Sign Change Research Articles

Imaging of human parafoveal area with large field of view in adaptive optics line scanning ophthalmoscope

The parafoveal area, with its high concentration of photoreceptors and fine retinal capillaries, is crucial for central vision and often exhibits early signs of pathological changes. The current adaptive optics scanning laser ophthalmoscope (AOSLO) provides an excellent tool to acquire accurate and detailed information about the parafoveal area with cellular resolution. However, limited by the scanning speed of two-dimensional scanning, the field of view (FOV) in the AOSLO system was usually less than or equal to 2∘, and the stitching for the parafoveal area required dozens of images, which was time-consuming and laborious. Unfortunately, almost half of patients are unable to obtain stitched images because of their poor fixation. To solve this problem, we integrate AO technology with the line-scan imaging method to build an adaptive optics line scanning ophthalmoscope (AOLSO) system with a larger FOV. In the AOLSO, afocal spherical mirrors in pairs are nonplanar arranged and the distance and angle between optical elements are optimized to minimize the aberrations, two cylinder lenses are orthogonally placed before the imaging sensor to stretch the point spread function (PSF) for sufficiently digitizing light energy. Captured human retinal images show the whole parafoveal area with [Formula: see text] FOV, 60[Formula: see text]Hz frame rate and cellular resolutions. Take advantage of the 5∘ FOV of the AOLSO, only 9 frames of the retina are captured with several minutes to stitch a montage image with an FOV of [Formula: see text], in which photoreceptor counting is performed within approximately 5∘ eccentricity. The AOLSO system not only provides cellular resolution but also has the capability to capture the parafoveal region in a single frame, which offers great potential for noninvasive studying of the parafoveal area.

Average estimates and sign change of Fourier coefficients of cusp forms at integers represented by binary quadratic form of fixed discriminant

Average estimates and sign change of Fourier coefficients of cusp forms at integers represented by binary quadratic form of fixed discriminant

Application of a hybrid approach to the removal of large esophageal schwannoma

Introduction. Esophageal schwannoma is a rare spindle cell tumor derived from Schwann cells. To date, only 17 cases of esophageal schwannoma have been reported, with most of them occurring in women over the age of 50 years. Surgical interventions using open (cervical approach, extirpation of the esophagus with simultaneous plasty of the gastric tube) and thoracoscopic approaches have long been considered standard methods of treating patients with nonepithelial tumors of the esophagus, but currently minimally invasive endoscopic interventions are widely used. Clinical case. The patient, 64 years old, was treated at the Vishnevsky National Research Medical Center for Surgery for a large schwannoma of the esophagus. Results. This article presents a rare clinical observation - removal of a large schwannoma of the esophagus using a hybrid approach. During a control endoscopic examination 4 months after surgery, no signs of residual tumor fragments, narrowing or pathological changes in the mucosa were found in the area of the previously performed dissection. Conclusion. The use of a hybrid approach for removing a large non-epithelial tumor of the esophagus using endoscopic dissection in the submucosal layer and subsequent extraction through the cervical approach made it possible to perform organ-saving surgery, minimize the risks of possible intraoperative and postoperative complications, thereby leading to a good clinical and functional result.

Polarization-driven band topology evolution in twisted MoTe2 and WSe2

Motivated by recent experimental observations of opposite Chern numbers in R-type twisted MoTe2 and WSe2 homobilayers, we perform large-scale density-functional-theory calculations with machine learning force fields to investigate moiré band topology across a range of twist angles in both materials. We find that the Chern numbers of the moiré frontier bands change sign as a function of twist angle, and this change is driven by the competition between moiré ferroelectricity and piezoelectricity. Our large-scale calculations, enabled by machine learning methods, reveal crucial insights into interactions across different scales in twisted bilayer systems. The interplay between atomic-level relaxation effects and moiré-scale electrostatic potential variation opens new avenues for the design of intertwined topological and correlated states, including the possibility of mimicking higher Landau level physics in the absence of magnetic field.

Multiple signs of ecosystem change in the zooplankton community of a large temperate lake

Large lakes, such as Lake Simcoe, Ontario, Canada, are undergoing significant change due to local and global stressors. Uni- and multivariate analyses of Lake Simcoe's zooplankton community from 1986 to 2012 indicated multiple events of ecosystem change that were synchronous across three lake stations . In the mid-1990s, shifts in zooplankton species abundance and richness, and total cladoceran body size were strongly correlated with the invasion of the zooplanktivore, Bythotrephes cederstroemii. In the early 2000s, additional shifts in zooplankton abundance, as well as copepod body size, coincided with increased water clarity (linked to filter feeding by the invader Dreissena polymorpha) and hypolimnetic water temperature. Further community changes occurred in the 2000s when Bythotrephes declined and many vulnerable cladoceran species recovered. However, the Lake Simcoe community did not fully return to its pre-invasion state as the cold-water herbivores, Daphnia longiremis and Daphnia pulicaria, remained absent. The Lake Simcoe zooplankton community illustrates ongoing ecosystem change that propagated throughout the lake food web and may be reflected in other lakes experiencing global stressors of climate change and species invasions.

AN EFFICIENT DATA SECURITY IN MEDICAL REPORT USING BLOCKCHAIN TECHNOLOGY

The health care services industry is always showing signs of change and supporting new advancements and advances. One of the predominant requirements in today’s health care systems is to protect the patient's medical report against potential attackers. Hence, it is basic to have secure information that can just approve people can get to the patient's medical report. So, it has proposed Block chain technology as a disbursed approach to grant security in accessing the medical report of a patient. It’s composed of three phases: Authentication, Encryption and Data Retrieval using Block Chain Technology. For authentication –Quantum Cryptography. Key Words: Block chain, Medical Report, Data Accessibility, Security, Encryption, Data Retrieval.

Nonlinear Stability of Equilibria in Hamiltonian Systems with Multiple Resonances without Interactions

In this work, we advance in the study of the Lyapunov stability and instability of equilibrium solutions of Hamiltonian flows. More precisely, we study the nonlinear stability in the Lyapunov sense of equilibrium solutions in autonomous Hamiltonian systems with n-degrees of freedom, assuming the existence of two resonance vectors k1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{k}^1$$\\end{document} and k2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{k}^2$$\\end{document} without interaction (|k1|≤|k2|\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|\ extbf{k}^1|\\le |\ extbf{k}^2|$$\\end{document}). We provide conditions to obtain a type of formal stability, called Lie stability. In particular, we need to normalize the Hamiltonian function to any arbitrary order, and our results take into account the sign of the components of the resonance vectors. Subsequently, we guarantee some sufficient conditions to obtain exponential stability in the sense of Nekhoroshev for Lie stable systems. In addition, we give sufficient conditions for the instability in the Lyapunov sense of the full system. For this, it is necessary to normalize the Hamiltonian function to an adequate order, and assuming that the components of at least one resonance vector change of sign.

Climate change as observed through the IMS radionuclide station in Spitzbergen

The International Monitoring System (IMS), installed and maintained by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) with the support of States Signatories, is a global system of monitoring stations based on four complementary technologies: seismic, hydroacoustic, infrasound and radionuclide. One of the IMS radionuclide stations is located in Spitzbergen, the largest island of the Norwegian Svalbard Archipelago, which borders the Barents Sea and the Northern Atlantic Ocean. It has been demonstrated that signs of climate change are particularly noticeable in that region. As many other radionuclides observed in environmental measurements, 212Pb is always observed at IMS stations, in varying quantities. This is also the case for the IMS station RN49, Spitzbergen, where it can be demonstrated that the average concentration of the measured lead 212Pb increases. This is observable specifically October through December. This paper demonstrates the asset of IMS data to study climate change effects. Our conclusions are supported by global temperature anomaly data from NOAA’s Global Surface Temperature Analysis, covering the period 1850 to 2023.

Functional renormalization group study of thermodynamic geometry around the phase transition of quantum chromodynamics

We investigate the thermodynamic geometry of the quark-meson model at finite temperature, T, and quark number chemical potential, μ. We extend previous works by the inclusion of fluctuations exploiting the functional renormalization group approach. We use recent developments to recast the flow equation into the form of an advection-diffusion equation. We adopt the local potential approximation for the effective average action. We focus on the thermodynamic curvature, R, in the (μ,T) plane, in proximity of the chiral crossover, up to the critical point of the phase diagram. We find that the inclusion of fluctuations results in a smoother behavior of R near the chiral crossover. Moreover, for small μ, R remains negative, signaling the fact that bosonic fluctuations reduce the capability of the system to completely overcome the fermionic statistical repulsion of the quarks. We investigate in more detail the small μ region by analyzing a system in which we artificially lower the pion mass, thus approaching the chiral limit in which the crossover is actually a second order phase transition. On the other hand, as μ is increased and the critical point is approached, we find that R is enhanced and a sign change occurs, in agreement with mean field studies. Hence, we completely support the picture that R is sensitive to a crossover and a phase transition, and provides information about the effective behavior of the system at the phase transition. Published by the American Physical Society 2024

Spin-orbit-splitting-driven nonlinear Hall effect in NbIrTe4

The Berry curvature dipole (BCD) serves as a one of the fundamental contributors to emergence of the nonlinear Hall effect (NLHE). Despite intense interest due to its potential for new technologies reaching beyond the quantum efficiency limit, the interplay between BCD and NLHE has been barely understood yet in the absence of a systematic study on the electronic band structure. Here, we report NLHE realized in NbIrTe4 that persists above room temperature coupled with a sign change in the Hall conductivity at 150 K. First-principles calculations combined with angle-resolved photoemission spectroscopy (ARPES) measurements show that BCD tuned by the partial occupancy of spin-orbit split bands via temperature is responsible for the temperature-dependent NLHE. Our findings highlight the correlation between BCD and the electronic band structure, providing a viable route to create and engineer the non-trivial Hall effect by tuning the geometric properties of quasiparticles in transition-metal chalcogen compounds.

The stock market reaction to political and economic changes: the Spanish case

As other European countries, Spain has experienced a turmoil in which new political parties emerged with force after the global financial crisis in 2008. In this context, we analyze whether the empirical implications of the opportunistic and partisan theories, as well as the Uncertain Information Hypothesis, are met in the Spanish stock market, considering the size and the industry of the companies. The horizon of our study takes into account the seven general elections, 24 regional elections and 4 European elections held from 2002 to 2019, period in which Spain is fully integrated in the economic and monetary union and under the macroeconomic imbalance procedure. Our results do not support the opportunistic and partisan theories, or the Uncertain Information Hypothesis. Our evidence suggests that the short-term negative market reaction to the general elections is linked to the uncertainty with a change in the political sign of the incumbent. Besides, it is not related to size or industry characteristics.

Developing a simple and efficient modeling solution for predicting key phenological stages of table grapes in a non-traditional viticulture zone in south Asia.

Phenological shifts are one of the most visible signs of climatic variability and change in the biosphere. However, modeling plant phenological responses has always been a key challenge due to climatic variability and plant adaptation. Grapevine is a phenologically sensitive crop and, thus, its developmental stages are affected by the increase in temperature. The goal of this study was to develop a temperature-based grapevine phenology model (GPM) for predicting key developmental stages for different table grape cultivars for a non-traditional viticulture zone in south Asia. Experiments were conducted in two vineyards at two locations (Chakwal and Islamabad) in the Pothawar region of Pakistan during the 2019 and 2020 growing seasons for four cultivars including Perlette, King's Ruby, Sugraone and NARC Black. Detailed phenological observations were obtained starting in January until harvest of the grapes. The Mitscherlich monomolecular equation was used to develop the phenology model for table grapes. There was a strong non-linear correlation between the Eichhorn and Lorenz phenological (ELP) scale and growing degree days (GDD) for all cultivars with coefficient of determinations (R2) ranging from 0.90 to 0.94. The results for model development indicated that GPM was able to predict phenological stages with high skill scores, i.e., a root mean square (RMSE) of 2.14 to 2.78 and mean absolute error (MAE) of 1.86 to 2.26 days. The prediction variability of the model for the onset timings of phenological stages was up to 3 days. The results also reveal that the phenology model based on GDD approach provides an efficient planning tool for viticulture industry in different grape growing regions. The proposed methodology, being a simpler one, can be easily applied to other regions and cultivars as a predictor for grapevine phenology.

Precipitation patterns and their variability in the southern region of Brazil

Climate change is a long-term transformation of climate patterns, which can be natural or anthropogenic. Signs of climate change can manifest themselves in different ways: through the occurrence of extreme events, rising ocean levels, melting glaciers, among others. Negative impacts are produced by climate change and are one of humanity's biggest concerns, since its effects reach the entire planet with different consequences. Considering the need for actions aimed at contributing to the process of mitigating climate change, the importance of knowing changes in regional climate patterns is emphasized. This study aims to analyze changes in precipitation patterns over time in the southern region of Brazil, including variability, trends, anomalies, droughts and excess rainfall. Daily precipitation data from 1961 to 2020 were used, collected at 15 meteorological stations in the region. Various statistical analyzes were carried out, such as averages, maximum and minimum values, seasonal and annual anomalies, frequency distribution, Mann-Kendall trend tests and the Normalized Precipitation Index (SPI). The results indicate that climate change trends are positive in terms of increasing rainfall volumes, altering rainfall dispersion patterns (volume). In other words, rainfall is more irregular in terms of distribution throughout the seasons. The big highlight was Florianópolis -SC, which during the summer had the highest volume of rain among the meteorological stations studied.

Risk perceptions and experience in child protection decision-making: A comparative study of student social workers in Wales and Aotearoa New Zealand

Decision making in child protection is the product of interacting factors between workers, organizations, families, and macro social structures. Individual perceptions of risk, safety, and harm, as one piece of this complex puzzle, are important to understand. This article reports on a comparative study of social work students in two countries: Wales and Aotearoa New Zealand. Using a mixed methods survey and a staged vignette (in which the situation becomes progressively more serious), we found there were similarities between respondents from the two countries in their perceptions of risk, safety and harm, and their reasoning processes. Beneath this broad consensus, respondents from Wales rated the level of harm to the children lower at earlier stages but were more likely to say the case should meet the threshold for statutory intervention. Risk-averse respondents were more likely to conclude the children experienced serious harm and also that the case should meet the threshold for statutory intervention. These differences largely disappeared by the concluding stage. Qualitative analysis shows that the reasoning processes used to explain risk, safety, and plan goals were similar between the two countries. Some nuanced differences emerged in relation to a risk-averse group fromAotearoa New Zealandemphasizing the importance of continuing engagement with professional services as a sign of change. Implications are discussed, particularly for workforce development and the needs of newly qualified social workers.

Intrinsic negative Poisson’s ratio of the monolayer semiconductor β- TeO2

Monolayer semiconductors with unique mechanical responses are promising candidates for novel electromechanical applications. Here, through first-principles calculations, we discover that the monolayer β- TeO2 , a high-mobility p-type and environmentally stable 2D semiconductor, exhibits an unusual out-of-plane negative Poisson’s ratio (NPR) when a uniaxial strain is applied along the zigzag direction. The NPR originates from the unique six-sublayer puckered structure and hinge-like Te–O bonds in the 2D β- TeO2 . We further propose that the sign of the Raman frequency change under uniaxial tensile strain could assist in determining the lattice orientation of monolayer β- TeO2 , which facilitates the experimental study of the NPR. Our results is expected to motivate further experimental and theoretical studies of the rich physical and mechanical properties of monolayer β-TeO2.

Thermodynamic information geometry of criticality, fluctuation anomaly and hyperscaling breakdown in the spin-3/2 chain

Equilibrium state space geometry is worked out for the exactly solved one-dimensional spin-3/2 lattice with a Blume–Emery–Griffiths (BEG) Hamiltonian as well as a more general one with a non-zero field coupled to the octopole moments. The phase behaviour of the spin-3/2 chain is revisited and novel observations of anomaly in the hyperscaling relation and in the decay of fluctuations are reported for the first time. Using the method of constrained fluctuations developed earlier in Sahay (2017); Sanwari and Sahay (2022) three appropriate state space sectional curvatures and a 3d curvature are shown to separately encode dipolar, quadrupolar and octopolar correlations both near and away from pseudo-criticality. In all observations of hyperscaling breakdown the 3d scalar curvature is found to encode the correlation length while the relevant sectional curvature equals the inverse of singular free energy. For parameter values where the order parameter fluctuation anomalously decays despite a divergence in its correlation length the relevant scalar curvature undergoes a sign change to positive values, signalling a possible change in the nature of the underlying statistical interactions.

Framework to elicit consent from lightly sedated mechanically ventilated intensive care patients in nursing practice.

The study aimed to ascertain a framework of nursing practices to elicit consent from lightly sedated ventilated patients. Study participants were nurses working in intensive care and critical care wards, whose observations and semi-structured interviews were assessed using a modified grounded theory approach. A total of 15 concepts were generated, from which three categories and three subcategories were generated. Category 1: Nurses taking the lead in providing assistance by sharing signs of change while continuing the invasive treatment, working to maintain the patient's life, alleviation of pain, promotion of awareness of the current situation, and acclimating them to the treatment environment as the basis for building a relationship between patients and nurses. Category 2: Searching for points of agreement and reaching a compromise involves the nurse drawing out the patient's thoughts, hopes, and expectations, and transforming the relationship into a patient-centered one by sharing goals with the patient in order to achieve them. Category 3: Organizing collaboration within care supported the patient's ability to move safely while maintaining the patient's pace to achieve shared goals, and guided the patient's independent actions. Even when patients recover from an acute life-threatening situation, their physical sensations remain vague and their functional decline continues. Rather than simply eliciting consent from patients, the structure of nursing practice to elicit such response from patients involves drawing out the patient's thoughts, hopes, and expectations, as well as guiding the patient toward goals that they have created together with the nurse and utilizing the patient's strengths to achieve these goals.

Diffusiophoretic Transport of Charged Colloids in Ionic Surfactant Gradients Entirely below versus Entirely above the Critical Micelle Concentration.

When placed in an ionic surfactant gradient, charged colloids will undergo diffusiophoresis at a velocity, uDP = MDP∇ ln S, where MDP is the diffusiophoretic mobility and S is the surfactant concentration. The diffusiophoretic mobility depends in part on the charges and diffusivities of the surfactants and their counterions. Since micellization decreases surfactant diffusivity and alters charge distributions in a surfactant solution, MDP of charged colloids in ionic surfactant gradients may differ significantly when surfactant concentrations are above or below the critical micelle concentration (CMC). The role of micelles in driving diffusiophoresis is unclear, and a previously published model that accounts for micellization suggests the possibility of a change in the sign of MDP above the CMC [Warren, P. B.; . Soft Matter 2019, 15, 278-288]. In the current study, microfluidic channels were used to measure the transport of negatively charged polystyrene colloids in sodium dodecyl sulfate (SDS) surfactant gradients established at SDS concentrations that are either fully above or fully below the CMC. Interpretation of diffusiophoresis was aided by measurements of the colloid electrophoretic mobility as a function of SDS concentration. A numerical transport model incorporating the prior diffusiophoretic mobility model for ionic surfactant gradients was implemented to elucidate signatures of positive and negative diffusiophoretic mobilities and compare with experiments. The theoretically predicted sign of the diffusiophoretic mobility below the CMC was determined to be particularly sensitive to uncertainty in colloid and surfactant properties, while above the CMC, the mobility was consistently predicted to be positive in the SDS concentration range considered in the experiments conducted here. In contrast, experiments only showed signatures of a negative diffusiophoretic mobility for these negatively charged colloids with no change of sign. Colloid diffusiophoretic transport measured in micellar solutions was more extensive than that below the CMC with the same ∇ ln S.

Entangling Interactions Between Artificial Atoms Mediated by a Multimode Left-Handed Superconducting Ring Resonator

Superconducting metamaterial transmission lines implemented with lumped circuit elements can exhibit left-handed dispersion, where the group and phase velocity have opposite sign, in a frequency range relevant for superconducting artificial atoms. Forming such a metamaterial transmission line into a ring and coupling it to qubits at different points around the ring results in a multimode bus resonator with a compact footprint. Using flux-tunable qubits, we characterize and theoretically model the variation in the coupling strength between the two qubits and each of the ring-resonator modes. Although the qubits have negligible direct coupling between them, their interactions with the multimode ring resonator result in both a transverse exchange coupling and a higher-order ZZ interaction between the qubits. As we vary the detuning between the qubits and their frequency relative to the ring-resonator modes, we observe significant variations in both of these interqubit interactions, including zero crossings and changes of sign. The ability to modulate interaction terms such as the ZZ scale between zero and large values for small changes in qubit frequency provides a promising pathway for implementing entangling gates in a system capable of hosting many qubits. Published by the American Physical Society 2024

A modified orthotopic left lung transplantation model in rats

To enhance the operability of the rat orthotopic left lung transplantation model, we implemented several improvements and meticulously detailed the procedure. One hundred and thirty-one healthy male Sprague Dawley rats, weighing between 250 and 300 g, were utilized, with 64 serving as donors, 64 as recipients, and 3 as sham controls. We employed a modified three-cuff technique for the orthotopic left lung transplantation. Notably, our modified perfusion method could prevent donor lung edema, while waist-shaped cuffs minimized suture slippage during anastomosis. Additionally, positioning the recipient rat in a slightly left-elevated supine position during anastomosis reduced tension on the lung hilum, thus mitigating the risk of vascular laceration. The introduction of a unique two-person anastomosis technique significantly reduced operation time and substantially improved success rates. Furthermore, maximizing inflation of donor lungs both during preservation and surgery minimized the occurrence of postoperative atelectasis. Various other procedural refinements contributed to the enhanced operability of our model. Sixty-four rat orthotopic left lung transplantations were performed with only one surgical failure observed. The acquisition time for donor lungs averaged (19 ± 4) minutes, while (11 ± 1) minutes were allocated for donor lung hilum anatomy and cuff installation. Recipient thoracotomy and left lung hilar anatomy before anastomosis required (24 ± 8) minutes, with anastomosis itself taking (31 ± 6) minutes. Remarkably, the survival rate at the 4-h postoperative mark stood at 96.7 %. Even six months post-operation, transplanted left rat lungs continued to exhibit proper inflation and contraction rhythms, displaying signs of chronic pathological changes. In summary, our modified rat model of orthotopic left lung transplantation demonstrates robust operability, significantly reducing surgical duration, improving operation success rates, and enhancing postoperative survival rates. Furthermore, its long-term survival capacity enables the simulation of acute and chronic disease processes following lung transplantation.