Lateral Bars Research Articles

Evolution and hydro-stratigraphy of the coastal aquifer in Garopaba/SC: Interpretation from georadar and tubular wells

This work analyzes the geological evolution of sedimentary deposits in the coastal aquifer of Garopaba, south Brazil, using ground penetrating radar (GPR) and data from tubular wells. The aquifer is localized in the coastal plain, where Quaternary lagoon-barrier environments are set between the Precambrian crystalline mountains and the sea. Over ten tubular wells are scattered in urbanized areas, which highlights the vulnerability of the unconfined, granular shallow aquifer. The results show that the aquifer has lithologic units of local scale. Tubular well data show the basal limit of the aquifer overlying clayey layers between 30 and 40 m deep and intercalation of sand layers up to the surface, mostly fine to very fine sand, with metric thickness, secondary lenses of clay and minor occurrence of gravel. The radarfacies interpretation shows fluvial-estuarine deposits as a local hydrostratigraphic unit, with lateral accretion bars filling a NE-axis paleochannel. The basal surface of the channel is interpreted as the sequence boundary surface of the lagoon-barrier systems III (upper Pleistocene) and IV (Holocene). The geological evolution of the aquifer is related to the upper Pleistocene marine regression (120–18 ka), that caused the aerial exposure of the continental shelf, and the development of complex drainage channels, which were superimposed during the Holocene transgression by lagoon-barrier IV deposits. After the post-glacial transgression, the lowering of the RSL to the current level promoted the silting of part of the lagoon system by continental sedimentation and aeolian deposits composing the surface.

Operative Management of Pediatric Physeal Bar Development and Genu Valgum.

Pediatric orthopedic conditions present unique challenges due to ongoing skeletal growth and development. Managing these cases requires addressing both structural anomalies and functional deficits. This case report discusses a 13-year-old male with recurrent left knee pain exacerbated by physical activity. The patient's history of a left knee infection at 1.5 years of age, possibly septic arthritis or osteomyelitis, underscores the long-term consequences of early pathology on skeletal growth and alignment. Imaging studies revealed a distal lateral femur physis bar and genu valgum, necessitating surgical intervention. The surgery involved medial distal femur hemiepiphysiodesis and lateral distal femur bar excision to correct anatomical deformities and restore optimal limb alignment and function. Postoperative rehabilitation, including targeted exercises to improve quadriceps strength, was crucial for functional recovery and reducing the risk of complications such as medial patellofemoral pain. This case highlights the importance of a multidisciplinary approach in managing complex pediatric orthopedic cases.

ROSES: The most Complete System for Endovascular Surgery

ROSES, an innovative Robotic System for Endovascular Surgery, features a unique mechanism that continuously measures the resistance encountered by catheters and guide wires as they advance within the body. This feature operates seamlessly without the need for additional specialized components. The system is comprised of a series of robotic actuators (up to three) arranged linearly on slides running along a rail, inclined toward the patient. Another slide, housing a pair of step motors, facilitates the adjustment of relative positions between the actuators, with the proximal actuator affixed to the motor slide by a lateral bar. A force transducer, linked to the motor slide via a wire, is responsive to the gravitational component of any object on the rail. Importantly, this force remains constant even as the actuators move. However, the force dynamically changes if an external obstruction hinders the progress of catheters and guide wires, serving as an alert to the attending physician. The system, uniquely, is also capable of guiding the introduction of the first catheter, even if it is pre-curved. This capability facilitates the complete separation of the doctor from the patient throughout the entire surgical procedure. The system employs compact, purely mechanical disposables designed for a wide range of interventions utilizing commercially available catheters and guide wires, including angioplasty, brain and carotid surgery (for aneurysms or thrombi), TAVI, and various lower and upper limb procedures. Future developments include the incorporation of animated catheters capable of altering their shape configuration under console control. As the system also records the penetration length of each device and transmits this data to a workstation along with X-ray images, it effectively becomes the "black box" of endovascular surgeries. This functionality allows for a complete separation between physicians and patients throughout the entire surgical procedure. The system is safeguarded by multiple pending international patent applications.

Fracture of four semi-regular lattices regulated by T-stress in modified boundary layer models

The development of additive manufacturing technology has promoted the rise of various lattice metamaterials, and evaluating their fracture properties is critical for both application and safety. Here, by conducting finite element simulations on four types of elastic-brittle semi-regular lattices (kagome, snub-trihexagonal, elongated-triangular, and snub-square), we indicate that the fracture toughness of lattice metamaterials is not solely determined by the crack-tip singular term, i.e., the critical stress intensity factor, but is also influenced by the non-singular T-stress term. T-stress regulates fracture toughness by modulating geometrical distortions and force-carrying modes of lattice bars around the crack front. This regulation effect depends on the lattice topology and becomes weaker under mixed-mode loading. As the relative density of lattices decreases, T-stress can force elastic buckling of bars around the crack front, which may deteriorate the fracture toughness. Additionally, positive T-stress tends to promote the crack deflection and negative T-stress tends to inhibit. Our results offer new insights into the structure-property relationships in the presence of T-stress, which may contribute to design the geometry of micro/nano-lattice metamaterials.

Short‐term biogeomorphology of a gravel‐bed river: Integrating remote sensing with hydraulic modelling and field analysis

AbstractIn recent decades, fluvial geomorphology and ecohydraulic research have extensively used field observations, remote sensing or hydrodynamic modelling to understand river systems. This study presents an innovative approach that combines field surveys, Light Detection and Ranging (LiDAR)‐based topographical and biomass analyses and model‐derived hydro‐morphodynamic geostatistics to examine short‐term biogeomorphological changes in the wandering gravel‐bed Orco River in Italy. Our primary hypothesis is that hydro‐morphological variables can be robust descriptors for riparian vegetation distribution. From a geomorphological perspective, our study confirms the prevalent wandering behaviour of the Orco River. Moreover, we identified a widening trend in braiding and anabranching sections, particularly downstream. This is evident because of hotspots of flood‐induced morphological reactivation and the redistribution of sediments from the riverbed to lateral bars, resulting in a multi‐thread pattern. Our analysis reveals a net increase in biomass during the observation period despite frequent flood disturbances. We attributed it to two opposing biogeomorphological dynamics: the reduced flow disturbance in some regions due to flood‐induced geomorphological changes and the self‐healing of lateral connectivity through river wandering. Such a net increase indicates that transitional rivers store carbon in the form of vegetation biomass due to their short‐term morphological instability and the different timescales between vegetation and morphological adjustments. Finally, we supported our initial hypothesis with three key findings: (i) a signature of vegetation not just on topography but also on hydro‐morphological conditions, summarised by inundation probability; (ii) the lower variance in vertical topographical changes in vegetated areas compared with bare ones; and (iii) the introduction of a new parameter, named inundation viscosity, derived from the product of mean bed shear stress and average inundation duration, as a discriminating factor for colonisation conditions. These results underscore the value of our comprehensive approach.

Study on the performance of a novel 1DOF isolator with QZS characteristics

A typical one-degree-of-freedom (1DOF) shock isolator that has quasi-zero stiffness (QZS) characteristics consists of two transversal springs and one portrait spring. The transversal springs can provide negative stiffness and the vertical spring is used as a load-bearing component. In this article, an improved 1DOF QZS shock isolator is obtained by utilizing the combination of lateral bars and springs. The displacement transmissibility under the harmonic excitation is obtained and the principle of minimum displacement transmissibility under the condition of system stability is proposed. Finally, numerical simulation is conducted, and the simulation results reflect that the proposed 1DOF QZS isolator significantly performs better than the previous one.

Multi-objective optimization design of anti-roll torsion bar using improved beluga whale optimization algorithm

PurposeThis study aims to reduce the redundant weight of the anti-roll torsion bar brought by the traditional empirical design and improving its strength and stiffness.Design/methodology/approachBased on the finite element approach coupled with the improved beluga whale optimization (IBWO) algorithm, a collaborative optimization method is suggested to optimize the design of the anti-roll torsion bar structure and weight. The dimensions and material properties of the torsion bar were defined as random variables, and the torsion bar's mass and strength were investigated using finite elements. Then, chaotic mapping and differential evolution (DE) operators are introduced to improve the beluga whale optimization (BWO) algorithm and run case studies.FindingsThe findings demonstrate that the IBWO has superior solution set distribution uniformity, convergence speed, solution correctness and stability than the BWO. The IBWO algorithm is used to optimize the anti-roll torsion bar design. The error between the optimization and finite element simulation results was less than 1%. The weight of the optimized anti-roll torsion bar was lessened by 4%, the maximum stress was reduced by 35% and the stiffness was increased by 1.9%.Originality/valueThe study provides a methodological reference for the simulation optimization process of the lateral anti-roll torsion bar.

Geomorphologic evidences and hydrologic reconstruction of Holocene catastrophic flood events in the Yarlung Tsangpo Grand Canyon, Eastern Himalaya

Catastrophic floods from breaching of natural dams on the Namche Barwa and Giala Peri play an important role in shaping high-mountain landforms in the eastern Himalayan syntaxis. However, there is limited knowledge of geomorphologic evidences and magnitude of outburst flooding in the Yarlung Tsangpo Grand Canyon. In this paper, geomorphic impacts of high-magnitude outburst floods (104–106 m3/s) were analyzed using palaeoflood hydrology technology. Well-preserved 2018 Sedongpu (SDP) flood and 2000 Yigong (YG) flood sand bars are charactered by grey sands with parallel laminations, whereas megaflood geomorphic evidences in the Grand Canyon are dominated by massive slackwater deposits and lateral gravel bars. The palaeoflood events were dated to 4.3–2.4 ka, corresponding to the known Holocene megafloods in the lower Yarlung Tsangpo River. These flood ages are obviously younger than most of remnant lacustrine deposits during the late Pleistocene, but consistent with the ages in the top part of palaeolake and glacial moraines of the Namche Barwa. The chronological data help to confirm the highest probability phases of outburst floods from moraine-dammed lakes. The repeated megaflood peak discharges range from 0.5 to 1.1 × 106 m3/s, which are approximately 5–10 times greater than the maximum peak discharge of 2000 YG flood (9.5 × 104 m3/s) and 20–40 times than that of 2018 SDP flood (2.5 × 104 m3/s) in the Medog reach. Megaflood waters are always deepest (∼200 m) and fastest (∼50 m/s), which are at least twice times larger than 2000 YG flood. Higher shear stress (>3.3 kPa) and stream power per unit area (>168 kw/m2) occurred in narrower channel and sharp bend with higher velocity. Our model also predicts some potential erosion and deposition landscapes resulted from floodwaters routing through the Grand Canyon. These results address the geomorphic impacts of catastrophic flood events with magnitudes (104–106 m3/s) in the Yarlung Tsangpo Grand Canyon. Our new palaeoflood geomorphologic evidences provide a key constraint on the age and magnitude of Holocene megafloods in the largest Himalayan River.

Coastal beaver, Chinook, coho, chum salmon and trout response to nearshore changes resulting from diking and large-scale dam removals: synergistic ecosystem engineering and restoration in the coastal zone

In this paper we assess long-term trends and habitat changes to understand the relationships between coastal beaver (Castor canadensis), salmon, shoreline alterations, large-scale dam removals and nearshore ecological restoration. From this work we conclude that the removal of two large scale dams in the Elwha River has benefited beaver use of the coastal zone through water quality changes that allow beaver to re-establish high-quality zones and the expansion of riparian zones that provide extensive new food resources to beaver. However, the lower river hydrodynamic processes continue to be disrupted by a 200-meter earthen dike installed by local government and landowners for flood protection in the Elwha coastal zone in the 1960’s. The dike acts as a driver of lower river geomorphology and has resulted in the formation of a large and persistent lateral bar along the lower river channel. Associated disrupted hydrodynamics are causing a critical coastal zone of the unimpounded lower river side channels to fill in. This channel habitat has decreased by 23%, with an annual average shrinkage rate of 13%, from pre-dam removal size, resulting in a decrease in both quality and quantity of nursery function for juvenile wild fish in a coastal zone that was historically documented to be the highest functioning for endangered juvenile salmon and trout. Inversely, physical changes including improved water quality in the adjacent impounded west side channel and continued expansion of riparian vegetation along the west delta lateral bar benefitted coastal beaver that recolonized the west delta after dam removals. The newly colonized coastal beaver may provide ecological engineering services to offset side channel loss as well as promote continued fish access. However recreational use was found to negatively impact beaver use of the area. We therefore recommend a series of additional ecosystem restoration actions that incorporate beaver as an ecosystem restoration component of the coastal zone. These actions include a public outreach program to encourage passive recreation measures to prevent negative impacts to beaver, and legacy, ecosystem scale restoration projects that reconnect the hydrodynamics of the west delta to complete Elwha ecosystem restoration. Together, these steps, if implemented, will result in a synergistic ecosystem restoration throughout the watershed to the benefit of the coastal ecosystem, including both beaver and salmon, as intended by the large-scale dam removal project.

Biogeomorphic recovery of a river reach affected by mining

AbstractEnvironmental changes are impacting river systems worldwide. These arise from factors such as flood magnitude–frequency changes, direct human management interventions, inadvertent human impacts on sediment supply and fluvial regimes and landscape‐scale changes in climate. Historical and active metal mining is significant in this regard. Here, we investigate morphodynamic changes within a reach of the River Ystwyth, Wales, since 1845. We analyse historical and contemporary information derived from maps, river flow records (1962–2021), metal analyses of sediment samples (1970s and 2021), ground geomorphological surveys (1970s and 1986–1987) and remotely sensed imagery (2001–2021) to investigate changes during a period of active metal mining followed by a century of post‐mining recovery. During the studied period, an initially meandering river was transformed into a braided one, subsequently reverting to a single sinuous channel. Sinuosity reduced from 1.31 in 1845 to 1.09 in 1982 before recovering to 1.39 in 2019. Inversely, the braiding index reduced from a maximum of 2.0 in 1987 to 1.5 in 2021. Evolution in planform was associated with a change from expansive bar formation and avulsion under braided conditions to lateral bar accretion and associated bank erosion along a sinuous single channel. The initial 19th‐century channel pattern and floodplain instability seems to have been related to mining sediment toxicity effects rather than a response to high sediment volumes, with recent recovery and channel style reversion being attributable to vegetation encroachment and biomass stabilization of the floodplain. Causal factors of recent recovery appear to be colonization by gorse (Ulex europeaus) in the absence of physical control measures and a reduction in grazing by the native rabbit population because of a disease‐induced decline in their numbers. These results highlight the importance of riparian vegetation in addition to sediment balance and hydrological processes in controlling fluvial responses to environmental changes.

The polygenetic floodplain of the Upper Paraná River

The mega-river functions differently from ordinary rivers and its floodplain is characterized by its magnitude, morphological complexity, and evolutionary history. This study analyzes the morphological and evolutionary characteristics of the Upper Paraná mega-river floodplain (Qm 13,000 m3 s−1), characterizing it as polygenetic owing to the various formative processes involved, many of which are no longer active and have extended since the end of the Pleistocene. The Upper Paraná floodplain is adjacent to the channel and in-channel on the large islands of its lower section. The 235 km study reach river has anabranching stretches that are separated by nodal sections. The analysis used satellite images, aerial photographs, 35 colors, and 52 absolute dates. Four types of floodplains were characterized: inherited, formed by processes and morphologies no longer active in the system; bayfill, formed by overflow deposits in flooded areas; crest-and-trough, by the annexation of lateral bars; and mixed, by the combination of the types above and association of the Paraná floodplain with its tributaries. Floodplain formation occurred in three phases. 1) At the end of the Pleistocene when the river developed a braided sand-gravel pattern under a dry climate. 2) It began at the Pleistocene-Holocene limit, when climatic improvement produced hydrological changes in the river leading to the vertical and lateral excavation of the old floodplain, generating a new channel and a sandy terrace 10 m above the current river level. The formation of the current floodplain began in this phase with the abandonment of the pioneer lake-islands. 3) It started with a small semi-arid event in the mid-Holocene until the present. The current floodplain and river hydrology were defined in this phase. Tectonic interventions for forming the floodplain are also addressed in the text. Considering its varied origin, the floodplain is polygenetic, implying a complex mosaic of environments whose connectivity relationships are still unknown. We believe that the concept of polygenetic floodplains presented in this study will help the understanding of hydrological and ecological functioning of the polygenetic floodplains of tropical mega-rivers.

Universalization of the elastic system of vibration feeders with vertical electromagnetic vibration drive

Vibrating feed bins with electromagnetic drive are widely used in the automation of production processes in mechanical engineering and instrument engineering. They are used for feeding miniature, small, or medium-sized parts to automated production equipment. This equipment is used in automatic lines, automated complexes, or any other flexible automated production facilities. These devices are most widely used for loading parts to assembly positions in automated assembly complexes. In this case, the parts fed to these positions must be located in a certain stable position. Various orientation tools are used for this purpose. They are located directly on the transport trays in the bins of these devices. Therefore, for reliable operation of orientation devices, the movement of parts on the trays should be smooth without sensitive tossing. The designs of vibrating hopper feeders with a hopper connected to a reactive plate by a directional elastic system in the form of a lattice torsion bar are considered. An electromagnetic vibration exciter is placed between the torsion flanges. The disadvantage of such vibration feeders is low productivity in operating modes, especially when there are increased requirements for the smooth movement of transported parts. An increase in the productivity of such feeders is carried out by increasing the amplitude of hopper vibrations in the direction of movement of parts, that is, the horizontal component of vibrations. However, this also leads to an increase in the vertical component, since vibrations are carried out at an angle to the feeder transport tray. When the vertical component of vibrations increases, the transportation of parts switches to the intensive tossing mode. A further increase in the oscillation amplitude leads to a violation of the normal mode of vibrational transport. Modern production involves the modernization of existing structures, as well as the creation of new models of machines with high technical and economic indicators Therefore, the universalization of existing equipment and the development of new machine schemes is an important task for developers and manufacturers of technological equipment, since even a minimal improvement in its technological or operational indicators can lead to a significant economic effect. The paper considers a complex of additional elements used that make it possible to universalize the design of vibrating hopper feeders with electromagnetic drives having a directional elastic system. These changes make it possible to adjust the horizontal component of the device hopper vibrations at a constant vertical one. Additional structural elements are proposed that increase the range of application of such feeders.

Recent geomorphological evolution of channel bar in Magdalena River (Colombia) due to natural and anthropogenic interferences

The growing establishment of port structures in estuarine regions has resulted in alternated sedimentation patterns and new geoforms. The primary purpose of this study is to understand the recent formation and geomorphological evolution of the fluvial bar in the final portion of the Magdalena River. The geomorphological evolution analysis was made possible using Geographic Information Systems tools, satellite images, and bathymetric data. The studied bar formed and stabilized through anthropic and natural factors such as port structures (obstacles to sediment transport), channel morphology, and natural- and anthropic-caused variation to the sediment supply. The lateral bar formation, adjacent to port structures, began in 2017 with surface runoff accumulating and anchored on the riverbank since 2018. At present, the bar covers 45% of the original river width, and an approximate sediment volume worth 4,000,000 m3 has accumulated. Changes in the navigable channel result in slope modification from 2.02° to 5.36°. The construction of port structures, i.e. new pile bridges, changes the natural sediment flow, because they are obstacles, trapping sediments downstream. This period coincides with the end of a weak El Niño cycle, subsequent to a La Nina period also of low intensity, with reduced precipitation rates resulting in a decrease in flow, and therefore contributing to an increase in sedimentation. The observations suggest that it is crucial to understand the channel bars' morphology and origin to avoid possible economic and social impacts due to the disruptions in navigation.

Fluvial-aeolian interaction deposits in the Andean Foreland basin (Northwest Argentina): Architecture and facies model

• Multiscale analysis of an aeolian-fluvial interaction field. • Work field analysis and GPR images were used for medium-scale analysis. • Granulometric and microscopy interpretation were used for medium and small scale. • An architectural model was proposed using all these methods. • Fluvial-aeolian interaction deposits are divided into dry, intermediate, and wet. The fluvial-aeolian interaction field of the Guandacol valley (northwest Argentina) is studied through different methodologies that comprise satellite, drone and GPR images, bedform descriptions, and grain-size analysis. The obtained information allowed the recognition of five depositional subenvironments: 1. Dune patches; 2. Aeolian sand sheets; 3. Muddy plains; 4. Active channels; and 5. Abandoned and secondary channels. Moreover, the lithofacies pattern, sedimentary structures and geometry of the beds permitted the definition of ten architectural elements in both channel and interchannel areas. The channel architectural elements comprise active channels with intercalations of aeolian deposits (CHe), abandoned or secondary channels (CHa), aeolian sand ramp (CHsr), lateral bars (CHlb), and aeolian mesoforms (CHem). The architectural elements in the interchannel area include active dunes (Fad), fixed or low-migration rate dunes (Fsd), partially flooded interdunes (Ffd), sandy flats (Fsf), and muddy plains (Fmp). A model of the evolution of fluvial-aeolian interaction environment is proposed in which three types are recognized: dry, intermediate, and wet. Migratory dunes and sand sheets environments dominate the dry interaction systems in the floodplain (Fad, Fsf). At the same time, during the intermediate stage, Fsd and Fsf architectures prevail, together with fluvial bars with thin aeolian intercalations into the channels (CHe and CHa). The wet systems consist of flooded interdunes, muddy plains, and different types of aeolian mesoforms in the channel (Fmp, Ffd and CHem). The analysis of present-day depositional subenvironments in the Guandacol valley and the definition of architectural elements serve as a potential analogue for studying ancient fluvial-aeolian interaction environments.

Variable amplitude cyclic bond behavior of deformed bars in concrete under uniaxial lateral pressures

The reversed cyclic bond behaviour between steel bar and concrete is critical to simulate the hysteretic response of reinforced concrete structures suffering from seismic loading and the bond behaviour is also greatly influenced by the stress field around the bond region. The objective of this study is to investigate the influence of uniaxial lateral confinement on the bond response of deformed bars in concrete under variable-amplitude reversed cyclic loading. The effect of lateral pressure and bar diameter on the bond parameters under reversed loading were evaluated. In addition, a hysteretic bond stress-slip constitutive model considering the uniaxial lateral confinement was proposed and validated with the test results.

Modelling and mapping of soil erosion in the north-eastern frontier Himalayan ranges of India using remote sensing and GIS

Soil erosion is a land degradable problem cause by natural resources. In context of North Eastern Himalayan ranges, it is a common soil degradation process due to fragile nature of soil and ecosystem. The aim of this study is to assess the soil erosion of Mahadevpur block, Namsai district of Arunachal Pradesh by RUSLE method using remote sensing and GIS environment. In this study, Sentinel 2 data of the study area was used to prepare land use/land cover (LU/LC) map by visual interpretation technique and ALOS digital elevation model (DEM) was used to develop slope, contour, flow direction and flow accumulation maps. Thematic raster layers of RUSLE factors (R, K, LS, C and P) were computed and used to estimate average annual soil loss by ArcGIS 10.3 software. The results showed that maximum area was (37.10%) under very slight soil loss class (< 5.0 t ha-1 yr-1). However, the extremely severe soil loss(> 80.0 t ha-1 yr-1) was observed in 7.0 % of the study area which was confined to terrain features such as lateral bar, meander scar, point bar, braided bar and channel bar. It was proved that, use of geospatial technologies in combination with RUSLE is a comprehensive approach, which helped in spatial assessment of soil erosion for better resource planning and taking up suitable conservation measures.

Еволюція методик хірургічної корекції лійкоподібної деформації грудної клітки в дітей: одноцентровий досвід

Pectus excavatum (PE) in children is the most common pathology among orthopedic diseases of the anterior chest wall. Today in the world the main direction of scientific research in the surgical correction of this pathology is safety during surgery for the patient and the introduction of minimally invasive techniques. Purpose – to conduct a comparative analysis of the results of thoracoplasty in children with PE using different surgical techniques to reduce trauma and duration of surgery and blood loss; to study the optimal correction results to accelerate psycho-physical adaptation after the Nuss procedure. Materials and methods. The treatment of 289 patients operated on for PE in the orthopedic and traumatology department of National Children’s Specialized Hospital «OKHMATDYT» were analyzed. According to the methods of thoracoplasty used, patients were divided into 3 groups. In the first group (n=112) PE correction was performed using Nuss operation with subxiphoid access and tactile control during the retrosternal bar placement; in the second group (n=79) Nuss procedure was performed under thoracoscopic control, where one retrosternal T-shaped bar with additional lateral stabilizer was implanted and fixed on the ribs with a resorbable suture or wire; in the third group (n=98) surgical treatment of PE was performed using the Nuss procedure under thoracoscopic control using a fixator consisting of two retrosternal bars-arches, which are interconnected by lateral bars, the «Bridge» technique. Results. When using thoracoscopic control and temporary sternum elevation by modificated «Park crane» during the correction of PE, the time of surgery and blood loss was reduced. No rotations of the fixator throughout the observation period and lower postoperative pain syndrome were observed in patients of the 3rd group, who underwent corrections with the «Bridge technique». Conclusions. The technique of minimally invasive correction of pectus excavatum (MIRPE), Nuss operation, using thoracoscopic control and temporary elevation of the sternum during pectus bar placement is a safe and effective method of thoracoplasty. The use of two plates (the «Bridge» system) during minimally invasive correction is the operation of choice for adolescent children with funnel chest deformities. The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of all participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: pectus excavatum; chest deformity; Nuss operation, surgery, pediatrics, thoracoplasty, results.

Chinook salmon rearing habitat–discharge relationships change as a result of morphodynamic processes

AbstractRelationships between fluvial aquatic habitat availability and discharge are often assumed to remain static when used with hydrologic datasets to analyze changes in habitat availability over time. Despite this assumption, studies have observed significant changes in aquatic habitat availability before and after restoration projects, dam removals, and extreme flood events. However, research is lacking on how aquatic habitat changes as a result of morphodynamic processes during more commonly occurring hydrologic conditions. This study compared Chinook salmon (Oncorhynchus tshawytscha) rearing habitat availability at 19 discharges before and after a relatively mild 8‐year hydrologic period punctuated with modest floods on the lower Yuba River in California, USA. During this time, the total area of rearing habitat remained relatively consistent at discharges &lt;2× bankfull but decreased by up to 25% at discharges &gt;2× bankfull. Significant decreases in rearing habitat area appeared to be the result of widespread erosion on floodplains, terraces, and lateral bars, even after only modest floods. As a result, spatially delineated areas of lost habitat tended to increase in water depth and velocity at baseflow, bankfull, and floodplain‐filling discharges, while areas of gained habitat decreased in depth and velocity. Although these specific results may not apply to all rivers around the world, the finding that habitat–discharge relationships change as a result of morphodynamic processes likely does transfer globally and should be considered when making long‐term regulatory and management decisions, such as instream flow requirements and habitat restoration plans.

Sinuous bar fingers of digitate shallow‐water deltas: Insights into their formative processes and deposits from integrating morphological and sedimentological studies with mathematical modelling

AbstractThis paper helps to address the growing need to resolve the severe loss of deltaic lands by providing a new understanding for shallow‐water digitate delta growth. The integration of satellite image analysis of modern deltas, field studies of the Ganjiang Delta in the Poyang Lake and ‘Delft3D’ simulations further results in improved facies models for shallow‐water digitate deltas. These analyses show that shallow‐water digitate delta bar fingers are sinuous in contrast to the straight deep‐water digitate delta bar fingers. These differences are assigned to the effect of water depth on outflow hydraulics, where friction‐dominated shallow‐water delta effluents promote mouth bar deposition that then divert flow around the mouth bar, resulting in the formation of sinuous bar fingers. These effects are further strengthened by the meandering of the shallow‐water jet that increases lateral sediment transport, and by the higher flow resistance and lower gradient of the shallow‐water outflows. Our data and analyses further show differences in the morphology and deposits of the shallow‐water sinuous bar fingers, where some bar fingers develop sinuous and others meandering (with point bars) distributary channels. Lateral channel migration and point bar formation (meandering) occur as a secondary process that does not change the shape or width of the bar fingers themselves, and is suggested to be a function of slight initial differences in channel sinuosity. These differences in distributary channel morphology have a strong effect on bar finger facies distribution. Sediment cohesion is another important control on bar finger bending processes, because high cohesion promotes formation of enclosed bays, where their bank strength exceeds the centrifugal force of water flow. Lower sediment cohesion results in sinuous bar fingers without formation of enclosed bays. This work provides insights into natural and artificial shallow‐water digitate delta growth and provides new quantitative facies models for shallow‐water digitate deltas.

The cratering performance of concrete target under true triaxial confinements

It is of great significance to evaluate the cratering performances of concrete target subjected to steel projectile impacting. Different from the method proposed by Forrestal et al. (2003) to record the acceleration signals in steel projectile by single-channel acceleration data recorder, a new testing equipment is established in the present study to record the dynamic triaxial responses of concrete target by six lateral bars. The projectile impacts the target through a hollow square bar (one of six lateral bars), and the true triaxial confinements are applied on the target through six lateral bars which loaded by three servo-controlled cylinders. These three forces, i.e. end resistance, lateral reaming resistance, and lateral traction, acted on the projectile toe during cratering process are discussed respectively by wave signal εy- recorded on the left bar in y-axial, by wave signals εx+, εx-, εz+, and εz- recorded on the lateral bars, and by specially assigned strain gauges demonstrated in Appendix B. Series of experiments of concrete targets under various impact velocities and under various confinements are conducted accordingly. Two stages, e.g. the accelerating cratering stage, and the decelerating cratering and penetration stage, are observed in stress σy- profiles. Similar lateral reaming stages are observed in stress profiles of lateral bars. These stress profiles could be used to evaluate forces applied on projectile toe, and lateral tractions could be ignored. Comparing with the cratering process in the impact direction, there are about 10µs delaying for the lateral reaming process. Depth of crater and pulse duration decrease with increasing confinements, and they exhibit obvious velocity and confinement dependency. Three dimensionless factors, i.e. the inertial effect, the strength effect, and the deformation characteristics, are introduced to evaluate the crater depth. Strength of concrete target is proven to be the most important factor in the cratering process for concrete target under lower impact velocity. This work provides comprehensive and profound understanding of the effects of multiaxial confinement on the crater resistance for concrete-like materials.