Stony Brook University

About: Stony Brook University is a education organization based out in Stony Brook, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32534 authors who have published 68218 publications receiving 3035131 citations. The organization is also known as: State University of New York at Stony Brook & SUNY Stony Brook.

Age differences in major depression: results from the National Comorbidity Survey Replication (NCS-R)

Abstract: Community surveys consistently find that elderly people have much less clinical depression than younger people (Blazer & Hybels, 2005; Jorm, 2000). A number of explanations have been proposed for this finding, most focusing on the possibility that depression is underestimated among the elderly. Suggested biases include age-related differentials in recall, mortality, selection out of the household population into nursing homes, willingness to participate in surveys, and willingness to admit psychiatric symptoms in interviews (Schoevers et al., 2008; Snowdon, 1997). However, evidence for these methodological interpretations is weak (Ernst & Angst, 1995), leading some commentators to conclude that the low estimated prevalence of depression among the elderly is genuine (Blazer & Hybels, 2005). One issue that complicates analysis of late-life depression is that many physical disorders become increasingly prevalent in old age, making boundaries with depression sometimes unclear and raising the possibility that depression is under-estimated because it is confused with the symptoms of physical disorders (Drayer et al., 2005). This issue is complicated by the fact that some somatic disorders that increase with age can induce depression (Bremmer et al., 2008; Salaycik et al., 2007) while late-life depression can increase risk of some physical disorders (Bremmer et al., 2007; Petronijevic et al., 2008). In an effort to shed light on the possible age-related under-estimation of depression in epidemiological studies due to confounding with physical disorders, we analyzed age-related changes in associations of physical disorders with DSM-IV major depressive episodes (MDE) in the National Comorbidity Survey Replication (NCS-R) (Kessler & Merikangas, 2004). Parallel analysis was carried out with comorbidity between MDE and other DSM-IV mental disorders to determine if the patterns for physical disorders are unique or the same as for mental disorders. MDE was defined without either organic exclusions or diagnostic hierarchy rules to facilitate investigation of comorbidity. Our primary aims were to see if the estimated prevalence of MDE declines with age and to evaluate the extent to which comorbidity of MDE with other disorders changes with age. In studying comorbidity, we focused on associations rather than conditional prevalence, as data on age-related changes in prevalence exist (Blazer et al., 1987; Kennedy et al., 1990) but not data on age-related changes in associations. An examination of these associations is of interest because we would expect them to increase with age if the assessment of MDE is confounded by physical disorders. As a preliminary to the analysis of comorbidity, we examined basic MDE prevalence by age to show that an inverse age-MDE relationship does, in fact, exist in the NCS-R. We then examined age differences in the ratios of recent (30-day and 12-month) to lifetime prevalence, expecting that recall bias would produce higher ratios among elderly than younger respondents whereas substantive patterns would produce the opposite pattern. We also investigated whether MDE age-of-onset distributions differ by age, expecting that recall bias would result in these distributions being skewed more to the right among older than younger respondents. We then compared age-related differences in median numbers of lifetime MDE episodes among respondents with a history of MDE, expecting that recall bias would result in these values not increasing with age in a substantively plausible way. We then examined age differences in the persistence and severity of 12-month MDE, which we assumed would be less influenced by recall bias than data on lifetime MDE. We are unaware of any previous attempt to investigate these specifications in the context of an analysis of comorbidity between MDE and other disorders.

Energy loss and flow of heavy quarks in Au+Au collisions at sNN=200GeV

Abstract: The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < p(T) < 9 GeV/c at midrapidity (y < 0.35) from heavy-flavor (charm and bottom) decays in Au + Au collisions at root s(NN) = 200 GeV. The nuclear modification factor R-AA relative to p + p collisions shows a strong suppression in central Au + Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC energies. A large azimuthal anisotropy v(2) with respect to the reaction plane is observed for 0.5 < p(T) < 5 GeV/c indicating substantial heavy-flavor elliptic flow. Both R-AA and v(2) show a p(T) dependence different from those of neutral pions. A comparison to transport models which simultaneously describe R-AA(p(T)) and v(2)(p(T)) suggests that the viscosity to entropy density ratio is close to the conjectured quantum lower bound, i.e., near a perfect fluid.

It's worse than you thought: The feedback negativity and violations of reward prediction in gambling tasks

Abstract: The reinforcement learning theory suggests that the feedback negativity should be larger when feedback is unexpected. Two recent studies found, however, that the feedback negativity was unaffected by outcome probability. To further examine this issue, participants in the present studies made reward predictions on each trial of a gambling task where objective reward probability was indicated by a cue. In Study 1, participants made reward predictions following the cue, but prior to their gambling choice; in Study 2, predictions were made following their gambling choice. Predicted and unpredicted outcomes were associated with equivalent feedback negativities in Study 1. In Study 2, however, the feedback negativity was larger for unpredicted outcomes. These data suggest that the magnitude of the feedback negativity is sensitive to violations of reward prediction, but that this effect may depend on the close coupling of prediction and outcome.

Outcome over seven years of healthy adults with and without subjective cognitive impairment.

Abstract: Background Subjective cognitive impairment (SCI) in older persons without manifest symptomatology is a common condition with a largely unclear prognosis. We hypothesized that (1) examining outcome for a sufficient period by using conversion to mild cognitive impairment (MCI) or dementia would clarify SCI prognosis, and (2) with the aforementioned procedures, the prognosis of SCI subjects would differ significantly from that of demographically matched healthy subjects, free of SCI, termed no cognitive impairment (NCI) subjects. Methods A consecutive series of healthy subjects, aged ≥40 years, presenting with NCI or SCI to a brain aging and dementia research center during a 14-year interval, were studied and followed up during an 18-year observation window. The study population (60 NCI, 200 SCI, 60% female) had a mean age of 67.2 ± 9.1 years, was well-educated (mean, 15.5 ± 2.7 years), and cognitively normal (Mini-Mental State Examination, 29.1 ± 1.2). Results A total of 213 subjects (81.9% of the study population) were followed up. Follow-up occurred during a mean period of 6.8 ± 3.4 years, and subjects had a mean of 2.9 ± 1.6 follow-up visits. Seven NCI (14.9%) and 90 SCI (54.2%) subjects declined ( P P = .0003). Conclusions These results indicate that SCI in subjects with normal cognition is a harbinger of further decline in most subjects during a 7-year mean follow-up interval. Relevance for community populations should be investigated, and prevention studies in this at-risk population should be explored.

A marine biogenic source of atmospheric ice-nucleating particles

Abstract: The amount of ice present in clouds can affect cloud lifetime, precipitation and radiative properties. The formation of ice in clouds is facilitated by the presence of airborne ice-nucleating particles. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice. Sea-spray aerosol contains large amounts of organic material that is ejected into the atmosphere during bubble bursting at the organically enriched sea-air interface or sea surface microlayer. Here we show that organic material in the sea surface microlayer nucleates ice under conditions relevant for mixed-phase cloud and high-altitude ice cloud formation. The ice-nucleating material is probably biogenic and less than approximately 0.2 micrometres in size. We find that exudates separated from cells of the marine diatom Thalassiosira pseudonana nucleate ice, and propose that organic material associated with phytoplankton cell exudates is a likely candidate for the observed ice-nucleating ability of the microlayer samples. Global model simulations of marine organic aerosol, in combination with our measurements, suggest that marine organic material may be an important source of ice-nucleating particles in remote marine environments such as the Southern Ocean, North Pacific Ocean and North Atlantic Ocean.