The Paradox of Nocturnality in Lizards

Paradoxically, nocturnal lizards prefer substantially higher body temperatures than are achievable at night and are therefore active at thermally suboptimal temperatures. In this study, potential physiological mechanisms were examined that may enable nocturnal lizards to counteract the thermal handicap of activity at low temperatures: 1) daily rhythms of metabolic rate, 2) metabolic rate at low and high temperatures, 3) locomotor energetics, and 4) biochemical adaptation. A multi-species approach was used to separate evolutionary history of the species from any potential links between physiology and activity period. Four to eight species of lizards, encompassing nocturnal and diurnal lizards from the families Diplodactylidae and Scincidae, were used for all physiological measurements. Three daily patterns of metabolic rate (VO2) were apparent depending on the species: 24 h cycles, 12 h cycles, and no daily cycle. The daily patterns of VO2 and peak VO2 did not always coincide with the activity period of the species. All nocturnal lizards tested had a lower energetic cost of locomotion (Cmin) than diurnal lizards. Diurnal lizards from New Zealand also had low Cmin values when compared with nocturnal geckos and diurnal lizards from lower latitudes. Thus, a low Cmin appears to be related to activity at low temperatures rather than specifically to nocturnality. However, more data are required on lizards from high latitudes, including more New Zealand lizards, before the generality of this pattern can be confirmed. Also, based on correlations with lizards active at warmer temperatures, a low Cmin only partially offsets the thermal handicap imposed on lizards that are active at low temperatures. Nocturnal lizards were found to have lower thermal sensitivities of metabolism (lower Q10 values) than diurnal lizards, indicating that their energy-dependent activity was not as sensitive to changes in environmental temperature. The similarity of other metabolic processes among species with differing activity periods may be partly explained by the ability of nocturnal species to thermoregulate to achieve higher temperatures during the day. The amplitudes of daily VO2 cycles and mass-specific VO2 did not differ among nocturnal and diurnal New Zealand lizards at low temperatures. The specific activity of the glycolytic enzyme lactate dehydrogenase (LDH) isolated from the tail muscle of lizards was also comparable among nocturnal and diurnal lizards over a range of biologically relevant temperatures. Thus, activity of lizards at low temperatures is not enabled by lower energy requirements over a 24 h period, elevation of metabolic rates, or biochemical adaptation of LDH to specific temperatures. These results confirm that locomotion is more efficient in nocturnal lizards and diurnal lizards from New Zealand than lizards from elsewhere, but that other metabolic processes do not appear to differ among species. Additional physiological and behavioural adaptations may exist that complement the increased efficiency of locomotion, thus enabling nocturnal lizards to be active at low temperatures

Multi-wavelength observations of 2HWC J1928+177: dark accelerator or new TeV gamma-ray binary?

2HWC J1928+177 is a Galactic TeV gamma-ray source detected by the High Altitude Water Cherenkov (HAWC) Observatory up to ~ 56 TeV. The HAWC source, later confirmed by H.E.S.S., still remains unidentified as a dark accelerator since there is no apparent supernova remnant or pulsar wind nebula detected in the lower energy bands. The radio pulsar PSR J1928+1746, coinciding with the HAWC source position, has no X-ray counterpart. Our SED modeling shows that inverse Compton scattering in the putative pulsar wind nebula can account for the TeV emission only if the unseen nebula is extended beyond r ~ 4 [arcmin]. Alternatively, TeV gamma rays may be produced by hadronic interactions between relativistic protons from an undetected supernova remnant associated with the radio pulsar and a nearby molecular cloud G52.9+0.1. NuSTAR and Chandra observations detected a variable X-ray point source within the HAWC error circle, potentially associated with a bright IR source. The X-ray spectra can be fitted with an absorbed power-law model with $N_{\rm H} = (9\pm3)\times10^{22}$ cm$^{-2}$ and $\Gamma_X = 1.6\pm0.3$ and exhibit long-term X-ray flux variability over the last decade. If the X-ray source, possibly associated with the IR source (likely an O star), is the counterpart of the HAWC source, it may be a new TeV gamma-ray binary powered by collisions between the pulsar wind and stellar wind. Follow-up X-ray observations are warranted to search for diffuse X-ray emission and determine the nature of the HAWC source.Comment: accepted to ApJ, 8 pages, 7 figure

Tracking global population trends: population time-series data and a Living Planet Index for reptiles

Effective conservation action relies on access to the best-available species data. Reptiles have often been overlooked in conservation prioritization, especially because of a paucity of population data. Using data for 549 reptile populations representing 194 species from the Living Planet database, we provide the first detailed analysis of this database for a specific taxonomic group. We estimated an average global decline in reptile populations of 54-55% between 1970 and 2012. Disaggregated indices at taxonomic, system, and biogeographical levels showed trends of decline, often with wide confidence intervals because of a prevalence of short time series. We assessed gaps in our reptile time-series data and examined what types of publication they primarily originated from to provide an overview of the range of data sources captured in the Living Planet database. Data were biased toward crocodilians and chelonians, with only 1% and 2% of known lizard and snake species represented, respectively. Population time-series data stemmed primarily from published ecological research (squamates) and data collected for conservation management (chelonians and crocodilians). We recommend exploration of novel survey and analytical techniques to increase monitoring of reptiles, especially squamates, over time. Open access publication and sharing of data sets are vital to improve knowledge of reptile status and trends, aided by the provision of properly curated databases and data-sharing agreements. Such collaborative efforts are vital to effectively address global reptile declines

Spectral tunability of a plasmonic antenna with a dielectric nanocrystal

We show that the positioning of a nanometer length scale dielectric object, such as a diamond nanocrystal, in the vicinity of a gold bowtie nanoantenna can be used to tune the plasmonic mode spectrum on the order of a linewidth. We further show that the intrinsic luminescence of gold enhanced in the presence of nanometer-scale roughness couples efficiently to the plasmon mode and carries the same polarization anisotropy. Our findings have direct implications for cavity quantum electrodynamics related applications of hybrid antenna-emitter complexes.Comment: 10 pages, 3 figure

New insights into Eastern Beringian mortuary behavior: A terminal Pleistocene double infant burial at Upward Sun River

Here we report on the discovery of two infant burials dating to 11,500 calibrated years (cal) B.P. at the Upward Sun River site in central Alaska. The infants were interred in a pit feature with associated organic and lithic grave goods, including the earliest known North American hafted bifaces with decorated antler foreshafts. Skeletal and dental analyses indicate that Individual 1 died shortly after birth and Individual 2 was a late-term fetus, making these the youngest-aged late Pleistocene individuals known for the Americas and the only known prenate, offering, to our knowledge, the first opportunity to explore mortuary treatment of the youngest members of a terminal Pleistocene North American population. This burial was situated 40 cm directly below a cremated 3-y-old child previously discovered in association with a central hearth of a residential feature. The burial and cremation are contemporaneous, and differences in body orientation, treatment, and associated grave goods within a single feature and evidence for residential occupation between burial episodes indicate novel mortuary behaviors. The human remains, grave goods, and associated fauna provide rare direct data on organic technology, economy, seasonality of residential occupations, and infant/child mortality of terminal Pleistocene Beringians

Direct interaction between the Gulf Stream and the shelfbreak south of New England

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 2 (2012): 553, doi:10.1038/srep00553.Sea surface temperature imagery, satellite altimetry, and a surface drifter track reveal an unusual tilt in the Gulf Stream path that brought the Gulf Stream to 39.9°N near the Middle Atlantic Bight shelfbreak—200 km north of its mean position—in October 2011, while a large meander brought Gulf Stream water within 12 km of the shelfbreak in December 2011. Near-bottom temperature measurements from lobster traps on the outer continental shelf south of New England show distinct warming events (temperature increases exceeding 6°C) in November and December 2011. Moored profiler measurements over the continental slope show high salinities and temperatures, suggesting that the warm water on the continental shelf originated in the Gulf Stream. The combination of unusual water properties over the shelf and slope in late fall and the subsequent mild winter may affect seasonal stratification and habitat selection for marine life over the continental shelf in 2012.Profiler data were made available by the Ocean Observatory Initiative (OOI) during the construction phase of the project. The OOI is funded by the National Science Foundation and managed by the Consortium for Ocean Leadership. Drifter data were provided by Tim Shaw and David Calhoun at Cape Fear Community College.GGGwas supported by NSFGrant OCE-1129125. RET was supported by the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Cooperative Institute for the North Atlantic Region. MA was supported by the Penzance Endowed Fund in Support of Assistant Scientists

Evolutionary biology and anthropology suggest biome reconstitution as a necessary approach toward dealing with immune disorders

Industrialized society currently faces a wide range of non-infectious, immune-related pandemics. These pandemics include a variety of autoimmune, inflammatory and allergic diseases that are often associated with common environmental triggers and with genetic predisposition, but that do not occur in developing societies. In this review, we briefly present the idea that these pandemics are due to a limited number of evolutionary mismatches, the most damaging being ‘biome depletion’. This particular mismatch involves the loss of species from the ecosystem of the human body, the human biome, many of which have traditionally been classified as parasites, although some may actually be commensal or even mutualistic. This view, evolved from the ‘hygiene hypothesis’, encompasses a broad ecological and evolutionary perspective that considers host-symbiont relations as plastic, changing through ecological space and evolutionary time. Fortunately, this perspective provides a blueprint, termed 'biome reconstitution', for disease treatment and especially for disease prevention. Biome reconstitution includes the controlled and population-wide reintroduction (i.e. domestication) of selected species that have been all but eradicated from the human biome in industrialized society and holds great promise for the elimination of pandemics of allergic, inflammatory and autoimmune diseases

The experience of beauty derived from sorrow

We studied the neural mechanisms that are engaged during the experience of beauty derived from sorrow and from joy, two experiences that share a common denominator (beauty) but are linked to opposite emotional valences. Twenty subjects viewed and rerated, in a functional magnetic resonance imaging scanner, 120 images which each had classified into the following four categories: beautiful and sad; beautiful and joyful; neutral; ugly. The medial orbito-frontal cortex (mOFC) was active during the experience of both types of beauty. Otherwise, the two experiences engaged different parts of the brain: joyful beauty engaged areas linked to positive emotions while sorrowful beauty engaged areas linked to negative experiences. Separate regions of the cerebellum were engaged during experience of the two conditions. A functional connectivity analysis indicated that the activity within the mOFC was modulated by the supplementary motor area/middle cingulate cortex, known to be engaged during empathetic experiences provoked by other peoples' sadness

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available

Spirit, mind and body: the archaeology of monastic healing

Archaeology and material culture are used in this chapter to consider how monastic experience responded to illness, ageing and disability. The approach taken is influenced by the material study of religion, which interrogates how bodies and things engage to construct the sensory experience of religion, and by practice-based approaches in archaeology, which examine the active role of space and material culture in shaping religious agency and embodiment. The archaeology of monastic healing focuses on the full spectrum of healing technologies, from managing the body in order to prevent illness, through to the treatment of the sick and preparation of the corpse for burial