Snow Chemistry Across Antarctica

An updated compilation of published and new data of major-ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, the United Kingdom, the United States and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of Antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http:// www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized

A percutaneous technique for catheterization of the pulmonary artery without fluoroscopy.

The measurement of pressures in the chambers of the right side of the heart or pulmonary artery and withdrawal of blood samples for gas analysis pro-vide invaluable information for the study of patients with cardiac or pulmonary disease. If these patients are severely ill, it may be a risky procedure to move them to the catheterization laboratory, and a technique which allows these measurements to be made at the bedside, has been developed, and is described. TECHNIQUE A femoral or cubital vein is entered percutaneously with a Coumand needle (No. 160) and a catheter is inserted by the Seldinger technique (1953). Following insertion of the needle, a nylon cord (diameter 0 7 mm.) is passed into the vein. The needle is thereupon with-drawn and two teflon catheters are successively passed over the nylon cord guide, after enlarging the skin puncture with a small knife blade (Fig. 1). The vein may thus be entered with a catheter of larger diameter than the needle. The nylon cord and the inner teflon catheter are withdrawn after advancing the larger teflon catheter approximately 20 cm. into the vein. A polyethylene catheter (PE 50, outer diameter 1 0 mm. or PE 60 outer diameter 1-2 mm.) is then passed through the teflon catheter. The polyethylene catheter is connected to a pressure transducer and is advanced, the position of its tip being confirmed by observation of the pressure pulse on an oscilloscope or recorder. A special adaptor (Fig. 2) is used to flush the teflon catheter to keep its lumen free of blood. An outer catheter of teflon is preferred, because it is easy to pass through the tissues and can be sterilized, for use again, by boiling. The tips of the catheters must be adapted carefully, so that there are no sharp edges which might prevent the catheters passing easily through the skin, subcutaneous tissues, and vessel wall. This ma

Snow chemistry across Antarctica

Un updated compilation of published and new data of major ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, United Kingdom, the United States, and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http://www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized