Hill Type Research Articles

Neuromonitoring Signal Changes in Degenerative Cervical Myelopathy: An Analysis of Risk Factors for Signal Drops During Posterior Cervical Decompression

To analyze intraoperative neuromonitoring data of patients with degenerative cervical myelopathy undergoing cervical laminectomy and assess the incidence of signal drops and their risk factors. This retrospective observational study included patients with degenerative cervical myelopathy who underwent cervical laminectomy with intraoperative neuromonitoring between July 2018 and March 2023. We analyzed the signal changes for any correlation with the type of pathology (ossified posterior longitudinal ligament vs. cervical spondylotic myelopathy [CSM]) and clinical (severity of myelopathy, duration of symptoms) and radiological (length of cord signal changes and K-line) parameters. Of 100 degenerative cervical myelopathy cases, 55 were diagnosed as OPLL and 45 as CSM. Signal drops were recorded in 26 patients-14 persistent drops and 12 transient drops. True positive drops were seen in 4 patients (2 OPLL and 2 CSM), 3 of whom had sustained bimodal drops (both somatosensory evoked potentials and motor evoked potentials). Signal drops were significantly more frequent with OPLL compared with CSM (P < 0.01). Ten of 14 persistent signal drops and 9 of 12 transient drops were seen in patients in OPLL. Continuous OPLL, negative K-line, hill type OPLL, severity of myelopathy, and longer duration of symptoms were risk factors for signal drops. Patients with cervical OPLL have a higher incidence of false positive and transient signal drops after decompression compared with patients with CSM. Longer duration of symptoms, high-grade myelopathy, continuous OPLL, hill type OPLL, and negative K-line were risk factors for signal drops.

Paleo-geomorphic features of pre-Jurassic and its oil-controlling effect in Wuqi–Dingbian area

The Fuxian-Yan10 layers are the main oil-producing reservoirs of Jurassic in Wuqi–Dingbian area of Ordos Basin. However, due to the lack of understanding of the pattern and distribution characteristics of oil reservoirs, the benefits of exploration and development are restricted. In order to provide theoretical guidance for the study of similar geological features, based on the analysis of paleogeomorphic features and evolution, the analysis focuses on the influence of palaeo-geomorphology on oil reservoir distribution, and summarizes the main types of reservoir models in the study area. The results show that there are four types of palaeo-geomorphic units in the Wuding area: palaeo-river, slope, highland and interriver hill. In the study area, the Jurassic paleogeomorphology controls the sedimentary development and distribution from Fuxian Formation to Yan 9 Formation. The compacted structure and lithologic barrier provide good trapping conditions for the paleogeomorphic oil. Moreover, the swampy coal measures and mudstone at the top of Yan 9 play a sealing role for oil accumulation, and the bottom water was obviously driven. In addition, the pre-Jurassic deep valley was the main channels for oil migration. On this basis, it is concluded that there are four reservoir-forming models in Wuding area: slope type, river hill type, ancient river type and highland type.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology.

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.

The turbulence models review for aerodynamic, thermal and structural problems in jet engine turbines

In the processes of their processing to obtain finished products, the internal structure and the properties of various scale levels of the material that depend on it change significantly, the prediction of which using empirical methods is extremely costly. For this reason, the development of processing technologies is unthinkable without mathematical models, the central element of which is constitutive relations. A promising approach for constructing the latter is the physical approach, which makes it possible to describe the evolution of the internal structure at various scale levels. As a rule, such models of materials are multilevel and represent a whole class of constitutive models. Of particular interest are elastoplastic models, since they allow calculations with sufficiently large time steps. Most models of this type are based on the Taylor - Bishop - Hill model. Models of this type have a drawback: uncertainty in the choice of a set of active slip systems. This uncertainty is due to the fact that the dislocation shear rates along slip systems are determined from a system of equations, the dimension of which may exceed the dimension of the space of independent variables being sought. In this paper, we study the influence of a random choice of sets of active slip systems in elastoplastic models of the Taylor - Bishop - Hill type on the results of mod-eling the elastoplastic deformation of polycrystals with a face-centered cubic lat-tice. The deviation in the simulation results was considered for a random choice of sets of active slip systems. For this purpose, special metrics were introduced to show the effect of uncertainty on the macrolevel stress tensor and misorientation angles between crystallites. It is shown that with increasing strains, a random choice of sets of active slip systems leads to an almost monotonous increase in differences in the calculation of the macrolevel stress tensor and misorientation angles between grains. This fact means that the problem of uncertainty in the choice of active slip systems inherent in these models affects the simulation re-sults. The indicated discrepancy between the simulation results evidences the need to develop an algorithm to eliminate the noted uncertainty, which is the sub-ject of the forthcoming publication of the authors.

Distribution of giant trees in the urban areas and western suburbs of Tokyo, Japan

ABSTRACT Giant trees reflect site environmental conditions and to elucidate the distribution pattern of the giant trees, we investigated relationships between giant tree locations and landforms. On the basis of elevation, the landforms of Tokyo were divided into four types (lowland, plateau, hill, and mountain), and tree distribution patterns were divided into five groups, including three sub-types, with occurrence patterns of representative species [I: Frequently lowlands, often plateaux and mountain type (Machilus thunbergi); II: Frequently plateaux, often lowland, hill, or mountain type (Quercus acuta, Prunus speciosa, Taxodium distichum, Liriodendron tulipifera, Cedrus deodara, Aphananthe aspera, and Prunus × yedoensis “Somei-yoshino”) with two subtypes, II-1: Typically plateaux (Cinnamomum camphora, Castanopsis sieboldii, and Ginkgo biloba) and II-2: Frequently plateaux and hills (Zelkova serrata); III: Typically plateaux and hill type (Certis sinensis var. japonica, Torreya nucifera, Carpinus tschonoskii, Quercus myrsinifolia, and Quercus serrata) with one subtype, Frequently plateaux (Prunus jamasakura); IV: Mountains often with plateaux or hill type (Acer pictum subsp. mono, Aesculus turbinate, Abies firma, Cryptomeria japonica, and Cercidiphyllum japonicum); and V: Mountain-limited type (Castanea crenata, Pterocarya rhoifolia, and Fraxinus platypoda)]. Some giant trees, including Quercus crispula, Fagus japonica, Fagus crenata, and Tsuga sieboldii, were distributed in mountainous areas but not on plateaux, hills, or in lowlands. Some unique giant trees (Aphananthe aspera, Certis sinensis var. japonica, and Carpinus tschonoskii) are self-seeding in the wild and found in plateau areas but not mountainous or hilly areas. These results suggest that the distribution of giant trees is influenced by site ecological characteristics, tree physiology, and human management and land-use.

ThTP2.14 Robot-assisted repair of paraoesophageal hernia: a systematic review

Abstract Aim Laparoscopic repair is quoted as the standard of care for paraoesophageal herniae but limitations include the 2D image, requirement of a trained camera assistant and surgeon fatigue. Robotic-assisted (RA) repair promises improved 3D visualization and ergonomics. However, there is limited data on short and long-term outcomes from RA repair. We aimed to systematically review literature on RA repair of paraoesophageal herniae and post-operative outcomes. Methods A systematic on-line literature search of Embase and Medline identified 200 articles of which 13 relevant studies were selected, including 7 retrospective and 6 prospective studies. Selected articles were assessed by two reviewers to extract relevant demographic and outcome data. Results 1601 patients received RA repair of paraoesophageal herniae with a median age of 62 years and 72% were female. The majority had Hill type 3 paraoesophageal herniae (80.5%). Predominately elective operations (86.4%) they had a mean operative time of 169.7 minutes, used mesh in 44.0% and included a fundoplication in 78.2%. Only one required open conversion. Median length of stay was 2.45 days (1.3-4.5 days). 15.4% had reported complications (dysphagia (9.7%), pneumothorax (0.4%), pneumonia (0.3%) post-operative haemorrhage (0.3%) and thrombosis (0.4%)). There were no post-operative mortalities. Few symptomatic recurrences were reported and there was a 1.8% re-operation rate within this cohort. Conclusion RA paraoesophageal hernia repair offers similar outcomes to those published in recent literature for laparoscopic repair, with potential for improved surgeon ergonomics and visualisation. Carefully designed, prospective trials comparing laparoscopic and robotic repair are required to further delineate the optimal surgical approach.

A classification of Broken Hill type deposits – A reply

A classification of Broken Hill type deposits – A reply

Division and identification of vertical reservoir units in Archaeozoic metamorphic buried hill of Bozhong Sag, Bohai Bay Basin, East China

Based on the data associated with cores, sidewall cores, casting thin sections, reservoir physical properties, conventional logging and imaging logging, the classification schemes of vertical reservoir units are proposed for the two types of Archaeozoic buried hills (exposed and covered ones) in the Bozhong Sag, Bohai Bay Basin. The geological characteristics and storage spaces of these reservoir units are described, and their identification markers in conventional and imaging log curves are established. The Archaeozoic metamorphic buried hills can be vertically classified into two primary reservoir units: weathering crust and inner buried hill. The weathering crust contains four secondary units, i.e., the clay zone, weathered glutenite zone, leached zone, disaggregation zone; and the interiors contain two secondary units, i.e., interior fracture zone and tight zone. In particular, the inner fracture zone was further divided into cataclasite belts and dense-fracture belts. It is proposed that the favorable reservoirs of exposed Archaeozoic metamorphic buried hills are mainly developed in four parts including weathered glutenite zone, leached zone, disintegration zone superposed with the cataclasite belt and the cataclasite belt of inner fracture zone, and are controlled by both weathering and tectonic actions. Favorable reservoirs in covered Archaeozoic metamorphic buried hills are mainly developed in the weathering crust superposed with the cataclasite belts and the cataclasite belts of inner fracture zone, and are mainly controlled by tectonic actions.

Application of Good Mining Practice at PT. Gunung Bale, Malang, East Java

This study aims to determine the application of Good Mining Practice at PT. Bale Mountain. Mining activities at Gunung Bale consist of processes: Stripping and Top Soil Management, Mining Production Operations, Stock Pile Activities, Quality Control and Transportation to Consumers. The methodology used is a study of the application of Good Mining Practice. Data and information are processed and tabulated for later analysis descriptively and quantitatively. The results showed that the Mining Technical PT. Gunung Bale uses the open pit mining method with a Quarry mining system with a site hill type and a pit type. Mineral conservation is carried out using the method of calculating the volume of resources and reserves with the Triangular method using the Block model concept (software used is SURPAC 6.6.1). To prevent work accidents at the mine site, warning signs are installed and Personal Protective Equipment (PPE) and first aid kits are provided. Every time starting mining activities, a safety talk is held with the workers. Environmental management includes waste management, restoration and monitoring of water quality, handling of acid mine drainage, revegetation, and making a reclamation plan. The main mining infrastructure for road construction cuts around ±2 Ha. The total length of the road is 2,731 m. Processing and refining facilities are not located in the mining area.

Numerical modelling of vibration response in loess hills due to a high-speed train on railway viaduct

In order to accurately analyze vibration characteristics and site effects of loess hills under moving load of a high-speed train, four types of loess hill models under railway viaduct was established by ABAQUS of finite element analysis software by field test. The dynamic response and stability of loess hills under two different vibration sources under high-speed train load were studied by using two-dimensional equivalent linear response time-history analysis, and the influence of the mechanical parameters of loess on the vibration of different types of loess hill was analyzed. Results show that there are obvious differences between peak displacement cloud maps of loess hills under the railway viaduct under gravity and train load action. We analyzed the influence of the change of elastic modulus on vibration propagation of soil of foundation and loess knoll, and found that the change of elastic modulus of soil in different position of foundation has more effect on vibration propagation than that of loess knoll soil. At the same time, the vertical acceleration cloud maps of the four types of loess hills are obviously different.

Impact of nonlinear infection rate on HIV/AIDS considering prevalence‐dependent awareness

An HIV/AIDS transmission model is constructed and analyzed that assimilates spontaneous change in human behavior depending on the disease prevalence incorporating self‐shielding mechanism and treatment control. It is assumed that human population become aware of HIV disease from exposed environment and are conscious enough to make their knowledge fruitful by adopting self‐protective measures to reduce disease transmission. We introduce Hill type of behavioral change function and an awareness‐induced transmission function associated with nonlinear infection rate. We emphasize the effectiveness of human awareness in controlling HIV epidemic by investigating the impact of nonlinear incidence rate. Further, an optimal control model is formulated and solved to find the strategy of applying treatment considering spontaneous response of people towards HIV disease. In the numerical simulation segment, impacts of significant parameters have been assessed using sophisticated techniques. We calibrate the proposed model with the real data of HIV cases in India and estimate some crucial model parameters. Moreover, different amalgamations of preventive and treatment controls are introduced. The optimal treatment control has massive impact in curbing HIV epidemic. Also, combined strategy of prevention and treatment can curtail the disease with economic gain. It reveals that effective response of individuals can suppress the disease in such an unexpected situation when treatment rate is low. Increasing the efficacy of human consciousness is much beneficial in curbing HIV outbreak. Thus, our findings highlight a path to control HIV epidemic with uninstructed modification of human behavior by boosting up the productivity of their existing knowledge.

Hill type muscle models do not capture the response to stretch in clinical tests of spasticity

Hill type muscle models do not capture the response to stretch in clinical tests of spasticity

Voids Filling of DEM with Multiattention Generative Adversarial Network Model

The digital elevation model (DEM) acquired through photogrammetry or LiDAR usually exposes voids due to phenomena such as instrumentation artifact, ground occlusion, etc. For this reason, this paper proposes a multiattention generative adversarial network model to fill the voids. In this model, a multiscale feature fusion generation network is proposed to initially fill the voids, and then a multiattention filling network is proposed to recover the detailed features of the terrain surrounding the void area, and the channel-spatial cropping attention mechanism module is proposed as an enhancement of the network. Spectral normalization is added to each convolution layer in the discriminator network. Finally, the training of the model by a combined loss function, including reconstruction loss and adversarial loss, is optimized. Three groups of experiments with four different types of terrains, hillsides, valleys, ridges and hills, are conducted for validation of the proposed model. The experimental results show that (1) the structural similarity surrounding terrestrial voids in the three types of terrains (i.e., hillside, valley, and ridge) can reach 80–90%, which implies that the DEM accuracy can be improved by at least 10% relative to the traditional interpolation methods (i.e., Kriging, IDW, and Spline), and can reach 57.4%, while other deep learning models (i.e., CE, GL and CR) only reach 43.2%, 17.1% and 11.4% in the hilly areas, respectively. Therefore, it can be concluded that the structural similarity surrounding the terrestrial voids filled using the model proposed in this paper can reach 60–90% upon the types of terrain, such as hillside, valley, ridge, and hill.

Cooking pasta with Lie groups

We extend the (gauged) Skyrme model to the case in which the global isospin group (which usually is taken to be SU(N)) is a generic compact connected Lie group G. We analyze the corresponding field equations in (3+1) dimensions from a group theory point of view. Several solutions can be constructed analytically and are determined by the embeddings of three dimensional simple Lie groups into G, in a generic irreducible representation. These solutions represent the so-called nuclear pasta state configurations of nuclear matter at low energy. We employ the Dynkin explicit classification of all three dimensional Lie subgroups of exceptional Lie group to classify all such solutions in the case G is an exceptional simple Lie group, and give all ingredients to construct them explicitly. As an example, we construct the explicit solutions for G=G2. We then extend our ansatz to include the minimal coupling of the Skyrme field to a U(1) gauge field. We extend the definition of the topological charge to this case and then concentrate our attention to the electromagnetic case. After imposing a “free force condition” on the gauge field, the complete set of coupled field equations corresponding to the gauged Skyrme model minimally coupled to an Abelian gauge field is reduced to just one linear ODE keeping alive the topological charge. We discuss the cases in which such ODE belongs to the (Whittaker-)Hill and Mathieu types.

Rediscovery and IUCN threat assessment of Themeda saxicola (Poaceae: Andropogoneae), an endemic grass from the Eastern Ghats, India

Themeda saxicola is an endemic perennial grass rediscovered after laps of 67 years from the Raisili hill (type locality) and Deomali hill, from the Eastern Ghats in the Koraput district of Odisha. The detailed description along with colour photographs of the habitats, habit and floral parts are provided for easy identification of the species. In addition, distribution map and IUCN threat category assessment are also provided.

Variational formulation of dynamical homogenization towards nonlocal effective media

The dynamical homogenization of heterogeneous materials is performed in the low and high frequency regimes using a variational formulation of dynamical equilibrium combined with the Laplace or Fourier-Floquet-Bloch decomposition of the mechanical fields (displacement, velocity, momentum, stress). The assumed periodicity of the initial heterogeneous structure entails that the homogenization process can be carried out at the scale of a reference unit cell over which periodicity conditions apply. A dynamical Hill type macrohomogeneity condition is formulated that plays a central role in this work. The weak form of the unit cell dynamical equilibrium is formulated as the minimization of the mean field action integral expressed versus the Floquet components of the displacement and velocity. The effective dynamical moduli are evaluated in reciprocal space as unit cell averages of the microscopic properties and localization operators relating the local velocity and strain to their macroscopic counterpart. More specific dynamical models involving locality in space (thus valid for long wavelengths) but nonlocality in time (thus describing both low and high frequency regimes) are formulated, considering Cauchy type and strain gradient effective models. The range of validity of the developed dynamical generalized continuum theories is assessed by comparing the phase velocity-wavenumber plots for inclusion based composites with reference plots obtained from Bloch's theorem. The benchmark of dynamical models evidences that the nonlocal dynamical model proves able to predict with a good accuracy the dynamical behavior of 2D periodic inclusion based composites.

Progress on Modeling of Dynamic Productivity of Fractured Gas Condensate Reservoir Based on a Fluid-Solid Coupling Method

Bozhong 19-6 gas field is the first discovered large-scale gas condensate field in eastern China, which is also one of the largest metamorphic rock gas condensate fields in the world. It is a buried hill type, low permeability reservoir, with ultra-high condensate content where the fluid is nearly at its dew point pressure. No similar experience with such reservoirs have previously been reported in the context of gas field development in China and step-by-step progresses is been made to characterize this reservoir. Overall, documentation concerning this type of reservoir is rarely seen worldwide. This paper includes key successful results from multiple perspectives including experiments correlations, numerical modeling and the significance of incorporating certain details. Based on a fluid-solid coupling method, the simulations consider several factors including the fracture distribution, low permeability, medium deformation, and condensate characteristics, as well as their effects on the gas productivity. In the laboratory experiments, the stress sensitivity of the rock was tested using representative core samples. Here, experiment-based correlations of the starting pressure gradient of the gas condensate reservoir are proposed. The starting pressure gradient of different fluid types, such as black oil and gas condensate are highlighted as accurately simulating the reservoir. As a result, the numerical model to predict the dynamic productivity of a single well was successfully established considering all those factors. This paper can serve as a reference for studying other studies of metamorphic, fractured gas condensate reservoirs.

Water Saturation Calculation and Fracture Type Identification of a Buried Hill Fractured Reservoir

Abstract A buried hill reservoir is a special type of bedrock reservoir, in which fractures are the important reservoir space and main percolation path. However, due to the characteristics of the buried hill reservoir such as deep burial depth and high formation pressure, the fracture width of deep formation is generally in micron level, and the randomness of spatial development brings great difficulties to logging identification and reservoir parameter calculation. Based on the fracture porosity and saturation model of the dual pore model, this paper puts forward the theory of identifying fracture type of buried hill fractured reservoir by using conductivity efficiency. The results show that (1) the fracture angle has no effect on the conductivity efficiency. And we cannot distinguish a high-angle fracture from a low-angle fracture by conductivity efficiency. (2) The values of porosity and water saturation are not directly related to the conductivity efficiency. But porosity and water saturation will affect the connectivity of water in the reservoir and indirectly affect the conductivity efficiency. (3) The conductivity efficiency of the network fracture is usually less than that of the dissolution fracture.

Effect of geometry and material of municipal solid waste landfills on seismic response

The stability of municipal solid waste (MSW) landfills is a significant environmental concern. The performance of landfills during earthquakes should be evaluated to ensure their stability. The geometry and material types of MSW landfills are the main factors affecting their seismic response. In this study, the individual and coupled impact of these factors is investigated using numerical analyses. Amplification factors (AFs = Accsurface/Accbase) are investigated for six common MSW landfill types, namely canyon type, hill type, side-hill types 1 and 2 and stepped-base types 1 and 2. The results show that landfill types have significantly different behaviours due to their geometry and waste material properties. For low stiffness contrasts, the stepped-base landfill type has the minimum and the hill type experiences the maximum AF, 1.74 and 3.53, respectively. However, for high stiffness contrasts, the canyon type has the minimum AF (0.46) due to the effect of damping and thickness of the waste. Therefore, the proper geometry of the MSW landfills should be designed for specific waste material properties according to the seismic response.

A Hill type equation can predict target gene expression driven by p53 pulsing.

Many factors determine target gene expression dynamics under p53 pulsing. In this study, I sought to determine the mechanism by which duration, frequency, binding affinity and maximal transcription rate affect the expression dynamics of target genes. Using an analytical method to solve a simple model, I found that the fold change of target gene expression increases relative to the number of p53 pulses, and the optimal frequency, 0.18 h−1, from two real p53 pulses drives the maximal fold change with a decay rate of 0.18 h−1. Moreover, p53 pulses may also lead to a higher fold change than sustained p53. Finally, I discovered that a Hill‐type equation, including these effect factors, can characterise target gene expression. The average error between the theoretical predictions and experiments was 23%. Collectively, this equation advances the understanding of transcription factor dynamics, where duration and frequency play a significant role in the fine regulation of target gene expression with higher binding affinity.