Position Operators Research Articles

Ultrabroadband integrated electro-optic frequency comb in lithium tantalate.

The integrated frequency comb generator based on Kerr parametric oscillation1 has led to chip-scale, gigahertz-spaced combs with new applications spanning hyperscale telecommunications, low-noise microwave synthesis, light detection and ranging, and astrophysical spectrometer calibration2-6. Recent progress in lithium niobate (LiNbO3) photonic integrated circuits (PICs) has resulted in chip-scale, electro-optic (EO) frequency combs7,8, offering precise comb-line positioning and simple operation without relying on the formation of dissipative Kerr solitons. However, current integrated EO combs face limited spectral coverage due to the large microwave power required to drive the non-resonant capacitive electrodes and the strong intrinsic birefringence of LiNbO3. Here we overcome both challenges with an integrated triply resonant architecture, combining monolithic microwave integrated circuits with PICs based on the recently emerged thin-film lithium tantalate (LiTaO3)9. With resonantly enhanced EO interaction and reduced birefringence in LiTaO3, we achieve a fourfold comb span extension and a 16-fold power reduction compared to the conventional, non-resonant microwave design. Driven by a hybrid integrated laser diode, the comb spans over 450 nm (more than 60 THz) with more than 2,000 lines, and the generator fits within a compact 1-cm2 footprint. We additionally observe that the strong EO coupling leads to an increased comb existence range approaching the full free spectral range of the optical microresonator. The ultra-broadband comb generator, combined with detuning-agnostic operation, could advance chip-scale spectrometry and ultra-low-noise millimetre wave synthesis10-13 and unlock octave-spanning EO combs. The methodology of co-designing microwave and photonics can be extended to a wide range of integrated EOs applications14-16.

Women's Participation in Operational and High Managerial Positions in Family Businesses: Evidence From Saudi Context

Women's Participation in Operational and High Managerial Positions in Family Businesses: Evidence From Saudi Context

Video analysis of neonatal intubations using video laryngoscopy: a prospective comparison of clinical practice with resuscitation guidelines

BackgroundThe Neonatal Resuscitation Program recommends direct laryngoscopy (DL) as the primary method for neonatal intubation. Video laryngoscopy (VL) is suggested as an option, particularly for training novice operators or for...

Revisiting the matrix elements of the position operator in the crystal momentum representation

Fewer operators are more fundamental than the position operator in a crystal. But since it is not translationally invariant in crystal momentum representation (CMR), how to properly represent it is nontrivial. Over half a century, various methods have been proposed, but they often lead to either highly singular derivatives or extremely arcane expressions. Here we propose a resolution to this problem by directly computing their matrix elements between two Bloch states. We show that the position operator is a full matrix in CMR, where the off-diagonal elements in crystal momentum only appear along the direction of the position vector. Our formalism, free of singular derivative and degeneracy difficulties, can describe an array of physical properties, from intraband transitions, polarization with or without spin-orbit coupling, orbital angular momentum, to susceptibilities.

Analisa Perbaikan Sistem Kerja Menggunakan Metode RULA dan REBA di Pabrik Tahu Sumedang ABC

Health problems related to an operator's posture while working can have a major impact on productivity and efficiency levels. To minimize the possibility of disturbances in posture and injury to operators, improvements are made to work methods, adjustments to machines or work aids, rearrangement of machine positions, and changes to work movements in accordance with suggestions from the RULA analysis. At ABC's Sumedang Tofu Factory, which consists of six work stations (washing, converting, pressing, grinding, molding, and packaging), ergonomic analysis indicated that incorrect working postures could cause discomfort and fatigue in the upper body of workers. After making improvements to the working posture, the final RULA value for the milling section was reduced from 7 to 2, and for the packing section from 5 to 3, indicating that the risk had decreased to an acceptable level. The REBA method also shows a decrease in scores in the milling section from 8 to 2, and in the packing section from 5 to 3, which indicates an improvement in working posture which is better and more acceptable

Perovskite‐Inspired Cs₂AgBi₂I₉: A Promising Photovoltaic Absorber for Diverse Indoor Environments

AbstractIndoor photovoltaics (IPVs) using low‐toxicity bismuth‐based perovskite‐inspired materials (PIMs) can potentially power the growing number of Internet of Things devices sustainably. However, modest indoor power conversion efficiency (PCE) values are reported due to intrinsic limitations of PIMs, particularly regarding charge carrier separation and transport. Herein, polycrystalline Cs₂AgBi₂I₉ thin films are developed with high phase purity and study their fundamental structural and photophysical properties. The comprehensive experimental and computational study reveals unique optoelectronic properties of Cs₂AgBi₂I₉ compared to other bismuth‐containing PIMs, including weak electron‐phonon coupling and low exciton binding energy (40 meV). This study also demonstrates the feasibility of large and highly mobile polaron formation in Cs₂AgBi₂I₉, supported by the observation of a phonon bottleneck and a delayed hot carrier lifetime of over 200 ps, which suggests enhanced defect tolerance and transport properties. Motivated by the suitable bandgap of this absorber (1.78 eV), the first Cs₂AgBi₂I₉‐based IPVs are developed, achieving a PCE of ≈8% at 1000 lux. Notably, the devices maintain high performance across various indoor environments with white LED color temperatures ranging from 2700 to 6500 K. The calculated theoretical PCE limit of >40% and the promising operational stability position Cs₂AgBi₂I₉ as one of the most intriguing candidates for sustainable IPVs.

Scoping review of robotics technology in spinal surgery with highlights of the Annual Seattle Science Foundation Course.

Robotic assistance has become increasingly prevalent in spinal surgery in recent years, emerging as a tool to increase accuracy and precision and lower complication rates and radiation exposure. The 7th and 8th Annual Seattle Science Foundation (SSF) Robotics Courses showcased presentations and demonstrations from some of the field's most experiences leaders on latest topics in robotics and spinal surgery, including cutting-edge preoperative planning technologies, augmented reality (AR) in the operating room, cervical fusion with transpedicular screws, and neuro-oncologic management. We provide a scoping review of the use of robotics technology in spinal surgery featuring highlights from the 7th and 8th Annual SSF Robotics Courses. A scoping review of the literature was conducted (last search conducted in July 2024). Key search terms included "robotic assistance", "spine surgery", and "robotic technology" on the PubMed database. Additionally, highlights are included from the 7th and 8th Annual SSF Robotics Courses. Applications of navigation robotics span subspecialties of spine surgery including deformity correction, minimally invasive approaches, lateral single position operations, spinal oncology, and cervical fusion. Tips on overcoming traditional obstacles of robotics integration such as streamlining staff workflow and adoption while financing robotic-assisted technology are shared. Future directions of robotics enhanced with AR may further guide surgeon decision-making, assist in more practical fashion intraoperatively, and optimize patient outcomes. While improved precision and accuracy, less radiation, and standardization of procedures represent current advantages of robotic-assistance across spine surgery, robotics in spine surgery will usher more transformative changes to patient care and operative skill in coming years.

DESAFIOS DO MERCADO DE TRABALHO: UMA ANÁLISE DAS OPORTUNIDADES E BARREIRAS À EMPREGABILIDADE EM SANTA ROSA/RS

This study explores the labor market in Santa Rosa/RS, seeking to understand the local dynamics and challenges related to talent recruitment and retention. The region faces difficulties in attracting and retaining qualified professionals, which impacts economic and social development. Age diversity also emerges as an important trend, with companies increasingly valuing employees of different age groups. However, retaining younger talent presents additional challenges, given the difference in expectations and interests between generations. The main objective of the study was to identify the factors that hinder the recruitment and retention of talent in the local labor market, in addition to analyzing how these dynamics affect the development of the region. The study aims to provide a foundation for developing strategies that align labor supply and demand, promoting an inclusive and diverse work environment. To achieve the objectives, a descriptive research with a mixed approach was carried out, using questionnaires applied to human resources leaders and interviews with managers of local companies. The analysis included secondary data on the regional labor market and the characteristics of employment opportunities in Santa Rosa, covering economic, social, and organizational conditions. The results show a shortage of qualified professionals, especially in operational and technical positions. The difficulty in attracting young talent stands out as a concern, while companies observe a positive trend in multi-ageism, valuing diversity in age and experience. However, challenges remain in retaining young people, who often seek better conditions and prospects outside the region. Skills such as emotional intelligence, resilience, adaptability, and innovation have been identified as essential for the future. The study concludes that, in order to strengthen the labor market in Santa Rosa, it is essential that companies invest in strategies for appreciation, training and innovation, aligned with the expectations of different age groups. Retention policies that meet the interests of professionals and encourage local permanence are fundamental. These efforts can contribute to a more resilient, competitive, and sustainable development labor market in the region, promoting both economic growth and social well-being.

Influence of Operator, Tool, Dental Loupes, and Tooth Position on Enamel Loss and Composite Remnants After Removal of Composite Attachments for Orthodontic Clear Aligners: An Experimental Study Using 3D Profilometry.

To assess the influence of operator, tool, dental loupes, and tooth position on enamel loss and composite remnants after removal of composite attachments (CA) for orthodontic clear aligners. Procedure duration was also analyzed. Eight maxillary resin dental arches with four natural teeth were placed in the right posterior sector in dental simulators, and CA was realized. The dental arches were randomly distributed according to three experimental factors: operator (junior, senior), tool (tungsten carbide bur and silicone polisher, only silicone polishers), and use of dental loupes. Dental arches were scanned with 3D profilometry before and after CA removal to measure enamel surface height variation (ESHV), particularly enamel loss in the CA area. Digital microscopy was used to detect composite remnants. The mean enamel loss was -22.7 ± 29.4 µm (range -132 to 0 µm). It was not significantly influenced by experimental factors or tooth position. Composite remnants were found in 34.4% of teeth, significantly more in senior than in junior operators (p = 0.038). They were more frequent with silicone polishers than with tungsten carbide burs (p = 0.0005) and were reduced using dental loupes (p = 0.0090). Junior operators worked faster than senior operators (p = 0.031), but the latter were quicker when using the dental loupes (p = 0.012). Aligner CA removal induces enamel damage or leaves composite remnants on its surface. The presence of composite remnants is influenced by the type of tool and can be reduced by using dental loupes, which also lowers working time.

Novel isothermal nucleic acid amplification method for detecting malaria parasites

Malaria, a parasitic disease caused by Plasmodium spp. and transmitted by Anopheles mosquitoes, remains a major global health issue, with an estimated 249 million cases and 608,000 deaths in 2022. Rapid and accurate diagnosis and treatment are crucial for malaria control and elimination. However, limited access to sensitive molecular tests means that microscopic examination and rapid diagnostic tests (RDT) are the most used methods in endemic areas, despite their lower diagnostic accuracy. Therefore, there is a need for developing sensitive, simple, accurate, and rapid diagnostic tools suitable for field conditions. Herein, we aimed to explore the potential of the enzymatic recombinase amplification assay (ERA® Technology) as a remote laboratory test by evaluating and validating the GENEYE® ERA Plasmodium detection kit in Brazilian endemic areas. A cross-sectional cohort study was conducted between June and August of 2023 in the Brazilian Amazon. The study enrolled 323 participants residing in three malaria-affected regions: Cruzeiro do Sul and Mâncio Lima (Acre State) and Guajará (Amazonas State). The participants were tested for malaria by microscopy, rapid diagnostic tests (RDT), nested PCR (nPCR), quantitative real-time PCR (qPCR), and ERA. The sensitivity, specificity, and predictive values were assessed using nPCR as a gold standard. Plasmodium prevalence was 21.7%, 18.8%, 19.2%, 21.7%, and 21.7% by nPCR, microscopy, RDT, qPCR, and ERA respectively. Using nPCR as the standard, qPCR, and ERA showed a sensitivity of 100%. In comparison, microscopy and RDT showed a sensitivity of 87.1% and 88.6%, a negative predictive value (NPV) of 96.56 and 96.93, and kappa values of 0.91 and 0.92, respectively. For Plasmodium falciparum, the sensitivity of qPCR and ERA was 100% while the sensitivity of microscopy and RDT was 96.9% and 93.7%, and the NPV was 99.66 and 99.32, respectively. For Plasmodium vivax, only ERA showed the same sensitivity of nPCR. The sensitivity, NPV, and kappa values were 78.85%, 97.27, and 0.87 for qPCR and microscopy, and 84.21%, 97.94, and 0.9 for RDT. The data presented here show that the GENEYE® ERA Plasmodium detection kit offers a promising alternative to traditional malaria diagnostic methods. Its high sensitivity, specificity, fast processing time, and operational simplicity position it as a valuable point-of-care diagnostic tool, particularly in resource-limited and remote malaria-endemic areas.Key points• GENEYE® ERA kit detects Plasmodium in under 25 min, no DNA purification needed.• The kit matches or exceeds the compared methods in sensitivity and specificity.• The kit is suitable for accurate testing in low-infrastructure, point-of-care settings.Graphical abstract

Minimal length scale in quantum mechanics from a deformation quantization perspective

Abstract We develop a deformation quantization approach to quantum mechanics that exhibits a nonzero minimal uncertainty in position through the modification of commutation relations for the operators of position and momentum. Deformation quantization is a method of quantizing a classical Hamiltonian system by suitably deforming the Poisson algebra of the system. The developed theory of deformation quantization is non-formal. An appropriate integral formula for the star-product is introduced, along with a suitable space of functions on which the star-product is well defined. A C*-algebra of observables and a space of states are constructed. Moreover, an operator representation in momentum space is presented. Finally, an example of states of maximal localization is given in terms of generalized Wigner functions.

Note on rotational properties of position operators of massless particles

Note on rotational properties of position operators of massless particles

Assessment of occupational injury and illness risks for the position of mineral water warehouse forklift operator

Optimizing the work accident and/or occupational disease prevention activity has as its starting point the assessment of occupational injury and disease risks. The notion of risk is defined in specialized literature by the probability with which an accident or an occupational illness occurs in a work process with a certain frequency and severity of consequences. The purpose of assessing the level of risk is to offer the possibility of knowing the real situation at each workplace, from the point of view of work security, in order to take the most suitable preventive measures for the given situation. The basis of the risk assessment principle consists in taking into account two parameters: the frequency of accidents and the severity of the maximum foreseeable consequence (principles also included in European standards)

Spin-Hall effect in topological materials: evaluating the proper spin current in systems with arbitrary degeneracies

The spin-Hall effect underpins some of the most active topics in modern physics, including spin torques and the inverse spin-Hall effect, yet it lacks a proper theoretical description. This makes it difficult to differentiate the SHE from other mechanisms, as well as differentiate band structure and disorder contributions. Here, by exploiting recent analytical breakthroughs in the understanding of the intrinsic spin-Hall effect, we devise a density functional theory method for evaluating the conserved (proper) spin current in a generic system. Spin non-conservation makes the conventional spin current physically meaningless, while the conserved spin current has been challenging to evaluate since it involves the position operator between Bloch bands. The novel method we introduce here can handle band structures with arbitrary degeneracies and incorporates all matrix elements of the position operator, including the notoriously challenging diagonal elements, which are associated with Fermi surface, group velocity, and dipolar effects but often diverge if not treated correctly. We apply this method to the most important classes of spin-Hall materials: topological insulators, 2D quantum spin-Hall insulators, non-collinear antiferromagnets, and strongly spin-orbit coupled metals. We demonstrate that the torque dipole systematically suppresses contributions to the conventional spin current such that, the proper spin current is generally smaller in magnitude and often has a different sign. Remarkably, its energy-dependence is relatively flat and featureless, and its magnitude is comparable in all classes of materials studied. These findings will guide the experiment in characterizing charge-to-spin interconversion in spintronic and orbitronic devices. We also discuss briefly a potential generalization of the method to calculate extrinsic spin currents generated by disorder scattering.

Shifting perceptions of informal operators in the service and value chains: A retrospective of 40 years of observation and advocacy for informal recyclers and waste service providers, through the eyes of five global participant-researchers.

This article offers a reflective retrospective of the literature and practice on the informal waste and recycling sector. The authors have joined to share our experience and knowledge on the interface between the formal solid waste sector and informal recyclers and operators. Together, we discuss where this discourse has come from, where it is now, and where we, as practitioners, think it is going. We share our understanding of the waste and recycling sectors and how informality within them functions. The retrospective covers nearly 40 years of research, practice, advocacy, action, writing and intervention. The main storyline is how the public and private solid waste authorities and service providers relate to informal operators in both recycling ('the (private) value chains') and waste management ('the (public) service chain'). The recurring theme is how engaged scholarship and practice have interacted with, modified and improved the position of informal operators and workers and contributed to positive outcomes in both service and value chains. Throughout the period covered by this retrospective, opinions and framing on all sides have shifted substantially through the years, whereas the economic activities of informal recyclers and informal waste collection service providers have remained largely unchanged. Although we refer to both scientific and operational documents, we do not have the ambition to produce a scientific paper. Rather, we follow other authors of the special issue in referring to ourselves as involved witnesses who share a commitment to improving waste and recycling practices at the boundary of formal and informal systems.

Contralateral knee-flexion prone split-leg percutaneous nephrolithotomy: A versatile technique

ObjectiveThis study developed a novel technique for performing percutaneous nephrolithotomy (PCNL) in the knee-flexion (KF)-prone split-leg (PSL) position; this technique aimed to address the shortcomings of the traditional prone (TP) position and PSL. The study evaluated the safety, advantages, and feasibility of KF-PSL compared to TP. MethodsA novel technique was developed based on the common PSL. A retrospective analysis was conducted on the data of 276 patients who underwent PCNL in either the KF-PSL or TP position between January 2022 and June 2023. Demographic and perioperative clinical data of the KF-PSL and TP groups were reviewed and compared. ResultsA total of 276 patients were divided into two groups based on the operative position. The preoperative parameters of the two groups did not differ significantly. The overall mean stone size was 40.03 (standard deviation [SD] 23.89] mm in maximum diameter. Significant differences were found in both the mean operative time (80.9 [SD 47.2]) min in KF-PSL vs. 107.3 [SD 57.7] min in TP, p<0.001) and stone-free rates (72.7% in KF-PSL vs. 61.3% in TP, p=0.046). Braden scale scores of the two groups did not differ significantly (p=0.115). No significant difference was observed between the groups in the total complication rate (p=0.570). ConclusionThe KF-PSL is a promising modified position for PCNL that allows for a shorter operative time, a higher stone-free rate, and a more simplified surgical procedure compared to TP position without compromising outcomes. It is more convenient for combined therapy, allowing an access to the entire urinary tract without the need for position changes.

A Data-Driven Bayesian Koopman Learning Method for Modeling Hysteresis Dynamics.

Exploring the mechanism of hysteresis dynamics may facilitate the analysis and controller design to alleviate detrimental effects. Conventional models, such as the Bouc-Wen and Preisach models consist of complicated nonlinear structures, limiting the applications of hysteresis systems for high-speed and high-precision positioning, detection, execution, and other operations. In this article, a Bayesian Koopman (B-Koopman) learning algorithm is therefore developed to characterize hysteresis dynamics. Essentially, the proposed scheme establishes a simplified linear representation with time delay for hysteresis dynamics, where the properties of the original nonlinear system are preserved. Furthermore, model parameters are optimized via sparse Bayesian learning together with an iterative strategy, which simplifies the identification procedure and reduces modeling errors. Extensive experimental results on piezoelectric positioning are elaborated to substantiate the effectiveness and superiority of the proposed B-Koopman algorithm for learning hysteresis dynamics.

The Determinants of Fiscal Health: An Exploration of Municipalities in Brazil

ABSTRACT The public administration literature has largely focused on local government fiscal health, mostly using data from the U.S. However, how well does this research hold up in other contexts? Using data from 5,524 municipalities from 2013 to 2021, we explore determinants of financial conditions, employing two financial indicators tailored to Brazil’s context: operational positioning and immediate liquidity. Our findings reveal that municipalities with experienced mayors and greater fiscal autonomy tend to have more favorable fiscal conditions. While local characteristics such as per capita income, population size, and density occasionally played a role, they were not consistently the most significant factor.

Analysis of poor work postures during morning care operations of intensive care unit nurses: a field research

BackgroundPoor working postures in morning care operations contribute significantly to work-related muscle fatigue and low back pain among ICU (Intensive Care Unit, ICU) nurses. However,there are few field studies on the relationship between Poor working postures and work-related muscle fatigue, low back pain among ICU nurses.ObjectiveThis study aims to assess the frequency and degree of posture hazards associated with poor working postures during morning care operations of ICU nurses.MethodsTwo ICUs in a Grade-A tertiary hospital in Hunan Province were randomly selected for the field study in May–June 2021 research. The image data of the participating nurses’ morning care work postures were collected by observation method and image recording method, and the postural hazard level was assessed by the two-person interpretation method of the work posture analysis system. The mean and standard deviation, frequency and percentage were used for the basic statistical description, and the general linear model multivariate Hotelling’s T2 test was used to calculate the Hotelling’s T2 and F statistics to explore the pattern of change in the postural hazard score curves.ResultsA total of 45 nurses were observed during morning care operations, resulting in 47.8 h of video data and 34,428 effective static operation posture pictures. Among these pictures, 21,166 (61.5%) depicted poor working postures. Nurses spent up to 7 min and 30 s maintaining a challenging posture during oral care, with the highest postural hazard score (M = 2.2, SD = 0.3) observed during defecation care. Each patient requires a total of 25–30 min of oral care per day.The Hotelling’s T2 test indicated that the change curve of the postural hazard score in each step revealed the largest second-order F value, F = 52.931, P < 0.001.DiscussionICU nurses frequently adopt poor working postures during morning care operations. Further research should focus on optimizing safe working postures to prevent or minimise detrimental occupational hazards resulting from poor working postures.Research on occupational low back pain among ICU nurses can help them work more efficiently, and thereby improving their nursing level.

Evaluación de las Prácticas Profesionales Supervisadas: Análisis de Informes y su Relevancia en la Educación Universitaria

The objective is to present an overview of the experience of university students from a private university in Paraguay during their curricular internships. It was based on a qualitative, transversal, exploratory and descriptive approach. 13 reports of student internships from a private university in Paraguay were analyzed for convenience, 2024. Reports of student internships that have been approved by the corresponding coordination of the Audiovisual Communication career, and from the year 2023, were included. Data collection was carried out through a checklist with four components and 13 items. The analysis revealed that 62% of the interns were women. All the companies where they carried out their internships belong to the services sector, with 77% private capital. 92% of the reports clearly presented the mission and organizational structure. All students held operational positions related to their career and 69% highlighted general knowledge of the area as a significant contribution to their development. It is concluded that professional practices are developed effectively, with the support of coordinators and tutors, highlighting the opportunities and their contribution to professional training.