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Sample records for rapid fluvial incision

  1. Rapid fluvial incision of a late Holocene lava flow: Insights from LiDAR, alluvial stratigraphy, and numerical modeling

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    Sweeney, Kristin; Roering, Joshua J.

    2016-01-01

    Volcanic eruptions fundamentally alter landscapes, paving over channels, decimating biota, and emplacing fresh, unweathered material. The fluvial incision of blocky lava flows is a geomorphic puzzle. First, high surface permeability and lack of sediment should preclude geomorphically effective surface runoff and dissection. Furthermore, past work has demonstrated the importance of extreme floods in driving incision via column toppling and plucking in columnar basalt, but it is unclear how incision occurs in systems where surface blocks are readily mobile. We examine rapid fluvial incision of the Collier lava flow, an andesitic Holocene lava flow in the High Cascades of Oregon. Since lava flow emplacement ∼1600 yr ago, White Branch Creek has incised bedrock gorges up to 8 m deep into the coherent core of the lava flow and deposited >0.2 km3 of sediment on the lava flow surface. Field observation points to a bimodal discharge regime in the channel, with evidence for both annual snowmelt runoff and outburst floods from Collier glacier, as well as historical evidence of vigorous glacial meltwater. To determine the range of discharge events capable of incision in White Branch Creek, we used a mechanistic model of fluvial abrasion. We show that the observed incision implies that moderate flows are capable of both initiating channel formation and sustaining incision. Our results have implications for the evolution of volcanic systems worldwide, where glaciation and/or mass wasting may accelerate fluvial processes by providing large amounts of sediment to otherwise porous, sediment-starved landscapes.

  2. Signatures of Late Pleistocene fluvial incision in an Alpine landscape

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    Leith, Kerry; Fox, Matthew; Moore, Jeffrey R.

    2018-02-01

    Uncertainty regarding the relative efficacy of fluvial and glacial erosion has hindered attempts to quantitatively analyse the Pleistocene evolution of alpine landscapes. Here we show that the morphology of major tributaries of the Rhone River, Switzerland, is consistent with that predicted for a landscape shaped primarily by multiple phases of fluvial incision following a period of intense glacial erosion after the mid-Pleistocene transition (∼0.7 Ma). This is despite major ice sheets reoccupying the region during cold intervals since the mid-Pleistocene. We use high-resolution LiDAR data to identify a series of convex reaches within the long-profiles of 18 tributary channels. We propose these reaches represent knickpoints, which developed as regional uplift raised tributary bedrock channels above the local fluvial baselevel during glacial intervals, and migrated upstream as the fluvial system was re-established during interglacial periods. Using a combination of integral long-profile analysis and stream-power modelling, we find that the locations of ∼80% of knickpoints in our study region are consistent with that predicted for a fluvial origin, while the mean residual error over ∼100 km of modelled channels is just 26.3 m. Breaks in cross-valley profiles project toward the elevation of former end-of-interglacial channel elevations, supporting our model results. Calculated long-term uplift rates are within ∼15% of present-day measurements, while modelled rates of bedrock incision range from ∼1 mm/yr for low gradient reaches between knickpoints to ∼6-10 mm/yr close to retreating knickpoints, typical of observed rates in alpine settings. Together, our results reveal approximately 800 m of regional uplift, river incision, and hillslope erosion in the lower half of each tributary catchment since 0.7 Ma.

  3. What can we learn from fluvial incision in high mountains?

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    Fuchs, Margret; Gloaguen, Richard; Krbetschek, Matthias

    2013-04-01

    High and actively deforming mountain ranges attract the attention of geoscientists as they provide natural laboratories of fast evolving process-response systems. Tectonic compressional settings, often linked to perpendicular extension, control the topographic growth and hence, erosion, transport pathways and sedimentation. High altitude differences within short horizontal distances promote material re-organisation and high rates of surface processes. Furthermore, high mountains constitute orographic barriers that affect atmospheric circulations as well as host different climate regimes similar to those of widely separated latitudinal belts. Both cause a high sensitivity of surface processes to changes in climatic conditions. However, feedbacks between climatic and tectonic forcing are complex. Additionally, the dominance of one or the other varies in space and also over time, inheriting various traces of the paleo-morphodynamic conditions to the subsequent process regimes. To unravel the forces driving the evolution of relief in active mountains, numerous studies employ the drainage network of the corresponding mountains as a proxy of landscape evolution. Especially the rates of river incision provide a powerful tool to characterize the surface response and infer causes behind it. Several parameters of river incision are available to describe the fluvial incision at individual sites (e.g. terrace incision rates), along the river course (e.g. longitudinal river profiles, Hack index) and in its perpendicular dimension (e.g. valley cross sections, valley shape ratios). But they require careful interpretation. They are sensitive to both, climatic and tectonic forcing. Therefore, the synopsis of such indices for fluvial incision is essential to evaluate the role of climatic versus tectonic forcing. Here, we use the Panj river system, the major river draining the Pamir mountains of Central Asia, as an example. The Panj experiences high altitude changes of more than 4000

  4. Climate-sensitive feedbacks between hillslope processes and fluvial erosion in sediment-driven incision models

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    Skov, Daniel S.; Egholm, David L.

    2016-04-01

    Surface erosion and sediment production seem to have accelerated globally as climate cooled in the Late Cenozoic, [Molnar, P. 2004, Herman et al 2013]. Glaciers emerged in many high mountain ranges during the Quaternary, and glaciation therefore represents a likely explanation for faster erosion in such places. Still, observations and measurements point to increases in erosion rates also in landscapes where erosion is driven mainly by fluvial processes [Lease and Ehlers (2013), Reusser (2004)]. Flume experiments and fieldwork have shown that rates of incision are to a large degree controlled by the sediment load of streams [e.g. Sklar and Dietrich (2001), Beer and Turowski (2015)]. This realization led to the formulation of sediment-flux dependent incision models [Sklar and Dietrich (2004)]. The sediment-flux dependence links incision in the channels to hillslope processes that supply sediment to the channels. The rates of weathering and soil transport on the hillslopes are processes that are likely to respond to changing temperatures, e.g. because of vegetation changes or the occurrence of frost. In this study, we perform computational landscape evolution experiments, where the coupling between fluvial incision and hillslope processes is accounted for by coupling a sediment-flux-dependent model for fluvial incision to a climate-dependent model for weathering and hillslope sediment transport. The computational experiments first of all demonstrate a strong positive feedback between channel and hillslope processes. In general, faster weathering leads to higher rates of channel incision, which further increases the weathering rates, mainly because of hillslope steepening. Slower weathering leads to the opposite result. The experiments also demonstrate, however, that the feedbacks vary significantly between different parts of a drainage network. For example, increasing hillslope sediment production may accelerate incision in the upper parts of the catchment, while at

  5. Modeling Long-Term Fluvial Incision : Shall we Care for the Details of Short-Term Fluvial Dynamics?

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    Lague, D.; Davy, P.

    2008-12-01

    Fluvial incision laws used in numerical models of coupled climate, erosion and tectonics systems are mainly based on the family of stream power laws for which the rate of local erosion E is a power function of the topographic slope S and the local mean discharge Q : E = K Qm Sn. The exponents m and n are generally taken as (0.35, 0.7) or (0.5, 1), and K is chosen such that the predicted topographic elevation given the prevailing rates of precipitation and tectonics stay within realistic values. The resulting topographies are reasonably realistic, and the coupled system dynamics behaves somehow as expected : more precipitation induces increased erosion and localization of the deformation. Yet, if we now focus on smaller scale fluvial dynamics (the reach scale), recent advances have suggested that discharge variability, channel width dynamics or sediment flux effects may play a significant role in controlling incision rates. These are not factored in the simple stream power law model. In this work, we study how these short- term details propagate into long-term incision dynamics within the framework of surface/tectonics coupled numerical models. To upscale the short term dynamics to geological timescales, we use a numerical model of a trapezoidal river in which vertical and lateral incision processes are computed from fluid shear stress at a daily timescale, sediment transport and protection effects are factored in, as well as a variable discharge. We show that the stream power law model might still be a valid model but that as soon as realistic effects are included such as a threshold for sediment transport, variable discharge and dynamic width the resulting exponents m and n can be as high as 2 and 4. This high non-linearity has a profound consequence on the sensitivity of fluvial relief to incision rate. We also show that additional complexity does not systematically translates into more non-linear behaviour. For instance, considering only a dynamical width

  6. A Precise 6 Ma Start Date for Fluvial Incision of the Northeastern Colorado Plateau Canyonlands

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    Thomson, S. N.; Soreghan, G. S.; Reiners, P. W.; Peyton, S. L.; Murray, K. E.

    2015-12-01

    Outstanding questions regarding late Cenozoic Colorado Plateau landscape evolution include: (1) the relative roles of isostatic rebound as result Colorado River incision versus longer-term geodynamic processes in driving overall rock uplift of the plateau; and (2) whether incision was triggered by river integration or by a change in deep-seated mantle lithosphere dynamics. A key to answering these questions is to date more precisely the onset of incision to refine previous estimates of between 6 and 10 Ma. We present new low-temperature thermochronologic results from bedrock and deep borehole samples in the northeastern Colorado Plateau to show that rapid river incision began here at 6 Ma (5.93±0.66 Ma) with incision rates increasing from 15-50 m/Myr to 160-200 m/Myr. The onset time is constrained independently by both inverse time-temperature modeling and by the break-in-slope in fission track age-elevation relationships. This new time constraint has several important implications. First, the coincidence in time with 5.97-5.3 Ma integration of the lower Colorado River through the Grand Canyon to the Gulf of California strongly favors downstream river integration triggering carving of the canyonlands of the upper Colorado River system. Second, it implies integration of the entire Colorado River system in less than 2 million years. Third, rock uplift of the plateau driven by the flexural isostatic response to river incision is restricted to just the last 6 Ma, as is associated increased sediment budget. Fourth, incision starting at 6 Ma means that previous estimates of upper Colorado River incision rates based on 10-12 Ma basalt datum levels are too low. This also changes the dependency of measured time interval on incision rate from a non-steady-state negative power-law dependence (exponent of -0.24) to a near steady-state dependence (exponent of 0.07) meaning that long-term upper Colorado river incision rates can provide a reliable proxy for rock uplift rates.

  7. Middel Pleistocene to Holocene fluvial terrace development and uplift-driven valley incision in the SE Carpathians, Romania

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    Necea, D.; Fielitz, W.; Andriessen, P.A.M.; Dinu, C.

    2013-01-01

    This study reveals that in the SE Carpathians terrace development and fluvial incision during the Middle Pleistocene-Holocene are predominantly controlled by tectonic uplift as shown by terrace distributions and uplift amounts and rates. The work focuses on a transect from the internal nappes and

  8. Incision of the Jezero Crater Outflow Channel by Fluvial Sediment Transport

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    Holo, S.; Kite, E. S.

    2017-12-01

    Jezero crater, the top candidate landing site for the Mars 2020 rover, once possessed a lake that over-spilled and eroded a large outflow channel into the Eastern rim. The Western deltaic sediments that would be the primary science target of the rover record a history of lake level, which is modulated by the inflow and outflow channels. While formative discharges for the Western delta exist ( 500 m3/s), little work has been done to see if these flows are the same responsible for outflow channel incision. Other models of the Jezero outflow channel incision assume that a single rapid flood (incision timescales of weeks), with unknown initial hydraulic head and no discharge into the lake (e.g. from the inflow channels or the subsurface), incised an open channel with discharge modulated by flow over a weir. We present an alternate model where, due to an instability at the threshold of sediment motion, the incision of the outflow channel occurs in concert with lake filling. In particular, we assume a simplified lake-channel-valley system geometry and that the channel is hydraulically connected to the filling/draining crater lake. Bed load sediment transport and water discharge through the channel are quantified using the Meyer-Peter and Mueller relation and Manning's law respectively. Mass is conserved for both water and sediment as the lake level rises/falls and the channel incises. This model does not resolve backwater effects or concavity in the alluvial system, but it does capture the non-linear feedbacks between lake draining, erosion rate, channel flow rate, and slope relaxation. We identify controls on incision of the outflow channel and estimate the time scale of outflow channel formation through a simple dynamical model. We find that the observed 300m of channel erosion can be reproduced in decades to centuries of progressive bed load as the delta forming flows fill the lake. This corresponds to time scales on the order of or smaller than the time scale

  9. Tidal Simulations of an Incised-Valley Fluvial System with a Physics-Based Geologic Model

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    Ghayour, K.; Sun, T.

    2012-12-01

    Physics-based geologic modeling approaches use fluid flow in conjunction with sediment transport and deposition models to devise evolutionary geologic models that focus on underlying physical processes and attempt to resolve them at pertinent spatial and temporal scales. Physics-based models are particularly useful when the evolution of a depositional system is driven by the interplay of autogenic processes and their response to allogenic controls. This interplay can potentially create complex reservoir architectures with high permeability sedimentary bodies bounded by a hierarchy of shales that can effectively impede flow in the subsurface. The complex stratigraphy of tide-influenced fluvial systems is an example of such co-existing and interacting environments of deposition. The focus of this talk is a novel formulation of boundary conditions for hydrodynamics-driven models of sedimentary systems. In tidal simulations, a time-accurate boundary treatment is essential for proper imposition of tidal forcing and fluvial inlet conditions where the flow may be reversed at times within a tidal cycle. As such, the boundary treatment at the inlet has to accommodate for a smooth transition from inflow to outflow and vice-versa without creating numerical artifacts. Our numerical experimentations showed that boundary condition treatments based on a local (frozen) one-dimensional approach along the boundary normal which does not account for the variation of flow quantities in the tangential direction often lead to unsatisfactory results corrupted by numerical artifacts. In this talk, we propose a new boundary treatment that retains all spatial and temporal terms in the model and as such is capable to account for nonlinearities and sharp variations of model variables near boundaries. The proposed approach borrows heavily from the idea set forth by J. Sesterhenn1 for compressible Navier-Stokes equations. The methodology is successfully applied to a tide-influenced incised

  10. Fluvial incision by the Qingyijiang River on the northern fringe of Mt. Huangshan, eastern China: Responses to weakening of the East Asian summer monsoon

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    Hu, Chunsheng; Liu, Shaochen; Hu, Chenqi; Xu, Guanglai; Zhou, Yingqiu

    2017-12-01

    This paper focuses on climatic and tectonic controls to determine their relative importance to the Quaternary fluvial incision by the Qingyijiang River, eastern China. The Qingyijiang, which is one of longest tributaries of the lower Yangtze River, drains the northern piedmont of Mt. Huangshan. A field survey focused on three natural sections of the Qingyijiang in the Jingxian basin, where a well-preserved sequence of one alluvial platform (P) and three fluvial terraces (T3, T2, and T1) is presented. The heights of the platform and the terraces above river level are 65, 40, 20, and 7 m respectively. In this study, electron spin resonance (ESR), optical stimulated luminescence (OSL), and palaeomagnetic dating were applied to reconstruct the fluvial incision history of the Qingyijiang and evaluate the possible influence of tectonic uplift and/or climate change on the fluvial incision. The main results show that (1) the ages of P, T3, T2, and T1 were determined to be ∼ 1300, ∼ 900, ∼ 600, and ∼ 1.5 ka respectively, corresponding to four incision events in the Qingyijiang; (2) the East Asian summer monsoon (EASM) experienced four significant weakening events at 1300, 900, 600, and ∼ 1.5 ka, according to previous research. Correspondingly, we propose that four significant increased periods of regional precipitation occurred at 1300, 900, 600, and ∼ 1.5 ka in the study area because of the negative correlation between the intensity of the EASM and regional precipitation from 1960 to 2012; and (3) fluvial incision by the Qingyijiang arose as a result of the weakening of the EASM in combination with tectonic uplift, determined by matching fluvial incision history of the Qingyijiang with tectonic movement and EASM change. In addition, the weakening of the EASM climatically triggered fluvial incision by the Qingyijiang. This study supports the conclusion that major fluvial incision has been climatically triggered; however, it also suggests that the mechanism of

  11. External controls on Quaternary fluvial incision and terrace formation at the Segre River, Southern Pyrenees

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    Stange, K.M.; van Balen, R.T.; Vandenberghe, J.; Peña, J.L.; Sancho, C.

    2013-01-01

    Focusing on climatic- and structural (tectonic) controls, we aim to determine their relative importance for the (Pliocene to Quaternary) fluvial landscape evolution in the Southern Pyrenees foreland. We investigate the Segre River, which is one of the major streams of the Southern Pyrenees that

  12. Valley-scale morphology drives differences in fluvial sediment budgets and incision rates during contrasting flow regimes

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    Weber, M. D.; Pasternack, G. B.

    2017-07-01

    High-resolution topographic surveys using LiDAR and multibeam sonar can be used to characterize and quantify fluvial change. This study used repeat surveys to explore how topographic change, fluvial processes, sediment budgets, and aggradation and incision rates vary across spatial scales and across two contrasting decadal flow regimes in a regulated gravel/cobble river. A novel method for quantifying digital elevation model uncertainty was developed and applied to a topographic change detection analysis from 2006/2008 to 2014. During this period, which had four modest 3-5 year floods, most sediment was laterally redistributed through bank erosion and channel migration. Erosion primarily occurred in the floodplain (97,000 m3), terraces (80,000 m3), and lateral bars (58,000 m3); while deposition occurred in the adjacent pools (73,000 m3), fast glides (48,000 m3), and runs (36,000 m3). In contrast, significantly higher magnitude and longer duration floods from 1999 to 2006/2008 caused sediment to be displaced longitudinally, with the upstream reaches exporting sediment and the downstream reaches aggrading. The river maintained floodplain connectivity during both periods, despite different processes dominating the type of connectivity. Larger floods promoted overbank scour and avulsion, while smaller floods promoted bank erosion and lateral migration. This study explores and illustrates how the geomorphic response to contrasting flood regimes in a nonuniform river is highly dependent on which landforms are controlling hydraulics.

  13. Significance of Thermal Fluvial Incision and Bedrock Transfer due to Ice Advection on Greenland Ice Sheet Topography

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    Crozier, J. A.; Karlstrom, L.; Yang, K.

    2017-12-01

    Ice sheet surface topography reflects a complicated combination of processes that act directly upon the surface and that are products of ice advection. Using recently-available high resolution ice velocity, imagery, ice surface elevation, and bedrock elevation data sets, we seek to determine the domain of significance of two important processes - thermal fluvial incision and transfer of bedrock topography through the ice sheet - on controlling surface topography in the ablation zone. Evaluating such controls is important for understanding how melting of the GIS surface during the melt season may be directly imprinted in topography through supraglacial drainage networks, and indirectly imprinted through its contribution to basal sliding that affects bedrock transfer. We use methods developed by (Karlstrom and Yang, 2016) to identify supraglacial stream networks on the GIS, and use high resolution surface digital elevation models as well as gridded ice velocity and melt rate models to quantify surface processes. We implement a numerically efficient Fourier domain bedrock transfer function (Gudmundsson, 2003) to predict surface topography due to ice advection over bedrock topography obtained from radar. Despite a number of simplifying assumptions, the bedrock transfer function predicts the observed ice sheet surface in most regions of the GIS with ˜90% accuracy, regardless of the presence or absence of supraglacial drainage networks. This supports the hypothesis that bedrock is the most significant driver of ice surface topography on wavelengths similar to ice thickness. Ice surface topographic asymmetry on the GIS is common, with slopes in the direction of ice flow steeper than those faced opposite to ice flow, consistent with bedrock transfer theory. At smaller wavelengths, topography consistent with fluvial erosion by surface hydrologic features is evident. We quantify the effect of ice advection versus fluvial thermal erosion on supraglacial longitudinal stream

  14. Rapid fluvial aggradation in response to climate change in northwestern Argentina

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    Wickert, Andrew; Schildgen, Taylor; Strecker, Manfred

    2015-04-01

    River channels near the edge of the northwestern Argentine Andes are rapidly aggrading at present, with preliminary estimates suggesting rates of ~20 cm yr-1. This mirrors cycles of extensive aggradation over the past 100,000 years that formed pronounced fill terraces along regional valley networks and record periods in which in which climate-driven sediment supply overcame uplift-driven river incision (Robinson et al, 2005). Here we use the new SedFlow model (Heimann et al., 2014) to help us understand the causes and spread of aggradation across these basins in the modern system, with the additional eventual goal to better interpret the geologic record. We provide field-derived grain-size distributions, field-measured and remotely-sensed channel widths and valley slopes, and a variety of possible sediment source locations and amounts as inputs to SedFlow, which routes sediment through the fluvial channel network to produce time-evolving predictions of aggradation and incision. We compare these predictions against changes in topography measured by IceSAT (Zwally et al., 2014) and field surveys. We initially test the system response to a series of isolated sediment inputs to observe interactions between tributary systems and the mainstem river. Recent observations indicate that debris-flow induced landslides are important contributors to aggradation in these rivers (Cencetti and Rivelli, 2011). These and other sediment production and transport processes are likely driven by variations in the El Niño Southern Oscillation (ENSO) (Bookhagen and Strecker, 2009). Therefore, we then run SedFlow with sediment inputs distributed across the landscape based on locations where ENSO influences may trigger enhanced landsliding. These model experiments help us towards our end goal of providing a more quantitative basis to interpret field observations of landscape response to changing patterns of precipitation. References: Bookhagen, B. and Strecker, M.: Amazonia: Landscape and

  15. Fluvial response to the last Holocene rapid climate change in the Northwestern Mediterranean coastlands

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    Degeai, Jean-Philippe; Devillers, Benoît; Blanchemanche, Philippe; Dezileau, Laurent; Oueslati, Hamza; Tillier, Margaux; Bohbot, Hervé

    2017-05-01

    The variability of fluvial activity in the Northwestern Mediterranean coastal lowlands and its relationship with modes of climate change were analysed from the late 9th to the 18th centuries CE. Geochemical analyses were undertaken from a lagoonal sequence and surrounding sediments in order to track the fluvial inputs into the lagoon. An index based on the K/S and Rb/S ratios was used to evidence the main periods of fluvial activity. This index reveals that the Medieval Climate Anomaly (MCA) was a drier period characterized by a lower fluvial activity, while the Little Ice Age (LIA) was a wetter period with an increase of the river dynamics. Three periods of higher than average fluvial activity were evidenced at the end of the first millennium CE (ca. 900-950 cal yr CE), in the first half of the second millennium CE (ca. 1150-1550 cal yr CE), and during the 1600s-1700s CE (ca. 1650-1800 cal yr CE). The comparison of these fluvial periods with other records of riverine or lacustrine floods in Spain, Italy, and South of France seems to indicate a general increase in fluvial and flood patterns in the Northwestern Mediterranean in response to the climate change from the MCA to the LIA, although some episodes of flooding are not found in all records. Besides, the phases of higher than average fluvial dynamics are in good agreement with the North Atlantic cold events evidenced from records of ice-rafted debris. The evolution of fluvial activity in the Northwestern Mediterranean coastlands during the last millennium could have been driven by atmospheric and oceanic circulation patterns.

  16. Unsteady Landscapes: Climatic and Tectonic Controls on Fluvial Terrace Formation

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    Clubb, F. J.; Mudd, S. M.

    2017-12-01

    Fluvial terraces are common landforms throughout mountainous regions which represent abandoned remnants of active river systems and their floodplains. The formation of these landforms points to a fundamental unsteadiness in the incision rate of the fluvial network, providing important information on channel response to climatic, tectonic, and base-level forcing, sediment storage and dynamics within mountainous systems, and the relative importance of lateral and vertical incision rates. In his 1877 Report on the Geology of the Henry Mountains, G.K. Gilbert suggested that strath terraces may form due to climatically-driven increase in sediment supply, causing armouring of the channel bed and hindering vertical incision. An alternative hypothesis suggests that strath terraces may be preserved through progressive tectonic uplift or base-level fall. These different formation mechanisms should result in varying distribution of terrace elevations along channels: if terraces are formed through climate-driven variations in sediment supply, we might expect that terrace elevations would be random, whereas progressive fluvial incision should result in a series of terraces with a systematic elevation pattern. Here we test alternative hypotheses for strath terrace formation using a new method for objectively and rapidly identifying terrace surfaces from digital elevation models (DEMs) over large spatial scales. Our new method identifies fluvial terraces using their gradient and elevation compared to the modern channel, thresholds of which are statistically calculated from the DEM and do not need to be set manually by the user. We use this method to extract fluvial terraces for every major river along the coast of California, and quantify their distribution and elevation along the fluvial long profile. Our results show that there is no systematic pattern in terrace elevations despite a well-constrained spatial variation in uplift rates, suggesting that terraces in this region do

  17. Rapid channel incision of the lower Pearl River (China since the 1990s as a consequence of sediment depletion

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    X. X. Lu

    2007-12-01

    Full Text Available This paper reported a dramatic channel incision (>10 m in the deepest cut during the past 10 y or so in the lower Pearl River, the second largest river in terms of water discharge in China. The channel incision had caused changes both in the channel geometry as well as in the river hydraulics. Also, the water exchange between the two major tributaries of the Pearl River, the Xijiang and Beijiang, had been significantly changed due to the channel incision. The rapid channel incision was principally the result of extensive sand mining in the lower Pearl River and the delta region due to the booming economy in the Pearl Delta region. Slight increase of water discharge and significant decrease of sediment load since the early 1990s in both the Xijiang and Beijiang also likely contributed to the observed dramatic river bed downcutting to some extent. This has important implications for river management, as the large Chinese rivers have seen a dramatic depletion of sediment fluxes due to the combined effects of declining rainfall, dam constructions, water diversion, reforestation and afforestation, and sediment mining over the recent decades.

  18. Evidence of anthropogenic tipping points in fluvial dynamics in Europe

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    Notebaert, Bastiaan; Broothaerts, Nils; Verstraeten, Gert

    2018-05-01

    In this study the occurrence of thresholds in fluvial style changes during the Holocene are discussed for three different catchments: the Dijle and Amblève catchments (Belgium) and the Valdaine Region (France). We consider tipping points to be a specific type of threshold, defined as relatively rapid and irreversible changes in the system. Field data demonstrate that fluvial style has varied in all three catchments over time, and that different tipping points can be identified. An increase in sediment load as a result of human induced soil erosion lead to a permanent change in the Dijle floodplains from a forested peaty marsh towards open landscape with clastic deposition and a well-defined river channel. In the Valdaine catchment, an increase in coarse sediment load, caused by increased erosion in the mountainous upper catchment, altered the floodplains from a meandering pattern to a braided pattern. Other changes in fluvial style appeared to be reversible. Rivers in the Valdaine were prone to different aggradation and incision phases due to changes in peak water discharge and sediment delivery, but the impact was too low for these changes to be irreversible. Likewise the Dijle River has recently be prone to an incision phase due to a clear water effect, and also this change is expected to be reversible. Finally, the Amblève River did not undergo major changes in style during the last 2000 to 5000 years, even though floodplain sedimentation rates increased tenfold during the last 600 years. Overall, these examples demonstrate how changes in fluvial style depend on the crossing of thresholds in sediment supply and water discharge. Although changes in these controlling parameters are caused by anthropogenic land use changes, the link between those land use changes and changes in fluvial style is not linear. This is due to the temporal variability in landscape connectivity and sediment transport and the non-linear relationship between land use intensity and soil

  19. Infilling and flooding of the Mekong River incised valley during deglacial sea-level rise

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    Tjallingii, Rik; Stattegger, Karl; Wetzel, Andreas; Van Phach, Phung

    2010-06-01

    The abrupt transition from fluvial to marine deposition of incised-valley-fill sediments retrieved from the southeast Vietnamese shelf, accurately records the postglacial transgression after 14 ka before present (BP). Valley-filling sediments consist of fluvial mud, whereas sedimentation after the transgression is characterized by shallow-marine carbonate sands. This change in sediment composition is accurately marked in high-resolution X-ray fluorescence (XRF) core scanning records. Rapid aggradation of fluvial sediments at the river mouth nearly completely filled the Mekong incised valley prior to flooding. However, accumulation rates strongly reduced in the valley after the river-mouth system flooded and stepped back. This also affected the sediment supply to deeper parts of the southeast Vietnamese shelf. Comparison of the Mekong valley-filling with the East Asian sea-level history of sub- and inter-tidal sediment records shows that the transgressive surface preserved in the incised-valley-fill records is a robust sea-level indicator. The valley was nearly completely filled with fluvial sediments between 13.0 and 9.5 ka BP when sea-level rose rather constantly with approximately 10 mm/yr, as indicated by the East Asian sea-level record. At shallower parts of the shelf, significant sediment reworking and the establishment of estuarine conditions at the final stage of infilling complicates accurate dating of the transgressive surface. Nevertheless, incised-valley-fill records and land-based drill sites indicate a vast and rapid flooding of the shelf from the location of the modern Vietnamese coastline to the Cambodian lowlands between 9.5 ka and 8.5 ka BP. Fast flooding of this part of the shelf is related with the low shelf gradient and a strong acceleration of the East Asian sea-level rise from 34 to 9 meter below modern sea level (mbsl) corresponding to the sea-level jump of melt water pulse (MWP) 1C.

  20. Recent, climate-driven river incision rate fluctuations in the Mercantour crystalline massif, southern French Alps

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    Petit, C.; Goren, L.; Rolland, Y.; Bourlès, D.; Braucher, R.; Saillard, M.; Cassol, D.

    2017-06-01

    We present a new geomorphological analysis of the Tinée River tributaries in the southern French Alps based on numerical inverse and forward modelling of their longitudinal profiles. We model their relative uplift history with respect to the main channel, hence the incision rate history of this channel. Inverse models show that all tributaries have consistent incision rate histories with alternating high and low values. A comparison with global temperature curves shows that these variations correlate with quaternary climate changes. We suggest that during warm periods, a wave of regressive erosion propagates in the Tinée River, while its tributaries deeply incise their substratum to catch up with the falling base-level. We also show that the post 140 ka history of this landscape evolution is dominated by fluvial incision. We then perform forward models of river incision and simulate the incision of the Tinée River system over a time span of 600 ka. This model allows us to extract time and space incision rate variations of the Tinée River. With a background of a few mm.yr-1, incision rate can increase up to more than 1 cm yr-1 during short periods of time due to climatic oscillations. This result is compatible with published cosmogenic nuclide based dating, which evidenced incision rates from 0.2 to 24 mm yr-1. The part of the channel located between 12 and 20 km downstream from the source has undergone several periods of rapid incision rates, which could explain the steep hillslopes and the triggering of a landslide ∼10 ka ago.

  1. Fluvial Apophenia

    Science.gov (United States)

    Coulthard, Tom; Armitage, John

    2017-04-01

    Apophenia describes the experience of seeing meaningful patterns or connections in random or meaningless data. Francis Bacon was one of the first to identify its role as a "human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds". Examples include pareidolia (seeing shapes in random patterns), gamblers fallacy (feeling past events alter probability), confirmation bias (bias to supporting a hypothesis rather than disproving), and he clustering illusion (an inability to recognise actual random data, instead believing there are patterns). Increasingly, researchers use records of past floods stored in sedimentary archives to make inferences about past environments, and to describe how climate and flooding may have changed. However, it is a seductive conclusion, to infer that drivers of landscape change can lead to changes in fluvial behaviour. Using past studies and computer simulations of river morphodynamics we explore how meaningful the link between drivers and fluvial changes is. Simple linear numerical models would suggest a direct relation between cause and effect, despite the potential for thresholds, phase changes, time-lags and damping. However, a comparatively small increase in model complexity (e.g. the Stream Power law) introducing non-linear behaviour and Increasing the complexity further can lead to the generation of time-dependent outputs despite constant forcing. We will use this range of findings to explore how apophenia may manifest itself in studies of fluvial systems, what this can mean and how we can try to account for it. Whilst discussed in the context of fluvial systems the concepts and inferences from this presentation are highly relevant to many other studies/disciplines.

  2. The ‘Grand Canyon’ of the Da'an River, Taiwan - Influences on Ultra-Rapid Incision and Knickpoint Propagation

    Science.gov (United States)

    Cook, K. L.; Suppe, J.

    2009-12-01

    The 1999 magnitude 7.6 Chi-Chi earthquake resulted in significant surface uplift along the rupture zone in western Taiwan. At northeastern-most end of the rupture zone, near the town of Cholan, motion on the Chelungpu fault was accommodated by growth of the Tungshi Anticline, resulting in up to 10m of surface uplift in the channel of the Da’an River. Where the river crosses the anticline, the zone of uplift is approximately 1 km wide, with a gently sloping downstream (western) limb about 400 m long and an abrupt upstream (eastern) limb less than 50 m long. The bedrock consists of the Pliocene Cholan Formation, composed of alternating sandstone, siltstone, and mudstone beds. The bedrock is quite weak and is also pervasively fractured, making it extremely easy to erode. In response to the 1999 uplift, the Da’an River has cut a dramatic gorge, with more than 20 m of incision over a very short period. The rapid pace of incision allows us to directly observe how factors such as lithology, structure, and discharge influence the evolution of an actively incising gorge. We use a series of aerial photographs to map out the development of the gorge since 1999. We monitor the more recent evolution of the system with RTK GPS surveys to measure channel profiles, laser rangefinder measurements of channel width, and terrestrial LIDAR surveys to quantify changes in the gorge walls. The channel can currently be divided into four segments: 1) A broad network of braided alluvial channels upstream of the gorge with an average slope of 1.5 cm/km, 2) A steep knickzone about 600 m long with an average slope of 2.7 cm/km, about 8 meters of ‘excess’ incision, and abundant bedrock in the channel, 3) A lower gorge zone with low slopes, averaging between 0.6 and 1.1 cm/km, a significant amount of aggradation, and relatively narrow width, as flow is confined to the incised gorge, and 4) A broad network of braided alluvial channels downstream of the gorge with an average slope of 1.5 cm

  3. Protracted fluvial recovery from medieval earthquakes, Pokhara, Nepal

    Science.gov (United States)

    Stolle, Amelie; Bernhardt, Anne; Schwanghart, Wolfgang; Andermann, Christoff; Schönfeldt, Elisabeth; Seidemann, Jan; Adhikari, Basanta R.; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

    2016-04-01

    River response to strong earthquake shaking in mountainous terrain often entails the flushing of sediments delivered by widespread co-seismic landsliding. Detailed mass-balance studies following major earthquakes in China, Taiwan, and New Zealand suggest fluvial recovery times ranging from several years to decades. We report a detailed chronology of earthquake-induced valley fills in the Pokhara region of western-central Nepal, and demonstrate that rivers continue to adjust to several large medieval earthquakes to the present day, thus challenging the notion of transient fluvial response to seismic disturbance. The Pokhara valley features one of the largest and most extensively dated sedimentary records of earthquake-triggered sedimentation in the Himalayas, and independently augments paleo-seismological archives obtained mainly from fault trenches and historic documents. New radiocarbon dates from the catastrophically deposited Pokhara Formation document multiple phases of extremely high geomorphic activity between ˜700 and ˜1700 AD, preserved in thick sequences of alternating fluvial conglomerates, massive mud and silt beds, and cohesive debris-flow deposits. These dated fan-marginal slackwater sediments indicate pronounced sediment pulses in the wake of at least three large medieval earthquakes in ˜1100, 1255, and 1344 AD. We combine these dates with digital elevation models, geological maps, differential GPS data, and sediment logs to estimate the extent of these three pulses that are characterized by sedimentation rates of ˜200 mm yr-1 and peak rates as high as 1,000 mm yr-1. Some 5.5 to 9 km3 of material infilled the pre-existing topography, and is now prone to ongoing fluvial dissection along major canyons. Contemporary river incision into the Pokhara Formation is rapid (120-170 mm yr-1), triggering widespread bank erosion, channel changes, and very high sediment yields of the order of 103 to 105 t km-2 yr-1, that by far outweigh bedrock denudation rates

  4. Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision

    Science.gov (United States)

    Foster, Melissa A.; Anderson, Robert S.; Gray, Harrison J.; Mahan, Shannon A.

    2017-10-01

    The response of erosional landscapes to Quaternary climate oscillations is recorded in fluvial terraces whose quantitative interpretation requires numerical ages. We investigate gravel-capped strath terraces along the western edge of Colorado's High Plains to constrain the incision history of this shale-dominated landscape. We use 10Be and 26Al cosmogenic radionuclides (CRNs), optically stimulated luminescence (OSL), and thermally transferred OSL (TT-OSL) to date three strath terraces, all beveled in shale bedrock and then deposited upon by Lefthand Creek, which drains the crystalline core of the Front Range. Our study reveals: (i) a long history (hundreds of thousands of years) of fluvial occupation of the second highest terrace, T2 (Table Mountain), with fluvial abandonment at 92 ± 3 ka; (ii) a brief occupation of a narrow and spatially confined terrace, T3, at 98 ± 7 ka; and (iii) a 10-25 thousand year period of cutting and fluvial occupation of a lower terrace, T4, marked by the deposition of a lower alluvial unit between 59 and 68 ka, followed by deposition of an upper alluvial package at 40 ± 3 ka. In conjunction with other recent CRN studies of strath terraces along the Colorado Front Range (Riihimaki et al., 2006; Dühnforth et al., 2012), our data reveal that long periods of lateral planation and fluvial occupation of strath terraces, sometimes lasting several glacial-interglacial cycles, are punctuated by brief episodes of rapid vertical bedrock incision. These data call into question what a singular terrace age represents, as the strath may be cut at one time (its cutting-age) and the terrace surface may be abandoned at a much later time (its abandonment age), and challenge models of strath terraces that appeal to simple pacing by the glacial-interglacial cycles.

  5. Influence of system controls on the Late Quaternary geomorphic evolution of a rapidly-infilled incised-valley system: The lower Manawatu valley, North Island New Zealand

    Science.gov (United States)

    Clement, Alastair J. H.; Fuller, Ian C.

    2018-02-01

    The Manawatu incised-valley estuary was rapidly infilled between 12,000-4700 cal. yr BP. A combination of empirical measurements of sedimentation rates, a reconstruction of relative sea-level (RSL) change, and digital elevation models of key surfaces within the Holocene sedimentary fill of the valley were integrated to produce a numerical model to investigate the influence of the system controls of sea-level change, sediment flux, and accommodation space on the rapid infilling history of the palaeo-estuary. The numerical model indicates that sediment flux into the palaeo-estuary was greatest during the Holocene marine transgression between 12,000-8000 years BP. The average rate of sediment deposition in the estuary during this period was 1.0 M m3 yr- 1. This rapid rate of sedimentation was controlled by the rate of accommodation space creation, as regulated by the rate of sea-level rise and the antecedent configuration of the valley. By the time sea levels stabilised c. 7500 cal. yr BP, the palaeo-estuary had been substantively infilled. Limited accommodation space resulted in rapid infilling of the central basin, though sediment flux into the estuary between 7100 and 4500 cal. yr BP was at a lower rate of 234,000 m3 yr- 1. The limited accommodation space also influenced hydrodynamic conditions in the estuarine central basin, driving export of fine-grained sediment from the estuary. Once the accommodation space of the estuarine basin was infilled sediment bypassed the system, with a consequent reduction in the sedimentation rate in the valley. More accurate partitioning of the sources of sediment driving the infilling is necessary to quantify sediment bypassing. Post-depositional lowering of RSL index points from the valley is driven by neotectonics and sediment compaction.

  6. Rapid anthropogenic response to short-term aeolian-fluvial palaeoenvironmental changes during the Late Pleistocene-Holocene transition in the northern Negev Desert, Israel

    Science.gov (United States)

    Roskin, Joel; Katra, Itzhak; Agha, Nuha; Goring-Morris, A. Nigel; Porat, Naomi; Barzilai, Omry

    2014-09-01

    Archaeological investigations along Nahal Sekher on the eastern edge of Israel's northwestern Negev Desert dunefield revealed concentrations of Epipalaeolithic campsites associated respectively with ancient water bodies. This study, aimed at better understanding the connections between these camps and the water bodies, is concerned with a cluster of Natufian sites. A comprehensive geomorphological study integrating field mapping, stratigraphic sections, sedimentological analysis and optically stimulated luminescence (OSL) ages was conducted in the vicinity of a recently excavated Natufian campsite of Nahal Sekher VI whose artifacts directly overlay aeolian sand dated by OSL to 12.4 ± 0.7 and 11.7 ± 0.5 ka. Residual sequences of diagnostic silty sediments, defined here as low-energy fluvial fine-grained deposits (LFFDs), were identified within the drainage system of central Nahal Sekher around the Nahal Sekher VI site. LFFD sections were found to represent both shoreline and mid-water deposits. The thicker mid-water LFFD deposits (15.7 ± 0.7-10.7 ± 0.5 ka) date within the range of the Epipalaeolithic campsites, while the upper and shoreline LFFD units that thin out into the sands adjacent to the Nahal Sekher VI site display slightly younger ages (10.8 ± 0.4 ka-7.6 ± 0.4 ka). LFFD sedimentation by low-energy concentrated flow and standing-water developed as a result of proximal downstream dune-damming. These water bodies developed as a result of encroaching sand that initially crossed central Nahal Sekher by 15.7 ± 0.7 ka and probably intermittently blocked the course of the wadi. LFFD deposition was therefore a response to a unique combination of regional sand supply due to frequent powerful winds and does not represent climate change in the form of increased precipitation or temperature change. The chronostratigraphies affiliate the Natufian sites to the adjacent ancient water bodies. These relations reflect a rapid, but temporary anthropogenic response to a

  7. Simulation of channel sandstone architecture in an incised valley

    Energy Technology Data Exchange (ETDEWEB)

    Frykman, P.; Johannessen, P.; Andsbjerg, J.

    1998-12-31

    The present report describes a geostatistical modelling study that is aimed at reflecting the architecture of the channel sandstones in an incised valley fill. The example used for this study is a part of the Middle Jurassic sandy succession of the Bryne Formation in the Danish central Graben. The succession consists mainly of fluvial sediments in the lower part, overlain by tidal influenced sediments, which again is overlain by shallow marine sediments. The modelling study has been performed on a sequence of incised valley sediments in the upper part of the Bryne Formation overlying fluvial sediments. (au) EFP-96. 19 refs.

  8. Fluvial archives, a valuable record of vertical crustal deformation

    Science.gov (United States)

    Demoulin, A.; Mather, A.; Whittaker, A.

    2017-06-01

    The study of drainage network response to uplift is important not only for understanding river system dynamics and associated channel properties and fluvial landforms, but also for identifying the nature of crustal deformation and its history. In recent decades, geomorphic analysis of rivers has proved powerful in elucidating the tectonic evolution of actively uplifting and eroding orogens. Here, we review the main recent developments that have improved and expanded qualitative and quantitative information about vertical tectonic motions (the effects of horizontal deformation are not addressed). Channel long profiles have received considerable attention in the literature, and we briefly introduce basic aspects of the behaviour of bedrock rivers from field and numerical modelling perspectives, before describing the various metrics that have been proposed to identify the information on crustal deformation contained within their steady-state characteristics. Then, we review the literature dealing with the transient response of rivers to tectonic perturbation, through the production of knickpoints propagating through the drainage network. Inverse modelling of river profiles for uplift in time and space is also shown to be very effective in reconstructing regional tectonic histories. Finally, we present a synthetic morphometric approach for deducing the tectonic record of fluvial landscapes. As well as the erosional imprint of tectonic forcing, sedimentary deposits, such as fluvial terrace staircases, are also considered as a classical component of tectonic geomorphology. We show that these studies have recently benefited from rapid advances in dating techniques, allowing more reliable reconstruction of incision histories and estimation of incision rates. The combination of progress in the understanding of transient river profiles and larger, more rigorous data sets of terrace ages has led to improved understanding of river erosion and the implications for terrace

  9. Minimal abdominal incisions

    Directory of Open Access Journals (Sweden)

    João Carlos Magi

    2017-04-01

    Full Text Available Minimally invasive procedures aim to resolve the disease with minimal trauma to the body, resulting in a rapid return to activities and in reductions of infection, complications, costs and pain. Minimally incised laparotomy, sometimes referred to as minilaparotomy, is an example of such minimally invasive procedures. The aim of this study is to demonstrate the feasibility and utility of laparotomy with minimal incision based on the literature and exemplifying with a case. The case in question describes reconstruction of the intestinal transit with the use of this incision. Male, young, HIV-positive patient in a late postoperative of ileotiflectomy, terminal ileostomy and closing of the ascending colon by an acute perforating abdomen, due to ileocolonic tuberculosis. The barium enema showed a proximal stump of the right colon near the ileostomy. The access to the cavity was made through the orifice resulting from the release of the stoma, with a lateral-lateral ileo-colonic anastomosis with a 25 mm circular stapler and manual closure of the ileal stump. These surgeries require their own tactics, such as rigor in the lysis of adhesions, tissue traction, and hemostasis, in addition to requiring surgeon dexterity – but without the need for investments in technology; moreover, the learning curve is reported as being lower than that for videolaparoscopy. Laparotomy with minimal incision should be considered as a valid and viable option in the treatment of surgical conditions. Resumo: Procedimentos minimamente invasivos visam resolver a doença com o mínimo de trauma ao organismo, resultando em retorno rápido às atividades, reduções nas infecções, complicações, custos e na dor. A laparotomia com incisão mínima, algumas vezes referida como minilaparotomia, é um exemplo desses procedimentos minimamente invasivos. O objetivo deste trabalho é demonstrar a viabilidade e utilidade das laparotomias com incisão mínima com base na literatura e

  10. Quaternary Morphodynamics of Fluvial Dispersal Systems Revealed: The Fly River, PNG, and the Sunda Shelf, SE Asia, simulated with the Massively Parallel GPU-based Model 'GULLEM'

    Science.gov (United States)

    Aalto, R. E.; Lauer, J. W.; Darby, S. E.; Best, J.; Dietrich, W. E.

    2015-12-01

    During glacial-marine transgressions vast volumes of sediment are deposited due to the infilling of lowland fluvial systems and shallow shelves, material that is removed during ensuing regressions. Modelling these processes would illuminate system morphodynamics, fluxes, and 'complexity' in response to base level change, yet such problems are computationally formidable. Environmental systems are characterized by strong interconnectivity, yet traditional supercomputers have slow inter-node communication -- whereas rapidly advancing Graphics Processing Unit (GPU) technology offers vastly higher (>100x) bandwidths. GULLEM (GpU-accelerated Lowland Landscape Evolution Model) employs massively parallel code to simulate coupled fluvial-landscape evolution for complex lowland river systems over large temporal and spatial scales. GULLEM models the accommodation space carved/infilled by representing a range of geomorphic processes, including: river & tributary incision within a multi-directional flow regime, non-linear diffusion, glacial-isostatic flexure, hydraulic geometry, tectonic deformation, sediment production, transport & deposition, and full 3D tracking of all resulting stratigraphy. Model results concur with the Holocene dynamics of the Fly River, PNG -- as documented with dated cores, sonar imaging of floodbasin stratigraphy, and the observations of topographic remnants from LGM conditions. Other supporting research was conducted along the Mekong River, the largest fluvial system of the Sunda Shelf. These and other field data provide tantalizing empirical glimpses into the lowland landscapes of large rivers during glacial-interglacial transitions, observations that can be explored with this powerful numerical model. GULLEM affords estimates for the timing and flux budgets within the Fly and Sunda Systems, illustrating complex internal system responses to the external forcing of sea level and climate. Furthermore, GULLEM can be applied to most ANY fluvial system to

  11. Canyon incision chronology based on ignimbrite stratigraphy and cut-and-fill sediment sequences in SW Peru documents intermittent uplift of the western Central Andes

    Science.gov (United States)

    Thouret, Jean-Claude; Gunnell, Yanni; Jicha, Brian R.; Paquette, Jean-Louis; Braucher, Régis

    2017-12-01

    Based on an 40Ar/39Ar- and U/Pb-based chronostratigraphy of ignimbrite sheets and the geomorphological features of watersheds, river profiles and slope deposits in the Ocoña-Cotahuasi-Marán (OCM) and Colca valleys of southwest Peru, we reconstruct the valley incision history of the western Central Andes over the last c. 25 Myr. We further document the Pleistocene and Holocene evolution of deep valleys on the basis of 14 10Be surface-exposure ages obtained on debris-avalanche deposits and river straths. The data suggest that uplift was gradual over the past 25 Myr, but accelerated after c. 9 Ma. Valley incision started around 11-9 Ma and accelerated between 5 and 4 Ma. Incision was followed by several pulses of valley cut-and-fill after 2.3 Ma. Evidence presented suggest that the post-5 Ma sequence of accelerated canyon incision probably resulted from a combination of drainage piracy from the Cordilleran drainage divide towards the Altiplano, accentuated flexural tilting of the Western Cordillera towards the SE, and increased rainfall on the Altiplano after late Miocene uplift of the Eastern Cordillera. The valley deepening and slope steepening driven by tectonic uplift gave rise to large occurrences of rockslope failure. The collapsed rock masses periodically obstructed the canyons, thus causing abrupt changes in local base levels and interfering with the steadiness of fluvial incision. As a result, channel aggradation has prevailed in the lower-gradient, U-shaped Pacific-rim canyons, whereas re-incision through landslide deposits has occurred more rapidly across the steeper V-shaped, upper valleys. Existing canyon knickpoints are currently arrested at the boundary between the plutonic bedrock and widespread outcrops of middle Miocene ignimbritic caprock, where groundwater sapping favouring rock collapse may be the dominant process driving headward erosion.

  12. Beaver damming, fluvial geomorphology, and climate in Yellowstone National Park, Wyoming

    Science.gov (United States)

    Persico, L.; Meyer, G.

    2008-12-01

    Beaver habitation is an important component of many fluvial landscapes that can impact a variety of hydrologic, geomorphic, and ecologic processes. Beaver damming, via long term valley aggradation, is thought to be important to the postglacial geomorphic evolution of many smaller mountain stream networks in the western United States. Loss of beaver dams can also cause rapid channel incision. Although several studies have documented rapid short-term aggradation of channels behind single beaver dams, there is little actual data on the long-term cumulative effect of beaver damming. In Yellowstone''s Northern Range, field surveys and stratigraphic section along six streams in the Northern Range reveal net thickness of mostly beaver-pond deposits. We estimate that reaches with clear morphologic and stratigraphic evidence for beaver-related aggradation constitute about 19% of the total stream network length. Reaches with probable and possible beaver-related aggradation make up an additional 8% and 2% of the network, respectively. The remaining 71% of the network has no clear evidence for beaver-related aggradation. Thirty-nine radiocarbon ages on beaver-pond deposits in northern Yellowstone fall primarily within the last 4000 yr, but gaps in dated beaver occupation from 2200-1800 and 950-750 cal yr BP correspond with severe and persistent droughts that likely caused low to ephemeral discharges in smaller streams. In the last two decades, severe drought has also caused streams that were occupied by beaver in the 1920s to become ephemeral. Beaver have been largely absent from the Northern Range since the mid-20th century, probably due to multiple ecological and climatic factors. This loss of beaver is thought to have led to widespread degradation of stream and riparian habitat via channel incision. Although 20th-century beaver loss has caused significant channel incision at some former dam sites, downcutting elsewhere in northern Yellowstone is unrelated to beaver dams or

  13. The inverted Batman incision: a new incision in transcolumellar incision for open rhinoplasty.

    Science.gov (United States)

    Nakanishi, Yuji; Nagasao, Tomohisa; Shimizu, Yusuke; Miyamoto, Junpei; Fukuta, Keizo; Kishi, Kazuo

    2013-12-01

    Columellar and nostril shapes often present irregularity after transcolumellar incision for open rhinoplasty, because of the contracture of the incised wound. The present study introduces a new technique to prevent this complication, and verifies its efficacy in improving cosmetic appearance. In our new method, a zig-zag incision with three small triangular flaps is made on the columella and in the pericolumellar regions of the bilateral nostril rims. Since the shape of the incision resembles the contour of an inverted "batman", we term our new method the "Inverted Batman" incision. To verify the effectiveness of the Inverted Batman incision, aesthetic evaluation was conducted for 21 patients operated on using the conventional transcolumellar incision (Conventional Group) and 19 patients operated on using the Inverted Batman incision (Inverted Batman Group). The evaluation was performed by three plastic surgeons, using a four-grade scale to assess three separate items: symmetry of bilateral soft triangles, symmetry of bilateral margins of the columella, and evenness of the columellar surface. The scores of the two groups for these three items were compared using a non-parametric test (Mann-Whitney U-test). With all three items, the Inverted Batman group patients present higher scores than Conventional Group patients. The Inverted Batman incision is effective in preserving the correct anatomical structure of the columella, soft triangle, and nostril rims. Hence, we recommend the Inverted Batman incision as a useful technique for open rhinoplasty.

  14. The Gediz River fluvial archive

    NARCIS (Netherlands)

    Maddy, D.; Veldkamp, A.; Demir, T.; Gorp, van W.; Wijbrans, J.R.; Hinsbergen, van D.J.J.; Dekkers, M.J.; Schreve, D.; Schoorl, J.M.; Scaife, R.

    2017-01-01

    The Gediz River, one of the principal rivers of Western Anatolia, has an extensive Pleistocene fluvial archive that potentially offers a unique window into fluvial system behaviour on the western margins of Asia during the Quaternary. In this paper we review our work on the Quaternary Gediz River

  15. Craniosynostosis incision: scalpel or cautery?

    Science.gov (United States)

    Wood, Jeyhan S; Kittinger, Benjamin J; Perry, Victor L; Adenola, Adeyemi; van Aalst, John A

    2014-07-01

    There is an ongoing debate regarding the optimal instrument for scalp incisions: the scalpel or electrocautery. The argument generally focuses on improved healing after an incision made with a knife and decreased bleeding when using electrocautery. This study compares the use of scalpel and electrocautery in making coronal incisions for patients undergoing surgical correction of craniosynostosis. The outcome metric used is wound healing within 6 months after surgery. All patients presenting to the University of North Carolina Children's Hospital with craniosynostosis between July 1, 2007 and January 1, 2010 requiring a coronal incision for surgical correction were prospectively enrolled. In all of these patients, half of the coronal incision was made with knife; the other half, with needle tip cautery. Side of the incision was specified at the time of surgery in the operative report. Patients were excluded from the study if the instrument for incision was not specified or if only 1 modality was used for the entire incision. Sixty-eight patients underwent cranial vault reconstruction, of which 58 met inclusion criteria. Of the 58 matched pairs, 55 were analyzed statistically. The 3 excluded cases were those who had midline complications. There were 17 wound complications (15%): 8 in the knife group, 6 in the cautery group, and 3 at midline (with indeterminate side for the problem). We found no statistically significant difference in wound healing between incisions made with a knife or with electrocautery.

  16. Stratigraphic architecture of back-filled incised-valley systems: Pennsylvanian-Permian lower Cutler beds, Utah, USA

    Science.gov (United States)

    Wakefield, Oliver J. W.; Mountney, Nigel P.

    2013-12-01

    The Pennsylvanian to Permian lower Cutler beds collectively form the lowermost stratigraphic unit of the Cutler Group in the Paradox Basin, southeast Utah. The lower Cutler beds represent a tripartite succession comprising lithofacies assemblages of aeolian, fluvial and shallow-marine origin, in near equal proportion. The succession results from a series of transgressive-regressive cycles, driven by repeated episodes of climatic variation and linked changes in relative sea-level. Relative sea-level changes created a number of incised-valleys, each forming through fluvial incision during lowered base-level. Aeolian dominance during periods of relative sea-level lowstand aids incised-valley identification as the erosive bounding surface juxtaposes incised-valley infill against stacked aeolian faces. Relative sea-level rises resulted in back-flooding of the incised-valleys and their infill via shallow-marine and estuarine processes. Back-flooded valleys generated marine embayments within which additional local accommodation was exploited. Back-filling is characterised by a distinctive suite of lithofacies arranged into a lowermost, basal fill of fluvial channel and floodplain architectural elements, passing upwards into barform elements with indicators of tidal influence, including inclined heterolithic strata and reactivation surfaces. The incised-valley fills are capped by laterally extensive and continuous marine limestone elements that record the drowning of the valleys and, ultimately, flooding and accumulation across surrounding interfluves (transgressive surface). Limestone elements are characterised by an open-marine fauna and represent the preserved expression of maximum transgression.

  17. The fourth incision: a cosmetic autopsy incision technique.

    Science.gov (United States)

    Patowary, Amarjyoti

    2010-03-01

    Autopsy procedure includes thorough external examination as well as internal examination including opening of all the body cavities for proper visualization of all the visceral organs. As such, there remains incision marks with stitches which harts the sentiment of the already traumatized relatives of the deceased. Moreover, it looks odd especially in cases of otherwise healthy dead bodies. So, autopsy incisions should be such that, we can get maximum possible visualization of the body cavities, particularly the thorax and abdomen, and at the same time the incision as well as the stitch marks are also hidden. This article is aimed to describe few modifications in the autopsy incisions for opening the thorax and abdomen and also proper visualization of the neck structures during autopsy where the incisions and the stitches are kept hidden.

  18. Seismic evidence of glacial-age river incision into the Tahaa barrier reef, French Polynesia

    Science.gov (United States)

    Toomey, Michael; Woodruff, Jonathan D.; Ashton, Andrew D.; Perron, J. Taylor

    2016-01-01

    Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.

  19. Fluvial Connectivity and Sediment Dispersal within Continental Extensional Basins; Assessment of Controlling Factors using Numerical Modelling

    Science.gov (United States)

    Geurts, A., Jr.; Cowie, P. A.; Gawthorpe, R.; Huismans, R. S.; Pedersen, V. K.

    2017-12-01

    Progressive integration of drainage networks has been documented in many regional-scale studies of extensional continental systems. While endorheic drainage and lake sedimentation are common features observed in basin stratigraphy, they often disappear from the record due to the development of a through-going river network. Because changes in the fluvial connectivity of extensional basins have profound impact on erosion and sediment dispersal, and thus the feedback between surface processes and tectonics, it is of great importance to understand what controls them. Headward erosion (also called headward capture or river piracy) is often suggested to be the main mechanism causing basins to become interconnected over time with one another and with the regional/coastal drainage network. We show that overspill mechanisms (basin over-filling or lake over-spilling) play a key role in the actively extending central Italian Apennines, even though this area is theoretically favorable for headward erosion (short distances to the coast in combination with rapid surface uplift). In other tectonic settings (e.g. contractional basins and high plateaux) the role of headward erosion in transverse drainage development and integrating endorheic basins has also been increasingly questioned. These two mechanisms predict very different spatio-temporal patterns of sediment dispersal and thus timing of sediment loading (or erosional unloading) along active normal faults, which in turn may influence the locus of subsequent extensional deformation. By means of surface process modelling we develop a process-based understanding of the controls on fluvial connectivity between extensional basins in the central Italian Apennines. We focus on which conditions (tectonic and erosional) favour headward erosion versus overspill and compare our model results with published field evidence for drainage integration and the timing of basin sedimentation/incision.

  20. Liquid in the major incision

    International Nuclear Information System (INIS)

    Herrera Jaramillo, Diego Alberto; Ortega Jaramillo, Hector

    2003-01-01

    We present the case of a patient with spill pleural extending in the left major incision. In the chest thorax PA, we could observe one of the complex radiographic appearances that take the reconfiguration of fluid in this localization, being this appearance dependent of the patient's position. Some points are also discussed on the anatomy of the major incisions and some of their radiographic characteristics

  1. Deciphering Fluvial-Capture-Induced Erosional Patterns at the Continental Scale on the Iberian Peninsula

    Science.gov (United States)

    Anton, L.; Munoz Martin, A.; De Vicente, G.; Finnegan, N. J.

    2017-12-01

    The process of river incision into bedrock dictates the landscape response to changes in climate and bedrock uplift in most unglaciated settings. Hence, understanding processes of river incision into bedrock and their topographic signatures are a basic goal of geomorphology. Formerly closed drainage basins provide an exceptional setting for the quantification of long term fluvial dissection and landscape change, making them valuable natural laboratories. Internally drained basins are peculiar because they trap all the sediment eroded within the watershed; as closed systems they do not respond to the base level of the global ocean and deposition is the dominant process. In that context, the opening of an outward drainage involves a sudden lowering of the base level, which is transmitted upstream along fluvial channels in the form of erosional waves, leading to high incision and denudation rates within the intrabasinal areas. Through digital topographic analysis and paleolandscape reconstruction based on relict deposits and landscapes on the Iberian Peninsula, we quantify the volume of sediments eroded from formerly internally drained basins since capture. Mapping of fluvial dissection patterns reveals how, and how far, regional waves of incision have propagated upstream. In our analysis, erosional patterns are consistent with the progressive establishment of an outward drainage system, providing a relative capture chronology for the different studied basins. Divide migration inferred from chi maps supports the interpretations based on fluvial dissection patterns and volumes, providing clues on how landscaped changed and how drainage integration occurred within the studied watersheds. [Funded by S2013/MAE-2739 and CGL2014-59516].

  2. Single incision pediatric endoscopic surgery: advantages of relatively large incision

    International Nuclear Information System (INIS)

    Yilmaz, E.; Afsarlar, E.; Karaman, I.

    2015-01-01

    To describe Single Incision Pediatric Endoscopic Surgery (SIPES) performed on children with various diagnoses, emphasizing its advantages. Study Design: An observational case series. Place and Duration of Study: Department of Pediatric Surgery, Dr. Sami Ulus Maternity and Child Health Hospital, Ankara, Turkey, from January 2011 to November 2014. Methodology: A review of patient charts was conducted in which SIPES was preferred as the surgical procedure. Patient demographics, operative details, operative time, clinical outcomes, postoperative pain and cosmesis were analyzed. Results: SIPES was performed on 45 patients (21 girls, 24 boys). Thirty-three appendectomies, 5 varicocelectomies, 3 oophorectomies, 2 ovarian and one paratubal cyst excision, and one fallopian tube excision were performed. All except one procedures were performed through our standard 2cm umbilical vertical or smile incision. In 18 cases, abdominal irrigation/aspiration was easily performed through the existing larger incision, as is done with open surgical technique. None of the patients had early postoperative shoulder/back pain since complete disinflation of CO/sub 2/ could be ensured. All of the patients/parents were satisfied with the cosmesis. Conclusion: SIPES has the advantages of limiting the surgical scar to within the umbilicus and providing easy disinflation of CO/sub 2/, allowing intraabdominal cleaning and extraction of large volume tissue samples through a single large umbilical incision. (author)

  3. Fluvial systems and their sedimentary models

    Directory of Open Access Journals (Sweden)

    Dragomir Skabeme

    1995-12-01

    Full Text Available The Slovenian géomorphologie and sedimentologie terminology for fluvial depositional environments is not established yet. Therefore a classification and the proposal for Slovenian names of fluvial sedimentary and erosional forms and influences controlling them are discussed. Attention is given to the problems of recognition of sedimentary environments in sedimentary rocks, and to fluvial sedimentary models.

  4. Superficial parotidectomy via facelift incision

    NARCIS (Netherlands)

    Lohuis, Peter J. F. M.; Tan, M. Liane; Bonte, Katrien; van den Brekel, Michiel W. M.; Balm, Alfons J. M.; Vermeersch, Hubert B.

    2009-01-01

    The stigma of a visually prominent facial scar following parotid surgery can be distressing to a young patient. The surgical technique of parotidectomy via a facelift incision is described and evaluated. Thirty patients with a benign lesion of the parotid gland underwent a partial superficial

  5. Fluvial Responses to Holocene sea Level Variations Along the Macdonald River, New South Wales, Australia

    Science.gov (United States)

    Rustomji, P.; Chappell, J.; Olley, J.

    2003-12-01

    some 35km of river, mostly upstream of the tidal limit, and meanders were cut off. The bed aggraded by 3m and the point of intersection of the river bed with MSL shifted 7.6km down valley. The channel has contracted since these floods and is building a new floodplain below the post-1500 BP inset floodplain. The late Holocene fluvial history of the Macdonald River is one of rapid adjustment to falling base level. The formation of the major fluvial landforms of the valley coinciding with late Holocene sea level at +1 to +2m, followed by subsequent abandonment of this surface with associated bed incision and channel straightening, may be a common phenomenon along river systems of eastern Australia. If so it may explain the propensity for instability of rivers along the New South Wales coast.

  6. Postoperative Granulomas at Liposuction Incision Sites.

    Science.gov (United States)

    Weniger, Frederick G; White, Peter F; Barrero Castedo, Carlos E

    2016-02-01

    Since most liposuction incisions heal uneventfully, difficult healing in such incisions must be investigated. In the cases of two gynecomastia liposuction patients in which a water-based lubricating gel was used on the liposuction incisions, the incisions failed to heal. For both patients, workup uncovered palisading granulomas at the lateral inframammary fold incision sites several months after otherwise successful surgeries. These two cases are presented and the previous literature is reviewed, with consideration given to the etiology and prevention of such granulomas. LEVEL OF EVIDENCE 5: Risk. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  7. Analytically based forward and inverse models of fluvial landscape evolution during temporally continuous climatic and tectonic variations

    Science.gov (United States)

    Goren, Liran; Petit, Carole

    2017-04-01

    Fluvial channels respond to changing tectonic and climatic conditions by adjusting their patterns of erosion and relief. It is therefore expected that by examining these patterns, we can infer the tectonic and climatic conditions that shaped the channels. However, the potential interference between climatic and tectonic signals complicates this inference. Within the framework of the stream power model that describes incision rate of mountainous bedrock rivers, climate variability has two effects: it influences the erosive power of the river, causing local slope change, and it changes the fluvial response time that controls the rate at which tectonically and climatically induced slope breaks are communicated upstream. Because of this dual role, the fluvial response time during continuous climate change has so far been elusive, which hinders our understanding of environmental signal propagation and preservation in the fluvial topography. An analytic solution of the stream power model during general tectonic and climatic histories gives rise to a new definition of the fluvial response time. The analytic solution offers accurate predictions for landscape evolution that are hard to achieve with classical numerical schemes and thus can be used to validate and evaluate the accuracy of numerical landscape evolution models. The analytic solution together with the new definition of the fluvial response time allow inferring either the tectonic history or the climatic history from river long profiles by using simple linear inversion schemes. Analytic study of landscape evolution during periodic climate change reveals that high frequency (10-100 kyr) climatic oscillations with respect to the response time, such as Milankovitch cycles, are not expected to leave significant fingerprints in the upstream reaches of fluvial channels. Linear inversion schemes are applied to the Tinee river tributaries in the southern French Alps, where tributary long profiles are used to recover the

  8. Which DEM is best for analyzing fluvial landscape development in mountainous terrains?

    Science.gov (United States)

    Boulton, Sarah J.; Stokes, Martin

    2018-06-01

    Regional studies of fluvial landforms and long-term (Quaternary) landscape development in remote mountain landscapes routinely use satellite-derived DEM data sets. The SRTM and ASTER DEMs are the most commonly utilised because of their longer availability, free cost, and ease of access. However, rapid technological developments mean that newer and higher resolution DEM data sets such as ALOS World 3D (AW3D) and TanDEM-X are being released to the scientific community. Geomorphologists are thus faced with an increasingly problematic challenge of selecting an appropriate DEM for their landscape analyses. Here, we test the application of four medium resolution DEM products (30 m = SRTM, ASTER, AW3D; 12 m = TanDEM-X) for qualitative and quantitative analysis of a fluvial mountain landscape using the Dades River catchment (High Atlas Mountains, Morocco). This landscape comprises significant DEM remote sensing challenges, notably a high mountain relief, steep slopes, and a deeply incised high sinuosity drainage network with narrow canyon/gorge reaches. Our goal was to see which DEM produced the most representative best fit drainage network and meaningful quantification. To achieve this, we used ArcGIS and Stream Profiler platforms to generate catchment hillshade and slope rasters and to extract drainage network, channel long profile and channel slope, and area data. TanDEM-X produces the clearest landscape representation but with channel routing errors in localised high relief areas. Thirty-metre DEMs are smoother and less detailed, but the AW3D shows the closest fit to the real drainage network configuration. The TanDEM-X elevation values are the closest to field-derived GPS measurements. Long profiles exhibit similar shapes but with minor differences in length, elevation, and the degree of noise/smoothing, with AW3D producing the best representation. Slope-area plots display similarly positioned slope-break knickpoints with modest differences in steepness and concavity

  9. Ridge Orientations of the Ridge-Forming Unit, Sinus Meridiani, Mars-A Fluvial Explanation

    Science.gov (United States)

    Wilkinson, M. Justin; Herridge, A.

    2013-01-01

    Imagery and MOLA data were used in an analysis of the ridge-forming rock unit (RFU) exposed in Sinus Meridiani (SM). This unit shows parallels at different scales with fluvial sedimentary bodies. We propose the terrestrial megafan as the prime analog for the RFU, and likely for other members of the layered units. Megafans are partial cones of fluvial sediment, with radii up to hundreds of km. Although recent reviews of hypotheses for the RFU units exclude fluvial hypotheses [1], inverted ridges in the deserts of Oman have been suggested as putative analogs for some ridges [2], apparently without appreciating The wider context in which these ridges have formed is a series of megafans [3], a relatively unappreciated geomorphic feature. It has been argued that these units conform to the megafan model at the regional, subregional and local scales [4]. At the regional scale suites of terrestrial megafans are known to cover large areas at the foot of uplands on all continents - a close parallel with the setting of the Meridiani sediments at the foot of the southern uplands of Mars, with its incised fluvial systems leading down the regional NW slope [2, 3] towards the sedimentary units. At the subregional scale the layering and internal discontinuities of the Meridiani rocks are consistent, inter alia, with stacked fluvial units [4]. Although poorly recognized as such, the prime geomorphic environment in which stream channel networks cover large areas, without intervening hillslopes, is the megafan [see e.g. 4]. Single megafans can reach 200,000 km2 [5]. Megafans thus supply an analog for areas where channel-like ridges (as a palimpsest of a prior landscape) cover the intercrater plains of Meridiani [6]. At the local, or river-reach scale, the numerous sinuous features of the RFU are suggestive of fluvial channels. Cross-cutting relationships, a common feature of channels on terrestrial megafans, are ubiquitous. Desert megafans show cemented paleo-channels as inverted

  10. Strong feedbacks between hillslope sediment production and channel incision by saltation-abrasion

    Science.gov (United States)

    Lundbek Egholm, David; Faurschou Knudsen, Mads; Sandiford, Mike

    2013-04-01

    While it is well understood that rivers erode mountain ranges by incising the bedrock and by transporting sediments away from the ranges, the basic physical mechanisms that drive long-term bedrock erosion and control the lifespan of mountain ranges remain uncertain. A particularly challenging paradox is reconciling the dichotomy associated with the high incision rates observed in active mountain belts, and the long-term (108 years) preservation of significant topographic reliefs in inactive orogenic belts (e.g. von Blankenburg, 2005). We have performed three-dimensional computational experiments with a landscape evolution model that couples bedrock landslides and sediment flux-dependent river erosion by saltation-abrasion (Sklar & Dietrich, 2004). The coupled model experiments show strong feedbacks between the channel erosion and the hillslope delivery of sediments. The feedbacks point to hillslope sediment production rate as the main control on channel erosion rates where saltation-abrasion dominates over other fluvial erosion processes. Our models results thus highlight the importance of hillslope sediment production controlled by climate and tectonic activity for scaling erosion rates in fluvial systems. Because of variations in landslide frequency, the feedbacks make tectonic activity a primary driver of fluvial erosion and help clarifying the long-standing paradox associated with the persistence of significant relief in old orogenic belts, up to several hundred-million-years after tectonic activity has effectively ceased. References F. von Blankenburg. The control mechanisms of erosion and weathering at basin scale from cosmogenic nuclides in river sediment. Earth Planet. Sci. Lett. 237, 462-479 (2005). L. S. Sklar, W. E. Dietrich. A mechanistic model for river incision into bedrock by saltating bed load. Water Resour. Res. 40, W06301 (2004).

  11. Tipping points in Anthropocene fluvial dynamics

    Science.gov (United States)

    Notebaert, Bastiaan; Broothaerts, Nils; Verstraeten, Gert; Berger, Jean-François; Houbrechts, Geoffrey

    2016-04-01

    Many rivers have undergone dramatic changes over the last millennia due to anthropogenic on- and offsite impacts. These changes have important implications for the geomorphic and hydrological functioning of the river. In this study we compare the influence of large-scaled off-site anthropogenic impact on three European river systems. We do this using traditional geomorphological methods, combined with palynological and archaeological data; for each catchment a Holocene sediment budget was constructed. The Dijle catchment is located in the central Belgian loess belt, and has undergone intense agriculture for at least the last 2000 year. Pre-Anthropocene floodplain are big marshes lacking a well-established river channel. Anthropogenic deforestation in the headwaters resulted in a sediment pulse from the Bronze Age on. In the main floodplain sediments gradually covered the peat layer, starting near a newly formed river channel and expanding over time towards the floodplain edges. In contrast, this transition is abrupt in the smaller tributary floodplains. Comparison with palynological data shows that this abrupt transition occurs when human impact reaches a certain threshold. The Valdaine region is located in the French Pre-Alps. Floodplain deposition increased over time since the Neolithic time period due to human induced and fire related soil erosion. This general aggradation trend is however interrupted by three major river incision phases which are caused by human land abandonment and dry periods. A second major change in floodplain geomorphology occurs during the High Roman Period and the last 800 year: the fine-grained meandering river changes to a gravel loaded braided river. During this period the upstream mountain reaches became a major sediment source due to deforestation, possibly combined with climate change. During the last century reforestation and land abandonment has led to a new incision phases, and floodplain are now a major source of gravel while

  12. Modified tubularized incised plate urethroplasty

    Directory of Open Access Journals (Sweden)

    Shivaji Mane

    2013-01-01

    Full Text Available Aim: To share our experience of doing tubularized incised plate urethroplasty with modifications. Materials and Methods: This is a single surgeon personal series from 2004 to 2009. One hundred patients of distal hypospadias were subjected for Snodgrass urethroplasty with preputioplasty. The age range was 1 to 5 year with mean age of 2.7 years. Selection criteria were good urethral plate, without chordee and torsion needing complete degloving. Main technical modification from original Snodgrass procedure was spongioplasty, preputioplasty, and dorsal slit when inability to retract prepuce during surgery. Results: Average follow-up period is 23 months. Seven (7% patients developed fistula and one patient had complete preputial dehiscence. Phimosis developed in three (3% patients and required circumcision. Dorsal slit was required in seven patients. One patient developed meatal stenosis in postoperative period. All other patients are passing single urinary stream and have cosmesis that is acceptable. Conclusions: Modified tubularized incised plate urethroplasty with preputioplasty effectively gives cosmetically normal looking penis with low complications.

  13. Morphology of fluvial levee series along a river under human influence, Maros River, Hungary

    Science.gov (United States)

    Kiss, Tímea; Balogh, Márton; Fiala, Károly; Sipos, György

    2018-02-01

    The development and morphometry of fluvial levees reflect the connection between channel and overbank processes, which can be altered by various human activities. The aims of this study are to investigate the morphology and spatial characteristics of fluvial levees and evaluate the role of some local- and catchment-scale human activities on their medium-term (150 years) development. This study applies LiDAR data along a 53-km-long reach of the Maros River in Hungary. Six fluvial levee types are identified based on the beginning and end of their evolution. These levee types were generated by local nineteenth century channel regulation works (cutoffs) and mid-twentieth century channel narrowing, which was caused by gravel mining and water impoundment in the upstream sections. However, other human activities also influenced the development of active fluvial levees because their horizontal evolution could have been limited by embanked flood-protection levees or the widening of low-lying floodplain benches that were generated by channel narrowing. Additionally, revetment constructions influenced their vertical parameters as higher fluvial levees developed along the fixed banks. Generally, the older active fluvial levees are wider, while the younger active levees are narrower with steeper slopes but not always lower. On the low-lying floodplain levels (benches), the youngest fluvial levees evolved quite rapidly and consist of coarser material. Currently, only 9.8- to 38-year return-period floods could cover the fluvial levees, contributing to their evolution. This fact and the development of fluvial levee series with two-three members reflect a gradual decoupling of the channel from the floodplain.

  14. Modified incision for maxillectomy: our experience.

    Science.gov (United States)

    Bhavana, Kranti; Tyagi, Isha; Ramani, Mukesh Kumar

    2012-06-01

    Radical maxillectomy has usually been done by the classical Weber Ferguson incision since age old times and still is being used widely due to its advantage of excellent exposure and minimal scarring as the incision follows the natural skin crease. In our modification of radical maxillectomy incision we avoid a scar on the midface by performing a midface degloving and combining it with a subconjunctival eye incision thus avoiding any cosmetic deformity and associated eye complication. It also avoids the late complication of cutaneous fistula following radiotherapy to these areas and due to early healing of the wound, early radiotherapy can be started.

  15. Controls on valley spacing in landscapes subject to rapid base-level fall

    Science.gov (United States)

    McGuire, Luke; Pelletier, John D.

    2015-01-01

    What controls the architecture of drainage networks is a fundamental question in geomorphology. Recent work has elucidated the mechanisms of drainage network development in steadily uplifting landscapes, but the controls on drainage-network morphology in transient landscapes are relatively unknown. In this paper we exploit natural experiments in drainage network development in incised Plio-Quaternary alluvial fan surfaces in order to understand and quantify drainage network development in highly transient landscapes, i.e. initially unincised low-relief surfaces that experience a pulse of rapid base-level drop followed by relative base-level stasis. Parallel drainage networks formed on incised alluvial-fan surfaces tend to have a drainage spacing that is approximately proportional to the magnitude of the base-level drop. Numerical experiments suggest that this observed relationship between the magnitude of base-level drop and mean drainage spacing is the result of feedbacks among the depth of valley incision, mass wasting and nonlinear increases in the rate of colluvial sediment transport with slope gradient on steep valley side slopes that lead to increasingly wide valleys in cases of larger base-level drop. We identify a threshold magnitude of base-level drop above which side slopes lengthen sufficiently to promote increases in contributing area and fluvial incision rates that lead to branching and encourage drainage networks to transition from systems of first-order valleys to systems of higher-order, branching valleys. The headward growth of these branching tributaries prevents the development of adjacent, ephemeral drainages and promotes a higher mean valley spacing relative to cases in which tributaries do not form. Model results offer additional insights into the response of initially unincised landscapes to rapid base-level drop and provide a preliminary basis for understanding how varying amounts of base-level change influence valley network morphology.

  16. Degradation of the Mitchell River fluvial megafan by alluvial gully erosion increased by post-European land use change, Queensland, Australia

    Science.gov (United States)

    Shellberg, J. G.; Spencer, J.; Brooks, A. P.; Pietsch, T. J.

    2016-08-01

    Along low gradient rivers in northern Australia, there is widespread gully erosion into unconfined alluvial deposits of active and inactive floodplains. On the Mitchell River fluvial megafan in northern Queensland, river incision and fan-head trenching into Pleistocene and Holocene megafan units with sodic soils created the potential energy for a secondary cycle of erosion. In this study, rates of alluvial gully erosion into incipiently-unstable channel banks and/or pre-existing floodplain features were quantified to assess the influence of land use change following European settlement. Alluvial gully scarp retreat rates were quantified at 18 sites across the megafan using recent GPS surveys and historic air photos, demonstrating rapid increases in gully area of 1.2 to 10 times their 1949 values. Extrapolation of gully area growth trends backward in time suggested that the current widespread phase of gullying initiated between 1880 and 1950, which is post-European settlement. This is supported by young optically stimulated luminescence (OSL) dates of gully inset-floodplain deposits, LiDAR terrain analysis, historic explorer accounts of earlier gully types, and archival records of cattle numbers and land management. It is deduced that intense cattle grazing and associated disturbance concentrated in the riparian zones during the dry season promoted gully erosion in the wet season along steep banks, adjacent floodplain hollows and precursor gullies. This is a result of reduced native grass cover, increased physical disturbance of soils, and the concentration of water runoff along cattle tracks, in addition to fire regime modifications, episodic drought, and the establishment of exotic weed and grass species. Geomorphic processes operating over geologic time across the fluvial megafan predisposed the landscape to being pushed by land used change across an intrinsically close geomorphic threshold towards instability. The evolution of these alluvial gullies is discussed

  17. Single Incision Laparoscopic Splenectomy: Our First Experiences

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    Umut Barbaros

    2011-06-01

    Full Text Available Objective: Most laparoscopic surgeons have attempted to reduce incisional morbidity and improve cosmetic outcomes by using less and smaller trocars. Single incision laparoscopic splenectomy is a new laparoscopic procedure. Herein we would like to present our experiences.Material and Methods: Between January 2009 and June 2009, data of the 7 patients who underwent single incision laparoscopic splenectomy were evaluated retrospectively.Results: There were 7 patients (5 females and 2 males with a mean age of 29.9 years. The most common splenectomy indication was idiopathic thrombocytopenic purpura. Single incision laparoscopic splenectomy was performed successfully in 6 patients. In one patient the operation was converted to an open procedure.Conclusion: With surgeons experienced in minimally invasive surgery, single incision laparoscopic splenectomy could be performed successfully. However, in order to demonstrate the differneces between standard laparoscopic splenectomy and SILS splenetomy, prospective randomized comparative studies are required.

  18. Single-incision total laparoscopic hysterectomy

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    Sinha Rakesh

    2011-01-01

    Full Text Available Single-incision laparoscopic surgery is an alternative to conventional multiport laparoscopy. Single-access laparoscopy using a transumbilical port affords maximum cosmetic benefits because the surgical incision is hidden in the umbilicus. The advantages of single-access laparoscopic surgery may include less bleeding, infection, and hernia formation and better cosmetic outcome and less pain. The disadvantages and limitations include longer surgery time, difficulty in learning the technique, and the need for specialized instruments. Ongoing refinement of the surgical technique and instrumentation is likely to expand its role in gynecologic surgery in the future. We perform single-incision total laparoscopic hysterectomy using three ports in the single transumbilical incision.

  19. 10Be and 26Al dating of river terraces and quaternary incision rates in the Ardenne massif (eastern Belgium)

    Science.gov (United States)

    Rixhon, G.; Braucher, R.; Siame, L.; Bourlès, D.; Demoulin, A.

    2009-04-01

    Because of the lack of reliable chronological data, the Quaternary evolution of the hydrographic network of the Ardennes (western continuation of the Rhenish shield, western Europe) remains still poorly known. Therefore, we measured the cosmogenic nuclides content (10Be and 26Al) of terrace sediments of Ardennian rivers (Meuse, Ourthe & Amblève) in order to date several terrace levels and to better constrain the Quaternary incision of the network. Though these dating methods are successfully used to determine ages of superficial (e.g., glacial) deposits, dating of fluvial terraces remains difficult. Possible predepositional exposures of the sampled material (inherited 10Be and 26Al) may indeed bias the measurements towards higher nuclide concentrations while several postdepositional processes (burial, erosion) may cause a lowering of the 10Be and 26Al concentrations. In an attempt to overcome these difficulties, the selected fluvial deposits (six locations) were sampled using a profiling technique on as thick as possible sections (more than 3 m). While previous studies assigned an early middle Pleistocene age (around 800 ka) to the main terrace level in the Rhine-Meuse system, our 10Be dates for the same terrace level (according to geometrical correlation) in the Amblève River, a Meuse subtributary, are much younger (upper Pleistocene). To explain this age discrepancy, we suggest that the incision was strongly diachronous from the Meuse valley towards its Ardennian headwaters, as a result of a delayed upstream propagation of the incision wave when it passes tributary junctions.

  20. Mast Quadrant-assisted Minimally Invasive Modified Transforaminal Lumbar Interbody Fusion: Single Incision Versus Double Incision

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    Xin-Lei Xia

    2015-01-01

    Full Text Available Background: The concept of minimally invasive techniques is to make every effort to reduce tissue damage. Certainly, reducing skin incision is an important part of these techniques. This study aimed to investigate the clinical feasibility of Mast Quadrant-assisted modified transforaminal lumbar interbody fusion (TLIF with a small single posterior median incision. Methods: During the period of March 2011 to March 2012, 34 patients with single-segment degenerative lumbar disease underwent the minimally invasive modified TLIF assisted by Mast Quadrant with a small single posterior median incision (single incision group. The cases in this group were compared to 37 patients with single-segment degenerative lumbar disease in the double incision group. The perioperative conditions of patients in these two groups were statistically analyzed and compared. The Oswestry Disability Index (ODI scores, Visual Analog Scale (VAS scores, and sacrospinalis muscle damage evaluation indicators before operation and 3, 12 months postoperation were compared. Results: A total of 31 and 35 cases in the single incision and double incision groups, respectively, completed at least 12 months of systemic follow-up. The differences in perioperative conditions between the two groups were not statistically significant. The incision length of the single incision group was significantly shorter than that of the double incision group (P < 0.01. The ODI and VAS scores of patients in both groups improved significantly at 3 and 12 months postoperation. However, these two indicators at 3 and 12 months postoperation and the sacrospinalis muscle damage evaluation indicators at 3 months postoperation did not differ significantly between the two groups (P ≥ 0.05. Conclusions: Mast Quadrant-assisted modified TLIF with a small single posterior median incision has excellent clinical feasibility compared to minimally invasive TLIF with a double paramedian incision.

  1. DNA Methylation Modulates Nociceptive Sensitization after Incision.

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    Yuan Sun

    Full Text Available DNA methylation is a key epigenetic mechanism controlling DNA accessibility and gene expression. Blockade of DNA methylation can significantly affect pain behaviors implicated in neuropathic and inflammatory pain. However, the role of DNA methylation with regard to postoperative pain has not yet been explored. In this study we sought to investigate the role of DNA methylation in modulating incisional pain and identify possible targets under DNA methylation and contributing to incisional pain. DNA methyltranferase (DNMT inhibitor 5-Aza-2'-deoxycytidine significantly reduced incision-induced mechanical allodynia and thermal sensitivity. Aza-2'-deoxycytidine also reduced hindpaw swelling after incision, suggesting an anti-inflammatory effect. Global DNA methylation and DNMT3b expression were increased in skin after incision, but none of DNMT1, DNMT3a or DNMT3b was altered in spinal cord or DRG. The expression of proopiomelanocortin Pomc encoding β-endorphin and Oprm1 encoding the mu-opioid receptor were upregulated peripherally after incision; moreover, Oprm1 expression was further increased under DNMT inhibitor treatment. Finally, local peripheral injection of the opioid receptor antagonist naloxone significantly exacerbated incision-induced mechanical hypersensitivity. These results suggest that DNA methylation is functionally relevant to incisional nociceptive sensitization, and that mu-opioid receptor signaling might be one methylation regulated pathway controlling sensitization after incision.

  2. Single scrotal incision orchiopexy - a systematic review

    Directory of Open Access Journals (Sweden)

    Hugo Fabiano Fernandes Novaes

    2013-06-01

    Full Text Available Objective To conduct a systematic review on single scrotal incision orchiopexy. Materials and Methods A search was performed using Pubmed, through which 16 articles were selected out of a total of 133. The following conditions were considered exclusion criteria: other surgical methods such as an inguinal procedure or a laparoscopic approach, retractile testes, or patients with previous testicular or inguinal surgery. Results A total of 1558 orchiopexy surgeries initiated with a transcrotal incision were analyzed. Patients' ages ranged between 5 months and 21 years. Thirteen studies used high scrotal incisions, and low scrotal incisions were performed in the remainder of the studies. In 55 cases (3.53%, there was a need for inguinal incision. Recurrence was observed in 9 cases, testicular atrophy in 3, testicular hypotrophy in 2, and surgical site infections in 13 cases. High efficacy rates were observed, varying between 88% and 100%. Conclusions Single scrotal incision orchiopexy proved to be an effective technique and is associated with low rates of complications.

  3. Transconjunctival incision for total maxillectomy--an alternative for subciliary incision.

    Science.gov (United States)

    Goyal, Amit; Tyagi, Isha; Jain, Shilpa; Syal, Rajan; Singh, Alok Pratap; Kapila, Rajeev

    2011-09-01

    A subciliary incision may be associated with various complications of the lower eyelid when it is used during a total maxillectomy. The use of the transconjunctival incision instead is an alternative in suitable patients. The records of 17 patients were reviewed in whom a transconjunctival incision was used during total maxillectomy. These included 13 in whom the Weber-Ferguson incision was used, and 4 who had a sublabial incision. There was mild conjunctival oedema in all the cases during the immediate postoperative period but it did not last for more than two days. Four patients had mild to moderate oedema of the lid that resolved within two days. One had mild ectropion with transient epiphora, which was caused by early removal of the medial canthal sutures. We found the approach to be cosmetically acceptable as it avoids a scar in the subciliary region. The transconjunctival incision can be used in place of the subciliary incision for lateral exposure during total maxillectomy. There are few complications associated with the lower lid, and it has good cosmetic results; if it is combined with a sublabial incision in suitable patients, the maxillectomy is virtually scar-free. Copyright © 2010 British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  4. Comparison of surgically induced astigmatism in various incisions in manual small incision cataract surgery.

    Science.gov (United States)

    Jauhari, Nidhi; Chopra, Deepak; Chaurasia, Rajan Kumar; Agarwal, Ashutosh

    2014-01-01

    To determine the surgically induced astigmatism (SIA) in Straight, Frown and Inverted V shape (Chevron) incisions in manual small incision cataract surgery (SICS). A prospective cross sectional study was done on a total of 75 patients aged 40y and above with senile cataract. The patients were randomly divided into three groups (25 each). Each group received a particular type of incision (Straight, Frown or Inverted V shape incisions). Manual SICS with intraocular lens (IOL) implantation was performed. The patients were compared 4wk post operatively for uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA) and SIA. All calculations were performed using the SIA calculator version 2.1, a free software program. The study was analyzed using SPSS version 15.0 statistical analysis software. The study found that 89.5% of patients in Straight incision group, 94.2% in Frown incision group and 95.7% in Inverted V group attained BCVA post-operatively in the range of 6/6 to 6/18. Mean SIA was minimum (-0.88±0.61D×90 degrees) with Inverted V incision which was statistically significant. Inverted V (Chevron) incision gives minimal SIA.

  5. Late Cenozoic fluvial successions in northern and western India: an overview and synthesis

    Science.gov (United States)

    Sinha, R.; Kumar, R.; Sinha, S.; Tandon, S. K.; Gibling, M. R.

    2007-11-01

    Late Cenozoic fluvial successions are widespread in India. They include the deposits of the Siwalik basin which represent the accumulations of the ancient river systems of the Himalayan foreland basin. Palaeomagnetic studies reveal that fluvial architecture and styles of deposition were controlled by Himalayan tectonics as well as by major climatic fluctuations during the long (∼13 Ma) span of formation. The Indo-Gangetic plains form the world's most extensive Quaternary alluvial plains, and display spatially variable controls on sedimentation: Himalayan tectonics in the frontal parts, climate in the middle reaches, and eustasy in the lower reaches close to the Ganga-Brahmaputra delta. Climatic effects were mediated by strong fluctuations in the SW Indian Monsoon, and Himalayan rivers occupy deep valleys in the western Ganga plains where stream power is high, cut in part during early Holocene monsoon intensification; the broad interfluves record the simultaneous aggradation of plains-fed rivers since ∼100 ka. The eastward increase in precipitation across the Ganga Plains results in rivers with low stream power and a very high sediment flux, resulting in an aggradational mode and little incision. The river deposits of semi-arid to arid western India form important archives of Quaternary climate change through their intercalation with the eolian deposits of the Thar Desert. Although the synthesis documents strong variability-both spatial and temporal-in fluvial stratigraphy, climatic events such as the decline in precipitation during the Last Glacial Maximum and monsoon intensification in the early Holocene have influenced fluvial dynamics throughout the region.

  6. Single incision laparoscopic colorectal resection: Our experience

    Directory of Open Access Journals (Sweden)

    Chinnusamy Palanivelu

    2012-01-01

    Full Text Available Background: A prospective case series of single incision multiport laparoscopic colorectal resections for malignancy using conventional laparoscopic trocars and instruments is described. Materials and Methods: Eleven patients (seven men and four women with colonic or rectal pathology underwent single incision multiport laparoscopic colectomy/rectal resection from July till December 2010. Four trocars were placed in a single transumblical incision. The bowel was mobilized laparoscopically and vessels controlled intracorporeally with either intra or extracorporeal anastomosis. Results: Three patients had carcinoma in the caecum, one in the hepatic flexure, two in the rectosigmoid, one in the descending colon, two in the rectum and two had ulcerative pancolitis (one with high grade dysplasia and another with carcinoma rectum. There was no conversion to standard multiport laparoscopy or open surgery. The median age was 52 years (range 24-78 years. The average operating time was 130 min (range 90-210 min. The average incision length was 3.2 cm (2.5-4.0 cm. There were no postoperative complications. The average length of stay was 4.5 days (range 3-8 days. Histopathology showed adequate proximal and distal resection margins with an average lymph node yield of 25 nodes (range 16-30 nodes. Conclusion: Single incision multiport laparoscopic colorectal surgery for malignancy is feasible without extra cost or specialized ports/instrumentation. It does not compromise the oncological radicality of resection. Short-term results are encouraging. Long-term results are awaited.

  7. The contribution of bank and surface sediments to fluvial sediment ...

    African Journals Online (AJOL)

    The contribution of bank and surface sediments to fluvial sediment transport of the Pra River. ... the relative contribution of surface and bank sediments to the fluvial sediment transport. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  8. Fluvial diffluence episodes reflected in the Pleistocene tufa deposits of the River Piedra (Iberian Range, NE Spain)

    Science.gov (United States)

    Vázquez-Urbez, M.; Pardo, G.; Arenas, C.; Sancho, C.

    2011-01-01

    The Pleistocene deposits of the valley of the River Piedra (NE Spain) are represented by thick tufas with small amounts of detrital material; the development of these deposits correlates with marine isotopic stages 9, 7, 6, and 5. The sedimentary scenario in which they formed mostly corresponded to stepped fluvial systems with barrage-cascade and associated dammed areas separated by low gradient fluvial stretches. Mapping and determining the sedimentology and chronology of these deposits distinguished two main episodes of fluvial diffluence that originated as a result of the temporary blockage of the river — a consequence of the vertical growth of tufa barrages in the main channel. In both episodes, water spilt out toward a secondary course from areas upstream of barrages where the water level surpassed the height of the divide between the main and secondary course. As a consequence, extensive and distinct tufa deposits with very varied facies formed over a gently inclined area toward and, indeed, within the secondary course. The hydrology of this secondary course was episodic, fed only by surface water. The two diffluence episodes detected occurred during MIS 7 and 7-6 and were interrupted by incision events, reflected by detrital deposits at the base of each tufa sedimentation stage in the main channel. Incision, which caused the breakage of the barrages, allowed water to again flow through the main channel. No evidence of diffluence was seen in any younger (MIS 5 to present-day) tufa deposits. The proposed diffluence model might help explain other carbonate fluvial systems in which (1) tufas appear in areas with no permanent water supply, and (2) tufas are absent over extensive areas despite conditions favourable to their formation.

  9. Primary closure of equine laryngotomy incisions

    DEFF Research Database (Denmark)

    Lindegaard, C.; Karlsson, L.; Ekstrøm, Claus Thorn

    2016-01-01

    incision between January 1995 and June 2012 were reviewed. Horses with a laryngotomy incision closed in three layers for primary healing were included. Descriptive data on healing characteristics and complications of laryngotomy wounds were collected from the medical records and via follow......The objective was to report healing characteristics and complications after primary closure of equine laryngotomies and analyse factors potentially associated with complications. This retrospective case series of the medical records of horses (n = 180) undergoing laryngoplasty and laryngotomy...... after primary closure of equine laryngotomy incisions are infrequent and considered of minimal severity and can be performed safely when paying careful attention to the closure of the cricothyroid membrane....

  10. A Field Exercise in Fluvial Sediment Transport.

    Science.gov (United States)

    Tharp, Thomas M.

    1983-01-01

    Describes an investigation which introduces the mathematical principles of stream hydraulics and fluvial sediment in a practical context. The investigation has four stages: defining hydrology of the stream; defining channel hydraulics in a study reach; measuring grain size; and calculating transportable grain size and comparing measure stream-bed…

  11. A fluvial mercury budget for Lake Ontario.

    Science.gov (United States)

    Denkenberger, Joseph S; Driscoll, Charles T; Mason, Edward; Branfireun, Brian; Warnock, Ashley

    2014-06-03

    Watershed mercury (Hg) flux was calculated for ten inflowing rivers and the outlet for Lake Ontario using empirical measurements from two independent field-sampling programs. Total Hg (THg) flux for nine study watersheds that directly drain into the lake ranged from 0.2 kg/yr to 13 kg/yr, with the dominant fluvial THg load from the Niagara River at 154 kg/yr. THg loss at the outlet (St. Lawrence River) was 68 kg/yr and has declined approximately 40% over the past decade. Fluvial Hg inputs largely (62%) occur in the dissolved fraction and are similar to estimates of atmospheric Hg inputs. Fluvial mass balances suggest strong in-lake retention of particulate Hg inputs (99%), compared to dissolved total Hg (45%) and methyl Hg (22%) fractions. Wetland land cover is a good predictor of methyl Hg yield for Lake Ontario watersheds. Sediment deposition studies, coupled atmospheric and fluvial Hg fluxes, and a comparison of this work with previous measurements indicate that Lake Ontario is a net sink of Hg inputs and not at steady state likely because of recent decreases in point source inputs and atmospheric Hg deposition.

  12. Utilization of alternatives fuels in a fluvial convoy; Utilizacao de combustiveis alternativos em um comboio fluvial

    Energy Technology Data Exchange (ETDEWEB)

    Padovezi, Carlos D; Giraldo, Arnaldo

    1987-12-31

    This work presents the results of tests performed with ethanol and methanol in a fluvial convoy in Tiete river, Sao Paulo State - Southeast Brazil. It also outlines a comparison and evaluation methodology. 9 figs., 3 tabs.

  13. Utilization of alternatives fuels in a fluvial convoy; Utilizacao de combustiveis alternativos em um comboio fluvial

    Energy Technology Data Exchange (ETDEWEB)

    Padovezi, Carlos D.; Giraldo, Arnaldo

    1986-12-31

    This work presents the results of tests performed with ethanol and methanol in a fluvial convoy in Tiete river, Sao Paulo State - Southeast Brazil. It also outlines a comparison and evaluation methodology. 9 figs., 3 tabs.

  14. Small Incision Cataract Surgery (SICS with Clear Corneal Incision and SICS with Scleral Incision – A Comparative Study

    Directory of Open Access Journals (Sweden)

    Md Shafiqul Alam

    2014-01-01

    Full Text Available Background: Age related cataract is the leading cause of blindness and visual impairment throughout the world. With the advent of microsurgical facilities simple cataract extraction surgery has been replaced by small incision cataract surgery (SICS with posterior chamber intra ocular lens implant, which can be done either with clear corneal incision or scleral incision. Objective: To compare the post operative visual outcome in these two procedures of cataract surgery. Materials and method: This comparative study was carried out in the department of Ophthalmology, Delta Medical College & Hospital, Dhaka, Bangladesh, during the period of January 2010 to December 2012. Total 60 subjects indicated for age related cataract surgery irrespective of sex with the age range of 40-80 years with predefined inclusion and exclusion criteria were enrolled in the study. Subjects were randomly and equally distributed in 2 groups; Group A for SICS with clear corneal incision and group B for SICS with scleral incision. Post operative visual out come was evaluated by determining visual acuity and astigmatism in different occasions and was compared between groups. Statistical analysis was done by SPSS for windows version12. Results: The highest age incidence (43.3% was found between 61 to 70 years of age group. Among study subjects 40 were male and 20 were female. Preoperative visual acuity and astigmatism were evenly distributed between groups. Regarding postoperative unaided visual outcome, 6/12 or better visual acuity was found in 19.98% cases in group A and 39.6% cases in group B at 1st week. At 6th week 6/6 vision was found in 36.3% in Group A and 56.1% in Group B and 46.2% in group A and 66% in group B without and with correction respectively. With refractive correction, 6/6 vision was attained in 60% subjects of group A and 86.67% of group B at 8th week. Post operative visual acuity was statistically significant in all occasions. Postoperative astigmatism of

  15. Transgressive systems tract development and incised-valley fills within a quaternary estuary-shelf system: Virginia inner shelf, USA

    Science.gov (United States)

    Foyle, A.M.; Oertel, G.F.

    1997-01-01

    High-frequency Quaternary glacioeustasy resulted in the incision of six moderate- to high-relief fluvial erosion surfaces beneath the Virginia inner shelf and coastal zone along the updip edges of the Atlantic continental margin. Fluvial valleys up to 5 km wide, with up to 37 m of relief and thalweg depths of up to 72 m below modern mean sea level, cut through underlying Pleistocene and Mio-Pliocene strata in response to drops in baselevel on the order of 100 m. Fluvially incised valleys were significantly modified during subsequent marine transgressions as fluvial drainage basins evolved into estuarine embayments (ancestral generations of the Chesapeake Bay). Complex incised-valley fill successions are bounded by, or contain, up to four stacked erosional surfaces (basal fluvial erosion surface, bay ravinement, tidal ravinement, and ebb-flood channel-base diastem) in vertical succession. These surfaces, combined with the transgressive oceanic ravinement that generally caps incised-valley fills, control the lateral and vertical development of intervening seismic facies (depositional systems). Transgressive stratigraphy characterizes the Quaternary section beneath the Virginia inner shelf where six depositional sequences (Sequences I-VI) are identified. Depositional sequences consist primarily of estuarine depositional systems (subjacent to the transgressive oceanic ravinement) and shoreface-shelf depositional systems; highstand systems tract coastal systems are thinly developed. The Quaternary section can be broadly subdivided into two parts. The upper part contains sequences consisting predominantly of inner shelf facies, whereas sequences in the lower part of the section consist predominantly of estuarine facies. Three styles of sequence preservation are identified. Style 1, represented by Sequences VI and V, is characterized by large estuarine systems (ancestral generations of the Chesapeake Bay) that are up to 40 m thick, have hemicylindrical wedge geometries

  16. Tectonic and lithological controls on fluvial landscape development in central-eastern Portugal: Insights from long profile tributary stream analyses

    Science.gov (United States)

    Martins, António A.; Cabral, João; Cunha, Pedro P.; Stokes, Martin; Borges, José; Caldeira, Bento; Martins, A. Cardoso

    2017-01-01

    This study examines the long profiles of tributaries of the Tagus and Zêzere rivers in Portugal (West Iberia) in order to provide new insights into patterns, timing, and controls on drainage development during the Quaternary incision stage. The studied streams are incised into a relict culminant fluvial surface, abandoned at the beginning of the incision stage. The streams flow through a landscape with bedrock variations in lithology (mainly granites and metasediments) and faulted blocks with distinct uplift rates. The long profiles of the analyzed streams record an older transitory knickpoint/knickzone separating (1) an upstream relict graded profile, with lower steepness and higher concavity, that reflects a long period of quasi-equilibrium conditions reached after the beginning of the incision stage, and (2) a downstream rejuvenated long profile, with steeper gradient and lower concavity, particularly for the final reach, which is often convex. The rejuvenated reaches testify to the upstream propagation of several incision waves, interpreted as the response of each stream to increasing crustal uplift and prolonged periods of base-level lowering by the trunk drainages, coeval with low sea level conditions. The morphological configurations of the long profiles enabled spatial and relative temporal patterns of incisions to be quantified. The incision values of streams flowing on the Portuguese Central Range (PCR; ca. 380-150 m) are variable but generally higher than the incision values of streams flowing on the adjacent South Portugal Planation Surface (SPPS; ca. 220-110 m), corroborating differential uplift of the PCR relative to the SPPS. Owing to the fact that the relict graded profiles can be correlated with the Tagus River T1 terrace (1.1-0.9 My) present in the study area, incision rates can be estimated (1) for the streams located in the PCR, 0.38-0.15 m/ky and (2) for the streams flowing on the SPPS, 0.22-0.12 m/ky. The differential uplift inferred in the

  17. The boomerang incision for periareolar breast malignancies.

    Science.gov (United States)

    Tan, Mona P

    2007-11-01

    Breast-conservation surgery has been shown to be equivalent to mastectomy in terms of long-term survival for the treatment of breast cancer. Various techniques have been described on how to achieve clear margins and good cosmetic outcomes and therefore expand the indications for breast conservation. A novel incision is detailed to augment the options already available.

  18. Single scrotal incision orchidopexy for palpable undescended

    International Nuclear Information System (INIS)

    Ahmad, A.; Safdar, C.A.; Yasir, U.; Rasool, N.; Kanwal, S.; Boota, M.; Rehman, J.U.

    2014-01-01

    To retrospectively asses the results of single scrotal incision orchidopexy (SSIO) performed at our centre with ligation of the patent processus vaginalis in children having palpable undescended testes (UDT). Study Design: Quasi-experimental with retrospective data. Place and Duration of Study: Department of Paediatric surgery Military Hospital Rawalpindi, from April 2007 to December 2011. Patients and Methods: After making a single transverse incision at superior scrotal border, the testis was identified; gubernaculums and the sac were dissected to the highest level and divided. The testis was placed into the scrotum and fixed to the scrotal fascia/skin. All patients were assessed at 2 weeks, 2 months and 6 months post operatively, and then yearly. Results: A total of 38 orchidopexies were performed in 33 patients. The patients age ranged from 14 months to 7 years (mean:2.1 years). Bilateral UDT were found in 5 patients (15.1%). Operative time ranged from 20 to 45 minutes (mean: 36 minutes). The single scrotal incision technique was successful in all 38 cases (100%). All testes were easily fixed in the scrotum. Two patients (5.2%) developed scrotal haematoma and one patient (2.6%) developed stitch abscess. All showed good an atomical and cosmetic results up to a minimum of six months of follow-up. Conclusion: Single scrotal incision orchidopexy for palpable undescended testis is a simple and safe technique. It has shown to consume shorter time and give good cosmetic results. (author)

  19. Radiological findings after endoscopic incision of ureterocele

    International Nuclear Information System (INIS)

    Cheon, Jung Eun; Kim, In One; Seok, Eul Hye; Cha, Joo Hee; Choi, Gook Myung; Kim, Woo Sun; Yeon, Kyung Mo; Kim, Kwang Myung; Choi, Hwang; Cheon, Jung Eun; Seok, Eul Hye; Cha, Joo Hee; Choi, Guk Myung

    2001-01-01

    Endoscopic incision of ureterocele is considered a simple and safe method for decompression of urinary tract obstruction above ureterocele. The purpose of this study was to evaluate the radiological findings after endoscopic incision of ureterocele. We retrospectively reviewed the radiological findings (ultrasonography (US), intravenous urography, and voiding cystourethrography(VCU)) in 16 patients with ureterocele who underwent endoscopic incision (mean age at surgery, 15 months; M:F 3:13; 18 ureteroceles). According to the postoperative results, treatment was classified as successful when medical treatment was still required, and second operation when additional surgical treatment was required. Postoperative US (n=10) showed that in all patients, urinary tract obstruction was relieved: the kidney parenchima was thicker and the ureterocele was smaller. Intravenous urography (n=8), demonstrated that in all patients, urinary tract obstruction and the excretory function of the kidney had improved. Postoperative VCU indicated that in 92% of patients (12 of 13), endoscopic incision of the ureterocele led to vesicoureteral reflux(VUR). Of these twelve, seven (58%) showed VUR of more than grade 3, while newly developed VUR was seen in five of eight patients (63%) who had preoperative VCU. Surgery was successful in four patients (25%), partially successful in three (19%), and a second operation-on account of recurrent urinary tract infection and VUR of more than grase 3 during the follow-up period-was required by nine (56%). Although endoscopic incision of a ureterocele is a useful way of relieving urinary tract obstruction, an ensuing complication may be VUR. Postoperative US and intravenous urography should be used to evaluate parenchymal change in the kidney and improvement of uronary tract obstructon, while to assess the extend of VUR during the follow-up period , postoperative VCU is required

  20. Plio-Quaternary river incision rates inferred from burial dating (Al-26/Be-10) of in cave-deposited alluvium in the Meuse catchment (E Belgium): new insights into the uplift history of the Ardennes massif

    Science.gov (United States)

    Rixhon, Gilles; Bourlès, Didier; Braucher, Régis; Peeters, Alexandre; Demoulin, Alain

    2017-04-01

    Although the Late Cenozoic uplift of the intraplate Variscan Ardennes/Rhenish massif (N Europe) has been long studied, its causes, shape and timing are still under debate (Demoulin & Hallot, 2009). This is mainly due to the scarcity of reliable ages for uplift markers, such as Quaternary terrace staircases along the deeply-incised valleys or Late Tertiary planation surfaces. In parallel, multi-level cave systems in limestone rocks, wherein abandoned phreatic passages filled with alluvium represent former phases of fluvial base-level stability, record the history of regional river incision (Anthony & Granger, 2007). Here, we present new burial ages (Al-26/Be-10) from fluvial gravels washed in a multi-level cave system developed in Devonian limestones of the lower Ourthe valley (main Ardennian tributary of the Meuse). Our results highlight a significant increase of incision rates from the Middle Pleistocene on, and allow reconstructing the incision history in the northern part of the Ardennes over the last 3.4 Ma. These long-term incision rates derived from burial ages are then discussed in relation to the existing studies dealing with river incision and/or tectonic uplift of the Ardennes/Rhenish massif (e.g. Demoulin & Hallot, 2009; Rixhon et al., 2011). Our cosmogenic nuclide ages thus enlarge the data pool required to explore the spatio-temporal characteristics of the drainage system's incision response to combined tectonic and climatic signals. References Anthony, D., Granger, D.E., 2007. A new chronology for the age of Appalachian erosional surfaces determined by cosmogenic nuclides in cave sediments. Earth Surf. Process. Landforms 32, 874-887 Demoulin, A., Hallot, E., 2009. Shape and amount of the Quaternary uplift of the western Rhenish shield and the Ardennes (western Europe). Tectonophysics 474, 696-708. Rixhon, G., et al., 2011. Quaternary river incision in NE Ardennes (Belgium): Insights from Be-10/Al-26 dating of rive terraces. Quaternary Geochronology 6

  1. Incision integrity and postoperative outcomes after microcoaxial phacoemulsification performed using 2 incision-dependent systems.

    Science.gov (United States)

    Vasavada, Vaishali; Vasavada, Abhay R; Vasavada, Viraj A; Srivastava, Samaresh; Gajjar, Devarshi U; Mehta, Siddharth

    2013-04-01

    To compare incision integrity and clinical outcomes of 2 microcoaxial phacoemulsification systems. Iladevi Cataract & IOL Research Centre, Ahmedabad, India. Prospective randomized clinical trial. Eyes were randomized to have phacoemulsification using a 1.8 mm clear corneal incision (CCI) system (Group 1, Stellaris system) or a 2.2 mm CCI system (Group 2, Intrepid Infiniti system). Incision enlargement at end of surgery was measured. At the conclusion of surgery, trypan blue was applied over the conjunctival surface, anterior chamber aspirate withdrawn, and ingress into anterior chamber measured. Postoperative observations included evaluation of the CCI using anterior segment optical coherence tomography (AS-OCT), change in central corneal thickness (CCT), and anterior segment inflammation at 1 day, 1 week, and 1 month and endothelial cell loss and surgically induced astigmatism (SIA) at 3 months. Incision enlargement (P.05). At the end of surgery, it is not the initial incision size alone but also the distortion of the incision during subsequent stages of surgery that determine the integrity of the CCI. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. COMPARISON OF POSTOP SIA IN MSICS WITH STRAIGHT INCISION VERSUS FROWN INCISION

    Directory of Open Access Journals (Sweden)

    Shayana Bhumbla

    2017-05-01

    Full Text Available BACKGROUND Surgically-Induced Astigmatism (SIA is one of the commonest causes of poor postoperative vision even after uneventful cataract surgery. Recent advances have led to a newer concept of “refractive cataract surgery.” The aim of the study is to study the comparison of postop SIA in Manual Small Incision Cataract Surgery (MSICS with straight versus frown incision. MATERIALS AND METHODS 50 patients of cataract were divided into 2 groups (25 each - group A underwent MSICS with 6 mm straight incision, group B underwent MSICS with 6 mm frown incision. BCVA, keratometry readings were recorded with auto kerato-refractometer preop, at 1 week, 1 month, 3 months and SIA was calculated with SIA calculator version 2.1, a free software program. RESULTS Mean SIA in group A and B were - 1.14D versus 0.92D at 1 week; 1.26D versus 0.97D at 1 month; 1.29D versus 0.95D at 3 months. The difference was statistically significant at each follow up visit (p<0.05. CONCLUSION Frown incision gives lesser SIA than straight incision in MSICS.

  3. Martian Fluvial Conglomerates at Gale Crater

    Science.gov (United States)

    Williams, R. M. E.; Grotzinger, J. P.; Dietrich, W. E.; Gupta, S.; Sumner, D. Y.; Wiens, R. C.; Mangold, N.; Malin, M. C.; Edgett, K. S.; Maurice, S.; Forni, O.; Gasnault, O.; Ollila, A.; Newsom, H. E.; Dromart, G.; Palucis, M. C.; Yingst, R. A.; Anderson, R. B.; Herkenhoff, K. E.; Le Mouélic, S.; Goetz, W.; Madsen, M. B.; Koefoed, A.; Jensen, J. K.; Bridges, J. C.; Schwenzer, S. P.; Lewis, K. W.; Stack, K. M.; Rubin, D.; Kah, L. C.; Bell, J. F.; Farmer, J. D.; Sullivan, R.; Van Beek, T.; Blaney, D. L.; Pariser, O.; Deen, R. G.; Kemppinen, Osku; Bridges, Nathan; Johnson, Jeffrey R.; Minitti, Michelle; Cremers, David; Edgar, Lauren; Godber, Austin; Wadhwa, Meenakshi; Wellington, Danika; McEwan, Ian; Newman, Claire; Richardson, Mark; Charpentier, Antoine; Peret, Laurent; King, Penelope; Blank, Jennifer; Weigle, Gerald; Schmidt, Mariek; Li, Shuai; Milliken, Ralph; Robertson, Kevin; Sun, Vivian; Baker, Michael; Edwards, Christopher; Ehlmann, Bethany; Farley, Kenneth; Griffes, Jennifer; Miller, Hayden; Newcombe, Megan; Pilorget, Cedric; Rice, Melissa; Siebach, Kirsten; Stolper, Edward; Brunet, Claude; Hipkin, Victoria; Léveillé, Richard; Marchand, Geneviève; Sobrón Sánchez, Pablo; Favot, Laurent; Cody, George; Steele, Andrew; Flückiger, Lorenzo; Lees, David; Nefian, Ara; Martin, Mildred; Gailhanou, Marc; Westall, Frances; Israël, Guy; Agard, Christophe; Baroukh, Julien; Donny, Christophe; Gaboriaud, Alain; Guillemot, Philippe; Lafaille, Vivian; Lorigny, Eric; Paillet, Alexis; Pérez, René; Saccoccio, Muriel; Yana, Charles; Aparicio, Carlos Armiens; Caride Rodríguez, Javier; Carrasco Blázquez, Isaías; Gómez Gómez, Felipe; Elvira, Javier Gómez; Hettrich, Sebastian; Lepinette Malvitte, Alain; Marín Jiménez, Mercedes; Frías, Jesús Martínez; Soler, Javier Martín; Torres, F. Javier Martín; Molina Jurado, Antonio; Sotomayor, Luis Mora; Muñoz Caro, Guillermo; Navarro López, Sara; González, Verónica Peinado; García, Jorge Pla; Rodriguez Manfredi, José Antonio; Planelló, Julio José Romeral; Alejandra Sans Fuentes, Sara; Sebastian Martinez, Eduardo; Torres Redondo, Josefina; O'Callaghan, Roser Urqui; Zorzano Mier, María-Paz; Chipera, Steve; Lacour, Jean-Luc; Mauchien, Patrick; Sirven, Jean-Baptiste; Manning, Heidi; Fairén, Alberto; Hayes, Alexander; Joseph, Jonathan; Squyres, Steven; Thomas, Peter; Dupont, Audrey; Lundberg, Angela; Melikechi, Noureddine; Mezzacappa, Alissa; DeMarines, Julia; Grinspoon, David; Reitz, Günther; Prats, Benito; Atlaskin, Evgeny; Genzer, Maria; Harri, Ari-Matti; Haukka, Harri; Kahanpää, Henrik; Kauhanen, Janne; Paton, Mark; Polkko, Jouni; Schmidt, Walter; Siili, Tero; Fabre, Cécile; Wray, James; Wilhelm, Mary Beth; Poitrasson, Franck; Patel, Kiran; Gorevan, Stephen; Indyk, Stephen; Paulsen, Gale; Bish, David; Schieber, Juergen; Gondet, Brigitte; Langevin, Yves; Geffroy, Claude; Baratoux, David; Berger, Gilles; Cros, Alain; Uston, Claude d.; Lasue, Jérémie; Lee, Qiu-Mei; Meslin, Pierre-Yves; Pallier, Etienne; Parot, Yann; Pinet, Patrick; Schröder, Susanne; Toplis, Mike; Lewin, Éric; Brunner, Will; Heydari, Ezat; Achilles, Cherie; Oehler, Dorothy; Sutter, Brad; Cabane, Michel; Coscia, David; Szopa, Cyril; Robert, François; Sautter, Violaine; Nachon, Marion; Buch, Arnaud; Stalport, Fabien; Coll, Patrice; François, Pascaline; Raulin, François; Teinturier, Samuel; Cameron, James; Clegg, Sam; Cousin, Agnès; DeLapp, Dorothea; Dingler, Robert; Jackson, Ryan Steele; Johnstone, Stephen; Lanza, Nina; Little, Cynthia; Nelson, Tony; Williams, Richard B.; Jones, Andrea; Kirkland, Laurel; Treiman, Allan; Baker, Burt; Cantor, Bruce; Caplinger, Michael; Davis, Scott; Duston, Brian; Fay, Donald; Hardgrove, Craig; Harker, David; Herrera, Paul; Jensen, Elsa; Kennedy, Megan R.; Krezoski, Gillian; Krysak, Daniel; Lipkaman, Leslie; McCartney, Elaina; McNair, Sean; Nixon, Brian; Posiolova, Liliya; Ravine, Michael; Salamon, Andrew; Saper, Lee; Stoiber, Kevin; Supulver, Kimberley; Van Beek, Jason; Zimdar, Robert; French, Katherine Louise; Iagnemma, Karl; Miller, Kristen; Summons, Roger; Goesmann, Fred; Hviid, Stubbe; Johnson, Micah; Lefavor, Matthew; Lyness, Eric; Breves, Elly; Dyar, M. Darby; Fassett, Caleb; Blake, David F.; Bristow, Thomas; DesMarais, David; Edwards, Laurence; Haberle, Robert; Hoehler, Tori; Hollingsworth, Jeff; Kahre, Melinda; Keely, Leslie; McKay, Christopher; Bleacher, Lora; Brinckerhoff, William; Choi, David; Conrad, Pamela; Dworkin, Jason P.; Eigenbrode, Jennifer; Floyd, Melissa; Freissinet, Caroline; Garvin, James; Glavin, Daniel; Harpold, Daniel; Mahaffy, Paul; Martin, David K.; McAdam, Amy; Pavlov, Alexander; Raaen, Eric; Smith, Michael D.; Stern, Jennifer; Tan, Florence; Trainer, Melissa; Meyer, Michael; Posner, Arik; Voytek, Mary; Anderson, Robert C.; Aubrey, Andrew; Beegle, Luther W.; Behar, Alberto; Brinza, David; Calef, Fred; Christensen, Lance; Crisp, Joy A.; DeFlores, Lauren; Feldman, Jason; Feldman, Sabrina; Flesch, Gregory; Hurowitz, Joel; Jun, Insoo; Keymeulen, Didier; Maki, Justin; Mischna, Michael; Morookian, John Michael; Parker, Timothy; Pavri, Betina; Schoppers, Marcel; Sengstacken, Aaron; Simmonds, John J.; Spanovich, Nicole; de la Torre Juarez, Manuel; Vasavada, Ashwin R.; Webster, Christopher R.; Yen, Albert; Archer, Paul Douglas; Cucinotta, Francis; Jones, John H.; Ming, Douglas; Morris, Richard V.; Niles, Paul; Rampe, Elizabeth; Nolan, Thomas; Fisk, Martin; Radziemski, Leon; Barraclough, Bruce; Bender, Steve; Berman, Daniel; Dobrea, Eldar Noe; Tokar, Robert; Vaniman, David; Leshin, Laurie; Cleghorn, Timothy; Huntress, Wesley; Manhès, Gérard; Hudgins, Judy; Olson, Timothy; Stewart, Noel; Sarrazin, Philippe; Grant, John; Vicenzi, Edward; Wilson, Sharon A.; Bullock, Mark; Ehresmann, Bent; Hamilton, Victoria; Hassler, Donald; Peterson, Joseph; Rafkin, Scot; Zeitlin, Cary; Fedosov, Fedor; Golovin, Dmitry; Karpushkina, Natalya; Kozyrev, Alexander; Litvak, Maxim; Malakhov, Alexey; Mitrofanov, Igor; Mokrousov, Maxim; Nikiforov, Sergey; Prokhorov, Vasily; Sanin, Anton; Tretyakov, Vladislav; Varenikov, Alexey; Vostrukhin, Andrey; Kuzmin, Ruslan; Clark, Benton; Wolff, Michael; McLennan, Scott; Botta, Oliver; Drake, Darrell; Bean, Keri; Lemmon, Mark; Lee, Ella Mae; Sucharski, Robert; Hernández, Miguel Ángel de Pablo; Blanco Ávalos, Juan José; Ramos, Miguel; Kim, Myung-Hee; Malespin, Charles; Plante, Ianik; Muller, Jan-Peter; González, Rafael Navarro; Ewing, Ryan; Boynton, William; Downs, Robert; Fitzgibbon, Mike; Harshman, Karl; Morrison, Shaunna; Kortmann, Onno; Williams, Amy; Lugmair, Günter; Wilson, Michael A.; Jakosky, Bruce; Zunic, Tonci Balic; Frydenvang, Jens; Kinch, Kjartan; Stipp, Susan Louise Svane; Boyd, Nick; Campbell, John L.; Gellert, Ralf; Perrett, Glynis; Pradler, Irina; VanBommel, Scott; Jacob, Samantha; Owen, Tobias; Rowland, Scott; Savijärvi, Hannu; Boehm, Eckart; Böttcher, Stephan; Burmeister, Sönke; Guo, Jingnan; Köhler, Jan; García, César Martín; Mellin, Reinhold Mueller; Schweingruber, Robert Wimmer; McConnochie, Timothy; Benna, Mehdi; Franz, Heather; Bower, Hannah; Brunner, Anna; Blau, Hannah; Boucher, Thomas; Carmosino, Marco; Atreya, Sushil; Elliott, Harvey; Halleaux, Douglas; Rennó, Nilton; Wong, Michael; Pepin, Robert; Elliott, Beverley; Spray, John; Thompson, Lucy; Gordon, Suzanne; Williams, Joshua; Vasconcelos, Paulo; Bentz, Jennifer; Nealson, Kenneth; Popa, Radu; Moersch, Jeffrey; Tate, Christopher; Day, Mackenzie; Kocurek, Gary; Hallet, Bernard; Sletten, Ronald; Francis, Raymond; McCullough, Emily; Cloutis, Ed; ten Kate, Inge Loes; Arvidson, Raymond; Fraeman, Abigail; Scholes, Daniel; Slavney, Susan; Stein, Thomas; Ward, Jennifer; Berger, Jeffrey; Moores, John E.

    2013-05-01

    Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

  4. Contemporary Conceptual Approaches in Fluvial Geomorphology

    Directory of Open Access Journals (Sweden)

    Mônica dos Santos Marçal

    2016-06-01

    Full Text Available Contemporary fluvial geomorphology faces challenging questions, especially as it goes by understanding the Late Holocene/Anthropocene period, which has repercussions today and are intrinsically important to understand the human river disturbance. Given the scale that physical rates operate in complex river systems, two conceptual paths were developed to analyze the spatial and temporal organization. The network view emphasizes controls on catchment-scale and a reach approach focuses on discontinuity and local controls. Fluvial geomorphology has seek to understand the organization of complex river systems from the integrated view of the continuity and discontinuity paradigm. This integrated approach has stimulated within the geomorphology, the emergence of new theoretical-methodological instruments. It is recognized that rivers management is an ongoing process, part of the socio-cultural development, which refers to both a social movement and scientific exercise.

  5. Natural radionuclide behaviour in the fluvial environment

    International Nuclear Information System (INIS)

    Murray, A.S.; Olley, J.M.; Wallbrink, P.J.

    1992-01-01

    Variable concentrations of uranium and thorium series nuclides and 7 Be have been measured in soils and sediments. Strong correlations between 226 Ra and thorium series nuclides were found in sediments but not in soils. Laboratory measurements suggest the correlations arise from particle size and density dependent transport, and transport-related abrasion of iron oxide coatings. These correlations are characteristic of the sampled location, and provide a method for identifying the source areas which dominate the fluvial nuclide flux, and by implication, the associated sediment flux. Cosmogenic 7 Be (half-life 53 d) also contributes to nuclide fluxes. Over an 18 month period, individual rainstorms increased the 7 Be soil inventory by 10% on average. Dry precipitation contributed less than 10% to the total. Most 7 Be was retained within the top few millimetres of soil. It is deduced that 7 Be presence in fluvial sediments indicates a significant surface source contribution to the overall nuclide and sediment flux. (author)

  6. Current Status of Single-incision Laparoscopic Surgery

    DEFF Research Database (Denmark)

    Ahmed, Irfan; Ciancio, Fabio; Ferrara, Vincenzo

    2012-01-01

    Recent advances in minimally invasive surgery have centered on reducing the number of incisions required, which has led to the development of the single-incision laparoscopic technique. A panel of European single-incision laparoscopy experts met to discuss the current status of, and the future...

  7. Higher Incision at Upper Part of Lower Segment Caesarean Section

    Directory of Open Access Journals (Sweden)

    Yong Shao

    2014-06-01

    Conclusions: An incision at the upper part of the lower segment reduces blood loss, enhances uterine retraction, predisposes to fewer complications, is easier to repair, precludes bladder adhesion to the suture line and reduces operation time. Keywords: caesarean section; higher incision technique; traditional uterine incision technique.

  8. Drainage development and incision rates in an Upper Pleistocene Basalt-Limestone Boundary Channel: The Sa'ar Stream, Golan Heights, Israel

    Science.gov (United States)

    Shtober-Zisu, N.; Inbar, M.; Mor, D.; Jicha, B. R.; Singer, B. S.

    2018-02-01

    Long-term fluvial incision processes and corresponding geomorphic evolution are difficult to quantify, especially in complex systems affected by lithological and tectonic factors. Volcanic landscapes offer the most appropriate environment for the study of landscape evolution, as there is a clear starting time of formation and the lithology is homogenous. In the present study we aim to: (1) analyse the interplay of construction and incision processes throughout eruptive activity; (2) study fluvial erosion processes; (3) analyse sedimentary and volcanic lithological responses to channel erosion; and (4) calculate the incision rates in young basaltic bedrock. We have integrated existing and new 40Ar/39Ar ages of lava flows with estimates of channel geometry and tectonic activity, and considered process geomorphology concepts, to fully understand evolution of a bedrock channel incised at the boundary between basalts and sedimentary rocks with coeval active volcanic processes forcing drainage evolution. Our findings indicate that the Sa'ar basin evolution is controlled by: (1) rock strength of the mixed lithology; (2) alternating cycles of volcanic activity followed by erosion and incision; and (3) the Plio-Pleistocene uplift of Mt. Hermon. The carbonate slopes composing the southern flank of Mt. Hermon are moderate (18-26%) while the basalt slopes deriving from the Golan Heights are much steeper (26-51%). The highly erodible sedimentary rocks at Mt. Hermon's piedmont accelerated river incision, shaping a 650 m wide by 100 m deep canyon. Inside the canyon, the steep channel slope (8.6%) enables downstream movement of large boulders, including autochthonous mega-blocks (D90 size > 2.5 m); 24 knickpoints were identified using DS plots, developed within a knick zone over a distance of 6 km. The brittle and porous structure of the rubbly and blocky interflow layers (clinkers), interbedded between two massive basalt flows, enhances erosion and accelerates scouring of the

  9. Incision and Landsliding Lead to Coupled Increase in Sediment Flux and Grain Size Export

    Science.gov (United States)

    Roda-Boluda, D. C.; Brooke, S.; D'Arcy, M. K.; Whittaker, A. C.; Armitage, J. J.

    2017-12-01

    The rates and grain sizes of sediment fluxes modulate the dynamics and timing of landscape response to tectonics, and dictate the depositional patterns of sediment in basins. Over the last decades, we have gained a good quantitative understanding on how sediment flux and grain size may affect incision and basin stratigraphy. However, we comparably still have limited knowledge on how these variables change with varying tectonic rates. To address this question, we have studied 152 catchments along 8 normal fault-bounded ranges in southern Italy, which are affected by varying fault slip rates and experiencing a transient response to tectonics. Using a data set of 38 new and published 10Be erosion rates, we calibrate a sediment flux predictive equation (BQART), in order to estimate catchment sediment fluxes. We demonstrate that long-term sediment flux is governed by fault slip rates and the tectonically-controlled transient incision, and that sediment flux estimates from the BQART, steady-state assumptions, and incised volumes are highly correlated. This is supported by our 10Be erosion rates, which are controlled by fault slip and incision rates, and the associated landsliding. Based on a new landslide inventory, we show that erosion rate differences are likely due to differences in incision-related landslide activity across these catchments, and that landslides are a major component of sediment fluxes. From a data set of >13000 grain size counts on hillslope grain size supply and fluvial sediment at catchment outlets, we observe that landslides deliver material 20-200% coarser than other sediment sources, and that this coarse supply has an impact on the grain size distributions being exported from the catchments. Combining our sediment flux and grain size data sets, we are able to show that for our catchments, and potentially also for any areas that respond to changes in climate or tectonics via enhanced landsliding, sediment flux and grain size export increase

  10. Incisiones verticales en SARPE Vertical incisions in SARPE

    Directory of Open Access Journals (Sweden)

    J. Gonzalez Lagunas

    2005-06-01

    Full Text Available La expansión rápida de paladar asistida quirúrgicamente (SARPE es una de las opciones terapeuticas de los transtornos transversales del maxilar superior. Presentamos nuestra experiencia inicial con una variante técnica consistente en una corticotomía de la pared lateral del maxilar combinada con una osteotomía palatina media transincisal, y efectuadas a través de tres pequeñas incisiones verticales.Surgically assisted rapid palatal expansion (SARPE is one of the therapeutic options for the correction of transverse maxillary collapse. We present our initial experience with a technique consisting in a lateral corticotomy of the maxilla plus a transincisal midpalatal osteotomy, both performed through minimal vertical incisions.

  11. A Late Pleistocene linear dune dam record of aeolian-fluvial dynamics at the fringes of the northwestern Negev dunefield

    Science.gov (United States)

    Roskin, Joel; Bookman, Revital; Friesem, David; Vardi, Jacob

    2017-04-01

    maintenance by smaller sand mobilization events. Wetter climates increased flood events boosting LFFD buildup rates but shortened dune dam longevity. The abundance and recurrence of water bodies in middle and large basins deteriorated after Harifian times when reduced wind power during the post-Younger Dryas constrained dune dam maintenance. Eventually, dune dam incision began as a result of overland flow after accommodation space dissipated due to LFFD accretion. Altogether, fluctuating high wind power and precipitation during a glacial-interglacial time window and high availability of fine-grained fluvial sediment yield from eroded middle to late Pleistocene upstream highlands loess mantles, combined to create a trio of aeolian-fluvial forcing factors supporting short-term but amplified dune-dammed fluvial depositional conditions.

  12. Small incision guarded hydroaspiration of iris lesions.

    Science.gov (United States)

    Singh, Arun D

    2017-11-01

    To describe the technique and results of a minimally invasive surgical technique for resection of small iris lesions. Consecutive case series of 22 patients with localised, small iris lesions that were resected using the described surgical technique that composed of multiple, small corneal incisions created to allow for internal iris resection with 23-gauge horizontal vitrectomy scissors, followed by guarded tumour aspiration through a clear plastic tubing (diameter 3.5 mm) primed with viscoelastic agent. The mean largest basal diameter was 3.0 mm (range 1.5-5.0 mm; median 3.0 mm) and mean thickness was 1.3 mm (range 0.5-2.5 mm; median 1.0 mm). Use of multiple (2-4) small corneal incisions (range 2.0-3.0 mm; mean 2.8 mm) allowed reduced postoperative morbidity (significant hyphema (0%), hypotony (0%), wound leak (0%), >2 line change in best corrected visual acuity at postoperative 1 week (4.5%) and mean corneal astigmatism of 1.0 D (range 0.14-2.99 D; median 0.8 D) at postoperative 4-12 weeks. The tumour could be resected with clear surgical margins in all neoplastic cases (benign (2), borderline (1) and malignant (16)). Local recurrence or metastases were not observed in any melanoma case over a mean follow-up of 33.0 months (range 1.0-90.0 months; median 33.5 months). Small incision guarded hydroaspiration is a minimally invasive surgical technique for resection of select small iris lesions. Use of multiple small corneal incisions avoids morbidity associated with a single large corneoscleral incision, and use of guarded aspiration may eliminate the risk of wound contamination by the malignant tumour. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  13. The evolution of a colluvial hollow to a fluvial channel with periodic steps following two transformational disturbances: A wildfire and a historic flood

    Science.gov (United States)

    Rengers, Francis K.; McGuire, Luke; Ebel, Brian A.; Tucker, G. E.

    2018-01-01

    The transition of a colluvial hollow to a fluvial channel with discrete steps was observed after two landscape-scale disturbances. The first disturbance, a high-severity wildfire, changed the catchment hydrology to favor overland flow, which incised a colluvial hollow, creating a channel in the same location. This incised channel became armored with cobbles and boulders following repeated post-wildfire overland flow events. Three years after the fire, a record rainstorm produced regional flooding and generated sufficient fluvial erosion and sorting to produce a fluvial channel with periodically spaced steps. An analysis of the step spacing shows that after the flood, newly formed steps retained a similar spacing to the topographic roughness spacing in the original colluvial hollow (prior to channelization). This suggests that despite a distinct change in channel form roughness and bedform morphology, the endogenous roughness periodicity was conserved. Variations in sediment erodibility helped to create the emergent steps as the largest particles ( >D84) remained immobile, becoming step features, and downstream soil was easily winnowed away.

  14. The evolution of a colluvial hollow to a fluvial channel with periodic steps following two transformational disturbances: A wildfire and a historic flood

    Science.gov (United States)

    Rengers, F. K.; McGuire, L. A.; Ebel, B. A.; Tucker, G. E.

    2018-05-01

    The transition of a colluvial hollow to a fluvial channel with discrete steps was observed after two landscape-scale disturbances. The first disturbance, a high-severity wildfire, changed the catchment hydrology to favor overland flow, which incised a colluvial hollow, creating a channel in the same location. This incised channel became armored with cobbles and boulders following repeated post-wildfire overland flow events. Three years after the fire, a record rainstorm produced regional flooding and generated sufficient fluvial erosion and sorting to produce a fluvial channel with periodically spaced steps. An analysis of the step spacing shows that after the flood, newly formed steps retained a similar spacing to the topographic roughness spacing in the original colluvial hollow (prior to channelization). This suggests that despite a distinct change in channel form roughness and bedform morphology, the endogenous roughness periodicity was conserved. Variations in sediment erodibility helped to create the emergent steps as the largest particles (>D84) remained immobile, becoming step features, and downstream soil was easily winnowed away.

  15. Do river channels decrease in width downstream on Distributive Fluvial Systems? An evaluation of modern mega-fans

    Science.gov (United States)

    Espinoza, T. N.; Scuderi, L. A.; Weissmann, G. S.; Hartley, A. J.

    2014-12-01

    Recent studies on aggradational continental sedimentary basins globally show that fluvial deposits in most modern sedimentary basins are dominated Distributive Fluvial Systems (DFS). DFS's are identified by: (1) pattern of channels and floodplain deposits that radiate outward from an apex located where the river enters the sedimentary basin, (2) deposition where an alluvial system becomes unconfined upon entering the sedimentary basin, (3) broadly fan shaped deposit that is convex upward across the DFS and concave upward down-fan, and (4) if the DFS is incised, an intersection point above which the alluvial system is held in an incised valley and below which it distributes sediment across an active depositional lobe. Several papers about DFS hypothesized that rivers on DFS decrease in size down-fan. We are testing this hypothesis through evaluation of LANDSAT and STRM data from large DFS described by Hartley et al (2010). We use ArcGIS to: (1) open the images and merge them together if there are more than one image corresponding to the DFS being studied, (2) use a Maximum Likelihood Analysis in six classes to segment different features on the DFS (e.g. exposed sands, water, vegetation, and other fan environments), (3) isolate the classes that correspond to the active channel belt (e.g., exposed sand bars and water), (4) divide the active channel belt into 1000 m long sections, (5) determine the area of active channel belt in each section, and (6) calculate the average width of the river in each section (e.g., W = area/1000m). We present our result for each DFS river on a graph that shows the change in width downstream. Our final product will be a dataset that contains width versus distance down-fan from the apex for as many of the large DFS from Hartley et al (2010) as possible. If the hypothesis is supported, the decrease in width could have a substantial predictive significance on sandstone geometry in fluvial successions.

  16. Quaternary river incision in the uplifted Rhenish massif (Ardennes, Belgium) - Insights from 10Be/26Al dating of river terraces

    Science.gov (United States)

    Rixhon, Gilles; Bourlès, Didier; Braucher, Régis; Siame, Lionel; Bovy, Benoît.; Demoulin, Alain

    2010-05-01

    Although it constitutes the main tool to unravel the regional recent tectonics, the chronology of the Pleistocene river incision is still poorly constrained within the uplifted Rhenish-Ardennes massif (Belgium, western Europe). Here, we measure cosmogenic nuclides concentrations (10Be and 26Al) in terrace quartz or quartzite sediments of several Ardennian rivers (Meuse, Ourthe and Amblève) in order to date the so-called Younger Main Terrace (YMT), a key-level in the network evolution. Though these dating methods are successfully used to determine ages of superficial (e.g., glacial) deposits, dating of fluvial terraces remains difficult. Possible predepositional exposures of the sampled material (inherited 10Be and 26Al) may indeed bias the measurements towards higher nuclide concentrations while several postdepositional processes (burial, erosion) may cause a lowering of the 10Be and 26Al concentrations. In an attempt to overcome these difficulties, the selected fluvial deposits (five locations) were sampled using a profiling technique on as thick as possible sections (more than 3 m). We present the first absolute dating of the YMT in the lower Meuse valley (nearby the Dutch boundary), where we obtained an age of 630 ka for a terrace deposit buried beneath 3 m of Weichselian loess. This age is consistent with some previously published estimates based on paleomagnetic data and MIS correlations. However, our ages for the same terrace level within the Ardennes are significantly younger: >400 ka in the lower Ourthe, and only ~220 ka still farther upstream, in the lower Amblève. We thus demonstrate that the post-YMT incision occurred diachronically in NE Ardennes. The ~0.5 Ma timespan needed by the erosion wave to propagate from the lower Meuse towards the Ardennian headwaters contradicts the long-held statement of a climatically driven incision that would have been synchronous throughout the catchment.

  17. Vision for a worldwide fluvial-sediment information network

    Science.gov (United States)

    Gray, J.R.; Osterkamp, W.R.

    2007-01-01

    The nations of the world suffer both from the deleterious effects of some natural and human-altered fluxes of fluvial sediment and a lack of consistent and reliable information on the temporal and spatial occurrence of fluvial sediments. Decades ago, this difficulty was unavoidable due to a lack of understanding of the magnitude and scope of environmental influences exerted by fluvial sediment coupled with a dearth of tools for monitoring and studying the data. Such is no longer the case.

  18. Linking bedrock exhumation, fluvial terraces, and geomorphic indices to constrain deformation rates at multiple timescales across the Himalayan deformation front in the Kashmir Himalaya, northwest India.

    Science.gov (United States)

    Gavillot, Y. G.

    2017-12-01

    In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline, and displays no major emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the Suruin-Mastargh anticline hampers quantifying the earthquake potential for the deformation front. Our study combines bedrock exhumation, folded fluvial terraces, long-river profiles and river incision (specific stream power) analyses across the deformation front. At the core of the frontal fold, Apatite (U-Th)/He (AHe) cooling ages of detrital grains from the Siwalik foreland sediments indicate significant resetting. AHe data and thermal modeling reveal rapid cooling and exhumation initiated ca. 4 Ma for the deformation front, at least 3 Ma earlier than is indicated from previously available data. Exhumation rates over the last 1 m.y. and 4 m.y. range from 0.5 - 2.4 mm/yr, and 0.5 - 1 mm/yr, respectively. Four fluvial terraces yield multiple OSL and depth profiles Be10 TCN ages between 53 ka and 0.4 ka. Vector fold restoration of long terrace profiles, calculated specific stream power values, bedrock dip data, and stratigraphic thickness indicate a deformation pattern controlled by a duplex structure emplaced at depth along the basal décollement, folding the overlying roof thrust and foreland strata into a detachment-like fold. Dated terraces across the frontal fold yield rock uplift and shortening rates that range between 1.8-2.5 mm/yr, and 3.8-5.4 mm/yr, respectively, since 53 ka. Similarly, a balanced cross section yields a long-term shortening rate of 5mm mm/yr since 4 Ma. Geodetic data indicate that an 11-12 mm/yr arc-normal shortening rate characterizes the interseismic strain accumulation across the plate boundary due to India-Tibet convergence. These data combined with rates of other active internal faults in the Kashmir Himalaya indicate that shortening occurs roughly at an equal rate between folding at

  19. Comparison of electrocautery incision with scalpel incision in midline abdominal surgery - A double blind randomized controlled trial.

    Science.gov (United States)

    Prakash, Lalgudi Dorairajan; Balaji, Nitesh; Kumar, Sathasivam Suresh; Kate, Vikram

    2015-07-01

    To compare the electrocautery incision with scalpel incision in patients undergoing abdominal surgery using a midline incision with respect to incision time, blood loss during incision, postoperative incision site pain and wound infection. Patients undergoing midline abdominal surgery were randomized into electrocautery and scalpel groups. The incision dimensions, incision time and blood loss during incision were noted intraoperatively. Postoperative pain and wound infection were recorded on every postoperative day for one week. 41 patients in each of the two groups were analyzed. Gender and age distribution was similar in both the groups. The mean incision time per unit wound area in the electrocautery group and scalpel group was 9.40 ± 3.37 s/cm(2) and 9.07 ± 3.40 s/cm(2) (p = 0.87) respectively. The mean blood loss per unit wound area was significantly lower in the electrocautery group at 6.46 ± 3.94 ml when compared to that of 23.40 ± 15.28 ml in the scalpel group (p= electrocautery and scalpel groups (14.63% vs. 12.19%; p = 0.347). With a comparable Postoperative incision site pain, wound infection rate and significantly lower blood loss with the equal time taken for the incision, electrocautery can be considered safe and effective in making skin incision in midline laparotomy compared to scalpel incision. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

  20. Fluvial geomorphology and river engineering: future roles utilizing a fluvial hydrosystems framework

    Science.gov (United States)

    Gilvear, David J.

    1999-12-01

    River engineering is coming under increasing public scrutiny given failures to prevent flood hazards and economic and environmental concerns. This paper reviews the contribution that fluvial geomorphology can make in the future to river engineering. In particular, it highlights the need for fluvial geomorphology to be an integral part in engineering projects, that is, to be integral to the planning, implementation, and post-project appraisal stages of engineering projects. It should be proactive rather than reactive. Areas in which geomorphologists will increasingly be able to complement engineers in river management include risk and environmental impact assessment, floodplain planning, river audits, determination of instream flow needs, river restoration, and design of ecologically acceptable channels and structures. There are four key contributions that fluvial geomorphology can make to the engineering profession with regard to river and floodplain management: to promote recognition of lateral, vertical, and downstream connectivity in the fluvial system and the inter-relationships between river planform, profile, and cross-section; to stress the importance of understanding fluvial history and chronology over a range of time scales, and recognizing the significance of both palaeo and active landforms and deposits as indicators of levels of landscape stability; to highlight the sensitivity of geomorphic systems to environmental disturbances and change, especially when close to geomorphic thresholds, and the dynamics of the natural systems; and to demonstrate the importance of landforms and processes in controlling and defining fluvial biotopes and to thus promote ecologically acceptable engineering. Challenges facing fluvial geomorphology include: gaining full acceptance by the engineering profession; widespread utilization of new technologies including GPS, GIS, image analysis of satellite and airborne remote sensing data, computer-based hydraulic modeling and

  1. Electrocautery skin incision for neurosurgery procedures--technical note.

    Science.gov (United States)

    Nitta, Naoki; Fukami, Tadateru; Nozaki, Kazuhiko

    2011-01-01

    The reluctance to incise skin with electrocautery is partly attributable to concerns about excessive scarring and poor wound healing. However, recently no difference was reported in wound complications between the cold scalpel and electrocautery scalpel. We assessed the safety and efficacy of electrocautery skin incision in 22 scalp incisions, including 4 cases of reoperation. Electrocautery skin incisions were created using a sharp needle electrode. The generator unit was set on cutting mode, with power of 6 W and 330 kHz sinusoid waveform. Subcutaneous dissections also used the sharp needle electrode, set on coagulating mode, with power of 10 W and 1 MHz pulse-modulated waveform. Galea incisions used a standard blade tip, set on coagulating mode, with power of 20 W and 1 MHz pulse-modulated waveform. Skin incision with the sharp needle electrode caused no charring of the wound. Little bleeding or oozing were observed and skin clips were not necessary. No wound complication such as necrosis or infection occurred. Electrocautery skin incisions for re-operations were also performed safely without complications. Electrocautery skin incision is sufficiently safe procedure not only for first operation but also for re-operation. Electrocautery skin incision is efficacious, especially for extended operation times, because of little blood loss from the edges of skin incision and possible avoidance of skin edge necrosis or alopecia caused by skin clips.

  2. A single incision transaxillary thoracoscopic sympathectomy

    Directory of Open Access Journals (Sweden)

    Marić Nebojša

    2014-01-01

    Full Text Available Background/Aim. Primary hyperhidrosis causes are unknown. The disorder begins in early childhood. It intensifies in puberty and maturity. It is equally present in both sexes. The symptoms exacerbate when the body temperature rises and due to emotional stimuli affecting the sympathetic nerve system. The aim of this study was to demonstrate that videoassisted thoracoscopic surgery (VATS sympathectomy is a method for primary focal hyperhidrosis permanent treatment. The single incision method in properly selected patients maximizes the intervention effectiveness and minimizes aesthetic side effects. Methods. This prospective study analysed the findings in patients who had been operated on due to primary focal hyperhidrosis (face, palms, and armpits using a single small transaxilarry incision in the third inter-rib space at the level of the anterior axillary line with two 5 mm flexible ports. All the patients, with T2-T5 thoracoscopic sympathectomy of the sympathetic chain using a single small incision in the third inter-rib space in the anterior axillary line, were analysed in the period from September 2009 to November 2010 regarding the postoperative morbidity and outcomes of the operation (clinical evaluation and visual analogue scale with a view to assessing the effectiveness of the surgery conducted in this manner. Results. A total of 47 patients (18 men, 29 women, 18 to 48 years old (29 on average had underwent 94 bilateral video-assisted thoracoscopic sympathectomies. The sympathectomy was indicated in cases of facial blushing and sweating (6.38%, palmary sweating (34.04%, axillary sweating (14.89% or both palmary and axillary sweating (44.68%. The largest percentage of patients (98.6% had left the hospital the following day. The postoperative 30 day’s mortality was 0 and the conversion into open surgery was not necessary. As for complications, there had been an occurrence of partial pneumothorax in two patients treated by means of

  3. Small-incision lenticule extraction (SMILE)

    DEFF Research Database (Denmark)

    Hansen, Rasmus Søgaard; Lyhne, Niels; Grauslund, Jakob

    2016-01-01

    surgery was 0.07 ± 0.03 (logMAR). However, 12 eyes (1.6 %) lost 2 or more lines of CDVA from before surgery to 3 months postoperatively. Simultaneous treatment of up to 3.00 D of astigmatism was not associated with less predictable refractive outcomes. CONCLUSIONS: In the short term, SMILE seemed......PURPOSE: To study the outcomes of small-incision lenticule extraction (SMILE) for treatment of myopia and myopic astigmatism. METHODS: Retrospective study of patients treated for myopia or myopic astigmatism with SMILE, using a VisuMax(®) femtosecond laser (Carl Zeiss Meditec, Jena, Germany...

  4. Fluvial processes on Mars: Erosion and sedimentation

    Science.gov (United States)

    Squyres, Steven W.

    1988-01-01

    One of the most important discoveries of the Mariner 9 and Viking missions to Mars was evidence of change of the Martian surface by the action of liquid water. From the standpoint of a Mars Rover/Sample Return Mission, fluvial activity on Mars is important in two ways: (1) channel formation has deeply eroded the Martian crust, providing access to relatively undisturbed subsurface units; and (2) much of the material eroded from channels may have been deposited in standing bodies of liquid water. The most striking fluvial erosion features on Mars are the outflow channels. A second type of channel apparently caused by flow of liquid water is the valley systems. These are similar to terrestial drainage systems. The sedimentary deposits of outflow channels are often difficult to identfy. No obvious deposits such as deltaic accumulations are visible in Viking images. Another set of deposits that may be water lain and that date approx. from the epoch of outflow channels are the layered deposits in the Valles Marineris. From the standpoint of a Mars Rover/Sample Return mission, the problem with all of these water-lain sediments is their age, or rather the lack of it.

  5. Examining fluvial fish range loss with SDMs

    Science.gov (United States)

    Taylor, Andrew T.; Papeş, Monica; Long, James M.

    2018-01-01

    Fluvial fishes face increased imperilment from anthropogenic activities, but the specific factors contributing most to range declines are often poorly understood. For example, the range of the fluvial‐specialist shoal bass (Micropterus cataractae) continues to decrease, yet how perceived threats have contributed to range loss is largely unknown. We used species distribution models to determine which factors contributed most to shoal bass range loss. We estimated a potential distribution based on natural abiotic factors and a series of currently occupied distributions that incorporated variables characterizing land cover, non‐native species, and river fragmentation intensity (no fragmentation, dams only, and dams and large impoundments). We allowed interspecific relationships between non‐native congeners and shoal bass to vary across fragmentation intensities. Results from the potential distribution model estimated shoal bass presence throughout much of their native basin, whereas models of currently occupied distribution showed that range loss increased as fragmentation intensified. Response curves from models of currently occupied distribution indicated a potential interaction between fragmentation intensity and the relationship between shoal bass and non‐native congeners, wherein non‐natives may be favored at the highest fragmentation intensity. Response curves also suggested that >100 km of interconnected, free‐flowing stream fragments were necessary to support shoal bass presence. Model evaluation, including an independent validation, suggested that models had favorable predictive and discriminative abilities. Similar approaches that use readily available, diverse, geospatial data sets may deliver insights into the biology and conservation needs of other fluvial species facing similar threats.

  6. Morphology of the last subaerial unconformity on a shelf: insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz

    Science.gov (United States)

    Lobo, F. J.; García, M.; Luján, M.; Mendes, I.; Reguera, M. I.; Van Rooij, D.

    2018-02-01

    The main aim of this study is to explore the spatial patterns of the shelf-scale erosional unconformity related to the last glacial maximum (LGM), particularly in terms of the role of underlying geology and the presumed primary influence of sea-level changes. This involved a detailed mapping of the most recent and widespread erosional shelf surface in a sector of the northern margin of the Gulf of Cádiz (northeast Atlantic Ocean) located adjacent to a major fluvial source. A dense network of high-resolution seismic profiles collected in the 1990s and 2013 off the Guadiana River revealed two distinct geomorphological domains on the LGM shelf-scale subaerial surface. The outer domain exhibits a widespread occurrence of erosional truncations, with a rugged, erosional pattern over the most distal shelf setting that evolves landward into a planar unconformity. The inner domain is more extensive and is characterized by the common occurrence of highly reflective, localized mounded seismic facies that laterally evolve into an irregular surface and in places may develop a channelized morphology. Significant fluvial incision is limited to a major straight valley and a secondary distributary channel. A distinct partition of the lowstand surface is documented, and attributed to a well-marked lithological change. A coarse-grained inner shelf comprises underlying lithified coastal deposits, whereas a fine-grained outer shelf is regarded as the uppermost expression of regressive prodeltaic wedges. The influence of regional indurated surfaces is also expressed in (1) the pattern of erosion, this being more patchy on the inner shelf due to lateral changes of erodibility, whereas on the outer shelf it shows laterally continuous bands, owing to different modes of transgressive ravinement; (2) the spatial and temporal variability of fluvial incision. Inner shelf armoring by indurated deposits prevents reoccupation of previously incised valleys.

  7. Flexible single-incision surgery: a fusion technique.

    Science.gov (United States)

    Noguera, José F; Dolz, Carlos; Cuadrado, Angel; Olea, José; García, Juan

    2013-06-01

    The development of natural orifice transluminal endoscopic surgery has led to other techniques, such as single-incision surgery. The use of the flexible endoscope for single-incision surgery paves the way for further refinement of both surgical methods. To describe a new, single-incision surgical technique, namely, flexible single-incision surgery. Assessment of the safety and effectiveness of endoscopic cholecystectomy in a series of 30 patients. This technique consists of a single umbilical incision through which a flexible endoscope is introduced and consists of 2 parallel entry ports that provide access to nonarticulated laparoscopic instruments. The technique was applied in all patients for whom it was prescribed. No general or surgical wound complications were noted. Surgical time was no longer than usual for single-port surgery. Flexible single-incision surgery is a new single-site surgical technique offering the same level of patient safety, with additional advantages for the surgeon at minimal cost.

  8. Single-incision laparoscopic bariatric surgery

    Directory of Open Access Journals (Sweden)

    Huang Chih-Kun

    2011-01-01

    Full Text Available Background: Bariatric surgery has been established as the best option of treatment for morbid obesity. In recent years single-incision laparoscopic surgery (SILS has emerged as another modality of carrying out the bariatric procedures. While SILS represents an advance, its application in morbid obesity at present is limited. In this article, we review the technique and results of SILS in bariatric surgery. Methods: The PubMed database was searched and totally 11 series reporting SILS in bariatric surgery were identified and analyzed. The case reports were excluded. Since 2008, 114 morbidly obese patients receiving SILS bariatric surgeries were reported. Results: The procedures performed included SILS gastric banding, sleeve gastrectomy and gastric bypass. No mortality was reported in the literatures. Sixteen patients (14.05% needed an additional incision for a liver retractor, a trocar or for conversion. Only one complication of wound infection was reported in these series. All the surgeons reported that the patients were highly satisfied with the scar. Conclusion: Because of abundant visceral and subcutaneous fat and multiple comorbidities in morbid obesity, it is more challenging for surgeons to perform the procedures with SILS. It is clear that extensive development of new instruments and technical aspects of these procedures as well as randomized studies to compare them with traditional laparoscopy are essential before these procedures can be utilized in day-to-day clinical practice.

  9. Ephemeral-fluvial sediments as potential hydrocarbon reservoirs. Vol. 1: Sedimentology

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, K.S.

    1994-12-31

    Although reservoirs formed from ephemeral-fluvial sandstones have previously been considered relatively simple, unresolved problems of sandbody correlation and production anomalies demonstrate the need for improved understanding of their internal complexity. Outcropping ephemeral-fluvial systems have been studied in order to determine the main features and processes occurring in sand-rich ephemeral systems and to identify which features will be of importance in a hydrocarbon reservoir. The Lower Jurassic Upper Moenave and Kayenta Formations of south-eastern Utah and northern Arizona comprise series of stacked, sand-dominated sheet-like palaeochannels suggestive of low sinuosity, braided systems. Low subsidence rates and rapid lateral migration rates enabled channels to significantly modify their widths during high discharge. (author)

  10. Human FAN1 promotes strand incision in 5'-flapped DNA complexed with RPA.

    Science.gov (United States)

    Takahashi, Daisuke; Sato, Koichi; Hirayama, Emiko; Takata, Minoru; Kurumizaka, Hitoshi

    2015-09-01

    Fanconi anaemia (FA) is a human infantile recessive disorder. Seventeen FA causal proteins cooperatively function in the DNA interstrand crosslink (ICL) repair pathway. Dual DNA strand incisions around the crosslink are critical steps in ICL repair. FA-associated nuclease 1 (FAN1) is a DNA structure-specific endonuclease that is considered to be involved in DNA incision at the stalled replication fork. Replication protein A (RPA) rapidly assembles on the single-stranded DNA region of the stalled fork. However, the effect of RPA on the FAN1-mediated DNA incision has not been determined. In this study, we purified human FAN1, as a bacterially expressed recombinant protein. FAN1 exhibited robust endonuclease activity with 5'-flapped DNA, which is formed at the stalled replication fork. We found that FAN1 efficiently promoted DNA incision at the proper site of RPA-coated 5'-flapped DNA. Therefore, FAN1 possesses the ability to promote the ICL repair of 5'-flapped DNA covered by RPA. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  11. Fluvial geomorphology on Earth-like planetary surfaces: A review.

    Science.gov (United States)

    Baker, Victor R; Hamilton, Christopher W; Burr, Devon M; Gulick, Virginia C; Komatsu, Goro; Luo, Wei; Rice, James W; Rodriguez, J A P

    2015-09-15

    Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn's moon Titan). In other cases, as on Mercury, Venus, Earth's moon, and Jupiter's moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn's moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry.

  12. Two-Step Incision for Periarterial Sympathectomy of the Hand

    Directory of Open Access Journals (Sweden)

    Seung Bae Jeon

    2015-11-01

    Full Text Available BackgroundSurgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire.MethodsA total of 40 patients (17 men and 23 women with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS and the Wake Forest University rating scale.ResultsThe total patient score was 8.59 (range, 6-15 in the two-step incision group and 9.62 (range, 7-18 in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034 but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03.ConclusionsCompared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.

  13. Tamarix, hydrology and fluvial geomorphology: Chapter 7

    Science.gov (United States)

    Auerbach, Daniel A.; Merritt, David M.; Shafroth, Patrick B.; Sher, Anna A; Quigley, Martin F.

    2013-01-01

    This chapter explores the impact of hydrology and fluvial geomorphology on the distribution and abundance of Tamarix as well as the reciprocal effects of Tamarix on hydrologic and geomorphic conditions. It examines whether flow-regime alteration favors Tamarix establishment over native species, and how Tamarix stands modify processes involved in the narrowing of river channels and the formation of floodplains. It begins with an overview of the basic geomorphic and hydrologic character of rivers in the western United States before analyzing how this setting has contributed to the regional success of Tamarix. It then considers the influence of Tamarix on the hydrogeomorphic form and function of rivers and concludes by discussing how a changing climate, vegetation management, and continued water-resource development affect the future role of Tamarix in these ecosystems.

  14. Glacial vs. Interglacial Period Contrasts in Midlatitude Fluvial Systems, with Examples from Western Europe and the Texas Coastal Plain

    Science.gov (United States)

    Blum, M.

    2001-12-01

    Mixed bedrock-alluvial valleys are the conveyor belts for sediment delivery to passive continental margins. Mapping, stratigraphic and sedimentologic investigations, and development of geochronological frameworks for large midlatitude rivers of this type, in Western Europe and the Texas Coastal Plain, provide for evaluation of fluvial responses to climate change over the last glacial-interglacial period, and the foundations for future quantitative evaluation of long profile evolution, changes through time in flood magnitude, and changes in storage and flux of sediments. This paper focuses on two issues. First, glacial vs. interglacial period fluvial systems are fundamentally different in terms of channel geometry, depositional style, and patterns of sediment storage. Glacial-period systems were dominated by coarse-grained channel belts (braided channels in Europe, large-wavelength meandering in Texas), and lacked fine-grained flood-plain deposits, whereas Holocene units, especially those of late Holocene age, contain appreciable thicknesses of flood-plain facies. Hence, extreme overbank flooding was not significant during the long glacial period, most flood events were contained within bankfull channel perimeters, and fine sediments were bypassed through the system to marine basins. By contrast, extreme overbank floods have been increasingly important during the relatively short Holocene, and a significant volume of fine sediment is sequestered in flood-plain settings. Second, glacial vs. interglacial systems exhibit different amplitudes and frequencies of fluvial adjustment to climate change. High-amplitude but low-frequency adjustments characterized the long glacial period, with 2-3 extended periods of lateral migration and sediment storage puncuated by episodes of valley incision. Low-amplitude but high-frequency adjustments have been more typical of the short Holocene, when there has been little net valley incision or net changes in sediment storage, but

  15. Temporal versus Superior Limbal Incision: Any difference in visual ...

    African Journals Online (AJOL)

    Aim: To compare the visual outcome of a superiorly placed limbal incision with a temporal limbal incision in extracapsular cataract surgery. The main outcome measures are visual acuity and the degree of stigmatism based on refraction. Method: A retrospective non randomized comparative study. Medical records of 40 ...

  16. Transurethral incision of urethral diverticulum in the female

    DEFF Research Database (Denmark)

    Miskowiak, J; Honnens de Lichtenberg, M

    1989-01-01

    A new technique of transurethral incision of urethral diverticulum was successfully used in two women. The method described is safe, simple and shortens operating time.......A new technique of transurethral incision of urethral diverticulum was successfully used in two women. The method described is safe, simple and shortens operating time....

  17. Mini transverse versus longitudinal incision in carpal tunnel syndrome

    International Nuclear Information System (INIS)

    Korkmaz, M.; Cepoglu, M.C.

    2013-01-01

    Objective: To evaluate the effectiveness of mini-transverse compared with mini-longitudinal incision for carpal tunnel release (CTR) with reference to postoperative functional capacity, symptom severity and complication rate. Study Design: Analytical study. Place and Duration of Study: Cumhuriyet University Medical Faculty, Department of Orthopaedics, Tokat State Hospital, Department of Orthopaedics and Medical Park Tokat Hospital, Department of Neurosurgery, from January 2007 to January 2009. Methodology: This study included 93 hands of 79 patients with carpal tunnel syndrome (CTS), which were operated between 2007 and 2009. Patients were divided according to incision types into Group-1 (undergoing mini-longitudinal incision) and Group-2 (undergoing mini-transverse incision). Patients were evaluated initially and at 3 weeks after treatment according to symptom severity and functional status of Boston Questionnaire (BQ). Demographic and clinical data were analyzed and compared statistically between two groups. Results: Statistically significant differences were observed in BQ symptom and functional scores between the pre- and postoperative period (p < 0.0001). BQ symptom and functional scores at postoperative period were better in Group-1 than Group-2 (p = 0.044 and p = 0.023 respectively). The scar hypersensitivity (p = 0.258) and tenderness (p = 1.00) associated with the incision sites were not statistically different. Conclusion: Longitudinal incision is more effective on symptom and functional conditions than transverse incision. However, there was less scar formation with transverse incision. (author)

  18. 100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina

    Science.gov (United States)

    Tofelde, Stefanie; Schildgen, Taylor F.; Savi, Sara; Pingel, Heiko; Wickert, Andrew D.; Bookhagen, Bodo; Wittmann, Hella; Alonso, Ricardo N.; Cottle, John; Strecker, Manfred R.

    2017-09-01

    Fluvial fill terraces in intermontane basins are valuable geomorphic archives that can record tectonically and/or climatically driven changes of the Earth-surface process system. However, often the preservation of fill terrace sequences is incomplete and/or they may form far away from their source areas, complicating the identification of causal links between forcing mechanisms and landscape response, especially over multi-millennial timescales. The intermontane Toro Basin in the southern Central Andes exhibits at least five generations of fluvial terraces that have been sculpted into several-hundred-meter-thick Quaternary valley-fill conglomerates. New surface-exposure dating using nine cosmogenic 10Be depth profiles reveals the successive abandonment of these terraces with a 100 kyr cyclicity between 75 ± 7 and 487 ± 34 ka. Depositional ages of the conglomerates, determined by four 26Al/10Be burial samples and U-Pb zircon ages of three intercalated volcanic ash beds, range from 18 ± 141 to 936 ± 170 ka, indicating that there were multiple cut-and-fill episodes. Although the initial onset of aggradation at ∼1 Ma and the overall net incision since ca. 500 ka can be linked to tectonic processes at the narrow basin outlet, the superimposed 100 kyr cycles of aggradation and incision are best explained by eccentricity-driven climate change. Within these cycles, the onset of river incision can be correlated with global cold periods and enhanced humid phases recorded in paleoclimate archives on the adjacent Bolivian Altiplano, whereas deposition occurred mainly during more arid phases on the Altiplano and global interglacial periods. We suggest that enhanced runoff during global cold phases - due to increased regional precipitation rates, reduced evapotranspiration, or both - resulted in an increased sediment-transport capacity in the Toro Basin, which outweighed any possible increases in upstream sediment supply and thus triggered incision. Compared with two

  19. Water table and overbank flow frequency changes due to suburbanization-induced channel incision, Virginia Coastal Plain, USA

    Science.gov (United States)

    Hancock, G.; Mattell, N.; Christianson, E.; Wacksman, J.

    2004-12-01

    Channel incision is a widely observed response to increased flow in urbanized watersheds, but the effects of channel lowering on riparian water tables is not well documented. In a rapidly incising suburban stream in the Virginia Coastal Plain, we hypothesize that incision has lowered floodplain water tables and decreased the overbank flow frequency, and suggest these changes impact vegetation distribution in a diverse, protected riparian habitat. The monitored stream is a tributary to the James River draining 1.3 km2, of which 15% is impervious cover. Incision has occurred largely through upstream migration of a one m high knickpoint at a rate of 1-2 m/yr, primarily during high flow events. We installed 33 wells in six floodplain transects to assess water table elevations beneath the floodplain adjacent to the incising stream. To document the impacts of incision, two transects are located 30 and 50 m upstream of the knickpoint in unincised floodplain, and the remainder are 5, 30, 70, and 100 m downstream of the knickpoint in incised floodplain. In one transect above and two below, pressure transducers attached to dataloggers provide a high-resolution record of water table response to storm events. Significant differences have been observed in the water table above and below the knickpoint. Above the knickpoint, the water table is relatively flat and is 0.2-0.4 m below the floodplain surface. Water table response to precipitation events is nearly immediate, with the water table rising to the floodplain surface in significant rainfall events. In the transect immediately downstream of the knickpoint, the water table possesses a steep gradient, rising from ~1 m below the floodplain at the stream to 0.3 m below the surface within 20 m. In the most downstream transects, the water table is relatively flat, but is one m below the floodplain surface, equivalent to the depth of incision generated by knickpoint passage. Upstream of the knickpoint, overbank flooding occurs

  20. Incisive canal deflation for correct implant placement: case report.

    Science.gov (United States)

    Spin-Neto, Rubens; Bedran, Telma Blanca Lombardo; de Paula, Wagner Nunes; de Freitas, Rubens Moreno; de Oliveira Ramalho, Lizeti Toledo; Marcantonio, Elcio

    2009-12-01

    This article is a case report of a patient in whom the prosthetic planning indicated the necessity of an incisive canal deflation for the correct installation of an implant that is to be osseointegrated. In the reopening phase after the bone graft installation, the incisive canal deflation (biopsy of its content) was done and titanium implants were installed with one of them invading the anatomical space occupied previously by the incisive canal. The biopsy analysis showed fragments of the incisive artery and nerve, which are responsible for the anterior upper-tooth pulp, the periodontium vascularization and the innervation. From the anastomosis present along with other structures allied with the absence of teeth in the region, there was no detriment to the patient caused by the deflation. Incisive canal deflation is a viable technique in implantology. It can permit ideal prosthetic planning with no detriment to the patient.

  1. Vertical compared with transverse incisions in abdominal surgery

    DEFF Research Database (Denmark)

    Grantcharov, T P; Rosenberg, J

    2001-01-01

    , and late complications (incisional hernia). RESULTS: Eleven randomised controlled trials and seven retrospective studies were identified. The transverse incision offers as good an access to most intra-abdominal structures as a vertical incision. The transverse incision results in significantly less......OBJECTIVE: To reach an evidence-based consensus on the relative merits of vertical and transverse laparotomy incisions. DESIGN: Review of all published randomised controlled trials that compared the postoperative complications after the two main types of abdominal incisions, vertical and transverse....... SETTING: Teaching hospital, Denmark. SUBJECTS: Patients undergoing open abdominal operations. INTERVENTIONS: For some of the variables (burst abdomen and incisional hernia) it was considered adequate to include retrospective studies. Studies were identified through Medline, Cochrane library, Embase...

  2. European Hernia Society guidelines on the closure of abdominal wall incisions

    DEFF Research Database (Denmark)

    Muysoms, F E; Antoniou, S A; Bury, K

    2015-01-01

    using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach and methodological guidance was taken from Scottish Intercollegiate Guidelines Network (SIGN). The literature search included publications up to April 2014. The guidelines were written using the AGREE II...... of rapidly absorbable sutures. It is suggested using a slowly absorbable monofilament suture in a single layer aponeurotic closure technique without separate closure of the peritoneum. A small bites technique with a suture to wound length (SL/WL) ratio at least 4/1 is the current recommended method......, it is suggested using the smallest trocar size adequate for the procedure and closure of the fascial defect if trocars larger or equal to 10 mm are used. For single incision laparoscopic surgery, we suggest meticulous closure of the fascial incision to avoid an increased risk of incisional hernias....

  3. Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Panther, Jennifer L.; Brown, Richard S.; Gaulke, Greggory L.; Woodley, Christa M.; Deters, Katherine A.

    2010-05-11

    In this study, conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District, we measured differences in survival and growth, incision openness, transmitter loss, wound healing, and erythema among abdominal incisions on the linea alba, lateral and parallel to the linea alba (muscle-cutting), and following the underlying muscle fibers (muscle-sparing). A total of 936 juvenile Chinook salmon were implanted with both Juvenile Salmon Acoustic Tracking System transmitters (0.43 g dry) and passive integrated transponder tags. Fish were held at 12°C (n = 468) or 20°C (n = 468) and examined once weekly over 98 days. We found survival and growth did not differ among incision groups or between temperature treatment groups. Incisions on the linea alba had less openness than muscle-cutting and muscle-sparing incisions during the first 14 days when fish were held at 12°C or 20°C. Transmitter loss was not different among incision locations by day 28 when fish were held at 12°C or 20°C. However, incisions on the linea alba had greater transmitter loss than muscle-cutting and muscle-sparing incisions by day 98 at 12°C. Results for wound closure and erythema differed among temperature groups. Results from our study will be used to improve fish-tagging procedures for future studies using acoustic or radio transmitters.

  4. Channel Incision Driven by Suburbanization: Impacts to Riparian Groundwater Flow and Overbank Flow Frequency

    Science.gov (United States)

    Bowles, C. J.; Lawrence, R. L.; Noll, C.; Hancock, G. S.

    2005-12-01

    Channel incision is a widely observed response to increased flow in urbanized watersheds, but the effects of channel lowering on riparian water tables is not well documented. In a rapidly incising suburban stream in the Virginia Coastal Plain, we hypothesize that stream incision has lowered floodplain water tables and decreased the overbank flow frequency. The monitored stream is a tributary to the James River draining 1.3 km2 of which 15% is impervious cover. Incision has occurred largely through upstream migration of a one meter high knickpoint at a rate of ~1.5 m/yr, primarily during high flow events. We installed 63 wells in six stream-perpendicular transects as well as a cluster of wells around the knickpoint to assess water table elevations beneath the floodplain adjacent to the incising stream. Two transects are located 30 and 50 m upstream of the knickpoint in the unincised floodplain, and the remainder are 5, 30, 70, and 100 m downstream in the incised floodplain. In one transect above and two below, pressure transducers attached to dataloggers provide a high-resolution record of water table changes. Erosion pins were installed and channel cross-sections surveyed to determine streambed stability. Significant differences are observed in bank morphology and groundwater flow above vs. below the knickpoint. Above the knickpoint, the banks are stable, ~3 m wide, and ~0.3 m deep, and widen and deepen slightly toward the knickpoint. The water table is relatively flat and is 0.2-0.4 m below the floodplain surface, and groundwater contours suggest flow is parallel to the stream direction. The water table responds immediately to precipitation events, and rises to the floodplain surface in significant rainfall events. Immediately downstream of the knickpoint, channel width increases by about a meter, and stream depth increases to ~1.5 meters. The water table immediately below the knickpoint possesses a steep gradient, and is up to one meter below the floodplain

  5. Excursions in fluvial (dis)continuity

    Science.gov (United States)

    Grant, Gordon E.; O'Connor, James E.; Safran, Elizabeth

    2017-01-01

    Lurking below the twin concepts of connectivity and disconnectivity are their first, and in some ways, richer cousins: continuity and discontinuity. In this paper we explore how continuity and discontinuity represent fundamental and complementary perspectives in fluvial geomorphology, and how these perspectives inform and underlie our conceptions of connectivity in landscapes and rivers. We examine the historical roots of continuum and discontinuum thinking, and how much of our understanding of geomorphology rests on contrasting views of continuity and discontinuity. By continuum thinking we refer to a conception of geomorphic processes as well as geomorphic features that are expressed along continuous gradients without abrupt changes, transitions, or thresholds. Balance of forces, graded streams, and hydraulic geometry are all examples of this perspective. The continuum view has played a prominent role in diverse disciplinary fields, including ecology, paleontology, and evolutionary biology, in large part because it allows us to treat complex phenomena as orderly progressions and invoke or assume equilibrium processes that introduce order and prediction into our sciences.In contrast the discontinuous view is a distinct though complementary conceptual framework that incorporates non-uniform, non-progressive, and non-equilibrium thinking into understanding geomorphic processes and landscapes. We distinguish and discuss examples of three different ways in which discontinuous thinking can be expressed: 1) discontinuous spatial arrangements or singular events; 2) specific process domains generally associated with thresholds, either intrinsic or extrinsic; and 3) physical dynamics or changes in state, again often threshold-linked. In moving beyond the continuous perspective, a fertile set of ideas comes into focus: thresholds, non-equilibrium states, heterogeneity, catastrophe. The range of phenomena that is thereby opened up to scientific exploration similarly expands

  6. Quantifying Quaternary Deformation in the Eastern Cordillera of the Colombian Andes Using Cosmogenic Nuclide Geochronology and Fluvial Geomorphology

    Science.gov (United States)

    Dalman, E.; Taylor, M. H.; Veloza-fajardo, G.; Mora, A.

    2014-12-01

    Northwest South America is actively deforming through the interaction between the Nazca, South American, and Caribbean plates. Though the Colombian Andes are well studied, much uncertainty remains in the rate of Quaternary deformation along the east directed frontal thrust faults hundreds of kilometers in board from the subduction zones. The eastern foothills of the Eastern Cordillera (EC) preserve deformed landforms, allowing us to quantify incision rates. Using 10Be in-situ terrestrial cosmogenic nuclide (TCN) geochronology, we dated 2 deformed fluvial terraces in the hanging wall of the Guaicaramo thrust fault. From the 10Be concentration and terrace profile relative to local base level, we calculated incision rates. We present a reconstructed slip history of the Guaicaramo thrust fault and its Quaternary slip rate. Furthermore, to quantify the regional Quaternary deformation, we look at the fluvial response to tectonic uplift. Approximately 20 streams along the eastern foothills of the Eastern Cordillera (EC) were studied using a digital elevation model (DEM). From the DEM, longitudinal profiles were created and normalized channel steepness (Ksn) values calculated from plots of drainage area vs. slope. Knickpoints in the longitudinal profiles can record transient perturbations or differential uplift. Calculated Ksn values indicate that the EC is experiencing high rates of uplift, with the highest mean Ksn values occurring in the Cocuy region. Mean channel steepness values along strike of the foothills are related to increasing uplift rates from south to north. In contrast, we suggest that high channel steepness values in the south appear to be controlled by high rates of annual precipitation.

  7. Assessment of corneal astigmatism following frown and straight incision forms in sutureless manual small incision cataract surgery

    Directory of Open Access Journals (Sweden)

    Amedo AO

    2016-04-01

    Full Text Available Angela Ofeibea Amedo, Kwadwo Amoah, Nana Yaa Koomson, David Ben Kumah, Eugene Appenteng Osae Department of Optometry and Visual Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana Abstract: To investigate which of two tunnel incision forms (frown versus straight in sutureless manual small incision cataract surgery creates more corneal astigmatism. Sixty eyes of 60 patients who had consented to undergo cataract surgery and to partake in this study were followed from baseline through >12-week postoperative period. Values of preoperative and postoperative corneal astigmatism for the 60 eyes, measured with a Bausch and Lomb keratometer, were extracted from the patients’ cataract surgery records. Residual astigmatism was computed as the difference between preoperative and postoperative keratometry readings. Visual acuity was assessed during the preoperative period and at each postoperative visit with a Snellen chart at 6 m. Fifty eyes of 50 patients were successfully followed-up on. Overall, the mean residual astigmatism was 0.75±0.12 diopters. The differences in mean residual astigmatism between the two different incision groups were statistically significant (t [48]=6.33, P<0.05; frown incision group recorded 1.00±0.12 diopters, whereas the straight incision group recorded 0.50±0.12 diopters. No significant difference was observed between male and female groups (t [48]=0.24, P>0.05. Residual corneal astigmatism in the frown incision group was significantly higher than in the straight incision group. Fisher’s exact test did not reveal a significant association between incision forms and visual acuity during the entire postoperative period (P>0.05. Keywords: cataract, residual corneal astigmatism, frown incision, straight incision

  8. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco

    2015-01-01

    Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter...

  9. Fluvial processes and channel morphometry of the upper Orashi ...

    African Journals Online (AJOL)

    Fluvial processes and channel morphometry of the upper Orashi basin in ... of channel equilibrium between morphology and hydrology, the Orashi channel is not well ... Drainage basins, watershed morphology, morphometric analysis, Nigeria ...

  10. Temporal correlation of fluvial and alluvial sequences in the Makran Range, SE-Iran

    Science.gov (United States)

    Kober, F.; Zeilinger, G.; Ivy-Ochs, S.; Dolati, A.; Smit, J.; Burg, J.-P.; Bahroudi, A.; Kubik, P. W.; Baur, H.; Wieler, R.; Haghipour, N.

    2009-04-01

    fluvial sequences to coastal terraces and wave-cut platforms is problematic due to ambiguous ages and obscured stratigraphic linkage. Our data suggest that events of terrace formation are roughly coeval between basins, but do not indicate a distinct climate forcing, though there is some tendency that terraces were formed during interglacial periods. Preliminary incision rates derived from strath terraces are on the order of 0.1-3 mm/yr with non-steady intervals. This in turn is well in the range of uplift rates deduced from coastal terraces. Further investigations are on the way, especially resolving complex exposure histories based on combining cosmogenic radionuclides and 21Ne.

  11. Cosmetic effects of skin-crease camouflage incision versus longitudinal incision following carotid endarterectomy.

    Science.gov (United States)

    Kazimierczak, Arkadiusz; Rybicka, Anita; Rynio, Pawel; Gutowski, Piotr; Wiernicki, Ireneusz

    2018-03-01

    Despite the increasing use of carotid angioplasty and stenting (CAS), carotid endarterectomy (CEA) nonetheless remains a more medically beneficial method of treatment for carotid artery stenosis. Therefore, one possibility for progress within this procedure may be to use minimally invasive carotid surgery, especially when the scar is in plain sight: the use of the natural wrinkles (skin crease) as a camouflage of the skin incision provides significant cosmetic improvements. To compare the cosmetic effects of classic and trans-wrinkle CEA. To assess the distance between the carotid artery bifurcation (CAB) and the skin-crease incision whilst attempting CEA. It was a randomized prospective study with two groups: patients undergoing classic surgery (control group; n = 100) and skin-crease trans-wrinkle camouflaged CEA (study group; n = 100). Follow-up was at 2 months and 1 year. The medical results of the treatment were similar in both groups. The cumulative count of strokes and myocardial infarctions was 0.5% within 30 days, and after one year 3.5% (and 5.5% including cases of death). The superiority of the transverse crease being hidden compared to the conventional longitudinal technique was proven in the Patient and Observer Scar Assessment Scale (POSAS) score, respectively 11.4 ±1.0 vs. 14.1 ±3.4 (p = 0.0001) after 2 months and 13.5 ±2.8 vs. 14.1 ±3.4 (p = 0.039) after a year. Trans-wrinkle incision gives better cosmetic results, can be safely performed in most cases, and offers a comfortable approach during CEA.

  12. High-power diode laser in the circumvestibular incision for Le Fort I osteotomy in orthognathic surgery: a prospective case series study.

    Science.gov (United States)

    Jaeger, Filipe; Chiavaioli, Gustavo Marques; de Toledo, Guilherme Lacerda; Freire-Maia, Belini; Amaral, Marcio Bruno Figueiredo; Mesquita, Ricardo Alves

    2018-01-01

    The incisions during orthognathic surgery are classically performed with conventional scalpel or electrocautery. Considering that the high-power diode laser surgery may provide advantages when compared to conventional incision techniques, the current study aimed to present a prospective case series of patients submitted to circumvestibular incision for Le Fort I osteotomy. Ten patients with dentofacial deformities who underwent to rapid assisted maxillary expansion or bimaxillary orthognathic surgery were enrolled in the study. All incisions were performed by a single surgeon using an 808-nm diode laser, with an optical fiber of 600 μm, at a power of 2.5 W, in a continuous-wave mode. The performance of the incision was evaluated by incision velocity, bleeding, edema, secondary infection, clinical healing, and pain. The velocity of the incision ranged from 0.10 to 0.20 mm/s (mean 0.13 ± 0.03 mm/s). Considering bleeding during the soft tissue incision, all surgeries were classified as absent bleeding. All patients presented a clinical healing of the surgical wound in a period that range from 3 to 5 weeks and experienced swelling during the follow-up period. On average, approximately 50% of the swelling had resolved after the third postoperative week, and 28.8% of swelling remained after 2 months after the surgery. The pain decreased after 2 and 3 days, and 90.0% of the patients reported no pain after 7 postoperative days. High-power diode laser is effective and safety during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgery decreasing bleeding, surgery time, pain, and edema after orthognathic surgery.

  13. A skin abscess model for teaching incision and drainage procedures.

    Science.gov (United States)

    Fitch, Michael T; Manthey, David E; McGinnis, Henderson D; Nicks, Bret A; Pariyadath, Manoj

    2008-07-03

    Skin and soft tissue infections are increasingly prevalent clinical problems, and it is important for health care practitioners to be well trained in how to treat skin abscesses. A realistic model of abscess incision and drainage will allow trainees to learn and practice this basic physician procedure. We developed a realistic model of skin abscess formation to demonstrate the technique of incision and drainage for educational purposes. The creation of this model is described in detail in this report. This model has been successfully used to develop and disseminate a multimedia video production for teaching this medical procedure. Clinical faculty and resident physicians find this model to be a realistic method for demonstrating abscess incision and drainage. This manuscript provides a detailed description of our model of abscess incision and drainage for medical education. Clinical educators can incorporate this model into skills labs or demonstrations for teaching this basic procedure.

  14. Large-scale coastal and fluvial models constrain the late Holocene evolution of the Ebro Delta

    Directory of Open Access Journals (Sweden)

    J. H. Nienhuis

    2017-09-01

    Full Text Available The distinctive plan-view shape of the Ebro Delta coast reveals a rich morphologic history. The degree to which the form and depositional history of the Ebro and other deltas represent autogenic (internal dynamics or allogenic (external forcing remains a prominent challenge for paleo-environmental reconstructions. Here we use simple coastal and fluvial morphodynamic models to quantify paleo-environmental changes affecting the Ebro Delta over the late Holocene. Our findings show that these models are able to broadly reproduce the Ebro Delta morphology, with simple fluvial and wave climate histories. Based on numerical model experiments and the preserved and modern shape of the Ebro Delta plain, we estimate that a phase of rapid shoreline progradation began approximately 2100 years BP, requiring approximately a doubling in coarse-grained fluvial sediment supply to the delta. River profile simulations suggest that an instantaneous and sustained increase in coarse-grained sediment supply to the delta requires a combined increase in both flood discharge and sediment supply from the drainage basin. The persistence of rapid delta progradation throughout the last 2100 years suggests an anthropogenic control on sediment supply and flood intensity. Using proxy records of the North Atlantic Oscillation, we do not find evidence that changes in wave climate aided this delta expansion. Our findings highlight how scenario-based investigations of deltaic systems using simple models can assist first-order quantitative paleo-environmental reconstructions, elucidating the effects of past human influence and climate change, and allowing a better understanding of the future of deltaic landforms.

  15. Morphodynamic Model of Submarine Canyon Incision by Sandblasting

    Science.gov (United States)

    Zhang, L.; Parker, G.; Izumi, N.; Cartigny, M.; Li, T.; Wang, G.

    2017-12-01

    Submarine canyons are carved by turbidity currents under the deep sea. As opposed to subaerial canyons, the relevant processes are not easy to observe directly. Turbidity currents are bottom-hugging sediment gravity flows of that can incise or deposit on the seafloor to create submarine canyons or fans. The triggers of turbidity currents can be storms, edge waves, internal waves, canyon wall sapping, delta failure, breaching and hyperpycnal flows. The formation and evolution mechanisms of submarine canyons are similar to those of subaerial canyons, but have substantial differences. For example, sandblasting, rather than wear due to colliding gravel clasts is more likely to be the mechanism of bedrock incision. Submarine canyons incise downward, and often develop meander bends and levees within the canyon, so defining "fairways". Here we propose a simple model for canyon incision. The starting point of our model is the Macro Roughness Saltation Abrasion Alluviation model of Zhang et al. [2015], designed for bedrock incision by gravel clasts in mixed bedrock-alluvial rivers. We adapt this formulation to consider sandblasting as a means of wear. We use a layer-averaged model for turbidity current dynamics. The current contains a mixture of mud, which helps drive the flow but which does not cause incision, and sand, which is the agent of incision. We show that the model can successfully model channel downcutting, and indeed illustrate the early formation of net incisional cyclic steps, i.e. upstream-migrating undulations on the bed associated with transcritical (in the Froude sense) flow. These steps can be expected to abet the process of incision.

  16. Diathermy versus scalpel incisions for open cholecystectomy comparative study

    International Nuclear Information System (INIS)

    Ali, M.A.; Niazi, W.A.K.

    2014-01-01

    The aim of the study was to make a comparison between skin incisions made with electrocautery versus scalpel in terms of their safety, efficacy and post-operative complications. Design: A randomized controlled study. Setting: The study was conducted in Combined Military Hospital (CMH) Kharian, Pakistan airforce (PAF) Hospital Sargodha. Duration of Study: May 2008 to August 2011. Patients and Methods: Ninety seven patients who underwent open cholecystectomy were randomly divided into two groups on the basis of the use of electrocautery versus steel scalpel for making skin incision and sub-cutaneous tissue dissection. Parameters recorded were, time taken from skin incision to full incising of the peritoneum, length of the wound, amount of blood loss during this step of surgery in each group. Post-operative pain scoring using visual analogue scale was done. Wound complications such as infection, haematoma/seroma and dehiscence were noted too. One month of follow up was recorded in each group. Subsequently a comparison of these findings was done. Results: Incision time (sec/cm/sub 2/) was longer in scalpel group than in diathermy group (p = 0.001), whereas, incision blood loss (ml/cm/sub 2/) was significantly less in diathermy group than in scalpel group (p = 0.03). There was no difference in post-operative pain perception as delineated by visual pain analogue scoring system between the two groups (p = 0.57). Post-operative wound complications and the final healing of wound at 01 month of follow-up were almost similar in both groups. Conclusion: Electrocautery may be used safely without any untoward complication in making skin incision and sub-cutaneous tissue dissection with an advantage of reduced incision time and and less blood loss. (author)

  17. Sedimentary architecture and chronostratigraphy of a late Quaternary incised-valley fill: A case study of the late Middle and Late Pleistocene Rhine system in the Netherlands

    Science.gov (United States)

    Peeters, J.; Busschers, F. S.; Stouthamer, E.; Bosch, J. H. A.; Van den Berg, M. W.; Wallinga, J.; Versendaal, A. J.; Bunnik, F. P. M.; Middelkoop, H.

    2016-01-01

    This paper describes the sedimentary architecture, chronostratigraphy and palaeogeography of the late Middle and Late Pleistocene (Marine Isotope Stage/MIS 6-2) incised Rhine-valley fill in the central Netherlands based on six geological transects, luminescence dating, biostratigraphical data and a 3D geological model. The incised-valley fill consists of a ca. 50 m thick and 10-20 km wide sand-dominated succession and includes a well-developed sequence dating from the Last Interglacial: known as the Eemian in northwest Europe. The lower part of the valley fill contains coarse-grained fluvio-glacial and fluvial Rhine sediments that were deposited under Late Saalian (MIS 6) cold-climatic periglacial conditions and during the transition into the warm Eemian interglacial (MIS 5e-d). This unit is overlain by fine-grained fresh-water flood-basin deposits, which are transgressed by a fine-grained estuarine unit that formed during marine high-stand. This ca. 10 m thick sequence reflects gradual drowning of the Eemian interglacial fluvial Rhine system and transformation into an estuary due to relative sea-level rise. The chronological data suggests a delay in timing of regional Eemian interglacial transgression and sea-level high-stand of several thousand years, when compared to eustatic sea-level. As a result of this glacio-isostatic controlled delay, formation of the interglacial lower deltaic system took only place for a relative short period of time: progradation was therefore limited. During the cooler Weichselian Early Glacial period (MIS 5d-a) deposition of deltaic sediments continued and extensive westward progradation of the Rhine system occurred. Major parts of the Eemian and Weichselian Early Glacial deposits were eroded and buried as a result of sea-level lowering and climate cooling during the early Middle Weichselian (MIS 4-3). Near complete sedimentary preservation occurred along the margins of the incised valley allowing the detailed reconstruction presented

  18. Marine intervals in Neogene fluvial deposits of western Amazonia

    Science.gov (United States)

    Boonstra, Melanie; Troelstra, Simon; Lammertsma, Emmy; Hoorn, Carina

    2014-05-01

    Amazonia is one of the most species rich areas on Earth, but this high diversity is not homogeneous over the entire region. Highest mammal and tree-alpha diversity is found in the fluvio-lacustrine Pebas system, a Neogene wetland associated with rapid radiation of species. The estuarine to marine origin of various modern Amazonian fish, plants, and invertebrates has been associated with past marine ingressions into this freshwater Pebas system. The exact nature and age of these invasions is, however, debated. Here we present new evidence from fluvial and fluvio-lacustrine deposits of Neogene age in southeast Colombia, that point to periods of widespread marine conditions in western Amazonia. Our evidence is based on an analysis of marine palynomorphs, such as organic linings of foraminifera and dinoflagellate cysts, present in dark sandy clay sediments that outcrop along the Caqueta and Amazon rivers. Characteristically, the foraminiferal linings can be assigned to three benthic morphotypes only, e.g. Ammonia, Elphidium and Trochammina. This low diversity assemblage is associated with estuarine/marginal marine conditions. No distinct marine elements such as shelf or planktonic species were encountered. The observed foraminiferal linings and dinocyst assemblages are typical for a (eutrophic) shallow marine environment, suggesting that the Pebas freshwater wetland system occasionally changed to (marginal) marine. Although some reworked elements are found, a typical Neogene dinocyst taxon is commonly found supporting in situ deposition. Sedimentological features typical for tidal conditions that are reported for sites in Peru and northeastern Brazil likely relate to these marine ingressions. Sea level changes as well as foreland basin development related to Andes formation may have facilitated the entry of marine water during the Neogene.

  19. Comparison of the Keratometric Corneal Astigmatic Power after Phacoemulsification: Clear Temporal Corneal Incision versus Superior Scleral Tunnel Incision

    Directory of Open Access Journals (Sweden)

    Yongqi He

    2009-01-01

    Full Text Available Objective. This is prospective randomized control trial to compare the mean keratometric corneal astigmatism diopter power (not surgical induced astigmatism among preop and one-month and three-month postop phacoemulcification of either a clear temporal corneal incision or a superior scleral tunnel Incision, using only keratometric astigmatic power reading to evaluate the difference between the two cataract surgery incisions. Methods. 120 patients (134 eyes underwent phacoemulcification were randomly assigned to two groups: Group A, the clear temporal corneal incision group, and Group B, the superior scleral tunnel incision group. SPSS11.5 Software was used for statistical analysis to compare the postsurgical changes of cornea astigmatism on keratometry. Results. The changes of corneal astigmatic diopter in Groups A and B after 3 month postop from keratometric reading were 1.04 + 0.76 and 0.94 + 0.27, respectively (=.84>.05, which showed no statistic significance difference. Conclusion. The incision through either temporal clear cornea or superior scleral tunnel in phacoemulcification shows no statistic difference in astigmatism change on keratometry 3-month postop.

  20. Fluvial to Lacustrine Facies Transitions in Gale Crater, Mars

    Science.gov (United States)

    Sumner, Dawn Y.; Williams, Rebecca M. E.; Schieber, Juergen; Palucis, Marisa C.; Oehler, Dorothy Z.; Mangold, Nicolas; Kah, Linda C.; Gupta, Sanjeev; Grotzinger, John P.; Grant, John A., III; hide

    2015-01-01

    NASA's Curiosity rover has documented predominantly fluvial sedimentary rocks along its path from the landing site to the toe of the Peace Vallis alluvial fan (0.5 km to the east) and then along its 8 km traverse across Aeolis Palus to the base of Aeolis Mons (Mount Sharp). Lacustrine facies have been identified at the toe of the Peace Vallis fan and in the lowermost geological unit exposed on Aeolis Mons. These two depositional systems provide end members for martian fluvial/alluvial-lacustrine facies models. The Peace Vallis system consisted of an 80 square kilometers alluvial fan with decimeter-thick, laterally continuous fluvial sandstones with few sedimentary structures. The thin lacustrine unit associated with the fan is interpreted as deposited in a small lake associated with fan runoff. In contrast, fluvial facies exposed over most of Curiosity's traverse to Aeolis Mons consist of sandstones with common dune-scale cross stratification (including trough cross stratification), interbedded conglomerates, and rare paleochannels. Along the southwest portion of the traverse, sandstone facies include south-dipping meter-scale clinoforms that are interbedded with finer-grained mudstone facies, interpreted as lacustrine. Sedimentary structures in these deposits are consistent with deltaic deposits. Deltaic deposition is also suggested by the scale of fluvial to lacustrine facies transitions, which occur over greater than 100 m laterally and greater than 10 m vertically. The large scale of the transitions and the predicted thickness of lacustrine deposits based on orbital mapping require deposition in a substantial river-lake system over an extended interval of time. Thus, the lowermost, and oldest, sedimentary rocks in Gale Crater suggest the presence of substantial fluvial flow into a long-lived lake. In contrast, the Peace Vallis alluvial fan onlaps these older deposits and overlies a major unconformity. It is one of the youngest deposits in the crater, and

  1. Fluvial-deltaic sedimentation and stratigraphy of the ferron sandstone

    Science.gov (United States)

    Anderson, P.B.; Chidsey, T.C.; Ryer, T.A.

    1997-01-01

    East-central Utah has world-class outcrops of dominantly fluvial-deltaic Turonian to Coniacian aged strata deposited in the Cretaceous foreland basin. The Ferron Sandstone Member of the Mancos Shale records the influences of both tidal and wave energy on fluvial-dominated deltas on the western margin of the Cretaceous western interior seaway. Revisions of the stratigraphy are proposed for the Ferron Sandstone. Facies representing a variety of environments of deposition are well exposed, including delta-front, strandline, marginal marine, and coastal-plain. Some of these facies are described in detail for use in petroleum reservoir characterization and include permeability structure.

  2. Rapid post-seismic landslide evacuation boosted by dynamic river width

    Science.gov (United States)

    Croissant, Thomas; Lague, Dimitri; Steer, Philippe; Davy, Philippe

    2017-09-01

    Mass wasting caused by large-magnitude earthquakes chokes mountain rivers with several cubic kilometres of sediment. The timescale and mechanisms by which rivers evacuate small to gigantic landslide deposits are poorly known, but are critical for predicting post-seismic geomorphic hazards, interpreting the signature of earthquakes in sedimentary archives and deciphering the coupling between erosion and tectonics. Here, we use a new 2D hydro-sedimentary evolution model to demonstrate that river self-organization into a narrower alluvial channel overlying the bedrock valley dramatically increases sediment transport capacity and reduces export time of gigantic landslides by orders of magnitude compared with existing theory. Predicted export times obey a universal non-linear relationship of landslide volume and pre-landslide valley transport capacity. Upscaling these results to realistic populations of landslides shows that removing half of the total coarse sediment volume introduced by large earthquakes in the fluvial network would typically take 5 to 25 years in various tectonically active mountain belts, with little impact of earthquake magnitude and climate. Dynamic alluvial channel narrowing is therefore a key, previously unrecognized mechanism by which mountain rivers rapidly digest extreme events and maintain their capacity to incise uplifted rocks.

  3. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

    Science.gov (United States)

    Gran, K. B.

    2015-12-01

    Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a

  4. Effects of two different incision phacoemulsification on corneal astigmatism

    Directory of Open Access Journals (Sweden)

    Lu Huo

    2014-12-01

    Full Text Available AIM:To compare the effect of different incision in corneal astigmatism after phacoemulsification. METHODS: Totally 88 cases(122 eyeswith pure cataract were randomly divided into two groups. Forty cases(60 eyeswere clarity corneal incision in group A, and 48 cases(62 eyeswere sclera tunnel incision in group B. Mean corneal astigmatism, surgically induced astigmatism(SIA, uncorrected visual acuity(UCVAand best correct vision acuity(BCVAwere observed in pre- and post-operation at 1d; 1wk; 1mo.RESULTS: The mean astigmatism had statistically significant difference between two groups at 1d; 1wk; 1mo after operation(PPP>0.05. UCVA≥0.5 and BCVA≥0.8 had statistically significant difference at 1d; 1wk(PP>0.05.CONCLUSION: Phacoemulsification with scleral tunnel incision remove combined intraocular lens(IOLimplantation has small changes to corneal astigmatism. By selecting personalized corneal incision according to the corneal topography might be more beneficial.

  5. Titan's fluvial valleys: Morphology, distribution, and spectral properties

    Science.gov (United States)

    Langhans, M.H.; Jaumann, R.; Stephan, K.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Baines, K.H.; Nicholson, P.D.; Lorenz, R.D.; Soderblom, L.A.; Soderblom, J.M.; Sotin, Christophe; Barnes, J.W.; Nelson, R.

    2012-01-01

    Titan's fluvial channels have been investigated based on data obtained by the Synthetic Aperture Radar (SAR) instrument and the Visible and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. In this paper, a database of fluvial features is created based on radar-SAR data aiming to unveil the distribution and the morphologic and spectral characteristics of valleys on Titan on a global scale. It will also study the spatial relations between fluvial valleys and Titan's geologic units and spectral surface units which have become accessible thanks to Cassini-VIMS data. Several distinct morphologic types of fluvial valleys can be discerned by SAR-images. Dendritic valley networks appear to have much in common with terrestrial dendritic systems owing to a hierarchical and tree-shaped arrangement of the tributaries which is indicative of an origin from precipitation. Dry valleys constitute another class of valleys resembling terrestrial wadis, an indication of episodic and strong flow events. Other valley types, such as putative canyons, cannot be correlated with rainfall based on their morphology alone, since it cannot be ruled out that they may have originated from volcanic/tectonic action or groundwater sapping. Highly developed and complex fluvial networks with channel lengths of up to 1200 km and widths of up to 10 km are concentrated only at a few locations whereas single valleys are scattered over all latitudes. Fluvial valleys are frequently found in mountainous areas. Some terrains, such as equatorial dune fields and undifferentiated plains at mid-latitudes, are almost entirely free of valleys. Spectrally, fluvial terrains are often characterized by a high reflectance in each of Titan's atmospheric windows, as most of them are located on Titan's bright 'continents'. Nevertheless, valleys are spatially associated with a surface unit appearing blue due to its higher reflection at 1.3??m in a VIMS false color RGB composite with R: 1.59/1.27??m, G: 2

  6. Modification of the Nuss Procedure: The Single-incision Technique

    Directory of Open Access Journals (Sweden)

    Tetsushi Aizawa, MD

    2014-11-01

    Full Text Available Summary: The Nuss procedure is a prevalent minimally invasive surgery for pectus excavatum. Although the Nuss procedure has the advantage of leaving less obtrusive scars, the standard technique requires at least 3 skin incisions to insert several instruments. We experienced 7 cases of the modified Nuss procedure using a single incision during a 7-year period. To facilitate passing of the bar, a traction guide was created according to our unique method. There was no need for a bar stabilizer, and no severe intraoperative complications occurred. All patients exhibited satisfactory short-term results; however, 1 patient suffered from bar rotation and required repeat surgery for fixation. Two patients underwent bar removal via the same single incision without any difficulties.

  7. Minimizing surgical skin incision scars with a latex surgical glove.

    Science.gov (United States)

    Han, So-Eun; Ryoo, Suk-Tae; Lim, So Young; Pyon, Jai-Kyung; Bang, Sa-Ik; Oh, Kap-Sung; Mun, Goo-Hyun

    2013-04-01

    The current trend in minimally invasive surgery is to make a small surgical incision. However, the excessive tensile stress applied by the retractors to the skin surrounding the incision often results in a long wound healing time and extensive scarring. To minimize these types of wound problems, the authors evaluated a simple and cost-effective method to minimize surgical incision scars based on the use of a latex surgical glove. The tunnel-shaped part of a powder-free latex surgical glove was applied to the incision and the dissection plane. It was fixed to the full layer of the dissection plane with sutures. The glove on the skin surface then was sealed with Ioban (3 M Health Care, St. Paul, MN, USA) to prevent movement. The operation proceeded as usual, with the retractor running through the tunnel of the latex glove. It was possible to complete the operation without any disturbance of the visual field by the surgical glove, and the glove was neither torn nor separated by the retractors. The retractors caused traction and friction during the operation, but the extent of damage to the postoperative skin incision margin was remarkably less than when the operation was performed without a glove. This simple and cost-effective method is based on the use of a latex surgical glove to protect the surgical skin incision site and improve the appearance of the postoperative scar. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  8. A Pleistocene coastal alluvial fan complex produced by Middle Pleistocene glacio-fluvial processes

    Science.gov (United States)

    Adamson, Kathryn; Woodward, Jamie; Hughes, Philip; Giglio, Federico; Del Bianco, Fabrizio

    2014-05-01

    contains deeply incised (up to 10 m) channels which are similar in morphology to those exposed onshore. It is likely that strong cementation of the fan sediments, and associated channel forms, has protected them from coastal erosion during several regression-transgression cycles. These records provide important opportunities to correlate the Pleistocene terrestrial glacial and fluvial records with the marine archive.

  9. Field migration rates of tidal meanders recapitulate fluvial morphodynamics

    Science.gov (United States)

    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-01

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths.

  10. Fluvial hydrology and geomorphology of Monsoon-dominated Indian rivers

    Directory of Open Access Journals (Sweden)

    Vishwas S. Kale

    2005-11-01

    Full Text Available The Indian rivers are dominantly monsoon rainfed. As a result, their regime characteristics are dictated by the spatio-temporal variations in the monsoon rainfall. Although the rivers carry out most of the geomorphic work during 4-5 months of the monsoon season, the nature and magnitude of response to variations in the discharge and sediment load varies with the basin size and relief characteristics. Large monsoon floods play a role of great importance on all the rivers. This paper describes the hydrological and geomorphological characteristics of the two major fluvial systems of the Indian region, namely the Himalayan fluvial system and the Peninsular fluvial system. Large number of studies published so far indicate that there are noteworthy differences between the two river systems, with respect to river hydrology, channel morphology, sediment load and behaviour. The nature of alterations in the fluvial system due to increased human interference is also briefly mentioned. This short review demonstrates that there is immense variety of rivers in India. This makes India one of the best places to study rivers and their forms and processes.

  11. Field migration rates of tidal meanders recapitulate fluvial morphodynamics.

    Science.gov (United States)

    Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

    2018-02-13

    The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths. Copyright © 2018 the Author(s). Published by PNAS.

  12. Influence of fluvial sandstone architecture on geothermal energy production

    NARCIS (Netherlands)

    Willems, C.J.L.; Maghami Nick, Hamidreza M.; Weltje, G.J.; Donselaar, M.E.; Bruhn, D.F.

    2015-01-01

    Fluvial sandstone reservoirs composed of stacked meander belts are considered as potential geothermal resources in the Netherlands. Net-to-gross, orientation and stacking pattern of the channel belts is of major importance for the connectivity between the injection and production well in such

  13. Does deposition depth control the OSL bleaching of fluvial sediment?

    NARCIS (Netherlands)

    Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

    2014-01-01

    The Optically Stimulated Luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  14. A model of plant strategies in fluvial hydrosystems

    NARCIS (Netherlands)

    Bornette, G.; Tabacchi, E.; Hupp, C.; Puijalon, S.; Rostan, J.C.

    2008-01-01

    1. We propose a model of plant strategies in temperate fluvial hydrosystems that considers the hydraulic and geomorphic features that control plant recruitment, establishment and growth in river floodplains. 2. The model describes first how the disturbance gradient and the grain-size of the river

  15. Heavy mineral analyses as a powerful tool in fluvial geomorphology

    Science.gov (United States)

    von Suchodoletz, Hans; Gärtner, Andreas; Faust, Dominik

    2014-05-01

    The Marneuli depression is a tectonic sub-basin of the Transcaucasian depression in eastern Georgia, filled with several decametres of fluvial, lacustrine and aeolian Quaternary sediments. In order to reconstruct past landscape evolution of the region we studied Late Quaternary fluvial sediments found along several rivers that flow through that depression. Whereas Holocene river sediments could generally easily be assigned to corresponding rivers, this was not always the case for older fluvial sediments. For this reason, we studied the heavy mineral contents of five recent rivers and of four sedimentary deposits of potential precursors. A total of 4088 analysed heavy mineral grains enabled us to set up the characteristic heavy mineral distribution pattern for each sample. Using these data, we were able to reconstruct the most likely source areas of the Late Pleistocene fluvial sediments and to link them with the catchment areas of recent rivers. This allowed us to identify and to substantiate significant Late Quaternary river diversions that could at least partly be assigned to ongoing tectonic processes.

  16. Better outcome from arthroscopic partial meniscectomy than skin incisions only?

    DEFF Research Database (Denmark)

    Roos, Ewa M; Hare, Kristoffer Borbjerg; Nielsen, Sabrina Mai

    2018-01-01

    . In total, nine participants experienced 11 adverse events; six in the surgery group and three in the skin-incisions-only group. CONCLUSION: We found greater improvement from arthroscopic partial meniscectomy compared with skin incisions only at 2 years, with the statistical uncertainty of the between......-group difference including what could be considered clinically relevant. Because of the study being underpowered, nearly half in the sham group being non-blinded and one-third crossing over to surgery, the results cannot be generalised to the greater patient population. TRIAL REGISTRATION NUMBER: NCT01264991....

  17. Rapid Gorge Formation in an Artificially Created Waterfall

    Science.gov (United States)

    Anton, L.; Mather, A. E.; Stokes, M.; Munoz Martin, A.

    2014-12-01

    A number of studies have examined rates of gorge formation, nick point retreat, and the controls on those rates via bedrock erodibility, the effectiveness of bedrock erosion mechanisms and the role of hillslope processes. Most findings are based on conceptual / empirical models or long term landscape analysis; but studies of recent quantifiable events are scarce yet highly valuable. Here we present expert eye witness account and quantitative survey of large and rapid fluvial erosion events that occurred over an artificially created waterfall at a spillway mouth. In 6 years a ~270 m long, ~100 m deep and ~100 to 160 m wide canyon was carved, and ~1.58 x106 m3 of granite bedrock was removed from the spillway site. Available flow data indicates that the erosion took place under unremarkable flood discharge conditions. The analysis of historic topographic maps enables the reconstruction of the former topography and successive erosion events, enabling the quantification of bedrock erosion amounts, and rates. Analysis of bedrock erodibility and discontinuity patterns demonstrates that the bedrock is mechanically strong, and that similar rock strength and fracture patterns are found throughout the region. It is apparent that structural pre-conditioning through fracture density and orientation in relation to flow and slope direction is of paramount importance in the gorge development. The presented example provides an exceptional opportunity for studying the evolution process of a bedrock canyon and to precisely measure the rate of bedrock channel erosion over a six year period. Results illustrate the highly episodic nature of the erosion and highlight several key observations for the adjustability of bedrock rivers. The observations have implications for the efficiency of bedrock erosion and raise important questions about incision rates, driving mechanisms and timescale assumptions' in models of landscape change.

  18. Beaver ponds' impact on fluvial processes (Beskid Niski Mts., SE Poland).

    Science.gov (United States)

    Giriat, Dorota; Gorczyca, Elżbieta; Sobucki, Mateusz

    2016-02-15

    Beaver (Castor sp.) can change the riverine environment through dam-building and other activities. The European beaver (Castor fiber) was extirpated in Poland by the nineteenth century, but populations are again present as a result of reintroductions that began in 1974. The goal of this paper is to assess the impact of beaver activity on montane fluvial system development by identifying and analysing changes in channel and valley morphology following expansion of beaver into a 7.5 km-long headwater reach of the upper Wisłoka River in southeast Poland. We document the distribution of beaver in the reach, the change in river profile, sedimentation type and storage in beaver ponds, and assess how beaver dams and ponds have altered channel and valley bottom morphology. The upper Wisłoka River fluvial system underwent a series of anthropogenic disturbances during the last few centuries. The rapid spread of C. fiber in the upper Wisłoka River valley was promoted by the valley's morphology, including a low-gradient channel and silty-sand deposits in the valley bottom. At the time of our survey (2011), beaver ponds occupied 17% of the length of the study reach channel. Two types of beaver dams were noted: in-channel dams and valley-wide dams. The primary effect of dams, investigated in an intensively studied 300-m long subreach (Radocyna Pond), was a change in the longitudinal profile from smooth to stepped, a local reduction of the water surface slope, and an increase in the variability of both the thalweg profile and surface water depths. We estimate the current rate of sedimentation in beaver ponds to be about 14 cm per year. A three-stage scheme of fluvial processes in the longitudinal and transverse profile of the river channel is proposed. C. fiber reintroduction may be considered as another important stage of the upper Wisłoka fluvial system development. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Sediment dynamics in the Rhine catchment : Quantification of fluvial response to climate change and human impact

    NARCIS (Netherlands)

    Erkens, G.

    2009-01-01

    Fluvial systems are strongly responsive to changes in climate and land use — but take their time to show it. Accurate prediction of the timing and degree of future fluvial response requires comprehensive understanding of fluvial response in the past. This PhD-thesis studied the response of the river

  20. Meta-analysis of the effectiveness of surgical scalpel or diathermy in making abdominal skin incisions.

    LENUS (Irish Health Repository)

    Ahmad, Nasir Zaheer

    2012-02-01

    BACKGROUND: Surgical scalpels are traditionally used to make skin incisions. Diathermy incisions on contrary are less popular among the surgeons. The aim of this meta-analysis was to compare the effectiveness of both techniques and address the common fallacies about diathermy incisions. METHODS: A literature search of MEDLINE and Cochrane databases was done, using the keywords diathermy, cold scalpel, and incisions. Eleven clinical trials comparing both methods of making skin incisions were selected for meta-analysis. The end points compared included postoperative wound infection, pain in first 24 hours after surgery, time taken to complete the incisions, and incision-related blood loss. RESULTS: Postoperative wound infection rate was comparable in both techniques (P = 0.147, odds ratio = 1.257 and 95% CI = 0.923-1.711). Postoperative pain was significantly less with diathermy incisions in first 24 hours (P = 0.031, weighted mean difference = 0.852 and 95% CI = 0.076-1.628). Similarly, the time taken to complete the incision and incision-related blood loss was significantly less with diathermy incisions (95% CI = 0.245-0.502 and 0.548-1.020, respectively). CONCLUSION: Diathermy incisions are equally prone to get wound infection, as do the incisions made with scalpel. Furthermore, lower incidence of early postoperative pain, swiftness of the technique, and a reduced blood loss are the encouraging facts supporting routine use of diathermy for abdominal skin incisions after taking careful precautions.

  1. Fluvial signatures of modern and paleo orographic rainfall gradients

    Science.gov (United States)

    Schildgen, Taylor; Strecker, Manfred

    2016-04-01

    arid precipitation regimes. Indeed, despite uniform lithology and uplift history, we see patterns in river steepness values and in chi plots that are consistest a rainfall gradient on the (former) windward side of the range and asymmetric precipitation across the range. We suggest that morphological aspects of the river networks in such regions are dominated by their history of changing climate. These morphologic signatures appear to persist for millions of years in NW Argentina, most likely because the transition from a wetter to a drier climate has prevented a rapid readjustment to new forcing conditions. Reference: Han, J., Gasparini, N.M., and Johnson, J.P., 2015, Measuring the imprint of orographic rainfall gradients on the morphology of steady-state numerical fluvial landscapes. Earth Surf. Process. Landforms, 40(10), 1334-1350.

  2. Evaluating process origins of sand-dominated fluvial stratigraphy

    Science.gov (United States)

    Chamberlin, E.; Hajek, E. A.

    2015-12-01

    Sand-dominated fluvial stratigraphy is often interpreted as indicating times of relatively slow subsidence because of the assumption that fine sediment (silt and clay) is reworked or bypassed during periods of low accommodation. However, sand-dominated successions may instead represent proximal, coarse-grained reaches of paleo-river basins and/or fluvial systems with a sandy sediment supply. Differentiating between these cases is critical for accurately interpreting mass-extraction profiles, basin-subsidence rates, and paleo-river avulsion and migration behavior from ancient fluvial deposits. We explore the degree to which sand-rich accumulations reflect supply-driven progradation or accommodation-limited reworking, by re-evaluating the Castlegate Sandstone (Utah, USA) and the upper Williams Fork Formation (Colorado, USA) - two Upper Cretaceous sandy fluvial deposits previously interpreted as having formed during periods of relatively low accommodation. Both units comprise amalgamated channel and bar deposits with minor intra-channel and overbank mudstones. To constrain relative reworking, we quantify the preservation of bar deposits in each unit using detailed facies and channel-deposit mapping, and compare bar-deposit preservation to expected preservation statistics generated with object-based models spanning a range of boundary conditions. To estimate the grain-size distribution of paleo-sediment input, we leverage results of experimental work that shows both bed-material deposits and accumulations on the downstream side of bars ("interbar fines") sample suspended and wash loads of active flows. We measure grain-size distributions of bar deposits and interbar fines to reconstruct the relative sandiness of paleo-sediment supplies for both systems. By using these novel approaches to test whether sand-rich fluvial deposits reflect river systems with accommodation-limited reworking and/or particularly sand-rich sediment loads, we can gain insight into large

  3. How to find the sedimentary archive of fluvial pollution in a bedrock-confined river reach

    Science.gov (United States)

    Elznicova, Jitka; Matys Grygar, Tomas; Kiss, Timea; Lelkova, Tereza; Balogh, Marton; Sikora, Martin

    2016-04-01

    The Ohre River springs in the Eastern Germany and it is a tributary of the Labe (Elbe) River in Northwest Bohemia. The river received pollution from several sources during the last five centuries. Most of the pollution sources located along the upper and middle reaches, where the depositional and erosional pattern of the river is highly variable. The upper part of the catchment consists of mainly felsic rocks and the river has a broad floodplain. The middle reach and its right-bank tributaries are deeply incised into the Doupovske Hory Mts., which consists of mafic volcanic rocks; whereas the left-bank tributaries are incised into intrusive and metamorphic rocks of the Krusne Hory Mts. (Ore mountains) with several local ore mines (Ag, Pb and U) in particular in around Olovi and Jachymov. Due to the geologic and geomorphologic complexity, deposition of historical sediments in the middle reach has been spatially limited and uneven, and anomalous background concentrations of risk elements are expected. As a consequence, in the middle reach of the Ohre River it is difficult to find a useful sedimentary archive of historical pollution, though it is desired for two main reasons: (1) to decipher the undocumented and poorly described pollution history from the Krusne Hory Mts. and (2) to better understand the retention of pollutants in the transport zones of a confined river system. Based on historical maps we identified a side-bar (35x320 m) in the middle reach of the river near Straz on Ohre and aimed to describe its formation, its recent erosion/deposition history and to evaluate its sedimentary archive value. In the first half of the 19th century it was an island separated from the valley edge by a side channel. Since then there has been no apparent lateral accretion of the bar (its shape has not been changed), but the upstream part of the side channel aggraded by a sediment plug. We evaluated the current bar topography and geomorphology by a detailed field survey

  4. The origin and significance of sinuosity along incising bedrock rivers

    Science.gov (United States)

    Barbour, Jonathan Ross

    Landscapes evolve through processes acting at the earth's surface in response to tectonics and climate. Rivers that cut into bedrock are particularly important since they set the local baselevel and communicate changes in boundary conditions across the landscape through erosion and deposition; the pace of topographic evolution depends on both the rate of change of the boundary conditions and the speed of the bedrock channel network response. Much of the work so far has considered the effects of tectonically-controlled changes in slope and climatically-controlled changes in discharges to the rate of channel bed erosion while considering bank erosion, if active at all, to be of at best secondary importance to landscape evolution. Sprinkled throughout the literature of the past century are studies that have recognized lateral activity along incising rivers, but conflicting interpretations have left many unanswered questions about how to identify and measure horizontal erosion, what drives it, what effect it has on the landscape, and how it responds to climate and tectonics. In this thesis, I begin to answer some of these questions by focusing on bedrock river sinuosity and its evolution through horizontal erosion of the channel banks. An analysis of synoptic scale topography and climatology of the islands of eastern Asia reveals a quantitative signature of storm frequency in a regional measure of mountain river sinuosity. This is partly explained through a study of the hydro- and morphodynamics of a rapidly evolving bedrock river in Taiwan which shows how the erosive forces vary along a river to influence the spatiotemporal distribution of downcutting, sidecutting, and sediment transport. Through these analyses, I also present evidence that suggests that the relative frequency of erosive events is far more important than the absolute magnitude of extreme events in setting the erosion rate, and I show that the horizontal erosion of bedrock rivers is an important

  5. Minimal incision surgery in strabismus: Modified fornix-based approach.

    Science.gov (United States)

    Pérez-Flores, I

    2016-07-01

    To evaluate the modified fornix-based technique as an approach for minimal incision surgery in strabismus. The medical records of all consecutive patients that underwent strabismus surgery with fornix-based conjunctival incision between 2007 and 2012 were retrospectively reviewed. As a primary variable, an analysis was made of the wound size depending on the number of stitches. A descriptive study was performed on the variables related to patients and to the type of strabismus and surgery. Out of 153patients identified, 138 with 294 surgeries were included. In 200 (68%) interventions, the incision was sutured with one stitch, in 77 (26.2%) with 2, in 13 (4.4%) with 3, and in 4 (1.4%) with 4, with the mean number of stitches being 1.39±0.64. The mean age of the patients was 39years (2-80), and 36 (26.1%) had previous strabismus surgery, with topical anaesthesia being used in 35 (25.4%) cases. At 3months after surgery deviation was ≤10DP in 114 (82.6%) patients. There were no wound-related complications. The modified fornix-based technique is an effective and safe approach for minimal incision surgery in strabismus, in patients at all ages, with previous history of strabismus surgery and with topical anaesthesia. Copyright © 2015 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  6. Phenomenon of mucous retention in the incisive canal.

    Science.gov (United States)

    Keith, D A

    1979-11-01

    Mucous glands are rarely found in the anterior palate but may be observed in the incisive canal. A case history is presented of a lesion that resembled a nasopalatine cyst both clinically and radiographically but which was in fact an intra-bony extravasation phenomenon.

  7. Heterotopic ossification in abdominal incision : a case report

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Yoon Sik; Nam, Kung Sook; Hwang, Im Kyung; Kim, Heung Chul [College of Medicine, Hallym Univ., Chuncheon (Korea, Republic of)

    2001-08-01

    Heterotopic ossification in abdominal incision is a rare post-surgical sequala and a subtype of myositis ossificans traumatica. Recognition of this rare condition is important because it may be misinterpreted as a retained foreign body or incisional neoplastic recurrence. We report a case involving a 59-year-old man who presented with a palpable epigastric mass and pronounced fatigability.

  8. Tubularized incised plate technique for recurrent hypospadias: a ...

    African Journals Online (AJOL)

    management of recurrent hypospadias. Summary background ... The potential advantages of tubularized incised plate .... after a mean duration of 4.9 ± 3.1 years from the previous repair (Table 2). .... erection and the risk of infection, especially in patients older than 15 .... However, previous surgery often limits the availability ...

  9. Ultrasonic diagnosis and transurethral incision of ureterocele with hydronephrosis

    DEFF Research Database (Denmark)

    Waaddegaard, P; Miskowiak, J; Stage, P

    1991-01-01

    In a 65-year-old woman with right-sided loin pain, ultrasonography revealed a grossly dilated and obstructed right pyelogram due to a 50-mm ureterocele. After transurethral lateral incision of the ureterocele, there was complete recovery without vesicoureteric reflux. Ultrasonography is advantage...

  10. Single-incision laparoscopic cholecystectomy with needle graspers.

    Science.gov (United States)

    Sumiyoshi, Kinjiro; Sato, Norihiro; Akagawa, Shin; Hirano, Tatsuya; Koikawa, Kazuhiro; Horioka, Kohei; Ozono, Keigo; Fujiwara, Kenji; Tanaka, Masao; Sada, Masayuki

    2012-01-01

    Single-incision laparoscopic cholecystectomy (SILC) is a promising alternative to standard multi-incision laparoscopic cholecystectomy (LC). However, generalization of SILC is still hampered by technical difficulties mainly associated with the lack of trocars used for retraction of the gallbladder. We therefore developed a modified method of SILC with the use of needle graspers (SILC-N) for optimal retraction and exposure. In addition to two trocars inserted through a single transumbilical incision, two needle ports were placed on the right subcostal and lateral abdominal wall, through which needle graspers were used for retraction of the gallbladder. Since December, 2009, 12 patients with symptomatic cholelithiasis were treated by SILC-N. SILC-N was successfully performed in all but one patient requiring a conversion to the 4-port LC with a mean operative time of 71.5 (48-107) minutes. None of the patients experienced intraoperative or postoperative complications. The transumbilical incision and pinholes for needle graspers were almost invisible on discharge. Our preliminary results suggest that SILC-N is a simple, safe and feasible technique of cholecystectomy offering similar postoperative recovery and better cosmetic outcome as compared to conventional LC.

  11. Single-incision laparoscopic surgery for pyloric stenosis.

    Science.gov (United States)

    Kozlov, Yury; Novogilov, Vladimir; Podkamenev, Alexey; Rasputin, Andrey; Weber, Irina; Solovjev, Alexey; Yurkov, Pavel

    2012-04-01

    Laparoscopy is the most common procedure for correction of congenital pyloric stenosis. The standard laparoscopic approach is based on the three-port technique. In contrast to the standard laparoscopic technique, the single-incision laparoscopic surgery (SILS) requires only one incision. We report on our experience with this surgical approach. Between September 2009 and August 2010 a total of 24 children underwent a laparoscopic pyloromyotomy, 12 in SILS technique. The single incision was carried through the center of the umbilicus. The working instruments were introduced in a two-dimensional direction into the peritoneal cavity via the same umbilical incision. The two groups were compared for patients' demographics, operative report and early postoperative outcomes. All SILS procedures were performed successfully with no conversion rate. There were no differences in the preoperative parameters between the two groups regarding age before surgery and body weight at operation. Operative time and time of full enteral intake was similar to comparable procedures with usage of a standard laparoscopic approach. There were no operative or postoperative complications. The early experience described in this study confirms that SILS can be applied for treatment of pyloric stenosis with outcomes similar to the standard laparoscopic surgery.

  12. Cost assessment of instruments for single-incision laparoscopic cholecystectomy

    DEFF Research Database (Denmark)

    Henriksen, Nadia A; Al-Tayar, Haytham; Rosenberg, Jacob

    2012-01-01

    Specially designed surgical instruments have been developed for single-incision laparoscopic surgery, but high instrument costs may impede the implementation of these procedures. The aim of this study was to compare the cost of operative implements used for elective cholecystectomy performed...

  13. Geomorphic controls on fluvial carbon exports and emissions from upland swamps in eastern Australia.

    Science.gov (United States)

    Cowley, Kirsten; Looman, Arun; Maher, Damien T; Fryirs, Kirstie

    2018-03-15

    Temperate Highland Peat Swamps on Sandstone (THPSS) are upland wetlands, similar to fens in the Northern Hemisphere and are found at the headwaters of low-order streams on the plateaus of Eastern Australia. They are classified as endangered ecological communities under State and National legislation. Previous works have identified particular geomorphic characteristics that are important to carbon storage in these low energy sediment accumulation zones. Changes in the geomorphic structure of THPSS, such as channelisation, may have profound implications for carbon storage. To assess the effect of channelisation on carbon budgets in these ecosystems it is essential to identify and quantify differences in carbon export, emissions and stocks of carbon of intact swamps and those that have become channelised. We undertook seasonal sampling of the perched swamp aquifers and surface waters of two intact swamps and two channelised fills in the Blue Mountains of New South Wales, Australia, to investigate differences in carbon exports and emissions between the two swamp types. We found that channelised fills' mean CO 2 emissions were almost four times higher than intact swamps with mean CH 4 emissions up to five times higher. Annual fluvial carbon exports for channelised fills were up to 18 times that of intact swamps. Channelised fill exports and emissions can represent up to 2% of the total swamp carbon stocks per annum which is 40 times higher than the intact swamps. This work clearly demonstrates that changes in geomorphic structure brought about by incision and channelisation results in profound changes to the carbon storage function of THPSS. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. [External periareolar incision for subdermal mastectomy in men with gynecomastia].

    Science.gov (United States)

    Montiel-Jarquín, Alvaro; Reyes-Páramo, Pedro; Ramos-Alvarez, Gloria; López-Colombo, Aurelio; Tinajero-Esquivel, Magdalena; Ruiz-León, Betzabé

    2007-01-01

    Gynecomastia describes a benign increase of the mammary gland in men. When medical treatment fails, symptoms and psychological alterations persist. Subdermal mastectomy is the definitive treatment and can be achieved by different incisions, each with potential complications. We undertook this study to present clinical characteristics of 11 patients with gynecomastia and the results obtained with subdermal mastectomy by means of external periareolar incision. A descriptive cohort study in male patients with gynecomastia was carried out in a third-level medical care hospital. Patients were treated with subdermal mastectomy by means of external periareolar incision. There were 11 male patients with an average age of 19 years (range: 11-60 years), 3 patients (27.2%) with bilateral gynecomastia and 8 patients (72.7%) with unilateral gynecomastia. Average time of evolution was 22 months (range: 16-48 months), 9 patients (81.8%) reported pain, 11 patients (100%) reported psychological alterations with cutaneous alteration, 11 patients (100%) had normal secondary sexual characteristics, 1 patient (9%) had supernumerary nipple development, and 11 patients (100%) had well-defined lesions. According to Simon's classification: seven patients (63.6%) were classified as grade 1, three patients (27.2%) as grade 2 and one patient (9.09%) as grade 3. Each patient had a subdermal mastectomy with external periareolar incision, 11 patients (100%) had a histopathological report of gynecomastia; 1 patient (9.09%) displayed keloid healing and none displayed complications inherent to the surgical procedure. Mastectomy by means of external periareolar incision is useful in the treatment of gynecomastia.

  15. Experimental investigation of fluvial dike breaching due to flow overtopping

    Science.gov (United States)

    El Kadi Abderrezzak, K.; Rifai, I.; Erpicum, S.; Archambeau, P.; Violeau, D.; Pirotton, M.; Dewals, B.

    2017-12-01

    The failure of fluvial dikes (levees) often leads to devastating floods that cause loss of life and damages to public infrastructure. Overtopping flows have been recognized as one of the most frequent cause of dike erosion and breaching. Fluvial dike breaching is different from frontal dike (embankments) breaching, because of specific geometry and boundary conditions. The current knowledge on the physical processes underpinning fluvial dike failure due to overtopping remains limited. In addition, there is a lack of a continuous monitoring of the 3D breach formation, limiting the analysis of the key mechanisms governing the breach development and the validation of conceptual or physically-based models. Laboratory tests on breach growth in homogeneous, non-cohesive sandy fluvial dikes due to flow overtopping have been performed. Two experimental setups have been constructed, permitting the investigation of various hydraulic and geometric parameters. Each experimental setup includes a main channel, separated from a floodplain by a dike. A rectangular initial notch is cut in the crest to initiate dike breaching. The breach development is monitored continuously using a specific developed laser profilometry technique. The observations have shown that the breach develops in two stages: first the breach deepens and widens with the breach centerline being gradually shifted toward the downstream side of the main channel. This behavior underlines the influence of the flow momentum component parallel to the dike crest. Second, the dike geometry upstream of the breach stops evolving and the breach widening continues only toward the downstream side of the main channel. The breach evolution has been found strongly affected by the flow conditions (i.e. inflow discharge in the main channel, downstream boundary condition) and floodplain confinement. The findings of this work shed light on key mechanisms of fluvial dike breaching, which differ substantially from those of dam

  16. A History of Pebbles and Silt – Fluvial Sediment Transport, Hydropower and Technical Expertise at the Austrian Danube and its Tributaries

    Directory of Open Access Journals (Sweden)

    Schoder Angelika

    2016-08-01

    Full Text Available The paper investigates experts’ perceptions of hydropower, sediment regime, and their interaction in the 20th century with an environmental historical approach, based on various case studies at both the Danube River and one of its tributaries, and on a review of contemporary literature authored by engineers. Results show that questions of sediment continuity have engaged planners of hydropower plants since the advent of this technology, and decisions were at any time influenced by multiple interests (navigation, electricity demand, nature conservation. In such an intricate fluvial landscape, phenomena like reservoir sedimentation and riverbed incision can be approached as “legacies” of past technical interventions, which limit the options of current and future river management.

  17. The width of the incisive canal and labial alveolar bone of the incisive canal: an assessment on CT images

    International Nuclear Information System (INIS)

    Roh, Yang Gyun; Jang, Hyun Seon; Kim, Byung Ock; Kim, Jin Soo

    2006-01-01

    To assess the width of the labial alveolar bone of the incisive canal and the width of the incisive canal on spiral computed tomographic images of the anterior portion of the maxilla. Study materials included 38 CT scans taken for preoperative planning of implant placement. Axial cross-sectioned image entirely showing the incisive canal at an orifice to the oral cavity, middle portion, and an orifice to the nasal cavity and the diameter of the incisive canal at the middle portion were determined by two specialist using Digora for Windows 2.1. The statistical analyses were carried out using SPSS 12.0.1. When the maxillary central incisors remained, the mean labial alveolar bone width were 6.81±1.41 mm, 6.46±1.33 mm, and 7.91±1.33 mm. When the maxillary central incisors were missed the mean width were 5.42±2.20 mm, 6.23±2.29 mm, and 7.89±2.13 mm. The labial alveolar bone width at middle portion and an orifice to the nasal cavity were of no statistical significant difference according to presence of the maxillary central incisors (P>0.05). The width between oral cavity and nasal cavity, middle portion and to masal cavity revealed statistically significant difference (P<0.05)

  18. Incisional hernia after upper abdominal surgery: A randomised controlled trial of midline versus transverse incision

    NARCIS (Netherlands)

    J.A. Halm (Jens); H. Lip (Harm); P.I.M. Schmitz (Paul); J. Jeekel (Hans)

    2009-01-01

    textabstractObjectives: To determine whether a transverse incision is an alternative to a midline incision in terms of incisional hernia incidence, surgical site infection, postoperative pain, hospital stay and cosmetics in cholecystectomy. Summary background data: Incisional hernias after midline

  19. A geologic approach to field methods in fluvial geomorphology

    Science.gov (United States)

    Fitzpatrick, Faith A.; Thornbush, Mary J; Allen, Casey D; Fitzpatrick, Faith A.

    2014-01-01

    A geologic approach to field methods in fluvial geomorphology is useful for understanding causes and consequences of past, present, and possible future perturbations in river behavior and floodplain dynamics. Field methods include characterizing river planform and morphology changes and floodplain sedimentary sequences over long periods of time along a longitudinal river continuum. Techniques include topographic and bathymetric surveying of fluvial landforms in valley bottoms and describing floodplain sedimentary sequences through coring, trenching, and examining pits and exposures. Historical sediment budgets that include floodplain sedimentary records can characterize past and present sources and sinks of sediment along a longitudinal river continuum. Describing paleochannels and floodplain vertical accretion deposits, estimating long-term sedimentation rates, and constructing historical sediment budgets can assist in management of aquatic resources, habitat, sedimentation, and flooding issues.

  20. Surficial geological tools in fluvial geomorphology: Chapter 2

    Science.gov (United States)

    Jacobson, Robert B.; O'Connor, James E.; Oguchi, Takashi

    2016-01-01

    Increasingly, environmental scientists are being asked to develop an understanding of how rivers and streams have been altered by environmental stresses, whether rivers are subject to physical or chemical hazards, how they can be restored, and how they will respond to future environmental change. These questions present substantive challenges to the discipline of fluvial geomorphology, especially since decades of geomorphologic research have demonstrated the general complexity of fluvial systems. It follows from the concept of complex response that synoptic and short-term historical views of rivers will often give misleading understanding of future behavior. Nevertheless, broadly trained geomorphologists can address questions involving complex natural systems by drawing from a tool box that commonly includes the principles and methods of geology, hydrology, hydraulics, engineering, and ecology.

  1. Single incision laparoscopic surgery (SILS) inguinal hernia repair - recent clinical experiences of this novel technique.

    Science.gov (United States)

    Yussra, Y; Sutton, P A; Kosai, N R; Razman, J; Mishra, R K; Harunarashid, H; Das, S

    2013-01-01

    Inguinal hernia remains the most commonly encountered surgical problem. Various methods of repair have been described, and the most suitable one debated. Single port access (SPA) surgery is a rapidly evolving field, and has the advantage of affording 'scarless' surgery. Single incision laparoscopic surgery (SILS) for inguinal hernia repair is seen to be feasible in both total extraperitoneal (TEP) and transabdominal pre-peritoneal (TAPP) approaches. Data and peri-operative information on both of these however are limited. We aimed to review the clinical experience, feasibility and short term complications related to laparoscopic inguinal hernia repair via single port access. A literature search was performed using Google Scholar, Springerlink Library, Highwire Press, Surgical Endoscopy Journal, World Journal of Surgery and Medscape. The following search terms were used: laparoscopic hernia repair, TAPP, TEP, single incision laparoscopic surgery (SILS). Fourteen articles in English language related to SILS inguinal hernia repair were identified. Nine articles were related to TEP repair and the remaining 5 to TAPP. A total of 340 patients were reported within these studies: 294 patients having a TEP repair and 46 a TAPP. Only two cases of recurrence were reported. Various ports have been utilized, including the SILS port, Tri-Port and a custom- made port using conventional laparoscopic instruments. The duration of surgery was 40-100 minutes and the average length of hospital stay was one day. Early outcomes of this novel technique show it to be feasible, safe and with potentially better cosmetic outcome.

  2. Geomorphic Unit Tool (GUT): Applications of Fluvial Mapping

    Science.gov (United States)

    Kramer, N.; Bangen, S. G.; Wheaton, J. M.; Bouwes, N.; Wall, E.; Saunders, C.; Bennett, S.; Fortney, S.

    2017-12-01

    Geomorphic units are the building blocks of rivers and represent distinct habitat patches for many fluvial organisms. We present the Geomorphic Unit Toolkit (GUT), a flexible GIS geomorphic unit mapping tool, to generate maps of fluvial landforms from topography. GUT applies attributes to landforms based on flow stage (Tier 1), topographic signatures (Tier 2), geomorphic characteristics (Tier 3) and patch characteristics (Tier 4) to derive attributed maps at the level of detail required by analysts. We hypothesize that if more rigorous and consistent geomorphic mapping is conducted, better correlations between physical habitat units and ecohydraulic model results will be obtained compared to past work. Using output from GUT for coarse bed tributary streams in the Columbia River Basin, we explore relationships between salmonid habitat and geomorphic spatial metrics. We also highlight case studies of how GUT can be used to showcase geomorphic impact from large wood restoration efforts. Provided high resolution topography exists, this tool can be used to quickly assess changes in fluvial geomorphology in watersheds impacted by human activities.

  3. Reservoirs as hotspots of fluvial carbon cycling in peatland catchments.

    Science.gov (United States)

    Stimson, A G; Allott, T E H; Boult, S; Evans, M G

    2017-02-15

    Inland water bodies are recognised as dynamic sites of carbon processing, and lakes and reservoirs draining peatland soils are particularly important, due to the potential for high carbon inputs combined with long water residence times. A carbon budget is presented here for a water supply reservoir (catchment area~9km 2 ) draining an area of heavily eroded upland peat in the South Pennines, UK. It encompasses a two year dataset and quantifies reservoir dissolved organic carbon (DOC), particulate organic carbon (POC) and aqueous carbon dioxide (CO 2 (aq)) inputs and outputs. The budget shows the reservoir to be a hotspot of fluvial carbon cycling, as with high levels of POC influx it acts as a net sink of fluvial carbon and has the potential for significant gaseous carbon export. The reservoir alternates between acting as a producer and consumer of DOC (a pattern linked to rainfall and temperature) which provides evidence for transformations between different carbon species. In particular, the budget data accompanied by 14 C (radiocarbon) analyses provide evidence that POC-DOC transformations are a key process, occurring at rates which could represent at least ~10% of the fluvial carbon sink. To enable informed catchment management further research is needed to produce carbon cycle models more applicable to these environments, and on the implications of high POC levels for DOC composition. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Channel incision and suspended sediment delivery at Caspar Creek, Mendocino County, California

    Science.gov (United States)

    Nicholas J. Dewey; Thomas E. Lisle; Leslie M. Reid

    2003-01-01

    Tributary and headwater valleys in the Caspar Creek watershed,in coastal Mendocino County, California,show signs of incision along much of their lengths.An episode of incision followed initial-entry logging which took place between 1860 and 1906. Another episode of incision cut into skid-trails created for second-entry logging in the 1970's.

  5. Monitoring fluvial erosion of the Oso landslide, Washington, using repeat Structure-from-Motion photogrammetry

    Science.gov (United States)

    Anderson, S. W.; Magirl, C. S.; Keith, M. K.

    2015-12-01

    On March 22, 2014, the Oso landslide, located in northwestern Washington State, catastrophically mobilized about 8 million m3 of mixed glacial sediment, creating a valley-wide blockage that impounded the North Fork Stillaguamish River to a height of 8 m. The river overtopped the landslide blockage within several days and incised a new channel through predominately fine-grained, cohesive glaciolacustrine sediment in the center of the deposit. Our research focuses on the evolution of this new channel. Using a consumer-grade digital camera mounted on a fixed wing-aircraft, we used structure-from-motion (SfM) photogrammetry to produce 25 cm digital elevation models (DEMs) of the channel at one-month intervals between November 2014 and July 2015. A large RTK GPS validation dataset and inter-survey comparisons documents sub-decimeter vertical and horizontal accuracies. In combination with aerial lidar surveys acquired in March and April 2014, this dataset provides a uniquely resolved look at the erosion of a landslide dam. The newly-formed channel incised rapidly, lowering to within a meter of its pre-slide elevation by May 2014 despite modest flows. During high flows of the 2014-2015 winter flood season, erosion was dominated by channel widening of tens of meters with an overall stable planform. Incision fully returned the channel to pre-slide elevations by December 2014. A total of 510,000 +/- 50,000 m3 of material was eroded between March 2014 and July 2015, split evenly between the initial period of incision and the later period of widening. Sediment yield and channel morphology showed asymptotic trends towards stability. Measurements of deposit bulk density and grain size allowed conversion of volumetric sediment yields to mass yields by size classes. Over the 16 months after the slide, the river eroded about 0.82 +/- 0.1 Mt of sediment, of which 0.78 Mt was finer than 2mm. This yield agrees within 15% of an independent estimate based on concurrent sediment gaging

  6. Penetrating and Intrastromal Corneal Arcuate Incisions in Rabbit and Human Cadaver Eyes: Manual Diamond Blade and Femtosecond Laser-Created Incisions.

    Science.gov (United States)

    Gray, Brad; Binder, Perry S; Huang, Ling C; Hill, Jim; Salvador-Silva, Mercedes; Gwon, Arlene

    2016-07-01

    To compare morphologic differences between freehand diamond or femtosecond laser-assisted penetrating and intrastromal arcuate incisions. Freehand diamond blade, corneal arcuate incisions (180° apart, 60° arc lengths) and 150 kHz femtosecond laser (80% scheimpflug pachymetry depth corneal thickness) arcuate incisions were performed in rabbits. Intrastromal arcuate incisions (100 μm above Descemet's membrane, 100 μm below epithelium) were performed in rabbit corneas (energy 1.2 μJ, spot line separation 3 × 3 μm, 90° side cut angle). Eyes were examined by slit lamp and light microscopy up to 47 days post-procedure. Freehand diamond blade penetrating incisions, and femtosecond laser penetrating and intrastromal arcuate incisions (energy 1.8 μJ, spot line separation 2 × 2 μm) were performed in cadaver eyes. Optical coherence tomography was performed immediately after surgery and the corneas were fixed for light scanning and transmission electron microscopy. The rabbit model showed anterior stromal inflammation with epithelial hyperplasia in penetrating blade and laser penetrating wounds. The laser intrastromal and penetrating incisions showed localized constriction of the stromal layers of the cornea near the wound. In cadaver eyes, penetrating wound morphology was similar between blade and laser whereas intrastromal wounds did not affect the cornea above or below incisions. Penetrating femtosecond laser arcuate incisions have more predictable and controlled outcomes shown by less post-operative scarring than incisions performed with a diamond blade. Intrastromal incisions do not affect uncut corneal layers as demonstrated by histopathology. The femtosecond laser has significant advantages in its ability to make intrastromal incisions which are not achievable by traditional freehand or mechanical diamond blades.

  7. Late Pleistocene sea-level changes recorded in tidal and fluvial deposits from Itaubal Formation, onshore portion of the Foz do Amazonas Basin, Brazil

    Directory of Open Access Journals (Sweden)

    Isaac Salém Alves Azevedo Bezerra

    Full Text Available ABSTRACTThe Pleistocene deposits exposed in the Amapá Coastal Plain (onshore portion of the Foz do Amazonas Basin, northeastern South America were previously interpreted as Miocene in age. In this work, they were named as "Itaubal Formation" and were included in the quaternary coastal history of Amazonia. The study, through facies and stratigraphic analyses in combination with optically stimulated luminescence (single and multiple aliquot regeneration, allowed interpreting this unit as Late Pleistocene tidal and fluvial deposits. The Itaubal Formation, which unconformably overlies strongly weathered basement rocks of the Guianas Shield, was subdivided into two progradational units, separated by an unconformity related to sea-level fall, here named as Lower and Upper Units. The Lower Unit yielded ages between 120,600 (± 12,000 and 70,850 (± 6,700 years BP and consists of subtidal flat, tide-influenced meandering stream and floodplain deposits, during highstand conditions. The Upper Unit spans between 69,150 (± 7,200 and 58,150 (± 6,800 years BP and is characterized by braided fluvial deposits incised in the Lower Unit, related to base-level fall; lowstand conditions remained until 23,500 (± 3,000 years BP. The studied region was likely exposed during the Last Glacial Maximum and then during Holocene, covered by tidal deposits influenced by the Amazon River.

  8. Fluvial landscape development in the southwestern Kalahari during the Holocene - Chronology and provenance of fluvial deposits in the Molopo Canyon

    DEFF Research Database (Denmark)

    Ramisch, Arne; Bens, Oliver; Buylaert, Jan-Pieter

    2017-01-01

    are sparse and often discontinuous. Hence, little is known about Holocene environmental change in this region. This study focuses on reconstructing paleoenvironmental change from the timing and provenance of fluvial deposits located within the Molopo Canyon, which connects the southern Kalahari drainage...... to the deposition of alluvial fills. These results suggest that the southern Kalahari Drainage remained endorheic and therefore disconnected from the Orange River throughout the Holocene....

  9. Fluvial deposits as an archive of early human activity: Progress during the 20 years of the Fluvial Archives Group

    Science.gov (United States)

    Chauhan, Parth R.; Bridgland, David R.; Moncel, Marie-Hélène; Antoine, Pierre; Bahain, Jean-Jacques; Briant, Rebecca; Cunha, Pedro P.; Despriée, Jackie; Limondin-Lozouet, Nicole; Locht, Jean-Luc; Martins, Antonio A.; Schreve, Danielle C.; Shaw, Andrew D.; Voinchet, Pierre; Westaway, Rob; White, Mark J.; White, Tom S.

    2017-06-01

    Fluvial sedimentary archives are important repositories for Lower and Middle Palaeolithic artefacts throughout the 'Old World', especially in Europe, where the beginning of their study coincided with the realisation that early humans were of great antiquity. Now that many river terrace sequences can be reliably dated and correlated with the globally valid marine isotope record, potentially useful patterns can be recognized in the distribution of the find-spots of the artefacts that constitute the large collections that were assembled during the years of manual gravel extraction. This paper reviews the advances during the past two decades in knowledge of hominin occupation based on artefact occurrences in fluvial contexts, in Europe, Asia and Africa. As such it is an update of a comparable review in 2007, at the end of IGCP Project no. 449, which had instigated the compilation of fluvial records from around the world during 2000-2004, under the auspices of the Fluvial Archives Group. An overarching finding is the confirmation of the well-established view that in Europe there is a demarcation between handaxe making in the west and flake-core industries in the east, although on a wider scale that pattern is undermined by the increased numbers of Lower Palaeolithic bifaces now recognized in East Asia. It is also apparent that, although it seems to have appeared at different places and at different times in the later Lower Palaeolithic, the arrival of Levallois technology as a global phenomenon was similarly timed across the area occupied by Middle Pleistocene hominins, at around 0.3 Ma.

  10. A laser profilometry technique for monitoring fluvial dike breaching in laboratory experiments

    Science.gov (United States)

    Dewals, Benjamin; Rifai, Ismail; Erpicum, Sébastien; Archambeau, Pierre; Violeau, Damien; Pirotton, Michel; El kadi Abderrezzak, Kamal

    2017-04-01

    laser are merged to generate a cloud of points. The DLT-based image processing method uses control points and reference axes, so that no prior knowledge is needed on the position, orientation and intrinsic characteristics of the camera, nor on the laser position. Refraction of the light and laser rays across the water surface needs to be taken into account, because the dike is partially submerged during the experiments. An ad hoc correction is therefore applied using the Snell-Descartes law. For this purpose, planar approximations are used to describe the shape of the water surface. In the presentation, we will discuss the resulting uncertainty and will detail the validation of the developed method based on configurations of known geometry with various complexity. The presented laser profilometry technique allows for a rapid non-intrusive measurement of the dike geometry evolution. It is readily available for laboratory experiments and has proven its performance (Rifai et al. 2017). Further adjustments are needed for its application to cohesive dike material due to the reduced visibility resulting from the higher turbidity of water. References Frank, P.-J., Hager, W.H. (2014). Spatial dike breach: Accuracy of photogrammetric measurement system. Proc. of the International Conference on Fluvial Hydraulics, River Flow 2014, 1647-1654. Pickert, G., Weitbrecht, V., Bieberstein A. (2011). Beaching of overtopped river embankments controlled by apparent cohesion. Journal of Hydraulic Research 49:143-156. Rifai, I., Erpicum, S., Archambeau, P., Violeau, D., Pirotton, M., El kadi Abderrezzak, K., Dewals, B. (2016). Monitoring topography of laboratory fluvial dike models subjected to breaching based on a laser profilometry technique. Proc. of the International Symposium on River Sedimentation (ISRS): Stuttgart, 19-22 September 2016. Rifai, I., Erpicum, S., Archambeau, P., Violeau, D., Pirotton, M., El kadi Abderrezzak, K., Dewals, B. (2017). Overtopping induced failure of non

  11. Incisive papilla and positions of maxillary anterior teeth among ...

    African Journals Online (AJOL)

    Results: One hundred and twelve maxillary casts generated from participants aged 18-35 years (mean age 22.39±2.00 years), with well aligned arches were studied. The maxillary central incisor exhibited a mean of 14.93±1.52mm from the posterior limit of the incisive papilla while the inter-canine line scored a mean of ...

  12. A manual to identify sources of fluvial sediment

    Science.gov (United States)

    Gellis, Allen C.; Fitzpatrick, Faith A.; Schubauer-Berigan, Joseph

    2016-01-01

    sediment sources early in the design of the sediment budget will help later in deciding which tools are necessary to monitor erosion and/or deposition at these sources. Tools can range from rapid inventories to estimate the sediment budget or quantifying sediment erosion, deposition, and export through more rigorous field monitoring. In either approach, data are gathered and erosion and deposition calculations are determined and compared to the sediment export with a description of the error uncertainty. Findings are presented to local stakeholders and management officials.Sediment fingerprinting is a technique that apportions the sources of fine-grained sediment in a watershed using tracers or fingerprints. Due to different geologic and anthropogenic histories, the chemical and physical properties of sediment in a watershed may vary and often represent a unique signature (or fingerprint) for each source within the watershed. Fluvial sediment samples (the target sediment) are also collected and exhibit a composite of the source properties that can be apportioned through various statistical techniques. Using an unmixing-model and error analysis, the final apportioned sediment is determined.

  13. Manual small incision extracapsular cataract surgery in Australia.

    Science.gov (United States)

    van Zyl, Lourens; Kahawita, Shyalle; Goggin, Michael

    2014-11-01

    Examination of the results and describing the technique of manual small incision extracapsular cataract extraction on patients with advanced cataracts in urban Australia. A descriptive case series. Thirty-eight patients at three public hospitals, one tertiary and two secondary ophthalmic units in urban Australia. Forty eyes with dense mature cataracts with hand movement vision or worse underwent a planned manual small incision extracapsular cataract extraction instead of traditional phaco-emulsification. Postoperative visual aquity, surgically induced astigmatism and complications. Seventy-eight per cent of patients had an uncorrected visual acuity of 6/12 or better on the first postoperative day. Eighty-three per cent of patients had a distance corrected visual acuity of 6/9 or better 3 months postoperatively. One case was complicated by a posterior capsule rupture. No cases of endophthalmitis were reported. The summated vector mean of the surgically induced astigmatism was 0.089D at 93°. Manual small incision extracapsular cataract extraction is an efficacious cataract surgery technique with good visual outcome and is a safe alternative to phaco-emulsification in suitable cases in a first-world setting. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

  14. Single incision thoracoscopic sympathectomy for palmar and axillary hyperhidrosis

    Directory of Open Access Journals (Sweden)

    Aram Baram

    2014-02-01

    Full Text Available Background: Primary hyperhidrosis is characterized by excessive sweating beyond physiological needs. It is a common disease (incidence 2.8% that causes intense discomfort for patients. In the last decade, advantages of Single-Incision Thoracoscopic Sympathectomy have become clear, particularly in decreasing morbidity of sympathectomy. Patients and methods: From January 2010 to December 2012, 39 patients (29 females and 10 males with primary palmar or axillary hyperhidrosis were treated by thoracoscopic sympathectomy. The age ranged from 18 to 40 years with a mean of 26.28 years. We used single incision thoracoscopic electrocoagulation through 10 mm incision for thoracic sympathetic chain (T2–T4. Results: The mean follow-up was 23.6 ± 14.2 months (range = 4–24 months. A total of 97.42% of patients were satisfied with the results. A total of 72.5% of patients had cure, one patient (2.5% and another patient (2.5% presented with recurrent axillary hyperhidrosis. The morbidity was 10.2% with no mortality. Percentage of compensatory sweating and gustatory sweating were 5.1% (p = .353 and 2.5% (p = .552, respectively. The result of sympathectomy in patients with both palmar and axillary hyperhidrosis was significantly better (17, 43.58% compared to palmar type (14, 35.89% or axillary type (7, 17.94%. Conclusion: Thoracoscopic sympathectomy is a simple, safe, and cost-effective therapy with good results and low complications.

  15. Characterization of a fluvial aquifer at a range of depths and scales: the Triassic St Bees Sandstone Formation, Cumbria, UK

    Science.gov (United States)

    Medici, Giacomo; West, L. J.; Mountney, N. P.

    2018-03-01

    Fluvial sedimentary successions represent porous media that host groundwater and geothermal resources. Additionally, they overlie crystalline rocks hosting nuclear waste repositories in rift settings. The permeability characteristics of an arenaceous fluvial succession, the Triassic St Bees Sandstone Formation in England (UK), are described, from core-plug to well-test scale up to 1 km depth. Within such lithified successions, dissolution associated with the circulation of meteoric water results in increased permeability ( K 10-1-100 m/day) to depths of at least 150 m below ground level (BGL) in aquifer systems that are subject to rapid groundwater circulation. Thus, contaminant transport is likely to occur at relatively high rates. In a deeper investigation (> 150 m depth), where the aquifer has not been subjected to rapid groundwater circulation, well-test-scale hydraulic conductivity is lower, decreasing from K 10-2 m/day at 150-400 m BGL to 10-3 m/day down-dip at 1 km BGL, where the pore fluid is hypersaline. Here, pore-scale permeability becomes progressively dominant with increasing lithostatic load. Notably, this work investigates a sandstone aquifer of fluvial origin at investigation depths consistent with highly enthalpy geothermal reservoirs ( 0.7-1.1 km). At such depths, intergranular flow dominates in unfaulted areas with only minor contribution by bedding plane fractures. However, extensional faults represent preferential flow pathways, due to presence of high connective open fractures. Therefore, such faults may (1) drive nuclear waste contaminants towards the highly permeable shallow (< 150 m BGL) zone of the aquifer, and (2) influence fluid recovery in geothermal fields.

  16. An Assessment of Hydrology, Fluvial Geomorphology, and Stream Ecology in the Cardwell Branch Watershed, Nebraska, 2003-04

    Science.gov (United States)

    Rus, David L.; Dietsch, Benjamin J.; Woodward, Brenda K.; Fry, Beth E.; Wilson, Richard C.

    2007-01-01

    An assessment of the 16.3-square-mile Cardwell Branch watershed characterized the hydrology, fluvial geomorphology, and stream ecology in 2003-04. The study - performed by the U.S. Geological Survey in cooperation with the City of Lincoln, Nebraska, and the Lower Platte South Natural Resources District - focused on the 7.7-square-mile drainage downstream from Yankee Hill Reservoir. Hydrologic and hydraulic models were developed using the Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS) of the U.S. Army Corps of Engineers Hydraulic Engineering Center. Estimates of streamflow and water-surface elevation were simulated for 24-hour-duration design rainstorms ranging from a 50-percent frequency to a 0.2-percent frequency. An initial HEC-HMS model was developed using the standardized parameter estimation techniques associated with the Soil Conservation Service curve number technique. An adjusted HEC-HMS model also was developed in which parameters were adjusted in order for the model output to better correspond to peak streamflows estimated from regional regression equations. Comparisons of peak streamflow from the two HEC-HMS models indicate that the initial HEC-HMS model may better agree with the regional regression equations for higher frequency storms, and the adjusted HEC-HMS model may perform more closely to regional regression equations for larger, rarer events. However, a lack of observed streamflow data, coupled with conflicting results from regional regression equations and local high-water marks, introduced considerable uncertainty into the model simulations. Using the HEC-RAS model to estimate water-surface elevations associated with the peak streamflow, the adjusted HEC-HMS model produced average increases in water-surface elevation of 0.2, 1.1, and 1.4 feet for the 50-, 1-, and 0.2-percent-frequency rainstorms, respectively, when compared to the initial HEC-HMS model. Cross-sectional surveys and field assessments conducted between

  17. In vivo architectural analysis of clear corneal incisions using anterior segment optical coherence tomography.

    Science.gov (United States)

    Dupont-Monod, Sylvère; Labbé, Antoine; Fayol, Nicolas; Chassignol, Alexis; Bourges, Jean-Louis; Baudouin, Christophe

    2009-03-01

    To use anterior segment optical coherence tomography (AS-OCT) to analyze the in vivo architecture of clear corneal incisions after phacoemulsification using different techniques. Department of Ophthalmology, Quinze-Vingts National Ophthalmology Hospital, Paris, France. This prospective observational study analyzed clear corneal incisions used in phacoemulsification. All wounds were evaluated 1 day and 8 days postoperatively by AS-OCT (Visante). Incision architecture and pachymetry at the wound level were analyzed. Thirty-five clear corneal incisions were analyzed. Six eyes had 2.75 mm coaxial phacoemulsification, 19 had 2.20 mm microincision coaxial phacoemulsification, and 10 had 1.30 mm bimanual microincision phacoemulsification. The 1.30 mm incision had a straight-line configuration. The 2.20 mm and 2.75 mm incisions had an arcuate configuration. The angles of incidence of 1.30 mm incisions were greater than those of 2.20 mm incisions (P<.001). All incisions had slight corneal edema limited to the incision area. The edema was slightly greater around 1.30 mm incisions (mean pachymetry 1143 microm +/- 140 [SD]) than around 2.20 mm incisions (mean 1012 +/- 101 microm) (P = .001). Bimanual procedures had satisfactory endothelial apposition in the enlarged areas, where stromal edema was less than that surrounding the unenlarged 1.30 mm incisions. The 3 phacoemulsification techniques induced gaping of the endothelial edge, minor inadequate endothelial apposition, and mild stromal edema in the area of the clear corneal incisions. Bimanual microincision sleeveless phacoemulsification may alter the wound slightly more than coaxial 2.75 mm and microcoaxial 2.20 mm sleeved-tip phacoemulsification.

  18. Fluvial response to abrupt global warming at the Palaeocene/Eocene boundary.

    Science.gov (United States)

    Foreman, Brady Z; Heller, Paul L; Clementz, Mark T

    2012-11-01

    Climate strongly affects the production of sediment from mountain catchments as well as its transport and deposition within adjacent sedimentary basins. However, identifying climatic influences on basin stratigraphy is complicated by nonlinearities, feedback loops, lag times, buffering and convergence among processes within the sediment routeing system. The Palaeocene/Eocene thermal maximum (PETM) arguably represents the most abrupt and dramatic instance of global warming in the Cenozoic era and has been proposed to be a geologic analogue for anthropogenic climate change. Here we evaluate the fluvial response in western Colorado to the PETM. Concomitant with the carbon isotope excursion marking the PETM we document a basin-wide shift to thick, multistoried, sheets of sandstone characterized by variable channel dimensions, dominance of upper flow regime sedimentary structures, and prevalent crevasse splay deposits. This progradation of coarse-grained lithofacies matches model predictions for rapid increases in sediment flux and discharge, instigated by regional vegetation overturn and enhanced monsoon precipitation. Yet the change in fluvial deposition persisted long after the approximately 200,000-year-long PETM with its increased carbon dioxide levels in the atmosphere, emphasizing the strong role the protracted transmission of catchment responses to distant depositional systems has in constructing large-scale basin stratigraphy. Our results, combined with evidence for increased dissolved loads and terrestrial clay export to world oceans, indicate that the transient hyper-greenhouse climate of the PETM may represent a major geomorphic 'system-clearing event', involving a global mobilization of dissolved and solid sediment loads on Earth's surface.

  19. Fluvial geomorphology: where do we go from here?

    Science.gov (United States)

    Smith, Derald G.

    1993-07-01

    The evolution of geomorphology and in particular, fluvial geomorphology, is at a crossroads. Currently, the discipline is dismally organized, without focus or direction, and is practised by individualists who rarely collaborate in numbers significant enough to generate major research initiatives. If the discipline is to mature and to prosper, we must make some very difficult decisions that will require major changes in our ways of thinking and operating. Either the field stays in its current operational mode and becomes a backwater science, or it moves forward and adopts the ways of the more competitive sectors of the earth and biosciences. For the discipline to evolve, fluvial geomorphologists must first organize an association within North America or at the international level. The 3rd International Geomorphology Conference may be a start, but within that organization we must develop our own divisional and/or regional organizations. Within the Quaternary geology/geomorphology divisions of the Geological Socieity of America (GSA), Association of American Geographers (AAG), American Geophysical Union (AGU) and British Geomorphology Research Group (BGRG) the voice of fluvial geomorphology is lost in a sea of diverse and competitive interests, though there is reason for hope resulting from some recent initiatives. In Canada, we have no national geomorphology organization per se; our closest organization is Canqua (Canadian Quaternary Association). Next, fluvial researchers must collaborate, by whatever means, to develop "scientific critical mass" in order to generate ideas and long-range goals of modest and major scientific importance. These projects will help secure major research funding without which, research opportunities will diminish and initiating major new research will become nearly impossible. Currently, we are being surpassed by the glaciologists, remote sensors, ecologists, oceanographers, climatologists-atmospheric researchers and some Quaternary

  20. La géoarchéologie fluviale

    Directory of Open Access Journals (Sweden)

    Gilles Arnaud-Fassetta

    2008-03-01

    Full Text Available Les recherches des hydrogéomorphologues ont des applications nombreuses dans le vaste champ des sciences géoarchéologiques. Elles fournissent des réponses précises sur la façon dont l’environnement des anciens lieux de passage et de vie humaine a évolué. Le propos n’est pas seulement de définir les causes des grands changements environnementaux, mais aussi de juger de la vulnérabilité sociétale face aux contraintes hydroclimatiques. Pour cela, les méthodes d’étude doivent nécessairement prendre en compte les trois facettes de la géomorphologie fluviale : la paléohydrographie, la paléohydrologie et la paléohydraulique. La pertinence de cette approche est montrée en milieu rural et urbain dans les plaines deltaïques du Rhône (France du Sud et de l’Isonzo (Italie du Nord.Current research led by hydrogeomorphologists has numerous applications in the vast field of geoarchaeological sciences. It brings precise answers on environmental characteristics around the ancient places of passage and human life. The goal is not only to define the causes of global environmental changes, but also to precise the links between river dynamics and human societies in terms of fluvial risk. Therefore, the studied methods should simultaneously take into account the three facets of the fluvial geomorphology, i.e., the palaeohydrography, the palaeohydrology, and the palaeohydraulics. The pertinence of this combinatorial approach is deduced from the work of the author led both in rural and urban areas of the deltaic plains of the Rhône (South of France and Isonzo (northern Italy rivers.

  1. Assessing the Effects of Climate on Global Fluvial Discharge Variability

    Science.gov (United States)

    Hansford, M. R.; Plink-Bjorklund, P.

    2017-12-01

    Plink-Bjorklund (2015) established the link between precipitation seasonality and river discharge variability in the monsoon domain and subtropical rivers (see also Leier et al, 2005; Fielding et al., 2009), resulting in distinct morphodynamic processes and a sedimentary record distinct from perennial precipitation zone in tropical rainforest zone and mid latitudes. This study further develops our understanding of discharge variability using a modern global river database created with data from the Global Runoff Data Centre (GRDC). The database consists of daily discharge for 595 river stations and examines them using a series of discharge variability indexes (DVI) on different temporal scales to examine how discharge variability occurs in river systems around the globe. These indexes examine discharge of individual days and monthly averages that allows for comparison of river systems against each other, regardless of size of the river. Comparing river discharge patterns in seven climate zones (arid, cold, humid subtropics, monsoonal, polar, rainforest, and temperate) based off the Koppen-Geiger climate classifications reveals a first order climatic control on discharge patterns and correspondingly sediment transport. Four groupings of discharge patterns emerge when coming climate zones and DVI: persistent, moderate, seasonal, and erratic. This dataset has incredible predictive power about the nature of discharge in fluvial systems around the world. These seasonal effects on surface water supply affects river morphodynamics and sedimentation on a wide timeframe, ranging from large single events to an inter-annual or even decadal timeframe. The resulting sedimentary deposits lead to differences in fluvial architecture on a range of depositional scales from sedimentary structures and bedforms to channel complex systems. These differences are important to accurately model for several reasons, ranging from stratigraphic and paleoenviromental reconstructions to more

  2. Hydrodynamic and sedimentological controls governing formation of fluvial levees

    Science.gov (United States)

    Johnston, G. H.; Edmonds, D. A.; David, S. R.; Czuba, J. A.

    2017-12-01

    Fluvial levees are familiar features found on the margins of river channels, yet we know little about what controls their presence, height, and shape. These attributes of levees are important because they control sediment transfer from channel to floodplain and flooding patterns along a river system. Despite the familiarity and importance of levees, there is a surprising lack of basic geomorphic data on fluvial levees. Because of this we seek to understand: 1) where along rivers do levees tend to occur?; 2) what geomorphic and hydrodynamic variables control cross-sectional shape of levees? We address these questions by extracting levee shape from LiDAR data and by collecting hydrodynamic and sedimentological data from reaches of the Tippecanoe River, the White River, and the Muscatatuck River, Indiana, USA. Fluvial levees are extracted from a 1.5-m resolution LiDAR bare surface model and compared to hydrological, sedimentological, and geomorphological data from USGS stream gages. We digitized banklines and extracted levee cross-sections to calculate levee slope, taper, height, e-folding length, and e-folding width. To answer the research questions, we performed a multivariable regression between the independent variables—channel geometry, sediment grain size and concentration, flooding conditions, and slope—and the dependent levee variables. We find considerable variation in levee presence and shape in our field data. On the Muscatatuck River levees occur on 30% of the banks compared to 10% on the White River. Moreover, levees on the Muscatatuck are on average 3 times wider than the White River. This is consistent with the observation that the Muscatatuck is finer-grained compared to the White River and points to sedimentology being an important control on levee geomorphology. Future work includes building a morphodynamic model to understand how different hydrodynamic and geomorphic conditions control levee geometry.

  3. Introduction to the special issue on discontinuity of fluvial systems

    Science.gov (United States)

    Burchsted, Denise; Daniels, Melinda; Wohl, Ellen E.

    2014-01-01

    Fluvial systems include natural and human-created barriers that modify local base level; as such, these discontinuities alter the longitudinal flux of water and sediment by storing, releasing, or changing the flow path of those materials. Even in the absence of distinct barriers, fluvial systems are typically discontinuous and patchy. The size of fluvial discontinuities ranges across scales from 100 m, such as riffles, to 104 m, such as lava dams or major landslides. The frequency of occurrence appears to be inversely related to size, with creation and failure of the small features, such as beaver dams, occurring on a time scale of 100 to 101 years and a frequency of occurrence at scales as low as 101 m. In contrast, larger scale discontinuities, such as lava dams, can last for time scales up to 105 years and have a frequency of occurrence of approximately 104 m. The heterogeneity generated by features is an essential part of river networks and should be considered as part of river management. Therefore, we suggest that "natural" dams are a useful analog for human dams when evaluating options for river restoration. This collection of papers on the studies of natural dams includes bedrock barriers, log jams and beaver dams. The collection also addresses the discontinuity generated by a floodplain — in the absence of an obvious barrier in the channel — and tools for evaluation of riverbed heterogeneity. It is completed with a study of impact of human dams on floodplain sedimentation. These papers will help geomorphologists and river managers understand the factors that control river heterogeneity across scales and around the world.

  4. Variability in fluvial geomorphic response to anthropogenic disturbance

    Science.gov (United States)

    Verstraeten, Gert; Broothaerts, Nils; Van Loo, Maarten; Notebaert, Bastiaan; D'Haen, Koen; Dusar, Bert; De Brue, Hanne

    2017-10-01

    Humans have greatly impacted the processes and intensities of erosion, sediment transport and storage since the introduction of agriculture. In many regions around the world, accelerated floodplain sedimentation can be related to increases in human pressure on the environment. However, the relation between the intensity of anthropogenic disturbance and the magnitude of change in fluvial sediment dynamics is not straightforward and often non-linear. Here, we review a number of case studies from contrasting environmental settings in the European loess belt, the Eastern Mediterranean mountain ranges and the eastern USA. Detailed field-based sediment archive studies and sediment budgets covering time periods ranging from 200 to over 5000 year, as well as the use of pollen and sediment provenance techniques, show that no overarching concept of changes in floodplain sedimentation following anthropogenic disturbance can be established. Slope-channel (dis)connectivity controls the existence of thresholds or tipping points that need to be crossed before significant changes in downstream sediment dynamics are recorded following human impact. This coupling can be related to characteristics of human pressure such as its duration, intensity and spatial patterns, but also to the geomorphic and tectonic setting. Furthermore, internal feedback mechanisms, such as those between erosion and soil thickness, further complicate the story. All these factors controlling the propagation of sediment from eroding hillslopes to river channels vary between regions. Hence, only unique patterns of fluvial geomorphic response can be identified. As a result, unravelling the human impact from current-day sediment archives and predicting the impact of future human disturbances on fluvial sediment dynamics remain a major challenge. This has important implications for interpreting contemporary sediment yields as well as downstream sediment records in large floodplains, deltas and the marine

  5. Lacustrine-fluvial interactions in Australia's Riverine Plains

    Science.gov (United States)

    Kemp, Justine; Pietsch, Timothy; Gontz, Allen; Olley, Jon

    2017-06-01

    Climatic forcing of fluvial systems has been a pre-occupation of geomorphological studies in Australia since the 1940s. In the Riverine Plain, southeastern Australia, the stable tectonic setting and absence of glaciation have combined to produce sediment loads that are amongst the lowest in the world. Surficial sediments and landforms exceed 140,000 yr in age, and geomorphological change recorded in the fluvial, fluvio-lacustrine and aeolian features have provided a well-studied record of Quaternary environmental change over the last glacial cycle. The region includes the Willandra Lakes, whose distinctive lunette lakes preserve a history of water-level variations and ecological change that is the cornerstone of Australian Quaternary chronostratigraphy. The lunette sediments also contain an ancient record of human occupation that includes the earliest human fossils yet found on the Australian continent. To date, the lake-level and palaeochannel records in the Lachlan-Willandra system have not been fully integrated, making it difficult to establish the regional significance of hydrological change. Here, we compare the Willandra Lakes environmental record with the morphology and location of fluvial systems in the lower Lachlan. An ancient channel belt of the Lachlan, Willandra Creek, acted as the main feeder channel to Willandra Lakes before channel avulsion caused the lakes to dry out in the late Pleistocene. Electromagnetic surveys, geomorphological and sedimentary evidence are used to reconstruct the evolution of the first new channel belt following the avulsion. Single grain optical dating of floodplain sediments indicates that sedimentation in the new Middle Billabong Palaeochannel had commenced before 18.4 ± 1.1 ka. A second avulsion shifted its upper reaches to the location of the present Lachlan River by 16.2 ± 0.9 ka. The timing of these events is consistent with palaeohydrological records reconstructed from Willandra Lakes and with the record of

  6. Large Fluvial Fans: Aspects of the Attribute Array

    Science.gov (United States)

    Wilkinson, Justin M.

    2015-01-01

    In arguing for a strict definition of the alluvial fan (coarse-grained with radii less than10 km, in mountain-front settings), Blair and McPherson (1994) proposed that there is no meaningful difference between large fluvial fans (LFF) and floodplains, because the building blocks of both are channel-levee-overbank deposits. Sediment bodies at the LFF scale (greater than 100 km long, fan-shaped in planform), are relatively unstudied although greater than 160 are now identified globally. The following perspectives suggest that the significance of LFF needs to be reconsidered.

  7. New Mesoscale Fluvial Landscapes - Seismic Geomorphology and Exploration

    Science.gov (United States)

    Wilkinson, M. J.

    2013-01-01

    Megafans (100-600 km radius) are very large alluvial fans that cover significant areas on most continents, the surprising finding of recent global surveys. The number of such fans and patterns of sedimentation on them provides new mesoscale architectures that can now be applied on continental fluvial depositional systems, and therefore on. Megafan-scale reconstructions underground as yet have not been attempted. Seismic surveys offer new possibilities in identifying the following prospective situations at potentially unsuspected locations: (i) sand concentrations points, (ii) sand-mud continuums at the mesoscale, (iii) paleo-valley forms in these generally unvalleyed landscapes, (iv) stratigraphic traps, and (v) structural traps.

  8. The extended minimal incision approach to midface rejuvenation.

    Science.gov (United States)

    Pontius, Allison T; Williams, Edwin F

    2005-08-01

    Recent major advancements in comprehensive facial rejuvenation have focused on management of midfacial aging. Multiple techniques have been described to treat the aging midface; the mere nature of so many approaches is evidence that no one technique has prevailed. Although the nasolabial region remains a challenge to correct, the approach described herein provides comprehensive rejuvenation of the midface, lateral brow, and jawline. The technique is performed via a minimal incision brow-lift approach and has been performed (with minor modifications) by the senior author in more than 650 patients over the past 9 years. The technique has proven to be safe, reliable, and effective.

  9. Fluvial biogeomorphology in the Anthropocene: Managing rivers and managing landscapes.

    Science.gov (United States)

    Viles, Heather

    2015-04-01

    Biogeomorphology considers the many, and often complex, interactions between ecological and geomorphological processes. The concept of the Anthropocene deserves greater attention by scientists working on biogeomorphology, as will be demonstrated in this talk though a focus on fluvial environments. Rivers and river systems have been the subject of long-term human interference and management across the world, often in the form of direct manipulation of biogeomorphic interactions. Up to the present three broadly-defined phases of the Anthropocene can be identified - the Palaeoanthropocene, the Industrial Revolution and the Great Acceleration. Each of these broad phases of the Anthropocene has different implications for fluvial biogeomorphology and river management. The nature and dynamics of tufa-depositing systems provide good examples of the differing Anthropocene situations and will be focused on in this talk. We may now be entering a fourth phase of the Anthropocene called 'Earth system stewardship'. In terms of better understanding and managing the biogeomorphic interactions within rivers in such a phase, an improved conceptualisation of the Anthropocene and the complex web of interactions between human, ecological and geomorphological processes is needed.

  10. Investigating fluvial pattern and delta-planform geometry based on varying intervals of flood and interflood

    Science.gov (United States)

    Rambo, J. E.; Kim, W.; Miller, K.

    2017-12-01

    Physical modeling of a delta's evolution can represent how changing the intervals of flood and interflood can alter a delta's fluvial pattern and geometry. Here we present a set of six experimental runs in which sediment and water were discharged at constant rates over each experiment. During the "flood" period, both sediment and water were discharged at rates of 0.25 cm3/s and 15 ml/s respectively, and during the "interflood" period, only water was discharged at 7.5 ml/s. The flood periods were only run for 30 minutes to keep the total volume of sediment constant. Run 0 did not have an interflood period and therefore ran with constant sediment and water discharge for the duration of the experiment.The other five runs had either 5, 10, or 15-min intervals of flood with 5, 10, or 15-min intervals of interflood. The experimental results show that Run 0 had the smallest topset area. This is due to a lack of surface reworking that takes place during interflood periods. Run 1 had 15-minute intervals of flood and 15-minute intervals of interflood, and it had the largest topset area. Additionally, the experiments that had longer intervals of interflood than flood had more elongated delta geometries. Wetted fraction color maps were also created to plot channel locations during each run. The maps show that the runs with longer interflood durations had channels occurring predominantly down the middle with stronger incisions; these runs produced deltas with more elongated geometries. When the interflood duration was even longer, however, strong channels started to occur at multiple locations. This increased interflood period allowed for the entire area over the delta's surface to be reworked, thus reducing the downstream slope and allowing channels to be more mobile laterally. Physical modeling of a delta allows us to predict a delta's resulting geometry given a set of conditions. This insight is needed especially with delta's being the home to many populations of people and

  11. Integration of fluvial erosion factors for predicting landslides along meandering rivers

    Science.gov (United States)

    Chen, Yi-chin; Chang, Kang-tsung; Ho, Jui-yi

    2015-04-01

    River incision and lateral erosion are important geomorphologic processes in mountainous areas of Taiwan. During a typhoon or storm event, the increase of water discharge, flow velocity, and sediment discharge enhances the power of river erosion on channel bank. After the materials on toe of hillslope were removed by river erosion, landslides were triggered at outer meander bends. Although it has been long expected that river erosion can trigger landslide, studies quantifying the effects of river erosion on landslide and the application of river erosion index in landslide prediction are still overlooked. In this study, we investigated the effect of river erosion on landslide in a particular meanders landscape of the Jhoukou River, southern Taiwan. We developed a semi-automatic model to separate meandering lines into several reach segments based on the inflection points and to calculate river erosion indexes, e.g. sinuosity of meander, stream power, and stream order, for each reach segment. This model, then, built the spatial relationship between the reaches and its corresponding hillslopes, of which the toe was eroded by the reach. Based on the spatial relationship, we quantified the correlations between these indexes and landslides triggered by Typhoon Morakot in 2009 to examine the effects of river erosion on landslide. The correlated indexes were then used as landslide predictors in logistic regression model. Results of the study showed that there is no significant correlation between landslide density and meander sinuosity. This may be a result of wider channel dispersing the erosion at a meandering reach. On the other hand, landslide density at concave bank is significantly higher than that at convex bank in the downstream (stream order > 3), but that is almost the same in the upstream (stream order bank. In contrast, river sediment in the downstream is an erosion agent eroding the concave bank laterally, but also depositing on the concave side and protecting

  12. Unraveling the Quaternary river incision in the Moselle valley (Rhenish Massif, Germany): new insights from cosmogenic nuclide dating (10Be/26Al) of the Main Terrace complex

    Science.gov (United States)

    Rixhon, Gilles; Cordier, Stéphane; Harmand, Dominique; May, Simon Matthias; Kelterbaum, Daniel; Dunai, Tibor; Binnie, Steven; Brückner, Helmut

    2014-05-01

    Throughout the whole river network of the Rhenish Massif, the terrace complex of the so-called Main Terrace forms the morphological transition between a wide upper palaeovalley (plateau valley) and a deeply incised lower valley. The youngest level of this Main Terrace complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature in the terrace flight; it is often used as a reference level to identify the start of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). The latter probably reflects the major tectonic pulse that affected the whole Massif and was related to an acceleration of the uplift rates (Demoulin & Hallot, 2009). The Main terraces are particularly well preserved in the lower Moselle valley and are characterized by a constant absolute elevation of their base along a 150 km-long reach. Despite that various hypotheses have been proposed to explain this horizontality (updoming, faulting...), all studies assumed an age of ca. 800 ka for the YMT, mainly based on the questionable extrapolation of palaeomagnetic data obtained in the Rhine valley. Therefore, a reliable chronological framework is still required to unravel the spatio-temporal characteristics of the Pleistocene evolution of the Moselle valley. In this study, we apply cosmogenic nuclide dating (10Be/26Al) to fluvial sediments pertaining to the Main Terrace complex or to the upper Middle Terraces. Several sites along the lower Moselle were sampled following two distinct sampling strategies: (i) depth profiles where the original terrace (palaeo-)surface is well preserved and did not experience much postdepositional burial (e.g., loess cover); and (ii) the isochron technique where the sediment thickness exceeds 3 m. Cosmogenic nuclide ages recently obtained for three rivers in the Meuse catchment in the western Rhenish Massif demonstrated that the Main Terraces were younger than expected and their abandonment was diachronic along the

  13. A Simple Method for Closure of Urethrocutaneous Fistula after Tubularized Incised Plate Repair: Preliminary Results.

    Science.gov (United States)

    Shirazi, Mehdi; Ariafar, Ali; Babaei, Amir Hossein; Ashrafzadeh, Abdosamad; Adib, Ali

    2016-11-01

    Urethrocutaneous fistula (UCF) is the most prevalent complication after hypospadias repair surgery. Many methods have been developed for UCF correction, and the best technique for UCF repair is determined based on the size, location, and number of fistulas, as well as the status of the surrounding skin. In this study, we introduced and evaluated a simple method for UCF correction after tubularized incised plate (TIP) repair. This clinical study was conducted on children with UCFs ≤ 4 mm that developed after TIP surgery for hypospadias repair. The skin was incised around the fistula and the tract was released from the surrounding tissues and the dartos fascia, then ligated with 5 - 0 polydioxanone (PDS) sutures. The dartos fascia, as the second layer, was covered on the fistula tract with PDS thread (gauge 5 - 0) by the continuous suture method. The skin was closed with 6 - 0 Vicryl sutures. After six months of follow-up, surgical outcomes were evaluated based on fistula relapse and other complications. After six months, relapse occurred in only one patient, a six-year-old boy with a single 4-mm distal opening, who had undergone no previous fistula repairs. Therefore, in 97.5% of the cases, relapse was non-existent. Other complications, such as urethral stenosis, intraurethral obstruction, and epidermal inclusion cysts, were not seen in the other patients during the six-month follow-up period. This repair method, which is simple, rapid, and easily learned, is highly applicable, with a high success rate for the closure of UCFs measuring up to 4 mm in any location.

  14. Systematic review and meta-analysis of electrocautery versus scalpel for surgical skin incisions.

    Science.gov (United States)

    Aird, Lisa N F; Brown, Carl J

    2012-08-01

    The creation of surgical skin incisions has historically been performed using a cold scalpel. The use of electrocautery for this purpose has been controversial with respect to patient safety and surgical efficacy. A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to compare skin incisions made by electrocautery and a scalpel. A systematic electronic literature search was performed using 2 electronic databases (MEDLINE and PubMed), and the methodological quality of included publications was evaluated. Six RCTs were identified comparing electrocautery (n = 606) and a scalpel (n = 628) for skin incisions. No significant difference in wound infection rates or scar cosmesis was identified between the treatment groups. Electrocautery significantly reduced the incision time and postoperative wound pain. A trend toward less incisional blood loss from skin incisions made with electrocautery was noted. Electrocautery is a safe and effective method for performing surgical skin incisions. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Dominant mechanisms for the delivery of fine sediment and phosphorus to fluvial networks draining grassland dominated headwater catchments.

    Science.gov (United States)

    Perks, M T; Owen, G J; Benskin, C McW H; Jonczyk, J; Deasy, C; Burke, S; Reaney, S M; Haygarth, P M

    2015-08-01

    Recent advances in monitoring technology have enabled high frequency, in-situ measurements of total phosphorus and total reactive phosphorus to be undertaken with high precision, whilst turbidity can provide an excellent surrogate for suspended sediment. Despite these measurements being fundamental to understanding the mechanisms and flow paths that deliver these constituents to river networks, there is a paucity of such data for headwater agricultural catchments. The aim of this paper is to deduce the dominant mechanisms for the delivery of fine sediment and phosphorus to an upland river network in the UK through characterisation of the temporal variability of hydrological fluxes, and associated soluble and particulate concentrations for the period spanning March 2012-February 2013. An assessment of the factors producing constituent hysteresis is undertaken following factor analysis (FA) on a suite of measured environmental variables representing the fluvial and wider catchment conditions prior to, and during catchment-wide hydrological events. Analysis indicates that suspended sediment is delivered to the fluvial system predominantly via rapidly responding pathways driven by event hydrology. However, evidence of complex, figure-of-eight hysteresis is observed following periods of hydrological quiescence, highlighting the importance of preparatory processes. Sediment delivery via a slow moving, probably sub-surface pathway does occur, albeit infrequently and during low magnitude events at the catchment outlet. Phosphorus is revealed to have a distinct hysteretic response to that of suspended sediment, with sub-surface pathways dominating. However, high magnitude events were observed to exhibit threshold-like behaviour, whereby activation and connection of usually disconnected depositional zones to the fluvial networks results in the movement of vast phosphorus fluxes. Multiple pathways are observed for particulate and soluble constituents, highlighting the

  16. Riparian shrub metal concentrations and growth in amended fluvial mine tailings

    Science.gov (United States)

    Fluvial mine tailing deposition has caused extensive riparian damage throughout the western United States. Willows are often used for fluvial mine tailing revegetation, but some species accumulate excessive metal concentrations which could be detrimental to browsers. In a greenhouse experiment, gr...

  17. The influence of fluvial reservoir architecture on geothermal energy production in Hot Sedimentary Aquifers

    NARCIS (Netherlands)

    Willems, C.J.L.

    2014-01-01

    Currently six geothermal doublets are realized in the WNB. Five of these doublets target the same Lower Cretaceous fluvial sandstone interval, the Nieuwerkerk Formation. About 40 exploration licences are granted. Many of them also have sandstones in the same fluvial interval, the Nieuwerkerk

  18. Modeling plan-form deltaic response to changes in fluvial sediment supply

    NARCIS (Netherlands)

    Nienhuis, J.H.; Ashton, A.D.; Roos, Pieter C.; Hulscher, Suzanne J.M.H.; Giosan, L.; Kranenburg, W.M.; Horstman, E.M.; Wijnberg, K.M.

    2012-01-01

    This study focuses on the effects of changes in fluvial sediment supply on the plan-form shape of wave-dominated deltas. We apply a one-line numerical shoreline model to calculate shoreline evolution after (I) elimination and (II) time-periodic variation of fluvial input. Model results suggest four

  19. The Gediz River fluvial archive : A benchmark for Quaternary research in Western Anatolia

    NARCIS (Netherlands)

    Maddy, D.; Veldkamp, A.; Demir, T.; van Gorp, W.; Wijbrans, J.R.; van Hinsbergen, D.J.J.; Dekkers, M.J.; Schreve, D.; Schoorl, J.M.; Scaife, R.; Stemerdink, C.; van der Schriek, T.; Bridgland, D.R.; Aytaç, A.S.

    2017-01-01

    The Gediz River, one of the principal rivers of Western Anatolia, has an extensive Pleistocene fluvial archive that potentially offers a unique window into fluvial system behaviour on the western margins of Asia during the Quaternary. In this paper we review our work on the Quaternary Gediz River

  20. Implications from Sedimentary records in Fluvial Terraces for Geomorphological Evolution in the Puli Basin, Taiwan

    NARCIS (Netherlands)

    Tseng, C.H.; Wenske, D.; Böse, M.; Reimann, T.; Lüthgens, C.; Frechen, Manfred

    2013-01-01

    Fluvial terraces play an important role for research on previous geomorphic processes as their sediments can record various sedimentation stages. In the mountains of central Taiwan, however, the formation time of sediments in the Puli Basin is still unclear. In this study, we investigate the fluvial

  1. Single incision laparoscopic liver resection (SILL – a systematic review

    Directory of Open Access Journals (Sweden)

    Benzing, Christian

    2015-12-01

    Full Text Available Background: Today, minimally invasive liver resections for both benign and malignant tumors are routinely performed. Recently, some authors have described single incision laparoscopic liver resection (SILL procedures. Since SILL is a relatively young branch of laparoscopy, we performed a systematic review of the current literature to collect data on feasibility, perioperative results and oncological outcome.Methods: A literature research was performed on Medline for all studies that met the eligibility criteria. Titles and abstracts were screened by two authors independently. A study was included for review if consensus was obtained by discussion between the authors on the basis of predefined inclusion criteria. A thorough quality assessment of all included studies was performed. Data were analyzed and tabulated according to predefined outcome measures. Synthesis of the results was achieved by narrative review. Results: A total of 15 eligible studies were identified among which there was one prospective cohort study and one randomized controlled trial comparing SILL to multi incision laparoscopic liver resection (MILL. The rest were retrospective case series with a maximum of 24 patients. All studies demonstrated convincing results with regards to feasibility, morbidity and mortality. The rate of wound complications and incisional hernia was low. The cosmetic results were good.Conclusions: This is the first systematic review on SILL including prospective trials. The results of the existing studies reporting on SILL are favorable. However, a large body of scientific evidence on the field of SILL is missing, further randomized controlled studies are urgently needed.

  2. Magnetic resonance imaging evaluation of incision healing after cesarean sections

    Energy Technology Data Exchange (ETDEWEB)

    Dicle, O. [Department of Radiodiagnosis, Dokuz Eyluel University, Izmir (Turkey); Kuecuekler, C. [Department of Radiodiagnosis, Dokuz Eyluel University, Izmir (Turkey); Pirnar, T. [Department of Radiodiagnosis, Dokuz Eyluel University, Izmir (Turkey); Erata, Y. [Department of Gynecology and Obstetrics, Dokuz Eyluel University, Izmir (Turkey); Posaci, C. [Department of Gynecology and Obstetrics, Dokuz Eyluel University, Izmir (Turkey)

    1997-02-01

    The purpose of this study was to examine the healing period of incision scar in myometrial wall and the normal pelvis after cesarean sections by means of MRI. In this study 17 voluntary women were examined after their first delivery with cesarean section in the early postpartum period (first 5 days), and following this, three more times in 3-month intervals. The MRI examinations were performed on a 1.0-T system (Magnetom, Siemens, Erlangen, Germany), and sagittal T1-weighted (550/17 TR/TE) and T2-weighted (2000/80 TR/TE) spin-echo (SE) images of the pelvis were obtained. During follow-up examinations incision scar tissues lost their signals within the first 3 months on both SE sequences, and little alteration was observed in the subsequent tests. Zonal anatomy of the uterus reappeared completely 6 months after cesarean sections. The time for the involution of the uterus was independent of the zonal anatomy recovery, and the maximum involution was inspected within the first 3 months. In conclusion, the maturation time of myometrial scar tissue in uncomplicated cesarean sections, which can be evaluated by the signal alterations in MRI, is approximately 3 months, whereas the complete involution and the recovery of the zonal anatomy need at least 6 months. (orig.). With 6 figs.

  3. Muscle sparing lateral thoracotomy: the standard incision for thoracic procedures

    Directory of Open Access Journals (Sweden)

    Mihai Dumitrescu

    2017-05-01

    Full Text Available Lateral thoracotomy is a versatile approach with many variations and is currently the most widely used incision in thoracic surgery. In the current article we are presenting the muscle-sparing lateral thoracotomy in the lateral decubitus position which we consider to be the “standard” for lateral thoracotomies. Indications, surgical technique and pitfalls are described alongside our experience with thoracic drainage. Although there is no consensus regarding the name of this incision, some authors call it “axillary thoracotomy” while others call it a “modified lateral thoracotomy”, they all agree on one aspect – the importance of muscle sparing – which makes it the go-to thoracotomy for both small and large procedures involving the lung. Lateral muscle sparing thoracotomy allows for good exposure of the pulmonary hilum, fissures, apex and diaphragm. The approach is easy and quick to perform while at the same time ensuring faster postoperative recovery by sparing the latissimus dorsi muscle, better cosmetics and lower postoperative pain score when compared to the posterolateral or classical lateral thoracotomies.

  4. Magnetic resonance imaging evaluation of incision healing after cesarean sections

    International Nuclear Information System (INIS)

    Dicle, O.; Kuecuekler, C.; Pirnar, T.; Erata, Y.; Posaci, C.

    1997-01-01

    The purpose of this study was to examine the healing period of incision scar in myometrial wall and the normal pelvis after cesarean sections by means of MRI. In this study 17 voluntary women were examined after their first delivery with cesarean section in the early postpartum period (first 5 days), and following this, three more times in 3-month intervals. The MRI examinations were performed on a 1.0-T system (Magnetom, Siemens, Erlangen, Germany), and sagittal T1-weighted (550/17 TR/TE) and T2-weighted (2000/80 TR/TE) spin-echo (SE) images of the pelvis were obtained. During follow-up examinations incision scar tissues lost their signals within the first 3 months on both SE sequences, and little alteration was observed in the subsequent tests. Zonal anatomy of the uterus reappeared completely 6 months after cesarean sections. The time for the involution of the uterus was independent of the zonal anatomy recovery, and the maximum involution was inspected within the first 3 months. In conclusion, the maturation time of myometrial scar tissue in uncomplicated cesarean sections, which can be evaluated by the signal alterations in MRI, is approximately 3 months, whereas the complete involution and the recovery of the zonal anatomy need at least 6 months. (orig.). With 6 figs

  5. Discussion on the Relevant Factors of General Surgery Incision Infection and Prevention Methods

    Directory of Open Access Journals (Sweden)

    Jin Baotao

    2017-01-01

    Full Text Available There are many reasons that can lead to incision infection of general surgical patients. The main reasons include weight, age, body albumin level, surgical time, observation ward, etc. This paper analyzes the clinic data of patients with incision infection after general surgery based on clinic practice and study on the reasons that have impact on general surgical incision infection and gives relevant prevention countermeasures.

  6. Coastal knickpoints and the competition between fluvial and wave-driven erosion on rocky coastlines

    Science.gov (United States)

    Limber, Patrick; Barnard, Patrick

    2018-01-01

    Active margin coastlines are distinguished by rock erosion that acts in two different directions: waves erode the coast horizontally or landwards, a process that creates sea cliffs; and rivers and streams erode the landscape vertically via channel incision. The relative rates of each process exert a dominant control on coastline morphology. Using a model of river channel incision and sea-cliff retreat, we explore how terrestrial and marine erosion compete to shape coastal topography, and specifically what conditions encourage the development of coastal knickpoints (i.e., a river or stream channels that end at a raised sea-cliff edge). We then compare results to actual landscapes. Model results and observations show that coastal knickpoint development is strongly dependent on drainage basin area, where knickpoints typically occur in drainage basins smaller than 5 × 105–6 × 106 m2, as well as channel geometry and sea-cliff retreat rate. In our study area, coastal knickpoints with persistent flow (waterfalls) are uncommon and form only within a small morphological window when 1) drainage basin area is large enough to sustain steady stream discharge, but not large enough to out-compete sea-cliff formation, 2) sea-cliff retreat is rapid, and 3) channel concavity is low so that channel slopes at the coast are high. This particular geomorphic combination can sustain sea-cliff formation even when streams tap into larger drainage basins with greater discharge and more stream power, and provides an initial explanation of why persistent coastal waterfalls are, along many coastlines, relatively rare features.

  7. Coastal knickpoints and the competition between fluvial and wave-driven erosion on rocky coastlines

    Science.gov (United States)

    Limber, Patrick W.; Barnard, Patrick L.

    2018-04-01

    Active margin coastlines are distinguished by rock erosion that acts in two different directions: waves erode the coast horizontally or landwards, a process that creates sea cliffs; and rivers and streams erode the landscape vertically via channel incision. The relative rates of each process exert a dominant control on coastline morphology. Using a model of river channel incision and sea-cliff retreat, we explore how terrestrial and marine erosion compete to shape coastal topography, and specifically what conditions encourage the development of coastal knickpoints (i.e., a river or stream channels that end at a raised sea-cliff edge). We then compare results to actual landscapes. Model results and observations show that coastal knickpoint development is strongly dependent on drainage basin area, where knickpoints typically occur in drainage basins smaller than 5 × 105-6 × 106 m2, as well as channel geometry and sea-cliff retreat rate. In our study area, coastal knickpoints with persistent flow (waterfalls) are uncommon and form only within a small morphological window when 1) drainage basin area is large enough to sustain steady stream discharge, but not large enough to out-compete sea-cliff formation, 2) sea-cliff retreat is rapid, and 3) channel concavity is low so that channel slopes at the coast are high. This particular geomorphic combination can sustain sea-cliff formation even when streams tap into larger drainage basins with greater discharge and more stream power, and provides an initial explanation of why persistent coastal waterfalls are, along many coastlines, relatively rare features.

  8. Stability of Fluvial and Gravity-flow Antidunes

    Science.gov (United States)

    Fedele, J. J.; Hoyal, D. C. J. D.; Demko, T. M.

    2017-12-01

    Antidunes develop as a consequence of interface (free surface) deformation and sediment transport feedback in supercritical flows. Fluvial (open-channel flow) antidunes have been studied extensively in the laboratory and the field, and recognized in ancient sedimentary deposits. Experiments on gravity flow (turbidity and density currents) antidunes indicate that they are more stable and long-lived than their fluvial counterpart but the mechanism controlling this stability is poorly understood. Sea floor bathymetric and subsurface data suggest that large-scale, antidune-like sediment waves are extremely common in deep-water, found in a wide range of settings and sediment characteristics. While most of these large features have been interpreted as cyclic steps, the term has been most likely overused due to the lack of recognition criteria and basic understanding on the differences between antidunes and cyclic steps formed under gravity flows. In principle, cyclic steps should be more common in confined or channel-lobe transition settings where flows tend to be more energetic or focused, while antidunes should prevail in regions of less confinement, under sheet-like or expanding flows. Using published, fluvial stable-antidune data, we show that the simplified 1D, mechanical-energy based analysis of flow over a localized fixed obstacle (Long, 1954; Baines, 1995; Kubo and Yokokawa, 2001) is inaccurate for representing flow over antidunes and their stability. Instead, a more detailed analysis of a flow along a long-wavelength (in relation to flow thickness) wavy bed that also considers the interactions between flow and sediment transport is used to infer conditions of antidune stability and the breaking of surface waves. In particular, the position of the surface wave crest in relation to the bedform crest, along with the role of average flow velocity, surface velocity, and surface wave celerity appear relevant in determining antidune instability. The analysis is

  9. SISTEMA FLUVIAL E PLANEJAMENTO LOCAL NO SEMIÁRIDO

    Directory of Open Access Journals (Sweden)

    Jonas Otaviano Praça de Souza

    2012-01-01

    Full Text Available El presente estudio analiza un sistema fluvial semiárido y sus características físicas, centrándose en los procesos geomorfológicos y las formas resultantes, sino también en las relaciones con las actividades humanas, con el fin de utilizar dichos datos en la planificación local. La encuesta se llevó a cabo en el municipio de Belém do São Francisco, en Pernambuco, mesorregión del São Francisco en la cuenca del arroyo Mulungu, lugar expuesto a un clima semi-árido con lluvias de verano, y la cobertura del suelo con un predominio de la caatinga arbustiva abierta. Se tomó como procedimiento metodológico la cartografía geomorfológica a diferentes escalas y con diferentes énfasis, para evaluar la relación jerárquica entre los distintos compartimentos, sustratos geológicos y formas de uso de la tierra. De la información espacial obtenida en los distintos niveles de la cartografía detallada del sistema fluvial, se realizó una evaluación ambiental de la zona, teniendo como base la dinámica erosiva/deposicional a lo largo del canal y su relación con sus bancos. Se concluyó que las formas de acumulación en la llanura aluvial exhiben controles de origen antropogénico, vinculados a los tipos tradicionales de uso del suelo en la cuenca. Estos controles, como la construcción de represas a lo largo del canal, actúan cambiando a los procesos de creación de nuevas morfologías de depósito en el sistema fluvial, que a su vez comienzan a redefinir los tipos usos de la zona.

  10. Long-Term Incisal Relationships After Palatoplasty in Patients With Isolated Cleft Palate.

    Science.gov (United States)

    Odom, Elizabeth B; Woo, Albert S; Mendonca, Derick A; Huebener, Donald V; Nissen, Richard J; Skolnick, Gary B; Patel, Kamlesh B

    2016-06-01

    Various palatoplasty techniques have limited incisions in the hard palate due to concerns that these incisions may limit maxillary growth. There is little convincing long-term evidence to support this. Our purpose is to determine incisal relationships, an indicator for future orthognathic procedure, in patients after repair of an isolated cleft of the secondary palate. Our craniofacial database was used to identify patients aged 10 years or greater with an isolated cleft of the secondary palate who underwent palatoplasty between 1985 and 2002. Data collected included age at palatoplasty and follow-up, cleft type, associated syndrome, Robin sequence, surgeon, repair technique, number of operations, and occlusion. Incisal relationship was determined through clinical observation by a pediatric dentist and orthodontist. Seventy eligible patients operated on by 9 surgeons were identified. Class III incisal relationship was seen in 5 patients (7.1%). Palatoplasty techniques over the hard palate (63 of 70 patients) included 2-flap palatoplasty, VY-pushback, and Von Langenbeck repair. There was an association between class III incisal relationship and syndromic diagnosis (P <0.001). Other study variables were not associated with class III incisal relationships. In patients with an isolated cleft of the secondary palate, there was no association between class III incisal relationship and surgeon, age at repair, cleft type, palatoplasty technique, or number of operations. Increased likelihood of class III incisal relationship was associated primarily with syndromic diagnosis.

  11. Midline versus transverse incision for cesarean delivery in low-income countries

    DEFF Research Database (Denmark)

    Maaløe, Nanna; Aabakke, Anna J M; Secher, Niels J

    2014-01-01

    While transverse incision is the recommended entry technique for cesarean delivery in high-income countries, it is our experience that midline incision is still used routinely in many low-income settings. Accordingly, international guidelines lack uniformity on this matter. Although evidence...... is limited, the literature suggests important advantages of the transverse incision, with lower risk of long-term disabilities such as wound disruption and hernia. Also, potential extra time spent on this incision appears not to impact neonatal outcome. Therefore, we suggest that it is time for a change...

  12. Diathermy vs. scalpel skin incisions in general surgery: double-blind, randomized, clinical trial.

    Science.gov (United States)

    Shamim, Muhammad

    2009-08-01

    This prospective, double-blind, randomized, controlled trial was designed to compare the outcome of diathermy incisions versus scalpel incisions in general surgery. A total of 369 patients who underwent diathermy incision (group A: 185 patients) or scalpel incision (group B: 184 patients) were analyzed. Variables analyzed were: surgical wound classification, length and depth of incision, incision time, duration of operation, incisional blood loss, postoperative pain, duration of hospital stay, duration of healing, and postoperative complications. The inclusion criteria were all patients who underwent elective or emergency general surgery. The exclusion criteria were only cases with incomplete patients' data and patients who were lost to follow-up. This study was conducted at Fatima Hospital-Baqai Medical University and Shamsi Hospital (Karachi), from January 2006 to December 2007. Incision time was significantly longer for patients in group B (p = 0.001). Incisional blood loss also was more for patients in group B (p = 0.000). Pain perception was found to be markedly reduced during the first 48 h in group A (p = 0.000). Total period of hospital stay (p = 0.129) and time for complete wound healing (p = 0.683) were almost the same for both groups. Postoperative complication rate by wound classification did not differ markedly between the two groups (p = 0.002 vs. p = 0.000). Diathermy incision has significant advantages compared with the scalpel because of reduced incision time, less blood loss, & reduced early postoperative pain.

  13. Advantages of the modified double ring areolar incision over the traditional areolar incision in multicentric breast fibroadenoma surgery.

    Science.gov (United States)

    Zhang, Mingliang; Shen, Gongjin; Zhang, Song; Cui, Zhen; Qian, Jun

    2017-09-01

    This study was conducted to investigate the clinical advantages of modified double ring areola incision (MDRAI) compared to ordinary areola incision (OAI) in multicentric breast fibroadenoma in women. Sixty cases of multicentric benign breast tumor were recruited from the First Affiliated Hospital of Bengbu Medical College from January to December 2016. The cases were divided into two groups according to surgical approach: MDRAI (n = 20) and OAI (n = 40). The operation duration, intraoperative blood loss, drainage time, and postoperative recurrence rate in the first six months were compared. The mean age and tumor locations were not statistically different between the groups (P > 0.05). However, more lesions and larger tumor diameter were found in the MDRAI group than in the OAI group, with statistical difference (P  0.05). However, the intraoperative blood loss was statistically different between the two groups (P < 0.05). All 60 cases received six months of follow-up. Eight recurrent cases were found in the OAI group, but none in the MDRAI group. The recurrence rate was significantly different (χ 2  = 4.62, P < 0.05). Compared with OAI, MDRAI offers greater advantages in the aspects of blood loss and recurrence for the treatment of breast benign tumor, especially for multicentric larger lesions. © 2017 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

  14. Fluvial responses to land-use changes and climatic variations within the Drury Creek watershed, southern Illinois

    Science.gov (United States)

    Miller, Suzanne Orbock; Ritter, Dale F.; Kochel, R. Craig; Miller, Jerry R.

    1993-04-01

    Fluvial responses to climatic variation and Anglo-American settlement were documented for the Drury Creek watershed, southern Illinois by examining stratigraphic, geomorphic, climatic, and historical data. Regional analyses of long-term precipitation records document a period of decreasing mean annual precipitation from 1904 to about 1945, and an increasing trend in annual precipitation from 1952 to the present. The period between 1945 and 1951 experienced a large number of intense storms that resulted in high annual precipitation totals. Statistical relationships illustrate that changes in precipitation totals are transferred to the hydrologic system as fluctuations in stream discharge. Historical records of southern Illinois show that a maximum period of settlement and deforestation occurred between the 1860s and 1920s. This era ended in the 1940s when large tracts of land were revegetated in an attempt to curtail erosion which had caused extensive upland degradation. In response to hillslope erosion at least two meters of fine-grained sediments were deposited on valley floors. Average sedimentation rates, determined using decdrochronologic techniques, are estimated to be 2.11 cm/yr for the period between 1890 and 1988; rates that are 1 to 2 orders of magnitude greater than pre-settlement values calculated for other areas of the midwest. However, botanical data suggest that aggradation was episodic, possibly occurring during three periods characterized by greater annual precipitation. Since the 1940s, sedimentation rates have declined. Reduced rates of sedimentation are related to an episode of channel entrenchment that reduced overbank flooding. Entrenchment coincided with a period of: (1) reduced sediment yields associated with watershed revegetation and the introduction of soil conservation practices, and (2) intense storm activity that resulted in long periods of high discharge. As a result of channel incision and hillslope erosion, newly exposed bedrock in

  15. Arsenic and fluvial biofilms: biogeochemistry, toxicity and biotic interactions

    OpenAIRE

    Barral Fraga, Laura

    2017-01-01

    Basándonos en los conocimientos actuales sobre la ecotoxicología del biofilm y la biogeoquímica del arsénico en ecosistemas dulceacuícolas, esta tesis estudió, bajo concentraciones ambientales realistas, i) el papel de los biofilms bentónicos en la biodisponibilidad y destoxificación del arsénico, ii) los efectos tóxicos del arsénico sobre la estructura y función de los biofilms bentónicos fluviales, prestando especial atención a las respuestas de las diatomeas, y iii) la interacción entre es...

  16. Fluvial sediment transport: Analytical techniques for measuring sediment load

    International Nuclear Information System (INIS)

    2005-07-01

    Sediment transport data are often used for the evaluation of land surface erosion, reservoir sedimentation, ecological habitat quality and coastal sediment budgets. Sediment transport by rivers is usually considered to occur in two major ways: (1) in the flow as a suspended load and (2) along the bed as a bed load. This publication provides guidance on selected techniques for the measurement of particles moving in both modes in the fluvial environment. The relative importance of the transport mode is variable and depends on the hydraulic and sedimentary conditions. The potential user is directed in the selection of an appropriate technique through the presentation of operating principles, application guidelines and estimated costs. Techniques which require laboratory analysis are grab sample, pump sample, depth sample, point integrated and radioactive tracers. Techniques which will continuously record data are optical backscattering, nuclear transmission, single frequency acoustic and laser diffraction

  17. Outcomes of small incision lenticule extraction (SMILE) in low myopia.

    Science.gov (United States)

    Reinstein, Dan Z; Carp, Glenn I; Archer, Timothy J; Gobbe, Marine

    2014-12-01

    To report the visual and refractive outcomes of small incision lenticule extraction for low myopia using the VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany). A retrospective analysis of 120 consecutive small incision lenticule extraction procedures was performed for low myopia. Inclusion criteria were preoperative spherical equivalent refraction up to -3.50 diopters (D), cylinder up to 1.50 D, and corrected distance visual acuity of 20/20 or better. Outcomes analysis was performed for all eyes with 1-year follow-up according to the Standard Graphs for Reporting Refractive Surgery, and also including mesopic contrast sensitivity. One-year data were available for 110 eyes (92%). Preoperatively, mean spherical equivalent refraction was -2.61 ± 0.54 D (range: -1.03 to -3.50 D) and mean cylinder was 0.55 ± 0.38 D (range: 0.00 to 1.50 D). Postoperatively, mean spherical equivalent refraction was -0.05 ± 0.36 D (range: -0.94 to +1.25 D) and mean cylinder was ± 0.50 D in 84% and ± 1.00 D in 99% of eyes. Uncorrected distance visual acuity was 20/20 or better in 96% of eyes and 20/25 or better in 100% of eyes. One line of corrected distance visual acuity was lost in 9%, but no eyes lost two or more lines. There was an initial overcorrection in mean spherical equivalent refraction on day 1 (+0.37 D) as expected, which regressed to +0.10 D at 1 month and -0.05 D at 3 months, after which stability was reached (mean spherical equivalent refraction was -0.05 D at 1 year). Contrast sensitivity at 1 year was slightly increased at 3, 6, 12, and 18 cycles per degree (P < .05). Small incision lenticule extraction for low myopia was found to be safe and effective with outcomes similar to those previously reported for LASIK. Copyright 2014, SLACK Incorporated.

  18. Formation of topographically inverted fluvial deposits on Earth and Mars

    Science.gov (United States)

    Hayden, A.; Lamb, M. P.; Fischer, W. W.; Ewing, R. C.; McElroy, B. J.

    2016-12-01

    Sinuous ridges interpreted as exhumed river deposits (so-called "inverted channels") are common features on Mars that show promise for quantifying ancient martian surface hydrology. Morphological similarity of these inverted channels to river channels led to a "landscape inversion hypothesis" in which the geometries of ridges and ridge networks accurately reflect the geometries of the paleo-river channels and networks. An alternative "deposit inversion hypothesis" proposes that ridges represent eroded fluvial channel-belt deposits with channel-body geometries that may differ significantly from those of the rivers that built the deposit. To investigate these hypotheses we studied the sedimentology and morphology of inverted channels in Jurassic and Cretaceous outcrops in Utah and the Aeolis Dorsa region of Mars. Ridges in Utah extend for hundreds of meters, are tens of meters wide, and stand up to 30 meters above the surrounding plain. A thick ribbon-geometry sandstone or conglomerate body caps overbank mudstone, paleosols, and thin crevasse-splay sandstone beds. Caprock beds consist of stacked dune- to bar-scale trough cross sets, mud intraclasts, and in cases scroll bars indicating meandering. In plan view, ridge networks bifurcate; however, crosscutting relationships show that distinct sandstone channel bodies at distinct stratigraphic levels intersect at these junctions. Ridge-forming sandstone bodies have been narrowed from their original dimensions by cliff retreat and bisected by modern fluvial erosion and mass wasting. We therefore interpret the sinuous ridges in Utah as eroded remnants of channel-belt sandstone bodies formed by laterally migrating and avulsing rivers rather than channel fills - consistent with deposit inversion. If the sinuous ridges in Aeolis Dorsa also formed by deposit inversion, river widths previously interpreted under the landscape inversion hypothesis are overestimated by up to a factor of 10 and discharges by up to a factor of 100.

  19. Estuarine abandoned channel sedimentation rates record peak fluvial discharge magnitudes

    Science.gov (United States)

    Gray, A. B.; Pasternack, G. B.; Watson, E. B.

    2018-04-01

    Fluvial sediment deposits can provide useful records of integrated watershed expressions including flood event magnitudes. However, floodplain and estuarine sediment deposits evolve through the interaction of watershed/marine sediment supply and transport characteristics with the local depositional environment. Thus extraction of watershed scale signals depends upon accounting for local scale effects on sediment deposition rates and character. This study presents an examination of the balance of fluvial sediment dynamics and local scale hydro-geomorphic controls on alluviation of an abandoned channel in the Salinas River Lagoon, CA. A set of three sediment cores contained discrete flood deposits that corresponded to the largest flood events over the period of accretion from 1969 to 2007. Sedimentation rates scaled with peak flood discharge and event scale sediment flux, but were not influenced by longer scale hydro-meteorological activities such as annual precipitation and water yield. Furthermore, the particle size distributions of flood deposits showed no relationship to event magnitudes. Both the responsiveness of sedimentation and unresponsiveness of particle size distributions to hydro-sedimentological event magnitudes appear to be controlled by aspects of local geomorphology that influence the connectivity of the abandoned channel to the Salinas River mainstem. Well-developed upstream plug bar formation precluded the entrainment of coarser bedload into the abandoned channel, while Salinas River mouth conditions (open/closed) in conjunction with tidal and storm surge conditions may play a role in influencing the delivery of coarser suspended load fractions. Channel adjacent sediment deposition can be valuable records of hydro-meteorological and sedimentological regimes, but local depositional settings may dominate the character of short term (interdecadal) signatures.

  20. Architectural elements and bounding surfaces in fluvial deposits: anatomy of the Kayenta formation (lower jurassic), Southwest Colorado

    Science.gov (United States)

    Miall, Andrew D.

    1988-03-01

    Three well-exposed outcrops in the Kayenta Formation (Lower Jurassic), near Dove Creek in southwestern Colorado, were studied using lateral profiles, in order to test recent regarding architectural-element analysis and the classification and interpretation of internal bounding surfaces. Examination of bounding surfaces within and between elements in the Kayenta outcrops raises problems in applying the three-fold classification of Allen (1983). Enlarging this classification to a six-fold hierarchy permits the discrimination of surfaces intermediate between Allen's second- and third-order types, corresponding to the upper bounding surfaces of macroforms, and internal erosional "reactivation" surfaces within the macroforms. Examples of the first five types of surface occur in the Kayenta outcrops at Dove Creek. The new classifications is offered as a general solution to the problem of description of complex, three-dimensional fluvial sandstone bodies. The Kayenta Formation at Dove Creek consists of a multistorey sandstone body, including the deposits of lateral- and downstream-accreted macroforms. The storeys show no internal cyclicity, neither within individual elements nor through the overall vertical thickness of the formation. Low paleocurrent variance indicates low sinuosity flow, whereas macroform geometry and orientation suggest low to moderate sinuosity. The many internal minor erosion surfaces draped with mud and followed by intraclast breccias imply frequent rapid stage fluctuation, consistent with variable (seasonal? monsonal? ephemmeral?) flow. The results suggest a fluvial architecture similar to that of the South Saskatchewan River, through with a three-dimensional geometry unlike that interpreted from surface studies of that river.

  1. Mouse preferential incising force orientation changes during jaw closing muscle hyperalgesia and is sex dependent.

    Science.gov (United States)

    Widmer, C G; Morris-Wiman, J

    2016-12-01

    Mouse incising is controlled by a central pattern generator and this activity can change in the presence of pain. The incising frequency and maximum force generation decreases with pain. In this study, we used repetitive acidic injections in the left masseter muscle of male and female mice to determine differences between baseline and jaw muscle pain conditions and the effect of sex on preferential incising direction. A within subject design was used to evaluate data previously acquired using multi-axis force data (X, Y and Z) from the 4th baseline recording day and day 7 post-injection (day of maximal pain response) for each mouse of each sex. A total of 34 female and male (age 3-9months) CD-1 mice were evaluated. After mathematically rotating the X and Y axes to align the Y axis to be parallel to the wire struts of the cage top, data were analyzed to determine incising direction preference during baseline (non-pain) and pain (day 7) conditions and between sex. Radar plots of X-Y, X-Z and Y-Z axes depicted the average direction of incising preference between baseline and pain conditions for each sex. Statistical differences among groups were tested using a mixed model ANOVA. Similar to previous findings, female mice had a more robust difference in incising direction preference when comparing male and female pain conditions and this was most evident in the X-Z axes. The incising frequencies most commonly affected were 5.3, 6.2 and 7.6Hz. Male mice varied little in their incising direction preference between the baseline and pain conditions. In addition, statistical comparison of ratios of the percent of time spent incising in the Z versus X axes for each incising frequency found that the incising preference was not different when comparing 5.3 and 7.6Hz frequencies. Finally, female mice used a novel approach to minimize pain while incising by rotating their head and body nearly 180 degrees while males did not use this strategy as frequently. The preferred incising

  2. Clear corneal incision leakage after phacoemulsification--detection using povidone iodine 5%.

    Science.gov (United States)

    Chee, Soon-Phaik

    2005-01-01

    The purpose of this work was to study the incidence of clear corneal wound leakage at the conclusion of standard co-axial phacoemulsification in a prospective observational series of 100 consecutive cataract cases in a single surgeon's institutional practice. At the conclusion of standard co-axial phacoemulsification using a 2.75 mm temporal single plane clear corneal incision with a 1 mm clear corneal side-port incision, the wounds were hydrated and checked for water-tightness. Povidone iodine 5% (P-I) was then evenly dripped over the cornea and the wounds were inspected visually. Any leakage of aqueous observed was recorded. The amount of leakage was graded as small or large from each wound. Leaky wounds were further hydrated and retested with P-I until sealed. Wound integrity was reassessed on the first postoperative day by use of fluorescein. Of the 100 cases, wound leakage was observed for 31 eyes (31%)-ten main incisions, nineteen side-port incisions, and both incisions in two cases. Wound leakage was easily detected as a ribbon of clear fluid streaming from the incision amid a pool of brown solution. Povidone iodine was not observed within the tract in any incision. All wound leakage was small except for one from the main incision and two from the side-port incision. None of the eyes developed wound leakage the day after surgery and none developed endophthalmitis. In conclusion, leakage from clear corneal incisions at the conclusion of phacoemulsification occurs in almost a third of cases, predominantly from the side incision. It is easily detected by use of the P-I test.

  3. Effects of post-treatment incubation on recombinogenesis in incision-proficient and incision-deficient strains of saccharomyces cerevisiae, 2

    International Nuclear Information System (INIS)

    Saeki, Tetsuya; Machida, Isamu

    1991-01-01

    After the photoaddition of mono- and bifunctional furocoumarins to G1 phase cells, most gene conversion and crossing-over occurred without post-irradiation incubation of these cells in incision-proficient strains. In contrast, incision-deficient cells showed marked induction of both recombinational events only after treated cells had been incubated for several hours before selection. These results indicate that when furocoumarins are photoadded to G1 cells, initiation of recombinational events occurs during the same G1 phase in the incision-proficient cells; whereas, it occurs only after post-irradiation DNA replication in incision-deficient cells. The action of the PSO2 gene product specific for the repair of DNA crosslinks in recombination induction is discussed and compared to the actions of the excision repair genes RAD1 and RAD2. (author)

  4. Median sternotomy - gold standard incision for cardiac surgeons

    Directory of Open Access Journals (Sweden)

    Radu Matache

    2016-05-01

    Full Text Available Sternotomy is the gold standard incision for cardiac surgeons but it is also used in thoracic surgery especially for mediastinal, tracheal and main stem bronchus surgery. The surgical technique is well established and identification of the correct anatomic landmarks, midline tissue preparation, osteotomy and bleeding control are important steps of the procedure. Correct sternal closure is vital for avoiding short- and long-term morbidity and mortality. The two sternal halves have to be well approximated to facilitate healing of the bone and to avoid instability, which is a risk factor for wound infection. New suture materials and techniques would be expected to be developed to further improve the patients evolution, in respect to both immediate postoperative period and long-term morbidity and mortality

  5. Mandibular incisive canal in relation to periapical surgery

    Directory of Open Access Journals (Sweden)

    Kani Bilginaylar

    2016-01-01

    Full Text Available The aim of the present paper is to emphasize the importance of the mandibular interforaminal neurovascular bundle with a case and make a warning to dentists and surgeons during oral and maxillofacial surgeries, such as implant replacement, bone harvesting, genioplasty, open reduction of a mandibular fracture, and cyst enucleations at this region. In this paper, we present a 58-year-old male who referred with pain and a tingling sensation on the left lower lip. After radiographical, extraoral and intraoral examinations, findings indicated the lesion to be a cyst which was related with a periapical lesion of the canine tooth and extracted socket of first premolar tooth. After removal of a cyst, the mandibular incisive nerve was documented which was in relation to cyst cavity.

  6. A case of bifocal endometriosis involving a pfannenstiel incision.

    Science.gov (United States)

    Evsen, Mehmet Sidik; Sak, Muhammet Erdal; Yalinkaya, Ahmet; Firat, Ugur; Caca, Fatma Nur

    2011-01-01

    A 25-year-old woman was referred to our clinic for atypical cyclic pain and masses at both ends of a Pfannenstiel incision scar. Ultrasound of the anterior abdominal wall showed two masses. Both masses were hypoechoic, heterogeneous lesions located at opposite ends of the scar. The lesions were surgically excised with. Microscopic examination revealed endometrial gland structures with endometrial stroma in fibroadipose tissue in sections of both specimens indicative of endometriosis. Incisional endometriosis (IE) is a form of extrapelvic endometriosis especially in scars of obstetric or gynecologic surgery IE may be multifocal at surgical scars. We report the a case of bifocal incisional endometriosis in Pfannesteil scar. Whole scar evaluation should be done for incisional endometriosis and surgical excision should be performed for treatment.

  7. Performance of fast-absorbable suture and histo-glue in closing incisions in Brown trout

    DEFF Research Database (Denmark)

    Jepsen, Niels; Larsen, Martin Hage; Aarestrup, Kim

    2017-01-01

    , growth, tag expulsion rate and incision healing was compared among three groups of dummy transmitter-tagged wild brown trout Salmo trutta where incisions were closed with two types of suture material (absorbable vs. fast absorbable) and Histo-glue. The tagged fish were kept in semi-natural ponds for 20...

  8. Landform Evolution Modeling of Specific Fluvially Eroded Physiographic Units on Titan

    Science.gov (United States)

    Moore, J. M.; Howard, A. D.; Schenk, P. M.

    2015-01-01

    Several recent studies have proposed certain terrain types (i.e., physiographic units) on Titan thought to be formed by fluvial processes acting on local uplands of bedrock or in some cases sediment. We have earlier used our landform evolution models to make general comparisons between Titan and other ice world landscapes (principally those of the Galilean satellites) that we have modeled the action of fluvial processes. Here we give examples of specific landscapes that, subsequent to modeled fluvial work acting on the surfaces, produce landscapes which resemble mapped terrain types on Titan.

  9. Thermal study of bare tips with various system parameters and incision sizes.

    Science.gov (United States)

    Osher, Robert H; Injev, Valentine P

    2006-05-01

    To identify major and minor surgeon-controlled parameters that affect incision temperature when performing microincision lens removal using the Alcon Infiniti Vision System. In vitro research and development laboratory, Alcon Research, Irvine, California, USA. Phacoemulsification was performed in eye-bank cadaver eyes and the following parameters evaluated: incision, duty cycle, ultrasound (US) power, aspiration flow rate (AFR), vacuum, pulse, bottle height and balanced salt solution temperature, and tip design/size. Each parameter was varied while the others remained constant. The resulting temperature of the incision and US tip was measured using a thermal camera. Major contributors to elevated incision temperature included incision size, US power, duty cycle, AFR, vacuum setting, tip design, and presence of an ophthalmic viscosurgical device (OVD). Minor contributors included pulse frequency, bottle height, and temperature of the infusate. Microincision lens removal can be performed at safe temperatures with the knowledgeable selection of surgeon-controlled parameters.

  10. Single-incision laparoscopic surgery through an ostomy site: a natural approach by an unnatural orifice.

    Science.gov (United States)

    Lopez, Nicole E; Peterson, Carrie Y; Ramamoorthy, Sonia L; McLemore, Elisabeth C; Sedrak, Michael F; Lowy, Andrew M; Horgan, Santiago; Talamini, Mark A; Sicklick, Jason K

    2015-02-01

    Single-incision laparoscopic surgery (SILS) is gaining popularity for a wide variety of surgical operations and capitalizes on the benefits of traditional laparoscopic surgery without incurring multiple incision sites. Traditionally, SILS is performed by a midline periumbilical approach. However, such a minimally invasive approach may be utilized in patients who already have an abdominal incision. Our series retrospectively reviews 7 cases in which we utilized the fascial defect at the time of after ostomy reversal as our SILS incision site. In turn, we performed a variety of concurrent intra-abdominal procedures with excellent technical success and outcomes. Our study is the largest single-institution case series of this novel approach and suggests that utilizing an existing ostomy-site abdominal incision is a safe and effective location for SILS port placement and should be considered in patients undergoing concurrent procedures.

  11. Downstream mixing of sediment and tracers in agricultural catchments: Evidence of changing sediment sources and fluvial processes?

    Science.gov (United States)

    Ralph, Timothy; Wethered, Adam; Smith, Hugh; Heijnis, Henk

    2014-05-01

    Land clearance, soil tillage and grazing in agricultural catchments have liberated sediment and altered hydrological connectivity between hillslopes and channels, leading to increased sediment availability, mobilisation and delivery to rivers. The type and amount of sediment supplied to rivers is critical for fluvial geomorphology and aquatic ecosystem health. Contemporary sediment dynamics are routinely investigated using environmental radionuclides such as caesium-137 (Cs-137) and excess lead-210 (Pb-210ex), which can provide information regarding sediment source types and fluvial processes if sediment sources can be distinguished from one another and mixing models applied to representative samples. However, downstream transport, mixing and dilution of radionuclide-labelled sediment (especially from sources with low initial concentrations) can obliterate the tracer signal; sometimes before anything of geomorphological importance happens in the catchment. Can these findings be used as evidence of sediment source variations and fluvial processes when the limits of detection (of Cs-137 in particular) are being exceeded so rapidly downstream? Sediment sources and downstream sediment dynamics were investigated in Coolbaggie Creek, a major supplier of sediment to the Macquarie River in an agricultural catchment with temperate to semi-arid climate in Australia. Radionuclides were used to discriminate between the banks and gullies (Cs-137 1.45 +/- 0.47 Bq/kg; Pb-210ex 4.67 +/- 1.93 Bq/kg). Within the trunk stream, suspended sediment, organic matter and Cs-137 and Pb-210ex concentrations declined downstream. Results from a mixing model suggest that agricultural topsoils account for 95% of fine sediment entering the channel in the upper reach (200 m2) downstream, with channel expansion and gullies contributing fine sediment to the system. A lack of topsoil being supplied to the channel suggests minimal lateral connectivity between the catchment and the trunk stream in all

  12. STUDY OF VARIOUS MODALITIES IN MANAGEMENT OF INCISION HERNIA REPAIR

    Directory of Open Access Journals (Sweden)

    Raghu Rachha

    2018-03-01

    Full Text Available BACKGROUND Incisional hernias are a major problem following abdominal surgery and their repairs are among the common surgeries done by a general surgeon.1 Besides the preoperative factors such as anaemia, BMI over 25 kg/m2 and smoking which are leading causes contributing to the development of Incisional hernia, laparotomy performed through the abdominal incision doubles the risk of IH.2 In addition, wound infection, increases the risk of IH formation by 1.9 times.3 If left unattended they may attain large size therefore cause discomfort and lead to the complications like Obstruction, Strangulation, Incarceration increasing the risk of morbidity and mortality.4 Treatment of IH involves further major surgery and the results may be poor, with the recurrence rates of up to 49% reported.5 A wide spectrum of surgical techniques have been developed and recommended ranging from sutured techniques to the various types of prosthetic mesh. MATERIALS AND METHODS 30 patients were studied who presented to emergency department with incisional hernias during August 2014 – September 2016 at Gandhi Medical College and Hospital. All patients underwent definitive treatment. RESULTS From our study it is observed that 1. The maximum cases of incisional hernias presenting to the emergency surgical department were found to be in 51-60 years age group. 2. There was female preponderance. 3. Obstruction is the most common presenting symptom found in 60% of cases followed by irreducibility (33.3% and strangulation (6.67%. 4. The onset of incisional hernias is more after 10 years following previous surgery. 5. Among 30 patients, bowel was viable in 18 patients (60% and mesh repair was done in 13 patients. Bowel was gangrenous in 12 patients (40% and anatomical repair was done in 17 patients. 6. Out of 30, women got infected in 11 patients (36.67% wound dehiscence noted in 5 patients (16.67%. 7. The recurrence rate was 6.67% with 6 months follow up. CONCLUSION 1. The mean

  13. Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  14. Fluvial facies reservoir productivity prediction method based on principal component analysis and artificial neural network

    Directory of Open Access Journals (Sweden)

    Pengyu Gao

    2016-03-01

    Full Text Available It is difficult to forecast the well productivity because of the complexity of vertical and horizontal developments in fluvial facies reservoir. This paper proposes a method based on Principal Component Analysis and Artificial Neural Network to predict well productivity of fluvial facies reservoir. The method summarizes the statistical reservoir factors and engineering factors that affect the well productivity, extracts information by applying the principal component analysis method and approximates arbitrary functions of the neural network to realize an accurate and efficient prediction on the fluvial facies reservoir well productivity. This method provides an effective way for forecasting the productivity of fluvial facies reservoir which is affected by multi-factors and complex mechanism. The study result shows that this method is a practical, effective, accurate and indirect productivity forecast method and is suitable for field application.

  15. Evolution of Early Pleistocene fluvial systems in central Poland prior to the first ice sheet advance – a case study from the Bełchatów lignite mine

    Directory of Open Access Journals (Sweden)

    Goździk Jan

    2017-06-01

    Full Text Available Deposits formed between the Neogene/Pleistocene transition and into the Early Pleistocene have been studied, mainly on the basis of drillings and at rare, small outcrops in the lowland part of Polish territory. At the Bełchatów lignite mine (Kleszczów Graben, central Poland, one of the largest opencast pits in Europe, strata of this age have long been exposed in extensive outcrops. The present paper is based on our field studies and laboratory analyses, as well as on research data presented by other authors. For that reason, it can be seen as an overview of current knowledge of lowermost Pleistocene deposits at Bełchatów, where exploitation of the Quaternary overburden has just been completed. The results of cartographic work, sedimentological, mineralogical and palynological analyses as well as assessment of sand grain morphology have been considered. All of these studies have allowed the distinction of three Lower Pleistocene series, i.e., the Łękińsko, Faustynów and Krzaki series. These were laid down in fluvial environments between the end of the Pliocene up to the advance of the first Scandinavian ice sheet on central Poland. The following environmental features have been interpreted: phases of river incision and aggradation, changes of river channel patterns, source sediments for alluvia, rates of aeolian supply to rivers and roles of fluvial systems in morphological and geological development of the area. The two older series studied, i.e., Łękińsko and Faustynów, share common characteristics. They were formed by sinuous rivers in boreal forest and open forest environments. The Neogene substratum was the source of the alluvium. The younger series (Krzaki formed mainly in a braided river setting, under conditions of progressive climatic cooling. Over time, a gradual increase of aeolian supply to the fluvial system can be noted; initially, silt and sand were laid down, followed by sand only during cold desert conditions. These

  16. Geological aspects of paleoseismicity and archaeosismology in the fluvial alluvial Rimac valley

    OpenAIRE

    Jacay, Javier

    2017-01-01

    The sedimentary fill of the Rimac River fluvial-alluvial plain (Upper Miocene-Quaternary) consists of a thick sequence of unconsolidated material that corresponds to fluvial deposits. A record of seismotectonic activity is presentedin the sedimentary levels of fine facie within numerous paleoseismic structures such as contoured layers, pseudonodules, load figures, and material injections. Additionally, wall inclination and collapse, as well as displacement and partialfracturing, and pavement ...

  17. De Qeurvian Tenosynovitis: Clinical Outcomes of Surgical Treatment with Longitudinal and Transverse Incision

    Directory of Open Access Journals (Sweden)

    Arefah Dehghani Tafti

    2011-03-01

    Full Text Available AbstractObjectives: De Quervain disease is a mechanical tenosynovitis due to inadequacy volume between abductor pollicis longus, extensor pollicis brevis and their tunnel. Treatment methods include immobilization, steroid injections, and operation. For the first time Fritz De Quervain described surgical treatment of this disease. Since then, various ways of treatment have been reported. The purpose of this study is to compare the clinical outcomes of a longitudinal incision with a transverse incision in De Quervain disease.Methods: This was a randomized controlled clinical trial conducted in three hospitals in Iran, Yazd from March 2003 to September 2008. One hundred-twenty patients with De Quervain disease who did not respond to conservative treatment were operated with two different incisions. The patients were followed for three months to compare the surgical outcomes.Results: During a three month follow-up, a significant difference was shown between the two methods (p=0.03. Results of surgical treatment with longitudinal incision were excellent (only 5 hypertrophic scars, but there were 13 postoperative complaints with transverse incision.Conclusion: According to our findings, longitudinal incision in surgical treatment of De Quervain disease is better than transverse incision.

  18. Nuclear management in manual small incision cataract surgery by snare technique

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debasish

    2009-01-01

    Full Text Available Manual small incision cataract surgery has evolved into a popular method of cataract surgery in India. However, in supra hard cataract, bringing out the whole nucleus through the sclerocorneal flap valve incision becomes difficult. A bigger incision required in such cataracts loses its value action, as the internal incision and corneal valve slips beyond the limbus into sclera. Struggling with the supra hard cataracts through a regular small incision. Phacofracture in the anterior chamber becomes a useful option in these cases. In the snare technique, a stainless steel wire loop when lassoed around the nucleus in the anterior chamber constricts from the equator, easily dividing the hardest of the nuclei into two halves. The wire loop constricts in a controlled way when the second cannula of snare is pulled. The divided halves can easily be brought out by serrated crocodile forceps. This nuclear management can be safely performed through a smaller sclerocorneal flap valve incision where the corneal valve action is retained within the limbus without sutures, and the endothelium or the incision is not disturbed. However, the technique requires space in the anterior chamber to maneuver the wire loop and anterior chamber depth more than 2.5 mm is recommended. Much evidence to this wonderful technique is not available in literature, as its popularity grew through live surgical workshops and small interactive conferences.

  19. Characterizing fluvial heavy metal pollutions under different rainfall conditions: Implication for aquatic environment protection.

    Science.gov (United States)

    Zhang, Lixun; Zhao, Bo; Xu, Gang; Guan, Yuntao

    2018-09-01

    Globally, fluvial heavy metal (HM) pollution has recently become an increasingly severe problem. However, few studies have investigated the variational characteristics of fluvial HMs after rain over long periods (≥1 year). The Dakan River in Xili Reservoir watershed (China) was selected as a case study to investigate pollution levels, influencing factors, and sources of HMs under different rainfall conditions during 2015 and 2016. Fluvial HMs showed evident spatiotemporal variations attributable to the coupled effects of pollution generation and rainfall diffusion. Fluvial HM concentrations were significantly associated with rainfall characteristics (e.g., rainfall intensity, rainfall amount, and antecedent dry period) and river flow, which influenced the generation and the transmission of fluvial HMs in various ways. Moreover, this interrelationship depended considerably on the HM type and particle size distribution. Mn, Pb, Cr, and Ni were major contributors to high values of the comprehensive pollution index; therefore, they should be afforded special attention. Additionally, quantitative source apportionment of fluvial HMs was conducted by combining principal component analysis with multiple linear regression and chemical mass balance models to obtain comprehensive source profiles. Finally, an environment-friendly control strategy coupling "source elimination" and "transport barriers" was proposed for aquatic environment protection. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Complications of femtosecond laser corneal small incision lenticule extraction

    Directory of Open Access Journals (Sweden)

    Qing-Hong Lin

    2017-07-01

    Full Text Available AIM:To investigate the safety and complications of femtosecond laser corneal small incision lenticule extraction(SMILEprocedure and discuss the prevention and treatment.METHODS: We retrospectively studied the complications of 403 patients(799 eyeswith myopia and myopic astigmatism treated by SMILE.RESULTS: All the patients underwent the operation successfully. Only 1 case(1 eyesuffered from dark spot and changed to femtosecond laser-assisted LASIK(FS-LASIK, 5 cases(5 eyes, 0.6%suffered from the suction loss, 11 cases(17 eyes, 2.1%developed opaque bubble layer. All patients gained perfect uncorrected visual acuity(UCVA(20/20. The best corrected visual acuity(BCVAdid not decrease after operations. The incidence of haze and diffuse lamellar keratitis was low(0.3% and 0.4%, respectivelyand no other complications were observed. There was 9 eyes in 6 patients(1.1%found regression of refraction at 6mo after surgery, while the UCVA of rest patients reached 1.0 at 3mo after surgery.CONCLUSION: The SMILE procedure has high safety for myopia and myopic astigmatism. Effective prevention and management of the complications is the key to achieve the satisfactory visual acuity.

  1. Single-Incision Laparoscopic Sterilization of the Cheetah (Acinonyx jubatus).

    Science.gov (United States)

    Hartman, Marthinus J; Monnet, Eric; Kirberger, Robert M; Schmidt-Küntzel, Anne; Schulman, Martin L; Stander, Jana A; Stegmann, George F; Schoeman, Johan P

    2015-07-01

    To describe laparoscopic ovariectomy and salpingectomy in the cheetah (Acinonyx jubatus) using single-incision laparoscopic surgery (SILS). Prospective cohort. Female cheetahs (Acinonyx jubatus) (n = 21). Cheetahs were randomly divided to receive either ovariectomy (n = 11) or salpingectomy (n = 10). The use and complications of a SILS port was evaluated in all of cheetahs. Surgery duration and insufflation volumes of carbon dioxide (CO2 ) were recorded and compared across procedures. Laparoscopic ovariectomy and salpingectomy were performed without complications using a SILS port. The poorly-developed mesosalpinx and ovarian bursa facilitated access to the uterine tube for salpingectomy in the cheetah. The median surgery duration for ovariectomy was 24 minutes (interquartile range 3) and for salpingectomy was 19.5 minutes (interquartile range 3) (P = .005). The median volume of CO2 used for ovariectomy was 11.25 L (interquartile range 3.08) and for salpingectomy was 4.90 L (interquartile range 2.52), (P = .001) CONCLUSIONS: Laparoscopic ovariectomy and salpingectomy can be performed in the cheetah using SILS without perioperative complications. Salpingectomy is faster than ovariectomy and requires less total CO2 for insufflation. © Copyright 2015 by The American College of Veterinary Surgeons.

  2. Ultrasonographic evaluation of the healing of ventral midline abdominal incisions in the horse.

    Science.gov (United States)

    Wilson, D A; Badertscher, R R; Boero, M J; Baker, G J; Foreman, J H

    1989-06-01

    Ultrasonography was used to evaluate the ventral midline incisions of 21 ponies following exploratory laparotomy. The incisions were evaluated before surgery and at weekly intervals from one to seven weeks after surgery. Both 5.0 and 7.5 MHz linear array and 7.5 MHz sector transducers were used for the evaluations. The incisional complications observed were drainage, oedema, suture sinus formation, suture abscess, superficial dehiscence and incisional hernia. Ultrasonographic imaging of the ventral midline incision was an easy, reliable and objective method for detecting and monitoring the progression of incisional complications in a non-invasive manner.

  3. Towards achieving small-incision cataract surgery 99.8% of the time.

    Directory of Open Access Journals (Sweden)

    Thomas R

    2000-01-01

    Full Text Available A surgical approach designed to reliably attain the modern goal of small incision cataract surgery 99.8% of the time is described. Phacoemulsification as well as a manual small incision technique is utilised to achieve the desired outcome as often as possible and for all types of cataracts. The logic, and required surgical steps are described and illustrated. This surgical technique allows the advantages of small incision surgery to be reliably achieved. The method is flexible and allows decisions and steps to be modified depending on the skill and comfort zone of the individual surgeon.

  4. Techniques for creating inconspicuous face-lift scars: avoiding visible incisions and loss of temporal hair.

    Science.gov (United States)

    Kridel, Russell W H; Liu, Edmund S

    2003-01-01

    Patients seeking rhytidectomy desire an improved neckline, jawline, and midface, but rarely at the price of signs that betray a face-lift, namely, visible incisions. We describe our face-lift incisional planning and the rationale behind specific surgical maneuvers for preventing unwanted sequelae. The telltale signs of poorly placed incisions include temporal hair loss, conspicuous scars, an unnatural appearance to the tragus, and a posterior hairline distorsion. Special considerations are given to the male patient and to the salvage of readily visible incision lines from previous surgery.

  5. Transverse versus Longitudinal Incisions for Femoral Artery Exposure in Treating Patients with Peripheral Vascular Disease.

    Science.gov (United States)

    Parikh, Punam P; Rubio, Gustavo A; Patel, Kunal; Gupta, Kapil; Jones, Keith; Rey, Jorge; Robinson, Handel

    2018-02-01

    This study evaluates differences in wound complication rate when transverse versus longitudinal incision is utilized to expose femoral vessels in managing patients with peripheral vascular disease. A retrospective review from 2013 to 2015 was conducted of 150 patients undergoing 156 lower extremity revascularizations with femoral artery exposure through a groin incision. Patients were stratified into 2 groups, transverse versus longitudinal groin incision. Data were reviewed for 3 surgeons that utilize either transverse or longitudinal groin incision in patients undergoing common or iliofemoral endarterectomies, or where femoral artery was used as inflow and/or outflow vessel for limb revascularization. Each group had a comparative outcomes analysis based on incision type. The primary outcome was wound complication, defined as any wound infection, lymphocele, hematoma, dehiscence, pseudoaneurysm, or necrosis. Other outcomes studied included unplanned return to operating room for wound complication, wound vacuum therapy, and soft-tissue flap closure. Data were analyzed using 2-tailed chi-squared test and Student's t-test. Patients in the transverse (n = 85 cases) versus longitudinal (n = 71 cases) cohorts were similar in relation to demographics and comorbidities. Overall mean follow-up was 220 days. Patients with a transverse as compared to longitudinal incision had a significantly lower overall wound complication rate, 7% vs. 42%, respectively (P transverse incisions were associated with lower incidence of unplanned return to the operating room to manage wound complications than patients with a longitudinal incision (5% vs. 23%, respectively; P Transverse versus longitudinal incisions were also associated with significantly lower need for wound vacuum therapy (6% vs. 15%, respectively; P Transverse groin incisions for femoral artery exposure may offer a lower risk of wound complications for open procedures as compared to a longitudinal incision

  6. Geochemistry of Fluvial Sediments from Geregu, Southwest Nigeria

    Directory of Open Access Journals (Sweden)

    Adiotomre Emmanuel E.

    2017-03-01

    Full Text Available Geochemical analysis of fluvial sediments on the banks of River Ero using inductively coupled plasma mass spectrometry illustrates their maturity, provenance and tectonic setting. The analysed sediment samples show low SiO2/Al2O3 ratios of 2.92-2.99 (units FL_A, FL_B and FL_E and high SiO2/Al2O3 ratios of 4.064-4.852 (units FL_C, FL_D, FL_F and FL_G. Sediments were geochemically classified as shales (units FL_A, FL_B and FL_E and greywackes (units FL_C, FL_D, FL_F and FL_G. Variability in sediment maturity (FL_F > FL_G >FL_C >FL_D >FL_A > FL_B > FL_E parallels a decreasing order in the ratios of SiO2/Al2O3 and K2O/Al2O3, as well as the proportion of quartz grains and matrix components. Evidence from Al2O3/TiO2, K2O, Rb, La/Co, Th/Co, Cr/ Th, Th/Cr, La/Th-Hf, Th-Hf-Co and rare earth element contents of sediment samples suggest felsic protoliths of upper continental crust in a passive margin tectonic setting. An insignificant contribution of mafic components from the source is, however, inferred based on the Ni and Cr contents of the sediment samples. Combined Eu anomalies <0.85 and (Gd/Ybn ratios <2.0 (1.53- 1.82, average 1.65 suggest post-Archean protoliths.

  7. Femtosecond laser effect on the self-sealing properties of the corneal incision of various lengths and profile (experimental trial

    Directory of Open Access Journals (Sweden)

    Yulduz Shavkatovna Nizametdinova

    2015-06-01

    Full Text Available An experimental investigation was carried out to study self-sealing properties of corneal incisions of different profile and length carried out with femtosecond laser Victus (Technolas Perfect Vision/Bausch&Lomb. Using femtosecond laser for this purpose allows creating corneal incisions of high precision and predictability. Reproducibility and standardization of the incision profile and length are an advantage of this technology. Obtained results showed that single-profile incisions are less stable and safe when compared to multi-profile ones. It was noted that incision length increase promotes its self-sealing properties.

  8. Phacoemulsification versus small incision cataract surgery in patients with uveitis

    Directory of Open Access Journals (Sweden)

    Rahul Bhargava

    2015-10-01

    Full Text Available AIM: To compare the safety and efficacy of phacoemulsification and small incision cataract surgery (SICS in patients with uveitic cataract.METHODS:In aprospective, randomized multi-centric study, consecutive patients with uveitic cataract were randomized to receive phacoemulsification or manual SICS by either of two surgeons well versed with both the techniques. A minimum inflammation free period of 3mo (defined as less than 5 cells per high power field in anterior chamber was a pre-requisite for eligibility for surgery. Superior scleral tunnel incisions were used for both techniques. Improvement in visual acuity post-operatively was the primary outcome measure and the rate of post-operative complications and surgical time were secondary outcome measures, respectively. Means of groups were compared using t-tests. One way analysis of variance (ANOVA was used when there were more than two groups. Chi-square tests were used for proportions. Kaplan Meyer survival analysis was done and means for survival time was estimated at 95% confidence interval (CI. A P value of <0.05 was considered statistically significant.RESULTS:One hundred and twenty-six of 139 patients (90.6% completed the 6-month follow-up. Seven patients were lost in follow up and another six excluded due to either follow-up less than six months (n=1 or inability implant an intraocular lens (IOL because of insufficient capsular support following posterior capsule rupture (n=5. There was significant improvement in vision after both the procedures (paired t-test; P<0.001. On first postoperative day, uncorrected distance visual acuity (UDVA was 20/63 or better in 31 (47% patients in Phaco group and 26 (43.3% patients in SICS group (P=0.384. The mean surgically induced astigmatism (SIA was 0.86±0.34 dioptres (D in the phacoemulsification group and 1.16±0.28 D in SICS group. The difference between the groups was significant (t-test, P=0.002. At 6mo, corrected distance visual acuity (CDVA

  9. Single incision laparoscopic cholecystectomy using the one-incision three-trocar technique with all straight instruments: how I do it?

    Institute of Scientific and Technical Information of China (English)

    Hongyi Cui

    2011-01-01

    Single incision laparoscopic surgery (SILS) is a novel minimally invasive surgical technique that is gaining popularity around the world.One of the most commonly performed procedures is single incision laparoscopic cholecystectomy (SILC).Most reported techniques utilize special purpose-made access port and articulating instruments,rendering the procedure costly and difficult to learn.This article provides a stepwise description of SILC technique using all straight instruments without the need for a special port.It aims to shorten the learning curve for surgeons wishing to adopt a safe and cost-effective SILC technique to their practice.

  10. Comparison of Radiofrequency and Electrocautery With Conventional Scalpel Incisions.

    Science.gov (United States)

    Hasar, Zafer Burak; Ozmeric, Nurdan; Ozdemir, Burcu; Gökmenoğlu, Ceren; Baris, Emre; Altan, Gökçen; Kahraman, Sevil

    2016-11-01

    The disadvantages of conventional scalpels, including insufficient control of bleeding, prompted us to search for new alternative methods such as electrosurgery and radiosurgery. In this study, the conventional scalpel was compared with radiosurgery and electrosurgery for wound healing with assessment of lateral heat production, inflammation, and instrument performance. Incisions were made in the palatal mucosa of 42 Wistar rats using a scalpel, electrocautery instrument, or radiofrequency instrument. Postoperative hemostasis, tissue coagulation, and tissue sticking were measured, and pain evaluation through weight loss was recorded. Gingival biopsy specimens from the surgical area were obtained at the time of surgery and 2, 4, 7, and 14 days postoperatively and were evaluated immunohistochemically for inducible nitric oxide synthase and heat shock protein 70. Kruskal-Wallis, 1-way analysis of variance, and Mann-Whitney U tests were used for statistical evaluation. The rats in the electrosurgery and radiosurgery groups had aggressively greater weight loss when compared with the scalpel group in the first 7 days. Hemostasis was better in the electrocautery group, tissue coagulation was greater in the radiofrequency group (P < .001), and tissue sticking was lesser in the scalpel group (P < .001) compared with the other groups. Inducible nitric oxide synthase expression and heat shock protein 70 expression were similar in all 3 groups. Electrosurgery performed better regarding hemostasis, whereas a scalpel was superior in terms of tissue sticking and tissue coagulation. Radiosurgery was superior regarding hemostasis when compared with a conventional scalpel, but it was not as successful as electrosurgery. Copyright © 2016. Published by Elsevier Inc.

  11. The formation of double-strand breaks at multiply damaged sites is driven by the kinetics of excision/incision at base damage in eukaryotic cells

    International Nuclear Information System (INIS)

    Kozmin, S.G.; Sedletska, Y.; Reynaud-Angelin, A.; Sage, E.; Kozmin, S.G.; Sedletska, Y.; Reynaud-Angelin, A.; Sage, E.; Gasparutto, D.

    2009-01-01

    It has been stipulated that repair of clustered DNA lesions may be compromised, possibly leading to the formation of double-strand breaks (DSB) and, thus, to deleterious events. Using a variety of model multiply damaged sites (MDS), we investigated parameters that govern the formation of DSB during the processing of MDS. Duplexes carrying MDS were inserted into replicative or integrative vectors, and used to transform yeast Saccharomyces cerevisiae. Formation of DSB was assessed by a relevant plasmid survival assay. Kinetics of excision/incision and DSB formation at MDS was explored using yeast cell extracts. We show that MDS composed of two uracils or abasic sites, were rapidly incised and readily converted into DSB in yeast cells. In marked contrast, none of the MDS carrying opposed oG and hU separated by 38 bp gave rise to DSB, despite the fact that some of them contained preexisting single-strand break (a 1-nt gap). Interestingly, the absence of DSB formation in this case correlated with slow excision/incision rates of lesions. We propose that the kinetics of the initial repair steps at MDS is a major parameter that direct towards the conversion of MDS into DSB. Data provides clues to the biological consequences of MDS in eukaryotic cells. (authors)

  12. Glacial lake outburst floods and fluvial erosion in the Himalaya - insights from the 2016 Bhote Koshi GLOF

    Science.gov (United States)

    Cook, K. L.; Gimbert, F.; Andermann, C.; Hovius, N.; Adhikari, B. R.

    2017-12-01

    The Himalaya is a region of rapid erosion where fluvial processes are assumed to be driven by precipitation delivered during the annual Indian Summer Monsoon. However, the rivers in this region are also subject to catastrophic floods caused by the failure of glacial lake and landslide dams. Because these floods are rarely observed, it has been difficult to isolate their impact on the rivers and adjacent hillslopes, and their importance for the long-term evolution of Himalayan valleys is largely unknown. In July 2016, the Bhotekoshi/Sunkoshi River in central Nepal was hit by a glacial lake outburst flood (GLOF) that caused substantial changes to the channel bed, banks, and adjacent hillslopes, causing at least 26 landslides and an average of 11 m of channel widening. The flood passed through a seismic and hydrological observatory installed along the river in June 2015, and we have used the resulting data to constrain the timing, duration, and bedload transport properties of the outburst flood. The impact of the flood on the river can be further observed with hourly time-lapse photographs, daily measurements of suspended sediment load, repeat lidar surveys, and satellite imagery. The outburst flood affected the river on several timescales. In the short term, it transported large amounts of coarse sediment and restructured the river bed during the hours of the flood pulse itself. Over intermediate timescales it resulted in elevated bedload and suspended load transport for several weeks following the flood. Over longer timescales the flood undercut and destabilized the river banks and hillslopes in a number of locations, leading to bank collapses, slumps, and landslides. Our data indicate that impacts of the GLOF far exceed those driven by the annual summer monsoon, likely due to extremely coarse sediment that armors much of the channel. The relatively frequent occurrence of GLOFs and the extremely high discharges relative to monsoon floods suggest that GLOFs may

  13. Kualitas Pengeringan Kayu Mahoni pada Berbagai Variasi Kerapatan Incising dengan Dua Skedul Pengeringan Suhu tinggi

    Directory of Open Access Journals (Sweden)

    Tomy Listyanto

    2016-11-01

    Full Text Available Tujuan dari penelitian ini adalah untuk mengetahui pengaruh interaksi variasi kerapatan incising dan dua skedul pengeringan terhadap kecepatan dan cacat-cacat pengeringan kayu mahoni, serta mengetahui pengaruh variasi kerapatan incising terhadap kekuatan lengkung statik kayu mahoni yang telah dikeringkan. Tiga pohon mahoni (Swietenia mahagony berdiameter 300-350 mm ditebang dan selanjutnya dibelah dan dibuat menjadi balok dengan ukuran 60 mm × 100 mm dengan panjang 500 mm untuk dijadikan sampel pengeringan. Di antara masing-masing bagian tersebut, dibuat sampel ukuran 20 mm × 20 mm × 25 mm, yang digunakan untuk penentu kadar air awal dan distribusinya. Sampel pengeringan selanjutnya dibagi menjadi 5 variasi kerapatan incising, yaitu 0 lubang/m2 (tanpa incising, 1000 lubang/m2, 2000 lubang/m2, 3000 lubang/m2, dan 4000 lubang/m2. Setiap variasi kerapatan incising selanjutnya akan dikeringkan dengan 2 skedul pengeringan, yaitu suhu pengeringan 100°C sampai tercapai kadar air akhir 12% dan suhu 60°C pada 8 jam pertama dan selanjutnya dilanjutkan 100°C, sampai tercapai kadar air akhir 12%. Paramater yang diamati adalah kecepatan pengeringan, cacat retak permukaan, dan distribusi kadar air akhir. Hasil analisis menunjukkan bahwa kerapatan incising 3000-4000 lubang/m2 memberikan pengaruh yang cukup nyata di dalam mempercepat proses pengeringan dan distribusi kadar air akhir. Skedul pengeringan dan variasi kerapatan incising tidak berpengaruh pada retak permukaan. Pra perlakuan incising sampai batas 4000 lubang/m2 ini dapat diterapkan untuk mempercepat proses pengeringan dengan penurunan nilai modulus elastisitas dan modulus patah yang tidak berbeda nyata. Kata kunci: incising, pengeringan suhu tinggi, mahoni, lengkung statik, skedul pengeringan   Drying Quality of Mahoni Wood in Various Incising Densities and Two High Temperature-Drying Schedules Abstract The aims of this research were to investigate the effects of interaction

  14. Relaxation incisions of venomous snake "Japanese mamushi" bites to the hand

    Directory of Open Access Journals (Sweden)

    Sugamata A

    2011-12-01

    Full Text Available Akira Sugamata, Naoki Yoshizawa, Takahiro OkadaDepartment of Plastic and Reconstructive Surgery, Tokyo Medical University Hachioji Medical Center, Tokyo, JapanAbstract: Gloydius blomhoffii, commonly known as Japanese mamushi, is a venomous viper species found widely in Japan. The most frequently bitten regions are the fingers and toes, and severe swelling causes compression of peripheral arteries and/or compartment syndrome of the extremities. We experienced four cases of mamushi bites to the hand, and undertook relaxation incision in the hands of three of these patients. As a result, the patients who underwent relaxation incision did not show any skin necrosis or permanent sensory disturbance in the affected fingers. Relaxation incision can be useful to not only decompress subcutaneous and compartment pressure of the hand, but also to wash out the venom from the bitten region by improving venous and lymphatic drainage.Keywords: mamushi, snakebite, viper, relaxation incision

  15. Treatment for incarcerated indirect hernia with "Cross-Internal Ring" inguinal oblique incision in children.

    Science.gov (United States)

    Yan, Xue-Qiang; Yang, Jun; Zheng, Nan-Nan; Kuang, Hou-Fang; Duan, Xu-Fei; Bian, Hong-Qiang

    2017-01-01

    This study aims to evaluate the utility of the "Cross-Internal Ring" inguinal oblique incision for the surgical treatment of incarcerated indirect hernia (IIH) complicated with severe abdominal distension. Patients of IIH complicated with severe abdominal distension were reviewed retrospectively. All patients received operation through the "Cross-Internal Ring" inguinal oblique incision. There were totally 13 patients were included, male to female ratio was 9-4. The time for patients to resume oral feeding varying from 2 to 5 days after operation, no complications include delayed intestinal perforation, intra-abdominal abscess, and incision infection happened. Average postoperative hospital stay was 5.2 days. All cases were followed up for 6-18 months. No recurrence or iatrogenic cryptorchidism happened. "Cross-Internal Ring" inguinal oblique incision is a simple, safe, and reliable surgical method to treat pediatric IIH complicated with severe abdominal distension.

  16. Treatment for incarcerated indirect hernia with “Cross-Internal Ring” inguinal oblique incision in children

    Directory of Open Access Journals (Sweden)

    Xue-Qiang Yan

    2017-01-01

    Full Text Available Background: This study aims to evaluate the utility of the “Cross-Internal Ring” inguinal oblique incision for the surgical treatment of incarcerated indirect hernia (IIH complicated with severe abdominal distension. Materials and Methods: Patients of IIH complicated with severe abdominal distension were reviewed retrospectively. All patients received operation through the “Cross-Internal Ring” inguinal oblique incision. Results: There were totally 13 patients were included, male to female ratio was 9-4. The time for patients to resume oral feeding varying from 2 to 5 days after operation, no complications include delayed intestinal perforation, intra-abdominal abscess, and incision infection happened. Average postoperative hospital stay was 5.2 days. All cases were followed up for 6–18 months. No recurrence or iatrogenic cryptorchidism happened. Conclusion: “Cross-Internal Ring” inguinal oblique incision is a simple, safe, and reliable surgical method to treat pediatric IIH complicated with severe abdominal distension.

  17. Cochlear implantation with Pulsar Med El: a novel small incision technique.

    Science.gov (United States)

    Cuda, D

    2009-04-01

    Although still widely implanted, Pulsar Med-El is rarely considered for small incision approach. Overall, 30 teen-age and adult patients were operated upon with a novel small incision (4-5 cm). Full insertion of the electrode array was achieved in all cases. No major intra-operative complications occurred. At follow-up, no flap-related complications and no migration of the receiver-stimulator were observed in the "device suture" (14 patients) or "no device suture" groups (16 patients). All patients are full-time users of the device. In conclusion, a small incision for the Pulsar Med-El cochlear implant is feasible, safe and reproducible. Ligature fixation of the device is not critical with this operation. Also with this device, in adult and teen-age patients, it is, therefore, possible to retain several typical advantages of small incision approaches.

  18. Evaluation of a new disposable silicon limbal relaxing incision knife by experienced users

    OpenAIRE

    Parvu Valentin; Dugue Geoffrey; Albanese John; Bajart Ann M; Lee Edwin

    2009-01-01

    Abstract Background Previous research has suggested that the silicon BD Atomic Edge™ knife has superior performance characteristics when compared to a metal knife and performance similar to diamond knife when making various incisions. This study was designed to determine whether a silicon accurate depth knife has equivalent performance characteristics when compared to a diamond limbal relaxing incision (LRI) knife and superior performance characteristics when compared to a steel accurate dept...

  19. Aorta-atria-septum combined incision for aortic valve re-replacement

    Science.gov (United States)

    Xu, Yiwei; Ye, Xiaofeng; Li, Zhaolong

    2018-01-01

    This case report illustrates a patient who underwent supra-annular mechanical aortic valve replacement then suffered from prosthesis dysfunction, increasing pressure gradient with aortic valve. She was successfully underwent aortic valve re-replacement, sub-annular pannus removing and aortic annulus enlargement procedures through combined cardiac incision passing through aortic root, right atrium (RA), and upper atrial septum. This incision provides optimal visual operative field and simplifies dissection. PMID:29850170

  20. Type of incision does not predict abdominal wall outcome after emergency surgery for colonic anastomotic leakage

    DEFF Research Database (Denmark)

    Jensen, Kristian Kiim; Oma, Erling; Harling, Henrik

    2017-01-01

    for anastomotic leakage were included with a median follow-up of 5.4 years. Incisional hernia occurred in 41 of 227 (15.3%) patients undergoing midline incision compared with 14 of 81 (14.7%) following transverse incision, P = 1.00. After adjusting for confounders, there was no association between the type...... not predict abdominal wall outcome after emergency surgery for colonic anastomotic leakage....

  1. Laser incising of wood: Impregnation of columns with water-soluble dye

    International Nuclear Information System (INIS)

    Hattori, N.; Ando, K.; Kitayama, S.; Nakamura, Y.

    1994-01-01

    To know whether or not laser incising is a useful pre-treatment technique in impregnating a chemical fluid into lumber, pin holes were made in columns of hinoki (Chamaecyparis obtusa Endl.), sugi (Cryptomeria japonica D. Don), karamatsu (Larix leptolepis Gordon) and douglas-fir (Pseudo-tsuga menziesii Franco) with 1.7 kW CO2 laser, and a water-soluble dye was impregnated into these columns with a local pressure impregnation device. Retentions, and lengths and widths of penetrations from each hole were measured quantitatively. Referring to the results of the preparatory experiment mentioned above, incising patterns for sugi and douglas-fir were designed, and the same water-soluble dye was impregnated into the laser-incised columns as well as into non-incised ones with the vacuum-pressure method to obtain penetrated layers with the target depths completely. As a result, a retention of 200 kg/m3 of dye could be achieved for a column of douglas-fir even if it is a species difficult to impregnate. The penetrated layer also could be formed completely at the depth of the laser incision. Therefore, it is concluded that laser incising can be used for the pre-treatment before impregnation of wood columns. (author)

  2. Evaluation of a new disposable silicon limbal relaxing incision knife by experienced users.

    Science.gov (United States)

    Albanese, John; Dugue, Geoffrey; Parvu, Valentin; Bajart, Ann M; Lee, Edwin

    2009-12-21

    Previous research has suggested that the silicon BD Atomic Edge knife has superior performance characteristics when compared to a metal knife and performance similar to diamond knife when making various incisions. This study was designed to determine whether a silicon accurate depth knife has equivalent performance characteristics when compared to a diamond limbal relaxing incision (LRI) knife and superior performance characteristics when compared to a steel accurate depth knife when creating limbal relaxing incision. Sixty-five ophthalmic surgeons with limbal relaxing incision experience created limbal relaxing incisions in ex-vivo porcine eyes with silicon and steel accurate depth knives and diamond LRI knives. The ophthalmic surgeons rated multiple performance characteristics of the knives on Visual Analog Scales. The observed differences between the silicon knife and diamond knife were found to be insignificant. The mean ratio between the performance of the silicon knife and the diamond knife was shown to be greater than 90% (with 95% confidence). The silicon knife's mean performance was significantly higher than the performance of the steel knife for all characteristics. (p-value knife was found to be equivalent in performance to the diamond LRI knife and superior to the steel accurate depth knife when making limbal relaxing incisions in ex vivo porcine eyes. Disposable silicon LRI knives may be an alternative to diamond LRI knives.

  3. Evaluation of a new disposable silicon limbal relaxing incision knife by experienced users

    Directory of Open Access Journals (Sweden)

    Parvu Valentin

    2009-12-01

    Full Text Available Abstract Background Previous research has suggested that the silicon BD Atomic Edge™ knife has superior performance characteristics when compared to a metal knife and performance similar to diamond knife when making various incisions. This study was designed to determine whether a silicon accurate depth knife has equivalent performance characteristics when compared to a diamond limbal relaxing incision (LRI knife and superior performance characteristics when compared to a steel accurate depth knife when creating limbal relaxing incision. Methods Sixty-five ophthalmic surgeons with limbal relaxing incision experience created limbal relaxing incisions in ex-vivo porcine eyes with silicon and steel accurate depth knives and diamond LRI knives. The ophthalmic surgeons rated multiple performance characteristics of the knives on Visual Analog Scales. Results The observed differences between the silicon knife and diamond knife were found to be insignificant. The mean ratio between the performance of the silicon knife and the diamond knife was shown to be greater than 90% (with 95% confidence. The silicon knife's mean performance was significantly higher than the performance of the steel knife for all characteristics. (p-value Conclusions For experienced users, the silicon accurate depth knife was found to be equivalent in performance to the diamond LRI knife and superior to the steel accurate depth knife when making limbal relaxing incisions in ex vivo porcine eyes. Disposable silicon LRI knives may be an alternative to diamond LRI knives.

  4. In vitro conjunctival incision repair by temperature-controlled laser soldering.

    Science.gov (United States)

    Norman, Galia; Rabi, Yaron; Assia, Ehud; Katzir, Abraham

    2009-01-01

    The common method of closing conjunctival incisions is by suturing, which is associated with several disadvantages. It requires skill to apply and does not always provide a watertight closure, which is required in some operations (e.g., glaucoma filtration). The purpose of the present study was to evaluate laser soldering as an alternative method for closing conjunctival incisions. Conjunctival incisions of 20 ex vivo porcine eyes were laser soldered using a temperature-controlled fiberoptic laser system and an albumin mixed with indocyanine green as a solder. The control group consisted of five repaired incisions by a 10-0 nylon running suture. The leak pressure of the repaired incisions was measured. The mean leak pressure in the laser-soldered group was 132 mm Hg compared to 4 mm Hg in the sutured group. There was no statistically significant difference in both the incision's length and distance from the limbus between the groups, before and after the procedure, indicating that there was no severe thermal damage. These preliminary results clearly demonstrate that laser soldering may be a useful method for achieving an immediate watertight conjunctival wound closure. This procedure is faster and easier to apply than suturing.

  5. Incision extension is the optimal method of difficult gallbladder extraction at laparoscopic cholecystectomy.

    Science.gov (United States)

    Bordelon, B M; Hobday, K A; Hunter, J G

    1992-01-01

    An unsolved problem of laparoscopic cholecystectomy is the optimal method of removing the gallbladder with thick walls and a large stone burden. Proposed solutions include fascial dilatation, stone crushing, and ultrasonic, high-speed rotary, or laser lithotripsy. Our observation was that extension of the fascial incision to remove the impacted gallbladder was time efficient and did not increase postoperative pain. We reviewed the narcotic requirements of 107 consecutive patients undergoing laparoscopic cholecystectomy. Fifty-two patients required extension of the umbilical incision, and 55 patients did not have their fascial incision enlarged. Parenteral meperidine use was 39.5 +/- 63.6 mg in the patients requiring fascial incision extension and 66.3 +/- 79.2 mg in those not requiring fascial incision extension (mean +/- standard deviation). Oral narcotic requirements were 1.1 +/- 1.5 doses vs 1.3 +/- 1.7 doses in patients with and without incision extension, respectively. The wide range of narcotic use in both groups makes these apparent differences not statistically significant. We conclude that protracted attempts at stone crushing or expensive stone fragmentation devices are unnecessary for the extraction of a difficult gallbladder during laparoscopic cholecystectomy.

  6. Temperature-controlled laser-soldering system and its clinical application for bonding skin incisions

    Science.gov (United States)

    Simhon, David; Gabay, Ilan; Shpolyansky, Gregory; Vasilyev, Tamar; Nur, Israel; Meidler, Roberto; Hatoum, Ossama Abu; Katzir, Abraham; Hashmonai, Moshe; Kopelman, Doron

    2015-12-01

    Laser tissue soldering is a method of repairing incisions. It involves the application of a biological solder to the approximated edges of the incision and heating it with a laser beam. A pilot clinical study was carried out on 10 patients who underwent laparoscopic cholecystectomy. Of the four abdominal incisions in each patient, two were sutured and two were laser soldered. Cicatrization, esthetical appearance, degree of pain, and pruritus in the incisions were examined on postoperative days 1, 7, and 30. The soldered wounds were watertight and healed well, with no discharge from these wounds or infection. The total closure time was equal in both methods, but the net soldering time was much shorter than suturing. There was no difference between the two types of wound closure with respect to the pain and pruritus on a follow-up of one month. Esthetically, the soldered incisions were estimated as good as the sutured ones. The present study confirmed that temperature-controlled laser soldering of human skin incisions is clinically feasible, and the results obtained were at least equivalent to those of standard suturing.

  7. Watershed-scale modeling of streamflow change in incised montane meadows

    Science.gov (United States)

    Essaid, Hedeff I.; Hill, Barry R.

    2014-01-01

    Land use practices have caused stream channel incision and water table decline in many montane meadows of the Western United States. Incision changes the magnitude and timing of streamflow in water supply source watersheds, a concern to resource managers and downstream water users. The hydrology of montane meadows under natural and incised conditions was investigated using watershed simulation for a range of hydrologic conditions. The results illustrate the interdependence between: watershed and meadow hydrology; bedrock and meadow aquifers; and surface and groundwater flow through the meadow for the modeled scenarios. During the wet season, stream incision resulted in less overland flow and interflow and more meadow recharge causing a net decrease in streamflow and increase in groundwater storage relative to natural meadow conditions. During the dry season, incision resulted in less meadow evapotranspiration and more groundwater discharge to the stream causing a net increase in streamflow and a decrease in groundwater storage relative to natural meadow conditions. In general, for a given meadow setting, the magnitude of change in summer streamflow and long-term change in watershed groundwater storage due to incision will depend on the combined effect of: reduced evapotranspiration in the eroded meadow; induced groundwater recharge; replenishment of dry season groundwater storage depletion in meadow and bedrock aquifers by precipitation during wet years; and groundwater storage depletion that is not replenished by precipitation during wet years.

  8. In patients with extensive subcutaneous emphysema, which technique achieves maximal clinical resolution: infraclavicular incisions, subcutaneous drain insertion or suction on in situ chest drain?

    Science.gov (United States)

    Johnson, Charles H N; Lang, Sommer A; Bilal, Haris; Rammohan, Kandadai S

    2014-06-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: 'In patients with extensive subcutaneous emphysema, which technique achieves maximal clinical resolution: infraclavicular incisions, subcutaneous drain insertion or suction on in situ chest drain?'. Altogether more than 200 papers were found using the reported search, of which 14 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Subcutaneous emphysema is usually a benign, self-limiting condition only requiring conservative management. Interventions are useful in the context of severe patient discomfort, respiratory distress or persistent air leak. In the absence of any comparative study, it is not possible to choose definitively between infraclavicular incisions, drain insertion and increasing suction on an in situ drain as the best method for managing severe subcutaneous emphysema. All the three techniques described have been shown to provide effective relief. Increasing suction on a chest tube already in situ provided rapid relief in patients developing SE following pulmonary resection. A retrospective study showed resolution in 66%, increasing to 98% in those who underwent video-assisted thoracic surgery with identification and closure of the leak. Insertion of a drain into the subcutaneous tissue also provided rapid sustained relief. Several studies aided drainage by using regular compressive massage. Infraclavicular incisions were also shown to provide rapid relief, but were noted to be more invasive and carried the potential for cosmetic defect. No major complications were illustrated. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  9. Aeolian and fluvial processes in dryland regions: the need for integrated studies

    Science.gov (United States)

    Belnap, Jayne; Munson, Seth M.; Field, Jason P.

    2011-01-01

    Aeolian and fluvial processes play a fundamental role in dryland regions of the world and have important environmental and ecological consequences from local to global scales. Although both processes operate over similar spatial and temporal scales and are likely strongly coupled in many dryland systems, aeolian and fluvial processes have traditionally been studied separately, making it difficult to assess their relative importance in drylands, as well as their potential for synergistic interaction. Land degradation by accelerated wind and water erosion is a major problem throughout the world's drylands, and although recent studies suggest that these processes likely interact across broad spatial and temporal scales to amplify the transport of soil resources from and within drylands, many researchers and land managers continue to view them as separate and unrelated processes. Here, we illustrate how aeolian and fluvial sediment transport is coupled at multiple spatial and temporal scales and highlight the need for these interrelated processes to be studied from a more integrated perspective that crosses traditional disciplinary boundaries. Special attention is given to how the growing threat of climate change and land-use disturbance will influence linkages between aeolian and fluvial processes in the future. We also present emerging directions for interdisciplinary needs within the aeolian and fluvial research communities that call for better integration across a broad range of traditional disciplines such as ecology, biogeochemistry, agronomy, and soil conservation.

  10. Floodplains: the forgotten and abused component of the fluvial system

    Directory of Open Access Journals (Sweden)

    Heritage George

    2016-01-01

    Full Text Available River restoration is strongly focussed on in-channel initiatives driven by fisheries interests and a continued desire for river stability. This contrasts greatly with the inherently mobile nature of watercourses. What is often overlooked is the fact that many rivers have developed floodplain units that would naturally operate as integrated functional systems, moderating the effects of extreme floods by distributing flow energy and sediment transport capacity through out of bank flooding. Floodplain utilisation for farming activities and landowner intransigence when it comes to acknowledging that the floodplain is part of the river system, has resulted in floodplains being the most degraded fluvial morphologic unit, both in terms of loss of form and function and sheer levels of spatial impact. The degradation has been facilitated by the failure of regulatory mechanisms to adequately acknowledge floodplain form and function. This is testament to the ‘inward looking’ thinking behind national assessment strategies. This paper reviews the state of floodplain systems drawing on quantitative data from England and Wales to argue for greater consideration of the floodplain in relation to river management. The database is poor and must be improved, however it does reveal significant loss of watercourse-floodplain connectivity linked to direct flood alleviation measures and also to altered flood frequency as a result of river downcutting following river engineering. These latter effects have persisted along many watercourses despite the historic nature of the engineering interventions and will continue to exacerbate the risk of flooding to downstream communities. We also present several examples of the local and wider values of reinstating floodplain form and function, demonstrating major ecological gains, improvement to downstream flood reduction, elevation of water quality status and reductions in overall fine sediment loss from farmland. A re

  11. Field Methods for the Study of Slope and Fluvial Processes

    Science.gov (United States)

    Leopold, Luna Bergere; Leopold, Luna Bergere

    1967-01-01

    In Belgium during the summer of 1966 the Commission on Slopes and the Commission on Applied Geomorphology of the International Geographical Union sponsored a joint symposium, with field excursions, and meetings of the two commissions. As a result of the conference and associated discussions, the participants expressed the view that it would be a contribution to scientific work relating to the subject area if the Commission on Applied Geomorphology could prepare a small manual describling the methods of field investigation being used by research scientists throughout the world in the study of various aspects of &lope development and fluvial processes. The Commission then assumed this responsibility and asked as many persons as were known to be. working on this subject to contribute whatever they wished in the way of descriptions of methods being employed.The purpose of the present manual is to show the variety of study methods now in use, to describe from the experience gained the limitations and advantages of different techniques, and to give pertinent detail which might be useful to other investigators. Some details that would be useful to know are not included in scientific publications, but in a manual on methods the details of how best t6 use a method has a place. Various persons have learned certain things which cannot be done, as well as some methods that are successful. It is our hope that comparison of methods tried will give the reader suggestions as to how a particular method might best be applied to his own circumstance.The manual does not purport to include methods used by all workers. In particular, it does not interfere with a more systematic treatment of the subject (1) or with various papers already published in the present journal. In fact we are sure that there are pertinent research methods that we do not know of and the Commission would be glad to receive additions and other ideas from those who find they have something to contribute. Also, the

  12. Biomarkers in Transit Reveal the Nature of Fluvial Integration

    Science.gov (United States)

    Ponton, C.; West, A.; Feakins, S. J.; Galy, V.

    2013-12-01

    The carbon and hydrogen isotopic composition of vascular plant leaf waxes are common proxies for hydrologic and vegetation change. Sedimentary archives off major river systems are prime targets for continental paleoclimate studies under the assumption that rivers integrate changes in terrestrial organic carbon (OC) composition over their drainage basin. However, the proportional contribution of sources within the basin (e.g. head waters vs. floodplain) and the transit times of OC through the fluvial system remain largely unknown. This lack of quantifiable information about the proportions and timescales of integration within large catchments poses a challenge for paleoclimate reconstructions. To examine the sources of terrestrial OC eroded and supplied to a river system and the spatial distribution of these sources, we use compound specific isotope analysis (i.e. δ13C, Δ14C, and δD) on plant-derived leaf waxes, filtered from large volumes of river water (20-200L) along a major river system. We selected the Kosñipata River that drains the western flank of the Andes in Peru, joins the Madre de Dios River across the Amazonian floodplain, and ultimately contributes to the Amazon River. Our study encompassed an elevation gradient of >4 km, in an almost entirely forested catchment. Precipitation δD values vary by >50‰ due to the isotopic effect of elevation, a feature we exploit to identify the sources of plant wax n-alkanoic acids transported by the river. We used the δD plant wax values from tributary rivers as source constrains and the main stem values as the integrated signal. In addition, compound specific radiocarbon on individual chain length n-alkanoic acids provide unprecedented detail on the integrated age of these compounds. Preliminary results have established that 1) most of the OC transport occurs in the wet season; 2) total carbon transport in the Madre de Dios is dominated by lowland sources because of the large floodplain area, but initial data

  13. Surgically induced astigmatism after 3.0 mm temporal and nasal clear corneal incisions in bilateral cataract surgery

    Directory of Open Access Journals (Sweden)

    Je Hwan Yoon

    2013-01-01

    Full Text Available Aims: To compare the corneal refractive changes induced after 3.0 mm temporal and nasal corneal incisions in bilateral cataract surgery. Materials and Methods: This prospective study comprised a consecutive case series of 60 eyes from 30 patients with bilateral phacoemulsification that were implanted with a 6.0 mm foldable intraocular lens through a 3.0 mm horizontal clear corneal incision (temporal in the right eyes, nasal in the left eyes. The outcome measures were surgically induced astigmatism (SIA and uncorrected visual acuity (UCVA 1 and 3 months, post-operatively. Results: At 1 month, the mean SIA was 0.81 diopter (D for the temporal incisions and 0.92 D for nasal incisions (P = 0.139. At 3 months, the mean SIA were 0.53 D for temporal incisions and 0.62 D for nasal incisions (P = 0.309. The UCVA was similar in the 2 incision groups before surgery, and at 1 and 3 months post-operatively. Conclusion: After bilateral cataract surgery using 3.0 mm temporal and nasal horizontal corneal incisions, the induced corneal astigmatic change was similar in both incision groups. Especially in Asian eyes, both temporal and nasal incisions (3.0 mm or less would be favorable for astigmatism-neutral cataract surgery.

  14. Does pilonidal abscess heal quicker with off-midline incision and drainage?

    Science.gov (United States)

    Webb, P M; Wysocki, A P

    2011-06-01

    No clinical trials have been done to guide the surgeon in the optimal technique of draining a pilonidal abscess. The aim of our study was to investigate whether the location of the incision influences wound healing. Electronic records from the surgical database at our 200-bed district general hospital were reviewed for operative technique (midline vs. lateral) for patients who underwent incision and drainage for acute pilonidal abscess between January 2003 and February 2010. These patients were admitted from the Emergency Department with a pilonidal abscess, underwent operative drainage, and returned for follow-up. The main outcome measure was wound healing time. Two hundred and forty-three pilonidal abscesses were drained, 134 with a lateral and 74 with a midline incision. All patients underwent simple longitudinal incision. No patient underwent de-roofing, marsupialisation, or closure. Forty-eight patients with midline drainage who returned for follow-up were matched for gender, age, and microbiology culture results with patients who underwent lateral drainage. Almost all were drained under general anesthesia with a median postoperative stay of 1 day. The overall length of follow-up was the same in both groups (P = 0.13). Abscesses that did not heal were followed-up for the same period of time irrespective of incision type (P = 0.48). Abscesses that healed after midline incision took approximately 3 weeks longer than those drained via a lateral incision (P = 0.02). Our study has limitations since it was a retrospective study that did not capture patients whose abscess drained spontaneously or were drained in the emergency department. Pilonidal abscess should be drained away from the midline.

  15. A study of incisive canal using a cone beam computed tomography

    International Nuclear Information System (INIS)

    Kim, Gyu Tae; Hwang, Eui Hwan; Lee, Sang Rae

    2004-01-01

    To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70 kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. The mean length of incisive canal was 15.87 mm ± 2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm ± 0.76 and 3.89 mm ± 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3 ± 6.96 and 117.45 ± 7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r 0.258). This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

  16. A study of incisive canal using a cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyu Tae; Hwang, Eui Hwan; Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    2004-03-15

    To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70 kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. The mean length of incisive canal was 15.87 mm {+-} 2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm {+-} 0.76 and 3.89 mm {+-} 1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3 {+-} 6.96 and 117.45 {+-} 7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r 0.258). This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

  17. Fluvial Channel Networks as Analogs for the Ridge-Forming Unit, Sinus Meridiani, Mars

    Science.gov (United States)

    Wilkinson, M. J.; du Bois, J. B.

    2010-01-01

    Fluvial models have been generally discounted as analogs for the younger layered rock units of Sinus Meridiani. A fluvial model based on the large fluvial fan provides a possibly close analog for various features of the sinuous ridges of the etched, ridge-forming unit (RFU) in particular. The close spacing of the RFU ridges, their apparently chaotic orientations, and their organization in dense networks all appear unlike classical stream channel patterns. However, drainage patterns on large fluvial fans low-angle, fluvial aggradational features, 100s of km long, documented worldwide by us provide parallels. Some large fan characteristics resemble those of classical floodplains, but many differences have been demonstrated. One major distinction relevant to the RFU is that channel landscapes of large fans can dominate large areas (1.2 million km2 in one S. American study area). We compare channel morphologies on large fans in the southern Sahara Desert with ridge patterns in Sinus Meridiani (fig 1). Stream channels are the dominant landform on large terrestrial fans: they may equate to the ubiquitous, sinuous, elongated ridges of the RFU that cover areas region wide. Networks of convergent/divergent and crossing channels may equate to similar features in the ridge networks. Downslope divergence is absent in channels of terrestrial upland erosional landscapes (fig. 1, left), whereas it is common to both large fans (fig. 1, center) and RFU ridge patterns (fig 1, right downslope defined as the regional NW slope of Sinus Meridiani). RFU ridge orientation, judged from those areas apparently devoid of impact crater control, is broadly parallel with the regional slope (arrow, fig. 1, right), as is mean orientation of major channels on large fans (arrow, fig. 1, center). High densities per unit area characterize fan channels and martian ridges reaching an order of magnitude higher than those in uplands just upstream of the terrestrial study areas fig. 1. In concert with

  18. Shaler: in situ analysis of a fluvial sedimentary deposit on Mars

    Science.gov (United States)

    Edgar, Lauren; Gupta, Sanjeev; Rubin, David M.; Lewis, Kevin W.; Kocurek, Gary A.; Anderson, Ryan; Bell, James F.; Dromart, Gilles; Edgett, Kenneth S.; Grotzinger, John P.; Hardgrove, Craig; Kah, Linda C.; LeVeille, Richard A.; Malin, Michael C.; Mangold, Nicholas; Milliken, Ralph E.; Minitti, Michelle; Palucis, Marisa C.; Rice, Melissa; Rowland, Scott K.; Schieber, Juergen; Stack, Kathryn M.; Sumner, Dawn Y.; Wiens, Roger C.; Williams, Rebecca M.E.; Williams, Amy J.

    2018-01-01

    This paper characterizes the detailed sedimentology of a fluvial sandbody on Mars for the first time, and interprets its depositional processes and palaeoenvironmental setting. Despite numerous orbital observations of fluvial landforms on the surface of Mars, ground-based characterization of the sedimentology of such fluvial deposits has not previously been possible. Results from the NASA Mars Science Laboratory Curiosity rover provide an opportunity to reconstruct at fine scale the sedimentary architecture and palaeomorphology of a fluvial environment on Mars. This work describes the grain size, texture, and sedimentary facies of the Shaler outcrop, reconstructs the bedding architecture, and analyses cross-stratification to determine palaeocurrents. On the basis of bedset geometry and inclination, grain-size distribution, and bedform migration direction, this study concludes that the Shaler outcrop likely records the accretion of a fluvial barform. The majority of the outcrop consists of large-scale trough cross-bedding of coarse sand and granules. Palaeocurrent analyses and bedform reconstruction indicate that the beds were deposited by bedforms that migrated towards the northeast, across the surface of a bar that migrated southeast. Stacked cosets of dune cross-bedding suggest aggradation of multiple bedforms, which provides evidence for short periods of sustained flow during Shaler deposition. However, local evidence for aeolian reworking and the presence of potential desiccation cracks within the outcrop suggests that fluvial deposition may have been intermittent. The uppermost strata at Shaler are distinct in terms of texture and chemistry, and are inferred to record deposition from a different sediment dispersal system with a contrasting provenance. The outcrop as a whole is a testament to the availability of liquid water on the surface of Mars in its early history.

  19. How well do the rosgen classification and associated "natural channel design" methods integrate and quantify fluvial processes and channel response?

    Science.gov (United States)

    Simon, A.; Doyle, M.; Kondolf, M.; Shields, F.D.; Rhoads, B.; Grant, G.; Fitzpatrick, F.; Juracek, K.; McPhillips, M.; MacBroom, J.

    2005-01-01

    Over the past 10 years the Rosgen classification system and its associated methods of "natural channel design" have become synonymous (to many without prior knowledge of the field) with the term "stream restoration" and the science of fluvial geomorphology. Since the mid 1990s, this classification approach has become widely, and perhaps dominantly adopted by governmental agencies, particularly those funding restoration projects. For example, in a request for proposals for the restoration of Trout Creek in Montana, the Natural Resources Conservation Service required "experience in the use and application of a stream classification system and its implementation." Similarly, classification systems have been used in evaluation guides for riparian areas and U.S. Forest Service management plans. Most notably, many highly trained geomorphologists and hydraulic engineers are often held suspect, or even thought incorrect, if their approach does not include reference to or application of a classification system. This, combined with the para-professional training provided by some involved in "natural channel design" empower individuals and groups with limited backgrounds in stream and watershed sciences to engineer wholesale re-patterning of stream reaches using 50-year old technology that was never intended for engineering design. At Level I, the Rosgen classification system consists of eight or nine major stream types, based on hydraulic-geometry relations and four other measures of channel shape to distinguish the dimensions of alluvial stream channels as a function of the bankfull stage. Six classes of the particle size of the boundary sediments are used to further sub-divide each of the major stream types, resulting in 48 or 54 stream types. Aside from the difficulty in identifying bankfull stage, particularly in incising channels, and the issue of sampling from two distinct populations (beds and banks) to classify the boundary sediments, the classification provides a

  20. Nove interpretacije fluvialnih sedimentov na krasu = New interpretations of fluvial sediments from the Kras

    Directory of Open Access Journals (Sweden)

    Andrej Mihevc

    2007-01-01

    Full Text Available Important unroofed caves with fluvial sediments from Divaški kras, Matarsko podoljePodgorski kras are presented. Extend of the phenomena and relation to the existingand karst surface and geomorphological meaning of them are described. Sedimentsthem were analysed and dated with different methods. The largest age of the sedimentfound in the unroofed cave excavated in Črnotiče quarry. In the cave wall fossil remainsstygobiont Marifugia cavatica were covered by 3.2-4.1 Ma old fluvial sediments.

  1. Fluvial sediment inputs to upland gravel bed rivers draining forested catchments: potential ecological impacts

    Directory of Open Access Journals (Sweden)

    S. D. Marks

    1997-01-01

    Full Text Available As identified by the detailed long-term monitoring networks at Plynlimon, increased sediment supply to upland fluvial systems is often associated with forestry land-use and practice. Literature is reviewed, in the light of recent results from Plynlimon sediment studies, to enable identification of the potential ecological impacts of fluvial particulate inputs to upland gravel bed rivers draining forested catchments similar to the headwaters of the River Severn. Both sediment transport and deposition can have significant impacts upon aquatic vertebrates, invertebrates and plants.

  2. GOEMORFOLOGIA FLUVIAL DA BACIA HIDROGRÁFICA DO RIO DE ONDAS

    Directory of Open Access Journals (Sweden)

    Ossifleres Silva Damasceno

    2011-10-01

    Full Text Available Os estudos de Geomorfologia Fluvial para analise de Bacias Hidrográficas vêm tendo nos últimos tempos grande importância, tanto para se conhecer as características de determinadas bacias como para se planejar o uso de tais recursos. Neste sentido, este trabalho foi efetuado no intuito de somar aos estudos anteriormente executados nessa bacia, levantando algumas características geomorfológicas, o uso e ocupação atual. Palavras-chaves: geomorfologia fluvial, hidrografia, agricultura irrigada.

  3. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains from fluvial deposits using optically stimulated luminescence

    International Nuclear Information System (INIS)

    Olley, J.M.; Caitcheon, G.G.; Roberts, R.G.

    1999-01-01

    We examine the causes of the asymmetric distributions of dose observed from measurements of the optically stimulated luminescence emitted by small aliquots of fluvial quartz, and deduce that the asymmetry arises as a result of samples being composed of a mix of mainly well bleached grains with grains that were effectively unbleached at the time of deposition. We demonstrate that the shapes of the dose distributions can be used to assess the likelihood that aliquots consist only of grains that were well-bleached at the time of deposition. The more asymmetric the distribution, the greater the probability that the aliquots with the lowest dose most closely represent the true burial dose. Single grains with differing doses are present in each of the samples examined, and the population with the lowest dose gives an optical age consistent with the expected burial age. This result implies that the beta-dose heterogeneity in these deposits is small, and that the effects of micro-dosimetric variations on optical dating of individual grains are not significant for these samples. We demonstrate that single-grain dating of fluvial material is possible and practicable using standard Risoe optical dating equipment, and we conclude that application of a new regenerative-dose protocol to single grains of quartz, using the lowest dose population to estimate the burial dose, is the best available means of obtaining reliable luminescence ages for heterogeneously bleached fluvial sediments

  4. Late Holocene lowland fluvial archives and geoarchaeology : Utrecht's case study of Rhine river abandonment under Roman and Medieval settlement

    NARCIS (Netherlands)

    van Dinter, M.; Cohen, K.M.; Hoek, W.Z.; Stouthamer, E.; Jansma, E.; Middelkoop, H.

    2017-01-01

    Fluvial lowlands have become attractive human settling areas all around the world over the last few millennia. Because rivers kept changing their course and networks due to avulsion, the sedimentary sequences in these areas are archives of both fluvial geomorphological and archaeological

  5. Force modeling for incisions into various tissues with MRF haptic master

    Science.gov (United States)

    Kim, Pyunghwa; Kim, Soomin; Park, Young-Dai; Choi, Seung-Bok

    2016-03-01

    This study proposes a new model to predict the reaction force that occurs in incisions during robot-assisted minimally invasive surgery. The reaction force is fed back to the manipulator by a magneto-rheological fluid (MRF) haptic master, which is featured by a bi-directional clutch actuator. The reaction force feedback provides similar sensations to laparotomy that cannot be provided by a conventional master for surgery. This advantage shortens the training period for robot-assisted minimally invasive surgery and can improve the accuracy of operations. The reaction force modeling of incisions can be utilized in a surgical simulator that provides a virtual reaction force. In this work, in order to model the reaction force during incisions, the energy aspect of the incision process is adopted and analyzed. Each mode of the incision process is classified by the tendency of the energy change, and modeled for realistic real-time application. The reaction force model uses actual reaction force information with three types of actual tissues: hard tissue, medium tissue, and soft tissue. This modeled force is realized by the MRF haptic master through an algorithm based on the position and velocity of a scalpel using two different control methods: an open-loop algorithm and a closed-loop algorithm. The reaction forces obtained from the proposed model are compared with a desired force in time domain.

  6. Panoramic radiographs underestimate extensions of the anterior loop and mandibular incisive canal

    Energy Technology Data Exchange (ETDEWEB)

    De Brito, Ana Caroline Ramos; Nejaim, Yuri; De Freitas, Deborah Queiroz [Dept. of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Sao Paulo (Brazil); De Oliveira Santos, Christiano [Dept. of Stomatology, Public Oral Health and Forensic Dentistry, School of Dentistry of Ribeirao Preto, University of Sao Paulo, Sao Paulo (Brazil)

    2016-09-15

    The purpose of this study was to detect the anterior loop of the mental nerve and the mandibular incisive canal in panoramic radiographs (PAN) and cone-beam computed tomography (CBCT) images, as well as to determine the anterior/mesial extension of these structures in panoramic and cross-sectional reconstructions using PAN and CBCT images. Images (both PAN and CBCT) from 90 patients were evaluated by 2 independent observers. Detection of the anterior loop and the incisive canal were compared between PAN and CBCT. The anterior/mesial extension of these structures was compared between PAN and both cross-sectional and panoramic CBCT reconstructions. In CBCT, the anterior loop and the incisive canal were observed in 7.7% and 24.4% of the hemimandibles, respectively. In PAN, the anterior loop and the incisive canal were detected in 15% and 5.5% of cases, respectively. PAN presented more difficulties in the visualization of structures. The anterior/mesial extensions ranged from 0.0 mm to 19.0 mm on CBCT. PAN underestimated the measurements by approximately 2.0 mm. CBCT appears to be a more reliable imaging modality than PAN for preoperative workups of the anterior mandible. Individual variations in the anterior/mesial extensions of the anterior loop of the mental nerve and the mandibular incisive canal mean that is not prudent to rely on a general safe zone for implant placement or bone surgery in the interforaminal region.

  7. Microincision versus small-incision coaxial cataract surgery using different power modes for hard nuclear cataract.

    Science.gov (United States)

    Kim, Eun Chul; Byun, Yong Soo; Kim, Man Soo

    2011-10-01

    To compare the efficacy of microincision and small-incision coaxial phacoemulsification in treating hard cataracts using different ultrasound power modes. Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, Catholic University of Korea, Seoul, Korea. Randomized clinical trial. Eyes with hard cataract were randomized to have an initial incision of 1.80 mm, 2.20 mm, or 2.75 mm. The eyes in each group were equally randomized to treatment with burst, pulse, or continuous mode. Ultrasound time (UST), mean cumulative dissipated energy (CDE), corrected distance visual acuity (CDVA), surgically induced corneal astigmatism, incisional and central corneal thickness (CCT), and endothelial cell counts were evaluated. The study enrolled 180 eyes, 60 in each group. Two months postoperatively, there were no statistically significant differences in UST, CDE, CDVA, CCT, or percentage endothelial cell loss between the 3 incision groups. The 2.75 mm incision induced more astigmatism at 2 months and less incisional corneal edema at 1 week than the 1.80 mm or 2.20 mm incision (Phard cataract. The intraoperative energy use and ocular damage was less with the pulse and burst modes than with the continuous mode. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. Single incision laparoscopic pancreas resection for pancreatic metastasis of renal cell carcinoma.

    Science.gov (United States)

    Barbaros, Umut; Sümer, Aziz; Demirel, Tugrul; Karakullukçu, Nazlı; Batman, Burçin; Içscan, Yalın; Sarıçam, Gülay; Serin, Kürçsat; Loh, Wei-Liang; Dinççağ, Ahmet; Mercan, Selçuk

    2010-01-01

    Transumbilical single incision laparoscopic surgery (SILS) offers excellent cosmetic results and may be associated with decreased postoperative pain, reduced need for analgesia, and thus accelerated recovery. Herein, we report the first transumbilical single incision laparoscopic pancreatectomy case in a patient who had renal cell cancer metastasis on her pancreatic corpus and tail. A 59-year-old female who had metastatic lesions on her pancreas underwent laparoscopic subtotal pancreatectomy through a 2-cm umbilical incision. Single incision pancreatectomy was performed with a special port (SILS port) and articulated equipment. The procedure lasted 330 minutes. Estimated blood loss was 100mL. No perioperative complications occurred. The patient was discharged on the seventh postoperative day with a low-volume (20mL/day) pancreatic fistula that ceased spontaneously. Pathology result of the specimen was renal cell cancer metastases. This is the first reported SILS pancreatectomy case, demonstrating that even advanced surgical procedures can be performed using the SILS technique in well-experienced centers. Transumbilical single incision laparoscopic pancreatectomy is feasible and can be performed safely in experienced centers. SILS may improve cosmetic results and allow accelerated recovery for patients even with malignancy requiring advanced laparoscopic interventions.

  9. Panoramic radiographs underestimate extensions of the anterior loop and mandibular incisive canal

    International Nuclear Information System (INIS)

    De Brito, Ana Caroline Ramos; Nejaim, Yuri; De Freitas, Deborah Queiroz; De Oliveira Santos, Christiano

    2016-01-01

    The purpose of this study was to detect the anterior loop of the mental nerve and the mandibular incisive canal in panoramic radiographs (PAN) and cone-beam computed tomography (CBCT) images, as well as to determine the anterior/mesial extension of these structures in panoramic and cross-sectional reconstructions using PAN and CBCT images. Images (both PAN and CBCT) from 90 patients were evaluated by 2 independent observers. Detection of the anterior loop and the incisive canal were compared between PAN and CBCT. The anterior/mesial extension of these structures was compared between PAN and both cross-sectional and panoramic CBCT reconstructions. In CBCT, the anterior loop and the incisive canal were observed in 7.7% and 24.4% of the hemimandibles, respectively. In PAN, the anterior loop and the incisive canal were detected in 15% and 5.5% of cases, respectively. PAN presented more difficulties in the visualization of structures. The anterior/mesial extensions ranged from 0.0 mm to 19.0 mm on CBCT. PAN underestimated the measurements by approximately 2.0 mm. CBCT appears to be a more reliable imaging modality than PAN for preoperative workups of the anterior mandible. Individual variations in the anterior/mesial extensions of the anterior loop of the mental nerve and the mandibular incisive canal mean that is not prudent to rely on a general safe zone for implant placement or bone surgery in the interforaminal region

  10. Incision and stress regulation in borderline personality disorder: neurobiological mechanisms of self-injurious behaviour.

    Science.gov (United States)

    Reitz, Sarah; Kluetsch, Rosemarie; Niedtfeld, Inga; Knorz, Teresa; Lis, Stefanie; Paret, Christian; Kirsch, Peter; Meyer-Lindenberg, Andreas; Treede, Rolf-Detlef; Baumgärtner, Ulf; Bohus, Martin; Schmahl, Christian

    2015-08-01

    Patients with borderline personality disorder frequently show non-suicidal self-injury (NSSI). In these patients, NSSI often serves to reduce high levels of stress. Investigation of neurobiological mechanisms of NSSI in borderline personality disorder. In total, 21 women with borderline personality disorder and 17 healthy controls underwent a stress induction, followed by either an incision into the forearm or a sham treatment. Afterwards participants underwent resting-state functional magnetic resonance imaging while aversive tension, heart rate and heart rate variability were assessed. We found a significant influence of incision on subjective and objective stress levels with a stronger decrease of aversive tension in the borderline personality disorder group following incision than sham. Amygdala activity decreased more and functional connectivity with superior frontal gyrus normalised after incision in the borderline personality disorder group. Decreased stress levels and amygdala activity after incision support the assumption of an influence of NSSI on emotion regulation in individuals with borderline personality disorder and aids in understanding why these patients use self-inflicted pain to reduce inner tension. © The Royal College of Psychiatrists 2015.

  11. Circumareolar incision-subdermal tunneling dissection for excision of multiple breast fibroadenomata

    Directory of Open Access Journals (Sweden)

    S O Agodirin

    2017-01-01

    Full Text Available Excision of multiple fibroadenomas (MF in separate breast quadrants presents difficulties of number and location of incision(s and extent of tissue dissection and may be associated with more complications and poorer cosmetic outcome. This is a report of excision of MF in multiple quadrants of the breast using a modification of subcutaneous dissection technique dubbed the circumareolar incision and subdermal tunneling (CAST dissection. After exposure of the superficial fascia with circumareolar incision, subdermal cone-wise dissection was made to allow mobilization of the segment bearing the lump(s. The lump(s were enucleated and removed. MF were removed from four breasts in three young unmarried females. The first patient had multiple adenomas removed from three quadrants of both breasts: 14 on the right and six on the left. The second patient had excision of three lumps in three separate quadrants, and the third patient had excision of two lumps in two separate quadrants. All patients had edema and bruising. One breast had wound infection and dehiscence. There were no skin necrosis, no nipple loss, and no breast distortion. All ensuing scars were camouflaged. CAST dissection was used for excision of MF in multiple quadrants of the breast with preservation of excellent cosmetic outcome of a single circumareolar incision.

  12. Uptake of gallium-67 citrate in clean surgical incisions after colorectal surgery

    International Nuclear Information System (INIS)

    Lin Wanyu; Wang Shyhjen; Tsai Shihchuan; Chao Tehsin

    2001-01-01

    Non-specific accumulation of gallium-67 citrate (gallium) in uncomplicated surgical incisions is not uncommon. It is important to know the normal pattern of gallium uptake at surgical incision sites in order to properly interpret the gallium scan when investigating possible wound infection in patients who have undergone abdominal surgery. We studied 42 patients without wound infection after colorectal surgery and performed gallium scans within 40 days after surgery. Patients were divided into three groups according to the interval between the operation and the scan. In group A (26 patients) gallium scan was performed within 7 days after surgery, in group B (8 patients) between 8 and 14 days after surgery, and in group C (8 patients) between 15 and 40 days after surgery. Our data showed that in group A, 61.5% had gallium accumulation at the surgical incision site. In group B, 50% had accumulation of gallium at the surgical incision site, while in group C only one patient (12.5%) showed gallium uptake. It is concluded that the incidence of increased gallium uptake at clean surgical incision sites is high after colorectal surgery. Nuclear medicine physicians should bear in mind the high incidence of non-specific gallium uptake at such sites during the interpretation of possible wound infection in patients after colorectal surgery. (orig.)

  13. Force modeling for incisions into various tissues with MRF haptic master

    International Nuclear Information System (INIS)

    Kim, Pyunghwa; Kim, Soomin; Park, Young-Dai; Choi, Seung-Bok

    2016-01-01

    This study proposes a new model to predict the reaction force that occurs in incisions during robot-assisted minimally invasive surgery. The reaction force is fed back to the manipulator by a magneto-rheological fluid (MRF) haptic master, which is featured by a bi-directional clutch actuator. The reaction force feedback provides similar sensations to laparotomy that cannot be provided by a conventional master for surgery. This advantage shortens the training period for robot-assisted minimally invasive surgery and can improve the accuracy of operations. The reaction force modeling of incisions can be utilized in a surgical simulator that provides a virtual reaction force. In this work, in order to model the reaction force during incisions, the energy aspect of the incision process is adopted and analyzed. Each mode of the incision process is classified by the tendency of the energy change, and modeled for realistic real-time application. The reaction force model uses actual reaction force information with three types of actual tissues: hard tissue, medium tissue, and soft tissue. This modeled force is realized by the MRF haptic master through an algorithm based on the position and velocity of a scalpel using two different control methods: an open-loop algorithm and a closed-loop algorithm. The reaction forces obtained from the proposed model are compared with a desired force in time domain. (paper)

  14. Steady incision of Grand Canyon at the million year timeframe: a case for mantle-driven differential uplift

    Science.gov (United States)

    Crow, Ryan S.; Karl Karlstrom,; Laura Crossey,; Richard Young,; Michael Ort,; Yemane Asmerom,; Victor Polyak,; Andrew Darling,

    2014-01-01

    The Grand Canyon region provides an excellent laboratory to examine the interplay between river incision, magmatism, and the geomorphic and tectonic processes that shape landscapes. Here we apply U-series, Ar–Ar, and cosmogenic burial dating of river terraces to examine spatial variations in incision rates along the 445 km length of the Colorado River through Grand Canyon. We also analyze strath terrace sequences that extend to heights of several hundred meters above the river, and integrate these with speleothem constrained maximum incision rates in several reaches to examine any temporal incision variations at the million-year time frame. This new high-resolution geochronology shows temporally steady long-term incision in any given reach of Grand Canyon but significant variations along its length from 160 m/Ma in the east to 101 m/Ma in the west. Spatial and temporal patterns of incision, and the long timescale of steady incision rule out models where geomorphic controls such as climate oscillations, bedrock strength, sediment load effects, or isostatic response to differential denudation are the first order drivers of canyon incision. The incision pattern is best explained by a model of Neogene and ongoing epeirogenic uplift due to an eastward propagating zone of increased upper mantle buoyancy that we infer from propagation of Neogene basaltic volcanism and a strong lateral gradient in modern upper mantle seismic structure.

  15. Oral subcutaneous midline leiomyomatous hamartoma presenting as congenital incisive papilla overgrowth in a toddler

    Directory of Open Access Journals (Sweden)

    Ashish Loomba

    2017-01-01

    Full Text Available Congenital soft-tissue tumors of oral cavity are mostly hyperplastic and benign in nature. This article presents an unusual case of congenital subcutaneous hamartoma of incisive papilla in a 2-year-old female child causing feeding and breathing difficulty. Total excisional biopsy was done under local anesthesia. Histopathology of tissue in reticulin-stained slide showed the presence of immature muscle fibers whereas Masson's trichrome stain revealed collagen fibers and smooth muscles confirming the diagnosis of oral midline subcutaneous smooth muscle (leiomyomatous hamartoma of incisive papilla. It is important for dental professionals to be aware of this oral lesion present from birth mimicking overgrowth of incisive papilla, by its presentation, differential diagnosis, histopathology, and management.

  16. Incision of the heart during meat inspection of fattening pigs - A risk-profile approach.

    Science.gov (United States)

    Leps, J; Fries, R

    2009-01-01

    Meat inspection in the EU is based on Regulation (EC) 854/2004. Accordingly a risk based meat inspection should be implemented. In this paper, the incision of the heart in pig meat inspection is discussed with respect to efficacy. The incision especially can reveal the presence of endocarditis. Here, Erysipelothrixrhusiopathiae (E. rhusiopathiae) and/or Streptococcussuis (S. suis) are of particular concern. Both agents are regarded to be zoonotic agents. There is some evidence for infection of humans via an alimentary pathway. Hence, the occurrence of E. rhusiopathiae and S. suis is a concern of public health (PH) as well as veterinary public health (VPH). However, other measures, including on-farm disease prevention and diagnosis, seem to be more important for food safety. It is concluded that the incision and inspection of the heart is not justifiable with respect to PH aspects.

  17. Incisiones verticales en SARPE Vertical incisions in SARPE

    OpenAIRE

    J. Gonzalez Lagunas; J.A. Hueto Madrid; G. Raspall Martín

    2005-01-01

    La expansión rápida de paladar asistida quirúrgicamente (SARPE) es una de las opciones terapeuticas de los transtornos transversales del maxilar superior. Presentamos nuestra experiencia inicial con una variante técnica consistente en una corticotomía de la pared lateral del maxilar combinada con una osteotomía palatina media transincisal, y efectuadas a través de tres pequeñas incisiones verticales.Surgically assisted rapid palatal expansion (SARPE) is one of the therapeutic options for the ...

  18. Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study.

    Science.gov (United States)

    Sekundo, Walter; Kunert, Kathleen S; Blum, Marcus

    2011-03-01

    This 6 month prospective multi-centre study evaluated the feasibility of performing myopic femtosecond lenticule extraction (FLEx) through a small incision using the small incision lenticule extraction (SMILE) procedure. Prospective, non-randomised clinical trial. PARTICIPANTS; Ninety-one eyes of 48 patients with myopia with and without astigmatism completed the final 6 month follow-up. The patients' mean age was 35.3 years. Their preoperative mean spherical equivalent (SE) was −4.75±1.56 D. A refractive lenticule of intrastromal corneal tissue was cut utilising a prototype of the Carl Zeiss Meditec AG VisuMax femtosecond laser system. Simultaneously two opposite small ‘pocket’ incisions were created by the laser system. Thereafter, the lenticule was manually dissected with a spatula and removed through one of incisions using modified McPherson forceps. Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) after 6 months, objective and manifest refraction as well as slit-lamp examination, side effects and a questionnaire. Six months postoperatively the mean SE was −0.01 D±0.49 D. Most treated eyes (95.6%) were within ±1.0 D, and 80.2% were within ±0.5 D of intended correction. Of the eyes treated, 83.5% had an UCVA of 1.0 (20/20) or better, 53% remained unchanged, 32.3% gained one line, 3.3% gained two lines of BSCVA, 8.8% lost one line and 1.1% lost ≥2 lines of BSCVA. When answering a standardised questionnaire, 93.3% of patients were satisfied with the results obtained and would undergo the procedure again. SMILE is a promising new flapless minimally invasive refractive procedure to correct myopia.

  19. Results of radiocarbon dating of Holocene fluvial sediments from Northeastern Bohemia

    International Nuclear Information System (INIS)

    Silar, J.; Zeman, A.

    1989-01-01

    Samples of wood and charcoal from the latest Holocene fluvial sediments under the lowest surface of alluvial plains were dated by radiocarbon in order to check paleomagnetic data at four sites in northeastern Bohemia. The results are presented as funcorrected 14 C ages and dendrochronologically corrected ages. Two samples were recent. 4 figs., 1 tab., 3 refs

  20. The impact of disturbance on the dynamics of fluvial processes in mountain landscapes

    Czech Academy of Sciences Publication Activity Database

    Langhammer, J.; Hartvich, Filip; Kliment, Z.; Jeníček, M.; Bernsteinová (Kaiglová), J.; Vlček, L.; Su, Y.; Štych, P.; Miřijovský, J.

    2015-01-01

    Roč. 21, č. 1 (2015), s. 105-116 ISSN 1211-7420 Institutional support: RVO:67985891 Keywords : runoff * fluvial dynamics * forest disturbance * climate change * Bohemian Forest Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://www.npsumava.cz/gallery/31/9345-sg_21_1_langhammeretal.pdf

  1. Mechanosensory based orienting behaviors in fluvial and lacustrine populations of mottled sculpin (Cottus bairdi)

    Science.gov (United States)

    Sheryl Coombs; Gary D. Grossman

    2006-01-01

    We compared prey-orienting and rheotactic behaviors in a fluvial (Coweeta Creek) and lacustrine (Lake Michigan) population of mottled sculpin. Blinded sculpin from both populations exhibited unconditioned, mechanosensory based rheotaxis to low velocity flows. Whereas Lake Michigan sculpin generally showed increasing levels of positive rheotaxis to increasing velocities...

  2. Volcanogenic Fluvial-Lacustrine Environments in Iceland and Their Utility for Identifying Past Habitability on Mars

    Directory of Open Access Journals (Sweden)

    Claire Cousins

    2015-02-01

    Full Text Available The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite, and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides. This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

  3. Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

    Science.gov (United States)

    Cousins, Claire

    2015-02-16

    The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

  4. Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks

    NARCIS (Netherlands)

    Mann, Paul J.; Eglinton, Timothy I.; McIntyre, Cameron P.; Zimov, Nikita; Davydova, Anna; Vonk, Jorien E.; Holmes, Robert M.; Spencer, Robert G M

    2015-01-01

    Northern high-latitude rivers are major conduits of carbon from land to coastal seas and the Arctic Ocean. Arctic warming is promoting terrestrial permafrost thaw and shifting hydrologic flowpaths, leading to fluvial mobilization of ancient carbon stores. Here we describe 14 C and 13 C

  5. Reservoir architecture and tough gas reservoir potential of fluvial crevasse-splay deposits

    NARCIS (Netherlands)

    Van Toorenenburg, K.A.; Donselaar, M.E.; Weltje, G.J.

    2015-01-01

    Unconventional tough gas reservoirs in low-net-to-gross fluvial stratigraphic intervals may constitute a secondary source of fossil energy to prolong the gas supply in the future. To date, however, production from these thin-bedded, fine-grained reservoirs has been hampered by the economic risks

  6. The Amazonian Craton and its influence on past fluvial systems (Mesozoic-Cenozoic, Amazonia)

    NARCIS (Netherlands)

    Hoorn, C.; Roddaz, M.; Dino, R.; Soares, E.; Uba, C.; Ochoa-Lozano, D.; Mapes, R.; Hoorn, C.; Wesselingh, F.P.

    2010-01-01

    The Amazonian Craton is an old geological feature of Archaean/Proterozoic age that has determined the character of fluvial systems in Amazonia throughout most of its past. This situation radically changed during the Cenozoic, when uplift of the Andes reshaped the relief and drainage patterns of

  7. Study on detailed geological modelling for fluvial sandstone reservoir in Daqing oil field

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hanqing; Fu Zhiguo; Lu Xiaoguang [Institute of Petroleum Exploration and Development, Daqing (China)

    1997-08-01

    Guided by the sedimentation theory and knowledge of modern and ancient fluvial deposition and utilizing the abundant information of sedimentary series, microfacies type and petrophysical parameters from well logging curves of close spaced thousands of wells located in a large area. A new method for establishing detailed sedimentation and permeability distribution models for fluvial reservoirs have been developed successfully. This study aimed at the geometry and internal architecture of sandbodies, in accordance to their hierarchical levels of heterogeneity and building up sedimentation and permeability distribution models of fluvial reservoirs, describing the reservoir heterogeneity on the light of the river sedimentary rules. The results and methods obtained in outcrop and modem sedimentation studies have successfully supported the study. Taking advantage of this method, the major producing layers (PI{sub 1-2}), which have been considered as heterogeneous and thick fluvial reservoirs extending widely in lateral are researched in detail. These layers are subdivided into single sedimentary units vertically and the microfacies are identified horizontally. Furthermore, a complex system is recognized according to their hierarchical levels from large to small, meander belt, single channel sandbody, meander scroll, point bar, and lateral accretion bodies of point bar. The achieved results improved the description of areal distribution of point bar sandbodies, provide an accurate and detailed framework model for establishing high resolution predicting model. By using geostatistic technique, it also plays an important role in searching for enriched zone of residual oil distribution.

  8. Model Projections of Future Fluvial Sediment Delivery to Major Deltas Under Environmental Change

    Science.gov (United States)

    Darby, S. E.; Dunn, F.; Nicholls, R. J.; Cohen, S.; Zarfl, C.

    2017-12-01

    Deltas are important hot spots for climate change impacts on which over half a billion people live worldwide. Most of the world's deltas are sinking as a result of natural and anthropogenic subsidence and due to eustatic sea level rise. The ability to predict rates of delta aggradation is therefore critical to assessments of the extent to which sedimentation can potentially offset sea level rise, but our ability to make such predictions is severely hindered by a lack of insight into future trends of the fluvial sediment load supplied to their deltas by feeder watersheds. To address this gap we investigate fluvial sediment fluxes under future environmental change for a selection (47) of the world's major river deltas. Specifically, we employed the numerical model WBMsed to project future variations in mean annual fluvial sediment loads under a range of environmental change scenarios that account for changes in climate, socio-economics and dam construction. Our projections indicate a clear decrease (by 34 to 41% on average, depending on the specific scenario) in future fluvial sediment supply to most of the 47 deltas. These reductions in sediment delivery are driven primarily by anthropogenic disturbances, with reservoir construction being the most influential factor globally. Our results indicate the importance of developing new management strategies for reservoir construction and operation.

  9. On the connectivity anisotropy in fluvial Hot Sedimentary Aquifers and its influence on geothermal doublet performance

    DEFF Research Database (Denmark)

    Willems, Cees J.L.; Nick, Hamid; Donselaar, Marinus E.

    2017-01-01

    This study finds that the geothermal doublet layout with respect to the paleo flow direction in fluvial sedimentary reservoirs could significantly affect pump energy losses. These losses can be reduced by up to 10% if a doublet well pair is oriented parallel to the paleo flow trend compared...

  10. Transport and redistribution of Chernobyl fallout radionuclides by fluvial processes: some preliminary evidence

    International Nuclear Information System (INIS)

    Walling, D.E.; Bradley, S.B.

    1988-01-01

    Several measurements of 137 Cs concentrations in suspended sediment transported by the River Severn during the post-Chernobyl period and in recent channel and floodplain deposits along the river emphasise the potential significance of fluvial processes in the transport and concentration of fallout radionuclides. (author)

  11. Human impact on fluvial regimes and sediment flux during the Holocene: review and future research agenda

    NARCIS (Netherlands)

    Hoffmann, T.; Thorndycraft, V.R.; Brown, A.G.; Coulthard, T.J.; Damnati, B.; Kale, V.S.; Middelkoop, H.; Notebaert, B.; Walling, D.E.

    2010-01-01

    There is a long history of human–riverine interactions throughout the period of agriculture that in some regions of the world started several thousand years ago. These interactions have altered rivers to human dominated systems with often negative impacts on fluvial environments. To achieve a good

  12. Re-evaluating luminescence burial doses and bleaching of fluvial deposits using Bayesian computational statistics.

    NARCIS (Netherlands)

    Cunningham, A.C.; Wallinga, J.; Versendaal, Alice; Makaske, A.; Middelkoop, H.; Hobo, N.

    2015-01-01

    The optically stimulated luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  13. Re-evaluating luminescence burial doses and bleaching of fluvial deposits using Bayesian computational statistics

    NARCIS (Netherlands)

    Cunningham, A. C.; Wallinga, J.; Hobo, N.; Versendaal, A. J.; Makaske, B.; Middelkoop, H.

    2015-01-01

    The optically stimulated luminescence (OSL) signal from fluvial sediment often contains a remnant from the previous deposition cycle, leading to a partially bleached equivalent-dose distribution. Although identification of the burial dose is of primary concern, the degree of bleaching could

  14. Phosphorus and nitrogen loading depths in fluvial sediments following manure spill simulations

    Science.gov (United States)

    Manure spills that enter streams can devastate the aquatic ecosystem. The depth of nitrogen (N) and phosphorus (P) loading in fluvial sediments following a manure spill have not been documented. Thus, the objectives of this study were (i) to determine the depth of N and P contamination as a result o...

  15. Depositional record of an avulsive fluvial system controlled by peat compaction (Neogene, Most Basin, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Rajchl, M.; Uličný, David

    2005-01-01

    Roč. 52, č. 3 (2005), s. 601-625 ISSN 0037-0746 R&D Projects: GA ČR GA205/01/0629 Institutional research plan: CEZ:AV0Z30120515 Keywords : avulsion * Eger Graben * fluvial channels Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.876, year: 2005

  16. Fluvial system response to Late Devensian (Weichselian) aridity, Baston, Lincolnshire, England

    Science.gov (United States)

    Briant, Rebecca M.; Coope, G. Russell; Preece, Richard C.; Keen, David H.; Boreham, Steve; Griffiths, Huw I.; Seddon, Mary B.; Gibbard, Philip L.

    2004-07-01

    Little is known about the impact of Late Devensian (Weichselian) aridity on lowland British landscapes, largely because they lack the widespread coversand deposits of the adjacent continent. The concentration of large interformational ice-wedge casts in the upper part of many Devensian fluvial sequences suggests that fluvial activity may have decreased considerably during this time. The development of optically stimulated luminescence (OSL) dating enables this period of ice-wedge cast formation to be constrained for the first time in eastern England, where a marked horizon of ice-wedge casts is found between two distinctive dateable facies associations. Contrasts between this horizon and adjacent sediments show clear changes in environment and fluvial system behaviour in response to changing water supply, in line with palaeontological evidence. In addition to providing chronological control on the period of ice-wedge formation, the study shows good agreement of the radiocarbon and OSL dating techniques during the Middle and Late Devensian, with direct comparison of these techniques beyond 15 000 yr for the first time in Britain. It is suggested that aridity during the Late Devensian forced a significant decrease in fluvial activity compared with preceding and following periods, initiating a system with low peak flows and widespread permafrost development. Copyright

  17. Modelling the impact of regional uplift and local tectonics on fluvial terrace preservation.

    NARCIS (Netherlands)

    Viveen, W.; Schoorl, J.M.; Veldkamp, A.; Balen, van R.T.

    2014-01-01

    A terrace formation model (TERRACE) combined with a longitudinal river profile model (FLUVER) was used to simulate fluvial terrace formation and preservation in the northwest Iberian lower Miño River basin under the influence of three tectonic conditions; namely regional vertical uplift, local basin

  18. Revisiting geochemical methods of distinguishing natural concentrations and pollution by risk elements in fluvial sediments

    Czech Academy of Sciences Publication Activity Database

    Matys Grygar, Tomáš; Popelka, J.

    2016-01-01

    Roč. 170, NOV (2016), s. 39-57 ISSN 0375-6742 R&D Projects: GA ČR(CZ) GA15-00340S Institutional support: RVO:61388980 Keywords : Enrichment * Fluvial sediments * Heavy metals Subject RIV: DD - Geochemistry Impact factor: 2.464, year: 2016

  19. Middle Moscovian climate of eastern equatorial Pangea recorded in paleosols and fluvial architecture

    Czech Academy of Sciences Publication Activity Database

    Opluštil, S.; Lojka, R.; Rosenau, N.A.; Strnad, L.; Sýkorová, Ivana

    2015-01-01

    Roč. 440, DEC (2015), s. 328-352 ISSN 0031-0182 Institutional support: RVO:67985891 Keywords : Carboniferous paleoclimate * fluvial architectures * paleosols * geochemistry Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.525, year: 2015 http://www.sciencedirect.com/science/article/pii/S0031018215004939

  20. Variables and potential models for the bleaching of luminescence signals in fluvial environments

    Science.gov (United States)

    Gray, Harrison J.; Mahan, Shannon

    2015-01-01

    Luminescence dating of fluvial sediments rests on the assumption that sufficient sunlight is available to remove a previously obtained signal in a process deemed bleaching. However, luminescence signals obtained from sediment in the active channels of rivers often contain residual signals. This paper explores and attempts to build theoretical models for the bleaching of luminescence signals in fluvial settings. We present two models, one for sediment transported in an episodic manner, such as flood-driven washes in arid environments, and one for sediment transported in a continuous manner, such as in large continental scale rivers. The episodic flow model assumes that the majority of sediment is bleached while exposed to sunlight at the near surface between flood events and predicts a power-law decay in luminescence signal with downstream transport distance. The continuous flow model is developed by combining the Beer–Lambert law for the attenuation of light through a water column with a general-order kinetics equation to produce an equation with the form of a double negative exponential. The inflection point of this equation is compared with the sediment concentration from a Rouse profile to derive a non-dimensional number capable of assessing the likely extent of bleaching for a given set of luminescence and fluvial parameters. Although these models are theoretically based and not yet necessarily applicable to real-world fluvial systems, we introduce these ideas to stimulate discussion and encourage the development of comprehensive bleaching models with predictive power.

  1. Phytolith analysis in fluvial quaternary sediment (San Salvador and Palmar formation) Uruguay river and Argentina eastern

    International Nuclear Information System (INIS)

    Patterer, N.; Passeggi, E.; Zucol, A.; Brea, M.; Krohling, D.

    2012-01-01

    This work is about two microfossils fluvial units deposited by the Uruguay river during the Quaternary. These are San Salvador and Palmar formation (Plio-Pleistocene - Upper Pleistocene).The Palmar formation is a band of 4-15 km along the right bank of the Uruguay river outcropping from the eastern provinces of Corrientes and Entre Rios, to Concepcion del Uruguay

  2. Fluvial response to Holocene volcanic damming and breaching in the Gediz and Geren rivers, western Turkey

    NARCIS (Netherlands)

    van Gorp, W.; Veldkamp, A.; Temme, A.J.A.M.; Maddy, D; Demir, T.; Schriek van der, T.; Reimann, T.; Wallinga, J.; Wijbrans, J.R.; Schoorl, J.M.

    2013-01-01

    This study discusses the complex late Holocene evolution of the Gediz River north of Kula, western Turkey, when a basaltic lava flow dammed and filled this river valley. Age control was obtained using established and novel feldspar luminescence techniques on fluvial sands below and on top of the

  3. Buried late Pleistocene fluvial channels on the inner continental shelf off Vengurla, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    SubbaRaju, L.V.; Krishna, K.S.; Chaubey, A.K.

    with sediments. Cross sectional dimensions between 15 to 100 m width and 2 to 6 m depth suggest a fluvial origin of the channels. These buried channels appear to mark former positions of rivers flowing from the nearby coast and debouching into the Arabian Sea...

  4. "The Waters of Meridiani" - Further Support for a Fluvial Interpretation of the Ridged, Layered Units

    Science.gov (United States)

    Wilkinson, Justin; Kreslavsky, Misha

    2009-01-01

    A relatively unknown terrestrial fluvial environment, the mesoscale megafan, provides analogs for various Martian landscapes, including the etched unit (etched unit, Unite E of Arvidson et al., 2003; ridge-forming unit R of Edgett, 2005) of the Sinus Meridiani region on Mars. A global survey of Earth shows that megafans are very large partial cones of dominantly fluvial sediment with radii on the order of hundreds of km, and very low slopes. Responsible fluvial processes are sufficiently different from those of classical arid alluvial fans and deltas that it is useful to class megafans as separate features. The megafan model calls into question two commonly held ideas. 1. Earth examples prove that topographic basins per se are unnecessary for the accumulation of large sedimentary bodies. 2. River channels are by no means restricted to valleys (Meridiani sediments are termed a "valley-ed volume" of Edgett). These perspectives reveal unexpected parallels with features at Meridiani-several channel-like features that are widespread, mostly as ridges inverted by eolian erosion; channel networks covering thousands of sq km, especially on intercrater plains; and regional relationships of sediment bodies situated immediately downstream of highland masses. These all suggest that fluvial explanations are at least part of the Meridiani story.

  5. Impact of selective pituitary gland incision or resection on hormonal function after adenoma or cyst resection.

    Science.gov (United States)

    Barkhoudarian, Garni; Cutler, Aaron R; Yost, Sam; Lobo, Bjorn; Eisenberg, Amalia; Kelly, Daniel F

    2015-12-01

    With the resection of pituitary lesions, the anterior pituitary gland often obstructs transsphenoidal access to the lesion. In such cases, a gland incision and/or partial gland resection may be required to obtain adequate exposure. We investigate this technique and determine the associated risk of post-operative hypopituitarism. All patients who underwent surgical resection of a pituitary adenoma or Rathke cleft cyst (RCC) between July 2007 and January 2013 were analyzed for pre- and post-operative hormone function. The cohort of patients with gland incision/resection were compared to a case-matched control cohort of pituitary surgery patients. Total hypophysectomy patients were excluded from outcome analysis. Of 372 operations over this period, an anterior pituitary gland incision or partial gland resection was performed in 79 cases (21.2 %). These include 53 gland incisions, 12 partial hemi-hypophysectomies and 14 resections of thinned/attenuated anterior gland. Diagnoses included 64 adenomas and 15 RCCs. New permanent hypopituitarism occurred in three patients (3.8 %), including permanent DI (3) and growth hormone deficiency (1). There was no significant difference in the rate of worsening gland dysfunction nor gain of function. Compared to a control cohort, there was a significantly lower incidence of transient DI (1.25 vs. 11.1 %, p = 0.009) but no significant difference in permanent DI (3.8 vs. 4.0 %) in the gland incision group. Selective gland incisions and gland resections were performed in over 20 % of our cases. This technique appears to minimize traction on compressed normal pituitary gland during removal of large lesions and facilitates better visualization and removal of cysts, microadenomas and macroadenomas.

  6. Efficiency of soft tissue incision with a novel 445-nm semiconductor laser.

    Science.gov (United States)

    Braun, Andreas; Kettner, Moritz; Berthold, Michael; Wenzler, Johannes-Simon; Heymann, Paul Günther Baptist; Frankenberger, Roland

    2018-01-01

    Using a 445-nm semiconductor laser for tissue incision, an effective cut is expected due to the special absorption properties of blue laser light in soft tissues. The aim of the present study was the histological evaluation of tissue samples after incision with a 445-nm diode laser. Forty soft tissue specimens were obtained from pork oral mucosa and mounted on a motorized linear translation stage. The handpiece of a high-frequency surgery device, a 970-nm semiconductor laser, and a 445-nm semiconductor laser were connected to the slide, allowing a constant linear movement (2 mm/s) and the same distance of the working tip to the soft tissue's surface. Four incisions were made each: (I) 970-nm laser with conditioned fiber tip, contact mode at 3-W cw; (II-III): 445-nm laser with non-conditioned fiber tip, contact mode at 2-W cw, and non-contact mode (1 mm) at 2 W; and (IV): high-frequency surgery device with straight working tip, 90° angulation, contact mode at 50 W. Histological analysis was performed after H&E staining of the embedded specimens at 35-fold magnification. The comparison of the incision depths showed a significant difference depending on the laser wavelength and the selected laser parameters. The highest incision depth was achieved with the 445-nm laser contact mode (median depth 0.61 mm, min 0.26, max 1.17, interquartile range 0.58) (p laser, a higher cutting efficiency can be expected when compared with a 970-nm diode laser and high-frequency surgery. Even the 445-nm laser application in non-contact mode shows clinically acceptable incision depths without signs of extensive soft tissue denaturation.

  7. The effect of kidney morcellation on operative time, incision complications, and postoperative analgesia after laparoscopic nephrectomy

    Directory of Open Access Journals (Sweden)

    Affonso H. Camargo

    2006-06-01

    Full Text Available INTRODUCTION: Compare the outcomes between kidney morcellation and two types of open specimen extraction incisions, several covariates need to be taken into consideration that have not yet been studied. MATERIALS AND METHODS: We retrospectively reviewed 153 consecutive patients who underwent laparoscopic nephrectomy at our institution, 107 who underwent specimen morcellation and 46 with intact specimen removal, either those with connected port sites with a muscle-cutting incision and those with a remote, muscle-splitting incision. Operative time, postoperative analgesia requirements, and incisional complications were evaluated using univariate and multivariate analysis, comparing variables such as patient age, gender, body mass index (BMI, laterality, benign versus cancerous renal conditions, estimated blood loss, specimen weight, overall complications, and length of stay. RESULTS: There was no significant difference for operative time between the 2 treatment groups (p = 0.65. Incision related complications occurred in 2 patients (4.4% from the intact specimen group but none in the morcellation group (p = 0.03. Overall narcotic requirement was lower in patients with morcellated (41 mg compared to intact specimen retrieval (66 mg on univariate (p = 0.03 and multivariate analysis (p = 0.049. Upon further stratification, however, there was no significant difference in mean narcotic requirement between the morcellation and muscle-splitting incision subgroup (p = 0.14. CONCLUSION: Morcellation does not extend operative time, and is associated with significantly less postoperative pain compared to intact specimen retrieval overall, although this is not statistically significant if a remote, muscle-splitting incision is made. Morcellation markedly reduces the risk of incisional-related complications.

  8. Cutting electrocautery versus scalpel for surgical incisions: a systematic review and meta-analysis.

    Science.gov (United States)

    Ismail, Ammar; Abushouk, Abdelrahman Ibrahim; Elmaraezy, Ahmed; Menshawy, Amr; Menshawy, Esraa; Ismail, Mahmoud; Samir, Esraa; Khaled, Anas; Zakarya, Hagar; El-Tonoby, Abdelrahman; Ghanem, Esraa

    2017-12-01

    Although cutting electrocautery can be superior to the scalpel in reducing blood loss and incisional time, several reports associated electrocautery with higher rates of wound infection, impaired healing, and worse cosmesis. We performed this systematic review and meta-analysis to compare cutting electrocautery versus scalpel for surgical incisions. We conducted a computerized literature search of five electronic databases and included all published original studies comparing cutting electrocautery and scalpel surgical incisions. Relevant data were extracted from eligible studies and pooled as odds ratios (ORs) or standardized mean difference (SMD) values in a meta-analysis model, using RevMan and Comprehensive Meta-analysis software. Forty-one studies (36 randomized trials, four observational, and one quasirandom study) were included in the pooled analysis (6422 participants). Compared with the scalpel incision, cutting electrocautery resulted in significantly less blood loss (SMD = -1.16, 95% CI [-1.60 to -0.72]), shorter incisional (SMD = -0.63, 95% CI [-0.96 to -0.29]) and operative times (SMD = -0.59, 95% CI [-1.12 to -0.05]), and lower pain scores (SMD = -0.91, 95% CI [-1.27 to -0.55]) with no significant differences in terms of wound infection rates (OR = 0.92, 95% CI [0.74-1.15]) or overall subjective scar score (SMD = -0.49, 95% CI [-1.72 to 0.75]). Surgical incision using electrocautery can be quicker with less blood loss and postoperative pain scores than the scalpel incision. No statistically significant difference was found between both techniques in terms of postoperative wound complications, hospital stay duration, and wound cosmetic characteristics. Therefore, we recommend routine use of cutting electrocautery for surgical incisions. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Environmental changes in the central Po Plain (northern Italy) due to fluvial modifications and anthropogenic activities

    Science.gov (United States)

    Marchetti, Mauro

    2002-05-01

    The fluvial environment of the central Po Plain, the largest plain in Italy, is discussed in this paper. Bounded by the mountain chains of the Alps and the Apennines, this plain is a link between the Mediterranean environment and the cultural and continental influences of both western and eastern Europe. In the past decades, economic development has been responsible for many changes in the fluvial environment of the area. This paper discusses the changes in fluvial dynamics that started from Late Pleistocene and Early Holocene due to distinct climatic changes. The discussion is based on geomorphological, pedological, and archaeological evidences and radiocarbon dating. In the northern foothills, Late Pleistocene palaeochannels indicate several cases of underfit streams among the northern tributaries of the River Po. On the other hand, on the southern side of the Po Plain, no geomorphological evidence of similar discharge reduction has been found. Here, stratigraphic sections, together with archaeological remains buried under the fluvial deposits, show a reduction in the size of fluvial sediments after the 10th millennium BC. During the Holocene, fluvial sedimentation became finer, and was characterised by minor fluctuations in the rate of deposition, probably related to short and less intense climatic fluctuations. Given the high rate of population growth and the development of human activities since the Neolithic Age, human influence on fluvial dynamics, especially since the Roman Age, prevailed over other factors (i.e., climate, tectonics, vegetation, etc.). During the Holocene, the most important changes in the Po Plain were not modifications in water discharge but in sediment. From the 1st to 3rd Century AD, land grants to war veterans caused almost complete deforestation, generalised soil erosion, and maximum progradation of the River Po delta. At present, land abandonment in the mountainous region has led to reafforestation. Artificial channel control in the

  10. Fingertip replantation using a single volar arteriovenous anastomosis and drainage with a transverse tip incision.

    Science.gov (United States)

    Yabe, T; Muraoka, M; Motomura, H; Ozawa, T

    2001-11-01

    Four cases of fingertip replantation using a single volar arteriovenous anastomosis and drainage with a transverse tip incision are reported. Because of lack of suitable arteries for anastomosis in the amputated finger, in each case a volar radial vein was anastomosed to the proximal digital artery and external drainage was performed through a transverse tip incision. In 3 cases the replanted fingertip survived completely; partial necrosis occurred in 1 case. Because veins are more superficial and larger than arteries, they are more available for anastomosis. The results indicate that this method is a useful alternative in fingertip replantation.

  11. Supercritical strata in Lower Paleozoic fluvial rocks: a super critical link to upper flow regime processes and preservation in nature

    Science.gov (United States)

    Lowe, David; Arnott, Bill

    2015-04-01

    Recent experimental work has much improved our understanding of the lithological attributes of open-channel supercritical flow deposits, namely those formed by antidunes, chutes-and-pools and cyclic steps. However their limited documentation in the ancient sedimentary record brings into question details about their geological preservation. Antidune, chute-and-pool and cyclic step deposits are well developed in sandy ephemeral fluvial deposits of the Upper Cambrian - Lower Ordovician Potsdam Group in the Ottawa Embayment of eastern North America. These high energy fluvial strata form dm- to a few m-thick units intercalated within thick, areally expansive successions of sheet sandstones consisting mostly of wind ripple and adhesion stratification with common deflation lags. Collectively these strata record deposition in a semi-arid environment in which rare, episodic high-energy fluvial events accounted for most of the influx of sediment from upland sources. Following deposition, however, extensive aeolian processes reworked the sediment pile, and hence modified profoundly the preserved stratigraphic record. Antidune deposits occur as 0.2 - 1.6 m thick cosets made up of 2 - 15 cm thick lenticular sets of low angle (≤ 20o) cross-stratified, medium- to coarse-grained sandstone bounded by low-angle (5 - 15o) concave-upward scours and, in many cases, capped by low angle (10 - 15o) convex-upwards symmetrical formsets. Chute-and-pool deposits form single sets, 5 - 55 cm thick and 0.6 - 6 m wide, with scoured bases and low to high angle (5 - 25o) sigmoidal cross-strata consisting of medium- to coarse-grained sandstone. Cyclic step deposits consist of trough cross-stratified sets, 20 cm - 1.6 m thick, 2.5 - 12 m long and 7 - 35 m wide, typically forming trains that laterally are erosively juxtaposed at regularly-spaced intervals. They are composed of medium- to coarse-grained sandstone with concave-up, moderate to high angle (15 - 35o) cross-strata with tangential bases

  12. Implications of the fluvial history of the Wacheqsa River for hydrologic engineering and water use at Chavín de Húntar, Peru

    Science.gov (United States)

    Contreras, Daniel A.; Keefer, David K.

    2009-01-01

    Channeling of water through a variety of architectural features represents a significant engineering investment at the first millennium B.C. ceremonial center of Chavín de Huántar in the Peruvian Central Andes. The site contains extensive evidence of the manipulation of water, apparently for diverse purposes. The present configuration of the two local rivers, however, keeps available water approximately 9m below the highest level of water-bearing infrastructure in the site. Geomorphic and archaeological investigation of the fluvial history of the Wacheqsa River has revealed evidence that the Chavín-era configuration of the Wacheqsa River was different. A substantially higher water level, likely the result of a local impoundment of river water caused by a landslide dam, made the provision of water for the hydrologic system within the site a more readily practical possibility. We review what is known of that system and argue that the fluvial history of the Wacheqsa River is critical to understanding this aspect of hydrologic engineering and ritual practice at Chavín. This study demonstrates the relative rapidity and archaeological relevance of landscape change in a dynamic environment.

  13. Bank-derived material dominates fluvial sediment in a suburban Chesapeake Bay watershed

    Science.gov (United States)

    Cashman, M. J.; Gellis, A.; Gorman-Sanisaca, L.; Noe, G. B.; Cogliandro, V.; Baker, A.

    2017-12-01

    Excess fine sediment is a leading cause of ecological degradation within the Chesapeake Bay watershed. The Piedmont physiographic province, which includes parts of the Washington, D.C. metro area, has the highest sediment yields in the Chesapeake Bay. In order to effectively employ sediment mitigation measures, it is necessary to identify and quantify the contributions of sediments sources within rapidly urbanizing areas in the Piedmont. This sediment fingerprinting study examines the inputs of various sediment sources to Upper Difficult Run (14.2 km2; 22.6% impervious surface), an urbanized watershed in Fairfax County, Virginia. A source sediment library was constructed from collections of stream bank material, forest soils, and road dust from across the watershed. Target fluvial sediments were collected from fine channel margin deposits and from suspended sediment using an autosampler during 16 storm events from 2008 - 2012. Apportionment of the target samples to the source sediments was performed using Sed_SAT, a publically available toolkit for sediment fingerprinting. Bed sediment was found to be dominated by stream bank sources (mean: 96%), with minor contributions from forest (4%) and no detectable contribution from roads (0%). Suspended fine sediments were also found to predominantly originate from stream bank sources (SSC-weighted mean: 91%), with minor contributions from roads (8%), and negligible contributions from forests (1%). Stream bank sources dominated at all discharges, with the greatest contributions from overland sources found only at low discharges. On the rising limb of the hydrograph and at peak flow, sediment concentrations increased due to increasing contributions of bank material rather than surface erosion caused by overland flow. Results demonstrate that stream bank erosion is responsible for the vast majority of fine sediment occurring in this suburban basin of the Chesapeake Bay watershed. This is likely a consequence of storm

  14. Two depositional models for Pliocene coastal plain fluvial systems, Goliad Formation, south Texas Gulf Coastal plain

    International Nuclear Information System (INIS)

    Hoel, H.D.; Galloway, W.E.

    1983-01-01

    The Goliad Formation consists of four depositional systems-the Realitos and Mathis bed-load fluvial systems in the southwest and the Cuero and Eagle Lake mixed-load fluvial systems in the northeast. Five facies are recognized in the Realitos and Mathis bed-load fluvial systems: (1) primary channel-fill facies, (2) chaotic flood channel-fill facies, (3) complex splay facies, (4) flood plain facies, and (5) playa facies. A model for Realitos-Mathis depositional environments shows arid-climate braided stream complexes with extremely coarse sediment load, highly variable discharge, and marked channel instability. Broad, shallow, straight to slightly sinuous primary channels were flanked by wide flood channels. Flood channels passed laterally into broad, low-relief flood plains. Small playas occupied topographic lows near large channel axes. Three facies are recognized in the Cuero and Eagle Lake mixed-load fluvial systems: (1) channel-fill facies, (2) crevasse splay facies, and (3) flood plain facies. A model for Cuero-Eagle Lake depositional environments shows coarse-grained meander belts in a semi-arid climate. Slightly to moderately sinuous meandering streams were flanked by low, poorly developed natural levees. Crevasse splays were common, but tended to be broad and ill-defined. Extensive, low-relief flood plains occupied interaxial areas. The model proposed for the Realitos and Mathis fluvial systems may aid in recognition of analogous ancient depositional systems. In addition, since facies characteristics exercise broad controls on Goliad uranium mineralization, the proposed depositional models aid in defining target zones for Goliad uranium exploration

  15. Comparison of the effects of 23-gauge and 25-gauge microincision vitrectomy blade designs on incision architecture

    Directory of Open Access Journals (Sweden)

    Inoue M

    2014-11-01

    Full Text Available Makoto Inoue,1 Dina Joy K Abulon,2 Akito Hirakata1 1Kyorin Eye Center, School of Medicine, Kyorin University, Tokyo, Japan; 2Alcon Research, Ltd., Irvine, CA, USA Purpose: To compare the effects of different 23- and 25-gauge microincision vitrectomy trocar cannula entry systems on incision architecture.Methods: We tested one ridged microvitreoretinal (MVR, one non-ridged MVR, one pointed beveled, and one round-tipped beveled blade (n=10 per blade design per incision type. Each blade’s straight and oblique incision architecture was assessed in a silicone disc simulating the sclera. Wound leakage under pressure and endoscopic observations were conducted on sclerotomy sites of isolated porcine eyes (n=4 per blade design after simulated vitrectomy.Results: Differences in blade design created distinct incision architecture. Incisions were linear with the ridged MVR blade, flattened “M-shaped” with the non-ridged MVR blade, asymmetrical chevron-shaped with the pointed beveled blade, and curved with the round-tipped beveled blade. With the exception of oblique entry incision thickness, both MVR blade designs created thinner incisions than the beveled blades at entry and exit sites. Only the ridged MVR blade created incisions with no leakage. Vitreous incarceration was observed with all trocar cannula systems.Conclusion: Wound closure in porcine eyes was similar with all blades despite differences in incision architecture. Wound leakage occurred at low to moderate infusion pressures with most blades; no wound leakage was observed with ridged MVR blades. Keywords: entry system, incision closure, leakage, pars plana incision, sclerotomy, trocar blade 

  16. Combined fluvial and pluvial urban flood hazard analysis: method development and application to Can Tho City, Mekong Delta, Vietnam

    Science.gov (United States)

    Apel, H.; Trepat, O. M.; Hung, N. N.; Chinh, D. T.; Merz, B.; Dung, N. V.

    2015-08-01

    Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas, and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either fluvial or pluvial flood hazard, studies of combined fluvial and pluvial flood hazard are hardly available. Thus this study aims at the analysis of fluvial and pluvial flood hazard individually, but also at developing a method for the analysis of combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as example. In this tropical environment the annual monsoon triggered floods of the Mekong River can coincide with heavy local convective precipitation events causing both fluvial and pluvial flooding at the same time. Fluvial flood hazard was estimated with a copula based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. Pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data, and a stochastic rain storm generator. Inundation was simulated by a 2-dimensional hydrodynamic model implemented on a Graphical Processor Unit (GPU) for time-efficient flood propagation modelling. All hazards - fluvial, pluvial and combined - were accompanied by an uncertainty estimation considering the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by

  17. Comparison of incision and drainage against needle aspiration for the treatment of breast abscess.

    Science.gov (United States)

    Naeem, Muhammad; Rahimnajjad, Muhammad Kazim; Rahimnajjad, Nasir Ali; Ahmed, Qazi Jalaluddin; Fazel, Pyar Ali; Owais, Muhammad

    2012-11-01

    We aim to compare the incision and drainage against ultrasound-guided aspiration for the treatment of breast abscesses. Sixty-four patients were randomly allocated to Group A (incision and drainage) and Group B (needle aspiration). Incision and drainage was done under general, whereas aspiration was done under local anesthesia with antibiotic coverage after the pus sample was taken for cultures. Time taken to resolve symptoms including point tenderness, erythema and hyperthermia, recurrence of breast abscess, and healing time was recorded. Patients were followed until 8 weeks. Culture and sensitivity of the pus were done. Data were analyzed in SPSS 16.0. The mean difference of healing time was significant (P = 0.001). A total of 93.3 per cent were healed in Group B and 76.6 per cent in Group A (P = 0.033). Twenty-two samples (34.37%) had no bacterial yield and the remaining 42 samples (65.6%) yielded 11 anaerobic cultures (17.18%) and 31 aerobic cultures (48.4%). Ultrasound-guided aspiration of breast abscesses with the judicious use of antibiotics is a better treatment modality than incision and drainage.

  18. Modelling channel incision and alpine hillslope development using laser altimetry data

    NARCIS (Netherlands)

    Anders, N.S.; Seijmonsbergen, A.C.; Bouten, W.

    2009-01-01

    This paper presents a new approach to simulate drainage basin evolution and demonstrates that high resolution elevation data can be used as useful tool for a dynamic simulation of Alpine landscape development, in which channel incision is incorporated in high spatial detail. A vector channel

  19. The Evolution of the Appendectomy: From Open to Laparoscopic to Single Incision

    Directory of Open Access Journals (Sweden)

    Noah J. Switzer

    2012-01-01

    Full Text Available Beginning with its initial description by Fitz in the 19th century, acute appendicitis has been a significant long-standing medical challenge; today it remains the most common gastrointestinal emergency in adults. Already in 1894, McBurney advocated for the surgical removal of the inflamed appendix and is credited with the initial description of an Open Appendectomy (OA. With the introduction of minimally invasive surgery, this classic approach evolved into a procedure with multiple, smaller incisions; a technique termed Laparoscopic Appendectomy (LA. There is much literature describing the advantages of this newer approach. To name a few, patients have significantly less wound infections, reduced pain, and a reduction in ileus compared with the OA. In the past few years, Single Incision Laparoscopic Appendectomy (SILA has gained popularity as the next major evolutionary advancement in the removal of the appendix. Described as a pioneer in the era of “scarless surgery,” it involves only one transumbilical incision. Patients are postulated to have reduced post-operative complications such as infection, hernias, and hematomas, as well as a quicker recovery time and less post-operative pain scores, in comparison to its predecessors. In this review, we explore the advancement of the appendectomy from open to laparoscopic to single incision.

  20. Effects of Bank Vegetation and Incision on Erosion Rates in an Urban Stream

    Directory of Open Access Journals (Sweden)

    Emily Arnold

    2018-04-01

    Full Text Available Changing land-use associated with urbanization has resulted in shifts in riparian assemblages, stream hydraulics, and sediment dynamics leading to the degradation of waterways. To combat degradation, restoration and management of riparian zones is becoming increasingly common. However, the relationship between flora, especially the influence of invasive species, on sediment dynamics is poorly understood. Bank erosion and turbidity were monitored in the Tookany Creek and its tributary Mill Run in the greater Philadelphia, PA region. To evaluate the influence of the invasive species Reynoutria japonica (Japanese knotweed on erosion, reaches were chosen based on their riparian vegetation and degree of incision. Bank pins and turbidity loggers were used to estimate sediment erosion. Erosion calculations based on bank pins suggest greater erosion in reaches dominated by knotweed than those dominated by trees. For a 9.5-month monitoring period, there was 29 cm more erosion on banks that were also incised, and 9 cm more erosion in banks with little incision. Turbidity responses to storm events were also higher (77 vs. 54 NTU (nephelometric turbidity unit in reaches with knotweed, although this increase was found when the reach dominated by knotweed was also incised. Thus, this study linked knotweed to increased erosion using multiple methods.

  1. Computed tomography contrast media extravasation: treatment algorithm and immediate treatment by squeezing with multiple slit incisions.

    Science.gov (United States)

    Kim, Sue Min; Cook, Kyung Hoon; Lee, Il Jae; Park, Dong Ha; Park, Myong Chul

    2017-04-01

    In our hospital, an adverse event reporting system was initiated that alerts the plastic surgery department immediately after suspecting contrast media extravasation injury. This system is particularly important for a large volume of extravasation during power injector use. Between March 2011 and May 2015, a retrospective chart review was performed on all patients experiencing contrast media extravasation while being treated at our hospital. Immediate treatment by squeezing with multiple slit incisions was conducted for a portion of these patients. Eighty cases of extravasation were reported from approximately 218 000 computed tomography scans. The expected extravasation volume was larger than 50 ml, or severe pressure was felt on the affected limb in 23 patients. They were treated with multiple slit incisions followed by squeezing. Oedema of the affected limb disappeared after 1-2 hours after treatment, and the skin incisions healed within a week. We propose a set of guidelines for the initial management of contrast media extravasation injuries for a timely intervention. For large-volume extravasation cases, immediate management with multiple slit incisions is safe and effective in reducing the swelling quickly, preventing patient discomfort and decreasing skin and soft tissue problems. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  2. Normalized Urinary Flow at Puberty after Tubularized Incised Plate Urethroplasty for Hypospadias in Childhood.

    Science.gov (United States)

    Andersson, Marie; Doroszkiewicz, Monika; Arfwidsson, Charlotte; Abrahamsson, Kate; Sillén, Ulla; Holmdahl, Gundela

    2015-11-01

    An obstructive urinary flow pattern is frequently seen after tubularized incised plate urethroplasty for hypospadias. However, the significance of this finding has not been determined and long-term results are few. We describe postoperative long-term uroflowmetry results after puberty in males who underwent tubularized incised plate urethroplasty in childhood. A total of 126 boys underwent tubularized incised plate urethroplasty for distal penile to mid shaft hypospadias at Queen Silvia Children's Hospital in Gothenburg between 1999 and 2003. Of the patients 48 were toilet trained at surgery. We report on 40 patients who had data available at 2 and 12 months postoperatively, 7 years postoperatively and at puberty (median age 15.0 years, range 13.7 to 17.1). Of the patients 31 had distal and 9 had mid penile hypospadias. Clinical examination, urinary medical history, uroflowmetry and ultrasound measuring residual urine were performed. Maximum urinary flow was correlated to age and voided volume, using Miskolc nomograms for comparison of percentiles. At 1 year postoperatively 15 boys (37.5%) had normal urinary flow (above 25th percentile), compared to 16 (40%) at 7 years and 38 (95%) at puberty (p puberty for boys with hypospadias treated with tubularized incised plate urethroplasty. Unless symptoms occur, a conservative approach seems preferable. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  3. Full-Thickness Retinochoroidal Incision in the Management of Central Retinal Vein Occlusion

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    San-Ni Chen

    2015-01-01

    Full Text Available Purpose. To evaluate the clinical outcomes in patients with central retinal vein occlusion (CRVO treated with full-thickness retinochoroidal incisions and to compare whether there is difference in treatment response in ischemic and nonischemic CRVO. Methods. Retrospective study of patients of CRVO receiving full-thickness retinochoroidal incisions in Changhua Christian Hospital. Fluorescein angiography (FA, slit-lamp biomicroscopy, indirect funduscopy, best corrected visual acuity, and central macular thickness (CMT measured by optical coherence tomography were performed pre- and postoperatively. Patients were divided into an ischemic and nonischemic group according to the findings of FA. Patients were followed up for at least 1 year. Results. Twenty-eight eyes (14 ischemic and 14 nonischemic CRVO were included. Functional retinochoroidal venous anastomosis (RCVA was achieved in 48 of the 65 retinochoroidal incisions (73.8%. Central macular thickness (CMT and retinal hemorrhage decreased significantly after the surgery. Significant visual gain was observed postoperatively in the nonischemic group, but not in the ischemic group. Postoperative complications included vitreous hemorrhage (17.8%, neovascular glaucoma (7.1%, and preretinal fibrovasular membrane (10.7%, all of which were in the ischemic group. Conclusions. RCVA formation induced by retinochoroidal incisions could improve venous flow, and decrease CMT and retinal hemorrhage. However, only eyes with nonischemic CRVO showed visual improvement.

  4. Addition of rectus sheath relaxation incisions to emergency midline laparotomy for peritonitis to prevent fascial dehiscence.

    Science.gov (United States)

    Marwah, Sanjay; Marwah, Nisha; Singh, Mandeep; Kapoor, Ajay; Karwasra, Rajender Kumar

    2005-02-01

    The incidence of fascial dehiscence and incisional hernia after two methods for abdominal wound closure (rectus sheath relaxation incisions and conventional mass closure) was studied in a randomized prospective clinical trial in a consecutive series of 100 patients undergoing midline laparotomy for peritonitis. The two groups were well matched for etiologies of peritonitis, the surgical procedures performed, and the presence of known risk factors for fascial dehiscence. Fifty patients each were randomized either to the conventional continuous mass closure procedure or the rectus sheath relaxation incision technique (designed to increase wound elasticity and decrease tension in the suture line) using identical polypropylene sutures. The incidence of postoperative complications such as duration of ileus, chest infection, and wound infection were not statistically different between the two groups. The intensity of postoperative pain in the rectus sheath relaxation incision group was significantly less. The incidence of wound hematoma was significantly increased in the rectus sheath relaxation incision group. The incidences of fascial dehiscence (16% vs,28%; p cases of peritonitis using the rectus sheath relaxation technique is safe and less painful, provides increased wound elasticity and decreased tension on the suture line, and significantly decreases the incidence of wound dehiscence.

  5. Outcomes of single-stage total arch replacement via clamshell incision

    Directory of Open Access Journals (Sweden)

    Ishizaka Toru

    2011-09-01

    Full Text Available Abstract Background Treatment of complex aortic pathologies involving the transverse arch with extensive involvement of the descending aorta remains a surgical challenge. Since clamshell incision provides superior exposure of the entire thoracic aorta, we evaluated the use of this technique for single-stage total arch replacement by arch vessel reconstruction. Methods The arch-first technique combined with clamshell incision was used in 38 cases of aneurysm and aortic disease in 2008 and 2009. Extensive total arch replacement was used with clamshell incision for reconstruction of arch vessels under deep hypothermic circulatory arrest. Results Overall 30-day mortality was 13%. The mean operating time was approximately 8 hours. Deep hypothermia resulted in mean CPB time exceeding 4.5 hours and mean duration of circulatory arrest was 25 minutes. The overall postoperative temporary and permanent neurologic dysfunction rates were 3% and 3% for elective and 3% and 0% for emergency surgery, respectively. All patients except the five who died in hospital were discharged without nursing care after an average post-operative hospital stay of 35 days. Conclusions The arch-first technique, combined with clamshell incision, provides expeditious replacement of the thoracic aorta with an acceptable duration of hypothermic circulatory arrest and minimizes the risk of retrograde atheroembolism by using antegrade perfusion.

  6. Influence of different phacoemulsification incision on postoperative corneal astigmatism for cataract patients

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    Zhao-Rong Zeng

    2014-05-01

    Full Text Available AIM: To compare the effect of different phacoemulsification incision on postoperative corneal astigmatism for cataract patients. METHODS: The cataract patients were selected in our hospital. The patients were divided into control group(corneal limbus opposite curved scleral tunnel incision groupand observation group(above the top of cornea or temporal transparent corneal incision grouprandomly. At 1wk; 1 and 3mo after surgery, the change of corneal astigmatism and vision of the patients in two groups were compared and analyzed. RESULTS:Compared with control group, 1wk; 1 and 3mo after surgery, the average corneal astigmatism and surgically induced corneal astigmatism of the patients in observation group were decreased significantly. The visual acuity and corrected visual acuity were increased significantly. There was statistically significant(PPCONCLUSION: Center distance and small incision corneal phacoemulsification can reduce postoperative astigmatism and improve postoperative visual acuity for cataract patients. It provides guarantee for further strengthen the clinical treated effect for cataract patients.

  7. Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam

    Science.gov (United States)

    Apel, Heiko; Martínez Trepat, Oriol; Nghia Hung, Nguyen; Thi Chinh, Do; Merz, Bruno; Viet Dung, Nguyen

    2016-04-01

    Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either a fluvial or pluvial flood hazard, studies of a combined fluvial and pluvial flood hazard are hardly available. Thus this study aims to analyse a fluvial and a pluvial flood hazard individually, but also to develop a method for the analysis of a combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as an example. In this tropical environment the annual monsoon triggered floods of the Mekong River, which can coincide with heavy local convective precipitation events, causing both fluvial and pluvial flooding at the same time. The fluvial flood hazard was estimated with a copula-based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. The pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data and a stochastic rainstorm generator. Inundation for all flood scenarios was simulated by a 2-dimensional hydrodynamic model implemented on a Graphics Processing Unit (GPU) for time-efficient flood propagation modelling. The combined fluvial-pluvial flood scenarios were derived by adding rainstorms to the fluvial flood events during the highest fluvial water levels. The probabilities of occurrence of the combined events were determined assuming independence of the two flood types and taking the seasonality and probability of

  8. Laparoscopic surgery for esophageal achalasia: Multiport vs single-incision approach.

    Science.gov (United States)

    Fukuda, Shuichi; Nakajima, Kiyokazu; Miyazaki, Yasuhiro; Takahashi, Tsuyoshi; Makino, Tomoki; Kurokawa, Yukinori; Yamasaki, Makoto; Miyata, Hiroshi; Takiguchi, Shuji; Mori, Masaki; Doki, Yuichiro

    2016-02-01

    SILS can potentially improve aesthetic outcomes without adversely affecting treatment outcomes, but these outcomes are uncertain in laparoscopic Heller-Dor surgery. We determined if the degree of patient satisfaction with aesthetic outcomes progressed with the equivalent treatment outcomes after the introduction of a single-incision approach to laparoscopic Heller-Dor surgery. We retrospectively reviewed 20 consecutive esophageal achalasia patients (multiport approach, n = 10; single-incision approach, n = 10) and assessed the treatment outcomes and patient satisfaction with the aesthetic outcomes. In the single-incision approach, thin supportive devices were routinely used to gain exposure to the esophageal hiatus. No statistically significant differences in the operating time (210.2 ± 28.8 vs 223.5 ± 46.3 min; P = 0.4503) or blood loss (14.0 ± 31.7 vs 16.0 ± 17.8 mL; P = 0.8637) were detected between the multiport and single-incision approaches. We experienced no intraoperative complications. Mild dysphagia, which resolved spontaneously, was noted postoperatively in one patient treated with the multiport approach. The reduction rate of the maximum lower esophageal sphincter pressure was 25.1 ± 34.4% for the multiport approach and 21.8 ± 19.2% for the single-incision approach (P = 0.8266). Patient satisfaction with aesthetic outcomes was greater for the single-incision approach than for the multiport approach. When single-incision laparoscopic Heller-Dor surgery was performed adequately and combined with the use of thin supportive devices, patient satisfaction with the aesthetic outcomes was higher and treatment outcomes were equivalent to those of the multiport approach. © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

  9. River longitudinal profiles and bedrock incision models: Stream power and the influence of sediment supply

    Science.gov (United States)

    Sklar, Leonard; Dietrich, William E.

    The simplicity and apparent mechanistic basis of the stream power river incision law have led to its wide use in empirical and theoretical studies. Here we identify constraints on its calibration and application, and present a mechanistic theory for the effects of sediment supply on incision rates which spotlights additional limitations on the applicability of the stream power law. On channels steeper than about 20%, incision is probably dominated by episodic debris flows, and on sufficiently gentle slopes, sediment may bury the bedrock and prevent erosion. These two limits bound the application of the stream power law and strongly constrain the possible combination of parameters in the law. In order to avoid infinite slopes at the drainage divide in numerical models of river profiles using the stream power law it is commonly assumed that the first grid cell is unchanneled. We show, however, that the size of the grid may strongly influence the calculated equilibrium relief. Analysis of slope-drainage area relationships for a river network in a Northern California watershed using digital elevation data and review of data previously reported by Hack reveal that non-equilibrium profiles may produce well defined slope-area relationships (as expected in equilibrium channels), but large differences between tributaries may point to disequilibrium conditions. To explore the role of variations in sediment supply and transport capacity in bedrock incision we introduce a mechanistic model for abrasion of bedrock by saltating bedload. The model predicts that incision rates reach a maximum at intermediate levels of sediment supply and transport capacity. Incision rates decline away from the maximum with either decreasing supply (due to a shortage of tools) or increasing supply (due to gradual bed alluviation), and with either decreasing transport capacity (due to less energetic particle movement) or increasing transport capacity (due less frequent particle impacts per unit bed

  10. Effects of ZnO nanoparticles and Zn{sup 2+} on fluvial biofilms and the related toxicity mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yi; Wang, Chao [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Hou, Jun, E-mail: hhuhjyhj@126.com [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Dai, Shanshan [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Wang, Peifang, E-mail: pfwang2005@hhu.edu.cn [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Miao, Lingzhan; Lv, Bowen; Yang, Yangyang; You, Guoxiang [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China)

    2016-02-15

    Zinc oxide nanoparticles (ZnO NPs) used in consumer products are largely released into the environment through the wastewater stream. The health hazard of ZnO NPs and the contribution of dissolved Zn{sup 2+} in toxicity of ZnO NPs has attracted extensive worldwide attention. In this study, the toxic effects of ZnO nanoparticles (ZnO NPs) and the effects of dissolved Zn{sup 2+} on fluvial biofilms were investigated. At the end of the exposure time (21 days), scanning electron microscopy (SEM) images and bioaccumulation experiments revealed that large quantities of ZnO NPs were adsorbed on the biofilm. The algal biomasses were significantly decreased by six- and eleven-fold compared with the control (1.43 μg/L) by exposure to concentrations of 100 mg/L ZnO NPs and 7.85 mg/L Zn{sup 2+}, respectively. Moreover, under the same exposure conditions, the quantum yields presented contents of 53.33 and 33.33% relative to the control, and a shift in the community composition that manifested as a strong reduction in diatoms was observed from 7 days and reached 15.63 and 6.25% of the control after 21 days of exposure, respectively. The reductions in bacteria viability and reactive oxygen species (ROS) production were noticeably enhanced following exposure to 100 mg/L ZnO NPs and 7.85 mg/L Zn{sup 2+}, respectively. Additionally, the acute and rapid toxicity of Zn{sup 2+} and the increasing toxicity of the ZnO NPs with increased bioaccumulation were noted in the exposure experiment. - Highlights: • Fluvial biofilm was exposed to ZnO NPs and the dissolved Zn{sup 2+}. • Chl-a and Φ{sub M} decreased at high doses (100 and 7.85 mg/L of ZnO NPs and Zn{sup 2+}). • A shift in the algae community composition was observed at high dosage levels. • The enhanced production of ROS declined the bacteria viability. • Zn{sup 2+} was more toxic than that of the ZnO-NPs.

  11. Effects of ZnO nanoparticles and Zn"2"+ on fluvial biofilms and the related toxicity mechanisms

    International Nuclear Information System (INIS)

    Xu, Yi; Wang, Chao; Hou, Jun; Dai, Shanshan; Wang, Peifang; Miao, Lingzhan; Lv, Bowen; Yang, Yangyang; You, Guoxiang

    2016-01-01

    Zinc oxide nanoparticles (ZnO NPs) used in consumer products are largely released into the environment through the wastewater stream. The health hazard of ZnO NPs and the contribution of dissolved Zn"2"+ in toxicity of ZnO NPs has attracted extensive worldwide attention. In this study, the toxic effects of ZnO nanoparticles (ZnO NPs) and the effects of dissolved Zn"2"+ on fluvial biofilms were investigated. At the end of the exposure time (21 days), scanning electron microscopy (SEM) images and bioaccumulation experiments revealed that large quantities of ZnO NPs were adsorbed on the biofilm. The algal biomasses were significantly decreased by six- and eleven-fold compared with the control (1.43 μg/L) by exposure to concentrations of 100 mg/L ZnO NPs and 7.85 mg/L Zn"2"+, respectively. Moreover, under the same exposure conditions, the quantum yields presented contents of 53.33 and 33.33% relative to the control, and a shift in the community composition that manifested as a strong reduction in diatoms was observed from 7 days and reached 15.63 and 6.25% of the control after 21 days of exposure, respectively. The reductions in bacteria viability and reactive oxygen species (ROS) production were noticeably enhanced following exposure to 100 mg/L ZnO NPs and 7.85 mg/L Zn"2"+, respectively. Additionally, the acute and rapid toxicity of Zn"2"+ and the increasing toxicity of the ZnO NPs with increased bioaccumulation were noted in the exposure experiment. - Highlights: • Fluvial biofilm was exposed to ZnO NPs and the dissolved Zn"2"+. • Chl-a and Φ_M decreased at high doses (100 and 7.85 mg/L of ZnO NPs and Zn"2"+). • A shift in the algae community composition was observed at high dosage levels. • The enhanced production of ROS declined the bacteria viability. • Zn"2"+ was more toxic than that of the ZnO-NPs.

  12. Reaction and relaxation in a coarse-grained fluvial system following catchment-wide disturbance

    Science.gov (United States)

    Tunnicliffe, Jon; Brierley, Gary; Fuller, Ian C.; Leenman, Anya; Marden, Mike; Peacock, Dave

    2018-04-01

    The Waiapu River catchment (drainage area of 1734-km2) is one of the most prolific conveyors of sediment in the world, annually delivering roughly 35 Mt of fine material to the ocean from eroding gullies, hillslopes, and reworked sediment on valley floors. Tectonic and geologic influences, in combination with a dynamic climate influenced by tropical cyclones and clearance of vegetation from steep hillslopes, predisposes this region to high rates of erosion. The bedload sediment regime of the river is strongly influenced by several exceptionally large gullies and gully complexes that produce a coarse-grained, poorly sorted sediment mixture. Rapid abrasion and breakdown leads to high rates of suspended sediment yield. A wave of bedload material, manifesting as elevated bed levels and significant widening of active alluvial fills, has been triggered by large inputs of hillslope material from a few key tributary catchments following Cyclone Bola in 1988. We review the evidence for the relaxation process of the sedimentary system in the subsequent 29 years, appraising some of the legacy effects that may endure, as associated with reworking of the considerable alluvial stores within the Waiapu system. We use Structure-from-Motion (SfM) techniques and archival aerial photos to quantify changes in sediment storage at the base of two major gully systems in recent decades. A record of over 850 cross section surveys at 62 sites on 10 rivers throughout the catchment (1958-2017) indicates recent transition from a trend of continuous accumulation to downcutting and remobilisation of valley-bottom deposits. The channel cross sections provide a minimum estimate of sediment flux from source areas to the lower reaches of the river, giving a rudimentary but spatially extensive picture of the wave of material cascading through the drainage network. The largest impacts occur in the upper steepland rivers, closest to the landslide-derived sediment supply. Transport rates here, as

  13. A new technique, combined plication-incision (CPI, for correction of penile curvature

    Directory of Open Access Journals (Sweden)

    Hamed Abdalla Hamed

    Full Text Available ABSTRACT Introduction Penile curvature (PC can be surgically corrected by either corporoplasty or plication techniques. These techniques can be complicated by post-operative: penile shortening, recurrent PC, painful/palpable suture knots and erectile dysfunction. Objective To avoid the complications of corporoplasty and plication techniques using a new technique: combined plication-incision (CPI. Materials and Methods Two groups (1&2 were operated upon: group 1 using CPI and group 2 using the 16-dot technique. In CPI, dots were first marked as in 16 dot technique. In each group of 4 dots the superficial layer of tunica albuginea was transversely incised (3-6mm at the first and last dots. Ethibond 2/0, passed through the interior edge of the first incision plicating the intermediate 2 dots and passed out of the interior edge of the last incision, was tightened and ligated. Vicryle 4/0, passed through the exterior edges of the incisions, was tightened and ligated to cover the ethibond knot. Results Twelve (57.1 % participants in group 2 complained of a bothering palpable knot compared to none in group 1 with statistically significant difference (P=0.005. Postoperative shortening (5mm of erect penis, encountered in 9 participants, was doubled in group 2 but with insignificant difference (P>0.05. Post-operative recurrence of PC, was encountered in only 1 (4.8% participant in group 2, compared to none in group 1, with insignificant difference (P>0.05. Post-operative erectile rigidity was normally maintained in all participants. Conclusion The new technique was superior to the 16-dot technique for correction of PC.

  14. [Is there a relation between mammaplasties incisions and the final shape of the breast?].

    Science.gov (United States)

    Moufarrège, R; Dionyssopoulos, A; Aymeric, A; Sauvageau, J

    2010-04-01

    The results of reduction mammoplasty and mastopexy demonstrate a great variety of shapes derived from the particularities inherent to each technique. More precisely, it has become apparent to us that the usage of an abnormally long vertical scar leads to a suboptimal final shape of the breast due to the excessive projection compared to its height. Although our clientele continually asks to minimize scars, we have noticed a resurgence in the literature of vertical incision mammoplasty techniques albeit with a scar of an excessive length. The multitude of publications leads to an evident and consistent conclusion: breasts reconstructed with an overly long vertical incision all suffer the same deformity characterized by a banana or squash-shaped breast. We studied the totality of publications on vertical incision technique mammoplasty from the last 15 years and realised they all presented the same problem: an abnormally low height/projection ratio. These numbers have been confronted by the golden ratio established by the first author (2005) [1]. The breast's golden ratio developed by Moufarrège is optimal at a number close to, or superior to 2. Results between 2 and 1.5 are acceptable. All height/projection ratios inferior to 1.5 correspond to suboptimal breast shapes. Furthermore, the totality of results in the vertical scar mammoplasty technique which displayed unsatisfying results had a height/projection ratio inferior to 1.5. Those who promote the vertical incision have the greatest drive to encourage other plastic surgeons to abandon the traditional mutilating boat anchor scar. Nevertheless, they should always remember the deforming effect caused by exaggerated vertical incisions which may be avoided by transforming it into an inverted T with short horizontal branches, a small price to pay to obtain a superior aesthetic result. Copyright 2009 Elsevier Masson SAS. All rights reserved.

  15. Physical Drivers Vs. Effects of the Wolf-Elk Trophic Cascade on Fluvial Channel Planform, Olympic National Park, Washington

    Science.gov (United States)

    East, A. E.; Jenkins, K. J.; Happe, P. J.; Bountry, J.; Beechie, T. J.; Mastin, M. C.; Sankey, J. B.; Randle, T. J.

    2016-12-01

    Identifying the relative contributions of physical and ecological processes to channel evolution remains a substantial challenge in fluvial geomorphology. We use a 74-year aerial photographic record of the Hoh, Queets, Quinault, and Elwha Rivers, Olympic National Park, Washington, U.S.A., to investigate whether physical or trophic-cascade-driven ecological factors—excessive elk impacts after wolves were extirpated a century ago—are the dominant controls on channel planform of these gravel-bed rivers. We find that channel width and braiding show strong relationships with recent flood history; all four rivers have widened significantly in recent decades, consistent with increased flood activity since the 1970s. Channel planform also reflects sediment-supply changes, shown, for example, by the response of the Elwha River to a landslide. We surmise that the Hoh River, which shows a multi-decadal trend toward greater braiding, is adjusting to increased sediment supply associated with rapid glacial retreat. These rivers demonstrate rapid transmission of climatic signals through relatively short sediment-routing systems that lack substantial buffering by sediment storage. We infer no correspondence between channel evolution and elk abundance, suggesting that in this system effects of the wolf-driven trophic cascade are subsidiary to physical controls on channel morphology. Our examinations of stage-discharge history, historical maps, photographs, and descriptions, and empirical geomorphic thresholds do not support a previous conceptual model that these rivers underwent a fundamental geomorphic transition (widening, and a shift from single-thread to braided) resulting from large elk populations in the early 20th century. These findings differ from previous interpretations of Olympic National Park river dynamics, and also contrast with previous findings in Yellowstone National Park, where legacy effects of abundant elk nearly a century ago apparently still affect

  16. Pre- and post-remediation characterization of acid-generating fluvial tailings material

    Science.gov (United States)

    Smith, Kathleen S.; Walton-Day, Katherine; Hoal, Karin O.; Driscoll, Rhonda L.; Pietersen, K.

    2012-01-01

    The upper Arkansas River south of Leadville, Colorado, USA, contains deposits of fluvial tailings from historical mining operations in the Leadville area. These deposits are potential non-point sources of acid and metal contamination to surface- and groundwater systems. We are investigating a site that recently underwent in situ remediation treatment with lime, fertilizer, and compost. Pre- and post-remediation fluvial tailings material was collected from a variety of depths to examine changes in mineralogy, acid generation, and extractable nutrients. Results indicate sufficient nutrient availability in the post-remediation near-surface material, but pyrite and acid generation persist below the depth of lime and fertilizer addition. Mineralogical characterization performed using semi-quantitative X-ray diffraction and quantitative SEM-based micro-mineralogy (Mineral Liberation Analysis, MLA) reveal formation of gypsum, jarosite, and complex coatings surrounding mineral grains in post-remediation samples.

  17. Dose response of artificial irradiation of fluvial sediment sample for ESR dating

    International Nuclear Information System (INIS)

    Liu Chunru; Yin Gongming; Gao Lu; Li Jianping; Han Fei; Lin Min

    2011-01-01

    ESR dating samples need be irradiated to obtain dose response curve and the equivalent dose. The artificial dose rate is about 1 x 10 -1 -1 x 10 2 Gy/min, whereas the natural dose rate is about 3 Gy/ka. Therefore, one must be sure whether the much higher artificial dose rate is suitable for the ESR dating study. In this paper, we use different artificial dose rate to irradiate the same fluvial sample and measure the quartz Al centre ESR signal under the same conditions. The dose response curves are compared, in an attempt to gain a preliminary knowledge on that problem and build a good foundation for our ESR dating studies on fluvial samples. (authors)

  18. Estuary-wide genetic stock distribution and salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  19. Volcanic or Fluvial Channels on Ascraeus Mons: Focus on the Source Area of Sinuous Channels on the Southeast Rift Apron

    Science.gov (United States)

    Signorella, J. D.; de Wet, A. P.; Bleacher, J. E.; Collins, A.; Schierl, Z. P.; Schwans, B.

    2012-03-01

    This study focuses on the source area of sinuous channels on the southeast rift apron on Ascraeus Mons, Mars and attempts to understand whether the channels were formed through volcanic or fluvial processes.

  20. Minimal Nasolabial Incision Technique for Nasolabial Fold Modification in Patients With Facial Paralysis.

    Science.gov (United States)

    Faris, Callum; Heiser, Alyssa; Jowett, Nate; Hadlock, Tessa

    2018-03-01

    Creation of symmetrical nasolabial folds (NLFs) is important in the management of the paralyzed face. Established techniques use a linear incision in the NLF, and technical refinements now allow the linear incision to be omitted. This retrospective case series was conducted in a tertiary care setting from February 2, 2017, to June 7, 2017. Participants were all patients (N = 21) with peripheral facial paralysis who underwent NLF modification that used the minimal nasolabial incision technique at the Massachusetts Eye and Ear Infirmary Facial Nerve Center from February 1, 2015, through August 31, 2016. Patient-reported outcome measures using the validated, quality-of-life Facial Clinimetric Evaluation (FaCE) Scale; clinician-reported facial function outcomes using a validated electronic clinician-graded facial paralysis assessment (eFACE); layperson assessment of the overall aesthetic outcome of the NLF; and expert-clinician scar assessment of the NLF. Of the 21 patients who underwent NLF modification that used the minimal nasolabial incision technique, 9 patients (43%) were female and 12 (57%) were male. The mean age was 41 (range, 9-90) years; 17 patients (81%) were adults (≥18 years) and 4 (19%) were children (<18 years). Overall, significant improvements were observed after NLF modification in all outcome measures as graded by both clinicians and patients. The mean (SD) scores for total eFACE were 60.7 (14.9) before the operation and 77.2 (8.9) after the operation (mean difference, 16.5 [95% CI, 8.5-24.2]; P < .001). The mean (SD) static eFACE scores were 61.4 (20.6) before the operation and 82.7 (12.4) after the operation (mean difference, 21.3 [95% CI, 10.7-31.9]; P < .001). The mean (SD) FaCE quality-of-life scores were 51.3 (20.1) before the operation and 70.3 (12.6) after the operation (mean difference, 19.0 [95% CI, 6.5-31.6]; P  =  .001). The layperson self-assessment of the overall aesthetic outcome of the NLF modification was

  1. A Hot Knife Through Ice-Cream: Earthflow Response to Channel Incision (Or Channel Response to Earthflows?), Eel River Canyon, California

    Science.gov (United States)

    Mackey, B. H.; Roering, J. J.; McKean, J. A.

    2007-12-01

    Abundant glacier-like earthflow features are recognized as a primary erosional process in the highly erodable Franciscan Melange of the Eel River Basin, CA. Despite their prominence in this "melting ice-cream" topography, many questions regarding their effects on the long term sediment flux from this rapidly eroding basin remain unresolved. For example, does an earthflow's basal shear zone propagate vertically downwards with vertical river incision? What controls the upslope and lateral extent of individual earthflows? How does the erosive power of a river influence the rate of earthflow movement, or conversely do earthflow toe deposits regulate the rate of river incision? Here we present preliminary findings derived from study of 200km2 of lidar data (1m resolution) covering hillslopes adjacent to 30km of the Eel River. Lidar allows detailed analysis of the interaction between earthflows and the drainage network, and we document how inferred changes in local base level are propagated throughout adjacent hillslopes via earthflow movement. The most active earthflows (determined by field surveying and analysis of aerial photos rectified using lidar- generated digital topography) coincide with locally steep sections of channel, while downstream of the most active flows we frequently observe less-active or dormant earthflows. This observation supports the idea that the locations of the most active earthflows coincide with headward propagating knickpoints in the channel. The rate of earthflow movement appears to slow when an earthflow exhausts the upslope area of easily mobilized sediment. Earthflow toes can protrude directly into the channel, causing the channel to narrow and steepen, and even undercut the opposite bank. Large resistant boulders (>2m diameter) transported by the earthflow accumulate in the streambed and appear to both act as a check on further channel incision and earthflow movement. In contrast, areas adjacent to active earthflows exhibit smooth

  2. The Role of Hand-Assisted Laparoscopic Technique in the Age of Single-Incision Laparoscopy: An Effective Alternative to Avoid Open Conversion in Colorectal Surgery.

    Science.gov (United States)

    Jung, Kyung Uk; Yun, Seong Hyeon; Cho, Yong Beom; Kim, Hee Cheol; Lee, Woo Yong; Chun, Ho-Kyung

    2018-04-01

    Continuous efforts to reduce the numbers and size of incisions led to the emergence of a new technique, single-incision laparoscopic surgery (SILS). It has been rapidly accepted as the preferred surgical approach in the colorectal area. In the age of SILS, what is the role of hand-assisted laparoscopic surgery (HALS)? We introduce the way to take advantage of it, as an effective alternative to avoid open conversion. This is a retrospective review of prospectively collected data of SILS colectomies performed by a single surgeon in Samsung Medical Center between August 2009 and December 2012. Out of 631 cases of SILS colectomy, 47 cases needed some changes from the initial approach. Among these, five cases were converted to HALS. Four of them were completed successfully without the need for open conversion. One patient with rectosigmoid colon cancer invading bladder was finally opened to avoid vesical trigone injury. The mean operation time of the 4 patients was 265.0 minutes. The mean estimated blood loss was 587.5 mL. The postoperative complication rate associated with the operation was 25%. Conversion from SILS to HALS in colorectal surgery was feasible and effective. It seemed to add minimal morbidity while preserving advantages of minimally invasive surgery. It could be considered an alternative to open conversion in cases of SILS, especially when the conversion to conventional laparoscopy does not seem to be helpful.

  3. Experimental insights into organic carbon oxidation potential during fluvial transport without floodplain storage

    Science.gov (United States)

    Scheingross, J. S.; Hovius, N.; Sachse, D.; Vieth-Hillebrand, A.; Turowski, J. M.; Hilton, R. G.

    2016-12-01

    Over geologic timescales, the exchange of organic carbon (OC) between the atmosphere, rock, and biosphere is thought to be a major control on global climate. CO2 flux estimates from oxidation of rock-derived OC and sequestration of biospheric OC during fluvial transit from source to sink are approximately the same order of magnitude or larger than those from silicate weathering. Despite field data showing loss of OC moving downstream in lowland rivers, it is unclear if losses occur primarily during active fluvial transport within the river, where OC is in continual motion within an aerated environment, or during longer periods when OC is temporarily stored in river floodplains which may be anoxic. This represents a major knowledge gap, as the unknown location of OC oxidation (i.e., river vs. floodplain) limits our ability to develop process-based models that can be employed to predict OC losses, constrain carbon budgets, and unravel links between climate, tectonics, and erosion. To fill this gap, we investigated the potential for OC oxidation in laboratory experiments simulating fluvial transport without floodplain storage. Mixtures of OC-rich and siliciclastic sediment were transported for distances of 2000 km in annular flumes while making time-series measurements of sediment TOC and water DOC concentrations. Initial results for transport of OC-rich soil show increasing DOC with transport distance to levels that represent a transfer of 2% of the total OC from the solid to the dissolved phase; however, we observed no detectable change in the solid-phase TOC. Similar results were obtained in a control experiment with identical sediment in still water. These preliminary results suggest minimal OC oxidation within our experiment, and, to the extent that such experiments represent natural transport through river systems, are consistent with the hypothesis that OC losses may occur primarily during floodplain storage rather than fluvial transport.

  4. Insights into organic carbon oxidation potential during fluvial transport from laboratory and field experiments

    Science.gov (United States)

    Scheingross, J. S.; Dellinger, M.; Eglinton, T. I.; Fuchs, M. C.; Golombek, N.; Hilton, R. G.; Hovius, N.; Lupker, M.; Repasch, M. N.; Sachse, D.; Turowski, J. M.; Vieth-Hillebrand, A.; Wittmann, H.

    2017-12-01

    Over geologic timescales, the exchange of organic carbon (OC) between the atmosphere, hydropshere, biosphere and geosphere can be a major control on atmospheric carbon dioxide concentrations. The carbon fluxes from the oxidation of rock-derived OC (a CO2 source) and erosion, transport, and burial of biospheric OC (a potential CO2 sink) during fluvial transit are approximately the same order of magnitude or larger than those from silicate weathering. Despite field data showing increasing oxidation of OC moving downstream in lowland rivers, it is unclear if losses occur primarily during active fluvial transport, where OC is in continual motion within an aerated river, or during periods of temporary storage in river floodplains which may be anoxic. The unknown location of OC oxidation (i.e., river vs. floodplain) limits our ability to mechanistically link geochemical and geomorphic processes which are required to develop models capable of predicting OC losses, constrain carbon budgets, and unravel links between climate, tectonics, and erosion. To fill this knowledge gap, we investigated OC oxidation in controlled laboratory experiments and a simplified field setting. We performed experiments in annular flumes that simulate fluvial transport without floodplain storage, allowing mixtures of OC-rich and siliciclastic sediment to be transported for distances of 1000 km. Preliminary experiments exploring both rock-derived and biospheric OC sources show minimal OC oxidation during active river transport, consistent with the idea that the majority of OC loss occurs during transient floodplain storage. These results are also consistent with new field data collected in the Rio Bermejo, Argentina, a lowland river traversing 800 km with no tributary inputs, where aged floodplain deposits have 3 to 10 times lower OC concentrations compared to modern river sediments. Together our field data and experiments support the hypothesis that oxidation of OC occurs primarily during

  5. Reconstructing paleo-discharge from geometries of fluvial sinuous ridges on Earth and Mars

    Science.gov (United States)

    Hayden, A.; Lamb, M. P.; Mohrig, D. C.; Williams, R. M. E.; Myrow, P.; Ewing, R. C.; Cardenas, B. T.; Findlay, C. P., III

    2017-12-01

    Sinuous, branching networks of topographic ridges resembling river networks are common across Mars, and show promise for quantifying ancient martian surface hydrology. There are two leading formation mechanisms for ridges with a fluvial origin. Inverted channels are ridges that represent casts (e.g., due to lava fill) of relict river channel topography, whereas exhumed channel deposits are eroded remnants of a more extensive fluvial deposit, such as a channel belt. The inverted channel model is often assumed on Mars; however, we currently lack the ability to distinguish these ridge formation mechanisms, motivating the need for Earth-analog study. To address this issue, we studied the extensive networks of sinuous ridges in the Ebro basin of northeast Spain. The Ebro ridges stand 3-15 meters above the surrounding plains and are capped by a cliff-forming sandstone unit 3-10 meters thick and 20-50 meters in breadth. The caprock sandstone bodies contain bar-scale cross stratification, point-bar deposits, levee deposits, and lenses of mudstone, indicating that these are channel-belt deposits, rather than casts of channels formed from lateral channel migration, avulsion and reoccupation. In plan view, ridges form segments branching outward to the north resembling a distributary network; however, crosscutting relationships indicate that ridges cross at different stratigraphic levels. Thus, the apparent network in planview reflects non-uniform exhumation of channel-belt deposits from multiple stratigraphic positions, rather than an inverted coeval river network. As compared to the inverted channel model, exhumed fluvial deposits indicate persistent fluvial activity over geologic timescales, indicating the potential for long-lived surface water on ancient Mars.

  6. Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir, Class I

    Energy Technology Data Exchange (ETDEWEB)

    Bou-Mikael, Sami

    2002-02-05

    This report demonstrates the effectiveness of the CO2 miscible process in Fluvial Dominated Deltaic reservoirs. It also evaluated the use of horizontal CO2 injection wells to improve the overall sweep efficiency. A database of FDD reservoirs for the gulf coast region was developed by LSU, using a screening model developed by Texaco Research Center in Houston. The results of the information gained in this project is disseminated throughout the oil industry via a series of SPE papers and industry open forums.

  7. Contribution of radioactive tracers to sediment transport study in fluvial flows

    International Nuclear Information System (INIS)

    Wilson Junior, G.

    1995-01-01

    The uses of radioactive tracers in sediment transport studies are presented in this report to evidence the importance of: Open channel researches, to describe field applications in waterways; Simultaneous utilization of classical methods and radiotracer techniques, in fluvial and estuarine environments; Development of radiotracers techniques applied in dynamic sedimentology. The report illustrated with some experiments carried out in Brazil and France, in open channel and natural flows. (author). 5 refs, 4 figs

  8. A multi-scale approach of fluvial biogeomorphic dynamics using photogrammetry.

    Science.gov (United States)

    Hortobágyi, Borbála; Corenblit, Dov; Vautier, Franck; Steiger, Johannes; Roussel, Erwan; Burkart, Andreas; Peiry, Jean-Luc

    2017-11-01

    Over the last twenty years, significant technical advances turned photogrammetry into a relevant tool for the integrated analysis of biogeomorphic cross-scale interactions within vegetated fluvial corridors, which will largely contribute to the development and improvement of self-sustainable river restoration efforts. Here, we propose a cost-effective, easily reproducible approach based on stereophotogrammetry and Structure from Motion (SfM) technique to study feedbacks between fluvial geomorphology and riparian vegetation at different nested spatiotemporal scales. We combined different photogrammetric methods and thus were able to investigate biogeomorphic feedbacks at all three spatial scales (i.e., corridor, alluvial bar and micro-site) and at three different temporal scales, i.e., present, recent past and long term evolution on a diversified riparian landscape mosaic. We evaluate the performance and the limits of photogrammetric methods by targeting a set of fundamental parameters necessary to study biogeomorphic feedbacks at each of the three nested spatial scales and, when possible, propose appropriate solutions. The RMSE varies between 0.01 and 2 m depending on spatial scale and photogrammetric methods. Despite some remaining difficulties to properly apply them with current technologies under all circumstances in fluvial biogeomorphic studies, e.g. the detection of vegetation density or landform topography under a dense vegetation canopy, we suggest that photogrammetry is a promising instrument for the quantification of biogeomorphic feedbacks at nested spatial scales within river systems and for developing appropriate river management tools and strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Applying fluvial geomorphology to river channel management: Background for progress towards a palaeohydrology protocol

    Science.gov (United States)

    Gregory, K. J.; Benito, G.; Downs, P. W.

    2008-06-01

    Significant developments have been achieved in applicable and applied fluvial geomorphology as shown in publications of the last three decades, analyzed as the basis for using results of studies of environmental change as a basis for management. The range of types of publications and of activities are more pertinent to river channel management as a result of concern with sustainability, global climate change, environmental ethics, ecosystem health concepts and public participation. Possible applications, with particular reference to river channel changes, include those concerned with form and process, assessment of channel change, urbanization, channelization, extractive industries, impact of engineering works, historical changes in land use, and restoration with specific examples illustrated in Table 1. In order to achieve general significance for fluvial geomorphology, more theory and extension by modelling methods is needed, and examples related to morphology and process characteristics, integrated approaches, and changes of the fluvial system are collected in Table 2. The ways in which potential applications are communicated to decision-makers range from applicable outputs including publications ranging from review papers, book chapters, and books, to applied outputs which include interdisciplinary problem solving, educational outreach, and direct involvement, with examples summarized in Table 3. On the basis of results gained from investigations covering periods longer than continuous records, a protocol embracing palaeohydrological inputs for application to river channel management is illustrated and developed as a synopsis version (Table 4), demonstrating how conclusions from geomorphological research can be expressed in a format which can be considered by managers.

  10. Tratamiento de los espacios fluviales urbanos andaluces en la planificación territorial y sectorial

    Directory of Open Access Journals (Sweden)

    David González Rojas

    2017-01-01

    Full Text Available La recuperación y conservación de los espacios fluviales urbanos debe insertarse dentro de los procesos de planificación territorial y sectorial. El presente trabajo analiza la evolución y las transformaciones de los espacios fluviales urbanos en Andalucía durante las últimas décadas, a través del análisis de los distintos planes. Para el estudio de las relaciones entre el planeamiento territorial y sectorial y los espacios fluviales urbanos se ha realizado una recopilación de los documentos actualmente aprobados o en tramitación. En el artículo se destacan los avances durante el periodo estudiado, pero también las inercias, resistencias y nuevos problemas asociados. El esfuerzo realizado para la ordenación de los ríos a su paso por las ciudades no ha tenido su reflejo en los resultados obtenidos, siendo las interrelaciones entre la gestión del agua y del territorio (regional, subregional y municipal una cuestión no resuelta.

  11. Pemaknaan Filsafati Kearifan Lokal untuk Adaptasi Masyarakat terhadap Ancaman Bencana Marin dan Fluvial di Lingkungan Kepesisiran

    Directory of Open Access Journals (Sweden)

    S Sunarto

    2011-07-01

    Full Text Available The purpose of this research was to study the philosophical meaning of local wisdom that developed in the communities in the coastal environment, particularly in the eastern coast of Central Java. The method used for this philosophical meaning using the approach of geomorphological hermeneutics and disaster semiotics. The results of this research indicate that identified local wisdom in the form of cultural semiotics and faunal semiotics to anticipate the hazards of climate change as marine hazard and fluvial hazard. Cultural semiotics found in the form of advice that still need to be interpreted with a geomorphological hermeneutics approach order to use it to adapt to the coastal environment against marine hazard. The cultural semiotics has a geomorphological philosophical meaning as natural cycle that leads to dynamic equilibrium, not the philosophical meaning that leads to the view of anthropocentrism. In addition, also found cultural semiotics of “Dina Rèntèng” based on the philosophical views of ecocentrism. The cultural semiotics is used in society to adapt to the fluvial hazard. Faunal semiotics found in the form of anomalous crab behavior as a form of adaptation due to its response to environmental condition. The faunal semiotics has been used as a guide for the community to adapt to the fluvial hazard. Because of the local wisdom is loaded with philosophical meaning, it can be metatourism assets, so it can convert harm into benefit.

  12. High temporal resolution in situ measurement of the effective particle size characteristics of fluvial suspended sediment.

    Science.gov (United States)

    Williams, N D; Walling, D E; Leeks, G J L

    2007-03-01

    This paper reports the use of a LISST-100 device to monitor the effective particle size characteristics of suspended sediment in situ, and at a quasi-continuous temporal resolution. The study site was located on the River Exe at Thorverton, Devon, UK. This device has not previously been utilized in studies of fluvial suspended sediment at the storm event scale, and existing studies of suspended sediment dynamics have not involved such a high temporal resolution for extended periods. An evaluation of the field performance of the instrument is presented, with respect to innovative data collection and analysis techniques. It was found that trends in the effective particle size distribution (EPSD) and degree of flocculation of suspended sediment at the study site were highly complex, and showed significant short-term variability that has not previously been documented in the fluvial environment. The collection of detailed records of EPSD facilitated interpretation of the dynamic evolution of the size characteristics of suspended sediment, in relation to its likely source and delivery and flocculation mechanisms. The influence of measurement frequency is considered in terms of its implications for future studies of the particle size of fluvial suspended sediment employing in situ data acquisition.

  13. Optimizing sampling strategy for radiocarbon dating of Holocene fluvial systems in a vertically aggrading setting

    International Nuclear Information System (INIS)

    Toernqvist, T.E.; Dijk, G.J. Van

    1993-01-01

    The authors address the question of how to determine the period of activity (sedimentation) of fossil (Holocene) fluvial systems in vertically aggrading environments. The available data base consists of almost 100 14 C ages from the Rhine-Meuse delta. Radiocarbon samples from the tops of lithostratigraphically correlative organic beds underneath overbank deposits (sample type 1) yield consistent ages, indicating a synchronous onset of overbank deposition over distances of at least up to 20 km along channel belts. Similarly, 14 C ages from the base of organic residual channel fills (sample type 3) generally indicate a clear termination of within-channel sedimentation. In contrast, 14 C ages from the base of organic beds overlying overbank deposits (sample type 2), commonly assumed to represent the end of fluvial sedimentation, show a large scatter reaching up to 1000 14 C years. It is concluded that a combination of sample types 1 and 3 generally yields a satisfactory delimitation of the period of activity of a fossil fluvial system. 30 refs., 11 figs., 4 tabs

  14. Transport and deposition of plutonium-contaminated sediments by fluvial processes, Los Alamos Canyon, New Mexico

    International Nuclear Information System (INIS)

    Graf, W.L.

    1996-01-01

    Between 1945 and 1952 the development of nuclear weapons at Los Alamos National Laboratory, New Mexico, resulted in the disposal of plutonium into the alluvium of nearby Acid and (to a lesser degree) DP Canyons. The purpose of this paper is to explore the connection between the disposal sites and the main river, a 20 km link formed by the fluvial system of Acid, Pueblo, DP, and Los Alamos Canyons. Empirical data from 15 yr of annual sediment sampling throughout the canyon system has produced 458 observations of plutonium concentration in fluvial sediments. These data show that, overall, mean plutonium concentrations in fluvial sediment decline from 10,000 fCi/g near the disposal area to 100 fCi/g at the confluence of the canyon system and the Rio Grande. Simulations using a computer model for water, sediment, and plutonium routing in the canyon system show that discharges as large as the 25 yr event would fail to develop enough transport capacity to completely remove the contaminated sediments from Pueblo Canyon. Lesser flows would move some materials to the Rio Grande by remobilization of stored sediments. The simulations also show that the deposits and their contaminants have a predictable geography because they occur where stream power is low, hydraulic resistance is high, and the geologic and/or geomorphic conditions provide enough space for storage. 38 refs., 13 figs., 1 tab

  15. Cannabidiol Is a Potential Therapeutic for the Affective-Motivational Dimension of Incision Pain in Rats

    Directory of Open Access Journals (Sweden)

    Karina Genaro

    2017-06-01

    Full Text Available Background: Pain involves different brain regions and is critically determined by emotional processing. Among other areas, the rostral anterior cingulate cortex (rACC is implicated in the processing of affective pain. Drugs that interfere with the endocannabinoid system are alternatives for the management of clinical pain. Cannabidiol (CBD, a phytocannabinoid found in Cannabis sativa, has been utilized in preclinical and clinical studies for the treatment of pain. Herein, we evaluate the effects of CBD, injected either systemically or locally into the rACC, on mechanical allodynia in a postoperative pain model and on the negative reinforcement produced by relief of spontaneous incision pain. Additionally, we explored whether CBD underlies the reward of pain relief after systemic or rACC injection.Methods and Results: Male Wistar rats were submitted to a model of incision pain. All rats had mechanical allodynia, which was less intense after intraperitoneal CBD (3 and 10 mg/kg. Conditioned place preference (CPP paradigm was used to assess negative reinforcement. Intraperitoneal CBD (1 and 3 mg/kg inverted the CPP produced by peripheral nerve block even at doses that do not change mechanical allodynia. CBD (10 to 40 nmol/0.25 μL injected into the rACC reduced mechanical allodynia in a dose-dependent manner. CBD (5 nmol/0.25 μL did not change mechanical allodynia, but reduced peripheral nerve block-induced CPP, and the higher doses inverted the CPP. Additionally, CBD injected systemically or into the rACC at doses that did not change the incision pain evoked by mechanical stimulation significantly produced CPP by itself. Therefore, a non-rewarding dose of CBD in sham-incised rats becomes rewarding in incised rats, presumably because of pain relief or reduction of pain aversiveness.Conclusion: The study provides evidence that CBD influences different dimensions of the response of rats to a surgical incision, and the results establish the rACC as a

  16. Heterogeneity in a Suburban River Network: Understanding the Impact of Fluvial Wetlands on Dissolved Oxygen and Metabolism in Headwater Streams

    Science.gov (United States)

    Cain, J. S.; Wollheim, W. M.; Sheehan, K.; Lightbody, A.

    2014-12-01

    Low dissolved oxygen content in rivers threatens fish populations, aquatic organisms, and the health of entire ecosystems. River systems with high fluvial wetland abundance and organic matter, may result in high metabolism that in conjunction with low re-aeration rates, lead to low oxygen conditions. Increasing abundance of beaver ponds in many areas may exacerbate this phenomenon. This research aims to understand the impact of fluvial wetlands, including beaver ponds, on dissolved oxygen (D.O.) and metabolism throughout the headwaters of the Ipswich R. watershed, MA, USA. In several fluvial wetland dominated systems, we measured diel D.O. and metabolism in the upstream inflow, the surface water transient storage zones of fluvial wetland sidepools, and at the outflow to understand how the wetlands modify dissolved oxygen. D.O. was also measured longitudinally along entire surface water flow paths (x-y km long) to determine how low levels of D.O. propagate downstream. Nutrient samples were also collected to understand how their behavior was related to D.O. behavior. Results show that D.O. in fluvial wetlands has large swings with periods of very low D.O. at night. D.O. swings were also seen in downstream outflow, though lagged and somewhat attenuated. Flow conditions affect the level of inundation and the subsequent effects of fluvial wetlands on main channel D.O.. Understanding the D.O. behavior throughout river systems has important implications for the ability of river systems to remove anthropogenic nitrogen.

  17. The "Propeller" incision for transpalatal advancement pharyngoplasty: a new approach to reduce post-operative oronasal fistulae.

    Science.gov (United States)

    Shine, Neville Patrick; Lewis, Richard Hamilton

    2008-09-01

    To present a new soft tissue approach for transpalatal advancement pharyngoplasty (TPA), the propeller incision, and to compare the rates of post-operative oronasal fistula in those undergoing TPA with the traditional "Gothic Arch" incision described by Woodson and those with the propeller incision. A prospectively maintained adult sleep apnoea surgery database was used to identify those patients undergoing TPA, either alone or in combination with other procedures, for obstructive sleep apnoea syndrome (OSAS) between February 2001 and September 2006 in a tertiary referral centre by a single surgeon (RHL). In addition to the incision used during TPA, patient demographic data, previous surgery of the upper airways, smoking history, pre-operative body mass index, respiratory disturbance index, oxygen saturation index and the occurrence of oronasal fistula post-operatively, were recorded. The propeller incision technique is described. A total of 89 patients who underwent TPA were identified. A total of 49 patients had a "Gothic Arch" incision and 40 had a "Propeller" incision. The two groups of patients were comparable in age, sex, previous tonsillar and uvulopalatopharyngoplasty surgery, smoking histories and pre-operative disease severity. In the "Gothic Arch" group, eight patients (16%) developed oronasal fistulae in the post-operative period versus only one patient (2.5%) in the "Propeller" group. The difference between the two groups was statistically significant (P=0.038, Fisher's exact test). Of the total cases with post-operative oronasal fistula (n=9), only one patient (from the Gothic Arch incision group) required operative closure which was performed under local anesthesia and healed without complication. The propeller incision provides an anatomically sensible axial-based flap that provides adequate access to perform TPA. It is associated with a lower incidence of oronasal fistula and is recommended by the authors.

  18. The Brahmaputra River: a stratigraphic analysis of Holocene avulsion and fluvial valley reoccupation history

    Science.gov (United States)

    Hartzog, T. R.; Goodbred, S. L.

    2011-12-01

    The Brahmaputra River, one of the world's largest braided streams, is a major component of commerce, agriculture, and transportation in India and Bangladesh. Hence any significant change in course, morphology, or behavior would be likely to influence the regional culture and economy that relies on this major river system. The history of such changes is recorded in the stratigraphy deposited by the Brahmaputra River during the Holocene. Here we present stratigraphic analysis of sediment samples from the boring of 41 tube wells over a 120 km transect in the upper Bengal Basin of northern Bangladesh. The transect crosses both the modern fluvial valley and an abandoned fluvial valley about 60 km downstream of a major avulsion node. Although the modern Brahmaputra does not transport gravel, gravel strata are common below 20 m with fluvial sand deposits dominating most of the stratigraphy. Furthermore, the stratigraphy preserves very few floodplain mud strata below the modern floodplain mud cap. These preliminary findings will be assessed to determine their importance in defining past channel migration, avulsion frequency, and the reoccupation of abandoned fluvial valleys. Understanding the avulsion and valley reoccupation history of the Brahmaputra River is important to assess the risk involved with developing agriculture, business, and infrastructure on the banks of modern and abandoned channels. Based on the correlation of stratigraphy and digital surface elevation data, we hypothesize that the towns of Jamalpur and Sherpur in northern Bangladesh were once major ports on the Brahmaputra River even though they now lie on the banks of small underfit stream channels. If Jamalpur and Sherpur represent the outer extent of the Brahmaputra River braid-belt before the last major avulsion, these cities and any communities developed in the abandoned braid-belt assume a high risk of devastation if the next major avulsion reoccupies this fluvial valley. It is important to

  19. Fluvial organic carbon losses from oil palm plantations on tropical peat, Sarawak, Southeast Asia

    Science.gov (United States)

    Cook, Sarah; Page, Susan; Evans, Chris; Whelan, Mick; Gauci, Vincent; Lip Khoon, Kho

    2017-04-01

    Tropical peatlands are valuable stores of carbon. However, tropical peat swamp forests (TPSFs) in Southeast Asia have increasingly been converted to other land-uses. For example, more than 25% of TPSFs are now under oil palm plantations. This conversion - requiring felling and burning of trees and drainage of the peat - can enhance carbon mineralization, dissolved organic carbon (DOC) losses and can contribute significantly to global anthropogenic greenhouse gas emissions, changing these natural carbon sinks into carbon sources. At present, relatively few scientifically sound studies provide dependable estimates of gaseous and fluvial carbon losses from oil palm plantations or from drained tropical peat in general. Here we present an annual (54 week) estimate of the export of dissolved and particulate organic carbon in water draining two oil palm estates and nearby stands of TPSF in Sarawak, Malaysia, subjected to varying degrees of past anthropogenic disturbance. Spectrophotometric techniques including SUVA254 (Specific Ultra-Violet Absorption) were used to gain insight into the aromaticity and subsequent bioavailability of the exported DOC. Water draining plantation and deforested land had a higher proportion of labile carbon compared to water draining forested areas. Preliminary data suggest a total fluvial DOC flux from plantations of ca. 190 g C m-2 year-1; nearly three times estimates from intact TPSFs (63 g C m-2 year-1). DOC accounted for between 86 % - 94 % of the total organic carbon lost (most of which was bioavailable). Wit et al. (2015) estimates that an average of 53 % of peat-derived DOC is decomposed and emitted as CO2, on a monthly basis. Based on these estimates our data suggests an additional 101 g CO2 m-2 may be emitted indirectly from fluvial organic carbon in degraded TPSFs per year. Overall, these findings emphasize the importance of including fluvial organic carbon fluxes when quantifying the impact of anthropogenic disturbance on the

  20. Suspended sediment transport trough a large fluvial-tidal channel network

    Science.gov (United States)

    Wright, Scott A.; Morgan-King, Tara L.

    2015-01-01

    The confluence of the Sacramento and San Joaquin Rivers, CA, forms a large network of interconnected channels, referred to as the Sacramento-San Joaquin Delta (the Delta). The Delta comprises the transition zone from the fluvial influences of the upstream rivers and tidal influences of San Francisco Bay downstream. Formerly an extensive tidal marsh, the hydrodynamics and geomorphology of Delta have been substantially modified by humans to support agriculture, navigation, and water supply. These modifications, including construction of new channels, diking and draining of tidal wetlands, dredging of navigation channels, and the operation of large pumping facilities for distribution of freshwater from the Delta to other parts of the state, have had a dramatic impact on the physical and ecological processes within the Delta. To better understand the current physical processes, and their linkages to ecological processes, the USGS maintains an extensive network of flow, sediment, and water quality gages in the Delta. Flow gaging is accomplished through use of the index-velocity method, and sediment monitoring uses turbidity as a surrogate for suspended-sediment concentration. Herein, we present analyses of the transport and dispersal of suspended sediment through the complex network of channels in the Delta. The primary source of sediment to the Delta is the Sacramento River, which delivers pulses of sediment primarily during winter and spring runoff events. Upon reaching the Delta, the sediment pulses move through the fluvial-tidal transition while also encountering numerous channel junctions as the Sacramento River branches into several distributary channels. The monitoring network allows us to track these pulses through the network and document the dominant transport pathways for suspended sediment. Further, the flow gaging allows for an assessment of the relative effects of advection (the fluvial signal) and dispersion (from the tides) on the sediment pulses as they

  1. Late Noachian Icy Highlands climate model: Exploring the possibility of transient melting and fluvial/lacustrine activity through peak annual and seasonal temperatures

    Science.gov (United States)

    Palumbo, Ashley M.; Head, James W.; Wordsworth, Robin D.

    2018-01-01

    greenhouse warming, the process would be required to continue for ∼(21-550) × 103 years. Therefore, peak seasonal melting of snow and ice could induce the generation of meltwater and fluvial and lacustrine activity in a ;cold and icy; Late Noachian climate in a manner similar to that observed in the MDV. A potential shortcoming of this mechanism is that independent estimates of the required runoff rates for valley network formation are much higher than those predicted by this mechanism when considering a circular orbit, even when accounting for additional atmospheric warming. However, we consider that a relatively higher eccentricity condition (0.17) may produce the necessary runoff rates: for the perihelion scenario in which perihelion occurs during southern hemispheric summer, intense melting will occur in the near-equatorial regions and in the southern hemisphere, producing runoff rates comparable to those required for valley network formation (∼mm/day). In the opposite perihelion scenario, the southern hemisphere will experience very little summertime melting. Thus, this seasonal melting mechanism is a strong candidate for formation of the valley networks when considering a relatively high eccentricity (0.17) because this mechanism is capable of (1) producing meltwater in the equatorial region where valley networks are abundant, (2) continuously producing seasonal meltwater for the estimated time duration of valley network formation, (3) yielding the amount of meltwater necessary to incise the valley networks within this time period, and (4) by considering a perihelion scenario in which half of the duration of valley network formation is spent with peak summertime conditions during perihelion in each hemisphere, higher runoff rates are produced than in a circular orbit and the rates may be comparable to those required for valley network formation.

  2. Single-incision video-assisted anatomical segmentectomy with handsewn bronchial closure for endobronchial lipoma.

    Science.gov (United States)

    Galvez, Carlos; Sesma, Julio; Bolufer, Sergio; Lirio, Francisco; Navarro-Martinez, Jose; Galiana, Maria; Baschwitz, Benno; Rivera, Maria Jesus

    2016-08-01

    Endobronchial lipomas are rare benign tumors whose symptoms are usually confused with recurrent infections or even asthma diagnosis, and mostly caused by endobronquial obstructive component which also conditions severity. We report a case of a 60-year-old man with a right-lower lobe upper-segment endobronchial myxoid tumor with uncertain diagnosis. We performed a single incision video-assisted anatomical segmentectomy and wedge bronchoplasty with handsewn closure to achieve complete resection and definitive diagnosis. During the postoperative air leak was not observed and there was no complication, with low pain scores and complete recovery. Final pathological exam showed endobronchial lipoma. Single-incision (SI) anatomical segmentectomies are lung-sparing resections for benign or low-grade malignancies with diagnostic and therapeutic value, and the need for a wedge bronchoplasty is not a necessary indication for conversion to multiport or open thoracotomy.

  3. Can post-sternotomy mediastinitis be prevented by a closed incision management system?

    Directory of Open Access Journals (Sweden)

    Dohmen, Pascal M.

    2014-09-01

    Full Text Available [english] Post-sternotomy mediastinitis is a serious complication after cardiothoracic surgery and contribute significantly to post-operative morbidity, mortality, and healthcare costs. Negative pressure wound therapy is today’s golden standard for post-sternotomy mediastinitis treatment. A systematic literature search was conducted at PubMed until October 2012 to analyse whether vacuum-assisted closure technique prevents mediastinitis after clean surgical incisions closure. Today’s studies showed reduction of post-sternotomy mediastinitis including a beneficial socio-economic impact. Current studies, however included only high-risk patients, hence furthermore, larger randomised controlled trials are warranted to clarify the benefit for using surgical incision vacuum management systems in the general patient population undergoing sternotomy and clarify risk factor interaction.

  4. Radiological assessment of 50 cases of incisive or maxillary neoplasia in the dog

    International Nuclear Information System (INIS)

    Frew, D.G.; Dobson, J.M.

    1992-01-01

    This paper reviews the radiological features of 50 canine incisive or maxillary tumours and discusses the value of radiological assessment in the diagnosis and staging of these tumours. The 50 tumours examined included 21 sarcomas, 15 carcinomas, three melanomas and an assortment of benign tumours of the oral cavity. There was not any site specificity for the different histological tumour types within the upper dental arcade, although fibrosarcomas had a tendency to be maxillary whereas the squamous cell carcinomas were equally distributed between the incisive and maxillary regions. Seventy-eight per cent of fibrosarcomas, 82 per cent of squamous cell carcinoma and all three melanomas examined showed radiological evidence of bone involvement. Radiographic changes were also seen in the benign tumours. The pattern of growth of tumours correlated with the radiological changes observed. Malignant tumours showed a tendency to irregular or aggressive bone loss whereas bone production predominated in the benign tumours

  5. Diagnosis and management of maxillary incisors affected by incisal wear: an interdisciplinary case report.

    Science.gov (United States)

    Bernardo, Jussara Karina; Maia, Elaine A Vilela; Cardoso, Antônio Carlos; de Araújo Júnior, Edson Medeiros; Monteiro Júnior, Sylvio

    2002-01-01

    In the attempt to restore anterior teeth affected by erosion and bruxism, many clinicians have been frustrated with the constant restorative failures. Frequently, these failures are attributed to the restorative materials employed, especially in cases in which composite resins are used. However, some flaws of the restorations are related to the oversight of occlusal principles. The purpose of this article is to discuss the etiology, signs, and symptoms of incisal wear, with special attention to that caused by bruxism and chemical erosion. Relatively simple management techniques (e.g., occlusal adjustment, adhesive restorations) are proposed, and the diagnosis and management of a representative clinical case is presented. In some cases of bruxism and/or dental erosion, it is possible to acquire space to recuperate the esthetics and function of maxillary incisors affected by incisal wear through a conservative treatment associated with the control of the etiologic factors.

  6. A STUDY ON EFFICACY OF MANUAL SMALL INCISION CATARACT SURGERY BY TEMPORAL APPROACH

    Directory of Open Access Journals (Sweden)

    Vinodhini Kannan

    2018-01-01

    Full Text Available BACKGROUND Manual Small Incision Cataract Surgery (MSICS is a well-known technique of cataract surgery owing to its advantage of a selfsealing suture less incision with least surgically induced astigmatism at a low cost. It is a safe, simple, consistent, stable and cost-effective technique with various modifications that involve site, size, type of incision and method of nucleus delivery. One such modification is Temporal Incision MSICS, where the cataract surgery is done by a temporal approach, which is equally good compared to the superior incision. This study was done retrospectively to analyse the visual outcome of patients operated by Manual SICS - Temporal Approach, using the WHO criteria and to establish its efficacy as a good surgical technique. MATERIALS AND METHODS Records of patients operated for senile cataract by a single surgeon by Temporal MSICS using a temporal sclerocorneal incision of 6-6.5 mm, during a 1-year period, were analysed retrospectively. Post-operative followup records of POD-1 and subsequent follow-ups at 1 st week and 6 th week were recorded for visual outcome. RESULTS Out of the 83 cases analysed retrospectively, majority of them were found to be between 61-70 years with a female Preponderance. Most of the cases were found to have senile immature cataract (55 patients, with Grade III nuclear sclerosis (52 cases. The pre-operative visual acuity was poor <6/60 in 72 cases (86.7% and borderline in 11 cases (14.5%. 55 cases (66.3% had a 6.5 mm scleral incision and the remaining 28 cases (33.7% had a 6 mm incision. Average duration of surgery noted was 8.35 minutes. Striate Keratopathy was the most common 1 st POD complication followed by corneal oedema. Striate keratopathy was the most common complication at the 1 st week followup followed by pigment dispersion. Majority of cases (76 cases were found to have been complication free at the end of 6 weeks. At the end of 6 weeks post-operatively as per records, 80 cases

  7. Single-incision, laparoscopic-assisted jejunal resection and anastomosis following a gunshot wound.

    Science.gov (United States)

    Rubin, Jacob A; Shigemoto, Reynsen; Reese, David J; Case, J Brad

    2015-01-01

    A 2 yr old castrated male Pomeranian was evaluated for a 6 wk history of chronic vomiting, intermittent anorexia, and lethargy. Physical examination revealed a palpable, nonpainful, soft-tissue mass in the midabdominal area. Abdominal radiographs and ultrasound revealed a focal, eccentric thickening of the jejunal wall with associated jejunal mural foreign body and partial mechanical obstruction. Following diagnosis of a partial intestinal obstruction as the cause of chronic vomiting, the patient underwent general anesthesia for a laparoscopic-assisted, midjejunal resection and anastomosis using a single-incision laparoscopic surgery port. The patient was discharged the day after surgery, and clinical signs abated according to information obtained during a telephone interview conducted 2 and 8 wk postoperatively. The dog described in this report is a unique case of partial intestinal obstruction treated by laparoscopic-assisted resection and anastomosis using a single-incision laparoscopic surgery port.

  8. Early response of local steroid injection versus mini incision technique in treatment of carpal tunnel syndrome

    International Nuclear Information System (INIS)

    Awan, A.S.; Khan, A.; Afridi, S.A.; Khan, R.S.

    2015-01-01

    Carpal tunnel syndrome Carpal tunnel syndrome (CTS) is one of the commonest peripheral neuropathies which effects mainly middle aged women. Different techniques are being tried to decrease the post-operative pain in patients operated for CTS. The objective of this study was to compare effectiveness of local injection of steroid and mini incision technique in the treatment of carpal tunnel syndrome. Methods: This randomized control trial was conducted at department of Orthopedics and department of Neurosurgery, Ayub Teaching Hospital, Abbottabad from Aug 2011 to Feb 2013. A total of 116 patients of CTS were randomly allocated to either of the two groups. Fifty-eight Patient in Group A were subjected to local steroid injection and the same number of patient in Group B underwent mini incision technique. All patients of were advised to report to the OPD after one month to determine intervention effectiveness in terms of improvement in at least one grade of pain. Results: In this study mean age of the patients was 32.8 ± 5.1 years. Female gender was in dominance with 99 (86.3%) cases. In this study we compared the effectiveness of local steroid injection and mini incision technique in the treatment of carpel tunnel syndrome. We found out that the steroid injection was effective in 69.0% cases while mini incision technique was effective in 56.9% cases. The difference being statistically insignificant with a p-value of 0.17. Conclusion: The difference in pain after 1 month of the intervention was not statistically significant. (author)

  9. Preputial reconstruction and tubularized incised plate urethroplasty in proximal hypospadias with ventral penile curvature

    OpenAIRE

    Bhat, Amilal; Gandhi, Ajay; Saxena, Gajendra; Choudhary, Gautam Ram

    2010-01-01

    Aims : Objective of this study was to assess the feasibility and results of preputial reconstruction and tubularized incised plate urethroplasty (TIP) in patients of proximal hypospadias with ventral penile curvature. Materials and Methods : Twenty-seven patients of proximal hypospadias who underwent preputioplasty with TIP were evaluated retrospectively. Ventral curvature was corrected by mobilization of the urethral plate with the corpus spongiosum and the proximal urethra; dorsal plica...

  10. Femtosecond laser based small incision lenticule extraction for moderate and high myopia

    DEFF Research Database (Denmark)

    Hjortdal, Jesper Østergaard; Asp, Sven; Ivarsen, Anders

    Femtosecond laser based small incision lenticule extraction for moderate and high myopia. Jesper Hjortdal, Sven Asp, Anders Ivarsen, Anders Vestergaard Department of Ophthalmology, Aarhus University Hospital, Denmark Purpose: ReLEx® smile is a new keratorefractive procedure whereby a stromal lent....... Refractive predictability, safety and patient satisfaction at 3 months seems equal to ReLEx flex and FS-LASIK. Optimizing laser energy settings and surgeon experience is important to minimize initial inferior results....

  11. Modified Lengthening Temporalis Myoplasty Involving an Extended Lazy-S Incision to Avoid Facial Scar Formation.

    Science.gov (United States)

    Oji, Tomito; Hayashi, Akiteru; Ogino, Akihiro; Onishi, Kiyoshi

    2018-05-01

    Lengthening temporalis myoplasty is a faster and less invasive alternative to free muscle transfer for smile reconstruction. However, it requires a nasolabial fold incision, which leaves a midfacial scar. Based on esthetic considerations, a modified approach, involving an extended lazy-S (parotidectomy) incision instead of a nasolabial fold incision, was developed. A cadaveric study involving 10 hemifaces was conducted. From February 2013 to March 2016, the modified lengthening temporalis myoplasty procedure was employed in 10 patients. The results were graded from 1 (poor) to 5 (excellent) according to the Terzis grading system. The excursion of the oral commissure was also measured. The extended lazy-S incision provides easy and safe access to the coronoid process and good visibility. The patients' mean age was 56.5 years, and the mean duration of the postoperative follow-up period was 22.2 months. The patients' underlying conditions included acoustic neuroma (n = 2), Bell palsy (n = 3), congenital conditions (n = 2), brain infarction (n = 1), Ramsay Hunt syndrome (n = 1), and malignant parotid lymphoma (n = 1). One patient suffered a surgical site infection, which was successfully treated with irrigation. All the patients achieved improvements in smile symmetry: 2, 5, and 3 patients obtained excellent, good, and moderate results, respectively. The excursion of the oral commissure ranged from 5 to 10 mm. The modified lengthening temporalis myoplasty procedure provides satisfactory functional outcomes without causing significant complications. It does not leave a facial scar and is a preferable option, especially for young and female patients, and patients who have undergone ablative surgery involving the parotid region.

  12. Lateral Nail Fold Incision Technique for Venous Anastomosis in Fingertip Replantation.

    Science.gov (United States)

    Jeon, Byung-Joon; Yang, Jae-Won; Roh, Si Young; Ki, Sae Hwi; Lee, Dong Chul; Kim, Jin Soo

    2016-01-01

    Successful venous anastomosis is one of the most important factors in fingertip replantation. Volar veins in the fingertip course proximally in a random pattern, which makes it difficult to find out the exact locations. Although dorsal veins in the lateral nail fold have constant location and adequate diameter for anastomosis, they have been known as hard to dissect from the immobile subcutaneous tissue. The authors present a new lateral nail fold incision technique for venous anastomosis in the fingertip amputations. From February 2010 to October 2010, 9 replantations using the new incision and venous anastomosis technique were performed in 9 patients. The levels of amputations were from the nail base to half of the nail bed. After repairing the proper digital arteries, a skin incision was made along the junction between the lateral nail fold and nail bed. Careful dissection was performed to isolate the veins in the lateral nail fold. After evaluation of the suitability of the vessel, venous anastomosis was performed. Seven male and 2 female patients were enrolled in this study. Appropriate dorsal veins for anastomosis could be found in 8 of 9 patients. All the replanted stumps survived without venous congestion and following additional procedures. A sizable volar or dorsal vein could not be found in 1 patient. The salvage technique was required in this patient. Dorsal veins in the lateral nail fold can be found easily because of the constant anatomical location. The new incision on the lateral nail fold provides not only sufficient operative field for anastomosis but also additional opportunity of successful venous anastomosis in the selected cases. The authors, therefore, propose this technique as an effective method for an alternative venous anastomosis in the zone I replantation.

  13. Virtual Incision Pattern Planning using Three-Dimensional Images for Optimization of Syndactyly Surgery

    Directory of Open Access Journals (Sweden)

    Inge A. Hoevenaren, MD

    2018-03-01

    Full Text Available Summary:. Syndactyly is a congenital condition characterized by fusion of the fingers. If not treated correctly during infancy, syndactyly may hinder the normal development of hand function. Many surgical techniques have been developed, with the main goal to create a functional hand with the smallest number of operative corrections. Therefore, exact preoperative planning of the reconstructive procedure is essential. An imaging method commonly used for preoperative planning is 3-dimensional (3D surface imaging. The goal of this study was to implement the use of this technique in hand surgery, by designing a virtual planning tool for a desyndactylization procedure based on 3D hand images. A 3D image of a silicon syndactyly model was made on which the incision pattern was virtually designed. A surgical template of this pattern was printed, placed onto the silicon model and delineated. The accuracy of the transfer from the virtual delineation toward the real delineation was calculated, resulting in a mean difference of 0.82 mm. This first step indicates that by using 3D images, a virtual incision pattern can be created and transferred back onto the patient successfully in an easy and accurate way by using a template. Thereafter, 3D hand images of 3 syndactyly patients were made, and individual virtual incision patterns were created. Each pattern was transferred onto the patient by using a 3D printed template. The resulting incision pattern needed minor modifications by the surgeon before the surgery was performed. Further research and validation are necessary to develop the virtual planning of desyndactylization procedures.

  14. The 'French Fry' VAC technique: hybridisation of traditional open wound NPWT with closed incision NPWT.

    Science.gov (United States)

    Chopra, Karan; Tadisina, Kashyap K; Singh, Devinder P

    2016-04-01

    Surgical site occurrences (SSO), specifically surgical site infections represent a significant burden in the US health care system. It has been hypothesised that postoperative dressing can help drive down SSO. We describe the successful use of a novel technique combining both closed incision and open negative pressure wound therapy in the management of a high-risk wound associated with lymphoedema of obesity. © 2014 The Authors. International Wound Journal © 2014 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  15. Gold-bearing fluvial and associated tidal marine sediments of Proterozoic age in the Mporokoso Basin, northern Zambia

    Science.gov (United States)

    Andrews-Speed, C. P.

    1986-07-01

    The structurally defined Mporokoso Basin contains up to 5000 m of continental and marine clastic sediments and minor silicic volcanics which together form the Mporokoso Group. These rocks overlie unconformably a basement of silicic-intermediate igneous rocks and accumulated within the interval 1830-1130 Ma. This sedimentological study was restricted to the eastern end of the basin and was part of an assessment of the potential for palaeoplacer gold in the Mporokoso Group. At the base of the Mporokoso Group, the Mbala Formation consists of 1000-1500 m of purple sandstones and conglomerates deposited in a braided-stream system overlain by 500-1000 m of mature quartz arenites deposited in a tidal marine setting. A general coarsening-upward trend exists within the fluvial sediments. Sandy, distal braided-stream facies passes upwards into more proximal conglomeratic facies. In proximal sections, poorly sorted conglomerates form the top of the coarsening-up sequence which is 500-700 m thick. The overlying fluvial sediments fine upwards. The tidal marine sandstones at the top of the Mbala Formation resulted from reworking of fluvial sediments during a marine transgression. Well-exposed sections with fluvial conglomerates were studied in detail. Individual conglomerate bodies form sheets extending for hundreds of metres downstream and at least one hundred metres across stream, with little sign of deep scouring or channelling. They are generally matrix-supported. The whole fluvial sequence is characterised by a paucity of mud or silt. These conglomerates were deposited by large velocity, sheet flows of water which transported a bed-load of pebbles and sand. Most fine material settling out from suspension was eroded by the next flow. The great lateral and vertical extent and the uniformity of the fluvial sediments suggest that the sediments accumulated over an unconfined alluvial plain and that the tectonic evolution of the source area was relatively continuous and not

  16. DNA polymerase. beta. reaction with ultraviolet-irradiated DNA incised by correndonuclease

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, R; Zarebska, Z [Instytut Onkologii, Warsaw (Poland); Zmudzka, B [Polska Akademia Nauk, Warsaw. Inst. Biochemii i Biofizyki

    1980-09-19

    Covalently closed circular Col E1 DNA was ultraviolet-irradiated with a dose of 60 J/m/sup 2/, thus introducing about 3.2 pyrimidine dimers per DNA molecule. Treatment of irradiated Col E1 DNA with Micrococcus luteus correndonuclease resulted, in the vicinity of pyrimidine dimers, in an average of 3.3 incisions per DNA molecule, and converted DNA to the open circular form. Incised Col E1 DNA stimulated no reaction with calf thymus DNA polymerase ..cap alpha.. but was recognized as a template by DNA polymerase ..beta... The latter enzyme incorporated about 1.6 molecules of dTMP (corresponding to 6 molecules of dNMP) per one correndonuclease incision. The length of the DNA polymerase ..beta.. product was comparable to the anticipated length of the DNA region within which the hydrogen bonds were disrupted owing to dimer formation. The enzyme required Mg/sup 2 +/ and four dNTPs for reaction and was resistant to N-ethylmaleimide or p-mercuribenzoate.

  17. The longitudinal epineural incision and complete nerve transection method for modeling sciatic nerve injury

    Directory of Open Access Journals (Sweden)

    Xing-long Cheng

    2015-01-01

    Full Text Available Injury severity, operative technique and nerve regeneration are important factors to consider when constructing a model of peripheral nerve injury. Here, we present a novel peripheral nerve injury model and compare it with the complete sciatic nerve transection method. In the experimental group, under a microscope, a 3-mm longitudinal incision was made in the epineurium of the sciatic nerve to reveal the nerve fibers, which were then transected. The small, longitudinal incision in the epineurium was then sutured closed, requiring no stump anastomosis. In the control group, the sciatic nerve was completely transected, and the epineurium was repaired by anastomosis. At 2 and 4 weeks after surgery, Wallerian degeneration was observed in both groups. In the experimental group, at 8 and 12 weeks after surgery, distinct medullary nerve fibers and axons were observed in the injured sciatic nerve. Regular, dense myelin sheaths were visible, as well as some scarring. By 12 weeks, the myelin sheaths were normal and intact, and a tight lamellar structure was observed. Functionally, limb movement and nerve conduction recovered in the injured region between 4 and 12 weeks. The present results demonstrate that longitudinal epineural incision with nerve transection can stably replicate a model of Sunderland grade IV peripheral nerve injury. Compared with the complete sciatic nerve transection model, our method reduced the difficulties of micromanipulation and surgery time, and resulted in good stump restoration, nerve regeneration, and functional recovery.

  18. Characteristics of Bone Injuries Resulting from Knife Wounds Incised with Different Forces.

    Science.gov (United States)

    Humphrey, Caitlin; Kumaratilake, Jaliya; Henneberg, Maciej

    2017-11-01

    The aim of this research was to experimentally determine the characteristics of incised bone wounds, which are commonly found in defense injuries. A specially constructed pivoting arm device was used to inflict wounds with controlled forces and direction. Five knives were selected to inflict the wounds on porcine forelimbs. Eight incised wounds were made per knife per force. A larger knife and a greater force caused longer and wider bone wounds. Comparisons of individual knives at the two forces produced varying results in the bone wounds. A correlation was seen between the force and the length (r = 0.69), width (r = 0.63), and depth (r = 0.57) of bone wounds. Serrated-edge and nonserrated knives can be distinguished from the appearance of the wound. The outcomes may be applicable in forensic investigations to ascertain the forces associated with incised wounds and identify the specific knife used. © 2017 American Academy of Forensic Sciences.

  19. Chemical weathering as a mechanism for the climatic control of bedrock river incision

    Science.gov (United States)

    Murphy, Brendan P.; Johnson, Joel P. L.; Gasparini, Nicole M.; Sklar, Leonard S.

    2016-04-01

    Feedbacks between climate, erosion and tectonics influence the rates of chemical weathering reactions, which can consume atmospheric CO2 and modulate global climate. However, quantitative predictions for the coupling of these feedbacks are limited because the specific mechanisms by which climate controls erosion are poorly understood. Here we show that climate-dependent chemical weathering controls the erodibility of bedrock-floored rivers across a rainfall gradient on the Big Island of Hawai‘i. Field data demonstrate that the physical strength of bedrock in streambeds varies with the degree of chemical weathering, which increases systematically with local rainfall rate. We find that incorporating the quantified relationships between local rainfall and erodibility into a commonly used river incision model is necessary to predict the rates and patterns of downcutting of these rivers. In contrast to using only precipitation-dependent river discharge to explain the climatic control of bedrock river incision, the mechanism of chemical weathering can explain strong coupling between local climate and river incision.

  20. Risk factors for an additional port in single-incision laparoscopic cholecystectomy in patients with cholecystitis.

    Science.gov (United States)

    Araki, Kenichiro; Shirabe, Ken; Watanabe, Akira; Kubo, Norio; Sasaki, Shigeru; Suzuki, Hideki; Asao, Takayuki; Kuwano, Hiroyuki

    2017-01-01

    Although single-incision laparoscopic cholecystectomy is now widely performed in patients with cholecystitis, some cases require an additional port to complete the procedure. In this study, we focused on risk factor of additional port in this surgery. We performed single-incision cholecystectomy in 75 patients with acute cholecystitis or after cholecystitis between 2010 and 2014 at Gunma University Hospital. Surgical indications followed the TG13 guidelines. Our standard procedure for single-incision cholecystectomy routinely uses two needlescopic devices. We used logistic regression analysis to identify the risk factors associated with use of an additional full-size port (5 or 10 mm). Surgical outcome was acceptable without biliary injury. Nine patients (12.0%) required an additional port, and one patient (1.3%) required conversion to open cholecystectomy because of severe adhesions around the cystic duct and common bile duct. In multivariate analysis, high C-reactive protein (CRP) values (>7.0 mg/dl) during cholecystitis attacks were significantly correlated with the need for an additional port (P = 0.009), with a sensitivity of 55.6%, specificity of 98.5%, and accuracy of 93.3%. This study indicated that the severe inflammation indicated by high CRP values during cholecystitis attacks predicts the need for an additional port. J. Med. Invest. 64: 245-249, August, 2017.

  1. Smaller incision size leads to higher predictability in microcoaxial cataract surgery.

    Science.gov (United States)

    Klamann, Matthias K J; Gonnermann, Johannes; Maier, Anna-Karina B; Torun, Necip; Bertelmann, Eckart

    2013-01-01

    The aim of the study was to compare the clinical outcomes of a 1.8 mm, 2.2 mm, and 2.75 mm microcoaxial cataract surgery system. METHODS. In this retrospective study, 129 eyes of 129 patients were included. Patients underwent phacoemulsification using a Stellaris system or an Infiniti system. The incision size was 1.8 mm, 2.2 mm, or 2.75 mm, respectively. Subjects were examined before surgery and 4 weeks after. The surgically induced astigmatism (SIA) was examined. The SIA in the 1.8 mm group was statistically lower compared to the 2.2 mm group (p=0.046) and the 2.75 mm group (p=0.017). There was no significant difference between the 2.2 mm group and the 2.75 mm group. With the use of appropriate support systems, 1.8 mm incisions appear to result in less SIA than 2.2 mm and 2.75 mm incisions. Advantages may arise from this, especially in the implantation of aspheric, toric, or multifocal lenses.

  2. Nd:YAG laser incision of the vesical neck in obstructive BPH

    Science.gov (United States)

    Gilbert, Peter T. O.

    2003-06-01

    From February, 1995 through June, 2002, 68 patients underwent laser incision of the prostate at our clinic. By means of a 23 F cytoscope and a 600 micrometer lateral firing quartz fiber the vesical neck was incised at the 5 and 7 o'clock position at 60 W power. Total energy averaged 13648 J. Operative time did not exceed 15 minutes. General anesthesia was employed in all but one patient. 38 patients remained catheter-free whereas 30 patients were catheterized for two hours. Except for three cases, all patients were discharged on the same day, usually after the first micturition. Anti-inflammatory treatment was administered for two weeks, Cotrimoxazole for 5 days. No serious complications were encountered. Minor side effects included urinary retention (1 pat.), urinary infection (3 pat.) and retrograde ejaculation (1 pat.). Considering a mean follow-up of 21 months, the average Qmax improved enormously (25.4 ml/s versus 10.9 ml/s), as did residual urine volume (35 ml versus 95 ml) and IPSS (7.1 versus 20.5). Three patients required TUR-P 2-3 years after laser surgery and one patient underwent radical retropubic prostatectomy for prostate cancer 2 years later. In conclusion, Nd:YAG laser incision of the prostate is a simple, safe, reliable and cost-effective outpatient procedure.

  3. Optical coherence tomography of the effects of stromal hydration on clear corneal incision architecture.

    Science.gov (United States)

    Calladine, Daniel; Tanner, Vaughan

    2009-08-01

    To evaluate the effects of stromal hydration on clear corneal incision (CCI) architecture immediately after surgery using anterior segment optical coherence tomography (AS-OCT). Department of Ophthalmology, Royal Berkshire Hospital, Reading, United Kingdom. Clear corneal incisions in adult eyes were examined using a Visante AS-OCT imaging system within 1 hour of surgery. Half the CCIs had stromal hydration with a balanced salt solution and half did not. Incisions were made with a 2.75 mm steel keratome. Intraocular pressure (IOP) was measured within 90 minutes after surgery. The CCI length and corneal thickness at the CCI site were measured using software built into the AS-OCT system. Thirty CCIs were evaluated. Stromal hydration significantly increased the measured CCI length (Pthe result of a trend toward increased corneal thickness at the CCI site with hydration (PThe mean CCI length was 1.69 mm +/- 0.27 (SD) (range 1.31 to 2.32 mm) with hydration and 1.51 +/- 0.23 mm (range 1.30 to 1.95 mm) without hydration. The mean IOP was 20.9 +/- 8.18 mm Hg and 15.8 +/- 8.20 mm Hg, respectively. The IOP tended to be higher with hydration (Pthe eye with a higher early postoperative IOP, showing the importance of taking stromal hydration into account when designing similar OCT studies of CCI architecture.

  4. No-Drain Single Incision Liposuction Pull-Through Technique for Gynecomastia.

    Science.gov (United States)

    Khalil, Ashraf A; Ibrahim, Amr; Afifi, Ahmed M

    2017-04-01

    Several different methods have been proposed for treatment of gynecomastia, depending on the amount of breast enlargement and skin redundancy. The liposuction pull-through technique has been proposed as an efficacious treatment for many gynecomastia cases. This work aims to study the outcome of this technique when applied as an outpatient procedure, without the use of drains and through a single incision. Fifty-two patients with bilateral gynecomastia without significant skin excess were included in this study. The liposuction pull-through technique was performed through a single incision just above the inframammary fold and without the use of drains. Patients were followed up for 6 months. The proposed technique was able to treat the gynecomastia in all patients, with a revision rate of 1.9% to remove residual glandular tissues. There were no seromas, hematomas, nipple distortion, permanent affection of nipple sensation or wound healing problems. The liposuction pull-through technique is an effective treatment for gynecomastia without significant skin redundancy. It combines the benefits of the direct excision of glandular tissues, with the minimally invasive nature of liposuction. Performing the procedure through a single incision without the use of drains and without general anesthesia is a safe alternative. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

  5. Gynecomastia: glandular-liposculpture through a single transaxillary one hole incision.

    Science.gov (United States)

    Lee, Yung Ki; Lee, Jun Hee; Kang, Sang Yoon

    2018-04-01

    Gynecomastia is characterized by the benign proliferation of breast tissue in men. Herein, we present a new method for the treatment of gynecomastia, using ultrasound-assisted liposuction with both conventional and reverse-cutting edge tip cannulas in combination with a pull-through lipectomy technique with pituitary forceps through a single transaxillary incision. Thirty patients were treated with this technique at the author's institution from January 2010 to January 2015. Ten patients were treated with conventional surgical excision of the glandular/fibrous breast tissue combined with liposuction through a periareolar incision before January 2010. Medical records, clinical photographs and linear analog scale scores were analyzed to compare the surgical results and complications. The patients were required to rate their cosmetic outcomes based on the linear analog scale with which they rated their own surgical results; the mean overall average score indicated a good or high level of satisfaction. There were no incidences of skin necrosis, hematoma, infection and scar contracture; however, one case each of seroma and nipple inversion did occur. Operative time was reduced overall using the new technique since it is relatively simple and straightforward. According to the evaluation by the four independent researchers, the patients treated with this new technique showed statistically significant improvements in scar and nipple-areolar complex (NAC) deformity compared to those who were treated using the conventional method. Glandular liposculpture through a single transaxillary incision is an efficient and safe technique that can provide aesthetically satisfying and consistent results.

  6. Distinction of infected and non-infected post-surgical incisions with In-111-WBC scintigraphy

    International Nuclear Information System (INIS)

    Abdel-Nabi, H.; Hinkle, G.H.; Olsen, J.O.

    1985-01-01

    To determine if In-111-WBCs scintigraphy can distinguish between healing and infection in post-surgical wounds, a prospective study was performed in patients with 3-14 day old surgical incisions. Eighteen patients (11 males and 7 females) were scanned 24 hrs after injection of 0.5 mCi of In-111 labeled autologous leukocytes. The scan findings were correlated with blood and/wound cultures results and diagnosis at time of discharge. Incisional uptake of In-111-WBCs was noted in 9 patients with infected surgical wounds and was absent in those 9 patients with non-infected surgical wounds. The results of the authors' study show that In-111-WBCs do not accumulate in non-infected surgical incisions. This confirms their previous findings in rats. The high specificity of In-111 leukocytes imaging makes it a valuable study in the evaluation of post-operative patients with suspected surgical wound infections. In-111 WBCs scintigraphy can distinguish between normal healing and infection at the site of recent (3-14 days) surgical incisions

  7. Disposable skin staplers for closure of linear gastrointestinal incisions in dogs.

    Science.gov (United States)

    Schwartz, Zeev; Coolman, Bradley R

    2018-02-01

    To report the clinical features and outcomes of linear gastrointestinal incisions closed with skin staples in dogs. Historical cohort study. 333 client-owned dogs. Medical records from 1 private referral hospital were searched for dogs that underwent gastrointestinal surgery between November 1999 and October 2015. Cases were included if skin staplers were used to close linear gastrointestinal incisions. Information regarding preoperative, surgical, and postoperative factors was collected. Complications were diagnosed in 8 of 245 (3.27%) dogs, including 3 of 245 (1.22%) dogs that died or were euthanized, 3 of 245 (1.22%) dogs with incisional dehiscence, and 2 of 245 (0.81%) dogs with attachment of a linear foreign body to the staples at the intestinal lumen. Dehiscence was noted at the enterotomy sites in 3 dogs at a mean time of 44 hours after surgery (SD ± 6.93). Two dogs presented with another linear foreign body that was attached to the staples in the intestinal lumen at postoperative days 24 and 42. The risk factors associated with incisional dehiscence included multiple gastrointestinal incisions performed in 1 surgery (χ 2 , P indication for surgical intervention, surgery location in the gastrointestinal tract, or surgeon experience and incisional dehiscence. Skin staplers provide safe and effective closure of gastrotomies, enterotomies, and colonotomies in dogs. This method is reliable, efficient, and affordable in the hands of veterinary surgeons with varying skill levels. © 2017 The American College of Veterinary Surgeons.

  8. Review of various liver retraction techniques in single incision laparoscopic surgery for the exposure of hiatus.

    Science.gov (United States)

    Palanivelu, Praveenraj; Patil, Kedar Pratap; Parthasarathi, Ramakrishnan; Viswambharan, Jaiganesh K; Senthilnathan, Palanisami; Palanivelu, Chinnusamy

    2015-01-01

    The main aspect of concern for upper GI procedures has been the retraction of the liver especially large left lobes as commonly encountered in Bariatric surgery. Not doing so would compromise the view of the hiatus, hence theoretically reducing the quality of the surgery and increasing the possibility of complications. The aim of this study was to review the various liver retraction techniques in single incision surgery being done at our institute and analyze them. A retrospective study of the various techniques and a subsequent analysis was made based on advantages and disadvantages of each method. Objectively a quantitative measure of hiatal exposure was done using a scoring system based on the grade of exposure after reviewing the surgical videos. From January 2011 to January 2013 total 104 patients underwent single incision surgery with the various liver retraction techniques with following grades of exposure -liver suspension tube technique with naso gastric tubing (2.11) and with corrugated drain (2.09) needlescopic method (1.2), Umbilical tape sling (1.95), crural stitch method (2.5). Needeloscopic method has the best grade of exposure and is the easiest to start with. The average time to create the liver retraction was 2.8 to 8.6 min.There was no procedure related morbidity or mortality. The mentioned liver retraction techniques are cost effective and easy to learn. We recommend using these techniques to have a good exposure of hiatus, without compromising the safety of surgery in single incision surgery.

  9. Gully annealing by fluvially-sourced Aeolian sand: remote sensing investigations of connectivity along the Fluvial-Aeolian-hillslope continuum on the Colorado River

    Science.gov (United States)

    Sankey, Joel B.; East, Amy E.; Collins, Brian D.; Caster, Joshua J.

    2015-01-01

    Processes contributing to development of ephemeral gully channels are of great importance to landscapes worldwide, and particularly in dryland regions where soil loss and land degradation from gully erosion pose long-term, land-management problems. Whereas gully formation has been relatively well studied, much less is known of the processes that anneal gullies and impede their growth. This work investigates gully annealing by aeolian sediment, along the Colorado River downstream of Glen Canyon Dam in Glen, Marble, and Grand Canyons, Arizona, USA (Figure 1). In this segment of the Colorado River, gully erosion potentially affects the stability and preservation of archaeological sites that are located within valley margins. Gully erosion occurs as a function of ephemeral, rainfall-induced overland flow associated with intense episodes of seasonal precipitation. Measurements of sediment transport and topographic change have demonstrated that fluvial sand in some locations is transported inland and upslope by aeolian processes to areas affected by gully erosion, and aeolian sediment activity can be locally effective at counteracting gully erosion (Draut, 2012; Collins and others, 2009, 2012; Sankey and Draut, 2014). The degree to which specific locations are affected by upslope wind redistribution of sand from active channel sandbars to higher elevation valley margins is termed “connectivity”. Connectivity is controlled spatially throughout the river by (1) the presence of upwind sources of fluvial sand within the contemporary active river channel (e.g., sandbars), and (2) bio-physical barriers that include vegetation and topography that might impede aeolian sediment transport. The primary hypothesis of this work is that high degrees of connectivity lead to less gullying potential.

  10. Cervical and incisal marginal discrepancy in ceramic laminate veneering materials: A SEM analysis

    Directory of Open Access Journals (Sweden)

    Hemalatha Ranganathan

    2017-01-01

    Full Text Available Context: Marginal discrepancy influenced by the choice of processing material used for the ceramic laminate veneers needs to be explored further for better clinical application. Aims: This study aimed to evaluate the amount of cervical and incisal marginal discrepancy associated with different ceramic laminate veneering materials. Settings and Design: This was an experimental, single-blinded, in vitro trial. Subjects and Methods: Ten central incisors were prepared for laminate veneers with 2 mm uniform reduction and heavy chamfer finish line. Ceramic laminate veneers fabricated over the prepared teeth using four different processing materials were categorized into four groups as Group I - aluminous porcelain veneers, Group II - lithium disilicate ceramic veneers, Group III - lithium disilicate-leucite-based veneers, Group IV - zirconia-based ceramic veneers. The cervical and incisal marginal discrepancy was measured using a scanning electron microscope. Statistical Analysis Used: ANOVA and post hoc Tukey honest significant difference (HSD tests were used for statistical analysis. Results: The cervical and incisal marginal discrepancy for four groups was Group I - 114.6 ± 4.3 μm, 132.5 ± 6.5 μm, Group II - 86.1 ± 6.3 μm, 105.4 ± 5.3 μm, Group III - 71.4 ± 4.4 μm, 91.3 ± 4.7 μm, and Group IV - 123.1 ± 4.1 μm, 142.0 ± 5.4 μm. ANOVA and post hoc Tukey HSD tests observed a statistically significant difference between the four test specimens with regard to cervical marginal discrepancy. The cervical and incisal marginal discrepancy scored F = 243.408, P < 0.001 and F = 180.844, P < 0.001, respectively. Conclusion: This study concluded veneers fabricated using leucite reinforced lithium disilicate exhibited the least marginal discrepancy followed by lithium disilicate ceramic, aluminous porcelain, and zirconia-based ceramics. The marginal discrepancy was more in the incisal region than in the cervical region in all the groups.

  11. High transverse skin incisions may reduce wound complications in obese women having cesarean sections: a pilot study.

    Science.gov (United States)

    Walton, Robert B; Shnaekel, Kelsey L; Ounpraseuth, Songthip T; Napolitano, Peter G; Magann, Everett F

    2017-11-01

    Women having cesarean section have a high risk of wound complications. Our objective was to determine whether high transverse skin incisions are associated with a reduced risk of cesarean wound complications in women with BMI greater than 40. A retrospective cohort study was undertaken of parturients ages 18-45 with BMI greater than 40 having high transverse skin incisions from January 2010 to April 2015 at a tertiary maternity hospital. Temporally matched controls had low transverse skin incisions along with a BMI greater than 40. The primary outcome, wound complication, was defined as any seroma, hematoma, dehiscence, or infection requiring opening and evacuating/debriding the wound. Secondary outcomes included rates of endometritis, number of hospital days, NICU admission, Apgar scores, birth weight, and gestational age at delivery. Analysis of outcomes was performed using two-sample t-test or Wilcoxon rank-sum test for continuous variables and Fisher's exact test for categorical variables. Thirty-two women had high transverse incisions and were temporally matched with 96 controls (low transverse incisions). The mean BMI was 49 for both groups. There was a trend toward reduced wound complications in those having high transverse skin incisions, but this did not reach statistical significance (15.63% versus 27.08%, p = .2379). Those having high transverse skin incisions had lower five minute median Apgar scores (8.0 versus 9.0, p = .0021), but no difference in umbilical artery pH values. The high transverse group also had increased NICU admissions (28.13% versus 5.21%, p = .0011), and early gestational age at delivery (36.8 versus 38.0, p = .0272). High transverse skin incisions may reduce the risk of wound complications in parturients with obesity. A study with more power should be considered.

  12. Three-dimensional observations of the incisive canal and the surrounding bone using cone-beam computed tomography

    International Nuclear Information System (INIS)

    Asaumi, Rieko; Kawai, Taisuke; Sato, Iwao; Yoshida, Shunji; Yosue, Takashi

    2010-01-01

    The shape of the anterior region of the maxilla is critical when planning implant treatment. The purpose of the present study was to assess the typical morphology of the incisive canal and surrounding bone. In total, 70 maxillae of Japanese dry skulls were used after being divided into dentate and edentulous groups. Cone-beam computed tomography (CBCT) images of the maxilla were acquired by using standardized methods. Using the anterior nasal spine as a reference point, the change in position was measured and analyzed statistically. Also, three-dimensional (3-D) images of the incisive canal were classified into five subsets: cylinder, groove, penetration, bifurcation at the superior portion, and bifurcation at the inferior portion. The quantity of alveolar bone in the incisor region was greatly reduced from the alveolar ridge and labial surface. Moreover, the vertical position of the incisive foramen was significantly (P<0.05) superior in the edentulous groups. Regarding the classification of maxillae by the 3-D shape of the incisive canal, many canals were cylindrical. Horizontal bone reduction from the labial side and vertical bone reduction from the alveolar crest were conspicuous; thus, the angle of the anterior alveolar bone changed after the loss of teeth. The incisive canal diameter in the edentulous group was larger than in the dentate group. The nondestructive assessment of the incisive canals and surrounding bone with CBCT showed two typical shapes for the presence or absence of the incisors. These findings indicate the importance of image diagnosis before esthetic restoration. (author)

  13. [EFFECTIVENESS OF ADVANCED SKIN FLAP AND V-SHAPED VENTRAL INCISION ALONG THE ROOT OF PENILE SHAFT FOR CONCEALED PENIS].

    Science.gov (United States)

    Lin, Junshan; Li, Dumiao; Zhang, Jianxing; Wu, Qiang; Xu, Yali; Lin, Li

    2015-09-01

    To investigate effectiveness of advanced skin flap and V-shaped ventral incision along the root of penile shaft for concealed penis in children. Between July 2007 and January 2015, 121 boys with concealed penis were treated with advanced skin flap and V-shaped ventral incision along the root of penile shaft. The age varied from 18 months to 13 years (mean, 7.2 years). Repair was based on a vertical incision in median raphe, complete degloving of penis and tacking its base to the dermis of the skin. Advanced skin flap and a V-shaped ventral incision along the root of penile shaft were used to cover the penile shaft. The operation time ranged from 60 to 100 minutes (mean, 75 minutes). Disruption of wound occurred in 1 case, and was cured after dressing change; and primary healing of incision was obtained in the others. The follow-up period ranged from 3 months to 7 years (median, 24 months). All patients achieved good to excellent cosmetic results with a low incidence of complications. The results were satisfactory in exposure of penis and prepuce appearance. No obvious scar was observed. The penis had similar appearance to that after prepuce circumcision. A combination of advanced skin flap and V-shaped ventral incision along the root of penile shaft is a simple, safe, and effective procedure for concealed penis with a similar appearance result to the prepuce circumcision.

  14. A new ‘superassemblage’ model explaining proximal-to-distal and lateral facies changes in fluvial environments, based on the Proterozoic Sanjauli Formation (Lesser Himalaya, India

    Directory of Open Access Journals (Sweden)

    Ananya Mukhopadhyay

    2016-09-01

    Full Text Available Facies analysis of fluvial deposits of the Proterozoic Sanjauli Formation in the Lesser Himalaya was combined with an architectural analysis. On this basis, a model was developed that may be applied to other fluvial systems as well, whether old or recent. The new model, which might be considered as an assemblage of previous models, explains lateral variations in architecture and facies but is not in all respects consistent with the standard fluvial models. The Sanjauli fluvial model is unique in that it deals with lateral facies variations due to shifts of the base-level along with fluctuations in accommodation space owing to changes in palaeoclimate.

  15. Fluvial particle characterization using artificial neural network and spectral image processing

    Science.gov (United States)

    Shrestha, Bim Prasad; Gautam, Bijaya; Nagata, Masateru

    2008-03-01

    Sand, chemical waste, microbes and other solid materials flowing with the water bodies are of great significance to us as they cause substantial impact to different sectors including drinking water management, hydropower generation, irrigation, aquatic life preservation and various other socio-ecological factors. Such particles can't completely be avoided due to the high cost of construction and maintenance of the waste-treatment methods. A detailed understanding of solid particles in surface water system can have benefit in effective, economic, environmental and social management of water resources. This paper describes an automated system of fluvial particle characterization based on spectral image processing that lead to the development of devices for monitoring flowing particles in river. Previous research in coherent field has shown that it is possible to automatically classify shapes and sizes of solid particles ranging from 300-400 μm using artificial neural networks (ANN) and image processing. Computer facilitated with hyper spectral and multi spectral images using ANN can further classify fluvial materials into organic, inorganic, biodegradable, bio non degradable and microbes. This makes the method attractive for real time monitoring of particles, sand and microorganism in water bodies at strategic locations. Continuous monitoring can be used to determine the effect of socio-economic activities in upstream rivers, or to monitor solid waste disposal from treatment plants and industries or to monitor erosive characteristic of sand and its contribution to degradation of efficiency of hydropower plant or to identify microorganism, calculate their population and study the impact of their presence. Such system can also be used to characterize fluvial particles for planning effective utilization of water resources in micro-mega hydropower plant, irrigation, aquatic life preservation etc.

  16. Study on fine geological modelling of the fluvial sandstone reservoir in Daqing oilfield

    Energy Technology Data Exchange (ETDEWEB)

    Zhoa Han-Qing [Daqing Research Institute, Helongjiang (China)

    1997-08-01

    These paper aims at developing a method for fine reservoir description in maturing oilfields by using close spaced well logging data. The main productive reservoirs in Daqing oilfield is a set of large fluvial-deltaic deposits in the Songliao Lake Basin, characterized by multi-layers and serious heterogeneities. Various fluvial channel sandstone reservoirs cover a fairly important proportion of reserves. After a long period of water flooding, most of them have turned into high water cut layers, but there are considerable residual reserves within them, which are difficult to find and tap. Making fine reservoir description and developing sound a geological model is essential for tapping residual oil and enhancing oil recovery. The principal reason for relative lower precision of predicting model developed by using geostatistics is incomplete recognition of complex distribution of fluvial reservoirs and their internal architecture`s. Tasking advantage of limited outcrop data from other regions (suppose no outcrop data available in oilfield) can only provide the knowledge of subtle changing of reservoir parameters and internal architecture. For the specific geometry distribution and internal architecture of subsurface reservoirs (such as in produced regions) can be gained only from continuous infilling logging well data available from studied areas. For developing a geological model, we think the first important thing is to characterize sandbodies geometries and their general architecture`s, which are the framework of models, and then the slight changing of interwell parameters and internal architecture`s, which are the contents and cells of the model. An excellent model should possess both of them, but the geometry is the key to model, because it controls the contents and cells distribution within a model.

  17. Effects of Wildfire on Fluvial Sediment Regime through Perturbations in Dry-Ravel

    Science.gov (United States)

    Florsheim, J. L.; Chin, A.; Kinoshita, A. M.; Nourbakhshbeidokhti, S.; Storesund, R.; Keller, E. A.

    2015-12-01

    In steep chaparral ecosystems with Mediterranean climate, dry ravel is a natural process resulting from wildfire disturbance that supplies sediment to fluvial systems. When dense chaparral vegetation burns, sediment accumulated on steep hillslopes is released for dry-season transport (dry ravel) down steep hillslopes during or soon after the wildfire. Results of a field study in southern California's Transverse Ranges illustrate the effect of wildfire on fluvial sediment regime in an unregulated chaparral system. Big Sycamore Canyon in the steep Santa Monica Mountains burned during the May 2013 Springs Fire and experienced one small sediment-transporting stormflow during the following winter. We conducted pre- and post-storm field campaigns during the fall and winter following the fire to quantify the effect of wildfire on the fluvial sediment regime. We utilized a sediment mass balance approach in which: 1) sediment supply, consisting primarily of dry ravel-derived deposits composed of relatively fine grained-sediment, was measured in the upstream basin and in the hillslope-channel margin adjacent to the study reach; 2) changes in storage in the study reach were quantified by analyzing the difference between pre- and post-storm channel topography derived from Terrestrial LiDAR Scanning (TLS) and field surveys; and 3) transport from the study reach was estimated as the difference between supply and change in storage where uncertainty is estimated using calculated sediment transport as a comparison. Results demonstrate channel deposition caused by changes in the short-term post-wildfire sediment regime. The increased sediment supply and storage are associated with significant changes in morphology, channel bed-material characteristics, and ecology. These results suggest that dry-ravel processes are an important factor to consider in post-wildfire sediment management.

  18. Detrital shadows: estuarine food web connectivity depends on fluvial influence and consumer feeding mode.

    Science.gov (United States)

    Howe, Emily; Simenstad, Charles A; Ogston, Andrea

    2017-10-01

    We measured the influence of landscape setting on estuarine food web connectivity in five macrotidal Pacific Northwest estuaries across a gradient of freshwater influence. We used stable isotopes (δ 13 C, δ 15 N, δ 34 S) in combination with a Bayesian mixing model to trace primary producer contributions to suspension- and deposit-feeding bivalve consumers (Mytilus trossulus and Macoma nasuta) transplanted into three estuarine vegetation zones: emergent marsh, mudflat, and eelgrass. Eelgrass includes both Japanese eelgrass (Zostera japonica) and native eelgrass (Zostera marina). Fluvial discharge and consumer feeding mode strongly influenced the strength and spatial scale of observed food web linkages, while season played a secondary role. Mussels displayed strong cross-ecosystem connectivity in all estuaries, with decreasing marine influence in the more fluvial estuaries. Mussel diets indicated homogenization of detrital sources within the water column of each estuary. In contrast, the diets of benthic deposit-feeding clams indicated stronger compartmentalization in food web connectivity, especially in the largest river delta where clam diets were trophically disconnected from marsh sources of detritus. This suggests detritus deposition is patchy across space, and less homogenous than the suspended detritus pool. In addition to fluvial setting, other estuary-specific environmental drivers, such as marsh area or particle transport speed, influenced the degree of food web linkages across space and time, often accounting for unexpected patterns in food web connectivity. Transformations of the estuarine landscape that alter river hydrology or availability of detritus sources can thus potentially disrupt natural food web connectivity at the landscape scale, especially for sedentary organisms, which cannot track their food sources through space. © 2017 by the Ecological Society of America.

  19. Characterizing Feedbacks Between Environmental Forcing and Sediment Characteristics in Fluvial and Coastal Systems

    Science.gov (United States)

    Feehan, S.; Ruggiero, P.; Hempel, L. A.; Anderson, D. L.; Cohn, N.

    2016-12-01

    Characterizing Feedbacks Between Environmental Forcing and Sediment Characteristics in Fluvial and Coastal Systems American Geophysical Union, 2016 Fall Meeting: San Francisco, CA Authors: Scott Feehan, Peter Ruggiero, Laura Hempel, and Dylan Anderson Linking transport processes and sediment characteristics within different environments along the source to sink continuum provides critical insight into the dominant feedbacks between grain size distributions and morphological evolution. This research is focused on evaluating differences in sediment size distributions across both fluvial and coastal environments in the U.S. Pacific Northwest. The Cascades' high relief is characterized by diverse flow regimes with high peak/flashy flows and sub-threshold flows occurring in relative proximity and one of the most energetic wave climates in the world. Combining analyses of both fluvial and coastal environments provides a broader understanding of the dominant forces driving differences between each system's grain size distributions, sediment transport processes, and resultant evolution. We consider sediment samples taken during a large-scale flume experiment that simulated floods representative of both high/flashy peak flows analogous to runoff dominated rivers and sub-threshold flows, analogous to spring-fed rivers. High discharge flows resulted in narrower grain size distributions while low flows where less skewed. Relative sediment size showed clear dependence on distance from source and the environments' dominant fluid motion. Grain size distributions and sediment transport rates were also quantified in both wave dominated nearshore and aeolian dominated backshore portions of Long Beach Peninsula, Washington during SEDEX2, the Sandbar-aEolian-Dune EXchange Experiment of summer 2016. The distributions showed spatial patterns in mean grain size, skewness, and kurtosis dependent on the dominant sediment transport process. The feedback between these grain size

  20. The legacy of lead (Pb) in fluvial bed sediments of an urban drainage basin, Oahu, Hawaii.

    Science.gov (United States)

    Hotton, Veronica K; Sutherland, Ross A

    2016-03-01

    The study of fluvial bed sediments is essential for deciphering the impact of anthropogenic activities on water quality and drainage basin integrity. In this study, a systematic sampling design was employed to characterize the spatial variation of lead (Pb) concentrations in bed sediment of urban streams in the Palolo drainage basin, southeastern Oahu, Hawaii. Potentially bioavailable Pb was assessed with a dilute 0.5 N HCl extraction of the  Pukele (19) > Waiomao (8). Comparisons to sediment quality guidelines and potential toxicity estimates using a logistic regression model (LRM) indicated a significant potential risk of Palolo Stream bed sediments to bottom-dwelling organisms.

  1. Fluvial sediments characterization of Hornád river in its chosen parts (preliminary study

    Directory of Open Access Journals (Sweden)

    Stela Hanigovská

    2008-12-01

    Full Text Available Knowledge of main river sedimentary characteristics is very important source of information for next study or potentialcommercial usage of fluvial sediments. In paper is shown characterization of sediment distribution in chosen part of the river Hornád.Three main facial types were studied and described – gravel, sand and clay. Model created in this study shows that Hornád is a riverwith predominant gravel transport. This model also shows a sufficient amount of gravel for commercial use in some parts of the river.

  2. Controles fluviales del Rio Cauca en la región de La Mojana.

    OpenAIRE

    Posada García, Lilian; Rhenals Garrido, Remberto Luis

    2006-01-01

    Se realiza un análisis de fotografías aéreas, imágenes de satélite y cartografía de diferentes años que permiten identificar procesos importantes de divagación, erosión y sedimentación de la zona estudiada. La variación con el tiempo de las formas del canal (islas y barras), la aparición de complejos de orillares, madreviejas (canales abandonados y sedimentados), canales abandonados, cambios de curso del canal principal, entre otros procesos muestran la gran dinámica fluvial del sistema....

  3. Determination of burial dose in incompletely bleached fluvial samples using single grains of quartz

    DEFF Research Database (Denmark)

    Thomsen, Kristina Jørkov; Murray, A.S.; Bøtter-Jensen, Lars

    2007-01-01

    We determine the burial dose in three known-age incompletely bleached fluvial samples using single grains of quartz. Estimation of burial dose in incompletely bleached samples requires that the characteristics of the well-bleached part of the distribution are known in order to distinguish between...... well-bleached and poorly bleached grains. It is especially important to investigate if the uncertainties assigned to individual estimates of dose adequately describe the observed variability in well-bleached dose distributions. We investigate this by quantifying the overdispersion in laboratory-bleached...

  4. Analysis of Fluvial Bed Sediments Along the Apalachicola River, Florida through Field Reconnaissance Studies

    Science.gov (United States)

    Passeri, D.; Hagen, S. C.; Daranpob, A.; Smar, D. E.

    2011-12-01

    River competence is an important parameter in understanding sediment transport in fluvial systems. Competence is defined as the measure of a stream's ability to transport a certain maximum grain size of sediment. Studies have shown that bed sediment particle size in rivers and streams tends to vary spatially along the direction of stream flow. Over a river section several reaches long, variability of sediment particle sizes can be seen, often becoming finer downstream. This phenomenon is attributed to mechanisms such as local control of stream gradient, coarse tributary sediment supply or particle breakdown. Average particle size may also be smaller in tributary sections of rivers due to river morphology. The relationship between river mean velocity and particle size that can be transported has also been explored. The Hjulstrom curve classifies this relationship by relating particle size to velocity, dividing the regions of sedimentation, transportation, and erosion. The curve can also be used to find values such as the critical erosion velocity (the velocity required to transport particles of various sizes in suspension) and settling velocity (the velocity at which particles of a given size become too heavy to be transported and fall out of suspension, consequently causing deposition). The purpose of this research is to explore the principles of river competence through field reconnaissance collection and laboratory analysis of fluvial sediment core samples along the Apalachicola River, FL and its distributaries. Sediment core samples were collected in the wetlands and estuarine regions of the Apalachicola River. Sieve and hydrometer analyses were performed to determine the spatial distribution of particle sizes along the river. An existing high resolution hydrodynamic model of the study domain was used to simulate tides and generate river velocities. The Hjulstrom curve and the generated river velocities were used to define whether sediment was being transported

  5. A fast, parallel algorithm to solve the basic fluvial erosion/transport equations

    Science.gov (United States)

    Braun, J.

    2012-04-01

    Quantitative models of landform evolution are commonly based on the solution of a set of equations representing the processes of fluvial erosion, transport and deposition, which leads to predict the geometry of a river channel network and its evolution through time. The river network is often regarded as the backbone of any surface processes model (SPM) that might include other physical processes acting at a range of spatial and temporal scales along hill slopes. The basic laws of fluvial erosion requires the computation of local (slope) and non-local (drainage area) quantities at every point of a given landscape, a computationally expensive operation which limits the resolution of most SPMs. I present here an algorithm to compute the various components required in the parameterization of fluvial erosion (and transport) and thus solve the basic fluvial geomorphic equation, that is very efficient because it is O(n) (the number of required arithmetic operations is linearly proportional to the number of nodes defining the landscape), and is fully parallelizable (the computation cost decreases in a direct inverse proportion to the number of processors used to solve the problem). The algorithm is ideally suited for use on latest multi-core processors. Using this new technique, geomorphic problems can be solved at an unprecedented resolution (typically of the order of 10,000 X 10,000 nodes) while keeping the computational cost reasonable (order 1 sec per time step). Furthermore, I will show that the algorithm is applicable to any regular or irregular representation of the landform, and is such that the temporal evolution of the landform can be discretized by a fully implicit time-marching algorithm, making it unconditionally stable. I will demonstrate that such an efficient algorithm is ideally suited to produce a fully predictive SPM that links observationally based parameterizations of small-scale processes to the evolution of large-scale features of the landscapes on

  6. Transverse Skin Crease versus Vertical Midline Incision versus Laparoscopy for Right Hemicolectomy: A Systematic Review—Current Status of Right Hemicolectomy

    Directory of Open Access Journals (Sweden)

    Alberto Santoro

    2014-01-01

    Full Text Available Purpose. The right hemicolectomy may be conducted through laparoscopic or laparotomic surgery, transverse or midline incisions. The transverse laparotomy offers some advantages compared to the midline laparotomy and laparoscopy. A literature review was performed to evaluate the possible advantages of the transverse incision versus midline incision or laparoscopic right hemicolectomy. Methods. A systematic research was performed in Medline, Embase, Cochrane Central Register of Controlled Trials, CINAHL, BioMed Central, and the Science Citation Index. Results. Laparotomic right hemicolectomy with transverse incision is preferable to laparotomic hemicolectomy with midline incision. A transverse incision offers a lessened postoperative pain following physical activity, a lessened need to administer analgesic therapy during the post-operative time, better aesthetic results, and a better post-operative pulmonary function. Open surgery with transverse or midline incision ensured a shorter operative time, lower costs and a greater length of the incision compared to the laparoscopic. However, there are no differences in the oncological outcomes. Conclusions. It was not possible to identify significant differences between the open right hemicolectomy with transverse incision versus the open right hemicolectomy with midline incision or laparoscopic hemicolectomy.

  7. [Antero-medial incision of knee joint for the treatment of intercondylar fracture of femur].

    Science.gov (United States)

    Yin, Zi-Fei; Sun, Bin-Feng; Yang, Xiao-Hai; Wang, Qing; Qian, Ping-Kang; Wu, Xiao-Feng; Xu, Feng

    2017-12-25

    To explore the clinical effect of antero-medial incision of knee joint in treating intercondylar fracture of femur. From September 2012 to March 2015, 24 patients with intercondylar fracture of femur were selected, including 17 males and 7 females, aged from 20 to 65 years old with an average of(38.3±9.5) years old. Among them, 12 cases were caused by traffic accident, 8 cases were caused by falling injury and 4 cases were caused by falling down. All patients were closed fractures. The time from injury to hospital was from 30 min to 8 h with an average of(2.2±0.3) h. According to AO classification, 4 cases were type B1, 3 type B2, 2 type B3, 5 type C1, 6 type C2 and 4 type C3. All patients were treated with antero-medial incision of knee joint. Operative time, blood loss and postoperative complications were observed and recovery of keen function was evaluated by Kolmert scoring. All patients were followed-up from 6 to 12 months with average of (9.0±1.7) months. Operative time ranged from 50 to 90 min with an average of (70.0±8.2) min; blood loss ranged from 90 to 400 ml with an average of (180±36) ml; negative pressure flow was from 30 to 90 ml, with an average of (50.0±7.1) ml. All fracture were healed at stage I without loosening of internal fixator, fracture nonunion, and deep vein thrombosis. According to Kolmert scoring, 16 patients got excellent result, 5 patients good and 3 fair. Antero-medial incision of knee joint in treating intercondylar fracture of femur, which has advantages of good fracture reduction, less injury of soft tissue and simple operation, could obtain good clinical results.

  8. Incisal tooth wear and self-reported TMD pain in children and adolescents.

    Science.gov (United States)

    Hirsch, Christian; John, Mike T; Lobbezoo, Frank; Setz, Juergen M; Schaller, Hans-Guenter

    2004-01-01

    Incisal tooth wear may be a sign of long-term bruxing behavior. Bruxism is purported to be a risk factor for temporomandibular disorders (TMD). The aim of this population-based cross-sectional study was to determine if anterior tooth wear is associated with the self-report of TMD pain in children and adolescents. In a population sample of 1,011 children and adolescents (mean age 13.1 years, range 10 to 18 years; female 52%; response rate 85%), TMD cases were defined as subjects reporting pain in the face, jaw muscles, and temporomandibular joint during the last month according to RDC/TMD. All other subjects were considered controls. Incisal tooth wear was assessed in the clinical examination using a 0 to 2 scale (no wear, enamel wear, dentin wear) for every anterior permanent tooth. The mean wear score for the individuals was categorized into 0, 0.01 to 0.20, 0.21 to 0.40, and 0.41+. A multiple logistic regression analysis, controlling for the effects of age and gender, analyzed the association between the categorized summary wear score and TMD. Specifically, the hypothesis of a trend between higher tooth wear scores and higher risk of TMD was tested. An odds ratio of 1.1 indicated, after adjusting for gender and age, no statistically significantly higher risk of TMD pain with higher tooth wear scores. Incisal tooth wear was not associated with self-reported TMD pain in 10- to 18-year-old subjects.

  9. Review of various liver retraction techniques in single incision laparoscopic surgery for the exposure of hiatus

    Directory of Open Access Journals (Sweden)

    Praveenraj Palanivelu

    2015-01-01

    Full Text Available Background: The main aspect of concern for upper GI procedures has been the retraction of the liver especially large left lobes as commonly encountered in Bariatric surgery. Not doing so would compromise the view of the hiatus, hence theoretically reducing the quality of the surgery and increasing the possibility of complications. The aim of this study was to review the various liver retraction techniques in single incision surgery being done at our institute and analyze them. Material and Methods: A retrospective study of the various techniques and a subsequent analysis was made based on advantages and disadvantages of each method. Objectively a quantitative measure of hiatal exposure was done using a scoring system based on the grade of exposure after reviewing the surgical videos. From January 2011 to January 2013 total 104 patients underwent single incision surgery with the various liver retraction techniques with following grades of exposure -liver suspension tube technique with naso gastric tubing (2.11 and with corrugated drain (2.09 needlescopic method (1.2, Umbilical tape sling (1.95, crural stitch method (2.5. Needeloscopic method has the best grade of exposure and is the easiest to start with. The average time to create the liver retraction was 2.8 to 8.6 min.There was no procedure related morbidity or mortality. Conclusions: The mentioned liver retraction techniques are cost effective and easy to learn. We recommend using these techniques to have a good exposure of hiatus, without compromising the safety of surgery in single incision surgery.

  10. Anguilles estuariennes et fluviales : apports de l'otolithométrie

    Directory of Open Access Journals (Sweden)

    MOUNAIX B.

    1994-10-01

    La zonation de l'otolithe, interprétée par rapport à la croissance des poissons, décrit deux écotypes dans la population d'anguilles de la Vilaine : un écotype fluvial dont la croissance est perturbée et ralentie, et un écotype estuarien dont la croissance est plus régulière. Cette partition de la population est cohérente avec les caractéristiques environnementales des deux milieux. Elle pourrait par ailleurs constituer un indice de l'impact des aménagements des bassins versants sur la croissance, la durée du cycle biologique et la dynamique des populations d'anguilles. Il apparaît alors nécessaire de considérer séparément les sous-unités estuariennes et fluviales des stocks d'anguilles des bassins versants de la Vilaine et de la Loire, en particulier pour étudier la diminution des abondances.

  11. MODELLING LANDSCAPE MORPHODYNAMICS BY TERRESTRIAL PHOTOGRAMMETRY: AN APPLICATION TO BEACH AND FLUVIAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    E. Sánchez-García

    2016-06-01

    Full Text Available Beach and fluvial systems are highly dynamic environments, being constantly modified by the action of different natural and anthropic phenomena. To understand their behaviour and to support a sustainable management of these fragile environments, it is very important to have access to cost-effective tools. These methods should be supported on cutting-edge technologies that allow monitoring the dynamics of the natural systems with high periodicity and repeatability at different temporal and spatial scales instead the tedious and expensive field-work that has been carried out up to date. The work herein presented analyses the potential of terrestrial photogrammetry to describe beach morphology. Data processing and generation of high resolution 3D point clouds and derived DEMs is supported by the commercial Agisoft PhotoScan. Model validation is done by comparison of the differences in the elevation among the photogrammetric point cloud and the GPS data along different beach profiles. Results obtained denote the potential that the photogrammetry 3D modelling has to monitor morphological changes and natural events getting differences between 6 and 25 cm. Furthermore, the usefulness of these techniques to control the layout of a fluvial system is tested by the performance of some modeling essays in a hydraulic pilot channel.

  12. Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

    Directory of Open Access Journals (Sweden)

    R. R. Pawson

    2008-03-01

    Full Text Available This study investigates for the first time the relative importance of dissolved organic carbon (DOC and particulate organic carbon (POC in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

  13. A conceptual connectivity framework for understanding geomorphic change in human-impacted fluvial systems

    Science.gov (United States)

    Pöppl, Ronald; Keesstra, Saskia; Maroulis, Jerry

    2017-04-01

    Human-induced landscape change is difficult to predict due to the complexity inherent in both geomorphic and social systems as well as due to emerging coupling relationships between them. To better understand system complexity and system response to change, connectivity has become an important research paradigm within various disciplines including geomorphology, hydrology and ecology. With the proposed conceptual connectivity framework on geomorphic change in human-impacted fluvial systems a cautionary note is flagged regarding the need (i) to include and to systematically conceptualise the role of different types of human agency in altering connectivity relationships in geomorphic systems and (ii) to integrate notions of human-environment interactions to connectivity concepts in geomorphology to better explain causes and trajectories of landscape change. Underpinned by case study examples, the presented conceptual framework is able to explain how geomorphic response of fluvial systems to human disturbance is determined by system-specific boundary conditions (incl. system history, related legacy effects and lag times), vegetation dynamics and human-induced functional relationships (i.e. feedback mechanisms) between the different spatial dimensions of connectivity. It is further demonstrated how changes in social systems can trigger a process-response feedback loop between social and geomorphic systems that further governs the trajectory of landscape change in coupled human-geomorphic systems.

  14. Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

    Science.gov (United States)

    Evans, Chris D.; Page, Susan E.; Jones, Tim; Moore, Sam; Gauci, Vincent; Laiho, Raija; Hruška, Jakub; Allott, Tim E. H.; Billett, Michael F.; Tipping, Ed; Freeman, Chris; Garnett, Mark H.

    2014-11-01

    Carbon sequestration and storage in peatlands rely on consistently high water tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but with marked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (use changes in the tropics. Data from the UK Peak District, an area where air pollution and intensive land management have triggered Sphagnum loss and peat erosion, suggest that additional anthropogenic pressures may trigger fluvial loss of much older (>500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.

  15. Distribution of uranium and thorium in sediments and plants from a granitic fluvial area

    International Nuclear Information System (INIS)

    Vargas, M.J.; Tome, F.V.; Sanchez, A.M.; Vazquez, M.T.C.; Murillo, J.L.G.

    1997-01-01

    A study of the presence of natural uranium and thorium isotopes in sediments and plants belonging to a granitic fluvial region of the Ortigas river (west of Spain) has been carried out. The existence of two uranium mines in the neighbourhood of the sampled sites and the granitic characteristics of the zone produce significant concentrations of natural radionuclides. Temporal and spatial variations of uranium and thorium concentrations and the activity ratios 234 U/ 238 U, 228 Th/ 232 Th and Th/U were studied to better understand the mobilization mechanisms such as leaching and transport at play in the studied system. These determinations were made using alpha-particle spectrometry with silicon detectors. The measurements were also compared with the results previously found for waters of this fluvial area. Uranium in sediments showed variations due to changes in rainfall, but thorium content was nearly constant. Uranium and thorium concentrations in plants were lower after rainfall. Incorporation of uranium into the plants seemed to be mainly from water, whereas incorporation of thorium seemed to be from both sediments and water. (Author)

  16. Quantifying bleaching for zero-age fluvial sediment: A Bayesian approach

    International Nuclear Information System (INIS)

    Cunningham, Alastair C.; Evans, Mary; Knight, Jasper

    2015-01-01

    Luminescence dating of sediment requires the sand grains to have been exposed to sunlight prior to their most recent burial. Under fluvial transport, the amount of sunlight exposure may not always be sufficient to reset the luminescence signal, a phenomenon known as ‘partial bleaching'. The extent of bleaching is dependent on a combination of geomorphic, sedimentological and fluvial processes. If bleaching can be quantified, and the relationship with these processes understood, it could potentially be used as a new environmental proxy for changes in the dynamics of river systems. Here, we use a recently developed statistical model to evaluate the extent of bleaching, by inferring the proportion of well-bleached grains in the small-aliquot population. We sampled low-flow and flood deposits at a single site on the River Sabie, South Africa. We show that the low-flow sediment is almost perfectly bleached (>80% of grains well bleached), while sediment at flood elevations is partially bleached (20–70 % of grains well bleached). The degree of bleaching may show a relationship with flood magnitude as defined by elevation above normal river level, and we speculate on the causes of variability in bleaching between flood samples. - Highlights: • We sampled modern river sediment from low-flow and flood elevations. • The unbleached OSL dose was measured. • Bayesian methods can estimate the proportion of well-bleached grains. • Low-flow sediments are well bleached; flood deposits are poorly bleached.

  17. Sediment Transport Dynamic in a Meandering Fluvial System: Case Study of Chini River

    Science.gov (United States)

    Nazir, M. H. M.; Awang, S.; Shaaban, A. J.; Yahaya, N. K. E. M.; Jusoh, A. M.; Arumugam, M. A. R. M. A.; Ghani, A. A.

    2016-07-01

    Sedimentation in river reduces the flood carrying capacity which lead to the increasing of inundation area in the river basin. Basic sediment transport can predict the fluvial processes in natural rivers and stream through modeling approaches. However, the sediment transport dynamic in a small meandering and low-lying fluvial system is considered scarce in Malaysia. The aim of this study was to analyze the current riverbed erosion and sedimentation scenarios along the Chini River, Pekan, Pahang. The present study revealed that silt and clay has potentially been eroded several parts of the river. Sinuosity index (1.98) indicates that Chini River is very unstable and continuous erosion process in waterways has increase the riverbank instability due to the meandering factors. The riverbed erosional and depositional process in the Chini River is a sluggish process since the lake reduces the flow velocity and causes the deposited particles into the silt and clay soil at the bed of the lake. Besides, the bed layer of the lake comprised of cohesive silt and clayey composition that tend to attach the larger grain size of sediment. The present study estimated the total sediment accumulated along the Chini River is 1.72 ton. The HEC-RAS was employed in the simulations and in general the model performed well, once all parameters were set within their effective ranges.

  18. Extreme Changes in Stream Geomorphic Conditions induced by Fluvial Scour in Bridges

    Science.gov (United States)

    Özcan, O.; Ozcan, O.

    2016-12-01

    The numerous complexities associated with bridge scour have caused scour to be one of the most active topics of stream geomorphic research. The assessment of local scouring mechanism around bridge piers provides information for decision-making regarding the pile footing design, predicting the safety of bridges under critical scoured conditions, and as a result, may help prevent unnecessary loses. In the study, bridge design plans and HEC-RAS modeling were used for the assessment of changes in stream geomorphic conditions. The derived fluvial scour depths were compared with the field measurements and the empirical formula which is based on stream flow discharge rate, streambed condition and shape of river. Preliminary results revealed that bridge damage resulting from the flood event in 2003 induced substantial scour around bridge piles. Afterwards, significant stream bed change was observed under the influence of fluvial scour in another flood occurred in 2009. Consequently, geomorphic conditions of the stream bed should be considered in the structural design of the bridges.

  19. Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.

    Science.gov (United States)

    Egger, Gregory; Politti, Emilio; Lautsch, Erwin; Benjankar, Rohan; Gill, Karen M; Rood, Stewart B

    2015-09-15

    River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. An inventory of published and unpublished fluvial-sediment data for California, 1956-70

    Science.gov (United States)

    Porterfield, George

    1972-01-01

    This inventory was prepared to provide a convenient reference to published and unpublished fluvial-sediment data for water years 1956-70, and updates substantially previous inventories. Sediment stations are listed in downstream order, and an alphabetical list of stations is also included. Figure 1 shows the approximate location of sediment stations in California. Most of the fluvial-sediment data in California were collected by the U.S. Geological Survey, under cooperative agreements with the following Federal, State, and local agencies: California Department of Water Resources, California Department of Navigation and Ocean Development, California Department of Fish and Game, Bolinas Harbor District, Monterey County Flood Control and Water Conservation District, Orange County Flood Control District, Riverside County Flood Control and Water Conservation District, San Diego County Department of Sanitation and Flood Control, San Luis Obispo County, San Mateo County, Santa Clara County Flood Control and Water District, Santa Cruz County Flood Control and Water Conservation District, Santa Cruz, city of, University of California, Ventura County Flood Control District, Forest Service, U.S. Department of Agriculture, Soil Conservation Service, U.S. Department of Agriculture, Corps of Engineers, U.S. Army, Bureau of Reclamation, U.S. Department of the Interior, National Park Service, U.S. Department of the Interior. This report was prepared by the Geological Survey under the general supervision of R. Stanley Lord, district chief in charge of water-resources investigations in California.

  1. Evolution of tertiary intermontane fluvial system of Powder River Basin, Wyoming and Montana

    International Nuclear Information System (INIS)

    Flores, R.M.; Ethridge, F.G.

    1985-01-01

    Exploration and development of economic coal and uranium deposits of the Tertiary Fort Union and Wasatch Formations provided data related to the evolution of depositional systems in the Powder River Basin. In ascending order, the Paleocene Fort Union Formation consists of the Tullock, Lebo, and Tongue River Members. The overlying Eocene Wasatch Formation consists of the conglomeratic Kingsbury and Moncrief Members and laterally equivalent finer grained deposits. Evolution of fluvial deposition in the basin was determined from sandstone percent maps. A high proportion of sandstones in the Tullock Member and combined Tongue River Member and Wasatch Formation formed in interconnected east-west and north-south belts. The east-west belts represent alluvial fans, as well as braided and meandering tributary streams. The north-south belts reflect meandering and anastomosing trunk streams fed by basin margin tributaries. The sandstones of the Lebo Shale show east-west trends and represent deposits of fluvio-deltaic systems that filled a western, closed-lacustrine basin. The lake in this basin may have formed during localized subsidence along the Buffalo deep fault. These contrasting styles of fluvial deposition were largely controlled by extrabasinal and intrabasinal tectonics associated with Laramide orogeny

  2. Impact of phenomenological theory of turbulence on pragmatic approach to fluvial hydraulics

    Science.gov (United States)

    Ali, Sk Zeeshan; Dey, Subhasish

    2018-04-01

    The phenomenological theory of turbulence (PTT) remains a long-standing and fascinating theory in turbulence research. In this review article, we highlight the state-of-the-science of the impact of the PTT on the pragmatic approach to fluvial hydraulics, explored over recent decades, discussing the salient and the subtle roles that the turbulence plays in governing many physical processes. To acquire a theoretical explanation of this pragmatic approach necessitates an intuitive thought that can bring together the background mechanisms of all the physical processes under one law—a thought that is capable of finding their inextricable links with the turbulent energy spectrum. We begin here with emphasizing the spectral and the co-spectral origin of the well-recognized laws of the wall, the resistance equation, and the turbulence intensities by portraying the typical momentum transfer mechanism of eddies in a turbulent flow. Next, we focus on the scaling laws of key fluvial processes derived from the perspective of the PTT, enlightening their physical insight and ability to judge how far the so-called empirical formulas can be used with confidence. The PTT has been able to disclose the origin of several primeval empirical formulas that have been used over many years without having any theoretical clarification and confirmation. Finally, we make an effort to describe some unsolved issues to be resolved as a future scope of research.

  3. Evidence of population resistance to extreme low flows in a fluvial-dependent fish species

    Science.gov (United States)

    Katz, Rachel A.; Freeman, Mary C.

    2015-01-01

    Extreme low streamflows are natural disturbances to aquatic populations. Species in naturally intermittent streams display adaptations that enhance persistence during extreme events; however, the fate of populations in perennial streams during unprecedented low-flow periods is not well-understood. Biota requiring swift-flowing habitats may be especially vulnerable to flow reductions. We estimated the abundance and local survival of a native fluvial-dependent fish species (Etheostoma inscriptum) across 5 years encompassing historic low flows in a sixth-order southeastern USA perennial river. Based on capturemark-recapture data, the study shoal may have acted as a refuge during severe drought, with increased young-of-the-year (YOY) recruitment and occasionally high adult immigration. Contrary to expectations, summer and autumn survival rates (30 days) were not strongly depressed during low-flow periods, despite 25%-80% reductions in monthly discharge. Instead, YOY survival increased with lower minimum discharge and in response to small rain events that increased low-flow variability. Age-1+ fish showed the opposite pattern, with survival decreasing in response to increasing low-flow variability. Results from this population dynamics study of a small fish in a perennial river suggest that fluvial-dependent species can be resistant to extreme flow reductions through enhanced YOY recruitment and high survival

  4. Excision of thymine dimers from specifically incised DNA by extracts of xeroderma pigmentosum cells

    Energy Technology Data Exchange (ETDEWEB)

    Cook, K; Friedberg, E C; Slor, H; Cleaver, J E

    1975-07-17

    DNA repair defects as exhibited in fibroblasts from patients with xeroderma pigmentosa were studied. Five complementation groups for excision-repair defects were examined to test the hypothesis that a defective endonuclease or exonuclease may be the cause. No evidence was found to indicate that the enzyme activity functions in dimer excision. Since ultraviolet irradiated E. coli DNA incised with an endonuclease purified from phage-infected cells were used, it is possible that other factors may be involved in human UV endonuclease action. (JWP)

  5. En bloc resection of huge cemento-ossifying fibroma of mandible: avoiding lower lip split incision.

    Science.gov (United States)

    Ayub, Tahera; Katpar, Shahjahan; Shafique, Salman; Mirza, Talat

    2011-05-01

    Cemento-ossifying Fibroma (COF) is an osteogenic benign neoplasm affecting the jaws and other craniofacial bones. It commonly presents as a progressively slow growing pathology, which can sometimes attain an enormous size, causing facial deformity. A case of a huge cemento-ossifying fibroma, appearing as a mandibular dumbell tumour in a male patient is documented, which caused massive bone destruction and deformity. It was surgically removed by performing en bloc resection of mandible avoiding the splitting of lower lip incision technique, thereby maintaining his normal facial appearance.

  6. Quantifying incision rates since the early Miocene: novelties, potentialities and limitations

    Science.gov (United States)

    Sartégou, A.; Braucher, R.; Blard, P. H.; Bourlès, D. L.; Zimmermann, L.; Tibari, B.; Voinchet, P.; Bahain, J. J.; Sorriaux, P.; Leanni, L.; Team, A.

    2017-12-01

    The rates and chronologies of valley incision are closely modulated by the tectonic uplift of active mountain ranges and were controlled by repeated climate changes during the Quaternary. The Pyrenees are a continental collision between the Iberian and Eurasian plates induced a double vergence orogen, which has been considered as a mature mountain range in spite of significant seismicity and evidence of neotectonics. Nevertheless, recent studies indicate that the range may have never reached a steady state. One option for resolving this controversy is to quantify the incision rates since the Miocene by reconstructing the vertical movement of geometric markers. However, the few available ages from the Pyrenean terrace systems do not exceed the middle Pleistocene. To enlarge the time span of this dataset, we studied alluvium-filled horizontal epiphreatic passages in limestone karstic networks, which represent former valley floors. They record the transient position of former local base levels during the process of valley deepening. We used various suitable geochronological methods (26Al/10Be, 10Be/21Ne, ESR and OSL burial durations on quartz) on intrakarstic alluvial deposits from three valleys of the central and eastern Pyrenees, as well as on a recent analogue. In the Pyrenean context, under particular conditions, these geochronometers allow us to document incision processes since 16-13 Ma, and to study influences of external forcing and eustatism. In comparison with other studies, it appears that incision rates are higher in the central Pyrenees and for the Spanish slope. However, the density of horizontal levels on an altimetric range, the geodynamical and paleoclimatic contexts, the reorganization of the drainage networks can make the filling stories of the networks more complex than expected. Indeed, these radiometric approaches may be limited when some formations are reworked inside and/or outside the karst. The validity of dosimetric methods in a mountainous

  7. Meta-analysis of negative-pressure wound therapy for closed surgical incisions

    DEFF Research Database (Denmark)

    Hyldig, N; Birke-Sorensen, H; Kruse, M

    2016-01-01

    . RESULTS: Ten studies met the inclusion criteria, reporting on 1311 incisions in 1089 patients. NPWT was associated with a significant reduction in wound infection (relative risk (RR) 0·54, 95 per cent c.i. 0·33 to 0·89) and seroma formation (RR 0·48, 0·27 to 0·84) compared with standard care....... The reduction in wound dehiscence was not significant. The numbers needed to treat were three (seroma), 17 (dehiscence) and 25 (infection). Methodological heterogeneity across studies led to downgrading of the quality of evidence to moderate for infection and seroma, and low for dehiscence. CONCLUSION: Compared...

  8. Anatomic study on mental canal and incisive nerve canal in interforaminal region in Chinese population.

    Science.gov (United States)

    Xu, Yun; Suo, Ning; Tian, Xiufen; Li, Fei; Zhong, Guangxin; Liu, Xiaoran; Bao, Yongxing; Song, Tao; Tian, Hua

    2015-08-01

    This study was aimed to detect the positions of mental canal and incisive nerve canal as well as the prolongation of mandibular canal in interforaminal region in Chinese population to supply the reference data of the surgical safe zone in chin for clinicians. A total of 80 formalin-fixed semi-mandibles of Chinese adult cadavers were dissected, the positions and courses of mental canal and incisive nerve canal as well as the prolongation of mandibular canal in interforaminal region were measured. The mental foramina were present in all cases (100 %), and most of them were located below 2nd premolar (58.75 %). Accessory mental foramina were observed in 5 %. The anterior end of mandibular canal, extending along the course of 7.37 ± 1.10 mm above the lower border of mandible to interforaminal region about 3.54 ± 0.70 mm medial to the mental foramen, most often ended below between the two premolars (73.75 %), where it continued as the incisive nerve canal (100 %) and the mental canal (96.25 %). Mental canal, with the wall formed by compact bone, being 2.60 ± 0.60 mm in diameter and 4.01 ± 1.20 mm in length, opened into mental foramen. Incisive nerve canal, with the wall formed by thin compact bone and/or partly or completely by spongy bone, being 1.76 ± 0.27 mm in diameter and 24.87 ± 2.23 mm in length, extended to the incisor region along the course of 9.53 ± 1.43 mm above the lower border of mandible, and most often ended below the lateral incisor (70.00 %). This research recommended for chin operations in Chinese population: the surgical safe zone could be set in the region about over 4 mm anterior to the mental foramen, and over 12 mm above inferior border of mandible for anterior alveolar surgery, or within 9 mm above inferior border of mandible for genioplasty.

  9. Wound healing in porcine skin following low-output carbon dioxide laser irradiation of the incision

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.K.; Garden, J.M.; Taute, P.M.; Leibovich, S.J.; Lautenschlager, E.P.; Hartz, R.S.

    1987-06-01

    Wound healing of scalpel incisions to the depth of adipose tissue closed with conventional methods was compared with closure by low-output carbon dioxide laser irradiation. In 3 Pitman-Moore minipigs wound healing was evaluated at intervals from 1 to 90 days by the following methods: clinical variables of wound healing; formation of the basement membrane components bullous pemphigoid antigen, laminin, and fibronectin; and histological evaluation of the regeneration of the epidermis, neovascularization, and elastin and collagen formation. There was no significant difference in healing between wounds closed by the various conventional methods and by the low-output carbon dioxide laser.

  10. Postcataract endophthalmitis prophylaxis using irrigation, incision hydration, and eye pressurization with vancomycin

    Directory of Open Access Journals (Sweden)

    Schelonka LP

    2015-07-01

    Full Text Available Lee P Schelonka,1 Margaret A SaBell2 1Department of Opthalmology, Kaiser Permanente Lone Tree Medical Offices, Lone Tree, 2Department of Infection Control, Kaiser Permanente Lone Tree Medical Offices, Lone Tree, Denver, CO, USA Purpose: This study aimed to determine whether switching from balanced salt solution (BSS to vancomycin 20 g/mL BSS for incision hydration and eye pressurization reduces the rate of postcataract endophthalmitis.Methods: This was a patient safety/quality improvement project, including all patients undergoing cataract surgery at the Kaiser Permanente Colorado Ophthalmology Department from January 2002 to December 2014. Throughout the study, patients received vancomycin 20 µg/mL in the irrigating solution. During the baseline period from 2002 to 2005, surgeons pressurized eyes and hydrated incisions with plain BSS. During the intervention period from 2006 through 2014, surgeons switched from BSS to the vancomycin/BSS irrigating solution for eye pressurization and incision hydration.Results: A total of 57,263 cataract operations were performed by 24 surgeons at seven surgical centers: 12,400 in the baseline period and 44,863 in the intervention period. The rate of postcataract endophthalmitis declined significantly from 5/12,400 (rate: 0.4/1,000 in the baseline period to 1/44,863 (rate: 0.022/1,000 during the intervention period (odds ratio [OR]: 18.1, 95% confidence interval [CI]: 2.11–154.9; χ2=13.5, P=0.00024. Accounting for an estimated 2.05-fold risk reduction due to confounding variables, the risk reduction attributed to the intervention remained significant: (adjusted OR: 8.78, 95% CI: 1.73–44.5; χ2=10.06, P=0.0015. Since 2009, we have not experienced any cases of postcataract endophthalmitis after 32,753 operations.Conclusion: We experienced a significant reduction in postcataract endophthalmitis when we switched from BSS to the vancomycin/BSS irrigating solution for incision hydration and eye pressurization

  11. Intra-parotid dermoid cyst: excision through a face lift incision.

    Science.gov (United States)

    Shakeel, M; Keh, S M; Chapman, A; Hussain, A

    2014-11-01

    Intra-parotid dermoid cysts are extremely rare. Clinically, they present like any other parotid lump and pre-operative diagnosis is rarely possible. A 62 years old Caucasian man presented with a painless lump in his right parotid region. The Mag