The presence of melt ponds on the surface of Arctic sea ice significantly reduces its albedo, inducing a positive feedback leading to sea ice thinning. While the role of melt ponds in enhancing the summer melt of sea ice is well known, their impact on suppressing winter freezing of sea ice has, hitherto, received less attention. Melt ponds freeze by forming an ice lid at the upper surface, which insulates them from the atmosphere and traps pond water between the underlying sea ice and the ice lid. The pond water is a store of latent heat, which is released during refreezing. Until a pond freezes completely, there can be minimal ice growth at the base of the underlying sea ice. In this work, we present a model of the refreezing of a melt pond that includes the heat and salt balances in the ice lid, trapped pond, and underlying sea ice. The model uses a two-stream radiation model to account for radiative scattering at phase boundaries. Simulations and related sensitivity studies suggest that trapped pond water may survive for over a month. We focus on the role that pond salinity has on delaying the refreezing process and retarding basal sea ice growth. We estimate that for a typical sea ice pond coverage in autumn, excluding the impact of trapped ponds in models overestimates ice growth by up to 265 million km 3 , an overestimate of 26%.

Purpose-The spatio-temporal index (STI) is one measure of variability. As currently implemented, kinematic data are used, requiring equipment that cannot be used with some patient groups or in scanners. An experiment is reported that addressed whether STI can be extended to an audio measure of sound pressure of the speech envelope over time, that did not need specialized equipment.Method-STI indices of variability were obtained from lip track (L-STI) and amplitude envelope (E-STI) signals. These measures were made concurrent whilst either fluent speakers or speakers who stutter repeated "Buy Bobby a puppy" 20 times.Results-L-STI and E-STI correlated significantly. STI reduced with age for both L-STI and E-STI. E-STI scores and L-STI scores discriminated successfully between fluent speakers and speakers who stutter. Conclusion-The amplitude envelope over time STI scores can be used to obtain an STI score. This STI score can be used in situations where lip movement STI scores are precluded.

[1] Rafting is one of the important deformation mechanisms of sea ice. This process is widespread in the north Caspian Sea, where multiple rafting produces thick sea ice features, which are a hazard to offshore operations. Here we present a one-dimensional, thermal consolidation model for rafted sea ice. We consider the consolidation between the layers of both a two-layer and a three-layer section of rafted sea ice. The rafted ice is assumed to be composed of layers of sea ice of equal thickness, separated by thin layers of ocean water. Results show that the thickness of the liquid layer reduced asymptotically with time, such that there always remained a thin saline liquid layer. We propose that when the liquid layer is equal to the surface roughness the adjacent layers can be considered consolidated. Using parameters representative of the north Caspian, the Arctic, and the Antarctic, our results show that for a choice of standard parameters it took under 15 h for two layers of rafted sea ice to consolidate. Sensitivity studies showed that the consolidation model is highly sensitive to the initial thickness of the liquid layer, the fraction of salt release during freezing, and the height of the surface asperities. We believe that further investigation of these parameters is needed before any concrete conclusions can be drawn about rate of consolidation of rafted sea ice features.

Three schemes for assessing stuttering were compared. They differed with respect to whether they included whole-word repetitions as characteristics more typical of stuttering. Persistent and recovered groups of children were examined to see whether: (1) one of the schemes differentiated the groups better than others; (2) more and less typical of stuttering characteristics changed over ages in different ways for the groups; and (3) the changes over ages of more and less typical of stuttering classes depended on word type. Twenty-six children who stuttered were classified as persistent or recovered and recorded at three ages between 8-12+ years. Stuttering characteristics were obtained according to the three schemes. The results show: (1) All schemes distinguished persistent, from recovered, children. (2) The proportion of less typical of stuttering characteristics increased and more typical of stuttering characteristics decreased over age for recovered children for all three schemes (there was no change for persistent children). (3) The increased proportion of less typical of stuttering characteristics for the recovered children across age was more apparent for one-syllable content words than one-syllable function words.

LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The "spines" which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone.