Rate Of Change Research Articles

Can “climate upheaval” be a more informative term than “climate change”?

Terminology frames reality and affects how people perceive and respond to it. What makes the global climate situation concerning is not simply a change in climate, but the anthropogenic change, in addition to natural climate variations, occurring at a rapid rate relative to the pre-industrial era. However, in general language, “climate change” does not differentiate itself from natural climate variations nor reflect the rate of change. Based on theoretical reasoning, this paper argues that “climate upheaval” frames and communicates the global climate situation more informatively. This is because “climate upheaval” highlights the additional change at a rapid rate, which is crucial for (1) describing and informing the current climate status, (2) understanding the impacts of climate on natural, socioeconomic, and cultural aspects, and (3) taking climate actions. This argument can serve as a hypothesis for future exploration. Specific questions for empirical tests may include: How do people interpret “climate upheaval” and “climate change”? Do people prefer “climate upheaval”, and why? Is the intended message of “climate upheaval” different from people’s perceptions? As certain terms may offer more utility and information than others, it is important to weigh the advantages and drawbacks of different terms. Strategies aimed at reducing potential confusion and misunderstanding associated with "climate upheaval" may include providing scientific clarification, establishing communication channels, and conducting public education on this term. Terminology does not solely represent scientific labels but also carries significant social and cultural implications, encompassing public perceptions, social mobilization, policymaking, governance, negotiations, and international initiatives.

Smoking Susceptibility and Trends Among Nonsmoking Adolescents: An International Study.

Smoking susceptibility is defined as a lack of firm decision against smoking, usually starts in the preparation and/or initiation stages of smoking behavior, and is a strong predictor of smoking experimentation during adolescence. However, the recent global prevalence and trends in smoking susceptibility among adolescents are not well documented. This study assessed global smoking susceptibility and secular trends among nonsmoking adolescents. Smoking susceptibility was analyzed using the most recent data from the Global Youth Tobacco Survey from 129 countries, where the data from each country were drawn from at least 1 survey conducted at any time between 1999 and 2020. Moreover, data from 82 countries were used to assess the average annual rate of change (AARC) in smoking susceptibility over time. Smoking susceptibility among nonsmoking adolescents was 19.6%. A U-shaped relationship was observed between susceptibility and a country's economic level. Most countries showed no changes in susceptibility over time. Countries with a significant upward trend in susceptibility were primarily high-income and upper middle-income countries in the American region. At the World Health Organization regional level, susceptibility significantly decreased in the European region (AARC: -3.5%; 95% confidence interval, -5.8 to -0.8); however, it significantly increased in the American region (AARC: 2.2%; 95% confidence interval, 1.3-3.1). Smoking susceptibility remains a serious public health challenge among adolescents worldwide. More public health policies are needed to reduce susceptibility and to control its upward trend in the American region and high-income countries.

Making sense of the induced emf in a coil using sensors and visualisation of the voltage–force parametric plot

We investigated the emf (V) induced with time (t) in a search coil due to an oscillating bar magnet along the axis of the coil using the IOLab device. Experimental data was simultaneously collected with the force sensor which tracked the oscillation of the magnet and the voltage sensor which gave real-time readings of the induced emf in the coil. For small amplitudes of oscillation, where the predominant interaction involved the top end of the magnet cutting through the plane of the coil, the V–t graph appeared sinusoidal. With increasing amplitudes of oscillation, the V–t graph started to lose its symmetry with an initial kink appearing within one half cycle and which eventually became an increasing hump as the amplitude of oscillation increased further due to the influence from the bottom end of the bar magnet which affected the overall rate of change of magnetic flux linkage through the coil. The data collected from the experiment was visualised using a novel parametric series of plots of induced emf (V) with force (F). We discussed various cases of the V–F parametric plot. Using a suitable Φ–h function and taking into consideration the rate of change of magnetic flux linkage with respect to displacement along the coil, we discussed how the emf induced changes with time with increasing amplitudes of oscillation.

Cluster stability-driven optimization for enhanced routing in heterogeneous vehicular networks

The new era of the Internet of Things is promoting the evolution of self-driving vehicles into connected and autonomous vehicles (CAVs). The deployment of CAVs in smart cities is highly dependent on the performance of their underlying networks known as vehicular networks. Designing an effective clustering approach is of great importance in such dynamic networks as it can significantly improve the reliability and scalability of the routing protocols. In this paper, we consider a heterogeneous vehicular network architecture that supports vehicle-to-vehicle and vehicle-to-infrastructure communications based on IEEE 802.11p and cellular networks (LTE/5G) with direct communications, namely cellular vehicle-to-everything (C-V2X) technologies. We introduce a novel clustering scheme for real-time routing based on the proposed network architecture. We formulate the problem of optimal clustering for connected and autonomous vehicles (OCCAV) and show that the problem is NP-hard. We then develop a clusters' stability maximization algorithm (CSM), which utilizes the stability degree of vehicles over a prediction horizon to efficiently solve the optimization problem in real-time. The algorithm is used within a rolling horizon framework for continuously solving the problem, making the resulting clusters adaptive to future traffic dynamics. We propose a hybrid routing protocol based on our clustering scheme, aiming to improve the packet delivery ratio and reduce the average delivery delay. For evaluation purposes, we use extensive realistic simulations based on mobility scenarios validated using real vehicular trajectories. The results demonstrate that our clustering scheme improves the alternative algorithms in terms of the average cluster head duration, cluster head change rate, cluster member duration, and overall stability by 61%, 62%, 44%, and 52%, respectively. CSM also outperforms clustering overhead by 54%. Compared to the other cluster-based routing, our scheme also achieves a higher packet delivery ratio by up to 30%, and a lower average delay by up to 52%. To provide an in-depth analysis of the optimality of our scheme and its alternatives, we also use the Gurobi optimizer to find an optimal solution to the OCCAV problem. The results suggest that our scheme can achieve near-optimal cluster stability.

Effects of dapagliflozin on body weight in patients with type 2 diabetes mellitus: Evidence‑based practice.

The dose-dependent pharmacological response to dapagliflozin in patients with type 2 diabetes mellitus (T2DM) with regard to weight loss remain unknown. The aim of the present study was to investigate the effects of dapagliflozin on weight loss in patients with T2DM. A total of 8,545 patients with T2DM from 24 randomized controlled trials reported in the literature were selected for inclusion in the study. Data from these trials were analyzed using maximal effect (Emax) models with nonlinear mixed effects modeling; the evaluation index was the body weight change rate from baseline values. Patients treated with 2.5 mg/day dapagliflozin exhibited an Emax of -3.04%, and the time taken for therapy to reach half of the Emax (ET50) was estimated to be 30.8 weeks for patients treated with this dose. Patients treated with 5, 10 and 20 mg/day dapagliflozin exhibited Emax values of -6.57, -4.12 and -3.23%, respectively, and their ET50 values were estimated to be 27.3, 20.4 and 4.23 weeks, respectively. The data indicated ideal linear relationships between individual predictions and observations, suggesting the optimal fitting of the final models. The present study is the first systematic analysis of the effect of dapagliflozin on weight loss in patients with T2DM. The application of dapagliflozin at 5 mg/day exhibited a greater weight loss effect compared with the other doses used, and the weight loss onset time shortened as the dose of dapagliflozin increased.

Effects of heat treatment on the profile of volatile flavor components in bamboo shoots

The effects of different heat treatment conditions (105, 110, and 120 °C; 10, 20, 30, 40, and 50 min) on the flavor profiles of bamboo shoots were investigated using headspace/solid-phase microextraction-gas chromatography/mass spectrometry/olfactometry-odor activity value (HS/SPME-GC/MS/O-OAV) and sensory analysis. Results indicated noticeable differences in the amount and rate of changes in both original and newly produced flavor components in bamboo shoots at different temperatures. The retention rates of hexanal at 105 °C, 110 °C, and 120 °C were 8.55–34.41%, 7.28–34.32%, and 5.22–11.08%, respectively, whereas (E)-2-hexenal, (E, E)-2,4-heptadienal, (E, Z)-2,6-nonadienal, 1-hexanol, 1-octen-3-ol and 2-pentylfuran were mostly lost after heat treatment. The content of three lipid oxidation compounds (octanal, nonanal, and decanal) increased 75.59–500.67%, while the content of newly generated Maillard reaction compounds (e.g. methional, furfural) increased (0–12.58 μg/kg) with heating temperature and time. Sensory analysis indicated that the bamboo shoots heated at 110 °C for 30 min had the best overall flavor. These findings suggested that moderate heat treatment could eliminate some grassy and mushroom flavors from bamboo shoots, enhancing their sweet flavor. This improvement could be favorable for the consumer acceptance of heat-processed bamboo shoots.

Disparities in access but not outcomes: Medicaid versus non-Medicaid patients in multidisciplinary chronic pain rehabilitation

Purpose: There are known disparities in chronic pain severity, treatment, and opioid-related risks amongst individuals from lower socioeconomic status, including Medicaid beneficiaries, but little is known about whether Medicaid beneficiaries benefit in a similar way from multidisciplinary chronic pain rehabilitation. This study investigated differences in clinical outcomes between Medicaid and non-Medicaid beneficiaries who completed a 3-week multidisciplinary chronic pain rehabilitation program.Methods: Participants (N = 131) completed a broad range of clinical measures pre- and post-treatment including pain severity, pain interference, depression, anxiety, objective physical functioning, and opioid misuse risk. Patients with Medicaid were compared with non-Medicaid patients in terms of baseline characteristics and rate of change, utilizing two-factor repeated measures analyses of variance.Results: There were baseline characteristic differences, with Medicaid beneficiaries being more likely to be African American, have higher rates of pain, worse physical functioning, and lower rates of opioid use. Despite baseline differences, both groups demonstrated significantly improved outcomes across all measures (p<.001) and no significant difference in rate of improvement.Conclusions: Results suggest that pain rehabilitation is as effective for Medicaid recipients as non-Medicaid recipients. Patients with Medicaid are particularly vulnerable to disparities in treatment, so efforts to expand access to multidisciplinary pain treatments are warranted.

Future land use simulation model-based landscape ecological risk prediction under the localized shared socioeconomic pathways in the Xiangjiang River Basin, China.

Landscape ecological risk (LER) is an effective index to identify regional ecological risk and measure regional ecological security. The localized shared socioeconomic pathways (LSSPs) can provide multi-scenario parameters of social and economic development for LER research. The research of LER under LSSPs is of scientific significance and practical value in curbing the breeding and spread of LER risk areas. In this study, land-cover raster files from 2010 to 2020 were used as the foundational data. Future land use simulation (FLUS), regression, and Markov chain models were used to predict the land cover patterns under the five LSSP scenarios in the Xiangjiang River Basin (XJRB) in 2030. Thus, an evaluation model was established, and the LER of the watershed was evaluated. We found that the rate of land cover change (LCC) in the XJRB between 2010 and 2020 had a higher intensity (increasing at an average of 18.89% per decade) than that projected under the LSSPs for 2020-2030 (averaging an increase of 8.58% per decade). Among the growth rates of all land use types in the XJRB, that of urban land was the highest (33.3%). From 2010 to 2030, the LER in the XJRB was classified as lower risk (33.73%), lowest risk (33.11%), and moderate risk (24.13%) for each decade. Finally, the LER exhibited significant heterogeneity among different scenarios. Specifically, the percentages of regions characterized by the highest (9.77%) and higher LER (9.75%) were notably higher than those in the remaining scenarios. The higher-level risk area under the localized SSP1 demonstrated a clear spatial reduction compared to those of the other four scenarios. In addition, in order to facilitate the differential management and control of LER by relevant departments, risk zoning was carried out at the county level according to the prediction results of LER. And we got three types of risk management regions for the XJRB under the LSSPs.

Impact of early MRI in ischemic strokes beyond hyper-acute stage to improve patient outcomes, enable early discharge, and realize cost savings

BackgroundEarly in-patient MR Imaging may assist in identifying stroke etiology, facilitating prompt secondary prevention for ischemic strokes (IS), and potentially enhancing patient outcomes. This study explores the impact of early in patient MRI on IS patient outcomes and healthcare resource use beyond the hyper-acute stage. MethodsIn this retrospective registry-based study, 771 admitted transient ischemic attack (TIA) and IS patients at Halifax's QEII Health Centre from 2015 to 2019 underwent in-patient MRI. Cohort was categorized into two groups based on MRI timing: early (within 48 h) and late. Logistic regression and Poisson log-linear models, adjusted for age, sex, stroke severity, acute stroke protocol (ASP) activation, thrombolytic, and thrombectomy, were employed to examine in-hospital, discharge, post-discharge, and healthcare resource utilization outcomes. ResultsAmong the cohort, 39.6 % received early in-patient MRI. ASP activation and TIA were associated with a higher likelihood of receiving early MRI. Early MRI was independently associated with a lower rate of symptomatic changes in neurological status during hospitalization (adjusted odds ratio [OR], 0.42; 95 % confidence interval [CI], 0.20–0.88), higher odds of good functional outcomes at discharge (1.55; 1.11–2.16), lower rate of non-home discharge (0.65; 0.46–0.91), shorter length of stay (regression coefficient, 0.93; 95 % CI, 0.89–0.97), and reduced direct cost of hospitalization (0.77; 0.75–0.79). ConclusionEarly in-patient MRI utilization in IS patients post-hyper-acute stage was independently associated with improved patient outcomes and decreased healthcare resource utilization, underscoring the potential benefits of early MRI during in-patient management of IS. Further research, including randomized controlled trials, is warranted to validate these findings.

The Influence of Spinous Process Union on Clinical Outcomes After Spinous Process Osteotomy for Lumbar Spinal Stenosis After 2 Years: A Secondary Analysis From the NORDSTEN-Study.

Lumbar spinal stenosis is a prevalent and increasingly important cause of low back pain, leg pain, and walking impairment. Minimally invasive decompressive techniques such as spinous process (SP) osteotomy have become more common in recent years. The main aim of this study was to investigate the proportion of complete SP union and whether complete radiological healing after the osteotomy is associated with superior clinical outcome after 2 years. In this retrospective cohort study, 149 patients were included from the Spinal Stenosis Trial, a part of the NORwegian Degenerative spondylolisthesis and spinal STENosis study. Computed tomography imaging was performed 2 years postoperatively. The number of osteotomies and the number of SP unions were recorded. Patients were divided into groups based on the degree of union: nonunion, partial union, and complete union. Rate of success (>30% improvement in Oswestry Disability Index [ODI]) and mean change in ODI were the primary outcome measures. We compared the differences between baseline and follow-up between the Degree of Union groups. The study included 102 of 149 eligible patients. Ten patients (9.8%) were classified as having nonunion, 15 (14.7%) as having partial union, and 77 (75.5%) as having complete union. Of the 155 osteotomies, there were 122 classified as union (77%). The success rate was 74%, with no influence of SP union. The mean change in the ODI was -20.1 (95% CI -37.0, 14.2) with no influence of SP union. We found no influence of SP union, classified by computed tomography, on clinical outcome 2 years after SP osteotomy in patients with lumbar spinal stenosis. Supplying useful information about SPO to assist surgeons in the choice of decompressive technique.

Longitudinal Rates of Change in Structural Parameters of Optical Coherence Tomography in Primary Angle Closure Glaucoma following Laser Iridotomy along with Peripheral Iridoplasty.

This study aimed to investigate longitudinal rates of change (LRCs) of structural parameters from optical coherence tomography (OCT) in patients with primary angle closure glaucoma (PACG) after laser iridotomy (LI) along with laser peripheral iridoplasty (PI). Among 146 patients diagnosed with PACG, thirty-two subjects (32 eyes) who underwent LI plus PI and accomplished more than five times of reliable OCT tests were included in the current retrospective study. Retinal nerve fiber layer (RNFL) and Bruch's membrane opening-minimum rim width (BMO-MRW) were measured by spectral-domain OCT with three month interval. LRCs of global and six Garway-Heath sectors were investigated using the linear mixed-effects model which adjusted BMO area, sex, and age. Imaging of dual Scheimpflug analyzer was performed before and at 1 week after LI with PI and yearly thereafter. The mean follow-up period was 32.28 ± 13.34 months with a mean number of 10.18 ± 3.33 OCT images. Baseline characteristics are as follows: age, 63 ± 7.9 years; female, 62.5%; intraocular pressure(IOP), 15.48 ± 4.79 mmHg; anterior chamber depth, 2.09 ± 0.18 mm; and mean deviation, -7.97 ± 8.48 dB. Global LRC of BMO-MRW was 0.86 ± 1.34 μm/yr and RNFL was -0.64 ± 0.22 μm/yr. IOP decreased significantly to 13.06 ± 2.21 mmHg (p=0.001) while anterior chamber volume (p=0.011) and mean anterior chamber angle (p=0.022) increased significantly after LI along with PI compared to the baseline at the final visit. LRC of a new parameter, BMO-MRW, and LRC of RNFL were relatively low in patients with PACG, following LI along with PI. After widening of the anterior chamber angle and decrease of IOP due to LI plus PI, PACG might show stable structural prognosis assessed by OCT.

Analysis of the influence of ions on degradation of benzamide with hydrodynamic cavitation technology

In recent years, hydrodynamic cavitation technology has become a research hotspot in various fields. This study establishes a benzamide model with different ion types, ion concentrations, and bubble radii. The model is used to study the diffusivity of water molecules on the benzamide wall and structural changes in benzamide. The influence of ion type, ion concentration, and bubble radius on the degradation of pollutants is examined. The results are as follows: the larger the bubble radius and ion concentration, the larger the rate of change of maximum radial distribution function of carbon atoms (w). The effect of ion type on the diffusion coefficient of water molecules on the benzamide wall is as follows: H2O2 > HCO3−1 > NO3−1. In terms of structural changes in the benzamide, in the model containing H2O2, ion concentration has a greater effect than bubble radius. In the model containing HCO3−1, bubble radius has a greater effect than ion concentration. In the model containing NO3−1, bubble radius and ion concentration have an equal effect. w decreases most in the model containing H2O2 and least in the model containing NO3−1. The model containing H2O2 produces the most powerful effect in benzamide pollutant degradation. This study provides technical guidance and a theoretical basis for the green treatment of pollutants using cavitation theory.

What is the effect of reducing the air change rate on the ventilation effectiveness in ultra-clean operating rooms?

The operating room (OR) department is one of the most energy-intensive departments of a hospital. The majority of ORs in the Netherlands have an air-handling installation with an ultra-clean ventilation system. However, not all surgeries require an ultra-clean OR. To determine the effect of reducing the air change rate on the ventilation effectivenessin ultra-clean ORs. Lower air volume ventilation effectiveness (VELv) of conventional ventilation (CV), controlled dilution ventilation (cDV), temperature-controlled airflow (TcAF) and unidirectional airflow (UDAF) systems were evaluated within a 4× 4m measuring grid of 1× 1m. The VELv was defined as the recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE). The CV, cDVLv and TcAFLv ventilation systems showed a comparable mixing characterin all areas (A, B and AB) when reducing the air change rate to 20/h. Ventilation effectiveness decreased when the air change rate was reduced, with the exception of the ACE. At all points for the UDAF-2Lv and at the centre point (C3) of the TcAFLv, higher RD10Lv and CRRLv were measured when compared with the other examined ventilation systems. The ventilation effectiveness decreased when an ultra-clean OR with an ultra-clean ventilation air-supply system was switched to an air change rate of 20/h. Reducing the air change rate in the OR from an ultra-clean OR to a generic OR will reduce the recovery degree (RD10) by a factor of 10-100 and the local air change rate (CRR) by between 42% and 81%.

Assessing frailty amongst older people admitted to hospital in a low-income setting: a multicentre study in northern Tanzania

BackgroundPopulations are ageing globally and Low- and Middle-Income Countries (LMICs) are experiencing the fastest rates of demographic change. Few studies have explored the burden of frailty amongst older people in hospital in LMICs, where healthcare services are having to rapidly adapt to align with the needs of older people. This study aimed to measure the prevalence of frailty amongst older people admitted to hospital in Tanzania and to explore their demographic and clinical characteristics.MethodsThis study had a prospective observational design. Over a six-month period, all adults ≥ 60 years old admitted to medical wards in four hospitals in northern Tanzania were invited to participate. They were screened for frailty using the Clinical Frailty Scale (CFS) and the Frailty Phenotype (FP). Demographic and clinical characteristics of interest were recorded in a structured questionnaire. These included the Barthel Index, the Identification of Elderly Africans Instrumental Activities of Daily Living (IADEA-IADL) and Cognitive (IDEA-Cog) screens, the EURO-D depression scale and Confusion Assessment Method.Results540 adults aged ≥ 60 were admitted, and 308 completed assessment. Frailty was present in 66.6% using the CFS and participants with frailty were significantly older, with lower levels of education and literacy, greater disability, greater comorbidity, poorer cognition and higher levels of delirium. Using the FP, 57.0% of participants were classed as frail though a majority of participants (n = 159, 51.6%) could not be classified due to a high proportion of missing data.ConclusionsThis study indicates that the prevalence of frailty on medical wards in northern Tanzania is high according to the CFS. However, the challenges in operationalising the FP in this setting highlight the need for future work to adapt frailty screening tools for an African context. Future investigations should also seek to correlate frailty status with long-term clinical outcomes after admission in this setting.

Laser-assisted two-proton radioactivity

In this work, we systematically investigate the two-proton (2p) radioactivity assisted by an ultra-intense laser field within a deformed one-parameter model (OPM). The results show that the ultra-intense laser hardly affects the preformation probability of the emitted 2p-pair, but it can change the 2p radioactive half-lives to a finite extent by affecting the penetrability probability. Moreover, we compare the responses of different 2p radioactivity nuclei to the laser field, and it is found that the 2p radioactivity of nuclei with a low decay width are more easily influenced by the intense laser field. Furthermore, the effects of different physical parameters of a laser pulse on the 2p radioactivity were also discussed. The calculations indicate that the lasers characterized by shorter wavelengths and higher intensities exert a more significant influence on the rate of the average change in pulse duration. Finally, we extended the deformed OPM to predict the half-lives of 2p radioactivity candidates and identified the possible experimental objects of the laser-assisted 2p radioactivity. This study may promote the possibility of future experimental investigations on extensive facilities like GSI and ELI-NP, etc.

Modeling of Linearized Generator Inertia Constraints for Unit Commitment

This study presents a novel approach to modeling linearized inertia constraints of generators, considering frequency stability, and applies it to the unit commitment (UC). Specifically, we modeled the average rate of change of frequency (RoCoF) constraint and the minimum frequency constraint using the analytical expression derived from the reduced frequency response (RFR) model. We also considered the load-damping constant as a variable. As the power system has different nonlinear characteristics according to its operating status, the system can be expressed as several different systems. Each subsystem, with its own properties at a given operating point, is modeled as a single-machine system, categorized by pumped storage hydropower (PSH) status. The minimum frequency of each subsystem is determined by its individual machine time constant. We incorporated an additional constraint to ensure the quasi steady-state performance of frequency. This constraint can be omitted when it is not necessary. The proposed concepts have been validated on the Korean Power System. The UC, with the proposed inertia constraints, can secure system inertia and primary frequency response (PFR) that satisfies frequency stability. Our proposed method is more efficient in securing inertia and PFRs and more economical in terms of generation cost compared to existing methods.

Predicting functional decline in aging and Alzheimer's disease with PET-based Braak staging.

The progression of PET-based Braak stages correlates with cognitive deterioration in aging and Alzheimer's disease. Here, we investigate the association between PET-based Braak stages and functional impairment and assess whether PET-based Braak staging predicts a longitudinal decline in the performance of activities of daily living. In this cohort study, we evaluated cognitively unimpaired individuals and individuals with mild cognitive impairment or Alzheimer's disease dementia. Participants underwent [18F]MK6240 tau-PET, were assigned a PET-based Braak stage at baseline and were followed for a mean (SD) of 1.97 (0.66) years. Functional performance was evaluated with the Functional Activities Questionnaire, Everyday Cognition and functional Clinical Dementia Rating sum of boxes. Multiple linear regressions assessed the association of PET-based Braak stages with baseline functionality and with the longitudinal rate of change in functional scores, adjusting for age, sex and amyloid-β load. We employed voxel-based regression models to investigate the association between functionality and tau-PET signal and assessed the voxel overlap with Braak regions of interest. We included 291 individuals (181 cognitively unimpaired, 56 amyloid-β+ mild cognitive impairment and 54 amyloid-β+ Alzheimer's disease) aged 70.60 (7.48) years. At baseline, PET-based Braak stages III-IV (β = 0.43, P = 0.03) and V-VI (β = 1.20, P < 0.0001) showed associations with poorer Functional Activities Questionnaire scores. Similarly, stages III-IV (β = 0.43, P = 0.02) and V-VI (β = 1.15, P < 0.0001) were associated with worse Everyday Cognition scores. Only stages V-VI were associated with higher functional Clinical Dementia Rating sum of boxes (β = 1.17, P < 0.0001) scores. Increased tau-PET signals in all Braak regions of interest were linked to worse performance in all tools. The voxelwise analysis showed widespread cortical associations between functional impairment and tau-PET and high voxel overlap with Braak regions of interest. Baseline PET-based Braak stages V-VI predicted significant longitudinal functional decline as assessed by the Functional Activities Questionnaire (β = 1.69, P < 0.0001), the Everyday Cognition (β = 1.05, P = 0.001) and the functional Clinical Dementia Rating sum of boxes (β = 1.29, P < 0.0001). Our results suggest that functional impairment increases with the severity of tau accumulation. These findings also indicate that PET-based Braak staging is a good predictor of functional impairment in the Alzheimer's disease continuum. Finally, our study provides evidence for the clinical significance of the PET-based Braak staging framework.

A novel reinforcement learning policy optimization based adaptive VSG control technique for improved frequency stabilization in AC microgrids

In this paper, an improved Reinforcement Learning (RL) based approach for adaptive Virtual Synchronous Generator (VSG) control of grid-forming inverters is proposed. High penetration of inverter-based resources causes recurrent frequency stabilization issues. For this matter, a novel model-free Actor–Critic policy optimization technique is proposed to improve frequency transients metrics such as frequency nadir and Rate of Change of Frequency (RoCoF). Stability analysis of the VSG controlled system is conducted through small signal modeling to determine the stability margins of both the virtual inertia parameter J and damping coefficient Dp. The control problem is formulated in RL terms using a new technique for state, action and reward construction that improves the learning process of the agents. The proposed approach’s efficiency is tested for three RL algorithms, namely, Deep Deterministic Policy Gradient (DDPG), Soft Actor–Critic (SAC), and Twin-Delayed DDPG (TD3) with special attention given to the latter. Various performance metrics such as training time and maximum cumulative episodic reward are used to compare the three algorithms. The resulting agent based VSG adaptive controllers are simulated and then compared for power quality and frequency stabilization capabilities. Finally, a comparison between non-adaptive VSG and TD3 based VSG is presented to conclude on the efficiency improvements achieved by the proposed approach.

Impact of climate change on water quality evolution in cold regions using a water-heat-nitrogen processes coupled model.

Cold regions are particularly vulnerable to climate change. Thus, evaluating the response of water quality evolution to climate change in cold regions is vital for formulating adaptive countermeasures for pollution control under changing climatic conditions. Taking the Songhua River Basin (SRB) in Northeast China as the target area, we designed a water-heat-nitrogen coupled model based on the principle of water and energy transfer and nitrogen cycle processes model (WEP-N) in cold regions. The impact of climate change on pollution load and water quality was analyzed during the freezing, thawing, and non-freeze-thaw periods by taking the sudden change point (1998) of precipitation and runoff evolution in the SRB as the cut-off. The ammonia nitrogen load at Jiamusi station, the outlet control station in the SRB, was decreased by 1502.9 t in the change period (1999-2018) over the base period (1956-1998), with a - 9.2% decrease due to climate change. Compared to the ammonia nitrogen load during the base period, the ammonia nitrogen load decreased by - 171.3, - 506.9, and - 824.8 t during the freezing, thawing, and non-freeze-thaw periods, respectively, while the coefficient of variation showed an increasing trend during three periods, especially during the freezing and thawing periods. However, the water quality changes differed among periods owing to varying runoff during the year. Meanwhile, increasing runoff and decreasing ammonia nitrogen load improved water quality at Jiamusi station during the freezing period. During the thawing and non-freeze-thaw period, the water quality deteriorated due to the decrease in runoff more than the decrease in ammonia nitrogen load. Hence, the impact of climate change on water quality during thawing and non-freeze-thaw periods should be monitored to potentially offset the human influence on pollution control. The difference in the rate of change of the proportion of Class IV water between the two models with or without the soil freeze-thaw mechanism was 15.9%. The result shows that the application of a model that does not consider the freeze-thaw mechanism might slightly exaggerate the impact of climate change on water quality.

Long-Term Monitoring of Surface Water Dynamics and Analysis of Its Driving Mechanism: A Case Study of the Yangtze River Basin

In-depth insights into the profound impacts of climate change and human activities on water resources are garnered through the dynamic changes in surface water, a crucial aspect of effective water resource management and the preservation of aquatic ecosystems. This paper introduces an innovative approach employing the random forest algorithm for the systematic extraction and monitoring of surface water at large regional or national scales. This method integrates spectral bands, spectral indices, and digital elevation model data, offering a novel perspective on this critical task. A data-filling model is proposed to mitigate the impact of missing data due to cloud cover. Leveraging the capabilities of the Google Earth Engine (GEE), detailed information on surface water dynamics during the rainy and dry seasons in the Yangtze River Basin (YRB) from 1991 to 2021 is extracted using Landsat time series imagery. The analysis encompasses spatial-temporal variation characteristics and trends, with a specific focus on the intricate interplay between the areal extent of surface water and hydro-meteorological factors in each sub-basin of the YRB. Importantly, this includes considerations of potential groundwater contributions to surface water. Key findings from our research include: (1) Achieving a remarkable overall classification accuracy of 0.96 ± 0.03 in obtaining reliable surface water datasets with the support of GEE. (2) Identifying significant trends, such as a noteworthy increase in rainy season surface water bodies (+248.0 km2·yr−1) and a concerning decrease in surface ice/snow cover during both rainy and dry seasons, with change rates of −39.7 km2·yr−1 and −651.3 km2·yr−1, respectively. (3) Uncovering the driving mechanisms behind these changes, revealing positive correlations between the areal extent of rainy season surface water bodies and precipitation, as well as negative correlations between surface ice/snow cover area and average surface skin temperature. It is crucial to note that these driving factors exhibit variation among secondary river systems, underscoring the complexity of surface water dynamics. Furthermore, comparative analyses with existing surface water products are conducted, contributing to a deeper understanding of the advantages and uncertainties inherent in our proposed extraction method. The proposed method for large-scale surface water extraction not only enhances the monitoring of spatio-temporal surface water dynamics in the YRB but also provides valuable insights for the sustainable utilization and protection of water resources, considering the potential role of groundwater in supplementing surface water.