161 research outputs found
Doubly forbidden second-harmonic generation from isotropic suspensions: Studies on the purple membrane of Halobacteriumhalobium
The defect variance of random spherical harmonics
The defect of a function is defined as the
difference between the measure of the positive and negative regions. In this
paper, we begin the analysis of the distribution of defect of random Gaussian
spherical harmonics. By an easy argument, the defect is non-trivial only for
even degree and the expected value always vanishes. Our principal result is
obtaining the asymptotic shape of the defect variance, in the high frequency
limit. As other geometric functionals of random eigenfunctions, the defect may
be used as a tool to probe the statistical properties of spherical random
fields, a topic of great interest for modern Cosmological data analysis.Comment: 19 page
On the transience of stability of subthreshold psychopathology
Symptoms of psychopathology lie on a continuum ranging from mental health to psychiatric disorders. Although much research has focused on progression along this continuum, for most individuals, subthreshold symptoms do not escalate into full-blown disorders. This study investigated how the stability of psychopathological symptoms (attractor strength) varies across severity levels (homebase). Data were retrieved from the TRAILS TRANS-ID study, where 122 at-risk young adults (mean age 23.6 years old, 57% males) monitored their mental states daily for a period of six months (± 183 observations per participant). We estimated each individual’s homebase and attractor strength using generalized additive mixed models. Regression analyses showed no association between homebases and attractor strengths (linear model: B = 0.02, p = 0.47, R(2) < 0.01; polynomial model: B < 0.01, p = 0.61, R(2) < 0.01). Sensitivity analyses where we (1) weighed estimates according to their uncertainty and (2) removed individuals with a DSM-5 diagnosis from the analyses did not change this finding. This suggests that stability is similar across severity levels, implying that subthreshold psychopathology may resemble a stable state rather than a transient intermediate between mental health and psychiatric disorder. Our study thus provides additional support for a dimensional view on psychopathology, which implies that symptoms differ in degree rather than kind
The cascade of stress:A network approach to explore differential dynamics in populations varying in familial risk for psychosis
Anticipating Transitions in Mental Health in At-Risk Youths:A 6-Month Daily Diary Study Into Early-Warning Signals
If psychopathology behaves like a complex dynamic system, sudden onset or worsening of symptoms may be preceded by early-warning signals (EWSs). EWSs could thus reflect personalized warning signals for impending psychopathology. We empirically investigated this hypothesis in at-risk youths (N = 122, mean age = 23.6 ± 0.7 years, 57% males) from the clinical cohort of Tracking Adolescents’ Individual Lives Survey (TRAILS-CC), who provided daily emotion assessments for 6 months. We analyzed whether EWSs (rising autocorrelations and standard deviations in emotions) preceded transitions toward psychopathology. Across indicators and a range of analytical options, EWSs had low sensitivity (M = 26%, SD = 11%) and moderate specificity (M = 75%, SD = 14%). Thus, in the present sample, the proposed generic nature and clinical utility of EWSs could not be substantiated. Given this finding, we call for a more nuanced view on the application of complex-dynamic-systems principles to psychopathology and lay out key questions to be addressed in the future
Mild psychotic experiences among ethnic minority and majority adolescents and the role of ethnic density
Despite evidence of the increased risk of psychotic disorders among ethnic minority adults, little is known about the effect of ethnic minority status to mild psychotic experiences among adolescents. This study investigated mild psychotic experiences in ethnic minority and majority adolescents in a Dutch representative general population sample, and tested the ethnic density effect in the classroom.The CAPE was used to assess mild psychotic experiences among Dutch (n = 3,606) and non-Western ethnic minority pupils (n = 769).Ethnic minority adolescents showed higher levels of grandiosity and delusions than their ethnic majority peers, whereas no differences were found for hallucinations, paranormal beliefs and paranoia between both groups of adolescents. The ethnic density effect was partly confirmed for the ethnic majority: a decrease of ethnic majority pupils in class increased their feelings of paranoia.Because only some dimensions of mild psychotic experiences were affected by ethnic minority status or the interaction between ethnic minority status and ethnic class composition, our findings emphasize that mild psychotic experiences are multifactorial in origin, with different underlying processes.</p
The Associations of Affection and Rejection During Adolescence with Interpersonal Functioning in Young Adulthood:A Macro- and Micro-Level Investigation Using the TRAILS TRANS-ID Study
Affection and rejection in close relationships during adolescence are thought to impact adult interpersonal functioning, but few studies focused on how the quality of adolescents' relationships with different people (e.g. parents, peers, and teachers) impacts the daily, micro-level social experiences as well as general, macro-level interpersonal functioning in young adulthood. The present study investigated the associations between: (i) parental, teacher and peer affection and rejection during adolescence and macro-level (over several months) interpersonal functioning as well as different patterns (i.e. mean, variability and inertia) of micro-level (daily social experiences) during young adulthood; (ii) macro-level interpersonal functioning and the patterns of micro-level social experiences during young adulthood. The sample consisted of N = 122 (43% female) youth. At 11.2 +/- 0.4 and 16.0 +/- 0.6 years old, self- and other-reported parental, peer and teacher affection and rejection were assessed. At 23.7 +/- 0.6 years old, participants reported daily social experiences and interpersonal functioning across six months. The results suggested that: (i) higher teacher-reported peer rejection was associated with lower macro-level interpersonal functioning, higher means and higher variability in negative social experiences during adulthood; (ii) higher macro-level interpersonal functioning during young adulthood was associated with higher means and lower inertia in positive and lower variability in negative daily social experiences. These findings indicate that the affection and rejection during adolescence impact interpersonal functioning at macro- and micro-level during adulthood. The present study also shows distinct associations between macro-level interpersonal functioning and dynamics in daily social experiences
The added value of daily diary data in 1- and 3-year prediction of psychopathology and psychotic experiences in individuals at risk for psychosis
This study aimed to assess whether adding information on psychological experiences derived from a daily diary to baseline cross-sectional data could improve short- (1-year) and long-term (3-years) prediction of psychopathology and positive psychotic experiences (PEs). We used 90-day daily diary data from 96 individuals in early subclinical risk stages for psychosis. Stepwise linear regression models were built for psychopathology and PEs at 1- and 3-years follow-up, adding: (1) baseline questionnaires, (2) the mean and variance of daily psychological experiences, and (3) individual symptom network density. We assessed whether similar results could be achieved with a subset of the data (7-14- and 30-days). The mean and variance of the diary improved model prediction of short- and long-term psychopathology and PEs, compared to prediction based on baseline questionnaires solely. Similar results were achieved with 7-14- and 30-day subsets. Symptom network density did not improve model prediction except for short-term prediction of PEs. Simple metrics, i.e., the mean and variance from 7 to 14 days of daily psychological experiences assessments, can improve short- and long-term prediction of both psychopathology and PEs in individuals in early subclinical stages for psychosis. Diary data could be a valuable addition to clinical risk prediction models for psychopathology development.</p
The dynamic relationship between sleep and psychotic experiences across the early stages of the psychosis continuum
Ecology of the Missouri River: Missouri River Creel Survey, Bellevue Bridge to Camp Creek, 3 April through 29 May 2004
The Nebraska Game and Parks Commission\u27s strategic plan has stated the following management goal for the Missouri River: Restore, protect, and maintain the diversity of historic Missouri River habitats, resources, and ecosystem functions in order that present and future generations may enjoy consumptive and non-consumptive outdoor recreational opportunities (NGPC 1996). To accomplish this goal the Nebraska Game and Parks Commission identified the following five objectives: • To restore terrestrial and aquatic floodplain habitat types by 2008. This would include old oxbows, chutes, side channels, sand bars, backwaters, wetlands, and other shallow water habitats. To restore ftows that reflect the natural hydrograph of the Missouri River by the year 2008. • To inform and educate the general public and constituency about Missouri River ecosystem functions and management. To double the number of total recreational use days by the year 2008. To investigate and manage native fish, wildlife, waterfowl, and fur bearers on a sustainable basis. Even though several of these objectives fall outside of NGPC management authority, this project has and will provide the data necessary to plan, implement and evaluate them. This strategic plan is currently being reviewed and updated.
Creel surveys on large rivers with numerous public and private access points are difficult and expensive to design and conduct. The first creel survey conducted on the channelized Missouri River in Nebraska was a roving creel during 1972 t01973 (Groen 1973). Segments of the channelized river covered included, Sioux City to Blair, Blair to Nebraska City and Nebraska City to Rulo. These same segments were surveyed again in 1978 and 1979 (Hesse 1980). The Missouri Department of Conservation conducted a recreational use survey on the channelized Missouri River from the mouth to the Iowa-Missouri state line in four segments over a four year period from 1983 through 1987 (Fleener 1989). The segment adjacent to Nebraska was sampled in 1985 and 1986 and extended from the lowaMissouri state line downstream to St Joseph, Missouri. The present project examining several reaches of the channelized Missouri River had several objectives: Develop a creel survey design that when repeated over time would measure changes in recreational fishing activity and success and allow us to estimate the effects of large scale restoration efforts on recreational fishing. Estimate recreational fishing use. Estimate the number and species of fish harvested and released by recreational anglers. Estimate recreational fishing effort on public and private lands and by boating anglers using public and private boat ramps Correlate fishing effort and success with a combination of season, physical habitat variables (location, macrohabitat, microhabitat, water temperature and secchi disk transparency) and fishing methods (bait) Develop recreational fishing educational information based on survey result
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