Estimation of the spectral measure of multivariate regularly varying distributions

In the paper, the estimator for the spectral measure of multivariate stable distributions introduced by Davydov and co-workers are extended to the regularly varying distributions. The sampling method is modified to optimize the rate of convergence of estimator. An estimator of the total mass of spectral measure is proposed. The consistency and the asymptotic normality of estimators are proved.Comment: 23 pages, 3 figure

Illustration par quelques exemples des lois strictement stables dans un c\^one convexe

The stability of random variables can be generalized in any convex cone. In this case the principal results about the LePage representation and the domains of attraction are analogous but different to those well known for general Banach spaces. Some examples of strictly stable distributions and max-stable distributions are presented in this paper in order to exhibit the relationship between the Poisson process and the stable distributions on convex cones.Comment: 24 pages, 5 figures, in Frenc

Positive and negative experiences with the COVID-19 pandemic among lonely and non-lonely populations in Germany

The COVID-19 pandemic is causing an epidemic of loneliness. Previous studies have shown the differences in positive and negative experiences of lonely and non-lonely people in a non-pandemic setting. However, it is unclear how the drastic alteration of the COVID-19 pandemic may influence peoples' reactions and beliefs, especially among those who feel lonely. Our study aims to examine the positive and negative experiences among lonely and non-lonely people. We undertook a cross-sectional online survey of the general population in Germany (N = 1,758) from May 2020 to May 2022. We assessed their feelings of loneliness with the short eight-item UCLA Loneliness Scale (ULS-8), their positive and negative experience of living in the COVID-19 pandemic as well as their psychological distress regarding the pandemic with the COVID-19 Peritraumatic Distress Index (CPDI). We found lonely individuals (ULS-8 score ≥ 16) reported fewer positive experiences of living in the COVID-19 pandemic, for example, less time with loved ones [z(1,756) = −2.5, p = 0.012] and less sense of togetherness [z(1,756) = −2.39, p = 0.017] as compared to non-lonely individuals. Meanwhile, they experienced more negative experiences, for example, worry and fear [z(1,756) = 6.31, p < 0.001] compared with non-lonely individuals. Interestingly, lonely people were less likely to view the pandemic as a conspiracy than non-lonely people were [z(1,756) = −3.35, p < 0.001]. Our results may give insight into attribution bias and the negative affect of lonely people during the COVID-19 pandemic as well as highlight the experience of non-lonely people and raise the question of differences in conspiracy beliefs. For pandemic preparedness and response, decision-makers may focus on interventions to foster social cohesion, empower people, build resilience, and most importantly provide timely social care

The Persistence of The Impact of COVID-19-Related Distress, Mood Inertia and Loneliness on Mental Health During a Postlockdown Period in Germany: An Ecological Momentary Assessment Study

Background: The first wave of the COVID-19 pandemic in early 2020 increased mental health problems globally. However, little is known about mental health problems during a low-incidence period of the pandemic without strict public health measures. Objective: We aim to investigate whether COVID-19-related risk factors for mental health problems persist beyond lockdown measures. We targeted a vulnerable population that is at risk of developing low mental health and assessed their daily dynamics of mood and emotion regulation after a strict lockdown. Methods: During a postlockdown period in Germany (between August 8, 2020, and November 1, 2020), we conducted an ecological momentary assessment with 131 participants who experienced at least mild COVID-19-related distress and loneliness. To estimate negative mood inertia, we built a lag-1 three-level autoregressive model. Results: We found that information exposure and active daily COVID-19 cases did not have an impact on negative mood amid a postlockdown period. However, there was a day-to-day carryover effect of negative mood. In addition, worrying about COVID-19, feeling restricted by COVID-19, and feeling lonely increased negative mood. Conclusions: The mental health of a vulnerable population is still challenged by COVID-19-related stressors after the lifting of a strict lockdown. This study highlights the need to protect mental health during postpandemic periods

The Impact of COVID-19 Lockdown on Daily Activities, Cognitions, and Stress in a Lonely and Distressed Population: Temporal Dynamic Network Analysis

Background: The COVID-19 pandemic and its associated lockdown measures impacted mental health worldwide. However, the temporal dynamics of causal factors that modulate mental health during lockdown are not well understood. Objective: We aimed to understand how a COVID-19 lockdown changes the temporal dynamics of loneliness and other factors affecting mental health. This is the first study that compares network characteristics between lockdown stages to prioritize mental health intervention targets. Methods: We combined ecological momentary assessments with wrist-worn motion tracking to investigate the mechanism and changes in network centrality of symptoms and behaviors before and during lockdown. A total of 258 participants who reported at least mild loneliness and distress were assessed 8 times a day for 7 consecutive days over a 213-day period from August 8, 2020, through March 9, 2021, in Germany, covering a “no-lockdown” and a “lockdown” stage. COVID-19–related worry, information-seeking, perceived restriction, and loneliness were assessed by digital visual analog scales ranging from 0 to 100. Social activity was assessed on a 7-point Likert scale, while physical activity was recorded from wrist-worn actigraphy devices. Results: We built a multilevel vector autoregressive model to estimate dynamic networks. To compare network characteristics between a no-lockdown stage and a lockdown stage, we performed permutation tests. During lockdown, loneliness had the highest impact within the network, as indicated by its centrality index (ie, an index to identify variables that have a strong influence on the other variables). Moreover, during lockdown, the centrality of loneliness significantly increased. Physical activity contributed to a decrease in loneliness amid the lockdown stage. Conclusions: The COVID-19 lockdown increased the central role of loneliness in triggering stress-related behaviors and cognition. Our study indicates that loneliness should be prioritized in mental health interventions during lockdown. Moreover, physical activity can serve as a buffer for loneliness amid social restrictions

Long-Term Impact of Economic Downturn and Loneliness on Psychological Distress: Triple Crises of COVID-19 Pandemic

Background: The COVID-19 crisis poses global mental health and global economy challenges. However, there is a lack of longitudinal research investigating whether financial instability and social disruption may increase the risk of developing mental health problems over time that may potentially outlast the pandemic. Methods: We conducted an online survey for members of the general population (n = 2703) in Germany during the twelve months spanning from April 2020 to March 2021. We investigated the development of COVID-19 related psychological distress, the number of unemployed people, federal government debt, income distribution, and loneliness over the time period. Results: Over a period of twelve months, 53.6% of respondents in Germany reported experiencing psychological distress, varying from mild levels, 34.2%, to severe levels, 19.4%, of distress. High federal government debt, high incident COVID-19 cases, low incomes, and the prevalence of loneliness were found to be associated with increased long-term mental health problems. Psychological distress scores were most strongly increased in female and young respondents as well as those who reported fewer years of education, low income, and higher loneliness. Conclusions: Our study highlights factors that have a long-term impact on mental health amid the COVID-19 pandemic. We suggest that specific mental-health services could be offered to support high-risk groups experiencing financial fragility and loneliness. For purposes of safeguarding their mental health there is a need to monitor and track such risk factors in real time

Increased Psychological Distress, Loneliness, and Unemployment in the Spread of COVID-19 over 6 Months in Germany

Background: The COVID-19 pandemic poses a challenge to global mental health. Loneliness and isolation may put people at higher risk for increased psychological distress. However, there is a lack of research investigating the development of COVID-19-related distress over time. Materials and Methods: We undertook an online survey among general population (N = 1903) in Germany throughout 6 months from the peak transmission period in April to the off-peak period by September 2020. Results: We found that the average prevalence of psychological distress caused by the COVID-19 pandemic significantly rose from 24% to 66% between the peak and off-peak transmission period, respectively. Unemployment rate and loneliness increased negative mental health outcomes, although the number of active COVID-19 cases decreased from April to September. Psychological distress scores increased mostly in female, young, and lonely people. Conclusions: Our results underline the importance of considering innovative alternatives to facilitate employment opportunities, distant contacts, and self-help over the course of the pandemic. Our study highlights the urgent need to pay attention to mental health services specifically targeting female, young, unemployed, and lonely people

Du dialecte à la langue internationale : Etude sociolinguistique du français

Ce texte vise à étudier le statut du français en évolution dans le temps et dans l’espace. Il s’agit d’analyser sa fonction à titre de langue vernaculaire et de langue véhiculaire, son rapport au latin et à d’autres dialectes territoriaux ainsi que son état de défense surtout face à l’anglais et son avenir passant par le combat pour la diversité culturelle