We review the general properties of optical reflection spectra recorded from smooth solid surfaces from the infrared up to the X-ray spectral regions. Emphasis is placed on metal surfaces. By introducing a parallelism between a simple classical oscillator model treatment and surface reflection of light, general features of normal incidence reflection spectra are derived in a qualitative manner. This rather tutorial approach as relevant for an ideal metal surface is complemented by a broad elaboration of analytical features of realistic reflection spectra. The discussed topics include manageable dispersion formulas, the Kramers–Kronig method, oblique light incidence effects with an emphasis on Azzam’s analytical relations between the Fresnel’s coefficients, as well as special spectroscopic configurations involving reflection measurements at grazing light incidence. Further emphasis is placed on Infrared Reflection Absorption Spectroscopy IRAS, the Berreman effect, as well as X-ray reflectometry XRR. This way, we provide a synthesis of basic textbook material with advanced experimental and theoretical skills useful in the analytical work of an optical coating practitioner.

We have investigated the fundamental properties of obliquely propagating dust-ion-acoustic shock waves in a collisionless, viscous, magnetized plasma medium comprising Maxwellian distributed hot protons, hot electrons and cold electrons, inertial ions, and immobile negatively charged dust species. A set of fluid equations is considered to describe our plasma system and then reduced to a partial differential equation so called Burger’s equation, with the help of the reductive perturbation method. Under the suitable boundary conditions, Burger’s equation gives the shock wave solution. It is seen that basic properties (viz. speed, amplitude, width, etc.) of dust-ion-acoustic shock waves are significantly changed with plasma parameters. It is observed that our plasma system under consideration supports only positive shock structures. The dissipation coefficient is influenced by the effect of viscosity. The effect of obliqueness of the external magnetic field arises in the nonlinear coefficient. The implications of our theoretical investigation of shock wave formation in both laboratory and space plasmas under the influence of an external magnetic field are briefly discussed.

ABSTRACT Understanding the spatial distribution of wave overtopping behind coastal protection structures is critical for an accurate safety assessment of the protected regions. This paper presents a systematic review of the current state of research in this field, summarizing the key mechanisms and predictive methodologies. While physical modeling has traditionally been the primary method for investigating spatial overtopping, its outcomes are often simplified into empirical formulas. However, their predictive accuracy of these formulas is compromised when applied to diverse structural geometries, a limitation stemming from their calibration against a narrow range of configurations. To address this limitation, this study proposes a novel semi-analytical model that, by refining the calculation of overtopping velocity at the structure’s crest, achieves a more accurate prediction of the spatial distribution of overtopping on coastal structures with diverse slopes. The model results show good agreement with numerical simulations and multiple sets of experimental data. Additionally, researchers still face challenges in addressing uncertainties from scale effects, quantifying wind effects in laboratory settings and translating them into practical guidance, predicting overtopping distribution under extreme climatic conditions, and assessing the effects of oblique waves and 3D effects on the spatial distribution of overtopping.

Effect of Anatomic Joint-Line Obliquity Prostheses on Coronal Plane Alignment of the Knee Alignment in a Chinese Population

Abstract The Earth's glacial cycles are influenced by variations in its orbital parameters, particularly obliquity, precession, and eccentricity. These variations alter solar radiation distribution, impacting climate dynamics and sea ice formation. The effects of obliquity and eccentricity‐modulated precession on sea ice area and thickness are analyzed using climate model output from a series of idealized single‐forcing experiments from the Geophysical Fluid Dynamics Laboratory CM2.1 and the National Center for Atmospheric Research Community Earth System Model version 1.2. Results indicate that obliquity, under preindustrial precession conditions, exerts a stronger influence on annual sea ice variations than precession, under preindustrial obliquity conditions, in both the northern and southern hemispheres, primarily due to its effect on annual mean insolation. Precession, while still impactful, induces seasonal anomalies that tend to counteract one another, reducing its overall contribution. These findings highlight the significant role of obliquity in regulating sea ice over glacial timescales.

Abstract In this article, we study the conditions required to maintain a stable ocean on Mars 3 Ga using a new suite of simulations. These simulations couple a 3D Global Climate Model with ocean dynamics and ice sheet flow. The model includes the main processes of the atmosphere/hydrosphere/cryosphere to investigate Mars' ancient climate. The results show that the total water content required to maintain an ocean is m, global equivalent layer, half in the ocean, half in the ice sheet. This number seems plausible if a significant amount of water has been absorbed by the ground. This could be in the form of mineral alteration, or in a deep porous reservoir. In addition, the results show that the equilibrium mass flux from the ice sheet adjacent to the northern ocean is kg/y with a very low sliding velocity (1 m/y), except for few warm regions in the lowest altitudes that could reach up to 300 m/y. Finally, the global atmosphere/hydrosphere/cryosphere equilibrium should be reached in a few 100 ky. This indicates that the ocean will have a stabilizing feedback on timescales longer than this. An extensive sensitivity study of the ice sheet was performed. This included the effects of a geothermal heat flux, viscosity and basal drag. Finally, we studied the possible effects of planetary obliquity and a reduced ocean extent.

This study was inspired by the synergistic effects of various bionic design strategies and innovatively proposed a bionic gradient hierarchical asymmetric fractal structure design method that combines micro-level and macro-level biological structural characteristics. This method was then applied to the development of a novel bionic bi-gradient hierarchical asymmetric fractal bi-hexagonal tube (ABGBT-H) structure. Through numerical simulation methods, using aluminum alloy AA6061-O as the research object, this study focuses on investigating the influence of the configuration elements of the ABGBT-H structure on its dynamic compression behavior and energy absorption characteristics under oblique load angle conditions. The research results indicate that the ratio of inner and outer tube diameters (R-value) has a significant impact on the crashworthiness of the four ABGBT-H structures, and the appropriate R-value should be selected based on specific performance requirements in practical applications. The specific energy absorption (SEA) values of all structures exhibit a clear negative correlation with increasing load angle. Among them, the ABGBT-H33 structure demonstrates superior crashworthiness under oblique load conditions.Compared with other typical high-crashworthiness structures, the ABGBT-H33 structure with appropriate design parameters has obvious advantages over other structures in terms of SEA. However, this study only focused on AA6061-O aluminum alloy material and made assumptions such as material isotropy, structural uniformity, idealized collision processes, and simplified boundary conditions, which cannot fully reflect the actual performance of different materials in similar research scenarios. However, comparing the simulation results of the finite element model based on these assumptions and modifications with experimental results shows that the error is within an acceptable range, thereby validating the accuracy of the model. Future research could consider expanding the range of materials and optimizing the assumptions to further enhance the generalizability and accuracy of the results. Overall, these studies provide effective guidance for the development of lightweight, high-performance crashworthiness structures.

ObjectiveBackward walking may promote the preferential recruitment of lumbar extensors to optimize flexed spinal posture adopted LBP flexion subgroup. This cross-sectional study investigated the backward-walking exercise on a) real-time muscle activation, and b) its immediate effect on back pain intensity, movement control and lumbopelvic muscle activation in individuals with chronic non-specific LBP characterized with lumbar flexion syndrome.MethodThirty adults with chronic non-specific LBP with clinical manifestation of flexion syndrome received assessments of their movement control at static standing and during the five-minute forward walking test, conducted before and after a 15-minute treadmill walking training in forward or backward direction (as the immediate effect), while real-time adaptation of the lumbopelvic muscles during walking training was also evaluated. Comparisons of back pain intensity, ratio of the normalized electromyography (EMG) of the paired lumbopelvic muscles during walking, and performance of the lumbar movement control tests (LMC) using inferential statistics to analyze between- and within-subject effects differences for the a) real-time and b) immediate effects of the single session of walking training designated in a backward direction as compared to forward direction.ResultsTwo-way repeated measures analysis of covariance (ANCOVA) was adopted to minimize the confounding effect from covariates identified (maximal tolerable gait speed for EMG amplitude analysis, and gender for pain intensity and performance in lumbar movement control (LMC) tests). Significant post-training improvement in pain intensity (p = 0.014) and overall performance of the LMC tests (p = 0.006) were found for those who received backward walking training. Significant overall between-group effect (p = 0.022–0.026) and time-and-group interaction effect (p = 0.004–0.022) of ipsilateral internal oblique (IO) to multifidus (MF) ratio were found in swing phases of both legs. For ipsilateral erector spinae (ES) to rectus abdominis (RA) ratio, significant time effect (p = 0.022), between-group differences (p = 0.031), and real-time reduction during forward walking in left swing phase, and significant between-group differences (p = 0.024), time-and-group interaction effect (p = 0.009), and real-time increase during backward walking in right swing phase were noted. Real-time increasing trend during backward walking and real time decreasing trend of ipsilateral MF to ES ratio during forward walking were observed in stance phase of both legs, with time-and-group interaction effect at 6th (p = 0.007) and 12th minute (p = 0.006) during walking training in left stance phase.ConclusionsBackward walking exercise emerges to benefit LBP patients with lumbar flexion syndrome by inducing real-time increase in back extensors and deep stabilizing muscle recruitment together with the immediate post-training improvement in pain intensity and LMC test performance. Further research with longer training duration and larger sample size are recommended to better understand if greater and more sustainable therapeutic effect can be achieved with the walking exercise in backward direction for this specified LBP subgroup.

Laminar-to-turbulent transition in shear flow can be complicated and may follow many possible routes. The scenario based on the soliton-like coherent structure (SCS) [Lee and Wu, “Transition in wall-bounded flows,” Appl. Mech. Rev. 61, 030802 (2008)] has drawn much attention to the role of hairpin vortices and their origin. This Letter reports the existence of such SCSs in a compressible mixing layer and explores how their interactions with the background shear flow generate streamwise vorticity. Lagrangian particle tracking based on direct numerical simulation data is employed to trace the dynamic evolution of such structures. Evidence shows that localized three-dimensional waves travel coherently during the early transition stage, in good agreement with the behavior of SCSs in boundary layer transition. Through visualization of disturbance amplification and statistical analysis of locally distributed high-strain rate regions, it is suggested that SCSs originate from local oblique resonance effects in mixing layers, with the motion of these structures along the mean shear flow contributing to the generation of hairpin vortices.

Abstract The orbital properties of the (as yet) small population of hot Jupiters with nearby planetary companions provide valuable constraints on the past migration processes of these systems. In this work, we explore the likelihood that dynamical perturbations could cause nearby inner or outer companions to a hot Jupiter to leave the transiting plane, potentially leaving these companions undetected despite their presence at formation. Using a combination of analytical and numerical models, we examine the effects of stellar evolution on hot Jupiter systems with nearby companions and identify several possible outcomes. We find that while inner companions are generally unlikely to leave the transiting plane, outer companions are more prone to decoupling from the hot Jupiter and becoming nontransiting, depending on the system’s initial orbital architecture. Additionally, we observe a range of dynamical behaviors, including overall stability, inclination excitation, and, in some cases, instability leading to the ejection or collision of planets. We also show that the effect of stellar obliquity (with respect to the mean planet of the planets) is to amplify these effects and potentially cause outer companions to attain nonmutually transiting configurations more often. Our results highlight the complex dynamical pathways shaping the architectures of hot Jupiter systems.

This examine examines the impact of virtual transformation on monetary information accuracy in small organizations working in Iraq, using the Technology-Organization-Environment (TOE) framework because the theoretical foundation. Through a comprehensive survey of 2 hundred small commercial enterprise owners and economic managers, decided on via stratified random sampling from the Iraqi Ministry of Commerce database, information was analyzed the usage of structural equation modeling (SEM) with AMOS 26.0. The observe employed rigorous psychometric validation along with confirmatory factor evaluation (CFA), reliability testing (Cronbach's α > 0.80), and discriminant validity evaluation. Results reveal that virtual transformation extensively enhances financial records accuracy (β = zero.687, p < zero.001), with financial statistics quality serving as a substantial mediator (oblique effect = 0.234, p < 0.001). The take a look at well-known shows sizeable enhancements in mistakes discount (79. Three%), reporting efficiency (seventy-six. Four%), and operational fee financial savings (60%). Key obstacles encompass implementation charges, virtual literacy gaps, and organizational resistance.

LES investigation of oblique inflow effects on propeller cavitating tip vortex

Study DesignRetrospective cohort study.PurposeTo evaluate the effect of discrepancies between sacral and pelvic obliquity on postoperative disk wedging below the lower instrumented vertebra in Lenke type 5 adolescent idiopathic scoliosis (AIS).Overview of LiteraturePrevious studies have not fully explored the effect of discrepancies between sacral and pelvic obliquity on postoperative outcomes in patients with Lenke type 5 AIS.MethodsData from 35 patients with Lenke type 5 AIS (mean age, 14.7±1.8 years) followed for a minimum of 5 years were retrospectively analyzed. We investigated the effect of sacral coronal obliquity (S angle) and pelvic coronal obliquity (P angle) on postoperative coronal radiographic parameters. The angle between the S and P angles was defined as the sacral and pelvic (SP) angle. The patients were grouped by preoperative SP angle (<5°, n=23; ≥5°, n=12). Pre- and post-operative radiographic parameters were compared to determine whether the preoperative SP angle affected postoperative spinal alignment.ResultsThe discrepancy between SP obliquity was reduced by correction surgery 5 years postoperatively. The mean lumbar Cobb angle correction rate in the ≥5° group was significantly lower than that in the <5° group (52.1%±17.8% vs. 65.5%±12.7%), and the mean wedge angle below the lower instrumented vertebra (LIV) in the ≥5° group was significantly larger than that in the <5° group (9.0°±2.6° vs. 4.7°±3.4°) 5 years postoperatively. No significant between-group differences were observed in age, Risser grade, thoracic Cobb angle correction rate, LIV–central sacral vertical line (CSVL), and C7–CSVL. The Scoliosis Research Society-22 outcomes were comparable between the two groups.ConclusionsThe ≥5° group exhibited a larger wedge angle below the LIV and lower lumbar Cobb angle correction rate than the <5° group 5 years postoperatively. Preoperative discrepancies between SP obliquity should be considered when planning corrective surgery for patients with Lenke type 5 AIS.

Abstract Titan is the only icy satellite in the solar system with a dense atmosphere. This atmosphere is composed primarily of nitrogen with a few percent methane, which supports an active, methane‐based hydrological cycle on Titan. The presence of methane, however, is intriguing, as its lifetime is likely much shorter than the age of the solar system due to its irreversible destruction by UV photolysis. To explain Titan's current atmospheric methane abundance, it is hypothesized that a replenishment mechanism is needed. One such mechanism may be crater forming impacts; a methane‐clathrate layer potentially covering the surface of Titan may act as a reservoir that releases methane when disrupted by impacts. Here, we perform impact simulations into methane‐clathrate layers to investigate the amount of methane released via impacts. Our simulations show that the amount of methane released into the atmosphere depends on both the impactor size and the methane‐clathrate layer thickness. A single 20‐km‐diameter impactor releases up to 1% of Titan's current atmospheric methane mass; the effect of impact obliquity and surface porosity may further increase the released mass by a factor of 2–3. The release rate from impacts is lower than the net loss rate by photolysis, but the released methane mass via impacts can enhance the lifetime of methane in Titan's atmosphere by up to 3%. Menrva‐sized (400 km diameter) crater‐forming impacts directly liberate 15% of Titan's current atmospheric methane. The direct heating of the atmosphere by the impactor might contribute to additional crustal heating and methane release.

PurposePart 1 of the study investigated image quality associated with oblique incidence of light on a multisegment lens (Hoya MiyoSmart) intended to treat myopia development. Part 2 investigates power corrections associated with oblique incidence.MethodsModelling and ray tracing were carried out with lenses of −4 D distance power and, to a lesser extent, +0.25 D. Ray tracing simulations were done for the lens by itself, an eye model by itself and the combination. These simulations were for the static situation of peripheral vision when the eye looks through the lens centre and for central (foveal) vision when the eye rotates to look at objects away from the lens optical axis. The outcome was power correction of the optics, that is, the difference between the nominal power of the distance correction provided by the carrier lens under specific conditions and the actual power. This was determined across the field to about 45° and across the pupil for certain field angles. Most investigations were performed for distance vision, but some were for near objects with an accommodating version of the model eye.ResultsIgnoring intended multisegment effects, the quality of optics associated with peripheral vision was poor. There was considerable astigmatism (cylinder) across the field and high variation in astigmatism across the pupil. The added effects of the lens and eye were similar to those of their combination. For the accommodated eye model with an object at 250 mm, results were similar to those obtained with the unaccommodated model viewing a distant object. For foveal vision with the rotating eye, optics were relatively good with lower levels of astigmatism than for peripheral vision.ConclusionThe results of Part 1, finding considerable effects of the obliquity of incidence associated with peripheral vision and with foveal vision for the rotating eye, were supported by the power corrections.

Bioturbation structures preserved in the c. 260 m long Toarcian section of the Llanbedr (Mochras Farm) borehole (Wales, UK) display cyclic occurrences influenced by astronomical forcing. Depth-domain data series of ichnotaxa distribution were analysed using recurrence plots, which allow observation of cyclic patterns across various scales simultaneously and assessment of the varied responses of different tracemakers to the influence of particular orbital terms. Phycosiphon and Schaubcylindrichnus occurrences reflect the combined effect of precession, obliquity, and short eccentricity. In turn, conditions favouring the development of undulated bedding and the Thalassinoides and Trichichnus tracemakers were primarily controlled by the long eccentricity. Disruptions in the plots likely result from average sedimentation rate changes, and stress conditions experienced by benthic fauna during the latter stages of the Early Toarcian carbon isotope excursion. Generally, the plots reveal patterns characteristic of systems governed by deterministic chaos, with pronounced cyclic components.

IntroductionMultisegment (MS) spectacles are intended to slow myopia progression by modifying images falling on the peripheral retina. Some published optical treatments of these lenses assume normal incidence of light at the surfaces, but images falling on the peripheral retina are usually associated with oblique ray pencils. Here, we model representative images of point objects produced by the Hoya MiyoSmart MS spectacle lens when oblique ray pencils are used.MethodsVarious imaging aspects of the MS lens alone and in combination with a suitable accommodating eye model for a 4D myope were evaluated using the Optical Design program Ansys Zemax OpticStudio. Configurations studied included object points at vergences of zero and –4 D, with the objects being either on the lens axis or at a field angle of about 30°. The effect on foveal vision of rotating the axis of the eye with respect to that of the lens was also considered. Images of point objects were described in terms of spot diagrams and fast Fourier transform point‐spread functions.ResultsSymmetry and overall optical quality of images decreased with the obliquity of the ray pencils, due to the increased off‐axis aberrations of the lens and the eye. Images of near object points were strongly affected by the level of accommodation: optimal retinal image quality occurred when accommodation brought the carrier lens focus close to the retina, rather than that of the lenslets.ConclusionsAttempts to understand why MS lenses slow myopia progression need to consider the way in which through‐focus retinal image quality changes with obliquity of the ray pencils across the visual field and the possible effects of ocular accommodation.

Abstract Obliquity can shape the habitability of a planet by changing the seasonal availability of incident solar radiation. Changes in incident radiation can lead to changes in the availability of light, temperature, ocean circulation, stratification, and corresponding nutrient availability, all of which are important in determining ocean net primary productivity (NPP). Moreover, a fraction of the carbon assimilated by phytoplankton is sequestered in the deep ocean. Therefore, changes in productivity can alter the distribution of CO2 between the ocean and atmosphere. In this study, we investigate the effects of obliquity on ocean NPP and the atmospheric CO2 concentration using ROCKE-3D fully coupled to the NASA GISS Ocean Biogeochemistry Model. We find sea surface temperature primarily controls the NPP response, with both properties reaching a maximum at an obliquity of 45°. We find that the response of the seasonal amplitude of NPP to obliquity is controlled primarily by photosynthetically available radiation and secondarily by changes in nutrient availability. We also find that atmospheric CO2 increases in response to obliquity, with a minimum at 15° and a maximum at 60°. The obliquity-driven CO2 changes are controlled primarily by temperature-driven solubility changes, with circulation and biology either enhancing solubility-driven changes at low obliquities or acting against and partially offsetting solubility-driven changes at higher obliquities. The magnitude of obliquity-driven changes is likely too small to be detectable, though future studies are needed to determine whether changing obliquity simultaneously with other orbital parameters can lead to larger, potentially detectable changes in NPP and CO2.

IntroductionMilankovitch theory has extensive application in sequence stratigraphy and the establishment of time scales. However, it is rarely applied to shallow strata rich in hydrates. Cyclostratigraphic analysis of the Quaternary unconsolidated sediments can help identify climate and sea level changes that correspond to orbital cycles and improve our understanding of the dynamic evolution of hydrates.MethodsUsing the natural gamma-ray log data from the deepwater area well W01 in the Qiongdongnan Basin, Milankovitch cycle analysis was conducted to identify the primary astronomical period in W01. Anchored to existing AMS-14 C age from bivalve shell as reference point, an astronomical age scale of W01 was established. Simultaneously, through the analyses of major trace elements and total organic carbon content (TOC) in sediment samples, how astronomical orbital cycles influenced past environmental conditions. Furthermore, employing sedimentary noise models, the relative sea level change of well W01 was reconstructed.ResultsSedimentary cycles of 27.34 m and 6.73 m were identified in the GR data from well W01, corresponding to orbital periods of 405 kyr and 100 kyr eccentricity, with a duration of approximately 2.5 Myr. The spectral analysis of paleoenvironmental proxies reveals a sedimentary cycle of approximately 27 m, while the sedimentary noise model reconstructs the fluctuating rise in sea level change. An obliquity modulation period of approximately 170 kyr was identified in the TOC data, which may reflect the combined effects of obliquity and other orbital parameters.DiscussionSpectral analysis of paleoenvironmental indicators showed that long eccentricity cycle had varying degrees of influence on changes in paleoclimate, paleosalinity, and paleoredox conditions. Additionally, a 1.2 Myr cycle was identified as a significant factor influencing sea level changes during the early Pleistocene in the South China Sea (SCS). In addition, it is confirmed that the dominant period of the glacial-interglacial cycle in the SCS from 0.6 Ma to the present is 100 kyr period. Synthesize the above analysis, during phases of low amplitude in the 405 kyr cycle or minimum value of the 100 kyr cycle, which are associated with lower temperature, conditions become more conducive to hydrate accumulation.

The "oblique effect" refers to the reduced visual performance for stimuli presented at oblique orientations compared to those at cardinal orientations. In the cortex, neurons that respond to specific orientations are organized into orientation columns. This raises the question: Are the orientation signals in the iso-orientation columns associated with cardinal orientations the same as those in the iso-orientation columns associated with oblique orientations, and is this signal influenced by experience? To explore this, iso-orientation columns in visual area 18 were examined using optical imaging techniques. Kittens were raised under either standard or modified conditions, including total darkness or rhythmic light stimulation through one or both eyes, which could potentially disrupt the orientation tuning of visual neurons. A signal profile around the pinwheel center was calculated to assess the distribution of the orientation signal within the hypercolumn. This profile exhibits a sinusoidal pattern with identifiable minima and maxima. To emphasize that these amplitude variations are localized within a specific circle rather than throughout the entire optical map, we used the terms "local minima" and "local maxima." The number of local maxima in areas corresponding to oblique orientations was similar to those in regions associated with vertical orientations. The highest number of local maxima was found in horizontal iso-orientation columns, indicating a "horizontal bias." This finding may be related to the postnatal development of sensory-sensory and sensory-motor integrations involving the visual system. We propose that the data presented should be incorporated into mathematical models of visual cortex activity, as well as vision itself.