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Sample records for fissured formations

  1. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-06-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║<001>] and gamma [ND║<111>] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  2. Anal fissure.

    PubMed

    Schlichtemeier, Steven; Engel, Alexander

    2016-02-01

    An anal fissure is a common, mostly benign, condition that can be acute or chronic. The diagnosis is usually made on history and physical examination, but further investigations are sometimes necessary. Primary fissures are usually benign and located in the posterior or anterior position. Secondary fissures are lateral or multiple and often indicate a more serious underlying pathology. The management of primary anal fissures is generally non-operative and includes increased dietary fibre, sitz baths, topical ointments and botulinum toxin injections. If these treatments are ineffective the patient will need a surgical referral. Secondary anal fissures require further investigation. Multidisciplinary management is preferable and is essential in the case of malignancy. PMID:27041801

  3. Anal fissure

    PubMed Central

    Schlichtemeier, Steven; Engel, Alexander

    2016-01-01

    SUMMARY An anal fissure is a common, mostly benign, condition that can be acute or chronic. The diagnosis is usually made on history and physical examination, but further investigations are sometimes necessary. Primary fissures are usually benign and located in the posterior or anterior position. Secondary fissures are lateral or multiple and often indicate a more serious underlying pathology. The management of primary anal fissures is generally non-operative and includes increased dietary fibre, sitz baths, topical ointments and botulinum toxin injections. If these treatments are ineffective the patient will need a surgical referral. Secondary anal fissures require further investigation. Multidisciplinary management is preferable and is essential in the case of malignancy. PMID:27041801

  4. Measurement of kinetic energy dissipation with gelatine fissure formation with special reference to gelatine validation.

    PubMed

    Jussila, Jorma

    2005-05-28

    Various methods for calculating the amount of kinetic energy dissipated by a bullet into ballistic gelatine have been suggested in literature. These methods were compared using the results of thirteen 9 mmx19 mm pistol and five 7.62 mmx 39 mm rifle bullets shot into 10% ballistic gelatine. The Wound Profile Method gave the highest correlation, 0.89, with the measured amounts of dissipated kinetic energy. The Fissure surface area and total crack length method gained 0.51 and 0.52, respectively. The experimental results were also compared with those from pig tests with the same bullet types. Using the z-test at 95% level of confidence no difference between impact velocity normalized bullet decelerations could be determined for the 9 mm bullet used. The same test showed significant difference for 7.62 mm bullets. That, however, can be considered to be the result of the bullet's tendency to tumble in non-homogenous living tissue causing significant dispersion of observed deceleration values. The results add further evidence supporting the validity of 10% gelatine at +4 degrees C as wound ballistic tissue simulant. The study also introduces the use of an elastic "shroud" to hold the gelatine in place, to some extent reduce the effects of asymmetric expansion of the gelatine and to simulate the expansion suppression effect of surrounding tissues. PMID:15837008

  5. Anal fissure - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100154.htm Anal fissure - series—Normal anatomy To use the sharing ... rectum through which passes stool during defecation. The anal sphincter is a critical mechanism for control of ...

  6. Accessory fissures of the lung

    SciTech Connect

    Godwin, D.; Tarver, R.D.

    1985-01-01

    Accessory fissures of the lung are commonly observed in lung specimens, but are often unappreciated or misinterpreted in radiographs and computer tomographic (CT) scans. They usually occur at the boundaries between bronchopulmonary segments. Most common are the inferior accessory fissure, which demarcates the medial basal segment; the superior accessory fissure, which demarcates the superior segment; and the left minor fissure, which demarcates the lingula. This essay will illustrate the findings of the common accessory fissures both on plain radiographs and on CT scans.

  7. Study of the deformation mechanism of the Gaoliying ground fissure

    NASA Astrophysics Data System (ADS)

    Cheng, G.; Wang, H.; Luo, Y.; Guo, H.

    2015-11-01

    The Gaoliying ground fissure in Beijing has caused building cracking and road damage, and has seriously influenced city construction. Based on investigations and trenching, the influences of the fault and the variation of groundwater levels on the formation mechanism of the Gaoliying ground fissure were investigated by using FLAC3D. The results indicated that (1) the surface location of Gaoliying fissure is controlled by the underlying normal fault activity, and over pumping further exacerbates development of the ground fissure; (2) when the groundwater level declines, obvious differential settlement occurs at both sides of the ground fissure, in which greater settlement occurs in the vicinity of the hanging wall, the greater the distance from the hanging wall, the smaller the ground subsidence, however smaller ground subsidence occurs in the vicinity of the footwall, the greater the distance from the footwall, the greater the ground subsidence; (3) the vertical velocity of the ground fissure triggered by the fault activity and groundwater decline ranges from 15.5 to 18.3 mm a-1, which is basically in line with the monitoring data. The fault activity contributes about 28-39 %, and the groundwater contributes about 61-72 % to the deformation of the ground fissure, respectively.

  8. Shallow Subsurface Structures of Volcanic Fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Nash, J.; Mitchell, K. L.; Parness, A.

    2015-12-01

    Volcanic fissure vents are a difficult geologic feature to quantify. They are often too thin to document in detail with seismology or remote geophysical methods. Additionally, lava flows, lava drain back, or collapsed rampart blocks typically conceal a fissure's surface expression. For exposed fissures, quantifying the surface (let along sub0surface) geometric expression can become an overwhelming and time-consuming task given the non-uniform distribution of wall irregularities, drain back textures, and the larger scale sinuosity of the whole fissure system. We developed (and previously presented) VolcanoBot to acquire robust characteristic data of fissure geometries by going inside accessible fissures after an eruption ends and the fissure cools off to <50 C. Data from VolcanoBot documents the fissure conduit geometry with a near-IR structured light sensor, and reproduces the 3d structures to cm-scale accuracy. Here we present a comparison of shallow subsurface structures (<30 m depth) within the Mauna Ulu fissure system and their counterpart features at the vent-to-ground-surface interface. While we have not mapped enough length of the fissure to document sinuosity at depth, we see a self-similar pattern of irregularities on the fissure walls throughout the entire shallow subsurface, implying a fracture mechanical origin similar to faults. These irregularities are, on average, 1 m across and protrude 30 cm into the drained fissure. This is significantly larger than the 10% wall roughness addressed in the engineering literature on fluid dynamics, and implies that magma fluid dynamics during fissure eruptions are probably not as passive nor as simple as previously thought. In some locations, it is possible to match piercing points across the fissure walls, where the dike broke the wall rock in order to propagate upwards, yet in other locations there are erosional cavities, again, implying complex fluid dynamics in the shallow sub-surface during fissure eruptions.

  9. Modeling of earth fissures caused by land subsidence due to groundwater withdrawal

    NASA Astrophysics Data System (ADS)

    Panda, B. B.; Rucker, M. L.; Fergason, K. C.

    2015-11-01

    Land subsidence and earth fissures are phenomena related to groundwater withdrawal in a sedimentary basin. If the rock basement or basin lithology is irregular, both vertical and horizontal displacements can be induced due to differential settlement and tensile stresses appearing in the soil mass. If the differential settlement is of sufficient magnitude, earth fissuring can occur within tensile zones. The magnitudes of compaction and fissure geometry are closely related to the thickness and skeletal compressibility of fine-grained sediments within the aquifer system. Land subsidence and earth fissuring were modeled by employing a two-dimensional (2-D) coupled seepage and stress-strain finite element analysis. The basin bedrock geometry, lithological variation, measurements of surface displacements, and changes in hydraulic head were the critical input parameter for the subsidence modeling. Simulation results indicate that strain had exceeded the approximate threshold for fissure formation of 0.02 to 0.06 % in the area of the identified fissures. The numerical model was used to predict future subsidence and potential earth fissures for flood control structures within the metro Phoenix area.

  10. A polarized light and scanning electron microscopic study of human fissure and lingual enamel of unerupted mandibular third molars.

    PubMed

    Ekstrand, K; Holmen, L; Qvortrup, K

    1999-01-01

    Using histological and ultrastructural techniques the aims of this study were to investigate whether the mineralization pattern and surface microanatomy of the caries-susceptible fissure enamel were different from those on the caries-inactive lingual surface. The material consisted of 31 unerupted third mandibular molars. The specimens were initially grouped into four categories: (1) without, (2) with initial, (3) with almost completed and (4) with completed root formation. One ground section with fissure-like morphology was selected from each tooth. Using water as a medium the observed birefringence was negative along the lingual and fissure transverses in specimens with almost completed and with completed root formation, while the observed birefringence was positive at different distances in the enamel in sections representing less maturation stages. Qualitative imbibition studies revealed hypomineralized enamel in the lower part of the fissures in specimens representing almost and completed root formation. Imbibed in quinoline, parts of the hypomineralized enamel behaved like a molecular sieve due to the presence of micropores, indicating that the structural arrangement is different from that in the enamel adjacent to this areas. After division of the sections into a lingual and a buccal part, SEM features were described from lower and upper parts of the buccal fissure wall and on lingual enamel in the area corresponding to the bottom part of the fissure. The surface microanatomy varied greatly. Negative developmental irregularities such as fissures and holes were associated with the immature enamel, while matured enamel - particularly fissures - housed many positive developmental irregularities such as enamel caps and protrusions. The crystal size in the mature specimens appeared smaller and more uniform than the crystals from the immature specimens. Apart from the occurrence of hypomineralized enamel in fissures and numerous positive developmental

  11. [Anal fissure--a new therapy concept].

    PubMed

    Hetzer, F H; Baumann, M; Röthlin, M

    2000-08-24

    The anal fissure is one of the most frequent causes for anal pain. Conservative treatment usually consists of laxatives, local anesthetics and nitroglycerin cream. These therapies have a high recurrency rate. Surgical interventions, i.e. manual dilatation and sphincterotomy are fraught with the danger of fecal incontinence. The completely reversible effect of botulinum toxin injection opens new possibilities in the treatment of anal fissures. Its use is discussed as part of a 3-stage therapeutic regimen.

  12. Robust pulmonary lobe segmentation against incomplete fissures

    NASA Astrophysics Data System (ADS)

    Gu, Suicheng; Zheng, Qingfeng; Siegfried, Jill; Pu, Jiantao

    2012-03-01

    As important anatomical landmarks of the human lung, accurate lobe segmentation may be useful for characterizing specific lung diseases (e.g., inflammatory, granulomatous, and neoplastic diseases). A number of investigations showed that pulmonary fissures were often incomplete in image depiction, thereby leading to the computerized identification of individual lobes a challenging task. Our purpose is to develop a fully automated algorithm for accurate identification of individual lobes regardless of the integrity of pulmonary fissures. The underlying idea of the developed lobe segmentation scheme is to use piecewise planes to approximate the detected fissures. After a rotation and a global smoothing, a number of small planes were fitted using local fissures points. The local surfaces are finally combined for lobe segmentation using a quadratic B-spline weighting strategy to assure that the segmentation is smooth. The performance of the developed scheme was assessed by comparing with a manually created reference standard on a dataset of 30 lung CT examinations. These examinations covered a number of lung diseases and were selected from a large chronic obstructive pulmonary disease (COPD) dataset. The results indicate that our scheme of lobe segmentation is efficient and accurate against incomplete fissures.

  13. Earth fissures and localized differential subsidence.

    USGS Publications Warehouse

    Holzer, Thomas L.; Pampeyan, Earl H.

    1981-01-01

    Long linear tension cracks associated with declining groundwater levels at four sites in subsiding areas in south-central Arizona, Fremont Valley, California, and Las Vegas Valley, Nevada, occur near points of maximum convex-upward curvature in subsidence profiles oriented perpendicular to the cracks. Profiles are based on repeated precise vertical control surveys of lines of closely spaced bench marks. Association of these fissures with zones of localized differential subsidence indicates that linear earth fissures are caused by horizontal tensile strains probably resulting from localized differential compaction. Horizontal tensile strains across the fissures at the point of maximum convex-upward curvature, ranging from approximately 100 to 700 microstrains (0.01 to 0.07% per year), were indicated based on measurements with a tape or electronic distance meter.

  14. Effect of surface fissure on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Sailhac, P.; Gance, J.; Malet, J.

    2013-12-01

    Fissures are features of interest, prone to create preferential flow path, modifying locally the soil hydrogeological behavior. Electrical Resistivity Tomography (ERT) is a suitable tool to monitor such preferential flow path. However, this technique is not efficient in the presence of surface fissure, due to a bad resistivity recovering around the fissure vicinity during the inversion process. Therefore, we propose a description of fissure effect on raw apparent resistivity on three resistivity arrays. The purposes of the study are multiple. First, we aim at making ERT users aware of surface fissure effect, and propose a first help to interpret basically resistivity pseudo sections. Second, we propose to ERT users to automatically conduct a surface fissure survey on the studied profile, in order to consider each fissure in a forward DC model and to suppress their effect. Finally, this study is only a first step toward 2D fissure shape inversion, and time-lapse monitoring of fissure drying and filling. In this study, we create a fissure model based on different geomorphological descriptors. After describing the FEM-DC forward modeling strategy, we investigate the fissure effect on pseudo section of apparent resistivity for a Wenner-Schlumberger (WS), a dipole-dipole (DD) and a gradient (GRAD) array. We determine a fissure detectability threshold for each array and perform a sensitivity analysis on the different fissure parameters (position, width, depth, dip angles...). The crack filling or drying effect is also investigated. The possibility to remove fissure effect and to propose a first interpretation of time-lapse data is illustrated on real data. This study show again the higher sensitivity of the DD array compared to the GRAD and WS arrays. Not only the maximal amplitude in the pseudo section is higher for the DD array, but also the anomaly pattern created by the fissure is much larger for this acquisition geometry. The minimal depth detectable for the DD

  15. Double-porosity models for a fissured groundwater reservoir with fracture skin.

    USGS Publications Warehouse

    Moench, A.F.

    1984-01-01

    Theories of flow to a well in a double-porosity groundwater reservoir are modified to incorporate effects of a thin layer of low-permeability material or fracture skin that may be present at fracture-block interfaces as a result of mineral deposition or alteration. The commonly used theory for flow in double-porosity formations that is based upon the assumption of pseudo-steady state block-to-fissure flow is shown to be a special case of the theory presented in this paper. The latter is based on the assumption of transient block-to-fissure flow with fracture skin.-from Author

  16. Tensions and Fissures: The Politics of Standardised Testing and Accountability in Ontario, 1995-2015

    ERIC Educational Resources Information Center

    Pinto, Laura Elizabeth

    2016-01-01

    While Ontario has received international accolades for its enactment of province-wide standardised testing upon the formation of the Education Quality and Accountability Office (EQAO), a closer look at provincial assessments over a 20-year span reveals successes as well as systemic tensions and fissures. The purpose of this paper is twofold.…

  17. Influence of matrix diffusion and exchange reactions on radiocarbon ages in fissured carbonate aquifers

    SciTech Connect

    Maloszewski, P. ); Zuber, A. )

    1991-08-01

    The parallel fissure model coupled with the equation of diffusion into the matrix and with exchange reaction equations has been used to derive a simple formula for estimating the influence of matrix porosity and reaction parameters on the determination of radiocarbon ages in fissured carbonate rocks. Examples of evidently too great radiocarbon ages in carbonate formations, which are not explainable by models for the initial {sup 14}C corrections, can easily be explained by this formula. Parameters obtained for a chalk formation from a known multitracer experiment combined with a pumping test suggest a possibility of {sup 14}C ages more than three orders of magnitude greater than the ages which would be observed if the radiocarbon transport took place only in the mobile water in the fissures. It is shown that contrary to the solute movement on a small scale and with a variable input, the large-scale movement, characteristic for the {sup 14}C dating, does not necessarily require the knowledge of kinetic parameters, because they may be replaced by the distribution coefficient. Discordant tritium and {sup 14}C concentrations are commonly interpreted as a proof of mixing either in the aquifer or at the discharge site. For fissured carbonate formations, however, an alternative explanation is given by the derived model showing a considerable delay of {sup 14}C with respect to nonsorbable tracers.

  18. Hydraulic fracturing in tight, fissured media

    SciTech Connect

    Warpinski, N.R. )

    1991-02-01

    Large volumes of natural gas are found in tight, fissured reservoirs. Hydraulic fracturing can enhance recovery, but many complications, such as pressure-sensitive or accelerated leakoff, damage, and complex fracturing, arise during treatment of such reservoirs. This paper reports that special procedures generally should be considered during breakdown and fracturing of these reservoirs. In addition, the use of alternative stimulation strategies may be beneficial.

  19. [Fissures in biliary calculi. Personal contribution (author's transl)].

    PubMed

    Nano, M; Potenzoni, F; Camandona, M; Casalegno, P A

    1979-04-01

    In a series of 70 patients suffering from biliary lithiasis, the roentgenologic findings of fissures in the calculi was observed in 5 cases examined by means of cholecystography and in 7 cases who underwent cholangiocholecystography. Fissures were demonstrated 11 times in calculi after surgery. The "Mercedes-Benz" sign was never observed at the abdominal examination without contrast medium. The presence of fissures may be an additional sign in the radiologic diagnosis of biliary calculi, but its value is not determinant.

  20. [Fissures in biliary calculi. Personal contribution (author's transl)].

    PubMed

    Nano, M; Potenzoni, F; Camandona, M; Casalegno, P A

    1979-04-01

    In a series of 70 patients suffering from biliary lithiasis, the roentgenologic findings of fissures in the calculi was observed in 5 cases examined by means of cholecystography and in 7 cases who underwent cholangiocholecystography. Fissures were demonstrated 11 times in calculi after surgery. The "Mercedes-Benz" sign was never observed at the abdominal examination without contrast medium. The presence of fissures may be an additional sign in the radiologic diagnosis of biliary calculi, but its value is not determinant. PMID:550199

  1. [Test of an electronic fissure caries detector].

    PubMed

    Pieper, K; Visser, H; Hülsmann, M; Wahner, M

    1990-11-01

    The reliability of an electronic detector for caries in pits and fissures was tested by means of physical measurements, histological sections and clinical evaluation. The device measures the ohmic resistance of the tooth, technical data are given. First we compared measurements and histological sections of teeth due for extraction. The results indicated a high sensitivity of the device for caries, false positive diagnoses did not occur. Based on this, a clinical evaluation on 179 teeth was performed. Under practical conditions the sensitivity of the electronic detector (0.77) was lower than in the first part of the study; conventional diagnosis revealed more carious lesions in dentine (sensitivity: 0.82).

  2. Corrections of surface fissure effect on apparent resistivity measurements

    NASA Astrophysics Data System (ADS)

    Gance, J.; Sailhac, P.; Malet, J.-P.

    2015-02-01

    Electrical resistivity tomography (ERT) is a useful tool to detect and track water flow paths in the subsoil. However, measurements are strongly affected by subsurface heterogeneities such as fissures of different sizes and genesis (shrinking-swelling, macropores and deformation). In this work, we focus on surface fissures characterized by dimensions lower than the interelectrode spacing and correct their effect on apparent resistivity pseudo-sections by incorporating fissure geometry in the topography. We show that fissures with depths greater than 0.10 times the interelectrode spacing for a dipole-dipole array and equal to 0.16 for the gradient array and the Wenner-Schlumberger arrays create significant anomalies (greater than 5 per cent) in the pseudo-section. Surface fissure widths and dip angles have little effect with respect to the fissure depths which can increase the apparent resistivity up to 200 per cent. The clogging of the fissures with water or soil material decreases the anomaly effect linearly with the percentage of filling. The correction of apparent resistivity values is possible for relatively simple fissure geometries and only requires a manual survey of the surface fissures. It allows to improve the quality of the inverted resistivity section by mitigating the inversion artefacts and therefore a better interpretation.

  3. A Geophysical Study of Fissures in Pahrump, Nevada

    NASA Astrophysics Data System (ADS)

    Hirsch, A. C.; McEwan, M. J.; Howley, R. A.; Mehling, J. B.; Snelson, C. M.; Drohan, P.

    2004-12-01

    Earth fissures are surface expressions of deep fracturing subsidence systems caused by groundwater withdrawl greater than aquifer recharge. This type of subsidence is most common in arid environments of the south western U.S. such as, Las Vegas, NV, Phoenix, AZ, and areas in New Mexico. In addition, fissures have recently been identified in the Pahrump Valley in southwestern Nevada just west of Las Vegas. The city of Pahrump has experienced an increase in population and economic growth. This growth has lead to a higher demand in the use of the areas natural resources. One major concern is groundwater pumping and over-watering of the land surface. Pahrump has experienced significant differential subsidence within the valley causing significant structural damage to infrastructure. This differential subsidence is most readily identified by its surface expression as fissures. Earth fissures are not only shallow surface features but can be 10's of meters deep and 100's of meters long. These ground failures can be exacerbated by faults at depth, shallow bedrock, and/or differential compaction. However, the most significant cause is from groundwater withdrawl. Several geophysical methods were performed on the fissures to better understand their subsurface expression, trend, and ultimately their affect on the city of Pahrump. Seismic refraction, reflection, ground penetrating radar (GPR), and gravity measurements were performed on the fissures and surrounding area including local faults. Our initial studies show the fissures propagating for long distances, in a variety of shapes, and trending in a north-south direction. Initial GPR studies show high fissure reflections at approximately 1 and 1.5 meters along with general slumping features below these reflections. Fissures are an unmitigatable problem. Our results will help identify fissures in the area that do not have a surface expression as well as mapping the current fissures and their extent. These results can be used

  4. A visualization system for CT based pulmonary fissure analysis

    NASA Astrophysics Data System (ADS)

    Pu, Jiantao; Zheng, Bin; Park, Sang Cheol

    2009-02-01

    In this study we describe a visualization system of pulmonary fissures depicted on CT images. The purpose is to provide clinicians with an intuitive perception of a patient's lung anatomy through an interactive examination of fissures, enhancing their understanding and accurate diagnosis of lung diseases. This system consists of four key components: (1) region-of-interest segmentation; (2) three-dimensional surface modeling; (3) fissure type classification; and (4) an interactive user interface, by which the extracted fissures are displayed flexibly in different space domains including image space, geometric space, and mixed space using simple toggling "on" and "off" operations. In this system, the different visualization modes allow users not only to examine the fissures themselves but also to analyze the relationship between fissures and their surrounding structures. In addition, the users can adjust thresholds interactively to visualize the fissure surface under different scanning and processing conditions. Such a visualization tool is expected to facilitate investigation of structures near the fissures and provide an efficient "visual aid" for other applications such as treatment planning and assessment of therapeutic efficacy as well as education of medical professionals.

  5. Fine Mapping and Introgressing a Fissure Resistance Locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in rice kernels that increase breakage among kernels when transported or milled, which decrease the value of processed rice. This study employed molecular gene tagging methods to ...

  6. Newer Classification System for Fissured Tongue: An Epidemiological Approach

    PubMed Central

    Sudarshan, Ramachandran; Sree Vijayabala, G.; Samata, Y.; Ravikiran, A.

    2015-01-01

    Introduction. Fissured tongue is a commonly encountered tongue disorder in dental practice. But there is a lack of data on different pattern, severity, and association of fissuring with various systemic disorders and other tongue anomalies. This study attempts to establish a classification system for fissured tongue and to know the correlation with the systemic health and other disorders of the tongue. Materials and Methods. A total of 1000 subjects between the age groups of 10 and 80 years were included in the study. Pattern of fissuring, allied systemic diseases, and related tongue anomalies were tabulated. Results. Out of 1000 subjects, 387 subjects presented with fissured tongue. Out of 387 subjects, hypertension was present in 57 cases, 18 subjects had diabetes, and 3 subjects had both hypertension and diabetes. Central longitudinal type was found to be the most common type of tongue fissuring. Conclusion. Fissured tongue has been found to be associated with certain systemic disease and further researches are required to know positive correlation. If a correlation exists, such disorders could be diagnosed earlier by identifying fissured tongue at an earlier age. PMID:26457087

  7. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    NASA Astrophysics Data System (ADS)

    Amrani, Salah

    La fabrication de l'aluminium est realisee dans une cellule d'electrolyse, et cette operation utilise des anodes en carbone. L'evaluation de la qualite de ces anodes reste indispensable avant leur utilisation. La presence des fissures dans les anodes provoque une perturbation du procede l'electrolyse et une diminution de sa performance. Ce projet a ete entrepris pour determiner l'impact des differents parametres de procedes de fabrication des anodes sur la fissuration des anodes denses. Ces parametres incluent ceux de la fabrication des anodes crues, des proprietes des matieres premieres et de la cuisson. Une recherche bibliographique a ete effectuee sur tous les aspects de la fissuration des anodes en carbone pour compiler les travaux anterieurs. Une methodologie detaillee a ete mise au point pour faciliter le deroulement des travaux et atteindre les objectifs vises. La majorite de ce document est reservee pour la discussion des resultats obtenus au laboratoire de l'UQAC et au niveau industriel. Concernant les etudes realisees a l'UQAC, une partie des travaux experimentaux est reservee a la recherche des differents mecanismes de fissuration dans les anodes denses utilisees dans l'industrie d'aluminium. L'approche etait d'abord basee sur la caracterisation qualitative du mecanisme de la fissuration en surface et en profondeur. Puis, une caracterisation quantitative a ete realisee pour la determination de la distribution de la largeur de la fissure sur toute sa longueur, ainsi que le pourcentage de sa surface par rapport a la surface totale de l'echantillon. Cette etude a ete realisee par le biais de la technique d'analyse d'image utilisee pour caracteriser la fissuration d'un echantillon d'anode cuite. L'analyse surfacique et en profondeur de cet echantillon a permis de voir clairement la formation des fissures sur une grande partie de la surface analysee. L'autre partie des travaux est basee sur la caracterisation des defauts dans des echantillons d'anodes crues

  8. Effect of an Antibacterial Monomer on the Antibacterial Activity of a Pit-and-Fissure Sealant

    PubMed Central

    Dong, Yan; Zhang, Ling; Sun, Xiang; Liu, Zhengya; Guo, Huihui; Huang, Li; Chen, Jihua

    2016-01-01

    Resin-based pit-and-fissure sealants are often used to form a barrier on the occlusal surface of molars to treat caries lesions; however, bacteria can remain in the pit and fissures without detection, increasing the risk of secondary caries. Sealants with antimicrobial properties or microbial repellent actions might be advantageous. The aim of this study was to assess the inhibitory effect of a 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB)-incorporated sealant against Streptococcus mutans. MAE-DB (4% wt) was incorporated into a commercially available sealant, Eco-S resin-based pit-and-fissure sealant (Vericom Co., Ltd., Korea); a sealant without MAE-DB served as a negative control, and Clinpro™ Sealant (3M™ ESPE™), a fluoride-releasing resin, was used as a commercial control. The effects of the cured sealants and their eluents on the growth of S. mutans were determined according to colony-forming unit counts and metabolic tests. The effects of the cured sealants on the adherence and membrane integrity of S. mutans were investigated using confocal laser-scanning microscopy (CLSM) in conjunction with fluorescent indicators. Compared with the negative control and commercial control, the cured MAE-DB-incorporated pit-and-fissure sealant exhibited a significant inhibitory effect on the growth of S. mutans (P < 0.05), whereas the eluents did not show any detectable antibacterial activity. The commercial control also showed no detectable bactericidal activity. Moreover, the aged experimental material retained its property of contact inhibition of biofilm formation. The fluorescence analysis of CLSM images demonstrated that the cured MAE-DB-incorporated sealant could hamper the adherence of S. mutans and exert a detrimental effect on bacterial membrane integrity. The incorporation of MAE-DB can render a pit-and-fissure sealant with contact antibacterial activity after polymerization via influencing the growth, adherence, and membrane integrity of S

  9. The hydraulic fracturing of geothermal formations

    SciTech Connect

    Naceur, K. Ben; Economides, M.J.; Schlumberger, Dowell

    1988-01-01

    Hydraulic fracturing has been attempted in geothermal formations as a means to stimulate both production and injection wells. Since most geothermal formations contain fissures and on occasion massive natural fissures, the production behavior of the man-made fractures results in certain characteristic trends. A model is offered that allows the presence of a finite or infinite conductivity fracture intercepting a fissured medium. The method is based on a numerical discretization of the formation allowing transient interporosity flow. Type curves for pressure drawdown and cumulative production are given for infinite acting and closed reservoirs. Since most of the fissured formations exhibit a degree of anisotropy, the effects of the orientation of the hydraulic fracture with respect to the fissure planes, and of the ratio between the directional permeabilities are then discussed. Guidelines are offered as to the size of appropriate stimulation treatments based on the observed fissured behavior of the reservoir.

  10. Hawaiian fissure fountains 1: decoding deposits-episode 1 of the 1969-1974 Mauna Ulu eruption

    USGS Publications Warehouse

    Parcheta, C.E.; Houghton, B.F.; Swanson, D.A.

    2012-01-01

    Deposits from episode 1 of the 1969–1974 Mauna Ulu eruption of Kīlauea provide an exceptional opportunity to study processes of low intensity Hawaiian fissure fountains. Episode 1 lava flows passed through dense forest that had little impact on flow dynamics; in contrast, the pattern of spatter preservation was strongly influenced by the forest (through the formation of tree molds) and the preexisting topography. A low, near-continuous spatter rampart is present upwind and upslope, on the north side of the fissure. Most of the pyroclastic products, however, fell downwind to the south of the fissure, but little was preserved due to two processes: (1) incorporation of proximal spatter in rheomorphic lava flows 10–20 m from the vents, and (2) the downslope transport of cooler spatter falling on top of these flows beyond 20 m from vent. The lava flow field itself shows a complex history. Initially, discharge from the fissure exceeded the transport capacity of the southern drainage pathways, and lava ponded dynamically to a maximum height of 4 m for 40–120 min, until fountains began to decline. During declining discharge, lava flowed both southward away from the fissure and increasingly back into the vents. There is a clear “lava-shed” or delineation between where lava drained northwards back into the fissure, and where it continued flowing to the south. The 1969 deposits suggest that care is needed when products of less well-documented eruptions are analyzed, as postdepositional transport of spatter may preclude the formation of classic paired (symmetrical) ramparts.

  11. King's Bowl Pit Crater, Lava Field and Eruptive Fissure, Idaho - A Multipurpose Volcanic Planetary Analog

    NASA Astrophysics Data System (ADS)

    Hughes, S. S.; Garry, B.; Kobs-Nawotniak, S. E.; Sears, D. W. G.; Borg, C.; Elphic, R. C.; Haberle, C. W.; Kobayashi, L.; Lim, D. S. S.; Sears, H.; Skok, J. R.; Heldmann, J. L.

    2014-12-01

    King's Bowl (KB) and its associated eruptive fissure and lava field on the eastern Snake River Plain, is being investigated by the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team as a planetary analog to similar pits on the Moon, Mars and Vesta. The 2,220 ± 100 BP basaltic eruption in Craters of the Moon National Monument and Preserve represents early stages of low shield growth, which was aborted when magma supply was cut off. Compared to mature shields, KB is miniscule, with ~0.02 km3 of lava over ~3 km2, yet the ~6 km long series of fissures, cracks and pits are well-preserved for analog studies of volcanic processes. The termination of eruption was likely related to proximity of the 2,270 ± 50 BP eruption of the much larger Wapi lava field (~5.5 km3 over 325 km2 area) on the same rift. Our investigation extends early work by R. Greeley and colleagues, focusing on imagery, compositional variations, ejecta distribution, dGPS profiles and LiDAR scans of features related to: (1) fissure eruptions - spatter ramparts, cones, feeder dikes, extension cracks; (2) lava lake formation - surface morphology, squeeze-ups, slab pahoehoe lava mounds, lava drain-back, flow lobe overlaps; and (3) phreatic steam blasts - explosion pits, ejecta blankets of ash and blocks. Preliminary results indicate multiple fissure eruptions and growth of a basin-filled lava lake up to ~ 10 m thick with outflow sheet lava flows. Remnant mounds of original lake crust reveal an early high lava lake level, which subsided as much as 5 m as the molten interior drained back into the fissure system. Rapid loss of magma supply led to the collapse of fissure walls allowing groundwater influx that triggered multiple steam blasts along at least 500 m. Early blasts occurred while lake magma pressure was still high enough to produce squeeze-ups when penetrated by ejecta blocks. The King's Bowl pit crater exemplifies processes of a small, but highly energetic

  12. Calcified gallstone fissures: the reversed Mercedes Benz sign.

    PubMed

    Strijk, S P

    1987-01-01

    This article describes the occurrence of an unusual radiating pattern of calcification in the center of large radiolucent gallstones. The radiographic findings are attributed to calcium deposition within the fissures of biliary calculi.

  13. Calcified gallstone fissures: the reversed Mercedes Benz sign.

    PubMed

    Strijk, S P

    1987-01-01

    This article describes the occurrence of an unusual radiating pattern of calcification in the center of large radiolucent gallstones. The radiographic findings are attributed to calcium deposition within the fissures of biliary calculi. PMID:3556975

  14. Differential compaction mechanism for earth fissures near Casa Grande, Arizona.

    USGS Publications Warehouse

    Jachens, R.C.; Holzer, T.L.

    1982-01-01

    Precise gravity measurements indicate that earth fissures or tension cracks caused by ground-water withdrawal within a 10km2 area SE of Casa Grande are associated with relief on the buried interface between the alluvial aquifer and underlying bedrock. These relations suggest that the fissures are forming in response to localized differential compaction caused by localized variations of aquifer-system thickness. -from Authors

  15. Telencephalic Flexure and Malformations of the Lateral Cerebral (Sylvian) Fissure.

    PubMed

    Sarnat, Harvey B; Flores-Sarnat, Laura

    2016-10-01

    After sagittal division of the prosencephalon at 4.5 weeks of gestation, the early fetal cerebral hemisphere bends or rotates posteroventrally from seven weeks of gestation. The posterior pole of the telencephalon thus becomes not the occipital but the temporal lobe as the telencephalic flexure forms the operculum and finally the lateral cerebral or Sylvian fissure. The ventral part is infolded to become the insula. The frontal and temporal lips of the Sylvian fissure, as well as the insula, all derive from the ventral margin of the primitive telencephalon, hence may be influenced by genetic mutations with a ventrodorsal gradient of expression. The telencephalic flexure also contributes to a shift of the hippocampus from a dorsal to a ventral position, the early rostral pole of the hippocampus becoming caudal and dorsal becoming ventral. The occipital horn is the most recent recess of the lateral ventricle, hence most vulnerable to anatomic variations that affect the calcarine fissure. Many major malformations include lack of telencephalic flexure (holoprosencephaly, extreme micrencephaly) or dysplastic Sylvian fissure (lissencephalies, hemimegalencephaly, schizencephaly). Although fissures and sulci are genetically programmed, mechanical forces of growth and volume expansion are proposed to be mainly extrinsic (including ventricles) for fissures and intrinsic for sulci. In fetal hydrocephalus, the telencephalic flexure is less affected because ventricular dilatation occurs later in gestation. Flexures can be detected prenatally by ultrasound and fetal magnetic resonance imaging and should be described neuropathologically in cerebral malformations. PMID:27590993

  16. Modern Perspectives in the Treatment of Chronic Anal Fissures

    PubMed Central

    Bhardwaj, R; Parker, MC

    2007-01-01

    INTRODUCTION Anal fissures are commonly encountered in routine colorectal practice. Developments in the pharmacological understanding of the internal anal sphincter have resulted in more conservative approaches towards treatment. Simple measures are often effective for early fissures. Glyceryl trinitrate is well established as a first-line pharmacological therapy. The roles of diltiazem and botulinum, particularly as rescue therapy, are not well understood. Surgery has a defined role and should not be discounted completely. METHODS Data were obtained from Medline publications citing ‘anal fissure’. Manual cross-referencing of salient articles was conducted. We have sought to highlight various controversies in the management of anal fissures. FINDINGS Acute fissures may heal spontaneously, although simple conservative measures are sufficient. Idiopathic chronic anal fissures need careful evaluation to decide what therapy is suitable. Pharmacological agents such as glyceryl trinitrate (GTN), diltiazem and botulinum toxin have been subjected to most scrutiny. Though practices in the UK vary, GTN or diltiazem would be suitable as first-line therapy with botulinum toxin used as rescue treatment. Sphincterotomy is indicated for unhealed fissures; fissurectomy has been revisited and advancement flaps have a role in patients in whom sphincter division is not suitable. PMID:17688717

  17. Changing patterns of treatment for chronic anal fissure.

    PubMed

    Farouk, R; Gunn, J; Duthie, G S

    1998-05-01

    To assess changing patterns of treatment for chronic anal fissure, a retrospective analysis of treatment for chronic anal fissure within one hospital between January 1990 and December 1996 was undertaken. A total of 221 patients received treatment for a chronic anal fissure in this period, of whom 209 had a surgical procedure. Manual dilatation of the anus was performed in 21 patients (10%) and has not been performed since 1995. Lateral internal sphincterotomy was performed in 183 patients (88%) and continues to be the mainstay of treatment. Five female patients (2%) were identified as having a sphincter defect by anal manometry combined with endoanal ultrasound and were treated by an anal advancement flap. From 1996 onwards, 15 patients (7%) were treated by topical glyceryl trinitrate (GTN) paste as the first line of treatment. Of these patients, nine have experienced healing of their fissure, and three have had relief of pain without healing of the fissure. Three have gone on to have a lateral internal sphincterotomy. Lateral internal sphincterotomy remains the primary form of treatment for chronic anal fissure. GTN cream has increasingly been offered as preliminary treatment over the last 12 months. Perioperative use of endoanal ultrasound allowed identification of patients who may be at high risk of postoperative incontinence from a sphincterotomy. An anal advancement flap has been used as an alternative surgical approach for these patients.

  18. Potential for aquifer compaction, land subsidence, and earth fissures in the Tucson basin, Pima County, Arizona

    USGS Publications Warehouse

    Anderson, S.R.

    1987-01-01

    In 1979 the U.S. Geological Survey, in cooperation with the city of Tucson, began an investigation of aquifer compaction and its effects in the Tucson basin, including the potential hazards of aquifer compaction and subsequent damage to engineered structures, roads, water supply systems, gaslines, and sewage systems. Groundwater is the main source of water for irrigation, public supply, and industry. Pumping has exceeded recharge for several decades, and declines in groundwater levels have occurred in parts of the basin. In places, water level declines have resulted in small amounts of aquifer compaction and land subsidence. Further water level declines in parts of the Tucson basin may result in large amounts of aquifer compaction and land subsidence. Differential land subsidence may, in places, be accompanied by the formation of earth fissures. Aquifer compaction, land subsidence, and earth fissures can damage or affect the functional capability of manmade features. Specifically, aquifer compaction may damage wells, fissures may damage engineered structures, and differential land subsidence may affect structures such as sewers and water-supply systems that are dependent on gravity for their operation. (USGS)

  19. A conceptual model of the hydrological influence of fissures on landslide activity

    NASA Astrophysics Data System (ADS)

    Krzeminska, D. M.; Bogaard, T. A.; van Asch, Th. W. J.; van Beek, L. P. H.

    2012-06-01

    Hydrological processes control the behaviour of many unstable slopes, and their importance for landslide activity is generally accepted. The presence of fissures influences the storage capacity of a soil and affects the infiltration processes of rainfall. The effectiveness of the fissure network depends upon fissure size, their spatial distribution, and connectivity. Moreover, fissure connectivity is a dynamic characteristic, depending on the degree of saturation of the medium. This research aims to investigate the influence of the fissure network on hydrological responses of a landslide. Special attention is given to spatial and temporal variations in fissure connectivity, which makes fissures act both as preferential flow paths for deep infiltration (disconnected fissures) and as lateral groundwater drains (connected fissures). To this end, the hydrological processes that control the exchange of water between the fissure network and the matrix have been included in a spatially distributed hydrological and slope stability model. The ensuing feedbacks in landslide hydrology were explored by running the model with one year of meteorological forcing. The effect of dynamic fissure connectivity was evaluated by comparing simulations with static fissure patterns to simulations in which these patterns change as a function of soil saturation. The results highlight that fissure connectivity and fissure permeability control the water distribution within landslides. Making the fissure connectivity function of soil moisture results in composite behaviour spanning the above end members and introduces stronger seasonality of the hydrological responses.

  20. Identification of pulmonary fissures using a piecewise plane fitting algorithm.

    PubMed

    Gu, Suicheng; Wilson, David; Wang, Zhimin; Bigbee, William L; Siegfried, Jill; Gur, David; Pu, Jiantao

    2012-10-01

    We describe an automated computerized scheme to identify pulmonary fissures depicted in chest computed tomography (CT) examinations from a novel perspective. Whereas CT images can be regarded as a cloud of points, the underlying idea is to search for surface-like structures in the three-dimensional (3D) Euclidean space by using an efficient plane fitting algorithm. The proposed plane fitting operation is performed in a number of small spherical lung sub-volumes to detect small planar patches. Using a simple clustering criterion based on their spatial coherence and surface area, the identified planar patches, assumed to represent fissures, are classified into different types of fissures, namely left oblique, right oblique and right horizontal fissures. The performance of the developed scheme was assessed by comparing with a manually created "reference standard" and the results obtained by a previously developed approach on a dataset of 30 lung CT examinations. The experiments show that the average discrepancy is around 1.0mm in comparison with the reference standard, while the corresponding maximum discrepancy is 20.5mm. In addition, 94% of the fissure voxels identified by the computerized scheme are within 3mm of the fissures in the reference standard. As compared to a previously developed approach, we also found that the newly developed scheme had a smaller discrepancy with the standard reference. In efficiency, it takes approximately 8 min to identify the fissures in a chest CT examination on a typical PC. The developed scheme demonstrates a reasonable performance in terms of accuracy, robustness, and computational efficiency.

  1. Open Fissure Folds record coseismic loading and postseismic stress relaxation

    NASA Astrophysics Data System (ADS)

    Nüchter, Jens-Alexander

    2015-03-01

    Open Fissure Folds hosted by high pressure/low temperature metamorphic rocks of south Evia (Greece) are introduced, their structural and microstructural record is analysed, and a mechanical model is proposed. Open Fissure Folds are preserved as at least two parallel folded quartz-feldspar veins separated by narrow buckled rock columns. The veins originated as tensile cracks that propagated in the middle crust driven by high differential stress. Features diagnostic for Open Fissure Folds indicate that the rock columns represented the layers of high viscosity, and not the veins as consistently reported in many previous studies on folded veins. This record is taken to indicate that buckling of the rock columns initiated after arrest of the fractures and terminated prior to complete vein sealing. Accordingly, mechanical decoupling by open fissures allowed for buckling of the rock columns in response to episodic creep of the host rocks according to stress relaxation, as expected for postseismic deformation in the earthquake cycle. I propose that the parental fractures propagated in response to quasi-instantaneous coseismic loading of the middle crust. Buckling was attributed to transient postseismic creep and stress relaxation. Complete sealing of the veins occurred when stresses were largely relaxed. Each Open Fissure Fold records the stress and strain history of a single earthquake.

  2. Asymmetries in the cerebral dimensions and fissures of the dog.

    PubMed

    Tan, U; Calişkan, S

    1987-02-01

    The surface dimensions and fissures of the right and left cerebral hemispheres were compared in dogs. The right hemisphere was significantly larger in length and height than the left hemisphere; there was no significant difference in the width of the right and left hemispheres. The mean length of the cruciate sulcus did not significantly differ on the right and left sides except individual for asymmetries. The difference in the mean length of the right and left Sylvian fissures was not significant, but the right Sylvian fissure was significantly lower than the left. The base of the right planum temporale tended to be larger than the left. These anatomical asymmetries did not correlate with paw preference. The data are consistent with notion that asymmetrical patterns cannot be a distinctive feature of the human brain.

  3. Cochlear implant electrode array misplaced in Hyrtl's fissure.

    PubMed

    Mouzali, Amina; Ouennoughi, Kheiredidine; Haraoubia, Mohamed-Salah; Zemirli, Omar; Triglia, Jean Michel

    2011-11-01

    Hyrtl's fissure is a cleft that is present in the developing fetal petrous temporal bone and extends from the area inferior to the round window to the meninges of the posterior fossa. Persistent Hyrtl's fissure, due to incomplete ossification, is considered a rare temporal bone malformation, and is a known cause of perilabyrinthine cerebrospinal fluid fistula. Very few cases are reported as being at risk of complication of cochlear implant surgery. Here we report the case of an 8-year-old boy with misplacement of an electrode array in Hyrtl's fissure. The diagnosis was made postoperatively, since cochlear implant failure was suspected from non-auditory responses. Computed tomography (CT) revealed the extracochlear location of the electrode array. We emphasize the role of presurgical imaging CT and magnetic resonance imaging in detecting temporal bone abnormalities, and we discuss the value of intraoperative auditory nerve response telemetry and postoperative radiological evaluation in diagnosing cochlear implant misplacement.

  4. An opening magmatic fissure: structural pattern of its termination

    NASA Astrophysics Data System (ADS)

    Zelenin, Egor A.; Kozhurin, Andrey I.; Pinegina, Tatiana K.; Mikhaylyukova, Polina G.

    2014-05-01

    Volcanic zones of Kamchatka bear two types of active faults and fractures. Faults of the first type are tectonic, so they are long-living with net offset growing with time by repeating movement. Faults of the second type could be termed volcano-tectonic as they couple with or are caused by eruptions and thus move just once. Authors have explored and described a NE-SW-striking fissure on the SW side of Gorely plateau in the South Kamchatka volcanic zone, which conducted magma 200 years ago (Selyangin, Ponomareva, 1999). The fissure depression is filled with basaltic-andesite lava. The 900 meters long southern terminus of the fissure is situated on the hill slope and therefore not overlapped with lava. The fissure ending is an asymmetric graben, deeper at its west side, up to 300 m wide and bounded by two nearly parallel normal faults. The graben floor is gradually deepening to the north, away from the terminus, down to 9-10 m. Bounding faults are perfectly expressed in topography, thus providing a rare opportunity for determination of fissure parameters. Both faults dip at 80-85°, that gives approximately up to 3 m of perpendicular extension and the same thickness of the dyke beneath. Vertical movements on the western and eastern bounding faults were accompanied by horizontal components, left-lateral and right-lateral, respectively. There are also several transverse north-facing scarps breaking the graben floor and not extending beyond its limits. The observed deformations altogether suggests simultaneous sinking of the graben floor and northward compensating movement of masses into the graben. Tectonic landforms we studied illustrate how strain could be compensated at the end of an opening fissure and provide some insight into similar settings at a regional and even global scale.

  5. Engineering a robotic approach to mapping exposed volcanic fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Parness, A.; Mitchell, K. L.

    2014-12-01

    Field geology provides a framework for advanced computer models and theoretical calculations of volcanic systems. Some field terrains, though, are poorly preserved or accessible, making documentation, quantification, and investigation impossible. Over 200 volcanologists at the 2012 Kona Chapman Conference on volcanology agreed that and important step forward in the field over the next 100 years should address the realistic size and shape of volcanic conduits. The 1969 Mauna Ulu eruption of Kīlauea provides a unique opportunity to document volcanic fissure conduits, thus, we have an ideal location to begin addressing this topic and provide data on these geometries. Exposed fissures can be mapped with robotics using machine vision. In order to test the hypothesis that fissures have irregularities with depth that will influence their fluid dynamical behavior, we must first map the fissure vents and shallow conduit to deci- or centimeter scale. We have designed, constructed, and field-tested the first version of a robotic device that will image an exposed volcanic fissure in three dimensions. The design phase included three steps: 1) create the payload harness and protective shell to prevent damage to the electronics and robot, 2) construct a circuit board to have the electronics communicate with a surface-based computer, and 3) prototype wheel shapes that can handle a variety of volcanic rock textures. The robot's mechanical parts were built using 3d printing, milling, casting and laser cutting techniques, and the electronics were assembled from off the shelf components. The testing phase took place at Mauna Ulu, Kīlauea, Hawai'i, from May 5 - 9, 2014. Many valuable design lessons were learned during the week, and the first ever 3D map from inside a volcanic fissure were successfully collected. Three vents had between 25% and 95% of their internal surfaces imaged. A fourth location, a non-eruptive crack (possibly a fault line) had two transects imaging the textures

  6. Dental Pit and Fissure Sealants: Implications for School Health Personnel.

    ERIC Educational Resources Information Center

    McCormack-Brown, K. R.; And Others

    1989-01-01

    To promote good personal hygiene practices in students, school health personnel must be informed about dental pit and fissure sealants and related programs. Adoption and maintenance of such programs may depend on the success of school health personnel in educating administrators and policymakers. (SM)

  7. Innovations in chronic anal fissure treatment: A systematic review

    PubMed Central

    Poh, Aaron; Tan, Kok-Yang; Seow-Choen, Francis

    2010-01-01

    A chronic anal fissure is a common perianal condition. This review aims to evaluate both existing and new therapies in the treatment of chronic fissures. Pharmacological therapies such as glyceryl trinitrate (GTN), Diltiazem ointment and Botulinum toxin provide a relatively non-invasive option, but with higher recurrence rates. Lateral sphincterotomy remains the gold standard for treatment. Anal dilatation has no role in treatment. New therapies include perineal support devices, Gonyautoxin injection, fissurectomy, fissurotomy, sphincterolysis, and flap procedures. Further research is required comparing these new therapies with existing established therapies. This paper recommends initial pharmacological therapy with GTN or Diltiazem ointment with Botulinum toxin as a possible second line pharmacological therapy. Perineal support may offer a new dimension in improving healing rates. Lateral sphincterotomy should be offered if pharmacological therapy fails. New therapies are not suitable as first line treatments, though they can be considered if conventional treatment fails. PMID:21160880

  8. The effect of vegetation on infiltration in shallow soils underlain by fissured bedrock

    NASA Astrophysics Data System (ADS)

    Stothoff, S. A.; Or, D.; Groeneveld, D. P.; Jones, S. B.

    1999-05-01

    Mean annual infiltration above the high-level waste repository proposed to be sited at Yucca Mountain, Nevada, has a large impact on assessments of repository performance. Ongoing investigations of infiltration processes have identified the relatively horizontal caprock environment above portions of the repository as a potentially large source of infiltrating waters, due to shallow, permeable soils above a moderately welded tuff with large soil-filled fissures. The combination of shallow soils and fissured bedrock allows rapid penetration of wetting pulses to below the rooting zone. Plant uptake can strongly reduce net infiltration in arid environments with high water storage capacity, and, despite the low water storage capacity, there is a relatively high vegetation density in this environment. The apparent discrepancy between high vegetation density and low water storage motivates the study of plant-hydrologic interactions in this semiarid environment. Field observations were coupled with plant- and landscape-scale models to provide insight into plant-hydrologic interactions. Several lines of evidence, including: (i) linear plant growth features observed on aerial photographs; (ii) comparisons of plant cover within the fissured environment and comparable environments lacking fissures; and (iii) direct excavations, all suggest that the widely spaced soil-filled fissures are conducive to plant growth even when fissures are buried at soil depths exceeding 30 cm. Results from a mechanistic simulation model for root growth into fissures suggest that the additional (sheltered) plant-available soil water within fissures provides a competitive advantage for plant establishment. Therefore, plants that germinate above a fissure are more likely to survive, in turn developing linear features above fissures. Having established that plants preferentially root within soil-filled fissures in the caprock environment, a set of simulations were performed to examine the hydrologic

  9. Interaction between central volcanoes and fissure swarms along divergent plate boundaries: an example from Askja Volcano, Northern Iceland.

    NASA Astrophysics Data System (ADS)

    Trippanera, Daniele; Ruch, Joel; Acocella, Valerio; Urbani, Stefano; Thordarson, Thor

    2016-04-01

    Central volcanoes located along divergent plate boundaries are typically part of a larger volcanic system that consists of a central edifice and a fissure swarm through which magma propagates and spreads plates apart. Regional normal faults and graben structures develop within the volcanic system, also dissecting portions of the central volcano with ring-faults faults and eruptive fissures related to the caldera structure. Both the fissure swarm and the caldera structure influence the pathway of the ascending magma, however, the influences of the structures on magma propagation and vice versa are not well defined and understood. Here we aim to understand the relationship between the activity of the central volcano structures (e.g. caldera ring faults, radial dykes and cone sheets) and those of the fissure swarm (e.g. regional normal faults, regional dikes). We focus on Askja volcano, located in the Northern Volcanic Zone of Iceland. It is comprised of three nested calderas, largely filled in with subaerial basaltic lava flows and surrounded by a massive hyaloclastite mountain on the Eastern side. Formation of the youngest, the Öskjuvatn caldera, was initiated during the 1874-1876 rifting episode on the Askja system. This major event was followed by several localized radial and circumferential magmatic intrusions taking place along the new-formed caldera ring fault, as well as intruding in the fissure swarm related to the regional tectonics. In order to characterize the influence of the caldera structure on the regional tectonics, we analysed the structural framework of the caldera and direct surroundings using remote sensing (optical imagery and high resolution DEM from TanDEM-X data). Then we made detailed field measurements (500 data) by analysing azimuth, dip, and opening of eruptive fissures, dikes, faults and extension fractures. Both remote sensing and field measurements have been then integrated producing a detailed structural map of Askja. Our results show

  10. Modeling plaque fissuring and dissection during balloon angioplasty intervention.

    PubMed

    Gasser, T Christian; Holzapfel, Gerhard A

    2007-05-01

    Balloon angioplasty intervention is traumatic to arterial tissue. Fracture mechanisms such as plaque fissuring and/or dissection occur and constitute major contributions to the lumen enlargement. However, these types of mechanically-based traumatization of arterial tissue are also contributing factors to both acute procedural complications and chronic restenosis of the treatment site. We propose physical and finite element models, which are generally useable to trace fissuring and/or dissection in atherosclerotic plaques during balloon angioplasty interventions. The arterial wall is described as an anisotropic, heterogeneous, highly deformable, nearly incompressible body, whereas tissue failure is captured by a strong discontinuity kinematics and a novel cohesive zone model. The numerical implementation is based on the partition of unity finite element method and the interface element method. The later is used to link together meshes of the different tissue components. The balloon angioplasty-based failure mechanisms are numerically studied in 3D by means of an atherosclerotic-prone human external iliac artery, with a type V lesion. Image-based 3D geometry is generated and tissue-specific material properties are considered. Numerical results show that in a primary phase the plaque fissures at both shoulders of the fibrous cap and stops at the lamina elastica interna. In a secondary phase, local dissections between the intima and the media develop at the fibrous cap location with the smallest thickness. The predicted results indicate that plaque fissuring and dissection cause localized mechanical trauma, but prevent the main portion of the stenosis from high stress, and hence from continuous tissue damage.

  11. Injectabilite des coulis de ciment dans des milieux fissures

    NASA Astrophysics Data System (ADS)

    Mnif, Thameur

    Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

  12. Identifying the best therapy for chronic anal fissure

    PubMed Central

    Madalinski, Mariusz H

    2011-01-01

    Chronic anal fissure (CAF) is a painful tear or crack which occurs in the anoderm. The optimal algorithm of therapy for CAF is still debated. Lateral internal sphincterotomy (LIS) is a surgical treatment, considered as the ‘gold standard’ therapy for CAF. It relieves CAF symptoms with a high rate of healing. Chemical sphincterotomy (CS) with nitrates, calcium blockers or botulinum toxin (BTX) is safe, with the rapid relief of pain, mild side-effects and no risk of surgery or anesthesia, but is a statistically less effective therapy for CAF than LIS. This article considers if aggressive treatment should only be offered to patients who fail pharmacological sphincterotomy. Aspects of anal fissure etiology, epidemiology and pathophysiology are considered with their meaning for further management of CAF. A molecular model of chemical interdependence significant for the chemistry of CAF healing is examined. Its application may influence the development of optimal therapy for CAF. BTX is currently considered the most effective type of CS and discussion in this article scrutinizes this method specifically. Although the effectiveness of BTX vs. LIS has been discussed, the essential focus of the article concerns identifying the best therapy application for anal fissure. Elements are presented which may help us to predict CAF healing. They provide rationale for the expansion of the CAF therapy algorithm. Ethical and economic factors are also considered in brief. As long as the patient is willing to accept the potential risk of fecal incontinence, we have grounds for the ‘gold standard’ (LIS) as the first-line treatment for CAF. The author concludes that, when the diagnosis of the anal fissure is established, CS should be considered for both ethical and economic reasons. He is convinced that a greater understanding and recognition of benign anal disorders by the GP and a proactive involvement at the point of initial diagnosis would facilitate the consideration of CS at

  13. [The treatment of chronic fissure in ano with nitrate ointment].

    PubMed

    Stassen, L P; Schouten, W R

    1999-01-01

    A chronic anal fissure may be regarded as an ischaemic ulcer. Until recently, its treatment necessitated surgical intervention to lower the tension of the internal sphincter (lateral internal sphincterotomy), or manual dilatation of the anus. A disadvantage of both methods is the risk of permanent sphincter injury resulting in reduced continence. Local application of ointment containing nitroglycerin (glyceryltrinitrate) or isosorbide dinitrate reduces the pressure at rest in the anal canal and increases the anodermal blood circulation. Both ointments in most patients lead to healing of the chronic anal fissure. Nitroglycerin ointment in a prospective, randomized trial brought about better healing than placebo treatment. The advantage of the ointment treatment, the needlessness of sphincterotomy, is particularly important in cases of existing sphincter abnormalities. It has the disadvantage that it takes longer for the fissure pain to abate. The principal side effect is headache. In over 50% of the patients the treatment has to be continued for longer than 6 weeks. Little is known as yet about the risk of recurrence. Before surgical interventions as the treatment of first choice can be definitely replaced by treatment with nitrate ointment the good results of the ointment treatment have to be confirmed. Also, more has to be found out about the risk of recurrence, the optimal duration of the treatment and the choice of the type of nitrate ointment.

  14. The architecture and shallow conduits of Laki-type pyroclastic cones: insights into a basaltic fissure eruption

    NASA Astrophysics Data System (ADS)

    Reynolds, P.; Brown, R. J.; Thordarson, T.; Llewellin, E. W.

    2016-05-01

    Pyroclastic cones built along basaltic fissures provide important volcanological information, but it is often difficult to examine the early-erupted products due to burial by later products. Furthermore, it is rare to see the link between the feeder dyke and overlying cone fully exposed. In this study, we detail the architecture of a hybrid spatter cone, scoria half-cone and feeder dyke that has been dissected to below the pre-eruption surface by glacial floods. The cones were constructed during the 6-8 ka Rauðuborgir-Kvensöðul fissure eruption in North Iceland during Hawaiian- and Strombolian-style activities. Widening of their feeder dyke in the shallow sub-surface to produce an upward flaring morphology was accommodated by country rock removal and elastic host rock deformation. Ballistic calculations and stratigraphic relationships indicate that the scoria half-cone was constructed early in the eruption from the deposits of a lava fountain ~100 m high. A decline in fountain height and the generation of abundant welded deposits resulted in the formation of a nested spatter cone within the scoria half-cone. The cones are similar in structure and size to the hybrid scoria and spatter cones produced during the 15-km3 1783 Laki eruption and serve as a valuable window into the construction of pyroclastic edifices during basaltic fissure eruptions.

  15. The fissure: interlobar collateral ventilation and implications for endoscopic therapy in emphysema

    PubMed Central

    Koster, Theodoor David; Slebos, Dirk-Jan

    2016-01-01

    In patients with severe emphysema, bronchoscopic lung volume reduction using one-way valves is a promising therapeutic option to improve lung function and quality of life. The goal of this treatment is to achieve a complete lobar atelectasis. In a significant proportion of patients, this atelectasis cannot be achieved due to interlobar collateral ventilation. This collateral ventilation is generated through incomplete lobar fissures. Therefore, only patients with complete fissures and no collateral ventilation can be selected for endobronchial therapy with one-way valves. Incomplete fissures are very common and exhibit a great variation in anatomy. The reported prevalence is 17%–85% for the right major fissure, 19%–74% for the left major fissure, and 20%–90% for the minor fissure. There are several methods of measuring or predicting the presence of collateral ventilation, with computed tomography (CT)-fissure analysis and the Chartis measurement being the most important. CT-fissure analysis is an indirect method to measure the completeness of fissures as a surrogate for collateral ventilation. The Chartis system is an endobronchial method to directly measure the presence of collateral ventilation. Both methods have unique value, and the combination of both can accurately predict the treatment response to the bronchoscopic placement of endobronchial valves. This review provides an in-depth view of lung fissure and collateral ventilation to help understand its importance in selecting the appropriate patients for new emphysema treatments and thus avoid useless treatment in unsuitable patients. PMID:27110109

  16. A Review of Cyanoacrylate Liquid Skin Protectant and Its Efficacy on Pedal Fissures

    PubMed Central

    Vlahovic, Tracey C.; Hinton, Elizabeth A.; Chakravarthy, Debashish; Fleck, Cynthia Ann

    2011-01-01

    Introduction Skin fissures are a common dermatologic condition caused by excessive dry skin, numerous systemic diseases, and backless shoe gear. They are defects in skin that fall into the category of damaged, partial-thickness skin wounds, as opposed to full-thickness wounds. Patients with heel fissures are at an increased risk for developing infection, which could cause more severe issues, especially in patients with diabetes and peripheral vascular disease. Methods Five patients from Temple Foot and Ankle Institute, Philadelphia, PA, with a total of 8 heel fissures and 2 hallux fissures, were studied. Patients were dispensed 9 vials of a cyanoacrylate liquid skin protectant (Marathon™, Medline Industries, Inc, Mundelein, IL) to be applied to the fissure every 3 days. Patients returned every 2 weeks for follow-up in clinic. Results The hallux fissures and 4 of the heel fissures went to complete closure after 2 weeks. There was an average decrease of 1.16 cm in length of the heel fissure dimensions after 2 weeks and an average decrease of 1.1 cm in length of the hallux fissures. Conclusion This novel skin protectant proved to be a comfortable, easy, and effective tool in aiding the resolution of pedal skin fissures. PMID:24527155

  17. Enamel fusion using a carbon dioxide laser: A technique for sealing pits and fissures

    SciTech Connect

    Walsh, L.J.; Perham, S.J. )

    1991-05-01

    The well-established enhanced resistance of lased enamel to demineralization is the basis for clinical application of the carbon dioxide laser to caries prevention. This in vitro study examined the effect of focused infrared laser radiation on sound enamel and early pit and fissure caries. Low power levels (2-5 W) induced localized melting and resolidification of enamel with little surface destruction. For sound fissures, fusion of enamel from the lateral walls of the fissure eliminated the fissure space, providing a sealant effect; while in carious fissures, carious enamel was vaporized and adjacent sound enamel fused to partially eliminate the defect. The technique for enamel fusion using CO2 lasers has potential application for sealing pits and fissures and producing physicochemical alterations in enamel which may have preventive benefits.

  18. Phimosis with Preputial Fissures as a Predictor of Undiagnosed Type 2 Diabetes in Adults.

    PubMed

    Huang, Yun-Ching; Huang, Yao-Kuang; Chen, Chih-Shou; Shindel, Alan W; Wu, Ching-Fang; Lin, Jian-Hui; Chiu, Kuo-Hsiung; Yang, Tzu-Hsin; Shi, Chung-Sheng

    2016-03-01

    Diabetes is usually asymptomatic in its early stage. Early diagnosis may improve outcomes by enabling initiation of treatment before end organ damage has progressed. The aim of this study was to determine whether the clinical sign of phimosis with preputial fissures is predictive of type 2 diabetes in patients not previously diagnosed with diabetes. Twenty-eight patients with acquired phimosis and preputial fissures were collected prospectively. Twenty-eight controls with acquired phimosis without preputial fissures were selected. Statistically significant differences were found in body mass index, random plasma glucose, glucosuria and glycosylated haemoglobin levels, but not in age, family history of diabetes, hypertension and classical hyperglycaemic symptoms. Diabetes was confirmed in all 28 patients in the preputial fissures group, but only 2 (7.1%) patients in the non-preputial fissures group (p < 0.0001). In conclusion, phimosis with preputial fissures may be a specific sign of undiagnosed diabetes mellitus. PMID:26349852

  19. Joints, fissures, and voids in rhyolite welded ash-flow tuff at Teton damsite, Idaho

    USGS Publications Warehouse

    Prostka, Harold J.

    1977-01-01

    Several kinds of joints, fissures, and voids are present in densely welded rhyolite ash-flow tuff at Teton damsite. Older fissures and voids probably were formed in the ash-flow sheet during secondary flowage, which probably was caused by differential compaction or settling over irregular topography. The younger, more abundant fissures are mostly steep cooling joints that probably have been opened farther by horizontal tectonic extension and gravitational creep, perhaps aided by lateral stress relief.

  20. Surface anatomy of the pulmonary fissures determined by high-resolution computed tomography.

    PubMed

    Heřmanová, Zuzana; Ctvrtlík, Filip; Heřman, Miroslav

    2012-10-01

    The aim of our study was to describe the surface anatomy of the interlobar fissures using volumetric thin-section high-resolution computed tomography (HRCT). Retrospective assessment of HRCT examinations of 250 patients was performed. The localization of the oblique fissures was marked at three sites: posteriorly at its most superior medial limit, laterally in the midaxillary line, and inferiorly at the junction of the middle and lateral thirds of the hemithorax; posteriorly and laterally, this was to the nearest rib whilst inferiorly the position was described in relation to the diaphragm or chest wall. The localization of the horizontal fissure was marked anteriorly in relation to the nearest rib (or costal cartilage) and posteriorly where it intersected with the oblique fissure (superior, middle, or inferior third). Shapes of the fissures and differences between inspiration and expiration were also documented. Descriptive statistics were used to report the most frequent positions. The most frequent localization of the oblique fissure on the left side was posteriorly at the fourth rib (45%), laterally at the sixth rib (52%), and inferiorly in the anterior third of the hemidiaphragm (60%). The right oblique fissure was located posteriorly at the fifth rib (50%), laterally at the sixth rib (50%), and inferiorly in the anterior third of the hemidiaphragm (71%). The horizontal fissure most commonly originated in the middle third of the oblique fissure (61%) and met the anterior thoracic wall at the level of the fourth rib (51%). The most frequent shape of the left oblique fissure was linear (78%), whereas S-shaped and linear configurations (28% each) were most frequent on the right. No difference was found in the surface markings of the fissures between inspiration and expiration in 90% of cases. The considerable individual variation in the position and shape of the interlobar fissures helps to explain the variable descriptions of their surface anatomy in the

  1. Clinical analysis of molar fissures by Cone-beam tomography.

    PubMed

    Cruvinel, V R N; Azevedo, B C; Gravina, D B L; Toledo, O A; Bezerra, A C B

    2007-01-01

    This study aimed to validate clinical analysis of 20 pediatric dentists on occlusal groove-fossa-system of molar depth comparing to Cone-beam tomography. The 48 sound third molars were visually classified from the shallowest to the deepest. Images were taken from the Accuitomo 3DX. There was a fair correlation between clinical analysis and the tomographic scorings (rs = 0.238; P = 0.103). It was concluded that pediatric dentists were not able to classify the fissures depth by visual analysis correctly. PMID:19161057

  2. Fluoride release and uptake abilities of different fissure sealants

    PubMed Central

    Andenna, Gianluigi; Ceci, Matteo; Beltrami, Riccardo; Colombo, Marco; Cucca, Lucia

    2016-01-01

    Background The long-term capability of resin sealants and glass ionomer cements to release fluoride is associated to a reduction in pit and fissure caries. The regular use of fluoride varnishes/toothpastes can result in the absorption of fluoride into the sealant. The objective of the present study was to assess the fluoride release/uptake capacities of different fissure sealants. Material and Methods Three different fissure sealants (Fuji Triage/GC, Fissurit FX/Voco and Grandio Seal/Voco) were examined. Ten discs of each material were prepared. Each disc was incubated with distilled water and then the solution analyzed for diluted for fluoride concentration, using a combination of fluoride electrode (OrionGP 1 S/N 13824, Orion Research Inc, Boston, MA, USA) connected to an expandable ion analyzer (Orion 720A, Orion Research Inc, Boston, MA, USA). Standard curves between 1 and 100 ppm F- were used to calibrate the electrode. Cumulative fluoride release was measured on days 1, 2, 3, 5, 7, 21, 35 and 49, then two different fluoride varnishes/pastes (Profluorid Varnish/Voco, MI Paste Plus/GC), were applied to the sealants tested, and fluoride release (after reuptake) was measured on days 56, 70 and 84. Results Kruskal Wallis test confirmed significant differences in fluoride release between Fuji Triage/GC and Fissurit FX/Voco and Grandio Seal/Voco from day 1 (P < 0.001). The application of fluoride varnish Profluorid Varnish enhanced the fluoride release for all sealants (P < 0.05). MI Paste Plus enhanced the fluoride release for all sealants except for Fuji Triage/GC (P > 0.05). Conclusions The GIC-based sealant (Fuji Triage/GC) released significantly more fluoride than the resin sealants tested. The exposure to the fluoridated varnish (Profluorid Varnish) significantly recharged the sealants tested more than the CPP-ACPF toothpaste (MI Paste Plus). Key words:Fissure sealants, fluoride release, fluoride uptake, glass ionomer cements. PMID:27398179

  3. A rare case of myeloid sarcoma presenting as anal fissure

    PubMed Central

    VECCHIO, R.; INTAGLIATA, E.; FIUMARA, P.F.; VILLARI, L.; MARCHESE, S.; CACCIOLA, E.

    2015-01-01

    Myeloid sarcoma is a tumor composed of myeloblasts occurring at an extramedullary site. It may develop in patients with acute myeloid leukemia, myeloproliferative or myelodysplastic syndrome, sometimes preceding onset of the systemic disease. Frequent sites of myeloid sarcoma are bones or various soft tissues. Gastrointestinal involvement is very rare. We report a unique case of myeloid sarcoma presenting as a painful anal fissure, in a patient with a history of acute myeloid leukemia. The diagnosis was achieved by a surgical excisional biopsy and immunoistochemical staining. PMID:26712260

  4. Research of features related to land subsidence and ground fissure disasters in the Beijing Plain

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Luo, Y.; Liu, M.; Wang, R.; Wang, H.

    2015-11-01

    This study overviews the development history, current situation, impact, and hazards of land subsidence and ground fissure disasters in the Beijing Plain (BP) and focuses on the disaster distribution and features of disaster-causing mechanisms. Currently, the BP is still in a rapid developmental stage of land subsidence. The development and distribution of land subsidence are affected by various factors including the thickness of Quaternary compressible clay, groundwater overexploitation, and the rapid development of urban construction. The causes of ground fissures in the BP are complex and diverse, with evidence of structure fissures, non-structure fissures, and mixed genesis fissures. Investigations of the Gaoliying ground fissure have shown that this fissure has evidence of fracture activity, with vertical deformation that is more significant than horizontal deformation. Furthermore, this ground fissure has characteristics of inter-annual periodicity and annual jumping. The land subsidence and ground fissures are all under structural control and impact each other, and more severe hazards may be induced under the superimposition of these two types of disasters. Effective measures and suggestions for disaster prevention and control are recommended on the basis of this study.

  5. Automatic pulmonary fissure detection and lobe segmentation in CT chest images

    PubMed Central

    2014-01-01

    Background Multi-detector Computed Tomography has become an invaluable tool for the diagnosis of chronic respiratory diseases. Based on CT images, the automatic algorithm to detect the fissures and divide the lung into five lobes will help regionally quantify, amongst others, the lung density, texture, airway and, blood vessel structures, ventilation and perfusion. Methods Sagittal adaptive fissure scanning based on the sparseness of the vessels and bronchi is employed to localize the potential fissure region. Following a Hessian matrix based line enhancement filter in the coronal slice, the shortest path is determined by means of Uniform Cost Search. Implicit surface fitting based on Radial Basis Functions is used to extract the fissure surface for lobe segmentation. By three implicit fissure surface functions, the lung is divided into five lobes. The proposed algorithm is tested by 14 datasets. The accuracy is evaluated by the mean (±S.D.), root mean square, and the maximum of the shortest Euclidian distance from the manually-defined fissure surface to that extracted by the algorithm. Results Averaged over all datasets, the mean (±S.D.), root mean square, and the maximum of the shortest Euclidian distance are 2.05 ± 1.80, 2.46 and 7.34 mm for the right oblique fissure. The measures are 2.77 ± 2.12, 3.13 and 7.75 mm for the right horizontal fissure, 2.31 ± 1.76, 3.25 and 6.83 mm for the left oblique fissure. The fissure detection works for the data with a small lung nodule nearby the fissure and a small lung subpleural nodule. The volume and emphysema index of each lobe can be calculated. The algorithm is very fast, e.g., to finish the fissure detection and fissure extension for the dataset with 320 slices only takes around 50 seconds. Conclusions The sagittal adaptive fissure scanning can localize the potential fissure regions quickly. After the potential region is enhanced by a Hessian based line enhancement filter, Uniform Cost Search can

  6. Fissure sealants: Knowledge and practice of Yemeni dental practitioners

    PubMed Central

    Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Halboub, Esam Saleh; Al-Soneidar, Walid Ahmed; Tarakji, Bassel; Alsalhani, Anas

    2016-01-01

    Objectives This study was conducted to evaluate Yemeni dental practitioners' knowledge and practices concerning fissure sealants. Materials and Methods: A modified questionnaire consisted of 25-items was distributed to 500 dentists working in Sana'a City. Descriptive statistics and Chi-square/Fisher's exact tests were used for statistical analyses. Results: The response rate was 74%. Most of the respondents were male (61.3%), general practitioners (84.2%), and had <5 years of clinical experience (48.3%). The respondents showed a reasonable level of knowledge about sealants, with the majority (88%) believed that there is strong scientific evidence about fissure sealants effectiveness and around 90% showed a good understanding of sealant placement instructions. On the other hand, respondents showed insufficient knowledge about sealants clinical practice. Conclusion: Although a high proportion of dental practitioners showed adequate knowledge about dental sealant, following guidelines and standardized procedures in clinical practice is lacking. These emphasize the need for regular continuing education courses for dental professional. PMID:27095903

  7. The effect of normal pulsed Nd-YAG laser irradiation on pits and fissures in human teeth.

    PubMed

    Bahar, A; Tagomori, S

    1994-01-01

    The effects of normal pulsed Nd-YAG laser irradiation on the acid resistance of human dental enamel of pits and fissures, the cleaning of the pit and fissure contents and fluoride uptake into deep pits and fissures were examined. The acid resistance of the pit and fissure enamel was evaluated by the amount of dissolved calcium per square millimeter of the surface area. The pit and fissure enamel treated with laser irradiation obtained an acid resistance 30% higher than that of the unlased controls. The cleaning effect of laser irradiation on the pit and fissure contents was compared with chemicomechanical and mechanical methods. The laser irradiation was found to clean the pits and fissures to a greater depth without alterating the shape of pits and fissures, compared with the other two methods. The distribution of calcium, phosphorus and fluoride in the enamel of the pits and fissures was then measured by electron probe microanalyzer. At the entrance and in the deep part of the pits and fissures, the fluoride content of the enamel treated with acidulated phosphate fluoride after laser irradiation was higher than that of the enamel treated with acidulated phosphate fluoride alone. These results thus suggest that Nd-YAG laser irradiation might be effective in increasing the acid resistance of the pit and fissure enamel, while removing the pit and fissure debris contents and increasing the fluoride uptake into the pit and fissure enamel.

  8. Fracture mechanical behavior of red sandstone containing a single fissure and two parallel fissures after exposure to different high temperature treatments

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Jing, Hong-Wen; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong

    2014-12-01

    A detailed understanding of the brittle deformation behavior of sandstone containing pre-existing flaws at elevated temperatures is a key concern in underground engineering. In this research, uniaxial compression tests were performed to evaluate the effect of high temperature treatments (300, 600 or 900 °C) on the strength, deformability and fracture coalescence behavior of a sandstone containing either a single fissure or two parallel fissures. All experiments focused on rectangular prismatic (80 × 160 × 30 mm) specimens of red sandstone. Constant strain rate experiments were performed on either: (1) specimens that contained a single 2 mm-wide fissure or (2) specimens that contained two 2 mm-wide parallel fissures. The specimens containing either one or two fissures were either left at room temperature (i.e., no heat treatment), or heat treated to 300, 600 or 900 °C prior to experimentation. The results demonstrated that, in all cases, the strength and stiffness of red sandstone was increased at 300 °C, before decreasing up to our maximum temperature of 900 °C. However, the peak strain at failure always showed an increase when the temperature was increased. The crack initiation, propagation and coalescence process were monitored during the deformation using both photographic monitoring and acoustic emission (AE) monitoring techniques. The monitoring results showed that the cracking process depended on both the fissure geometry and the heat treatment temperature. The potential mechanisms causing the differences in the mechanical behavior observed with increasing temperature are discussed, as is the influence of the single fissure and the two parallel fissures on the crack evolution process. These results are important and valuable to understand the fracture mechanism of rock engineering in deep underground mining excavations and nuclear waste depositories.

  9. Preserving rice quality: fine mapping and introgressing a fissure resistance locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice (Oryza sativa L.) kernel fissuring is a major concern of both rice producers and millers. Fissures are small cracks in the rice kernels that increase the percentage of breakage among the kernels when they are transported and milled, which decreases the value of processed rice. This study employ...

  10. Baghdad Suchus on Enceladus: Constraints on the Temperature and Width at the Fissure Mouth

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, B. J.; Brown, R. H.; Clark, R. N.; Nicholson, P. D.; Hedman, M. M.; Sotin, C.; Cruikshank, D. P.; Baines, K. H.

    2013-10-01

    A Cassini VIMS spectrum of an active location along Baghdad Sulchus is best fit by a fissure 9 m wide at T=197 K (Goguen et al. 2013, Icarus, accepted). We show that narrower and hotter fissures are unstable due to the exponential increase of the vapor pressure of ice for T greater than 200 K. Ice at 230 K will erode 1 meter/day due to sublimation, so a narrower and warmer fissure will quickly erode to meter widths. The same strong T dependence of the vapor pressure also means that wider fissures at T ~180 K cannot supply to total mass loss rate constraint from Cassini UVIS occultation data. The mass loss rate can be supplied if a significant fraction 190 km) of the total length of the fissures is active as a 9 m wide fissure with T=197 K. The contribution of this hottest component of the fissure emission contributes only a small fraction of the total observed radiated power from the fissures which is dominated by much larger areas at lower T and is best characterized using the CIRS instrument. Copyright 2013 California Institute of Technology.

  11. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  12. 21 CFR 872.3765 - Pit and fissure sealant and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Pit and fissure sealant and conditioner. 872.3765 Section 872.3765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3765 Pit and fissure sealant...

  13. Holocene intracontinental deformation of the northern North China Plain: Evidence of tectonic ground fissures

    NASA Astrophysics Data System (ADS)

    Xu, Liqing; Li, Sanzhong; Cao, Xianzhi; Somerville, I. D.; Suo, Yanhui; Liu, Xin; Dai, Liming; Zhao, Shujuan; Guo, Lingli; Wang, Pengcheng; Cao, Huahua

    2016-04-01

    Following the collecting and analyzing of field data on the geometry and kinematics characteristics of ground fissures in the northern North China Plain (NNCP), this paper shows that en échelon ground fissures or tectonic ground fissures with a length of several meters to tens of kilometers extending along active faults are possibly controlled by underlying active faults. There are two groups of tectonic ground fissures developed in the NNCP. One group consists of ENE-trending "right-stepping" ground fissures, some of which have a component of sinistral motion. The other group is NNE-trending "left-stepping" ground fissures with dextral motion. A large amount of data from trenches, boreholes and seismic exploration reflect that they are active-faulting-related. The NNW-trending regional extensional stress field and the reactivation of pre-existing faults are the major factors controlling ground fissures. Data from the Quaternary sedimentary records, deep incised valleys, the distribution of earthquakes and ground fissures, and our field work show that the Holocene intracontinental deformation of the NNCP is characterized by intense faulting and northwestward tilting, which may be related to a NNW-SSE-oriented tensional stress field in the shallow crust and asthenospheric upwelling in the mantle.

  14. Video monitoring analysis of the dynamics at fissure eruptions

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2016-04-01

    At basaltic eruption often lava fountains occur. The fountains mainly develop at erupting fissures, underlain by a magma-filled dike transporting the magma horizontally and vertically. Understanding of the dynamics of the deep dike and fracture mechanisms are mainly based on geophysical data as well as observations from seismic or geodetic networks. At the surface, however, new methods are needed to allow detailed interpretation on the eruption velocities, interactions between vents and complexities in the magma paths. With video cameras we collected imaging data from different erupting fissures. We find that lava fountaining is often correlated at distinct vents. From the frames of the videos we calculated the height and velocities of fountains as a function of time. Lava fountains often show a pulsating regime, that may change over time. Comparing the fountain height as a function of time of different vents by an time-dependent cross-correlation, we find a time lag between the pulses at adjacent vents. From this we derive an apparent velocity of temporal separation between vents, associated with the fountaining activity based on the calculated time lag and the vent distances. Although the correlation system can change episodically and sporadically, both the frequency of the fountains and eruption and the rest time between single fountains remain remarkably similar for adjacent lava fountains imply a controlling process in the magma feeder system itself. We present and compare our method for the Kamoamoa eruption 2011 (Hawaii) and the Holuhraun eruption 2014/2015 (Iceland). Both sites show a significant time shift between the single pulses of adjacent vents. We compare our velocities determined by this time shift to the assumed magma flow velocity in the dike as determined by independent models. Therefore we conjecture that the time shift of venting activity may allow to estimate the dynamics of magma and fluid migration at depth, as well as to identify the

  15. Pleistocene microvertebrates from fissure-fillings in Thailand

    NASA Astrophysics Data System (ADS)

    Chaimanee, Yaowalak; Jaeger, Jean-Jacques; Suteethorn, Varavudh

    Microvertebrates (and among them specially, rodents) have contributed to the elaboration of precise biochronological time scales and to the reconstitution of Pleistocene paleoenvironments in several parts of the world (North America, Africa, Europe and Japan). They have been demonstrated to be highly sensitive to climatic changes since they are very sensitive to vegetation changes. Up to now, no data is available for Southeast Asia and very few information is available concerning the nature of climatic changes which affected that part of the tropical world during the Pleistocene. In the past few years, we have discovered several fissure fillings in Thailand yielding numerous remains of microvertebrates which have been extracted by dissolution in acetic acid solution. These deposits are the result of the feeding activity of predators, like owls or diurnal raptors, whose pellets are accumulated in caves or fissures. Eleven localities, located in Central (2), Eastern (1), Western (2) and Peninsular Thailand (6) have been investigated so far. Several rodent species, belonging to 9 genera of Murinae (rats and mice) and 9 genera of Sciuridae (squirrels) have been identified in these localities. The most important differences with the extant representatives often concern the size of the teeth of these fossil species. The meaning of these size differences is not yet clearly understood since they can be attributed either to significant time differences between localities (microevolution) or as the result of size variations related to climatic changes (clinical variations). More data will have to be collected to calibrate the temporal frame. Already, important modification of the geographic distribution of some species have been discovered which testify that during the Pleistocene, significative climatic changes have affected Southeast Asia. For example, Exilisciurus, a squirrel which is presently restricted to Borneo has been recognized in Peninsular Thailand. Also, Iomys

  16. Fissure sealant materials: Wear resistance of flowable composite resins

    PubMed Central

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  17. Fissure sealant materials: Wear resistance of flowable composite resins

    PubMed Central

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm2 and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm2of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics. PMID:27651887

  18. Fissure sealant materials: Wear resistance of flowable composite resins.

    PubMed

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics. PMID:27651887

  19. Fissure sealant materials: Wear resistance of flowable composite resins.

    PubMed

    Asefi, Sohrab; Eskandarion, Solmaz; Hamidiaval, Shadi

    2016-01-01

    Background. Wear resistance of pit and fissure sealant materials can influence their retention. Wear characteristics of sealant materials may determine scheduling of check-up visits. The aim of this study was to compare wear resistance of two flowable composite resins with that of posterior composite resin materials. Methods. Thirty-five disk-shaped specimens were prepared in 5 groups, including two flowable composite resins (Estelite Flow Quick and Estelite Flow Quick High Flow), Filtek P90 and Filtek P60 and Tetric N-Ceram. The disk-shaped samples were prepared in 25-mm diameter by packing them into a two-piece aluminum mold and then light-cured. All the specimens were polished for 1minute using 600-grit sand paper. The samples were stored in distilled water at room temperature for 1 week and then worn by two-body abrasion test using "pin-on-disk" method (with distilled water under a 15-Nload at 0.05 m/s, for a distance of 100 meter with Steatite ceramic balls antagonists). A Profilometer was used for evaluating the surface wear. Data were analyzed with the one-way ANOVA. Results. Estelite Flow Quick exhibited 2708.9 ± 578.1 μm(2) and Estelite Flow Quick High Flow exhibited 3206 ± 2445.1 μm(2)of wear but there were no significant differences between the groups. They demonstrated similar wear properties. Conclusion. Estelite flowable composite resins have wear resistance similar to nano- and micro-filled and micro-hybrid composite resins. Therefore, they can be recommended as pit and fissure sealant materials in the posterior region with appropriate mechanical characteristics.

  20. Discrete element modeling on the crack evolution behavior of brittle sandstone containing three fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Huang, Yan-Hua; Ranjith, P. G.; Jiao, Yu-Yong; Ji, Jian

    2015-12-01

    Based on experimental results of brittle, intact sandstone under uniaxial compression, the micro-parameters were firstly confirmed by adopting particle flow code (PFC^{2D}). Then, the validation of the simulated models were cross checked with the experimental results of brittle sandstone containing three parallel fissures under uniaxial compression. The simulated results agreed very well with the experimental results, including the peak strength, peak axial strain, and ultimate failure mode. Using the same micro-parameters, the numerical models containing a new geometry of three fissures are constructed to investigate the fissure angle on the fracture mechanical behavior of brittle sandstone under uniaxial compression. The strength and deformation parameters of brittle sandstone containing new three fissures are dependent to the fissure angle. With the increase of the fissure angle, the elastic modulus, the crack damage threshold, and the peak strength of brittle sandstone containing three fissures firstly increase and secondly decrease. But the peak axial strain is nonlinearly related to the fissure angle. In the entire process of deformation, the crack initiation and propagation behavior of brittle sandstone containing three fissures under uniaxial compression are investigated with respect to the fissure angle. Six different crack coalescence modes are identified for brittle sandstone containing three fissures under uniaxial compression. The influence of the fissure angle on the length of crack propagation and crack coalescence stress is evaluated. These investigated conclusions are very important for ensuring the stability and safety of rock engineering with intermittent structures.

  1. Infrasound from the 2007 fissure eruptions of Kīlauea Volcano, Hawai'i

    USGS Publications Warehouse

    Fee, D.; Garces, M.; Orr, T.; Poland, M.

    2011-01-01

    Varied acoustic signals were recorded at Kīlauea Volcano in mid-2007, coincident with dramatic changes in the volcano's activity. Prior to this time period, Pu'u 'Ō'ō crater produced near-continuous infrasonic tremor and was the primary source of degassing and lava effusion at Kīlauea. Collapse and draining of Pu'u 'Ō'ō crater in mid-June produced impulsive infrasonic signals and fluctuations in infrasonic tremor. Fissure eruptions on 19 June and 21 July were clearly located spatially and temporally using infrasound arrays. The 19 June eruption from a fissure approximately mid-way between Kīlauea's summit and Pu'u 'O'o produced infrasound for ~30 minutes-the only observed geophysical signal associated with the fissure opening. The infrasound signal from the 21 July eruption just east of Pu'u 'Ō'ō shows a clear azimuthal progression over time, indicative of fissure propagation over 12.9 hours. The total fissure propagation rate is relatively slow at 164 m/hr, although the fissure system ruptured discontinuously. Individual fissure rupture times are estimated using the acoustic data combined with visual observations.

  2. Are pit and fissure sealants needed in children with a higher caries risk?

    PubMed

    Berger, Susanne; Goddon, Inka; Chen, Chih-Mei; Senkel, Helga; Hickel, Reinhard; Stösser, Lutz; Heinrich-Weltzien, Roswitha; Kühnisch, Jan

    2010-10-01

    The aim of this cross-sectional study was to analyse the preventive need of pit and fissure sealants (PFS) in a German population with a relatively high caries risk. The study involved 311 8- to 12-year-old children from the Ennepe-Ruhr District in North Rhine-Westphalia, Germany. Caries experience was scored according to WHO (1997) and ICDAS II criteria. PFS were assessed as intact or partially lost. The mean DFS values amounted to 0.5 for occlusal fissures, 0.2 for palatal/buccal pits and 0.3 for the remaining teeth. Non-cavitated caries lesions were recorded in average on 1.8 occlusal fissures and 1.5 palatal/buccal pits. Sealants were registered on 1.4 occlusal fissures and 0.4 palatal/buccal pits. The descriptive data and the adjusted Poisson regression models revealed that children with at least one fissure sealant are less likely to have decayed fissures or fissures with non-cavitated lesions on their permanent molars. Therefore, PFS are needed and indicated in caries-risk children.

  3. Automatic segmentation of pulmonary fissures in computed tomography images using 3D surface features.

    PubMed

    Yu, Mali; Liu, Hong; Gong, Jianping; Jin, Renchao; Han, Ping; Song, Enmin

    2014-02-01

    Pulmonary interlobar fissures are important anatomic structures in human lungs and are useful in locating and classifying lung abnormalities. Automatic segmentation of fissures is a difficult task because of their low contrast and large variability. We developed a fully automatic training-free approach for fissure segmentation based on the local bending degree (LBD) and the maximum bending index (MBI). The LBD is determined by the angle between the eigenvectors of two Hessian matrices for a pair of adjacent voxels. It is used to construct a constraint to extract the candidate surfaces in three-dimensional (3D) space. The MBI is a measure to discriminate cylindrical surfaces from planar surfaces in 3D space. Our approach for segmenting fissures consists of five steps, including lung segmentation, plane-like structure enhancement, surface extraction with LBD, initial fissure identification with MBI, and fissure extension based on local plane fitting. When applying our approach to 15 chest computed tomography (CT) scans, the mean values of the positive predictive value, the sensitivity, the root-mean square (RMS) distance, and the maximal RMS are 91 %, 88 %, 1.01 ± 0.99 mm, and 11.56 mm, respectively, which suggests that our algorithm can efficiently segment fissures in chest CT scans.

  4. Cassini VIMS Spectra of the Thermal Emission from Hot Spots Along Enceladus South Pole Fissures

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, Bonnie J.; Cassini VIMS Team

    2016-10-01

    Most of the south pole fissure region has not been directly illuminated by sunlight since the sub-solar point moved into the northern hemisphere in 2009, thereby eliminating the background of reflected sunlight at VIMS wavelengths and making the fissure thermal emission readily measureable. Since then, VIMS has measured spectra of at least 11 hot spots along the fissures. Most of these measurements were acquired in ride-along mode with CIRS as the prime instrument. During at least 2 encounters, VIMS and CIRS acquired simultaneous or near-simultaneous spectra of the same fissure location. VIMS spectra include multiple hot spots along Damascus, Baghdad, Cairo, and a likely hot spot on Alexandria.All of the VIMS spectra examined to date are consistent with this scenario of a self-regulating fissure maximum T~200 K with brighter VIMS emissions corresponding to fissures up to ~20 m wide. Emission from the warm fissure interior walls dominate the VIMS spectra with <15% contributed by conductive heating of the adjacent terrain at VIMS wavelengths.CIRS spectra report slightly cooler T's due to CIRS increased sensitivity to lower T emission at longer wavelengths and averaging over contributions from both the hottest and cooler areas. Combined analysis of the CIRS and VIMS spectra spanning 3 to 500 micron wavelengths promises to reveal the distribution of [T, area] near the fissures that cannot be spatially resolved. This [T, area] distribution holds the key to understanding how heat is transferred to the surface within a few 100 m of the fissures.The VIMS-detected emission is concentrated in localized hot spots along the fissures and does not seem to be distributed continuously along them. CIRS spectra suggest a more continuous distribution of the emission along the fissure length. Jets locations also are distributed along the fissure length and it appears that the VIMS-detected hot spots in general correlate with jet locations, but not all of the jet locations have been

  5. Painless Ulcers and Fissures of Toes: Hereditary Sensory Neuropathy, Not Leprosy

    PubMed Central

    Rao, Angoori Gnaneshwar

    2016-01-01

    Hereditary sensory neuropathies (HSN) are rare genetically determined neuropathies. They often manifest as painless injuries in children. We present HSN in a 5-year-old boy who presented with recurrent fissuring and ulceration involving both great toes. PMID:26955138

  6. Putative fissure-resistance QTLs mapped to chromosomes 1 and 8 based on allelic frequency differences observed between fissure-resistant and fissure-susceptible progeny from two segregating populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Whole rice kernels have two to three times more market value than broken, which means that any reduction in milling yield results in financial losses for both rice producers and millers. One of the primary causes of rice breakage during milling is fissuring of the rice before it even enters the mil...

  7. Radar Observations of Fissure-fed Basaltic Lava Flows, Craters of the Moon, Idaho

    NASA Technical Reports Server (NTRS)

    Martel, L.; Greeley, R.

    1985-01-01

    Changes in surface roughness of lava flows, estimated from dual polarization, synthetic aperture, X and L band side-looking airborne radar images, were tested as a means of locating fissure vent areas. If lava textures proess from smooth, near-vent shelly pahoehoe to hummocky pahoehoe to aa with distance from fissure vents, then radr images of the lava flows would show a progression from dark to brighter tones due to the flows' increasing radar back-scatter.

  8. Monitoring on Xi'an ground fissures deformation with TerraSAR-X data

    USGS Publications Warehouse

    Zhao, C.; Zhang, Q.; Zhu, W.; Lu, Zhiming

    2012-01-01

    Owing to the fine resolution of TerraSAR-X data provided since 2007, this paper applied 6 TerraSAR data (strip mode) during 3rd Dec. 2009 to 23rd Mar. 2010 to detect and monitor the active fissures over Xi'an region. Three themes have been designed for high precision detection and monitoring of Xi'an-Chang'an fissures, as small baseline subsets (SBAS) to test the atmospheric effects of differential interferograms pair stepwise, 2-pass differential interferogram with very short baseline perpendicular to generate the whole deformation map with 44 days interval, and finally, corner reflector (CR) technique was used to closely monitor the relative deformation time series between two CRs settled crossing two ground fissures. Results showed that TerraSAR data are a good choice for small-scale ground fissures detection and monitoring, while special considerations should be taken for their great temporal and baseline decorrelation. Secondly, ground fissures in Xi'an were mostly detected at the joint section of stable and deformable regions. Lastly, CR-InSAR had potential ability to monitor relative deformation crossing fissures with millimeter precision.

  9. Fracturing and earthquake activity within the Prestahnúkur fissure swarm in the Western Volcanic Rift Zone of Iceland

    NASA Astrophysics Data System (ADS)

    Hjartardóttir, Ásta Rut; Hjaltadóttir, Sigurlaug; Einarsson, Páll; Vogfjörd, Kristín.; Muñoz-Cobo Belart, Joaquín.

    2015-12-01

    The Prestahnúkur fissure swarm is located within the ultraslowly spreading Western Volcanic Zone in Iceland. The fissure swarm is characterized by normal faults, open fractures, and evidence of subglacial fissure eruptions (tindars). In this study, fractures and faults within the Prestahnúkur fissure swarm were mapped in detail from aerial photographs to determine the extent and activity of the fissure swarm. Earthquakes during the last ~23 years were relocated to map the subsurface fault planes that they delineate. The Prestahnúkur fissure swarm is 40-80 km long and up to ~20 km wide. Most of the areas of the fissure swarm have been glacially eroded, although a part of it is covered by postglacial lava flows. The fissure swarm includes numerous faults with tens of meters vertical offset within the older glacially eroded part, whereas open fractures are found within postglacial lava flows. Comparison of relocated earthquakes and surface fractures indicates that some of the surface fractures have been activated at depth during the last ~23 years, although no dike intrusions have been ongoing. The existence of tindars nevertheless indicates that dike intrusions and rifting events do occur within the Prestahnúkur fissure swarm. The low-fracture density within postglacial lava flows and low density of postglacial eruptive fissures indicate that rifting episodes occur less often than in the faster spreading Northern Volcanic Zone.

  10. Comparison of Various Concentrations of Tricalcium Phosphate Nanoparticles on Mechanical Properties and Remineralization of Fissure Sealants

    PubMed Central

    Tavassoli-Hojjati, Sara; Atai, Mohammad; Haghgoo, Roza; Rahimian-Imam, Sara; Kameli, Somayeh; Ahmaian-Babaki, Fatemeh; Hamzeh, Faezeh; Ahmadyar, Maryam

    2014-01-01

    Objective: The aim of this study was to investigate the mechanical properties (flexural strength, micro-shear bond strength) and remineralizing potential of fissure sealants by adding various concentrations of β-tricalcium phosphate nanoparticles. Materials and Methods: This in-vitro study consisted of five experimental groups containing prepared nano-fisssure sealants (1–5 wt.% β-TCP nanoparticles) and two control groups containing a prepared and a commercial fissure sealant. Flexural/micro-shear bond strength values were measured using Zwick test machine. Cavities on sixty healthy premolar teeth were filled with the fissure sealants containing 0–5 wt.% of nano β-TCP. The samples were assessed for remineralization under scanning electron microscopy (SEM) and EDAX. Kolmogorov-Smirnov test, One-way ANOVA and Tukey’s Post Hoc analysis/HSD were used to analyze the data. Results: There was no significant difference between the flexural strengths/elastic modulus of the 0–5 wt.% nano β-TCP groups (p>0.05). The average flexural strength/elastic modulus of the prepared fissure sealant group (0%) was significantly higher than the commercial fissure sealant group (Clinpro) (p<0.05). There was no significant difference between micro-shear bond strengths of the experimental groups (1–5 wt.%), and between the commercial and the prepared (0%) fissure sealant groups (p>0.05). Examining the samples under SEM showed a significant increase in thickness of the intermediate layer with increasing concentrations of β-TCP nanoparticles (p<0.05). Conclusion: Addition of 1–5 wt.% β-TCP nanoparticles to the fissure sealants significantly increased the remineralization potential without affecting the mechanical properties. PMID:25584048

  11. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study

    PubMed Central

    Reddy, V. Rajashekar; Chowdhary, Nagalakshmi; Mukunda, K. S.; Kiran, N. K.; Kavyarani, B. S.; Pradeep, M. C.

    2015-01-01

    Background and Objectives: The most caries-susceptible period of a permanent first molar tooth is the eruption phase, during which the enamel is not fully matured and it is usually difficult for the child to clean the erupting tooth surfaces. Sealing occlusal pits and fissures with resin-based pit and fissure sealants is a proven method to prevent occlusal caries. The difference in the viscosity of the sealants differs in the penetration into pit and fissures and abrasive wear resistance property due to the addition of filler particles. The present study was conducted to evaluate and compare the retention of the resin-based filled (Helioseal F, Ivoclar Vivadent) and unfilled (Clinpro, 3M ESPE) pit and fissure sealants, which is important for their effectiveness. Materials and Methods: Fifty-six children between the age group of 6 and 9 years, with all four newly erupted permanent first molars were selected. Sealants were applied randomly using split mouth design technique on permanent first molars. Evaluation of sealant retention was performed at regular intervals over 12 months, using Simonsen's criteria at 2nd, 4th, 6th, 8th, 10th and 12th month. The results were subjected to statistical analysis. Results: At the end of our study period (12th month), 53.57% showed complete retention, 37.50% showed partial retention, and 8.83% showed complete missing of resin-based filled (Helioseal F) pit and fissure sealant. And, 64.29% showed complete retention, 32.14% showed partial retention, and 3.57% showed complete missing of resin-based unfilled (Clinpro) pit and fissure sealant. This difference in retention rates between filled and unfilled pit and fissure sealants was not statistically significant. Conclusion: The difference in retention rates between Helioseal F and Clinpro was not statistically significant, but Clinpro (unfilled) sealant showed slightly higher retention rates and clinically better performance than Helioseal F (filled). PMID:25821368

  12. Mineralized deposits in pulps of incompletely developed permanent monkey incisors after pulpotomy with tungsten carbide fissure burs.

    PubMed

    Heide, S; Koppang, H S

    1994-06-01

    The exposed pulp of incompletely developed permanent incisors of nine monkeys were treated with partial pulpotomy with tungsten carbide fissure burs on an air turbine equipment. The pulps were capped with calcium hydroxide (Dycal) followed by insertion of conventional amalgam. The results were studied by conventional light microscopy after 1 and 6 months. Rod-like mineralized pulpal deposits were seen in five of the nine animals, in 9 out of 67 teeth, evenly distributed at the two observation times. Also the lengths of the deposits appeared similar, while the thickness had increased markedly after 6 months. After 1 month the presence of a central vessel lumen was observed in the deposits. The results seemed to indicate that the mechanism of formation was an initial pathologic mineralization of the vessel wall, and a growth of the deposits by the elaboration of fibrous, atubular dentin on to the outside of this wall.

  13. Geometry of the September 1971 eruptive fissure at Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Dvorak, J.J.

    1990-01-01

    A three-dimensional model has been used to estimate the location and dimensions of the eruptive fissure for the 24-29 September 1971 eruption along the southwest rift zone of Kilauea volcano, Hawaii. The model is an inclined rectangular sheet embedded in an elastic half-space with constant displacement on the plane of the sheet. The set of "best" model parameters suggests that the sheet is vertical, extends from a depth of about 2 km to the surface, and has a length of about 14 km. Because this sheet intersects the surface where eruptive vents and extensive ground cracking formed during the eruption, this sheet probably represents the conduit for erupted lava. The amount of displacement perpendicular to the sheet is about 1.9 m, in the middle range of values measured for the amount of opening across the September 1971 eruptive fissure. The thickness of the eruptive fissure associated with the January 1983 east rift zone eruption was determined in an earlier paper to be 3.6 m, about twice the thickness determined here for the September 1971 eruption. Because the lengths (12 km for 1983 and 14 km for 1971) and heights (about 2 km) of the sheet models derived for the January 1983 and September 1971 rift zone eruptions are nearly identical, the greater thickness for the January 1983 eruptive fissure implies that the magma pressure was about a factor of two greater to form the January 1983 eruptive fissure. Because the September 1971 and January 1983 eruptive fissures extent to depths of only a few kilometers, the region of greatest compressive stress produced along the volcano's flank by either of these eruptive fissures would also be within a few kilometers of the surface. Previous work has shown that rift eruptions and intrusions contribute to the buildup of compressive stress along Kilauea's south flank and that this buildup is released by increased seismicity along the south flank. Because south flank earthquakes occur at significantly greater depths, i.e., from 5

  14. In vitro evaluation of shear bond strength and microleakage of different pit and fissure sealants

    PubMed Central

    Babaji, Prashant; Vaid, Shivali; Deep, S.; Mishra, Samvit; Srivastava, Madhulika; Manjooran, Thomas

    2016-01-01

    Aim and Objectives: Fissure caries is most common in children due to deep pit and fissures. Pit and fissure areas on the occlusal surface of the teeth make them susceptible to dental caries, which need to be prevented or restored. Fissures sealant reduces the risk of occlusal caries. The present study was done to evaluate microleakage and shear bond strength of various fissure sealants. Materials and Methods: Thirty-six extracted molars were randomly allocated equally (n = 12) into three groups with three different sealants to evaluate shear bond strength and microleakage at sealant space. The shear bond strengths was evaluated with one-way analysis of variance and microleakage by Kruskal-Wallis nonparametric test using the Statistical Package for the Social Sciences version 18.0 (Chicago: SPSS Inc, 2009). Results: Tetric flow (16.8 MPa) recorded the highest shear bond strength and the difference was statistically significant with enamel loc (12.8 MPa). There was no statistically significant difference in relation to microleakage (P > 0.05) in the tested groups. Conclusions: Tetric flow recorded the highest shear bond strength and the difference was statistically significant with enamel loc. However, there was no statistically significant difference among the groups regarding microleakage.

  15. In vitro evaluation of shear bond strength and microleakage of different pit and fissure sealants

    PubMed Central

    Babaji, Prashant; Vaid, Shivali; Deep, S.; Mishra, Samvit; Srivastava, Madhulika; Manjooran, Thomas

    2016-01-01

    Aim and Objectives: Fissure caries is most common in children due to deep pit and fissures. Pit and fissure areas on the occlusal surface of the teeth make them susceptible to dental caries, which need to be prevented or restored. Fissures sealant reduces the risk of occlusal caries. The present study was done to evaluate microleakage and shear bond strength of various fissure sealants. Materials and Methods: Thirty-six extracted molars were randomly allocated equally (n = 12) into three groups with three different sealants to evaluate shear bond strength and microleakage at sealant space. The shear bond strengths was evaluated with one-way analysis of variance and microleakage by Kruskal-Wallis nonparametric test using the Statistical Package for the Social Sciences version 18.0 (Chicago: SPSS Inc, 2009). Results: Tetric flow (16.8 MPa) recorded the highest shear bond strength and the difference was statistically significant with enamel loc (12.8 MPa). There was no statistically significant difference in relation to microleakage (P > 0.05) in the tested groups. Conclusions: Tetric flow recorded the highest shear bond strength and the difference was statistically significant with enamel loc. However, there was no statistically significant difference among the groups regarding microleakage. PMID:27652241

  16. Maps showing water-level declines, land subsidence, and earth fissures in south-central Arizona

    USGS Publications Warehouse

    Laney, R.L.; Raymond, R.H.; Winikka, C.C.

    1978-01-01

    From 1915 to 1975, more than 109 million acre-feet of ground water was withdrawn from about 4,500 square miles in Pinal and Maricopa Counties in south-central Arizona. The volume of water withdrawn greatly exceeds the volume of natural recharge, and water levels have been declining since 1923. As a result of the water-level declines, the land surface has subsided, the alluvial deposits have been subjected to stress, and earth fissures have developed. Land subsidence and earth fissures have damaged public and private properties. Subsidence and fissures will continue to occur as long as ground water is being mined and water levels continue to decline. As urban development expands, land subsidence and earth fissures will have an increasing socioeconomic impact. Information on maps includes change in water levels, measurements of land subsidence, and location of earth fissures. A section showing land subsidence between Casa Grande and the Picacho Peak Interchange also is included. Scale 1:250,000. (Woodard-USGS)

  17. An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Hua; Yang, Sheng-Qi; Tian, Wen-Ling; Zeng, Wei; Yu, Li-Yuan

    2016-06-01

    Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel fissures. In the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures (a horizontal fissure and an inclined fissure) were created by inserting steel during molding the model specimen. Then all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servo-controlled testing system. The peak strength and Young's modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0° to 75°. In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation process. Moreover, acoustic emission (AE) monitoring technique was also used to obtain the AE evolution characteristic of pre-fissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up: when a new crack was initiated or a crack coalescence occurred, the corresponding axial stress dropped in the axial stress-time curve and a big AE event could be observed simultaneously. Finally, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures.

  18. The effect of CT technical factors on quantification of lung fissure integrity

    NASA Astrophysics Data System (ADS)

    Chong, D.; Brown, M. S.; Ochs, R.; Abtin, F.; Brown, M.; Ordookhani, A.; Shaw, G.; Kim, H. J.; Gjertson, D.; Goldin, J. G.

    2009-02-01

    A new emphysema treatment uses endobronchial valves to perform lobar volume reduction. The degree of fissure completeness may predict treatment efficacy. This study investigated the behavior of a semiautomated algorithm for quantifying lung fissure integrity in CT with respect to reconstruction kernel and dose. Raw CT data was obtained for six asymptomatic patients from a high-risk population for lung cancer. The patients were scanned on either a Siemens Sensation 16 or 64, using a low-dose protocol of 120 kVp, 25 mAs. Images were reconstructed using kernels ranging from smooth to sharp (B10f, B30f, B50f, B70f). Research software was used to simulate an even lower-dose acquisition of 15 mAs, and images were generated at the same kernels resulting in 8 series per patient. The left major fissure was manually contoured axially at regular intervals, yielding 37 contours across all patients. These contours were read into an image analysis and pattern classification system which computed a Fissure Integrity Score (FIS) for each kernel and dose. FIS values were analyzed using a mixed-effects model with kernel and dose as fixed effects and patient as random effect to test for difference due to kernel and dose. Analysis revealed no difference in FIS between the smooth kernels (B10f, B30f) nor between sharp kernels (B50f, B70f), but there was a significant difference between the sharp and smooth groups (p = 0.020). There was no significant difference in FIS between the two low-dose reconstructions (p = 0.882). Using a cutoff of 90%, the number of incomplete fissures increased from 5 to 10 when the imaging protocol changed from B50f to B30f. Reconstruction kernel has a significant effect on quantification of fissure integrity in CT. This has potential implications when selecting patients for endobronchial valve therapy.

  19. Conversion degree, microhardness, microleakage and fluoride release of different fissure sealants.

    PubMed

    Kuşgöz, Adem; Tüzüner, Tamer; Ulker, Mustafa; Kemer, Bariş; Saray, Onur

    2010-11-01

    The purpose of this study was to determine the degree of conversion (DC), microhardness, microleakage and fluoride release of a nano-filled resin based fissure sealant (Grandio Seal, GS) and compare it with an un-filled resin based fissure sealant (Clinpro, CL) and a glass-ionomer based fissure sealant (Fuji Triage, FT). Disk shaped specimens were prepared from tested fissure sealants to determine the DC, Vicker hardness (VHN) and fluoride release (FR). The DC and VHN of each material was evaluated after 24 h. The cumulative fluoride concentrations were evaluated at 1 h, 6 h, 12 h, 1, 7, 15 and 30 days. For microleakage evaluation, fissure sealants were applied to the etched and dried enamel surfaces of sound third molar teeth according to the manufacturer's instructions (n=10). After the thermocycling and mechanical loading procedures, microleakage assessments were carried out. Data were analyzed using one-way ANOVA followed by a post hoc Tukey test, the Kruskal Wallis and Mann-Whitney U test (p<0.05). Results revealed differences regarding DC between all groups: FT (89%) > GS (55.02%) > CL (%51.10) (p<0.05). The VHN values were significantly different among all groups in the following order: GS > FT > CL (p<0.05). FT exhibited significantly higher microleakage scores compared to the CL and GS sealants (p<0.05). The FR of FT was significantly greater than CL and GS (p<0.05). Nano-filled resin based sealant can be used as an alternative to other fissure sealant materials because of its superior hardness results and feasible sealing ability.

  20. A robotic approach to mapping post-eruptive volcanic fissure conduits

    NASA Astrophysics Data System (ADS)

    Parcheta, Carolyn E.; Pavlov, Catherine A.; Wiltsie, Nicholas; Carpenter, Kalind C.; Nash, Jeremy; Parness, Aaron; Mitchell, Karl L.

    2016-06-01

    VolcanoBot was developed to map volcanic vents and their underlying conduit systems, which are rarely preserved and generally inaccessible to human exploration. It uses a PrimeSense Carmine 1.09 sensor for mapping and carries an IR temperature sensor, analog distance sensor, and an inertial measurement unit (IMU) inside a protective shell. The first field test succeeded in collecting valuable scientific data but revealed several needed improvements, including more rugged cable connections and mechanical couplers, increased ground clearance, and higher-torque motors for uphill mobility. The second field test significantly improved on all of these aspects but it traded electrical ruggedness for reduced data collection speed. Data collected by the VolcanoBots, while intermittent, yield the first insights into the cm-scale geometry of volcanic fissures at depths of up to 25 m. VolcanoBot was deployed at the 1969 Mauna Ulu fissure system on Kīlauea volcano in Hawai'i. It collected first-of-its-kind data from inside the fissure system. We hypothesized that 1) fissure sinuosity should decrease with depth, 2) irregularity should be persistent with depth, 3) any blockages in the conduit should occur at the narrowest points, and 4) the fissure should narrow with depth until it is too narrow for VolcanoBot to pass or is plugged with solidified lava. Our field campaigns did not span enough lateral or vertical area to test sinuosity. The preliminary data indicate that 1) there were many irregularities along fissures at depth, 2) blockages occurred, but not at obviously narrow locations, and 3) the conduit width remained a consistent 0.4-0.5 m for most of the upper 10 m that we analyzed.

  1. Anthropometric Analysis of Palpebral Fissure Dimensions and its Position in South Indian Ethnic Adults

    PubMed Central

    Vasanthakumar, P.; Kumar, Pramod; Rao, Mohandas

    2013-01-01

    Objectives The morphology and anatomical relationship of periorbital features vary according to age, sex and ethnicity. Standard database regarding periorbital region is available for other ethnic groups. Since there is no data available in the literature, specifically for south Indian ethnic adults, the present study was carried out to determine the normal average values for South Indian ethnic population related to gender. Methods Anthropometric measurements of both eyes were done on standardized frontal view photograph of 200 South Indian ethnic adults aged 18 to 26 years. Parameters included were palpebral fissure width (PFW), palpebral fissure height (PFH), palpebral fissure inclination (PFI), outercanthal distance (OCD), interpupillary distance (IPD), intercanthal distance (ICD) and comparisons were made between the genders using the independent t test. Results Significant sexual dimorphism was noted in the given parameters. Palpebral fissure width (male: 31.08 mm; female: 29.90 mm), palpebral fissure inclination (male: 5.053°; female: 6.102°), outercanthal distance (male: 95.55 mm; female: 92.44 mm) and interpupillary distance (male: 66.72 mm; female: 62.59 mm). The palpebral fissure height (male: 11.30 mm; female: 11.58 mm) and intercanthal distance (male: 34.27 mm; female: 33.41 mm) showed no significant sexual differences. Conclusion Statistically significant differences were found between South Indian ethnic males and female in certain key parameters. The present study suggests that ethnicity and gender should be considered in orbital surgery. To individualize the treatment planning and diagnosis, it is important for the surgeons to have knowledge of these local norms. PMID:23386941

  2. [Saccular aneurysm of the azygos vein in a patient with azygos accessory fissure].

    PubMed

    Córdoba Rovira, S M; Guedea Martin, A; Salvador Adell, I; Elias Artiga, J

    2015-01-01

    The saccular aneurysm of the azygos vein is an extremely rare condition, which when located in the path of an accesory pulmonary fissure, becomes a diagnostic challenge because it can be mistaken for tumors arising from the accesory pleura, like solitary fibrous tumor of the pleura or mesothelioma. The diagnosis should ideally be done by non-invasive methods such as CT or MR angiographic technique in multiple phases, thus avoiding unnecessary surgical intervention. This case is exceptional because, to our knowledge, it is the first to report both concomitant clinical situations, an aneurysm of the azygos vein in the pathway of its accessory fissure.

  3. Breeding for rice fissure resistance made possible through development of a new selection technique and identification of molecular gene tags

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Value: One of the primary causes of rice grain breakage during milling is fissuring, or cracking, of the rice before it enters the mill. Any reduction in kernel fissuring can result in direct increases in profit for both producers and millers. For a producer yielding 7,000 lb/A paddy, even a small (...

  4. The Fissure Tolbachik Basalt Eruption, Kamchatka (2012-2013): main results of its studying

    NASA Astrophysics Data System (ADS)

    Muravyev, Y. D.; Gordeev, E.; Droznin, V. A.; Volynets, A. O.

    2013-12-01

    There is a large volcanic center in the south part of the Klyuchevskaya group of volcanoes, for which fissure eruptions of mafic lavas are typical in historic times. The latest large effusion of lavas in this zone occurred over the period 1975-1976 and was called the Great Tolbachik fissure eruption (GTFE 1975-76). After 37 years of rest, in the evening of November 27, 2012 liquid basalts star ted to effuse extensively to the south of Plosky Tolbachik Volcano. One day prior to the eruption, a swarm of ear thquakes was recorded beneath the volcano. Seismic data showed that the fissure opened at 17h45m local time at an altitude of about 2.5 km on the souther n flank of Plosky Tolbachik. The fissure stretched 6 km from nor th to south. Local residents repor ted three areas of eruptions late at night. The eruption was obviously explosive in the upper part of the fissure. At this stage the fissure produced the most powerful ash emissions resulting in ash deposits as far as several tens of kilometers from the volcano. In its lower part the fissure star ted to produce extremely fluid basaltic lava. A small lava flow from the central area of eruption traveled to the west and descended 9 km along the valley of Vodopadny creek to a height of 650 m a.s.l. and destroyed Vodopadnaya base camp, which had been built during the 1975-1976 Great Tolbachik fissure eruption. By November 30, the movement of Vodopadny lava flow had ceased. The main lava flow resulted from the central part of the fissure. Gradually, the main eruptive center with up to three vents was formed above the upper fissure. The vents activity varies in time. By mid January 2013 a crater with a lava lake had been formed above the upper fissure. The crater is continuously fountaining hot material. Over the period of two months the erupted lava had covered an area of 30 km2. New portions of lava are coming to the surface along the lava channels increasing the thickness of the lava field. Sometimes lava bursts out of

  5. Response of rock-fissure seepage to snowmelt in Mount Taihang slope-catchment, North China.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun

    2013-01-01

    The complex physiographic and hydrogeological systems of mountain terrains facilitate intense rock-fissure seepages and multi-functional ecological interactions. As mountain eco-hydrological terrains are the common water sources of river basins across the globe, it is critical to build sufficient understanding into the hydrological processes in this unique ecosystem. This study analyzes infiltration and soil/rock-fissure seepage processes from a 65 mm snowfall/melt in November 2009 in the typical granitic gneiss slope catchment in the Taihang Mountains. The snowfall, snowmelt and melt-water processes are monitored using soil-water time-domain reflectometry (TDR) probes and tipping bucket flowmeters. The results suggest that snowmelt infiltration significantly influences soil/rock water seepage in the 0-100 cm soil depth of the slope-catchment. It is not only air temperature that influences snowmelt, but also snowmelt infiltration and rock-fissure seepage. Diurnal variations in rock-fissure seepage are in close correlation with air temperature (R(2) > 0.7). Temperature also varies with soil/rock water viscosity, which element in turn influences soil/rock water flow. Invariably, water dynamics in the study area is not only a critical water supply element for domestic, industrial and agricultural uses, but also for food security and social stability.

  6. A comparison between three different pit and fissure sealants with regard to marginal integrity

    PubMed Central

    Fernandes, Kristlee Sabrin; Chalakkal, Paul; de Ataide, Ida de Noronha; Pavaskar, Rajdeep; Fernandes, Precylia Philo; Soni, Harleen

    2012-01-01

    Aim: The aim of this study is to compare the occurrence of enamel fractures, sealant fractures and marginal fissures after placement of three sealants: Helioseal F, Conseal F and Clinpro. Materials and Methods: Thirty individuals between 13 and 15 years of age, diagnosed with pit and fissure caries by visual and DIAGNOdent examination, were chosen for sealant placement on their mandibular molars. The sealants were placed at random, after which, impressions were made with polyvinyl siloxane and casts were fabricated. Dies were prepared, each of which were sputter coated with gold in order to be examined under a scanning electron microscope. The following morphologies were analyzed from dies from each of the sealant groups: Continuous margins, sealant fractures, marginal fissures and enamel fractures. After six months, they were recalled for impression making. Dies were prepared and microscopically analyzed as mentioned. Based on the time of evaluation, there were two groups: Initial group (soon after placement) and final group (after six months). Statistical analysis was done using the paired ‘t’ test and One-way analysis of variance (ANOVA). Results and Conclusions: Clinpro had the greatest fracture resistance, followed by Conseal F and Helioseal F. The occurrence of marginal fissure was found to be least with Clinpro. PMID:22557813

  7. Giant desiccation fissures on the Black Rock and Smoke Creek Deserts, Nevada

    USGS Publications Warehouse

    Willden, R.; Mabey, D.R.

    1961-01-01

    Open fissures, from 100 to several hundred feet apart, that have produced polygonal patterns on the Black Rock Desert, Nevada, are believed to be giant desiccation cracks resulting from a secular trend toward aridity in the last few decades. Similar features on the Smoke Creek Desert probably have the same origin.

  8. Anatomy of the Inferior Orbital Fissure: Implications for Endoscopic Cranial Base Surgery

    PubMed Central

    De Battista, Juan Carlos; Zimmer, Lee A.; Theodosopoulos, Philip V.; Froelich, Sebastien C.; Keller, Jeffrey T.

    2012-01-01

    Considering many approaches to the skull base confront the inferior orbital fissure (IOF) or sphenomaxillary fissure, the authors examine this anatomy as an important endoscopic surgical landmark. In morphometric analyses of 50 adult human dry skulls from both sexes, we divided the length of the IOF into three segments (anterolateral, middle, posteromedial). Hemotoxylin- and eosin-stained sections were analyzed. Dissections were performed using transnasal endoscopy in four formalin-fixed cadaveric cranial specimens (eight sides); three endoscopic approaches to the IOF were performed. IOF length ranged from 25 to 35 mm (mean 29 mm). Length/width of the individual anterolateral, middle, and posteromedial segments averaged 6.46/5, 4.95/3.2, and 17.6/ 2.4 mm, respectively. Smooth muscle within the IOF had a consistent relationship with several important anatomical landmarks. The maxillary antrostomy, total ethmoidectomy approach allowed access to the posteromedial segment of the fissure. The endoscopic modified, medial maxillectomy approach allowed access to the middle and posterior-medial segment. The Caldwell-Luc approach allowed complete exposure of the IOF. The IOF serves as an important anatomic landmark during endonasal endoscopic approaches to the skull base and orbit. Each of the three segments provides a characteristic endoscopic corridor, unique to the orbit and different fossas surrounding the fissure. PMID:23542710

  9. Study of Operated Patients of Lateral Internal Anal Sphincterotomy for Chronic Anal Fissure

    PubMed Central

    Patel, Harshad Shankarlal; Chavda, Jagdish; Parikh, Jayesh; Naik, Nehal

    2013-01-01

    Introduction: Anal fissure causes significant morbidity in the population. It is proposed that elevated sphincter pressures may cause ischaemia of the anal lining and this may be responsible for the pain of anal fissures and their failure to heal. When pharmacologic therapy fails or fissures recur frequently, lateral internal sphincterotomy is the surgical treatment of choice. Material and Methods: Retrospective analysis was done of admitted and operated patients of anal fissure by lateral anal internal sphincterotomy either by open or closed technique between April 2010 and November 2011 in Gujarat Medical Education & Research Society Medical College, Sola, Ahmedabad, India. The follow-up data of all patients was evaluated for pain relief, recurrence, wound infection, incontinence to flatus or stool or both for a period of up to 6 months. Results: Wound infection rate was 10.3% in open method and 4.2% in closed method. Incontinence to flatus was 8.3% in closed method and 3.4% in open method. This was temporary and controlled within a 1 week. Incontinence to stool was 3.4% in open method which was temporary and controlled within 2 weeks while none in closed method. None of the patients in either group had come with recurrence within 6 months follow-up. Conclusion: Lateral anal internal sphincterotomy is safe regarding long term incontinence and effective regarding recurrence. PMID:24551659

  10. Response of rock-fissure seepage to snowmelt in Mount Taihang slope-catchment, North China.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun

    2013-01-01

    The complex physiographic and hydrogeological systems of mountain terrains facilitate intense rock-fissure seepages and multi-functional ecological interactions. As mountain eco-hydrological terrains are the common water sources of river basins across the globe, it is critical to build sufficient understanding into the hydrological processes in this unique ecosystem. This study analyzes infiltration and soil/rock-fissure seepage processes from a 65 mm snowfall/melt in November 2009 in the typical granitic gneiss slope catchment in the Taihang Mountains. The snowfall, snowmelt and melt-water processes are monitored using soil-water time-domain reflectometry (TDR) probes and tipping bucket flowmeters. The results suggest that snowmelt infiltration significantly influences soil/rock water seepage in the 0-100 cm soil depth of the slope-catchment. It is not only air temperature that influences snowmelt, but also snowmelt infiltration and rock-fissure seepage. Diurnal variations in rock-fissure seepage are in close correlation with air temperature (R(2) > 0.7). Temperature also varies with soil/rock water viscosity, which element in turn influences soil/rock water flow. Invariably, water dynamics in the study area is not only a critical water supply element for domestic, industrial and agricultural uses, but also for food security and social stability. PMID:23128629

  11. Identification of genetic loci underlying the kernel fissure-resistance exhibited by 'cypress' and 'saber'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of broken rice is about half that of whole milled rice, so one goal of producers, millers, and rice breeders is to reduce broken grains that result from the dehusking and milling processes One of the primary causes of rice breakage is fissuring, or cracking, of the rice before it ...

  12. Rice fissure resistance QTLs from ‘Saber’ complement those from ‘Cypress’

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The economic value of broken rice is about half that of whole milled rice, so one goal of producers, millers, and rice breeders is to reduce grain breakage during the dehusking and milling processes. One of the primary causes of rice breakage is fissuring, or cracking, of the rice before it enters ...

  13. Methods for monitoring land subsidence and earth fissures in the Western USA

    NASA Astrophysics Data System (ADS)

    Fergason, K. C.; Rucker, M. L.; Panda, B. B.

    2015-11-01

    Depletion of groundwater resources in many deep alluvial basin aquifers in the Western USA is causing land subsidence, as it does in many regions worldwide. Land subsidence can severely and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to compromise the foundations of dams, levees, and other infrastructure and cause failure. Subsequent to an evaluation of the overall subsidence experienced in the vicinity of subsidence-impacted infrastructure, a detailed investigation to search for earth fissures, and design and/or mitigation of potentially effected infrastructure, a focused monitoring system should be designed and implemented. Its purpose is to provide data, and ultimately knowledge, to reduce the potential adverse impacts of land subsidence and earth fissure development to the pertinent infrastructure. This risk reduction is realized by quantifying the rate and distribution of ground deformation, and to detect ground rupture if it occurs, in the vicinity of the infrastructure. The authors have successfully designed and implemented monitoring systems capable of quantifying rates and distributions of ground subsidence and detection of ground rupture at multiple locations throughout the Western USA for several types of infrastructure including dams, levees, channels, basins, roadways, and mining facilities. Effective subsidence and earth fissure monitoring requires understanding and quantification of historic subsidence, estimation of potential future subsidence, delineation of the risk for earth fissures that could impact infrastructure, and motivation and resources to continue monitoring through time. A successful monitoring system provides the means to measure ground deformation, grade changes, displacement, and anticipate and assess the potential for earth fissuring. Employing multiple

  14. Enamel Surface with Pit and Fissure Sealant Containing 45S5 Bioactive Glass.

    PubMed

    Yang, S-Y; Kwon, J-S; Kim, K-N; Kim, K-M

    2016-05-01

    Enamel demineralization adjacent to pit and fissure sealants leads to the formation of marginal caries, which can necessitate the replacement of existing sealants. Dental materials with bioactive glass, which releases ions that inhibit dental caries, have been studied. The purpose of this study was to evaluate the enamel surface adjacent to sealants containing 45S5 bioactive glass (BAG) under simulated microleakage between the material and the tooth in a cariogenic environment. Sealants containing 45S5BAG filler were prepared as follows: 0% 45S5BAG + 50.0% glass (BAG0 group), 12.5% 45S5BAG + 37.5% glass (BAG12.5 group), 25.0% 45S5BAG + 25.0% glass (BAG25.0 group), 37.5% 45S5BAG + 12.5% glass (BAG37.5 group), and 50.0% 45S5BAG + 0% glass (BAG50.0 group). A cured sealant disk was placed over a flat bovine enamel disk, separated by a 60-µm gap, and immersed in lactic acid solution (pH 4.0) at 37 °C for 15, 30, and 45 d. After the storage period, each enamel disk was separated from the cured sealant disk, and the enamel surface was examined with optical 3-dimensional surface profilometer, microhardness tester, and scanning electron microscopy. The results showed a significant increase in roughness and a decrease in microhardness of the enamel surface as the proportion of 45S5BAG decreased (P< 0.05). In the scanning electron microscopy images, enamel surfaces with BAG50.0 showed a smooth surface, similar to those in the control group with distilled water, even after prolonged acid storage. Additionally, an etched pattern was observed on the surface of the demineralized enamel with a decreasing proportion of 45S5BAG. Increasing the 45S5BAG filler contents of the sealants had a significant impact in preventing the demineralization of the enamel surface within microgaps between the material and the tooth when exposed to a cariogenic environment. Therefore, despite some marginal leakage, these novel sealants may be effective preventive dental materials for inhibiting

  15. Enamel Surface with Pit and Fissure Sealant Containing 45S5 Bioactive Glass.

    PubMed

    Yang, S-Y; Kwon, J-S; Kim, K-N; Kim, K-M

    2016-05-01

    Enamel demineralization adjacent to pit and fissure sealants leads to the formation of marginal caries, which can necessitate the replacement of existing sealants. Dental materials with bioactive glass, which releases ions that inhibit dental caries, have been studied. The purpose of this study was to evaluate the enamel surface adjacent to sealants containing 45S5 bioactive glass (BAG) under simulated microleakage between the material and the tooth in a cariogenic environment. Sealants containing 45S5BAG filler were prepared as follows: 0% 45S5BAG + 50.0% glass (BAG0 group), 12.5% 45S5BAG + 37.5% glass (BAG12.5 group), 25.0% 45S5BAG + 25.0% glass (BAG25.0 group), 37.5% 45S5BAG + 12.5% glass (BAG37.5 group), and 50.0% 45S5BAG + 0% glass (BAG50.0 group). A cured sealant disk was placed over a flat bovine enamel disk, separated by a 60-µm gap, and immersed in lactic acid solution (pH 4.0) at 37 °C for 15, 30, and 45 d. After the storage period, each enamel disk was separated from the cured sealant disk, and the enamel surface was examined with optical 3-dimensional surface profilometer, microhardness tester, and scanning electron microscopy. The results showed a significant increase in roughness and a decrease in microhardness of the enamel surface as the proportion of 45S5BAG decreased (P< 0.05). In the scanning electron microscopy images, enamel surfaces with BAG50.0 showed a smooth surface, similar to those in the control group with distilled water, even after prolonged acid storage. Additionally, an etched pattern was observed on the surface of the demineralized enamel with a decreasing proportion of 45S5BAG. Increasing the 45S5BAG filler contents of the sealants had a significant impact in preventing the demineralization of the enamel surface within microgaps between the material and the tooth when exposed to a cariogenic environment. Therefore, despite some marginal leakage, these novel sealants may be effective preventive dental materials for inhibiting

  16. The cycle of instability: stress release and fissure flow as controls on gully head retreat

    NASA Astrophysics Data System (ADS)

    Collison, A. J. C.

    2001-01-01

    Gully head and wall retreat has commonly been attributed to fluvial scour and head collapse as a result of soil saturation, sapping or piping. The empirical evidence to substantiate these conceptual models is sparse, however, and often contradictory. This paper explores the hydrological and mechanical controls on gully head and wall stability by modelling the hydrology, stability and elastic deformation of a marl gully complex in Granada Province, south-east Spain. The hydrological and slope-stability simulations show that saturated conditions can be reached only where preferential fissure flow channels water from tension cracks into the base of the gully head, and that vertical or subvertical heads will be stable unless saturation is achieved. Owing to the high unsaturated strengths of marl measured in this research, failure in unsaturated conditions is possible only where the gully head wall is significantly undercut. Head retreat thus requires the formation of either a tension crack or an undercut hollow. Finite-element stress analysis of eroding slopes reveals a build up of shear stress at the gully head base, and a second stress anomaly just upslope of the head wall. Although tension cracks on gully heads have often been attributed to slope unloading, this research provides strong evidence that the so called sapping hollow commonly found in the gully headwall base is also a function of stress release. Although further research is needed, it seems possible that pop out failures in river channels may be caused by the same process. The hydrological analysis shows that, once a tension crack has developed, throughflow velocity in the gully headwall will increase by an order of magnitude, promoting piping and enlargement of this weakened area. It is, therefore, possible to envisage a cycle of gully expansion in which erosion, channel incision or human action unloads the slope below a gully head, leading to stress patterns that account for the tension crack and a

  17. Soil gas composition from the 2001-2002 fissure in the Lakki Plain (Nisyros Island, Greece): evidences for shallow hydrothermal fluid circulation

    NASA Astrophysics Data System (ADS)

    Venturi, Stefania; Tassi, Franco; Kanellopoulos, Christos; Vaselli, Orlando; Caponi, Chiara; Ricci, Andrea; Raspanti, Alessio; Gallorini, Andrea; Cabassi, Jacopo; Vougioukalakis, Georges

    2016-04-01

    Nisyros volcano (Aegean Sea, Greece) is currently classified in the "Very High Threat" category (Kinvig et al., 2010). Although the last volcanic activity, consisting of phreatic eruptions, occurred in the 19th century, Nisyros experienced an intense seismic activity during 1996-1998 accompanied by ground deformation and changes in the chemistry of fumarolic gases (Chiodini et al., 2002), pointing to a renewed unrest. Between November 2001 and December 2002, a NNE-oriented 600 m long fissure opened in the vegetated central part of the Lakki Plain. The fissure, 1-5 m wide and up to 15-20 m deep, showed neither vertical displacements nor gas release. No changes in the seismic and volcanic activity were observed during or after this event, which was interpreted as related to collapse of the upper caldera floor fine sediment cover (<50 m thick) induced by hydrothermal fluid circulation (Vougioukalakis and Fytikas, 2005). In June 2015, diffuse CO2 flux measurements, in combination with sampling and chemical analysis of the interstitial soil gases, were performed in (i) the fissure bottom, (ii) the adjacent vegetated areas in the Lakki Plain, (iii) the near hydrothermal craters (Stefanos, Kaminakia, Lofos domes), and (iv) sites located outside the caldera (blank values). The fissure showed neither temperature (<30 °C) nor CO2 fluxes (<10 gm-2d-1) anomalies with respect to the blank sites and the Lakki Plain, with values strikingly lower than those measured in the hydrothermal craters (up to 98 °C and 208 gm-2d-1, respectively). Contrarily, the CO2 concentrations in the interstitial soil gases from the fissure (up to 513 mmol/mol) were markedly higher than the background values and comparable with those measured in the craters (up to 841 mmol/mol). Relatively high H2S, H2 and CH4 contents in soil gases from the fissure confirm the hydrothermal origin of these soil gases. However, their CH4/CO2 ratio were lower than those measured in the soil gases from the craters

  18. A case of focal lung infarction following right upper lobectomy in case of undeveloped lung fissure.

    PubMed

    Parissis, Haralabos; Booth, Karen; Al-Alao, Bassel

    2015-09-01

    We present a case of infarction of residual upper lobe tissue during right upper lobectomy. We believe that although the blood supply to the upper lobe had been isolated and divided in order to perform the right upper lobectomy, residual right upper lobe had been left behind secondary to "poorly estimated" staple separation of the upper from the middle lobe in a patient with non-developed oblique fissure. We suggest that in this situation the upper lobe bronchus should be identified and clamped and the lung re-inflated in order to accurately demarcate the borders of the upper and middle lobe prior to the application of the stapler to prevent infarction of residual upper lobe tissue. Therefore, this case emphasises that routine lung inflation during fissure development in right upper lobectomy may prevent unpredictable complications.

  19. Painful ophthalmoplegia secondary to a mucocele involving the sella turcica, superior orbital fissure, and sphenoid sinus.

    PubMed

    Clarke, H; Clarke, V; Gill, J; St John, A; Lashley, M

    1992-03-01

    A case of painful ophthalmoplegia associated with an extensive lesion involving the sella turcica, superior orbital fissure, and sphenoid sinus in a 57-year-old man is reported. Even though nasal and ocular symptoms and signs represent the usual features of sphenoidal mucoceles, extension to the intracranial cavity as seen in this lesion is rare. Surgical exploration via a sublabial, transseptal approach revealed a mucocele of the sphenoid sinus. This case exhibited extensive and aggressive behavior simulating a malignant neoplasm.

  20. Artificial recharge through a well in fissured carbonate rock, west St. Paul, Minnesota

    USGS Publications Warehouse

    Reeder, Harold O.; Wood, Warren W.; Ehrlich, G.G.; Sun, Ren Jen

    1976-01-01

    The injection test demonstrated that it is hydrologically feasible to recharge the Prairie du Chien Group and the Jordan Sandstone artificially through wells completed in the Prairie du Chien Group. The fissures in the Prairie du Chien Group act as conduits through which water spreads. The water passes into the Jordan Sandstone from the Prairie du Chien over a larger area than it would if it were injected directly into the Jordan.

  1. Evaluation of different types of enamel conditioning before application of a fissure sealant.

    PubMed

    Ciucchi, Philip; Neuhaus, Klaus W; Emerich, Marta; Peutzfeldt, Anne; Lussi, Adrian

    2015-01-01

    The aim of the study was to compare fissure sealant quality after mechanical conditioning of erbium-doped yttrium aluminium garnet (Er:YAG) laser or air abrasion prior to chemical conditioning of phosphoric acid etching or of a self-etch adhesive. Twenty-five permanent molars were initially divided into three groups: control group (n = 5), phosphoric acid etching; test group 1 (n = 10), air abrasion; and test group 2, (n = 10) Er:YAG laser. After mechanical conditioning, the test group teeth were sectioned buccolingually and the occlusal surface of one half tooth (equal to one sample) was acid etched, while a self-etch adhesive was applied on the other half. The fissure system of each sample was sealed, thermo-cycled and immersed in 5% methylene dye for 24 h. Each sample was sectioned buccolingually, and one slice was analysed microscopically. Using specialized software microleakage, unfilled margin, sealant failure and unfilled area proportions were calculated. A nonparametric ANOVA model was applied to compare the Er:YAG treatment with that of air abrasion and the self-etch adhesive with phosphoric acid (α = 0.05). Test groups were compared to the control group using Wilcoxon rank sum tests (α = 0.05). The control group displayed significantly lower microleakage but higher unfilled area proportions than the Er:YAG laser + self-etch adhesive group and displayed significantly higher unfilled margin and unfilled area proportions than the air-abrasion + self-etch adhesive group. There was no statistically significant difference in the quality of sealants applied in fissures treated with either Er:YAG laser or air abrasion prior to phosphoric acid etching, nor in the quality of sealants applied in fissures treated with either self-etch adhesive or phosphoric acid following Er:YAG or air-abrasion treatment.

  2. Comparative Evaluation of the Marginal Sealing Ability of two Commercially Available Pit and Fissure Sealants

    PubMed Central

    Moses, Joyson; Rangeeth, Bollam Nammalwar; Sivakumar, Subramanian

    2016-01-01

    Introduction The occlusal surfaces of the teeth usually have pits and fissures which provide a good environment for demineralization with minimal salivary access and make them caries prone. The success of pit and fissure sealing materials is highly dependent on the marginal sealing ability of the fissures. Aim The present study was carried out to evaluate and compare the marginal sealing ability of two commercially available pit and fissure sealants. Materials and Methods A total of 50 human premolar teeth were used in this invitro study. Group 1 included 25 teeth for application of Clinpro sealant and Group 2 included twenty 25 for application of Helioseal F sealant. Samples were stored in artificial saliva for 72 hours before thermocycling. The samples were immersed in 2% methylene blue solution for 24 hours. The sectioned samples were examined under an Optical Stereomicroscope and compared in terms of the extent of microleakage based on the amount of dye penetration between the sealant and tooth substance interface. The dye penetration scores in both the groups was statistically analysed using Chi square test and Mann Whitney Test. A p-value of less than 0.05 was considered to be statistically significant. Results It was seen that in Group 1, 12 samples (48%) had no dye penetration (Grade 0) while in Group 2, 6 samples (24%) demonstrated Grade 0 penetration. Group 2 had the most extensive dye penetration (Grade 3) in 8 of 25 samples (32%) (p=0.014). Conclusion On comparison of the microleakage scores of the groups, a statistically significant difference was found between the two groups; indicating a much better performance of Clinpro as compared to Helioseal F. PMID:27790568

  3. [Surgical therapy of chronic anal fissure--do additional proctologic operations impair continence?].

    PubMed

    Pfeifer, J; Berger, A; Uranüs, S

    1994-07-01

    78 patients with chronic anal fissures have been mainly operated on by lateral internal sphincterotomy (LATS). Continence have been evaluated by questionnaire at least 9 months postoperatively. Patient without any additional proctological operation had minor disturbances of continence in 17%. Patient with additional operations had disturbances of continence in 30%. Especially the subgroup of patients with LATS and haemorrhoidectomy had bad results. In this group only 45% were fully continent.

  4. The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos

    USGS Publications Warehouse

    Chadwick, W.W.; Howard, K.A.

    1991-01-01

    Maps of the eruptive vents on the active shield volcanoes of Fernandina and Isabela islands, Galapagos, made from aerial photographs, display a distinctive pattern that consists of circumferential eruptive fissures around the summit calderas and radial fissures lower on the flanks. On some volcano flanks either circumferential or radial eruptions have been dominant in recent time. The location of circumferential vents outside the calderas is independent of caldera-related normal faults. The eruptive fissures are the surface expression of dike emplacement, and the dike orientations are interpreted to be controlled by the state of stress in the volcano. Very few subaerial volcanoes display a pattern of fissures similar to that of the Galapagos volcanoes. Some seamounts and shield volcanoes on Mars morphologically resemble the Galapagos volcanoes, but more specific evidence is needed to determine if they also share common structure and eruptive style. ?? 1991 Springer-Verlag.

  5. Arteries and Veins of the Sylvian Fissure and Insula: Microsurgical Anatomy.

    PubMed

    Delion, Matthieu; Mercier, Philippe; Brassier, Gilles

    2016-01-01

    We present a vascular anatomical study of the arteries and veins of the sylvian fissure and insula.A good knowledge of the sylvian fissure, the insula, and their vascular relationship would seem mandatory before performing surgery in this area, whatever the type of surgery (aneurysms, arteriovenous malformations, insular tumors).We start with the sylvian fissure and insula morphology, followed by the MCA description and its perforators, with special attention paid to the insular perforators. We demonstrate that the long insular perforators penetrating in the superior part of the posterior short gyrus and long gyri vascularize, respectively, the corticonuclear and corticospinal fasciculi. We particularly insist too on three anatomical constants regarding the vascularization of the insula, already described in the literature: The superior periinsular sulcus is the only sulcus on the lateral surface of the brain without an artery along its axis; the superior branch of the MCA supplies the anterior insular pole and both the anterior and middle short gyri in 100 % of cases; in at least 90 % of cases, the artery that supplied the central insular sulcus continued on to become the central artery.We end with the anatomical study of the veins and cisterns.

  6. Squamotympanic fissure in the Ngandong and Sambungmacan hominids: a reply to Delson et al.

    PubMed

    Durband, Arthur C

    2002-03-01

    In the present study the course of the squamotympanic fissure of the mandibular fossa is examined in several fossil hominid specimens. While previous work by several authors had found that the course of this fissure was potentially autapomorphic for the Ngandong and Sambungmacan fossil samples from Indonesia, a more recent study performed by Delson et al. (Anat Rec 2001; 262:380--397) reported that a number of other fossils, including OH 9, Sangiran 4 and 17, and KNM WT 15000 were similar to the Ngandong and Sambungmacan specimens in the expression of this feature. To test these findings, those specimens purported to share similarities with Ngandong and Sambungmacan were examined. The results of this study indicate clearly differing morphologies between the Ngandong and Sambungmacan fossils, on the one hand, and the four African and Indonesian fossils named by Delson et al. (2001). Hence, the course of the squamotympanic fissure remains a potentially autapomorphic feature separating the Ngandong and Sambungmacan samples from the remaining specimens allocated to Homo erectus.

  7. Endoscopic endonasal anatomy of superior orbital fissure and orbital apex regions: critical considerations for clinical applications.

    PubMed

    Dallan, Iacopo; Castelnuovo, Paolo; de Notaris, Matteo; Sellari-Franceschini, Stefano; Lenzi, Riccardo; Turri-Zanoni, Mario; Battaglia, Paolo; Prats-Galino, Alberto

    2013-05-01

    The superior orbital fissure is a critical three-dimensional space connecting the middle cranial fossa and the orbit. From an endoscopic viewpoint, only the medial aspect has a clinical significance. It presents a critical relationship with the lateral sellar compartment, the pterygopalatine fossa and the middle cranial fossa. The connective tissue layers and neural and vascular structures of this region are described. The role of Muller's muscle is confirmed, and the utility of the maxillary and optic strut is outlined. Muller's muscle extends for the whole length of the inferior orbital fissure, passes over the maxillary strut and enters the superior orbital fissure, representing a critical surgical landmark. Dividing the tendon between the medial and inferior rectus muscle allows the identification of the main trunk of the oculomotor nerve, and a little laterally, it is usually possible to visualize the first part of the ophthalmic artery. Based on a better knowledge of anatomy, we trust that this area could be readily addressed in clinical situations requiring an extended approach in proximity of the orbital apex.

  8. Resin infiltration of fissure caries with various techniques of pretreatment in vitro.

    PubMed

    Lausch, Julian; Paris, Sebastian; Selje, Timo; Dörfer, Christof E; Meyer-Lueckel, Hendrik

    2015-01-01

    The resin infiltration technique might be used for occlusal caries lesions in order to arrest their progression. This in vitro study evaluated the influence of various modifications of the infiltration technique on the penetration abilities of the infiltrant into occlusal lesions. Extracted human molars and premolars (n = 140) with non-cavitated white spot lesions were randomly allocated to 7 groups. As control, specimens were etched with 15% hydrochloric acid (HCl) gel for 120 s and resin infiltrated for 180 s (Icon; DMG). As modification HCl gel reduced in surface tension and viscosity with and without abrasives was applied using 3 different types of brushes either to oscillate or rub the HCl gel onto the enamel surface. The median maximum lesion depth was 1,232 µm (interquartile range 882-1,513). Compared with the control procedure [23% (16/50)] a higher percentage penetration was observed if the HCl gel was mixed with a small amount of abrasives were rubbed into the fissures using a modified brush with stiff bristles that were adjusted to the fissure relief for either 120 s [100% (64/100)] or 30 s [98% (61/100); p < 0.05; Mann-Whitney test]. All other experimental treatments resulted in penetration results in-between. It can be concluded that the use of an abrasive HCl gel in conjunction with a modified brush mostly enhances resin infiltration into fissure caries lesions. PMID:25427531

  9. An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Tian, Wen-Ling; Huang, Yan-Hua; Ranjith, P. G.; Ju, Yang

    2016-04-01

    To understand the fracture mechanism in all kinds of rock engineering, it is important to investigate the fracture evolution behavior of pre-fissured rock. In this research, we conducted uniaxial compression experiments to evaluate the influence of ligament angle on the strength, deformability, and fracture coalescence behavior of rectangular prismatic specimens (80 × 160 × 30 mm) of brittle sandstone containing two non-coplanar fissures. The experimental results show that the peak strength of sandstone containing two non-coplanar fissures depends on the ligament angle, but the elastic modulus is not closely related to the ligament angle. With the increase of ligament angle, the peak strength decreased at a ligament angle of 60°, before increasing up to our maximum ligament angle of 120°. Crack initiation, propagation, and coalescence were all observed and characterized from the inner and outer tips of pre-existing non-coplanar fissures using photographic monitoring. Based on the results, the sequence of crack evolution in sandstone containing two non-coplanar fissures was analyzed in detail. In order to fully understand the crack evolution mechanism of brittle sandstone, numerical simulations using PFC2D were performed for specimens containing two non-coplanar fissures under uniaxial compression. The results are in good agreement with the experimental results. By analyzing the stress field, the crack evolution mechanism in brittle sandstone containing two non-coplanar fissures under uniaxial compression is revealed. These experimental and numerical results are expected to improve the understanding of the unstable fracture mechanism of fissured rock engineering structures.

  10. Distributed Computing for Seismic Data Retrieval using FISSURES DHI Client FMI Implimented from MatSeis 1.9

    NASA Astrophysics Data System (ADS)

    Hart, D. M.; Li, Q.; Creager, K. C.; Ning, R.; Crotwell, H. P.; Zuzlewski, S.; Hellman, S. B.; Schoch, K. S.; Laughbon, C. J.; Stromme, S. R.

    2004-12-01

    Three software development efforts have recently combined to allow a seamless method for obtaining data from the IRIS DMC over the Internet and analyzing it in MATLAB. During the past few years IRIS has constructed the initial framework and definitions for FISSURES servers and Data Handling Interface (DHI) clients. FISSURES uses the distributed computing language Common Object Request Broker Architecture (CORBA), which allows software systems to work across the Internet in a platform independent and computer-language neutral manner. Starting from the FISSURES object model three seismic services have been defined: event, network and seismogram. From these three object types a DHI client is used to access information through FISSURES services. Using the University of Washington developed FISSURES-Matlab-Interface (FMI) DHI client, all three FISSURES objects can be accessed via the Internet and downloaded into local MATLAB objects, allowing access to earthquake event catalogs, seismograms, network and instrument information. The DHI client FMI can be implemented from MatSeis. MatSeis, developed at Sandia National Laboratory, is a MATLAB based, Graphical User Interface (GUI) controlled software package with seismic data visualization, signal processing, and database importing and exporting capabilities, to list just a few. In this poster, we will discuss the seismic data retrieval currently prototyped for the IRIS DMC, as well as the planned connections to the Northern California Earthquake Data Center (NCEDC), Southern California Earthquake Data Center (SCEDC), and South Carolina Earth Physics Project (SCEPP) data center.

  11. Method for laser drilling subterranean earth formations

    DOEpatents

    Shuck, Lowell Z.

    1976-08-31

    Laser drilling of subterranean earth formations is efficiently accomplished by directing a collimated laser beam into a bore hole in registry with the earth formation and transversely directing the laser beam into the earth formation with a suitable reflector. In accordance with the present invention, the bore hole is highly pressurized with a gas so that as the laser beam penetrates the earth formation the high pressure gas forces the fluids resulting from the drilling operation into fissures and pores surrounding the laser-drilled bore so as to inhibit deleterious occlusion of the laser beam. Also, the laser beam may be dynamically programmed with some time dependent wave form, e.g., pulsed, to thermally shock the earth formation for forming or enlarging fluid-receiving fissures in the bore.

  12. Land subsidence and earth fissures in south-central and southern Arizona, USA

    NASA Astrophysics Data System (ADS)

    Conway, Brian D.

    2016-05-01

    Land subsidence due to groundwater overdraft has been an ongoing problem in south-central and southern Arizona (USA) since the 1940s. The first earth fissure attributed to excessive groundwater withdrawal was discovered in the early 1950s near Picacho. In some areas of the state, groundwater-level declines of more than 150 m have resulted in extensive land subsidence and earth fissuring. Land subsidence in excess of 5.7 m has been documented in both western metropolitan Phoenix and Eloy. The Arizona Department of Water Resources (ADWR) has been monitoring land subsidence since 2002 using interferometric synthetic aperture radar (InSAR) and since 1998 using a global navigation satellite system (GNSS). The ADWR InSAR program has identified more than 25 individual land subsidence features that cover an area of more than 7,300 km2. Using InSAR data in conjunction with groundwater-level datasets, ADWR is able to monitor land subsidence areas as well as identify areas that may require additional monitoring. One area of particular concern is the Willcox groundwater basin in southeastern Arizona, which is the focus of this paper. The area is experiencing rapid groundwater declines, as much as 32.1 m during 2005-2014 (the largest land subsidence rate in Arizona State—up to 12 cm/year), and a large number of earth fissures. The declining groundwater levels in Arizona are a challenge for both future groundwater availability and mitigating land subsidence associated with these declines. ADWR's InSAR program will continue to be a critical tool for monitoring land subsidence due to excessive groundwater withdrawal.

  13. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    PubMed Central

    Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively. Conclusion: The ACP-containing pit and fissure sealant has the potential to inhibit enamel demineralization. How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and fissure sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14. PMID:27274148

  14. Fissure distribution at Mauna Loa (Hawaii) as an example to understand shallow magma transfer at volcanoes

    NASA Astrophysics Data System (ADS)

    La Marra, Daniele; Acocella, Valerio; Trusdell, Frank

    2016-04-01

    Mauna Loa (Hawaii) is the largest active shield volcano on the Island of Hawai'i, covering more than half of it and rising to 4,169 meters above sea level. The volcano hosts the Moku'aweoweo summit caldera, from which two elongated rift zones depart: the Northeast Rift Zone (NERZ) and the Southwest Rift Zone (SWRZ). Most of Mauna Loa's eruptions begin with lava fountains from a series of fissure vents in the summit region and then often migrate to vents down either rift zone. Mauna Loa volcano shows a distinctive feature, being characterized by minor radial eruptive fissures (not related to the two main rifts) on the NW flank only. This study tries to explain such a selective distribution of vents, and thus of shallow magma transfer. To this aim, we run numerical models with different amount of opening of the two rift zones of Mauna Loa, as well as different amount of slip on its SE flank. Our results suggest that the selective occurrence of the radial fissures may be explained by the competition between two processes: a) rift intrusion (especially along the NERZ), promoting the development of radial dikes along the NW flank; b) flank slip, inhibiting the development of the radial dikes on the SE flank. The opening of the two non-parallel main rift zones of Mauna Loa promotes the local extension necessary to develop the radial dikes on the NW flank. A general model for the development of a third branch of radial rift, which may be also applied to Mt. Etna and some volcanoes on the Canary Islands, is proposed.

  15. Performance of a conventional sealant and a flowable composite on minimally invasive prepared fissures.

    PubMed

    Francescut, Paola; Lussi, Adrian

    2006-01-01

    Three different fissure preparation procedures were tested and compared to the non-invasive approach using a conventional unfilled sealant and a flowable composite. Eighty permanent molars were selected and divided into 4 groups of 20 teeth each. All the teeth were split into 2 halves, and the exposed fissures were photographed under a microscope (35x) before and after being prepared using the following methods: (I) Er:YAG laser (KEY Laser, KaVo) 600 mJ pulse energy, 6 Hz; (II) diamond bur; (III) Er: YAG laser (KEY Laser, KaVo) 200 mJ pulse energy, 4 Hz; (IV) Control group: Powder jet cleaner (Prophyflex, KaVo, Germany). The pre-and postimages were superimposed in order to evaluate the amount of hard tissue removed. Ten teeth in each group were then acid etched and sealed with an unfilled sealant (Delton opaque, Dentsply), while the remaining 10 teeth were acid etched, primed and bonded (Prime & Bond NT, Dentsply) and sealed with a flowable composite (X-flow, DeTrey, Dentsply). Material penetration and microleakage were evaluated after thermocycling (5000 cycles) and staining with methylene blue 5%. ANOVA and Mann-Whitney tests were applied for statistical analysis. The laser 600 mJ and bur eliminated the greatest amount of hard tissue. The control teeth presented the least microleakage when sealed with Delton or X-flow. A correlation between material penetration and microleakage could not be statistically confirmed. Mechanical preparation prior to fissure sealing did not enhance the final performance of the sealant.

  16. Anal fissure

    MedlinePlus

    ... cream, if pain interferes with normal bowel movements Petroleum jelly Zinc oxide, 1% hydrocortisone cream, Preparation H, ... is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation ...

  17. Anal Fissure

    MedlinePlus

    Skip to main content ASCRS Patients Educational Resources Diseases and Conditions Patient Education Library Patient Success Stories Treatments and Screening Resources Find a Surgeon Hereditary Colorectal Cancer Registries Helpful Links Physicians ...

  18. Fissured Tongue

    MedlinePlus

    ... Executive Committee Board of Trustees Governance Past Presidents Staff/Contact History Awards Our Partners Membership Membership Categories Renew Your Membership Login Fellowship Academic Fellowship Affiliate Fellowship (AFAOM) Application Process Fellowship Study ...

  19. Addition of fluoride to pit and fissure sealants--a feasibility study.

    PubMed

    Swartz, M L; Phillips, R W; Norman, R D; Elliason, S; Rhodes, B F; Clark, H E

    1976-01-01

    The data obtained in this in vitro study indicate that contact with pit and fissure sealants to which NaF has been added in amounts ranging from 2 to 5% substantially increases the fluoride content of the enamel and reduces its solubility in acid. The properties of the materials do not seem to be impaired by the addition of fluoride in these amounts. It thus appears that this approach to providing a backup anticariogenic mechanism may, indeed, be feasible. However, further investigation must be done to confirm the anticariogenic effect and to establish the most efficacious means of fluoride incorporation in the materials.

  20. Treating pit-and-fissure caries: a systematic review and network meta-analysis.

    PubMed

    Schwendicke, F; Jäger, A M; Paris, S; Hsu, L Y; Tu, Y K

    2015-04-01

    For shallow or moderately deep pit-and-fissure lesions, various treatment options are available: (1) noninvasive treatments (e.g., fluoride application, antibacterial treatments, oral hygiene advice) avoid any dental hard tissue removal; (2) microinvasive treatments (e.g., sealing) remove only a few micrometers of hard tissues by etching; and minimally invasive methods (e.g., "preventive" resin/sealant restoration) remove carious dentin but avoid sacrificing sound tissues. We aimed at systematically reviewing and comparing these strategies for treating pit-and-fissure lesions in permanent teeth using network meta-analysis. Randomized or nonrandomized clinical trials investigating shallow or moderately deep primary caries lesions in fissured or pitted surfaces were included. We compared the risk of requiring invasive treatments or any retreatments in noninvasive, microinvasive, and minimally invasive treated lesions; untreated lesions were used as controls. Five electronic databases were systematically screened up to September 2013 and cross-referencing performed. Pairwise and network meta-analyses were performed and odds ratios and 95% confidence intervals (CI) calculated. Certainty of estimates was evaluated via GRADE criteria. From a total of 2,214 identified records, 14 studies representing 1,440 patients with 3,551 treated lesions were included. Pairwise meta-analysis found microinvasive and minimally invasive treated lesions to require less invasive retreatments than control lesions (odds ratios [95% confidence intervals]: 0.13 [0.07 to 0.26], 0.13 [0.03 to 0.50], respectively), whereas the estimate for noninvasively treated lesions remained nonsignificant (0.64 [0.39 to 1.06]). These findings were reflected in the strategy ranking stemming from network meta-analysis (first, minimally invasive; second, microinvasive; third, noninvasive). However, microinvasive treatment required significantly more total retreatments (including resealing) than minimally or

  1. Different scale land subsidence and ground fissure monitoring with multiple InSAR techniques over Fenwei basin, China

    NASA Astrophysics Data System (ADS)

    Zhao, C.; Zhang, Q.; Yang, C.; Zhang, J.; Zhu, W.; Qu, F.; Liu, Y.

    2015-11-01

    Fenwei basin, China, composed by several sub-basins, has been suffering severe geo-hazards in last 60 years, including large scale land subsidence and small scale ground fissure, which caused serious infrastructure damages and property losses. In this paper, we apply different InSAR techniques with different SAR data to monitor these hazards. Firstly, combined small baseline subset (SBAS) InSAR method and persistent scatterers (PS) InSAR method is used to multi-track Envisat ASAR data to retrieve the large scale land subsidence covering entire Fenwei basin, from which different land subsidence magnitudes are analyzed of different sub-basins. Secondly, PS-InSAR method is used to monitor the small scale ground fissure deformation in Yuncheng basin, where different spatial deformation gradient can be clearly discovered. Lastly, different track SAR data are contributed to retrieve two-dimensional deformation in both land subsidence and ground fissure region, Xi'an, China, which can be benefitial to explain the occurrence of ground fissure and the correlation between land subsidence and ground fissure.

  2. One-year clinical evaluation of a Glass Carbomer fissure sealant, a preliminary study.

    PubMed

    Gorseta, K; Glavina, D; Borzabadi-Farahani, A; Van Duinen, R N; Skrinjaric, I; Hill, R G; Lynch, E

    2014-06-01

    Glass Carbomer is a new generation of restorative material developed from glass-ionomer cements with possibility of gradual mineralization into fluorapatite. The aim of this clinical trial was to investigate the retention of Glass Carbomer fissure sealant after 12 months, in comparison to a commonly used conventional resin-based sealant. Forty-eight teeth in 24 patients [mean (SD) = 8 (2.3) years] with well-delineated fissure morphology were randomly divided into two equal groups and sealed with Bis-GMA resin-based Helioseal F (group A, Ivoclar Vivadent, Liechtenstein) and Glass Carbomer (group B, Glass Carbomer Sealant, Glass Carbomer Products, Leiden, Netherlands) using the split mouth design. Materials were placed and set according to the manufacturer's instructions using a polymerization unit Bluephase 16i (Vivadent, Liechtenstein). Complete sealant retentions in both groups were 100% and 75% after 6 and 12 months of clinical service, respectively. There were there were no secondary caries lesions in both groups after 6 months; two new carious lesions were detected in both groups after 12 months. The Mann-Whitney U test revealed no significant difference between the two groups at both evaluations points (P > 0.05). Glass Carbomer material showed a similar retention rate when compared with a resin-based sealant. Future studies are required to examine the long-term performance of Glass Carbomer sealants. PMID:25134364

  3. Dermal flap advancement combined with conservative sphincterotomy in the treatment of chronic anal fissure.

    PubMed

    Theodoropoulos, George E; Spiropoulos, Vasileios; Bramis, Konstantinos; Plastiras, Aris; Zografos, George

    2015-02-01

    Lateral internal sphincterotomy (LIS) is considered the surgical treatment of choice for chronic anal fissure (CAF). Flap techniques for fissure coverage have the advantage of primary wound healing, potentially providing better functional results and faster pain relief. The standard surgical strategy for CAF consisting of conventional LIS (CLIS) up to the dentate line was modified by "tailoring" the LIS to the apex of the CAF, but never greater than 1 cm, and by advancing a dermal flap for coverage of the CAF (LIS + flap) after fissurectomy. Thirty consecutive patients who underwent "LIS + flap" were compared with 32 patients who had been previously treated by CLIS. A modified, trapezoid-like Y-V flap from perianal skin was advanced into the CAF base. Pain at the first postoperative day, pain at defecation during the first week, postoperative use of analgesics, and time for patients' pain relief were significantly less at the "LIS + flap" group (P < 0.01). Objective healing was achieved faster (P < 0.01) and soiling episodes were less (P < 0.05) after "LIS + flap." The addition of a dermal flap after "conservative" LIS resulted in better healing and significantly less postoperative discomfort than the isolated application of CLIS.

  4. Monitoring an eruption fissure in 3D: video recording, particle image velocimetry and dynamics

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2015-04-01

    The processes during an eruption are very complex. To get a better understanding several parameters are measured. One of the measured parameters is the velocity of particles and patterns, as ash and emitted magma, and of the volcano itself. The resulting velocity field provides insights into the dynamics of a vent. Here we test our algorithm for 3 dimensional velocity fields on videos of the second fissure eruption of Bárdarbunga 2014. There we acquired videos from lava fountains of the main fissure with 2 high speed cameras with small angles between the cameras. Additionally we test the algorithm on videos from the geyser Strokkur, where we had 3 cameras and larger angles between the cameras. The velocity is calculated by a correlation in the Fourier space of contiguous images. Considering that we only have the velocity field of the surface smaller angles result in a better resolution of the existing velocity field in the near field. For general movements also larger angles can be useful, e.g. to get the direction, height and velocity of eruption clouds. In summary, it can be stated that 3D velocimetry can be used for several application and with different setup due to the application.

  5. Effects of aging on surface properties and adhesion of Streptococcus mutans on various fissure sealants.

    PubMed

    Bürgers, Ralf; Cariaga, Tashiana; Müller, Rainer; Rosentritt, Martin; Reischl, Udo; Handel, Gerhard; Hahnel, Sebastian

    2009-12-01

    The aim of the present study was the quantification of Streptococcus mutans adhesion on ten widely used pit and fissure sealant materials and the correlation of these findings to surface roughness (R(a)) and surface free energy (SFE). Additionally, changes in streptococcal adhesion and surface parameters after water immersion and artificial aging have been investigated. Circular specimens of ten fissure sealants (seven resin-based composites, two glass ionomers, and one compomer) were made and polished. Surface roughness was determined by perthometer and SFE by goniometer measurements. Sealant materials were incubated with S. mutans suspension (2.5 h, 37 degrees C), and adhering bacteria were quantified by using a biofluorescence assay in combination with an automated plate reader. Surface properties and S. mutans adhesion were measured prior to and after water immersion after 1 and 6 months and after additional thermocycling (5,000 cycles; 5 degrees C/55 degrees C). The tested sealants showed significant differences in S. mutans adhesion prior to and after the applied aging procedures. Aging resulted in slight increases (mostly <0.2 microm) in surface roughness, as well as in significant decreases in SFE and in significantly lower quantities of adhering bacteria. Ketac Bond and UltraSeal XT plus revealed the lowest adhesion potential after artificial aging. In general, the amount of adhering S. mutans was reduced after aging, which may be related to the decline in SFEs.

  6. Maintenance therapy with unprocessed bran in the prevention of acute anal fissure recurrence.

    PubMed Central

    Jensen, S L

    1987-01-01

    The effect of unprocessed bran in a dose of 5 g three times daily and a dose of 2.5 g three times daily for one year on the recurrence rate of anal fissures was studied in a double-blind, placebo-controlled trial in 90 patients with recently healed acute posterior anal fissures. Fifteen patients (16.6%) were withdrawn before the code was broken due to failure to follow the trial protocol for various reasons. Significantly fewer recurrences occurred in patients receiving bran 5 g three times daily (recurrence rate 16%, 95% confidence limits, 4.54 to 36.08) when compared with patients receiving bran 2.5 g three times daily (60%; 38.67 to 78.87) (P less than 0.01) and with patients receiving placebo three times daily (68%; 46.50 to 85.05) (P less than 0.01). No significant difference in recurrences was found between patients on bran 2.5 g and those on placebo. PMID:3039130

  7. Botulinum toxin for chronic anal fissure after biliopancreatic diversion for morbid obesity

    PubMed Central

    Vanella, Serafino; Brisinda, Giuseppe; Marniga, Gaia; Crocco, Anna; Bianco, Giuseppe; Maria, Giorgio

    2012-01-01

    AIM: To study the effect of botulinum toxin in patients with chronic anal fissure after biliopancreatic diversion (BPD) for severe obesity. METHODS: Fifty-nine symptomatic adults with chronic anal fissure developed after BPD were enrolled in an open label study. The outcome was evaluated clinically and by comparing the pressure of the anal sphincters before and after treatment. All data were analyzed in univariate and multivariate analysis. RESULTS: Two months after treatment, 65.4% of the patients had a healing scar. Only one patient had mild incontinence to flatus that lasted 3 wk after treatment, but this disappeared spontaneously. In the multivariate analysis of the data, two registered months after the treatment, sex (P = 0.01), baseline resting anal pressure (P = 0.02) and resting anal pressure 2 mo after treatment (P < 0.0001) were significantly related to healing rate. CONCLUSION: Botulinum toxin, despite worse results than in non-obese individuals, appears the best alternative to surgery for this group of patients with a high risk of incontinence. PMID:22416176

  8. Wear of two pit and fissure sealants in contact with primary teeth

    PubMed Central

    Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Borsatto, Maria Cristina

    2014-01-01

    Objectives: Wear simulations may provide an indication of the clinical performance of pit-and-fissure sealants when associated with primary teeth as counterbody, restricting the involved variables. The aim of this study was to evaluate wear of dental materials used as pit-and-fissure sealants in contact with primary teeth. Materials and Methods: A resinous sealant (Fluroshield®) and a resin-modified glass ionomer cement (Vitremer®) were selected in a post-plate design, using as counterbody primary tooth pins (4 × 4 × 2 mm) at 3 and 10 N vertical load, 1 Hz frequency, 900 wear cycles in artificial saliva (n = 15). Attrition coefficient values were obtained and the material and primary tooth volumes were analyzed. Data were analyzed statistically by ANOVA and Duncan's test (P < 0.05). Results: Fluroshield® presented the highest attrition coefficient values for the 3 N but these values decreased significantly for the 10 N load. The means for volume loss (3 mm) of the different samples after the wear test were not statistically different for the materials. The volume loss values for the primary teeth were statistically different and there was an increase in volume loss with the increase of the load applied in the wear tests. Conclusions: Differences were also observed with regard to the surface deformation characteristics. The wear rates of primary tooth enamel vary according to the type of material and the load applied during mastication. PMID:24966777

  9. The link between circumferential dikes and eruptive fissures around calderas: insights from numerical and analog models

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio

    2016-04-01

    Active calderas are seldom associated with circumferential eruptive fissures along their rim, but eroded portions of extinct magmatic complexes reveal widespread evidence of circumferential dikes. This discrepancy suggests that, while the conditions to emplace circumferential dikes below volcanoes are easily met, mechanisms must exist to arrest the dikes before they reach the surface. Here we explain this discrepancy with laboratory experiments of air injection into a gelatin medium shaped to mimic a volcanic edifice with caldera. Our models show that the ascending dikes experience a variable degree of deflection, depending on the competition between dike overpressure, Pe, and the forcing induced by the topographic load, Pl. When Pl/Pe = 4.3 - 4.5 the analog dikes proceed almost insensitive to the stress rotation and erupt within the caldera. When Pl/Pe = 4.8 - 5.3 the analog dikes closely propagate orthogonal to the least compressive stress σ3 and stall below the caldera rim in a circumferential arrangement. Progressive buoyancy increase through repeated supply of fluid is fundamental for the occurrence of circumferential fissures. Complementary numerical models explain the observed circumferential arrangement and validate the experiments. These results contribute defining the shallow magma transfer and related hazard assessment within calderas.

  10. Understanding the link between circumferential dikes and eruptive fissures around calderas based on numerical and analog models

    NASA Astrophysics Data System (ADS)

    Corbi, Fabio; Rivalta, Eleonora; Pinel, Virginie; Maccaferri, Francesco; Acocella, Valerio

    2016-06-01

    Active calderas are seldom associated with circumferential eruptive fissures, but eroded magmatic complexes reveal widespread circumferential dikes. This suggests that, while the conditions to emplace circumferential dikes are easily met, mechanisms must prevent them from reaching the surface. We explain this discrepancy with experiments of air injection into gelatin shaped as a volcano with caldera. Analog dikes show variable deflection, depending on the competition between overpressure, Pe, and topographic unloading, Pl; when Pl/Pe = 4.8-5.3, the dikes propagate orthogonal to the least compressive stress. Due to the unloading, they become circumferential and stall below the caldera rim; buoyancy is fundamental for the further rise and circumferential fissure development. Numerical models quantitatively constrain the stress orientation within the gelatin, explaining the observed circumferential dikes. Our results explain how dikes propagate below the rim of felsic and mafic calderas, but only in the latter they are prone to feed circumferential fissures.

  11. Medical and surgical treatment of haemorrhoids and anal fissure in Crohn’s disease: a critical appraisal

    PubMed Central

    2013-01-01

    Background The principle to avoid surgery for haemorrhoids and/or anal fissure in Crohn’s disease (CD) patients is still currently valid despite advances in medical and surgical treatments. In this study we report our prospectively recorded data on medical and surgical treatment of haemorrhoids and anal fissures in CD patients over a period of 8 years. Methods Clinical data of patients affected by perianal disease were routinely and prospectively inserted in a database between October 2003 and October 2011 at the Department of Surgery, Tor Vergata University Hospital, Rome. We reviewed and divided in two groups records on CD patients treated either medically or surgically according to the diagnosis of haemorrhoids or anal fissures. Moreover, we compared in each group the outcome in patients with prior diagnosis of CD and in patients diagnosed with CD only after perianal main treatment. Results Eighty-six CD patients were included in the study; 45 were treated for haemorrhoids and 41 presented with anal fissure. Conservative approach was initially adopted for all patients; in case of medical treatment failure, the presence of stable intestinal disease made them eligible for surgery. Fifteen patients underwent haemorrhoidectomy (open 11; closed 3; stapled 1), and two rubber band ligation. Fourteen patients required surgery for anal fissure (Botox ± fissurectomy 8; LIS 6). In both groups we observed high complication rate, 41.2% for haemorrhoids and 57.1% for anal fissure. Patients who underwent haemorrhoidectomy without certain diagnosis of CD had significantly higher risk of complications. Conclusions Conservative treatment of proctologic diseases in CD patients has been advocated given the high risk of complications and the evidence that spontaneous healing may also occur. From these preliminary results a role of surgery is conceivable in high selected patients, but definitve conclusions can’t be made. Further randomized trials are needed to establish the

  12. Monitoring of land subsidence and ground fissures in Xian, China 2005-2006: Mapped by sar Interferometry

    USGS Publications Warehouse

    Zhao, C.Y.; Zhang, Q.; Ding, X.-L.; Lu, Zhiming; Yang, C.S.; Qi, X.M.

    2009-01-01

    The City of Xian, China, has been experiencing significant land subsidence and ground fissure activities since 1960s, which have brought various severe geohazards including damages to buildings, bridges and other facilities. Monitoring of land subsidence and ground fissure activities can provide useful information for assessing the extent of, and mitigating such geohazards. In order to achieve robust Synthetic Aperture Radar Interferometry (InSAR) results, six interferometric pairs of Envisat ASAR data covering 2005-2006 are collected to analyze the InSAR processing errors firstly, such as temporal and spatial decorrelation error, external DEM error, atmospheric error and unwrapping error. Then the annual subsidence rate during 2005-2006 is calculated by weighted averaging two pairs of D-InSAR results with similar time spanning. Lastly, GPS measurements are applied to calibrate the InSAR results and centimeter precision is achieved. As for the ground fissure monitoring, five InSAR cross-sections are designed to demonstrate the relative subsidence difference across ground fissures. In conclusion, the final InSAR subsidence map during 2005-2006 shows four large subsidence zones in Xian hi-tech zones in western, eastern and southern suburbs of Xian City, among which two subsidence cones are newly detected and two ground fissures are deduced to be extended westward in Yuhuazhai subsidence cone. This study shows that the land subsidence and ground fissures are highly correlated spatially and temporally and both are correlated with hi-tech zone construction in Xian during the year of 2005-2006. ?? Springer-Verlag 2008.

  13. Three QTLs conferring resistance to kernel fissuring in rice (Oryza sativa L.) identified by selective genotyping in two tropical japonica populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kernel fissures caused by pre- or post-harvest stresses are the leading cause of breakage among milled rice, causing economic losses for producers, millers, and processors. Being an environmentally sensitive trait, it is difficult to reliably select for rice fissure resistance among breeding progen...

  14. Herpes zoster ophthalmicus presenting as orbital abscess along with superior orbital fissure syndrome: A case report.

    PubMed

    Lavaju, Poonam; Badhu, Badri Prasad; Shah, Sangeeta

    2015-09-01

    Orbital abscess and superior orbital fissure syndrome (SOFS) are rare manifestations of herpes zoster ophthalmicus. Herein, we report a case of orbital abscess along with SOFS in a 2.5-year-old-male child secondary to herpes zoster infection. He presented with a 5-day history of proptosis and ptosis of the right eye that had been preceded by vesicular eruptions on the right forehead and scalp. Computed tomography scan of the head and orbit showed orbital abscess and right cavernous sinus thrombosis. A diagnosis of orbital abscess with SOFS secondary to herpes infection was made. The condition subsequently improved following antiviral therapy, intravenous vancomycin and amikacin, and oral corticosteroids. PMID:26632131

  15. Purkinje cell age-distribution in fissures and in foliar crowns: a comparative study in the weaver cerebellum.

    PubMed

    Martí, Joaquín; Santa-Cruz, M C; Bayer, Shirley A; Ghetti, Bernardino; Hervás, José P

    2007-12-01

    Generation and settling of Purkinje cells (PCs) are investigated in the weaver mouse cerebellum in order to determine possible relationships with the fissuration pattern. Tritiated thymidine was supplied to pregnant females at the time that these neurons were being produced. Autoradiography was then applied on brain sections obtained from control and weaver offspring at postnatal (P) day 90. This makes it possible to assess the differential survival of neurons born at distinct embryonic times on the basis of the proportion of labeled cells located at the two foliar compartments: fissures and foliar crowns. Our data show that throughout the surface contour of the vermal lobes, generative programs of PCs were close between wild type and homozygous weaver. Similar data were found in the lobules of the lateral hemisphere. On the other hand, the loss of PCs in weaver cerebella can be related to foliar concavities or convexities depending on the vermal lobe or the hemispheric lobule studied. Lastly, we have obtained evidence that late-generated PCs of both normal and mutant mice were preferentially located in fissures. These quantitative relationships lead us to propose a model in which the final distribution of PCs through the vermal contour would be coupled to two factors: the cortical fissuration patterning and a "time-sequential effect" of weaver mutation.

  16. Exploring rock fissures: does a specialized root morphology explain endemism on granite outcrops?

    PubMed Central

    Poot, Pieter; Hopper, Stephen D.; van Diggelen, Josepha M.H.

    2012-01-01

    Background and Aims Worldwide, many plant species are confined to open, shallow-soil, rocky habitats. Although several hypotheses have been proposed to explain this habitat specificity, none has been convincing. We suggest that the high level of endemism on shallow soils is related to the edaphic specialization needed to survive in these often extremely drought-prone habitats. Previous research has shown that species endemic to ironstone communities in SW Australia have a specialized root morphology that enhances their chance to access fissures in the underlying rock. Here we test the generality of these findings for species that are confined to a shallow-soil habitat that is of much greater global significance: granite outcrops. Methods We compared temporal and spatial root growth and allocation of three endemic woody perennials of SW Australian granite outcrop communities with those of congeners occurring on nearby deeper soils. Seedlings of all species were grown in 1·2 m long custom-made containers with a transparent bottom that allowed monitoring of root growth over time. Key Results The granite outcrop endemics mostly differed in a predictable way from their congeners from deeper soils. They generally invested a larger portion of their biomass in roots, distributed their roots faster and more evenly over the container and had a lower specific root length. In different species pairs the outcrop endemics achieved their apparent advantage by a different combination of the aforementioned traits. Conclusions Our results are consistent with earlier work, indicating that species restricted to different types of drought-prone shallow-soil communities have undergone similar selection pressures. Although adaptive in their own habitat in terms of obtaining access to fissures in the underlying rock, these root system traits are likely to be maladaptive in deeper soil habitats. Therefore, our results may provide an explanation for the narrow endemism of many shallow

  17. Shift from magmatic to phreatomagmatic explosion controlled by the evolution of lateral fissure eruption in Suoana Crater, Miyakejima

    NASA Astrophysics Data System (ADS)

    Geshi, Nobuo; Nemeth, Karoly; Noguchi, Rina; Oikawa, Teruki

    2016-04-01

    Combined analysis of the proximal deposit and exposed feeder-diatreme structure of the Suoana Crater of Miyakejima reveals the process of magma-water interaction controlled by the evolution of lateral fissure eruption in a stratovolcanic edifice. The Suoana Crater, an oval maar with 400 x 300 m across is one of the craters of the Suoana-Kazahaya crater chain which is formed during a fissure eruption in the 7th Century. The eruption fissure extends ~3 km from the summit area (~700 m asl) to the lower-flank area (~200m asl). The eruption fissure consists of upper maar-chain (>450 m asl) and lower scora-cone chain. As the wall of the 2000 AD caldera truncated at near the center of the Suoana Crater, the vertical section of the feeder dike - diatreme - maar system of the Suoana Crater is exposed in the caldera wall (Geshi et al., 2011). The ejected materials from the Suoana crater indicate the transition of eruption style from magmatic to phreatomagmatic. The juvenile clasts in the lower half of the deposit exhibit spatter-like shape, indicating the typical deposit from a vigorous fire fountain. Contrary, the juvenile clasts in the upper half are less vesiculated and exhibit cauliflower-shape, indicating the typical phreatomagmatic activity. This transition indicates that the magma-water interaction started at the middle of the eruption. Judging from the ratio of the thickness of the lower and upper parts, the contrast of the content of juvenile clasts, and bulk density of the deposit, the total ejected volume of magma is larger in the lower part compare to the upper part. The transition from magmatic to phreatomagmatic occurred only in the upper half of the eruption fissure, including the Suoana crater, whereas the lower half of the fissure continued dry magmatic eruption throughout their activity. The limited distribution of phreatomagmatic activity can be resulted by the magma extraction from the upper feeder dike system to the lower eruption fissure as it

  18. Comparative study of Ksharasutra suturing and Lord's anal dilatation in the management of Parikartika (chronic fissure-in-ano)

    PubMed Central

    Dudhamal, Tukaram S.; Baghel, Madhav Singh; Bhuyan, Chaturbhuja; Gupta, Sanjay Kumar

    2014-01-01

    Background: Parikartika resembles fissure-in-ano which is very common among all ano-rectal disorders. In Ayurvedic texts, Parikartika is described as a complication of Vamana and Virechana as well as complication of Atisara. Ksharasutra was proved successful in the management of fistula-in-ano, piles, and there is a need to try its efficacy in fissure-in-ano. Aim: To evaluate the role of Ksharasutra suturing (KSS) in fissure bed in chronic fissure-in-ano. Materials and Methods: Total 100 patients of chronic fissure-in-ano were selected and randomly divided into two groups (50 in each group). In group-A, patients were undergone by KSS; while in patients of Group-B Lord's anal dilatation followed by KSS was done under spinal anesthesia. The KSS was done once and after slough out of Ksharasutra, the wound was treated for 4 weeks and assessment of the result was done on the basis of gradation adopted. Results: The pain relief on 14th day in Group-A was 86% while in Group-B 100% was observed. As on 7th day in Group-A, oozing was stopped in 68% patients, while in Group-B, oozing was stopped in 82% patients. On 21st day, Group-B showed more healing (85%) as compared to Group-A (69%). In this study 68% of patients were cured. Conclusion: In Group-B (KSS with Lord's anal dilatation) patients were cured early as compared to patients of Group-A (KSS alone). PMID:25558158

  19. Mechanical Behavior of Brittle Rock-Like Specimens with Pre-existing Fissures Under Uniaxial Loading: Experimental Studies and Particle Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Cao, Ri-hong; Cao, Ping; Lin, Hang; Pu, Cheng-zhi; Ou, Ke

    2016-03-01

    Joints and fissures with similar orientation or characteristics are common in natural rocks; the inclination and density of the fissures affect the mechanical properties and failure mechanism of the rock mass. However, the strength, crack coalescence pattern, and failure mode of rock specimens containing multi-fissures have not been studied comprehensively. In this paper, combining similar material testing and discrete element numerical method (PFC2D), the peak strength and failure characteristics of rock-like materials with multi-fissures are explored. Rock-like specimens were made of cement and sand and pre-existing fissures created by inserting steel shims into cement mortar paste and removing them during curing. The peak strength of multi-fissure specimens depends on the fissure angle α (which is measured counterclockwise from horizontal) and fissure number ( N f). Under uniaxial compressional loading, the peak strength increased with increasing α. The material strength was lowest for α = 25°, and highest for α = 90°. The influence of N f on the peak strength depended on α. For α = 25° and 45°, N f had a strong effect on the peak strength, while for higher α values, especially for the 90° sample, there were no obvious changes in peak strength with different N f. Under uniaxial compression, the coalescence modes between the fissures can be classified into three categories: S-mode, T-mode, and M-mode. Moreover, the failure mode can be classified into four categories: mixed failure, shear failure, stepped path failure, and intact failure. The failure mode of the specimen depends on α and N f. The peak strength and failure modes in the numerically simulated and experimental results are in good agreement.

  20. Analysis of displacements and fissure structures on a slow-moving landslide through very high-resolution orthophoto mosaicing

    NASA Astrophysics Data System (ADS)

    Rothmund, Sabrina; Joswig, Manfred; Niethammer, Uwe; Malet, Jean-Philippe

    2010-05-01

    Very high-resolution multi-temporal images with a ground resolution of a few centimeters allowed to detect and analyze displacements and fissure patterns of the Super-Sauze landslide (Southern French Alps). Images taken by an unmanned aerial vehicle (UAV) during a flight campaign in October 2008 have been used to produce a very high-resolution orthophoto-mosaic of the landslide. In this study, a set of 59 of a total of 1486 images was selected and photogrammetrically processed using different non-parametric rectification approaches (projective transformation, piecewise affine transformation and polynomial transformations of the second and third order). The generated orthophoto-mosaic covers the entire landslide area of 0.09 km² with a ground resolution of 3 to 8 cm. The comparison of this UAV-based orthophoto-mosaic with an orthophotograph from May 2007 (ground resolution of 20 cm) allowed the characterization of the horizontal displacements of the landslide. Displacement vectors were estimated by visually inspecting the images to identify distinct features (rocks, boulders and vegetation patches) in the two orthophotographs. This approach was chosen because of the high dynamics of the landslide and the disadvantageous long period between the repeated image acquisitions. Displacements between 7.1 and 55.4 m in varying directions have been detected and areas of different dynamics could be distinguished for the period between May 2007 and October 2008. Various structures, in particular fissures of different distributions and orientations, could be resolved in the UAV-based orthophoto-mosaic. The similarity of the observed fissures with glacial crevasses is striking and suggests a similar genesis. The identified longitudinal, transverse and cross-shaped fissures are linked to abrupt changes of in-situ crest orientation in the shallow subsurface. The observed shear fissures occur at the lateral boundary of emerging in-situ crests. The fissure genesis could be traced

  1. Influence of Laser Irradiation on Pits and Fissures: An In Situ Study

    PubMed Central

    Correa–Afonso, Alessandra M; Pécora, Jesus D

    2013-01-01

    Abstract Objective: The aim of this in situ study was to analyze the influence of the Er:YAG, Nd:YAG, and CO2 lasers on the enamel acid resistance of pits and fissures. Background data: The laser tissue interaction has been studied as a method of preventing occlusal caries. Methods: Thirteen volunteers wore palatal acrylic appliances containing human occlusal enamel blocks that were divided into four groups (G1, control; G2, Er:YAG; G3, Nd:YAG; G4, CO2). Each palatal acrylic appliance was used in the four studied groups and was used for 14 consecutive days. A sucrose solution was applied to the specimens six times per day. The specimens were then sectioned in half, and a microhardness test was applied. The other halves were analyzed using polarized light microscopy to measure the caries-like lesion areas, and a morphological analysis was conducted using a scanning electron microscope (SEM). Results: For the statistical analysis of the data obtained from the microhardness test (Knoop hardness number. [KHN]) (α=5%), Fisher's exact test was performed, and the group means were as follows: G1, 247±71; G2, 258±70; G3, 272±73; and G4, 298±56. The results demonstrated that the control group was significantly different from G3 and G4, which presented higher microhardness values. The Wilcoxon signed-rank test was used to analyze the data obtained from the caries-lesion area measurements (mm2) (α=5%) (G1, 0.01±1.08; G2, 0.13±0.18; G3, 0.05±0.17; and G4, 0.09±0.22). The results no showed significant differences among the groups in this analysis. Conclusions: Based on the results from the present study, it may be concluded that the CO2 and Nd:YAG lasers increased the enamel acid resistance in pits and fissures. PMID:23336742

  2. Are we following an algorithm for managing chronic anal fissure? A completed audit cycle☆

    PubMed Central

    Farkas, Nicholas; Solanki, Kohmal; Frampton, Adam E.; Black, John; Gupta, Ashish; West, Nicholas J.

    2015-01-01

    Background Anal fissure is one of the commonest proctological diseases with considerable national variation in sequential treatment. We aimed to audit our compliance of chronic anal fissure (CAF) management with national guidance provided by the Association of Coloproctology of Great Britain and Ireland (ACPGBI). Methods We retrospectively audited patients presenting to outpatient clinics with CAF over a 6-month period. Using electronic patient records, notes and clinic letters, we compared their management with ACPGBI algorithm. A prospective re-audit was then performed. Results Forty-one patients were included in the analysis (59% male). Sixty-eight percent (n = 28/41) of patients were appropriately started on conservative dietary therapy, of whom only 7.1% (n = 2/28) had treatment success. Eighty-nine percent (n = 25/28) were then appropriately treated with either topical diltiazem 2% or GTN 0.4%. Overall, 43.9% (n = 18/41) of all patients' entire management strategy adhered to the ACPGBI guidelines. In total, 48.8% (n = 20/41) patients had surgical treatment (excluding Botox), of which only 15% (n = 3/20) had undergone ACPGBI-compliant management. After local dissemination of results and education, the re-audit of 20 patients showed significant improvement in adherence to the guidelines (43.9% vs. 95%; P = 0.0001). Conclusions Topical creams were the most successful treatments (50%; n = 9/18) in ACPGBI-compliant strategies. Importantly, these data suggests that compliance with the ACPGBI algorithm leads to healing without surgery in 83.3% (n = 15/18) of patients, compared to 26.1% (n = 6/23) with non-compliant methods (P = 0.0004). This highlights the benefit of early conservative and medical management of CAF, before attempting surgery. PMID:26858833

  3. Subsurface Gas Flow and Ice Grain Acceleration within Enceladus and Europa Fissures: 2D DSMC Models

    NASA Astrophysics Data System (ADS)

    Tucker, O. J.; Combi, M. R.; Tenishev, V.

    2014-12-01

    The ejection of material from geysers is a ubiquitous occurrence on outer solar system bodies. Water vapor plumes have been observed emanating from the southern hemispheres of Enceladus and Europa (Hansen et al. 2011, Roth et al. 2014), and N2plumes carrying ice and ark particles on Triton (Soderblom et al. 2009). The gas and ice grain distributions in the Enceladus plume depend on the subsurface gas properties and the geometry of the fissures e.g., (Schmidt et al. 2008, Ingersoll et al. 2010). Of course the fissures can have complex geometries due to tidal stresses, melting, freezing etc., but directly sampled and inferred gas and grain properties for the plume (source rate, bulk velocity, terminal grain velocity) can be used to provide a basis to constrain characteristic dimensions of vent width and depth. We used a 2-dimensional Direct Simulation Monte Carlo (DSMC) technique to model venting from both axi-symmetric canyons with widths ~2 km and narrow jets with widths ~15-40 m. For all of our vent geometries, considered the water vapor source rates (1027­ - 1028 s-1) and bulk gas velocities (~330 - 670 m/s) obtained at the surface were consistent with inferred values obtained by fits of the data for the plume densities (1026 - 1028 s-1, 250 - 1000 m/s) respectively. However, when using the resulting DSMC gas distribution for the canyon geometries to integrate the trajectories of ice grains we found it insufficient to accelerate submicron ice grains to Enceladus' escape speed. On the other hand, the gas distributions in the jet like vents accelerated grains > 10 μm significantly above Enceladus' escape speed. It has been suggested that micron-sized grains are ejected from the vents with speeds comparable to the Enceladus escape speed. Here we report on these results including comparisons to results obtained from 1D models as well as discuss the implications of our plume model results. We also show preliminary results for similar considerations applied to Europa

  4. Overview of the 2012-13 basaltic fissure eruption of Tolbachik, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynetz, Anna; Melnikov, Dmitry; Senyukov, Sergey

    2014-05-01

    On 27 November 2012 a short-lived swarm of shallow (<10 km) earthquakes marked the onset of a new eruption from the Tolbachik volcanic complex, in east-central Kamchatka, Russia. The 3.5-km-long radial eruptive fissure opened on the south flank between 1500-2000 m a.s.l. Lava fountaining from multiple small vents ceased after several days and the eruption continued from vents at the southern end of the fissure. Almost continuous lava fountains up to 200 m high issued from a small lava lake located inside the broad, open crater of the largest cinder cone. While explosive activity was rather mild, initial discharge of lava was very high (up to 400 m3/s) and by the end of December 'a'a lava flows had travelled up to 17 km from the vent. SiO2 concentrations for the plagioclase-phyric lava were 54 wt.%, but then decreased to 52 wt.%. In January 2013 lava was transported through a system of lava tubes 1 km long and up to 5 m wide. From tube exit points it propagated in the form of channelized lava streams (velocities 1-3 m/s; discharge rates 30-50 m3/s); on lower slopes of the volcano it propagated mostly as 'a'a flows. Lava channels were frequently dammed by floating clinker and accretionary lava balls, which caused flooding of proximal areas by ropy/shelly/slabby pahoehoe lavas. Locally small volumes of lava were extruded through the upper surfaces and lateral levees of 'a'a lava to form very slowly inflating entrail pahoehoe lava lobes. Starting in mid-February the average intensity of the eruption gradually declined, with sporadic bursts in February and April. By May discharge rates of lava had decreased to approximately 15 m3/s and most of lava started to flow as entrail pahoehoe. By the beginning of June the volume of erupted products (dominantly lavas) reached 0.52km3. The effusion of lava continued until the end of August, when the lava lake in the crater of the active cinder cone became inactive. Weak strombolian outbursts from 1-3 small vents on the bottom of

  5. Location of seismic events and eruptive fissures on the Piton de la Fournaise volcano using seismic amplitudes

    USGS Publications Warehouse

    Battaglia, J.; Aki, K.

    2003-01-01

    We present a method for locating the source of seismic events on Piton de la Fournaise. The method is based on seismic amplitudes corrected for station site effects using coda site amplification factors. Once corrected, the spatial distribution of amplitudes shows smooth and simple contours for many types of events, including rockfalls, long-period events and eruption tremor. On the basis of the simplicity of these distributions we develop inversion methods for locating their origins. To achieve this, the decrease of the amplitude as a function of the distance to the source is approximated by the decay either of surface or body waves in a homogeneous medium. The method is effective for locating rockfalls, long-period events, and eruption tremor sources. The sources of eruption tremor are usually found to be located at shallow depth and close to the eruptive fissures. Because of this, our method is a useful tool for locating fissures at the beginning of eruptions.

  6. The 'Jack Stone' or 'Mercedes Benz' sign--anew theory to explain the presence of gas within fissures in gallstones.

    PubMed

    Wright, F W

    1977-07-01

    Gas within clefts of fissures in gallstones is not a very common finding, but when it occurs is, characteristic and indicates the presence of one or more calculi. It closely resembles the appearance of a 'Jack Stone' but has previously been termed the 'Mercedes Benz' sign. Only a few cases have previously been recognised in the U.K. Most reported cases have been associated with biliary colic or cholecystitis. Various theories have been put forward to explain the presence of gas, but the author believes that the gas is released from solution by negative pressure within cholesterol stones undergoing internal fissuring due to their crystalline structure, i.e. the gas is released from solution from the small amount of fluid trapped in the calculus, in the same way that gas may be 'pulled' out of solution in a joint, a degenerate intervertebral disc or the fibro-cartilage of the symphysis pubis.

  7. The 'Jack Stone' or 'Mercedes Benz' sign--anew theory to explain the presence of gas within fissures in gallstones.

    PubMed

    Wright, F W

    1977-07-01

    Gas within clefts of fissures in gallstones is not a very common finding, but when it occurs is, characteristic and indicates the presence of one or more calculi. It closely resembles the appearance of a 'Jack Stone' but has previously been termed the 'Mercedes Benz' sign. Only a few cases have previously been recognised in the U.K. Most reported cases have been associated with biliary colic or cholecystitis. Various theories have been put forward to explain the presence of gas, but the author believes that the gas is released from solution by negative pressure within cholesterol stones undergoing internal fissuring due to their crystalline structure, i.e. the gas is released from solution from the small amount of fluid trapped in the calculus, in the same way that gas may be 'pulled' out of solution in a joint, a degenerate intervertebral disc or the fibro-cartilage of the symphysis pubis. PMID:872516

  8. An Experimental Study of the Fracture Coalescence Behaviour of Brittle Sandstone Specimens Containing Three Fissures

    NASA Astrophysics Data System (ADS)

    Yang, S. Q.; Yang, D. S.; Jing, H. W.; Li, Y. H.; Wang, S. Y.

    2012-07-01

    To analyse the fracture coalescence behaviour of rock, rectangular prismatic sandstone specimens (80 × 160 × 30 mm in size) containing three fissures were tested under uniaxial compression. The strength and deformation behaviours of the specimens are first analysed by investigating the effects of the ligament angle β2 on the peak strength, peak strain and crack initiation stress of the specimens. To confirm the sequence of crack coalescence, a photographic monitoring technique is used throughout the entire period of deformation. Based on the results, the relationship between the real-time crack coalescence process and the axial stress-strain curve of brittle sandstone specimens is also developed, and this relationship can be used to evaluate the macroscopic deformation characteristics of pre-cracked rock. The equivalent strain evolution fields of the specimen, with α = β1 = 45° and β2 = 90°, are obtained using the digital image correlation technique and show good agreement with the experimental results of pre-cracked brittle sandstone. These experimental results are expected to improve the understanding of fracture mechanisms and be used in rock engineering with intermittent structures, such as deep underground excavated tunnels.

  9. Modeling the hydraulical behavior of a fissured-karstic aquifer in exploitation conditions

    NASA Astrophysics Data System (ADS)

    Debieche, T. H.; Guglielmi, Y.; Mudry, J.

    2002-02-01

    A 5-year daily measurement of the dynamic level in a borehole was plotted versus cumulative yield since the beginning of exploitation. Eighty percent of the experimental curve is explained by a linear function ( h= aQc+ h0) by intervals. Only floods, which follow heavy storms and non-pumping cannot be taken into account. The slopes of the straight lines are spread around two constant values of the slope: a r=+0.35×10 -3 m m -3, which characterizes the part which is controlled by recharge, and a p=-0.14× 10 -3 m m -3, which characterizes the draining part of the aquifer fractures. This linear fitting demonstrates that the borehole-aquifer system can be considered as an equivalent continuous medium, where the linear relationship between dynamic head and pumped yield are defined by the values of ar and ap. Thus the hydraulic behavior of the aquifer differs according to the pumping rate: equivalent continuous medium for a low rate, dual permeability for a high one. This work demonstrates that the long-term behavior of an exploited fissured aquifer can be described by a simple model, if the duration of the aquifer test is long enough (1-3 months). It also shows that the production phase must include repetitive head measurements in order to refine the exploitation yield and the management conditions.

  10. Evidence for Bacterial Sulfate Reduction in a Fissured-porous Karst System in Southern Germany

    NASA Astrophysics Data System (ADS)

    Einsiedl, F.; Mayer, B.

    2005-12-01

    Twenty five percent of the world's population uses karst water as drinking water resources. Since karst groundwater systems are highly vulnerable to contamination, groundwater protection and self purification is a major challenge. Up to now research in karst groundwater systems has predominantly concentrated on hydrodynamic processes. Little is known about anoxic processes in oxygen dominated, fracture-matrix diffusion controlled karst aquifers. Isotope measurements comprise a promising tool to identify biogeochemical processes such as bacterial (dissimilatory) sulfate reduction in karstic aquifers. The goal of this study was to determine the sources and the processes affecting sulfate in an oxygen-rich karst aquifer in southern Germany and their dependence on hydrogeological parameters. This was achieved by interpreting tritium data with a simple lumped parameter approach and assessing variations in concentrations and isotopic compositions of sulfate and dissolved inorganic carbon (DIC) with respect to groundwater age. Young groundwater (<30 years) was characterized by comparatively high sulfate concentrations (0.36 mM) and δ34S values similar to those of recent atmospheric deposition (1.5‰). In contrast groundwater with mean residence times >60 years had significantly lower sulfate concentrations (0.08 mM) and markedly higher δ34S values (7.5‰). These results indicate that in karst systems with matrix porosity, bacterial (dissimilatory) sulfate reduction may occur. This process has the potential to contribute to long-term biodegradation of contaminants in the porous rock matrix representing the dominant water reservoir in fissured-porous karst aquifers.

  11. A randomized control clinical trial of fissure sealant retention: Self etch adhesive versus total etch adhesive

    PubMed Central

    Aman, Nadia; Khan, Farhan Reza; Salim, Aisha; Farid, Huma

    2015-01-01

    Context: There are limited studies on comparison of Total etch (TE) and Self etch (SE) adhesive for placement of sealants. Aims: The aim of the study was to compare the retention of fissure sealants placed using TE adhesive to those sealants placed using SE (seventh generation) adhesive. Settings and Design: The study was conducted in the dental section, Aga Khan University Hospital. This study was a randomized single blinded trial with a split mouth design. Materials and Methods: The study included 37 patients, 101 teeth were included in both study groups. The intervention arm was treated with SE Adhesive (Adper Easy One, 3M ESPE, US). Control arm received TE adhesive (Adper Single Bond 2, 3M ESPE, US) before sealant application. The patients were followed after 6 months for assessment of sealant retention. Statistical analysis used: Interexaminer agreement for outcome assessment was assessed by Kappa Statistics and outcome in intervention group was assessed by McNemar's test. Results: Ninety-one pairs of molar (90%) were reevaluated for sealant retention. Complete retention was 56% in TE arm and 28% in SE arm with an odds ratio (OR) of 3.7. Conclusions: Sealants applied with TE adhesives show higher rate of complete sealant retention than SE adhesive. PMID:25657521

  12. Sylvian fissure and parietal anatomy in children with autism spectrum disorder.

    PubMed

    Knaus, Tracey A; Tager-Flusberg, Helen; Foundas, Anne L

    2012-01-01

    Autism spectrum disorder (ASD) is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF) and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7-14 years), matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions. PMID:22713374

  13. Hemorrhoids, anal fissure, and carcinoma of the colon, rectum, and anus during pregnancy.

    PubMed

    Medich, D S; Fazio, V W

    1995-02-01

    The pregnant patient afflicted with a variety of colorectal conditions merits special consideration for reasons related to the safety and timeliness of operation while preserving fetal viability and fertility. The literature is scanty with respect to hemorrhoids, fissures, and colorectal and anal carcinoma. Therefore, the patient has to have a forthright discussion with her physician(s) about the pros and cons of operative and nonoperative approaches, which can result in either therapeutic abortion and timely surgery versus preserving the fetus and taking on the unknown factor of whether delay in treatment will cause an adverse outcome. This underscores the need for a frank discussion with the patient with regard to anticipated outcomes. In benign conditions, there is more latitude to adopt a conservative approach, as the patient's ability to tolerate the symptoms of her condition would dictate the need for definitive operative therapy. In the patient with malignancy, delaying surgical or radiation therapy carries an unknown risk to the patient. Here, the patient's personal views regarding abortion and future fertility dictate the timing of definitive treatment.

  14. Chabazite in spodumene-bearing Alpine-type fissure veins from Hiddenite, North Carolina, USA

    NASA Astrophysics Data System (ADS)

    Wise, Michael A.

    2009-07-01

    Alpine-type fissure vein mineralization in the Hiddenite area of western North Carolina, USA consists mostly of quartz, but locally contains Cr-bearing beryl (emerald) or Cr-bearing spodumene (hiddenite). These gem minerals occur in mineral-lined cavities and may be accompanied by euhedral crystals of quartz, calcite, muscovite, rutile, albite, pyrite, siderite and dolomite. Chabazite-Ca occurs as a late stage phase in spodumene-bearing veins, but is absent in emerald-bearing veins. Chabazite-Ca occurs as simple penetrating twins of pseudocubic rhombohedra and as the lens-shaped variety, phacolite. Chabazite-Ca from Hiddenite contains minor amounts of Na, Mg, Fe and K. Phacolitic chabazite-Ca shows Fe-enriched but Mg-depleted cores relative to the rims. Chemical zoning is absent in rhombohedral chabazite. The Hiddenite chabazite apparently precipitated under low temperature (< 250°C) and low pressure (< 2 kbar) conditions during the waning stages of crystallization of an alkaline hydrothermal fluid.

  15. Hemorrhoids, anal fissure, and carcinoma of the colon, rectum, and anus during pregnancy.

    PubMed

    Medich, D S; Fazio, V W

    1995-02-01

    The pregnant patient afflicted with a variety of colorectal conditions merits special consideration for reasons related to the safety and timeliness of operation while preserving fetal viability and fertility. The literature is scanty with respect to hemorrhoids, fissures, and colorectal and anal carcinoma. Therefore, the patient has to have a forthright discussion with her physician(s) about the pros and cons of operative and nonoperative approaches, which can result in either therapeutic abortion and timely surgery versus preserving the fetus and taking on the unknown factor of whether delay in treatment will cause an adverse outcome. This underscores the need for a frank discussion with the patient with regard to anticipated outcomes. In benign conditions, there is more latitude to adopt a conservative approach, as the patient's ability to tolerate the symptoms of her condition would dictate the need for definitive operative therapy. In the patient with malignancy, delaying surgical or radiation therapy carries an unknown risk to the patient. Here, the patient's personal views regarding abortion and future fertility dictate the timing of definitive treatment. PMID:7855720

  16. Clinical evaluation of the retention and wear of a light-cured pit and fissure glass ionomer sealant.

    PubMed

    Aranda, M; Garcia-Godoy, F

    1995-01-01

    The purpose of this study was to evaluate the 12-month retention and wear of an experimental light-cured glass ionomer for pit and fissure sealing. A total of 25 patients 7-14 years-old were selected from the Pediatric Dentistry Clinic at the University of Texas Health Science Center at San Antonio. The patients resided in areas without fluoridated water. Each tooth was isolated with cotton rolls, dried with oil-free compressed air and GC Dentin Conditioner applied with a small disposable brush to the pits and fissures for 20 seconds. The teeth were rinsed with water and gently air dried using an air/water syringe. The teeth were not desiccated. GC experimental glass ionomer for pit and fissures was used. The powder/liquid ratio was dispensed at 1.4 gm/1.0 gm (one level spoonful of powder to one drop of liquid). The powder was mixed for 15-20 seconds. An explorer was used to apply the mixed sealant to the tooth and teased into all pits and fissures. The sealant was then cured for 20 seconds. Occlusion was corrected after the sealant was light-cured. Immediately, a color slide and a vinyl polysiloxane impressions were taken. The impressions were poured in epoxy resin. Color slides, impressions and epoxy models were also made at 3, 6, 9 and 12-month recalls. A total of 95 sealants were placed and follow-up for 12 months. The results showed that with the clinical visual inspection all sealants were present at 3 and 6 months postoperatively. At 12 months, only 20% of the sealants were clinically evident.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7547485

  17. Probable recent water/lava source fissures in the Cerberus Plains: stratigraphic and crater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, R.

    2012-09-01

    The Cerberus Plains have received increasing attention in recent years due to evidence from highresolution imagery that they are some of the youngest surfaces on Mars. The plains are incised by large outflow channels, possibly as recently as 20Ma in the case of Athabasca Valles [2]. These channels are generally thought to be water-carved [1,3], though it is possible they were incised by turbulent lava [8]. As recently as 10Ma or less [5] both the channels and the plains around them are proposed to have been draped with lava [7]. Thus the recent activity forming the Cerberus Plains probably required large volumes of both water and lava. The problem which arises is a source. Cerberus Fossae have been suggested as the source of the Athabasca Valles outflows [3,6], but topographic and stratigraphic issues have arisen which make this unlikely: for example, a streamlined island spans the fossa where water and/or lava is said to have originated [4]. No other specific sources have been identified. As plains volcanism often obscures its fissures, sources should be searched for in features elevated above the plain. New HiRISE images have shown just such a feature: a wrinkle ridge south of Cerberus Fossae incised by a series of fissures. Every fissure has associated channels and deposits indicating outflow onto the plains surrounding the ridge. Until now, the stratigraphic history of these features was poorly known, with Tanaka et al.'s [9] geological map considering the area only on the broadest scale. This study produces small-scale geomorphological maps to establish the stratigraphic relationships between the fissure-sourced outflows and the plains surrounding the ridge to test the hypothesis that they were the source of the plains material. Crater counting is also conducted to supplement stratigraphic observations and give tentative ages.

  18. An anatomical structure which results in puffiness of the upper eyelid and a narrow palpebral fissure in the Mongoloid eye.

    PubMed

    Yuzuriha, S; Matsuo, K; Kushima, H

    2000-09-01

    The typical Mongoloid eye differs from the Occidental one in puffiness of the upper eyelid and narrowness of the palpebral fissure. We surmised that an anatomical structure might exist in the preaponeurotic fat space, which determines the features of the Mongoloid eye. The upper eyelids of 720 Japanese patients and eight Japanese cadavers were macroscopically investigated, and sagittal slices of the central upper eyelid of one patient and nine cadavers were microscopically analysed. Another, lower-positioned transverse ligament different from the higher-positioned Whitnall's one was identified just above the fusional line between the orbital septum and the levator aponeurosis in almost every upper eyelid. A robust ligamentous structure was observed in 331 patients (46%) with puffier eyelids and a narrower palpebral fissure, a diaphanous retinaculum in 381 patients (53%) and no transverse ligamentous tissue in eight patients (1%). Histological evaluation demonstrated that this ligament was composed of tight bundles of collagen fibres containing few elastic fibres. Examination of the preaponeurotic fat space indicated that the superficial expansion of the levator aponeurosis turned up around this transverse ligament to become the orbital septum. When the levator muscle contracts, the deep expansion of the levator aponeurosis retracts the tarsus, the middle expansion retracts the pretarsal orbicularis oculi muscle and skin, and the superficial expansion retracts the preaponeurotic fat against this ligament. This structure thus determines the low position of the preaponeurotic fat and restricts the vertical width of the palpebral fissure, causing the features of the Mongoloid eye.

  19. Cellular resolution optical access to brain regions in fissures: Imaging medial prefrontal cortex and grid cells in entorhinal cortex

    PubMed Central

    Low, Ryan J.; Gu, Yi; Tank, David W.

    2014-01-01

    In vivo two-photon microscopy provides the foundation for an array of powerful techniques for optically measuring and perturbing neural circuits. However, challenging tissue properties and geometry have prevented high-resolution optical access to regions situated within deep fissures. These regions include the medial prefrontal and medial entorhinal cortex (mPFC and MEC), which are of broad scientific and clinical interest. Here, we present a method for in vivo, subcellular resolution optical access to the mPFC and MEC using microprisms inserted into the fissures. We chronically imaged the mPFC and MEC in mice running on a spherical treadmill, using two-photon laser-scanning microscopy and genetically encoded calcium indicators to measure network activity. In the MEC, we imaged grid cells, a widely studied cell type essential to memory and spatial information processing. These cells exhibited spatially modulated activity during navigation in a virtual reality environment. This method should be extendable to other brain regions situated within deep fissures, and opens up these regions for study at cellular resolution in behaving animals using a rapidly expanding palette of optical tools for perturbing and measuring network structure and function. PMID:25503366

  20. Morphologic Study of Superior Temporal Sulcus-Amygdaloid Body and Lateral Fissure-Amygdaloid Body Surgical Approach by Using Magnetic Resonance Imaging Volume Rendering.

    PubMed

    Qu, Yuan; Ren, Bichen; Chang, Xiaoyu; Zhang, Jinnan; Li, Youqiong; Duan, Haobo; Cheng, Kailiang; Wang, Jincheng

    2016-01-01

    In this research, 83 patients were measured by magnetic resonance imaging volume rendering technique. The authors acquired the curve length of the superior temporal sulcus and the lateral fissure on the cerebral hemisphere, the shortest distance from the superior temporal sulcus and the lateral fissure to the center of amygdaloid body separately, the vertical diameter, the transversal diameter, and the anteroposterior diameter of the amygdaloid body and the 2 approach angles between the median sagittal plane and the shortest segment from the superior temporal sulcus to the center of amygdaloid body and the shortest segment from lateral fissure to the center of the amygdaloid body. At the same time, we preliminarily oriented the 2 points of the superior temporal sulcus and the lateral fissure, which are closest to the center of amygdaloid body, aimed at finding out the best entrance points of surgical approach through the superior temporal sulcus and the lateral fissure to the amygdaloid body and reducing the damage to the nerve fibers or blood vessels during the operation. The results indicate that the point at the front side 1/4 of the superior temporal sulcus may be the ideal surgical approach entrance point and the point at the front side 1/3 of the lateral fissure. There is no difference between 2 cerebral hemispheres (P < 0.05).

  1. Drivers of explosivity and elevated hazard in basaltic fissure eruptions: The 1913 eruption of Ambrym Volcano, Vanuatu (SW-Pacific)

    NASA Astrophysics Data System (ADS)

    Németh, Károly; Cronin, Shane J.

    2011-04-01

    Fissure-eruptions along linear structures can extend for several tens of kilometres with distinct separate manifestations of volcanism along their length. They typically involve low-viscosity mafic magmas forming long lava flows and cinder cones. Eruptions in 1894 and 1913 on Ambrym volcano, Vanuatu, showed how these mildly explosive eruptions can rapidly transform into violent explosive events, producing significant hazard and widespread volcanic ash clouds. During the 1913 episode, a fissure began in the central caldera and basaltic magmas broke out in a series of locations down the island's western flank. In all sites over 100 m in elevation, fissure outbreaks produced vigorous lava fountains and highly fluid lava flows that travelled rapidly to the shoreline. When the outbreaks propagated along the island's axis into coastal plain areas, a climactic series of explosive eruptions occurred, producing a 1.2 km long by 600 m wide maar and tephra ring. A further small tuff ring was formed later, creating a temporary island 400 m offshore. The onshore tephra ring destroyed a hospital and associated buildings. Its last evacuating occupants were close witnesses to the eruption processes. Deposits exposed in the lower portion of the tephra ring show that this part of the eruption began with a mild phreatomagmatic explosive eruption from a narrow vent, followed by a magmatic scoria-producing phase. Subsequently a complex sequence of highly explosive phreatomagmatic eruptions occurred, producing pyroclastic surges, along with repeated distinctive breccia-horizons, rich in coral and lava country rock. These features tally with eye-witness accounts to indicate that the main eruption phase was produced by a periodically shifting locus of phreatomagmatic fragmentation and eruption along a single E-W fissure. The glassy and vesicle-poor pyroclasts produced during this eruption phase were dominantly fragmented in a brittle manner by magma water interaction. Low volatile content

  2. Recrystallized Granite Surface Fissures Of The Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith L.

    2000-05-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, namely, Mount Tuscarora-Wolverine-Millicent,^1,6,7 Bonanza Peak-Midway,^2 Little Cottonwood Canyon and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atmosphere interface, establish that they resulted from high thermal gradients rather than passages of earthquake waves. Magma chambers formed, solidified during Permo-Caroniferous Ice Age(roughly, 1/3...1/4 billion yr ago, a time interval preceding period of extrusion of Rocky Mountains, 10^8 yr ago), and while fluid, belched lava flows^5 extending over its reservoir walls to run hundred of meters. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface so that a pluton containing large amounts of dross(Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.^3 Such recrystallized fissures, reaching depths of perhaps 100 m, have initial fractures near time of solidification of their uppermost portion of magma chamber while still hot(<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, cold water contacts due to rain, stream flow over granite surface, partial coverage by ocean, etc., wherever heat sinks might occur, during P-C ice age--when region of Wasatch Range existed at sea level, Salt Lake Valley being covered entirely by ocean water and region east of Wasatch Bouleuard rising gently above Pacific Ocean to elevations of possibly 500-1000 ft, say, at a distance of 10-15 mi to east. This fact is implied by Chinese Wall of white limestone on Grandeur Peak, unequivocally, and similarly another in Neff's Canyon running e. from n. ridge of 9200 ft. saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in Salt Lake Valley. This existed prior to regional

  3. Identification of possible recent water/lava source fissures in the Cerberus Plains: stratigraphic and crater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    The Cerberus plains are one of the youngest surfaces on Mars. They are thought to have been formed by lava and/or water flows, but there is considerable debate regarding the source of this material. Much of the material forming the western plains, including the Athabasca Valles outflow channels, appears to have flowed from the region of the Cerberus Fossae graben system [1,2,3] and limited areas forming the eastern plains may have been erupted by low shield volcanoes [4,5]. However, flow of material from west to east is obstructed by a ridge centred on 157°E, 7°N and, prior to this study, vents which might be the source of fluid of a low enough viscosity to form the majority of the flat eastern plains had not been identified. We studied new HiRISE (25cm/px, High Resolution Science Imaging Experiment) images of the ridge between the east and west plains and observed possible source vents for this material: the ridge is cut by a series of pits and fissures which lie at the heads of flows and channels extending towards the surrounding plains. In order to establish the stratigraphic relationships between the vents and plains, this study produced large scale geomorphological maps based on the HiRISE images. The mapping showed that both incised channels and leveed flows extend onto the plain to the south of the ridge and that these were the final phase of plains-forming activity in that region. Conversely, to the north, ridge-sourced deposits only form the plains surface close to the ridge - beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, a large-scale flow which does not emanate from this ridge forms the plains surface, but there is evidence that the youngest outflow activity from the ridge was contemporaneous with emplacement of this unit. We also performed crater counts to age-date the surfaces and these indicate that plains-forming and ridge-sourced units are of a

  4. Characterisation and microleakage of a new hydrophilic fissure sealant - UltraSeal XT® hydro™

    PubMed Central

    GÜÇLÜ, Zeynep A.; DÖNMEZ, Nazmiye; HURT, Andrew P.; COLEMAN, Nichola J.

    2016-01-01

    ABSTRACT Objectives The aim of this study was to characterise the new hydrophilic fissure sealant, UltraSeal XT® hydro™ (Ultradent Products, USA), and to investigate its in vitro resistance to microleakage after placement on conventionally acid etched and sequentially lased and acid etched molars. Material and Methods The sealant was characterised by Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Vickers indentation test. Occlusal surfaces of extracted human molars were either conventionally acid etched (n=10), or sequentially acid etched and laser irradiated (n=10). UltraSeal XT® hydro™ was applied to both groups of teeth which were then subjected to 2,500 thermocycles between 5 and 55°C prior to microleakage assessment by fuchsin dye penetration. Results UltraSeal XT® hydro™ is an acrylate-based sealant that achieved a degree of conversion of 50.6±2.2% and a Vickers microhardness of 24.2±1.5 under standard light curing (1,000 mWcm-2 for 20 s). Fluoride ion release is negligible within a 14-day period. SEM and EDX analyses indicated that the sealant comprises irregular submicron and nano-sized silicon-, barium-, and aluminium-bearing filler phases embedded in a ductile matrix. Laser preconditioning was found to significantly reduce microleakage (Mann-Whitney U test, p<0.001). The lased teeth presented enhanced surface roughness on a 50 to 100 μm scale that caused the segregation and concentration of the filler particles at the enamel-sealant interface. Conclusion Laser preconditioning significantly decreased microleakage and increased enamel surface roughness, which caused zoning of the filler particles at the enamel-sealant interface. PMID:27556205

  5. [Epidemiology of anal lesions (fissure and thrombosed external hemorroid) during pregnancy and post-partum].

    PubMed

    Abramowitz, L; Batallan, A

    2003-06-01

    Thrombosed external hemorrhoids (TEH) and anal fissure (AF) are 2 frequent sources of anal pains during childbirth. We are going to define their incidences as available in publications and in our experience in Bichat hospital. Then we will define their risk factors. According to Martin's and Corby's studies, AF was observed in 10% of the delivered women. In Bichat hospital we performed a proctological assessment to 165 pregnant women during the last third of pregnancy and within the 2 months following delivery. We observed 2 AF (1,2%) during the first period and 25 (15,2%) during the second. Rouillon et al. reported an incidence of TEH in 12,2% (20/164), while Pradel and al. reported 34% (18/52) of it. In Bichat hospital, 13 women (7,9%) were presenting with TEH during the last third of pregnancy and 33 (20%) in post-partum period. Two studies looked for a statistical correlation between AF and obstetrical, foetal or maternal factors. Corby et al. only pointed the role of constipation. In our study, terminal constipation was the most important risk factor for AF with 5.7 (2.7-12), odds ratio (95% confidence intervals). Rouillon et al. observed more TEH among women with a prolonged first stage labor and a big baby. In our study, a big baby and mother little lips tears were observed more often among women with TEH (P <0,05). Also, we observed only one TEH among the 25 women with caesarean section (4%). Finally, observation that TEH arise immediately after delivery is another argument to support the role of traumatic delivery. We also demonstrated the role of terminal constipation as risk factor for TEH after delivery. To conclude, 1/3 of pregnant women develop AF or TEH after delivery. These 2 pathologies are strongly correlated to terminal constipation. TEH seems equally furthered by traumatic delivery. PMID:12865195

  6. Stratigraphy, paleoenvironment and emplacement mechanisms of the Koko fissure craters, O'ahu, Hawai'i

    NASA Astrophysics Data System (ADS)

    Skilling, I. P.; Bluth, J.; Simoneau, E.

    2011-12-01

    The Koko fissure craters are aligned and nested basanitic tuff cones and rings at the SE corner of O'ahu, Hawai'i. There are no published studies of their stratigraphy, emplacement mechanisms or depositional paleoenvironments. This study focuses on a tuff cone complex (Koko Crater) and a younger adjacent nested tuff ring (Hanauma Bay). A detailed stratigraphy with logged sections for both Koko Crater and the Hanauma Bay craters are presented and discussed. Koko Crater is dominated by wet fallout deposits on steep proximal slopes, commonly resedimented by hot (vesiculated) and cold (unvesiculated) debris flows, slumps and slides, but with an increasing percentage of wet (low temperature) low concentration PDC deposits preserved in the shallowly-dipping flanking apron deposits, and in the uppermost proximal deposits. At least two earlier cone or ring rims are preserved along its southern margin. The deposits of Hanauma Bay overlie the Koko deposits and are dominated by a mix of wet low concentration PDC, wet fallout and synchronous PDC, and fallout deposits in proximal settings, and by low concentration, probably drier, PDC deposits in more distal settings. The Hanauma Bay rings were emplaced before the Koko Crater tephra was consolidated, as steep-sided rills incised into Koko tephra are locally filled with tephra of mixed Koko and Hanauma sources. The onset of Hanauma Bay eruptions is marked by a horizon that is very rich in rounded coral sand clasts. Discontinuous horizons and lenses of coral block fallout are also very common in the Hanauma tephra. Coral sand is absent and coral blocks are much rarer in the Koko tephra. These observations, and probably also the dominance of wet fallout at Koko, imply that Koko was erupted in deeper water than the nearshore coral beach environment of the Hanauma rings. A faster rate of water recharge into the conduit in deeper open water is probably the most important factor in the generation of a cone rather than a ring at this

  7. Effects of sealant, viscosity, and bonding agents on microleakage of fissure sealants: An in vitro study

    PubMed Central

    Mehrabkhani, Maryam; Mazhari, Fatemeh; Sadeghi, Samaneh; Ebrahimi, Masoumeh

    2015-01-01

    Objective: The aim of this study was to evaluate the effects of enamel or dentin bonding agent (DBA) and sealant viscosity on sealant microleakage. Materials and Methods: Sixty extracted human premolars were randomly divided into two equal groups (based on sealant viscosity) and each group was divided into three subgroups of 10 teeth. Group 1 (low viscosity sealant, Seal-Rite, Pulpdent, USA with 7.7% filler): Prophylaxis, enameloplasty, etching of occlusal surfaces with 38% of phosphoric acid gel, rinsing and drying, followed by (1) enamel bonding agent (EBA) (Margin Bond, Coltène/Whaledent AG) or (2) DBA (Excite, Ivoclar Vivadent AG, Liechtenstein) or (3) no bonding (NB) prior to sealant application. In Group 2, similar procedures were performed except for applying a high viscosity sealant (Seal-Rite, Pulpdent, The USA with 34.4% filler). Specimens were thermocycled and then immersed in a 0.5% basic fuchsine solution for 24 h next, buccolingual slices of samples were scored under a stereomicroscope. The Kruskal–Wallis and Mann–Whitney U-tests were used for data analysis. Results: There was no significant difference between DBA, EBA, and NB subgroups in the microleakage scores in both groups. Low viscosity sealant had a lower microleakage than the high viscosity sealant in both DBA (P = 0.002) and NB (P = 0.041) subgroups. Conclusion: The results indicated that the use of low viscosity sealant reduced the microleakage of pit and fissure sealants. However, the use of a bonding agent before sealant placement didn’t affect the microleakage. PMID:26929696

  8. Measurements of the gas emission from Holuhraun volcanic fissure eruption on Iceland, using Scanning DOAS instruments

    NASA Astrophysics Data System (ADS)

    Galle, Bo; Pfeffer, Melissa; Arellano, Santiago; Bergsson, Baldur; Conde, Vladimir; Barsotti, Sara; Stefansdottir, Gerdur; Ingvarsson, Thorgils; Bergsson, Bergur; Weber, Konradin

    2016-04-01

    On 31 August 2014 a volcanic fissure eruption started at Holuhraun on Iceland. The eruption lasted for 6 months and was by far the strongest source of sulfur dioxide in Europe over the last 230 years, with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affected people within Iceland. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions was developed. Since the first day of the eruption several of these novel instruments were monitoring the SO2 emission from the eruption. A lot of work was needed to sustain this operation during the winter at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions has required the development of novel methods to derive reliable flux estimates. A simple approach to make a first order correction for atmospheric scattering has been applied, as well as filtering of the dataset to remove the data most affected by scattering. Substantial work has also been made to obtain realistic information on plume height and wind speed. The data from these instruments are the only sustained ground-based measurements of this important gas emission event. In this presentation we will discuss the instrumental issues and evaluation procedures and present the latest version of the emission estimates made from our measurements.

  9. Earth-Fissure Movements Associated with Fluctuations in Ground-Water Levels near the Picacho Mountains, South-Central Arizona, 1980-84

    USGS Publications Warehouse

    Carpenter, M.C.

    1993-01-01

    The Picacho earth fissure transects subsiding alluvial sediments near the east periphery of the Picacho basin in south-central Arizona. The basin has undergone land subsidence of as much as 3.8 meters since the 1930's owing to compaction of the aquifer system in response to ground-water-Ievel declines that have exceeded 100 meters. The fissure, which extends generally north-south for 15 kilometers, exhibits horizontal tensile failure and as much as 0.6 meter of normal dip-slip movement at the land surface. The west side of the fissure is down thrown. The fissure was observed as early as 1927 and is the longest earth fissure in Arizona. Vertical and horizontal displacements were monitored along a line normal to the fissure. The survey line extends from a bedrock outcrop in the Picacho Mountains on the east, past an observation well near the fissure, to a point 1,422 meters to the west. From May 1980 to May 1984, the downthrown west side of the fissure subsided 167+-1.8 millimeters and moved 18+-1.5 millimeters westward into the basin. Concurrently, the relatively upthrown east side subsided 148+-1.8 millimeters and moved 14+-1.5 millimeters westward. Dislocation modeling of deformation along the survey line near the fissure indicates that dip-slip movement has occurred along a vertical fault surface that extends from the land surface to a depth of about 300 meters. Slip was 9 millimeters from May to December 1980 and also 9 millimeters from March to November 1981. Continuous measurements were made of horizontal movement across the fissure using a buried invar-wire horizontal extensometer, while water-level fluctuations were continuously monitored in four piezometers nested in two observation wells. The range of horizontal movement was 4.620 millimeters, and the range of water-level fluctuation in the nearest piezometer in the deep alluvium was 9.05 meters. The maximum annual opening of the fissure during the study period was 3.740 millimeters from March to October

  10. Recrystallized Granite Surface Fissures of Wasatch Range Produced Not Later Than 1/4Billion Years Ago

    NASA Astrophysics Data System (ADS)

    McDonald, Keith

    2000-11-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M, (K.L. McDonald, Bul. A.P.S., 32 (4), 1124),(37 (5), 1256-7),(38 (1), 740) Bonanza Pk.-Midway,(35 (9), 2132) Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab that they resulted from high thermal gradients and not passages of earthquake waves.(33 (9), 1982-2) Magma chambers formed, solidified during Permo- Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion, pf Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows(36 (9), 2466) extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock(38 (1), 740) to reach Earth's surface, so that a pluton containing large amounts of dross (Fe ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure.(33 (3), 485) Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<< 1600 ^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age -- when region of Wasatch Range existed at sea level, S.L. Valley being covered entrely by ocean water and region of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a dist. of 10-15 mi to e, as implied by Chinese Wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w., in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an

  11. Origins of Feeding Arteries of Hepatocellular Carcinoma Located Near the Umbilical Fissure of the Left Hepatic Lobe: Angiographic Evaluation

    SciTech Connect

    Miyayama, Shiro Yamashiro, Masashi; Shibata, Yoshihiro; Hashimoto, Masahiro; Yoshida, Miki; Tsuji, Kazunobu; Toshima, Fumihito; Matsui, Osamu

    2012-12-15

    Purpose: To analyze the origins of the feeding arteries of hepatocellular carcinomas (HCCs) near the umbilical fissure of the left hepatic lobe. Methods: Twenty-eight HCCs with a mean {+-} SD tumor diameter of 3.4 {+-} 1.0 cm (range 1-4.4 cm) in contact with the right or left side of the umbilical fissure were treated by superselective transcatheter arterial chemoembolization (TACE). The origins of the tumor-feeding arteries were analyzed with arteriograms and computed tomography or cone-beam computed tomography images obtained during and 1 week after TACE.ResultsTwenty-one HCC lesions were located in segment 3 and seven were located in segment 4. Of 21 tumors in segment 3, 13 (61.9%) were supplied by the lateral inferior subsegmental artery (A3), three (14.3%) by the medial subsegmental artery (A4), three (14.3%) by both A4 and A3, one (4.8%) by a branch arising from the left lateral hepatic artery, and one (4.8%) by a branch of the right gastric artery. In particular, all tumor-feeding branches arising from A4 were the first branch of A4. Of seven tumors in segment 4, four (57.1%) were supplied by A4 and three (42.9%) by A3. In particular, all tumor-feeding branches arising from A3 were the first branch of A3. Conclusion: This study demonstrates crossover blood supply to HCC lesions located near the umbilical fissure, in addition to direct feeding from a separate branch. In particular, the first branch of the opposite subsegmental artery may feed tumors when crossover blood supply is present.

  12. Dyke propagation mechanisms and the immediate pre- and syn-eruptive seismicity of the 2014 Holuhraun fissure eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Woods, Jennifer; Ágústsdóttir, Thorbjörg; Greenfield, Tim; Green, Robert G.; White, Robert S.; Brandsdóttir, Bryndís; Steinthórsson, Sveinbjörn; Redfern, Simon

    2015-04-01

    We present data from our dense seismic array which captured the micro-seismicity associated with the propagating dyke intrusion from the subglacial Bárðarbunga volcano, during the 24 hours preceding and following the onset of effusive magmatism at the Holuhraun lava field in central Iceland. The Bárðarbunga volcano is located at the centre of the Iceland hot spot within the Eastern Rift Zone, beneath the Vatnajökull ice cap. Local magmatic intrusions can be tracked through the swarms of micro-seismicity accompanying dyke propagation, arising from crustal failure and fracture of both the country rock and solidifying magma plugs. August 2014 saw the beginning of a period of unrest of Bárðarbunga volcano during which a dyke propagated first out of the caldera and then towards the northeast. It continued north of the Dyngjujökull outlet glacier and resulted in a fissure eruption in the old Holuhraun lava field on 29 August 2014. At time of writing it has erupted ~1km3 of lava covering over 64km2, making this the largest eruption in Iceland for 150 years. Our extensive, local seismic network covers the numerous volcanic systems beneath the Vatnajökull glacier and their transecting fissure swarms (rifting units) along the divergent plate boundary. This work focusses on the immediate pre- and syn-eruptive seismicity of the 2014 Holuhraun fissure eruption. Rock fracture mechanisms are determined from fault plane solutions of these seismic events, produced as the magma migrated from beneath the surface to the eruption site.

  13. Are eruptions from linear fissures and caldera ring dykes more likely to produce pyroclastic flows?

    NASA Astrophysics Data System (ADS)

    Jessop, D. E.; Gilchrist, J.; Jellinek, A. M.; Roche, O.

    2016-11-01

    Turbulent volcanic jets are produced by highly-energetic explosive eruptions and may form buoyant plumes that rise many tens of kilometres into the atmosphere to form umbrella clouds or collapse to generate ground-hugging pyroclastic flows. Ash injected into the atmosphere can be transported for many hundreds of kilometres with the potential to affect climate, disrupt global air travel and cause respiratory health problems. Pyroclastic flows, by contrast, are potentially catastrophic to populations and infrastructure close to the volcano. Key to which of these two behaviours will occur is the extent to which the mechanical entrainment and mixing of ambient air into the jet by large (entraining) eddies forming the jet edge changes the density of the air-ash mixture: low entrainment rates lead to pyroclastic flows and high entrainment rates give rise to buoyant plumes. Recent experiments on particle-laden (multi-phase) volcanic jets from flared and straight-sided circular openings suggest that the likelihood for buoyant plumes will depend strongly on the shape and internal geometry of the vent region. This newly recognised sensitivity of the fate of volcanic jets to the structure of the vent is a consequence of a complex dynamic coupling between the jet and entrained solid particles, an effect that has generally been overlooked in previous studies. Building on this work, here we use an extensive series of experiments on multi-phase turbulent jets from analogue linear fissures and annular ring fractures to explore whether the restrictive vent geometry during cataclysmic caldera-forming (CCF) eruptions will ultimately lead a relatively greater frequency of pyroclastic flows than eruptions from circular vents on stratovolcanoes. Our results, understood through scaling analyses and a one-dimensional theoretical model, show that entrainment is enhanced where particle motions contribute angular momentum to entraining eddies. However, because the size of the entraining

  14. The fissured East Yorkshire Chalk, UK - a 'sustainable' aquifer under stress ?

    NASA Astrophysics Data System (ADS)

    Elliot, T.; Younger, P. L.; Chadha, D. S.

    2003-04-01

    The fissured Chalk is an important regional aquifer in East Yorkshire, UK, with a large potential for water supply to the Humberside region and especially the City of Hull. It has been exploited since the end of the 19th Century, but although there are more than a dozen long-established pumping wells in the Chalk these currently abstract only 7% of the total recharge the aquifer receives. The classical notion of ‘safe aquifer yield' equates the quantity of groundwater available for abstraction with the long-term natural recharge to the aquifer. An incautious hydrogeologist might be lead to conclude that this is a secure, under-developed resource. In this case study, the aquifer is shown to be already displaying early symptoms of hydrological stress (eg drought effects, overexploitation), and hydrogeochemical indicators point to further effects of anthropogenic pollution impacts in the unconfined aquifer and both recent and ancient saline intrusion in its semi-confined and confined zones. The hydrochemical evidence clearly reveals the importance both of recent aquifer management decisions and palaeohydrogeology in determining the distribution of water qualities within the aquifer. Waters encountered in the confined aquifer are identified as complex (and potentially dynamic) mixtures between recently recharged waters, modern seawater intrusion, and ancient seawater which entered the aquifer many millennia ago. Elliot, T. Younger, P.L. &Chadha, D.S. (1998) The future sustainability of groundwater resources in East Yorkshire - past and present perspectives. In H. Wheater and C. Kirby (Eds.) Hydrology in a Changing Environment, Vol. II, Proc. British Hydrological Society (BHS) International Conference, 6-10 July 1998, Exeter, UK. pp.21-31. Elliot, T., Chadha, D.S. &Younger, P.L. (2001) Water Quality Impacts and Palaeohydrogeology in the East Yorkshire Chalk Aquifer, UK. Quarterly Journal of Engineering Geology and Hydrogeology, 34(4): 385-398. Younger, P.L., Teutsch

  15. CHEMICAL TRANSPORT IN A FISSURED BOCK: VERIFICATION OF A NUMERICAL MODEL

    SciTech Connect

    Rasmuson, A.; Narasimhan, T.N.; Neretnieks, I.

    1982-04-01

    Numerical models for simulating chemical transport in fissured rocks constitute powerful tools for evaluating the acceptability of geological nuclear waste repositories. Due to the very long-term, high toxicity of some nuclear waste products, the models are required to predict, in certain cases, the spatial and temporal distribution of chemical concentration less than 0.001% of the concentration released from the repository. Whether numerical models can provide such accuracies is a major question addressed in the present work. To this end, we have verified a numerical model, TRUMP, which solves the advective diffusion equation in general three dimensions with or without decay and source terms. The method is based on an integrated finite-difference approach. The model was verified against known analytic solution of the one-dimensional advection-diffusion problem as well as the problem of advection-diffusion in a system of parallel fractures separated by spherical particles. The studies show that as long as the magnitude of advectance is equal to or less than that of conductance for the closed surface bounding any volume element in the region (that is, numerical Peclet number <2), the numerical method can indeed match the analytic solution within errors of ±10{sup -3} % or less. The realistic input parameters used in the sample calculations suggest that such a range of Peclet numbers is indeed likely to characterize deep groundwater systems in granitic and ancient argillaceous systems. Thus TRUMP in its present form does provide a viable tool for use in nuclear waste evaluation studies. A sensitivity analysis based on the analytic solution suggests that the errors in prediction introduced due to uncertainties in input parameters is likely to be larger than the computational inaccuracies introduced by the numerical model. Currently, a disadvantage in the TRUMP model is that the iterative method of solving the set of simultaneous equations is rather slow when time

  16. Chemical Transport in a Fissured Rock: Verification of a Numerical Model

    NASA Astrophysics Data System (ADS)

    Rasmuson, A.; Narasimhan, T. N.; Neretnieks, I.

    1982-10-01

    Numerical models for simulating chemical transport in fissured rocks constitute powerful tools for evaluating the acceptability of geological nuclear waste repositories. Due to the very long-term, high toxicity of some nuclear waste products, the models are required to predict, in certain cases, the spatial and temporal distribution of chemical concentration less than 0.001% of the concentration released from the repository. Whether numerical models can provide such accuracies is a major question addressed in the present work. To this end we have verified a numerical model, TRUMP, which solves the advective diffusion equation in general three dimensions, with or without decay and source terms. The method is based on an integrated finite difference approach. The model was verified against known analytic solution of the one-dimensional advection-diffusion problem, as well as the problem of advection-diffusion in a system of parallel fractures separated by spherical particles. The studies show that as long as the magnitude of advectance is equal to or less than that of conductance for the closed surface bounding any volume element in the region (that is, numerical Peclet number <2), the numerical method can indeed match the analytic solution within errors of ±10-3% or less. The realistic input parameters used in the sample calculations suggest that such a range of Peclet numbers is indeed likely to characterize deep groundwater systems in granitic and ancient argillaceous systems. Thus TRUMP in its present form does provide a viable tool for use in nuclear waste evaluation studies. A sensitivity analysis based on the analytic solution suggests that the errors in prediction introduced due to uncertainties in input parameters are likely to be larger than the computational inaccuracies introduced by the numerical model. Currently, a disadvantage in the TRUMP model is that the iterative method of solving the set of simultaneous equations is rather slow when time

  17. Increased anal basal pressure in chronic anal fissures may be caused by overreaction of the anal-external sphincter continence reflex.

    PubMed

    van Meegdenburg, Maxime M; Trzpis, Monika; Heineman, Erik; Broens, Paul M A

    2016-09-01

    Chronic anal fissure is a painful disorder caused by linear ulcers in the distal anal mucosa. Even though it counts as one of the most common benign anorectal disorders, its precise etiology and pathophysiology remains unclear. Current thinking is that anal fissures are caused by anal trauma and pain, which leads to internal anal sphincter hypertonia. Increased anal basal pressure leads to diminished anodermal blood flow and local ischemia, which delays healing and leads to chronic anal fissure. The current treatment of choice for chronic anal fissure is either lateral internal sphincterotomy or botulinum toxin injections. In contrast to current thinking, we hypothesize that the external, rather than the internal, anal sphincter is responsible for increased anal basal pressure in patients suffering from chronic anal fissure. We think that damage to the anal mucosa leads to hypersensitivity of the contact receptors of the anal-external sphincter continence reflex, resulting in overreaction of the reflex. Overreaction causes spasm of the external anal sphincter. This in turn leads to increased anal basal pressure, diminished anodermal blood flow, and ischemia. Ischemia, finally, prevents the anal fissure from healing. Our hypothesis is supported by two findings. The first concerned a chronic anal fissure patient with increased anal basal pressure (170mmHg) who had undergone lateral sphincterotomy. Directly after the operation, while the submucosal anesthetic was still active, basal anal pressure decreased to 80mmHg. Seven hours after the operation, when the anesthetic had completely worn off, basal anal pressure increased again to 125mmHg, even though the internal anal sphincter could no longer be responsible for the increase. Second, in contrast to previous studies, recent studies demonstrated that botulinum toxin influences external anal sphincter activity and, because it is a striated muscle relaxant, it seems reasonable to presume that it affects the striated

  18. The temperature and width of an active fissure on Enceladus measured with Cassini VIMS during the 14 April 2012 South Pole flyover

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, Bonnie J.; Brown, Robert H.; Clark, Roger N.; Nicholson, Phillip D.; Hedman, Matthew M.; Howell, Robert R.; Sotin, Christophe; Cruikshank, Dale P.; Baines, Kevin H.; Lawrence, Kenneth J.; Spencer, John R.; Blackburn, David G.

    2013-09-01

    The width and temperature of the active fissures on Saturn’s satellite Enceladus provide key observable constraints on physical models of these geyser-like eruptions. We analyze a sequence of high spatial resolution near-infrared spectra acquired with VIMS at 0.025 s intervals during a 74 km altitude flyover of the South Pole of Enceladus by the Cassini spacecraft on 14 April 2012 UTC. A thermal-emission spectrum covering 3- to 5-μm wavelengths was detected as the field of view crossed one of the four major fissures, Baghdad Sulcus, within 1 km of 82.36S latitude and 28.24W longitude. We interpret this spectrum as thermal emission from a linear fissure with temperature 197 ± 20 K and width 9 m. At the above wavelengths, the spectrum is dominated by the warmest temperature component. Looking downward into the fissure at only 13° from the vertical, we conclude that our results measure the temperature of the interior fissure walls (and the H2O vapor) at depths within 40 m of the surface.

  19. Fissural volcanism, polygenetic volcanic fields, and crustal thickness in the Payen Volcanic Complex on the central Andes foreland (Mendoza, Argentina)

    NASA Astrophysics Data System (ADS)

    Mazzarini, F.; Fornaciai, A.; Bistacchi, A.; Pasquarè, F. A.

    2008-09-01

    Shield volcanoes, caldera-bearing stratovolcanoes, and monogenetic cones compose the large fissural Payen Volcanic Complex, located in the Andes foreland between latitude 35°S and 38°S. The late Pliocene-Pleistocene and recent volcanic activity along E-W trending eruptive fissures produced basaltic lavas showing a within-plate geochemical signature. The spatial distribution of fractures and monogenetic vents is characterized by self-similar clustering with well defined power law distributions. Vents have average spacing of 1.27 km and fractal exponent D = 1.33 defined in the range 0.7-49.3 km. The fractal exponent of fractures is 1.62 in the range 1.5-48.1 km. The upper cutoffs of fractures and vent fractal distributions (about 48-49 km) scale to the crustal thickness in the area, as derived from geophysical data. This analysis determines fractured media (crust) thickness associated with basaltic retroarc eruptions. We propose that the Payen Volcanic Complex was and is still active under an E-W crustal shortening regime.

  20. Native gold from volcanic gases at Tolbachik 1975-76 and 2012-13 Fissure Eruptions, Kamchatka

    NASA Astrophysics Data System (ADS)

    Chaplygin, Ilya; Yudovskaya, Marina; Vergasova, Lidiya; Mokhov, Andrey

    2015-12-01

    Aggregates and euhedral crystals of native gold were found in sublimates formed during New Tolbachik Fissure Eruption in 2012-2013 (NTFE). Gold-bearing sublimate samples were taken from a red-hot (690 °C) degassing fracture in the roof of an active lava tunnel 1.5 km from active Naboko cinder cone in May 2013. The gas condensate collected at 690 °C in this site contains 16 ppb Au, 190 ppb Ag and 1180 ppm Cu compared to 3 ppb Au, 39 ppb Ag and 9.7 ppm Cu in the condensate of pristine magmatic gas sampled at 1030 °C. The 690 °C volcanic gas is most likely a mix of magmatic gas and local snow buried under the lava flows as indicated by oxygen and hydrogen isotope compositions of the condensate. The lower-temperature gas enrichment in gold, copper and chlorine is resulted from evaporation of the 690 °C condensate during forced gas pumping at sampling. Native gold was also found in fumarolic encrustations collected from caverns in basalt lava flows with temperature up to 600 °C in June 2014, in a year after eruption finished. The native gold precipitation in newly formed Cu-rich sublimates together with the well known gold occurrences in cinder cones of 1975-1976 Large Tolbachik Fissure Eruption manifest a transport capability of oxidized volcanic gas.

  1. A Modified LBM Model for Simulating Gas Seepage in Fissured Coal Considering Klinkenberg Effects and Adsorbability-Desorbability

    NASA Astrophysics Data System (ADS)

    Tan, Yun-Liang; Teng, Gui-Rong; Zhang, Ze

    2010-01-01

    A modified Lattice-Boltzmann method is proposed by considering the Klinkenberg effect and adsorbability-desorbability for the purpose of simulating methane gas seepage in fissured coal. The results show that the Klinkenberg effect has a little influence on methane gas seepage in fissured coal, so it can be neglected in engineering computations for simplicity. If both the Klinkenberg effect and the adsorbability-desorbability are considered, the Klinkenberg influence on gas pressure decreases as the Darcy coefficient increases. It is found by gas drainage simulations that near a drainage hole, the effect of adsorption and desorption cannot be neglected, and the location of the drainage hole has a great influence on drainage efficient λ when the hole is just located at the mid-zone of the coal seam, λ is 0.691808; when the hole is excursion down to 1.0 m from the mid-zone of coal seam, λ decreases to 0.668631; when the hole is excursion up or down to 2.0 m from the mid-zone of coal seam, λ decreases to 0.632917. The simulations supply an effective approach for optimizing the gas drainage hole location.

  2. Microtensile bond strength of a resin-based fissure sealant to Er,Cr:YSGG laser-etched primary enamel.

    PubMed

    Sungurtekin-Ekci, Elif; Oztas, Nurhan

    2016-05-01

    The aim of this study was to evaluate the effect of Er,Cr:YSGG laser pre-treatment alone, or associated with acid-etching, on the microtensile bond strength of a resin-based fissure sealant to primary enamel. Twenty-five human primary molars were randomly divided into five groups including (1) 35 % acid etching, (2) 2.5-W laser etching, (3) 3.5-W laser etching, (4) 2.5-W laser etching + acid etching, and (5) 3.5-W laser etching + acid etching. Er,Cr:YSGG laser was used at a wavelength of 2.780 nm and pulse duration of 140-200 μs with a repetition rate of 20 Hz. Following surface pre-treatment, the fissure sealant (ClinPro™, 3M Dental Products) was applied. Each tooth was sectioned and subjected to microtensile testing. Kruskal-Wallis test was used for statistical analysis. The level of significance was set at p < 0.05. The microtensile bond strength values of group 1 were significantly higher than those of group 2, while no statistically significant difference was detected between groups 1, 3, 4, and 5. It was concluded that 3.5-W laser etching produced results comparable to conventional acid etching technique, whereas 2.5-W laser etching was not able to yield adequate bonding performance.

  3. Recrystallized Granite Surface Fissures Of Wasatch Range, Produced Not Later Than 1/4 Billion Years Ago.

    NASA Astrophysics Data System (ADS)

    McDonald, K. L.

    2002-04-01

    Our studies of numerous recrystallized fissures in 4 granite plutons of Wasatch Range, i.e., Mount T-W-M^1,6,7 Bonanza Pk.-Midway,^2 Little Cottonwood and Ferguson Canyon plutons, all of which formed magma chambers reaching Earth-atm. interface, estab. that they resulted from high thermal gradients and not passages of earthquake waves.^4 Magma chambers formed, solidified during Permo-Carboniferous Ice Age (roughly 1/3...1/4 billion yr ago), a time interval preceding extrusion of Rocky Mts., 10^8 yr ago, and while fluid, some belched lava flows^5 extending over its reservoir walls to run hundreds of m. We have shown how the magma melts, dilutes and replaces overlying metamorphic rock^7 to reach Earth's surface, so that a pluton containing large amounts of dross (Fe-ores, etc.) had a short fluid lifetime. We also described how offshoots from a long-running main fissure form acute angles with that fissure^3. Recryst. fissures, reaching depths of perhaps 100 m, had initial fractures near time of solidification of top portion of magma chamber, while still hot (<= 1600^oF), a time when max. stresses occur near granite surface due to high thermal gradients, owing to snow coverage, rain water, stream flow over granite surface, partial coverage by ocean, etc., during P-C ice age - when region of Wasatch Range existed at sea level, S. L. Valley being covered entirely by ocean water and region east of Wasatch Boul. rising gently above Pac. Ocean to elev. of possibly 500-1000 ft, say, at a distance of 10-15 mi to e, as implied by Chinese wall of limestone on Grandeur Pk, another in Neff's Canyon running e from n ridge of her 9200 ft saddle-summit, as well as a dozen other ancient calcified stream beds emptying into ocean to w, in S.L. Valley. This existed prior to regional uplift (of similar topog.) of over 4000 ft. Details of how earthquake waves form an epicenter from which propagate 2 stress fields in diam. opp. directions to open up, by a few m, surface granite to form a

  4. Comparison of Clinical Success of Applying a Kind of Fissure Sealant on the Lower Permanent Molar Teeth in Dry and Wet Conditions

    PubMed Central

    Eskandarian, Tahereh; Baghi, Saeid; Alipoor, Abbas

    2015-01-01

    Statement of the Problem Fissure sealant therapy is among the most effective methods of preventing dental caries. However, it is lengthy and isolation of the teeth is difficult in this procedure especially in young children. Using new hydrophilic fissure sealant may reduce such problems. Purpose This study aimed to evaluate the clinical success of a hydrophilic fissure sealant on the lower permanent molar teeth in dry and wet conditions. Materials and Method This clinical trial assessed 31 patients (mean age 8.13±1.77 years) who needed fissure sealant therapy on their first or second mandibular permanent molar. Having performed dental prophylaxis, the teeth were etched and rinsed. Then one of the two was randomly selected and sealed with smartseal & loc in isolated and dry conditions; while, the other was wetted on the etched enamel by using a saliva-contaminated micro brush, and was then sealed with the same fissure as the first tooth. Six and 12 months later, two independent observers examined the clinical success of sealant through checking the marginal integrity, marginal discoloration, and anatomical form. Data were analyzed by using SPSS software, version 16. The bivariate Chi-square and Exact Fisher tests were used to compare the clinical success of the two treatment methods. Results There was a high interpersonal reliability between the two examiners (K= 0.713). After 12 months, 90.3% clinical success was observed in dry conditions and 83.9% in wet conditions for smartseal & loc; however, the difference was not statistically significant (p= 0.0707). Conclusion According to the results of this study, it seems that using new hydrophilic fissure sealant can reduce technical sensitivities and consequently decreases the apprehensions on saliva contamination of etched enamel during treatment procedures. PMID:26331144

  5. The ‘Excess’ Emission from the Warm Surface Adjacent to Active Fissures on Enceladus from Combined VIMS and CIRS Spectra

    NASA Astrophysics Data System (ADS)

    Goguen, Jay D.; Buratti, Bonnie J.; Howell, Robert R.

    2015-11-01

    The exciting discovery of thermal emission from the tiger stripe fissures at the S. pole of Enceladus is a major highlight of the Cassini mission. Both VIMS (Visible and Infrared Mapping Spectrometer) and CIRS (Composite InfraRed Spectrometer) detect the thermal ‘blackbody’ spectrum emitted from the warm fissure areas. The VIMS instrument is uniquely suited to measuring the hottest active locations because VIMS covers the 3 to 5 micron wavelength range where the rising edge of the Planck function for these T~200 K areas dominates the emission spectrum. At longer wavelengths, the spectrum is more complicated because contributions from small hot areas and larger cooler areas combine to form the broad emission spectrum that is detected by the CIRS instrument at wavelengths >6.7 microns. It is the combination of VIMS and CIRS spectra that paint a more complete portrait of the fissure heat transfer processes. Using spectra that span both the VIMS and CIRS wavelengths places a stronger constraint on the T distribution near the fissures than consideration of the spectra from either instrument alone.We show that when the best (= highest spatial resolution, 800 m/pixel and smaller) VIMS and CIRS spectra of the fissure thermal emission are considered together, there is a large (up to 400%) component of ‘excess’ emission spanning 7 to 17 microns that requires explanation. New analysis of ~2 km spatial resolution VIMS spectra of the Damascus hot spot on 8/13/2010 are similar to the highest resolution 4/14/2012 VIMS Baghdad spectra, confirming that differences in location or time between the best VIMS and CIRS spectra do not explain away the excess. The obvious interpretation is that there are processes that transfer heat from the fissure eruption to the surface within 400 m of the fissure center in addition to heat conduction through the fissure walls. Candidate heat transfer processes include fallback of large warm low velocity ice particles from the edges of the

  6. Mechanisms, Monitoring and Modeling Earth Fissure generation and Fault activation due to subsurface Fluid exploitation (M3EF3): A UNESCO-IGCP project in partnership with the UNESCO-IHP Working Group on Land Subsidence

    NASA Astrophysics Data System (ADS)

    Teatini, P.; Carreon-Freyre, D.; Galloway, D. L.; Ye, S.

    2015-12-01

    Land subsidence due to groundwater extraction was recently mentioned as one of the most urgent threats to sustainable development in the latest UNESCO IHP-VIII (2014-2020) strategic plan. Although advances have been made in understanding, monitoring, and predicting subsidence, the influence of differential vertical compaction, horizontal displacements, and hydrostratigraphic and structural features in groundwater systems on localized near-surface ground ruptures is still poorly understood. The nature of ground failure may range from fissuring, i.e., formation of an open crack, to faulting, i.e., differential offset of the opposite sides of the failure plane. Ground ruptures associated with differential subsidence have been reported from many alluvial basins in semiarid and arid regions, e.g. China, India, Iran, Mexico, Saudi Arabia, Spain, and the United States. These ground ruptures strongly impact urban, industrial, and agricultural infrastructures, and affect socio-economic and cultural development. Leveraging previous collaborations, this year the UNESCO Working Group on Land Subsidence began the scientific cooperative project M3EF3 in collaboration with the UNESCO International Geosciences Programme (IGCP n.641; www.igcp641.org) to improve understanding of the processes involved in ground rupturing associated with the exploitation of subsurface fluids, and to facilitate the transfer of knowledge regarding sustainable groundwater management practices in vulnerable aquifer systems. The project is developing effective tools to help manage geologic risks associated with these types of hazards, and formulating recommendations pertaining to the sustainable use of subsurface fluid resources for urban and agricultural development in susceptible areas. The partnership between the UNESCO IHP and IGCP is ensuring that multiple scientific competencies required to optimally investigate earth fissuring and faulting caused by groundwater withdrawals are being employed.

  7. Overview of the precursors and dynamics of the 2012-13 basaltic fissure eruption of Tolbachik Volcano, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Belousov, Alexander; Belousova, Marina; Edwards, Benjamin; Volynets, Anna; Melnikov, Dmitry

    2015-12-01

    We present a broad overview of the 2012-13 flank fissure eruption of Plosky Tolbachik Volcano in the central Kamchatka Peninsula. The eruption lasted more than nine months and produced approximately 0.55 km3 DRE (volume recalculated to a density of 2.8 g/cm3) of basaltic trachyandesite magma. The 2012-13 eruption of Tolbachik is one of the most voluminous historical eruptions of mafic magma at subduction related volcanoes globally, and it is the second largest at Kamchatka. The eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5-10 km; its apical part contained 54-55 wt.% SiO2, and the main body 52-53 wt.% SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of > 440 m3/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian-Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 m3/s and formed a compound lava field with a total area of ~ 36 km2; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. Based on a broad array of new data collected during this eruption, we develop a model for the magma storage and transport system of Plosky Tolbachik that links the storage zones of the two main genetically related magma

  8. Assessing the atmospheric and climatic effects of basaltic fissure eruptions. A case study Nornahraun, North Iceland, 2014-2015.

    NASA Astrophysics Data System (ADS)

    Gallagher, Catherine; Burton, Kevin; Thordarson, Thorvaldur; Vye-Brown, Charlotte; Brown, Richard

    2015-04-01

    A volcanic eruption's ability to release sulphur gases into the atmosphere is one of the critical factors in assessing their climatic and environmental effects, because it is directly linked to the potential H2SO4 aerosol burden produced [1]. Basaltic fissure eruptions loft large amounts of sulphur into the atmosphere because of the efficient degassing of volatiles and halogens from the magma at the vent [2-4] coupled with the high sulphur yield of basaltic magma. The common nature of this style of eruption and its products, regardless of magnitude, means that our understanding of the exact processes which influence atmospheric chemistry and environmental impact is very important. The Nornahraun fissure eruption in North Iceland that began on the 31st August 2014, has quickly become one of the best documented eruptions of its kind, through systematic monitoring and sampling by the Institute of Earth Sciences eruption team and The Icelandic Meteorological Office. As a result it is an excellent modern analogue for historic or ancient basaltic fissure eruptions, for which the amount of degassing can only be estimated through petrological and geochemical methods. It also serves as a timely testing platform for novel geochemical proxies. This study uses the exceptional sensitivity of the 187Os-187Re radiogenic system to the presence of crustal material [5], and highly siderophile stable isotopes Cu, Zn and S to indicate the chemistry and degassing of the melt carrying S to the surface. The geochemical isotopic proxies will be tested using established petrological methods and gas emission data. This study concentrates on determining the following key parameters: (1) The source of volatiles in the magma indicated though the pressure dependence of S solubility. (2) The mechanism of aerosol and gas release into the atmosphere is dictated both by the chemistry of the melt that controls the S species (H2S, SO2 or FeS2) present [6], and by the mechanism of transfer. (3) The

  9. Microbial diversity in endostromatolites (cf. Fissure Calcretes) and in the surrounding permafrost landscape, Haughton impact structure region, Devon Island, Canada.

    PubMed

    Pellerin, André; Lacelle, Denis; Fortin, Danielle; Clark, Ian D; Lauriol, Bernard

    2009-11-01

    In recent years, endostromatolites, which consist of finely laminated calcite columns that grow orthogonally within millimeter- to centimeter-thick fissures in limestone bedrock outcrops, have been discovered in dolomitic outcrops in the Haughton impact structure region, Devon Island, Canada. The growth mechanism of the endostromatolites is believed to be very slow and possibly intertwined with biotic and abiotic processes. Therefore, to discern how endostromatolites form in this polar desert environment, the composition of the microbial community of endostromatolites was determined by means of molecular phylogenetic analysis and compared to the microbial communities found in the surrounding soils. The microbial community present within endostromatolites can be inferred to be (given the predominant metabolic traits of related organisms) mostly aerobic and chemoheterotrophic, and belongs in large part to the phylum Actinobacteria and the subphylum Alphaproteobacteria. The identification of these bacteria suggests that the conditions within the fissure were mostly oxidizing during the growth of endostromatolite. The DNA sequences also indicate that a number of bacteria that closely resemble Rubrobacter radiotolerans are abundant in the endostromatolites as well as other Actinobacteria and Alphaproteobacteria. Some of these taxa have been associated with calcite precipitation, which suggests that the endostromatolites might in fact be microbially mediated. Bacterial communities from nearby permanently frozen soils were more diverse and harbored all the phyla found in the endostromatolites with additional taxa. This study on the microbial communities preserved in potentially microbially mediated secondary minerals in the Arctic could help in the search for evidence of life-forms near the edge of habitability on other planetary bodies.

  10. Knowledge, value, opinion and practice about usage of pit and fissure sealant among dental professionals in Chennai, Tamil Nadu, India

    PubMed Central

    Nagappan, N.; Dhamodhar, M. Dinesh; Nithin, M. G.; Kumar, E. Senthil

    2015-01-01

    Aim: A study was aimed to assess the knowledge, value, opinion, and practice regarding the use of dental sealants among private dental practitioners in Chennai, Tamil Nadu, India. Materials and Methods: A self-administrated questionnaire were distributed to 192 private dental practitioners in Chennai, Tamil Nadu, India by using simple random sampling. A convenience sampling technique was employed. The questionnaire consisted of 28 items, which included information about knowledge, value, opinion, and practice regarding dental sealants. The questionnaire was obtained from the study by San Martin et al. 2013 and Kailash Asawa et al. 2014. Frequency distribution was tabulated. For frequency distribution strongly, strongly agree, and agree were combined as “agree” and strongly disagree and disagree were combined as “disagree.” There were no changes in “neutral.” Results: Among the 196 study subjects 56.2% were males and 43.8% were females with their clinical experience of 52.1% for <5 years, 35.4% for 5–10 years, and 13.5% for >15 years. The mean scores for knowledge, value, opinion, and practice were 41.8 ± 3.7, 18.7 ± 2.8, 18.1 ± 1.4, and 12.9 ± 2.3, respectively. Conclusion: The results suggest that dental practitioners had satisfactory knowledge about pit and fissure sealant and had neutral attitudes about sealants being effective. Dental practitioners adequately used the pit and fissure sealants but they did not follow the standardized procedures and specific guidelines. PMID:26942116

  11. Dike Propagation Mechanisms from Seismicity Accompanying the 2014 Bárðarbunga-Holuhraun Fissure Eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Woods, J.; Ágústsdóttir, T.; Greenfield, T. S.; Green, R. G.; White, R. S.; Brandsdottir, B.

    2015-12-01

    We present data from our dense seismic network which captured in unprecedented detail the micro-seismicity associated with the 2014 dike intrusion from the subglacial Bárðarbunga volcano in central Iceland. Over 30,000 automatically located earthquakes delineate a complex 46 km dike propagation during the days preceding the onset of effusive magmatism at the Holuhraun lava field on 29 August 2014. Approximately 1.5 km3 of lava was erupted, making this the largest eruption in Iceland for over 200 years.Micro-seismicity tracks the lateral migration of the dike, with a concentration of earthquakes in the advancing tip where stresses are greatest, and trailing zones of lesser or no seismicity behind. Onset of an initial 4 hour fissure eruption was accompanied simultaneously by a backward retreat in seismic activity, followed by a gradual re-advance prior to the onset of a second, sustained fissure eruption in the same location on 31 August. Rock fracture mechanisms are determined from fault plane solutions of these seismic events. At the tip of the advancing dike, left-lateral strike-slip faulting parallel to the propagation is dominant, utilising pre-existing lineations and releasing stress accumulated in the brittle layer from rift zone extension. Behind the dike tip, both right-lateral and left-lateral strike-slip earthquakes are found, marking failure of solidifying magma plugs within the dike conduit. Contrary to many models of dike propagation, both normal faulting and failure at high angles to the dike are rare. Furthermore, a distinct lack of seismicity is observed in the 3-4 km region beneath the surface rupture. This suggests that opening is occuring aseismically, with earthquakes focused at the base of the dike near the brittle-ductile boundary.

  12. Microleakage and penetration depth of three types of materials in fissure sealant: self-etching primer vs etching: an in vitro study.

    PubMed

    Gillet, D; Nancy, J; Dupuis, V; Dorignac, G

    2002-01-01

    Clinical preventive procedures must be done after a risk assessment. One of the risk factors is the occlusal morphology of the posterior teeth. These caries-free fissures must be sealed. This first in vitro experimentation of the study evaluated the microleakage and the penetration depth of three types of materials by Vivadent: Helioseal F, Tetric, Tetric Flow. The teeth were etched with phosphoric acid and bonded using a one bottle bonding in order to determine the best material for the sealing of the fissure. The depth of penetration of fuschine dye as well as that of the tested material was measured with a grid. The results, compared to the depth of the fissures, are expressed in percentage of penetration. The results were as follows: penetration of fuschine dye: 0% for the 2 composites, 100% for Helioseal F; penetration of the materials: 96.90% for Helioseal F, 70.82 for Tetric and 86.10 for Tetric Flow (significant difference, Wilcoxon test = 0.0105). In this first in vitro study, Tetric Flow shows no microleakage and is more efficient when compared to Helioseal F and Tetric in obturating deep fissures of non carious bicuspids. The second experiment of the study evaluated the microleakage and the penetration depth of Tetric Flow when it is bonded by two different methods: Group 1: total etch (phosphoric acid) and Scotch-bond 1 (3M), and Group 2: self-etching primer with Prompt (Espe). There was no significant difference (p > 0.03) between classical bonding vs self-etching primer. The self-etching primer Prompt is very efficient vs phosphoric acid in obturating the fissures of non carious bicuspids with Tetric Flow. It is concluded that for prevention by sealing, using a flowable ceromer (Tetric Flow) with the self-etching (Prompt), is a really good technique.

  13. Oscillation of a Shallow Hydrothermal Fissure Inferred from Long-Period Seismic Events at Taal Volcano, the Philippines

    NASA Astrophysics Data System (ADS)

    Maeda, Y.; Kumagai, H.; Lacson, R.; Figueroa, M. S.; Yamashina, T.

    2012-12-01

    examine H2O gas (vapor) for simplicity. We calculated far-field waveforms generated by an oscillation of a crack containing vapor, and applied the Sompi method to estimate Q and nondimensional frequency. The estimated Q of a fundamental longitudinal mode oscillation was similar to the observation. We obtained a reasonable crack size (188 m) from a comparison of the observed peak frequency (0.8 Hz) with the calculated nondimensional frequency of the mode. In the swarm period of the LP events, other anomalies such as large volcano deformation and significant increase of gas emission from the main crater were not observed. This feature and the crack model result above suggest an active and localized vapor supply from magma at depth to the LP source. Such a localized supply may be realized by a transportation of vapor through a fissure. If we assume that the estimated crack volume (10^2 m^3) corresponds to vapor supplied to the LP source for each event, the total vapor mass supplied throughout the swarm period is ~10^7 kg. If we assume that this amount of vapor was originated by degassing from the magma and transported to the LP source through the fissure, we can estimate a magma volume of ~10^6 m^3. We thus suggest that the LP events at Taal were triggered by degassing and transportation of vapor from a deep magma to a shallow depth through a fissure.

  14. Potential for aquifer compaction, land subsidence, and earth fissures in Avra Valley, Pima and Pinal counties, Arizona

    USGS Publications Warehouse

    Anderson, S.R.

    1987-01-01

    Avra Valley is a large north-trending alluvial basin about 15 mi west of Tucson in Pima and Pinal Counties, Arizona. The climate of Avra Valley is semiarid, and the average annual precipitation ranges from 8 to 12 in. Two major ephemeral streams, the Santa Cruz River and Brawley Wash, drain the area. These streams and their tributaries provide a source of recharge to an extensive alluvial aquifer that underlies the valley floor. The aquifer consists of interbedded gravel, sand, silt, and clay and contains a vast quantity of groundwater. The physiography, fertile soil, and mild climate of Avra Valley make it an ideal environment for agriculture and urban development. Although the aquifer is replenished by natural recharge and underflow, rates of recharge and underflow have not kept pace with the rate of pumping. Pumping has exceeded recharge for several decades, resulting in a lowering of groundwater levels throughout most of the valley. In places, water level declines have resulted in small amounts of aquifer compaction and land subsidence. Earth fissures, some of which may be the result of localized differential subsidence, also have been observed in the valley. Geohydrologic characteristics of Avra Valley that may contribute to potential aquifer compaction, land subsidence, and earth fissures are described. The quantitative evaluation of potential land subsidence in this report is presented as an interim land- and water-use planning tool pending acquisition and study of additional data. Because of data limitations, the evaluation is made on the assumption that future rates of compaction and subsidence in Avra Valley will be similar to those in the Eloy-Picacho area. The evaluation also assumes that water level declines in the aquifer will continue. Several factors that may reduce groundwater withdrawals, and thus the potential for compaction and subsidence in Avra Valley, were not evaluated. These factors include the enactment of the 1980 Arizona Ground

  15. RECURRENT ECTOPIC CRANIOPHARYNGIOMA IN THE SYLVIAN FISSURE THIRTY YEARS AFTER RESECTION THROUGH A PTERIONAL APPROACH: A CASE REPORT AND REVIEW OF THE LITERATURE

    PubMed Central

    CLARK, SHANNON W.; KENNING, TYLER J.; EVANS, JAMES J.

    2015-01-01

    ABSTRACT Local recurrence of craniopharyngiomas after apparently complete resection occurs frequently. Ectopic recurrence remote from the original site has been reported in 18 adult patients. The interval between the original diagnosis and the time of recurrence varies widely in these reports (1–26 years). We report a case of an ectopic recurrence in the sylvian fissure of an adamantinomatous type craniopharyngioma 34 years after the initial presentation and 30 years after the last surgical resection. In addition to this being the latest reported ectopic recurrence, the location of this new lesion in the sylvian fissure is fairly rare, having been reported in only three other cases. We also reviewed the English literature for reports of ectopic recurrent craniopharyngiomas in order to conduct an analysis of surveillance and treatment strategies. PMID:25797995

  16. Comparative study of fluoride released and recharged from conventional pit and fissure sealants versus surface prereacted glass ionomer technology

    PubMed Central

    Salmerón-Valdés, Elias Nahum; Scougall-Vilchis, Rogelio J; Alanis-Tavira, Jorge; Morales-Luckie, Raúl Alberto

    2016-01-01

    Context: The fluoride release of sealants in vitro shows a marked decrease. Giomers are distinguishable from manufactured resin-based sealants and contain prereacted glass-ionomer particles (PRG). Aims: To compare the amounts of fluoride released from the main pit and fissure of a resin-based sealant with that from a Giomer and to assess the abilities of the sealant and the Giomer to recharge when exposed to regular use of fluoride rinse. Materials and Methods: The readings for the fluoride concentration were carried out for 60 days using a fluoride ion-specific electrode. After this period, the samples were recharged using a fluoride mouth rinse. The amount of fluoride released after this recharge was determined for 5 days. The data were analyzed using Student's t- and analysis of variance tests. Results: In general, all materials presented higher fluoride release in the first 24 h; G1 and G4 showed a higher fluoride release in this period. On the other hand, G3 and G1 presented the most constant fluoride release until the 8th day, wherein all the sealants considerably decreased in the amount of fluoride released. Conclusion: G1 and G3 released higher concentrations of fluoride, although no significant differences were found. Giomers recharged in the first 24 h after polymerization presented an improved and sustained fluoride release. PMID:26957792

  17. 640-Slice CT Measurement of Superior Orbital Fissure as Gateway for Light into the Brain: Statistical Evaluation of Area and Distance

    PubMed Central

    La Marra, Alice; Quarchioni, Simone; Ferrari, Fabiana; Gravina, Giovanni Luca; Barile, Antonio; Gregori, Lorenzo Maria; Di Cesare, Ernesto

    2016-01-01

    Objective Our aim was to provide normative data concerning superior orbital fissure area (SOFA), ocular skin and the substantia nigra (D-SS) and orbital fissure and the substantia nigra (D-SOF-S) distances by CT scan in adult Caucasian population Methods The area of the superior orbital fissure (SOF), the distance between the ocular skin and the substantia nigra and the distance between the superior orbital fissure and the substantia nigra using CT and 3D-CT images. Results Normative data stratified for age and gender were obtained. The data here reported show that some degree of variability in SOFA, D-SS and D-SOF-S measurements can be observed healthy Caucasian subjects. Gender stratified prediction intervals (mean +/- 2 Standard Deviations) for SOFA and D-SOF-S were 69.2 (+/-15.8) and 38.4 (+/-7.6) for male and 56.8 (+/-11.9) and 36.5 (+/-6.1) for female, respectively. Age and gender significantly impacted on D-SS values and normative data were constructed generating data stratified for these two variables. D-SS was 89.4 (+/-10.3) and 86.4 (+/-9.7) for male and female, respectively. Conclusions Here we provide adjunctive anatomical information on specific anatomical cerebral zones. Our data may have implications for surgeons actively committed to treat pathological conditions involving these cerebral areas. Additionally, the anatomical variability found with respect to SOF and the potential different exposure of the substanzia nigra to the bright light could play a role in Parkinson’s disease as already speculated in literature. PMID:27661082

  18. Analysis of the dental morphology of Plio-Pleistocene hominids. II. Mandibular molars--study of cusp areas, fissure pattern and cross sectional shape of the crown.

    PubMed Central

    Wood, B A; Abbott, S A; Graham, S H

    1983-01-01

    Accurate measurements of the absolute and relative size of individual cusps, the arrangement of the primary fissure system and the shape of coronal cross sections of the tooth crown have been used to investigate the pattern of variation in Plio-Pleistocene hominid mandibular molar teeth. Teeth were either grouped into one of six taxonomic categories or considered as individual cases. Univariate analysis of relative cusp areas shows that the two taxonomic categories of 'robust' hominids from East and Southern Africa have relatively small mesial cusps, but a relatively large entoconid and hypoconulid and Principal Component plots of the data show that the 'robust' categories can be distinguished on the basis of relative cusp size. Other evidence suggests that these differences are not likely to be the result of allometric phenomena. Fissure pattern was analysed using the X/Y coordinates of defined reference points. Patterns were compared by Procrustes analysis and the relationships between teeth contained in the resulting similarity matrix were portrayed using Principal Coordinates plots and a nearest neighbours table. The positions of the posterior fovea and the mesial longitudinal fissure were important for distinguishing taxonomic categories. The shape of the coronal profiles proved difficult to quantify, but there were consistent and distinct differences between the South African 'robust' sample and teeth included within the East African Homo category. When these results are combined with those of a previous study of overall crown size and the distribution of extra cusps, they allow the affinities of isolated teeth or contentious specimens to be assessed. For example, our results show that KNM-ER 1506 and 1802 are more similar to the East African Homo group than any other category, and they indicate that though SK 1587 and 1588 are small teeth, they nonetheless are closest to the South African 'robust' category in terms of relative cusp size, fissure pattern and

  19. Influence of extended light exposure curing times on the degree of conversion of resin-based pit and fissure sealant materials

    PubMed Central

    Fatima, Nazish

    2014-01-01

    Purpose The aim of present study was to evaluate extended curing times on the degree of conversion (DC) of filled and unfilled resin-based materials used as pit and fissure sealants. Materials and methods The materials examined were a flowable composite (Filtek™ Z350 XT Flowable) and a pit and fissure sealant (Clinpro™ Sealant). Thirty disks of each material were prepared. The 30 made of the flowable composite were divided into three groups (n = 10 each) according to the three different curing times studied: 20 s (group 1), 40 s (group 2), and 60 s (group 3). Similarly, the 30 disks made of the pit and fissure sealant were divided into three groups (n = 10 each) according to the three different curing times: 20 s (group 4), 40 s (group 5), and 60 s (group 6). After polymerization, the disks were removed from the mold and stored in dry, lightproof containers in an incubator at 37 °C for 24 h. The DC was obtained using an Avatar 320 FTIR spectrometer. Then the data were analyzed using the Kruskal–Wallis test and the Fisher’s least significant difference post hoc test for multiple comparisons (alpha = 0.05). Results DC values for the flowable composite (Filtek™ Z350 XT) were higher (p = 0.002) than those for the pit and fissure sealant (Clinpro™ Sealant). Group 2 and group 5 showed significantly higher DC values than group 1 and group 4, respectively. There was no difference between groups 2 and 3 or between groups 5 and 6 (p = 2.93). Conclusion An extended curing time improves the DC to some extent for both materials. PMID:25382947

  20. Effects of Aloe vera cream on chronic anal fissure pain, wound healing and hemorrhaging upon defection: a prospective double blind clinical trial.

    PubMed

    Rahmani, N; Khademloo, M; Vosoughi, K; Assadpour, S

    2014-01-01

    Aloe vera is a medicinal plant that promotes wound healing in burn injuries. A prospective clinical trial was conducted to evaluate the effects of a topical cream containing 0.5% Aloe vera juice powder in the treatment of chronic anal fissures. The aloe cream was applied by the patients to the wound site 3 times per day for 6 weeks following the instructions of a physician. Pain was assessed with a visual analog scale before treatment and at the end of each week of treatment. Wound healing and the amount and severity of bleeding were examined and evaluated before and at the end of each week of treatment. There were statistically significant differences in chronic anal fissure pain, hemorrhaging upon defection and wound healing before and at the end of the first week of treatment also in comparison with control group (p < 0.0001). In this study, a topical cream containing aloe vera juice was an effective treatment for chronic anal fissures. This is a promising result indicating that further comparative studies are justified.

  1. Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas

    PubMed Central

    Borgonie, Gaëtan; Linage-Alvarez, Borja; Ojo, Abidemi; Shivambu, Steven; Kuloyo, Olukayode; Cason, Errol D.; Maphanga, Sihle; Vermeulen, Jan-G; Litthauer, Derek; Ralston, Colin D.; Onstott, Tullis C.; Sherwood-Lollar, Barbara; Van Heerden, Esta

    2015-01-01

    Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing. PMID:26441844

  2. Evolution of dike opening during the March 2011 Kamoamoa fissure eruption, Kīlauea Volcano, Hawai`i

    USGS Publications Warehouse

    Lundgren, Paul; Poland, Michael; Miklius, Asta; Orr, Tim R.; Yun, Sang-Ho; Fielding, Eric; Liu, Zhen; Tanaka, Akiko; Szeliga, Walter; Hensley, Scott; Owen, Susan

    2013-01-01

    The 5–9 March 2011 Kamoamoa fissure eruption along the east rift zone of Kīlauea Volcano, Hawai`i, followed months of pronounced inflation at Kīlauea summit. We examine dike opening during and after the eruption using a comprehensive interferometric synthetic aperture radar (InSAR) data set in combination with continuous GPS data. We solve for distributed dike displacements using a whole Kīlauea model with dilating rift zones and possibly a deep décollement. Modeled surface dike opening increased from nearly 1.5 m to over 2.8 m from the first day to the end of the eruption, in agreement with field observations of surface fracturing. Surface dike opening ceased following the eruption, but subsurface opening in the dike continued into May 2011. Dike volumes increased from 15, to 16, to 21 million cubic meters (MCM) after the first day, eruption end, and 2 months following, respectively. Dike shape is distinctive, with a main limb plunging from the surface to 2–3 km depth in the up-rift direction toward Kīlauea's summit, and a lesser projection extending in the down-rift direction toward Pu`u `Ō`ō at 2 km depth. Volume losses beneath Kīlauea summit (1.7 MCM) and Pu`u `Ō`ō (5.6 MCM) crater, relative to dike plus erupted volume (18.3 MCM), yield a dike to source volume ratio of 2.5 that is in the range expected for compressible magma without requiring additional sources. Inflation of Kīlauea's summit in the months before the March 2011 eruption suggests that the Kamoamoa eruption resulted from overpressure of the volcano's magmatic system.

  3. Ground based measurements of the gas emission from the Holuhraun volcanic fissure eruption on Iceland 2014/2015

    NASA Astrophysics Data System (ADS)

    Galle, Bo; Arellano, Santiago; Conde, Vladimir; Pfeffer, Melissa; Barsotti, Sara; Stefansdottir, Gerður; Bergsson, Baldur; Bergsson, Bergur; Ingvarsson, Thorgils; Weber, Konradin

    2015-04-01

    The since 31 August 2014 ongoing volcanic eruption at Holuhraun on Iceland is by far the strongest source of sulfur dioxide in Europe over the last 230 years with sustained emission rates exceeding 100 000 ton/day. This gas emission severely affects local population and has become a concern also for air traffic. The eruption has in December continued at constant pace for 3.5 months. Three scenarios are envisaged for the future; (1) the eruption stops, (2) the fissure extends under the Vattnajökul glacier and (3) Bardarbunga volcano erupts. The two later scenarios will cause increased gas emission, severe ash emissions and extended flooding. Under the scope of the EU-project FUTUREVOLC, a project with 3.5 years duration, aiming at making Iceland a supersite for volcanological research as a European contribution to GEO, we are developing a version of the Scanning DOAS instrument that is adapted to high latitudes with low UV radiation and severe meteorological conditions. Since the first day of the eruption several of these novel instruments has been monitoring the SO2 emission from the eruption. Data from our instruments are still after 3.5 months the only sustained ground-based monitoring of this gas emission. A lot of work is however needed to sustain this operation at a very remote site and under severe field conditions. At the same time the very high concentrations in the gas plume, in combination with bad meteorological conditions require the development of novel methods to derive reliable flux estimates. In this presentation we will discuss the instrumental issues and present the latest version of the emission estimates made from our measurements.

  4. Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas.

    PubMed

    Borgonie, Gaëtan; Linage-Alvarez, Borja; Ojo, Abidemi; Shivambu, Steven; Kuloyo, Olukayode; Cason, Errol D; Maphanga, Sihle; Vermeulen, Jan-G; Litthauer, Derek; Ralston, Colin D; Onstott, Tullis C; Sherwood-Lollar, Barbara; Van Heerden, Esta

    2015-01-01

    Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing. PMID:26441844

  5. Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas.

    PubMed

    Borgonie, Gaëtan; Linage-Alvarez, Borja; Ojo, Abidemi; Shivambu, Steven; Kuloyo, Olukayode; Cason, Errol D; Maphanga, Sihle; Vermeulen, Jan-G; Litthauer, Derek; Ralston, Colin D; Onstott, Tullis C; Sherwood-Lollar, Barbara; Van Heerden, Esta

    2015-01-01

    Stalactites (CaCO3 and salt) from water seeps are frequently encountered in ceilings of mine tunnels whenever they intersect water-bearing faults or fractures. To determine whether stalactites could be mineralized traps for indigenous fracture water microorganisms, we analyzed stalactites collected from three different mines ranging in depth from 1.3 to 3.1 km. During sampling in Beatrix gold mine (1.4 km beneath the surface), central South Africa, CaCO3 stalactites growing on the mine tunnel ceiling were collected and observed, in two cases, to contain a living obligate brackish water/marine nematode species, Monhystrella parvella. After sterilization of the outer surface, mineral layers were physically removed from the outside to the interior, and DNA extracted. Based upon 16S and 18S rRNA gene sequencing, Archaea, Bacteria, and Eukarya in different combinations were detected for each layer. Using CT scan and electron microscopy the inner structure of CaCO3 and salt stalactites were analyzed. CaCO3 stalactites show a complex pattern of lamellae carrying bacterially precipitated mineral structures. Nematoda were clearly identified between these layers confirming that bacteria and nematodes live inside the stalactites and not only in the central straw. Salt stalactites exhibit a more uniform internal structure. Surprisingly, several Bacteria showing highest sequence identities to marine species were identified. This, together with the observation that the nematode M. parvella recovered from Beatrix gold mine stalactite can only survive in a salty environment makes the origin of the deep subsurface colonization enigmatic. The possibility of a Permian origin of fracture fluids is discussed. Our results indicate stalactites are suitable for biodiversity recovery and act as natural traps for microorganisms in the fissure water long after the water that formed the stalactite stopped flowing.

  6. Caries-Preventive Effect of High-Viscosity Glass Ionomer and Resin-Based Fissure Sealants on Permanent Teeth: A Systematic Review of Clinical Trials

    PubMed Central

    Mickenautsch, Steffen; Yengopal, Veerasamy

    2016-01-01

    Background Glass-ionomers are traditionally regarded to be inferior to resin as fissure sealants in protecting teeth from dental caries, due to their comparatively lower retention rate. Unlike low-viscosity glass-ionomers, high-viscosity glass-ionomer cements (HVGIC) are placed as sealants by pressing the material into pits and fissures with a petroleum-jelly-coated index finger. Hence, HVGIC sealants are assumed to penetrate pits and fissures deeper, resulting in a higher material retention rate, which may increase its caries-preventive effect. Methods The aim of this review was to answer the question as to whether, in patients with fully erupted permanent molar teeth, HVGIC based fissure sealants are less effective to protect against dental carious lesions in occlusal pits and fissures than resin-based fissure sealants? A systematic literature search in eight databases was conducted. Heterogeneity of accepted trials and imprecision of the established evidence were assessed. Extracted sufficiently homogenous datasets were pooled by use of a random-effects meta-analysis. Internal trial validity was evaluated. The protocol of this systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO / Nr.: CRD42015016007). Results Seven clinical trials were provisionally included for further review. Of these, one was excluded. Seven trial reports reporting on six trials were accepted. From these, 11 datasets were extracted and pooled in four meta-analyses. The results suggest no statistically significant differences after up to 48 months and borderline significant differences in favour of HVGIC sealants after 60 months (RR 0.29; 95% CI: 0.09–0.95; p = 0.04 / RD -0.07; 95% CI: -0.14, -0.01). The point estimates and upper confidence levels after 24, 36, 48 and 60 months of RR 1.36; RR 0.90; RR 0.62; RR 0.29 and 2.78; 1.67; 1.21; 0.95, respectively, further suggest a chronological trend in favour of HVGIC above resin

  7. Non-destructive measurement of demineralization and remineralization in the occlusal pits and fissures of extracted 3rd molars with PS-OCT

    NASA Astrophysics Data System (ADS)

    Lee, Chulsung; Hsu, Dennis J.; Le, Michael H.; Darling, Cynthia L.; Fried, Daniel

    2009-02-01

    Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image the remineralization of early artificial caries lesion on smooth enamel surfaces of human and bovine teeth. However, most new dental decay is found in the pits and fissures of the occlusal surfaces of posterior dentition and it is in these high risk areas where the performance of new caries imaging devices need to be investigated. The purpose of this study was to demonstrate that PS-OCT can be used to measure the subsequent remineralization of artificial lesions produced in the pits and fissures of extracted 3rd molars. A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of occlusal surfaces exposed to a demineralizing solution at pH-4.5 followed by a fluoride containing remineralizing solution at pH-7.0 containing 2-ppm fluoride. The integrated reflectivity was calculated to a depth of 200-µm in the entire lesion area using an automated image processing algorithm. Although a well-defined surface zone was clearly resolved in only a few of the samples that underwent remineralization, the PS-OCT measurements indicated a significant (p<0.05) reduction in the integrated reflectivity between the severity of the lesions that were exposed to the remineralization solution and those that were not. The lesion depth and mineral loss were also measured with polarized light microscopy and transverse microradiography after sectioning the teeth. These results show that PS-OCT can be used to non-destructively monitor the remineralization potential of anti-caries agents in the important pits and fissures of the occlusal surface.

  8. Monitoring of the volcanic rock compositions during the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Volynets, Anna O.; Edwards, Benjamin R.; Melnikov, Dmitry; Yakushev, Anton; Griboedova, Irina

    2015-12-01

    Here we present the results from monitoring of the composition of rocks produced during the 2012-2013 fissure eruption at Tolbachik volcano (FTE). Major and trace element concentrations in 75 samples are reported. Products of this eruption are represented by high alumina basaltic trachyandesites with higher alkalis and titanium contents than in all previously studied rocks of the Tolbachik monogenetic volcanic field. Rocks erupted during the first three days (27-30 November) from the northern (also called Menyailov) group of vents are the most silica- and alkali-rich (SiO2 concentrations up to 55.35 wt.% and K2O up to 2.67 wt.%). From December onwards, when the eruptive activity switched from the Menyailov vents to the southern (Naboko) group of vents, silica content dropped by 2 wt.%, concentrations of MgO, FeO, TiO2 and Mg# increased, and K2O and Na2O concentrations and K2O/MgO ratio decreased. For the rest of the eruption the compositions of rocks remained constant and homogeneous; no systematic compositional differences between lava, bombs and scoria samples are evident. Trace element distributions in the rocks of the Menyailov and Naboko vent lavas are relatively uniform; Menyailov lavas have slightly higher Th, Nb, Hf, Y, and HREE concentrations than the Naboko vent lavas at more or less constant element ratios. We explain the initial change in geochemistry by tapping of a slightly cooler and fractionated (~ 3% Mt and 8% Cpx) upper part of the magma storage zone before the main storage area began to feed the eruption. Thermodynamic constraints show that apparent liquidus temperatures varied from 1142 °C to 1151 °C, and thermodynamic modeling shows that variations in compositions are consistent with a high degree of low pressure (100-300 MPa), nominally anhydrous fractionation of a parent melt compositionally similar to the 1975 Northern Breakthrough high-Mg basalt. Geochemistry, petrological observations and modeling are in agreement with the newly erupted

  9. Transient Source Processes Prior to the March 2011 Kamoamoa Fissure Eruption, Kīlauea Volcano, Hawaíi

    NASA Astrophysics Data System (ADS)

    Lundgren, P.; Poland, M. P.; Miklius, A.; Anderson, K. R.

    2014-12-01

    Interferometric synthetic aperture radar (InSAR) and continuous GPS observations at the summit of Kīlauea Volcano, Hawaíi, show spatially and temporally transient surface displacements in the months and weeks before the 5-9 March 2011 Kamoamoa fissure eruption. Interferograms computed from the Italian Space Agency's COSMO-SkyMed satellites and the German Aerospace Center's TerraSAR-X satellite show a distinctive triangular pattern of surface deformation that extends to the SE of Kīlauea Caldera starting approximately one month prior to the Kamoamoa eruption. GPS and electronic tilt meter time series for sites in the vicinity of this deformation show that this inflation transient is superimposed on the longer (~4-6 month) summit inflation. We examine and model the spatiotemporal evolution of the summit deformation. InSAR data from ascending and descending tracks are used to constrain models of the transient. To achieve low-levels of atmospheric phase noise required interferograms spanning four months prior to the eruption, thus involving multiple sources within the summit region (see figure). To solve for model parameters we use a Markov Chain Monte Carlo optimization approach. First, we model the co-eruption summit deflation to isolate the intra-caldera sources, consisting of a steeply dipping tensile dislocation (D) beneath the western edge of the caldera and a sub-horizontal, NE trending spheroidal pressure source (Y) in the center of the caldera at 1.5 km depth. We use these sources as starting models for the pre-eruption transient, which requires the addition of a sill (S) to explain the deformation that extends to the SE of the caldera. In a third step we add a simplified model for Kīlauea's rifts and basal detachment system to explain the coupled summit and south flank motion. Modeled at over 3 km beneath the surface, the transient sill source inflates over the month before the eruption and deflates during the four-day eruption. The sill runs parallel to

  10. Tracking the seismicity preceding and during the March 2010 Fimmvörduháls fissure eruption and April 2010 summit eruption of Eyjafjallajökull, Iceland

    NASA Astrophysics Data System (ADS)

    Tarasewicz, J.; Brandsdottir, B.; Hensch, M.; White, R. S.

    2010-12-01

    Using Coalescence Microseismic Mapping (CMM) we have located over 9,000 earthquakes in the period starting two weeks prior to the Fimmvörduháls fissure eruption at the northeastern margin of the Eyjafjallajökull stratovolcano, South Iceland. CMM is an automatic earthquake detection and location program developed at Cambridge University which performs a search in time and space for a best-fit earthquake location. This is done by migrating both P and S wave energy from each seismometer location back into the subsurface and finding an optimum event location where the back-projected energy coalesces within a specified search volume by fitting it to a grid for which P- and S-wave travel times have been calculated from each point in the grid to every seismometer. Following a prolonged period of escalating seismicity we deployed six temporary, three-component, broadband seismometers around the Eyjafjallajökull volcano on 5th March 2010. Data from these seismometers were augmented by data from the eight closest seismometers of the permanent network operated by the Icelandic Meteorological Office (IMO). During March 2010, sustained seismic activity was concentrated primarily between 3-6 km depth under the northeastern flank of the Eyjafjallajökull volcano. To first order, the seismicity migrated eastwards away from the Eyjafjallajökull caldera and towards the first eruption site at Fimmvörduháls during the two weeks prior to eruption. We attribute this to melt movement within the crust. However, clusters in three (or more) discrete locations on the northeastern flank are observed to have been active simultaneously, or with activity alternating between locations, suggesting that magma movement was more complex than a single dyke propagating towards the Fimmvörduháls eruption site. Seismic activity decreased markedly in the two days prior to the onset of the fissure eruption on March 20th. The fissure eruption continued until 12th April and was a pre-cursor to the

  11. Superior Orbital Fissure Syndrome and Ophthalmoplegia Caused by Varicella Zoster Virus with No Skin Eruption in a Patient Treated with Tumor Necrosis Alpha Inhibitor.

    PubMed

    Jensen, Helene; Thomsen, Sidsel Thorup; Hansen, Stine Scott; Munksgaard, Signe Bruun; Lindelof, Mette

    2015-01-01

    Varicella zoster virus lies dormant in the dorsal root ganglia after symptomatic chicken pox infection, usually in childhood. If the virus reactivates in the trigeminal ganglia, it can cause varicella zoster ophthalmicus, which can have severe ocular complications. We report a case of a 73-year-old woman in severe immunosuppression due to treatment with mycophenolate mofetil, glucocorticosteroids and a tumor necrosis factor alpha inhibitor. The reactivation caused superior orbital fissure syndrome, which has only rarely been described in relation to varicella zoster virus reactivation. In our case, the syndrome was seen along with severe encephalitis.

  12. Glass ionomer ART sealant and fluoride-releasing resin sealant in fissure caries prevention – results from a randomized clinical trial

    PubMed Central

    2014-01-01

    Background The relative performance of ART sealant and fluoride-releasing resin sealant in preventing fissure caries in permanent molars was compared in a randomized clinical trial conducted in southern China (ClinicalTrials.gov NCT01829334). Methods After obtaining ethical approval, healthy schoolchildren who had permanent first molars with occlusal fissures which were sound but deep or presented with only incipient caries were recruited for the study. Included molars were randomly allocated into one of four parallel study groups in units of left/right teeth per mouth. Two of the four groups adopted the methods of ART or fluoride-releasing resin sealant placement while the other two groups adopted the topical fluoride application methods. Fissure status of the molars in each group was evaluated every 6 months. Development of dentine caries and sealant retention over 24 months in the molars in the two sealant-using groups was compared in this report. Outcome on cost-effectiveness of all four groups over 36 months will be reported elsewhere. Results At baseline, a total of 280 children (383 molars) with mean age 7.8 years were involved for the two sealant groups. After 24 months, 261 children (357 molars) were followed. Proportions of molars with dentine caries were 7.3% and 3.9% in the ART sealant and fluoride-releasing resin sealant groups, respectively (chi-square test, p = 0.171). Life-table survival analysis showed that sealant retention (full and partial) rate over 24 months for the resin sealant (73%) was significantly higher than that (50%) for the ART sealant (p < 0.001). Molar survival (no development of dentine caries) rates in the ART sealant (93%) and fluoride-releasing resin sealant (96%) groups were not significantly different (p = 0.169). Multilevel logistic regression (GEE modeling) accounting for the effects of data clustering and confounding factors confirmed this finding. Conclusions Though the retention of fluoride

  13. Tectono-volcanic control of fissure type vents for the 28 Ma Panalillo ignimbrite in the Villa de Reyes Graben, San Luis Potosí, México.

    NASA Astrophysics Data System (ADS)

    Tristán-González, Margarito; Labarthe-Hernández, Guillermo; Aguirre-Díaz, Gerardo J.; Aguillón-Robles, Alfredo

    2008-10-01

    The volcano-tectonic events at the Villa de Reyes Graben (VRG), in the southern Sierra Madre Occidental, Mexico, include 1) a regional NNE fault system developed before 32 Ma, 2) this pre-32 Ma faulting controlled the emplacement of 31.5 Ma dacitic domes, 3) NE faulting at 28 Ma that displaced the 31.5 Ma dacitic domes and formed the VRG, as well as the oblique grabens of Bledos and Enramadas oriented NW, 4) emplacement of Panalillo ignimbrite at 28 Ma filling the VRG and erupting from fissures related to the oblique grabens, and eruption of Placa basalt apparently also from fault-controlled vents.

  14. Remote sensing and petrological observations on the 2012-2013 fissure eruption at Tolbachik volcano, Kamchatka: Implications for reconstruction of the eruption chronology

    NASA Astrophysics Data System (ADS)

    Melnikov, Dmitry; Volynets, Anna O.

    2015-12-01

    We present a reconstruction of the chronological sequence of events that took place during the first days of the 2012-2013 Tolbachik fissure eruption using petrological data and remote sensing methods. We were forced to use this approach because bad weather conditions did not allow direct observations during the first two days of the eruption. We interpreted infrared images from the scanning radiometer VIIRS Suomi NPP and correlated the output with the results of the geochemical study, including comparison of the ash, deposited at the period from 27 to 29 November, with the samples of lava and bombs erupted from the Menyailov and Naboko vents. We argue that the compositional change observed in the eruption products (the decrease of SiO2 concentration and K2O/MgO ratio, increase of MgO concentration and Mg#) started approximately 24 h after the eruption began. At this time the center of activity moved to the southern part of the fissure, where the Naboko group of vents was formed; therefore, this timeframe also characterizes the timing of the Naboko vent opening. The Naboko group of vents remained active until the end of eruption in September 2013.

  15. Can extended photoactivation time of resin-based fissure sealer materials improve ultimate tensile strength and decrease water sorption/solubility?

    PubMed Central

    Borges, Boniek Castillo Dutra; Souza-Júnior, Eduardo José; Catelan, Anderson; Paulillo, Luís Alexandre Maffei Sartini; Aguiar, Flávio Henrique Baggio

    2012-01-01

    Objective: This study aimed to evaluate the impact of extended photoactivation time on ultimate tensile strength (UTS), water sorption (WS) and solubility (WSB) of resin-based materials used as fissure-sealants. Methods: A fissure-sealant (Fluroshield) and a flowable composite (Permaflo) polymerized for 20 and 60 seconds were tested. For UTS, 20 hourglass shaped samples were prepared representing two materials and two photoactivation time (n=5). After 24-h dry-storage, samples were tested in tension using a universal testing machine at a cross-head speed of 0.5 mm/min (UTS was calculated in MPa). For WS and WSB, 20 disks with 5 mm diameter and 1 mm height (n=5) were prepared and volumes were calculated (mm3). They were transferred to desiccators until a constant mass was obtained (m1) and were subsequently immersed in distilled water until no alteration in mass was detected (m2). Samples were reconditioned to constant mass in desiccators (m3). WS and WSB were determined using the equations m2-m3/V and m1-m3/V, respectively. Data were subjected to two-way ANOVA and Tukey’s HSD test (P<.05). Results: There was no significant difference between materials or photoactivation times for the UTS and WS. Permaflo presented lower but negative WSB compared to Fluroshield. Conclusions: Extended photoactivation time did not improve the physical properties tested. Fluroshield presented physical properties that were similar to or better than Permaflo. PMID:23077420

  16. 3D model of fault and fissures structure of the Kovdor Baddeleyite-Apatite-Magnetite Deposit (NE of the Fennoscandian Shield)

    NASA Astrophysics Data System (ADS)

    Zhirov, Dmitry; Klimov, Sergey

    2015-04-01

    The Kovdor baddeleyite-apatite-magnetite deposit (KBAMD) is represented by a large vertical ore body and is located in the southwestern part of the Kovdor ultramafic-alkaline central-type intrusion. The intrusion represents a concentrically zoned complex of rocks with an oval shape in plan, and straight zoning, which complies with the injection and displacement of each of further magma phases from the center towards the periphery. The operation of the deposit in open pits started in 1962, and nowadays, it has produced over 500,000,000 tons of ore. This is one of the largest open pits in the Kola region, which is ca. 2 km long, 1.8 km wide, and over 400 m deep. Regular structural studies has been carried out since late 1970. A unique massif of spatial data has been accumulated so far to include over 25,000 measurements of fissures and faults from the surface, ca. 20,000 measurements of fissures in the oriented drill core (over 18 km) etc. Using this data base the 3D model of fault and fissures structure was designed. The analysis of one has resulted in the identification of a series of laws and features, which are necessary to be taken into account when designing a deep open pit and mining is carried out. These are mainly aspects concerning the origin, kinematics, mechanics and ratio of spatial extension of various fault systems, variation of their parameters at deep horizons, features of a modern stress field in the country rocks, etc. The 3D model has allowed to divide the whole fracture / fissure systems of the massif rocks into 2 large groups: prototectonic system of joints, including cracks of 'liquid magmatic (carbonatite stage) contraction genesis', and newly formed faults due to the superimposed tectonic stages. With regard to the deposit scale, these are characterized as intraformational and transformational, respectively. Each group shows a set (an assemblage) of fault systems with unique features and signs, as well as regular interconnections. The

  17. 18O/16O studies of fossil fissure fumaroles from the Valley of Ten Thousand Smokes, Alaska

    NASA Astrophysics Data System (ADS)

    Warner Holt, Elizabeth; Taylor, Hugh

    2001-03-01

    At three sample sites where there are good exposures of the upper 15 m of the 1912 ash-flow sheet in the Valley of Ten Thousand Smokes (VTTS), Alaska, 18O/16O studies indicate that fumarolic activity produced a very wide range of δ18O values (-0.1 to +12.6; n=32) in the groundmass adjacent to fossil fissure fumaroles. This contrasts sharply with the uniformity of δ18O in the groundmass away from fumarolic conduits (δ18O=+5.9 to +7.1; n=7) and in all of the feldspar phenocrysts (δ18O=+6.11 to +7.51 for 11 samples from this study and Hildreth 1987), independent of whether these were collected from fossil fumaroles or from unaltered tuff. Only one sample contained feldspars that were even slightly 18O-enriched relative to the others (cloudy plagioclase δ18O=+8.45), and this sample also contained the most 18O-enriched groundmass of any of those analyzed (δ18O=+12.6). This preservation of primary magmatic δ18O values in the VTTS feldspar phenocrysts is clearly a consequence of the extremely short time span (i.e., 1912 to 1923) of vigorous, high-temperature, fumarolic activity in the 1912 ash-flow sheet. These 18O/16O systematics are strikingly similar to those discovered in the 2.8-Ma intracaldera Chegem Tuff (Gazis et al. 1996) and in the fossil fumaroles in the outflow sheet of the 0.76 Ma Bishop Tuff (Holt and Taylor 1998), thus confirming that a similar type of fumarolic meteoric-hydrothermal activity occurred above the zone of intense welding in all three of these ash-flow tuffs. This is particularly important, because it provides a direct linkage between the older tuffs and the actual observations at the VTTS of steam chemistry, water/rock interaction, circulation geometry, flow velocities, and fumarolic temperatures (up to 645°C). The 18O/16O effects in the VTTS can all be explained in terms of a two-stage history: (a) an early, 10- to 15-year-long, high-temperature (>450°C), fumarolic 18O-depletion event (groundmass δ18O=-0.1 to +4.8); and (b) a

  18. 18O/16O studies of fossil fissure fumaroles from the Valley of Ten Thousand Smokes, Alaska

    NASA Astrophysics Data System (ADS)

    Holt, Elizabeth Warner; Taylor, Hugh P.

    2001-06-01

    At three sample sites where there are good exposures of the upper 15 m of the 1912 ash-flow sheet in the Valley of Ten Thousand Smokes (VTTS), Alaska, 18O/16O studies indicate that fumarolic activity produced a very wide range of δ18O values (-0.1 to +12.6; n=32) in the groundmass adjacent to fossil fissure fumaroles. This contrasts sharply with the uniformity of δ18O in the groundmass away from fumarolic conduits (δ18O=+5.9 to +7.1; n=7) and in all of the feldspar phenocrysts (δ18O=+6.11 to +7.5 1 for 11 samples from this study and Hildreth 1987), independent of whether these were collected from fossil fumaroles or from unaltered tuff. Only one sample contained feldspars that were even slightly 18O-enriched relative to the others (cloudy plagioclase δ18O=+8.45). and this sample also contained the most 180-enriched groundmass of any of those analyzed (δ18O=+12.6). This preservation of primary magmatic δ18O values in the VTTS feldspar phenocrysts is clearly a consequence of the extremely short time span (i.e., 1912 to ≈1923) of vigorous, high-temperature, fumarolic activity in the 1912 ash-flow sheet. These 18O/l6O systematica are strikingly similar to those discovered in the 2.8-Ma intracaldera Chegem Tuff (Gazis et al. 1996) and in the fossil fumaroles in the outflow sheet of the 0.76 Ma Bishop Tuff (Holt and Taylor 1998), thus confirming that a similar type of fumarolic meteoric-hydro-thermal activity occurred above the zone of intense welding in all three of these ash-flow tuffs. This is particularly important, because it provides a direct linkage between the older tuffs and the actual observations at the VTTS of steam chemistry, water/rock interaction, circulation geometry, flow velocities, and fumarolic temperatures (up to 645°C). The 18O/l6O effects in the VTTS can all be explained in terms of a two-stage history: (a) an early, 10- to 15-year-long, high-temperature (τ;450°C), fumarolic 18O-depletion event (groundmass δ18O=-0.1 to +4.8); and (b) a

  19. Near-Vent, Fissure-Fed Lava Channel Network Morphologies in the Kīlauea December 1974 Flow: Implications for Differentiating Lava Construction From Fluvial Erosion on Planets

    NASA Astrophysics Data System (ADS)

    Bleacher, J. E.

    2015-12-01

    Streamlined islands are often assumed to be the product of erosion by water and are cited as evidence of aqueous flows on Mars. However, lava can build streamlined islands in a manner that is more easily explained by flow thickening followed by partial drainage of preferred lava pathways. Kīlauea's December 1974 (D1974) flow was emplaced as a broad sheet-like flow from a series of en echelon fissures across an older hummocky pāhoehoe tumulus field. The lavas surrounded the tumuli and coalesced to fill a topographic low near the basal scarp of the Koae Fault System. As these obstacles were inundated by the D1974 flow, the lava preferentially cooled around the tumuli to form a higher viscosity zone beneath a smooth crust. Stagnation of these thinner, cooler, and more viscous zones focused the flow into a series of preferred lava pathways located between the stagnant islands. Changes in the local discharge rate disrupted the crust of the flow above the lower viscosity pathways. Older tumuli adjacent to the D1974 flow display the same relief as the flow's islands and uncovered portions of this older flow are exposed at the tops of many islands, supporting an interpretation that islands were anchored by high-standing pre-flow tumuli. As the local lava supply waned, partial drainage of the preferred pathways occurred between the higher-standing surfaces anchored to the older tumuli. The resulting morphology consists of a relatively smooth flow field with thin margins that is dissected by depressed pathways or channels. This morphology resembles an erosional surface incised into a smooth plain, but actually represents an initial constructional process followed by partial drainage within a viscous lava flow. Many other Hawaiian rift zone, fissure-fed flow fields display comparable morphologies in the near vent facies, including islands, terraces, thin flow margins and a lack of well defined topographic levees along channels. Thus, branching channel networks and

  20. Long-distance magma transport from arc volcanoes inferred from the submarine eruptive fissures offshore Izu-Oshima volcano, Izu-Bonin arc

    NASA Astrophysics Data System (ADS)

    Ishizuka, Osamu; Geshi, Nobuo; Kawanabe, Yoshihisa; Ogitsu, Itaru; Taylor, Rex N.; Tuzino, Taqumi; Sakamoto, Izumi; Arai, Kohsaku; Nakano, Shun

    2014-09-01

    Long-distance lateral magma transport away from volcanic centers in island arcs is emerging as a common phenomenon where the regional stress regime is favorable. It should also be recognized as an important factor in the construction and growth of island arcs, and a potential trigger for devastating eruptions. In this contribution, we report on recent investigations into the magma dynamics of Izu-Oshima volcano, an active basaltic volcano with an extensive fissure system. Izu-Oshima is flanked by numerous, subparallel NW-SE trending submarine ridges extending up to 22 km to the NW and the SE from the central vent. During a recent submersible survey we have identified that these ridges are fissures which erupted basaltic spatter and lava flows. Furthermore, lavas are petrographically similar along each ridge, while there are noticeable differences between ridges. The subparallel ridges are observed to transect a series of seamounts - the Izu-Tobu monogenetic volcanoes - which are dispersed across this area of the rear-arc. However, there are consistent petrographic and chemical differences between these seamounts and the ridges, indicating that they have different magma sources, yet, they are essentially bounding each other in dive tracks. The most appropriate scenario for their development is one where the Izu-Tobu Volcanoes are fed by an "in-situ" underlying source, while the NW-SE ridges are fed by lateral magma transport from Izu-Oshima. Magma erupted from each ridge is of a consistent geochemistry along its length, but has experienced crystal fractionation and some plagioclase accumulation. Compositions of the ridges are also very similar to lavas from the subaerial cones that can be traced down the flanks of Izu-Oshima. This implies that pairs of subaerial cones and submarine ridges represent the locus of magma transport events away from the storage system beneath Izu-Oshima. Hence, magma from this crustal reservoir moved upward to feed the on-edifice cones

  1. Observations of a substantial cloud-aerosol indirect effect during the 2014-2015 Bárðarbunga-Veiðivötn fissure eruption in Iceland

    NASA Astrophysics Data System (ADS)

    McCoy, Daniel T.; Hartmann, Dennis L.

    2015-12-01

    The Bárðarbunga-Veiðivötn fissure eruption lasted from 31 August 2014 to 28 February 2015, during which its sulfur emissions dwarfed anthropogenic emissions from Europe. This natural experiment offers an excellent opportunity to investigate the aerosol indirect effect and the effect of effusive volcanic eruptions on climate. During the eruption cloud droplet effective radius (re) over the region surrounding Iceland was at the lowest value in the 14 year Moderate Imaging Spectroradiometer data record during September and October 2014. The change in reflected solar radiation due to increased cloud reflectivity during September and October is estimated to exceed 2 W m-2 over the region surrounding Iceland, with increases of 1 W m-2 extending as far south as the Açores. The strength of the aerosol indirect effect diagnosed here reaffirms the ability of volcanic aerosols to affect cloud properties and ultimately the planetary albedo.

  2. Automatic classification of pulmonary peri-fissural nodules in computed tomography using an ensemble of 2D views and a convolutional neural network out-of-the-box.

    PubMed

    Ciompi, Francesco; de Hoop, Bartjan; van Riel, Sarah J; Chung, Kaman; Scholten, Ernst Th; Oudkerk, Matthijs; de Jong, Pim A; Prokop, Mathias; van Ginneken, Bram

    2015-12-01

    In this paper, we tackle the problem of automatic classification of pulmonary peri-fissural nodules (PFNs). The classification problem is formulated as a machine learning approach, where detected nodule candidates are classified as PFNs or non-PFNs. Supervised learning is used, where a classifier is trained to label the detected nodule. The classification of the nodule in 3D is formulated as an ensemble of classifiers trained to recognize PFNs based on 2D views of the nodule. In order to describe nodule morphology in 2D views, we use the output of a pre-trained convolutional neural network known as OverFeat. We compare our approach with a recently presented descriptor of pulmonary nodule morphology, namely Bag of Frequencies, and illustrate the advantages offered by the two strategies, achieving performance of AUC = 0.868, which is close to the one of human experts. PMID:26458112

  3. Automatic classification of pulmonary peri-fissural nodules in computed tomography using an ensemble of 2D views and a convolutional neural network out-of-the-box.

    PubMed

    Ciompi, Francesco; de Hoop, Bartjan; van Riel, Sarah J; Chung, Kaman; Scholten, Ernst Th; Oudkerk, Matthijs; de Jong, Pim A; Prokop, Mathias; van Ginneken, Bram

    2015-12-01

    In this paper, we tackle the problem of automatic classification of pulmonary peri-fissural nodules (PFNs). The classification problem is formulated as a machine learning approach, where detected nodule candidates are classified as PFNs or non-PFNs. Supervised learning is used, where a classifier is trained to label the detected nodule. The classification of the nodule in 3D is formulated as an ensemble of classifiers trained to recognize PFNs based on 2D views of the nodule. In order to describe nodule morphology in 2D views, we use the output of a pre-trained convolutional neural network known as OverFeat. We compare our approach with a recently presented descriptor of pulmonary nodule morphology, namely Bag of Frequencies, and illustrate the advantages offered by the two strategies, achieving performance of AUC = 0.868, which is close to the one of human experts.

  4. A Comparative Evaluation of the Effect of Bonding Agent on the Tensile Bond Strength of Two Pit and Fissure Sealants Using Invasive and Non-invasive Techniques: An in–vitro Study

    PubMed Central

    Singh, Shamsher; Adlakha, Vivek; Babaji, Prashant; Chandna, Preetika; Thomas, Abi M.; Chopra, Saroj

    2013-01-01

    Background: Newer technologies and the development of pit and fissure sealants have shifted the treatment philosophy from ‘drill and fill’ to that of ‘seal and heal’. Aims: The purpose of this in–vitro study was to evaluate the effects of bonding agents on the tensile bond strengths of two pit and fissure sealants by using invasive and non-invasive techniques. Study Design and Methods: One hundred and twenty bicuspids were collected and teeth were divided into two groups: Group-I (Clinpro) and Group-II (Conseal f) with 60 teeth in each group. For evaluating tensile bond strengths, occlusal surfaces of all the teeth were flattened by reducing buccal and lingual cusps without disturbing fissures. Standardised polyvinyl tube was bonded to occlusal surfaces with respective materials. Sealants were applied, with or without bonding agents, in increments and they were light cured. Tensile bond strengths were determined by using Universal Testing Machine. Statistical Analysis: Data were then statistically analysed by using Student t–test for comparison. Results: A statistically significant difference was found in tensile bond strength in invasive with bonding agent group than in non-invasive with bonding agent group. Conclusion: This study revealed that invasive techniques increase the tensile bond strengths of sealants as compared to non- invasive techniques and that the use of a bonding agent as an intermediate layer between the tooth and fissure sealant is beneficial for increasing the bond strength. PMID:24298525

  5. Effect of the application of a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste and adhesive systems on bond durability of a fissure sealant.

    PubMed

    Borges, Boniek Castillo Dutra; Catelan, Anderson; Sasaki, Robson Tetsuo; Ambrosano, Gláucia Maria Bovi; Reis, André Figueiredo; Aguiar, Flávio Henrique Baggio

    2013-01-01

    This study aimed to evaluate the effect of the previous application of a casein phosphopeptide-amorphous calcium phosphate paste (MI Paste, MI) and adhesive systems on the bond durability of a fissure sealant. Ninety-eight enamel blocks were obtained from proximal surfaces of erupted third molars. Specimens were divided into 14 groups (n = 7) according to the previous application of MI (with and without) and the adhesive systems used (no adhesive system; hydrophobic resin of a three-step etch-and-rinse adhesive system; etch-and-rinse single-bottle adhesive system; all-in-one adhesive system; two-step self-etching adhesive system; additional phosphoric acid conditioning and all-in-one adhesive system; additional phosphoric acid conditioning and two-step self-etching adhesive system). A fissure sealant (Fluroshield) was applied and photoactivated for 20 s. Beams (~0.7 mm(2)) were prepared for the microtensile bond strength test, which was executed after 24 h or 6 months of water storage. Fractured specimens were analyzed by scanning electronic microscopy. Data were analyzed by two-way ANOVA with repeated measures/Tukey's test (P < 0.05). Groups that received MI application and adhesive systems presented higher means than those groups where MI was not applied. Higher frequency of cohesive failures was observed for groups with MI. Applying a CPP-ACP containing paste on enamel before adhesive systems was an effective method to increase bond durability of the sealant tested.

  6. Application of Bistatic TanDEM-X Interferometry to Measure Lava Flow Volume and Lava Extrusion Rates During the 2012-13 Tolbachik, Kamchatka Fissure Eruption

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2015-12-01

    Aerial imaging methods are a well approved source for mapping lava flows during eruptions and can serve as a base to assess the eruption dynamics and to determine the affected area. However, clouds and smoke often hinder optical systems like the Earth Observation Advanced Land Imager (EO-1-ALI, operated by NASA) to map lava flows properly, which hence affects its reliability. Furthermore, the amount of lava that is extruded during an eruption cannot be determined from optical images - however, it can significantly contribute to assess the accompanying hazard and risk. One way to monitor active lava flows is to quantify the topographic changes over time while using up-to-date high-resolution digital elevation models (DEMs). Whereas photogrammetric methods still fail when clouds and fume obstruct the sight, innovative radar satellite missions have the potential to generate high-resolution DEMs at any time. The innovative bistatic TanDEM-X (TerraSAR-X Add-on for Digital Elevation Measurements) satellite mission enables for the first time generating high-resolution DEMs from synthetic aperture radar satellite data repeatedly with reasonable costs and high resolution. The satellite mission consists of the two nearly identical satellites TerraSAR-X and TanDEM-X that build a large synthetic aperture radar interferometer with adaptable across- and along-track baselines aiming to generate topographic information globally. In the present study, we apply the TanDEM-X data to study the lava flows that were emplaced during the 2012-13 Tolbachik, Kamchatka fissure eruption. The eruption was composed of very fluid lava flows that effused along a northeast-southwest trending fissure. We used about fifteen bistatic data pairs to generate DEMs prior to, during, and after the eruption. The differencing of the DEMs enables mapping the lava flow field at different times. This allows measuring the extruded volume and to derive the changes in lava extrusion over time.

  7. Tbx18 and boundary formation in chick somite and wing development.

    PubMed

    Tanaka, Mikiko; Tickle, Cheryll

    2004-04-15

    The chicken Tbx gene, Tbx18, is expressed in lateral plate mesoderm, limb, and developing somites. Here we show that Tbx18 is expressed transiently in axial mesenchyme during somite segmentation. We present evidence from overexpression and transplantation experiments that Tbx18 controls fissure formation in the late stages of somite maturation. In presumptive wing lateral plate mesoderm, ectopic Tbx18 expression leads to anterior extension of the wing bud. These results suggest that Tbx18 is involved in producing mesodermal boundaries, generating in paraxial mesoderm morphological boundaries between somites and in lateral plate mesoderm a wing- or non-wing-forming boundary.

  8. Simulating the propagation of sulphur dioxide emissions from the fissure eruption in the Holuhraun lava field (Iceland) with the EURAD-IM

    NASA Astrophysics Data System (ADS)

    Fröhlich, Luise; Franke, Philipp; Friese, Elmar; Haas, Sarah; Lange, Anne Caroline; Elbern, Hendrik

    2015-04-01

    In the emergency case of a volcano eruption accurate forecasts of the transport of ash and gas emissions are crucial for health protection and aviation safety. In the frame of Earth System Knowledge Platform (ESKP) near real-time forecasts of ash and SO2 dispersion emitted by active volcanoes are simulated by the European Air pollution Dispersion Inverse Model (EURAD-IM). The model is driven by the Weather Research and Forecasting Model (WRF) and includes detailed gas phase and particle dynamics modules, which allow for quantitative estimates of measured volcano releases. Former simulations, for example related to the Eyjafjallajökull outbreak in 2010, were in good agreement with measurement records of particle number and SO2 at several European stations. At the end of August 2014 an fissure eruption has begun on Iceland in the Holuhraun lava field to the north-east of the Bardarbunga volcano system. In contrast to the explosive eruption of the Eyjafjallajökull in 2010, the Holuhraun eruption is rather effusive with a large and continuous flow of lava and a significant release of sulphur dioxide (SO2) in the lower troposphere, while ash emissions are insignificant. Since the Holuhraun fissure eruption has started, daily forecasts of SO2 dispersion are produced for the European region (15 km horizontal resolution grid) and published on our website (http://apps.fz-juelich.de/iek-8/RIU/vorhersage_node.php). To simulate the transport of volcanic emissions, realistic source terms like mass release rates of ash and SO2 or plume heights are required. Since no representative measurements are currently available for the simulations, rough qualitative assumptions, based on reports from the Icelandic Met Office (IMO), are used. However, frequent comparisons with satellite observations show that the actual propagation of the volcanic emissions is generally well reflected by the model. In the middle of September 2014 several European measurement sides recorded extremely high

  9. A model study of the pollution effects of the first 3 months of the Holuhraun volcanic fissure: comparison with observations and air pollution effects

    NASA Astrophysics Data System (ADS)

    Steensen, Birthe Marie; Schulz, Michael; Theys, Nicolas; Fagerli, Hilde

    2016-08-01

    The volcanic fissure at Holuhraun, Iceland started at the end of August 2014 and continued for 6 months to the end of February 2015, with an extensive lava flow onto the Holuhraun plain. This event was associated with large SO2 emissions, amounting up to approximately 4.5 times the daily anthropogenic SO2 emitted from the 28 European Union countries, Norway, Switzerland and Iceland. In this paper we present results from EMEP/MSC-W model simulations to which we added 750 kg s-1 SO2 emissions at the Holuhraun plain from September to November (SON), testing three different emission heights. The three simulated SO2 concentrations, weighted with the OMI (Ozone Monitoring Instrument) satellite averaging kernel, are found to be within 30 % of the satellite-observed SO2 column burden. Constraining the SO2 column burden with the satellite data while using the kernel along with the three simulated height distributions of SO2, we estimate that the median of the daily burdens may have been between 13 and 40 kt in the North Atlantic area under investigation. We suggest this to be the uncertainty in the satellite-derived burdens of SO2, mainly due to the unknown vertical distribution of SO2. Surface observations in Europe outside Iceland showed concentration increases up to > 500 µg m-3 SO2 from volcanic plumes passing. Three well identified episodes, where the plume crossed several countries, are compared in detail to surface measurements. For all events, the general timing of the observed concentration peaks compared quite well to the model results. The overall changes to the European SO2 budget due to the volcanic fissure are estimated. Three-monthly wet deposition (SON) of SOx in the 28 European Union countries, Norway and Switzerland is found to be more than 30 % higher in the model simulation with Holuhraun emissions compared to a model simulation with no Holuhraun emissions. The largest increases, apart from extreme values on Iceland, are found on the coast of northern

  10. Vesicle size analysis of magmatic and phreatomagmatic phases of the 934-40 AD Eldgjá fissure eruption, southern Iceland

    NASA Astrophysics Data System (ADS)

    Thordarson, T.; Moreland, W.; Houghton, B. F.

    2014-12-01

    Eldgjá is a ~75 km volcanic fissure which erupted in the middle of the 10th century. It belongs to the Katla volcanic system and is of the mixed-cone row type. The eruption lasted several years and produced two large lava fields (18.3 km3) and a widespread basaltic tephra deposit (4.5 km3 or 1.3 km3 DRE). Proximal tephra deposits are up to 5 m thick and contain as many as 10 sub-units which vary in thickness parallel to the fissure, indicating multiple points of origin. Many of the lowest units were produced by phreatomagmatic activity and dispersion of these units indicate an origin below the Mýrdalsjökull glacier. Two sections were chosen to represent magmatic and phreatomagmatic activity. A 3.7 m section at Skælingar, 0.5 km south-east of Eldgjá, represents the magmatic products. The phreatomagmatic products are represented by a 2.7 m thick section at Stóragil, located 10-15 km south and east of the vent system. The sampled phreatomagmatic part of the section is 1.12 m thick. These sections were logged and then each sub-unit was sampled for density analysis which involves picking 100 clasts in the 8 to 32 mm size range from horizons less than 5 cm thick. Thin-sections were then made from representative clasts of each sub-unit. Nested images of these thin-sections were analysed for vesicle size and shape. The magmatic clasts have unimodal, normal to moderately log-normal density distributions with a mean density of 7900-7500 kg.m-3 (60-70% vesicularity) and a range of around 8600 kg.m-3 (40% vesicularity). The log-normal distribution of some samples may be explained by the inclusion of previously degassed magma in the eruption. The section at Stóragil contains both phreatomagmatic and magmatic products. The phreatomagmatic samples have characteristic plateau-like distributions with a mean density of 7200-7500 kg.m-3 (70-80% vesicularity) and a range of around 8420 kg.m-3 (45% vesicularity). One layer shows a change from phreatomagmatic to magmatic

  11. Comparison of operational satellite SO2 products with ground-based observations in northern Finland during the Icelandic Holuhraun fissure eruption

    NASA Astrophysics Data System (ADS)

    Ialongo, I.; Hakkarainen, J.; Kivi, R.; Anttila, P.; Krotkov, N. A.; Yang, K.; Li, C.; Tukiainen, S.; Hassinen, S.; Tamminen, J.

    2015-06-01

    This paper shows the results of the comparison of satellite SO2 observations from OMI (Ozone Monitoring Instrument) and OMPS (Ozone Mapping Profiler Suite) with ground-based measurements during the Icelandic Holuhraun fissure eruption in September 2014. The volcanic plume reached Finland on several days during the month of September. The SO2 total columns from the Brewer direct sun (DS) measurements in Sodankylä (67.42° N, 26.59° E), northern Finland, are compared to the satellite data. The operational satellite SO2 products are evaluated for high latitude conditions (e.g. large solar zenith angle, SZA). The results show that the best agreement can be found for lowest SZAs, close-to-nadir satellite pixels, cloud fraction below 0.3 and small distance between the station and the centre of the pixel. Under good retrieval conditions, the difference between satellite data and Brewer measurements remains mostly below the uncertainty on the satellite SO2 retrievals (up to about 2 DU at high latitudes). The satellite products assuming a priori profile with SO2 predominantly in the planetary boundary layer give total column values with the best agreement with the ground-based data. The analysis of the SO2 surface concentrations at four air quality stations in northern Finland shows that the volcanic plume coming from Iceland was located very close to the surface. This is connected to the fact that this was a fissure eruption and most of the SO2 was emitted into the troposphere. This is an exceptional case because the SO2 volcanic emissions directly affect the air quality levels at surface in an otherwise pristine environment like northern Finland. The time evolution of the SO2 concentrations peaks during the same days when large SO2 total column values are measured by the Brewer in Sodankylä and enhanced SO2 signal is visible over northern Finland from the satellite maps. Thus, the satellite retrievals were able to detect the spatiotemporal evolution of the volcanic

  12. Source process of long-period seismic events at Taal volcano, Philippines: Vapor transportation and condensation in a shallow hydrothermal fissure

    NASA Astrophysics Data System (ADS)

    Maeda, Yuta; Kumagai, Hiroyuki; Lacson, Rudy; Figueroa, Melquiades S.; Yamashina, Tadashi

    2013-06-01

    We analyzed observations of a swarm of more than 40,000 long-period (LP) seismic events at Taal volcano, Philippines, in 2010-2011. The event waveforms are strongly correlated to each other, consistent with a fixed source location, and begin with a dilatational first motion. They have a peak frequency around 0.8 Hz and a quality factor Q of 6. Waveform inversion of the events pointed to a tensile crack source dipping 30°-60° at a shallow (100-200 m) depth. A simulation using a fluid-filled crack model indicated that the complex frequencies of the waveforms are explained by the fundamental longitudinal mode resonance of a vapor-filled crack 188 m long. A satellite thermal infrared image acquired during the swarm period suggests that the LP events were not accompanied by surface gas releases. We considered a vapor transportation model in which vapor exsolved from magma and rose in a fissure extending to the LP source. This model yielded estimates that 105-107 m3 of magma was involved in the LP swarm and that the temperature of vapor in the LP source crack was around 600 K. We modeled a triggering mechanism of the crack resonance based on sudden condensation of vapor at the crack tip in a cold aquifer. This model explained observed characteristics of the events including the dilatational first motion, the total volumetric change, and the fixed source location.

  13. Étude micromécanique de la disparition du seuil de fissuration par fatigue d'un alliage de titane biphasé à fort K_{max}

    NASA Astrophysics Data System (ADS)

    Mignot, F.; Doquet, V.; Sarrazin-Baudoux, C.; Petit, J.

    2003-03-01

    L'alliage Ti6246 présente, lors d'essais de fissuration par fatigue à K_{max} constant et ΔK décroissant un comportement atypique : lorsque K_{max}ge 0.7KIC, on observe, sous air comme sous vide, au lieu du seuil attendu, un régime de propagation à vitesse constante, dix fois plus élevée à l'ambiante qu'à 500^{circ}C. Le fluage, qui se manifeste dès l'ambiante dans cet alliage semble jouer un rôle dans ce phénomène. Toutefois, des analyses par spectrométrie de masse d'ions secondaires font apparaître une sur-concentration en hydrogène au voisinage d'une fissure développée dans le régime anormal. Des essais de fissuration, traction et fluage sont donc entrepris sur le matériau brut, appauvri ou enrichi en hydrogène, pour partie dans la chambre d'un microscope électronique à balayage, dans le but d'explorer ce phénomène. On constate qu'un enrichissement en hydrogène augmente la ductilité du matériau et sa tendance au fluage à l'ambiante et un enrichissement plus prononcé la diminue.

  14. Effects of glass ionomer cement, resin-based pit and fissure sealant and HF applications on occlusal caries in a developing country field trial.

    PubMed

    Songpaisan, Y; Bratthall, D; Phantumvanit, P; Somridhivej, Y

    1995-02-01

    The aim of this community-oriented study was to evaluate different methods to prevent fissure caries. The following products and measures were tested: 1) glass ionomer cement (GIC) applied by dentist; 2) same material applied by short term (3 days) trained personnel (teachers); 3) application of a 0.5% HF solution three times; 4) an established autopolymerized resin based sealant (Delton). The study was performed in Bangkok, Thailand, a city in a developing country experiencing increasing caries prevalence. Children with at least three sound permanent molars from two age groups, 7-8 and 12-13-yr-olds respectively were chosen from very low to medium socioeconomic level families. 1264 children were systematically assigned to experiment or control groups based on school and DMFT. For the younger age group, the 2 yr mean DFS occlusal increment in the Control group was 0.66 surfaces. Significantly lower increments were observed in the GIC experimental group: 0.17 surfaces applied by the teachers and 0.32 applied by dentist, corresponding to 74% and 52% reductions, respectively. The mean increment in the HF group was 0.44 surfaces, a 33% reduction in relation to the Control group. For the 12-13-yr-olds, the mean occlusal surface DF increment was 0.70 surfaces in the Control group. Almost no occlusal increment was found in the Delton group, 0.05 DFS, a 93% reduction. In the GIC Dentist group, the DFS increment was 0.48 and in the Teacher group 0.56, corresponding to 31% and 20% reduction, respectively. A slight and nonsignificant increase of caries in relation to the Control group was observed in the HF group.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Microsurgical management of pediatric ependymomas of the fourth ventricle via the trans-cerebellomedullary fissure approach: A review of 26 cases

    PubMed Central

    QIU, BO; WANG, YONG; WANG, WEI; WANG, CHAO; WU, PENGFEI; BAO, YIJUN; OU, SHAOWU; GUO, ZONGZE; WANG, YUNJIE

    2016-01-01

    In the present study, the microsurgical management of 26 ependymomas of the fourth ventricle in children via the trans-cerebellomedullary fissure (CMF) approach was reviewed and evaluated. Clinical data were obtained from 26 ependymomas of the fourth ventricle treated with microsurgery using the trans-CMF approach from March 2006 to September 2010 at the Department of Neurosurgery of The First Affiliated Hospital of China Medical University (Shenyang, China). These data were collected and analyzed. Suboccipital median posterior fossa craniotomy and trans-CMF approach were performed in all cases for the microsurgical removal of the tumors. An additional incision was performed in the inferior medullary velum of 5 patients, in order to obtain adequate exposure of the tumors. As a result, all tumors were well exposed during surgery. Gross total resection (GTR) was achieved in 22 cases, near total resection (NTR) in 3 cases and subtotal resection (STR) in 1 case. All excised tumors were pathologically confirmed. No mortality occurred intraoperatively, and no patient presented with mutism or any other surgery-related complications. One patient suffered from postoperative hydrocephalus and received ventriculoperitoneal shunting, which relieved the symptoms. Over the 3.0–7.5-year follow-up period (mean, 4.8 years), tumor relapse occurred in 1 case with GTR, 2 cases with NTR and 1 case with STR. In total, 3 patients succumbed to tumor relapse and 4 were lost to follow-up. According to the literature and the clinical experience of the present authors, the trans-CMF approach provides safe and sufficient access to the fourth ventricle without the requirement of an incision in the inferior vermis. This approach prevents damage to the normal cerebellum and improves the surgical outcome. Tumor removal, restoration of cerebrospinal fluid circulation and preservation of brainstem function are factors that should be taken into consideration during surgery. For patients with

  16. Nitroglycerin 0.4% ointment vs placebo in the treatment of pain resulting from chronic anal fissure: a randomized, double-blind, placebo-controlled study

    PubMed Central

    2013-01-01

    Background Complications of chronic anal fissure (CAF) treatments are prompting interest in lower-risk therapies. This study was conducted to compare nitroglycerin (NTG) 0.4% ointment with placebo for pain associated with CAF. Methods In this randomized, double-blind, placebo-controlled trial, patients with one CAF and moderate-to-severe pain (≥50 mm on a 100 mm visual analog scale [VAS]) received 375 mg NTG 0.4% (1.5 mg active ingredient) or 375 mg placebo ointment applied anally every 12 hours for 21 days. The primary end point was change from baseline VAS score in 24-hour pain averaged over days 14–18. Review of data from patients who withdrew early was blinded to treatment. To control for the confounding effects of analgesics, all patients received 650 mg acetaminophen for headache prophylaxis before each application. Results A total of 247 patients were enrolled (NTG, n = 123; placebo, n = 124). The prespecified baseline observation carried forward (BOCF) analysis found no significant difference between groups; however, a last observation carried forward (LOCF) analysis showed a significant advantage for NTG. A post hoc analysis (LOCF/BOCF hybrid) demonstrated a significant adjusted mean difference of −7.0 mm in favor of NTG 0.4% (95% CI −13.6, –0.4; P = .038). Headache was the most common adverse event in the NTG (69.9%) and placebo (47.6%) groups. Conclusions This was the first placebo-controlled study that also controlled for the confounding effects of analgesics used to treat NTG-induced headache. In patients with moderate-to-severe CAF pain, NTG 0.4% ointment effectively reduced CAF pain compared with placebo. Trial registration ClinicalTrials.gov, NCT00522041 PMID:23815124

  17. Comet formation

    NASA Astrophysics Data System (ADS)

    Blum, J.

    2014-07-01

    There has been vast progress in our understanding of planetesimal formation over the past decades, owing to a number of laboratory experiments as well as to refined models of dust and ice agglomeration in protoplanetary disks. Coagulation rapidly forms cm-sized ''pebbles'' by direct sticking in collisions at low velocities (Güttler et al. 2010; Zsom et al. 2010). For the further growth, two model approaches are currently being discussed: (1) Local concentration of pebbles in nebular instabilities until gravitational instability occurs (Johansen et al. 2007). (2) A competition between fragmentation and mass transfer in collisions among the dusty bodies, in which a few ''lucky winners'' make it to planetesimal sizes (Windmark et al. 2012a,b; Garaud et al. 2013). Predictions of the physical properties of the resulting bodies in both models allow a distinction of the two formation scenarios of planetesimals. In particular, the tensile strength (i.e, the inner cohesion) of the planetesimals differ widely between the two models (Skorov & Blum 2012; Blum et al. 2014). While model (1) predicts tensile strengths on the order of ˜ 1 Pa, model (2) results in rather compactified dusty bodies with tensile strengths in the kPa regime. If comets are km-sized survivors of the planetesimal-formation era, they should in principle hold the secret of their formation process. Water ice is the prime volatile responsible for the activity of comets. Thermophysical models of the heat and mass transport close to the comet-nucleus surface predict water-ice sublimation temperatures that relate to maximum sublimation pressures well below the kPa regime predicted for formation scenario (2). Model (1), however, is in agreement with the observed dust and gas activity of comets. Thus, a formation scenario for cometesimals involving gravitational instability is favored (Blum et al. 2014).

  18. Planet Formation

    NASA Astrophysics Data System (ADS)

    Klahr, Hubert; Brandner, Wolfgang

    2011-02-01

    1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

  19. Galaxy formation.

    PubMed

    Peebles, P J

    1998-01-01

    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z approximately 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation.

  20. Galaxy formation

    PubMed Central

    Peebles, P. J. E.

    1998-01-01

    It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z ∼ 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation. PMID:9419326

  1. Effect of occlusal calculus utilized as a potential "biological sealant" in special needs patients with gastric feeding tubes: a qualitative in vitro contrast to pit and fissure sealant restorations.

    PubMed

    Owens, Barry M; Sharp, Harry K; Fourmy, Emily E; Phebus, Jeffrey G

    2016-01-01

    The aim of this case report and in vitro investigation was to evaluate the marginal microleakage of intact occlusal calculus of primary molars extracted from a special needs patient who received nutrition via a gastric feeding tube. An adolescent with a history of developmental disturbance presented for routine dental care in a hospital facility. Prophylaxis was performed, and 2 mandibular permanent molars were restored. Five primary molars were extracted due to mobility and delayed retention. Heavy deposits of intact calculus were present on the occlusal surfaces of the primary teeth. The extracted teeth were immersed in methylene blue dye solution, invested in acrylic resin, sectioned into blocks, and photographed at 20× and 40× magnification. Previously photographed calculus-free molars with pit and fissure sealants were reviewed and served as contrasting "restorations." The occlusal calculus on the primary teeth extracted from the patient absorbed the dye, while the comparison teeth containing pit and fissure sealants exhibited varying degrees of marginal dye penetration (microleakage). No marginal microleakage was noted in the calculus specimens, indicating that this substrate may serve as a "natural" occlusal surface sealant and that its removal from occlusal surfaces during routine oral prophylaxis may be unnecessary. PMID:27367629

  2. The feeder system for the 2014 fissure eruption at Holuhraun, Bárðarbunga volcanic system, Iceland: Geodetic and seismic constraints on subsurface activity in the area north of the Vatnajökull ice cap

    NASA Astrophysics Data System (ADS)

    Dumont, Stéphanie; Parks, Michelle; Sigmundsson, Freysteinn; Hooper, Andy; Hreinsdóttir, Sigrun; Ófeigsson, Benedikt; Spaans, Karsten; Vogfjörd, Kristin; Jónsdóttir, Kristín; Hensch, Martin; Gudmundsson, Gunnar; Rafn Heimisson, Elias; Drouin, Vincent; Árnadóttir, Thóra; Pedersen, Rikke; Rut Hjartardóttir, Ásta; Magnússon, Eyjólfur

    2015-04-01

    An intense earthquake swarm began on 16 August 2014 at Bárðarbunga volcano under the Vatnajökull ice cap in Central Iceland. It marked the beginning of an intrusive activity, with a dyke propagating over 45 km northward. Such major magmatic activity has not been observed for the last three decades in Iceland, since the Krafla rifting episode 1975-1984. The dyke propagation stopped 15 days after the onset of the seismic activity, with the dyke distal end in the Holuhraun plain north of the Vatnajökull ice cap. A small 4 hour eruption marked the beginning of extrusive activity. A new fissure eruption opened up on 31 August at the northern dyke tip, with lava fountaining and feeding extensive lava flows. In January 2014 the surface covered by the lava had exceeded 80 km2, and the eruption activity does not show significant decline. We have carried out interferometric analysis of SAR data (InSAR) since the onset of the unrest. X-band satellite images from COSMO-SkyMed and TerraSAR-X satellites were acquired and analyzed to map ground surface deformation associated with the dyke emplacement. Despite most of the dyke propagation occurring under several hundreds meters of ice, the last 10 km were outside the ice cap, allowing better characterisation of the dyke-induced deformation. Here we focus on the deformation in the Holuhraun plain, in order to better understand the link between the surface deformation detected in the vicinity of the dyke by InSAR as well as GPS measurements, and the eruptive activity. The regular SAR acquisitions made over the Holuhraun area since the beginning of the unrest offer a unique opportunity to better understand the evolution of the intrusion feeding the fissure eruption. For that purpose, we focus on the faults and fissures forming the graben borders on the glacier as well as in the Holuhraun plain, initially mapped using high-resolution radar images, acquired by airborne radar. We extract movement along and perpendicular to these

  3. New volcanogenic-eruptive genetic type of diamond occurrence (based on studying the 2012-2013 Fissure Tolbachik Eruption in Kamchatka)

    NASA Astrophysics Data System (ADS)

    Karpov, Gennady; Anikin, Leonid; Filatov, Stanislav; Silaev, Valery; Petrovsky, Vitaly; Zolotarev, Andrey; Dunin-Barkovsky, Romuald; Volynets, Anna

    2014-05-01

    During the 2012-2013 Fissure Tolbachik eruption, diamonds were found both in fresh pyroclastics and in the effusive lava pores. Lavas are aphyric and subaphyric porous aluminous basaltic trachyandesites with rare megacrysts and subphenocrysts of plagioclase, olivine and pyroxene. Groundmass is hyalopilitic, pilotaxitic, occasionally hyaline, with abundant plagioclase microlites. So far, over 750 diamond grains have been found sized mostly 100-500 mkm. Generally, grains are well formed isometric, plane-faced and sharp-edged monocrystals of cubic-octahedral habit and green color, rarer colorless. Faces of rhombic-dodecahedron, tetragonal-trisoctahedron and trigonal-trisoctahedron also occur. Crystal cubic faces host pits of diffusive depletion, and pits with induction surfaces formed after the breakoff of syngenetic inclusions. Octahedral faces often show pyramidal etching pits formed at the dislocation outcrops. Pits contain coatings whose composition includes Fe, Mg, Ca, Si, and Cu-Sn (Zn) alloy films. Diamond X-ray diffraction data (Bruker APEX DUO, STOE IPDS II, MoKα-radiation, 788 reflections) show space group Fd-3m, cubic unit cell parameter a = 3.574(3) A and major reflections (111), (220), (311) etc. at Gandolfi pattern. Raman spectra with red beam reveal only one strong line at 1332 cm-1 typical for diamonds. Spectra excited by the 785 nm beam reveal a wide line with the peak at 1370 cm-1, whose intensity oscillates from 1% to 70% of the diamond line intensity at 1332 cm-1. Infrared absorption spectra reflect two lines with peaks at 1345 and 1130 cm-1, corresponding to structural C-defects (isolated N atoms). Partially, these defects occur in the positive charge state - N+. Structural nitrogen concentration in the form of C-defects varies from 150 to 500 ppm, while that in the form of N+ - from 10 to 30 ppm. Lines of infrared absorption on A and B1 nitrogen defects, as well as those on hydrogen defects typical for most natural diamonds, are not detected for

  4. Amphiplex Formation

    NASA Astrophysics Data System (ADS)

    Petersen, Shannon; Laaser, Jennifer; Lodge, Timothy

    2015-03-01

    Polymer-micelle complexes are currently under heavy investigation due to their potential applications in targeted drug delivery and gene therapy, yet the dynamics of the complex formation is still relatively unstudied. By varying the ratios of poly(styrene sulfonate) chains and cationic poly(dimethylaminoethyl methacrylate)-b-poly(styrene) micelles and the ionic strength of the system, we created a variety of complex configurations of different sizes and charges. The complexes were characterized dynamic light scattering and zeta potential measurements which provided information regarding the hydrodynamic radius, distribution of sizes, and effective charge.

  5. Macro-permeability distribution and anisotropy in a 3D fissured and fractured clay rock: ‘Excavation Damaged Zone’ around a cylindrical drift in Callovo-Oxfordian Argilite (Bure)

    NASA Astrophysics Data System (ADS)

    Ababou, Rachid; Cañamón Valera, Israel; Poutrel, Adrien

    The Underground Research Laboratory at Bure (CMHM), operated by ANDRA, the French National Radioactive Waste Management Agency, was developed for studying the disposal of radioactive waste in a deep clayey geologic repository. It comprises a network of underground galleries in a 130 m thick layer of Callovo-Oxfordian clay rock (depths 400-600 m). This work focuses on hydraulic homogenization (permeability upscaling) of the Excavation Damaged Zone (EDZ) around a cylindrical drift, taking into account: (1) the permeability of the intact porous rock matrix; (2) the geometric structure of micro-fissures and small fractures synthesized as a statistical set of planar discs; (3) the curved shapes of large ‘chevron’ fractures induced by excavation (periodically distributed). The method used for hydraulic homogenization (upscaling) of the 3D porous and fractured rock is based on a ‘frozen gradient’ superposition of individual fluxes pertaining to each fracture/matrix block, or ‘unit block’. Each unit block comprises a prismatic block of permeable matrix (intact rock) obeying Darcy’s law, crossed by a single piece of planar fracture obeying either Darcy or Poiseuille law. Polygonal as well as disc shaped fractures are accommodated. The result of upscaling is a tensorial Darcy law, with macro-permeability K ij( x) distributed over a grid of upscaling sub-domains, or ‘voxels’. Alternatively, K ij( x) can be calculated point-wise using a moving window, e.g., for obtaining permeability profiles along ‘numerical’ boreholes. Because the permeable matrix is taken into account, the upscaling procedure can be implemented sequentially, as we do here: first, we embed the statistical fissures in the matrix, and secondly, we embed the large curved chevron fractures. The results of hydraulic upscaling are expressed first in terms of ‘equivalent’ macro-permeability tensors, K ij( x, y, z) distributed around the drift. The statistically isotropic fissures are

  6. Habit formation

    PubMed Central

    Smith, Kyle S.; Graybiel, Ann M.

    2016-01-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network. PMID:27069378

  7. Habit formation.

    PubMed

    Smith, Kyle S; Graybiel, Ann M

    2016-03-01

    Habits, both good ones and bad ones, are pervasive in animal behavior. Important frameworks have been developed to understand habits through psychological and neurobiological studies. This work has given us a rich understanding of brain networks that promote habits, and has also helped us to understand what constitutes a habitual behavior as opposed to a behavior that is more flexible and prospective. Mounting evidence from studies using neural recording methods suggests that habit formation is not a simple process. We review this evidence and take the position that habits could be sculpted from multiple dissociable changes in neural activity. These changes occur across multiple brain regions and even within single brain regions. This strategy of classifying components of a habit based on different brain signals provides a potentially useful new way to conceive of disorders that involve overly fixed behaviors as arising from different potential dysfunctions within the brain's habit network.

  8. Pattern Formation

    NASA Astrophysics Data System (ADS)

    Hoyle, Rebecca

    2006-03-01

    From the stripes of a zebra and the spots on a leopard's back to the ripples on a sandy beach or desert dune, regular patterns arise everywhere in nature. The appearance and evolution of these phenomena has been a focus of recent research activity across several disciplines. This book provides an introduction to the range of mathematical theory and methods used to analyse and explain these often intricate and beautiful patterns. Bringing together several different approaches, from group theoretic methods to envelope equations and theory of patterns in large-aspect ratio-systems, the book also provides insight behind the selection of one pattern over another. Suitable as an upper-undergraduate textbook for mathematics students or as a fascinating, engaging, and fully illustrated resource for readers in physics and biology, Rebecca Hoyle's book, using a non-partisan approach, unifies a range of techniques used by active researchers in this growing field. Accessible description of the mathematical theory behind fascinating pattern formation in areas such as biology, physics and materials science Collects recent research for the first time in an upper level textbook Features a number of exercises - with solutions online - and worked examples

  9. Barrier Formation

    PubMed Central

    Lyaruu, D.M.; Medina, J.F.; Sarvide, S.; Bervoets, T.J.M.; Everts, V.; DenBesten, P.; Smith, C.E.; Bronckers, A.L.J.J.

    2014-01-01

    Enamel fluorosis is an irreversible structural enamel defect following exposure to supraoptimal levels of fluoride during amelogenesis. We hypothesized that fluorosis is associated with excess release of protons during formation of hypermineralized lines in the mineralizing enamel matrix. We tested this concept by analyzing fluorotic enamel defects in wild-type mice and mice deficient in anion exchanger-2a,b (Ae2a,b), a transmembrane protein in maturation ameloblasts that exchanges extracellular Cl− for bicarbonate. Defects were more pronounced in fluorotic Ae2a,b−/− mice than in fluorotic heterozygous or wild-type mice. Phenotypes included a hypermineralized surface, extensive subsurface hypomineralization, and multiple hypermineralized lines in deeper enamel. Mineral content decreased in all fluoride-exposed and Ae2a,b−/− mice and was strongly correlated with Cl−. Exposure of enamel surfaces underlying maturation-stage ameloblasts to pH indicator dyes suggested the presence of diffusion barriers in fluorotic enamel. These results support the concept that fluoride stimulates hypermineralization at the mineralization front. This causes increased release of protons, which ameloblasts respond to by secreting more bicarbonates at the expense of Cl− levels in enamel. The fluoride-induced hypermineralized lines may form barriers that impede diffusion of proteins and mineral ions into the subsurface layers, thereby delaying biomineralization and causing retention of enamel matrix proteins. PMID:24170372

  10. Gingival fibromatosis with hemi-osseous hyperplasia of jaws, focal maxillary viral papillomatosis of gingiva, fissured tongue and congenitally missing anterior teeth: a case report and surgical management of a new syndrome.

    PubMed

    Reddy, M Sesha; Manyam, Ravikanth; Babu, M Narendera; Saraswathi, T R

    2011-01-01

    Gingival fibromatosis is characterized by fibrotic enlargement of the gingiva that can occur as inherited or sporadic form. Inherited form can be an isolated trait or as a component of a syndrome. This article reports a 35 year old male patient affected by gingival fibromatosis associated with hemiosseous hyperplasia of mandible, maxilla, and zygoma on the right side, viral papillomatosis of maxillary anterior gingiva, fissured tongue and congenitally missing anterior teeth. The patient was subjected to phase I and phase II periodontal therapy. There was no evidence of recurrence of the enlargement after one year but the papillomatosis recurred. Gingival fibromatosis has been reported to be associated with various other abnormalities but not with those described in our case. This observation raises the possibility that the coexistence of these entities in our case may represent a new syndrome.

  11. Selective ablation of pit and fissure caries from occlusal surfaces using λ=355-nm laser pulses and air-abrasion demonstrated using PS-OCT and near-IR imaging

    NASA Astrophysics Data System (ADS)

    Ross, Steven T.; Fan, Kenneth; Fried, Daniel

    2006-02-01

    Several past studies have suggested that lasers with and without added chromophores can be used for the selective removal of dental caries from stained pit and fissures in preparation for composite sealant placement with minimal damage to sound, unstained tooth structure. Polarization sensitive optical coherence tomography (PS-OCT) is a new nondestructive imaging technology that can be used to acquire images of caries lesions in occlusal surfaces. PSOCT is ideally suited to measure the caries depth and severity before and after selective removal from occlusal surfaces. In this study, λ=355-nm laser pulses of 5-ns duration at irradiation intensities ranging from 0.5-1.3 J/cm2 were scanned across tooth surfaces to selectively remove decayed enamel with and without the addition of India ink. PS-OCT images were acquired before and after removal. The laser removal was also compared to air abrasion in order to compare selectivity of these two conservative caries removal technologies.

  12. An unusual constellation of congenital malformations in a single patient including partial anomalous pulmonary venous return, persistent left superior vena cava, aberrant pulmonary fissure, anomalous aortic arch, tracheal diverticulum and annular pancreas

    PubMed Central

    Lapa, T; Vedelago, J; Kim, H; Patrick, E

    2014-01-01

    We report a case of a male patient with a constellation of rare congenital anomalies consisting of: partial anomalous pulmonary venous return (PAPVR), persistent left superior vena cava, ‘bovine arch’ aortic branching, tracheal diverticulum, aberrant lung fissure anatomy and an annular pancreas. He had presented with a history of worsening dyspnoea. To the best of our knowledge, this is the first reported case of a single patient with such a vast constellation of anomalies. The radiological evaluations, epidemiology, embryology and clinical features of the anomalies are discussed. It is important for radiologists to be aware of each of these anomalies as distinct entities; detection of a single anomaly should alert to the possibility that further anatomic aberrancies may be present. PMID:25362184

  13. An unusual constellation of congenital malformations in a single patient including partial anomalous pulmonary venous return, persistent left superior vena cava, aberrant pulmonary fissure, anomalous aortic arch, tracheal diverticulum and annular pancreas.

    PubMed

    Lapa, T; Vedelago, J; Kim, H; Patrick, E

    2014-10-31

    We report a case of a male patient with a constellation of rare congenital anomalies consisting of: partial anomalous pulmonary venous return (PAPVR), persistent left superior vena cava, 'bovine arch' aortic branching, tracheal diverticulum, aberrant lung fissure anatomy and an annular pancreas. He had presented with a history of worsening dyspnoea. To the best of our knowledge, this is the first reported case of a single patient with such a vast constellation of anomalies. The radiological evaluations, epidemiology, embryology and clinical features of the anomalies are discussed. It is important for radiologists to be aware of each of these anomalies as distinct entities; detection of a single anomaly should alert to the possibility that further anatomic aberrancies may be present.

  14. [Basic principles of structural asymmetry of cortex formations in the human brain].

    PubMed

    Bogolepova, I N; Malofeeva, L I

    2004-01-01

    Studying the cytoarchitectonical asymmetry of human brain cortex requires using the new approaches and modern quantitative methods. One of the promising ways is analyzing relation between the macroscopic and neuronal structure of the brain. The present article contains original data of histological and morphological studies. The authors develop the concept of different degree of expression of asymmetry in the cortex formations of left and right hemispheres. The data on the principal differences of topography and types of structure of fissure and gyrus in different brain hemispheres are presented. Results of the analysis carried out enable one to show the basic criteria of peculiarities of cytoarchitecture of human brain cortex in the left and right hemispheres. PMID:15455550

  15. Common File Formats.

    PubMed

    Mills, Lauren

    2014-03-21

    An overview of the many file formats commonly used in bioinformatics and genome sequence analysis is presented, including various data file formats, alignment file formats, and annotation file formats. Example workflows illustrate how some of the different file types are typically used.

  16. Formate Formation and Formate Conversion in Biological Fuels Production

    PubMed Central

    Crable, Bryan R.; Plugge, Caroline M.; McInerney, Michael J.; Stams, Alfons J. M.

    2011-01-01

    Biomethanation is a mature technology for fuel production. Fourth generation biofuels research will focus on sequestering CO2 and providing carbon-neutral or carbon-negative strategies to cope with dwindling fossil fuel supplies and environmental impact. Formate is an important intermediate in the methanogenic breakdown of complex organic material and serves as an important precursor for biological fuels production in the form of methane, hydrogen, and potentially methanol. Formate is produced by either CoA-dependent cleavage of pyruvate or enzymatic reduction of CO2 in an NADH- or ferredoxin-dependent manner. Formate is consumed through oxidation to CO2 and H2 or can be further reduced via the Wood-Ljungdahl pathway for carbon fixation or industrially for the production of methanol. Here, we review the enzymes involved in the interconversion of formate and discuss potential applications for biofuels production. PMID:21687599

  17. Graben formation during the Bárðarbunga rifting event in central Iceland

    NASA Astrophysics Data System (ADS)

    Ruch, Joël; Jónsson, Sigurjón; Wang, Teng; Xu, Wenbin; Trippanera, Daniele

    2015-04-01

    On the 16th of August 2014, an intense seismic swarm was detected at the Bárðarbunga caldera (central Iceland), which migrated to the east and then to the northeast during the following days. The swarm, highlighting magma propagation pathway from the caldera, migrated laterally during the following two weeks over 40 km. By the end of August, a volcanic eruption had started along a north-south oriented fissure located ~45 km from the caldera. Here we focus on the near-field deformation related to the dike emplacement in the shallow crust, which generated in few days an 8 km long by 0.8 km wide graben (depression) structure. The new graben extends from the northern edge of the Vatnajökull glacier and to the north to the eruptive fissure. We analyze the temporal evolution of the graben by integrating structural mapping using multiple acquisitions of TerraSAR-X amplitude radar images, InSAR and ground-truth data with GPS and structural measurements. Pixel-offset tracking of radar amplitude images shows clearly the graben subsidence, directly above the intrusion pathway, of up to 6 meters in the satellite line-of-sight direction. We installed a GPS profile of 15 points across the graben in October 2014 and measured its depth up to 8 meters, relative to the flanks of the graben. Field structural observations show graben collapse structures that typically accompany dike intrusions, with two tilted blocks dipping toward the graben axis, bordered by two normal faults. Extensive fractures at the center of the graben and at the graben edges show a cumulative extension of ~8 meters. The formation of the graben was also accompanied by strong seismic activity locally, constraining the time frame period of the main graben formation subsidence. Our results show a rare case of a graben formation captured from space and from ground observations. Such structures are the dominant features along rift zones, however, their formation remain poorly understood. The results also provide

  18. Fluid regimes during late stages of a continental collision: Physical, chemical, and stable isotope measurements of fluid inclusions in fissure quartz from a geotraverse through the Central Alps, Switzerland

    SciTech Connect

    Mullis, J. ); Dubessy, J.; Poty, B. ); O'Neil, J. )

    1994-05-01

    Fluid evolution during neo-alpine metamorphism during late stages of the continental collision between Europe and Africa was studied by analyzing fluid inclusions in alpine fissure quartz collected in forty-nine localities along a geotraverse through the Central Alps, Switzerland. The methods employed include microthermometry, micro-Raman spectroscopy, K/Na thermometry, and stable isotope analysis. Early fluid inclusions provide evidence of close to peak metamorphic temperatures of the late Tertiary or neo-alpine metamorphic event. Fluid composition evolved along the geotraverse from north to south as follows: higher hydrocarbons were dominant in the low- and medium-grade diagenetic zones, methane was the main volatile in the high-grade diagenetic and low-grade anchizone, water dominated in the high-grade anchizone and low-grade epizone, with CO[sub 2] > 10 mol% in the high-grade epizone and in the mesozone. Higher hydrocarbons and CH[sub 4] were the products of kerogen maturation and cracking of preexisting petroleum. Large water supplies originated from the dehydration of cooler metasedimentary rocks that were overthrust by crystalline basements of the Lepontines, Aar, and Gotthard massifs. Carbon isotope analyses suggest that the CO[sub 2] component was derived from oxidation of graphitic matter, especially in the vicinity of sulfate-bearing metasediments and from decarbonation reactions. In the Aar and Gotthard massifs as well as in the Helvetic Axen nappe and its underlying North Helvetic flysch, high fluid pressures prevailed and favored nappe transport. By contrast, in the southern Lepontine area, very low early fluid pressures were probably related to dry rocks and scarce metasediments, and to high geothermal gradients that resulted from intense uplift and erosion between 26 and 18 Ma.

  19. Hydrophilicity of dentin bonding systems influences in vitro Streptococcus mutans biofilm formation

    PubMed Central

    Brambilla, Eugenio; Ionescu, Andrei; Mazzoni, Annalisa; Cadenaro, Milena; Gagliani, Massimo; Ferraroni, Monica; Tay, Franklin; Pashley, David; Breschi, Lorenzo

    2014-01-01

    Objectives To evaluate in vitro Streptococcus mutans (S. mutans) biofilm formation on the surface of five light-curing experimental dental bonding systems (DBS) with increasing hydrophilicity. The null hypothesis tested was that resin chemical composition and hydrophilicity does not affect S. mutans biofilm formation. Methods Five light-curing versions of experimental resin blends with increasing hydrophilicity were investigated (R1, R2, R3, R4 and R5). R1 and R2 contained ethoxylated BisGMA/TEGDMA or BisGMA/TEGDMA, respectively, and were very hydrophobic, were representative of pit-and-fissure bonding agents. R3 was representative of a typical two-step etch- and-rinse adhesive, while R4 and R5 were very hydrophilic resins analogous to self-etching adhesives. Twenty-eight disks were prepared for each resin blend. After a 24 h-incubation at 37 °C, a multilayer monospecific biofilm of S. mutans was obtained on the surface of each disk. The adherent biomass was determined using the MTT assay and evaluated morphologically with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Results R2 and R3 surfaces showed the highest biofilm formation while R1 and R4 showed a similar intermediate biofilm formation. R5 was more hydrophilic and acidic and was significantly less colonized than all the other resins. A significant quadratic relationship between biofilm formation and hydrophilicity of the resin blends was found. CLSM and SEM evaluation confirmed MTT assay results. Conclusions The null hypothesis was rejected since S. mutans biofilm formation was influenced by hydrophilicity, surface acidity and chemical composition of the experimental resins. Further studies using a bioreactor are needed to confirm the results and clarify the role of the single factors. PMID:24954666

  20. The Format Dilemma.

    ERIC Educational Resources Information Center

    Oder, Norman

    2002-01-01

    Reports results of a survey of public libraries that investigated trends in audiovisual materials. Highlights include format issues; audiobooks; media budgets for various formats; video collections; DVDs; circulation; collection sizes; music CDs; and future possibilities. (LRW)

  1. Star Formation in Galaxies

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Topics addressed include: star formation; galactic infrared emission; molecular clouds; OB star luminosity; dust grains; IRAS observations; galactic disks; stellar formation in Magellanic clouds; irregular galaxies; spiral galaxies; starbursts; morphology of galactic centers; and far-infrared observations.

  2. Simple Ontology Format (SOFT)

    SciTech Connect

    Sorokine, Alexandre

    2011-10-01

    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layout system using customized styles.

  3. Record Formatting: MARC AMC.

    ERIC Educational Resources Information Center

    Weber, Lisa B.

    1990-01-01

    Discusses how archivists use the MARC AMC (Archival and Manuscripts Control) format for descriptive information about archival materials. Modifications that MARC AMC introduced to the standard MARC bibliographic formats are explained, and examples of a record in AMC formats on different bibliographic utilities are given. (24 references) (LRW)

  4. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

    Image file format is often a confusing aspect for someone wishing to process medical images. This article presents a demystifying overview of the major file formats currently used in medical imaging: Analyze, Neuroimaging Informatics Technology Initiative (Nifti), Minc, and Digital Imaging and Communications in Medicine (Dicom). Concepts common to all file formats, such as pixel depth, photometric interpretation, metadata, and pixel data, are first presented. Then, the characteristics and strengths of the various formats are discussed. The review concludes with some predictive considerations about the future trends in medical image file formats.

  5. Medical image file formats.

    PubMed

    Larobina, Michele; Murino, Loredana

    2014-04-01

    Image file format is often a confusing aspect for someone wishing to process medical images. This article presents a demystifying overview of the major file formats currently used in medical imaging: Analyze, Neuroimaging Informatics Technology Initiative (Nifti), Minc, and Digital Imaging and Communications in Medicine (Dicom). Concepts common to all file formats, such as pixel depth, photometric interpretation, metadata, and pixel data, are first presented. Then, the characteristics and strengths of the various formats are discussed. The review concludes with some predictive considerations about the future trends in medical image file formats. PMID:24338090

  6. Star Formation for Predictive Primordial Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Milosavljević, Miloš; Safranek-Shrader, Chalence

    The elegance of inflationary cosmology and cosmological perturbation theory ends with the formation of the first stars and galaxies, the initial sources of light that launched the phenomenologically rich process of cosmic reionization. Here we review the current understanding of early star formation, emphasizing unsolved problems and technical challenges. We begin with the first generation of stars to form after the Big Bang and trace how they influenced subsequent star formation. The onset of chemical enrichment coincided with a sharp increase in the overall physical complexity of star forming systems. Ab-initio computational treatments are just now entering the domain of the predictive and are establishing contact with local observations of the relics of this ancient epoch.

  7. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1993-01-15

    The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

  8. Earth fissures and localized differential subsidence

    USGS Publications Warehouse

    Holzer, Thomas L.; Pampeyan, Earl Haig

    1979-01-01

    Long tension cracks caused by declines of ground-water level at four sites in Arizona, California, and Nevada occur at points of maximum, convex-upward curvature in subsidence profiles based on relevelings of closely-spaced bench marks aligned perpendicular to the cracks. We conclude the cracks are caused by horizontal strains associated with the differential subsidence.

  9. Influence of Uncertain Parameters on the Leakage of CO2 to Overlying Formations

    NASA Astrophysics Data System (ADS)

    Gonzalez-Nicolas, A.; Cody, B. M.; Bau, D. A.

    2011-12-01

    In the last two centuries, atmospheric concentrations of carbon dioxide (CO2) have increased by about 35% as a result of anthropogenic emissions. To reduce these emissions, geologic Carbon Capture and Sequestration (CCS) has been advanced as an emerging technology. CCS involves the injection of CO2 in supercritical state into deep saline aquifers. Supercritical CO2 is less dense and less viscous than brine, which causes gravity override. If the retained CO2 finds a fault or abandoned well that leads to the surface, it may easily reach shallow groundwater resources or even the land surface affecting them prejudicially. The characterization of a potential site for storage of CO2 is typically a difficult task, given the uncertainties associated with the site properties of interest. Characteristics of the cap rock overlying the injected formations are decisive elements of a CCS system, especially its permeability and the spatial distribution of potential carbon escape pathways. In addition, leakage pathways may also be created during the CO2 injection process due to fissuring of the cap rock associated with the increased pore pressure and the ensuing effective stress reduction. Therefore, assessing the risk of leakage of CO2 given the uncertainty on the mentioned parameters is vital prior to the implementation of this technology. In this work, the variable parameters that are studied are: porosity and permeability of injected aquifers, cap rock permeability, as well as the location, size and permeability of carbon leakage pathways trough the sealing layers. Each of these parameters is associated to a statistical probability distribution function prescribed to represents typical ranges of variability. Several injection scenarios are investigated, which differ from one another depending on CO2 injection rates and time schedules. A semi-analytical model is used to simulate the injection of CO2 into a hypothetical deep saline aquifer overlain by a sequence of aquitards and

  10. Protocol for “Seal or Varnish?” (SoV) trial: a randomised controlled trial to measure the relative cost and effectiveness of pit and fissure sealants and fluoride varnish in preventing dental decay

    PubMed Central

    2012-01-01

    Background Dental caries remains a significant public health problem, prevalence being linked to social and economic deprivation. Occlusal surfaces of first permanent molars are the most susceptible site in the developing permanent dentition. Cochrane reviews have shown pit and fissure sealants (PFS) and fluoride varnish (FV) to be effective over no intervention in preventing caries. However, the comparative cost and effectiveness of these treatments is uncertain. The primary aim of the trial described in this protocol is to compare the clinical effectiveness of PFS and FV in preventing dental caries in first permanent molars in 6-7 year-olds. Secondary aims include: establishing the costs and the relative cost-effectiveness of PFS and FV delivered in a community/school setting; examining the impact of PFS and FV on children and their parents/carers in terms of quality of life/treatment acceptability measures; and examining the implementation of treatment in a community setting. Methods/design The trial design comprises a randomised, assessor-blinded, two-arm, parallel group trial in 6–7 year old schoolchildren. Clinical procedures and assessments will be performed at 66 primary schools, in deprived areas in South Wales. Treatments will be delivered via a mobile dental clinic. In total, 920 children will be recruited (460 per trial arm). At baseline and annually for 36 months dental caries will be recorded using the International Caries Detection and Assessment System (ICDAS) by trained and calibrated dentists. PFS and FV will be applied by trained dental hygienists. The FV will be applied at baseline, 6, 12, 18, 24 and 30 months. The PFS will be applied at baseline and re-examined at 6, 12, 18, 24, and 30 months, and will be re-applied if the existing sealant has become detached/is insufficient. The economic analysis will estimate the costs of providing the PFS versus FV. The process evaluation will assess implementation and acceptability through acceptability

  11. Simple Ontology Format (SOFT)

    2011-10-01

    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layoutmore » system using customized styles.« less

  12. GLOBAL STAR FORMATION REVISITED

    SciTech Connect

    Silk, Joseph; Norman, Colin E-mail: norman@stsci.edu

    2009-07-20

    A general treatment of disk star formation is developed from a dissipative multiphase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt (SK) law emerges naturally for star-forming disks and starbursts. We predict that there should be an inverse correlation between Tully-Fisher law and SK law residuals. The model is extended to include a multiphase treatment of supernova feedback that leads to a turbulent pressure-regulated generalization of the star formation law and is applicable to gas-rich starbursts. Enhanced pressure, as expected in merger-induced star formation, enhances star formation efficiency. An upper limit is derived for the disk star formation rate in starbursts that depends on the ratio of global ISM to cloud pressures. We extend these considerations to the case where the interstellar gas pressure in the inner galaxy is dominated by outflows from a central active galactic nucleus (AGN). During massive spheroid formation, AGN-driven winds trigger star formation, resulting in enhanced supernova feedback and outflows. The outflows are comparable to the AGN-boosted star formation rate and saturate in the super-Eddington limit. Downsizing of both SMBH and spheroids is a consequence of AGN-driven positive feedback. Bondi accretion feeds the central black hole with a specific accretion rate that is proportional to the black hole mass. AGN-enhanced star formation is mediated by turbulent pressure and relates spheroid star formation rate to black hole accretion rate. The relation between black hole mass and spheroid velocity dispersion has a coefficient (Salpeter time to gas consumption time ratio) that provides an arrow of time. Highly efficient, AGN-boosted star formation can occur at high redshift.

  13. [Measuring thrombin formation].

    PubMed

    Hemker, H C

    2016-01-01

    Measurement of thrombin formation makes it possible to estimate the risk of haemorrhage or thrombosis much more accurately than by using clotting time. This new technique allows better monitoring of the effect of prophylactic and therapeutic anticoagulant therapy. Thrombin formation is, however, not yet routinely measured. PMID:27650017

  14. Ice Formation on Wings

    NASA Technical Reports Server (NTRS)

    Ritz, L

    1939-01-01

    This report makes use of the results obtained in the Gottingen ice tunnel in which the atmospheric conditions are simulated and the process of ice formation photographed. The effect of ice formation is threefold: 1) added weight to the airplane; 2) a change in the lift and drag forces; 3) a change in the stability characteristics.

  15. School Formative Feedback Systems

    ERIC Educational Resources Information Center

    Halverson, Richard

    2010-01-01

    Data-driven instructional improvement relies on developing coherent systems that allow school staff to generate, interpret, and act upon quality formative information on students and school programs. This article offers a formative feedback system model that captures how school leaders and teachers structure artifacts and practices to create…

  16. Entering the Formative Years

    ERIC Educational Resources Information Center

    Powers, Keith

    2011-01-01

    This article discusses formative assessment--classroom strategies that ensure students are understanding music concepts. Unlike summative assessments (end-of-process evaluations like final exams, SATs, or auditions), formative assessments need to be non-threatening, helpful, and most of all, effective. The process starts with a teacher…

  17. Formative Assessment Probes

    ERIC Educational Resources Information Center

    Eberle, Francis; Keeley, Page

    2008-01-01

    Formative assessment probes can be effective tools to help teachers build a bridge between students' initial ideas and scientific ones. In this article, the authors describe how using two formative assessment probes can help teachers determine the extent to which students make similar connections between developing a concept of matter and a…

  18. Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

    NASA Astrophysics Data System (ADS)

    Jiménez, Núria; Krüger, Martin

    2015-04-01

    Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperatures, with high pressure, etc.) were conducted using groundwater samples from three different locations. Series of microcosms (3 of each kind) containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides, frac fluids or flowback. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride could be used as substrates, while the effects of others like triethanolamine or light oil

  19. Intergalactic Star Formation

    NASA Astrophysics Data System (ADS)

    Boquien, Médéric

    2007-11-01

    The work presented here is about star formation in the unusual environment of collisional debris studied for the first time as such. These peculiar regions have an interstellar medium, and in particular a metallicity, similar to that of star forming regions in galactic discs while not undergoing similar environment effects such as density waves in the spiral arms for instance. This study has been conducted with a selection of exceptional systems that have ejected large quantities of gas into the intergalactic medium while also showing some intergalactic star forming regions. Principal Investigator as well as archive spectroscopy and imaging from multi-wavelength observations ranging from far ultraviolet to mid-infrared have been used. Withal a model has been built in order to reproduce the spectral energy distributions of intergalactic star forming regions and constrain the star formation histories, their extinctions and their fraction of stars coming from the parent galaxies' discs. Comparisons have been performed on the estimation of star formation rates between infrared, Halpha and ultraviolet wavelengths. This thesis has brought the following main new results: * some regions seem to be deprived of any old stellar population, and these are ideal laboratories in which to study star formation ; * the mid-infrared star formation rate estimator is as reliable as it is in spiral galaxies ; * the scatter in the estimation of star formation rates in various bands is similar to that of spiral galaxies and is mainly due to age effects ; * the combination of the extinction uncorrected Halpha line with mid-infrared yields a good estimation of the actual star formation rate ; * an important part of star formation, which can be as high as 85%, takes place in the intergalactic medium showing that in a young universe, in which this type of system is much more common than in the nearby universe, star formation from collisional debris can be an important factor of enrichment of

  20. Sparse Image Format

    2007-04-12

    The Sparse Image Format (SIF) is a file format for storing spare raster images. It works by breaking an image down into tiles. Space is savid by only storing non-uniform tiles, i.e. tiles with at least two different pixel values. If a tile is completely uniform, its common pixel value is stored instead of the complete tile raster. The software is a library in the C language used for manipulating files in SIF format. Itmore » supports large files (> 2GB) and is designed to build in Windows and Linux environments.« less

  1. Sparse Image Format

    SciTech Connect

    Eads, Damian Ryan

    2007-04-12

    The Sparse Image Format (SIF) is a file format for storing spare raster images. It works by breaking an image down into tiles. Space is savid by only storing non-uniform tiles, i.e. tiles with at least two different pixel values. If a tile is completely uniform, its common pixel value is stored instead of the complete tile raster. The software is a library in the C language used for manipulating files in SIF format. It supports large files (> 2GB) and is designed to build in Windows and Linux environments.

  2. Plant Formate Dehydrogenase

    SciTech Connect

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  3. Display formats manual

    NASA Technical Reports Server (NTRS)

    Runnels, R. L.

    1973-01-01

    The standards and procedures for the generation of operational display formats to be used in the Mission Control Center (MCC) display control system are presented. The required effort, forms, and fundamentals for the design, specifications, and production of display formats are identified. The principles of display design and system constraints controlling the creation of optimum operational displays for mission control are explained. The basic two types of MCC display systems for presenting information are described.

  4. Autonomous Formation Flight

    NASA Technical Reports Server (NTRS)

    Schkolnik, Gerard S.; Cobleigh, Brent

    2004-01-01

    NASA's Strategic Plan for the Aerospace Technology Enterprise includes ambitious objectives focused on affordable air travel, reduced emissions, and expanded aviation-system capacity. NASA Dryden Flight Research Center, in cooperation with NASA Ames Research Center, the Boeing Company, and the University of California, Los Angeles, has embarked on an autonomous-formation-flight project that promises to make significant strides towards these goals. For millions of years, birds have taken advantage of the aerodynamic benefit of flying in formation. The traditional "V" formation flown by many species of birds (including gulls, pelicans, and geese) enables each of the trailing birds to fly in the upwash flow field that exists just outboard of the bird immediately ahead in the formation. The result for each trailing bird is a decrease in induced drag and thus a reduction in the energy needed to maintain a given speed. Hence, for migratory birds, formation flight extends the range of the system of birds over the range of birds flying solo. The Autonomous Formation Flight (AFF) Project is seeking to extend this symbiotic relationship to aircraft.

  5. Heritability and reliability of automatically segmented human hippocampal formation subregions.

    PubMed

    Whelan, Christopher D; Hibar, Derrek P; van Velzen, Laura S; Zannas, Anthony S; Carrillo-Roa, Tania; McMahon, Katie; Prasad, Gautam; Kelly, Sinéad; Faskowitz, Joshua; deZubiracay, Greig; Iglesias, Juan E; van Erp, Theo G M; Frodl, Thomas; Martin, Nicholas G; Wright, Margaret J; Jahanshad, Neda; Schmaal, Lianne; Sämann, Philipp G; Thompson, Paul M

    2016-03-01

    The human hippocampal formation can be divided into a set of cytoarchitecturally and functionally distinct subregions, involved in different aspects of memory formation. Neuroanatomical disruptions within these subregions are associated with several debilitating brain disorders including Alzheimer's disease, major depression, schizophrenia, and bipolar disorder. Multi-center brain imaging consortia, such as the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) consortium, are interested in studying disease effects on these subregions, and in the genetic factors that affect them. For large-scale studies, automated extraction and subsequent genomic association studies of these hippocampal subregion measures may provide additional insight. Here, we evaluated the test-retest reliability and transplatform reliability (1.5T versus 3T) of the subregion segmentation module in the FreeSurfer software package using three independent cohorts of healthy adults, one young (Queensland Twins Imaging Study, N=39), another elderly (Alzheimer's Disease Neuroimaging Initiative, ADNI-2, N=163) and another mixed cohort of healthy and depressed participants (Max Planck Institute, MPIP, N=598). We also investigated agreement between the most recent version of this algorithm (v6.0) and an older version (v5.3), again using the ADNI-2 and MPIP cohorts in addition to a sample from the Netherlands Study for Depression and Anxiety (NESDA) (N=221). Finally, we estimated the heritability (h(2)) of the segmented subregion volumes using the full sample of young, healthy QTIM twins (N=728). Test-retest reliability was high for all twelve subregions in the 3T ADNI-2 sample (intraclass correlation coefficient (ICC)=0.70-0.97) and moderate-to-high in the 4T QTIM sample (ICC=0.5-0.89). Transplatform reliability was strong for eleven of the twelve subregions (ICC=0.66-0.96); however, the hippocampal fissure was not consistently reconstructed across 1.5T and 3T field strengths (ICC=0

  6. Heritability and reliability of automatically segmented human hippocampal formation subregions.

    PubMed

    Whelan, Christopher D; Hibar, Derrek P; van Velzen, Laura S; Zannas, Anthony S; Carrillo-Roa, Tania; McMahon, Katie; Prasad, Gautam; Kelly, Sinéad; Faskowitz, Joshua; deZubiracay, Greig; Iglesias, Juan E; van Erp, Theo G M; Frodl, Thomas; Martin, Nicholas G; Wright, Margaret J; Jahanshad, Neda; Schmaal, Lianne; Sämann, Philipp G; Thompson, Paul M

    2016-03-01

    The human hippocampal formation can be divided into a set of cytoarchitecturally and functionally distinct subregions, involved in different aspects of memory formation. Neuroanatomical disruptions within these subregions are associated with several debilitating brain disorders including Alzheimer's disease, major depression, schizophrenia, and bipolar disorder. Multi-center brain imaging consortia, such as the Enhancing Neuro Imaging Genetics through Meta-Analysis (ENIGMA) consortium, are interested in studying disease effects on these subregions, and in the genetic factors that affect them. For large-scale studies, automated extraction and subsequent genomic association studies of these hippocampal subregion measures may provide additional insight. Here, we evaluated the test-retest reliability and transplatform reliability (1.5T versus 3T) of the subregion segmentation module in the FreeSurfer software package using three independent cohorts of healthy adults, one young (Queensland Twins Imaging Study, N=39), another elderly (Alzheimer's Disease Neuroimaging Initiative, ADNI-2, N=163) and another mixed cohort of healthy and depressed participants (Max Planck Institute, MPIP, N=598). We also investigated agreement between the most recent version of this algorithm (v6.0) and an older version (v5.3), again using the ADNI-2 and MPIP cohorts in addition to a sample from the Netherlands Study for Depression and Anxiety (NESDA) (N=221). Finally, we estimated the heritability (h(2)) of the segmented subregion volumes using the full sample of young, healthy QTIM twins (N=728). Test-retest reliability was high for all twelve subregions in the 3T ADNI-2 sample (intraclass correlation coefficient (ICC)=0.70-0.97) and moderate-to-high in the 4T QTIM sample (ICC=0.5-0.89). Transplatform reliability was strong for eleven of the twelve subregions (ICC=0.66-0.96); however, the hippocampal fissure was not consistently reconstructed across 1.5T and 3T field strengths (ICC=0

  7. Positronium Formation in Muscle

    PubMed Central

    Gustafson, D. R.

    1970-01-01

    Positronium formation in muscle at +4°C and -4°C was examined by the measurement of the angular correlation of positron annihilation radiation. Since the positronium formation rate in ice is considerably higher than it is in water, there should be a comparable increase in the positronium formation rate in muscle tissue if recent speculation that cellular water is ordered in a semicrystalline icelike state is correct. Comparison of the angular correlation from muscle at +4°C with that from water at +4°C shows no enhancement of the positronium formation rate. Frozen muscle at -4°C shows an enhancement of the positronium formation rate of approximately half that found in ice at -4°C, indicating that most cellular water undergoes a normal water-ice transition when frozen. It is concluded therefore that cell water in muscle is not ordered in a hexagonal icelike structure. While the results are consistent with the hypothesis that cell water is in the liquid state, the hypothesis that cell water is ordered in an undetermined close packed structure which transforms to the hexagonal ice structure at or near 0°C cannot be ruled out. PMID:5436881

  8. Planet Formation and Habitability

    NASA Astrophysics Data System (ADS)

    alibert, yann

    2016-04-01

    Extrasolar planetary systems show an extreme diversity in mass and orbital architecture, and, very likely, in habitability. Explaining this diversity is one of the key challenges for theoretical models and requires understanding the formation, composition and evolution of planetary systems from the stage of the protoplanetary disk up to the full mature planetary system. I will review in this contribution the different models of planet formation and how they can be related to planetary habitability. In a first part, I will review the main planetary system formation models, and how, from these models, the composition of planets can be predicted. In a second part, I will link the results of these early phases of planetary systems, to the potential planetary habitability. Finally, I will show how it is possible, from transit observations, to put constraints on the water content of extrasolar planets.

  9. Gaussian entanglement of formation

    SciTech Connect

    Wolf, M.M.; Giedke, G.; Krueger, O.; Werner, R. F.; Cirac, J.I.

    2004-05-01

    We introduce a Gaussian version of the entanglement of formation adapted to bipartite Gaussian states by considering decompositions into pure Gaussian states only. We show that this quantity is an entanglement monotone under Gaussian operations and provide a simplified computation for states of arbitrary many modes. For the case of one mode per site the remaining variational problem can be solved analytically. If the considered state is in addition symmetric with respect to interchanging the two modes, we prove additivity of the considered entanglement measure. Moreover, in this case and considering only a single copy, our entanglement measure coincides with the true entanglement of formation.

  10. Isolating Triggered Star Formation

    SciTech Connect

    Barton, Elizabeth J.; Arnold, Jacob A.; Zentner, Andrew R.; Bullock, James S.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC

    2007-09-12

    Galaxy pairs provide a potentially powerful means of studying triggered star formation from galaxy interactions. We use a large cosmological N-body simulation coupled with a well-tested semi-analytic substructure model to demonstrate that the majority of galaxies in close pairs reside within cluster or group-size halos and therefore represent a biased population, poorly suited for direct comparison to 'field' galaxies. Thus, the frequent observation that some types of galaxies in pairs have redder colors than 'field' galaxies is primarily a selection effect. We use our simulations to devise a means to select galaxy pairs that are isolated in their dark matter halos with respect to other massive subhalos (N= 2 halos) and to select a control sample of isolated galaxies (N= 1 halos) for comparison. We then apply these selection criteria to a volume-limited subset of the 2dF Galaxy Redshift Survey with M{sub B,j} {le} -19 and obtain the first clean measure of the typical fraction of galaxies affected by triggered star formation and the average elevation in the star formation rate. We find that 24% (30.5 %) of these L* and sub-L* galaxies in isolated 50 (30) h{sup -1} kpc pairs exhibit star formation that is boosted by a factor of {approx}> 5 above their average past value, while only 10% of isolated galaxies in the control sample show this level of enhancement. Thus, 14% (20 %) of the galaxies in these close pairs show clear triggered star formation. Our orbit models suggest that 12% (16%) of 50 (30) h{sup -1} kpc close pairs that are isolated according to our definition have had a close ({le} 30 h{sup -1} kpc) pass within the last Gyr. Thus, the data are broadly consistent with a scenario in which most or all close passes of isolated pairs result in triggered star formation. The isolation criteria we develop provide a means to constrain star formation and feedback prescriptions in hydrodynamic simulations and a very general method of understanding the importance of

  11. Technobabble: File Formats.

    ERIC Educational Resources Information Center

    Wilson, Bradley

    1999-01-01

    Considers the confusion of over 20 different kinds of graphics programs. Briefly distinguishes between some of the more popular graphics formats (Photoshop, TIFF, JPEG, GIF, PICT, and EPS), and describes the benefits and disadvantages of each in the context of journalism education. (SC)

  12. Formation of planetesimals

    NASA Technical Reports Server (NTRS)

    Weidenschilling, Stuart J.

    1991-01-01

    Formation of planetesimals is discussed. The following subject areas are covered: (1) nebular structure; (2) aerodynamics of the solid bodies in the nebula; (3) problems with gravitational instability; (4) particle growth by coagulation; properties of fractal aggregates; and (5) coagulation and settling of fractal aggregates.

  13. Carrascolendas: A Formative Evaluation.

    ERIC Educational Resources Information Center

    Laosa, Luis M.

    A formative research project sought to test viewer reactions to two pilot programs of the Carrascolendas series. A total of 360 Puerto Rican-American, Cuban-American, Mexican-American, and Anglo-American children in grades 1, 2, and 3 were observed as they watched the programs. Results indicated that there was high eye contact during the…

  14. Formation of Freirian Facilitators.

    ERIC Educational Resources Information Center

    Noble, Phyllis

    This paper is written for people who are already familiar with the philosophy and methodology of Paulo Freire's liberatory education and are interested in creating a formation program for adult education facilitators using his ideas. The author describes the paper as "a collection of thoughts, of things to consider," when organizing such a…

  15. Formation in the Classroom

    ERIC Educational Resources Information Center

    Glennon, Fred; Jacobsen, Douglas; Jacobsen, Rhonda Hustedt; Thatamanil, John J.; Porterfield, Amanda; Moore, Mary Elizabeth

    2011-01-01

    What is the relationship between the academic knowledge of the guild and the formation of students in the classroom? This Forum gathers four essays originally presented at a Special Topics Session at the 2009 conference of the American Academy of Religion (Atlanta, Georgia), with a brief introductory essay by Fred Glennon explaining the genesis of…

  16. Concept Formation and Abstraction.

    ERIC Educational Resources Information Center

    Lunzer, Eric A.

    1979-01-01

    This paper examines the nature of concepts and conceptual processes and the manner of their formation. It argues that a process of successive abstraction and systematization is central to the evolution of conceptual structures. Classificatory processes are discussed and three levels of abstraction outlined. (Author/SJL)

  17. Common file formats.

    PubMed

    Leonard, Shonda A; Littlejohn, Timothy G; Baxevanis, Andreas D

    2007-01-01

    This appendix discusses a few of the file formats frequently encountered in bioinformatics. Specifically, it reviews the rules for generating FASTA files and provides guidance for interpreting NCBI descriptor lines, commonly found in FASTA files. In addition, it reviews the construction of GenBank, Phylip, MSF and Nexus files. PMID:18428774

  18. Kepler Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2015-01-01

    Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

  19. Generic file format

    NASA Astrophysics Data System (ADS)

    Felgate, Nick

    2002-11-01

    The Generic File Format (GFF) is a file format developed within the UK ASW community for the interchange and storage of underwater sonar data. Originally developed for the interchange of time-series data between analysis systems, it has been extended to provide for storage of processed acoustic data (e.g., power and DEMON spectrum, lofargram grey-scale), nonacoustic data (e.g., own-ship dynamics, sensor configuration) and event data (e.g., tracker output, sonar intercepts). The format employs the chunk concept, as used in the WAV and AIFF file formats, to provide extendability (including local variants) while providing a measure of backward compatability. However, the basic concept has been adapted to allow for the mixing in the one file of multiple channels of different sample-rates and data-types through the inclusion of a data frame concept and multiple data blocks. Chunk cross-referencing has been employed to ensure data consistency. A provision is made in the header of the file to store details of the sensor and processing for the data (e.g., the number of hydrophones, beam direction, FFT size) so that an analysis system does not need to know about the sensor or other system from which the data originated.

  20. The Formation of Trihalomethanes.

    ERIC Educational Resources Information Center

    Trussell, R. Rhodes; Umphres, Mark D.

    1978-01-01

    Reviewed are a number of factors important in the formation of trihalomethanes (THM) including the nature of aquatic humus and the influences of preozonation, bromide, pH, and chlorine. A brief investigation is also conducted into the kinetics of the THM reaction. Several major research needs are represented. (CS)

  1. Pattern formation today

    PubMed Central

    Chuong, Cheng-Ming; Richardson, Michael K.

    2010-01-01

    Patterns are orders embedded in randomness. They may appear as spatial arrangements or temporal series, and the elements may appear identical or with variations. Patterns exist in the physical world as well as in living systems. In the biological world, patterns can range from simple to complex, forming the basic building blocks of life. The process which generates this ordering in the biological world was termed pattern formation. Since Wolpert promoted this concept four decades ago, scientists from molecular biology, developmental biology, stem cell biology, tissue engineering, theoretical modeling and other disciplines have made remarkable progress towards understanding its mechanisms. It is time to review and re-integrate our understanding. Here, we explore the origin of pattern formation, how the genetic code is translated into biological form, and how complex phenotypes are selected over evolutionary time. We present four topics: Principles, Evolution, Development, and Stem Cells and Regeneration. We have interviewed several leaders in the field to gain insight into how their research and the field of pattern formation have shaped each other. We have learned that both molecular process and physico-chemical principles are important for biological pattern formation. New understanding will emerge through integration of the analytical approach of molecular-genetic manipulation and the systemic approach of model simulation. We regret that we could not include every major investigator in the field, but hope that this Special Issue of the Int. J. Dev. Biol. represents a sample of our knowledge of pattern formation today, which will help to stimulate more research on this fundamental process. PMID:19557673

  2. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 10 April 2002) The Science This THEMIS visible image was acquired near 7o S, 172o W (188o E) and shows a remarkable martian geologic deposit known as the Medusae Fossae Formation. This Formation, seen here as the raised plateau in the upper two-thirds of the image, is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region the deposit has been heavily eroded by the wind to produce a series of linear ridges called yardangs. These parallel ridges point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to sculpt the dry landscape of Mars. The Medusae Fossae Formation has been completely stripped from the surface in the lower third of the image, revealing a harder layer below that is more resistant to wind erosion. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Several ancient craters that were once completely buried by this deposit are being exposed, or exhumed, as the overlying Medusae Formation is removed. Very few impact craters are visible on this Formation, indicating that the surface seen today is relatively young, and that the processes of erosion are likely to be actively occurring. The Story Medusa of Greek mythology fame, the name-giver to this region, had snaky locks of hair that could turn a person to stone. Wild and unruly, this monster of the underworld could certainly wreak havoc on the world of the human imagination. As scary as she was, Medusa would have no advantage over the fierce, masterful winds blowing across Mars, which once carved the streaky, terrain at the top of this image. Wild and whipping, these winds have slowly eroded away the 'topsoil,' revealing ancient craters and other surface features they once covered. The loosely cemented particles of this 'topsoil' are likely made up of dust

  3. Cosmological structure formation

    NASA Technical Reports Server (NTRS)

    Schramm, David N.

    1991-01-01

    A summary of the current forefront problem of physical cosmology, the formation of structures (galaxies, clusters, great walls, etc.) in the universe is presented. Solutions require two key ingredients: (1) matter; and (2) seeds. Regarding the matter, it now seems clear that both baryonic and non-baryonic matter are required. Whether the non-baryonic matter is hot or cold depends on the choice of seeds. Regarding the seeds, both density fluctuations and topological defects are discussed. The combination of isotropy of the microwave background and the recent observations indicating more power on large scales have severly constrained, if not eliminated, Gaussian fluctuations with equal power on all scales, regardless of the eventual resolution of both the matter and seed questions. It is important to note that all current structure formation ideas require new physics beyond SU(3) x SU(2) x U(1).

  4. Emptiness Formation Probability

    NASA Astrophysics Data System (ADS)

    Crawford, Nicholas; Ng, Stephen; Starr, Shannon

    2016-08-01

    We present rigorous upper and lower bounds on the emptiness formation probability for the ground state of a spin-1/2 Heisenberg XXZ quantum spin system. For a d-dimensional system we find a rate of decay of the order {exp(-c L^{d+1})} where L is the sidelength of the box in which we ask for the emptiness formation event to occur. In the {d=1} case this confirms previous predictions made in the integrable systems community, though our bounds do not achieve the precision predicted by Bethe ansatz calculations. On the other hand, our bounds in the case {d ≥ 2} are new. The main tools we use are reflection positivity and a rigorous path integral expansion, which is a variation on those previously introduced by Toth, Aizenman-Nachtergaele and Ueltschi.

  5. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Petruzzo, Charles; Guzman, Jose

    2004-01-01

    This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include (1) targeting to a fixed tetrahedron location and orientation, and (2) rotating and translating the tetrahedron. The number of impulsive maneuvers can also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the NASA Goddard Magnetospheric Multi-Scale (MMS) mission to compute preliminary formation control fuel requirements.

  6. Prominence Formation Processes

    NASA Astrophysics Data System (ADS)

    Welsch, B. T.; DeVore, C. R.; Antiochos, S. K.

    2005-01-01

    Martens and Zwaan (ApJ v. 558 872) have proposed a prominence/ filament formation model in which differential rotation drives reconnection between two initially unconnected active regions to form helical field lines that support mass and are held down by overlying field. Using an MHD solver with adaptive refinement we simulated this process by imposing a shear flow meant to mimic differential rotation on two bipolar flux distributions meant to mimic distinct active regions. In some runs the flux systems are initially potential while in others they have been twisted by footpoint rotation to inject helicity prior to imposing the shear flow. The resulting structures are studied to understand the role of helicity in the formation of prominence-like structures.

  7. Formation of bacterial nanocells

    NASA Astrophysics Data System (ADS)

    Vainshtein, Mikhail; Kudryashova, Ekaterina; Suzina, Natalia; Ariskina, Elena; Voronkov, Vadim

    1998-07-01

    Existence of nanobacteria received increasing attention both in environmental microbiology/geomicro-biology and in medical microbiology. In order to study a production of nanoforms by typical bacterial cells. Effects of different physical factors were investigated. Treatment of bacterial cultures with microwave radiation, or culturing in field of electric current resulted in formation a few types of nanocells. The number and type of nanoforms were determined with type and dose of the treatment. The produced nanoforms were: i) globules, ii) clusters of the globules--probably produced by liaison, iii) nanocells coated with membrane. The viability of the globules is an object opened for doubts. The nanocells discovered multiplication and growth on solidified nutrient media. The authors suggest that formation of nanocells is a common response of bacteria to stress-actions produced by different agents.

  8. Galaxy Formation and Evolution

    NASA Astrophysics Data System (ADS)

    Nagamine, Kentaro; Reddy, Naveen; Daddi, Emanuele; Sargent, Mark T.

    2016-07-01

    In this chapter, we discuss the current status of observational and computational studies on galaxy formation and evolution. In particular, a joint analysis of star-formation rates (SFRs), stellar masses, and metallicities of galaxies throughout cosmic time can shed light on the processes by which galaxies build up their stellar mass and enrich the environment with heavy elements. Comparison of such observations and the results of numerical simulations can give us insights on the physical importance of various feedback effects by supernovae and active galactic nuclei. In Sect. 1, we first discuss the primary methods used to deduce the SFRs, stellar masses, and (primarily) gas-phase metallicities in high-redshift galaxies. Then, we show how these quantities are related to each other and evolve with time. In Sect. 2, we further examine the distribution of SFRs in galaxies following the `Main Sequence' paradigm. We show how the so-called `starbursts' display higher specific SFRs and SF efficiencies by an order of magnitude. We use this to devise a simple description of the evolution of the star-forming galaxy population since z ˜3 that can successfully reproduce some of the observed statistics in the infrared (IR) wavelength. We also discuss the properties of molecular gas. In Sect. 3, we highlight some of the recent studies of high-redshift galaxy formation using cosmological hydrodynamic simulations. We discuss the physical properties of simulated galaxies such as luminosity function and escape fraction of ionizing photons, which are important statistics for reionization of the Universe. In particular the escape fraction of ionizing photons has large uncertainties, and studying gamma-ray bursts (which is the main topic of this conference) can also set observational constraints on this uncertain physical parameter as well as cosmic star formation rate density.

  9. Simulations of antihydrogen formation

    SciTech Connect

    Robicheaux, F.

    2004-08-01

    The results of simulations of antihydrogen formation in a Penning trap are reported. The antihydrogen atoms are formed by three-body capture. We find that the arrested nature of the three-body capture in the trap greatly reduces the expected binding energy of the antihydrogen. Typically, the formed antihydrogen has larger velocity along the magnetic field than across the field and a binding energy below k{sub B}T.

  10. Formate-assisted pyrolysis

    DOEpatents

    DeSisto, William Joseph; Wheeler, Marshall Clayton; van Heiningen, Adriaan R. P.

    2015-03-17

    The present invention provides, among other thing, methods for creating significantly deoxygenated bio-oils form biomass including the steps of providing a feedstock, associating the feedstock with an alkali formate to form a treated feedstock, dewatering the treated feedstock, heating the dewatered treated feedstock to form a vapor product, and condensing the vapor product to form a pyrolysis oil, wherein the pyrolysis oil contains less than 30% oxygen by weight.

  11. Mesospheric cloud formations

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1980-01-01

    Formation of mesospheric clouds as a result of deposition of large amounts of H2O by the heavy lift launch vehicle (HLLV) of the solar power satellite system is discussed. The conditions which must be met in order to form and maintain clouds near the mesopause are described. The frequency and magnitude of H2O injections from the HLLV rocket exhaust are considered.

  12. Hail Formation in Florida

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    Hail poses a substantial threat to life and property in the state of Florida. These losses could be minimized through better understanding of the relationships between atmospheric variables that impact hail formation in Florida. Improving hail forecasting in Florida requires analyzing a number of meteorological parameters and synoptic data related to hail formation. NOAA archive data was retrieved to create a database that was used to categorize text files of hail days. The text files were entered into the National Oceanic and Atmospheric Administration Earth System Research Laboratory website to create National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis maps of atmospheric variables for Florida hail days as well as days leading to the hail event. These data were then analyzed to determine the relationship between variables that affect hail formation, in general, across different regions and seasons in Florida using Statistical Product and Service Solutions. The reasoning for the differing factors affecting hail formation between regions, seasons and hail sizes were discussed, as well as forecasting suggestions relating to region and month in Florida. The study found that the majority of all hail that occurs in Florida is during the wet season. A low Lifted Index, high Precipitable Water and lower than average Sea Level Pressure, in most cases, is present during hail days in Florida. Furthermore, results show that Vector Wind magnitude increases as hail size increases. Additionally, several atmospheric variables useful to studying hail events, such as Lifted Index, Precipitable Water, Sea Level Pressure, Vector Wind and Temperature have significant correlations with each other depending on the region and season being observed. Strong correlations between low Lifted Index, high Precipitable Water values and the occurrence of hail events are discussed, as well as the relationship between temperature anomalies at various

  13. Tetrahedron Formation Control

    NASA Technical Reports Server (NTRS)

    Guzman, Jose J.

    2003-01-01

    Spacecraft flying in tetrahedron formations are excellent instrument platforms for electromagnetic and plasma studies. A minimum of four spacecraft - to establish a volume - is required to study some of the key regions of a planetary magnetic field. The usefulness of the measurements recorded is strongly affected by the tetrahedron orbital evolution. This paper considers the preliminary development of a general optimization procedure for tetrahedron formation control. The maneuvers are assumed to be impulsive and a multi-stage optimization method is employed. The stages include targeting to a fixed tetrahedron orientation, rotating and translating the tetrahedron and/or varying the initial and final times. The number of impulsive maneuvers citn also be varied. As the impulse locations and times change, new arcs are computed using a differential corrections scheme that varies the impulse magnitudes and directions. The result is a continuous trajectory with velocity discontinuities. The velocity discontinuities are then used to formulate the cost function. Direct optimization techniques are employed. The procedure is applied to the Magnetospheric Multiscale Mission (MMS) to compute preliminary formation control fuel requirements.

  14. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  15. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  16. Mars brine formation experiment

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey M.; Bullock, Mark A.; Stoker, Carol R.

    1993-09-01

    Evaporites, particularly carbonates, nitrates, and sulfates, may be major sinks of volatiles scavenged from the martian atmosphere. Mars is thought to have once had a denser, warmer atmosphere that permitted the presence of liquid surface water. The conversion of atmospheric CO2 into carbonate is hypothesized to have degraded the martian climate to its present state of a generally subfreezing, desiccated desert. The rate for such a conversion under martian conditions is poorly known, so the time scale of climate degradation by this process cannot be easily evaluated. If some models are correct, carbonate formation may have been fast at geological time scales. The experiments of Booth and Kieffer also imply fast (106 - 107 yr) removal of the missing CO2 inventory, estimated to be 1 - 5 bar, by means of carbonate formation. The timing of formation of many of the fluvial features observed on Mars is, in large part, dependent on when and how fast the atmosphere changed. A knowledge of the rate at which carbonates and nitrates formed is also essential for assessing the probability that life, or its chemical precursors, could have developed on Mars. No previous experiments have quantitatively evaluated the rate of solution for a suite of mobile anions and cations from unaltered minerals and atmospheric gases into liquid water under Mars-like conditions. Such experiments are the focus of this task.

  17. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  18. Model of kimberlite formation

    NASA Astrophysics Data System (ADS)

    Kostrovitsky, Sergey; Fiveyskaya, Lyudmila

    2013-04-01

    The critical goals in recognizing the nature of kimberlites are to find out: (1) the primary composition of melt of these rocks and (2) the principal processes of evolution of primary composition of kimberlites while ascending from mantle depth towards earth surface. Suppose, that the primary composition of kimberlite melt-fluid was in fact the composition of asthenosphere melt geochemically being close to alkaline-basalt (Hi-µ) saturated with high CO2. The genetic relation of kimberlites with basaltoids is indicated by a spatial and temporal affinity of their formation (Carlson et al, 2006; Lehmann et al, 2010; Tappe et al, 2012), similarity of the pattern of incompatible elements distribution, presence of megacryst minerals in alkaline basaltoids, Pyr-Alm garnet included, and finally, model calculation of parent melt composition for low-Cr megacryst minerals; it showed this composition to be typical for the alkaline basaltoid (Jones, 1980). At the asthenosphere level there was differentiation of basaltoid melt-fluid which was responsible for formation of its different parts with varying melt to fluid ratio and possibly varying content of alkalis (K2O). The outbreak of asthenosphere substance through lithosphere mantle proceeded by different scenarios: (a) With a noticeable dominance of fluid component kimberlites were formed by the capture and contamination of high-Mg, high-Cr rocks of lithosphere mantle that caused formation of high-Mg kimberlites. That corresponds to model of Russell (2012). (b) With a considerable proportion of melt phase depending on saturation in fluid there formed magnesium-ferriferous and ferriferous-titaniferous petrochemical types of kimberlites. There is no doubt that in formation of these kimberlite types the contamination of lithosphere material was the case, at the much lower level than in formation of high-Mg kimberlites. This model logically explains steady differences of petrochemistry of kimberlites making up clusters of

  19. Formation of giant planets

    NASA Astrophysics Data System (ADS)

    Magni, G.; Coradini, A.

    2003-04-01

    In this presentation we address the problem of the formation of giant planets and their regular satellites. We study in particular the problem of formation of the Jupiter System comparing the results of the model with the present characteristics of the system, in order to identify what are those better represented by our approach. In fact here, using a 3-D hydro-dynamical code, we study the modalities of gas accretion onto a solid core, believed to be the seed from which Jupiter started. To do that we have modelled three main regions: the central planet, a turbulent accretion disk surrounding it and an extended region from which the gas is collected. In the extended region we treat the gas as a frictionless fluid. Our main goal is to identify what are the characteristics of the planet during its growth and the physical parameters affecting its growth at the expenses of the nebular gas present in the feeding zone. Moreover we want to understand what are the thermodynamical parameters characterizing the gas captured by the planet and swirling around it. Finally, we check if a disk can be formed in prograde rotation around the planet and if this disk can survive the final phases of the planet formation. Due to the interaction between the accreting planet and the disk it has been necessary to develop a complete model of the Jupiter’s structure. In fact the radiation emitted by the growing planet heats up the surrounding gas. In turn the planet’s thermodynamic structure depend on the mass accretion rate onto it. When the accretion is rapid, shock waves in the gas are formed close to the planet. This region cannot be safely treated by a numerical code; for this reason we have developed a semi-analytically model of a a turbulent accretion disk to be considered as transition between the planet and the surrounding disk.

  20. What initiated planetesimal formation?

    NASA Technical Reports Server (NTRS)

    Cuzzi, J. N.; Dobrovolskis, A. R.; Hogan, R. C.

    1994-01-01

    The physical structure of primitive (chondritic) meteorites, even after some geological processing and modification, is thought by most to contain clues as to the first stage of accretion of solid matter into objects that might be called planetesimals. However, theoretical understanding of the processes responsible for this important stage is shaky. We note what we believe are fundamental obstacles for the Goldreich-Ward version of rapid and direct planetesimal formation via gravitational instability in a settled particle layer, and describe an alternative scenario which might lead from grainy nebula gas to primitive planetesimals in a way that has intriguing connections to the meteorite evidence.

  1. Modeling river delta formation.

    PubMed

    Seybold, Hansjörg; Andrade, José S; Herrmann, Hans J

    2007-10-23

    A model to simulate the time evolution of river delta formation process is presented. It is based on the continuity equation for water and sediment flow and a phenomenological sedimentation/erosion law. Different delta types are reproduced by using different parameters and erosion rules. The structures of the calculated patterns are analyzed in space and time and compared with real data patterns. Furthermore, our model is capable of simulating the rich dynamics related to the switching of the mouth of the river delta. The simulation results are then compared with geological records for the Mississippi River. PMID:17940031

  2. Ultrarelativistic black hole formation.

    PubMed

    East, William E; Pretorius, Frans

    2013-03-01

    We study the head-on collision of fluid particles well within the kinetic energy dominated regime (γ = 8 to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The gravitational radiation reaches luminosities of 0.014 c(5)/G, carrying 16 ± 2% of the total energy.

  3. Adiabatic Halo Formation

    SciTech Connect

    Bazzani, A.; Turchetti, G.; Benedetti, C.; Rambaldi, S.; Servizi, G.

    2005-06-08

    In a high intensity circular accelerator the synchrotron dynamics introduces a slow modulation in the betatronic tune due to the space-charge tune depression. When the transverse motion is non-linear due to the presence of multipolar effects, resonance islands move in the phase space and change their amplitude. This effect introduces the trapping and detrapping phenomenon and a slow diffusion in the phase space. We apply the neo-adiabatic theory to describe this diffusion mechanism that can contribute to halo formation.

  4. Flexible formation configuration for terrain following flight: Formation keeping constraints

    NASA Astrophysics Data System (ADS)

    Latyshev, Simon

    This work suggests a control method for the terrain-following formation motion of a group of communicating autonomous agents. The presented approach centers on defining a suitable set of constraints for formation keeping task that shall be fulfilled while agents are negotiating an unknown terrain toward the predefined goal location. It allows agents to maintain a general geometric formation shape, while allowing each individual formation member freedom of maneuver, required for terrain collision free motion. Formation structure is defined with the use of virtual leader. Formation keeping constraints are defined with plane surfaces, specified relative to position and navigation vector of the virtual leader. Formation navigation and guidance constraints are defined using navigation vectors of formation members and the virtual leader. Alternative designs for the constraints derived with parabolic, cone, and cylindrical surfaces are considered. Formation control is derived using the Udwadia-Kalaba equation, following corresponding approach to the development of control methods for constraint based dynamical systems, including leader-follower systems defined using geometric constraints. Approach to terrain following motion requiring agents to stay within bounds of cylindrical corridor volumes built around their respective navigation vectors is assumed. Individual formation primitives and multi-level, hierarchical, formation structures are considered. Simulations, based on three degrees of freedom nonlinear model of an agent, performed using Mathematica and specifically developed combined Maya-Mathematica modeling and simulation system, demonstrate that a flexible terrain following formation motion is achieved with the presented sets of constraints.

  5. Star Formation in Irregular Galaxies.

    ERIC Educational Resources Information Center

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  6. Standard exercise report format (SERF)

    SciTech Connect

    1995-12-31

    This talk summarizes the reasons for the development of draft SERF the Standard Exercise Report Format used for reporting the results of emergency preparedness exercises, and gives a summary of the format and rational behind it.

  7. Formats for Presenting Procedural Instruction

    ERIC Educational Resources Information Center

    Blaiwes, Arthur S.

    1974-01-01

    Thirty male college students performed a mock communication controller's task under three different instructional formats, short sentences, logical tree, and coding. It was concluded that format variations mainly influence the more difficult tasks. (Author/DE)

  8. Tooth formation - delayed or absent

    MedlinePlus

    Delayed or absent tooth formation; Teeth - delayed or absent formation ... The age at which a tooth comes in varies. Most infants get their first tooth between 6 and 9 months, but it may be earlier or later. ...

  9. Fullerene formation and annealing

    SciTech Connect

    Mintmire, J.W.

    1996-04-05

    Why does the highly symmetric carbon cluster C{sub 60} form in such profusion under the right conditions? This question was first asked in 1985, when Kroto suggested that the predominance of the C{sub 60} carbon clusters observed in the molecular beam experiments could be explained by the truncated icosahedral (or soccer ball) form. The name given to this cluster, buckminsterfullerene, led to the use of the term fullerenes for the family of hollow-cage carbon clusters made up of even numbers of triply coordinated carbons arranged with 12 pentagonal rings and an almost arbitrary number of hexagonal rings. More than a decade later, we still lack a completely satisfying understanding of the fundamental chemistry that takes place during fullerene formation. Most current models for fullerene formation require a facile mechanism for ring rearrangement in the fullerene structure, but the simplest proposed mechanisms are believed to have unrealistically high activation barriers. In recent research calculations have suggested that atomic carbon in the reaction mixture could act as a catalyst and allow substantially lower activation barriers for fullerene annealing. This article discusses the background for this research and other adjunct research. 14 refs.

  10. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1994-01-01

    Two KC-135 flight campaigns have been conducted to date which are specifically dedicated to study bubble formation in microgravity. The first flight was conducted during March 14-18, 1994, and the other during June 20-24, 1994. The results from the June 1994 flight have not been analyzed yet, while the results from the March flight have been partially analyzed. In the first flight three different experiments were performed, one with the specific aim at determining whether or not cavitation can take place during any of the fluid handling procedures adopted in the shuttle bioprocessing experiments. The other experiments were concerned with duplicating some of the procedures that resulted in bubble formation, namely the NCS filling procedure and the needle scratch of a solid surface. The results from this set of experiments suggest that cavitation did not take place during any of the fluid handling procedures. The results clearly indicate that almost all were generated as a result of the breakup of the gas/liquid interface. This was convincingly demonstrated in the scratch tests as well as in the liquid fill tests.

  11. Method for measuring pollutant formation

    NASA Technical Reports Server (NTRS)

    Annen, Kurt (Inventor); Stickler, David B. (Inventor)

    2001-01-01

    Diagnostic methods for determining an instantaneous rate of pollutant formation in a combustion system are based on measurement of chemiluminescence intensity generated simultaneously with the formation of the pollutant. The chemiluminescent signal is generated by an analog reaction which occurs in parallel with a key step in the formation of a specific pollutant of interest. The connection between the analog reaction and the pollution reaction is such that the chemiluminescent signal indicates the local, instantaneous formation rate of the pollutant of interest.

  12. Formative Assessment: Simply, No Additives

    ERIC Educational Resources Information Center

    Roskos, Kathleen; Neuman, Susan B.

    2012-01-01

    Among the types of assessment the closest to daily reading instruction is formative assessment. In contrast to summative assessment, which occurs after instruction, formative assessment involves forming judgments frequently in the flow of instruction. Key features of formative assessment include identifying gaps between where students are and…

  13. Fracture system influence on the reservoirs rock formation of Ordovician-Devonian carbonates in West Siberia tectonic depression

    NASA Astrophysics Data System (ADS)

    Koveshnikov, A. E.; Nesterova, A. C.; Dolgaya, T. F.

    2016-09-01

    During the Paleozoic period from the beginning of the Cambrian to the end of the Carboniferous in the boundaries of the West Siberia tectonic depression there occurred the sea, where the carbonate platforms were formed by the limestones accumulation. All the area at the end of the Carboniferous period was turned to land. Resulting from Gertsynskaya folding in the times of Permian - Triassic the formed deposits were folded and denudated to a considerable extent. Besides, the reservoir rocks of the crust of weathering including redeposited one, were formed as a result of hypergenesis, during the continental stand of the area in the near-surface zone. A new geological prospecting unit has been suggested which underlies these crusts of weathering and formed during fracture tectonic processes with hydrothermal-metasomatic limestones reworking and the processes of hydrothermal leaching and dolomitization. So, in the carbonate platforms the system of fissure zones related to tectonic disturbance was formed. This has a dendrite profile where the series of tangential, more thinned fractures deviate from the stem and finish in pores and caverns. The carbonate platforms formation in the West Siberia tectonic depression has been analyzed, their dynamics and gradual increasing from the minimal in Ordovician and Silurian to maximal at the end of the Late Devonian has been shown.

  14. PEX13 deficiency in mouse brain as a model of Zellweger syndrome: abnormal cerebellum formation, reactive gliosis and oxidative stress

    PubMed Central

    Müller, C. Catharina; Nguyen, Tam H.; Ahlemeyer, Barbara; Meshram, Mallika; Santrampurwala, Nishreen; Cao, Siyu; Sharp, Peter; Fietz, Pamela B.; Baumgart-Vogt, Eveline; Crane, Denis I.

    2011-01-01

    SUMMARY Delayed cerebellar development is a hallmark of Zellweger syndrome (ZS), a severe neonatal neurodegenerative disorder. ZS is caused by mutations in PEX genes, such as PEX13, which encodes a protein required for import of proteins into the peroxisome. The molecular basis of ZS pathogenesis is not known. We have created a conditional mouse mutant with brain-restricted deficiency of PEX13 that exhibits cerebellar morphological defects. PEX13 brain mutants survive into the postnatal period, with the majority dying by 35 days, and with survival inversely related to litter size and weaning body weight. The impact on peroxisomal metabolism in the mutant brain is mixed: plasmalogen content is reduced, but very-long-chain fatty acids are normal. PEX13 brain mutants exhibit defects in reflex and motor development that correlate with impaired cerebellar fissure and cortical layer formation, granule cell migration and Purkinje cell layer development. Astrogliosis and microgliosis are prominent features of the mutant cerebellum. At the molecular level, cultured cerebellar neurons from E19 PEX13-null mice exhibit elevated levels of reactive oxygen species and mitochondrial superoxide dismutase-2 (MnSOD), and show enhanced apoptosis together with mitochondrial dysfunction. PEX13 brain mutants show increased levels of MnSOD in cerebellum. Our findings suggest that PEX13 deficiency leads to mitochondria-mediated oxidative stress, neuronal cell death and impairment of cerebellar development. Thus, PEX13-deficient mice provide a valuable animal model for investigating the molecular basis and treatment of ZS cerebellar pathology. PMID:20959636

  15. Statins and bone formation.

    PubMed

    Garrett, I R; Gutierrez, G; Mundy, G R

    2001-05-01

    The main therapy needed most in the bone field is an anabolic agent for the treatment of osteoporosis. Current drugs on the market, which included bisphosphonates, calcitonin, estrogen and related compounds, vitamin D analogues trabecular microarchitecture. Therefore, it would be desirable to have a satisfactory and universally and iprifalvone, are essentially bone resorption inhibitors that mainly act to stabilize bone mass. Patients with established osteoporosis have lost more than 50% of their bone mass at critical sites in the skeleton, and more over have marked disruption of acceptable drug that would stimulate new bone formation and correct this disturbance of trabecular microarchitecture characteristic of established osteoporosis. Recently inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, which controls the first step in the biosynthesis of cholesterol, have been shown to stimulate bone formation in rodents both in vitro and in vivo. The effect is associated with an increased expression of the bone morphogenetic protein-2 (BMP-2) gene in bone cells. These statins drugs are widely used agents for lowering cholesterol and reducing heart attacks, however they are also known to elicit numerous pleiotropic effects including inhibition of proliferation and migration of smooth muscle cells, inhibition of tumor growth and anti-inflammatory activity. Some of these effects have been attributed to not only to the reduction of cholesterol synthesis by inhibition of the HMG-CoA reductase enzyme but also by the concurrent reduction in downstream metabolites of the mevalonate pathway such as mevalonate, farnesyl pyrophosphate and geranylgeranyl pyrophosphate. The findings that statins are capable of increasing bone formation and bone mass in rodents suggests a potential new action for the statins, which may be beneficial in patients with established osteoporosis where marked bone loss has occurred. Recent clinical data suggests that they

  16. Physics of amniote formation.

    PubMed

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally.

  17. Physics of amniote formation.

    PubMed

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally. PMID:27627351

  18. Mechanism of GEMS formation

    SciTech Connect

    Bradley, J P; Dai, Z R

    2004-03-10

    GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) were examined using 200 keV analytical transmission electron microscopy. The morphologies and crystallography of embedded relict grains reveal that GEMS are pseudomorphs formed by irradiation processing of crystals free-floating in space. Some GEMS retain a compositional and morphological ''memory'' of the crystal from which they formed. Pseudomorphism rules out condensation, annealing, flash heating, or shock melting as alternative mechanisms of GEMS formation. A significant and often dominant fraction of the atoms in GEMS were sputtered deposited from other grains. Therefore, a normal (solar) isotopic composition is not a reliable indicator of whether GEMS formed in the solar system or in presolar interstellar or circumstellar environments.

  19. Transitions in biofilm formation

    NASA Astrophysics Data System (ADS)

    Gordon, Vernita; Thatcher, Travis; Cooley, Benjamin

    2011-03-01

    Biofilms are multicellular, dynamic communities formed by interacting unicellular organisms bound to a surface. Forming a biofilm is a developmental process, characterized by sequential changes in gene expression and behavior as bacteria and yeast progress from discrete, free-swimming cells though stages that arrive at a mature biofilm. We are developing automated metrics to identify key transitions in early biofilm formation as cells attach to a surface, populate that surface, and adhere to each other to form early microcolonies. Our metrics use high-throughput tracking and analysis of microscopy movies to localize these transitions in space and time. Each of these transitions is associated with a loss of entropy in the bacterial system and, therefore, with biological activity that drives this loss of entropy. Better understanding of these transitions will allow automated determination of the strength and turn-on of attractive cell-surface and cell-cell interactions as biofilm development progresses.

  20. DUST FORMATION IN MACRONOVAE

    SciTech Connect

    Takami, Hajime; Ioka, Kunihito; Nozawa, Takaya E-mail: kunihito.ioka@kek.jp

    2014-07-01

    We examine dust formation in macronovae (as known as kilonovae), which are the bright ejecta of neutron star binary mergers and one of the leading sites of r-process nucleosynthesis. In light of information about the first macronova candidate associated with GRB 130603B, we find that dust grains of r-process elements have difficulty forming because of the low number density of the r-process atoms, while carbon or elements lighter than iron can condense into dust if they are abundant. Dust grains absorb emission from ejecta with an opacity even greater than that of the r-process elements, and re-emit photons at infrared wavelengths. Such dust emission can potentially account for macronovae without r-process nucleosynthesis as an alternative model. This dust scenario predicts a spectrum with fewer features than the r-process model and day-scale optical-to-ultraviolet emission.

  1. Group Formation in Economics

    NASA Astrophysics Data System (ADS)

    Demange, Gabrielle; Wooders, Myrna

    2005-01-01

    Broad and diverse ranges of activities are conducted within and by organized groups of individuals, including political, economic and social activities. These activities have recently become a subject of intense interest in economics and game theory. Some of the topics investigated in this collection are models of networks of power and privilege, trade networks, co-authorship networks, buyer-seller networks with differentiated products, and networks of medical innovation and the adaptation of new information. Other topics are social norms on punctuality, clubs and the provision of club goods and public goods, research and development and collusive alliances among corporations, and international alliances and trading agreements. While relatively recent, the literature on game theoretic studies of group formation in economics is already vast. This volume provides an introduction to this important literature on game-theoretic treatments of situations with networks, clubs, and coalitions, including some applications.

  2. Physics of amniote formation

    NASA Astrophysics Data System (ADS)

    Fleury, Vincent; Murukutla, Ameya Vaishnavi; Chevalier, Nicolas R.; Gallois, Benjamin; Capellazzi-Resta, Marina; Picquet, Pierre; Peaucelle, Alexis

    2016-08-01

    We present a detailed study of the formation of the amniotic sac in the avian embryo, and a comparison with the crocodile amniotic sac. We show that the amniotic sac forms at a circular line of stiffness contrast, separating rings of cell domains. Cells align at this boundary, and this in turn orients and concentrates the tension forces. The tissue fold which forms the amniotic sac is locked exactly along this line due to the colocalization of the stiffness contrast and of the tensile force. In addition, the tensile force plays a regenerative role when the amniotic sac is cut. The fold forming the ventral side of the embryo displays the same characteristics. This work shows that amniote embryogenesis consists of a cascade of buckling events taking place at the boundaries between regions of differing mechanical properties. Hence, amniote embryogenesis relies on a simple and robust biomechanical scheme used repeatedly, and selected ancestrally.

  3. Biofilm formation by enterococci.

    PubMed

    Mohamed, Jamal A; Huang, David B

    2007-12-01

    Enterococci are an important global cause of nosocomial infections, being increasingly associated with urinary tract infections, endocarditis, intra-abdominal and pelvic infections, catheter-related infections, surgical wound infections, and central nervous system infections. The two most common enterococci species are Enterococcus faecalis and Enterococcus faecium. Both are capable of producing biofilms, which consist of a population of cells attached irreversibly on various biotic and abiotic surfaces, encased in a hydrated matrix of exopolymeric substances. Many environmental and genetic factors are associated or have been proposed to be associated with the production of biofilm. This review discusses recent advances in knowledge about the biology and genetics of biofilm formation and the role of biofilms in enterococci pathogenesis.

  4. Recipes for planet formation

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    2009-11-01

    Anyone who has ever used baking soda instead of baking powder when trying to make a cake knows a simple truth: ingredients matter. The same is true for planet formation. Planets are made from the materials that coalesce in a rotating disk around young stars - essentially the "leftovers" from when the stars themselves formed through the gravitational collapse of rotating clouds of gas and dust. The planet-making disk should therefore initially have the same gas-to-dust ratio as the interstellar medium: about 100 to 1, by mass. Similarly, it seems logical that the elemental composition of the disk should match that of the star, reflecting the initial conditions at that particular spot in the galaxy.

  5. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today

  6. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 16 April 2002) The Science This THEMIS visible image was acquired near 11o N, 159o W (201o E) and shows examples of the remarkable variations that can be seen in the erosion of the Medusae Fossae Formation. This Formation is a soft, easily eroded deposit that extends for nearly 1,000 km along the equator of Mars. In this region, like many others throughout the Medusae Fossae Formation, the surface has been eroded by the wind into a series of linear ridges called yardangs. These ridges generally point in direction of the prevailing winds that carved them, and demonstrate the power of martian winds to erode the landscape of Mars. The easily eroded nature of the Medusae Fossae Formation suggests that it is composed of weakly cemented particles, and was most likely formed by the deposition of wind-blown dust or volcanic ash. Within this single image it is possible to see differing amounts of erosion and stripping of layers in the Medusae Fossae Formation. Near the bottom (southern) edge of the image a rock layer with a relatively smooth upper surface covers much of the image. Moving upwards (north) in the image this layer becomes more and more eroded. At first there are isolated regions where the smooth unit has been eroded to produce sets of parallel ridges and knobs. Further north these linear knobs increase in number, and only small, isolated patches of the smooth upper surface remain. Finally, at the top of the image, even the ridges have been removed, exposing the remarkably smooth top of hard, resistant layer below. This sequence of layers with differing hardness and resistance to erosion is common on Earth and on Mars, and suggests significant variations in the physical properties, composition, particle size, and/or cementation of these martian layers. As is common throughout the Medusae Fossae Formation, very few impact craters are visible, indicating that the surface exposed is relatively young, and that the process of erosion may be active today

  7. Gas formation. Formation temperatures of thermogenic and biogenic methane.

    PubMed

    Stolper, D A; Lawson, M; Davis, C L; Ferreira, A A; Santos Neto, E V; Ellis, G S; Lewan, M D; Martini, A M; Tang, Y; Schoell, M; Sessions, A L; Eiler, J M

    2014-06-27

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models. PMID:24970083

  8. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment.

  9. Nuclear ``pasta'' formation

    NASA Astrophysics Data System (ADS)

    Schneider, A. S.; Horowitz, C. J.; Hughto, J.; Berry, D. K.

    2013-12-01

    The formation of complex nonuniform phases of nuclear matter, known as nuclear pasta, is studied with molecular dynamics (MD) simulations containing 51200 nucleons. A phenomenological nuclear interaction is used that reproduces the saturation binding energy and density of nuclear matter. Systems are prepared at an initial density of 0.10fm-3 and then the density is decreased by expanding the simulation volume at different rates to densities of 0.01fm-3 or less. An originally uniform system of nuclear matter is observed to form spherical bubbles (“swiss cheese”), hollow tubes, flat plates (“lasagna”), thin rods (“spaghetti”) and, finally, nearly spherical nuclei with decreasing density. We explicitly observe nucleation mechanisms, with decreasing density, for these different pasta phase transitions. Topological quantities known as Minkowski functionals are obtained to characterize the pasta shapes. Different pasta shapes are observed depending on the expansion rate. This indicates nonequilibrium effects. We use this to determine the best ways to obtain lower energy states of the pasta system from MD simulations and to place constraints on the equilibration time of the system.

  10. Bubble formation in microgravity

    NASA Technical Reports Server (NTRS)

    Antar, Basil N.

    1996-01-01

    An extensive experimental program was initiated for the purpose of understanding the mechanisms leading to bubble generation during fluid handling procedures in a microgravity environment. Several key fluid handling procedures typical for PCG experiments were identified for analysis in that program. Experiments were designed to specifically understand how such procedures can lead to bubble formation. The experiments were then conducted aboard the NASA KC-135 aircraft which is capable of simulating a low gravity environment by executing a parabolic flight attitude. However, such a flight attitude can only provide a low gravity environment of approximately 10-2go for a maximum period of 30 seconds. Thus all of the tests conducted for these experiments were designed to last no longer than 20 seconds. Several experiments were designed to simulate some of the more relevant fluid handling procedures during protein crystal growth experiments. These include submerged liquid jet cavitation, filling of a cubical vessel, submerged surface scratch, attached drop growth, liquid jet impingement, and geysering experiments. To date, four separate KC-135 flight campaigns were undertaken specifically for performing these experiments. However, different experiments were performed on different flights.

  11. Formation of "bound

    NASA Astrophysics Data System (ADS)

    Nowak, K.; Kästner, M.; Miltner, A.

    2009-04-01

    During degradation of organic pollutants in soil, metabolites, microbial biomass, CO2and "bound" residues ("non-extractable" residues in soil organic matter) are formed. Enhanced transformation of these contaminants into "bound" residues has been proposed as an alternative remediation method for polluted soils. However, this kind of residues may pose a potential risk for the environment due to their chemical structure and possible remobilization under different conditions. Therefore particular attention is given actually to "bound" residues. Part of these non-extractable residues may be "biogenic," because microorganisms use the carbon from the pollutant to form their biomass components (fatty acids, amino acids, amino sugars), which subsequently may be incorporated into soil organic matter. Furthermore, the CO2 originating from mineralization of xenobiotics, can be re-assimilated by microorganisms and also incorporated into "biogenic residue". The hazard posed by "bound" residues may be overestimated because they are "biogenic" (contain microbial fatty acids and amino acids). The knowledge about the pathways of "biogenic residue" formation is necessary for a proper assessment of the fate of tested pollutants and their turnover in the soil environment. Moreover, these data are needed to establish the realistic degradation rates of the contaminants in soil. The main objectives of this study are: to quantify the extent of "biogenic residue" (fatty acids, amino acids, amino sugars) formation during the degradation of a model pollutant (2,4-dichlorophenoxyacetic acid = 2,4-D) and during CO2 assimilation by microorganisms and to evaluate which components are mainly incorporated into "bound" residues. To investigate the extent of "biogenic residue" formation in soil during the degradation of 2,4-D, experiments with either 14C-U-ring and 13C6-2,4-D or carboxyl-14C 2,4-D were performed. The incubation experiments were performed according to OECD test guideline 307, in the

  12. Prominence formation and oscillations

    NASA Astrophysics Data System (ADS)

    Chen, P. F.

    Prominences, or filaments, are a striking phenomenon in the solar atmosphere. Besides their own rich features and dynamics, they are related to many other activities, such as solar flares and coronal mass ejections (CMEs). In the past several years we have been investigating the prominence formation, oscillations, and eruptions through both data analysis and radiative hydrodynamic and magnetohydrodynamic (MHD) simulations. This paper reviews our progress on these topics, which includes: (1) With updated radiative cooling function, the coronal condensation becomes a little faster than previous work; (2) Once a seed condensation is formed, it can grow via siphon flow spontaneously even if the evaporation stops; (3) A scaling law was obtained to relate the length of the prominence thread to various parameters, indicating that higher prominences tend to have shorter threads, which is consistent with the fact that threads are long in active region prominences and short in quiescent prominences; (4) It was proposed that long-time prominence oscillations out of phase might serve as a precursor for prominence eruptions and CMEs; (5) An ensemble of oscillating prominence threads may explain the counter-streaming motion.

  13. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment. PMID:20069645

  14. Bead lightning formation

    SciTech Connect

    Ludwig, G.O.; Saba, M.M.F.

    2005-09-15

    Formation of beaded structures in triggered lightning discharges is considered in the framework of both magnetohydrodynamic (MHD) and hydrodynamic instabilities. It is shown that the space periodicity of the structures can be explained in terms of the kink and sausage type instabilities in a cylindrical discharge with anomalous viscosity. In particular, the fast growth rate of the hydrodynamic Rayleigh-Taylor instability, which is driven by the backflow of air into the channel of the decaying return stroke, dominates the initial evolution of perturbations during the decay of the return current. This instability is responsible for a significant enhancement of the anomalous viscosity above the classical level. Eventually, the damping introduced at the current channel edge by the high level of anomalous viscous stresses defines the final length scale of bead lightning. Later, during the continuing current stage of the lightning flash, the MHD pinch instability persists, although with a much smaller growth rate that can be enhanced in a M-component event. The combined effect of these instabilities may explain various aspects of bead lightning.

  15. The formation of dew

    NASA Astrophysics Data System (ADS)

    Beysens, D.

    Dew is the condensation into liquid droplets of water vapor on a substrate. The presence of a substrate is the origin of the peculiarities and richness of the phenomenon. We review the aspects related to heterogeneous nucleation and subsequent growth of water droplets. A key point is the drop interaction through drop fusion or coalescence, which leads to scaling in the growth and gives universality to the process. The effects of substrate heterogeneity and gravity effects are also considered. Coalescence events lead to temporal and spatio-temporal fluctuations in the substrate coverage, drop configuration, etc., which give rise to a very peculiar dynamics. When the substrate is a liquid or a liquid crystal, the drop pattern can exhibit special spatial orders, such as crystalline, hexatic phases and fractal contours. And condensation on a solid substrate near its melting point can make the drop jump. The applications of monitoring dew formation are manyfold. Examples can be found in nanoelectronics and optics (vapor deposition and thin films), medicine (sterilization process), agriculture (green houses). We here discuss in greater details the production of clean water by "atmospheric wells".

  16. Large Format Radiographic Imaging

    SciTech Connect

    J. S. Rohrer; Lacey Stewart; M. D. Wilke; N. S. King; S. A Baker; Wilfred Lewis

    1999-08-01

    Radiographic imaging continues to be a key diagnostic in many areas at Los Alamos National Laboratory (LANL). Radiographic recording systems have taken on many form, from high repetition-rate, gated systems to film recording and storage phosphors. Some systems are designed for synchronization to an accelerator while others may be single shot or may record a frame sequence in a dynamic radiography experiment. While film recording remains a reliable standby in the radiographic community, there is growing interest in investigating electronic recording for many applications. The advantages of real time access to remote data acquisition are highly attractive. Cooled CCD camera systems are capable of providing greater sensitivity with improved signal-to-noise ratio. This paper begins with a review of performance characteristics of the Bechtel Nevada large format imaging system, a gated system capable of viewing scintillators up to 300 mm in diameter. We then examine configuration alternatives in lens coupled and fiber optically coupled electro-optical recording systems. Areas of investigation include tradeoffs between fiber optic and lens coupling, methods of image magnification, and spectral matching from scintillator to CCD camera. Key performance features discussed include field of view, resolution, sensitivity, dynamic range, and system noise characteristics.

  17. Beach-cusp formation

    USGS Publications Warehouse

    Sallenger, A.H., Jr.

    1979-01-01

    Field experiments on beach-cusp formation were undertaken to document how the cuspate form develops and to test the edge-wave hypothesis on the uniform spacing of cusps. These involved observations of cusps forming from an initially plane foreshore. The cuspate form was observed to be a product of swash modification of an intertidal beach ridge as follows. A ridge, cut by a series of channels quasi-equally spaced along its length, was deposited onto the lower foreshore. The ridge migrated shoreward with flood tide, while the longshore positions of the channels remained fixed. On ebb tide, changes in swash circulation over the ridge allowed the upwash to flow shoreward through the channels and the channel mouths were eroded progressively wider until adjacent mouths met, effecting a cuspate shape. Measured spacings of cusps, ranging in size from less than 1 m to more than 12 m, agree well with computed spacings due to either zero-mode subharmonic or zero-mode synchronous edge waves. Edge-wave-induced longshore variations in run up will cause water ponded behind a ridge to converge at points of low swash and flow seaward as relatively narrow currents eroding channels spaced at one edge-wave wavelength for synchronous edge waves or one half wavelength for subharmonic edge waves. The channels are subsequently modified into cusp troughs as described above.

  18. The KEA image file format

    NASA Astrophysics Data System (ADS)

    Bunting, Peter; Gillingham, Sam

    2013-08-01

    There are a large number of image formats already in use within the remote sensing community but currently there is no format that provides the features of: compression, support for large file sizes, ground control points, raster attribute tables and inbuilt image pyramids. Therefore, a new image format, named KEA, after the New Zealand bird, has been proposed. The KEA format provides a full implementation of the GDAL data model and is implemented within a HDF5 file. A software library with a GDAL driver have been freely provided to the community allowing use through any GDAL based software. The new format has comparable performance with existing formats while producing smaller file sizes and is already within active use for a number of projects within Landcare Research, New Zealand, and the wider community.

  19. Gaining Insight into Star Formation: Resolved Star Formation Laws

    NASA Astrophysics Data System (ADS)

    Liebst, Kelley; Scowen, Paul A.

    2014-06-01

    Until recently astronomers have used star formation laws to measure the star formation rate and star formation efficiency of galaxies only on global scales because of the poor resolution of available data. What I am now capable of producing is a spatially resolved star formation law that can provide direct insight into the physical processes that govern star formation and assess the short-term nature of bursts of star formation and the longer-term nature of larger-scale events that can dictate the global distribution of stars and the ultimate fate of a galaxy as a whole. I am using exquisite narrowband optical data from a variety of sources, including the Hubble Space Telescope, and Kitt Peak National Observatory, etc., in conjunction with infrared data from the Spitzer Infrared Nearby Galaxy Survey and the Spitzer Local Volume Legacy survey, neutral gas data from The HI Nearby Galaxy Survey, and molecular gas data from the Berkeley-Illinois-Maryland Association Survey of Nearby Galaxies, to provide star formation rates and star formation efficiencies on previously inaccessible small spatial scales across a suite of galaxies that represent a range of star formation environments and scales. My sample includes 18 spiral galaxies ranging from 2.1 to 15.1 Mpc in distance and offers a large range of morphological types (i.e. a large range of star formation environments). I am using these data to test different models of star formation modes under a variety of physical conditions and relate the variations I observe to the known local physical conditions and the associated star formation histories for each locale within each galaxy.This is the heart of the matter - that the nature and evolution of the local physical environment intimately influences how stars can form, how quickly and how massive those stars are allowed to form, and as a result how they shape the local conditions for subsequent star formation. It is this tracking of the stellar ecology that is vital for

  20. BACTERIOPHAGE FORMATION WITHOUT BACTERIAL GROWTH

    PubMed Central

    Price, Winston H.

    1947-01-01

    1. Iodoacetate, fluoride, and azide have been found to prevent the formation of phage and to inhibit the synthesis of ATP by Staphylococcus muscae. It is suggested that energy-rich phosphate is needed for the synthesis of phage. 2. Gramicidin prevented the formation of phage. 3. No differences were found between normal bacteria and phage-infected bacteria in the inorganic phosphate, adenosinetriphosphate, ribonucleic acid, and desoxyribonucleic acid content of the cells. 4. The mechanism of phage formation is discussed. PMID:18896936

  1. Binary stars - Formation by fragmentation

    NASA Technical Reports Server (NTRS)

    Boss, Alan P.

    1988-01-01

    Theories of binary star formation by capture, separate nuclei, fission and fragmentation are compared, assessing the success of theoretical attempts to explain the observed properties of main-sequence binary stars. The theory of formation by fragmentation is examined, discussing the prospects for checking the theory against observations of binary premain-sequence stars. It is concluded that formation by fragmentation is successful at explaining many of the key properties of main-sequence binary stars.

  2. Medusae Fossae Formation

    NASA Technical Reports Server (NTRS)

    1998-01-01

    An exotic terrain of wind-eroded ridges and residual smooth surfaces are seen in one of the highest resolution images ever taken of Mars from orbit. The Medusae Fossae formation is believed to be formed of the fragmental ejecta of huge explosive volcanic eruptions. When subjected to intense wind-blasting over hundreds of millions of years, this material erodes easily once the uppermost tougher crust is breached. In the Mars Orbiter Camera (MOC) image shown on the right, the crust, or cap rock, can be seen in the upper right part of the picture. The finely-spaced ridges are similar to features on Earth called yardangs, which are formed by intense winds plucking individual grains from, and by wind-driven sand blasting particles off, sedimentary deposits.

    The MOC image was taken on October 30, 1997 at 11:05 AM PST, shortly after the Mars Global Surveyor spacecraft's 31st closest approach to Mars. The image covers an area 3.6 X 21.5 km (2.2 X 13.4 miles) at 3.6 m (12 feet) per picture element--craters only 11 m (36 feet, about the size of a swimming pool) across can be seen. The context image (left; the best Viking view of the area; VO 1 387S34) has a resolution of 240 m/pixel, or 67 times lower resolution than the MOC frame.

    Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  3. ANTIBODY FORMATION IN VITRO

    PubMed Central

    Fishman, M.

    1961-01-01

    Neutralizing activity against T2 bacteriophage appeared in cultures of lymph node cells from normal rats in response to their in vitro stimulation with a cell-free filtrate derived from homogenized rat macrophages which had been incubated with T2 bacteriophage. This activity was specifically directed against T2 bacteriophage. It resided in a fraction of the culture fluid which had the salting-out properties of serum globulin. Phage neutralization was inhibited by antibody specific for rat serum gamma globulin. Antibody production against T2 bacteriophage in cultures of lymph node cells from normal animals failed to occur if (a) T2 bacteriophage alone was added, (b) if the incubation period of macrophages and T2 phage was unduly shortened, (c) if the cell-free filtrate was heated at 80–100°C for 15 minutes, (d) if more than an optimal amount of T2 bacteriophage was added to the macrophages. Additional factors which prevented the formation of antibody were the heat inactivation of the lymph node cells or the addition to the culture medium of either streptomycin or ribonuclease. Finally, it was found that macrophages and lymph node cells had to be obtained from animals of one and the same species. All essential findings on the production of antibody to T2 bacteriophage in vitro could be confirmed by substitution of the chick embryo for the tissue culture medium. The results are discussed in terms of a possible mechanism of antibody production in which an RNAse-sensitive substance resulting from the interaction of macrophages and antigen is capable of stimulating antibody synthesis in lymphocytic cells. PMID:13893304

  4. Plasmapause formation at Saturn

    NASA Astrophysics Data System (ADS)

    Thomsen, M. F.; Mitchell, D. G.; Jia, X.; Jackman, C. M.; Hospodarsky, G.; Coates, A. J.

    2015-04-01

    Cassini observations during a rapid, high-latitude, dawnside pass from Saturn's lobe to inner magnetosphere on 25 June 2009 provide strong evidence for the formation of a "plasmapause" at Saturn by Vasyliunas-type nightside reconnection of previously mass-loaded flux tubes. A population of hot, tenuous plasma that lies between the lobe and the dense inner magnetospheric plasma is consistent with a region formed by very recent injection from a reconnection region in the tail, including low density, high temperature, supercorotational flow, a significant O+ content, and the near-simultaneous observation of enhanced Saturn kilometric radiation emissions. The sharp boundary between that region and the cool dense inner magnetospheric plasma thus separates flux tubes that were involved in the reconnection from those that successfully traversed the nightside without mass loss. This event demonstrates that tail reconnection can strip off inner magnetospheric plasma in to at least dipole L = 8.6. Clear evidence of flux tube interchange driven by the sharp boundary is found, both inward moving flux tubes of hotter plasma and, for the first time, the outward moving cool population. The outward moving cool regions have azimuthal sizes less than 1 RS, were probably created within the past 1.2 h, and have outflow speeds greater than about 5 km/s. At the outer edge of the reconnected region, there is also a possible signature of Dungey-type lobe reconnection following the initial Vasyliunas-type reconnection. Observations from this event are entirely consistent with previously described global MHD simulations of tail reconnection, plasmoid departure, and Saturnward injection of reconnected flux.

  5. Planet formation and searches

    NASA Astrophysics Data System (ADS)

    Montgomery, Ryan Michael

    2009-08-01

    This thesis explores the possibilities for discovery of terrestrial-mass planets in the habitable zones of their host stars. Towards this aim, we present the results of three projects and discuss another two preliminary studies of further explorations. In so doing, we explore a fairly comprehensive range of possibilities regarding the formation and detection of terrestrial- mass planets in the habitable zone. We first study the potential for terrestrial planets to form in situ in and around the habitable zones of M-dwarf stars. We proceed to explore the feasibility of searches for these planets using the transit method via Monte- Carlo simulations. We find that M-dwarfs pose an interesting challenge for study: being inherently dim, widely spread on the sky, and photometrically variable. We present results of simulated ground-based transit search campaigns as well as simulated searches from a modest satellite mission. Our second project is a straightforward extension of the previous study: a collaborative effort to search for transit signals around the nearest M-dwarf: Proxima Centauri. We describe our observations as well as the Monte-Carlo analysis used to place constraints on the possible planetary radii and periods. Our third project is a search for transiting extra-solar Jovian planets using the Rossiter-McLaughlin effect. We search through the private Keck radial- velocity datasets for undiscovered Rossiter-McLaughlin signals. We present our results in the form of both strong null-result datasets as well as potential transiting systems. We then briefly analyze these larger Jovian planets for potential to harbor potentially habitable terrestrial satellites. Our final preliminary analysis looks into the potential for the Large Synoptic Survey Telescope to detect transiting Neptune-mass planets orbiting M-dwarfs which could then lead to terrestrial-mass planet detections. The sum of these efforts is a comprehensive investigation into the likelihood and

  6. Formative Assessment Probes: Is It a Rock? Continuous Formative Assessment

    ERIC Educational Resources Information Center

    Keeley, Page

    2013-01-01

    A lesson plan is provided for a formative assessment probe entitled "Is It a Rock?" This probe is designed for teaching elementary school students about rocks through the use of a formative assessment classroom technique (FACT) known as the group Frayer Model. FACT activates students' thinking about a concept and can be used to…

  7. The Formation of Galactic Bulges

    NASA Astrophysics Data System (ADS)

    Carollo, C. Marcella; Ferguson, Henry C.; Wyse, Rosemary F. G.

    2000-03-01

    Part I. Introduction: What are galactic bulges?; Part II. The Epoch of Bulge Formation: Origin of bulges; Deep sub-mm surveys: High-z ULIRGs and the formation of spheroids; Ages and metallicities for stars in the galactic bulge; Integrated stellar populations of bulges: First results; HST-NICMOS observations of galactic bulges: Ages and dust; Inside-out bulge formation and the origin of the Hubble sequence; Part III. The Timescales of Bulge Formation: Constraints on the bulge formation timescale from stellar populations; Bulge building with mergers and winds; Role of winds, starbursts, and activity in bulge formation; Dynamical timescales of bulge formation; Part IV. Physical Processes in Bulge Formation: the role of bars for secular bulge formation; Bars and boxy/peanut-shaped bulges: an observational point of view; Boxy- and peanut-shaped bulges; A new class of bulges; The role of secondary bars in bulge formation; Radial transport of molecular gas to the nuclei of spiral galaxies; Dynamical evolution of bulge shapes; Two-component stellar systems: Phase-space constraints; Central NGC 2146 - a firehose-type bending instability?; Bulge formation: the role of the multi-phase ISM; Global evolution of a self-gravitating multi-phase ISM in the central kpc region of galaxies; Part V. Bulge Phenomenology: Bulge-disk decomposition of spiral galaxies in the near-infrared; The triaxial bulge of NGC 1371; The bulge-disk orthogonal decoupling in galaxies: NGC 4698 and NGC 4672; The kinematics and the origin of the ionized gas in NGC 4036; Optically thin thermal plasma in the galactic bulge; X-ray properties of bulges; The host galaxies of radio-loud AGN; The centers of radio-loud early-type galaxies with HST; Central UV spikes in two galactic spheroids; Conference summary: where do we stand?

  8. Lichen-rock interaction in volcanic environments: evidences of soil-precursor formation

    NASA Astrophysics Data System (ADS)

    Vingiani, S.; Adamo, P.; Terribile, F.

    2012-04-01

    The weathering action of the lichens Lecidea fuscoatra (L.) Ach. and Stereocaulon vesuvianum Pers. on basaltic rock collected on the slopes of Mt. Etna (Sicily) at 1550 m a.s.l. has been studied using optical (OM) and electron (SEM) microscopy equipped with microanalytical device (EDS). Biological factors associated with lichen growth play a major role in the weathering of minerals on bare rocks and contribute to the preliminary phases of soil formation. The present work investigates the biogeophysical and biogeochemical weathering associated to the growth of epilithic lichens on lava flows from Mt. Etna (Sicily) and Mt. Vesuvius (Campania). The chosen lichen species were the crustose Lecidea fuscoatra (L.) Ach., the foliose Xanthoparmelia conspersa and the fructicose Stereocaulon vesuvianum Pers. An integrated approach based on the study of both disturbed and undisturbed samples of lichenized rock was applied in order to appreciate the complexity of the rock-lichen interface environment in terms of micromorphological, mineralogical and chemical properties. XRD and XRF analyses coupled to microscopical (OM), submicroscopical (SEM) and microanalitical (EDS) observations were the used techniques. In both study environments, the chemical, mineralogical and micromorphological properties of the uncoherent materials found at the lichen-rock interface suggest they consist of rock fragments eroded from the surroundings and accumulated in cavities and fissures of the rough lava flows. According to the thallus morphology, the lichens colonizing the lava preserve the interface materials from further aeolic and water erosion, provide these materials of organic matter and moisture, entrap allochtonous quartz and clay minerals. The calcium oxalate production by L. fuscoatra and X. conspersa, the Al enrichment around S. vesuvianum hyphae and the occurrence of Fe-oxide phases at the rock-lichen interface are evidences of lichens interaction with the underlying sediments. Indeed

  9. The formation of Pangea

    NASA Astrophysics Data System (ADS)

    Stampfli, G. M.; Hochard, C.; Vérard, C.; Wilhem, C.; vonRaumer, J.

    2013-05-01

    The making of Pangea is the result of large-scale amalgamation of continents and micro-continents, which started at the end of the Neoproterozoic with the formation of Gondwana. As pieces were added to Gondwana on its South-American, Antarctica and Australia side, ribbon-like micro-continents were detached from its African and South-Chinese side: Cadomia in the late Neoproterozoic, Avalonia and Hunia in the Ordovician, Galatia in the Devonian and Cimmeria in the Permian. Cadomia was re-accreted to Gondwana, but the other ribbon-continents were accreted to Baltica, North-China, Laurussia or Laurasia. Finding the origin of these numerous terranes is a major geological challenge. Recently, a global plate tectonic model was developed together with a large geological/geodynamic database, at the Lausanne University, covering the last 600 Ma of the Earth's history. Special attention was given to the placing of Gondwana derived terranes in their original position, using all possible constraints. We propose here a solution for the Variscan terranes, another paper deals with the Altaids. The Galatian super-terrane was detached from Gondwana in the Devonian, during the opening of Paleotethys, and was quickly separated into four sub-terranes that started to by-pass each other. The leading terranes collided at the end of the Devonian with the Hanseatic terrane detached from Laurussia. In the Carboniferous, Gondwana started to impinge onto the amalgamated terranes, creating the Variscan chain and the Pangean super-continent. East of Spain Paleotethys remained opened until the Triassic, subducting northward under Laurasia. Roll-back of the Paleotethyan slab triggered the collapse of most of the European Variscan orogen, which was replaced by series of Permian rifts, some of them becoming oceanized back-arc basins during the Triassic. Major force changes at the Pangean plate limits at the end of the Triassic provoked its break-up, through the opening of the proto

  10. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As ...

  11. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying it. Formats can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). As w...

  12. Portable File Format (PFF) specifications.

    SciTech Connect

    Dolan, Daniel H.,

    2015-02-01

    Created at Sandia National Laboratories, the Portable File Format (PFF) allows binary data transfer across computer platforms. Although this capability is supported by many other formats, PFF files are still in use at Sandia, particularly in pulsed power research. This report provides detailed PFF specifications for accessing data without relying on legacy code.

  13. Bibliography Formatting Software: An Update.

    ERIC Educational Resources Information Center

    Stigleman, Sue

    1993-01-01

    Discusses software used for formatting bibliographies and describes 52 programs. Information provided includes type of operating system required, publication formats, citation styles, ability to arrange by subject, use of downloaded references, network versions, costs, and plans for future changes. A directory of the programs and producers is…

  14. Formation Algorithms and Simulation Testbed

    NASA Technical Reports Server (NTRS)

    Wette, Matthew; Sohl, Garett; Scharf, Daniel; Benowitz, Edward

    2004-01-01

    Formation flying for spacecraft is a rapidly developing field that will enable a new era of space science. For one of its missions, the Terrestrial Planet Finder (TPF) project has selected a formation flying interferometer design to detect earth-like planets orbiting distant stars. In order to advance technology needed for the TPF formation flying interferometer, the TPF project has been developing a distributed real-time testbed to demonstrate end-to-end operation of formation flying with TPF-like functionality and precision. This is the Formation Algorithms and Simulation Testbed (FAST) . This FAST was conceived to bring out issues in timing, data fusion, inter-spacecraft communication, inter-spacecraft sensing and system-wide formation robustness. In this paper we describe the FAST and show results from a two-spacecraft formation scenario. The two-spacecraft simulation is the first time that precision end-to-end formation flying operation has been demonstrated in a distributed real-time simulation environment.

  15. The Apennine Bench Formation revisited

    NASA Technical Reports Server (NTRS)

    Spudis, P. D.; Hawke, B. R.

    1985-01-01

    The Apennine Bench Formation consists of pre-mare light plains materials that crop out south of the crater Archimedes, inside the Imbrium basin. This material was ascribed to either impact or volcanic origins. The characteristics of Apollo 15 KREEP basalts and the Apennine Bench Formation are reviewed to determine whether their characteristics are compatible with a volcanic origin.

  16. Star formation in the multiverse

    SciTech Connect

    Bousso, Raphael; Leichenauer, Stefan

    2009-03-15

    We develop a simple semianalytic model of the star formation rate as a function of time. We estimate the star formation rate for a wide range of values of the cosmological constant, spatial curvature, and primordial density contrast. Our model can predict such parameters in the multiverse, if the underlying theory landscape and the cosmological measure are known.

  17. Tariffs Formation on oil transportation

    NASA Astrophysics Data System (ADS)

    Glyzina, T. S.; Kolbysheva, Yu. V.; Grivtsova, I. S.; Dmitrieva, N. V.

    2016-09-01

    Oil transportation via trunk pipelines is an important part of the oil industry's activity. The main instrument of tariff regulation is the method of tariffs formation. Three methods of tariffs formation such as the method of economically justified costs (the Cost plus method), the method of economically justified return on investment capital (the RAB method), and the method of tariffs indexation were considered.

  18. Formative Assessment: A Critical Review

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot

    2011-01-01

    This paper covers six interrelated issues in formative assessment (aka, "assessment for learning"). The issues concern the definition of formative assessment, the claims commonly made for its effectiveness, the limited attention given to domain considerations in its conceptualisation, the under-representation of measurement principles in that…

  19. Sibling similarity in family formation.

    PubMed

    Raab, Marcel; Fasang, Anette Eva; Karhula, Aleksi; Erola, Jani

    2014-12-01

    Sibling studies have been widely used to analyze the impact of family background on socioeconomic and, to a lesser extent, demographic outcomes. We contribute to this literature with a novel research design that combines sibling comparisons and sequence analysis to analyze longitudinal family-formation trajectories of siblings and unrelated persons. This allows us to scrutinize in a more rigorous way whether sibling similarity exists in family-formation trajectories and whether siblings' shared background characteristics, such as parental education and early childhood family structure, can account for similarity in family formation. We use Finnish register data from 1987 through 2007 to construct longitudinal family-formation trajectories in young adulthood for siblings and unrelated dyads (N = 14,257 dyads). Findings show that family formation is moderately but significantly more similar for siblings than for unrelated dyads, also after controlling for crucial parental background characteristics. Shared parental background characteristics add surprisingly little to account for sibling similarity in family formation. Instead, gender and the respondents' own education are more decisive forces in the stratification of family formation. Yet, family internal dynamics seem to reinforce this stratification such that siblings have a higher probability to experience similar family-formation patterns. In particular, patterns that correspond with economic disadvantage are concentrated within families. This is in line with a growing body of research highlighting the importance of family structure in the reproduction of social inequality.

  20. Cyanide Formation by Chromobacterium violaceum

    PubMed Central

    Michaels, Ruth; Corpe, W. A.

    1965-01-01

    Michaels, Ruth (Columbia University, New York, N.Y.), and W. A. Corpe. Cyanide formation by Chromobacterium violaceum. J. Bacteriol. 89:106–112. 1965.—The formation of cyanide by a Chromobacterium violaceum strain was studied with growing cultures and with nonproliferating cells grown in complex and chemically defined media. Most of the cyanide was produced during the log-phase growth of the organism, and accumulated in the culture supernatant fluid. A synergistic effect of glycine and methionine on cyanide formation in a chemically defined medium was observed, and the amount of cyanide formed was found to be dependent on the concentrations of the two substances. Cyanide formation by nonproliferating cells was stimulated by preincubation with glycine and methionine. Cyanide formation by adapted cells in the presence of glycine and methionine was stimulated by succinate, malate, or fumarate, and depressed by azide and 2,4-dinitrophenol. Methionine could be replaced by betaine, dimethylglycine, and choline. PMID:14255648

  1. Physics of primordial star formation

    NASA Astrophysics Data System (ADS)

    Yoshida, Naoki

    2012-09-01

    The study of primordial star formation has a history of nearly sixty years. It is generally thought that primordial stars are one of the key elements in a broad range of topics in astronomy and cosmology, from Galactic chemical evolution to the formation of super-massive blackholes. We review recent progress in the theory of primordial star formation. The standard theory of cosmic structure formation posits that the present-day rich structure of the Universe developed through gravitational amplification of tiny matter density fluctuations left over from the Big Bang. It has become possible to study primordial star formation rigorously within the framework of the standard cosmological model. We first lay out the key physical processes in a primordial gas. Then, we introduce recent developments in computer simulations. Finally, we discuss prospects for future observations of the first generation of stars.

  2. Dissipative processes in galaxy formation.

    PubMed Central

    Silk, J

    1993-01-01

    A galaxy commences its life in a diffuse gas cloud that evolves into a predominantly stellar aggregation. Considerable dissipation of gravitational binding energy occurs during this transition. I review here the dissipative processes that determine the critical scales of luminous galaxies and the generation of their morphology. The universal scaling relations for spirals and ellipticals are shown to be sensitive to the history of star formation. Semiphenomenological expressions are given for star-formation rates in protogalaxies and in starbursts. Implications are described for elliptical galaxy formation and for the evolution of disk galaxies. PMID:11607396

  3. Antihydrogen Formation using Cold Plasmas

    SciTech Connect

    Madsen, N.; Bowe, P.D.; Hangst, J.S.; Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A.; Amsler, C.; Johnson, I.; Pruys, H.; Regenfus, C.; Bonomi, G.; Bouchta, A.; Doser, M.; Kellerbauer, A.; Landua, R.; Cesar, C.L.; Charlton, M.; Joergensen, L.V.

    2004-10-20

    Antihydrogen, the antimatter counterpart of the hydrogen atom, can be formed by mixing cold samples of antiprotons and positrons. In 2002 the ATHENA collaboration succeeded in the first production of cold antihydrogen. By observing and imaging the annihilation products of the neutral, non-confined, antihydrogen atoms annihilating on the walls of the trap we can observe the production in quasi-real-time and study the dynamics of the formation mechanism. The formation mechanism strongly influences the final state of the formed antihydrogen atoms, important for future spectroscopic comparison with hydrogen. This paper briefly summarizes the current understanding of the antihydrogen formation in ATHENA.

  4. Dynamics of rock varnish formation

    SciTech Connect

    Raymond, R. Jr.; Reneau, S.L.; Guthrie, G.D. Jr.; Bish, D.L.; Harrington, C.D.

    1991-01-01

    Our studies of rock varnish from the southwestern United States suggest that the Mn-phase in rock varnish has neither the chemistry nor the crystal structure of birnessite. Rather, the Mn-rich phase is non-crystalline and contains Ba, Ca, Fe, Al, and P. Unknowns concerning the formation of this non-crystalline Mn phase must be resolved before researchers are able to define chemical parameters of rock varnish formation based upon conditions of formation of the Mn phase. 6 refs., 9 figs.

  5. Formate dehydrogenase from Pseudomonas oxalaticus.

    PubMed

    Müller, U; Willnow, P; Ruschig, U; Höpner, T

    1978-02-01

    Formate dehydrogenase (EC 1.2.1.2) from Pseudomonas oxalaticus has been isolated and characterized. The enzyme (molecular weight 315000) is a complex flavoprotein containing 2 FMN, 18--25 non-heme iron atoms and 15--20 acid-labile sulphides. In the last step of the purification, a sucrose gradient centrifugation, a second catalytically active species has been found apparently originating from a dissociation of the enzyme into two equal subunits. The enzyme is specific toward its natural substrate formate. It transfers electrons to NAD+, oxygen, ferricyanide, and a lot of nonphysiological acceptors (dyes). In addition electrons are transferred from NADH to these acceptors. The (reversible) removal of FMN requires a reduction step. Reincorporation has been followed by the reappearance of the reactivity against formate and by fluorescence titration. The deflavo enzyme also binds FAD and riboflavin. The resulting enzyme species show characteristic catalytic abilities. Activity against formate is peculiar to the FMN species. PMID:631130

  6. Results of Aluminosilicate Formation Testing

    SciTech Connect

    Wilmarth, W.R.

    2001-09-11

    The purpose of this work was to examine several experimental parameters of the formation of aluminosilicates under several tank chemistries, examine the conversion of crystalline phases, and determine inherent solubilities of certain crystal phases.

  7. Ultraviolet Mars Reveals Cloud Formation

    NASA Video Gallery

    Images from MAVEN's Imaging UltraViolet Spectrograph were used to make this movie of rapid cloud formation on Mars on July 9-10, 2016. The ultraviolet colors of the planet have been rendered in fal...

  8. Star Formation Across Galactic Environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

    2013-01-01

    I present here parallel investigations of star formation in AGN-free and quasar host galaxies. These environments are both insightful; quasars are among the most violent objects known, reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to dwarf star-forming galaxies. The AGN-free galaxies are drawn from the KPNO International Spectroscopic Survey, an Hα-selected, volume-limited survey was designed to avoid continuum luminosity bias. This work studies the KISS galaxies in mid- and far-IR using Spitzer IRAC and MIPS photometry. These IR bands are interesting because the UV light from young stars is reprocessed into thermal emission in the far-IR (24μm MIPS) by dust and into vibrational transition features in the mid-IR (8.0μm IRAC) by polycyclic aromatic hydrocarbons (PAHs). This work examines the efficiencies of PAH and dust emission as tracers of star-formation. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has no systematic dependance on galactic mass. My study of quasar host galaxies utilizes images of eight PG quasars from the WFPC2 and NICMOS instruments aboard HST. I use narrow-band images centered on the Hβ, [OII]λ3727, [OIII]λ5007, and Paα emission lines to construct extinction and star formation maps. Additionally, I use line-ratio maps to distinguish AGN-powered line emission from star formation powered line emission. I find star formation, albeit at rates are lower than expected, suggesting that quasar host galaxies are dynamically more advanced than suspected. Seven of the galaxies have higher mass-specific star-formation rates. Additionally, I see evidence of shocked gas, supporting the hypotheses from earlier works that AGN activity quenches star formation in host galaxies by disrupting gas reservoirs.

  9. Cosmic strings and galaxy formation

    NASA Technical Reports Server (NTRS)

    Bertschinger, Edmund

    1989-01-01

    The cosmogonical model proposed by Zel'dovich and Vilenkin (1981), in which superconducting cosmic strings act as seeds for the origin of structure in the universe, is discussed, summarizing the results of recent theoretical investigations. Consideration is given to the formation of cosmic strings, the microscopic structure of strings, gravitational effects, cosmic string evolution, and the formation of galaxies and large-scale structure. Simulation results are presented in graphs, and several outstanding issues are listed and briefly characterized.

  10. Star formation in dwarf galaxies

    NASA Astrophysics Data System (ADS)

    Dong, Shawfeng

    In this thesis, we examine the star formation history and stellar feedback effects of dwarf galaxies under the influence of extragalactic ultraviolet radiation, as well as the evolution of residual gas within tidally-limited dwarf galaxies and globular clusters. Previous work has indicated that the background UV flux can easily ionize the gas within typical dwarf galaxies, delaying or even preventing cooling and star formation within them. Many dwarf galaxies within the Local Group are, however, observed to contain multiple generations of stars, the oldest of which formed in the early epochs of cosmic evolution, when the background UV flux was intense. In order to address this paradox, we consider the dynamical evolution of gas in dwarf galaxies using a one-dimensional, spherically symmetric, Lagrangian numerical scheme which also computes the effects of radiative transfer and photoionization. We include in the scheme a physically-motivated star formation recipe and consider the effects of feedback. This scheme allows us to follow the history of the gas and of star formation within dwarf galaxies, as influenced by both external and internal UV radiation. Our results indicate that star formation in the severe environment of dwarf galaxies is a difficult and inefficient process. In potentials with total mass less than a few 106 M⊙ , and velocity dispersion less than a few km s-1 , residual gas is efficiently photoionized by cosmic background UV radiation. For intermediate mass systems, such as the dSphs around the Galaxy, star formation can proceed within early cosmic epochs despite the intense background UV flux. Triggering processes such as merger events, collisions, and tidal disturbance can lead to density enhancements, reducing the recombination timescale, allowing gas to cool and star formation to proceed. However, the star formation and gas retention efficiency may vary widely in galaxies with similar dark matter potentials, because they depend on many

  11. Graben formation and dike arrest during the 2009 Harrat Lunayyir dike intrusion in Saudi Arabia: Insights from InSAR, stress calculations and analog experiments

    NASA Astrophysics Data System (ADS)

    Xu, Wenbin; Jónsson, Sigurjón; Corbi, Fabio; Rivalta, Eleonora

    2016-04-01

    Detailed spatial and temporal accounts of propagating dikes from crustal deformation data, including their interplay with faulting, are rare, leaving many questions about how this interplay affects graben formation and the arrest of dikes unanswered. Here we use interferometric synthetic aperture radar (InSAR) observations, stress calculations, and analog experiments to investigate the interaction between an intruding dike and normal faulting during the 2009 Harrat Lunayyir dike intrusion in western Saudi Arabia. We generated five displacement maps from InSAR data to unravel the temporal evolution of deformation covering the majority of the intrusion. We find that the observed surface displacements can be modeled by a ~2 m thick dike with an upper tip ~2 km below the surface on 16 May 2009, 4 weeks after the onset of seismic unrest. In the following three days, the dike propagated to within ~1 km of the surface with graben-bounding normal faulting dominating the near-field deformation. The volume of the dike doubled between mid-May and mid-June. We carried out analog experiments that indicate that the wedge-shaped graben grew outward with the faulting style changing progressively from normal faulting to oblique. Coulomb failure stress change calculations show that the intruding dike caused two zones of shallow horizontal tension on both sides of the dike, producing two zones of fissuring and normal faulting at the surface. In return, the faulting provoked compression around the upper tip of the dike, holding back its vertical propagation.

  12. Treating tar sands formations with karsted zones

    SciTech Connect

    Vinegar, Harold J.; Karanikas, John Michael

    2010-03-09

    Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

  13. Isolated star formation: from cloud formation to core collapse.

    PubMed

    Ward-Thompson, Derek

    2002-01-01

    The formation of stars is one of the most fundamental problems in astrophysics, as it underlies many other questions, on scales from the formation of galaxies to the formation of the solar system. The physical processes involve the turbulent behavior of a partially ionized medium containing a non-uniform magnetic field. Current debate centers around the time taken for turbulence to decay and the relative importance of the roles played by magnetic fields and turbulence. Technological advances such as millimeter-wave cameras have made possible observations of the temperature and density profiles, and statistical calculations of the lifetimes, of objects collapsing under their own self-gravity and those on the verge of collapse. Increased computing power allows more complex models to be made that include magnetic and turbulent effects. No current model can reproduce all of the observations. PMID:11778038

  14. An Adaptable Seismic Data Format

    NASA Astrophysics Data System (ADS)

    Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; de Andrade, Elliott Sales; Podhorszki, Norbert; Bozdağ, Ebru; Tromp, Jeroen

    2016-11-01

    We present ASDF, the Adaptable Seismic Data Format, a modern and practical data format for all branches of seismology and beyond. The growing volume of freely available data coupled with ever expanding computational power opens avenues to tackle larger and more complex problems. Current bottlenecks include inefficient resource usage and insufficient data organization. Properly scaling a problem requires the resolution of both these challenges, and existing data formats are no longer up to the task. ASDF stores any number of synthetic, processed or unaltered waveforms in a single file. A key improvement compared to existing formats is the inclusion of comprehensive meta information, such as event or station information, in the same file. Additionally, it is also usable for any non-waveform data, for example, cross-correlations, adjoint sources or receiver functions. Last but not least, full provenance information can be stored alongside each item of data, thereby enhancing reproducibility and accountability. Any data set in our proposed format is self-describing and can be readily exchanged with others, facilitating collaboration. The utilization of the HDF5 container format grants efficient and parallel I/O operations, integrated compression algorithms and check sums to guard against data corruption. To not reinvent the wheel and to build upon past developments, we use existing standards like QuakeML, StationXML, W3C PROV and HDF5 wherever feasible. Usability and tool support are crucial for any new format to gain acceptance. We developed mature C/Fortran and Python based APIs coupling ASDF to the widely used SPECFEM3D_GLOBE and ObsPy toolkits.

  15. The Dynamics of Latifundia Formation

    PubMed Central

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia. PMID:24376597

  16. The dynamics of latifundia formation.

    PubMed

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia. PMID:24376597

  17. The dynamics of latifundia formation.

    PubMed

    Chaves, Luis Fernando

    2013-01-01

    Land tenure inequity is a major social problem in developing nations worldwide. In societies, where land is a commodity, inequities in land tenure are associated with gaps in income distribution, poverty and biodiversity loss. A common pattern of land tenure inequities through the history of civilization has been the formation of latifundia [Zhuāngyuán in chinese], i.e., a pattern where land ownership is concentrated by a small fraction of the whole population. Here, we use simple Markov chain models to study the dynamics of latifundia formation in a heterogeneous landscape where land can transition between forest, agriculture and recovering land. We systematically study the likelihood of latifundia formation under the assumption of pre-capitalist trade, where trade is based on the average utility of land parcels belonging to each individual landowner during a discrete time step. By restricting land trade to that under recovery, we found the likelihood of latifundia formation to increase with the size of the system, i.e., the amount of land and individuals in the society. We found that an increase of the transition rate for land use changes, i.e., how quickly land use changes, promotes more equitable patterns of land ownership. Disease introduction in the system, which reduced land profitability for infected individual landowners, promoted the formation of latifundia, with an increased likelihood for latifundia formation when there were heterogeneities in the susceptibility to infection. Finally, our model suggests that land ownership reforms need to guarantee an equitative distribution of land among individuals in a society to avoid the formation of latifundia.

  18. Modeling of Mitochondrial Donut Formation

    PubMed Central

    Long, Qi; Zhao, Danyun; Fan, Weimin; Yang, Liang; Zhou, Yanshuang; Qi, Juntao; Wang, Xin; Liu, Xingguo

    2015-01-01

    Mitochondria are highly dynamic cell organelles. Continual cycles of fusion and fission play an important role in mitochondrial metabolism and cellular signaling. Previously, a novel mitochondrial morphology, the donut, was reported in cells after hypoxia-reoxygenation or osmotic pressure changes. However, the mechanism of donut formation remained elusive. Here, we obtained the distribution of donut diameters (D = 2R) and found that 95% are >0.8 μm. We also performed highly precise measurements of the mitochondrial tubule diameters using superresolution and electron microscopy. Then, we set up a model by calculating the mitochondrial bending energy and osmotic potential during donut formation. It shows that the bending energy is increased as the radius of curvature, R, gets smaller in the process of donut formation, especially for radii <0.4 μm, creating a barrier to donut formation. The calculations also show that osmotic potential energy release can balance the rising bending energy through volume expansion. Finally, we revealed the donut formation process in a Gibbs free-energy-dependent model combining calculations and measurements. PMID:26331247

  19. Star formation in Galactic flows

    NASA Astrophysics Data System (ADS)

    Smilgys, Romas; Bonnell, Ian A.

    2016-06-01

    We investigate the triggering of star formation in clouds that form in Galactic scale flows as the interstellar medium passes through spiral shocks. We use the Lagrangian nature of smoothed particle hydrodynamics simulations to trace how the star-forming gas is gathered into self-gravitating cores that collapse to form stars. Large-scale flows that arise due to Galactic dynamics create shocks of the order of 30 km s-1 that compress the gas and form dense clouds (n > several × 102 cm-3) in which self-gravity becomes relevant. These large-scale flows are necessary for creating the dense physical conditions for gravitational collapse and star formation. Local gravitational collapse requires densities in excess of n > 103 cm-3 which occur on size scales of ≈1 pc for low-mass star-forming regions (M < 100 M⊙), and up to sizes approaching 10 pc for higher mass regions (M > 103 M⊙). Star formation in the 250 pc region lasts throughout the 5 Myr time-scale of the simulation with a star formation rate of ≈10-1 M⊙ yr-1 kpc-2. In the absence of feedback, the efficiency of the star formation per free-fall time varies from our assumed 100 per cent at our sink accretion radius to values of <10-3 at low densities.

  20. Biofilm Formation by Candida dubliniensis

    PubMed Central

    Ramage, Gordon; Vande Walle, Kacy; Wickes, Brian L.; López-Ribot, José L.

    2001-01-01

    Candida dubliniensis is an opportunistic yeast closely related to Candida albicans that has been recently implicated in oropharyngeal candidiasis in human immunodeficiency virus-infected patients. Most manifestations of candidiasis are associated with biofilm formation, with cells in biofilms displaying properties dramatically different from free-living cells grown under normal laboratory conditions. Here, we report on the development of in vitro models of C. dubliniensis biofilms on the surfaces of biomaterials (polystyrene and acrylic) and on the characteristics associated with biofilm formation by this newly described species. Time course analysis using a formazan salt reduction assay to monitor metabolic activities of cells within the biofilm, together with microscopy studies, revealed that biofilm formation by C. dubliniensis occurred after initial focal adherence, followed by growth, proliferation, and maturation over 24 to 48 h. Serum and saliva preconditioning films enhanced the initial attachment of C. dubliniensis and subsequent biofilm formation. Scanning electron microscopy and confocal scanning laser microscopy were used to further characterize C. dubliniensis biofilms. Mature C. dubliniensis biofilms consisted of a dense network of yeasts cells and hyphal elements embedded within exopolymeric material. C. dubliniensis biofilms displayed spatial heterogeneity and an architecture showing microcolonies with ramifying water channels. Antifungal susceptibility testing demonstrated the increased resistance of sessile C. dubliniensis cells, including the type strain and eight different clinical isolates, against fluconazole and amphotericin B compared to their planktonic counterparts. C. dubliniensis biofilm formation may allow this species to maintain its ecological niche as a commensal and during infection with important clinical repercussions. PMID:11526156

  1. VLBI Data Interchange Format (VDIF)

    NASA Technical Reports Server (NTRS)

    Whitney, Alan; Kettenis, Mark; Phillips, Chris; Sekido, Mamoru

    2010-01-01

    One important outcome of the 7th International e-VLBI Workshop in Shanghai in June 2008 was the creation of a task force to study and recommend a universal VLBI data format that is suitable for both on-the-wire e-VLBI data transfer, as well as direct disk storage. This task force, called the VLBI Data Interchange Format (VDIF) Task Force, is the first part of a two-part effort, the second of which will address standardization of e-VLBI data-transmission-protocols. The formation of the VDIF Task Force was prompted particularly by increased e-VLBI activity and the difficulties encountered when data arrive at a correlator in different formats from various instruments in various parts of the world. The task force created a streaming packetized data format that may be used for real-time and non-realtime e-VLBI, as well as direct disk storage. The data may contain multiple channels of time-sampled data with an arbitrary number of channels, arbitrary #bits/sample up to 32, and real or complex data; data rates in excess of 100 Gbps are supported. Each data packet is completely self-identifying via a short header, and data may be decoded without reference to any external information. The VDIF task force has completed its work, and the VDIF standard was ratified at the 2009 e-VLBI workshop in Madrid.

  2. SW New Mexico Oil Well Formation Tops

    DOE Data Explorer

    Shari Kelley

    2015-10-21

    Rock formation top picks from oil wells from southwestern New Mexico from scout cards and other sources. There are differing formation tops interpretations for some wells, so for those wells duplicate formation top data are presented in this file.

  3. Physicochemical regulation of biofilm formation

    PubMed Central

    Renner, Lars D.; Weibel, Douglas B.

    2011-01-01

    This article reviews the physical and chemical constraints of environments on biofilm formation. We provide a perspective on how materials science and engineering can address fundamental questions and unmet technological challenges in this area of microbiology, such as biofilm prevention. Specifically, we discuss three factors that impact the development and organization of bacterial communities. (1) Physical properties of surfaces regulate cell attachment and physiology and affect early stages of biofilm formation. (2) Chemical properties influence the adhesion of cells to surfaces and their development into biofilms and communities. (3) Chemical communication between cells attenuates growth and influences the organization of communities. Mechanisms of spatial and temporal confinement control the dimensions of communities and the diffusion path length for chemical communication between biofilms, which, in turn, influences biofilm phenotypes. Armed with a detailed understanding of biofilm formation, researchers are applying the tools and techniques of materials science and engineering to revolutionize the study and control of bacterial communities growing at interfaces. PMID:22125358

  4. Jet-Induced Star Formation

    SciTech Connect

    van Breugel, W; Fragile, C; Anninos, P; Murray, S

    2003-12-16

    Jets from radio galaxies can have dramatic effects on the medium through which they propagate. We review observational evidence for jet-induced star formation in low ('FR-I') and high ('FR-II') luminosity radio galaxies, at low and high redshifts respectively. We then discuss numerical simulations which are aimed to explain a jet-induced starburst ('Minkowski's Object') in the nearby FR-I type radio galaxy NGC 541. We conclude that jets can induce star formation in moderately dense (10 cm{sup -3}), warm (10{sup 4} K) gas; that this may be more common in the dense environments of forming, active galaxies; and that this may provide a mechanism for 'positive' feedback from AGN in the galaxy formation process.

  5. Bundle Formation in Biomimetic Hydrogels.

    PubMed

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

  6. Spatial competition and price formation

    NASA Astrophysics Data System (ADS)

    Nagel, Kai; Shubik, Martin; Paczuski, Maya; Bak, Per

    2000-12-01

    We look at price formation in a retail setting, that is, companies set prices, and consumers either accept prices or go someplace else. In contrast to most other models in this context, we use a two-dimensional spatial structure for information transmission, that is, consumers can only learn from nearest neighbors. Many aspects of this can be understood in terms of generalized evolutionary dynamics. In consequence, we first look at spatial competition and cluster formation without price. This leads to establishement size distributions, which we compare to reality. After some theoretical considerations, which at least heuristically explain our simulation results, we finally return to price formation, where we demonstrate that our simple model with nearly no organized planning or rationality on the part of any of the agents indeed leads to an economically plausible price.

  7. Angular momentum and star formation

    NASA Astrophysics Data System (ADS)

    Strittmatter, P. A.

    The present investigation is mainly concerned with the importance of high angular resolution observations in studies of star formation and, in particular, with elucidating the role which angular momentum plays in the process. A brief report is included on recent high angular resolution observations made with the Steward Observatory speckle camera system. A consideration of the angular momentum in interstellar clouds indicates that rotation precludes quasi-spherical contraction. A number of solutions to this angular momentum problem are examined, taking into account questions concerning the help provided by high angular resolution observations for an elucidation of the various possible scenarios of star formation. Technical aspects involved in obtaining suitable data are investigated. It is concluded that high angular resolution observations hold considerable promise for solving at least some of the problems associated with the role of angular momentum in star formation.

  8. Formation dynamics in geostationary ring

    NASA Astrophysics Data System (ADS)

    Spiridonova, Sofya

    2016-08-01

    A relative motion model for a satellite formation composed of two Earth-orbiting spacecraft located in the geostationary ring is developed taking into account major gravitational and non-gravitational forces. A previously existing model featuring perturbation due to J_2 is enhanced by the perturbations due to solar radiation pressure arising from unequal area-to-mass ratios, as well as the secular and long-periodic gravitational perturbations due to the Sun and the Moon. The extended relative motion model is validated using several typical formation geometries against a reference generated by numerical integration of the absolute orbits of the two spacecraft. The results of this work can find application in future on-orbit servicing and formation flying missions in near-geostationary orbit.

  9. Mathematical Models for Somite Formation

    PubMed Central

    Baker, Ruth E.; Schnell, Santiago; Maini, Philip K.

    2009-01-01

    Somitogenesis is the process of division of the anterior–posterior vertebrate embryonic axis into similar morphological units known as somites. These segments generate the prepattern which guides formation of the vertebrae, ribs and other associated features of the body trunk. In this work, we review and discuss a series of mathematical models which account for different stages of somite formation. We begin by presenting current experimental information and mechanisms explaining somite formation, highlighting features which will be included in the models. For each model we outline the mathematical basis, show results of numerical simulations, discuss their successes and shortcomings and avenues for future exploration. We conclude with a brief discussion of the state of modeling in the field and current challenges which need to be overcome in order to further our understanding in this area. PMID:18023728

  10. Granuloma Formation in Pulmonary Sarcoidosis

    PubMed Central

    Broos, Caroline E.; van Nimwegen, Menno; Hoogsteden, Henk C.; Hendriks, Rudi W.; Kool, Mirjam; van den Blink, Bernt

    2013-01-01

    Sarcoidosis is a granulomatous disorder of unknown cause, affecting multiple organs, but mainly the lungs. The exact order of immunological events remains obscure. Reviewing current literature, combined with careful clinical observations, we propose a model for granuloma formation in pulmonary sarcoidosis. A tight collaboration between macrophages, dendritic cells, and lymphocyte subsets, initiates the first steps toward granuloma formation, orchestrated by cytokines and chemokines. In a substantial part of pulmonary sarcoidosis patients, granuloma formation becomes an on-going process, leading to debilitating disease, and sometimes death. The immunological response, determining granuloma sustainment is not well understood. An impaired immunosuppressive function of regulatory T cells has been suggested to contribute to the exaggerated response. Interestingly, therapeutical agents commonly used in sarcoidosis, such as glucocorticosteroids and anti-TNF agents, interfere with granuloma integrity and restore the immune homeostasis in autoimmune disorders. Increasing insight into their mechanisms of action may contribute to the search for new therapeutical targets in pulmonary sarcoidosis. PMID:24339826

  11. An XML portable chart format.

    PubMed Central

    Chueh, H. C.; Raila, W. F.; Berkowicz, D. A.; Barnett, G. O.

    1998-01-01

    The clinical chart remains the fundamental record of outpatient clinical care. As this information migrates to electronic form, there is an opportunity to create standard formats for transmitting these charts. This paper describes work toward a Portable Chart Format (PCF) that can represent the relevant aspects of an outpatient chart. The main goal of the format is to provide a packaging medium for outpatient clinical charts in a transfer of care scenario. A secondary goal is to support the aggregation of comparable clinical data for outcomes analysis. The syntax used for PCF is Extended Markup Language (XML), a W3C standard. The structure of the PCF is based on a clinically relevant view of the data. The data definitions and nomenclature used are based primarily on existing clinical standards. PMID:9929315

  12. Pathophysiology of glioma cyst formation.

    PubMed

    Adn, Mahmoudreza; Saikali, Stephan; Guegan, Yvon; Hamlat, Abderrahmane

    2006-01-01

    Fluid filled cystic cavities are accompaniments of some cerebral gliomas. These tumoural cysts together with peritumoural vasogenic brain oedema add to the morbid effects of the gliomas in terms of mass effect and increased intracranial pressure. Although different mechanisms have been suggested as to the pathogenesis of glioma-associated cysts, it is still unclear why these cysts appear in only a limited number of cerebral gliomas while brain oedema, a probable precursor of glioma cysts, is a usual accompaniment of most gliomas. Here, the authors present a two-hit hypothesis of brain glioma cyst formation. We suggest that after the formation of vasogenic tumoural brain oedema, microvascular phenomena may lead to the formation of microcysts, which might later become confluent and grow to form macroscopic cysts. Progress in the understanding of pathogenesis of cerebral glioma cysts might set targets for treatment of brain edema and glioma cysts.

  13. Pattern formation in multiplex networks

    PubMed Central

    Kouvaris, Nikos E.; Hata, Shigefumi; Guilera, Albert Díaz-

    2015-01-01

    The advances in understanding complex networks have generated increasing interest in dynamical processes occurring on them. Pattern formation in activator-inhibitor systems has been studied in networks, revealing differences from the classical continuous media. Here we study pattern formation in a new framework, namely multiplex networks. These are systems where activator and inhibitor species occupy separate nodes in different layers. Species react across layers but diffuse only within their own layer of distinct network topology. This multiplicity generates heterogeneous patterns with significant differences from those observed in single-layer networks. Remarkably, diffusion-induced instability can occur even if the two species have the same mobility rates; condition which can never destabilize single-layer networks. The instability condition is revealed using perturbation theory and expressed by a combination of degrees in the different layers. Our theory demonstrates that the existence of such topology-driven instabilities is generic in multiplex networks, providing a new mechanism of pattern formation. PMID:26042606

  14. Physicochemical regulation of biofilm formation.

    PubMed

    Renner, Lars D; Weibel, Douglas B

    2011-05-01

    This article reviews the physical and chemical constraints of environments on biofilm formation. We provide a perspective on how materials science and engineering can address fundamental questions and unmet technological challenges in this area of microbiology, such as biofilm prevention. Specifically, we discuss three factors that impact the development and organization of bacterial communities. (1) Physical properties of surfaces regulate cell attachment and physiology and affect early stages of biofilm formation. (2) Chemical properties influence the adhesion of cells to surfaces and their development into biofilms and communities. (3) Chemical communication between cells attenuates growth and influences the organization of communities. Mechanisms of spatial and temporal confinement control the dimensions of communities and the diffusion path length for chemical communication between biofilms, which, in turn, influences biofilm phenotypes. Armed with a detailed understanding of biofilm formation, researchers are applying the tools and techniques of materials science and engineering to revolutionize the study and control of bacterial communities growing at interfaces.

  15. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the Λ cold dark matter (ΛCDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ~10(6) M⊙ and collapsing at redshifts z ≈ 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae.

  16. Conductive Anodic Filament (CAF) Formation

    NASA Astrophysics Data System (ADS)

    Caputo, Antonio

    Conductive anodic filament (CAF) is a failure mode in printed wiring boards (PWBs) which occurs under high humidity and high voltage gradient conditions. The filament, a copper salt, grows from anode to cathode along the epoxy-glass interface. Ready and Turbini (2000) identified this copper salt as the Cu 2(OH)3Cl, atacamite compound. This work has investigated the influence of polyethylene glycol (PEG) and polyethylene propylene glycol (PEPG) fluxing agents on the chemical nature of CAF. For coupons processed with PEPG flux, with and without chloride, a copper-chloride containing compound was formed in the polymer matrix. This compound was characterized using x-ray photoelectron spectroscopy (XPS) as CuCl and an electrochemical mechanism for the formation of the chloride-containing CAF has been proposed. For PEG flux, with and without chloride, it has been shown that CAF only formed, but no copper containing compound formed in the matrix. It appears for PEG fluxed coupons, a PEG-Cu-Cl complex forms, binds the available Cu and acts as a barrier to the formation of CuCl in the polymer matrix. Meeker and Lu Valle (1995) have previously proposed that CAF failure is best represented by two competing reactions -- the formation of a copper chloride corrosion compound (now identified as Cu2(OH)3Cl) and the formation of innocuous trapped chlorine compounds. Since no evidence of any trapped chloride compounds has been found, we propose that the formation of CAF is best represented by a single non-reversible reaction. For coupons processed with a high bromide-containing flux, bromide containing CAF was created and characterized using transmission electron microscopy (TEM) to be Cu2(OH)3Br. In addition, a copper-containing compound was formed in the polymer matrix and characterized using XPS as CuBr. An electrochemical mechanism for the formation of bromide-containing CAF has been proposed based on the XPS data.

  17. Formation of the first stars.

    PubMed

    Bromm, Volker

    2013-11-01

    Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signalled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a fundamental transformation of the early Universe through the production of ionizing photons and the initial enrichment with heavy chemical elements. We here review the state of our knowledge, separating the well understood elements of our emerging picture from those where more work is required. Primordial star formation is unique in that its initial conditions can be directly inferred from the Λ cold dark matter (ΛCDM) model of cosmological structure formation. Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial star formation, the so-called minihalos, having total masses of ~10(6) M⊙ and collapsing at redshifts z ≈ 20-30. Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive. This model has recently been modified to include a ubiquitous mode of fragmentation in the protostellar disks, such that the typical outcome of primordial star formation may be the formation of a binary or small multiple stellar system. We will also discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihalating WIMP dark matter, or cosmic rays. We conclude by discussing possible strategies to empirically test our theoretical models. Foremost among them are predictions for the upcoming James Webb space telescope (JWST), to be launched ~2018, and for 'stellar archaeology', which probes the abundance pattern in the oldest, most-metal poor stars in our cosmic neighborhood, thereby constraining the nucleosynthesis inside the first supernovae. PMID:24168986

  18. Optimal Reconfiguration of Tetrahedral Formations

    NASA Technical Reports Server (NTRS)

    Huntington, Geoffrey; Rao, Anil V.; Hughes, Steven P.

    2004-01-01

    The problem of minimum-fuel formation reconfiguration for the Magnetospheric Multi-Scale (MMS) mission is studied. This reconfiguration trajectory optimization problem can be posed as a nonlinear optimal control problem. In this research, this optimal control problem is solved using a spectral collocation method called the Gauss pseudospectral method. The objective of this research is to provide highly accurate minimum-fuel solutions to the MMS formation reconfiguration problem and to gain insight into the underlying structure of fuel-optimal trajectories.

  19. Star formation and gas supply

    NASA Astrophysics Data System (ADS)

    Catinella, B.

    2016-06-01

    A detailed knowledge of how gas cycles in and around galaxies, and how it depends on galaxy properties such as stellar mass and star formation rate, is crucial to understand galaxy formation and evolution. We take advantage of the most sensitive surveys of cold gas in massive galaxies, GASS and COLD GASS, as well as of the state-of-the-art HI blind survey ALFALFA to investigate how molecular and atomic hydrogen reservoirs vary along and across the main sequence of star-forming galaxies.

  20. Magnetohydrodynamic mechanism for pedestal formation.

    PubMed

    Guazzotto, L; Betti, R

    2011-09-16

    Time-dependent two-dimensional magnetohydrodynamic simulations are carried out for tokamak plasmas with edge poloidal flow. Differently from conventional equilibrium theory, a density pedestal all around the edge is obtained when the poloidal velocity exceeds the poloidal sound speed. The outboard pedestal is induced by the transonic discontinuity, the inboard one by mass redistribution. The density pedestal follows the formation of a highly sheared flow at the transonic surface. These results may be relevant to the L-H transition and pedestal formation in high performance tokamak plasmas.

  1. Star formation and extinct radioactivities

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1984-01-01

    An assessment is made of the evidence for the existence of now-extinct radioactivities in primitive solar system material, giving attention to implications for the early stages of sun and solar system formation. The characteristics of possible disturbances in dense molecular clouds which can initiate the formation of cloud cores is discussed, with emphasis on these disturbances able to generate fresh radioactivities. A one-solar mass red giant star on the asymptotic giant branch appears to have been the best candidate to account for the short-lived extinct radioactivities in the early solar system.

  2. Pattern formation in the geosciences

    PubMed Central

    Goehring, Lucas

    2013-01-01

    Pattern formation is a natural property of nonlinear and non-equilibrium dynamical systems. Geophysical examples of such systems span practically all observable length scales, from rhythmic banding of chemical species within a single mineral crystal, to the morphology of cusps and spits along hundreds of kilometres of coastlines. This article briefly introduces the general principles of pattern formation and argues how they can be applied to open problems in the Earth sciences. Particular examples are then discussed, which summarize the contents of the rest of this Theme Issue. PMID:24191107

  3. Star formation and its triggers

    NASA Astrophysics Data System (ADS)

    Combes, F.

    2016-06-01

    The relation between star formation and gas density appears linear for galaxies on the main sequence, and when the molecular gas is considered. However, the star formation efficiency (SFE) defined as the ratio of SFR to gas surface densities, can be much higher when SF is triggered by a dynamical process such as galaxy interaction or mergers, or even secular evolution and cold gas accretion. I review recent work showing how the SFE can vary as a function of morphological type, environment, or redshift. Physical processes able to explain positive and negative feedback from supernovae or AGN are discussed.

  4. Star formation across galactic environments

    NASA Astrophysics Data System (ADS)

    Young, Jason

    I present here parallel investigations of star formation in typical and extreme galaxies. The typical galaxies are selected to be free of active galactic nuclei (AGN), while the extreme galaxies host quasars (the most luminous class of AGN). These two environments are each insightful in their own way; quasars are among the most violent objects in the universe, literally reshaping their host galaxies, while my sample of AGN-free star-forming galaxies ranges from systems larger than the Milky Way to small galaxies which are forming stars at unsustainably high rates. The current paradigm of galaxy formation and evolution suggests that extreme circumstances are key stepping stones in the assembly of galaxies like our Milky Way. To test this paradigm and fully explore its ramifications, this dual approach is needed. My sample of AGN-free galaxies is drawn from the KPNO International Spectroscopic Survey. This Halpha-selected, volume-limited survey was designed to detect star-forming galaxies without a bias toward continuum luminosity. This type of selection ensures that this sample is not biased toward galaxies that are large or nearby. My work studies the KISS galaxies in the mid- and far-infrared using photometry from the IRAC and MIPS instruments aboard the Spitzer Space Telescope. These infrared bands are particularly interesting for star formation studies because the ultraviolet light from young stars is reprocessed into thermal emission in the far-infrared (24mum MIPS) by dust and into vibrational transitions features in the mid-infrared (8.0mum IRAC) by polycyclic aromatic hydrocarbons (PAHs). The work I present here examines the efficiencies of PAH and thermal dust emission as tracers of star-formation rates over a wide range of galactic stellar masses. I find that the efficiency of PAH as a star-formation tracer varies with galactic stellar mass, while thermal dust has a highly variable efficiency that does not systematically depend on galactic stellar mass

  5. SAS FORMATS: USES AND ABUSES

    EPA Science Inventory

    SAS formats are a very powerful tool. They allow you to display the data in a more readable manner without modifying the data. They can also be used to group data into categories for use in various procedures like PROC FREQ, PROC TTEST, and PROC MEANS (as a class variable). ...

  6. Facial Prototype Formation in Children.

    ERIC Educational Resources Information Center

    Inn, Donald; And Others

    This study examined memory representation as it is exhibited in young children's formation of facial prototypes. In the first part of the study, researchers constructed images of faces using an Identikit that provided the features of hair, eyes, mouth, nose, and chin. Images were varied systematically. A series of these images, called exemplar…

  7. Chevrons formation in laminar erosion

    NASA Astrophysics Data System (ADS)

    Devauchelle, Olivier; Josserand, Christophe; Lagree, Pierre-Yves; Zaleski, Stephane; Nguyen, Khanh-Dang; Malverti, Luce; Lajeunesse, Eric

    2007-11-01

    When eroded by laminar free-surface flows, granular substrates may generate a rich variety of natural patterns. Among them are dunes, similar to the ones observed by Charru and Hinch in a Couette cell (Charru F, Hinch EJ ; Ripple formation on a particle bed sheared by a viscous liquid. Part 1. Steady flow ; JOURNAL OF FLUID MECHANICS 550: 111-121 MAR 10 2006). Chevron-shaped instabilities as those found on the sea-shore, can also be observed, sometimes in competition against dunes formation. These were first pointed out by Daerr et al. when pulling a plate covered with granular material out of a bath of water (Daerr A, Lee P, Lanuza J, et al. ; Erosion patterns in a sediment layer ; PHYSICAL REVIEW E 67 (6): Art. No. 065201 Part 2 JUN 2003). Both instabilities can grow in laminar open-channel flows, an experimental set-up which is more easily controlled. The mechanisms leading to the formation of these patterns are investigated and compared. Whereas dunes formation requires vertical inertia effects, we show that chevrons may result from the non-linear evolution of bars instability, which may grow even in purely viscous flows.

  8. Junction formation during desiccation cracking.

    PubMed

    Toga, K B; Alaca, B Erdem

    2006-08-01

    In order to provide a sound physical basis for the understanding of the formation of desiccation crack networks, an experimental study is presented addressing junction formation. Focusing on junctions, basic features of the network determining the final pattern, provides an elemental approach and imparts conceptual clarity to the rather complicated problem of the evolution of crack patterns. Using coffee-water mixtures a clear distinction between junction formation during nucleation and propagation is achieved. It is shown that for the same drying suspension, one can switch from the well-known symmetric triple junctions that are unique to the nucleation phase to propagation junctions that are purely dictated by the variations of the stress state. In the latter case, one can even manipulate the path of a propagating crack in a deterministic fashion by changing the stress state within the suspension. Clear microscopic evidence is provided for the formation of propagation junctions, and material inhomogeneity is observed to be reflected by a broad distribution of angles, in stark contrast to shrinkage cracks in homogeneous solid films.

  9. Formative Assessment in Primary Science

    ERIC Educational Resources Information Center

    Loughland, Tony; Kilpatrick, Laetitia

    2015-01-01

    This action learning study in a year three classroom explored the implementation of five formative assessment principles to assist students' understandings of the scientific topic of liquids and solids. These principles were employed to give students a greater opportunity to express their understanding of the concepts. The study found that…

  10. Laser-assisted antihydrogen formation

    SciTech Connect

    Chattopadhyay, A.; Sinha, C.

    2006-08-15

    Laser-assisted antihydrogen (H) formation cross sections (differential and total) for collisions of antiprotons with positronium (Ps) are studied in the framework of the eikonal approximation for two geometries, when the field polarization is parallel (parallel{sup L}) or perpendicular (perpendicular{sup r}) to the incident Ps momentum. The variations of the H formation cross sections with respect to the field strength and the laser photon energy are studied for the multiphoton (absorption and emission) processes. The contribution of the atomic (both Ps and H) dressing terms to the enhancement of the H formation cross section is studied for both the geometries (parallel{sup L} and (perpendicular{sup r}). The most important prediction from the present work is the enhancement of the field-free (FF) H formation cross sections particularly at lower incident energies when the system (Ps+p) is irradiated by a single mode, linearly polarized laser, the enhancement being more pronounced for a wider range of incident energy in the perpendicular{sup r} geometry than in the parallel{sup L} one.

  11. Pattern Formation in Convective Instabilities

    NASA Astrophysics Data System (ADS)

    Friedrich, R.; Bestehorn, M.; Haken, H.

    The present article reviews recent progress in the study of pattern formation in convective instabilities. After a brief discussion of the relevant basic hydrodynamic equations as well as a short outline of the mathematical treatment of pattern formation in complex systems the self-organization of spatial and spatio-temporal structures due to convective instabilities is considered. The formation of various forms of convective patterns arising in the Bénard experiment, i.e. in a horizontal fluid layer heated from below, is discussed. Then the review considers pattern formation in the Bénard instability in spherical geometries. In that case it can be demonstrated how the interaction among several convective cells may lead to time dependent as well as chaotic evolution of the spatial structures. Finally, the convective instability in a binary fluid mixture is discussed. In contrast to the instability in a single component fluid the instability may be oscillatory. In that case convection sets in in the form of travelling wave patterns which in addition to a complicated and chaotic temporal behaviour exhibit more or less spatial irregularity already close to threshold.

  12. Formative Assessment in Dance Education

    ERIC Educational Resources Information Center

    Andrade, Heidi; Lui, Angela; Palma, Maria; Hefferen, Joanna

    2015-01-01

    Feedback is crucial to students' growth as dancers. When used within the framework of formative assessment, or assessment for learning, feedback results in actionable next steps that dancers can use to improve their performances. This article showcases the work of two dance specialists, one elementary and one middle school teacher, who have…

  13. A standard audit trail format

    SciTech Connect

    Bishop, M.

    1995-02-01

    The central role of audit trails, or (more properly) logs, in security monitoring needs little description, for it is too well known for any to doubt it. Auditing, or the analysis of logs, is a central part of security not only in computer system security but also in analyzing financial and other non-technical systems. As part of this process, it is often necessary to reconcile logs from different sources. This speaks of a need for a standard logging format. A standard log format robust enough to meet the needs of heterogeneity, transportability across various network protocols, and flexibility sufficient to meet a variety of needs in very different environments must satisfy two basic properties: extensibility and portability. This report presents the author`s proposed format for a standard log record. In section 3, he shows how and where the translation should be done, and in section 4 he demonstrates how log records from several disparate systems would be put into this format. Section 5 concludes with some observations and suggestions for future work.

  14. Stereotype Formation: Biased by Association

    ERIC Educational Resources Information Center

    Le Pelley, Mike E.; Reimers, Stian J.; Calvini, Guglielmo; Spears, Russell; Beesley, Tom; Murphy, Robin A.

    2010-01-01

    We propose that biases in attitude and stereotype formation might arise as a result of learned differences in the extent to which social groups have previously been predictive of behavioral or physical properties. Experiments 1 and 2 demonstrate that differences in the experienced predictiveness of groups with respect to evaluatively neutral…

  15. The EPRDATA Format: A Dialogue

    SciTech Connect

    Hughes, III, Henry Grady

    2015-08-18

    Recently the Los Alamos Nuclear Data Team has communicated certain issues of concern in relation to the new electron/photon/relaxation ACE data format as released in the eprdata12 library. In this document those issues are parsed, analyzed, and answered.

  16. Formative Assessment: A Cybernetic Viewpoint

    ERIC Educational Resources Information Center

    Roos, Bertil; Hamilton, David

    2005-01-01

    This paper considers alternative assessment, feedback and cybernetics. For more than 30 years, debates about the bi-polarity of formative and summative assessment have served as surrogates for discussions about the workings of the mind, the social implications of assessment and, as important, the role of instruction in the advancement of learning.…

  17. Technology Enhanced Distributive Formative Evaluation

    ERIC Educational Resources Information Center

    Moore, David Richard

    2008-01-01

    Quality assurance in instructional development demands an exhaustive formative evaluation effort and applied testing. Unfortunately, this process is expensive and requires large numbers of user testers with characteristics similar to the intended audience. This article presents a procedure for increasing the efficiency of quality assurance efforts…

  18. Multiple cilia suppress tumour formation.

    PubMed

    Eberhart, Charles

    2016-04-01

    Primary cilia are cellular structures that have important functions in development and disease. The suppression of multiciliate differentiation of choroid plexus precursors, and maintenance of a single primary cilium by Notch1, is now shown to be involved in choroid plexus tumour formation. PMID:27027488

  19. Formative Considerations Using Integrative CALL.

    ERIC Educational Resources Information Center

    Callahan, Philip; Shaver, Peter

    2001-01-01

    Addresses technical and learning issues relating to a formative implementation of a computer assisted language learning (CALL) browser-based intermediate Russian program. Instruction took place through a distance education implementation and in a grouped classroom using a local-area network. Learners indicated the software was clear, motivating,…

  20. Audiences for Contemporary Radio Formats.

    ERIC Educational Resources Information Center

    Lull, James T.; And Others

    A radio audience survey of 110 sample geographic clusters in the Santa Barbara, California, area served a twofold purpose: the construction of a demographic profile of audience types according to radio format choices, and the identification and analysis of various audience subgroups. A skip interval technique of these geographic clusters resulted…

  1. Constraints on galaxy formation theories

    NASA Technical Reports Server (NTRS)

    Szalay, A. S.

    1986-01-01

    The present theories of galaxy formation are reviewed. The relation between peculiar velocities, temperature fluctuations of the microwave background and the correlation function of galaxies point to the possibility that galaxies do not form uniformly everywhere. The velocity data provide strong constraints on the theories even in the case when light does not follow mass of the universe.

  2. Amyloid Beta Mediates Memory Formation

    ERIC Educational Resources Information Center

    Garcia-Osta, Ana; Alberini, Cristina M.

    2009-01-01

    The amyloid precursor protein (APP) undergoes sequential cleavages to generate various polypeptides, including the amyloid [beta] (1-42) peptide (A[beta][1-42]), which is believed to play a major role in amyloid plaque formation in Alzheimer's disease (AD). Here we provide evidence that, in contrast with its pathological role when accumulated,…

  3. Mantle dynamics following supercontinent formation

    NASA Astrophysics Data System (ADS)

    Heron, Philip J.

    This thesis presents mantle convection numerical simulations of supercontinent formation. Approximately 300 million years ago, through the large-scale subduction of oceanic sea floor, continental material amalgamated to form the supercontinent Pangea. For 100 million years after its formation, Pangea remained relatively stationary, and subduction of oceanic material featured on its margins. The present-day location of the continents is due to the rifting apart of Pangea, with supercontinent dispersal being characterized by increased volcanic activity linked to the generation of deep mantle plumes. The work presented here investigates the thermal evolution of mantle dynamics (e.g., mantle temperatures and sub-continental plumes) following the formation of a supercontinent. Specifically, continental insulation and continental margin subduction are analyzed. Continental material, as compared to oceanic material, inhibits heat flow from the mantle. Previous numerical simulations have shown that the formation of a stationary supercontinent would elevate sub-continental mantle temperatures due to the effect of continental insulation, leading to the break-up of the continent. By modelling a vigorously convecting mantle that features thermally and mechanically distinct continental and oceanic plates, this study shows the effect of continental insulation on the mantle to be minimal. However, the formation of a supercontinent results in sub-continental plume formation due to the re-positioning of subduction zones to the margins of the continent. Accordingly, it is demonstrated that continental insulation is not a significant factor in producing sub-supercontinent plumes but that subduction patterns control the location and timing of upwelling formation. A theme throughout the thesis is an inquiry into why geodynamic studies would produce different results. Mantle viscosity, Rayleigh number, continental size, continental insulation, and oceanic plate boundary evolution are

  4. Sedimentary pyrite formation: An update

    NASA Astrophysics Data System (ADS)

    Berner, Robert A.

    1984-04-01

    Sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time. The amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter, dissolved sulfate, and reactive detrital iron minerals. Organic matter appears to be the major control on pyrite formation in normal (non-euxinic) terrigenous marine sediments where dissolved sulfate and iron minerals are abundant. By contrast, pyrite formation in non-marine, freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic-rich fresh water shales from marine shales. Under marine euxinic conditions sufficient H 2S is produced that the dominant control on pyrite formation is the availability of reactive iron minerals. Calculations, based on a sulfur isotope model, indicate that over Phanerozoic time the worldwide average organic carbon-to-pyrite sulfur ratio of sedimentary rocks has varied considerably. High C/S ratios during Permo-Carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time. Low C/S ratios, compared to today, during the early Paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean. The latter could have been due to lower oceanic oxygen levels and/or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time.

  5. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew R.; Piro, Anthony; Ott, Christian D.

    2015-01-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. Using the observed BH mass distribution from Galactic X-ray binaries, we investigate the probability that a star will make a BH as a function of its ZAMS mass. Although the shape of the black hole formation probability function is poorly constrained by current measurements, we believe that this framework is an important new step toward better understanding BH formation. We also consider some of the implications of this probability distribution, from its impact on the chemical enrichment from massive stars, to its connection with the structure of the core at the time of collapse, to the birth kicks that black holes receive. A probabilistic description of BH formation will be a useful input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  6. Inside-Out Planet Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Chatterjee, Sourav

    2013-07-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theory. Formation in situ from disks with radial mass surface density profiles similar to the minimum mass solar nebula (MMSN) but boosted in normalization by factors >10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles", drifting inwards via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magneto-rotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ~1-10M_Earth planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead zone boundary. Our simple theoretical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly-packed system architectures, starting from typical protoplanetary disk properties.

  7. Inside-out Planet Formation

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sourav; Tan, Jonathan C.

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors >~ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles," drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ~1 M ⊕ planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  8. Inside-out planet formation

    SciTech Connect

    Chatterjee, Sourav; Tan, Jonathan C. E-mail: jt@astro.ufl.edu

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ≳ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (∼cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ∼1 M {sub ⊕} planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  9. Wintertime Haze Formation in Beijing

    NASA Astrophysics Data System (ADS)

    Levy Zamora, M. E.

    2015-12-01

    Recent severe haze events in China have attracted significant public attention due to the severely reduced visibility and unprecedentedly high pollutant concentrations. Particular attention has been given to the high concentrations of particulate matter with a diameter less than 2.5 microns (PM2.5), which can exceed several hundred micrograms per cubic meter over several days. During January and February of 2015, a suite of aerosol instruments was deployed in Beijing to directly measure a comprehensive set of aerosol properties, including the particle size distribution, effective density, and chemical composition. In this presentation, we will discuss the particulate matter formation mechanisms, the evolution of aerosol properties throughout the event, and how the winter formation mechanisms compare with the warmer seasons. We show that the periodic cycles of severe haze episodes in Beijing are largely driven by meteorological conditions. During haze events, stagnation typically develops as a result of a low planetary boundary layer and weak southerly wind from polluted industrial source regions. Stronger northerly winds were frequently observed during the clean period, which carry unpolluted air masses from the less populated northern mountainous areas. Nucleation consistently occurs on clean days, producing a high number concentration of nano particles. The particle mass concentration exceeding several hundred micrograms per cubic meter is attributed to the continuous size growth from the nucleation-mode particles (diameter less than 10 nm) over multiple days to produce a high concentration of larger particles (diameter greater than 100 nm). The particle chemical composition in Beijing is similar to those commonly measured in other urban centers, which is indicative of chemical constituents dominated by secondary aerosol formation. Our results reveal that the severe haze formation in Beijing during the wintertime is similar to the mechanism of haze formation

  10. Inside-Out Planet Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan Charles; Chatterjee, Sourav; Hu, Xiao; Zhu, Zhaohuan; Mohanty, Subhanjoy

    2015-08-01

    The Kepler-discovered systems with tightly-packed inner planets (STIPs), typically with several planets of Earth to super-Earth masses on well-aligned, sub-AU orbits may host the most common type of planets in the Galaxy. They pose a great challenge for planet formation theories, which fall into two broad classes: (1) formation further out followed by migration; (2) formation in situ from a disk of gas and planetesimals. I review the pros and cons of these classes, before focusing on a new theory of sequential in situ formation from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (~cm-m size) "pebbles," drifting inward via gas drag. Pebbles first collect at the pressure trap associated with the transition from a magnetorotational instability (MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an Earth to super-Earth-mass planet directly or induces gradual planet formation via core accretion. The planet continues to accrete until it becomes massive enough to isolate itself from the accretion flow via gap opening. The process repeats with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. I discuss the theory’s predictions for planetary masses, relative mass scalings with orbital radius, and minimum orbital separations, and their comparison with observed systems. Finally I speculate about potential causes of diversity of planetary system architectures, i.e., STIPs versus Solar System analogs.

  11. What Is Formation? A Conceptual Discussion

    ERIC Educational Resources Information Center

    Sutphen, Molly; de Lange, Thomas

    2015-01-01

    This paper addresses the principles and connotations of the term "formation." In our discussion of formation, we draw on different disciplines in order to widen and deepen our understanding of the concept of formation. We also mirror the formation concept against comparable terms and draw on studies in which it has been applied in…

  12. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  13. Standard Formats for Atomic Data: the APED

    SciTech Connect

    Smith, R K; Brickhouse, N S; Liedahl, D A; Raymond, J C

    2001-06-05

    Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.

  14. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  15. 40 CFR 1502.10 - Recommended format.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Recommended format. 1502.10 Section... § 1502.10 Recommended format. Agencies shall use a format for environmental impact statements which will... following standard format for environmental impact statements should be followed unless the...

  16. Method of fracturing a geological formation

    DOEpatents

    Johnson, James O.

    1990-01-01

    An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

  17. ASDF: A new data format for astronomy

    NASA Astrophysics Data System (ADS)

    Greenfield, P.; Droettboom, M.; Bray, E.

    2015-09-01

    We present the case for developing a successor format for the immensely successful FITS format. We first review existing alternative formats and discuss why we do not believe they provide an adequate solution. The proposed format is called the Advanced Scientific Data Format (ASDF) and is based on an existing text format, YAML, that we believe removes most of the current problems with the FITS format. An overview of the capabilities of the new format is given along with specific examples. This format has the advantage that it does not limit the size of attribute names (akin to FITS keyword names) nor place restrictions on the size or type of values attributes have. Hierarchical relationships are explicit in the syntax and require no special conventions. Finally, it is capable of storing binary data within the file in its binary form. At its basic level, the format proposed has much greater applicability than for just astronomical data.

  18. Field technique of permeability tests in highly fissured limestone strata

    NASA Astrophysics Data System (ADS)

    Al-Salihi, Adnan; Asaad, Abdulah

    2002-05-01

    Résumé.L'étude de dispositifs de dénoyage est nécessaire pour l'amélioration de sites avant la construction de certaines structures. L'étude de dispositifs de dénoyage efficaces exige d'estimer la valeur du coefficient de perméabilité in situ. Les relations disponibles pour estimer le coefficient de perméabilité ont été développées sur la base de mesures et de conditions de terrain limitées, et les prédictions varient de plusieurs ordres de grandeur. C'est pourquoi il est nécessaire de réaliser des mesures de perméabilité sur le terrain et de déterminer la relation qui permet le meilleur ajustement de ces mesures avant l'étude du dispositif de dénoyage pour des conditions locales et géologiques spécifiques. Ce papier présente des mesures de perméabilité sur le terrain dans des niveaux calcaires complexes chaotiques et diagénétisés. Il propose également une analyse comparative de plusieurs relations disponibles dans la littérature destinées à prédire le coefficient de perméabilité in situ. L'analyse est faite en conditions permanentes et non permanentes. Les résultats montrent que la valeur du coefficient de perméabilité dépend du niveau de la nappe, qui est affecté par le régime de marées. On montre que l'équation de l'US Navy donne la meilleure corrélation avec les mesures de terrain. Resumen.El diseño de sistemas de desecado es necesario para mejorar las condiciones de un emplazamiento antes de la construcción de determinadas estructuras. El diseño de un sistema eficiente de desecado requiere de la estimación del valor de la permeabilidad in-situ. Las relaciones disponibles para tal fin han sido desarrolladas bajo condiciones y medidas de campo limitadas; sus predicciones varían en algunos órdenes de magnitud. Por tanto, es necesario tomar medidas de permeabilidad en campo y determinar la relación que reproduce mejor dichas medidas como paso previo al diseño de un sistema de desecado en condiciones geológicas y de emplazamiento específicas. Este artículo presenta medidas de permeabilidad en campo para estratos de calcita caóticos y diagenéticos. También ofrece un análisis comparativo de diversas relaciones disponibles en la bibliografía con el fin de predecir el valor de la permeabilidad in-situ. El análisis se ha hecho tanto en régimen permanente como en estacionario. Los resultados demuestran que la permeabilidad depende del nivel freático, el cual está afectado por las mareas. La ecuación de la Marina estadounidense es la que proporciona una mejor correlación con las medidas de campo.

  19. Treating tar sands formations with dolomite

    DOEpatents

    Vinegar, Harold J.; Karanikas, John Michael

    2010-06-08

    Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

  20. Engineering biofilm formation and dispersal

    PubMed Central

    Wood, Thomas K.; Hong, Seok Hoon; Ma, Qun

    2011-01-01

    Anywhere water is in the liquid state, bacteria will exist as biofilms, which are complex communities of cells cemented together. Although frequently associated with disease and biofouling, biofilms are also important for engineering applications, such as bioremediation, biocatalysis and microbial fuel cells. Here we review approaches to alter genetic circuits and cell signaling toward controlling biofilm formation, and emphasize utilizing these tools for engineering applications. Based on a better understanding of the genetic basis of biofilm formation, we find that biofilms may be controlled by manipulating extracellular signals and that they may be dispersed using conserved intracellular signals and regulators. Biofilms could also be formed at specific locations where they might be engineered to make chemicals or treat human disease. PMID:21131080

  1. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  2. Laser beam pulse formatting method

    DOEpatents

    Daly, T.P.; Moses, E.I.; Patterson, R.W.; Sawicki, R.H.

    1994-08-09

    A method for formatting a laser beam pulse using one or more delay loops is disclosed. The delay loops have a partially reflective beam splitter and a plurality of highly reflective mirrors arranged such that the laser beam pulse enters into the delay loop through the beam splitter and circulates therein along a delay loop length defined by the mirrors. As the laser beam pulse circulates within the delay loop a portion thereof is emitted upon each completed circuit when the laser beam pulse strikes the beam splitter. The laser beam pulse is thereby formatted into a plurality of sub-pulses. The delay loops are used in combination to produce complex waveforms by combining the sub-pulses using additive waveform synthesis. 8 figs.

  3. Laser beam pulse formatting method

    DOEpatents

    Daly, Thomas P.; Moses, Edward I.; Patterson, Ralph W.; Sawicki, Richard H.

    1994-01-01

    A method for formatting a laser beam pulse (20) using one or more delay loops (10). The delay loops (10) have a partially reflective beam splitter (12) and a plurality of highly reflective mirrors (14) arranged such that the laser beam pulse (20) enters into the delay loop (10) through the beam splitter (12) and circulates therein along a delay loop length (24) defined by the mirrors (14). As the laser beam pulse (20) circulates within the delay loop (10) a portion thereof is emitted upon each completed circuit when the laser beam pulse (20) strikes the beam splitter (12). The laser beam pulse (20) is thereby formatted into a plurality of sub-pulses (50, 52, 54 and 56). The delay loops (10) are used in combination to produce complex waveforms by combining the sub-pulses (50, 52, 54 and 56) using additive waveform synthesis.

  4. Formation of Ultracold Polar Molecules

    NASA Astrophysics Data System (ADS)

    Taylor-Juarros, E.; Côté, R.; Kirby, K.

    2002-05-01

    A variety of experimental techniques have been employed to create a number of ultracold molecules, including CaH, Na_2, K_2, Cs_2, Rb2 and CO. Novel effects are predicted to occur in samples of ultracold polar molecules.(L. Santos et al.), Phys. Rev. Lett. 85, 1791 (2000). We present calculations of the formation rate of ultracold hydrides (LiH, NaH, KH, RbH, and CsH), using the most accurate molecular potentials and dipole moments available. We show that these polar molecules can be produced in selected vibrational and rotational states by stimulated radiative association in a mixture of ultracold hydrogen and alkali metal atoms. We study the properties of these atomic mixtures as well as those of the hydrides, and explore the effect of shape resonances on the formation rates. [2ex] *Supported by NSF

  5. Formation of quasiparallel Alfven solitons

    NASA Technical Reports Server (NTRS)

    Hamilton, R. L.; Kennel, C. F.; Mjolhus, E.

    1992-01-01

    The formation of quasi-parallel Alfven solitons is investigated through the inverse scattering transformation (IST) for the derivative nonlinear Schroedinger (DNLS) equation. The DNLS has a rich complement of soliton solutions consisting of a two-parameter soliton family and a one-parameter bright/dark soliton family. In this paper, the physical roles and origins of these soliton families are inferred through an analytic study of the scattering data generated by the IST for a set of initial profiles. The DNLS equation has as limiting forms the nonlinear Schroedinger (NLS), Korteweg-de-Vries (KdV) and modified Korteweg-de-Vries (MKdV) equations. Each of these limits is briefly reviewed in the physical context of quasi-parallel Alfven waves. The existence of these limiting forms serves as a natural framework for discussing the formation of Alfven solitons.

  6. The dynamics of city formation*

    PubMed Central

    Henderson, J. Vernon; Venables, Anthony J.

    2013-01-01

    This paper examines city formation in a country whose urban population is growing steadily over time, with new cities required to accommodate this growth. In contrast to most of the literature there is immobility of housing and urban infrastructure, and investment in these assets is taken on the basis of forward-looking behavior. In the presence of these fixed assets cities form sequentially, without the population swings in existing cities that arise in current models, but with swings in house rents. Equilibrium city size, absent government, may be larger or smaller than is efficient, depending on how urban externalities vary with population. Efficient formation of cities with internalization of externalities involves local government intervention and borrowing to finance development. The paper explores the institutions required for successful local government intervention. PMID:25089087

  7. Hydrogen Sulfide Inhibits Amyloid Formation

    PubMed Central

    2015-01-01

    Amyloid fibrils are large aggregates of misfolded proteins, which are often associated with various neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s, and vascular dementia. The amount of hydrogen sulfide (H2S) is known to be significantly reduced in the brain tissue of people diagnosed with Alzheimer’s disease relative to that of healthy individuals. These findings prompted us to investigate the effects of H2S on the formation of amyloids in vitro using a model fibrillogenic protein hen egg white lysozyme (HEWL). HEWL forms typical β-sheet rich fibrils during the course of 70 min at low pH and high temperatures. The addition of H2S completely inhibits the formation of β-sheet and amyloid fibrils, as revealed by deep UV resonance Raman (DUVRR) spectroscopy and ThT fluorescence. Nonresonance Raman spectroscopy shows that disulfide bonds undergo significant rearrangements in the presence of H2S. Raman bands corresponding to disulfide (RSSR) vibrational modes in the 550–500 cm–1 spectral range decrease in intensity and are accompanied by the appearance of a new 490 cm–1 band assigned to the trisulfide group (RSSSR) based on the comparison with model compounds. The formation of RSSSR was proven further using a reaction with TCEP reduction agent and LC-MS analysis of the products. Intrinsic tryptophan fluorescence study shows a strong denaturation of HEWL containing trisulfide bonds. The presented evidence indicates that H2S causes the formation of trisulfide bridges, which destabilizes HEWL structure, preventing protein fibrillation. As a result, small spherical aggregates of unordered protein form, which exhibit no cytotoxicity by contrast with HEWL fibrils. PMID:25545790

  8. THE BLACK HOLE FORMATION PROBABILITY

    SciTech Connect

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P {sub BH}(M {sub ZAMS}). Although we find that it is difficult to derive a unique P {sub BH}(M {sub ZAMS}) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P {sub BH}(M {sub ZAMS}) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P {sub BH}(M {sub ZAMS}) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  9. The Black Hole Formation Probability

    NASA Astrophysics Data System (ADS)

    Clausen, Drew; Piro, Anthony L.; Ott, Christian D.

    2015-02-01

    A longstanding question in stellar evolution is which massive stars produce black holes (BHs) rather than neutron stars (NSs) upon death. It has been common practice to assume that a given zero-age main sequence (ZAMS) mass star (and perhaps a given metallicity) simply produces either an NS or a BH, but this fails to account for a myriad of other variables that may effect this outcome, such as spin, binarity, or even stochastic differences in the stellar structure near core collapse. We argue that instead a probabilistic description of NS versus BH formation may be better suited to account for the current uncertainties in understanding how massive stars die. We present an initial exploration of the probability that a star will make a BH as a function of its ZAMS mass, P BH(M ZAMS). Although we find that it is difficult to derive a unique P BH(M ZAMS) using current measurements of both the BH mass distribution and the degree of chemical enrichment by massive stars, we demonstrate how P BH(M ZAMS) changes with these various observational and theoretical uncertainties. We anticipate that future studies of Galactic BHs and theoretical studies of core collapse will refine P BH(M ZAMS) and argue that this framework is an important new step toward better understanding BH formation. A probabilistic description of BH formation will be useful as input for future population synthesis studies that are interested in the formation of X-ray binaries, the nature and event rate of gravitational wave sources, and answering questions about chemical enrichment.

  10. Method for fracturing subterranean formations

    SciTech Connect

    Almond, S. W.; Conway, M. W.

    1985-11-19

    The present invention relates to a thermally stable crosslinked gel fracturing fluid for use in the treatment of subterranean formations penetrated by a well bore. The fracturing fluid comprises an aqueous liquid, a gelling agent comprising a selected modified cellulose ether, a crosslinking agent and any additional additives that may be present. The fracturing fluid is thermally stable under shear at temperatures in excess of about 200/sup 0/ F.

  11. Memory Formation Shaped by Astroglia

    PubMed Central

    Zorec, Robert; Horvat, Anemari; Vardjan, Nina; Verkhratsky, Alexei

    2015-01-01

    Astrocytes, the most heterogeneous glial cells in the central nervous system (CNS), execute a multitude of homeostatic functions and contribute to memory formation. Consolidation of synaptic and systemic memory is a prolonged process and hours are required to form long-term memory. In the past, neurons or their parts have been considered to be the exclusive cellular sites of these processes, however, it has now become evident that astrocytes provide an important and essential contribution to memory formation. Astrocytes participate in the morphological remodeling associated with synaptic plasticity, an energy-demanding process that requires mobilization of glycogen, which, in the CNS, is almost exclusively stored in astrocytes. Synaptic remodeling also involves bidirectional astroglial-neuronal communication supported by astroglial receptors and release of gliosignaling molecules. Astroglia exhibit cytoplasmic excitability that engages second messengers, such as Ca2+, for phasic, and cyclic adenosine monophosphate (cAMP), for tonic signal coordination with neuronal processes. The detection of signals by astrocytes and the release of gliosignaling molecules, in particular by vesicle-based mechanisms, occurs with a significant delay after stimulation, orders of magnitude longer than that present in stimulus–secretion coupling in neurons. These particular arrangements position astrocytes as integrators ideally tuned to support time-dependent memory formation. PMID:26635551

  12. NSDF: Neuroscience Simulation Data Format.

    PubMed

    Ray, Subhasis; Chintaluri, Chaitanya; Bhalla, Upinder S; Wójcik, Daniel K

    2016-04-01

    Data interchange is emerging as an essential aspect of modern neuroscience. In the areas of computational neuroscience and systems biology there are multiple model definition formats, which have contributed strongly to the development of an ecosystem of simulation and analysis tools. Here we report the development of the Neuroscience Simulation Data Format (NSDF) which extends this ecosystem to the data generated in simulations. NSDF is designed to store simulator output across scales: from multiscale chemical and electrical signaling models, to detailed single-neuron and network models, to abstract neural nets. It is self-documenting, efficient, modular, and scalable, both in terms of novel data types and in terms of data volume. NSDF is simulator-independent, and can be used by a range of standalone analysis and visualization tools. It may also be used to store variety of experimental data. NSDF is based on the widely used HDF5 (Hierarchical Data Format 5) specification and is open, platform-independent, and portable.

  13. Theory of Planetary System Formation

    NASA Technical Reports Server (NTRS)

    Cassen, Patrick

    1996-01-01

    Observations and theoretical considerations support the idea that the Solar System formed by the collapse of tenuous interstellar matter to a disk of gas and dust (the primitive solar nebula), from which the Sun and other components separated under the action of dissipative forces and by the coagulation of solid material. Thus, planets are understood to be contemporaneous byproducts of star formation. Because the circumstellar disks of new stars are easier to observe than mature planetary systems, the possibility arises that the nature and variety of planets might be studied from observations of the conditions of their birth. A useful theory of planetary system formation would therefore relate the properties of circumstellar disks both to the initial conditions of star formation and to the consequent properties of planets to those of the disk. Although the broad outlines of such a theory are in place, many aspects are either untested, controversial, or otherwise unresolved; even the degree to which such a comprehensive theory is possible remains unknown.

  14. The formation of star clusters

    NASA Astrophysics Data System (ADS)

    Whitmore, Bradley C.

    The ability of HST to resolve objects ten times smaller than possible from the ground has re-juvenated the study of young star clusters. A recurrent morphological theme found in nearby resolved systems is the observation of young (typically 1-10 Myr), massive (103 - 104 Msolar), compact (ρ≍105 Msolar pc-3) clusters which have evacuated the gas and dust from a spherical region around themselves. New stars are being triggered into formation along the edges of the envelopes, with pillars (similar to the Eagle Nebula) of molecular gas streaming away from the regions of star formation. The prototype for these objects is 30 Doradus. Another major theme has been the discovery of large numbers of young (typically 1-500 Myr), massive (103 - 108 Msolar), compact star clusters in merging, starbursting, and even some barred and spiral galaxies. The brightest of these clusters have all the attributes expected of protoglobular clusters, hence allowing us to study the formation of globular clusters in the local universe rather than trying to ascertain how they formed ≍14 Gyr ago. The prototype is the Antennae Galaxy.

  15. SCALE FORMATION IN CHRYSOPHYCEAN ALGAE

    PubMed Central

    Brown, R. Malcolm; Franke, Werner W.; Kleinig, Hans; Falk, Heinz; Sitte, Peter

    1970-01-01

    The cell wall of the marine chrysophycean alga Pleurochrysis scherfellii is composed of distinct wall fragments embedded in a gelatinous mass. The latter is a polysaccharide of pectic character which is rich in galactose and ribose. These wall fragments are identified as scales. They have been isolated and purified from the vegetative mother cell walls after zoospore formation. Their ultrastructure is described in an electron microscope study combining sectioning, freeze-etch, and negative staining techniques. The scales consist of a layer of concentrically arranged microfibrils (ribbons with cross-sections of 12 to 25 x 25 to 40 A) and underlying radial fibrils of similar dimensions. Such a network-plate is densely coated with particles which are assumed to be identical to the pectic component. The microfibrils are resistant to strong alkaline treatment and have been identified as cellulose by different methods, including sugar analysis after total hydrolysis, proton resonance spectroscopical examination (NMR spectroscopy) of the benzoylated product, and diverse histochemical tests. The formation and secretion of the scales can be followed along the maturing Golgi cisternae starting from a pronounced dilated "polymerization center" as a completely intracisternal process which ends in the exocytotic extrusion of the scales. The scales reveal the very same ultrastructure within the Golgi cisternae as they do in the cell wall. The present finding represents the first evidence on cellulose formation by the Golgi apparatus and is discussed in relation to a basic scheme for cellulose synthesis in plant cells in general. PMID:5513606

  16. Modeling of Dynamic FRC Formation

    NASA Astrophysics Data System (ADS)

    Mok, Yung; Barnes, Dan; Dettrick, Sean

    2010-11-01

    We have developed a 2-D resistive MHD code, Lamy Ridge, to simulate the entire FRC formation process in Tri Alpha's C2 device, including initial formation, translation, merging and settling into equilibrium. Two FRC's can be created simultaneously, and then translated toward each other so that they merge into a single FRC. The code couples the external circuits around the formation tubes to the partially ionized plasma inside. Plasma and neutral gas are treated as two fluids. Dynamic and energetic equations, which take into account ionization and charge exchange, are solved in a time advance manner. The geometric shape of the vessel is specified by a set of inputs that defines the boundaries, which are handled by a cut-cell algorithm in the code. Multiple external circuits and field coils can be easily added, removed or relocated through individual inputs. The design of the code is modular and flexible so that it can be applied to future devices. The results of the code are in reasonable agreement with experimental measurements on the C2 device.

  17. Supernova Feedback in Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Dubois, Y.; Teyssier, R.

    2008-06-01

    The hierarchical model of galaxy formation is known to suffer from the ``over-cooling'' problem: the high efficiency of radiative cooling results in too much baryonic matter in a condensed phase (namely, cold gas or stars) when compared to observations. A solution proposed by many authors (see Springel & Hernquist 2003; Fujita et al. 2004; Rasera & Teyssier 2005) is feedback due to supernova (SN) driven winds or active galactic nuclei. Modeling SN feedback by direct injection of thermal energy usually turns out to be inefficient in galaxy-scale simulations, due to the quasi-instantaneous radiation of the SN energy. To avoid this effect, we have developed a new method to incorporate SN feedback in cosmological simulations: using temporary test particles, we reproduce explicitly a local Sedov blast wave solution in the gas distribution. We have performed several self-consistent runs of isolated Navarro, Frenk, & White (1996, hereafter NFW) halos with radiative cooling, star formation, SN feedback and metal enrichment using the adaptive mesh refinement code RAMSES (Teyssier 2002). We have explored the influence of SN feedback on the formation and the evolution of galaxies with different masses. We have studied the efficiency of the resulting galactic winds, as a function of the mass of the parent halo.

  18. Illusory contour formation survives crowding.

    PubMed

    Lau, Jonathan Siu Fung; Cheung, Sing-Hang

    2012-06-12

    Flanked objects are difficult to identify using peripheral vision due to visual crowding, which limits conscious access to target identity. Nonetheless, certain types of visual information have been shown to survive crowding. Such resilience to crowding provides valuable information about the underlying neural mechanism of crowding. Here we ask whether illusory contour formation survives crowding of the inducers. We manipulated the presence of illusory contours through the (mis)alignment of the four inducers of a Kanizsa square. In the inducer-aligned condition, the observers judged the perceived shape (thin vs. fat) of the illusory Kanizsa square, manipulated by small rotations of the inducers. In the inducer-misaligned condition, three of the four inducers (all except the upper-left) were rotated 90°. The observers judged the orientation of the upper-left inducer. Crowding of the inducers worsened observers' performance significantly only in the inducer-misaligned condition. Our findings suggest that information for illusory contour formation survives crowding of the inducers. Crowding happens at a stage where the low-level featural information is integrated for inducer orientation discrimination, but not at a stage where the same information is used for illusory contour formation.

  19. NSDF: Neuroscience Simulation Data Format.

    PubMed

    Ray, Subhasis; Chintaluri, Chaitanya; Bhalla, Upinder S; Wójcik, Daniel K

    2016-04-01

    Data interchange is emerging as an essential aspect of modern neuroscience. In the areas of computational neuroscience and systems biology there are multiple model definition formats, which have contributed strongly to the development of an ecosystem of simulation and analysis tools. Here we report the development of the Neuroscience Simulation Data Format (NSDF) which extends this ecosystem to the data generated in simulations. NSDF is designed to store simulator output across scales: from multiscale chemical and electrical signaling models, to detailed single-neuron and network models, to abstract neural nets. It is self-documenting, efficient, modular, and scalable, both in terms of novel data types and in terms of data volume. NSDF is simulator-independent, and can be used by a range of standalone analysis and visualization tools. It may also be used to store variety of experimental data. NSDF is based on the widely used HDF5 (Hierarchical Data Format 5) specification and is open, platform-independent, and portable. PMID:26585711

  20. Theory of Remote Image Formation

    NASA Astrophysics Data System (ADS)

    Blahut, Richard E.

    2004-11-01

    In many applications, images, such as ultrasonic or X-ray signals, are recorded and then analyzed with digital or optical processors in order to extract information. Such processing requires the development of algorithms of great precision and sophistication. This book presents a unified treatment of the mathematical methods that underpin the various algorithms used in remote image formation. The author begins with a review of transform and filter theory. He then discusses two- and three-dimensional Fourier transform theory, the ambiguity function, image construction and reconstruction, tomography, baseband surveillance systems, and passive systems (where the signal source might be an earthquake or a galaxy). Information-theoretic methods in image formation are also covered, as are phase errors and phase noise. Throughout the book, practical applications illustrate theoretical concepts, and there are many homework problems. The book is aimed at graduate students of electrical engineering and computer science, and practitioners in industry. Presents a unified treatment of the mathematical methods that underpin the algorithms used in remote image formation Illustrates theoretical concepts with reference to practical applications Provides insights into the design parameters of real systems