levels have been calculated variationally. The model has been applied to data for CHF 3, CHCl 3, CHBr 3, and (CF 3) 3CH. The potential energy parameters have been optimized by a nonlinear least-squares method using vibrational term values as data. In the cases of CHF 3, CHCl 3, and CHBr 3 data for bath 12C and 13C isotopomers have been treated with one set of isotope invariant potential energy parameters. Good fits have been obtained by using five or six adjustable parameters. The values for the quartic bending force constants change considerably from the values obtained by ignoring the nonlinear redundancy contributions.

  19. Numerical Simulation of Wave-Induced Currents Combined with Parabolic Mild-Slope Equation in Curvilinear Coordinates

    Institute of Scientific and Technical Information of China (English)

    CUI Lei; TONG Fei-fei; SHI Feng

    2011-01-01

    Researches on breaking-induced currents by waves are summarized firstly in this paper.Then,a combined numerical model in orthogonal curvilinear coordinates is presented to simulate wave-induced current in areas with curved boundary or irregular coastline.The proposed wave-induced current model includes a nearshore current module established through orthogonal curvilinear transformation form of shallow water equations and a wave module based on the curvilinear parabolic approximation wave equation.The wave module actually serves as the driving force to provide the current module with required radiation stresses.The Crank-Nicolson finite difference scheme and the alternating directions implicit method are used to solve the wave and current module,respectively.The established surf zone currents model is validated by two numerical experiments about longshore currents and rip currents in basins with rip channel and breakwater.The numerical results are compared with the measured data and published numerical results.

  20. Global structure search for molecules on surfaces: Efficient sampling with curvilinear coordinates.

    Science.gov (United States)

    Krautgasser, Konstantin; Panosetti, Chiara; Palagin, Dennis; Reuter, Karsten; Maurer, Reinhard J

    2016-08-28

    Efficient structure search is a major challenge in computational materials science. We present a modification of the basin hopping global geometry optimization approach that uses a curvilinear coordinate system to describe global trial moves. This approach has recently been shown to be efficient in structure determination of clusters [C. Panosetti et al., Nano Lett. 15, 8044-8048 (2015)] and is here extended for its application to covalent, complex molecules and large adsorbates on surfaces. The employed automatically constructed delocalized internal coordinates are similar to molecular vibrations, which enhances the generation of chemically meaningful trial structures. By introducing flexible constraints and local translation and rotation of independent geometrical subunits, we enable the use of this method for molecules adsorbed on surfaces and interfaces. For two test systems, trans-β-ionylideneacetic acid adsorbed on a Au(111) surface and methane adsorbed on a Ag(111) surface, we obtain superior performance of the method compared to standard optimization moves based on Cartesian coordinates.

  1. Global structure search for molecules on surfaces: Efficient sampling with curvilinear coordinates

    Science.gov (United States)

    Krautgasser, Konstantin; Panosetti, Chiara; Palagin, Dennis; Reuter, Karsten; Maurer, Reinhard J.

    2016-08-01

    Efficient structure search is a major challenge in computational materials science. We present a modification of the basin hopping global geometry optimization approach that uses a curvilinear coordinate system to describe global trial moves. This approach has recently been shown to be efficient in structure determination of clusters [C. Panosetti et al., Nano Lett. 15, 8044-8048 (2015)] and is here extended for its application to covalent, complex molecules and large adsorbates on surfaces. The employed automatically constructed delocalized internal coordinates are similar to molecular vibrations, which enhances the generation of chemically meaningful trial structures. By introducing flexible constraints and local translation and rotation of independent geometrical subunits, we enable the use of this method for molecules adsorbed on surfaces and interfaces. For two test systems, trans-β-ionylideneacetic acid adsorbed on a Au(111) surface and methane adsorbed on a Ag(111) surface, we obtain superior performance of the method compared to standard optimization moves based on Cartesian coordinates.

  2. Evidence for a curvilinear relationship between sympathetic nervous system activation and women's physiological sexual arousal.

    Science.gov (United States)

    Lorenz, Tierney Ahrold; Harte, Christopher B; Hamilton, Lisa Dawn; Meston, Cindy M

    2012-01-01

    There is increasing evidence that women's physiological sexual arousal is facilitated by moderate sympathetic nervous system (SNS) activation. Literature also suggests that the level of SNS activation may play a role in the degree to which SNS activity affects sexual arousal. We provide the first empirical examination of a possible curvilinear relationship between SNS activity and women's genital arousal using a direct measure of SNS activation in 52 sexually functional women. The relationship between heart rate variability (HRV), a specific and sensitive marker of SNS activation, and vaginal pulse amplitude (VPA), a measure of genital arousal, was analyzed. Moderate increases in SNS activity were associated with higher genital arousal, while very low or very high SNS activation was associated with lower genital arousal. These findings imply that there is an optimal level of SNS activation for women's physiological sexual arousal. PMID:22092348

  3. Characterizing Curvilinear Features Using the Localized Normal-Score Ensemble Kalman Filter

    Directory of Open Access Journals (Sweden)

    Haiyan Zhou

    2012-01-01

    Full Text Available The localized normal-score ensemble Kalman filter is shown to work for the characterization of non-multi-Gaussian distributed hydraulic conductivities by assimilating state observation data. The influence of type of flow regime, number of observation piezometers, and the prior model structure are evaluated in a synthetic aquifer. Steady-state observation data are not sufficient to identify the conductivity channels. Transient-state data are necessary for a good characterization of the hydraulic conductivity curvilinear patterns. Such characterization is very good with a dense network of observation data, and it deteriorates as the number of observation piezometers decreases. It is also remarkable that, even when the prior model structure is wrong, the localized normal-score ensemble Kalman filter can produce acceptable results for a sufficiently dense observation network.

  4. Finite-difference simulation and visualization of elastodynamics in time-evolving generalized curvilinear coordinates

    Science.gov (United States)

    Kaul, Upender K. (Inventor)

    2009-01-01

    Modeling and simulation of free and forced structural vibrations is essential to an overall structural health monitoring capability. In the various embodiments, a first principles finite-difference approach is adopted in modeling a structural subsystem such as a mechanical gear by solving elastodynamic equations in generalized curvilinear coordinates. Such a capability to generate a dynamic structural response is widely applicable in a variety of structural health monitoring systems. This capability (1) will lead to an understanding of the dynamic behavior of a structural system and hence its improved design, (2) will generate a sufficiently large space of normal and damage solutions that can be used by machine learning algorithms to detect anomalous system behavior and achieve a system design optimization and (3) will lead to an optimal sensor placement strategy, based on the identification of local stress maxima all over the domain.

  5. Loss of lag-response curvilinearity of indices of heart rate variability in congestive heart failure

    Directory of Open Access Journals (Sweden)

    Smith Michael L

    2006-06-01

    Full Text Available Abstract Background Heart rate variability (HRV is known to be impaired in patients with congestive heart failure (CHF. Time-domain analysis of ECG signals traditionally relies heavily on linear indices of an essentially non-linear phenomenon. Poincaré plots are commonly used to study non-linear behavior of physiologic signals. Lagged Poincaré plots incorporate autocovariance information and analysis of Poincaré plots for various lags can provide interesting insights into the autonomic control of the heart. Methods Using Poincaré plot analysis, we assessed whether the relation of the lag between heart beats and HRV is altered in CHF. We studied the influence of lag on estimates of Poincaré plot indices for various lengths of beat sequence in a public domain data set (PhysioNet of 29 subjects with CHF and 54 subjects with normal sinus rhythm. Results A curvilinear association was observed between lag and Poincaré plot indices (SD1, SD2, SDLD and SD1/SD2 ratio in normal subjects even for a small sequence of 50 beats (p value for quadratic term 3 × 10-5, 0.002, 3.5 × 10-5 and 0.0003, respectively. This curvilinearity was lost in patients with CHF even after exploring sequences up to 50,000 beats (p values for quadratic term > 0.5. Conclusion Since lagged Poincaré plots incorporate autocovariance information, these analyses provide insights into the autonomic control of heart rate that is influenced by the non-linearity of the signal. The differences in lag-response in CHF patients and normal subjects exist even in the face of the treatment received by the CHF patients.

  6. Minimum curvilinearity to enhance topological prediction of protein interactions by network embedding

    KAUST Repository

    Cannistraci, Carlo

    2013-06-21

    Motivation: Most functions within the cell emerge thanks to protein-protein interactions (PPIs), yet experimental determination of PPIs is both expensive and time-consuming. PPI networks present significant levels of noise and incompleteness. Predicting interactions using only PPI-network topology (topological prediction) is difficult but essential when prior biological knowledge is absent or unreliable.Methods: Network embedding emphasizes the relations between network proteins embedded in a low-dimensional space, in which protein pairs that are closer to each other represent good candidate interactions. To achieve network denoising, which boosts prediction performance, we first applied minimum curvilinear embedding (MCE), and then adopted shortest path (SP) in the reduced space to assign likelihood scores to candidate interactions. Furthermore, we introduce (i) a new valid variation of MCE, named non-centred MCE (ncMCE); (ii) two automatic strategies for selecting the appropriate embedding dimension; and (iii) two new randomized procedures for evaluating predictions.Results: We compared our method against several unsupervised and supervisedly tuned embedding approaches and node neighbourhood techniques. Despite its computational simplicity, ncMCE-SP was the overall leader, outperforming the current methods in topological link prediction.Conclusion: Minimum curvilinearity is a valuable non-linear framework that we successfully applied to the embedding of protein networks for the unsupervised prediction of novel PPIs. The rationale for our approach is that biological and evolutionary information is imprinted in the non-linear patterns hidden behind the protein network topology, and can be exploited for predicting new protein links. The predicted PPIs represent good candidates for testing in high-throughput experiments or for exploitation in systems biology tools such as those used for network-based inference and prediction of disease-related functional modules. The

  7. Application of effective potential to investigation of two-dimensional lenses-mirror electrostatic systems with curvilinear axial trajectories

    CERN Document Server

    Bimurzaev, S B

    2002-01-01

    Movement equations of two-dimensional electron mirrors with curvilinear axial trajectory have been reduced to form similar for such mirrors with rectilinear axial trajectory by introduction of effective potentials. On the basis of this analogy the general expressions to within sizes of the second order trifle, describing time-of-flight and equation of a trajectory in an average plane in two-dimensional electronic mirrors with curvilinear by an axial trajectory are received. The space and time-of-flight focusing conditions and also conditions of elimination of separate kind aberration are determined. By numerical accounts the condition stigmatic focusing elimination spherical aberration of the second order in two and three-electrode mirror electrostatic power analyser are found which electrodes serve pairs of parallel plates divided by direct cracks. The time-of-flight focusing condition up to the second order inclusive for a three-electrode flat mirror are found also. (author)

  8. Orthogonal invariant sets of the diffusion tensor and the development of a curvilinear set suitable for low-anisotropy tissues

    CERN Document Server

    Damion, Robin A; Ingham, Eileen; Jin, Zhongmin; Ries, Michael E

    2014-01-01

    We develop a curvilinear invariant set of the diffusion tensor which may be applied to Diffusion Tensor Imaging measurements on tissues and porous media. This new set is an alternative to the more common invariants such as fractional anisotropy and the diffusion mode. The alternative invariant set possesses a different structure to the other known invariant sets; the second and third members of the curvilinear set measure the degree of orthotropy and oblateness/prolateness, respectively. The proposed advantage of these invariants is that they may work well in situations of low diffusion anisotropy and isotropy, as is often observed in tissues such as cartilage. We also explore the other orthogonal invariant sets in terms of their geometry in relation to eigenvalue space; a cylindrical set, a spherical set (including fractional anisotropy and the mode), and a log-Euclidean set. These three sets have a common structure. The first invariant measures the magnitude of the diffusion, the second and third invariants...

  9. Calculation of fluid flows with staggered and nonstaggered curvilinear nonorthogonal grids. I - The theory. II - A comparison

    Science.gov (United States)

    Melaaen, M. C.

    1992-02-01

    Tensor calculus is presently employed to furnish both necessary coordinate and velocity transformations in the present use of two different finite-volume methods for discretization of conservation equations in 3D curvilinear nonorthogonal coordinates. While one method is based on the nonstaggered grid arrangement and employs Cartesian velocity components as dependent variables in the momentum equations, the other combines a staggered grid arrangement with physical covariant velocity projections in a locally fixed coordinate system. In the second part of this work, a comparative evaluation of the two methods indicates that while results of comparable accuracy are achieved after a similar number of iterations, the staggered method may be recommended for curvilinear nonorthogonal coordinate problems due to its reduced memory and computational requirements.

  10. An overset curvilinear/immersed boundary framework for high resolution simulations of wind and hydrokinetic turbine flows

    Science.gov (United States)

    Borazjani, Iman; Behara, Suresh; Natarajan, Ganesh; Sotiropoulos, Fotis

    2009-11-01

    We generalize the curvilinear/immersed boundary method to incorporate overset grids to enable the simulation of more complicated geometries and increase grid resolution locally near complex immersed boundary. The new method has been applied to carry out high resolution simulations of wind and hydrokinetic turbine rotors. An interior fine mesh contains the rotor blades and is embedded within a coarser background mesh. The rotor blades can be treated either as immersed boundaries or using curvilinear, boundary-conforming overset grids. The numerical methodology has been generalized to include both inertial and non-inertial frame formulations. The method is validated by applying it to simulate the flow for the NREL wind turbine rotor for various turbine operating points. Inviscid, unsteady RANS and LES simulations are carried out and compared with experimental data. Preliminary results will also be presented for the hydrokinetic turbine rotor installed at the Roosevelt Island Tidal Energy project in New York City.

  11. Bound-Preserving Discontinuous Galerkin Methods for Conservative Phase Space Advection in Curvilinear Coordinates

    CERN Document Server

    Endeve, Eirik; Xing, Yulong; Mezzacappa, Anthony

    2014-01-01

    We extend the positivity-preserving method of Zhang & Shu (2010, JCP, 229, 3091-3120) to simulate the advection of neutral particles in phase space using curvilinear coordinates. The ability to utilize these coordinates is important for non-equilibrium transport problems in general relativity and also in science and engineering applications with specific geometries. The method achieves high-order accuracy using Discontinuous Galerkin (DG) discretization of phase space and strong stability-preserving, Runge-Kutta (SSP-RK) time integration. Special care in taken to ensure that the method preserves strict bounds for the phase space distribution function $f$; i.e., $f\\in[0,1]$. The combination of suitable CFL conditions and the use of the high-order limiter proposed in Zhang & Shu (2010) is sufficient to ensure positivity of the distribution function. However, to ensure that the distribution function satisfies the upper bound, the discretization must, in addition, preserve the divergence-free property of ...

  12. Hermitian spin-orbit Hamiltonians on a surface in orthogonal curvilinear coordinates: A new practical approach

    Science.gov (United States)

    Shikakhwa, M. S.; Chair, N.

    2016-05-01

    The Hermitian Hamiltonian of a spin one-half particle with spin-orbit coupling (SOC) confined to a surface that is embedded in a three-dimensional space spanned by a general Orthogonal Curvilinear Coordinate (OCC) is constructed. A gauge field formalism, where the SOC is expressed as a non-Abelian SU (2) gauge field is used. A new practical approach, based on the physical argument that upon confining the particle to the surface by a potential, then it is the physical Hermitian momentum operator transverse to the surface, rather than just the derivative with respect to the transverse coordinate that should be dropped from the Hamiltonian. Doing so, it is shown that the Hermitian Hamiltonian for SOC is obtained with the geometric potential and the geometric kinetic energy terms emerging naturally. The geometric potential is shown to represent a coupling between the transverse component of the gauge field and the mean curvature of the surface that replaces the coupling between the transverse momentum and the gauge field. The most general Hermitian Hamiltonian with linear SOC on a general surface embedded in any 3D OCC system is reported. Explicit plug-and-play formulae for this Hamiltonian on the surfaces of a cylinder, a sphere and a torus are given. The formalism is applied to the Rashba SOC in three dimensions (3D RSOC) and the explicit expressions for the surface Hamiltonians on these three geometries are worked out.

  13. Micro-Grooving and Micro-Threading Tools for Fabricating Curvilinear Features

    Energy Technology Data Exchange (ETDEWEB)

    ADAMS,DAVID P.; VASILE,MICHAEL J.; KRISHNAN,A.S.M.

    2000-07-24

    This paper presents techniques for fabricating microscopic, curvilinear features in a variety of workpiece materials. Micro-grooving and micro-threading tools having cutting widths as small as 13 {micro}m are made by focused ion beam sputtering and used for ultra-precision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide to create a number of critically aligned facets. Sputtering produces rake facets of desired angle and cutting edges having radii of curvature equal to 0.4 {micro}m. Clearance for minimizing frictional drag of a tool results from a particular ion beam/target geometry that accounts for the sputter yield dependence on incidence angle. It is believed that geometrically specific cutting tools of this dimension have not been made previously. Numerically controlled, ultra-precision machining with micro-grooving tools results in a close match between tool width and feature size. Microtools are used to machine 13 {micro}m wide, 4 {micro}m deep, helical grooves in polymethyl methacrylate and 6061 Al cylindrical workplaces. Micro-grooving tools are also used to fabricate sinusoidal cross-section features in planar metal samples.

  14. Hamiltonian for a particle in a magnetic field on a curved surface in orthogonal curvilinear coordinates

    Science.gov (United States)

    Shikakhwa, M. S.; Chair, N.

    2016-08-01

    The Schrödinger Hamiltonian of a spin-less particle as well as the Pauli Hamiltonian with spin-orbit coupling included of a spin one-half particle in electromagnetic fields that are confined to a curved surface embedded in a three-dimensional space spanned by a general Orthogonal Curvilinear Coordinate are constructed. A new approach, based on the physical argument that upon squeezing the particle to the surface by a potential, then it is the physical gauge-covariant kinematical momentum operator (velocity operator) transverse to the surface that should be dropped from the Hamiltonian(s). In both cases, the resulting Hermitian gauge-invariant Hamiltonian on the surface is free from any reference to the component of the vector potential transverse to the surface, and the approach is completely gauge-independent. In particular, for the Pauli Hamiltonian these results are obtained exactly without any further assumptions or approximations. Explicit covariant plug-and-play formulae for the Schrödinger Hamiltonians on the surfaces of a cylinder, a sphere and a torus are derived.

  15. Numerical study of elastic turbulence in a 3D curvilinear micro-channel

    Science.gov (United States)

    Zhang, Hongna; Kunugi, Tomoaki; Li, Fengchen

    2012-11-01

    Elastic turbulence is an intriguing phenomenon of viscoelastic fluid flow, and dominated by the strong nonlinear elasticity due to the existence of flexible microstructures. It implies the possibility to generate a turbulent state (so-called an elastic turbulence) in the micro-scale devices by introducing the viscoelastic fluids, which could significantly enhance the mixing efficiency therein. Several experiments have been carried out to study its characteristics and underlying physics. However, the difficulty in measuring the flow information and behaviors of the microstructures, especially in the cross section normal to the mean flow direction, limits our current understanding and controlling. In the present study, the nondimensionalization method in which the characteristic velocity is defined as the ratio of the solution viscosity to the width of the channel was adopted to simulate the elastic turbulence in the micro-scale devices. And the elastic turbulent flow was obtained numerically in the 3D curvilinear micro-channel. Therein, the characteristics of the velocity field and polymer's behavior are discussed. Moreover, the energy transfer between the kinetic energy and the polymer's elastic energy is also investigated to understand its physical mechanism. Supported by the Japan Society for the Promotion of Science research fellowship and the Ministry of Education, Culture, Sports, Science and Technology via `Energy Science in the Age of Global Warming' of Global Center of Excellence (G-COE) program (J-051).

  16. Stability Estimates for ℎ- Spectral Element Methods for General Elliptic Problems on Curvilinear Domains

    Indian Academy of Sciences (India)

    Pravir Dutt; Satyendra Tomar

    2003-11-01

    In this paper we show that the ℎ- spectral element method developed in [3,8,9] applies to elliptic problems in curvilinear polygons with mixed Neumann and Dirichlet boundary conditions provided that the Babuska–Brezzi inf-sup conditions are satisfied. We establish basic stability estimates for a non-conforming ℎ- spectral element method which allows for simultaneous mesh refinement and variable polynomial degree. The spectral element functions are non-conforming if the boundary conditions are Dirichlet. For problems with mixed boundary conditions they are continuous only at the vertices of the elements. We obtain a stability estimate when the spectral element functions vanish at the vertices of the elements, which is needed for parallelizing the numerical scheme. Finally, we indicate how the mesh refinement strategy and choice of polynomial degree depends on the regularity of the coefficients of the differential operator, smoothness of the sides of the polygon and the regularity of the data to obtain the maximum accuracy achievable.

  17. 3D Numerical Simulation of Overbank Flow in Non-Orthogonal Curvilinear Coordinates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-liang; SHEN Yong-ming; WU Xiu-guang

    2005-01-01

    The velocity field in meandering compound channels with overbank flow is highly three dimensional. To date, its features have been investigated experimentally and little research has been undertaken to investigate the feasibility of reproducing these velocity fields with computer models. If computer modeling were to prove successful in this context, it could become a useful prediction technique and research tool to enhance our understanding of natural river dynamics. A 3-D k-ε turbulence hydrodynamic model in curvilinear coordinates is established to simulate the overbank flow. The body-fitted coordinate is adopted in the horizontal plane, the part grid is adopted in the vertical direction, and the wall-function method is employed to simulate the bed resistance. The model is applied to the simulation of the meandering channel with straight flood plain banks, and the main velocities and secondary velocities for both the longitudinal and cross sections are presented. Comparison and analysis show that the results of simulation are fit to reflect the results of experiment. These results show the application value of the model to 3D overbank flow.

  18. Targeted Victimization: Exploring Linear and Curvilinear Associations Between Social Network Prestige and Victimization.

    Science.gov (United States)

    Andrews, Naomi C Z; Hanish, Laura D; Updegraff, Kimberly A; Martin, Carol Lynn; Santos, Carlos E

    2016-09-01

    Are early adolescent victims of peer-directed aggression youth who hold prominent positions in the social hierarchy or those who are socially marginalized? The present study tackles this question by testing for linear and curvilinear relationships between social network prestige and physical and relational forms of peer victimization for boys and girls. Participants were 952 middle schoolers (age range = 10-14 years; 49.9 % girls; 44 % Latino). Participants nominated victims and friends; friendship nominations were used to calculate social network prestige. Both hypotheses received support, with variation by gender. Girls high in social network prestige were highly victimized. For boys, those both high and low in social network prestige were highly victimized, whereas those at mid-levels of social network prestige were low in victimization. The findings are discussed in relation to a social dominance model of peer-directed aggression, and the practical implications are discussed in relation to protecting youth who are frequent targets of peer victimization. PMID:26920566

  19. The influence of time management skill on the curvilinear relationship between organizational citizenship behavior and task performance.

    Science.gov (United States)

    Rapp, Adam A; Bachrach, Daniel G; Rapp, Tammy L

    2013-07-01

    In this research we integrate resource allocation and social exchange perspectives to build and test theory focusing on the moderating role of time management skill in the nonmonotonic relationship between organizational citizenship behavior (OCB) and task performance. Results from matching survey data collected from 212 employees and 41 supervisors and from task performance metrics collected several months later indicate that the curvilinear association between OCB and task performance is significantly moderated by employees' time management skill. Implications for theory and practice are discussed.

  20. A transformed coordinates shallow water model in boundary-fitted curvilinear grids for the head Bay of Bengal

    International Nuclear Information System (INIS)

    The Bay of Bengal is surrounded by the coasts from all sides except in the south where there is open sea. The coasts are curvilinear in nature and the bending is very high along the coast of Bangladesh. Moreover, there are many small and big islands in the offshore region of the Bangladesh coast. In order to incorporate the island boundaries and the coastlines properly in the numerical scheme it is necessary to consider a very fine grid resolution along the coastal belts, whereas this is unnecessary away from the coasts. Consideration of very fine resolution involves, unnecessarily, more memory and more CPU time in the solution process and invites problem of numerical instability. In hydrodynamic models for coastal seas, bays, and estuaries the use of boundary-fitted curvilinear grids not only makes the model grids fit to the coastline, but also make the finite difference scheme simple and more accurate. In this study we use the boundary-fitted curvilinear grids where the complete boundary of the analysis area is represented by four curves and they are defined by four functions. Based on them, the four boundaries of each island are represented approximately by two generalized functions. Appropriate transformations of independent coordinates are considered so that the curvilinear physical domain transforms to a square one and also each island boundary transforms to a rectangle within this square domain. The vertically integrated shallow water equations are transformed to the new space domain. In the transformed domain, the regular explicit finite difference scheme is used to solve the shallow water equations. The model is applied to compute the water levels due to astronomical tide and surges associated with a few tropical storms that hit the coast of Bangladesh. (author)

  1. Curvilinear Immersed Boundary Method for Simulating Fluid Structure Interaction with Complex 3D Rigid Bodies.

    Science.gov (United States)

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2008-08-10

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries, Journal of Computational Physics 225 (2007) 1782-1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions unconditionally unstable iteration schemes result even when strong coupling FSI is employed. For such cases, however, combining the strong-coupling iteration with under-relaxation in conjunction with the Aitken's acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the FSI

  2. Curvilinear Immersed Boundary Method for Simulating Fluid Structure Interaction with Complex 3D Rigid Bodies.

    Science.gov (United States)

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2008-08-10

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries, Journal of Computational Physics 225 (2007) 1782-1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions unconditionally unstable iteration schemes result even when strong coupling FSI is employed. For such cases, however, combining the strong-coupling iteration with under-relaxation in conjunction with the Aitken's acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the FSI

  3. In vivo visualization of robotically implemented synthetic tracked aperture ultrasound (STRATUS) imaging system using curvilinear array

    Science.gov (United States)

    Zhang, Haichong K.; Aalamifar, Fereshteh; Boctor, Emad M.

    2016-04-01

    Synthetic aperture for ultrasound is a technique utilizing a wide aperture in both transmit and receive to enhance the ultrasound image quality. The limitation of synthetic aperture is the maximum available aperture size limit determined by the physical size of ultrasound probe. We propose Synthetic-Tracked Aperture Ultrasound (STRATUS) imaging system to overcome the limitation by extending the beamforming aperture size through ultrasound probe tracking. With a setup involving a robotic arm, the ultrasound probe is moved using the robotic arm, while the positions on a scanning trajectory are tracked in real-time. Data from each pose are synthesized to construct a high resolution image. In previous studies, we have demonstrated the feasibility through phantom experiments. However, various additional factors such as real-time data collection or motion artifacts should be taken into account when the in vivo target becomes the subject. In this work, we build a robot-based STRATUS imaging system with continuous data collection capability considering the practical implementation. A curvilinear array is used instead of a linear array to benefit from its wider capture angle. We scanned human forearms under two scenarios: one submerged the arm in the water tank under 10 cm depth, and the other directly scanned the arm from the surface. The image contrast improved 5.51 dB, and 9.96 dB for the underwater scan and the direct scan, respectively. The result indicates the practical feasibility of STRATUS imaging system, and the technique can be potentially applied to the wide range of human body.

  4. GCLgrid: A three-dimensional geographical curvilinear grid library for computational seismology

    Science.gov (United States)

    Fan, Chengliang; Pavlis, Gary L.; Tuncay, Kagan

    2006-04-01

    We developed a general library for handling a class of objects we call geographical curvilinear grids (GCLgrids). A GCLgrid is a distorted, uniform grid that is georeferenced. The GCLgrid library is implemented in an object oriented system with methods that relate points in the grid to a geographic reference frame. A simple example is a spherical shell divided along latitude, longitude, and depth, but more elaborate shapes can use the same interface. Scalar and vector fields are derived from the base grid through inheritance. Two algorithms are the core of this library. First, we use the Direction Set method to search for a location in space from a starting point. This algorithm converges reasonably fast if the grid is not extremely distorted. Second, we interpolate the grid using methods known from finite element analysis. A Jacobian matrix for an 8-node cube is computed to transform a distorted cube into a unit one. Shape functions for the standard cube are used to compute interpolation coefficients. Once the interpolation coefficients are computed, we can interpolate n-element vectors almost as quickly as scalar data. We show an application of the library to travel time table calculation at regional distances. Our table interpolator was found to be 10 times faster than one based on the tau-p method and is expected to be several orders of magnitude faster than 3D ray-tracing methods. Travel time interpolation errors are reduced significantly by tabulating delay times relative to a homogenous reference model instead of absolute times. This allows much coarser grids to be used at large scales comparing to one using total time.

  5. A SHALLOW WATER MODEL FOR COMPUTING TSUNAMI ALONG THE WEST COAST OF PENINSULAR MALAYSIA AND THAILAND USING BOUNDARY-FITTED CURVILINEAR GRIDS

    Directory of Open Access Journals (Sweden)

    Md. Fazlul Karim

    2007-01-01

    Full Text Available The west coast of Peninsular Malaysia and Thailand is curvilinear in nature and the bending is especially high along the coast of South Thailand. In hydrodynamic models for coastal seas, bays and estuaries, the use of boundary-fitted curvilinear grids not only makes the model grids fit well with the coastline and bathymetry, but also makes the finite difference scheme simple. In this study, a shallow water model is developed using boundary fitted curvilinear mesh. The west coast of Peninsular Malaysia and Thailand and the western open boundary are represented by two curves, which are defined by two functions. The other two boundaries are considered as straight lines along the open sea. Appropriate transformations of independent coordinates are applied so that the curvilinear physical domain transforms to a rectangular domain and the curvilinear grid system transforms to a rectangular system. The depth averaged shallow water equations and the boundary conditions are transformed to the new space domain and these are solved in the rectangular mesh of the transformed space. The model is applied to compute some aspects of the tsunami associated with the 26 December 2004 Indonesian tsunami along the coastal belts of Penang in Malaysia and Phuket in Thailand. The computed results along the coastal belts are in excellent agreement with the observe data available in the USGS website.

  6. Numerical simulation of four-field extended magnetohydrodynamics in dynamically adaptive curvilinear coordinates via Newton-Krylov-Schwarz

    KAUST Repository

    Yuan, Xuefei

    2012-07-01

    Numerical simulations of the four-field extended magnetohydrodynamics (MHD) equations with hyper-resistivity terms present a difficult challenge because of demanding spatial resolution requirements. A time-dependent sequence of . r-refinement adaptive grids obtained from solving a single Monge-Ampère (MA) equation addresses the high-resolution requirements near the . x-point for numerical simulation of the magnetic reconnection problem. The MHD equations are transformed from Cartesian coordinates to solution-defined curvilinear coordinates. After the application of an implicit scheme to the time-dependent problem, the parallel Newton-Krylov-Schwarz (NKS) algorithm is used to solve the system at each time step. Convergence and accuracy studies show that the curvilinear solution requires less computational effort than a pure Cartesian treatment. This is due both to the more optimal placement of the grid points and to the improved convergence of the implicit solver, nonlinearly and linearly. The latter effect, which is significant (more than an order of magnitude in number of inner linear iterations for equivalent accuracy), does not yet seem to be widely appreciated. © 2012 Elsevier Inc.

  7. Development and application of the discrete ordinate method in orthogonal curvilinear coordinates; Developpement et application de la methode des ordonnees discretes en coordonnees curvilignes orthogonales

    Energy Technology Data Exchange (ETDEWEB)

    Vaillon, R.; Lallemand, M.; Lemonnier, D. [Ecole Nationale Superieure de Mecanique et d`Aerotechnique (ENSMA), 86 - Poitiers (France)

    1996-12-31

    The method of discrete ordinates, which is more and more widely used in radiant heat transfer studies, is mainly developed in Cartesian, (r,z) and (r,{Theta}) cylindrical, and spherical coordinates. In this study, the approach of this method is performed in orthogonal curvilinear coordinates: determination of the radiant heat transfer equation, treatment of the angular redistribution terms, numerical procedure. Some examples of application are described in 2-D geometry defined in curvilinear coordinates along a curve and at the thermal equilibrium. A comparison is made with the discrete ordinates method in association with the finite-volumes method in non structured mesh. (J.S.) 27 refs.

  8. Strong Conservation Form and Grid Generation in Nonsteady Curvilinear Coordinates for Implicit Radiation Hydrodynamics in 2D and 3D

    CERN Document Server

    Höller, Harald

    2012-01-01

    A generalization of implicit conservative numerics to multiple dimensions requires advanced concepts of tensor analysis and differential geometry and hence a more thorough dedication to mathematical fundamentals than maybe expected at first glance. Hence we begin to discuss fundamental mathematics and physics of RHD with special focus on differential geometric consistency and study numerical methods for nonlinear conservation laws to gain a solid definition of the term conservative. The efforts in tensor analysis will be needed when applying Vinokurs theorem to gain the strong conservation form for conservation laws in general curvilinear coordinates. Moreover, it will be required to slightly reformulate the artificial viscosity for such nonlinear coordinates. Astronomical objects are characterized by fast flows and high propagation speeds on the one hand but astronomical length and time scales on the other hand. Implicit numerical schemes are not affected by the Courant Friedrichs Levy condition which limits...

  9. Dispersive Stabilization of Liquid Crystal-in-Water with Acrylamide Copolymer/Surfactant Mixture: Nematic Curvilinear Aligned Phase Composite Film.

    Science.gov (United States)

    Park; Lee

    1999-11-01

    The effect of nonionic surfactant, (H(OCH(2)-CH(2))(8)-OC(6)H(4)-C(9)H(19)), on the dispersion stabilization of liquid crystal (LC)-in-water with acrylamide copolymer containing the related nonylphenyl groups was studied. It was observed that the addition of nonionic surfactant increases the stability of LC dispersions and improves the electrooptical properties of the nematic curvilinear aligned phase (NCAP) composite film. On the basis of the surface tension, reduced viscosity, cloud point, and coalescence time measurements, it was proposed that formation of an integrated structure induced by interactions between hydrophobic groups in the polymer chains is probably important to fabrication of a polymer composite film made of LC and polymer matrix. Copyright 1999 Academic Press.

  10. Curvilinear immersed boundary method for simulating coupled flow and bed morphodynamic interactions due to sediment transport phenomena

    Science.gov (United States)

    Khosronejad, Ali; Kang, Seokkoo; Borazjani, Iman; Sotiropoulos, Fotis

    2011-07-01

    The fluid-structure interaction curvilinear immersed boundary (FSI-CURVIB) numerical method of Borazjani et al. [3] is extended to simulate coupled flow and sediment transport phenomena in turbulent open-channel flows. The mobile channel bed is discretized with an unstructured triangular mesh and is treated as a sharp-interface immersed boundary embedded in a background curvilinear mesh used to discretize the general channel outline. The unsteady Reynolds-averaged Navier-Stokes (URANS) equations closed with the k - ω turbulence model are solved numerically on a hybrid staggered/non-staggered grid using a second-order accurate fractional step method. The bed deformation is calculated by solving the sediment continuity equation in the bed-load layer using an unstructured, finite-volume formulation that is consistent with the CURVIB framework. Both the first-order upwind and the higher-order hybrid GAMMA schemes [12] are implemented to discretize the bed-load flux gradients and their relative accuracy is evaluated through a systematic grid refinement study. The GAMMA scheme is employed in conjunction with a sand-slide algorithm for limiting the bed slope at locations where the material angle of repose condition is violated. The flow and bed deformation equations are coupled using the partitioned loose-coupling FSI-CURVIB approach [3]. The hydrodynamic module of the method is validated by applying it to simulate the flow in an 180° open-channel bend with fixed bed. To demonstrate the ability of the model to simulate bed morphodynamics and evaluate its accuracy, we apply it to calculate turbulent flow through two mobile-bed open channels, with 90° and 135° bends, respectively, for which experimental measurements are available.

  11. The curvilinear relationship between work pressure and momentary task performance: the role of state and trait core self-evaluations.

    Science.gov (United States)

    Hofmans, Joeri; Debusscher, Jonas; Dóci, Edina; Spanouli, Andromachi; De Fruyt, Filip

    2015-01-01

    Whereas several studies have demonstrated that core self-evaluations (CSE)-or one's appraisals about one's own self-worth, capabilities, and competences-relate to job outcomes, less is known about the mechanisms underlying these relationships. In the present study, we address this issue by examining the role of within- and between-person variation in CSE in the relationship between work pressure and task performance. We hypothesized that (a) work pressure relates to task performance in a curvilinear way, (b) state CSE mediates the curvilinear relationship between work pressure and task performance, and (c) the relationship between work pressure and state CSE is moderated by trait CSE. Our hypotheses were tested via a 10-day daily diary study with 55 employees in which trait CSE was measured at baseline, while work pressure, task performance, and state CSE were assessed on a daily basis. Bayesian multilevel path analysis showed that work pressure affects task performance via state CSE, with state CSE increasing as long as the employee feels that (s)he is able to handle the work pressure, while it decreases when the level of work pressure exceeds the employees' coping abilities. Moreover, we found that for people low on trait CSE, the depleting effect of work pressure via state CSE happens for low levels of work pressure, while for people high in trait CSE the depleting effect is located at high levels of work pressure. Together, our findings suggest that the impact of work pressure on task performance is driven by a complex interplay of between- and within-person differences in CSE. PMID:26579053

  12. Automatic differentiation method for numerical construction of the rotational-vibrational Hamiltonian as a power series in the curvilinear internal coordinates using the Eckart frame.

    Science.gov (United States)

    Yachmenev, Andrey; Yurchenko, Sergei N

    2015-07-01

    We present a new numerical method to construct a rotational-vibrational Hamiltonian of a general polyatomic molecule in the Eckart frame as a power series expansion in terms of curvilinear internal coordinates. The expansion of the kinetic energy operator of an arbitrary order is obtained numerically using an automatic differentiation (AD) technique. The method is applicable to molecules of arbitrary size and structure and is flexible for choosing various types of internal coordinates. A new way of solving the Eckart-frame equations for curvilinear coordinates also based on the AD technique is presented. The resulting accuracy of the high-order expansion coefficients for the kinetic energy operator using our numerical technique is comparable to that obtained by symbolic differentiation, with the advantage of being faster and less demanding in memory. Examples for H2CO, NH3, PH3, and CH3Cl molecules demonstrate the advantages of the curvilinear internal coordinates and the Eckart molecular frame for accurate ro-vibrational calculations. Our results show that very high accuracy and quick convergence can be achieved even with moderate expansions if curvilinear coordinates are employed, which is important for applications involving large polyatomic molecules.

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

    Science.gov (United States)

    Han, Kihwan; Jeong, Hoijoon; Choi, Tae Hyun; Kim, Jun Hyung; Son, Daegu

    2015-03-01

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

  14. Long-term job insecurity, job satisfaction and organisational attitudes: Test of Warr’s Curvilinear Hypothesis

    Directory of Open Access Journals (Sweden)

    Hans De Witte

    2005-10-01

    Full Text Available Research suggests that job insecurity is an important work stressor, negatively affecting well-being and organisational attitudes and behaviours. This article concentrates on two often ignored issues in this field. First, the consequences of long-term job insecurity regarding job satisfaction, the evaluation of management and organisational attitudes are analysed. Secondly, Warr’s assumption of curvilinear associations between job insecurity and well-being is tested, and extended to the evaluation of management and organisational attitudes. The hypotheses are tested with data of 769 employees from various branches of a large European multinational company. In total, 15 reliable scales were used to test the hypotheses. The results show that 48,2% of the interviewees had worries about their long-term job security. Separate analyses of variance showed that long-term job insecurity was associated with two thirds of the scales. Long-term job insecurity was associated with lower job satisfaction, lower organisational attitudes and a lower evaluation of supervisors and management. Warr’s assumption of curvilinear associations with job insecurity was not corroborated, however. Suggestions for practice and for future research are discussed. Opsomming Navorsing stel voor dat werksonsekerheid ’n belangrike werk stressor is en dat dit welstand, organisasie gesindhede en gedrag negetief affekteer. Die artikel konsentreer op twee onderwerpe in hierdie veld wat gereeld geignoreer word. Eerstens word die gevolge van langtermyn werksonsekerheid met betrekking tot werkstevredenheid, die evaluering van bestuur en organisasiegesindhede geanaliseer. Tweedens, is Warr se aanames van kromlynige verhoudings tussen werksonsekerheid en welstand getoets, en uitgebrei tot die evaluasie van bestuur en organisasiegesindhede. Die hipotese is getoets met data van 769 werknemers van verskeie takke van ’n groot Europese multinasionale maatskappy. Daar is in totaal 15

  15. Documentation of program AFTBDY to generate coordinate system for 3D after body using body fitted curvilinear coordinates, part 1

    Science.gov (United States)

    Kumar, D.

    1980-01-01

    The computer program AFTBDY generates a body fitted curvilinear coordinate system for a wedge curved after body. This wedge curved after body is being used in an experimental program. The coordinate system generated by AFTBDY is used to solve 3D compressible N.S. equations. The coordinate system in the physical plane is a cartesian x,y,z system, whereas, in the transformed plane a rectangular xi, eta, zeta system is used. The coordinate system generated is such that in the transformed plane coordinate spacing in the xi, eta, zeta direction is constant and equal to unity. The physical plane coordinate lines in the different regions are clustered heavily or sparsely depending on the regions where physical quantities to be solved for by the N.S. equations have high or low gradients. The coordinate distribution in the physical plane is such that x stays constant in eta and zeta direction, whereas, z stays constant in xi and eta direction. The desired distribution in x and z is input to the program. Consequently, only the y-coordinate is solved for by the program AFTBDY.

  16. Apsara: A multi-dimensional unsplit fourth-order explicit Eulerian hydrodynamics code for arbitrary curvilinear grids

    CERN Document Server

    Wongwathanarat, Annop; Müller, Ewald

    2016-01-01

    We present a new fourth-order finite-volume hydrodynamics code named Apsara. The code employs the high-order finite-volume method for mapped coordinates developed by Colella et al. (2011) with extensions for non-linear hyperbolic conservation laws by McCorquodale & Colella (2011) and Guzik et al. (2012). Using the mapped-grid technique Apsara can handle arbitrary structured curvilinear meshes in three spatial dimensions. The code has successfully passed several hydrodynamic test problems including the advection of a Gaussian density profile and a non-linear vortex, as well as the propagation of linear acoustic waves. For these test problems Apsara produces fourth-order accurate results in case of smooth grid mappings. The order of accuracy is reduced to first-order when using the non-smooth circular grid mapping of Calhoun et al. (2008). When applying the high-order method by McCorquodale & Colella (2011) to simulations of low-Mach number flows, e.g. the Gresho vortex and the Taylor-Green vortex, we d...

  17. A three-dimensional k-ε-kp model in curvilinear coordinates for sediment movement and bed evolution

    Institute of Scientific and Technical Information of China (English)

    SHEN YongMing; LIU Cheng

    2009-01-01

    To aim at the substitution of the magnitude and direction of water flow movement near bed for those of bed load transport in solid-liquid two-phase one-fluid model, and to simulate the effect of secondary flow on transverse bed load transport in channel bends and the effect of bed slope on bed load transport in a better way, a three-dimensional k-ε-kp solid-liquid two-phase two-fluid model in curvilinear coordinates is solved numerically with a finite-volume method on an adaptive grid for studying water-sediment movements and bed evolution in a 120° channel bend. Numerical results show that the trajectories of solid-phase deviate from those of liquid-phase in the channel bend, and the deviation increases with the increase of the particle diameters. The calculated bed deformation by the k-ε-kpmodel is in better agreement with measured bed deformation than those by one-fluid model. It is proved that the k-ε-kp model can simulate the effect of secondary flow on lateral bed load transport with the higher accuracy than the one-fluid model.

  18. A three-dimensional k-ε-k_p model in curvilinear coordinates for sediment movement and bed evolution

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To aim at the substitution of the magnitude and direction of water flow movement near bed for those of bed load transport in solid-liquid two-phase one-fluid model, and to simulate the effect of secondary flow on transverse bed load transport in channel bends and the effect of bed slope on bed load trans- port in a better way, a three-dimensional k-ε-kp solid-liquid two-phase two-fluid model in curvilinear coordinates is solved numerically with a finite-volume method on an adaptive grid for studying wa- ter-sediment movements and bed evolution in a 120° channel bend. Numerical results show that the trajectories of solid-phase deviate from those of liquid-phase in the channel bend, and the deviation increases with the increase of the particle diameters. The calculated bed deformation by the k-ε-kp model is in better agreement with measured bed deformation than those by one-fluid model. It is proved that the k-ε-kp model can simulate the effect of secondary flow on lateral bed load transport with the higher accuracy than the one-fluid model.

  19. Analysis of clinical curative effect of minimal invasion surgery for heel pain elderly patients with calcaneal tubercle osteophyte%微创治疗老年跟骨结节骨赘型跟痛症临床疗效分析

    Institute of Scientific and Technical Information of China (English)

    孙建民; 孙良智; 苏保辉; 李忠; 徐晓梅; 刘美秀

    2012-01-01

    [Objective] To discuss the clinical curative effect of minimal invasion surgery for heel pain in elderly patients (age ≥60 years) with calcaneal tubercle osteophyte. [Methods] From July 2000 to July 2010, the surgical methods and clinical curative effect were analyzed in 159 cases ( 173 feet) of heel pain with calcaneal lubercle osteophyle. According to the Maryland scoring system, all the cases were < 50 scores before surgery. Minimally invasive removal of osteophytes, the release of plantar fascia insertion and bursa surgery were operated in 57 feet (minimal invasion group) , while other 47 feet received open surgery ( open group) . [ Results] A total of 93 cases (104 feet) obtained a mean of 19 months follow up. In minimal invasion group, the pain was completely relieved without walking effect in 55 feet. Other 2 feet also improved pain relief significantly, but the pain was residual after severe activity, which can be relieved by rest. In open group, the pain was completely relieved without walking effect in 45 feet. One foot improved pain relief significantly, but the pain was residual after severe activity, which can be relieved by rest. One foot suffered from scarring pain for six months, which disappeared after the softening of the scar. [Conclusion] For the heel pain with calcaneal tubercle osteophyte, it can obtain good clinical curative effect by releasing the plantar fascia insertion and removing the osteophytes and bursa both in minimal invasion surgery and open surgery. Compared with the open surgery, the minimal invasion surgery can be acceptable easily for ihe less invasion and faster recovery.%[目的]探讨老年(年龄≥60岁)跟骨结节骨赘型跟痛症微创治疗的临床疗效.[方法]对2000年7月~2010年7月本院治疗的159例(173足)跟骨结节骨赘型跟痛症老年患者的手术方式及疗效进行分析.根据Maryland 评分患者均<50分,其中82足(微创组)患者接受了微创骨赘切除、跖腱膜止

  20. Quartic canonical force field in curvilinear internal coordinates for XY3 (D3h) molecules. The case of the BH3 molecule.

    Science.gov (United States)

    Ródenas, Consuelo Rosales; Quesada, Juana Vázquez; Torres, Emilio Martínez; González, Juan Jesús López

    2014-06-01

    Using the canonical force field theory, expressions of quadratic, cubic, and quartic canonical force constants are obtained for XY3 (D3h) molecules in curvilinear redundant coordinates, i.e., simple valence internal coordinates (VICs), in terms of force constants in normal coordinates and in independent symmetry coordinates. To carry out this task, it was previously necessary to obtain for the first time the non-linear redundancy relation and the corresponding orthogonal projection onto the pure vibrational manifold for XY3 (D3h) molecules corresponding to a set of seven VICs. As an application, the quartic canonical force field in curvilinear redundant internal coordinates of BH3 is determined from ab initio force fields in normal coordinates calculated at the coupled-cluster singles and doubles level with perturbative treatment of the triples in conjunction with a triple- and quadruple-ζ size basis set. This anharmonic force field so obtained for the borane molecule, and in general for XY3 (D3h) molecules, is uniquely defined (therefore in an unambiguous form) and depending on the same number of parameters, i.e., force constants, when independent coordinates (natural or symmetry) are used in its description.

  1. Stable, high-order SBP-SAT finite difference operators to enable accurate simulation of compressible turbulent flows on curvilinear grids, with application to predicting turbulent jet noise

    Science.gov (United States)

    Byun, Jaeseung; Bodony, Daniel; Pantano, Carlos

    2014-11-01

    Improved order-of-accuracy discretizations often require careful consideration of their numerical stability. We report on new high-order finite difference schemes using Summation-By-Parts (SBP) operators along with the Simultaneous-Approximation-Terms (SAT) boundary condition treatment for first and second-order spatial derivatives with variable coefficients. In particular, we present a highly accurate operator for SBP-SAT-based approximations of second-order derivatives with variable coefficients for Dirichlet and Neumann boundary conditions. These terms are responsible for approximating the physical dissipation of kinetic and thermal energy in a simulation, and contain grid metrics when the grid is curvilinear. Analysis using the Laplace transform method shows that strong stability is ensured with Dirichlet boundary conditions while weaker stability is obtained for Neumann boundary conditions. Furthermore, the benefits of the scheme is shown in the direct numerical simulation (DNS) of a Mach 1.5 compressible turbulent supersonic jet using curvilinear grids and skew-symmetric discretization. Particularly, we show that the improved methods allow minimization of the numerical filter often employed in these simulations and we discuss the qualities of the simulation.

  2. 用自体骨赘填充椎体护架行颈前路椎间融合手术的临床观察%Clinical observation of treatment with Cage filled with osteophyte in anterior cervical disectomy and fusion

    Institute of Scientific and Technical Information of China (English)

    王兴武; 陆建猛; 俞武良; 韦勇力; 方明

    2014-01-01

    目的 观察单纯采用椎体骨赘填充椎体护架(Cage)行颈前路椎体间融合的融合率.方法 2010年1月至2012年7月,对81例行颈前路椎间盘切除减压、融合、钛板内固定手术的患者单纯采集手术间隙椎体前后缘的骨赘填充Cage.男52例,女29例;年龄55~78岁,平均64.1岁,单节段手术46例,双节段35例.术后3个月、6个月和1年复查颈椎X线片和CT观察重建融合效果.结果 术后3个月总融合率为76.5%(62/81),单节段融合率为78.3%(36/46),双节段融合率为74.3%%(26/35).术后6个月总融合率为93.8%(76/81),单节段融合率为95.7%(44/46),双节段融合率为91.4%(32/35).术后1年总融合率为100%(81/81).不同节段手术的融合率差异无统计学意义. 结论 对颈前路单节段或双节段手术,以骨赘填充Cage进行椎体间融合可获得满意的融合率.%Objective To observe the fusion rate by using cage filled with osteophyte in anterior cervical disectomy and fusion.Methods From January 2010 to July 2012,81 patients receiving anterior cervical disectomy and spine fusion underwent treatment with cages containing exclusively autologous osteophyte collected from both anterior and posterior vertebral edges adjacent to the intervertebral space.There were 52 males and 29 females,aged from 55 to 78 years,average 64.1 years in this study.46 patients received one-level fusion,and 35 patients received two-level fusion respectively.Patients were followed up at 3 months,6 months and 1 year after operation.The fusion was evaluated by X-ray film and reconstructive CT.Results The total fusion rate after 3 months of operation was 76.5% (62/81),the one-level and two-level fusion rate were 78.3% (36/46) and 74.3% (26/35),respectively.The total fusion rate after 6 months of operation was 93.8% (76/81),the one-level and two-level fusion rate were 95.7% (44/46) and 91.4% (32/35),respectively.The total fusion rate was 100% (81/81) after 1 year of

  3. Ab initio effective rotational and rovibrational Hamiltonians for non-rigid systems via curvilinear second order vibrational M{\\o}ller-Plesset perturbation theory

    CERN Document Server

    Changala, P Bryan

    2016-01-01

    We present a perturbative method for ab initio calculations of rotational and rovibrational effective Hamiltonians of both rigid and non-rigid molecules. Our approach is based on a curvilinear implementation of second order vibrational M{\\o}ller-Plesset perturbation theory (VMP2) extended to include rotational effects via a second order contact transformation. Though more expensive, this approach is significantly more accurate than standard second order vibrational perturbation theory (VPT2) for systems that are poorly described to zeroth order by rectilinear normal mode harmonic oscillators. We apply this method and demonstrate its accuracy on two molecules: Si$_2$C, a quasilinear triatomic with significant bending anharmonicity, and CH$_3$NO$_2$, which contains a completely unhindered methyl rotor. In addition to these two examples, we discuss several key technical aspects of the method, including an efficient implementation of Eckart and quasi-Eckart frame embedding that does not rely on numerical finite d...

  4. Higher-order in time "quasi-unconditionally stable" ADI solvers for the compressible Navier-Stokes equations in 2D and 3D curvilinear domains

    CERN Document Server

    Bruno, Oscar

    2015-01-01

    This paper introduces alternating-direction implicit (ADI) solvers of higher order of time-accuracy (orders two to six) for the compressible Navier-Stokes equations in two- and three-dimensional curvilinear domains. The higher-order accuracy in time results from 1) An application of the backward differentiation formulae time-stepping algorithm (BDF) in conjunction with 2) A BDF-like extrapolation technique for certain components of the nonlinear terms (which makes use of nonlinear solves unnecessary), as well as 3) A novel application of the Douglas-Gunn splitting (which greatly facilitates handling of boundary conditions while preserving higher-order accuracy in time). As suggested by our theoretical analysis of the algorithms for a variety of special cases, an extensive set of numerical experiments clearly indicate that all of the BDF-based ADI algorithms proposed in this paper are "quasi-unconditionally stable" in the following sense: each algorithm is stable for all couples $(h,\\Delta t)$ of spatial and t...

  5. CT、MR、X线联合观察骨赘填充颈椎cage的短期融合率%The short-term fusion rate of osteophyte filled cervical cage evaluated by a combination of CT, MR and X-ray film

    Institute of Scientific and Technical Information of China (English)

    刘宁; 孙宇

    2010-01-01

    Objective To observe the short-term fusion rate of using osteophyte filled cage in ante-rior cervical disectomy and fusion. Methods From May 2007 to May 2009, 103 patients receiving anterior cervical disectomy, spine fusion by different surgeons were performed with cages containing exclusively au-tologous osteophyte collected from both anterior and posterior vertebral edges adjacent to the intervertebral space. There are 69 males, 34 females, from 25 to 77 years of age, average 53.6 years. 60 patients received one level fusion. 33 and 10 patients received two-level and three-level fusion respectively. Patients were re-viewed 3 months after operation and fusion was evaluated by X-ray film, reconstructive CT and MR. Results 1. Only 1.9% (2/103) of patients' X-ray films indicate non-fusion (internal fixation failure) while 31.7% (32/ 103) of patients' CT and 30.1% (31/103) of patients' MR indicate non-fusion or being confusing to make a diagnosis. 2. The diagnostic coherence between CT and MR as to evaluate fusion is good (kappa=0.686, P= 0.00). 3. The total fusion rate was 77.7%(80/103) while the highest fusion rate achieved by single surgeon was 90%(18/20). The total one level fusion rate was 80%(48/60) while the highest rate by single surgeon was 88.2%(15/17). The total two-level fusion rate was 78.6%(26/33) while the highest rate by single sur-geon was 90%(9/10). The total three-level fusion rate was 60%(60/100) while the highest rate by single surgeon was 100%(3/3). No statistic significant difference in fusion rate was found between any two of the three groups. Conclusion The method of using osteophyte filled cage can acquire ideal short-term fusion rate in one and two-level anterior cervical disectomy, fusion and plate fixation.%目的 观察单纯采用椎体骨赘填充cage行颈前路椎体间融合的短期融合率.方法 2007年5月至2009年5月,不同医生对103例行颈前路椎间盘切除减压、融合、钛板内固定手术的患者单纯采集

  6. Momentum Deposition in Curvilinear Coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Cleveland, Mathew Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lowrie, Robert Byron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rockefeller, Gabriel M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thompson, Kelly Glen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wollaber, Allan Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-03

    The momentum imparted into a material by thermal radiation deposition is an important physical process in astrophysics and inertial confinement fusion (ICF) simulations. In recent work we presented a new method of evaluating momentum deposition that relies on the combination of a time-averaged approximation and a numerical integration scheme. This approach robustly and efficiently evaluates the momentum deposition in spherical geometry. Future work will look to extend this approach to 2D cylindrical geometries.

  7. Study on the numerical solutions of the eikonal equationin curvilinear coordinate system%曲线坐标系程函方程的求解方法研究

    Institute of Scientific and Technical Information of China (English)

    刘一峰; 兰海强

    2012-01-01

    The classical eikonal equation is commonly used in Cartesian coordinate system for problems that involve static correction, prestack migration, earthquake location and seismic tomography, but is less effective for calculating travel times in an earth model that has an irregular surface. We transform the eikonal equation to a curvilinear coordinate system that conforms with the boundaries of the domain. The eikonal equation in the curvilinear coordinate system displays the mathematical form of an anisotropic eikonal equations (even though the medium is isotropic in the Cartesian coordinate system). Then, we try to solve the anisotropic eikonal equations with two numerical methods, a simple modification of the fast marching method and Lax-Friedrichs fast sweeping method, respectively. Through a number of different numerical experiments we find- one may compute wrong solutions by extending fast marching methods designed for isotropic eikonal equations to anisotropic eikonal equations without taking into account the differences between them; the Lax-Friedrichs fast sweeping method is stable and valid for the eikonal equation in the curvilinear coordinate system, which has a significant meaning in the direction of solution of the eikonal equation in the curvilinear coordinate system.%笛卡尔坐标系中经典的程函方程在静校正、叠前偏移、走时反演、地震定位、层析成像等许多地球物理工作都有应用,然而用其计算起伏地表的地震波走时时却比较困难.我们通过把曲线坐标系中的矩形网格映射到笛卡尔坐标系的贴体网格推导出了曲线坐标中的程函方程,此时,曲线坐标系的程函方程呈现为各向异性的程函方程(尽管在笛卡尔坐标系中介质是各向同同性的).然后尝试用求解各向同性程函方程的快速推进法和Lax-Friedrichs快速扫描算法来分别求解该方程.数值试验表明未加考虑各向异性程函方程与各向同性程函方程的差

  8. Disckectomy, Partial Adjacent Centrum Resection, Bone Graft with Titanium Mesh and Titanium Plate Fixation for the Treatment of Single Segment Cervical Disc Degeneration with Adjacent Vertebral Posterior Osteophyte%椎间盘及部分椎体切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘突出伴椎体后缘骨赘

    Institute of Scientific and Technical Information of China (English)

    孙继飞; 何强; 刘振利; 陈庆胜

    2012-01-01

    目的 评价颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘退变突出伴相邻椎体后缘骨赘的疗效. 方法 应用颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘退变突出伴相邻椎体后缘骨赘22例.取颈椎前路手术切口,术中仅切除突出的椎间盘及相邻椎体的1/3~ 1/2,使脊髓得到彻底的减压.再用填满碎骨的钛网植于骨缺损处加用钛板螺丝钉内固定,固定范围仅限于相邻椎体.术前和术后通过神经功能JOA评分、颈部轴性症状、颈椎动态侧位片和颈椎MRI比较临床疗效. 结果 均获随访,平均15(6 ~24)个月,术后JOA评分优良率86.4%,颈部轴性症状减轻,脊髓功能明显得到恢复.颈椎活动度良好.X线检查见钛网植骨及钛板内固定良好,未见不稳现象.MRI示颈髓压迫解除. 结论 颈椎椎间盘及相邻椎体部分切除加钛网植骨钛板内固定术治疗单节段颈椎椎间盘突出伴相邻椎体骨赘效果显著,可最大限度地保留颈椎节段的活动度.%Objective To evaluate the clinical effects of disckectomy, partial adjacent centrum resection , bone graft with titanium mesh and titanium plate fixation for the treatment of single segment cervical disc degeneration with adjacent vertebral posterior osteophyte. Methods There were 22 cases received this kind of surgical procedure. By anterior cervical incision, the herniated disc and only 1/3 to 1/2 of the adjacent vertebral body were removed for the decompression of the spinal cord. Then the titanium mesh filled with the small bones was implanted in the bone defect followed by titanium screw fixation. The fixation was limited to the adjacent vertebral bodies. Preoperative and postoperative neurological functions of the JOA score, the cervical axial symptoms, the cervical dynamic radiographs and cervical spine MRI were used to compare the clinical

  9. Volume Rendering for Curvilinear and Unstructured Grids

    Energy Technology Data Exchange (ETDEWEB)

    Max, N; Williams, P; Silva, C; Cook, R

    2003-03-05

    We discuss two volume rendering methods developed at Lawrence Livermore National Laboratory. The first, cell projection, renders the polygons in the projection of each cell. It requires a global visibility sort in order to composite the cells in back to front order, and we discuss several different algorithms for this sort. The second method uses regularly spaced slice planes perpendicular to the X, Y, or Z axes, which slice the cells into polygons. Both methods are supplemented with anti-aliasing techniques to deal with small cells that might fall between pixel samples or slice planes, and both have been parallelized.

  10. Particle simulation in curvilinear coordinate systems

    International Nuclear Information System (INIS)

    We present methods for particle simulation of plasmas in a nearly arbitrary coordinate metric and describe a toroidal electrostatic simulation code that evolved from this effort. A Mercier-type coordinate system is used, with a nonuniform radial grid for improved cross-field resolution. A fast iterative method for solving the Poisson equation is employed, and the interpolation/filtering technique shown to be momentum and energy conserving in the continuum limit. Lorentz ion and drift electron species are used. The code has been thoroughly tested for its reproduction of linear and nonlinear physics, and has been applied to the toroidal drift wave problem and its impact on anomalous transport in tokamaks. 40 refs., 10 figs., 1 tab

  11. Optimizing the geometrical accuracy of curvilinear meshes

    CERN Document Server

    Toulorge, Thomas; Remacle, Jean-François

    2015-01-01

    This paper presents a method to generate valid high order meshes with optimized geometrical accuracy. The high order meshing procedure starts with a linear mesh, that is subsequently curved without taking care of the validity of the high order elements. An optimization procedure is then used to both untangle invalid elements and optimize the geometrical accuracy of the mesh. Standard measures of the distance between curves are considered to evaluate the geometrical accuracy in planar two-dimensional meshes, but they prove computationally too costly for optimization purposes. A fast estimate of the geometrical accuracy, based on Taylor expansions of the curves, is introduced. An unconstrained optimization procedure based on this estimate is shown to yield significant improvements in the geometrical accuracy of high order meshes, as measured by the standard Haudorff distance between the geometrical model and the mesh. Several examples illustrate the beneficial impact of this method on CFD solutions, with a part...

  12. Analyses of crustal motion and deformation models in a curvilinear coordinate system%曲线坐标系下的块体运动与应变模型研究

    Institute of Scientific and Technical Information of China (English)

    汪建军; 许才军

    2009-01-01

    本文建立了顾及地球扁率和局部切标架随点变化特性的椭球坐标系下的刚体运动模型和块体运动与应变模型,以及球坐标系下顾及局部切标架随点变化特性的严密的块体运动与应变模型,分析了球坐标系下块体运动与应变模型及椭球坐标系下的块体运动与应变模型间的差异;通过计算具体讨论了地球扁率和曲线坐标系的局部切标架随点变化特性对欧拉矢量与应变张量的影响.结果表明:地球扁率对刚体欧拉矢量和应变参数的影响甚小,具体计算时可以不予考虑,但曲线坐标系的局部切标架随点变化特性对两者的影响较大,在建模过程中需要顾及,常用的Savage模型需要修正.%We present rigid block motion model and strain rate model in a geodetic coordinate system as well as those in a spherical coordinate system under the framework of tensor analysis. Both eccentricity and local tangential moving frame are now considered in these models,which is not the case for previous modeling. To explore the effects of these two geometrical characteristics,we investigate differences in parameters such as Euler pole and strain rate tensor by employing these models to invert them. Our results show that the eccentricity has minor effects on determining Euler pole and strain rate tensor,indicating that it is reasonable not to consider crustal motion and deformation models in a geodetic coordinate system. On the contrary,the local tangential moving frame plays a big role in changing both of them,meaning that the local frame of velocity being different at each observation site should be taken account of when one builds up strain model in a curvilinear coordinate system. Accordingly,the conventional Savage's crustal deformation model should be refurnished.

  13. New method of investigation on 3 D hydrodynamic model in curvilinear coordinates%曲线坐标系下三维水动力模型求解新方法

    Institute of Scientific and Technical Information of China (English)

    吴卫国; 沈露予; 薛世峰

    2014-01-01

    为求解三维水动力模型的高精度数值计算,设计了一种在曲线坐标系下求解的新方法。对ξ,η和ζ共3个方向的空间导数分别采用高精度的紧致有限差分以及非线性项的迎风紧致有限差分格式,时间积分则采用四阶修正Runge-Kutta显式格式。为了验证该算法求解曲线坐标系下三维水动力模型的正确性,选取与De Vriend的180°弯道水槽试验相同的物理参数进行数值试验,计算出水位、流速分布等,并将计算结果与De Vriend的试验值以及先前采用SIMPLEC法获得的数值结果进行了对比分析。结果发现:文中创建的高精度算法获得的数值解比SIMPLEC法计算的数值结果更符合试验值,通过算法定量计算得到的平均速度值与试验测量值之间产生的最大相对误差约为3%。说明构建的高精度紧致有限差分算法来数值求解三维水动力问题是可行的、合理的,为天然河道、明渠以及湖泊等水动力计算提供参考依据。%A numerical method for solving three-dimensional hydrodynamic model in curvilinear coordi-nates was presented.High-order and high-resolution compact finite difference scheme and upwind com-pact finite difference scheme for nonlinear terms were used as spatial discretization,and the time inte-gration was accomplished by 4th-order modified Runge -Kutta scheme.To verify the numerical me-thod,the same physical parameters of De Vriend's 180°curved channel test were used in the simula-tion.The results show that,the new numerical results are closer to the experimental data than the re-sults calculated by using SIMPLEC.The maximum relative error between numerical and experimental average velocity results is less than 3%.It is proved that the numerical method presented is feasible and rational.To sum up,it is an efficient,feasible and rational way to numerically solve hydrodynamic problems,and can be used in many engineering computations of

  14. 组织支持感与工作投入的曲线关系及其边界条件%The Curvilinear Relationship between Perceived Organizational Support, Work Engagement and Its Boundary Conditions

    Institute of Scientific and Technical Information of China (English)

    孙健敏; 陆欣欣; 孙嘉卿

    2015-01-01

    As a type of important job resource , perceived organizational support has been identified as a salient antecedent of work engagement .However , the extant literature has ignored that with the norm of reciprocity as its core tenet , perceived organization-al support requires reciprocation from the recipients .Then, below a certain point, employees who perceive organizational support are expected to reciprocate by performing extra-role behavior , which reduces their engagement in assigned work .Based on Job-Demand Resource model and social exchange theory , we argue that there may be U-shaped relationship between perceived organi-zational support and work engagement .Moreover, the extent to which individuals are engaged in extra-role performance is pro-foundly shaped by their affective commitment with the organization .Therefore, we propose that affective commitment moderates the curvilinear relationship between perceived organizational support and work engagement . We collected data among 302 employees with diverse positions in securities industry who self-reported the variables .Confirmatory factor analysis was conducted to detect potential Common Method Bias and the results suggested that CMB was not serious as con -cerned.Theoretical hypotheses were tested using polynomial regression .The results suggested that after controlling for affective commitment, there was U-shaped relationship between perceived organizational support and work engagement , such that only over a certain point perceived organizational support was positively related with work engagement .Moreover , the non-linear relation-ship was moderated by affective commitment .Specifically , for those with high affective commitment , perceived organizational support was related to work engagement in a U-shaped manner , whereas the relationship was linear among those with low affective commitment. Our research shed light on the negative effect of perceived organizational support on work engagement and

  15. The Curvilinear Relationship between Perceived Organizational Support, Work Engagement and Its Boundary Conditions%组织支持感与工作投入的曲线关系及其边界条件

    Institute of Scientific and Technical Information of China (English)

    孙健敏; 陆欣欣; 孙嘉卿

    2015-01-01

    As a type of important job resource , perceived organizational support has been identified as a salient antecedent of work engagement .However , the extant literature has ignored that with the norm of reciprocity as its core tenet , perceived organization-al support requires reciprocation from the recipients .Then, below a certain point, employees who perceive organizational support are expected to reciprocate by performing extra-role behavior , which reduces their engagement in assigned work .Based on Job-Demand Resource model and social exchange theory , we argue that there may be U-shaped relationship between perceived organi-zational support and work engagement .Moreover, the extent to which individuals are engaged in extra-role performance is pro-foundly shaped by their affective commitment with the organization .Therefore, we propose that affective commitment moderates the curvilinear relationship between perceived organizational support and work engagement . We collected data among 302 employees with diverse positions in securities industry who self-reported the variables .Confirmatory factor analysis was conducted to detect potential Common Method Bias and the results suggested that CMB was not serious as con -cerned.Theoretical hypotheses were tested using polynomial regression .The results suggested that after controlling for affective commitment, there was U-shaped relationship between perceived organizational support and work engagement , such that only over a certain point perceived organizational support was positively related with work engagement .Moreover , the non-linear relation-ship was moderated by affective commitment .Specifically , for those with high affective commitment , perceived organizational support was related to work engagement in a U-shaped manner , whereas the relationship was linear among those with low affective commitment. Our research shed light on the negative effect of perceived organizational support on work engagement and

  16. Neurons in the pigeon caudolateral nidopallium differentiate Pavlovian conditioned stimuli but not their associated reward value in a sign-tracking paradigm

    Science.gov (United States)

    Kasties, Nils; Starosta, Sarah; Güntürkün, Onur; Stüttgen, Maik C.

    2016-01-01

    Animals exploit visual information to identify objects, form stimulus-reward associations, and prepare appropriate behavioral responses. The nidopallium caudolaterale (NCL), an associative region of the avian endbrain, contains neurons exhibiting prominent response modulation during presentation of reward-predicting visual stimuli, but it is unclear whether neural activity represents valuation signals, stimulus properties, or sensorimotor contingencies. To test the hypothesis that NCL neurons represent stimulus value, we subjected pigeons to a Pavlovian sign-tracking paradigm in which visual cues predicted rewards differing in magnitude (large vs. small) and delay to presentation (short vs. long). Subjects’ strength of conditioned responding to visual cues reliably differentiated between predicted reward types and thus indexed valuation. The majority of NCL neurons discriminated between visual cues, with discriminability peaking shortly after stimulus onset and being maintained at lower levels throughout the stimulus presentation period. However, while some cells’ firing rates correlated with reward value, such neurons were not more frequent than expected by chance. Instead, neurons formed discernible clusters which differed in their preferred visual cue. We propose that this activity pattern constitutes a prerequisite for using visual information in more complex situations e.g. requiring value-based choices. PMID:27762287

  17. The Relationship Between Academic Supervisor Leadership and Creativity of Postgraduates:Linear or Curvilinear?%学术导师领导力与研究生创造力:直线相关还是曲线相关?

    Institute of Scientific and Technical Information of China (English)

    蒙艺; 罗长坤

    2015-01-01

    学术导师领导力是影响研究生创造力的一个重要因素。基于相关理论,提出和回答关于学术导师领导力与研究生创造力关系状态的研究问题。曲线拟合和等级回归分析677个样本数据的结果显示:学术导师领导力与创造力曲线相关,是正U型曲线关系。研究发现弥补相关理论的缺失,为学术导师领导实践和高等院校创新教育管理提供切实的参考。%Academic supervisor leadership is one of the significant factors influencing creativity of postgraduates. Based on the related theories, the research reported in this paper raises and probes into the question on the relationship between academic supervisor leadership and creativity of postgraduates. The study employs curve estimation and hierarchical regression to analyze data collected from 677 postgraduates. The results demonstrate a curvilinear (U-shaped) relationship between academic supervisor leadership and creativity of postgraduates. The findings fill the research gaps of related theories, and provide a valuable reference for leadership practice of academic supervisors and creativity management of high education.

  18. Parental competence and maltreatment: the curvilinear influence of plan complexity.

    Science.gov (United States)

    Strickland, Amanda L; Samp, Jennifer A

    2013-03-01

    A parent's ability to plan for child behavior problems was proposed to influence the relationship between parental competence and attitudes/beliefs about parenting behaviors. One hundred and one parents from three community sites completed questionnaires measuring parental competence, plan complexity, and attitudes/beliefs about parenting. Results indicated that plan complexity significantly influenced the relationship between parental competence and judgments about corporal punishment. The same influence existed between parental competence and power independence. We discuss these results with regard to forwarding theoretical work on planning processes, as well as practical implications for enhancing parent education curricula to better address the constructive management of difficult child behaviors. PMID:23027836

  19. Height among Women is Curvilinearly Related to Life History Strategy

    NARCIS (Netherlands)

    Buunk, Abraham P.; Pollet, Thomas V.; Klavina, Liga; Figueredo, Aurelio Jose; Dijkstra, Pieternel

    2009-01-01

    It was hypothesized that women of medium height would show a more secure, long-term mating pattern characterized by less jealousy, less intrasexual competition and a "slower" life history strategy. In three samples of female undergraduate students clear support was found for these hypotheses. In Stu

  20. Misperceptions in the trajectories of objects undergoing curvilinear motion.

    Science.gov (United States)

    Yilmaz, Ozgur; Tripathy, Srimant P; Ogmen, Haluk

    2012-01-01

    Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems. PMID:22615775

  1. Misperceptions in the trajectories of objects undergoing curvilinear motion.

    Directory of Open Access Journals (Sweden)

    Ozgur Yilmaz

    Full Text Available Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems.

  2. Analyzing genotype-by-environment interaction using curvilinear regression

    Directory of Open Access Journals (Sweden)

    Dulce Gamito Santinhos Pereira

    2012-12-01

    Full Text Available In the context of multi-environment trials, where a series of experiments is conducted across different environmental conditions, the analysis of the structure of genotype-by-environment interaction is an important topic. This paper presents a generalization of the joint regression analysis for the cases where the response (e.g. yield is not linear across environments and can be written as a second (or higher order polynomial or another non-linear function. After identifying the common form regression function for all genotypes, we propose a selection procedure based on the adaptation of two tests: (i a test for parallelism of regression curves; and (ii a test of coincidence for those regressions. When the hypothesis of parallelism is rejected, subgroups of genotypes where the responses are parallel (or coincident should be identified. The use of the Scheffé multiple comparison method for regression coefficients in second-order polynomials allows to group the genotypes in two types of groups: one with upward-facing concavity (i.e. potential yield growth, and the other with downward-facing concavity (i.e. the yield approaches saturation. Theoretical results for genotype comparison and genotype selection are illustrated with an example of yield from a non-orthogonal series of experiments with winter rye (Secalecereale L.. We have deleted 10 % of that data at random to show that our meteorology is fully applicable to incomplete data sets, often observed in multi-environment trials.

  3. Association between delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and joint space narrowing and osteophytes

    DEFF Research Database (Denmark)

    Owman, H; Ericsson, Y B; Englund, M;

    2014-01-01

    OBJECTIVE: To examine the association between the relaxation time (T1Gd) of delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and grade of tibiofemoral joint space narrowing (JSN) and osteophytosis 11 years later, in a cohort of meniscectomized patients. DESIGN: Patients...... (n = 45) aged 35-50 who had undergone an arthroscopic partial medial meniscectomy 1-6 years earlier, due to degenerative meniscal tear, were examined using dGEMRIC. These patients had no cartilage changes defined as deep clefts or visible bone at the time of arthroscopy. Eleven years later (12...

  4. Autofocus algorithm for synthetic aperture radar imaging with large curvilinear apertures

    International Nuclear Information System (INIS)

    An approach to autofocusing for large curved synthetic aperture radar (SAR) apertures is presented. Its essential feature is that phase corrections are being extracted not directly from SAR images, but rather from reconstructed SAR phase-history data representing windowed patches of the scene, of sizes sufficiently small to allow the linearization of the forward- and back-projection formulae. The algorithm processes data associated with each patch independently and in two steps. The first step employs a phase-gradient-type method in which phase correction compensating (possibly rapid) trajectory perturbations are estimated from the reconstructed phase history for the dominant scattering point on the patch. The second step uses phase-gradient-corrected data and extracts the absolute phase value, removing in this way phase ambiguities and reducing possible imperfections of the first stage, and providing the distances between the sensor and the scattering point with accuracy comparable to the wavelength. The features of the proposed autofocusing method are illustrated in its applications to intentionally corrupted small-scene 2006 Gotcha data. The examples include the extraction of absolute phases (ranges) for selected prominent point targets. They are then used to focus the scene and determine relative target–target distances. (paper)

  5. A multi-dimensional Smolyak collocation method in curvilinear coordinates for computing vibrational spectra.

    Science.gov (United States)

    Avila, Gustavo; Carrington, Tucker

    2015-12-01

    In this paper, we improve the collocation method for computing vibrational spectra that was presented in Avila and Carrington, Jr. [J. Chem. Phys. 139, 134114 (2013)]. Using an iterative eigensolver, energy levels and wavefunctions are determined from values of the potential on a Smolyak grid. The kinetic energy matrix-vector product is evaluated by transforming a vector labelled with (nondirect product) grid indices to a vector labelled by (nondirect product) basis indices. Both the transformation and application of the kinetic energy operator (KEO) scale favorably. Collocation facilitates dealing with complicated KEOs because it obviates the need to calculate integrals of coordinate dependent coefficients of differential operators. The ideas are tested by computing energy levels of HONO using a KEO in bond coordinates. PMID:26646870

  6. Reciprocity Theorems for One-Way Wave Fields in Curvilinear Coordinate Systems

    NARCIS (Netherlands)

    Frijlink, M.; Wapenaar, C.P.A.

    2010-01-01

    One-way wave equations conveniently describe wave propagation in media with discontinuous and/or rapid variations in one direction, but with smooth and slow variations in the complementary transverse directions. In the past, reciprocity theorems have been developed in terms of one-way wave fields. T

  7. CellFIT: a cellular force-inference toolkit using curvilinear cell boundaries.

    Directory of Open Access Journals (Sweden)

    G Wayne Brodland

    Full Text Available Mechanical forces play a key role in a wide range of biological processes, from embryogenesis to cancer metastasis, and there is considerable interest in the intuitive question, "Can cellular forces be inferred from cell shapes?" Although several groups have posited affirmative answers to this stimulating question, nagging issues remained regarding equation structure, solution uniqueness and noise sensitivity. Here we show that the mechanical and mathematical factors behind these issues can be resolved by using curved cell edges rather than straight ones. We present a new package of force-inference equations and assessment tools and denote this new package CellFIT, the Cellular Force Inference Toolkit. In this approach, cells in an image are segmented and equilibrium equations are constructed for each triple junction based solely on edge tensions and the limiting angles at which edges approach each junction. The resulting system of tension equations is generally overdetermined. As a result, solutions can be obtained even when a modest number of edges need to be removed from the analysis due to short length, poor definition, image clarity or other factors. Solving these equations yields a set of relative edge tensions whose scaling must be determined from data external to the image. In cases where intracellular pressures are also of interest, Laplace equations are constructed to relate the edge tensions, curvatures and cellular pressure differences. That system is also generally overdetermined and its solution yields a set of pressures whose offset requires reference to the surrounding medium, an open wound, or information external to the image. We show that condition numbers, residual analyses and standard errors can provide confidence information about the inferred forces and pressures. Application of CellFIT to several live and fixed biological tissues reveals considerable force variability within a cell population, significant differences between populations and elevated tensions along heterotypic boundaries.

  8. Thick-walled anisotropic elliptic tube analyzed via curvilinear tensor calculus

    Directory of Open Access Journals (Sweden)

    Mareš T.

    2007-10-01

    Full Text Available After a brief introduction into the tensor calculus, the thick-walled anisotropic elliptic tube is analyzed. A procedure of the analysis is described in a stepwise manner. A choice of the appropriate coordinate systems is the first step. The second step consists of the determination of corresponding metric tensors. Then the elasticity tensor of a local orthotropy is transformed into a global computational coordinate system. Next the appropriate Christoffel symbols of the second kind are determined and the total potential energy of the system is expressed. At the end the solution is approximated by a Fourier series and for given geometrical values and loading the numerical results are obtained and graphically represented.It must be said that throughout the calculation the free software only was used and for the numerical operations an old laptop is sufficient. The author regards both the former and the latter as a great advantage of the demonstrated method.

  9. A multi-dimensional Smolyak collocation method in curvilinear coordinates for computing vibrational spectra

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Gustavo, E-mail: Gustavo-Avila@telefonica.net; Carrington, Tucker, E-mail: Tucker.Carrington@queensu.ca [Chemistry Department, Queen’s University, Kingston, Ontario K7L 3N6 (Canada)

    2015-12-07

    In this paper, we improve the collocation method for computing vibrational spectra that was presented in Avila and Carrington, Jr. [J. Chem. Phys. 139, 134114 (2013)]. Using an iterative eigensolver, energy levels and wavefunctions are determined from values of the potential on a Smolyak grid. The kinetic energy matrix-vector product is evaluated by transforming a vector labelled with (nondirect product) grid indices to a vector labelled by (nondirect product) basis indices. Both the transformation and application of the kinetic energy operator (KEO) scale favorably. Collocation facilitates dealing with complicated KEOs because it obviates the need to calculate integrals of coordinate dependent coefficients of differential operators. The ideas are tested by computing energy levels of HONO using a KEO in bond coordinates.

  10. APPLIED PROBLEMS OF CURVILINEAR MOTION DYNAMICS OF ALL-WHEEL DRIVE TRACTION MEANS

    Directory of Open Access Journals (Sweden)

    G. S. Gorin

    2014-01-01

    Full Text Available Fundamental principles for hybrid theory on turning of an all-wheel drive system are given in the paper. The paper shows expediency of accounting longitudinal additional tangential reactions (parasitic forces in contacts of central and lateral wheels with foundation. Algorithms for calculating additional tangential reactions have been proposed in the paper. The paper presents calculation kinematics model for turning of steered and rigid bogie with inter-wheel differential at various axial drive.

  11. A Hybrid PO - Higher-Order Hierarchical MoM Formulation using Curvilinear Geometry Modeling

    OpenAIRE

    Jørgensen, E; Meincke, Peter; Breinbjerg, Olav

    2003-01-01

    A very efficient hybrid PO-MoM method has been presented. In contrast to existing methods, the present solution employs higher-order hierarchical basis functions to discretize the MoM and PO currents. This allows to reduce the number of basis functions in both the PO and MoM regions considerably which implies a very modest memory requirement. Nevertheless, the hierarchical feature of the basis functions maintains the ability to treat small geometrical details efficiently. In addition, the sca...

  12. A Hybrid PO - Higher-Order Hierarchical MoM Formulation using Curvilinear Geometry Modeling

    DEFF Research Database (Denmark)

    Jørgensen, E.; Meincke, Peter; Breinbjerg, Olav

    2003-01-01

    A very efficient hybrid PO-MoM method has been presented. In contrast to existing methods, the present solution employs higher-order hierarchical basis functions to discretize the MoM and PO currents. This allows to reduce the number of basis functions in both the PO and MoM regions considerably...

  13. Simulation of 2-D Compressible Flows on a Moving Curvilinear Mesh with an Implicit-Explicit Runge-Kutta Method

    KAUST Repository

    AbuAlSaud, Moataz

    2012-07-01

    The purpose of this thesis is to solve unsteady two-dimensional compressible Navier-Stokes equations for a moving mesh using implicit explicit (IMEX) Runge- Kutta scheme. The moving mesh is implemented in the equations using Arbitrary Lagrangian Eulerian (ALE) formulation. The inviscid part of the equation is explicitly solved using second-order Godunov method, whereas the viscous part is calculated implicitly. We simulate subsonic compressible flow over static NACA-0012 airfoil at different angle of attacks. Finally, the moving mesh is examined via oscillating the airfoil between angle of attack = 0 and = 20 harmonically. It is observed that the numerical solution matches the experimental and numerical results in the literature to within 20%.

  14. Perceived parental differential treatment in middle adulthood: curvilinear relations with individuals' experienced relationship quality to sibling and parents.

    Science.gov (United States)

    Boll, Thomas; Ferring, Dieter; Filipp, Sigrun-Heide

    2003-12-01

    Guided by predictions from equity theory and the self-esteem maintenance model, links between perceptions of current parental differential treatment and the perceiver's experienced relationship quality with sibling and parents were analyzed in a sample of 1,020 adult (middle-aged) offspring. Participants rated how often they and a sibling receive parental recognition, nurture, and demands for filial responsibility. In addition, they indicated their emotions and behaviors toward sibling and parents. Data analyses showed that an individual's experienced relationship with sibling was best when both were treated equally and diminished with increasing favoritism or disfavoritism. Experienced relationship with parents was best when participants were favored a bit; the relationship worsened when participants were disfavored and worsened only slightly when they were extremely favored. Results are discussed regarding mediating processes and implications for practical applications. PMID:14640798

  15. A speed of sound aberration correction algorithm for curvilinear ultrasound transducers in ultrasound-based image-guided radiotherapy

    Science.gov (United States)

    Fontanarosa, Davide; Pesente, Silvia; Pascoli, Francesco; Ermacora, Denis; Abu Rumeileh, Imad; Verhaegen, Frank

    2013-03-01

    Conventional ultrasound (US) devices use the time of flight (TOF) of reflected US pulses to calculate distances inside the scanned tissues and thus create images. The speed of sound (SOS) is assumed to be constant in all human soft tissues at a generally accepted average value of 1540 m s-1. This assumption is a source of systematic errors up to several millimeters and of image distortion in quantitative US imaging. In this work, an extension of a method recently published by Fontanarosa et al (2011 Med. Phys. 38 2665-73) is presented: the aim is to correct SOS aberrations in three-dimensional (3D) US images in those cases where a spatially co-registered computerized tomography (CT) scan is also available; the algorithm is then applicable to a more general case where the lines of view (LOV) of the US device are not necessarily parallel and coplanar, thus allowing correction also for US transducers other than linear. The algorithm was applied on a multi-modality pelvic US phantom, scanned through three different liquid layers on top of the phantom with different SOS values; the results show that the correction restores a better match between the CT and the US images, reducing the differences to sub-millimeter agreement. Fifteen clinical cases of prostate cancer patients were also investigated: the SOS corrections of prostate centroids were on average +3.1 mm (max + 4.9 mm-min + 1.3 mm). This is in excellent agreement with reports in the literature on differences between measured prostate positions by US and other techniques, where often the discrepancy was attributed to other causes.

  16. When do emotionally exhausted employees speak up? Exploring the potential curvilinear relationship between emotional exhaustion and voice

    OpenAIRE

    Qin, Xin; Direnzo, Marco S.; Xu, Minya; Duan, Yilong

    2014-01-01

    Two studies were conducted to address the potential nonlinear relationship between emotional exhaustion and voice. Study 1 developed and tested a model rooted in conservation of resources theory in which responses to emotional exhaustion are determined by individual-level and group-level conditions that influence the perceived safety and efficacy of voice and drive prohibitive voice behaviors by giving rise to either resource-conservation-based or resource-acquisition-based motiva...

  17. Fairness perceptions as a moderator in the curvilinear relationships between job demands, and job performance and job satisfaction

    NARCIS (Netherlands)

    Janssen, O

    2001-01-01

    Activation theory suggests that intermediate rather than low or high levels of quantitative job demands benefit job performance and job satisfaction among managers. Using an equity theory framework, I hypothesize that perceptions of effort-reward fairness moderate these inverted U-shaped demand-resp

  18. Flow pattern transition accompanied with sudden growth of flow resistance in two-dimensional curvilinear viscoelastic flows.

    Science.gov (United States)

    Yatou, Hiroki

    2010-09-01

    We numerically find three types of steady solutions of viscoelastic flows and flow pattern transitions between them in a two-dimensional wavy-walled channel for low to moderate Weissenberg (Wi) and Reynolds (Re) numbers using a spectral element method. The solutions are called "convective," "transition," and "elastic" in ascending order of Wi. In the convective region in the Wi-Re parameter space, convective effect and pressure gradient balance on average. As Wi increases, elastic effect becomes comparable, and the first transition sets in. Through the transition, a separation vortex disappears, and a jet flow induced close to the wall by the viscoelasticity moves into the bulk; the viscous drag significantly drops, and the elastic wall friction rises sharply. This transition is caused by an elastic force in the streamwise direction due to the competition of the convective and elastic effects. In the transition region, the convective and elastic effects balance. When the elastic effect becomes greater than the convective effect, the second transition occurs but it is relatively moderate. The second transition seems to be governed by the so-called Weissenberg effect. These transitions are not sensitive to driving forces. By a scaling analysis, it is shown that the stress component is proportional to the Reynolds number on the boundary of the first transition in the Wi-Re space. This scaling coincides well with the numerical result.

  19. Flow pattern transition accompanied with sudden growth of flow resistance in two-dimensional curvilinear viscoelastic flows

    CERN Document Server

    Yatou, Hiroki

    2010-01-01

    We find three types of steady solutions and remarkable flow pattern transitions between them in a two-dimensional wavy-walled channel for low to moderate Reynolds (Re) and Weissenberg (Wi) numbers using direct numerical simulations with spectral element method. The solutions are called "convective", "transition", and "elastic" in ascending order of Wi. In the convective region in the Re-Wi parameter space, the convective effect and the pressure gradient balance on average. As Wi increases, the elastic effect becomes suddenly comparable and the first transition sets in. Through the transition, a separation vortex disappears and a jet flow induced close to the wall by the viscoelasticity moves into the bulk; The viscous drag significantly drops and the elastic wall friction rises sharply. This transition is caused by an elastic force in the streamwise direction due to the competition of the convective and elastic effects. In the transition region, the convective and elastic effects balance. When the elastic eff...

  20. Flow pattern transition accompanied with sudden growth of flow resistance in two-dimensional curvilinear viscoelastic flows

    OpenAIRE

    Yatou, Hiroki

    2010-01-01

    We find three types of steady solutions and remarkable flow pattern transitions between them in a two-dimensional wavy-walled channel for low to moderate Reynolds (Re) and Weissenberg (Wi) numbers using direct numerical simulations with spectral element method. The solutions are called "convective", "transition", and "elastic" in ascending order of Wi. In the convective region in the Re-Wi parameter space, the convective effect and the pressure gradient balance on average. As Wi increases, th...

  1. How Much Diversity Is Enough? The Curvilinear Relationship between College Diversity Interactions and First-Year Student Outcomes

    Science.gov (United States)

    Bowman, Nicholas A.

    2013-01-01

    Recent legal challenges to race-conscious college admissions processes have called into question what constitutes a sufficient level of diversity on college campuses. Previous research on the educational benefits of diversity has examined the linear relationship between diversity interactions and student outcomes, but multiple theoretical…

  2. When are workload and workplace learning opportunities related in a curvilinear manner? The moderating role of autonomy

    OpenAIRE

    Van Ruysseveldt, Joris; Van Dijke, Marius

    2011-01-01

    textabstractBuilding on theoretical frameworks like the Job Demands Control model and Action Theory we tested whether the relationship between workload and employees’ experiences of opportunities for workplace learning is of an inverted u-shaped nature and whether autonomy moderates this relationship. We predicted that – at moderate levels of autonomy - workload was positively associated with learning opportunities at low levels of workload, but negatively at high levels of workload. Also, we...

  3. Completion rates of anterior and posterior continuous curvilinear capsulorrhexis in pediatric cataract surgery for surgery performed by trainee surgeons with the use of a low-cost viscoelastic

    Directory of Open Access Journals (Sweden)

    R Muralidhar

    2012-01-01

    Full Text Available Context : Pediatric cataract surgery is traditionally done with the aid of high-molecular-weight viscoelastics which are expensive. It needs to be determined if low-cost substitutes are just as successful. Aims : The study aims to determine the success rates for anterior and posterior capsulorrhexis and intraocular lens (IOL implantation in the bag for pediatric cataract surgery performed with the aid of a low-molecular-weight viscoelastic. Settings and Design : Nonrandomized observational study. Materials and Methods: Children less than 6 years of age who underwent cataract surgery with IOL implantation in the period May 2008-May 2009 were included. The surgeries were done by pediatric ophthalmology fellows. A standard procedure of anterior capsulorrhexis, lens aspiration with primary posterior capsulorrhexis, anterior vitrectomy, and IOL implantation was followed. Three parameters were studied: successful completion of anterior and posterior capsulorrhexis and IOL implantation in the bag. Results: 33 eyes of 28 children were studied. The success rate for completion was 66.7% and 88.2 % for anterior and posterior capsulorrhexis, respectively. IOL implantation in the bag was successful in 87.9%. Conclusions: 2% hydroxypropylmethylcellulose is a viable low-cost alternative to more expensive options similar to high-molecular-weight viscoelastics. This is of great relevance to hospitals in developing countries.

  4. Implicit solution of Navier-Stokes equations on staggered curvilinear grids using a Newton-Krylov method with a novel analytical Jacobian.

    Science.gov (United States)

    Borazjani, Iman; Asgharzadeh, Hafez

    2015-11-01

    Flow simulations involving complex geometries and moving boundaries suffer from time-step size restriction and low convergence rates with explicit and semi-implicit schemes. Implicit schemes can be used to overcome these restrictions. However, implementing implicit solver for nonlinear equations including Navier-Stokes is not straightforward. Newton-Krylov subspace methods (NKMs) are one of the most advanced iterative methods to solve non-linear equations such as implicit descritization of the Navier-Stokes equation. The efficiency of NKMs massively depends on the Jacobian formation method, e.g., automatic differentiation is very expensive, and matrix-free methods slow down as the mesh is refined. Analytical Jacobian is inexpensive method, but derivation of analytical Jacobian for Navier-Stokes equation on staggered grid is challenging. The NKM with a novel analytical Jacobian was developed and validated against Taylor-Green vortex and pulsatile flow in a 90 degree bend. The developed method successfully handled the complex geometries such as an intracranial aneurysm with multiple overset grids, and immersed boundaries. It is shown that the NKM with an analytical Jacobian is 3 to 25 times faster than the fixed-point implicit Runge-Kutta method, and more than 100 times faster than automatic differentiation depending on the grid (size) and the flow problem. The developed methods are fully parallelized with parallel efficiency of 80-90% on the problems tested.

  5. A three-dimensional solid-liquid two-phase turbulence model with the effect of vegetation in non-orthogonal curvilinear coordinates

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng; SHEN YongMing

    2009-01-01

    A three-dimensional k-ε-Ap solid-liquid two-phase two-fluid model with the effect of vegetation Is solved numerically with a finite-volume method on an adaptive grid to study water-sediment movements and bed evolution in vegetated channels. The additional drag force and additional turbulence generation due to vegetation are added to the relevant control equations for simulating the interaction between vegetation and flow. The flow structure and the bed-topography changes in a 60° partly vegetated channel bend are calculated by the model. The numerical results agree well with the measured ones. Calculated and measured results show that the primary flow velocity reduces much in the vegetation zone and increases in the non-vegetation zone, the secondary flow velocity weakens in the vegetation zone and strengthens in the non-vegetation zone, the sediment movement and bed-topography change also weaken in the vegetation zone and strengthen in the non-vegetation zone, a well-planed vegetation arrangement can improve bank stabilization program, and the k-ε-Ap model can deal with bed-load transport with a more reasonable method than the one-fluid model.

  6. Total Knee Replacement for Women

    Medline Plus

    Full Text Available ... It’s important to maintain this as a contiguous soft tissue flap, which will be important for closure. When ... osteophytes out. You have less tethering of the soft tissue over those osteophytes. Ken, how often do you ...

  7. Diffuse idiopathic skeletal hyperostosis of cervical spine - An unusual cause of difficult flexible fiber optic intubation

    Directory of Open Access Journals (Sweden)

    Baxi Vaibhavi

    2010-01-01

    Full Text Available This is a report of anterior osteophytes on the cervical vertebra resulting in distortion of the airway and leading to difficulty during intubation. The osteophytes associated with the syndrome of diffuse idiopathic skeletal hyperostosis were at the C2-3 and C6-7, T1 level and resulted in anterior displacement of the pharynx and the trachea respectively.

  8. Triamcinolone acetonide activates an anti-inflammatory and folate receptor-positive macrophage that prevents osteophytosis in vivo

    NARCIS (Netherlands)

    Siebelt, Michiel; Korthagen, Nicoline; Wei, Wu; Groen, Harald; Bastiaansen-Jenniskens, Yvonne; Müller, Christina; Waarsing, Jan Hendrik; de Jong, Marion; Weinans, Harrie

    2015-01-01

    INTRODUCTION: Triamcinolone acetonide (TA) is used for osteoarthritis management to reduce pain, and pre-clinical studies have shown that TA limits osteophyte formation. Osteophyte formation is known to be facilitated by synovial macrophage activation. TA injections might influence macrophage activa

  9. Application of TVD scheme to numerical simulation of 2-D surge in curvilinear coordinates%曲线坐标网格下二维涌波数值模拟的TVD型格式

    Institute of Scientific and Technical Information of China (English)

    王如云; 张东生; 张长宽; 朱寿峰

    2002-01-01

    针对水动力学中的涌波现象导出二维曲线坐标系下的守恒型方程,然后利用算子分裂法和TVD差分格式思想构造出计算格式,在此基础上建立起由实际流场区域至方形计算区域的全局同胚映射,对急流过缩窄河道产生的涌波结构进行数值模拟,结果表明,本文的数值方法能够很好地模拟附体涌波、交叉涌波等复杂结构现象,所得波系结构和有关物理量与理论分析结果非常吻合,表明本文的数值方法对于模拟水动力学中的涌波现象是可行的.

  10. Intra- and interobserver agreement of computed tomography in assessment of the mandibular condyle

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Bong Hae; Jung, Yun Hoa [Pusan National Univ. College of Dentistry, Pusan (Korea, Republic of)

    2007-12-15

    To study the intra- and interobserver agreement of multidetector row computed tomography (MDCT) in interpretation of degenerative changes of the mandibular condyle. Five observers independently evaluated one hundred temporomandibular joint MDCT images for signs of osteophytes, erosion, sclerosis and flattening. The intra- and interobserve agreements were calculated by using Kappa statistics. The intraobserver agreement was substantial for erosion (k=0.75), flattening (k=0.74) and sclerosis (k=0.72) and almost perfect for osteophytes (k=0.84). The interobserver agreement was fair for flattening (k=0.39), moderate for erosion (k=0.58) and sclerosis (k=0.48) and substantial for osteophytes (k=0.75). This study shows that we can expert good agreement for the presence of osteophytes, but not for flattening in the interpretation of MDCT images of the condyle.

  11. Impaled aorta: a rare case of aortic perforation with a vertebral outgrowth.

    Science.gov (United States)

    Afifi, Rana O; Sandhu, Harleen K; Fraser, Charles D; Estrera, Anthony L

    2015-04-01

    We describe an unusual case of aortic perforation by a vertebral osteophyte, complicated by a mycotic pseudoaneurysm, in a patient who underwent successful repair. To our knowledge, no similar case has been reported previously.

  12. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... severe osteoarthritis. He does not have a really big inferior osteophyte. Has a little bit of proximal ... that you can do to give yourself a big break as far as glenoid exposure is concerned ...

  13. Anterior Approach Total Hip Replacement

    Medline Plus

    Full Text Available ... dysplasia with cystic changes and loss of joint space. No real significant osteophytes we’re going to ... sort of used to looking at things in space. I agree completely. But when you put your ...

  14. Reverse Shoulder Arthroplasty

    Medline Plus

    Full Text Available ... out the plexus or the nerves, there are large osteophytes that might get in the way, or ... And since we couldn’t quite fit the large -- the second reamer, in here, we're just ...

  15. 寰枕膜松解术配合颈椎调衡术治疗椎动脉型颈椎病216例%Treatment of cervical spondylopathy of carotid type with relaxation of atloido- occipital membrane combing cervical vertebrae rebalancing operation

    Institute of Scientific and Technical Information of China (English)

    姜永庆; 杨显声; 陈立民

    2002-01-01

    @@ Background:Cervical spondylopathy is generally called for a series of symptoms because of ischemia of the head caused by compression of stimulation of the carotid artery by proliferated osteophyte around cervical vertebrae or spasmic muscle or tissue cord.

  16. Anatomic Total Shoulder System

    Medline Plus

    Full Text Available ... patient is a 78-year-old male who has osteoarthritis of his left shoulder. If you look ... does not have a really big inferior osteophyte. Has a little bit of proximal migration and even ...

  17. Risk Factors for the Development of Adjacent Segment Disease Following Anterior Cervical Arthrodesis

    OpenAIRE

    Ezgi Akar; Mehmet Ufuk Akmil; Merih İş

    2015-01-01

    Aim: The aim of this study was to clinically and radiologically evaluate the efficacy of anterior cervical discectomy and fusion (ACDF) in the treatment of adjacent level degeneration. Methods: We retrospectively evaluated 89 patients (55 females, 34 males) who underwent ACDF. Adjacent segment degeneration findings were evaluated by investigating new osteophyte formation, growth of existing osteophytes, ossification of the anterior longitudinal ligament, presence of inter...

  18. COMPARISONS AMONG RADIOGRAPHY, ULTRASONOGRAPHY AND COMPUTED TOMOGRAPHY FOR EX VIVO CHARACTERIZATION OF STIFLE OSTEOARTHRITIS IN THE HORSE.

    Science.gov (United States)

    De Lasalle, Julie; Alexander, Kate; Olive, Julien; Laverty, Sheila

    2016-09-01

    A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US evaluations were performed on 23 equine cadaver stifles and compared with ME. Significant associations were found between osteophyte global scores for all imaging modalities (CT, P ˂ 0.0001; XR, P = 0.005; US, P = 0.04) vs. ME osteophyte global scores. Osteophytes were detected most frequently in the medial femorotibial (MFT) joint. A specific pattern of osteophytes was observed, with a long ridge of new bone at the insertion of the MFT joint capsule cranially on the medial femoral condyle. A novel caudo-10°proximo-5°lateral-cranio-disto-medial oblique radiographic projection was helpful for detection of intercondylar osteophytes. Multiplanar CT reformatted images were helpful for characterizing all osteophytes. Osteophyte grades at most sites did not differ among modalities. Low sensitivity/specificity for subchondral bone sclerosis and flattening of femoral condyles suggested that these signs may not be reliable radiographic and CT indicators of equine stifle OA. Equine stifle OA was associated with a decrease in BMD and specific sites of focal subchondral bone resorption/cyst formation were found in some specimens. PMID:27237699

  19. Initial responses of articular tissues in a murine high-fat diet-induced osteoarthritis model: pivotal role of the IPFP as a cytokine fountain.

    Directory of Open Access Journals (Sweden)

    Munetaka Iwata

    Full Text Available Obesity and high body mass index are associated with a higher incidence of osteoarthritis (OA. The aim of this study is to investigate the involvement of the infrapatellar fat pad (IPFP in the sub-acute effect of a high fat diet (HFD on the development of knee-OA. C57BL/6J male mice were fed either a HFD or a normal diet beginning at seven weeks of age. Tissue sections were evaluated with immunohistological analysis. The IPFP was excised, and mRNA expression profiles were compared using real-time RT-PCR analysis. Osteoarthritic changes were initiated in the HFD group after eight weeks of the HFD. Increased synovial cell number and angiogenesis at the anterior edge of the tibial plateau were exhibited prior to osteophyte formation. Quantitative histological analysis indicated that osteophyte volume was significantly increased in the HFD group after eight weeks, along with an increase in the IPFP volume, the size of individual adipocytes and the number of vessels in the IPFP. Histomorphometrical analysis revealed osteophyte area was significantly associated with IPFP area, individual adipocyte area and vascular area. Real-time RT-PCR analysis demonstrated elevated mRNA expression of inflammatory cytokines, growth factor, and adipokines in the IPFP after eight weeks of the HFD. These findings are in parallel with increased expression of the CD68 macrophage marker after eight weeks of the HFD. Expression levels of the adipokines were significantly correlated with expression of TNF-α, VEGF and TGF-β. Immunohistological analysis revealed that the Nampt protein was highly expressed in the IPFP especially around the site of osteophyte formation. Apoptosis and proliferation of chondrocytes were both enhanced at the site of osteophyte formation, indicating higher cell turnover at this region. These observations suggest the IPFP plays a pivotal role in the formation of osteophytes and functions as a secretory organ in response to a HFD.

  20. A rare complication of scaphoid nonunion: Multiple flexor tendon lesions. A case report and review of literature.

    Science.gov (United States)

    Pierrart, J; Rétoré, J-Y; Leclercq, C

    2016-04-01

    This case report describes a patient who presented with a complete rupture of the flexor pollicis longus (FPL) tendon and partial rupture of the flexor digitorum profundus of the index finger, secondary to scaphoid nonunion. This is a rare, late complication that deserves to be described because of the potential diagnostic confusion with anterior interosseous nerve palsy. No case has been reported since 1999 in the literature. The mechanism was an attrition rupture due to sharp osteophytes. The scaphoid osteophytes were removed and the FPL was repaired by tendon transfer. The results were satisfactory at the last follow-up. PMID:27117128

  1. Dynamic equations for curved submerged floating tunnel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In virtue of reference Cartesian coordinates, geometrical relations of spatial curved structure are presented in orthogonal curvilinear coordinates. Dynamic equations for helical girder are derived by Hamilton principle. These equations indicate that four generalized displacements are coupled with each other. When spatial structure degenerates into planar curvilinear structure, two generalized displacements in two perpendicular planes are coupled with each other. Dynamic equations for arbitrary curvilinear structure may be obtained by the method used in this paper.

  2. Dynamic ASE Modeling and Optimization of Aircraft with SpaRibs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose development and demonstration of a dynamic aeroservoelastic modeling and optimization system based on curvilinear internal structural arrangements of...

  3. Effect of background region of interest and time-interval selection on glomerular filtration ratio estimation by percentage dose uptake of (99m)Tc-DTPA in comparison with (51)Cr-EDTA clearance in healthy cats.

    Science.gov (United States)

    Debruyn, Katrien; Vandermeulen, Eva; Saunders, Jimmy H; Dobbeleir, André A; Ham, Hamphrey R; Peremans, Kathelijne

    2013-08-01

    Evaluation of glomerular function is a useful part of the diagnostic approach in animals suspected of having renal disease. Time-interval and background region of interest (bg ROI) selection are determining factors when calculating the glomerular filtration ratio (GFR) based on percentage uptake of (99m)technetium-labelled diethylene triamine penta-acetic acid ((99m)Tc-DTPA). Therefore, three different time intervals (60-120 s, 120-180 s, 60-180 s) and three different bg ROIs (C-shape, caudolateral, cranial + caudal) were investigated. In addition, global GFRs based on percentage dose uptake of (99m)Tc-DTPA for the different time-intervals and bg ROIs were compared with the global GFR based on (51)chromium-ethylene diaminic tetra-acetic acid ((51)Cr-EDTA) plasma clearance in nine healthy European domestic shorthair cats. Paired Student's t-tests and linear regression analysis were used to analyse the data. Different time intervals seemed to cause significant variation (P <0.01) in absolute GFR values, regardless of the choice of bg ROI. Significant differences (P <0.01) between bg ROIs were only observed in the 120-180s time interval between the C-shape and cranial + caudal bg ROI, and between the caudolateral and cranial + caudal bg ROI. The caudolateral bg ROI in the 60-180 s time interval showed the highest correlation coefficient (r = 0.882) between (99m)Tc-DTPA and (51)Cr-EDTA, although a significant difference (P <0.05) was present between both techniques. PMID:23349527

  4. Ultrasound findings of the locked metacarpophalangeal joint

    Energy Technology Data Exchange (ETDEWEB)

    Wessely, Kathryn; Healy, Jeremiah; Lee, Justin [Chelsea and Westminster Hospital, Department of Radiology, London (United Kingdom); Owers, Kate [Chelsea and Westminster Hospital, Department of Trauma and Orthopaedics Hand Unit, London (United Kingdom)

    2009-01-15

    The radiographs and sonographic findings of two cases of locked metacarpophalangeal joint secondary to tethering of the volar plate are described. The presence of osteophytes and the dynamic ultrasound assessment of the volar plate have provided confirmation of the clinical diagnosis prior to surgery. (orig.)

  5. Dysphagia due to anterior cervical osteophytosis: case report

    OpenAIRE

    Frederico Miguel Santos Silva Marquez Correia; João Paulo de Sousa Goucha Jorge; Ana Sofia Teixeira Neves; Gabriel Filipe Gonçalves Xavier; Marco Miguel Barroso de Oliveira; José Eduardo Paiva Ferreira

    2014-01-01

    The objective of this study is to highlight the possibility of dysphagia induced by anterior cervical osteophytes. When not diagnosed early this condition may be responsible for complications such as severe dysphagia and potential lung aspiration, especially in elderly patients. Analysis of a case report of a 72-year old woman who presented cervical pain and progressive dysphagia. Imaging studies have shown anterior ce...

  6. The rationale of postoperative radiographs after cervical anterior discectomy with stand-alone cage for radicular pain.

    NARCIS (Netherlands)

    Bartels, R.H.M.A.; Beems, T.; Schutte, P.J.; Verbeek, A.L.M.

    2010-01-01

    OBJECT: Cervical anterior discectomy with stand-alone cage (CADC) placement is a known treatment for cervical radiculopathy due to a herniated intervertebral disc or an osteophyte. Routine radiographs are obtained at regular postoperative intervals, but the consequences of routinely obtained radiogr

  7. Structural joint changes, malalignment, and laxity in osteoarthritis of the knee

    NARCIS (Netherlands)

    Esch, van der M.; Steultjens, M.P.; Wieringa, H.; Dinant, H.; Dekker, J.

    2005-01-01

    OBJECTIVE: To assess the relationship between (i) structural joint changes (i.e. joint space narrowing and osteophyte formation) and laxity and (ii) joint malalignment and laxity in osteoarthritis (OA) of the knee. METHODS: A cross-sectional study was carried out on 35 outpatients with osteoarthriti

  8. Bone scintigraphy in chronic knee pain: comparison with magnetic resonance imaging

    Science.gov (United States)

    Boegard, T.; Rudling, O.; Dahlstrom, J.; Dirksen, H.; Petersson, I.; Jonsson, K.

    1999-01-01

    OBJECTIVE—To compare increased bone uptake of 99Tcm-MDP and magnetic resonance (MR) detected subchondral lesions, osteophytes, and cartilage defects in the knee in middle aged people with longstanding knee pain.
METHODS—Fifty eight people (aged 41-58 years, mean 50) with chronic knee pain, with or without radiographic knee osteoarthritis, were examined with bone scintigraphy. The pattern and the grade of increased bone uptake was assessed. On the same day, a MR examination on a 1.0 T imager was performed. The presence and the grade of subchondral lesions, osteophytes, and cartilage defects were registered.
RESULTS—The κ values describing the correlation between increased bone uptake and MR detected subchondral lesions varied between 0.79 and 0.49, and between increased bone uptake and MR detected osteophytes or cartilage defects the values were <0.54. The κ values describing the correlation between the grade of bone uptake and the grade of the different MR findings was <0.57.
CONCLUSIONS—Good agreement was found between increased bone uptake and MR detected subchondral lesion. The agreement between increased bone uptake and osteophytes or cartilage defects was in general poor as well as the agreement between the grade of bone uptake and the grade of the MR findings.

 Keywords: knee; osteoarthritis; magnetic resonance imaging; bone scintigraphy PMID:10343536

  9. Anterior cervical fusion versus minimally invasive posterior keyhole decompression for cervical radiculopathy

    Directory of Open Access Journals (Sweden)

    Richard M. Young

    2015-12-01

    Conclusion: ACDF has been demonstrated to be an effective surgical procedure in treating degenerative spine disease in patients with radiculopathy and/or myelopathy. However, in a population with isolated radiculopathy and radiological imaging confirming an anterolateral disc or osteophyte complex, the MIPKF can provide similar results without the associated risks that accompany an anterior cervical spine fusion.

  10. Comparison of Diagnostic Performance of Semi-Quantitative Knee Ultrasound and Knee Radiography with MRI: Oulu Knee Osteoarthritis Study.

    Science.gov (United States)

    Podlipská, Jana; Guermazi, Ali; Lehenkari, Petri; Niinimäki, Jaakko; Roemer, Frank W; Arokoski, Jari P; Kaukinen, Päivi; Liukkonen, Esa; Lammentausta, Eveliina; Nieminen, Miika T; Tervonen, Osmo; Koski, Juhani M; Saarakkala, Simo

    2016-01-01

    Osteoarthritis (OA) is a common degenerative musculoskeletal disease highly prevalent in aging societies worldwide. Traditionally, knee OA is diagnosed using conventional radiography. However, structural changes of articular cartilage or menisci cannot be directly evaluated using this method. On the other hand, ultrasound is a promising tool able to provide direct information on soft tissue degeneration. The aim of our study was to systematically determine the site-specific diagnostic performance of semi-quantitative ultrasound grading of knee femoral articular cartilage, osteophytes and meniscal extrusion, and of radiographic assessment of joint space narrowing and osteophytes, using MRI as a reference standard. Eighty asymptomatic and 79 symptomatic subjects with mean age of 57.7 years were included in the study. Ultrasound performed best in the assessment of femoral medial and lateral osteophytes, and medial meniscal extrusion. In comparison to radiography, ultrasound performed better or at least equally well in identification of tibio-femoral osteophytes, medial meniscal extrusion and medial femoral cartilage morphological degeneration. Ultrasound provides relevant additional diagnostic information on tissue-specific morphological changes not depicted by conventional radiography. Consequently, the use of ultrasound as a complementary imaging tool along with radiography may enable more accurate and cost-effective diagnostics of knee osteoarthritis at the primary healthcare level. PMID:26926836

  11. Prevalence of knee abnormalities in patients with osteoarthritis and anterior cruciate ligament injury identified with peripheral magnetic resonance imaging: a pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada)]. E-mail: wuh5@mcmaster.ca; Webber, C. [Hamilton Health Sciences, Dept. of Nuclear Medicine, Hamilton, Ontario (Canada); McMaster Univ., Dept. of Radiology, Hamilton, Ontario (Canada); Fuentes, C.O. [Hamilton Health Sciences, Dept. of Radiology, Hamilton, Ontario (Canada); Benson, R.; Beattie, K. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada); Adachi, J.D.; Xie, X. [McMaster Univ., Dept. of Medical Sciences, Hamilton, Ontario (Canada); Jabbari, F. [Hamilton Health Sciences, Hamilton, Ontario (Canada); Levy, D.R. [McMaster Univ., Sports Medicine, Dept. of Family Medicine and Dept. of Medicine, Hamilton, Ontario (Canada)

    2007-06-15

    To assess, with a peripheral magnetic resonance imaging system (pMRI), the prevalence of bony and soft tissue abnormalities in the knee joints of normal subjects, osteoarthritis (OA) patients, and individuals who have suffered an anterior cruciate ligament (ACL) rupture; and 2) to compare the prevalence among groups. Magnetic resonance (MR) images of 28 healthy, 32 OA, and 26 ACL damaged knees were acquired with a 1.0-T pMRI system. Two radiologists grade the presence and severity of 9 MR image features: cartilage degeneration, osteophytes, subchondral cyst, bone marrow edema, meniscal abnormality, ligament integrity, loose bodies, popliteal cysts, and joint effusion. Ten of 28 healthy (35.7%), 24 of 26 ACL (92.3%), and all OA knees (100%) showed prevalent cartilage defects; 5 healthy (17.9%), 20 ACL (76.9%), and all OA knees (100%) had osteophytes; and 9 normal (32.1%), 21 ACL (80.8%), and 29 OA knees (90.6%) had meniscal abnormalities. One-half of the knees in the OA group (16 of 32, 50%) had subchondral cysts, and almost one-half had bone marrow edema (15 of 32, 46.9%). These features were not common in the ACL group (7.7%, and 11.5%, respectively) and were not observed in healthy knees. The OA group had the most severe cartilage defects, osteophytes, bone marrow edema, subchondral cysts, and meniscal abnormalities; the ACL group showed more severe cartilage defects, osteophytes, and meniscal abnormalities than did normal subjects. The results suggest that knees that have sustained ACL damage have OA-like features, most subjects (19 of 26, 73.1%) could be identified as in the early stage of OA. The prominent abnormalities present in ACL-damaged knees are cartilage defects, osteophytes, and meniscal abnormalities. (author)

  12. Possible linkage between neuronal recruitment and flight distance in migratory birds.

    Science.gov (United States)

    Barkan, Shay; Roll, Uri; Yom-Tov, Yoram; Wassenaar, Leonard I; Barnea, Anat

    2016-01-01

    New neuronal recruitment in an adult animal's brain is presumed to contribute to brain plasticity and increase the animal's ability to contend with new and changing environments. During long-distance migration, birds migrating greater distances are exposed to more diverse spatial information. Thus, we hypothesized that greater migration distance in birds would correlate with the recruitment of new neurons into the brain regions involved with migratory navigation. We tested this hypothesis on two Palearctic migrants - reed warblers (Acrocephalus scirpaceus) and turtle doves (Streptopelia turtur), caught in Israel while returning from Africa in spring and summer. Birds were injected with a neuronal birth marker and later inspected for new neurons in brain regions known to play a role in navigation - the hippocampus and nidopallium caudolateral. We calculated the migration distance of each individual by matching feather isotopic values (δ(2)H and δ(13)C) to winter base-maps of these isotopes in Africa. Our findings suggest a positive correlation between migration distance and new neuronal recruitment in two brain regions - the hippocampus in reed warblers and nidopallium caudolateral in turtle doves. This multidisciplinary approach provides new insights into the ability of the avian brain to adapt to different migration challenges. PMID:26905978

  13. Stress fractures of the humerus, radius, and tibia in horses: clinical features and radiographic and/or scintigraphic appearance

    International Nuclear Information System (INIS)

    The medical records, radiographic and nuclear scintigraphic findings of 26 racing horses with 27 stress fracture episodes of the humerus, radius, or tibia were reviewed. The purposes of this study were to describe the radiographic and/or scintigraphic features of stress fractures of the humerus, radius, or tibia, and to evaluate the signalment and history of horses in which stress fracture occurred. Stress fractures of the three long bones examined were primarily seen in 2- and 3-year-old male Thoroughbred horses; commonly, the onset of lameness was immediately following training gallops or racing. There were 13 humeral stress fracture episodes in 12 horses. Ten were in the proximal caudolateral cortex, and three were in the distal craniomedial cortex. Radical stress fractures were seen in three horses, all in the midshaft radius. Tibial stress fractures were diagnosed in 11 horses. They were located in the proximal lateral tibia in six horses, the distal caudolateral tibia in three horses, and the midshaft tibia in three horses. Fifteen stress fractures were diagnosed with radiography alone, one was diagnosed with scintigraphy alone, nine were diagnosed with radiographs and scintigraphy, and, in two horses, radiographs were negative, but the scintigraphic findings were consistent with stress fracture

  14. Sampling microcanonical ensembles of trajectories using harmonic approximation in internal coordinates.

    Science.gov (United States)

    Rybkin, Vladimir V; Ekström, Ulf

    2014-08-14

    In this paper, we modify quasiclassical harmonic sampling of microcanonical ensembles of trajectories by using the curvilinear internal coordinates. The harmonic approximation in the curvilinear normal coordinates provides a more realistic description of the PES than in the conventional rectilinear ones at finite displacements. Therefore, the sampling of vibrations in the internal coordinates significantly improves the quality of the sampling in a block-box fashion, providing more realistic displacements and reducing the errors in the potential energy. In particular, the sampling of large-amplitude torsion vibrations, which is non-realistic in the Cartesian modes, becomes accurate or acceptable in the curvilinear modes.

  15. Dysphagia due to anterior cervical osteophytosis: case report

    Directory of Open Access Journals (Sweden)

    Frederico Miguel Santos Silva Marquez Correia

    2014-12-01

    Full Text Available The objective of this study is to highlight the possibility of dysphagia induced by anterior cervical osteophytes. When not diagnosed early this condition may be responsible for complications such as severe dysphagia and potential lung aspiration, especially in elderly patients. Analysis of a case report of a 72-year old woman who presented cervical pain and progressive dysphagia. Imaging studies have shown anterior cervical osteophytosis and multilevel degenerative changes in the cervical spine. The patient underwent surgical excision of the cervical anterior osteophytes (C4, C5 and C6 and C5/C6 arthrodesis through anterior approach. The postoperative period was uneventful and symptoms resolved within 2 weeks. Early diagnosis and treatment led to complete resolution, avoiding late and serious complications associated with this pathology in the geriatric population, especially severe and progressive dysphagia and risk of pulmonary aspiration, and the consequent morbidity and mortality associated. A multidisciplinary approach is essential for the correct assessment of this condition

  16. The distribution and inter-relationships of radiologic features of osteoarthrosis of the hip. A survey of 4151 subjects of the Copenhagen City Heart Study: the Osteoarthrosis Substudy

    DEFF Research Database (Denmark)

    Jacobsen, Steffen; Sonne-Holm, Stig; Søballe, Kjeld;

    2004-01-01

    OBJECTIVE: The aims of this study were to investigate the influence of sex, age and individual physical and occupational factors on the distribution of radiographic features of hip joint osteoarthritis (OA), and to determine the inter-relationships between the primary radiographic OA discriminator......-relationships and correlations to age, sex, body mass index (BMI) and occupational exposure to repeated lifting. RESULTS: Overall, subchondral sclerosis, cysts and osteophytes were more frequently recorded in male hip joints compared to female hip joints, while a decrease in minimum JSW by age was more pronounced...... and progressive in women after the fifth decade compared to men. Applying logistic regression analyses, only age was found to be significantly associated to pathologically reduced minimum JSW (cut off value set at < or =2.0 mm), and the presence of osteophytes and subchondral cysts in both sexes (P...

  17. [Dysphagia: Forestier and Rotes Querol disease].

    Science.gov (United States)

    Cruz-Ruiz, M A; López-Saúz, M; Padierna-Luna, J L; García-Pescador, D; Franco-Grande, M A; Núñez-Sánchez, A

    2008-01-01

    Inside of the study of Dysphagia, until 38% of the greater patients of 50 years, they present/display cervical Osteophytes like cause of Dysphagia; frequently I diagnose passes for the methods of radiology and endoscopy unnoticed. The disease of Forestier and Rotes better well known Querol or like skeletal hiperostosis diffuse idiophatic it is characterized by the formation of spinal and cervical Osteophytes, ossification of ligaments and muscles for vetebrates of the cervical column. Frequently it produces affectation to medullar that it can pronounce like Dysphagia and crosstalk. We presented/displayed the case of a patient of 78 years with chronic pneumopathy, that presents/displays Dysphagia and progressive crosstalk with pondered loss, in where radiology of the cervical column they show cervical osteofitos with espondilolistesis, rectification of the cervical lordosis and diminution of the intersomatic spaces that they compress the trachea and column of air and an extrinsic compression below the cricopharyngeal is documented by endoscopy.

  18. Locking of metacarpophalangeal joints in a patient with acromegaly

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Y.; Tanaka, N.; Isoya, Eiji [Dept. of Orthopaedic Surgery, Soseikai General Hospital, Kyoto (Japan)

    1999-11-01

    A 39-year-old man with acromegaly exhibited locking of metacarpophalangeal (MCP) joints of both index fingers. Large osteophytes were found at the metacarpal heads by radiography and computerized tomography (CT). Magnetic resonance (MR) images revealed hypertrophy of volar plates. We suggest that these characteristic acromegalic features caused locking of MCP joints. Surgery was required on one of the joints to release the locking. (orig.)

  19. Cervical nerve root decompression by lateral approach as salvage operation after failed anterior transdiscal surgery: technical case report

    OpenAIRE

    Cornelius, Jan Frédérick; George, Bernard

    2009-01-01

    Cervical nerve root compression caused by disco-osteophytic changes is classically operated by anterior transdiscal approach with disc replacement. If compression persists or recurs, reoperation via the same surgical route may be difficult, because of scar tissue and/or implants. An alternative approach may be necessary. We recommend the lateral cervical approach (retrojugular) as salvage operation in such cases. We report a patient with cervical nerve root compression operated by anterior tr...

  20. Pterygoid hamulus bursitis as a cause of craniofacial pain: a case report

    OpenAIRE

    Cho, Jin-Yong; Cheon, Kang-Yong; Shin, Dong-Whan; Chun, Won-Bae; Lee, Ho

    2013-01-01

    Pain on the soft palate and pharynx can originate in several associated structures. Therefore, diagnosis of patients who complain of discomfort in these areas may be difficult and complicated. Pterygoid hamulus bursitis is a rare disease showing various symptoms in the palatal and pharyngeal regions. As such, it can be one of the reported causes of pain in these areas. Treatment of hamular bursitis is either conservative or surgical. If the etiologic factor of bursitis is osteophytic formatio...

  1. Update on anterior ankle impingement

    OpenAIRE

    Vaseenon, Tanawat; Amendola, Annunziato

    2012-01-01

    Anterior ankle impingement results from an impingement of the ankle joint by a soft tissue or osteophyte formation at the anterior aspect of the distal tibia and talar neck. It often occurs secondary to direct trauma (impaction force) or repetitive ankle dorsiflexion (repetitive impaction and traction force). Chronic ankle pain, swelling, and limitation of ankle dorsiflexion are common complaints. Imaging is valuable for diagnosis of the bony impingement but not for the soft tissue impingemen...

  2. The Effect of the PEEK Cage on the Cervical Lordosis in Patients Undergoing Anterior Cervical Discectomy

    Directory of Open Access Journals (Sweden)

    Salih Gulsen

    2015-03-01

    CONCLUSION: We achieved better cervical lordotic angles at the postoperative period by implanting one-level, two-level, three-level or four-level PEEK cage filled with demineralized bone matrix. Also, the causes of cervical root and or medulla spinalis impingement were different in group1 and 2. While extruded cervical disc impingement was the first pathology in group 1, osteophyte formation was the first pathology in group 2.

  3. Low back pain and degenerative disc disease

    OpenAIRE

    Jandrić Slavica; Antić Branislav

    2006-01-01

    Introduction. Various clinical conditions can cause low back pain, and in most cases it is of a degenerative origin. Degenerative disc disease is a common condition which affects young to middle-aged men and women equally. Changes in the mechanical properties of the disc lead to degenerative arthritis in the intervertebral joints, osteophytes, and narrowing the intervertebral foramen or the spinal canal. Pathophysiology. Degenerative cascade, described by Kirkaldy-Willis, is the widely accept...

  4. Radiographic changes of lumbar spine and pelvis in chronic spinal injury

    Directory of Open Access Journals (Sweden)

    Shamsa Shariatpanahi

    2014-12-01

    Conclusion: The most frequent cause of chronic spinal injuries of our patients has been the injury by quiver, it seems our results may not be extended to all patients with spinal cord injury. In lumbar spine radiography of the patients, osteophytes, the quiver and psoriasis like ossifications were mostly seen. In the pelvis x-rays the most changes were hip joint narrowing, sacroiliitis and the heterotopic ossification.

  5. Differentiation between Symptomatic and Asymptomatic Extraforaminal Stenosis in Lumbosacral Transitional Vertebra: Role of Three-Dimensional Magnetic Resonance Lumbosacral Radiculography

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Woo Mok; Kim, Jae Woon; Lee, Jae Kyo [Yeungnam University College of Medicine, Daegu (Korea, Republic of)

    2012-07-15

    To investigate the role of lumbosacral radiculography using 3-dimentional (3D) magnetic resonance (MR) rendering for diagnostic information of symptomatic extraforaminal stenosis in lumbosacral transitional vertebra. The study population consisted of 18 patients with symptomatic (n = 10) and asymptomatic extraforaminal stenosis (n = 8) in lumbosacral transitional vertebra. Each patient underwent 3D coronal fast-field echo sequences with selective water excitation using the principles of the selective excitation technique (Proset imaging). Morphologic changes of the L5 nerve roots at the symptomatic and asymptomatic extraforaminal stenosis were evaluated on 3D MR rendered images of the lumbosacral spine. Ten cases with symptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. On 3D MR lumbosacral radiculography, indentation of the L5 nerve roots was found in two cases, while swelling of the nerve roots was seen in eight cases at the exiting nerve root. Eight cases with asymptomatic extraforaminal stenosis showed hyperplasia and degenerative osteophytes of the sacral ala and/or osteophytes at the lateral margin of the L5 body. Based on 3D MR lumbosacral radiculography, indentation or swelling of the L5 nerve roots was not found in any cases with asymptomatic extraforaminal stenosis. Results from 3D MR lumbosacral radiculography Indicate the indentation or swelling of the L5 nerve root in symptomatic extraforaminal stenosis. Based on these findings, 3D MR radiculography may be helpful in the diagnosis of the symptomatic extraforaminal stenosis with lumbosacral transitional vertebra.

  6. Appendicular bone mass and knee and hand osteoarthritis in Japanese women: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Moji Kazuhiko

    2002-10-01

    Full Text Available Abstract Background It has been reported that there is an inverse association between osteoarthritis (OA and osteoporosis. However, the relationship of bone mass to OA in a Japanese population whose rates of OA are different from Caucasians remains uncertain. Methods We studied the association of appendicular bone mineral density (second metacarpal; mBMD and quantitative bone ultrasound (calcaneus; stiffness index with knee and hand OA among 567 Japanese community-dwelling women. Knee and hand radiographs were scored for OA using Kellgren-Lawrence (K/L scales. In addition, we evaluated the presence of osteophytes and of joint space narrowing. The hand joints were examined at the distal and proximal interphalangeal (DIP, PIP and first metacarpophalangeal/carpometacarpal (MCP/CMC joints. Results After adjusting for age and body mass index (BMI, stiffness index was significantly higher in women with K/L scale, grade 3 at CMC/MCP joint compared with those with no OA. Adjusted means of stiffness index and mBMD were significantly higher in women with definite osteophytes at the CMC/MCP joint compared to those without osteophytes, whereas there were no significant differences for knee, DIP and PIP joints. Stiffness index, but not mBMD, was higher in women with definite joint space narrowing at the CMC/MCP joint compared with those with no joint space narrowing. Conclusions Appendicular bone mass was increased with OA at the CMC/MCP joint, especially among women with osteophytes. Our findings suggest that the association of peripheral bone mass with OA for knee, DIP or PIP may be less clearcut in Japanese women than in other populations.

  7. Vertebral Fractures and Spondylosis in Men - Original Investigation

    Directory of Open Access Journals (Sweden)

    Selmin Gülbahar

    2008-04-01

    Full Text Available Aim: The aim of this study was to investigate the relationship between vertebral fractures and spondylosis and bone mineral density in men older than 60 years. Material and Method: Thirty-two men with back and low back pain aged over 60 years were included into the study. Thoracic and lumbar spine radiographs were taken and, anterior, central and posterior heights of each vertebral body from T4 to L5 was measured and than the number of vertebral fractures was assessed. Osteophyte and disc scores were used for evaluation of spondylosis. Bone mineral density was measured by dual-energy-X-ray absorptiometry. Measurements were obtained from lumbar vertebrae and proximal femoral region. Results: Significant positive correlations were found between vertebral fracture and osteophyte score and bone mineral density of total femoral region. When osteophyte score and total femoral bone mineral density were taken into consideration, there were no significant correlations between other parameters and vertebral fracture. Significant positive correlations were observed between osteophyte score and bone mineral density and t scores of L1-4. Also there were significant positive correlations between disc score and both bone mineral density and t scores of L1-4. Significant positive correlation was also found between femoral bone density and body weight. Conclusion: Finally, lumbar bone mineral density increases with spinal degenerative changes, but the increase in bone mineral density can not prevent sub clinic vertebral fractures. Especially, in the men who have intensive spinal degenerative changes, the measurement of lumbar bone mineral density is not enough for determining the fracture risk. Measurement of femoral bone mineral density and evaluation of clinic risk factors are more important for determining the fracture risk. (From the World of Osteoporosis 2008;14:1-6

  8. NUMERICAL SOLUTION FOR TIDAL FLOW IN OPENING CHANNEL USING COMBINED MACCORMACK - FINITE ANALYSIS METHOD

    Institute of Scientific and Technical Information of China (English)

    WU Zhao-chun; WANG Dao-zeng

    2009-01-01

    e computational results agree with the measured data. By use of orthogonal curvilinear coordinate system, the methods can be easily extended to the numerical simulation of the tidal flow in a tortuous channel.

  9. Capsulorhexis contraction after cataract surgery

    DEFF Research Database (Denmark)

    Corydon, Charlotte; Lindholt, Michael; Knudsen, Ellen B;

    2007-01-01

    PURPOSE: To evaluate the reduction in the anterior capsule opening after phacoemulsification, continuous curvilinear capsulorhexis, and implantation of 1 of 2 acrylic intraocular lenses (IOLs). SETTING: Department of Ophthalmology, Vejle Hospital, Vejle, Denmark. METHODS: Eighty-four patients (84...

  10. Calcified congenital aneurysm of the left sinus of Valsalva associated with coarctation of the aorta

    International Nuclear Information System (INIS)

    A case of calcified unruptured congenital aneurysm of the left sinus of Valsalva associated with coarctation of the aorta is presented. Routine chest radiographs demonstrated unusual curvilinear calcifications at the cardiac base which were subsequently demonstrated within the aneurysm. (orig.)

  11. Major Breakthrough in Pipeline Crossing

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    @@ Based on 10 years of concentrated study, the scientific and technical personnel of No. 2 oil field Construction Company of Liaohe Oil Field succeeded its river-crossing technique for curvilinear push pipe on March 10,1997.

  12. THE CHOICE OF A RATIONAL STRUCTURAL DESIGN OF ELECTRODYNAMIC TRANSPORT SYSTEMS

    Directory of Open Access Journals (Sweden)

    M. O. Radchenko

    2009-03-01

    Full Text Available The design schemes of electrodynamic maglev systems with a plane track structure are developed and the results of investigation of levitating motion of such systems along rectilinear or curvilinear tracks are presented.

  13. Some shell formulations, in view of their applicability to finite elements

    OpenAIRE

    Debongnie, Jean-François

    1986-01-01

    Surface geometry and shell geometry, in the frame of general tensor calculus. Fundamentals of the theory of thin shells. Expressing strains from curvilinear components of the displacements. Applicability of the preceeding theory to finite elements. Expressing strains from the cartesian components of the displacements. Moderate rotation theory (curvilinear components). Moderate rotation theory (cartesian components). Quasi-plane and almost-plane shells. Shells with shearing strains (cartesian ...

  14. Emotional and Physiological Desensitization to Real-Life and Movie Violence

    OpenAIRE

    Mrug, Sylvie; Madan, Anjana; Cook, Edwin W.; Wright, Rex A.

    2014-01-01

    Youth are exposed to large amounts of violence in real life and media, which may lead to desensitization. Given evidence of curvilinear associations between exposure to violence and emotional distress, we examined linear and curvilinear associations of exposure to real-life and movie violence with PTSD symptoms, empathy, and physiological arousal, as well emotional and physiological reactivity to movie violence. College students (N=209; mean age=18.74) reported on their exposure to real-life ...

  15. Hybrid Finite Element and Volume Integral Methods for Scattering Using Parametric Geometry

    DEFF Research Database (Denmark)

    Volakis, John L.; Sertel, Kubilay; Jørgensen, Erik;

    2004-01-01

    n this paper we address several topics relating to the development and implementation of volume integral and hybrid finite element methods for electromagnetic modeling. Comparisons of volume integral equation formulations with the finite element-boundary integral method are given in terms of...... accuracy and computing resources. We also discuss preconditioning and parallelization of the multilevel fast multipole method, and propose higher-order basis functions for curvilinear quadrilaterals and volumetric basis functions for curvilinear hexahedra. The latter have the desirable property of...

  16. 反変速度-圧力交互時間進行による一般曲線座標系FDTD音場解析手法

    OpenAIRE

    大嶋, 拓也; Oshima, Takuya

    2006-01-01

    Finite-difference time-domain (FDTD) acoustic simulation technique in generalized curvilinear coordinates using contravariant velocity and pressure as variables for two-step leapfrog time marching scheme is presented. The technique excels the conventional generalized curvilinear technique using contravariant velocity, covariant velocity and pressure as variables for three-step time marching, especially in that normal acoustic impedance boundary conditions which are indispensable in practical ...

  17. 直交曲線座標における応力場について

    OpenAIRE

    奥村, 勇; I., Okumura

    2000-01-01

    Stress and strain tensors, the equilibrium equation in terms of the stress tensor and transformation laws for the tensors, in orthogonal curvilinear coordinates, are presented. The components of the tensor are defined as covariant components of second-order tensors, which are identical to stress and strain components. The invariants of stress and strain, and the principal stress and strains in the orthogonal curvilinear coordinates are obtained from characteristic polynomials and eigenvalues...

  18. Large Eddy Simulation of Turbulent Combustion with Chemical Kinetics

    OpenAIRE

    Panjwani, Balram

    2011-01-01

    The present doctoral thesis studies and develops methodologies for turbulent combustion with the Large Eddy Simulation (LES). Three main objectives for present doctoral thesis were.First, development of LES methodology in curvilinear coordinates. LES formulation in curvilinear coordinates can be achieved in two ways, (1) conventional approach, where filtering is performed prior to the transformation, and (2) alternate approach, where filtering is performed after the transformation. In present...

  19. Multidisciplinary Optimization and Damage Tolerance of Stiffened Structures

    OpenAIRE

    Jrad, Mohamed

    2015-01-01

    The structural optimization of a cantilever aircraft wing with curvilinear spars and ribs and stiffeners is described. The design concept of reinforcing the wing structure using curvilinear stiffening members has been explored due to the development of novel manufacturing technologies like electron-beam-free-form-fabrication (EBF3). For the optimization of a complex wing, a common strategy is to divide the optimization procedure into two subsystems: the global wing optimization which optimize...

  20. A Note on Natural Coordinates and Frenet Frames

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiaozhou; ZHU Keqin

    2007-01-01

    This paper discusses the relationship between natural coordinates in fluid mechanics and orthogonal curvilinear coordinates. Since orthogonal curvilinear coordinates have some excellent mathematical properties, natural coordinates can be applied more widely if they can be transformed to orthogonal curvilinear coordinates. Frenet formulas which describe the differential properties of natural coordinates were compared with the derivative formulas of orthogonal curvilinear coordinates to show that natural coordinates are not generally orthogonal curvilinear coordinates. A method was introduced to transform natural coordinates into orthogonal curvilinear coordinates by rotating the normal planes of the natural coordinates about the streamlines. The transformation is true as long as the natural coordinates satisfy several equations. Vorticity decomposition in the natural coordinates is used to show that these conditional equations are satisfied only if the streamlines are perpendicular to the vortexlines on every given point in the flow field. These equations apply in both planar flows and axisymmetric flows without a circumferential velocity component, but do not apply in some 3-D flows such as Beltrami flow.

  1. The Neural Basis of Long-Distance Navigation in Birds.

    Science.gov (United States)

    Mouritsen, Henrik; Heyers, Dominik; Güntürkün, Onur

    2016-01-01

    Migratory birds can navigate over tens of thousands of kilometers with an accuracy unobtainable for human navigators. To do so, they use their brains. In this review, we address how birds sense navigation- and orientation-relevant cues and where in their brains each individual cue is processed. When little is currently known, we make educated predictions as to which brain regions could be involved. We ask where and how multisensory navigational information is integrated and suggest that the hippocampus could interact with structures that represent maps and compass information to compute and constantly control navigational goals and directions. We also suggest that the caudolateral nidopallium could be involved in weighing conflicting pieces of information against each other, making decisions, and helping the animal respond to unexpected situations. Considering the gaps in current knowledge, some of our suggestions may be wrong. However, our main aim is to stimulate further research in this fascinating field. PMID:26527184

  2. The Neural Basis of Long-Distance Navigation in Birds.

    Science.gov (United States)

    Mouritsen, Henrik; Heyers, Dominik; Güntürkün, Onur

    2016-01-01

    Migratory birds can navigate over tens of thousands of kilometers with an accuracy unobtainable for human navigators. To do so, they use their brains. In this review, we address how birds sense navigation- and orientation-relevant cues and where in their brains each individual cue is processed. When little is currently known, we make educated predictions as to which brain regions could be involved. We ask where and how multisensory navigational information is integrated and suggest that the hippocampus could interact with structures that represent maps and compass information to compute and constantly control navigational goals and directions. We also suggest that the caudolateral nidopallium could be involved in weighing conflicting pieces of information against each other, making decisions, and helping the animal respond to unexpected situations. Considering the gaps in current knowledge, some of our suggestions may be wrong. However, our main aim is to stimulate further research in this fascinating field.

  3. Fat-Free Body Mass but not Fat Mass is Associated with Reduced Gray Matter Volume of Cortical Brain Regions Implicated in Autonomic and Homeostatic Regulation

    Science.gov (United States)

    Weise, Christopher M; Thiyyagura, Pradeep; Reiman, Eric M; Chen, Kewei; Krakoff, Jonathan

    2014-01-01

    Obesity has been associated with alterations of both functional and structural aspects of the human central nervous system. In obese individuals both fat mass (FM; primarily consisting of adipose tissue) and fat-free mass (FFM; all non-adipose tissues) are increased and it remains unknown whether these compartments have separate effects on human brain morphology. We used voxel-based morphometry to investigate the relationships between measures of body composition and regional gray matter volume (GMV) in 76 healthy adults with a wide range of adiposity (24F/52M; age 32.1±8.8y; percentage of body fat [PFAT%] 25.5±10.9%; BMI 29.8±8.9). Faf-free mass index (FFMI kg*m-2) showed negative associations in bilateral temporal regions, the bilateral medial and caudolateral OFC, and the left insula. Fat mass index (FMI kg*m-2) showed similar, but less extensive negative associations within temporal cortical regions and the left caudolateral orbitofrontal cortex (OFC). In addition, negative associations were seen for FMI with GMV of the cerebellum. Associations of FFMI with temporal and medial orbitofrontal GMV appeared to be independent of adiposity. No associations were seen between measures of adiposity (i.e. FM and PFAT) and GMV when adjusted for FFM. The majority of regions that we find associated with FFM have been implicated in the regulation of eating behavior and show extensive projections to central autonomic and homeostatic core structures. These data indicate that not adipose tissue or relative adiposity itself, but obesity related increases in absolute tissue mass and particularly FFM may have a more predominant effect on the human brain. This might be explained by the high metabolic demand of FFM and related increases in total energy needs. PMID:22974975

  4. Two Single-Nucleotide Polymorphisms in ADAM12 Gene Are Associated with Early and Late Radiographic Knee Osteoarthritis in Estonian Population.

    Science.gov (United States)

    Kerna, Irina; Kisand, Kalle; Tamm, Ann E; Kumm, Jaanika; Tamm, Agu O

    2013-01-01

    Objectives. To investigate associations of selected single-nucleotide polymorphisms (SNPs) in ADAM12 gene with radiographic knee osteoarthritis (rKOA) in Estonian population. Methods. The rs3740199, rs1871054, rs1278279, and rs1044122 SNPs in ADAM12 gene were genotyped in 438 subjects (303 women) from population-based cohort, aged 32 to 57 (mean 45.4). The rKOA features were evaluated in the tibiofemoral joint (TFJ) and patellofemoral joint. Results. The early rKOA was found in 51.4% of investigated subjects (72% women) and 12.3% of participants (63% women) had advanced stage of diseases. The A allele of synonymous SNP rs1044122 was associated with early rKOA in TFJ, predominantly with the presence of osteophytes in females (OR 1.57; 95% CI 1.08-2.29, P = 0.018). The C allele of intron polymorphism rs1871054 carried risk for advanced rKOA, mostly to osteophyte formation in TFJ in males (OR 3.03; 95% CI 1.11-7.53, P = 0.018). Also the CCAA haplotype of ADAM12 was associated with osteophytosis, again mostly in TFJ in males (P = 0.014). For rs3740199 and rs1278279, no statistically significant associations were observed. Conclusion.  ADAM12 gene variants are related to rKOA risk during the early and late stages of diseases. The genetic risk seems to be predominantly associated with the appearance of osteophytes-a marker of bone remodelling and neochondrogenesis.

  5. Cervical disc hernia operations through posterior laminoforaminotomy

    Directory of Open Access Journals (Sweden)

    Coskun Yolas

    2016-01-01

    Full Text Available Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years. Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%. On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  6. Agreement in the Interpretation of Magnetic Resonance Images of the Lumbar Spine

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, F.M. (Dept. Cientfico, Fundacin Kovacs, Palma de Majorca (Spain)); Royuela, A. (Spanish Back Pain Research Network, Fundacin Kovacs, Palma de Majorca (Spain)); Jensen, T.S. (Back Research Center, Backcenter Funen, Ringe (Denmark)) (and others)

    2009-06-15

    Background: Correlation between clinical features and magnetic resonance imaging (MRI) findings is essential in low-back-pain patients. Most previous studies have analyzed concordance in the interpretation of lumbar MRI among a few radiologists who worked together. This may have overestimated concordance. Purpose: To evaluate intra- and interobserver agreement in the interpretation of lumbar MRI performed in an open 0.2T system. Material and Methods: Seven radiologists from two different geographic settings in Spain interpreted the lumbar MRIs of 50 subjects representative of the general Danish population aged 40 years. The radiologists interpreted the images in routine clinical practice, having no knowledge of the clinical and demographic characteristics of the subjects and blinded to their colleagues' assessments. Six of the radiologists evaluated the same MRIs 14 days later, having no knowledge of the previous results. Data on the existence of disc degeneration, high-intensity zones, disc contour, Schmorl nodes, Modic changes, osteophytes, spondylolisthesis, and spinal stenosis were collected in the Nordic Modic Consensus Group Classification form. Intra- and interobserver agreement was analyzed for variables with a prevalence =10% and =90% by means of the kappa statistic. Results: Intra- and interobserver agreement was excellent for variables related to Modic changes, and fair to good for disc contour, high-intensity zones, and Schmorl nodes. The evaluations for disc degeneration and osteophytes were found to have fair to good intraobserver agreement and poor interobserver agreement. The agreement for the evaluations of spondylolisthesis and spinal stenosis was not analyzed because they were observed in <10% of reports. Conclusion: Images from 0.2T MRIs appear to lead to good agreement in the reporting of disc contour, high-intensity zones, Schmorl nodes, and, in particular, Modic changes, suggesting that they can possibly be reliably used for clinical

  7. MR appearance of autologous chondrocyte implantation in the knee: correlation with the knee features and clinical outcome

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Tomoki [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Kumamoto University, Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Kumamoto (Japan); Tins, Bernhard; McCall, Iain W.; Ashton, Karen [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Trust, Department of Diagnostic Imaging, Oswestry, Shropshire (United Kingdom); Richardson, James B. [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); RJAH Orthopaedic Hospital, Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Takagi, Katsumasa [Department of Radiology and Institute of Orthopaedics, Oswestry, Shropshire (United Kingdom); Kumamoto Aging Research Institute, Kumamoto (Japan)

    2006-01-01

    To relate the magnetic resonance imaging (MRI) appearance of autologous chondrocyte implantation (ACI) in the knee in the 1st postoperative year with other knee features on MRI and with clinical outcome. Forty-nine examinations were performed in 49 patients at 1 year after ACI in the knee. Forty-one preoperative magnetic resonance (MR) examinations were also available. The grafts were assessed for smoothness, thickness in comparison with that of adjacent cartilage, signal intensity, integration to underlying bone and adjacent cartilage, and congruity of subchondral bone. Presence of overgrowth and bone marrow appearance beneath the graft were also assessed. Presence of osteophyte formation, further cartilage defects, appearance of the cruciate ligaments and the menisci were also recorded. An overall graft score was constructed, using the graft appearances. This was correlated with the knee features and the Lysholm score, a clinical self-assessment score. The data were analysed by a Kruskal-Wallis H test followed by a Mann-Whitney U test with Bonferroni correction as post-hoc test. Of 49 grafts, 32 (65%) demonstrated complete defect filling 1 year postoperatively. General overgrowth was seen in eight grafts (16%), and partial overgrowth in 13 grafts (26%). Bone marrow change underneath the graft was seen; oedema was seen in 23 grafts (47%), cysts in six grafts (12%) and sclerosis in two grafts (4%). Mean graft score was 8.7 (of maximal 12) (95% CI 8.0-9.5). Knees without osteophyte formation or additional other cartilage defects (other than the graft site) had a significantly higher graft score than knees with multiple osteophytes (P=0.0057) or multiple further cartilage defects (P=0.014). At 1 year follow-up improvement in the clinical scores was not significantly different for any subgroup. (orig.)

  8. Optimal embedding for shape indexing in medical image databases.

    Science.gov (United States)

    Qian, Xiaoning; Tagare, Hemant D; Fulbright, Robert K; Long, Rodney; Antani, Sameer

    2010-06-01

    This paper addresses the problem of indexing shapes in medical image databases. Shapes of organs are often indicative of disease, making shape similarity queries important in medical image databases. Mathematically, shapes with landmarks belong to shape spaces which are curved manifolds with a well defined metric. The challenge in shape indexing is to index data in such curved spaces. One natural indexing scheme is to use metric trees, but metric trees are prone to inefficiency. This paper proposes a more efficient alternative. We show that it is possible to optimally embed finite sets of shapes in shape space into a Euclidean space. After embedding, classical coordinate-based trees can be used for efficient shape retrieval. The embedding proposed in the paper is optimal in the sense that it least distorts the partial Procrustes shape distance. The proposed indexing technique is used to retrieve images by vertebral shape from the NHANES II database of cervical and lumbar spine X-ray images maintained at the National Library of Medicine. Vertebral shape strongly correlates with the presence of osteophytes, and shape similarity retrieval is proposed as a tool for retrieval by osteophyte presence and severity. Experimental results included in the paper evaluate (1) the usefulness of shape similarity as a proxy for osteophytes, (2) the computational and disk access efficiency of the new indexing scheme, (3) the relative performance of indexing with embedding to the performance of indexing without embedding, and (4) the computational cost of indexing using the proposed embedding versus the cost of an alternate embedding. The experimental results clearly show the relevance of shape indexing and the advantage of using the proposed embedding.

  9. Significance of arthrosonography for knee joint damage diagnosis in patients with early rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    L V Sizova

    2008-01-01

    Full Text Available Objective. To assess significance of arthrosonography in diagnosis of in knee joint changes in patients with early rheumatoid arthritis (RA. Material and methods. 44 patients with early RA aged 19 to 73 years were examined. 29,5% of pts had early RA without primary osteoarthritis (OA, 70,5% had early RA with primary OA. Ultrasonography of knee joints was performed with Diasonics (USA, 1997 by the linear sensor with frequency of 7 MHz. The protocol of ultrasonic examination of knee joints was filled for each pt. Results. Clinical signs of of knee joint synovitis have been revealed in 61,5% of pts with early RA without primary OA, and in 80,6% of pts with early RA with primary OA, ultrasonic - in 100% of pts. Intraarticular knee joint effusion resulted in increase of suprapatellar bursa and lateral recesses size. Extraarticular inflammation was frequently shown by thickening of semymemranous muscles tendons, especially in pts with the early RA with primary OA (p<0,005. Degenerative changes in the group of pts with primary OA were more expressed in early RA and usually accompanied by non-uniform decrease of cartilage thickness and occurrence of osteophytes while cartilage in pts with early RA without primary OA had normal thickness or thickening because of swelling, and osteophytes were absent. Conclusion. Prevalence of knee joint intraarticular and extraarticular inflammatory changes over degenerate changes (symmetric thickening of the synovium, primary increase of the sizes of suprapatellar bursa and lateral recesses because of effusion, thickening of tendons of knee joints at the normal or increased thickness of cartilage because of inflammation can be considered sonographic sign of early RA. In pts with early RA coincided with primary OA these changes were usually found in combination with non-uniform decrease of cartilage thickness. In case of cartilage inflammatory edema, detection of osteophytes allows to confirm presence of OA in pts with

  10. Childhood interparental conflict and HPA axis activity in young adulthood: examining nonlinear relations.

    Science.gov (United States)

    Hagan, Melissa J; Roubinov, Danielle S; Purdom Marreiro, Catherine L; Luecken, Linda J

    2014-05-01

    Relations between early adversity and the neuroendocrine stress response are most often tested in a linear framework. Findings from studies of nonlinear relations between early stress and reactivity in childhood are suggestive, but curvilinear associations between childhood family stress and stress reactivity at later developmental stages remain unexplored. The current study examined curvilinear relations between childhood interparental conflict (IPC) and cortisol reactivity in young adulthood. Participants (n = 91; Mean age = 18.7, SD = .97; 59% White, 25% Hispanic) reported on the frequency and intensity of childhood exposure to IPC and salivary cortisol was sampled before and after a challenging interpersonal role-play task. Significant curvilinear relations were found such that higher total cortisol and cortisol reactivity during the task was observed among youth reporting lower and higher frequency of IPC, suggesting that moderate IPC exposure may be associated with lower cortisol activity at a later developmental stage.

  11. Hip dysplasia in a litter of Domestic Shorthair cats

    International Nuclear Information System (INIS)

    A 14-month-old female Domestic Shorthair cat was presented with bilaterally shallow acetabuli, flattened femoral heads, and subluxation of the hips, changes consistent with hip dysplasia. Follow-up radiographs showed additional osteophyte formation and remodeling of both coxofemoral joints. Two of her female littermate exhibited the same condition. Pelvic examinations of a male from the same litter as well as those of the queen and two other 3-year-old offspring were normal. This report demonstrates that it is likely that genetics plays a role in felinehip dysplasia, although further detailed reports and similar investigations of related cats affected by this condition are needed

  12. Macrodystrophia Lipomatosa of the Toe: A Rare Case Report

    Science.gov (United States)

    Durairaj, Alagar Raja

    2016-01-01

    Macrodystrophia lipomatosa is a rare congenital hamartoma presenting as a localized or generalized gigantism of a limb or digit manifesting from infancy to late adulthood. It is a progressive enlargement of the soft tissue components, especially fibrofatty tissue. The patient presents to us because of cosmetic reasons or mechanical issues secondary to degenerative joint disease, or features of neurovascular compression due to large osteophytes. Here, we present a case of this anomaly of the left second toe with complaints of difficulty in walking and wearing shoes, for which toe reduction surgery with partial amputation was done. PMID:27190893

  13. Cross-sectional association between urinary type II collagen. C-terminal telopeptide concentration and radiographic spinal disc degeneration

    International Nuclear Information System (INIS)

    When degraded, type II collagen, which is contained in large quantities in the cartilage and intervertebral discs, produces a C-terminal peptide (type II collagen C terminal telopeptide, CTX-II), which is excreted in the urine. It has been reported that CTX-II is useful for evaluating the severity of cartilage degeneration and abrasion in the hip and knee joints, but shows no correlation with the severity of degeneration of intervertebral discs, which are mostly composed of type II collagen. The present study was performed to clarify whether urinary CTX-II was correlated with intervertebral X-ray findings. A cross-sectional study was performed to clarify correlations between urinary CTX-II and the progression of degeneration of each intervertebral disc on lumbar X-P films. The subjects of this study were 100 patients (400 intervertebral discs) aged≥40 years. They visited this hospital for the first time because of low backache. Intervertebral disc height, osteophyte length and Kellgren-Lawrence classification were measured to evaluate the degree of lumbar disc degeneration on X-ray films. The second freshly voided urine was used for measuring urinary CTX-II. The measurement results were investigated for correlations with disc height, osteophyte length, age, sex, body mass index (BMI), and lumbar MRI findings by cross-sectional analysis. The t-test and Kruskal-Wallis-test were used for statistical analysis of data. Urinary CTX-II was not correlated with age or BMI but was significantly higher in females than in males. It was only correlated with the degeneration of L2/3 and 3/4 discs and showed a significant difference between lower, medium, and higher disc groups. It was not correlated with osteophyte length or lumbar MRI findings. Urinary CTX-II was only correlated with L2/3 and 3/4 disc degeneration. This was presumably ascribable to the focus and distance during radiography. Osteophyte formation is a phenomenon secondary to intervertebral disc degeneration

  14. Combined spinal–epidural anesthesia for an elderly patient with proportionate dwarfism for laparotomy

    Directory of Open Access Journals (Sweden)

    Teena Bansal

    2016-01-01

    Full Text Available Anesthesia in a dwarf patient may be challenging as various anatomical anomalies make both general and regional anesthesia difficult. These patients may have atlantoaxial instability, potential for airway obstruction, and associated respiratory problems that may pose problems for general anesthesia. Spinal stenosis, osteophytes, short pedicles, or a small epidural space could complicate regional anesthesia in dwarfs which could lead to difficulties in locating the epidural space and increase the risk of dural puncture. Spinal stenosis may impair cerebrospinal fluid flow such that identification of dural puncture is difficult. This elderly dwarf patient had history of bronchial asthma with restriction of neck extension, managed successfully using combined spinal–epidural anesthesia.

  15. Effects of strontium ranelate on spinal osteoarthritis progression

    DEFF Research Database (Denmark)

    Bruyere, O; Delferriere, D; Roux, C;

    2008-01-01

    Peripheral OSteoporosis (TROPOS) trials performed on 1105 women with osteoporosis and concomitant radiological spinal OA at baseline, and for whom lumbar x-rays were available at baseline and over the 3-year treatment period. The presence and severity of osteophytes, disc space narrowing and sclerosis in the...... lumbar intervertebral spaces was graded according to a validated method, and an overall OA score was calculated for each intervertebral space. Back pain (measured on a five-point Likert scale only in SOTI) and health-related quality of life (SF-36 questionnaire) were assessed at baseline and after 3...

  16. A diagnostic and therapeutic challenge involving a case of dysphagia in association with cervical osteophytosis and a dental pain

    Science.gov (United States)

    Dable, Rajani A.; Wasnik, Pradnya B.; Nagmode, Sunilkumar L.; Ali, Mukkaram Faridi

    2013-01-01

    Herein, presenting a case of a 42-year-old female with the chief complaint of dysphagia. The problem was assumed to be of dental origin, due to the onset of dental pain followed by dysphagia. A cervical radiograph revealed the presence of osteophytic lipping which proved to be the cause of dysphagia. Confusing and overlapping disease entities showing similar symptoms need thorough investigation. Dysphagia related to cervical spondylosis may have a direct connection with the person's occupation. Dentistry is considered a potentially hazardous occupation with regard to musculoskeletal disorders. However, additional studies are required to understand the occupational hazards faced by dentists. PMID:24250178

  17. A diagnostic and therapeutic challenge involving a case of dysphagia in association with cervical osteophytosis and a dental pain

    Directory of Open Access Journals (Sweden)

    Rajani A Dable

    2013-01-01

    Full Text Available Herein, presenting a case of a 42-year-old female with the chief complaint of dysphagia. The problem was assumed to be of dental origin, due to the onset of dental pain followed by dysphagia. A cervical radiograph revealed the presence of osteophytic lipping which proved to be the cause of dysphagia. Confusing and overlapping disease entities showing similar symptoms need thorough investigation. Dysphagia related to cervical spondylosis may have a direct connection with the person′s occupation. Dentistry is considered a potentially hazardous occupation with regard to musculoskeletal disorders. However, additional studies are required to understand the occupational hazards faced by dentists.

  18. Is orthopantomography reliable for TMJ diagnosis? An experimental study on a dry skull.

    Science.gov (United States)

    Ruf, S; Pancherz, H

    1995-01-01

    The accuracy of orthopantomography in reproducing the temporomandibular joint area was analyzed on a dry skull. The results based on this study of a single skull revealed that the radiographic image of the temporomandibular joint did not correspond to the anatomic condylar and fossa components or to their actual relationship. To a large extent, changes in skull position affected the radiographic temporomandibular joint image, simulating anterior condylar flattening, osteophytes, narrowing of joint space, and left/right condylar asymmetry. Orthopantomography may have questionable reliability for temporomandibular joint diagnostic purposes.

  19. 以咽异物感为表现的食管型颈椎病1例%One cases of esophageal cervical spondylosis with pharyngeal foreign body sensation

    Institute of Scientific and Technical Information of China (English)

    齐志勇; 张治平; 呼和牧仁; 鄂建新

    2012-01-01

    The patient was treated as pharyngeal foreign body sensation for six months. Laryngeal endosco-pys one about 1 cmX2 cmX2 cm,hard.smooth bulge in hypopharyngeal wall at the plane of epiglottis valley. The cervical MRI showed that the C3-C4 disc herniation and degeneration of the C3-C4 vertebrae. Cervical CT showed the C3-C4 disc osteophyte formation and forward bulge. After orthopedic consultation, the patient was diagnosed as esophageal cervical spondylosis. C3-C4 diskectomy and vertebral interbody bone grafted with plate fixation were undertaken. At postoperational day 2, the pharyngeal foreign body sensation disappeared.

  20. SOLITARY EPIPHYSEAL PEDUNCULATED OSTEOCHONDROMA WITH SECONDARY OSTEOARTHRITIS: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar

    2015-04-01

    Full Text Available Osteochondroma is the relatively common bone tumor arising from the metaphysis of long bones . Osteochondroma arising from epiphysis of long bones are very rare . We report a case of a 67 year old man with history of right shoulder pain for past 5 years and difficulty in moving the arm for past 1 year . X - ray showed severe osteophytic changes and a subtle bony outgrowth from head of humerus . MRI showed cartilage capped bony outgrowth arising from the epiphysis of humerus . Medullary cavity of the lesion is seen communicating with the medullary cavity of bone consistent with osteochondroma .

  1. Macrodystrophia Lipomatosa of the Toe: A Rare Case Report.

    Science.gov (United States)

    Durairaj, Alagar Raja; Mahipathy, Surya Rao Rao Venkata

    2016-04-01

    Macrodystrophia lipomatosa is a rare congenital hamartoma presenting as a localized or generalized gigantism of a limb or digit manifesting from infancy to late adulthood. It is a progressive enlargement of the soft tissue components, especially fibrofatty tissue. The patient presents to us because of cosmetic reasons or mechanical issues secondary to degenerative joint disease, or features of neurovascular compression due to large osteophytes. Here, we present a case of this anomaly of the left second toe with complaints of difficulty in walking and wearing shoes, for which toe reduction surgery with partial amputation was done. PMID:27190893

  2. SMAD3 is associated with the total burden of radiographic osteoarthritis: the Chingford study.

    Directory of Open Access Journals (Sweden)

    Erfan Aref-Eshghi

    Full Text Available BACKGROUND: A newly-described syndrome called Aneurysm-Osteoarthritis Syndrome (AOS was recently reported. AOS presents with early onset osteoarthritis (OA in multiple joints, together with aneurysms in major arteries, and is caused by rare mutations in SMAD3. Because of the similarity of AOS to idiopathic generalized OA (GOA, we hypothesized that SMAD3 is also associated with GOA and tested the hypothesis in a population-based cohort. METHODS: Study participants were derived from the Chingford study. Kellgren-Lawrence (KL grades and the individual features of osteophytes and joint space narrowing (JSN were scored from radiographs of hands, knees, hips, and lumbar spines. The total KL score, osteophyte score, and JSN score were calculated and used as indicators of the total burden of radiographic OA. Forty-one common SNPs within SMAD3 were genotyped using the Illumina HumanHap610Q array. Linear regression modelling was used to test the association between the total KL score, osteophyte score, and JSN score and each of the 41 SNPs, with adjustment for patient age and BMI. Permutation testing was used to control the false positive rate. RESULTS: A total of 609 individuals were included in the analysis. All were Caucasian females with a mean age of 60.9±5.8. We found that rs3825977, with a minor allele (T frequency of 20%, in the last intron of SMAD3, was significantly associated with total KL score (β = 0.14, Ppermutation = 0.002. This association was stronger for the total JSN score (β = 0.19, Ppermutation = 0.002 than for total osteophyte score (β = 0.11, Ppermutation = 0.02. The T allele is associated with a 1.47-fold increased odds for people with 5 or more joints to be affected by radiographic OA (Ppermutation = 0.046. CONCLUSION: We found that SMAD3 is significantly associated with the total burden of radiographic OA. Further studies are required to reveal the mechanism of the association.

  3. The effects of intraarticular administration of hyaluronan in a model of early osteoarthritis in sheep. I. Gait analysis and radiological and morphological studies.

    Science.gov (United States)

    Ghosh, P; Read, R; Armstrong, S; Wilson, D; Marshall, R; McNair, P

    1993-06-01

    Using a model of early osteoarthritis (OA) induced in ovine joints by medial meniscectomy, the intraarticular effects of two hyaluronic acid (HA) preparations (AHA and DHA) were investigated. DHA was an HA preparation with an average molecular weight (MW) of approximately 2.0 x 10(6) d, and AHA had a MW of approximately 8 x 10(5) d. Animals (n = 5) were injected intraarticularly with 1 mL (10 mg/mL) of either HA preparation once a week for 5 weeks beginning 16 weeks after initiation of arthropathy. Meniscectomized, saline (1.0 mL)-injected animals (n = 5) and nonoperated sheep (n = 5) were used for controls. Force-plate analysis of gait and radiographic changes in joints were evaluated in these groups before and after intraarticular treatment. At necropsy, cartilage gross morphology, osteophyte development, and cartilage histopathology were examined. Meniscectomized joints were characterized by erosions and fissuring of cartilage of the medial compartment with areas of decreased matrix staining for proteoglycans. Osteophytes were present at the medial joint margins. Saline-treated meniscectomized animals showed reduced loading of the operated limb using the force plate. Force-plate analysis of walking animals before and after treatment with either AHA or DHA indicated some normalization of joint loading. However, osteophyte scores for meniscectomized joints injected with AHA and DHA were higher after treatment than those of the corresponding saline-treated group. Although the gross cartilage damage was lower than in saline-treated controls for both the HA-treated groups, the histological scores did not support this conclusion. Indeed, the tibial score for the DHA group was higher than for the AHA group (P sheep stifle (knee) joints resulted in matrix changes similar to those described for early OA in humans. Both HA preparations appeared to improve gait, suggesting decreased lameness. Increased joint loading associated with gait improvement may account for the

  4. Footballer's ankle: a case report

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Footballer' s ankle is anterior bony spur or anterior impingement symptom of the ankle with anterior ankle pain, limited and painful dorsiflexion. The cause is commonly seen in athletes and dancers, and is probably due to repetitive minor trauma. The condition was firstly described by Morris;1 McMurray2 reported good results from excision of the spurs, naming it footballer's ankle. Opening resection of osteophytes of the anterior tibial and superior talar is an effective treatment for anterior impingement of the ankle.

  5. Rapid directional change degrades GPS distance measurement validity during intermittent intensity running.

    Directory of Open Access Journals (Sweden)

    Jonathan C Rawstorn

    Full Text Available Use of the Global Positioning System (GPS for quantifying athletic performance is common in many team sports. The effect of running velocity on measurement validity is well established, but the influence of rapid directional change is not well understood in team sport applications. This effect was systematically evaluated using multidirectional and curvilinear adaptations of a validated soccer simulation protocol that maintained identical velocity profiles. Team sport athletes completed 90 min trials of the Loughborough Intermittent Shuttle-running Test movement pattern on curvilinear, and multidirectional shuttle running tracks while wearing a 5 Hz (with interpolated 15 Hz output GPS device. Reference total distance (13 200 m was systematically over- and underestimated during curvilinear (2.61±0.80% and shuttle (-3.17±2.46% trials, respectively. Within-epoch measurement uncertainty dispersion was widest during the shuttle trial, particularly during the jog and run phases. Relative measurement reliability was excellent during both trials (Curvilinear r = 1.00, slope = 1.03, ICC = 1.00; Shuttle r = 0.99, slope = 0.97, ICC = 0.99. Absolute measurement reliability was superior during the curvilinear trial (Curvilinear SEM = 0 m, CV = 2.16%, LOA ± 223 m; Shuttle SEM = 119 m, CV = 2.44%, LOA ± 453 m. Rapid directional change degrades the accuracy and absolute reliability of GPS distance measurement, and caution is recommended when using GPS to quantify rapid multidirectional movement patterns.

  6. 曲線テーパ導波路を用いた偏波分離変換器

    OpenAIRE

    藤村, 峻也

    2016-01-01

    A curvilinearly tapered waveguide is introduced to improve the characteristics of a polarization splitter and converter, whose characteristics are investigated by the beam-propagation method. To achieve a splitter and converter with a short device length, a conventional linearly tapered core is transformed into a curvilinearly tapered one. The transformed structure achieves both crosstalk and extinction ratio of less than -15dB over a wide wavelength range of 1.33 µm to 1.7µm with a quarter d...

  7. Triangular Differential Quadrature for Bending Analysis of Reissner Plates with Curved Boundaries

    Institute of Scientific and Technical Information of China (English)

    华永霞; 钟宏志

    2003-01-01

    The recently proposed concept of the triangular differential quadrature method (TDQM) is applied to the bending analysis of Reissner plates with various curvilinear geometries subjected to various combinations of boundary conditions. A unit isosceles right triangle is used as the standard triangle for all the derivatives expressed using the triangular differential quadrature rule. Geometric transformations are introduced using basis functions to determine the weighting coefficients for the triangular differential quadrature to map an arbitrary curvilinear triangle into the standard triangle. The triangular differential quadrature method provides good accuracy and rapid convergence relative to other available exact and numerical results.

  8. FINITE PROXIMATE METHOD FOR CONVECTION-DIFFUSION EQUATION

    Institute of Scientific and Technical Information of China (English)

    ZHAO Ming-deng; LI Tai-ru; HUAI Wen-xin; LI Liang-liang

    2008-01-01

    A finite proximate method was presented to solve the convection-diffusion equation in curvilinear grids. The method has characteristics of automatic upwind effect and the good stability. It was verified through exact solution and other calculation results of two-dimensional dam-break flow in a frictionless, horizontal channel. The calculation results are in good agreement with the exact solution and other calculation results, which show that the finite proximate method can be applied to solve the convection-diffusion equation directly not only in the rectangular grids, but also in the curvilinear grids.

  9. Quaternion wave equations in curved space-time

    Science.gov (United States)

    Edmonds, J. D., Jr.

    1974-01-01

    The quaternion formulation of relativistic quantum theory is extended to include curvilinear coordinates and curved space-time in order to provide a framework for a unified quantum/gravity theory. Six basic quaternion fields are identified in curved space-time, the four-vector basis quaternions are identified, and the necessary covariant derivatives are obtained. Invariant field equations are derived, and a general invertable coordinate transformation is developed. The results yield a way of writing quaternion wave equations in curvilinear coordinates and curved space-time as well as a natural framework for solving the problem of second quantization for gravity.

  10. Keystone ø-lap til rekonstruktion af huddefekter

    DEFF Research Database (Denmark)

    Breiting, Line Bro; Venzo, Alessandro; Dahlstrøm, Karin

    2009-01-01

    INTRODUCTION: The keystone design perforator island flap was first described in 2003. It is a local flap based on axial perforators from the underlying structures. It is designed as a curvilinear shaped trapezoidal design flap which is essentially two V-Y flaps end to end. Most reports are of the......INTRODUCTION: The keystone design perforator island flap was first described in 2003. It is a local flap based on axial perforators from the underlying structures. It is designed as a curvilinear shaped trapezoidal design flap which is essentially two V-Y flaps end to end. Most reports...

  11. The vibrational progressions of the N-->V electronic transition of ethylene: a test case for the computation of Franck-Condon factors of highly flexible photoexcited molecules.

    Science.gov (United States)

    Borrelli, Raffaele; Peluso, Andrea

    2006-11-21

    The vibrational progressions of the N-->V electronic transition of ethylene--a test case for the computation of Franck-Condon factors between electronic states exhibiting very different equilibrium geometries--have been calculated by using both the Cartesian and the curvilinear internal coordinate representations of the normal modes of vibration. The comparison of the theoretical spectra with the experimental one shows that the Cartesian representation yields vibrational progressions which are not observed in the experimental spectrum, whereas the curvilinear one gives a very satisfying agreement, even in harmonic approximation.

  12. Thermal Testing of Tow-Placed, Variable Stiffness Panels

    Science.gov (United States)

    Wu, K. Chauncey; Guerdal, Zafer

    2001-01-01

    Commercial systems for precise placement of pre-preg composite tows are enabling technology that allows fabrication of advanced composite structures in which the tows may be precisely laid down along curvilinear paths within a given ply. For laminates with curvilinear tow paths, the fiber orientation angle varies continuously throughout the laminate, and is not required to be straight and parallel in each ply as in conventional composite laminates. Hence, the stiffness properties vary as a function of location in the laminate, and the associated composite structure is called a "variable stiffness" composite structure.

  13. Rethinking the effects of stressors: a longitudinal study on personal initiative.

    Science.gov (United States)

    Fay, Doris; Sonnentag, Sabine

    2002-07-01

    This study examined the relationship between stressors at work and personal initiative (PI), one proactive concept of extra-role performance. Using a control theory framework to describe the stress process, the authors hypothesized that stressors should be positively related to PI. This departs from findings of negative relationships between stressors and other types of performance. Furthermore, curvilinear relationships were tested. The analyses, based on 4 measurement waves of a longitudinal field study with 172 to 193 participants, showed that stressors were positively related to subsequent changes in PI; there was no support for a curvilinear relationship. PMID:12148954

  14. The Relationship between Osseous Changes of the Temporomandibular Joint and RDC/TMD Groups in CBCT Images

    Directory of Open Access Journals (Sweden)

    Mahrokh Imanimoghaddam

    2014-09-01

    Full Text Available Abstract Introduction: Temporomandibular joint disorders (TMD are the most common disorders of the jaw, and despite their clinical importance, they are not completely understood. This study was aimed to evaluate the changes of temporomandibular joint (TMJ on cone beam computed tomography (CBCT images in disc displacement vs. osteoarthritis of the TMJ. Methods: In this study, 45 patients, including 37 women and 8 men (13-89 years of age, were examined. The patients were selected based on RDC/TMD criteria and group I disorders were excluded from the study. Accordingly, group II consisted of 43 joints with jaw clicking or displaced discs, and group III comprised 46 joints with crepitus. CBCT images in sagittal, coronal, and axial sections were examined to assess osseous changes in terms of flattening, sclerosis, erosion, resorption, and osteophyte formation. Data were analyzed using statistical tests including the chi-square, Mann-Whitney, and Kolmogorov-Smirnov tests with the confidence interval of 95%. Results: Mann-Whitney test for the comparison of mean age between groups II and III was not statistically significant (p value=0.06. A significant differences was found between two (RDC/TMD groups according to the prevalence of condylar erosion, resorption, and osteophyte (p

  15. The Influence of Magnetic Resonance Imaging Findings of Degenerative Disease on Dual-Energy X-ray Absorptiometry Measurements in Middle-Aged Men

    Energy Technology Data Exchange (ETDEWEB)

    Donescu, O.S.; Battie, M.C.; Videman, T. [Faculty of Rehabilitation Medicine and Dept. of Physical Therapy, Univ. of Alberta (Canada)

    2007-02-15

    Purpose: To examine degenerative features based on magnetic resonance imaging (MRI) measurements at the lumbar spine in relation to dual-energy X-ray absorptiometry (DXA), and to investigate whether bone mineral density (BMD) is reflected in the substitution of bone trabecular structure by fat at the vertebral body level indicated by MRI T1 relaxation time, endplate concavity, and hypertrophic (osteophytes and endplate sclerosis) MRI findings. Material and Methods: The sample for this cross-sectional study was composed of 102 subjects, 35-70 years old, from a population-based cohort. Data collection included DXA in the anterior-posterior projection at the L1-L4 vertebrae and right femoral neck, and MRI of the lumbar spine in the midsagittal plane. Results: Age, vertebral signal intensity, osteophytes, and endplate concavity collectively explained 20% of the variance in spine BMD. Conclusion: The study findings suggest that degenerative findings based on MRI measurements at the lumbar spine have an influence on bone assessment using DXA. Therefore, an overall bone assessment such as DXA might not offer an accurate measure of BMD.

  16. Progressive dysphagia and neck pain due to diffuse idiopathic skeletal hyperostosis of the cervical spine: a case report and literature review

    Directory of Open Access Journals (Sweden)

    Zhang C

    2014-03-01

    Full Text Available Chao Zhang, Dike Ruan, Qing He, Tianyong Wen, Pushan YangDepartment of Orthopedic Surgery, Navy General Hospital, Beijing, People's Republic of ChinaAbstract: Diffuse idiopathic skeletal hyperostosis (DISH is considered an underdiagnosed and mostly asymptomatic nonprimary osteoarthritis. The etiology of DISH remains unknown and the validated diagnostic criteria are absent. This condition is still recognized radiologically only. Rarely, large projecting anterior osteophytes result in esophageal impingement and distortion leading to dysphagia. We report the case of progressive dysphagia and neck pain due to DISH of the cervical spine in a 70-year-old man, which was surgically removed with excellent postoperative results and complete resolution of symptoms. Imaging studies, surgical findings, and histopathological examinations were used to support the diagnosis. The patient was successfully treated with total excision of the anterior osteophytes with no evidence of recurrence 12 months after surgery. In this report, we also discuss the clinical features and perioperative considerations in combination with a literature review. Our patient illustrates that clinicians should be aware of this rare clinical manifestation as the presenting feature of DISH in cervical spine. Surgical decompression through osteophytectomy is effective for patients who fail conservative treatment.Keywords: diffuse idiopathic skeletal hyperostosis, cervical spine, dysphagia

  17. The Influence of Magnetic Resonance Imaging Findings of Degenerative Disease on Dual-Energy X-ray Absorptiometry Measurements in Middle-Aged Men

    International Nuclear Information System (INIS)

    Purpose: To examine degenerative features based on magnetic resonance imaging (MRI) measurements at the lumbar spine in relation to dual-energy X-ray absorptiometry (DXA), and to investigate whether bone mineral density (BMD) is reflected in the substitution of bone trabecular structure by fat at the vertebral body level indicated by MRI T1 relaxation time, endplate concavity, and hypertrophic (osteophytes and endplate sclerosis) MRI findings. Material and Methods: The sample for this cross-sectional study was composed of 102 subjects, 35-70 years old, from a population-based cohort. Data collection included DXA in the anterior-posterior projection at the L1-L4 vertebrae and right femoral neck, and MRI of the lumbar spine in the midsagittal plane. Results: Age, vertebral signal intensity, osteophytes, and endplate concavity collectively explained 20% of the variance in spine BMD. Conclusion: The study findings suggest that degenerative findings based on MRI measurements at the lumbar spine have an influence on bone assessment using DXA. Therefore, an overall bone assessment such as DXA might not offer an accurate measure of BMD

  18. Micro-CT Arthrographic Analysis of Monosodium Iodoacetate- Induced Osteoarthritis in Rat Knees

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jong Won [Samsung Medical Center, Sungkyunkwan University, Seoul (Korea, Republic of); Kang, Heung Sik [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Hong, Sung Hwan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2010-10-15

    To evaluate the arthrographic findings of MIA-induced osteoarthritis in rat knees using the micro-CT arthrography. Intra-articular monosodium iodoacetate (MIA) injection-induced arthritis was induced in the right knees of twelve rats; their left knees served as the control group. Eight weeks after MIA injection, micro-CT arthrography was performed on each knee. We measured the thickness of retro-patellar cartilages, the distances of tibio-femoral joint space, subchondral bone plate thickness, tibial epiphyseal height, and transverse patellar diameter. Subchondral trabecular bone indices were measured in the tibial lateral condylar epiphysis. The data were analyzed statistically using a paired t-test. The retro-patellar articular cartilage showed thinning on the right side that had been induced to develop osteoarthritis. The right knees showed a significant reduction in the distance of the tibio-femoral joint space, prominent patellar osteophytes, and the resorption of subchondral bone. Among the subchondral trabecular bone indices, percent bone volume, and trabecular thickness was reduced on the right side. The articular cartilage thickness of MIA-induced arthritis model could be measured using micro- CT arthrography. It was possible to evaluate the osteoarthritic findings including the change in subchondral bone plate thickness, osteophyte formation, and subchondral bone resorption, as well as quantitatively analyze the trabecular bone indices.

  19. Pathological phalanges in a camarasaurid sauropod dinosaur and implications on behaviour

    Directory of Open Access Journals (Sweden)

    Emanuel Tschopp

    2016-02-01

    Full Text Available Several types of pathological bony overgrowth are known from various dinosaur taxa but, except for stress fractures, are rarely reported from appendicular elements. Herein we describe pathological manual and pedal phalanges of a camarasaurid sauropod (SMA 0002, which show features rarely recognised in non-avian dinosaurs. They include lateral osteophytes and smoothing of phalangeal articular surfaces, a deep pit, proximal enthesophytes in pedal unguals, distal overgrowth associated with a fracture, and a knob-like overgrowth lateral to the distal condyles of a pedal phalanx. Their causes were assessed by means of visual examination, CT scans, and bone histology, where possible. The lateral osteophytes are interpreted as symptoms of osteoarthritis. The ossified tendon insertions in the unguals are most probably the result of prolonged, heavy use of the pedal claws, possibly for scratchdigging. The distal overgrowth is interpreted to have developed due to changed stress regimes, and to be the cause for the fracture. The deep pit represents most likely a case of osteochondrosis, whereas the knob-like overgrowth likely represents a post-traumatic phenomenon not previously reported in dinosaurs. The study confirms that a rigorous assessment of pathologies can yield information about behaviour in long-extinct animals.

  20. A novel algorithm for a precise analysis of subchondral bone alterations

    Science.gov (United States)

    Gao, Liang; Orth, Patrick; Goebel, Lars K. H.; Cucchiarini, Magali; Madry, Henning

    2016-09-01

    Subchondral bone alterations are emerging as considerable clinical problems associated with articular cartilage repair. Their analysis exposes a pattern of variable changes, including intra-lesional osteophytes, residual microfracture holes, peri-hole bone resorption, and subchondral bone cysts. A precise distinction between them is becoming increasingly important. Here, we present a tailored algorithm based on continuous data to analyse subchondral bone changes using micro-CT images, allowing for a clear definition of each entity. We evaluated this algorithm using data sets originating from two large animal models of osteochondral repair. Intra-lesional osteophytes were detected in 3 of 10 defects in the minipig and in 4 of 5 defects in the sheep model. Peri-hole bone resorption was found in 22 of 30 microfracture holes in the minipig and in 17 of 30 microfracture holes in the sheep model. Subchondral bone cysts appeared in 1 microfracture hole in the minipig and in 5 microfracture holes in the sheep model (n = 30 holes each). Calculation of inter-rater agreement (90% agreement) and Cohen’s kappa (kappa = 0.874) revealed that the novel algorithm is highly reliable, reproducible, and valid. Comparison analysis with the best existing semi-quantitative evaluation method was also performed, supporting the enhanced precision of this algorithm.

  1. Arthroscopic tibiotalar and subtalar joint arthrodesis.

    Science.gov (United States)

    Roussignol, X

    2016-02-01

    Arthroscopy has become indispensable for performing tibiotalar and subtalar arthrodesis. Now in 2015, it is the gold-standard surgical technique, and open surgery is reserved only for cases in which arthroscopy is contraindicated: material ablation after consolidation failure, osteophytes precluding a work chamber, excentric talus, severe malunion, bone defect requiring grafting, associated midfoot deformity, etc. The first reports of arthroscopic tibiotalar and subtalar arthrodesis date from the early 1990s. Consolidation rates were comparable to open surgery, but with significantly fewer postoperative complications: infection, skin necrosis, etc. Arthroscopy was for many years reserved to moderate deformity, with frontal or sagittal deviation less than 10°. The recent literature, however, seems to extend indications, the only restriction being the surgeon's experience. Tibiotalar arthrodesis on a posterior arthroscopic approach remains little used. And yet the posterior work chamber is much larger, and initial series showed consolidation rates similar to those of an anterior approach. The surgical technique for posterior tibiotalar arthrodesis was described by Van Dijk et al., initially using a posterior para-Achilles approach. This may be hampered by posterior osteophytes or ankylosis of the subtalar joint line (revision of non-consolidated arthrodesis, sequelae of calcaneal thalamus fracture) and is now used only by foot and ankle specialists. Posterior double tibiotalar-subtalar arthrodesis, described by Devos Bevernage et al., is facilitated by transplantar calcaneo-talo-tibial intramedullary nailing. PMID:26797006

  2. Relationships between rotator cuff tear types and radiographic abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Hyun; Chun, Kyung Ah; Lee Soo Jung; Kang, Min Ho; Yi, Kyung Sik; Zhang, Ying [Dept. of Diagnostic Radiology, College of Medicine, Chungbuk National University, Cheongju (Korea, Republic of)

    2014-11-15

    To determine relationships between different types of rotator cuff tears and radiographic abnormalities. The shoulder radiographs of 104 patients with an arthroscopically proven rotator cuff tear were compared with similar radiographs of 54 age-matched controls with intact cuffs. Two radiologists independently interpreted all radiographs for; cortical thickening with subcortical sclerosis, subcortical cysts, osteophytes in the humeral greater tuberosity, humeral migration, degenerations of the acromioclavicular and glenohumeral joints, and subacromial spurs. Statistical analysis was performed to determine relationships between each type of rotator cuff tears and radiographic abnormalities. Inter-observer agreements with respect to radiographic findings were analyzed. Humeral migration and degenerative change of the greater tuberosity, including sclerosis, subcortical cysts, and osteophytes, were more associated with full-thickness tears (p < 0.01). Subacromial spurs were more common for full-thickness and bursal-sided tears (p < 0.01). No association was found between degeneration of the acromioclavicular or glenohumeral joint and the presence of a cuff tear. Different types of rotator cuff tears are associated with different radiographic abnormalities.

  3. Risk Factors for the Development of Adjacent Segment Disease Following Anterior Cervical Arthrodesis

    Directory of Open Access Journals (Sweden)

    Ezgi Akar

    2015-06-01

    Full Text Available Aim: The aim of this study was to clinically and radiologically evaluate the efficacy of anterior cervical discectomy and fusion (ACDF in the treatment of adjacent level degeneration. Methods: We retrospectively evaluated 89 patients (55 females, 34 males who underwent ACDF. Adjacent segment degeneration findings were evaluated by investigating new osteophyte formation, growth of existing osteophytes, ossification of the anterior longitudinal ligament, presence of intervertebral disc space narrowing, sagittal alignment and range of motion (ROM using serial radiographs and magnetic resonance imaging. Results: The mean age of the 89 patients was 41.3 (24-76 years. The mean follow-up duration was 34.3 (12-64 months. Radiographic evidence of adjacent segment degeneration was observed in 12 patients (13.4%. Nine (75% patients had new complaints. Of the patients who had degenerative changes, 7 were (58% were male, 5 (42% were female; the mean age was 46 (30- 62 years. It was observed that the level of fusion and the number of fusion did not increase the adjacent segment degeneration. All of 12 patients were observed to have a non lordotic cervical spine and increased ROM. Conclusion: Development of degeneration at the level adjacent to region anterior cervical discectomy and fusion performed is higher compared to non-adjacent levels. The level of fusion and the number of fusion levels have no effect on the development of degeneration. (The Medical Bulletin of Haseki 2015; 53:120-3

  4. Temporomandibular joint osteoarthritis: cone beam computed tomography findings, clinical features, and correlations.

    Science.gov (United States)

    Cömert Kiliç, S; Kiliç, N; Sümbüllü, M A

    2015-10-01

    The aim of this study was to determine the prevalence of and associations between clinical signs and symptoms and cone beam computed tomography (CBCT) findings of temporomandibular joint osteoarthritis (TMJ-OA). Seventy-six patients (total 117 TMJ) with osteoarthritis were included in this study. Clinical signs and symptoms and CBCT findings were reviewed retrospectively. A considerable decrease in mandibular motions and mastication efficiency, and considerable increase in joint sounds and general pain complaints were observed. The most frequent condylar bony changes were erosion (110 joints, 94.0%), followed by flattening (108 joints, 92.3%), osteophytes (93 joints, 79.5%), hypoplasia (22 joints, 18.8%), sclerosis (14 joints, 12.0%), and subchondral cyst (four joints, 3.4%). Flattening of the articular eminence and pneumatization were each observed in five joints. Forty-one patients had bilateral degeneration and 35 had unilateral degeneration. Hypermobility was detected in 47 degenerative joints. Masticatory efficiency was negatively correlated with both condylar flattening and sclerosis, and general pain complaints was positively correlated with condylar flattening. Condylar erosion, flattening, osteophytes, pain, joint sounds, reduced jaw movements, and worsened mastication were common findings in TMJ-OA in the present study. Poor correlations were found between osseous changes and clinical signs and symptoms of TMJ-OA. CBCT is a powerful diagnostic tool for the diagnosis of TMJ-OA. PMID:26194774

  5. Osteoarthritis of the thumb carpometacarpal joint: Correlation of ultrasound appearances to disability and treatment response

    International Nuclear Information System (INIS)

    Aim: To evaluate grading of thumb carpometacarpal joint (CMCJ) osteoarthritis (OA) using ultrasound, correlating findings with disability and treatment response. Materials and methods: Patients with symptomatic thumb OA attending for ultrasound-guided CMCJ steroid injection and a group of asymptomatic controls were recruited prospectively. Thumb CMCJ ultrasound was graded (osteophytes, joint-space narrowing, capsule size, and measured capsule size), and a Disabilities of the Arm Shoulder and Hand (DASH) questionnaire was completed for each patient. Symptomatic patients then underwent injection with DASH repeated 6 weeks post-treatment. Ultrasound features were correlated with the initial DASH disability score and response as defined by change in DASH 6 weeks after treatment. Results: Thirty-one patients with symptomatic OA and 37 asymptomatic controls were recruited. With the exception of osteophytes (p = 0.017), no statistically significant correlation was demonstrated between severity of ultrasound features and patient disability. However, all features demonstrated statistically significant higher grades in the symptomatic group compared to controls. Ultrasound grading did not have statistical correlation with treatment response. Conclusion: No correlation was found between the majority of ultrasound features and the clinical severity of OA or likely response to treatment. However, these features are significantly more common in the symptomatic population

  6. Market Earnings and Household Work: New Tests of Gender Performance Theory

    Science.gov (United States)

    Schneider, Daniel

    2011-01-01

    I examine the contested finding that men and women engage in gender performance through housework. Prior scholarship has found a curvilinear association between earnings share and housework that has been interpreted as evidence of gender performance. I reexamine these findings by conducting the first such analysis to use high-quality time diary…

  7. Developmental Changes in Parent-Child Communication throughout Adolescence

    Science.gov (United States)

    Keijsers, Loes; Poulin, François

    2013-01-01

    This study examined how parent-child communication regarding adolescent unsupervised activities develops over the course of adolescence. We used questionnaire data from 390 adolescents (58% girls; 90% European Canadian) who were followed from age 12 to 19. Latent growth curve modeling revealed curvilinear developmental changes that differed for…

  8. Emotionally Numb: Desensitization to Community Violence Exposure among Urban Youth

    Science.gov (United States)

    Kennedy, Traci M.; Ceballo, Rosario

    2016-01-01

    Community violence exposure (CVE) is associated with numerous psychosocial outcomes among youth. Although linear, cumulative effects models have typically been used to describe these relations, emerging evidence suggests the presence of curvilinear associations that may represent a pattern of emotional desensitization among youth exposed to…

  9. Introduction to the general relativity; Introduction a la relativite generale

    Energy Technology Data Exchange (ETDEWEB)

    Radix, J.C.

    1994-12-31

    This work deals with the introduction of the general relativity including the introduction of the tensorial calculation, the Euclidean space in curvilinear coordinates, the Riemann space, the recalls and complements of the restricted relativity and the elements of the general relativity. (O.L.) 83 figs., 3 tabs.

  10. Application of Adaptive Counseling and Therapy to Career Counseling.

    Science.gov (United States)

    Anderson, Mary Z.; Tracey, Terence J.

    1995-01-01

    Adaptive Counseling and Therapy theory predicts that counseling efficacy depends on a match between counselor style and client readiness. Data from 137 females and 54 males showed a negative relationship between client readiness and preference for directive counseling and a curvilinear (inverted U) relationship between readiness and preference for…

  11. My Precious

    DEFF Research Database (Denmark)

    Laursen, Keld; Salter, Ammon

    2005-01-01

    that both strategies are curvilinearly (taking an invertedU-shape) related to innovative performance, indicting that some firms may sufferfrom a myopia of protectiveness, relying too heavily on appropriation to the detrimentof other activities.Keywords: Appropriability, Intellectual property rights...

  12. Height predicts jealousy differently for men and women

    NARCIS (Netherlands)

    Buunk, Abraham P.; Park, Justin H.; Zurriaga, Rosario; Klavina, Liga; Massar, Karlijn

    2008-01-01

    Because male height is associated with attractiveness, dominance, and reproductive success, taller men may be less jealous. And because female height has a curvilinear relationship with health and reproductive success (with average-height females having the advantages), female height may have a curv

  13. FIRO-B, Machiavellianism, and teams.

    Science.gov (United States)

    Macrosson, W D; Semple, J H

    2001-06-01

    A correlational study using the Mach IV and FIRO-B questionnaires examined the attitudes of 120 postgraduate and undergraduate students, the majority of whom had significant work experience. A curvilinear relationship observed between the FIRO-B and Mach IV scales calls into question an aspect of Will Schutz's prescription for interpersonal compatibility.

  14. Who Listens to Trash Talk?: Education and Public Media Effects on Recycling Behavior.

    Science.gov (United States)

    Martinez, Michael D.; Scicchitano, Michael J.

    1998-01-01

    Observes that research has shown a curvilinear relationship between education and media effects, with media having the greatest effect on people with moderate levels of education. Examines the effects of public service messages about recycling, and finds that the messages actually have greater impact on people with higher levels of education. (DSK)

  15. An Overview of Plasma Confinement in Toroidal Systems

    OpenAIRE

    Dini, Fatemeh; Baghdadi, Reza; Amrollahi, Reza; Khorasani, Sina

    2009-01-01

    This overview presents a tutorial introduction to the theory of magnetic plasma confinement in toroidal confinement systems with particular emphasis on axisymmetric equilibrium geometries, and tokamaks. The discussion covers three important aspects of plasma physics: Equilibrium, Stability, and Transport. The section on equilibrium will go through an introduction to ideal magnetohydrodynamics, curvilinear system of coordinates, flux coordinates, extensions to axisymmetric equilibrium, Grad-Sh...

  16. Correction of dispersion distortion of femtosecond pulses by using the non-planar surface of diffractive optical elements

    Institute of Scientific and Technical Information of China (English)

    I.V.Minin; O.V.Minin

    2004-01-01

    Peculiarities of propagation of femtosecond pulses through a focusing diffractive optical element(DOE)are considered.It is shown that the time delay between the pulse and phase wavefronts can be decreased by fabricating the DOE on the optimal curvilinear surface.

  17. Advancing Age, Advantaged Youth: Parental Age and the Transmission of Resources to Children

    Science.gov (United States)

    Powell, Brian; Steelman, Lala Carr; Carini, Robert M.

    2006-01-01

    Using data from the National Education Longitudinal Study of 1988, we identify parental age as influential in the parental provision of economic resources, social capital and cultural capital to adolescents, as well as in parental educational expectations for their children. At the bivariate level, the relationship is curvilinear, suggesting that…

  18. DEVELOPMENT AND APPLICATIONS OF WENO SCHEMES IN CONTINUUM PHYSICS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper briefly presents the general ideas of high order accurate weighted essentially non-oscillatory (WENO) schemes, and describes the similarities and differences of the two classes of WENO schemes: finite volume schemes and finite difference schemes. We also briefly mention a recent development of WENO schemes,namely an adaptive approach within the finite difference framework using smooth time dependent curvilinear coordinates.``

  19. Travel Blankets

    Science.gov (United States)

    Coy, Mary

    2009-01-01

    Spry Middle School's annual eighth-grade trip to Washington, District of Columbia, coincided with the opening of the National Museum of the American Indian. The museum, with its distinctive curvilinear architecture covered in Kasota limestone, stands as a wonderful testament to the rich culture and history of the many and diverse Native American…

  20. Logic and Belief across the Lifespan: The Rise and Fall of Belief Inhibition during Syllogistic Reasoning

    Science.gov (United States)

    De Neys, Wim; Van Gelder, Elke

    2009-01-01

    Popular reasoning theories postulate that the ability to inhibit inappropriate beliefs lies at the heart of the human reasoning engine. Given that people's inhibitory capacities are known to rise and fall across the lifespan, we predicted that people's deductive reasoning performance would show similar curvilinear age trends. A group of children…

  1. Cross-Domain Effects of Music and Language Experience on the Representation of Pitch in the Human Auditory Brainstem

    Science.gov (United States)

    Bidelman, Gavin M.; Gandour, Jackson T.; Krishnan, Ananthanarayan

    2011-01-01

    Neural encoding of pitch in the auditory brainstem is known to be shaped by long-term experience with language or music, implying that early sensory processing is subject to experience-dependent neural plasticity. In language, pitch patterns consist of sequences of continuous, curvilinear contours; in music, pitch patterns consist of relatively…

  2. Hybrid immersed boundary method for airfoils with a trailing-edge flap

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Behrens, Tim; Shen, Wen Zhong;

    2013-01-01

    -edge flap is simulated using the immersed boundary method on a curvilinear mesh. An existing in-house-developed flow solver is employed to solve the incompressible Reynolds-Averaged Navier-Stokes equations together with the k-ω turbulence model. To achieve consistent wall boundary conditions at the immersed...

  3. National Income, Inequality and Global Patterns of Cigarette Use

    Science.gov (United States)

    Pampel, Fred

    2007-01-01

    Declining tobacco use in high-income nations and rising tobacco use in low- and middle-income nations raises questions about the sources of worldwide patterns of smoking. Theories posit a curvilinear influence of national income based on the balance of affordability and health-cost effects. In addition, however, economic inequality, gender…

  4. Layout analysis of handwritten historical documents for searching the archive of the cabinet of the Dutch Queen

    NARCIS (Netherlands)

    Bulacu, Marius; van Koert, Rutger; Schomaker, L.R.B.; van der Zant, Tijn; Werner, B

    2007-01-01

    In this paper, we describe the structure and the performance of a layout analysis system developed for processing the handwritten documents contained in a large historical collection of very high importance in the Netherlands. We introduce a method based on contour tracing that generates curvilinear

  5. Impact of contour on aesthetic judgments and approach-avoidance decisions in architecture.

    Science.gov (United States)

    Vartanian, Oshin; Navarrete, Gorka; Chatterjee, Anjan; Fich, Lars Brorson; Leder, Helmut; Modroño, Cristián; Nadal, Marcos; Rostrup, Nicolai; Skov, Martin

    2013-06-18

    On average, we urban dwellers spend about 90% of our time indoors, and share the intuition that the physical features of the places we live and work in influence how we feel and act. However, there is surprisingly little research on how architecture impacts behavior, much less on how it influences brain function. To begin closing this gap, we conducted a functional magnetic resonance imaging study to examine how systematic variation in contour impacts aesthetic judgments and approach-avoidance decisions, outcome measures of interest to both architects and users of spaces alike. As predicted, participants were more likely to judge spaces as beautiful if they were curvilinear than rectilinear. Neuroanatomically, when contemplating beauty, curvilinear contour activated the anterior cingulate cortex exclusively, a region strongly responsive to the reward properties and emotional salience of objects. Complementing this finding, pleasantness--the valence dimension of the affect circumplex--accounted for nearly 60% of the variance in beauty ratings. Furthermore, activation in a distributed brain network known to underlie the aesthetic evaluation of different types of visual stimuli covaried with beauty ratings. In contrast, contour did not affect approach-avoidance decisions, although curvilinear spaces activated the visual cortex. The results suggest that the well-established effect of contour on aesthetic preference can be extended to architecture. Furthermore, the combination of our behavioral and neural evidence underscores the role of emotion in our preference for curvilinear objects in this domain.

  6. THE UNCONVENTIONAL DESIGN OF THE ELECTRODYNAMIC TRANSPORT SYSTEMS

    Directory of Open Access Journals (Sweden)

    V. A. Dzenzersjkyj

    2009-08-01

    Full Text Available The arrangements of electro-dynamic transport systems with the flat track structure are described and the fluctuations and stability of levitation motion of their vehicles are evaluated. It is shown that under rational choice of main parameters of the systems a stable levitation motion of the vehicles in straight-line and curvilinear sections of the track is provided.

  7. Economic Globalization, Industrialization and Deindustrialization in Affluent Democracies

    Science.gov (United States)

    Brady, David; Denniston, Ryan

    2006-01-01

    This study reexamines the relationship between economic globalization and manufacturing employment in affluent democracies. After reviewing past research, including the well-supported Rowthorn model, we propose a differentiation-saturation model that theorizes that globalization has a curvilinear relationship with manufacturing employment. Using…

  8. A numerical grid generation technique

    NARCIS (Netherlands)

    Gilding, B.H.

    1988-01-01

    The paper describes a technique for the generation of boundary-fitted curvilinear coordinate systems for the numerical solution of partial differential equations in two space dimensions. The technique is algebraic, has a transfinite character, and is based on the blending of shearing transformations

  9. In Search of Nonlinear Process-Product Functions in Existing Schooling Effects Data: I. A Reanalysis of the First Grade Reading and Mathematics Data From the Stallings and Kaskowitz Follow Through Study.

    Science.gov (United States)

    Rim, Eui-Do; Coller, Alan R.

    As an attempt to confirm the view that the relationships between certain classroom process variables and student achievement are curvilinear, first grade reading and mathematics data from the Stallings and Kaskowitz (1974) Project Follow Through Classroom Observation Evaluation were reanalyzed using orthogonal polynomial regression methods.…

  10. Numerical Investigation of Heat Transfer Augmentation through Geometrical Optimization of Vortex Generators

    DEFF Research Database (Denmark)

    Gorji, Mofid; Mirgolbabaei, Hessam; Barari, Amin;

    2010-01-01

    In this paper a two-dimensional numerical simulation of a steady incompressible and turbulent model has been carried out to study the effects of vortex generators in a compact heat exchanger in a curvilinear coordinate system. The mesh which is applied in this study is boundary fitted and has bee...

  11. A Threshold Model of Social Support, Adjustment, and Distress after Breast Cancer Treatment

    Science.gov (United States)

    Mallinckrodt, Brent; Armer, Jane M.; Heppner, P. Paul

    2012-01-01

    This study examined a threshold model that proposes that social support exhibits a curvilinear association with adjustment and distress, such that support in excess of a critical threshold level has decreasing incremental benefits. Women diagnosed with a first occurrence of breast cancer (N = 154) completed survey measures of perceived support…

  12. The Downsides of Extreme Conscientiousness for Psychological Well-being: The Role of Obsessive Compulsive Tendencies.

    Science.gov (United States)

    Carter, Nathan T; Guan, Li; Maples, Jessica L; Williamson, Rachel L; Miller, Joshua D

    2016-08-01

    Although conscientiousness exhibits positive relations with psychological well-being, theoretical and empirical work suggests individuals can be too conscientious, resulting in obsessive-compulsiveness, and therein less positive individual outcomes. However, the potential for curvilinearity between conscientiousness and well-being has been underexplored. We measured 912 subjects on facets of conscientiousness, obsessive-compulsive personality, and well-being variables (life satisfaction, job satisfaction, self-esteem, positive affect, negative affect, work stress). Methods of scoring included traditional sum-scoring, traditional item response theory (IRT), and a relatively new IRT approach. Structural models were estimated to evaluate curvilinearity. Results confirmed the curvilinear relationship between conscientiousness and well-being, and demonstrated that differential facet-level relationships underlie weaker curvilinearity at the general trait level. Consistency was found in the strength of relation between conscientiousness facets with their obsessive-compulsive variants and their contribution to decreased well-being. The most common association was that higher standing on conscientiousness facets was positively related to negative affect. Findings support the idea that extreme standing on facets of conscientiousness more strongly linked to their obsessive-compulsive variants contributed to lower well-being, highlighting the importance of considering alternative functional representations of the relationship between personality and other constructs. Future work should seek to further clarify the link between conscientiousness and negative affect. PMID:25858019

  13. The Relationship between Engagement in Cocurricular Activities and Academic Performance: Exploring Gender Differences

    Science.gov (United States)

    Zacherman, Avi; Foubert, John

    2014-01-01

    The effects of time spent in cocurricular activities on academic performance was tested. A curvilinear relationship between hours per week spent involved in cocurricular activities and grade point average was discovered such that a low amount of cocurricular involvement was beneficial to grades, while a high amount can potentially hurt academic…

  14. Numerical Analysis on Longitudinal Location Optimization of Vortex Generator in Compact Heat Exchangers

    DEFF Research Database (Denmark)

    Gorji, M.; Mirgolbababei, H.; Barari, Amin;

    2011-01-01

    In this paper, numerical, curvilinear and turbulent model has been used to investigate the effect of vortex generator's longitudinal displacement on heat transfer and fluid flow in different Reynolds numbers ranging from 500 to 3000. The numerical model has been validated with experimental result...

  15. Modeling of Airfoil Trailing Edge Flap with Immersed Boundary Method

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2011-01-01

    to simulate the moving part of the trailing edge. Over the main fixed part of the airfoil the Navier-Stokes (NS) equations are solved using a standard body-fitted finite volume technique whereas the moving trailing edge flap is simulated with the immersed boundary method on a curvilinear mesh. The obtained...

  16. Accumulation of smooth endoplasmic reticulum in Alzheimer's disease: new morphological evidence of axoplasmic flow disturbances.

    OpenAIRE

    Richard, S; Brion, Jean Pierre; Couck, A. M.; Flament Durand, Jacqueline

    1989-01-01

    Numerous enlarged neurites and presynaptic terminals containing tubulovesicular profiles of smooth endoplasmic reticulum (SER) were observed in frontal biopsies from six patients with Alzheimer's disease. These accumulations of SER probably reflect disturbances of axoplasmic flows. In addition, curvilinear tubular inclusions similar to those characteristic of Farber's disease were found in one patient. Finally, accumulation of glycogen within neurites and enlarged mitochondria were observed i...

  17. Modelling positional uncertainty of line features by accounting for stochastic deviations from straight line segments

    NARCIS (Netherlands)

    Bruin, de S.

    2008-01-01

    The assessment of positional uncertainty in line and area features is often based on uncertainty in the coordinates of their elementary vertices which are assumed to be connected by straight lines. Such an approach disregards uncertainty caused by sampling and approximation of a curvilinear feature

  18. The differential equations defining deflection of particles of ion beam from axial trajectory in electric and magnetic fields

    International Nuclear Information System (INIS)

    The exact differential equations defining deviations of the paths of charged particles from the axial trajectory are derived in curvilinear coordinates. These equations are in a form suited for carrying out relativistically correct numerical calculations of the dynamics of charged particle beams.

  19. Money Buys Financial Security and Psychological Need Satisfaction: Testing Need Theory in Affluence

    Science.gov (United States)

    Howell, Ryan T.; Kurai, Mark; Tam, Leona

    2013-01-01

    The most prominent theory to explain the curvilinear relationship between income and subjective well-being (SWB) is need theory, which proposes that increased income and wealth can lead to increased well-being in poverty because money is used to satisfy basic physiological needs. The present study tests the tenets of need theory by proposing that…

  20. Advanced Cardiovascular Monitoring

    NARCIS (Netherlands)

    de Waal, E.E.C.

    2009-01-01

    The Frank-Starling curve (the curvilinear relation between cardiac output (CO) and preload) can be used for optimalization of the blood circulation and tissue oxygenation, in order to decrease morbidity and mortality in high risk surgery and critically ill patients. Measurement of CO and preload wit

  1. Calculations of automatic chamber flux measurements of methane and carbon dioxide using short time series of concentrations

    Science.gov (United States)

    Pirk, Norbert; Mastepanov, Mikhail; Parmentier, Frans-Jan W.; Lund, Magnus; Crill, Patrick; Christensen, Torben R.

    2016-02-01

    The closed chamber technique is widely used to measure the exchange of methane (CH4) and carbon dioxide (CO2) from terrestrial ecosystems. There is, however, large uncertainty about which model should be used to calculate the gas flux from the measured gas concentrations. Due to experimental uncertainties the simple linear regression model (first-order polynomial) is often applied, even though theoretical considerations of the technique suggest the application of other, curvilinear models. High-resolution automatic chamber systems which sample gas concentrations several hundred times per flux measurement make it possible to resolve the curvilinear behavior and study the information imposed by the natural variability of the temporal concentration changes. We used more than 50 000 such flux measurements of CH4 and CO2 from five field sites located in peat-forming wetlands ranging from 56 to 78° N to quantify the typical differences between flux estimates of different models. In addition, we aimed to assess the curvilinearity of the concentration time series and test the general applicability of curvilinear models. Despite significant episodic differences between the calculated flux estimates, the overall differences are generally found to be smaller than the local flux variability on the plot scale. The curvilinear behavior of the gas concentrations within the chamber is strongly influenced by wind-driven chamber leakage, and less so by changing gas concentration gradients in the soil during chamber closure. Such physical processes affect both gas species equally, which makes it possible to isolate biochemical processes affecting the gases differently, such as photosynthesis limitation by chamber headspace CO2 concentrations under high levels of incoming solar radiation. We assess the possibility to exploit this effect for a partitioning of the net CO2 flux into photosynthesis and ecosystem respiration as an example of how high-resolution automatic chamber

  2. Topographic deformation patterns of knee cartilage after exercises with high knee flexion: an in vivo 3D MRI study using voxel-based analysis at 3T

    International Nuclear Information System (INIS)

    To implement a novel voxel-based technique to identify statistically significant local cartilage deformation and analyze in-vivo topographic knee cartilage deformation patterns using a voxel-based thickness map approach for high-flexion postures. Sagittal 3T 3D-T1w-FLASH-WE-sequences of 10 healthy knees were acquired before and immediately after loading (kneeling/squatting/heel sitting/knee bends). After cartilage segmentation, 3D-reconstruction and 3D-registration, colour-coded deformation maps were generated by voxel-based subtraction of loaded from unloaded datasets to visualize cartilage thickness changes in all knee compartments. Compression areas were found bifocal at the peripheral medial/caudolateral patella, both posterior femoral condyles and both anterior/central tibiae. Local cartilage thickening were found adjacent to the compression areas. Significant local strain ranged from +13 to -15 %. Changes were most pronounced after squatting, least after knee bends. Shape and location of deformation areas varied slightly with the loading paradigm, but followed a similar pattern consistent between different individuals. Voxel-based deformation maps identify individual in-vivo load-specific and posture-associated strain distribution in the articular cartilage. The data facilitate understanding individual knee loading properties and contribute to improve biomechanical 3 models. They lay a base to investigate the relationship between cartilage degeneration patterns in common osteoarthritis and areas at risk of cartilage wear due to mechanical loading in work-related activities. (orig.)

  3. Connectivity and neurochemistry of the commissura anterior of the pigeon (Columba livia).

    Science.gov (United States)

    Letzner, Sara; Simon, Annika; Güntürkün, Onur

    2016-02-01

    The anterior commissure (AC) and the much smaller hippocampal commissure constitute the only interhemispheric pathways at the telencephalic level in birds. Since the degeneration study from Zeier and Karten (), no detailed description of the topographic organization of the AC has been performed. This information is not only necessary for a better understanding of interhemispheric transfer in birds, but also for a comparative analysis of the evolution of commissural systems in the vertebrate classes. We therefore examined the fiber connections of the AC by using choleratoxin subunit B (CTB) and biotinylated dextran amine (BDA). Injections into subareas of the arcopallium and posterior amygdala (PoA) demonstrated contralateral projection fields within the anterior arcopallium (AA), intermediate arcopallium (AI), PoA, lateral, caudolateral and central nidopallium, dorsal and ventral mesopallium, and medial striatum (MSt). Interestingly, only arcopallial and amygdaloid projections were reciprocally organized, and all AC projections originated within a rather small area of the arcopallium and the PoA. The commissural neurons were not GABA-positive, and thus possibly not of an inhibitory nature. In sum, our neuroanatomical study demonstrates that a small group of arcopallial and amygdaloid neurons constitute a wide range of contralateral projections to sensorimotor and limbic structures. Different from mammals, in birds the neurons that project via the AC constitute mostly heterotopically organized and unidirectional connections. In addition, the great majority of pallial areas do not participate by themselves in interhemispheric exchange in birds. Instead, commissural exchange rests on a rather small arcopallial and amygdaloid cluster of neurons. PMID:26179777

  4. Tibial stress fractures in racing Standardbreds: 13 cases (1989-1993)

    International Nuclear Information System (INIS)

    To determine clinical signs, radiographic and scintigraphic findings, and performance outcome of racing Standardbreds with tibial stress fractures. Retrospective case series. 13 racing Standardbreds with tibial stress fractures. Information concerning clinical signs, diagnostic evaluation, and recommendations was obtained by review of the medical records. Performance information before and after diagnosis of the fracture was collected from racing records, and follow-up information was obtained from the owners or trainers by use of a telephone questionnaire. Horses with tibial stress fractures were moderately lame, and diagnosis was made by nuclear scintigraphy and radiography. Fractures were more likely to occur in 2-year-old horses than in older horses. The fracture location was unique for Standardbreds; 11 of 13 developed stress fractures in the mid-diaphysis of the tibia, whereas fractures in Thoroughbreds are usually in the proximal caudal or caudolateral cortex. Fractures occurred in young horses that had raced or were in advanced race training. All horses were treated with rest alone, and 10 of 13 horses raced after injury. The horses that raced after injury were able to return to a level of performance that was equal to or better than the level raced before injury. 8 of 10 horses established a lifetime-best winning time after injury. Tibial stress fractures are a cause of lameness in young racing Standardbreds. Diagnosis is aided by nuclear scintigraphy. The prognosis for return to previous level of performance after a tibial stress fracture is good

  5. Functional morphology of venous structures associated with the male and female reproductive systems in Florida manatees (Trichechus manatus latirostris).

    Science.gov (United States)

    Rommel, S A; Pabst, D A; McLellan, W A

    2001-12-01

    The reproductive organs of Florida manatees (Trichechus manatus latirostris) are surrounded by thermogenic locomotory muscles and insulating fat. Manatees are reported to maintain core body temperatures of 35.6 degrees -36.4 degrees C, temperatures known to interfere with production and maturation of viable sperm in terrestrial mammals. We describe two novel venous plexuses associated with the manatee epididymis. Each epididymis is located in a hypogastric fossa at the caudolateral extremity of the abdominal cavity. Each hypogastric fossa is lined by an inguinal venous plexus that receives cooled blood from a superficial thoracocaudal plexus. We conclude that male manatees may prevent hyperthermic insult to their reproductive tissues by feeding cooled superficial blood to venous plexuses deep within their bodies. Female manatees also possess hypogastric fossae and venous structures similar to those found in male manatees. The ovaries, uterine tubes, and distal tips of the uterine horns are located in the hypogastric fossae. We suggest that the thermovascular structures we describe also prevent hypothermic insult to female manatee reproductive tissues. The venous structures in manatees are functionally similar to structures associated with reproductive thermoregulation in cetaceans and phocid seals. Thus, these thermovascular structures appear to be convergent morphological adaptations that occur in three clades of diving mammals with independent evolutionary histories.

  6. Topographic deformation patterns of knee cartilage after exercises with high knee flexion: an in vivo 3D MRI study using voxel-based analysis at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Horng, Annie; Stockinger, M.; Notohamiprodjo, M. [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Raya, J.G. [New York University Langone Medical Center, Center for Biomedical Imaging, New York, NY (United States); Pietschmann, M. [Ludwig-Maximilians-University Hospital Munich, Department of Orthopedic Surgery, Munich (Germany); Hoehne-Hueckstaedt, U.; Glitsch, U.; Ellegast, R. [Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), Sankt Augustin (Germany); Hering, K.G. [Miner' s Hospital, Department of Diagnostic Radiology, Dortmund (Germany); Glaser, C. [Ludwig-Maximilians-University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); RZM Zentrum, Munich (Germany)

    2015-06-01

    To implement a novel voxel-based technique to identify statistically significant local cartilage deformation and analyze in-vivo topographic knee cartilage deformation patterns using a voxel-based thickness map approach for high-flexion postures. Sagittal 3T 3D-T1w-FLASH-WE-sequences of 10 healthy knees were acquired before and immediately after loading (kneeling/squatting/heel sitting/knee bends). After cartilage segmentation, 3D-reconstruction and 3D-registration, colour-coded deformation maps were generated by voxel-based subtraction of loaded from unloaded datasets to visualize cartilage thickness changes in all knee compartments. Compression areas were found bifocal at the peripheral medial/caudolateral patella, both posterior femoral condyles and both anterior/central tibiae. Local cartilage thickening were found adjacent to the compression areas. Significant local strain ranged from +13 to -15 %. Changes were most pronounced after squatting, least after knee bends. Shape and location of deformation areas varied slightly with the loading paradigm, but followed a similar pattern consistent between different individuals. Voxel-based deformation maps identify individual in-vivo load-specific and posture-associated strain distribution in the articular cartilage. The data facilitate understanding individual knee loading properties and contribute to improve biomechanical 3 models. They lay a base to investigate the relationship between cartilage degeneration patterns in common osteoarthritis and areas at risk of cartilage wear due to mechanical loading in work-related activities. (orig.)

  7. Functional morphology of venous structures associated with the male and female reproductive systems in Florida manatees (Trichechus manatus latirostris).

    Science.gov (United States)

    Rommel, S A; Pabst, D A; McLellan, W A

    2001-12-01

    The reproductive organs of Florida manatees (Trichechus manatus latirostris) are surrounded by thermogenic locomotory muscles and insulating fat. Manatees are reported to maintain core body temperatures of 35.6 degrees -36.4 degrees C, temperatures known to interfere with production and maturation of viable sperm in terrestrial mammals. We describe two novel venous plexuses associated with the manatee epididymis. Each epididymis is located in a hypogastric fossa at the caudolateral extremity of the abdominal cavity. Each hypogastric fossa is lined by an inguinal venous plexus that receives cooled blood from a superficial thoracocaudal plexus. We conclude that male manatees may prevent hyperthermic insult to their reproductive tissues by feeding cooled superficial blood to venous plexuses deep within their bodies. Female manatees also possess hypogastric fossae and venous structures similar to those found in male manatees. The ovaries, uterine tubes, and distal tips of the uterine horns are located in the hypogastric fossae. We suggest that the thermovascular structures we describe also prevent hypothermic insult to female manatee reproductive tissues. The venous structures in manatees are functionally similar to structures associated with reproductive thermoregulation in cetaceans and phocid seals. Thus, these thermovascular structures appear to be convergent morphological adaptations that occur in three clades of diving mammals with independent evolutionary histories. PMID:11745089

  8. Gross and microscopic observations on the lingual structure of the Florida Manatee Trichechus manatus latirostris.

    Science.gov (United States)

    Levin, M J; Pfeiffer, C J

    2002-10-01

    The tongue of the Florida manatee (Trichechus manatus latirostris) was studied macroscopically, light and electron microscopically. The tongue was slender, muscular and firmly fixed in the oral cavity; only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral tongue. Multiple raised, round fungiform-like papillae were distributed over most of the dorsum. Typical fungiform papillae were restricted to the lateral margins of the tongue. Foliate papillae, presenting as multi-fossulate openings, were noted on the caudolateral margins. Open pits were located on the dorsocaudal surface and lateral walls. Microscopic examination showed that most of the lingual dorsum was covered with a thick stratified squamous epithelium. Open pits led to well-developed mucous salivary glands. Glands within the foliate papillae were mostly mucous, although some seromucous glands were present. Taste buds were restricted to the epithelium of the foliate papillae. Throughout the tongue, striated muscle was abundant below the epithelium. Blood vessels, lymph channels and nerve fibres were freely distributed throughout the intermuscular stroma. Nerve fibres reacted positively with neurone specific enolase (NSE) antibody throughout the tongue, including nerve bundles, glands and taste buds. Clear to translucent vacuoles were found juxtaposed to nuclei in the stratum spinosum in the foliate papillae epithelium. PMID:12484420

  9. Anatomic Considerations on the Middle Ear in Dog

    Directory of Open Access Journals (Sweden)

    Carmen Berghes

    2010-05-01

    Full Text Available Purpose of this study is to explain some aspects of middle ear anatomy in dog. The study was conducted on five dog skulls (different ages from common, large size dogs. The skulls were processed by maceration and submitted to a treatment of mechanical cleaning with perhydrol. The temporal bone was collected first; the external wall was opened carefully to study the tympanic cavity. The ossicles were collected separately and subsequently described. From research carried promontory appears as an elongated projection that separates the oval window and round window. Vestibular window is oval or slightly ovoid shape of a hole, located dorso-medially to the promontory, which communicates with the middle ear vestibule. Cochlearia window appears as a round or circular hole located caudo-lateral to the promontory . it is blocked by a membrane called the tympanum secondary, cavity separating the ramp of the snail. In the ventro-oral cavity openings ductus faringo tympanicum. The osicules sound represented by hammer, anvil and stirrup are articulated with each other and form a chain as a link between the eardrum and vestibular window. Bones are driven by two muscles: the tensor muscle and muscle stirrup eardrum is very thin. osicules ear are relatively large and resemble those of humans. Lenticular bone is the lenticular process of the long arm of anvile.

  10. A songbird forebrain area potentially involved in auditory discrimination and memory formation

    Indian Academy of Sciences (India)

    Raphael Pinaud; Thomas A Terleph

    2008-03-01

    Songbirds rely on auditory processing of natural communication signals for a number of social behaviors, including mate selection, individual recognition and the rare behavior of vocal learning – the ability to learn vocalizations through imitation of an adult model, rather than by instinct. Like mammals, songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals. Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (subfields L1, L2 and L3), the caudomedial and caudolateral mesopallium (CMM and CLM, respectively) and the caudomedial nidopallium (NCM). This review focuses on NCM, an auditory area previously proposed to be analogous to parts of the primary auditory cortex in mammals. Stimulation of songbirds with auditory stimuli drives vigorous electrophysiological responses and the expression of several activity-regulated genes in NCM. Interestingly, NCM neurons are tuned to species-specific songs and undergo some forms of experience-dependent plasticity in-vivo. These activity-dependent changes may underlie long-term modifications in the functional performance of NCM and constitute a potential neural substrate for auditory discrimination. We end this review by discussing evidence that suggests that NCM may be a site of auditory memory formation and/or storage.

  11. Efferent and afferent connections of the olfactory bulb and prepiriform cortex in the pigeon (Columba livia).

    Science.gov (United States)

    Atoji, Yasuro; Wild, J Martin

    2014-06-01

    Although olfaction in birds is known to be involved in a variety of behaviors, there is comparatively little detailed information on the olfactory brain. In the pigeon brain, the olfactory bulb (OB) is known to project to the prepiriform cortex (CPP), piriform cortex (CPi), and dorsolateral corticoid area (CDL), which together are called the olfactory pallium, but centrifugal pathways to the OB have not been fully explored. Fiber connections of CPi and CDL have been reported, but those of other olfactory pallial nuclei remain unknown. The present study examines the fiber connections of OB and CPP in pigeons to provide a more detailed picture of their connections using tract-tracing methods. When anterograde and retrograde tracers were injected in OB, projections to a more extensive olfactory pallium were revealed, including the anterior olfactory nucleus, CPP, densocellular part of the hyperpallium, tenia tecta, hippocampal continuation, CPi, and CDL. OB projected commissural fibers to the contralateral OB but did not receive afferents from the contralateral olfactory pallium. When tracers were injected in CPP, reciprocal ipsilateral connections with OB and nuclei of the olfactory pallium were observed, and CPP projected to the caudolateral nidopallium and the limbic system, including the hippocampal formation, septum, lateral hypothalamic nucleus, and lateral mammillary nucleus. These results show that the connections of OB have a wider distribution throughout the olfactory pallium than previously thought and that CPP provides a centrifugal projection to the OB and acts as a relay station to the limbic system.

  12. Connectivity and neurochemistry of the commissura anterior of the pigeon (Columba livia).

    Science.gov (United States)

    Letzner, Sara; Simon, Annika; Güntürkün, Onur

    2016-02-01

    The anterior commissure (AC) and the much smaller hippocampal commissure constitute the only interhemispheric pathways at the telencephalic level in birds. Since the degeneration study from Zeier and Karten (), no detailed description of the topographic organization of the AC has been performed. This information is not only necessary for a better understanding of interhemispheric transfer in birds, but also for a comparative analysis of the evolution of commissural systems in the vertebrate classes. We therefore examined the fiber connections of the AC by using choleratoxin subunit B (CTB) and biotinylated dextran amine (BDA). Injections into subareas of the arcopallium and posterior amygdala (PoA) demonstrated contralateral projection fields within the anterior arcopallium (AA), intermediate arcopallium (AI), PoA, lateral, caudolateral and central nidopallium, dorsal and ventral mesopallium, and medial striatum (MSt). Interestingly, only arcopallial and amygdaloid projections were reciprocally organized, and all AC projections originated within a rather small area of the arcopallium and the PoA. The commissural neurons were not GABA-positive, and thus possibly not of an inhibitory nature. In sum, our neuroanatomical study demonstrates that a small group of arcopallial and amygdaloid neurons constitute a wide range of contralateral projections to sensorimotor and limbic structures. Different from mammals, in birds the neurons that project via the AC constitute mostly heterotopically organized and unidirectional connections. In addition, the great majority of pallial areas do not participate by themselves in interhemispheric exchange in birds. Instead, commissural exchange rests on a rather small arcopallial and amygdaloid cluster of neurons.

  13. Bird brains and tool use: beyond instrumental conditioning.

    Science.gov (United States)

    Striedter, Georg F

    2013-01-01

    Few displays of complex cognition are as intriguing as nonhuman tool use. Long thought to be unique to humans, evidence for tool use and manufacture has now been gathered in chimpanzees, dolphins, and elephants. Outside of mammals, tool use is most common in birds, especially in corvids and parrots. The present paper reviews the evidence for avian tool use, both in the wild and in laboratory settings. It also places this behavioral evidence in the context of longstanding debates about the kinds of mental processes nonhumans can perform. Descartes argued that animals are unable to think because they are soulless machines, incapable of flexible behavior. Later, as human machines became more sophisticated and psychologists discovered classical and instrumental conditioning, skepticism about animal thinking decreased. However, behaviors that involve more than simple conditioning continued to elicit skepticism, especially among behaviorists. Nonetheless, as reviewed here, strong behavioral data now indicate that tool use in some birds cannot be explained as resulting entirely from instrumental conditioning. The neural substrates of tool use in birds remain unclear, but the available data point mainly to the caudolateral nidopallium, which shares both functional and structural features with the mammalian prefrontal cortex. As more data on the neural mechanisms of complex cognition in birds accrue, skepticism about those mental capacities should continue to wane. PMID:23979456

  14. Evaluation of the marsh deer stifle joint by imaging studies and gross anatomy.

    Science.gov (United States)

    Shigue, D A; Rahal, S C; Schimming, B C; Santos, R R; Vulcano, L C; Linardi, J L; Teixeira, C R

    2015-12-01

    This study aimed to evaluate the stifle joint of marsh deer using imaging studies and in comparison with gross anatomy. Ten hindlimbs from 5 marsh deer (Blastocerus dichotomus) were used. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in each stifle joint. Two hindlimbs were dissected to describe stifle gross anatomy. The other limbs were sectioned in sagittal, dorsal or transverse planes. In the craniocaudal radiographic view, the lateral femoral condyle was broader than the medial femoral condyle. The femoral trochlea was asymmetrical. Subsequent multiplanar reconstruction revealed in the cranial view that the external surface of the patella was roughened, the medial trochlea ridge was larger than the lateral one, and the extensor fossa at the lateral condyle was next to the lateral ridge. The popliteal fossa was better visualized via the lateral view. Sagittal MRI images identified lateral and medial menisci, caudolateral and craniomedial bundles of cranial cruciate ligament, caudal cruciate ligament, patellar ligament and common extensor tendon. In conclusion, the marsh deer stifle presents some anatomical characteristics of the ovine stifle joint. PMID:25376635

  15. Abnormalities of the axial and proximal appendicular skeleton in adults with Laron syndrome (growth hormone insensitivity)

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, L.; Konen, O.; Schwarz, M.; Horev, G. [Schneider Children' s Medical Center of Israel, Imaging Department, Petah Tiqwa (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Siegel, Y. [Rabin Medical Center, Imaging Department, Petah Tiqwa (Israel); Jackson Memorial Hospital, Department of Radiology, Thoracic Section, Miami, FL (United States); Hershkovitz, I. [Tel Aviv University, Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv (Israel); Laron, Z. [Schneider Children' s Medical Center of Israel, Endocrinology and Diabetes Research Unit, Petah Tiqwa (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel)

    2008-02-15

    To investigate abnormalities in the skeleton (with the exclusion of the skull, cervical spine, hands and feet) in patients with Laron syndrome, who have an inborn growth hormone resistance and congenital insulin-like growth factor-1 (IGF-1) deficiency. The study group was composed of 15 untreated patients with Laron syndrome (seven male and eight female) aged 21-68 years. Plain films of the axial and appendicular skeleton were evaluated retrospectively for abnormalities in structure and shape. The cortical width of the long bones was evaluated qualitatively and quantitatively (in the upper humerus and mid-femur), and the cortical index was calculated and compared with published references. Measurements were taken of the mid-anteroposterior and cranio-caudal diameters of the vertebral body and spinous process at L3, the interpedicular distance at L1 and L5, and the sacral slope. Thoracic and lumbar osteophytes were graded on a 5-point scale. Values were compared with a control group of 20 healthy persons matched for age. The skeleton appeared small in all patients. No signs of osteopenia were visible. The cortex of the long bones appeared thick in the upper limbs in 11 patients and in the lower limbs in four. Compared with the reference values, the cortical width was thicker than average in the humerus and thinner in the femur. The vertebral diameters at L3 and the interpedicular distances at L1 and L5 were significantly smaller in the patients than in the control subjects (P < 0.001); however, at L5 the canal was wider, relative to the vertebral body. The study group had a higher rate of anterior osteophytes in the lumbar spine than the controls had, and their osteophytes were also significantly larger. In the six patients for whom radiographs of the upper extremity in its entirety were available on one film, the ulna appeared to be rotated. In one 22-year-old man, multiple epiphyses were still open. Congenital IGF-1 deficiency leads to skeletal abnormalities

  16. Progression of stifle osteoarthrosis following reconstruction of the cranial cruciate ligament in 21 dogs

    International Nuclear Information System (INIS)

    Twenty-one dogs that had intraarticular reconstruction of the cranial cruciate ligament were examined clinically and radiographically to assess limb function and determine if there had been progression of osteoarthrosis in the affected stifle joints. The interval between surgery and follow-up examination varied from 1 to 47 months, mean = 14.9 +/-12.9 months standard deviation. Clinical variables that were assessed included lameness, palpable joint instability, articular crepitus, and joint swelling. Radiographic features that were evaluated included soft-tissue swelling/joint effusion, subchondral sclerosis, periarticular osteophyte and enthesiophyte formation, remodeling of femoral and tibial condyles, and resorptive changes in the intercondyloid fossa. The owners of all 21 dogs believed that the operation had improved their dog's condition because the frequency of lameness had decreased. However, palpable instability, crepitus, and joint swelling were detected frequently during physical examinations. Radiographs documented progression of osteoarthrosis in the operated upon stifle joints of all 21 dogs

  17. A tomographic study of positional and bony changes in the temporomandibular joint following orthognathic surgery

    Energy Technology Data Exchange (ETDEWEB)

    Song, Nam Kyu; Kim Min Suk; Koh, Kwang Joon [Dept. of Oral Radiology, College of Dentistry, Chonpook National University, Chonju (Korea, Republic of)

    1992-08-15

    The purpose of this study was to aid in the evaluation of prognosis of temporomandibular joint following orthognathic surgery. For this study, 20 patients (40 TMJ) who undergone orthognathic surgery were examined. Preoperative and postoperative tomograms of TMJ were taken. And the subjects were divided into 3 groups according to postoperative periods. The obtained results were as follows : 1. There were no significant differences between preoperative and postoperative changes in joint spaces in each group and between groups (P<0.05). 2. There were no significant differences between preoperative and postoperative ratio of joint spaces (P<0.05).3. There were no significant differences between preoperative and postoperative changes in the range of motion of condylar head (P<0.05). 4. The bony changes of condylar head were observed in 14 (35%) condyles (6 erosion, 2 flattening, 5 double contour, 1 osteophyte).

  18. Osteoarthritis of the knee after meniscal resection

    DEFF Research Database (Denmark)

    Paradowski, P T; Lohmander, L S; Englund, M

    2016-01-01

    OBJECTIVE: To determine prevalence, incidence and progression of radiographic knee osteoarthritis (OA) in a cohort of subjects with previous meniscectomy. METHODS: We assessed 221 subjects (177 men and 44 women) with weight bearing knee radiography twice (assessment A and B) with a follow-up time...... Kellgren and Lawrence grade 2 or worse. RESULTS: At assessment A, we found tibiofemoral radiographic OA in 107 subjects' index knee (48%) of which 41 subjects (38%) had bilateral tibiofemoral OA. At assessment B, the corresponding figures were 151 (68%) and 71 (32%). At assessment A, we found...... patellofemoral OA in 32 subjects' index knee (14%) of which 11 (34%) had bilateral patellofemoral OA. At assessment B, the corresponding figures were 51 (23%) and 19 (37%). There was an increase of the sum of joint space narrowing (JSN) and osteophyte grades in the tibiofemoral joint of 144 subjects' index knee...

  19. PROGRESSIVE SYRINGOHYDROMYELIA AND DEGENERATIVE AXONOPATHY IN A BOBCAT (LYNX RUFUS) FOLLOWING SURGICAL CORRECTION OF A CHIARI-LIKE MALFORMATION.

    Science.gov (United States)

    Sadler, Ryan; Schumacher, Juergen; Ramsay, Edward; McCleery, Brynn; Baine, Katherine; Thomas, William; Nobrega-Lee, Michelle; Henry, George A; Newman, Shelley J

    2016-03-01

    A 3-yr-old male captive bobcat (Lynx rufus) presented with chronic ataxia and right-sided head tilt. Magnetic resonance imaging (MRI) revealed cerebellar crowding and compression consistent with Chiari-like malformation. The clinical signs did not improve after surgical occipital craniectomy, and 2 mo postoperatively a second MRI showed hydromyelia and continued cerebellar compression. The bobcat was euthanized, and necropsy showed chronic focal cerebellar herniation and chronic multifocal atlanto-occipital joint osteophyte proliferation. Histology confirmed the presence of a thick fibrous membrane along the caudal aspect of the cerebellar vermis, suggestive of postoperative adhesions, and axonal degeneration of the cervical spinal cord, even in sections without a central canal lesion. These lesions appear to have been complications associated with surgical correction of the Chiari-like malformation.

  20. MR findings in knee osteoarthritis

    International Nuclear Information System (INIS)

    Knee osteoarthritis (OA) is a leading cause of disability. Recent advances in drug discovery techniques and improvements in understanding the pathophysiology of osteoarthritic disorders have resulted in an unprecedented number of new therapeutic agents. Of all imaging modalities, radiography has been the most widely used for the diagnosis and management of the progression of knee OA. Magnetic resonance imaging is a relatively recent technique and its applications to osteoarthritis have been limited. Compared with conventional radiography, MR imaging offers unparalleled discrimination among articular soft tissues by directly visualizing all components of the knee joint simultaneously and therefore allowing the knee joint to be evaluated as a whole organ. In this article we present the MR findings in knee OA including cartilage abnormalities, osteophytes, bone edema, subarticular cysts, bone attrition, meniscal tears, ligament abnormalities, synovial thickening, joint effusion, intra-articular loose bodies, and periarticular cysts. (orig.)

  1. Hemochromatosis: abnormalities of bones and joints: a case report and literature review

    International Nuclear Information System (INIS)

    The authors report a case of a 49 years-old male patient with emphasis in the arthropathy of hemochromatosis. The arthropathy was the first manifestation: the patient had been complaining of pain on the right hip for eight years. The other specific clinical manifestations: diabetes, abnormal pigmentation appeared after six years. The roentgenographic features of bone and joint involvement include abnormalites at metacarpophalangeal joints with osteophytes on the metacarpal heads and in the hip, joint space narrowing, was seen. In the knee involvement is characterized by subchondral cyst and osteophytosis. Laboratory analysis are: serum iron = 191 mg/dl (normal value: 50-150 mg/dl), ferritin > 400 ng/ml (normal value: 42-26 ng/ml). Iron within the parenchymal cells of the liver cirrhosis was detected by hepatic biopsy. Hemochromatosis was pathologically characterized by tissue damage produced by iron deposition. (author)

  2. Comparison of acetabular reamings during hip resurfacing versus uncemented total hip arthroplasty.

    LENUS (Irish Health Repository)

    Brennan, S A

    2009-04-01

    PURPOSE: To compare the quantity of bone removed from the acetabulum during resurfacing hip arthroplasty versus uncemented total hip arthroplasty (THA). METHODS: 62 consecutive patients with osteoarthritis of the hip were prospectively studied. 24 men and 7 women aged 40 to 86 (mean, 59) years underwent Birmingham hip resurfacing. 13 men and 18 women aged 34 to 88 (mean, 61) years underwent uncemented THA using the trident acetabular cup. Obese elderly women at risk of femoral neck fracture and patients with large subchondral pseudocysts or a history of avascular necrosis of the femoral head were assigned to uncemented THA. Acetabular reamings were collected; marginal osteophytes were not included. The reamings were dehydrated, defatted, and weighed. RESULTS: The mean weight of acetabular reamings was not significantly different between patients undergoing hip resurfacing and uncemented THA (p=0.57). CONCLUSION: In hip resurfacing, the use of an appropriately small femoral component avoids oversizing the acetabular component and removal of excessive bone stock.

  3. Diet-Intestinal Microbiota Axis in Osteoarthritis: A Possible Role.

    Science.gov (United States)

    Li, Yusheng; Luo, Wei; Deng, Zhenhan; Lei, Guanghua

    2016-01-01

    Intestinal microbiota is highly involved in host physiology and pathology through activity of the microbiome and its metabolic products. Osteoarthritis (OA) is a common form of arthritis characterized by articular cartilage destruction and osteophyte formation. Although various person-level risk factors, such as age, sex, and obesity, have been proposed for the pathogenesis of OA, the underlying links between these person-level factors and OA are still enigmatic. Based on the current understanding in the crosstalk between intestinal microbiota and these risk factors, intestinal microbiota could be considered as a major hidden risk factor that provides a unifying mechanism to explain the involvement of these person-level risk factors in OA. PMID:27610004

  4. Flexor Carpi Radialis to Palmaris Longus Tendon Transfer for Spontaneous Rupture of the Flexor Carpi Radialis Tendon-A Review of an Uncommon Finding and Surgical Technique for Operative Correction.

    Science.gov (United States)

    Shearin, Jonathan Winkworth; Walters, Brian; Yang, S Steven

    2016-10-01

    Spontaneous ruptures of the flexor carpi radialis tendon (FCR) are rare and associated with systemic inflammatory diseases, localized tendinopathy related to scaphotrapezial-trapezoidal arthritis, or chronic immunosuppression from corticosteroids. While most cases do not require operative intervention, some patients develop weakness, impaired range of motion, and persistent pain. Previously reported surgical options include synovectomy, tendon stump resection, and osteophyte removal. We describe a surgical technique for patients with persistent symptomatology following FCR rupture in which the FCR is transposed end-to-side to the palmaris longus tendon. Three cases using this technique are presented with follow-up of 4-9 months that were collected at Lenox Hill Hospital. All three patients did well regarding specific outcome measures: grip strength, range of motion, and functional activity. FCR transfer to palmaris is an alternative to other surgical options for the spontaneous rupture of the FCR tendon in patients who remain symptomatic despite a course of non-operative therapy. PMID:27595965

  5. [The appearances of chondropathia patellae on plain films (author's transl)].

    Science.gov (United States)

    Schumacher, K A; Glöckler, W T; Mutschler, W; Rittmeyer, K

    1979-12-01

    The ability to diagnose chondropathia patellae on plain radiographs was studied in 64 patients in whom the disease had been confirmed either by operation or arthroscopy. All cases of stage III chondropathia were diagnosable by radiological examination; in stage I, 67%, and in stage II, 73% could be diagnosed. The diagnosis depends on the co-existence of marginal irregularities, irregularities of the subchondral bone lamellae, spotty diffuse demineralisation, marginal osteophytes, irregularities at the insertion of the quadriceps tendon and soft tissue changes such as joint effusions. These changes are best identified on the so-called "defilée" view. Disalignment of the axis of the patella and post-traumatic defects are of particular importance for the development of chondropathia, but in the present clinical material, the existence of dysplasia of the patella or of the femoral condyle was not associated with a demonstrable increase of chondromalacia.

  6. Pathophysiology of osteoarthritis: perspectives

    Directory of Open Access Journals (Sweden)

    O. Viapiana

    2011-09-01

    Full Text Available Osteoarthritis is generally considered a degenerative disorder driven by mechanical alteration of joint cartilage, with the bone changes being reactive to cartilage changes. According to this pathogenetic mechanism the only strategy to prevent osteoarthritis should be based on the so-called “chondro-protective agents”. However, a number of recent finding suggests that both the initiation and the progression of the disease is driven by subchondral bone changes reactive to mechanical microdamages. These increase osteoblastic activity at the “tide-mark” with consequent enlargement of the epiphyses and osteophyte formation. The increased bone turnover is secondary to overproduction of cytokines that diffuse to cartilage tissue, where they suppress condrocyte activity and activate metallo-proteases. Preliminary observational finding and experimental data showed that inhibitors of bone turnover might slow osteoarthritis progression. The pathogenetic hypothesis for osteoarthritis illustrated here provides the rational for a new therapeutic approach to the disease.

  7. Surgical Correction of Patellar Luxation in a Rabbit

    Directory of Open Access Journals (Sweden)

    J. Riggs

    2013-01-01

    Full Text Available A two-and-a-half-year-old giant lop-eared rabbit, weighing 5.1 kg, presented with a one-month history of intermittent right hind limb lameness. The limb locked in extension during hopping. On examination, a grade-2 medial patellar luxation of the right hind was diagnosed, with associated stifle joint swelling. Radiographic findings of the right stifle comprised periarticular osteophyte formation consistent with mild degenerative joint disease and joint effusion. Surgical correction involving right trochlear wedge recession sulcoplasty and lateral imbrication was carried out to stabilise the patella in the trochlear groove. The right hind limb lameness resolved, and the patella was stable at a 6-month postoperative examination. One year postoperatively, the right patella was luxating again concurrent with bilateral stifle effusions. Euthanasia was performed twenty months after surgery due to recurrent lameness in the right hind limb.

  8. Carpal boss in chronic wrist pain and its association with partial osseous coalition and osteoarthritis - A case report with focus on MRI findings

    Directory of Open Access Journals (Sweden)

    Feng Poh

    2015-01-01

    Full Text Available The carpal boss is a bony prominence at the dorsal aspect of the 2 nd and/or 3 rd carpometacarpal joint, which has been linked to various etiologies, including trauma, os styloideum, osteophyte formation, and partial osseous coalition. It may result in symptoms through secondary degeneration, ganglion formation, bursitis, or extensor tendon abnormalities by altered biomechanics of wrist motion. We present a case of symptomatic carpal boss with the finding of a partial osseous coalition at the 2 nd carpometacarpal (metacarpal-trapezoid joint and highlight the magnetic resonance imaging (MRI findings of carpal boss impingement and secondary osteoarthritis. To the best of our knowledge, there is no report in the literature describing the imaging findings of partial osseous coalition and degenerative osteoarthritis in relation to carpal boss.

  9. The degenerative spine: pattern recognition and guidelines to image interpretation.

    Science.gov (United States)

    Parizel, P M; Van Hoyweghen, A J L; Bali, A; Van Goethem, J; Van Den Hauwe, L

    2016-01-01

    Degenerative disease of the spine, in the form of intervertebral disc degeneration and bony growth, causing osteophytes and impinging upon the spinal canal and neural foramina, is the most frequent disorder affecting the spine. In this chapter we first discuss briefly the indications for computed tomography or magnetic resonance imaging in suspected degenerative spine disease. We then describe changes of disc height, signal intensity, and disc contour with aging and repeated microtrauma, as well as the imaging techniques most appropriate to image them. A grading system for lumbar disc changes is provided. Stenosis of the canal and neural foramina is reviewed next, concluding with a description of degenerative changes affecting the vertebral endplates and bone marrow.

  10. Osteoid osteoma simulating an osteocartilaginous exostosis

    Energy Technology Data Exchange (ETDEWEB)

    Marinelli, A.; Giacomini, S.; Bianchi, G.; Pellacani, A.; Mercuri, M. [Rizzoli Orthopedic Institute, University of Bologna, Via Pupilli 1, 40127, Bologna (Italy); Bertoni, F. [Pathology Department, Rizzoli Orthopedic Institute, University of Bologna (Italy)

    2004-03-01

    We describe a case of osteoid osteoma in the tibia of a 3-year-old patient who presented with a clinical and radiographic picture that suggested an exostosis. The formation of osteoid osteoma with a radiographic picture similar to that of osteophytes or exostosis has been previously documented only rarely. The authors hypothesize that the exostosis-like formation observed was actually the calcification of soft tissues that formed after the intense periosteal inflammatory reaction caused by the osteoid osteoma. As a result of its peculiar clinical and radiographic presentation, diagnosis of this lesion was delayed. Being located close to the medial growth plate of the tibia, it caused lengthening of the limb with a pronounced valgus deviation of the knee. An excisional biopsy provided histological evidence, clinical resolution and immediate pain relief, but incomplete resolution of the valgus deformity of the knee. (orig.)

  11. Advances in the Pathogenesis, Diagnosis and Treatment of Bow Hunter's Syndrome: A Comprehensive Review of the Literature.

    Science.gov (United States)

    Duan, Guangxin; Xu, Jiaping; Shi, Jijun; Cao, Yongjun

    2016-06-01

    Bow hunter's syndrome (BHS), also known as rotational vertebral artery (VA) occlusion syndrome, is a rare yet treatable type of symptomatic vertebrobasilar insufficiency resulting from mechanical occlusion or stenosis of the VA during head and neck rotation or extension. The symptoms of BHS range from transient vertigo to posterior circulation stroke. The underlying pathology is dynamic stenosis or compression of the VA by abnormal bony structures with neck rotation or extension in many cases, such as osteophyte, disc herniation, cervical spondylosis, tendinous bands or tumors. Imaging approaches, such as Doppler sonography, computed tomography and angiography, as well as magnetic resonance imaging and angiography, are widely used in the diagnosis and evaluation of this syndrome. Digital subtraction angiography with head rotation remains the gold standard diagnostic method. Conservative management, surgery and endovascular procedures are the three major treatment methods for BHS, whereas some symptomatic patients may need operative treatment including surgery and endovascular procedures when conservative management is not adequate. PMID:27610119

  12. The degenerative spine: pattern recognition and guidelines to image interpretation.

    Science.gov (United States)

    Parizel, P M; Van Hoyweghen, A J L; Bali, A; Van Goethem, J; Van Den Hauwe, L

    2016-01-01

    Degenerative disease of the spine, in the form of intervertebral disc degeneration and bony growth, causing osteophytes and impinging upon the spinal canal and neural foramina, is the most frequent disorder affecting the spine. In this chapter we first discuss briefly the indications for computed tomography or magnetic resonance imaging in suspected degenerative spine disease. We then describe changes of disc height, signal intensity, and disc contour with aging and repeated microtrauma, as well as the imaging techniques most appropriate to image them. A grading system for lumbar disc changes is provided. Stenosis of the canal and neural foramina is reviewed next, concluding with a description of degenerative changes affecting the vertebral endplates and bone marrow. PMID:27430442

  13. Impingement syndrome of the shoulder

    International Nuclear Information System (INIS)

    The impingement syndrome is a clinical entity characterized by shoulder pain due to primary or secondary mechanical irritation of the rotator cuff. The primary factors for the development of impingement are a curved or hook-shaped anterior acromion as well as subacromial osteophytes, which may lead to tearing of the supraspinatus tendon. Secondary impingement is mainly caused by calcific tendinopathy, glenohumeral instability, os acromiale and degenerative changes of the acromioclavicular joint. Conventional radiographs are initially obtained, mainly for evaluation of the bony structures of the shoulder. If available, sonography can be used for detection of lesions and tears of the rotator cuff. Finally, MR-imaging provides detailed information about the relationship of the acromion and the acromioclavicular joint to the rotator cuff itself. In many cases however, no morphologic cause for impingement syndrome can be found. While patients are initially treated conservatively, chronic disease usually requires surgical intervention. (orig.)

  14. Impingement syndrome of the ankle following supination external rotation trauma: MR imaging findings with arthroscopic correlation

    Energy Technology Data Exchange (ETDEWEB)

    Schaffler, Gottfried J. [Department of Radiology, University of California San Francisco, 350 Parnassus Avenue, Suite 150, San Francisco, CA 94117 (United States); Department of Radiology, University Hospital Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Tirman, Phillip F.J.; Stoller, David W. [San Francisco Magnetic Resonance Center, 3333 California Street, Suite 105, San Francisco, CA 94118 (United States); Genant, Harry K. [Department of Radiology, University of California San Francisco, 350 Parnassus Avenue, Suite 150, San Francisco, CA 94117 (United States); Ceballos, Cecar; Dillingham, Michael F. [Sports Orthopedics and Rehabilitation, 2884 Sand Hill Rd., Suite 110, Menlo Park, CA 94025 (United States)

    2003-06-01

    Our objective was to identify MR imaging findings in patients with syndesmotic soft tissue impingement of the ankle and to investigate the reliability of these imaging characteristics to predict syndesmotic soft tissue impingement syndromes of the ankle. Twenty-one ankles with chronic pain ultimately proven to have anterior soft tissue impingement syndrome were examined by MR imaging during January 1996 to June 2001. The MR imaging protocol included sagittal and coronal short tau inversion recovery (STIR), sagittal T1-weighted spin echo, axial and coronal proton-density, and T2-weighted spin-echo sequences. Nineteen ankles that underwent MR imaging during the same period of time and that had arthroscopically proven diagnosis different than impingement syndrome served as a control group. Fibrovascular scar formations distinct from the syndesmotic ligaments possibly related to syndesmotic soft tissue impingement were recorded. Arthroscopy was performed subsequently in all patients and was considered the gold standard. The statistical analysis revealed an overall frequency of scarred syndesmotic ligaments of 70% in the group with ankle impingement. Fibrovascular scar formations distinct from the syndesmotic ligaments presented with low signal intensity on T1-weighted images and remained low to intermediate in signal intensity on T2-weighted MR imaging. Compared with arthroscopy, MR imaging revealed a sensitivity of 89%, a specificity of 100%, and a diagnostic accuracy of 93% for scarred syndesmotic ligaments. The frequency of scar formation distinct from the syndesmotic ligaments in patients with impingement syndrome of the ankle was not statistically significantly higher than in the control group. In contrast to that, anterior tibial osteophytes and talar osteophytes were statistically significantly higher in the group with anterior impingement than in the control group. Conventional MR imaging was found to be insensitive for the diagnosis of syndesmotic soft tissue

  15. 'Hard discs' associated with lumbar disc herniation: CT analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Il Kwon; Bang, Dae Hong; Yim, Jung Ik; Lee, Jae Mun; Bahk, Yong Whee [Catholic University Medical College, Seoul (Korea, Republic of)

    1989-02-15

    Thirty cases showing hard discs were collected from 206 consecutive cases of posterior disk herniation during the past one and a half years period. According to the shape of hard disk and the presence of marginal bone defect (MBD) of vertebral end plate, 30 cases could be categorized into 4 distinct groups. They were small hard disc with focal MBD (group 1), large hard disc with broad based MBD (group 2), hard disc separated from vertebral body without MBD (group 3) and hard disc fused with vertebral body without MBD (group 4). There were 14 patients in group 1. In all but one case, the hard disc and MBDs were located at the paramedial aspect of the posterior margin of the end plate. Ten (76.9%) of these had Schmorl's nodes and these were considered to represented an avulsion from the weakened bone margin as the disk herniated acutely. The posterior longitudinal ligament seemed to have prevented detachment of the bony fragment. Group 2 included 2 patients and CT findings as well as plain X-ray features were identical to a limbus vertebra. This was considered to represent passive displacement of bony fragment by the intravertebral herniation of the disk. Nine patients belonged to group 3 and represent dystrophic calcifications of herniated disk. Group 4 included 5 patients and was disclosed as a simple osteophyte. From our study, it was concluded; (1) that the hard disc seen in lumbar CT scan was probably the results of the detachment of a bone fragment from the vertebral end plate which has an underlying weak area due to the herniated disc as well as a calcification or osteophyte formation and (2) specific terms (avulsed fragment, limbus vertebra, calcification or spur formation) is more preferable to use than hard disc which is inaccurate.

  16. Radiographic assessment of the femorotibial joint of the CCLT rabbit experimental model of osteoarthritis

    Directory of Open Access Journals (Sweden)

    Collard Fabien

    2010-01-01

    Full Text Available Abstract Background The purposes of the study were to determine the relevance and validity of in vivo non-invasive radiographic assessment of the CCLT (Cranial Cruciate Ligament Transection rabbit model of osteoarthritis (OA and to estimate the pertinence, reliability and reproducibility of a radiographic OA (ROA grading scale and associated radiographic atlas. Methods In vivo non-invasive extended non weight-bearing radiography of the rabbit femorotibial joint was standardized. Two hundred and fifty radiographs from control and CCLT rabbits up to five months after surgery were reviewed by three readers. They subsequently constructed an original semi-quantitative grading scale as well as an illustrative atlas of individual ROA feature for the medial compartment. To measure agreements, five readers independently scored the same radiographic sample using this atlas and three of them performed a second reading. To evaluate the pertinence of the ROA grading scale, ROA results were compared with gross examination in forty operated and ten control rabbits. Results Radiographic osteophytes of medial femoral condyles and medial tibial condyles were scored on a four point scale and dichotomously for osteophytes of medial fabella. Medial joint space width was scored as normal, reduced or absent. Each ROA features was well correlated with gross examination (p s = 0.68 and rs = 0.58, p s = 0.64, p Conclusion Non-invasive in vivo radiography of the rabbit femorotibial joint is feasible, relevant and allows a reproducible grading of experimentally induced OA lesion. The radiographic grading scale and atlas presented could be used as a template for in vivo non invasive grading of ROA in preclinical studies and could allow future comparisons between studies.

  17. Impingement syndrome of the ankle following supination external rotation trauma: MR imaging findings with arthroscopic correlation

    International Nuclear Information System (INIS)

    Our objective was to identify MR imaging findings in patients with syndesmotic soft tissue impingement of the ankle and to investigate the reliability of these imaging characteristics to predict syndesmotic soft tissue impingement syndromes of the ankle. Twenty-one ankles with chronic pain ultimately proven to have anterior soft tissue impingement syndrome were examined by MR imaging during January 1996 to June 2001. The MR imaging protocol included sagittal and coronal short tau inversion recovery (STIR), sagittal T1-weighted spin echo, axial and coronal proton-density, and T2-weighted spin-echo sequences. Nineteen ankles that underwent MR imaging during the same period of time and that had arthroscopically proven diagnosis different than impingement syndrome served as a control group. Fibrovascular scar formations distinct from the syndesmotic ligaments possibly related to syndesmotic soft tissue impingement were recorded. Arthroscopy was performed subsequently in all patients and was considered the gold standard. The statistical analysis revealed an overall frequency of scarred syndesmotic ligaments of 70% in the group with ankle impingement. Fibrovascular scar formations distinct from the syndesmotic ligaments presented with low signal intensity on T1-weighted images and remained low to intermediate in signal intensity on T2-weighted MR imaging. Compared with arthroscopy, MR imaging revealed a sensitivity of 89%, a specificity of 100%, and a diagnostic accuracy of 93% for scarred syndesmotic ligaments. The frequency of scar formation distinct from the syndesmotic ligaments in patients with impingement syndrome of the ankle was not statistically significantly higher than in the control group. In contrast to that, anterior tibial osteophytes and talar osteophytes were statistically significantly higher in the group with anterior impingement than in the control group. Conventional MR imaging was found to be insensitive for the diagnosis of syndesmotic soft tissue

  18. Comparison of conventional panoramic radiography and panoramic digital subtraction radiography in detection of simulated lesions of mandibular condyle

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2008-12-01

    Full Text Available "n  "nBackground and Aim: Digital subtraction Radiography (DSR is a method of accurate assessing condylar head changes. several studies have been carried out in applying DSR in dentistry, however there is a few number of studies in efficacy of DSR method in assesment of condylar head changes, The aim of this study was to compare panoramic radiography and DSR detecting simulated lesions of the mandibular condyl. "nMaterials and Methods: this was a process reaserch study, in which two dry human skulls with no obvious temporomandibular joint pathology were used. Osteophytic lesions were simulated using three sizes of bone chips that were placed on the medial portion of anterior and superolateral aspects of the condyle. Osteolytic lesions were simulated making 1 and 2 mm holes using round burr in the central portion of anterior aspect and Lateral pole of the condyle. Panoramic radiographs were prepared with and without the lesions in place. These paired radiographs were digitized and digital- subtraction images of the original panoramic images were obtained. Eight observers evaluated 155 images of each modality for the presence or absence and the type of simulated lesions of the mandibular condyle. Sensitivity, specificity, reliability and measure of agreement were analyzed using kappa test and crossed tables and qualitative variables were assess by chi-square and fisher's Exact test. "nResults: Specificity of panoramic and DSR methods were 15.4% and 66.7% respectively. Sensitivity of panoramic and DSR methods were 61.1% and 80.6% for osteophytic lesions and 37.5% and 83.3% for Osteolytic lesions. The percentage of correct decisions made in DSR method was significantly more than conventional panoramic method (82.6% vs 41.9% (p<0.0001. "nConclusion: Based on the results of this study digital subtraction technique was significantly more accurate than the panoramic radiographs in detection of simulated lesions of the mandibular condyle.

  19. Nontraumatic bifid mandibular condyles in asymptomatic and symptomatic temporomandibular joint subjects

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Bong Hae; Jung, Yun Hoa [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2013-03-15

    This study was performed to determine the prevalence of bifid mandibular condyles (BMCs) in asymptomatic and symptomatic temporomandibular joint (TMJ) subjects with no traumatic history, and to assess their impact on clinical and radiographic manifestations of TMJ. A total of 3,046 asymptomatic and 4,378 symptomatic patients were included in the study. Cone-beam computed tomography (CBCT) images were reviewed for bifid condyles. T-tests were used to compare the frequency of BMCs when stratified by symptom, gender, and side. In BMC patients, the clinical features of pain and noise, osseous changes, and parasagittal positioning of the condyles were compared between the normally shaped condyle side and the BMC side using chi-squared tests. Fifteen (0.49%) asymptomatic and 22 (0.50%) symptomatic patients were found to have BMCs. Among the bilateral cases, the number of condyles were 19 (0.31%) and 25 (0.29%), respectively. No statistically significant differences were found between asymptomatic and symptomatic patients, between female and male patients, or between the right and left sides (p>0.05). Compared with the normally shaped condyle side, the BMC side showed no statistically significant differences in the distribution of pain and noise, parasagittal condylar position, or condylar osseous changes, with the exception of osteophytes. In the symptomatic group, osteophytes were found more frequently on the normally shaped condyle side than the BMC side (p<0.05). BMCs tended to be identified as an incidental finding. The presence of BMC would not lead to any TMJ symptoms or cause osseous changes.

  20. LECTURE ON ACUPUNCTURE PartⅠ Clinical Acupuncture Lecture Thirty-fiveCervical Spondylopathy

    Institute of Scientific and Technical Information of China (English)

    罗汀; 王卫; 徐力

    2004-01-01

    @@ Cervical spondylopathy, also known as cervical syndrome, is a commonly encountered disease in the middle-aged and elderly people. This disease mostly results from the retrograde affection of the cervical intervertebral disc and hyperosteogeny of the cervical vertebrae. This hyperplastic substance may stimulate and give rise to oppression to the surrounding spinal cord, nerve roots, blood vessels and sympathetic nerves, resulting in a series of symptoms as numbness, pain, etc. in the neck, shoulder and the upper limbs. The cervical vertebra of the human spine is smallest in the size, weakest in the strength, higher in the motor range and frequency, and bigger in the bearing of per unit area. Along with the increasing of people's age and the accumulated aftereffect of chronic and acute injury, the pulpiform nucleus of the cervical intervertebral disc presents retrograde affection, dehydration, bulge and rupture of the fibrous ring, narrowing of the intervertebral space, and reduction in the stability of cervical vertebrae due to injury and slackening of intervertebral ligaments to stretch and to induce compression upon periosteum. All these changes may lead to break of blood vessels to cause bleeding and hematoma. With the organization of hematoma and calcium salt deposit, osteophyte is formed at last. When the protruded intervertebral disc and hyperplastic osteophyte stimulate and oppress the surrounding spinal nerve root, vertebral artery or spinal cord, the resultant injury, aseptic inflammation, reactions after renovation, etc. will generate a series of clinical symptoms of cervical spondylopathy. In Western medicine, there are five types of cervical spondylopathy including stiff-neck type, nerve root type, spinal cord type, vertebral artery type and sympathetic nerve type. The stiff-neck type, nerve root type and vertebral artery type will be introduced in this article.

  1. Is physical activity, practiced as recommended for health benefit, a risk factor for osteoarthritis?

    Science.gov (United States)

    Lefèvre-Colau, Marie-Martine; Nguyen, Christelle; Haddad, Rebecca; Delamarche, Paul; Paris, Guillaume; Palazzo, Clémence; Poiraudeau, Serge; Rannou, François; Roren, Alexandra

    2016-06-01

    In this critical narrative review, we examine the role of physical activity (PA), recreational and elite sports in the development of knee/hip osteoarthritis (OA), taking into account the role of injury in this relationship. The process of article selection was unsystematic. Articles were selected on the basis of the authors' expertise, self-knowledge, and reflective practice. In the general adult population, self-reported diagnosis of knee/hip OA was not associated with low, moderate or high levels of PA. For studies using radiographic knee/hip OA as a primary outcome, the incidence of asymptomatic radiographic OA was higher for subjects with the highest quartile of usual PA than the least active subjects. The risk of incident radiographic knee/hip OA features was increased for subjects with a history of regular sports participation (for osteophyte formation but not joint space narrowing). This risk depended on the type of sport (team and power sports but not endurance and running), and certain conditions (high level of practice) were closely related to the risk of injury. The prevalence of radiographic OA was significantly higher, especially the presence of osteophytes, in former elite athletes than controls. The risk of OA was higher with participation in mixed sports, especially soccer or power sports, than endurance sport. However, the prevalence of clinical OA between former elite athletes and controls was similar, with less hip/knee disability in former athletes. Moderate daily recreational or sport activities, whatever the type of sport, are not a consistent risk factor for clinical or radiographic knee/hip OA. Risk of injury in different sports may be the key factor to understanding the risk of OA related to sport. PMID:27103057

  2. Influencing factors analysis of spontaneous knee joint osteoarthritis among middle aged and old aged pople in Xi'an

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; WANG Kun-zheng; DANG Xiao-qian; BAI Chuan-yi; WANG Chun-sheng; SHI ZHi-bin; MA Shu-qiang

    2007-01-01

    Objective:To explore the prevalence rate of knee joint osteoarthritis and its pathogenetic features among the middle-aged and old aged people in the urban and rural area of Xi'an. Methods: From May to October 2005, 1 538 Han nationality above 40 years in Xi'an were investigated according to stratified and cluster random sampling. The same questionnaire was delivered to subjects who had been given normotopia and lateral position radiographic examination in both knees. Excluded from etiological arthritis, some subjects with clinical symptoms and a radiographic grade (beyond Kellgren & Lawrence grade Ⅱ ) were finally diagnosed as spontaneous knee joint osteoarthritis. All analyses were performed with SPSS 13.0 and t test, U test. Single factor analysis and multiple logistic regression analysis were used to analyze dates. Results: The total prevalence of spontaneous knee joint osteoarthritis was 12. 1% with 2.5% and 2.1% for right and left knees, respectively. The prevalence of knee joint osteoarthritis in women was 2.5 times of that in men (17.2% vs 6.8%, P=0.000). the osteophyte prevalence in women was 2.3 times of that in men (26.5% vs 11.4%, P=0.000). The prevalence of knee joint osteoarthritis and osteophyte increased with the growth of age. So did the symptomatic knee, except for the age group of 56-60 years and 66-70 years. The prevalence of symptomatic knee joint for urban area was significantly higher than that for rural area (56. 3% vs 45.3%, P=0.003). In women, the prevalence of knee joint osteoarthritis increased significantly with the increasing of body mass index, which had not been observed in men. Female and obesity are the risk factors for osteoarthritis, but bean and its products and meat could prevent the osteoarthritis. Conclusion: Old age, female and obesity serve as risk factors for knee joint osteoarthritis.

  3. Concreteness and Psychological Distance in Natural Language Use.

    Science.gov (United States)

    Snefjella, Bryor; Kuperman, Victor

    2015-09-01

    Existing evidence shows that more abstract mental representations are formed and more abstract language is used to characterize phenomena that are more distant from the self. Yet the precise form of the functional relationship between distance and linguistic abstractness is unknown. In four studies, we tested whether more abstract language is used in textual references to more geographically distant cities (Study 1), time points further into the past or future (Study 2), references to more socially distant people (Study 3), and references to a specific topic (Study 4). Using millions of linguistic productions from thousands of social-media users, we determined that linguistic concreteness is a curvilinear function of the logarithm of distance, and we discuss psychological underpinnings of the mathematical properties of this relationship. We also demonstrated that gradient curvilinear effects of geographic and temporal distance on concreteness are nearly identical, which suggests uniformity in representation of abstractness along multiple dimensions.

  4. Efficient analysis of dielectric radomes using multilevel fast multipole algorithm with CRWG basis

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A full-wave analysis of the electromagnetic problem of a three-dimensional (3-D) antenna radiating through a 3-D dielectric radome is preserued.The problem is formulated using the Poggio-Miller-Chang-Harrington-Wu(PMCHW) approach for homogeneous dielectric objects and the electric field integral equation for conducting objects.The integral equations are discretized by the method of moment (MoM),in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions.The resultant matrix equation is then solved by the multilevel fast multipole algorithm (MLFMA) and fast far-field approximation (FAFFA) is used to further accelerate the computation.The radiation patterns of dipole arrays in the presence of radomes are presented.The numerical results demonstrate the accuracy and versatility of this method.

  5. Impact of contour on aesthetic judgments and approach-avoidance decisions in architecture

    DEFF Research Database (Denmark)

    Vartanian, Oshin; Navarrete, Gorka; Chatterjee, Anjan;

    2013-01-01

    On average, we urban dwellers spend about 90% of our time indoors, and share the intuition that the physical features of the places we live and work in influence how we feel and act. However, there is surprisingly little research on how architecture impacts behavior, much less on how it influences......, participants were more likely to judge spaces as beautiful if they were curvilinear than rectilinear. Neuroanatomically, when contemplating beauty, curvilinear contour activated the anterior cingulate cortex exclusively, a region strongly responsive to the reward properties and emotional salience of objects....... Complementing this finding, pleasantness—the valence dimension of the affect circumplex—accounted for nearly 60% of the variance in beauty ratings. Furthermore, activation in a distributed brain network known to underlie the aesthetic evaluation of different types of visual stimuli covaried with beauty ratings...

  6. Concreteness and Psychological Distance in Natural Language Use.

    Science.gov (United States)

    Snefjella, Bryor; Kuperman, Victor

    2015-09-01

    Existing evidence shows that more abstract mental representations are formed and more abstract language is used to characterize phenomena that are more distant from the self. Yet the precise form of the functional relationship between distance and linguistic abstractness is unknown. In four studies, we tested whether more abstract language is used in textual references to more geographically distant cities (Study 1), time points further into the past or future (Study 2), references to more socially distant people (Study 3), and references to a specific topic (Study 4). Using millions of linguistic productions from thousands of social-media users, we determined that linguistic concreteness is a curvilinear function of the logarithm of distance, and we discuss psychological underpinnings of the mathematical properties of this relationship. We also demonstrated that gradient curvilinear effects of geographic and temporal distance on concreteness are nearly identical, which suggests uniformity in representation of abstractness along multiple dimensions. PMID:26239108

  7. Political conservatism, rigidity, and dogmatism in American foreign policy officials: the 1966 Mennis data.

    Science.gov (United States)

    Kemmelmeier, Markus

    2007-01-01

    Researchers have established a relationship between political orientation and cognitive styles (A. Chirumbolo, 2002; J. T. Jost, J. Glaser, A. W. Kruglanski, & F. Sulloway, 2003a, 2003b; M. Kemmelmeier, 1997). In this article, the author examined whether this finding is true in the political elite, whether the relationship is linear or curvilinear, and whether interest in politics moderates the relationship between political orientation and cognitive styles. He used a 1966 sample of American foreign policy officials (N = 95) to examine the relationship between self-described conservatism and party identification and individual differences in rigidity and dogmatism. Rigidity was related to self-described conservatism, but this relationship was only significant among participants high in political interest, whereas dogmatism was unconditionally related to party identification. All relationships were linear and did not contain a curvilinear component. PMID:17312688

  8. SIMULATION OF STRONG TURBULENCE FLOW WITH FREE SURFACE INCLUDING THE EFFECTS OF STREAMLINE CURVATURE

    Institute of Scientific and Technical Information of China (English)

    DAI Hui-chao; LIU Yu-ling; WEI Wen-li

    2005-01-01

    This paper is concerned with a mathematical model for two-dimensional strong turbulence flow with free surface including the effects of streamline curvature in orthogonal curvilinear coordinate system, with which the characteristics of the turbulence flow field on the ogee spillway was numerical simulated. In the numerical simulation, the flow control equations in orthogonal curvilinear coordinate system were discretized by the finite volume method, the physical parameters( P, U,V,K,ε,γt,etc.) were arranged on a staggered grid, the discretized equations were solved with the SIMPLEC method, and the complex free surface was dealt with VOF method. The computed results show that the velocity fields, pressure field, shear stress distribution and kinetic energy of turbulent flow on the ogee spillway are in agreement with experimental data. This confirms that the model can be used for numerical simulation of the turbulence flow on ogee spillway.

  9. Moving grids for magnetic reconnection via Newton-Krylov methods

    KAUST Repository

    Yuan, Xuefei

    2011-01-01

    This paper presents a set of computationally efficient, adaptive grids for magnetic reconnection phenomenon where the current density can develop large gradients in the reconnection region. Four-field extended MagnetoHydroDynamics (MHD) equations with hyperviscosity terms are transformed so that the curvilinear coordinates replace the Cartesian coordinates as the independent variables, and moving grids\\' velocities are also considered in this transformed system as a part of interpolating the physical solutions from the old grid to the new grid as time advances. The curvilinear coordinates derived from the current density through the Monge-Kantorovich (MK) optimization approach help to reduce the resolution requirements during the computation. © 2010 Elsevier B.V. All rights reserved.

  10. The Takete-Maluma phenomenon in autism spectrum disorders.

    Science.gov (United States)

    Occelli, Valeria; Esposito, Gianluca; Venuti, Paola; Arduino, Giuseppe Maurizio; Zampini, Massimiliano

    2013-01-01

    It has been reported that people tend to preferentially associate phonemes like /m/, /l/, /n/ to curvilinear shapes and phonemes like /t/, /z/, /r/, /k/ to rectilinear shapes. Here we evaluated the performance of children/adolescents with autism spectrum disorders (ASD) and neurotypical controls in this audiovisual congruency phenomenon. Pairs of visual patterns (curvilinear vs rectilinear) were presented to a group of ASD participants (low- or high-functioning) and a group of age-matched neurotypical controls. Participants were asked to associate each item to non-meaningful phoneme clusters. ASD participants showed a lower proportion of expected association responses than the controls. Within the ASD group the performance varied as a function of the severity of the symptomatology. These data suggest that children/adolescents with ASD show, although at different degrees as a function of the severity of the ASD, lower phonetic-iconic congruency response patterns than neurotypical controls, pointing to poorer multisensory integration capabilities. PMID:23700961

  11. Job stress and job performance controversy: an empirical assessment.

    Science.gov (United States)

    Jamal, M

    1984-02-01

    This study examined the relationship between job stress and employees' performance and withdrawal behavior among nurses (N = 440) in two hospitals in a metropolitan Canadian city on the east coast. Job stressors assessed included role ambiguity, role overload, role conflict, and resource inadequacy. Employees' performance was operationalized in terms of job performance, motivation, and patient care skill. Withdrawal behaviors assessed were absenteeism, tardiness, and anticipated turnover. Multiple regressions, curvilinear correlation coefficients, and canonical correlations were computed to test the nature of the relationship between stressors and the criterion variables of the study. In general, data were more supportive of the negative linear relationship between stress and performance than for positive linear or curvilinear relationship. However, the stressor role ambiguity did exhibit a monotonic nonlinear relationship with a number of criterion variables. Employees' professional and organizational commitment were proposed to moderate the stress-performance relationship. However, the data only partially supported the role of the moderators. PMID:10265480

  12. Widespread Occurrence of Trenching Patterns in the Granulation Field: Evidence for Roll Convection?

    CERN Document Server

    Getling, A V

    2007-01-01

    Time-averaged series of granulation images are analysed using COLIBRI, a purpose-adapted version of a code originally developed to detect straight or curvilinear features in aerospace images. The algorithm of image processing utilises a nonparametric statistical criterion that identifies a straight-line segment as a linear feature (lineament) if the photospheric brightness at a certain distance from this line is on both sides stochastically lower or higher than at the line itself. Curvilinear features can be detected as chains of lineaments, using a criterion modified in some way. Once the input parameters used by the algorithm are properly adjusted, the algorithm highlights ``ridges'' and ``trenches'' in the relief of the brightness field, drawing white and dark lanes. The most remarkable property of the trenching patterns is a nearly-universally-present parallelism of ridges and trenches. Since the material upflows are brighter than the downflows, the alternating parallel light and dark lanes should reflect...

  13. Complex geometrical optics of inhomogeneous and nonlinear saturable media

    Science.gov (United States)

    Berczynski, Pawel

    2013-05-01

    The method of complex geometrical optics (CGO) is presented, which describes Gaussian beam (GB) diffraction and self-focusing along curvilinear trajectory in smoothly inhomogeneous and nonlinear saturable media. CGO method reduces the problem of Gaussian beam propagation in inhomogeneous and nonlinear media to the system of the first order ordinary differential equations for the complex curvature of the wave front and for GB amplitude, which can be readily solved both analytically and numerically. As a result, CGO radically simplifies the description of Gaussian beam diffraction and self-focusing effects as compared to the other methods of nonlinear optics such as: variational method approach, method of moments and beam propagation method. The power of CGO method is presented on the example of the evolution of beam intensity and wave front cross-section along curvilinear central ray with torsion in weakly absorptive and nonlinear saturable graded-index fiber, where the effect of initial beam ellipticity is included into our description.

  14. Erosion below submarine structures

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, S.; Asp Hansen, E.

    1997-07-01

    A numerical model for the development of bed dominated scour around sub-sea structures is presented. The hydrodynamic part of the model is based on a modified potential flow theory. The purpose of the present study has been to develop relatively simple models, yet complex enough to capture the main physics that can be used as engineering tools. An overview of scour phenomena and the basic problems of scour in steady current flow is presented. A hydrodynamic model for horseshoe vortex is presented, as well as a model for the bed transport, and examples are given. The scour in oscillatory flow and a curvilinear model for suspended sediment calculations are described. An advection-diffusion model (formulated in a curvilinear stretched coordinate system) has been developed and is described in an article which has been submitted for publication, a copy of the article is enclosed in Appendix E of the report. (EG)

  15. Dissolvable films of silk fibroin for ultrathin conformal bio-integrated electronics.

    Science.gov (United States)

    Kim, Dae-Hyeong; Viventi, Jonathan; Amsden, Jason J; Xiao, Jianliang; Vigeland, Leif; Kim, Yun-Soung; Blanco, Justin A; Panilaitis, Bruce; Frechette, Eric S; Contreras, Diego; Kaplan, David L; Omenetto, Fiorenzo G; Huang, Yonggang; Hwang, Keh-Chih; Zakin, Mitchell R; Litt, Brian; Rogers, John A

    2010-06-01

    Electronics that are capable of intimate, non-invasive integration with the soft, curvilinear surfaces of biological tissues offer important opportunities for diagnosing and treating disease and for improving brain/machine interfaces. This article describes a material strategy for a type of bio-interfaced system that relies on ultrathin electronics supported by bioresorbable substrates of silk fibroin. Mounting such devices on tissue and then allowing the silk to dissolve and resorb initiates a spontaneous, conformal wrapping process driven by capillary forces at the biotic/abiotic interface. Specialized mesh designs and ultrathin forms for the electronics ensure minimal stresses on the tissue and highly conformal coverage, even for complex curvilinear surfaces, as confirmed by experimental and theoretical studies. In vivo, neural mapping experiments on feline animal models illustrate one mode of use for this class of technology. These concepts provide new capabilities for implantable and surgical devices.

  16. Near-Body Grid Adaption for Overset Grids

    Science.gov (United States)

    Buning, Pieter G.; Pulliam, Thomas H.

    2016-01-01

    A solution adaption capability for curvilinear near-body grids has been implemented in the OVERFLOW overset grid computational fluid dynamics code. The approach follows closely that used for the Cartesian off-body grids, but inserts refined grids in the computational space of original near-body grids. Refined curvilinear grids are generated using parametric cubic interpolation, with one-sided biasing based on curvature and stretching ratio of the original grid. Sensor functions, grid marking, and solution interpolation tasks are implemented in the same fashion as for off-body grids. A goal-oriented procedure, based on largest error first, is included for controlling growth rate and maximum size of the adapted grid system. The adaption process is almost entirely parallelized using MPI, resulting in a capability suitable for viscous, moving body simulations. Two- and three-dimensional examples are presented.

  17. A naturalistic study of the word frequency effect in episodic recognition.

    Science.gov (United States)

    Chalmers, K A; Humphreys, M S; Dennis, S

    1997-11-01

    In order to separate the effects of experience from other characteristics of word frequency (e.g., orthographic distinctiveness), computer science and psychology students rated their experience with computer science technical items and nontechnical items from a wide range of word frequencies prior to being tested for recognition memory of the rated items. For nontechnical items, there was a curvilinear relationship between recognition accuracy and word frequency for both groups of students. The usual superiority of low-frequency words was demonstrated and high-frequency words were recognized least well. For technical items, a similar curvilinear relationship was evident for the psychology students, but for the computer science students, recognition accuracy was inversely related to word frequency. The ratings data showed that subjective experience rather than background word frequency was the better predictor of recognition accuracy. PMID:9421563

  18. Decelerating the diminishing returns of citizenship on task performance: the role of social context and interpersonal skill.

    Science.gov (United States)

    Ellington, J Kemp; Dierdorff, Erich C; Rubin, Robert S

    2014-07-01

    Recent scholarship on citizenship behavior demonstrates that engaging too often in these behaviors comes at the expense of task performance. In order to examine the boundary conditions of this relationship, we used resource allocation and social exchange theories to build predictions regarding moderators of the curvilinear association between citizenship and task performance. We conducted a field study of 366 employees, in which we examined the relationship between the frequency of interpersonal helping behavior and task performance and tested for the moderating influences of 3 social context features (social density, interdependence, and social support) and of employees' levels of interpersonal skill. Results provided corroborating evidence of the diminishing returns between citizenship and task performance. Further, these diminishing returns were decelerated when contexts were characterized by high interdependence and social density and when employees possessed strong interpersonal skills. Implications for extending future citizenship theory and research to incorporate curvilinearity are presented.

  19. Differentiating Pneumothorax from the Common Radiographic Skinfold Artifact.

    Science.gov (United States)

    Kattea, M Obadah; Lababede, Omar

    2015-06-01

    Pneumothorax can be a critical medical condition. The radiographic curvilinear appearance of pneumothorax can be mimicked by a skinfold artifact. Radiographic differentiation of the two entities is achieved in most cases by careful analysis of the characteristics of the linear shadow and its course. A thin, sharply defined opaque density representing the visceral pleura is the hallmark of pneumothorax. The added density of a skinfold presents as a broad opacity, which is outlined laterally by a sharply defined lucent line as a result of the Mach band effect and adjacent air. Unlike pneumothorax, a skinfold produces a line that does not follow the expected course of visceral pleura. Additional features, such as the absence of increased lucency laterally and the projection of lung markings across the curvilinear shadow, can help in the correct identification of skinfolds. Repeating the chest radiograph or using other imaging modalities can be considered in difficult cases.

  20. Aeroelastic Tailoring via Tow Steered Composites

    Science.gov (United States)

    Stanford, Bret K.; Jutte, Christine V.

    2014-01-01

    The use of tow steered composites, where fibers follow prescribed curvilinear paths within a laminate, can improve upon existing capabilities related to aeroelastic tailoring of wing structures, though this tailoring method has received relatively little attention in the literature. This paper demonstrates the technique for both a simple cantilevered plate in low-speed flow, as well as the wing box of a full-scale high aspect ratio transport configuration. Static aeroelastic stresses and dynamic flutter boundaries are obtained for both cases. The impact of various tailoring choices upon the aeroelastic performance is quantified: curvilinear fiber steering versus straight fiber steering, certifiable versus noncertifiable stacking sequences, a single uniform laminate per wing skin versus multiple laminates, and identical upper and lower wing skins structures versus individual tailoring.

  1. The Money Buffer Effect in China: A Higher Income Cannot Make You Much Happier but Might Allow You to Worry Less.

    Science.gov (United States)

    Li, Bin; Li, Aimei; Wang, Xiaotian; Hou, Yunsong

    2016-01-01

    This study examined the possibility that there is a curvilinear relationship between income and subjective well-being in China. This study also investigated whether this curvilinear relationship is moderated by social class and mediated by respondents' material affluence. The study was conducted in China, and the sample consisted of 900 blue-collar workers and 546 white-collar workers. The results for emotional well-being showed that income significantly predicted negative affect but not positive affect. This finding indicates that in China, high incomes may not make people happier but might allow them to worry less, which we call the "money buffer effect." The results also showed that material affluence mediates the interaction effect between income and social class on subjective well-being. The implications of these results for future research and practice are discussed.

  2. Efficient Computation of N-S Equation with Free Surface Flow Around an ACV on ShirazUCFD Grid

    Science.gov (United States)

    Sheikhalishahi, Seyyed Mehdi; Alizadehrad, Davood; Dastghaibyfard, Gholamhossein; Alishahi, Mohammad Mehdi; Nikseresht, Amir Hossein

    This paper presents the application of a parallel high accuracy simulation code for Incompressible Navier-Stokes solution with free surface flow around an ACV (Air Cushion Vehicle) on ShirazUCFD Grid environment. The parallel finite volume code is developed for incompressible Navier-Stokes solver on general curvilinear coordinates system for modeling free surface flows. A single set of dimensionless equations is derived to handle both liquid and air phases in viscous incompressible free surface flow in general curvilinear coordinates. The volume of fluid (VOF) method with lagrangian propagation in computational domain for modeling the free surface flow is implemented. The parallelization approach uses a domain decomposition method for the subdivision of the numerical grid, the SPMD program model and MPICH-G2 as the message passing environment is used to obtain a portable application.

  3. A correlation analysis of the relationship between X-ray manifestation and knee pain degree in knee osteoarthritis%膝骨关节炎X线表现与膝关节疼痛程度的相关性分析

    Institute of Scientific and Technical Information of China (English)

    冯欢欢; 王培民; 范竞; 程建

    2013-01-01

    目的:分析膝骨关节炎X线表现与膝关节疼痛程度的相关性.方法:为103例膝骨关节炎患者拍摄正位和侧位膝关节数字透视摄影片,测定膝关节内侧间距、外侧间距、内外侧间距比值,并对膝关节骨赘进行评分.同时采用视觉模拟评分法评定膝关节疼痛程度.对膝关节X线表现与膝关节疼痛评分进行相关性分析.结果:本组患者膝关节疼痛评分为(7.49±1.23)分;膝关节内侧间距(38.02±9.53) mm,外侧间距(48.01±10.59) mm,内外侧间距比值(1.33±0.37)%;膝关节骨赘评分,外侧区(0.33±0.47)分,中间区(0.81±0.40)分,内侧区(0.34±0.48)分,髌股区(0.75±0.44)分,总分(2.22±1.21)分;无骨赘者9例,1个部位出现骨赘者20例,2个部位出现骨赘者32例,3个部位出现骨赘者23例,4个部位出现骨赘者19例.相关性分析结果显示,膝关节中间区骨赘评分和髌股区骨赘评分与膝关节疼痛评分呈正相关(r =0.203,P=0.014;r=0.177,P=0.032).结论:膝骨关节炎患者的膝关节中间区和髌股区骨赘是影响膝关节疼痛程度的主要解剖因素.%Objective:To analyse the correlation between X-ray manifestation and knee pain degree in knee osteoarthritis (KOA).Methods:The frontal and lateral digital radiograph of knee joints of 103 patients with KOA were used to assess such parameters as the medial joint space width,lateral joint space width and the ratio of medial joint space width to lateral joint space width,and the knee joint osteophytes were measured and scored.Meanwhile,the degree of knee joint pain were measured by using a visual analogue scale.Then,the relationship between X-ray manifestation and knee joint pain score were analysed by correlation analysis.Results:The knee joint pain scores of the patients were (7.49 ± 1.23).The medial joint space width,lateral joint space width and the ratio of medial joint space width to lateral joint space width were (38.02 ± 9.53) mm,(48.01 ± 10.59) mm,(1

  4. EBF3GLWingOpt: A Framework for Multidisciplinary Design Optimization of Wings Using SpaRibs

    OpenAIRE

    Liu, Qiang

    2014-01-01

    A global/local framework for multidisciplinary optimization of generalized aircraft wing structure has been developed. The concept of curvilinear stiffening members (spars, ribs and stiffeners) has been applied in the optimization of a wing structure. A global wing optimization framework EBF3WingOpt, which integrates the static aeroelastic, flutter and buckling analysis, has been implemented for exploiting the optimal design at the wing level. The wing internal structure is optimized using cu...

  5. Aloe vera na criopreservação do sêmen de tambaqui (Colossoma macropomum)

    OpenAIRE

    M.A.P. Melo-Maciel; L.V. Leite-Castro; J.S. Leite; M.S. Oliveira; P.S. Almeida-Monteiro; J. F. Nunes; C.S.B. Salmito-Vanderley

    2015-01-01

    This study aimed to evaluate the extract of Aloe vera (AV) associated or not with 10% Dimethylsulfoxide (DMSO) in cryopreservation of tambaqui semen. For the formation of the pools (n= 14), 30 males were hormonally induced twice. Each pool had the objective motility, curvilinear velocity, straight-line velocity, average path velocity and morphology analyzed before and after cryopreservation of semen. The means for cryopreservation were constituted of Powder Coconut Water-104 diluent added DMS...

  6. The Relationship Between the Quantity of Alcohol Consumed and the Severity of Sexual Assaults Committed by College Men

    OpenAIRE

    Abbey, Antonia; Clinton-Sherrod, A. Monique; McAuslan, Pam; Zawacki, Tina; Buck, Philip O

    2003-01-01

    Researchers have suggested that intoxicated perpetrators may act more violently than other perpetrators, although empirical findings have been mixed. Past research has focused on whether or not alcohol was consumed, rather than the quantity consumed, and this may explain these inconsistent findings. The authors hypothesized that the quantity of alcohol consumed would have a curvilinear relationship to the severity of the assault. Data were collected from 113 college men who reported that they...

  7. Nomography

    CERN Document Server

    Otto, Edward

    1963-01-01

    Nomography deals with geometrical transformations, particularly projective transformations of a plane. The book reviews projective plane and collineation transformations in geometrical and algebraical terms. The geometrical approach aims at permitting the use of elementary geometrical methods in drawing collineation nomograms consisting of three rectilinear scales. The algebraical treatment concerns nomograms containing curvilinear scales. The text explains functional scales that include the graph of a function and a logarithmic scale. The book explores equations which can be represented by el

  8. The relationship between signal quality and physical condition: is sexual signalling honest in the three-spined stickleback?

    OpenAIRE

    Candolin, Ulrika

    1999-01-01

    Honest sexual signalling requires that the level of advertisement reveals mate quality. In the three-spined stickleback, Gasterosteus aculeatus, females base their mate choice mainly on the intensity of the males’ red breeding coloration. Different results have, however, been obtained on the relationship between red breeding coloration and physical condition. In this study, the relationship was curvilinear in a natural population, with males in good and poor condition (measured ...

  9. THE CONTINUOUS SCHWARTZ-CHRISTOFFEL TRANSFORMS CSCT

    OpenAIRE

    Rechea Alberola, Manuel; Basset Salom, Luisa

    1996-01-01

    This paper shows a method, developped by the authors, to transform series of curvilinear segments, which intersect at angles of non zero magnitude, into real axis, as a complex function transform.The method initiates from the Schwarz-Christofel transformation an generalizes it.. Examples of how to carry out the computations are shown and some new results are presented Rechea Alberola, M.; Basset Salom, L. (1996). THE CONTINUOUS SCHWARTZ-CHRISTOFFEL TRANSFORMS CSCT. III Congreso de Métodos ...

  10. Algorithm development for Maxwell's equations for computational electromagnetism

    Science.gov (United States)

    Goorjian, Peter M.

    1990-01-01

    A new algorithm has been developed for solving Maxwell's equations for the electromagnetic field. It solves the equations in the time domain with central, finite differences. The time advancement is performed implicitly, using an alternating direction implicit procedure. The space discretization is performed with finite volumes, using curvilinear coordinates with electromagnetic components along those directions. Sample calculations are presented of scattering from a metal pin, a square and a circle to demonstrate the capabilities of the new algorithm.

  11. The relation between conscientiousness, empowerment and performance

    Directory of Open Access Journals (Sweden)

    Riëtte Sutherland

    2007-02-01

    Full Text Available This study examined the relationship between conscientiousness, empowerment and job performance among information technology professionals. An Employee Empowerment Questionnaire (EEQ, a Conscientiousness Scale and a Social Desirability Scale were administered to 101 information technology customer service engineers. Managers completed a Performance Evaluation Questionnaire (PEQ for each customer service engineer. The results indicated a significant relationship between conscientiousness and empowerment. A curvilinear relationship was found between empowerment and performance. The practical and theoretical implications of the findings are discussed.

  12. Anterior capsule tear after laser iridotomy complicating phacoemulsification

    OpenAIRE

    Vivien Cherng Hui, Yip; Sanjay, Srinivasan; Benjamin Chong-Ming, Chang

    2011-01-01

    A 70-year-old Indian lady had a history of bilateral laser peripheral iridotomy (LPI) for primary angle closure. Subsequently she developed cataract in both the eyes. Right eye cataract surgery was complicated by an anterior capsule rupture, which was discovered intra-operatively at the site of the LPI. Trypan blue was used to stain the anterior capsule to delineate the anterior capsule defect. An attempt at continuous curvilinear capsulorhexis was unsuccessful, and the anterior capsulotomy w...

  13. Transcorneal three-port vitrectomy without conjunctival incision.

    OpenAIRE

    Matsumoto, Makiko; Suzuma, Kiyoshi; Miyamura, Noritake; Tsuiki, Eiko; Kitaoka, Takashi

    2011-01-01

    Background: Although widely accepted, pars plana vitrectomy is difficult to perform when patients have a large filtering bleb. We describe technical details of 25-gauge transcorneal vitrectomy and the clinical outcomes. Methods: We performed 25-gauge transcorneal vitrectomy on seven eyes of seven patients (female: male, 4:3; age, 39 to 77 years; mean, 66.1 years) between January 2005 and February 2007. Phacoemulsification via a corneal incision was followed by continuous curvilinear capsulorr...

  14. Successful Removal of Large Intraocular Foreign Body by 25-Gauge Microincision Vitrectomy Surgery

    OpenAIRE

    Hiroshi Kunikata; Megumi Uematsu; Toru Nakazawa; Nobuo Fuse

    2011-01-01

    We describe a new technique for removing a large intraocular foreign body by 25-gauge microincision vitrectomy surgery (25G-MIVS). Noncomparative interventional case series were performed at a single centre. Two patients with a long smooth intraocular vitreal foreign body underwent phacoemulsification and aspiration, intraocular lens implantation, 25G-MIVS, and extraction of the foreign body. The foreign body was removed through a posterior capsulorhexis, anterior continuous curvilinear capsu...

  15. Temperature, Cultural Masculinity, and Domestic Political Violence. A Cross-National Study

    OpenAIRE

    van de Vliert, E.; Schwartz, S.H.; Huismans, S.E.; Hofstede, G.; Daan, S

    1999-01-01

    Cross-national data sets were used to examine the association between ambient temperature and internal political violence in 136 countries between 1948 and 1977. Political riots and armed attacks occur more frequently in warm countries than in both cold and hot countries, after controlling for effects of population size and density and levels of socioeconomic development and democracy. National differences on the cultural masculinity dimension, however, do account for this curvilinear tempera...

  16. The impact of fuel ownership on intrastate violence

    OpenAIRE

    Wegenast, Tim

    2013-01-01

    The impact of natural resources on intrastate violence has been increasingly analyzed in the peace and conflict literature. Surprisingly, little quantitative evidence has been gathered on the effects of the resource-ownership structure on internal violence. This paper uses a novel dataset on oil and natural gas property rights covering 40 countries during the period 1989–2010. The results of regression analyses employing logit models reveal that the curvilinear effect between hydrocarbon prod...

  17. Doubly Periodic Cracks in the Anisotropic Medium with the Account of Contact of Their Faces

    Directory of Open Access Journals (Sweden)

    Maksymovych Olesya

    2014-09-01

    Full Text Available The paper presents complex variable integral formulae and singular boundary integral equations for doubly periodic cracks in anisotropic elastic medium. It utilizes the numerical solution procedure, which accounts for the contact of crack faces and produce accurate results for SIF evaluation. It is shown that the account of contact effects significantly influence the SIF of doubly periodic curvilinear cracks both for isotropic and anisotropic materials.

  18. GENERATIONAL DIFFERENCES IN COHABITATION AND MARRIAGE IN THE U.S.*

    OpenAIRE

    Brown, Susan L.; Van Hook, Jennifer; Glick, Jennifer E.

    2008-01-01

    We use data from pooled 2000–2004 Current Population Surveys to examine generational differences in cohabitation and marriage among men and women ages 20–34 in the U.S. Consistent with our expectation and in line with assimilation theory, levels of cohabitation rise across succeeding generations. In contrast, generational differences in marriage follow a curvilinear pattern such that those in the second generation are least likely to be married, which supports some contemporary extensions of ...

  19. Coherent electron transport in a helical nanotube

    OpenAIRE

    Liang, Guo-Hua; Wang, Yong-long(Department of Physics, Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing University, 210093, Nanjing, China); Du, Long; Jiang, Hua; Kang, Guang-Zhen; Zong, Hong-shi(Department of Physics, Nanjing University, Nanjing 210093, China)

    2016-01-01

    The quantum dynamics of carriers bound to helical tube surfaces is investigated in a thin-layer quantization scheme. By numerically solving the open-boundary Schr$\\ddot{\\rm o}$dinger equation in curvilinear coordinates, geometric effect on the coherent transmission spectra is analysed in the case of single propagating mode as well as multimode. It is shown that, the coiling endows the helical nanotube with different transport properties from a bent cylindrical surface. Fano resonance appears ...

  20. Weight changes in wild Wolves, Canis lupus, from ages 2 to 24 months

    Science.gov (United States)

    David, Mech L.

    2008-01-01

    Weights of 118 female and 141 male Minnesota Wolves (Canis lupus) aged 2-24 months increased almost linearly from about 8 kg for females and 10 kg for males at 3 months to 30 kg for females and 32 kg for males at 10-12 months and then tended to increase much more slowly in an overall curvilinear trend. Considerable variation was apparent for both sexes during their first year.

  1. Numerical calculation of the internal flow field in a centrifugal compressor impeller

    Science.gov (United States)

    Walitt, L.; Harp, J. L., Jr.; Liu, C. Y.

    1975-01-01

    An iterative numerical method has been developed for the calculation of steady, three-dimensional, viscous, compressible flow fields in centrifugal compressor impellers. The computer code, which embodies the method, solves the steady three dimensional, compressible Navier-Stokes equations in rotating, curvilinear coordinates. The solution takes place on blade-to-blade surfaces of revolution which move from the hub to the shroud during each iteration.

  2. Mathematical Methods for Optical Physics and Engineering

    Science.gov (United States)

    Gbur, Gregory J.

    2011-01-01

    1. Vector algebra; 2. Vector calculus; 3. Vector calculus in curvilinear coordinate systems; 4. Matrices and linear algebra; 5. Advanced matrix techniques and tensors; 6. Distributions; 7. Infinite series; 8. Fourier series; 9. Complex analysis; 10. Advanced complex analysis; 11. Fourier transforms; 12. Other integral transforms; 13. Discrete transforms; 14. Ordinary differential equations; 15. Partial differential equations; 16. Bessel functions; 17. Legendre functions and spherical harmonics; 18. Orthogonal functions; 19. Green's functions; 20. The calculus of variations; 21. Asymptotic techniques; Appendices; References; Index.

  3. The Role of Nonlinear Gradients in Parallel Imaging: A k-Space Based Analysis

    OpenAIRE

    Galiana, Gigi; Stockmann, Jason P.; TAM, LEO; Peters, Dana; Tagare, Hemant; Constable, R. Todd

    2012-01-01

    Sequences that encode the spatial information of an object using nonlinear gradient fields are a new frontier in MRI, with potential to provide lower peripheral nerve stimulation, windowed fields of view, tailored spatially-varying resolution, curved slices that mirror physiological geometry, and, most importantly, very fast parallel imaging with multichannel coils. The acceleration for multichannel images is generally explained by the fact that curvilinear gradient isocontours better complem...

  4. Application of Through-Flow Calculation to Design and Performance Prediction of Centrifugal Compressor

    OpenAIRE

    Choi, Y. S.; Kang, S.H.

    1999-01-01

    A computer code predicting the flows through the centrifugal compressor with the radial vaneless diffuser was developed and applied to investigate the detailed flowfields, i.e., secondary flows and jet-wake type flow pattern in design and off-design conditions. Various parameters such as slip factors, aerodynamic blockages, entropy generation and two-zone modeling which are widely used in design and performance prediction, were discussed.A control volume method based on a general curvilinear ...

  5. Patterns of visual attention to faces and objects in autism spectrum disorder

    OpenAIRE

    McPartland, James C.; Webb, Sara Jane; Keehn, Brandon; Dawson, Geraldine

    2011-01-01

    This study used eye-tracking to examine visual attention to faces and objects in adolescents with autism spectrum disorder (ASD) and typical peers. Point of gaze was recorded during passive viewing of images of human faces, inverted human faces, monkey faces, three-dimensional curvilinear objects, and two-dimensional geometric patterns. Individuals with ASD obtained lower scores on measures of face recognition and social-emotional functioning but exhibited similar patterns of visual attention...

  6. Numerical solution of free-boundary problems in fluid mechanics. Part 1. The finite-difference technique

    OpenAIRE

    Ryskin, G.; Leal, L. G.

    1984-01-01

    We present here a brief description of a numerical technique suitable for solving axisymmetric (or two-dimensional) free-boundary problems of fluid mechanics. The technique is based on a finite-difference solution of the equations of motion on an orthogonal curvilinear coordinate system, which is also constructed numerically and always adjusted so as to fit the current boundary shape. The overall solution is achieved via a global iterative process, with the condition of balance between total ...

  7. Parental Age Effects on Cortical Morphology in Offspring

    OpenAIRE

    Shaw, P.; Gilliam, M; Malek, M.; Rodriguez, N.; Greenstein, D.; Clasen, L.; Evans, A; Rapoport, J; Giedd, J.

    2012-01-01

    The age at which a parent has a child impacts the child's cognition and risk for mental illness. It appears that this risk is curvilinear, with both age extremes associated with lower intelligence and increased prevalence of some neuropsychiatric disorders. Little is known of the neural mechanisms underpinning this phenomenon. We extracted lobar volumes, surface areas, and cortical thickness from 489 neuroanatomic magnetic resonance images acquired on 171 youth. Using linear mixed model regre...

  8. Modeling shallow gravity-driven solid-fluid mixtures over arbitrary topography

    OpenAIRE

    Luca, Ioana; Tai, Yih-Chin; Kuo, Chih-Yu

    2009-01-01

    The purpose of this paper is to derive modeling equations for debris flows on real terrain. Thus, we use curvilinear coordinates adapted to the topography as introduced, e.g., by Bouchut and Westdickenberg, and develop depth-averaged models of gravity-driven saturated mixtures of solid grains and pore fluid on an arbitrary rigid basal surface. First, by only specifying the interaction force and ordering approximations in terms of an aspect ratio between a typical length perpendicu...

  9. Unusual Thymic Hyperplasia Mimicking Lipomatous Tumor in an Eight-Year-Old Boy with Concomitant Pericardial Lipomatosis and Right Facial Hemihypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoo Jin; Kim Woo Sun; Cheon, Jung Eun; Lim, Yun Jung; Kim, In One; Yeon, Kyung Mo [Seoul National University College of Medicine, Seoul (Korea, Republic of); Jung, Kyeong Cheon; Byun, Sun Ju [Seoul National University Hospital, Seoul (Korea, Republic of)

    2011-06-15

    We report a case of thymic hyperplasia accompanied by pericardial lipomatosis and right facial hemihypertrophy in an 8-year-old boy. On imaging studies, the hyperplastic thymus had prominent curvilinear and nodular fatty areas simulating a fat-containing anterior mediastinal mass, which is an unusual finding in children. To our knowledge, this is the first report on a child with a combination of thymic hyperplasia, pericardial lipomatosis, and right facial hemihypertrophy. The radiologic findings are presented with a brief discussion.

  10. The Study of Cutting Conditions Effects on the Damping Process Using the Experimental Taguchi Method

    OpenAIRE

    Haikel Mejri; Ziyed Sahraoui; Kamel Mehdi

    2016-01-01

    This article focuses on determining the effects of cutting conditions and their interactions on the cutting process damping in the case of curvilinear milling. The tests were performed using a numerical model simulation that allows the prediction of cutting forces and damping. The effects and interactions are determined using the Taguchi experimental method. Analysis of variance (ANOVA) was performed to know the level of importance of the machining parameters on the cutting damping process. T...

  11. Delaunay triangulation and computational fluid dynamics meshes

    Science.gov (United States)

    Posenau, Mary-Anne K.; Mount, David M.

    1992-01-01

    In aerospace computational fluid dynamics (CFD) calculations, the Delaunay triangulation of suitable quadrilateral meshes can lead to unsuitable triangulated meshes. Here, we present case studies which illustrate the limitations of using structured grid generation methods which produce points in a curvilinear coordinate system for subsequent triangulations for CFD applications. We discuss conditions under which meshes of quadrilateral elements may not produce a Delaunay triangulation suitable for CFD calculations, particularly with regard to high aspect ratio, skewed quadrilateral elements.

  12. THE STAKEHOLDERS ABILITY TO INFLUENCE THE RELATIONSHIP BETWEEN COMPANIES FINANCIAL PERFORMANCE (CFP) AND CORPORATE SOCIAL RESPONSIBILITY (CSR)

    OpenAIRE

    LILIANA NICOLETA SIMIONESCU

    2015-01-01

    Many scholars, academicians and practitioners have intensively examined corporate social responsibility (CSR) and corporate financial performance (CFP) in the literature on CSR along the years. Mainstream of these studies suggested a positive relationship or negative, neutral as few others found and/or curvilinear relationships. Hence, this paper develops an understanding for a mediator instrument as regards the relationship between corporate social responsibility and corporate financial perf...

  13. 乱流LESに適した一般座標系差分スキームについて

    OpenAIRE

    Kogaki, Tetsuya; Taniguchi, Nobuyuki; Matsuo, Yuichi; 小垣 哲也; 谷口 伸行; 松尾 裕一

    1999-01-01

    In order to conduct Direct Numerical Simulations (DNS) or Large Eddy Simulations (LES) of turbulent flow in complicated flow geometry, accurate finite difference methods are needed in generalized curvilinear coordinate system. Recently, it was shown that the analytical conservative properties of the set of basic equations are needed to be satisfied properly even in discrete basic equations in order to obtain accurate and stable solutions in simulations of incompressible turbulent flow using f...

  14. Perceived neighbourhood environmental attributes associated with adults׳ recreational walking

    DEFF Research Database (Denmark)

    Sugiyama, Takemi; Cerin, Ester; Owen, Neville;

    2014-01-01

    This study examined the strength and shape of associations between perceived environmental attributes and adults' recreational walking, using data collected from 13,745 adult participants in 12 countries. Perceived residential density, land use mix, street connectivity, aesthetics, safety from...... crime, and proximity to parks were linearly associated with recreational walking, while curvilinear associations were found for residential density, land use mix, and aesthetics. The observed associations were consistent across countries, except for aesthetics. Using data collected from environmentally...

  15. Materials for Multifunctional Balloon Catheters With Capabilities in Cardiac Electrophysiological Mapping and Ablation Therapy

    OpenAIRE

    Kim, Dae-Hyeong; Lu, Nanshu; Ghaffari, Roozbeh; Kim, Yun-Soung; Lee, Stephen P.; Xu, Lizhi; Wu, Jian; Kim, Rak-Hwan; Song, Jizhou; Liu, Zhuangjian; Viventi, Jonathan; de Graff, Bassel; Elolampi, Brian; Mansour, Moussa; Slepian, Marvin J.

    2011-01-01

    Development of advanced surgical tools for minimally invasive procedures represents an activity of central importance to improvements in human health. A key materials challenge is in the realization of bio-compatible interfaces between the classes of semiconductor and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on biocompatible materials and devices that integrate directly with the thin ela...

  16. Experimental and Numerical Evaluation of Thermal Performance of Steered Fibre Composite Laminates

    OpenAIRE

    Gürdal, Z.; Abdelal, G.; Wu, K. C.

    2011-01-01

    For Variable Stiffness (VS) composites with steered curvilinear tow paths, the fiber orientation angle varies continuously throughout the laminate, and is not required to be straight, parallel and uniform within each ply as in conventional composite laminates. Hence, the thermal properties (conduction), as well as the structural stiffness and strength, vary as functions of location in the laminate, and the associated composite structure is often called a “variable stiffness” composite structu...

  17. Magnetochiral symmetry breaking in a M\\"obius ring

    OpenAIRE

    Pylypovskyi, Oleksandr V.; Kravchuk, Volodymyr P.; Sheka, Denis D.; Makarov, Denys; Schmidt, Oliver G.; Gaididei, Yuri

    2014-01-01

    We show that the interaction of the magnetic subsystem of a curved magnet with the magnet curvature results in coupling of a topologically nontrivial magnetization pattern and topology of the object. The mechanism of this coupling is explored and illustrated by an example of ferromagnetic M\\"obius ring, where a topologically induced domain wall appears as a ground state in case of strong easy-normal anisotropy. For the M\\"obius geometry the curvilinear form of the exchange interaction produce...

  18. Temperature and Violent Crime in Dallas, Texas: Relationships and Implications of Climate Change

    OpenAIRE

    Gamble, Janet L.; Hess, Jeremy J.

    2012-01-01

    Introduction: To investigate relationships between ambient temperatures and violent crimes to determine whether those relationships are consistent across different crime categories and whether they are best described as increasing linear functions, or as curvilinear functions that decrease beyond some temperature threshold. A secondary objective was to consider the implications of the observed relationships for injuries and deaths from violent crimes in the context of a warming climate. To ad...

  19. Framework for the Buckling Optimization of Variable-Angle Tow Composite Plates

    OpenAIRE

    Wu, Zhangming; Raju, Gangadharan; Weaver, Paul M

    2015-01-01

    Variable-angle tow describes fibers in a composite lamina that have been steered curvilinearly. In doing so, substantially enlarged freedom for stiffness tailoring of composite laminates is enabled. Variable-angle tow composite structures have been shown to have improved buckling and postbuckling load-carrying capability when compared to straight fiber composites. However, their structural analysis and optimal design is more computationally expensive due to the exponential increase in number ...

  20. Progressive failure analysis of tow-placed, variable-stiffness composite panels

    OpenAIRE

    Lopes, CS; Camanho, PP; Guerdal, Z; Tatting, BF

    2007-01-01

    The past developments on tow-placement technology led to the production of machines capable of controlling fibre tows individually and placing them onto the surface of a laminate with curvilinear topology. Due to the variation of properties along their surface, such structures are termed variable-stiffness composite panels. In previous experimental research tow-steered panels have shown increased buckling load capacity as compared with traditional straight-fibre laminates. Also, numerical ana...

  1. Characteristic Ultrastructural Findings in Metablic and Storage Diseases

    OpenAIRE

    Ishihara, Tokuhiro; TAKAHASHI, MUTSUO; Gondo, Toshikazu; Kawano, Hiroo; Hoshii, Yoshinobu; Tamura, Suguru; Yamashita, Yoshimi; Yokota, Tadaaki; Kamei, Toshiaki; Koga, Mayumi; Uchino, Fumiya

    1994-01-01

    Electron microscopic observations performed with immunoelectron microscopy and specific cytochemical stainings play an important role in the diagnosis of diseases affectingcarbohydrate, lipid, protein, and mineral metabolism. The characteristic ultrastructural changes in affected cels of metabolic diseases are summarized as follows: (1) many glycogen granules in glycogenosis type Ⅰ; (2) many glycogen granules in glycogenosis type Ⅲ; (3) glycogenosomes in glycogenosis type Ⅱ; (4) curvilinear t...

  2. COMPUTER-AIDED DESIGN OF EMBOSSING TAPS

    OpenAIRE

    Lyczko, Kazimierz; Legutko, Stanislaw; Słonina, Lukasz; Sercer, Mladen

    2014-01-01

    The paper presents the development of an algorithm for computing the sizes of embossing taps. There are defined: the area of the software program encompassing the types and range of threads (metric and unified of the UNC, UNF, UNEF and G types), the design of the working portion (the conical and curvilinear shape of the forming portion, the number of lobes) and the overall dimensions and the profile type (incomplete or complete) of the thread to be formed. The general description and operatio...

  3. Rethinking the effects of stressors : a longitudinal study on personal initiative

    OpenAIRE

    Fay, Doris; Sonnentag, Sabine

    2002-01-01

    This study examined the relationship between stressors at work and personal initiative (PI), one proactive concept of extra-role performance. Using a control theory framework to describe the stress process, the authors hypothesized that stressors should be positively related to PI. This departs from findings of negative relationships between stressors and other types of performance. Furthermore, curvilinear relationships were tested. The analyses, based on 4 measurement waves of a longitudina...

  4. APPLICATIONS OF FRACTIONAL EXTERIOR DIFFERENTIAL IN THREE-DIMENSIONAL SPACE

    Institute of Scientific and Technical Information of China (English)

    陈勇; 闫振亚; 张鸿庆

    2003-01-01

    A brief survey of fractional calculus and fractional differential forms was firstly given. The fractional exterior transition to curvilinear coordinate at the origin were discussed and the two coordinate transformations for the fractional differentials for three-dimensional Cartesian coordinates to spherical and cylindrical coordinates are obtained, respectively. In particular, for v = m = 1 , the usual exterior transformations, between the spherical coordinate and Cartesian coordinate, as well as the cylindrical coordinate and Cartesian coordinate, are found respectively, from fractional exterior transformation.

  5. Planet-Disk Interaction revisited

    OpenAIRE

    Illenseer T. F.; Jung Manuel; Duschl W. J.

    2013-01-01

    We present results on our investigations of planet–disk interaction in protoplanetary disks. For the hydrodynamic simulations we use a second order semi–discrete total variation diminishing (TVD) scheme for systems of hyperbolic conservation laws on curvilinear grids. Our previously used method conserves the momentum in two dimensional systems with rotational symmetry. Additionally, we modified our simulation techniques for inertial angular momentum conservation even in two dimensional ...

  6. A framework to update Hofstede's cultural value indices: economic dynamics and institutional stability

    OpenAIRE

    Linghui Tang; PETER E KOVEOS

    2008-01-01

    This study offers an update of the Hofstede cultural value dimensions. We argue that changes in economic conditions are the source of cultural dynamics, while the endurance of institutional characteristics provides the foundation for cultural stability. It is found that national wealth, measured by GDP per capita, has a curvilinear relationship with individualism, long-term orientation, and power distance scores. Relatively speaking, uncertainty avoidance and masculinity mainly reflect some r...

  7. QL-09TRAJECTORY OF QUALITY OF LIFE AT END OF LIFE IN MALIGNANT GLIOMA: SUPPORT FOR THE TERMINAL DROP THEORY

    OpenAIRE

    Farace, Elana; Sheehan, Jonas

    2014-01-01

    Very little is known about quality of life (QOL) at end-of-life (EOL) in malignant brain tumor patients, which limits clinicians ability to best to help patients at this stage. The QOL trajectory at EOL has commonly been hypothesized to be "terminal decline," a linear relationship to time before death with a relatively gradual decline. Alternately, QOL at EOL could be hypothesized to be analogous to the "terminal drop" theory of cognitive aging, wherein the patient QOL has a curvilinear relat...

  8. Do they adapt or react? A comparison of the adaptation model and the stress reaction model among South African unemployed

    OpenAIRE

    Yannick Griep; Elfi Baillien; Wouter Vleugels; Sebastiaan Rothmann; Hans De Witte

    2014-01-01

    This study investigates affective experience as a function of unemployment duration in South Africa. The study contrasts two models. The stress reaction model proposes a linear decrease of affective experience as unemployment prolongs. The adaptation model assumes a curvilinear pattern between affective experience and unemployment duration. Analysis of variance (ANOVA) with contrast revealed no differences in affective experience between short-term (N = 101), long-term (N = 152) and very long...

  9. Exploratory data analysis with Matlab

    CERN Document Server

    Martinez, Wendy L; Solka, Jeffrey

    2010-01-01

    Since the publication of the bestselling first edition, many advances have been made in exploratory data analysis (EDA). Covering innovative approaches for dimensionality reduction, clustering, and visualization, Exploratory Data Analysis with MATLAB®, Second Edition uses numerous examples and applications to show how the methods are used in practice.New to the Second EditionDiscussions of nonnegative matrix factorization, linear discriminant analysis, curvilinear component analysis, independent component analysis, and smoothing splinesAn expanded set of methods for estimating the intrinsic di

  10. PROBE OF CONVOY LORRY’S ROADABILITY ON MODEL WITH FOUR FREEDOM DEGREES

    Directory of Open Access Journals (Sweden)

    M. Dyachuk

    2009-01-01

    Full Text Available The modeling of curvilinear movement of the lorry convoy is considered. The mathematical model of movement of two links flat system is developed; the software in the language of technical computing MATLAB is created; results of movement modeling on an example of jointed structure MAZ-643008 + NEFAZ-96931 taking into account distribution of steered wheels rotation angles and elastic properties of tires of wheels are analyzed.

  11. Analysis of Buried Dielectric Objects Using Higher-Order MoM for Volume Integral Equations

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav

    2004-01-01

    A higher-order method of moments (MoM) is applied to solve a volume integral equation for dielectric objects in layered media. In comparison to low-order methods, the higher-order MoM, which is based on higher-order hierarchical Legendre vector basis functions and curvilinear hexahedral elements......, requires considerably less number of unknowns and multilayer Green's function calculations for an accurate solution....

  12. Personality Plasticity After Age 30

    OpenAIRE

    Terracciano, Antonio; Costa, Paul T.; McCrae, Robert R.

    2006-01-01

    Rank-order consistency of personality traits increases from childhood to age 30. After that, different summaries of the literature predict a plateau at age 30, or at age 50, or a curvilinear peak in consistency at age 50. These predictions were evaluated at group and individual levels using longitudinal data from the Guilford-Zimmerman Temperament Survey and the Revised NEO Personality Inventory over periods of up to 42 years. Consistency declined toward a non-zero asymptote with increasing t...

  13. Study on artificial island port in Beibu gulf

    OpenAIRE

    Jinrong, A.M.; Yaqiong, B.G.; Kunqiang, C.L.; Zhimin, D.W.

    2013-01-01

    Regarding preservation and development of coast, artificial island port has been concerned for years by the government of Guangxi province which locates in the north coast of Beibu gulf in China. The nature conditions are suitable to build ports for the semi-closed gulf and curvilinear bays. There are three main port bays in Guangxi province named as Fangcheng, Qinzhou, and Tieshan. The former two bays have developed almost all the deepwater shoreline into docks. With many land reclamation pr...

  14. LIDAR DATA RESOLUTION VERSUS HYDRO-MORPHOLOGICAL MODELS FOR FLOOD RISK ASSESSMENT

    OpenAIRE

    A. Avanzi; Frank, E.; Righetto, M.; Fattorelli, S.

    2014-01-01

    Uncertainties in topographic data have a significant influence on hydro-morphological and hydraulic predictions and therefore on flood risk assessment. In this work, the effects of topographic data resolution on the results of hydro-morphologic and hydraulic simulations are analysed using respectively the morphological bi-dimensional curvilinear model MIKE 21C and mono-bidimensional SOBEK. The studies have been carried out in the Torre river, located in Northern Italy. The evaluations on hydr...

  15. Rashba Torque Driven Domain Wall Motion in Magnetic Helices.

    Science.gov (United States)

    Pylypovskyi, Oleksandr V; Sheka, Denis D; Kravchuk, Volodymyr P; Yershov, Kostiantyn V; Makarov, Denys; Gaididei, Yuri

    2016-01-01

    Manipulation of the domain wall propagation in magnetic wires is a key practical task for a number of devices including racetrack memory and magnetic logic. Recently, curvilinear effects emerged as an efficient mean to impact substantially the statics and dynamics of magnetic textures. Here, we demonstrate that the curvilinear form of the exchange interaction of a magnetic helix results in an effective anisotropy term and Dzyaloshinskii-Moriya interaction with a complete set of Lifshitz invariants for a one-dimensional system. In contrast to their planar counterparts, the geometrically induced modifications of the static magnetic texture of the domain walls in magnetic helices offer unconventional means to control the wall dynamics relying on spin-orbit Rashba torque. The chiral symmetry breaking due to the Dzyaloshinskii-Moriya interaction leads to the opposite directions of the domain wall motion in left- or right-handed helices. Furthermore, for the magnetic helices, the emergent effective anisotropy term and Dzyaloshinskii-Moriya interaction can be attributed to the clear geometrical parameters like curvature and torsion offering intuitive understanding of the complex curvilinear effects in magnetism.

  16. An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates.

    Science.gov (United States)

    Sibaev, M; Crittenden, D L

    2016-06-01

    In this paper, we outline a general, scalable, and black-box approach for calculating high-order strongly coupled force fields in rectilinear normal mode coordinates, based upon constructing low order expansions in curvilinear coordinates with naturally limited mode-mode coupling, and then transforming between coordinate sets analytically. The optimal balance between accuracy and efficiency is achieved by transforming from 3 mode representation quartic force fields in curvilinear normal mode coordinates to 4 mode representation sextic force fields in rectilinear normal modes. Using this reduced mode-representation strategy introduces an error of only 1 cm(-1) in fundamental frequencies, on average, across a sizable test set of molecules. We demonstrate that if it is feasible to generate an initial semi-quartic force field in curvilinear normal mode coordinates from ab initio data, then the subsequent coordinate transformation procedure will be relatively fast with modest memory demands. This procedure facilitates solving the nuclear vibrational problem, as all required integrals can be evaluated analytically. Our coordinate transformation code is implemented within the extensible PyPES library program package, at http://sourceforge.net/projects/pypes-lib-ext/.

  17. An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates.

    Science.gov (United States)

    Sibaev, M; Crittenden, D L

    2016-06-01

    In this paper, we outline a general, scalable, and black-box approach for calculating high-order strongly coupled force fields in rectilinear normal mode coordinates, based upon constructing low order expansions in curvilinear coordinates with naturally limited mode-mode coupling, and then transforming between coordinate sets analytically. The optimal balance between accuracy and efficiency is achieved by transforming from 3 mode representation quartic force fields in curvilinear normal mode coordinates to 4 mode representation sextic force fields in rectilinear normal modes. Using this reduced mode-representation strategy introduces an error of only 1 cm(-1) in fundamental frequencies, on average, across a sizable test set of molecules. We demonstrate that if it is feasible to generate an initial semi-quartic force field in curvilinear normal mode coordinates from ab initio data, then the subsequent coordinate transformation procedure will be relatively fast with modest memory demands. This procedure facilitates solving the nuclear vibrational problem, as all required integrals can be evaluated analytically. Our coordinate transformation code is implemented within the extensible PyPES library program package, at http://sourceforge.net/projects/pypes-lib-ext/. PMID:27276945

  18. Multiphasic interactions between nucleotides and target proteins

    CERN Document Server

    Nissen, Per

    2016-01-01

    The nucleotides guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) bind to target proteins to promote bacterial survival (Corrigan et al. 2016). Thus, the binding of the nucleotides to RsgA, a GTPase, inhibits the hydrolysis of GTP. The dose response, taken to be curvilinear with respect to the logarithm of the inhibitor concentration, is instead much better (P<0.001 when the 6 experiments are combined) represented as multiphasic, with high to exceedingly high absolute r values for the straight lines, and with transitions in the form of non-contiguities (jumps). Profiles for the binding of radiolabeled nucleotides to HprT and Gmk, GTP synthesis enzymes, were, similarly, taken to be curvilinear with respect to the logarithm of the protein concentration. However, the profiles are again much better represented as multiphasic than as curvilinear (the P values range from 0.047 to <0.001 for each of the 8 experiments for binding of ppGpp and pppGpp to HprT). The binding of GTP to HprT and ...

  19. Nonlinear effects of team tenure on team psychological safety climate and climate strength: Implications for average team member performance.

    Science.gov (United States)

    Koopmann, Jaclyn; Lanaj, Klodiana; Wang, Mo; Zhou, Le; Shi, Junqi

    2016-07-01

    The teams literature suggests that team tenure improves team psychological safety climate and climate strength in a linear fashion, but the empirical findings to date have been mixed. Alternatively, theories of group formation suggest that new and longer tenured teams experience greater team psychological safety climate than moderately tenured teams. Adopting this second perspective, we used a sample of 115 research and development teams and found that team tenure had a curvilinear relationship with team psychological safety climate and climate strength. Supporting group formation theories, team psychological safety climate and climate strength were higher in new and longer tenured teams compared with moderately tenured teams. Moreover, we found a curvilinear relationship between team tenure and average team member creative performance as partially mediated by team psychological safety climate. Team psychological safety climate improved average team member task performance only when team psychological safety climate was strong. Likewise, team tenure influenced average team member task performance in a curvilinear manner via team psychological safety climate only when team psychological safety climate was strong. We discuss theoretical and practical implications and offer several directions for future research. (PsycINFO Database Record

  20. Veias do sistema porta-hepático em gansos domésticos Veins from hepatic portal vein system in domestic geese

    Directory of Open Access Journals (Sweden)

    Tatiana C. Santos

    2009-04-01

    Full Text Available A distribuição intraparenquimal das veias porta-hepáticas foi estudada em 30 gansos domésticos. Latex Neoprene corado foi injetado pela veia isquiática e os animais forma fixados por imersão e injeção intramuscular com formol a 10% e dissecados. O fígado esteve composto por um grande lobo hepático direito e por um lobo hepático esquerdo menor, os quais estiveram conectados por uma ponte de parênquima. O lobo direito do fígado teve exclusivamente vasos do sistema porta-hepático formados pela distribuição intraparenquimal da veia porta-hepática direita, enquanto que no lobo esquerdo estes originaram-se da veia porta-hepática direita e de pequenas veias porta-hepáticas esquerdas. A veia porta-hepática direita emitiu o ramo caudal direito, que emitiu um pequeno ramo caudolateral direito e um grande ramo caudomedial direito. Cranialmente esta veia emitiu os ramos craniais direito e ramos lateral direito. A porção transversa da veia porta-hepática direita cruzou para o lobo hepático esquerdo, emitindo de 1 a 6 pequenos ramos craniais e caudais para a região média do fígado. No lobo esquerdo, o ramo esquerdo da veia porta-hepática direita emitiu o ramo cranial esquerdo, o ramo lateral esquerdo e o ramo medial. De 1 a 6 veias porta-hepáticas esquerdas foram identificadas desembocando ou no ramo esquerdo da veia porta-hepática direita ou em sua porção transversa, oriundos do ventrículo gástrico e do pró-ventrículo. Em 40% dos gansos uma veia porta-hepática própria oriunda da confluência de vasos venosos da face esquerda do ventrículo distribuiu-se na extremidade caudal do lobo esquerdo isoladamente.The intraparenchymal distribution of the hepatic portal veins in 30 domestic geese were studied. Stained Neoprene latex was injected into the isquiatic vessels, and the animals were fixed in 10% formaldehyde by immersion and intramuscular injection. The liver of geese was composed of a large right and a smaller left

  1. Combinatorial expression of Lef1, Lhx2, Lhx5, Lhx9, Lmo3, Lmo4, and Prox1 helps to identify comparable subdivisions in the developing hippocampal formation of mouse and chicken

    Directory of Open Access Journals (Sweden)

    Antonio eAbellán

    2014-07-01

    Full Text Available We carried out a study of the expression patterns of seven developmental regulatory genes (Lef1, Lhx2, Lhx9, Lhx5, Lmo3, Lmo4, and Prox1, in combination with topological position, to identify the medial pallial derivatives, define its major subdivisions, and compare them between mouse and chicken. In both species, the medial pallium is defined as a pallial sector adjacent to the cortical hem and roof plate/choroid tela, showing moderate to strong ventricular zone expression of Lef1, Lhx2 and Lhx9, but not Lhx5. Based on this, the hippocampal formation (indusium griseum, dentate gyrus, Ammon’s horn fields, and subiculum, the medial entorhinal cortex, and part of the amygdalo-hippocampal transition area of mouse appeared to derive from the medial pallium. In the chicken, based on the same position and gene expression profile, we propose that the hippocampus (including the V-shaped area, the parahippocampal area (including its caudolateral part, the entorhinal cortex, and the amygdalo-hippocampal transition area are medial pallial derivatives. Moreover, the combinatorial expression of Lef1, Prox1, Lmo4 and Lmo3 allowed the identification of dentate gyrus/CA3-like, CA1/subicular-like, and medial entorhinal-like comparable sectors in mouse and chicken, and point to the existence of mostly conserved molecular networks involved in hippocampal complex development. Notably, while the mouse medial entorhinal cortex derives from the medial pallium (similarly to the hippocampal formation, both being involved in spatial navigation and spatial memory, the lateral entorhinal cortex (involved in processing non-spatial, contextual information appears to derive from a distinct dorsolateral caudal pallial sector.

  2. Sex differences in the representation of call stimuli in a songbird secondary auditory area.

    Science.gov (United States)

    Giret, Nicolas; Menardy, Fabien; Del Negro, Catherine

    2015-01-01

    Understanding how communication sounds are encoded in the central auditory system is critical to deciphering the neural bases of acoustic communication. Songbirds use learned or unlearned vocalizations in a variety of social interactions. They have telencephalic auditory areas specialized for processing natural sounds and considered as playing a critical role in the discrimination of behaviorally relevant vocal sounds. The zebra finch, a highly social songbird species, forms lifelong pair bonds. Only male zebra finches sing. However, both sexes produce the distance call when placed in visual isolation. This call is sexually dimorphic, is learned only in males and provides support for individual recognition in both sexes. Here, we assessed whether auditory processing of distance calls differs between paired males and females by recording spiking activity in a secondary auditory area, the caudolateral mesopallium (CLM), while presenting the distance calls of a variety of individuals, including the bird itself, the mate, familiar and unfamiliar males and females. In males, the CLM is potentially involved in auditory feedback processing important for vocal learning. Based on both the analyses of spike rates and temporal aspects of discharges, our results clearly indicate that call-evoked responses of CLM neurons are sexually dimorphic, being stronger, lasting longer, and conveying more information about calls in males than in females. In addition, how auditory responses vary among call types differ between sexes. In females, response strength differs between familiar male and female calls. In males, temporal features of responses reveal a sensitivity to the bird's own call. These findings provide evidence that sexual dimorphism occurs in higher-order processing areas within the auditory system. They suggest a sexual dimorphism in the function of the CLM, contributing to transmit information about the self-generated calls in males and to storage of information about the

  3. Affective and cognitive prefrontal cortex projections to the lateral habenula in humans.

    Directory of Open Access Journals (Sweden)

    Karin eVadovičová

    2014-10-01

    Full Text Available Anterior insula (AI and dorsal ACC (dACC are known to process information about pain, loss, adversities, bad, harmful or suboptimal choices and consequences that threaten survival or well-being. Also pregenual ACC (pgACC is linked to loss and pain, being activated by sad thoughts and regrets. Lateral habenula (LHb is stimulated by predicted and received pain, discomfort, aversive outcome, loss. Its chronic stimulation makes us feel worse/low and gradually stops us choosing and moving for the suboptimal or punished choices, by direct and indirect (via rostromedial tegmental nucleus RMTg inhibition of DRN and VTA/SNc. The response selectivity of LHb neurons suggests their cortical input from affective and cognitive evaluative regions that make expectations about bad, unpleasant or suboptimal outcomes. Based on these facts we predicted direct dACC, pgACC and AI projections to LHb, which form part of an adversity processing circuit that learns to avoid bad outcomes by suppressing dopamine and serotonin signal. To test this connectivity we used Diffusion Tensor Imaging (DTI. We found dACC, pgACC, AI and caudolateral OFC projections to LHb. We predicted no corticohabenular projections from the reward processing regions: medial OFC (mOFC and ventral ACC (vACC because both respond most strongly to good, high valued stimuli and outcomes, inducing dopamine and serotonin release. This lack of LHb projections was confirmed for vACC and likely for mOFC. The surprising findings were the corticohabenular projections from the cognitive prefrontal cortex regions, known for flexible reasoning, planning and combining whatever information are relevant for reaching current goals. We propose that the prefrontohabenular projections provide a teaching signal for value-based choice behaviour, to learn to deselect, avoid or inhibit the potentially harmful, low valued or wrong choices, goals, strategies, predictions and ways of doing things, to prevent bad or suboptimal

  4. Development and distribution of PAG-immunoreactive neurons in the central pathway of trigeminal proprioception of the rat brainstem

    Institute of Scientific and Technical Information of China (English)

    PANG You-wang; LI Jin-lian

    2002-01-01

    Objective:To investigate the development and distribution of phosphate-activated glutaminase like immunoreactive (PAG-LI) neurons in the central pathway of trigeminal proprioception of the rat brainstem.Methods: The immunohistochemitry techniques were used. Results: (1) At embryonic day 17 (E17), PAGLI neurons were initially observed in the mesencephalic trigeminal nucleus (Vme). All PAG-LI neurons were large round neurons with moderate immunostaining. The immunoreactivity grew intense and attained adultlike pattern at P10. (2) Not until postnatal day 10 (P10) did a few PAG-LI neurons appear in the area ventral to the motor trigeminal nucleus (AVM) and area dorsal to the superior olivery nucleus (ADO), and not until P12 in the dorsomedial part of the subnucleus oralis of the spinal trigeminal nucleus (Vodm) and dorsomedial part of the principal sensory trigeminal nucleus (Vpdm). As development proceeded, more and more neurons in them were immunostained, and some PAG-LI neurons were detected in the lateral reticular formation adjacent to the Vodm(LRF)and the caudolateral part of the supratrigeminal nucleus (Vsup-CL) at P21.Conclusion: In the central pathway of trigeminal proprioception of the rat brainstem, PAG-LI neurons appeared during two stages: The first stage from E17 to P10, PAG-LI neurons appeared in the Vme and reached adult-like pattern; the second stage from P10 to P21, PAG-LI neurons appeared in the Vodm, LRF,Vpdm, Vsup-CL, ADO, AVM and gradually reached adult-like pattern. This might be relative to the establishment of jaw movement patterns.

  5. Revisiting the supratrigeminal nucleus in the rat.

    Science.gov (United States)

    Fujio, T; Sato, F; Tachibana, Y; Kato, T; Tomita, A; Higashiyama, K; Ono, T; Maeda, Y; Yoshida, A

    2016-06-01

    The supratrigeminal nucleus (Vsup), originally proposed as a premotoneuron pool in the trigeminal reflex arc, is a key structure of jaw movement control. Surprisingly, however, the location of the rat Vsup has not precisely been defined. In light of our previous cat studies, we made two hypotheses regarding the rat Vsup: (1) the Vsup is cytoarchitectonically distinguishable from its surrounding structures; (2) the Vsup receives central axon terminals of the trigeminal mesencephalic nucleus (Vmes) neurons which are primary afferents innervating muscle spindles of jaw-closing muscles and periodontal ligaments around the teeth. To test the first hypothesis, we examined the cytoarchitecture of the rat Vsup. The Vsup was identified as an area medially adjacent to the dorsomedial part of trigeminal principal sensory nucleus (Vp), and extended from the level just rostral to the caudal two-thirds of the trigeminal motor nucleus (Vmo) to the level approximately 150μm caudal to the Vmo. Our rat Vsup was much smaller and its location was considerably different in comparison to the Vsup reported previously. To evaluate the second hypothesis, we tested the distribution patterns of Vmes primary afferent terminals in the cytoarchitectonically identified Vsup. After transganglionic tracer applications to the masseter, deep temporal, and medial pterygoid nerves, a large number of axon terminals were observed in all parts of Vsup (especially in its medial part). After applications to the inferior alveolar, infraorbital, and lingual nerves, a small number of axon terminals were labeled in the caudolateral Vsup. The Vsup could also be identified electrophysiologically. After electrical stimulation of the masseter nerve, evoked potentials with slow negative component were isolated only in the Vsup. The present findings suggest that the rat Vsup can be cytoarchitectonically and electrophysiologically identified, receives somatotopic termination of the trigeminal primary afferents, and

  6. Organization of sensory cortex in the East African hedgehog (Atelerix albiventris).

    Science.gov (United States)

    Catania, K C; Collins, C E; Kaas, J H

    2000-05-29

    We investigated the organization of neocortex in the East African hedgehog (Atelerix albiventris) with microelectrode recordings from sensory areas that were later correlated with cytochrome oxidase patterns in sections of flattened cortex. The location of corticospinal projecting neurons was also examined and related to sensory areas by making small injections of wheat germ agglutinin-horseradish peroxidase into the spinal cord. Our goals were to determine how hedgehog cortex is organized, how much sensory areas overlap, and to compare results with recent findings in other insectivores. Evidence was found for three separate topographically organized somatosensory areas, two visual areas, and a caudolateral auditory area. A medial somatosensory area corresponded to S1, the primary somatosensory area, whereas two lateral areas partially encircled auditory cortex and corresponded to the parietal ventral area (PV) and the secondary somatosensory area (S2). Primary visual cortex (V1) was delineated by a caudomedial cytochrome oxidase dark oval, and a more lateral visual area between V1 and somatosensory cortex corresponded to V2, or area 18. Two patches of corticospinal projecting cells were found primarily overlapping S1 and S2. Some bimodal auditory and somatosensory responses were found in parts of PV and S2, but for the most part, areas had relatively sharp histochemically apparent and physiologically defined borders. The present results indicate that the caudal neocortex of hedgehogs has only a few sensory areas, corresponding to those commonly found in several other small-brained mammals. Hedgehog cortical organization differs significantly in somatotopy, number, and position of fields from that of closely related shrews and moles. Thus, clear specializations occur, even within the order Insectivora. PMID:10813786

  7. Radiographic imaging of the canine intercondylar fossa

    International Nuclear Information System (INIS)

    The intercondylar fossa is believed to play an important role in the pathology of cranial cruciate ligament rupture and therefore has received considerable attention in the last decade. Accurate radiographic imaging of the intercondylar fossa requires that the central x-ray beam pass through the center of the intercondylar “tunnel”. The anatomy of the canine intercondylar fossa is similar to humans, however, the orientations of the intercondylar fossa's differ. Consequently, the positioning techniques described for humans are not appropriate for the dog. To pass through the center of the dog, intercondylar fossa, the central x-ray beam should be 12° (S.D. 1.7°) caudal from the femoral diaphysis in the sagittal plane and obliqued caudolateral to craniomedial 7° (S.D. 0.60°) (caudo78°proximo7° lateralcraniodistomedial oblique). Cross table positioning was used with the hip flexed and the radiograph cassette placed on the cranial surface of the stifle. However, superimposition of the tuber ischii and soft tissues caudal to the femur made 15° to 20° the best angle obtainable. There was not a significant difference (p = 0.17) in the notch width index between a 12° versus 20° angle of the central x-ray beam caudal to the femoral diaphysis, both with 7° of external rotation of the stifle. The notch width index of 0.252 obtained from radiographic measurements was not significantly different from measurements obtained grossly of 0.254 (n = 26; p = 0.69). Failure to oblique the central x-ray beam caused a significant (p = 0.0008) decrease in the apparent fossa width radiographically

  8. Sex differences in the representation of call stimuli in a songbird secondary auditory area

    Directory of Open Access Journals (Sweden)

    Nicolas eGiret

    2015-10-01

    Full Text Available Understanding how communication sounds are encoded in the central auditory system is critical to deciphering the neural bases of acoustic communication. Songbirds use learned or unlearned vocalizations in a variety of social interactions. They have telencephalic auditory areas specialized for processing natural sounds and considered as playing a critical role in the discrimination of behaviorally relevant vocal sounds. The zebra finch, a highly social songbird species, forms lifelong pair bonds. Only male zebra finches sing. However, both sexes produce the distance call when placed in visual isolation. This call is sexually dimorphic, is learned only in males and provides support for individual recognition in both sexes. Here, we assessed whether auditory processing of distance calls differs between paired males and females by recording spiking activity in a secondary auditory area, the caudolateral mesopallium (CLM, while presenting the distance calls of a variety of individuals, including the bird itself, the mate, familiar and unfamiliar males and females. In males, the CLM is potentially involved in auditory feedback processing important for vocal learning. Based on both the analyses of spike rates and temporal aspects of discharges, our results clearly indicate that call-evoked responses of CLM neurons are sexually dimorphic, being stronger, lasting longer and conveying more information about calls in males than in females. In addition, how auditory responses vary among call types differ between sexes. In females, response strength differs between familiar male and female calls. In males, temporal features of responses reveal a sensitivity to the bird’s own call. These findings provide evidence that sexual dimorphism occurs in higher-order processing areas within the auditory system. They suggest a sexual dimorphism in the function of the CLM, contributing to transmit information about the self-generated calls in males and to storage of

  9. High-resolution ultrasound biomicroscopy for monitoring ovarian structures in mice

    Directory of Open Access Journals (Sweden)

    Singh Jaswant

    2009-07-01

    Full Text Available Abstract Background Until recently, the limit of spatial resolution of ultrasound systems has prevented characterization of structures Methods Experiment 1 was a pilot study to develop methods of immobilization (physical restraint vs. general anesthesia and determine technical factors affecting ovarian images using ultrasound bio-microscopy in rats vs. mice. The hair coat was removed over the thoraco-lumber area using depilation cream, and a highly viscous acoustic gel was applied while the animals were maintained in sternal recumbency. In Experiment 2, changes in ovarian structures during the estrous cycle were monitored by twice daily ultrasonography in 10 mice for 2 estrous cycles. Results Ovarian images were not distinct in rats due to attenuation of ultrasound waves. Physical restraint, without general anesthesia, was insufficient for immobilization in mice. By placing the transducer face over the dorsal flank, the kidney was visualized initially as a point of reference. A routine of moving the transducer a few millimetres caudo-laterally from the kidney was established to quickly and consistently localize the ovaries; the total time to scan both ovaries in a mouse was about 10 minutes. By comparing vaginal cytology with non-anesthetized controls, repeated exposure to anesthesia did not affect the estrous cycle. Temporal changes in the number of follicles in 3 different size categories support the hypothesis that follicles ≥ 20 microns develop in a wave-like fashion. Conclusion The mouse is a suitable model for the study of ovarian dynamics using transcutaneous ultrasound bio-microscopy. Repeated general anesthesia for examination had no apparent effect on the estrous cycle, and preliminary results revealed a wave-like pattern of ovarian follicle development in mice.

  10. Reference guide to WPP version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, A; Sjogreen, B

    2010-01-22

    WPP is a computer program for simulating seismic wave propagation on parallel machines. WPP solves the governing equations in second order formulation using a node-based finite difference approach. The basic numerical method is described in [9]. WPP implements substantial capabilities for 3-D seismic modeling, with a free surface condition on the top boundary, non-reflecting far-field boundary conditions on the other boundaries, point force and point moment tensor source terms with many predefined time dependencies, fully 3-D heterogeneous material model specification, output of synthetic seismograms in the SAC [4] format, output of GMT [11] scripts for laying out simulation information on a map, and output of 2-D slices of (derived quantites of) the solution field as well as the material model. Version 2.0 of WPP allows the free surface boundary condition to be imposed on a curved topography. For this purpose a curvilinear mesh is used near the free surface, extending into the computational domain down to a user specified level. The elastic wave equations and the free surface boundary conditions are discretized on the curvilinear mesh using the energy conserving technique described in [2]. A curvilinear mesh generator is built into WPP and the curvilinear mesh is automatically generated from the topography. Below the curvilinear grid, the elastic wave equation is discretized on Cartesian meshes, which leads to a more computationally efficient algorithm. In version 2.0 of WPP, Cartesian local mesh refinement can be used to make the computational mesh finer near the free surface, where more resolution often is needed to resolve short wave lenghts in the solution, for example in sedimentary basins. The mesh refinement is performed in the vertical direction and each Cartesian grid is constructed from user specified refinement levels. In this approach, the grid size in all three spatial directions is doubled across each mesh refinement interface, leading to substantial

  11. A MULTICENTER, BLIND, RANDOMIZED, PLACEBO-CONTROLLED STUDY OF THE SYMPTOM- AND STRUCTURE-MODIFYING EFFET OF ALFLUTOP IN PATIENTS WITH KNEE OSTEOARTHRITIS. REPORT 2: THE ASSESSMENT OF THE STRUCTURE-MODIFYING EFFECT OF THE DRUG

    Directory of Open Access Journals (Sweden)

    L. I. Alekseeva

    2014-01-01

    Full Text Available Objective. To evaluate the symptom- and structure-modifying effect of Alflutop compared to placebo (PL in patients with knee osteoarthritis (OA. Material and methods. The study included 90 patients with knee OA (according to the criteria of the Russian Association of Rheumatologists at the stage 2–3 (according to the Kellgren-Lawrence scale; pain score when walk- ing ≥ 40 mm (assessed using the visual analog scale. All the patients provided an informed consent. The patients were randomly divided into two groups: group 1 (n=45 received an intramuscular injection of 1 mL Alflutop for 20 days with 6-month intervals for 2 years (a total of 4 courses for 2 years; group 2 (n=45 received an injection of PL (iso- tonic sodium chloride solution in the same way. Ibuprofen at a dose of 600–1200 mg/day was administered as concomitant therapy. To evaluate the structure-modifying effect of Alflutop, X-ray of the knee joint was performed at the beginning and end of the study; the level of biochemical markers (CTX-II and COMP was determined at the beginning, after 3 months, and at the end of the study. A statistical analysis was performed using the Statistica 10 software package.Results. After the 2-year follow-up, a statistically significant negative trend was detected less frequently in the group of patients treated with Alflutop compared to the PL group (6.1 and 38.4%, respectively. The statistically significant delay in joint space narrowing was observed in patients who received Alflutop in contrast to patients who received PL (the numerical score of the joint space, the Wilcoxon test; p=0.0003. An increase in osteo- phyte size was observed in 72% of the patients receiving PL, and only in 27% of the patients receiving Alflutop (medial and lateral osteophytes of the femoral bone, the Wilcoxon test; p=0.0078; medial and lateral osteophytes of the shin bone, the Wilcoxon test; p=0.0001 and p=0.0039, respective- ly. Augmentation of subchondral

  12. Further evidence for epidemiological transition hypothesis for elderly suicides

    Directory of Open Access Journals (Sweden)

    Ajit Shah

    2011-01-01

    Full Text Available BACKGROUND: A developmental model of epidemiological transition for elderly suicide rates with four sequential stages has been developed to simultaneously explain cross-national variations in elderly suicide rates, trends over time for elderly suicide rates and age-associated trends in suicides rates reported in the literature. This model was supported by demonstration of a curvilinear (inverted U-shaped curve relationship between elderly suicide rates and socio-economic status fitting the quadratic equation Y = A + BX - CX2 (where Y is the suicide rate, X is the socio-economic status and A,B, and C are constants in both sexes. However, this relationship was derived from a cross-sectional study and, therefore, only an association can be inferred. One way to substantiate this further would be to examine the above curvilinear relationship between suicide rates and socio-economic status in a series of younger age-bands because a large part of the epidemiological transition hypothesis was contingent upon the impact of socio-economic status, through a series of mechanisms, on life expectancy. It was hypothesized that the curvilinear (inverted U-shaped curve relationship between suicide rates and socio-economic status would be absent in younger age-bands and may be present in the younger age-bands closer to the older age-bands (i.e. 45-54 years and 55-64 years. METHODS: The curvilinear relationship between suicide rates in five age-bands 15-24 years to 55-64 years in both sexes and gross national domestic product (GDP, a measure of socio-economic status, fitting the above quadratic equation was examined with curve estimation regression model using data from the World Health Organization. RESULTS: In males in the age-bands 35-44 years, 45-54 years and 55-64 years there was a statistically significant curvilinear (inverted U-shaped curve relationship with GDP and fitted the quadratic equation Y = A + BX - CX2; this relationship was absent in males in

  13. 股骨髋臼撞击症的CT表现分析%CT analysis of femoroacetabular impingement

    Institute of Scientific and Technical Information of China (English)

    宋国勇; 李石玲; 赵建; 郭智萍; 张伟; 卢军丽

    2013-01-01

    Objective To analyze the characteristic appearances on CT of hips with femoroacetabular impingement so as to find CT imaging features. Methods 22 hips with femoroacetabular impingement were classified, imaging features were analysed. Results Study group of 22 hips with femoroacetabular impingement was divided into cam type group (n=12) and pincer type group (n=10). The imaging features of CT involved acetabular proliferations and sclerosis, abnormol sub-articular bone density, nonsmooth articular surfaces and femoral heads with osteophyte and so on. The last two showed significant difference between cam type group and pincer type group. Conclusion The significant difference of FAI groups in nonsmooth articular surfaces and femoral heads with osteophyte explained different pathogenic mechanism. It is important for the diagnosis of FAI to comprehensively analyze imaging features and medical history.%目的 通过观察分析确诊为股骨髋臼撞击症的髋关节的CT表现,找出其影像特点.方法 对22侧(21例)髋关节的CT图像进行了分类和影像征象分析.结果 22侧股骨髋臼撞击症髋关节,杵型12侧,臼型10侧.以股骨头骨赘、髋臼缘硬化增生、关节面失光滑、关节面下密度异常四项CT征象做为杵型组和臼型组的对照指标,股骨头骨赘和关节面失光滑有明显差别.结论 股骨头骨赘和关节面失光滑这些指标都反映了致病机制的差异.股骨髋臼撞击症的诊断,需要综合考虑临床病史及影像征象.

  14. Patients with problems after ACL reconstruction - what do help MRI and SPECT/CT?

    Science.gov (United States)

    Mathis, Dominic T.; Hirschmann, Michael T.; Rasch, Helmut; Falkowski, Anna; Hirschmann, Anna

    2016-01-01

    Aims and Objectives: Magnetic resonance imaging (MRI) and single-photon emission computed tomography/ computed tomography (SPECT/CT) are established diagnostic instruments for symptomatic patients after ACL reconstruction. The purpose of the study was to compare and correlate MRI and SPECT/CT findings of symptomatic patients after ACL reconstruction. Materials and Methods: In a retrospective study 30 knees of symptomatic patients complaining about pain and/or instability after ACL reconstruction were investigated using 99mTc-HDP SPECT/CT and MRI. In MRI signs of a graft tear (partial and complete) were noted. Graft signal intensity, bone bruise, cyst formation in proximal, medial and distal femoral and tibial tunnels, roof impingement, roof osteophytes, graft arthrofibrosis, knee joint effusion and synovial thickness were classified. Measurements were performed by two musculoskeletal radiologists. The agreement of the assessed MR signs were calculated using cohen’s kappa coefficient. These showed excellent (kappa >0.75) to good (kappa >0.40) reproducibility between the readings of the two observers. Quantitative grading of bone tracer uptake (BTU) for each anatomical area of a previously validated localisation scheme was done. Tunnel width was assessed in CT at three different levels for femoral and tibial tunnels. The findings in SPECT/CT and MRI were correlated (pknee regions was found in patients with MR findings of knee joint effusion, synovial thickening and bone bruise in various knee regions. A reciprocal correlation was shown for cyst formation in the central and distal area of the femoral tunnel and BTU in the femoral tunnel. MR findings such as graft continuity, graft signal intensity in the femoral and tibial tunnel, roof impingement, roof osteophytes did not show a significant correlation. A reciprocal correlation was revealed for tunnel enlargement in the proximal and central femoral tunnel and MR signal intensity in the entire intra-articular graft

  15. Three-Dimensional Quantitative Morphometric Analysis (QMA for In Situ Joint and Tissue Assessment of Osteoarthritis in a Preclinical Rabbit Disease Model.

    Directory of Open Access Journals (Sweden)

    Kathryn S Stok

    Full Text Available This work utilises advances in multi-tissue imaging, and incorporates new metrics which define in situ joint changes and individual tissue changes in osteoarthritis (OA. The aims are to (1 demonstrate a protocol for processing intact animal joints for microCT to visualise relevant joint, bone and cartilage structures for understanding OA in a preclinical rabbit model, and (2 introduce a comprehensive three-dimensional (3D quantitative morphometric analysis (QMA, including an assessment of reproducibility. Sixteen rabbit joints with and without transection of the anterior cruciate ligament were scanned with microCT and contrast agents, and processed for histology. Semi-quantitative evaluation was performed on matching two-dimensional (2D histology and microCT images. Subsequently, 3D QMA was performed; including measures of cartilage, subchondral cortical and epiphyseal bone, and novel tibio-femoral joint metrics. Reproducibility of the QMA was tested on seven additional joints. A significant correlation was observed in cartilage thickness from matching histology-microCT pairs. The lateral compartment of operated joints had larger joint space width, thicker femoral cartilage and reduced bone volume, while osteophytes could be detected quantitatively. Measures between the in situ tibia and femur indicated an altered loading scenario. High measurement reproducibility was observed for all new parameters; with ICC ranging from 0.754 to 0.998. In conclusion, this study provides a novel 3D QMA to quantify macro and micro tissue measures in the joint of a rabbit OA model. New metrics were established consisting of: an angle to quantitatively measure osteophytes (σ, an angle to indicate erosion between the lateral and medial femoral condyles (ρ, a vector defining altered angulation (λ, α, β, γ and a twist angle (τ measuring instability and tissue degeneration between the femur and tibia, a length measure of joint space width (JSW, and a slope and

  16. Arthroscopic debridement of osteoarthritic elbow in professional athletes

    Institute of Scientific and Technical Information of China (English)

    YAN Hui; CUI Guo-qing; WANG Jian-quan; YIN Yu; AO Ying-fang

    2011-01-01

    Background Arthroscopic debridement is an appropriate procedure for osteoarthritic elbow in general populations.However,the results of arthroscopic debridement in the professional athletes,a younger and highly active patient cohort is unclear.The purposes of this study were to assess the clinical outcomes of arthroscopic debridement of osteoarthritic elbow in professional athletes and to evaluate the effect of prognostic factors on the clinical outcomes.Methods From January 1999 to January 2006,35 professional athletes with osteoarthritc elbow (36 elbows) were treated with arthroscopic debridement,consisted of osteophytes removal,loose bodies removal and fenestration of the olecranon fossa as necessary.Average patient age was (23±5) years (range 7-34 years).Average follow-up was (43±23) months (range 16-98 months).Athletic activities consisted mainly of wrestling,judo and weightlifting.Patients were evaluated preoperatively and postoperatively with the modified Hospital for Special Surgery (HSS) elbow scoring system.Results According to the modified HSS elbow scoring system,the result was excellent for 16 elbows,good for 14 and poor for 6.No case had got worse after surgery.All athletes reported an improvement in pain.After athletic training,15 elbows were not painful,16 mildly painful,3 moderately painful and 2 severely painful.The arc of flexion-extension improved from 111 ° preoperatively to 127° postoperatively.All of the athletes were able to return to their previous level of training.Five athletes won national-level championships.At follow-up,17 athletes (18 elbows) were greatly satisfied with the results,12 satisfied and 6 unsatisfied.Postoperatively,one athlete reported ulnar nerve symptoms and two others had residual loose bodies.The fenestration of the olecranon fossa was associated with a significantly increased chance of a poor outcome.The nature of the osteoarthritis,duration of symptoms,osteophytes removal and loose bodies removal did not predict

  17. Evaluating conducting network based transparent electrodes from geometrical considerations

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ankush [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, 560064 Bangalore (India); Kulkarni, G. U., E-mail: guk@cens.res.in [Centre for Nano and Soft Matter Sciences, 560013 Bangalore (India)

    2016-01-07

    Conducting nanowire networks have been developed as viable alternative to existing indium tin oxide based transparent electrode (TE). The nature of electrical conduction and process optimization for electrodes have gained much from the theoretical models based on percolation transport using Monte Carlo approach and applying Kirchhoff's law on individual junctions and loops. While most of the literature work pertaining to theoretical analysis is focussed on networks obtained from conducting rods (mostly considering only junction resistance), hardly any attention has been paid to those made using template based methods, wherein the structure of network is neither similar to network obtained from conducting rods nor similar to well periodic geometry. Here, we have attempted an analytical treatment based on geometrical arguments and applied image analysis on practical networks to gain deeper insight into conducting networked structure particularly in relation to sheet resistance and transmittance. Many literature examples reporting networks with straight or curvilinear wires with distributions in wire width and length have been analysed by treating the networks as two dimensional graphs and evaluating the sheet resistance based on wire density and wire width. The sheet resistance values from our analysis compare well with the experimental values. Our analysis on various examples has revealed that low sheet resistance is achieved with high wire density and compactness with straight rather than curvilinear wires and with narrower wire width distribution. Similarly, higher transmittance for given sheet resistance is possible with narrower wire width but of higher thickness, minimal curvilinearity, and maximum connectivity. For the purpose of evaluating active fraction of the network, the algorithm was made to distinguish and quantify current carrying backbone regions as against regions containing only dangling or isolated wires. The treatment can be helpful in

  18. Tracing the Chromospheric and Coronal Magnetic Field with AIA, IRIS, IBIS, and ROSA Data

    Science.gov (United States)

    Aschwanden, Markus J.; Reardon, Kevin; Jess, Dave B.

    2016-07-01

    The aim of this study is to explore the suitability of chromospheric images for magnetic modeling of active regions. We use high-resolution images (≈ 0\\buildrel{\\prime\\prime}\\over{.} 2{--}0\\buildrel{\\prime\\prime}\\over{.} 3), from the Interferometric Bidimensional Spectrometer in the Ca ii 8542 Å line, the Rapid Oscillations in the Solar Atmosphere instrument in the Hα 6563 Å line, the Interface Region Imaging Spectrograph in the 2796 Å line, and compare non-potential magnetic field models obtained from those chromospheric images with those obtained from images of the Atmospheric Imaging Assembly in coronal (171 Å, etc.) and in chromospheric (304 Å) wavelengths. Curvi-linear structures are automatically traced in those images with the OCCULT-2 code, to which we forward-fitted magnetic field lines computed with the Vertical-current Approximation Nonlinear Force Free Field code. We find that the chromospheric images: (1) reveal crisp curvi-linear structures (fibrils, loop segments, spicules) that are extremely well-suited for constraining magnetic modeling; (2) that these curvi-linear structures are field-aligned with the best-fit solution by a median misalignment angle of {μ }2≈ 4^\\circ –7° (3) the free energy computed from coronal data may underestimate that obtained from cromospheric data by a factor of ≈ 2–4, (4) the height range of chromospheric features is confined to h≲ 4000 km, while coronal features are detected up to h = 35,000 km; and (5) the plasma-β parameter is β ≈ {10}-5{--}{10}-1 for all traced features. We conclude that chromospheric images reveal important magnetic structures that are complementary to coronal images and need to be included in comprehensive magnetic field models, something that is currently not accomodated in standard NLFFF codes.

  19. Geologic map of the MTM 85200 quadrangle, Olympia Rupes region of Mars

    Science.gov (United States)

    Skinner, James A.; Herkenhoff, Kenneth E.

    2012-01-01

    The north polar region of Mars is dominated by Planum Boreum, a roughly circular, domical plateau that rises >2,500 m above the surrounding lowland. Planum Boreum is >1,500 km in diameter, contains deep, curvilinear troughs and chasmata, isolated cavi, and marginal scarps and slopes. The north polar plateau is surrounded by low-lying and nearly horizontal plains of various surface texture, geologic origin, and stratigraphic significance. The MTM 85200 quadrangle spans 5° of latitude (lat 82.5° to 87.5° N.) and 40° of longitude (long 140° to 180° E.) within the eastern hemisphere of Mars. The quadrangle includes the high-standing Planum Boreum, curvilinear troughs of Boreales Scopuli, deep, sinuous scarps of Olympia Rupes, isolated and coalesced depressions of Olympia Cavi, margins of the circular polar erg Olympia Undae, and low-standing Olympia Planum. The surface of Planum Boreum within the MTM 85200 quadrangle is characterized by smoothly sculptured landforms with shallow slopes and variable relief at kilometer scales. Areas that are perennially covered with bright frost are generally smooth and planar at 100-m scales. However, MGS MOC and MRO HiRISE images show that much of the icy polar plateau is rough at decameter scale. The Martian polar plateaus are likely to contain a record of global climate history for >107 to as much as ~3 x 109 years. This record is partly observable as rhythmically layered deposits exposed in the curvilinear troughs of the north polar plateau, Planum Boreum. The north polar layered deposits are widely interpreted to be among the most youthful bedrock deposits on the Martian surface. These materials and their stratigraphic and structural relations provide a glimpse into some of the more recent geologic processes that have occurred on Mars. The ability of the massive polar deposits to periodically trap and release both volatiles and lithic particles may represent a globally important, recurring geologic process for Mars.

  20. ASSESSMENT OF HYDROCARBON SEEPAGE DETECTION METHODS ON THE FORT PECK RESERVATION, NORTHEAST MONTANA

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence M. Monson

    2003-06-30

    Surface exploration techniques have been employed in separate study areas on the Fort Peck Reservation in northeastern Montana. Anomalies associated with hydrocarbon seepage are documented in all three areas and a variety of surface exploration techniques can be compared. In a small area with established production, Head Gas and Thermal Desorption methods best match production; other methods also map depletion. In a moderate-size area that has prospects defined by 3D seismic data, Head Gas along with Microbial, Iodine, and Eh soil anomalies are all associated with the best hydrocarbon prospect. In a large area that contains many curvilinear patterns observed on Landsat images, that could represent micro-seepage chimneys, results are inconclusive. Reconnaissance mapping using Magnetic Susceptibility has identified a potential prospect; subsequent Soil Gas and Head Gas surveys suggest hydrocarbon potential. In the final year of this project the principle contractor, the Fort Peck Tribes, completed a second survey in the Wicape 3D Seismic Prospect Area (also known as Area 6 in Phase I of the project) and sampled several Landsat image features contained in the Smoke Creek Aeromag Anomaly Area (also known as Area 1 in Phase II of the project). Methods determined to be most useful in Phases I and II, were employed in this final Phase III of the study. The Southwest Wicape seismic anomaly was only partially confirmed. The abundant curvilinears proposed to be possible hydrocarbon micro-seepage chimneys in the Smoke Creek Area were not conclusively verified as such. Insufficient sampling of background data precludes affirmative identification of these mostly topographic Landsat features as gas induced soil and vegetation anomalies. However relatively higher light gas concentrations were found associated with some of the curvilinears. Based on the findings of this work the Assiniboine & Sioux Tribes of the Fort Peck Reservation intend to utilize surface hydrocarbon

  1. Evaluating conducting network based transparent electrodes from geometrical considerations

    Science.gov (United States)

    Kumar, Ankush; Kulkarni, G. U.

    2016-01-01

    Conducting nanowire networks have been developed as viable alternative to existing indium tin oxide based transparent electrode (TE). The nature of electrical conduction and process optimization for electrodes have gained much from the theoretical models based on percolation transport using Monte Carlo approach and applying Kirchhoff's law on individual junctions and loops. While most of the literature work pertaining to theoretical analysis is focussed on networks obtained from conducting rods (mostly considering only junction resistance), hardly any attention has been paid to those made using template based methods, wherein the structure of network is neither similar to network obtained from conducting rods nor similar to well periodic geometry. Here, we have attempted an analytical treatment based on geometrical arguments and applied image analysis on practical networks to gain deeper insight into conducting networked structure particularly in relation to sheet resistance and transmittance. Many literature examples reporting networks with straight or curvilinear wires with distributions in wire width and length have been analysed by treating the networks as two dimensional graphs and evaluating the sheet resistance based on wire density and wire width. The sheet resistance values from our analysis compare well with the experimental values. Our analysis on various examples has revealed that low sheet resistance is achieved with high wire density and compactness with straight rather than curvilinear wires and with narrower wire width distribution. Similarly, higher transmittance for given sheet resistance is possible with narrower wire width but of higher thickness, minimal curvilinearity, and maximum connectivity. For the purpose of evaluating active fraction of the network, the algorithm was made to distinguish and quantify current carrying backbone regions as against regions containing only dangling or isolated wires. The treatment can be helpful in predicting

  2. The relationship between elderly suicide rates and different components of education: a cross-national study

    Directory of Open Access Journals (Sweden)

    Ajit Shah

    2012-07-01

    Full Text Available BACKGROUND: Two recent studies reported a curvilinear (U-shaped between elderly suicide rates and educational attainment measured by the United Nation’s Education Index. A study examining the curvilinear (U-shaped relationship between elderly suicide rates and the individual components of the Education Index (adult literacy rate, percentage of children of relevant age group enrolled in primary schools and percentage of children of relevant age group enrolled for secondary schools and one other measure of educational attainment (youth literacy rate was undertaken to partial out the effects of the individual components of Education Index on elderly suicides. METHODS: A cross-national study examining the relationship between elderly suicide rates (Y-axis and different measures of educational attainment (X-axis was undertaken using data from the World Health Organization and the United Nations data banks using Curve estimation regression models. RESULTS: The relationship between elderly suicide rates with the adult literacy rate, the percentage of children of relevant age group enrolled for secondary schools and the youth literacy rate was curvilinear (U-shaped curve. This relationship was absent with the percentage of children of relevant age group enrolled in primary schools. CONCLUSIONS: Given the cross-sectional study design, a causal relationship between elderly suicide rates and measures of educational attainment, including the adult literacy rate, the percentage of children of relevant age group enrolled for secondary schools and the youth literacy rate, cannot be assumed. However, the findings suggest that future studies of elderly suicide rates and educational attainment should focus on the adult literacy rate, the percentage of children of relevant age group enrolled for secondary schools and the youth literacy rate as measures of educational attainment.

  3. Sperm treatment affects capacitation parameters and penetration ability of ejaculated and epididymal boar spermatozoa.

    Science.gov (United States)

    Matás, C; Sansegundo, M; Ruiz, S; García-Vázquez, F A; Gadea, J; Romar, R; Coy, P

    2010-11-01

    This work was designed to study how this ability is affected by different sperm treatments routinely used for in vitro fertilization (IVF) assay. In this study, boar sperm samples from epididymal or ejaculated origin were processed by three different methods: left unwashed (NW group), washed in Dulbecco's phosphate-buffered saline supplemented with 0.1% BSA (BSA group), and washed on a Percoll(®) gradient (PERCOLL group). After preparation of semen samples, changes in motility patterns were studied by CASA, calcium uptake by spectrofluorimetry, and ROS generation, spontaneous acrosome reaction, and lipid disorder by means of flow cytometry. Finally IVF assays were also performed with the different semen samples and penetrability results evaluated at 2 and 4 h post insemination (hpi). Independently of the sperm treatment, epididymal spermatozoa showed higher values of progressive motility, percentage of live cells with low lipid disorder, and penetration ability at 4 hpi than the corresponding ejaculated spermatozoa. Ejaculated spermatozoa showed higher levels of calcium uptake, ROS generation and percentage of spontaneous acrosome reaction than epididymal sperm. Regarding sperm treatments, PERCOLL group showed the highest values for some motility parameters (linearity of the curvilinear trajectory, straightness, and average path velocity/curvilinear velocity), ROS generation and penetration ability at 2 and 4 hpi; however this same group showed the lowest values for sperm curvilinear velocity and lateral head displacement. From all experimental groups, ejaculated-PERCOLL-treated spermatozoa showed the highest fertilization ability after 2 hpi. Results suggest that capacitation pathways can be regulated by suitable treatments making the ejaculated sperm able to reach capacitation and fertilize oocytes in similar levels than epididymal spermatozoa, although most of the studied capacitation-associated changes do not correlate with this ability. PMID:20688369

  4. A new approach to optimizing urea clearances in hemodialysis and continuous ambulatory peritoneal dialysis.

    Science.gov (United States)

    Nolph, K D; Keshaviah, P; Emerson, P; Van Stone, J C; Twardowski, Z J; Khanna, R; Moore, H L; Collins, A; Edward, A

    1995-01-01

    Recent studies suggest that the relationship of the net normalized protein catabolic rate (which is the normalized protein equivalent of nitrogen appearance [nPNA]) to the weekly clearance of urea normalized to total body water (Kt/V urea) in patients on continuous ambulatory peritoneal dialysis (CAPD) is curvilinear, rather than linear, as has been thought. The authors have reexamined the relationship of nPNA to weekly Kt/V urea in a CAPD population by cross-sectional analysis to see if the curvilinear definition of the relationship is as good as or better than the usual linear description. They also examined this relationship in the hemodialysis populations at the Dialysis Clinics Inc. in Columbia, Missouri, and in the Renal Kidney Disease Program in Minneapolis, Minnesota. It seems obvious that there should be a plateau of nPNA in each therapy because extension of linear regressions would predict protein intakes of normal individuals exceeding 8 g/kg/body weight/day. The authors compared their findings to other published results. Intuitively and analytically, the curvilinear relationships seem likely. The authors observed that the nPNA plateau is achieved at lower Kt/V in patients on CAPD than in those on hemodialysis, which is compatible with the peak concentration hypothesis. Asymptotes for CAPD and hemodialysis are similar. Weekly Kt/V urea requirements to achieve nPNA values at 95% of the asymptote are greater than those usually delivered. However, such nearly complete elimination of uremic appetite suppression may not be practical or necessary for achieving acceptable nutritional status and long-term survival in most patients. Optimum therapy may be well above adequate therapy relative to minimizing appetite suppression by uremia. PMID:8573843

  5. Steeply dipping heaving bedrock, Colorado: Part 1 - Heave features and physical geological framework

    Science.gov (United States)

    Noe, D.C.; Higgins, J.D.; Olsen, H.W.

    2007-01-01

    Differentially heaving bedrock has caused severe damage near the Denver metropolitan area. This paper describes heave-feature morphologies, the underlying bedrock framework, and their inter-relationship. The heave features are linear to curvilinear and may attain heights of 0.7 m (2.4 ft), widths of 58 m (190 ft), and lengths of 1,067 m (3,500 ft). They are nearly symmetrical to highly asymmetrical in cross section, with width-to-height ratios of 45:1 to 400:1, and most are oriented parallel with the mountain front. The bedrock consists of Mesozoic sedimentary formations having dip angles of 30 degrees to vertical to overturned. Mixed claystone-siltstone bedding sequences up to 36-m (118-ft) thick are common in the heave-prone areas, and interbeds of bentonite, limestone, or sandstone may be present. Highly fractured zones of weathered to variably weathered claystone extend to depths of 19.5 to 22.3 m (64 to 73 ft). Fracture spacings are 0.1 to 0.2 m (0.3 to 0.7 ft) in the weathered and variably weathered bedrock and up to 0.75 m (2.5 ft) in the underlying, unweathered bedrock. Curvilinear shear planes in the weathered claystone show thrust or reverse offsets up to 1.2 m (3.9 ft). Three associations between heave-feature morphologies and the geological framework are recognized: (1) Linear, symmetrical to asymmetrical heaves are associated with primary bedding composition changes. (2) Linear, highly asymmetrical heaves are associated with shear planes along bedding. (3) Curvi-linear, highly asymmetrical heaves are associated with bedding-oblique shear planes.

  6. Intrinsic and extrinsic motivational orientations in the competitive context: an examination of person-situation interactions.

    Science.gov (United States)

    Abuhamdeh, Sami; Csikszentmihalyi, Mihaly

    2009-10-01

    The current study examined Intrinsic Motivation Orientation and Extrinsic Motivation Orientation (Work Preference Inventory; Amabile, Hill, Hennessey, & Tighe, 1994) as potential trait-level moderators of the way Internet chess players responded to the intrinsic and extrinsic rewards of the chess games they played. On the basis of the defining characteristics of these 2 types of motivational orientations, we predicted that (a) Intrinsic Motivation Orientation would be associated with a stronger curvilinear relationship between challenge and enjoyment and (b) Extrinsic Motivation Orientation would be associated with a heightened affective responsivity to competitive outcome (i.e., winning vs. losing). Results supported the predictions. Implications of the findings are discussed. PMID:19678872

  7. Covariance matrices and applications to the field of nuclear data

    International Nuclear Information System (INIS)

    A student's introduction to covariance error analysis and least-squares evaluation of data is provided. It is shown that the basic formulas used in error propagation can be derived from a consideration of the geometry of curvilinear coordinates. Procedures for deriving covariances for scaler and vector functions of several variables are presented. Proper methods for reporting experimental errors and for deriving covariance matrices from these errors are indicated. The generalized least-squares method for evaluating experimental data is described. Finally, the use of least-squares techniques in data fitting applications is discussed. Specific examples of the various procedures are presented to clarify the concepts

  8. Moral development and perceptual role-taking egocentrism: their development and interrelationship across the life-span.

    Science.gov (United States)

    Del Vento Bielby, D; Papalia, D E

    1975-01-01

    Moral judgments and perceptual role taking egocentrism were assessed in seventy-two middle-class people whose age range encompassed a significant portion of the life span. Findings support the anticipated curvilinear relationship between moral development and age, and egocentrism and age. However, the close conceptual development and age, and egocentrism and age. However, the close conceptual relationship between moral development and egocentrism throughout life received only slight statistical support, which attained significance only in the fifteen- to nineteen-year-old age group. The existence of "self-involving" egocentrism was postulated to be an important determinant or moral development during adulthood. PMID:1221055

  9. Application of the Richards function to the description of leaf area growth in maize (Zea mays L.)

    OpenAIRE

    Andrzej Grzegorczyk

    2014-01-01

    The leaf area growth in maize was approximated basing on the Richards function in the form of: y=A[l+b exp(-kt)]1/(1-m) . The constant coefficients of the Richards function were found by means of the Marquardt's method. The initial values of parameters were given basing on results of the preliminary approximation of the growth process by means of logistic function y = A[l+b exp(-kt)]-1. The procedure of nonlinear regression was found to be useful (curvilinear determination coefficient R2 = 0....

  10. Industry Relatedness and Post-Acquisition Innovative Performance

    DEFF Research Database (Denmark)

    Cefis, Elena; Marsili, Orietta; Rigamonti, Damiana

    2015-01-01

    This paper examines how characteristics of acquiring and acquired firms influence the curvilinear (inverted U-shaped) relationship between relatedness and post-acquisition innovative performance. Using a relatedness index based on industry co-occurrence in a sample of 1,736 Dutch acquisitions, we...... find that acquirer's internal R&D and acquisition experience, and the small size of acquired firms, help to reach a balance between exploration of novelty and exploitation of synergies in unrelated acquisitions, and to achieve higher post-acquisition performance. However, while the acquirer's R...

  11. Comparable stocks, boundedly rational stock markets and IPO entry rates.

    Directory of Open Access Journals (Sweden)

    Jay Chok

    Full Text Available In this study, we examine how initial public offerings (IPO entry rates are affected when stock markets are boundedly rational and IPO firms infer information from their counterparts in the market. We hypothesize a curvilinear relationship between the number of comparable stocks and initial public offerings (IPO entry rates into the NASDAQ Stock Exchange. Furthermore, we argue that trading volume and changes in stock returns partially mediates the relationship between the number of comparable stocks and IPO entry rates. The statistical evidence provides strong support for the hypotheses.

  12. Self organized locomotion via polyhedral geometry: a minimal example

    CERN Document Server

    Ghosh, Shankar; Bhattacharya, S; Nitsure, Nitin

    2016-01-01

    In this paper we establish a geometrical route to self-organisation. We show that the relevant underlying geometry of the configuration space is a curvilinear polyhedral region. The energetics over the polyhedral region localizes the available space within the close proximity of a corner of this polyhedra. This results into a stronger entrapment of the state which provides it the observed geometrical shape, functionality, and maintains its stability. These theoretical considerations are borne out in the experiments where we study the case of an uphill locomotion of a self organised dumbbell pair placed in a rotating cylinder.

  13. Eddy currents in the vacuum vessel of the ETE spherical tokamak

    Science.gov (United States)

    Ludwig, G. O.; DelBosco, E.; Ferreira, J. G.

    2005-07-01

    A Green's function method is developed to evaluate the currents induced during startup in the vacuum vessel of ETE (Experimento Tokamak Esférico). The non-homogeneous integral equation for the axisymmetric eddy currents distribution is determined using a thin shell approximation for the vacuum vessel and local curvilinear coordinates. This problem is reduced to a circuit model by adopting spectral representations both for the centreline of the vacuum vessel and the surface current density. Results of this model are compared with the distribution of eddy currents measured in ETE.

  14. BOUSSINESQ MODELLING OF NEARSHORE WAVES UNDER BODY FITTED COORDINATE

    Institute of Scientific and Technical Information of China (English)

    FANG Ke-zhao; ZOU Zhi-li; LIU Zhong-bo; YIN Ji-wei

    2012-01-01

    A set of nonlinear Boussinesq equations with fully nonlinearity property is solved numerically in generalized coordinates,to develop a Boussinesq-type wave model in dealing with irregular computation boundaries in complex nearshore regions and to facilitate the grid refinements in simulations.The governing equations expressed in contravariant components of velocity vectors under curv ilinear coordinates are derived and a high order finite difference scheme on a staggered grid is employed for the numerical implementation.The developed model is used to simulate nearshore wave propagations under curvilinear coordinates,the numerical results are compared against analytical or experimental data with a good agreement.

  15. MEMS-Based Spinning Nozzle

    Science.gov (United States)

    Okojie, Robert S. (Inventor)

    2003-01-01

    A nozzle body and assembly for delivering atomized fuel to a combustion chamber. The nozzle body is rotatably mounted onto a substrate. One or more curvilinear fuel delivery channels are in flow communication with an internal fuel distribution cavity formed in the nozzle body. Passage of pressurized fuel through the nozzle body causes the nozzle body to rotate. Components of the nozzle assembly are formed of silicon carbide having surfaces etched by deep reactive ion etching utilizing MEMS (micro-electro-mechanical systems) technology. A fuel premix chamber is carried on the substrate in flow communication with a supply passage in the nozzle body.

  16. 等参谱元方法的研究%RESEARCH OF AN ISOPARAMETRIC SPECTRAL ELEMENT METHOD

    Institute of Scientific and Technical Information of China (English)

    陈雪江; 秦国良; 徐忠

    2003-01-01

    An isoparametric spectral element method that combines the idea of the isopara-metric element in finite element methods with spectral element methods is pro-posed. The computational domain is broken up into curvilinear quadrangular ele-ments to approach boundaries more specifically and solve the differential equation in complex geometry. By this means both the Helmholtz equations with rect-angular geometry and the Poisson's equations with annular geometry those have analytical solutions are solved. The predicted results are in excellent agreement with the analytical solutions.

  17. Children of divorce in the 1990s: an update of the Amato and Keith (1991) meta-analysis.

    Science.gov (United States)

    Amato, P R

    2001-09-01

    The present study updates the P. R. Amato and B. Keith (1991) meta-analysis of children and divorce with a new analysis of 67 studies published in the 1990s. Compared with children with continuously married parents, children with divorced parents continued to score significantly lower on measures of academic achievement, conduct, psychological adjustment, self-concept, and social relations. After controlling for study characteristics, curvilinear trends with respect to decade of publication were present for academic achievement, psychological well-being, self-concept, and social relations. For these outcomes, the gap between children with divorced and married parents decreased during the 1980s and increased again during the 1990s.

  18. Geometrical rectification of spin-scan images from Pioneer 11

    Science.gov (United States)

    Strickland, R. N.; Burke, J. J.

    1980-01-01

    Images of Saturn received from Pioneer 11 suffer from geometrical distortions due to the curvilinear scan lines and the unequal sampling intervals in orthogonal directions, which are inherent in spin-scan imaging. In this paper geometrical image rectification by polynomial transformation based on control points is discussed. Factors that affect the accuracy of reconstruction are shown to include the spatial distribution and spatial density of control points, and the order of the polynomial distortion model. A computer implementation of the technique is described.

  19. Image separation using wavelet-complex shearlet dictionary

    Institute of Scientific and Technical Information of China (English)

    Shuaiqi Liu; Shaohai Hu; Yang Xiao

    2014-01-01

    This paper presents a new method for image separation through employing a combined dictionary consisting of wavelets and complex shearlets. Because the combined dictionary sparsely represents points and curvilinear singularities respectively, the image can be decomposed into pointlike and curvelike parts as accurate as possible. The proposed method based on the geo-metric separation theory introduced by Donoho in 2005 shows that accurate geometric separation of the morphological y distinct fea-tures of points and curves can be achieved by l1 minimization. The experimental results show that the proposed method can not only be effective but also greatly reduce the computing time.

  20. Complex variable methods in elasticity

    CERN Document Server

    England, A H

    2003-01-01

    The plane strain and generalized plane stress boundary value problems of linear elasticity are the focus of this graduate-level text, which formulates and solves these problems by employing complex variable theory. The text presents detailed descriptions of the three basic methods that rely on series representation, Cauchy integral representation, and the solution via continuation. Its five-part treatment covers functions of a complex variable, the basic equations of two-dimensional elasticity, plane and half-plane problems, regions with circular boundaries, and regions with curvilinear bounda

  1. On symmetric and upwind TVD schemes

    Science.gov (United States)

    Yee, H. C.

    1986-01-01

    The performance of the upwind and symmetric total variation diminishing (TVD) schemes in viscous and inviscid airfoil steady-state calculations is considered, and the extension of the implicit second-order-accurate TVD scheme for hyperbolic systems of conservative laws in curvilinear coordinates is discussed. For two-dimensional steady-state applications, schemes are implemented in a conservative noniterative alternating direction implicit form, and results illustrate that the algorithm produces a fairly good solution for an RAE2822 airfoil calculation. The study demonstrates that the symmetric TVD scheme is as accurate as the upwind TVD scheme, while requiring less computational effort than it.

  2. A high-precision algorithm for axisymmetric flow

    Directory of Open Access Journals (Sweden)

    A. Gokhman

    1995-01-01

    Full Text Available We present a new algorithm for highly accurate computation of axisymmetric potential flow. The principal feature of the algorithm is the use of orthogonal curvilinear coordinates. These coordinates are used to write down the equations and to specify quadrilateral elements following the boundary. In particular, boundary conditions for the Stokes' stream-function are satisfied exactly. The velocity field is determined by differentiating the stream-function. We avoid the use of quadratures in the evaluation of Galerkin integrals, and instead use splining of the boundaries of elements to take the double integrals of the shape functions in closed form. This is very accurate and not time consuming.

  3. Tensor formulation of the model equations on strong conservation form for an incompressible flow in general coordinates

    DEFF Research Database (Denmark)

    Jørgensen, Bo Hoffmann

    2003-01-01

    equations on a general form which accommodate curvilinear coordinates. Strong conservation form is obtained by formulating the equations so that the flow variables, velocity and pressure, are expressed in thephysical coordinate system while the location of evaluation is expressed within the transformed...... coordinate system. The tensor formulation allows both a finite difference and a pseudo-spectral description of the model equations. The intention is for thefinite difference formulation to achieve the same robustness and conservation properties as a finite volume discretization. Furthermore, an invariant...

  4. Nonlinear radiative heat transfer and Hall effects on a viscous fluid in a semi-porous curved channel

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Z.; Naveed, M., E-mail: rana.m.naveed@gmail.com [Department of Mathematics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Sajid, M. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan)

    2015-10-15

    In this paper, effects of Hall currents and nonlinear radiative heat transfer in a viscous fluid passing through a semi-porous curved channel coiled in a circle of radius R are analyzed. A curvilinear coordinate system is used to develop the mathematical model of the considered problem in the form partial differential equations. Similarity solutions of the governing boundary value problems are obtained numerically using shooting method. The results are also validated with the well-known finite difference technique known as the Keller-Box method. The analysis of the involved pertinent parameters on the velocity and temperature distributions is presented through graphs and tables.

  5. Balancing the Trade-off Between Learning Prospects and Spillover Risks

    DEFF Research Database (Denmark)

    Perri, Alessandra; Andersson, Ulf; Nell, Phillip Christopher;

    2013-01-01

    This paper investigates local vertical linkages of foreign subsidiaries and the dual role of such linkages as conduits for learning as well as potential channels for spillovers to competitors. On the basis of data from 97 subsidiaries, we analyze the quality of such linkages under varying levels ...... find a curvilinear relationship between the extent of competitive pressure and the quality of local linkages confirming our argument of a trade-off between learning prospects and spillover risks. Furthermore, the level of subsidiary capabilities moderates this relationship....

  6. Pauli equation for a charged spin particle on a curved surface in an electric and magnetic field

    OpenAIRE

    Wang, Yong-long(Department of Physics, Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing University, 210093, Nanjing, China); Du, Long; Xu, Chang-Tan; Liu, Xiao-Jun; Zong, Hong-shi(Department of Physics, Nanjing University, Nanjing 210093, China)

    2014-01-01

    We derive the Pauli equation for a charged spin particle confined to move on a spatially curved surface $\\mathcal{S}$ in an electromagnetic field. Using the thin-layer quantization scheme to constrain the particle on $\\mathcal{S}$, and in the transformed spinor representations, we obtain the well-known geometric potential $V_g$ and the presence of $e^{-i\\varphi}$, which can generate additive spin connection geometric potentials by the curvilinear coordinate derivatives, and we find that the t...

  7. Finite volume methods for the incompressible Navier-Stokes equations on unstructured grids

    Energy Technology Data Exchange (ETDEWEB)

    Meese, Ernst Arne

    1998-07-01

    Most solution methods of computational fluid dynamics (CFD) use structured grids based on curvilinear coordinates for compliance with complex geometries. In a typical industry application, about 80% of the time used to produce the results is spent constructing computational grids. Recently the use of unstructured grids has been strongly advocated. For unstructured grids there are methods for generating them automatically on quite complex domains. This thesis focuses on the design of Navier-Stokes solvers that can cope with unstructured grids and ''low quality grids'', thus reducing the need for human intervention in the grid generation.

  8. High Order Filter Methods for the Non-ideal Compressible MHD Equations

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, Bjoern

    2003-01-01

    The generalization of a class of low-dissipative high order filter finite difference methods for long time wave propagation of shock/turbulence/combustion compressible viscous gas dynamic flows to compressible MHD equations for structured curvilinear grids has been achieved. The new scheme is shown to provide a natural and efficient way for the minimization of the divergence of the magnetic field numerical error. Standard divergence cleaning is not required by the present filter approach. For certain non-ideal MHD test cases, divergence free preservation of the magnetic fields has been achieved.

  9. Immersed-boundary methods for general finite-difference and finite-volume Navier-Stokes solvers

    OpenAIRE

    A. Pinelli; Naqavi, I. Z.; Piomelli, U.; Favier, J.

    2010-01-01

    International audience We present an immersed-boundary algorithm for incompressible flows with complex boundaries, suitable for Cartesian or curvilinear grid system. The key stages of any immersed-boundary technique are the interpolation of a velocity field given on a mesh onto a general boundary (a line in 2D, a surface in 3D), and the spreading of a force field from the immersed boundary to the neighboring mesh points, to enforce the desired boundary conditions on the immersed-boundary p...

  10. Nonlinear radiative heat transfer and Hall effects on a viscous fluid in a semi-porous curved channel

    Directory of Open Access Journals (Sweden)

    Z. Abbas

    2015-10-01

    Full Text Available In this paper, effects of Hall currents and nonlinear radiative heat transfer in a viscous fluid passing through a semi-porous curved channel coiled in a circle of radius R are analyzed. A curvilinear coordinate system is used to develop the mathematical model of the considered problem in the form partial differential equations. Similarity solutions of the governing boundary value problems are obtained numerically using shooting method. The results are also validated with the well-known finite difference technique known as the Keller-Box method. The analysis of the involved pertinent parameters on the velocity and temperature distributions is presented through graphs and tables.

  11. Nonlinear radiative heat transfer and Hall effects on a viscous fluid in a semi-porous curved channel

    Science.gov (United States)

    Abbas, Z.; Naveed, M.; Sajid, M.

    2015-10-01

    In this paper, effects of Hall currents and nonlinear radiative heat transfer in a viscous fluid passing through a semi-porous curved channel coiled in a circle of radius R are analyzed. A curvilinear coordinate system is used to develop the mathematical model of the considered problem in the form partial differential equations. Similarity solutions of the governing boundary value problems are obtained numerically using shooting method. The results are also validated with the well-known finite difference technique known as the Keller-Box method. The analysis of the involved pertinent parameters on the velocity and temperature distributions is presented through graphs and tables.

  12. Mercury in shark in western Australia: a preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, D.A.; Edmonds, J.S.; Edinger, J.J.

    1977-01-01

    Linear and curvilinear regressions relating mercury concentration and size were used in conjunction with catch data to estimate the average concentration in the three major shark species in the Western Australia fishery industry. The three species were whiskery (Furgaleus ventralis), bronze whaler (Carcharhinus obscurus) and gummy (Emissola antarctica) sharks. The averge mercury concentration for the 3 species was found to be approximately 0.75 ppM. The relevance of this to Public Health regulations was discussed and the need for information on consumption of shark stressed.

  13. An Extension of the Athena++ Code Framework for GRMHD Based on Advanced Riemann Solvers and Staggered-mesh Constrained Transport

    Science.gov (United States)

    White, Christopher J.; Stone, James M.; Gammie, Charles F.

    2016-08-01

    We present a new general relativistic magnetohydrodynamics (GRMHD) code integrated into the Athena++ framework. Improving upon the techniques used in most GRMHD codes, ours allows the use of advanced, less diffusive Riemann solvers, in particular HLLC and HLLD. We also employ a staggered-mesh constrained transport algorithm suited for curvilinear coordinate systems in order to maintain the divergence-free constraint of the magnetic field. Our code is designed to work with arbitrary stationary spacetimes in one, two, or three dimensions, and we demonstrate its reliability through a number of tests. We also report on its promising performance and scalability.

  14. Fucosidosis: MRI and MRS findings

    International Nuclear Information System (INIS)

    Fucosidosis is a rare, autosomal recessive lysosomal storage disease in which fucose-containing glycolipids, glycoproteins, and oligosaccharides accumulate in tissues as a consequence of α-l-fucosidase enzyme deficiency. We present the MR imaging findings of diffuse white-matter hyperintensity and pallidal curvilinear streak hyperintensity in a 6-year-old Caucasian girl with a diagnosis of fucosidosis based on cDNA isolated from skin fibroblasts. This report also includes the MRS findings of a decreased N-acetylaspartate/choline ratio together with an abnormal peak at 3.8 ppm which expand the knowledge of the neuroradiological spectrum of this rare disease. (orig.)

  15. Late-Onset Capsular Block Syndrome: Unusually Delayed Presentation

    Directory of Open Access Journals (Sweden)

    Mrinal Rana

    2013-12-01

    Full Text Available Capsular block syndrome (CBS has been known to occur as a rare complication of cataract surgery with continuous curvilinear capsulorhexis and a posterior-chamber lens implant. Typically, it presents with reduced vision in the early postoperative period and is characterised by a forward displacement of the posterior-chamber intra-ocular lens and an accumulation of intra-capsular opaque material. Management of CBS is usually by Nd:YAG laser capsulotomy. In this report, we describe a unique case of very-delayed-onset CBS with good visual acuity, occurring 8 years after surgery. It was treated successfully with surgical removal of the opaque material.

  16. Fish stocking density impacts tank hydrodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Michael R.; Lunger, Angela; Laursen, Jesper;

    2006-01-01

    The effect of stocking density upon the hydrodynamics of a circular tank, configured in a recirculation system, was investigated. Red drums Sciaenops ocellatus of approximately 140 g wet weight, were stocked at five rates varying from 0 to 12 kg m-3. The impact of the presence of fish upon tank...... hydrodynamics was established using in-tank-based Rhodamine WT fluorometry at a flow rate of 0.23 l s-1 (tank exchange rate of 1.9 h-1). With increasing numbers of animals, curvilinear relationships were observed for dispersion coefficients and tank mixing times. Stocking densities of 3, 6, 9 and 12 kg m-3...

  17. Roasting green coffee beans using spouted bed roaster: changes in physical characteristics

    OpenAIRE

    Nagaraju, V. D.; Bhattacharya, Suvendu

    2010-01-01

    Pea-berry grade of green coffee (Coffea arabica) beans were roasted in a laboratory model spouted bed roaster at different temperatures (150–250°C) and times (30–300 s). The roasted samples were analysed for instrumental colour (hue, chroma and brightness) and texture. Brightness of the roasted samples varied between 5.2 and 20.4%, and time of roasting markedly decreased the brightness values. The chroma showed a curvilinear decrease with both time and temperature of roasting; the lowest valu...

  18. Flow structure interaction around an axial-flow hydrokinetic turbine: Experiments and CFD simulations

    Science.gov (United States)

    Kang, S.; Chamorro, L.; Hill, C.; Arndt, R.; Sotiropoulos, F.

    2014-12-01

    We carry out large-eddy simulation of turbulent flow past a complete hydrokinetic turbine mounted on the bed of a straight rectangular open channel. The complex turbine geometry, including the rotor and all stationary components, is handled by employing the curvilinear immersed boundary (CURVIB) method [1], and velocity boundary conditions near all solid surfaces are reconstructed using a wall model based on solving the simplified boundary layer equations [2]. In this study we attempt to directly resolve flow-blade interactions without introducing turbine parameterization methods. The computed wake profiles of velocities and turbulent stresses agree well with the experimentally measured values.

  19. The differential roentgen diagnosis of the pelvic extraperitoneal effusion and the pelvic intraperitoneal effusion

    International Nuclear Information System (INIS)

    The plain film signs of a perivesical extraperitoneal effusion included displacement of the bladder, loss of normal pelvic soft tissure shadows, and upward-displacement of the peritoneum and pelvic ileal loops out of the pelvis. The roentgen appearances of the intraperitoneal pelvic effusion, were the radiographically discernible curvilinear lucent stripe representing the areolar tissure between the dome of the bladder and the pelvic peritoneum, the normally situated peritoneum, and the homogeneous density between the peritoneum and the displaced loops of bowel, referred to as the ''dog-ear'' sign by MeCort. (author)

  20. Preferential access to emotion under attentional blink: evidence for threshold phenomenon

    Directory of Open Access Journals (Sweden)

    Szczepanowski Remigiusz

    2015-03-01

    Full Text Available The present study provides evidence that the activation strength produced by emotional stimuli must pass a threshold level in order to be consciously perceived, contrary to the assumption of continuous quality of representation. An analysis of receiver operating characteristics (ROC for attentional blink performance was used to distinguish between two (continuous vs. threshold models of emotion perception by inspecting two different ROC’s shapes. Across all conditions, the results showed that performance in the attentional blink task was better described by the two-limbs ROC predicted by the Krantz threshold model than by the curvilinear ROC implied by the signal-detection theory.

  1. The discrete ordinate method in association with the finite-volume method in non-structured mesh; Methode des ordonnees discretes associee a la methode des volumes finis en maillage non structure

    Energy Technology Data Exchange (ETDEWEB)

    Le Dez, V.; Lallemand, M. [Ecole Nationale Superieure de Mecanique et d`Aerotechnique (ENSMA), 86 - Poitiers (France); Sakami, M.; Charette, A. [Quebec Univ., Chicoutimi, PQ (Canada). Dept. des Sciences Appliquees

    1996-12-31

    The description of an efficient method of radiant heat transfer field determination in a grey semi-transparent environment included in a 2-D polygonal cavity with surface boundaries that reflect the radiation in a purely diffusive manner is proposed, at the equilibrium and in radiation-conduction coupling situation. The technique uses simultaneously the finite-volume method in non-structured triangular mesh, the discrete ordinate method and the ray shooting method. The main mathematical developments and comparative results with the discrete ordinate method in orthogonal curvilinear coordinates are included. (J.S.) 10 refs.

  2. GRID GENERATION AND NUMERICAL SIMULATION OF 2-D RIVER FLOW GRID GENERATION AND NUMERICAL SIMULATION OF 2-D RIVER FLOW

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents new weighting functions in grid generation and new discretizing scheme of momentum equations in numerical simulation of river flow. By using the new weighting functions, the curvilinear grid could be concentrated as desired near the assigned points or lines in physical plane. By using the new discretizing scheme, the difficulties caused by movable boundary and dry riverbed can be overcome. As an application, the flow in the Wuhan Section of Yangtze River is simulated. The computational results are in good agreement with the measured results. The new method is applicable to the numerical simulation of 2-D river flow with irregular region and moveable boundary.

  3. Solution of volume-surface integral equations using higher-order hierarchical Legendre basis functions

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Meincke, Peter; Breinbjerg, Olav;

    2007-01-01

    applied to transform the VSIE into a system of linear equations. The higher-order MoM provides significant reduction in the number of unknowns in comparison with standard MoM formulations using low-order basis functions, such as RWG functions. Due to the orthogonal nature of the higher-order Legendre......The problem of electromagnetic scattering by composite metallic and dielectric objects is solved using the coupled volume-surface integral equation (VSIE). The method of moments (MoM) based on higher-order hierarchical Legendre basis functions and higher-order curvilinear geometrical elements is...

  4. Flow and sediment transport across oblique channels

    DEFF Research Database (Denmark)

    Hjelmager Jensen, Jacob; Madsen, Erik Østergaard; Fredsøe, Jørgen

    1998-01-01

    A 3D numerical investigation of flow across channels aligned obliquely to the main flow direction has been conducted. The applied numerical model solves the Reynolds-averaged Navier-Stokes equations using the k-ε model for turbulence closure on a curvilinear grid. Three momentum equations...... are solved, but the computational domain is 2D due to a uniformity along the channel alignment. Two important flow features arise when the flow crosses the channel: (i) the flow will be refracted in the direction of the channel alignment. This may be described by a depth-averaged model. (ii) due to shear...

  5. Hypermass generalization of Einstein's gravitation theory

    Science.gov (United States)

    Edmonds, J. D., Jr.

    1973-01-01

    The curvilinear invariant quaternion formalism is examined for curved space time. Einstein's gravitation equation is shown to have a simple and natural form in this notation. The hypermass generalization of particle mass, which was generated in our studies of the Dirac equation, is incorporated in gravitation by generalizing Einstein's equation. Covariance requires that the gravitational constant be generalized to an invariant quaternion when the mass is. The modification appears minor and of no importance cosmologically, unless one begins considering time and mass dependence of G.

  6. Reynolds and froude number effect on the flow past an interface-piercing circular cylinder

    OpenAIRE

    Koo Bonguk; Yang Jianming; Yeon Seong Mo; Stern Frederick

    2014-01-01

    The two-phase turbulent flow past an interface-piercing circular cylinder is studied using a high-fidelity orthogonal curvilinear grid solver with a Lagrangian dynamic subgrid-scale model for large-eddy simulation and a coupled level set and volume of fluid method for air-water interface tracking. The simulations cover the sub-critical and critical and post critical regimes of the Reynolds and sub and super-critical Froude numbers in order to investigate the effect of both dimensionless param...

  7. Studies of stability of blade cascade suction surface boundary layer

    Institute of Scientific and Technical Information of China (English)

    DONG Xue-zhi; YAN Pei-gang; HAN Wan-jin

    2007-01-01

    Compressible boundary layers stability on blade cascade suction surface was discussed by wind tunnel experiment and numerical solution. Three dimensional disturbance wave Parabolized Stability Equations(PSE) of orthogonal Curvilinear Coordinates in compressible flow was deducted. The surface pressure of blade in wind tunnel experiment was measured. The Falkner-Skan equation was solved under the boundary conditions of experiment result, and velocity, pressure and temperature of average flow were obtained. Substituted this result for discretization of the PSE Eigenvalue Problem, the stability problem can be solved.

  8. Fucosidosis: MRI and MRS findings

    Energy Technology Data Exchange (ETDEWEB)

    Oner, Ali Y.; Akpek, Sergin [Gazi University School of Medicine, Department of Radiology, Ankara (Turkey); Cansu, Ali; Serdaroglu, Ayse [Gazi University School of Medicine, Department of Paediatrics, Ankara (Turkey)

    2007-10-15

    Fucosidosis is a rare, autosomal recessive lysosomal storage disease in which fucose-containing glycolipids, glycoproteins, and oligosaccharides accumulate in tissues as a consequence of {alpha}-l-fucosidase enzyme deficiency. We present the MR imaging findings of diffuse white-matter hyperintensity and pallidal curvilinear streak hyperintensity in a 6-year-old Caucasian girl with a diagnosis of fucosidosis based on cDNA isolated from skin fibroblasts. This report also includes the MRS findings of a decreased N-acetylaspartate/choline ratio together with an abnormal peak at 3.8 ppm which expand the knowledge of the neuroradiological spectrum of this rare disease. (orig.)

  9. Application of damage mechanics in percussive drilling modelling

    OpenAIRE

    Mikhailov, SE; Namestnikova, IV

    2005-01-01

    A stationary-periodic quasi-static model of rock percussive deep drilling is introduced. First, an auxiliary problem of stationary indentation of a rigid indentor is considered. The rock is modelled by an in¯nite elastic medium with damage-induced material softening. The stationarity of the problem allows to reduce the damage history in a material point to the damage distribution down in space. The bore-hole is a semi-in¯nite cylinder with a curvilinear bottom. It is assumed the i...

  10. Symbolic computer vector analysis

    Science.gov (United States)

    Stoutemyer, D. R.

    1977-01-01

    A MACSYMA program is described which performs symbolic vector algebra and vector calculus. The program can combine and simplify symbolic expressions including dot products and cross products, together with the gradient, divergence, curl, and Laplacian operators. The distribution of these operators over sums or products is under user control, as are various other expansions, including expansion into components in any specific orthogonal coordinate system. There is also a capability for deriving the scalar or vector potential of a vector field. Examples include derivation of the partial differential equations describing fluid flow and magnetohydrodynamics, for 12 different classic orthogonal curvilinear coordinate systems.

  11. Impact of light intensity on flowering time and plant quality of Antirrhinum majus L.cultivar Chimes White

    Institute of Scientific and Technical Information of China (English)

    MUNIR Muhammad; JAMIL Muhammad; BALOCH Jalal-ud-din; KHATTAK Khalid Rehman

    2004-01-01

    Shades of different light intensities (29%, 43%, 54%, 60% or 68%) along with control (no shade) were studied to observe their effects on the flowering time and plant quality. A hyperbolic relationship was observed between different light intensities under shade, and time to flowering. The total number of flower buds showed a curvilinear relationship with light intensities. Growth parameters related to the plant characteristics such as plant height, leaf area and plant fresh weight were improved under shading treatments at the expense of flowering time and number of flower buds. However, both linear and polynomial models applied assumed that cultivar Chimes White was equally sensitive to light intensity throughout development.

  12. Real-time FPGA architectures for space-time frequency-planar MDSP

    Science.gov (United States)

    Madanayake, Arjuna

    In recent times, a variety of applications have emerged for real-time VLSI multidimensional digital filters, of which many draw upon broadband plane-wave filtering for array-based beam-forming and the processing of image sequences in video signals. This thesis describes recent progress with real-time hardware architectures for spatio-temporal multidimensional digital filters. The frequency-planar filter is a fundamental building block for many useful multidimensional digital filters including linear trajectory filters and plane-wave filters having beam, fan and cone shaped passbands. The proposed architectures for implementing the abovementioned frequency-planar building blocks can be broadly classified as systolic-array architectures and raster scanned architectures. The systolic-array architectures employ massively-parallel structures for very high throughput signal processing, with typical applications in RF beam-forming for wireless communications, microwave imaging, radar, radio astronomy, and navigation. The scanned-array structures have very low circuit complexity compared to systolic-arrays. However, the real-time throughput levels are correspondingly lower, and therefore, these architectures are most suited for slower applications such as ultrasonic imaging, digital video, sonar, and directional audio. A novel multidimensional look-ahead based speed optimization method is proposed for increasing the real-time computational throughput of the architectures. Furthermore, the 2D/3D frequency-planar filters, which conventionally require sampled linear and rectangular sensor arrays, have been extended to curvilinear coordinate systems using circular and toroidal sensor arrays, leading to applications such as the highly-selective directional enhancement of concentric broadband spiral-waves and the directional enhancement of linear flows on the surface of a torus. Prototype FPGA circuit implementations are provided for the proposed systolic-array processors

  13. Printing microstructures in a polymer matrix using a ferrofluid droplet

    Science.gov (United States)

    Abdel Fattah, Abdel Rahman; Ghosh, Suvojit; Puri, Ishwar K.

    2016-03-01

    We print complex curvilinear microstructures in an elastomer matrix using a ferrofluid droplet as the print head. A magnetic field moves the droplet along a prescribed path in liquid polydimethylsiloxane (PDMS). The droplet sheds magnetic nanoparticle (MNP) clusters in its wake, forming printed features. The PDMS is subsequently heated so that it crosslinks, which preserves the printed features in the elastomer matrix. The competition between magnetic and drag forces experienced by the ferrofluid droplet and its trailing MNPs highlight design criteria for successful printing, which are experimentally confirmed. The method promises new applications, such as flexible 3D circuitry.

  14. SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the verification of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.

  15. Alternating-direction implicit numerical solution of the time-dependent, three-dimensional, single fluid, resistive magnetohydrodynamic equations

    Energy Technology Data Exchange (ETDEWEB)

    Finan, C.H. III

    1980-12-01

    Resistive magnetohydrodynamics (MHD) is described by a set of eight coupled, nonlinear, three-dimensional, time-dependent, partial differential equations. A computer code, IMP (Implicit MHD Program), has been developed to solve these equations numerically by the method of finite differences on an Eulerian mesh. In this model, the equations are expressed in orthogonal curvilinear coordinates, making the code applicable to a variety of coordinate systems. The Douglas-Gunn algorithm for Alternating-Direction Implicit (ADI) temporal advancement is used to avoid the limitations in timestep size imposed by explicit methods. The equations are solved simultaneously to avoid syncronization errors.

  16. Asymptotic curved interface models in piezoelectric composites

    Science.gov (United States)

    Serpilli, Michele

    2016-10-01

    We study the electromechanical behavior of a thin interphase, constituted by a piezoelectric anisotropic shell-like thin layer, embedded between two generic three-dimensional piezoelectric bodies by means of the asymptotic analysis in a general curvilinear framework. After defining a small real dimensionless parameter ε, which will tend to zero, we characterize two different limit models and their associated limit problems, the so-called weak and strong piezoelectric curved interface models, respectively. Moreover, we identify the non-classical electromechanical transmission conditions at the interface between the two three-dimensional bodies.

  17. Two-point boundary value and Cauchy formulations in an axisymmetrical MHD equilibrium problem

    International Nuclear Information System (INIS)

    In this paper we present two equilibrium solvers for axisymmetrical toroidal configurations, both based on the expansion in poloidal angle method. The first one has been conceived as a two-point boundary value solver in a system of coordinates with straight field lines, while the second one uses a well-conditioned Cauchy formulation of the problem in a general curvilinear coordinate system. In order to check the capability of our moment methods to describe equilibrium accurately, a comparison of the moment solutions with analytical solutions obtained for a Solov'ev equilibrium has been performed. (author)

  18. Geometry for web microwave heating or drying to a desired profile in a waveguide

    Science.gov (United States)

    Habeger, Jr., Charles C.; Patterson, Timothy F.; Ahrens, Frederick W.

    2005-11-15

    A microwave heater and/or dryer has a nonlinear or curvilinear relative slot profile geometry. In one embodiment, the microwave dryer has at least one adjustable field modifier making it possible to change the geometry of the heater or dryer when drying different webs. In another embodiment, the microwave dryer provides more uniform drying of a web when the field modifier is adjusted in response to a sensed condition of the web. Finally, a method of microwave heating and/or drying a web achieves a uniform heating and/or drying profile.

  19. Assessment of Bone Mineral Density in Male Patients with Chronic Obstructive Pulmonary Disease by DXA and Quantitative Computed Tomography.

    Science.gov (United States)

    Fountoulis, George; Kerenidi, Theodora; Kokkinis, Constantinos; Georgoulias, Panagiotis; Thriskos, Paschal; Gourgoulianis, Konstantinos; Fezoulidis, Ioannis; Vassiou, Katerina; Vlychou, Marianna

    2016-01-01

    The purpose of this study is to identify the prevalence of osteoporosis in male patients with chronic obstructive pulmonary disease (COPD) by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) and to compare the diagnostic abilities of the above methods. Thirty-seven male patients with established COPD were examined with DXA and standard QCT in lumbar spine, including L1, L2, and L3 vertebrae. T-scores and bone mineral density values were calculated by DXA and QCT method, respectively. Comparative assessment of the findings was performed and statistical analysis was applied. QCT measurements found more COPD patients with impaired bone mineral density compared to DXA, namely, 13 (35.1%) versus 12 (32.4%) patients with osteopenia and 16 (43.2%) versus 9 (16.2%) patients with osteoporosis (p = 0.04). More vertebrae were found with osteoporosis by QCT compared to DXA (p = 0.03). The prevalence of osteoporosis among male patients with COPD is increased and DXA may underestimate this risk. QCT measurements have an improved discriminating ability to identify low BMD compared to DXA measurements because QCT is able to overcome diagnostic pitfalls including aortic calcifications and degenerative spinal osteophytes. PMID:27087809

  20. Radiology of posterior lumbar apophyseal ring fractures: Report of 13 cases

    Energy Technology Data Exchange (ETDEWEB)

    Dietemann, J.L.; Beaujeux, R.; Wackenheim, A.; Runge, M.; Bonneville, J.F.; Badoz, A.; Dosch, J.C.

    1988-08-01

    The authors report radiological findings in 13 cases of avulsion of the posterior lumbar apophyseal ring. The lesion affected young adults in 10 cases and adolescents in 3 cases. The lesion involved the inferior endplate of L4 in 11, and of L5 in 2 patients. 6 patients presented with unilateral sciatica, 3 with bilateral sciatica, and 4 with low back pain. Acute spinal trauma was evident only in 2 adolescents. Radiological recognition of the lesion was possible on plain films in 9 cases. CT demonstrates association of avulsion of the posterior vertebral apophyseal ring and herniated disc in all cases. Avulsion of the posterior apophyseal ring has to be differentiated from posterior longitudinal ligament, annulus, or herniated disc calcifications, as well as from posterior degenerative ridge osteophytes. Controversy about physiopathology of the lesion remains: Weakness of the apophyseal ring during childhood and in patients with Scheuermann's disease may explain avulsion of the apophyseal ring in association with median disc herniation.