The Quaternary lions of Ukraine and a trend of decreasing size in Panthera spelaea (advance online)

The fossil record of the cave lion, Panthera spelaea, suggests a gradual decrease in body size, the process peaking just before the extinction of the species at the end of the Late Pleistocene. Such an evolutionary trend appears rather unusual for a large felid species and requires further investigation. This study reviews the cave lions of Ukraine, whose fossils are known from 46 localities dated from 800 kyr to 18–17 kyr ago, with a special emphasis on size changes through time. We describe several important finds including those of Panthera spelaea fossilis from Sambir, Panthera spelaea ssp. from Bilykh Stin Cave and Panthera spelaea spelaea from Kryshtaleva Cave. We make subspecific identifications of specimens from the region and focus on their size characteristics. Our analysis of Ukrainian cave lions agrees with the temporal trend of decreasing size, particularly accelerating during MIS 2, as exemplified by the extremely small female skull from Kryshtaleva Cave. We provide a direct AMS date for this specimen (22.0–21.5 cal kyr BP), which suggests that the Kryshtaleva lioness must have belonged to a Panthera spelaea spelaea population forced south by the spreading ice sheet. We discuss some palaeoecological aspects of the evolutionary history and eventual extinction of the cave lion. Finally, we review the subfossil records of the extant lion Panthera leo known from several Ukrainian sites archaeologically dated to 6.4–2.0 kyr BP. These finds most probably represent the Persian lion Panthera leo persica

The Quaternary lions of Ukraine and a trend of decreasing size in Panthera spelaea

The fossil record of the cave lion, Panthera spelaea, suggests a gradual decrease in body size, the process peaking just before the extinction of the species at the end of the Late Pleistocene. Such an evolutionary trend appears rather unusual for a large felid species and requires further investigation. This study reviews the cave lions of Ukraine, whose fossils are known from 46 localities dated from 800 kyr to 18–17 kyr ago, with a special emphasis on size changes through time. We describe several important finds including those of Panthera spelaea fossilis from Sambir, Panthera spelaea ssp. from Bilykh Stin Cave and Panthera spelaea spelaea from Kryshtaleva Cave. We make subspecific identifications of specimens from the region and focus on their size characteristics. Our analysis of Ukrainian cave lions agrees with the temporal trend of decreasing size, particularly accelerating during MIS 2, as exemplified by the extremely small female skull from Kryshtaleva Cave. We provide a direct AMS date for this specimen (22.0–21.5 cal kyr BP), which suggests that the Kryshtaleva lioness must have belonged to a Panthera spelaea spelaea population forced south by the spreading ice sheet. We discuss some palaeoecologi- cal aspects of the evolutionary history and eventual extinction of the cave lion. Finally, we review the subfossil records of the extant lion Panthera leo known from several Ukrainian sites archaeologically dated to 6.4–2.0 kyr BP. These finds most probably represent the Persian lion Panthera leo persica

Healthy ageing and home: The perspectives of very old people in five European countries

This paper reports on in-depth research, using a grounded theory approach, to examine the ways in which very old people perceive healthy ageing in the context of living alone at home within urban settings in five European countries. This qualitative study was part of a cross-national project entitled ENABLE-AGE which examined the relationship between home and healthy ageing. Interviews explored the notion of healthy ageing, the meaning and importance of home, conceptualisations of independence and autonomy and links between healthy ageing and home. Data analysis identified five ways in which older people constructed healthy ageing: home and keeping active; managing lifestyles, health and illness; balancing social life; and balancing material and financial circumstances. Older people reflected on their everyday lives at home in terms of being engaged in purposeful, meaningful action and evaluated healthy ageing in relation to the symbolic and practical affordances of the home, contextualised within constructions of their national context. The research suggests that older people perceive healthy ageing as an active achievement, created through individual, personal effort and supported through social ties despite the health, financial and social decline associated with growing older. The physicality and spatiality of home provided the context for establishing and evaluating the notion of healthy ageing, whilst the experienced relationship between home, life history and identity created a meaningful space within which healthy ageing was negotiated

A Comparison of Snow Depth on Sea Ice Retrievals Using Airborne Altimeters and an AMSR-E Simulator

A comparison of snow depths on sea ice was made using airborne altimeters and an Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) simulator. The data were collected during the March 2006 National Aeronautics and Space Administration (NASA) Arctic field campaign utilizing the NASA P-3B aircraft. The campaign consisted of an initial series of coordinated surface and aircraft measurements over Elson Lagoon, Alaska and adjacent seas followed by a series of large-scale (100 km ? 50 km) coordinated aircraft and AMSR-E snow depth measurements over portions of the Chukchi and Beaufort seas. This paper focuses on the latter part of the campaign. The P-3B aircraft carried the University of Colorado Polarimetric Scanning Radiometer (PSR-A), the NASA Wallops Airborne Topographic Mapper (ATM) lidar altimeter, and the University of Kansas Delay-Doppler (D2P) radar altimeter. The PSR-A was used as an AMSR-E simulator, whereas the ATM and D2P altimeters were used in combination to provide an independent estimate of snow depth. Results of a comparison between the altimeter-derived snow depths and the equivalent AMSR-E snow depths using PSR-A brightness temperatures calibrated relative to AMSR-E are presented. Data collected over a frozen coastal polynya were used to intercalibrate the ATM and D2P altimeters before estimating an altimeter snow depth. Results show that the mean difference between the PSR and altimeter snow depths is -2.4 cm (PSR minus altimeter) with a standard deviation of 7.7 cm. The RMS difference is 8.0 cm. The overall correlation between the two snow depth data sets is 0.59

The secret world of shrimps: polarisation vision at its best

Animal vision spans a great range of complexity, with systems evolving to detect variations in optical intensity, distribution, colour, and polarisation. Polarisation vision systems studied to date detect one to four channels of linear polarisation, combining them in opponent pairs to provide intensity-independent operation. Circular polarisation vision has never been seen, and is widely believed to play no part in animal vision. Polarisation is fully measured via Stokes' parameters--obtained by combined linear and circular polarisation measurements. Optimal polarisation vision is the ability to see Stokes' parameters: here we show that the crustacean \emph{Gonodactylus smithii} measures the exact components required. This vision provides optimal contrast-enhancement, and precise determination of polarisation with no confusion-states or neutral-points--significant advantages. We emphasise that linear and circular polarisation vision are not different modalities--both are necessary for optimal polarisation vision, regardless of the presence of strongly linear or circularly polarised features in the animal's environment.Comment: 10 pages, 6 figures, 2 table

Geocronologia com 210Pb na avaliação das taxas de sedimentação e da dinâmica deposicional na Lagoa Itapeva, sul do Brasil

As a result of anthropogenic activities, coastal lakes are potentially threatened by increased sedimentation rates and relative sea-level increases. The present study analyzed the sedimentary-filling conditions of Itapeva Lake by using the 210Pb geochronology method, which is based on 210Pb and 226Ra activity values obtained from three sediment cores. Measurements of sedimentation rates in the core C3 indicate a strong influence of the drainage of the Três Forquilhas River with values of approximately 3.2 mm.a-1. The sampling points in the center (C2) and north (C1) exhibited significantly lower values of 2.4 and 2.9 mm.a-1, respectively. These values are lower than the rates of relative sea-level increase, which indicate a transitional scenario between the stabilization and sedimentary deficit in the lacustrine burial process. The particle size analysis in the core samples indicates the presence of significant hydrodynamic energy in the sedimentation. The silt fraction is the dominant class, with variations in size ranging from medium to coarse in all samples, followed by the occurrence of fraction sand in relation to clay which presented low concentration, not over 9%. However, an increase in mud content has been observed in the core C3 over the last several decades, which suggests changes in the drainage basin of the Três Forquilhas River due to an increase in sediment production. Urbanization and the introduction of agriculture within the last century are the main reasons for this behaviorLagoas costeiras são ambientes potencialmente ameaçados pelo aumento recente das taxas de sedimentação e elevação relativa do nível do mar. Neste trabalho foram analisadas as condições de preenchimento sedimentar da Lagoa Itapeva utilizando o método geocronológico 210Pb, a partir dos valores da atividade do 210Pb e 226Ra obtidos de três testemunhos geológicos. As taxas de sedimentação medidas no testemunho C3 indicam forte influência da drenagem do Rio Três Forquilhas, com valores na ordem de 3,2 mm.a-1. Os pontos de coleta no centro C2 e norte C1 apresentaram valores sensivelmente menores, 2,4 e 2,9 mm.a-1, respectivamente. Tais valores mostram-se inferiores as taxas de elevação relativa do nível do mar, indicando um cenário transicional entre a estabilização e o déficit sedimentar no processo de preenchimento lacustre. A análise granulométrica nos testemunhos indica a presença de significativa energia hidrodinâmica no processo de sedimentação. A fração silte é a classe dominante, com variação entre o tamanho médio a grosso em todas as amostras, seguida pela ocorrência da fração areia em relação à argila que apresentou baixa concentração, não ultrapassando 9%. Entretanto, foi verificado no testemunho C3 um aumento do teor de lamas nas últimas décadas, o que sugere modificações na bacia de drenagem do Rio Três Forquilhas pelo aumento na produção de sedimentos. A urbanização e a introdução da agricultura no último século são as principais variáveis que explicam este comportamento

Intercomparison of snow depth retrievals over Arctic sea ice from radar data acquired by Operation IceBridge

Since 2009, the ultra-wideband snow radar on Operation IceBridge (OIB; a NASA airborne mission to survey the polar ice covers) has acquired data in annual campaigns conducted during the Arctic and Antarctic springs. Progressive improvements in radar hardware and data processing methodologies have led to improved data quality for subsequent retrieval of snow depth. Existing retrieval algorithms differ in the way the air–snow (a–s) and snow–ice (s–i) interfaces are detected and localized in the radar returns and in how the system limitations are addressed (e.g., noise, resolution). In 2014, the Snow Thickness On Sea Ice Working Group (STOSIWG) was formed and tasked with investigating how radar data quality affects snow depth retrievals and how retrievals from the various algorithms differ. The goal is to understand the limitations of the estimates and to produce a well-documented, long-term record that can be used for understanding broader changes in the Arctic climate system. Here, we assess five retrieval algorithms by comparisons with field measurements from two ground-based campaigns, including the BRomine, Ozone, and Mercury EXperiment (BROMEX) at Barrow, Alaska; a field program by Environment and Climate Change Canada at Eureka, Nunavut; and available climatology and snowfall from ERA-Interim reanalysis. The aim is to examine available algorithms and to use the assessment results to inform the development of future approaches. We present results from these assessments and highlight key considerations for the production of a long-term, calibrated geophysical record of springtime snow thickness over Arctic sea ice