Regional Drainage Research Articles

Patterns of nitrogen export from a seasonal freezing agricultural watershed during the thawing period

The objectives of this study were to investigate water, ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3−-N) export processes during the thawing period in a watershed with heavy agricultural activities and to evaluate contributions of N (i.e., NO3−-N and NH4+-N) from different source areas under different climate conditions. Experiments were conducted within the 75km2 agricultural Heidingzi watershed in northeast China. The thawing period was divided into four stages: early-melt, late-melt, rain-on-melt, and post-melt. Drainage regions (DRs) were separated into three types. The processes of water and N discharge from soil into rivers were monitored in these DRs during the thawing periods of 2014, 2015, and 2016. Results show that the processes of water and N discharge were not synchronous during the thawing period. Variations in discharge concentrations of NH4+-N and NO3−-N during the thawing period were mainly affected by the flushing effect, which was controlled by the physical state of the surface water (snow or ice) and the melt rate of frozen soil. Contributions of N export from the DRs varied under different land uses and climate conditions during the thawing period. NO3−-N export was mainly from maize fields. Thawing stages with high NO3−-N export were always accompanied by higher discharge rates. NH4+-N export mainly occurred during the early-melt and late-melt stages and from riverside rural regions.

Therapeutic evaluation between coventional fraction radiotherapy and intensity modulated radiation therapy combined with concurrent chemotherapy for esophageal carcinoma

Objective To evaluate the curative effect between conventional fraction radiotherapy (CFRT) and intensity modulated radiation therapy (IMRT) combined with concurrent chemotherapy for unresectable esophageal carcinoma. Methods 144 patients were enrolled into this study. They were divided into CFRT group and IMRT group. CFRT group (60 cases): irradiation field encompassed primary lesion and mediastinal lymph drainage regin. Neck and thoracic upper segment cases were made front thoraxT field irradiation first, DT 36 Gy/18 f, followed by two front oblique field made Iso-central irradiation, field width was 4.5-5.0 cm, gantry angle 50°-60°, wedge filter 30°, DT added to 66 Gy. For thorax middle or lower segment patients, field width was 6.0-6.5 cm, field length was that the tumor upper and lower each extended 3.0-5.0 cm, vertically irradiated in thoracic front and at the back, after DT 36 Gy/18 f, changed to two back ablique field, made Iso-central irradiation, DT added to 66 Gy. IMRT group (84 cases): GTV was esophageal primary lesion and metastasis lymph node (GTVnd); CTV included GTV, GTVnd and mediastinal lymph drainage region, at GTV around all was widened 0.8-1.0 cm, its upper and lower each extended 3.0-5.0 cm; PTV were in the basis of CTV, all were widened 0.5 cm again. With ≥95% isodose curve covering the PTV and the target dose was prescribed to PTV 60-64 Gy/30-32 f. Organ at risk (OAR): both lungs V20≤30%, spinal cord ≤45 Gy/6 weeks, heart V30≤40%. Chemotherapy of two groups was same, DDP 25-30 mg/m2 × 3-5 days, 5-Fu 450-500 mg/m2 × 5 days civ, 28 days were one period, total 2 period, after 1-3 months, strengthen chemotherapy 3-4 period. Results Leucopenia and radiation-induced esophagitis as shown by the WHO staging system were the most common acute toxicities, but were mainly grade 1 or 2. The incidence rate of leucopenia and radiation-induced esophagitis in CFRT group were 78.3% (47/60) and 83.3% (50/60), IMRT group were 82.1% (69/84) and 79.8% (67/84). After symptomatic treatment, all patients completed the planner treatment. During radiotherapy and after treatment, the patients showed grade 1-2 radiation-induced pneumonitis, CFRT group were 36.7% (22/60), but IMRT group were only 9.5% (8/84) (χ2= 9.99, P < 0.01). In CFRT group and IMRT group, the 1-, 3-, 5-year survival rates were 75.0% (45/60), 36.7% (22/60), 20.0% (17/84) and 79.8% (67/84), 35.7% (30/84), 21.4% (18/84), respectively. Conclusion The overall response and 5-year survival rates of CFRT and IMRT combined with concurrent chemotherapy are similar, however, the incidence of grade 1-2 radiation-induced pneumonitis of IMRT is low, which indicates that IMRT can reduce the lungs irradiational volume and dose. Key words: Esophageal neoplasms; Radiotherapy, intensity-modulated; Drug therapy; Radiation pneumonitis

Estimation of CHOPS Wormhole Coverage From Rate/Time Flow Behaviors

Summary In wormholed reservoirs with cold-heavy-oil-production-with-sand (CHOPS) wells, regions covered by wormhole networks are estimated by analyzing rate/time flow behaviors along with pressure and sand-production data. In this work, the concept of effective wormhole coverage is proposed as a proxy of the drainage region of CHOPS wells with complex wormhole networks. The wormhole intensity is defined as the total length of wormholes per unit effective wormhole coverage. A CHOPS flow model is developed by use of the boundary-element method (BEM) to account for various boundary conditions, wormhole morphologies, and effects of wormhole dynamic growth. Transient pressure and rate responses calculated by the model are validated by comparing with analytical solutions and numerical simulations. Modeling results show that the effective wormhole coverage and wormhole intensity within the region dominantly affect the characteristics of pressure and rate/time behaviors, regardless of the detailed wormhole morphologies. Accordingly, dimensionless pressure and rate type curves are developed to match flow behaviors, such as wormhole linear- and transitional-flow regimes to estimate effective wormhole coverage of CHOPS wells with available field data. This work extends the literature with fast type-curve matching of pressure and rate/time behaviors instead of generally practiced numerical-simulation routines. A field case with rate and sand-production data is successfully analyzed to show great potential of applying the proposed approach to characterize CHOPS wormholes.

River piracy and drainage basin reorganization led by climate-driven glacier retreat

River piracy—the diversion of the headwaters of one stream into another one—can dramatically change the routing of water and sediment, with a profound effect on landscape evolution. Stream piracy has been investigated in glacial environments, but so far it has mainly been studied over Quaternary or longer timescales. Here we document how retreat of Kaskawulsh Glacier—one of Canada’s largest glaciers—abruptly and radically altered the regional drainage pattern in spring 2016. We use a combination of hydrological measurements and drone-generated digital elevation models to show that in late May 2016, meltwater from the glacier was re-routed from discharge in a northward direction into the Bering Sea, to southward into the Pacific Ocean. Based on satellite image analysis and a signal-to-noise ratio as a metric of glacier retreat, we conclude that this instance of river piracy was due to post-industrial climate change. Rapid regional drainage reorganizations of this type can have profound downstream impacts on ecosystems, sediment and carbon budgets, and downstream communities that rely on a stable and sustained discharge. We suggest that the planforms of Slims and Kaskawulsh rivers will adjust in response to altered flows, and the future Kaskawulsh watershed will extend into the now-abandoned headwaters of Slims River and eventually capture the Kluane Lake drainage. River piracy—the diversion of one stream’s headwaters into another—has occurred on long timescales. An analysis of streamflow and digital elevation models documents river re-routing in response to glacier retreat in Yukon, Canada in May 2016.

PRELIMINARY RESULTS OF COMPLEX TREATMENT OF BREAST CANCER PATIENTS INCLUDING RECONSTRUCTIVE-PLASTIC SURGERY, CHEMOTHERAPY AND CONFORMAL RADIOTHERAPY

Preliminary results of complex treatment of 58 patients with I-IIIC breast cancer (T1-4N0-3M0) who underwent radical mastectomy with reconstruction of the breast in its various variants and conformal radiotherapy in adjuvant mode to the pectoral region and regional lymph drainage are presented in the article. A low incidence of complications from the reconstructed breast was noted: two (7 %) cases of implant removal due to pronounced capsular contracture and in connection with infection of the implant bed. At the time of observation of patients from 11.5 to 158.9 months, median 18.6 months, in 3 (5 %) patients clinically significant radiation pulmonitis was detected. The overall two-year survival was 97 % and progression-free survival was 90 %. In 6 (10 %) patients distant me-tastases were detected, in 1 (2 %) - recurrence of the disease in the area of postoperative scar. Thus reconstructive-plastic surgery can be an integral part of complex anti-tumor treatment including radiotherapy with direct indications to it in full volume and dose.

Investigation of Gravity-Driven Drainage and Forced Convective Drying in a Macroporous Medium Using Neutron Radiography

The co-occurrence of gravity-driven drainage and forced convective drying in a macroporous medium is investigated in this study. The drainage and drying processes of fully saturated porous asphalt (PA) specimens placed in a custom-made mini wind tunnel are documented with neutron radiography (NR). Six PA specimens of dimensions $$180\times 10\times 30\,\hbox {mm}^{3}$$ with a maximum aggregate size of 8 or 11 mm are used in the experiments. In the first few minutes of each experiment, there is significant moisture loss in all the specimens due to gravity-driven drainage. Most of the residual water retention is observed at the bottom region of the specimens due to the strong impact of gravity-driven drainage in the upper regions. The specimens are subjected to many hours of airflow at their top surface; however, forced convection from turbulent airflow near the upper part of the specimens is found to have a minor influence on moisture loss when there are no water clusters in the upper regions of the specimens. This points to the strong resistance to evaporation in PA as a result of the large vapor diffusion lengths. By combining neutron radiography and microcomputer tomography (X-ray $$\upmu $$ -CT) images, saturated and unsaturated flows in the pores are distinguished. Fluid flow path during air entry and water redistribution is further analyzed by reconstructing the real three-dimensional pore geometry of the specimens from X-ray $$\upmu $$ -CT scans.

Addressing the Influence of a Heterogeneous Matrix on Well Performance in Fractured Rocks

We address the influences of heterogeneity and complex geology of the matrix of fractured rocks on transient flow. Fractional constitutive flux laws reflect the stochastic framework that we consider. We model transient diffusion in both the matrix and fracture systems in terms of a continuous time random walk. Our procedure is particularly suited to address a complex geology that may exist on a number of scales and which may include dead ends and discontinuities. The performance of a horizontal well produced through arbitrarily located, multiple hydraulic fractures with distinct properties (length, width, permeability) forms the basis for our thesis. The pressure distribution in a rectangular drainage region where the well may be placed arbitrarily is expressed in terms of the Laplace transformation. The required solutions are obtained numerically. The focus of our work is on long-term behaviors for production at a constant pressure. In addition to numerical solutions, asymptotic results that provide information on the structure of the solutions are presented. Agreement between the asymptotic and numerical solutions is excellent. We show that long-term responses are governed by two distinct, two-parameter Mittag–Leffler functions and are an outcome of the complexities we desire to model in both the matrix and fracture systems. As a consequence, power-law behaviors that reflect the heterogeneity inherent in the system define long-time expectations. We show that the new solutions we derive do reduce to those of classical diffusion; that is, results corresponding to classical diffusion are a subset of the new results obtained here. Our results are particularly suited to model transient flow in shale reservoirs.

Analysis of Mountains Passes along the East-West Continental Divide and Other Drainage Divides Surrounding the Boulder River Drainage Basin, Jefferson County, Montana, USA

Detailed topographic maps of drainage divides surrounding the Jefferson County, Montana, Boulder River drainage basin were analyzed to determine the nature of drainage systems that preceded today’s Boulder River drainage system and how the Boulder River drainage system evolved from those earlier drainage systems. The Boulder River studied here drains in a north, east, and south direction to the Jefferson River, which at Three Forks, Montana joins the north-oriented Madison and Gallatin Rivers to form the north-oriented Missouri River. The North American east-west Continental Divide surrounds the Boulder River drainage basin western half and mountainous drainage divides with the Jefferson and Missouri Rivers surround the drainage basin’s eastern half. More than 25 deep mountain passes are notched into these drainage divides and provide evidence of the regional drainage system that preceded the present day Boulder River drainage system. Analysis of pass elevations and of orientations of valleys leading in opposite directions from those mountain passes shows that prior to Boulder River drainage system development immense volumes of south-oriented water moving in anastomosing complexes of diverging and converging channels flowed across the Boulder River drainage basin area and that the Boulder River drainage system evolved as deeper channels progressively captured flow from shallower channels. While not documented in detail crustal warping probably raised Boulder River drainage basin areas relative to adjacent valleys and basins as capture events took place. A water source was not determined, but may have been from a large North American continental ice sheet, although Boulder River drainage basin evolution probably occurred while mid Tertiary sediments were filling adjacent valleys and basins.

Fluvial archives, a valuable record of vertical crustal deformation

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 profile correlation, i.e., extrapolation of local data to entire profiles. Finally, planform changes in fluvial systems are considered at the channel scale in alluvial rivers and regional level in terms of drainage reorganisation. Examples are given of how numerical modelling can efficiently combine with topographic data to shed new light on the (dis)equilibrium state of drainage systems across regional drainage divides.

Monitoring bacterial indicators of water quality in a tidally influenced delta: A Sisyphean pursuit

The Sacramento-San Joaquin Delta Estuary (Delta) is the confluence of two major watersheds draining the Western Sierra Nevada mountains into the Central Valley of California, ultimately terminating into San Francisco Bay. We sampled 88 sites once a month for two years (2006–2008) over 87 separate sampling events for a total of 1740 samples. Water samples were analyzed for fecal indicator bacteria (Escherichia coli, enterococci and fecal coliforms), and 53 other physiochemical, land use, and environmental characteristics. The purpose of the study was to create a baseline of microbial water quality in the Delta and to identify various factors (climatic, land use, tidal, etc.) that were associated with elevated concentrations of indicator bacteria. Fecal indicator bacteria generally had weak to modest relationships to environmental conditions; the strength and direction of which varied for each microbial indicator, drainage region, and across seasons. Measured and unmeasured, site-specific effects accounted for large portions of variance in model predictions (ρ=0.086 to 0.255), indicating that spatial autocorrelation was a major component of water quality outcomes. The effects of tidal cycling and lack of connectivity between waterways and surrounding landscapes likely contributed to the lack of association between local land uses and microbial outcomes, though weak associations may also be indicative of mismatched spatiotemporal scales. The complex nature of this system necessitates continued monitoring and regular updates to statistical models designed to predict microbial water quality.

Venous drainage map of the liver for complex hepatobiliary surgery and liver transplantation

BackgroundInflow and outflow patency of the liver parenchyma is required to maximize the metabolic function of the liver. However, the definition and distribution of hepatic venous drainage regions has yet to be reported. The aim of this study was to define major hepatic venous tributaries and investigate the mean drainage volume of each territory. MethodsThree-dimensional (3D) simulations from the livers of 100 healthy donors were reviewed for living donor liver transplantation to determine the distribution of the significant hepatic venous tributaries and the drainage patterns of each segment. ResultsThe left hepatic vein (LHV), middle hepatic vein (MHV), and right hepatic vein (RHV) contributed a mean drainage of 20.7%, 32.7%, and 39.6% of the entire liver, respectively. Accessory hepatic veins accounted for remaining 7.0%. The middle right hepatic vein (MRHV) and inferior right hepatic vein (IRHV) accounted for a mean total drainage of 8.0% and 10.6%, respectively, when they present. In addition, major tributaries of hepatic veins were clearly detected, and their typical distributions were described. ConclusionsKnowledge of hepatic venous territories is necessary for complex hepatobiliary surgery. This “venous drainage map” may provide useful information for complex liver surgery and transplantation.

CH4 exchanges of the natural ecosystems in China during the past three decades: The role of wetland extent and its dynamics

AbstractCH4 is the second largest contributor to human‐induced global warming. However, large uncertainties still exist regarding the magnitude and temporal variation of CH4 exchanges in China's natural ecosystems, especially under climate changes. In this study, we assessed its uncertainty and temporal variation during 1979–2012, by integrating a biogeochemical model, extensive in situ measurements, and various sources of wetland maps. Uncertainty analyses suggested that previous studies might have underestimated CH4 emissions, primarily due to bias in wetland extents in NE China. After that, 1 km resolution wetland maps were used to drive the model, together with a 0.1° resolution climate data set. The model showed that China's natural wetlands emitted 4.56 ± 1.24 Tg CH4 yr−1 during the 1980s, which decreased to 3.86 ± 1.09 Tg CH4 yr−1 in the 2000s, mainly due to wetland drainage in NE China. However, recent glacier‐melt‐induced wetland expansion has enhanced CH4 emissions by 28% on the Tibetan Plateau since the 1980s. The magnitude of CH4 uptake by the natural ecosystems has remained relatively stable, e.g., −2.57 ± 0.18 and −2.70 ± 0.19 Tg CH4 yr−1 in the 1980s and 2000s, respectively. In summary, the net CH4 balance of China's natural ecosystems has shown a decreasing pattern, i.e., 1.99 ± 1.42 and 1.16 ± 1.28 Tg CH4 yr−1 in the 1980s and 2000s, respectively, despite distinct regional differences between NE China and the Tibetan Plateau. Furthermore, this study emphasizes the correct representation of wetland extent and its dynamics, i.e., wetland drainage in populated regions and wetland expansion in glacier‐fed regions, in driving the decadal CH4 exchange magnitude.

Surgical anatomy and regional drainage pattern of pancreatic ducts in the head and uncinate process of the pancreas: A cadaveric study

Surgical anatomy and regional drainage pattern of pancreatic ducts in the head and uncinate process of the pancreas: A cadaveric study

Rate Decline, Power Laws, and Subdiffusion in Fractured Rocks

Summary A 2D, mathematical model that considers transient flow under subdiffusion toward a horizontal well that produces a rectangular drainage region through multiple fractures is considered. Subdiffusive behavior expressed through a fractional constitutive flux law is intended to reflect a complex geology that may exist on a number of scales in the form of obstacles and channels as well as attendant changes induced by hydraulic fracturing, and considers transient diffusion as a continuous time random walk (CTRW). The hydraulic fractures intersect the horizontal well at arbitrary locations with distinct properties (length, width, permeability). Pressure distributions expressed in terms of the Laplace transformation are inverted numerically. Computational issues are addressed, and numerical solutions are compared with asymptotic results. The focus of the work is on the boundary-dominated period for production at a constant pressure. Long-time responses described in terms of a two-parameter Mittag-Leffler function lead to a decline in rate that exhibits power-law behavior—an outcome of a complex geological structure with significant variations in properties (i.e., a complex geology in which cracks, fissures, and discontinuities abound). Conventional expectations of an exponential decline that until now has been the norm for the flow of a slightly compressible liquid in bounded regions are a subset of the results presented here.

Postoperative radiotherapy combined with concurrent paclitaxel-nedaplatin chemotherapy for esophageal cancer: a preliminary study

Objective To investigate the safety and preliminary effect of postoperative intensity-modulated radiotherapy (IMRT) combined with concurrent weekly paclitaxel-nedaplatin chemotherapy for patients with esophageal squamous cell carcinoma. Methods A total of 52 patients who were treated from 2010 to 2013 were enrolled. The clinical target volume of IMRT included tumor beds and corresponding lymphatic drainage regions at high risk, and the total radiotherapy dose was 50-60 Gy, 2.0 Gy/fraction, 5 fractions per week. The concurrent chemotherapy consisted of nedaplatin 25 mg/m2 on D1 and paclitaxel 45-50 mg/m2 on D1 and was repeated every week during radiotherapy. Common Terminology Criteria for Adverse Events 4.0 was used to evaluate adverse events, and the Kaplan-Meier method was used for survival analysis. Results All the patients had good tolerance to the treatment, and 51 patients (98%) completed radiotherapy according to the scheduled regimen. The median number of chemotherapy cycles was 4, and 42 patients (81%) completed ≥3 cycles of chemotherapy. Most adverse events were of grade 1-2, and grade 3 adverse events were leucopenia (29%), radiation esophagitis (10%), and anastomotic stenosis (4%). One patient (2%) experienced grade 5 gastroesophageal bleeding. Of all the patients, the median survival time was 38.7 months, and the 1-, 2-, 3-, and 4-year overall survival rates were 83%, 64%, 51%, and 38%, respectively. The overall recurrence rate was 46.2%, and the locoregional recurrence rate and distant metastasis rate were 15% and 37%, respectively. Conclusions Postoperative IMRT combined with concurrent weekly paclitaxel-nedaplatin chemotherapy for patients with esophageal squamous cell carcinoma is safe and effective, and large-scale prospective randomized studies are needed. Key words: Esophageal neoplasms/radiochemotherapy; Radiochemotherapy, concurrent; Efficacy; Security

Insights into surface runoff on early Mars from paleolake basin morphology and stratigraphy

We present observations on the morphology and stratigraphy of more than 400 paleolake basins on Mars. We show that there are two distinct classes of Martian paleolake basins: (1) paleolakes fed by regionally integrated valley networks (N = 251), and (2) paleolakes fed by isolated inlet valleys not integrated into broader regional drainage systems (N = 174). We conclude that valley network–fed paleolakes primarily formed prior to approximately the Noachian-Hesperian boundary, ca. 3.7 Ga, while isolated inlet valley paleolakes primarily formed later in Martian history. All 174 isolated inlet valley paleolakes are closed-basin lakes; however, there are surprisingly few (31) valley network–fed closed-basin lakes compared to a large number (220) of valley network–fed open-basin lakes. This observation is consistent with declining levels of fluvial activity over time on the Martian surface. Our results imply that during the era of valley network formation, ∼90% of topographic basins breached by an inlet valley had sufficiently high ratios of water influx to losses to fill, overtop, and form an outlet valley. This conclusion provides an important constraint on the balance between surface runoff production and water losses on early Mars that must be satisfied by any model of the early Martian climate and hydrologic cycle.

Variability and Trends in Precipitation, Temperature and Drought Indices in the State of California

This study presents a comprehensive assessment of the variability and trends of the precipitation and temperature along with the trends in drought indices over the State of California. The non-parametric Mann–Kendall trend test is applied with a trend-free pre-whitening procedure in trend identification. A dataset containing 120-year (water years 1896–2015) monthly precipitation, average temperature, maximum temperature, minimum temperature and the Palmer Index for seven climatic regions of the state is used for this purpose. The results confirm previous work indicating that no clear trends are observed in precipitation, while a distinct warming trend is evident in temperature over the state. New findings of this study include: (1) in general, the variability of annual, winter (December–February) and spring (March–May) precipitation shows an increasing tendency, implying intensified frequency of the occurrence of dry or wet extremes; (2) on the annual scale and in the summer, statewide meteorological, hydrological and agricultural drought indices all have decreasing trends, indicating the more frequent occurrence of drought events; and (3) among seven regions, the South Coast Drainage region generally has the most significant warming trend, as well as the most significant declining trends in drought indices. Overall, these findings are highly meaningful from both theoretical and practical perspectives, in the context of providing critical information in developing prediction models and guiding water resources management practices, respectively.

The provenance and setting of the Mesoproterozoic Dala Sandstone, western Sweden, and paleogeographic implications for southwestern Fennoscandia

The Mesoproterozoic (Jotnian) Dala Sandstone, western Sweden, is investigated using zircon U-Pb SIMS. The Dala Sandstone was deposited in a gentle sag basin and underwent post-depositional downfaulting and local deformation along the Sveconorwegian Frontal Deformation Zone. The maximum depositional age is lowered to 1.58Ga, lending support to a suggested 1.5Ga maximum age from regional basement age considerations. Associated 1.46Ga volcanism (Öje basalt) indicates that the 1.5–1.4Ga Hallandian-Danopolonian event triggered basin formation; in addition, repeated local magmatism and deformation over several 100m.y. hint at the presence of a crustal weak zone. Provenance data indicate sediment sources in surrounding Svecofennian, Transscandinavian Igneous Belt and Gothian domains; age peaks coinciding with early Gothian phases suggest that older inboard parts of the orogen shielded the Dala region from the younger outboard parts. Decreasing input from the Gothian orogen after 1.46Ga suggests changing regional drainage patterns. Archaean/Paleoproterozoic zircon in pre-Sveconorwegian sediments in southern Norway is proposed to reflect sediment routing from the north, or significant sinistral Sveconorwegian displacement of southern Norway along the Fennoscandian margin. The latter would potentially juxtapose the Dala basin and the Rjukan rift in southern Norway, however, these formed two distinct and separate basins.

The practice of DEM stream burning revisited

AbstractStream burning is a common flow enforcement technique used to correct surface drainage patterns derived from digital elevation models (DEM). The technique involves adjusting the elevations of grid cells that are coincident with the features of a vector hydrography layer. This paper focuses on the problematic issues with common stream burning practices, particularly the topological errors resulting from the mismatched scales of the hydrography and DEM data sets. A novel alternative stream burning method is described and tested using five DEMs of varying resolutions (1 to 30 arc‐seconds) for an extensive area of southwestern Ontario, Canada. This TopologicalBreachBurn method uses total upstream channel length (TUCL) to prune the vector hydrography layer to a level of detail that matches the raster DEM grid resolution. Network pruning reduces the occurrence of erroneous stream piracy caused by the rasterization of multiple stream links to the same DEM grid cell. The algorithm also restricts flow within individual stream reaches, further reducing erroneous stream piracy. In situations where two vector stream features occupy the same grid cell, the new tool ensures that the larger stream, designated by higher TUCL, is given priority. TUCL‐based priority minimizes the impact of the topological errors that occur during the stream rasterization process on modeled regional drainage patterns. The test data demonstrated that TopologicalBreachBurn produces highly accurate and scale‐insensitive drainage patterns and watershed boundaries. The drainage divides of four large watersheds within the study region that were delineated from the TopologicalBreachBurn‐processed DEMs were found to be highly accurate when compared with the official watershed boundaries, even at the coarsest grid resolutions, with Kappa index of agreement values ranging from 0.952 to 0.921. The corresponding Kappa coefficient values for a traditional stream burning method (FillBurn) ranged from 0.953 to 0.490, demonstrating a significant decrease in mapping accuracy at coarser DEM grid resolutions. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Regional drainage pattern and spatial arrangement of pancreatic ducts in the head and uncinate process of the pancreas: A cadaveric study from India

Regional drainage pattern and spatial arrangement of pancreatic ducts in the head and uncinate process of the pancreas: A cadaveric study from India