Twisted Alexander polynomials and surjectivity of a group homomorphism

If phi: G-->G' is a surjective homomorphism, we prove that the twisted Alexander polynomial of G is divisible by the twisted Alexander polynomial of G'. As an application, we show non-existence of surjective homomorphism between certain knot groups.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-51.abs.htm

CIRCULAR GEOMETRY AND THE SCHWARZIAN

Special Volume(2000), Part III (Geometry and Topology

Studies on sinter deposits in Misasa radioactive hot springs (2nd report)

Qualitative and quantitative analysis of sinter deposits in a distributing pipe used for seventeen years (Sample No.1) and adhere to bathtub wall for eleven years (Sample No.2 and Sample No.3) in Misasa radioactive hot springs were investigated. The results were as follows ; (1) The color of deposits of Sample No.1 and Sample No.2 was black and the color of deposits of Sample No.3 was white. The metal elements in these deposits were qualitative analysed by spectraspan plasma emission spectrophotometry (SPES) and by fluorescent X-ray spectrometry. Following elements were detected, in Sample No.1 : Na, Mg, Al, K, Ca, Mn, Fe, Cu, As, Sr, Ba, Mo, and Pb, in Sample No.2 : Na, Mg, Al, Si, K, Ca, Ti, Mn, Fe, Cu, Zn, As, Sr, Ba, Pb and Cl and in Sample No.3 : Na, Mg, Al, Si, K, Ca, Mn, Fe, Cu, Zn, As, Rb, Sr, Mo, Ba, S, and Cl, (2) The metal elements in these deposits were quantitative analysed by SPES, atomic absorption spectrophotometry and emission spectrophometry. Following elements were determined, in Sample No.1 ; Mn : 411.6, Fe : 65.7, Ba : 20.0, Ca : 11.9, Na : 5.7, Cu : 4.5, K : 4.2, Sr : 2.9, Zn : 2.6, Mg : 1.4, in Sample No.2 ; Mn : 248.2, Fe : 28.5, Ba : 15.6, Ca : 25.0, Mg : 10.5, Na : 9.3, Cu : 5.4, K : 4.9, Sr: 7.4, Zn : 3.3, and in Sample No.3 ; Ca : 275.2, Sr : 32.4, Mg: 12.4, Na: 18.7, K: 5.0, Mn: 1.7 and Fe: 0.6mg per gram. The main components of these deposits were manganese compounds (Sample No.1 and Sample No.2) and calcium compounds (Sample No.3). Qualitative and quantitative analysis of barium in sinter deposits of Misasa spa was done by authers for the first time. (3) Radioactivity in these deposits were observed by autoradiography. Among the radioactive elements, concentration of radium were 3.41×10(-8) Ci/g (Sample No.1), 4.70×10(-9) Ci/g (Sample No.2) anp 2.36×10(-11) Ci/g (Sample No.3), respectively

FREQUENT MONITORING OF WATER TEMPERATURE IN PEGAMETAN BAY, BALI: A PRELIMINARY ASSESSMENT TOWARDS MANAGEMENT OF MARINE AQUACULTURE DEVELOPMENT

Aquaculture currently share for nearly half of the world’s food fish consumption, and continue to be the fastest-growing animal food producing sector. The viability of aquaculture operation has greatly been affected by the characteristic of marine environment. Inventory and monitoring of marine environment are necessary and can be done through information technology implementation. Frequent monitoring of water temperature, for almost one year observation, at four aquaculture sites in Pegametan Bay and Research and Development Institute for Mariculture was investigated. Water temperature data were obtained by using logger and buoy systems. These data were contrasted against marine fish mortality. On the other hand, the suitability of species requirements with the thermal conditions was evaluated by comparing temperature range to the optimum and lethal temperature information available on marine fish species of aquaculture interest. This research could be beneficial for enhancing productivity of marine aquaculture operation in terms of possible impact of climate change. It was also possible to find the ideal temperature range for culturing fish species, taking into account the variability associated with large-scale phenomena