RELATIONSHIP BETWEEN UREA DECOMPOSITION AND CELL CLASSES OF RESERVOIR PHYTOPLANKTON IN THE NORTH HAN RIVER SYSTEM

The influence of natural phytoplankton cell classes upon the response of urea decomposition was investigated in four reservoirs in the North Han River System. The decomposition rate of urea was 0.3 to 29.4 μ mol urea・m⁻³・hr.⁻¹ in the light and 0.2 to 14.9 μ mol urea・m⁻³・hr.⁻¹ in the dark. Much higher decomposition rates were observed at the eutrophic stations in Lake Euiam. The urea decomposition in the smaller fraction (25 μm). No differences in the ratios of urea decomposition to chlorophyll-a or photosynthesis among three fractions were observed. This might be mainly due to the difference in the standing crop of phytoplankton. These trends were no different between sampling areas and reservoirs. The greater part of urea decomposition was the phase of CO₂ liberation rate into the water. Eight to 50% of the urea decomposition was incorporated into the particulate phase in the light, but this was much lower in the dark. The results of the present study indicate that urea in reservoirs decomposes by phytoplankton rather than bacteria and the phytoplankton would be competitive to bacteria.Article信州大学理学部付属諏訪臨湖実験所報告 7: 31-40(1991)departmental bulletin pape

Illuminating interfaces between phases of a U(1) x U(1) gauge theory

We study reflection and transmission of light at the interface between different phases of a U(1) x U(1) gauge theory. On each side of the interface, one can choose a basis so that one generator is free (allowing propagation of light), and the orthogonal one may be free, Higgsed, or confined. However, the basis on one side will in general be rotated relative to the basis on the other by some angle alpha. We calculate reflection and transmission coefficients for both polarizations of light and all 8 types of boundary, for arbitrary alpha. We find that an observer measuring the behavior of light beams at the boundary would be able to distinguish 4 different types of boundary, and we show how the remaining ambiguity arises from the principle of complementarity (indistinguishability of confined and Higgs phases) which leaves observables invariant under a global electric/magnetic duality transformation. We also explain the seemingly paradoxical behavior of Higgs/Higgs and confined/confined boundaries, and clarify some previous arguments that confinement must involve magnetic monopole condensation.Comment: RevTeX, 12 page

Sustainable composite super absorbents made from polysaccharides

Compared to traditional super absorbent polymers using raw materials from petrochemical industry, natural polymer absorbents are more favorable because they are sustainable and biodegradable. In this study, composite absorbents were developed by crosslinking carrageenan with sodium alginate using calcium chloride. Effect of composition on absorption was tested. Absorption was improved by increasing carrageenan content. The super absorbent exhibited the maximal swelling ratio of 13.1 g/g in 0.9% saline water in just 5 min. The maximal tensile strength was reached with a value of 12.8 MPa. Water contact angle revealed that carrageenan is more hydrophobic than sodium alginate. Presence of sulfate groups might be a key factor promoting absorption. The scanning electron microscopic images showed that the composite material had a structure with alginate arranged at the outside surface. These results demonstrate that a sustainable and biodegradable absorbent was successfully developed with a matrix of properties for potential application in diapers

Cooling Properties of Cloudy Bag Strange Stars

As the chiral symmetry is widely recognized as an important driver of the strong interaction dynamics, current strange stars models based on MIT bag models do not obey such symmetry. We investigate properties of bare strange stars using the Cloudy Bag Model, in which a pion cloud coupled to the quark-confining bag is introduced such that chiral symmetry is conserved. We find that in this model the decay of pions is a very efficient cooling way. In fact it can carry out most the thermal energy in a few milliseconds and directly convert them into 100MeV photons via pion decay. This may be a very efficient $\gamma$-ray burst mechanism. Furthermore, the cooling behavior may provide a possible way to distinguish a compact object between a neutron star, MIT strange star and Cloudy Bag strange star in observations.Comment: 23 pages, 14 figures, accepted by Astroparticle Physics, abstract appeared here has been shortene

New Higgs signals induced by mirror fermion mixing effects

We study the conditions under which flavor violation arises in scalar-fermion interactions, as a result of the mixing phenomena between the standard model and exotic fermions. Phenomenological consequences are discussed within the specific context of a left-right model where these additional fermions have mirror properties under the new SU(2)_R gauge group. Bounds on the parameters of the model are obtained from LFV processes; these results are then used to study the LFV Higgs decays (H --> tau l_j, l_j = e, mu), which reach branching ratios that could be detected at future colliders.Comment: 12 pages, 2 figures, ReVTex4, graphicx, to be published in Phys. Rev.

Electrochemical capacitance of a leaky nano-capacitor

We report a detailed theoretical investigation on electrochemical capacitance of a nanoscale capacitor where there is a DC coupling between the two conductors. For this ``leaky'' quantum capacitor, we have derived general analytic expressions of the linear and second order nonlinear electrochemical capacitance within a first principles quantum theory in the discrete potential approximation. Linear and nonlinear capacitance coefficients are also derived in a self-consistent manner without the latter approximation and the self-consistent analysis is suitable for numerical calculations. At linear order, the full quantum formula improves the semiclassical analysis in the tunneling regime. At nonlinear order which has not been studied before for leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge show interesting behavior. Our theory allows the investigation of crossover of capacitance from a full quantum to classical regimes as the distance between the two conductors is changed

Direct comparison of phase-space distributions of K- and K+ mesons in heavy-ion collisions at SIS energies - evidence for in-medium modifications of kaons ?

The ratio of K- to K+ meson yields has been measured in the systems RuRu at 1.69 A GeV, Ru+Zr at 1.69 A GeV, and Ni+Ni at 1.93 A GeV incident beam kinetic energy. The yield ratio is observed to vary across the measured phase space. Relativistic transport-model calculations indicate that the data are best understood if in-medium modifications of the kaons are taken into account.Comment: 14 pages including 3 figure

Systematics of pion emission in heavy ion collisions in the 1A GeV regime

Using the large acceptance apparatus FOPI, we study pion emission in the reactions (energies in GeV/nucleon are given in parentheses): 40Ca+40Ca (0.4, 0.6, 0.8, 1.0, 1.5, 1.93), 96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0, 1.5), 197Au+197Au (0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The observables include longitudinal and transverse rapidity distributions and stopping, polar anisotropies, pion multiplicities, transverse momentum spectra, ratios for positively and negatively charged pions of average transverse momenta and of yields, directed flow, elliptic flow. The data are compared to earlier data where possible and to transport model simulations.Comment: 56 pages,42 figures; to be published in Nuclear Physics