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A. Thorpe

Publications and source records attributed to A. Thorpe.

5 recordsLinked to original sources

Effects of climate and land-use changes on fish catches across lakes at a global scale

Globally, our knowledge on lake fisheries is still limited despite their importance to food security and livelihoods. Here we show that fish catches can respond either positively or negatively to climate and land-use changes, by analyzing time-series data (1970–2014) for 31 lakes across five continents. We find that effects of a climate or land-use driver (e.g., air temperature) on lake environment could be relatively consistent in directions, but consequential changes in a lake-environmental factor (e.g., water temperature) could result in either increases or decreases in fish catch in a given lake. A subsequent correlation analysis indicates that reductions in fish catch was less likely to occur in response to potential climate and land-use changes if a lake is located in a region with greater access to clean water. This finding suggests that adequate investments for water-quality protection and water-use efficiency can provide additional benefits to lake fisheries and food security.

Nature Communications

Oxygen adsorption and the magnetic susceptibility of ice at low temperatures

WHEN dealing with the magnetic susceptibility of tumour tissue 1 , we reported the magnetic susceptibility of ice at various temperatures from 273° K. down to 77° K. Since this publication, the authors have made many susceptibility measurements of ice, using the same equipment, and have obtained similar results, that is, a relatively large increase in diamagnetism below 150° K. Normal diamagnetism is not dependent on temperature, and hence further experiments were made of the magnetic susceptibility of ice at low temperatures in an attempt to determine some extraneous cause of the increased diamagnetism.

Nature

Magnetic susceptibility of tektites and some other glasses

The magnetic susceptibility at several magnetic field strengths of about thirty tektites from various localities have been measured. The susceptibility ranges from 2 × 10 −6 to about 7.9 × 10 −6 e.m.u./g. Tektites from a given locality have similar susceptibilities. The intensity of magnetization of all the tektites measured is zero or very small. For comparison, the same measurements have been made on about thirty obsidians. The magnetic susceptibilities cover approximately the same range, but the intensity of magnetization of the impurity was found to be much higher. By heating the obsidians to 1450°C the intensity of magnetization was reduced to zero. From the above data, it is shown that the tektites must have been heated well above 1400°C, and that essentially all the iron is in solution. On the other hand, the evidence shows that obsidians have not been heated much above this temperature, and that there is a significant amount of undissolved iron in the glass, probably as magnetite. Further, if tektites are extraterrestrial, they probably entered the earth's atmosphere as a glass.

Geochimica et Cosmochimica Acta

Absolute method of measuring magnetic susceptibility

An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved.

Review of Scientific Instruments