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In this article, a dual-stage positioning system for precisely tracking continuous scan and step scan profiles to meet the high-precision dynamic positioning requirements of space optical instruments is reported. A piezoelectric walking stage provides a long-stroke platform to which a short-stroke voice coil-actuated shuttle is mounted. The shuttle corrects for submicrometer deviations in the walking stage position and is designed with a low resonant frequency to passively reject disturbances produced by the walking stage. Both the walking stage and shuttle are instrumented with high-resolution interferometric encoders and a feedback system regulates the shuttle's position to achieve less than 7 nm RMS position error for constant velocity references of up to 0.5 mm/s. The shuttle is also capable of tracking step scan profiles with 10 ms settling times and 1.1 nm RMS position errors for steps up to 500 nm.

According to the challenge-hindrance model of stress (CHM), employees' appraisal of potential stressors may split into two distinct dimensions that either interfere with or enhance employees' functioning. This work expands the CHM framework by investigating whether employees' appraisal of the challenge-hindrance of COVID-19 predicts job insecurity and performance. It explores the relationship between the appraisal of the challenge-hindrance of COVID-19 and employees' job performance while incorporating the mediating role of job insecurity and the moderating role of COVID-19 Fear. Data were collected from 257 employee-supervisor dyads. As hypothesized, perceived job insecurity mediated the associations between COVID-19 hindrance and challenge appraisals and job performance. Fear of COVID-19 further moderated the association between hindrance appraisal and job performance and enhanced the indirect relationships between hindrance, job insecurity, and job performance. Unlike most studies that focus only on the adverse outcomes of COVID-19 stressors, this study examines the potential positive effects of challenge appraisals of the COVID-19 crisis. [ABSTRACT FROM AUTHOR]

As one of the most common spatial light modulators, linear micromirror arrays (MMAs) based on microelectromechanical system (MEMS) processes are currently utilized in many fields. However, two crucial challenges exist in the fabrication of such devices: the adhesion of silicon microstructures caused by anodic bonding and the destruction of the suspended silicon film due to residual stress. To solve these issues, an innovative processing method assisted by temporary anchors is presented. This approach effectively reduces the span of silicon microstructures and improves the Euler buckling limit of the silicon film. Importantly, these temporary anchors are strategically placed within the primary etching areas, enabling easy removal without additional processing steps. As a result, we successfully achieved wafer-level, high-yield manufacturing of linear MMAs with a filling factor as high as 95.1%. Demonstrating superior capabilities to those of original MMAs, our enhanced version boasts a total of 60 linear micromirror elements, each featuring a length-to-width ratio of 52.6, and the entire optical aperture measures 5 mm × 6 mm. The linear MMA exhibits an optical deflection angle of 20.4° at 110 Vdc while maintaining exceptional deflection flatness and uniformity. This study offers a viable approach for the design and fabrication of thin-film MEMS devices with high yields, and the proposed MMA is promising as a replacement for digital micromirror devices (DMDs, by TI Corp.) in fields such as spectral imaging and optical communication. [ABSTRACT FROM AUTHOR]

In the forefront of quantitative solar physics research using large-aperture ground-based solar optical telescopes, high-contrast observation along with high-accuracy polarimetric measurement in the solar active region are required. In this paper, we propose a novel high-contrast imaging telescope construction with a 60 cm medium aperture, namely, the PAthfinder in Solar Adaptive Telescope (PASAT), in which a deformable secondary mirror is used as the adaptive optical correction device and a symmetrical optical path design is employed, leading to the least Muller matrix polarization instruments. The telescope can provide a high-resolution magnetic field with high accuracy for the solar active regions, as well as high-contrast images with a superior signal-to-noise ratio and photometric accuracy of the solar photosphere and chromosphere. These data will be directly used for a better understanding of the evolution and release of magnetic energy, which will help in improving space weather forecasting. Meanwhile, PASAT will accumulate the relevant techniques for constructing similar, larger solar telescopes in the future. [ABSTRACT FROM AUTHOR]

To design a perfect reconstruction quadrature mirror filter is an area of concern due to its importance in numerous applications of digital signal processing. For perfect reconstruction, its performance is evaluated in terms of stop-band error, pass-band error, and measure of ripple. The major challenge in quadrature mirror filter bank is to achieve perfect reconstruction on the signal after passing through it. In this work, to achieve perfect reconstruction, an objective function is expressed as a weighted sum of mean-square pass-band error, mean-square stop-band error, and measure of ripple. The objective function is minimized to get the optimum filter coefficients for the low pass prototype filter of the filter bank by employing a recently developed, gradient-free, population-based Harris hawks optimization technique. This technique is inspired by the different intelligent attacking strategy and surprise pouncing behavior of Harris hawks. For fast convergence and search capability enhancement, an improved Harris hawks optimization technique is proposed which is formed by using the well-known mutation mechanism of differential evolution based optimization technique into the exploration phase of the Harris hawks optimization technique. The results obtained from the proposed technique are compared with the previously reported evolutionary optimization techniques based designs. A significant improvement in performance attributes has been attained in comparison to earlier reported techniques of filter bank design. [ABSTRACT FROM AUTHOR]

Ancient Chinese bronzes, particularly bronze mirrors, often develop a fatty, oily, or greasy film on their surface, known as patina. This film can appear silvery, green, or black. Bronze mirror samples from the Spring and Autumn Period (770–476/403 BCE) to the Ming Dynasty (1368–1644 CE) were analyzed using a systematic approach that included super depth of field three-dimensional microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM–EDS), Raman spectroscopy, and THM-Py-GC/MS. The analysis indicates the presence of advanced organic acid lead in the matrix of ancient bronze mirrors. The ancient existence of the lost wax method combined with the mould method of bronze casting technology is verified through simulation experiments and ancient literature. Ancient bronze mirrors may have utilized this technique, with advanced organic acid lead remaining in the mirror mould that entered the bronze mirror matrix during pouring. The Lead organic acids in bronze mirrors readily precipitate on the surface and cover the mirror. The change in the greasy sheen on the surface of the bronze mirror may be related to the degree of corrosion. If the mirror's corrosion level is low, the organic acid lead film remains transparent. If the level of corrosion is significant, the organic acid lead film may darken in color due to oxidation, aging, hydrolysis, or microbial activity. [ABSTRACT FROM AUTHOR]

The paper presents a description of the developed technique for monitoring of the mirror positions of the Imaging Atmospheric Cherenkov telescopes based on the Bokeh method. The telescopes are part of the experimental complex TAIGA, located in the Tunka valley (Republic of Buryatia, Russia), 50 km from Lake Baikal. The results of the analysis of CCD-camera images to determine the position of mirror segments are presented. [ABSTRACT FROM AUTHOR]

The dependence of the structure and stability of strongly asymmetric stationary states of a superradiant laser with a slightly asymmetric low-Q Fabry–Perot cavity on its length, reflection factors of mirrors, and pumping level is studied. The states are related to a self-consistent inhomogeneous half-wavelength population inversion grating. The possibility of the existence of two dynamic phase transitions from a stationary (monochromatic) state of this type to a nonstationary one is established: (1) a dissipative superradiant transition to a regime with a quasi-continuous lasing spectrum (in a weakly asymmetric cavity) and (2) a self-modulation transition to a regime with a discrete lasing spectrum. It is shown that the latter can be caused by excitation of both polariton and electromagnetic laser modes due to resonant Rabi oscillations of active centers with a sufficiently long phase relaxation time. [ABSTRACT FROM AUTHOR]

Introduction: To evaluate the manual dexterity of dentistry students and academicians when using a mirror according to increasing professional experience. Materials and Methods: The study included 72 subjects, grouped according to professional experience 5th year dentistry students (DS) accepted as no experience—academicians with 1–4 years experience (A5L)—academicians with ≥5 years experience (A5M). Direct and indirect visualisation using the mirror was evaluated with the completion times of the O'Connor Finger Dexterity Test. Results: The hand grip strength values of both left and right hand were found to be statistically significantly higher in all the males than in the females (p <.05). The indirect test times (ITT) using the mirror were significantly longer for males than for females (p =.001), and no significant difference was determined between the genders in the direct test times (DTT) (p >.05). For all the study participants, DTT shortened as professional experience increased (p <.05). In addition, the mean values of both DTT (p =.031) and ITT (p =.028) in the DS group were statistically significantly longer than the A5M group. Conclusion: With increasing professional experience, manual dexterity was determined to increase, and females were found to be more successful in the direct manual dexterity tests independently of the groups. The statistical significance between the DS and A5M groups, especially in the hand dexterity test with a mirror, shows the importance of experience. The study results demonstrated that professional manual dexterity in dentistry can be developed with increasing practical application. [ABSTRACT FROM AUTHOR]

At-wavelength metrology of X-ray optics plays a crucial role in evaluating the performance of optics under actual beamline operating conditions, enabling in situ diagnostics and optimization. Techniques utilizing a wavefront random modulator have gained increasing attention in recent years. However, accurately mapping the measured wavefront slope to a curved X-ray mirror surface when the modulator is downstream of the mirror has posed a challenge. To address this problem, an iterative method has been developed in this study. The results demonstrate a significant improvement compared with conventional approaches and agree with offline measurements obtained from optical metrology. We believe that the proposed method enhances the accuracy of at-wavelength metrology techniques, and empowers them to play a greater role in beamline operation and optics fabrication. [ABSTRACT FROM AUTHOR]

Knife-edge imaging is a successful method for determining the wavefront distortion of focusing optics such as Kirkpatrick-Baez mirrors or compound refractive lenses. In this study, the wavefront error of an imperfect elliptical mirror is predicted by developing a knife-edge program using the SHADOW/OASYS platform. It is shown that the focusing optics can be aligned perfectly by minimizing the parabolic and cubic coefficients of the wavefront error. The residual wavefront error provides precise information about the figure/height errors of the focusing optics suggesting it as an accurate method for in situ optical metrology. A Python program is developed to design a customized wavefront refractive corrector to minimize the residual wavefront error. Uniform beam at and out of focus and higher peak intensity are achieved by the wavefront correction in comparison with ideal focusing. The developed code provides a quick way for wavefront error analysis and corrector design for non-ideal optics especially for the new-generation diffraction-limited sources, and saves considerable experimental time and effort. [ABSTRACT FROM AUTHOR]

This article explores cinematic representations of American military interventions in Iraq and Afghanistan, examining documentary and fiction films from American, Iraqi, and Afghan perspectives. The article argues that these films often fail to communicate meaningfully with domestic and international audiences effectively, instead remaining 'asymptotic' or 'uroboric' in their rhetorical and communicative impact. I highlight the ethical challenge faced by filmmakers, whether situated in the West or in the Middle East, of turning the 'traumatic mirror' back on themselves, and the difficulties in achieving successful communication and self-reflexivity. The post-9/11 era is marked by a complex intersection of realpolitik, public performatives, and moral commitments, with long-standing tensions between West and non-West persisting in new forms. Cinematic representations of these interventions serve as a window into the traumatic legacies of these conflicts and the ongoing struggle for ethical representation, as well as a lens on the rhetorics of cinema. [ABSTRACT FROM AUTHOR]

Modern high-sensitivity spectrometers rely on photons reflecting thousands of times between extremely reflective mirrors to generate absorption pathlengths that are kilometers long. The absorption spectrum of trace gas species is enhanced when cooling the gas sample, however, should any atmospheric volatiles condense within the gas cell, the highly-reflective mirrors may become marred, drastically cutting down the effective optical path length. In the Martian atmosphere, the first volatile to condense is typically water vapor, thus understanding the variability of the water frost point is essential for determining the performance limit of any optical instrument. We will examine these performance limits and map the maximum temperatures at which water vapor will condense on the Martian surface with respect to a model instrument being prepared for flight. The variability of the frost point with time and solar longitude (L s) therefore reveals areas of the Martian surface at which the precision of a high-sensitivity spectrometer is optimized. We find that the optimal performance is achieved during northern fall and winter (L s = 180°–360°) at polar and mid-latitude locations in the northern hemisphere, and during northern spring (L s = 0°–90°) at equatorial and mid-latitude locations in the southern hemisphere when the frost point reaches the lowest maximums. • Instrument precision is higher with lower temperatures without risk of frost. • On Mars, water vapor can condense within instrumentation, decreasing the precision. • The water frost point (FP) varies based on the atmospheric water vapor abundance. • Northern mid-latitude and polar regions have lower FPs during fall and winter. • The FPs at Gale crater near the equator have little variation throughout the year. [ABSTRACT FROM AUTHOR]

While scholars have relied on societal cleavages to explain the origins and evolution of party systems in Western democracies, drawing that link in Latin America and the Caribbean has been more challenging. Guyana is an exception to the norm. Its party system has aligned ethnically since independence in the 1960s. The People's National Congress mostly appeals to the Afro-Guyanese, and the People's Progressive Party largely draws support from the Indo-Guyanese. However, in recent decades, the country has experienced relevant demographic shifts that force a reconsideration of the predominance of ethno-racial traits as fuelling inter-party competition. We use the AmericasBarometer to examine the individual-level ethno-racial, ethno-religious, and ideological correlates of partisanship from 2010 to 2016. The results indicate that ethno-racial divisions have lost salience as ethno-religious features have become a more prevalent source of partisan attachments. We conclude that the correlates of partisanship in Guyana mirror its broader socio-demographic transformation. [ABSTRACT FROM AUTHOR]

The article is a review of the book "Un deambular circular: estudio sobre la obra de Gonzalo Hidalgo Bayal" written by Ana Calvo Revilla. The book seeks to study and vindicate the work of the Spanish narrator Gonzalo Hidalgo Bayal, who is not very well-known by the general public despite being an active author who regularly publishes. The author contextualizes Hidalgo Bayal's life and work, highlighting his influence from Spanish and foreign literary traditions, as well as the quality of his asides and digressions and the metaphorical nature of his narrative. The article also presents a review of two books: "RILCE 40.2" and "The Epic Mirror," which analyze Hidalgo Bayal's creative work and study texts of the epic genre in the Peruvian colony, respectively. Both books are considered important contributions in their fields and are recommended for scholars of the mentioned authors. [Extracted from the article]

Linear thermal expansion coefficient, which is vital for measuring the thermal expansion characteristics of metals, has been attracting considerable attention globally. Herein, a novel design based on Fresnel bimirror has been developed. In this design, when the upper end of the object to be measured comes in contact with a tilted double‐sided mirror, the temperature rises and intersection angle of the Fresnel bimirror decreases. Meanwhile, interference fringe spacing becomes narrower, while the number of fringes increases. An imaging system based on a digital microscope and smartphone is also incorporated in this design, which records the changes in the interference fringes. Then, using a self‐programmed software, the linear thermal expansion coefficients of Cu, Fe, and Al samples are determined at elevated temperatures as 17.85 ± 0.23 × 10−6/°C (αCu ${\alpha }_{C{\rm{u}}}$), 11.8 ± 0.09 × 10−6/°C (αFe ${\alpha }_{F{\rm{e}}}$), and 23.34 ±0.16 × 10−6/°C (αAl ${\alpha }_{Al}$), respectively, with a relative error of less than 1.6%. A cooling process is also designed, and the average value of the linear thermal expansion coefficient of metal samples during heating and cooling conditions is determined. The measurement results obtained via the finite‐method simulation demonstrate the feasibility and reliability of the system. Overall, this study provides a new idea for measuring the linear thermal expansion coefficient of metals. [ABSTRACT FROM AUTHOR]

Ulnar dimelia, also known as "mirror hand disorder", is a rare developmental disorder affecting the upper limb. Primarily, it involves the duplication of fingers, carpal bones, metacarpals, or ulna along the sagittal axis, and is often accompanied by the absence of the radius or thumb. The anomaly presents challenges in both bone and soft tissue development, impacting limb functionality and affecting a child's quality of life. We present the case of a one-year-old girl with unilateral ulnar dimelia. Surgical intervention was considered to address functional and aesthetic concerns. The surgery involved creating an opposable thumb from preaxial fingers through a carefully tailored approach. Post surgical therapy included physiotherapy and psychotherapy to ensure both physical functionality and psychological adjustment. The surgical procedure successfully provided an adequate grip pattern, and the patient demonstrated age-appropriate use of the modified hand at the six-month follow-up. Comparison with similar cases highlights the diversity in ulnar dimelia presentations and the need for customised surgical solutions. The timing of surgery is typically recommended between one and two years, considering both anatomical readiness and the advantages of cerebral plasticity in young patients. [ABSTRACT FROM AUTHOR]

Summary: This study deals with the results of the 2023 fieldwork at the extramural cemetery of the Late Bronze Age harbour city of Hala Sultan Tekke. One of the three excavated tombs in 2023 was the undisturbed Chamber Tomb XX, which is dated around 1300 BC. It contained a riveted bronze mirror, a rare type in Cyprus at that time, which is part of a mortuary context of four individuals out of a total of 17 individuals and 264 complete objects, many of them imported from a vast area, which includes the Mycenaean, Minoan, Egyptian and Levantine cultures. The current paper presents this mirror and associated contexts. As regards the provenance of the mirror, the Aegean is suggested as the area of manufacture, and more precisely Crete, suggesting potential evidence of direct contact between individuals from Crete and Hala Sultan Tekke. [ABSTRACT FROM AUTHOR]

String on AdS3 × S3 × T4 backgrounds are known to be classically integrable in the presence of a mixture of Ramond-Ramond and Neveu-Schwarz-Neveu-Schwarz fluxes. It is expected that this results in the existence of a well-defined factorised worldsheet S matrix. In order to use integrability to compute the string spectrum we need such a factorised S matrix to exist also for the "mirror" model, obtained by a double Wick rotation of the original worldsheet theory. In the mixed-flux case the mirror model has a complex Hamiltonian, which raises questions on its well-definedness. In the paper we study the worldsheet tree-level S matrix of the original and mirror model and discuss some necessary conditions for the integrability and reality of the spectrum. [ABSTRACT FROM AUTHOR]

This article explores the use of smartphone cameras in conducting physics experiments to determine the transverse size and position of virtual images formed by lenses and a plane mirror. The authors explain that virtual images can be challenging for students to understand as they cannot be projected onto a screen. By taking photographs of the virtual images and using readily available software, the transverse width of the image on the camera sensor can be determined. The article provides theoretical equations and experimental procedures for determining the width and position of virtual images produced by lenses and a plane mirror. The authors present experimental results and data analysis for the virtual image width and position using Apple iPhone cameras, including the focal lengths of the camera lenses and pixel sizes. The measurements and calculations are done using equations and formulas, and the results show the virtual image distances and focal lengths for both lenses, with comparisons made to standard methods. The article also discusses the concept of magnification and includes tables and graphs to illustrate the data. Overall, the article emphasizes the simplicity and importance of using smartphone photography in physics experiments and highlights the accuracy and precision that can be achieved with this method. The authors, Sanjoy Kumar Pal, Soumen Sarkar, and Surajit Chakrabarti, have expertise in physics education and research. [Extracted from the article]

First‐arrival travel‐time tomography is frequently used in ocean‐bottom seismometer surveys for estimating subsurface velocity. However, due to a lack of seismometer stations or ray sampling, the tomographic images' spatial resolution and quality are typically low. Inspired by the multiple imaging of ocean‐bottom seismometer data, in this study, I developed a mirror tomography method to incorporate the travel times of refraction multiples in first‐arrival travel‐time tomography. Specifically, the travel times of refraction multiples were treated as virtual first‐arrival travel times from the mirror positions of the stations. This technique enhances ray coverage and stabilizes the inversion. I confirmed that the travel times of refraction multiples were consistent with the first‐arrival travel times calculated using numerical modelling at the mirror position of the station. Synthetic examples showed that the mirror tomography scheme may enhance ray coverage and model resolution. Mirror tomography may compensate for the uneven distribution of travel‐time picks caused by the loss of the ocean‐bottom seismometer. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate mirror visual feedback (MVF) as a training tool for brain-computer interface (BCI) users. This is because approximately 20–30% of subjects require more training to operate a BCI system using motor imagery. Electroencephalograms (EEGs) were recorded from 18 healthy subjects, using event-related desynchronization (ERD) to observe the responses during the movement or movement intention of the hand for the conditions of control, imagination, and the MVF with the mirror box. We constituted two groups: group 1: control, imagination, and MVF; group 2: control, MVF, and imagination. There were significant differences in imagination conditions between groups using MVF before or after imagination (right-hand, P = 0.0403; left-hand, P = 0.00939). The illusion of movement through MVF is not possible in all subjects, but even in those cases, we found an increase in imagination when the subject used the MVF previously. The increase in the r2s of imagination in the right and left hands suggests cross-learning. The increase in motor imagery recorded with EEG after MVF suggests that the mirror box made it easier to imagine movements. Our results provide evidence that the MVF could be used as a training tool to improve motor imagery. NEW & NOTEWORTHY: The increase in motor imagery recorded with EEG after MVF (mirror visual feedback) suggests that the mirror box made it easier to imagine movements. Our results demonstrate that MVF could be used as a training tool to improve motor imagery. [ABSTRACT FROM AUTHOR]

The positioning of minoritised and racialised groups such as Global South immigrants as deficient in knowledge, language or motivation is a form of othering prevalent in all spheres of Global North societies, and the environmental sector is no exception. In both academic literature and policy, there is an assumption that minoritised groups are "hard to reach" and less interested in sustainability than the usual white middle-class environmental subjects. But, what might the picture look like if it focused on those who have the power to make choices about whose interests matter and whose can be ignored? By holding up a mirror to the powerful and asking them to reflect on their own practices and assumptions, we centre the operation of structural inequality to show that the lack of inclusivity in sustainability policy is very often a product of structural whiteness rather than the deficiencies of racialised communities. This article draws on interviews with key informants involved in local environmental governance to explore how people in positions of power serve to obstruct, erase or facilitate the engagement of racialised communities in activities relevant for environmental change. We argue that a symmetrical approach to research and analysis is needed to avoid othering immigrants while surfacing whiteness as the context in which othering occurs. We call for greater attention to how white structural advantage shapes the design and implementation of local green agendas in order to develop just and transformative approaches to environmental policy-making. [ABSTRACT FROM AUTHOR]

Copyright of Studies in Hispanic & Lusophone Linguistics is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a study on the performance degradation of amorphous silica mirrors coated with silica/tantala, commonly utilized in gravitational wave interferometry measurements. The primary objective is to understand the factors contributing to the reduced performance, specifically the heightened noise observed after prolonged use of the mirrors in a vacuum. In this article, SiO 2 /Ta 2 O 5 multilayered coated sample mirrors underwent analysis through x-ray photoemission spectro-microscopy, atomic force microscopy, and Raman spectroscopy, before and after exposure to a contaminating vacuum environment. Our findings revealed the possible correlation between the deterioration in mirror performance and an upsurge in contaminant carbon and defect populations within the silicon dioxide structure. [ABSTRACT FROM AUTHOR]

In order to improve the control of a moving mirror control system and enhance the anti-interference ability of the system, active disturbance rejection control (ADRC) with parameter autotuning is proposed and applied to control a rotary voice coil motor (RVCM). Improved snake optimization (I-SO) was applied to tune and optimize ADRC's key parameters. To obtain excellent parameters efficiently, in the population initialization phase of SO, the quality and diversity of initial solutions were improved through a chaotic elite opposition learning algorithm. In the local search phase, a sine and cosine (SC) search mode was introduced to enhance the local search ability of SO. The simulation results show that I-SO can effectively find the ideal parameters. I-SO has excellent search capability and stability. The experimental control system of a moving mirror was established, and the effectiveness of the parameters optimized by I-SO was verified. ADRC with parameter autotuning showed excellent control in the moving mirror control system, and the stability of the optical path scanning speed reached 99.2%. [ABSTRACT FROM AUTHOR]

In this study, the aim is to design and develop a 3D acquisition, visualization, and interaction framework to preserve cultural heritage and provide new ways to enable museum visitors and cultural audiences to virtually interact with cultural objects. Indeed, cultural assets are nowadays at higher risk and most cultural institutions prohibit visitors from physically manipulating their collections. The main motivation behind our framework is to enable end-user interaction with high valuable cultural objects while addressing cost-effectiveness concerns as well as minimizing the time required to digitize and generate 3D models of cultural heritage objects. The design idea of our framework is to allow interaction with the protected assets' 3D representation using a real-world 3D screen equipped with a depth sensor namely the leap motion controller. Our framework is an end-to-end solution that optimizes all the stages of the 3D acquisition, pre-processing, visualization, and interaction pipeline while providing contributions to its stages. It achieves good quality results thanks to the use of machine learning in the acquisition and modeling stages. Indeed, we adapted a prior preprocessing work that performs super-resolution and motion interpolation on the acquired data. The preprocessed data is then used for the generation of the 3D models using photogrammetry, which optimizes the quality of the resulting 3D models. The created 3D models are then adapted for the visualization and interaction stages. A novel visualization and interaction paradigm is introduced to enable a real-world experience for museum visitors through a 3D screen called "the Looking Glass". The interaction with the 3D content is achieved through a motion sensor used to design our new interaction component of the framework. We propose two new interaction systems suitable for various user profiles focusing on their experience in dealing with motion sensors. The end-to-end framework tested in a museum environment was evaluated by cultural heritage curators and multimedia experts and found to provide an alternate reality tool for asset exhibition and a cost-effective alternative for asset exchange between cultural institutions. For the evaluation, we compared the end-user experience of our framework using various setups where users are visualizing the content through 2D screens and through the Looking glass while enabling and disabling motion interaction. The results of the evaluation suggest that the looking glass paired with the Leap motion sensor using our framework as a backend enables an alternate reality experience for museum visitors and new ways of interacting with cultural content, sharing of cultural knowledge, cultural education, and much more. [ABSTRACT FROM AUTHOR]

Since the concept of adaptive optics(AO) was proposed in 1953, AO has become an indispensable technology for large aperture ground-based optical telescopes aimed at high resolution observations. This paper provides a comprehensive review of AO progress for large aperture astronomical optical telescopes including both night-time and day-time solar optical telescopes. The recent AO technological advances, such as Laser Guide Star, Deformable Secondary Mirror, Extreme AO, and Multi-Conjugate AO are focused. [ABSTRACT FROM AUTHOR]

Copyright of Odeere is the property of Edicoes UESB and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Precision beam pointing plays a critical role in free-space optical communications terminals in uplink, downlink and inter-satellite link scenarios. Among the various methods of beam steering, the use of fast steering mirrors (FSM) is widely adopted, with many commercial solutions employing diverse technologies, particularly focusing on small, high-bandwidth mirrors. This paper introduces a method using lightweight, commercial off-the-shelf components to construct a custom closed-loop steering mirror platform, suitable for mirror apertures exceeding 100 mm. The approach involves integrating optical encoders into two off-the-shelf open-loop actuators. These encoders read the signal reflected on purposefully diamond-machined knurled screw knobs, providing maximum contrast between light and dark lines. The resulting steering mirror has the potential to complement or replace FSM in applications requiring a larger stroke, at the expense of motion speed. In the presented setup, the mirror tilt resolution achieved based on the encoder closed-loop signal feedback is 45 μ rad, with a mean slew rate of 1.5 mrad/s. Importantly, the steering assembly is self-locking, requiring no power to maintain a steady pointing angle. Using the mirror to actively correct for a constantly moving incoming beam, a 5-fold increase in concentration of the beam spot on the center of the detector was obtained compared to a fixed position mirror, demonstrating the mirrors ability to correct for satellite platform jitter and drift. [ABSTRACT FROM AUTHOR]

In this paper, we propose a variable sample-size optimistic mirror descent algorithm under the Bregman distance for a class of stochastic mixed variational inequalities. Different from those conventional variable sample-size extragradient algorithms to evaluate the expected mapping twice at each iteration, our algorithm requires only one evaluation of the expected mapping and hence can significantly reduce the computation load. In the monotone case, the proposed algorithm can achieve O (1 / t) ergodic convergence rate in terms of the expected restricted gap function and, under the strongly generalized monotonicity condition, the proposed algorithm has a locally linear convergence rate of the Bregman distance between iterations and solutions when the sample size increases geometrically. Furthermore, we derive some results on stochastic local stability under the generalized monotonicity condition. Numerical experiments indicate that the proposed algorithm compares favorably with some existing methods. [ABSTRACT FROM AUTHOR]

Copyright of WISTA Wirtschaft und Statistik is the property of Statistisches Bundesamt and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Human subjects were tested in perception of shapes of 3D objects. The subjects reconstructed 3D shapes by viewing orthographic and perspective images. Perception of natural shapes was very close to veridical and was clearly better than perception of random symmetrical polyhedra. Viewing perspective images led to only slightly better performance than viewing orthographic images. In order to account for subjects' performance, we elaborated the previous computational models of 3D shape reconstruction. The previous models used as constraints mirror-symmetry and 3D compactness. The critical additional constraint was the use of a secondary mirror-symmetry that exists in most natural shapes. It is known that two planes of mirror symmetry are sufficient for a unique and veridical shape reconstruction. We also generalized the model so that it applies to both orthographic and perspective images. The results of our experiment suggest that the human visual system uses two planes of symmetry in addition to two forms of 3D compactness. Performance of the new model was highly correlated with subjects' performance with both orthographic and perspective images, which supports the claim that the most important 3D shape constraints that are used by the human visual system have been identified. [ABSTRACT FROM AUTHOR]

Background and purpose: Research to date has lacked definitive evidence to determine whether mirror therapy promotes the recovery of upper extremity function after stroke. Considering that previous studies did not stratify patients based on structural retention, this may be one of the reasons for the negative results obtained in many trials. The goal evaluates the efficacy of TBMT (utilizing an innovatively designed mirror) versus standard occupational therapy for stroke patient's upper limb functionality. Methods and analysis: This single-center randomized controlled trial will involve 50 patients with stroke. All patients will be randomly assigned to either the task-based mirror therapy or the control group. The interventions will be performed 5 days per week for 4 weeks. The primary outcomes will be the mean change in scores on both the FMA-UE and modified Barthel Index (MBI) from baseline to 4 weeks intervention and at 12 weeks follow-up between the two groups and within groups. The other outcomes will include the Action Research Arm Test (ARAT), the Nine Hole Peg Test (9HPT), the Functional Independence Measure, and MRI. Discussion: This trial will not only to establish that task-based mirror therapy (TBMT) could improve the recovery of hand function after stroke but also to explore the underlying mechanisms. We expect that this finding will clarify the brain activation and brain network mechanisms underlying the improvement of hand function with task-oriented mirror therapy and lead to new ideas for stroke hand function rehabilitation. Trial registration: URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2300068855. Registered on March 1, 2023 [ABSTRACT FROM AUTHOR]

In this Letter, dynamic nano-thermal expansion images of reflective mirrors from high-intensity incident laser beams were observed in situ. The inspections are based on rapid 3D surface morphology changes on the reflective surfaces, captured by a Chromatic Confocal Microscope with Nanoscale Sensitivity (CCMNS). Nano-expansions of two types of coatings were studied: the E02 dielectric coating (coating 1) and the graphene-on-E02 complex film (coating 2), both applied to the same fused silica substrate. The superior thermal dissipation properties of coating 2, including enhanced heat dissipation, suppressed wavefront distortion, and its unique negative expansion coefficient, were observed. In addition to studying the effects of graphene coating, the CCMNS demonstrates an accurate and efficient approach for evaluating reflective mirrors. Moreover, the proposed methodology possesses enormous potential across various fields, ranging from estimating photonic elements dealing with high-intensity beams to physical thermal conductivity measurements. [ABSTRACT FROM AUTHOR]

This article discusses an anthology titled "Gateway to Statesmanship: Selections from Xenophon to Churchill," which explores the genre of "mirrors for princes," self-help manuals for rulers. The editor, John A. Burtka IV, argues that these texts can still be valuable for leaders today, despite the decline of ruling monarchs and the emphasis on present-focused education. The anthology includes selections from various historical periods and raises questions about the teaching of virtue and the role of literature in shaping leaders. The article suggests that while these texts offer practical wisdom, they may lack the context and engagement needed for young readers today. [Extracted from the article]

We consider a class of controlled nonlinear plants, the dynamics of which are governed by a vector system of ordinary differential equations with a right-hand side that is partially known. The study's objective is to construct a robust tracking controller with certain constraints on the state variables, assuming that the state variables and their time derivatives can be observed. The Legendre–Fenchel transform and a chosen proxy function are utilized to develop this mathematical development using the mirror descent approach, which is frequently employed in convex optimization problems involving static objects. The Average Subgradient Method (an improved version of the Subgradient Descent Method), and the Integral Sliding Mode technique for continuous-time control systems are basically extended by the suggested unifying architecture. The primary findings include demonstrating that the "desired regime"—a non-stationary analog of the sliding surface – can be achieved from the very start of the process and getting an explicit upper bound on the cost function's decrement. [ABSTRACT FROM AUTHOR]

A new guiding center particle code Guiding center Mirror Simulation is developed to simulate the evolution and confinement of the axisymmetric plasma blanket in the magnetic mirror field generated by a pair of Helmholtz coils. The simulation results indicate that this plasma blanket maintains its shape throughout evolution, and the steady state distributions of both density and electrostatic potential are obtained. The correlation between the plasma density and the characteristic confinement time is also investigated. Generally, the characteristic confinement time decreases with increasing density. When the density is low enough, it is approximately the pitch angle scattering time of the trapped electrons. When the density increases, it comes to several times of the ion transit time evaluated with the Bohm velocity. These results have the potential for experimental applications. [ABSTRACT FROM AUTHOR]

The purpose of this study is to assess the feasibility of using mirror and glass industry residues as a partial replacement for clay in clay brick production, with a focus on sustainable and eco-friendly techniques. Clay was mixed with raw sand residue (RSR) in various ratios: 87.5/12.5, 85/15, 82.5/17.5 and 80/20 wt%, extruded with the appropriate amount of moisture, dried at 110 °C and fired at temperatures from 850 to 1050 °C. Extensive analytical techniques, including thermogravimetric analysis, X-ray diffraction (XRD) mineralogical analysis, chemical characterisation using energy-dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF), and scanning electron microscopy (SEM) morphological analysis, were employed to characterise the raw materials. Mechanical and thermal properties of the fired bricks were assessed, encompassing linear shrinkage, apparent porosity, apparent density, water absorption, thermal conductivity, dilatometry analysis, bending strength, compressive strength and freeze–thaw resistance. The results demonstrated that the incorporation of RSR as an additive yielded lightweight bricks with adequate strength, particularly when fired at lower temperatures. Notably, a clay–RSR mixture containing 12.5% RSR and fired at 1050 °C displayed an optimal balance between mechanical performance and porosity, exhibiting a porosity of 13%, an apparent density of 2 g/cm3, a thermal conductivity of 0.55 W/m K, and a compressive strength of 55 MPa. Furthermore, compressive strengths of the RSR replacement bricks ranged from 25 to 45 MPa, indicating the material's potential as a sustainable alternative to reduce clay consumption in brick production. The findings of this study highlight the promising potential of mirror and glass industry residues as an eco-friendly substitute in clay brick production. [ABSTRACT FROM AUTHOR]

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At present, the LiDAR system can achieve high precision and is extensively used for indoor and outdoor mobile positioning and mapping. However, LiDAR systems still face issues in cluttered environments where strong features are absent, leading to a degradation of the LiDAR-based solution. When the carrier movement involves high-speed or prolonged exposure to the mirror wall, it can cause severe degradation issues or even positioning failures in the laser slam system. Event cameras are vision sensors inspired by biology that exhibit strong robustness in high dynamic and low texture environments, potentially leading to better performance in such environments. However, some issues with event cameras remain unresolved. In this paper, a multi-source fusion method based on EVIO, LIO and IMU trajectory layer post-processing method is proposed, which will fully consider the robustness of event camera in high dynamic environment and the high precision advantage of Lidar in conventional environment, and use an algorithm based on normalized uncertainty. The elastic multi-source fusion of event camera and LiDAR is realized and tested in realde environment. Experimental results show that the proposed algorithm can effectively improve the accuracy of event camera and LiDAR. Compared to the current more advanced algorithms, the proposed algorithm effectively addresses the problem of LIO in degraded environments. Additionally, it mitigates the scale inaccuracy and divergence of the EVIO trajectory to some extent. Compared to LIO, the algorithm can reduce the maximum position error by approximately 30% and increase the overall position accuracy by 32%. Additionally, it can significantly constrain the divergence of errors in the Y direction, improving its accuracy by about 75% and 65% compared to the LIO and EVIO algorithms, respectively. [ABSTRACT FROM AUTHOR]

We demonstrate a proof of principle of a simple all-solid-state post-compression setup for low-energy, high-repetition-rate laser pulses, where spectral broadening was performed using a combination of highly nonlinear bulk materials in a simple single-pass geometry. The 75 fs, 210 nJ pulses from an amplified 76 MHz, 15.7 W Yb:KGW oscillator after sequential spectral broadening in ZnS and YAG samples of 2 mm and 15 mm thickness, respectively, were compressed to 37 fs by means of Gires–Tournois interferometric mirrors. The post-compressed pulses with an average power of 11.47 W demonstrated reasonable spatial-spectral homogeneity of the beam with the spectral overlap parameter V > 83 % and good beam quality with M x 2 = 1.28 and M y 2 = 1.14 . [ABSTRACT FROM AUTHOR]

The interaction between technology and labour can be deceptive. The underlying commitment of enhanced working conditions which has always accompanied technological progress has not been truly fulfilled. The anticipated benefits can transform into risks. The aim of this study is to emphasize the health risks for workers and, within this framework, to analyze the available legal avenues for safeguarding their rights. These options must inherently consider the fundamental importance that the preservation of good health (comprehended as a "state of complete physical, mental, and social well-being") holds within the Italian constitutional framework. [ABSTRACT FROM AUTHOR]