The association of sleep and stress with psychological well-being and neuronal functional connectivity

Sufficient sleep and an adequate stress response are two important components when it comes to coping with adverse events. Previous studies have shown that both are related to the occurrence of psychological and physical disorders, emphasizing the necessity to explore both concepts within the scope of this PhD thesis individually as well as their association among each other. In Study 1, we investigated the association of sleep-related variables with psychological well-being based on an online survey. We found evidence that the association of psychological well-being towards chronotype follows a U-shaped function, which means that being an early or late chronotype is related to impaired well-being. Additionally, reduced sleep durations, especially when occurring on work days, was associated with depressive symptomatology and sleep quality. For Study 2 and 3 we deployed neuroimaging data, as both sleep deprivation and psychosocial stress have been proven to change neuronal activity and connectivity patterns in the aftermath of stress. Study 2 focused on replicating results concerning the previously reported increased connectivity of the amygdala with regions involved in the down-regulation of the physiological stress response, in emotion regulation, and in memory consolidation. Analyzing resting state connectivity after stress compared to the pre-stress condition, we found an increase in bilateral amygdala resting-state functional connectivity (RSFC) with the posterior cingulate cortex (PCC) and the adjacent precuneus only in male cortisol non-responders, but not in responders. We did not detect changes in amygdala RSFC between female cortisol responders and non-responders. This finding shows the influence of sex and cortisol reactivity, when exploring neural signatures of stress reactivity and recovery. In Study 3 we focused on male participants only, now expanding the results from Study 2 by exploring the impact of sleep loss on neural signatures of stress recovery. We found a negative association of sleep loss, as reported in a seven-day sleep diary, with the stress-induced change of left amygdala RSFC to several cortical brain regions, including the medial prefrontal cortex, dorsolateral prefrontal cortex, dorsal anterior cingulate cortex, anterior insula, and PCC. That is, the higher the sleep loss, the more decrease in left amygdala RSFC was found with these regions after stress. Taken together, the results of this PhD thesis contribute to a better understanding of associations between sleep, stress, and psychological well-being on a behavioral as well as neuronal level.Ausreichend Schlaf und eine angemessene Stressantwort stellen zwei wichtige Faktoren im Umgang mit belastenden Ereignissen dar. Frühere Studien berichteten von einem Zusammenhang mit dem Auftreten von psychologischen und physischen Erkrankungen. Dies belegt die Notwendigkeit, deren Wirkung im Rahmen der vorliegenden Doktorarbeit sowohl als einzelne Konstrukte als auch in Verbindung zueinander zu explorieren. Im Rahmen der ersten Studie untersuchten wir den Zusammenhang von schlafbezogenen Variablen zu psychologischem Wohlbefinden mithilfe einer Online Umfrage. Die Ergebnisse zeigten, dass der Zusammenhang zwischen psychologischem Wohlbefinden und Chronotyp einer u-förmigen Funktion folgt. Damit haben vor allem sehr frühe und späte Chronotypen ein erhöhtes Risiko für vermindertes Wohlbefinden. Zusätzlich fanden wir, dass eine reduzierte Schlafdauer, vor allem an Arbeitstagen, mit vermehrten depressiven Symptomen und geringerer Schlafqualität assoziiert war. Für die anderen beiden Studien setzten wir bildgebende Verfahren (funktionelle Magnetresonanztomografie) ein, da sowohl Schlafmangel als auch psychosozialer Stress nachweislich einen Einfluss auf die neuronale Aktivität und funktionelle Konnektivität während der Erholung von Stress haben. In Studie 2 konzentrierten wir uns auf die Replikation von früheren Studienergebnissen, die eine stressbedingte Steigerung der Konnektivität zwischen der Amygdala und Gehirnregionen fanden, die in die Herabregulation der physiologischen Stressantwort, in die emotionale Antwort, und die Gedächtniskonsolidierung involviert sind. In der Phase nach einem Stressor fanden wir im Vergleich zu vor dem Stressor eine gesteigerte bilaterale Konnektivität der Amygdala zum posterioren cingulären Cortex (PCC) und dem angrenzenden Precuneus nur in männlichen Teilnehmern ohne Cortisolreaktion im Vergleich zu männlichen Teilnehmern mit einer Cortisolreaktion. Bei weiblichen Teilnehmerinnen fanden sich keine Unterschiede in funktioneller Konnektivität. Die Ergebnisse unterstreichen die Relevanz von Geschlecht und Cortisolraktion beim Betrachten der Erholungsphase nach Stress. Studie 3 erweitert die Ergebnisse aus Studie 2, indem nur bei männlichen Teilnehmern zusätzlich den Einfluss von Schlafmangel auf die neuronale Erholung von Stress untersuchten. Die Auswertung zeigte eine negative Assoziation zwischen Schlafmangel, der in einem siebentägigen Tagebuch festgehalten wurde, und der stressbedingten funktionelle Konnektivtät der linke Amygdala zu mehreren Gehirnregionen, u.a. dem medialen Präfrontalcortex, dem dorsolateralen Präfrontalcortex, dem dorsalen anterioren cingulären Cortex, der anterioren Insula, und dem PCC. Das bedeutet, je mehr Schlafmangel berichtet wurde, desto schwächer war die funktionelle Konnektivität der linken Amygdala zu den genannten Regionen. Zusammengefasst tragen die Ergebnisse der Doktorarbeit zu einem besseren Verständnis des Zusammenhangs von Schlaf, Stress und psychologischem Wohlbefinden auf sowohl Verhaltens. als auch neuronaler Ebene bei

Differences in neural recovery from acute stress between cortisol responders and non-responders

Adaptive recovery from a stressor fosters resilience. So far, however, few studies have examined brain functional connectivity in the aftermath of stress, with inconsistent results reported. Focusing on the immediate recovery from psychosocial stress, the current study compared amygdala resting-state functional connectivity (RSFC) before and immediately after psychosocial stress between cortisol responders and non-responders. Differences between groups were expected for amygdala RSFC with regions involved in down-regulation of the physiological stress response, emotion regulation, and memory consolidation. Eighty-six healthy participants (36 males/50 females) underwent a social stress paradigm inside the MRI scanner. Before and immediately after stress, resting-state (RS) fMRI scans were acquired to determine amygdala RSFC. Next, changes in connectivity from pre- to post-stress were compared between cortisol responders and non-responders. Responders demonstrated a cortisol increase, higher negative affect, and decreased heart rate variability (HRV) in response to stress compared to non-responders. A significant Sex-by-Responder-by-Time interaction was found between the bilateral amygdala and posterior cingulate cortex (PCC) and precuneus (p < 0.05, corrected). As males were also more likely to show a cortisol increase to the stress task than females, follow-up analyses were conducted for both sexes separately. Whereas no difference was observed between female responders and non-responders, male non-responders showed an increase in FC after stress between the bilateral amygdala and the PCC and precuneus (p < 0.05, corrected). The increased coupling of the amygdala with the PCC/precuneus, a core component of the default mode network (DMN), might indicate an increased engagement of the amygdala within the DMN directly after stress in non-responders. Although this study was carried out in healthy participants, and the results likely reflect normal variations in the neural response to stress, understanding the mechanisms that underlie these variations could prove beneficial in revealing neural markers that promote resilience to stress-related disorders

Chronotype is associated with psychological well-being depending on the composition of the study sample

Past studies examining the effect of chronotype and social jetlag on psychological well-being have been inconsistent so far. Here, we recruited participants from the general population and enquired about their natural sleeping behavior, sleep quality, depressive symptoms, and perceived stress. Partial correlations were computed between sleep variables and indicators of psychological well-being, controlling for age and sex. Less sleep during work days was found a good indicator for impairments in psychological well-being. In exploratory follow-up analyses, the same correlations were calculated within groups of early, intermediate, and late chronotype. We observed that the composition of the sample in terms of chronotype influenced whether associations between sleep variables and psychological well-being could be observed, a finding that is advised to be taken into account in future studies.Peer Reviewe

Psycho-social factors associated with mental resilience in the Corona lockdown.

The SARS-CoV-2 pandemic is not only a threat to physical health but is also having severe impacts on mental health. Although increases in stress-related symptomatology and other adverse psycho-social outcomes, as well as their most important risk factors have been described, hardly anything is known about potential protective factors. Resilience refers to the maintenance of mental health despite adversity. To gain mechanistic insights about the relationship between described psycho-social resilience factors and resilience specifically in the current crisis, we assessed resilience factors, exposure to Corona crisis-specific and general stressors, as well as internalizing symptoms in a cross-sectional online survey conducted in 24 languages during the most intense phase of the lockdown in Europe (22 March to 19 April) in a convenience sample of N = 15,970 adults. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience (p < 0.0001). The resilience factor PAS also partly mediated the positive association between perceived social support and resilience, and its association with resilience was in turn partly mediated by the ability to easily recover from stress (both p < 0.0001). In comparison with other resilience factors, good stress response recovery and positive appraisal specifically of the consequences of the Corona crisis were the strongest factors. Preregistered exploratory subgroup analyses (osf.io/thka9) showed that all tested resilience factors generalize across major socio-demographic categories. This research identifies modifiable protective factors that can be targeted by public mental health efforts in this and in future pandemics

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe