Pressure Research Articles

Acute Effects of Cadence-Controlled Walking on Cognition and Vascular Function in Physically Inactive Older Adults: A Randomized Crossover Study.

Cadence-controlled walking may be a desirable approach for older adults to self-monitor exercise intensity and achieve physical activity guidelines. We examined the acute effects of cadence-controlled walking on cognition and vascular function in physically inactive older adults. In a randomized crossover design, 26 participants (65% females, 67.8 ± 11.3years) underwent 30-min acute exercise (walking at 100steps/min) and control (sitting) conditions. We measured cognition, central blood pressure (BP), and arterial stiffness before, and immediately, after each condition. We observed significant Time × Condition interactions in the Flanker Inhibitory Control and Attention (Flanker) test and Dimensional Change Card Sort (DCCS) test scores, and in central systolic BP, central pulse pressure, and carotid to femoral pulse wave velocity (p < .05). The Flanker and DCCS scores significantly increased after walking (d = 0.4 and 0.5, respectively), but not after sitting. Central systolic BP, central pulse pressure, and carotid to femoral pulse wave velocity significantly increased after sitting but remained unchanged after acute walking (d = 0.4-0.2), with p-values < .05. After walking, significant correlations were observed between DCCS and diastolic BP and central pulse pressure change scores and change scores in central pulse wave velocity,Flanker, and DCCS (rs = -0.45 to -0.52). These findings suggest that a single bout of cadence-controlled walking elicited an immediate improvement in cognition and might have mitigated increases in arterial stiffness and central BP observed in the seated control condition. Further research is needed to examine the association between cognition and vascular function following acute exercise compared to control conditions. Our findings may have practical implications for developing daily physical activity recommendations for improving the cognitive health for successful aging.

Comparing the Atmospheric Responses to Reduced Arctic Sea Ice, a Warmer Ocean, and Increased CO2 and Their Contributions to Projected Change at 2°C Global Warming

Abstract We consider the combined and individual influences of Arctic sea ice loss, sea surface temperature (SST) warming, and the direct radiative effect of increased CO2 on the Northern Hemispheric climate. The surface climate (e.g., temperature and precipitation) and atmospheric circulation responses (e.g., sea level pressure and wind) to these drivers are quantified using simulations from the Polar Amplification Model Intercomparison Project (for sea ice loss and SST warming) and the Cloud Feedback Model Intercomparison Project (for increased CO2). We verify the linear additivity of the PAMIP-derived winter responses to sea ice loss and SST change. The responses to SST change are of greater magnitude than that due to sea ice loss or due to CO2 direct radiative forcing in most seasons and regions, excluding the Arctic. Notably, however, sea ice loss is at least as important as SST change for the winter atmospheric circulation response over the North Atlantic and Siberia. The dynamical responses to sea ice loss and SST change oppose each other in many regions in winter, while the responses to SST and CO2 direct radiative forcing are often opposing in summer. Such opposing responses are less evident for the thermodynamical response. The sum of all three responses reproduces well the spatial patterns of change at 2°C global warming in winter and autumn in phase 6 of the Coupled Model Intercomparison Project projections but overestimates their magnitude.

Subspace time series clustering of meteocean data to support ocean and coastal hydrodynamic modelling

High-quality ocean and coastal circulation predictions strongly rely on the availability of accurate time series of main meteocean forcing, e.g. wind velocity, atmospheric air pressure. In this study, we formulated and tested on a real case a new approach for generating medium term time series of meteocean data from available reanalysis database. We used the fifth generation reanalysis (ERA5) of global climate and weather data. The methodology is based on the K-means clustering technique, which groups unlabeled data into different clusters. In particular, we implemented a subspace clustering method that includes an automatic weighting of the meteocean variables of interest. To test the performance, we apply the algorithm to the Pearl River Estuary (China). By comparing the proposed methodology with standard clustering analysis, our results suggest that the obtained meteocean scenarios (clusters) better reproduce the time trends of the main variables, in terms of typical indexes used for evaluating the goodness of clustering. Moreover, we showed how using climatological averages, commonly adopted for circulation and wave models, could lead to loosing the important local variability of the meteocean signals. The present approach could represent an advancement in time series clustering to be coupled with ocean and regional circulation models in ocean engineering applications.

A comparison of the effect of oxygen partial pressure on microstructural evolution of PAN fibers during industrial carbon fiber production line at different altitudes

Understanding and regulating the oxidative stabilization behavior of polyacrylonitrile (PAN) precursor fibers are critical subjects of high-performance carbon fiber production technologies. Here, we performed continuous stabilization and carbonization of PAN fibers at industrial carbon fiber production lines in different locales (different oxygen partial pressure in atmosphere), and investigated the microstructural evolution of the fibers with a systematically analysis at different stages. Influence of oxygen partial pressure in oxidative stabilization atmosphere on tensile modulus of the obtained carbon fibers was obvious. Oxygen diffused into PAN fibers during oxidative stabilization, more homogeneous and crosslinked structures generated under higher oxygen partial pressure atmosphere, and gave the stabilized fibers lower skin-core ratio. The graphite layers gradually generated in the subsequent carbonization stages, and the gathered graphite layers transformed into graphite microcrystalline, the wide-angle x-ray diffraction (WAXD) demonstrated that higher oxygen partial pressure conditions contributed to the generation of higher crystallite preferred orientation and bigger crystallite size, Raman spectroscopy also confirmed the obtained carbon fibers with higher oxygen partial pressure conditions possessed more ordered graphite structures. Thus, relatively higher oxygen partial pressure in air gave the stabilized fibers more crosslinked structures, and contributed to the formation of high-performance carbon fibers.

A decoupling control of air supply for the PEM fuel cell with slide mode-active disturbance rejection controller

The air supply subsystem is crucial for optimizing proton exchange membrane fuel cells (PEMFCs). This study develops a transient model for the air subsystem and proposes a control strategy that decouples air pressure and flow using sliding mode-active disturbance rejection control (SM-ADRC). In this study, adjustments to the air compressor speed and the opening of the back-pressure valve are utilized to achieve this control strategy. The sliding mode-extended state observer (SM-ESO) is employed to estimate and compensate for uncertainties within the system, while the sliding mode-nonlinear state error feedback (SM-NLSEF) is used to simultaneously control air flow and pressure. The study evaluates the performance of the SM-ADRC controller across various scenarios and environmental pressures. Evaluations show that the SM-ADRC controller significantly outperforms traditional methods like Fuzzy-ADRC, ADRC, SMC, and PID, with overshoot reductions of 18.2%, 34.1%, 42.5%, and 63.7%, respectively, and adjustment time under 1 s. Additionally, SM-ADRC achieves a 4.1% and 1.8% improvement in efficiency compared to PID and ADRC.

A Theoretical Model-Based Methodology to the Design of Soft Structures: A Case Study of Pneumatic Mesh Actuators

Soft robots offer significant potential in various fields, including healthcare, education, and rescue operations, where actuators are critical components that influence power, precision, and environmental adaptability. However, the nonlinear properties of hyperelastic materials often necessitate reliance on empirical methods and extensive experimentation for actuator design. This study introduces a methodology for designing soft structures, exemplified by pneumatic mesh actuators. Utilizing numerical simulations to investigate deformation patterns and applying the principle of virtual work within a segmented constant curvature framework, a theoretical model was developed to describe the relationships between input air pressure, bending angle of a single airbag, and wall thickness. To validate the model's accuracy and applicability, bending tests were performed on actuators with varying wall thicknesses. A new pneumatic mesh actuator was designed and fabricated using the proposed method, with the experimental results showing a deviation of only 0.27° from the target bending angle under the specified air pressure. This confirms the effectiveness of the proposed design approach. This methodology has potential applications beyond pneumatic mesh actuators, extending to other areas of soft structure design.

Advanced Dual Mixed Refrigerant (DMR) Natural Gas Liquefaction Plant with Liquid Air: Focus on Configuration and Optimization

This study introduces a novel approach to integrating LNG cold energy into the dual mixed refrigerant (DMR) process, employing liquid air as a cold energy carrier. The DMR process is chosen for natural gas liquefaction due to its flexibility in adjusting mixed refrigerant compositions when external cold sources are utilized. Two configurations are investigated: the low-pressure liquid air (LPLA) process, which relies solely on heat exchange, and the high-pressure liquid air (HPLA) process, which involves the pressurization and expansion of liquid air. Additionally, two optimization strategies are explored: 'With Composition' (WC) optimization, which includes refrigerant composition as a variable, and 'Without Composition' (WOC) optimization, which does not. Utilizing liquid air reduces the load on the refrigeration cycle, leading to improved performance compared to the conventional DMR process. The air expansion generates additional power and cold energy, while WC optimization further reduces the flow rate of low-boiling-point components, significantly lowering compression energy consumption. As a result, the DMR-HPLA-WC process achieves a 44.17% reduction in energy consumption, an 8.7% improvement in exergy efficiency, and a 37.63% decrease in specific costs.

Effect of non-static pre-oxidation treatment on the cyclic ablation behavior of SiC-ZrC/SiC multilayer coated graphite

SiC-ZrC based ceramics have caught much attention as coatings for graphite materials. However, the coefficient of thermal expansion (CTE) mismatch between coatings and matrix severely limits their application in harsh environments. Herein, we proposed a non-static pre-oxidation treatment under an air pressure of 0.05 MPa to increase the surface roughness of graphite matrix to 18.054 μm and then prepared the SiC-ZrC/SiC multilayer coating on the pre-oxidized graphite. The results demonstrate that a firm interlocking structure was formed between SiC-ZrC/SiC multilayer coating and graphite matrix, which effectively improved the bonding strength and enhanced the cyclic ablation resistance of coatings. The bonding strength of SiC-ZrC/SiC multilayer coated on graphite pre-oxidized under negative pressure was 5.70±0.42 MPa, which was 54.89% higher than that on graphite pre-oxidized under atmospheric pressure (3.68±0.08 MPa). After the plasma ablation for 360 s (60 s × 6), the linear and mass ablation rates of SiC-ZrC/SiC multilayer coated graphite which was pre-oxidized under negative pressure were -0.083 μm/s and 0.101 mg/s, respectively.

A General Neurologist's Practical Diagnostic Algorithm for Atypical Parkinsonian Disorders: A Consensus Statement.

The most common four neurodegenerative atypical parkinsonian disorders (APDs) are progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal syndrome (CBS), and dementia with Lewy bodies (DLB). Their formal diagnostic criteria often require subspecialty experience to implement as designed and all require excluding competing diagnoses without clearly specifying how to do that. Validated diagnostic criteria are not available at all for many of the other common APDs, including normal pressure hydrocephalus (NPH), vascular parkinsonism (VP), or drug-induced parkinsonism (DIP). APDs also include conditions of structural, genetic, vascular, toxic/metabolic, infectious, and autoimmune origin. Their differential diagnosis can be challenging early in the course, if the presentation is atypical, or if a rare or non-neurodegenerative condition is present. This review equips community general neurologists to make an early provisional diagnosis before, or in place of, referral to a tertiary center. Early diagnosis would allay diagnostic uncertainty, allow prompt symptomatic management, provide disease-specific information and support resources, avoid further pointless testing and treatments, and create the possibility of trial referral. We address 64 APDs using one over-arching flow diagram and a series of detailed tables. Most instances of APDs can be diagnosed with a careful history and neurological exam, along with a non-contrast brain MRI. Additional diagnostic tests are rarely needed but are delineated where applicable. Our diagnostic algorithm encourages referral to a tertiary center whenever the general neurologist feels it would be in the patient's best interest. Our algorithm emphasizes that the diagnosis of APDs is an iterative process, refined with the appearance of new diagnostic features, availability of new technology, and advances in scientific understanding of the disorders. Clinicians' proposals for all diagnostic tests for the APDs, including repeat visits, should be discussed with patients and their families to ensure that the potential information to be gained aligns with their larger clinical goals. We designed this differential diagnostic algorithm for the APDs to enhance general neurologists' diagnostic skills and confidence and to help them address the less common or more ambiguous cases.

Mechanical Behavior of Origami-Based Inflatable Bistable Foldable Panels

Abstract Deployable structures are extensively used in engineering. A bistable panel structure, inspired by multistable origami, is proposed, capable of deployment and folding powered by air pressure. Prototypes were manufactured using planar laser etching technology based on geometric design. Mechanical behavior under out-of-plane compression, in-plane compression, and out-of-plane bending loads was analyzed through experiments. The foldable panel showed superior mechanical performance under out-of-plane compression, highlighting its potential as an ideal energy-absorbing material. In-plane compression and out-of-plane bending along the folding direction exhibited lower strength due to foldability, with failure modes involving rigidity loss from folding. The structure demonstrated good energy absorption characteristics during in-plane compression. As the angle of the unit increased during out-of-plane bending, mechanical performance improved, but the failure mode shifted to fracture. In in-plane compression and out-of-plane bending perpendicular to the folding direction, mechanical performance was enhanced, but the structure failed due to strength loss from fracture.

Osteoporosis in older patients with idiopathic normal pressure hydrocephalus

Osteoporosis in older patients with idiopathic normal pressure hydrocephalus

Experimental Analysis of Long-Term Fuel Trim Performance in a Gasoline Engine Under Various Operating Conditions

This paper analyzes the effect of operating conditions on the enrichment of the fuel-air mixture in a car engine due to a decrease in air mass with increasing altitude above sea level. This study focuses on fuel trim, particularly long-term fuel trim, in optimizing the composition of the fuel-air mixture before it enters the engine's combustion chamber. Experimental studies were conducted on the Bishkek–Osh highway in the Kyrgyz Republic, a road characterized by flat, mountainous, and high-altitude sections with complex terrain. Based on the research objectives, experimental results were obtained, and graphs of long-term fuel trim as a percentage of terrain altitude were constructed and analyzed for flat, mountainous, and high-altitude sections of the Bishkek–Osh highway. The study established that fuel trim indicators can be used to analyze changes in the air-fuel mixture's air excess coefficient (λ = 1, stoichiometric ratio). The reduction in long-term fuel trim was observed in flat, mountainous, and high-altitude sections as air density and pressure decreased with increasing altitude above sea level. The results show that with a reduction in long-term fuel trim to -6.25% to -7.81% at altitudes between 1500 and 3000 meters above sea level, the air excess coefficient (λ) drops to 0.92–0.94. At an altitude of 770 meters (flat terrain), λ was measured at 0.97. The difference in λ (0.03–0.05) indicates that an increase in altitude significantly affects the air-fuel ratio (AFR), impacting mixture formation during vehicle operation in mountainous and high-altitude conditions.

Multiple Treatment Strategies of Accessory Renal Artery Related Hypertension: Report of Two Cases and Literature Review.

Renovascular hypertension (RVH) is a primary cause of secondary hypertension, primarily driven by the activation of the renin-angiotensin-aldosterone system activation. Recently, growing studies suggested accessory renal artery (ARA) might also contribute to RVH. However, the treatment of ARA-related hypertension and whether to take interventional treatment lack consensus. Herein, we report two cases of ARA-related hypertension in our hospital. Imaging studies of both patients showed ARA stenosis. One patient had ARA occlusion well-compensated through tortuous collateral branches, achieving normal blood pressure by medical treatment alone. The other patient had ARA stenosis coexisted with main renal artery stenosis, and revascularization of both arteries led to a significant postoperative reduction in blood pressure. A literature review was conducted to summarize overall treatment strategies for ARA-related hypertension and clarify the relationship between ARA and hypertension. Recent research supported an association between ARA and hypertension. While medical therapy remains the first-line treatment for ARA-related hypertension, interventional procedures should be considered for patients whose blood pressure remains uncontrolled despite conservative management.

Normal pressure hydrocephalus in adult mice causes gait impairment, cognitive deficits, and urinary frequency with incontinence.

Normal pressure hydrocephalus (NPH) is marked by enlarged cerebral ventricles with normal intracranial pressure, plus three stereotypical symptoms: gait impairment, cognitive dysfunction, and urinary frequency with urge-incontinence. The neural circuit dysfunction responsible for each of these symptoms remains unknown, and an adult mouse model would expand opportunities to explore these mechanisms in preclinical experiments. Here, we describe the first mouse model of chronic, communicating hydrocephalus with normal intracranial pressure. Hydrocephalic male and female mice had unsteady gait and reduced maximum velocity. Despite performing well on a variety of behavioral tests, they exhibited subtle learning impairments. Hydrocephalic mice also developed urinary frequency, and many became incontinent. This mouse model, with symptoms resembling human NPH, can be combined with molecular-genetic tools in any mouse strain to explore the neural circuit mechanisms of these symptoms. Preclinical work using this hydrocephalus model will lead to the development of new treatments for NPH symptoms.Significance Statement Like human patients with normal pressure hydrocephalus (NPH), mice with communicating hydrocephalus develop enlarged cerebral ventricles with normal intracranial pressure plus three stereotypical symptoms: gait impairment, cognitive dysfunction, and urinary frequency with incontinence. This mouse model, with symptoms resembling human NPH, can be combined with molecular-genetic tools in any mouse strain to explore neural circuit mechanisms of NPH symptoms.

Why do patients with pheochromocytomas/paragangliomas exhibit significantly inconsistent elevation of catecholamines and their metabolites? a large Chinese cohort study.

Inconsistent elevation of catecholamines (CAs) and metanephrines (MNs) was observed in pheochromocytomas/paragangliomas (PPGLs). This study aimed to explore its potential causes and report the diagnostic efficacy of MNs and CAs in a large Chinese PPGL cohort. Clinical data and results of hormone tests were retrospectively collected. The sensitivity of plasma MNs and 24h-urinary CAs was analyzed. Clinical characteristics were compared between patients with positive and negative biochemical results, and among those with inconsistent elevation of MNs and CAs. Seven hundred and three patients were included, with a median onset age of 41.0 years. Plasma MNs (93% ~ 99%) showed prior diagnostic sensitivity to 24h-urinary CAs (74% ~ 89%). Patients with negative biochemical results presented as a smaller tumor (1.7 cm vs. 4.3 cm, P = 0.001), a higher proportion of normal blood pressure (60.0% vs. 20.5%, P = 0.002) and negative 131I-meta-iodobenzylguanidine (131I-MIBG) imaging (55.6% vs. 17.3%, P = 0.012). An earlier age of onset (40.0 vs. 41.0 vs. 44.5 years, P = 0.025), a higher proportion of paroxysmal hypertension (36.5% vs. 29.2% vs. 32.2%, P = 0.005) and the Epinephrine secretion type (79.3% vs. 37.7% vs. 48.0%, P < 0.001) were found in patients with the ratio of MNs/CAs elevation multiples <0.5 than those with the ratio between 0.5 and 2 or >2. Plasma MNs exhibited a superior sensitivity than 24-h-urinary CAs in the Chinese PPGL diagnosis. Patients with a small tumor, normal blood pressure and negative 131I-MIBG imaging were prone to express negative biochemical levels. Additionally, an obvious elevation of 24-h-urinary CAs than plasma MNs was correlated to paroxysmal hypertension and the Epinephrine type.

Karl Ziegler - Early Career of a Scientist.

Karl Ziegler is considered one of the most outstanding chemists of the 20th century. In particular, his work on organometallic mixed catalysts, which allows the polymerization of ethylene at normal pressure, led to a revolution in plastics production and changed the everyday life of all mankind. In 1963, he was awarded the Nobel Prize in Chemistry for this work, together with Giulio Natta. This article focuses on Ziegler's early career, which has received little attention to date. It describes his youth and study years in Marburg, which partly coincide with the First World War. Subsequently, his postdoctoral period is examined, which led him via Marburg and Frankfurt to his first associate professorship in Heidelberg. Special attention is paid to his relationship to National Socialism, which he opposed. As a result, Ziegler experienced professional difficulties in the 1930s, such as repeated rejection when filling various professorships. His appointment as a full professor in Halle and his subsequent directorship at the Max-Planck-Institut für Kohlenforschung (Coal Research), where he finally achieved his greatest research achievement, are described in the following.

High-intensity interval training is an effective exercise mode to maintain normal blood pressure during pregnancy: a randomized control trial.

Pregnant women are more susceptible to high blood pressure (BP) than the general adult population; therefore, all means of preventing this condition should be considered. High-intensity interval training (HIIT) is effective in this regard in the general population, but there is a lack of evidence of its effectiveness during pregnancy. This study aimed to compare an 8-week HIIT program to self-performed moderate-to-vigorous physical activity among pregnant women by evaluating changes in BP after a maximal progressive cardiorespiratory exercise test (CPET) performed at pre-intervention and post-intervention time points. A total of 54 Caucasian women in uncomplicated, singleton pregnancies (age 32 ± 4 years, 22 ± 4 weeks of gestation; M ± SD) with normal BP values completed the interventions. The experimental (HIIT) group (n = 34) completed an online supervised HIIT program consisting of three sessions per week and supplemented by an educational class once per week. Participants in the education (EDU) group (n = 20) attended an educational class once per week and were encouraged to perform moderate-to-vigorous physical activity (PA) on their own. Pre- and post-intervention, all women underwent a CPET on a cycle ergometer with a respiratory gas analyzer. On the day of the CPET, maternal systolic and diastolic BP (mmHg) was measured at rest (before the CPET) and approximately 60min after the CPET using an electronic BP monitor. Identical CPET and BP measurement protocols were employed for both the HIIT and EDU groups at the pre- and post-intervention time points. Pre-intervention, the HIIT and EDU groups both showed a decrease in systolic and diastolic BP after the CPET, though only the change in systolic BP was statistically significant (HIIT group: p = 0.01; EDU group: p = 0.001). Post-intervention, there were no significant differences in either group between resting and post-CPET BP. There were significant post-intervention differences in VO2peak (p < 0.001) and HRmax (p = 0.002) between the HIIT and EDU groups. From pre- to post-intervention, the EDU and HIIT groups both showed decreases in resting systolic or diastolic BP; there was a significant difference in systolic BP in the EDU group (p = 0.005) and a significant difference in diastolic BP in the HIIT group (p = 0.03). Both groups maintained normal BP values throughout the experiment. However, HIIT, in addition to maintaining normotension, improved cardiorespiratory fitness in pregnant women. It seems that both supervised HIIT and self-performed moderate-to-vigorous PA can be recommended as strategies to prevent BP disorders during pregnancy. More studies are needed to confirm our findings.Trial registration The full study protocol was registered in ClinicalTrials.gov (NCT05009433).

The association between hypertension and different types of dietary carbohydrates

Background Hypertension is the most prominent and well acknowledged chronic disease in developed countries and is a significant contributor to global mortality. The present study aimed to investigate the association between hypertension and different types of dietary carbohydrates. Method This cross-sectional study was conducted on 4184 people aged 35–70, including 1239 patients with hypertension and 2945 subjects with normal blood pressure (BP) in Sabzevar, Iran. The dietary intake data were collected through the administration of a semiquantitative Food Frequency Questionnaire. Utilizing Nutritionist IV software, dietary glucose, fructose, simple sugar, carbohydrate, and galactose consumption were evaluated. Results A direct association was found between dietary glucose and BP (odds ratio: 1.02; 95% CI: 1.01–1.05; P = 0.04). This association remained significant after adjusting for age. Further adjustments for education, marital status, job, physical activity, and BMI, and additional adjustments for energy intake did not change the results. Conclusion In summary, the present study identified a significant association between hypertension and dietary intake of glucose. Considering that carbohydrates are an essential part of the diet worldwide, these findings can be valuable in formulating dietary interventions for hypertensive patients.

Modelling of Carbon Monoxide and Suspended Particulate Matter Concentrations in a Rural Area Using Artificial Neural Networks

Air pollution is a growing concern in rural areas where agricultural production can be reduced by it. This article analyses data obtained as part of a research project. The aim of this study is to understand the influence of atmospheric pressure, air temperature, air relative humidity, longitude and latitude of the location, and indoor and outdoor environment on local rural workplace diversity of air pollutants such as carbon monoxide (CO) and suspended particulate matter (SPM), as well as the contribution of these variables to changes in such air pollutants. The focus is on four topics: motivation, innovation and creativity, leadership, and social responsibility. Furthermore, this study developed an artificial neural network (ANN) model to predict CO and SPM concentrations in the air based on data collected from the mentioned inputs. The related sensors were assembled on an Arduino Mega 2560 board to form a field-portable device to detect air pollutants and meteorological parameters. The sensors included an MQ7 sensor for CO concentration measurement, a Sharp GP2Y1010AU0F dust sensor for SPM concentration measurement, a DHT11 sensor for air temperature and air relative humidity measurement, and a BMP180 sensor for air pressure measurements. The longitude and latitude of the location were measured using a smartphone. Measurements were conducted from 20 December 2021 to 16 July 2022. Results showed that the overall average outdoor CO and SPM concentrations were 10.97 ppm and 231.14 μg/m3 air, respectively. The overall average indoor concentrations were 12.21 ppm and 233.91 μg/m3 air for CO and SPM, respectively. Results showed that the ANN model demonstrated acceptable performance in predicting CO and SPM in both the training and testing phases, exhibiting a coefficient of determination (R2) of 0.575, a root mean square error (RMSE) of 1.490 ppm, and a mean absolute error (MAE) of 0.994 ppm for CO concentrations when applying the testing dataset. For SPM concentrations, the R2, RMSE, and MAE using the test dataset were 0.497, 30.301 μg/m3 air, and 23.889 μg/m3 air, respectively. The most influential input variable was air pressure, with contribution rates of 22.88% and 22.82% in predicting CO and SPM concentrations, respectively. The acceptable performance of the developed ANN model provides potential advances in air quality management and agricultural planning, enabling a more accurate and informed decision-making process regarding air pollution. The results of short-term estimation of CO and SPM concentrations suggest that the accuracy of the ANN model needs to be improved through more comprehensive data collection or advanced machine learning algorithms to improve the prediction results of these two air pollutants. Moreover, as even lower cost devices can predict CO and SPM concentrations, this study could lead to the development some kind of virtual sensor, as other air pollutants can be estimated from measurements of particulate matters.

A high‐resolution climatological study of explosive cyclones in the Mediterranean region: Frequency, intensity and synoptic drivers

AbstractIn the complex context of climate change and in a heavily populated area like the Mediterranean region, understanding and studying explosive cyclones (ECs) is crucial because of their potential to cause extreme weather events, including strong winds, heavy rainfall, and significant disruptions to human activities and infrastructure, as happened in 2018 with the Vaia storm. The genesis and persistence of ECs, characterized by a rapid drop in central mean sea level pressure exceeding 12 hPa in 12 hours, are influenced by various physical processes and while water vapour convergence in the mid‐low troposphere is crucial, mid‐upper tropospheric cyclonic vorticity advection and upper tropospheric divergence also play significant roles. In this study, we used ERA5 hourly data of mean sea level pressure from 1979 to 2020 to analyse EC occurrences in the Mediterranean. The identification of EC events followed the 12‐hr deepening‐rate criterion introduced by Zhang et al. (2017), as shorter deepening rates definitions proved unreliable. A total of 80 ECs were identified and classified based on their spatial occurrence and magnitude, 34 of which were concentrated in the northwest of the basin, likely due to orographic deformation caused by the Alps on baroclinic waves originating from the Atlantic. The study also identified recurring synoptic patterns associated with the persistence of ECs over the sea, including the presence of potential vorticity (PV) streamers and mid‐tropospheric dry‐air intrusions. Empirical Orthogonal Function (EOF) analysis highlighted the Scandinavian pattern as the primary driver, with blocking conditions over western Russia and Scandinavia, and composite analyses revealed the intrusion of PV to various atmospheric levels, extending up to 500 hPa. In summary, this study offers valuable insights into the complex mechanisms governing EC formation in the Mediterranean Basin, shedding light on the synoptic patterns, atmospheric dynamics, and potential impacts on regional weather systems.