Direct N-body Simulations of Rubble Pile Collisions

There is increasing evidence that many km-sized bodies in the Solar System are piles of rubble bound together by gravity. We present results from a project to map the parameter space of collisions between km-sized spherical rubble piles. The results will assist in parameterization of collision outcomes for Solar System formation models and give insight into fragmentation scaling laws. We use a direct numerical method to evolve the positions and velocities of the rubble pile particles under the constraints of gravity and physical collisions. We test the dependence of the collision outcomes on impact parameter and speed, impactor spin, mass ratio, and coefficient of restitution. Speeds are kept low (< 10 m/s, appropriate for dynamically cool systems such as the primordial disk during early planet formation) so that the maximum strain on the component material does not exceed the crushing strength. We compare our results with analytic estimates and hydrocode simulations. Off-axis collisions can result in fast-spinning elongated remnants or contact binaries while fast collisions result in smaller fragments overall. Clumping of debris escaping from the remnant can occur, leading to the formation of smaller rubble piles. In the cases we tested, less than 2% of the system mass ends up orbiting the remnant. Initial spin can reduce or enhance collision outcomes, depending on the relative orientation of the spin and orbital angular momenta. We derive a relationship between impact speed and angle for critical dispersal of mass in the system. We find that our rubble piles are relatively easy to disperse, even at low impact speed, suggesting that greater dissipation is required if rubble piles are the true progenitors of protoplanets.Comment: 30 pages including 4 tables, 8 figures. Revised version to be published in Icarus

Asteroids Observed by The Sloan Digital Sky Survey

We announce the first public release of the SDSS Moving Object Catalog, with SDSS observations for 58,117 asteroids. The catalog lists astrometric and photometric data for moving objects observed prior to Dec 15, 2001, and also includes orbital elements for 10,592 previously known objects. We analyze the correlation between the orbital parameters and optical colors for the known objects, and confirm that asteroid dynamical families, defined as clusters in orbital parameter space, also strongly segregate in color space. Their distinctive optical colors indicate that the variations in chemical composition within a family are much smaller than the compositional differences between families, and strongly support earlier suggestions that asteroids belonging to a particular family have a common origin.Comment: 6 pages, 1 color figure, to be presented at "Astronomical Telescopes & Instrumentation", SPIE 200

Quantum-Liouville and Langevin Equations for Gravitational Radiation Damping

From a forward--backward path integral, we derive a master equation for the emission and absorption of gravitons by a massive quantum object in a heat bath of gravitons. Such an equation could describe collapse phenomena of dense stars. We also present a useful approximate Langevin equation for such a system.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper (including all PS fonts) at http://www.physik.fu-berlin.de/~kleinert/31

Do ESG Funds Deliver on Their Promises?

Corporations have received growing criticism for contributing to climate change, perpetuating racial and gender inequality, and failing to address other pressing social issues. In response to these concerns, shareholders are increasingly focusing on environmental, social, and corporate governance (ESG) criteria in selecting investments, and asset managers are responding by offering a growing number of ESG mutual funds. The flow of assets into ESG is one of the most dramatic trends in asset management. But are these funds giving investors what they promise? This question has attracted the attention of regulators, with the Department of Labor and the Securities and Exchange Commission (SEC) both taking steps to rein in ESG funds. The change in administration has created an opportunity to rethink these steps, but the rapid growth and evolution of the market mean regulators are acting without a clear picture of ESG investing. We fill this gap by offering the most complete empirical overview of ESG mutual funds to date. Combining comprehensive data on mutual funds with proprietary data from the several of the most significant ESG ratings firms, we provide a unique picture of the current ESG environment with an eye to informing regulatory policy. We evaluate a number of criticisms of ESG funds made by academics and policymakers and find them lacking. We find that ESG funds offer their investors increased ESG exposure. They also vote their shares differently from non-ESG funds and are more supportive of ESG principles. Our analysis shows that they do so without increasing costs or reducing returns. We conclude that ESG funds generally offer investors a differentiated and competitive investment product that is consistent with their labeling. In short, we see no reason to single out ESG funds for special regulation

High school subject selection in depression related cognitive tests

Aim: To investigate the effect of high school subject selection on cognitive tests relevant to young adults with depression. It was hypothesised that young adults (17-35) who studied advanced 76 mathematics rather than ordinary mathematics would perform significantly better on cognitive tests associated with problem solving such as Card Sort (perseverative errors) and Tower of London. Design: Cross-sectional design with purposive sampling. Purposive sampling was used to target young adults who had experienced depressive symptoms. Method: Thirty seven young adults (M=20.05 years, SD=2.97; 28 female, 9 male) studied advanced mathematics and 78 young adults (M=20.19 years, SD=3.61; 57 female, 21 male) studied ordinary mathematics. Participants were classified as either the "advanced mathematics" group: scored at least one high achievement (B grade) with no fails in advanced mathematics A, advanced mathematics B, physics, or chemistry; or the "ordinary mathematics" group who studied ordinary mathematics in their senior year at high school. Participants completed a battery of cognitive tests and semi structured interviews to determine depression severity and disorder classification. Results: Advanced mathematics group had significantly less: perseverative errors (p=.009), participants with depression (p=.004), depression severity (p=.002), anxiety severity (p=.015), number of depressive episodes (p=.035), and intelligence measure (p=.027) than the ordinary mathematics group. Other cognitive tests where the advanced group performed significantly better than the ordinary mathematics group included word recall trial 1 (p=.001), trial 2 (p=.036), and trial 3 (p=.023). A logistic regression with bootstrapping was run and demonstrated that perseverative errors (p=.016) as well as word recall trial 1 (p=.001) were still significant predictors of mathematics group when covaried with an intelligence measure, depression and anxiety variables. Conclusion: Young adults who studied advanced mathematics had significantly fewer perseverative errors than young adults who studied ordinary mathematics even when controlling for differences in depression. School subject selection should be included in depression studies to better evaluate whether it is a mediating factor for perseverative errors which are considered a possible trait cognitive deficit for depression

Role of social cognition for young adults with recurrent depression

Aim: To investigate the results of social cognition tests on young adults with either recurrent or nonrecurrent depression. This study tested three hypotheses: (1) young adults with recurrent depressive episodes (>2 episodes) would perform significantly poorer on social cognition tasks than nonrecurrent depression (1 or 2 episodes only); (2) deficits in negatively balanced prosody would be associated with deficits in other cognitive tasks due to the requirement of extra cognitive resources; and (3) anxiety severity not depression severity would be a predictor of recurrent depression. Design: Cross-sectional design with purposive sampling. Purposive sampling was used to target young adults who had experienced a depressive episode. Method: Eighty-four young adults (M=21.69 years, SD=4.14; 61 females, 23 males) with recurrent depression (>2 major depressive episodes) and 36 young adults (M=20.03 years, SD=3.23; 29 females, 7 males) with non-recurrent depression (1 or 2 major depressive episodes only) completed a cognitive battery and semi structured interviews including a clinical interview. Results: The recurrent depression group performed significantly poorer than the non-recurrent group in prosody matching (p=.015), but not in facial affect (p=.365). By grouping individual prosodymatching items into happy, surprise, afraid, sad, angry, neutral, and sarcasm items it was found that the recurrent group performed significantly poorer than the non-recurrent group in sarcasm items (p=.004) only. As prosody matching did not correlate with depression severity (p=.292) or anxiety severity (p=.345), prosody may be a trait deficit. Using linear regression with bootstrapping negatively balanced prosody (sad, angry, surprised) was significantly predicted by the Nback (1) task (p=.005). A logistic regression model with bootstrapping was run to determine if sarcasm items would still be independently associated with recurrent depression when co-varied with age, depression severity, and anxiety severity. Age (p=.009) and sarcasm items (p=.035) were both independently associated while depression severity (p=.824) and anxiety severity (p=.100) were not. Therefore both anxiety and depression severity were not predictors of the recurrent depression group. Omitting "Age" from the logistic regression the significance of sarcasm items increased to p=.004. Conclusion: Prosody matching (sarcasm items) a possible trait deficit may play a role in differentiating recurrent and non-recurrent depression

Do ESG Mutual Funds Deliver on Their Promises?

Corporations have received growing criticism for their role in climate change, perpetuating racial and gender inequality, and other pressing social issues. In response to these concerns, shareholders are increasingly focusing on environmental, social, and corporate governance (ESG) criteria in selecting investments, and asset managers are responding by offering a growing number of ESG mutual funds. The flow of assets into ESG is one of the most dramatic trends in asset management. But are these funds giving investors what they promise? This question has attracted the attention of regulators, with the Department of Labor and the Securities and Exchange Commission (SEC) both taking steps to rein in ESG funds. The change in administration has created an opportunity to rethink these steps, but the rapid growth and evolution of the market means regulators are acting without a clear picture of ESG investing. We step into this gap by offering the most complete empirical overview of ESG mutual funds to date. Combining comprehensive data on mutual funds with proprietary data from the several of the most significant ESG ratings firms, we provide a unique picture of the current ESG environment with an eye to informing regulatory policy. We evaluate a number of criticisms of ESG funds made by academics and policymakers and find them lacking. We find that ESG funds offer their investors increased ESG exposure. They also vote their shares differently from non-ESG funds and are more supportive of ESG principles. Our analysis shows that they do so without increasing costs or reducing returns. We conclude that ESG funds generally offer investors a differentiated and competitive investment product that is consistent with their labeling. In short, we see no reason to single out ESG funds for special regulation

High school subject selection in depression related cognitive tests

Aim: To investigate the effect of high school subject selection on cognitive tests relevant to young adults with depression. It was hypothesised that young adults (17-35) who studied advanced 76 mathematics rather than ordinary mathematics would perform significantly better on cognitive tests associated with problem solving such as Card Sort (perseverative errors) and Tower of London. Design: Cross-sectional design with purposive sampling. Purposive sampling was used to target young adults who had experienced depressive symptoms. Method: Thirty seven young adults (M=20.05 years, SD=2.97; 28 female, 9 male) studied advanced mathematics and 78 young adults (M=20.19 years, SD=3.61; 57 female, 21 male) studied ordinary mathematics. Participants were classified as either the "advanced mathematics" group: scored at least one high achievement (B grade) with no fails in advanced mathematics A, advanced mathematics B, physics, or chemistry; or the "ordinary mathematics" group who studied ordinary mathematics in their senior year at high school. Participants completed a battery of cognitive tests and semi structured interviews to determine depression severity and disorder classification. Results: Advanced mathematics group had significantly less: perseverative errors (p=.009), participants with depression (p=.004), depression severity (p=.002), anxiety severity (p=.015), number of depressive episodes (p=.035), and intelligence measure (p=.027) than the ordinary mathematics group. Other cognitive tests where the advanced group performed significantly better than the ordinary mathematics group included word recall trial 1 (p=.001), trial 2 (p=.036), and trial 3 (p=.023). A logistic regression with bootstrapping was run and demonstrated that perseverative errors (p=.016) as well as word recall trial 1 (p=.001) were still significant predictors of mathematics group when covaried with an intelligence measure, depression and anxiety variables. Conclusion: Young adults who studied advanced mathematics had significantly fewer perseverative errors than young adults who studied ordinary mathematics even when controlling for differences in depression. School subject selection should be included in depression studies to better evaluate whether it is a mediating factor for perseverative errors which are considered a possible trait cognitive deficit for depression

Care staff and family member perspectives on quality of life in people with very severe dementia in long-term care: a cross-sectional study.

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Little is known about the quality of life of people with very severe dementia in long-term care settings, and more information is needed about the properties of quality of life measures aimed at this group. In this study we explored the profiles of quality of life generated through proxy ratings by care staff and family members using the Quality of Life in Late-stage Dementia (QUALID) scale, examined factors associated with these ratings, and further investigated the psychometric properties of the QUALID. METHODS: Proxy ratings of quality of life using the QUALID were obtained for 105 residents with very severe dementia, categorised as meeting criteria for Functional Assessment Staging (FAST) stages 6 or 7, from members of care staff (n = 105) and family members (n = 73). A range of resident and staff factors were also assessed. RESULTS: Care staff and family member ratings were similar but were associated with different factors. Care staff ratings were significantly predicted by resident mood and awareness/responsiveness. Family member ratings were significantly predicted by use of antipsychotic medication. Factor analysis of QUALID scores suggested a two-factor solution for both care staff ratings and family member ratings. CONCLUSIONS: The findings offer novel evidence about predictors of care staff proxy ratings of quality of life and demonstrate that commonly-assessed resident variables explain little of the variability in family members' proxy ratings. The findings provide further information about the psychometric properties of the QUALID, and support the applicability of the QUALID as a means of examining quality of life in very severe dementia.LC: Higher Education Funding Council for Wales. CQ: National Institute for Social Care and Health Research and Economic & Social Research Council/ National Institute for Health Research. ZH: National Institute for Social Care and Health Research. RW: National Institute for Social Care and Health Research. RTW: Higher Education Funding Council for Wale