Changes In Field Research Articles

Analysis of Intraoperative Visual Evoked Potentials for Inclusion of Unstable Electroretinograms

Purpose: The objectives of the study were to evaluate the validity of intraoperative flash visual evoked potentials (VEPs) when electroretinograms (ERGs) were unstable, to compare white versus red light-emitting diodes, and to assess the impact of luminance on ERG variability. Methods: Thirty patients were included (Inomed system; pre- and postoperative visual fields). Possible changes in visual fields were assessed with mean defects in perimetry. The receiver operating characteristic (ROC) curves of normalized VEPs and of normalized and corrected VEPs with ERGs were compared. Results: Thirty-two eyes could be analyzed in 20 patients (mainly gliomas and meningiomas): 2 had a severe defect in their visual field, and 6 had a mild defect. The receiver operating characteristic curve indicated (1) normalized and corrected VEPs with ERGs were more reliable than normalized VEPs only (P < 0.03) and (2) an alarm threshold of 80% of normalized and corrected VEPs. No significant difference in variability of ERGs was found with white or red light-emitting diodes with this system. Increased luminance improved stability of ERGs (P < 0.05). Conclusions: Normalization and correction of VEPs with ERGs improved the validity of VEPs and indicated a 20% decrease as alarm criterion. This normalization and correction with peripheral excitation could be generalized to improve the reliability of neuromonitoring.

Effect of settling vortex of coal slime flocs with different sizes on the settlement of microfine particles

This article explores the flow field changes and micro vortex formation mechanisms caused by coagulation and sedimentation of coal slurry flocs of different sizes. The collision adhesion rate, motion trajectory and force analysis of fine particles under micro vortex disturbance. Particle image velocimetry (PIV) and high-speed camera were used to capture deposition process of coal slime flocs, the changes of flow field and fine particles were analyzed by numerical simulation. The smaller flocs form a single vortex ane larger flocs show periodic vortex shedding, resulting in increase fluid velocity and larger interference area. The collision adhesion rate of fine particles in the 3.4 mm floc settling disturbance area is the largest, 9.45 %;Particles<0.3 mm are easily sucked into vortices, while particles>0.3 mm are disturbed by vortices and change their motion trajectory towards the vortex center. It is mainly affected by gravity, pressure gradient force, flow field resistance, and centrifugal force.

Electro-capacitive cancer therapy using wearable electric field detector: a review

Electro-capacitive cancer therapy (ECCT), a less invasive and more targeted approach using wearable electric field detectors, is revolutionizing cancer therapy, a complex process involving traditional methods like surgery, chemotherapy, and radiation. The review aims to investigate the safety and efficacy of electric field exposure in vital organs, particularly in cancer therapy, to improve medical advancements. It will investigate the impact on cytokines and insulation integrity, as well as contribute to improving diagnostic techniques and safety measures in medical and engineering fields. Wearable electric field detectors have revolutionized cancer therapy by offering a non-invasive and personalized approach to treatment. These devices, such as smart caps or patches, measure changes in electric fields by detecting capacitance alterations. Their lightweight, comfortable, and easy to-wear nature allows for real-time monitoring, providing valuable data for personalized treatment plans. The portability of wearable detectors allows for long-term surveillance outside clinical settings, increasing therapy efficacy. The ability to collect data over extended periods provides a comprehensive view of electric field dynamics, aiding researchers in understanding tumor growth and progression. Technology advancements in electro-capacitive therapy, including wearable devices, have revolutionized cancer treatment by adjusting electric field intensity in real-time, enhancing personalized medicine, and improving treatment outcomes and patient quality of life.

Development of a horizontal seepage test system of constructed wetland and research on the seepage characteristics based on micro-pollution water

Horizontal subsurface flow constructed wetlands (HSFCW) were widely used as an effective biotechnology for wastewater treatment. However, clogging of the substrate bed was a key factor restricting its application. In this study, a horizontal seepage test system was independently developed, which was used to reveal the development trends of hydraulic resistance in HSFCW, as well as changes in permeability coefficients with time. The relationship between the average permeability coefficient and purification effect was further analyzed. The results showed that the new test system has proved the law of resistance development in HSFCW. The distribution characteristics of the isobaric surface indicate that the blockage of the HSFCW gradually spreads from the lower part to the lower part. The seepage resistance of homogeneous subbed in HSFCW was mainly concentrated in the front end. The growth rate of hydraulic loss in the core zone ranged from 0.685 to 19.515 cm·month−1, the growth rate in the transition zone ranged from 0.223 to 0.695 cm·month−1, and little change occurred in the safety zone. At the end of the HSFCW operation, the widths of the core, transition, and safety zones account for approximately 20–30 %, 50–70 %, and 10–20 % of the entire wetland length, respectively. Meanwhile, the SS removal rate stabilized at over 92 %, when the average permeability coefficient reached 41.45 m·d−1. The removal rate of COD and TN was higher when the average permeability coefficient is between 59.45 and 41.45 m·d−1 and 27.08–59.45 m·d−1, respectively. This study provided a horizontal testing method to accurately understand the changes in the seepage field in HSFCW.

Performance sensitivity analysis and aerodynamic optimization of compressor cascades by a turbulence adjoint method

Sensitivity, which is useful for evaluating the contributions of input variations to output changes, favors designers exploiting the most sensitive design parameters and completing design optimization in aerospace. This study introduces the turbulence adjoint method due to its low computational cost in calculating sensitivities with high accuracy and then solves the adjoint partial differential equations with respect to both the Reynolds-averaged Navier–Stokes and turbulence model equations with the assistance of an automatic differentiation tool. By utilizing the turbulence adjoint method, the sensitivities of aerodynamic performance to the blade profile modifications of two-dimensional and three-dimensional compressor cascades are calculated, allowing for the investigations of the impact of geometric variations on the changes in the flow field. Ultimately, aerodynamic optimization of the compressor cascades is conducted. After optimization, the adiabatic efficiency of the two-dimensional cascade increases by 3.11%, and it increases by 1.15% for the three-dimensional cascade. The variations in flow fields of both the original and optimized cascades are illustrated to discover the origins of performance improvements. The changes in blade profile are almost consistent with those forecasted from sensitivity analysis, demonstrating the potential superiority of the adjoint method for aerodynamic design.

Different Effects of a Super Storm on Atmospheric Electric Fields at Different Latitudes

Geomagnetic storms have a significant impact on Earth’s magnetosphere and ionosphere, as well as on the global atmospheric circuit. This study focuses on investigating the anomalous variations in the vertical atmospheric electric field at eight mid-latitude and low-latitude stations during a mega-geomagnetic storm on 24 April 2023. The majority of stations observed vertical atmospheric electric field increases, while only three nearby stations exhibited vertical atmospheric electric field decreases. The analysis revealed that vertical atmospheric electric field changes ranged from 19 to 370 V/m, and the time differences between extreme vertical atmospheric electric field values and the minimum Dst value ranged from 0 to 5.3 h. Other response patterns to this super magnetic storm at different latitudes are summarized, and the physical mechanisms of different effects of magnetic storms on the electric fields of stations at different latitudes are also discussed.

Identifying Changes and Their Drivers in Paddy Fields of Northeast China: Past and Future

Northeast China plays a crucial role as a major grain-producing region, and attention to its land use and land cover changes (LUCC), especially farmland changes, are crucial to ensure food security and promote sustainable development. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) data and a decision tree model, land types, especially those of paddy fields in Northeast China from 2000 to 2020, were extracted, and the spatiotemporal changes in paddy fields and their drivers were analyzed. The development trends of paddy fields under different future scenarios were explored alongside the Coupled Model Intercomparison Project Phase 6 (CMIP6) data. The findings revealed that the kappa coefficients of land use classification from 2000 to 2020 reached 0.761–0.825, with an overall accuracy of 80.5–87.3%. The proposed land classification method can be used for long-term paddy field monitoring in Northeast China. The LUCC in Northeast China is dominated by the expansion of paddy fields. The centroids of paddy fields gradually shifted toward the northeast by a distance of 292 km, with climate warming being the main reason for the shift. Under various climate scenarios, the temperature in Northeast China and its surrounding regions is projected to rise. Each scenario is anticipated to meet the temperature conditions necessary for the northeastward expansion of paddy fields. This study provides support for ensuring sustainable agricultural development in Northeast China.

Factors associated with vision loss in idiopathic intracranial hypertension patients with severe papilledema.

Our aim was to compare factors associated with poor versus good visual outcomes in idiopathic intracranial hypertension (IIH) patients with severe papilledema at initial presentation. Retrospective review of consecutive IIH patients (1/1/2013-6/10/2023) with severe papilledema (Frisén grade 4-5 and/or atrophy in at least one eye); Patients were divided into "poor visual outcome" (poor visual acuity and constricted visual field in at least one eye) and "good visual outcome" (good visual acuity and only mild visual field changes in both eyes) at >6 months for medically-treated patients and >3 months follow-up for surgically-treated patients. We included 134 IIH patients with severe papilledema (70 had poor and 64 had good visual outcomes). No significant differences existed for age, gender, race, hypertension, haemoglobin, or cerebrospinal fluid opening pressure. The poor-outcome group had significantly greater BMI (mean 39.2 vs 35.1 kg/m2, p = 0.004), and worse initial HVF-MD (-20.04 vs -5.81 dB, p < 0.0001). Poor-outcome patients saw more prior health-care providers (4.7 vs 2.4, p < 0.0001), with delayed neuro-ophthalmology encounters (58.5 vs 15.2 weeks, p = 0.001). 41.4% of poor-outcome patients were initially seen in outside emergency departments (ED) (vs 14.1% of good-outcome patients, p = 0.0005), while only 27.1% were seen by eye-care providers (vs 53.1% of good-outcome patients, p = 0.0027). No poor-outcome patients initially consulted our institution's ED vs 7.8% of good-outcome patients. Although patients with poor visual outcome did not seek medical care later than good outcome patients, they had delayed diagnosis/treatment because of prior outside ED visits andlack of prior eye-care provider evaluations, suggesting that early diagnosis and specialized management of papilledema is essential for patients with symptoms of intracranial hypertension.

Lineshape of Amplitude-Modulated Stimulated Raman Spectra

The amplitude modulation of a pump field and the phase-sensitive detection of a pump-induced intensity change of a probe field encompass a common practice in nonlinear spectroscopies to enhance the detection sensitivity. A drawback of this approach arises when the modulation frequency is comparable to the width of the spectral feature of interest, since the presence of sidebands in the amplitude-modulated pump field provides distortion to the observed spectral lineshape. This represents a problem when accurate measurements of spectral lineshapes and line positions are pursued, as recently happened in our group with the metrology of the Q(1) line in the 1-0 band of molecular hydrogen. The measurement was performed with a Stimulated Raman Scattering spectrometer that was calibrated, for the first time, against an optical frequency comb. In this work, we develop an analytical tool for nonlinear Stimulated Raman spectroscopies that allows us to precisely quantify spectral distortions arising from high-frequency amplitude modulation in one of the interacting fields. Once they are known, spectral distortions can be deconvolved from the measured spectra to retrieve unbiased data. The application of this tool to the measured spectra is discussed.

Separating urban heat island circulation and convective cells through dynamic mode decomposition

AbstractThis study applies dynamic mode decomposition (DMD) to three‐dimensional simulation results of urban heat island circulation (UHIC, which is horizontal circulation) and thermals (vertical convections). The aim of this study is to revisit how these phenomena coexist based on the characteristics of temporal changes in the flow field. We used DMD to obtain the dominant spatial patterns and information on temporal changes. One of the modes of horizontal wind, which does not change temporally (no oscillation or amplification), exhibits a spatial UHIC pattern. The unique feature of this UHIC mode is that there are small‐scale striated structures (150–200 m) and large‐scale convergence. The other modes are time‐varying (oscillating and decaying) and represent smaller spatial‐scale phenomena (150–250 m), such as thermals. The frequency of each mode takes various values, some of which are lower than the lifetime of thermals in accordance with the Deardorff convective scale (~10 min). These low‐frequency modes showed striated structures similar to that observed in the UHIC modes. These results suggest that UHIC and thermals deform each other through components that vary in long temporal scales.

Electron Acceleration in Magnetic Islands in Quasi-parallel Shocks

We report new theories and simulations for electron acceleration in magnetic islands generated by magnetic reconnection in the shock turbulence in a quasi-parallel shock, using a 2 and 1/2 dimensional particle-in-cell simulation. When an island is moving, unmagnetized electrons are accelerated by the Hall electric field pointing toward the island center. In a stationary island, some electrons are energized by “island betatron acceleration” due to the induction electric field when the island core magnetic field changes with time. In the simulation, almost all of the high-energy electrons in the shock transition region that show a power-law distribution are accelerated in ion-skin-depth-scale magnetic flux ropes, and about half of them are accelerated by the Hall electric field and island betatron acceleration. These mechanisms can produce a power-law electron distribution, and also inject electrons into the diffusive shock acceleration. The mechanisms are applicable to quasi-parallel shocks with high Alfvén Mach numbers (M A > 10), including planetary bow shocks and shocks in astrophysical objects such as supernova remnants.

Innovations in staffing and service delivery structures and modalities in small institutions

AbstractSmall institutions are in a unique and perhaps necessary position to innovate as the field changes, resources falter, and the needs of the next generation of students and families become apparent and quite different from those supported by our historical structures and service modalities. This article examines the literature surrounding historical and innovative practices that higher education can explore to inform the future of student development practice. Additionally, the article explores new structural models and examines the efficacy of retaining the scaled down versions of the structures of large universities instead of creating new modalities that increase staff performance, provide better work/life harmony, create more efficient and effective services and functions, while increasing student engagement and connection.

Change in organizational fields: the role of peripheral actors within the Colombian coffee industry (1960–2020)

Change in organizational fields: the role of peripheral actors within the Colombian coffee industry (1960–2020)

Tunable magnonic crystal in a hybrid superconductor–ferrimagnet nanostructure

One of the most intriguing properties of magnonic systems is their reconfigurability, where an external magnetic field alters the static magnetic configuration to influence magnetization dynamics. In this paper, we present an alternative approach to tunable magnonic systems. We studied theoretically and numerically a magnonic crystal induced within a uniform magnetic layer by a periodic magnetic field pattern created by the sequence of superconducting strips. We showed that the spin-wave spectrum can be tuned by the inhomogeneous stray field of the superconductor in response to a small uniform external magnetic field. Additionally, we demonstrated that modifying the width of superconducting strips and separation between them leads to the changes in the internal field which are unprecedented in conventional magnonic structures. The paper presents the results of semi-analytical calculations for realistic structures, which are verified by finite-element method computations.

Competing effects of wind and buoyancy forcing on ocean oxygen trends in recent decades

Ocean deoxygenation is becoming a major stressor for marine ecosystems due to anthropogenic climate change. Two major pathways through which climate change affects ocean oxygen are changes in wind fields and changes in air-sea heat and freshwater fluxes. Here, we use a global ocean biogeochemistry model run under historical atmospheric forcing to show that wind stress is the dominant driver of year-to-year oxygen variability in most ocean regions. Only in areas of water mass formation do air-sea heat and freshwater fluxes dominate year-to-year oxygen dynamics. The deoxygenation since the late 1960s has been driven mainly by changes in air-sea heat and freshwater fluxes. Part of this deoxygenation has been mitigated by wind-driven increases in ventilation and interior oxygen supply, mainly in the Southern Ocean. The predicted slowdown in wind stress intensification, combined with continued ocean warming, may therefore greatly accelerate ocean deoxygenation in the coming decades. The fact that the model used here, along with many state-of-the-art forced ocean models, underestimates recent ocean deoxygenation indicates the need to use forcing fields that better represent pre-industrial conditions during their spin-up.

Visual field prediction based on temporal-spatial feature learning

Glaucoma stands as the leading irreversible cause of blindness worldwide. Regular visual field examinations play a crucial role in both diagnosing and treating glaucoma. Predicting future visual field changes can assist clinicians in making timely interventions to manage the progression of this disease. To integrate temporal and spatial features from past visual field examination results and enhance visual field prediction, a convolutional long short-term memory (ConvLSTM) network was employed to construct a predictive model. The predictive performance of the ConvLSTM model was validated and compared with other methods using a dataset of perimetry tests from the Humphrey field analyzer at the University of Washington (UWHVF). Compared to traditional methods, the ConvLSTM model demonstrated higher prediction accuracy. Additionally, the relationship between visual field series length and prediction performance was investigated. In predicting the visual field using the previous three visual field results of past 1.5~6.0 years, it was found that the ConvLSTM model performed better, achieving a mean absolute error of 2.255 dB, a root mean squared error of 3.457 dB, and a coefficient of determination of 0.960. The experimental results show that the proposed method effectively utilizes existing visual field examination results to achieve more accurate visual field prediction for the next 0.5~2.0 years. This approach holds promise in assisting clinicians in diagnosing and treating visual field progression in glaucoma patients.

A Review of Advanced Hydrogel Applications for Tissue Engineering and Drug Delivery Systems as Biomaterials

Hydrogels are known for their high water retention capacity and biocompatibility and have become essential materials in tissue engineering and drug delivery systems. This review explores recent advancements in hydrogel technology, focusing on innovative types such as self-healing, tough, smart, and hybrid hydrogels, each engineered to overcome the limitations of conventional hydrogels. Self-healing hydrogels can autonomously repair structural damage, making them well-suited for applications in dynamic biomedical environments. Tough hydrogels are designed with enhanced mechanical properties, enabling their use in load-bearing applications such as cartilage regeneration. Smart hydrogels respond to external stimuli, including changes in pH, temperature, and electromagnetic fields, making them ideal for controlled drug release tailored to specific medical needs. Hybrid hydrogels, made from both natural and synthetic polymers, combine bioactivity and mechanical resilience, which is particularly valuable in engineering complex tissues. Despite these innovations, challenges such as optimizing biocompatibility, adjusting degradation rates, and scaling up production remain. This review provides an in-depth analysis of these emerging hydrogel technologies, highlighting their transformative potential in both tissue engineering and drug delivery while outlining future directions for their development in biomedical applications.

Mild polarization electric field in ultra-thin BN-Fe-graphene sandwich structure for efficient nitrogen reduction

The electrocatalytic N2 reduction reaction (NRR) is expected to supersede the traditional Haber-Bosch technology for NH3 production under ambient conditions. The activity and selectivity of electrochemical NRR are restricted to a strong polarized electric field induced by the catalyst, correct electron transfer direction, and electron tunneling distance between bare electrode and active sites. By coupling the chemical vapor deposition method with the poly(methyl methacylate)-transfer method, an ultrathin sandwich catalyst, i.e., Fe atoms (polarized electric field layer) sandwiched between ultrathin (within electron tunneling distance) BN (catalyst layer) and graphene film (conducting layer), is fabricated for electrocatalytic NRR. The sandwich catalyst not only controls the transfer of electrons to the BN surface in the correct direction under applied voltage but also suppresses hydrogen evolution reaction by constructing a neutral polarization electric field without metal exposure. The sandwich electrocatalyst NRR system achieve NH3 yield of 8.9 μg h−1 cm−2 and Faradaic Efficiency of 21.7%. The N2 adsorption, activation, and polarization electric field changes of three sandwich catalysts (BN-Fe-G, BN-Fe-BN, and G-Fe-G) during the electrocatalytic NRR are investigated by experiments and density functional theory simulations. Driven by applied voltage, the neutral polarized electric field induced by BN-Fe-G leads to the high activity of electrocatalytic NRR.

Research on leakage characteristics of working clearances of hydrogen circulation pump

The volumetric efficiency of the hydrogen circulation pump (HCP) is mainly affected by the amount of leakage in working clearances. Studying the leakage characteristics of working clearances is of great significance for optimizing the performance of the HCP. Therefore, this paper developed a three-blade elliptical conjugate rotor HCP, and compared the results of experiments and simulations for different working conditions. On this basis, the flow rate, pressure, and internal flow field changes of radial clearance models and axial clearance models with four different scales of 0.1mm, 0.14mm, 0.18mm, and 0.22 mm were studied. The results indicate that: under four different pressure ratios and rotational speeds, the simulation results using the overlapping grid method showed a maximum difference of 4.17% compared to the experimental results, verifying the reliability of the simulation calculation method; the average flow rate of the HCP is linearly inversely proportional to both the radial clearance and the axial clearance, with a decrease rate of 11.6 Nm3/h and 5.8 Nm3/h as the clearance size increases by 0.04 mm; the radial clearance leakage of the same size is higher than the axial clearance, the leakage value in the radial clearance between the rotors is higher than that between the rotor and the pump casing, and the internal leakage of axial clearance is not evenly distributed, with higher leakage value in the middle area than that in the left and right areas.

Startup experiment with the newly installed lower tungsten divertor of KSTAR

Plasma startup experiments after the KSTAR upgrade of a lower divertor from carbon to tungsten have been studied during the KSTAR 2023 plasma campaign. In-vessel eddy currents, especially those induced on the divertor supporting structure in the toroidal direction, are significantly altered by the upgrade of the lower divertor configuration. These changes could affect the poloidal field configuration of the plasma startup phase, which is essential for the reliable breakdown and burn-through of deuterium neutral gas and the stable rise of the plasma current. Here, we present the development process of a new startup scenario that considers these upgrades. The vacuum magnetic field design code was utilized to estimate the changes in the poloidal field due to the new divertor configuration. Modifications to the startup scenario were prepared to compensate for the different effects of eddy currents, and experimental validation and optimization were performed during the initial phase of the KSTAR 2023 campaign. The final version of the startup scenario and plasma startup data are presented, and the reliability of the new startup scenario was also confirmed throughout the remainder of the KSTAR campaign.