A non-destructive method for measuring the salinity and solid fraction of growing sea ice in situ

We describe an instrument developed to make in situ measurements of salinity and solid-fraction profiles in growing sea ice. The vertical resolution of the measurements is up to a few millimeters, with a temporal resolution of up to fractions of a second. The technique is based on impedance measurements between platinum wires around which sea ice grows. Data obtained using this instrument in laboratory experiments are in good agreement with theoretical predictions. In a field test in the Arctic, the bulk salinity of growing sea ice has been measured in situ throughout the whole depth of the ice layer. The data are compared with bulk salinities obtained from ice cores, and confirm the general understanding that the bulk salinity in ice-core studies is significantly underestimated in the lower parts of the cores. The approach can also be used in other glaciological applications and for general studies of two-phase, two-component porous media

Computerised speechreading training for deaf children: A randomised controlled trial

Purpose: We developed and evaluated in a randomised controlled triala computerised speechreading training programme to determine a) whether it is possible to train speechreading in deaf children and b) whether speechreading training results in improvements in phonological and reading skills.Previous studies indicate a relationship between speechreading and reading skill and further suggest this relationshipmay be mediated by improved phonological representations. This is important since many deaf children find learning to read to be very challenging. Method: Sixty-six deaf 5-7 year olds were randomised into speechreading and maths training arms. Each training programme was comprised of10 minutesessionsa day, 4 days a week for 12 weeks. Children were assessed on a battery of language and literacy measures before training, immediately after training, 3 months and 10 months after training. Results: We found no significant benefits for participants who completed the speechreading training, compared to those who completed the maths training, on the speechreading primary outcome measure. However, significantly greater gains were observed in the speechreading training group on one of the secondary measures of speechreading. There was also some evidence of beneficial effects of the speechreading training on phonological representations, however these effects were weaker. No benefits were seen toword reading. Conclusions: Speechreading skill is trainable in deaf children. However, to support early reading, training may need to be longer or embedded in a broader literacy programme. Nevertheless, a training tool that can improve speechreading is likely to be of great interest to professionals working with deaf children

Ice-lens formation and geometrical supercooling in soils and other colloidal materials

We present a new, physically-intuitive model of ice-lens formation and growth during the freezing of soils and other dense, particulate suspensions. Motivated by experimental evidence, we consider the growth of an ice-filled crack in a freezing soil. At low temperatures, ice in the crack exerts large pressures on the crack walls that will eventually cause the crack to split open. We show that the crack will then propagate across the soil to form a new lens. The process is controlled by two factors: the cohesion of the soil, and the geometrical supercooling of the water in the soil; a new concept introduced to measure the energy available to form a new ice lens. When the supercooling exceeds a critical amount (proportional to the cohesive strength of the soil) a new ice lens forms. This condition for ice-lens formation and growth does not appeal to any ad hoc, empirical assumptions, and explains how periodic ice lenses can form with or without the presence of a frozen fringe. The proposed mechanism is in good agreement with experiments, in particular explaining ice-lens pattern formation, and surges in heave rate associated with the growth of new lenses. Importantly for systems with no frozen fringe, ice-lens formation and frost heave can be predicted given only the unfrozen properties of the soil. We use our theory to estimate ice-lens growth temperatures obtaining quantitative agreement with the limited experimental data that is currently available. Finally we suggest experiments that might be performed in order to verify this theory in more detail. The theory is generalizable to complex natural-soil scenarios, and should therefore be useful in the prediction of macroscopic frost heave rates.Comment: Submitted to PR

Reply to 'Broaden research on the human dimensions of climate change'

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The Financial and Psychosocial Impact of Medicinal Cannabis

Introduction: Therapeutic utilization of medicinal cannabis for symptom management in oncology patients is a burgeoning area of research focus. We hypothesize that medicinal cannabis use can result in subjective improvements in quality of life (QOL) metrics for cancer patients. Methods: Adult palliative care patients at a medical oncology clinic are consented to the study after being certified to access medicinal cannabis. After three months, subjective changes in QOL, including well-being, financial burden, pain, chemotherapy induced nausea and vomiting (CINV), and other categories are recorded via telephone interview. Responses are documented with a numerical Likert scale (from 1-5, with a score of 1 = greatly decreased satisfaction, and 5 = greatly increased satisfaction; a score of 3 is no change from baseline). Scores \u3e3.5 were deemed meaningful in terms of improvement. Results: An aggregate of 35 patient scores showed meaningful increases in subjective satisfaction across most metrics. Satisfaction with CINV symptoms showed the most marked improvement, with an average score of 3.63. While pain scores were similar at 3.53, more general QOL metrics were lower, at 3.46. Most patients did not find the cost to be burdensome, with an average score of 3.03. Discussion: The initial 35 interviews of our desired n of 120 suggest that medicinal cannabis may provide analgesic, antiemetic, and anxiolytic benefits for cancer patients. We anticipate that additional interviews will follow this pattern. If so, our study could bolster the evidence that therapeutic use of medicinal cannabis may be helpful for patients undergoing cancer treatment

The case for a dynamic contact angle in containerless solidification

Abstract Containerless solidification, in which the melt is confined by its own surface tension, is an important technique by which very pure materials can be produced. The form of the solidified product is sensitive to conditions at the tri-junction between the solid, the melt and the surrounding vapor. An understanding of the dynamics of tri-junctions is therefore crucial to the modelling and prediction of containerless solidification systems. We consider experimentally and analytically the simple system of a liquid droplet solidifying on a cold plate. Our experimental results provide a simple test of tri-junction conditions which can be used in theoretical analyses of more complicated systems. A new dynamical boundary condition at the tri-junction is introduced here and explains the surprising features of solidified water droplets on a cold surface

Relationship between conservation biology and ecology shown through machine reading of 32,000 articles

Conservation biology was founded on the idea that efforts to save nature depend on a scientific understanding of how it works. It sought to apply ecological principles to conservation problems. We investigated whether the relationship between these fields has changed over time through machine reading the full texts of 32,000 research articles published in 16 ecology and conservation biology journals. We examined changes in research topics in both fields and how the fields have evolved from 2000 to 2014. As conservation biology matured, its focus shifted from ecology to social and political aspects of conservation. The 2 fields diverged and now occupy distinct niches in modern science. We hypothesize this pattern resulted from increasing recognition that social, economic, and political factors are critical for successful conservation and possibly from rising skepticism about the relevance of contemporary ecological theory to practical conservation

A model for the consolidation of rafted sea ice

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