Middle Stone Age (MSA) site distributions in eastern Africa and their relationship to Quaternary environmental change, refugia and the evolution of Homo sapiens

This paper considers the evolution of Homo sapiens in eastern Africa in relation to refugia and bottlenecks around ~200 ka BP, at a macro scale. Middle Stone Age (MSA) lithics, site distributions and locations are analysed in relation to palaeovegetation maps of the last glacial/interglacial cycle, which are used as a proxy for earlier climate cycles. A ‘‘push and pull’’ model is then postulated for the spread of Homo sapiens out of refugia in eastern Africa, involving both volcanism (push) and habitat availability (pull). A date within OIS 5 is suggested for this expansion to other parts of the continent, and potentially further a?eld, contrary to a frequently proposed expansion within OIS 3. ©2008 Elsevier Ltd. All rights reserved.

Leisure sports and postural control:Can a black belt protect your balance from aging?

To determine potential benefits of intensive leisure sports for age-related changes in postural control, we tested 3 activity groups comprising 70 young (M = 21.67 years, SD = 2.80) and 73 older (M = 62.60 years, SD = 5.19) men. Activity groups were martial artists, who held at least 1st Dan (black belt), sportive individuals exercising sports without explicit balance components, and nonsportive controls. Martial artists had an advantage over sportive individuals in dynamic posture tasks (upright stance on a sway-referenced platform), and these 2 active groups showed better postural control than nonsportive participants. Age-related differences in postural control were larger in nonsportive men compared with the 2 active groups, who were similar in this respect. In contrast, negative age differences in other sensorimotor and cognitive functions did not differ between activity groups. We concluded that individuals engaging in intensive recreational sports have long-term advantages in postural control. However, even in older martial artists with years of practice in their sports, we observed considerable differences favoring the young. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

A pilot study of a family focused, psychosocial intervention with war-exposed youth at risk of attack and abduction in north-eastern Democratic Republic of Congo

Rural communities in the Haut-Uele Province of northern Democratic Republic of Congo live in constant danger of attack and/or abduction by units of the Lord's Resistance Army operating in the region. This pilot study sought to develop and evaluate a community-participative psychosocial intervention involving life skills and relaxation training and Mobile Cinema screenings with this war-affected population living under current threat. 159 war-affected children and young people (aged 7-18) from the villages of Kiliwa and Li-May in north-eastern DR Congo took part in this study. In total, 22% of participants had been abduction previously while 73% had a family member abducted. Symptoms of post-traumatic stress reactions, internalising problems, conduct problems and pro-social behaviour were assessed by blinded interviewers at pre- and post-intervention and at 3-month follow-up. Participants were randomised (with an accompanying caregiver) to 8 sessions of a group-based, community-participative, psychosocial intervention (n=79) carried out by supervised local, lay facilitators or a wait-list control group (n=80). Average seminar attendance rates were high: 88% for participants and 84% for caregivers. Drop-out was low: 97% of participants were assessed at post-intervention and 88% at 3 month follow-up. At post-test, participants reported significantly fewer symptoms of post-traumatic stress reactions compared to controls (Cohen's d=0.40). At 3 month follow up, large improvements in internalising symptoms and moderate improvements in pro-social scores were reported, with caregivers noting a moderate to large decline in conduct problems among the young people. Trial Registration clinicalTrials.gov, Identifier: NCT01542398.

Main-belt Comet P/2012 T1 (PANSTARRS)

We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 μm that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q CN <1.5 × 1023 mol s-1, from which we infer a water production rate of Q_H_2O100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the ~155 Myr old Lixiaohua asteroid family. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and made possible by the generous financial support of the W. M. Keck Foundation, the Magellan Telescopes located at Las Campanas Observatory, Chile, and the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Observational Constraints on the Catastrophic Disruption Rate of Small Main Belt Asteroids

We have calculated 90% confidence limits on the steady-state rate of catastrophic disruptions of main belt asteroids in terms of the absolute magnitude at which one catastrophic disruption occurs per year  as a function of the post-disruption increase in brightness (Δm) and subsequent brightness decay rate (τ  ). The confidence limits were calculated using the brightest unknown main belt asteroid (V=18.5) detected with the Pan-STARRS1 (Pan-STARRS1) telescope. We measured the Pan-STARRS1’s catastrophic disruption detection efficiency over a 453-day interval using the Pan-STARRS moving object processing system (MOPS) and a simple model for the catastrophic disruption event’s photometric behavior in a small aperture centered on the catastrophic disruption event. We then calculated the  contours in the ranges from  and  encompassing measured values from known cratering and disruption events and our model’s predictions. Our simplistic catastrophic disruption model suggests that  and  which would imply that H_0≳28—strongly inconsistent withH_{0,B2005=23.26±0.02} predicted by Bottke et al. (Bottke, W.F., Durda, D.D., Nesvorný, D., Jedicke, R., Morbidelli, A., Vokrouhlický, D., Levison, H.F. [2005]. Icarus, 179, 63–94.) using purely collisional models. However, if we assume that H_0=H0,B2005 our results constrain , inconsistent with our simplistic impact-generated catastrophic disruption model. We postulate that the solution to the discrepancy is that >99% of main belt catastrophic disruptions in the size range to which this study was sensitive (∼100 m) are not impact-generated, but are instead due to fainter rotational breakups, of which the recent discoveries of disrupted asteroids P/2013 P5 and P/2013 R3 are probable examples. We estimate that current and upcoming asteroid surveys may discover up to 10 catastrophic disruptions/year brighter than V=18.5.

Stable Isotope Dietary Analysis of Prehistoric Populations from the Minusinsk Basin, Southern Siberia, Russia: A new chronological framework for the introduction of millet to the eastern Eurasian steppe

We report the results of stable carbon and nitrogen isotope analysis of 354 human and faunal samples from five archaeological cultures of the Minusinsk Basin, Southern Siberia – Afanasyevo, Okunevo, Andronovo, Karasuk and Tagar (ca. 2700–1 BC) – a key location in Eurasia due to its position on a northern corridor linking China and central Eurasia. The results indicate that the diet of Eneolithic to Middle Bronze Age (Afanasyevo to Andronovo) populations was primarily C3-based, with C4 plants only becoming an important component of the diet in the Late Bronze Age Karasuk and Early Iron Age Tagar cultures. Freshwater fish seems to have been an important constituent of the diets in all groups. The findings constitute the earliest concrete evidence for the substantial use of millet in the eastern Eurasian steppe. We propose that it was probably introduced from Northwestern China during the Karasuk culture at the start of the Late Bronze Age, ca. 1500 BC. We conclude with a discussion of the implications for the nature of pastoralist economies on the steppes.

The main-belt comets: The Pan-STARRS1 perspective

We analyze a set of 760 475 observations of 333 026 unique main-belt objects obtained by the Pan-STARRS1(PS1) survey telescope between 2012 May 20 and 2013 November 9, a period during which PS1 discoveredtwo main-belt comets, P/2012 T1 (PANSTARRS) and P/2013 R3 (Catalina-PANSTARRS). PS1 cometdetection procedures currently consist of the comparison of the point spread functions (PSFs) of movingobjects to those of reference stars, and the flagging of objects that show anomalously large radial PSFwidths for human evaluation and possible observational follow-up. Based on the number of missed discoveryopportunities among comets discovered by other observers, we estimate an upper limit comet discoveryefficiency rate of 70% for PS1. Additional analyses that could improve comet discovery yields infuture surveys include linear PSF analysis, modeling of trailed stellar PSFs for comparison to trailed movingobject PSFs, searches for azimuthally localized activity, comparison of point-source-optimized photometryto extended-source-optimized photometry, searches for photometric excesses in objects withknown absolute magnitudes, and crowd-sourcing. Analysis of the discovery statistics of the PS1 surveyindicates an expected fraction of 59 MBCs per 106 outer main-belt asteroids (corresponding to a totalexpected population of 140 MBCs among the outer main-belt asteroid population with absolute magnitudesof 12 < HV < 19:5), and a 95% confidence upper limit of 96 MBCs per 106 outer main-belt asteroids(corresponding to a total of 230 MBCs), assuming a detection efficiency of 50%. We note howeverthat significantly more sensitive future surveys (particularly those utilizing larger aperture telescopes)could detect many more MBCs than estimated here. Examination of the orbital element distribution ofall known MBCs reveals an excess of high eccentricities (0:1 < e < 0:3) relative to the background asteroidpopulation. Theoretical calculations show that, given these eccentricities, the sublimation rate for atypical MBC is orders of magnitude larger at perihelion than at aphelion, providing a plausible physicalexplanation for the observed behavior of MBCs peaking in observed activity strength near perihelion.These results indicate that the overall rate of mantle growth should be slow, consistent with observationalevidence that MBC activity can be sustained over multiple orbit passages.

Sublimation-Driven Activity in Main-Belt Comet 313p/Gibbs

We present an observational and dynamical study of newly discovered main-belt comet 313P/Gibbs. We find that the object is clearly active both in observations obtained in 2014 and in precovery observations obtained in 2003 by the Sloan Digital Sky Survey, strongly suggestingthat its activity is sublimation-driven. This conclusion is supported by a photometric analysis showing an increase in the total brightness of the comet over the 2014 observing period, and dust modeling resultsshowing that the dust emission persists over at least three months during both active periods, where we find start dates for emission nolater than 2003 July 24 ± 10 for the 2003 active period and 2014 July 28 ± 10 for the 2014 active period. From serendipitous observations by the Subaru Telescope in 2004 when the object was apparently inactive, we estimate that the nucleus has an absolute R-band magnitude of HR = 17.1 ± 0.3, corresponding to aneffective nucleus radius of re ∼ 1.00 ± 0.15 km.The object’s faintness at that time means we cannot rule out the presence of activity, and so this computed radius should be consideredan upper limit. We find that 313P’s orbit is intrinsically chaotic, having a Lyapunov time of Tl = 12,000 yr and beinglocated near two three-body mean-motion resonances with Jupiter andSaturn, 11J-1S-5A and 10J+12S-7A, yet appears stable over >50 Myr in an apparent example of stable chaos. We furthermore find that 313P is the second main-belt comet, after P/2012 T1 (PANSTARRS), to belong tothe ∼155 Myr old Lixiaohua asteroid family.

Discovery of Main-Belt Comet P/2006 VW139 by Pan-STARRS1

We describe the discovery of comet-like activity in main-belt asteroid (300163) 2006 VW139 (later re-designated as Comet P/2006 VW139) by Pan-STARRS1. We also detail follow-up photometric, spectroscopic, and dynamical analyses of the object.