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Sample records for targeted posterior slope

  1. 16 determination of posterior tibia slope and slope deterioration with ...

    African Journals Online (AJOL)

    Orth (SA), FCS (ECSA), Consultant Orthopaedic Surgeon, P.O. Box. 84074, Mombasa, Kenya. Email: michenimuthuuri@yahoo.com. ABSTRACT. Background: The posterior inclination of the tibia plateaux relative to the longitudinal axis of the tibia is referred to as the Posterior Tibia Slope (PTS). Fore knowledge of the mean ...

  2. The effect of posterior tibial slope on simulated laxity tests in cruciate-retaining TKA

    NARCIS (Netherlands)

    Marra, Marco A.; Strzelczak, Marta; Heesterbeek, Petra J.C.; van de Groes, Sebastiaan; Janssen, Dennis; Koopman, Bart F.J.M.; Wymenga, Ate B.; Verdonschot, Nico

    2017-01-01

    INTRODUCTION: Tibial slope can affect the outcomes of Total Knee Arthroplasty (TKA). More posterior slope potentially helps releasing a too tight flexion gap and it is generally associated with a wider range of post-operative knee flexion. However, the mechanism by which tibial slope affects the

  3. POSTERIOR TIBIAL SLOPE AS A RISK FACTOR FOR ANTERIOR CRUCIATE LIGAMENT RUPTURE IN SOCCER PLAYERS

    Directory of Open Access Journals (Sweden)

    Seçkin Şenışık

    2011-12-01

    Full Text Available Anterior cruciate ligament (ACL is the primary stabilizer of the knee. An impairment of any of the dynamic or static stability providing factors can lead to overload on the other factors and ultimately to deterioration of knee stability. This can result in anterior tibial translation and rupture of the ACL. The purpose of this study was to examine the influence of tibial slope on ACL injury risk on soccer players. A total of 64 elite soccer players and 45 sedentary controls were included in this longitudinal and controlled study. The angle between the tibial mid-diaphysis line and the line between the anterior and posterior edges of the medial tibial plateau was measured as the tibial slope via lateral radiographs. Individual player exposure, and injuries sustained by the participants were prospectively recorded. Eleven ACL injuries were documented during the study period. Tibial slope was not different between soccer players and sedentary controls. Tibial slope in the dominant and non-dominant legs was greater for the injured players compared to the uninjured players. The difference reached a significant level only for the dominant legs (p 0.05, a higher tibial slope was observed in dominant legs of injured players (p < 0.05. Higher tibial slope on injured soccer players compared to the uninjured ones supports the idea that the tibial slope degree might be an important risk factor for ACL injury.

  4. Biomechanical Effects of Posterior Condylar Offset and Posterior Tibial Slope on Quadriceps Force and Joint Contact Forces in Posterior-Stabilized Total Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Kyoung-Tak Kang

    2017-01-01

    Full Text Available This study aimed to determine the biomechanical effect of the posterior condylar offset (PCO and posterior tibial slope (PTS in posterior-stabilized (PS fixed-bearing total knee arthroplasty (TKA. We developed ±1, ±2, and ±3 mm PCO models in the posterior direction and −3°, 0°, 3°, and 6° PTS models using a previously validated FE model. The influence of changes in the PCO and PTS on the biomechanical effects under deep-knee-bend loading was investigated. The contact stress on the PE insert increased by 14% and decreased by 7% on average as the PCO increased and decreased, respectively, compared to the neutral position. In addition, the contact stress on post in PE insert increased by 18% on average as PTS increased from −3° to 6°. However, the contact stress on the patellar button decreased by 11% on average as PTS increased from −3° to 6° in all different PCO cases. The quadriceps force decreased by 14% as PTS increased from −3° to 6° in all PCO models. The same trend was found in patellar tendon force. Changes in PCO had adverse biomechanical effects whereas PTS increase had positive biomechanical effects. However, excessive PTS should be avoided to prevent knee instability and subsequent failure.

  5. Posterior Tibial Slope Angle Correlates With Peak Sagittal and Frontal Plane Knee Joint Loading During Robotic Simulations of Athletic Tasks

    Science.gov (United States)

    Bates, Nathaniel A.; Nesbitt, Rebecca J.; Shearn, Jason T.; Myer, Gregory D.; Hewett, Timothy E.

    2017-01-01

    Background Tibial slope angle is a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury. However, the mechanical role of varying tibial slopes during athletic tasks has yet to be clinically quantified. Purpose To examine the influence of posterior tibial slope on knee joint loading during controlled, in vitro simulation of the knee joint articulations during athletic tasks. Study Design Descriptive laboratory study. Methods A 6 degree of freedom robotic manipulator positionally maneuvered cadaveric knee joints from 12 unique specimens with varying tibial slopes (range, −7.7° to 7.7°) through drop vertical jump and sidestep cutting tasks that were derived from 3-dimensional in vivo motion recordings. Internal knee joint torques and forces were recorded throughout simulation and were linearly correlated with tibial slope. Results The mean (6SD) posterior tibial slope angle was 2.2° ± 4.3° in the lateral compartment and 2.3° ± 3.3° in the medial compartment. For simulated drop vertical jumps, lateral compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee adduction (r = 0.60–0.65), flexion (r = 0.64–0.66), lateral (r = 0.57–0.69), and external rotation torques (r = 0.47–0.72) as well as inverse correlations with peak abduction (r = −0.42 to −0.61) and internal rotation torques (r = −0.39 to −0.79). Only frontal plane torques were correlated during sidestep cutting simulations. For simulated drop vertical jumps, medial compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee flexion torque (r = 0.64–0.69) and lateral knee force (r = 0.55–0.74) as well as inverse correlations with peak external torque (r = −0.34 to 20.67) and medial knee force (r = −0.58 to −0.59). These moderate correlations were also present during simulated sidestep cutting. Conclusion The investigation supported the theory that increased posterior

  6. Studying the effect of medial open wedge high tibial osteotomy on the posterior slope of tibia among patients with Genu varum

    Directory of Open Access Journals (Sweden)

    Seyyed Raza Sharifzadeh

    2017-09-01

    Full Text Available Background A slight change in the posterior slope of tibia results in complications such as limited movement of knee joint and higher risks of Osteoarthritis. Aims The present research seeks to study levels of tibia’s posterior slope change and limited movement of knee joint and knee stability following medial open wedge osteotomy used to treat patients with genu varum. Methods The present research is a clinical trial conducted in the form of a before and after study on patients with genu varum resorting to Imam Reza (PBUH, Khanevade, and Fajr hospitals from 2009 to 2012. As many as 40 knees (32 patients were studied and the posterior slope of tibia before and after medial open wedge high tibial osteotomy was measured by someone totally unaware of the research using true lateral radiography. Movement limitation and stability of the knee was measured before and after the operation using scope of motion and Lachman and Drawer test. Paired sample test was used in this research and SPSS was used to analyse the data. Results The average posterior slope of tibia before the operation was 9.912, while this value changed to 11.625 after the operation signifying a significant increase. In terms of limited knee joint movement, 7 patients were diagnosed with grade 5 Extension LAG after operation, while the remaining 33 patients had a normal motion range (Extension LAG=0. Conclusion Medial open wedge osteotomy above tibia can help increase the posterior slope of tibia.

  7. Measurement and comparison of tibial posterior slope angle in different methods based on three-dimensional reconstruction.

    Science.gov (United States)

    Zhang, Yang; Wang, Jian; Xiao, Jun; Zhao, Liang; Li, Zhi-Han; Yan, Ge; Shi, Zhan-Jun

    2014-06-01

    The tibial posterior slope (PTS) is an important parameter for sagittal alignment which is associated with postoperative range of motion. However, the variations of different population subsets and different referential axes are still uncertain. In this study, 80 healthy people from South China were recruited and measured on three-dimensional reconstruction of CT, with application of three referential axes, the proximal tibial long axis, the anterior and posterior cortices. The averages and standard deviations of medial PTS (MPTS) in the three methods were 8.43±3.06, 11.45±2.82 and 6.31±3.24, separately. The results of lateral PTS (LPTS) were 7.56±2.51, 10.17±2.42 and 5.22±2.59. There was no significant difference between the male and the female, and the two sides of one body. The results of the three axes varied but correlated with each other significantly. Through comparison it was found that, MPTS/LPTS of people from South China were different from the published data of other countries. Although PTS change markedly according to the reference axis, they show significant correlations with each other, and may be used safely. There are differences associated with races, but not gender nor the two sides of the body. The results of the study provided references for the reconstruction of the knee PTS, if the differences of reference axes, races and genders were considered. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Integration of Target and Effector Information in Human Posterior Parietal Cortex for the Planning of Action

    NARCIS (Netherlands)

    Medendorp, W.P.; Goltz, H.C.; Crawford, J.D.; Vilis, T.

    2005-01-01

    Recently, using event-related functional MRI (fMRI), we located a bilateral region in the human posterior parietal cortex (retIPS) that topographically represents and updates targets for saccades and pointing movements in eye-centered coordinates. To generate movements, this spatial information must

  9. Sustained posterior contralateral activity indicates re-entrant target processing in visual change detection: An EEG study

    Directory of Open Access Journals (Sweden)

    Daniel eSchneider

    2014-05-01

    Full Text Available The present study investigated the neural mechanisms that contribute to the detection of visual feature changes between stimulus displays by means of event-related lateralizations of the electroencephalogram (EEG. Participants were instructed to respond to a luminance change in either of two lateralized stimuli that could randomly occur alone or together with an irrelevant orientation change of the same or contralateral stimulus. Task performance based on response times and accuracy was decreased compared to the remaining stimulus conditions when relevant and irrelevant feature changes were presented contralateral to each other (lateral distractor condition. The sensory response to the feature changes was reflected in a posterior contralateral positivity at around 100ms after change presentation and a posterior contralateral negativity in the N1 time window (N1pc. N2pc reflected a subsequent attentional bias in favor of the relevant luminance change. The continuation of the sustained posterior contralateral negativity (SPCN following N2pc covaried with response times within feature change conditions and revealed a posterior topography comparable to the earlier components associated with sensory and attentional mechanisms. Therefore, this component might reflect the re-processing of information based on sustained short-term memory representations in the visual system until a stable target percept is created that can serve as the perceptual basis for response selection and the initiation of goal-directed behavior.

  10. Changes in heparin dose response slope during cardiac surgery: possible result in inaccuracy in predicting heparin bolus dose requirement to achieve target ACT.

    Science.gov (United States)

    Ichikawa, Junko; Mori, Tetsu; Kodaka, Mitsuharu; Nishiyama, Keiko; Ozaki, Makoto; Komori, Makiko

    2017-09-01

    The substantial interpatient variability in heparin requirement has led to the use of a heparin dose response (HDR) technique. The accuracy of Hepcon-based heparin administration in achieving a target activated clotting time (ACT) using an HDR slope remains controversial. We prospectively studied 86 adult patients scheduled for cardiac surgery requiring cardiopulmonary bypass. The total dose of calculated heparin required for patient and pump priming was administered simultaneously to achieve a target ACT of 450 s for HDR on the Hepcon HMS system. Blood samples were obtained after the induction of anesthesia, at 3 min after heparin administration and after the initiation of CPB to measure kaolin ACT, HDR slope, whole-blood heparin concentration based on the HDR slope and anti-Xa heparin concentration, antithrombin and complete blood count. The target ACT of 450 s was not achieved in 68.6% of patients. Compared with patients who achieved the target ACT, those who failed to achieve their target ACT had a significantly higher platelet count at baseline. Correlation between the HDR slope and heparin sensitivity was poor. Projected heparin concentration and anti-Xa heparin concentration are not interchangeable based on the Bland-Altman analysis. It can be hypothesized that the wide discrepancy in HDR slope versus heparin sensitivity may be explained by an inaccurate prediction of the plasma heparin level and/or the change in HDR of individual patients, depending on in vivo factors such as extravascular sequestration of heparin, decreased intrinsic antithrombin activity level and platelet count and/or activity.

  11. Slippery Slopes

    Science.gov (United States)

    2004-01-01

    The wheel tracks in this image are an artifact of the difficult terrain faced recently by NASA's Mars Exploration Rover Opportunity deep inside 'Endurance Crater.' Opportunity took the picture with its navigation camera on the rover's 205th martian day, or sol (Aug. 21, 2004). On the preceding sol, to avoid a potentially hazardous rock target, the rover team changed routes. Steep slopes and lack of traction when driving in this terrain caused the rover to experience up to 50 percent slip during parts of its traverse. Opportunity ended up more than 50 centimeters (about 20 inches) downslope from the planned final position. Another shift in objective on sol 205 had Opportunity on the move again toward safer terrain. Analysis of the final drive showed the rover's traction increasing during its latest moves.

  12. Posterior Orbitofrontal and Anterior Cingulate Pathways to the Amygdala Target Inhibitory and Excitatory Systems with Opposite Functions.

    Science.gov (United States)

    Zikopoulos, Basilis; Höistad, Malin; John, Yohan; Barbas, Helen

    2017-05-17

    The bidirectional dialogue of the primate posterior orbitofrontal cortex (pOFC) with the amygdala is essential in cognitive-emotional functions. The pOFC also sends a uniquely one-way excitatory pathway to the amygdalar inhibitory intercalated masses (IM), which inhibit the medial part of the central amygdalar nucleus (CeM). Inhibition of IM has the opposite effect, allowing amygdalar activation of autonomic structures and emotional arousal. Using multiple labeling approaches to identify pathways and their postsynaptic sites in the amygdala in rhesus monkeys, we found that the anterior cingulate cortex innervated mostly the basolateral and CeM amygdalar nuclei, poised to activate CeM for autonomic arousal. By contrast, a pathway from pOFC to IM exceeded all other pathways to the amygdala by density and size and proportion of large and efficient terminals. Moreover, whereas pOFC terminals in IM innervated each of the three distinct classes of inhibitory neurons, most targeted neurons expressing dopamine- and cAMP-regulated phosphoprotein (DARPP-32+), known to be modulated by dopamine. The predominant pOFC innervation of DARPP-32+ neurons suggests activation of IM and inhibition of CeM, resulting in modulated autonomic function. By contrast, inhibition of DARPP-32 neurons in IM by high dopamine levels disinhibits CeM and triggers autonomic arousal. The findings provide a mechanism to help explain how a strong pOFC pathway, which is poised to moderate activity of CeM, through IM, can be undermined by the high level of dopamine during stress, resulting in collapse of potent inhibitory mechanisms in the amygdala and heightened autonomic drive, as seen in chronic anxiety disorders. SIGNIFICANCE STATEMENT The dialogue between prefrontal cortex and amygdala allows thoughts and emotions to influence actions. The posterior orbitofrontal cortex sends a powerful pathway that targets a special class of amygdalar intercalated mass (IM) inhibitory neurons, whose wiring may help

  13. Localization of nerve entry points as targets to block spasticity of the deep posterior compartment muscles of the leg.

    Science.gov (United States)

    Hu, Shuaiyu; Zhuo, Lifan; Zhang, Xiaoming; Yang, Shengbo

    2017-10-01

    To identify the optimal body surface puncture locations and the depths of nerve entry points (NEPs) in the deep posterior compartment muscles of the leg, 60 lower limbs of thirty adult cadavers were dissected in prone position. A curved line on the skin surface joining the lateral to the medial epicondyles of the femur was taken as a horizontal reference line (H). Another curved line joining the lateral epicondyle of the femur to the lateral malleolus was designated the longitudinal reference line (L). Following dissection, the NEPs were labeled with barium sulfate and then subjected to spiral computed tomography scanning. The projection point of the NEP on the posterior skin surface of the leg was designated P, and the projection in the opposite direction across the transverse plane was designated P'. The intersections of P on H and L were identified as P H and P L , and their positions and the depth of the NEP on PP' were measured using the Syngo system and expressed as percentages of H, L, and PP'. The P H points of the tibial posterior, flexor hallucis longus and flexor digitorum longus muscles were located at 38.10, 46.20, and 55.21% of H, respectively. The P L points were located at 25.35, 41.30, and 45.39% of L, respectively. The depths of the NEPs were 49.11, 54.64, and 55.95% of PP', respectively. The accurate location of these NEPs should improve the efficacy and efficiency of chemical neurolysis for treating spasticity of the deep posterior compartment muscles of the leg. Clin. Anat. 30:855-860, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Parasubthalamic and calbindin nuclei in the posterior lateral hypothalamus are the major hypothalamic targets for projections from the central and anterior basomedial nuclei of the amygdala.

    Science.gov (United States)

    Barbier, Marie; Chometton, Sandrine; Peterschmitt, Yvan; Fellmann, Dominique; Risold, Pierre-Yves

    2017-09-01

    The parasubthalamic nucleus (PSTN) and the ventrally adjacent calbindin nucleus (CbN) form a nuclear complex in the posterior lateral hypothalamic area (LHA), recently characterized as connected with the central nucleus of the amygdala (CEA). The aim of the present work is to analyze in detail the projections from the amygdala into the PSTN/CbN, also focusing on pathways into the LHA. After fluorogold injections into the PSTN/CbN, the medial part of the CEA (CEAm) appears to be the main supplier of projections from the CEA. Other amygdalar nuclei contribute to the innervation of the PSTN/CbN complex, including the anterior part of the basomedial nucleus (BMAa). Injections of the anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHAL), into the CEAm and BMAa revealed that projections from the CEAm follow two pathways into the LHA: a dorsal pathway formed by axons that also innervate the paraventricular hypothalamic nucleus, the anterior perifornical LHA and the PSTN, and a ventral pathway that runs laterally adjacent to the ventrolateral hypothalamic tract (vlt) and ends in the CbN. By contrast, the BMAa and other telencephalic structures, such as the fundus striatum project to the CbN via the ventral pathway. Confirming the microscopic observation, a semi-quantitative analysis of the density of these projections showed that the PSTN and the CbN are the major hypothalamic targets for the projections from the CEAm and the BMAa, respectively. PSTN and CbN receive these projections through distinct dorsal and ventral routes in the LHA. The ventral pathway forms a differentiated tract, named here the ventrolateral amygdalo-hypothalamic tract (vlah), that is distinct from, but runs adjacent to, the vlt. Both the vlt and the vlah had been previously described as forming an olfactory path into the LHA. These results help to better characterize the CbN within the PSTN/CbN complex and are discussed in terms of the functional organization of the network involving the

  15. Preliminary Slope Stability Study Using Slope/ W

    International Nuclear Information System (INIS)

    Nazran Harun; Mohd Abd Wahab Yusof; Kamarudin Samuding; Mohd Muzamil Mohd Hashim; Nurul Fairuz Diyana Bahrudin

    2014-01-01

    Analyzing the stability of earth structures is the oldest type of numerical analysis in geotechnical engineering. Limit equilibrium types of analyses for assessing the stability of earth slopes have been in use in geotechnical engineering for many decades. Modern limit equilibrium software is making it possible to handle ever-increasing complexity within an analysis. It is being considered as the potential method in dealing with complex stratigraphy, highly irregular pore-water pressure conditions, various linear and nonlinear shear strength models and almost any kind of slip surface shape. It allows rapid decision making by providing an early indication of the potential suitability of sites based on slope stability analysis. Hence, a preliminary slope stability study has been developed to improve the capacity of Malaysian Nuclear Agency (Nuclear Malaysia) in assessing potential sites for Borehole Disposal for Disused Sealed Radioactive Sources. The results showed that geometry of cross section A-A ' , B-B ' , C-C ' and D-D ' achieved the factor of safety not less than 1.4 and these are deemed acceptable. (author)

  16. Anterior referencing of tibial slope in total knee arthroplasty considerably influences knee kinematics : a musculoskeletal simulation study

    NARCIS (Netherlands)

    Marra, Marco Antonio; Strzelczak, Marta; Heesterbeek, Petra J.C.; van de Groes, Sebastiaan A.W.; Janssen, Dennis W.; Koopman, Bart F.J.M.; Wymenga, Ate B.; Verdonschot, Nico J.J.

    2017-01-01

    Purpose: In total knee arthroplasty (TKA), the posterior tibial slope is not always reconstructed correctly, and the knee ligaments may become too tight in flexion. To release a tight flexion gap, surgeons can increase the posterior tibial slope using two surgical resection techniques: the anterior

  17. Rock Slope Design Criteria

    Science.gov (United States)

    2010-06-01

    Based on the stratigraphy and the type of slope stability problems, the flat lying, Paleozoic age, sedimentary : rocks of Ohio were divided into three design units: 1) competent rock design unit consisting of sandstones, limestones, : and siltstones ...

  18. Dark Slope Streaks

    Science.gov (United States)

    2004-01-01

    13 March 2004 Martian slope streaks occur in the regions most heavily mantled by fine, dry dust, particularly Tharsis, Arabia, and the knobby areas between Amazonis and Cerberus. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some examples of dark slope streaks off of buttes, mesas, and massifs in a dust-mantled crater in central Arabia Terra. New slope streaks form from time to time in the modern martian environment; the streaks in this image probably formed within the past decade. To create them, dust slid or avalanched down the slopes in an almost liquid-like manner. The image is located near 6.8oN, 321.7oW. The picture covers an area 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  19. Unstable slope management program.

    Science.gov (United States)

    2009-08-01

    This Rapid Response Project gathered information on existing unstable slope management programs, with a : focus on asset management practices in the United States and overseas. On the basis of this study, the research : team summarized and recommende...

  20. Rock slope design guide.

    Science.gov (United States)

    2011-04-01

    This Manual is intended to provide guidance for the design of rock cut slopes, rockfall catchment, and : rockfall controls. Recommendations presented in this manual are based on research presented in Shakoor : and Admassu (2010) entitled Rock Slop...

  1. Posterior Cruciate Ligament Injury

    Science.gov (United States)

    ... the thighbone (femur) to the shinbone (tibia). The anterior and posterior cruciate ligaments form an "X" in the center of the knee. Although a posterior cruciate ligament injury generally causes less pain, disability and knee instability than does an ACL ...

  2. The effect of tibial slope on the biomechanics of cruciate-retaining TKA : a musculoskeletal simulation study

    NARCIS (Netherlands)

    Marra, Marco A.; Strzelczak, Marta; Heesterbeek, Petra J.C.; van de Groes, Sebastiaan; Janssen, Dennis W.; Koopman, Bart F.J.M.; Wymenga, Ate B.; Verdonschot, Nico J.J.

    2017-01-01

    INTRODUCTION: Tibial slope can affect the outcomes of Total Knee Arthroplasty (TKA). More posterior slope potentially helps releasing a too tight flexion gap and it is generally associated with a wider range of post-operative knee flexion. However, the mechanism by which tibial slope affects the

  3. Nanotherapy for posterior eye diseases.

    Science.gov (United States)

    Kaur, Indu Pal; Kakkar, Shilpa

    2014-11-10

    It is assumed that more than 50% of the most enfeebling ocular diseases have their origin in the posterior segment. Furthermore, most of these diseases lead to partial or complete blindness, if left untreated. After cancer, blindness is the second most dreaded disease world over. However, treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted for delivery to this segment. In this regard, nanostructured drug delivery systems are proposed to defy ocular barriers, target retina, and act as permeation enhancers in addition to providing a controlled release. Since an important step towards developing effective treatment strategies is to understand the course or a route a drug molecule needs to follow to reach the target site, the first part of the present review discusses various pathways available for effective delivery to and clearance from the posterior eye. Promise held by nanocarrier systems, viz. liposomes, nanoparticles, and nanoemulsion, for effective delivery and selective targeting is also discussed with illustrative examples, tables, and flowcharts. However, the applicability of these nanocarrier systems as self-administration ocular drops is still an unrealized dream which is in itself a huge technological challenge. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Posterior labrocapsular periosteal sleeve avulsion complicating locked posterior shoulder dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Simons, P. [Department of Radiology, Onze Lieve Vrouwe Hospital, Aalst (Belgium)]|[Department of Radiology, Leiden University Medical Centre, Leiden (Netherlands); Joekes, E.; Bloem, J.L. [Department of Radiology, Leiden University Medical Centre, Leiden (Netherlands); Nelissen, R.G.H.H. [Department of Orthopaedic Surgery, Leiden University Medical Centre (Netherlands)

    1998-10-01

    This case presents the imaging features of a posterior shoulder dislocation complicated by a rare but surgically relevant lesion of the posterior labrum. Due to the attachment of the posterior capsule to the posterior portion of the labrum, which in itself is attached to the posterior scapular periosteum, stripping of the labrum by the posterior capsule resulted in a posterior labrocapsular periosteal sleeve avulsion. (orig.) With 4 figs., 5 refs.

  5. Slope earthquake stability

    CERN Document Server

    Changwei, Yang; Jing, Lian; Wenying, Yu; Jianjing, Zhang

    2017-01-01

    This book begins with the dynamic characteristics of the covering layerbedrock type slope, containing monitoring data of the seismic array, shaking table tests, numerical analysis and theoretical derivation. Then it focuses on the landslide mechanism and assessment method. It also proposes a model that assessing the hazard area based on the field investigations. Many questions, exercises and solutions are given. Researchers and engineers in the field of Geotechnical Engineering and Anti-seismic Engineering can benefit from it.

  6. The Q-Slope Method for Rock Slope Engineering

    Science.gov (United States)

    Bar, Neil; Barton, Nick

    2017-12-01

    Q-slope is an empirical rock slope engineering method for assessing the stability of excavated rock slopes in the field. Intended for use in reinforcement-free road or railway cuttings or in opencast mines, Q-slope allows geotechnical engineers to make potential adjustments to slope angles as rock mass conditions become apparent during construction. Through case studies across Asia, Australia, Central America, and Europe, a simple correlation between Q-slope and long-term stable slopes was established. Q-slope is designed such that it suggests stable, maintenance-free bench-face slope angles of, for instance, 40°-45°, 60°-65°, and 80°-85° with respective Q-slope values of approximately 0.1, 1.0, and 10. Q-slope was developed by supplementing the Q-system which has been extensively used for characterizing rock exposures, drill-core, and tunnels under construction for the last 40 years. The Q' parameters (RQD, J n, J a, and J r) remain unchanged in Q-slope. However, a new method for applying J r/ J a ratios to both sides of potential wedges is used, with relative orientation weightings for each side. The term J w, which is now termed J wice, takes into account long-term exposure to various climatic and environmental conditions such as intense erosive rainfall and ice-wedging effects. Slope-relevant SRF categories for slope surface conditions, stress-strength ratios, and major discontinuities such as faults, weakness zones, or joint swarms have also been incorporated. This paper discusses the applicability of the Q-slope method to slopes ranging from less than 5 m to more than 250 m in height in both civil and mining engineering projects.

  7. Posterior fossa epidural hematoma

    International Nuclear Information System (INIS)

    Kushner, M.J.; Luken, M.G. III

    1983-01-01

    CT demonstrated posterior fossa epidural hematoma in three patients with head trauma in whom this diagnosis was not clinically apparent. No patient was in stupor or coma and no patient experienced a lucid interval. Only one patient had signs referable to the posterior fossa. Two patients had occipital skull fracture disclosed by plain radiographs. CT revealed a unilateral biconvex hematoma in two cases, and a bilateral hematoma with supratentorial extension in the third. All patients underwent suboccipital craniectomy and recovered. Therapeutic success in these cases was facilitated by early CT and the rapid disclosure of the unsuspected posterior fossa lesions. CT showing contiguous hematoma below and above the tentorium cerebelli after posterior head trauma is highly suggestive of epidural hematoma arising from the posterior fossa. (orig.)

  8. A Different Pitch to Slope

    Science.gov (United States)

    Wolbert, William

    2017-01-01

    The query "When are we ever going to use this?" is easily answered when discussing the slope of a line. The pitch of a roof, the grade of a road, and stair stringers are three applications of slope that are used extensively. The concept of slope, which is introduced fairly early in the mathematics curriculum has hands-on applications…

  9. Direction of Auditory Pitch-Change Influences Visual Search for Slope From Graphs.

    Science.gov (United States)

    Parrott, Stacey; Guzman-Martinez, Emmanuel; Orte, Laura; Grabowecky, Marcia; Huntington, Mark D; Suzuki, Satoru

    2015-01-01

    Linear trend (slope) is important information conveyed by graphs. We investigated how sounds influenced slope detection in a visual search paradigm. Four bar graphs or scatter plots were presented on each trial. Participants looked for a positive-slope or a negative-slope target (in blocked trials), and responded to targets in a go or no-go fashion. For example, in a positive-slope-target block, the target graph displayed a positive slope while other graphs displayed negative slopes (a go trial), or all graphs displayed negative slopes (a no-go trial). When an ascending or descending sound was presented concurrently, ascending sounds slowed detection of negative-slope targets whereas descending sounds slowed detection of positive-slope targets. The sounds had no effect when they immediately preceded the visual search displays, suggesting that the results were due to crossmodal interaction rather than priming. The sounds also had no effect when targets were words describing slopes, such as "positive," "negative," "increasing," or "decreasing," suggesting that the results were unlikely due to semantic-level interactions. Manipulations of spatiotemporal similarity between sounds and graphs had little effect. These results suggest that ascending and descending sounds influence visual search for slope based on a general association between the direction of auditory pitch-change and visual linear trend.

  10. Spondylolisthesis and Posterior Instability

    International Nuclear Information System (INIS)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D.; Simons, P.; Kuchta, J.

    2009-01-01

    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI

  11. Spondylolisthesis and Posterior Instability

    Energy Technology Data Exchange (ETDEWEB)

    Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D. (Privatpraxis fuer Upright MRT, Koeln (Germany)); Simons, P.; Kuchta, J. (Media Park Klinik, Koeln (Germany))

    2009-04-15

    We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.

  12. Posterior Elbow Dislocation

    Directory of Open Access Journals (Sweden)

    Victoria Oppenheim

    2016-09-01

    Full Text Available History of present illness: A 15-year old female presented with left elbow pain. While competing in a high school wrestling match, she extended her left arm to brace a fall and had immediate onset of sharp pain. She denied weakness or numbness of her left arm. She had no past medical history. Significant findings: Elbow dislocations are classified by the position of the radio-ulnar joint relative to the humerus.1 Images 1, 2, and 3 show a left posterior elbow dislocation; the radius and ulna are displaced posteriorly with respect to the distal humerus. The lateral view of the elbow most clearly shows this: trochlear notch of the ulna is empty and displaced posteriorly relative to the trochlea. There is no associated fracture. Images 4 and 5 show the elbow status-post reduction, demonstrating proper alignment of the distal humerus with the radius and ulna. Discussion: Traumatic dislocations of the elbow are relatively uncommon in pediatric patients, with a peak incidence at 13 to 14 years.1 Dislocations are usually posterior and occur after forced abduction and extension of the elbow.1 It is important to evaluate for an associated fracture or avulsion, which occurs in over 50% of pediatric elbow dislocations. Fractures most commonly involve the medial epicondyle, radial head and neck, or coronoid process.1 One should also consider a neurovascular injury to the ulnar or median nerve or to the brachial artery or its branches.1 Posterior elbow dislocations should be reduced as soon as possible.1 Patients should receive adequate sedation and/or analgesia. One method of reduction is the “puller” technique, during which a practitioner stabilizes the humerus, while a second practitioner applies force against the anterior forearm, with gentle traction distally.1 Post-reduction neurovascular reassessment is important. After successful reduction, patients can be immobilized in a posterior long arm splint.

  13. The Tibial Slope in Patients With Achondroplasia: Its Characterization and Possible Role in Genu Recurvatum Development.

    Science.gov (United States)

    Brooks, Jaysson T; Bernholt, David L; Tran, Kevin V; Ain, Michael C

    2016-06-01

    Genu recurvatum, a posterior resting position of the knee, is a common lower extremity deformity in patients with achondroplasia and has been thought to be secondary to ligamentous laxity. To the best of our knowledge, the role of the tibial slope has not been investigated, and no studies describe the tibial slope in patients with achondroplasia. Our goals were to characterize the tibial slope in children and adults with achondroplasia, explore its possible role in the development of genu recurvatum, and compare the tibial slope in patients with achondroplasia to that in the general population. We reviewed 252 lateral knee radiographs of 130 patients with achondroplasia seen at our clinic from November 2007 through September 2013. Patients were excluded if they had previous lower extremity surgery or radiographs with extreme rotation. We analyzed patient demographics and, on all radiographs, the tibial slope. We then compared the mean tibial slope to norms in the literature. Tibial slopes >90 degrees had an anterior tibial slope and received a positive prefix. Statistical analysis included intraclass and interclass reliability, Pearson correlation coefficient, and the Student t tests (significance, Pachondroplasia than in the general population; however, this difference diminishes as patients' age. An anterior tibial slope may predispose to a more posterior resting knee position, also known as genu recurvatum. Level IV-retrospective case series.

  14. Posterior tracheal diverticulosis.

    Science.gov (United States)

    Madan, Karan; Das, Chandan J; Guleria, Randeep

    2014-10-01

    Multiple tracheal diverticulosis is a rare clinical entity. Tracheal diverticula are usually recognized radiologically as solitary right paratracheal air collections on thoracic computed tomography examination. They are usually asymptomatic but can occasionally present with persistent symptoms. We herein report the case of a 50-year-old male patient who underwent extensive evaluation for persistent cough. Multiple posterior right paratracheal air collections were recognized on thoracic multidetector computed tomography examination, which was confirmed as multiple-acquired posterior upper tracheal diverticula on flexible bronchoscopy. The patient improved with conservative medical management.

  15. Posterior Urethral Valves

    Directory of Open Access Journals (Sweden)

    Steve J. Hodges

    2009-01-01

    Full Text Available The most common cause of lower urinary tract obstruction in male infants is posterior urethral valves. Although the incidence has remained stable, the neonatal mortality for this disorder has improved due to early diagnosis and intensive neonatal care, thanks in part to the widespread use of prenatal ultrasound evaluations. In fact, the most common reason for the diagnosis of posterior urethral valves presently is the evaluation of infants for prenatal hydronephrosis. Since these children are often diagnosed early, the urethral obstruction can be alleviated rapidly through catheter insertion and eventual surgery, and their metabolic derangements can be normalized without delay, avoiding preventable infant mortality. Of the children that survive, however, early diagnosis has not had much effect on their long-term prognosis, as 30% still develop renal insufficiency before adolescence. A better understanding of the exact cause of the congenital obstruction of the male posterior urethra, prevention of postnatal bladder and renal injury, and the development of safe methods to treat urethral obstruction prenatally (and thereby avoiding the bladder and renal damage due to obstructive uropathy are the goals for the care of children with posterior urethral valves[1].

  16. Slope failure simulations with MPM

    NARCIS (Netherlands)

    Vardon, P.J.; Wang, B.; Hicks, M.A.

    2017-01-01

    The simulation of slope failures, including both failure initiation and development, has been modelled using the material point method (MPM). Numerical case studies involving various slope angles, heterogeneity and rainfall infiltration are presented. It is demonstrated that, by utilising a

  17. Slope Failure Simulations with MPM

    NARCIS (Netherlands)

    Vardon, P.J.; Wang, B.; Hicks, M.A.

    2017-01-01

    The simulation of slope failures, including both failure initiation and development, has been modelled using the material point method. By utilising a constitutive model which encompasses, in a simplified manner, both pre- and post-failure behaviour, the majority of types of geotechnical slope

  18. Posterior Reversible Encephalopathy (PRES)

    International Nuclear Information System (INIS)

    Moron E, Fanny E; Diaz Marchan, Pedro

    2005-01-01

    The Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical Syndrome composed of cephalea, alteration in vision and convulsions, usually observed in patients with sudden elevation of arterial pressure. The imagenologic evidence shows reversible vasogenic brain edema without stroke. Its location is predominantly posterior; it affects the cortex and the subcortical white matter of the occipital, parietal and temporal lobes. The treatment with antihypertensive drugs and the removing of immunosupressor medication are generally associated with complete neurological recovery; this is reflected also in the images which return to their basal condition. The untreated hypertension, on the other side, can result in a progressive defect of the autoregulation system of the central nervous system with cerebral hemorrhage, irreversible brain stroke, coma and death

  19. Posterior Horn of Medial Meniscal Peripheral Capsular Lesion: The Arthroscopic Repair Technique Working in the Posterior Compartment.

    Science.gov (United States)

    Kongmalai, Pinkawas; Chernchujit, Bancha

    2016-08-01

    A posterior horn of medial meniscal peripheral capsular is usually associated with the anterior cruciate ligament injury. The conventional repair technique with the camera in the anterolateral portal cannot precisely restore the slope capsular synovium to the original attachment point. We present the arthroscopic technique for improving the accuracy and quality of the repair by working in the posterior compartment. When the posterolateral portal is used as the viewing portal, the accuracy of repair is improved because we can assess the full extent of the lesion and lift the sagging peripheral tissue to the more central part.

  20. Slope failure investigation management system.

    Science.gov (United States)

    2013-03-01

    Highway slopes are exposed to a variety of environmental and climatic conditions, such as deforestation, cycles of : freezing and thawing weather, and heavy storms. Over time, these climatic conditions, in combination with other : factors such as geo...

  1. Light and Dark Slope Streaks

    Science.gov (United States)

    2004-01-01

    21 July 2004 Dark slope streaks are a common feature on slopes thickly-mantled by dust, especially in the Tharsis, Arabia, and western Amazonis regions of Mars. Less common are light-toned slope streaks, which often occur in the same area as dark streaks. They are most common in Arabia Terra, and some are shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. Slope streaks are probably the result of sudden avalanches of extremely dry dust. The behavior of the avalanching dust is somewhat fluid-like, and new streaks have been observed to form over intervals of a few months to a Mars year. This image is located near 13.4oN, 340.3oW, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  2. Compost for steep slope erosion.

    Science.gov (United States)

    2008-06-01

    This study was initiated to develop guidelines for maintenance erosion control measures for steep slopes. The study focused on evaluating and monitoring KY-31 fescue germination rates using two media treatments 1) 100 percent by weight compost and 2)...

  3. North Slope (Wahluke Slope) expedited response action cleanup plan

    International Nuclear Information System (INIS)

    1994-02-01

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi 2 (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives

  4. North Slope (Wahluke Slope) expedited response action cleanup plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-02-01

    The purpose of this action is to mitigate any threat to public health and the environment from hazards on the North Slope and meet the expedited response action (ERA) objective of cleanup to a degree requiring no further action. The ERA may be the final remediation of the 100-I-3 Operable Unit. A No Action record of decision (ROD) may be issued after remediation completion. The US Department of Energy (DOE) currently owns or administers approximately 140 mi{sup 2} (about 90,000 acres) of land north and east of the Columbia River (referred to as the North Slope) that is part of the Hanford Site. The North Slope, also commonly known as the Wahluke Slope, was not used for plutonium production or support facilities; it was used for military air defense of the Hanford Site and vicinity. The North Slope contained seven antiaircraft gun emplacements and three Nike-Ajax missile positions. These military positions were vacated in 1960--1961 as the defense requirements at Hanford changed. They were demolished in 1974. Prior to government control in 1943, the North Slope was homesteaded. Since the initiation of this ERA in the summer of 1992, DOE signed the modified Hanford Federal Agreement and Consent Order (Tri-Party Agreement) with the Washington Department of Ecology (Ecology) and the US Environmental Protection Agency (EPA), in which a milestone was set to complete remediation activities and a draft closeout report by October 1994. Remediation activities will make the North Slope area available for future non-DOE uses. Thirty-nine sites have undergone limited characterization to determine if significant environmental hazards exist. This plan documents the results of that characterization and evaluates the potential remediation alternatives.

  5. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won; Song, Chang Joon; Song, Soon-Young; Koo, Ja Hong; Kim, Man Deuk

    2001-01-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  6. Posterior Urethral Strictures

    Directory of Open Access Journals (Sweden)

    Joel Gelman

    2015-01-01

    Full Text Available Pelvic fracture urethral injuries are typically partial and more often complete disruptions of the most proximal bulbar and distal membranous urethra. Emergency management includes suprapubic tube placement. Subsequent primary realignment to place a urethral catheter remains a controversial topic, but what is not controversial is that when there is the development of a stricture (which is usually obliterative with a distraction defect after suprapubic tube placement or urethral catheter removal, the standard of care is delayed urethral reconstruction with excision and primary anastomosis. This paper reviews the management of patients who suffer pelvic fracture urethral injuries and the techniques of preoperative urethral imaging and subsequent posterior urethroplasty.

  7. Posterior Urethral Strictures

    Science.gov (United States)

    Gelman, Joel; Wisenbaugh, Eric S.

    2015-01-01

    Pelvic fracture urethral injuries are typically partial and more often complete disruptions of the most proximal bulbar and distal membranous urethra. Emergency management includes suprapubic tube placement. Subsequent primary realignment to place a urethral catheter remains a controversial topic, but what is not controversial is that when there is the development of a stricture (which is usually obliterative with a distraction defect) after suprapubic tube placement or urethral catheter removal, the standard of care is delayed urethral reconstruction with excision and primary anastomosis. This paper reviews the management of patients who suffer pelvic fracture urethral injuries and the techniques of preoperative urethral imaging and subsequent posterior urethroplasty. PMID:26691883

  8. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  9. Evolution of steep Martian slopes

    Science.gov (United States)

    Sullivan, Robert John, Jr.

    1992-01-01

    The physical properties and evolution of steep slopes on the planet Mars are examined. Where martian slopes are steepest and of greatest relief, the slope morphology is distinctive and characterized by regular, alternating spurs and gullies. Previous workers identified these martian gullies as dry debris avalanche chutes, partially because a nonspecific 'dry mass-wasting' explanation seemed compatible, initially, with current surface conditions. An evacuated avalanche chute provides the opportunity to back analyze the stability of the mobile layer of the chute at the time of its failure. For the martian slope problem a new stability back-analysis technique was developed which incorporates the third dimension (chute width) into the back-analysis calculation, allowing unambiguous determination of the average cohesion and angle of internal friction of the mobile layer. A series of trials was performed to investigate the effects of gravitational acceleration, average slope angle, and average mobile layer density, cohesion, and angle of internal friction on the size and shape of the transverse chute cross-section. Results indicate that: (1) variations in density, gravitational acceleration, and cohesion affect the overall size of the cross-section but not its width:depth ratio, and (2) the contrast between average slope angle and angle of internal friction is most influential on the width:depth ratio of the cross-section. The difference between these two parameters is inversely proportional to the width:depth ratio. Application of the three-dimensional back-analysis technique to proposed martian avalanche chutes yields values of cohesion and angle of internal friction of the mobile layers that are similar mechanically (without genetic implications) to those of terrestrial glacial till, a poorly sorted material with moderate inter-grain cohesion, or lunar soils under normal stresses representative of (lunar) depths of between ten and twenty meters. Material of these

  10. Irreducible Traumatic Posterior Shoulder Dislocation

    Directory of Open Access Journals (Sweden)

    Blake Collier

    2017-01-01

    Full Text Available History of present illness: A 22-year-old male presented to the Emergency Department complaining of right shoulder pain after a motocross accident. He was traveling at approximately 10 mph around a turn when he lost control and was thrown over the handlebars, landing directly on his right shoulder. On arrival, he was holding his arm in adduction and internal rotation. An area of swelling was noted over his anterior shoulder. He was unable to abduct his shoulder. No humeral gapping was noted. He had normal neuro-vascular status distal to the injury. Significant findings: Radiographs demonstrated posterior displacement of the humeral head on the “Y” view (see white arrow and widening of the glenohumeral joint space on anterior-posterior view (see red arrow. The findings were consistent with posterior dislocation and a Hill-Sachs type deformity. Sedation was performed and reduction was attempted using external rotation, traction counter-traction. An immediate “pop” was felt during the procedure. Post-procedure radiographs revealed a persistent posterior subluxation with interlocking at posterior glenoid. CT revealed posterior dislocation with acute depressed impaction deformity medial to the biceps groove with the humeral head perched on the posterior glenoid, interlocked at reverse Hill-Sachs deformity (see blue arrow. Discussion: Posterior shoulder dislocations are rare and represent only 2% of all shoulder dislocations. Posterior shoulder dislocations are missed on initial diagnosis in more than 60% of cases.1 Posterior shoulder dislocations result from axial loading of the adducted and internally rotated shoulder, violent muscle contractions (resulting from seizures or electrocution, a direct posterior force applied to the anterior shoulder.1 Physical findings include decreased anterior prominence of the humeral head, increased palpable posterior prominence of the humeral head below the acromion, increased palpable prominence of the

  11. The effect of tibial slope in acute ACL-insufficient patients on concurrent meniscal tears.

    Science.gov (United States)

    Markl, Isabelle; Zantop, Thore; Zeman, Florian; Seitz, Johannes; Angele, Peter

    2015-08-01

    The aim of this study is to evaluate the effect of the medial and lateral posterior tibial slope (MPTS, LPTS) in patients with acutely ruptured ACL on the menisci. It was hypothesized that medial and lateral meniscus lesions are seen more often with high PTS (posterior tibial slope). We hypothesized that in case of a high tibial slope a possible meniscus lesion is more often located in the posterior horn of the meniscus than in knees with a low tibial slope. We identified 537 patients with ACL insufficiency between 2012 and 2013. Of these, 71 patients were eligible for the study according to the study's criteria. PTS was measured via MRI and classified into two groups: >10° for high tibial slope and ≤10° for low tibial slope. Any meniscal lesion was documented during arthroscopic ACL reconstruction and evaluated regarding meniscal lesion patterns with high and low PTS, taking into account the type and the location of the tear (anterior horn, intermediate part and posterior horn). Statistical analysis for differences in meniscal lesion was performed using Chi-square tests and McNemar tests for dependent variables. The level of significance was set at p ≤ 0.05. High PTS (MPTS and LPTS) was associated with a higher incidence of meniscal lesions with an odds ratio of 2.11, respectively, 3.44; however, no statistical significance was found. Among the total number of ACL-insufficient knees studied, the meniscal lesion spread more often to the posterior part in the group with a low PTS. In contrast, less damage of the posterior horn of the meniscus could be found in the group with a high PTS. High PTS seems to predetermine for meniscal lesion in an acute ACL-insufficient knee. More damage to the posterior part of the menisci could generally be seen but was not associated with a high PTS. There was no statistical significance to support the initial hypothesis. Further research is needed to find out if factors other than tibial slope are risk factors for meniscal

  12. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  13. Endoscopic Management of Posterior Epistaxis

    OpenAIRE

    Paul, J.; Kanotra, Sohit Paul; Kanotra, Sonika

    2011-01-01

    The traditional method of management of posterior epistaxis has been with anteroposterior nasal packing. Apart from the high failure rate of 26–50% reported in various series, nasal packing is associated with marked discomfort and several complications. In order to avoid nasal packing, we started doing endoscopic cauterization in cases of posterior epistaxis. A total of 23 patients with posterior epistaxis were subjected to nasal endoscopy with the intent to stop bleeding by cauterization of ...

  14. Hidroma subdural na fossa posterior

    Directory of Open Access Journals (Sweden)

    José Carlos Vasques

    1970-03-01

    Full Text Available Os autores relatam um caso de hidroma subdural na fossa craniana posterior conseqüente a traumatismo na região occipital. O paciente foi operado com pleno sucesso. A raridade da localização de hidroma na fossa posterior é salientada, sendo discutidos os possíveis mecanismos etio-patogênicos.

  15. Impact of slope inclination on salt accumulation

    Science.gov (United States)

    Nachshon, Uri

    2017-04-01

    Field measurements indicated on high variability in salt accumulation along natural and cultivated slopes, even for relatively homogeneous soil conditions. It was hypothesised that slope inclination has an impact on the location of salt accumulation along the slope. A set of laboratory experiments and numerical models were used to explore the impact of slope inclination on salt accumulation. It was shown, experimentally, that for conditions of saline water source at the lower boundary of the slope - salt accumulates in low concentrations and homogeneously along the entire slope, for moderate slopes. However, as inclination increases high salt concentrations were observed at the upper parts of the slope, leaving the lower parts of the slope relatively free of salt. The traditional flow and transport models did not predict the experimental observations as they indicated also for the moderate slopes on salt accumulation in the elevated parts of the slope, away of the saline water source. Consequently - a conceptual model was raised to explain the laboratory observations. It was suggested that the interactions between slope angle, evaporation rates, hydraulic conductivity of the medium and distribution of wetness along the slope affect the saline water flow path through the medium. This lead to preferential flow path close to the soil-atmosphere interface for the steep slopes, which leads to constant wash of the salts from the evaporation front upward towards the slope upper parts, whereas for the moderate slopes, flow path is below the soil-atmosphere interface, therefore salt that accumulates at the evaporation front is not being transported upward. Understanding of salt dynamics along slopes is important for agricultural and natural environments, as well as for civil engineering purposes. Better understanding of the salt transport processes along slopes will improve our ability to minimize and to cope with soil salinization processes. The laboratory experiments and

  16. through the posterior tympanotomy

    Directory of Open Access Journals (Sweden)

    Emilia B. Karchier

    2016-07-01

    Full Text Available Introduction : The anterior epitympanum recess (AER is a common place of the development of the cholesteatoma, which is why removal of the matrix from this area plays a key role in the surgical treatment of chronic otitis media. Aim : To evaluate the intraoperative visibility of AER in endoscopic optics in comparison to microscopic optics and to determine the prevalence of cholesteatoma in various types of construction of the AER. Study design: Retrospective analysis of intraoperative search. Material and methods : The study included 55 patients treated in the Department of Otolaryngology, Medical University of Warsaw within the years 2009–2011, who underwent endoscopy-assisted canal wall up tympanoplasty with posterior tympanotomy. The type of construction of the AER – cellular or dome-shaped – was determined. Results : Cellular type of recess was found intraoperatively in 32% of ears and dome-shaped in 68% of the study group. The population with chronic otitis media does not differ significantly compared to the general population in terms of the construction of the anterior epitympanum recess (p = 0.668108; χ 2 = 0.1838235, df = 1. Among the ears with cholesteatoma a cellular AER was found in 48.3% of cases and a dome-shaped AER was found in 51.7%. Conclusions : The cellular type of AER was significantly more frequent in ears with cholesteatoma (p < 0.01, χ 2 = 29.86492, df = 1. Level of evidence: 1b.

  17. Reversible Posterior Leukoencephalopathy Syndrome Induced by Pazopanib

    International Nuclear Information System (INIS)

    Chelis, Leonidas; Kakolyris, Stylianos; Souftas, Vasilios; Amarantidis, Kiriakos; Xenidis, Nikolaos; Chamalidou, Eleni; Dimopoulos, Prokopios; Michailidis, Prodromos; Christakidis, Evagelos; Prassopoulos, Panagiotis

    2012-01-01

    The reversible posterior leukoencephalopathy syndrome is a clinical/radiological syndrome characterized by headache, seizures, impaired vision, acute hypertension, and typical magnetic resonance imaging findings. There are several reports in the literature that depict its occurrence in cancer patients. The list of common anticancer and supportive care drugs that predispose to reversible posterior leukoencephalopathy syndrome is expanding and includes not only a large number of chemotherapeutic agents but also an increased number of new targeted drugs, particularly angiogenesis inhibitors such as bevacizumab,sorefenib and sunitinib. Pazopanib is an oral tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and c-Kit which after a positive phase III randomized clinical trial in patients with advanced renal cell cancer received FDA approval for the treatment of advanced renal cell carcinoma. Until now no cases of reversible posterior leukoencephalopathy syndrome induced by pazopanib have been reported. We present the case of a 40 years old female patient with heavily pre-treated metastatic renal cell carcinoma who received pazopanib as salvage treatment. After 21 days of pazopanib therapy the patient referred to the emergency department with epileptic seizure, impaired vision at both eyes and headache. MRI of the brain revealed subcortical oedema at the occipital and parietal lobes bilaterally. She was treated with anticonvulsants, i.v. administration of mannitol and antihypertensives and she recovered completely from her symptoms and was discharged on the tenth hospital day. A brain MRI performed 3 weeks after showed that the subcortical oedema had been subsided. In conclusion this is the first case of pazopanib induced reversible posterior leukoencephalopathy syndrome. Although usually reversible, this syndrome is a serious and potentially life threatening adverse effect, if untreated, that should

  18. Classification of posterior vitreous detachment

    Science.gov (United States)

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2014-01-01

    Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography (OCT). By biomicroscopy, the vitreous condition is determined based on the presence or absence of a PVD. The PVD then is classified as either a complete posterior vitreous detachment (C-PVD) or a partial posterior vitreous detachment (P-PVD). A C-PVD is further divided into a C-PVD with collapse and a C-PVD without collapse, while a P-PVD is divided into a P-PVD with shrinkage of the posterior hyaloid membrane (P-PVD with shrinkage) and a P-PVD without shrinkage of the posterior hyaloid membrane (P-PVD without shrinkage). A P-PVD without shrinkage has a subtype characterized by vitreous gel attachment through the premacular hole in a posterior hyaloid membrane to the macula (P-PVD without shrinkage [M]). By OCT, a shallow PVD is classified as the absence of a shallow PVD or as a shallow PVD. A shallow PVD is then subclassified as a shallow PVD without shrinkage of the posterior vitreous cortex, a shallow PVD with shrinkage of the posterior vitreous cortex, and a peripheral shallow PVD. A shallow PVD without shrinkage of the posterior vitreous cortex has two subtypes: an age-related shallow PVD and a perifoveal PVD associated with a macular hole. PMID:24376338

  19. VT Lidar Slope (1 meter) - 2005 - Essex

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) This metadata applies to the following collection area(s): Essex County 2005 1m and related SLOPE datasets. Created using ArcGIS "SLOPE" command...

  20. Gravity-induced stresses in finite slopes

    Science.gov (United States)

    Savage, W.Z.

    1994-01-01

    An exact solution for gravity-induced stresses in finite elastic slopes is presented. This solution, which is applied for gravity-induced stresses in 15, 30, 45 and 90?? finite slopes, has application in pit-slope design, compares favorably with published finite element results for this problem and satisfies the conditions that shear and normal stresses vanish on the ground surface. The solution predicts that horizontal stresses are compressive along the top of the slopes (zero in the case of the 90?? slope) and tensile away from the bottom of the slopes, effects which are caused by downward movement and near-surface horizontal extension in front of the slope in response to gravity loading caused by the additional material associated with the finite slope. ?? 1994.

  1. Slope protection for artificial island

    Energy Technology Data Exchange (ETDEWEB)

    Czerniak, M.T.; Collins, J.I.; Shak, A.T.

    1981-08-01

    The technology under development to protect artificial-island production platforms from Arctic sea and ice damage involves three major considerations: (1) sea conditions during the ice-free season, (2) ice conditions during winter, and (3) construction constraints imposed by material availability, transportation problems, and length of the construction season. So far, researchers have evaluated 15 different slope-protection systems on the basis of reliability, construction-cost, and maintenance-cost factors, choosing 8 candidates for wave and ice model testing. The cases of interest involve exploration and production islands in shallow and deeper water applications.

  2. Variations of posterior vitreous detachment

    OpenAIRE

    Kakehashi, A.; Kado, M.; Akiba, J.; Hirokawa, H.

    1997-01-01

    AIMS—To identify variations in posterior vitreous detachment (PVD) and establish a clinical classification system for PVD.
METHODS—400 consecutive eyes were examined using biomicroscopy and vitreous photography and classified the PVD variations—complete PVD with collapse, complete PVD without collapse, partial PVD with thickened posterior vitreous cortex (TPVC), or partial PVD without TPVC.
RESULTS—In each PVD type, the most frequently seen ocular pathologies were as follows: in complete PVD ...

  3. Unilateral spatial neglect after posterior parietal damage.

    Science.gov (United States)

    Vallar, Giuseppe; Calzolari, Elena

    2018-01-01

    Unilateral spatial neglect is a disabling neurologic deficit, most frequent and severe after right-hemispheric lesions. In most patients neglect involves the left side of space, contralateral to a right-hemispheric lesion. About 50% of stroke patients exhibit neglect in the acute phase. Patients fail to orient, respond to, and report sensory events occurring in the contralateral sides of space and of the body, to explore these portions of space through movements by action effectors (eye, limbs), and to move the contralateral limbs. Neglect is a multicomponent higher-level disorder of spatial awareness, cognition, and attention. Spatial neglect may occur independently of elementary sensory and motor neurologic deficits, but it can mimic and make them more severe. Diagnostic tests include: motor exploratory target cancellation; setting the midpoint of a horizontal line (bisection), that requires the estimation of lateral extent; drawing by copy and from memory; reading, assessing neglect dyslexia; and exploring the side of the body contralateral to the lesion. Activities of daily living scales are also used. Patients are typically not aware of neglect, although they may exhibit varying degrees of awareness toward different components of the deficit. The neural correlates include lesions to the inferior parietal lobule of the posterior parietal cortex, which was long considered the unique neuropathologic correlate of neglect, to the premotor and to the dorsolateral prefrontal cortices, to the posterior superior temporal gyrus, at the temporoparietal junction, to subcortical gray nuclei (thalamus, basal ganglia), and to parietofrontal white-matter fiber tracts, such as the superior longitudinal fascicle. Damage to the inferior parietal lobule of the posterior parietal cortex is specifically associated with the mainly egocentric, perceptual, and exploratory extrapersonal, and with the personal, bodily components of neglect. Productive manifestations, such as

  4. Mycorrhizal aspects in slope stabilisation

    Science.gov (United States)

    Graf, Frank

    2016-04-01

    In order to re-colonise and stabilise slopes affected by superficial soil failure with plants essential requirements have to be met: the plants must grow the plants must survive sustainably plant succession must start and continuously develop These requirements, however, are anything but easy given, particularly under the often hostile environmental conditions dominating on bare and steep slopes. Mycorrhizal fungi, the symbiotic partners of almost all plants used in eco-engineering, are said to improve the plants' ability to overcome periods governed by strongly (growth) limiting factors. Subsequently, results of investigations are presented of mycorrhizal effects on different plant and soil functions related to eco-engineering in general and soil and slope stabilisation in particular. Generally, inoculation yielded higher biomass of the host plants above as well as below ground. Furthermore, the survival rate was higher for mycorrhized compared to non-mycorrhized plants, particularly under extreme environmental conditions. However, the scale of the mycorrhizal impact may be species specific of both the plant host as well as the fungal partner(s) and often becomes evident only after a certain time lag. Depending on the plant-fungus combination the root length per soil volume was found to be between 0 and 2.5 times higher for inoculated compared to non-inoculated specimens. On an alpine graded ski slope the survival of inoculated compared to non-treated Salix herbacea cuttings was significant after one vegetation period only for one of the three added mycorrhizal fungus species. However, after three years all of the inoculated plantlets performed significantly better than the non-inoculated controls. The analysis of the potential for producing and stabilising soil aggregates of five different ectomycorrhizal fungi showed high variation and, for the species Inocybe lacera, no significant difference compared to untreated soil. Furthermore, inoculation of Salix

  5. The Influence of Shales on Slope Instability

    Science.gov (United States)

    Stead, Doug

    2016-02-01

    Shales play a major role in the stability of slopes, both natural and engineered. This paper attempts to provide a review of the state-of-the-art in shale slope stability. The complexities of shale terminology and classification are first reviewed followed by a brief discussion of the important physical and mechanical properties of relevance to shale slope stability. The varied mechanisms of shale slope stability are outlined and their importance highlighted by reference to international shale slope failures. Stability analysis and modelling of anisotropic rock slope masses are briefly discussed and the potential role of brittle rock fracture and damage highlighted. A short review of shale slopes in open pits is presented.

  6. Anterior referencing of tibial slope in total knee arthroplasty considerably influences knee kinematics: a musculoskeletal simulation study.

    Science.gov (United States)

    Marra, Marco A; Strzelczak, Marta; Heesterbeek, Petra J C; van de Groes, Sebastiaan A W; Janssen, Dennis W; Koopman, Bart F J M; Wymenga, Ate B; Verdonschot, Nico J J

    2017-05-12

    In total knee arthroplasty (TKA), the posterior tibial slope is not always reconstructed correctly, and the knee ligaments may become too tight in flexion. To release a tight flexion gap, surgeons can increase the posterior tibial slope using two surgical resection techniques: the anterior tibial cortex (ACR) or the centre of tibial plateau (CPR) referencing. It is not known how this choice affects the knee laxity and function during activities of daily living. The aim of this study was to investigate the effect of tibial slope on knee laxity, kinematics and forces during a squatting activity using computer simulation techniques. We hypothesised that the effects depend on the referencing technique utilised. A validated musculoskeletal model of TKA was used. Knee laxity tests were simulated in flexion and extension. Then, a squat motion was simulated to calculate: movement of the tibiofemoral joint (TFJ) contact points and patello-femoral joint (PFJ) contact force. All analyses were repeated with more anterior (-3°), neutral (0°), and more posterior tibial slope (+3°, +6°, +9°), and with two referencing techniques (ACR, CPR). Knee laxities increased dramatically with more posterior slope with the ACR technique (up to 400%), both in flexion and in extension. The CPR technique, instead, had much smaller effects (up to 42% variations). During squatting, more slope with the ACR technique resulted in larger movements of the TFJ contact point. The PFJ contact force decreased considerably with more slope with the CPR technique (12% body weight reduction every 3° more posterior slope), thanks to the preservation of the patellar height and quadriceps-femur load sharing. ACR technique alters considerably the knee laxity, both in flexion and extensions, and surgeons should be cautious about its use. More slope with CPR technique induces more favourable TFJ kinematics and loading of the knee extensor apparatus and does not substantially alter knee laxity. Preferably, the

  7. Endoscopic management of posterior epistaxis.

    Science.gov (United States)

    Paul, J; Kanotra, Sohit Paul; Kanotra, Sonika

    2011-04-01

    The traditional method of management of posterior epistaxis has been with anteroposterior nasal packing. Apart from the high failure rate of 26-50% reported in various series, nasal packing is associated with marked discomfort and several complications. In order to avoid nasal packing, we started doing endoscopic cauterization in cases of posterior epistaxis. A total of 23 patients with posterior epistaxis were subjected to nasal endoscopy with the intent to stop bleeding by cauterization of the bleeding vessel. Of these, in four cases unsuspected diagnosis was made. Of the remaining 19, in three patients, the bleeding point could not be localized accurately and these patients were managed by anteroposterior packing. The rest of the 16 patients were managed by endoscopic cauterization. In four patients, there was recurrence of bleeding within 24 h. In one of these, cauterization controlled the bleeding while in the rest nasal packing had to be resorted to. Thus, of the 23 patients of posterior epistaxis subjected to nasal endoscopy, we could avoid nasal packing in 17 (74%). To conclude, endoscopic nasal cauterization is recommended as the first line to treatment in all cases of posterior epistaxis. This will not only prevent the uncomfortable and potentially dangerous nasal packing but also help in finding the underlying pathology.

  8. The effect of tibial slope on the biomechanics of cruciate-retaining total knee arthroplasty : A musculoskeletal simulation study

    NARCIS (Netherlands)

    Marra, Marco Antonio; Strzelczak, Marta; Heesterbeek, Petra J.C.; van de Groes, Sebastiaan A.W.; Janssen, Dennis W.; Koopman, H.F.J.M.; Wymenga, A.B.; Verdonschot, N.J.J.

    2017-01-01

    Introduction/Aim: More posterior tibial slope (PTS) can prevent flexion gap tightness in cruciate-retaining Total Knee Arthroplasty (TKA) and help achieving better knee function. However, the influence of PTS on knee function during activities of daily living (ADLs) is scarcely documented. The aim

  9. Rethinking "posterior" tongue-tie.

    Science.gov (United States)

    Douglas, Pamela Sylvia

    2013-12-01

    Currently, many clinicians who help with breastfeeding problems are diagnosing "posterior" tongue-tie in infants and performing or referring for frenotomy. In this "Speaking Out" article, I argue that the diagnosis of "posterior" tongue-tie has successfully raised awareness of the importance of impaired tongue function in breastfeeding difficulty. However, the diagnosis of "posterior" tongue-tie also applies a reductionist, medicalized theoretical frame to the complex problem of impaired tongue function, risking unintended outcomes. Impaired tongue function arises out of multiple interacting and co-evolving factors, including the interplay between social behaviors concerning breastfeeding and mother-infant biology. Consideration of theoretical frames is vital if we are to build an evidence base through efficient use of the scarce resources available for clinical breastfeeding research and minimize unintended outcomes.

  10. Epidural hematomas of posterior fossa

    Directory of Open Access Journals (Sweden)

    Radulović Danilo

    2004-01-01

    Full Text Available Background. Posterior fossa epidural hematomas represent 7-14% of all traumatic intracranial epidural hematomas. They are most frequently encountered posttraumatic mass lesions in the posterior fossa. The aim of this study was to identify clinical features that could lead to the early diagnosis of posterior fossa epidural hematoma. Methods. Between 1980 and 2002, 28 patients with epidural hematoma of the posterior fossa were operated on at the Institute for Neurosurgery, Belgrade. Clinical course neuroradiological investigations, and the results of surgical treatment of the patients with posterior fossa epidural hematomas were analyzed retrospectively. Results. Almost two thirds of patients were younger than 16 years of age. In 20 cases injury was caused by a fall, in 6 cases by a traffic accident, and in 2 by the assault. Clinical course was subacute or chronic in two thirds of the patients. On the admission Glasgow Coma Scale was 7 or less in 9 injured, 8-14 in 14 injured, and 15 in 5 injured patients. Linear fracture of the occipital bone was radiographically evident in 19 patients, but was intraoperatively encountered in all the patients except for a 4-year old child. In 25 patients the diagnosis was established by computer assisted tomography (CAT and in 3 by vertebral angiography. All the patients were operated on via suboccipital craniotomy. Four injured patients who were preoperatively comatose were with lethal outcome. Postoperatively, 24 patients were with sufficient neurologic recovery. Conclusion. Posterior fossa epidural hematoma should be suspected in cases of occipital injury, consciousness disturbances, and occipital bone fracture. In such cases urgent CAT-scan is recommended. Early recognition early diagnosis, and prompt treatment are crucial for good neurological recovery after surgery.

  11. The Hydromechanics of Vegetation for Slope Stabilization

    Science.gov (United States)

    Mulyono, A.; Subardja, A.; Ekasari, I.; Lailati, M.; Sudirja, R.; Ningrum, W.

    2018-02-01

    Vegetation is one of the alternative technologies in the prevention of shallow landslide prevention that occurs mostly during the rainy season. The application of plant for slope stabilization is known as bioengineering. Knowledge of the vegetative contribution that can be considered in bioengineering was the hydrological and mechanical aspects (hydromechanical). Hydrological effect of the plant on slope stability is to reduce soil water content through transpiration, interception, and evapotranspiration. The mechanical impact of vegetation on slope stability is to stabilize the slope with mechanical reinforcement of soils through roots. Vegetation water consumption varies depending on the age and density, rainfall factors and soil types. Vegetation with high ability to absorb water from the soil and release into the atmosphere through a transpiration process will reduce the pore water stress and increase slope stability, and vegetation with deep root anchoring and strong root binding was potentially more significant to maintain the stability of the slope.

  12. Slope Estimation from ICESat/GLAS

    Directory of Open Access Journals (Sweden)

    Craig Mahoney

    2014-10-01

    Full Text Available We present a novel technique to infer ground slope angle from waveform LiDAR, known as the independent slope method (ISM. The technique is applied to large footprint waveforms (\\(\\sim\\ mean diameter from the Ice, Cloud and Land Elevation Satellite (ICESat Geoscience Laser Altimeter System (GLAS to produce a slope dataset of near-global coverage at \\(0.5^{\\circ} \\times 0.5^{\\circ}\\ resolution. ISM slope estimates are compared against high resolution airborne LiDAR slope measurements for nine sites across three continents. ISM slope estimates compare better with the aircraft data (R\\(^{2}=0.87\\ and RMSE\\(=5.16^{\\circ}\\ than the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM inferred slopes (R\\(^{2}=0.71\\ and RMSE\\(=8.69^{\\circ}\\ ISM slope estimates are concurrent with GLAS waveforms and can be used to correct biophysical parameters, such as tree height and biomass. They can also be fused with other DEMs, such as SRTM, to improve slope estimates.

  13. Posterior fossa meningioma (surgical experiences)

    African Journals Online (AJOL)

    Wael M. Moussa

    2012-08-27

    Aug 27, 2012 ... Abstract Introduction: Meningioma is a common tumor that represents about 30% of all intra- cranial tumors. Posterior fossa ... All patients had preoperative complete general and neurological examination, MRI of the brain with and without ..... in post-radiation nasopharyngeal carcinoma. Eur Radiol. 2009 ...

  14. Slope of the Slope Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Slope of slope was calculated from the bathymetry surface for each raster cell by applying the ArcGIS Spatial Analyst 'Slope' Tool to a previously created slope...

  15. The Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    By overcoming the barriers that limit access to financial liquidity and human resource, the Sloping Land Conversion Program (SLCP) can promote rural livelihood diversification. This paper examines this effect using a household survey data set spanning the 1999 implementation of the Sloping land c...

  16. Lattice calculus of the morphological slope transform

    NARCIS (Netherlands)

    H.J.A.M. Heijmans (Henk); P. Maragos

    1995-01-01

    textabstractThis paper presents a study of the morphological slope transform in the complete lattice framework. It discusses in detail the interrelationships between the slope transform at one hand and the (Young-Fenchel) conjugate and Legendre transform, two well-known concepts from convex

  17. Internal waves and temperature fronts on slopes

    Directory of Open Access Journals (Sweden)

    S. A. Thorpe

    Full Text Available Time series measurements from an array of temperature miniloggers in a line at constant depth along the sloping boundary of a lake are used to describe the `internal surf zone' where internal waves interact with the sloping boundary. More small positive temperature time derivatives are recorded than negative, but there are more large negative values than positive, giving the overall distribution of temperature time derivatives a small negative skewness. This is consistent with the internal wave dynamics; fronts form during the up-slope phase of the motion, bringing cold water up the slope, and the return flow may become unstable, leading to small advecting billows and weak warm fronts. The data are analysed to detect `events', periods in which the temperature derivatives exceed a set threshold. The speed and distance travelled by `events' are described. The motion along the slope may be a consequence of (a instabilities advected by the flow (b internal waves propagating along-slope or (c internal waves approaching the slope from oblique directions. The propagation of several of the observed 'events' can only be explained by (c, evidence that the internal surf zone has some, but possibly not all, the characteristics of the conventional 'surface wave' surf zone, with waves steepening as they approach the slope at oblique angles.

    Key words. Oceanography: general (benthic boundary layers; limnology, Oceanography: physical (internal and inertial waves

  18. Visual attention in posterior stroke

    DEFF Research Database (Denmark)

    Fabricius, Charlotte; Petersen, Anders; Iversen, Helle K

    Objective: Impaired visual attention is common following strokes in the territory of the middle cerebral artery, particularly in the right hemisphere. However, attentional effects of more posterior lesions are less clear. The aim of this study was to characterize visual processing speed...... and apprehension span following posterior cerebral artery (PCA) stroke. We also relate these attentional parameters to visual word recognition, as previous studies have suggested that reduced visual speed and span may explain pure alexia. Methods: Nine patients with MR-verified focal lesions in the PCA......-territory (four left PCA; four right PCA; one bilateral, all >1 year post stroke) were compared to 25 controls using single case statistics. Visual attention was characterized by a whole report paradigm allowing for hemifield-specific speed and span measurements. We also characterized visual field defects...

  19. Classification of posterior vitreous detachment

    OpenAIRE

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2013-01-01

    Akihiro Kakehashi,1 Mikiko Takezawa,1 Jun Akiba21Department of Ophthalmology, Jichi Medical University, Saitama Medical Center, Saitama, 2Kanjodori Eye Clinic, Asahikawa, JapanAbstract: Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography...

  20. Posterior reversible encephalopathy syndrome in the emergency ...

    African Journals Online (AJOL)

    Posterior reversible encephalopathy syndrome in the emergency service. ... The most common etiologies of PRES are hypertension and renal failure, and the most frequent pathophysiology is hyperperfusion. PRES is ... Keywords: Emergency service, hyperperfusion, posterior reversible encephalopathy, vasogenic edema ...

  1. Factors affecting seismic response of submarine slopes

    Directory of Open Access Journals (Sweden)

    G. Biscontin

    2006-01-01

    Full Text Available The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and 'local' tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.

  2. Wave run-up on sandbag slopes

    Directory of Open Access Journals (Sweden)

    Thamnoon Rasmeemasmuang

    2014-03-01

    Full Text Available On occasions, sandbag revetments are temporarily applied to armour sandy beaches from erosion. Nevertheless, an empirical formula to determine the wave run -up height on sandbag slopes has not been available heretofore. In this study a wave run-up formula which considers the roughness of slope surfaces is proposed for the case of sandbag slopes. A series of laboratory experiments on the wave run -up on smooth slopes and sandbag slopes were conducted in a regular-wave flume, leading to the finding of empirical parameters for the formula. The proposed empirical formula is applicable to wave steepness ranging from 0.01 to 0.14 and to the thickness of placed sandbags relative to the wave height ranging from 0.17 to 3.0. The study shows that the wave run-up height computed by the formula for the sandbag slopes is 26-40% lower than that computed by the formula for the smooth slopes.

  3. MECHANICAL HARVESTING OF COFFEE IN HIGH SLOPE

    Directory of Open Access Journals (Sweden)

    FELIPE SANTINATO

    2016-01-01

    Full Text Available Brazilian coffee farming is carried out both on flat and steep lands. In flat areas, mechanized operations are intensive; however, in steep slope areas, certain mechanized operations cannot be performed, such as harvesting. Based on this, the industry has developed machinery to harvest coffee in areas with up to 30% slope. However, harvesters have their efficiency and operational performance influenced by land slope. Thus, this study aimed to evaluate the operational performance and harvesting efficiency of a steep-slope harvester under different situations, using different speed settings. The experiment was carried out in the county of Santo Antônio do Amparo, state of Minas Gerais, Brazil, using five coffee stands with 10, 15, 20, 25 and 30% slope. Evaluations were performed with a self-propelled harvester (Electron, TDI®, Araguari, MG, Brazil at three rotation speeds (600, 800 and 1.000 rpm and two ground speeds (800 and 1.000 m h-1. The results showed the lower speed (800 m h-1 was suitable for 10% slope areas since the amount of fallen coffee berries. For areas of 20% slope, harvesting time was 21.6% longer than in flatter areas. Downtime varied from 10.66 to 29.18% total harvest due to a higher number of maneuvers.

  4. Low-velocity impact cratering experiments in granular slopes

    Science.gov (United States)

    Hayashi, Kosuke; Sumita, Ikuro

    2017-07-01

    Low-velocity impact cratering experiments are conducted in sloped granular targets to study the effect of the slope angle θ on the crater shape and its scales. We use two types of granular matter, sand and glass beads, former of which has a larger friction coefficient μs = tanθr , where θr is the angle of repose. Experiments show that as θ increases, the crater becomes shallower and elongated in the direction of the slope. Furthermore the crater floor steepens in the upslope side and a thick rim forms in the downslope side, thus forming an asymmetric profile. High-speed images show that these features are results of ejecta being dispersed farther towards the downslope side and the subsequent avalanche which buries much of the crater floor. Such asymmetric ejecta dispersal can be explained by combining the Z-model and a ballistic model. Using the topographic maps of the craters, we classify crater shape regimes I-III, which transition with increasing θ : a full-rim crater (I), a broken-rim crater (II), and a depression (III). The critical θ for the regime transitions are larger for sand compared to glass beads, but collapse to close values when we use a normalized slope θ^ = tanθ / tanθr . Similarly we derive θ^-dependences of the scaled crater depth, length, width and their ratios which collapse the results for different targets and impact energies. We compare the crater profiles formed in our experiments with deep craters on asteroid Vesta and find that some of the scaled profiles nearly overlap and many have similar depth / length ratios. This suggests that these Vestan craters may also have formed in the gravity regime and that the formation process can be approximated by a granular flow with a similar effective friction coefficient.

  5. Rock Slope Design Criteria : Executive Summary Report

    Science.gov (United States)

    2010-06-01

    Based on the stratigraphy and the type of slope stability problems, the flat lying, Paleozoic age, sedimentary rocks of Ohio were divided into three design units: 1) competent rock design unit consisting of sandstones, limestones, and siltstones that...

  6. Slope activity in Gale crater, Mars

    Science.gov (United States)

    Dundas, Colin M.; McEwen, Alfred S.

    2015-01-01

    High-resolution repeat imaging of Aeolis Mons, the central mound in Gale crater, reveals active slope processes within tens of kilometers of the Curiosity rover. At one location near the base of northeastern Aeolis Mons, dozens of transient narrow lineae were observed, resembling features (Recurring Slope Lineae) that are potentially due to liquid water. However, the lineae faded and have not recurred in subsequent Mars years. Other small-scale slope activity is common, but has different spatial and temporal characteristics. We have not identified confirmed RSL, which Rummel et al. (Rummel, J.D. et al. [2014]. Astrobiology 14, 887–968) recommended be treated as potential special regions for planetary protection. Repeat images acquired as Curiosity approaches the base of Aeolis Mons could detect changes due to active slope processes, which could enable the rover to examine recently exposed material.

  7. Slope failure investigation management system : [research summary].

    Science.gov (United States)

    2013-03-01

    Highway slopes are exposed to a variety of environmental and climatic conditions, : such as deforestation, cycles of freezing and thawing weather, and heavy storms. : Over time, these climatic conditions, in combination with other factors such as : g...

  8. Percent Agricultural Land Cover on Steep Slopes

    Data.gov (United States)

    U.S. Environmental Protection Agency — Clearing land for agriculture tends to increase soil erosion. The amount of erosion is related to the steepness of the slope, farming methods used and soil type....

  9. North Slope, Alaska ESI: BIRDS (Bird Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for diving birds, gulls and terns, seabirds, shorebirds, and waterfowl for the North Slope of Alaska....

  10. Green technologies for reducing slope erosion.

    Science.gov (United States)

    2010-01-01

    As climate change alters precipitation patterns, departments of transportation will increasingly face the problem of : slope failures, which already cost California millions of dollars in repair work annually. Caltrans hopes to prevent : these failur...

  11. North Slope, Alaska ESI: FISH (Fish Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for marine, estuarine, anadromous, and freshwater fish species for the North Slope of Alaska. Vector...

  12. 3D geodetic monitoring slope deformations

    Directory of Open Access Journals (Sweden)

    Weiss Gabriel

    1996-06-01

    Full Text Available For plenty of slope failures that can be found in Slovakia is necessary and very important their geodetic monitoring (because of their activity, reactivisations, checks. The paper gives new methodologies for these works, using 3D terrestrial survey technologies for measurements in convenient deformation networks. The design of an optimal type of deformation model for various kinds of landslides and their exact processing with an efficient testing procedure to determine the kinematics of the slope deformations are presented too.

  13. Huge interparietal posterior fontanel meningohydroencephalocele

    OpenAIRE

    Jorge Félix Companioni Rosildo; Manuel Filipe Dias dos Santos; Rita de Cassia de Santa Barbara

    2015-01-01

    Congenital encephalocele is a neural tube defect characterized by a sac-like protrusion of the brain, meninges, and other intracranial structures through the skull, which is caused by an embryonic development abnormality. The most common location is at the occipital bone, and its incidence varies according to different world regions. We report a case of an 1-month and 7-day-old male child with a huge interparietal-posterior fontanel meningohydroencephalocele, a rare occurrence. Physical exami...

  14. Can the human lumbar posterior columns be stimulated by transcutaneous spinal cord stimulation? A modeling study.

    Science.gov (United States)

    Danner, Simon M; Hofstoetter, Ursula S; Ladenbauer, Josef; Rattay, Frank; Minassian, Karen

    2011-03-01

    Stimulation of different spinal cord segments in humans is a widely developed clinical practice for modification of pain, altered sensation, and movement. The human lumbar cord has become a target for modification of motor control by epidural and, more recently, by transcutaneous spinal cord stimulation. Posterior columns of the lumbar spinal cord represent a vertical system of axons and when activated can add other inputs to the motor control of the spinal cord than stimulated posterior roots. We used a detailed three-dimensional volume conductor model of the torso and the McIntyre-Richard-Grill axon model to calculate the thresholds of axons within the posterior columns in response to transcutaneous lumbar spinal cord stimulation. Superficially located large-diameter posterior column fibers with multiple collaterals have a threshold of 45.4 V, three times higher than posterior root fibers (14.1 V). With the stimulation strength needed to activate posterior column axons, posterior root fibers of large and small diameters as well as anterior root fibers are coactivated. The reported results inform on these threshold differences, when stimulation is applied to the posterior structures of the lumbar cord at intensities above the threshold of large-diameter posterior root fibers. © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  15. Numerical Computation of Homogeneous Slope Stability

    Directory of Open Access Journals (Sweden)

    Shuangshuang Xiao

    2015-01-01

    Full Text Available To simplify the computational process of homogeneous slope stability, improve computational accuracy, and find multiple potential slip surfaces of a complex geometric slope, this study utilized the limit equilibrium method to derive expression equations of overall and partial factors of safety. This study transformed the solution of the minimum factor of safety (FOS to solving of a constrained nonlinear programming problem and applied an exhaustive method (EM and particle swarm optimization algorithm (PSO to this problem. In simple slope examples, the computational results using an EM and PSO were close to those obtained using other methods. Compared to the EM, the PSO had a small computation error and a significantly shorter computation time. As a result, the PSO could precisely calculate the slope FOS with high efficiency. The example of the multistage slope analysis indicated that this slope had two potential slip surfaces. The factors of safety were 1.1182 and 1.1560, respectively. The differences between these and the minimum FOS (1.0759 were small, but the positions of the slip surfaces were completely different than the critical slip surface (CSS.

  16. Seasonal slope surface deformation measured with TLS

    International Nuclear Information System (INIS)

    Fan, L; Smethurst, J; Powrie, W; Sellaiya, A

    2014-01-01

    In temperate European climates, soil water removal due to vegetation transpiration peaks in summer and soil rewetting from higher levels of precipitation occurs in winter. In clays of high plasticity, the seasonal cycles of drying and wetting cause the soil to experience a volumetric change, resulting in seasonal shrinking and swelling. For a clay slope exhibiting volume change, such behaviour can lead to excessive deformation and could contribute to strain-softening and progressive slope failure. This can in turn cause traffic disruption and loss of life if roads and railways are founded on or surrounded by such slopes. This paper discusses the driving forces of seasonal surface movement, in particular the role of vegetation, and presents the use of Terrestrial Laser Scanning (TLS) to measure the surface movement of a lightly vegetated London Clay slope near Newbury, UK. Two TLS scans were carried out in early and late summer respectively, representing relative wet and dry conditions of the slope. Continuous field measurements of soil water content in upper layers of the slope were obtained from TDR ThetaProbes already installed at the site. The water content data are used to support the results obtained from TLS by indicating the likely volumetric change in the soil due to loss of water

  17. Automatic approach to deriving fuzzy slope positions

    Science.gov (United States)

    Zhu, Liang-Jun; Zhu, A.-Xing; Qin, Cheng-Zhi; Liu, Jun-Zhi

    2018-03-01

    Fuzzy characterization of slope positions is important for geographic modeling. Most of the existing fuzzy classification-based methods for fuzzy characterization require extensive user intervention in data preparation and parameter setting, which is tedious and time-consuming. This paper presents an automatic approach to overcoming these limitations in the prototype-based inference method for deriving fuzzy membership value (or similarity) to slope positions. The key contribution is a procedure for finding the typical locations and setting the fuzzy inference parameters for each slope position type. Instead of being determined totally by users in the prototype-based inference method, in the proposed approach the typical locations and fuzzy inference parameters for each slope position type are automatically determined by a rule set based on prior domain knowledge and the frequency distributions of topographic attributes. Furthermore, the preparation of topographic attributes (e.g., slope gradient, curvature, and relative position index) is automated, so the proposed automatic approach has only one necessary input, i.e., the gridded digital elevation model of the study area. All compute-intensive algorithms in the proposed approach were speeded up by parallel computing. Two study cases were provided to demonstrate that this approach can properly, conveniently and quickly derive the fuzzy slope positions.

  18. Increase in the Tibial Slope Reduces Wear after Medial Unicompartmental Fixed-Bearing Arthroplasty of the Knee

    Directory of Open Access Journals (Sweden)

    Patrick Weber

    2015-01-01

    Full Text Available Introduction. Unicompartmental arthroplasty of the knee in patients with isolated medial osteoarthritis gives good results, but survival is inferior to that of total knee prosthesis. Knees may fail because positioning of the prosthesis has been suboptimal. The aim of this study was to investigate the influence of the tibial slope on the rate of wear of a medial fixed-bearing unicompartmental knee arthroplasty. Materials and Methods. We simulated wear on a medial fixed-bearing unicompartmental knee prosthesis (Univation in vitro with a customised, four-station, and servohydraulic knee wear simulator, which exactly reproduced the walking cycle (International Organisation for Standardisation (ISO 14243-1:2002(E. The medial prostheses were inserted with 3 different posterior tibial slopes: 0°, 4°, and 8° (n = 3 in each group. Results. The wear rate decreased significantly between 0° and 4° slope from 10.4 (SD 0.62 mg/million cycles to 3.22 (SD 1.71 mg/million cycles. Increasing the tibial slope to 8° did not significantly change the wear rate. Discussion. As an increase in the tibial slope reduced the wear rate in a fixed-bearing prosthesis, a higher tibial slope should be recommended. However, other factors that are influenced by the tibial slope (e.g., the tension of the ligament must also be considered.

  19. Huge interparietal posterior fontanel meningohydroencephalocele

    Directory of Open Access Journals (Sweden)

    Jorge Félix Companioni Rosildo

    2015-03-01

    Full Text Available Congenital encephalocele is a neural tube defect characterized by a sac-like protrusion of the brain, meninges, and other intracranial structures through the skull, which is caused by an embryonic development abnormality. The most common location is at the occipital bone, and its incidence varies according to different world regions. We report a case of an 1-month and 7-day-old male child with a huge interparietal-posterior fontanel meningohydroencephalocele, a rare occurrence. Physical examination and volumetric computed tomography were diagnostic. The encephalocele was surgically resected. Intradural and extradural approaches were performed; the bone defect was not primarily closed. Two days after surgery, the patient developed hydrocephaly requiring ventriculoperitoneal shunting. The surgical treatment of the meningohydroencephalocele of the interparietal-posterior fontanel may be accompanied by technical challenges and followed by complications due to the presence of large blood vessels under the overlying skin. In these cases, huge sacs herniate through large bone defects including meninges, brain, and blood vessels. The latter present communication with the superior sagittal sinus and ventricular system. A favorable surgical outcome generally follows an accurate strategy taking into account individual features of the lesion.

  20. Sloping fan travertine, Belen, New Mexico, USA

    Science.gov (United States)

    Cook, Megan; Chafetz, Henry S.

    2017-05-01

    Pliocene to Quaternary age travertines are very well-exposed in quarries near Belen, New Mexico, U.S.A., on the western edge of the Rio Grande Rift system. A series of hillside springs produced travertine tongues tens of meters thick and hundreds of meters long. The accumulations represent deposits from individual springs as well as the amalgamation of deposits. The overall architecture is predominantly composed of sloping fans with a smaller component of terrace mounds. The sloping fan deposits commonly have a dip of step morphology. As a consequence of vertical accretion in the pools, terrace mounds morphed into sloping fans. The travertine is composed of a variety of commonly reported constituents, i.e., centimeter thick laminae of bacterial shrubs and oncoids, foam rock, sheets and rafts, and finely crystalline crusts that occur throughout the sloping fan and terrace mound accumulations. Sheets and rafts formed as precipitates in pools on the surfaces of the fans and terraces as well as spelean deposits on the water surfaces of pools within cavities in the overall accumulation. Thus, the spelean rafts provide valuable indicators of original horizontality in the sloping fan strata. In addition, intraformational breccias, composed of locally torn-up travertine intraclastic boulders and deposited in with other travertine, and extraformational breccias, composed of torn-up travertine intraclasts mixed with siliciclastic fines and sand and Paleozoic limestone clasts transported downslope from higher on the hillside, are a common constituent in the sloping fan accumulation. The Belen travertines provide a very well-exposed example of sloping fan travertines and may provide relevant data with regard to the subsurface Aptian Pre-Salt deposits, offshore Brazil.

  1. Exploring the brain through posterior hypothalamus surgery for aggressive behavior.

    Science.gov (United States)

    Rizzi, Michele; Trezza, Andrea; Messina, Giuseppe; De Benedictis, Alessandro; Franzini, Angelo; Marras, Carlo Efisio

    2017-09-01

    Neurological surgery offers an opportunity to study brain functions, through either resection or implanted neuromodulation devices. Pathological aggressive behavior in patients with intellectual disability is a frequent condition that is difficult to treat using either supportive care or pharmacological therapy. The bulk of the laboratory studies performed throughout the 19th century enabled the formulation of hypotheses on brain circuits involved in the generation of emotions. Aggressive behavior was also studied extensively. Lesional radiofrequency surgery of the posterior hypothalamus, which peaked in the 1970s, was shown to be an effective therapy in many reported series. As with other surgical procedures for the treatment of psychiatric disorders, however, this therapy was abandoned for many reasons, including the risk of its misuse. Deep brain stimulation (DBS) offers the possibility of treating neurological and psychoaffective disorders through relatively reversible and adaptable therapy. Deep brain stimulation of the posterior hypothalamus was proposed and performed successfully in 2005 as a treatment for aggressive behavior. Other groups reported positive outcomes using target and parameter settings similar to those of the original study. Both the lesional and DBS approaches enabled researchers to explore the role of the posterior hypothalamus (or posterior hypothalamic area) in the autonomic and emotional systems.

  2. Decision Guide for Roof Slope Selection

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, T.R.

    1988-01-01

    This decision guide has been written for personnel who are responsible for the design, construction, and replacement of Air Force roofs. It provides the necessary information and analytical tools for making prudent and cost-effective decisions regarding the amount of slope to provide in various roofing situations. Because the expertise and experience of the decision makers will vary, the guide contains both basic slope-related concepts as well as more sophisticated technical data. This breadth of information enables the less experienced user to develop an understanding of roof slope issues before applying the more sophisticated analytical tools, while the experienced user can proceed directly to the technical sections. Although much of this guide is devoted to the analysis of costs, it is not a cost-estimating document. It does, however, provide the reader with the relative costs of a variety of roof slope options; and it shows how to determine the relative cost-effectiveness of different options. The selection of the proper roof slope coupled with good roof design, a quality installation, periodic inspection, and appropriate maintenance and repair will achieve the Air Force's objective of obtaining the best possible roofing value for its buildings.

  3. Role of slope on infiltration: A review

    Science.gov (United States)

    Morbidelli, Renato; Saltalippi, Carla; Flammini, Alessia; Govindaraju, Rao S.

    2018-02-01

    Partitioning of rainfall at the soil-atmosphere interface is important for both surface and subsurface hydrology, and influences many events of major hydrologic interest such as runoff generation, aquifer recharge, and transport of pollutants in surface waters as well as the vadose zone. This partitioning is achieved through the process of infiltration that has been widely investigated at the local scale, and more recently also at the field scale, by models that were designed for horizontal surfaces. However, infiltration, overland flows, and deep flows in most real situations are generated by rainfall over sloping surfaces that bring in additional effects. Therefore, existing models for local infiltration into homogeneous and layered soils and those as for field-scale infiltration, have to be adapted to account for the effects of surface slope. Various studies have investigated the role of surface slope on infiltration based on a theoretical formulations for the dynamics of infiltration, extensions of the Green-Ampt approach, and from laboratory and field experiments. However, conflicting results have been reported in the scientific literature on the role of surface slope on infiltration. We summarize the salient points from previous studies and provide plausible reasons for discrepancies in conclusions of previous authors, thus leading to a critical assessment of the current state of our understanding on this subject. We offer suggestions for future efforts to advance our knowledge of infiltration over sloping surfaces.

  4. Winter chemistry of North Slope lakes

    Science.gov (United States)

    Chambers, M. K.; White, D. M.; Lilly, M. R.; Hinzman, L. D.; Hilton, K. M.; Busey, R.

    2006-12-01

    Lakes are important water resources on the North Slope of Alaska. Oilfield exploration and production requires water for facility use as well as transportation. Ice road construction requires winter extraction of fresh water. Since most North Slope lakes are relatively shallow, the quantity and quality of the water remaining under the ice by the end of the winter are important environmental management issues. Currently permits are based on the presence of overwintering fish populations and their sensitivity to low oxygen. Sampling during the winter of 2004 2005 sheds light on the winter chemistry of several pumped lakes and one unpumped lake on the North Slope. Dissolved oxygen, conductivity, pH, and temperature profiles were taken along with ice thickness and water depth measurements. Water samples were extracted and analyzed for Na, Ca, K, Mg, Fe, DOC, and alkalinity in the laboratory. Lake properties, rather than pumping activities, were the best predictors of oxygen depletion, with the highest levels of dissolved oxygen maintained in the lake with the least dissolved constituents. As would be expected, specific conductance increased with depth in the lake while dissolved oxygen decreased with depth. Dissolved oxygen and specific conductance data suggested that the lakes began to refresh in May. The summarized data provides a view of North Slope lake chemistry trends, while continued studies investigate the chemical impacts of pumping North Slope lakes through continued sampling and modeling efforts.

  5. Posterior ankle impingement in the dancer.

    Science.gov (United States)

    Moser, Brad R

    2011-01-01

    Dancers spend a lot of time in the relevé position in demi-pointe and en pointe in their training and their careers. Pain from both osseous and soft tissue causes may start to occur in the posterior aspect of their ankle. This article reviews the potential causes of posterior ankle impingement in dancers. It will discuss the clinical evaluation of a dancer and the appropriate workup and radiographic studies needed to further evaluate a dancer with suspected posterior ankle impingement.

  6. Pterygoid implant for atrophic posterior maxilla

    Directory of Open Access Journals (Sweden)

    V R Balaji

    2017-01-01

    Full Text Available Replacement of missing teeth in the posterior maxilla is always a challenge for the treating implant surgeon as the posterior maxilla has several obstacles in the form of quality, quantity, the anatomy of the maxillary sinus, and inaccessibility. To overcome these deficiencies, several surgical procedures such as sinus lift, bone augmentation, tilted implants, short implants, and zygomatic implants were tried. Since these procedures have their own limitations, pterygomaxillary region provides us an excellent place for placement of implant and rehabilitation of posterior maxilla. This case report describes the usage of the pterygomaxillary region for placement of the implant to restore atrophic posterior maxilla, without any additional surgical procedures.

  7. Centrifuge model test of rock slope failure caused by seismic excitation. Plane failure of dip slope

    International Nuclear Information System (INIS)

    Ishimaru, Makoto; Kawai, Tadashi

    2008-01-01

    Recently, it is necessary to assess quantitatively seismic safety of critical facilities against the earthquake induced rock slope failure from the viewpoint of seismic PSA. Under these circumstances, it is essential to evaluate more accurately the possibilities of rock slope failure and the potential failure boundary, which are triggered by earthquake ground motions. The purpose of this study is to analyze dynamic failure characteristics of rock slopes by centrifuge model tests for verification and improvement of the analytical methods. We conducted a centrifuge model test using a dip slope model with discontinuities limitated by Teflon sheets. The centrifugal acceleration was 50G, and the acceleration amplitude of input sin waves increased gradually at every step. The test results were compared with safety factors of the stability analysis based on the limit equilibrium concept. Resultant conclusions are mainly as follows: (1) The slope model collapsed when it was excited by the sine wave of 400gal, which was converted to real field scale, (2) Artificial discontinuities were considerably concerned in the collapse, and the type of collapse was plane failure, (3) From response acceleration records observed at the slope model, we can say that tension cracks were generated near the top of the slope model during excitation, and that might be cause of the collapse, (4) By considering generation of the tension cracks in the stability analysis, correspondence of the analytical results and the experimental results improved. From the obtained results, we need to consider progressive failure in evaluating earthquake induced rock slope failure. (author)

  8. Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

    2009-09-16

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.

  9. Modern Slope Processes on the Moon

    Science.gov (United States)

    Shevchenko, V. V.; Pine, P. K.; Shevrel, S. D.; Dadu, I.; Lu, Y.; Skobeleva, T. P.; Kvaratskhelia, O.; Rosemberg, K.

    2012-01-01

    Slope movements of material in lunar craters are investigated based on remote spectral studies carried out on board the Clementine spacecraft, and data obtained during the large-scale survey on board the LRO (Lunar Reconnaissance Orbit) spacecraft. The morphological analysis of crater forms based on large-scale images and spectral and spectropolarized assessments of the exposition age (or maturity) of the slope material has led to the conclusion that the formation process of observed outcrops probably is a modern feature. The lower age limit of these structures is estimated at 40-80 years. Thus, slope movements of surface materials can continue at the present time, regardless of the age of the crater studied. Slope movements of crushed granular material lead to fresh outcrops of subsurface layers of marine or continental landscapes and, therefore, extend our capabilities to research the deep material of the Moon. To analyze this phenomenon, craters of 16 and 30 km have been selected. The length of fresh outcrops, while depending strongly on the dimensions of the craters, can be up to several kilometers. In connection with this, the prospect appears of remote analysis of rocks that came to the surface from depths of at least several hundred meters. In this case, there are openings for the contact analysis of subsurface material without the use of labor-intensive operations associated with the delivery of equipment for deep drilling to the lunar surface.

  10. Interrill soil erosion processes on steep slopes

    Science.gov (United States)

    To date interrill erosion processes and regimes are not fully understood. The objectives are to 1) identify the erosion regimes and limiting processes between detachment and transport on steep slopes, 2) characterize the interactive effects between rainfall intensity and flow depth on sediment trans...

  11. Mathematics, Physics and Computer Sciences Dual slope ...

    African Journals Online (AJOL)

    Mathematics, Physics and Computer Sciences Dual slope integration technique to design a digital thermometer. S. F. AKANDE, E. D. DADOEM. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/gjpas.v7i2.16256 · AJOL African Journals Online.

  12. VT USGS NED Slope (10 meter) - statewide

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) Used ElevationDEM_DEM10M and the Arc/Info SLOPE command with the "PERCENT_RISE" and ".3048" Z_unit options to create this data layer. Input source...

  13. A Worthwhile Task to Teach Slope

    Science.gov (United States)

    Wagener, Lauren L.

    2009-01-01

    Since mathematics is found in every aspect of life, it is important for teachers to provide experiences that help students find connections and develop an appreciation for math and its use in their lives outside school. Slope is an excellent example of a math concept that is usually taught without context or connection. In this article, the…

  14. Fractal Rock Slope Dynamics Anticipating a Collapse

    Czech Academy of Sciences Publication Activity Database

    Paluš, Milan; Novotná, Dagmar; Zvelebil, Jiří

    2004-01-01

    Roč. 70 (2004), 036212 ISSN 1063-651X R&D Projects: GA ČR GA205/00/1055 Institutional research plan: CEZ:AV0Z1030915 Keywords : fractal * scaling * unstable rock slope * collapse prediction * engineering geology Subject RIV: BA - General Mathematics Impact factor: 2.352, year: 2004

  15. A Novel Way To Practice Slope.

    Science.gov (United States)

    Kennedy, Jane B.

    1997-01-01

    Presents examples of using a tic-tac-toe format to practice finding the slope and identifying parallel and perpendicular lines from various equation formats. Reports the successful use of this format as a review in both precalculus and calculus classes before students work with applications of analytic geometry. (JRH)

  16. On Front Slope Stability of Berm Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    2013-01-01

    The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison with the r......The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified (Burcharth, 2008) by comparison...... with the reshaping of a large Norwegian breakwater exposed to the North Sea waves. As a motivation for applying the Van der Meer formula a discussion of design parameters related to berm breakwater stability formulae is given. Comparisons of front erosion predicted by the use of the Van der Meer formula with model...... test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height...

  17. Posterior Surgical Approach to Tuberculous Spondylitis | Shehu ...

    African Journals Online (AJOL)

    Objectives: Foraminotomy is a simple posterior surgical approach useful for treatment of radicular (nerve root) pain in TB spondylitis. It doesn't affect the stability of the facet joint, requires neither fusion nor implants. It is therefore cheap and affordable for patients with low income. We describe a simple form of posterior spinal ...

  18. Cervical disc hernia operations through posterior laminoforaminotomy

    OpenAIRE

    Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

    2016-01-01

    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 ...

  19. Oxymetazoline in the treatment of posterior epistaxis.

    Science.gov (United States)

    Doo, G; Johnson, D S

    1999-08-01

    In this retrospective study, 36 patients were given oxymetazoline as a first step in treatment for posterior epistaxis. In 75% of the cases, epistaxis was effectively treated with oxymetazoline with no recurrent bleeding. All cases with recurrence resolved with continued administration of oxymetazoline. The results of this study propose a pharmacologic intervention for the treatment of posterior epistaxis.

  20. Posterior atlantooccipital subluxation in Down syndrome.

    Science.gov (United States)

    El-Khoury, G Y; Clark, C R; Dietz, F R; Harre, R G; Tozzi, J E; Kathol, M H

    1986-05-01

    Three Down syndrome patients with posterior atlantooccipital (AO) subluxation are described. All are asymptomatic. The subluxation becomes manifest during active extension of the neck and reduces in flexion. Methods of assessing posterior AO subluxation are discussed. The abnormality is attributed to ligamentous laxity in patients with Down syndrome.

  1. Advance in prediction of soil slope instabilities

    Science.gov (United States)

    Sigarán-Loría, C.; Hack, R.; Nieuwenhuis, J. D.

    2012-04-01

    Six generic soils (clays and sands) were systematically modeled with plane-strain finite elements (FE) at varying heights and inclinations. A dataset was generated in order to develop predictive relations of soil slope instabilities, in terms of co-seismic displacements (u), under strong motions with a linear multiple regression. For simplicity, the seismic loads are monochromatic artificial sinusoidal functions at four frequencies: 1, 2, 4, and 6 Hz, and the slope failure criterion used corresponds to near 10% Cartesian shear strains along a continuous region comparable to a slip surface. The generated dataset comprises variables from the slope geometry and site conditions: height, H, inclination, i, shear wave velocity from the upper 30 m, vs30, site period, Ts; as well as the input strong motion: yield acceleration, ay (equal to peak ground acceleration, PGA in this research), frequency, f; and in some cases moment magnitude, M, and Arias intensity, Ia, assumed from empirical correlations. Different datasets or scenarios were created: "Magnitude-independent", "Magnitude-dependent", and "Soil-dependent", and the data was statistically explored and analyzed with varying mathematical forms. Qualitative relations show that the permanent deformations are highly related to the soil class for the clay slopes, but not for the sand slopes. Furthermore, the slope height does not constrain the variability in the co-seismic displacements. The input frequency decreases the variability of the co-seismic displacements for the "Magnitude-dependent" and "Soil-dependent" datasets. The empirical models were developed with two and three predictors. For the sands it was not possible because they could not satisfy the constrains from the statistical method. For the clays, the best models with the smallest errors coincided with the simple general form of multiple regression with three predictors (e.g. near 0.16 and 0.21 standard error, S.E. and 0.75 and 0.55 R2 for the "M

  2. Posterior atlantooccipital membrane for duraplasty. Technical note.

    Science.gov (United States)

    Tubbs, R Shane; Wellons, John C; Blount, Jeffrey P; Oakes, W Jerry

    2002-09-01

    The authors describe the use of autogenetic posterior atlantooccipital (PAO) membrane for duraplasty following after posterior cranial fossa surgery. The PAO membrane is routinely exposed for procedures of the posterior cranial fossa and merely needs to be dissected free of the underlying dura mater. Recently this membrane was obtained in several pediatric patients following procedures of the posterior cranial fossa such as duraplasty in case of Chiari I malformation. No postoperative complications were found at 6-month follow-up examination. The advantages of this intervention include less manipulation of muscle and fascia than that involved in other procedures and, therefore, seemingly less postoperative pain and the negation of issues inherent with foreign-body graft sources. The authors believe this structure to be of use as a dural substitute in small dural openings of the posterior cranial fossa.

  3. Congenital basis of posterior fossa anomalies

    Science.gov (United States)

    Cotes, Claudia; Bonfante, Eliana; Lazor, Jillian; Jadhav, Siddharth; Caldas, Maria; Swischuk, Leonard

    2015-01-01

    The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies. PMID:26246090

  4. Treatment implications of posterior fossa ependymoma subgroups.

    Science.gov (United States)

    Ramaswamy, Vijay; Taylor, Michael D

    2016-11-15

    Posterior fossa ependymoma comprises two distinct molecular entities, ependymoma_posterior fossa A (EPN_PFA) and ependymoma_posterior fossa B (EPN_PFB), with differentiable gene expression profiles. As yet, the response of the two entities to treatment is unclear. To determine the relationship between the two molecular subgroups of posterior fossa ependymoma and treatment, we studied a cohort of 820 patients with molecularly profiled, clinically annotated posterior fossa ependymomas. We found that the strongest predictor of poor outcome in patients with posterior fossa ependymoma across the entire age spectrum was molecular subgroup EPN_PFA, which was recently reported in the paper entitled "Therapeutic impact of cytoreductive surgery and irradiation of posterior fossa ependymoma in the molecular era: a retrospective multicohort analysis" in the Journal of Clinical Oncology. Patients with incompletely resected EPN_PFA tumors had a very poor outcome despite receiving adjuvant radiation therapy, whereas a substantial proportion of patients with EPN_PFB tumors can be cured with surgery alone.

  5. The effects of slope length and slope gradient on the size distributions of loess slides: Field observations and simulations

    Science.gov (United States)

    Qiu, Haijun; Cui, Peng; Regmi, Amar Deep; Hu, Sheng; Wang, Xingang; Zhang, Yuzhu

    2018-01-01

    In this study, we characterize and consider the effects of slope length and slope gradient on the size distributions of loess slides. To carry out this study, we employ data on 275 loess slides within Zhidan County, Central Loess Plateau, China. These data were collected in the field and supplemented by the interpretation of remote sensing images. Both the field observations and slope stability analysis show that loess slide size increases with the slope length. Slide sizes is significantly correlated with slope length, showing a power law relationship in both cases. However, the simulation results show that slope gradient is not associated with loess slide size. The main part of the link between slope gradient and slide size seen in the observations is only apparent, as indicated by the strong connection between slope gradient and length. Statistical analysis of the field observations reveals that slope gradient decreases with increasing slope length, and this correlation interferes with the potential relationship between landslide sizes and slope gradient seen in the field observations. In addition, the probability densities of the areas of loess slides occurring on slopes of different slope lengths are determined using kernel density estimation. This analysis shows that slope length controls the rollover of the frequency-size distribution of loess slides. The scaling exponent increases with slope length.

  6. Microsurgical management of posterior circulation aneurysms

    Directory of Open Access Journals (Sweden)

    SHI Xiang-en

    2012-02-01

    Full Text Available Objective To retrospectively analyze effective methods for surgical management of posterior circulation aneurysms. Methods There were 42 patients with posterior circulation aneurysms [26 cases of basilar aneurysm (27 aneurysms, 16 cases of vertebral aneurysm (17 aneurysms]. There were 15 patients underwent bypass surgery [4 external carotid artery-P2 segment of posterior cerebral artery (ECA-P2, 2 internal carotid artery-P2 segment of posterior cerebral artery (ICA-P2, 2 internal maxillary artery-P2 segment of posterior cerebral artery (IMA-P2, 2 intracranial segment of vertebral artery-extracranial segment of vertebral artery, 5 occipital artery-posterior inferior cerebellar artery (OA-PICA] and 27 patients underwent simple surgical clipping. Results Activities of daily life of 37 patients recovered to normal (14 patients with aneurysm on the top of basilar artery, 3 with aneurysm on the trunk of basilar artery, 9 with vertebral aneurysm, 5 with posterior inferior cerebellar artery aneurysm, 4 with aneurysm on the junction of P1-P2 segment of posterior cerebral artery, 1 with superior cerebellar artery, and 1 with anterior inferior cerebellar aneurysm. None of them occurred operation-related neurological dysfunction. The recovery rate was 88.09% . Among the other patients, 1 with aneurysm on the top of basilar artery presented severe signs and symptoms of neurological defect and cannot take care of oneself, 2 patients (1 with aneurysm on the top of basilar artery, 1 with aneurysm on the trunk of basilar artery occurred brain stem hemorrhage after operation, and died at perioperative period, 2 with vertebral aneurysm relapsed and was cured after treatment. Conclusion Posterior circulation aneurysm which is not suitable for surgical clipping can be treated with intra? and extra?cranial vessel bypass. It may avoid the risk of surgical clipping of aneurysm.

  7. Wildlife response on the Alaska North Slope

    International Nuclear Information System (INIS)

    Costanzo, D.; McKenzie, B.

    1992-01-01

    Recognizing the need for a comprehensive plan to deal with potentially oiled wildlife on the Alaskan North Slope, a multifaceted wildlife protection strategy was developed and implemented during 1991. The strategy incorporated all aspects of wildlife response including protection of critical habitat, hazing, capture and stabilization, long term rehabilitation, and release. The primary wildlife response strategy emphasizes controlling of the release and spreading of spilled oil at the source to prevent or reduce contamination of potentially affected species and/or their habitat. A secondary response strategy concentrates on keeping potentially affected wildlife away from an oiled area through the use of deterrent techniques. Tertiary response involves the capture and treatment of oiled wildlife. Implementation of the strategy included the development of specialized training, the procurement of equipment, and the construction of a bird stabilization center. The result of this initiative is a comprehensive wildlife response capability on the Alaskan North Slope. 1 ref., 5 figs., 3 tabs

  8. Slope parameters of ππ-system

    International Nuclear Information System (INIS)

    Isaev, P.S.; Osipov, A.A.

    1984-01-01

    The slope parameters of the ππ-system are calculated in the framework of the superconductor-tupe quark model. The analogous calculations are made for πK-system. The amplitudes are obtained by using the box quark diagrams and tree diagrams with the intermediate scalar epsilon(700), Ssup(x)(975), K tilde (1350) mesons and vector rho(770), K* (892) mesons

  9. Interrill soil erosion processes on steep slopes

    Science.gov (United States)

    Zhang, X. C. (John); Wang, Z. L.

    2017-05-01

    To date interrill erosion processes are not fully understood under different rainfall and soil conditions. The objectives are to 1) identify the interrill erosion regime and limiting process under the study condition, 2) characterize the interactive effects of rainfall intensity and flow depth on sediment transport competency and mode, and 3) develop a lumped interrill erosion model. A loess loam soil with 39% sand and 45% silt was packed to flumes and exposed to simulated rainfall. A complete factorial design with three factors was used, which included rainfall intensity (48, 62, 102, 149, and 170 mm h-1), slope gradient (17.6, 26.8, 36.4, 46.6, and 57.7%), and slope length (0.4, 0.8, 1.2, 1.6, and 2 m). Rain splash, sediment discharge in runoff, and flow velocity were measured. Results showed that rainfall intensity played a dual role not only in detaching soil materials but also in enhancing sediment transport. Sediment transport was the process limiting interrill erosion rate under the study condition. Two major sediment transport modes were identified: rainfall-driven rolling/creeping and flow-driven rolling/sliding. The relative importance of each mode was largely determined by flow depth. The competence of the flow in transporting sediment decreased downslope as flow depth increased due to increased dissipation of raindrop energy. The optimal mean flow depth for the maximal interrill erosion rates was erosion rate. The negative correlation seemed stronger for heavier rains, indicating the cushioning effects of flow depth. Lumped interrill erosion models, developed from short slopes, are likely to overestimate erosion rates. Given transport as the limiting process, the so called erodibility value, estimated with those models, is indeed sediment transportability under the study condition. The effects of slope length on interrill erosion regimes need to be studied further under a wider range of conditions.

  10. The sloping land conversion program in China

    DEFF Research Database (Denmark)

    Liu, Zhen; Lan, Jing

    2015-01-01

    Through addressing the motivations behind rural households’ livelihood diversification, this paper examines the effect of the Sloping Land Conversion Program (SLCP) on livelihood diversification using a longitudinal household survey data set spanning the overall implementation of the SLCP. Our...... results show that the SLCP works as a valid external policy intervention to increase rural livelihood diversification. In addition, the findings demonstrate that the implementation of the SLCP has had heterogeneous effects on livelihood diversification across different rural income groups. The lower...

  11. Ocean processes at the Antarctic continental slope.

    Science.gov (United States)

    Heywood, Karen J; Schmidtko, Sunke; Heuzé, Céline; Kaiser, Jan; Jickells, Timothy D; Queste, Bastien Y; Stevens, David P; Wadley, Martin; Thompson, Andrew F; Fielding, Sophie; Guihen, Damien; Creed, Elizabeth; Ridley, Jeff K; Smith, Walker

    2014-07-13

    The Antarctic continental shelves and slopes occupy relatively small areas, but, nevertheless, are important for global climate, biogeochemical cycling and ecosystem functioning. Processes of water mass transformation through sea ice formation/melting and ocean-atmosphere interaction are key to the formation of deep and bottom waters as well as determining the heat flux beneath ice shelves. Climate models, however, struggle to capture these physical processes and are unable to reproduce water mass properties of the region. Dynamics at the continental slope are key for correctly modelling climate, yet their small spatial scale presents challenges both for ocean modelling and for observational studies. Cross-slope exchange processes are also vital for the flux of nutrients such as iron from the continental shelf into the mixed layer of the Southern Ocean. An iron-cycling model embedded in an eddy-permitting ocean model reveals the importance of sedimentary iron in fertilizing parts of the Southern Ocean. Ocean gliders play a key role in improving our ability to observe and understand these small-scale processes at the continental shelf break. The Gliders: Excellent New Tools for Observing the Ocean (GENTOO) project deployed three Seagliders for up to two months in early 2012 to sample the water to the east of the Antarctic Peninsula in unprecedented temporal and spatial detail. The glider data resolve small-scale exchange processes across the shelf-break front (the Antarctic Slope Front) and the front's biogeochemical signature. GENTOO demonstrated the capability of ocean gliders to play a key role in a future multi-disciplinary Southern Ocean observing system.

  12. Slope and curvature of microbreaking wind waves

    Science.gov (United States)

    Caulliez, G.

    2009-04-01

    Microscale breaking is commonly observed at sea for steep waves less than 30 cm in wavelength. This phenomenon generates high surface slope and curvature roughness at the water surface, which has numerous implications for air-sea exchange and remote-sensing studies. In particular, microbreaking affects momentum transfer from wind to waves, leads to formation of vortices in water, and plays a key role in scattering of electromagnetic and acoustic waves by the air-sea interface. The geometric properties of the parasitic capillaries generated upon steep steady gravity-capillary waves have been well studied over the last decades, both experimentally and numerically. However, owing to their variability, the basic features of naturally occurring wind wave breakers as observed at sea or even in laboratory are far from being identified up to now. To this end, an experimental investigation of microbreaking wind waves was made in a large wind wave tank which combined visualizations of wave breaker profiles with single-point wave elevation and slope measurements. We show that microscale breakers exhibit a characteristic signature in slope and curvature suggesting formation of a bulge on the forward face of the wave crest. Parasitic ripples however are not necessarily generated ahead the bulge. Such breakers are observed for a wide range of wave steepness and wave slope skewness, their structure being only weakly dependent on wavelength and wind forcing. The geometric properties of microbreakers are analysed statistically and compared with the results of the recent numerical simulations by Hung and Tsai (J. Phys. Oceanogr., 2009).

  13. Transhumanism, medical technology and slippery slopes

    OpenAIRE

    McNamee, M J; Edwards, S D

    2006-01-01

    In this article, transhumanism is considered to be a quasi‐medical ideology that seeks to promote a variety of therapeutic and human‐enhancing aims. Moderate conceptions are distinguished from strong conceptions of transhumanism and the strong conceptions were found to be more problematic than the moderate ones. A particular critique of Boström's defence of transhumanism is presented. Various forms of slippery slope arguments that may be used for and against transhumanism are discussed and on...

  14. Modelling Progressive Failure in Rock-slopes

    Science.gov (United States)

    Pons, M. Güell I.; Jaboyedoff, M.

    2009-04-01

    Rock failures are common in Alpine mountain chains and pose a threat to life and infrastructures. In general, rock slope stability is an interplay between existing discontinuities and development of new ones in intact material. In this work, we study progressive failure by means of numerical methods at multiple scales and using distinct element methods (DEM). Distinct element methods are of advantage because they account for discontinuities and are able to simulate the development of failure in time. The use of micro-parameters instead of constitutive laws allows studying the influence of heterogeneities present in the rock mass. In the first case, the code PFC-2D is used at the slope scale to test the influence of the slope geometry, the joint sets distribution and the joint set persistence in the case of toppling failures under various triggering mechanisms. Heterogeneity properties (cohesion and friction angle) are distributed randomly to simulate natural rock variability. In the second case, a cellular automata model, which is based on concepts of progressive failure in disordered systems, is used to explain the role of heterogeneities in the fracture process at a small scale. The results provide a link to time-to-failure predictions observed in some field cases. This study aims to be a base for the development of a model which permits to understand why some rock masses accelerate until global failure while other are capable to stabilize under the same conditions.

  15. Progress in Predicting Rock-Slope Failures

    Science.gov (United States)

    Korup, O.

    2015-12-01

    Recent research on predicting landslides has seen a massive increase in statistical and computational methods that are largely adapted from the fields of machine learning and data mining. Judging from a sample of some 150 recent scientific papers, the gross majority of the reported success rates of these statistical methods are overwhelmingly high and promising at between 71% and 98%. Perhaps surprisingly, though, the death toll and damage from landslides has remained elevated in the early 21st century, so that reliably predicting the occurrence of rock-slope failures without overfitting our models remains challenging. Here I review some of the recent advances in this field, and show how novel results from landslide seismology and landslide sedimentology have promoted our ability of detecting large rock-slope failures in mountainous terrain. Several new detailed investigations of the internal nature of large rockslide deposits, for example, help to reduce the confusion potential with macroscopically similar moraine debris, or microscopically similar fault breccia. I further outline some of the limitations of empirical models that use rainfall intensity-duration thresholds for landslide early warning, and of multivariate methods concerned with mapping landslide susceptibility at the regional scale. I conclude by discussing the occurrence of 'black swans' such as long-runout rock-ice avalanches in size distributions of rock-slope failures, and their implications for quantitative hazard appraisals.

  16. Statistics of the slope-method estimator.

    Science.gov (United States)

    Rocadenbosch, F; Comerón, A; Albiol, L

    2000-11-20

    The slope method has customarily been used and is still used for inversion of atmospheric optical parameters, extinction, and backscatter in homogeneous atmospheres from lidar returns. Our aim is to study the underlying statistics of the old slope method and ultimately to compare its inversion performance with that of the present-day nonlinear least-squares solution (the so-called exponential-curve fitting). The contents are twofold: First, an analytical study is conducted to characterize the bias and the mean-square-estimation error of the regression operator, which permits estimation of the optical parameters from the logarithm of the range-compensated lidar return. Second, universal plots for most short- and far-range tropospheric backscatter lidars are presented as a rule of thumb for obtaining the optimum regression interval length that yields unbiased estimates. As a result, the simple graphic basis of the slope method is still maintained, and its inversion performance improves up to that of the present-day computer-oriented exponential-curve fitting, which ends the controversy between these two algorithms.

  17. Reversible posterior leukoencephalopathy syndrome in a child treated with bevacizumab.

    Science.gov (United States)

    Levy, Carolyn Fein; Oo, Khine Zin; Fireman, Fernando; Pierre, Louisdon; Bania, Marita A; Sadanandan, Swayamprabha; Yamashiro, Darrell J; Glade Bender, Julia L

    2009-05-01

    Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF). Hypertension is a well-recognized, common side effect of VEGF blocking agents. The reversible posterior leukoencephalopathy syndrome (RPLS) has been described as a rare but serious consequence of bevacizumab administration. We present a case of a 6-year-old child with refractory hepatoblastoma who developed hypertensive crisis, seizures and MRI changes consistent with RPLS while receiving bevacizumab with gemcitabine and oxaliplatin. Findings completely resolved without neurologic sequelae with stringent blood-pressure control. Better understanding of risk for RPLS, prompt recognition and aggressive management will be required as bevacizumab gains wider use in pediatrics. (c) 2008 Wiley-Liss, Inc.

  18. The posterior triangle in radical neck surgery.

    Science.gov (United States)

    Skolnik, E M; Yee, K F; Friedman, M; Golden, T A

    1976-01-01

    We evaluate the importance of cancer spread to the lymphatic system in the posterior triangle. The posterior triangle tissues of 51 radical neck specimens were serially sectioned and studied for metastic involvement. The findings were correlated with the findings in the anterior triangle and the primary tumor. Of the 51 neck operations performed, 25 were elective and 26 were therapeutic for carcinoma of the larynx, pharynx, and oral cavity. Metastasis in the anterior triangles was detected in 88.4% of the therapeutic group and in 24.0% of the elective group. However, no metastasis in the posterior triangel was found in either group, regardless of the site of the tumor. We suggest that the posterior triangle can be totally preserved in radical neck surgery, which may make preservation of the spinal accessory nerve a more likely practice.

  19. Primary Burkitt lymphoma in the posterior mediastinum.

    Science.gov (United States)

    Chaari, Zied; Charfi, Slim; Hentati, Abdessalem; Ayadi, Ines; Abid, Hanene; Frikha, Imed

    2015-11-01

    A 13-year-old boy was admitted to our hospital with complaints of posterior chest pain and dyspnea. Computed tomography and magnetic resonance imaging of the chest revealed a mass in the posterior mediastinum, extending from T8 to T11 with intraspinal involvement. A percutaneous core needle biopsy confirmed the diagnosis of Burkitt lymphoma. He was treated according to the Lymphoma Malignancy B protocol 2001 arm C3, but he presented with liver and brain relapses and died 7.5 months after admission. Although lymphoma is rarely localized in the posterior mediastinum, it should be considered in the differential diagnosis of posterior mediastinal masses in children. © The Author(s) 2015.

  20. Posterior alien hand syndrome: case report

    International Nuclear Information System (INIS)

    Rohde, S.; Weidauer, S.; Lanfermann, H.; Zanella, F.

    2002-01-01

    The alien hand syndrome (AHS) is involuntary uncontrolled movement of an arm with a sense of estrangement from the limb itself. AHS was initially used to describe interhemispheric disconnection phenomena in patients with lesions in the anterior corpus callosum, but it has been found in patients with posterior cerebral lesions without involvement of the corpus callosum, for example parietal infarcts or corticobasal degeneration. The posterior alien hand syndrome is less frequent and presents with nonpurposive behaviour like lifting the arm or writhing fingers. We report an 80-year-old woman with a posterior AHS of the dominant right hand. MRI showed atrophy of the pre- and postcentral gyri without involvement of the corpus callosum. We discuss the aetiology of the posterior AHS and the differences from the anterior varieties. (orig.)

  1. Posterior reversible leukoencephalopathy syndrome after kratom ingestion.

    Science.gov (United States)

    Castillo, Austin; Payne, J Drew; Nugent, Kenneth

    2017-07-01

    Posterior reversible encephalopathy syndrome has been associated with hypertension, preeclampsia, cancer chemotherapy, and drugs of abuse, such as amphetamine and methamphetamine. We report a young man who suddenly developed severe headache, disorientation, and aphasia following ingestion of kratom and Adderall. Computed tomography and magnetic resonance imaging of his head revealed foci of vasogenic edema in the posterior occipital lobes, frontal lobes, and brainstem. In addition, he had a small area of hemorrhage in the left posterior occipital lobe. Lumbar puncture revealed an increased number of red blood cells but no other abnormalities. His initial blood pressure was elevated but returned to normal during hospitalization. This case suggests that kratom can cause posterior reversible encephalopathy syndrome and needs to be considered when patients present to emergency centers with headaches, confusion, and visual disturbances.

  2. Congenital abnormalities of the posterior fossa.

    Science.gov (United States)

    Bosemani, Thangamadhan; Orman, Gunes; Boltshauser, Eugen; Tekes, Aylin; Huisman, Thierry A G M; Poretti, Andrea

    2015-01-01

    The frequency and importance of the evaluation of the posterior fossa have increased significantly over the past 20 years owing to advances in neuroimaging. Nowadays, conventional and advanced neuroimaging techniques allow detailed evaluation of the complex anatomic structures within the posterior fossa. A wide spectrum of congenital abnormalities has been demonstrated, including malformations (anomalies due to an alteration of the primary developmental program caused by a genetic defect) and disruptions (anomalies due to the breakdown of a structure that had a normal developmental potential). Familiarity with the spectrum of congenital posterior fossa anomalies and their well-defined diagnostic criteria is crucial for optimal therapy, an accurate prognosis, and correct genetic counseling. The authors discuss the spectrum of posterior fossa malformations and disruptions, with emphasis on neuroimaging findings (including diagnostic criteria), neurologic presentation, systemic involvement, prognosis, and risk of recurrence. RSNA, 2015

  3. Weakly supervised object detection with posterior regularization

    OpenAIRE

    Bilen, Hakan; Pedersoli, Marco; Tuytelaars, Tinne

    2014-01-01

    Bilen H., Pedersoli M., Tuytelaars T., ''Weakly supervised object detection with posterior regularization'', 25th British machine vision conference - BMVC 2014, 12 pp., September 1-5, 2014, Nottingham, UK.

  4. Posterior Fossa Tumors and Intellectual Impairment

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-01-01

    Full Text Available The effect of cerebellar damage on intellectual function in 76 children treated surgically for malignant posterior fossa tumor was investigated at the Gustave Roussy Institute, Villejuif, and the Department of Pediatric Neurosurgery, Necker Hospital, Paris, France.

  5. Luxación posterior de hombro

    OpenAIRE

    Matson-Carballo Gustavo; Ramírez-Castro Jéssica Lorena

    2013-01-01

    Introduction: posterior shoulder dislocation is an infrequent pathology that is associated to electroshocks, convulsions and trauma in flexion and adduction of the superior extremities. Due to its clinical signs are slightly evident, it could be overlooked and become chronic. It might be accompanied of fractures of the proximal humerus. Clinical case: 39 years-of-age patient who consulted to the emergency service for presenting signs of posterior shoulder dislocation, without p...

  6. Longevity of posterior tooth dental restorations.

    Science.gov (United States)

    Christensen, Gordon J

    2005-02-01

    Several forms of restorative techniques are used for posterior teeth. They vary significantly in cost and longevity. The following restorative concepts are the most commonly used: amalgam, resin-based composite, PFM, cast gold alloy restorations and all-ceramic restorations. I suggest that patients be informed about the potential longevity of restorative treatment for posterior teeth as they make decisions about treatment for their oral restorative needs.

  7. Posterior atlantoaxial dislocation without odontoid fracture

    International Nuclear Information System (INIS)

    Chaudhary, Reema; Raut, Abhijit; Chaudhary, Kshitij; Metkar, Umesh; Rathod, Ashok; Sanghvi, Darshana

    2008-01-01

    We report a case of posterior atlantoaxial dislocation without a fracture of the odontoid in a 35-year-old woman. There have been nine reported cases of similar injury in the English literature. The integrity of the transverse ligament following posterior atlantoaxial dislocations has not been well documented in these reports. In the present case, MRI revealed an intact transverse ligament, which probably contributed to the stability of the C1-C2 complex following closed reduction. (orig.)

  8. Vermian agenesis without posterior fossa cyst

    International Nuclear Information System (INIS)

    Adamsbaum, C.; Moreau, V.; Bulteau, C.; Burstyn, J.; Lair Milan, F.; Kalifa, G.

    1994-01-01

    We report 11 cases of vermian partial agenesis without posterior fossa cyst or hemispheric abnormalities. Characteristic MR signs were: absence of the posterior lobe, hypoplasia of the anterior lobe, a narrow sagittal cleft separating the hemispheres (''buttocks sign'') and fourth ventricle deformity. The main clinical signs were complex oculomotor dysfunction and developmental delay. None of the patients had respiratory symptoms. Consideration is given to the relationship between Joubert syndrome and this entity as well as to embroyological data. (orig.)

  9. Delayed Single Stage Perineal Posterior Urethroplasty

    International Nuclear Information System (INIS)

    Ali, S.; Shahnawaz; Shahzad, I.; Baloch, M. U.

    2015-01-01

    Objective: To determine the delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture/distraction defect. Study Design: Descriptive case series. Place and Duration of Study: Department of Urology, Jinnah Postgraduate Medical Centre, Karachi, from January 2009 to December 2011. Methodology: Patients were selected for delayed single stage perineal posterior urethroplasty for treatment of posterior urethral stricture / distraction defect. All were initially suprapubically catheterized followed by definitive surgery after at least 3 months. Results: Thirty male patients were analyzed with a mean follow-up of 10 months, 2 patients were excluded as they developed failure in first 3 months postoperatively. Mean patients age was 26.25 ± 7.9 years. On follow-up, 7 patients (23.3 percentage) experienced recurrent stricture during first 10 months. Five (16.6 percentage) patients were treated successfully with single direct visual internal urethrotomy. Two patients (6.6 percentage) had more than one direct visual internal urethrotomy and considered failed. Re-do perineal urethroplasty was eventually performed. The overall success rate was 93.3 percentage with permissive criteria allowing single direct visual internal urethrotomy and 76.6% with strict criteria allowing no more procedures postoperatively. Conclusion: Posterior anastomotic urethroplasty offers excellent long-term results to patients with posterior urethral trauma and distraction defect even after multiple prior procedures. (author)

  10. Early endoscopic realignment in posterior urethral injuries.

    Science.gov (United States)

    Shrestha, B; Baidya, J L

    2013-01-01

    Posterior urethral injury requires meticulous tertiary care and optimum expertise to manage successfully. The aim of our study is to describe our experiences with pelvic injuries involving posterior urethra and their outcome after early endoscopic realignment. A prospective study was carried out in 20 patients with complete posterior urethral rupture, from November 2007 till October 2010. They presented with blunt traumatic pelvic fracture and underwent primary realignment of posterior urethra in our institute. The definitive diagnosis of urethral rupture was made after retrograde urethrography and antegrade urethrography where applicable. The initial management was suprapubic catheter insertion after primary trauma management in casualty. After a week of conservative management with intravenous antibiotics and pain management, patients were subjected to the endoscopic realignment. The follow up period was at least six months. The results were analyzed with SPSS software. After endoscopic realignment, all patients were advised CISC for the initial 3 months. All patients voided well after three months of CISC. However, 12 patients were lost to follow up by the end of 6 postoperative months. Out of eight remaining patients, two had features of restricture and were managed with DVU followed by CISC again. One patient with restricture had some degree of erectile dysfunction who improved significantly after phospodiesterase inhibitors. None of the patients had features of incontinence. Early endoscopic realignment of posterior urethra is a minimally invasive modality in the management of complete posterior urethral injury with low rates of incontinence and impotency.

  11. Traumatic lesions of the posterior urethra.

    Science.gov (United States)

    Velarde-Ramos, L; Gómez-Illanes, R; Campos-Juanatey, F; Portillo-Martín, J A

    2016-11-01

    The posterior urethral lesions are associated with pelvis fractures in 5-10% of cases. The posterior urethra is attached to the pelvis bone by puboprostatic ligaments and the perineal membrane, which explains why disruption of the pelvic ring can injure the urethra at this level. To identify suspected cases of posterior urethral trauma and to perform the diagnosis and its immediate or deferred management. Search in PubMed of articles related to traumatic posterior urethral lesions, written in English or Spanish. We reviewed the relevant publications including literature reviews and chapters from books related to the topic. With patients with pelvis fractures, we must always rule out posterior urethral lesions. The diagnostic examination of choice is retrograde urethrography, which, along with the severity of the condition, will determine the management in the acute phase and whether the treatment will be performed immediately or deferred. Early diagnosis and proper acute management decrease the associated complications, such as strictures, urinary incontinence and erectile dysfunction. Despite the classical association between posterior urethral lesions and pelvic fractures, the management of those lesions (whether immediate or deferred) remains controversial. Thanks to the growing interest in urethral disease, there are an increasing number of studies that help us achieve better management of these lesions. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Echocardiographic Wall Motion Abnormality in Posterior Myocardial Infarction: The Diagnostic Value of Posterior Leads

    Directory of Open Access Journals (Sweden)

    A Darehzereshki

    2008-06-01

    Full Text Available Background: For the purpose of ascertaining myocardial infarction (MI and ischemia, the sensitivity of the initial 12-lead ECG is inadequate. It is risky to diagnose posterior MI using only precordial reciprocal changes, since the other leads may be more optimally positioned for the identification of electrocardiographic changes. In this study, we evaluated the relationship between electrocardiography changes and wall motion abnormalities in patients with posterior MI for earlier and better diagnosis of posterior MI.Methods: In this prospective cross-sectional study, we enrolled patients with posterior MI who had come to the Emergency Department of Shariati Hospital with their first episode of chest pain. A 12-lead surface electrocardiogram using posterior leads (V7-V9 was performed for all participants. Patients with ST elevation >0.05 mV or pathologic Q wave in the posterior leads, as well as those with specific changes indicating posterior MI in V1-V2, were evaluated by echocardiography in terms of wall motion abnormalities. All data were analyzed using SPSS and p<0.05 were considered statistically significant.Results: Of a total 79 patients enrolled, 48 (60.8% were men, and the mean age was 57.35±8.22 years. Smoking (54.4% and diabetes (48% were the most prevalent risk factors. In the echocardiographic evaluation, all patients had wall motion abnormalities in the left ventricle and 19 patients (24.1% had wall motion abnormalities in the right ventricle. The most frequent segment with motion abnormality among the all patients was the mid-posterior. The posterior leads showed better positive predictive value than the anterior leads for posterior wall motion abnormality.Conclusion: Electrocardiography of the posterior leads in patients with acute chest pain can help in earlier diagnosis and in time treatment of posterior MI.

  13. Slope stabilization guide for Minnesota local government engineers.

    Science.gov (United States)

    2017-06-01

    This user guide provides simple, costeffective methods for stabilizing locally maintained slopes along roadways in Minnesota. Eight slope stabilization techniques are presented that local government engineers can undertake using locally available ...

  14. Stabilization of erodible slopes with geofibers and nontraditional liquid additives.

    Science.gov (United States)

    2013-05-01

    Instability of erodible slopes due to extreme climate events and of permafrost slopes due degradation and thawing is a significant : engineering problem for northern transportation infrastructure. Engineers continually look for mitigation alternative...

  15. Thermomechanical forcing of deep rock slope deformation: 1. Conceptual study of a simplified slope

    Science.gov (United States)

    Gischig, Valentin S.; Moore, Jeffrey R.; Evans, Keith F.; Amann, Florian; Loew, Simon

    2011-12-01

    Thermo-elastic rock slope deformation is often considered to be of relatively minor importance and limited to shallow depths subject to seasonal warming and cooling. In this study, we demonstrate how thermomechanical (TM) effects can drive rock slope deformation at greater depths below the annual thermal active layer. Here in Part 1 of two companion papers, we present 2D numerical models of a simplified slope subject to annual surface temperature cycles. The slope geometry and discontinuity sets are loosely based on the Randa instability considered in detail in Part 2. Results show that near-surface thermo-elastic stresses can propagate to depths of 100 m and more as a result of topography and elasticity of the rock mass. Shear dislocation along discontinuities can have both a reversible component controlled by discontinuity compliance and, provided that the stress state is sufficiently close to the strength limit, an irreversible component (i.e., slip). Induced slip increments are followed by stress redistribution resulting in the propagation of slip fronts. Thus, deformation and progressive rock slope failure can be driven solely by thermomechanical forcing. The influence of TM-induced stress changes becomes stronger for increasing numbers of critically stressed discontinuities and is enhanced if failure of discontinuities involves slip-weakening. The net TM effect acts as a meso-scale fatigue process, involving incremental discontinuity slip and hysteresis driven by periodic loading.

  16. The posterior condylar offset ratio and femoral anatomy in anterior versus posterior referencing total knee arthroplasty.

    Science.gov (United States)

    Almeida, P H; Vilaça, A

    2015-10-01

    The preservation of joint anatomy is one of the key issues in total knee arthroplasty. The effect of the prosthesis' referencing system, relative to femoral anatomy, remains unknown. It was sought to determine if femoral anatomy, following total knee arthroplasty is better maintained using either anterior referencing or posterior referencing prosthesis. The posterior condylar offset ratio (PCOR) was employed for preoperative and postoperative radiographic comparison of femoral condyles. It was hypothesized that posterior referencing prosthesis would better restore condylar morphology. Sixty-six patients undergoing a total knee arthroplasty with anterior referenced Zimmer(®) NexGen(®) LPS prosthesis and ninety-one with posterior referenced Tornier(®) HLS Noetos(®) were divided into two groups according to the prosthetic model used and retrospectively compared. PCOR was calculated as the quotient of the distance between the posterior condylar border and the tangent to the posterior cortex of the femoral diaphysis, and the distance between the posterior condylar border and the tangent to the anterior cortex of the femoral diaphysis. PCOR was determined preoperatively and postoperatively and compared within each group and between both groups. An increase in the PCOR (Panterior referencing and posterior referencing models. No difference was noted when the postoperative PCOR was compared between both groups (P=0.61). Both anterior and posterior referencing prosthesis lead to a similar increase of the PCOR following total knee arthroplasty. Level IV. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  17. Understanding slope behavior through microseismic monitoring

    Science.gov (United States)

    Arosio, Diego; Boccolari, Mauro; Longoni, Laura; Papini, Monica; Zanzi, Luigi

    2017-04-01

    It is well known that microseismic activity originates as an elastic stress wave at locations where the material is mechanically unstable. Monitoring techniques focusing on this phenomenon have been studied for over seventy years and are now employed in a wide range of applications. As far as the study of unstable slope is concerned, microseismic monitoring can provide real-time information about fracture formation, propagation and coalescence and may be an appropriate solution to reduce the risk for human settlements when structural mitigation interventions (e.g., rock fall nets and ditches) cannot cope with large rock volumes and high kinetic energies. In this work we present the datasets collected in a 4-year period with a microseismic monitoring network deployed on an unstable rock face in Northern Italy. We mainly focus on the classification and the interpretation of collected signals with the final aim of identifying microseismic events related to the kinematic and dynamic behavior of the slope. We have analyzed signal parameters both in time and frequency domains, spectrograms, polarization of 3-component recordings supported by principal component analysis. Clustering methodologies have been tested in order to develop an automatic classification routine capable to isolate a cluster with most of the events related to slope behavior and to discard all disturbances. The network features both geophones and meteorological sensors so that we could also explore the correlation between microseismic events and meteorological datasets, although no significant relationships emerged. On the contrary, it was found that the majority of the events collected by the network are short-time high-frequency signals generated by electromagnetic activity caused by near and far thunderstorms. Finally, we attempted a preliminary localization of the most promising events according to an oversimplified homogeneous velocity model to get a rough indication about the regions of the

  18. Western Ross Sea continental slope gravity currents

    Science.gov (United States)

    Gordon, Arnold L.; Orsi, Alejandro H.; Muench, Robin; Huber, Bruce A.; Zambianchi, Enrico; Visbeck, Martin

    2009-06-01

    Antarctic Bottom Water of the world ocean is derived from dense Shelf Water that is carried downslope by gravity currents at specific sites along the Antarctic margins. Data gathered by the AnSlope and CLIMA programs reveal the presence of energetic gravity currents that are formed over the western continental slope of the Ross Sea when High Salinity Shelf Water exits the shelf through Drygalski Trough. Joides Trough, immediately to the east, offers an additional escape route for less saline Shelf Water, while the Glomar Challenger Trough still farther east is a major pathway for export of the once supercooled low-salinity Ice Shelf Water that forms under the Ross Ice Shelf. The Drygalski Trough gravity currents increase in thickness from ˜100 to ˜400 m on proceeding downslope from ˜600 m (the shelf break) to 1200 m (upper slope) sea floor depth, while turning sharply to the west in response to the Coriolis force during their descent. The mean current pathway trends ˜35° downslope from isobaths. Benthic-layer current and thickness are correlated with the bottom water salinity, which exerts the primary control over the benthic-layer density. A 1-year time series of bottom-water current and hydrographic properties obtained on the slope near the 1000 m isobath indicates episodic pulses of Shelf Water export through Drygalski Trough. These cold (34.75) pulses correlate with strong downslope bottom flow. Extreme examples occurred during austral summer/fall 2003, comprising concentrated High Salinity Shelf Water (-1.9 °C; 34.79) and approaching 1.5 m s -1 at descent angles as large as ˜60° relative to the isobaths. Such events were most common during November-May, consistent with a northward shift in position of the dense Shelf Water during austral summer. The coldest, saltiest bottom water was measured from mid-April to mid-May 2003. The summer/fall export of High Salinity Shelf Water observed in 2004 was less than that seen in 2003. This difference, if real

  19. Transhumanism, medical technology and slippery slopes.

    Science.gov (United States)

    McNamee, M J; Edwards, S D

    2006-09-01

    In this article, transhumanism is considered to be a quasi-medical ideology that seeks to promote a variety of therapeutic and human-enhancing aims. Moderate conceptions are distinguished from strong conceptions of transhumanism and the strong conceptions were found to be more problematic than the moderate ones. A particular critique of Boström's defence of transhumanism is presented. Various forms of slippery slope arguments that may be used for and against transhumanism are discussed and one particular criticism, moral arbitrariness, that undermines both weak and strong transhumanism is highlighted.

  20. Clustering Moving Objects Using Segments Slopes

    OpenAIRE

    Mohamed E. El-Sharkawi; Hoda M. O. Mokhtar; Omnia Ossama

    2011-01-01

    Given a set of moving object trajectories, we show how to cluster them using k-meansclustering approach. Our proposed clustering algorithm is competitive with the k-means clusteringbecause it specifies the value of “k” based on the segment’s slope of the moving object trajectories. Theadvantage of this approach is that it overcomes the known drawbacks of the k-means algorithm, namely,the dependence on the number of clusters (k), and the dependence on the initial choice of the clusters’centroi...

  1. Intertidal beach slope predictions compared to field data

    NARCIS (Netherlands)

    Madsen, A.J.; Plant, N.G.

    2001-01-01

    This paper presents a test of a very simple model for predicting beach slope changes. The model assumes that these changes are a function of both the incident wave conditions and the beach slope itself. Following other studies, we hypothesized that the beach slope evolves towards an equilibrium

  2. [BIOMECHANICS STUDY ON ACETABULAR POSTERIOR WALL FRACTURE].

    Science.gov (United States)

    Tang, Yang; Hu Xiaopeng; Lu, Xiongwei; Zhang, Yuntong; Zhang, Chuncai; Wang, Panfeng; Zhao, Xue

    2015-08-01

    To study the experimental biomechanics of acetabular posterior wall fractures so as to provide theoretical basis for its clinical treatment. Six formalin-preserved cadaveric pelvises were divided into groups A and B (n=3). The fracture models of superior-posterior wall and inferior-posterior wall of the acetabulum were created on both hips in group A; fractures were fixed with two interfragmentary screws and a locking reconstruction plate. The fracture models of superior-posterior wall of acetabulum were created on both hips in group B; fractures were fixed with two interfragmentary screws and a locking reconstruction plate at one side, and with acetabular tridimensional memory fixation system (ATMFS) at the other side. The biomechanical testing machine was used to load to 1 500 N at 10 mm/min speed for 30 seconds. The displacement of superior and inferior fracture sites was analyzed with the digital image correlation technology. No fracture or internal fixation breakage occurred during loading and measuring; the displacement valuess of the upper and lower fracture lines were below 2 mm (the clinically tolerable maximum value) in 2 groups. In group A, the displacement values of the upper and lower fracture lines at superior-posterior wall fracture site were significantly higher than those at inferior-posterior wall fracture site (P fracture line were significantly higher than those of lower fracture line (P fracture types. In group B, the displacement values of the upper and lower fracture lines at the side fixed with screws and a locking reconstruction plate were similar to the values at the side fixed with ATMFS, all being close to 2 mm; the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P acetabulum is much greater than that of the inferior-posterior wall of acetabulum and they should be discriminated, which might be the reasons of reduction loss, femoral head subluxation, and traumatic arthritis

  3. Management of posterior urethral disruption injuries.

    Science.gov (United States)

    Myers, Jeremy B; McAninch, Jack W

    2009-03-01

    Posterior urethral disruption is a traumatic injury to the male urethra, which most often results from pelvic fracture. After trauma, the distraction defect between the two ends of the urethra often scars and becomes fibrotic, blocking the urethra and bladder emptying. Increasing evidence suggests that many posterior urethral disruptions occur at the junction between the membranous urethra and the bulbar urethra, which is distal to the rhabdosphincter. In the acute setting, when a posterior urethral disruption is suspected, retrograde urethrography should be performed. Posterior urethral disruptions can be managed acutely by realignment of the urethra over a urethral catheter or by placement of a suprapubic catheter for bladder drainage only. Once fibrosis has stabilized, the patient can undergo posterior urethroplasty. In most cases, this procedure can be performed via a perineal approach in a single-stage surgery. The results of this single-stage perineal urethroplasty are excellent, and a patent urethra can be re-established in the majority of men who undergo surgery.

  4. Pars plana vitrectomy with posterior iris claw implantation for posteriorly dislocated nucleus and intraocular lens

    Directory of Open Access Journals (Sweden)

    Kishor B Patil

    2011-01-01

    Full Text Available We evaluated the safety and efficacy of pars plana vitrectomy (PPV with primary posterior iris claw intraocular lens (IOL implantation in cases of posterior dislocation of nucleus and IOL without capsular support. This was a retrospective interventional case series. Fifteen eyes underwent PPV with primary posterior iris claw IOL implantation performed by a single vitreoretinal surgeon. The main outcome measures were changes in best corrected visual acuity and anterior and posterior segment complications. A total of 15 eyes were included in this study. Eight had nucleus drop, three had IOL drop during cataract surgery and four had traumatic posterior dislocation of lens. The final postoperative best corrected visual acuity was 20/60 or better in 11 patients. This procedure is a viable option in achieving good functional visual acuity in eyes without capsular support.

  5. Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.

    Science.gov (United States)

    Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

    2014-05-01

    One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment.

  6. Assessment and mapping of slope stability based on slope units: A ...

    Indian Academy of Sciences (India)

    4) 1153–1171. Muntohar A S and Liao H J 2010 Rainfall infiltration: Infi- nite slope model for landslides triggering by rainstorm;. Nat. Hazards 54(3) 967–984. Muthu K, Petrou M, Tarantino C and Blonda P 2008 Land- slide possibility mapping ...

  7. Late presentation of posterior urethral valves.

    Science.gov (United States)

    Jalbani, Imran Khan; Biyabani, Syed Raziuddin

    2014-05-01

    Presence of posterior urethral valves (PUV) is the most common cause of urinary tract obstruction in the male neonate. Late presentation occurs in 10% of cases. We present a case of PUVs in an adult male who presented with history of obstructive lower urinary tract symptoms and hematuria. On evaluation, he was found to have raised serum creatinine level. A voiding cystourethrogram (VCUG) could not be completely performed because of narrowing in the posterior urethra. A rigid urethrocystoscopy was performed at which he was found to have type-I posterior urethral valve which were fulgurated. A repeat uroflowmetry revealed maximum flow rate of 12 ml/second. This case highlights that PUVs is not solely a disease of infancy but may also present late. VCUG is the radiological investigation of choice but the diagnosis may be missed. A urethrocystoscopy is advised if there is a high index of suspicion.

  8. Posterior predictive checking of multiple imputation models.

    Science.gov (United States)

    Nguyen, Cattram D; Lee, Katherine J; Carlin, John B

    2015-07-01

    Multiple imputation is gaining popularity as a strategy for handling missing data, but there is a scarcity of tools for checking imputation models, a critical step in model fitting. Posterior predictive checking (PPC) has been recommended as an imputation diagnostic. PPC involves simulating "replicated" data from the posterior predictive distribution of the model under scrutiny. Model fit is assessed by examining whether the analysis from the observed data appears typical of results obtained from the replicates produced by the model. A proposed diagnostic measure is the posterior predictive "p-value", an extreme value of which (i.e., a value close to 0 or 1) suggests a misfit between the model and the data. The aim of this study was to evaluate the performance of the posterior predictive p-value as an imputation diagnostic. Using simulation methods, we deliberately misspecified imputation models to determine whether posterior predictive p-values were effective in identifying these problems. When estimating the regression parameter of interest, we found that more extreme p-values were associated with poorer imputation model performance, although the results highlighted that traditional thresholds for classical p-values do not apply in this context. A shortcoming of the PPC method was its reduced ability to detect misspecified models with increasing amounts of missing data. Despite the limitations of posterior predictive p-values, they appear to have a valuable place in the imputer's toolkit. In addition to automated checking using p-values, we recommend imputers perform graphical checks and examine other summaries of the test quantity distribution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Left posterior BA37 is involved in object recognition: a TMS study

    DEFF Research Database (Denmark)

    Stewart, Lauren; Meyer, Bernd-Ulrich; Frith, Uta

    2001-01-01

    Functional imaging studies have proposed a role for left BA37 in phonological retrieval, semantic processing, face processing and object recognition. The present study targeted the posterior aspect of BA37 to see whether a deficit, specific to one of the above types of processing could be induced...

  10. Effects of slope gradient on hydro-erosional processes on an aeolian sand-covered loess slope under simulated rainfall

    Science.gov (United States)

    Zhang, F. B.; Yang, M. Y.; Li, B. B.; Li, Z. B.; Shi, W. Y.

    2017-10-01

    The aeolian sand-covered loess slope of the Wind-Water Erosion Crisscross Region of the Loess Plateau in China may play a key role in contributing excessive sediment to the Yellow River. Understanding its hydro-erosional processes is crucial to assessing, controlling and predicting soil and water losses in this region and maintaining the ecological sustainability of the Yellow River. Simulated rainfall (intensity 90 mm h-1) was used to investigate the runoff and soil loss from loess slopes with different slope gradients (18%, 27%, 36%, 47%, and 58%) and overlying sand layer thicknesses (0, 5 and 10 cm). As compared with uncovered loess slopes, an overlying sand layer delayed runoff production, reduced cumulative runoff and increased cumulative soil loss, as well as enhancing variations among slope gradients. Cumulative runoff and soil loss from the sand-covered loess slopes increased with increasing slope gradients and then slightly decreased, with a peak at about 47% gradient; they both were greater from the 10-cm sand-covered loess slope than from the 5-cm except for with 18% slope gradient. In general, differences in cumulative runoff between sand layer thicknesses became smaller, while those in cumulative soil loss became larger, with increasing slope gradient. Runoff and soil loss rates on the sand-covered loess slopes exhibited unimodal distributions during the rainstorms. Maximum values tended to occur at the same rain duration, and increased considerably with increasing slope gradient and sand layer thickness on slopes that were less than 47%. Liquefaction process might occur on the lower loess slopes covered with thinner sand layers but failures similar to shallow landslides might occur when the sand layer was thicker on steeper slopes. The presence of an overlying sand layer changed the relationship between runoff and soil loss rates during intense rainstorms and this change varied with different slope gradients. Our results demonstrated that the effects

  11. Transverse posterior element fractures associated with torsion

    International Nuclear Information System (INIS)

    Abel, M.S.

    1989-01-01

    Six examples of a previously undescribed class of transverse vertebral element fractures are presented. These fractures differ from Chance and Smith fractures and their variants in the following respects: (1) the etiology is torsion and not flexion; (2) there is neither distraction of posterior ring fragments nor posterior ligament tears; (3) in contrast to Chance and Smith fractures, extension of the fracture into the vertebral body is absent or minimal; (4) the transverse process of the lumbar vertebra is avulsed at its base with a vertical fracture, not split horizontally. These fractures occur in cervical, lumbar, and sacral vertebrae in normal or compromised areas of the spine. (orig.)

  12. Posterior sternoclavicular dislocation: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, So Hwa; Kim, Ki Sun; Kim, Ki Jun [Dept. of Radiology, Incheon St. Mary' s Hospital, The Catholic University of Korea College of Medicine, Incheon (Korea, Republic of)

    2015-02-15

    Traumatic sternoclavicular joint dislocation is an uncommon injury, and posterior sternoclavicular dislocation occurs less frequently compared to anterior sternoclavicular dislocation. However, this type of dislocation has the potential for serious complications due to compression or laceration of the mediastinal structures. The diagnosis can be difficult using plain radiographs alone due to radiographic-anatomic superimposition. Therefore, posterior sternoclavicular dislocation is easily missed at the initial clinical evaluation. Contrast-enhanced computed tomography is required for a definite diagnosis and to assess associated mediastinal injuries.

  13. Posterior leukoencephalopathy syndrome in poststretococcal acute glomerulonephritis

    International Nuclear Information System (INIS)

    Bazzino Borzone, F.; Pandolfo Arias, M.; Protasio Palomino, L.; Pujadas Ferrer, M.; Cerisola Cardozo, A.; Gonzalez, G.; Caggiani Malzone, M.; Rubio Santoro, I.

    2005-01-01

    Reversible posterior leukoencephalopathy (LEPR) is a clinical entity that affects radiation usually the white matter of the cerebral hemispheres. It is frequently associated with acute arterial hypertension and immunosuppressive therapy, among other causes. The clinical presentation is varied, with headache, nausea, vomiting, impaired consciousness and abnormal behavior, seizures and visual disturbances, symptoms that often regress. Computed tomography (CT) and magnetic resonance imaging (MRI) images show white matter edema predominantly in posterior regions of the brain. We present a 10 year old boy with leprosy in the course of a nephrotic syndrome secondary to acute diffuse glomerunefritis (GNDA) poststreptococcal. (author) [es

  14. Malignant ectomesenchymoma of the posterior mediastinum

    International Nuclear Information System (INIS)

    Khan, M. H.; Iqbal, R.; Hafeez-UR-Rehman; Yaqub, N.; Anwar-ul-Haq

    2001-01-01

    The surgical management of a four years old female child, presented at the Islamic International Medical Complex (IIMC), Islamabad, with three months history of recurrent chest infections and failure to thrive, is discussed. Posterior mediastinal tumor was diagnosed radiologically. Tumor had flimsy attachments with pericardium and thoracic aorta but was densely adherent with lower lobe of left lung. The tumor was completely removed along with a segment of lung. The postoperative recovery was uneventful. The diagnosis of malignant ectomesenchymoma was made on histopathology. The patients is well in follow-up. This is the first reported case of malignant ectomesenchymoma arising within posterior mediastinum. (author)

  15. Methodologies for risk analysis in slope instability

    International Nuclear Information System (INIS)

    Bernabeu Garcia, M.; Diaz Torres, J. A.

    2014-01-01

    This paper is an approach to the different methodologies used in conducting landslide risk maps so that the reader can get a basic knowledge about how to proceed in its development. The landslide hazard maps are increasingly demanded by governments. This is because due to climate change, deforestation and the pressure exerted by the growth of urban centers, damage caused by natural phenomena is increasing each year, making this area of work a field of study with increasing importance. To explain the process of mapping a journey through each of the phases of which it is composed is made: from the study of the types of slope movements and the necessary management of geographic information systems (GIS) inventories and landslide susceptibility analysis, threat, vulnerability and risk. (Author)

  16. Positive Surge Propagation in Sloping Channels

    Directory of Open Access Journals (Sweden)

    Daniele Pietro Viero

    2017-07-01

    Full Text Available A simplified model for the upstream propagation of a positive surge in a sloping, rectangular channel is presented. The model is based on the assumptions of a flat water surface and negligible energy dissipation downstream of the surge, which is generated by the instantaneous closure of a downstream gate. Under these hypotheses, a set of equations that depends only on time accurately describes the surge wave propagation. When the Froude number of the incoming flow is relatively small, an approximate analytical solution is also proposed. The predictive ability of the model is validated by comparing the model results with the results of an experimental investigation and with the results of a numerical model that solves the full shallow water equations.

  17. Development of kenaf mat for slope stabilization

    Science.gov (United States)

    Ahmad, M. M.; Manaf, M. B. H. Ab; Zainol, N. Z.

    2017-09-01

    This study focusing on the ability of kenaf mat to act as reinforcement to laterite compared to the conventional geosynthetic in term of stabilizing the slope. Kenaf mat specimens studied in this paper are made up from natural kenaf fiber with 3mm thickness, 150mm length and 20mm width. With the same size of specimens, geosynthetic that obtain from the industry are being tested for both direct shear and tensile tests. Plasticity index of the soil sample used is equal to 13 which indicate that the soil is slightly plastic. Result shows that the friction angle of kenaf mat is higher compared to friction between soil particles itself. In term of resistance to tensile load, the tensile strength of kenaf mat is 0.033N/mm2 which is lower than the tensile strength of geosynthetic.

  18. Alaskan North Slope Oil & Gas Transportation Support

    Energy Technology Data Exchange (ETDEWEB)

    Lilly, Michael Russell [Geo-Watersheds Scientific LLC, Fairbanks, AK (United States)

    2017-03-31

    North Slope oil and gas resources are a critical part of US energy supplies and their development is facing a period of new growth to meet increasing national energy needs. While this growth is taking place in areas active in development for more than 20 years, there are many increasing environmental challenges facing industry and management agencies. A majority of all exploration and development activities, pipeline maintenance and other field support activities take place in the middle of winter, when the fragile tundra surface is more stable. The window for the critical oil and gas winter operational season has been steadily decreasing over the last 25 years. The number of companies working on the North Slope is increasing. Many of these companies are smaller and working with fewer resources than the current major companies. The winter operations season starts with the tundra-travel opening, which requires 15 cm of snow on the land surface in the coastal management areas and 23 cm in the foothills management areas. All state managed areas require -5°C soil temperatures at a soil depth of 30 cm. Currently there are no methods to forecast this opening date, so field mobilization efforts are dependent on agency personnel visiting field sites to measure snow and soil temperature conditions. Weeks can be easily lost in the winter operating season due to delays in field verification of tundra conditions and the resulting mobilization. After the season is open, a significant percentage of exploration, construction, and maintenance do not proceed until ice roads and pads can be built. This effort is dependent on access to lake ice and under-ice water. Ice chipping is a common ice-road construction technique used to build faster and stronger ice roads. Seasonal variability in water availability and permitting approaches are a constant constraint to industry. At the end of the winter season, projects reliant on ice-road networks are often faced with ending operations

  19. ASPECTS OF DRIP IRRIGATION ON SLOPES

    Directory of Open Access Journals (Sweden)

    Oprea Radu

    2010-01-01

    Full Text Available Nowadays, water and its supply raise problems of strategic importance, of great complexity, being considered one of the keys to sustainable human development. Drip irrigation consists in the slow and controlled administration of water in the area of the root system of the plants for the purposes of fulfilling their physiological needs and is considered to be one of the variants of localized irrigation. Water is distributed in a uniform and slow manner, drop by drop, in a quantity and with a frequency that depend on the needs of the plant, thanks to the exact regulation of the water flow rate and pressure, as well as to the activation of the irrigation based on the information recorded by the tensiometer with regard to soil humidity. This method enables the exact dosage of the water quantity necessary in the various evolution stages of the plant, thus eliminating losses. By applying the irrigation with 5 liters of water per linear meter, at a 7 days interval, in the month of august, for a vine cultivated on a slope, in layers covered with black film and irrigated via dropping, soil humidity immediately after irrigation reaches its highest level, but within the limits of active humidity, on the line of the irrigation band. Three days later, the water content of the soil in the layer is relatively uniform, and, after this interval, it is higher in the points situated at the basis of the film. This technology of cultivation on slopes favors the accumulation, in the soil, of the water resulted from heavy rains and reduces soil losses as a result of erosion.

  20. An alternative soil nailing system for slope stabilization: Akarpiles

    Science.gov (United States)

    Lim, Chun-Lan; Chan, Chee-Ming

    2017-11-01

    This research proposes an innovative solution for slope stabilization with less environmental footprint: AKARPILES. In Malaysia, landslide has become common civil and environmental problems that cause impacts to the economy, safety and environment. Therefore, effective slope stabilization method helps to improve the safety of public and protect the environment. This study focused on stabilizing surfacial slope failure. The idea of AKARPILES was generated from the tree roots system in slope stabilization. After the piles are installed in the slope and intercepting the slip plane, grout was pumped in and discharged through holes on the piles. The grout then filled the pores in the soil with random flow within the slip zone. SKW mixture was used to simulate the soil slope. There were two designs being proposed in this study and the prototypes were produced by a 3D printer. Trial mix of the grout was carried out to obtain the optimum mixing ratio of bentonite: cement: water. A series of tests were conducted on the single-pile-reinforced slope under vertical slope crest loading condition considering different slope gradients and nail designs. Parameters such as ultimate load, failure time and failure strain were recorded and compared. As comparison with the unreinforced slope, both designs of AKARPILES showed better but different performances in the model tests.

  1. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Aklik, P.

    2012-01-01

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author) [de

  2. A posterior tibial tendon skipping rope

    NARCIS (Netherlands)

    van Sterkenburg, M. N.; Haverkamp, D.; van Dijk, C. N.; Kerkhoffs, G. M. M. J.

    2010-01-01

    This report presents an athletic patient with swelling and progressive pain on the posteromedial side of his right ankle on weight bearing. MRI demonstrated tenosynovitis and suspicion of a length rupture. On posterior tibial tendoscopy, there was no rupture, but medial from the tendon a tissue cord

  3. Posterior Predictive Model Checking in Bayesian Networks

    Science.gov (United States)

    Crawford, Aaron

    2014-01-01

    This simulation study compared the utility of various discrepancy measures within a posterior predictive model checking (PPMC) framework for detecting different types of data-model misfit in multidimensional Bayesian network (BN) models. The investigated conditions were motivated by an applied research program utilizing an operational complex…

  4. Selective posterior lumbosacral rhizotomy for the management ...

    African Journals Online (AJOL)

    One hundred and sixty-eight patients had selective lumbosacral posterior rhizotomies for the treatment of cerebral palsy spasticity at Red Cross War Memorial Children's Hospital and Groote Schuur Hospital during the 10-year period 1981 - 1991. There was no mortality and insignificant early postoperative morbidity.

  5. Posterior skulderluksation--en diagnostisk udfordring

    DEFF Research Database (Denmark)

    Trollegaard, Anton Mitchell

    2009-01-01

    A case of posterior shoulder dislocation is described. The dislocation was misinterpreted twice clinically and radiographically in two different casualty departments before it was diagnosed and treated with closed reposition in a third facility. Treatment was conservative and the arm was placed...... in an abduction sling for four weeks with subsequent active physiotherapy. Udgivelsesdato: 2009-Aug...

  6. stabilisation of posterior sternoclavicular joint dislocation using

    African Journals Online (AJOL)

    A case is reported where palmaris longus tendon was used to stabilise the joint following open reduction. INTRODUCTION. Posterior Sternoclavicular joint dislocation is a relatively rare injury and is reported to have been first documented by Sir Astley Cooper in 1824 (1, 2). It is a potentially life threatening injury due to the ...

  7. Hindfoot endoscopy for posterior ankle pain

    NARCIS (Netherlands)

    van Dijk, C. Niek

    2006-01-01

    Hindfoot pain can be caused by a variety of pathologies, most of which can be diagnosed and treated with endoscopy. The main indications are posterior tibial tenosynovectomy, diagnosis of a longitudinal peroneus brevis rupture, peroneal tendon adhesiolysis, flexor hallucis longus release, os

  8. Posterior reversible encephalopathy syndrome: Some novel ...

    African Journals Online (AJOL)

    Two cases occurred following cerebral anoxia due to accidental strangulation and near-drowning, respectively. The third patient, a child known to have E-β thalassaemia, presented with transient encephalopathy following blood transfusion but involving the anterior brain rather than the posterior part classically described in ...

  9. Frozen shoulder or missed posterior dislocation?

    African Journals Online (AJOL)

    capsule and the posterior band of the inferior GH ligament. Dynamic structures are the shoulder girdle muscles and the rotator cuff. Traumatic PSD occurs when ... and subscapularis contractures, an insertion of the prosthesis is made in relatively anteverted orientation, or normal prosthetic retroversion with anterior capsular ...

  10. Extensive Supratentorial Hemorrhages Following Posterior Fossa ...

    African Journals Online (AJOL)

    Remote supratentorial hematoma soon after posterior fossa surgery for the removal of a space-occupying lesion is a rare but dramatic and dreaded complication, carrying significant morbidity and mortality. A 47-year-old woman presented with headache of 1-year duration that worsened over last 2 months, progressive ...

  11. POSTERIOR APPROACH FOR HIP ARTHROPLASTY: A SINGLE ...

    African Journals Online (AJOL)

    The most common indication was osteoarthritis. Two complications were encountered; surgical site infection and post-operative cerebrovascular accident. There were no dislocations. Conclusions: The posterior approach is a viable approach for hip arthroplasty for use in Kenya with low complication rates. INTRODUCTION.

  12. Posterior arch defects of the cervical spine

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, A.M.; Wechsler, R.J.; Landy, M.D.; Wetzner, S.M.; Goldstein, S.A.

    1982-05-01

    Spondylolysis and absence of the pedicle are congenital anomalies of the posterior cervical spine. Their roentgenographic changes may be confused with other more serious entities which may necessitate either emergent therapy or require extensive diagnostic testing and treatment. Four cases are present and the literature is reviewed. A hypothesis for the embryologic etiology of these entities is proposed.

  13. Posterior arch defects of the cervical spine

    International Nuclear Information System (INIS)

    Schwartz, A.M.; Wechsler, R.J.; Landy, M.D.; Wetzner, S.M.; Goldstein, S.A.

    1982-01-01

    Spondylolysis and absence of the pedicle are congenital anomalies of the posterior cervical spine. Their roentgenographic changes may be confused with other more serious entities which may necessitate either emergent therapy or require extensive diagnostic testing and treatment. Four cases are present and the literature is reviewed. A hypothesis for the embryologic etiology of these entities is proposed. (orig.)

  14. Restoration of the endodontically treated posterior tooth

    Directory of Open Access Journals (Sweden)

    Andrea Polesel

    2014-06-01

    Results and conclusions: Direct adhesive restorations, indirect bonded restorations and traditional full crown are three therapeutic options for the single posterior endodontically treated teeth. The amount of remaining sound tooth structure is the most significant factor influencing the therapeutic approach. The clinician's operative skill is a determining aspect for long-term success of adhesive inlays.

  15. From incipient slope instability through slope deformation to catastrophic failure - Different stages of failure development on the Ivasnasen and Vollan rock slopes (western Norway)

    Science.gov (United States)

    Oppikofer, T.; Saintot, A.; Hermanns, R. L.; Böhme, M.; Scheiber, T.; Gosse, J.; Dreiås, G. M.

    2017-07-01

    The long-term evolution of rock slope failures involves different stages, from incipience of slope instability to catastrophic failure, through a more or less long-lasting slope deformation phase that also involves creeping or sliding. Topography, lithology, and structural inheritance are the main intrinsic factors that influence this evolution. Here, we investigate the role of these intrinsic factors on the rock slope failure development of the Ivasnasen and Vollan rock slopes (Sunndal Valley, western Norway) using a multitechnique approach that includes geomorphologic and structural field mapping, kinematic analysis, terrestrial cosmogenic nuclide exposure dating, topographic reconstruction, and deformation quantification. Ivasnasen is a rock slope failure complex with several past rock slope failures and a present unstable rock slope, located on a cataclinal NW-facing slope and developed in augen gneiss. Vollan on the opposite valley side is a deep-seated gravitational slope deformation (DSGSD) affecting the whole mountainside, developed in quartzite in the upper part and micaschist in the lower part. These different lithologies belong to different nappe complexes that were emplaced and folded into a series of syn- and anticlines during the Caledonian orogeny. These folds lead to different lithologies being exposed in different structural orientations on the opposite valley flanks, which in turn leads to different types and evolution of rock slope failures. At Ivasnasen the 45°-55° NW-dipping ductile foliation allowed for a fairly simple planar sliding mechanism for the 1.2 million m3 post-glacial rock slope failure. Failure occurred ca. 3.3 ka ago after a short period of prefailure deformation. For the present 2.2 million m3 unstable rock slope at Ivasnasen, a steepening of the foliation at the toe impedes such a mechanism and up to 10 m of displacement has not lead to a catastrophic failure yet. The Vollan DSGSD is characterized by a steep major back scarp

  16. Simulating the seismic behaviour of soil slopes and embankments

    DEFF Research Database (Denmark)

    Zania, Varvara; Tsompanakis, Yiannis; Psarropoulos, Prodromos

    2010-01-01

    In the current study the clarification of the main assumptions, related to the two most commonly used methods of seismic slope stability analysis (pseudostatic and permanent deformation) is attempted. The seismic permanent displacements and the corresponding seismic coefficients were determined via...... parametric dynamic numerical analyses taking into account not only the main parameters dominating the seismic slope stability, but also the inherent assumptions of the applied approaches that affect the obtained results. The investigation conclude to a realistic procedure for seismic slope stability...

  17. Overpressure, Flow Focusing, Compaction and Slope Stability on the continental slope: Insights from IODP Expedition 308

    Science.gov (United States)

    Flemings, P. B.

    2010-12-01

    Integrated Ocean Drilling Program Expepedition 308 used direct measurements of pore pressure, analysis of hydromechanical properties, and geological analysis to illuminate how sedimentation, flow focusing, overpressure, and slope stability couple beneath the seafloor on the deepwater continental slope in the Gulf of Mexico. We used pore pressure penetrometers to measure severe overpressures (60% of the difference between lithostatic stress and hydrostatic pressure) that extend from the seafloor for 100’s of meters. We ran uniaxial consolidation experiments on whole core and found that although permeability is relatively high near the seafloor, the sediments are highly compressible. As a result, the coefficient of consolidation (the hydraulic diffusivity) is remarkably constant over a large range of effective stresses. This behavior accounts for the high overpressure that begins near the seafloor and extends to depth. Forward modeling suggests that flow is driven laterally along a permeable unit called the Blue Unit. Calculations suggest that soon after deposition, lateral flow lowered the effective stress and triggered the submarine landslides that we observe. Later in the evolution of this system, overpressure may have pre-conditioned the slope to failure by earthquakes. Results from IODP Expedition 308 illustrate how pore pressure and sedimentation control the large-scale form of continental margins, how submarine landslides form, and provide strategies for designing stable drilling programs.

  18. Posterior Cortical Atrophy: Visuomotor Deficits in Reaching and Grasping

    Directory of Open Access Journals (Sweden)

    Benjamin P Meek

    2013-06-01

    Full Text Available Posterior Cortical Atrophy (PCA is a rare clinical syndrome characterised by the predominance of higher-order visual disturbances such as optic ataxia, a characteristic of Balint’s syndrome. Deficits result from progressive neurodegeneration of occipito-temporal and occipito-parietal cortices. The current study sought to explore the visuomotor functioning of four individuals with PCA by testing their ability to reach out and grasp real objects under various viewing conditions. Experiment 1 had participants reach out and grasp simple, rectangular blocks under visually- and memory-guided conditions. Experiment 2 explored participants’ abilities to accurately reach for objects located in their visual periphery. This investigation revealed that PCA patients demonstrate many of the same deficits that have been previously reported in other individuals with optic ataxia, such as ‘magnetic misreaching’ – a pathological reaching bias towards the point of visual fixation when grasping peripheral targets. Unlike many other individuals with optic ataxia, however, the patients in the current study also show symptoms indicative of damage to the more perceptual stream of visual processing, including abolished grip scaling during memory-guided grasping and deficits in face and object identification. These investigations are the first to perform a quantitative analysis of the visuomotor deficits exhibited by patients with Posterior Cortical Atrophy. Critically, this study helps characterize common symptoms of PCA, a vital first step for generating effective diagnostic criteria and therapeutic strategies for this understudied neurodegenerative disorder.

  19. A Hybrid FEM-ANN Approach for Slope Instability Prediction

    Science.gov (United States)

    Verma, A. K.; Singh, T. N.; Chauhan, Nikhil Kumar; Sarkar, K.

    2016-09-01

    Assessment of slope stability is one of the most critical aspects for the life of a slope. In any slope vulnerability appraisal, Factor Of Safety (FOS) is the widely accepted index to understand, how close or far a slope from the failure. In this work, an attempt has been made to simulate a road cut slope in a landslide prone area in Rudrapryag, Uttarakhand, India which lies near Himalayan geodynamic mountain belt. A combination of Finite Element Method (FEM) and Artificial Neural Network (ANN) has been adopted to predict FOS of the slope. In ANN, a three layer, feed- forward back-propagation neural network with one input layer and one hidden layer with three neurons and one output layer has been considered and trained using datasets generated from numerical analysis of the slope and validated with new set of field slope data. Mean absolute percentage error estimated as 1.04 with coefficient of correlation between the FOS of FEM and ANN as 0.973, which indicates that the system is very vigorous and fast to predict FOS for any slope.

  20. Analysis of Rainfall Infiltration Law in Unsaturated Soil Slope

    Science.gov (United States)

    Zhang, Gui-rong; Qian, Ya-jun; Wang, Zhang-chun; Zhao, Bo

    2014-01-01

    In the study of unsaturated soil slope stability under rainfall infiltration, it is worth continuing to explore how much rainfall infiltrates into the slope in a rain process, and the amount of rainfall infiltrating into slope is the important factor influencing the stability. Therefore, rainfall infiltration capacity is an important issue of unsaturated seepage analysis for slope. On the basis of previous studies, rainfall infiltration law of unsaturated soil slope is analyzed. Considering the characteristics of slope and rainfall, the key factors affecting rainfall infiltration of slope, including hydraulic properties, water storage capacity (θ s - θ r), soil types, rainfall intensities, and antecedent and subsequent infiltration rates on unsaturated soil slope, are discussed by using theory analysis and numerical simulation technology. Based on critical factors changing, this paper presents three calculation models of rainfall infiltrability for unsaturated slope, including (1) infiltration model considering rainfall intensity; (2) effective rainfall model considering antecedent rainfall; (3) infiltration model considering comprehensive factors. Based on the technology of system response, the relationship of rainfall and infiltration is described, and the prototype of regression model of rainfall infiltration is given, in order to determine the amount of rain penetration during a rain process. PMID:24672332

  1. [Analysis of related factors of slope plant hyperspectral remote sensing].

    Science.gov (United States)

    Sun, Wei-Qi; Zhao, Yun-Sheng; Tu, Lin-Ling

    2014-09-01

    In the present paper, the slope gradient, aspect, detection zenith angle and plant types were analyzed. In order to strengthen the theoretical discussion, the research was under laboratory condition, and modeled uniform slope for slope plant. Through experiments we found that these factors indeed have influence on plant hyperspectral remote sensing. When choosing slope gradient as the variate, the blade reflection first increases and then decreases as the slope gradient changes from 0° to 36°; When keeping other factors constant, and only detection zenith angle increasing from 0° to 60°, the spectral characteristic of slope plants do not change significantly in visible light band, but decreases gradually in near infrared band; With only slope aspect changing, when the dome meets the light direction, the blade reflectance gets maximum, and when the dome meets the backlit direction, the blade reflectance gets minimum, furthermore, setting the line of vertical intersection of incidence plane and the dome as an axis, the reflectance on the axis's both sides shows symmetric distribution; In addition, spectral curves of different plant types have a lot differences between each other, which means that the plant types also affect hyperspectral remote sensing results of slope plants. This research breaks through the limitations of the traditional vertical remote sensing data collection and uses the multi-angle and hyperspectral information to analyze spectral characteristics of slope plants. So this research has theoretical significance to the development of quantitative remote sensing, and has application value to the plant remote sensing monitoring.

  2. Trunk and Shoulder Kinematic and Kinetic and Electromyographic Adaptations to Slope Increase during Motorized Treadmill Propulsion among Manual Wheelchair Users with a Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Dany Gagnon

    2015-01-01

    Full Text Available The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°. Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG of the pectoralis major (clavicular and sternal portions and deltoid (anterior and posterior fibers was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments.

  3. Lumbar sagittal contour after posterior interbody fusion: threaded devices alone versus vertical cages plus posterior instrumentation.

    Science.gov (United States)

    Klemme, W R; Owens, B D; Dhawan, A; Zeidman, S; Polly, D W

    2001-03-01

    An observational radiographic study examining lumbar sagittal contour of patients undergoing posterior interbody arthrodesis. To compare operative alterations of lumbar sagittal contour after posterior interbody fusion using threaded interbody devices alone versus vertical cages combined with posterior compression instrumentation. Technique-related alterations of lumbar sagittal contour during interbody arthrodesis have received little attention in the spinal literature. Standing lumbar radiographs were measured for preoperative and postoperative segmental lordosis at levels undergoing posterior interbody arthrodesis using either stand-alone side-by-side threaded devices or vertical cages combined with posterior transpedicular compression instrumentation. Sagittal plane segmental correction (or loss of correction) was calculated and statistically compared. The radiographs of 30 patients (34 spinal segments) undergoing lumbar or lumbosacral arthrodesis were compared. Seventeen patients (18 segments) had undergone interbody fusion using threaded cages,whereas 13 patients (16 segments) underwent fusion using vertically oriented mesh cages combined with posterior compression instrumentation. Preoperative segmental lordosis averaged 8 degrees for both groups. For patients undergoing fusion with threaded cages, there was a mean lordotic loss of 3 degrees/segment. For patients undergoing fusion with vertically oriented mesh cages combined with posterior compression instrumentation,there was a mean lordotic gain of 5 degrees/segment. This difference in segmental sagittal plane contour was highly significant (P = 0.00). Threaded fusion devices placed under interbody distraction with the endplates parallel fail to preserve or reestablish segmental lordosis. Vertical cages, however, when combined with posterior compression instrumentation, not only maintain segmental lordosis, but also can correct sagittal plane deformity.

  4. Thermal Properties of Alaskan North Slope Soils.

    Science.gov (United States)

    Overduin, P. P.; Kane, D. L.

    2002-12-01

    Climatic processes important to permafrost formation, maintenance and degradation have an annual to millennial timescale. The thin active layer, vegetation and snow above the permafrost can exert considerable influence on permafrost stability and react more rapidly than permafrost to climatic shifts. The thermal properties of this layer are thus important for the interpretation of permafrost data. We seek to predict bulk properties of a porous multiphase media based on state variables, bulk material properties and spatial phase densities. In this study, our objectives are: 1) to test thermal diffusivity probes in the field for the assessment of phase density, in particular of volumetric ice content and 2) to corroborate field studies with laboratory determinations of phase density and thermal diffusivity. We measure thermal properties and phase densities of a range of soils from the Alaskan North Slope, including high organic content and fine-grained mineral soils. Liquid water content is measured using time domain reflectometry to constrain the composition of the multiphase soil. Additional measurements of the soil's state are made using thermistors, heat flux plates and radial heat dissipation probes. The latter are thin films with embedded heat pulse wire and thermopiles to measure the radial thermal gradient response to temperature change. We report changes in thermal conductivity and diffusivity during freezing and thawing, and at different moisture contents and temperatures. The results for thermal conductivity and diffusivity as a function of phase density under field conditions are compared to those measured in the lab and to those calculated using empirical models.

  5. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    Directory of Open Access Journals (Sweden)

    Miquel Sureda-Gómez

    2015-11-01

    Full Text Available The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis.

  6. Posterior Wnts Have Distinct Roles in Specification and Patterning of the Planarian Posterior Region

    Science.gov (United States)

    Sureda-Gómez, Miquel; Pascual-Carreras, Eudald; Adell, Teresa

    2015-01-01

    The wnt signaling pathway is an intercellular communication mechanism essential in cell-fate specification, tissue patterning and regional-identity specification. A βcatenin-dependent signal specifies the AP (Anteroposterior) axis of planarians, both during regeneration of new tissues and during normal homeostasis. Accordingly, four wnts (posterior wnts) are expressed in a nested manner in central and posterior regions of planarians. We have analyzed the specific role of each posterior wnt and the possible cooperation between them in specifying and patterning planarian central and posterior regions. We show that each posterior wnt exerts a distinct role during re-specification and maintenance of the central and posterior planarian regions, and that the integration of the different wnt signals (βcatenin dependent and independent) underlies the patterning of the AP axis from the central region to the tip of the tail. Based on these findings and data from the literature, we propose a model for patterning the planarian AP axis. PMID:26556349

  7. Posterior Pole Sparing Laser Photocoagulation Combined with Intravitreal Bevacizumab Injection in Posterior Retinopathy of Prematurity

    Directory of Open Access Journals (Sweden)

    Rebecca Kim

    2014-01-01

    Full Text Available Purpose. To report the results of the posterior pole sparing laser photocoagulation combined with intravitreal bevacizumab injection (IVB in retinopathy of prematurity (ROP. Methods. A retrospective chart review of premature babies with ROP, all of whom received laser photocoagulation with IVB. Eleven eyes of 6 infants with advanced zone I ROP underwent laser ablation sparing posterior pole with concurrent IVB. The results were compared with those of full-laser treatment combined with IVB to 8 eyes of 5 infants with advanced ROP without involvement of the posterior pole. Results. The posterior pole sparing laser with IVB was performed with zone I, stage 3+ ROP at the mean postmenstrual age of 36 weeks and 5 days. The plus sign decreased significantly at postoperative day 1, the neovascular proliferation regressed by postoperative week 1, and the normal vascularization started at postoperative day 32 on the average. Two months after treatment, vascularization of the spared avascular area was completed. There was no macular dragging, tractional retinal detachment, foveal destruction by laser scars, or any other adverse event. No significant anatomical differences were identified from those of full-laser ablation combined with IVB. Conclusions. Posterior pole sparing laser with IVB can give favorable results without destruction of posterior pole retina.

  8. Hydrologic behavior of model slopes with synthetic water repellent soils

    Science.gov (United States)

    Zheng, Shuang; Lourenço, Sérgio D. N.; Cleall, Peter J.; Chui, Ting Fong May; Ng, Angel K. Y.; Millis, Stuart W.

    2017-11-01

    In the natural environment, soil water repellency decreases infiltration, increases runoff, and increases erosion in slopes. In the built environment, soil water repellency offers the opportunity to develop granular materials with controllable wettability for slope stabilization. In this paper, the influence of soil water repellency on the hydrological response of slopes is investigated. Twenty-four flume tests were carried out in model slopes under artificial rainfall; soils with various wettability levels were tested, including wettable (Contact Angle, CA 90°). Various rainfall intensities (30 mm/h and 70 mm/h), slope angles (20° and 40°) and relative compactions (70% and 90%) were applied to model the response of natural and man-made slopes to rainfall. To quantitatively assess the hydrological response, a number of measurements were made: runoff rate, effective rainfall rate, time to ponding, time to steady state, runoff acceleration, total water storage and wetting front rate. Overall, an increase in soil water repellency reduces infiltration and shortens the time for runoff generation, with the effects amplified for high rainfall intensity. Comparatively, the slope angle and relative compaction had only a minor contribution to the slope hydrology. The subcritical water repellent soils sustained infiltration for longer than both the wettable and water repellent soils, which presents an added advantage if they are to be used in the built environment as barriers. This study revealed substantial impacts of man-made or synthetically induced soil water repellency on the hydrological behavior of model slopes in controlled conditions. The results shed light on our understanding of hydrological processes in environments where the occurrence of natural soil water repellency is likely, such as slopes subjected to wildfires and in agricultural and forested slopes.

  9. Nitrogen isotopic composition of plants and soil in an arid mountainous terrain: south slope versus north slope

    Directory of Open Access Journals (Sweden)

    C. Chen

    2018-01-01

    Full Text Available Nitrogen cycling is tightly associated with environment. The south slope of a given mountain could significantly differ from north slope in environment. Thus, N cycling should also be different between the two slopes. Since leaf δ15N, soil δ15N and Δδ15Nleaf-soil (Δδ15Nleaf-soil =  leaf δ15N − soil δ15N could reflect the N cycling characteristics, we put forward a hypothesis that leaf δ15N, soil δ15N and Δδ15Nleaf-soil should differ between the two slopes. However, such a comparative study between two slopes has never been conducted. In addition, environmental effects on leaf and soil δ15N derived from studies at global scale were often found to be different from those on a regional scale. This led to our argument that environmental effects on leaf and soil δ15N could depend on local environment. To confirm our hypothesis and argument, we measured leaf and soil δ15N on the south and north slopes of Tian Shan. Remarkable environmental differences between the two slopes provided an ideal opportunity for our test. The study showed that leaf δ15N, soil δ15N and δ15Nleaf-soil on the south slope were greater than those on the north slope, although the difference in soil δ15N was not significant. The result confirmed our hypothesis and suggested that the south slope has higher soil N transformation rates and soil N availability than the north slope. In addition, in this study it was observed that the significant influential factors of leaf δ15N were temperature, precipitation, leaf N, leaf C ∕ N, soil moisture and silt ∕ clay ratio on the north slope, whereas on the south slope only leaf C ∕ N was related to leaf δ15N. The significant influential factors of soil δ15N were temperature, precipitation, soil moisture and silt ∕ clay ratio on the north slope, whereas on the south slope, mean annual precipitation and soil moisture exerted significant effects. Precipitation exerted contrary effects on soil

  10. IMPROVED LARGE-SCALE SLOPE ANALYSIS ON MARS BASED ON CORRELATION OF SLOPES DERIVED WITH DIFFERENT BASELINES

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2017-07-01

    Full Text Available The surface slopes of planetary bodies are important factors for exploration missions, such as landing site selection and rover manoeuvre. Generally, high-resolution digital elevation models (DEMs such as those generated from the HiRISE images on Mars are preferred to generate detailed slopes with a better fidelity of terrain features. Unfortunately, high-resolution datasets normally only cover small area and are not always available. While lower resolution datasets, such as MOLA, provide global coverage of the Martian surface. Slopes generated from the low-resolution DEM will be based on a large baseline and be smoothed from the real situation. In order to carry out slope analysis at large scale on Martian surface based low-resolution data such as MOLA data, while alleviating the smoothness problem of slopes due to its low resolution, this paper presents an amplifying function of slopes derived from low-resolution DEMs based on the relationships between DEM resolutions and slopes. First, slope maps are derived from the HiRISE DEM (meter-level resolution DEM generated from HiRISE images and a series of down-sampled HiRISE DEMs. The latter are used to simulate low-resolution DEMs. Then the high-resolution slope map is down- sampled to the same resolution with the slope map from the lower-resolution DEMs. Thus, a comparison can be conducted pixel-wise. For each pixel on the slope map derived from the lower-resolution DEM, it can reach the same value with the down-sampled HiRISE slope by multiplying an amplifying factor. Seven sets of HiRISE images with representative terrain types are used for correlation analysis. It shows that the relationship between the amplifying factors and the original MOLA slopes can be described by the exponential function. Verifications using other datasets show that after applying the proposed amplifying function, the updated slope maps give better representations of slopes on Martian surface compared with the original

  11. Nitrogen isotopic composition of plants and soil in an arid mountainous terrain: south slope versus north slope

    Science.gov (United States)

    Chen, Chongjuan; Jia, Yufu; Chen, Yuzhen; Mehmood, Imran; Fang, Yunting; Wang, Guoan

    2018-01-01

    Nitrogen cycling is tightly associated with environment. The south slope of a given mountain could significantly differ from north slope in environment. Thus, N cycling should also be different between the two slopes. Since leaf δ15N, soil δ15N and Δδ15Nleaf-soil (Δδ15Nleaf-soil = leaf δ15N - soil δ15N) could reflect the N cycling characteristics, we put forward a hypothesis that leaf δ15N, soil δ15N and Δδ15Nleaf-soil should differ between the two slopes. However, such a comparative study between two slopes has never been conducted. In addition, environmental effects on leaf and soil δ15N derived from studies at global scale were often found to be different from those on a regional scale. This led to our argument that environmental effects on leaf and soil δ15N could depend on local environment. To confirm our hypothesis and argument, we measured leaf and soil δ15N on the south and north slopes of Tian Shan. Remarkable environmental differences between the two slopes provided an ideal opportunity for our test. The study showed that leaf δ15N, soil δ15N and δ15Nleaf-soil on the south slope were greater than those on the north slope, although the difference in soil δ15N was not significant. The result confirmed our hypothesis and suggested that the south slope has higher soil N transformation rates and soil N availability than the north slope. In addition, in this study it was observed that the significant influential factors of leaf δ15N were temperature, precipitation, leaf N, leaf C / N, soil moisture and silt / clay ratio on the north slope, whereas on the south slope only leaf C / N was related to leaf δ15N. The significant influential factors of soil δ15N were temperature, precipitation, soil moisture and silt / clay ratio on the north slope, whereas on the south slope, mean annual precipitation and soil moisture exerted significant effects. Precipitation exerted contrary effects on soil δ15N between the two slopes. Thus, this study

  12. Giant nodular posterior scleritis simulating choroidal melanoma

    Directory of Open Access Journals (Sweden)

    Shukla Dhananjay

    2006-01-01

    Full Text Available A 45-year-old woman, complaining of sudden visual loss in the right eye (best-corrected visual acuity: 17/200, was suspected of having a malignant melanoma of the choroid. Fundus examination revealed a massive pale-colored subretinal mass temporal to the fovea, with adjoining choroidal folds and exudative retinal detachment. Ultrasonography was suggestive of posterior scleritis. Systemic evaluation was unremarkable. The patient was treated with high-dose systemic corticosteroids. The mass lesion resolved completely, with visual recovery to 20/20. Posterior scleritis should be suspected when evaluating subretinal mass-lesions, even when large and without overt inflammation. Early treatment may improve the visual prognosis and avoid misdirected management, including enucleation.

  13. Posterior reversible encephalopathy syndrome: A case report

    Directory of Open Access Journals (Sweden)

    Kostić Dejan

    2015-01-01

    Full Text Available Posterior reversible encephalopathy syndrome (PRES is characterized by the following symptoms: seizures, impaired consciousness and/or vision, vomiting, nausea, and focal neurological signs. Diagnostic imaging includes examination by magnetic resonance (MR and computed tomography (CT, where brain edema is visualized bi-laterally and symmetrically, predominantly posteriorly, parietally, and occipitally. Case report. We presented a 73-year-old patient with the years-long medical history of hipertension and renal insufficiency, who developed PRES with the symptomatology of the rear cranium. CT and MR verified changes in the white matter involving all lobes on both sides of the brain. After a two-week treatment (antihypertensive, hypolipemic and rehydration therapy clinical improvement with no complications occurred, with complete resolution of changes in the white matter observed on CT and MR. Conclusion. PRES is a reversible syndrome in which the symptoms withdraw after several days to several weeks if early diagnosis is made and appropriate treatment started without delay.

  14. Cervical subluxation associated with posterior cervical hemivertebra.

    Science.gov (United States)

    Otero-López, R; Rivero-Garvía, M; Márquez-Rivas, J; Valencia, J

    2016-02-01

    Hemivertebrae, associated with a failure in the formation and fusion of vertebral body ossification nuclei, are a common cause of thoracic or lumbar scoliosis. A cervical location is rare and even rarer as a cause of cervical subluxation in flexion and extension (for which only one previous case has been found). We report on the case of a 7-year-old female patient, who was examined for a cervical fusion defect, consisting of a posterior C4 hemivertebra and a left hemiblock from C5 to C7. After performing surgery consisting of a C4 corpectomy and anterior fixation with intersomatic graft and plate, adequate cervical stabilization with only a self-limiting left C6 brachialgia and ipsilateral Horner syndrome occurs in the postoperative period. Posterior cervical hemivertebra associated with instability is a very rare finding. The anterior approach with corpectomy and anterior plate enables suitable stabilization.

  15. Commercial possibilities for stranded conventional gas from Alaska's North Slope

    Science.gov (United States)

    Attanasi, E.D.; Freeman, P.A.

    2014-01-01

    Stranded gas resources are defined for this study as gas resources in discrete accumulations that are not currently commercially producible, or producible at full potential, for either physical or economic reasons. Approximately 35 trillion cubic feet (TCF) of stranded gas was identified on Alaska’s North Slope. The commercialization of this resource requires facilities to transport gas to markets where sales revenue will be sufficient to offset the cost of constructing and operating a gas delivery system. With the advent of the shale gas revolution, plans for a gas pipeline to the conterminous US have been shelved (at least temporarily) and the State and resource owners are considering a liquefied natural gas (LNG) export project that targets Asian markets. This paper focuses on competitive conditions for Asian gas import markets by estimating delivered costs of competing supplies from central Asia, Russia, Indonesia, Malaysia, and Australia in the context of a range of import gas demand projections for the period from 2020 to 2040. These suppliers’ costs are based on the cost of developing, producing, and delivering to markets tranches of the nearly 600 TCF of recoverable gas from their own conventional stranded gas fields. The results of these analyses imply that Alaska’s gas exports to Asia will likely encounter substantial competitive challenges. The sustainability of Asia’s oil-indexed LNG pricing is also discussed in light of a potentially intense level of competition.

  16. Primary posterior perineal herniation of urinary bladder

    Directory of Open Access Journals (Sweden)

    Kurumboor Prakash

    2013-01-01

    Full Text Available Primary perineal hernia is a rare clinical condition wherein herniation of viscera occurs through pelvic diaphragm. They are usually mistaken for sciatic hernia, rectal prolapse or other diseases in the perineum. Correct identification of the type of hernia by imaging is crucial for planning treatment. We present a case of primary posterior herniation of urinary bladder and rectal wall through levator ani repaired laparoscopically using a mesh repair.

  17. 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.

  18. Reversible posterior leukoencephalopathy after combination chemotherapy

    International Nuclear Information System (INIS)

    Honkaniemi, J.; Latvala, M.; Hietaharju, A.; Ollikainen, J.; Vaehaemaeki, L.; Frey, H.; Kaehaerae, V.; Dastidar, P.; Salonen, T.; Keskinen, L.; Kellokumpu-Lehtinen, P.

    2000-01-01

    We describe a young woman with Burkitt's lymphoma, treated with intravenous adriamycine and cyclophosphamide and intrathecal cytarabine. She developed a reversible posterior leukoencephalopathy syndrome (RPLS) with typical MRI findings. Diffusion-weighted images during the first days after the onset of symptoms predicted a small irreversible lesion in the frontal lobe, verified on T2-weighted images 1 month later. The patient showed full recovery after high-dose steroid treatment. (orig.)

  19. Indirect posterior composite inlays and onlays.

    Science.gov (United States)

    Landman, P

    1994-01-01

    Indirect posterior composite inlays and onlays are a valuable part of the cosmetic dentist's repertoire of services. They fulfill most of the requirements for an esthetic alternative to the previously considered amalgam, gold, porcelain, and directly placed composite restorations. As in all other cosmetic dental procedures, attention to detail is essential for success. Improving technology will continue to have an impact on the place these restorations occupy in future cosmetic practice.

  20. CT in thrombosed dilated posterior epidural vein

    Energy Technology Data Exchange (ETDEWEB)

    Bammatter, S.; Schnyder, P.; Preux, J. de

    1987-05-01

    The authors report a case of thrombosis of the distal end of an enlarged right posterior epidural vein. The patient had a markedly narrow lumbar canal due to L5 spondylolisthesis. The dilated vein and the thrombosis were displayed by computed tomography but remained unrecognized until surgery. Pathogenesis of this condition is discussed. A review of the English, French and German literature revealed no prior radiological reports of a similar condition.

  1. Cyclosporine-related reversible posterior leukoencephalopathy: MRI

    International Nuclear Information System (INIS)

    Jarosz, J.M.; Howlett, D.C.; Cox, T.C.S.; Bingham, J.B.

    1997-01-01

    Three patients aged 48, 11 and 40 years, two of whom were recent recipients of renal transplants and one of a bone marrow transplant, developed seizures, with cortical blindness in two cases. All were immunosuppressed with cyclosporine and were hypertensive at the onset of symptoms. MRI showed predominantly posterior signal changes in all three cases. The abnormalities were more conspicuous on fast FLAIR images than on conventional T2-weighted spin-echo images. (orig.). With 4 figs

  2. Cervical disc hernia operations through posterior laminoforaminotomy.

    Science.gov (United States)

    Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

    2016-01-01

    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. 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. 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. Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  3. Bayesian Posterior Distributions Without Markov Chains

    OpenAIRE

    Cole, Stephen R.; Chu, Haitao; Greenland, Sander; Hamra, Ghassan; Richardson, David B.

    2012-01-01

    Bayesian posterior parameter distributions are often simulated using Markov chain Monte Carlo (MCMC) methods. However, MCMC methods are not always necessary and do not help the uninitiated understand Bayesian inference. As a bridge to understanding Bayesian inference, the authors illustrate a transparent rejection sampling method. In example 1, they illustrate rejection sampling using 36 cases and 198 controls from a case-control study (1976–1983) assessing the relation between residential ex...

  4. Posterior midline cervical fetal cystic hygroma.

    Directory of Open Access Journals (Sweden)

    Oak S

    1992-04-01

    Full Text Available Posterior midline cervical cystic hygromas (PMC are frequently found associated with chromosomal aberrations and usually do not survive. The present report illustrates diagnosis of this condition by sonography in an 18 weeks old fetus and an amniocentesis revealed 45 x0 karyotype and increased concentration of alpha-fetoproteins. Pregnancy was terminated in view of Turner′s syndrome. The etiology and natural history of the condition is reviewed.

  5. Posterior sternoclavicular dislocation: an American football injury

    DEFF Research Database (Denmark)

    Marker, L B; Klareskov, B

    1996-01-01

    Posterior dislocation of the sternoclavicular joint is uncommon, accounting for less than 0.1% of all dislocations. Since 1824 a little more than 100 cases have been reported, and the majority in the past 20 years. A review of published reports suggests that this injury is seen particularly in co...... in connection with American football. A typical case is described. The importance of this injury is that there is often a delay in diagnosis with potentially serious complications....

  6. Degradation of terraced slopes in Mediterranean conditions

    Science.gov (United States)

    Tsermegas, I.; DłuŻewski, M.; Biejat, K.; Szynkiewicz, A.

    2012-04-01

    Agricultural terraces with dry-stone walls take the largest area of all man-made landforms in Mediterranean mountain regions. Despite on that their contemporary morphodynamics have not been the subject of many studies. It is a significant problem both from a scientific and a practical point of view. The aim of the study was to estimate the influence of relief, lithology, climatic conditions, methods of wall construction and actual agricultural practice on the degradation of agricultural terraces. A field study was conducted in Greece on 7 plots with the overall area of over 42 000 m2 - on the east Crete and on two Aegean islands - Ikaria and Thera. The analysis was conducted on terraced slopes with gradient of 8-23o, built of granitoids, gneisses, crystalline schists, limestones, crystalline dolomites and volcanic tuffs. There was identified the types of terrace walls. Metrical features of terrace systems were ascertained on the basis of GPS RTK measurement. Terrace material petrography and grain size distribution was identified for regolith an soil samples taken from the selected outcrops which were recognized as being representative for 239 georadar profiles of the joint length of over 2500 m. On that basis the volume of each terrace material was defined. The rills cutting the fields and the walls were measured. The infiltration rate was also taken in 130 points. Reasearch showed that regardless of metrical features of terraces, soil grain size distribution and thickness of the terrace material, the most important reason for the destruction of terrace walls is the abandonment of cultivated areas. Changes in cultivation methods and the introduction of pasturage visibly accelerate the degradation processes. On areas unused for 30 years terrace walls are destroyed on over 25% of their length. It concerns both the areas on which filtration coefficient (k) reaches about 10-5m•s-1 as well as the ones where it is a 100 times lower. The least varied values (10-6-10-5m

  7. "A Comparison of Several Methods in a Rock Slope Stability ...

    African Journals Online (AJOL)

    This researchuses the mentioned methods and principles in the stability analysis of some rock slopes in an open pit mine in Syria, that is Khneifees phosphate mine. The importance of this researchis that it shows the role of kinematical analysis in minimizing efforts when verifying the safety of rock slopes in site, and when ...

  8. After the Slippery Slope: Dutch Experiences on Regulating Active Euthanasia

    NARCIS (Netherlands)

    Boer, Th.A.

    2003-01-01

    “When a country legalizes active euthanasia, it puts itself on a slippery slope from where it may well go further downward.” If true, this is a forceful argument in the battle of those who try to prevent euthanasia from becoming legal. The force of any slippery-slope argument, however, is by

  9. assessment of slope stability around gilgel gibe-ii hydroelectric

    African Journals Online (AJOL)

    preferred customer

    ... are steep and valleys are deep with low vegetation cover. Along the road from Fofa town to powerhouse II, the slope cuts are steep, which overhang at places. Thus, an attempt has been made to analyze the stability condition of potential unstable slopes along the road between Fofa town and Gilgel-Gibe Hydro- power II.

  10. Preliminary Analysis of Slope Stability in Kuok and Surrounding Areas

    Directory of Open Access Journals (Sweden)

    Dewandra Bagus Eka Putra

    2016-12-01

    Full Text Available The level of slope influenced by the condition of the rocks beneath the surface. On high level of slopes, amount of surface runoff and water transport energy is also enlarged. This caused by greater gravity, in line with the surface tilt from the horizontal plane. In other words, topsoil eroded more and more. When the slope becomes twice as steep, then the amount of erosion per unit area be 2.0 - 2.5 times more. Kuok and surrounding area is the road access between the West Sumatra and Riau which plays an important role economies of both provinces. The purpose of this study is to map the locations that have fairly steep slopes and potential mode of landslides. Based on SRTM data obtained,  the roads in Kuok area has a minimum elevation of + 33 m and a maximum  + 217.329 m. Rugged road conditions with slope ranging from 24.08 ° to 44.68 ° causing this area having frequent landslides. The result of slope stability analysis in a slope near the Water Power Plant Koto Panjang, indicated that mode of active failure is toppling failure or rock fall and the potential zone of failure is in the center part of the slope.

  11. RMS slope of exponentially correlated surface roughness for radar applications

    DEFF Research Database (Denmark)

    Dierking, Wolfgang

    2000-01-01

    In radar signature analysis, the root mean square (RMS) surface slope is utilized to assess the relative contribution of multiple scattering effects. For an exponentially correlated surface, an effective RMS slope can be determined by truncating the high frequency tail of the roughness spectrum...

  12. Slope Monitoring using Total Station: What are the Challenges and ...

    African Journals Online (AJOL)

    ... survey perspective on the typical problems that can be expected during slope monitoring using total station (also known as prism monitoring) and second, to suggest ways of mitigating such problems. The aim is to create awareness of the implications of incorrect use or negligence during slope monitoring surveys utilising ...

  13. Effects of slope position and fertilization on the performance of ...

    African Journals Online (AJOL)

    FARO 45 (ITA 257) early maturing upland variety of rice was used as the test crop at each slope level. The experiment was a 3 x 2 factorial combination of three slopes (upper, middle and hydromorphic fringe) and two fertilizations (without fertilizer and with fertilizer) in a Randomized Complete Block Design (RCBD), ...

  14. Assessment of slope stability and remedial measures around Gilgel ...

    African Journals Online (AJOL)

    (1995) technique, whereas the slope having wedge mode of failure was analyzed by 'SASW' computer program. The stability analysis was carried out for the existing and anticipated worst conditions. The results indicate that all critical slopes in the study area are stable for the existing conditions, represented by dry static ...

  15. Assessment of rock mass decay in artificial slopes

    NARCIS (Netherlands)

    Huisman, M.

    2006-01-01

    This research investigates the decay of rock masses underlying slopes, and seeks to quantify the relations of such decay with time and geotechnical parameters of the slope and rock mass. Decay can greatly affect the geotechnical properties of rocks within engineering timescales, and may induce a

  16. Analysis of Covariance and Randomized Block Design with Heterogeneous Slopes.

    Science.gov (United States)

    Klockars, Alan J.; Beretvas, S. Natasha

    2001-01-01

    Compared the Type I error rate and the power to detect differences in slopes and additive treatment effects of analysis of covariance (ANCOVA) and randomized block designs through a Monte Carlo simulation. Results show that the more powerful option in almost all simulations for tests of both slope and means was ANCOVA. (SLD)

  17. Slope Monitoring using Total Station: What are the Challenges and ...

    African Journals Online (AJOL)

    Afeni

    implications of incorrect use or negligence during slope monitoring surveys utilising a total station. 1. Introduction ... monitoring frequency depends on the nature of the rock type, operations around the slope and the objectives of ... to do with correct design, legal compliance, monitoring requirements and systems design that.

  18. Morphologic, Topographic, and Thermal Analysis of Slope Streaks on Mars

    Science.gov (United States)

    Aharonson, O.; Schorghofer, N.; Khatiwala, S.; Richardson, M. I.

    2002-12-01

    Surfaces containing features known as slope streaks are common on Mars in regions where thermal-inertia is low and steep slopes are frequent. We have recently compiled a catalog of slope streak images and identified previously unrecognized correlations with surface properties. Building on this work, we analyze data from Mars Orbiter Camera, from Mars Orbiter Laser Altimeter, and from the Thermal Emission Imaging System instrument on board Mars Odyssey, to constrain the physical properties and thermal conditions at the specific sites where slope streaks are forming. A number of proposed theories explaining the formation mechanism of slope streaks can be tested using new data, including an exciting possibility of the potential role of a water phase-transition.

  19. US North Slope gas and Asian LNG markets

    Science.gov (United States)

    Attanasi, E.D.

    1994-01-01

    Prospects for export of liquified natural gas (LNG) from Alaska's North Slope are assessed. Projected market conditions to 2010 show that new LNG capacity beyond announced expansions will be needed to meet regional demand and that supplies will probably come from outside the region. The estimated delivered costs of likely suppliers show that Alaska North Slope gas will not be competitive. The alternative North Slope gas development strategies of transport and sale to the lower 48 states and use on the North Slope for either enhanced oil recovery or conversion to liquids are examined. The alternative options require delaying development until US gas prices increase, exhaustion of certain North Slope oil fields, or advances occur in gas to liquid fuels conversion technology. ?? 1995.

  20. Determination Of Slope Instability Using Spatially Integrated Mapping Framework

    Science.gov (United States)

    Baharuddin, I. N. Z.; Omar, R. C.; Roslan, R.; Khalid, N. H. N.; Hanifah, M. I. M.

    2016-11-01

    The determination and identification of slope instability are often rely on data obtained from in-situ soil investigation work where it involves the logistic of machineries and manpower, thus these aspects may increase the cost especially for remote locations. Therefore a method, which is able to identify possible slope instability without frequent ground walkabout survey, is needed. This paper presents the method used in prediction of slope instability using spatial integrated mapping framework which applicable for remote areas such as tropical forest and natural hilly terrain. Spatial data such as geology, topography, land use map, slope angle and elevation were used in regional analysis during desktop study. Through this framework, the occurrence of slope instability was able to be identified and was validate using a confirmatory site- specific analysis.

  1. Convergence of posteriors for discretized log Gaussian Cox processes

    DEFF Research Database (Denmark)

    Waagepetersen, Rasmus Plenge

    2004-01-01

    In Markov chain Monte Carlo posterior computation for log Gaussian Cox processes (LGCPs) a discretization of the continuously indexed Gaussian field is required. It is demonstrated that approximate posterior expectations computed from discretized LGCPs converge to the exact posterior expectations...... when the cell sizes of the discretization tends to zero. The effect of discretization is studied in a data example....

  2. Topography of The Posterior Communicating Artery in a Kenyan ...

    African Journals Online (AJOL)

    pattern of the posterior communication artery in a Kenyan population. Materials and Methods. Eighty four posterior communicating arteries obtained from Depart- ment of Human Anatomy were studied. The configuration and number of branches in each third and length of the longest perforator free zone of the posterior ...

  3. Radiographic Restoration of Sagittal Spinopelvic Alignment After Posterior Lumbar Interbody Fusion in Degenerative Spondylolisthesis.

    Science.gov (United States)

    Kong, Ling-De; Zhang, Ying-Ze; Wang, Feng; Kong, Fan-Long; Ding, Wen-Yuan; Shen, Yong

    2016-03-01

    A retrospective study. This study was aimed to analyze the changes in spinopelvic parameters after surgical correction of degenerative spondylolisthesis and to determine which deformity is most responsible for changes in sagittal spinopelvic alignment. The basic deformities of degenerative spondylolisthesis are forward slippage of the vertebral body, segmental kyphotic angle, and loss of disk height. Correction of those deformities during surgery will subsequently affect the spinopelvic parameters. A few studies have reported the changes of sagittal spinopelvic alignment after surgical treatment of isthmic spondylolisthesis. However, there appears to be relatively little information regarding degenerative spondylolisthesis. Fifty-three patients with L4-L5 degenerative spondylolisthesis were included. All patients underwent posterior lumbar interbody fusion and posterior instrumentation. Back pain, as the clinical outcome, was evaluated by visual analogue scale (VAS). The preoperative and postoperative spinopelvic parameters, including sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL), and L1 axis S1 distance were measured, and then the correlations between spinopelvic parameters and local deformity parameters such as slip degree, slip angle (SA), and height of the intervertebral disk were evaluated. After surgical correction of local deformity, all spinopelvic parameters changed subsequently: PT and L1 axis S1 distance had a decrease, SS and LL had an increase. VAS score decreased from 6.1±2.3 before surgery to 2.4±1.7 at the final follow-up assessment. Patients with VAS score changes ≥3 showed significantly higher SS and LL, and lower PT compared with those with VAS score changes spondylolisthesis with posterior lumbar interbody fusion and posterior instrumentation resulted in relief of back pain, which may be associated with improvement of sagittal spinopelvic alignment. Surgeons should consider deformity parameters, especially the SA, in the surgical

  4. Slope mass rating and kinematic analysis of slopes along the national highway-58 near Jonk, Rishikesh, India

    Directory of Open Access Journals (Sweden)

    Tariq Siddique

    2015-10-01

    Full Text Available The road network in the Himalayan terrain, connecting remote areas either in the valleys or on the hill slopes, plays a pivotal role in socio-economic development of India. The planning, development and even maintenance of road and rail networks in such precarious terrains are always a challenging task because of complexities posed by topography, geological structures, varied lithology and neotectonics. Increasing population and construction of roads have led to destabilisation of slopes, thus leading to mass wasting and movement, further aggravation due to recent events of cloud bursts and unprecedented flash floods. Vulnerability analysis of slopes is an important component for the “Landslide Hazard Assessment” and “Slope Mass Characterisation” guide planners to predict and choose suitable ways for construction of roads and other engineering structures. The problem of landslides along the national highway-58 (NH-58 from Rishikesh to Devprayag is a common scene. The slopes along the NH-58 between Jonk and Rishikesh were investigated, which experienced very heavy traffic especially from March to August due to pilgrimage to Kedarnath shrine. On the basis of slope mass rating (SMR investigation, the area falls in stable class, and landslide susceptibility score (LSS values also indicate that the slopes under investigation fall in low to moderate vulnerability to landslide. More attentions should be paid to the slopes to achieve greater safe and economic benefits along the highway.

  5. Effect of slope height and horizontal forces on the bearing capacity of strip footings near slopes in cohesionless soil

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Damkilde, Lars; Krabbenhøft, Kristian

    2016-01-01

    The problem of determining the bearing capacity of a strip foundation located near a slope of infinite height has been dealt with by several authors. Very often in practical problems the slope is of limited height, and furthermore the resulting load may be inclined at an angle to the horizontal, ...

  6. Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

    Science.gov (United States)

    Török, Ákos; Barsi, Árpád; Bögöly, Gyula; Lovas, Tamás; Somogyi, Árpád; Görög, Péter

    2018-02-01

    Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE-WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).

  7. Slope stability and rockfall assessment of volcanic tuffs using RPAS with 2-D FEM slope modelling

    Directory of Open Access Journals (Sweden)

    Á. Török

    2018-02-01

    Full Text Available Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System was used to collect images which were processed by Pix4D mapper (structure from motion technology to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS with the use of seven ground control points. The obtained digital surface model (DSM was processed (vegetation removal and the derived digital terrain model (DTM allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method. Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE–WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS.

  8. Is there a distinct continental slope fauna in the Antarctic?

    Science.gov (United States)

    Kaiser, Stefanie; Griffiths, Huw J.; Barnes, David K. A.; Brandão, Simone N.; Brandt, Angelika; O'Brien, Philip E.

    2011-02-01

    The Antarctic continental slope spans the depths from the shelf break (usually between 500 and 1000 m) to ˜3000 m, is very steep, overlain by 'warm' (2-2.5 °C) Circumpolar Deep Water (CDW), and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the abyssal fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell Sea and Scotia Sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III, BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ (Ecology of the Antarctic Sea Ice Zone) II cruises as well as current databases (SOMBASE, SCAR-MarBIN), four different taxa were selected (i.e. cheilostome bryozoans, isopod and ostracod crustaceans and echinoid echinoderms) and two areas, the Weddell Sea and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations. Benthic samples were collected using Agassiz trawl, epibenthic sledge and Rauschert sled. By bathymetric definition, these data suggest that despite eurybathy in some of the groups examined and apparent similarity of physical conditions in the Antarctic, the shelf, slope and abyssal faunas were clearly separated in the Weddell Sea. However, no such separation of faunas was apparent in the Scotia Sea (except in echinoids). Using a geomorphological definition of the slope, shelf-slope-abyss similarity only changed significantly in the bryozoans. Our results did not support the presence of a homogenous and unique Antarctic slope fauna despite a high number of species being restricted to the slope. However, it remains the case that there may be

  9. Study on the response of unsaturated soil slope based on the effects of rainfall intensity and slope angle

    Science.gov (United States)

    Ismail, Mohd Ashraf Mohamad; Hamzah, Nur Hasliza

    2017-07-01

    Rainfall has been considered as the major cause of the slope failure. The mechanism leading to slope failures included the infiltration process, surface runoff, volumetric water content and pore-water pressure of the soil. This paper describes a study in which simulated rainfall events were used with 2-dimensional soil column to study the response of unsaturated soil behavior based on different slope angle. The 2-dimensional soil column is used in order to demonstrate the mechanism of the slope failure. These unsaturated soil were tested with four different slope (15°, 25°, 35° and 45°) and subjected to three different rainfall intensities (maximum, mean and minimum). The following key results were obtained: (1) the stability of unsaturated soil decrease as the rainwater infiltrates into the soil. Soil that initially in unsaturated state will start to reach saturated state when rainwater seeps into the soil. Infiltration of rainwater will reduce the matric suction in the soil. Matric suction acts in controlling soil shear strength. Reduction in matric suction affects the decrease in effective normal stress, which in turn diminishes the available shear strength to a point where equilibrium can no longer be sustained in the slope. (2) The infiltration rate of rainwater decreases while surface runoff increase when the soil nearly achieve saturated state. These situations cause the soil erosion and lead to slope failure. (3) The steepness of the soil is not a major factor but also contribute to slope failures. For steep slopes, rainwater that fall on the soil surface will become surface runoff within a short time compare to the water that infiltrate into the soil. While for gentle slopes, water that becomes surface runoff will move slowly and these increase the water that infiltrate into the soil.

  10. Martian slope streaks as plausible indicators of transient water activity.

    Science.gov (United States)

    Bhardwaj, Anshuman; Sam, Lydia; Martín-Torres, F Javier; Zorzano, María-Paz; Fonseca, Ricardo M

    2017-08-01

    Slope streaks have been frequently observed in the equatorial, low thermal inertia and dusty regions of Mars. The reason behind their formation remains unclear with proposed hypotheses for both dry and wet mechanisms. Here, we report an up-to-date distribution and morphometric investigation of Martian slope streaks. We find: (i) a remarkable coexistence of the slope streak distribution with the regions on Mars with high abundances of water-equivalent hydrogen, chlorine, and iron; (ii) favourable thermodynamic conditions for transient deliquescence and brine development in the slope streak regions; (iii) a significant concurrence of slope streak distribution with the regions of enhanced atmospheric water vapour concentration, thus suggestive of a present-day regolith-atmosphere water cycle; and (iv) terrain preferences and flow patterns supporting a wet mechanism for slope streaks. These results suggest a strong local regolith-atmosphere water coupling in the slope streak regions that leads to the formation of these fluidised features. Our conclusions can have profound astrobiological, habitability, environmental, and planetary protection implications.

  11. Soil erosion processes on sloping land using REE tracer

    International Nuclear Information System (INIS)

    Shen Zhenzhou; Liu Puling; Yang Mingyi; Lian Zhenlong; Ju Tongjun; Yao Wenyi; Li Mian

    2007-01-01

    Sheet erosion is the main performance in the slope soil erosion process at the primary stage of natural rainfall. For three times of rainfall during experiment, the ratios of sheet erosion to total erosion account for 71%, 48% and 49% respectively, which showed that the sloping erosion was still at the primary stage from sheet erosion to rill erosion. With the rainfall going, the rill erosion amount increase. It showed that soil erosion was changing from sheet erosion to rill erosion. The sources of sediment from different sections of the plot were analyzed, and the results indicated that whatever the sheet erosion changed, the ratio erosion of upper part of surface soil was always lower than 10%. Sheet erosion came mainly from the lower section of surface soil. With the ratios to the amount of total rill erosion changes, the rill erosion amount of each section regularly changes too. The general conclusion is that when the rainfall ends, relative erosion of different slope element to the foot of slope is: 1 meter away accounts for 16%, 2-4 meters away is 6% and 5-9 meters away is 3%. The ratio of rill erosion amount of these three slope element is 5:2:1, which shows the rill erosion amount are mainly from the slope element of 4 meters from the foot of slope. (authors)

  12. Posterior ventricular anchoring neochordal repair of degenerative mitral regurgitation efficiently remodels and repositions posterior leaflet prolapse†

    Science.gov (United States)

    Woo, Y. Joseph; MacArthur, John W.

    2013-01-01

    OBJECTIVES Mitral valve repair techniques for degenerative disease typically entail leaflet resection or neochordal construction, which may require extensive resection, leaflet detachment/reattachment, reliance on diseased native chords or precise neochordal measuring. Occasionally, impaired leaflet mobility, reduced coaptation surface and systolic anterior motion (SAM) may result. We describe a novel technique for addressing posterior leaflet prolapse/flail, which both simplifies repair and addresses these issues. METHODS Fifty-four patients (age 62 ± 11 years) with degenerative MR underwent this new repair, 36 of whom minimally-invasively. A CV5 Gore-Tex suture was placed into the posterior left ventricular myocardium underneath the prolapsing segment as an anchor. This suture was then used to imbricate a portion of the prolapsed segment into the ventricle, creating a smooth, broad, non-prolapsed coapting surface on a leaflet with preserved mobility, additional neochordal support and posteriorly positioned enough to preclude SAM. RESULTS Repair was successful in all patients. The mean MR grade was reduced from +3.8 to +0.1 with 50 of 54 patients having zero MR and 4 of the 54 having trace or mild MR. All patients had proper antero-posterior location of the coaptation line of a mean length of 10.2 mm, and preserved posterior leaflet mobility. No patients had SAM or mitral stenosis. All patients were discharged and are currently doing well. CONCLUSION This new technique facilitated efficient single-suture repair of the prolapsed posterior leaflet mitral regurgitation without the need for resection or sliding annuloplasty. It precluded the need for precise neochordal measurement and preserved the leaflet coaptation surface. PMID:23449863

  13. MRI of the fetal posterior fossa

    Energy Technology Data Exchange (ETDEWEB)

    Adamsbaum, Catherine; Andre, Christine; Merzoug, Valerie; Ferey, Solene [St Vincent de Paul Hospital, Department of Radiology, Paris Cedex 14 (France); Moutard, Marie Laure [St Vincent de Paul Hospital, Department of Neuropaediatrics, Paris (France); Quere, Marie Pierre [CHU, Department of Radiology, Nantes (France); Lewin, Fanny [St Vincent de Paul Hospital, Maternity Department, Paris (France); Fallet-Bianco, Catherine [Ste Anne Hospital, Department of Neuropathology, Paris (France)

    2005-02-01

    MRI is a useful tool to complement US for imaging of the fetal posterior fossa (PF). In France, the discovery of a PF malformation in the fetus frequently leads to termination of pregnancy (80% in a personal series). However, despite improved accuracy in the diagnosis of PF abnormalities, prognosis remains uncertain. The first objective of this review is to document the normal MRI landmarks of the developing fetal PF. Because of their thinness, the visibility of the cerebellar fissures is dramatically delayed on MRI compared to macroscopic data. An important landmark is identification of the primary fissure of the vermis, normally seen at around 25-26 weeks' gestation (WG) on the sagittal slice, separating the larger posterior lobe from the anterior lobe (volume ratio around 2:1). The prepyramidal and secondary fissures are usually only identifiable after 32 WG and the hemispheric fissures are difficult to see until the end of pregnancy. Considering the signal changes, high signal on T2-weighted (T2-W) sequences is seen from 25 WG in the posterior part of the brain stem (tegmentum and ascending sensory tracts) related to myelination. The low signal intensities seen within the cerebellum on T2-W images correspond to high cellularity of grey matter (deep nuclei), as there is no myelination within the white matter before 38 WG. The second objective is to highlight the signs highly predictive of a poor neurological prognosis. Lack of pontine curvature or vermian agenesis without a PF cyst (small volume of PF) is greatly associated with poor neurological status. The third objective is to propose a diagnostic strategy in difficult cases where prognosis is important, e.g. the Dandy Walker continuum. (orig.)

  14. MRI of the fetal posterior fossa

    International Nuclear Information System (INIS)

    Adamsbaum, Catherine; Andre, Christine; Merzoug, Valerie; Ferey, Solene; Moutard, Marie Laure; Quere, Marie Pierre; Lewin, Fanny; Fallet-Bianco, Catherine

    2005-01-01

    MRI is a useful tool to complement US for imaging of the fetal posterior fossa (PF). In France, the discovery of a PF malformation in the fetus frequently leads to termination of pregnancy (80% in a personal series). However, despite improved accuracy in the diagnosis of PF abnormalities, prognosis remains uncertain. The first objective of this review is to document the normal MRI landmarks of the developing fetal PF. Because of their thinness, the visibility of the cerebellar fissures is dramatically delayed on MRI compared to macroscopic data. An important landmark is identification of the primary fissure of the vermis, normally seen at around 25-26 weeks' gestation (WG) on the sagittal slice, separating the larger posterior lobe from the anterior lobe (volume ratio around 2:1). The prepyramidal and secondary fissures are usually only identifiable after 32 WG and the hemispheric fissures are difficult to see until the end of pregnancy. Considering the signal changes, high signal on T2-weighted (T2-W) sequences is seen from 25 WG in the posterior part of the brain stem (tegmentum and ascending sensory tracts) related to myelination. The low signal intensities seen within the cerebellum on T2-W images correspond to high cellularity of grey matter (deep nuclei), as there is no myelination within the white matter before 38 WG. The second objective is to highlight the signs highly predictive of a poor neurological prognosis. Lack of pontine curvature or vermian agenesis without a PF cyst (small volume of PF) is greatly associated with poor neurological status. The third objective is to propose a diagnostic strategy in difficult cases where prognosis is important, e.g. the Dandy Walker continuum. (orig.)

  15. SINDROME DE COLAPSO DE MORDIDA POSTERIOR

    Directory of Open Access Journals (Sweden)

    Paula Alejandra Baldión

    2012-12-01

    Full Text Available El Síndrome de Colapso de Mordida posterior es una patología oclusal que se presenta como consecuencia de problemas dentales, periodontales y oclusales, que exige la correcta evaluación de los signos y síntomas que lo caracterizan.  El objetivo del artículo es describir la manera como evoluciona la enfermedad, la evaluación multidisciplinaria para obtener un diagnóstico preciso y la secuencia de tratamiento integral, revisando los conceptos para un mejor entendimiento del tratamiento periodontal y restaurativo que requieren los pacientes con síndrome de colapso de mordida posterior; caracterizado por procesos patológicos como enfermedad periodontal, caries dental con subsecuente alteración de la integridad del arco dentario que genera perdida de soporte posterior conllevando a un trauma oclusal secundario y disminución de la dimensión vertical oclusal. El control del proceso inflamatorio y la estabilización periodontal son puntos de partida indispensables en el tratamiento integral del paciente. La migración patológica de los dientes y las alteraciones del plano oclusal pueden exigir la corrección ortodóntica de los arcos y en algunos casos el concurso de cirugía oral para la nivelación del plano oclusal. La secuencia organizada del tratamiento por fases permite la restauración predecible de los pacientes con este síndrome, tomando en cuenta las diferentes alternativas protésicas tanto removibles como fijas con o sin implantes de oseointegración, para el éxito integral a largo plazo.

  16. Posterior surgery in high-grade spondylolisthesis.

    Science.gov (United States)

    Lengert, R; Charles, Y P; Walter, A; Schuller, S; Godet, J; Steib, J-P

    2014-09-01

    High-grade L5-S1 spondylolisthesis alters sagittal spinopelvic balance, which can cause low back pain and progressive neurologic disorder. The present study assessed spondylolisthesis reduction and maintenance over time with L4-S1 versus L5-S1 fusion using a lever-arm system and posterior fusion combined with lumbosacral graft. Forty patients were operated on for symptomatic high-grade spondylolisthesis, 34 of whom had full pre- and post-operative radiological analysis, with a mean follow-up of 5.4years. There were 9 L5-S1 and 25 L4-S1 instrumentations. Analysis of spinopelvic and slipping parameters and the evolution of segmental lordosis compared results between L5-S1 and L4-S1 instrumentation. Mean Taillard spondylolisthesis index decreased from 64% to 37% (P=0.0001). Overall sagittal spinopelvic balance was not significantly changed. Overall L1-S1 and segmental L4-L5 lordosis were not affected by instrumentation. Mean L5-S1 segmental lordosis increased from 11° to 18°. There was loss of reduction from 19° to 14° with L5-S1 instrumentation, in contrast to maintained reduction with L4-S1 instrumentation (P=0.006). The lever-arm system provided anterior-posterior reduction of spondylolisthesis and corrected slippage. Postoperative change in overall sagittal spinopelvic balance was slight and constant. Posterior L4-S1 fusion provided better long-term control of L5-S1 lordosis reduction than the shorter L5-S1 fusion. Retrospective study of level IV. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. Post-partum posterior reversible encephalopathy syndrome

    DEFF Research Database (Denmark)

    Aaen, Anne Albers; Jeppesen, Jørgen; Obaid, Hayder

    2015-01-01

    Posterior reversible encephalopathy syndrome (PRES) is a complex clinical condition with vasogenic subcortical oedema caused by hypertension. Oedema is often seen on magnetic resonance imaging. The wide clinical spectrum ranges from headaches to vision loss and even death. Early diagnosis...... and treatment is important for the reversibility of the condition. In this case report we emphasize the importance of blood pressure control in a post-partum woman, who had a rather complicated pregnancy. The symptoms of PRES were not recognized immediately because of failure to use and acknowledge a blood...

  18. Posterior breast cancer: Mammographic and ultrasonographic features

    Directory of Open Access Journals (Sweden)

    Janković Ana

    2013-01-01

    Full Text Available Background/Aim. Posterior breast cancers are located in the prepectoral region of the breast. Owing to this distinctive anatomical localization, physical examination and mammographic or ultrasonographic evaluation can be difficult. The purpose of the study was to assess possibilities of diagnostic mammography and breast ultrasonography in detection and differentiation of posterior breast cancers. Methods. The study included 40 women with palpable, histopathological confirmed posterior breast cancer. Mammographic and ultrasonographic features were defined according to Breast Imaging Reporting and Data System (BI-RADS lexicon. Results. Based on standard two-view mammography 87.5%, of the cases were classified as BI-RADS 4 and 5 categories, while after additional mammographic views all the cases were defined as BIRADS 4 and 5 categories. Among 96 mammographic descriptors, the most frequent were: spiculated mass (24.0%, architectural distortion (16.7%, clustered microcalcifications (12.6% and focal asymmetric density (12.6%. The differentiation of the spiculated mass was significantly associated with the possibility to visualize the lesion at two-view mammography (p = 0.009, without the association with lesion diameter (p = 0.083 or histopathological type (p = 0.055. Mammographic signs of invasive lobular carcinoma were significantly different from other histopathological types (architectural distortion, p = 0.003; focal asymmetric density, p = 0.019; association of four or five subtle signs of malignancy, p = 0.006. All cancers were detectable by ultrasonography. Mass lesions were found in 82.0% of the cases. Among 153 ultrasonographic descriptors, the most frequent were: irregular mass (15.7%, lobulated mass (7.2%, abnormal color Doppler signals (20.3%, posterior acoustic attenuation (18.3%. Ultrasonographic BI-RADS 4 and 5 categories were defined in 72.5% of the cases, without a significant difference among various histopathological types (p = 0

  19. A Short History of Posterior Dynamic Stabilization

    Directory of Open Access Journals (Sweden)

    Cengiz Gomleksiz

    2012-01-01

    Full Text Available Interspinous spacers were developed to treat local deformities such as degenerative spondylolisthesis. To treat patients with chronic instability, posterior pedicle fixation and rod-based dynamic stabilization systems were developed as alternatives to fusion surgeries. Dynamic stabilization is the future of spinal surgery, and in the near future, we will be able to see the development of new devices and surgical techniques to stabilize the spine. It is important to follow the development of these technologies and to gain experience using them. In this paper, we review the literature and discuss the dynamic systems, both past and present, used in the market to treat lumbar degeneration.

  20. Superior labrum anterior-to-posterior tear.

    Science.gov (United States)

    Sum, Jonathan C; Omid, Reza

    2012-12-01

    The patient was a 25-year-old male college student with a chief complaint of right shoulder pain. The patient was initially diagnosed with bicipital tendinitis by his physician and had been treated for 4 weeks by a physical therapist. However, his symptoms did not improve and he was unable to return to his preinjury activity levels, so he sought the services of another physical therapist for a second opinion. Due to concern for a labrum tear, the physical therapist referred the patient to an orthopaedic surgeon. Magnetic resonance arthrography revealed findings consistent with a superior labrum anterior-to-posterior tear.

  1. Slope Deformation Prediction Based on Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Lei JIA

    2013-07-01

    Full Text Available This paper principally studies the prediction of slope deformation based on Support Vector Machine (SVM. In the prediction process,explore how to reconstruct the phase space. The geological body’s displacement data obtained from chaotic time series are used as SVM’s training samples. Slope displacement caused by multivariable coupling is predicted by means of single variable. Results show that this model is of high fitting accuracy and generalization, and provides reference for deformation prediction in slope engineering.

  2. Ultrasonographic Evaluation of Botulinum Toxin Injection Site for the Medial Approach to Tibialis Posterior Muscle in Chronic Stroke Patients with Spastic Equinovarus Foot: An Observational Study

    Directory of Open Access Journals (Sweden)

    Alessandro Picelli

    2017-11-01

    Full Text Available The tibialis posterior muscle is a frequent target for injection of botulinum toxin during the management of spastic equinovarus foot in adults with post-stroke spasticity. Although it is deep-seated, the needle insertion into the tibialis posterior muscle is usually performed using anatomical landmarks and safety information obtained from healthy subjects and cadavers. Our aim was to evaluate the botulinum toxin injection site for the medial approach to the tibialis posterior muscle in chronic stroke patients with spastic equinovarus foot. Forty-six patients were evaluated at the affected middle lower leg medial surface with ultrasonography according to the following parameters: tibialis posterior muscle depth, thickness, and echo intensity. As to the spastic tibialis posterior, we found a mean muscle depth of 26.5 mm and a mean muscle thickness of 10.1 mm. Furthermore we observed a median tibialis posterior muscle echo intensity of 3.00 on the Heckmatt scale. The tibialis posterior muscle thickness was found to be inversely associated with its depth (p < 0.001 and echo intensity (p = 0.006. Furthermore, tibialis posterior muscle depth was found to be directly associated with its echo intensity (p = 0.004. Our findings may usefully inform manual needle placement into the tibialis posterior for the botulinum toxin treatment of spastic equinovarus foot in chronic stroke patients.

  3. Thermomechanical forcing of deep rock slope deformation: 2. The Randa rock slope instability

    Science.gov (United States)

    Gischig, Valentin S.; Moore, Jeffrey R.; Evans, Keith F.; Amann, Florian; Loew, Simon

    2011-12-01

    Deformation monitoring between 2004 and 2011 at the rock slope instability above Randa (Switzerland) has revealed an intriguing seasonal trend. Relative dislocation rates across active fractures increase when near-surface rock temperatures drop in the fall and decrease after snowmelt as temperatures rise. This temporal pattern was observed with different monitoring systems at the ground surface and at depths up to 68 m, and represents the behavior of the entire instability. In this paper, the second of two companion pieces, we interpret this seasonal deformation trend as being controlled by thermomechanical (TM) effects driven by near-surface temperature cycles. While Part 1 of this work demonstrated in a conceptual manner how TM effects can drive deep rock slope deformation and progressive failure, we present here in Part 2 a case study where temperature-controlled deformation trends were observed in a natural setting. A 2D discrete-element numerical model is employed, which allows failure along discontinuities and successfully reproduces the observed kinematics of the Randa instability. By implementing simplified ground surface temperature forcing, model results were able to reproduce the observed deformation pattern, and TM-induced displacement rates and seasonal amplitudes in the model are of the same order of magnitude as measured values. Model results, however, exhibit spatial variation in displacement onset times while field measurements show more synchronous change. Additional heat transfer mechanisms, such as fracture ventilation, likely create deviations from the purely transient-conductive temperature field modeled. We suggest that TM effects are especially important at Randa due to the absence of significant groundwater within the unstable rock mass.

  4. Carbonate slope morphology revealing bank-to-slope sediment transfer in Little Bahama Bank, Bahamas

    Science.gov (United States)

    Mulder, Thierry; Gillet, Hervé; Hanquiez, Vincent; Ducassou, Emmanuelle; Fauquembergue, Kelly; Conesa, Gilles; Principaud, Mélanie; Le Goff, Johan; Ragusa, Jérémy; Bujan, Stephane; Bashah, Sara

    2017-04-01

    New high-quality multibeam data depict the area located between Little Bahama Bank (LBB, Bahamas) and Blake Plateau. The survey details the morphology of a giant 135-km-long canyon, the Great Abaco Canyon (GAC) and its main characteristics. The canyon main axis runs parallel to the margin. The pathway shows several knickpoints and plunge pools. The most important knickpoint is underlined by an abrupt change in slope of the canyon thalweg. The last one leads to the opening towards the Blake Basin. Its morphologic head forms a vast receptacle but does not represent the main source of material at present. The material supplied through the LBB canyon systems does not reach this area which only shows lineaments related to the pathway of the Antilles current and restricted failure scars. Most of the supply comes from the canyon flanks. In the north, tributary canyons drain the contourite deposits forming large flat plateaus above the drowned carbonate platform of the Blake Plateau. In addition, these contourite plateaus are subjected to translational slides moving towards the northern edge of the canyon forming a dissymmetric debris accumulation along the toe of the north canyon edge. Another source of sediment are two large tributaries connecting the GAC directly to the LBB upper slope. Sub bottom profiles suggest the presence of a turbiditic levee on the tributary canyon sides and inferred turbiditic activity. Little Abaco Canyon (LAC) shows morphologic similarities with GAC but at a smaller size. However, the canyon seems more active in terms of sediment transport. Canyons draining the eastern part of LBB show fresh sedimentary structures (sediment waves) suggesting active sedimentary processes. These structures are made of clean sand with shallow water organisms suggesting a direct supply from the carbonate platform edge. In term of size and morphology, the GAC compares to the largest canyons in siliciclastic environments. Its originality comes from the fact it is

  5. [Diagnosis and management of posterior urethra disruptions].

    Science.gov (United States)

    Bensalah, K; Manunta, A; Guillé, F; Patard, J J

    2006-10-01

    Rupture of posterior urethra is usually seen in major traumas with associated pelvic fractures. Clinical presentation classically associates blood at the uretral meatus and urinary retention. Urinary diversion should be achieved by suprapubic puncture and major associated traumatic injuries (abdominal, orthopaedic, and neurological lesions) must be treated prior to urological management. Retrograde uretrocystography is performed a few days later in order to localize and classify the urethral lesion. Treatment of posterior urethral ruptures has evolved over the years. Immediate open repair is no longer recommended. The supra-pubic catheter can be left in place until resorption of the pelvic hematoma. Obliteration occurs in 100% of the cases and is treated by open surgery at 3 months. More and more patients are treated by early endoscopic realignment which has diminished by half the incidence of urethral strictures. Impotence and incontinence secondary to trauma or surgery occur in 20% and 10% of the patients respectively. Long term follow-up should be achieved in every patient.

  6. Posterior Interosseous Nerve Syndrome from Thermal Injury

    Directory of Open Access Journals (Sweden)

    Vijay A. Singh

    2014-01-01

    Full Text Available Background. Due to anatomical proximity to bone, the radial nerve is the most frequently injured major nerve of the upper extremity, frequently secondary to fractures (Li et al. (2013. We describe an incidence when a branch of the radial nerve is injured as a result of a thermal injury. Observation. Radial nerve injury can occur anywhere along the anatomical course with varied etiologies, but commonly related to trauma. The most frequent site is in the proximal forearm involving the posterior interosseous branch. However, problems can occur at the junction of the middle and proximal thirds of the humerus and wrist radially. When the radial nerve is injured by a burn, a new rehabilitation dynamic arises. Not only does one agonize about the return of nerve function but also fret about the skin grafts that replaced the devitalized tissue housing that compartment. Discussion. Although posterior interosseous nerve syndrome has been described in the context of many different etiologies, it has not previously been discussed in relation to burn injuries. In this case, not only did the patient’s rehabilitation involve aggressive therapy for return of sensation and function of the arm, but also prevention of contracture normally seen in replacement of full thickness burns.

  7. Reconstruction of Acetabular Posterior Wall Fractures

    Science.gov (United States)

    Ahn, Jae-Min; Hur, Jun-Oh; Lee, Jong-Seo; Cheon, Sang-Jin

    2011-01-01

    Background The results after acetabular fracture are primarily related to the quality of the articular reduction. We evaluated the results of internal fixation of posterior wall fractures with using three-step reconstruction. Methods Thirty-three patients (mean age at the time of injury, 47.9 years; 28 males and 5 females) were followed for a minimum of 2 years after surgery. The three-step reconstruction included 1) preservation of soft tissues and reduction of the marginally impacted osteochondral (articular) fragments using screws, 2) filling the impacted cancellous void with a bone graft, and 3) reinforcement with buttress-plating. Clinical evaluation was done according to the criteria of D'aubigne and Postel, while the radiological criteria were those of Matta. The associated injuries and complications were evaluated. Results The clinical results were excellent in 15 (45.5%) patients and they were good in 5 (15.2%), (i.e., satisfactory in 60.7%), while the radiologic results were excellent in 10 (30.3%) and good in 14 (42.4%) (satisfactory in 72.7%). Heterotopic ossification was common, but this did not require excision, even without prophylactic treatment with indomethacin. Deep infection was the worst complication and this was accompanied by a poor outcome. Conclusions This study confirms that three-step reconstruction facilitates accurate and firm reduction of displaced posterior wall fractures of the acetabulum. Therefore, we anticipate less long-term arthrosis in the patients treated this way. PMID:21629471

  8. Treatment of posterior wall fractures of acetabulum.

    Science.gov (United States)

    Qi, Xin; Liu, Jian-Guo; Gong, Yu-Bao; Yang, Chen; Li, Shu-Qiang; Feng, Wei

    2009-04-01

    To explore the treatment methods and outcome of posterior wall fractures of the acetabulum. The data of 31 patients (25 males and 6 females, aged 19-59 years, mean: 40.5 years) with posterior wall fractures of the acetabulum hospitalized in our department from 2002 to 2006 were analyzed retrospectively in this study. The types of fractures, number of fragments, combined dislocations, and sciatic nerve function were documented before admission. All the fractures were treated with open reduction and internal fixation. Based on the fracture type and site, either screws alone or reconstructive plates were used. The patients were immobilized for an average of 12 weeks before partial weight bearing was permitted. After follow-up for 12-70 months (43.6 months on average), modified Merle d'Aubigne score was adopted to evaluate the outcomes of the operations. The percentages of the excellent, good, fair and poor results were 48.4%, 41.9%, 6.5%, and 3.3%, respectively, with a good to excellent rate of 90.2%. Idiopathic sciatic nerve injury occurred in only one case. The sciatic nerve should be routinely exposed and protected during the surgery. The type of fixation should be based on the fracture type and site. Prolonged immobilization may be helpful in improving the final outcomes.

  9. Hydatidosis of the liver and posterior mediastinum.

    Science.gov (United States)

    Quail, Jacob F; Gramins, Daniel L; Dutton, William D

    2015-01-01

    Cystic echinococcus (CE) is an endemic zoonosis secondary to infection by the larval form of the cestode Echinococcus granulosus. An intermediate host, humans enter the organism's life cycle by exposure to infected canid feces. The liver is the most common location of CE while mediastinal hydatid cysts are rarely reported. We report a case of synchronous CE of the liver and posterior mediastinum treated sequentially using chemotherapy, percutaneous aspiration with injection of a scolicidal agent and re-aspiration (PAIR) and then staged minimally-invasive surgeries. Synchronous CE involving the liver and posterior mediastinum is rare. The treatment of hydatid liver and mediastinal disease is multimodal including chemotherapy, percutaneous and laparoscopic or open surgical interventions. One option for controlled puncture of hepatic and mediastinal CE includes PAIR followed by surgery. The sequential use of chemotherapy and PAIR followed by surgery provides another treatment strategy for management of CE. We believe this strategy may be used safely in locations without endemic CE, including most regions of the United States. Published by Elsevier Ltd.

  10. Bayesian posterior distributions without Markov chains.

    Science.gov (United States)

    Cole, Stephen R; Chu, Haitao; Greenland, Sander; Hamra, Ghassan; Richardson, David B

    2012-03-01

    Bayesian posterior parameter distributions are often simulated using Markov chain Monte Carlo (MCMC) methods. However, MCMC methods are not always necessary and do not help the uninitiated understand Bayesian inference. As a bridge to understanding Bayesian inference, the authors illustrate a transparent rejection sampling method. In example 1, they illustrate rejection sampling using 36 cases and 198 controls from a case-control study (1976-1983) assessing the relation between residential exposure to magnetic fields and the development of childhood cancer. Results from rejection sampling (odds ratio (OR) = 1.69, 95% posterior interval (PI): 0.57, 5.00) were similar to MCMC results (OR = 1.69, 95% PI: 0.58, 4.95) and approximations from data-augmentation priors (OR = 1.74, 95% PI: 0.60, 5.06). In example 2, the authors apply rejection sampling to a cohort study of 315 human immunodeficiency virus seroconverters (1984-1998) to assess the relation between viral load after infection and 5-year incidence of acquired immunodeficiency syndrome, adjusting for (continuous) age at seroconversion and race. In this more complex example, rejection sampling required a notably longer run time than MCMC sampling but remained feasible and again yielded similar results. The transparency of the proposed approach comes at a price of being less broadly applicable than MCMC.

  11. Bayesian Posterior Distributions Without Markov Chains

    Science.gov (United States)

    Cole, Stephen R.; Chu, Haitao; Greenland, Sander; Hamra, Ghassan; Richardson, David B.

    2012-01-01

    Bayesian posterior parameter distributions are often simulated using Markov chain Monte Carlo (MCMC) methods. However, MCMC methods are not always necessary and do not help the uninitiated understand Bayesian inference. As a bridge to understanding Bayesian inference, the authors illustrate a transparent rejection sampling method. In example 1, they illustrate rejection sampling using 36 cases and 198 controls from a case-control study (1976–1983) assessing the relation between residential exposure to magnetic fields and the development of childhood cancer. Results from rejection sampling (odds ratio (OR) = 1.69, 95% posterior interval (PI): 0.57, 5.00) were similar to MCMC results (OR = 1.69, 95% PI: 0.58, 4.95) and approximations from data-augmentation priors (OR = 1.74, 95% PI: 0.60, 5.06). In example 2, the authors apply rejection sampling to a cohort study of 315 human immunodeficiency virus seroconverters (1984–1998) to assess the relation between viral load after infection and 5-year incidence of acquired immunodeficiency syndrome, adjusting for (continuous) age at seroconversion and race. In this more complex example, rejection sampling required a notably longer run time than MCMC sampling but remained feasible and again yielded similar results. The transparency of the proposed approach comes at a price of being less broadly applicable than MCMC. PMID:22306565

  12. Study of hemostasis procedures for posterior epistaxis.

    Science.gov (United States)

    Iimura, Jiro; Hatano, Atsushi; Ando, Yuji; Arai, Chiaki; Arai, Satoshi; Shigeta, Yasushi; Kojima, Hiromi; Otori, Nobuyoshi; Wada, Kota

    2016-06-01

    Hemostasis is difficult in patients with bleeding emanating from the deep regions in the nasal cavity; however, there is no standard treatment method. We studied hemostasis procedures in patients who visited our outpatient department and presented with idiopathic epistaxis extending from the posterior nasal cavity to Kiesselbach's area. The subjects were patients with epistaxis who visited our hospital between June 2008 and May 2010. We asked specific questions at the time of the hospital visit and examined patients using a nasal speculum, a flexible endoscope, and a rigid endoscope (0 or 70 degree) to identify bleeding sites. Hemostasis using electrocoagulation was selected as the first-line therapy for patients in whom a bleeding point had been identified, whereas hemostasis using a gauze tampon was performed in patients in whom the bleeding point was unknown. The subjects were analyzed by multivariate logistic regression analysis. The bleeding point was unknown in most cases of recurrent posterior epistaxis. Electrocoagulation was the best hemostasis procedure. Identifying the bleeding points as much as possible and performing electrocoagulation at these sites was the preferred procedures. We propose the treatment procedure for refractory epistaxis. When it is difficult to identify a bleeding point in a patient with refractory epistaxis due to a deviated nasal septum, a bleeding point should be identified after septoplasty; for bleeding from the sphenopalatine artery region, electrocoagulation or endoscopic cauterization of the sphenopalatine artery should be performed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Submarine slope failures due to pipe structure formation.

    Science.gov (United States)

    Elger, Judith; Berndt, Christian; Rüpke, Lars; Krastel, Sebastian; Gross, Felix; Geissler, Wolfram H

    2018-02-19

    There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.

  14. Percent Agricultural Land Cover on Steep Slopes (Future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Clearing land for agriculture tends to increase soil erosion. The amount of erosion is related to the steepness of the slope, farming methods used and soil type....

  15. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter....... The experimental results of measured loop-gain at different operating points are presented to validate the theoretical performance of the controller....

  16. Slope movements in Callejón de Huyalas, Peru

    Czech Academy of Sciences Publication Activity Database

    Vilímek, V.; Zapata, M. L.; Stemberk, Josef

    2003-01-01

    Roč. 35, supplementum (2003), s. 39-51 ISSN 0300-5402 Institutional research plan: CEZ:AV0Z3046908 Keywords : slope movements * natural hazards * Cordillera Blanca Subject RIV: DB - Geology ; Mineralogy

  17. Clay mineral distribution on the Kerala continental shelf and slope

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Nair, R.R.; Hashimi, N.H.

    minerals are quartz and feldspar. Kaolinite and gibbsite have low values on the outer shelf and high values on the inner shelf and slope, while illite increases in the offshore direction. However, montmorillonite behaves differently from others in having...

  18. Slope Stabilization Using Recycled Plastic Pins, Phase III.

    Science.gov (United States)

    2007-01-01

    A new technique for stabilizing surficial slope failures using recycled plastic reinforcing members has been developed. The : objective of the project described in this report has been to develop, evaluate, and document a technique for stabilization ...

  19. Probabilistic analysis algorithm for UA slope software program.

    Science.gov (United States)

    2013-12-01

    A reliability-based computational algorithm for using a single row and equally spaced drilled shafts to : stabilize an unstable slope has been developed in this research. The Monte-Carlo simulation (MCS) : technique was used in the previously develop...

  20. North Slope, Alaska ESI: T_MAMMAL (Terrestrial Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for brown bears, caribou, and muskoxen for the North Slope, Alaska. Vector polygons in this data set...

  1. North Slope, Alaska ESI: M_MAMMAL (Marine Mammal Polygons)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for whales, seals, walruses, and polar bears for the North Slope of Alaska. Vector polygons in this data...

  2. Landslide hazard on the slopes of Dabicho Ridge, Wondo Genet ...

    African Journals Online (AJOL)

    1996-06-18

    Landslide hazard on the slopes of Dabicho Ridge, Wondo Genet area: the case of June 18, 1996 event. Berhanu Temesgen, Mohammed Umer, Asfawossen Asrat, Ogbaghebriel Berakhi, Abayneh Ayele, Dramis Francesco, Metasebia Demissie ...

  3. Systems of pillarless working of adjacent, sloped and inclined seams

    Energy Technology Data Exchange (ETDEWEB)

    Batmanov, Yu.K.; Bakhtin, A.F.; Bulavka, E.I.

    1979-01-01

    An analysis is made (advantages and disadvantages) of existing and recommended (pillarless) systems of working adjacent, sloped, and inclined seams. The economic benefits, area and extent of those systems are indicated. 8 references, 4 figures.

  4. Effect of slope height and horizontal forces on the bearing capacity of strip footings near slopes in cohesionless soil

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Damkilde, Lars; Krabbenhøft, Kristian

    2016-01-01

    The problem of determining the bearing capacity of a strip foundation located near a slope of infinite height has been dealt with by several authors. Very often in practical problems the slope is of limited height, and furthermore the resulting load may be inclined at an angle to the horizontal......, and in such cases the bearing capacity of the footing cannot be found using the existing methods. The present work comprises finite element based upper- and lower-bound calculations, using the geotechnical software OptumG2 to investigate the effect of the slope height and horizontal forces on the total bearing...

  5. An acute posterior myocardial infarction complicated with late pseudoaneurysm of the posterior wall.

    Science.gov (United States)

    Dewilde, Willem; Muyldermans, Luc; Delanote, Joost; Bol, Alexander

    2006-08-10

    Diagnostic image: An 80-year-old man is referred because of an acute posterior infarction. Because of persisting pain and apparition of a new murmur, an echocardiography is performed showing inferoposterolateral akinesis complicated by ventricular wall pseudoaneurysm. After discussing with patient and family, conservative therapy was continued. A clue for diagnosis of pseudoaneurysm is the presence of a systolic murmur.

  6. Slope Impacts on Concentrated Flow Hydraulics in Rangeland

    Science.gov (United States)

    Al-Hamdan, O. Z.; Pierson, F. B.; Williams, C. J.; Kormos, P. R.; Nearing, M. A.; Boll, J.

    2009-12-01

    Several studies have been conducted to describe rill or concentrated flow hydraulics. However, most of these studies used data obtained from either laboratory experiments or field sites located on gently sloping crop lands. The data sets in the few rangeland field studies conducted did not cover a variety of hillslope angles and generally focused on slope gradients less than 20%. The lack of studies with steeper slopes resulted in misinterpreting the slope gradient impact on concentrated flow hydraulics, as sites with different slopes have different soil and vegetation cover characteristics. This study examines the characteristics of rangeland concentrated flow hydraulics as a function of vegetation and ground cover using field experimental data from diverse vegetated rangeland sites of the western United States. These data span a wide range of slope angles (5.6%-65.8%), soil types, and vegetative cover. Many of the sites exhibit some degree of disturbance, such as wild fire, prescribed fire, tree mastication, and/or tree cutting. The data were divided into two sets, gently sloping (20%). Analyses were performed on each data set separately as well as on the combined data set. For the complete data set, concentrated flow occurred on less than 26% of the gently sloping plots and on more than 70% of the steep plots. The results showed that the Darcy-Weisbach roughness coefficient (f) had no significant correlation with vegetation and ground cover variables on the gently sloping sites. However, roughness coefficient f was positively correlated with vegetation and ground cover on steep rangelands (R2=0.53, n=439). The power relation relating the flow width (w) to the discharge (Q) was statistically different on the gentle and the steep sites. A multi regression equation for estimating the width of the concentrated flow as a function of flow discharge, slope, and vegetation cover was developed (R2=0.62, n=360), where the variation of slope alone explained 39% of the

  7. Mass movement hazard assessment model in the slope profile

    Science.gov (United States)

    Colangelo, A. C.

    2003-04-01

    The central aim of this work is to assess the spatial behaviour of critical depths for slope stability and the behaviour of their correlated variables in the soil-regolith transition along slope profiles over granite, migmatite and mica-schist parent materials in an humid tropical environment. In this way, we had making measures of shear strength for residual soils and regolith materials with soil "Cohron Sheargraph" apparatus and evaluated the shear stress tension behaviour at soil-regolith boundary along slope profiles, in each referred lithology. In the limit equilibrium approach applied here we adapt the infinite slope model for slope analysis in whole slope profile by means of finite element solution like in Fellenius or Bishop methods. In our case, we assume that the potential rupture surface occurs at soil-regolith or soil-rock boundary in slope material. For each slice, the factor of safety was calculated considering the value of shear strength (cohesion and friction) of material, soil-regolith boundary depth, soil moisture level content, slope gradient, top of subsurface flow gradient, apparent soil bulk density. The correlations showed the relative weight of cohesion, internal friction angle, apparent bulk density of soil materials and slope gradient variables with respect to the evaluation of critical depth behaviour for different simulated soil moisture content levels at slope profile scale. Some important results refer to the central role of behaviour of soil bulk-density variable along slope profile during soil evolution and in present day, because the intense clay production, mainly Kaolinite and Gibbsite at B and C-horizons, in the humid tropical environment. A increase in soil clay content produce a fall of friction angle and bulk density of material, specially when some montmorillonite or illite clay are present. We have observed too at threshold conditions, that a slight change in soil bulk-density value may disturb drastically the equilibrium of

  8. Effect of cement injection on sandy soil slope stability, case study: slope in Petang district, Badung regency

    Science.gov (United States)

    Arya, I. W.; Wiraga, I. W.; GAG Suryanegara, I.

    2018-01-01

    Slope is a part of soil topography formed due to elevation difference from two soil surface. Landslides is frequently occur in natural slope, it is because shear force is greater than shear strength in the soil. There are some factor that influence slope stability such as: rain dissipation, vibration from earthquake, construction and crack in the soil. Slope instability can cause risk in human activity or even threaten human lives. Every years in rainy season, landslides always occur in Indonesia. In 2016, there was some landslide occurred in Bali. One of the most damaging is landslide in Petang district, Badung regency. This landslide caused main road closed entirely. In order to overcome and prevent landslide, a lot of method have been practiced and still looking for more sophisticated method for forecasting slope stability. One of the method to strengthen soil stability is filling the soil pores with some certain material. Cement is one of the material that can be used to fill the soil pores because when it is in liquid form, it can infiltrate into soil pores and fill the gap between soil particles. And after it dry, it can formed a bond with soil particle so that soil become stronger and the slope as well. In this study, it will use experimental method, slope model in laboratory to simulate a real slope behavior in the field. The first model is the slope without any addition of cement. This model will be become a benchmark for the other models. The second model is a slope with improved soil that injects the slope with cement. Injection of cement is done with varying interval distance of injection point is 5 cm and 10 cm. Each slope model will be given a load until the slope collapses. The slope model will also be analyzed with slope stability program. The test results on the improved slope models will be compared with unimproved slope. In the initial test will consist of 3 model. First model is soil without improvement or cement injection, second model is soil

  9. NRL Glider Data Report for the Shelf-Slope Experiment

    Science.gov (United States)

    2017-09-12

    Transformation and Transport in the Northern Gulf of Mexico: Platform Proof of Concept for the Ocean Observing System in the Northern Gulf of Mexico...glider SL083 was deployed for the Shelf-Slope experiment: “Shelf-Slope Interactions and Carbon Transformation and Transport in the Northern Gulf of... Digital Environmental Model (GDEM) climatology profiles. Optics QC generates flags to indicate that manual examination of profiles is required. Both

  10. Digital analysis of the slopes of Rab Island

    OpenAIRE

    Mladen Pahernik

    2007-01-01

    The paper analyzes morphometric features of the slopes of Rab Island. Based on the digital elevation model, raster layers were calculated for the values of slope angle, aspect and curvature, as well as valley network, which was grouped using the Strahler method. A comparative analysis of the calculated values of morphometric parameters was conducted in the GIS environment. Spatial distribution of the values of each of the morphometric parameters was correlated to the structural and morphogene...

  11. Modelling the influence of tree removal on embankment slope hydrology

    OpenAIRE

    Briggs, Kevin; Smethurst, Joel; Powrie, William

    2014-01-01

    Trees cover the slopes of many railway earthworks supporting the UK’s transport network. Root water uptake by trees can cause seasonal shrinkage and swelling of the embankment soil, affecting the line and level of the railway track. This requires continual maintenance to maintain the serviceability of the track and reduce train speed restrictions. However, the removal of trees from railway embankment slopes and the loss of soil suctions generated by root water uptake may negatively impact emb...

  12. Effects of surface slope on erosion rates of quartz particles

    OpenAIRE

    Lodge, Phillip.

    2006-01-01

    Modeling sediment erosion is important in a wide range of environmental problems. The effects of various environmental factors on erosion rates have been studied, but the effects of surface slope on erosion rates of a wide range of sediments have not been quantified. The effects of surface slope, both in the direction of flow (pitch) and perpendicular to the flow (roll), on erosion rates of quartz particles were investigated using the Sediment Erosion at Depth Flume (Sedflume). US Navy (US...

  13. Comparison of Glenoid Version and Posterior Humeral Subluxation in Patients With and Without Posterior Shoulder Instability.

    Science.gov (United States)

    Parada, Stephen A; Eichinger, Josef K; Dumont, Guillaume D; Burton, Lauren E; Coats-Thomas, Maggie S; Daniels, Stephen D; Sinz, Nathan J; Provencher, Matthew T; Higgins, Laurence D; Warner, Jon J P

    2017-02-01

    To evaluate glenoid version and humeral subluxation on preoperative multiplanar imaging of patients who underwent surgery for posterior glenohumeral instability compared with a matched group of patients who had shoulder surgery for other pathology. All patients over a 2-year period who underwent surgery for posterior instability had preoperative magnetic resonance (MR) imaging or MR arthrogram reviewed. Patients undergoing shoulder surgery for reasons other than instability were identified as a control group and matched by sex, laterality, and age. Measurement of glenoid version and percentage of humeral subluxation was performed by 2 reviewers after completing a tutorial. Reviewers were blinded to diagnosis and to whether or not the patients were in the experimental or control group. There were 41 patients in each group. The average glenoid version in the control group was 5.6° of retroversion (standard deviation [SD] 3.0), and the average humeral subluxation was 54% (SD 5.1%). In the experimental group, the average glenoid version was 8.1° of retroversion (SD 5.0). The average humeral subluxation in the experimental group was 56% (SD 6.8%). Student t test revealed a statistically significant difference in glenoid version (P = .009) but not humeral subluxation (P = .25). Intra- and inter-rater reliability was measured by the intraclass correlation coefficient and found to have an excellent Fleiss rating with regard to both measurements. Glenoid retroversion is significantly increased in patients with symptomatic posterior labral tears compared with a control group. However, there was no statistically significant difference between the groups with regard to posterior humeral subluxation and, therefore, is not a reliable indicator of the presence or absence of symptomatic posterior shoulder instability. Level III, retrospective comparative study. Published by Elsevier Inc.

  14. Spatial position influences perception of slope from graphs.

    Science.gov (United States)

    Parrott, Stacey; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Huntington, Mark D; Suzuki, Satoru

    2014-01-01

    We routinely examine linear trends from bar graphs and scatterplots while taking a science class, attending a business presentation, or reading a magazine article. Graphs are placed in different positions on a page or a presentation slide for aesthetic considerations. However, because left and right positions tend to be associated with lower and higher values in the conventional depiction of numerical values, we hypothesized that the perception of positive and negative slopes may be influenced by the placement of a graph. Using a visual search task, with each display containing four bar graphs or scatterplots (one per quadrant), we have demonstrated that the detection of a negative slope is selectively slowed in the upper-right quadrant (for both bar graphs and scatterplots), whereas the detection of a positive slope is selectively slowed in the upper-left quadrant (for bar graphs only). These results suggest that an upper-right position is incompatible with perceiving negative slopes and an upper-left position is incompatible with perceiving positive slopes. Although the origin of these specific associations is unclear, our results have implications for where to place a graph depending on the slope it displays.

  15. [Judet posterior approach to the scapula].

    Science.gov (United States)

    Bartonícek, J; Tucek, M; Lunácek, L

    2008-12-01

    A detailed description of the Judet posterior approach to the scapula. The authors used this approach in 24 patients operated on for fractures of the scapular body and neck and for combined fractures of the scapula. In 23 patients the surgical site healed without complications, in 1 case revision was required due to a haematoma. DESCRIPTION OF THE APPROACH: The approach has three phases. The first of them consists in a boomerang skin incision along the scapular spine and the medial scapular border producing a skin flap, and identification of the posterior border of the deltoid. In the next phase, the posterior deltoid is dissected off the scapular spine and reflected laterally. In the final phase, the infraspinatus is mobilized and reflected proximally. During the whole procedure the neurovascular bundle passing from the spinoglenoid notch to the infraspinatus must be handled with maximum caution. In certain types of fractures of the scapula, this approach may be limited using a medial and a lateral window to expose the respective borders of the scapular body, without full mobilization of the infraspinatus. On the other hand, where the fracture of the scapula is associated with a fracture of the lateral clavicle or dislocation of the AC joint, the approach may be extended using a saber cut incision starting from the proximolateral angle of the Judet incision and passing over the AC joint. This modification was used in a fracture of the scapular body associated with dislocation of the AC joint. The advantage of the Judet approach is an excellent exposure of the infraspinousus fossa. The main disadvantage of this approach is considered its extensiveness and atrophy of the infraspinatus that is most probably caused by its mobilization. However, there may be more causes of this atrophy. The first of them is injury to the suprascapular nerve in fractures of the surgical neck of the scapula by its entrapment in the fracture line. In these fractures the whole course of

  16. Dexmedetomidine sedation in painful posterior segment surgery

    Directory of Open Access Journals (Sweden)

    Mansour A

    2012-12-01

    Full Text Available Ahmad Mansour,1,2 Samar Taha31Department of Ophthalmology, American University of Beirut, Beirut, Lebanon; 2Rafik Hariri University Hospital, Beirut, Lebanon; 3Department of Anesthesiology, American University of Beirut, Beirut, LebanonPurpose: To present a case series on the use of dexmedetomidine (Precedex sedation in painful posterior segment surgery performed under topical anesthesia, similar to its use in cataract surgery.Methods: A prospective review of cases that had posterior segment surgery under topical anesthesia and that needed sedation. Dexmedetomidine-loading infusion was 1 mcg/kg over 10 minutes, followed by a maintenance infusion (0.5 mcg/kg/h.Results: Nine patients were operated on under topical anesthesia: two scleral buckle, five cryopexy, one scleral laceration, and one pars plana vitrectomy with very dense laser therapy in an albinotic fundus; six patients had retinal detachment. General or local anesthesia were not possible due to medical or ocular morbidities, use of anticoagulants, or the surgery plan changed intraoperatively when new pathologies were discovered. The surgeon achieved good surgical control in eight of nine cases, with one patient having ocular and bodily movements that were disturbing. Six patients had no pain, while three patients reported mild pain. No adverse effects were noted and all patients had successful surgical outcomes. Heart rate, blood pressure, and oxygen saturation were well controlled throughout the procedures. The most frequent adverse reactions of dexmedetomidine reported in the literature in less than 5% (hypotension, bradycardia, and dry mouth were not recorded in the present study.Conclusion: When a surgeon has planned to do a pars plana vitrectomy under topical anesthesia and the surgical situation dictates the addition of cryopexy, scleral buckle, or intense laser retinopexy, then sedation with dexmedetomidine can help in the control of ocular pain in the majority of cases, with good

  17. Assessment of shallow subsurface characterisation with non-invasive geophysical methods at the intermediate hill-slope scale

    Directory of Open Access Journals (Sweden)

    S. Popp

    2013-04-01

    Full Text Available Hill-slopes of several hectares in size represent a difficult scale for subsurface characterisation, as these landscape units are well beyond the scope of traditional point-scale techniques. By means of electromagnetic induction (EMI and gamma-ray spectroscopy, spatially distributed soil proxy data were collected from a heterogeneous hill-slope site. Results of EMI mapping using the EM38DD showed that soil electrical conductivity (ECa is highly variable at both temporal and spatial scales. Calibration of the integral ECa signal to a specific target like soil moisture is hampered by the ambiguous response of EMI to the clay-rich hill-slope underground. Gamma-ray results were obtained during a single survey, along with EMI measurements and selected soil sampling. In contrast to ECa, a noticeable correlation between Total Count and K emission data and soil-water content seemed to be present. Relevant proxy variables from both methods were used for k means clustering in order to distinguish between hill-slope areas with different soil conditions. As a result, we obtained a suitable partition of hill-slope that was comparable with a previously obtained zonation model based on ecological factors.

  18. Retention versus sacrifice of the posterior cruciate ligament in total knee arthroplasty for treating osteoarthritis.

    Science.gov (United States)

    Verra, Wiebe C; van den Boom, Lennard G H; Jacobs, Wilco; Clement, Darren J; Wymenga, Ate A B; Nelissen, Rob G H H

    2013-10-11

    group. Results from the outcome Knee Society functional score were homogeneous. All other outcome measures (extension angle, knee pain, adverse effects, clinical questionnaire scores, Knee Society clinical scores, radiological rollback, radiolucencies, femorotibial angle and tibial slope) showed no statistically significant differences between the groups. In the subgroup analyses that allowed pooling of the results of the different studies, no homogeneous statistically significant differences were identified. The methodological quality and the quality of reporting of the studies were highly variable. With respect to range of motion, pain, clinical, and radiological outcomes, no clinically relevant differences were found between total knee arthroplasty with retention or sacrifice of the posterior cruciate ligament. Two statistically significant differences were found; range of motion was 2.4 ° higher in the posterior cruciate ligament sacrificing group, however results were heterogeneous; and the mean functional Knee Society Score was 2.3 points higher in the posterior cruciate ligament sacrificing group. These differences are clinically not relevant.

  19. Soil properties in high-elevation ski slopes

    Science.gov (United States)

    Filippa, Gianluca; Freppaz, Michele; Letey, Stéphanie; Corti, Giuseppe; Cocco, Stefania; Zanini, Ermanno

    2010-05-01

    The development of winter sports determines an increasing impact on the high altitude ecosystems, as a consequence of increased participation and an increasing demand of high quality standards for skiable areas. The construction of a ski slope is associated with a certain impact on soil, which varies as a function of the degree of human-induced disturbance to the native substrata. In this work, we provide a description of the characteristics of alpine tundra ski-slope soils and their nutrient status, contrasted with undisturbed areas. The study site is located in the Monterosaski Resort, Aosta Valley, NW Italy (45°51' N; 7°48' E). We chose 5 sites along an altitudinal gradient between 2700 and 2200 m a.s.l.. Per each site, one plot was established on the ski slope, while a control plot was chosen under comparable topographic conditions a few meters apart. Soils were described and samples were collected and analysed for main chemical-physical properties. In addition an evaluation of N forms, organic matter fractionation and microbial biomass was carried out. Soil depth ranged between 10 to more than 70 cm, both on the ski slope and in the undisturbed areas. A true organo-mineral (A) horizon was firstly identified at 2500 m a.s.l., while a weathering horizon (Bw) was detected at 2400 m a.s.l.. However, a Bw horizon thick enough to be recognised as diagnostic for shifting soil classification order from Entisols to Inceptisols (USDA-Soil Taxonomy) was detected only below 2400 m a.s.l.. Lithic Cryorthents were predominant in the upper part of the sequence (above 2500 m a.s.l.), both in the ski slope and the undisturbed areas; Typic Cryorthents were identified between 2500 and 2400 m a.s.l., while Inceptisols were predominant between 2400 and 2200 m a.s.l.. Chemical-physical properties will be discussed focusing on the main differences between ski slope and undisturbed soils, as determined by the ski slope construction. Pedogenetic processes at high altitude are

  20. Slope Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Slope was calculated from the bathymetry surface for each raster cell using ArcGIS's Spatial Analyst 'Slope' Tool. Slope describes the maximum steepness of a terrain...

  1. Elastic K-means using posterior probability.

    Science.gov (United States)

    Zheng, Aihua; Jiang, Bo; Li, Yan; Zhang, Xuehan; Ding, Chris

    2017-01-01

    The widely used K-means clustering is a hard clustering algorithm. Here we propose a Elastic K-means clustering model (EKM) using posterior probability with soft capability where each data point can belong to multiple clusters fractionally and show the benefit of proposed Elastic K-means. Furthermore, in many applications, besides vector attributes information, pairwise relations (graph information) are also available. Thus we integrate EKM with Normalized Cut graph clustering into a single clustering formulation. Finally, we provide several useful matrix inequalities which are useful for matrix formulations of learning models. Based on these results, we prove the correctness and the convergence of EKM algorithms. Experimental results on six benchmark datasets demonstrate the effectiveness of proposed EKM and its integrated model.

  2. Iodine-125 radiation of posterior uveal melanoma

    International Nuclear Information System (INIS)

    Packer, S.

    1987-01-01

    Twenty-eight cases of posterior choroidal melanoma were treated with iodine-125 in gold eye plaques. Eleven cases were located within 3.0 mm of the optic nerve (group A), nine were within 3.0 mm of the fovea (group B), and eight were within 3.0 mm of the optic nerve and fovea (group C). The mean follow-up of group A was 46.3 months; group B, 25.5 months; and group C, 42.7 months. Complications included macular edema, cataract and tumor growth. Visual acuity remained within two lines of that tested preoperatively for 4 of 11 patients in group A, 4 of 9 in group B, and 5 of 8 in group C. These results with iodine-125 suggest it as an appropriate treatment for patients with choroidal melanoma located near optic nerve and/or macula

  3. Iodine-125 radiation of posterior uveal melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Packer, S.

    1987-12-01

    Twenty-eight cases of posterior choroidal melanoma were treated with iodine-125 in gold eye plaques. Eleven cases were located within 3.0 mm of the optic nerve (group A), nine were within 3.0 mm of the fovea (group B), and eight were within 3.0 mm of the optic nerve and fovea (group C). The mean follow-up of group A was 46.3 months; group B, 25.5 months; and group C, 42.7 months. Complications included macular edema, cataract and tumor growth. Visual acuity remained within two lines of that tested preoperatively for 4 of 11 patients in group A, 4 of 9 in group B, and 5 of 8 in group C. These results with iodine-125 suggest it as an appropriate treatment for patients with choroidal melanoma located near optic nerve and/or macula.

  4. Imaging of the posterior pelvic floor

    Energy Technology Data Exchange (ETDEWEB)

    Stoker, Jaap [Department of Radiology, Academic Medical Center, University of Amsterdam (Netherlands); Bartram, Clive I.; Halligan, Steve [Intestinal Imaging Centre, St. Mark' s Hospital, London (United Kingdom)

    2002-04-01

    Disorders of the posterior pelvic floor are relatively common. The role of imaging in this field is increasing, especially in constipation, prolapse and anal incontinence, and currently imaging is an integral part of the investigation of these pelvic floor disorders. Evacuation proctography provides both structural and functional information for rectal voiding and prolapse. Dynamic MRI may be a valuable alternative as the pelvic floor muscles are visualised, and it is currently under evaluation. Endoluminal imaging is important in the management of anal incontinence. Both endosonography and endoanal MRI can be used for detection of anal sphincter defects. Endoanal MRI has the advantage of simultaneously evaluating external sphincter atrophy, which is an important predictive factor for the outcome of sphincter repair. Many aspects of constipation and prolapse remain incompletely understood and treatment is partly empirical; however, imaging has a central role in management to place patients into treatment-defined groups. (orig.)

  5. Imaging of the posterior pelvic floor

    International Nuclear Information System (INIS)

    Stoker, Jaap; Bartram, Clive I.; Halligan, Steve

    2002-01-01

    Disorders of the posterior pelvic floor are relatively common. The role of imaging in this field is increasing, especially in constipation, prolapse and anal incontinence, and currently imaging is an integral part of the investigation of these pelvic floor disorders. Evacuation proctography provides both structural and functional information for rectal voiding and prolapse. Dynamic MRI may be a valuable alternative as the pelvic floor muscles are visualised, and it is currently under evaluation. Endoluminal imaging is important in the management of anal incontinence. Both endosonography and endoanal MRI can be used for detection of anal sphincter defects. Endoanal MRI has the advantage of simultaneously evaluating external sphincter atrophy, which is an important predictive factor for the outcome of sphincter repair. Many aspects of constipation and prolapse remain incompletely understood and treatment is partly empirical; however, imaging has a central role in management to place patients into treatment-defined groups. (orig.)

  6. MR imaging of posterior cruciate ligament injuries

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Nobuyuki [Tsukuba Univ., Ibaraki (Japan). Hospital; Niitsu, Mamoru; Itai, Yuji; Sato, Motohiro; Kujiraoka, Yuka; Ikeda, Kotaro; Kanamori, Akihiro

    2001-07-01

    Posterior cruciate ligament (PCL) injuries are less frequent than anterior cruciate ligament (ACL) injuries, but are presumably more common than once thought. Thirty-nine patients with PCL injuries identified on MR images were studied. The criteria for PCL injury were complete tear, partial tear, and avulsion fracture. The approximate site of a partial tear was categorized as proximal, midsubstance, distal, or combination. Fourteen patients (35.9%) had complete tears of the PCL, 21 patients (53.8%) had partial tears, and four patients (10.3%) had avulsion fractures. A total of 12 patients (30.7%) had isolated PCL injuries, while the remaining 27 patients demonstrated evidence of other coexistent knee injuries, such as meniscal tears and ligamentous injuries. Of coexistent knee injuries, meniscal tears (18 patients, 46.2%) were most often seen. (author)

  7. Minimally invasive surgical approach to treat posterior urethral diverticulum

    Directory of Open Access Journals (Sweden)

    Ossamah Alsowayan

    2015-01-01

    Full Text Available Urethral diverticulum is a localized saccular or fusiform out-pouching of the urethra. It may occur at any point along the urethra in both male and females. Male urethral diverticulum is rare, and could be either congenital or acquired, anterior or posterior. The mainstay treatment of posterior urethral diverticulum (PUD is the open surgical approach. Here we discuss our minimally invasive surgical approach (MIS in managing posterior urethral diverticulum.

  8. Vitamin D deficiency and posterior subcapsular cataract

    Directory of Open Access Journals (Sweden)

    Brown CJ

    2015-06-01

    Full Text Available Craig J Brown,1 Faical Akaichi21The Eye Center, Fayetteville, AR, USA; 2Scotland’s Rural College, Edinburgh, UKPurpose: To evaluate risk factors associated with posterior subcapsular cataract (PSC development and the relationship between vitamin D deficiency and etiology of PSC.Methods: Of 195 consecutive patients from a private ophthalmology practice, diagnosed with PSC, serum vitamin D3 (25-OH D levels were obtained for 175, and associations among risk factors, comorbidities, and PSC were assessed.Results: In all 175 PSC patients, mean 25-OH D levels were low (24 ng/mL ±11 SD compared with age/sex-matched standards. Significant differences in 25-OH D levels were noted between PSC subjects taking/not taking calcium supplements, systemic steroids, osteoporosis medications, etc. Alone, smoking status and calcium channel blockers and/or topical steroids use made no significant difference in PSC subjects 25-OH D levels, but two or more of these factors were associated with lowered levels of 25-OH D (P<0.001. Low vitamin D was correlated with female sex, autoimmune disease, and non-skin cancer diagnosis, but not with age, or other comorbidities or medication use. In five early-stage PSC patients taking 5,000 IU of 25-OH D daily for vitamin D deficiency, there was resolution of their cataracts during the 2-year follow-up period.Conclusion: Vitamin D levels for most PSC patients fell below the 30 ng/mL calcium homeostasis threshold. Some comorbidities and non-ophthalmic interventions are associated with the development of PSC at less depressed levels of 25-OH D. In this series, vitamin D deficiency was associated with PSC cataract, suggesting that raising the level of vitamin D intake may reduce PSC incidence.Keywords: posterior subcapsular, cataracts, vitamin D deficiency, risk factors, hypocalcemia, case report

  9. Posterior longitudinal ligament status in cervical spine bilateral facet dislocations

    Energy Technology Data Exchange (ETDEWEB)

    Carrino, John A. [Brigham and Women' s Hospital, Harvard Medical School, Department of Radiology, Boston, MA (United States); Manton, Geoffrey L.; Morrison, William B.; Flanders, Adam E. [Thomas Jefferson University Hospital, Department of Radiology, Philadelphia, PA (United States); Vaccaro, Alex R. [Thomas Jefferson University Hospital, Department of Orthopedic Surgery, The Rothman Institute, Philadelphia, PA (United States); Schweitzer, Mark E. [New York University, Hospital for Joint Diseases, Department of Radiology, New York, NY (United States)

    2006-07-15

    It is generally accepted that cervical spine bilateral facet dislocation results in complete disruption of the posterior longitudinal ligament. The goal of this study was to evaluate the integrity of numerous spine-stabilizing structures by MRI, and to determine if any associations between injury patterns exist with respect to the posterior longitudinal ligament status. Retrospective case series. A retrospective review was performed of 30 cervical spine injury subjects with bilateral facet dislocation. Assessment of 1.5T MRI images was carried out for: intervertebral disc disruption, facet fracture, and ligamentous disruption. Statistical analyses were performed to evaluate for associations between various injury patterns and posterior longitudinal ligament status. The frequency of MRI abnormalities was: anterior longitudinal ligament disruption (26.7%), disc herniation or disruption (90%), posterior longitudinal ligament disruption (40%), facet fracture (63.3%) and disruption of the posterior column ligament complex (97%). There were no significant associations between injury to the posterior longitudinal ligament and other structures. Compared to surgical reports, MRI was accurate for determining the status for 24 of 26 ligaments (three of three anterior longitudinal ligament, seven of nine posterior longitudinal ligament, and 14 of 14 posterior column ligament complex) but generated false negatives in two instances (in both MRI showed an intact posterior longitudinal ligament that was torn at surgery). (orig.)

  10. Effects of slope smoothing in river channel modeling

    Science.gov (United States)

    Kim, Kyungmin; Liu, Frank; Hodges, Ben R.

    2017-04-01

    In extending dynamic river modeling with the 1D Saint-Venant equations from a single reach to a large watershed there are critical questions as to how much bathymetric knowledge is necessary and how it should be represented parsimoniously. The ideal model will include the detail necessary to provide realism, but not include extraneous detail that should not exert a control on a 1D (cross-section averaged) solution. In a Saint-Venant model, the overall complexity of the river channel morphometry is typically abstracted into metrics for the channel slope, cross-sectional area, hydraulic radius, and roughness. In stream segments where cross-section surveys are closely spaced, it is not uncommon to have sharp changes in slope or even negative values (where a positive slope is the downstream direction). However, solving river flow with the Saint-Venant equations requires a degree of smoothness in the equation parameters or the equation set with the directly measured channel slopes may not be Lipschitz continuous. The results of non-smoothness are typically extended computational time to converge solutions (or complete failure to converge) and/or numerical instabilities under transient conditions. We have investigated using cubic splines to smooth the bottom slope and ensure always positive reference slopes within a 1D model. This method has been implemented in the Simulation Program for River Networks (SPRNT) and is compared to the standard HEC-RAS river solver. It is shown that the reformulation of the reference slope is both in keeping with the underlying derivation of the Saint-Venant equations and provides practical numerical stability without altering the realism of the simulation. This research was supported in part by the National Science Foundation under grant number CCF-1331610.

  11. Ultrasound elasticity imaging of human posterior tibial tendon

    Science.gov (United States)

    Gao, Liang

    Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with irreversible degradation of its collagen structure, leading to changes to its mechanical properties. If these properties could be monitored in vivo, it could be used to quantify the severity of tendonosis and help determine the appropriate treatment. Ultrasound elasticity imaging (UEI) is a real-time, noninvasive technique to objectively measure mechanical properties in soft tissue. It consists of acquiring a sequence of ultrasound frames and applying speckle tracking to estimate displacement and strain at each pixel. The goals of my dissertation were to 1) use acoustic simulations to investigate the performance of UEI during tendon deformation with different geometries; 2) develop and validate UEI as a potentially noninvasive technique for quantifying tendon mechanical properties in human cadaver experiments; 3) design a platform for UEI to measure mechanical properties of the PTT in vivo and determine whether there are detectable and quantifiable differences between healthy and diseased tendons. First, ultrasound simulations of tendon deformation were performed using an acoustic modeling program. The effects of different tendon geometries (cylinder and curved cylinder) on the performance of UEI were investigated. Modeling results indicated that UEI accurately estimated the strain in the cylinder geometry, but underestimated in the curved cylinder. The simulation also predicted that the out-of-the-plane motion of the PTT would cause a non-uniform strain pattern within incompressible homogeneous isotropic material. However, to average within a small region of interest determined by principal component analysis (PCA

  12. Direct Strain and Slope and Slope Measurement Using 2D DSPSI

    International Nuclear Information System (INIS)

    Dandach, W.; Molimard, J.; Picart, P.

    2011-01-01

    Large variety of optical full-field measurement techniques are being developed and applied to solve mechanical problems. Since each technique possesses its own merits, it is important to know the capabilities and limitations of such techniques. Among these optical full-field methods, interferometry techniques take an important place. They are based on illumination with coherent light (laser). In shearing interferometry the difference of the out of-plane displacement in two neighboring object points is directly measured. Since object displacement does not result in interferometry fringes, the method is suited for localization of strain concentrations and is indeed used in industry for this purpose. DSPSI possesses the advantage over conventional out-of-plane displacement-sensitive interferometry, that only a single difference of the unwrapped phase map is required to obtain flexural strains, thereby relieving problems with noise and reduction in the field of view. A first work in this domain (DSPSI) [1] was made in 1973, later recent studies emerged to provide a quantitative system of measurements [2]. This work aims to present the results of strain and slope measurements using digital speckle pattern shearing interferometry (DSPSI). (author)

  13. A isometricidade do ligamento cruzado posterior Isometry of the posterior cruciate ligament

    Directory of Open Access Journals (Sweden)

    Alexandre E. V. Kokron

    2001-06-01

    Full Text Available Trabalho de revisão bibliográfica referente à isometricidade do ligamento cruzado posterior. São avaliados doze artigos que estudam a isometricidade do ligamento, constatando que a maioria destes é concorde com a maior importância da inserção femoral na isometricidade e que existe uma linha ou área mais isométrica na inserção femoral, aproximadamente perpendicular ao teto da fossa intercondilar, localizada de 10 a 14mm da abertura anterior desta fossa.The authors review 12 studies about posterior cruciate ligament isometry. The authors conclude that most studies agree that femoral insertion of the ligament is more important for isometry, and that there is a most isometric line or area inside the femoral insertion, perpendicular to the roof of the intercondilar fossa, approximately 10 to 14mm from its anterior opening.

  14. Slope Error Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stynes, J. K.; Ihas, B.

    2012-04-01

    The National Renewable Energy Laboratory (NREL) has developed an optical measurement tool for parabolic solar collectors that measures the combined errors due to absorber misalignment and reflector slope error. The combined absorber alignment and reflector slope errors are measured using a digital camera to photograph the reflected image of the absorber in the collector. Previous work using the image of the reflection of the absorber finds the reflector slope errors from the reflection of the absorber and an independent measurement of the absorber location. The accuracy of the reflector slope error measurement is thus dependent on the accuracy of the absorber location measurement. By measuring the combined reflector-absorber errors, the uncertainty in the absorber location measurement is eliminated. The related performance merit, the intercept factor, depends on the combined effects of the absorber alignment and reflector slope errors. Measuring the combined effect provides a simpler measurement and a more accurate input to the intercept factor estimate. The minimal equipment and setup required for this measurement technique make it ideal for field measurements.

  15. Physical Analysis Work for Slope Stability at Shah Alam, Selangor

    Science.gov (United States)

    Ishak, M. F.; Zaini, M. S. I.

    2018-04-01

    Slope stability analysis is performed to assess the equilibrium conditions and the safe design of a human-made or natural slope to find the endangered areas. Investigation of potential failure and determination of the slope sensitivity with regard to safety, reliability and economics were parts of this study. Ground anchor is designed to support a structure in this study. Ground anchor were implemented at the Mechanically Stabilized Earth (MSE) wall along Anak Persiaran Jubli Perak to overcome the further cracking of pavement parking, concrete deck and building of the Apartments. A result from the laboratory testing of soil sample such as index test and shear strength test were applied to the Slope/W software with regard to the ground anchors that were implemented. The ground anchors were implemented to increase the value of the factor of safety (FOS) of the MSE Wall. The value of the factor of safety (FOS) before implementing the ground anchor was 0.800 and after the ground anchor was implemented the value increase to 1.555. The increase percentage of factor of safety by implementing on stability of slope was 94.38%.

  16. Landform Degradation and Slope Processes on Io: The Galileo View

    Science.gov (United States)

    Moore, Jeffrey M.; Sullivan, Robert J.; Chuang, Frank C.; Head, James W., III; McEwen, Alfred S.; Milazzo, Moses P.; Nixon, Brian E.; Pappalardo, Robert T.; Schenk, Paul M.; Turtle, Elizabeth P.; hide

    2001-01-01

    The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on Io. We recognize four major slope types observed on a number of intermediate resolution (250 m/pixel) images and several additional textures on very high resolution (10 m/pixel) images. Slopes and scarps on Io often show evidence of erosion, seen in the simplest form as alcove-carving slumps and slides at all scales. Many of the mass movement deposits on Io are probably mostly the consequence of block release and brittle slope failure. Sputtering plays no significant role. Sapping as envisioned by McCauley et al. remains viable. We speculate that alcove-lined canyons seen in one observation and lobed deposits seen along the bases of scarps in several locations may reflect the plastic deformation and 'glacial' flow of interstitial volatiles (e.g., SO2) heated by locally high geothermal energy to mobilize the volatile. The appearance of some slopes and near-slope surface textures seen in very high resolution images is consistent with erosion from sublimation-degradation. However, a suitable volatile (e.g., H2S) that can sublimate fast enough to alter Io's youthful surface has not been identified. Disaggregation from chemical decomposition of solid S2O and other polysulfur oxides may conceivably operate on Io. This mechanism could degrade landforms in a manner that resembles degradation from sublimation, and at a rate that can compete with resurfacing.

  17. Surface drainage in leveled land: Implication of slope

    Directory of Open Access Journals (Sweden)

    Antoniony S. Winkler

    Full Text Available ABSTRACT In the lowlands of Rio Grande do Sul, land leveling is mostly carried out with no slope for the purpose of rice production. In this environment, soils with a low hydraulic conductivity are predominant owing to the presence of a practically impermeable B-horizon near the surface. Land leveling leads to soil accommodation resulting in the formation of depressions where water accumulates after heavy rainfalls, subsequently leading to problems with crops implanted in succession to rice, such as soybeans. The objective of this research was to quantify the areas and volumes of water accumulation in soil as a function of the slope of land leveling. Five typical leveled lowland areas were studied as a part of this research. The original areas presented slopes of 0, 0.20, 0.25, 0.28 and 0.40%, which were used to generate new digital elevation models with slopes between 0 and 0.5%. These newly generated digital models were used to map the depressions with surface water storage. In conclusion, land leveling with slopes higher than 0.1% is recommended to minimize problems with superficial water storage in rice fields.

  18. Characterization of Unstable Rock Slopes Through Passive Seismic Measurements

    Science.gov (United States)

    Kleinbrod, U.; Burjanek, J.; Fäh, D.

    2014-12-01

    Catastrophic rock slope failures have high social impact, causing significant damage to infrastructure and many casualties throughout the world each year. Both detection and characterization of rock instabilities are therefore of key importance. An analysis of ambient vibrations of unstable rock slopes might be a new alternative to the already existing methods, e.g. geotechnical displacement measurements. Systematic measurements have been performed recently in Switzerland to study the seismic response of potential rockslides concerning a broad class of slope failure mechanisms and material conditions. Small aperture seismic arrays were deployed at sites of interest for a short period of time (several hours) in order to record ambient vibrations. Each measurement setup included a reference station, which was installed on a stable part close to the instability. Recorded ground motion is highly directional in the unstable parts of the rock slope, and significantly amplified with respect to stable areas. These effects are strongest at certain frequencies, which were identified as eigenfrequencies of the unstable rock mass. In most cases the directions of maximum amplification are perpendicular to open cracks and in good agreement with the deformation directions obtained by geodetic measurements. Such unique signatures might improve our understanding of slope structure and stability. Thus we link observed vibration characteristics with available results of detailed geological characterization. This is supported by numerical modeling of seismic wave propagation in fractured media with complex topography.For example, a potential relation between eigenfrequencies and unstable rock mass volume is investigated.

  19. Control and perception of balance at elevated and sloped surfaces.

    Science.gov (United States)

    Simeonov, Peter I; Hsiao, Hongwei; Dotson, Brian W; Ammons, Douglas E

    2003-01-01

    Understanding roof-work-related risk of falls and developing low-cost, practical engineering controls for reducing this risk remain in high demand in the construction industry. This study investigated the effects of the roof work environment characteristics of surface slope, height, and visual reference on standing balance in construction workers. The 24 participants were tested in a laboratory setting at 4 slopes (0 degrees, 18 degrees, 26 degrees, and 34 degrees), 2 heights (0, 3 m), and 2 visual conditions (with and without visual references). Postural sway characteristics were calculated using center of pressure recordings from a force platform. Workers' perceptions of postural sway and instability were also evaluated. The results indicated that slope and height synergistically increased workers' standing postural instability. Workers recognized the individual destabilizing effects of slope and height but did not recognize the synergistic effect of the two. Visual references significantly reduced the destabilizing effects of height and slope. Actual and potential applications of this research include the use of temporary level work surfaces and proximal vertical reference structures as postural instability control measures during roofing work.

  20. The Influence of Slope Breaks on Lava Flow Surface Disruption

    Science.gov (United States)

    Glaze, Lori S.; Baloga, Stephen M.; Fagents, Sarah A.; Wright, Robert

    2014-01-01

    Changes in the underlying slope of a lava flow impart a significant fraction of rotational energy beyond the slope break. The eddies, circulation and vortices caused by this rotational energy can disrupt the flow surface, having a significant impact on heat loss and thus the distance the flow can travel. A basic mechanics model is used to compute the rotational energy caused by a slope change. The gain in rotational energy is deposited into an eddy of radius R whose energy is dissipated as it travels downstream. A model of eddy friction with the ambient lava is used to compute the time-rate of energy dissipation. The key parameter of the dissipation rate is shown to be rho R(sup 2/)mu, where ? is the lava density and mu is the viscosity, which can vary by orders of magnitude for different flows. The potential spatial disruption of the lava flow surface is investigated by introducing steady-state models for the main flow beyond the steepening slope break. One model applies to slow-moving flows with both gravity and pressure as the driving forces. The other model applies to fast-moving, low-viscosity, turbulent flows. These models provide the flow velocity that establishes the downstream transport distance of disrupting eddies before they dissipate. The potential influence of slope breaks is discussed in connection with field studies of lava flows from the 1801 Hualalai and 1823 Keaiwa Kilauea, Hawaii, and 2004 Etna eruptions.

  1. Hyperstereopsis in helmet-mounted NVDs: slope perception

    Science.gov (United States)

    Stuart, Geoffrey W.; Flanagan, Patrick; Gibbs, Peter

    2007-04-01

    Modern helmet-mounted night vision devices, such as the Thales TopOwl helmet, project imagery from intensifiers mounted on the sides of the helmet onto the helmet faceplate. This produces a situation of hyperstereopsis in which binocular disparities are magnified. This has the potential to distort the perception of slope in depth (an important cue to landing), because the slope cue provided by binocular disparity conflicts with veridical cues to slope, such as texture gradients and motion parallax. In the experiments, eight observers viewed sparse and dense textured surfaces tilted in depth under three viewing conditions: normal stereo hyper-stereo (4 times magnification), and hypostereo (1/4 magnification). The surfaces were either stationary, or rotated slowly around a central vertical axis. Stimuli were projected at 6 metres to minimise conflict between accommodation and convergence, and stereo viewing was provided by a Z-screen and passive polarised glasses. Observers matched perceived visual slope using a small tilt table set by hand. We found that slope estimates were distorted by hyperstereopsis, but to a much lesser degree than predicted by disparity magnification. The distortion was almost completely eliminated when motion parallax was present.

  2. 25G posterior capsulotomy with anterior vitrectomy for posterior capsule opacification

    Directory of Open Access Journals (Sweden)

    Ying-Jie Lin

    2014-03-01

    Full Text Available AIM: To evaluate the efficacy and complications of 25G posterior capsulotomy with anterior vitrectomy for posterior capsule opacification(PCO. METHODS: The 25G transconjunctival sutureless vitrectomy technique was performed in 48 cases(68 eyesof PCO eyes. The mean follow-up was 24mo. Best-corrected visual acuity(BCVA, intraocular pressure, anterior chamber reaction and complications during and after the operation were observed. RESULTS: 4mm diameter round holes were obtained at the center of the posterior capsule in all eyes. At 1d postoperative, uncorrected visual acuity(UCVAwas 0.70±0.12(0.5-1.0, and BCVA was 0.73±0.10(0.6-1.0. At 3mo postoperative, UCVA was 0.72±0.12(0.5-1.0, and BCVA was 0.74±0.10(0.6-1.0. It was statistical significance between preoperative and postoperative UCVA(t=-45.902, P=0.000. There were no complications during the postoperative follow-up period, such as dislocation or damage of the IOL, corneal edema, endoophthalmitis, pupil vitreous hernia, vitreous prolapse, retina detachment, intraocular hypertension and reocclusion of the visual axis, etc.CONCLUSION: The 25G transconjunctival sutureless vitrectomy technique to remove PCO is a safe and effective procedure with less complications, which can be an alternative treatment for PCO.

  3. Minimal-invasive posterior approach in the treatment of the posterior wall fractures of the acetabulum.

    Science.gov (United States)

    Spagnolo, Rosario; Bonalumi, Matteo; Pace, Fabrizio; Capitani, Dario

    2009-05-01

    We examined patients affected by a posterior wall fracture of the acetabulum treated with a minimally invasive posterior approach (from 12 to 18 cm). During 2004-2006 19 patients were treated by this approach. 4 patients had a combined surgery by the ileo-inguinal approach. Fracture fixation was performed using reconstruction plates and screws. All the patients were studied with typical X-rays projection for pelvis and iliac oblique view and obturator oblique view (Judet view) and CT scan with 3D reconstruction. After 3 months a CT scan was performed on about 30% of our patients, which demonstrated the perfect healing of the fractures. The most important advantages we observed using this approach were a lesser split of the gluteus maximus and no risk of damage for the superior gluteal nerve. In the early post-operative rehabilitation we examined the trophism of the gluteus maximus, which was found to be better than in patients treated with the typical Kocher-Langenbeck approach. The only absolute contraindication for this technique is in obese patients. The post-operative complications include one case of heterotypic ossification of the gluteus minimus and one case of peroneal-nerve palsy with the spontaneous and complete recovery within 6 months. According to our experience this kind of approach could be used for posterior wall fracture of the pelvis and it can be extended to transverse fractures. In the post-operative period the greatest advantage is the lesser muscle damage and therefore a most effective rehabilitation.

  4. Target Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — [Part of the ATLAS user facility.] The Physics Division operates a target development laboratory that produces targets and foils of various thickness and substrates,...

  5. Probabilistic approaches for geotechnical site characterization and slope stability analysis

    CERN Document Server

    Cao, Zijun; Li, Dianqing

    2017-01-01

    This is the first book to revisit geotechnical site characterization from a probabilistic point of view and provide rational tools to probabilistically characterize geotechnical properties and underground stratigraphy using limited information obtained from a specific site. This book not only provides new probabilistic approaches for geotechnical site characterization and slope stability analysis, but also tackles the difficulties in practical implementation of these approaches. In addition, this book also develops efficient Monte Carlo simulation approaches for slope stability analysis and implements these approaches in a commonly available spreadsheet environment. These approaches and the software package are readily available to geotechnical practitioners and alleviate them from reliability computational algorithms. The readers will find useful information for a non-specialist to determine project-specific statistics of geotechnical properties and to perform probabilistic analysis of slope stability.

  6. Rock mass characterisation and stability analyses of excavated slopes

    Science.gov (United States)

    Zangerl, Christian; Lechner, Heidrun

    2016-04-01

    Excavated slopes in fractured rock masses are frequently designed for open pit mining, quarries, buildings, highways, railway lines, and canals. These slopes can reach heights of several hundreds of metres and in cases concerning open pit mines slopes larger than 1000 m are not uncommon. Given that deep-seated slope failures can cause large damage or even loss of life, the slope design needs to incorporate sufficient stability. Thus, slope design methods based on comprehensive approaches need to be applied. Excavation changes slope angle, groundwater flow, and blasting increases the degree of rock mass fracturing as well as rock mass disturbance. As such, excavation leads to considerable stress changes in the slopes. Generally, slope design rely on the concept of factor of safety (FOS), often a requirement by international or national standards. A limitation of the factor of safety is that time dependent failure processes, stress-strain relationships, and the impact of rock mass strain and displacement are not considered. Usually, there is a difficulty to estimate the strength of the rock mass, which in turn is controlled by an interaction of intact rock and discontinuity strength. In addition, knowledge about in-situ stresses for the failure criterion is essential. Thus, the estimation of the state of stress of the slope and the strength parameters of the rock mass is still challenging. Given that, large-scale in-situ testing is difficult and costly, back-calculations of case studies in similar rock types or rock mass classification systems are usually the methods of choice. Concerning back-calculations, often a detailed and standardised documentation is missing, and a direct applicability to new projects is not always given. Concerning rock mass classification systems, it is difficult to consider rock mass anisotropy and thus the empirical estimation of the strength properties possesses high uncertainty. In the framework of this study an approach based on

  7. Some Limits Using Random Slope Models to Measure Academic Growth

    Directory of Open Access Journals (Sweden)

    Daniel B. Wright

    2017-11-01

    Full Text Available Academic growth is often estimated using a random slope multilevel model with several years of data. However, if there are few time points, the estimates can be unreliable. While using random slope multilevel models can lower the variance of the estimates, these procedures can produce more highly erroneous estimates—zero and negative correlations with the true underlying growth—than using ordinary least squares estimates calculated for each student or school individually. An example is provided where schools with increasing graduation rates are estimated to have negative growth and vice versa. The estimation is worse when the underlying data are skewed. It is recommended that there are at least six time points for estimating growth if using a random slope model. A combination of methods can be used to avoid some of the aberrant results if it is not possible to have six or more time points.

  8. Mars Climate History: Insights From Impact Crater Wall Slope Statistics

    Science.gov (United States)

    Kreslavsky, Mikhail A.; Head, James W.

    2018-02-01

    We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.

  9. Development of a new generation of optical slope measuring profiler

    Energy Technology Data Exchange (ETDEWEB)

    Yashchuk, Valeriy V.; Takacs, Peter Z.; McKinney, Wayne R.; Assoufid, Lahsen; Siewert, Frank; Zeschke, Thomas

    2010-09-16

    A collaboration, including all DOE synchrotron labs, industrial vendors of x-ray optics, and with active participation of the HBZ-BESSY-II optics group has been established to work together on a new slope measuring profiler -- the optical slope measuring system (OSMS). The slope measurement accuracy of the instrument is expected to be<50 nrad for the current and future metrology of x-ray optics for the next generation of light sources. The goals were to solidify a design that meets the needs of mirror specifications and also be affordable; and to create a common specification for fabrication of a multi-functional translation/scanning (MFTS) system for the OSMS. This was accomplished by two collaborative meetings at the ALS (March 26, 2010) and at the APS (May 6, 2010).

  10. The Socioeconomic Assessment of Sloping Land Conversion Program in China

    DEFF Research Database (Denmark)

    Liu, Zhen

    with the aim to combat deforestation, ecological degradation, over cultivation of sloping land and soil erosion. However, we also believe it brings changes to the rural economic structure and household livelihood strategy. Applying and developing some empirical and theoretical methods with a large amount......Abstract This thesis mainly focuses on the socioeconomic impact of the largest Ecological Recovery Program ― the Sloping Land Conversion Program (SLCP), also called Grain for Green Program (GFG) in China. The central government initiated this program in 1999 and it was launched nationwide in 2002...... that there exist heterogeneous effects of SLCP implementation on livelihood diversification across different rural income groups. The lower income group was more affected by the program in terms of income diversification. The Second paper ― The Effects of Sloping Land Conversion Program on Agricultural Households...

  11. Automating slope monitoring in mines with terrestrial lidar scanners

    Science.gov (United States)

    Conforti, Dario

    2014-05-01

    Static terrestrial laser scanners (TLS) have been an important component of slope monitoring for some time, and many solutions for monitoring the progress of a slide have been devised over the years. However, all of these solutions have required users to operate the lidar equipment in the field, creating a high cost in time and resources, especially if the surveys must be performed very frequently. This paper presents a new solution for monitoring slides, developed using a TLS and an automated data acquisition, processing and analysis system. In this solution, a TLS is permanently mounted within sight of the target surface and connected to a control computer. The control software on the computer automatically triggers surveys according to a user-defined schedule, parses data into point clouds, and compares data against a baseline. The software can base the comparison against either the original survey of the site or the most recent survey, depending on whether the operator needs to measure the total or recent movement of the slide. If the displacement exceeds a user-defined safety threshold, the control computer transmits alerts via SMS text messaging and/or email, including graphs and tables describing the nature and size of the displacement. The solution can also be configured to trigger the external visual/audio alarm systems. If the survey areas contain high-traffic areas such as roads, the operator can mark them for exclusion in the comparison to prevent false alarms. To improve usability and safety, the control computer can connect to a local intranet and allow remote access through the software's web portal. This enables operators to perform most tasks with the TLS from their office, including reviewing displacement reports, downloading survey data, and adjusting the scan schedule. This solution has proved invaluable in automatically detecting and alerting users to potential danger within the monitored areas while lowering the cost and work required for

  12. Development of a GIS-based failure investigation system for highway soil slopes

    Science.gov (United States)

    Ramanathan, Raghav; Aydilek, Ahmet H.; Tanyu, Burak F.

    2015-06-01

    A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil slope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation ( P>200 mm). 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20° and 30°. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation (Leshchinsky et al., 2015).

  13. Determination of slope failure using 2-D resistivity method

    Science.gov (United States)

    Muztaza, Nordiana Mohd; Saad, Rosli; Ismail, Nur Azwin; Bery, Andy Anderson

    2017-07-01

    Landslides and slope failure may give negative economic effects including the cost to repair structures, loss of property value and medical costs in the event of injury. To avoid landslide, slope failure and disturbance of the ecosystem, good and detailed planning must be done when developing hilly area. Slope failure classification and various factors contributing to the instability using 2-D resistivity survey conducted in Selangor, Malaysia are described. The study on landslide and slope failure was conducted at Site A and Site B, Selangor using 2-D resistivity method. The implications of the anticipated ground conditions as well as the field observation of the actual conditions are discussed. Nine 2-D resistivity survey lines were conducted in Site A and six 2-D resistivity survey lines with 5 m minimum electrode spacing using Pole-dipole array were performed in Site B. The data were processed using Res2Dinv and Surfer10 software to evaluate the subsurface characteristics. 2-D resistivity results from both locations show that the study areas consist of two main zones. The first zone is alluvium or highly weathered with the resistivity of 100-1000 Ωm at 20-70 m depth. This zone consists of saturated area (1-100 Ωm) and boulders with resistivity value of 1200-3000 Ωm. The second zone with resistivity values of > 3000 Ωm was interpreted as granitic bedrock. The study area was characterized by saturated zones, highly weathered zone, highly contain of sand and boulders that will trigger slope failure in the survey area. Based on the results obtained from the study findings, it can be concluded that 2-D resistivity method is useful method in determination of slope failure.

  14. Evidence of slope instability in the Southwestern Adriatic Margin

    Directory of Open Access Journals (Sweden)

    D. Minisini

    2006-01-01

    Full Text Available The Southwestern Adriatic Margin (SAM shows evidence of widespread failure events that generated slide scars up to 10 km wide and extensive slide deposits with run out distances greater than 50 km. Chirp-sonar profiles, side-scan sonar mosaics, multibeam bathymetry and sediment cores document that the entire slope area underwent repeated failures along a stretch of 150 km and that mass-transport deposits, covering an area of 3320 km2, are highly variable ranging from blocky slides to turbidites, and lay on the lower slope and in the basin. The SAM slope between 300–700 m is impacted by southward bottom currents shaping sediment drifts (partly affected by failure and areas of dominant erosion of the seafloor. When slide deposits occur in areas swept by bottom currents their fresh appearence and their location at seafloor may give the misleading impression of a very young age. Seismic-stratigraphic correlation of these deposits to the basin floor, however, allow a more reliable age estimate through sediment coring of the post-slide unit. Multiple buried failed masses overlap each other in the lower slope and below the basin floor; the most widespread of these mass-transport deposits occurred during the MIS 2-glacial interval on a combined area of 2670 km2. Displacements affecting Holocene deposits suggest recent failure events during or after the last phases of the last post-glacial eustatic rise. Differences in sediment accumulation rates at the base or within the sediment drifts and presence of downlap surfaces along the slope and further in the basin may provide one or multiple potential weak layers above which widespread collapses take place. Neotectonic activity and seismicity, together with the presence of a steep slope, represent additional elements conducive to sediment instability and failure along the SAM. Evidence of large areas still prone to failure provides elements of tsunamogenic hazard.

  15. Posterior routes of choroidal blood outflow in high myopia.

    Science.gov (United States)

    Ohno-Matsui, K; Morishima, N; Ito, M; Yamashita, S; Tokoro, T

    1996-01-01

    A few reports in the ophthalmic literature have described choroidal blood outflow through posterior routes. Most of the patients reported were highly myopic; therefore, a correlation between such posterior routes and high myopia has been suspected. The authors examined highly myopic eyes using indocyanine green (ICG) videoangiography and investigated the prevalence and clinical significance of posterior routes in them. The authors examined 255 highly myopic eyes (146 patients) using ICG videoangiography. All had refractive errors greater than--8.25 diopters (D). They also examined a control group consisting of 42 eyes (26 patients) that had refractive errors within +/- 3D. Of 255 highly myopic eyes, 61 (23.9%) had choroidal blood outflow through posterior routes. These routes were classified by type of vein according to its penetration site. One drained into the margin of the optic nerve head, and the other penetrated the sclera near the macula. However, only 1 of the 42 eyes (2.4%) in the control group showed choroidal outflow by a posterior route. The prevalence of posterior routes was significantly higher in the highly myopic eyes than in the control group (P < 0.05). Posterior routes of choroidal blood outflow were observed in nearly 25% of highly myopic eyes. These vessels appear to be one of the major routes of posterior choroidal outflow in highly myopic eyes.

  16. Defect in Posterior Arch of Atlas in Myelomeningocele

    NARCIS (Netherlands)

    G. Blaauw (Gerhard)

    1971-01-01

    textabstractThe posterior arches of the cervical vertebrae of 30 children who died with a myelomeningocele in the lower thoracic, lumbar or sacral region were examined; in 70 per cent of these cases a defect was found in the posterior arch of the atlas, which was bridged by a firm fibrous band.

  17. Fetal MRI for characterising a variety of posterior fossa anomalies ...

    African Journals Online (AJOL)

    Fetal MRI is increasingly being used to more accurately assess abnormalities detected on screening ultrasound. The procedure is more pertinent when the initial ultrasound is done late in the third trimester and when the abnormality involves the posterior fossa of the brain. Four cases with a variety of unusual posterior fossa ...

  18. Posterior Debridement with Trans-Pedicular Screw Fixation For ...

    African Journals Online (AJOL)

    ... abscess formation, intractable pain or failure of medical management. The use of instrumentation is still controversial. Objective: Was to evaluate the surgical outcome of idiopathic lumbar spondylodiscitis treated with posterior debridement combined with single-stage posterior instrumentation and autologus bone grafting.

  19. Iatrogenic injury of an aberrant right posterior sectoral bile duct

    African Journals Online (AJOL)

    (Figs 1 and 2). A week later, an endoscopic retrograde cholangiopancreatography. (ERCP) examination was performed. This showed no filling of the right posterior sectoral ducts but normal opacification of the other ducts. (Figs 3a and b). These findings led to the diagnosis of an aberrant right posterior sectoral bile duct that ...

  20. Difficult management of posterior urethra gunshot wound combined ...

    African Journals Online (AJOL)

    Posterior urethra gunshot wounds are poorly described in the literature. They are often associated with pelvic vital lesions making difficult early repair of urethral injuries. They can be complicated by urethrorectal fistula, which makes their management more complicated. We report a new case of posterior urethra disruption ...

  1. Delayed primary realignment of posterior urethral rupture | Shittu ...

    African Journals Online (AJOL)

    The treatment of acute posterior urethral rupture is controversial. Twelve patients who presented with acute posterior urethral rupture over a five--year period were treated by delayed primary realignment of the injury. The technique of this procedure and the outcome are the subject of this presentation. Eight patients had ...

  2. Evaluation of the mechanical and physical properties of a posterior ...

    African Journals Online (AJOL)

    To evaluate the mechanical and physical properties of a micro-hybrid resin composite used in adult posterior restorations A micro-hybrid, light curing resin composite Unolux BCS Composite Restorative, (UnoDent, England) was used to restore 74 carious classes I and II cavities on posterior teeth of 62 adult patients.

  3. Posterior perforation of gastric ulcer: a rare surgical emergency ...

    African Journals Online (AJOL)

    BACKGROUND:Gastric ulcer perforation is a rare surgical emergency.Posterior gastric ulcer is even rarer and usually has a delayed presentation with attendant greater morbidity and mortality. AIM:To report a case of posterior perforation of gastric ulcer and review the literature. CASE REPORT:A 65yr old driver was seen in ...

  4. Posterior mediastinal mass: Do we need to worry much?

    Directory of Open Access Journals (Sweden)

    Parin Lalwani

    2013-01-01

    Full Text Available Anesthetic management of mediastinal masses is challenging. There is abundant literature available on anesthesia management of anterior mediastinal mass. Anesthetic management of posterior mediastinal mass lesions normally have uneventful course. We describe airway collapse and difficult mechanical ventilation in the postoperative period in a patient with posterior mediastinal mass.

  5. Early results of two methods of posterior spinal stabilization in ...

    African Journals Online (AJOL)

    2013-04-17

    Apr 17, 2013 ... Discussion. PSR has become the gold standard in posterior spinal fusion techniques. Its success has revolutionized spinal surgery. The Advantages include three column fusion as against one column fusion as is seen in other posterior fusion techniques like Rogers and Bohlman's techniques.[9‑13] Other.

  6. Posterior reversible encephalopathy syndrome in a adult female

    African Journals Online (AJOL)

    Oyinloye, et al.: Posterior reversible encephalopathy syndrome. Annals of African Medicine. Vol. 13, July-September, 2014. Page | 139. Classic neuroimaging applied to patients shows edema involving the white matter in the posterior portions of the cerebral hemispheres, especially bilaterally in the parieto‑occipital regions.

  7. A case of posterior shoulder dislocation with ipsilateral humeral ...

    African Journals Online (AJOL)

    A case of posterior shoulder dislocation with ipsilateral humeral shaft fracture. P Sharma, S Meena, D Rastogi, B Chowdhury. Abstract. Posterior shoulder dislocations are rare and represent 2–5% of all traumatic shoulder dislocation. A combination of this injury with ipsilateral humeral shaft fracture is extremely rare event.

  8. Material properties of the human posterior knee capsule

    NARCIS (Netherlands)

    Rachmat, H. H.; Janssen, D.; Verkerke, G. J.; Diercks, R. L.; Verdonschot, N.

    2015-01-01

    BACKGROUND: There is considerable interest to develop accurate subject-specific biomechanical models of the knee. Most of the existing models currently do not include a representation of the posterior knee capsule. In order to incorporate the posterior capsule in knee models, data is needed on its

  9. Material properties of the human posterior knee capsule

    NARCIS (Netherlands)

    Rachmat, H.H.; Janssen, D.W.; van Tienen, T.; Diercks, R.L.; Verkerke, Gijsbertus Jacob; Verdonschot, Nicolaas Jacobus Joseph; Fernandes, Paulo; Folgado, Joao; Silva, Miguel

    2012-01-01

    BACKGROUND: There is considerable interest to develop accurate subject-specific biomechanical models of the knee. Most of the existing models currently do not include a representation of the posterior knee capsule. In order to incorporate the posterior capsule in knee models, data is needed on its

  10. Topography of The Posterior Communicating Artery in a Kenyan ...

    African Journals Online (AJOL)

    *Note: B= Basillar artery ICA= Internal Carotid Artery. PCA= Posterior Cerebral artery. CN III= 3rd cranial nerve. A - Hypoplastic configuration. C- Transitional configuration. B- Co-existence of Adult [(PComA (A)] and fetal [PComA (F)] configuration. Topography of The Posterior Communicating Artery in a Kenyan Population.

  11. Management of Posterior Urethral Valves at Kilimanjaro Christian ...

    African Journals Online (AJOL)

    All the children clinically suspected to have posterior urethra valves had the diagnosis confirmed by micturating cystourethrogram and depending on their age, underwent initial vesicostomy and finally posterior urethral valve fulguration as the definitive treatment. Data regarding age at presentation, types of valves seen, ...

  12. Traumatic posterior dislocation of the hip: distribution and severity of ...

    African Journals Online (AJOL)

    These injuries take precedence in the emergency care of patients with posterior dislocation of the hip. The role of public enlightment on road safety measures cannot be over-emphasized and a case is made for training of the populace in essential basic life support. Keywords: Posterior hip dislocation; associated injuries; ...

  13. Comparison of Medial and Posterior Surgical Approaches in ...

    African Journals Online (AJOL)

    2017-10-26

    Oct 26, 2017 ... children, both surgical approaches revealed similar functional and radiological outcomes ... posterior approach. Two different surgical approaches (medial and posterior) were used by two surgeons with at least 5 years of trauma surgery ..... approach in management of type III supracondylar fractures of the.

  14. MRI evaluation of the posterior meniscus root tear

    International Nuclear Information System (INIS)

    Zhang Jianjun; Zheng Zhuozhao; Li Xuan

    2010-01-01

    Objective: To determine the value of MRI for diagnosing the posterior meniscus root tear. Methods: MR examinations of 30 patients with tear of the posterior meniscus root confirmed by knee arthroscopies were retrospectively reviewed. Of the 30 patients, 17 with posterior medial meniscus root tear (MMRT) and 13 with posterior lateral meniscus root tear (LMRT). The diagnostic sensitivity of' MRI for the posterior meniscus root tear was analyzed. Fisher's exact test was used to compare the detection rate of MRI for MMRT with that for LMRT. Results: All 17 cases with MMRT and 9 cases out of 13 with LMRT were correctly diagnosed by MRI and the diagnostic sensitivity of MRI for the posterior meniscus root tear was 86.7% (26/30). The main MR appearance of the posterior meniscus root tear was distortion of the meniscal root, with its low signal replaced by abnormal high signal. The detection rate of MRI for MMRT (17/17) was significantly greater than that for LMRT (9/13) (P=0.026). The prevalence of MMRT associated with meniscus extrusion (15/17) was significantly greater than that of LMRT (6/13) (P=0.020), but the prevalence of MMRT associated with anterior cruciate ligament (ACL) injury (5/17) was significantly lower than that of LMRT (11/13) (P=0.004). Conclusion: MRI is a relatively good method for detection of posterior meniscus root tears and associated injuries. (authors)

  15. Left posterior BA37 is involved in object recognition: a TMS study

    DEFF Research Database (Denmark)

    Stewart, Lauren; Meyer, Bernd-Ulrich; Frith, Uta

    2001-01-01

    Functional imaging studies have proposed a role for left BA37 in phonological retrieval, semantic processing, face processing and object recognition. The present study targeted the posterior aspect of BA37 to see whether a deficit, specific to one of the above types of processing could be induced...... to name pictures when TMS was given over lBA37 compared to vertex or rBA37. rTMS over lBA37 had no significant effect on word reading, nonword reading or colour naming. The picture naming deficit is suggested to result from a disruption to object recognition processes. This study corroborates the finding...... from a recent imaging study, that the most posterior part of left hemispheric BA37 has a necessary role in object recognition....

  16. Measurement of the π0 electromagnetic transition form factor slope

    Science.gov (United States)

    Lazzeroni, C.; Lurkin, N.; Romano, A.; Blazek, T.; Koval, M.; Ceccucci, A.; Danielsson, H.; Falaleev, V.; Gatignon, L.; Goy Lopez, S.; Hallgren, B.; Maier, A.; Peters, A.; Piccini, M.; Riedler, P.; Frabetti, P. L.; Gersabeck, E.; Kekelidze, V.; Madigozhin, D.; Misheva, M.; Molokanova, N.; Movchan, S.; Potrebenikov, Yu.; Shkarovskiy, S.; Zinchenko, A.; Rubin, P.; Baldini, W.; Cotta Ramusino, A.; Dalpiaz, P.; Fiorini, M.; Gianoli, A.; Norton, A.; Petrucci, F.; Savrié, M.; Wahl, H.; Bizzeti, A.; Bucci, F.; Iacopini, E.; Lenti, M.; Veltri, M.; Antonelli, A.; Moulson, M.; Raggi, M.; Spadaro, T.; Eppard, K.; Hita-Hochgesand, M.; Kleinknecht, K.; Renk, B.; Wanke, R.; Winhart, A.; Winston, R.; Bolotov, V.; Duk, V.; Gushchin, E.; Ambrosino, F.; Di Filippo, D.; Massarotti, P.; Napolitano, M.; Palladino, V.; Saracino, G.; Anzivino, G.; Imbergamo, E.; Piandani, R.; Sergi, A.; Cenci, P.; Pepe, M.; Costantini, F.; Doble, N.; Giudici, S.; Pierazzini, G.; Sozzi, M.; Venditti, S.; Balev, S.; Collazuol, G.; DiLella, L.; Gallorini, S.; Goudzovski, E.; Lamanna, G.; Mannelli, I.; Ruggiero, G.; Cerri, C.; Fantechi, R.; Kholodenko, S.; Kurshetsov, V.; Obraztsov, V.; Semenov, V.; Yushchenko, O.; D'Agostini, G.; Leonardi, E.; Serra, M.; Valente, P.; Fucci, A.; Salamon, A.; Bloch-Devaux, B.; Peyaud, B.; Engelfried, J.; Coward, D.; Kozhuharov, V.; Litov, L.; Arcidiacono, R.; Bifani, S.; Biino, C.; Dellacasa, G.; Marchetto, F.; Numao, T.; Retière, F.; NA62 Collaboration

    2017-05-01

    The NA62 experiment collected a large sample of charged kaon decays in 2007 with a highly efficient trigger for decays into electrons. A measurement of the π0 electromagnetic transition form factor slope parameter from 1.11 ×106 fully reconstructed K± →π± πD0, πD0 →e+e- γ events is reported. The measured value a = (3.68 ± 0.57) ×10-2 is in good agreement with theoretical expectations and previous measurements, and represents the most precise experimental determination of the slope in the time-like momentum transfer region.

  17. Wave Run-Up on Sloping Coastal Structures

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Ronde, J. De

    2001-01-01

    Wave run-up is one of the main physical processes which are taken into account in the design of the crest level of sloping coastal structures. The crest level design of these structures is mainly based on physical scale model results.......Wave run-up is one of the main physical processes which are taken into account in the design of the crest level of sloping coastal structures. The crest level design of these structures is mainly based on physical scale model results....

  18. After the Slippery Slope: Dutch Experiences on Regulating Active Euthanasia

    OpenAIRE

    Boer, Th.A.

    2003-01-01

    “When a country legalizes active euthanasia, it puts itself on a slippery slope from where it may well go further downward.” If true, this is a forceful argument in the battle of those who try to prevent euthanasia from becoming legal. The force of any slippery-slope argument, however, is by definition limited by its reference to future developments which cannot empirically be sustained. Experience in the Netherlands—where a law regulating active euthanasia was accepted in April 2001—may shed...

  19. Newton slopes for Artin-Schreier-Witt towers

    DEFF Research Database (Denmark)

    Davis, Christopher; Wan, Daqing; Xiao, Liang

    2016-01-01

    We fix a monic polynomial f(x)∈Fq[x] over a finite field and consider the Artin-Schreier-Witt tower defined by f(x); this is a tower of curves ⋯→Cm→Cm−1→⋯→C0=A1, with total Galois group Zp. We study the Newton slopes of zeta functions of this tower of curves. This reduces to the study of the Newton...... a result on the behavior of the slopes of the eigencurve associated to the Artin-Schreier-Witt tower, analogous to the result of Buzzard and Kilford....

  20. Posterior distributions for likelihood ratios in forensic science.

    Science.gov (United States)

    van den Hout, Ardo; Alberink, Ivo

    2016-09-01

    Evaluation of evidence in forensic science is discussed using posterior distributions for likelihood ratios. Instead of eliminating the uncertainty by integrating (Bayes factor) or by conditioning on parameter values, uncertainty in the likelihood ratio is retained by parameter uncertainty derived from posterior distributions. A posterior distribution for a likelihood ratio can be summarised by the median and credible intervals. Using the posterior mean of the distribution is not recommended. An analysis of forensic data for body height estimation is undertaken. The posterior likelihood approach has been criticised both theoretically and with respect to applicability. This paper addresses the latter and illustrates an interesting application area. Copyright © 2016 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

  1. Posterior endoscopic discectomy: Results in 300 patients

    Directory of Open Access Journals (Sweden)

    Mohinder Kaushal

    2012-01-01

    Full Text Available Background: Posterior endoscopic discectomy is an established method for treatment of lumbar disc herniation. Many studies have not been reported in literature for lumbar discectomy by Destandau Endospine System. We report a series of 300 patients operated for lumbar dissectomy by Destandau Endospine system. Materials and Methods: A total of 300 patients suffering from lumbar disc herniations were operated between January 2002 and December 2008. All patients were operated as day care procedure. Technique comprised localization of symptomatic level followed by insertion of an endospine system devise through a 15 mm skin and fascial incision. Endoscopic discectomy is then carried out by conventional micro disc surgery instruments by minimal invasive route. The results were evaluated by Macnab′s criteria after a minimum followup of 12 months and maximum up to 24 months. Results: Based on modified Macnab′s criteria, 90% patients had excellent to good, 8% had fair, and 2% had poor results. The complications observed were discitis and dural tear in five patients each and nerve root injury in two patients. 90% patients were able to return to light and sedentary work with an average delay of 3 weeks and normal physical activities after 2 months. Conclusion: Edoscopic discectomy provides a safe and minimal access corridor for lumbar discectomy. The technique also allows early postoperative mobilization and faster return to work.

  2. Representation of Numerosity in Posterior Parietal Cortex

    Directory of Open Access Journals (Sweden)

    Jamie D Roitman

    2012-05-01

    Full Text Available Humans and animals appear to share a similar representation of number as an analog magnitude on an internal, subjective scale. Neurological and neurophysiological data suggest that posterior parietal cortex (PPC is a critical component of the circuits that form the basis of numerical abilities in humans. Patients with parietal lesions are impaired in their ability to access the deep meaning of numbers. Acalculiac patients with inferior parietal damage often have difficulty performing arithmetic (2+4? or number bisection (what is between 3 and 5? tasks, but are able to recite multiplication tables and read or write numerals. Functional imaging studies of neurologically intact humans performing subtraction, number comparison, and nonverbal magnitude comparison tasks show activity in areas within the intraparietal sulcus. Taken together, clinical cases and imaging studies support a critical role for parietal cortex in the mental manipulation of numerical quantities. Further, responses of single PPC neurons in non-human primates are sensitive to the numerosity of visual stimuli independent of low-level stimulus qualities. When monkeys are trained to make explicit judgments about the numerical value of such stimuli, PPC neurons encode their cardinal numerical value; without such training PPC neurons appear to encode numerical magnitude in an analog fashion. Here we suggest that the spatial and integrative properties of PPC neurons contribute to their critical role in numerical cognition.

  3. Adult posterior urethral valve: a case report

    Science.gov (United States)

    Kilciler, Mete; Basal, Seref; Irkilata, Hasan Cem; Zor, Murat; Istanbulluoglu, Mustafa Okan; Dayanc, Murat

    2010-01-01

    Introduction: Posterior urethral valve (PUV) is a congenital obstructive defect of the male urethra with an incidence of 1/8,000 to 1/25,000 live births. PUV is the most common cause of lower urinary tract obstruction in neonates. The diagnosis of PUV is usually made early, and PUV cases have rarely been detected in adults. Case presentation: Here we report the case of a 35 years old man presented with obstructive urinary symptoms. In spite of bladder neck rejection uroflowmetry pointed out infravesical obstruction with max. flow rate 9 ml/s and average flow rate 6 ml/s in uroflowmetry. During cystoscopy mild bladder trabeculation and resected bladder neck were seen. While the cystoscope was taken off, PUV were obtained. Conclusion: Since PUV is a rare condition in adults and the diagnosis of PUVs is also difficult in these groups we must consider this situation during evaluation of adult patients with obstructive symptoms especially during cystourethroscopy. PMID:20379394

  4. Adult posterior urethral valve: a case report

    Directory of Open Access Journals (Sweden)

    Dayanc, Murat

    2010-03-01

    Full Text Available Introduction: Posterior urethral valve (PUV is a congenital obstructive defect of the male urethra with an incidence of 1/8,000 to 1/25,000 live births. PUV is the most common cause of lower urinary tract obstruction in neonates. The diagnosis of PUV is usually made early, and PUV cases have rarely been detected in adults. Case presentation: Here we report the case of a 35 years old man presented with obstructive urinary symptoms. In spite of bladder neck rejection uroflowmetry pointed out infravesical obstruction with max. flow rate 9 ml/s and average flow rate 6 ml/s in uroflowmetry. During cystoscopy mild bladder trabeculation and resected bladder neck were seen. While the cystoscope was taken off, PUV were obtained. Conclusion: Since PUV is a rare condition in adults and the diagnosis of PUVs is also difficult in these groups we must consider this situation during evaluation of adult patients with obstructive symptoms especially during cystourethroscopy.

  5. Posterior Reversible Leukoencephalopathy Syndrome Associated with Pazopanib

    Directory of Open Access Journals (Sweden)

    Robert Foerster

    2013-04-01

    Full Text Available A 62-year-old female patient with metastatic renal cell carcinoma under third-line treatment with pazopanib for 8 weeks suddenly developed severe headaches, grand mal seizures and paresis of the left arm in combination with gait instability as well as nausea and vomiting during her vacation abroad. The emergency physician measured systolic blood pressure values over 300 mm Hg and suspected a stroke. The CT imaging without contrast agent in a local hospital did not show any pathologic findings despite bone metastases. The colleagues suspected cerebral metastases or meningeosis carcinomatosa and referred the patient to our department for further diagnostics and treatment planning. An MRI scan ruled out the suspected cerebral metastases or meningeosis carcinomatosa, but showed signs of reversible posterior leukoencephalopathy syndrome (RPLS in the form of band-like hyperintensities as a sign of cytotoxic edema in the gray and white matter of the left parietal lobe. The patient then reported that similar blood pressure values had been measured shortly after the start of a first-line therapy with sunitinib, so that we discontinued the current treatment with pazopanib. Within 6 days the neurologic symptoms vanished and the patient was discharged. An intermittent hypertension persisted. A follow-up MRI 3 weeks later showed an RPLS-typical cortical infarction in the affected area. RPLS should be considered as the actual reason for neurologic findings in hypertensive patients with known metastatic cancers under tyrosine kinase inhibitor therapy.

  6. Facilitating text reading in posterior cortical atrophy.

    Science.gov (United States)

    Yong, Keir X X; Rajdev, Kishan; Shakespeare, Timothy J; Leff, Alexander P; Crutch, Sebastian J

    2015-07-28

    We report (1) the quantitative investigation of text reading in posterior cortical atrophy (PCA), and (2) the effects of 2 novel software-based reading aids that result in dramatic improvements in the reading ability of patients with PCA. Reading performance, eye movements, and fixations were assessed in patients with PCA and typical Alzheimer disease and in healthy controls (experiment 1). Two reading aids (single- and double-word) were evaluated based on the notion that reducing the spatial and oculomotor demands of text reading might support reading in PCA (experiment 2). Mean reading accuracy in patients with PCA was significantly worse (57%) compared with both patients with typical Alzheimer disease (98%) and healthy controls (99%); spatial aspects of passages were the primary determinants of text reading ability in PCA. Both aids led to considerable gains in reading accuracy (PCA mean reading accuracy: single-word reading aid = 96%; individual patient improvement range: 6%-270%) and self-rated measures of reading. Data suggest a greater efficiency of fixations and eye movements under the single-word reading aid in patients with PCA. These findings demonstrate how neurologic characterization of a neurodegenerative syndrome (PCA) and detailed cognitive analysis of an important everyday skill (reading) can combine to yield aids capable of supporting important everyday functional abilities. This study provides Class III evidence that for patients with PCA, 2 software-based reading aids (single-word and double-word) improve reading accuracy. © 2015 American Academy of Neurology.

  7. Bayesian posteriors for arbitrarily rare events.

    Science.gov (United States)

    Fudenberg, Drew; He, Kevin; Imhof, Lorens A

    2017-05-09

    We study how much data a Bayesian observer needs to correctly infer the relative likelihoods of two events when both events are arbitrarily rare. Each period, either a blue die or a red die is tossed. The two dice land on side [Formula: see text] with unknown probabilities [Formula: see text] and [Formula: see text], which can be arbitrarily low. Given a data-generating process where [Formula: see text], we are interested in how much data are required to guarantee that with high probability the observer's Bayesian posterior mean for [Formula: see text] exceeds [Formula: see text] times that for [Formula: see text] If the prior densities for the two dice are positive on the interior of the parameter space and behave like power functions at the boundary, then for every [Formula: see text] there exists a finite [Formula: see text] so that the observer obtains such an inference after [Formula: see text] periods with probability at least [Formula: see text] whenever [Formula: see text] The condition on [Formula: see text] and [Formula: see text] is the best possible. The result can fail if one of the prior densities converges to zero exponentially fast at the boundary.

  8. Cognitive Control Signals in Posterior Cingulate Cortex

    Directory of Open Access Journals (Sweden)

    Benjamin eHayden

    2010-12-01

    Full Text Available Efficiently shifting between tasks is a central function of cognitive control. The role of the default network—a constellation of areas with high baseline activity that declines during task performance—in cognitive control remains poorly understood. We hypothesized that task switching demands cognitive control to shift the balance of processing towards the external world, and therefore predicted that switching between the two tasks would require suppression of activity of neurons within the CGp. To test this idea, we recorded the activity of single neurons in posterior cingulate cortex (CGp, a central node in the default network, in monkeys performing two interleaved tasks. As predicted, we found that basal levels of neuronal activity were reduced following a switch from one task to another and gradually returned to pre-switch baseline on subsequent trials. We failed to observe these effects in lateral intraparietal cortex (LIP, part of the dorsal fronto-parietal cortical attention network directly connected to CGp. These findings indicate that suppression of neuronal activity in CGp facilitates cognitive control, and suggest that activity in the default network reflects processes that directly compete with control processes elsewhere in the brain..

  9. Space weathering trends on carbonaceous asteroids: A possible explanation for Bennu's blue slope?

    Science.gov (United States)

    Lantz, C.; Binzel, R. P.; DeMeo, F. E.

    2018-03-01

    We compare primitive near-Earth asteroid spectral properties to the irradiated carbonaceous chondrite samples of Lantz et al. (2017) in order to assess how space weathering processes might influence taxonomic classification. Using the same eigenvectors from the asteroid taxonomy by DeMeo et al. (2009), we calculate the principal components for fresh and irradiated meteorites and find that change in spectral slope (blueing or reddening) causes a corresponding shift in the two first principal components along the same line that the C- and X-complexes track. Using a sample of B-, C-, X-, and D-type NEOs with visible and near-infrared spectral data, we further investigated the correlation between prinicipal components and the spectral curvature for the primitive asteroids. We find that space weathering effects are not just slope and albedo, but also include spectral curvature. We show how, through space weathering, surfaces having an original "C-type" reflectance can thus turn into a redder P-type or a bluer B-type, and that space weathering can also decrease (and disguise) the D-type population. Finally we take a look at the case of OSIRIS-REx target (101955) Bennu and propose an explanation for the blue and possibly red spectra that were previously observed on different locations of its surface: parts of Bennu's surface could have become blue due to space weathering, while fresher areas are redder. No clear prediction can be made on Hayabusa-2 target (162173) Ryugu.

  10. Effects of heel base size, walking speed, and slope angle on center of pressure trajectory and plantar pressure when wearing high-heeled shoes.

    Science.gov (United States)

    Luximon, Yan; Cong, Yan; Luximon, Ameersing; Zhang, Ming

    2015-06-01

    High-heeled shoes are associated with instability and a high risk of fall, fracture, and ankle sprain. This study investigated the effects of heel base size (HBS) on walking stability under different walking speeds and slope angles. The trajectory of the center of pressure (COP), maximal peak pressure, pressure time integral, contact area, and perceived stability were analyzed. The results revealed that a small HBS increased the COP deviations, shifting the COP more medially at the beginning of the gait cycle. The slope angle mainly affected the COP in the anteroposterior direction. An increased slope angle shifted the COP posterior and caused greater pressure and a larger contact area in the midfoot and rearfoot regions, which can provide more support. Subjective measures on perceived stability were consistent with objective measures. The results suggested that high-heeled shoes with a small HBS did not provide stable plantar support, particularly on a small slope angle. The changes in the COP and pressure pattern caused by a small HBS might increase joint torque and muscle activity and induce lower limb problems. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Posterior Probability Matching and Human Perceptual Decision Making.

    Science.gov (United States)

    Murray, Richard F; Patel, Khushbu; Yee, Alan

    2015-06-01

    Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models' performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods provide new tools

  12. Posterior Probability Matching and Human Perceptual Decision Making.

    Directory of Open Access Journals (Sweden)

    Richard F Murray

    2015-06-01

    Full Text Available Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models' performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods

  13. Unusual combination of posterior femoral head dislocation with anterior and posterior wall fractures in the ipsilateral acetabulum.

    Science.gov (United States)

    Chen, Wei; Su, Yanling; Zhang, Yingze; Zhang, Qi; Zheng, Zhanle; Pan, Jinshe

    2010-06-09

    Although hip dislocation combined with acetabular fracture is not an uncommon injury, anterior acetabular wall fractures rarely occur in patients who have posterior fracture-dislocations of the hip. This article presents a unique case of anterior and posterior wall fractures of the ipsilateral acetabulum in a patient who sustained traumatic posterior hip dislocation that resulted from a high-speed motor vehicle accident. The initial imaging evaluation, which did not include the obturator oblique view, revealed no concomitant anterior acetabular wall fracture. Repeated manipulative reductions were unsuccessful in reducing the displaced hip joint. Pelvic computed tomography (CT) scans revealed the initially missed anterior acetabular wall fracture fragments incarcerated in the left hip joint in addition to the hip dislocation and the posterior acetabular wall fracture. The incarcerated bone fragments lay between the anterior wall and the femoral head, and between the posterior wall and the femoral head, which appeared to derive from both anterior and posterior acetabular walls, respectively. Open reduction and internal fixation was performed to manage the posterior dislocation and associated acetabular fractures. Intraoperatively, the major anterior wall fragment was used to reconstruct the defected posterior wall. This case highlights the necessity of suspicion and pre- and postoperative monitoring of the obturator oblique view and CT scans to detect the potentially existing anterior acetabular wall fracture. Early surgical intervention is important to guarantee satisfactory outcomes of such complex fracture-dislocation injuries. Copyright 2010, SLACK Incorporated.

  14. Combined Anterior-Posterior Surgery Versus Posterior Surgery for Thoracolumbar Burst Fractures: A Systematic Review of the Literature

    NARCIS (Netherlands)

    P.P. Oprel (Pim); W.E. Tuinebreijer (Wim); P. Patka (Peter); D. den Hartog (Dennis)

    2010-01-01

    textabstractAbstract: Study Design: A systematic quantitative review of the literature. Objective: To compare combined anterior-posterior surgery versus posterior surgery for thoracolumbar fractures in order to identify better treatments. Summary of Background Data: Axial load of the anterior and

  15. Development of the springbok skin - colour pattern, hair slope and ...

    African Journals Online (AJOL)

    S.-Afr. Tydskr. Dierk. 1989,24(1). Development of the springbok skin - colour pattern, hair slope and horn rudiments in Antidorcas marsupialis. G.H. Findlay. Department of Dermatology, Faculty of Medicine, University of Pretoria, Pretoria, 0001 Republic of South Africa·. Received 19 May 1988; accepted 8 September 1988.

  16. Stability analysis of sandy slope considering anisotropy effect in ...

    Indian Academy of Sciences (India)

    This paper aims to investigate the effect of anisotropy of shear strength parameter on the stability of a sandy slope by performing the limit equilibrium analysis. Because of scarcity of mathematical equation for anisotropic friction angle of sand, at first, all results of principal stress rotation tests are processed by artificial neural ...

  17. Experimental research on stability of covering blocks for sloping banks

    International Nuclear Information System (INIS)

    Okuno, Toshihiko

    1988-01-01

    In the case of constructing thermal and nuclear power stations facing open seas, usually the harbors for unloading fuel and others are constructed. In Japan, breakwaters are installed in the places of relatively shallow depth less than 20 m, and in such case, the sloping banks having the covering material of wave-controlling blocks made of concrete are mostly adopted as those are excellent in their function and economical efficiency, and are advantageous in the maintenance and management. Sloping banks are of such type that wave-controlling blocks cover the vertical front face of nonpermeating caissons, and the same type was adopted for breakwaters and others in Onagawa Nuclear Power Station, Tohoku Electric Power Co., Inc. As for the wave-controlling blocks, tetrapods and shake blocks were used. One of the most important problems in the design of sloping banks is how to estimate the stability of wave controlling blocks. In this paper, the results of the examination by hydraulic model experiment on the stability of covering blocks are reported, which are useful as the basic data for the rational and economical design of sloping banks. The experimental setup and a model bank, the generation of experimental waves and their characteristics, the experimental conditions and experimental method, and the results are reported. (Kako, I.)

  18. Wave Run-Up on Sloping Coastal Structures

    DEFF Research Database (Denmark)

    Rouck, J. De; Troch, P.; Ronde, J. De

    Wave run-up is one of the main physical processes which is taken into account in the design of the crest level of sloping coastal structures. Until recently, solely physical model results were used for the crest level design. However, prototype measurements have indicated that scale models...

  19. Nonlinear assessment of time series from rock slope monitoring

    Czech Academy of Sciences Publication Activity Database

    Zvelebil, J.; Paluš, Milan

    2007-01-01

    Roč. 9 (2007), A-05649 ISSN 1029-7006. [General Asembly of the European Geophysical Society. 15.04.2007-20.04.2007, Vienna] Institutional research plan: CEZ:AV0Z10300504 Keywords : fractal * scaling * unstable rock slope * collapse prediction * engineering geology Subject RIV: DG - Athmosphere Sciences, Meteorology

  20. the Modeling of Hydraulic Jump Generated Partially on Sloping Apron

    Directory of Open Access Journals (Sweden)

    Shaker Abdulatif Jalil

    2017-12-01

    Full Text Available Modeling aims to characterize system behavior and achieve simulation close as possible of the reality. The rapid energy exchange in supercritical flow to generate quiet or subcritical flow in hydraulic jump phenomenon is important in design of hydraulic structures. Experimental and numerical modeling is done on type B hydraulic jump which starts first on sloping bed and its end on horizontal bed.  Four different apron slopes are used, for each one of these slopes the jump is generated on different locations by controlling the tail water depth.  Modelling validation is based on 120 experimental runs which they show that there is reliability. The air volume fraction which creates in through hydraulic jump varied between 0.18 and 0.28. While the energy exchanges process take place within 6.6, 6.1, 5.8, 5.5 of the average relative jump height for apron slopes of 0.18, 0.14, 0.10, 0.07 respectively. Within the limitations of this study, mathematical prediction model for relative hydraulic jump height is suggested.The model having an acceptable coefficient of determination.

  1. Soil erosion and management activities on forested slopes

    Science.gov (United States)

    Robert R. Ziemer

    1986-01-01

    Some of the most productive forests in the Western United States grow on marginally stable mountainous slopes, where disturbance increases the likelihood of erosion. Much of the public's concern about, and, consequently, most of the research on, erosion from these forested areas is related more to the degradation of stream resources by eroded material than to the...

  2. Erosion protection for soil slopes along Virginia's highways.

    Science.gov (United States)

    2000-01-01

    A survey of the state of practice for designing slope erosion control measures within VDOT's nine districts has been conducted. On the basis of the survey, it is clear that there are no specific design procedures currently in use within VDOT for deal...

  3. Effect of Angle of Attack on Slope Climbing Performance

    Science.gov (United States)

    Creager, Colin M.; Jones, Lucas; Smith, Lauren M.

    2017-01-01

    Ascending steep slopes is often a very difficult challenge for off-road vehicles, whether on Earth or on extraterrestrial bodies. This challenge is even greater if the surface consists of loose granular soil that does not provide much shear strength. This study investigated how the path at which a vehicle traverses a slope, specifically the angle that it is commanded to drive relative to the base of the hill (the angle of attack), can affect its performance. A vehicle was driven in loose sand at slope angles up to 15 degrees and angles of attack ranging from 10 to 90 degrees. A novel photogrammetry technique was implemented to both track vehicle motion and create a three-dimensional profile of the terrain. This allowed for true wheel sinkage measurements. The study showed that though low angles of attack result in lower wheel slip and sinkage, the efficiency of the vehicles uphill motion increased at higher angles of attack. For slopes up to 15 degrees, a 90 degree angle of attack provided the greatest likelihood of successful ascent.

  4. End depth in steeply sloping rough rectangular channels

    Indian Academy of Sciences (India)

    Conte S D, de Boor C 1987 Elementary numerical analysis: An algorithmic approach (New York: McGraw-Hill). Davis A C, Ellett B G S, Jacob R P 1998 Flow measurement in sloping channels with rectangular free overfall. J. Hydraul. Eng., Am. Soc. Civ. Eng. 124: 760±763. Davis A C, Jacob R P, Ellett B G S 1999 Estimating ...

  5. Title Qualitative stability assessment of cut slopes along the national ...

    Indian Academy of Sciences (India)

    64

    Monitoring: ISRM Suggested Methods. Pergamon Press, London. Kundu J, Sarkar K, Singh AK (2016) Integrating structural and numerical solutions for road cut slope stability analysis-A case study, India. Rock Dynamics: From Research to. Engineering: Proceedings of the 2nd International Conference on Rock Dynamics ...

  6. Spider (Araneae) communities of scree slopes in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Růžička, Vlastimil; Klimeš, Leoš

    2005-01-01

    Roč. 33, č. 2 (2005), s. 280-289 ISSN 0161-8202 R&D Projects: GA AV ČR(CZ) IAA6007401 Institutional research plan: CEZ:AV0Z50070508; CEZ:AV0Z6005908 Keywords : scree slopes * environmental factors * ice formation Subject RIV: EG - Zoology Impact factor: 0.557, year: 2005

  7. Data compression by a decreasing slope-threshold test

    Science.gov (United States)

    Kleinrock, L.

    1973-01-01

    Resolution can be obtained at large compression ratios with method for selecting data points for transmission by telemetry in television compressed-data system. Test slope of raw data stream and compare it to symmetric pair of decreasing thresholds. When either threshold is exceeded, data are sampled and transmitted; thresholds are reset, and test begins again.

  8. Oscillating Nocturnal Slope Flow in a Coastal Valley

    DEFF Research Database (Denmark)

    Gryning, Sven-Erik; Larsen, Søren Ejling; Mahrt, Larry

    1985-01-01

    Observations of slope flows in a coastal valley are analyzed. The diurnal variation of upslope and downslope flows depends on season in a systematic way which appears to be related to the high latitude of the observational site and the presence of a nearby layer of marine air. Summer nocturnal flow...

  9. Air quality in bedded mono-slope beef barns

    Science.gov (United States)

    Bedded mono-slope barns are becoming more common in the upper Midwest. Because these are new facilities, little research has been published regarding environmental quality, building management and animal performance in these facilities. A team of researchers from South Dakota State University, USDA ...

  10. How the spatial variation of tree roots affects slope stability

    Science.gov (United States)

    Mao, Zhun; Stokes, A.; Jourdan, C.; Rey, H.; Courbaud, B.; Saint-André, L.

    2010-05-01

    It is now widely recognized that plant roots can reinforce soil against shallow mass movement. Although studies on the interactions between vegetation and slope stability have significantly augmented in recent years, a clear understanding of the spatial dynamics of root reinforcement (through additional cohesion by roots) in subalpine forest is still limited, especially with regard to the roles of different forest management strategies or ecological landscapes. The architecture of root systems is important for soil cohesion, but in reality it is not possible to measure the orientation of each root in a system. Therefore, knowledge on the effect of root orientation and anisotropy on root cohesion on the basis of in situ data is scanty. To determine the effect of root orientation in root cohesion models, we investigated root anisotropy in two mixed, mature, naturally regenerated, subalpine forests of Norway spruce (Picea abies), and Silver fir (Abies alba). Trees were clustered into islands, with open spaces between each group, resulting in strong mosaic heterogeneity within the forest stand. Trenches within and between clusters of trees were dug and root distribution was measured in three dimensions. We then simulated the influence of different values for a root anisotropy correction factor in forests with different ecological structures and soil depths. Using these data, we have carried out simulations of slope stability by calculating the slope factor of safety depending on stand structure. Results should enable us to better estimate the risk of shallow slope failure depending on the type of forest and species.

  11. Slope Stability Analysis Using Slice-Wise Factor of Safety

    Directory of Open Access Journals (Sweden)

    Yu Zhao

    2014-01-01

    Full Text Available The concept of slice-wise factor of safety is introduced to investigate the state of both the whole slope and each slice. The assumption that the interslice force ratio is the same between any two slices is made and the eccentric moment of slice weight is also taken into account. Then four variables equations are formulated based on the equilibrium of forces and moment and the assumption of interslice forces, and then the slice-wise factor of safety along the slip surface can be obtained. The active and passive sections of the slope can be determined based on the distribution of factor of safety. The factor of safety of the whole slope is also defined as the ratio of the sum of antisliding force to the sum of sliding force on the slip surface. Two examples with different slip surface shapes are analysed to demonstrate the usage of the proposed method. The slice-wise factor of safety enables us to determine the sliding mechanism and pattern of a slope. The reliability is verified by comparing the overall factor of safety with that calculated by conventional methods.

  12. Slope histogram distribution-based parametrisation of Martian geomorphic features

    Science.gov (United States)

    Balint, Zita; Székely, Balázs; Kovács, Gábor

    2014-05-01

    The application of geomorphometric methods on the large Martian digital topographic datasets paves the way to analyse the Martian areomorphic processes in more detail. One of the numerous methods is the analysis is to analyse local slope distributions. To this implementation a visualization program code was developed that allows to calculate the local slope histograms and to compare them based on Kolmogorov distance criterion. As input data we used the digital elevation models (DTMs) derived from HRSC high-resolution stereo camera image from various Martian regions. The Kolmogorov-criterion based discrimination produces classes of slope histograms that displayed using coloration obtaining an image map. In this image map the distribution can be visualized by their different colours representing the various classes. Our goal is to create a local slope histogram based classification for large Martian areas in order to obtain information about general morphological characteristics of the region. This is a contribution of the TMIS.ascrea project, financed by the Austrian Research Promotion Agency (FFG). The present research is partly realized in the frames of TÁMOP 4.2.4.A/2-11-1-2012-0001 high priority "National Excellence Program - Elaborating and Operating an Inland Student and Researcher Personal Support System convergence program" project's scholarship support, using Hungarian state and European Union funds and cofinances from the European Social Fund.

  13. Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

    2008-08-15

    Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

  14. 30 CFR 716.2 - Steep-slope mining.

    Science.gov (United States)

    2010-07-01

    ... original contour restoration requirements. (1) This section applies to surface coal mining operations on... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Steep-slope mining. 716.2 Section 716.2 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL PROGRAM...

  15. Stability analysis of sandy slope considering anisotropy effect in ...

    Indian Academy of Sciences (India)

    1Faculty of Engineering, Azarbaijan Shahid Madani University, ... 2School of Civil Engineering, Iran University of Science and Technology, ..... material. 4.3 Stability analysis result. For each analysis case with specified geometrical configuration for slope, a wide range of slip surfaces are considered by establishing a grid of ...

  16. Soil conservation options for olive orchards on sloping land

    NARCIS (Netherlands)

    Fleskens, L.; Graaff, de J.

    2003-01-01

    Olive production is an important and growing agricultural activity throughout the Meditteranean zone. At the same time, soil erosion is one of the environmental key problems in this zone. Actual erosion in olive production areas is high, in particular on sloping land. Several erosion risk factors

  17. Slope failure susceptibility zonation using integrated remote sensing ...

    Indian Academy of Sciences (India)

    61

    The susceptibility of slopes in open pit coal mines to various modes of failure (i.e. plane, wedge, circular and toppling failure) could be envisaged by virtue of processing and analysis of pertinent satellite data. The aim of the present study was to integrate thematic maps generated using remote sensing image processing ...

  18. Title Qualitative stability assessment of cut slopes along the national ...

    Indian Academy of Sciences (India)

    64

    Keeping an eye to above problems, a study was carried out along NH-05 covering a stretch of 12 km from Jhakri to Jeori ... 2016). Regional strike of lithological units is ENE-WSW which shows local variations in the trend (Singh 1979). .... Slope 3 is exposed to wedge failure and trend of the intersection line is towards 301°.

  19. Postural Stability Margins as a Function of Support Surface Slopes.

    Directory of Open Access Journals (Sweden)

    Aviroop Dutt-Mazumder

    Full Text Available This investigation examined the effects of slope of the surface of support (35°, 30°, 20°, 10° Facing(Toe Down, 0° Flat and 10°, 20°, 25° Facing (Toe Up and postural orientation on the margins of postural stability in quiet standing of young adults. The findings showed that the center of pressure-CoP (displacement, area and length had least motion at the baseline (0° Flat platform condition that progressively increased as a function of platform angle in both facing up and down directions. The virtual time to collision (VTC dynamics revealed that the spatio-temporal margins to the functional stability boundary were progressively smaller and the VTC time series also more regular (SampEn-Sample Entropy as slope angle increased. Surface slope induces a restricted stability region with lower dimension VTC dynamics that is more constrained when postural orientation is facing down the slope. These findings provide further evidence that VTC acts as a control variable in standing posture that is influenced by the emergent dynamics of the individual-environment-task interaction.

  20. Infiltration on mountain slopes: a comparison of three environments.

    Science.gov (United States)

    Carol P. Harden*; P. Delmas Scruggs

    2003-01-01

    Water is well established as a major driver of the geomorphic change that eventually reduces mountains to lower relief landscapes. Nonetheless, within the altitudinal limits of continuous vegetation in humid climates, water is also an essential factor in slope stability. In this paper, we present results from field experiments to determine infiltration rates at...

  1. 30 CFR 785.15 - Steep slope mining.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Steep slope mining. 785.15 Section 785.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR SURFACE COAL MINING AND RECLAMATION OPERATIONS PERMITS AND COAL EXPLORATION SYSTEMS UNDER REGULATORY PROGRAMS...

  2. Challenging conservation agriculture on marginal slopes in Sehoul, Morocco

    NARCIS (Netherlands)

    Schwilch, G.; Laouina, A.; Chaker, M.; Machouri, N.; Sfa, M.; Stroosnijder, L.

    2015-01-01

    In Sehoul, Morocco, the use of marginal land for agriculture became a necessity for the local population due to increased poverty and the occupation of the best land by new owners. Desertification poses an additional threat to agricultural production on marginal slopes, which are often stony and

  3. A global safety deficiency : False glide slope capture affecting aircraft

    NARCIS (Netherlands)

    Schuurman, M.J.

    2016-01-01

    A serious incident occurred at Eindhoven Airport (Netherlands) in May 2013. A Boeing 737-800 performed a go-around while using the Instrument Landing System (ILS). The flight crew reported a False Glide Slope capture as the reason for the go-around.
    At first the occurrence report did not really

  4. Interannual variability in the skate assemblage on the South Patagonian shelf and slope.

    Science.gov (United States)

    Winter, A; Pompert, J; Arkhipkin, A; Brewin, P E

    2015-12-01

    Observer data from the commercial fishery on the Patagonian shelf and slope around the Falkland Islands (home to an assemblage of >16 skate species (Rajiformes), for which commercial catches have been recorded since 1987), as well as survey data from an area closed to skate target fishing after exploitation, were summarized by species to examine changes in the population status of individual skate species. Total skate catch per unit effort increased significantly in the target fishery since 1994, and four species have made up >85% of all skate catch. Bathyraja brachyurops and Zearaja chilensis increased significantly in catch proportions and abundance from 1994 to 2013. Bathyraja albomaculata and Bathyraja griseocauda decreased significantly before rebounding with trends of increasing abundance. Concurrently, B. brachyurops and Z. chilensis showed decreasing trends in size at 50% maturity in areas where skates continue to be targeted commercially. The increasing abundances and concomitant reductions in size at maturity of B. brachyurops and Z. chilensis suggest either plasticity in life-history traits or a density-dependent growth response to fishing pressure. Bathyraja griseocauda decreased in size at 50% maturity in the area that was closed to skate target fishing, where it was initially larger, but only decreased to the same average size as in the commercially targeted areas. Bathyraja albomaculata and Z. chilensis are IUCN-listed as vulnerable and B. griseocauda is listed as endangered, but their abundance trends since 1994 indicate that these populations are not declining in Falkland waters. © 2015 The Fisheries Society of the British Isles.

  5. Ultrasonographic findings of posterior interosseous nerve syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kim, You Dong; Ha, Doo Hoe; Lee, Sang Min [Dept. of Radiology, CHA Bundang Medical Center, CHA University, Seongnam (Korea, Republic of)

    2017-10-15

    The purpose of this study was to evaluate the ultrasonographic findings associated with posterior interosseous nerve (PIN) syndrome. Approval from the Institutional Review Board was obtained. A retrospective review of 908 patients' sonographic images of the upper extremity from January 2001 to October 2010 revealed 10 patients suspicious for a PIN abnormality (7 male and 3 female patients; mean age of 51.8±13.1 years; age range, 32 to 79 years). The ultrasonographic findings of PIN syndrome, including changes in the PIN and adjacent secondary changes, were evaluated. The anteroposterior diameter of the pathologic PIN was measured in eight patients and the anteroposterior diameter of the contralateral asymptomatic PIN was measured in six patients, all at the level immediately proximal to the proximal supinator border. The size of the pathologic nerves and contralateral asymptomatic nerves was compared using the Mann-Whitney U test. Swelling of the PIN proximal to the supinator canal by compression at the arcade of Fröhse was observed in four cases. Swelling of the PIN distal to the supinator canal was observed in one case. Loss of the perineural fat plane in the supinator canal was observed in one case. Four soft tissue masses were noted. Secondary denervation atrophy of the supinator and extensor muscles was observed in two cases. The mean anteroposterior diameter of the pathologic nerves (n=8, 1.79±0.43 mm) was significantly larger than that of the contralateral asymptomatic nerves (n=6, 1.02±0.22 mm) (P=0.003). Ultrasonography provides high-resolution images of the PIN and helps to diagnose PIN syndrome through visualization of its various causes and adjacent secondary changes.

  6. Visual neglect in posterior cortical atrophy

    Directory of Open Access Journals (Sweden)

    Andrade Katia

    2010-08-01

    Full Text Available Abstract Background In posterior cortical atrophy (PCA, there is a progressive impairment of high-level visual functions and parietal damage, which might predict the occurrence of visual neglect. However, neglect may pass undetected if not assessed with specific tests, and might therefore be underestimated in PCA. In this prospective study, we aimed at establishing the side, the frequency and the severity of visual neglect, visual extinction, and primary visual field defects in an unselected sample of PCA patients. Methods Twenty-four right-handed PCA patients underwent a standardized battery of neglect tests. Visual fields were examined clinically by the confrontation method. Results Sixteen of the 24 patients (66% had signs of visual neglect on at least one test, and fourteen (58% also had visual extinction or hemianopia. Five patients (21% had neither neglect nor visual field defects. As expected, left-sided neglect was more severe than right-sided neglect. However, right-sided neglect resulted more frequently in this population (29% than in previous studies on focal brain lesions. Conclusion When assessed with specific visuospatial tests, visual neglect is frequent in patients with PCA. Diagnosis of neglect is important because of its negative impact on daily activities. Clinicians should consider the routine use of neglect tests to screen patients with high-level visual deficits. The relatively high frequency of right-sided neglect in neurodegenerative patients supports the hypothesis that bilateral brain damage is necessary for right-sided neglect signs to occur, perhaps because of the presence in the right hemisphere of crucial structures whose damage contributes to neglect.

  7. Anterior Commissure-posterior commissure revisited

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Han; Chi, Je Geun; Kim, Young Bo; Cho, Zang Hee [Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of)

    2013-08-15

    The anterior commissure (AC) and posterior commissure (PC) are the two distinct anatomic structures in the brain which are difficult to observe in detail with conventional MRI, such as a 1.5T MRI system. However, recent advances in ultra-high resolution MRI have enabled us to examine the AC and PC directly. The objective of the present study is to standardize the shape and size of the AC and PC using a 7.0T MRI and to propose a new brain reference line. Thirty-four, 21 males and 13 females, healthy volunteers were enrolled in this study. After determining the center of each AC and PC, we defined the connection of these centers as the central intercommissural line (CIL). We compared the known extra- and intra-cerebral reference lines with the CIL to determine the difference in the angles. Additionally, we obtained horizontal line from flat ground line of look front human. The difference in angle of the CIL and the tangential intercommissural line (TIL) from the horizontal line was 8.7 ± 5.1 (11 ± 4.8) and 17.4 ± 5.2 (19.8 ± 4.8) degrees in males and females, respectively. The difference in angle between the CIL and canthomeatal line was 10.1 in both male and female, and there was no difference between both sexes. Likewise, there was no significant difference in angle between the CIL and TIL between both sexes (8.3 +/- 1.1 in male and 8.8 +/- 0.7 in female). In this study, we have used 7.0T MRI to define the AC and PC quantitatively and in a more robust manner. We have showed that the CIL is a reproducible reference line and serves as a standard for the axial images of the human brain.

  8. Posterior or Single-stage Combined Anterior and Posterior Approach Decompression for Treating Complex Cervical Spondylotic Myelopathy Coincident Multilevel Anterior and Posterior Compression.

    Science.gov (United States)

    Zhou, Xiaoxiao; Cai, Pan; Li, Yuwei; Wang, Haijiao; Xia, Shengli; Wang, Xiuhui

    2017-12-01

    A single-center, retrospective, longitudinal matched cohort clinical study of prospectively collected outcomes. To compare retrospectively the clinical outcomes and complications of the posterior approach laminoplasty and single-stage anterior approach laminoplasty combined with anterior cervical corpectomy and fusion and anterior cervical discectomy and fusion for treating patients with cervical spondylotic myelopathy coincident multilevel anterior and posterior compression, known as complex cervical spondylotic myelopathy (cCSM) here. The optimal surgical management of this type of cCSM remains controversial. Sixty-seven patients with multilevel cCSM underwent decompression surgery from 1996 to 2007. Among these patients, 31 underwent a single-stage combined approach with decompression (combined approach group) and 36 underwent laminoplasty for posterior approach (posterior approach group). Average operative duration, operative estimated blood loss, surgical costs, and cervical alignment were measured. Average operative duration, operative estimated blood loss, and surgical costs were significantly lower in the posterior approach group than those in the combined approach group (P0.05). No statistical difference was observed in the preoperative Cobb angle (P>0.05), whereas a significant statistical difference was observed for the postoperative Cobb angle (Pgroups. The surgical incidences of complications were 22.2% and 48.4% in the posterior and combined approach groups (Papproach laminoplasty and single-stage combined approach led to significant neurological improvement and pain reduction in the majority of patients. Both approaches showed similar results in terms of decompression and neurological improvement. The posterior approach was superior to the combined approach in terms of surgical costs, surgical time, blood loss, and complication rate.

  9. A new vision of carbonate slopes: the Little Bahama Bank

    Science.gov (United States)

    Mulder, Thierry; Gillet, Hervé; Hanquiez, Vincent; Reijmer, John J.; Tournadour, Elsa; Chabaud, Ludivine; Principaud, Mélanie; Schnyder, Jara; Borgomano, Jean

    2015-04-01

    Recent data collected in November 2014 (RV Walton Smith) on the upper slope of the Little Bahama Bank (LBB) between 30 and 400 m water depth allowed to characterize the uppermost slope (Rankey et al., 2012) over a surface of 170 km2. The new data set includes multibeam bathymetry and acoustic imagery, 3.5 kHz very-high resolution (VHR) seismic reflection lines, 21 gravity cores and 11 Van Veen grabs. The upper slope of the LBB does not show a steep submarine cliff as known from western Great Bahama Bank. The carbonate bank progressively deepens towards the basin through a slighty inclined plateau. The slope value is reef rests on paleo-reefs that outcrop at a water depth of about 40 m. These paleo-reef structures could represent reefs that established themselves during past periods of sea-level stagnation. Below this water depth, the slope steepens up to 30° to form the marginal escarpment (Rankey et al., 2012), which is succeeded by the open margin realm (Rankey et al., 2012). The slope inclination value decreases at about 180-200 m water depth. Between 20 and 200 m of water depth, the VHR seismic shows no seafloor sub-bottom reflector. Between 180 and 320 m water depth, the seafloor smoothens. The VHR seismic shows an onlapping sediment wedge, which starts in this water depth and shows a blind or very crudely stratified echo facies. The sediment thickness of this Holocene unit may exceed 20 m. It fills small depressions in the substratum and thickens in front of gullies that cut the carbonate platform edge. Sediment samples show the abundancy of carbonate mud on the present Bahamian seafloor. In gullies, coarser sediment can be found. In some case, soft sediments are absent suggesting by-passing. At water depth between 40 and 100 m, the present-day seafloor is covered with bioclastic sediments. The main carbonate producer seems to be the alga genus Halimeda. Sediments collected in the deeper part of the basin (water depth = 1080 m) on the distal lobe consist of

  10. CT findings of traumatic posterior hip dislocation after reduction

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Sung Kyoung; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook [Kyung Hee University Medical Center, Seoul (Korea, Republic of); Jin Wook

    2008-06-15

    To evaluate the CT images of reduced hips after posterior hip dislocation and to propose specific diagnostic criteria based on the CT results. We retrospectively reviewed the CT findings on 18 reduced hips from 17 patients with radiographs and clinical histories of traumatic posterior hip dislocations by evaluating 18 corresponding CT scans for joint space asymmetry, intra-articular abnormalities (intra-articular fat obliteration, loose bodies, and joint effusion), changes in posterior soft tissue (capsule, muscles, and adjacent fat), the presence, and location of fractures (acetabulum and femoral head). All 18 hips (100%) showed posterior soft tissue changes. In total, 17 hips (94.4%) had intra-articular abnormalities and 15 hips (83.3%) had joint space asymmetries. In addition, 17 hips (94.4%) had fractures involving the acetabula (15 cases, 88.2%) the femoral head (13 cases, 76.5%), or on both sides (11 cases, 64.7%). The most frequent fracture location was in he posterior wall (13/15, 86.7%) of the acetabulum and in the anterior aspect (10/13, 76.9%) of the femoral head. Patients with a prior history of posterior hip dislocation showed specific CT findings after reduction, suggesting the possibility of previous posterior hip dislocations in patients.

  11. CT findings of traumatic posterior hip dislocation after reduction

    International Nuclear Information System (INIS)

    Moon, Sung Kyoung; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook; Jin Wook

    2008-01-01

    To evaluate the CT images of reduced hips after posterior hip dislocation and to propose specific diagnostic criteria based on the CT results. We retrospectively reviewed the CT findings on 18 reduced hips from 17 patients with radiographs and clinical histories of traumatic posterior hip dislocations by evaluating 18 corresponding CT scans for joint space asymmetry, intra-articular abnormalities (intra-articular fat obliteration, loose bodies, and joint effusion), changes in posterior soft tissue (capsule, muscles, and adjacent fat), the presence, and location of fractures (acetabulum and femoral head). All 18 hips (100%) showed posterior soft tissue changes. In total, 17 hips (94.4%) had intra-articular abnormalities and 15 hips (83.3%) had joint space asymmetries. In addition, 17 hips (94.4%) had fractures involving the acetabula (15 cases, 88.2%) the femoral head (13 cases, 76.5%), or on both sides (11 cases, 64.7%). The most frequent fracture location was in he posterior wall (13/15, 86.7%) of the acetabulum and in the anterior aspect (10/13, 76.9%) of the femoral head. Patients with a prior history of posterior hip dislocation showed specific CT findings after reduction, suggesting the possibility of previous posterior hip dislocations in patients

  12. Land Use Suitability Assessment in Low-Slope Hilly Regions under the Impact of Urbanization in Yunnan, China

    Directory of Open Access Journals (Sweden)

    Gui Jin

    2015-01-01

    Full Text Available Nowadays, the conflict between land development and land conservation has become increasingly serious in China. The plan called “town of mountain” is carried out in many nonplain areas to alleviate the conflict. To avoid geological disasters and ecological risks in those areas, land use suitability assessment is of great importance. In this paper, the fuzzy weight of evidence model is applied into land use suitability assessment in low-slope hilly regions in Yunnan, China. Fuzzy weight of evidences is calculated to determine 9 map layers. Finally, posterior probabilities are modified after synthesizing each map layer, which are used to generate a land use suitability map. The results show that 9.33%, 26.18%, 45.98%, and 18.51% of low-slope hilly regions are separately highly suitable, moderately suitable, marginally suitable, and unsuitable for development. Besides, highly and moderately suitable areas are mainly located in towns with excellent natural and socioeconomic conditions. The largest areas which are marginally suitable for development are most widely distributed. Unsuitable areas are mainly distributed far away from towns and water sources. The findings of the research will promote the rational use and scientific management of the land.

  13. Bony landmark between the attachment of the medial meniscus posterior root and the posterior cruciate ligament: CT and MR imaging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Masataka; Furumatsu, Takayuki; Miyazawa, Shinichi; Kodama, Yuya; Hino, Tomohito; Kamatsuki, Yusuke; Ozaki, Toshifumi [Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Department of Orthopaedic Surgery, Science of Functional Recovery and Reconstruction, Okayama (Japan)

    2017-08-15

    (1) To reveal the prevalence of the bony recess (posterior dimple) and (2) to determine the position of the posterior dimple on the tibial plateau using three-dimensional computed tomography (3DCT). In this study, a retrospective review of 112 patients was performed to identify the posterior dimple and to evaluate its position on 3DCT. Magnetic resonance images (MRIs) were also used to determine the positional relationship among the posterior cruciate ligament (PCL), medial meniscus posterior insertion (MMPI), and posterior dimple. The posterior dimple was observed in 100 of 112 knees (89.3%) on 3DCT. The center of the posterior dimple was 13.6 ± 0.8 mm from the medial tibial eminence apex. MRI showed that the posterior dimple separated the tibial attachment of the PCL and MMPI. This is the first study to discuss the prevalence and position of the bony recess in the posterior intercondylar fossa. (orig.)

  14. The 137Cs technique applied to steep Mediterranean slopes (Part I): the effects of lithology, slope morphology and land use

    NARCIS (Netherlands)

    Schoorl, J.M.; Boix Fayos, C.; Meijer, de R.J.; Graaff, van der E.R.; Veldkamp, A.

    2004-01-01

    Concentrations in the soil of anthropogenic and natural radionuclides have been investigated in order to assess the applicability of the Cs-137 technique in an area of typical Mediterranean steep slopes. This technique can be used to estimate net soil redistribution rates but its potential in areas

  15. The Cs-137 technique applied to steep Mediterranean slopes (Part I) : the effects of lithology, slope morphology and land use

    NARCIS (Netherlands)

    de Meijer, R.J.; van der Graaf, E.R.

    2004-01-01

    Concentrations in the soil of anthropogenic and natural radionuclides have been investigated in order to assess the applicability of the Cs-137 technique in an area of typical Mediterranean steep slopes. This technique can be used to estimate net soil redistribution rates but its potential in areas

  16. Cooperative Three-Robot System for Traversing Steep Slopes

    Science.gov (United States)

    Stroupe, Ashley; Huntsberger, Terrance; Aghazarian, Hrand; Younse, Paulo; Garrett, Michael

    2009-01-01

    Teamed Robots for Exploration and Science in Steep Areas (TRESSA) is a system of three autonomous mobile robots that cooperate with each other to enable scientific exploration of steep terrain (slope angles up to 90 ). Originally intended for use in exploring steep slopes on Mars that are not accessible to lone wheeled robots (Mars Exploration Rovers), TRESSA and systems like TRESSA could also be used on Earth for performing rescues on steep slopes and for exploring steep slopes that are too remote or too dangerous to be explored by humans. TRESSA is modeled on safe human climbing of steep slopes, two key features of which are teamwork and safety tethers. Two of the autonomous robots, denoted Anchorbots, remain at the top of a slope; the third robot, denoted the Cliffbot, traverses the slope. The Cliffbot drives over the cliff edge supported by tethers, which are payed out from the Anchorbots (see figure). The Anchorbots autonomously control the tension in the tethers to counter the gravitational force on the Cliffbot. The tethers are payed out and reeled in as needed, keeping the body of the Cliffbot oriented approximately parallel to the local terrain surface and preventing wheel slip by controlling the speed of descent or ascent, thereby enabling the Cliffbot to drive freely up, down, or across the slope. Due to the interactive nature of the three-robot system, the robots must be very tightly coupled. To provide for this tight coupling, the TRESSA software architecture is built on a combination of (1) the multi-robot layered behavior-coordination architecture reported in "An Architecture for Controlling Multiple Robots" (NPO-30345), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 65, and (2) the real-time control architecture reported in "Robot Electronics Architecture" (NPO-41784), NASA Tech Briefs, Vol. 32, No. 1 (January 2008), page 28. The combination architecture makes it possible to keep the three robots synchronized and coordinated, to use data

  17. Model slope infiltration experiments for shallow landslides early warning

    Science.gov (United States)

    Damiano, E.; Greco, R.; Guida, A.; Olivares, L.; Picarelli, L.

    2009-04-01

    Occurrence of fast landslides has become more and more dangerous during the last decades, due to the increased density of settlements, industrial plants and infrastructures. Such problem is particularly worrying in Campania (Southern Italy), where the fast population growth led a diffuse building activity without planning: indeed, recent flowslides caused hundreds of victims and heavy damages to buildings, roads and other infrastructures. Large mountainous areas in Campania are mantled by loose pyroclastic granular soils up to a depth of a few meters from top soil surface. These soils have usually a grain size that falls in the domain of silty sands, including pumice interbeds (gravelly sands), with saturated hydraulic conductivities up to the order of 10-1 cm/min. Such deposits often cover steep slopes, which stability is guaranteed by the apparent cohesion due to suction under unsaturated conditions, that are the most common conditions for these slopes [Olivares and Picarelli, 2001]. Whereas rainfall infiltration causes soil to approach saturation, suction vanishes and slope failure may occur. Besides soil physical properties, landslide triggering is influenced by several factors, such as rainfall intensity, soil initial moisture and suction, slope inclination, boundary conditions. Whereas slope failure occurs with soil close to being saturated, landslide may develop in form of fast and destructive flowslide. Calibration of reliable mathematical models of such a complex phenomenon requires availability of experimental observations of the major variables of interest, such as soil moisture and suction, soil deformation and displacements, pore water pressure, during the entire process of infiltration until slope failure. Due to the sudden trigger and extremely rapid propagation of such type of landslides, such data sets are rarely available for natural slopes where flowslides occurred. As a consequence landslide risk assessment and early warning in Campania rely on

  18. An otx/nodal regulatory signature for posterior neural development in ascidians.

    Directory of Open Access Journals (Sweden)

    Agnès Roure

    2014-08-01

    Full Text Available In chordates, neural induction is the first step of a complex developmental process through which ectodermal cells acquire a neural identity. In ascidians, FGF-mediated neural induction occurs at the 32-cell stage in two blastomere pairs, precursors respectively of anterior and posterior neural tissue. We combined molecular embryology and cis-regulatory analysis to unveil in the ascidian Ciona intestinalis the remarkably simple proximal genetic network that controls posterior neural fate acquisition downstream of FGF. We report that the combined action of two direct FGF targets, the TGFβ factor Nodal, acting via Smad- and Fox-binding sites, and the transcription factor Otx suffices to trigger ascidian posterior neural tissue formation. Moreover, we found that this strategy is conserved in the distantly related ascidian Phallusia mammillata, in spite of extreme sequence divergence in the cis-regulatory sequences involved. Our results thus highlight that the modes of gene regulatory network evolution differ with the evolutionary scale considered. Within ascidians, developmental regulatory networks are remarkably robust to genome sequence divergence. Between ascidians and vertebrates, major fate determinants, such as Otx and Nodal, can be co-opted into different networks. Comparative developmental studies in ascidians with divergent genomes will thus uncover shared ascidian strategies, and contribute to a better understanding of the diversity of developmental strategies within chordates.

  19. Physical model studies of seismically induced deformations in slopes

    Science.gov (United States)

    Wartman, Joseph

    Physical model experiments were conducted on a 1-g shaking table with the goals of: (1) investigating the mechanisms of seismically induced permanent deformations in slopes and embankments, (2) assessing the accuracy and applicability of the popular "Newmark-type" procedures for estimating deformations in slopes, and (3) developing a suite of fully defined "model-scale" case histories for calibration of existing numerical procedures for predicting seismic slope deformations and for the future development of advanced numerical analyses. The inclined plane experiments indicated that the Newmark (1965) sliding block procedure generally provides unconservative estimates of deformation when the predominant frequency of the input motion is 0.2 to 1.5 times the natural frequency of the sliding mass. Conversely, the procedure was found to be generally conservative when the frequency ratio is in the range of about 1.5 to 2.2. The inclined plane tests also suggest that one-dimensional decoupled deformation analyses are generally conservative, with decoupled analyses overpredicting measured deformations by about 10% to 20% for the tests analyzed. The model slopes were commonly observed to displace along two or more localized shear surfaces. The multiple shear surfaces were typically of the same orientation and generally located within relatively close proximity of each other. Surface deformations varied over the length of each model, with the largest displacements occurring at the toe or along the face of the slope. Newmark's (1965) assumption that deformation occurs along a single surface reasonably approximated the actual deformation behavior for tests where multiple shear surfaces developed in close proximity to each other. For approximately half the tests, however, the single surface assumption proved to be an oversimplification. Accuracy was improved when the Newmark (1965) procedure was modified by using the acceleration-time history recorded in the soil immediately

  20. Posterior colporrhaphy does not affect the urethral closure mechanism

    DEFF Research Database (Denmark)

    Khayyami, Yasmine; Lose, Gunnar; Klarskov, Niels

    2018-01-01

    INTRODUCTION AND HYPOTHESIS: Studies have suggested that a posterior vaginal wall prolapse might compress the urethra and mask stress urinary incontinence (SUI), much like an anterior vaginal wall prolapse. A recent study with urethral pressure reflectometry (UPR) has shown that the urethral...... closure mechanism deteriorates after anterior colporrhaphy; this could explain the occurrence of postoperative de novo SUI. We hypothesized that urethral pressure would also decrease after posterior colporrhaphy. METHODS: This was a prospective, observational study where women with posterior vaginal wall...... significant. RESULTS: Eighteen women with posterior vaginal wall prolapse ≥stage II were recruited. One woman did not undergo surgery. There were no changes in urethral pressure at rest (p = 0.4), during squeezing (p = 0.2) or straining (p = 0.2), before and after surgery. The results of the stress tests...

  1. Outcomes of Surgery for Posterior Polar Cataract Using Torsional Ultrasound

    Directory of Open Access Journals (Sweden)

    Selçuk Sızmaz

    2013-10-01

    Full Text Available Purpose: The aim of this study is to report outcomes of surgery for posterior polar cataract using torsional ultrasound. Material and Method: Medical records of 26 eyes of 21 consecutive patients with posterior polar cataract who had cataract surgery using the torsional phacoemulsification were evaluated retrospectively. The surgical procedure used, phacoemulsification parameters, intraoperative complications, and postoperative visual outcome were recorded. Results: Of the 26 eyes, 24 (92.3% had small to medium posterior polar opacity. Two eyes had large opacity. All surgeries were performed using the torsional handpiece. Posterior capsule rupture occurred in 4 (15.3% eyes. The mean visual acuity improved significantly after surgery (p<0.001. The postoperative visual acuity was worse than 20/20 in 5 eyes. The cause of the low acuity was amblyopia. Discussion: Successful surgical results and good visual outcome can be achieved with phacoemulsification using the torsional handpiece. (Turk J Ophthalmol 2013; 43: 345-7

  2. Current management of posterior wall fractures of the acetabulum.

    Science.gov (United States)

    Moed, Berton R; Kregor, Philip J; Reilly, Mark C; Stover, Michael D; Vrahas, Mark S

    2015-01-01

    The general goals for treating an acetabular fracture are to restore congruity and stability of the hip joint. These goals are no different from those for the subset of fractures of the posterior wall. Nevertheless, posterior wall fractures present unique problems compared with other types of acetabular fractures. Successful treatment of these fractures depends on a multitude of factors. The physician must understand their distinctive radiologic features, in conjunction with patient factors, to determine the appropriate treatment. By knowing the important points of posterior surgical approaches to the hip, particularly the posterior wall, specific techniques can be used for fracture reduction and fixation in these often challenging fractures. In addition, it is important to develop a complete grasp of potential complications and their treatment. The evaluation and treatment protocols initially developed by Letournel and Judet continue to be important; however, the surgeon also should be aware of new information published and presented in the past decade.

  3. Nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability.

    Science.gov (United States)

    Wu, Tian-Long; Jia, Jing-Yu; Chen, Wei-Cai; He, Ding-Wen; Cheng, Xi-Gao

    2015-05-01

    Nontraumatic posterior atlantooccipital dislocation has only been rarely reported. In the current study, the authors reported an extremely rare case of nontraumatic posterior atlantooccipital dislocation associated with atlantoaxial instability. A 47-year-old female was referred with a history of neck pain for 5 years. The patient had no history of trauma. The axial rotation of range of motion of the cervical spine was severely restricted. Posterior atlantooccipital dislocation with atlantoaxial instability was confirmed through conventional radiography, computed tomography and magnetic resonance imaging. We performed realignment of the dislocation and posterior occipitocervical (C0-C2) fusion. After the surgery, the patient's symptoms improved significantly and she manifested neurological improvement. To our knowledge, this lesion has not been reported previously. Anomalies of upper cervical spine may have induced this instability.

  4. Increased Medial Meniscal Slope Is Associated With Greater Risk of Ramp Lesion in Noncontact Anterior Cruciate Ligament Injury.

    Science.gov (United States)

    Song, Guan-Yang; Liu, Xin; Zhang, Hui; Wang, Qian-Qian; Zhang, Jin; Li, Yue; Feng, Hua

    2016-08-01

    A special type of meniscal lesion involving the peripheral attachment of the posterior horn of the medial meniscus (PHMM), termed ramp lesion, is commonly associated with anterior cruciate ligament (ACL) injury. However, no study has investigated its anatomic risk factors. Recently, increased meniscal slope has been identified as an independent anatomic risk factor for noncontact ACL injury. Increased medial meniscal slope (MMS) as measured on magnetic resonance imaging (MRI) will correlate with greater risk of concomitant ramp lesion in noncontact ACL injury. Case-control study; Level of evidence, 3. From January 2011 to December 2013, a total of 1012 consecutive patients were diagnosed as having noncontact ACL injuries and underwent primary ACL reconstructions. Among them, 160 patients were arthroscopically verified to have concomitant ramp lesions. Study exclusion criteria included partial ACL rupture, multiligamentous injury, associated medial/lateral meniscal lesions other than ramp lesion, skeletal immaturity, general joint laxity, severe malalignment of the lower extremity, history of knee surgery, lack of available preoperative MRI, and history of trauma to the proximal tibia. This left 53 patients in the study group (ACL + ramp group), who were matched in a 1:1 fashion to 53 control participants (isolated ACL group) who were arthroscopically verified to have isolated complete ACL injury during the same study period. Patients were matched by age, sex, and time from injury to surgery (TFI). Patients from the matched control group were selected by applying the same exclusion criteria as mentioned above. The MMS and medial posterior tibial slope (MPTS) were measured on the preoperative MRI in a blinded fashion. Predictors of ramp lesion, including MMS, MPTS, body mass index, pivot-shift test grade, and KT-1000 arthrometer side-to-side difference, were assessed by multivariable conditional logistic regression analysis. The mean MMS in the study group was 3.5

  5. CT of adult lumbar disc herniations mimicking posterior apophyseal ring fractures

    Energy Technology Data Exchange (ETDEWEB)

    Gomori, J.M. (Hadassah Univ. Hospital, Jerusalem (Israel). Dept. of Radiology); Floman, Y.; Liebergall, M. (Hadassah Univ. Hospital, Jerusalem (Israel). Dept. of Orthopedics)

    1991-10-01

    This report concerns 35 adult patients with lumbar or sciatic pain and axial CT findings reportedly associated with posterior apophyseal ring fractures. Review of the CT images suggested two pathophysiologic categories. (1) Posterior Schmorl - A posterior intravertebral disc herniation with posterior displacement of a fractured or remodelled vertebral margin. (2) Calcified subligamentous - Reactive annular and or posterior longitudinal ligament calcification at the periphery of a herniated disc with or without remodelling and anterior displacement of the posterior vertebral margin. (orig.).

  6. Podoplanin and the posterior heart field: epicardial-myocardial interaction

    OpenAIRE

    Mahtab, Edris Ahmad Faiz

    2008-01-01

    This thesis introduces the posterior heart field contributing to the venous pole of the heart by epithelial-mesenchymal-transformation of the coelomic epithelium. Based on studying of podoplanin and Sp3 (novel genes in cardiogenesis) wildtype and knockout mouse embryos between stages 9.5-18.5, we postulate that the posterior heart field contributes through mesenchymal and myocardial cell populations. The mesenchymal population is involved in the formation of the proepicardial organ, epicardiu...

  7. The relationship between breastfeeding duration and posterior crossbite

    OpenAIRE

    Akinci Cansunar, Hatice; Alcin, Rukiye; Malkoc, Sıddık

    2016-01-01

    Posterior cross-bites is a common orthodontic malocclusion that occur as a result of a narrow maxilla and originate from genetic or environmental influences. Breastfeeding ensure that correct oral function is established and development of perioral muscle. In this way, breastfeeding has a preventive effect of the development of malocclusion. The aim of this study is to determine relationship between breastfeeding duration and prevalence of unilateral and bilateral posterior crossbite. Breastf...

  8. Rare association of female pseudohermaphroditism, phallic urethra, and posterior cloaca.

    Science.gov (United States)

    Macarthur, Mairi; Mahomed, Anies

    2006-03-01

    We describe a child with the rare clinical entity of female pseudohermaphroditism, accessory phallic urethra, and posterior cloaca who was successfully treated with posterior sagittal anorectovaginourethroplasty. Masculinization was limited to the external genitalia, and no chromosomal, metabolic, or adrenal abnormalities were detected. Associated pathology included bilateral vesicoureteric reflux, a non functioning dysplastic kidney, and bicornuate uterus. The investigation and surgical management of this particularly challenging combination of anomalies is detailed.

  9. A case report of inverted papilloma of the posterior urethra

    OpenAIRE

    長谷川, 総一郎; 絹川, 常郎; 松浦, 治; 竹内, 宜久; 服部, 良平; 小野, 佳成; 大島, 伸一; 村上, 榮

    1987-01-01

    Sixty-seven cases of inverted papilloma have been reported in many anatomical sites of urinary tract but only 9 cases involving the posterior urethra have been described in Japan. We report the 10th case of inverted papilloma of the posterior urethra in a 27-year-old male who complained of macroscopic hematuria. The lesion was diagnosed cystoscopically and treated by transurethral resection.

  10. Patient adaptable cerebellar retractor system: Use in posterior fossa surgery

    Directory of Open Access Journals (Sweden)

    Hamid Borghei-Razavi

    2015-06-01

    Full Text Available A new patient adaptable dual use soft tissue spreader and cerebellar retractor system designed for use during surgery of the posterior fossa is described. We found that this new retractor design allowed for excellent exposure, plus greater freedom and dexterity during the posterior fossa surgery. This novel instrument is an improvement over the existing instrument, because it provided more force/power transmission from pins/connectors to the brain spatula via the shorter flexible arm.

  11. Brainstem variant of posterior reversible encephalopathy syndrome: A case report.

    Science.gov (United States)

    Tortora, Fabio; Caranci, Ferdinando; Belfiore, Maria Paola; Manzi, Francesca; Pagliano, Pasquale; Cirillo, Sossio

    2015-12-01

    Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological condition, generally observed in conjunction with severe and acute hypertension, that involves mainly the posterior head areas (occipital and temporal lobes) and anterior "watershed" areas. In this syndrome it is rare to observe a predominant involvement of the brainstem. We describe the clinical and radiological findings in a patient with brainstem involvement, discussing its pathophysiological features and possible differential diagnosis. © The Author(s) 2015.

  12. Posterior partially edentulous jaws, planning a rehabilitation with dental implants

    Science.gov (United States)

    Monteiro, Douglas R; Silva, Emily V F; Pellizzer, Eduardo P; Filho, Osvaldo Magro; Goiato, Marcelo C

    2015-01-01

    AIM: To discuss important characteristics of the use of dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE (PubMed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations (bone quantity and density), radiographic techniques, implant selection (number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning. PMID:25610852

  13. Congenital Posterior Urethral Fistulae: Literature Review and Case Report.

    Science.gov (United States)

    Perez, Jaime F; Díaz B, Ana María; Ramos, Gustavo U; Peralta, Sara R

    2018-03-06

    Congenital posterior urethral-perineal fistula is an abnormal communication extending from the posterior urethra to the perineal skin. We present the case of an 11-year-old boy who had recurrent febrile urinary tract infections and abnormal dribbling of urine from the perineum. Fistulogram showed a paraescrotal fistula tract, which was then surgically excised. During the 10 months of follow-up, the patient remained asymptomatic without recurrence of urinary pathology. © 2018 S. Karger AG, Basel.

  14. Recurrent Massive Epistaxis from an Anomalous Posterior Ethmoid Artery

    OpenAIRE

    Greco, Marco Giuseppe; Mattioli, Francesco; Alberici, Maria Paola; Presutti, Livio

    2016-01-01

    A 50-year-old man, with no previous history of epistaxis, was hospitalized at our facility for left recurrent posterior epistaxis. The patient underwent surgical treatment three times and only the operator’s experience and radiological support (cranial angiography) allowed us to control the epistaxis and stop the bleeding. The difficult bleeding management and control was attributed to an abnormal course of the left posterior ethmoidal artery. When bleeding seems to come from the roof of the ...

  15. Posterior Lattice Degeneration Characterized by Spectral Domain Optical Tomography

    OpenAIRE

    Manjunath, Varsha; Taha, Mohammed; Fujimoto, James G.; Duker, Jay S.

    2011-01-01

    PURPOSE: To utilize high-resolution spectral domain optical coherence tomography (SD-OCT) in the characterization of retinal and vitreal morphological changes overlying posterior lattice degeneration. METHODS: A cross-sectional, retrospective analysis was performed on 13 eyes of 13 nonconsecutive subjects with posterior lattice degeneration seen at the New England Eye Center, Tufts Medical Center between October 2009 and January 2010. SD-OCT images taken through the region of latti...

  16. Ligamentous and capsular restraints to experimental posterior elbow joint dislocation

    DEFF Research Database (Denmark)

    Deutch, S.R.; Olsen, B.S.; Jensen, S.L.

    2003-01-01

    the anterior capsule and the lateral collateral ligament complex (LCLC), whereas in the flexed elbow the anterior capsule did not have a stabilizing effect. In flexed joint positions, the LCLC seems to be the only immediate stabilizer against PEFR, and thereby against posterolateral instability and possibly...... against posterior dislocation. The medial collateral ligament did not have any immediate stabilizing effect, but it prevented the final step of the posterior dislocation....

  17. Immediate Loading of Short Implants in Posterior Maxillae: Case Series

    OpenAIRE

    Anitua, Eduardo

    2017-01-01

    Background There is an increasing number of scientific evidence supporting the clinical use of short dental implants. However, few studies have evaluated the long-term outcomes of immediate loading protocols in short implants. This study aims to evaluate immediate loading of short dental implants in the posterior regions of the maxillae. Materials and methods Patients having short implants in maxillae posterior areas inserted before December, 2010 and immediately loaded were selected. The fol...

  18. Parascapular mass revealing primary tuberculosis of the posterior arch

    Science.gov (United States)

    Arbault, Anais; Ornetti, Paul; Chevallier, Olivier; Avril, Julien; Pottecher, Pierre

    2016-01-01

    We report the case of a parascapular abscess revealing primary tuberculosis of the posterior arch in a 31-year-old man. Sectional imaging is essential in order to detect the different lesions of this atypical spinal tuberculosis as osteolysis of the posterior arch extendible to vertebral body, osteocondensation, epidural extension which is common in this location, and high specificity of a zygapophysial, costo-vertebral or transverse arthritis. PMID:27709081

  19. Efficient Exploration of Multi-Modal Posterior Distributions

    OpenAIRE

    Hu, Yi-Ming; Hendry, Martin; Heng, Ik Siong

    2014-01-01

    The Markov Chain Monte Carlo (MCMC) algorithm is a widely recognised as an efficient method for sampling a specified posterior distribution. However, when the posterior is multi-modal, conventional MCMC algorithms either tend to become stuck in one local mode, become non-Markovian or require an excessively long time to explore the global properties of the distribution. We propose a novel variant of MCMC, mixed MCMC, which exploits a specially designed proposal density to allow the generation ...

  20. Materials Science Problems of the SCRF Q-Slope

    Science.gov (United States)

    Insepov, Z.; Norem, J.; Swenson, D. R.; Hassanein, A.

    2006-11-01

    None of the existing theoretical models can explain all the observed features of the Q-slope. In the present work, we review this problem and show how Atom Probe Tomography and Gas Cluster Ion Beam smoothing can study the basic mechanisms that may be involved. The gas cluster ion beam (GCIB) treatment method has recently been proposed as a new way to significantly reduce the surface roughness and the dark current from the rf-cavity surfaces. In addition to the suppression of the dark current, GCIB might also be an important treatment for mitigation of the Q-slope in superconducting cavities. Niobium surface treatment by cluster ion irradiation was studied based on atomistic and mesoscopic simulation methods and the surface modification dynamics results were compared to experiments.

  1. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    International Nuclear Information System (INIS)

    Yuan, Sheng; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; Church, Matthew; McKinney, Wayne R.; Morrison, Greg; Warwick, Tony

    2010-01-01

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situ visible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  2. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    International Nuclear Information System (INIS)

    Yuan, S.; Yashchuk, V.V.; Goldberg, K.A.; Celestre, R.; Church, M.; McKinney, W.R.; Morrison, G.; Warwick, T.

    2009-01-01

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situvisible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  3. Integration of Indoor Ski Slopes into the Urban Recreation System

    Directory of Open Access Journals (Sweden)

    Inga Urbonaitė

    2011-03-01

    Full Text Available Indoor ski slope is an innovative type of active indoor recreation. This new urban character is simulating the concept of mountain ski resort and is considered to be a strong attraction point all year-round. Due to a big scale and complexity, sustainable integration into an urban context should be very carefully considered. Economical, social, environmental and aesthetic impact on surrounding territories is an important factor to be evaluated. International practice shows that the appropriate integration of the above mentioned typology into urban parks increase their popularity and use of the recreation zone. On the other hand, the alien architecture and egocentric dominance of complexes can cause conflict with the existing urban territories and natural environment. Having indoor ski slopes in mind at the stages of regional and town territorial planning is an important point. Only complex development can bring positive results for sustainable town development, town economy, tourism and social life. Article in Lithuanian

  4. Optimal velocity in the race over variable slope trace.

    Science.gov (United States)

    Maroński, Ryszard; Samoraj, Piotr

    2015-01-01

    The minimum-time running problem is reconsidered. The time of covering a given distance is minimized. The function that should be found is the runner's velocity that varies with the distance. The Hill-Keller model of motion is employed. It is based on the Newton second law and an equation of power balance. The new element of the current approach is that the trace slope angle varies with the distance. The problem is formulated and solved in optimal control applying the Chebyshev direct pseudospectral method. The essential finding is that the optimal velocity during the cruise is constant regardless of the local slope of the terrain. Such result is valid if the inequality constraints imposed on the propulsive force or the energy are not active.

  5. Desirable plant root traits for protecting unstable slopes against landslides

    Science.gov (United States)

    Stokes, A.; Atger, C.; Bengough, G.; Fourcaud, T.; Sidle, R. C.

    2009-04-01

    A trait is defined as a distinct, quantitative property of organisms, usually measured at the individual level and used comparatively across species. Plant quantitative traits are extremely important for understanding the local ecology of any site. Plant height, architecture, root depth, wood density, leaf size and leaf nitrogen concentration control ecosystem processes and define habitat for other taxa. An engineer conjecturing as to how plant traits may directly influence physical processes occurring on sloping land just needs to consider how e.g. canopy architecture and litter properties influence the partitioning of rainfall among interception loss, infiltration and runoff. Plant traits not only influence abiotic processes occurring at a site, but also the habitat for animals and invertebrates. Depending on the goal of the landslide engineer, the immediate and long-term effects of plant traits in an environment must be considered if a site is to remain viable and ecologically successful. When vegetation is considered in models of slope stability, usually the only root parameters taken into consideration are tensile strength and root area ratio. Root system spatial structure is not considered, although the length, orientation and diameter of roots are recognized as being of importance. Thick roots act like soil nails on slopes, reinforcing soil in the same way that concrete is reinforced with steel rods. The spatial position of these thick roots also has an indirect effect on soil fixation in that the location of thin and fine roots will depend on the arrangement of thick roots. Thin and fine roots act in tension during failure on slopes and if they cross the slip surface, are largely responsible for reinforcing soil on slopes. Therefore, the most important trait to consider initially is rooting depth. To stabilize a slope against a shallow landslide, roots must cross the shear surface. The number and thickness of roots in this zone will therefore largely

  6. Posterior atlantoaxial fixation: a review of all techniques.

    Science.gov (United States)

    Huang, Da-Geng; Hao, Ding-Jun; He, Bao-Rong; Wu, Qi-Ning; Liu, Tuan-Jiang; Wang, Xiao-Dong; Guo, Hua; Fang, Xiang-Yi

    2015-10-01

    Posterior atlantoaxial fixation is an effective treatment for atlantoaxial instability. Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. However, there is no article reviewing all the posterior atlantoaxial fixation techniques yet. The aim was to review the evolution and advancements of posterior atlantoaxial fixation. This was a literature review. The application of all posterior fixation techniques in atlantoaxial stabilization, including wiring techniques, interlaminar clamp fixation, transarticular fixation, screw-plate systems, screw-rod systems, and hook-screw systems, are reviewed and discussed. Recent advancements on the novel technique of atlantoaxial fixation are described. The combination of the C1 and C2 screws in screw-rod systems are described in detail. All fixation techniques are useful. The screw-rod system appears to be the most popular approach. However, many novel or modified fixation methods have been introduced in recent years. Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. The wiring technique and interlaminar clamps technique have fallen out of favor because of the development of newer and superior fixation techniques. The C1-C2 transarticular screw technique may remain the gold standard for atlantoaxial fusion, whereas screw-rod systems, especially the C1 pedicle screw combined with C2 pedicle/pars screw fixation, have become the most popular fixation techniques. Hook-screw systems are alternatives for atlantoaxial fixation. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Surgical revascularization of posterior coronary arteries without cardiopulomonary bypass

    Directory of Open Access Journals (Sweden)

    Lobo Filho J. Glauco

    1999-01-01

    Full Text Available OBJECTIVE: To assess the results observed during the early postoperative period in patients who had the posterior coronary arteries revascularized without cardiopulmonary bypass (CPB, in regard to the following parameters: age, sex,bypass grafts types, morbidity and mortality. METHODS: From January 1995 to June 1998, 673 patients underwent myocardial revascularization (MR. Of this total, 607 (90.20% MR procedures were performed without CPB. The posterior coronary arteries (PCA were revascularized in 298 (44.27% patients, 280 (93.95% without CPB. The age of the patients ranged from 37 to 88 years (mean, 61 years. The male gender predominated, with 198 men (70.7%. The revascularization of the posterior coronary arteries had the following distribution: diagonalis artery (31 patients, 10%; marginal branches of the circumflex artery (243 patients, 78.7%; posterior ventricular artery (4 patients, 1.3%; and posterior descending artery (31 patients, 10%. RESULTS: Procedure-related complications without death occurred in 7 cases, giving a morbidity of 2.5%. There were 11 deaths in the early postoperative period (mortality of 3.9%. CONCLUSION: Similarly to the anterior coronary arteries, the posterior coronary arteries may benefit from myocardial revascularization without CPB.

  8. Conservation laws for shallow water waves on a sloping beach

    OpenAIRE

    Akyildiz, Yilmaz

    1986-01-01

    Shallow water waves are governed by a pair of non-linear partial differential equations. We transfer the associated homogeneous and non-homogeneous systems, (corresponding to constant and sloping depth, respectively), to the hodograph plane where we find all the non-simple wave solutions and construct infinitely many polynomial conservation laws. We also establish correspondence between conservation laws and hodograph solutions as well as Bäcklund transformations by using the linear nature of...

  9. Center Line Slope Analysis in Two-Dimensional Electronic Spectroscopy

    OpenAIRE

    ?anda, Franti?ek; Perl?k, V?clav; Lincoln, Craig N.; Hauer, J?rgen

    2015-01-01

    Center line slope (CLS) analysis in 2D infrared spectroscopy has been extensively used to extract frequency?frequency correlation functions of vibrational transitions. We apply this concept to 2D electronic spectroscopy, where CLS is a measure of electronic gap fluctuations. The two domains, infrared and electronic, possess differences: In the infrared, the frequency fluctuations are classical, often slow and Gaussian. In contrast, electronic spectra are subject to fast spectral diffusion and...

  10. Evaluation of Thermoelectric Devices by the Slope-Efficiency Method

    Science.gov (United States)

    2016-09-01

    materials: the Seebeck coefficient, α; the electrical resistivity , ρ; and the thermal conductivity, κ. However, experimental measurement of those...Rload, then total system resistance is equal to 2Rint and open- circuit voltage, Voc, drops by half leading to Approved for public release...Evaluation of Thermoelectric Devices by the Slope-Efficiency Method by Patrick J Taylor Sensors and Electron Devices Directorate, ARL Jay R

  11. [Current incidence of accidents on Austrian ski slopes].

    Science.gov (United States)

    Ruedl, G; Philippe, M; Sommersacher, R; Dünnwald, T; Kopp, M; Burtscher, M

    2014-12-01

    Alpine skiing and snowboarding are the most popular winter sports. These sports are also associated with a certain injury risk which, however, has steadily decreased during the past decades. During the winter season 2002/2003 the last large survey on ski injuries in Austria was performed. Among others, modern skiing equipment and optimized slope preparation may impact on the injury risk. We hypothesise that these changes may have led to a further decrease in ski injuries during the past decade. In the winter season 2012/2013, skiing injuries were recorded in 26 Austrian ski areas. Data were collected from rescue personnel on ski slopes and by physicians in the hospital or doctors practice with the help of a questionnaire. A total of 7325 injured skiers and snowboarders (age: 34.8 ± 17.8 years) were recorded (49 % males and 51 % females; 80 % skiers, 14 % snowboarders, 6 % others). The most frequent causes of injury were self-inflicted falls (87 %) and collisions with other skiers/snowboarders (8 %). Most affected injury locations among skiers were the knee (41 %; predominantly in female skiers, > 50 %), shoulder/back (18 %) and arms (10 %). Most affected injury locations among snowboarders were arms (38 %) and shoulder/back (23 %). Head injuries were found at the same frequency (8 %) in skiers and snowboarders. The calculated injury rate was about 0.6 injuries per 1000 skier days and has decreased by more than 50 % during the past decade. Modern skiing equipment and optimised slope preparation may be at least partly responsible for the decreased injury risk on ski slopes which is supported by the observation of a reduced falling frequency. Future preventive measures should focus on a reduction of knee injuries in female skiers. © Georg Thieme Verlag KG Stuttgart · New York.

  12. A generalization of the Ross-Thomas slope theory

    OpenAIRE

    Odaka, Yuji

    2013-01-01

    We give a formula for the Donaldson--Futaki invariants of certain type of semi test configurations, which essentially generalizes the Ross--Thomas slope theory [28]. The positivity (resp. non-negativity) of those ``a priori special'' Donaldson--Futaki invariants implies K-stability (resp. K-semistability). As an application, we prove the K-(semi)stability of certain polarized varieties with semi-log-canonical singularities, which generalizes some results of [28].

  13. A generalization of Ross-Thomas' slope theory

    OpenAIRE

    Odaka, Yuji

    2009-01-01

    We give a formula of the Donaldson-Futaki invariants for certain type of semi test configurations, which essentially generalizes Ross-Thomas' slope theory. The positivity (resp. non-negativity) of those "a priori special" Donaldson-Futaki invariants implies K-stability (resp. K-semistability). We show its applicability by proving K-(semi)stability of certain polarized varieties with semi-log-canonical singularities, generalizing some results by Ross-Thomas.

  14. Vector polynomials for direct analysis of circular wavefront slope data.

    Science.gov (United States)

    Mahajan, Virendra N; Acosta, Eva

    2017-10-01

    In the aberration analysis of a circular wavefront, Zernike circle polynomials are used to obtain its wave aberration coefficients. To obtain these coefficients from the wavefront slope data, we need vector functions that are orthogonal to the gradients of the Zernike polynomials, and are irrotational so as to propagate minimum uncorrelated random noise from the data to the coefficients. In this paper, we derive such vector functions, which happen to be polynomials.

  15. Proposal for a Universal Test Mirror for Characterization of Slope Measuring Instruments

    International Nuclear Information System (INIS)

    Yashchuk, Valeriy V.; McKinney, Wayne R.; Warwick, Tony; Noll, Tino; Siewert, Frank; Zeschke, Thomas; Geckeler, Ralf D.

    2007-01-01

    The development of third generation light sources like the Advanced Light Source (ALS) or BESSY II brought to a focus the need for high performance synchrotron optics with unprecedented tolerances for slope error and micro roughness. Proposed beam lines at Free Electron Lasers (FEL) require optical elements up to a length of one meter, characterized by a residual slope error in the range of 0.1mu rad (rms),and rms values of 0.1 nm for micro roughness. These optical elements must be inspected by highly accurate measuring instruments, providing a measurement uncertainty lower than the specified accuracy of the surface under test. It is essential that metrology devices in use at synchrotron laboratories be precisely characterized and calibrated to achieve this target. In this paper we discuss a proposal for a Universal Test Mirror (UTM) as a realization of a high performance calibration instrument. The instrument would provide an ideal calibration surface to replicate a redundant surface under test of redundant figure. The application of a sophisticated calibration instrument will allow the elimination of the majority of the systematic error from the error budget of an individual measurement of a particular optical element. We present the limitations of existing methods, initial UTM design considerations, possible calibration algorithms, and an estimation of the expected accuracy

  16. [One-segment interbody lumbar arthrodesis using impacted cages: posterior unilateral approach versus posterior bilateral approach].

    Science.gov (United States)

    Commarmond, J

    2001-04-01

    We assessed the relative advantages of unilateral versus bilateral posterior approaches for lumbar spine fusion. Eighty-three patients who underwent lumbar spine fusion via a bilateral posterior approach and who had reached more than two years follow-up were compared with 80 patients who had undergone the same procedure via a unilateral posterior approach, including 54 with a follow-up greater than one year and 24 greater than two years. Most cases were L4-L5 fusions for degenerative spondylolisthesis or recurrent discal herniation with instability. Two composite carbon cages were filled with autologous cancellous bone. The key to the unilateral approach was the comfortable exposure of the disc by lamino-arthectomy; the osteosynthesis could then be performed unilaterally if only one gutter was opened. We measured bleeding and operative time to quantify surgical difficulty. At one year we assessed disc height, lordosis, frontal balance, and fusion of the operated disk. At two years, we assessed lombalgia and sciatalgia [scored from 4 (none) to 0 (intolerable)], subjective outcome, and recovery of former activity level. Mean blood loss and operative time were 360 ml and 162 min for the 83 classical procedures and 216 ml and 118 min for the 80 unilateral procedures. There were ten dural wounds with the bilateral approach and one dural wound and one transient radicular deficit with the unilateral approach. At one year, 81 of the 83 unilateral cases had reached fusion (2 nonunions). There was a mean 2 degrees gain in discal lordosis despite three cases of impaction due to osteoporosis. For the unilateral procedures, all 54 reached fusion at one year with a mean 2.5 degrees gain in lordosis, also with 3 impactions. With intersomatic distraction, balanced disc height in the frontal plane was obtained in all cases where the initial narrowing was not excessive. There were no cases of posterior displacement. There was a degradation of the supra-adjacent segment in three of

  17. Review of the Frontier Workshop and Q-slope results

    Energy Technology Data Exchange (ETDEWEB)

    Gianluigi Ciovati

    2005-09-20

    Over the last few years, significant progress has been made to produce field emission free niobium surfaces. Nowadays, the major limitation towards achieving the critical field in radio-frequency (rf) superconducting cavities made of bulk niobium of high purity is represented by the so-called ''high field Q-slope'' or ''Q-drop''. This phenomenon is characterized by a sharp decrease of the cavity quality factor, in absence of field emission, starting at a peak surface magnetic field of the order of 100 mT. It has been observed that these losses are usually reduced by a low-temperature ''in-situ'' baking, typically at 100-120 C for 24-48 h. Several models have been proposed to explain the high field Q-slope and many experiments have been conducted in different laboratories to validate such models. A three-day workshop was held in Argonne in September 2004 to present and discuss experimental and theoretical results on the present limitations of superconducting rf cavities. In this paper, we will focus on the high field Q-slope by reviewing the results presented at the workshop along with other experimental data. In order to explain the Q-drop and the baking effect we will discuss an improved version of the oxygen diffusion model.

  18. Minimizing Slope and Kick of Intermediate Bunches for Electron Cooling

    Science.gov (United States)

    Dotson, Andrew

    2017-09-01

    Ions in the Jefferson Lab Electron-Ion Collider (JLEIC) will have transverse energy, which limits the beams density. Electron cooling is a process by which a beam of bunched electrons with small transverse kinetic energy is directed along the ion beam with the same velocity. The ions transfer their transverse kinetic energy to the electron bunches, making the ions lose transverse energy. Electron bunches will be supplied by an electron gun. The required current needed to cool the ion beam can be reached by reusing electrons and incorporating RF kicker cavities to supply a pulsed electric field that kicks every 11th bunch out of the cooling ring. This provides an exact solution that yields zero kick and slope to all intermediate bunches in the cooling ring, which is described by a cosine series with 11 terms. The goal of this project is to determine if solutions exist that are sufficiently close to zero kick and slope, but require less than 4 kicker cavities. The method used to find these solutions is minimizing an objective function through Sequential Least Squares Programming (SLSQP). A Pareto front then demonstrated the average kick vs. average slope when using 1 through 4 kickers.

  19. North Slope Decision Support for Water Resource Planning and Management

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, William; Brumbelow, Kelly

    2013-03-31

    The objective of this project was to enhance the water resource decision-making process with respect to oil and gas exploration/production activities on Alaska’s North Slope. To this end, a web-based software tool was developed to allow stakeholders to assemble, evaluate, and communicate relevant information between and amongst themselves. The software, termed North Slope Decision Support System (NSDSS), is a visually-referenced database that provides a platform for running complex natural system, planning, and optimization models. The NSDSS design was based upon community input garnered during a series of stakeholder workshops, and the end product software is freely available to all stakeholders via the project website. The tool now resides on servers hosted by the UAF Water and Environmental Research Center, and will remain accessible and free-of-charge for all interested stakeholders. The development of the tool fostered new advances in the area of data evaluation and decision support technologies, and the finished product is envisioned to enhance water resource planning activities on Alaska’s North Slope.

  20. A critical review of rock slope failure mechanisms: The importance of structural geology

    Science.gov (United States)

    Stead, Doug; Wolter, Andrea

    2015-05-01

    Geological structures such as folds, faults, and discontinuities play a critical role in the stability and behaviour of both natural and engineered rock slopes. Although engineering geologists have long recognised the importance of structural geology in slopes, it remains a significant challenge to integrate structural geological mapping and theory into all stages of engineering projects. We emphasise the importance of structural geology to slope stability assessments, reviewing how structures control slope failure mechanisms, how engineering geologists measure structures and include them in slope stability analyses, and how numerical simulations of slopes incorporate geological structures and processes.

  1. Posterior column reconstruction improves fusion rates at the level of osteotomy in three-column posterior-based osteotomies.

    Science.gov (United States)

    Lewis, Stephen J; Mohanty, Chandan; Gazendam, Aaron M; Kato, So; Keshen, Sam G; Lewis, Noah D; Magana, Sofia P; Perlmutter, David; Cape, Jennifer

    2018-03-01

    To determine the incidence of pseudarthrosis at the osteotomy site after three-column spinal osteotomies (3-COs) with posterior column reconstruction. 82 consecutive adult 3-COs (66 patients) with a minimum of 2-year follow-up were retrospectively reviewed. All cases underwent posterior 3-COs with two-rod constructs. The inferior facets of the proximal level were reduced to the superior facets of the distal level. If that was not possible, a structural piece of bone graft either from the local resection or a local rib was slotted in the posterior column defect to re-establish continual structural posterior bone across the lateral margins of the resection. No interbody cages were used at the level of the osteotomy. There were 34 thoracic osteotomies, 47 lumbar osteotomies and one sacral osteotomy with a mean follow-up of 52 (24-126) months. All cases underwent posterior column reconstructions described above and the addition of interbody support or additional posterior rods was not performed for fusion at the osteotomy level. Among them, 29 patients underwent one or more revision surgeries. There were three definite cases of pseudarthrosis at the osteotomy site (4%). Six revisions were also performed for pseudarthrosis at other levels. Restoration of the structural integrity of the posterior column in three-column posterior-based osteotomies was associated with > 95% fusion rate at the level of the osteotomy. Pseudarthrosis at other levels was the second most common reason for revision following adjacent segment disease in the long-term follow-up.

  2. Transconjunctival Blepharoptosis Surgery: A Review of Posterior Approach Ptosis Surgery and Posterior Approach White-Line Advancement

    OpenAIRE

    Patel, Vikesh; Malhotra, Raman

    2010-01-01

    Posterior approach blepharoptosis surgery, via the transconjunctival route, was probably the first method of surgery employed to shorten the levator palpebrae superioris (LPS) muscle. A review of the literature demonstrates how surgery has evolved since Blaskovics’ first described his technique in 1923. We describe our newer method of posterior approach white-line advancement blepharoptosis repair which is now an option in the majority of aponeurotic ptosis with moderate to good levator funct...

  3. Agricultural terraces and slope instability at Cinque Terre (NW Italy)

    Science.gov (United States)

    Brandolini, Pierluigi; Cevasco, Andrea

    2015-04-01

    Cinque Terre, located in the eastern Liguria, are one of the most representative examples of terraced coastal landscape within the Mediterranean region. They are the result of a century-old agricultural practice and constitute an outstanding example of human integration with the natural landscape. For this highly unusual man-made coastal landscape, the Cinque Terre have been recognized as a World Heritage Site by UNESCO since 1997 and became National Park in 1999. The complex network of retaining dry stone walls and drainage networks ensured through times the control of shallow water erosion and therefore, indirectly, favoured debris cover stability. The lack of maintenance of terracing due to farmer abandonment since the 1950s led to widespread slope erosion phenomena. The effects of such phenomena culminated during the 25 October 2011 storm rainfall event, when slope debris materials charged by streams gave rise to debris floods affecting both Monterosso and Vernazza villages. As the analysis of the relationships between geo-hydrological processes and land use in the Vernazza catchment highlighted, abandoned and not well maintained terraces were the most susceptible areas to shallow landsliding and erosion triggered by intense rainfall. As a consequence, the thousands of kilometres of dry stone walls retaining millions of cubic metres of debris cover at Cinque Terre currently constitute a potential menace for both villages, that are mainly located at the floor of deep cut valleys, and tourists. Given the increasing human pressure due to tourist activities, geo-hydrological risk mitigation measures are urgently needed. At the same time, restoration policies are necessary to preserve this extraordinary example of terraced coastal landscape. In this framework, the detailed knowledge of the response of terraced areas to intense rainfall in terms of slope instability is a topic issue in order to identify adequate land planning strategies as well as the areas where

  4. Large slope failures in the La Paz basin, Bolivian Andes

    Science.gov (United States)

    Roberts, N. J.; Hermanns, R. L.; Rabus, B.; Guzmán, M. A.; Minaya, E.; Clague, J. J.

    2014-12-01

    The La Paz basin in the eastern Bolivian Andes has been a hotspot for large-scale, deep-seated gravitational slope deformation during the Holocene. In less than 2 Ma, a network of steep-sided valleys up to 800 m deep formed in sediments of the Altiplano Plateau and underlying basement rocks. We characterize the distribution, extent, mechanisms, and modern activity of large-scale failures within this landscape using optical image interpretation, existing geologic maps, synthetic RADAR interferometry (InSAR), and field investigation. Deposits of nearly 20 landslides larger than 100 Mm3 occur within the basin. Most failures have occurred in weakly lithified Late Miocene to Pliocene sedimentary rocks and include earth flows, translational and rotational landslides, and plug flows. Failures in underlying tectonized Paleozoic sedimentary rocks include bedding-parallel rockslides. The largest failure is the 3 km3 Achcocalla earth flow (ca. 11 ka BP), which ran out ~20 km. Other dated events span the period from the early Holocene to nearly the Colonial historic period. InSAR results show that many large slope failures, including the Achocalla earth flow, are currently moving at rates of a few centimeters to a few decimeters per year. Rapid deposition, shallow burial, and rapid incision of the basin fills produced steep slopes in weak geologic materials that, coupled with groundwater discharge from the valley walls, are the primary controls on instability. In contrast, the Altiplano surface has changed little in 2 Ma and the adjacent slopes of the Cordilleran Real, although steep, are relatively stable. Of the over 100 landslides that have occurred in the city of La Paz since the early twentieth century, most are at the margins of large, deep-seated prehistoric failures, and two of the most damaging historic landslides (Hanko-Hanko, 1582; Pampahasi, 2011) were large-scale reactivations of previously failed slopes. Improved understanding of large, deep-seated landslides in

  5. GIS modelling of slope stability in Phewa Tal watershed, Nepal

    Science.gov (United States)

    Rowbotham, David N.; Dudycha, Douglas

    1998-12-01

    Hazards are an inherent but dangerous and costly element of mountainous environments. Conventional maps of mountain hazards provide useful inventories of hazardous sites but provide little insight into the operation of the hazards. Furthermore, this approach tends to rely heavily on subjective interpretation of the landscape, which means that the results can not be replicated or transferred to other areas. Thus, alternative approaches employing the quantitative capabilities of geographic information systems (GIS) to model and predict slope stability are receiving increasing attention. This paper reports on the use of a diverse GIS database, compiled primarily from existing maps and aerial photographs, to construct a regional model of slope stability in Phewa Tal watershed, Nepal. An integral part of the research was to explore an alternative approach to the commonly used grid cell approach by employing geomorphometrically significant terrain units. The terrain units employed were created by generating line networks representing local maxima and minima extracted from elevation and curvature surfaces. One of the chief benefits of applying GIS technology in this research was the ability to georeference all of the attribute data to these terrain units. In doing so, it allowed the database to be exported into an external statistical package, where the terrain units could be statistically explored as the basic analytical unit. The application of a variety of statistical techniques resulted in logistic regression being selected as the most useful. Logistic regression successfully predicted terrain units as being either stable or unstable at a rate of approximately 90% concordance with a conventionally produced map of slope stability. The statistical probabilities of terrain unit stability were imported back into the GIS to produce a map of predicted slope stability that compared well with the conventional map of slope stability. The findings of this research suggest that

  6. Preserving Posterior Complex Can Prevent Adjacent Segment Disease following Posterior Lumbar Interbody Fusion Surgeries: A Finite Element Analysis.

    Science.gov (United States)

    Huang, Yun-Peng; Du, Cheng-Fei; Cheng, Cheng-Kung; Zhong, Zheng-Cheng; Chen, Xuan-Wei; Wu, Gui; Li, Zhe-Cheng; Ye, Jin-Duo; Lin, Jian-Hua; Wang, Li Zhen

    2016-01-01

    To investigate the biomechanical effects of the lumbar posterior complex on the adjacent segments after posterior lumbar interbody fusion (PLIF) surgeries. A finite element model of the L1-S1 segment was modified to simulate PLIF with total laminectomy (PLIF-LAM) and PLIF with hemilaminectomy (PLIF-HEMI) procedures. The models were subjected to a 400N follower load with a 7.5-N.m moment of flexion, extension, torsion, and lateral bending. The range of motion (ROM), intradiscal pressure (IDP), and ligament force were compared. In Flexion, the ROM, IDP and ligament force of posterior longitudinal ligament, intertransverse ligament, and capsular ligament remarkably increased at the proximal adjacent segment in the PLIF-LAM model, and slightly increased in the PLIF-HEMI model. There was almost no difference for the ROM, IDP and ligament force at L5-S1 level between the two PLIF models although the ligament forces of ligamenta flava remarkably increased compared with the intact lumbar spine (INT) model. For the other loading conditions, these two models almost showed no difference in ROM, IDP and ligament force on the adjacent discs. Preserved posterior complex acts as the posterior tension band during PLIF surgery and results in less ROM, IDP and ligament forces on the proximal adjacent segment in flexion. Preserving the posterior complex during decompression can be effective on preventing adjacent segment degeneration (ASD) following PLIF surgeries.

  7. Influence of soil physical properties and vegetation coverage at different slope aspects in a reclaimed dump.

    Science.gov (United States)

    Pan, Jian; Bai, Zhongke; Cao, Yingui; Zhou, Wei; Wang, Jinman

    2017-10-01

    Vegetation coverage is an important parameter for affecting soil erosion and the physical and chemical properties of soil. To analyze the mutual influence between vegetation coverage and soil quality at different slope aspects in a reclaimed dump, fitting analyses were built between the normalized difference vegetation index and soil physical properties at each slope aspect. Twenty six quadrats were sampled in slope-platform alternate mode. Each quadrat was 10 m × 10 m. Vegetation index and soil physical properties were measured and calculated. Through curve fitting analysis, the results showed that soil bulk density has a negative correlation with the vegetation index on shady and half shady slopes, sunny slopes, and half sunny slopes. Soil porosity has a positive correlation with the vegetation index on shady and half shady slopes, sunny slope, and half sunny slope. The soil mass water content has a concave function relationship with the vegetation index on shady and half shady slopes and has a quadratic function relationship with the vegetation index on sunny and half sunny slopes, with the parabola moving upwards. The soil gravel content has a linear relationship with the vegetation index on shady and half shady slopes, and the image has a negative slope with a quadratic function relationship to the vegetation index on sunny slope and half sunny slope, with the parabola moving downwards. Due to differences among hydrothermal conditions, the relationship between vegetation coverage and soil quality indicators at different slope aspects is different; therefore, reasonable improvement of soil quality indicators on sunny and half sunny slopes could help plants to grow. These findings feed into a reference document that sets out how vegetation and soil quality may be improved in mining areas.

  8. The influence of slope on Spartium junceum root system: morphological, anatomical and biomechanical adaptation.

    Science.gov (United States)

    Lombardi, Fabio; Scippa, G S; Lasserre, B; Montagnoli, A; Tognetti, R; Marchetti, M; Chiatante, D

    2017-05-01

    Root systems have a pivotal role in plant anchorage and their mechanical interactions with the soil may contribute to soil reinforcement and stabilization of slide-prone slopes. In order to understand the responses of root system to mechanical stress induced by slope, samples of Spartium junceum L., growing in slope and in plane natural conditions, were compared in their morphology, biomechanical properties and anatomical features. Soils sampled in slope and plane revealed similar characteristics, with the exception of organic matter content and penetrometer resistance, both higher in slope. Slope significantly influenced root morphology and in particular the distribution of lateral roots along the soil depth. Indeed, first-order lateral roots of plants growing on slope condition showed an asymmetric distribution between up- and down-slope. Contrarily, this asymmetric distribution was not observed in plants growing in plane. The tensile strength was higher in lateral roots growing up-slope and in plane conditions than in those growing down-slope. Anatomical investigations revealed that, while roots grown up-slope had higher area covered by xylem fibers, the ratio of xylem and phloem fibers to root diameter did not differ among the three conditions, as also, no differences were found for xylem fiber cell wall thickness. Roots growing up-slope were the main contributors to anchorage properties, which included higher strength and higher number of fibers in the xylematic tissues. Results suggested that a combination of root-specific morphological, anatomical and biomechanical traits, determines anchorage functions in slope conditions.

  9. Performance of the Bowen ratio systems on a 22 deg slope

    Science.gov (United States)

    Nie, D.; Flitcroft, I.; Kanemasu, E. T.

    1990-01-01

    The Bowen ratio energy balance technique was used to assess the energy fluxes on inclined surfaces during the First ISLSCP Field Experiment (FIFE). Since air flow over sloping surface may differ from that over flat terrain, it is important to examine whether Bowen ratio measurements taken on sloping surfaces are valid. In this study, the suitability of using the Bowen ratio technique on sloping surfaces was tested by examining the assumptions that the technique requires for valid measurements. This was accomplished by studying the variation of Bowen ratio measurements along a selected slope at the FIFE site. In September 1988, four Bowen ratio systems were set up in a line along the 22 degree north-facing slope with northerly air flow (wind went up the slope). In July of 1989, six Bowen ratio systems were similarly installed with southerly air flow (the wind went down slope). Results indicated that, at distances between 10 to 40 meters from the top of the slope, no temperature or vapor pressure gradient parallel to the slope was detected. Uniform Bowen ratio values were obtained on the slope, and thus the sensible or latent heat flux should be similar along the slope. This indicates that the assumptions for valid flux measurements are reasonably met at the slope. The Bowen ratio technique should give the best estimates of the energy fluxes on slopes similar to that in this study.

  10. Kyphoplasty for osteoporotic vertebral fractures with posterior wall injury.

    Science.gov (United States)

    Abdelgawaad, Ahmed Shawky; Ezzati, Ali; Govindasamy, Ramachandran; Krajnovic, Branko; Elnady, Belal; Said, Galal Zaki

    2017-11-14

    Cement augmentation techniques are standard treatments for osteoporotic vertebral fractures. Compared with vertebroplasty, kyphoplasty is associated with lower rates of cement leak and better deformity correction; however, posterior wall fractures are relative, but not absolute; contraindications for both techniques and hence treatment practices vary among spine centers. The primary aim of this study was to assess our center's incidence of posterior cement leakage in osteoporotic vertebral fractures with posterior wall injury treated by balloon kyphoplasty (BKP). Secondarily, physiological results, pain relief, complication rates, and non-posterior cement leakage were also evaluated. This is a prospective cohort study done in a high-volume spine center in Germany. Eighty-two patients with 98 osteoporotic vertebral fractures with posterior wall cortical injury were studied from 2012 to 2016. The following were the outcome measures: (1) physiological measures: standing plain x-rays (anteroposterior and lateral views), with the following parameters evaluated: cement leak behind the posterior vertebral body border, Cobb angle for local sagittal deformity, vertebral wedge angle, and anterior vertebral height; (2) cement volume injected in each vertebra; and (3) self-report measures: visual analog scale (VAS). All patients underwent BKP using a bipedicular approach. Preoperative clinical and neurologic evaluations were done. Radiological evaluations included plain x-rays, computed tomography scans and magnetic resonance imaging. The average follow-up period was 18 months. No cement leakage into the spinal canal occurred in any of the patients. Asymptomatic leakage into other sites was seen in 22 vertebrae (22.45%). There was significant improvement in the Cobb angle, the vertebral wedge angle, and the anterior vertebral height in all cases. The mean preoperative VAS was 8.1, and this improved to 2.3 on the third postoperative day. Balloon kyphoplasty is a viable option

  11. Posterior transodontoid fixation: A new fixation (Kotil technique

    Directory of Open Access Journals (Sweden)

    Kadir Kotil

    2011-01-01

    Full Text Available Anterior odontoid screw fixation or posterior C1-2 fusion techniques are routinely used in the treatment of Type II odontoid fractures, but these techniques may be inadequate in some types of odontoid fractures. In this new technique (Kotil technique, through a posterior bilateral approach, transarticular screw fixation was performed at the non-dominant vertebral artery (VA side and posterior transodontoid fixation technique was performed at the dominant VA side. C1-2 complex fusion was aimed with unilateral transarticular fixation and odontoid fixation with posterior transodontoid screw fixation. Cervical spinal computed tomography (CT of a 40-year-old male patient involved in a motor vehicle accident revealed an anteriorly dislocated Type II oblique dens fracture, not reducible by closed traction. Before the operation, the patient was found to have a dominant right VA with Doppler ultrasound. He was operated through a posterior approach. At first, transarticular screw fixation was performed at the non-dominant (left side, and then fixation of the odontoid fracture was achieved by directing the contralateral screw (supplemental screw medially and toward the apex. Cancellous autograft was scattered for fusion without the need for structural bone graft or wiring. Postoperative cervical spinal CT of the patient revealed that stabilization was maintained with transarticular screw fixation and reduction and fixation of the odontoid process was achieved completely by posterior transodontoid screw fixation. The patient is at the sixth month of follow-up and complete fusion has developed. With this new surgical technique, C1-2 fusion is maintained with transarticular screw fixation and odontoid process is fixed by concomitant contralateral posterior transodontoid screw (supplemental screw fixation; thus, this technique both stabilizes the C1-2 complex and fixes the odontoid process and the corpus in atypical odontoid fractures, appearing as an

  12. Intensity modulated radiation-therapy for preoperative posterior abdominal wall irradiation of retroperitoneal liposarcomas

    International Nuclear Information System (INIS)

    Bossi, Alberto; De Wever, Ivo; Van Limbergen, Erik; Vanstraelen, Bianca

    2007-01-01

    Purpose: Preoperative external-beam radiation therapy (preop RT) in the management of Retroperitoneal Liposarcomas (RPLS) typically involves the delivery of radiation to the entire tumor mass: yet this may not be necessary. The purpose of this study is to evaluate a new strategy of preop RT for RPLS in which the target volume is limited to the contact area between the tumoral mass and the posterior abdominal wall. Methods and Materials: Between June 2000 and Jan 2005, 18 patients with the diagnosis of RPLS have been treated following a pilot protocol of pre-op RT, 50 Gy in 25 fractions of 2 Gy/day. The Clinical Target Volume (CTV) has been limited to the posterior abdominal wall, region at higher risk for local relapse. A Three-Dimensional conformal (3D-CRT) and an Intensity Modulated (IMRT) plan were generated and compared; toxicity was reported following the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events v3.0. Results: All patients completed the planned treatment and the acute toxicity was tolerable: 2 patients experienced Grade 3 and 1 Grade 2 anorexia while 2 patients developed Grade 2 nausea. IMRT allows a better sparing of the ipsilateral and the contralateral kidney. All tumors were successfully resected without major complications. At a median follow-up of 27 months 2 patients developed a local relapse and 1 lung metastasis. Conclusions: Our strategy of preop RT is feasible and well tolerated: the rate of resectability is not compromised by limiting the preop CTV to the posterior abdominal wall and a better critical-structures sparing is obtained with IMRT

  13. Posterior Ischemic Optic Neuropathy Following Percutaneous Nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Mohammad Pakravan

    2008-12-01

    Full Text Available

    PURPOSE: To report a case of posterior ischemic optic neuropathy (PION following percutaneous nephrolithotomy (PCNL. CASE REPORT: A 57-year-old man with history of diabetes mellitus, hyperlipidemia and mild anemia underwent PCNL for treatment of nephrolithiasis. He noticed painless visual loss in both eyes immediately after the procedure. Visual acuity was light perception, however ophthalmologic examinations were unremarkable and the optic discs were pink with no swelling. Visual fields were severely affected, but neuro-imaging was normal. Within three months, visual acuity and visual fields improved dramatically but the optic discs became slightly pale. CONCLUSION: This is the first report of PION following PCNL. PION is a rare cause of severe visual loss following surgery. Severe blood loss, hypotension, anemia and body position during surgery are the most important risk factors. Ophthalmologists, urologists and anesthesiologists should be aware of this condition and this rare possibility should be considered prior to surgery.

  1. Posterior urethral valves: Morphological normalization of posterior urethra after fulguration is a significant factor in prognosis

    Directory of Open Access Journals (Sweden)

    Menon Prema

    2010-01-01

    Full Text Available Aim: To assess the changes in urethral morphology 3 months post fulguration of posterior urethral valves (PUVs on micturating cystourethrogram (MCUG and correlate these changes with the overall clinical status of the patient. Materials and Methods: A total of 217 children, managed for PUVs during a period of 6 years in a single surgical unit were prospectively studied. The ratio of the diameters of the prostatic and bulbar urethras (PU/BU was calculated on the pre- and post-fulguration MCUG films. They were categorized into three groups based on the degree of normalization of posterior urethra (post-fulguration PU/BU ratio. Results: Group A: Of the 133 patients, 131 had normal urinary stream and 4 (3% had nocturnal enuresis. Vesicoureteral reflux (VUR, initially seen in 83 units (31% units, regressed completely at a mean duration of 6 months in 41 units (49%. Of the 152 non-VUR, hydroureteronephrosis (HUN units, 11 were poorly functioning kidneys. Persistent slow but unobstructed drainage was seen in 23 units (16% over a period of 1.5-5 years (mean 2.5 years. Group B: All the 11 patients had a normal stream. Four (36.4% had daytime frequency for a mean duration of 1 year and one (9% had nocturnal enuresis for 1 year. Grade IV-V VUR was seen in five patients (three bilateral, which regressed completely by 3 months in five units (62.5%. In the non-VUR, HUN patients, slow (but unobstructed drainage was persistent in two units (14% at 3 years. Group C: Of the 16 patients, only 5 (31.3% were asymptomatic. Six patients (nine units had persistent VUR for 6 months to 3 years. Of the 20 units with HUN, 17 (85% were persistent at 1-4 years (mean 2 years. Eight patients (50% required a second fulguration while 3 (18.7% required urethral dilatation for stricture following which all parameters improved. Conclusions: Adequacy of fulguration should be assessed by a properly performed MCUG. A postop PU/BU ratio >3 SD (1.92 should alert to an incomplete

  2. Tibialis Posterior Tenosynovitis: A Unique Musculoskeletal Manifestation of Gout.

    Science.gov (United States)

    Shupper, Peter; Stitik, Todd P

    2018-02-01

    Extra-articular manifestations of gout can present in several ways, including tenosynovitis. We present a rare case of acute tibialis posterior gouty tenosynovitis. An 82-year-old man with a history of well-controlled gout presented with acute onset of left ankle pain, occurring without inciting event. The medial ankle was slightly erythematous with moderate dorsal-medial swelling and mild dorsal-lateral swelling, with severe tenderness to palpation over the medial retro-malleolar region. Range of motion and manual muscle testing were pain limited throughout. Ultrasound examination revealed a left posterior tibialis tendon sheath tenosynovitis with effusion and overlying soft tissue edema. Tendon sheath aspirate revealed sodium urate crystals and a white blood cell count of 6400/μL. Tendon sheath injection with a mixture of 1% lidocaine and dexamethasone 4 mg resulted in symptom resolution. Repeat ultrasound examination demonstrated no evidence of tibialis posterior tendon sheath effusion. This case is unique not only because acute gouty posterior tibialis tenosynovitis is very rare, particularly in a normouricemic individual, but also because the sonographic evidence of gouty infiltration into the posterior tibialis tendon and overlying subcutaneous tissue considerably aided in arriving at the correct diagnosis in a timely manner.

  3. Posteriorly migrated thoracic disc herniation: a case report

    Directory of Open Access Journals (Sweden)

    Miyakoshi Naohisa

    2013-02-01

    Full Text Available Abstract Introduction Posterior epidural migration of thoracic disc herniation is extremely rare but may occur in the same manner as in the lumbar spine. Case presentation A 53-year-old Japanese man experienced sudden onset of incomplete paraplegia after lifting a heavy object. Magnetic resonance imaging revealed a posterior epidural mass compressing the spinal cord at the T9-T10 level. The patient underwent emergency surgery consisting of laminectomy at T9-T10 with right medial facetectomy, removal of the mass lesion, and posterior instrumented fusion. Histological examination of the mass lesion yielded findings consistent with sequestered disc material. His symptoms resolved, and he was able to resume walking without a cane 4 weeks after surgery. Conclusions Pre-operative diagnosis of posterior epidural migration of herniated thoracic disc based on magnetic resonance imaging alone may be overlooked, given the rarity of this pathology. However, this entity should be considered among the differential diagnoses for an enhancing posterior thoracic extradural mass.

  4. Predisposing factors in posterior circulation infarcts: a vascular morphological assessment.

    Science.gov (United States)

    Çoban, Gökçen; Çifçi, Egemen; Yildirim, Erkan; Ağıldere, Ahmet Muhteşem

    2015-05-01

    The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving.

  5. Predisposing factors in posterior circulation infarcts: a vascular morphological assessment

    International Nuclear Information System (INIS)

    Coban, Goekcen; Cifci, Egemen; Yildirim, Erkan; Agildere, Ahmet Muhtesem

    2015-01-01

    The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving. (orig.)

  6. Features extraction in anterior and posterior cruciate ligaments analysis.

    Science.gov (United States)

    Zarychta, P

    2015-12-01

    The main aim of this research is finding the feature vectors of the anterior and posterior cruciate ligaments (ACL and PCL). These feature vectors have to clearly define the ligaments structure and make it easier to diagnose them. Extraction of feature vectors is obtained by analysis of both anterior and posterior cruciate ligaments. This procedure is performed after the extraction process of both ligaments. In the first stage in order to reduce the area of analysis a region of interest including cruciate ligaments (CL) is outlined in order to reduce the area of analysis. In this case, the fuzzy C-means algorithm with median modification helping to reduce blurred edges has been implemented. After finding the region of interest (ROI), the fuzzy connectedness procedure is performed. This procedure permits to extract the anterior and posterior cruciate ligament structures. In the last stage, on the basis of the extracted anterior and posterior cruciate ligament structures, 3-dimensional models of the anterior and posterior cruciate ligament are built and the feature vectors created. This methodology has been implemented in MATLAB and tested on clinical T1-weighted magnetic resonance imaging (MRI) slices of the knee joint. The 3D display is based on the Visualization Toolkit (VTK). Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Predisposing factors in posterior circulation infarcts: a vascular morphological assessment

    Energy Technology Data Exchange (ETDEWEB)

    Coban, Goekcen; Cifci, Egemen; Yildirim, Erkan; Agildere, Ahmet Muhtesem [Baskent University Faculty of Medicine, Department of Radiology, Konya (Turkey)

    2015-05-01

    The aim of the study is to assess the effect of shape, diameter, elongation and deviation criteria of basilar artery (BA), convergence angle and diameter variations of vertebral arteries, and concurrent chronic diseases on posterior circulation infarcts. Between January 2010 and May 2013, 186 patients who underwent brain and diffusion magnetic resonance imaging (MRI) with suspected cerebrovascular accident and were diagnosed with posterior circulation infarct and 120 infarct negative control subjects were included in this case-control retrospective study. Vertebral artery (VA) and BA diameter, right (R) and left (L) VA angles at the level of bifurcation, and BA elongation-deviation, and shape of BA were assessed in a total of 306 subjects. Ischemic lesions in the posterior circulation were classified according to their anatomical location and vascular perfusion areas. No significant difference was noted between the control and patient groups with respect to BA diameter (p = 0.676). The most effective risk factors for posterior circulation infarcts were as follows: BA elongation of 2 or 3, BA transverse location of 2 or 3, increase in left VA angle, and history of hypertension, hypercholesterolemia, and diabetes mellitus. Our results suggest that prominent elongation and deviation, C and J shape of BA, and increased L VA angle may be the predictors of at-risk patients in posterior circulation infarcts. Reporting marked morphological BA and VA variations detected at routine brain MRI will aid in selection of patients. Timely detection and treatment of at-risk patients may be life-saving. (orig.)

  8. Flexor Digitorum Accessorius Longus: Importance of Posterior Ankle Endoscopy

    Science.gov (United States)

    Batista, Jorge Pablo; del Vecchio, Jorge Javier; Golanó, Pau; Vega, Jordi

    2015-01-01

    Endoscopy for the posterior region of the ankle through two portals is becoming more widespread for the treatment of a large number of conditions which used to be treated with open surgery years ago. The tendon of the flexor hallucis longus (FHL) travels along an osteofibrous tunnel between the posterolateral and posteromedial tubercles of the talus. Chronic inflammation of this tendon may lead to painful stenosing tenosynovitis. The aim of this report is to describe two cases depicting an accessory tendon which is an anatomical variation of the flexor hallucis longus in patients with posterior friction syndrome due to posterior ankle impingement and associated with a posteromedial osteochondral lesion of the talus. The anatomical variation (FDAL) described was a finding during an endoscopy of the posterior region of the ankle, and we have spared it by sectioning the superior flexor retinaculum only. The accessory flexor digitorum longus is an anatomical variation and should be taken into account when performing an arthroscopy of the posterior region of the ankle. We recommend this treatment on this type of injury although we admit this does not make a definite conclusion. PMID:26060592

  9. Flexor Digitorum Accessorius Longus: Importance of Posterior Ankle Endoscopy

    Directory of Open Access Journals (Sweden)

    Jorge Pablo Batista

    2015-01-01

    Full Text Available Endoscopy for the posterior region of the ankle through two portals is becoming more widespread for the treatment of a large number of conditions which used to be treated with open surgery years ago. The tendon of the flexor hallucis longus (FHL travels along an osteofibrous tunnel between the posterolateral and posteromedial tubercles of the talus. Chronic inflammation of this tendon may lead to painful stenosing tenosynovitis. The aim of this report is to describe two cases depicting an accessory tendon which is an anatomical variation of the flexor hallucis longus in patients with posterior friction syndrome due to posterior ankle impingement and associated with a posteromedial osteochondral lesion of the talus. The anatomical variation (FDAL described was a finding during an endoscopy of the posterior region of the ankle, and we have spared it by sectioning the superior flexor retinaculum only. The accessory flexor digitorum longus is an anatomical variation and should be taken into account when performing an arthroscopy of the posterior region of the ankle. We recommend this treatment on this type of injury although we admit this does not make a definite conclusion.

  10. Lava delta deformation as a proxy for submarine slope instability

    Science.gov (United States)

    Di Traglia, Federico; Nolesini, Teresa; Solari, Lorenzo; Ciampalini, Andrea; Frodella, William; Steri, Damiano; Allotta, Benedetto; Rindi, Andrea; Marini, Lorenzo; Monni, Niccolò; Galardi, Emanuele; Casagli, Nicola

    2018-04-01

    The instability of lava deltas is a recurrent phenomenon affecting volcanic islands, which can potentially cause secondary events such as littoral explosions (due to interactions between hot lava and seawater) and tsunamis. It has been shown that Interferometric Synthetic Aperture Radar (InSAR) is a powerful technique to forecast the collapse of newly emplaced lava deltas. This work goes further, demonstrating that the monitoring of lava deltas is a successful strategy by which to observe the long-term deformation of subaerial-submarine landslide systems on unstable volcanic flanks. In this paper, displacement measurements derived from Synthetic Aperture Radar (SAR) imagery were used to detect lava delta instability at Stromboli volcano (Italy). Recent flank eruptions (2002-2003, 2007 and 2014) affected the Sciara del Fuoco (SdF) depression, created a "stacked" lava delta, which overlies a pre-existing scar produced by a submarine-subaerial tsunamigenic landslide that occurred on 30 December 2002. Space-borne X-band COSMO-SkyMED (CSK) and C-band SENTINEL-1A (SNT) SAR data collected between February 2010 and October 2016 were processed using the SqueeSAR algorithm. The obtained ground displacement maps revealed the differential ground motion of the lava delta in both CSK and SNT datasets, identifying a stable area (characterized by less than 2 mm/y in both datasets) within the northern sector of the SdF and an unstable area (characterized by velocity fields on the order of 30 mm/y and 160 mm/y in the CSK and SNT datasets, respectively) in the central sector of the SdF. The slope stability of the offshore part of the SdF, as reconstructed based on a recently performed multibeam bathymetric survey, was evaluated using a 3D Limit Equilibrium Method (LEM). In all the simulations, Factor of Safety (F) values between 0.9 and 1.1 always characterized the submarine slope between the coastline and -250 m a.s.l. The critical surfaces for all the search volumes corresponded to

  11. Vegetated Flow down a Slope under a Uniform Rainfall

    Science.gov (United States)

    Hsieh, P.; Hu, S.

    2012-12-01

    To understand the effect of vegetation on flow velocity and water depth, a semi-analytical approach was proposed to study flow passing over a finite thick vegetated area under a uniform rainfall event. In this study, the flow region is divided into three layers-- homogenous water layer, mixed water-plant layer and finite thick soil layer (briefly denoted by water layer, vegetation layer, and soil layer). The flow of the water layer is governed by the Navier-Stokes equations. The vegetation and soil layers are both regarded as porous media and a laminar model modified from Biot's theory of poroelasticity is applied. The semi-closed solutions were obtained via the Runge-Kutta method. The flow profiles on a vegetated slope with different slopes were graphed. Accordingly, the relation between vegetation and water depth was divided into three patterns-- submerged vegetation, emergent vegetation and submerged-emergent vegetation. The velocity profiles for these patterns at each location were estimated. The retardation of vegetation causes that the velocity in vegetation layer is much slower than that in water layer and thus an inflection point exists inside the vegetation layer. This phenomenon doesn't happen in the case of emergent vegetation. The nonzero velocity at the ground surface is also estimated, and the velocity in the soil layer decays quickly to a constant. The shear stress distribution for different diameters of vegetation in the case of submerged vegetation was estimated. There is a positive correlation between the diameter of vegetation and the retardation of vegetation. Therefore the shear stress is influenced by the diameter of vegetation. The shear stress inside the water layer increases with the diameter of vegetation while the shear stress inside the vegetation layer decreases with the diameter of vegetation. This implies that the vegetation on the slope can protect the soil erosion.

  12. Antiproton Target

    CERN Multimedia

    1980-01-01

    Antiproton target used for the AA (antiproton accumulator). The first type of antiproton production target used from 1980 to 1982 comprised a rod of copper 3mm diameter and 120mm long embedded in a graphite cylinder that was itself pressed into a finned aluminium container. This assembly was air-cooled and it was used in conjunction with the Van der Meer magnetic horn. In 1983 Fermilab provided us with lithium lenses to replace the horn with a view to increasing the antiproton yield by about 30%. These lenses needed a much shorter target made of heavy metal - iridium was chosen for this purpose. The 50 mm iridium rod was housed in an extension to the original finned target container so that it could be brought very close to the entrance to the lithium lens. Picture 1 shows this target assembly and Picture 2 shows it mounted together with the lithium lens. These target containers had a short lifetime due to a combination of beam heating and radiation damage. This led to the design of the water-cooled target in...

  13. HDMR methods to assess reliability in slope stability analyses

    Science.gov (United States)

    Kozubal, Janusz; Pula, Wojciech; Vessia, Giovanna

    2014-05-01

    Stability analyses of complex rock-soil deposits shall be tackled considering the complex structure of discontinuities within rock mass and embedded soil layers. These materials are characterized by a high variability in physical and mechanical properties. Thus, to calculate the slope safety factor in stability analyses two issues must be taken into account: 1) the uncertainties related to structural setting of the rock-slope mass and 2) the variability in mechanical properties of soils and rocks. High Dimensional Model Representation (HDMR) (Chowdhury et al. 2009; Chowdhury and Rao 2010) can be used to carry out the reliability index within complex rock-soil slopes when numerous random variables with high coefficient of variations are considered. HDMR implements the inverse reliability analysis, meaning that the unknown design parameters are sought provided that prescribed reliability index values are attained. Such approach uses implicit response functions according to the Response Surface Method (RSM). The simple RSM can be efficiently applied when less than four random variables are considered; as the number of variables increases, the efficiency in reliability index estimation decreases due to the great amount of calculations. Therefore, HDMR method is used to improve the computational accuracy. In this study, the sliding mechanism in Polish Flysch Carpathian Mountains have been studied by means of HDMR. The Southern part of Poland where Carpathian Mountains are placed is characterized by a rather complicated sedimentary pattern of flysh rocky-soil deposits that can be simplified into three main categories: (1) normal flysch, consisting of adjacent sandstone and shale beds of approximately equal thickness, (2) shale flysch, where shale beds are thicker than adjacent sandstone beds, and (3) sandstone flysch, where the opposite holds. Landslides occur in all flysch deposit types thus some configurations of possible unstable settings (within fractured rocky

  14. Evolution of continental slope gullies on the northern california margin

    Science.gov (United States)

    Spinelli, G.A.; Field, M.E.

    2001-01-01

    A series of subparallel, downslope-trending gullies on the northern California continental slope is revealed on high-resolution seismic reflection profiles imaging the uppermost 50 m of sediment. The gullies are typically 100 m wide and have 1 to 3 m of relief. They extend for 10 to 15 km down the slope and merge into larger channels that feed the Trinity Canyon. In the lower half of the 50 m stratigraphic section, the gullies increase in both relief and number up section, to maxima at a surface 5 to 10 m below the last glacial maximum lowstand surface. Gully relief increased as interfluves aggraded more rapidly than thalwegs. Erosion is not evident in the gully bottoms, therefore gully growth was probably due to reduced sediment deposition within the gullies relative to that on interfluves. As the gullies increased in relief, their heads extended upslope toward the shelfbreak. At all times, a minimum of 10 km of non-gullied upper slope and shelf stretched between the heads of the gullies and the paleo-shoreline; the gullies did not connect with a subaerial drainage network at any time. Gully growth occurred when the gully heads were in relatively shallow water (??? 200 m paleo-water depth) and were closest to potential sediment sources. We suggest that prior to the last glacial maximum, the Mad River, then within 10 km of the gully heads, supplied sediment to the upper slope, which fed downslope-eroding sediment flows. These flows removed sediment from nearly parallel gullies at a rate slightly slower than sediment accumulation from the Eel River, 40 km to the south. The process or processes responsible for gully growth and maintenance prior to the last glacial maximum effectively ceased following the lowstand, when sea level rose and gully heads lay in deeper water (??? 300 m water depth), farther from potential sediment sources. During sea-level highstand, the Mad River is separated from the gully heads by a shelf 30 km wide and no longer feeds sediment flows

  15. A New Formula for Front Slope Recession of Berm Breakwaters

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Burcharth, Hans F.

    2010-01-01

    The front slope stability of breakwaters with a homogeneous berm was studied in a large number of two dimensional model tests at Aalborg University, Denmark. The results are presented together with a new formula for prediction of the berm recession which is the most important parameter...... for describing the reshaping. The formula has also been calibrated and validated against model test data from other researchers. The significance of the new design formula is that it predicts berm recession much better than the existing methods, especially in case of more stable structures....

  16. Mixing by internal waves impinging on a slope

    Science.gov (United States)

    Chalamalla, Vamsi Krishna; Sarkar, Sutanu

    2012-11-01

    Direct and large eddy simulations are performed to study the mixing that occurs when internal waves interact with critical and near-critical sloping bottom. Different horizontal wave lengths up to O ~ 1 km are considered at a moderate value of Froude number. The pathway from the input wave energy to the irreversible mixing of density field is explored. Diagnostics such as turbulent kinetic energy and density variance budget are used to obtain the phasing of turbulence and associated mixing. Energy transfer to higher harmonics and subharmonics is also quantified.

  17. Different elevational patterns of rodent species richness between the southern and northern slopes of a mountain.

    Science.gov (United States)

    Shuai, Ling-Ying; Ren, Chun-Lei; Yan, Wen-Bo; Song, Yan-Ling; Zeng, Zhi-Gao

    2017-08-18

    Studies on elevational gradients in biodiversity have accumulated in recent decades. However, few studies have compared the elevational patterns of diversity between the different slopes of a single mountain. We investigated the elevational distribution of rodent diversity (alpha and beta diversity) and its underlying mechanisms along the southern and northern slopes of Mt. Taibai, the highest mountain in the Qinling Mountains, China. The species richness of rodents on the two slopes showed distinct distribution patterns, with a monotonically decreasing pattern found along the southern slope and a hump-shaped elevational pattern evident along the northern slope. Multi-model inference suggested that temperature was an important explanatory factor for the richness pattern along the southern slope, and the mid-domain effect (MDE) was important in explaining the richness pattern along the northern slope. The two slopes also greatly differed in the elevational patterns of species turnover, with the southern slope demonstrating a U-shaped curve and the northern slope possessing a roughly hump-shaped pattern. Our results suggest that even within the same mountain, organisms inhabiting different slopes may possess distinct diversity patterns, and the underlying mechanisms may also differ. The potential role of the factors associated with slope aspect in shaping diversity, therefore, cannot be ignored.

  18. Influence of flow on thawing of underwater slopes and the pace ...

    African Journals Online (AJOL)

    ... hydraulic laboratory of department of architecture & civil engineering RUDN University was performed studies of destruction of underwater and above-water coastal slopes in conditions simulating permafrost, depending on the soil type, the initial slope, and the slope angle. It was shown by authors, the speed of erosion of ...

  19. The Impact of Vegetative Slope on Water Flow and Pollutant Transport through Embankments

    Directory of Open Access Journals (Sweden)

    Liting Sheng

    2017-06-01

    Full Text Available Embankments are common structures along rivers or lakes in riparian zones in plain areas. They should have natural slopes instead of slopes covered by concrete or other hard materials, in order to rebuild sustainable ecosystems for riparian zones. This study was conducted to evaluate the effects of vegetative slopes on water flow and pollutant transport through the embankments. Three embankments with different slope treatments (a bare slope, a slope covered in centipede grass, a slope covered in tall fescue were examined, and three inflow applications of pollute water with different concentration of total nitrogen (TN and total phosphorus (TP used to simulate different agricultural non-point pollution levels. The results showed that the water flux rates of the three embankments were relatively stable under all inflow events, and almost all values were higher than 80%. The embankments with vegetative slopes had better nitrogen removal than the bare slope under all events, and the one with tall fescue slope was best, but the benefits of vegetative slopes decreased with increasing inflow concentration. Moreover, there were no significant differences between the embankments on phosphorus removal, for which the reductions were all high (above 90% with most loads remaining in the front third of embankment bodies. Overall, the embankments with vegetative slopes had positive effects on water exchange and reducing non-point pollutant into lake or river water, which provides a quantitative scientific basis for the actual layout of lakeshores.

  20. Slope angle studies from multibeam sonar data on three seamounts in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.

    Slope angles are powerful morphometric tools. Slope angle studies in manganese nodule areas using the Multi Beam Sonar (MBS) data is useful to the mining geologist. A technique to convert depth grid generated from MBS data to slope angle values data...