Controlling the Connected Vehicle with Bi-Directional Information: Improved Car-Following Models and Stability Analysis.

Connected vehicle (CV) technologies are changing the form of traditional traffic models. In the CV driving environment, abundant and accurate information is available to vehicles, promoting the development of control strategies and models. Under these circumstances, this paper proposes a bidirectional vehicles information structure (BDVIS) by making use of the acceleration information of one preceding vehicle and one following vehicle to improve the car-following models. Then, we deduced the derived multiple vehicles information structure (DMVIS), including historical movement information of multiple vehicles, without the acceleration information. Next, the paper embeds the four kinds of basic car-following models into the framework to investigate the stability condition of two structures under the small perturbation of traffic flow and explored traffic response properties with different proportions of forward-looking or backward-looking terms. Under the open boundary condition, simulations on a single lane are conducted to validate the theoretical analysis. The results indicated that BDVIS and the DMVIS perform better than the original car-following model in improving the traffic flow stability, but that they have their own advantages for differently positioned vehicles in the platoon. Moreover, increasing the proportions of the preceding and following vehicles presents a benefit to stability, but if traffic is stable, an increase in any of the parameters would extend the influence time, which reveals that neither ß1 or ß2 is the biggest the best for the traffic.

Simplification of Carbon Bond Mechanism IV (CBM-IV) under Different Initial Conditions by Using Concentration Sensitivity Analysis.

Carbon Bond Mechanism IV (CBM-IV) is a widely used reaction mechanism in which VOCs are grouped according to the molecular structure. In the present study, we applied a sensitivity analysis on the CBM-IV mechanism to clarify the importance of each reaction under two different initial conditions (urban and low-NO scenarios). The reactions that exert minor influence on the reaction system are then screened out from the mechanism, so that a reduced version of the CBM-IV mechanism under specific initial conditions can be obtained. We found that in a typical urban condition, 11 reactions can be removed from the original CBM-IV mechanism, and the deviation is less than 5% between the results using the original CBM-IV mechanism and the reduced mechanism. Moreover, in a low-NO initial condition, two more reactions, both of which are nitrogen-associated reactions, can be screened out from the reaction mechanism, while the accuracy of the simulation is still maintained. It is estimated that the reduction of the CBM-IV mechanism can save 11-14% of the computing time in the calculation of the chemistry in a box model simulation.

Evaluation of MERRA-2 and CAMS reanalysis for black carbon aerosol in China.

Black carbon (BC) constitutes a pivotal component of atmospheric aerosols, significantly impacting regional and global radiation balance, climate, and human health. In this study, we evaluated BC data in two prominent atmospheric composition reanalysis datasets: the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) and the Copernicus Atmosphere Monitoring Service (CAMS), and analyzed the causes of their deviations. This assessment is based on observational data collected from 34 monitoring stations across China from 2006 to 2022. Our research reveals a significant and consistent decline in BC concentrations within China, amounting to a reduction exceeding 67.33%. However, both MERRA-2 and CAMS reanalysis data fail to capture this declining trend. The average annual decrease of BC in MERRA-2 from 2006 to 2022 is only 0.06 µg/m3 per year, while the BC concentration in CAMS even increased with an average annual value of 0.014 µg/m3 per year. In 2022, MERRA-2 had overestimated BC concentration by 20% compared to observational data, while CAMS had overestimated it by approximately 66%. In the regional BC concentration analysis, the data quality of the reanalysis data is better in the South China (RM = 0.59, RC = 0.53), followed by the North China (RM = 0.50, RC = 0.42). Reanalysis BC data in Northwest China and the Tibetan Plateau are difficult to use for practical analysis due to their big difference with observation. In a comparison of the anthropogenic BC emissions inventory used in the two atmospheric composition reanalysis datasets with the Multi-resolution Emission Inventory model for Climate and air pollution research (MEIC) emissions inventory, we found that: Despite the significant decline in China's BC emissions, MERRA-2 still relies on the 2006 emissions inventory, while CAMS utilizes emission inventories that even show an increasing trend. These factors will undoubtedly lead to greater deviations between reanalysis and observational data.

Spatio-temporal evolution of coupling coordination between new infrastructure and regional sustainability in China.

To achieve high-quality development, it is crucial to encourage the coordinated development of new infrastructure (NI) and regional sustainability (RS). Based on the coupling mechanism of NI and RS, this study develops a comprehensive evaluation index system, coupling coordination degree model (CCDM), spatial autocorrelation model, and standard deviation ellipse model used to estimate the coupling coordination degree (CCD) of NI-RS in China mainland between 2013 and 2020 and analyze the temporal and spatial evolution characteristic. The results showed the following: (1) The NI index fluctuated and increased, while the RS index increased year by year, showing a gradient-decreasing distribution pattern from east to west; (2) CCD increases year by year, but the spatial distribution is unbalanced, and CCD in eastern coastal areas is significantly higher than that in western areas. (3) The CCD of NI and RS showed a significant spatial positive correlation, showing that the high-value cluster in the east and the low-value cluster in the west. (4) The standard deviation ellipse of the national CCD showed a northeast-southwest distribution, the center of gravity migrated to the southwest, and the spatial clustering characteristics were significant. (5) Finally, the GM (1,1) model indicates a steady increase in CCD from 2021 to 2025. Based on the location distribution and evolution of the CCD between NI and RS in China, corresponding policy suggestions are put forward.

Variability of blood pressure response to orthostatism and reproducibility of orthostatic hypotension in hospitalized patients with acute ischemic stroke.

OBJECTIVE: Orthostatic hypotension (OH) which diagnosis is based on the measurement of the blood pressure response to orthostatism (BPRO) is a common condition associated with adverse cerebrovascular and cognitive prognosis. It is likely that the single measurement might underestimate the true prevalence of OH. This study investigated the prevalence and reproducibility of the diagnosis of OH and related risk factors in hospitalized acute ischemic stroke (AIS) patients with multiple measurements. MATERIALS AND METHODS: This study was a prospective cohort analysis of consecutive AIS patients admitted to the hospital. A total of 211 patients were included. BPRO was assessed five times at the same time on different days. RESULTS: OH was found in 33 cases (15.6%) in the initial set of measurements of the first day. A cumulative diagnosis of OH after five BPRO tests was found in 75 cases (35.5%). The reproducibility of the diagnosis of OH was mild or poor. In patients with a cumulative diagnosis of OH, 29 (38.7%) patients had orthostatic hypertension (OHTN). In multivariate analysis, the Fazekas scale (odds radio = 1.28, 95% confidence interval (CI), 1.04-1.59, P = 0.023) and extracranial carotid stenosis (≥70%) (odds radio = 3.64, 95% CI, 1.19-11.13, P = 0.023) were independent risk factors for OH. CONCLUSION: The reproducibility of OH is poor and the concurrent appearance of OH and OHTN is common in hospitalized AIS patients. Multiple measurements should be taken in hospitalized AIS patients when screening for OH especially patients with higher Fazekas scale and extracranial carotid stenosis (≥70%).

Description and evaluation of a newly developed emission inventory processing system (EMIPS).

Commonly available emission inventories are often incompatible with the input requirements of atmospheric chemistry models due to temporal and spatial resolution, pollutant types, etc. We present the Emission Inventory Processing System (EMIPS) version 1, an open-source and multi-scale atmospheric emission modeling framework that prepares specific emissions inputs for atmospheric chemistry models. EMIPS is a multifunctional and user-friendly system, coded in Jython and developed on the MeteoInfo software platform. It allows users to freely combine and process emission inventories to generate model-ready emissions data. The core functions of EMIPS include preprocessing, temporal allocation, spatial allocation, chemical speciation, and vertical allocation. We detail the implementation of each function in the body of this paper, and several examples are provided for illustration. The emission outputs obtained with EMIPS have been evaluated by simulating four pollutants (PM2.5, PM10, NO2, and O3) concentrations in January 2017 using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), and comparison of model results with the observations indicates the model can reproduce the temporal and spatial patterns of pollutants, suggesting that EMIPS is capable of supporting atmospheric chemistry modeling. We expect this work could help to improve air quality research and forecast.

Correlation between body composition and white matter hyperintensity in patients with acute ischemic stroke.

White matter hyperintensity (WMH) burden is associated with a higher risk of ischemic stroke. The relationship between WMH and obesity is somewhat controversial which might be interfered by different body composition such as skeletal muscle, fat and bone density. However, few researchers have evaluated the relationship between WMH burden and disaggregated body constituents in acute ischemic stroke (AIS) patients systematically. A total of 352 AIS patients were enrolled in this study. The subcutaneous adipose tissue, erector spinae muscle area and bone density were evaluated on the computed tomography scanning. The burden of WMH was evaluated using the Fazekas scale based on the fluid-attenuated inversion recovery sequence. The severity of overall WMH was defined as none-mild WMH (total Fazekas score 0-2) or moderate-severe WMH (total Fazekas score 3-6). Based on the severity of periventricular WMH (P-WMH) and deep WMH, patients were categorized into either a none-mild (Fazekas score 0-1) group or a moderate-severe (Fazekas score 2-3) group. We found that patients with moderate-severe WMH showed lower bone density and smaller erector spinae muscle area and subcutaneous adipose tissue than none-mild. The logistic regression analysis showed that the bone density was independently associated with moderate-severe overall WMH (odds radio = 0.98, 95% confidence interval, 0.972-0.992, P < .001) and similar results were found in the analyses according to P-WMH (odds radio = 0.98, 95% confidence interval, 0.972-0.992, P < .001). These findings suggest that among the AIS body composition, the bone density is independently associated with the severity of overall WMH and P-WMH.

Risk Assessment of (Herbal) Teas Containing Pyrrolizidine Alkaloids (PAs) Based on Margin of Exposure Approach and Relative Potency (REP) Factors.

Pyrrolizidine alkaloids (PAs) present distinct toxicity potencies depending on their metabolites and in vivo toxicokinetics. To represent the potency differences of various PAs, the interim relative potency (REP) factors have been derived. However, little is known about the risk assessment for (herbal) teas when taking REP factors into account. In this study, a set of 68 individual 1,2-unsaturated PA in 21 types of (herbal) teas was analyzed using LC-MS/MS. The REP factors for these PAs were applied on the PA levels. The margin of exposure (MOE) approach was employed to assess the risks of the exposure to PAs due to consumption of (herbal) teas. The results show that the total PA levels ranged from 13.4 to 286,682.2 µg/kg d.m., which were decreased by REP correction in most of the teas. The MOE values for tephroseris, borage and lemon balm (melissa) tea based on REP-corrected PA levels were below 10,000, assuming daily consumption of one cup of tea during a lifetime, indicating that consuming these teas may raise a concern. Our study also indicates a priority for risk management for tephroseris tea, as having nephrosis tea for more than 11.2 weeks during a 75-year lifetime would result in an MOE of 10,000.

Hemicranial postural headache as a first symptom of a spontaneous carotid cavernous fistula: A case report.

RATIONALE: Spontaneous carotid cavernous fistula (CCF) is rare, and the expression of headache caused by it can be variable. PATIENT CONCERNS: A case of a man hospitalized for high-intensity hemicranial headache which was aggravated by lying down and relieved when standing or sitting. The pain was of a pulsating character, localized on the right, behind the eye, followed by nausea and vomiting. He gradually appeared with ophthalmoplegia, decreased visual acuity and epistaxis. DIAGNOSIS: Digital subtraction angiogram (DSA) showed a pseudoaneurysm arising from the internal carotid artery (ICA) that projected anteriorly and medially into the sphenoid sinus with occluded fistula. INTERVENTIONS: The pseudoaneurysm was successfully treated with covered stent. OUTCOMES: The patient was then followed up clinically at the outpatient and seen in the outpatient clinic with no further episodes of nasal bleeding or new neurologic deficit. The vision loss and ophthalmoparesis were unchanged. LESSONS: Hemicranial postural headache may be the first and characteristic sign of spontaneous CCF.

Correlation of orthostatic hypotension with extracranial carotid and intracranial cerebral arteries atherosclerosis in patients with acute ischemic stroke under cerebral angiography.

OBJECTIVE: The clinical management of patients with acute ischemic stroke (AIS) is complicated by orthostatic hypotension, which might have close relationship with the atherosclerosis of cerebral arteries. The primary objectives were to evaluate the relationship of orthostatic hypotension with extracranial carotid arteries atherosclerosis (ECAS) and intracranial atherosclerosis (ICAS) in AIS patients. METHODS: This study was a prospective cohort analysis of consecutive AIS patients under cerebrovascular angiography. A total of 289 patients were included. orthostatic hypotension was defined as a systolic BP decline ≥20 mmHg or a diastolic BP decline ≥10 mmHg within 3 min of standing. Univariate and multivariate analysis were performed to investigate the association of the clinical variables with orthostatic hypotension. RESULTS: Orthostatic hypotension was identified in 80 (27.7%) of all patients. ECAS (≥70%) and ICAS (≥50%) was found in 39 (13.5%) and 71 (24.6%) respectively. In multivariate analysis, only diabetes mellitus (odds ratio = 2.00, 95% confidence interval, 1.12-3.58, P = 0.019) and ECAS (odds ratio = 1.97, 95% confidence interval, 1.54-2.51, P < 0.001) were independent risk factors for orthostatic hypotension. CONCLUSIONS: Orthostatic hypotension is a relatively common finding among patients with AIS. AIS patients should be screened for orthostatic hypotension, especially combined with severe ECAS and diabetes mellitus.

Risk perception and the warning strategy based on safety potential field theory.

Benefiting from the rapid development of communication and intelligent vehicle technology in recent years, most traffic information is capable of being collected, processed, and transmitted to each vehicle through a connected and automated vehicles (CAVs) system. To meet the higher requirements of driving safety in CAVs environment, it is necessary to develop more effective safety evaluation indicators that combine all the traffic information received by the vehicle. To this end, this study proposes a novel methodology for risk perception and warning strategy based on safety potential field model to minimize driving risk in the CAVs environment. A dynamic safety potential field model was constructed to describe the spatial distribution of driving risk encountered by vehicles. This safety potential field model can comprehensively consider the impact of various types of traffic information on driving risk. And then, a novel driving risk indicator, named potential field indicator (PFI), was established to evaluate the level of driving risk. Finally, an early warning strategy was proposed to prevent accidents, whose performance was evaluated by several simulations carried out through SUMO simulator. The comparison with some classic risk indicators indicate that our proposed PFI can more accurately reflect the actual driving risk faced by vehicles under different vehicle motion states and thus is more suitable for driving risk assessment in the CAVs environment. It is expected that the findings in this study could be valuable in improving the performance of strategic decision-making in driver assistance systems in the CAVs environment.