Characteristics and fate of isolated permafrost patches in coastal Labrador, Canada

Bodies of peatland permafrost were examined at five sites along a 300&thinsp;km transect spanning the isolated patches permafrost zone in the coastal barrens of southeastern Labrador. Mean annual air temperatures ranged from +1&thinsp;°C in the south (latitude 51.4°&thinsp;N) to −1.1&thinsp;°C in the north (53.7°&thinsp;N) while mean ground temperatures at the top of the permafrost varied respectively from −0.7 to −2.3&thinsp;°C with shallow active layers (40–60&thinsp;cm) throughout. Small surface offsets due to wind scouring of snow from the crests of palsas and peat plateaux, and large thermal offsets due to thick peat are critical to permafrost, which is absent in wetland and forested and forest–tundra areas inland, notwithstanding average air temperatures much lower than near the coast. Most permafrost peatland bodies are less than 5&thinsp;m thick, with a maximum of 10&thinsp;m, with steep geothermal gradients. One-dimensional thermal modelling for two sites showed that they are in equilibrium with the current climate, but the permafrost mounds are generally relict and could not form today without the low snow depths that result from a heaved peat surface. Despite the warm permafrost, model predictions using downscaled global warming scenarios (RCP2.6, RCP4.5, and RCP8.5) indicate that perennially frozen ground will thaw from the base up and may persist at the southern site until the middle of the 21st century. At the northern site, permafrost is more resilient, persisting to the 2060s under RCP8.5, the 2090s under RCP4.5, or beyond the 21st century under RCP2.6. Despite evidence of peatland permafrost degradation in the study region, the local-scale modelling suggests that the southern boundary of permafrost may not move north as quickly as previously hypothesized.</p

Touch and look: the role of visual-haptic cues for categorical learning in children

Benefits of synchronous presentation of multisensory compared to unisensory cues are well established. However, the generality of such findings to children’s learning with visual and haptic sensory cue pairings is unclear. Children aged six to ten years (N=180) participated in a novel table-top category learning paradigm with visual, haptic or visuo-haptic informative cues. The results indicated that combinations of complimentary visual and haptic cues facilitated learning above unisensory visual cues only in 8-year-old children. Primarily, however, haptic information was found to dominate children’s category learning across ages, particularly in the youngest children (six-year-olds), even with equal discriminability of haptic and visual exemplars. These findings suggest developmental changes in the ability to effectively combine un-related visual and haptic information for categorical learning. Implications for the use of non-pertinent visuohaptic cues in learning tasks within educational settings at different ages, and in particular the dominance of haptic stimuli for children’s learning are discussed

Variability and change in the Canadian cryosphere

Abstract During the International Polar Year (IPY), comprehensive observational research programs were undertaken to increase our understanding of the Canadian polar cryosphere response to a changing climate. Cryospheric components considered were snow, permafrost, sea ice, freshwater ice, glaciers and ice shelves. Enhancement of conventional observing systems and retrieval algorithms for satellite measurements facilitated development of a snapshot of current cryospheric conditions, providing a baseline against which future change can be assessed. Key findings include: 1. surface air temperatures across the Canadian Arctic exhibit a warming trend in all seasons over the past 40 years. A consistent pan-cryospheric response to these warming temperatures is evident through the analysis of multi-decadal datasets; 2. in recent years (including the IPY period) a higher rate of change was observed compared to previous decades including warming permafrost, reduction in snow cover extent and duration, reduction in summer sea ice extent, increased mass loss from glaciers, and thinning and break-up of the remaining Canadian ice shelves. These changes illustrate both a reduction in the spatial extent and mass of the cryosphere and an increase in the temporal persistence of melt related parameters. The observed changes in the cryosphere have important implications for human activity including the close ties of northerners to the land, access to northern regions for natural resource development, and the integrity of northern infrastructure

Limited release of previously-frozen C and increased new peat formation after thaw in permafrost peatlands

Permafrost stores globally significant amounts of carbon (C) which may start to decompose and be released to the atmosphere in form of carbon dioxide (CO 2 ) and methane (CH 4 ) as global warming promotes extensive thaw. This permafrost carbon feedback to climate is currently considered to be the most important carbon-cycle feedback missing from climate models. Predicting the magnitude of the feedback requires a better understanding of how differences in environmental conditions post-thaw, particularly hydrological conditions, control the rate at which C is released to the atmosphere. In the sporadic and discontinuous permafrost regions of north-west Canada, we measured the rates and sources of C released from relatively undisturbed ecosystems, and compared these with forests experiencing thaw following wildfire (well-drained, oxic conditions) and collapsing peat plateau sites (water-logged, anoxic conditions). Using radiocarbon analyses, we detected substantial contributions of deep soil layers and/or previously-frozen sources in our well-drained sites. In contrast, no loss of previously-frozen C as CO 2 was detected on average from collapsed peat plateaus regardless of time since thaw and despite the much larger stores of available C that were exposed. Furthermore, greater rates of new peat formation resulted in these soils becoming stronger C sinks and this greater rate of uptake appeared to compensate for a large proportion of the increase in CH 4 emissions from the collapse wetlands. We conclude that in the ecosystems we studied, changes in soil moisture and oxygen availability may be even more important than previously predicted in determining the effect of permafrost thaw on ecosystem C balance and, thus, it is essential to monitor, and simulate accurately, regional changes in surface wetness

Depth cues and perceived audiovisual synchrony of biological motion

Due to their different propagation times, visual and auditory signals from external events arrive at the human sensory receptors with a disparate delay. This delay consistently varies with distance, but, despite such variability, most events are perceived as synchronic. There is, however, contradictory data and claims regarding the existence of compensatory mechanisms for distance in simultaneity judgments. Principal Findings: In this paper we have used familiar audiovisual events – a visual walker and footstep sounds – and manipulated the number of depth cues. In a simultaneity judgment task we presented a large range of stimulus onset asynchronies corresponding to distances of up to 35 meters. We found an effect of distance over the simultaneity estimates, with greater distances requiring larger stimulus onset asynchronies, and vision always leading. This effect was stronger when both visual and auditory cues were present but was interestingly not found when depth cues were impoverished. Significance: These findings reveal that there should be an internal mechanism to compensate for audiovisual delays, which critically depends on the depth information available.FEDERFundação para a Ciência e a Tecnologia (FCT

Cloning, purification and characterisation of a recombinant purine nucleoside phosphorylase from Bacillus halodurans Alk36

A purine nucleoside phosphorylase from the alkaliphile Bacillus halodurans Alk36 was cloned and overexpressed in Escherichia coli. The enzyme was purified fivefold by membrane filtration and ion exchange. The purified enzyme had a Vmax of 2.03 × 10−9 s −1 and a Km of 206 μM on guanosine. The optimal pH range was between 5.7 and 8.4 with a maximum at pH 7.0. The optimal temperature for activity was 70°C and the enzyme had a half life at 60°C of 20.8 h

‘No memory, no desire’: psychoanalysis in Brazil during repressive times

Until recently, the growth and significance of Brazilian psychoanalysis has been neglected in histories of psychoanalysis. Not only is this history long and rich in its professional and cultural dimensions, but there was an especially important ‘event’ – the so-called ‘Cabernite-Lobo affair’ – that took place during the period of the military dictatorship, which can be seen as dramatising some of the issues concerning the erasure of memory in psychoanalysis, especially in connection with political difficulties. In this paper, we provide an outline of the origins and dissemination of psychoanalysis in Brazil before looking again at the Cabernite-Lobo affair in order to examine in a situated way how psychoanalysis engages with political extremism, and particularly to explore the consequences of an unthinking generalisation of the idea of ‘neutrality’ from the consulting room to the institutional setting. We draw especially on Brazilian papers in Portuguese, which have not been accessible in the English-language psychoanalytic literature

Sex Differences in Social Attention in Infants at Risk for Autism

We studied visual attention to emotional faces in 10-month-old infant siblings of children with ASD (ASD-sibs; N = 70) and a siblings of typically developing children (N = 29) using static stimuli. Contrary to our predictions, we found no evidence for atypical gaze behavior in ASD-sibs when boys and girls were analyzed together. However, a sex difference was found in ASD-sibs' visual attention to the mouth. Male ASD-sibs looked more at the mouth across emotions compared to male controls and female ASD-sibs. In contrast, female ASD-sibs looked less at the mouth compared to female controls. These findings suggest that some aspects of early emerging atypical social attention in ASD-sibs may be sex specific