Sample records for rapid fluvial incision

  1. Rock slope response to fluvial incision in the central Swiss Alps (United States)

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


    The longitudinal profile of rivers intersecting the Rhone Valley in the central Swiss Alps suggests the development of topography throughout much of this region has been dominated by interglacial fluvial incision and ongoing tectonic uplift with only minimal glacial erosion since the mid-Pleistocene transition. Evidence indicates bedrock river incision during this period reflects a base level fall of between 500 m and 800 m (depending on the degree of overdeepening following an early period of enhanced glacial incision). This observation raises important questions regarding the preservation, or development of hillslope morphologies through multiple glacial-interglacial cycles. Since the pioneering works of Richter (1900) and Penck and Brückner (1909), Alpine geomorphologists have commented on a sequence of between three and five moderately dipping matched terraces that converge toward inferred paleo-river channels up to 800 m above the axis of many valleys. Here, we use a combination of integral analysis, forward streampower models, and a new method of topographic analysis based on high resolution LiDAR DEMs in order to test the correspondence of valley morphologies in this formerly glaciated landscape, with hillslope processes initiated by fluvial incision up to 700,000 years ago. Results indicate topography adjacent to reaches subjected to transient fluvial incision is characterized by a coherent region of consistently steep slopes, while narrow gorges correspond to rapid incision close to the Rhone valley since MIS 5. A majority of hillslopes converge to our initial fluvial valley floor, or the location of propagating knickpoints. The correspondence between intermediate-level terraces and modeled stages of river incision is, however, currently unclear. These results offer a unique insight into the long-term response of bedrock slopes to varying rates of base level fall, and the cumulative impact of glacial erosion on Alpine valley walls since MIS 11. Penck, A

  2. Climate-sensitive feedbacks between hillslope processes and fluvial erosion in sediment-driven incision models (United States)

    Skov, Daniel S.; Egholm, David L.


    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

  3. Late Quaternary fluvial incision rates in a marine terraced landscape, southeastern Crete, Greece (United States)

    Karymbalis, Efthimios; Papanastassiou, Dimitris; Valkanou, Kanella; Gaki-Papanastassiou, Kalliopi


    Along the southern coast of the island of Crete, a series of five east-west oriented Late Pleistocene marine terraces exist, demonstrating the significant coastal uplift of this area. These terraces, ranging in elevation from 10 to 160m, are deformed by the vertical movements of the NNE-SSW trending and dipping west normal fault of Ierapetra. This study focuses on defining rates of fluvial incision for the last 410 Ka along valley systems that drain the tectonically uplifting area of Ierapetra, south Crete. The studied streams have a N-S flow direction and discharge into the Libyan Sea. Some of them are developed on the uplifted block of the Ierapetra normal fault whereas others drain the subsiding area west of the fault. The lower reaches of the study streams cut down through these marine terraces, which have been recognized, mapped in detail and correlated with Late Pleistocene Oxygen-Isotope Stages of high sea-level stands following the global sea-level fluctuations. These terraces of known age were used as reference surfaces in order to determine fluvial incision rates as the lower reaches of the streams cut down through these platforms. To evaluate incision rates, thirty five topographic valley cross-sections were drawn through fieldwork measurements as well as using a digital elevation model (DEM) produced by detailed topographic diagrams at the scale of 1:5,000. Cross valley profiles were constructed at specific locations where streams cut down the inner edges of the marine terraces because these points correspond precisely to the age of the palaeo-shoreline during the interglacial stage. For each cross-section the ratio of valley floor width to valley height (Vf) and long-term mean stream incision rates were estimated for the last 410 Ka. The geomorphic evolution of the valleys has been mainly affected by the lithology of the bedrock, sea level fluctuations during the late Quaternary, the head-ward erosion and incision of the channels, as well as both the

  4. Timing of European fluvial terrace formation and incision rates constrained by cosmogenic nuclide dating (United States)

    Schaller, Mirjam; Ehlers, Todd A.; Stor, Tomas; Torrent, Jose; Lobato, Leonardo; Christl, Marcus; Vockenhuber, Christof


    Age constraints of late Cenozoic fluvial terraces are important for addressing surface process questions related to the incision rates of rivers, or tectonic and climate controls on denudation and sedimentation. Unfortunately, absolute age constraints of fluvial terraces are not always possible, and many previous studies have often dated terraces with relative age constraints that do not allow for robust interpretations of incision rates and timing of terrace formation. However, in situ-produced cosmogenic nuclides allow absolute age determination, and hence incision rates, of fluvial deposits back to 5 Ma. Here we present, cosmogenic depth profile dating and isochron burial dating of four different river systems in Europe spanning 12° of latitude. We do this to determine river incision rates and spatial variations in the timing of terrace formation. Isochron burial age constraints of four selected terraces from the Vltava river (Czech Republic) range between 1.00 ± 0.21 to 1.99 ± 0.45Ma. An isochron burial age derived for the Allier river (Central France) is 2.00 ± 0.17Ma. Five terrace levels from the Esla river (NW Spain) were dated between 0.08 + 0.04 / - 0.01Ma and 0.59 + 0.13 / - 0.20Ma with depth profile dating. The latter age agrees with an isochron burial age of 0.52 ± 0.20Ma. Two terrace levels from the Guadalquivir river (SW Spain) were dated by depth profile dating to 0.09 + 0.03 / - 0.02Ma and 0.09 + 0.04 / - 0.03Ma. The one terrace level from the Guadalquivir river dated by isochron burial dating resulted in an age of 1.79 ± 0.18Ma. Results indicate that the cosmogenic nuclide-based ages are generally older than ages derived from previous relative age constraints leading to a factor 2-3 lower incision rates than previous work. Furthermore, the timing of terrace formation over this latitudinal range is somewhat obscured by uncertainties associated with dating older terraces and not clearly synchronous with global climate variations.

  5. OSL dating of fluvial terraces for incision rate estimation and indication of neotectonic activity in Pamir (United States)

    Fuchs, M. C.; Gloaguen, R.; Krbetschek, M.; Szulc, A.


    ThePamir owes its special attraction for geo-scientists to being among Earth's largest intra-continental orogens and to display some of the highest uplift rates as well as to host among the most powerful river systems on the planet. The evolution of the drainage network as a proxy for the landscape's response to tectonic signals provides a powerful tool to study neotectonics. The relation between tectonic forcing and surface response is indicated by structural anomalies (e.g. river-capture, river-reversal or -deflection) and spatial differences of process rates (e.g. incision rates). We combine OSL dating with remote sensing tectonic geomorphology in order to determine the zones of active deformation in the Quaternary. The local drainage system of the study region aligns mainly to the east-west-trending belts of shortening, which results from the ongoing northward propagation of the Indian plate. In contrast the major trunk river, the Panj, is unusual in that it deflects northwards and then doubles back to the southwest, cutting the southern and central Pamir doming and several other major Cenozoic deformation zones. We use fluvial terraces along the deflected north-south orientated part including the doubled back prolongation of the more or less normal orientated Panj. These sediment bodies are used as a geomorphic record to reveal changes in the balance between sediment flux and discharge. Dating these fluvial terraces by OSL provides the burial ages of the sediments indicating periods of sedimentation. The remains of those periods are far from equally distributed and mark the time of local conditions for sedimentation as especially the close neighbourhood of most of the terraces from the two youngest periods demonstrate. Precise measurements of the heights of the dated terraces with respect to the present river level based on relative kinematic GPS quantify the total vertical incision of the river subsequent to the sedimentation and abandonment. Incision rates

  6. Experimental investigation of fluvial incision on Titan by low-velocity sediment impacts (United States)

    Polito, P. J.; Zygielbaum, B. R.; Sklar, L. S.; Collins, G.


    Images returned by the Cassini-Huygens mission reveal evidence for widespread fluvial incision in the polar regions of Titan. Dendritic channel networks draining to large lakes and the absence of cratering suggest active incision into Titan's water-ice bedrock surface. Previous work using the saltation-abrasion bedrock incision model suggests that a terrestrial channel transposed to Titan conditions would incise at remarkably similar rates, because the effects of Titan's lower gravity and less-dense sediments are offset by a much lower resistance to abrasion for ice than rock of similar strength. Here we report new laboratory measurements of ice erosion by low-velocity sediment impacts, part of a larger study investigating the temperature dependence of the material properties that control ice erodibility. We measure the energy required to erode a unit volume of ice using drop tests, in which a 110-150 g ice clast falls 5-10 cm onto a 20 cm diameter ice disk, and differences in mass and measurements of ice density are used to calculate the volume eroded. We construct the 10cm thick ice disks using 2-4 mm seed crystals and near-freezing distilled water. After freezing at 253 K a disk is placed in the bottom of a steel cylinder surrounded by dry ice and liquid nitrogen is pumped into the cylinder from below, chilling the ice to near-Titan temperatures for several hours but never submerging the samples (all drop test trials are completed in air). Our preliminary drop test results show that 4 J and 25 J are required to erode 1 cm3 of ice at temperatures of 205 K and110 K respectively, suggesting that ice may be no more than 2-3 times more erodible than previously-tested rocks of similar tensile strengths. A key limitation of this experimental method is the small size of our target disks, which fail catastrophically by through-cracking after several hundred drops. To avoid through-cracking and obtain direct measurements of ice surface erosion, we are preparing new

  7. Lake overspill and onset of fluvial incision in the Iranian Plateau: Insights from the Mianeh Basin (United States)

    Heidarzadeh, Ghasem; Ballato, Paolo; Hassanzadeh, Jamshid; Ghassemi, Mohammad R.; Strecker, Manfred R.


    Orogenic plateaus represent a prime example of the interplay between surface processes, climate, and tectonics. This kind of an interplay is thought to be responsible for the formation, preservation, and, ultimately, the destruction of a typical elevated, low-internal relief plateau landscape. Here, we document the timing of intermontane basin filling associated with the formation of a low-relief plateau morphology, followed by basin opening and plateau-flank incision in the northwestern Iranian Plateau of the Arabia-Eurasia collision zone. Our new U-Pb zircon ages from intercalated volcanic ashes in exposed plateau basin-fill sediments from the most external plateau basin (Mianeh Basin) document that the basin was internally drained at least between ∼7 and 4 Ma, and that from ∼5 to 4 Ma it was characterized by an ∼2-km-high and ∼0.5-km-deep lake (Mianeh paleolake), most likely as a result of wetter climatic conditions. At the same time, the eastern margin of the Mianeh Basin (and, therefore, of the Iranian Plateau) experienced limited tectonic activity, as documented by onlapping sediments and smoothed topography. The combination of high lake level and subdued topography at the plateau margin led to lake overspill, which resulted in the cutting of an ∼1-km-deep bedrock gorge (Amardos) by the Qezel-Owzan River (QOR) beginning at ∼4 Ma. This was associated with the incision of the plateau landscape and the establishment of fluvial connectivity with the Caspian Sea. Overall, our study emphasizes the interplay between surface and tectonic processes in forming, maintaining, and destroying orogenic plateau morphology, the transitional nature of orogenic plateau landscapes on timescales of 106 yr, and, finally, the role played by overspilling in integrating endorheic basins.

  8. A case of rapid rock riverbed incision in a coseismic uplift reach and its implications (United States)

    Huang, Ming-Wan; Pan, Yii-Wen; Liao, Jyh-Jong


    During the 1999 Chi-Chi earthquake (Mw = 7.6) in Taiwan, the coseismic displacement induced fault scarps and a pop-up structure in the Taan River. The fault scarps across the river experienced maximum vertical slip of 10 m, which disturbed the dynamic equilibrium of the fluvial system. As a result, rapid incision in the weak bedrock, with a maximum depth of 20 m, was activated within a decade after its armor layer was removed. This case provides an excellent opportunity for closely tracking and recording the progressive evolution of river morphology that is subjected to coseismic uplift. Based on multistaged orthophotographs and digital elevation model (DEM) data, the process of morphology evolution in the uplift reach was divided into four consecutive stages. Plucking is the dominant mechanism of bedrock erosion associated with channel incision and knickpoint migration. The astonishingly high rate of knickpoint retreat (KPR), as rapid as a few hundred meters per year, may be responsible for the rapid incision in the main channel. The reasons for the high rate of KPR are discussed in depth. The total length of the river affected by the coseismic uplift is 5 km: 1 km in the uplift reach and 4 km in the downstream reach. The downstream reach was affected by a reduction in sediment supply and increase in stream power. The KPR cut through the uplift reach within roughly a decade; further significant flooding in the future will mainly cause widening instead of deepening of the channel.

  9. The Influence of the Soil Water Balance Within Catchment Hillslopes on Runoff Variability and Fluvial Incision (United States)

    Rossi, M. W.; Whipple, K. X.; Vivoni, E. R.; DiBiase, R.; Heimsath, A. M.


    The variability of daily runoff has direct consequences on water availability, flood hazard, ecosystem function, and erosional processes. One component to predicting runoff variability is solid understanding of soil moisture dynamics and the runoff response to rainfall events. By using a point-scale soil water balance model that accounts for vegetation and soil properties, we test how daily rainfall statistics and vegetation response to water availability affect mean hydrologic partitioning and the runoff response during rare storms. Simulations span a transect in mean annual precipitation (MAP) from 200 to 1200 mm/year and are motivated by analysis of a long-term observational network of rainfall in the contiguous U.S. Whether driven by higher storm depths or increased frequency of storm arrivals, increases in MAP always lead to more fractional runoff generation due to the synchronous increase in mean antecedent soil moisture and probability of large rainfall events. Simulations also show that at any given MAP, there are important tradeoffs between increasing the probability of large rainfall events and associated decreases in the mean soil moisture state. Results from this ecohydrologic analysis are then used to drive 1-D simulations of the longitudinal river profile that account for runoff variability and thresholds to incision. We show that in natural settings where long-term hydrologic observations are available and where millennial-scale erosion rates were measured, much of the observed variation between local relief and long-term erosion rates can be explained by combining these two relatively simple models. However, we also show that large differences in MAP often lead to comparatively small differences in the geomorphically effective climate. This partially explains why prior studies have struggled to isolate a climatic control on long-term erosion rates. Expectations for how vegetation influences landscape evolution are often based on the seminal work by

  10. Spatial variations in fluvial incision across the eastern margin of Tibet reveal locus of deformation in the deep crust (United States)

    Kirby, Eric


    The manifestation of coupling among climate, erosion and tectonics along steep topographic margins of orogenic plateaus is strongly dependent on the processes driving crustal thickening. Along the eastern margin of the Tibetan Plateau, a long-standing and vigorous debate persists over whether mountain building occurred largely along upper-crustal faults or was the consequence of distributed thickening in the lower crust. Here I revisit this debate and show how surface deformation recorded by geomorphology over millennial timescales (10^4-105 yr) can yield insight into the role the deep crust along plateau margins. In contrast to the intensively studied Longmen Shan, the topographic margin of the Tibetan Plateau north of the Sichuan Basin follows the north-south Min Shan and cuts orthogonally across the structural grain of the Mesozoic West Qinling orogen. The lack of a direct association of topography with upper crustal faults affords an opportunity to evaluate the patterns of differential rock uplift from geomorphology. First, I employ an empirical calibration of river profile steepness (channel gradient normalized for drainage basin area) and erosion rate from cosmogenic 10Be concentrations in modern sediment. Application to the channels draining the plateau margin reveals a locus of high (300-500 m/Myr) erosion rate coincident with the Min Shan. Second, I present new results of surveying and dating of fluvial terraces developed along the Bailong Jiang, one of the major rivers draining across the plateau margin. A preliminary chronology of terrace formation and abandonment based on radiocarbon and OSL dating of fluvial deposits reveals systematic spatial gradients in fluvial incision, with highest incision rates (1000-2000 m/Myr) localized along the axis of the Min Shan and decreasing toward both the foreland and the plateau. This locus of incision has apparently been sustained through multiple generations of terrace formation and abandonment since at least 80 ka

  11. Spatial variations in fluvial incision across the eastern margin of Tibet reveal locus of thickening in the deep crust (United States)

    Kirby, Eric; Zhang, Huiping; Chen, Jie


    The manifestation of coupling among climate, erosion and tectonics along steep topographic margins of orogenic plateaus is strongly dependent on the processes driving crustal thickening. Along the eastern margin of the Tibetan Plateau, a long-standing an vigorous debate persists over whether mountain building occurred largely along upper-crustal faults or was the consequence of distributed thickening in the lower crust. Here we revisit this debate and show how surface deformation recorded by geomorphology over millennial timescales (104-105 yr) can yield insight into the role the deep crust along plateau margins. In contrast to the intensively studied Longmen Shan, the topographic margin of the Tibetan Plateau north of the Sichuan Basin follows the north-south Min Shan and cuts orthogonally across the structural grain of the Mesozoic West Qinling orogen. The lack of a direct association of topography with upper crustal faults affords an opportunity to evaluate the patterns of differential rock uplift from geomorphology. First, we employ an empirical calibration of river profile steepness (channel gradient normalized for drainage basin area) and erosion rate from cosmogenic 10Be concentrations in modern sediment. Application to the channels draining the plateau margin reveals a locus of high (300-500 m/Myr) erosion rate coincident with the Min Shan. Second, we present new results of surveying and dating of fluvial terraces developed along the Bailong Jiang, one of the major rivers draining across the plateau margin. A preliminary chronology of terrace tread deposits based on radiocarbon and OSL samples reveals systematic spatial gradients in fluvial incision, with highest incision rates (1000-2000 m/Myr) localized along the axis of the Min Shan and decreasing toward both the foreland and the plateau. This locus of incision has apparently been sustained through multiple generations of terrace formation and abandonment since ca. 80ka and thus is interpreted to reflect

  12. Transient fluvial incision and spatial distribution of active rock uplift in the Uspallata-Calingasta-Iglesia Valley, Central Argentina. (United States)

    Val, P.; Hoke, G. D.


    In the southern portion of the Pampean flat-slab subduction zone, a narrow, elongate intermontane depression separates the Precordillera fold-and-thrust belt from the Frontal and Principal Cordilleras of the high Andes. This depression, the Uspallata-Callingasta-Iglesia Valley, is divided into three catchments based on drainage divides between three large, transverse rivers. These catchments have their headwaters in the western Precordillera, Frontal Cordillera and Principal Cordillera ranges. Deformation is thought to have ceased near the core of the range (Frontal and Principal Cordilleras) and propagated to the east during the Miocene to present. In this study, river profiles and knickpoint topographic data are assessed to determine the distribution of active rock uplift and amount of fluvial incision in the Calingasta and Iglesia valleys. Slope-area data extracted from a digital elevation model consistently show slope-break knickpoints separating distinct sections of river profiles, which suggests relative bedrock uplift. Catchment-wide, normalized steepness indices (ksn) - using a concavity index of 0.45 (common in steady state profiles in the study area) - for both basins revealed consistently high ksn signals (>300) in the main stems and tributaries draining the Frontal Cordillera and the western Precordillera. The highest ksn values are situated in an elevation range of 2500 to 4000 m, west of the fold and thrust belt in the Principal and Frontal Cordilleras. Slope-break knickpoints are not clustered in elevation and there is no obvious correlation between upstream drainage area at knickpoints and respective distance from the tributaries' mouths, which suggests that they are not part of an upstream migrating wave of knickpoints. The data presented here indicate active rock uplift in the eastern edge of the Frontal Cordillera, which was previously considered inactive.

  13. Incision and uplift patterns along the Yellow River from fluvial terrace dating in northeastern Tibet: implications for plateau building (United States)

    van der Woerd, J.; Perrineau, A.; Gaudemer, Y.; Liu, J.; Pik, R.; Tapponnier, P.; Thuizat, R.; Zheng, R.


    Unraveling river development and tectonics allow constrain key processes of landscape evolution and continental plateau building. In northeastern Tibet, the Yellow River escapes from the plateau towards the northeast crossing 2 of the largest strike-slip faults of Tibet and no less than 5 NW-SE striking, actively growing ranges and intervening basins. Across the Kunlun and Haiyuan strike-slip faults the Yellow River course show large deflections of about 80-90 km and 50-100 km, respectively. Despite undetermined total geological offsets along the faults, these deflections are best interpreted as tectonic offsets of comparable amounts. In addition, cosmogenic isotope dating of Yellow River terraces abandoned on the eastern flank of the Mijia Shan push-up in a bend of the Haiyuan fault allow constrain an uplift-rate of about 1 mm/yr implying onset of deformation of the push-up about 1 Ma. Between the strike-slip faults and upstream of Lanzhou, Plio-Quaternary deposits and fluvial terraces testify to a previous phase of aggradation. In particular, the high and flat paleo-base levels (3200 m) of the Gonghe and Guide basins, together with that of the Qinghai lake basin imply the existence of a greater parent basin dammed by uplift of the Riyue Shan, prior to, or during the growth of the upper Yellow River catchment. Today, the river has cut a 500 km-long gorge, eroding much of the 1000 m-thick Quaternary sediment pile, and incising steep-walled canyons across the ranges. The corresponding base level drop has left a spectacular flight of seven major terrace levels across the 50 km-wide Gonghe basin, with additional strath terraces abrading the Waliguan bedrock. The main terraces slope to the northeast, sub-parallel to the Yellow River course. In contrast, the cobble-paved bedrock straths north and south of the EW-trending Longyang canyon slope westwards, opposite to the river gradient, attesting to recent tectonic uplift and tilting of the Waliguan range. Cosmogenic

  14. Fast fluvial incision in the Olympic Mountains, NW Washington State: Short-term geomorphic unsteadiness in a steady-state orogen (United States)

    Brown, E.; Gasparini, N. M.; Brandon, M. T.


    We use trunk and tributary profiles in the Olympic Mountains in northwestern Washington State to explore the idea of how well slope and area can be used to estimate long-term bedrock incision rates and rock uplift rates. Gasparini and Brandon (2011) show that all incision models have a common empirical power law form, where I={k'}Am'}S{n', and that the parameters are constant at a regional scale, and hold for both trunk and tributary channels. Long-term incision rates determined for the Clearwater drainage in the western Olympics by Pazzaglia and Brandon (2001) are used to estimate m'= 0.46 and n'= 0.98. Tomkin et al. (2003) found much smaller values for m', but that solution was biased by a small span of values in slope and area. We have found that including data from both trunk and tributary channels allows the regression to find more stable parameter estimates, especially for m'. The Clearwater calibration is then used to predict the incision rates for the rest of the region. To extract reliable values for the channel gradient, we use a lowess regression method, with a weighted bandwidth of about 300 m. Note that our analysis carries no assumptions about glaciation because the predicted incision rates are solely dependent on the current morphology of the landscape. We find that the predicted incision is fast in the center of the range, with rates up to 8 times greater than estimations for long-term erosion rates and rock uplift rates, but are otherwise similar to rates in the foothills. Our results demonstrate that it is possible for a steady-state orogen, like the Olympics, to experience geomorphic unsteadiness over short time scales. As a result, at any given time fluvial incision rates may vary widely from long-term erosion rates and rock uplift rates.

  15. Rapid incision of the Colorado River in Glen Canyon - insights from channel profiles, local incision rates, and modeling of lithologic controls (United States)

    Cook, K.L.; Whipple, K.X.; Heimsath, A.M.; Hanks, T.C.


    The Colorado River system in southern Utah and northern Arizona is continuing to adjust to the baselevel fall responsible for the carving of the Grand Canyon. Estimates of bedrock incision rates in this area vary widely, hinting at the transient state of the Colorado and its tributaries. In conjunction with these data, we use longitudinal profiles of the Colorado and tributaries between Marble Canyon and Cataract Canyon to investigate the incision history of the Colorado in this region. We find that almost all of the tributaries in this region steepen as they enter the Colorado River. The consistent presence of oversteepened reaches with similar elevation drops in the lower section of these channels, and their coincidence within a corridor of high local relief along the Colorado, suggest that the tributaries are steepening in response to an episode of increased incision rate on the mainstem. This analysis makes testable predictions about spatial variations in incision rates; these predictions are consistent with existing rate estimates and can be used to guide further studies. We also present cosmogenic nuclide data from the Henry Mountains of southern Utah. We measured in situ 10Be concentrations on four gravel-covered strath surfaces elevated from 1 m to 110 m above Trachyte Creek. The surfaces yield exposure ages that range from approximately 2??5 ka to 267 ka and suggest incision rates that vary between 350 and 600 m/my. These incision rates are similar to other rates determined within the high-relief corridor. Available data thus support the interpretation that tributaries of the Colorado River upstream of the Grand Canyon are responding to a recent pulse of rapid incision on the Colorado. Numerical modeling of detachment-limited bedrock incision suggests that this incision pulse is likely related to the upstream-dipping lithologic boundary at the northern edge of the Kaibab upwarp. ?? 2009 John Wiley & Sons, Ltd.

  16. Transient fluvial incision as an indicator of active faulting and surface uplift in the Moroccan High Atlas. (United States)

    Boulton, Sarah; Stokes, Martin; Mather, Anne


    Quantifying the extent to which geomorphic features can be used to extract tectonic signals is a key challenge for the Earth Sciences. Here, we analyse the long profiles of rivers that drain southwards across the Southern Atlas Fault (SAF), a segmented thrust fault that forms the southern margin of the High Atlas Mountains in Morocco, with the aim of deriving new data on the recent activity of this little known fault system. River long profiles were extracted for the 32 major rivers that drain southwards into the Ouarzazate foreland basin. Of these, twelve exhibit concave-up river profiles with a mean concavity (Θ) of 0.61 and normalized steepness indices (Ksn) in the range 42-219; these are interpreted as rivers at or near steady-state. By contrast, 20 rivers are characterised by the presence of at least one knickpoint upstream of the thrust front. Knickzone height (the vertical distance between the knickpoint and the fault) varies from 100 - 1300 m, with calculated amounts of uplift at the range bounding fault ranging from 1040 - 80 m. In map view, knickpoint locations generally plot along sub-parallel lines to the thrust front and there are no obvious relationships with specific lithological units or boundaries. Furthermore, drainage areas upstream of the knickpoints range over several orders of magnitude indicating that they are not pinned at threshold drainage areas. Therefore, these features are interpreted as a transient response to base-level change. However, three distinct populations of knickpoints can be recognised based upon knickpoint elevation, these are termed K1, K2 and K3 and channel reaches are universally steeper below knickpoints than above. K1 and K2 knickpoints share common characteristics in that the elevation of the knickpoints, calculated incision and ksn all increase from west to east. Whereas, K3 knickpoints show little systematic variation along the range front, are observed at the lowest altitudes with calculated incision of < 200 m

  17. Fine-scale characteristics of fluvial bull trout redds and adjacent sites in Rapid River, Idaho, 1993-2007 (United States)

    John W. Guzevich; Russell F. Thurow


    From 1993 to 2007, we used single pass, September surveys to locate and measure fluvial bull trout (Salvelinus confluentus) redds in Rapid River, Idaho. Here we describe substrate sizes, redd dimensions, and water depths, velocities, and temperatures within and adjacent to 337 redds. Most (79%) spawning sites had fewer than 20% surface fines (< 2 mm) and mean,...

  18. Climate and base-level controlled fluvial system change and incision during the last glacial–interglacial transition, Roer river, the Netherlands – western Germany

    NARCIS (Netherlands)

    Kasse, C.; Balen, Van R.T.; Bohncke, S.J.P.; Wallinga, J.; Vreugdenhil, M.


    The fluvial development of the Roer river in the southeastern Netherlands and western Germany is presented for the Late Pleniglacial, Late-glacial and Early Holocene periods. Reconstruction of fluvial-style changes is based on geomorphological and sedimentological analysis. Time control comes from c

  19. Fluvial response to the last Holocene rapid climate change in the Northwestern Mediterranean coastlands (United States)

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


    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.

  20. Rapid healing of gingival incisions by the helium-neon diode laser. (United States)

    Neiburger, E J


    Fifty-eight extraction patients had one of two gingival flap incisions lased with a 1.4 mw helium-neon (670 nm) diode laser for 30 seconds (fluence = 0.34 J/cm2). Healing rates were evaluated clinically and photographically. Sixty-nine percent of the irradiated incisions healed faster than the control incisions. No significant difference in healing was noted when patients were compared by age, gender, race, and anatomic location of the incision. This study concludes that helium-neon diode lasers, at the previously mentioned energy level, increase the rate of gingival wound healing in 69 percent of patients, without any side effects. For the last 30 years, low-power lasers in dentistry have appeared to stimulate healing rates and increase the rate of repair of injured tissue. Helium-neon and similar lasers emit light in the red (600-700 nm) spectrums and produce energy densities (fluences) below 20 Joules/cm2. They have been studied in a variety of animal tissue culture and human evaluations to determine their ability to increase the rates of wound healing by biostimulation. Over the last three decades, researchers have found that ruby and gas helium-neon (low-power laser radiation) have a biostimulatory effect on living tissue. Studies show that under specific conditions, red spectrum laser light speeds the healing of wounds. Photons from the red light lasers, which include ruby lasers (694 nm), helium-neon gas lasers (632 nm), and helium-neon diode lasers (650-670 nm), appear to stimulate rapid epithelialization and fibroblast (collagen) proliferation in animal and human tissue cultures. Low-power lasers have been reported to reduce post-extraction pain and swelling and to increase rates of wound healing (including scar formation, phagocytosis) in cell culture, animal, and human clinical studies. The new, compact, and inexpensive (under $50) helium-neon diode lasers have produced similar effects. These FDA Class IIIa lasers have no hazards associated with them

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

    Directory of Open Access Journals (Sweden)

    X. X. Lu


    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.

  2. Two-dimensional coupled mathematical modeling of fluvial processes with intense sediment transport and rapid bed evolution

    Institute of Scientific and Technical Information of China (English)

    YUE ZhiYuan; CAO ZhiXian; LI Xin; CHE Tao


    Alluvial rivers may experience intense sediment transport and rapid bed evolution under a high flow regime, for which traditional decoupled mathematical river mod-els based on simplified conservation equations are not applicable. A two-dimen-sional coupled mathematical model is presented, which is generally applicable to the fluvial processes with either intense or weak sediment transport. The governing equations of the model comprise the complete shallow water hydrodynamic equa-tions closed with Manning roughness for boundary resistance and empirical rela-tionships for sediment exchange with the erodible bed. The second-order Total-Variation-Diminishing version of the Weighted-Average-Flux method, along with the HLLC approximate Riemann Solver, is adapted to solve the governing equations, which can properly resolve shock waves and contact discontinuities. The model is applied to the pilot study of the flooding due to a sudden outburst of a real glacial-lake.

  3. Two-dimensional coupled mathematical modeling of fluvial processes with intense sediment transport and rapid bed evolution

    Institute of Scientific and Technical Information of China (English)


    Alluvial rivers may experience intense sediment transport and rapid bed evolution under a high flow regime,for which traditional decoupled mathematical river mod-els based on simplified conservation equations are not applicable. A two-dimen-sional coupled mathematical model is presented,which is generally applicable to the fluvial processes with either intense or weak sediment transport. The governing equations of the model comprise the complete shallow water hydrodynamic equa-tions closed with Manning roughness for boundary resistance and empirical rela-tionships for sediment exchange with the erodible bed. The second-order Total-Variation-Diminishing version of the Weighted-Average-Flux method,along with the HLLC approximate Riemann Solver,is adapted to solve the governing equations,which can properly resolve shock waves and contact discontinuities. The model is applied to the pilot study of the flooding due to a sudden outburst of a real glacial-lake.

  4. Linking hydrologic and bedload transport models to simulate fluvial response to changing precipitation (United States)

    Wickert, A. D.; Ng, G. H. C.; Tofelde, S.; Savi, S.; Schildgen, T. F.; Alonso, R. N.; Strecker, M. R.


    Changes in precipitation can drive river aggradation or incision through their influence on both hillslope processes, which supply sediment to the channel, and sediment transport capacity, which moves sediment downstream. Whether a particular change in precipitation intensity and/or duration will result in aggradation or incision is difficult to predict due to these competing effects. In particular, fluvial response to climate change is sensitive to (1) thresholds and nonlinearities involved in sediment production and sediment transport, (2) how different modes of sediment production affect the grain size of the sediment provided to the channel, and (3) impacts of drainage basin geometry on sediment storage time and locations of rapid sediment production and/or transport. A better mechanistic understanding of the relationship between rainfall and river bed elevation changes will help us to understand modern river channel response to climate change and decipher the causes for fluvial terrace formation. Here we couple a hydrologic model, the Precipitation-Runoff Modeling System (PRMS), with a model of sediment transport through a fluvial network, sedFlow, to predict patterns of bed elevation change. We first perform schematic example simulations on an idealized synthetic landscape with a single river channel to show how simple fluvial systems can respond to changes in rainfall. We then expand these numerical tests to full fluvial networks, in which the segments of the tributary network propagate signals of aggradation and incision, leading to a more complex response that embodies the interference between magnitudes and time-scales of sediment transfer in the tributary links. We showcase the possible complexity of the fluvial response with an example from the Quebrada del Toro of NW Argentina, which is currently experiencing rapid and spatially-variable aggradation and incision, possibly in response to an increase in extreme rainfall events in the east-central Andes.

  5. Estuarine fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution (United States)

    van der Schriek, Tim; Passmore, David G.; Rolão, Jose; Stevenson, Anthony C.


    We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial incision-deposition. We suggest that several incision-aggradation phases may have occurred during glacial periods. Major aggradation events may overlap with cold episodes, while incision appears to concentrate on the warming limb of climate transitions. The complex stratigraphy of the Quaternary record in the Lower Tagus valley is influenced by repeated base-level and climate changes. This paper submits the first chronostratigraphic framework for valley fill deposits in the Lower Tagus area. Sea-level rise forced aggradation and controlled deposition of the fine-grained sedimentary wedge underlying the low-gradient Lower Tagus floodplain. Investigations have focused on the lower Muge tributary, where rapidly aggrading estuarine and fluvial environments were abruptly established (∼8150 cal BP) as sea level rose. Base level at the valley mouth controlled the upstream extent of the fine-grained backfill. Tidal environments disappeared abruptly (∼5800 cal BP) when the open estuary at the Muge confluence was infilled by the Tagus River. The decrease and final still stand of sea-level rise led to floodplain stabilisation with peat (∼6400-5200 cal BP) and soil formation (∼5200-2200 cal BP). Localised renewed sedimentation (∼2200-200 cal BP) is linked to human activity.

  6. The Response of Fluvial Landscapes to Glaciation (United States)

    Brocklehurst, S. H.; Whipple, K. X.


    A major consequence of climate cooling is the growth of glaciers in mountain ranges previously sculpted by fluvial and hillslope processes. Climate change and the tectonics of mountain ranges are linked if glacial erosion either alters the relief structure, or exhumes material in a different fashion from rivers. Glacial erosion carves cirques and U-shaped valleys, and cooler climates also affect hillslope processes, as freeze-thaw, rockfall, landsliding and debris flows start to dominate. The signature of glacial erosion on the landscape is readily identified from digital elevation model (DEM) analyses, including hypsometry and longitudinal profiles, and comparison with the evolution of fluvial landscapes can be made using a landscape evolution model. These techniques demonstrate that the evolution of glaciated landscapes is not a simple function of regional climate change. In smaller drainage basins in the eastern Sierra Nevada, California, glaciers have generated modest relief, and have incised the valley floor at higher elevations. In larger drainage basins, where accumulation areas are greater and the rainshadow effect is less, glaciers have carved a strikingly different morphology. There is more relief, and valley floor incision occurs at much lower elevations. The Sangre de Cristo Range, Colorado, has evolved similarly, although with pronounced asymmetry, caused by the prevailing winds from the west. Accumulation of wind-blown snow on the eastern side of the range causes much more substantial erosion and deposition of spectacular moraines. In more tectonically active regions, such as the Southern Alps of New Zealand, and the Nanga Parbat region of Pakistan, smaller glacial valley floors steepen in response to rapid rock uplift, whereas larger glaciers maintain shallow gradients despite rapid rock uplift. Hillslope processes are apparently slower than valley floor incision, at least for some period, allowing dramatic relief production and decoupling of valley

  7. Fluvial Apophenia (United States)

    Coulthard, Tom; Armitage, John


    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.

  8. Protracted fluvial recovery from medieval earthquakes, Pokhara, Nepal (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


    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

  9. Hillslope-derived blocks retard river incision (United States)

    Shobe, Charles M.; Tucker, Gregory E.; Anderson, Robert S.


    The most common detachment-limited river incision models ignore the effects of sediment on fluvial erosion, yet steep reaches of mountain rivers often host clusters of large (>1 m) blocks. We argue that this distribution of blocks is a manifestation of an autogenic negative feedback in which fast vertical river incision steepens adjacent hillslopes, which deliver blocks to the channel. Blocks inhibit incision by shielding the bed and enhancing form drag. We explore this feedback with a 1-D channel-reach model in which block delivery by hillslopes depends on the river incision rate. Results indicate that incision-dependent block delivery can explain the block distribution in Boulder Creek, Colorado. The proposed negative feedback may significantly slow knickpoint retreat, channel adjustment, and landscape response compared to rates predicted by current theory. The influence of hillslope-derived blocks may complicate efforts to extract base level histories from river profiles.

  10. Tibetan plateau river incision inhibited by glacial stabilization of the Tsangpo gorge. (United States)

    Korup, Oliver; Montgomery, David R


    A considerable amount of research has focused on how and when the Tibetan plateau formed in the wake of tectonic convergence between India and Asia. Although far less enquiry has addressed the controls on river incision into the plateau itself, widely accepted theory predicts that steep fluvial knick points (river reaches with very steep gradients) in the eastern Himalayan syntaxis at the southeastern plateau margin should erode rapidly, driving a wave of incision back into the plateau. Preservation of the plateau edge thus presents something of a conundrum that may be resolved by invoking either differential rock uplift matching erosional decay, or other mechanisms for retarding bedrock river incision in this region where high stream power excludes the potential for aridity as a simple limit to dissection of the plateau. Here we report morphologic evidence showing that Quaternary depression of the regional equilibrium line altitude, where long-term glacier mass gain equals mass loss, was sufficient to repeatedly form moraine dams on major rivers: such damming substantially impeded river incision into the southeastern edge of the Tibetan plateau through the coupled effects of upstream impoundment and interglacial aggradation. Such glacial stabilization of the resulting highly focused river incision centred on the Tsangpo gorge could further contribute to initiating and accentuating a locus of rapid exhumation, known as tectonic anaeurysm.

  11. Multiple climatic cycles imprinted on regional uplift-controlled fluvial terraces in the lower Yalong River and Anning River, SE Tibetan Plateau (United States)

    He, Zexin; Zhang, Xujiao; Bao, Shuyan; Qiao, Yansong; Sheng, Yuying; Liu, Xiaotong; He, Xiangli; Yang, Xingchen; Zhao, Junxiang; Liu, Ru; Lu, Chunyu


    The development of fluvial systems on the southeastern margin of the Tibetan Plateau is linked to significant and rapid late Cenozoic uplift. The relatively complete fluvial terrace sequence preserved along the Yalong River valley and that of its tributary, the Anning River, provides an excellent archive for studying the development of terraces in rapidly uplifting mountainous areas. This study reveals that terrace development is predominantly controlled by multiscale climate cycles and long-term uplift, as shown by terrace dating, sedimentary characteristics, and incision rates. At least six alluvial terrace units were identified in 20 transverse sections through the terraces along about a 600 km length of river and were dated using Electron Spin Resonance (ESR) and Optically Stimulated Luminescence (OSL). The climatostratigraphic positions of the terrace deposits and their respective age constraints suggest that fluvial aggradation was concentrated during Marine Isotope Stages (MIS) 32, 22, 18, 4, 2, and the Younger Dryas (YD) and that incision occurred during the succeeding cold-to-warm transitions. The changes in fluvial style marked by terraces 6, 5, and 4 predominantly occurred in synchrony with the 100-ka Milankovitch climate cycles, while terraces 3 and 2 were controlled by the obliquity-driven 41-ka climate cycles. Finally, the aggradation of terrace T1 occurred in response to the YD stadial. During the intervening time between 0.72 and 0.063 Ma, terraces either did not form or were not preserved, which may suggest that uplift rates varied through time and influenced terrace formation/preservation. The progressive valley incision recorded by these fluvial terraces cannot be entirely explained by climate cycling alone. Temporal and spatial variations in incision rates indicate that the continuing long-term incision has been driven by uplift. The temporal distribution of the incision rates reveals two rapidly uplifting stages in the southeastern Tibetan

  12. Quantification of fluvial response to tectonic deformation in the Central Pontides, Turkey; inferences from OSL dating of fluvial terraces (United States)

    McClain, Kevin; Yıldırım, Cengiz; Çiner, Attila; Akif Sarıkaya, M.; Şahin, Sefa; Özcan, Orkan; Güneç Kıyak, Nafiye; Öztürk, Tuǧba


    From Late Miocene to present, Anatolia's rapid counterclockwise movement, which increases in velocity towards the Hellenic Arc, has formed the North Anatolian Fault (NAF), a dextral transform fault along the Anatolia-Eurasia plate boundary and the northern margin of the Central Anatolian Plateau (CAP). A zone of transpression referred to as the Central Pontides exists between the broad restraining bend of the NAF and the Black Sea Basin, uplifting what is interpreted as a detached flower structure. Dating of Quaternary landforms in the eastern flank of the Central Pontides has helped to understand its recent deformation. However, in the western flank of the Central Pontides there is an absence of Quaternary studies, relatively quiet modern seismicity, and difficulties locating or observing fault scarps. This led us to use optically stimulated luminescence dating (OSL-dating) of fluvial terrace sediments and the study of geomorphic features to gain insight into the influence of climate and tectonics on landscape evolution of this area. In this area, the Filyos River crosses the Karabük Fault (reverse fault) and deeply incises a gorge through the Karabük Range before flowing towards the Black Sea. In the gorge an abundance of indicators of tectonic deformation were mapped, such as hanging valleys, wind gaps, bedrock gorges, landslides, steep V-shaped channels, tilted basins, as well as fluvial strath terraces. In particular, strath terraces of at least 8 levels within just 1.5 km of horizontal distance were examined. We used OSL-dating to estimate five deposition ages of fluvial strath terrace sediments, leading to an estimation of incision and uplift rates over time. Using three samples per terrace with strath elevations of 246 ± 0.2 m, 105.49 ± 0.2 m, 43.6 ± 0.2 m, 15.3 ± 0.2 m and 3.6 ± 0.2 m above the Filyos River, we determined corresponding ages of 841 ± 76 ka, 681 ± 49 ka, 386 ± 18 ka, 88 ± 5.1 ka and 50.9 ± 2.8 ka. Incision rates over time (oldest

  13. Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision (United States)

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


    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.

  14. Landscape evolution due to river incision in active mountains (United States)

    Lavé, L.; Attal, A.


    It is commonly accepted that fluvial network incision control the local base level for hillslopes and therefore controls the rate of landscape denudation, and thus the way the landscape will respond to tectonic or climatic forcings. For that reason, many studies have focused for the last ten years in quantifying fluvial incision rates and the mechanisms of fluvial incision into bedrock. In many morphotectonic settings the shear stress model has been widely used and provided satisfactory first order description of the river incision in active mountains. Across the Siwaliks range in front of the Himalaya, the shear stress model (that also includes bedload mean pebble size and explicit channel width variations), provides a good proxy to estimate incision and uplift rate, that can be measured independently from fluvial terraces studies. By transposition and after calibration to more resistant crystalline lithologies, this model helped to define the incision rate profiles across the whole Himalayan ranges. These profiles were found coherent with current seismotectonic model, sediment budget, fluvial terrace studies and geochronology results. More importantly, the incision model was found to provide good results in two other active regions: across the Nanga Parbat massif in Pakistan, and in the San Gabriel Ranges in California, with only minor required changes of the erodibility coefficient despite very different hydroclimatic setting. However, this semi-empirical model is not mechanically satisfying: in many settings, river bedload fluxes exert an important control on incision rates, by limiting bedrock exposure or by providing an efficient tool for river mechanical abrasion. A reappraisal of the former examples as thus conducted in order to test different models including the role of sediment fluxes. General results and models will be first discussed in light of their physical consistency with field and experimental data on pebble and bedrock abrasion, and second in

  15. Fluvial archives, a valuable record of vertical crustal deformation (United States)

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


    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

  16. Channel incision and water quality (United States)

    Shields, F. D.


    Watershed development often triggers channel incision that leads to radical changes in channel morphology. Although morphologic evolution due to channel incision has been documented and modeled by others, ecological effects, particularly water quality effects, are less well understood. Furthermore, environmental regulatory frameworks for streams frequently focus on stream water quality and underemphasize hydrologic and geomorphic issues. Discharge, basic physical parameters, solids, nutrients (nitrogen and phosphorus), chlorophyll and bacteria were monitored for five years at two sites along a stream in a mixed cover watershed characterized by rapid incision of the entire channel network. Concurrent data were collected from two sites on a nearby stream draining a watershed of similar size and cultivation intensity, but without widespread incision. Data sets describing physical aquatic habitat and fish fauna of each stream were available from other studies. The second stream was impacted by watershed urbanization, but was not incised, so normal channel-floodplain interaction maintained a buffer zone of floodplain wetlands between the study reach and the urban development upstream. The incised stream had mean channel depth and width that were 1.8 and 3.5 times as large as for the nonincised stream, and was characterized by flashier hydrology. The median rise rate for the incised stream was 6.4 times as great as for the nonincised stream. Correlation analyses showed that hydrologic perturbations were associated with water quality degradation, and the incised stream had levels of turbidity and solids that were two to three times higher than the nonincised, urbanizing stream. Total phosphorus, total Kjeldahl N, and chlorophyll a concentrations were significantly higher in the incised stream, while nitrate was significantly greater in the nonincised, urbanizing stream (p Ecological engineering of stream corridors must focus at least as much energy on mediating hydrologic

  17. Simulation of channel sandstone architecture in an incised valley

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  18. Comparing OSL and CN techniques for dating fluvial terraces and estimating surface process rates in Pamir (United States)

    Fuchs, Margret; Gloaguen, Richard; Pohl, Eric; Sulaymonova, Vasila; Merchel, Silke; Rugel, Georg


    The quantification of surface process rates is crucial for understanding the topographic evolution of high mountains. Spatial and temporal variations in fluvial incision and basin-wide erosion enable to decipher the role of tectonic and climatic drivers. The Pamir is peculiar in both aspects because of its location at the western end of the India-Asia collision zone, and its position at the edge of two atmospheric circulation systems, the Westerlies and the Indian Summer Monsoon. The architecture of the Panj river network indicates prominent variations across the main tectonic structures of the Pamir. The trunk stream, deflects from the predominantly westward river orientation and cuts across the southern and central Pamir domes before doubling back to the west and leaving the orogen. Optically stimulated luminescence (OSL) dating of fluvial terraces reveals short-term sedimentation along the trunk stream during the last ~25 kyr. The agreement of OSL results to new exposure ages based on the cosmogenic nuclide (CN) 10Be confirms accurate terrace age modelling and treatment of incomplete bleaching. The consistent terrace sedimentation and exposure ages suggest also fast terrace abandonment and rapid onset of incision. Considerable differences in terrace heights reflect high spatial variations of fluvial incision, independent of time interval, change in rock type or catchment increase. Highest rates of (5.9 ± 1.1) mm/yr to (10.0 ± 2.0) mm/yr describe the fluvial dynamic across the Shakhdara Dome and that related to the Darvaz Fault Zone. Lower rates of (3.9 ± 0.6) mm/yr to (4.5 ± 0.7) mm/yr indicate a transient stage north of the Yazgulom Dome. Fluvial incision decreases to rates ranging from (1.7 ± 0.3) mm/yr to (3.9 ± 0.7) mm/yr in graded river reaches associated to southern dome boundaries. The pattern agrees to the interpretation of successive upstream river captures across the southern and central Pamir domes inferred from morphometric analyses of river

  19. Laser Scanning Applications in Fluvial Geomorphology (United States)

    Alho, P.


    During recent decades, the use of high-resolution laser scanning data in fluvial studies has rapidly increased. Airborne laser scanning (ALS) can be used to extensively map riverine topography. Laser scanning data have great potential to improve the effectiveness of topographical data acquisition and the accuracy and resolution of DTMs (Digital Terrain Models) needed in fluvial geomorphology. Airborne Laser Scanning (ALS) is applicable for mapping areas varying from reach to catchment scale and these data are, therefore, particularly suitable, especially for hydraulic modelling, mapping of flood inundation, and the detection of macro-scale fluvial geomorphology. With Terrestrial Laser Scanning (TLS) a spatial resolution of less than 1 mm and a range accuracy of few millimetres can be achieved. Mobile Laser Scanning (MLS) enables a remarkably faster survey approach compared to the conventional TLS method. One of the newest applications of MLS approaches involves a boat/cart/backpack -based mobile mapping system. This set-up includes laser scanning and imaging from a platform moving along a river course or floodplain and may be used to expand the spatial extent of terrestrial scanning. Detailed DTMs derived from laser scanning data can be used to improve the recognition of fluvial landforms, the geometric data of hydraulic modelling, and the estimation of flood inundation extents and the associated fluvial processes. Fluvial environments also offer challenges for the application of laser scanning techniques. Factors such as vegetation cover, terrain undulation, coarse surface materials and water surfaces may distort a laser scanning survey.

  20. A fluvial record of the mid-Holocene rapid climatic changes in the middle Rhone valley (Espeluche-Lalo, France) and of their impact on Late Mesolithic and Early Neolithic societies (United States)

    Berger, Jean-François; Delhon, Claire; Magnin, Frédéric; Bonté, Sandrine; Peyric, Dominique; Thiébault, Stéphanie; Guilbert, Raphaele; Beeching, Alain


    This multi-proxy study of a small floodplain in the Rhone catchment area, at the northern edge of the Mediterranean morphoclimatic system, provides valuable information concerning the impact of mid-Holocene climate variability (8.5-7.0 ka) and the effects of two rapid climatic changes (8.2 and 7.7/7.1 ka) on an alluvial plain, its basin and the first farming societies of the Rhone valley. Around 7.7/7.1 ka, the combined effects of (1) a strong rate of change in insolation and (2) variations in solar activity amplified marine and atmospheric circulation in the north-west Atlantic (Bond event 5b), which imply continental hydrological, soil and vegetation changes in the small catchment area. For this period, strong fluctuations in the plant cover ratio have been identified, related to a regime of sustained and regular fires, as well as abundant erosion of the hill slopes and frequent fluvial metamorphoses which led to braiding of the watercourse in this floodplain. There are few data available to evaluate the impact of natural events on prehistoric communities. This continental archive offers clear multi-proxy data for discussion of these aspects, having 4 cultural layers interbedded in the fluvial sequence (1 Late Mesolithic, 3 Cardial/Epicardial). Earlier data indicate the difficulty in recognizing such cultural features in the low alluvial plains of southern France during the Mesolithic/Early Neolithic transition, which should lead to caution when developing settlement models for this period.

  1. River terraces and alluvial fans: The case for an integrated Quaternary fluvial archive (United States)

    Mather, A. E.; Stokes, M.; Whitfield, E.


    The fluvial archive literature is dominated by research on river terraces with appropriate mention of adjacent environments such as lakes. Despite modern sedimentary basins comprising a significant (>88%) volume of distributive fluvial systems, of which alluvial fans (>1 km, archive community. Published literature is used to examine both thematic and geographical based benefits of alluvial fan research that can assist understanding of Quaternary fluvial archives. 3 regional case studies are presented that illustrate the interaction between alluvial fan and river terrace archives at Quaternary time-scales at 3 different stages of landscape evolution. These are i) continuous mountain front alluvial fans interacting with a non incising but laterally eroding axial fluvial system; ii) alluvial fans which transition into fluvial terraces as sedimentary basins shift from net aggradation to net incision and iii) tributary-junction alluvial fans that develop predominantly within incising river valley systems. A simple conceptual model is proposed to summarise the dynamic role of alluvial fans within this landscape context. The alluvial fans act as potential 'buffers' between hillslopes and river terrace records under 'top down' climate-driven high sediment supply and alluvial fan aggradation, and 'couplers' during periods of less sediment (in relation to water) discharge and alluvial fan incision. These dynamics will change with the addition of 'bottom up' controls such as main river incision, which will typically enhance the coupling effect of both systems.

  2. A nondeforming rhytidectomy incision. (United States)

    Talamas, I


    A new incision for facial rhytidectomy is presented that completely avoids deformation of the frame of the hair and allows the hair to be combed back without showing the scar, which becomes almost completely invisible in most patients if the incision is made at exactly the specified level. Several authors have tried to maintain the normal hairline, but some of their incisions deform the frame of the hair on the sides, higher than the level of the outer corner of the eye, and others go even higher than this point outside of the hairline, making the scar quite visible! The indications and contraindications for this operation and its designed incisions are discussed. These incisions encourage plastic surgeons not to remove any scalp in the rhytidectomy, but only the skin, because it is precisely the removal of scalp instead of skin that deforms the face, unless the amount of scalp tissue removed is very small. These same incisions are indicated for men.

  3. The response of low to moderate sediment supply incised valley systems to episodic sea-level rises

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, M.A.; Anderson, J.B.; Siringan, F.P. (Rice Univ., Houston, TX (United States))


    Low to moderate sediment supply incised valley systems (e.g., the Trinity, Sabine, and Lavaca rivers) are characterized by mud-dominated estuarine fill and by sedimentation that is limited to the valley cut during low sea level. In contrast, within the high sediment supply Brazos valley system substantial sedimentation has occurred between the lowstand valleys for at least the last 7000 years. Within the Trinity/Sabine incised valley system, sand prone facies include fluvial and tidal inlet deposits. Fluvial deposits are relatively uniform in thickness and distribution, while tidal inlets form discontinuous and pod-like deposits. The valley-fill stratigraphy consists of transgressive parasequences, whose bounding flooding surfaces can be mapped with core and high resolution seismic data. Each parasequences is represented by paired upper bay marsh/bayhead delta and tidal inlet/flood tidal delta facies. Coeval shoreline facies are reworked during the sea-level rise that terminates a particular parasequence. Over 200 sediment cores from the study area are used to define the shapes of these sand bodies, and to establish their origin based on grain sizes, sedimentary structures, and faunal assemblages. The stratigraphy interpreted from these low to moderate sediment supply incised valley systems imply sea level rose episodically during the last transgression. Rapid sea-level rises are responsible for development of isolated shelf sand deposits and may correlate to stream piracy events in the nearby Brazos system. Ongoing investigations concentrate on the distal portions of the incised valleys where they become the feeders to shelf margin deposits within the lowstand systems tract.

  4. Internal Structure of the Incised Valley Fill in the Hangzhou Bay,Eastern China and Its Geological Implications

    Institute of Scientific and Technical Information of China (English)

    LIN Chunming; LI Guangyue; WANG Baichang; GU Lianxing; ZHUO Hongchun


    This paper presents the sedimentary facies and formation of the Qiantangjiang and Taihu incised valleys, and the characteristics of shallow gas reservoir distribution, based on a large number of data of drilling, static sounding and chemical analysis obtained from the present Hangzhou Bay coastal plain. The incised valleys were formed during the last glacial maximum and were subsequently filled with fluvial facies during the post-glacial period. All commercial gases are stored in the flood plain sand lenses of the incised valleys.

  5. A theoretical model for fluvial channel response time during time-dependent climatic and tectonic forcing and its inverse applications (United States)

    Goren, Liran


    The fluvial response time dictates the duration of fluvial channel adjustment in response to changing climatic and tectonic conditions. However, when these conditions vary continuously, the channel cannot equilibrate and the response time is not well defined. Here I develop an analytical solution to the linear stream power model of fluvial incision that predicts the channel topography as a function of time-dependent climatic and tectonic conditions. From this solution, a general definition of the fluvial response time emerges: the duration over which the tectonic history needs to be known to evaluate channel topography. This new definition is used in linear inversion schemes for inferring climatic or tectonic histories from river long profiles. The analytic solution further reveals that high-frequency climatic oscillations, such as Milankovitch cycles, are not expected to leave significant fingerprints on the long profiles of fluvially incised detachment-limited rivers.

  6. Channel arrangements and depositional styles in the São Lourenço fluvial megafan, Brazilian Pantanal wetland (United States)

    Assine, Mario Luis; Corradini, Fabrício Anibal; Pupim, Fabiano do Nascimento; McGlue, Michael Matthew


    The Brazilian Pantanal is an extensive lowland tropical basin characterized by the presence of fluvial megafans and seasonally-inundated savanna floodplain wetlands. With an area of about 16,000 km2, the São Lourenço is the second largest megafan in the Pantanal. Three distinct fluvial channel styles that formed at different times during the late Quaternary are found here. A geomorphological and sedimentary assessment of these depositional patterns provides valuable insight on the environmental context of their evolution. New optically stimulated luminescence data indicate that the upper five meters of sediment in the São Lourenço megafan has been accumulating since the late Pleistocene. Ancient fan lobes, located in upper and intermediate fan settings, consist of medium- and coarse-grained fluvial sands and exhibit well-preserved distributary braided paleochannels on their surfaces. As the megafan evolved through time, Pleistocene lobes were incised by a prominent valley filled with Holocene-aged meander belt deposits, which consist of silts interbedded with very fine sands and clays. Currently, the incised valley is a zone of sediment bypass. Modern deposition occurs along the distal toe of the megafan system, where lobes characterized by distributary channel-levee ridges are widespread. These features formed by progradation of avulsion belts into a broad swampy floodbasin, which caused the lower portion of the meander belt to be abandoned. The significant differences observed in intra-fan morphology appear to be linked to the variability in effective precipitation. Fan lobes deposited with braided distributary channels occurred under relatively dry conditions in the late Pleistocene. By contrast, aggradational meander belt deposits and lobes with distributary channel-levee ridges formed during fluctuating precipitation conditions of the Holocene, when the Pantanal emerged from deglacial aridity. Modern lobes form under heavy seasonal flooding and deposition

  7. Lower Vistula fluvial lakes as possible places of deep groundwaters effluence (Grudziądz Basin, North Central Poland) (United States)

    Kordowski, Jaroslaw; Kubiak-Wójcicka, Katarzyna; Solarczyk, Adam; Tyszkowski, Sebastian


    Regarding the outflow the Vistula River is the largest river in the Baltic catchment. In its lower course, below Bydgoszcz, in the Late Holocene Vistula channel adopted an weakly anastomosing fluvial pattern destroyed by intensive human hydrotechnical activity and by the regulation which have intensified about 200 years ago. Channel regulation have left many artificially separated fluvial lakes. Part of them infilled rapidly but the majority have persisted to present day almost unchanged. It has also arised the question: what drives the resistence for silting? To solve the problem there were conducted simultaneous hydrological and geomorphological investigations, because there were two concepts: one that the mineral material is removed from fluvial lakes while high stands by flood waters and second that the material is removed due to high groundwater "exchange" rate when the fluvial lake has a sufficient hydrological connectivity to the main Vistula channel. The Vistula valley crosses morainic plains of the last glaciation. On the average it has about 10 km width and is incised about 70 - 80 m deep, compared to neighbouring plains, dissecting all the Quaternary aquifers. On the floodplain area the Quaternary sediments lay with a layer of only 10-20 m thickness over Miocene and Oligocene sands. In favourable conditions, particularly while a low stand there exists the possibility of Tertiary water migration toward the surface of fluvial lakes provided they have not continuous flood sediments cover on their floors. As an example of such a lake with an intensive water exchange rate by supposed deep groundwaters was chosen the Old Vistula lake (Stara Wisła) near Grudziądz town. The lake has an area of 40 ha, mean depth 1,73 m, maximum depth 8 m, length about 4 km and medium width about 100 m. In the years 2011-2014, with two weeks frequency, in its surficial water layer were conducted measures which included temperature, pH, Eh, suspended matter amount, total and

  8. Significance of Quaternary and Experimental Fluvial Systems to Interpretation of the Stratigraphic Record (United States)

    Blum, M. D.; Martin, J. M.


    Studies of Quaternary and experimental fluvial systems provide significant insight for interpretation of fluvial deposits in the stratigraphic record, ranging from measurement of processes and relevant scales of key architectural elements, to process-based understanding of fluvial systems in sequence stratigraphic models. One key advantage for Quaternary and experimental systems is they commonly provide the ability to test, in a classical verification or falsification sense, interpretations, models and their alternatives that were developed from the stratigraphic record alone. First, scaling relationships developed from Quaternary fluvial deposits can be utilized to constrain interpretations of ancient strata, as well as predict the scale of channel fills, channel-belt sand bodies, and incised valleys. Scaling relationships are defined by power laws, with absolute dimensions that scale to drainage area, water flux, and sediment flux. Width-to-thickness ratios for channel fills range from 10-20:1, whereas channel-belt sand bodies upstream from backwater effects commonly range from 70-300:1, and 20-40:1within the backwater zone, where channel migration is limited. Quaternary incised valleys range from 25-150 m in thickness, and ~5-100 km in width, with width-to-thickness ratios of ~500-800. Scales of Quaternary channel fills and channel-belt sand bodies overlap are consistent with compilations from the ancient record. However, even the smallest Quaternary incised valleys reside in the uppermost part of the domain of published ancient valleys, with ancient examples overlapping significantly with modern channel fills and channel belts. We suggest that many ancient examples have been overinterpreted because of a lack of objective criteria for differentiating channel fills, channel belts, and incised valleys. Second, incised valleys have long played a key role in sequence-stratigraphic interpretations. For incised valleys in the stratigraphic record, either in outcrop or

  9. Fluvial erosion as a mechanism for crater modification on Titan (United States)

    Neish, C. D.; Molaro, J. L.; Lora, J. M.; Howard, A. D.; Kirk, R. L.; Schenk, P.; Bray, V. J.; Lorenz, R. D.


    There are few identifiable impact craters on Titan, especially in the polar regions. One explanation for this observation is that the craters are being destroyed through fluvial processes, such as weathering, mass wasting, fluvial incision and deposition. In this work, we use a landscape evolution model to determine whether or not this is a viable mechanism for crater destruction on Titan. We find that fluvial degradation can modify craters to the point where they would be unrecognizable by an orbiting spacecraft such as Cassini, given enough time and a large enough erosion rate. A difference in the erosion rate between the equator and the poles of a factor of a few could explain the latitudinal variation in Titan's crater population. Fluvial erosion also removes central peaks and fills in central pits, possibly explaining their infrequent occurrence in Titan craters. Although many craters on Titan appear to be modified by aeolian infilling, fluvial modification is necessary to explain the observed impact crater morphologies. Thus, it is an important secondary modification process even in Titan's drier equatorial regions.

  10. Simulations of Fluvial Landscapes (United States)

    Cattan, D.; Birnir, B.


    The Smith-Bretherton-Birnir (SBB) model for fluvial landsurfaces consists of a pair of partial differential equations, one governing water flow and one governing the sediment flow. Numerical solutions of these equations have been shown to provide realistic models in the evolution of fluvial landscapes. Further analysis of these equations shows that they possess scaling laws (Hack's Law) that are known to exist in nature. However, the simulations are highly dependent on the numerical methods used; with implicit methods exhibiting the correct scaling laws, but the explicit methods fail to do so. These equations, and the resulting models, help to bridge the gap between the deterministic and the stochastic theories of landscape evolution. Slight modifications of the SBB equations make the results of the model more realistic. By modifying the sediment flow equation, the model obtains more pronounced meandering rivers. Typical landsurface with rivers.

  11. Fluvial landscapes of the Harappan civilization. (United States)

    Giosan, Liviu; Clift, Peter D; Macklin, Mark G; Fuller, Dorian Q; Constantinescu, Stefan; Durcan, Julie A; Stevens, Thomas; Duller, Geoff A T; Tabrez, Ali R; Gangal, Kavita; Adhikari, Ronojoy; Alizai, Anwar; Filip, Florin; VanLaningham, Sam; Syvitski, James P M


    The collapse of the Bronze Age Harappan, one of the earliest urban civilizations, remains an enigma. Urbanism flourished in the western region of the Indo-Gangetic Plain for approximately 600 y, but since approximately 3,900 y ago, the total settled area and settlement sizes declined, many sites were abandoned, and a significant shift in site numbers and density towards the east is recorded. We report morphologic and chronologic evidence indicating that fluvial landscapes in Harappan territory became remarkably stable during the late Holocene as aridification intensified in the region after approximately 5,000 BP. Upstream on the alluvial plain, the large Himalayan rivers in Punjab stopped incising, while downstream, sedimentation slowed on the distinctive mega-fluvial ridge, which the Indus built in Sindh. This fluvial quiescence suggests a gradual decrease in flood intensity that probably stimulated intensive agriculture initially and encouraged urbanization around 4,500 BP. However, further decline in monsoon precipitation led to conditions adverse to both inundation- and rain-based farming. Contrary to earlier assumptions that a large glacier-fed Himalayan river, identified by some with the mythical Sarasvati, watered the Harappan heartland on the interfluve between the Indus and Ganges basins, we show that only monsoonal-fed rivers were active there during the Holocene. As the monsoon weakened, monsoonal rivers gradually dried or became seasonal, affecting habitability along their courses. Hydroclimatic stress increased the vulnerability of agricultural production supporting Harappan urbanism, leading to settlement downsizing, diversification of crops, and a drastic increase in settlements in the moister monsoon regions of the upper Punjab, Haryana, and Uttar Pradesh.


    Institute of Scientific and Technical Information of China (English)



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  13. 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.


    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

  14. Testing bedrock incision models: Holocene channel evolution, High Cascades, Oregon (United States)

    Sweeney, K. E.; Roering, J. J.; Fonstad, M. A.


    There is abundant field evidence that sediment supply controls the incision of bedrock channels by both protecting the bed from incision and providing tools to incise the bed. Despite several theoretical models for sediment-dependent bedrock abrasion, many investigations of natural channel response to climatic, lithologic, or tectonic forcing rely on the stream power model, which does not consider the role of sediment. Here, we use a well-constrained fluvial channel cut into a Holocene lava flow in the High Cascades, Oregon to compare incision predictions of the stream power model and of the full physics of theoretical models for saltation-abrasion incision by bedload and suspended load. The blocky andesite of Collier lava flow erupted from Collier Cone ~1500 years ago, paving over the existing landscape and erasing fine-scale landscape dissection. Since the eruption, a 6 km stream channel has been incised into the lava flow. The channel is comprised of three alluvial reaches with sediment deposits up to 2 m thick and two bedrock gorges with incision of up to 8 m, with larger magnitude incision in the upstream gorge. Abraded forms such as flutes are present in both gorges. Given the low magnitude and duration of modern snowmelt flow in the channel, it is likely that much of the incision was driven by sediment-laden outburst floods from the terminus of Collier Glacier, which is situated just upstream of the lava flow and has produced two outburst floods in the past 100 years. This site is well suited for comparing incision models because of the relatively uniform lithology of the lava flow and our ability to constrain the timing and depth of incision using the undissected lava surface above the channel as an initial condition. Using a simple finite difference scheme with airborne-Lidar-derived pre-incision topography as an initial condition, we predict incision in the two gorges through time with both stream power and sediment-dependent models. Field observations

  15. Mobile TLS application for fluvial studies (United States)

    Alho, P.; Kukko, A.; Hyyppä, H.; Kaartinen, H.; Hyyppä, J.; Jaakkola, A.


    In fluvial studies, different survey and modelling approaches have been used to study the interaction of landscape and flow processes, including response thresholds, feedback elements and other such complexities, requiring both high-quality topographical and bathymetrical data at different scales. Currently, tachymetry and GPS surveys are widely used in fluvial geomorphology, while more sophisticated survey methods such as close-range photogrammetry and terrestrial laser scanning (TLS) are less common. Static TLS measurements provide a point density, ranging from 100-10000 points/m2 with a root mean square error of ±2 to ±25 mm. Although the TLS system allows the collection of data at a higher resolution and precision than ALS at a lower cost, its area is more limited than the latter method. This area limitation can be improved using mobile laser scanning. The typical requirements for a mobile mapping system (MMS) are that visible objects should be measured to an accuracy of a few centimetres with a maximum speed of 50-60 km h-1 and that desired objects should be collected within a radius of several tens of metres. Recently, it has been reported mobile mapping systems, which are based on laser scanning, the former work including an account of the FGI ROAMER system and a detailed description of its data processing. The boat-based, mobile mapping system (BoMMS, based on FGI ROAMER system) with a laser scanner for fluvial applications allows the derivation of detailed topographical data in river studies. Combined with data acquisition from static terrestrial laser scanning (TLS), boat-based laser scanning enables a totally new field mapping approach for fluvial studies. In this paper, we demonstrate a BoMMS with a laser scanner for fluvial applications. This system enables rapid field surveying with accuracy of approximately 2 cm (relatively sub-centimetre) for river banks, point-bars and other features of the riverine landscape. This application offers a highly

  16. Single incision laparoscopic surgery

    Institute of Scientific and Technical Information of China (English)

    Arun; Prasad


    As a complement to standard laparoscopic surgery and a safe alternative to natural orifice transluminal endoscopic surgery,single incision laparoscopic surgery is gaining popularity.There are expensive ports,disposable hand instruments and flexible endoscopes that have been suggested to do this surgery and would increase the cost of operation.For a simple surgery like laparoscopic cholecystectomy,these extras are not needed and the surgery can be performed using standard ports,instruments and telescopes.Tri...

  17. Holocene fluvial terraces in the Gangkou River Basin of Hengchun Peninsula, Taiwan: implications for sea-level and tectonic controls (United States)

    Chen, Jia-Hong; Chyi, Shyh-Jeng; Ho, Lih-Der; Jen, Chia-Hung; Yen, Jiun-Yee; Lüthgens, Christopher


    The Gangkou River basin is the largest basin in the eastern Hengchun Peninsula, which is the most latest emerged region of the Taiwan orogen. The width of the active channel of Gangkou River is narrow but the valleys from middle to downstream are remarkably wide, which indicates the features of underfit stream. Based on the 14C dates of buried tree trunk and terrace sediments, the preliminary model for the geomorphic evolution of Gangkou River is proposed as: Stage I: The wide spread fine-grained sediments of more than 30-meter-thick was found in the downstream area of drainage basin. The large-scale aggradation event was formed between 12000 to 7000 yr BP in response to the rapid sea-level rise during the late Pleistocene and early Holocene. Stage II: The 15 to 20-meter-high terraces of Gangkou River were formed by the incision and lateral erosion between 7000 to 400 yr BP. The 14C dates of marine terraces, beach rocks and sand dune near the estuary also indicate this erosional stage which could be related to the mid-Holocene climatic shift, tectonic uplift and the stabilized sea-level. Stage III: The 3 to 5-meter-high terraces were formed around 400 yr BP which indicated the low incision rate and the modern fluvial processes. The uplift rates are estimated by the height of river and marine terraces as 1.0 to 1.5 and 1.5 to 2.5 mm/yr respectively. The results indicate the low uplift rate maybe contributed to the underfit stream feature, and the fluvial terraces are responding to sea-level, tectonic and climate controls with different timescale in the Gangkou River. The low uplift rate found in the Gangkou River contradicted to the idea of high tectonic uplift rate in Taiwan.

  18. Fluvial responses to late Quaternary climate change in the Shiyang River drainage system, western China (United States)

    Gao, Hongshan; Li, Zongmeng; Pan, Baotian; Liu, Fenliang; Liu, Xiaopeng


    As a drainage system located in arid western China, the Shiyang River, combined with considerable fluvial strata and landform information, provides an environmental context within which to investigate fluvial responses to late Quaternary climate change. Sedimentological analysis and optically stimulated luminescence (OSL) dating enabled us to reconstruct the processes and fluvial styles of three sedimentary sequences of the Shagou and Hongshui rivers in the Shiyang drainage system. Our results present a variety of river behaviors during the late Quaternary in these areas. In the upstream Shiyang River, Zhangjiadazhuang (ZJDZ) profile of the Shagou was dominated by aggradation and a meandering channel pattern at 10.6-4.2 ka, while a noticeable channel incision occurred at ~ 4.2 ka followed by lateral channel migration. In the downstream Shiyang River, Datugou (DTG) profile of the Hongshui was an aggrading meandering river from 39.7 to 7.2 ka while channel incision occurred at 7.2 ka. Another downstream profile, Wudunwan (WDW) of the Hongshui was also characterized by aggradation from 22.4 to 4.8 ka; however, its channel pattern shifted from braided to meandering at ~ 13 ka. A discernable downcutting event occurred at ~ 4.8 ka, followed by three channel aggradation and incision episodes prior to 1.8 ka. The last 1.8 ka has been characterized by modern channel and floodplain development. The fluvial processes and styles investigated have a close correlation with late Quaternary climate change in the Shiyang River drainage. During cold phases, the WDW reach was dominated by aggradation with a braided channel pattern. During warm phases, the rivers that we investigated were also characterized by aggradation but with meandering channel patterns. Channel incision events and changes of fluvial style occurred mainly during climate transitions.

  19. Fluvial terrace formation along Wyoming's Laramie Range as a response to increased late Pleistocene flood magnitudes (United States)

    Hanson, Paul R.; Mason, Joseph A.; Goble, Ronald J.


    This study evaluates the potential climatic mechanisms involved in fluvial terrace genesis along Wyoming's Laramie Range. We used optical dating methods to determine depositional ages for fluvial fills, and to calculate incision rates for terrace suites along two of the region's larger rivers. Optical ages were determined for the five lowest terrace levels (T5-T1) which were deposited at ˜ 59.6, 39.2, 26.3, 22.7, and 18.5 ka, and incision rates calculated for the two rivers were ˜ 0.29-0.34 m/kyr over the last ˜ 60 kyr. The formation of fluvial terraces in the central Rocky Mountains is commonly attributed to climatically induced changes in sediment input. According to most studies, relatively low incision rates existed during the colder periods of the Pleistocene due to high stream sediment loads, but terraces were formed during warmer interglacial periods when reduced sediment availability facilitated higher incision rates. However, this conceptual model cannot explain the incision records presented here, which show that the streams incised 9-10 m in two to three events during Oxygen Isotope Stage 2, but only 1-2 m during the warmer climates of the last ˜ 18.5 ka. The stream power model we adapted to this setting suggests that late Quaternary streams operated under two basic states. During the colder conditions of the Pleistocene, higher flood magnitudes resulted in higher lateral erosion and incision rates. However, the lower stream discharge common to the warmer interglacial periods resulted in relatively inactive streams when both lateral erosion and incision rates were lowered. This model can explain the high incision rates during the cold conditions of Oxygen Isotope Stage 2, the occurrence of terrace fill ages near cold to warm transitions, and the apparent acceleration in incision rates toward the end of the last glacial cycle. Finally, this study suggests that terrace fill ages and incision rates are similar for the distally glaciated Laramie River

  20. Late Quaternary rates of stream incision in Northeast Peloponnese, Greece (United States)

    Karymbalis, Efthimios; Papanastassiou, Dimitrios; Gaki-Papanastassiou, Kalliopi; Ferentinou, Maria; Chalkias, Christos


    This study focuses on defining rates of fluvial incision for the last 580±5 kyr along valley systems of eight streams that drain the eastern part of the northern Peloponnese. The streams are developed on the uplifted block of the offshore-running Xylokastro normal fault, one of the main faults bounding the southern edge of the Gulf of Corinth half-graben, and have incised a set of ten uplifted marine terraces having an amphitheatric shape. These terraces range in age from 60±5 kyr to 580±5 kyr and have been mapped in detail and correlated with late Pleistocene oxygen-isotope stages of high sea-level stands by previous studies. The terraces were used in this paper as reference surfaces in order to define fluvial incision rates at the lower reaches of the studied streams. To evaluate incision rates, thirty-three topographic valley cross-sections were drawn using fieldwork measurements as well as using a highly accurate (2×2 cell size) Digital Elevation Model (DEM) at specific locations where streams cut down the inner edges of the marine terraces. For each cross-section the ratio of valley floor width to valley height (Vf) and long-term mean stream incision rates were estimated for the last 580±5 kyr, while rock uplift rates were estimated for the last 330±5 kyr. The geomorphic evolution of the valleys on the uplifted block of the Xylokastro fault has been mainly driven by the lithology of the bedrock, sea level fluctuations during the late Quaternary, and incision of the channels due to the tectonic uplift. Stream incision rates range from 0.10±0.1 mm/yr for the last 123±7 kyr to 1.14±0.1 mm/yr for the last 310±5 kyr and are gradually greater from east to west depending on the distance from the trace of the fault. Downcutting rates are comparable with the rock uplift rates, which range from 0.4±0.02 mm/yr to 1.49±0.12 mm/yr, over the last 330±5 kyr.

  1. The inverted Batman incision: a new incision in transcolumellar incision for open rhinoplasty. (United States)

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


    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.

  2. Craniosynostosis incision: scalpel or cautery? (United States)

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


    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.

  3. Transumbilical single-incision laparoscopic hepatectomy: an initial report

    Institute of Scientific and Technical Information of China (English)

    HU Ming-gen; ZHAO Guo-dong; XU Da-bing; LIU Rong


    Transumbilical single-incision laparoscopic surgeries have attracted the attention of surgeon. Here we report a patient with multiple hepatic hemagiomas and symptomatic cholelithiasis who underwent laparoscopic left lateral hepatecomy and left hepatic hemangioma enucleation with single incision followed by cholecystectomy. The duration of the operation was 155 minutes and the blood loss was 100 ml. There were no complications during or after the treatment. This surgical treatment yields a good cosmetic effect and rapid recovery.

  4. Heart bypass surgery incision (image) (United States)

    ... the left part of the chest between the ribs. This incision is much less traumatic than the traditional heart bypass surgery incision which separates the breast bone. Minimally invasive heart bypass surgery allows the patient less pain and a faster recovery.

  5. An Empirical-Conceptual Model for the Formation and Evolution of Incised Coastal Channels: The `Chines' of the Isle of Wight, England. (United States)

    Leyland, J.; Darby, S. E.


    Incised channels are features of disturbed landscapes that are found in all morphoclimatic regions, operating at a range of spatial and temporal scales. Coastal incised channels can be found at various locations around the world where the shoreline morphology consists of cliffs. The channels can cut through a range of cliff materials although the depth of incision may be limited by the erodibility of the lithology. The incised channels that are the focus of this study flow into the sea along the southern coast of the Isle of Wight, which is located close to the southern English shore. This coastline consists of soft cliffs varying in height from 15m to 100m and which are rapidly retreating at rates of up to 2m a-1 due to a combination of wave erosion and landslides. River channels that debouche through these cliffs, which are known locally as `Chines', are deeply (in places 45m) incised and side-wall collapse is a common process. The combination of deep incision (which provides a sheltered environment) and unstable side-wall surfaces provide habitats that support a range of diverse and rare flora (Philonotis marchica, Anthoceros punctatos) and fauna (Psen atratinus, Baris analis, Melitaea cinxi). Understanding the geomorphic evolution of these features is, therefore, of considerable interest from the point of view of the long term management of biodiversity. The Isle of Wight Chines can be considered unusual in that their formation is associated with shoreline encroachment during a period of rising sea-level, whereas most existing models of incised fluvial channel evolution emphasise base-level lowering at a location that is fixed in space. A conceptual model of the sequential stages of morphological evolution within the Chines has been developed by applying a space for time substitution method using empirical data gathered from Chine channel surveys. The model is linked to a theory of Chine growth or decay that is based on analysing the relative balance between

  6. Minimally invasive "pocket incision" aortic valve surgery. (United States)

    Yakub, M A; Pau, K K; Awang, Y


    A minimally invasive approach to aortic valve surgery through a transverse incision ("pocket incision") at the right second intercostal space was examined. Sixteen patients with a mean age of 30 years underwent this approach. The third costal cartilage was either excised (n = 5) or dislocated (n = 11). The right internal mammary artery was preserved. Cardiopulmonary bypass (CPB) was established with aortic-right atrial cannulation in all except the first case. Aortic valve replacements (AVR) were performed in 15 patients and one had aortic valve repair with concomitant ventricular septal defect closure. There was no mortality and no major complications. The aortic cross-clamp, CPB and operative times were 72 +/- 19 mins, 105 +/- 26 mins and 3 hrs 00 min +/- 29 mins respectively. The mean time to extubation was 5.7 +/- 4.0 hrs, ICU stay of 27 +/- 9 hrs and postoperative hospital stay of 5.1 +/- 1.2 days. Minimally invasive "pocket incision" aortic valve surgery is technically feasible and safe. It has the advantages of central cannulation for CPB, preservation of the internal mammary artery and avoiding sternotomy. This approach is cosmetically acceptable and allows rapid patient recovery.

  7. Exhumation and incision history of the Lahul Himalaya, northern India, based on (U-Th)/He thermochronometry and terrestrial cosmogenic nuclide methods (United States)

    Adams, Byron; Dietsch, Craig; Owen, Lewis A.; Caffee, Marc W.; Spotila, James; Haneberg, William C.


    Low-temperature apatite (U-Th)/He (AHe) thermochronology on vertical transects of leucogranite stocks and 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating on strath terraces in the Lahul Himalaya provide a first approximation of long-term (10 4-10 6 years) exhumation rates for the High Himalayan Crystalline Series (HHCS) for northern India. The AHe ages show that exhumation of the HHCS in Lahul from shallow crustal levels to the surface was ~ 1-2 mm/a and occurred during the past ~ 2.5 Ma. Bedrock exhumation in Lahul fits into a regional pattern in the HHCS of low-temperature thermochronometers yielding Plio-Pleistocene ages. Surface exposure ages of strath terraces along the Chandra River range from ~ 3.5 to 0.2 ka. Two sites along the Chandra River show a correlation between TCN age and height above the river level yielding maximum incision rates of 12 and 5.5 mm/a. Comparison of our AHe and surface exposure ages from Lahul with thermochronometry data from the fastest uplifting region at the western end of the Himalaya, the Nanga Parbat syntaxis, illustrates that there are contrasting regions in the High Himalaya where longer term (10 5-10 7 years) erosion and exhumation of bedrock substantially differ even though Holocene rates of fluvial incision are comparable. These data imply that the orogen's indenting corners are regions where focused denudation has been stable since the mid-Pliocene. However, away from these localized areas where there is a potent coupling of tectonic and surface processes that produce rapid uplift and denudation, Plio-Pleistocene erosion and exhumation can be characterized by disequilibrium, where longer term rates are relatively slower and shorter term fluvial erosion is highly variable over time and distance. The surface exposure age data reflect differential incision along the length of the Chandra River over millennial time frames, illustrate the variances that are possible in Himalayan river incision, and highlight

  8. Seismic facies of incised-channel fill deposits of paleo-Seomjin River in the South Sea, Korea (United States)

    Bae, Sung Ho; Kong, Gee Soo; Choul Kim, Dae; Lee, Gwang Soo; Yoo, Dong Geun


    High-resolution (Chirp and Sparker system) seismic profiles and piston core samples were analyzed to investigate the depositional environment of paleo-channel in the continental shelf of South Sea. Approximately 1,940 line-km data of chirp and sparker profiles was acquired. Along with seismic profiles, 20 piston core and 10 box core samples collected in 2015. The paleo-channel of Seomjin River is distributed in the continental shelf, with approximately 109 km long, 800-5,000 m wide, and more than 890 km2. The paleo-channel of meandering and straight type is dominant in the inner shelf while changed to braided type in the outer shelf. The paleo-channels in sparker seismic data formed presumably as fluvial systems when the shelf was exposed during the Last Glacial Maximum (LGM). The seismic facies of incision fill divided into five types basis of an erosional surface and internal seismic reflectors: (1) transparent to semi-transparent incised channel fill, (2) parallel to sub-parallel incised channel fill, (3) complex incised channel fill, (4) divergent incised channel fill, and (5) chaotic incised channel fill. The chaotic incised channel fill deposits are consists of gravel with shell fragments in the outer shelf and indicate the LGM to early transgressive (fluvial lag deposits). The complex incised channel fill deposits are dominated by sand and gravel with shell fragments in the mid to outer shelf. The cores which were obtained above the transparent to semi-transparent and parallel to sub-parallel incised channel fill deposits are dominated by mud. These types are dominant in the upstream (inner shelf). The acoustically transparent zones of this type with low-energy, passively infilling depositional environment, suggest the presence of basin muddy deposits. These muddy sediments were likely deposited during a more advanced stage of the Holocene transgression. Thus, the paleo-channel of Seomjin River is strongly controlled by sea-level change and sediment

  9. Fluvial channels on Titan: Initial Cassini RADAR observations (United States)

    Lorenz, R.D.; Lopes, R.M.; Paganelli, F.; Lunine, J.I.; Kirk, R.L.; Mitchell, K.L.; Soderblom, L.A.; Stofan, E.R.; Ori, G.; Myers, M.; Miyamoto, H.; Radebaugh, J.; Stiles, B.; Wall, S.D.; Wood, C.A.


    Cassini radar images show a variety of fluvial channels on Titan's surface, often several hundreds of kilometers in length. Some (predominantly at low- and mid-latitude) are radar-bright and braided, resembling desert washes where fines have been removed by energetic surface liquid flow, presumably from methane rainstorms. Others (predominantly at high latitudes) are radar-dark and meandering and drain into or connect polar lakes, suggesting slower-moving flow depositing fine-grained sediments. A third type, seen predominantly at mid- and high latitudes, have radar brightness patterns indicating topographic incision, with valley widths of up to 3 km across and depth of several hundred meters. These observations show that fluvial activity occurs at least occasionally at all latitudes, not only at the Huygens landing site, and can produce channels much larger in scale than those observed there. The areas in which channels are prominent so far amount to about 1% of Titan's surface, of which only a fraction is actually occupied by channels. The corresponding global sediment volume inferred is not enough to account for the extensive sand seas. Channels observed so far have a consistent large-scale flow pattern, tending to flow polewards and eastwards. ?? 2008.

  10. Fluvial dissection, isostatic uplift, and geomorphological evolution of volcanic islands (Gran Canaria, Canary Islands, Spain) (United States)

    Menéndez, Inmaculada; Silva, Pablo G.; Martín-Betancor, Moises; Pérez-Torrado, Francisco José; Guillou, Hervé; Scaillet, S.


    Digital analysis of torrential gullies ('barrancos') deeply incised into the volcanic Island of Gran Canaria (Canary Islands) allows us to extract the longitudinal profiles and pre-incision surfaces for individual basins, from which morphometric parameters (length, elevation, area, slope) have been calculated. Other derived parameters, such as ridgeline profiles, maximum incision values, volume removed by fluvial erosion, geophysical relief and isostatic uplift, have also been computed. Based on K/Ar ages for the island, well-constrained incision-uplift rates have been calculated by means of the combination of different methodological approaches commonly used in orogens and large mountain ranges. The geomorphological and morphometric analyses reveal that the island is clearly divided into four environmental quadrants determined by the combination of a couple of key-factors: the age of the volcanic surfaces and the climatic conditions. These factors determine a young sector covered with Plio-Quaternary platform-forming lavas (finished at 1.9-1.5 Ma) evolving under contrasting wet (NE) to dry (SE) climates, and an older sector, conserving the residual surfaces of the Miocene shield building (14.5-8.7 Ma) at the ridgelines, also subjected to wet (NW) and dry (SW) climates. Incision is related to the age zonation of the island. Maximum incisions (< 1200 m) are logically recorded in the older SW sector of the island, but incision rates are directly related to the climatic zonation, with maximum mean values in the wet Northern quadrants (0.18-0.12 mm/yr). The evaluation of the material removed by fluvial erosion for individual basins allows us to assess the consequent theoretical isostatic response in the different sectors of the island. The obtained uplift rates indicate that water availability (by drainage area and elevation) is a relevant controlling factor: the records from the wet Northern sectors show uplift values of between 0.09 and 0.03 mm/yr, whereas in the

  11. Towards a phoenix phase in aeolian research: shifting geophysical perspectives from fluvial dominance

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey J [Los Alamos National Laboratory; Field, Jason P [UNIV OF ARIZONA; Breshears, David D [UNIV OF ARIZONA


    Aeolian processes are a fundamental driver of earth surface dynamics, yet the importance of aeolian processes in a broader geosciences context may be overshadowed by an unbalanced emphasis on fluvial processes. Here we wish to highlight that aeolian and fluvial processes need to be considered in concert relative to total erosion and to potential interactions, that relative dominance and sensitivity to disturbance vary with mean annual precipitation, and that there are important scale-dependencies associated with aeolian-fluvial interactions. We build on previous literature to present relevant conceptual syntheses highlighting these issues. We then highlight the relative investments that have been made in aeolian research on dust emission and management relative to that in fluvial research on sediment production. Literature searches highlight that aeolian processes are greatly understudied relative to fluvial processes when considering total erosion in different environmental settings. Notably, within the USA, aeolian research was triggered by the Dust Bowl catastrophe of the 1930s, but the resultant research agencies have shifted to almost completely focusing on fluvial processes, based on number of remaining research stations and on monetary investments in control measures. However, numerous research issues associated with intensification of land use and climate change impacts require a rapid ramping up in aeolian research that improves information about aeolian processes relative to fluvial processes, which could herald a post-Dust Bowl Phoenix phase in which aeolian processes are recognized as broadly critical to geo- and environmental sciences.

  12. Incision for pleural tissue biopsy (image) (United States)

    ... the pleural tissue is removed through a surgical incision in the chest. After the sample is obtained, a chest tube is placed and the incision is closed with stitches. Abnormal results may indicate ...

  13. Contrasting fluvial styles of the Paraguay River in the northwestern border of the Pantanal wetland, Brazil (United States)

    Assine, Mario Luis; Silva, Aguinaldo


    The Upper Paraguay drainage basin is situated mainly in west-central Brazil, near the Bolivian border. Flowing from north to south, the Paraguay is the trunk river of an alluvial depositional tract characterized by complex geomorphologic zonation that resulted from an intricate geologic evolution since the Late Pleistocene. This paper focuses on the geomorphology of the Paraguay River at the northwestern border of the Pantanal wetland, where two broad geomorphologic zones were distinguished. North from the Pantanal wetland, the Paraguay River flows in an aggradational fluvial plain, 5 km wide and incised into older alluvial deposits. The river exhibits a meandering style over most of its course, but sinuosity drops from 2.2 to 1.1 near the northwest border of the Pantanal wetland where the river has been forming the Paraguay fluvial megafan since the Late Pleistocene. The river deflects 90° eastward at the entrance into the Pantanal, changing its fluvial style because of a progressive loss of confinement downstream of the point where the river reaches lowland plains. The river becomes more sinuous, adopts a distributary pattern within the wetland and brings about the creation of the modern depositional lobe characterized by higher topographic gradient and active sedimentation likely linked to increased accommodation space allowing progradation. Fluvial discharge diminishes in the Pantanal wetland because of channel overbank flow during the rainy season and frequent levee crevassing. Avulsion belts and channel-levee complex are preserved on the floodplain as relict forms. South of the convergence of the two main channels that define the Taiamã Island, a loss of gradient marks the base of the depositional lobe. Further downstream, the Paraguay River returns to a meandering fluvial style, but crossing a large fluvial plain populated by hundreds of small lakes and seasonally flooded that characterizes the Pantanal wetland.

  14. Tipping points in Anthropocene fluvial dynamics (United States)

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


    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

  15. SMART micro-scissors based precise incision (United States)

    Park, Hyun-Cheol; Yeo, Chaebeom; Song, Cheol


    Hand tremor reduction is important to achieve stable micro manipulation of the tool tip. A micro-scissors can be used for cutting delicate tissues safely. Here, we implement an OCT distance sensor guided SMART micro-scissors which could incise micro-surgical targets precisely and horizontally. Compared to freehand incision, it demonstrates enhanced incision performance on dry phantoms with great tremor suppression.

  16. River Incision and Knickpoints on the Flank of the Yellowstone Hotspot — Alpine Canyon of the Snake River, Wyoming (United States)

    Tuzlak, D.; Pederson, J. L.


    Understanding patterns of deformation and testing geophysical models in the dynamic region of the Yellowstone Hotspot requires Quaternary-scale records of incision and uplift, which are currently absent. This study examines fluvial terraces and longitudinal-profile metrics along Alpine Canyon of the Snake River, WY. Because the Snake is the only regional river crossing from the uplifting Yellowstone Plateau and flowing into the subsiding Eastern Snake River Plain, it provides an opportunity to investigate both ends of the phenomenon. Field observations through Alpine Canyon indicate that Pleistocene incision rates in this region are relatively high for the interior western U.S., that the river switches between bedrock and alluvial forms, and that incision/uplift is not uniform. Two endmembers of regional deformation may be tested: 1) the arch of high topography surrounding Yellowstone is uplifting and terraces converge downstream as incision rates decrease towards the Snake River Plain, or 2) baselevel fall originates at the subsiding Snake River Plain and terraces diverge as incision rates increase downstream. Datasets include surficial mapping, rock strength measurements, surveying of the longitudinal profile and terraces using RTK-GPS, optically stimulated luminescence dating of fluvial-terrace deposits, and investigation of drainages through ksn and χ analyses. Initial results indicate that there are four primary terrace deposits along the canyon, three of which are timed with glacial epochs. Considering the relative heights of terrace straths and preliminary ages, incision rates are indeed relatively high. There is a major knickzone covering the last 15 km of the canyon that is also reflected in tributary profiles and is consistent with a wave of incision propagating upstream, favoring the second endmember of active baselevel fall downstream.


    ABAID, Rafael Antoniazzi; CECCONELLO, Ivan; ZILBERSTEIN, Bruno


    Background Laparoscopic cholecystectomy has traditionally been performed with four incisions to insert four trocars, in a simple, efficient and safe way. Aim To describe a simplified technique of laparoscopic cholecystectomy with two incisions, using basic conventional instrumental. Technique In one incision in the umbilicus are applied two trocars and in epigastrium one more. The use of two trocars on the same incision, working in "x" does not hinder the procedure and does not require special instruments. Conclusion Simplified laparoscopic cholecystectomy with two incisions is feasible and easy to perform, allowing to operate with ergonomy and safety, with good cosmetic result. PMID:25004296

  18. River Incision, Sediment Storage, and Sediment Residence Times at the Western Tibetan Plateau Margin (United States)

    Bloethe, J. H.; Munack, H.; Fülling, A.; Resentini, A.; Garzanti, E.; Kubik, P.; Korup, O.


    Intermediate sediment storage protects underlying bedrock from incision, buffers sediment delivery from adjacent hillslopes and provides the source for potentially catastrophic sediment release. Along the western Tibetan plateau margin, broad alluviated valleys host large valley fills. Besides sediment storage in major valleys, deeply incised bedrock gorges also have the potential to store sediment for > 104 yrs, even though they are typically portrayed as conveyor belts for incoming sediment. Here we report on cyclic aggradation and re-incision of fluvial terraces near the Tibetan plateau margin in the Ladakh and Zanskar Ranges, NW Himalaya, India. Recently reported 10Be-derived bedrock incision rates of up to 3 mm/yr suggest locally focused fast incision that contrasts with the low (~0.02 mm/yr) denudation rates of this dry high-altitude mountain desert. We combine Optically Stimulated Luminescence (OSL) and 10Be dating techniques, provenance analyses and morphometric analyses of digital elevation models (DEMs), in order to understand the Quaternary evolution of the region and to estimate sediment storage and residence times. We present the first OSL-derived dataset of fluvial fill terrace ages in the lower Zanskar gorge, a major tributary of the upper Indus River. These data are complemented by new 10Be exposure ages from fluvially polished surfaces and a 10Be depth profile of a fluvial terrace situated at the Zanskar-Indus confluence. Our data indicate at least two cycles of aggradation and re-incision. OSL ages from a terrace level 35 m above the river point to a phase of aggradation between 50 ka and 20 ka, which we attribute either to a late- or postglacial sediment pulse from the Zanskar headwaters, and/or to natural damming downstream. Preliminary results for the 10Be depth profile from the top of a terrace ~160 m above river level suggest a deposition age of > 100 ka, dating an older aggradation cycle. This higher terrace level is also present in the

  19. The fluvial system response to abrupt climate change during the last cold stage: the Upper Pleistocene River Thames fluvial succession at Ashton Keynes, UK (United States)

    Lewis, S. G.; Maddy, D.; Scaife, R. G.


    The last interglacial-glacial cycle (125-10 ka BP) is characterised by numerous rapid shifts in global climate on sub-Milankovitch timescales, recorded in the ocean and ice core records. These climatic fluctuations are clearly recorded in those European terrestrial sedimentary sequences that span this time period without interruption. In the UK, only fragmentary Upper Pleistocene sequences exist, mainly within the fluvial archive of the major river systems such as the Thames. The response of the upper River Thames to abrupt fluctuations in climate is documented in the fluvial sediments beneath the Floodplain Terrace (Northmoor Member of the Upper Thames Formation) at Ashton Keynes, Wiltshire. A number of criteria are set out by which significant changes in the fluvial system may be established from the sedimentological, palaeoecological and geochronological information contained within the succession. The sedimentary succession is divisible into four facies associations, on the basis of their sedimentology and bounding surface characteristics. These represent distinct phases of fluvial activity at the site and allow changes in fluvial style to be inferred. Palaeoecological reconstructions from pollen analysis of peats within the sequence provides an indication of the nature and direction of Late Glacial environmental change and optically stimulated luminescence and radiocarbon dating methods provide chronological control on the sequence. These data suggest that major changes in fluvial style are recorded within the succession, which can be related to the climatic fluctuations that took place on the oxygen isotope stage 5a/4 transition (approximately 70 ka BP) and the Devensian Late Glacial climatic warm-cold-warm oscillation (13-11 ka BP). The changes in fluvial style are a result of variations in sediment supply to the river resulting from changes in slope stability, vegetation cover and cold-climate mass movement processes and variations in discharge regime

  20. Fluvial experiments using inertial sensors. (United States)

    Maniatis, Georgios; Valyrakis, Manousos; Hodge, Rebecca; Drysdale, Tim; Hoey, Trevor


    During the last four years we have announced results on the development of a smart pebble that is constructed and calibrated specifically for capturing the dynamics of coarse sediment motion in river beds, at a grain scale. In this presentation we report details of our experimental validation across a range of flow regimes. The smart pebble contains Inertial Measurements Units (IMUs), which are sensors capable of recording the inertial acceleration and the angular velocity of the rigid bodies into which they are attached. IMUs are available across a range of performance levels, with commensurate increase in size, cost and performance as one progresses from integrated-circuit devices for use in commercial applications such as gaming and mobile phones, to larger brick-sized systems sometimes found in industrial applications such as vibration monitoring and quality control, or even the rack-mount equipment used in some aerospace and navigation applications (which can go as far as to include lasers and optical components). In parallel with developments in commercial and industrial settings, geomorphologists started recently to explore means of deploying IMUs in smart pebbles. The less-expensive, chip-scale IMUs have been shown to have adequate performance for this application, as well as offering a sufficiently compact form-factor. Four prototype sensors have been developed so far, and the latest (400 g acceleration range, 50-200 Hz sampling frequency) has been tested in fluvial laboratory experiments. We present results from three different experimental regimes designed for the evaluation of this sensor: a) an entrainment threshold experiment ; b) a bed impact experiment ; and c) a rolling experiment. All experiments used a 100 mm spherical sensor, and set a) were repeated using an equivalent size elliptical sensor. The experiments were conducted in the fluvial laboratory of the University of Glasgow (0.9 m wide flume) under different hydraulic conditions. The use of

  1. Fluvial and glacial implications of tephra localities in the western Wind River basin, Wyoming, U. S. A

    Energy Technology Data Exchange (ETDEWEB)

    Jaworowski, C. (Univ. of Wyoming, Laramie, WY (United States). Dept. of Geology)


    Examination of Quaternary fluvial and glacial deposits in the western Wind River Basin allows a new understanding of the Quaternary Wind River fluvial system. Interbedded fluvial sediments and volcanic ashes provide important temporal information for correlation of Quaternary deposits. In the western Wind River Basin, six mid-Pleistocene localities of tephra, the Muddy Creek, Red Creek, Lander, Kinnear, Morton and Yellow Calf ashes are known. Geochronologic studies confirm the Muddy Creek, Red Creek, Kinnear and Lander ashes as the 620--650ka Lava Creek tephra from the Yellowstone region in northwestern Wyoming. The stratigraphic position and index of refraction of volcanic glass from the Morton and Yellow Calf ashes are consistent with identification as Lava Creek tephra. Approximately 350 feet (106 meters) above the Wind River and 13 miles downstream from Bull Lake, interbedded Wind River fluvial gravels, volcanic glass and pumice at the Morton locality correlate to late (upper) Sacajawea Ridge gravels mapped by Richmond and Murphy. Associated with the oxygen isotope 16--15 boundary, the ash-bearing terrace deposits reveal the nature of the Wind River fluvial system during late glacial-early interglacial times. The Lander and Yellow Calf ashes, are found in terrace deposits along tributaries of the Wind River. Differences in timing and rates of incision between the Wind River and its tributary, the Little Wind River, results in complex terrace development near their junction.

  2. Exit and Paradise Creek Fluvial Features, 1950 (United States)

    U.S. Geological Survey, Department of the Interior — This dataset presents a delineation of the maximum extent of fluvial occupation detectable from vegetation patterns at Exit and Paradise Creeks in Kenai Fjords...

  3. Experimental Studies of the Fluvial System. (United States)


    drainage basins, alluvial fans, fan deltas, experiments, geomorphic, sedimentology , placers *w 20. ATRACr (Cktma -m reverse ab if neceeiv d IdentIfy by... sedimentology . A monograph has been prepared that SDD , 1473 Era’noNOF)MOV6SISOSOLETE UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (lhen Data...LANDFORMS AND SEDIMENTOLOGY 9) ALLUVIAL FANS EXPEP1-1EWAL FtD I ES Experimental Procedure FLUVIAL FAN EXPERIMT TT Fluvial Fan Evolution Growth Patterns Growth

  4. Impact of rock uplift on rates of late Cenozoic Rocky Mountain river incision (United States)

    Riihimaki, Catherine A.; Anderson, Robert S.; Safran, Elizabeth B.


    The high relief of the modern Rocky Mountain landscape formed in the late Cenozoic by downcutting of a fluvial network that links a series of easily eroded sedimentary basins across relatively resistant crystalline cores of adjacent ranges. Using a numerical model of fluvial erosion and the flexural isostatic response to the associated unloading, we first calculate the expected pattern and pace of incision caused by rock uplift related to migration of the Yellowstone hot spot and to growth of the northern portion of the Rio Grande rift. Calculated incision rates are <60 m/Myr, and total depth of erosion of sedimentary basins is <300 m, well below the long-term incision rates and amounts of erosion interpreted from the geologic record. Broad-scale tilting of the region toward the east, accomplished by a gradient in rock uplift of ˜1 km along the north-south axis of the central Rockies, declining to zero 1000 km to the east, can account for the additional erosion needed to match observations. In each modeling scenario, stream incision is nonsteady, with rock uplift outpacing erosion for <1 Myr in perimeter basins and 1-5 Myr in interior basins. Three factors dominate the spatial and temporal pattern of regional landscape evolution: (1) the time since uplift began, (2) the uplift pattern, and (3) the distribution of relatively resistant bedrock within the region. Our results suggest that the spatial variability in late Cenozoic exhumation can be explained by a long-lived transience in the stream network response to these various late Cenozoic geophysical events.

  5. Modified tubularized incised plate urethroplasty

    Directory of Open Access Journals (Sweden)

    Shivaji Mane


    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.

  6. Supra-Pubic Single Incision Cholecystectomy


    Hagen, Monika E.; Wagner, Oliver J.; Thompson, Kari; Jacobsen, Garth; Spivack, Adam; Wong, Brian; Talamini, Mark; Horgan, Santiago


    Introduction Surgery is moving towards less invasive and cosmetically superior approaches such as single incision laparoscopy (SIL). While trans-umbilical SIL is gaining popularity, incisions may lead to post-operative deformations of the umbilicus and the possibility of an increased rate of incisional hernias. Access within the pubic hairline allows preservation of the umbilicus and results in a scar which is concealed within the pubic hair. Methods Supra-pubic single incision cholecystectom...

  7. Degradation of the Mitchell River fluvial megafan by alluvial gully erosion increased by post-European land use change, Queensland, Australia (United States)

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


    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

  8. High-resolution fluvial records of Holocene environmental changes in the Sahel: the Yamé River at Ounjougou (Mali, West Africa) (United States)

    Lespez, L.; Le Drezen, Y.; Garnier, A.; Rasse, M.; Eichhorn, B.; Ozainne, S.; Ballouche, A.; Neumann, K.; Huysecom, E.


    The Yamé river, in the Bandiagara Plateau, Dogon Country, Mali, is characterised by extensive alluvial sedimentary records, particularly in the 1 km long Ounjougou reach where Holocene floodplain pockets are inset in the Pleistocene formations. These alluvial records have been investigated via geomorphologic fieldwork and sedimentologic and micromorphologic analyses and are supported by 79 radiocarbon dates. The alluvial deposits of the valley floor correspond to a vertical accretion of 3-10 m. The reconstruction of fluvial style changes provides evidence of four main aggradation periods. From 11,500 to 8760 cal. BP, the alluvial architecture and grain-size parameters indicate a wandering river. This period included phases of pulsed high-energy floods and avulsion related to a northward shift of the summer monsoon to around 14°N after 11,500 cal. BP. From 7800 to 5300 cal. BP, a swampy floodplain environment with standing water pools within a Sudanian savanna/woodland mosaic corresponds to the culmination of the Holocene humid period. From 3800 cal. BP onwards, rhythmic sedimentation attests to an increase in the duration and/or intensity of the dry season, giving a precise date for the local termination of the Holocene Optimum period. During the last two millennia and for the first time during the Holocene, the alluvial formations are progressively restricted whereas the colluvial deposits increase, indicating strong soil erosion and redeposition within the watershed related to an increase in human impact. Four major periods are characterised by incision (I1: ante 11,500, I2: 8760-7800; I3: 6790-6500 cal. BP; I4; 2400-1700 cal. BP) pointing to dramatic changes in fluvial style. They result from high-energy flood flows during dry spells and confirm the capacity of the floodplain pocket in the upstream reach of the Sahelian belt to record rapid Holocene climatic change.

  9. Millennial-scale climatic fluctuation in the fluvial record during MIS3: Very high-resolution seismic images from NE Hungary (United States)

    Cserkész-Nagy, Ágnes; Sztanó, Orsolya


    Alluvial architectures of a meandering river existing in MIS3 were observed on very high-resolution (VHR) single-channel waterborne seismic profiles, 20-30 m below the Tisza River in the Pannonian Basin (Hungary). The study investigated the spatial and temporal variations of two, more than 2 km-long continuous series of inclined reflections interpreted as laterally accreted point bar complexes. The phases of natural meander migration were reconstructed in 3D based on the changes in the geometry and dip of the inclined reflections. A channel-forming discharge curve extending over approximately 2.5 ky was calculated by using paleo-width and depth data derived from the lateral accretion surfaces. Systematic analysis of the geometrical variations coupled with the discharge curve evaluation on each point bar complexes indicates millennial-scale discharge fluctuations 40-50 ky ago, to that the river responded principally by incision and infilling. The primary periodicity, comparable to the sub-Milankovitch cycles, is superimposed by shorter periods: ca. 500-year cycles reflect the phases of unidirectional meander development, while the smallest ones reflect the recurrence interval (150-200 years) of the highest floods. River-bed incisions happened step-by-step related to extreme floods, when the meander development also changed. The smaller-scale and more rapid fluctuations within a development unit were represented in variations of the channel width. Although the poor geochronology of the sandy fluvial deposits cannot allow any direct correlation to the climatostratigraphic events, the millennial-scale climate variations of MIS3 were pronouncedly characteristic in the discharge fluctuations.

  10. Patient Satisfaction with Postaural Incision Site

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    George Barrett


    Full Text Available Introduction. Controversy exists over the optimum incision placement when performing ear surgery via the postauricular approach. Little is known about the impact of incision placement on future comfort in wearing audio or visual aids or the effect on the minor auricular muscles cut in the approach. Objective. (1 To establish patient satisfaction with their postauricular surgical incision, and to establish the impact on comfort wearing hearing or visual aids. (2 To establish whether patients’ voluntary ear movements were affected by surgery. Materials and Methods. In January 2014, questionnaires were sent to 81 patients who underwent mastoid surgery requiring a postauricular incision between January 2004 and December 2012. The incision placement was broadly the same for all patients as they were operated on by the same surgeon (or under his supervision. The incision is sited far posteriorly at the hairline. Results. 42 (52% of the patients contacted responded. 80% of patients wearing glasses reported no discomfort or problems associated with their incision. 82% of patients who wear hearing aids were comfortable. Only 1 of the 5 patients who could move their ears preoperatively noticed a change afterwards. Conclusion. A hairline incision is well tolerated by most of the patients.

  11. Paleo-fluvial sedimentation on the outer shelf of the East China Sea during the last glacial maximum

    Institute of Scientific and Technical Information of China (English)

    WANG Zhongbo; YANG Shouye; ZHANG Zhixun; LAN Xianhong; GU Zhaofeng; ZHANG Xunhua


    Evidence from lithology,foraminiferal assemblages,and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on the outer shelf of the East China Sea.The paleo-fluvial deposits consist of river channel facies and estuarine incised-valley-filling facies.Different reflections on the seismic profile across core SFK-1 suggest that the river channels shifted and overlapped.River channel deposition formed early in the LGM when sea level fell and the estuary extended to the outer shelf.Channel sediments are yellowish-brown in color and rich in foraminifera and shell fragments owing to the strong tidal influence.Following the LGM,the paleo-river mouth retreated and regressive deposition of estuarine and incised-valley-filling facies with an erosion base occurred.The river channel facies and estuarine incised-valley-filling facies have clearly different sedimentary characteristics and provenances.The depositional environment of the paleo-river system on the wide shelf was reconstructed from the foraminiferal assemblages,CaCO3 content and Ca/Ti ratio.The main results of this study provide further substantial constraints on the recognition of late Quaternary stratigraphy and land-sea interactions on the ECS shelf.

  12. The fluvial record of climate change. (United States)

    Macklin, M G; Lewin, J; Woodward, J C


    Fluvial landforms and sediments can be used to reconstruct past hydrological conditions over different time scales once allowance has been made for tectonic, base-level and human complications. Field stratigraphic evidence is explored here at three time scales: the later Pleistocene, the Holocene, and the historical and instrumental period. New data from a range of field studies demonstrate that Croll-Milankovitch forcing, Dansgaard-Oeschger and Heinrich events, enhanced monsoon circulation, millennial- to centennial-scale climate variability within the Holocene (probably associated with solar forcing and deep ocean circulation) and flood-event variability in recent centuries can all be discerned in the fluvial record. Although very significant advances have been made in river system and climate change research in recent years, the potential of fluvial palaeohydrology has yet to be fully realized, to the detriment of climatology, public health, resource management and river engineering.

  13. Fluvial adjustment to changing base-level and climate over the last glacial-interglacial cycle in sub-tropical Australia (United States)

    Croke, Jacky; Larsen, Annegret; Thompson, Chris


    Continental-margin fluvial systems are often found to be under the influence of both upstream (climate) and downstream (sea level) controls. In Australia, relatively little is known about fluvial adjustment in the upper reaches of large continental drainage systems. In the tectonically-stable setting of eastern Australia, climate is typically seen as the dominant factor governing fluvial response over the timescale of Quaternary glacial/interglacial cycles. This study uses a 30m record of valley alluviation in the lower reaches of Lockyer Creek, a key tributary of the mid-Brisbane River in SEQ, to document (a) the timing of fluvial response to both sea level and climate change, and (b) the nature of the river's response to that change, over the past 230 ka. Chronostratigraphic units within the deep valley fill sequences reveal seven phases of channel incision and aggradation spanning the past 230 ka. The lateral and vertical extent of major valley fill units indicates a switch in depositional style from valley-wide coarse bedload deposition to narrower channel belt, fine-grained aggradation sometime after 120 ka. The preservation of multiple-age channel deposits across the wide valley floor indicates successive channel avulsion over this time-scale. Episodes of channel incision are reasonably aligned with sea level low stands during Marine Isotope Stage (MIS) 7, 6 and 3 where incision to bedrock over depths of 25 to 30 m occurred. However later episodes of channel incision dated to between 27-12 ka either pre-, or post-date the last glacial low stand. The majority of the valley fill in the lower Lockyer consists of fine-grained alluvia which reflect restricted lateral channel mobility due to either, or both, bedrock or fine-grained alluvial confinement. When viewed within the context of past glacial/interglacial Quaternary oscillations, the record confirms a progressively drying continent based on the caliber of bedload material and lateral channel extent.

  14. The linkages among hillslope-vegetation changes, elevation, and the timing of late-Quaternary fluvial-system aggradation in the Mojave Desert revisited


    J. D. Pelletier


    Valley-floor-channel and alluvial-fan deposits and terraces in the southwestern US record multiple episodes of late-Quaternary fluvial-system aggradation and incision. Perhaps the most well-constrained of these episodes took place from the latest Pleistocene to the present in the Mojave Desert. One hypothesis for this episode – i.e., the paleovegetation-change hypothesis (PVCH) – posits that a reduction in hillslope vegetation cover associated with the transition from Pleist...

  15. Fluvial fan evolution during Late Quaternary climate changes: field and chronological constraints from the Indo-Gangetic basin (United States)

    Singh, A.; Gupta, S.; Sinha, R.; Densmore, A.; Thomsen, K. J.; Nayak, N.; Joshi, S. K.; van Dijk, W. M.; Buylaert, J. P.; Mondal, S.; Kumar, D.; Mason, P. J.; Murray, A. S.; Kumar, M.; Shekhar, S.; Rai, S. P.


    The stratigraphic evolution of fluvial fans is to a large extent governed by channel avulsion. Spatial variations in alluvial architecture are influenced by avulsion magnitude and frequency. However due to the absence of long-term chronostratigraphic records of fan stratigraphy, it has proved difficult to test patterns of fan evolution against records of climate variability. In order to understand the processes of channel avulsion during fan evolution, it is important to determine the spatio-temporal pattern of fluvial channel aggradation, incision, and migration. In this study, we reconstruct the shallow sub-surface alluvial stratigraphy of fluvial fan systems formed by the major Himalayan rivers, the Sutlej and Yamuna, in the northwestern Indo-Gangetic basin. We map the spatial distribution of channel sand bodies deposited by these rivers and develop a chronostratigraphic model for the fluvial succession in a depositional dip perpendicular transect. Sediment cores up to ~50 m deep along two transects are used to reconstruct the shallow stratigraphy of the fan systems. Discontinuous channel sand bodies are separated by floodplain fines which occasionally show weak pedogenesis that mark the end of episodes of channel aggradation. Optically stimulated luminescence (OSL) dating is used to bracket the timing of channel-filling episodes, and their spatial distribution. Mapping of sand bodies coupled with chronostratigraphic constraints allows reconstruction of channel migration patterns and their timing across the Sutlej-Yamuna fans. Chronostratigraphy permits temporal correlation with published measures of monsoon variability. We find that fluvial aggradation at the western end of studied transects, near the middle of the Sutlej fan, terminated around ~20 ka. We also show that abandonment of the paleo-Sutlej and major fan-scale avulsion occurred after ~15 ka, and was followed by formation of incised valleys that confined the modern fluvial system in northwestern Indo

  16. Late Quaternary tectonic landforms and fluvial aggradation in the Saryu River valley: Central Kumaun Himalaya (United States)

    Kothyari, Girish Ch.; Luirei, Khayingshing


    The present study has been carried out with special emphasis on the aggradational landforms to explain the spatial and temporal variability in phases of aggradation/incision in response to tectonic activity during the late Quaternary in the Saryu River valley in central Kumaun Himalaya. The valley has preserved cut-and-fill terraces with thick alluvial cover, debris flow terraces, and bedrock strath terraces that provide signatures of tectonic activity and climate. Morphostratigraphy of the terraces reveals that the oldest landforms preserved south of the Main Central Thrust, the fluvial modified debris flow terraces, were developed between 30 and 45 ka. The major phase of valley fill is dated between 14 and 22 ka. The youngest phase of aggradation is dated at early and mid-Holocene (9-3 ka). Following this, several phases of accelerated incision/erosion owing to an increase in uplift rate occurred, as evident from the strath terraces. Seven major phases of bedrock incision/uplift have been estimated during 44 ka (3.34 mm/year), 35 ka (1.84 mm/year), 15 ka (0.91 mm/year), 14 ka (0.83 mm/year), 9 ka (1.75 mm/year), 7 ka (5.38 mm/year), and around 3 ka (4.4 mm/year) from the strath terraces near major thrusts. We postulate that between 9 and 3 ka the terrain witnessed relatively enhanced surface uplift (2-5 mm/year).

  17. Autogenic incision and terrace formation resulting from abrupt late-glacial base-level fall, lower Chippewa River, Wisconsin, USA (United States)

    Faulkner, Douglas J.; Larson, Phillip H.; Jol, Harry M.; Running, Garry L.; Loope, Henry M.; Goble, Ronald J.


    stream systems would have led to renewed knickpoint migration and incision when floods of sufficient magnitude to breach the channel armor occurred. Minimal floodplain development along the upper section of the present-day LCR, along with the channel morphology of an unstable wandering gravel-bed river immediately downstream from it, suggest that the river is still responding to the base-level falls that happened many millennia ago. The autogenic controls on the LCR's response to UMR incision are a direct consequence of the thick fills of noncohesive sediment that accumulated in its valley and the valleys of its tributary streams during the Late Wisconsinan, making the LCR a prime example of a former proglacial river that remains a paraglacial fluvial system.

  18. Bathymetry of Lake Lisan controls late Pleistocene and Holocene stream incision in response to base level fall (United States)

    Davis, Michael; Matmon, Ari; Zilberman, Ezra; Porat, Naomi; Gluck, Daniel; Enzel, Yehouda


    This paper examines the millennial-scale evolution of the longitude profile of Nahal (Wadi) Zin in the Dead Sea basin in the northern Arava valley, Israel. Nahal Zin has incised ~ 50 m into relatively soft late Pleistocene Lake Lisan sediments. Incision was forced by the regressive (> 10 km) lake level fall of a total of > 200 m of Lake Lisan from its highest stand at ~ 25 ka and exposure of the lake-floor sediments to fluvial and coastal processes. Alluvial cut terraces of the incising channel are well preserved along the 17.5 km of the lowermost reach of Nahal Zin. At its outlet into the Dead Sea basin, Nahal Zin deposited a Holocene alluvial fan at the base of a 10-80 m high escarpment in unconsolidated sediments. The escarpment is associated with the Amazyahu fault, which forms the southern structural boundary of the present Dead Sea basin. Geomorphic mapping, optically stimulated luminescence (OSL) ages, and soil stratigraphy allowed correlation of terrace remnants and reconstruction of several past longitudinal profiles of Nahal Zin and its incision history. Together with the published lake level chronology, these data provide an opportunity to examine stream incision related to base level lowering at a millennial scale. OSL ages of the terraces fit relatively well with the established lake level chronology and follow its regression and fall. For a few thousands of years the longitudinal profile response to the lake level fall was downstream lengthening onto the exposed former lake bed. Most of the incision (~ 40 m) occurred later, when the lake level reached the top of the Amazyahu fault escarpment and continued to drop. The incision was a relatively short episode at about 17 ka and cut through this escarpment almost to its base. The fast incision, its timing, and the profiles of the incising channels indicate that the escarpment was an underwater feature and was not formed after the lake retreated. This fairly simple scenario of regressive lake level fall


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    Full Text Available Introduction: Hyperthrophic scar and keloid is a big problem after many operation. Hypertrophic scar depended on many factor one of them is Incision. Method: This is a randomized clinical trial and sequential sampling in Alzahra hospital and Kashani hospital. we selected two groups, one group we used S shape incision and observed group linear incision. Age was between 10-30 years and dermatological problems and cigaret smoking was Negative in two groups perforated and secondly skin closure was excluded in our study. patient divided in two group each group was twenty and fllowed for one year. Patients satisfaction and skin collor normality and itchiny was evaluated in two groups. Results: Appearance of scar was different in collor much and shape. Normality for collor of incision in s shape groups were 68.4% but in linar incision was 31.6% (Pvalue= 0.026 with statically meaningful. Mean of scar width: In 5-shape =1.33+0.49mm in Linear shape = 2.23+0.92. P = 0.001. Prevalence of itching was same in both groups. Discussion: patients overall satisfaction and itching were the same for both groups. skin color normality was 68.4% in 5 shape incision groups versus 31.6% in linear incision groups which has been shown to be statistically meaningful using chi-square test so it seems reasonable to conclude that calor mathing is more favorable in 5 shape incisions rather than linear incision. Mean of scare width in licear incision group was 2.23+0.92 mm versus 1.32+0.49 mm in 5 shape incision group. this difference is also statistically meaningful using T test. 50 it can be concluded that using 5 shape incision is better because post operative scar is smaller and exposure is like linear incision.

  20. A two-incision approach: promises and pitfalls. (United States)

    Rosenberg, Aaron G


    Is this an optimal procedure? Clearly, it is not for every patient, but it does serve patients who can benefit from rapid recovery as well as those patients truly interested in minimizing their down time. It also is clearly not for the occasional total hip surgeon. It is a technique that brings to the patient the maximum potential for speed of recovery. However, it is important to stress again that the surgical approach is just one factor facilitating the recovery curve. While the benefits are real, their importance must be weighed by both surgeon and patient relative to the risks. The risks are not insignificant, but generally decrease with time and experience. As opposed to several smaller incision modifications of routine approaches to THA, the two-incision approach does require a separate and distinctively different skill set, including alternative methods to make up for the lack of standard visualization and careful attention to details such as incision placement and location of the starting point in the intramedullary canal. However, in the rest of the medical world, that is what minimally invasive surgery is about.

  1. Martian fluvial conglomerates at gale crater

    NARCIS (Netherlands)

    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 III, J.F.; Farmer, J.D.; Sullivan, R.; Van Beek, T.; Blaney, D.L.; Pariser, O.; Deen, R.G.; MSL Science Team, the


    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 fluvia

  2. A Field Exercise in Fluvial Sediment Transport. (United States)

    Tharp, Thomas M.


    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…

  3. On the origin of crevasse-splay amalgamation in the Huesca fluvial fan (Ebro Basin, Spain): Implications for connectivity in low net-to-gross fluvial deposits (United States)

    van Toorenenburg, K. A.; Donselaar, M. E.; Noordijk, N. A.; Weltje, G. J.


    Floodplain deposits are abundant in low-gradient dryland river systems, but their contribution to connected reservoir volumes has not yet been fully acknowledged due to their poor detectability with typical wireline log suites and relatively-lower reservoir quality. This study presents an analysis of stacked crevasse splays in the distal part of the Miocene Huesca fluvial fan (Ebro Basin, Spain). Vertical stacking of crevasse splays implies local aggradation of the active channel belt. Lateral amalgamation of crevasse splays created an elevated rim around their feeder channel, raising its bankfull height. Subsequent crevasse splays were deposited on top of their predecessors, creating sand-on-sand contact through incision and further raising the active channel belt. This process of channel-belt super-elevation repeated until an upstream avulsion occurred. Amalgamated crevasse splays constitute connected reservoir volumes up to 107 m3. Despite their lower reservoir quality, they effectively connect channel deposits in low net-to-gross fluvial stratigraphy, and hence, their contribution to producible volumes should be considered. Unswept intervals of amalgamated crevasse splays may constitute a secondary source of natural gas. Their interval thickness can serve as a proxy for feeder-channel dimensions, which can in turn be used to estimate the degree of stratigraphic connectivity.

  4. Papilla base incision: a new approach to recession-free healing of the interdental papilla after endodontic surgery. (United States)

    Velvart, P


    The purpose of the present study was to describe and evaluate a new incision technique: the papilla base incision. Twenty healthy patients referred for surgical treatment of persisting apical periodontitis, who were free of periodontal disease and had intact interdental papillae were included in the study. The preoperative papilla height was recorded by measuring the distance between the contact point and the most coronal point of the papilla. The papilla base flap, consisting of the papilla base incision and two releasing incisions, was used to expose the bone. The papilla base incision consisted of a shallow first incision at the base of the papilla and a second incision directed to the crestal bone, creating a split thickness flap in the area of the papilla base. Further apically a full thickness flap was raised. Following standard root-end resection and filling, flap closure was achieved with microsurgical sutures. The papilla base incision was sutured with 2-3 interrupted sutures, which were removed 3-5 days after the surgery. The experimental sites were evaluated at the conclusion of the surgery, at suture removal and after 1 month, and compared to the preoperative findings. The healing pattern, complications and postoperative recession were recorded. The experimental sites were observed with a x 3 magnification and graded as to whether a visible scar resulting from the incision could be detected. Twenty experimental sites were analysed. Complete closure of the wound was achieved in all cases after surgery. Except for four patients with delayed healing at suture removal, all other patients displayed rapid healing. No noticeable space was created beneath the contact point area. The change in distance between the reference point and the most coronal point of the papilla comparing the preoperative and the one-month postoperative situation was 0.05 +/- 0.39 mm. The probing depth remained within normal limits. One month postoperatively, observation of the incision

  5. Single Incision Laparoscopic Splenectomy: Our First Experiences

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    Umut Barbaros


    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.

  6. Single-incision total laparoscopic hysterectomy

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    Sinha Rakesh


    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.

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

    Institute of Scientific and Technical Information of China (English)

    Xin-Lei Xia; Hong-Li Wang; Fei-Zhou Lyu; Li-Xun Wang; Xiao-Sheng Ma; Jian-Yuan Jiang


    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.

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

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    Xin-Lei Xia


    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.

  9. 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.

  10. Relaxing incision for control of postoperative astigmatism following keratoplasty. (United States)

    Troutman, R C; Swinger, C


    A new technique has been presented which provides a second surgical approach to correct excessive residual astigmatism following keratoplasty. The relaxing incision procedure has advantages over wedge resection in that it can be performed at the slit lamp, it gives no initial overcorrection, and it has a much shorter postoperative course while giving rapid results without suturing. Since this technique does not appear to produce significant hyperopia and may produce a tendency toward myopia, the corneal surgeon would thus have alternative techniques from which to choose, depending, in part, on the spherical component of the refraction.

  11. A case of endophthalmitis associated with limbal relaxing incision

    Directory of Open Access Journals (Sweden)

    Aravind Haripriya


    Full Text Available Limbal relaxing incisions (LRIs are considered a relatively safe procedure with rapid stabilization and absence of infectious complications. Do we need to readdress this last impression? We report a case of nocardia endophthalmitis associated with an exudate at the site of an LRI in a patient who underwent routine cataract surgery. This case, to the best of our knowledge, is the first report of its kind, stressing the need for a cautious approach to the adoption of this method of astigmatic correction.

  12. Tectonic and lithological controls on fluvial landscape development in central-eastern Portugal: Insights from long profile tributary stream analyses (United States)

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


    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

  13. Modeling fluvial erosion on regional to continental scales (United States)

    Howard, Alan D.; Dietrich, William E.; Seidl, Michele A.


    The fluvial system is a major concern in modeling landform evolution in response to tectonic deformation. Three stream bed types (bedrock, coarse-bed alluvial, and fine-bed alluvial) differ in factors controlling their occurrence and evolution and in appropriate modeling approaches. Spatial and temporal transitions among bed types occur in response to changes in sediment characteristics and tectonic deformation. Erosion in bedrock channels depends upon the ability to scour or pluck bed material; this detachment capacity is often a power function of drainage area and gradient. Exposure of bedrock in channel beds, due to rapid downcutting or resistant rock, slows the response of headwater catchments to downstream baselevel changes. Sediment routing through alluvial channels must account for supply from slope erosion, transport rates, abrasion, and sorting. In regional landform modeling, implicit rate laws must be developed for sediment production from erosion of sub-grid-scale slopes and small channels.

  14. Active tectonics coupled to fluvial erosion in the NW Himalaya (United States)

    Vannay, J.-C.; Grasemann, B.; Rahn, M.; Frank, W.; Carter, A.


    Both syntaxial extremities of the Himalaya show a spatial correlation between active exhumation of deep crustal rocks and the presence of powerful rivers, the Indus and the Tsangpo-Brahmaputra, cutting across the range two of the deepest gorges on Earth. These features strongly suggests that vigorous fluvial erosion can locally enhance isostatic and tectonic uplift, which in turn contributes to heat advection and weakening of the crust, as well as to maintain steep topographic gradients [Zeitler et al., 2001]. In order to test this positive feedback model, we combined structural and geochronological data to constrain the tectono-thermal evolution along the Sutlej (NW India), the third largest river cross-cutting entirely the Himalaya. The Himalayan crystalline core zone exposed along the Sutlej Valley is composed of two gneiss sheets, that were successively underthrusted and tectonically extruded as a consequence of the foreland-directed propagation of deformation in the Indian plate margin. During Early to Middle Miocene, combined thrusting along the Main Central Thrust (MCT) and extension along the Sangla Detachment induced the rapid exhumation and cooling of the amphibolite facies to migmatitic High Himalayan Crystalline Sequence [Vannay &Grasemann, 2001]. Underthrusting beneath the MCT led to the creation of the amphibolite facies Lesser Himalayan Crystalline Sequence (LHCS). The LHCS cooled rapidly from Late Miocene to Pleistocene, as a consequence of tectonic extrusion controlled by thrusting along the Munsiari Thrust, and extension in the MCT hanging wall. This phase is still active, as indicated by: (1) cooling rates in excess of 100^oC/Myr during the past ˜3 Myr in the LHCS; (2) Holocene neo-tectonic activity; (3) present-day hydrothermal activity testifying to elevated near-surface geothermal gradients; and (4) seismic activity along the Munsiari Thrust. Modelling of fluvial erosion in the Himalaya indicate that the Sutlej Valley corresponds to the main

  15. Martian fluvial conglomerates at Gale crater. (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


    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.

  16. Martian Fluvial Conglomerates at Gale Crater (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.


    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.

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

    Directory of Open Access Journals (Sweden)

    Nidhi Jauhari


    Full Text Available AIM:To determine the surgically induced astigmatism (SIA in Straight, Frown and Inverted V shape (Chevron incisions in manual small incision cataract surgery (SICS.METHODS: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.RESULTS: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.CONCLUSION:Inverted V (Chevron incision gives minimal SIA.

  18. Single incision laparoscopic colorectal resection: Our experience

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    Chinnusamy Palanivelu


    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.

  19. Sigmoid volvulus treated by mini-incision. (United States)

    Seow-En, I; Seow-Choen, F


    Definitive surgical management of sigmoid volvulus is usually via a midline laparotomy or laparoscopy. We report our experience with a series of five consecutive cases over a 10-year period. All patients had definitive surgery via a left iliac fossa mini-incision after prior decompression. For four patients, it was the first episode of sigmoid volvulus and one patient had a recurrent sigmoid volvulus after previous sigmoid colectomy. The latter patient had pan colonic megacolon diagnosed at initial surgery. All five cases were surgically treated successfully via a mini-incision on the left iliac fossa. There were no instances of recurrence at a median follow-up duration of 95 months (range 7-132 months). A left iliac fossa mini-incision is sufficient for the definitive management of non-perforated sigmoid volvulus. Larger studies are warranted to draw definitive conclusions.

  20. Single incision endoscopic surgery for lumbar hernia. (United States)

    Kawaguchi, Masahiko; Ishikawa, Norihiko; Shimizu, Satsuki; Shin, Hisato; Matsunoki, Aika; Watanabe, Go


    Single Incision Endoscopic Surgery (SIES) has emerged as a less invasive surgery among laparoscopic surgeries, and this approach for incisional hernia was reported recently. This is the first report of SIES for an incisional lumbar hernia. A 66-year-old Japanese woman was referred to our institution because of a left flank hernia that developed after left iliac crest bone harvesting. A 20-mm incision was created on the left side of the umbilicus and all three trocars (12, 5, and 5 mm) were inserted into the incision. The hernial defect was 14 × 9 cm and was repaired with intraperitoneal onlay mesh and a prosthetic graft. The postoperative course was uneventful. SIES for lumbar hernia offers a safe and effective outcome equivalent compared to laparoscopic surgery. In addition, SIES is less invasive and has a cosmetic benefit.

  1. Interaction of marine and fluvial clastic sedimentation, central Italy, Tyrrhenian coast

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    Evangelista, S.; Full, W.E.; Tortora, P.


    An integrated approach was used to study the interaction of fluvial, beach, and marine processes on sedimentation at the west-central coast of Italy along the Tyrrhenian Sea. The study area, 120 km northwest of Rome, is bounded on the north by Mt. Argentario, on the east by Pleistocene volcanics, on the south by the St. Augustine River, and on the west by the 50-mn bathymetric isopleth. The primary tools used included field work, textural analysis, high-resolution marine seismic, SEM, and Fourier shape analysis. Field work revealed incised streams, potentially relict beach ridges and lagoons, and relatively steep nearshore marine slopes in the northern portions of the study area. The result of the shape analysis performed on 56 samples was the definition of four end members. Each end member reflects a sedimentation process. Three end members were directly associated with fluvial sedimentation, and the fourth reflected marine processes. The seismic data along with the SEM analysis strongly supported the interpretation of four processes that dominate the recent sedimentation history. The sand interpreted to be associated with marine processes was found to represent the smoothest end member. SEM analysis suggests that the smoothing is not due to abrasion but to plastering associated with biologic processes (digestion.) and/or with silica precipitation associated with clay alteration at the freshwater/saltwater interface.

  2. Fluvial inheritances of the Cher River floodplain (region Centre, France) as elements of characterization of hydrological dynamics and their past evolutions (United States)

    Vayssière, Anaëlle; Castanet, Cyril; Gautier, Emmanuèle; Virmoux, Clément


    Geomorphological studies of floodplains provide relevant data about evolutions of fluvial landscape over long time-scales and allow a better understanding of palaeo-environnemental evolutions. The Cher River flows from the "Massif Central" to its junction with the Loire River in the South of the "Bassin de Paris". The long-term fluvial evolutions since the LGM of this medium-sized catchment, are not well documented. However, a first prospection revealed a high potential of fluvial archives. The aim of the present work is to provide elements to characterize past fluvial dynamics based on the analysis of inherited landforms (mainly palaeo-channels) and sedimentary bodies located in the floodplain, using hydrogeomorphological methods. Data are acquired through the analysis of DEM LiDAR, geophysical methods (electric tomography) and cores (boreholes) collected in the floodplain. The analysis of DEM LiDAR and morpho-sedimentary observations yields palaeo-hydrographical reconstructions and allows two generations of topographic and sedimentary fluvial inheritances to be identified. Most ancient fluvial landforms correspond to mounds slightly higher than the floodplain level, incised by wide and shallow palaeo-channels. A second fluvial pattern, more recent, is characterized by palaeo-meanders. Measuring the width, the amplitude and the curvature, we show that some of the palaeo-meanders are much larger, wider and more sinuous than the current meanders, showing changes in past flow regime. The analysis of the filling of palaeo-channels allows us to identify firstly the transverse and longitudinal geometry of former channels. These data help us to estimate bank-full discharge of palaeo-channels. Secondly, the morpho-sedimentary analysis highlights their post-abandonment environmental changes. Three main stratigraphic units are identified. (1) At the base, there is medium and coarse sand attributed to fluvial transport. (2) It is overlain by a layer composed of organo

  3. Fluvial Erosion and Transportation of an Impact Regolith Layer: Implications for Titan (United States)

    Moore, Jeffrey M.; Howard, Alan D.; Breton, Sylvain


    Large regions of Titan appear to be eroded cratered terrain. If this is correct, then Titan’s surface could have been characterized by a regolith hundreds of meters thick with abundant unconsolidated debris in the size range that could be fluvially transported and serving as tools for bedrock incision. We utilized a variant on our Landform Evolution Model, originally developed to understand fluvial erosion on Mars, to study this issue. We see two end-member results. Slopes covered with coarse grained material develop a drainage network that essentially becomes stabilized after a sufficient time. They become paved with gravel that can only be eroded very slowly, if at all, after some degree of erosion. Simulations with finer sediment (for example with the maximum grain size only 16 mm) the flow can transport a good bit of sediment throughout the simulation, and drainage basins are initially created, but the topography evolves into a gentle slope of parallel drainage. For gravel channel systems under high sediment transport situations, there is no downstream concavity - the channels are essentially uniform in slope so that no drainage basins form. However, for coarser sediment we are near the threshold of motion near the end of the simulation, and channel gradients decrease downstream, implying a well-developed drainage network will form. However, if boulders are intermixed with the fines (which is reasonable), upland surfaces could eventually become mantled with a pavement of coarse debris after differential removal of transportable sediment, thus limiting net erosion unless a weathering (rock-disintegrating) process occurs on Titan. Titan’s fluvial networks could have been quickly established, then become somewhat impervious to further landscape evolution even if the precipitation rates and intensities persisted for long times.

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

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    Md Shafiqul Alam


    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

  5. Single-incision laparoscopic cholecystectomy:Single institution experience and literature review

    Institute of Scientific and Technical Information of China (English)

    Yasumitsu; Hirano; Toru; Watanabe; Tsuneyuki; Uchida; Shuhei; Yoshida; Kanae; Tawaraya; Hideaki; Kato; Osamu; Hosokawa


    Single-incision laparoscopic surgery is a rapidly evolving field as a bridge between traditional laparoscopic surgery and natural orifice transluminal endoscopic surgery.We report one of the initial clinical experiences in Japan with this new technique.Four cases of gallbladder diseases were selected for this new technique.A single curved intra-umbilical 25-mm incision was made by pulling out the umbilicus.A 12-mm trocar was placed through an open approach,and the abdominal cavity was explored with a 10-mm ...

  6. Vision for a worldwide fluvial-sediment information network (United States)

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


    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.

  7. Single-Incision Laparoscopic Total Colectomy (United States)

    Ojo, Oluwatosin J.; Carne, David; Guyton, Daniel


    Background and Objectives: To present our experience with a single-incision laparoscopic total colectomy, along with a literature review of all published cases on single-incision laparoscopic total colectomy. Methods: A total of 22 cases were published between 2010 and 2011, with our patient being case 23. These procedures were performed in the United States and United Kingdom. Surgical procedures included total colectomy with end ileostomy, proctocolectomy with ileorectal anastomosis, and total proctocolectomy with ileopouch-anal anastomosis. Intraoperative and postoperative data are analyzed. Results: Twenty-two of the 23 cases were performed for benign cases including Crohns, ulcerative colitis, and familial adenomatous polyposis. One case was performed for adenocarcinoma of the cecum. The mean age was 35.3 years (range, 13 to 64), the mean body mass index was 20.1 (range, 19 to 25), mean operative time was 175.9 minutes (range, 139 to 216), mean blood loss was 95.3mL (range, 59 to 200), mean incision length was 2.61cm (range, 2 to 3). Average follow-up was 4.6 months with 2 reported complications. Conclusions: Single-incision laparoscopic total colectomy is feasible and safe in the hands of an experienced surgeon. It has been performed for both benign and malignant cases. It is comparable to the conventional multi-port laparoscopic total colectomy. PMID:22906326

  8. Influence of fluvial processes on the quaternary geologic framework of the continental shelf, North Carolina, USA (United States)

    Boss, S.K.; Hoffman, C.W.; Cooper, B.


    Digital, single-channel, high-resolution seismic reflection profiles were acquired from the insular continental shelf of North Carolina, USA along a data grid extending from Oregon Inlet northward 48 km to Duck, North Carolina and from the nearshore zone seaward approximately 28 km (total surveyed area= 1334 km2). These data were processed and interpreted to delineate principal reflecting horizons and develop a three-dimensional seismic stratigraphic framework for the continental shelf that was compared to stratigraphic data from the shoreward back-barrier (estuarine) and barrier island system. Six principal reflecting horizons (designated R0 through R5) were present within the upper 60 m of the shelf stratigraphic succession. Three-dimensional mapping of reflector R1 demonstrated its origin from fluvial incision of the continental shelf during an episode (or episodes) of lowered sea-level. Fluvial processes during development of reflector R1 were responsible for extensive reworking and re-deposition of sediment throughout most of the northern half of the study area. Five seismic stratigraphic units (designated S1 through S5) were tentatively correlated with depositional sequences previously identified from the North Carolina back-barrier (estuarine) and barrier island system. These five stratigraphic units span the Quaternary Period (S1 = early Holocene; S2 = 51-78 ka; S3 = 330-530 ka; S4 = 1.1-1.8 Ma; S5 = earliest Pleistocene). Unit S1 is composed of fine-grained fluvial/estuarine sediment that back-filled incised streams during early Holocene sea-level rise. The four other stratigraphic units (S2-S5) display tabular depositional geometries, low total relief, and thicken toward the east-southeast as their basal reflectors dip gently between 0.41 m km-1 (0.02??) and 0.54 m km-1 (0.03??). Knowledge of the three-dimensional subsurface stratigraphic architecture of the continental shelf enhances understanding of the development of shelf depositional successions and

  9. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco;


    (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial...... the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks, and resulting in higher ecosystem productivity and CO2 outgassing.......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...

  10. Radiological findings after endoscopic incision of ureterocele

    Energy Technology Data Exchange (ETDEWEB)

    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 [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Cheon, Jung Eun [Chungmu General Hospital, Chungmu (Korea, Republic of); Seok, Eul Hye [Seran General Hospital, Seoul (Korea, Republic of); Cha, Joo Hee [Green General Hospital, Seoul(Korea, Republic of); Choi, Guk Myung [Halla General Hospital, Cheju (Korea, Republic of)


    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.

  11. Canyon incision, volcanic fill, and re-incision rates in southwest Peru: proxies for quantifying uplift in the Central Andes (United States)

    Thouret, Jean-Claude; Gunnell, Yanni; de La Rupelle, Aude


    Using zircon and apatite fission tracks and apatite (U-Th)/He to constrain 26 rock cooling histories of Cretaceous diorites and 40Ar-39Ar to date 45 Neogene ignimbrites and lavas, we have estimated incision and topographic uplift rates of the Western Cordillera in southwest Peru. Rock cooling patterns confirm that continental denudation declined rapidly during the early Cenozoic. Topographic paleoelevations provided by 24.5 Ma forearc marine sediments now occurring at 1.8 km a.s.l. indicate that the Andean orogenic plateau did not begin to rise before Miocene time. A suite of marker horizons consisting of Huaylillas ignimbrite (14.3-12.7 Ma) on the plateau, and of Sencca ignimbrite (3.8 Ma) and Barroso lavas (2.27 Ma) near the Rio Cotahuasi and Rio Ocoña valley floors, respectively, have helped to bracket accelerated uplift between 13 Ma and 3.8-2.27 Ma. In-canyon (U-Th)/He bedrock cooling ages decrease upstream from ~13 Ma to 2-4 Ma, implying that uplift-driven valley incision began after 14 Ma and that downcutting was neither steady nor uniform along the 209 km-long canyon system. Whereas ~9 Ma Caraveli ignimbrites filled broad, shallow valleys, V-shaped downcutting occurred after 9-6 Ma. Argon-dated in-canyon lava flows and ignimbrites reveal three pulses of bedrock incision: 8.8-5.8 Ma, 5.8-3.6 Ma, 3.6-1.36 Ma, followed by post-1.36 Ma re-incision into unconsolidated valley fill. Accordingly, ample variations belie the 14 Myr-averaged incision rate of 170 m Myr-1: 130-190 m Myr-1 between 13 and 9 Ma, rising to 250-400 m/Myr-1 between 9 and 3.8 Ma and to >1000 m Myr-1 of reincision after 1.36 Ma. Rapid bedrock incision ended before 3.76 Ma in the upper, and before 2.27 Ma in the lower canyon reaches. The 3.76 to 1.36 Ma pyroclastic and mass-flow deposits filled the valley to ~75% and ~60% of its height in its upper and lower reaches, respectively. Post-1.36 Ma re-incision removed 75% of these deposits, thus exhuming most of the bedrock paleocanyon. The upper

  12. Longitudinal incision in surgical release of De Quervain disease. (United States)

    Gundes, Hakan; Tosun, Bilgehan


    The objective of this paper is to contrast the use of a longitudinal incision in surgical decompression of De Quervain disease with a transverse incision. The advantages are ease in recognition of compartment variations and superficial branches of radial nerve and prevention of palmar tendon subluxation by permitting a more dorsal release of the compartment sheath. Since 2002, we have used a longitudinal skin incision instead of the classic transverse incision to release the first dorsal compartment.

  13. Fluvial processes on Mars: Erosion and sedimentation (United States)

    Squyres, Steven W.


    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.

  14. Surficial geological tools in fluvial geomorphology (United States)

    Jacobson, Robert B.; O'connor, James; Oguchi, Takashi


    Environmental scientists are increasingly asked how rivers and streams have been altered by past environmental stresses, whether rivers are subject to physical or chemical hazards, how they can be restored and how they will respond to future environmental changes. These questions present substantive challenges to the discipline of fluvial geomorphology as they require a long-term understanding of river-system dynamics. Complex and non-linear responses of rivers to environmental stresses indicate that synoptic or short-term historical views of rivers will often give an incomplete understanding. Fluvial geomorphologists can address questions involving complex river behaviours by drawing from a tool box that includes the principles and methods of geology applied to the surficial geological record. A central concept in Earth Sciences holds that ‘the present is the key to the past’ (Hutton 1788, cited in Chorley et al. 1964), that is, understanding of current processes permits the interpretation of past deposits. Similarly, an understanding of the past can be key to predicting the future. A river’s depositional history can be indicative of trends or episodic behaviours that can be attributed to particular environmental stresses or forcings. Its history may indicate the role of low-frequency events such as floods or landslides in structuring a river and its floodplain or a river’s depositional history can provide an understanding of its natural characteristics to serve as a reference condition for assessments and restoration. However, the surficial geological record contained in river deposits is incomplete and biased and it presents numerous challenges of interpretation. The stratigraphic record in general has been characterized as ‘ … a lot of holes tied together with sediment’ (Ager 1993). Yet this record is critical in the development of integrated understanding of fluvial geomorphology because it provides information that is not available from other

  15. The Influence of Inherited Topography and/or Tectonics on Paleo-channel Systems and Incised Valleys Offshore of South Carolina (United States)

    Long, A. M.; Hill, J. C.


    The Quaternary paleo-channel and incised valley systems of the Southeastern United States have been well documented onshore; however, few studies have focused on the positions and fill histories of these systems on the continental shelf. The effects of inherited topography can be studied through the integration of seismo-acoustic and core data. Existing offshore datasets have been used to document underlying structural and stratigraphic fabrics deeper than the Quaternary in the sedimentary record. By integrating these results with the published tectonic setting and onshore interpretations, some of the controls on paleo-channel/incised valley positions can be inferred. Preliminary results suggest the stress caused by the uplift along the Cape Fear Arch has been accommodated by shallow folding and reactivation of deeper structures in the South Carolina offshore province. The resultant topography may have dictated both the position and geometry of the fluvial incisions across the shelf. This in turn influences the accommodation space available to be filled in as sea level fluctuates. The depositional facies within the paleo-channel and incised valley range from single, uninterrupted fill to complex and repeated scour and fill with at least four different episodes of erosion and deposition. The observations and interpretations proposed here are the first steps in unraveling the complex interplay between sea level, climate, and tectonic changes on the morphology and stratigraphy of incised valleys and paleo-channels observed offshore of South Carolina.

  16. Comparison of three incisions to repair complete unilateral cleft lip.

    NARCIS (Netherlands)

    Reddy, S.; Reddy, R.R.; Bronkhorst, E.M.; Prasad, R.; Kuijpers-Jagtman, A.M.; Berge, S.J.


    BACKGROUND: The incision design for correcting a unilateral cleft lip is important because all subsequent stages of surgery depend on the access and maneuverability of the incision. This prospective cohort study compares the aesthetic and functional outcomes of three different skin incisions for pri

  17. Comparison of three incisions to repair complete unilateral cleft lip.

    NARCIS (Netherlands)

    Reddy, S.; Reddy, R.R.; Bronkhorst, E.M.; Prasad, R.; Kuijpers-Jagtman, A.M.; Berge, S.J.


    BACKGROUND: The incision design for correcting a unilateral cleft lip is important because all subsequent stages of surgery depend on the access and maneuverability of the incision. This prospective cohort study compares the aesthetic and functional outcomes of three different skin incisions for pri

  18. Differential diagnosis and management of giant fibroadenoma: comparing excision with reduction mammoplasty incision and excision with inframammary incision. (United States)

    Ugburo, Andrew O; Olajide, Thomas O; Fadeyibi, Idowu O; Mofikoya, Bolaji O; Lawal, Abdulrazzaq O; Osinowo, Adedapo O


    Giant fibroadenoma (GFA) may present with breast asymmetry and can be excised with an inframammary incision (IFI) or reduction mammoplasty incision (RMI). This study investigated the clinical presentation and compared excision with the IFI and RMI. All patients with benign breast tumours greater than 5 cm underwent core needle biopsy and a histopathological diagnosis. All confirmed GFA had their clinical details documented and randomised into two groups for excision with an IFI or RMI. Twenty-two patients were studied. The age range was 12-46 years, mean 21.18 ± 2.22 years. The patients were divided into two groups: a juvenile group (n = 16) (73%) aged 12-18 years, mean age 14.06 ± 0.42 years, and a perimenopausal group (n = 5) aged 28-46 years. The juvenile group showed cyclic increases in breast size monthly with menstruation while the perimenopausal showed an initial slow growth of 6-24 months followed by a rapid growth. Fifteen patients (68%) had excision biopsy with IMI and seven patients with RMI. Seven of the patients treated with IFI had minimal preoperative asymmetry and satisfactory aesthetic outcome. Among the patients with severe preoperative asymmetry treated with IFI (n = 8) and RMI (n = 7), those treated with IFI had persistent postoperative skin redundancy and asymmetry, which was not found in those treated with RMI. In conclusion, for patients with significant asymmetry, excision with the IFI was associated with persistent asymmetry while excision with RMI was associated with restoration of symmetry.

  19. Controls on aggradation and incision in the NE Negev, Israel, since the middle Pleistocene (United States)

    Matmon, A.; Elfassi, S.; Hidy, A.; Geller, Y.; Porat, N.


    We investigated the mid-Pleistocene to recent aggradation-incision pattern of two drainage systems (Nahal Peres and Nahal Tahmas) in the hyperarid north eastern Negev desert, southern Israel. Although these drainage systems drain into the tectonically active Dead Sea basin, lake level fluctuations cannot account for the aggradation-incision pattern as bedrock knickpoints disconnect the investigated parts of these drainage systems from base level influence. We applied geomorphic mapping, soil stratigraphy, optically stimulated luminescence (OSL) and cosmogenic (in situ 10Be) exposure dating to reconstruct cycles of aggradation and incision of alluvial terraces and to study their temporal association with regional periods of humidity and aridity and global glacial-interglacial cycles. The spatial and temporal relationships between the alluvial units suggest changes in the drainage system behavior since the middle Pleistocene, and show a pattern in which prolonged periods of sediment aggradation alternated with short periods of rapid and intense degradation through erosion and incision into sediment and bedrock. We obtain ages for several Pleistocene-Holocene periods of incision: ~ 1.1 Ma, ~ 300 ka, ~ 120 ka, ~ 20 ka, ~ 12 ka and ~ 2 ka. Although broadly synchronous, the Nahal Peres and Nahal Tahmas systems exhibit temporal differences in aggradation and incision. Hyperarid conditions have persisted in the region at least since the middle Pleistocene, as evidenced by gypsic-salic soils that ubiquitously cap the investigated alluvial terraces. This observation is consistent with other observations throughout the Negev indicating prolonged aridity. Thus, alternation between sediment aggradation and degradation cannot be correlated in a simple and straightforward way to climatic changes. We explain the temporal differences in aggradation and incision between Nahal Peres and Nahal Tahmas as resulting from the differences in stream gradient, basin hypsometry, and drainage

  20. Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California (United States)

    Schumann, R. Randall; Pigati, Jeffery S.; McGeehin, John P.


    Santa Rosa Island (SRI) is one of four east-west aligned islands forming the northern Channel Islands chain, and one of the five islands in Channel Islands National Park, California, USA. The island setting provides an unparalleled environment in which to record the response of fluvial systems to major changes of sea level. Many of the larger streams on the island occupy broad valleys that have been filled with alluvium and later incised to form steep- to vertical-walled arroyos, leaving a relict floodplain as much as 12–14 m above the present channel. The period of falling sea level between the end of the last interglacial highstand at ~ 80 ka and the last glacial lowstand at ~ 21 ka was marked by erosion and incision in the uplands and by deposition of alluvial sediment on the exposed marine shelf. Sea level rose relatively rapidly following the last glacial lowstand of − 106 m, triggering a shift from an erosional to a depositional sedimentary regime. Accumulation of sediment occurred first through vertical and lateral accretion in broad, shallow channels on the shelf. Channel avulsion and delta sedimentation produced widespread deposition, creating lobes or wedges of sediment distributed across relatively large areas of the shelf during the latest Pleistocene. Backfilling of valleys onshore (landward of present sea level) appears to have progressed in a more orderly and predictable fashion throughout the Holocene primarily because the streams were confined to their valleys. Vertical aggradation locally reduced stream gradients, causing frequent overbank flooding and lateral channel shift by meandering and/or avulsion. Local channel gradient and morphology, short-term climate variations, and intrinsic controls also affected the timing and magnitudes of these cut, fill, and flood events, and are reflected in the thickness and spacing of the episodic alluvial sequences. Floodplain aggradation within the valleys continued until at least 500 years ago

  1. Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California (United States)

    Schumann, R. Randall; Pigati, Jeffrey S.; McGeehin, John P.


    Santa Rosa Island (SRI) is one of four east-west aligned islands forming the northern Channel Islands chain, and one of the five islands in Channel Islands National Park, California, USA. The island setting provides an unparalleled environment in which to record the response of fluvial systems to major changes of sea level. Many of the larger streams on the island occupy broad valleys that have been filled with alluvium and later incised to form steep- to vertical-walled arroyos, leaving a relict floodplain as much as 12-14 m above the present channel. The period of falling sea level between the end of the last interglacial highstand at ~ 80 ka and the last glacial lowstand at ~ 21 ka was marked by erosion and incision in the uplands and by deposition of alluvial sediment on the exposed marine shelf. Sea level rose relatively rapidly following the last glacial lowstand of - 106 m, triggering a shift from an erosional to a depositional sedimentary regime. Accumulation of sediment occurred first through vertical and lateral accretion in broad, shallow channels on the shelf. Channel avulsion and delta sedimentation produced widespread deposition, creating lobes or wedges of sediment distributed across relatively large areas of the shelf during the latest Pleistocene. Backfilling of valleys onshore (landward of present sea level) appears to have progressed in a more orderly and predictable fashion throughout the Holocene primarily because the streams were confined to their valleys. Vertical aggradation locally reduced stream gradients, causing frequent overbank flooding and lateral channel shift by meandering and/or avulsion. Local channel gradient and morphology, short-term climate variations, and intrinsic controls also affected the timing and magnitudes of these cut, fill, and flood events, and are reflected in the thickness and spacing of the episodic alluvial sequences. Floodplain aggradation within the valleys continued until at least 500 years ago, followed by

  2. Neck incision planning for total laryngectomy: A finite element analysis. (United States)

    Feng, Allen L; Clark, James H; Agrawal, Nishant; Moussa, Walied; Richmon, Jeremy D


    Post-operative complications can be attributed to technical aspects of surgery, yet no studies have investigated the mechanics behind commonly used incisions for total laryngopharyngectomies (TLP). This procedure, seen in head and neck cancer patients, necessitates free tissue transfer to construct a neo-pharynx, creating an inherently greater risk of complications. We sought to investigate the impact of neck incision location on these post-operative complications for TLP using finite element analysis (FEA). A nonlinear hyperelastic 2-D finite element model was used to evaluate the stress and strain along the incision line of two separate neck incision models commonly used for TLP: low-neck apron (LNA) incisions that incorporate the patient׳s tracheostoma and mid-neck apron (MNA) incisions that do not communicate with the tracheostoma. A constant displacement was applied to the incision to simulate normal neck extension experienced during the post-operative phase. Each neck incision was also modeled at varying strain energy densities to simulate various stages of wound healing. For a constant displacement of 40mm, the principal von Mises stress of the LNA incision varied between 5.87 and 6.41MPa, depending on the hyperelastic properties of the healing incision. This stress was concentrated at the junction of the incision and the fixed tracheostomal edge. The MNA model demonstrated a principal von Mises stress that varied between 0.558 and 0.711MPa and was concentrated along the midline of the neck incision. MNA incisions for TL patients result in principal von Mises stresses which are up to 11 times lower than those seen in LNA incisions. These results coincided with clinical observations from a concurrent study that showed a decrease in rate of wound dehiscence for patients undergoing TLP with an MNA incision.

  3. Climate-driven sediment aggradation and incision since the late Pleistocene in the NW Himalaya, India (United States)

    Dey, Saptarshi; Thiede, Rasmus C.; Schildgen, Taylor F.; Wittmann, Hella; Bookhagen, Bodo; Scherler, Dirk; Jain, Vikrant; Strecker, Manfred R.


    Deciphering the response of sediment routing systems to climatic forcing is fundamental for understanding the impacts of climate change on landscape evolution. In the Kangra Basin (northwest Sub-Himalaya, India), upper Pleistocene to Holocene alluvial fills and fluvial terraces record periodic fluctuations of sediment supply and transport capacity on timescales of 103 to 105 yr. To evaluate the potential influence of climate change on these fluctuations, we compare the timing of aggradation and incision phases recorded within remnant alluvial fans and terraces with climate archives. New surface-exposure dating of six terrace levels with in-situ cosmogenic 10Be indicates the onset of incision phases. Two terrace surfaces from the highest level (T1) sculpted into the oldest preserved alluvial fan (AF1) date back to 53.4 ± 3.2 ka and 43.0 ± 2.7 ka (1σ). T2 surfaces sculpted into the remnants of AF1 have exposure ages of 18.6 ± 1.2 ka and 15.3 ± 0.9 ka, while terraces sculpted into the upper Pleistocene-Holocene fan (AF2) provide ages of 9.3 ± 0.4 ka (T3), 7.1 ± 0.4 ka (T4), 5.2 ± 0.4 ka (T5) and 3.6 ± 0.2 ka (T6). Together with previously published OSL ages yielding the timing of aggradation, we find a correlation between variations in sediment transport with oxygen-isotope records from regions affected by the Indian Summer Monsoon. During periods of increased monsoon intensity and post-Last Glacial Maximum glacial retreat, aggradation occurred in the Kangra Basin, likely due to high sediment flux, whereas periods of weakened monsoon intensity or lower sediment supply coincide with incision.

  4. Incisiones verticales en SARPE Vertical incisions in SARPE

    Directory of Open Access Journals (Sweden)

    J. Gonzalez Lagunas


    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.

  5. The assessment of cold hyperalgesia after an incision. (United States)

    Scherer, Moritz; Reichl, Sylvia U; Augustin, Miriam; Pogatzki-Zahn, Esther M; Zahn, Peter K


    Although cold hypersensitivity is a well-documented phenomenon in animals and humans with inflammatory and neuropathic pain, little is known about the presence of cold hyperalgesia after surgery. Therefore, we studied primary cold hyperalgesia after a surgical incision in mice. Before and after plantar incision, inflammation with complete Freund adjuvant, and spared nerve ligation, unrestrained male animals were placed on a Peltier-cooled cold plate with a surface temperature of 0 degrees C and withdrawal latencies were measured. Additionally, incision-induced cold hyperalgesia was also assessed in female animals. Furthermore, skin temperature before and after plantar incision and inflammation were assessed by using infrared thermography (Varioscan LW 3011; Infratec, Dresden, Germany). Cold hyperalgesia to a noxious cold stimulus was observed after inflammation and nerve injury but not after a surgical incision. Similar results were demonstrated for female animals after incision. Furthermore, a significant increase in skin temperature was recorded after inflammation but not after incision, indicating that a surgery evokes only minor inflammatory effects. The present data give strong evidence that a surgical incision does not cause cold hyperalgesia. Furthermore, a lack of cold hyperalgesia in unrestrained male and female mice after incision was not due to increased skin temperature after incision. Finally, we demonstrated that in contrast to a surgical incision, inflammation and nerve injury generate intense cold hyperalgesia and an increase in skin temperature, suggesting that different mechanisms are involved in surgical and inflammatory or neuropathic pain.

  6. Closed incision management with negative pressure wound therapy (CIM): biomechanics. (United States)

    Wilkes, Robert Peyton; Kilpad, Deepak V; Zhao, Yabin; Kazala, Richard; McNulty, Amy


    A novel closed incision management with negative pressure wound therapy (CIM) has been developed for convenient use with closed incisions that has the potential to be beneficial for patients at risk for postoperative complications. Incisions are typically under lateral tension. This study explored the biomechanical mechanisms by which integrity of the incisional closure is enhanced by CIM. CIM was hypothesized to affect local stresses around closed incisions in a beneficial manner. Finite element analyses (FEA) indicated that application of CIM decreased the lateral stresses ~50% around the incision and changed the direction of the stresses to a distribution that is typical of intact tissue. Bench evaluations corroborated findings that CIM significantly increased the force required to disrupt the closed incision by ~50% as compared with closure alone. In conclusion, using 2 FEAs and bench modeling, CIM was shown to reduce and normalize tissue stresses and bolster appositional forces at the incision.

  7. The use of a surgical incision management system on vascular surgery incisions: a pilot study. (United States)

    Weir, Gregory


    Health care-associated infections in hospitals, including surgical site infections, contribute significantly to morbidity as well as mortality. Surgical incision management (SIM) using negative pressure wound therapy (Prevena™ Incision Management System, Kinetic Concepts, Inc., San Antonio, TX, USA) is designed to cover and protect closed surgical incisions from external factors including infectious sources and local trauma, while negative pressure removes fluid and infectious material from the surgical incision. A prospective case-control study assessed wound complications in patients undergoing vascular bypass procedures, where both femoral areas were incised to gain access to the femoral arteries. SIM was placed on one femoral area while a standard postoperative wound dressing was placed on the contralateral femoral area. Eight patients were included in this pilot study. All of them required bilateral femoral artery access. During the follow-up period patients were monitored for wound complications. All wound complications requiring surgical intervention were considered significant. No significant wound complications occurred in wounds treated with SIM, compared with three significant complications in control wounds. These preliminary data would suggest a potential reduction in wound complications and no observed increase in haemorrhage in high-risk patients with severe co-morbidities undergoing vascular surgery.

  8. Right Kocher’s incision: a feasible and effective incision for right hemicolectomy: a retrospective study

    Directory of Open Access Journals (Sweden)

    Theodosopoulos Theodosios


    Full Text Available Abstract Background The choice of surgical incision is determined by access to the surgical field, particularly when an oncological resection is required. Special consideration is also given to other factors, such as postoperative pain and its sequelae, fewer complications in the early postoperative period and a lower occurrence of incisional hernias. The purpose of this study is to compare the right Kocher’s and the midline incision, for patients undergoing right hemicolectomy, by focusing on short- and longterm results. Methods Between 1995 and 2009, hospital records for 213 patients that had undergone a right hemicolectomy for a right- sided adenocarcinoma were retrospectively studied. 113 patients had been operated via a Kocher’s and 100 via a midline incision. Demographic details, operative data (explorative access to the peritoneal cavity, time of operation, recovery parameters (time with IV analgesic medication, time to first oral fluid intake, time to first solid meal, time to discharge, and oncological parameters (lymph node harvest, TNM stage and resection margins were analyzed. Postoperative complications were also recorded. The two groups were retrospectively well matched with respect to demographic parameters and oncological status of the tumor. Results The median length of the midline incision was slightly longer (12 vs. 10 cm, p  Conclusions The Kocher’s incision approach for right- sided colon cancer is technically feasible, safe and overall very well tolerated. It can achieve the same standards of tumor resection and surgical field accessibility as the midline approach, while reducing postoperative recovery.

  9. Clinical Use of a Drain Incision Placed Below and Bilaterial to Near Total Thyroidectomy Incision

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-guo; ZHAO Qi-kang; CHEN Rong-rui; LI Ming-qiang; WANG Jian-jun


    Objective:To design a new draining method for near total thyroidectomy at the lower two sides of the neck.Methods:Near total thyroidectomies in 63 cases were performed with new drain incisions at the lower two sides of the neck between December 1998 and July 2004. Results:All the draining operative procedures were performed smoothly,and all produced cosmetic scars were effective. The mean amount drained was 38 ml(minimum 10 ml,maximum 120 ml)and no patient developed wound infection. Conclusion:The drain incision for near total thyroidectomy placed at the lower sides of the neck results in a cosmetic scar which is easily covered by the collar,and was safe and efiective.We thereby recommend the use of this drain incision for near total thyroidectomy.


    Institute of Scientific and Technical Information of China (English)

    刘宝国; 王斌; 张乃嵩


    Objective: To design a new draining method for hemithyroidectomy at the lower side of the neck. Methods:Hemithyroidectomies of 235 cases were performed with the new drain incision at the lower side of the neck between December 1998 and July 2003. Results: All the draining operative procedures were performed smoothly, and produced a cosmeticulous scar. The mean amount drained was 20 ml (minimum 5 ml, maximum 80 ml) and no patients developed wound infection. Conclusion: The drain incision for hemithyroidectomy placed at the lower side of the neck results in a cosmeticulous scar which is easily covered by the collar and was safe and effective. We thereby recommend the use of this drain incision for hemithyroidectomy.

  11. A Multi-Scale Assessment of How Topoclimate-Driven Ecohydrologic Feedbacks Impact Drainage Erosion, Incision and Expansion (United States)

    Poulos, M. J.; Pierce, J. L.; McNamara, J. P.; Flores, A. N.; Benner, S. G.


    Water storage and partitioning at pedon and hillslope scales ultimately dictates catchment-scale runoff production and associated fluvial erosion and drainage development. Consequently, within a given catchment, local topographic variability of aspect, elevation, and slope, appears to drive microclimatic and ecohydrologic feedbacks that alter the amount of water partitioned for ecosystem use and runoff production, which culminates in differences in drainage erosion, incision and expansion at catchment scales. This work assesses aspect-related variability in hillslope and drainage forms in the field and by geomorphometric analyses of 1 meter resolution digital elevation models derived from airborne LiDAR data. Drainage characteristics are compared to erosion amounts and rates estimated by coupling high-resolution alluvial fan geometries with radiocarbon dating of charcoal contained within fan deposits. Soil profile water balance data stratified across aspects and elevations within the Dry Creek Experimental Watershed, near Boise, Idaho, are upscaled to catchments in order to explore how topoclimatic variability affects catchment-scale soil water storage, runoff production, and drainage erosion, incision, and expansion. The analyses reveal and explain systematic differences in drainage evolution with aspect. Reduced insolation on northern aspects appears to promote the growth of denser and different vegetation (e.g. coniferous forest vs. sagebrush steppe), which is associated with thicker, finer-grained, organic-rich soils mantling hillslopes that appear stable at steeper slope angles. Differences in soil properties on northern aspects allow them to retain more water, which is lost by evapotranspiration, resulting in less runoff and decreased drainage erosion, incision and expansion. The outlets of catchments incised into north-facing slopes do not appear to be active under modern conditions, but exhibit inactive alluvial fans composed of charcoal-rich debris

  12. Morphology of the last subaerial unconformity on a shelf: insights into transgressive ravinement and incised valley occurrence in the Gulf of Cádiz (United States)

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


    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.

  13. Minimum-incision metatarsal ray resection: an observational case series. (United States)

    Roukis, Thomas S


    This report describes the results of 17 metatarsal ray resections performed through a minimal incision in 13 consecutive patients. Each patient underwent minimum-incision metatarsal ray resection for either definitive treatment or as the index incision and drainage procedure followed by transmetatarsal amputation. There were 10 male and 3 female patients with a mean age of 68.8 +/- 8.5 years (range, 59-83 years). Twelve patients had diabetes mellitus and 7 had critical limb ischemia. There were 11 right feet and 6 left feet involved, and 3 second, 3 third, 3 fourth, and 8 fifth minimum-incision metatarsal ray resections performed. Direct primary-incision closure was performed 7 times (1 with adjacent percutaneous metatarsal osteotomy), delayed primary closure was performed 4 times (1 with external fixation), and conversion to a transmetatarsal amputation was performed 2 times. Fourteen of 17 minimum-incision metatarsal ray resections were deemed successful. Two failures occurred when skin necrosis developed from excessive tension along the incision line requiring conversion to a transmetatarsal amputation, and the other occurred in a patient with unreconstructed critical limb ischemia who underwent multiple repeated incision and drainage procedures and vascular bypass with ultimate healing via secondary intent. When properly performed in patients with adequate vascular inflow, minimum-incision metatarsal ray resection as the definitive procedure or in conjunction with an incision and drainage for unsalvageable toe infection or gangrene represents a safe, simple, useful technique.

  14. 100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina (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.


    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

  15. A single incision transaxillary thoracoscopic sympathectomy

    Directory of Open Access Journals (Sweden)

    Marić Nebojša


    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

  16. Small-incision lenticule extraction (SMILE)

    DEFF Research Database (Denmark)

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


    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...... 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...

  17. Transanal polypectomy using single incision laparoscopic instruments. (United States)

    Dardamanis, Dimitrios; Theodorou, Dimitrios; Theodoropoulos, George; Larentzakis, Andreas; Natoudi, Maria; Doulami, Georgia; Zoumpouli, Christina; Markogiannakis, Haridimos; Katsaragakis, Stylianos; Zografos, George C


    Transanal excision of rectal polyps with laparoscopic instrumentation and a single incision laparoscopic port is a novel technique that uses technology originally developed for abdominal procedures from the natural orifice of the rectum. Transanal endoscopic microsurgery (TEM) is a well established surgical approach for certain benign or early malignant lesions of the rectum, under specific indications. Our technique is a hybrid technique of transanal surgery, a reasonable method for polyp resection without the need of the sophisticated and expensive instrumentation of TEM which can be applied whenever endoscopic or conventional transanal surgical removal is not feasible.

  18. Excursions in fluvial (dis)continuity (United States)

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


    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

  19. [Incisions for biaxial and coaxial microincision cataract surgery]. (United States)

    Müller, M; Kohnen, T


    Microincision cataract surgery (MICS) represents a new level in the development of cataract surgery. Phacoemulsification with intraocular lens (IOL) implantation via incisions of phaco tip (C-MICS), or by the biaxial approach, with separation of the phaco tip and irrigation (B-MICS). Compared with standard small-incision cataract surgery, the advantages of MICS are less corneal astigmatism and fewer corneal surface irregularities, with favorable implications for visual quality and early rehabilitation. In the effort toward smaller incisions, special interest should be given to wound integrity, especially regarding the risk of endophthalmitis. With limited corneal elastic capacity, irreversible expansion of the incision with tissue laceration may occur. Smaller incisions are superior only if they cause less trauma. This requires an optimized relationship between incision size and manipulation during IOL implantation as well as attention to safety issues. MICS offers a platform for new benchmarks in phacoemulsification.

  20. Vertical compared with transverse incisions in abdominal surgery

    DEFF Research Database (Denmark)

    Grantcharov, T P; Rosenberg, J


    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......, 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.......0001), and regarding late incisional hernia the pooled odds ratio was 1.68 (95% confidence interval 1.10 to 2.57. p = 0.02). CONCLUSIONS: Transverse incisions in abdominal surgery are based on better anatomical and physiological principles. They should be recommended, as the early postoperative period is associated...

  1. 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. ... Sediment source studies involving a simple mixing model was undertaken in the ... For bank erosion, river channel bank materials were sampled.

  2. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco


    DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM...

  3. Fluvial-Marine Interactions, Maine (BUYNEVICH01 shapefile) (United States)

    U.S. Geological Survey, Department of the Interior — Grab samples and cores were collected as part of a study of the fluvial-marine interaction in the system comprised by the Kennebec River, Androscoggin River,...

  4. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco


    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...... (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial...... DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM...

  5. Single-incision laparoscopic bariatric surgery

    Directory of Open Access Journals (Sweden)

    Huang Chih-Kun


    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.

  6. Of ice and water: Quaternary fluvial response to glacial forcing (United States)

    Cordier, Stéphane; Adamson, Kathryn; Delmas, Magali; Calvet, Marc; Harmand, Dominique


    Much research, especially within the framework of the Fluvial Archives Group, has focused on river response to climate change in mid-latitude non-glaciated areas, but research into the relationships between Quaternary glacial and fluvial dynamics remains sparse. Understanding glacial-fluvial interactions is important because glaciers are able to influence river behaviour significantly, especially during glacial and deglacial periods: (1) when they are located downstream of a pre-existing fluvial system and disrupt its activity, leading to hydrographical, hydrosedimentary and isostatic adjustments, and (2) when they are located upstream, which is a common scenario in mid-latitude mountains that were glaciated during Pleistocene cold periods. In these instances, glaciers are major water and sediment sources. Their role is particularly significant during deglaciation, when meltwater transfer towards the fluvial system is greatly increased while downstream sediment evacuation is influenced by changes to glacial-fluvial connectivity and basin-wide sediment storage. This means that discharge and sediment flux do not always respond simultaneously, which can lead to complex fluvial behaviour involving proglacial erosion and sedimentation and longer-term paraglacial reworking. These processes may vary spatially and temporally according to the position relative to the ice margin (ice-proximal versus ice-distal). With a focus on the catchments of Europe, this paper aims to review our understanding of glacial impacts on riversystem behaviour. We examine the methods used to unravel fluvial response to 'glacial forcing', and propose a synthesis of the behaviour of glacially-fed rivers, opening perspectives for further research.

  7. Fluvial geomorphic elements in modern sedimentary basins and their potential preservation in the rock record: A review (United States)

    Weissmann, G. S.; Hartley, A. J.; Scuderi, L. A.; Nichols, G. J.; Owen, A.; Wright, S.; Felicia, A. L.; Holland, F.; Anaya, F. M. L.


    Since tectonic subsidence in sedimentary basins provides the potential for long-term facies preservation into the sedimentary record, analysis of geomorphic elements in modern continental sedimentary basins is required to understand facies relationships in sedimentary rocks. We use a database of over 700 modern sedimentary basins to characterize the fluvial geomorphology of sedimentary basins. Geomorphic elements were delineated in 10 representative sedimentary basins, focusing primarily on fluvial environments. Elements identified include distributive fluvial systems (DFS), tributive fluvial systems that occur between large DFS or in an axial position in the basin, lacustrine/playa, and eolian environments. The DFS elements include large DFS (> 30 km in length), small DFS (uniformitarianism, sedimentary basins from the past most likely had a similar configuration of geomorphic elements. Facies distributions in tributary positions and those on DFS appear to display specific morphologic patterns. Tributary rivers tend to increase in size in the downstream direction. Because axial tributary rivers are present in confined settings in the sedimentary basin, they migrate back and forth within a relatively narrow belt (relative to the overall size of the sedimentary basin). Thus, axial tributary rivers tend to display amalgamated channel belt form with minimal preservation potential of floodplain deposits. Chute and neck cutoff avulsions are also common on meandering rivers in these settings. Where rivers on DFS exit their confining valley on the basin margin, sediment transport capacity is reduced and sediment deposition occurs resulting in development of a 'valley exit' nodal avulsion point that defines the DFS apex. Rivers may incise downstream of the basin margin valley because of changes in sediment supply and discharge through climatic variability or tectonic processes. We demonstrate that rivers on DFS commonly decrease in width down-DFS caused by infiltration

  8. Current Status of Single-incision Laparoscopic Surgery

    DEFF Research Database (Denmark)

    Ahmed, Irfan; Ciancio, Fabio; Ferrara, Vincenzo;


    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...... expectations for, the technique. The experts reached agreement on a number of statements and recommendations, which will support surgeons in adopting the technique. The panel agreed that the single-incision technique may offer a number of benefits to patients; however, further clinical data need...

  9. Fluvial erosion on Mars: Implications for paleoclimatic change (United States)

    Gulick, Virginia C.; Baker, Victor R.


    Fluvial erosion on Mars has been nonuniform in both time and space. Viking orbiter images reveal a variety of different aged terrains exhibiting widely different degrees of erosion. Based on our terrestrial analog studies, rates of fluvial erosion associated with the formation of many of the valleys on Mars is probably on the order of hundreds of meters per million years, while rates of erosion associated with the formation of the outflow channels probably ranged from tens to hundreds of meters in several weeks to months. However, estimated rates of erosion of the Martian surface at the Viking Lander sites are extremely low, on the order of 1 micron/yr or less. At most this would result in a meter of material removed per million years, and it is unlikely that such an erosion rate would be able to produce the degree of geomorphic work required to form the fluvial features present elsewhere on the surface. In addition, single terrain units are not eroded uniformly by fluvial processes. Instead fluvial valleys, particularly in the cratered highlands, typically are situated in clusters surrounded by vast expanses of uneroded surfaces of the same apparent lithologic, structural, and hydrological setting. Clearly throughout its geologic history, Mars has experienced a nonuniformity in erosion rates. By estimating the amount of fluvial erosion on dissected terrains and by studying the spatial distribution of those locations which have experienced above normal erosion rates, it should be possible to place further constraints on Mars' paleoclimatic history.

  10. Bar morphodynamics in the tidally-influenced fluvial zone (United States)

    Parsons, Daniel; Ashworth, Philip; Best, James; Nicholas, Andrew; Prokocki, Eric; Sambrook-Smith, Greg; Keevil, Claire; Sandbach, Steve


    The hydrodynamics and deposits of the Tidally-Influenced Fluvial Zone (TIFZ) are complex because it experiences competing fluvial and tidal flows and spatially and temporally variable rates of sediment transport and deposition. This paper presents a new integrated field dataset from the Columbia River Estuary, USA, that quantifies the morphodynamic response the bed morphology and bar stratigraphy to fluvial-tidal flows. A 3-year, field and modelling program that started in 2011, has been monitoring the dynamics and deposits of a 40 km-reach of the Columbia River Estuary. Data obtained so far throughout the TIFZ include: bathymetry using MBES, flow using ADCP, subsurface sedimentology using GPR and shallow coring to 5 m. Initial results from the programme suggest there is a complex spatial and temporal lag in the response of the bed morphology and deposits to the fluvial-tidal flows. Zones of strong ebb and flood flow do not necessarily produce channel beds dominated by bi-directional bedforms. Many mid-channel bars are stable over decadal time periods. This paper will illustrate the variety in bar morphologies and channel change throughout the fluvial-tidal zone and contrast these bar dynamics with examples from purely fluvial environments.

  11. Bar morphodynamics in the fluvial-tidal zone (United States)

    Ashworth, P. J.; Best, J. L.; Nicholas, A.; Parsons, D. R.; Prokocki, E.; Sambrook Smith, G.; Simpson, C.


    The hydrodynamics and deposits of the Tidally-Influenced Fluvial Zone (TIFZ) are complex because it experiences competing fluvial and tidal flows, sometimes moderated by waves, and spatially and temporally variable rates of sediment transport and deposition. This paper presents a new integrated field dataset from the Columbia River Estuary, USA, that quantifies the response of the flow structure, bed morphology and bar stratigraphy to fluvial-tidal flows. A new 3-year, field and modelling program that started in 2011, has been monitoring the dynamics and deposits of a 40 km-reach of the Columbia River Estuary. Data obtained so far throughout the TIFZ include: bathymetry using MBES, flow using ADCP, subsurface sedimentology using GPR and shallow coring to 5 m. First results suggest there is a complex spatial and temporal lag in the response of the bed morphology and deposits to the fluvial-tidal flows. Zones of strong ebb and flood flow do not necessarily produce channel beds dominated by bi-directional bedforms. Many mid-channel bars are stable over decadal time periods. This paper will illustrate the variety in bar morphologies and channel change throughout the fluvial-tidal zone and contrast these bar dynamics with examples from purely fluvial environments.

  12. Laparoscopic vs mini-incision open appendectomy

    Institute of Scientific and Technical Information of China (English)

    Fatih; ?ift?i


    AIM: To compare laparoscopic vs mini-incision open appendectomy in light of recent data at our centre.METHODS: The data of patients who underwen appendectomy between January 2011 and June 2013 were collected. The data included patients’ demographic data, procedure time, length of hospital stay, the need for pain medicine, postoperative visual analog scale o pain, and morbidities. Pregnant women and patients with previous lower abdominal surgery were excluded Patients with surgery converted from laparoscopic appendectomy(LA) to mini-incision open appendectomy(MOA) were excluded. Patients were divided into two groups: LA and MOA done by the same surgeon. The patients were randomized into MOA and LA groups a computer-generated number. The diagnosis of acute appendicitis was made by the surgeon with physica examination, laboratory values, and radiological tests(abdominal ultrasound or computed tomography). Al operations were performed with general anaesthesia The postoperative vision analog scale score was recorded at postoperative hours 1, 6, 12, and 24. Patients were discharged when they tolerated normal food and passed gas and were followed up every week for three weeks as outpatients.RESULTS: Of the 243 patients, 121(49.9%) underwen MOA, while 122(50.1%) had laparoscopic appendectomy There were no significant differences in operation time between the two groups(P = 0.844), whereas the visua analog scale of pain was significantly higher in the open appendectomy group at the 1st hour(P = 0.001), 6th hour(P = 0.001), and 12 th hour(P = 0.027). The need for analgesic medication was significantly higher in the MOA group(P = 0.001). There were no differences between the two groups in terms of morbidity rate(P = 0.599)The rate of total complications was similar between the two groups(6.5% in LA vs 7.4% in OA, P = 0.599). Al wound infections were treated non-surgically. Six ou of seven patients with pelvic abscess were successfully treated with percutaneous drainage; one

  13. Mini-incision microdissection testicular sperm extraction: a useful technique for men with cryptozoospermia. (United States)

    Alrabeeah, K; Witmer, J; Ruiz, S; AlMalki, A; Phillips, S; Zini, A


    Microdissection testicular sperm extraction (micro-TESE) was developed to minimize the testicular injury associated with multiple open TESEs. We sought to evaluate a mini-incision micro-TESE in men with cryptozoospermia and non-obstructive azoospermia (NOA). We conducted a retrospective study of 26 consecutive men with NOA and cryptozoospermia who underwent a primary (first) micro-TESE between March 2015 and August 2015. Final assessment of sperm recovery (reported on the day of intra-cytoplasmic sperm injection (ICSI)) was recorded as (i) successful (available spermatozoa for ICSI) or (ii) unsuccessful (no spermatozoa for ICSI). The decision to perform a mini-incision micro-TESE (with limited unilateral micro-dissection) or standard/extensive (with unilateral or bilateral micro-dissection) was guided by the intra-operative identification of sperm recovery (≥5 spermatozoa) from the first testicle. Overall, sperm recovery was successful in 77% (20/26) of the men. In 37% of the men (8/26), the mini-incision micro-TESE was successful (positive sperm recovery). The remaining 18 men required a standard (extensive) microdissection: 61% (11/18) underwent a unilateral and 39% (7/18) a bilateral micro-TESE. We found that 90% (9/10) of the men with cryptozoospermia and 63% (10/16) of the men with NOA underwent a unilateral (mini or standard micro-TESE). The mini-incision micro-TESE allowed for successful sperm recovery in 60% (6/10) of the men with cryptozoospermia and 13% (2/16) of the men with NOA. The data demonstrate that a mini-incision micro-TESE together with rapid intra-operative assessment and identification of spermatozoa recovery can be useful in men undergoing microTESE, particularly, men with cryptozoospermia.

  14. Laparoscopic Appendectomy versus Mini-Incision Appendectomy in Patients with Lower Body Mass Index and Noncomplicated Appendicitis

    Directory of Open Access Journals (Sweden)

    İsmail Özsan


    Full Text Available Laparoscopic appendectomy has become favored over open surgical methods for its association with decreased postoperative pain, more rapid return to daily activities, and improved cosmetic results. Mini-incision appendectomy was being performed in our clinic for a long time especially in patients with noncomplicated appendicitis and in patients with appropriate body mass index. Although laparoscopy presents obvious advantages especially for obese patients and young women, with respect to the results of our study, mini-incision appendectomy seems to be an alternative for selected patient groups.

  15. Isolated subtalar arthrodesis through minimal incision surgery. (United States)

    Carranza-Bencano, A; Tejero-García, S; Del Castillo-Blanco, G; Fernández-Torres, J J; Alegrete-Parra, A


    In recent years there has been an increase in the use of minimally invasive techniques, such as arthroscopy, percutaneous, and minimally invasive incisions, for foot and ankle surgery. The purpose of this study was to analyze the fusion rate and clinical results of isolated subtalar arthrodesis (ISA) using the novel and original technique of minimal incision surgery (MIS). There were a total of 77 feet in 76 patients who underwent ISA and were followed for 50 months on average (range, 15-108). The first 30 cases were evaluated retrospectively, and 47 cases were evaluated prospectively. MIS without tourniquet was used in all cases and fusion was assessed radiographically and clinically. Clinical outcome measures used were the Angus and Cowell Scoring System, AOFAS Ankle-Hindfoot, the SF-36, and a patient satisfaction questionnaire 12 months after the intervention. Radiographic and clinical consolidation was achieved in 92% of cases. Main outcomes were "good" in 57 patients as determined by the Angus and Cowell criteria, with 13 "fair" and 7 "poor" results. In the prospective group, AOFAS scores improved by 47.6 points (95% CI: 50.7-42.5) 12 months after surgical intervention. SF-36 outcomes improved by 14.5 points (95% CI: 11.58-17.31) in the mental summary component and 4.2 points (95% CI: 2.2-6.1) in the physical summary component. We recorded no cases of early complications such as wound infections, neurovascular damage, or delayed wound healing. To our knowledge, the present series represents the largest study on subtalar arthrodesis using minimally invasive surgery. The data obtained showed a similar rate of bony union and clinical outcomes compared with the literature, but without early wound complications. ISA using the MIS technique was a good option for patients at greater risk of wound healing complications. Level IV, case series.

  16. Large-scale coastal and fluvial models constrain the late Holocene evolution of the Ebro Delta (United States)

    Nienhuis, Jaap H.; Ashton, Andrew D.; Kettner, Albert J.; Giosan, Liviu


    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.

  17. Single-Incision Laparoscopic Surgery (SILS Assisted Sigma Resection Via Pfannenstiel Incision for Complicated Diverticulitis

    Directory of Open Access Journals (Sweden)

    Arne Dietrich


    Results: The operation time ranged from 89 to 280 min. There were no conversions, and no additional trocars were used. The postoperative hospital stay ranged from 5 to 14 days. All patients were discharged without any intraoperative or postoperative complications. Conclusions: SILS sigma or anterior rectum resection for complicated diverticulitis can be performed via a Pfannenstiel incision. This approach provides direct visualization and access into the pelvis as well as the option to benefit from open surgery devices. The Pfannenstiel incision may generally be recommended for the favorable cosmetic effect and the very low rate of incisional hernias, as reported in the literature. [Arch Clin Exp Surg 2014; 3(1.000: 10-15

  18. Transurethral incision of urethral diverticulum in the female

    DEFF Research Database (Denmark)

    Miskowiak, J; Honnens de Lichtenberg, M


    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....

  19. The stream channel incision syndrome and water quality (United States)

    Watershed development often triggers channel incision, which accounts for 60-90% of sediments leaving many disturbed watersheds. Impacts of such incision on water quality processes and the implication of such impairment on stream biota are relevant to issues associated with establishing total maxim...

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

    DEFF Research Database (Denmark)

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


    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...... as conventional laparoscopic 4-port cholecystectomy or as single-incision laparoscopic cholecystectomy....

  1. Modeling the Evolution of Incised Streams: III. Model Application (United States)

    Incision and ensuing widening of alluvial stream channels is widespread in the midsouth and midwestern United States and represents an important form of channel adjustment. Two accompanying papers have presented a robust computational model for simulating the long-term evolution of incised and resto...

  2. SMA Syndrome Treated by Single Incision Laparoscopic Duodenojejunostomy. (United States)

    Kim, Sungsoo; Kim, Yoo Seok; Min, Young-Don


    Superior mesenteric artery (SMA) syndrome is a mechanical duodenal obstruction by the SMA. The traditional approach to SMA syndrome was open bypass surgery. Nowadays, a conventional approach has been replaced by laparoscopic surgery. But single incision laparoscopic approach for SMA syndrome is rare. Herein, we report the first case of SMA syndrome patient who was treated by single incision laparoscopic duodenojejunostomy.

  3. Single incision laparoscopic right hemicolectomy:different approaches

    Institute of Scientific and Technical Information of China (English)

    WONG Tak-man; DAY Weida; KWOK Shu-yan; LAU Ying-yu Patrick; YIP Wai-chun Andrew


    Background Single incision laparoscopic colectomy has been performed in recent years,and has been shown to be feasible and safe.This study was to assess the feasibility of single incision laparoscopic right hemicolectomy and to compare the differences in different approaches.Methods This retrospective study included eighteen patients with carcinoma of caecum and ascending colon,undergoing single incision laparoscopic right hemicolectomy.This study also compared single incision laparoscopic right hemicolectomy using different approaches:(1) single incision multiport,(2) single access port and (3) glove port.Results There was no statistical difference in surgical outcomes.Concerning the surgeon's satisfaction toward three methods,overcrowding and durability were similar but the single incision multiport was associated with the highest gas-leak and the "glove" port was associated with poor durability.However,the method of single incision multiport has the lowest average cost of the special trocar or port in each operation.The operative time and blood loss of the operations in this study were comparable to previous publications.Conclusion There was no significant difference between different approaches of single incision laparoscopic right hemicolectomy for colonic cancer in right side colon.

  4. Marine intervals in Neogene fluvial deposits of western Amazonia (United States)

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


    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.

  5. Minimally invasive two-incision total hip arthroplasty:a short-term retrospective report of 27 cases

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-long; WANG Qi; SHEN Hao; JIANG Yao; ZENG Bing-fang


    Background Total hip arthroplasty (THA) is widely applied for the treatment of end-stage painful hip arthrosis.Traditional THA needed a long incision and caused significant soft tissue trauma. Patients usually required long recovery time after the operation. In this research we aimed to study the feasibility and clinical outcomes of minimally invasive two-incision THA.Methods From February 2004 to March 2005, 27 patients, 12 males and 15 females with a mean age of 71 years (55-76), underwent minimally invasive two-incision THA in our department. The patients included 9 cases of osteoarthritis, 10 cases of osteonecrosis, and 8 cases of femoral neck fracture. The operations were done with VerSys cementless prosthesis and minimally invasive instruments from Zimmer China. Operation time, blood loss, length of incision, postoperative hospital stay, and complications were observed.Results The mean operation time was 90 minutes (80-170 min). The mean blood loss was 260 ml (170-450 ml) and blood transfusion was carried out in 4 cases of femoral neck fracture (average 400 ml). The average length of the anterior incision was 5.0 cm (4.6-6.5 cm) and of the posterior incision 3.7 cm (3.0-4.2 cm). All of the patients were ambulant the day after surgery. Nineteen patients were discharged 5 days post-operatively and 8 patients 7 days post-operatively. The patients were followed for 18 months (13-25 months). One patient was complicated by a proximal femoral fracture intraoperatively. No other complications, including infections, dislocations, and vascular injuries, occurred. The mean Harris score was 94.5 (92-96).Conclusions Two-incision THA has the advantage of being muscle sparing and minimally invasive with less blood loss and rapid recovery. However, this technique is time consuming, technically demanding, and requires fluoroscopy.

  6. First Canadian experience with robotic single-incision pyeloplasty: Comparison with multi-incision technique (United States)

    Law, Jeffrey; Rowe, Neal; Archambault, Jason; Nastis, Sofia; Sener, Alp; Luke, Patrick P.


    Introduction: We compared the outcomes of single-incision, robot-assisted laparoscopic pyeloplasty vs. multiple-incision pyeloplasty using the da Vinci robotic system. Methods: We reviewed all consecutive robotic pyeloplasties by a single surgeon from January 2011 to August 2015. A total of 30 procedures were performed (16 single:14 multi-port). Two different single-port devices were compared: the GelPort (Applied Medical, Rancho Santa Margarita, CA) and the Intuitive single-site access port (Intuitive Surgical, Sunnyvale, CA). Results: Patient demographics were similar between the two groups. Mean operating time was similar among the single and multi-port groups (225.2 min vs. 198.9 minutes [p=0.33]). There was no significant difference in length of hospital stay in either group (86.2 hr vs. 93.2 hr [p=0.76]). There was no difference in success rates or postoperative complications among groups. Conclusions: Single-port robotic pyeloplasty is non-inferior to multiple-incision robotic surgery in terms of operative times, hospitalization time, success rates, and complications. Verifying these results with larger cohorts is required prior to the wide adoption of this technique. Ongoing objective measurements of cosmesis and patient satisfaction are being evaluated. PMID:27217850

  7. Global effects of agriculture on fluvial dissolved organic matter. (United States)

    Graeber, Daniel; Boëchat, Iola G; Encina-Montoya, Francisco; Esse, Carlos; Gelbrecht, Jörg; Goyenola, Guillermo; Gücker, Björn; Heinz, Marlen; Kronvang, Brian; Meerhoff, Mariana; Nimptsch, Jorge; Pusch, Martin T; Silva, Ricky C S; von Schiller, Daniel; Zwirnmann, Elke


    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 (DOM), which constitutes the main vector of carbon transport from soils to fluvial networks and to the sea, and is involved in a large variety of biogeochemical processes. Here, we provide first evidence about the wider occurrence of agricultural impacts on the concentration and composition of fluvial DOM across climate zones of the northern and southern hemispheres. Both extensive and intensive farming altered fluvial DOM towards a more microbial and less plant-derived composition. Moreover, intensive farming significantly increased dissolved organic nitrogen (DON) concentrations. The DOM composition change and DON concentration increase differed among climate zones and could be related to the intensity of current and historical nitrogen fertilizer use. As a result of agriculture intensification, increased DON concentrations and a more microbial-like DOM composition likely will enhance the reactivity of catchment DOM emissions, thereby fuelling the biogeochemical processing in fluvial networks, and resulting in higher ecosystem productivity and CO2 outgassing.

  8. 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.


    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.

  9. Dating Fluvial Floodplains and Quantifying Channel Migration Rates Using Short-Lived Radioisotopes (United States)

    Black, E. E.; Renshaw, C. E.; Kaste, J. M.; Magilligan, F. J.; Dade, W. B.


    A variety of methods, including dendrochronolgy and aerial photography, have been used previously to quantify fluvial channel geometry changes and lateral migration rates on time scales of tens to hundreds of years. However, no universally satisfactory technique has emerged due to various limitations of each method. We explore the novel technique of using short-lived radionuclides to date fluvial surfaces with the goal of determining lateral migration rates. In particular, we use 210Pb (t(1/2) ~ 22.3 years) in floodplain sediment to determine the lateral migration rates of regulated reaches on the Genesee River, NY, and unregulated reaches on the Winooski River, VT and the upper Connecticut River, NH. Surface ages and lateral migration rates are compared to those determined using historical aerial photography. Preliminary analyses of sediment cores are consistent with the general trend of surface ages recorded in the aerial photography, but the absolute ages of the surfaces indicate that inheritance of 210Pb within the deposited sediment affects the surface ages. Furthermore, the temporal resolution of the method is much greater in areas with rapid migration over the past 50 years than in those areas with similarly rapid migration occurring in years prior to 1960.

  10. Tectonic, climatic, and anthropogenic influences on ultra-high rate of bedrock incision in the Ta-An River Gorge, western Taiwan (United States)

    Chen, M.; Lee, J.; Hsieh, M.; Chan, Y.; Frankel, K.


    We characterize geomorphic features of a bedrock gorge with a 12-m-high knickpoint formed in the lower Ta- An River near Diaoshenshan, Taiwan that has experienced 20 to 30 m of incision since 1999. Although the same spot was uplifted 10 m during the 1999 Mw = 7.6 Chi-Chi earthquake, this amount of coseismic displacement does not fully explain the overdeepening of the channel longitudinal profile. This study focuses on a ~ 4 km reach of the lower Ta-An River, which is underlain by interbedded sandstone and shale, with the pop-up structure in the uppermost 1 km. A 700-m-long, > 20-m-deep bedrock gorge is located along this reach. River discharge and geomorphic data including knickpoint location, channel slope, depth of gorge, and height of hanging valleys are utilized to derive rates, patterns, and evolution of the bedrock incision. Two stages of fluvial incision are identified in the gorge zone: (1) 3 to 5 m of total incision from 1999 to 2003, and (2) 15 to 20 m of total incision since 2004. The knickpoint is migrating upstream at a rate of approximately 100 m/yr, which has elongated the extent of the gorge from the west limit of the pop-up structure since 2004. Significant amounts of knickpoint retreat occur during the annual summer typhoon season. We interpret that the Ta-An River responded to the 1999 coseismic uplift in the first stage of incision in similar fashion to the Ta-Chia River, located 5 km to the south. The accelerated bedrock incision in the second stage, which deepened the bedrock gorge since 2004, is correlated with human-induced sediment supply change and large flooding events. Heavy sediment mining over the study area since the post- earthquake period and closure of the Shihlin Dam 15 km upstream significantly decreased sediment supply to the channel. Moreover, both yearly precipitation and river discharge from 2003 to the present are significantly above average for the past 105 and 32 years. In 2005, the 33 year maximum daily discharge of 3679

  11. 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


    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

  12. The Surgical Release of Dupuytren's Contracture Using Multiple Transverse Incisions

    Directory of Open Access Journals (Sweden)

    Hyunjic Lee


    Full Text Available Dupuytren's contracture is a condition commonly encountered by hand surgeons, although it is rare in the Asian population. Various surgical procedures for Dupuytren's contracture have been reported, and the outcomes vary according to the treatment modalities. We report the treatment results of segmental fasciectomies with multiple transverse incisions for patients with Dupuytren's contracture. The cases of seven patients who underwent multiple segmental fasciectomies with multiple transverse incisions for Dupuytren's contracture from 2006 to 2011 were reviewed retrospectively. Multiple transverse incisions to the severe contracture sites were performed initially, and additional incisions to the metacarpophalangeal (MCP joints, and the proximal interphalangeal (PIP joints were performed if necessary. Segmental fasciectomies by removing the fibromatous nodules or cords between the incision lines were performed and the wound margins were approximated. The mean range of motion of the involved MCP joints and PIP joints was fully recovered. During the follow-up periods, there was no evidence of recurrence or progression of disease. Multiple transverse incisions for Dupuytren's contracture are technically challenging, and require a high skill level of hand surgeons. However, we achieved excellent correction of contractures with no associated complications. Therefore, segmental fasciectomies with multiple transverse incisions can be a good treatment option for Dupuytren's contracture.

  13. The Surgical Release of Dupuytren's Contracture Using Multiple Transverse Incisions

    Directory of Open Access Journals (Sweden)

    Hyunjic Lee


    Full Text Available Dupuytren’s contracture is a condition commonly encountered by hand surgeons, although itis rare in the Asian population. Various surgical procedures for Dupuytren’s contracture havebeen reported, and the outcomes vary according to the treatment modalities. We report thetreatment results of segmental fasciectomies with multiple transverse incisions for patientswith Dupuytren’s contracture. The cases of seven patients who underwent multiple segmentalfasciectomies with multiple transverse incisions for Dupuytren’s contracture from 2006 to 2011were reviewed retrospectively. Multiple transverse incisions to the severe contracture sites wereperformed initially, and additional incisions to the metacarpophalangeal (MCP joints, and theproximal interphalangeal (PIP joints were performed if necessary. Segmental fasciectomiesby removing the fibromatous nodules or cords between the incision lines were performed andthe wound margins were approximated. The mean range of motion of the involved MCP jointsand PIP joints was fully recovered. During the follow-up periods, there was no evidence ofrecurrence or progression of disease. Multiple transverse incisions for Dupuytren’s contractureare technically challenging, and require a high skill level of hand surgeons. However, weachieved excellent correction of contractures with no associated complications. Therefore,segmental fasciectomies with multiple transverse incisions can be a good treatment option forDupuytren’s contracture.

  14. Late Quaternary incision and deposition in an active volcanic setting: The Volturno valley fill, southern Italy (United States)

    Amorosi, Alessandro; Pacifico, Annamaria; Rossi, Veronica; Ruberti, Daniela


    Extensive illustration of depositional facies, ostracod and foraminiferal assemblages, and Late Quaternary stratigraphic architecture is offered for the first time from beneath the modern coastal plain of Volturno River, the longest river in southern Italy. Proximity to an active volcanic district, including quiescent Vesuvius Volcano, provides an easily identifiable stratigraphic marker (Campania Grey Tuff or CGT), up to 55 m thick, emplaced 39 ky cal BP by a large-volume explosive pyroclastic eruption. Identification of top CGT to a maximum depth of 30 m allows tracing out the shape of a 15-20 km wide Late Quaternary palaeovalley incised by Volturno River into the thick ignimbritic unit immediately after its deposition. A terraced palaeotopography of the valley flanks is reconstructed on the basis of core data. Above the basal fluvial deposits, the early Holocene transgressive facies consist of a suite of estuarine (freshwater to brackish) deposits. These are separated from overlying transgressive barrier sands by a distinctive wave ravinement surface. Upwards, a distinctive shallowing-upward succession of middle-late Holocene age is interpreted to reflect initiation and subsequent progradation of a wave-dominated delta system, with flanking strandplains, in response to reduced rate of sea-level rise. The turnaround from transgressive to highstand conditions is identified on the basis of subtle changes in the meiofauna. These enable tracking of the maximum flooding surface into its updip (lagoonal/estuarine) counterpart, thus highlighting the role of refined palaeontological criteria as a powerful tool for high-resolution sequence-stratigraphic studies.

  15. Mio-Pliocene morphotectonic evolution of the Iranian Plateau: from outward expansion to incision and excavation (United States)

    Ballato, Paolo; Heidarzadeh, Ghasem; Zeilinger, Gerold; Ghassemi, Mohammad; Cifelli, Francesca; Mattei, Massimo; Hassanzadeh, Jamshid; Balling, Philipp; Dunkl, István; Sudo, Masafumi; Mulch, Andreas; Strecker, Manfred


    Located along plate convergence zones, high orogenic plateaus form extensive and elevated morphotectonic provinces that are flanked by high mountain ranges at their margins. The Iranian Plateau (IP) is a prominent NW-SE striking (ca. 1500 km in length for a width of 140 to 260 km), elevated (> 50% lies between 1.5 and 2 km of elevation), mostly internally drained (at present ca. 55% has internal drainage), arid (mean annual precipitation ranging from 0.1 to 50 km of distance) of conglomerates in the distal sectors of the basin. This event was followed by basin uplift and erosion with a shift of the basin depocenter toward the outer margin of the plateau (to the N and NE; Zanjan and Mianeh basins). There, sedimentation lasted until fluvial incision and basin excavation of sub-horizontal sediments started sometime during the last 4 Ma. Overall, our data suggest that sedimentation took place in a contiguous foreland-basin system, most likely triggered by thrust stacking and topographic loading in the interior of the plateau from ~17 Ma. The outward N to NE-directed propagation of the deformation fronts (< 10.5 Ma) excised parts of the foreland, incorporating new basin sectors into the orogenic plateau and compartmentalizing the foreland into a contractional basin and range topography. This implies that the IP developed during crustal shortening and thickening processes and that sometime after 10.5 Ma the northern IP had reached a lateral size similar to the modern one.

  16. On the control of riverbed incision induced by run-of-river power plant (United States)

    Bizzi, Simone; Dinh, Quang; Bernardi, Dario; Denaro, Simona; Schippa, Leonardo; Soncini-Sessa, Rodolfo


    Water resource management (WRM) through dams or reservoirs is worldwide necessary to support key human-related activities, ranging from hydropower production to water allocation and flood risk mitigation. Designing of reservoir operations aims primarily to fulfill the main purpose (or purposes) for which the structure has been built. However, it is well known that reservoirs strongly influence river geomorphic processes, causing sediment deficits downstream, altering water, and sediment fluxes, leading to riverbed incision and causing infrastructure instability and ecological degradation. We propose a framework that, by combining physically based modeling, surrogate modeling techniques, and multiobjective (MO) optimization, allows to include fluvial geomorphology into MO optimization whose main objectives are the maximization of hydropower revenue and the minimization of riverbed degradation. The case study is a run-of-the-river power plant on the River Po (Italy). A 1-D mobile-bed hydro-morphological model simulated the riverbed evolution over a 10 year horizon for alternatives operation rules of the power plant. The knowledge provided by such a physically based model is integrated into a MO optimization routine via surrogate modeling using the response surface methodology. Hence, this framework overcomes the high computational costs that so far hindered the integration of river geomorphology into WRM. We provided numerical proof that river morphologic processes and hydropower production are indeed in conflict but that the conflict may be mitigated with appropriate control strategies.

  17. New interpretations of fluvial sediments from the Kras

    Directory of Open Access Journals (Sweden)

    Andrej Mihevc


    Full Text Available Important unroofed caves with fluvial sediments from Divaški kras, Matarsko podolje and Podgorski kras are presented. Extend of the phenomena and relation to the existing caves and karst surface and geomorphological meaning of them are described. Sediments from them were analysed and dated with different methods. The largest age of the sediment was found in the unroofed cave excavated in Črnotiče quarry. In the cave wall fossil remains of stygobiont Marifugia cavatica were covered by 3.2-4.1 Ma old fluvial sediments.

  18. Fusion of Remote Sensing Methods, UAV Photogrammetry and LiDAR Scanning products for monitoring fluvial dynamics (United States)

    Lendzioch, Theodora; Langhammer, Jakub; Hartvich, Filip


    Fusion of remote sensing data is a common and rapidly developing discipline, which combines data from multiple sources with different spatial and spectral resolution, from satellite sensors, aircraft and ground platforms. Fusion data contains more detailed information than each of the source and enhances the interpretation performance and accuracy of the source data and produces a high-quality visualisation of the final data. Especially, in fluvial geomorphology it is essential to get valuable images in sub-meter resolution to obtain high quality 2D and 3D information for a detailed identification, extraction and description of channel features of different river regimes and to perform a rapid mapping of changes in river topography. In order to design, test and evaluate a new approach for detection of river morphology, we combine different research techniques from remote sensing products to drone-based photogrammetry and LiDAR products (aerial LiDAR Scanner and TLS). Topographic information (e.g. changes in river channel morphology, surface roughness, evaluation of floodplain inundation, mapping gravel bars and slope characteristics) will be extracted either from one single layer or from combined layers in accordance to detect fluvial topographic changes before and after flood events. Besides statistical approaches for predictive geomorphological mapping and the determination of errors and uncertainties of the data, we will also provide 3D modelling of small fluvial features.

  19. Digital stereo photogrammetry for grain-scale monitoring of fluvial surfaces: Error evaluation and workflow optimisation (United States)

    Bertin, Stephane; Friedrich, Heide; Delmas, Patrice; Chan, Edwin; Gimel'farb, Georgy


    Grain-scale monitoring of fluvial morphology is important for the evaluation of river system dynamics. Significant progress in remote sensing and computer performance allows rapid high-resolution data acquisition, however, applications in fluvial environments remain challenging. Even in a controlled environment, such as a laboratory, the extensive acquisition workflow is prone to the propagation of errors in digital elevation models (DEMs). This is valid for both of the common surface recording techniques: digital stereo photogrammetry and terrestrial laser scanning (TLS). The optimisation of the acquisition process, an effective way to reduce the occurrence of errors, is generally limited by the use of commercial software. Therefore, the removal of evident blunders during post processing is regarded as standard practice, although this may introduce new errors. This paper presents a detailed evaluation of a digital stereo-photogrammetric workflow developed for fluvial hydraulic applications. The introduced workflow is user-friendly and can be adapted to various close-range measurements: imagery is acquired with two Nikon D5100 cameras and processed using non-proprietary "on-the-job" calibration and dense scanline-based stereo matching algorithms. Novel ground truth evaluation studies were designed to identify the DEM errors, which resulted from a combination of calibration errors, inaccurate image rectifications and stereo-matching errors. To ensure optimum DEM quality, we show that systematic DEM errors must be minimised by ensuring a good distribution of control points throughout the image format during calibration. DEM quality is then largely dependent on the imagery utilised. We evaluated the open access multi-scale Retinex algorithm to facilitate the stereo matching, and quantified its influence on DEM quality. Occlusions, inherent to any roughness element, are still a major limiting factor to DEM accuracy. We show that a careful selection of the camera

  20. Quantifying fluvial topography using UAS imagery and SfM photogrammetry (United States)

    Woodget, Amy; Carbonneau, Patrice; Visser, Fleur; Maddock, Ian; Habit, Evelyn


    The measurement and monitoring of fluvial topography at high spatial and temporal resolutions is in increasing demand for a range of river science and management applications, including change detection, hydraulic models, habitat assessments, river restorations and sediment budgets. Existing approaches are yet to provide a single technique for rapidly quantifying fluvial topography in both exposed and submerged areas, with high spatial resolution, reach-scale continuous coverage, high accuracy and reasonable cost. In this paper, we explore the potential of using imagery acquired from a small unmanned aerial system (UAS) and processed using Structure-from-Motion (SfM) photogrammetry for filling this gap. We use a rotary winged hexacopter known as the Draganflyer X6, a consumer grade digital camera (Panasonic Lumix DMC-LX3) and the commercially available PhotoScan Pro SfM software (Agisoft LLC). We test the approach on three contrasting river systems; a shallow margin of the San Pedro River in the Valdivia region of south-central Chile, the lowland River Arrow in Warwickshire, UK, and the upland Coledale Beck in Cumbria, UK. Digital elevation models (DEMs) and orthophotos of hyperspatial resolution (0.01-0.02m) are produced. Mean elevation errors are found to vary somewhat between sites, dependent on vegetation coverage and the spatial arrangement of ground control points (GCPs) used to georeference the data. Mean errors are in the range 4-44mm for exposed areas and 17-89mm for submerged areas. Errors in submerged areas can be improved to 4-56mm with the application of a simple refraction correction procedure. Multiple surveys of the River Arrow site show consistently high quality results, indicating the repeatability of the approach. This work therefore demonstrates the potential of a UAS-SfM approach for quantifying fluvial topography.

  1. Coarse sediment dynamics in a proglacial fluvial system (Fagge River, Tyrol) (United States)

    Baewert, Henning; Morche, David


    Alpine regions are strongly affected by the global climate change. Alpine glaciers have had a negative net balance since the end of the Little Ice Age (LIA). Proglacial areas with freshly exposed subglacial sediments are expanding due to the retreat of glaciers. These sediments (moraines, tills, glaciofluvial deposits, etc.) are unconsolidated, nearly unvegetated and therefore unstable and highly vulnerable to surface changes triggered by geomorphological processes. Particularly during heavy rainfall events, glacial and glaciofluvial deposits are remobilized and transported within the fluvial system. This study is focused on rapidly changing surfaces in the proglacial fluvial system of the Fagge River, which drains the Gepatschferner, one of the biggest glaciers in Austria, and is located in the Kaunertal/Austria. The field site covers an area from the snout of the glacier (2206 m a.s.l.) to the outlet of the Fagge River into the Gepatsch Reservoir at (1750 m a.s.l.). The main goal of this study is to measure surface changes and quantify mass balances of important sediment sources (alluvial plains, bars) in the proglacial area, which are directly connected to the fluvial system. For this purpose, multiple terrestrial laser scans are performed with an Optech ILRIS-36D laser scanner. During the field season in 2011 and 2012, several sediment sources were scanned at least twice. Significant surface changes occurred during the investigation period, mainly caused by an extreme flood event after heavy rain on August 26, 2012. Large amounts of sediment (> 70,000 m3) were remobilized, especially in the upper parts of the proglacial area, and were accumulated further downstream during this event.


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    Full Text Available MATERIAL & METHODS : This randomized , prospective study was carried out on patient attending out patients department of ophthalmology L . L . R . hospital ( G S V M Medical College Kanpur during the time period of 2 years . Detailed history , general examination & ophthalmic examination done . Then they under went Dacryocystorhinostomy surgery . These patients divided into two groups the Group ‘A’ and Group ‘B’ . Group . A patients underwent the dacryocystorhinostomy surgery with manual scalpel incision and Group B patients underwent the surgery with radiofrequency tools . The subsequent follow up was done at the intervals at one week , 3 weeks , 6 weeks and 6 months . Some w ere followed more frequently whenever needed . RESULTS : The present study was conducted on 118 eyes of 102 patients , o f these 56 eyes ( 48 patients received skin incision with manual scalpel ( Group ‘A’ and 62 eyes ( 54 patients received skin incision with r adiofrequency knife ( Group ‘B’ . The intraoperative bleeding and mean surgical time per case was less with rad i frequency knife that is in group B . There was also faster wound healing with more numbers cases of excellent scar quality on postoperative follo w up in Group B . DISCUSSION : Intraoperative average numbers of gauze pieces used per case was less in Group B because of electrocoagulation action of radiofrequency tools . That is why the mean surgical time per case was less in Group B . Patients was compar ed for scar quality by giving them scores according to Manchester scar scale score and60% patients in Group B achieves excellent scar quality scores in comparison to group A in which only 48% patients achieves excellent scar quality scores . CONCLUSION : There is less intraoperative bleeding and less mean surgical time per case and faster healing with excellent scar quality postoperatively in early and late follow ups with radiofrequency tools than manual scalpel .

  3. 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 (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.


    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

  4. Titan's fluvial valleys: Morphology, distribution, and spectral properties (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, C.; Barnes, J.W.; Nelson, R.


    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

  5. Terrace styles and timing of terrace formation in the Weser and Leine valleys, northern Germany: Response of a fluvial system to climate change and glaciation (United States)

    Winsemann, Jutta; Lang, Jörg; Roskosch, Julia; Polom, Ulrich; Böhner, Utz; Brandes, Christian; Glotzbach, Christoph; Frechen, Manfred


    In glaciated continental basins accommodation space is not only controlled by tectonics and sea-level but also by the position of ice-sheets, which may act as a regional base-level for fluvial systems. Although the Pleistocene terrace record of major river systems in northwestern Europe has been investigated by many authors, relatively little attention has been paid to base-level changes related to glacier advance-retreat cycles and how these regional changes in base-level interacted with river catchment processes. This study provides a synthesis of the stratigraphic architecture of Middle Pleistocene to Holocene fluvial terraces in the upper Weser and middle Leine valley in northern Germany and links it to glaciation, climate and base-level change. The depositional architecture of the fluvial terrace deposits has been reconstructed from outcrops and high-resolution shear wave seismic profiles. The chronology is based on luminescence ages, 230Th/U ages, 14C ages and Middle Palaeolithic archaeological assemblages. The drainage system of the study area developed during the Early Miocene. During the Pleistocene up to 170 m of fluvial incision took place. A major change in terrace style from strath terraces to cut-and-fill terraces occurred during the early Middle Pleistocene before Marine Isotope Stage MIS 12, which may correlate with climate deterioration and the onset of glaciation in northern central Europe. During this time a stable buffer zone was established within which channels avulsed and cut and filled freely without leaving these vertical confines. Climate was the dominant driver for river incision and aggradation, whereas the terrace style was controlled by base-level changes during ice-sheet growth and decay. A major effect of glacio-isostatic processes was the post-Elsterian re-direction of the River Weser and River Leine. The Middle Pleistocene fluvial terraces are vertically stacked, indicating a high aggradation to degradation ratio, corresponding

  6. Techniques for posterior lamellar keratoplasty through a scleral incision

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    Melles, GRJ; Kamminga, N


    Purpose. To describe several techniques for posterior lamellar keratoplasty through a scleral incision, for management of corneal endothelial disorders like pseudophacic bullous keratopathy and Fuchs' endothelial dystrophy, and to report the mid-term clinical results. Methods. Three techniques have

  7. Single-incision laparoscopic management of a giant hepatic cyst. (United States)

    Willems, Kaitlin; Monsivais, Sharon; Vassaur, Hannah; Buckley, Francis P


    Large symptomatic hepatic cysts may warrant surgical management. Traditional multiport laparoscopic technique is typically preferred over open laparotomy, but the use of the single-incision laparoscopic approach for this diagnosis is not well documented. Here, we describe the case of a 68-year-old woman who underwent complete anterior wall fenestration, excision and cauterization of a simple hepatic cyst via a single-incision laparoscopic technique through an incision at the umbilicus. The objective of this case report is to document single-incision laparoscopy as a safe, feasible and cosmetically appealing approach for the management of a large hepatic cyst. Published by Oxford University Press and JSCR Publishing Ltd. All rights reserved. © The Author 2015.

  8. A model of plant strategies in fluvial hydrosystems

    NARCIS (Netherlands)

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


    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 be

  9. Bank stability analysis for fluvial erosion and mass failure (United States)

    The central objective of this study was to highlight the differences in magnitude between mechanical and fluvial streambank erosional strength with the purpose of developing a more comprehensive bank stability analysis. Mechanical erosion and ultimately failure signifies the general movement or coll...

  10. Usefulness of Ω-shaped Incision in Skin Tumor Excision

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    Naoshige Iida, MD, PhD


    Full Text Available Summary: We devised the Ω-shaped incision as a technique for skin tumor resection on the areas of skin with an arc-shaped fold. With this technique, the dog-ear that is formed during 6 wound closure can be resected within the range of the first skin incision. We report this technique after performing it on the face or trunk of 18 patients and confirmed its usefulness.

  11. Hydrological and sedimentological regime of lower Vistula fluvial lakes (North Central Poland) (United States)

    Kordowski, Jarosław; Kubiak-Wójcicka, Katarzyna; Tyszkowski, Sebastian; Solarczyk, Adam


    Regarding the outflow the Vistula River is the largest river in the Baltic catchment. In its lower course it has developed an anastomosing channel pattern modified strongly by intensive human hydrotechnical activity and by the regulation which have intensified about 200 years ago. Channel regulation apart from already existing lakes have left many new artificially created ones. This activity have also altered the hydrological and sedimentary regime. It turned out that only the small portion of the lakes infilled rapidly but the majority have persisted to present day almost unchanged in spite of regulation. The reason of this resistence to silting is connected with specific interaction of sediment removing during high flood water episodes and strong groundwater circulation in former river arms transformed in present-day lakes. As an example of a lake with an intensive groundwater exchange rate with the main Vistula channel and supposed Quaternary and Tertiary aquifers was selected the Old Vistula lake (Stara Wisła) near Grudziądz town. It has got an area of 50 ha, mean depth 1,73 m, maximum depth 8 m, length about 4 km and medium width about 100 m. In the years 2011-2015 in its surficial water were conducted measures with two weeks frequency which included: temperature, pH, Eh, suspended matter amount, total and carbonaceous mineralization. For comparison similar measurements were also conducted in other fluvial lakes and Vistula tributaries. Hydrological data were supplemented by geological investigations of floodplain sediments cover which has important impact on the rate of groundwater migration and circulation. Investigations carried proved that there exists distinct gradient of carbonaceous mineralization from small values in the Vistula channel to high values at the valley edges. PH and Eh parameters in the Old Vistula lake were different than in all other surveyed sites what leads to conclusion that it is fed by deeper groundwaters than in the case of other

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

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    Erkens, G.


    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

  13. The Fluvial Archives Group: 20 years of research connecting fluvial geomorphology and palaeoenvironments (United States)

    Cordier, Stéphane; Briant, Becky; Bridgland, David; Herget, Jürgen; Maddy, Darrel; Mather, Anne; Vandenberghe, Jef


    The Fluvial Archives Group (FLAG) was formed in 1996 under the auspices of the British Quaternary Research Association (QRA). The rationale for its creation was the desire to bring together those working across timescales encompassing the last few million years to the Holocene and even modern process studies. The principles of uniformitarianism are important in the validation of this grouping of interests, with the modern and recent providing analogues from which the older and longer-timescale sequences can be more readily interpreted. The creation of FLAG occurred in the context of improved understanding of terrestrially-based Quaternary sequences and at a time when knowledge of the environmental significance of river systems had also seen great advances, following several decades of engineering experience and research into the management of such systems. This field was subsequently transformed in the European Union by the Water Framework Directive (WFD, 2000), which promoted a strategy for the re-naturalization of rivers. Above all, the WFD implied the (re-)establishment of an initial, pre-anthropogenic, reference state, the recovery of which was a prime aim. This would be a demanding task, considering that rivers are characterized by constant change, even without anthropogenic intervention. The evidence for and understanding of such change, observable at various timescales, is very much the business of FLAG (see below, section 6).

  14. Fluvial signatures of modern and paleo orographic rainfall gradients (United States)

    Schildgen, Taylor; Strecker, Manfred


    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.

  15. A mineral magnetic characterization of the Plio-Pleistocene fluvial infill of the Heidelberg Basin (Germany) (United States)

    Scheidt, Stephanie; Egli, Ramon; Frederichs, Thomas; Hambach, Ulrich; Rolf, Christian


    The Heidelberg Basin (Germany) hosts a quasi-continuous sedimentary sequence of primarily fluvial sediments with pedogenetic overprints and lacustrine intercalations. This unconsolidated succession has been shown to record a consistent magnetic polarity stratigraphy of the Quaternary and the late Neogene. Previous work has reported that sulphides and high-coercive minerals are the carriers of the remanent magnetization. Here, we provide the results of an extended mineral magnetic study that aims to disentangle the complex magnetic mineralogy. In addition, we assess the reliability of these minerals as carriers of palaeomagnetic signals. A major obstacle to the analysis of the drill cores was the large number of samples that were taken from a total core length of 1150 m. Rapid measurements on bulk samples provided only limited information on the magnetic mineralogy. In contrast, time-intensive methods such as first-order reversal curves (FORCs) or coercivity analyses, for example, yielded valuable information. The combined results of all the analyses consider the heterogeneous compositions of the sediments and indicate a varying palaeoenvironmental history. The Pliocene Iffezheim Formation was formed under alternating reducing and oxidizing conditions. Magnetite, maghemite, haematite and goethite are the predominant magnetic minerals. Sulphides were only preserved under specific conditions. The Pleistocene sediments reflect predominantly reducing conditions during sedimentation and diagenesis. Greigite, pyrite and most likely pyrrhotite have been shown to occur. Taken together, our work provides a detailed environmental magnetic record of the Plio-Pleistocene and elucidates the capabilities and limitations of rock magnetic studies performed on fluvial dominated sedimentary successions.

  16. Multidecadal Fluvial Sediment Fluxes to Deltas under Environmental Change Scenarios (United States)

    Dunn, Frances; Darby, Stephen; Nicholls, Robert


    Sediment delivery is vital to sustain delta environments on which over half a billion people live worldwide. Due to factors such as subsidence and sea level rise, deltas sink relative to sea level if sediment is not delivered to and retained on their surfaces. Deltas which sink relative to sea level experience flooding, land degradation and loss, which endangers anthropogenic activities and populations. The future of fluvial sediment fluxes, a key mechanism for sediment delivery to deltas, is uncertain due to complex environmental changes which are predicted to occur over the coming decades. This research investigates fluvial sediment fluxes under environmental changes in order to assess the sustainability of delta environments under potential future scenarios up to 2100. Global datasets of climate change, reservoir construction, and population and GDP as proxies for anthropogenic influence through land use changes are used to drive the catchment numerical model WBMsed, which is being used to investigate the effects of these environmental changes on fluvial sediment delivery. This process produces fluvial sediment fluxes under multiple future scenarios which will be used to assess the future sustainability of a selection of 8 vulnerable deltas, although the approach can be applied to deltas worldwide. By modelling potential future scenarios of fluvial sediment flux, this research contributes to the prognosis for delta environments. The future scenarios will inform management at multiple temporal scales, and indicate the potential consequences for deltas of various anthropogenic activities. This research will both forewarn managers of potentially unsustainable deltas and indicate those anthropogenic activities which encourage or hinder the creation of sustainable delta environments.

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

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    Yongqi He


    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.

  18. Rapid Gorge Formation in an Artificially Created Waterfall (United States)

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


    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.

  19. How to find the sedimentary archive of fluvial pollution in a bedrock-confined river reach (United States)

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


    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

  20. Geometry of the Paleo-Nueces River Incised-Valley, Corpus Christi Bay, Texas as it Relates to Quaternary Sea Level History (United States)

    Lugrin, L.; Gulick, S. S.; Goff, J. A.


    CHIRP subbottom seismic data were collected on the 2009 and 2011 Marine Geophysics Field courses at the University of Texas at Austin within the Corpus Christi Bay along the central Texas coast in order to study the geometry of the ancestral Nueces River incised valley and its evolution over Quaternary sea level history. Since the late Pleistocene, the Nueces River valley experienced a gradual infill due to sea level rise, interrupted by two major flooding events that represent periods of rapid sediment influx. These flooding events are recognizable based on abrupt changes in seismic facies. Discontinuous, chaotic fluvial lag deposits present underneath a fairly continuous, stratified, sub-horizontal estuarine coastal plain facies mark what is interpreted to be the Pleistocene/Holocene unconformity. Above the P/H boundary, oyster reefs thrive within the estuary until capped by a strong reflector, marking the second flooding surface that allowed enough incoming sediment to discontinue oyster reef growth. The estuarine deposits within the paleo-Nueces river valley exhibit a landward migration as the Holocene transgression proceeded. As infill continued, the bay-head delta prograded seaward and the flood-tidal delta extended progressively further up the estuary until the central estuarine basin was capped. The earlier flooding events provide strong reflectors that can be linked to the draining of Lake Agassiz around 8.2 k.a.. This event flooded the Gulf of Mexico with freshwater, and interrupted the estuarine infilling of the Nueces paleo-channel. Cores from previous studies have found at least two species of oyster reefs in Corpus Christi Bay: euryhaline species Crassostrea virginica, and Ostrea equestris, a species known to thrive in higher salinity waters. The presence of both species at the flooding boundary suggests the sudden pulse of freshwater mixed with higher salinity oceanic water. The second flooding surface is interpreted to be associated with an increase

  1. Ultrasonic incisions produce less inflammatory mediator response during early healing than electrosurgical incisions.

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    Bindu Nanduri

    Full Text Available As the use of laparoscopic surgery has become more widespread in recent years, the need has increased for minimally-invasive surgical devices that effectively cut and coagulate tissue with reduced tissue trauma. Although electrosurgery (ES has been used for many generations, newly-developed ultrasonic devices (HARMONIC® Blade, HB have been shown at a macroscopic level to offer better coagulation with less thermally-induced tissue damage. We sought to understand the differences between ES and HB at a microscopic level by comparing mRNA transcript and protein responses at the 3-day timepoint to incisions made by the devices in subcutaneous fat tissue in a porcine model. Samples were also assessed via histological examination. ES-incised tissue had more than twice as many differentially-expressed genes as HB (2,548 vs 1,264 respectively, and more differentially-expressed proteins (508 vs 432 compared to control (untreated tissue. Evaluation of molecular functions using Gene Ontology showed that gene expression changes for the energized devices reflected the start of wound healing, including immune response and inflammation, while protein expression showed a slightly earlier stage, with some remnants of hemostasis. For both transcripts and proteins, ES exhibited a greater response than HB, especially in inflammatory mediators. These findings were in qualitative agreement with histological results. This study has shown that transcriptomics and proteomics can monitor the wound healing response following surgery and can differentiate between surgical devices. In agreement with clinical observations, electrosurgery was shown to incur a greater inflammatory immune response than an ultrasonic device during initial iatrogenic wound healing.

  2. Post-glacial rock avalanche causing epigenetic gorge incision (Strassberg gorge, Eastern Alps). (United States)

    Sanders, Diethard


    In the western part of the Eastern Alps, the Strassberg gorge 1.5 km in length and down to 100 m in depth shows a marked asymmetry in height of its right/left brinklines. The gorge is incised into Upper Triassic dolostones, and parallels an older valley filled with Quaternary deposits. Upstream, the valley-fill consists of (a) glacial till (Last Glacial Maximum, LGM), overlain by (b) a rock avalanche deposit (RAD) at least a few tens of meters thick, and (c) alluvial deposits shed over the RAD (except for projecting boulders); the RAD is locally also downlapped by scree slopes. Downstream, the valley-fill consists of glacio-fluvial deposits overlain by LGM till and, on top, the RAD. The rock avalanche defaced from the west slope of mount Hohe Munde (2662 m asl), and consists exclusively of clasts of Wetterstein Limestone (Triassic p. p.). Rock avalanche defacement was tied to a system of NW-SE trending strike-slip faults (Telfs fault zone). The rock avalanche descended before the old valley was significantly cleared of glaciofluvial/glacial deposits of the LGM. On a plateau west of the present bedrock gorge, LGM till is veneered over a large area by RAD; the till and the RAD both were later involved in slumping. The RAD covers a total planview area of ~3.7 square kilometers. The fahrböschung of the rock avalanche is reconstructed between 16°-14.5°. In its proximal part, the rock avalanche propagated by dynamic fragmentation; in the distal part, propagation was by sheet-like 'plug flow', perhaps in part over a snow cover. The filling of the old valley by the RAD led to: (a) formation and filling of a small intramontane basin directly upstream, and (b) incision of the present Strassberg gorge along a course westward-parallel to the old valley. Mean rates of bedrock incision required to form the deepest reach of the present canyon range from 1 cm/a (since 10 ka) to 0.7 cm/a (since 15 ka). In the considered area, talus breccias of pre-LGM age locally show zones of

  3. Expading fluvial remote sensing to the riverscape: Mapping depth and grain size on the Merced River, California (United States)

    Richardson, Ryan T.

    This study builds upon recent research in the field of fluvial remote sensing by applying techniques for mapping physical attributes of rivers. Depth, velocity, and grain size are primary controls on the types of habitat present in fluvial ecosystems. This thesis focuses on expanding fluvial remote sensing to larger spatial extents and sub-meter resolutions, which will increase our ability to capture the spatial heterogeneity of habitat at a resolution relevant to individual salmonids and an extent relevant to species. This thesis consists of two chapters, one focusing on expanding the spatial extent over which depth can be mapped using Optimal Band Ratio Analysis (OBRA) and the other developing general relations for mapping grain size from three-dimensional topographic point clouds. The two chapters are independent but connected by the overarching goal of providing scientists and managers more useful tools for quantifying the amount and quality of salmonid habitat via remote sensing. The OBRA chapter highlights the true power of remote sensing to map depths from hyperspectral images as a central component of watershed scale analysis, while also acknowledging the great challenges involved with increasing spatial extent. The grain size mapping chapter establishes the first general relations for mapping grain size from roughness using point clouds. These relations will significantly reduce the time needed in the field by eliminating the need for independent measurements of grain size for calibrating the roughness-grain size relationship and thus making grain size mapping with SFM more cost effective for river restoration and monitoring. More data from future studies are needed to refine these relations and establish their validity and generality. In conclusion, this study adds to the rapidly growing field of fluvial remote sensing and could facilitate river research and restoration.

  4. Climate-driven sediment aggradation and incision phases since the Late Pleistocene in the NW Himalaya, India (United States)

    Dey, Saptarshi; Thiede, Rasmus C.; Schildgen, Taylor F.; Wittmann, Hella; Bookhagen, Bodo; Scherler, Dirk; Jain, Vikrant; Strecker, Manfred R.


    Deciphering the response of sediment routing systems to climatic forcing is fundamental for understanding the impacts of climate change on landscape evolution and depositional systems. In the Sub-Himalaya, late Pleistocene to Holocene alluvial fills and fluvial terraces record periodic fluctuations of sediment supply and transport capacity on timescale of 103 to 105 years, most likely related to past climatic fluctuations. To evaluate the climatic control on sediment supply and transport capacity, we analyze remnant alluvial fans and terraces in the Kangra Basin of the northwestern Sub-Himalaya. Based on field observations and OSL and CRN-dating, we recognized two sedimentary cycles with major sediment aggradation and subsequent re-incision phases. The large one developed over the entire last glacial period with ˜200 m high alluvial fan (AF1) and the second one during the latest Pleistocene/Holocene with ˜50 m alluvial fan (AF2) and its re-incision . Surface-exposure dating of six terrace levels with in-situ cosmogenic nuclides (10Be) indicates the onset of channel abandonment and ensuing incision phases. Two terrace surfaces from the highest level (T1) sculpted into the oldest-preserved AF1 dates back to 48.9 ± 4.1 ka and 42.1 ± 2.7 ka (2σ error). T2 surfaces sculpted into the remnants of AF1 have exposure ages of 16.8 ± 2 ka and 14.1 ± 0.9 ka, while terraces sculpted into the late Pleistocene- Holocene fan (AF2) provide ages of 8.4± 0.8 ka, 6.6± 0.7 ka, 4.9± 0.4 ka and 3.1± 0.3 ka. Together with previously-published ages on the timing of aggradation, we find a correlation between variations in sediment transport with oxygen-isotope records from regions affected by Indian Summer Monsoon. During stronger monsoon phases and post-LGM glacial retreat manifested by increased sediment delivery (moraines and hillslope-derived) to the trunk streams, causing aggradation in the basin; whereas, weakened monsoon phases characterized by reduced sediment

  5. Morphine reduces local cytokine expression and neutrophil infiltration after incision

    Directory of Open Access Journals (Sweden)

    Li Xiangqi


    Full Text Available Abstract Background Inflammation and nociceptive sensitization are hallmarks of tissue surrounding surgical incisions. Recent studies demonstrate that several cytokines may participate in the enhancement of nociception near these wounds. Since opioids like morphine interact with neutrophils and other immunocytes, it is possible that morphine exerts some of its antinociceptive action after surgical incision by altering the vigor of the inflammatory response. On the other hand, keratinocytes also express opioid receptors and have the capacity to produce cytokines after injury. Our studies were directed towards determining if opioids alter cytokine production near incisions and to identify cell populations responsible for producing these cytokines. Results A murine incisional model was used to measure the effects of acute morphine administration (0.1–10 mg/kg on nociceptive thresholds, neutrophil infiltration and cytokine production in hind paw skin 30 minutes and 2 hours after incision. Incised hind paws displayed profound allodynia which was reduced by morphine (0.1–10 mg/kg in the 2 hours following incision. Skin samples harvested from these mice showed enhanced levels of 5 cytokines: IL-1β, IL-6, tumor necrosis factor alpha (TNFα, granulocyte colony stimulating factor (G-CSF and keratinocyte-derived cytokine (KC. Morphine reduced these incision-stimulated levels. Separate analyses measuring myeloperoxidase (MPO and using immunohistochemistry demonstrated that morphine dose-dependently reduced the infiltration of neutrophils into the peri-incisional tissue. The dose of morphine required for reduction of cytokine accumulation, however, was below that required for inhibition of peri-incisional neutrophil infiltration. Additional immunohistochemical studies revealed wound edge keratinocytes as being an important source of cytokines in the acute phase after incision. Conclusion Acute morphine administration of doses as low as 0.1 mg/kg reduces

  6. Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River (United States)

    Gran, K. B.


    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

  7. Relationship of Incisive Papilla to Maxillary Incisors and Canines. (United States)

    Shrestha, Suraksha; Joshi, Sarita Pradhan; Yadav, Santosh Kumar


    The study was carried to find a relationship between the postextraction stable landmark, the incisive papilla, and the most labial position of the maxillary central incisor teeth, which occurred in Nepalese population. Casts of the subjects selected by nonprobability random sampling meeting the inclusion criteria were obtained. Each casts were standardized with respect to the occlusal plane and a photographic technique was used to measure the distance from the tangent of the labial surface of the central incisors to the posterior border of the incisive papilla. The measurements were made using Adobe Photoshop and results were analyzed by using appropriate statistical methods. Most appropriate software (SPSS) for the purpose was used to generate all desired values. The data obtained suggested that the distance from the labial surface of maxillary central incisors to the posterior border of the incisive papilla ranged from 9 to 15.9 mm with a mean of 11.59 mm (SD 1.3). Various other results were also found after evaluation of the arch forms in relation to sex and race. Within the limitations of the study, these results suggested that there is a relationship between the maxillary central incisors and the incisive papilla aiding in the anteroposterior positioning of the anterior tooth. The clinical relevance of the study lies in application of the incisive papilla as a starting point in the preliminary location of maxillary incisors and canines during construction of the denture in absence of preextraction records.

  8. Slide crown lengthening procedure using wide surface incisions and cyanoacrylate. (United States)

    Szymaitis, Dennis W


    This article introduces the slide crown lengthening procedure (SCLP), which incorporates surgical design features to overcome present crown lengthening procedure (CLP) shortcomings. The result is a 75% decrease in required surgery on adjacent teeth and a corresponding 75% reduction in surgical time. Other advantages include a reduction in surgical morbidity, improvement in terminal esthetics, and fewer teeth subject to papillae removal and apically repositioned gingiva. The 20 to 30 degree incision forming the slide is the pivotal feature; it allows effortless flap positioning. This incision angle enables wide surface incisions to adhere flaps together by producing stronger fibrin clots, decreasing tissue retraction angles, and reforming disrupted fibrin clots as incision sides slide while maintaining contact. This enhanced fibrin clot eliminates the need for sutures. The slide produced by the 20 to 30 degree incision functions for crown lengthening on all sites (facial, lingual, or palatal). This versatile surgical design introduces a new healing dimension that adapts to and provides benefits for other dental surgeries, such as gingival grafts, endodontic surgery, implants, and extractions.


    Institute of Scientific and Technical Information of China (English)


    To research into the problem of degradation and fluvial process downstream reservoirs and its influence on flood control and navigation, a 1-D mathematical model of degradation and fluvial process downstream the reservoir was established in this paper. The non-equilibrium transport of non-uniform suspended load, the non-uniform bedload transport and bed material sorting were considered in the model. Some techniques were suggested for some problems in calculation, such as the effective suspended load carrying capacity of the different reaches of bed materials, the coefficient of suspended load carrying capacity, the recovering coefficient of carrying capacity, the mixed layer thickness, the bedload transport width, bifurcation and confluence of main and branch channel, and the distribution of deposition and erosion along the cross section, etc. The model was tested by the data of degradation downstream the Danjiangkou reservoir on the Hanjiang River and the data of degradation downstream the Gezhouba Project on the Yangtze River.

  10. 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


    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.

  11. From archive to process in past fluvial systems (United States)

    Dikau, R.


    The reconstruction of sediment fluxes through palaeo ecological systems is based on effect (sediment record) - cause (soil erosion, fluvial transport, sediment deposition) relationships using abduction as central methodology. In philosophy of science abduction means, that the effect of a palaeo process is known. e.g. a recent sediment body including specific properties of this archive. There are, however, potentially a range of laws that could be applied to explain the cause, e.g. a human or a climatic impact or internal system behaviour. From a methodological point of view this means that the coupling of cause and effect has to consider several potential starting points of the sediment flux system and a range of laws or explanations which increases the degree of uncertainty significantly. Particularly in modelling plaeo sediment flux systems no reliable transfer functions exist which translate sediment archive properties into flux processes. This general methodological challenge for reconstructing palaeo systems is a particular problem in fluvial systems. Fluvial systems act as a filter whose properties for past time scales are widely unknown. This represents a decoupled cause-effect relationship. The filter function of these system types means, that the external signal that drives the sediment flux record cannot be read directly from that record and that e.g. climatic hypotheses eventually are not testable. The methodology to link archive and process therefore requires spatially-structured storage and release models including abductive interpretation laws for internal feedbacks, thresholds and complex non-linear dynamics. Based on these arguments the aim this presentation is a discussion of a methodological framework in past fluvial system understanding.

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

    Directory of Open Access Journals (Sweden)

    Tetsushi Aizawa, MD


    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.

  13. Time between skin incision and delivery during cesarean. (United States)

    Rossouw, Jana N; Hall, David; Harvey, Justin


    To investigate factors influencing skin incision-to-delivery time (including sub-divisions thereof) and the effect of these surgical intervals on immediate neonatal outcome. A prospective cohort analysis was conducted of all women undergoing cesarean delivery at Tygerberg Hospital, Cape Town, South Africa, from May 24 to November 2, 2010. Three surgical intervals were evaluated: skin incision to myometrium, myometrium to delivery, and skin incision to delivery. Neonatal outcome was assessed by the 5-minute Apgar score. Of 1120 cesarean deliveries recorded during the study period, 77.2% were emergency procedures, which were performed more quickly at all surgical planes (Pdelivery time was significantly extended among repeat procedures (Pdeliveries. Repeat procedures, adhesions, and obesity prolonged the time taken for cesarean delivery. Nevertheless, the effect of these factors on the 5-minute Apgar score was minimal. Copyright © 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.


    Institute of Scientific and Technical Information of China (English)

    刘宝国; 王成学; 张乃嵩


    Objective: To report the development of a technique for minimally invasive thyroid lobectomy. Method: The procedure was accepted by 200 patients with a nodule of the lobe of the thyroid. We performed hemithyroidectomys through a 2-4 cm low-collar horizontal skin incision by conventional instrumentation. Results: The recurrent laryngeal nerve and the parathyroid glands were easily identified and preserved. The amount of bleeding ranged from 5 to 50 ml (mean 15 ml). Mean Operation time was 52.2 minutes (ranged 32 to 80 minutes). No complication occurred. Mean postoperative stay was 5.5 days (ranged 4 to 7 days). The incision provided excellent cometic results because the small and lower incisions were completely hidden by clothing collar. Conclusion: The above technique is feasible, safe, minimally invasive, less time and cost consuming and cosmetical.

  15. Sharp compared with blunt fascial incision at cesarean delivery

    DEFF Research Database (Denmark)

    Aabakke, Anna J M; Hare, Kristine J; Krebs, Lone


    OBJECTIVE: To compare patient preference for either sharp incision with scissors or blunt manual cleavage of the fascia at cesarean delivery in a randomized controlled trial in which each woman was her own control. STUDY DESIGN: Women undergoing primary cesarean delivery (n=34) were randomized...... to side distribution of sharp or blunt incision of the fascia (sharp right and blunt left or blunt right and sharp left) and followed three months postoperatively. The primary outcome was patient preference for the right or left side of the scar 3 months postoperatively and modeled by polytomous logistic...... difference was found in patient preference with regard to sharp or blunt incision of the fascia, nor was there a significant difference in postoperative pain scores. CLINICAL TRIAL REGISTRATION:;NCT01297725....

  16. Transient Fluvial Response to Alpine Deglaciation, Mount Rainier, WA: Geomorphic Process Domains and Proglacial Flux Controls on Channel Evolution. (United States)

    Beyeler, J. D.; Montgomery, D.; Kennard, P. M.


    Downwasting of all glaciers on the flanks of Mount Rainier, WA, in recent decades has debuttressed Little Ice Age glaciogenic sediments driving proglacial responses to regionally warming climate. Rivers draining the deglaciating edifice are responding to paraglacial sedimentation processes through transient storage of retreat-liberated sediments in aggrading (e.g., >5m) fluvial networks with widening channel corridors (i.e., 50-150%) post-LIA (ca., 1880-1910 locally). We hypothesize that the downstream transmission of proglacial fluxes (i.e., sediment and water) through deglaciating alpine terrain is a two-step geomorphic process. The ice-proximal portion of the proglacial system is dominated by the delivery of high sediment-to-water ratio flows (i.e., hyperconcentrated and debris slurries) and sediment retention by in-channel accumulation (e.g., confined debris fans within channel margins of valley segments) exacerbated by recruitment and accumulation of large wood (e.g., late seral stage conifers), whereas ice-distal fluvial reworking of transient sediment accumulations generates downstream aggradation. Historical Carbon River observations show restricted ice-proximal proglacial aggradation until a mainstem avulsion in 2009 initiated incision into sediment accumulations formed in recent decades, which is translating into aggradation farther down the network. Surficial morphology mapped with GPS, exposed subsurface sedimentology, and preliminary dating of buried trees suggest a transitional geomorphic process zone has persisted along the proglacial Carbon River through recent centuries and prior to the ultimate LIA glaciation. Structure-from-motion DEM differencing through the 2016 water year shows discrete zones of proglacial evolution through channel-spanning bed aggradation forced by interactions between large wood and sediment-rich flows that transition to fluvial process dominance as sediment is transported downstream. Long-term DEM differencing suggests

  17. Single-incision laparoscopy surgery: a systematic review (United States)

    far, Sasan Saeed; Miraj, Sepide


    Background Laparoscopic surgery is a modern surgical technique in which operations are performed far from their location through small incisions elsewhere in the body. Objective This systematic review is aimed to overview single-incision laparoscopy surgery. Methods This systematic review was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified about 87 references. In this study, 54 studies were accepted for further screening and met all our inclusion criteria [in English, full text, therapeutic effects of single-incision laparoscopy surgery and dated mainly from the year 1990 to 2016]. The search terms were “single-incision,” “surgery,” and “laparoscopy.” Results Single-incision laparoscopy surgery is widely used for surgical operations in cholecystectomy, sleeve gastrectomy, cholecystoduodenostomy, hepatobiliary disease, colon cancer, obesity, appendectomy, liver surgery, rectosigmoid cancer, vaginal hysterectomy, vaginoplasty, colorectal lung metastases, pyloroplasty, endoscopic surgery, hernia repair, nephrectomy, rectal cancer, colectomy and uterus-preserving repair, bile duct exploration, ileo-ileal resection, lymphadenectomy, incarcerated inguinal hernia, anastomosis, congenital anomaly, colectomy for cancer. Conclusion Based on the findings, single-incision laparoscopy surgery is a scarless surgery with minimal access. Although it possesses lots of benefits, including less incisional pain and scars, cosmesis, and the ability to convert to standard multiport laparoscopic surgery, it has some disadvantages, for example, less freedom of movement, fewer number of ports that can be used, and the proximity of the instruments to each other during the operation. PMID:27957308

  18. Two decades of numerical modelling to understand long term fluvial archives: Advances and future perspectives (United States)

    Veldkamp, A.; Baartman, J. E. M.; Coulthard, T. J.; Maddy, D.; Schoorl, J. M.; Storms, J. E. A.; Temme, A. J. A. M.; van Balen, R.; van De Wiel, M. J.; van Gorp, W.; Viveen, W.; Westaway, R.; Whittaker, A. C.


    The development and application of numerical models to investigate fluvial sedimentary archives has increased during the last decades resulting in a sustained growth in the number of scientific publications with keywords, 'fluvial models', 'fluvial process models' and 'fluvial numerical models'. In this context we compile and review the current contributions of numerical modelling to the understanding of fluvial archives. In particular, recent advances, current limitations, previous unexpected results and future perspectives are all discussed. Numerical modelling efforts have demonstrated that fluvial systems can display non-linear behaviour with often unexpected dynamics causing significant delay, amplification, attenuation or blurring of externally controlled signals in their simulated record. Numerical simulations have also demonstrated that fluvial records can be generated by intrinsic dynamics without any change in external controls. Many other model applications demonstrate that fluvial archives, specifically of large fluvial systems, can be convincingly simulated as a function of the interplay of (palaeo) landscape properties and extrinsic climate, base level and crustal controls. All discussed models can, after some calibration, produce believable matches with real world systems suggesting that equifinality - where a given end state can be reached through many different pathways starting from different initial conditions and physical assumptions - plays an important role in fluvial records and their modelling. The overall future challenge lies in the development of new methodologies for a more independent validation of system dynamics and research strategies that allow the separation of intrinsic and extrinsic record signals using combined fieldwork and modelling.

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


    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.

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

    LENUS (Irish Health Repository)

    Ahmad, Nasir Zaheer


    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. Monitoring fluvial erosion of the Oso landslide, Washington, using repeat Structure-from-Motion photogrammetry (United States)

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


    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

  2. The Association of Anastomosed fluvial deposits and dinosaur tracks, eggs, and nests: Implications for the interpretation of floodplain environments and a possible survival strategy for ornithopods

    Energy Technology Data Exchange (ETDEWEB)

    Nadon, G.C. (Univ. of Wisconsin, Madison (United States))


    The St. Mary River Formation (Maastrichtian) consists of anastomosed fluvial deposits containing several hundred track-bearing beds. Paleontologic and sedimentologic analyses of these beds indicate that large herbivores, ornithopods, inhabited a seasonal wetland dominated by marshes and lakes. Shallow tracks in fine-grained sediments, formed as the sediments dewatered to the point of stiffness, display the highest resolution of detail. The preservation potential of tracks in anastomosed fluvial deposits is large because of the abundance of soft substrates to record the tracks and the occurrence of annual flooding to rapidly bury the footprints. Comparison of the St. Mary River Formation to other anastomosed fluvial deposits as old as the Early Jurassic confirms that tracks are common in this type of deposit. The variation in preservation of track types and depth of penetration raises the possibility that ornithopods employed a survival strategy involving seasonal wetlands. The wetlands provided an abundant food source and at the same time the combination of a soft substrate and flooded conditions would have effectively countered the superior speed and agility of large carnivores. The relatively common occurrence of ornithopod eggshells from anastomosed fluvial deposits suggests that the abundant food supply accompanying the wet season also made the wetlands an ideal location to rear young. These data can be used to refine the interpretations of depositional environment derived from the sediments by allowing estimates to be made regarding the early post-depositional conditions of the sediments. 95 refs., 7 figs., 1 tab.

  3. A manual to identify sources of fluvial sediment (United States)

    Gellis, Allen; Fitzpatrick, Faith; Schubauer-Berigan, Joseph


    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.


    Directory of Open Access Journals (Sweden)

    Haridarshan Sira


    Full Text Available BACKGROUND Laparoscopic surgery has undergone several modifications since its advent. There has been a shift from a standard multiport approach to more minimalistic approaches. SILS is a major step in this evolutionary process. We present our experience with SILS using conventional laparoscopic instruments and without the need for a SILS port. METHODS 211 patients in Fortis Hospitals, Bangalore, India, who underwent SILS for various abdominal conditions from May 2009 to May 2011 were included in the study. Variables such as operating time, conversion to multi-port laparoscopy or open surgery, complications, analgesia requirements and hospital stay were included. RESULTS 211 patients underwent SILS using conventional laparoscopic instruments for Gallstones, Appendicitis, Morbid Obesity, Gynaecological conditions and Renal cysts. Average age group was 48.5 years; mean duration of hospital stay was 46.5 hours; 166 Laparoscopic cholecystectomies were done, out of which 47 were acute cholecystitis. There were no cases converted to open surgeries. CONCLUSION Single Incision Laparoscopic surgery is technically feasible and as effective as conventional laparoscopic surgery. It is a safe procedure and provides an advantage with regards to analgesia requirement, length of hospital stay and early return to work. Cosmetically, it is superior to multiport laparoscopy.

  5. Response of a dryland fluvial system to climate–tectonic perturbations during the Late Quaternary: Evidence from Rukmawati River basin, Kachchh, western India

    Indian Academy of Sciences (India)

    Archana Das; Falguni Bhattacharya; B K Rastogi; Gaurav Chauhan; Mamata Ngangom; M G Thakkar


    Dryland rivers, dominated by short-lived, localised and highly variable flow due to discrete precipitation events, have characteristic preservation potential, which serves as suitable archives towards understanding the climate–tectonic coupling. In the present study, we have investigated the fluvial records of a major, southerly-draining river – the Rukmawati River in the dryland terrain of southern Kachchh, in western India. The sediment records along the bedrock rivers of Kachchh register imprints of the Indian summer monsoon (ISM), which is the major source of moisture to the fluvial system in western India. The Rukmawati River originates from the Katrol Hill Range in the north and flows towards the south, into the Gulf of Kachchh. The field stratigraphy, sedimentology, along with the optical chronology suggeststhat a braided-meandering system existed during 37 ka period due to an overall strengthened monsoon. A gradual decline in the monsoon strength with fluctuation facilitated the development of a braided channel system between 20 and 15 ka. A renewed phase of strengthened monsoon with seasonality after around 15 ka which persisted until around 11 ka, is implicated in the development of floodplain sequences. Two zones of relatively high bedrock uplift are identified based on the geomorphometry and morphology of the fluvial landform. These zones are located in the vicinity of the North Katrol Hill Fault (NKHF) and South Katrol Hill Fault (SKHF). Geomorphic expression of high bedrock uplift is manifested by the development of beveled bedrock prior to or around 20 ka during weak monsoon. The study suggests that the terrain in the vicinity of NKHF and SKHF is uplifting at around 0.8 and >0.3 mm/a, respectively. Simultaneously, the incision in the Rukmawati River basin, post 11 ka, is ascribed to have occurred due to lowered sea level during the LGM and early Holocene period.

  6. Response of a dryland fluvial system to climate-tectonic perturbations during the Late Quaternary: Evidence from Rukmawati River basin, Kachchh, western India (United States)

    Das, Archana; Bhattacharya, Falguni; Rastogi, B. K.; Chauhan, Gaurav; Ngangom, Mamata; Thakkar, M. G.


    Dryland rivers, dominated by short-lived, localised and highly variable flow due to discrete precipitation events, have characteristic preservation potential, which serves as suitable archives towards understanding the climate-tectonic coupling. In the present study, we have investigated the fluvial records of a major, southerly-draining river - the Rukmawati River in the dryland terrain of southern Kachchh, in western India. The sediment records along the bedrock rivers of Kachchh register imprints of the Indian summer monsoon (ISM), which is the major source of moisture to the fluvial system in western India. The Rukmawati River originates from the Katrol Hill Range in the north and flows towards the south, into the Gulf of Kachchh. The field stratigraphy, sedimentology, along with the optical chronology suggests that a braided-meandering system existed during 37 ka period due to an overall strengthened monsoon. A gradual decline in the monsoon strength with fluctuation facilitated the development of a braided channel system between 20 and 15 ka. A renewed phase of strengthened monsoon with seasonality after around 15 ka which persisted until around 11 ka, is implicated in the development of floodplain sequences. Two zones of relatively high bedrock uplift are identified based on the geomorphometry and morphology of the fluvial landform. These zones are located in the vicinity of the North Katrol Hill Fault (NKHF) and South Katrol Hill Fault (SKHF). Geomorphic expression of high bedrock uplift is manifested by the development of beveled bedrock prior to or around 20 ka during weak monsoon. The study suggests that the terrain in the vicinity of NKHF and SKHF is uplifting at around 0.8 and >0.3 mm/a, respectively. Simultaneously, the incision in the Rukmawati River basin, post 11 ka, is ascribed to have occurred due to lowered sea level during the LGM and early Holocene period.

  7. Fluvial landscape development in the southwestern Kalahari during the Holocene - Chronology and provenance of fluvial deposits in the Molopo Canyon (United States)

    Ramisch, Arne; Bens, Oliver; Buylaert, Jan-Pieter; Eden, Marie; Heine, Klaus; Hürkamp, Kerstin; Schwindt, Daniel; Völkel, Jörg


    The southern Kalahari drainage network is in a key position to analyze spatiotemporal changes in the tropical easterly and the temperate westerly circulation over the Southern African subcontinent. However, due to the prevailing aridity, paleoenvironmental archives within the southwestern Kalahari 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 perennial flow regime of the Orange River. To gain insight into temporal aspects of fluvial morphodynamics within the Molopo Canyon, the entire variety of fluvial landforms consisting mainly of slope sediments, alluvial fans and alluvial fills were dated using Optically Stimulated Luminescence (OSL). We additionally applied a provenance analysis on alluvial fill deposits to estimate potential sediment source areas. Source areas were identified by analyzing the elemental and mineralogical composition of tributaries and eolian deposits throughout the course of the lower Molopo. The results allow the first general classification of fluvial landscape development into three temporally distinct deposition phases in the southern Kalahari: (1) A phase of canyon aggradation associated with short lived and spatially restricted flash floods during the early to mid-Holocene; (2) a phase of fan aggradation indicating a decrease in flood intensities during the mid- to late Holocene; and (3) a phase of canyon aggradation caused by the occurrence of supra-regional flood events during the Little Ice Age. We interpret the observed spatiotemporal deposition patterns to latitudinal shifts of the tropical easterly circulation in the early to mid-Holocene and the temperate westerly circulation in the late Holocene. However, despite marked changes in the provenance and timing of fluvial

  8. Developing an Understanding of Vegetation Change and Fluvial Carbon Fluxes in Semi-Arid Environments (United States)

    Puttock, A.; Brazier, R. E.; Dungait, J. A. J.; Bol, R.; Macleod, C. J. A.


    biogeochemical techniques, using stable 13C isotope and lipid biomarker analyses, to trace and partition fluvial soil organic matter and carbon fluxes during these events. Results show that biomarkers specific to individual plant species can be used to define the provenance of carbon, quantifying whether more piñon or juniper derived carbon is mobilised from the upland plots, or whether more Larrea tridentata carbon is lost when compared to Bouteloa eripoda losses in the lowlands. The combined approach of monitoring carbon fluxes and tracing types of carbon shows great promise for improved understanding of carbon dynamics in areas subject to rapid vegetation change.

  9. Ultrasonic diagnosis and transurethral incision of ureterocele with hydronephrosis

    DEFF Research Database (Denmark)

    Waaddegaard, P; Miskowiak, J; Stage, P


    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...

  10. Ankle fusion using a 2-incision, 3-screw technique

    NARCIS (Netherlands)

    R.P.M. Hendrickx; G.M.M.J. Kerkhoffs; S.A.S. Stufkens; C.N. van Dijk; R.K. Marti


    Reliable fusion and optimal correction of the alignment of the ankle joint using a 2-incision, 3-screw technique. Symptomatic osteoarthritis of the ankle joint after insufficient other treatment, severe deformity of the osteoarthritic ankle joint, or salvation procedure after failed arthroplasty. Ac

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

    African Journals Online (AJOL)

    primary techniques are unsatisfactory. ... TIP urethroplasty in the management of recurrent ... was used for quantitative data. .... erection and the risk of infection, especially in patients .... currently considered the best tool for complicated .... 10 Mustafa M. The concept of tubularized incised plate hypospadias repair for different ...

  12. Minimal incision surgery in strabismus: Modified fornix-based approach. (United States)

    Pérez-Flores, I


    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.

  13. Mesenchymal stem cells promote incision wound repair in a mouse ...

    African Journals Online (AJOL)

    Full-thickness cutaneous wounds (4 × 2 cm) were made by incision on the dorsal side of the mice. The wound was then ..... on age as well as the type and size of injury. In .... stem cells favour healing of the cutaneous radiation syndrome in a ...

  14. Fontan operation for the Cantrell syndrome using a clamshell incision. (United States)

    Ito, Hiroki; Ota, Noritaka; Murata, Masaya; Sakamoto, Kisaburo


    A median sternotomy could be difficult for a child with ectopia cordis and complex congenital cardiac anomalies. We report a patient with ectopia cordis, functionally single ventricle and bilateral superior vena cava, who underwent a staged Fontan procedure through a clamshell incision and the sternothoracotomy approach.

  15. Surgical removal of large central neurocytomas with small incision approach

    Directory of Open Access Journals (Sweden)

    Shu-mao LU


    Full Text Available Objective To investigate the strategy and technique of small incision surgery through interhemispheric transcallosal approach for removal of large central neurocytomas in supratentorial ventricule. Methods Clinical data and therapy of 6 cases with central neurocytomas were retrospectively studied. All tumors were removed through small incision interhemispheric transcallosal approach, and the clinical data were analyzed. Results Total resection was achieved in all cases. Three cases experienced transient mutism and one case experienced hemiparalysis. All of them received nerve-nurturing treatment and recovered within 2 weeks. Five cases were followed-up from 6 months to 2 years and there was no recurrence. Conclusions The advantages of interhemispheric transcallosal approach include provision of sufficient surgical visual field and space, protection of normal brain tissue by natural cavity and shortest surgical pathway. Small incision surgery may not only reduce invalid brain exposure and hemorrhage during operation, but also decrease operation time. The small incision surgery through interhemispheric transcallosal approach is an effective choice for removal of central neurocytomas involved in supratentorial ventricule.

  16. Time from uterine incision to delivery and hypoxic neonatal outcomes. (United States)

    Spain, Janine E; Tuuli, Methodius; Stout, Molly J; Roehl, Kimberly A; Odibo, Anthony O; Macones, George A; Cahill, Alison G


    The objective of this study was to estimate the association between time from uterine incision to delivery and hypoxic neonatal outcomes in nonanomalous term infants. All women undergoing in-labor term cesarean deliveries (CDs) in the first 2 years of an ongoing prospective cohort study were included. The primary exposure was time in seconds from uterine incision to delivery. The primary outcome was a composite of hypoxia-associated neonatal outcomes, defined as at least one of: seizures, hypoxic ischemic encephalopathy, need for hypothermia treatment, and death within 7 days. Of 812 patients who underwent in-labor CD, the composite hypoxia outcome occurred in 18 (2.2%) neonates. There was no significant difference in the rate of hypoxic morbidity with increasing increments of 60 seconds from uterine incision to delivery (p = 0.35). There was a significantly increased risk of hypoxic morbidity in those delivered in the highest quintile (>240 seconds) compared with those in the lowest quintile (≤ 60 seconds) in cesareans performed for an indication other than nonreassuring fetal status (relative risk, 5.58; 95% confidence interval, 1.30-23.91). Overall, duration from uterine incision to delivery for in-labor cesareans of nonanomalous term infants was not associated with an increase in risk of hypoxia-associated morbidities. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  17. Single-Incision Cholecystectomy in about 200 Patients

    Directory of Open Access Journals (Sweden)

    Roland Raakow


    Full Text Available Background and Aims. We describe our experience of performing transumbilical single-incision laparoendoscopic cholecystectomy as standard procedure for acute and chronic gallbladder diseases. Methods. Between September 2008 and March 2010, 220 patients underwent laparoscopic single-incision surgery. A single port was used for 196 patients and two conventional 5 mm and one 10 mm port in 24 cases. All operations were performed with straight instruments. Results. Single-incision surgery was successfully performed in 215 patients (98%. Three patients (1.4% required conversion to a three-port technique and two patients (0.9% to an open procedure. Average age of 142 women (65% and 78 men (35% was 47 years (range: 15–89, average ASA status 2 (range: 1–3 and BMI 28 (range: 15–49. Mean operative time was 62 minutes (range: 26–174 and 57 patients (26% had histopathological signs of acute cholecystitis. Eleven patients (5% developed to surgery-related complications and nine (4% of these required a reoperation. The mean followup was 331.5 (range: 11–590 days. Conclusion. Transumbilical single-incision cholecystectomy is a feasible and safe new approach for routine cholecystectomy. After a short learning curve, operation time and complication rate are comparable with standard multiport operation. In addition, most cases of acute cholecystitis can be performed with this technique.

  18. Single incision laparoscopic liver resection: a case report

    Institute of Scientific and Technical Information of China (English)

    CAI Xiu-jun; ZHU Zhi-yi; LIANG Xiao; YU Hong; WANG Yi-fan; HE Ji-kai; LI Zhe-yong


    Laparoscopic procedure as a minimally invasive surgery has been introduced into many abdominal surgeries. Smaller incisions of the abdominal wall reduce postoperative pain and the risk of wound complications,and provide an excellent cosmetic result compared with open surgery. Natural orifice transluminal endoscopic surgery (NOTES), a no-scar surgery, is a hot spot of modern surgery.

  19. Laparoskopisk rectumresektion med salpingo-ooforektomi gennem en enkelt incision

    DEFF Research Database (Denmark)

    Bulut, Orhan; Nielsen, Claus B.


    Single-Incision Laparoscopic Surgery (SILS) is an evolving alternative to conventional laparoscopic surgery. We present the case of a low anterior resection combined with left salpingo-oophorectomy performed as a SILS procedure. The patient was a 83-year-old woman, who had a T3N1 rectal cancer 10...

  20. Cosmetic selection of skin incision for resection of choledochal cyst in young female patients (United States)

    Choi, Jong-Woo; Ha, Tae-Yong; Song, Gi-Won; Jung, Dong-Hwan


    Backgrounds/Aims Open surgery for choledochal cyst has a disadvantage of skin incision scar from operative wound, which can be a definite disadvantage especially in young female patients. This study focused on the cosmetic aspect of skin incision for resection of choledochal cyst in young female patients. Methods During a 2-year study period, 11 adult female patients aged less than 40 years underwent primary resection of choledochal cyst by a single surgeon. The cosmetic effect of two types of skin incision was evaluated. Results The patients underwent mini-laparotomy through either a right subcostal incision (n=8) or an upper midline incision (n=3). The mean length of skin incision was 10 cm for right subcostal incisions and 9 cm for upper midline incisions. It took approximately 1 hour to repair the operative wound meticulously in both groups. At the 6 month to 1 year follow-up, a slight bulge on the skin scar was observed in 3 (37.5%) patients of the right subcostal incision group and 1 (33.3%) patient of the upper midline incision group. Conclusions The results of this preliminary study support the claim that cosmetic effect of the upper midline incision for CCD surgery appears to be non-inferior to that of the right subcostal incision if the incision is placed accurately and repaired very meticulously. PMID:27621750

  1. Fluvial geomorphology: where do we go from here? (United States)

    Smith, Derald G.


    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

  2. Avulsion processes at the terminus of low-gradient semi-arid fluvial systems: Lessons from the Río Colorado, Altiplano endorheic basin, Bolivia (United States)

    Donselaar, M. E.; Cuevas Gozalo, M. C.; Moyano, S.


    The Río Colorado dryland river system in the southeast of the endorheic Altiplano Basin (Bolivia) terminates on a very flat coastal plain at the edge of the Salar de Uyuni, the world's largest salt pan with an area of ca. 12,500 km2. Since the Pleistocene the basin has experienced several lake expansion and contraction cycles in response to wetter and drier climate periods, respectively. At present the basin is in a dry climate period which results in a lake level lowstand and progradation of fluvial systems such as the Río Colorado onto the former lake bottom. The present field study of the terminus of the Río Colorado shows that the river experiences a gradual downstream decrease of bankfull width and depth. This bankfull decrease is caused by the combined effects of: (1) extremely low gradient of the lake bottom and, hence, loss of flow energy, and (2) downstream transmission losses due to high evaporation potential and river water percolation through the channel floor. Peak water discharge in seasonal, short-duration rain periods causes massive overbank flooding and floodplain inundation. On satellite images the morphology of the river terminus has a divergent pattern and resembles a network of coeval sinuous distributary channels. However, field observations show that only one channel is active at low flow stage, and at high-flow stage an abandoned, partially infilled channel may be active as well. The active channel at its termination splits into narrow and shallow anastomosing streams before its demise on the lacustrine coastal plain. The rest of the channels which form the divergent network are older sediment-filled abandoned sinuous river courses with multiple random avulsion points. These channel deposits, together with extensive amalgamated crevasse-splay deposits, form an intricate network of fluvial sand deposits. Successive stages of progressively deeper crevasse-channel incision into the floodplain are the result of waning-stage return flow of

  3. Multiple fluvial reworking of impact ejecta—A case study from the Ries crater, southern Germany (United States)

    Buchner, E.; Schmieder, M.


    Impact ejecta eroded and transported by gravity flows, tsunamis, or glaciers have been reported from a number of impact structures on Earth. Impact ejecta reworked by fluvial processes, however, are sparsely mentioned in the literature. This suggests that shocked mineral grains and impact glasses are unstable when eroded and transported in a fluvial system. As a case study, we here present a report of impact ejecta affected by multiple fluvial reworking including rounded quartz grains with planar deformation features and diaplectic quartz and feldspar glass in pebbles of fluvial sandstones from the “Monheimer Höhensande” ~10 km east of the Ries crater in southern Germany.

  4. An Assessment of Hydrology, Fluvial Geomorphology, and Stream Ecology in the Cardwell Branch Watershed, Nebraska, 2003-04 (United States)

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


    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

  5. Multiple time scales of fluvial processes—theory and applications

    Institute of Scientific and Technical Information of China (English)


    Fluvial processes comprise water flow,sediment transport and bed evolution,which normally feature distinct time scales.The time scales of sediment transport and bed deformation relative to the flow essentially measure how fast sediment transport adapts to capacity region in line with local flow scenario and the bed deforms in comparison with the flow,which literally dictates if a capacity based and/or decoupled model is justified.This paper synthesizes the recently developed multiscale theory for sediment-l...

  6. Downstream-migrating fluvial point bars in the rock record (United States)

    Ghinassi, Massimiliano; Ielpi, Alessandro; Aldinucci, Mauro; Fustic, Milovan


    Classical models developed for ancient fluvial point bars are based on the assumption that meander bends invariably increase their radius as meander-bend apices migrate in a direction transverse to the channel-belt axis (i.e., meander bend expansion). However, many modern meandering rivers are also characterized by down-valley migration of the bend apex, a mechanism that takes place without a significant change in meander radius and wavelength. Downstream-migrating fluvial point bars (DMFPB) are the dominant architectural element of these types of meander belts. Yet they are poorly known from ancient fluvial-channel belts, since their disambiguation from expansional point bars often requires fully-3D perspectives. This study aims to review DMFPB deposits spanning in age from Devonian to Holocene, and to discuss their main architectural and sedimentological features from published outcrop, borehole and 3D-seismic datasets. Fluvial successions hosting DMFPB mainly accumulated in low accommodation conditions, where channel belts were affected by different degrees of morphological (e.g., valleys) or tectonic (e.g., axial drainage of shortening basins) confinement. In confined settings, bends migrate downstream along the erosion-resistant valley flanks and little or no floodplain deposits are preserved. Progressive floor aggradation (e.g., valley filling) allow meander belts with DMFPB to decrease their degree of confinement. In less confined settings, meander bends migrate downstream mainly after impinging against older, erosion-resistant channel fill mud. By contrast, tectonic confinement is commonly associated with uplifted alluvial plains that prevented meander-bend expansion, in turn triggering downstream translation. At the scale of individual point bars, translational morphodynamics promote the preservation of downstream-bar deposits, whereas the coarser-grained upstream and central beds are less frequently preserved. However, enhanced preservation of upstream

  7. Lacustrine-fluvial interactions in Australia's Riverine Plains (United States)

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


    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Yang Gyun; Jang, Hyun Seon; Kim, Byung Ock; Kim, Jin Soo [Chosun Univ. College of Dentistry, Gwangju (Korea, Republic of)


    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)


    Directory of Open Access Journals (Sweden)



    Full Text Available INTRODUCTION: Phacoemulsification and foldable IOLs allow modern day surgeon to aim at minimal induction of any astigmatic error as well a s correct any pre-operative refractive errors thus making patients’ life, spectacle free i.e. una ided emmetropia. But its high price and maintenance with a long learning curve for the surg eon make it unsuitable for the Indian camp scenario. Manual SICS in comparison needs a larger incision f or both nucleus removal and a rigid IOL insertion, but still provides for a sutureless and c onvenient alternative to phaco. Manual SICS does induce some amount of astigmatism by altering corneal curvatures (i.e., by coupling effect, while phaco surgery with 3 mm incision is astigmatic ally neutral. Manifold of studies have been done to compare Surgically Induced Astigmatism of ma nual SICS to phaco surgery but not much has been done to compare various techniques in manua l SICS itself. In this study an attempt has been made to analyze t he role of incision site depending on the pre operative keratometry readings in reducing su rgically induced astigmatism in manual small incision cataract surgery.

  10. A laser profilometry technique for monitoring fluvial dike breaching in laboratory experiments (United States)

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


    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. Rheological Consequences of Rapid Erosion in Active Orogens (United States)

    Koons, P. O.; Meltzer, A. S.; Zeitler, P. K.


    It has long been recognized that erosion can influence the geodynamics of an orogen by redistributing mass. However, only recently has it become appreciated that rapid exhumation can locally alter the three-dimensional thermal structure of the crust, profoundly changing its rheology and weakening portions of the crustal profile. This process in turn permits feedbacks between erosion, rheology, and deformation. Specifically, based on geological and geophysical observations at Nanga Parbat in the northwestern Himalaya, we have proposed the "tectonic aneurysm" model, in which significant erosion (at Nanga Parbat, along the large Indus River valley) is sufficient to weaken the crust and divert crustal flow into the region. This in turn facilitates coupled rock uplift and erosion, which further weaken the crust as the shallow thermal gradient steepens, localizing and enhancing deformation. Geological observations at the Nanga Parbat antiform in support of this model include a concentric distribution of metamorphic facies distribution with high-T/low-P granulites at the center, a bulls-eye distribution of very young cooling ages and Neogene decompression melts, and the prevalence of compressional deformation for all young and active structures (which young towards the interior of the antiform). Geophsyical data in the form of dense seismic tomography, distribution of microseismicity, and magnetotelluric measurements document a volume of warm, weak, and resistive crust localized beneath the antiform, none of which appears to be molten to any significant degree. Three-dimensional mechanical models of active incision into a lithosphere with thermally activated lower crust can initialize the aneurysm behavior when fluvial incision occurs along a valley with approximately the same width as the thickness of the frictional upper crust. As the aneurysm grows through positive feedback of advective heating and thermal weakening, the rheological effect becomes dominant over the

  12. Application of a cervical low incision in the functional neck dissection of thyroid papillary carcinoma


    Xu, Jiajie; Chen, Chao; Zheng,ChuanMing; Wang, Kejing; Shang, Jinbiao; FANG, XIANHUA; Ge, Minghua; TAN, ZHUO


    The present study aimed to discuss the advantage of the application of a cervical low incision for functional neck dissection in patients with thyroid papillary carcinoma. The study was a retrospective analysis of 87 thyroid papillary carcinoma patients; cervical low incision in the functional neck dissection was applied for 47 cases and the classic ‘L’ incision was applied for 40 cases. The different integrity, surgical time, blood loss and the aesthetic property of the incision were compare...

  13. 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


    general classification of fluvial landscape development into three temporally distinct deposition phases in the southern Kalahari: (1) A phase of canyon aggradation associated with short lived and spatially restricted flash floods during the early to mid-Holocene; (2) a phase of fan aggradation indicating...... a decrease in flood intensities during the mid- to late Holocene; and (3) a phase of canyon aggradation caused by the occurrence of supra-regional flood events during the Little Ice Age. We interpret the observed spatiotemporal deposition patterns to latitudinal shifts of the tropical easterly circulation...

  14. Fluvial sediment fingerprinting: literature review and annotated bibliography (United States)

    Williamson, Joyce E.; Haj, Adel E.; Stamm, John F.; Valder, Joshua F.; Prautzch, Vicki L.


    The U.S. Geological Survey has evaluated and adopted various field methods for collecting real-time sediment and nutrient data. These methods have proven to be valuable representations of sediment and nutrient concentrations and loads but are not able to accurately identify specific source areas. Recently, more advanced data collection and analysis techniques have been evaluated that show promise in identifying specific source areas. Application of field methods could include studies of sources of fluvial sediment, otherwise referred to as sediment “fingerprinting.” The identification of sediment is important, in part, because knowing the primary sediment source areas in watersheds ensures that best management practices are incorporated in areas that maximize reductions in sediment loadings. This report provides a literature review and annotated bibliography of existing methodologies applied in the field of fluvial sediment fingerprinting. This literature review provides a bibliography of publications where sediment fingerprinting methods have been used; however, this report is not assumed to provide an exhaustive listing. Selected publications were categorized by methodology with some additional summary information. The information contained in the summary may help researchers select methods better suited to their particular study or study area, and identify methods in need of more testing and application.

  15. Fluvial erosion of impact craters: Earth and Mars (United States)

    Baker, V. R.


    Geomorphic studies of impact structures in central Australia are being used to understand the complexities of fluvial dissection in the heavily cratered terrains of Mars. At Henbury, Northern Territory, approximately 12 small meteorite craters have interacted with a semiarid drainage system. The detailed mapping of the geologic and structural features at Henbury allowed this study to concentrate on degradational landforms. The breaching of crater rims by gullies was facilitated by the northward movement of sheetwash along an extensive pediment surface extending from the Bacon Range. South-facing crater rims have been preferentially breached because gullies on those sides were able to tap the largest amounts of runoff. At crater 6 a probable rim-gully system has captured the headward reaches of a pre-impact stream channel. The interactive history of impacts and drainage development is critical to understanding the relationships in the heavily cratered uplands of Mars. Whereas Henbury craters are younger than 4700 yrs. B.P., the Gosses Bluff structure formed about 130 million years ago. The bluff is essentially an etched central peak composed of resistant sandstone units. Fluvial erosion of this structure is also discussed.

  16. Fluvial biogeomorphology in the Anthropocene: Managing rivers and managing landscapes. (United States)

    Viles, Heather


    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.

  17. Late Cretaceous fluvial systems and inferred tectonic history, central Utah

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, T.F.


    Upper Campanian nonmarine sedimentary rocks exposed between the Wasatch Plateau and the Green River in central Utah record a tectonic transition from thin-skinned deformation in the thrust belt to basement-cored uplift in the foreland region. Sandstones within the section consist of two distinct compositional suites, a lower quartzose petrofacies and an upper lithic petrofacies. The volcanic lithic grains of the Farrer and Tuscher Formations were derived from more distal arc sources to the southwest, and transported through the thrust belt somewhere west of the Kaiparowits region, where time-equivalent sedimentary rocks are also rich in volcanic lithic fragments. Disappearance of volcanic lithics and appearance of pebbles at the top of the Tuscher Formation is interpreted to reflect a latest Campanian reorganization of drainage patterns that marked initial growth of the San Rafael swell and similar basement uplifts to the south of the swell. Contemporaneous fluvial systems that deposited the uppermost part of the Price River Formation in the Wasatch Plateau were apparently unaffected by the uplift and continued to flow northeast. Depositional patterns thus indicate that initial growth of the San Rafael swell was probably concurrent with late deformation in the thrust belt. Depositional onlap across the Mesaverde Group by a largely post-tectonic assemblage of fluvial and lacustrine strata (North Horn Formation) indicates a minimum late Paleocene age for growth of the San Rafael swell and deformation within the thrust belt.

  18. Fluvial deposits as an archive of early human activity (United States)

    Mishra, S.; White, M. J.; Beaumont, P.; Antoine, P.; Bridgland, D. R.; Limondin-Lozouet, N.; Santisteban, J. I.; Schreve, D. C.; Shaw, A. D.; Wenban-Smith, F. F.; Westaway, R. W. C.; White, T. S.


    River terraces are well established as an important source of Lower and Middle Palaeolithic artefacts in Europe, large collections having been assembled there during the years of manual gravel extraction. Now that many terrace sequences can be reliably dated and correlated with the oceanic record, potentially useful patterns can be recognized in the distribution of artefacts. The earliest appearance of artefacts in terrace staircases, marking the arrival of the first tool-making hominins in the region in question, is the first of several archaeological markers within fluvial sequences. The Lower to Middle Palaeolithic transition, with the appearance of Levallois, is another. Others may be more regional in significance: the occurrences of Clactonian (Mode 1) industry, twisted ovate handaxes and bout coupé handaxes, for example. IGCP Project no. 449 instigated the compilation of fluvial records from all over the 'old world'. Comparison between British and Central European sequences confirms the established view that there is a demarcation between handaxe making in the west and flake/core industries in the east. Other centres of activity reported here have been in the Middle East (Syria), South Africa and India. Data from such areas will be key in deciphering the story of the earlier 'out-of-Africa' migration, that by pre-Homo sapiens people. There is clear evidence for diachroneity between the first appearances of different industries, in keeping with the well-established idea of northward migration.

  19. Optimality approaches to describe characteristic fluvial patterns on landscapes. (United States)

    Paik, Kyungrock; Kumar, Praveen


    Mother Nature has left amazingly regular geomorphic patterns on the Earth's surface. These patterns are often explained as having arisen as a result of some optimal behaviour of natural processes. However, there is little agreement on what is being optimized. As a result, a number of alternatives have been proposed, often with little a priori justification with the argument that successful predictions will lend a posteriori support to the hypothesized optimality principle. Given that maximum entropy production is an optimality principle attempting to predict the microscopic behaviour from a macroscopic characterization, this paper provides a review of similar approaches with the goal of providing a comparison and contrast between them to enable synthesis. While assumptions of optimal behaviour approach a system from a macroscopic viewpoint, process-based formulations attempt to resolve the mechanistic details whose interactions lead to the system level functions. Using observed optimality trends may help simplify problem formulation at appropriate levels of scale of interest. However, for such an approach to be successful, we suggest that optimality approaches should be formulated at a broader level of environmental systems' viewpoint, i.e. incorporating the dynamic nature of environmental variables and complex feedback mechanisms between fluvial and non-fluvial processes.

  20. Unsteady late Pleistocene incision of streams bounding the Colorado Front Range from measurements of meteoric and in situ 10Be (United States)

    Dühnforth, Miriam; Anderson, Robert S.; Ward, Dylan J.; Blum, Alex


    Dating of gravel-capped strath terraces in basins adjacent to western U.S. Laramide Ranges is one approach to document the history of late Cenozoic fluvial exhumation. We use in situ 10Be measurements to date the broad surfaces adjacent to the eastern edge of the Rocky Mountains in Colorado, and compare these calculated ages with results from meteoric 10Be measurements. We analyze three sites near Boulder, Colorado (Gunbarrel Hill, Table Mountain, and Pioneer) that have been mapped as the oldest terrace surfaces with suggested ages ranging from 640 ka to the Plio-Pleistocene transition. Our in situ 10Be results reveal abandonment ages of 95 ± 129 ka at Table Mountain, 175 ± 27 ka at Pioneer, and ages of 251 ± 10 ka and 307 ± 15 ka at Gunbarrel Hill. All are far younger than previously thought. Inventories of meteoric 10Be support this interpretation, yielding ages that are comparable to Table Mountain and ˜20% lower than Pioneer in situ ages. We argue that lateral beveling by rivers dominated during protracted times of even moderate glacial climate, and that vertical incision rates of several mm/yr likely occurred during times of very low sediment supply during the few interglacials that were characterized by particularly warm climate conditions. In contrast to the traditional age chronology in the area, our ages suggest that the deep exhumation of the western edge the High Plains occurred relatively recently and at an unsteady pace.

  1. Las terrazas fluviales del río Cares: aportaciones sedimentológicas y cronológicas (Picos de Europa, Asturias

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    Ruiz Fernández, Jesús


    Full Text Available The fluvial terraces of the Cares river: sedimentological and chronological contributions (Picos de Europa, Asturias. An analysis of the system of fluvial terraces in the Cares River and its tributaries in Arenas de Cabrales is presented. A total of nine terrace levels were identified with heights of +90 m, +60 m, +60 m, +42-50 m, +20-22 m, +14-17 m, +12 m, +8-10 m, +6-7 m and +5 m above the actual river bed. The sedimentological features of alluvial deposits and their relations with others landforms (stratified debris and alluvial cones have been studied, outlining a chronology for two terrace levels based in absolute datings of 14C, as well as an incision rate of Cares river of 0.24 mm/year during the last 37.000 years.

    Se analiza el sistema de terrazas fluviales del río Cares y sus tributarios, Casaño y Ribeles, en la depresión de Arenas de Cabrales. En concreto, se han identificado un total de nueve niveles de terraza elevados a +90 m, +60 m, +42-50 m, +20-22 m, +14-17 m, +12 m, +8-10 m, +6-7 m y +5 m sobre el nivel actual del río. También se estudian las características sedimentológicas de los depósitos aluviales y su relación con otras formas de modelado, tales como derrubios estratificados y conos torrenciales; y se aporta una cronología para dos niveles de terraza basada en dataciones absolutas de C14, así como una tasa de incisión del río Cares durante los últimos 37.000 años de 0,24 mm/año. [fr] Les terrasses fluviales de la rivière Cares: des contributions sédimentologiques et chronologiques (aux Pics d’Europe, Asturies. On analyse le système des terrasses fluviales de la rivière Cares et de ses affluents, Casaño et Ribeles, à Arenas de Cabrales (Picos de Europa. En somme, on a identifié un total de 9 niveaux de terrasse situés à +90 m, +60 m, +42-50 m, +20-22 m, +14-17 m, +12 m, +8-10 m, +6-7 m et +5 m sur le niveau actuel de la rivière. On étudie aussi les

  2. Applying fluvial geomorphological riffle-pool sequences concept when rebuilding the existing drop hydraulic structure

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    Full Text Available The paper deals with the problem of  rebuilding  the existing water straight drop  structure in Brenna on the Brennica river (Polish Carpathian mountains, which was changed into the rapid hydraulic structure. The technical project was set up in 1988 and finished in the same year. The structure was rebuilt in the field in the early autumn of 1990. One of the concepts of applied fluvial geomorphological solution was used to improve the river channel bed condition. In that case it was found that the existing hydraulic structure reducing river slope and stabilizing river bed can be changed without any harm in to semi-natural riffle structure which could be tolerated by river and organisms living in.  Artificial roughness of the slope plate of the rapid hydraulic structure was obtained by placing cobbles along all the slope apron of the structure. The diameter of cobbles was calculated applying various methods, and the optimum value for that dimension was chosen. The cobbles, used for rebuilding purposes, were taken directly from the riverbed, so that the structure is environmentally similar to the site. All work was done due to European Framework Directive for Rivers.

  3. Castration of dromedary camel through prescrotal midline incision

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    S.A. Taleb


    Full Text Available A total of 165 camels of different ages were castrated through a small, prescrotal midline incision between January, 2010 and December, 2011. The incision was closed with one interrupted, horizontal mattress suture using USP-2 chromic catgut. In 14/165 animals (8.5% postoperative infection (sepsis developed, which healed in two to three weeks after open wound management. The remaining 151 animals had an uneventful recovery, but a slight edematous swelling of the scrotum was observed in 8 of the 151 animals (5.3%, which was self-limiting and of no significance. No primary or secondary postoperative bleeding was noticed in any of the animals. It was concluded that this technique was less time consuming with negligible postoperative care and complications when performed under standard surgical principles.

  4. Closed incision management with negative pressure wound therapy. (United States)

    Dohmen, Pascal M; Misfeld, Martin; Borger, Michael A; Mohr, Friedrich W


    Post-sternotomy mediastinitis is the most severe surgical site infection after sternotomy with an incidence between 1-4% related to the patient co-morbidity. This complication will increase morbidity and mortality and may also have an economic impact. There are guidelines to prevent surgical site infections; however, age and co-morbidities increase and therefore it is important to develop new tools to improve wound healing. This manuscript will give an overview of a new concept using negative pressure wound therapy over a closed incision (so-called, closed incision management) after surgery and will include the principles of negative pressure wound therapy and the positively applied mechanical forces as a permutation of Wolff's law. The use and indication of this therapy is supported by experimental studies divided into physiological and biomechanical property studies. Finally, an overview of clinical studies is given based on the evidence rating scale for therapeutic studies.

  5. Coupling relationships: Hillslope-fluvial linkages in the Hodder catchment, NW England (United States)

    Chiverrell, R. C.; Foster, G. C.; Marshall, P.; Harvey, A. M.; Thomas, G. S. P.


    Variations in the coupling of sediment transfer between different parts of a fluvial catchment, e.g., hillslope to axial stream, can hamper understanding but are an integral part of the geomorphological record. Depositional environments respond to a combination of land use, climate, storms (floods), and autogenic conditioning. The distribution of sediment in the upland landscapes of NW England is out of equilibrium with contemporary climate and geomorphological processes; more a function of peri- and paraglacial mobilisation of glacigenic deposits. Soil and vegetation development after deglaciation have interrupted any progression toward sediment exhaustion with sediment release controlled largely by extrinsic perturbation, with late Holocene anthropogenic activity, climate and extreme hydrological events the likely candidates. This paper presents a new radiocarbon-dated Holocene geomorphological succession for the River Hodder (NW England), alongside evaluating new palaeoecological and geoarchaeological data to discern the impacts of human activity. These data show a late Holocene expansion in human occupation and use of the landscape since the Iron Age (700-0 cal. B.C.), with more substantial changes in the character and intensity of upland land use in the last 1300 years. The geomorphological responses in the uplands were the onset of considerable and widespread hillslope erosion (gullying) and associated alluvial fan development. Interpretation of the regional radiocarbon chronology limits gullying to four, more extensive and aggressive phases after 500 cal. B.C. The downstream alluvial system has responded with considerable valley floor deposition and lateral channel migration that augmented sediment supply by remobilising the existing floodplain terraces and led to the aggradation of a series of inset alluvial terraces. The timing of these changes between states of aggradation and incision in alluvial reaches reflects the increased connectivity between the

  6. Integration of fluvial erosion factors for predicting landslides along meandering rivers (United States)

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


    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 < 3). This may imply that river sediment play different roles between down- and upstream segments. River sediment in the upstream is an erosion agent vertically

  7. Reinterpretation of the Quaternary sedimentary infill of the Ría de Vigo, NW Iberian Peninsula, as a compound incised valley (United States)

    Martínez-Carreño, N.; García-Gil, S.


    Seismic data have been used to investigate the stratigraphy of the Galician rias for more than two decades. Here, we present a new interpretation of the sedimentary infill of an incised valley (Ría de Vigo, NW Iberian Peninsula), based on high-resolution seismic profiles, core sediment analysis, and radiocarbon 14C data. The new data indicate that the stratigraphic architecture of the Galician rias result from multiple incision/infill phases and, therefore, they are reclassified as compound rather than simple incised valleys. Seven seismic units were identified: one of Tertiary age (U1), four of Pleistocene age (U2-U5) which are interpreted as 4th-order sequences deposited between MIS 11 and MIS 2, and Late Pleistocene (U6) and Holocene (U7) units corresponding with post-glacial sedimentation. The sedimentary infill overlies a highly faulted irregular granitic and metamorphic basement; the inherited morphology is shown to be important for controlling the pathway and evolution of the fluvial network as well as preservation of the sedimentary deposits during several glacial/interglacial cycles. The presence of a rocky barrier at the mouth of the ria is a distinctive feature that conditions sedimentation and exchange of sediment between the ria and the adjacent shelf. For the first time, faults and tilted blocks affecting Late Pleistocene (MIS 3) deposits have been identified. The new data presented here provide the opportunity to reconstruct the evolution of the sedimentary infill of a ria, with especially high-resolution during the last post-glacial transgression.

  8. Dominant mechanisms for the delivery of fine sediment and phosphorus to fluvial networks draining grassland dominated headwater catchments. (United States)

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


    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

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

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

    NARCIS (Netherlands)

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


    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

  11. Coastal plain and fluvial deposits in the tertiary of central and northern Spain

    NARCIS (Netherlands)

    Moechtar, H.


    The Ebro Basin represents purely fluvial deposition with a relatively high, but steady tectonic activity in relation to uplift of the Pyrenees and thrust fault activity. The cyclic pattern in the fluvial deposits can be attributed to Milankovitch related climatological changes. In the Loranca Basin

  12. Single incision laparoscopic hepatectomy: Advances in laparoscopic liver surgery

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    Tayar Claude


    Full Text Available Background: Laparoscopic liver surgery is now an established practice in many institutions. It is a safe and feasible approach in experienced hands. Single incision laparoscopic surgery (SILS has been performed for cholecystectomies, nephrectomies, splenectomies and obesity surgery. However, the use of SILS in liver surgery has been rarely reported. We report our initial experience in seven patients on single incision laparoscopic hepatectomy (SILH. Patients and Methods: From October 2010 to September 2012, seven patients underwent single-incision laparoscopic liver surgery. The abdomen was approached through a 25 mm periumbilical incision. No supplemental ports were required. The liver was transected using a combination of LigaSure TM (Covidien-Valleylab. Boulder. USA, Harmonic Scalpel and Ligaclips (Ethicon Endo-Surgery, Inc.. Results: Liver resection was successfully completed for the seven patients. The procedures consisted of two partial resections of segment three, two partial resections of segment five and three partial resections of segment six. The mean operative time was 98.3 min (range: 60-150 min and the mean estimated blood loss was 57 ml (range: 25-150 ml. The postoperative courses were uneventful and the mean hospital stay was 5.1 days (range: 1-13 days. Pathology identified three benign and four malignant liver tumours with clear margins. Conclusion: SILH is a technically feasible and safe approach for wedge resections of the liver without oncological compromise and with favourable cosmetic results. This surgical technique requires relatively advanced laparoscopic skills. Further studies are needed to determine the potential advantages of this technique, apart from the better cosmetic result, compared to the conventional laparoscopic approach.

  13. Open femoral hernia repair: one skin incision for all

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    El-Masry Nabil S


    Full Text Available Abstract Background Femoral hernias are relatively uncommon, however they are the most common incarcerated abdominal hernia, with strangulation of a viscus carrying significant mortality. Classically three approaches are described to open femoral hernia repair: Lockwood's infra-inguinal, Lotheissen's trans-inguinal and McEvedy's high approach. Each approach describes a separate skin incision and dissection to access the femoral sac. The decision as to which approach to adopt, predominantly dependent on the suspicion of finding strangulated bowel, is often a difficult one and in our opinion an unnecessary one. Methods We propose a technique for open femoral hernia repair that involves a single skin incision 1 cm above the medial half of the inguinal ligament that allows all of the above approaches to the hernia sac depending on the operative findings. Thus the repair of simple femoral hernias can be performed from below the inguinal ligament. If found, inguinal hernias can be repaired. More importantly, resection of compromised bowel can be achieved by accessing the peritoneal cavity with division of the linea semilunaris 4 cm above the inguinal ligament. This avoids compromise of the inguinal canal, and with medial retraction of the rectus abdominis muscle enables access to the peritoneal cavity and compromised bowel. Discussion This simple technique minimises the preoperative debate as to which incision will allow the best approach to the femoral hernia sac, allow for alteration to a simple inguinal hernia repair if necessary, and more importantly obviate the need for further skin incisions if compromised bowel is encountered that requires resection.

  14. Field measurements of incision rates following bedrock exposure: Implications for process controls on the long profiles of valleys cut by rivers and debris flows (United States)

    Stock, Jonathan D.; Montgomery, David R.; Collins, Brian D.; Dietrich, William E.; Sklar, Leonard


    Until recently, published rates of incision of bedrock valleys came from indirect dating of incised surfaces. A small but growing literature based on direct measurement reports short-term bedrock lowering at geologically unsustainable rates. We report observations of bedrock lowering from erosion pins monitored over 1–7 yr in 10 valleys that cut indurated volcanic and sedimentary rocks in Washington, Oregon, California, and Taiwan. Most of these channels have historically been stripped of sediment. Their bedrock is exposed to bed-load abrasion, plucking, and seasonal wetting and drying that comminutes hard, intact rock into plates or equant fragments that are removed by higher flows. Consequent incision rates are proportional to the square of rock tensile strength, in agreement with experimental results of others. Measured rates up to centimeters per year far exceed regional long-term erosion-rate estimates, even for apparently minor sediment-transport rates. Cultural artifacts on adjoining strath terraces in Washington and Taiwan indicate at least several decades of lowering at these extreme rates. Lacking sediment cover, lithologies at these sites lower at rates that far exceed long-term rock-uplift rates. This rate disparity makes it unlikely that the long profiles of these rivers are directly adjusted to either bedrock hardness or rock-uplift rate in the manner predicted by the stream power law, despite the observation that their profiles are well fit by power-law plots of drainage area vs. slope. We hypothesize that the threshold of motion of a thin sediment mantle, rather than bedrock hardness or rock-uplift rate, controls channel slope in weak bedrock lithologies with tensile strengths below ∼3–5 MPa. To illustrate this hypothesis and to provide an alternative interpretation for power-law plots of area vs. slope, we combine Shields' threshold transport concept with measured hydraulic relationships and downstream fining rates. In contrast to fluvial

  15. A new, simple operative approach for bilateral inguinal hernia repair in girls: A single transverse supra-pubic incision

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    Abdalla E Zarroug


    Full Text Available Background: Inguinal hernia repair remains one of the most common operations performed by pediatric surgeons. We described a new surgical approach for treating bilateral inguinal hernias in girls through a small single transverse supra-pubic incision. Materials and Methods: A new approach was performed on female children 12-years-old and younger with bilateral inguinal hernias between January 2005 and April 2012. Technique: A single transverse suprapubic incision (1-1.5 cm was made. Using sharp and blunt dissection bilateral hernias were exposed and repaired using a standard high ligation. Results: Ninety-nine girls with a preoperative clinical diagnosis of bilateral inguinal hernia were included. Median age was 2 years (range: 1 month to 12 years. All patients underwent general anesthesia. Median operative time was 12 minutes (range 5-22. There were no intra-operative complications or misdiagnosis. Two patients had bilateral sliding hernias and the remainder had indirect hernias. Post-operatively two patients developed non-expanding small hematomas, both treated non-operatively without sequelae. There were zero hernia recurrence and median follow-up was 5 years (range: 1-8 years on 99% of patients. Conclusion: We described a new, safe, simple, and rapid approach for bilateral inguinal hernia repair in female pediatric population. A single transverse suprapubic skin incision was adequate for exposing both inguinal regions with excellent postoperative results.

  16. Single incision thoracoscopic sympathectomy for palmar and axillary hyperhidrosis

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    Aram Baram


    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.

  17. Modelling of meander migration in an incised channel

    Institute of Scientific and Technical Information of China (English)

    Jianchun HUANG; Blair P GREIMANN; Timothy J RANDLE


    An updated linear computer model for meandering rivers with incision has been developed. The model simulates the bed topography, flow field, and bank erosion rate in an incised meandering channel. In a scenario where the upstream sediment load decreases (e.g., after dam closure or soil conservation), alluvial river experiences cross section deepening and slope flattening. The channel migration rate might be affected in two ways:decreased channel slope and steeped bank height. The proposed numerical model combines the traditional one-dimensional (1D) sediment transport model in simulating the channel erosion and the linear model for channel meandering. A non-equilibrium sediment transport model is used to update the channel bed elevation and gradations. A linear meandering model was used to calculate the channel alignment and bank erosion/accretion, which in turn was used by the 1D sediment transport model. In the 1D sediment transport model, the channel bed elevation and gradations are represented in each channel cross section. In the meandering model, the bed elevation and gradations are stored in two dimensional (2D) cells to represent the channel and terrain properties (elevation and gradation). A new method is proposed to exchange information regarding bed elevations and bed material fractions between 1D river geometry and 2D channel and terrain. The ability of the model is demonstrated using the simulation of the laboratory channel migration of Friedkin in which channel incision occurs at the upstream end.

  18. Minimal incision access for pediatric and adult cochlear implantation

    Institute of Scientific and Technical Information of China (English)

    Cui Danmo; Shi Ying; Su Qiaotong; Liu Ting; Han Demin; Li Yongxin


    Background Cochlear implant surgery is widely practiced.Minimal incision cochlear implant surgery has been developed with the aims of reducing the impact of surgery on the patient and improving cosmesis while maintaining the low morbidity of conventional wider access approaches.This study aimed to assess the surgical technique and complication rate of minimal incision cochlear implantation (MICI) for children and adults.Methods Data for this study were obtained via a retrospective analysis.Totally 378 patients were included in the study.All patients received minimal incision cochlear implantation,using the skin protector during the process of the operation.The surgical complications of MICI were recorded in a spreadsheet format.The incidence of major and minor complication were analyzed,and appropriate treatment was provided.Results A total of 40 (10.5%) complications were noted in the study.There were 0 life-threatening,9 major,and 31 minor complications.Of the nine major complications,five were device failures,one developed infection and extrusion,and three required receiver-stimulator repositioning.Conclusions MICI is as safe as standard cochlear implantation (SCI) and affords with it other benefits.Eliminating the scalp flap avoids devascularization and minimizes the opportunity of flap infection or necrosis.Complications not related to the flap are similar to SCI.

  19. Single incision thoracoscopic sympathectomy for palmar and axillary hyperhidrosis (United States)


    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. PMID:26770711

  20. Bedrock incision by bedload: insights from direct numerical simulations (United States)

    Aubert, Guilhem; Langlois, Vincent J.; Allemand, Pascal


    Bedload sediment transport is one of the main processes that contribute to bedrock incision in a river and is therefore one of the key control parameters in the evolution of mountainous landscapes. In recent years, many studies have addressed this issue through experimental setups, direct measurements in the field, or various analytical models. In this article, we present a new direct numerical approach: using the classical methods of discrete-element simulations applied to granular materials, we explicitly compute the trajectories of a number of pebbles entrained by a turbulent water stream over a rough solid surface. This method allows us to extract quantitatively the amount of energy that successive impacts of pebbles deliver to the bedrock, as a function of both the amount of sediment available and the Shields number. We show that we reproduce qualitatively the behaviour observed experimentally by Sklar and Dietrich (2001) and observe both a "tool effect" and a "cover effect". Converting the energy delivered to the bedrock into an average long-term incision rate of the river leads to predictions consistent with observations in the field. Finally, we reformulate the dependency of this incision rate with Shields number and sediment flux, and predict that the cover term should decay linearly at low sediment supply and exponentially at high sediment supply.

  1. Progressive incision of the Channeled Scablands by outburst floods. (United States)

    Larsen, Isaac J; Lamb, Michael P


    The surfaces of Earth and Mars contain large bedrock canyons that were carved by catastrophic outburst floods. Reconstructing the magnitude of these canyon-forming floods is essential for understanding the ways in which floods modify planetary surfaces, the hydrology of early Mars and abrupt changes in climate. Flood discharges are often estimated by assuming that the floods filled the canyons to their brims with water; however, an alternative hypothesis is that canyon morphology adjusts during incision such that bed shear stresses exceed the threshold for erosion by a small amount. Here we show that accounting for erosion thresholds during canyon incision results in near-constant discharges that are five- to ten-fold smaller than full-to-the-brim estimates for Moses Coulee, a canyon in the Channeled Scablands, which was carved during the Pleistocene by the catastrophic Missoula floods in eastern Washington, USA. The predicted discharges are consistent with flow-depth indicators from gravel bars within the canyon. In contrast, under the assumption that floods filled canyons to their brims, a large and monotonic increase in flood discharge is predicted as the canyon was progressively incised, which is at odds with the discharges expected for floods originating from glacial lake outbursts. These findings suggest that flood-carved landscapes in fractured rock might evolve to a threshold state for bedrock erosion, thus implying much lower flood discharges than previously thought.

  2. Progressive incision of the Channeled Scablands by outburst floods (United States)

    Larsen, Isaac J.; Lamb, Michael P.


    The surfaces of Earth and Mars contain large bedrock canyons that were carved by catastrophic outburst floods. Reconstructing the magnitude of these canyon-forming floods is essential for understanding the ways in which floods modify planetary surfaces, the hydrology of early Mars and abrupt changes in climate. Flood discharges are often estimated by assuming that the floods filled the canyons to their brims with water; however, an alternative hypothesis is that canyon morphology adjusts during incision such that bed shear stresses exceed the threshold for erosion by a small amount. Here we show that accounting for erosion thresholds during canyon incision results in near-constant discharges that are five- to ten-fold smaller than full-to-the-brim estimates for Moses Coulee, a canyon in the Channeled Scablands, which was carved during the Pleistocene by the catastrophic Missoula floods in eastern Washington, USA. The predicted discharges are consistent with flow-depth indicators from gravel bars within the canyon. In contrast, under the assumption that floods filled canyons to their brims, a large and monotonic increase in flood discharge is predicted as the canyon was progressively incised, which is at odds with the discharges expected for floods originating from glacial lake outbursts. These findings suggest that flood-carved landscapes in fractured rock might evolve to a threshold state for bedrock erosion, thus implying much lower flood discharges than previously thought.


    Directory of Open Access Journals (Sweden)

    Jonas Otaviano Praça de Souza


    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.

  4. Complications from a Distal Bicep Repair: A Meta-Analysis of a Single Incision Versus Double Incision Surgical Technique


    Toossi, Nader; Amin, Nirav Hasmukh; Cerynik, Douglas L.; Jones, Morgan H.


    Objectives: Anatomical reinsertion of the distal biceps is critical for restoring elbow flexion and forearm supination strength. Surgical techniques utilizing one and two incisions have been reported in the literature, describing complications and outcomes. However, which technique is associated with a lower complication rate remains unclear. Methods: A systematic review was conducted using the PubMed, Medline, CINAHL (Cumulative Index to Nursing and Allied Health Literature), SPORTSDiscus, a...

  5. Dating fluvial archives of the Riverine Plain, Southeastern Australia (United States)

    Mueller, Daniela; Cohen, Tim; Reinfelds, Ivars; Jacobs, Zenobia; Shulmeister, James


    The Riverine Plain of Southeastern Australia is characterized by a multiplicity of relict river channels. Compared to the modern drainage system the most prominent of those distinct features are defined by large bankfull channel widths, large meander wavelengths and coarse sediment loads. Such morphological differences provide evidence for regimes of higher discharge, stemming from significant changes in runoff volumes, flood-frequency regimes and sediment supply. An existing geochronology for some of these channels is based on multi-grain thermoluminescence (Murrumbidgee River; Page et al., 1996) or radio-carbon dating (Goulburn River; Bowler, 1978) and indicates enhanced fluvial activity between 30 to 13 ka. The absence of exact Last Glacial Maximum (LGM, 21 ± 3 ka) ages of the Murrumbidgee palaeochannels was interpreted to indicate decreased fluvial activity during the peak of the LGM but was not inferred for the nearby Goulburn River. Recent developments in optical dating, especially measurements of individual grains of quartz, allow for an examination of these previous findings. Key sites along the Murrumbidgee and Goulburn Rivers have been revisited and new sites of the adjacent Murray River have been investigated. A revised, high-resolution geochronology based on single-grain optically stimulated luminescence dating is used to examine the precise occurrence of those massive channels and their implications for the Southern Hemisphere LGM. References: Page, K., Nanson, G., Price, D. (1996). Chronology of Murrumbidgee River palaeochannels on the Riverine Plain, southeastern Australia. Journal of Quaternary Science 11(4): 311-326. Bowler, J. (1978). Quaternary Climate and Tectonics in the Evolution of the Riverine Plain, Southeastern Australia. In: Davies, J. & Williams, M. (Editors). Landform Evolution in Australia, Australian National University Press: Canberra. p. 70-112.

  6. Progress in faunal correlation of Late Cenozoic fluvial sequences 2000 4: the report of the IGCP 449 biostratigraphy subgroup (United States)

    Schreve, D. C.; Keen, D. H.; Limondin-Lozouet, N.; Auguste, P.; Santisteban, Juan I.; Ubilla, M.; Matoshko, A.; Bridgland, D. R.; Westaway, R.


    Vertebrate and invertebrate faunal biostratigraphy is a well-tested method for establishing relative chronologies for fluviatile sequences that has proved useful in many parts of the world. The robust bones and teeth of large mammals are commonly found in fluviatile deposits, whereas small vertebrates can be readily recovered through systematic sieving of calcareous sediments, as can molluscs, the other major faunal group that has been used for biostratigraphical analysis of fluvial sequences. Because of their rapid and quantifiable rates of evolution, extinction, body mass change and dispersal during the Late Cenozoic, mammals are especially useful for ordering the fragmentary terrestrial sequence of interglacials and glacials, and proposing correlation with the global marine climatostratigraphic record. Other groups (e.g. reptiles and amphibians, ostracods) are as yet only in the initial stages of development as a dating tool, whereas some (e.g. fish, birds) still require substantial development in order to fully explore their utility. As part of IGCP 449, vertebrate and molluscan assemblages have made important contributions to datasets from a number of areas, notably northern France, central Germany, the Czech Republic and the Ukraine. Further south, mammalian assemblages have proved useful in separating discrete periods of climatic change in Iberia and Syria. At greater distances from the core area of fluvial biostratigraphical archives, significant contributions have come from South America (Uruguay River), South Africa (Vaal) and Australia (Riverine Plain and Lake Eyre drainage basin).

  7. Quaternary fluvial response to climate change in glacially influenced river systems (United States)

    Cordier, Stéphane; Adamson, Kathryn; Delmas, Magali; Calvet, Marc; Harmand, Dominique


    Over the last few decades, many studies in Europe and other continents have focused on the fluvial response to climate forcing in unglaciated basins. However, glacial activity may have a profound impact on the behaviour of the fluvial systems located downstream. In comparison to ice-free basins, these systems are characterised by distinctive hydrological and sediment supply regimes. Over Quaternary timescales, the fluvial records are influenced by periglacial (in non-glaciated areas), proglacial, and paraglacial processes. Understanding the impacts of these processes on the formation and preservation of the Quaternary geomorphological and sedimentary archives is key for our understanding of glacial-fluvial interactions. We investigate the impact of Quaternary glacial activity on fluvial sediment transfer, deposition, and preservation. Using existing studies from across Europe, we create a database of glaciofluvial geomorphology, sedimentology, and geochronology. This is used to examine how glacial forcing of fluvial systems varies spatially in different basin settings, and temporally over successive Milankovitch cycles. In particular, we focus on the ways in which the primary glacial-fluvial depositional signal could be distinguished from periglacial and paraglacial reworking and redeposition.

  8. In vivo and in vitro analysis of topographic changes secondary to DSAEK venting incisions

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    Church D


    Full Text Available Majid Moshirfar, Monette T Lependu, Dane Church, Marcus C Neuffer John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA Introduction: Descemet’s stripping automated endothelial keratoplasty (DSAEK venting incisions may induce irregular corneal astigmatism. The study examines in vivo and in vitro astigmatic effects of venting incisions. Patients and methods: In vivo analysis examined eleven eyes of eleven patients who had received DSAEK with venting incisions. A chart review of the eleven eyes including assessment of pre and postoperative refraction and topography was performed. In vitro analysis examined three cadaver eyes which received topographic imaging followed by venting incisions at 4 mm, 6 mm, and 7 mm optical zones. Topographic imaging was then performed again after the incisions. Results: Postoperative topographies of eleven eyes demonstrated localized flattening at incision sites and cloverleaf pattern astigmatism. There was a significant difference in corneal irregularity measurement (P = 0.03, but no significant difference in shape factor or change of topographic cylinder. The cloverleaf pattern was found in cadaver eyes with incisions placed at 4 mm and 6 mm optical zones but not at the 7 mm zone. Conclusion: DSAEK venting incisions can cause irregular corneal astigmatism that may affect visual outcomes. The authors recommend placement of venting incisions near the 7 mm optical zone. Keywords: DSAEK, venting incisions, endothelial keratoplasty, astigmatism, endothelium, endothelial transplant

  9. The clinical significance of abdominal right lower paramedian incision inrectal cancer operation

    Institute of Scientific and Technical Information of China (English)

    Chong Shu Wang; Shou Jiang Wei; Jing Dong Li


    AIM The incision in rectal cancer operation is adopted commonly in the left mid-lower abdomen. But thereare some defects for the incision, which is close to the artificial colotomy, readily be contaminated by feces,difficult to treat the lesions in hepatic and cholecystic area at the same time and in the weakened area ofabdominal wall. So, we employed the abdominal right lower paramedian incision to solve these problems.METHODS The abdominal right lower paramedian incision is from publc tubercle upward to 3 cm- 4 cmabove navel. The incision should be extended upward if individual need of performing hepatic and cholecysticoperation, or placing catheter or pump in hepatic artery or portal vein for chemotherapy at the same time.RESULTS One hundred and eighty three cases with rectal cancer were adopted this incision in differentoperation procedure, and out of them 41 patients were taken different operation on hepatic and cholecysticlesions and place a catheter or pump to hepatic artery or portal vein. Operators feel that the incision dose nothinder exploring and operating in all of the patients.CONCLUSION The right lower paramedian incision of abdomen is far away from the artificial colotomy,and it can reduce the feces contamination, lower down the rate of incision hernia and paramedian hernia orfistula. Furthermore, it is easy to treat the complicated hepatic and cholecystic lesion. So, authors suggestthat this incision is useful for the operation of rectal cancer, and it is worth to populize in clinical practice.

  10. Standardized technique for single-incision laparoscopicassisted stoma creation

    Institute of Scientific and Technical Information of China (English)

    Norikatsu Miyoshi; Shiki Fujino; Masayuki Ohue; Masayoshi Yasui; Shingo Noura; Yuma Wada; Ryuichiro Kimura; Keijiro Sugimura; Akira Tomokuni; Hirofumi Akita; Shogo Kobayashi; Hidenori Takahashi; Takeshi Omori; Yoshiyuki Fujiwara; Masahiko Yano


    To describe the procedure, efficacy, and utility of singleincision laparoscopic-assisted stoma creation(SILStoma) for transverse colostomy. Using single-incision laparoscopic surgery, we developed a standardized technique for SILStoma. Twelve consecutive patients underwent SILStoma for transverse colostomy at Osaka Medical Center for Cancer and Cardiovascular Diseases from April 2013 to March 2016. A single, intended stoma site was created with a 2.5-3.5 cm skin incision for primary access to the intra-abdominal space, and it functioned as the main port through which multi-trocars were placed. Clinical and operative factors and postoperative outcomes were evaluated. Patient demographics, including age, gender, body mass index, and surgical indications for intestinal diversion were evaluated. SILStoma was performed in nine cases without the requirement of additional ports. In the remaining three cases, 1-2 additional 5-mm ports were required for mobilization of the transverse colon and safe dissection of abdominal adhesions. No cases required conversion to open surgery. In all cases, SILStoma was completed at the initial stoma site marked preoperatively. No intraoperative or postoperative complications greater than Grade Ⅱ(the Clavien-Dindo classification) were reported in the complication survey. Surgical site infection at stoma sites was observed in four cases; however, surgical interventions were not required and all infectionswere cured completely. In all cases, the resumption of bowel movements was observed between postoperative days 1 and 2. SILStoma for transverse loop colostomy represents a feasible surgical procedure that allows the creation of a stoma at the preoperatively marked site without any additional large skin incisions.

  11. Conjunctival inclusion cysts following small incision cataract surgery

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    Narayanappa Shylaja


    Full Text Available The occurrence of acquired conjunctival inclusion cysts following various ophthalmic surgeries such as strabismus surgery, scleral buckling, pars plana vitrectomy, ptosis surgery and phacoemulsification has been reported. We report two cases of conjunctival inclusion cysts following manual Small Incision Cataract Surgery (SICS in two male patients aged 65 and 67 years. The cysts originated from the scleral tunnel used for manual SICS. Both were treated by excision and confirmed histopathologically. No recurrence was noted at three months follow-up. To our knowledge, conjunctival inclusion cysts following SICS have not been reported previously. Careful reflection of conjunctiva during tunnel construction and posterior chamber intraocular lens implantation may prevent their occurrence.

  12. Landform Evolution Modeling of Specific Fluvially Eroded Physiographic Units on Titan (United States)

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


    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.

  13. Ground water stratification and delivery of nitrate to an incised stream under varying flow conditions. (United States)

    Böhlke, J K; O'Connell, Michael E; Prestegaard, Karen L


    Ground water processes affecting seasonal variations of surface water nitrate concentrations were investigated in an incised first-order stream in an agricultural watershed with a riparian forest in the coastal plain of Maryland. Aquifer characteristics including sediment stratigraphy, geochemistry, and hydraulic properties were examined in combination with chemical and isotopic analyses of ground water, macropore discharge, and stream water. The ground water flow system exhibits vertical stratification of hydraulic properties and redox conditions, with sub-horizontal boundaries that extend beneath the field and adjacent riparian forest. Below the minimum water table position, ground water age gradients indicate low recharge rates (2-5 cm yr(-1)) and long residence times (years to decades), whereas the transient ground water wedge between the maximum and minimum water table positions has a relatively short residence time (months to years), partly because of an upward increase in hydraulic conductivity. Oxygen reduction and denitrification in recharging ground waters are coupled with pyrite oxidation near the minimum water table elevation in a mottled weathering zone in Tertiary marine glauconitic sediments. The incised stream had high nitrate concentrations during high flow conditions when much of the ground water was transmitted rapidly across the riparian zone in a shallow oxic aquifer wedge with abundant outflow macropores, and low nitrate concentrations during low flow conditions when the oxic wedge was smaller and stream discharge was dominated by upwelling from the deeper denitrified parts of the aquifer. Results from this and similar studies illustrate the importance of near-stream geomorphology and subsurface geology as controls of riparian zone function and delivery of nitrate to streams in agricultural watersheds.

  14. Combining information preserved in fluvial topography and strath terraces to extract rock uplift rates in the Apennines (United States)

    Fox, M.; Brandon, M. T.


    Longitudinal river profiles respond to changes in tectonic uplift rates through climate-modulated erosion. Therefore, rock uplift rate information should be recorded in fluvial topography and extracting this information provides crucial constraints on tectonic processes. In addition to the shape of the modern river profile, paleo-river profiles can often be mapped in the field by connecting strath terraces. These strath terraces act as markers that record complex incision histories in response to rock uplift rates that vary in space and time. We exploit an analytical linear solution to the linear version (n=1) of the stream-power equation to efficiently extract uplift histories from river networks and strath terraces. The analytical solution is based on the transient solution to the linear version (n=1) of the stream-power equation. The general solution to this problem states that the elevation of a point in a river channel is equal to the time integral of its uplift history, where integration is carried out over the time required for an uplift signal to propagate from the baselevel of the river network to the point of interest. A similar expression can be written for each strath terrace in the dataset. Through discretization of these expressions into discrete timesteps and spatial nodes, a linear system of equations can be solved using linear inverse methods. In this way, strath terraces and river profiles can be interpreted in an internally consistent framework, without the requirement that the river profile is in a steady state. We apply our approach to the Northern Apennines where strath terraces have been extensively mapped and dated. Comparison of our inferred rock uplift rate history with modern rock uplift rates enables us to distinguish short-term deformation on a buried thrust fault with long-term mountain building processes.

  15. Anterior ilioinguinal incision for drainage of high-located perianal abscess. (United States)

    Peng, K-T; Hsieh, M-C; Hsu, W-H; Li, Y-Y; Yeh, C-H


    Most perianal abscesses originate from infected anal glands at the base of the anal crypts. Most abscesses below are usually drained through perianal incision and can be treated successfully. However, when perianal abscesses extend to the high intrapelvic cavity, it may be inadequate treatment through a single route incision through a perianal approach. The aim of this technical note is to show that combined anterior ilioinguinal and perianal incisions may provide optimal surgical field and multiple drainages. Here, we report a 56-year-old male patient with perianal-originating parapsoas abscesses. Residual abscess still remained after initial perianal incision and drainage after 1-month treatment. We presented combined anterior ilioinguinal and perianal incision technique methods for proper drainage in this complicated case. No recurrent or residual abscess remained after 2 weeks of operation. So, combined anterior ilioinguinal incision is feasible for high-located perianal abscess.

  16. Optical stimulated Luminescence Signal on Modern Fluvial Deposit in Taiwan (United States)

    Chen, Y. G.; Wu, T. S.; Chen, Y. W.; Kuo, Y. T.


    The river terraces overlain by fluvial and debris-flow deposit are widely distributed in Taiwan due to its active tectonic situation. They are not only critical in reconstructing the river evolution, but also of importance in understanding neotectonics. However, the age estimation for the terraces has their own problems by C-14 as well as OSL (Optical Stimulated Luminescence) dating method. For C-14 method, the major problem is the difficulty in discovering the suitable samples, but for OSL method the zeroing effect of the sediments becomes the major barrier if quartz SAR (Single Aliquot Regenerative) procedure is applied. In order to test the residual dose from different drainage areas in Taiwan, modern deposits were collected from 13 main rivers and 3 samples for each from upper-stream to downstream. The apparent dose of modern fluvial deposit was defined as residual dose and believed to be able to give a hint for estimating the zeroing effect for river terraces. Quartz SAR OSL procedure on small aliquot was adopted for all samples in this study. Our results show the residual dose in western Taiwan strongly relies on the source from. If we further apply the mean value of smallest 5% on samples from modern debris flow deposits in upper-stream, the residual dose rise up as high as ~40Gy but lower down to ~15Gy for samples collected from river mouth estuary. It implies that there will be a large error when evaluating the age of debris deposit terrace by quartz SAR OSL procedure. However, if the modern river does not suffer from debris flow in upper-stream, the residual dose is ~5Gy in upper stream and only -0.7~2Gy to the lower steam estuary, which provide better chance to derive relatively reliable ages. We also find that the luminescence characteristics is different between the samples in western and eastern Taiwan respectively. The quartz grains from eastern Taiwan are much dimer than those of the western Taiwan. We may therefore face severe challenge to approach

  17. 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)


    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.

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

    Directory of Open Access Journals (Sweden)

    Benzing, Christian


    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.

  19. Endoscopy-assisted cerebral falx incision via unilateral

    Directory of Open Access Journals (Sweden)

    DONG Ji-rong


    Full Text Available 【Abstract】Objective: To investigate the clinical features and treatment strategy of dissymmetric bilateral frontal contusion, and to summarize our experience in treat-ing these patients by minimally invasive surgery. Methods: Over the past 3 years, we have treated a total of 31 patients with dissymmetric bilateral frontal contusion using endoscopy-assisted unilateral cerebral falx incision. Other 30 patients treated by routine bilateral approaches within the same period were taken as control. Results: Seventeen cases (54.8% in the unilateral operation group survived and were in good condition, 8 (25.8% had moderate disability, 4 (12.9% had severe disability, 1 (3.2% was in vegetative state, and 1 (3.2% died. Compared with the control group, the Glasgow Out-come Scale score was not significantly different in the uni-lateral operation group, but the operation time, blood trans-fusion volume, the length of hospital stay, the incidences of mental disorder and olfactory nerve injury were greatly reduced in the unilateral operation group. Conclusions: Endoscopy-assisted unilateral cerebral falx incision can shorten the operation time, reduce surgical trauma and complications in treatment of patients with dis-symmetric bilateral frontal contusion. It can obviously di-minish the chance of delayed intracerebral hematoma and subsequently minimize the incidences of subfalcial and centrencephalic herniation. Key words: Brain injuries; Intracranial hemorrage, traumatic; Endoscopy; Surgically procedures, minimally invasive

  20. Avoiding Facial Incisions with Midface Free Tissue Transfer (United States)

    Stalder, Mark W.; Sosin, Michael; Urbinelli, Leo J.; Mayo, James L.; Dorafshar, Amir H.; Hilaire, Hugo St.; Borsuk, Daniel E.


    Background: We have adopted an intraoral microsurgical anastomosis to the facial vessels to eliminate the need for any visible facial incisions. Methods: Cadaveric dissection was used to demonstrate accessibility of the facial artery and vein through an intraoral approach. Additionally, 5 patients underwent free tissue transfer for reconstruction of major defects of the midface through an intraoral, transmucosal approach, obviating the need for visible skin incisions. Results: The pathology included palatal defects due to mucoepidermoid carcinoma and ischemic necrosis from cocaine abuse, maxillary defects secondary to fibrous dysplasia and avascular necrosis from traumatic blast injury, and a residual posttraumatic bony deformity of the zygoma. Reconstructions were performed with a free ulnar forearm flap, a free vastus lateralis muscle flap, a deep circumflex iliac artery myoosseous flap, a free fibula flap, and a deep circumflex iliac artery osseous flap, respectively. The facial artery and vein were used as recipient vessels for microvascular anastomosis for all cases. Mean follow-up was 12.2 months. All free tissue transfers were successful, and each patient had a satisfactory aesthetic outcome with no associated facial scars. Conclusion: This technique can be employed during reconstruction of an array of bony or soft-tissue midface deficits with minimal morbidity. This small series effectively demonstrates the varied pathologies and tissue deficiencies that can be successfully reconstructed with free tissue transfer using an entirely intraoral approach to the recipient facial vessels, resulting in no visible scars on the face and an improvement in the overall aesthetic outcome. PMID:28280662

  1. [Our experience with prostatic incision (TUIP) with local anesthesia]. (United States)

    Del Boca, C; Colloi, D; Guardamagna, A; Bolis, C; Giuberti, A C; Tzoumas, S; Ferrari, C


    The Authors present their experience in the treatment of prostatic obstruction with bladder neck incision (TUIP) performed under local anesthesia. An Hulbert 6 Fr endoscopic needle is used to infiltrate the prostatic area submitted to TUIP with 200 mg of Lidocaine 2%. The TUIP was done with a single deep incision at 7 hours using a 24 Fr Iglesias resector with Collins device. 28 patients with an age range from 69 to 85 years (mean 74) affected by IPB in an obstructed fase were submitted to this procedure. Various parameters were achieved for the selection of the patients: urodynamic diagnosis of low urinary tract obstruction, prostatic volume less than 50 ml without important prostatic median lobe, high anesthesiological risk, absence of correlated vesical complications. A clinical follow up was done at 1-6 and 12 months. The results obtained showed a good compliance of the patients treated with satisfactory urodynamic patterns. The Authors conclude that this less invasive approach, in selected cases, is the treatment of choice not only for low invasivity and morbidity rate but also for the reduced time of catheterization, hospitalization and costs.

  2. Pain-related mediators underlie incision-induced mechanical nociception in the dorsal root ganglia

    Institute of Scientific and Technical Information of China (English)

    Xiuhong Yuan; Xiangyan Liu; Qiuping Tang; Yunlong Deng


    Approximately 50-70% of patients experience incision-induced mechanical nociception after sur-gery. However, the mechanism underlying incision-induced mechanical nociception is stil unclear. Interleukin-10 and brain-derived neurotrophic factor are important pain mediators, but whether in-terleukin-10 and brain-derived neurotrophic factor are involved in incision-induced mechanical no-ciception remains uncertain. In this study, forty rats were divided randomly into the incision surgery (n=32) and sham surgery (n=8) groups. Plantar incision on the central part of left hind paw was performed under anesthesia in rats from the surgery group. Rats in the sham surgery group re-ceived anesthesia, but not an incision. Von Frey test results showed that, compared with the sham surgery group, incision surgery decreased the withdrawal threshold of rats at 0.5, 3, 6 and 24 hours after incision. Immunofluorescence staining in the dorsal root ganglia of the spinal cord (L 3-5 ) showed that interleukin-10 and brain-derived neurotrophic factor were expressed mainly on smal-and medium-sized neurons (diameter40μm) at 6 and 24 hours after incision surgery, which corresponded to the decreased mechanical withdrawal threshold of rats in the surgery group. These experimental findings suggest that expression pattern shift of interleukin-10 and brain-derived neurotrophic factor induced by inci-sion surgery in dorsal root ganglia of rats was closely involved in lowering the threshold to me-chanical stimulus in the hind paw fol owing incision surgery. Pain-related mediators induced by in-cision surgery in dorsal root ganglia of rats possibly underlie mechanical nociception in ipsilateral hind paws.

  3. Correlation between Corneal Endothelial Cell Loss and Location of Phacoemulsification Incision

    Directory of Open Access Journals (Sweden)

    Hamid Gharaee


    Full Text Available Purpose: To assess the relationship between corneal endothelial cell loss after phacoemulsification and the location of the clear corneal incision. Methods: A total of 92 patients (92 eyes with senile cataracts who met the study criteria were included in this cross sectional study and underwent phacoemulsification. The incision site was determined based on the steep corneal meridian according to preoperative keratometry. Endothelial cell density was measured using specular microscopy in the center and 3 mm from the center of the cornea in the meridian of the incisions (temporal, superior, and superotemporal. Phacoemulsification was performed by a single surgeon using the phaco chop technique through a 3.2 mm clear cornea incision. Endothelial cell loss (ECL was evaluated 1 week, and 1 and 3 months postoperatively. Results: At all time points during follow-up, ECL was comparable among the 3 incision sites, both in the central cornea and in the meridian of the incision (P > 0.05 for all comparisons. However, 3 months postoperatively, mean central ECL with superior incisions and mean sectoral ECL with temporal incisions were slightly higher. Superotemporal incisions entailed slightly less ECL than the other 2 groups. Overall, one month after surgery, mean central ECL was 10.8% and mean ECL in the sector of the incisions was 14.0%. Axial length and effective phaco time (EFT were independent predictors of postoperative central ECL (P values 0.005 and < 0.0001, respectively. Conclusion: A superotemporal phacoemulsification incision may entail less ECL as compared to other incisions (although not significantly different. The amount of central ECL may be less marked in patients with longer axial lengths and with procedures utilizing less EFT.

  4. Downstream mixing of sediment and tracers in agricultural catchments: Evidence of changing sediment sources and fluvial processes? (United States)

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


    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

  5. Fluvial processes and vegetation - Glimpses of the past, the present, and perhaps the future. (United States)

    Hupp, Cliff R.; Osterkamp, Waite R.


    "Most research before 1960 into interactions among fluvial processes, resulting landforms, and vegetation was descriptive. Since then, however, research has become more detailed and quantitative permitting numerical modeling and applications including agricultural-erosion abatement and rehabilitation of altered

  6. Metabolism of mineral-sorbed organic matter and microbial lifestyles in fluvial ecosystems

    NARCIS (Netherlands)

    Hunter, W.R.; Niederdorfer, R.; Gernand, A.; Veuger, B.; Prommer, J.; Mooshammer, M.; Wanek, W.; Battin, T.J.


    In fluvial ecosystems mineral erosion, carbon (C), and nitrogen (N) fluxes are linked via organomineral complexation, where dissolved organic molecules bind to mineral surfaces. Biofilms and suspended aggregates represent major aquatic microbial lifestyles whose relative importance changes predictab

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

    Directory of Open Access Journals (Sweden)

    Pengyu Gao


    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.

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

  9. In vivo and in vitro analysis of topographic changes secondary to DSAEK venting incisions. (United States)

    Moshirfar, Majid; Lependu, Monette T; Church, Dane; Neuffer, Marcus C


    Descemet's stripping automated endothelial keratoplasty (DSAEK) venting incisions may induce irregular corneal astigmatism. The study examines in vivo and in vitro astigmatic effects of venting incisions. In vivo analysis examined eleven eyes of eleven patients who had received DSAEK with venting incisions. A chart review of the eleven eyes including assessment of pre and postoperative refraction and topography was performed. In vitro analysis examined three cadaver eyes which received topographic imaging followed by venting incisions at 4 mm, 6 mm, and 7 mm optical zones. Topographic imaging was then performed again after the incisions. Postoperative topographies of eleven eyes demonstrated localized flattening at incision sites and cloverleaf pattern astigmatism. There was a significant difference in corneal irregularity measurement (P = 0.03), but no significant difference in shape factor or change of topographic cylinder. The cloverleaf pattern was found in cadaver eyes with incisions placed at 4 mm and 6 mm optical zones but not at the 7 mm zone. DSAEK venting incisions can cause irregular corneal astigmatism that may affect visual outcomes. The authors recommend placement of venting incisions near the 7 mm optical zone.

  10. Thoracoscopic reoperation for recurrent pneumothorax after single-incision thoracoscopic surgery. (United States)

    Sano, Atsushi; Kawashima, Mitsuaki


    An 18-year-old male patient who had undergone single-incision thoracoscopic surgery for left spontaneous pneumothorax was diagnosed with bilateral recurrent pneumothorax. We performed thoracoscopic reoperation and observed adhesions between the previous incision and the left lung. A bulla that was thought to be the cause of the recurrent left pneumothorax was found on the mediastinal side of previously ligated lesions. Longer incisions during single-incision thoracoscopic surgery may be more likely to cause adhesions. Despite the restricted view during surgery, care must be taken to identify all bullae. Use of reinforcement techniques is also important to prevent recurrence.

  11. First Report: Linear Incision for Placement of a Magnetically Coupled Bone-Anchored Hearing Implant. (United States)

    Barry, Jonnae Y; Reghunathan, Saranya; Jacob, Abraham


    Discuss use of a linear incision for placement of a magnetically coupled bone anchored hearing implant. Case series. Two patients underwent placement of magnetically coupled bone-anchored hearing implants (BAHI) through linear incisions. The first, a 40-year-old female with congenital single-sided deafness, previously had successful implantation of a percutaneous bone anchored hearing implant through a linear incision; unfortunately, she developed pain and intermittent drainage at her abutment site with time, resulting in a request for removal of her device. As an alternative to complete removal, we offered to replace the percutaneous implant with a magnetically coupled BAHI, employing the same linear incision previously. The second patient, a 53-year-old obese female with limited neck mobility and mixed hearing loss, underwent primary placement of a magnetically coupled BAHI through a linear incision. Limitations in neck mobility and patient body habitus precluded use of a traditional C-shaped incision. Both patients underwent surgery successfully, healed without incident, had their devices activated 6 weeks after their procedures, and are able to wear their implants more than 8 hours per day without discomfort. Surgical techniques for bone-anchored implants continue to evolve. Though manufacturers of magnetically coupled devices recommend using C-shaped incisions with large skin flaps, our first reported cases suggest that a small linear incision immediately overlying the implant magnet may be an acceptable alternative. Potential benefits include a smaller incision, less hair removal, smaller flap, decreased surgical time, and less postoperative pain.

  12. Histomorphological and immunofluorescence evaluation of bimanual and coaxial phacoemulsification incisions in rabbits. (United States)

    Johar, S R Kaid; Vasavada, Abhay R; Praveen, Mamidipudi R; Pandita, Deepak; Nihalani, Bharati; Patel, Udayan; Vemuganti, Geeta


    To compare the changes in the histomorphology and immunofluorescence of collagen type I in clear corneal incisions (CCIs) at the end of bimanual and coaxial phacoemulsification in rabbits. Iladevi Cataract and IOL Research Centre, Ahmedabad, India. In this randomized study, the left eye of 30 rabbits had bimanual phacoemulsification through 1.2 mm CCIs for phaco tip access accompanied by an additional 1.4 mm incision for irrigating chopper access or coaxial phacoemulsification through a 2.6 mm single-plane CCI. The right eyes acted as controls. Samples collected at the end of surgery were processed for histomorphology using periodic acid-Schiff-hematoxylin staining and immunofluorescence localization of type I collagen. Incisions exposed to bimanual phacoemulsification had loss of epithelium, stromal fiber shrinkage, keratocyte nuclei fragmentation and condensation, ragged tunnel margins, and Descemet membrane and endothelial cell loss. The changes were minimal or absent in incisions exposed to coaxial phacoemulsification. Immunofluorescence showed a loss of parallel arrangement of type I collagen fibers in bimanual phacoemulsification incisions, while the fibers were well preserved in coaxial phacoemulsification incisions. The changes were more prominent in the roof of the incision tunnel than in the floor. Corneal incisions for bimanual phacoemulsification were more prone to damage than those for coaxial phacoemulsification. This may be attributed to the absence of a sleeve, which places the incision tunnel in direct contact with the metal phaco tip.

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

    DEFF Research Database (Denmark)

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


    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...


    Institute of Scientific and Technical Information of China (English)

    刘宝国; 刘伟; 顾晋


    To investigate the feasibility and advantages of the unilateral big hockey stick incision in thyroid carcinoma. Method: Neck dissection using the unilateral big hockey stick incision was performed on 23 patients with thyroid carcinoma. Results: The big hockey stick incision results in a cosmetic scar which is barely visible and easily covered by hair or clothing, while it provides sufficient exposure of the operation field. A small area of marginal necrosis is occasionally seen at the apex of the skin flap due to preoperative radiotherapy. Conclusion: The unilateral big hockey stick incision has adequate surgical access, good healing of skin flaps, and a good cosmetic result.

  15. Safety of cesarean delivery through placental incision in patients with anterior placenta previa. (United States)

    Hong, Deok-Ho; Kim, Eugene; Kyeong, Kyu-Sang; Hong, Seung Hwa; Jeong, Eun-Hwan


    To demonstrate the safety of fetal delivery through placental incision in a placenta previa pregnancy. We examined the medical records of 80 women with singleton pregnancy diagnosed with placenta previa who underwent cesarean section between May 2010 and May 2015 at the Department of Obstetrics and Gynecology, Chungbuk National University Hospital. Among the women with placenta previa, those who did not have the placenta in the uterine incision site gave birth via conventional uterine incision, while those with anterior placenta previa or had placenta attached to the uterine incision site gave birth via uterine incision plus placental incision. We compared the postoperative hemoglobin level and duration of hospital stay for the mother and newborn of the two groups. There was no difference between the placental incision group and non-incision group in terms of preoperative and postoperative hemoglobin change, the amount of blood transfusions required by the mother, newborns with 1-min or 5-min Apgar scores below 7 points or showing signs of acidosis on umbilical cord blood gas analysis result of pH below 7.20. Moreover, neonatal hemoglobin levels did not differ between the two groups. Fetal delivery through placental incision during cesarean section for placenta previa pregnancy does not negatively influence the prognosis of the mother or the newborn, and therefore, is considered a safe surgical technique.

  16. Brain derived neurotrophic factor (BDNF contributes to the pain hypersensitivity following surgical incision in the rats

    Directory of Open Access Journals (Sweden)

    Zhang Jian-Yi


    Full Text Available Abstract Background The pathogenic role of brain derived neurotrophic factor (BDNF in the incisional pain is poorly understood. The present study explores the role of the BDNF in the incision-induced pain hypersensitivity. Methods A longitudinal incision was made in one plantar hind paw of isoflurane-anesthetized rats. Dorsal root ganglias (DRG and spinal cords were removed at various postoperative times (1–72 h. Expression pattern of BDNF was determined by immunohistochemistry and double-labeling immunofluorescence. Lidocaine-induced blockade of sciatic nerve function was used to determine the importance of afferent nerve activity on BDNF expression in the DRG and spinal cord after incision. BDNF antibody was administered intrathecally (IT or intraperitoneal (IP to modulate the spinal BDNF or peripheral BDNF after incision. Results After hind-paw incision, the BDNF was upregulated in the ipsilateral lumbar DRG and spinal cord whereas thoracic BDNF remained unchanged in response to incision. The upregulated BDNF was mainly expressed in the large-sized neurons in DRG and the neurons and the primary nerve terminals in the spinal cord. Sciatic nerve blockade prevented the increase of BDNF in the DRG and spinal cord. IT injection of BDNF antibody greatly inhibited the mechanical allodynia induced by incision whereas IP administration had only marginal effect. Conclusion The present study showed that incision induced the segmental upregulation of BDNF in the DRG and spinal cord through somatic afferent nerve transmission, and the upregulated BDNF contributed to the pain hypersensitivity induced by surgical incision.

  17. Activated conduction by small incision and moderate stimulation for treatment of cerebral palsy in 182 cases

    Institute of Scientific and Technical Information of China (English)

    Wenying Wang; Jianhua Shi; Mingjiang Yu; Dazhi Zhang


    BACKGROUND: Internationally, methods to treat cerebral palsy (CP) are basically the same, including correction of deformity with orthopaedic operation, selective posterior rhizotomy(SPR), rehabilitation therapy and so on. Domestic methods to treat CP are basically close to the international methods. Traditional Chinese medical therapies, such as, acupuncture and moxibustion, acupoint injection, massage and so on, also have good curative effects.OBJECTIVE: To observe the effect of activated conduction by small incision and moderate stimulation (ACSIMS) on limb function and living ability in patients with spastic CP at different degrees. DESIGN: Retrospective case analysis.SETTING: Department of Medical Education, Shanxi Medical College for Continuing Education. PARTICIPANTS: A total of 182 patients with CP, including 97 males and 85 females, aged 3 to 23 years, who received treatment in Beijing Haidian District Diaoyutai Hospital during October 1996 to September 2005, were involved in this trial. The involved patients met the diagnostic criteria proposed in 2004 National Special Seminar of Cerebral Palsy. According to typing criteria of CP purposed in 1990 Brioni International Conference, the involved patients were typed: 117 with spastic CP, 14 with involuntary movement CP, 19 with defective coordination CP, 5 with hypotonia CP and 27 with mixed type CP. The guardians of underage patients and adult patients themselves were all informed of the therapeutic regimens. METHODS: ①According to CP typing assessment quantitative criteria of Li, the involved patients were assigned from limb position, daily living and movement 3 aspects: mild 23, moderate 75, severe 62 and extremely severe 22. ② Operation methods: The lower limb of moderate spastic CP patient was taken as an example. A median incision or paramedian incision was made between L2 and S1, and it was also the first incision in lower limb. The secorid incision was made at the center of buttock or at the

  18. Fluvial Morphodynamics: advancing understanding using Multibeam Echo Sounders (MBES) (United States)

    Parsons, D. R.; Best, J. L.


    Accurately and reliably determining riverbed morphology is key to understanding linkages between flow fields, sediment transport and bed roughness in a range of aquatic environments, including large fluvial channels. Modern shallow-water multibeam echo sounder (MBES) systems are now allowing us to acquire bathymetric data at unprecedented resolutions that are millimetric in precision and centimetric in accuracy. Such systems, and the morphological resolution they can supply, are capable of revealing the complex three-dimensional patterns in riverbed morphology that are facilitating a holistic examination of system morphodynamics, at the field scale, that was unimaginable just a few years ago. This paper presents a range of MBES acquired examples to demonstrate how the methodological developments in this technology are leading to advances in our substantive understanding of large river systems. This includes examples that show linkages across scales, and in particular the morphodynamics of superimposed bedforms and bars revealed by such high-resolution data, which have broad implications for a range of applications, including flood prediction, engineering design and reconstructing ancient sedimentary environments.

  19. Compounding effects of sea level rise and fluvial flooding. (United States)

    Moftakhari, Hamed R; Salvadori, Gianfausto; AghaKouchak, Amir; Sanders, Brett F; Matthew, Richard A


    Sea level rise (SLR), a well-documented and urgent aspect of anthropogenic global warming, threatens population and assets located in low-lying coastal regions all around the world. Common flood hazard assessment practices typically account for one driver at a time (e.g., either fluvial flooding only or ocean flooding only), whereas coastal cities vulnerable to SLR are at risk for flooding from multiple drivers (e.g., extreme coastal high tide, storm surge, and river flow). Here, we propose a bivariate flood hazard assessment approach that accounts for compound flooding from river flow and coastal water level, and we show that a univariate approach may not appropriately characterize the flood hazard if there are compounding effects. Using copulas and bivariate dependence analysis, we also quantify the increases in failure probabilities for 2030 and 2050 caused by SLR under representative concentration pathways 4.5 and 8.5. Additionally, the increase in failure probability is shown to be strongly affected by compounding effects. The proposed failure probability method offers an innovative tool for assessing compounding flood hazards in a warming climate.

  20. Microbiological and geochemical characterization of fluvially deposited sulfidic mine tailings (United States)

    Wielinga; Lucy; Moore; Seastone; Gannon


    The fluvial deposition of mine tailings generated from historic mining operations near Butte, Montana, has resulted in substantial surface and shallow groundwater contamination along Silver Bow Creek. Biogeochemical processes in the sediment and underlying hyporheic zone were studied in an attempt to characterize interactions consequential to heavy-metal contamination of shallow groundwater. Sediment cores were extracted and fractionated based on sediment stratification. Subsamples of each fraction were assayed for culturable heterotrophic microbiota, specific microbial guilds involved in metal redox transformations, and both aqueous- and solid-phase geochemistry. Populations of cultivable Fe(III)-reducing bacteria were most prominent in the anoxic, circumneutral pH regions associated with a ferricrete layer or in an oxic zone high in organic carbon and soluble iron. Sulfur- and iron-oxidizing bacteria were distributed in discrete zones throughout the tailings and were often recovered from sections at and below the anoxic groundwater interface. Sulfate-reducing bacteria were also widely distributed in the cores and often occurred in zones overlapping iron and sulfur oxidizers. Sulfate-reducing bacteria were consistently recovered from oxic zones that contained high concentrations of metals in the oxidizable fraction. Altogether, these results suggest a highly varied and complex microbial ecology within a very heterogeneous geochemical environment. Such physical and biological heterogeneity has often been overlooked when remediation strategies for metal contaminated environments are formulated.

  1. Progress in and prospects for fluvial flood modelling. (United States)

    Wheater, H S


    Recent floods in the UK have raised public and political awareness of flood risk. There is an increasing recognition that flood management and land-use planning are linked, and that decision-support modelling tools are required to address issues of climate and land-use change for integrated catchment management. In this paper, the scientific context for fluvial flood modelling is discussed, current modelling capability is considered and research challenges are identified. Priorities include (i) appropriate representation of spatial precipitation, including scenarios of climate change; (ii) development of a national capability for continuous hydrological simulation of ungauged catchments; (iii) improved scientific understanding of impacts of agricultural land-use and land-management change, and the development of new modelling approaches to represent those impacts; (iv) improved representation of urban flooding, at both local and catchment scale; (v) appropriate parametrizations for hydraulic simulation of in-channel and flood-plain flows, assimilating available ground observations and remotely sensed data; and (vi) a flexible decision-support modelling framework, incorporating developments in computing, data availability, data assimilation and uncertainty analysis.

  2. Uncertainty analysis of fluvial outcrop data for stochastic reservoir modelling

    Energy Technology Data Exchange (ETDEWEB)

    Martinius, A.W. [Statoil Research Centre, Trondheim (Norway); Naess, A. [Statoil Exploration and Production, Stjoerdal (Norway)


    Uncertainty analysis and reduction is a crucial part of stochastic reservoir modelling and fluid flow simulation studies. Outcrop analogue studies are often employed to define reservoir model parameters but the analysis of uncertainties associated with sedimentological information is often neglected. In order to define uncertainty inherent in outcrop data more accurately, this paper presents geometrical and dimensional data from individual point bars and braid bars, from part of the low net:gross outcropping Tortola fluvial system (Spain) that has been subjected to a quantitative and qualitative assessment. Four types of primary outcrop uncertainties are discussed: (1) the definition of the conceptual depositional model; (2) the number of observations on sandstone body dimensions; (3) the accuracy and representativeness of observed three-dimensional (3D) sandstone body size data; and (4) sandstone body orientation. Uncertainties related to the depositional model are the most difficult to quantify but can be appreciated qualitatively if processes of deposition related to scales of time and the general lack of information are considered. Application of the N0 measure is suggested to assess quantitatively whether a statistically sufficient number of dimensional observations is obtained to reduce uncertainty to an acceptable level. The third type of uncertainty is evaluated in a qualitative sense and determined by accurate facies analysis. The orientation of sandstone bodies is shown to influence spatial connectivity. As a result, an insufficient number or quality of observations may have important consequences for estimated connected volumes. This study will give improved estimations for reservoir modelling. (author)

  3. Characterization of fluvial sedimentology for reservoir simulation modeling

    Energy Technology Data Exchange (ETDEWEB)

    Henriquez, A.; Tyler, K.J.; Hurst, A. (Statoil, Stavanger (NO))


    This paper presents a critical study of 3D stochastic simulation of a fluvial reservoir and of the transfer of the geological model to a reservoir simulation grid. The stochastic model is conditioned by sand-body thickness and position in wellbores. Geological input parameters-sand-body orientation and width/thickness ratios-are often difficult to determine, and are invariably subject to interpretation. Net/gross ratio (NGR) and sand-body thickness are more easily estimated. Sand-body connectedness varies, depending on the modeling procedure; however, a sedimentary process-related model gives intermediate values for connectedness between the values for a regular packing model and the stochastic model. The geological model is transferred to a reservoir simulation grid by use of transmissibility multipliers and an NGR value for each block. The transfer of data smooths out much of the detailed geological information, and the calculated recovery factors are insensitive to the continuity measured in the geological model. Hence, the authors propose improvements to the interface between geological and reservoir simulation models.

  4. Metabolism of mineral-sorbed organic matter depends upon microbial lifestyle in fluvial ecosystems


    Hunter, William Ross; Niederdorfer, Robert; Gernand, Anna; Veuger, Bart; Prommer, Judith; Mooshammer, Maria; Wanek, Wolfgang; Battin, Tom J.


    In fluvial ecosystems mineral erosion, carbon (C) and nitrogen (N) fluxes are linked via organo-mineral complexation, where dissolved organic molecules bind to mineral surfaces. Biofilms and suspended aggregates represent major aquatic microbial lifestyles whose relative importance changes predictably through fluvial networks. We tested how organo-mineral sorption affects aquatic microbial metabolism, using organo-mineral particles containing a mix of 13C, 15N-labelled amino acids. We traced ...

  5. Comparison of the incisions for the open surgical treatment of gluteal muscle contracture. (United States)

    Xu, Jian; Geng, Xiang; Muhammad, Hassan; Wang, Xu; Huang, Jia-Zhang; Zhang, Chao; Ma, Xin


    Gluteal muscle contracture is not very common, but cases are still seen in China. Open surgical treatment is considered as an efficient method to treat this disease. However, the type of incision that can provide best results is yet to be determined. The authors therefore compared various incisions to determine the better one. In this retrospective study, patients who underwent surgery with a traverse straight incision, a curved incision, a longitudinal straight incision, or an 'S'-shaped incision above the greater trochanter were enrolled and divided into four groups: A, B, C, and D. In each group, the patients were divided into different levels according to a specific standard. The four groups were compared in terms of incision length, postoperative drainage amounts, wound healing rates, visual analog scale scores, and improvement in the degree of range of motion (ROM). During the follow-up period, the validity of the results, complications, and recurrent cases were evaluated. In our study, incision length and visual analog scale score of the four groups showed no significant differences (P>0.05). Wound healing rates, drainage amount, improvement in ROM, validity of the results, and recurrences in group D were significantly the best (P<0.05). No significant differences in wound healing rates, drainage amount, and improvement in ROM were found in groups A, B, and C. In terms of validity of the results and 1-year recurrence, no significant difference was observed between groups A and B; however, these factors were better than those in group C. We concluded that the 'S'-shaped incision above the greater trochanter is the most efficient among the incisions described in this study. This incision has the following advantages: clear exposure, less damage, high safety rate, excellent results, and low recurrence rate.

  6. Our First Experience With Negative Pressure Incision Management System Implemented on the Clean Surgical Incision in the Renal Transplantation Recipient: A Case Report. (United States)

    Bozkurt, B; Tokac, M; Dumlu, E G; Yalcin, A; Kilic, M


    Multiple comorbidities and environmental factors increase the complications of incisional wounds in patients. It was demonstrated in previous prospective and randomized studies that negative pressure wound therapy (NPWT) reduced wound infection and other complications in clean, closed surgical incisions. In this case report, the Prevena incision management system was implemented on the clean, closed surgical incision of a 52-year-old female patient, who was given a renal transplantation from cadaver postoperatively in the operating theater. It was removed from the patient on the fifth day after the operation. Following the removal of Prevena, the wound and surrounding skin of the patient were observed. Wound healing was complete, and no skin lesion or tool-related complication was found around the wound due to NPWT. The Prevena NPWT system can be conveniently and safely implemented on the operational incision in renal transplant recipients in order to prevent surgical wound complications.

  7. Repair of congenital diaphragmatic hernias through umbilical skin incisions. (United States)

    Uehara, Shuichiro; Usui, Noriaki; Kamiyama, Masafumi; Masahata, Kazunori; Nara, Keigo; Ueno, Takehisa; Soh, Hideki; Oue, Takaharu; Fukuzawa, Masahiro


    The use of thoracoscopy and laparoscopy in the treatment of congenital diaphragmatic hernias (CDHs) has been recently reported; however, the use of these procedures still remains controversial due to CO2 insufflation and limited working space. In addition, because of difficult techniques, it has not been widely accepted. Among CDH patients, mild cases whose lung is not hypoplastic, and not associated with persistent pulmonary hypertension of the neonate (PPHN) often develop small defects in the diaphragm that can be repaired using "direct closure." Because direct closure does not require as wide an operative field as that needed for patch closure, we repaired CDH through umbilical skin windows in two neonates with mild CDH to minimize the wounds. With the creation of additional radical small incisions, the surgeries were successfully performed without any intra- or postoperative complications, and the wounds were cosmetically pleasing. The repair of CDHs through umbilical skin windows is a feasible and useful approach in neonates with mild CDH.

  8. Single incision laparoscopic splenectomy, technical aspects and feasibility considerations. (United States)

    Cabras, Francesco; Fabrizio, Lazzara; Bracale, Umberto; Andreuccetti, Jacopo; Pignata, Giusto


    Minimally invasive techniques have been introduced to reduce morbidity related to standard laparoscopic procedures. One such approach is laparoendoscopic single-site surgery. The aim of the study was to present our initial clinical experience of using this technique for elective splenectomy. We carried out single access laparoscopic splenectomy (SALS) for an 8 cm cystic lesion of the spleen, involving the hilum, on a 38-year-old woman. The procedure was performed with a single-port device (4-channel) via a 2.5-cm umbilical incision. A flexible 5-mm optic and straight laparoscopic instruments were used. The operative time was 75 min. There was no blood loss. No complications were observed. The postoperative period was uneventful. Although substantial development of the instruments and skills is needed, this SALS technique appears to be feasible and safe. Nevertheless, further experience and observations are necessary.

  9. Single-incision laparoscopic splenectomy with innovative gastric traction suture

    Directory of Open Access Journals (Sweden)

    Srikanth G


    Full Text Available Laparoscopic splenectomy is now the gold standard for patients with idiopathic thrombocytopenic purpura (ITP undergoing splenectomy. There are a few reports in literature on single-incision laparoscopic (SIL splenectomy. Herein, we describe a patient undergoing SIL splenectomy for ITP without the use of a disposable port device. We report a 20-year-old female patient with steroid-refractory ITP having a platelet count of 14,000/cmm who underwent a SIL splenectomy. Dissection was facilitated by the use of a single articulating grasper and a gastric traction suture and splenic vessels were secured at the hilum with an endo-GIA stapler. She made an uneventful postoperative recovery and was discharged on the second postoperative day. She is doing well with no visible scar at 8-month follow-up.

  10. Nucleus management in manual small incision cataract surgery by phacosection

    Directory of Open Access Journals (Sweden)

    Ravindra M


    Full Text Available Nucleus management is critical in manual small incision cataract surgery (MSICS, as the integrity of the tunnel, endothelium and posterior capsule needs to be respected. Several techniques of nucleus management are in vogue, depending upon the specific technique of MSICS. Nucleus can be removed in toto or bisected or trisected into smaller segments. The pressure in the eye can be maintained at the desired level with the use of an anterior chamber maintainer or kept at atmospheric levels. In MSICS, unlike phacoemulsification, there is no need to limit the size of the tunnel or restrain the size of capsulorrhexis. Large well-structured tunnels and larger capsulorrhexis provide better control on the surgical maneuvers. Safety and simplicity of MSICS has made it extremely popular. The purpose of this article is to describe nucleus management by phacosection in MSICS.

  11. A case of keratitis associated with limbal relaxing incision

    Directory of Open Access Journals (Sweden)

    Aravind Haripriya


    Full Text Available We report a case of keratitis associated with limbal relaxing incision (LRI. The patient presented with progressive loss of vision with best-corrected visual acuity 20/40. Immature cataract with 1.43D against the rule astigmatism was noted. Prophylactic topical antibiotic was administered before surgery. He underwent uneventful phacoemulsification with intraocular lens implantation with LRI. On the 33rd postoperative day (POD, he presented with infiltrate along LRI site with mild iritis. Corneal scraping was positive for Staphylococcus aureus. After the treatment with topical moxifloxacin and fortified cefazolin, the infiltrate started to resolve. On the 50th POD, the corneal infection was resolved with marked thinning at LRI site.

  12. A case of keratitis associated with limbal relaxing incision (United States)

    Haripriya, Aravind; Smita, Anand


    We report a case of keratitis associated with limbal relaxing incision (LRI). The patient presented with progressive loss of vision with best-corrected visual acuity 20/40. Immature cataract with 1.43D against the rule astigmatism was noted. Prophylactic topical antibiotic was administered before surgery. He underwent uneventful phacoemulsification with intraocular lens implantation with LRI. On the 33rd postoperative day (POD), he presented with infiltrate along LRI site with mild iritis. Corneal scraping was positive for Staphylococcus aureus. After the treatment with topical moxifloxacin and fortified cefazolin, the infiltrate started to resolve. On the 50th POD, the corneal infection was resolved with marked thinning at LRI site. PMID:28112139

  13. Transcriptomic analysis of incised leaf-shape determination in birch. (United States)

    Mu, Huaizhi; Lin, Lin; Liu, Guifeng; Jiang, Jing


    Plant researchers have focused much attention on leaf shape because of its importance in the identification. To evaluate the impact of intraspecies leaf-shape variation on the transcriptome, a series of Betula pendula 'Dalecarlica' and B. pendula saplings were generated through tissue culture. The leaf shapes and transcriptomes of B. pendula 'Dalecarlica' clones were compared with those of B. pendula clones. The leaf shape of B. pendula 'Dalecarlica' was incised and that of B. pendula was ovate. Transcriptome data revealed numerous changes in gene expression between B. pendula 'Dalecarlica' and B. pendula, including upregulation of 8767 unigenes and downregulation of 8379 unigenes in B. pendula 'Dalecarlica'. A pathway analysis revealed that the transport and signal transduction of auxin were altered in 'Dalecarlica', which may have contributed to its altered leaf shape. These results shed light on variation in birch leaf shape and help identify important genes for the genetic engineering of birch trees. © 2013.

  14. Late Quaternary Incisions and Related Shallow Subsurface Stratigraphy on the New Jersey Mid-Outer Shelf: Preliminary Results from Ultra-High Resolution Chirp Sonar Images - Part II (United States)

    Fulthorpe, C. S.; Goff, J. A.; Austin, J. A.; Gulick, S. P.; Nordfjord, S.


    High-resolution (1-15 kHz), shallow-penetration (~50 m), deep-towed chirp seismic profiles were collected on the New Jersey mid- and outer-shelf in August-September 2001 (R/V Endeavor cruise 359) in support of ONR's Geoclutter program. Geoclutter goals are to understand and predict acoustic scattering from the seafloor and the shallow sub-seafloor in order to distinguish man-made objects from naturally occurring features ("geological clutter") on sonar returns. The 2001 chirp survey focused on previously identified buried channels, of presumed fluvial origin, which may contribute to geoclutter. These channels are inferred to have formed during the sea-level lowstand of the last glacial maximum, and their fill likely constitutes a high-resolution record of the latest transgression. This survey represents the most comprehensive mapping to date of shallowly buried fluvial channels in a continental shelf setting. To allow robust mapping of channel systems, the survey maintained dense seismic profile spacings, mainly 200-900 m, but with some at 50 m. We focus on the southern portion of the survey area, where three channel systems are identified within an 8.6 x 10.2 km grid. The northernmost of these lies sufficiently within the survey area to be mapped in detail. Its channels are mainly V-shaped, up to 350 m wide and 12 m deep. Present water depth is ~80 m and channel flanks are truncated by the seafloor, except in a small area where an overlying unconformity truncating channel flanks is preserved. Some channels are truncated by erosional seafloor scour pits, mapped earlier with high-resolution multibeam data. Channel fill stratigraphy indicates multiple stages of incision and filling. Interfluves comprise up to ~20 m of a seismically transparent facies overlying stratified sediment. Grab samples contain medium-to-coarse sands, but such surficial sediments may not be entirely representative of the transparent facies. The contact with the stratified sediment is irregular

  15. Single-incision retroperitoneoscopic adrenalectomy: a North American experience. (United States)

    Sho, Shonan; Yeh, Michael W; Li, Ning; Livhits, Masha J


    Endoscopic adrenalectomy is currently performed using multiple ports placed either transabdominally or retroperitoneally. We report our initial experience with single-incision retroperitoneoscopic adrenalectomy (SIRA). A prospective database of patients undergoing adrenalectomy from December 2013 through March 2016 was analyzed. We adopted conventional retroperitoneoscopic adrenalectomy (CORA) in December 2013 and transitioned to SIRA in March 2015. SIRA was performed using three trocars placed through a single 2-cm incision below the 12th rib. Clinical characteristics and outcomes were compared between patients undergoing SIRA and CORA. One hundred and five adrenalectomies were performed in 102 patients: 34 laparoscopic transperitoneal, 24 CORA, 37 SIRA and 7 open. The SIRA and CORA groups were similar with respect to clinical characteristics (SIRA vs. CORA: mean BMI 27.0 vs. 28.8 kg/m(2), maximum BMI 38.9 vs. 44.3 kg/m(2); mean nodule size 3.2 vs. 3.2 cm, maximum nodule size 8.0 vs. 6.0 cm). One patient undergoing SIRA required placement of an additional 5-mm port because of extensive adhesions. No patients who underwent SIRA or CORA required conversion to open adrenalectomy. There were no deaths, and blood loss remained CORA (105 vs. 92 min, P = 0.26). In multivariable linear regression analysis, nodule size > 5 cm (effect = 1.75, P CORA and may be applied to technically challenging cases involving obese patients or large nodules. The use of three ports allows for two-handed dissection, which may shorten the learning curve for many surgeons.

  16. Evolution of cataract surgery: Smaller incision - less complications

    Directory of Open Access Journals (Sweden)

    Draganić Vladimir


    Full Text Available Background/Aim. Cataract surgery has become one of the safest procedures in medicine thanks to advances in technology and surgical techniques. Although minimal, we still witness different complications. The aim of this study was to compare visual outcome and complication rate in different techniques of cataract surgery, ie in cataract surgeries with various corneal incision width. Methods. The study included 3,457 consecutive patients, ie 4,670 eyes that had undergone cataract surgery. The used surgical techniques were: extracapsular cataract extraction, phacoemulsification/ forceps IOL implantation, phacoemulsification/ injector IOL implantation, microincision cataract surgery (MICS. Patient follow up was 6 months. Patients were evaluated for: visual aquity, corneal astigmatism, cellular reaction in the anterior chamber, IOL position. Results. Uncorrected visual aquity 30 days postoperatively was ≥ 0.5 in 30% of the eyes - ECCE; 54.7% of the eyes - phacoemulsification/forceps IOL implantation; 63.0% of the eyes - phacoemulsification/injector IOL implantation; 5/8 of the eyes - MICS. Endophthalmitis was detected in 0.15% of the eyes - ECCE and 0.1% of the eyes - phacoemulsification/forceps IOL implantation. In eyes with phacoemulsification/injector IOL implantation or microincision cataract surgery (MICS there were no cases of endophthalmitis. After a 6-month period intraocular lens were dislocated in 7.2% of the eyes - ECCE, and 0.6% of the eyes - phacoemulsification/PMMA IOL. There was no IOL dislocation in other surgical techniques. Conclusion. Shorter corneal incision implies less complications, less operative trauma, faster visual rehabilitation and better visual outcome.

  17. [Evolution of cataract surgery: smaller incision--less complications]. (United States)

    Draganić, Vladimir; Vukosavljević, Miroslav; Milivojević, Milorad; Resan, Mirko; Petrović, Nenad


    Cataract surgery has become one of the safest procedures in medicine thanks to advances in technology and surgical techniques. Although minimal, we still witness different complications. The aim of this study was to compare visual outcome and complication rate in different techniques of cataract surgery, ie in cataract surgeries with various corneal incision width. The study included 3,457 consecutive patients, ie 4,670 eyes that had undergone cataract surgery. The used surgical techniques were: extracapsular cataract extraction, phacoemulsification/forceps IOL implantation, phacoemulsification/injector IOL implantation, microincision cataract surgery (MICS). Patient follow up was 6 months. Patients were evaluated for: visual aquity, corneal astigmatism, cellular reaction in the anterior chamber, IOL position. Uncorrected visual aquity 30 days postoperatively was > or = 0.5 in 30% of the eyes - ECCE; 54.7% of the eyes - phacoemulsification/forceps IOL implantation; 63.0% of the eyes - phacoemulsification/injector IOL implantation; 5/8 of the eyes - MICS. Endophthalmitis was detected in 0.15% of the eyes - ECCE and 0.1% of the eyes - phacoemulsification/forceps IOL implantation. In eyes with phacoemulsification/injector IOL implantation or microincision cataract surgery (MICS) there were no cases of endophthalmitis. After a 6-month period intraocular lens were dislocated in 7.2% of the eyes - ECCE, and 0.6% of the eyes - phacoemulsification/PMMA IOL. There was no IOL dislocation in other surgical techniques. Shorter corneal incision implies less complications, less operative trauma, faster visual rehabilitation and better visual outcome.

  18. Disturbance of fluvial gravel substrates by signal crayfish (Pacifastacus leniusculus) (United States)

    Johnson, Matthew; Rice, Stephen; Reid, Ian


    The reworking of substrates by organisms, termed bioturbation, is considered a fundamental processes in marine and terrestrial environments but has remained relatively unstudied in fluvial environments. This studies looks at the bioturbation of fluvial gravel substrates by signal crayfish, an internationally important invasive species. We investigated the impact of signal crayfish activity in a laboratory flume. Bioturbation by crayfish on both loose arrangements of gravel and water-worked surfaces were studied and two sizes of narrowly-graded gravel were used; 11 - 16 mm and 16 - 22 mm. A laser scanner was used to obtain high resolution digital elevation models (DEMs) of gravel surfaces before and after crayfish activity. These DEMs were used to quantify topographic and structural changes to the surfaces due to the activity of crayfish. It was found that crayfish moved substantial quantities of material from all surfaces within six hours of introduction. The majority of the disturbance was associated with small scale (≤ 1 median grain diameter) movements of surface grains due to walking and foraging by crayfish. This textural change resulted in a structural alteration to the substrate surface. After six hours of crayfish activity, there was a 14% reduction in the imbrication of the grains from water-worked surfaces. Crayfish also constructed shallow pits and heaped excavated material into a series of mounds around its edge. Crayfish would always posture in pits in the same way. They would fold their vulnerable tails under their body and place their claws in front of their heads. When in pits crayfish predominately orientated themselves so they were facing an upstream direction. This implies that crayfish dig pits in order to streamline their bodies in the flow and lower their protrusion. Although pits and mounds contributed a relatively small proportion to the overall disturbance of substrates, they significantly increased the roughness of substrates. Pit and

  19. OSL age determinations of Pleistocene fluvial deposits in Central Amazonia

    Directory of Open Access Journals (Sweden)

    Emílio A.A. Soares


    Full Text Available Absolute dating methods have been used in chronological studies of geological processes and sedimentary units of Quaternary age in Central Amazonia, Brazil. Although radiocarbon dating has been very useful in archaeological research and soil studies, the temporal interval of this method is inefficient in evaluating the sedimentation aspects and geological events from the beginning of the Quaternary in the Amazon basin. The use of crystal luminescence dating has been one of the most promising tool for determining the absolute dating of Quaternary deposits in the Amazonian region. Optically stimulated luminescence (OSL dating, following the MAR and SAR protocols, in a tectonic-sedimentary study of Quaternary fluvial deposits in the confluence area of the Negro and Solimões rivers, indicated ages from 1.3 (Holocene to about 67.4 kyears (Late Pleistocene for these sediments. Low radioactive isotope concentrations were found about 2ppm for 235U and 238U; 5ppm for 232Th; and the 40K concentrations were almost zero. A comparison was made between MAR and SAR protocols taking into account the fluvial depositional process.Métodos de datação absoluta têm sido usados em estudos cronológicos de processos geológicos e unidades sedimentares de idade quaternária na Amazônia Central, Brasil. Embora as datações pelo 14C tenham sido muito úteis na pesquisa arqueológica e estudos de solos, o intervalo de tempo abrangido por este método é ineficiente para avaliar aspectos da sedimentação e eventos geológicos do início do Quaternário na bacia Amazônica. O uso da datação por luminescência de cristais tem sido uma das ferramentas mais promissoras para a determinação da idade absoluta de depósitos quaternários na região amazônica. A datação por luminescência opticamente estimulada (LOE, seguindo os protocolos MAR e SAR, em um estudo tectono-sedimentar de depósitos aluviais quaternários da área de confluência dos rios Negro e Solim

  20. Palaeo-fluvial origin for Jakobshavn Isbrae catchment (United States)

    Cooper, Michael; Michaelides, Katerina; Siegert, Martin; Bamber, Jonathan


    Subglacial topography exerts strong controls on ice dynamics, influencing the nature of ice flow, and modulating the distribution of basal waters and sediment. Bed geometry can provide a long-term record of geomorphic processes, allowing insight into landscape evolution, the origin of which, in some cases, can pre-date ice sheet inception. Here, we present evidence from ice-penetrating radar data for a large dendritic drainage network, radiating inland from Jakobshavn Isbrae, Greenland's largest outlet glacier. The size of the drainage basin is ~450,000 km-squared, comparable with that of the Ohio River in the United States, and accounts for ~20% of the land area of Greenland. Topographic, and basin morphometric analysis of isostatically compensated (ice-free) bedrock topography suggests that this catchment pre-dates ice sheet inception (~3.5 Ma), and will have been instrumental in influencing flow from the island's interior to the margin. The geological setting, and glacial history of Greenland lends itself well to the preservation of such landscapes; the island is dominated by erosion-resistant, Precambrian crystalline rocks with few sedimentary deposits, and has only been extensively ice-covered for ~3.5 million years (Ma). Despite this, most analysis of subglacial geomorphology, and of 'pre-glacial' landscapes, has been focused on Antarctica (e.g. the Ellsworth Subglacial Highlands and, 'pre-glacial erosional surfaces' of the West Antarctic Ice Sheet (WAIS)), with little consideration for such associations in Greenland. However, a large subglacial 'mega-canyon' in northern Greenland, thought to of palaeo-fluvial origin, has recently been discovered.

  1. Fluvial erosion and post-erosional processes on Titan (United States)

    Jaumann, R.; Brown, R.H.; Stephan, K.; Barnes, J.W.; Soderblom, L.A.; Sotin, C.; Le, Mouelic S.; Clark, R.N.; Soderblom, J.; Buratti, B.J.; Wagner, R.; McCord, T.B.; Rodriguez, S.; Baines, K.H.; Cruikshank, D.P.; Nicholson, P.D.; Griffith, C.A.; Langhans, M.; Lorenz, R.D.


    The surface of Titan has been revealed by Cassini observations in the infrared and radar wavelength ranges as well as locally by the Huygens lander instruments. Sand seas, recently discovered lakes, distinct landscapes and dendritic erosion patterns indicate dynamic surface processes. This study focus on erosional and depositional features that can be used to constrain the amount of liquids involved in the erosional process as well as on the compositional characteristics of depositional areas. Fluvial erosion channels on Titan as identified at the Huygens landing site and in RADAR and Visible and Infrared Mapping Spectrometer (VIMS) observations have been compared to analogous channel widths on Earth yielding average discharges of up to 1600 m3/s for short recurrence intervals that are sufficient to move centimeter-sized sediment and significantly higher discharges for long intervals. With respect to the associated drainage areas, this roughly translates to 1-150 cm/day runoff production rates with 10 years recurrence intervals and by assuming precipitation this implies 0.6-60 mm/h rainfall rates. Thus the observed surface erosion fits with the methane convective storm models as well as with the rates needed to transport sediment. During Cassini's T20 fly-by, the VIMS observed an extremely eroded area at 30?? W, 7?? S with resolutions of up to 500 m/pixel that extends over thousands of square kilometers. The spectral characteristics of this area change systematically, reflecting continuous compositional and/or particle size variations indicative of transported sediment settling out while flow capacities cease. To account for the estimated runoff production and widespread alluvial deposits of fine-grained material, release of area-dependent large fluid volumes are required. Only frequent storms with heavy rainfall or cryovolcanic induced melting can explain these erosional features. ?? 2008 Elsevier Inc.

  2. Coupling within Fluvial Geomorphic Systems:Spatial and Temporal Implications

    Institute of Scientific and Technical Information of China (English)


    Coupling within fluvialsystems relates to the connectivity between the various components of the system. It can be viewed at several scales from local scales of hillslope-to-channel and reachto-reach coupling, to larger scales of zonai coupling between the major functional zones of the fluvial system, and to the scale of regional coupling. Coupling influences how the system responds toenvironmental change and how the effects of environmental change are propagated through the system. This paper provides a review, based largely on previously published work, of the couplingconcept, and how the effective temporal scales vary with the spatial scale of coupling. Local scalecoupling is considered through the hillslope-to-chiannel coupling in the Howgill Fells, northwestEngland, observed over a 30-year monitoring period, together with examples from badlands inSpain, and reach-to-reach coupling on the Rlver Dane, northwest England. At the zonal scale therelative influence of climatic and base-level chunge on coupling through dry-region alluvial fans isconsidered on fan systems in Spain, Nevada, and UAE/Oman. For large scale reg~nal coupling,the response of the Tabernas basih, southeast Spain to tectonic uplift, is examined. The factors in-fluencing coupling mechanisms vary with temporal and spatial scales. At the hillslope-to-channelscale the significant factors are the magnitude and frequency characteristics of sediment generationand removal mechanisms within the context of progressive morphological change. Effectivetimescales range from the individual event to decadal timescales. At the zonal scale, that of allu-vial fans, the significant factors are climatic change, and particularly in the appropriate morpho-logical setting, base-level change. Effective timescales are of the order of hundreds to thousands ofyears. At the regional scale, the response to tectonic uplift may take >100 ka to be transmitted4hcoughthe drainage basin.

  3. Dynamic LiDAR-NDVI classification of fluvial landscape units (United States)

    Ramírez-Núñez, Carolina; Parrot, Jean-François


    The lower basin of the Coatzacoalcos River is a wide floodplain in which, during the wet season, local and major flooding are distinguished. Both types of floods, intermittent and regional, are important in terms of resources; the regional flood sediments enrich the soils of the plains and intermittent floods allow obtaining aquatic resources for subsistence during the heatwave. In the floodplain different abandoned meanders and intermittent streams are quickly colonized by aquatic vegetation. However, from the 1990s, the Coatzacoalcos River floodplain has important topographic changes due to mining, road and bridges construction; erosion and sedimentation requires continuous parcel boundaries along with the increasing demand of channel reparation, embankments, levees and bridges associated to tributaries. NDVI data, LiDAR point cloud and various types of flood simulations taking into account the DTM are used to classify the dynamic landscape units. These units are associated to floods in relation with water resources, agriculture and livestock. In the study area, the first returns of the point cloud allow extracting vegetation strata. The last returns correspond to the bare earth surface, especially in this area with few human settlements. The surface that is not covered by trees or by aquatic vegetation, correspond to crops, pastures and bare soils. The classification is obtained by using the NDVI index coupled with vegetation strata and water bodies. The result shows that 47.96% of the area does not present active vegetation and it includes 31.53% of bare soils. Concerning the active vegetation, pastures, bushes and trees represent respectively 25.59%, 11.14% and 13.25%. The remaining 1.25% is distributed between water bodies with aquatic vegetation, trees and shrubs. Dynamic landscape units' classification represents a tool for monitoring water resources in a fluvial plain. This approach can be also applied to forest management, environmental services and

  4. Comparison of penetrating keratoplasty performed with a femtosecond laser zig-zag incision versus conventional blade trephination. (United States)

    Farid, Marjan; Steinert, Roger F; Gaster, Ronald N; Chamberlain, Winston; Lin, Amy


    To evaluate visual outcomes and astigmatism in patients who underwent penetrating keratoplasty (PK) with 2 different incision techniques. Retrospective comparison of a consecutive surgical series. Fifty-seven consecutive patients who underwent PK at the University of California, Irvine, academic referral practice. A comparison of 49 eyes of 43 patients that underwent femtosecond laser zig-zag incision pattern PK versus 17 eyes of 14 patients that underwent conventional Barron suction trephination PK performed contemporaneously. All PKs were closed with an identical, 24-bite running nylon suture technique. Topographically determined astigmatism, best spectacle-corrected visual acuity (BSCVA), and recovery of full visual potential. The postoperative follow-up ranged from 1 to 12 months. There was a significant difference in average astigmatism between the groups at postoperative month 1 (P = 0.013) and 3 (P = 0.018). By month 3, the average astigmatism was 3 diopters (D) in the zig-zag group and 4.46 D in the conventional group. Of the patients with normal macular and optic nerve function (n(ZZ) = 32; n(con) = 14), a significant difference in BSCVA was seen at month 1 (P = 0.0003) and month 3 (P = 0.006) with 81% of the zig-zag group versus 45% of the conventional group achieving BSCVA of > or =20/40 by month 3 (P = 0.03). The femtosecond laser generated zig-zag-shaped incision results in a more rapid recovery of BSCVA and induces less astigmatism compared with conventional blade trephination PK. Proprietary commercial disclosure may be found after the references.

  5. Systematic review: open, small-incision or laparoscopic cholecystectomy for symptomatic cholecystolithiasis.

    NARCIS (Netherlands)

    Keus, F.; Gooszen, H.G.; Laarhoven, C.J.H.M. van


    BACKGROUND: Laparoscopic cholecystectomy has become the method of choice for gallbladder removal, although evidence of superiority over open and small-incision cholecystectomy is lacking. AIM: To compare the effects of open, small-incision and laparoscopic cholecystectomy techniques for patients wit

  6. 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)


    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 i

  7. Systematic review: open, small-incision or laparoscopic cholecystectomy for symptomatic cholecystolithiasis

    DEFF Research Database (Denmark)

    Keus, F; Gooszen, H G; Van Laarhoven, C J H M


    Laparoscopic cholecystectomy has become the method of choice for gallbladder removal, although evidence of superiority over open and small-incision cholecystectomy is lacking.......Laparoscopic cholecystectomy has become the method of choice for gallbladder removal, although evidence of superiority over open and small-incision cholecystectomy is lacking....

  8. Systematic review : open, small-incision or laparoscopic cholecystectomy for symptomatic cholecystolithiasis

    NARCIS (Netherlands)

    Keus, F.; Gooszen, H. G.; Van Laarhoven, C. J. H. M.


    Laparoscopic cholecystectomy has become the method of choice for gallbladder removal, although evidence of superiority over open and small-incision cholecystectomy is lacking. To compare the effects of open, small-incision and laparoscopic cholecystectomy techniques for patients with symptomatic cho

  9. Randomized clinical trial of single- versus multi-incision laparoscopic cholecystectomy

    DEFF Research Database (Denmark)

    Jørgensen, Lars Nannestad; Rosenberg, J; Al-Tayar, H;


    BACKGROUND: There are no randomized studies that compare outcomes after single-incision (SLC) and conventional multi-incision (MLC) laparoscopic cholecystectomy under an optimized perioperative analgesic regimen. METHODS: This patient- and assessor-blinded randomized three-centre clinical trial c...

  10. Double incision wound healing bioassay using Hamelia patens from El Salvador. (United States)

    Gomez-Beloz, Alfredo; Rucinski, James C; Balick, Michael J; Tipton, Camille


    Hamelia patens Jacq. (Rubiaceae) has received little attention in the laboratory for its wound healing ability even though it is commonly used as a treatment for wounds throughout Central America. A double incision wound healing bioassay was carried out with a crude extract of Hamelia patens collected from El Salvador. Animals were divided into three groups. Group I (n = 14) had the left incision treated with 5% (w/w) Hamelia patens and the contralateral side with petroleum jelly (PJ). Group II (n = 14) had the left incision treated with 10% (w/w) ointment and the contralateral side with petroleum jelly. Group III (n = 10) had the left incision treated with petroleum jelly and the contralateral side left untreated. Breaking strength of the incisions was measured on day 7 and day 12. For Groups I and II, there was no significant difference between treatment and control incisions at day 7. On day 12, there was a significant difference between the treated and control incisions for Groups I and II. There was no significant difference between petroleum jelly and untreated incisions for Group III on day 7 and day 12. Hamelia patens does increase breaking strength of wounds significantly more than the control group. Further wound healing studies of this plant are warranted.

  11. 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


    , 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...

  12. Vertical intra-areolar incision in dual-plane breastaugmentation mammaplasty

    Institute of Scientific and Technical Information of China (English)

    LONG Xiao; ZENG Ang; ZHANG Hai-lin; QIAO Qun


    Objective To investigate the use of vertical intra-areolar incision in dual plane breast augmentation.Methods Fifteen cases received dual plane breast augmentation with vertical intra-areola incision in our hospital from January 2008 to December 2008.Breast gland was cut vertically in the upper part and pectoralis major muscle was separated according to the direction of the muscle fiber.Then the pectoralis major muscle was partially amputated at the starting point.Finally the implant was placed partially under the breast gland and partially under the pectoralis major muscle.Results The follow-up of more than one year showed all cases healed well and the incisions were concealed except one case who suffered delayed healing of the wound and depigmentation of the incision.Conclusion Vertical intra-areolar incision in dual plane breast augmentation is an easily-performed and feasible method and leaves less scar post operation.

  13. The lazy lateral incision: an innovative approach to the skin-sparing mastectomy. (United States)

    Dutton, Walter; Ghareeb, Paul A; McClellan, W Thomas


    The skin-sparing mastectomy has many advantages over a simple mastectomy, including preservation of the native breast skin, inframammary fold, and improved aesthetics for immediate reconstruction. The traditional transverse elliptical access incision is anterior on the breast mound, requires a second incision for previous biopsy sites, and provides restricted access to the axilla. We describe a novel mastectomy incision that improves scar appearance, improves access to the axillary contents, and reduces skin flap retraction. This incision starts at the nipple-areolar complex and extends laterally in a curvilinear fashion toward the axilla incorporating the biopsy scar along the way. This simple sinusoidal design results in an aesthetically superior alternative to the traditional linear mastectomy incision.

  14. Fluvial carbon export from a lowland Amazonian rainforest in relation to atmospheric fluxes (United States)

    Vihermaa, Leena E.; Waldron, Susan; Domingues, Tomas; Grace, John; Cosio, Eric G.; Limonchi, Fabian; Hopkinson, Chris; Rocha, Humberto Ribeiro; Gloor, Emanuel


    We constructed a whole carbon budget for a catchment in the Western Amazon Basin, combining drainage water analyses with eddy covariance (EC) measured terrestrial CO2 fluxes. As fluvial C export can represent permanent C export it must be included in assessments of whole site C balance, but it is rarely done. The footprint area of the flux tower is drained by two small streams ( 5-7 km2) from which we measured the dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), particulate organic carbon (POC) export, and CO2 efflux. The EC measurements showed the site C balance to be +0.7 ± 9.7 Mg C ha-1 yr-1 (a source to the atmosphere) and fluvial export was 0.3 ± 0.04 Mg C ha-1 yr-1. Of the total fluvial loss 34% was DIC, 37% DOC, and 29% POC. The wet season was most important for fluvial C export. There was a large uncertainty associated with the EC results and with previous biomass plot studies (-0.5 ± 4.1 Mg C ha-1 yr-1); hence, it cannot be concluded with certainty whether the site is C sink or source. The fluvial export corresponds to only 3-7% of the uncertainty related to the site C balance; thus, other factors need to be considered to reduce the uncertainty and refine the estimated C balance. However, stream C export is significant, especially for almost neutral sites where fluvial loss may determine the direction of the site C balance. The fate of C downstream then dictates the overall climate impact of fluvial export.

  15. Depositional architecture and developing settings of largescale incised valley and submarine gravity flow systems in the Yinggehai and Qiongdongnan basins, South China Sea

    Institute of Scientific and Technical Information of China (English)


    In the Ying-Qiong basins in the South China Sea developed a setof giant inner shelf slope and submarine gravity flow deposits in the Ying-Huang formations since the Late Miocene. These deposits can be classified into 9 sequences in which slope slump-debris flow, slope fan and particularly, the large-scale axial basin-floor incised valley fills have been recognized. They were distributed in a distinctive pattern attributed to tectonic control. The development of shelf slopes and abyssal plains in the basins was related to the last episode of rapid subsidence and a large amount of sediment inputs. Large-scale basin-floor incised valleys, formed during the late Miocene and Pliocene, indicate several major sea level falls that occurred in the South China Sea.

  16. Comparison of Modifications in Flap Anastomosis Patterns and Skin Incision Types for External Dacryocystorhinostomy: Anterior-Only Flap Anastomosis with W Skin Incision versus Anterior and Posterior Flap Anastomosis with Linear Skin Incision

    Directory of Open Access Journals (Sweden)

    Burcu Dirim


    Full Text Available Purpose. To compare the outcomes of external dacryocystorhinostomy (E-DCR by using two different flap anastomosis patterns and skin incision types. Methods. This study included 79 patients (88 eyes with lacrimal drainage system disorders who underwent E-DCR surgery. Fifty eyes of 44 patients (group A underwent E-DCR by suturing anterior and posterior flaps (H-flap of the lacrimal sac with curvilinear skin incision whereas in 38 eyes of 35 patients (group B DCR was performed by suturing only anterior flaps (U-flap with W skin incision. Results. The success rate was evaluated according to lacrimal patency and scar assessment scores. Patency was achieved in 78 patients (88.6%. In terms of groups, patency was 44 eyes (88.0% in group A and 34 eyes (89.5% in group B. There was no statistically significant difference in the success rates of lacrimal patency between the two groups. Further, there was no statistically significant difference concerning cutaneous scar scores. Conclusion. Our study suggests that anastomoses of only anterior flaps or both anterior and posterior flaps have similar success rates; suturing only anterior flaps is easier to perform and shortens the operative time. In addition, W skin incision is a reasonable alternative to curvilinear incision for reducing scar formation.

  17. Rapid Climate Change and Implications for Habitability on Mars (United States)

    Irwin, R. P.


    Ongoing work on Martian geomorphology suggests at least three phases of landscape modification: 1) ubiquitous crater degradation and development of intercrater geomorphic surfaces during at least the Middle and Late Noachian Epochs, 2) incision of valley networks around the Noachian/Hesperian transition, and 3) one or more intervals of lesser fluvial erosion in the Late Hesperian or Early Amazonian Epochs. Crater degradation was prolonged, but we do not know whether it was continuous or intermittent over long geologic timescales. It is also unknown whether the Hesperian decline in weathering and crater degradation was abrupt or gradual. Fluvial networks on dated surfaces suggest at least two periods of activity separated by significant time spans. For example, fluvial erosion occurred both before and well after the Gale crater and Holden crater impacts on opposite sides of Mars, and both before and after the development of the crustal dichotomy boundary scarp. Published estimates of discharge, runoff production, denudation, and drainage density are collectively consistent with geologically brief intervals of fluvial erosion. These results suggest that habitable surface environments may have been similarly short-lived, and that adaptation to subsurface environments would have been key to survival of microbial life. Studies of the Martian paleoclimate have tried to reconcile a faint young Sun with compelling evidence for past flowing and ponded water. Attempts to model a global mean temperature above 0°C have been mostly unsuccessful, suggesting either that input parameters are in error or that a different critical condition for fluvial erosion applied. Even assuming a thicker Noachian to Hesperian atmosphere, which would be necessary to support surface water, Mars would maintain cold traps at the poles under most axial obliquity conditions. An active water cycle would depend both on a thicker atmosphere and on liberating ice from the poles, perhaps temporarily

  18. Aggradation of gravels in tidally influenced fluvial systems: Upper Albian (Lower Cretaceous) on the cratonic margin of the North American Western Interior foreland basin (United States)

    Brenner, Richard L.; Ludvigson, Greg A.; Witzke, B.L.; Phillips, P.L.; White, T.S.; Ufnar, David F.; Gonzalez, Luis A.; Joeckel, R.M.; Goettemoeller, A.; Shirk, B.R.


    Alluvial conglomerates were widely distributed around the margin of the Early Cretaceous North American Cretaceous Western Interior Seaway (KWIS). Conglomerates, sandstones, and lesser amounts of mudstones of the upper Albian Nishnabotna Member of the Dakota Formation were deposited as fill-in valleys that were incised up to 80 m into upper Paleozoic strata. These paleovalleys extended southwestward across present-day northwestern Iowa into eastern Nebraska. Conglomerate samples from four localities in western Iowa and eastern Nebraska consist mostly of polycrystalline quartz with lesser amounts of microcrystalline (mostly chert), and monocrystalline quartz. Previous studies discovered that some chert pebbles contain Ordovician-Pennsylvanian invertebrate fossils. The chert clasts analyzed in this study were consistent with these findings. In addition, we found that non-chert clasts consist of metaquartzite, strained monocrystalline quartz and 'vein' quartz from probable Proterozic sources, indicating that parts of the fluvial system's sediment load must have travelled distances of 400-1200 km. The relative tectonic stability of this subcontinent dictated that stream gradients were relatively low with estimates ranging from 0.3 to 0.6 m/km. Considering the complex sedimentologic relationships that must have been involved, the ability of low-gradient easterly-sourced rivers to entrain gravel clasts was primarily a function of paleodischarge rather than a function of steep gradients. Oxygen isotopic evidence from Albian sphaerosiderite-bearing paleosols in the Dakota Formation and correlative units from Kansas to Alaska suggest that mid-latitude continental rainfall in the Albian was perhaps twice that of the modern climate system. Hydrologic fluxes may have been related to wet-dry climatic cycles on decade or longer scales that could account for the required water supply flux. Regardless of temporal scale, gravels were transported during 'high-energy' pulses, under

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

    Directory of Open Access Journals (Sweden)

    Heritage George


    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

  20. Climate and the erosional efficiency of fluvial systems (United States)

    Rossi, M. W.; Whipple, K. X.; Dibiase, R. A.; Heimsath, A. M.


    stochastic distribution of discharge events and thresholds of erosion. Stream gauges with long instrumental records provide the best observations to calibrate these models. However, not all parts of the Earth are sufficiently gauged for this approach. Instead, other atmospheric data products, like the North American Regional Analysis (NARR), can be used to provide more uniform spatial and temporal coverage and generate outputs comparable to fluvial discharge. Specifically, we evaluate the utility of NARR for assessing discharge variability in: the semi-arid SGM; the arid SSPM; the very wet SNdD. Since hydrological and meteorological data are more widely available for SGM, we use that site to calibrate our NARR interpretations for the other locations. The results of this analysis are used to refine stream erosion model predictions of erosional efficiency for all three sites that are then compared to field observations.

  1. Aeolian and fluvial processes in dryland regions: the need for integrated studies (United States)

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


    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.

  2. Single transverse extended incision for radical neck dissection. (United States)

    Chagas, José Francisco Sales; Pascoal, Maria Beatriz Nogueira; Aquino, José Luís Braga; Brandi, Luís Antônio; Previtale, Evandro Von Zuben; Trillo, Ana Sofia Pontes; Curioni, Otávio Alberto; Rapoport, Abrão; Dedivitis, Rogério Aparecido


    to assess the efficacy of the single transverse extended cervical incision in radical neck dissection. we conducted a prospective study, from January 2008 to January 2009, with 18 patients undergoing surgical treatment of malignant tumors of the upper aero-digestive tract. The primary lesion was located in the oral cavity in eight cases, in the oropharynx in three, in the hypopharynx in three, in the larynx in two, in the maxillary sinus, and in one case, the primary injury was hidden. There were 29 neck dissections, eight bilateral and 10 unilateral (26 radical and three selective). Staging revealed nine patients with T4 tumor, one T3, six T2, one T1 and one Tx. Five patients were N0, nine N2b, one N2c and three N3. The average number of dissected lymph nodes was 34.25. We performed the neck dissection through a single incision located in the middle neck, coincident with the skinfold, with a length of about 2 to 3 cm behind the anterior edge of the trapezius muscle and 3 to 4 cm from the midline for the unilateral neck dissections. as complications, there were myocutaneous flap necrosis in one patient with prior radiation therapy, one lymphatic fistula, one dehiscence of the tracheostomy, one cervical abscess, one salivary fistula and one suture dehiscence. the single extended incision provides adequate exposure of the neck structures, without compromising surgical time, even in bilateral dissections. It does not compromise the resection of all cervical lymph nodes; it has excellent aesthetic and functional results and is easily associated with other approaches to resection of the primary tumor. verificar a eficácia da incisão cervical única, transversa e estendida, para o esvaziamento cervical radical. estudo prospectivo, de janeiro de 2008 a janeiro de 2009, de 18 pacientes submetidos a tratamento cirúrgico de tumores malignos da via aero-digestiva superior. A lesão primária se situava na cavidade oral em oito casos, na orofaringe em três, no seio

  3. Extensive adipose tissue necrosis following pfannenstiel incision for endometrial cancer. (United States)

    Lavoie, Maryse Céline; Plante, Marie; Lemieux, Marie-Carine; Roberge, Céline; Renaud, Marie-Claude; Grégoire, Jean; Roy, Michel; Sebastianelli, Alexandra


    Contexte : Les hématomes sont des complications postopératoires qui peuvent en venir à se manifester à la suite du recours à des incisions de Pfannenstiel. Habituellement, ils se résorbent de façon spontanée ou font l’objet d’un drainage (en fonction de leur ampleur). Des facteurs de risque importants (comme l’obésité et le diabète) pourraient mener à des complications surajoutées et aggraver davantage l’issue. Cas : Dix jours après avoir subi une hystérectomie abdominale totale par incision de Pfannenstiel en raison d’un cancer de l’endomètre, une femme de 73 ans a présenté un gros hématome sous-cutané. L’hématome en question a évolué et a mené à une nécrose étendue du tissu adipeux sous-cutané. La mise en œuvre d’un débridement de grande envergure s’est avérée nécessaire et la plaie a été traitée par pression négative au moyen de gaze afin de permettre une cicatrisation par deuxième intention. Une guérison satisfaisante a été constatée après 82 jours de traitement, sans greffe cutanée. Conclusion : Ce cas souligne l’utilité du traitement de plaie par pression négative au moyen de gaze, ainsi que la nécessité d’avoir recours à une approche multidisciplinaire au moment d’assurer la prise en charge de complications de plaie d’une telle complexité.

  4. Development of a New Type of Incisal Table for Prosthetic Articulators

    Directory of Open Access Journals (Sweden)

    Alessandro Tasora


    Full Text Available This study illustrates the effectiveness of an advanced incisal table surface, featuring adjustable curvature, in the sake of more accurate articulator kinematics in anterior teeth reconstruction. Prosthetic articulators, used by dental technicians in reconstructive dentistry, are adjustable instruments that simulate the motion of mastication between dental casts: usually, the forward motion (protrusion of the mandible is guided by sliding a pin over a flat table in order to recreate those movements when incisal teeth are missing. However, such protrusion is an approximation of the exact motion, since flat incisal tables have a limited set of adjustments. Customized software has been developed in order to simulate the kinematics of articulators in three-dimensional space: animations and measures of the envelope of teeth profiles show the unfeasibility of reconstructing with good approximation the profile of incisive teeth, when a simple ‘flat’ incisal table is used. A new incisal table with an adjustable curvature has been proposed, simulated, and built, and computer simulations demonstrated the superior precision of the new design when compared to a conventional articulator which uses a flat incisal table.

  5. Percutaneous bone-anchored hearing implant surgery: dermatome versus linear incision technique. (United States)

    Strijbos, Ruben M; Bom, Steven J H; Zwerver, Stefan; Hol, Myrthe K S


    The objective of this historical cohort study is to identify if there are differences in soft tissue reactions and skin thickening between implantation of the percutaneous bone-anchored hearing implant (BAHI) using the dermatome or linear incision technique. All adult patients who received a BAHI between August 2005 and January 2013 were selected. One surgeon performed all procedures and only the dermatome and linear incision technique were used. A total of 132 patients/implants were included and significantly more patients with risk factors were seen in the linear incision cohort. A soft tissue reaction Holgers ≥1 was present in 18 patients (40.9 %) in the dermatome compared to 36 patients (40.9 %) in the linear incision group. A Holgers ≥2 was noticed in 9 (20.5 %) and 19 (21.6 %) patients, respectively. Skin thickening was described in 14 (31.8 %) and 11 patients (12.5 %) in, respectively, the dermatome and linear incision cohort, which was a significant difference (p = 0.001). Nevertheless, therapeutic interventions were effective. In conclusion, there was no significant difference in (adverse) soft tissue reactions; however, skin thickening was more present in the dermatome technique. In addition, significantly more patients with risk factors were allocated to the linear incision technique. Based on these results, the linear incision is advocated as preferred technique.

  6. [Dentascan computed tomography of the mandibular incisive canal. Its radiologic anatomy and the therapeutic implications]. (United States)

    Calgaro, A; Bison, L; Bellis, G B; Pozzi Mucelli, R


    To stress the importance of CT depiction of the mandibular incisive canal. This anatomical structure contains a major neurovascular bundle and is thus very important in the planning of mandibular implants in the canine-incisive area. January through December 1998, sixty patients unselected by age and gender were submitted to mandibular CT. Axial slices were acquired with 1-1.5 mm thickness and 1 mm table feed, and the images were then reformatted with a dedicated dental software. Both the conventional and the Helical techniques were used. The incisive canal appears on Dentascan transverse reconstructions as a round low-density area within mandibular trabecular bone, which is surrounded by a higher-density rim representing the canal walls. This anatomical structure originates from the mental foramen and continues mesially to the mental symphysis. The mandibular canal was visualized in 95% of cases bilaterally (57/60); the incisive canal was depicted on the left side in 41.6% of cases (25/60) and on the right side in 51.6% (31/60). The importance of careful assessment of the mandibular canal course before implantology is now widely recognized. The same holds true for the canine-incisive region in the jaw, to detect the incisive canal if present and prevent any complications from its accidental damage. CT with a dedicated software showed the incisive canal in a large number of patients, which calls for precise reporting of its presence, course, and relationships with teeth.

  7. Incision properties and thermal effects of CO2 lasers in soft tissue (United States)

    Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.; Liaw, Lih-Huei L.; Berns, Michael W.


    Thermal and histological events resulting from soft tissue incision using CO2 lasers at 9.3 (mu) or 10.6 (mu) , fitted with a hollow wave guide or an articulated arm delivery system respectively, were investigated. In 9 fresh pigs' mandibles, standardized incisions 3 cm in length were made in the oral mucosa. Incisions were performed in the cw mode at 1 W, 4 W, and 12 W. Thermal events were measured in adjacent soft tissues using thermocouples. Incisions were dissected out, fixed, embedded in paraffin wax, sectioned and stained with Serius Red. The Students' t-test for paired data was used to compare zones of necrosis, zones of collagen damage and thermal events. No significant temperature rise was measured during irradiation at any timepoints or power settings (p < 0.05). Results were very similar for the two lasers with significantly different results obtained only at the 12 W setting (p < 0.05). Vertical incision depths and horizontal incision widths did not differ significantly (p < 0.0001) at 12 W and 4 W. Horizontal and vertical zones of necrosis did not differ significantly (p < 0.0001) either between the two lasers at 12 W and 4 W. Thus the thermal and histological events occurring during soft tissue incision were similar using these two lasers, despite the difference in wavelength and delivery system.

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

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debasish


    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.

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

    Directory of Open Access Journals (Sweden)

    Arefah Dehghani Tafti


    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.

  10. Scar Assessment After Breast Augmentation Surgery with Axillary Incision versus Inframammary Fold Incision: Long-Term Follow-Up in Chinese Patients. (United States)

    Sun, Jingjing; Mu, Dali; Liu, Chunjun; Ji, Kai; Chen, Lin; Liu, Wenyue; Luan, Jie


    The inframammary fold (IMF) incision is widely used in Western countries for breast augmentation surgery, whereas the axillary incision is the dominant approach used in China, because many Chinese surgeons believe that the Asian population has a higher risk of developing hypertrophic scars. However, comparative data of scar assessment through different incisions in Chinese patients are scarce. The aims of the study were as follows: (1) to evaluate the outcomes of scar assessment using the Vancouver scar scale (VSS), combined with patient satisfaction scoring, in the scar assessment after breast augmentation surgery; (2) to compare the long-term cosmetic effects of surgical scars between axillary and IMF incisions. Consecutive patients coming to our department for follow-up care at least 1 year after primary breast augmentation surgeries with axillary and IMF incisions between January 1, 2014 and December 31, 2014 were included in the research. Internal consistency, inter-rater reliability, and convergent validity were examined for the VSS and patient satisfaction scoring. The baseline characteristics and scar scores were tested using the Mann-Whitney U-test and Student's t test between the two groups. Sixty-one patients underwent implantation surgeries through the axillary incisions, and 17 patients through the IMF incisions. There were no significant differences in age, follow-up time, body mass index, implant volume, or implant projection between groups. Reliability and validity of the VSS and patient satisfaction scoring were satisfactory. The scores of pigmentation were higher in the IMF group than those in the axilla group with statistical significance (P IMF group (P IMF can achieve comparable cosmetic effects and patient satisfaction in Chinese women. Chinese patients with proper indications can receive breast augmentation surgery through the IMF incision, with fewer risks and less trauma, and get satisfactory scar appearance as through the axillary

  11. A Middle-Upper Miocene fluvial-lacustrine rift sequence in the Song Ba Rift, Vietnam

    DEFF Research Database (Denmark)

    Lars H., Nielsen; Henrik I., Petersen; Nguyen D., Dau


    subsidence rate and possibly a higher influx of water from the axial river systems the general water level in the graben rose and deep lakes formed. High organic preservation in the lakes prompted the formation of two excellent oil-prone lacustrine source-rock units. In the late phase of the graben...... fluvial activity. It is likely that the resulting interbedding of fluvial sandstones and lacustrine sediments reflects variations in precipitation. In periods of little precipitation the lakes diminished and lake bottoms became exposed. After heavy precipitation, transverse river systems transported sands...... as carrier beds, whereas the braided fluvial sandstones and conglomerates along the graben margins may form reservoirs. The Krong Pa graben thus contains oil-prone lacustrine source rocks, effective conduits for generated hydrocarbons and reservoir sandstones side-sealed by the graben faults toward...

  12. Peat soils as a source of lead contamination to upland fluvial systems. (United States)

    Rothwell, James J; Evans, Martin G; Daniels, Stephen M; Allott, Timothy E H


    Upland peat soils are generally regarded as effective sinks of atmospherically deposited lead. However, the physical process of erosion has the potential to transform peat soils from sinks to sources of lead contamination. Lead input and fluvial lead outputs (dissolved+particulate) were estimated for a contaminated and severely eroding peatland catchment in the southern Pennines, UK. Lead input to the catchment is 30.0+/-6.0gha(-1)a(-1) and the output from the catchment is 317+/-22.4gha(-1)a(-1). Suspended particulate matter accounts for 85% of lead export. Contaminated peat soils of the catchment are a significant source of lead to the fluvial system. This study has demonstrated strong coupling between the physical process of erosion and the mobilization of lead into the fluvial system. The process of peat erosion should therefore be considered when estimating lead outputs from peatland catchments, especially in the context of climate change.

  13. Pollutant fates in fluvial systems: on need of individual approach to each case study (United States)

    Matys Grygar, Tomas; Elznicova, Jitka; Novakova, Tereza


    To outline the pollutant fates in fluvial systems it is necessary to combine two main kinds of knowledge: sedimentation and erosion patterns of each individual river with spatio-temporal resolution higher than in most fluvial geomorphology/sedimentology studies and timing and way how the pollutants have entered the fluvial system. Most of these aspects are commonly neglected in environmental geochemistry, a domain to which pollution studies apparently belong. In fact, only when these two main components are established (at least in a qualitative manner), we can start reading (interpretation) of the fluvial sedimentary archives, e.g., decipher the way how the primary pollution signal has been distorted during passing through the fluvial system. We conducted empirical studies on Czech rivers impacted by pollution (by risk elements). We learnt how individual (site-specific) are the main processes responsible for the primary pollution input, spread through each fluvial system and inevitable secondary pollution ("lagged pollution improvement signal"). We will discuss main features of the story on pollutant fates in three different fluvial systems, which have not been impacted by "hard" river engineering and still undergo natural fluvial processes: 1. the Ohre (the Eger) impacted by production of Hg and its compounds, historical mining of Pb and more recent U ore processing, 2. the Ploucnice impacted by U mining, and 3. the Litavka, impacted by Pb-Zn(-Sb) mining and smelting. The Ohre is specific by most pollution having been temporarily deposited in an active channel, only minor reworking of older fluvial deposits diluting pollution during downstream transport, and pollution archives existing practically only in the form of lateral accretion deposits. The deposits of archive value are rare and can be revealed by detailed study of historical maps and well-planned field analysis, best using portable analytical instruments (XRF). The Ploucnice is specific by only transient


    Institute of Scientific and Technical Information of China (English)

    S. L. HUANG; Z. H. WAN; P. SMITH


    A detailed discussion of existing three kinds of mathematical models of heavy metal pollutant transport-transformation in fluvial rivers is presented, with an emphasis on the mathematical model of heavy metal pollutant transport-transformation dynamics. The imperfection of two kinds of mathematical models, that is, mathematical model of chemical thermodynamic equilibrium and that of chemical reaction kinetics, and the shortcoming of existing mathematical models of heavy metal pollutant transport-transformation dynamics are pointed out. Furthermore, the structure of mathematical model of heavy metal pollutant transport-transformation dynamics in fluvial rivers is suggested. Equations in the mathematical model of heavy metal pollutant transport-transformation dynamics in fluvial rivers will be discussed in the following paper.


    Directory of Open Access Journals (Sweden)



    Full Text Available The role of the hydrological factor in habitat dynamics within the fluvial corridor of Danube. This paper had explored the connections between river hydrology with its changes and habitat dynamics. The fluvial corridor integrates spatially the channel and parts of its floodplain affected by periodical flooding and could be considered as an ecological corridor because of the size of the hydrosystem. The river and its ecosystems depend on geomorphogenetic and biological function and, thus creating a inter-dependence transposed into a concept, namely the fluvial hydrosystem, proposed firstly by Roux 1982, Amoros 1987. The hydrosystem is an ecological complex system constituted of biotopes and specific biocenoses of stream waters, stagnant water bodies, semi-aquatic, terrestrial ecosystems localized in the space of floodplain modeled directly and indirectly by river’s active force.

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


    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.

  17. [Intraocular pressure decrease after manual small incision cataract surgery]. (United States)

    Nganga Ngabou, C G F; Makita, C; Ndalla, S S; Nkokolo, F; Madzou, M


    We decided to evaluate the decrease in intraocular pressure six months after cataract surgery. We evaluated patients' IOP using an applanation tonometer. The patients then underwent cataract surgery. Six months after cataract surgery, we reevaluated the IOP by the same method, and we determined the post-operative change. Among the 147 operated eyes, 123 eyes or 83.67% exhibited a decrease in IOP. The mean preoperative IOP for the operative eye was 15.61±4.5mmHg; the mean post-operative IOP was 12.57±3.5mmHg; the mean IOP decrease after surgery was 3.16±4mmHg, for a mean decrease of 20%. This decrease is statistically significant, Pdecrease in IOP varies proportionally to the initial IOP. In glaucomatous patients, the mean preoperative IOP was 23.16±5.68mmHg and mean post-operative IOP was 14.5±2.7mmHg, a decrease of 37.39%. The decrease in IOP after cataract surgery was generally moderate. However, this IOP decreased proportionally to the initial IOP, thus giving significant decreases for higher IOPs. This decrease in IOP, well known after phacoemulsification, was also obtained after Manual Small Incision Cataract Surgery, a surgical technique which is increasingly employed in developing countries. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. Reproductive Outcome of Transcervical Uterine Incision in Unicornuate Uterus (United States)

    Xia, En-Lan; Li, Tin-Chiu; Choi, Sze-Ngar Sylvia; Zhou, Qiao-Yun


    Background: The pregnancy outcome of the unicornuate uterus is associated with an increased risk of miscarriage, cervical incompetence, and a number of obstetric complications. However, at present, there is no accepted treatment method for women with unicornuate uterus, other than expectant measures. The aim of this study was to evaluate the reproductive outcome of transcervical uterine incision (TCUI) in patients with unicornuate uterus. Methods: Thirty-three patients with unicornuate uterus presented to our tertiary center for infertility or miscarriage. All 33 patients underwent TCUI and were followed up for 10–52 months. The pregnancy outcomes (first-trimester miscarriage, second-trimester miscarriage, preterm, term, intrauterine death, ongoing pregnancy, and live birth) before and after TCUI were compared by t-test. Results: Among 31 patients who attempted to conceive after TCUI, twenty conceived including one termination of pregnancy, one second-trimester miscarriage, one ectopic pregnancy, five preterm deliveries, 11 term delivery, and one ongoing pregnancy. There were 16 live births in total. There was significant reduction in the first-trimester miscarriage rate (t = 4.890; P pregnancy outcome in women with unicornuate uterus presenting with infertility or miscarriage. PMID:28139506

  19. Computer guidance system for single-incision bimanual robotic surgery. (United States)

    Carbone, Marina; Turini, Giuseppe; Petroni, Gianluigi; Niccolini, Marta; Menciassi, Arianna; Ferrari, Mauro; Mosca, Franco; Ferrari, Vincenzo


    The evolution of surgical robotics is following the progress of developments in Minimally Invasive Surgery (MIS), which is moving towards Single-Incision Laparoscopic Surgery (SILS) procedures. The complexity of these techniques has favored the introduction of robotic surgical systems. New bimanual robots, which are completely inserted into the patient's body, have been proposed in order to enhance the surgical gesture in SILS procedures. However, the limited laparoscopic view and the focus on the end-effectors, together with the use of complex robotic devices inside the patient's abdomen, may lead to unexpected collisions, e.g., between the surrounding anatomical organs not involved in the intervention and the surgical robot. This paper describes a computer guidance system, based on patient-specific data, designed to provide intraoperative navigation and assistance in SILS robotic interventions. The navigator has been tested in simulations of some of the surgical tasks involved in a cholecystectomy, using a synthetic anthropomorphic mannequin. The results demonstrate the usability and efficacy of the navigation system, underlining the importance of avoiding unwanted collisions between the robot arms and critical organs. The proposed computer guidance software is able to integrate any bimanual surgical robot design.

  20. Corneal relaxing incision combined with phacoemulsification and IOL implantation

    Institute of Scientific and Technical Information of China (English)

    沈晔; 童剑萍; 李毓敏


    Objective: To analyze the effectiveness and safety of corneal relaxing incisions (CRI) in correcting keratometric astigmatism during cataract surgery. Methods: A prospective study of two groups: control group and treatment group. A treatment group included 25 eyes of 25 patients who had combined clear corneal phacoemulsification, IOL implantation and CRI. A control group included 25 eyes of 25 patients who had clear corneal phacoemulsification and IOL implantation.Postoperative keratometric astigmatism was measured at 1 week, 1 month, 3 months and 6 months. Results: CRI signifi-cantly decreased keratometric astigmatism in patients with preexisting astigmatism compared with astigmatic changes in the control group. In eyes with CRI, the mean keratometric astigmatism was 0.29±0.17 D(range 0 to 0.5 D) at 1 week, 0.41±0.21 D (range 0 to 0.82 D) at 1 month, respectively reduced by 2.42 D and 2.30 D at 1 week and 1 month postoperatively (P=0.000, P=0.000), and postoperative astigmatism was stable until 6 months follow-up. The keratometric astigmatism of all patients decreased to less than 1.00 D postoperatively. Conclusions: CRI is a practical, simple, safe and effective method to reduce preexisting astigmatism during cataract surgery. A modified nomogram is proposed. The long-term effect of CRI should be investigated.

  1. Señor Santo Niño Devotees' Lived Experiences in a Fluvial Parade

    Directory of Open Access Journals (Sweden)

    Norly C. Ibones


    Full Text Available The study intended to divulge the Señor Santo Niño devotees’ lived experiences in a fluvial parade as a component of the celebration of Cebu City’s Sinulog Festival. This utilized a phenomenological studies design of the respondents’ narratives on their lived experiences in the Sinulog Fluvial Parade. A bracketing process was adapted to separate the researcher’s perspective from the respondents’ lived experiences. Fluvial Parade espoused a significant celebration in the lives of the many devotees of Señor Santo Niño. Emotional bliss and peace of mind are evident in their faces as they welcomed Señor Santo Niño in his coming through his short voyage. They come to witness this event as a means of taking part in the celebration, expressing their gratitude to all the blessings, good health and many opportunities they have received, self-commitment and strong devotion to the child Jesus Christ. Fluvial parade showcased the Cebuano faith and tradition i.e. uniquely animistic and ritualistic Filipino. Señor Santo Niño symbolized as the giver of strength and the source of support among the devotees. As a whole, fluvial parade epitomized love, peace and unity, which heaved the Cebuanos to unconditional faith, as loyal devotees of the Holy Child Jesus. It is recommended that organizers of the annual fluvial parade will retain the best features of the celebration and will continue to find better ways to improve or disseminate information for wider participation and preservation of this unique Cebuano Christian heritage.

  2. "FluvialCorridor": A new ArcGIS toolbox package for multiscale riverscape exploration (United States)

    Roux, Clément; Alber, Adrien; Bertrand, Mélanie; Vaudor, Lise; Piégay, Hervé


    Both for scientists and river basin managers, development of automated geographic information system (GIS) tools is essential today to characterize riverscapes and explore biogeomorphologic processes over large channel networks. Since the 1990s, GIS toolboxes and add-in programs have been used to characterize catchments. However, there is currently no equivalent to a planimetric and longitudinal characterization of fluvial corridor networks at multiple scales. This paper describes FluvialCorridor, a new GIS toolbox. This package allows the user: (i) to extract a large set of riverscape features such as the main components of fluvial corridors from DEM and vector layers (e.g. stream network or valley bottom), and (ii) to aggregate spatial features into homogeneous segments and metrics characterizing each of them. The methodological frameworks involved have been previously described by Alber and Piégay (2011), Leviandier et al. (2012) and Bertrand et al. (2013) and this contribution focuses on the GIS tools allowing the user to automatically operate them. A case study on the Drôme River (France) is provided to illustrate the potential of the package both for geomorphologic understanding and target management actions. FluvialCorridor has been developed for ArcGIS with the related native Python library named ArcPy and tested on ArcGIS 10.0 and 10.1. Obviously, each component of the package can be used separately; however, it also provides a complete workflow for fluvial corridor characterization, even as the toolbox is continually under development and revision. Case study database, FluvialCorridor package and guidelines are available online at

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


    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.

  4. Amazonian-aged fluvial system and associated ice-related features in Terra Cimmeria, Mars (United States)

    Adeli, Solmaz; Hauber, Ernst; Kleinhans, Maarten; Le Deit, Laetitia; Platz, Thomas; Fawdon, Peter; Jaumann, Ralf


    The Martian climate throughout the Amazonian is widely believed to have been cold and hyper-arid, very similar to the current conditions. However, ubiquitous evidence of aqueous and glacial activity has been recently reported, including channels that can be tens to hundreds of kilometres long, alluvial and fluvial deposits, ice-rich mantles, and glacial and periglacial landforms. Here we study a ∼340 km-long fluvial system located in the Terra Cimmeria region, in the southern mid-latitudes of Mars. The fluvial system is composed of an upstream catchment system with narrow glaciofluvial valleys and remnants of ice-rich deposits. We observe depositional features including fan-shaped deposits, and erosional features such as scour marks and streamlined islands. At the downstream section of this fluvial system is an outflow channel named Kārūn Valles, which displays a unique braided alluvial fan and terminates on the floor of the Ariadnes Colles basin. Our observations point to surface runoff of ice/snow melt as the water source for this fluvial activity. According to our crater size-frequency distribution analysis the entire fluvial system formed during early to middle Amazonian, between ∼ 1.8-0.2+0.2 Ga to 510-40+40 Ma. Hydraulic modelling indicates that the Kārūn Valles and consequently the alluvial fan formation took place in geologically short-term event(s). We conclude that liquid water was present in Terra Cimmeria during the early to middle Amazonian, and that Mars during that time may have undergone several episodic glacial-related events.

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

    Directory of Open Access Journals (Sweden)

    Thomas R


    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.

  6. Simulating the Fluvial Erosion of Fine-Grained River Banks (United States)

    Darby, S. E.; Sarkkula, J.; Koponen, J.; Kummu, M.


    River bank erosion is the product of a suite of specific processes that together contribute significantly to the sediment yielded from river catchments. Many studies have emphasised that hydraulic erosion of bank-toe materials may exert a dominant influence on the long term rate of river bank retreat. Fluvial bank erosion rates are normally quantified using an excess shear stress model of the form E = k(τb-τc)a, where E is the erosion rate per unit time and unit bank area, τb is the boundary shear stress applied by the flow, k and τc are erodibility parameters (erodibility coefficient, k, and critical shear stress, τc), and a is an empirically derived exponent (equated to unity in bank erosion studies). This model has the advantage of simplicity, but in practice difficulties in estimating the values of the erodibility and shear stress parameters seriously inhibit its accuracy. We are seeking to improve the parameterization of the excess shear stress model through the use of field measurements and analytical modelling, at field sites on the Mekong River in Laos. Specifically, τb is estimated using a new model [Kean and Smith, 2006, J. Geophys. Res., 111(4), F04009, doi:10.1029/2006JF000467] of flow over irregular bank topography. Data from our study sites indicate that the form roughness induced by natural topographic bank features (slumps, embayments, etc) is a major component of the spatially-averaged total shear stress, with the skin friction component (i.e, τb) typically an order of magnitude less than the total stress. This indicates that previous bank erosion investigations, that employ estimates of the total shear stress, may grossly misparameterize the true value of τb. To estimate τc, we have employed a Cohesive Strength Meter [CSM, Tolhurst et al., 1999, Estuarine, Coastal & Shelf Sci., 49, 281-294], a jet-testing device that is normally used in studies of the stability of cohesive sediments on inter-tidal flats, but which has not previously been

  7. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Rahul Bhargava


    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


    Directory of Open Access Journals (Sweden)

    Udaya Kumar


    Full Text Available The aim of study was to achieve complete cortical cleanup and avoid problems related with sideport during Small Incision Cataract Surgery (SICS so as to have a good visual out come with minimal recovery period, and a better quality of life. After nucleus delivery, cortical cleanup is an important step in any cataract surgical procedure. Cortex especially subincisional area (11 to 1 o’clock is difficult to manage intraoperatively. Bimanual irrigation aspiration through two side ports, aspiration by J cannula, iris massage manoeuver, ice cream scoop manoeuver are various techniques of cortical matter aspiration. We acquired the technique of aspiration of subincisional cortex without using side port in all cases by paying attention on type of cataract, status of pupil, use of Adrenalin mixed BSS intraoperatively, Tunnel construction, Capsulorhexis size and capsular rim size at 12 o’clock. MATERIAL AND METHODS In this retrospective study of 1 year from 2013 to 2014, 60 patients (60 eyes aged 40 years or older attending the General Ophthalmic Department were included in the study group with another group of 60 patients (60 eyes as controls. The study was on age related cataracts which are basically. 1 Cortical cataract 2 Nuclear cataract 3 Subcapsular cataract. Proper assessment of cortical cataract based on its maturity such as a Immature b Mature c Hyper mature and d Morgagnian cataract, nucleus for its opalescence and color, size of posterior subcapsular opacity and pupillary status (Dilating well or not with mydriatics were taken into consideration. Eyes with pseudoexfoliation having poor pupillary dilation were also included. Eyes with congenital anomalies, congenital cataract, gross corneal and retinal pathologies, and glaucoma were excluded. RESULTS Among 60 study eyes in the study group 35 presented with cortical, 20 with nuclear cataract and 5 with posterior subcapsular cataracts. In 58(96.6% cases, sideport was not required; 3(5% eyes


    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. Our interdisciplinary group has investigated 1) the interrelationships of geomorphology, hydrology, and vegetation; and 2) ...

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

    Directory of Open Access Journals (Sweden)

    Sugamata A


    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

  12. A Single-Incision Fasciotomy for Compartment Syndrome of the Lower Leg. (United States)

    Ebraheim, Nabil A; Siddiqui, Saaid; Raberding, Craig


    Lower leg fasciotomy may be performed with a single lateral incision with or without fibulectomy, or by a double incision technique, with most surgeons preferring the later. The aim of this article is to describe a variation of an existing single-incision technique that will allow for the release of all four compartments with 1 incision. Our approach uses a paratibial route to release the deep posterior compartment (DPC) rather than a transfibular or parafibular route that has already been discussed in the literature. We approach the DPC from the anterior compartment, whereas the parafibular approach uses the posterior aspect of the fibula to reach the DPC. This affords a faster fasciotomy with a smaller flap, avoids potential damage to neurovascular bundle and among other advantages, makes its especially pragmatic for bedside fasciotomy, without the risk of injury to the peroneal nerves, which is common with dissection at the posterior aspect of the fibula.

  13. Clinical evaluation of a modified marginal sulcular incision technique in endodontic surgery. (United States)

    Kreisler, Matthias; Gockel, Ricarda; Schmidt, Irina; Kühl, Sebastian; d'Hoedt, Bernd


    The authors evaluated periodontal parameters following apical surgery using a new marginal sulcular incision. In 65 cases, surgical access was achieved by means of a sulcular incision technique without the involvement of the adjacent periodontia and the interproximal papillae and in 33 cases by means of a submarginal trapezoidal technique. Periodontal parameters (probing pocket depth, gingival recession, clinical attachment loss, and tooth mobility [periotest]) were recorded at baseline and after 6 months. Scar formation and the loss of papilla height were evaluated photographically. No significant changes in the attachment level and no loss of papilla height were found in either group. A slight gingival recession (0.2 +/- 0.4 mm) corresponding to the decrease in pocket depths occurred on the buccal aspect with the sulcular incision. Tooth mobility was significantly increased in both groups immediately and 6 months after surgery. Scar formation was more unfavorable with the submarginal incision.

  14. Cochlear implantation with Pulsar Med El: a novel small incision technique. (United States)

    Cuda, D


    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.

  15. Laparoscopic vs. small incision cholecystectomy : Implications for pulmonary function and pain. A randomized clinical trial

    NARCIS (Netherlands)

    Keus, F.; Ali, U. Ahmed; Noordergraaf, G. J.; Roukema, J. A.; Gooszen, H. G.; Van Laarhoven, C. J. H. M.


    Background: Upper abdominal surgery, including laparoscopic cholecystectomy (LC), is associated with post-operative pulmonary dysfunction. LC has, by consensus, become the treatment of choice for symptomatic cholecystolithiasis. The small-incision cholecystectomy (SIC), a procedure which does not re

  16. Single-incision laparoscopic-assisted ileal resection for adult intussusception

    Directory of Open Access Journals (Sweden)

    Hong Yu


    Full Text Available Adult intussuception is rare and laparotomy is required in most of the cases due to the potential pathologic underlying reasons. Although it is technically challenging, single-incision laparoscopic surgery can work as an alternative to laparotomy. Here we report the case of a 45-year-old man with intermittent right lower quadrant abdominal pain for 1 month. Abdominal enhanced computed tomography (CT scan was performed and ileo-ileal intussusception was found, with lipoma as a likely leading point. Ileal resection was performed using the single-incision laparoscopic-assisted technique. Multiple trocars in the umbilical incision technique and conventional instruments were used. After identification of the ileo-ileal intussusception, the involved small bowel was extracted from the umbilical incision, and resection and anastomosis were performed extracoporeally. The operation time was 65 min and the post-operative hospital stay was 2 days. The patient recovered uneventfully, with better cosmetic results.


    Institute of Scientific and Technical Information of China (English)

    刘宝国; 赵振生; 李明强; 陈荣鋭; 王建军; 张乃嵩


    Objective: To investigate for the feasibility and advantages performed by the unilateral big hockey stick incision (BHSI) in head and neck carcinoma. Methods: Neck dissection by using the unilateral big hockey stick incision (BHSI) was performed on 93 patients with head and neck carcinoma. Results: The big hockey stick incision has a cosmetic scar and not scar contraction and is barely visible and easily covered in hair and clothing; sufficient exposure of the operation field; a small area of marginal necrosis was occasionally seen at the apex of the skin flap due to having preoperative radiotherapy. Conclusion: The unilateral big hockey stick incision has adequate surgical access, good healing of skin flaps, and a good cosmetic result.

  18. Laparoscopic vs. small incision cholecystectomy : Implications for pulmonary function and pain. A randomized clinical trial

    NARCIS (Netherlands)

    Keus, F.; Ali, U. Ahmed; Noordergraaf, G. J.; Roukema, J. A.; Gooszen, H. G.; Van Laarhoven, C. J. H. M.

    Background: Upper abdominal surgery, including laparoscopic cholecystectomy (LC), is associated with post-operative pulmonary dysfunction. LC has, by consensus, become the treatment of choice for symptomatic cholecystolithiasis. The small-incision cholecystectomy (SIC), a procedure which does not

  19. Laparoscopic vs. small incision cholecystectomy: Implications for pulmonary function and pain. A randomized clinical trial.

    NARCIS (Netherlands)

    Keus, F.; Ali, U Ahmed; Noordergraaf, G.J.; Roukema, J.A.; Gooszen, H.G.; Laarhoven, C.J.H.M. van


    BACKGROUND: Upper abdominal surgery, including laparoscopic cholecystectomy (LC), is associated with post-operative pulmonary dysfunction. LC has, by consensus, become the treatment of choice for symptomatic cholecystolithiasis. The small-incision cholecystectomy (SIC), a procedure which does not

  20. Secondary rhinoplasty: reconstitution of the allar cartillages by a rhinoplasty with an external incision

    Directory of Open Access Journals (Sweden)

    Jorge Ishida

    Full Text Available Presentation of 62 cases of secondary nasal deformities treated by external incision. Several types of endonasal deformities were observed, properly classified and repaired. When excessive ressection was observed, local cartillage graft, septonasal or conchal types were employed.

  1. Effects of incision and irradiation on regional lymph node metastasis in carcinoma of the hamster tongue

    Energy Technology Data Exchange (ETDEWEB)

    Ohtake, K.; Shingaki, S.; Nakajima, T. (Nigata Univ. (Japan))


    The effects of incision and irradiation on regional lymph node metastasis in DMBA-induced squamous cell carcinomas of the hamster tongue are reported. Metastasis to the submandibular lymph nodes was confirmed histologically in 48.0% of the animals. The incidence of lymph node metastasis was significantly increased (65.9%) after repeated incisions of tongue carcinomas. Three gray whole-body irradiation also increased the rate of metastasis from 31.0% to 46.3%. Higher incidences of lymphatic vessel invasion after incision and concomitant lymph node metastasis in the lymphatic invasion-positive group indicated a stepwise relationship leading to an increase in lymph node metastasis after incision. Because of the high incidence of metastases and close resemblance to human carcinomas in the tumor cell deposition and establishment of metastatic foci, DMBA-induced tongue carcinoma with invasion may serve as an experimental model of human oral carcinomas.

  2. Single incision laparoscopic total abdominal colectomy with ileorectal anastomosis for synchronous colon cancer. (United States)

    Bardakcioglu, O; Ahmed, S


    Single incision laparoscopy is currently performed mostly for basic laparoscopic procedures involving single abdominal quadrants. The aim of this case report is to show that single incision laparoscopic techniques can be utilized for complex abdominal laparoscopic procedures with a large target organ and a working space involving all quadrants of the abdominal cavity. A single incision laparoscopic total abdominal colectomy with an ileorectal anastomosis and intraoperative CO(2) colonoscopy was performed for a patient with synchronous adenocarcinoma of the cecum and the sigmoid colon. The patient was discharged home on postoperative day 4 and had no immediate postoperative complications. Single incision laparoscopy is feasible for complex colorectal procedures. Some of the techniques used may be adapted further to achieve colonic resection via a natural orifice in the future.

  3. A Prospective, Randomized Study of Component Position in Two-Incision MIS Total Hip Arthroplasty: A Preliminary Study. (United States)

    Meneghini, R Michael; Smits, Shelly A


    Controversy exists regarding the ability to position the implants reliably in minimally invasive surgery (MIS) total hip arthroplasty (THA). This study compared the ability to accurately position components in the MIS two-incision versus single-incision approaches. Twenty-four patients were randomized to THA through one of three approaches, including the two-incision approach. Component position was measured with computed tomography. The mean deviation from the target acetabular anteversion was 14.8 degrees in the two-incision MIS group versus 6.4 degrees in the other two approaches (p = 0.006). A mean of 9.8 degrees deviation from the target femoral anteversion in the two-incision MIS approach group was observed compared with 5.3 degrees in the single-incision groups (p = 0.05). These results suggest there is a decreased ability to accurately position the components in the two-incision approach.

  4. Feasibility of single-incision laparoscopic cholecystectomyfor acute cholecystitis

    Institute of Scientific and Technical Information of China (English)


    AIM To assess the safety of single-incision laparoscopiccholecystectomy (SILC) for acute cholecystitis.METHODS: All patients who underwent SILC atSano Hospital (Kobe, Japan) between January 2010and December 2014 were included in this retrospectivestudy. Clinical data related to patient characteristics andsurgical outcomes were collected from medical records.The parameters for assessing the safety of the procedureincluded operative time, volume of blood loss,achievement of the critical view of safety, use of additionaltrocars, conversion to laparotomy, intraoperative and postoperativecomplications, and duration of postoperativehospital stay. Patient backgrounds were statisticallycompared between those with and without conversion tolaparotomy.RESULTS: A total of 100 patients underwent SILCfor acute cholecystitis during the period. Preoperativeendoscopic treatment was performed for suspectedcholedocholithiasis in 41 patients (41%). The mean timefrom onset of acute cholecystitis was 7.7 d. According tothe Updated Tokyo Guidelines (TG13) for the severity ofcholecystitis, 86 and 14 patients had grade Ⅰ and gradeⅡ acute cholecystitis, respectively. The mean operativetime was 87.4 min. The mean estimated blood loss was80.6 mL. The critical view of safety was obtained in 89 patients (89%). Conversion laparotomy was performedin 12 patients (12%). Postoperative complications ofClavien-Dindo grade Ⅲ or greater were observed in4 patients (4%). The mean duration of postoperativehospital stay was 5.7 d. Patients converted from SILC tolaparotomy tended to have higher days after onset.CONCLUSION: SILC is feasible for acute cholecystitis;in addition, early surgical intervention may reduce therisk of laparotomy conversion.

  5. Single-Incision Laparoscopic Repair of Spigelian Hernia (United States)

    Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne J.


    Introduction: Spigelian hernias represent only 1% to 2% of all abdominal wall hernias. The treatment, however, remains controversial but depends on institutional expertise. This case series reports the first experience with single-incision laparoscopic totally extraperitoneal (SILTEP) repair of Spigelian hernias with telescopic extraperitoneal dissection in combination with inguinal hernia repair. Methods: From February 2013 to April 2014, all patients referred with inguinal or Spigelian hernias, without histories of extraperitoneal intervention, underwent SILTEP repair with telescopic extraperitoneal dissection. A single-port device, 5.5 mm/52 cm/30° angled laparoscope, and conventional straight dissecting instruments were used for all cases. Extraperitoneal dissection was performed under direct vision with preservation of preperitoneal fascia overlying retroperitoneal nerves. Inguinal herniorrhaphy was performed with lightweight mesh that covered low-lying Spigelian defects. High-lying Spigelian defects were repaired with additional mesh. Results: There were 131 patients with 186 (92 direct) inguinal hernias and 7 patients with 8 Spigelian hernias (6 incidental, including 1 bilateral and 2 preoperatively diagnosed), with a mean age of 51.3 years and a mean body mass index of 25.1 kg/m2. An additional piece of mesh was used for 3 hernias. All Spigelian hernias were associated with direct inguinal hernias, and 8 combined inguinal and Spigelian hernias were successfully repaired with SILTEP repair with telescopic extraperitoneal dissection as day cases. There were no clinical recurrences during a mean follow-up period of 6 months (range, 1–15 months). Conclusions: Combined Spigelian and inguinal hernias can be successfully treated with SILTEP herniorrhaphy with telescopic extraperitoneal dissection. The high incidence of Spigelian hernias associated with direct inguinal hernias suggests a high index of suspicion for Spigelian hernias during laparoscopic inguinal

  6. Teaching Incision and Drainage: Perceived Educational Value of Abscess Models. (United States)

    Adams, Cynthia M; Nigrovic, Lise E; Hayes, Gavin; Weinstock, Peter H; Nagler, Joshua


    Incision and drainage (I&D) of skin abscesses is an important procedural skill for pediatric emergency medicine providers. Practical skills training using simulation provides an opportunity to learn and gain confidence with this invasive procedure. Our objective was to assess the perceived educational value of 2 versions of an abscess model as part of an educational workshop for teaching I&D. A combined didactic and practical skills workshop was developed for use at 2 national conferences. The didactic content was created through an iterative process. To facilitate hands-on training, 2 versions of an abscess model were created: 1 constructed from a negative mold and the other using a 3-dimensional printer. Participants were surveyed regarding prior experience with I&D, procedural confidence, and perceptions of the educational utility of the models. Seventy physicians and 75 nurse practitioners participated in the study. Procedural confidence improved after training using each version of the model, with the greatest improvements noted among novice learners. Ninety-four percent of physicians, and 99% of nurse practitioners rated the respective models as either "educational" or "very educational," and 97% and 100%, respectively, would recommend the abscess models to others. A combined didactic and practical skills educational workshop using novel abscess models was effective at improving learners' confidence. Our novel models provide an effective strategy for teaching procedural skills such as I&D and demonstrate a novel use of 3-dimensional printers in medical education. Further study is needed to determine if these educational gains translate into improvement in clinical performance or patient outcomes.

  7. Manual small incision cataract surgery in eyes with white cataracts

    Directory of Open Access Journals (Sweden)

    Venkatesh Rengaraj


    Full Text Available PURPOSE: To assess the safety and efficacy of Manual Small Incision Cataract Surgery (MSICS in cases of white cataract with the use of trypan blue as an adjunct for performing continuous curvilinear capsulorthexis (CCC. MATERIALS AND METHODS: Prospective observational study on 100 consecutive eyes of 100 patients with white cataract who had undergone MSICS with trypan blue assisted CCC. The nucleus was prolapsed into anterior chamber by using a sinskey hook and extracted out of the eye using irrigating vectis. Intraoperative and postoperative findings (according to OCTET classification as well as postoperative visual outcomes were used as main measures to report the safety and efficacy of the surgery. RESULTS: Of the 100 eyes, 16 had intumescent, 67 had mature and 17 had hypermature cataract. Intraoperatively CCC was incomplete in 4 eyes (4% and had to be converted to canopener capsulotomy. None of the eyes had posterior capsular rupture or zonular dialysis and no eyes were converted to conventional Extra Capsular Cataract Extraction (ECCE. Postoperatively, 6 eyes (6% developed corneal oedema with >10 Descemets folds and 7 eyes (7% had corneal oedema with < 10 Descemets folds. Mild iritis was seen in 6 eyes (6% and moderate iritis with fibrin membrane was seen in 3 eyes (3%. Iridodialysis was observed in 1 eye (1%. Of the 99 patients (99% categorised under good visual outcomes category, 94 patients (94% had a best-corrected visual acuity of 6/9 or better on the 40th post-operative day. CONCLUSION: In developing countries like India where phacoemulsification may not be affordable to a majority of those requiring cataract surgery, MSICS proves to be a safe and efficacious alternative for white cataracts especially with the adjunctive use of trypan blue dye.

  8. Basal lamella relaxing incision improves endoscopic middle meatal access. (United States)

    Getz, Anne E; Hwang, Peter H


    Lateralization of the middle turbinate is a commonly cited factor leading to failure of functional endoscopic sinus surgery (FESS). Inadequate medialization during FESS may require repeat intraoperative attempts, and may lead to destabilization and mucosal trauma. A novel technique is described that increases middle meatal area and provides more definitive medialization at the outset of FESS. Twenty-nine middle turbinate medializations were prospectively evaluated in 18 consecutive patients undergoing primary ESS. Three intraoperative images of the middle meatus were obtained in the native position, after Freer medialization, and after basal lamella relaxing incision (BLRI). Measurements of middle meatal area were then calculated in a blinded and randomized fashion. Distances measured from the middle turbinate to the lateral nasal wall for each position ranged from 0 to 8 mm (median = 3.00 mm) for the native position, 0.5 to 10 mm (median = 5.00 mm) for standard Freer medialization, and 3 to 21 mm (median = 10.00 mm) for BLRI. Friedman's analysis of variance (ANOVA) showed that there was significant difference between the 3 measurements, and the post hoc Wilcoxon signed ranks tests showed that BLRI distance (median = 10; 95% confidence interval [CI], 7-11.2) was significantly larger than both standard Freer (median = 5; 95% CI, 4-6.2) and native (median = 3; 95% CI, 2-3) and that standard Freer was significantly larger than native (all p values BLRI is a safe, controlled technique that provides significantly greater medialization of the middle turbinate compared to standard medialization techniques. BLRI significantly enhances the operative space within the middle meatus. © 2013 ARS-AAOA, LLC.

  9. Incision of alluvial channels in response to a continuous base level fall: Field characterization, modeling, and validation along the Dead Sea (United States)

    Ben Moshe, L.; Haviv, I.; Enzel, Y.; Zilberman, E.; Matmon, A.


    The dramatic lake level drop of the Dead Sea during the twentieth century (˜ 30 m) provides a field-scale experiment in transport-limited incision of gravel-bed channels in response to quasi-continuous base level fall at approximately constant rate. We apply a one-dimensional numerical incision model based on a linear diffusion equation to seven ephemeral channels draining into the Dead Sea. The model inputs include the measured twentieth century lake level curve, annual shoreline location (i.e., annual channel lengthening following the lake level drop), reconstructed longitudinal profiles of each of the channels based on mapped and surveyed terraces, and the current profiles of the active channels. The model parameters included the diffusion coefficient and the upstream-derived sediment flux. Both were first calibrated using a set of longitudinal profiles of known ages and then validated using additional sets of longitudinal profiles. The maximum at-station total incision observed at each of the studied channels was significantly less then the total lake level drop and varied in response to both drainage area and lake bathymetry. The model applied predicted degradation rates and the pattern of degradation with high accuracy. This suggests that sediment flux in the modeled channels is indeed linearly dependent on slope. Further support for this linear dependency is provided by a linear correlation between the diffusion coefficient and the mean annual rain volume over each basin (a proxy for discharge). The model presented could be a valuable tool for planning in rapid base level fall environments where incision may risk infrastructure.

  10. Channel Incision and Suspended Sediment Delivery at Caspar Creek, Mendocino County, California. (United States)

    Dewey, N. J.; Lisle, T. E.; Reid, L. M.


    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. Gullies resulting from both of these episodes of incision are sensitive to hydrologic fluctuations and feature active headcuts, deepening plungepools, and unstable banks, which continue to contribute sediment to the Caspar Creek channel network. Headcuts are numerous in each channel. In some cases headcuts define the upstream extent of an incised reach; in many cases headcuts migrate up previously incised reaches, increasing the depth of incision. Surveys indicate that bank retreat, plunge pool deepening, and headcut retreat all contributed sediment to the channels between 2000 and 2003. Since bank walls have considerably more surface area than headwalls per given length of channel, and headcuts have largely migrated into positions temporarily constrained by resistant lips, bankwall retreat appears to be a more significant chronic source of sediment than headwall retreat. Stream gage records show that some channels consistently deliver higher levels of suspended sediment than others. In comparing channels, ongoing levels of suspended sediment delivery correlate well with total amount of exposed channel bank (depth of incision integrated over length of channel) in the reaches upstream of stream gages. On an annual to decadal time-scale, rates of suspended sediment delivery per unit area of catchment correlate better with the amount of exposed bank area in reaches upstream of stream gages, than with the volume of sediment delivered by landslide events, with total catchment area, or with peak storm flow per unit area. The correlation between amount of exposed bank area and ongoing levels of suspended sediment delivery is

  11. Microsurgical open mini uniskin incision technique in the surgical treatment of carpal tunnel syndrome


    Keramettin Aydin; Cengiz Cokluk; Nilgun Cengiz; Ayhan Bilgici


    Background: Patients who undergo carpal tunnel surgery sometimes complain of the restriction of the grip and pinch function, palmar tenderness, cosmetic problems, and scar formation at the site of the incision. Aims: We used a modified mini uni-skin incision with appropriate hand position for microscopic view in the surgical treatment of carpal tunnel syndrome to prevent cosmetic problems related with scar formation after surgery. Settings and Design: In this study we used two different ...

  12. Acute Compartment Syndrome in the Forearm with Trans-Ulnar Single Incision. (United States)

    Suzuki, Taku; Inaba, Naoto; Sato, Kazuki


    We report a case of ulnar nerve palsy caused by diaphyseal fractures of the forearm and acute compartment syndrome. Trans-ulnar single incision with a fasciotomy of the volar and dorsal compartments was used to fix the ulna. Full recovery of the ulnar nerve was achieved six months after the surgery. In cases of acute compartment syndrome with ulnar fracture, a trans-ulnar incision with compartment release is effective for the fixation of the ulna.

  13. Prime Incision and Modified Moving Window: A Minimally Invasive Access for Breast Cancer Surgical Treatment


    E. Bromberg, Silvio; Giordano, Roberto


    BACKGROUND Conservative surgical treatment has been the treatment of choice for early breast cancer. It allows feasible oncological treatment with a satisfactory cosmetic approach and fast recovery. However, in some cases mastectomy is necessary. This study proposes a surgical approach with only one surgical access through the same incision, which is in line with precepts mentioned above. It is called the prime incision and modified moving window techniques. METHODS Thirty one patients with a...

  14. Spontaneous alignment of crowded inferior incisives after the extractionof temporary canines


    Orellana Manrique, Tomás Oriel; Departamento Académico de Estomatología Pediátrica. Facultad de Odontología UNMSM. Lima Perú.; Calderón Cortez, Iván; Estudiante de pre grado. Facultad de Odontología UNMSM. Lima Perú.; Orellana Manrique, Martín; Estudiante de Maestría. Facultad de Odontología UNMSM. Lima Perú.


    This investigation evaluated the behavior of permanent inferior incisives after the primary canine’s extractions. The study was carried out in the Pediatric Clinic of Dental Faculty of San Marcos University. The sample was conformed by 10 patients, male and female children, between 8 and 9 years of age, with good general health, having Class I malocclusion and severe crowding of the inferior incisives. It was taken Cephalometric and Panoramic radiographies, as well as models to make the ortho...

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


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


    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...

  16. Do height and weight affect the feasibility of single-incision laparoscopic cholecystectomy?


    Meillat, Hélène; Birnbaum, David Jérémie; FARA, Régis; Mancini, Julien; Berdah, Stéphane; BEGE, Thierry


    Laparoscopic cholecystectomy is the gold standard for gallbladder removal and the most common laparoscopic procedure worldwide. Single-incision laparoscopic surgery has recently emerged as a less invasive potential alternative to conventional three- or four-port laparoscopy. However, the feasibility of single-incision laparoscopic cholecystectomy (SILC) remains unclear, and there are no rigorous criteria in the literature. Identifying patients at risk of failure of this new technique is essen...

  17. Single laser incision for treatment of congenital bladder neck sclerosis: new technique. (United States)

    Mattioli, Stefano; Picinotti, Alessandro; Burgio, Andreina


    The primary bladder neck obstruction (PBNO) has been recognized in 41-45% of young men suffering from a chronic lower urinary tract symptom (LUTS). Few studies are published in the literature about the use of laser devices in the surgical treatment of PBNO and none about the use of Thulium laser. The aim of our study is to report the results of our follow-up in the endoscopic treatment of PBNO with Thulium laser. From January 2012 to January 2015, we treated 214 patients using Thulium laser for primary bladder neck sclerosis. All patients had symptoms suggestive of LUTS or prostatism: filling or irritative symptoms and voiding or obstructive symptoms. In 157 patients, the incision was performed unilaterally at 7 o'clock of the bladder neck. In 57 cases, bilateral incision was performed at 5 and 7 o' clock without vaporizing the tissue between the two incisions. We chose to make the incision bilaterally in cases wherein a single incision was not enough to solve the obstruction from the bladder neck and prevent a recurrence. Bladder irrigation was used overnight in all cases, and the catheter was removed after 24 hours. One hundred ninety-six patients enrolled completed 1-year follow-up: 157 patients underwent unilaterally incision and 39 bilateral incision. In 179 cases (91.3%), there was unchanged antegrade ejaculation, while reduced semen volume was reported by 14 men (7.1%) and retrograde ejaculation by only 3 (1.5%), but these patients underwent bilateral incision. The quality of orgasm and sexual satisfaction was not permanently changed by the operation. In patients with PBNO, it is possible to perform endoscopic treatment with Thulium laser that we think is an effective and safe procedure, not affecting sexual functioning and particularly retrograde ejaculation.

  18. Two-incision approach for video-assisted thoracoscopic sleeve lobectomy. (United States)

    Peña, Emilio; Blanco, Montserrat; Ovalle, Juan Pablo


    The video-assisted thoracoscopic approach for bronchoplasty procedures is not standardized. Although 3 to 4 incisions are usually made, with adequate surgical technique, the operation can be successfully carried out using only 2 incisions. We describe the technique of video-assisted thoracoscopic surgery for a right upper lobe sleeve lobectomy for a carcinoid tumor in the right upper bronchus, using only 2 ports.

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

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


    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.

  20. Monitoring the Dynamic of a Fluvial Channel after Lahar Disturbance: Huiloac Gorge (Popocatepetl Volcano, Mexico) (United States)

    Andres, N.; Palacios, D.; Zamorano, J. J.; Tanarro, L. M.; Renschler, C.; Sanjosé, J. J.; Atkinson, A.


    laharic deposition formations. These features are attributed to an unusually long rainy season with above average values in October, and to atypical precipitation in the normally dry month of January. Modifications in the surface area from February 2004-March 2006 reached 19.2%, a decrease from the previous two-year period (28.1%), which was caused by a slight increase in average precipitation in 2004 and a marked decrease in 2005. Values for erosion (620 m3) and deposition (621 m3) are similar for the period from September 2003 - March 2005, and the slopes receded slowly as new laharic deposits increased the level of the channel floor. The final two-year interval shows an increase in changes (31.1%) where the receding sides of the banks affected the ridges of the levees, and the floor of the channel, marked by areas of deposition and incision, became flatter and wider. The increased activity is associated with the prolonged effect of El Niño (ENSO), more rainfall during the 2006 rainy season, and below reference values for 2007 for the average wet and dry seasons. The volume of material removed and accreted was 1424 m3 and 277 m3, respectively. Changes occurring in the channel to recover equilibrium in the river system included the widening and infilling of the floor, but these alterations were largely conditioned by increased water supply that triggered secondary lahars. The short interval between deposition by the primary lahar and the exceptionally heavy precipitation at the end of the rainy season, contributed to increased erosion of the gorge. The time intervals that registered below average precipitation are characterized by less surface disturbances and greater infilling of the channel floor. The opposite is true for the rainy seasons with above average values when slope erosion caused uneven deposition on the channel floor, or during the dry months that registered the most significant changes in response to episodes of exceptional heavy rainfall. References

  1. Whether superficial abdominal reflex is affected by subcostal transverse abdominal incisions? A prospective, observational early experience

    Directory of Open Access Journals (Sweden)

    Jitin Bajaj


    Full Text Available Introduction: Superficial abdominal reflex (SAR is an important part of the neurologic assessment. It is normally present and may be present or absent in various physiological as well as pathological conditions. The presence of an abdominal incision creates a dilemma in the mind of the clinician for it affecting this reflex. As there is no literature on this, we decided to study the effect of abdominal incisions on SAR. Materials and Methods: It was a prospective, observational study. We evaluated the patients requiring transverse subcostal incision (range 3–12 cm both preoperatively and postoperatively, for their abdominal reflexes. Patients with preoperative normal and symmetrical abdominal reflexes were included in the study. Postoperatively, we compared the change of SAR with the preoperative status and analyzed the data. Results: A total of 94 patients underwent surgeries, out of which 54 patients came under inclusion criteria, comprising 36 males and 18 females. Subcostal transverse abdominal incisions were made for surgeries including both gastrointestinal and ventriculoperitoneal shunts. SAR was found unaffected by the incisions in all patients. Conclusions: Although the study was small, subcostal transverse abdominal incisions were not found to affect SAR.

  2. Evaluation of four suture materials for surgical incision closure in Siberian sturgeon (United States)

    Boone, S. Shaun; Hernandez, Sonia M.; Camus, Alvin C.; Peterson, Douglas C.; Jennings, Cecil A.; Shelton, James L.; Divers, Stephen J.


    The visual and microscopic tissue reactions to the absorbable monofilament Monocryl, absorbable monofilament triclosan-coated Monocryl-Plus, absorbable multifilament Vicryl, and nonabsorbable monofilament Prolene were evaluated for their use of surgical closure in Siberian Sturgeon Acipenser baerii. Postoperative assessments were conducted at 1, 2, 8, 12, and 26 and 55 weeks to visually evaluate the surgical incision for suture retention, incision healing, erythema, and swelling. Incisions were also assessed microscopically at 1, 2, and 8 weeks for necrosis, inflammation, hemorrhage, and fibroplasia. The results indicated that incisions closed with either Vicryl or Prolene suture materials were more likely to exhibit more erythema or incomplete healing compared with those closed with Monocryl or Monocryl-Plus. The surgical implantation of a transmitter in the coelomic cavity did not significantly affect the response variables among the four suture materials. Monocryl or Monocryl-Plus were equally effective and superior to other suture materials used for closing surgical incisions in Siberian Sturgeon or closely related species of sturgeon. Furthermore, Monocryl or Monocryl-Plus may decrease the risk of transmitter expulsion through the incision, as surgical wounds appear to heal faster and exhibit less erythema compared with those closed with Vicryl.

  3. Watershed-scale modeling of streamflow change in incised montane meadows (United States)

    Essaid, Hedeff I.; Hill, Barry R.


    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.

  4. Effect of lateral temporal corneal incision for intraocular pressure and tear film stability in cataract patients

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    Ying Wang


    Full Text Available AIM: To investigate therapeutic effect of lateral temporal corneal incision phacoemulsification combined with intraocular lens(IOLon cataract and its effect on intraocular pressure(IOPand tear film. METHODS: The clinical data of patients with cataract who received treatment in our hospital from March 2014 to December 2015 were retrospectively analyzed. According to the location of the incision, they were divided into temporal corneal incision group and upper corneal incision group. We observed the incidence of complications of the two groups, compared the intraocular pressure, visual acuity, refraction and tear film break-up time of the two groups before and after surgery. RESULTS: The operation time and postoperative pain score of the two groups had no significant difference(P>0.05. The IOP and visual acuity between the two groups before operation had no significant difference(P>0.05. At the intraocular pressure of the two groups was lower than that before operation, and the visual acuity was higher than before operation, and the changes of the anterior lateral incision group were more obvious(PPCONCLUSION: The temporal corneal incision phacoemulsification combined with intraocular lens implantation has a good therapeutic effect on cataract patients, can effectively improve the intraocular pressure and tear film stability, improve eye function, promote the recovery of the body after surgery.

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

    Directory of Open Access Journals (Sweden)

    Parvu Valentin


    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.

  6. Quality of linear incisions performed by dental students using Er:YAG laser in soft tissue (United States)

    Novelli, Moacyr Domingos; Vasques, Mayra Torres; Meneguzzo, Daiane Thaís; Aranha, Ana Cecília Corrêa; Corrêa, Luciana


    Introduction: New technologies in dental practice, such as laser, have enabled new strategies to be established in dental education. The aim of this study was to analyze the difficulties that dental students encountered with performing surgical incisions using Er:YAG laser (LE), and the morphology of these incisions. Material and Methods: Sixteen undergraduate dental students and ten dental professionals (DP) enrolled at The Master of Science Program in Laser Dentistry were asked to perform 15 incisions using an LE and 15 with a conventional scalpel. The incisions were compared, based on the shape factor (relation between area and perimeter), which was obtained by a digital image system and by a morphometry software. Data was submitted to statistical analysis of variance (p 0.05). Results: Considering the incisions performed by scalpel, DP showed statistically significant differences (p cutting speed, and absence of suction and water jet appliances. None of the groups performed adequate incisions using LE. Conclusion: Greater emphasis is required in relating laser therapy practice to the physical properties of laser, particularly for dental professionals that specialize in laser.

  7. [The treatment of otosclerosis using laser assisted stapedotomy with mini incision in external auditory meatus]. (United States)

    Hao, Xinping; Chen, Shubin; Yu, Zilong; Liang, Fenghe; Li, Yongxin


    To investigate the feasibility of the treatment of otosclerosis using laser stapedotomy with mini incision in the external auditory meatus. Thirteen patients(15 ears) with otosclerosis evidence on clinic history. They were all operated using the laser assisted stapedotomy by mini incision in external auditory meatus because of the wide straight canal. Laser resection the tendo musculistapedius and anterior and postrior arch, breaking the articulatioincudostapedia, removing the stapes superstructure, making a hole of 6mm diameter in the rear of stapes footplate by laser drilling, implanting the corresponding length Piston artificial ossicle. All the surgeries were successful and the operation time was about one hour. There was only one patient manifested vertigo and nausea after the operation. But the symptoms improved three days later after the expectant treatment. All the incisions were healed in the externals. There was significant difference between the preoperative and postoperative PTA. The air conduct improved in every frequent and the bone conduct improved in 1 kHz, 2 kHz and 4 kHz. Laser assisted stapedotomy by mini incision in the external auditory meatus in patients having wide straight canal with otosclerosis can shorten the operation time, minimize the tissue damage, fasten the healing of the incision and reduce the complications postoperatively. In addition, the mini incision is beauty and easy to nurse.

  8. "The Waters of Meridiani" - Further Support for a Fluvial Interpretation of the Ridged, Layered Units (United States)

    Wilkinson, Justin; Kreslavsky, Misha


    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.

  9. Mixed fluvial systems of Messak Sandstone, a deposit of Nubian lithofacies, southwestern Libya

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, J.C.


    The Messak Sandstone is a coarse to pebbly, tabular cross-bedded, Lower Cretaceous deposit of the widespread Nubian lithofacies. It was deposited at the northern edge of the Murzuq basin in southwestern Libya. Although the sedimentary record is predominantly one of braided fluvial systems, a common subfacies within the formation is interpreted to record the passage of straight-crested sand waves across laterally migrating point bars in sinuous rivers, similar to the pattern documented by Singh and Kumar on the modern Ganga and Yamuna Rivers. Because the sand waves were larger on the lower parts of the point bars, lateral migration created diagnostic thinning-upward, unidirectional cosets of tabular cross-beds as well as fining-upward, grain-size trends. Common, thick, interbedded claystones, deposited in associated paludal and lacustrine environments, and high variance in cross-bed dispersion patterns also suggest the local presence of sinuous fluvial systems within the overall braided regime. The Messak Sandstone contains some of the features that led Harms et al to propose an unconventional low-sinuosity fluvial environment for the Nubian lithofacies in Egypt, and the continuously high water levels of this model may explain channel-scale clay drapes and overturned cross-beds in the Messak. However, most of the Messak characteristics are incompatible with the low-sinuosity model, suggesting instead that the fluvial channels in the Murzuq basin alternated between braided and high-sinuosity patterns.

  10. Variables and potential models for the bleaching of luminescence signals in fluvial environments (United States)

    Gray, Harrison J.; Mahan, Shannon


    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.

  11. 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)


    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.

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

    Sheryl Coombs; Gary D. Grossman


    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...

  13. 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.; van der Schriek, T.; Reimann, T.; Wallinga, J.; Wijbrans, J.; Schoorl, J. M.


    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 flo

  14. 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.


    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 potentia

  15. 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.


    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 potentia

  16. Mount Kenya volcanic activity and the Late Cenozoic landscape reorganisation in the upper Tana fluvial system

    NARCIS (Netherlands)

    Veldkamp, A.; Schoorl, J.M.; Wijbrans, J.R.; Claessens, L.F.G.


    Volcanic–fluvial landscape interaction of the late Cenozoic Mt Kenya region in the upper Tana catchment has been reconstructed. The oldest newly dated phonolite flow is 5.78 Ma (40Ar/39Ar), placing the initiation of Mt Kenya volcanic activity within the Late Miocene, much earlier than reported befor

  17. Response of the Rhine-Meuse fluvial system to Saalian ice-sheet dynamics

    NARCIS (Netherlands)

    Busschers, F.S.; Balen, R.T. van; Cohen, K.M.; Kasse, C.; Weerts, H.J.T.; Wallinga, J.; Bunnik, F.P.M.


    A new reconstruction of the interaction between the Saalian Drente glaciation ice margin and the Rhine-Meuse fluvial system is presented based on a sedimentary analysis of continuous core material, archived data and a section in an ice-pushed ridge. Optically Stimulated Luminescence (OSL) was applie

  18. Fluvial rainbow trout contribute to the colonization of steelhead (Oncorhynchus mykiss) in a small stream (United States)

    Weigel, Dana E.; Connolly, Patrick J.; Powell, Madison S.


    Life history polymorphisms provide ecological and genetic diversity important to the long term persistence of species responding to stochastic environments. Oncorhynchus mykiss have complex and overlapping life history strategies that are also sympatric with hatchery populations. Passive integrated transponder (PIT) tags and parentage analysis were used to identify the life history, origin (hatchery or wild) and reproductive success of migratory rainbow/steelhead for two brood years after barriers were removed from a small stream. The fluvial rainbow trout provided a source of wild genotypes to the colonizing population boosting the number of successful spawners. Significantly more parr offspring were produced by anadromous parents than expected in brood year 2005, whereas significantly more parr offspring were produced by fluvial parents than expected in brood year 2006. Although hatchery steelhead were prevalent in the Methow Basin, they produced only 2 parr and no returning adults in Beaver Creek. On average, individual wild steelhead produced more parr offspring than the fluvial or hatchery groups. Yet, the offspring that returned as adult steelhead were from parents that produced few parr offspring, indicating that high production of parr offspring may not be related to greater returns of adult offspring. These data in combination with other studies of sympatric life histories of O. mykiss indicate that fluvial rainbow trout are important to the conservation and recovery of steelhead and should be included in the management and recovery efforts.

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

    Directory of Open Access Journals (Sweden)

    Claire Cousins


    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.

  20. Numerical model predictions of autogenic fluvial terraces and comparison to climate change expectations (United States)

    Limaye, Ajay B. S.; Lamb, Michael P.


    Terraces eroded into sediment (alluvial) and bedrock (strath) preserve an important history of river activity. River terraces are thought to form when a river switches from a period of slow vertical incision and valley widening to fast vertical incision and terrace abandonment. Consequently, terraces are often interpreted to reflect changing external drivers including tectonics, sea level, and climate. In contrast, the intrinsic unsteadiness of lateral migration in rivers may generate terraces even under constant rates of vertical incision without external forcing. To explore this mechanism, we simulate landscape evolution by a vertically incising, meandering river and isolate the age and geometry of autogenic river terraces. Modeled autogenic terraces form for a wide range of lateral and vertical incision rates and are often paired and longitudinally extensive for intermediate ratios of vertical-to-lateral erosion rate. Autogenic terraces have a characteristic reoccurrence time that scales with the time for relief generation. There is a preservation bias against older terraces due to reworking of previously visited parts of the valley. Evolving, spatial differences in bank strength between bedrock and sediment reduce terrace formation frequency and length, favor pairing, and can explain sublinear terrace margins at valley boundaries. Age differences and geometries for modeled autogenic terraces are consistent, in cases, with natural terraces and overlap with metrics commonly attributed to terrace formation due to climate change. We suggest a new phase space of terrace properties that may allow differentiation of autogenic terraces from terraces formed by external drivers.

  1. Implications of the fluvial history of the Wacheqsa River for hydrologic engineering and water use at Chavín de Húntar, Peru (United States)

    Contreras, Daniel A.; Keefer, David K.


    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.

  2. Legacies of Glacio-fluvial Interactions in the Finger Lakes, Central New York (United States)

    Safran, E. B.; Fountain, A. G.


    The Finger Lakes region of central New York exhibits spectacular examples of the interplay between glacial and fluvial processes. The Finger Lakes themselves were carved by ice sheets and related subglacial hydrologic processes that enlarged, over-deepened, and reversed the drainage direction of pre-existing fluvial valleys. The region's famous gorges flank the glacial troughs and reflect ongoing fluvial adjustment to glacially driven base level variations. Modern tools of topographic analysis permit quantification of the imprint that glacial processes leave on fluvial form and process. Regionally, ice sheet erosion is maximized along the north end of the Seneca/Cayuga trough. Local relief ranges from ~100 m at the north end of Seneca and Cayuga lakes to 250-400 m on the southern ends of these lakes and on the smaller, flanking lakes (Keuka, Canandaigua, Skaneateles, Owasco). Concavity indices for lake-tributary stream profiles are predominantly in the range of -7 to 0, reflecting a convex initial form imposed by glacial processes, while normalized channel steepness (ksn) indices are generally under 40 (reference concavity of 0.45), reflecting the gentle gradients of the glacial uplands. Concavity index and ksn values are maximized (>0, and >75, respectively) along short segments at the downstream ends of the so-called interglacial or post-glacial gorge reaches, again maximized at the southern and peripheral parts of the Seneca/Cayuga trough. Finally, streams that cross former channel courses buried by subglacial debris typically have more numerous and/or more pronounced knickpoints and more concave long profile segments than streams that do not. In short, the legacy of glaciations from the regional to the reach scale appears to be driving patterns of fluvial response in the Finger Lakes.

  3. Obesity and single-incision laparoscopic appendectomy in children. (United States)

    Litz, Cristen N; Farach, Sandra M; Danielson, Paul D; Chandler, Nicole M


    Single-incision laparoscopic appendectomy (SILA) has emerged as a less-invasive alternative to conventional laparoscopy. The purpose of this study was to assess the impact of body habitus on outcomes after SILA in the pediatric population. A retrospective review of 413 patients who underwent SILA from 2012 to 2015 was performed. Body mass index (BMI) was calculated, and the BMI percentile was obtained per Center for Disease Control guidelines. Standard definitions for overweight (BMI 85th-94th percentile) and obese (BMI > 95th percentile) were used. General demographic and outcome data were analyzed. SILA was performed in 413 patients during the study period, of which 66.3% were normal weight, 16% were overweight, and 17.7% were obese. There were no significant differences in age at presentation, time to diagnosis, or intraoperative classification of appendicitis. There were no significant differences in operative time (27.0 ± 9.1 versus 27 ± 9.8 versus 28.4 ± 9.4 min, P = 0.514), postoperative length of stay (0.97 ± 1.65 versus 1.53 ± 4.15 versus 1.14 ± 2.27 d, P = 0.214), 30-d surgical site infections (6.9% versus 12.1% versus 8.2%, P = 0.377), emergency department visits (8.4% versus 10.6% versus 11%, P = 0.726), or readmissions (4.7% versus 4.1% versus 4.5%, P = 0.967) among normal, overweight, and obese groups. Our results indicate that obesity does not significantly impact outcomes after SILA. SILA can be performed in overweight and obese children with no significant difference in operative time, length of stay, or incidence of surgical site infection. SILA should continue to be offered to overweight and obese children. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. 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


    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.

  5. 20G Vitrectomy conjunctiva micro-incision technique clinical application%20G玻璃体切割结膜微创切口技术应用分析

    Institute of Scientific and Technical Information of China (English)

    王文战; 郝娟; 杨惠春; 晁晓蕊


    Objective To evaluate the curative effect of clinical application of 20-gauge (20G) vitrectomy conjunctiva micro-incision technique.Methods The clinical data of 76 patients with vitreous retinal disease patients treated by the 20G vitrectomy conjunctiva micro-incision technique were retrospectively analyzed.Operative incision was divided into conjunctiva micro-incision group and convention vitrectomy group.When the operation was over-peripheral retina,only the incision for vitrectomy and light probe in conjunctiva micro-incision was sutured.All patients were followed up by 2-4months.Incision for bulbar conjunctiva and sclerotic was sutured in conventional vitrectomy.Conjunctival congestion,wound healing,intra-ocular tension,and operation running time were observed after operation.Results The mean operation time needed in conjunctiva micro-incision groups was 49minutes,while that in the conventional group was 61 minutes.There was statistical significance in the mean time of operation between two gronps.Bulbar conjunctiva superficies was smooth,sclerotic incision close was well,congestion and edema vanished in conjunctiva micro-incision group,while there was no significant difference in intra-ocular tension after operation between two groups.Conclusions Vitrectomy incision by using conjunctiva micro-incision has many advantages such as short operation time,micro-invasion and rapid recovery.It is worthy to be popularized.%目的 探讨20G玻璃体切割术(简称玻切)结膜微创切口技术临床应用的疗效.方法 回顾性分析76例76只眼应用20G结膜微创切口技术行玻切术治疗玻璃体视网膜疾病患者的临床资料.手术切口分为结膜微创切