scholarly journals The Physical Processes involved in the Melting of Icebergs (Invited paper)

1980 ◽  
Vol 1 ◽  
pp. 97-101 ◽  
Author(s):  
Herbert E. Huppert
Keyword(s):  
Current Understanding ◽  
Field Observations ◽  
Ambient Water ◽  
Physical Processes ◽  
Water Line ◽  
The Third ◽  
Short Summary ◽  
Melt Water ◽  
Wave Induced ◽  
Horizontal Layers

The causes of iceberg deterioration can be discussed under three broad headings: wave-induced melting at the water line; breaking; and melting at the top, bottom, and sides. A short summary of current understanding under the first two headings is presented. It is then argued, under the third heading, that the melt rate at the sides of a tabular Antarctic iceberg is likely to exceed that at the top and bottom. The behaviour of the entraining plume which forms at the side of an iceberg when it melts in water of uniform salinity is outlined. Another form of convection, occurring when the ambient water is stratified, is then described; in this case the melt water spreads out in a series of almost horizontal layers. Finally, field observations on iceberg melting are discussed.

A deflationist theory of intentionality?

2005 ◽  
Vol 13 (1) ◽  
pp. 73-90
Author(s):  
Sebastian Knell
Keyword(s):  
Mental States ◽  
Specific Role ◽  
Philosophical Debate ◽  
Attitude Ascription ◽  
Attitude Ascriptions ◽  
Theories Of Truth ◽  
De Re ◽  
The Third ◽  
Short Summary

The paper presents an interpretation of Brandom’s analysis of de re specifying attitude-ascriptions. According to this interpretation, his analysis amounts to a deflationist conception of intentionality. In the first section I sketch the specific role deflationist theories of truth play within the philosophical debate on truth. Then I describe some analogies between the contemporary constellation of competing truth theories and the current confrontation of controversial theories of intentionality. The second section gives a short summary of Brandom’s analysis of attitude-ascription, focusing on his account of the grammar of de re ascriptions of belief. The third section discusses in detail those aspects of his account from which a deflationist conception of intentionality may be derived, or which at least permit such a conception. In the proposed interpretation of Brandom’s analysis, the vocabulary expressing the representational directedness of thought and talk does not describe a genuine property of mental states, but has an alternative descriptive function and in addition contains a performative and a meta­descriptive element.

scholarly journals A Field Study of Brine Drainage and Oil Entrainment in First-Year Sea Ice

1979 ◽  
Vol 22 (88) ◽  
pp. 473-502 ◽  
Author(s):  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Growth And Development ◽  
Salt Transport ◽  
First Year ◽  
Field Observations ◽  
Melt Pond ◽  
Ice Surface ◽  
Melt Ponds ◽  
Brine Channel ◽  
Horizontal Layers

AbstractFrom field observations this paper describes the growth and development of first-year sea ice and its interaction with petroleum. In particular, when sea ice initially forms, there is an upward salt transport so that the ice surface has a highly saline layer, regardless of whether the initial ice is frazil, columnar, or slush ice. When the ice warms in the spring, because of the eutectic condition, the surface salt liquifies and drains through the ice, leading to the formation of top-to-bottom brine channels and void spaces in the upper part of the ice. If oil is released beneath winter ice, then the oil becomes entrained in thin lenses within the ice. In the spring, this oil flows up to the surface through the newly-opened brine channels and distributes itself within the brine-channel feeder systems, on the ice surface, and in horizontal layers in the upper part of the ice. The paper shows that these layers probably form from the interaction of the brine drainage with the percolation of melt water from surface snow down into the ice and the rise of the oil from below. Finally in the summer, the oil on the surface leads to melt-pond formation. The solar energy absorbed by the oil on the surface of these melt ponds eventually causes the melt pond to melt through the ice, and the oil is again released into the ocean.

scholarly journals Field Observations and Experimental and Theoretical Studies on the Superimposed Ice of McCall Glacier, Alaska

1976 ◽  
Vol 16 (74) ◽  
pp. 135-149 ◽  
Author(s):  
Gorow Wakahama ◽  
Daisuke Kuroiwa ◽  
Tatsuo Hasemi ◽  
Carl S. Benson
Keyword(s):  
Growth Rate ◽  
Temperature Distribution ◽  
Laboratory Experiment ◽  
Observational Data ◽  
Initial Temperature ◽  
Field Observations ◽  
Snow Melting ◽  
Initial Temperature Distribution ◽  
Run Off ◽  
Melt Water

AbstractThe formation of superimposed ice in the accumulation area of sub-polar glaciers plays an important role in the heat and mass balance of the glaciers. In order to study the process of superimposed ice formation in detail, field observations were conducted on McCall Glacier, a sub-polar glacier in Arctic Alaska. It was found that the approximate thickness of superimposed ice formed in a whole summer was 20 cm in the upper region and 30—40 cm in the lower region of the accumulation area of the glacier. This difference in thickness may be attributed to the difference in the temperature of the underlying ice and the rate of supply of melt water. The ratio of the amount of superimposed ice formed in the accumulation area from May to July in 1972 to the total amount of melt was determined. Approximately 50% of the total melt water was discharged from the glacier as run-off water, and the remainder contributed to the formation of superimposed ice.An experimental study on the artificial formation of superimposed ice was conducted in the cold laboratory to obtain the ratio of superimposed ice, that of run-off water, and that of free water suspended between snow grains, to the total amount of melt water produced in the snow. The ratios obtained in the laboratory experiment agree fairly well with those derived from the observational data on McCall Glacier.Numerical calculations were conducted to examine the relationship between the growth rate of superimposed ice, the rale of snow melting, the rate of discharge of excess melt-water, and the temperature of the underlying ice. Calculations were made in reference to both the laboratory experiment and the field observations on McCall Glacier. It was found that the predominant factors controlling the growth rate or the total amount of superimposed ice in a sub-polar glacier are the rate of supply of melt water to the snow-ice interface and the initial temperature distribution in the underlying ice. By using the present calculation, it may be possible to estimate the growth rate, the total amount of superimposed ice, and the ratio of superimposed ice to the total amount of melting in the accumulation area of any sub-polar glacier, if observational data on the initial temperature distribution in ice and the rate of snow melting at the snow surface are available.

scholarly journals Coupled Model Simulations of the West African Monsoon System: Twentieth- and Twenty-First-Century Simulations

2006 ◽  
Vol 19 (15) ◽  
pp. 3681-3703 ◽  
Author(s):  
Kerry H. Cook ◽  
Edward K. Vizy
Keyword(s):  
Twentieth Century ◽  
West African Monsoon ◽  
West African ◽  
First Century ◽  
Gulf Of Guinea ◽  
Physical Processes ◽  
The West ◽  
African Monsoon ◽  
The Third ◽  
Twenty First Century

Abstract The ability of coupled GCMs to correctly simulate the climatology and a prominent mode of variability of the West African monsoon is evaluated, and the results are used to make informed decisions about which models may be producing more reliable projections of future climate in this region. The integrations were made available by the Program for Climate Model Diagnosis and Intercomparison for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. The evaluation emphasizes the circulation characteristics that support the precipitation climatology, and the physical processes of a “rainfall dipole” variability mode that is often associated with dry conditions in the Sahel when SSTs in the Gulf of Guinea are anomalously warm. Based on the quality of their twentieth-century simulations over West Africa in summer, three GCMs are chosen for analysis of the twenty-first century integrations under various assumptions about future greenhouse gas increases. Each of these models behaves differently in the twenty-first-century simulations. One model simulates severe drying across the Sahel in the later part of the twenty-first century, while another projects quite wet conditions throughout the twenty-first century. In the third model, warming in the Gulf of Guinea leads to more modest drying in the Sahel due to a doubling of the number of anomalously dry years by the end of the century. An evaluation of the physical processes that cause these climate changes, in the context of the understanding about how the system works in the twentieth century, suggests that the third model provides the most reasonable projection of the twenty-first-century climate.

scholarly journals Summary and Conclusions

2021 ◽  
pp. 221-225
Author(s):  
Donald V. Reames
Keyword(s):  
Magnetic Fields ◽  
Source Parameters ◽  
Physical Models ◽  
Current Understanding ◽  
Energy Spectra ◽  
Physical Processes ◽  
Indelible Mark ◽  
Time Profiles

AbstractIn this chapter we summarize our current understanding of SEPs, of properties of the sites of their origin and of the physical processes that accelerate or modify them. These processes can leave an indelible mark on the abundances of elements, isotopes, ionization states, anisotropies, energy spectra and time profiles of the SEPs. Transport of the ions to us along magnetic fields can impose new variations in large events or even enhance the visibility of the source parameters as the SEPs expand into the heliosphere. We lack physical models that can follow the complexity of SEP abundance variations.

Fisheries and Aquaculture

2020 ◽  
Keyword(s):  
Present Knowledge ◽  
Current Understanding ◽  
Fishing Communities ◽  
Small Scale ◽  
Crustacean Species ◽  
The Third ◽  
Challenges And Opportunities ◽  
Crustacean Fisheries

This volume examines fisheries and aquaculture. The chapters in this volume synthesize the current understanding of the diverse topics in fisheries and aquaculture. The first part of the book explores worldwide crustacean fisheries and concludes with two chapters on harvested crustaceans that are usually not within the focus of the mainstream fisheries research, possibly because they are caught by local fishing communities in small-scale operations and sold locally as subsistence activity. In the second part of the book, the authors explore the variety of cultured crustacean species. The chapters of the third part of the volume focus on important challenges and opportunities, including diseases and parasitism, the use of crustaceans as bioindicators, and their role in biotechnology. Collectively, these 19 chapters provide a thorough exposition of the present knowledge across the major themes in crustacean fisheries and aquaculture.

Fostering comprehension and integration in mycorrhiza biology: conceptual scaffolding as an aid in teaching and exploration,

Botany ◽  
2017 ◽  
Vol 95 (10) ◽  
pp. 983-1003 ◽  
Author(s):  
Hugues B. Massicotte ◽  
Frédérique C. Guinel
Keyword(s):  
Incremental Learning ◽  
Mycorrhizal Fungi ◽  
Vascular Plants ◽  
Plant Root ◽  
Learning Difficulty ◽  
The Third ◽  
Short Summary ◽  
New Information ◽  
Potential Applications ◽  
Senior Students

Over the last decade, we have witnessed extraordinary progress in the understanding of molecular dialogues between the partners in plant root mutualisms and, as such, a considerable amount of new information now needs to be integrated into an already significant body of literature. The topic of symbiosis has become difficult to explore in a teaching venue, as there is seemingly so much to discuss, and yet students are truly interested in the discipline because of its potential applications in conservation, sustainable agriculture, and forestry. In this minireview targeted to instructors, senior students, and scientists, we offer a means of teaching the symbioses between mycorrhizal fungi and vascular plants, whereby we propose a conceptual staircase with three levels of incremental learning difficulty. At the first level, we describe the fundamentals of mycorrhizas with special emphasis on the plant–fungus interface. At the second level, we focus on the pre-communication between the two partners. At the third level, we discuss the physiology of the interface in terms of agriculture and forestry. At the end of each level, we provide a short summary where the most important concepts have been outlined for an instructor. As well, throughout the text, we raise questions of interest to the field at large.

STUDIES ON DIPTEROUS PARASITES OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (CLEM.) (LEPIDOPTERA: TORTRICIDAE): IV. MADREMYIA SAUNDERSII (WILL.) (DIPTERA: TACHINIDAE)

1954 ◽  
Vol 32 (4) ◽  
pp. 314-323 ◽  
Author(s):  
H. C. Coppel ◽  
M. G. Maw
Keyword(s):  
Choristoneura Fumiferana ◽  
Adult Emergence ◽  
The Body ◽  
Field Observations ◽  
Eastern Canada ◽  
The Third ◽  
Egg Deposition ◽  
Wide Range ◽  
General Field ◽  
Native Parasite

Studies initiated in British Columbia in 1943 showed that Madremyia saundersii (Will.), a native parasite with a wide range of lepidopterous hosts in North America, was a parasite of the spruce bud worm, Choristoneura fumiferana (Clem.). The parasite has been obtained each year since then in moderate numbers and released in infested areas of Eastern Canada. M. saundersii deposits macrotype eggs on the integument of host larvae. The first stage larvae penetrate the integument of the host. The larvae attach themselves to tracheal trunks, where they remain throughout the first and second stages, but during the third feeding stage they wander freely within the body, devouring all the contents. The period from egg deposition to adult emergence was 17 to 23 days under laboratory conditions. The life history and habits of the insect are outlined, and are supplemented by general field observations. The immature stages of the parasite are illustrated and described.

Factor Markets in Babylonia from the Late Seventh to the Third Century BCE

2014 ◽  
Vol 57 (2) ◽  
pp. 173-202 ◽  
Author(s):  
Michael Jursa
Keyword(s):  
Economic Development ◽  
Labour Market ◽  
Agricultural Land ◽  
Quantitative Information ◽  
Commodity Markets ◽  
Current Understanding ◽  
Third Century ◽  
The Third ◽  
Socio Economic Development ◽  
Factor Markets

Abstract This paper studies the evidence for the existence of a labour market, a market for agricultural land, and a market for capital in Babylonia from the sixth to the third century bce. The argument is informed by our current understanding of the performance of Babylonian commodity markets, for which abundant quantitative information is available. I attempt to establish a connection between the general political and socio-economic development in Babylonia from the sixth century onwards and the increase and decrease of the role that can be attributed to factor markets.

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