Nonlinear dynamics of EEG responses to unmanned vehicle visual detection with different levels of task difficulty.

The main objective of this study was to examine the presence of chaos in the EEG recordings of brain activity under simulated unmanned ground vehicle visual detection scenarios with different levels of task difficulty. One hundred and fifty people participated in the experiment and completed four visual detection task scenarios: (1) change detection, (2) a threat detection task, (3) a dual-task with different change detection task rates, and (4) a dual-task with different threat detection task rates. We used the largest Lyapunov exponent and correlation dimension of the EEG data and performed 0-1 tests on the EEG data. The results revealed a change in the level of nonlinearity in the EEG data corresponding to different levels of cognitive task difficulty. The differences in EEG nonlinearity measures among the studied levels of task difficulty, as well as between a single task scenario and a dual-task scenario, have also been assessed. The results increase our understanding of the nature of unmanned systems' operational requirements.

The Chaotic Behavior of the Spread of Infection during the COVID-19 Pandemic in Japan.

In December 2019, China reported a new virus identified as SARS-CoV-2, causing COVID-19, which soon spread to other countries and led to a global pandemic. Although many countries imposed strict actions to control the spread of the virus, the COVID-19 pandemic resulted in unprecedented economic and social consequences in 2020 and early 2021. To understand the dynamics of the spread of the virus, we evaluated its chaotic behavior in Japan. A 0-1 test was applied to the time-series data of daily COVID-19 cases from January 26, 2020 to August 5, 2021 (3 days before the end of the Tokyo Olympic Games). Additionally, the influence of hosting the Olympic Games in Tokyo was assessed in data including the post-Olympic period until October 8, 2021. Even with these extended time period data, although the time-series data for the daily infections across Japan were not found to be chaotic, more than 76.6% and 55.3% of the prefectures in Japan showed chaotic behavior in the pre- and post-Olympic Games periods, respectively. Notably, Tokyo and Kanagawa, the two most populous cities in Japan, did not show chaotic behavior in their time-series data of daily COVID-19 confirmed cases. Overall, the prefectures with the largest population centers showed non-chaotic behavior, whereas the prefectures with smaller populations showed chaotic behavior. This phenomenon was observed in both of the analyzed time periods (pre- and post-Olympic Games); therefore, more attention should be paid to prefectures with smaller populations, in which controlling and preventing the current pandemic is more difficult.

The COVID-19 Infection Diffusion in the US and Japan: A Graph-Theoretical Approach.

Coronavirus disease 2019 (COVID-19) was first discovered in China; within several months, it spread worldwide and became a pandemic. Although the virus has spread throughout the globe, its effects have differed. The pandemic diffusion network dynamics (PDND) approach was proposed to better understand the spreading behavior of COVID-19 in the US and Japan. We used daily confirmed cases of COVID-19 from 5 January 2020 to 31 July 2021, for all states (prefectures) of the US and Japan. By applying the pandemic diffusion network dynamics (PDND) approach to COVID-19 time series data, we developed diffusion graphs for the US and Japan. In these graphs, nodes represent states and prefectures (regions), and edges represent connections between regions based on the synchrony of COVID-19 time series data. To compare the pandemic spreading dynamics in the US and Japan, we used graph theory metrics, which targeted the characterization of COVID-19 bedhavior that could not be explained through linear methods. These metrics included path length, global and local efficiency, clustering coefficient, assortativity, modularity, network density, and degree centrality. Application of the proposed approach resulted in the discovery of mostly minor differences between analyzed countries. In light of these findings, we focused on analyzing the reasons and defining research hypotheses that, upon addressing, could shed more light on the complex phenomena of COVID-19 virus spread and the proposed PDND methodology.

The Chaotic Behavior of the Spread of Infection During the COVID-19 Pandemic in the United States and Globally.

In December 2019, China announced the breakout of a new virus identified as coronavirus SARS-CoV-2 (COVID-19), which soon grew exponentially and resulted in a global pandemic. Despite strict actions to mitigate the spread of the virus in various countries, COVID-19 resulted in a significant loss of human life in 2020 and early 2021. To better understand the dynamics of the spread of COVID-19, evidence of its chaotic behavior in the US and globally was evaluated. A 0-1 test was used to analyze the time-series data of confirmed daily COVID-19 cases from 1/22/2020 to 12/13/2020. The results show that the behavior of the COVID-19 pandemic was chaotic in 55% of the investigated countries. Although the time-series data for the entire US was not chaotic, 39% of individual states displayed chaotic infection spread behavior based on the reported daily cases. Overall, there is evidence of chaotic behavior of the spread of COVID-19 infection worldwide, which adds to the difficulty in controlling and preventing the current pandemic.

Assessment of the perceived safety culture in the petrochemical industry in Japan: A cross-sectional study.

This study assessed the perceived safety culture among five petrochemical production companies in Japan. Current effects of the perceived safety culture on employee safety motivation and performance were also examined. A total of 883 workers from the five petrochemical companies, which were located in the Chugoku region of Japan, provided valid responses to the survey distributed by email. Structural equation modeling was used to evaluate the personnel safety culture in these industries. The endogenous variables considered in this study included petrochemical safety culture, personnel error behavior and personnel attitudes toward violation behaviors. Petrochemical personnel safety motivation was a mediating variable. This study's findings highlight the importance of the perceived safety culture as a significant component of the organizational culture that influences employee behaviors and safety attitudes. This study further verifies the significant impact of the perceived safety culture in this industry sector on improving petrochemical personnel safety motivation and performance. Future research should explore the differences between the subcultures that have formed under larger safety cultures within similar high-risk industries, such as construction, aviation, manufacturing and mining.

The complexity of human performance variability on watch standing task.

The primary objective of this study was to examine the complexity of human temporal variability of topside roving watch task in naval operations concerning the reported times of ship status and to explore the potential presence of chaotic behavior and fractal properties of the reported log times. Topside rover reporting time intervals recorded in the deck logs of the USS Jason Dunham over the 2013-2015 period were analyzed to understand the underlying complexity of the watch standing task that is critical to the success of naval operations. The results on the 0-1 test, analysis of the largest Lyapunov exponents, as well the exploration of the fractal dimension and 1/f spectral analyses, showed that the fluctuation of standing watch time reports data exhibits chaotic and fractal system properties. The critical implications of the study findings for the human-centered design of complex systems were also discussed.

Caffeine Intoxication in Pregnancy; a case Report.

Although fatalities due to caffeine intoxication are uncommon, a caffeine overdose may cause profound toxicity, resulting in tachycardia, arrhythmia, convulsions, vomiting, coma, and possibly death. In particular, high caffeine consumption while pregnant can cause increased fetal catecholamine levels, which could lead to increased fetal heart rate and placental vasoconstriction and impair fetal oxygenation. Therefore, caffeine intoxication in pregnant women should be treated immediately. Herein, we present a 33-year-old pregnant woman who was treated in our department after ingesting 4000mg of caffeine in an attempt to commit suicide. We successfully treated our patient, and she delivered a healthy baby at 38 weeks.

Assessment of Driver's Drowsiness Based on Fractal Dimensional Analysis of Sitting and Back Pressure Measurements.

The most effective way of preventing motor vehicle accidents caused by drowsy driving is through a better understanding of drowsiness itself. Prior research on the detection of symptoms of drowsy driving has offered insights on providing drivers with advance warning of an elevated risk of crash. The present study measured back and sitting pressures during a simulated driving task under both high and low arousal conditions. Fluctuation of time series of center of pressure (COP) movement of back and sitting pressure was observed to possess a fractal property. The fractal dimensions were calculated to compare the high and low arousal conditions. The results showed that under low arousal (the drowsiness state) the fractal dimension was significantly lower than what was calculated with high arousal. Accumulated drowsiness thus contributed to the loss of self-similarity and unpredictability of time series of back and sitting pressure measurement. Drowsiness further reduces the complexity of the posture control system as viewed from back and sitting pressure. Thus, fractal dimension is a necessary and sufficient condition of a decreased arousal level. It further is a necessary condition for detecting the interval or point in time with high risk of crash.

Extended Fitts' model of pointing time in eye-gaze input system - Incorporating effects of target shape and movement direction into modeling.

This study attempted to investigate the effects of the target shape and the movement direction on the pointing time using an eye-gaze input system and extend Fitts' model so that these factors are incorporated into the model and the predictive power of Fitts' model is enhanced. The target shape, the target size, the movement distance, and the direction of target presentation were set as within-subject experimental variables. The target shape included: a circle, and rectangles with an aspect ratio of 1:1, 1:2, 1:3, and 1:4. The movement direction included eight directions: upper, lower, left, right, upper left, upper right, lower left, and lower right. On the basis of the data for identifying the effects of the target shape and the movement direction on the pointing time, an attempt was made to develop a generalized and extended Fitts' model that took into account the movement direction and the target shape. As a result, the generalized and extended model was found to fit better to the experimental data, and be more effective for predicting the pointing time for a variety of human-computer interaction (HCI) task using an eye-gaze input system.

Evidence of Chaos in a Routine Watchstanding Task.

Research into human performance on naval ships often emphasizes the significance of shaping factors, such as vigilance, fatigue and circadian rhythm. However, few report on the presence of complex nonlinear dynamics and fractal dimensionality. This study examines over 7000 routine topside security checks on a U.S. Navy Destroyer performed over a twelve-month period. Time series analysis (0-1 test, analysis of Lyapunov exponent, state space plots, and graphical analysis) reveal the presence of chaotic behavior, harmonics attractors, and fractal structures. The presence of this level of complexity in a simple task demonstrates the need to integrate previous findings in human performance with new discoveries in complexity and fractional dynamics.

Effects of auditory and tactile warning on response to visual hazards under a noisy environment.

A warning signal presented via a visual or an auditory cue might interfere with auditory or visual information inside and outside a vehicle. On the other hand, such interference would be certainly reduced if a tactile cue is used. Therefore, it is expected that tactile cues would be promising as warning signals, especially in a noisy environment. In order to determine the most suitable modality of cue (warning) to a visual hazard in noisy environments, auditory and tactile cues were examined in this study. The condition of stimulus onset asynchrony (SOA) was set to 0ms, 500ms, and 1000ms. Two types of noises were used: white noise and noise outside a vehicle recorded in a real-world driving environment. The noise level LAeq (equivalent continuous A-weighted sound pressure level) inside the experimental chamber of each type of noise was adjusted to approximately 60 dB (A), 70 dB (A), and 80 dB (A). As a result, it was verified that tactile warning was more effective than auditory warning. When the noise outside a vehicle from a real-driving environment was used as the noise inside the experimental chamber, the reaction time to the auditory warning was not affected by the noise level.

A method for predicting the risk of virtual crashes in a simulated driving task using behavioural and subjective drowsiness measures.

This study proposed a procedure for predicting the point in time with high risk of virtual crash using a control chart methodology for behavioural measures during a simulated driving task. Tracking error, human back pressure, sitting pressure and horizontal and vertical neck bending angles were measured during the simulated driving task. The time with a high risk of a virtual crash occurred in 9 out of 10 participants. The time interval between the successfully detected point in time with high risk of virtual crash and the point in time of virtual crash ranged from 80 to 324 s. The proposed procedure for predicting the point in time with a high risk of a crash is promising for warning drivers of the state of high risk of crash. Practitioner Summary: Many fatal crashes occur due to drowsy driving. We proposed a method to predict the point in time with high risk of virtual crash before such a virtual crash occurs. This is done using behavioural measures during a simulated driving task. The effectiveness of the method is also demonstrated.

Development of a method to predict crash risk using trend analysis of driver behavior changes over time.

OBJECTIVE: This study aimed at identifying and predicting in advance the point in time with a high risk of a virtual accident before a virtual accident actually occurs using the change of behavioral measures and subjective rating on drowsiness over time and the trend analysis of each behavioral measure. METHODS: Behavioral measures such as neck bending angle and tracking error in steering maneuvering during the simulated driving task were recorded under the low arousal condition of all participants who stayed up all night without sleeping. The trend analysis of each evaluation measure was conducted using a single regression model where time and each measure of drowsiness corresponded to an independent variable and a dependent variable, respectively. Applying the trend analysis technique to the experimental data, we proposed a method to predict in advance the point in time with a high risk of a virtual accident (in a real-world driving environment, this corresponds to a crash) before the point in time when the participant would have encountered a crucial accident if he or she continued driving a vehicle (we call this the point in time of a virtual accident). RESULTS: On the basis of applying the proposed trend analysis method to behavioral measures, we found that the proposed approach could predict in advance the point in time with a high risk of a virtual accident before the point in time of a virtual accident. CONCLUSION: The proposed method is a promising technique for predicting in advance the time zone with potentially high risk (probability) of being involved in an accident due to drowsy driving and for warning drivers of such a drowsy and risky state.

[Influence of the diagnosis and treatment guidelines for mycosis profunda (deep mycosis) in the field of emergency and critical care medicine--with reference to patient background].

PURPOSE: This study was designed to elucidate the present situation of diagnosis and treatment for mycosis in the field of emergency and critical care medicine following presentation of the diagnosis and treatment guidelines for deep mycosis (in February, 2003). METHODS: In patients (administered antimycotics or who have pyrexia showing no response to any antimicrobial drug), medically examined and suspected of having had a fungal infection at 15 medical institutions throughout Japan, participating in the Japanese Society for the Study of Critical Care for Mycosis during the period from May 2003 through August 2004 and with facilities for emergency and critical care medicine, patient background, risk factors, contents of treatment, and patient outcomes were totaled and assessed. RESULTS: The subjects of this assessment were 125 patients consisting of 87 (69.6%) men and 38 (30.4%) women. Their mean age was 59.6 years, and 36.8% were 70 years of age or older. Intravascular catheterization was conducted in 78.4% of the 125 subjects. Antimycotics were administered to 89 patients, and the frequencies of fluconazole (FLCZ) for the initial administration and during the period of data registration were the highest (74.2% and 80.9%, respectively). The frequency with which a carbapenem antimicrobial drug was administered prior to antimycotics was the highest (41.6%). Blood culture was conducted in 85 patients (68.0%), monitoring culture in 108 (86.4%). Fungi were detected in 10 patients (11.8%) with blood culture and 72 (66.7%) with monitoring culture. The frequency of Candida albicans detection was the highest, 50.0% (5/10), with blood culture. With monitoring culture as well, the frequency of C. albicans detection was the highest, 55.6% (40/72). Alleviation of fever at the completion of registration was recognized in 65.6%. The survival rates at the completion of and at 28 days after the start of data registration of were 78.4% and 69.6%, respectively. CONCLUSION: Many patients in the field of emergency and critical care medicine had risk factors for deep mycosis; 11.8% and 66.7% of our 125 subjects were positive on blood and monitoring cultures, respectively. The majority of the fungi detected belonged to the Candida group, and FLCZ was the most frequently used antimycotic.

[Influence of the diagnosis and treatment guidelines for mycosis profunda (deep mycosis) in the field of emergency and critical care medicine--the influences of conformity and non-conformity to the guidelines on the outcomes of patients].

PURPOSE: This study was designed to investigate the influence of "The diagnosis and treatment guidelines for deep mycosis" (hereinafter referred to as "the Guidelines") in Japan on the diagnosis and treatment of deep mycosis in the field of emergency and critical care medicine and their influences on patient outcomes. METHODS: In patients (administered antimycotics or who had pyrexia showing no response to any antimicrobial drug) medically examined and suspected of having had a fungal infection at 15 medical institutions throughout Japan, participating in the Japanese Society for the Study of Critical Care for Mycosis during the period from May 2003 through August 2004 and with facilities for emergency and critical care medicine, patient background, risk factors, awareness of the Guidelines, diagnosis, contents of treatment, and outcomes were investigated. On the basis of the data pertaining to these items, whether or not the course of diagnosis and treatment for each patient conformed to the diagnosis and treatment recommended in the Guidelines was retrospectively evaluated. Whether or not the treatment had been conducted with antimycotics and the doses recommended in the Guidelines, was also investigated, and outcomes were assessed according to conformity and non-conformity to the Guidelines. RESULTS: Of the 125 subjects assessed, 55.2% responded that they were conscious of the Guidelines. The subjects who had indications for the Guidelines included 10 (8.0%), who were definitely diagnosed as having had mycosis, 3 (2.4%) who were diagnosed as having had clinical mycosis, and 35 (28.0%) who were suspected of having had mycosis. In the remaining 77 (61.6%), whether their conditions were non-mycosis or mycosis could not be determined. The treatment conformed to the Guidelines in 25 subjects (20.0%), but did not in 23 (18.4%). In 77 subjects (61.6%), whether or not the condition had been mycosis could not be determined. The number of the patients in whom whether or not the treatment had conformed to the Guidelines could be determined was decreased and there was a marked influence of administration of antimycotics, which was based on the assumption that "pyrexia with no response to broad-spectrum antimicrobial drugs persists for at least 3 days" in the Guidelines, was given as the reason. There was no significant difference in outcomes (survival or death) at the end of the study based on whether or not the subject had been conscious of the Guidelines or whether or not the contents of treatment conformed to the Guidelines. The number of days that treatment was administered in the ICU was greater in the treatment conforming to the Guidelines than in that not conforming to the Guidelines, but the difference did not reach statistical significance. CONCLUSION: The Guidelines were recognized at the time of treatment by more than half of the patients registered, but there were actually only a few patients in whom the diagnosis and treatment conformed to the Guidelines. One possible reason is considered to be that there was a marked influence of one item of the Guidelines, i.e. "pyrexia without response to broad-spectrum antimicrobial drugs persists for at least 3 days", in patients with suspected mycosis, who receive empirical treatment, in terms of the reason. Future examination is considered to be needed regarding the validity of this item.

Predicting the severity of systemic inflammatory response syndrome (SIRS)-associated coagulopathy with hemostatic molecular markers and vascular endothelial injury markers.

INTRODUCTION: The changes in biomarkers of coagulation or fibrinolysis, anticoagulation, inflammation, and endothelial damage occur in patients with systemic inflammatory response syndrome (SIRS). The purpose of this study is to assess the prognostic value of these markers in patients with SIRS-associated hypercoagulopathy. METHODS: Sixty-six SIRS patients with a platelet count less than 15.0 x 10(4)/mm3 in three university hospital intensive care units were enrolled in this prospective, comparative study. Blood samples were obtained on day 0 and day 2. Twelve hemostatic, inflammatory, and vascular endothelial indices were measured and the data were compared between the severe group (patients with a total maximum Sequential Organ Failure Assessment score of 10 or more and nonsurvivors; n = 25) and the less-severe group (Sequential Organ Failure Assessment score <10; n = 41). RESULTS: Significant changes between the groups were observed in platelet count, fibrin or fibrinogen degradation products, interleukin-6, soluble thrombomodulin, antithrombin (AT) activity, and protein C activity, both on day 0 and on day 2. In contrast, the d-dimer, soluble fibrin, plasmin-[alpha]2-antiplasmin complex, and E-selectin levels were higher in the severe group only on day 2. No significant difference was seen regarding the thrombin-AT complex and total plasminogen activator inhibitor on both days. A comparison of the areas under the receiver operating characteristic curve revealed the AT activity to be the best predictor of a progression of organ dysfunction. CONCLUSION: The changes in some hemostatic molecular markers and vascular endothelial markers were conspicuous in patients with organ dysfunction. The AT activity is considered to be the most useful predictor of organ dysfunction.

[An experimental study for syndromic surveillance using OTC sales].

OBJECTIVES: We analyzed the possibility of using sales data on over-the-counter (OTC) medicine in syndromic surveillance for early detection and/or prediction of influenza pandemics. METHODS: Data who collected on daily November 2003-April 2004 sales of common cold medication commercially obtained from 600 pharmacies in Japan enrolled in reporting throughout the 2003/04 influenza season. OTC sales data were compared to daily influenza incidence data to determine correlations and predictability. Data included Sentinel Surveillance of influenza, National Surveillance of Dally Influenza Outpatients (Daily Case Reporting: DCR), and Mailing-List-Based Influenza Epidemic Database (MLflu). RESULTS: The seasonal influenza epidemic peak for 2003-2004 was observed on January 30, February 1, and February 2 for sentinel surveillance, DCR, and MLflu. Sales peaks of OTC medicines occured twice in 2003-2004 season, once at the end of the year and once on January 27. Peak OTC sales for common cold medication per pharmacy were preceded by 18, 21, and 13 days for sentinel surveillance, DCR, and MLflu. OTC sales successfully explained 74-85% in the variation of influenza incidence which is interpretable as sufficient power of explanation. CONCLUSIONS: OTC sales proved to be a good indicator of real-time surveillance for influenza epidemics. Further analysis on multiyear data is needed to demonstrate the robustness of results. To confirm the advantage in the system of real-time syndromic surveillance, it is also necessary to check explanatory power of OTC sales on the variation of influenza incidence with prospective datasets.

SIRS-associated coagulopathy and organ dysfunction in critically ill patients with thrombocytopenia.

BACKGROUND: Coagulopathy and thrombocytopenia often occur in critically ill patients, and disseminated intravascular coagulation (DIC) can lead to multiple organ dysfunction and a poor outcome. However, the relation between coagulopathy and systemic inflammatory response has not been thoroughly clarified. Thus, we evaluated coagulative activity, organ dysfunction, and systemic inflammatory response syndrome (SIRS) in critically ill patients with thrombocytopenia and examined the balance between coagulopathy and systemic inflammation. PATIENTS AND METHODS: Two hundred seventy-three patients, who were admitted to 13 critical care centers in Japan and fulfilled the criteria of platelet count of less than 150*10(9)/L, were included. Coagulative variables (platelet count, fibrin/fibrinogen degradation products, and DIC scores), organ dysfunction index (Sequential Organ Failure Assessment [SOFA] score), and SIRS score in each patient were evaluated for 4 consecutive days after fulfilling the above entry criteria. The effect of SIRS on coagulopathy and organ dysfunction was evaluated in these patients. RESULTS: Both the maximum SIRS score and entry SIRS score had significant relation to the maximum SOFA score during the observation period. Coagulation disorders indicated by the minimum platelet count, maximum DIC scores, and positivity for DIC worsened gradually with increases in SIRS scores. Both the minimum platelet count and maximum DIC scores were significantly correlated with the maximum SOFA score, indicating that a relation exists between coagulopathy and organ dysfunction. CONCLUSIONS: In critically ill patients with thrombocytopenia, coagulopathy and organ dysfunction progress with significant mutual correlation, depending on the increase in SIRS scores. The SIRS-associated coagulopathy may play a critical role in inducing organ dysfunction after severe insult.