Level Of Alertness Research Articles

Improved sub-seasonal forecasts to support preparedness action for meningitis outbreak in Africa

West African countries are hit annually by meningitis outbreaks which occur during the dry season and are linked to atmospheric variability. This paper describes an innovative co-production process between the African Centre of Meteorological Applications for Development (ACMAD; forecast producer) and the World Health Organisation Regional Office for Africa (WHO AFRO; forecast user) to support awareness, preparedness and response actions for meningitis outbreaks. Using sub-seasonal to seasonal (S2S) forecasts, this co-production enables ACMAD and WHO AFRO to build initiative that increases the production of useful climate services in the health sector. Temperature and relative humidity forecasts are combined with dust forecasts to operationalize a meningitis early warning system (MEWS) across the African meningitis belt with a two-week lead time. To prevent and control meningitis, the MEWS is produced from week 1 to 26 of the year. This study demonstrates that S2S forecasts have good skill at predicting dry and warm atmospheric conditions precede meningitis outbreaks. Vigilance levels objectively defined within the MEWS are consistent with reported cases of meningitis. Alongside developing a MEWS, the co-production process provided a framework for analysis of climate and environmental risks based on reanalysis data, meningitis burden, and health service assessment, to support the development of a qualitative roadmap of country prioritization for defeating meningitis by 2030 across the WHO African region. The roadmap has enabled the identification of countries most vulnerable to meningitis epidemics, and in the context of climate change, supports plans for preventing, preparing, and responding to meningitis outbreaks.

Flight crew fatigue risk assessment for international flights under the COVID-19 outbreak response exemption policy

BackgroundIn response to the COVID-19 outbreak, the Civil Aviation Administration of China (CAAC) has formulated Implementation Measures for Exemption of Crew Duty Periods and Flight Time Restrictions during the COVID-19 Outbreak. This exemption policy imposes temporary deviations from the approved crew duty periods and flight time restrictions for some transport airlines and regulates the use of multiple crews for continuous round-trip flights. However, no research has been conducted on flight crew fatigue under this exemption policy. That is, the exemption policy lacks theoretical analysis and scientific validation.MethodsFirstly, flight plans for international flights under both the exemption and the CCAR-121 Policy schemes (with three flight departure scenarios: early morning, midday and evening) are designed, and flight plans are simulated based on the SAFE model. The Karolinska Sleepiness Scale (KSS) and the PVT objective test of alertness, both of which are commonly used in the aviation industry, are then selected for use in an empirical experimental study of flight crew fatigue on two flights subject to the exemption and CCAR-121 policies.ResultsThe SAFE model simulation found that the fatigue risk results based on flight crews for flights departing in the early morning (4:00), at noon (12:00) and in the evening (20:00) indicate that the fatigue risk levels of flight crews operating under the exemption policy are overwhelmingly lower than or similar to those operating under the CCAR-121 policy. However, there were a few periods when the fatigue risk of crews flying under the exemption policy was higher than that of crews flying under the CCAR-121 policy, but at these times, the crews flying under both policies were either at a lower level of fatigue risk or were in the rest phase of their shifts. In the experimental study section, 40 pilots from each of the early morning (4:00), noon (12:00) and evening (20:00) departures operating under the exemption policy were selected to collect KSS scale data and PVT test data during their duty periods, and a total of 120 other pilots operating under the CCAR-121 policy were selected for the same experiment. First, the KSS scale data results found that flight pilots, whether flying under the exemption policy or under the CCAR-121 policy, had overall similar KSS scores, maintained KSS scores below the fatigue risk threshold (i.e., KSS score < 6) during the flights and that the empirical KSS data and the model simulation results from the KSS data were overall identical at the test nodes during the flight and had nearly identical trends. Finally, the results of the PVT objective test indicators showed that the overall change in 1/RT of the crews flying under the exemption policy was less than or similar to that of the crews flying under the CCAR-121 policy, while the maximum change in 1/RT of the crews under both policies was between 1 and 1.5. This indicates that the overall level of alertness of the crew flying under the exemption policy is higher than or similar to that of the crew flying under the CCAR-121 policy, while the change in alertness level of the crew before and after the mission is relatively small when flying under either policy.ConclusionBased on the model simulation results and the results of the empirical study, it was verified that the overall fatigue risk level of flight crews operating under the exemption policy is lower than or similar to the fatigue risk level of flight crews operating under the CCAR-121 policy. Therefore, the exemption policy in response to the COVID-19 outbreak does not result in an overall increase in the level of flight crew fatigue risk compared to the original CCAR-121 policy.

Perception of the epidemic risks of the COVID-19 pandemic by the population of Ukraine

In the social network Facebook from April 2020 to October 2020 an online survey using the "Google Form" was conducted to study the perception of the COVID-19 pandemic by the residents of Ukraine. The study involved 550 participants residing in the Ukraine-controlled territory and the city of Kyiv. The data are as follows: the coronavirus is considered a serious danger by 33.3±2.0% of respondents and 11.6±1.4% agree with certain doubts (in total – Σ44.9±2.1%); 21.1±1.7% believe that the coronavirus is not serious and 17.3±1.6% believe that it is probably not serious (Σ38,4±2.1%). COVID-19 is recognized as a pandemic by 73.6±1.9% of respondents, of them 45.6±2.1% of respondents completely agree with this statement. Different views towards the severity of the problem show little but reliable correlation with age (rc =0,23; p&lt;0.001), gender (rc =0,21; p&lt;0,001) of the respondents, as well as with the size of the locality where respondents live (rc =0.30; p&lt;0.001). It was revealed that men (47.2±3.6%), persons over 50 years of age (47.5±5.0%) and residents of small towns with a population of 3,000 to 10,0000 residents (47.7±4.3%) are more skeptical about this issue. The majority of respondents have a moderate level of epidemiological vigilance – 299 (54.4±2.1%); this means that a person emphasizes the seriousness and real threats of coronavirus infection, perceives and adheres to the adopted measures, but with certain hesitations. A high level of epidemiological vigilance characterized by confidence in the real situation and the adopted measures is found in 119 (21.6±1.8%) respondents. A low level of epidemiological vigilance is in 121 (22.0±1.8%) res­pon­dents. Only 11 people (2.0±0.6%) have the overall sum of points, which indicates the absence of epidemiological vigilance.

Videogaming Frequency and Executive Skills in Young Adults.

Many studies have shown that “action” videogames (VG) training can improve various cognitive aspects (such as attention, enumeration skill, problem solving, vigilance, inhibitory control and decision making). Unfortunately, independently by VG genre, little research has been conducted on the relevance of videogaming frequency to modulate cognitive performance. In the present study, we investigated the differences between two groups of young adults (Experienced Gamers and Casual Gamers, respectively, EGs and CGs) in some attentional and executive abilities. To this end, 19 EGs (age 23.21 ± 1.68 years; gaming frequency 46.42 ± 11.15 h/week) and 19 CGs (age 23.10 ± 2.28 years; gaming frequency 1.31 ± 1.76 h/week) were selected and asked to complete a computer-based and customized version of an executive battery (i.e., Attention Network Task, Game of Dice task, Go/NoGo task and Task Switching). The results showed better basic attentional abilities and alertness level (i.e., as indicated by faster reaction times (RTs) and greater accuracy) in EGs compared to CGs. Moreover, EGs showed a more efficient decision making than CGs, particularly evident in risky decisions. Taken together, such results show that an executive functioning improvement can be observed as a consequence of continuous and constant exposure to VG, independently by the specific genre played. These data can be a useful starting point to develop new and innovative executive training protocols, based and inspired to videogames to be applied in clinical populations suffering, for example, from dysexecutive impairment.

Urban gulls show similar thermographic and behavioral responses to human shouting and conspecific alarm calls

Rapid population growth and the urbanization of modern environments are markedly increasing human-wildlife conflict. Wild animals in urban landscapes can benefit from exploiting human resources, but are also exposed to increased risk of human-caused injury, which should favor the ability to perceive and respond to human cues. Although it is well known that domesticated animals use human cues that may indicate threats, less is known about wild animals living in urban environments. Herring gulls (Larus argentatus) in urban landscapes have adapted kleptoparasitic behaviors to obtain human food, often resulting in negative interactions with humans. Here we quantified both the behavioral and physiological responses of free-living urban herring gulls to human shouting. We presented urban gulls with a fake human food item and played back recordings of either a man shouting, a natural stressor (i.e., conspecific alarm call), or a neutral stimulus (i.e., robin song). We recorded behavioral responses and used non-invasive infrared thermography to measure eye-region surface temperature changes associated with the avian physiological stress response. We found that gulls exposed to shouting and to conspecific alarm calls showed similar changes in behavior (indicating high levels of vigilance) and eye-region surface temperature (indicating physiological stress). Both responses were significantly stronger than the responses to robin song. Additionally, the behavioral and physiological responses were positively correlated across individuals. Our results demonstrate that urban-dwelling gulls respond to human shouting and conspecific alarm calls in a similar way, and suggest that infrared thermography is a viable technique to monitor stress responses in free-living birds.

Effects of Predator-Driven Prey Dispersal on Sustainable Harvesting Yield

Dispersal of organisms between patches is a common phenomenon in ecology and plays an important role in predator–prey population dynamics. We propose a nonsmooth Filippov predator–prey model in a two-patch environment characterized by a generalist predator-driven intermittent refuge protection of an apprehensive prey along with a balanced dispersal of the prey between refuge and nonrefuge areas. By employing qualitative techniques of nonsmooth dynamical systems, we see that the switching surface is a repeller whenever the interior equilibria are virtual, causing long-term population fluctuations. We find that the level of prey vigilance and the rate of prey dispersal play pivotal roles in the total harvesting yield. We observe that a sustainable high harvesting yield is possible when the prey is less vigilant and obtain the harvesting efforts for maximum sustainable total yield (MSTY). We further modify the model by considering a continuous threshold predator-driven prey dispersal and show that the model exhibits a Hopf bifurcation when the level of prey vigilance exceeds some critical threshold value. By comparing the dynamics of the two models we see that for a sustainable high harvesting yield of the system with continuous threshold dispersal, the prey needs to be highly vigilant compared to that of the system with intermittent dispersal of the prey. Further, we find numerically that the estimated MSTY from both models remains the same.

Law Enforcement Against Street Crimes During a Pandemic That Occurred In Sidoarjo

The purpose of this research is Law Enforcement Efforts Against Street Crime Period in Sidoarjo. The research method used is a normative juridical research method, which focuses on the study starting from the provisions of the applicable laws and regulations, accompanied by legal theories and principles related to the problems studied. The results of the research In carrying out the prevention of street crime, the Sidoarjo City Police made several efforts, namely with Preventive Efforts and Repressive Efforts. The efforts to overcome street crime are carried out by carrying out patrols carried out by the police, the establishment of Tangguh village posts spread across almost all areas from the RT, RW and Village levels, empowerment of Bhabinkamtibmas, involvement of elements related to handling the pandemic (TNI, Regional Government, BPBD), carry out operations to control the completeness of motorized vehicles, with the application the community can easily communicate with the police, and also the police give mandate to the community if a crime occurs so that they can immediately report it to the authorities. And there are also obstacles What is often encountered by the Sidoarjo City Police is that the public does not understand the dangers of the Covid 19 pandemic and its impact on the increase in crime, by ignoring health protocols and decreasing the level of vigilance for the occurrence of crime. The public's rejection of the efforts / policies taken by the government related to the handling of the Covid 19 Pandemic on the grounds that these policies limit the space for people to find sustenance, as well as the limited number of personnel and finances for the deployment of a humanitarian operation.

The Use of Blended Diets in Children With Enteral Feeding Tubes: A Joint Position Paper of the ESPGHAN Committees of Allied Health Professionals and Nutrition.

This joint position paper of the Committees of Allied Health Professionals (CAHP) and Nutrition (CON) of the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) provides a comprehensive guide for health professionals to manage blended diets in children via gastrostomy tubes. A systematic literature search was performed from 1992 to 2021 using Pubmed, MEDLINE, and Cochrane Database of Systematic Reviews and recent guidelines reviewed. In the absence of evidence, recommendations reflect the authors' expert opinion. Final consensus was obtained by multiple e-mail exchange and virtual meetings of the CAHP and CON. Reported benefits of blended diets include reduced GERD and infections, improved defecation, level of alertness and attention span, skin conditions, and appearance of hair and nails. Families report a sense of greater normality. Small case series, cross-sectional surveys, questionnaire-based small case studies, reports of personal experience, and single-center pilot studies are available in the medical literature. A total of 20 recommendations for practice were made based on the results and consensus process. There is little evidence published to formally inform about the potential health benefits or risks of this practice and how to use it in the best way. This leaves health professionals caring for such patients in a relative vacuum regarding what to consider when providing a duty of care to patients and carers who wish to pursue this method of feeding. This article provides guidelines for safe and appropriate use of a BD, but more research is needed.

Physiological Measurements of Vigilance: A Systematic Review

Vigilance is the ability to sustain attention for more than 5 to 10 minutes at a time. Maintaining vigilance over a prolonged duration is challenging, and the ability to do so generally declines over time; This is a phenomenon that is known as “vigilance decrement.” Vigilance decrement is often associated with physiological changes. Although previous studies have examined the relationship between physiological responses and vigilance decrement, the results are inconsistent and the trends are not sufficiently clear. Recognizing the need for a comprehensive overview of the existing results, in this paper, we review the most recent studies focusing on physiological changes as indicators of vigilance decrement. We consider electroencephalography (EEG), electrocardiography (ECG), eye movement, and electromyography (EMG). We present an overview of the overall relationship between these measures and vigilance levels; we also highlight the limitations and challenges of previous studies and provide some insight into future research directions in this field.

Automatic Driver Drowsiness Detection Using Artificial Neural Network Based on Visual Facial Descriptors: Pilot Study.

PurposeDriving while drowsy is a major cause of traffic accidents globally. Recent technologies for detection and alarm within automobiles for this condition are limited by their reliability, practicality, cost, and lack of clinical validation. In this study, we developed an early drowsiness detection algorithm and device based on the “gold standard brain biophysiological signal” and facial expression digital data.MethodsThe data were obtained from 10 participants. Artificial neural networks (ANN) were adopted as the model. Composite features of facial descriptors (ie, eye aspect ratio (EAR), mouth aspect ratio (MAR), face length (FL), and face width balance (FWB)) extracted from two-second video frames were investigated.ResultsThe ANN combined with the EAR and MAR features had the most sensitivity (70.12%) while the ANN combined with the EAR, MAR, and FL features had the most accuracy and specificity (60.76% and 58.71%, respectively). In addition, by applying the discrete Fourier transform (DFT) to the composite features, the ANN combined with the EAR and MAR features again had the highest sensitivity (72.25%), while the ANN combined with the EAR, MAR, and FL features had the highest accuracy and specificity (60.40% and 54.10%, respectively).ConclusionThe ANN with DFT combined with the EAR, MAR, and FL offered the best performance. Our direct driver sleepiness detection system developed from the integration of biophysiological information and internal validation provides a valuable algorithm, specifically toward alertness level.

SYNCHRONOUS GASTROINTESTINAL STROMAL TUMOR AND PHEOCHROMOCYTOMA IN A PATIENT WITH NEUROFIBROMATOSIS TYPE 1:A CASE REPORT

The risk of tumours including pheochromocytoma and gastrointestinal stromal tumour (GIST) has been reported to be higher in neurofibromatosis type 1 (NF1) patients.The co-occurrence of pheochromocytoma and GIST among NF1 patients is rare. In this case report, we describe the case of a sixty-five-year- old woman who presented with abdominal pain. CT imaging revealed two abdominal masses. The patient underwent surgical treatment with no complications and after one year remains in oncological remission. The pheochromocytoma and GIST tumours were diagnosed based on pathology. Here, we discuss the rare association of pheochromocytoma and GIST and the asymptomatic presentation of those tumours in an NF1 patient. We further suggest that in NF1 patients a high level of vigilance can help making early diagnosis.

Attentional asymmetry in orienting and alertness and its relationship to temperament: A longitudinal study of infants aged 6–24 months

Previous research suggests that difficulties in orienting to visual stimuli directed by the right hemisphere are related to parental reports of distress and may be an early sign of autism spectrum disorder (ASD). One possible reason for this difficulty is infants’ ability to achieve high levels of alertness, which also depends on the right hemisphere. This study examines the relationship between phasic alertness and asymmetry in visual orienting in typically-developing 6–24-month-old infants using the overlap paradigm. Participants were given a spatially non-directive warning signal shortly before the onset of the peripheral target. The signal reduced latencies in both overlap and no-overlap conditions. No main effects of age and visual field or interaction were found. However, results confirm the negative association between temperamental soothability and disengagement difficulty toward the left visual field at 6 months. This is discussed from the viewpoint of early left visual field attentional bias in relation to social cognition.

Modulation of thalamic network connectivity using transcranial direct current stimulation based on resting-state functional magnetic resonance imaging to improve hypoxia-induced cognitive impairments.

Hypoxic conditions at high altitudes severely affect cognitive functions such as vigilance, attention, and memory and reduce cognitive ability. Hence, there is a critical need to investigate methods and associated mechanisms for improving the cognitive ability of workers at high altitudes. This study aimed to use transcranial direct current stimulation (tDCS) to modulate thalamic network functional connectivity to enhance cognitive ability. We recruited 20 healthy participants that underwent hypoxia exposure in a hypoxic chamber at atmospheric pressure to simulate a hypoxic environment at 4,000 m. Participants received both sham and real stimulation. tDCS significantly improved the participants’ emotional status, including depression, fatigue, and energy level. These effects were sustained for more than 6 h (P < 0.05 at the second to fifth measurements). In addition, tDCS enhanced vigilance, but this was only effective within 2 h (P < 0.05 at the second and third measurements). Central fatigue was significantly ameliorated, and cerebral blood oxygen saturation was increased within 4 h (P < 0.05 at the second, third, and fourth measurements). Furthermore, functional connectivity results using the thalamus as a seed revealed enhanced connectivity between the thalamus and hippocampus, cingulate gyrus, and amygdala after tDCS. These results indicated that tDCS increased local cerebral blood oxygen saturation and enhanced thalamic network connectivity in a hypoxic environment, thereby improving vigilance, depression, fatigue, and energy levels. These findings suggest that tDCS may partially rescue the cognitive decline caused by hypoxia within a short period. This approach affords a safe and effective cognitive enhancement method for all types of high-altitude workers with a large mental load.

Goitered Gazelle Gazella subgutturosa Responded to Human Disturbance by Increasing Vigilance Rather than Changing the Group Size.

Simple SummaryWild animals perceive nonlethal human activities as a potential threat, and they respond to human disturbances in a variety of ways: changes in group size and time-investment on vigilance are common behaviors. In China, nature reserves are generally divided into three functional zones: the core zone, the buffer zone, and the experimental zone, which represent low, medium, and high human disturbance levels, respectively. However, mining developments in the three zones pose threats to goitered gazelle living in the Kalamaili Nature Reserve, China. In this study, we found that human disturbances have larger effects on smaller-sized, single-sex groups rather than larger-sized, mixed-sex groups. Goitered gazelle spend more time being vigilant in the experimental zone than in the other two zones. In the experimental zone, a greater linear decrease with respect to group size was observed. Our results indicate that intensive human disturbances in the core and buffer zones brought goitered gazelle and humans closer together, which induced changes in vigilance and grouping patterns of this social species. Ultimately, this may have negative effects on the fitness and survival of the species.Nonlethal human disturbances have been confirmed to have a negative effect on wildlife in a variety of ways, including on behaviors. In many studies, the impact of human disturbances on gregarious species of wildlife is assessed through changes in their social organization and vigilance. In our study in the Kalamaili Nature Reserve, China, we wanted to estimate the impacts of differing levels of human disturbances on two different group types (mixed-sex and all-male) of goitered gazelle, Gazella subgutturosa, living in three functional zones (experimental, buffer, and core zones), which represent high, medium, and low human disturbance levels, respectively. In addition, we studied the time spent vigilant as a function of group size with different levels of human disturbances in the three zones. In general, mixed-sex gazelle groups were of similar sizes in the three different zones, while all-male groups slightly differed in their sizes between the experimental and buffer zones. This may indicate that human disturbances have varying effects on the different group types, with smaller-sized, single-sex groups being more significantly affected by human disturbances than larger-sized, mixed-sex groups. Goitered gazelle showed higher vigilance levels in the experimental zone than in the two other zones. A trend of decreasing vigilance varying linearly with group size was also found in the three zones, and the rate of decrease was higher in the experimental zone. Increased habitat fragmentation and human activities brought goitered gazelle and humans closer together in the core zone. Therefore, stopping mining activities and returning the reserve to a continuous habitat with fewer environmental disturbances is the best way to establish and protect a stable population of this endangered species of gazelle.

Effects of caffeine, methylliberine, and theacrine on vigilance, marksmanship, and hemodynamic responses in tactical personnel: a double-blind, randomized, placebo-controlled trial

ABSTRACTBackgroundTactical athletes require fast reaction times (RT) along with high levels of vigilance and marksmanship performance. Caffeine has been shown to improve these measures but also results in increased blood pressure and jitteriness. Research on other purine alkaloids, such as methylliberine and theacrine, has suggested they do not increase blood pressure or jitteriness to the same extent, but their impact on tactical performance is unknown.MethodsA between-subjects, randomized, placebo-controlled design was used to test the effects of placebo (PLA), 300 mg caffeine (CAF), and a combination of 150 mg caffeine, 100 mg methylliberine, and 50 mg theacrine (CMT) on RT and marksmanship along with hemodynamic and arousal measures following a sustained vigilance task in tactical personnel (n = 48). Following consumption of the supplement, participants underwent a 150-min protocol consisting of two rounds. Each round began with leisurely reading followed by a 30-min vigilance task before beginning two trials of movement and marksmanship tasks. Hemodynamics and felt arousal were assessed throughout the protocol. Composite Z-scores were calculated for overall performance measures at each timepoint, and mixed-effects models were used to assess differences in RT, accuracy, and composite Z-scores along with hemodynamics and felt arousal. An α-level of 0.05 was used to determine statistical significance, and Cohen’s d was used to quantify effect sizes.ResultsA Group-by-Time interaction for vigilance RT (P = 0.038) indicated improvements for both CAF and CMT from round 1 to round 2 (P < 0.01) while PLA did not change (P = 0.27). No Group main effects or Group-by-Time interactions were found for movement or marksmanship performance (P > 0.20). Group main effects for systolic (SBP; P = 0.001) and diastolic blood pressure (DBP; P = 0.028) indicated higher SBP in CAF (P = 0.003, d= 0.84) and CMT (P = 0.007, d= 0.79) compared to PLA but only higher DBP in CAF (P = 0.025, d= 0.74). No Group-by-Time interaction or Group main effect was found for felt arousal (P > 0.16).ConclusionsThese findings suggest similar benefits on RT during a vigilance task between CAF, containing 300 mg caffeine, and CMT above PLA, though CAF resulted in slightly less favorable hemodynamic changes. This study is the first to provide data showing similar efficacy of combined caffeine, methylliberine, and theacrine compared to double the caffeine dose consumed alone on vigilance RT but without a significant rise in DBP above PLA in tactical personnel.

Clinical investigation of sensing ailments in brain movement through physiological activity using ML technique

The main goal was to demonstrate that EEG and its derivatives may be utilised to recreate brain function using EEG data. This is vital to determine the application's source activities in order to assess various strategies that address the reverse issue, hence accessibility to a standardized EEG dataset is essential. Physiological and psychological tests could be used to determine alertness or activity levels in particular. Furthermore, changes of psychological measurements can be influenced by a variety of cognitive notions. Heartbeat, skin temperature, and brainwaves activities, in example, were susceptible to several psychological categories such as sleepiness, tension, and so on. EEG, on the other hand, delivers a robust resolving power and continuous recording the cerebral activity. An EEG records either periodic and irregular brainwaves. ML approaches are used to classify the physical movement of the heart brain per its condition. The main purpose is using categorization to improve the effectiveness of testing condition segmentation. Multimodal modeling, which is built upon localised machine learning, is a rather appealing option to bipolar neuroimaging, particularly in terms of increased sensibility to alterations in experiment settings.

La somnolence chez les adolescents: étiologie et conséquences multiples

Over the past century a dramatic decline in sleep duration among adolescents, such as more than one hour of sleep loss per night, has been reported. A debt in sleep duration could lead to sleep deprivation, a major risk factor associated with daytime sleepiness. Sleepiness refers to the inability to maintain an adequate level of alertness during the day which may result in more or less being able to control falling asleep at inappropriate times. This literature review updates on sleepiness regarding its characteristics, etiology and consequences on adolescents. Studies revealed that from 25 % to 78 % of adolescents had reported sleepiness. Its manifestations may include heavy lids, yawns, difficulties to concentrate and emotional irritability. In addition, while it is recommended that adolescents under 18 years-old should sleep from eight to ten hours a night, only 63 % of them actually do so. The etiology of sleep deprivation and sleepiness in this population can be explained by various biological and societal factors. First, the sleep-wake cycle of adolescents shows a biological shift from the beginning of pubertal maturation, described as a perfect storm. It refers to a social jetlag by going to sleep and waking up later and accumulating a sleep debt during weekdays which they try to reimburse during weekends. This phenomenon can be explained by physiological changes such as a slower accumulation of sleep pressure. In addition to this perfect storm, environmental and societal factors contribute to the social jetlag and reduce sleep duration in adolescents. Screen exposure before bedtime can delay sleep and wake onset, which is a risk factor for sleeping debt. Substance use such as caffeine, cigarettes or electronic vaporizer, ADHD or freely available medication, alcohol, cannabis use or drug consumption could further disrupt sleep-wake cycle by stimulating, depressing or otherwise disrupting the central nervous system. Early, before 8:30 am, class start times have been associated with chronic sleep deprivation, higher level of sleepiness and delayed melatonin peak secretion. Adolescents working or doing extracurricular occupations for more than 20hours a week are more at risk for reduced sleep duration and sleepiness. Parental supervision about sleep during the weekdays were associated with more appropriate bedtime. Adolescents from low socio-demographic characteristics and from minority ethnic groups have reported displaying a shorter sleep duration. Finally, sleep disorders of a physiological origin such as narcolepsy, sleep apnea or restless legs syndrome, may explain the sleep deprivation and sleepiness. Sleep deprivation and sleepiness in adolescents have consequences on their health. Cognitive functioning, such as problem solving, attention or memory, as well as school performance, can be compromised by sleep deprivation and sleepiness. At the psychological level, adolescents reporting sleepiness are more prone to display mental health problems: associations were found between sleepiness and subjective perception of depression, anxiety, somatic complaints as well as with antisocial behaviors. Finally, 68 % of 16 year-old adolescents reported they drove a car, and the reported sleepiness could lead to road accidents due to reduced attentional functioning, reaction time and decision-making abilities. In the United-States, from 7 % to 16.5 % of deadly accidents were related to driving while drowsy. Highlighting etiology and problems associated with sleep deprivation and sleepiness in adolescents could guide researchers and clinicians towards the development of possible interventions. Public health measures and knowledge transfer programs regarding modifiable psychosocial and societal factors associated with sleep-wake bioregulation could increase awareness in parents as well as in political and societal decision makers.

Dynamics in the biparametric spaces of a three-species food chain model with vigilance

In nature, vigilance is a common anti-predator strategy prey individuals employ to protect themselves from a possible attack. It gives them sufficient time to take cover or flee. Yet this seemingly profitable strategy, which lowers the number of successful predatory attacks, has a significant impact on the prey's growth rate. Researchers attribute this to reduced foraging time. In this article, we study a three-species food chain model in which both the basal prey and middle predator show active vigilance against their respective predators. Apart from the positivity, boundedness, and local stability analysis of the equilibrium points of the model, we find the conditions for global stability and the occurrence of Hopf bifurcation around the coexisting equilibrium point. Bifurcation diagrams and their corresponding Lyapunov exponent diagrams (largest and second-largest) illustrate diverse dynamical scenarios ranging from stable coexistence to periodic to chaotic oscillations. The isospike diagrams and their associated largest Lyapunov exponent diagrams in the biparametric space of basal prey's and middle predator's vigilance reveal a broader picture of the effects of different levels of vigilance on the dynamics of the system. A great deal of attention has been paid to unwrapping the complex structural beauties like shrimp-shaped periodic structures inside the chaotic sea and multistability between several sets of attractors in the overlapping zones of periodic windows. We observe that multiple coexisting attractors possess fractal basin boundaries. We also explore the dynamics of the system in two other biparametric spaces. The density variation maps at the end show the effect of vigilance on the equilibrium density of all three species. Our results suggest that vigilance promotes regularity and coexistence, but too high levels of vigilance can cause species extinction. For better visualization of the system dynamics, we provide a few high-resolution animations of the phase portraits and the basins of attraction in the supplementary material.

A Theory of Crime and Vigilance

This paper develops a theory of crime in which potential victims elect their vigilance levels. When vigilance expenses are greater than expected property losses, an increase in penalties raises crime, namely, a criminal Laffer curve emerges. This curve is higher and peaks earlier when victims face higher costs. Thus, the government may wish to subsidize vigilance rather than increase penalties. Indeed, an increase in penalties may shift the vigilance levels further away from their socially optimal ones. Finally, the crime rate first rises and then falls in the property value at stake, which is consistent with the empirical evidence. (JEL D91, H76, K42)

Institutional Support for Entrepreneurship and New Venture Internationalization

We build on institutional theory to predict that (1) home country institutional support for entrepreneurship promotes new venture internationalization, (2) entrepreneurial alertness positively impacts this relationship, and (3) political ties negatively impact the moderating effect of entrepreneurial alertness. We confirm our hypotheses with two sets of primary data collected in the emerging economy of Ghana. We conclude that home country institutional support for entrepreneurship exhibits the strongest effect on new venture internationalization for founders with higher levels of entrepreneurial alertness and weaker political ties.