Photometry of Irregular Satellites of Uranus and Neptune

We present BVR photometric colors of six Uranian and two Neptunian irregular satellites, collected using the Magellan Observatory (Las Campanas, Chile) and the Keck Observatory, (Manua Kea, Hawaii). The colors range from neutral to light red, and like the Jovian and the Saturnian irregulars (Grav et al. 2003) there is an apparent lack of the extremely red objects found among the Centaurs and Kuiper belt objects. The Uranian irregulars can be divided into three possible dynamical families, but the colors collected show that two of these dynamical families, the Caliban and Sycorax-clusters, have heterogeneous colors. Of the third possible family, the 168-degree cluster containing two objects with similar average inclinations but quite different average semi-major axis, only one object (U XXI Trinculo) was observed. The heterogeneous colors and the large dispersion of the average orbital elements leads us to doubt that they are collisional families. We favor single captures as a more likely scenario. The two neptunians observed (N II Nereid and S/2002 N1) both have very similar neutral, sun-like colors. Together with the high collisional probability between these two objects over the age of the solar system (Nesvorny et al. 2003, Holman et al. 2004), this suggests that S/2002 N1 be a fragment of Nereid, broken loose during a collision or cratering event with an undetermined impactor.Comment: 13 pages (including 3 figures and 2 tables). Submitted to ApJ Letter

HEDGE FUND DUE DILIGENCE: A SOURCE OF ALPHA IN A HEDGE FUND PORTFOLIO STRATEGY

Due diligence is an important source of alpha in a well designed hedge fund portfolio strategy. It is generally understood that the high returns possible in investing in hedge funds are somewhat offset by the relative lack of transparency on operational issues. The performance of a diversified hedge fund portfolio can be enhanced by excluding those funds likely to do poorly – or fail – due to operational risk concerns. However, effective due diligence is an expensive concern. This implies that there is a strong competitive advantage to those funds of funds sufficiently large to absorb this fixed and necessary cost. The consequent economies of scale that we document in funds of funds are quite substantial and support the proposition that due diligence is a source of alpha in hedge fund investment

Diagnostic work-up of patients presenting in primary care with lower abdominal symptoms:which faecal test and triage strategy should be used?

Bowel endoscopy referrals from primary care have increased steadily over recent years. However, most patients do not have significant colorectal disease (SCD). Therefore, strategies to select those who would benefit most from endoscopy are of current interest. A recent study developed a multivariable diagnostic model for SCD with routine clinical information, extended with quantitative faecal calprotectin (f-C) point-of-care (POC) testing and/or qualitative POC faecal immunochemical test (FIT) for haemoglobin (f-Hb) results. This study used POC tests for both f-C and f-Hb; however, POC tests have many disadvantages and there are several reasons why quantitative measurements of f-Hb are advantageous. Quantitative faecal immunochemical tests have been used very successfully in triage of patients presenting in primary care as a rule-out test. Studies have compared f-C and f-Hb in this clinical context and consider that f-C is not required in diagnosis. A single quantitative f-Hb result, without any clinical information, could be sufficient to decide whom to refer for endoscopy and, because of the significant overlap of symptoms in those with and without SCD, could be the primary investigation performed. Please see related article: http://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-016-0684-5

Youth sport in the time of COVID-19: considerations for researchers and practitioners

COVID-19 represents an unprecedented challenge for the youth sport sector. Due to public health policies designed to slow down the transmission of this highly infectious disease and mitigate secondary impacts, youth sport programs around the world have experienced sudden interruptions to their activities. In this commentary, we put forward the Personal Assets Framework as a tool to explore the potential implications of COVID-19 on youth sport development. Adaptations to the dynamic elements of the sport experience, including personal engagement in activities (i.e. virtual coaching; developmental trajectories), quality social dynamics (i.e. athlete relationships; health and well-being), and appropriate settings and organizational structures (i.e. social-cultural factors; safety concerns), are explored. This article will also discuss the potential consequences of changes in these dynamic elements on immediate, short-, and long-term developmental outcomes. Finally, we offer contextual, methodological, and practical considerations for researchers and practitioners operating in youth sport to consider during this crisis

Mannose binding lectin is required for alphavirus-induced arthritis/myositis

Mosquito-borne alphaviruses such as chikungunya virus and Ross River virus (RRV) are emerging pathogens capable of causing large-scale epidemics of virus-induced arthritis and myositis. The pathology of RRV-induced disease in both humans and mice is associated with induction of the host inflammatory response within the muscle and joints, and prior studies have demonstrated that the host complement system contributes to development of disease. In this study, we have used a mouse model of RRV-induced disease to identify and characterize which complement activation pathways mediate disease progression after infection, and we have identified the mannose binding lectin (MBL) pathway, but not the classical or alternative complement activation pathways, as essential for development of RRV-induced disease. MBL deposition was enhanced in RRV infected muscle tissue from wild type mice and RRV infected MBL deficient mice exhibited reduced disease, tissue damage, and complement deposition compared to wild-type mice. In contrast, mice deficient for key components of the classical or alternative complement activation pathways still developed severe RRV-induced disease. Further characterization of MBL deficient mice demonstrated that similar to C3(-/-) mice, viral replication and inflammatory cell recruitment were equivalent to wild type animals, suggesting that RRV-mediated induction of complement dependent immune pathology is largely MBL dependent. Consistent with these findings, human patients diagnosed with RRV disease had elevated serum MBL levels compared to healthy controls, and MBL levels in the serum and synovial fluid correlated with severity of disease. These findings demonstrate a role for MBL in promoting RRV-induced disease in both mice and humans and suggest that the MBL pathway of complement activation may be an effective target for therapeutic intervention for humans suffering from RRV-induced arthritis and myositis.This work was supported by NIH/NIAMS R01 AR 047190 awarded to MTH