1,010 research outputs found
Adverse Selection in Private Annuity Markets and the Role of Mandatory Social Annuitization
We study the effects on the macroeconomic equilibrium, the wealth distribution, and welfare of adverse selection in private annuity markets in a closed economy inhabited by overlapping generations of heterogeneous agents who are distinguished by their health status. If an agent's health type is private information there will be a pooling equilibrium in the private annuity market. We also study the implications for the macro-economy and welfare of a social security system with mandatory contributions that are constant across health types. These social annuities are immune to adverse selection and therefore offer a higher rate of return than private annuities do. However, they have a negative effect on the steady-state capital intensity and welfare. The positive effect of a fair pooled rate of return on a fixed part of savings and a higher return on capital in equilibrium is outweighed by the negative consequences of increased adverse selection in the private annuity market and a lower wage rate
Assessing the threat of toxic contaminants to early marine survival of Chinook salmon in the Salish Sea
Human development of the Salish Sea has resulted in loss and modification of salmonid habitats, including reduced habitat quality due to contaminant inputs, particularly in the lower reaches of rivers and estuaries of the central Puget Sound. Chemical contaminants released into the Salish Sea from anthropogenic sources can reduce the health and productivity of salmon. Juvenile salmon are exposed to contaminants in freshwater, estuarine, and marine habitats but they are particularly vulnernable as they transition from fresh to saltwater because this life history stage is especially sensitive to stressors that may reduce their early marine survival. Reduced growth and disease resistance have been demonstrated for juvenile Chinook salmon exposed to environmentally relevant contaminant levels; however, synoptic, Puget Sound-wide surveys to assess the extent and magnitude of contaminant exposure are lacking. In this study we measured exposure of juvenile Chinook salmon to chemicals of concern that enter Puget Sound via stormwater, wastewater treatment facilities, atmospheric deposition to marine waters, and groundwater. During the spring and summer of 2013, outmigrating fish were sampled from the river mouthes and two adjacent marine shorelines at each of five Puget Sound river-estuary systems: Skagit, Snohomish, Green/Duwamish, Puyallup/Hylebos, and Nisqually. We (1) report the extent and magnitude of exposure, (2) compare exposure in outmigrants across five major river-estuary systems, and (3) evaluate potential effects on marine survival. Results will be used to establish a time series of contaminant conditions in juvenile Chinook salmon to measure the effectiveness of current toxics reductions strategies and actions, inform future pollution reduction efforts, and enhanced recovery of Chinook salmon
Celebrating 40 Years of the Midwest Nursing Research Society
The Midwest Nursing Research Society (MNRS) recently held its 40th annual conference and celebrated four decades of nursing research in the Midwest. MNRS continues to be one of the largest nursing research societies in the United States. Over the years, a vast majority of programmatic initiatives included education and tangible support for novice and experienced nurse researchers. In this article, the background for development of MNRS is reviewed with examination of driving forces that led to its creation. Three past presidents, Dr. Joyce Fitzpatrick, the first President of MNRS (1980- 1981); Dr. Nancy Bergstrom, the eighth President (1993-1995); and Dr. Sally Lusk, the 14th President (2005-2007), discuss challenges, opportunities, and the exceptional progress made toward fostering excellence in nursing research for the Midwest and contributing to nursing science on a national and global scale. Lessons from the past as well as opportunities for the future are addressed
COVID-19 pandemic quarantines and mental health among adolescents in Norway
Importance: Adolescence is a critical developmental phase when mental health disorders, such as anxiety and depression, often emerge. Stringent public health measures and quarantine mandates during the COVID-19 pandemic could threaten adolescent mental health. Objective: To investigate the associations of public health measures and quarantine experiences with mental distress among Norwegian adolescents and to explore if certain vulnerability factors moderate these associations. Design, Setting, and Participants: This longitudinal cohort study used repeated measures to capture variations in mental distress explained by the stringency of public health measures and quarantine experiences. Data from the Norwegian Mother, Father, and Child cohort study were linked to national health registries and a national stringency index from April 1, 2020, to February 17, 2021. Participant included 7787 Norwegian adolescents aged 16 to 18 years. Data were analyzed from October 2022 to October 2023. Exposures: Stringency index of public health measures and quarantine experiences including recent quarantine (within the last 2 weeks) and quarantine frequency (cumulative number of quarantine episodes). Main Outcome and Measures: Mental distress was measured using the Hopkins Symptom Checklist across 6 data collection waves. Results: In this study, 7787 participants were included in the analysis (4473 female [57%]; mean [SD] age, 17.0 [0.6] years). Stringent public health measures (β = 0.18; SE, 0.02; P < .001), recent quarantine (β = 0.11; SE, 0.02; P < .001), and frequent quarantine (β = 0.08; SE, 0.01; P < .001) were associated with higher levels of mental distress. The associations between public health measures and mental distress were not moderated by sex, age, prepandemic anxiety or depression, or genetic liability for mental health conditions. Frequency of quarantine appeared to be more strongly associated with mental distress among younger adolescents (β = -0.04; SE, 0.01; P = .008), those with parents with lower education (β = -0.04; SE, 0.01; P = .007), and those with lower genetic risk for depression (β = -0.03; SE, 0.01; P = .006). Conclusions and Relevance: In this study, younger adolescents, those with parents with lower education, or those with low genetic liability for depression appeared more vulnerable when being quarantined several times. These findings emphasize the need for targeted support strategies to better protect adolescent well-being during future crises. Adolescents who experienced increased mental distress during the COVID-19 pandemic may be at risk of continued mental health problems and in need of ongoing support
Statistics of Physical Properties of Dark Matter Clusters
We have identified over 2000 well resolved cluster halos, and also their
associated bound subhalos, from the output of a 1024^3 particle cosmological
N-body simulation (of box size 320 h^-1 Mpc and softening length 3.2 h^-1 kpc).
This has allowed us to measure halo quantities in a statistically meaningful
way, and for the first time analyse their distribution for a large and well
resolved sample. We characterize each halo in terms of its morphology,
concentration, spin, circular velocity and the fraction of their mass in
substructure. We also identify those halos that have not yet reached a state of
dynamical equilibrium using the virial theorem with an additional correction to
account for the surface pressure at the boundary. These amount to 3.4% of our
initial sample. For the virialized halos, we find a median of 5.6% of halo mass
is contained within substructure, with the distribution ranging between no
identified subhalos to 65%. The fraction of mass in substructure increases with
halo mass with logarithmic slope of 0.44 +- 0.06. Halos tend to have a prolate
morphology, becoming more so with increasing mass. Subhalos have a greater
orbital angular momentum per unit mass than their host halo. Furthermore, their
orbital angular momentum is typically well aligned with that of their host.
Overall, we find that dimensionless properties of dark matter halos do depend
on their mass, thereby demonstrating a lack of self-similarity.Comment: Updated to match version published in ApJ, includes longer discussion
of the virialisation criterium, 4 figures from original version deemed not
essential to the main results and conclusions removed, uses emulate ap
Grey and white matter correlates of recent and remote autobiographical memory retrieval:Insights from the dementias
The capacity to remember self-referential past events relies on the integrity of a distributed neural network. Controversy exists, however, regarding the involvement of specific brain structures for the retrieval of recently experienced versus more distant events. Here, we explored how characteristic patterns of atrophy in neurodegenerative disorders differentially disrupt remote versus recent autobiographical memory. Eleven behavioural-variant frontotemporal dementia, 10 semantic dementia, 15 Alzheimer's disease patients and 14 healthy older Controls completed the Autobiographical Interview. All patient groups displayed significant remote memory impairments relative to Controls. Similarly, recent period retrieval was significantly compromised in behavioural-variant frontotemporal dementia and Alzheimer's disease, yet semantic dementia patients scored in line with Controls. Voxel-based morphometry and diffusion tensor imaging analyses, for all participants combined, were conducted to investigate grey and white matter correlates of remote and recent autobiographical memory retrieval. Neural correlates common to both recent and remote time periods were identified, including the hippocampus, medial prefrontal, and frontopolar cortices, and the forceps minor and left hippocampal portion of the cingulum bundle. Regions exclusively implicated in each time period were also identified. The integrity of the anterior temporal cortices was related to the retrieval of remote memories, whereas the posterior cingulate cortex emerged as a structure significantly associated with recent autobiographical memory retrieval. This study represents the first investigation of the grey and white matter correlates of remote and recent autobiographical memory retrieval in neurodegenerative disorders. Our findings demonstrate the importance of core brain structures, including the medial prefrontal cortex and hippocampus, irrespective of time period, and point towards the contribution of discrete regions in mediating successful retrieval of distant versus recently experienced events
From the cell membrane to the nucleus: unearthing transport mechanisms for Dynein
Mutations in the motor protein cytoplasmic dynein have been found to cause Charcot-Marie-Tooth disease, spinal muscular atrophy, and severe intellectual disabilities in humans. In mouse models, neurodegeneration is observed. We sought to develop a novel model which could incorporate the effects of mutations on distance travelled and velocity. A mechanical model for the dynein mediated transport of endosomes is derived from first principles and solved numerically. The effects of variations in model parameter values are analysed to find those that have a significant impact on velocity and distance travelled. The model successfully describes the processivity of dynein and matches qualitatively the velocity profiles observed in experiments
Effects of polycyclic aromatic hydrocarbons (PAHs) on Pacific herring (Clupea pallasii) embryos exposed to creosote-treated pilings related to a piling removal project in Quilcene Bay, Washington
Fish embryos spawned in Puget Sound nearshore marine habitats face a risk of exposure to a wide variety of toxic chemical pollutants during their incubation. Of particular concern are polycyclic aromatic hydrocarbons (PAHs), chemicals originating from oil spills, combusted fossil fuels, and creosote-treated pilings (CTPs). Removal of CTPs and prohibiting their use in marine waters are two recovery practices aimed at reducing PAHs and other creosote-related chemicals in marine waters. We used manually spawned and field-deployed Pacific herring embryos as a sensitive indicator of PAH exposure from CTPs, to test the efficacy of a CTP removal project in Quilcene Bay Washington. Embryos were deployed near CTPs in a 100-year-old derelict CTP field (1) before the CTPs were removed, (2) just after the removal process, to evaluate whether PAHs were released during removal, and (3) one year later, to evaluate whether PAHs lingered after CTP removal. Embryos incubated in the undisturbed CTP field prior to CTP removal exhibited PAH body burdens approximately five times higher than at reference areas, though total PAHs in the CTP-field embryos were below health effects thresholds. The CTP removal project was not fully completed during this study; CTP debris remained in the piling field and many CTPs were cut at the seafloor, resulting in freshly exposed CTP surfaces after the removal project ended. PAH concentrations in embryos sampled during and after CTP removal were 25x to 83x higher than reference embryos, and many exceeded health effects thresholds. PAH concentrations in embryos after CTP removal correlated with distance from former CTP locations. In addition, expression of cyp1a, a gene involved in PAH-detoxification, was correlated with PAH body burden. These results link embryo health with toxic contaminants associated with CTPs and illustrate the importance of fastidious adherence to appropriate CTP removal protocols to avoid contaminant risks to biota
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