Decrease In Slope Research Articles

Experimental study on the morphology of turbulent diffusion flames with different aspect ratios under slope conditions

In this paper, the morphology of turbulent diffusion flames with varying aspect ratios under slope conditions was investigated. A simulated fire source using propane gas with an area of 80 cm2 was utilized. The influences of slope angle and aspect ratio of the fire source on the flame tilt angle (between the plume centerline and the slope), flame length, and flame height were systematically studied. The aspect ratio of the fire source (L/W) was changed from 1 to 8, and the slope angle was changed from 0° to 40°. Results indicate that the presence of a slope causes asymmetrical air entrainment on both sides of the fire plume, causing a pressure difference that leads to a decrease in the flame tilt angle as the slope angle increases. Additionally, the flame length increases monotonically with the slope angle due to the enhanced component of thermal buoyancy along the slope. Under the same slope condition, the flame tilt angle and flame height (perpendicular to the slope) decrease as the aspect ratio increases. This phenomenon is attributed to the increased entrainment restriction effect of the slope on the fire plume. New models for calculating flame tilt angle, flame length, and flame height, which consider the slope angle and aspect ratio of the fire source were established by using the equivalent perimeter of plume entrainment. To further verify the reliability of the newly established models, reference data with wide heat release rate (6.15 kW–231 kW), different slope inclination angle (0°–80°), pool size (equivalent diameter: 9 cm–44.1 cm), and different fuels (propane, ethylene) were used to against with the predicted values of our correlations. It is found that the maximum error of all correlations is within 15–20%, their universality and accuracy are further verified.

ANTHROPOGENIC TRANSFORMATION OF TERRAIN IN THE NORILSK INDUSTRIAL DISTRICT

The scale of anthropogenic terrain transformation within the Norilsk industrial region was quantified and a classification of its consequences has been elaborated. The work is based on the results of 2021 expeditionary geomorphologic studies, interpretation and analysis of remote sensing materials and digital elevation models. It has been established that the total area of direct terrain transformation during the territory development was about 122,4 km2, and that of indirect transformation - 23,6 km2. The volume of anthropogenic landforms is at least 1,8 billion m3; accumulative forms account for 93% of the area and 72,6% of the volume of direct landform transformations. The types of anthropogenic landforms were identified, it was found that the largest area is occupied by embankments for industrial development and tailings, and the largest volume is characteristic of slope dumps. Indirect terrain transformation is mainly activation of gravitational processes, linear erosion, suffusion, thermokarst, heaving and deflation. The mass displacement of slope dumps by landslides or stone glaciers are the most dangerous for infrastructure facilities. Separate areas of indirect transformations are mainly limited to the lacustrine-alluvial lowlands and the bottoms of river valleys. Among them, the largest area (up to 20 km2) is occupied by segments of river valleys affected by spills of oil products and tailings. It has been established that the accumulation of pollutants in river valleys of the Norilsk industrial region occurs within the internal deltas and ice glades where the longitudinal slope decreases. Three stages of anthropogenic development of the territory are distinguished (I - 1920-1953; II - 1953-1986; III - 1986-2021); the most significant increment in the area of anthropogenic terrain occurred from 1953 to 1986. The average rate of anthropogenic terrain area increment over the past 36 years amounted to 0,81 km2/year. The highest rates of area growth are characteristic of the Kayerkan and Talnakh regions, which is associated with ongoing mining.

The Use of Induction Sensors and Helmet-Based Shielding Technology to Identify Differences in Electromagnetic Fields in Patients With Cranial Neurological Disease Versus Healthy Controls.

Background and objective Electromagnetic fields (EMFs) stemming from neural circuits have been evaluated in healthy human subjects by using non-invasive induction sensor technologies with adjunctive shielding constrained to a helmet constructed of Mu-metal and copper mesh. These EMF measurements have been analyzed and discerned to alterphysiological states of movement, thoughts of movement, emotional thoughts, andplanned activities. However, these technologies have not yet been investigated as a diagnostic tool in patients with cranial neurological pathology to evaluate differences in patterns in the pathologic state compared to healthy controls. In light of this, we conducted this study to address this scarcity of data. Methods An observational study was conducted in which patients at a single center with cranial neurological disease of all causes were eligible to enroll; they had real-time non-invasive continuous EMF measurements obtained using induction sensors and a shielded helmet. These measurements were obtained in the resting state and then compared to previously obtained measurements in healthy volunteers. Post-processing analysis was conducted to evaluate the derivatives of these EMFs to identify changes in patterns. Results Fourteen patients with traumatic injury, stroke, and neoplasm with ages ranging from 14 to 81 years underwent successful analysis and post-processing of their cortically generated EMF waves. Patterns of EMF waves were compared topreviously obtained data from four healthy controls. It was identified that there was less variation in the EMF measurements in patients with neurological disease compared to healthy controls. This was identified based on differences in derivatives of the EMF waves anddecreased numbers of peaks and valleys in the EMF waves. Conclusions Novel induction sensors with an engineered, layered Mu-metal and copper mesh helmet for shielding with Mu-metal EMF channels appear to be efficient in measuring neural circuit-driven EMF non-invasively, in real-time, and continuously and can discern differences in EMF patterns between healthy volunteers and patients with neural circuit pathology. The decreased variability in EMF measurements in patients with neural pathology and greater decreases in slope within low-frequency measurements may be correlated with disrupted neural signaling from dysfunctional neurons and abnormalities in spatial and temporal summation. Some EMF changes inill individuals correspond to changes in the experimentally induced lesions in the animal model. Further studies are warranted to devise models of disease and healthy states to improve these technologies as a diagnostic modality.

Effect of Tillage Management and Soil Slope on Annual Soil Loss under Cereal Crops in Central India

The negative impacts of soil erosion on productivity are mainly attributed to the decline in soil fertility and water availability. Continuous tillage practices combined with removal of crop residue from the soil surface greatly increase the risk of soil erosion and nutrient depletion. Soil erosion creates many adverse impacts on the environment and soil health which influence the food security and the quality of life. In present study the effect of three tillage management (conventional tillage, ridge and furrow system and no tillage system) and soil slopes (1%, >1% to < 3%, >3 to <5% and >5%) on soil loss in twelve different soil series under cereal cropping in central India has been studied. The results of the study indicated that the tillage management plays an important role to reduce soil loss. No tillage system found showed minimum annual soil loss whereas the conventional tillage practice recorded the most. The soil loss found decreased with decrease in slope and vice-versa. The Bararia soil series found most vulnerable to the soil loss whereas the Dhodar soil series found resistant to soil loss across the slopes and tillage management practices studied under cereal cropping in central India.

Estimation of Soil Loss for Different Soil Series, Tillage Management and Slopes under Soybean Cropping in Malwa Agro-Climatic Zone

The soil erosion can cause a reduction in agricultural productivity, ecosystem disturbances, and pollution of water. Physical and climatic features of a catchment such as topographic conditions, land use land cover, rainfall intensity, and the soil characteristics are the key significant factors of the soil erosion. The loss of the top fertile soil nutrients is intensely increasing. In present study soil loss for 12 soil series viz., Kheri, Bararia, Junapania, Namali, Dhamaniya Diwan, Dhodar, Surajpura, Paroliya, Ratangarh, Khermaliya, Morwan and Hathipura and 3 different tillage management viz., conventional tillage, ridge and furrow system and no tillage system under soybean crop in Malwa Agro-climatic Zone in central India has been estimated. The soil loss for four different sloes viz., 1%, >1% to < 3%, >3 to <5% and >5% under these soil series and management practices have been studied. The results of the study revealed that soil loss found decreased with decrease in slope and vice-versa. Similarly, the soil loss was found higher under conventional tillage (4.134 t acre-1 y-1) as compared to the ridge and furrow system (1.447 t acre-1 y-1) and no tillage system (1.033 t acre-1 y-1). The Bararia soil series (4.196 t acre-1 y-1) found most vulnerable to the soil loss whereas the Dhodar soil series (1.036 t acre-1 y-1) was found resistant to soil loss under soybean cropping in Malwa Agro-climatic Zone.

Rational structural solutions for triangular trusses

Wooden rafter structures have undoubted advantages, which determine their wide application. The object of the study is triangular rafter structures. The purpose of the research is to find the dependence of force values in the elements of the studied structure on the magnitude of its lifting boom. The calculation of a triangular truss using the Maxwell - Cremona diagram is presented. The efficiency of the proposed method was estimated on the basis of a study of the structure of a wooden truss of the “scissors” type. The following pattern has been established: the change in the coordinates of the points (abscissas) of the force diagram is inversely proportional to the change in f . It is determined the area of rational values of the lift (roof slope) at which the values of internal forces tend to a minimum. It was revealed that the values of force increments in the truss elements at each step increase from 27% to 2 times when the roof slope de-creases. Based on the graphical analysis of the obtained data the range of effective values of the roof slope at which the forces in the elements of the truss take minimum values was found. Using a graphic method of determining the forces, it is possible to check variants of the roof slope in the search for a rational solution of the “scissor” type truss structure. It follows that the proposed method contributes to the choice of the most economical structural solutions.

Why studying the response of trait coordination to insularity matters?

AbstractFunctional island biogeography can provide eco–evolutionary insights into which main drivers contribute to shaping the distribution of organisms' forms and functions on islands. It does so by examining trait patterns. As a result, traits are increasingly studied on islands, either along insularity gradients or by comparing patterns of island versus mainland biota. So far, functional island biogeography has investigated trends of trait values (i.e., average, functional diversity), whereas coordination between pairs of traits remains unexplored along insularity gradients. Yet, trait coordination analyses constitute the foundational tool to detect main functional spectra and strategies of organisms. In this perspective, we set out to offer a conceptual and analytical framework that should facilitate the inclusion of trait coordination (i.e., the co–variation of traits both at the intra– and interspecific level) in functional island biogeography. We illustrate, with a case study focused on persistence traits of edaphic island plant specialists, what type of insights can be gained by examining the response of trait coordination to variation in insularity. We asked two questions, namely whether, with increasing insularity, the strength of the relationship (R2) increases (Q1), and the direction of the relationship (slope) decreases (Q2). We positively answered our research questions, with lines of evidence suggesting a selective “forcing” towards tighter and more strongly coordinated strategies (Q1), and functional trade‐offs (Q2). We infer which ecological and biogeographic drivers could be behind the observed patterns, while acknowledging possible drawbacks. We conclude by identifying three main take–home messages and related future directions for integrating trait coordination in functional island biogeography to further advance the field.

Go or grow? Feedbacks between moving slopes and shifting plants in high mountain environments

High mountains are climate change hotspots. Quickly rising temperatures trigger vegetation shifts such as upslope migration, possibly threatening mountain biodiversity. At the same time, mountain slopes are becoming increasingly unstable due to degrading permafrost and changing rain and snowfall regimes, which favour slope movements such as rockfall and debris flows. Slope movements can limit plant colonization, while, at the same time, plant colonization can stabilize moving slopes. Thus, we here propose that response of high mountain environments to climate change depends on a ‘biogeomorphic balance’ between slope movement intensity and the trait-dependent ability of mountain plants to survive and stabilize slopes. We envision three possible scenarios of biogeomorphic balance: (1) Intensifying slope movements limit vegetation shifts and thus amplify instability. (2) Shifting ecosystem engineer species reduce slope movement and facilitate shifts for less movement-adapted species. (3) Trees and tall shrubs shifting on stable slopes limit slope instability but decrease biodiversity. Previous geomorphic, ecological and palaeoecological studies support all three scenarios. Given differences in ecologic and geomorphic response rates to climate change, as well as high environmental heterogeneity and elevational gradients in mountain environments, we posit that future biogeomorphic balances will be variable and heterogeneous in time and space. To further unravel future biogeomorphic balances, we propose three new research directions for joint research of mountain geomorphologists and ecologists, using advancing field measurement, remote sensing and modelling techniques. Recognizing high mountains as ‘biogeomorphic ecosystems’ will help to better safeguard mountain infrastructure, lives and livelihoods of millions of people around the world.

Characterization and Analysis of Landslide Evolution in Intramountain Areas in Loja (Ecuador) Using RPAS Photogrammetric Products

This case study focuses on the area of El Plateado near the city of Loja, Ecuador, where landslides with a high impact on infrastructures require monitoring and control. The main objectives of this work are the characterization of the landslide and the monitoring of its kinematics. Four flights were conducted using a remotely piloted aerial vehicle (RPAS) to capture aerial images that were processed with SfM techniques to generate digital elevation models (DEMs) and orthoimages of high resolution (0.05 m) and sufficient accuracy (below 0.05 m) for subsequent analyses. Thus, the DEM of differences (DoD) and profiles are obtained, but a morphometric analysis is conducted to quantitatively characterize the landslide’s elements and study its evolution. Parameters such as slope, aspect, topographic position index (TPI), terrain roughness index (TRI), and topographic wetness index (TWI) are analyzed. The results show a higher slope and roughness for scarps compared to stable areas and other elements. From TPI, slope break lines have been extracted, which allow the identification of landslide features such as scarps and toe tip. The landslide shows important changes in the landslide body surface, the retraction of the main scarp, and advances of the foot. A general decrease in average slope and TRI and an increase in TWI are also observed due to the landslide evolution and stabilization. The presence of fissures and the infiltration of rainfall water in the unsaturated soil layers, which consist of high-plasticity clays and silts, contribute to the instability. Thus, the study provides insights into the measurement accuracy, identification and characterization of landslide elements, morphometric analysis, landslide evolution, and the relationship with geotechnical factors that contribute to a better understanding of landslides. A higher frequency of the RPAS surveys and quality of geotechnical and meteorological data are required to improve the instability analysis together with a major automation of the GIS procedures.

Bearing capacity of strip footing on c-ϕ slope under rainfall condition

This paper presents a novel solution for predicting the bearing capacity of a strip footing on a c-ϕ (cohesive-frictional) slope under rainfall conditions. The commercial finite element PLAXIS code was adopted for numerical modelling purposes. The bearing capacity of the strip footing is expressed through a dimensionless bearing capacity factor. The bearing capacity was examined considering the rainfall conditions and variation of design parameters, e.g., soil strength parameters, slope angle, and setback ratio. The results show that the bearing capacity of strip footing on the slope decrease under rainfall compares to its normal condition and the effects of each parameter on the UBC. The paper’s results can be a helpful reference for practical engineering in predicting the bearing capacity of strip footing on the c-ϕ slope under rainfall conditions.

Suprathreshold length summation.

To investigate the mechanisms underlying elongated spatial summation with a pattern-masking paradigm, we measured the contrast detection thresholds for elongated Gabor targets situated at 3° eccentricity to either the left or right of the fixation and elongated along an arc of the same radius to access homogeneous retinal sensitivity. The mask was a ring with a Gabor envelope of the same 3° center radius containing either a concentric (iso-orientation mask) or a radial (orthogonal mask) modulation. The task of the observer was to indicate whether the target in each trial was on the left or the right of the fixation. With orthogonal or low contrast iso-orientation masks, target thresholds first decreased with size with slope -1 on log-log coordinates until the target length reached 45' (specified as the half-height full-width of the Gabor envelope) and then further decreased according to a slope of -1/2, the latter being the signature of an ideal summation process. When the contrast of the iso-orientation mask was sufficiently high, however, the target thresholds, while still showing a -1 slope up to ∼10', asymptoted up to about 50' length, suggesting that the presence of the mask eliminated the ideal summation regime. Beyond about 50', the data approximated another -1 slope decrease in threshold, suggesting the existence of an extra-long channel that is not revealed by the conventional spatial summation paradigm. The full results could be explained by a divisive inhibition model, in which second-order filters sum responses across local oriented channels, combined with a single extra-long filter at least 300' in extent. In this model, the local filter response is given by the linear excitation of the local channels raised to a power, and scaled by divisive inhibition from all channels in the neighborhood. With the high-contrast iso-orientation masks, such divisive inhibition swamps the response to eliminate the ideal summation regime until the stimulus is long enough to activate the extra-long filter.

Cyclic bond behavior in reinforced concrete flexural members exposed to elevated temperatures

After enduring fire incidents, many reinforced concrete (RC) structures require assessment of their ability to withstand future seismic loads. A critical factor contributing to seismic behavior of such structures is residual bond between steel and concrete under cyclic loading. This paper examines cyclic bond-slip behavior in RC flexural members that have experienced elevated temperatures. Twenty-six modified beam-end specimens with different diameters of longitudinal reinforcement, concrete strengths, and confinement levels were fabricated. The specimens were subjected to a variety of heating regimes and a natural cool down before loading of their longitudinal rebar in a monotonic or cyclic pattern. The decrease in bond strength after 2-hr exposure to temperatures of 400, 600, and 700 °C were 23, 58, and 65 percent for monotonic loading but 30, 60, and 65 percent for cyclic loading, respectively. Elevated temperatures also caused a decrease in slope and area of hysteretic bond-slip loops. Cyclic bond strength was 25–45% less than monotonic bond strength and better correlated with the residual compressive strength of concrete, unlike monotonic bond strength, which was better correlated with the square root of this property. A model was proposed for backbone bond-slip curves of RC flexural members that are exposed to elevated temperatures.

#4204 MULTIPARAMETRIC MAGNETIC RESONANCE IMAGING BIOMARKERS OUTPERFORM LAB BIOMARKERS FOR PREDICTING PROGRESSION OF DIABETIC KIDNEY DISEASE

Abstract Background and Aims We recently showed that comprehensive non-contrast multiparametric Magnetic Resonance Imaging (mpMRI) allowed functional and structural assessment of diabetic kidney disease (DKD) and that an imaging endpoint, R1 cortex, showed significant predictive property for progression of DKD. We further investigated the performance of other MRI and lab biomarkers for predicting disease progression. Method In this prospective study, 38 DKD subjects aged 18–79 years and 20 age- and gender-matched healthy volunteers (HV) were included at baseline. 31 DKD subjects (2 stage 2, 13 stage 3, 14 stage 4, and 2 stage 5) and 17 HV were re-examined at 2 years ± 6 months. Clinical and lab examination, iohexol clearance for measured glomerular filtration rate (mGFR), urine albumin:creatinine ratio (UACR) and mpMRI were performed at both visits. A wide range of MRI biomarkers associated with kidney hemodynamics, oxygenation and macro/microstructure were included for evaluation. Disease progression was defined by at least one of the following at 2 years: decrease in mGFR slope of >5 mL/year/1.73 m2; worsening UACR category; or any major adverse kidney event defined as sustained decrease in eGFR of >40%; doubling of serum creatinine from baseline; development of kidney failure with mGFR <15 ml/min/1.73 m2; or death from renal cause. Univariable logistic regression analyses were performed to discriminate between progressors and non-progressors using each relevant lab and imaging endpoint as a predictor variable. Results Mean 2-year mGFR decline (ml/min/1.73 m2) in DKD patients was -2.7± 5.4 and in HV -1.9 ± 10.7. 13/31 (42%) DKD subjects and 4/17 (24%) HV progressed. Key lab biomarkers are shown in Table 1 and MRI biomarkers in Table 2. Conclusion Of all analyzed biomarkers, only the imaging biomarker R1 cortex, which reflects molecular environment viscosity, fibrosis, and inflammation (interstitial oedema, cellular swelling) showed significant predictive property for progression of DKD. UACR trended towards significance but was not statistically significant. R1 cortex outperformed all other imaging and lab biomarkers, but further studies with R1 cortex as a pre-specified endpoint are required to confirm these results.

Dynamic Changes in Agroecosystem Landscape Patterns and Their Driving Mechanisms in Karst Mountainous Areas of Southwest China: The Case of Central Guizhou

Puding County in central Guizhou is a typical karst ecologically vulnerable area integrating rural, mountainous, and ecological migration areas. It is essential to study the dynamic trajectory and direction of its agroecosystems (AESs) transformation to promote sustainable land use development in karst mountain areas. Based on high-resolution remote sensing images from 2004 to 2020, this study analyzes the transformation characteristics, typical landscape patterns, and their driving forces of AESs using the landscape pattern index, moving window method, and Geodetector model. The results show that: (i) The overall landscape pattern of AESs in the study area developed towards complexity and diversification from 2004 to 2020. The overall trend of woodland and grassland (WGL) is increasing, the slope cultivated land (SCL) is shrinking, the construction land (CL) is spreading and expanding along the vicinity of the town, and the economic and fruit forests (EFF) are increasing significantly. (ii) Three typical patterns are concluded according to the main transformation directions of AESs: WGL restoration type, CL growth type, and EFF growth type; middle and high mountains are dominated by the WGL restoration type with increased ecological functions, and the concentration of the new WGL increases with the increase in elevation; low mountain areas are dominated by the CL growth type with enhanced living functions, and the concentration of the new CL decreases with the increase in slope and elevation; valleys and hills are dominated by the EFF growth type with enhanced ecological and economic functions, and the concentration of the new EFF increases with the decrease in slope and elevation. (iii) Socio-economic factors are the dominant drivers of AES transformation. The WGL restoration type is dominated by slope and elevation, the CL growth type is mainly influenced by slope and urbanization rate, and the EFF growth type is primarily influenced by soil organic matter, slope, urbanization rate, and resident population. The study results have implications for rural land use, rural development, and ecological restoration of rocky desertification in karst mountain areas and other similar mountainous areas.

ARTERIAL BAROREFLEX FUNCTION IS IMPAIRED DURING THE RECOVERY FROM ACUTE LUNG INJURY IN A BLEOMYCIN-INDUCED RAT LUNG INJURY MODEL

Objective: Acute lung injury (ALI) and its clinical correlate, the acute respiratory distress syndrome (ARDS), results due, in part, to disruption of the normal capillary endothelial barrier and invokes perturbations of ventilatory control. ALI is associated with autonomic dysfunction and cardiac arrhythmias. In a recent study we suggested that rats were susceptible to cardiac arrhythmia even during the recovery from ALI, in part, due to abnormalities in cardiac sympathetic ganglia. On the other hand, if arterial baroreflex function is altered during the recovery of ALI remains unknown. The primary goal of this study was to examine baroreflex function during the recovery stage from ALI in a bleomycin (Bleo)-induced rat ALI model. Design and method: ALI was induced in male SD rats (200-250g) using a single intra-tracheal injection of Bleo (2.5 mg/kg). 4 weeks post Bleo (n = 7) or saline (sham, n = 6), rats were anesthetized with urethane (800 mg/kg ip) and alpha-chloralose (40 mg/kg ip) to measure baroreflex sensitivity. Baroreflex curves were generated by measuring the heart rate (HR) and renal sympathetic nerve activity (RSNA) responses to decreases and increases in mean blood pressure (MAP) by intravenous administration of nitroglycerin (25 μg) followed by phenylephrine (10 μg). Differences between sham and Bleo rats were determined by one-way ANOVA followed by the Tukey post hoc test. Results: Compared to sham rats, there was a significant decrease in the RSNA (117.4±11.6 vs. 77.5±8.9 %baseline, P = 0.018) or HR (147.5±9.7 vs. 75.1±11.3 bpm, P<0.001) range in Bleo rats. Minimum RSNA or HR was also decreased in bleo rats compared to sham rats. There was no significant difference in either the slope coefficient or the blood pressure at the midpoint of the range (BP50) between the two groups. There was a significant decrease in peak slope [or maximum gain (Gainmax) in Bleo rats (MAP-RSNA Gainmax: 3.11±0.27 vs. 1.74±0.31, p = 0.017; MAP-HR Gainmax: 3.57±0.31 vs. 1.21±0.14, p<0.001). Conclusions: Our data demonstrate impaired baroreflex function during the recovery state from ALI. Autonomic dysfunction may also contribute to increased cardiovascular risk during the recovery stage from ALI.

Arthrofibrosis in Robotic Total Knee Arthroplasty: An Investigation Into How Robotic Assistance May Contribute to a Tight Knee

Arthrofibrosis after total knee arthroplasty (TKA) can lead to pain and restricted range of motion. Matching native knee kinematics is crucial in avoiding arthrofibrosis postoperatively. However, manual jig-based instruments have demonstrated variability and inaccuracy during primary TKA. Robotic-arm-assisted surgery was developed to increase the precision and accuracy of bone cuts and component alignment. In the literature, limited information on arthrofibrosis after robotic-assisted TKA (RATKA) exists. The purpose of this study was to compare the incidence of arthrofibrosis after manual TKA (mTKA) with RATKA by examining the need for manipulation under anesthesia (MUA) postoperatively and evaluating preoperative and postoperative radiographic parameters. A retrospective analysis of patients who underwent primary TKA from 2019 to 2021 was conducted. Rates of MUA were evaluated and perioperative radiographs were analyzed to determine posterior condylar offset ratio, Insall-Salvati Index, and posterior tibial slope (PTS) in patients who underwent mTKA versus RATKA. Range of motion was recorded for patients who required MUA. A total of 1234 patients were included, of which 644 underwent mTKA, and 590 underwent RATKA. Thirty-seven RATKA patients compared with 12 mTKA patients required MUA postoperatively (P < 0.0001). A significant decrease in PTS postoperatively was seen in the RATKA (7.10° ± 2.4° preoperatively versus 2.46° ± 1.2° postoperatively), with a mean decrease of the tibial slope of -4.6° ± 2.5° (P < 0.0001). In patients requiring MUA, a larger decrease was seen in the RATKA group when compared with the mTKA group (mean -5.5 ± 2.0 versus -5.3 ± 0.78, P = 0.6585). No significant difference was seen in the posterior condylar offset ratio and Insall-Salvati Index in both groups. When conducting RATKA, it is important to match PTS close to the native tibial slope to decrease the incidence of arthrofibrosis postoperatively, as a decrease in PTS can lead to decreased postoperative knee flexion and poor functional outcomes.

Influence of bimetal interface confinement on the Hall-petch slope of multiscale Cu/Nb multilayer composites

Heterostructured materials afford a new way to improve the mechanical properties, which has become vital in both materials science and engineering applications. In the present research, Cu/Nb multilayer composites with layer thicknesses from the micrometer to nanometer were fabricated by accumulative roll bonding and the microstructure and mechanical properties of the Cu/Nb multilayer composites were then investigated. The yield strength and ultimate tensile strength of these composites increase with decreasing layer thickness. Moreover, the relationship between yield strength and (layer thickness)−1/2 approximately accords with the conventional Hall-Petch equation but with a decrease in the Hall-Petch slope when the layer thickness decreases from the micrometer to nanometer scales. The deformation microstructure of these Cu/Nb multilayer composites clearly exhibit dislocations glide in the layers, which reduces the stacking of dislocations at the Cu–Nb interface and thereby weakens the strengthening effect of the interface.

Ecogeomorphic interactions of Russian olives (Elaeagnus angustifolia) and point‐bar morphology along Powder River, Montana, USA

AbstractPoint bars are crucial alluvial features that help sustain meandering river ecosystems. They are influenced by interactions among physical processes and biological components, such as riparian vegetation. Understanding the mechanisms underlying these interactions can inform management decisions. The meandering Powder River in southeastern Montana, USA, provides a valuable study system for fluvial interactions because it has no major human alterations. Riparian stands of non‐native Russian olive trees (Elaeagnus angustifolia) became noticeable after ~50‐year flood in 1978. Fortuitously, 20 channel cross‐sections had been established in 1975 and 1977 and have been surveyed periodically ever since. This temporally extensive dataset was coupled with a spatially extensive dataset of 85 point‐bar cross‐sections derived from high‐resolution LiDAR that enabled evaluation of interactions between Russian olives and point‐bar morphology through time and space. Based on published literature and field observations, we hypothesised that an increase in the width of Russian olive stands would result in (1) a decrease in the overall point‐bar slope, (2) an increase in point‐bar heights and (3) in point‐bar toe‐slopes. The results indicated that point‐bar slopes did decrease with an increase in stand width, supporting the first hypothesis (R2 = 0.87). However, point‐bar heights decreased with an increase in stand width (R2 = 0.63), contradicting the second hypothesis and there was no relation between point‐bar toe‐slopes and stand width (R2 &lt; 0.1). The reverse hypothesis that point‐bar morphology controls Russian olive stand widths makes more biophysical sense. Thus, Russian olive stand width increases as the point‐bar slope and height decrease (R2 = 0.79 and 0.50), which provide a greater area of inundation for colonisation. This study demonstrates that geomorphology is controlling non‐native vegetation colonisation along Powder River, but that the subsequent stabilisation associated with Russian oliveexpansion may in turn upset the critical geomorphic balance between bank erosion and point‐bar aggradation necessary for a stable meandering system.

Stability analysis of nonhomogeneous and anisotropic stepped slopes under the influence of earthquakes

There have been many studies related to the stability of single-step slopes, but there have been few studies on the stability of stepped slopes. Based on the limit analysis method and the strength reduction method, the stability factor FS of a stepped slope in nonhomogeneous and anisotropic soils is calculated. Then, the calculation method in this paper is compared with previous studies to verify the correctness of the calculation method. Finally, the parametric analysis of the stepped slope is also carried out. The results show that the maximum error obtained by the calculation method of this paper does not exceed 5%, which verifies the rationality and effectiveness of the method in this paper. The ratio B/H of slope width to slope height significantly affects the stability of the slope. When B/H < 3, FS decreases sharply with increasing B/H; when B/H > 3, FS decreases slowly with increasing B/H. When the inclined angle, anisotropy parameter and seismic parameter of the slope increase, the stability of the stepped slope decreases; when the platform width parameter and soil nonhomogeneity parameter of the slope increase, the slope stability is also improved.

Effect of Posterior Tibial Slopes on Graft Survival Rates at 10 Years After Primary Single-Bundle Posterior Cruciate Ligament Reconstruction

Background: Recent biomechanical studies have reported that stress on the posterior cruciate ligament (PCL) graft increases as the posterior tibial slope (PTS) decreases (flattened) in knees with single-bundle (SB) and double-bundle PCL reconstruction. Clinical studies of SB PCL reconstruction have shown that a flattened PTS is associated with a lesser reduction in posterior tibial translation. There is no long-term study on the clinical outcomes and graft survival rates of SB PCL reconstruction based on the medial and lateral PTSs measured on magnetic resonance imaging. Hypothesis: Flattened medial and lateral PTSs are associated with poor clinical outcomes and graft survival rates at a minimum 10-year follow-up after SB PCL reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: In this cohort study, we retrospectively reviewed 46 patients (mean age, 28.8 ± 9.9 years) who underwent primary SB PCL reconstruction between 2000 and 2009. They were followed up for a minimum of 10 years. The medial and lateral PTSs were measured on preoperative magnetic resonance imaging. As a previous study reported that a steeper medial or lateral PTS showed a higher risk of anterior tibial translation at thresholds of 5.6° and 3.8°, respectively, the patients were divided into 2 groups based on the cutoff values of both the medial (≤5.6° vs >5.6°) and lateral (≤3.8° vs >3.8°) PTSs. Clinical scores (International Knee Documentation Committee subjective score, Lysholm score, and Tegner activity score), radiological outcomes (side-to-side difference [SSD] on stress radiography and osteoarthritis progression), and graft survival rates were compared between the groups at the last follow-up. Results: All clinical scores and the progression of osteoarthritis demonstrated no significant difference between the 2 subgroups of both the medial and lateral PTS groups. The mean SSD on stress radiography after SB PCL reconstruction was significantly greater in patients with a medial PTS ≤5.6° than in patients with a medial PTS >5.6° (8.4 ± 3.9 vs 5.1 ± 2.9 mm, respectively; P = .030), while the lateral PTS subgroups after SB PCL reconstruction demonstrated no significant difference. The minimum 10-year graft survival rate was significantly lower in patients with a medial PTS ≤5.6° (68.4% vs 92.6%, respectively; P = .029) and a lateral PTS ≤3.8° (50.0% vs 91.7%, respectively; P = .001). Conclusion: A flattened medial PTS (≤5.6°) was associated with an increased SSD on stress radiography, and both flattened medial (≤5.6°) and lateral (≤3.8°) PTSs resulted in lower graft survival rates at a minimum 10-year follow-up after primary SB PCL reconstruction.