New dates and palaeoenvironmental evidence for the Middle to Upper Palaeolithic occupation of Higueral de Valleja Cave,southern Spain

A research programme has been set up at Higueral de Valleja Cave in southern Spain to investigate the late survival and eventual extinction of the southern Iberian Neanderthals and the arrival of modern humans. Of key interest in the first phase of research was to understand the depositional environment in the entrance chamber of the cave and to establish whether palaeoenvironmental and dating samples could be retrieved from the Middle and Upper Palaeolithic sequences. The outcome is a series of OSL, TL and radiocarbon dates showing that the cave was occupied by Neanderthal populations in Marine Isotope Stage (MIS) 3, if not earlier, and by modern human Solutrean populations during the last glacial maximum. Cave sediments provisionally indicate that the lower Middle Palaeolithic sequence (X–VIII) formed in warm and humid environments and the upper sequence (VIII–V) formed when the climate was cooler and drier. The presence of long grass phytoliths and of the small mammals Microtus duodecimcostatus, Microtus brecciensis and Apodemus sylvaticus in the upper sequence indicates that a range of habitat types persisted near the cave including grassland, scrubby vegetation, patchy tree cover and ponds. This raises the possibility that environmental factors were key factors in the late survival of Neanderthal populations at the cave.     

Staying cool in a changing climate: Reaching vulnerable populations during heat events

The frequency and intensity of hot weather events are expected to increase globally, threatening human health, especially among the elderly, poor, and chronically ill. Current literature indicates that emergency preparedness plans, heat health warning systems, and related interventions may not be reaching or supporting behavior change among those most vulnerable in heat events. Using a qualitative multiple case study design, we comprehensively examined practices of these populations to stay cool during hot weather (“cooling behaviors”) in four U.S. cities with documented racial/ethnic and socio-economic disparities and diverse heat preparedness strategies: Phoenix, Arizona; Detroit, Michigan; New York City, New York; and Philadelphia, Pennsylvania. Based on semi-structured in-depth interviews we conducted with 173 community members and organizational leaders during 2009–2010, we assessed why vulnerable populations do or do not participate in health-promoting behaviors at home or in their community during heat events, inquiring about perceptions of heat-related threats and vulnerability and the role of social support. While vulnerable populations often recognize heat's potential health threats, many overlook or disassociate from risk factors or rely on experiences living in or visiting warmer climates as a protective factor. Many adopt basic cooling behaviors, but unknowingly harmful behaviors such as improper use of fans and heating and cooling systems are also adopted. Decision-making related to commonly promoted behaviors such as air conditioner use and cooling center attendance is complex, and these resources are often inaccessible financially, physically, or culturally. Interviewees expressed how interpersonal, intergenerational relationships are generally but not always protective, where peer relationships are a valuable mechanism for facilitating cooling behaviors among the elderly during heat events. To prevent disparities in heat morbidity and mortality in an increasingly changing climate, we note the implications of local context, and we broadly inform heat preparedness plans, interventions, and messages by sharing the perspectives and words of community members representing vulnerable populations and leaders who work most closely with them.     

Re-thinking colonialism to prepare for the impacts of rapid environmental change

This essay demonstrates how key concepts from ecology can be applied within historical analyses in order to gain insights regarding contemporary environmental change. We employ a coupled human and natural systems conceptual framework in a nascent historical analysis of rapid societal and environmental change in colonial New England, where European colonization led to stark and rapid transformations. Introduced diseases reduced indigenous communities to a fraction of their pre-contact levels. European agriculture and associated pest species, deforestation and overharvest of ecologically influential species were among key aspects of the rapid changes in colonial New England. Cross-continental biotic introductions initiated reinforcing feedback loops that accelerated the transition of human and natural systems into novel states. Integrating colonial history and ecology can help identify important interactions between human and natural systems useful for contemporary societies adjusting to environmental change.     

Ultraviolet spectroscopy of Comet 9P/Tempel 1 with Alice/Rosetta during the Deep Impact encounter

We report on spectroscopic observations of periodic Comet 9P/Tempel 1 by the Alice ultraviolet spectrograph on the Rosetta spacecraft in conjunction with NASA's Deep Impact mission. Our objectives were to measure an increase in atomic and molecular emissions produced by the excavation of volatile sub-surface material. We unambiguously detected atomic oxygen emission from the quiescent coma but no enhancement at the 10% (1-σ) level following the impact. We derive a quiescent H₂O production rate of 9×¹⁰²⁷ molecules s⁻¹ with an estimated uncertainty of ∼30%. Our upper limits to the volatiles produced by the impact are consistent with other estimates.     

The dipole anisotropy of the 2 Micron All-Sky Redshift Survey

We estimate the acceleration on the Local Group (LG) from the 2 Micron All-Sky Redshift Survey (2MRS). The sample used includes about 23 200 galaxies with extinction-corrected magnitudes brighter than   K _s= 11.25  and it allows us to calculate the flux-weighted dipole. The near-infrared flux-weighted dipoles are very robust because they closely approximate a mass-weighted dipole, bypassing the effects of redshift distortions and require no preferred reference frame. This is combined with the redshift information to determine the change in dipole with distance. The misalignment angle between the LG and the cosmic microwave background (CMB) dipole drops to  12°± 7°  at around  50  h ⁻¹ Mpc  , but then increases at larger distances, reaching  21°± 8°  at around  130  h ⁻¹ Mpc  . Exclusion of the galaxies Maffei 1, Maffei 2, Dwingeloo 1, IC342 and M87 brings the resultant flux dipole to  14°± 7°  away from the CMB velocity dipole. In both cases, the dipole seemingly converges by  60  h ⁻¹ Mpc  . Assuming convergence, the comparison of the 2MRS flux dipole and the CMB dipole provides a value for the combination of the mass density and luminosity bias parameters  Ω^0.6_m/ b _L= 0.40 ± 0.09  .     

Compressibility of molten Apollo 17 orange glass and implications for density crossovers in the lunar mantle

We performed density measurements on a synthetic equivalent of lunar Apollo 17 74,220 “orange glass”, containing 9.1 wt% TiO₂, at superliquidus conditions in the pressure range 0.5-8.5 GPa and temperature range 1723-2223 K using the sink/float technique. In the lunar pressure range, two experiments containing pure forsterite (Fo₁₀₀) spheres at 1.0 GPa and 1727 K, and at 1.3 GPa-1739 K, showed neutral buoyancies, indicating that the density of molten orange glass was equal to the density of Fo₁₀₀ at these conditions (3.09 ± 0.02 g cm⁻³). A third tight sink/float bracket using Fo₉₀ spheres corresponds to a melt density of 3.25 ± 0.02 g cm⁻³ at ∼2.8 GPa and ∼1838 K.Our data predict a density crossover for the molten orange glass composition with equilibrium orthopyroxene at ∼2.8 GPa, equivalent to a depth of ∼600 km in the lunar mantle, and a density of ∼3.25 g cm⁻³. This crossover depth is close to the orange glass multiple saturation point, representing its minimum formation depth, at the appropriate oxygen fugacity (2.8-2.9 GPa). A density crossover with equilibrium olivine is predicted to fall outside the lunar pressure range (>4.7 GPa), indicating that molten orange glass is always less dense than its equilibrium olivines in the Moon. Our data therefore suggest that that lunar liquids with orange glass composition are buoyant with respect to their source region at P < ∼2.8 GPa, enabling their initial rise to the surface without the need for additional external driving forces.Fitting the density data to a Birch-Murnaghan equation of state at 2173 K leads to an array of acceptable solutions ranging between 16.1 and 20.3 GPa for the isothermal bulk modulus K₂₁₇₃ and 3.6-8 for its pressure derivative K′, with best-fit values K₂₁₇₃ = 18.8 GPa and K′ = 4.4 when assuming a model 1 bar density value of 2.86 g cm⁻³. When assuming a slightly lower 1 bar density value of 2.84 g cm⁻³ we find a range for K₂₁₇₃ of 14.4-18.0 and K′ 3.7-8.7, with best-fit values of 17.2 GPa and 4.5, respectively.