Effects of long-term sample preservation on flow cytometric analysis of natural populations of pico-and nanophytoplankton

The effects of long-term preservation on flow cytometric parameters of natural oceanic populations of pico-and nanophytoplankton have been examined. Populations collected at oligotrophic subtropical and subarctic locations in the North Pacific were fixed with glutaraldehyde and frozen in liquid nitrogen, according to Vaulot et al. (1989). During six months’ storage, chlorophyll red fluorescence declined in all the groups examined, while forward light scatter was enhanced in Synechococcus and Prochlorococcus, and weakened in nanoeucaryotes. Cell loss was not significant except for Synechococcus. Caution is required when analyzing flow cytometric data of samples stored for more than a month.     

江西靖安东周墓出土玉器的玉质特征研究

为配合江西省文物考古研究所的出土文物研究,运用宝玉石学、岩石学和物理谱学的理论与资料,采用肉眼观察、宝石显微镜、红外吸收光谱（反射法）、激光拉曼光谱（散射法）、X射线衍射法和环境扫描电子显微镜等无损测试方法对江西靖安李洲坳东周墓的13件出土玉器样品进行了玉质特征鉴定。结果显示,有11件出土玉器样品为透闪石质软玉,2件出土玉器样品为粉砂岩类岩石。同时,还揭示了11件透闪石质软玉玉器的外观特征差异与其玉石成分和质地结构的关系。     

A practical numerical method for large strain liquefaction analysis of saturated soils

Accurate prediction of the liquefaction of saturated soils is based on strong coupling between the pore fluid phase and soil skeleton. A practical numerical method for large strain dynamic analysis of saturated soils is presented. The u–p formulation is used for the governing equations that describe the coupled problem in terms of soil skeleton displacement and excess pore pressure. A mixed finite element and finite difference scheme related to large strain analysis of saturated soils based on the updated Lagrangian method is given. The equilibrium equation of fluid-saturated soils is spatially discretized by the finite element method, whereas terms associated with excess pore pressure in the continuity equation are spatially discretized by the finite difference method. An effective cyclic elasto-plastic constitutive model is adopted to simulate the non-linear behavior of saturated soils under dynamic loading. Several numerical examples that include a saturated soil column and caisson-type quay wall are presented to verify the accuracy of the method and its usefulness and applicability to solutions of large strain liquefaction analysis of saturated soils in practical problems.     

Production of the Blood Pressure Lowing Peptides from Brown Alga （ Undaria pinnatifida ）

Brown alga （ Undaria pinnatifida） was treated with alginate lyase and hydrolyzed using 17 kinds of proteases and the inhibitory activity of the hydrolysates for the angiotensin-I-converting enzyme （ACE） was measured. Four hydrolysates with potent ACE-inhibitory activity were administered singly and orally to spontaneously hypertensive rats （SHRs）. The systolic blood pressure of SHRs decreases significantly after single oral administration of the brown alga hydrolysates by pro- tease S ＇ Amano＇ （from Bacillus stearothermophilus） at the concentration of 10 （mg protein） （kg body weight）^ - 1. In the 17 weeks of feeding experiment, 7-week-old SHRs were fed standard diet supplemented with the brown alga hydrolysates for 10 weeks. In SHRs fed 1.0 and 0.1% brown alga hydrolysates, elevating of systolic bloodpressure was significantly suppressed for 7 weeks. To elucidate the active components, the brown alga hydrolysates were fractionated by 1-butanol extraction and HPLC on a reverse-phase column. Seven kinds of ACE-inhibitory peptides were isolated and identified by amino acid composition analysis, sequence analysis, and LC-MS with the results Val-Tyr, Ile-Tyr, Ala-Trp, Phe-Tyr, Val-Trp, Ile-Trp, and Leu-Trp. Each peptide was determined to have an antihypertensive effect after a single oral administration in SHRs. The brown alga hydrolysates were also confirmed to decrease the blood pressure in humans.     

Spectrum of the relic neutrino background from past supernovae and cosmological models

It is greatly expected that the relic neutrino background from past supernovae will be detected by Superkamiokande (SK) which is now under construction. We calculate the spectrum and the event rate at SK systematically by using the results of simulations of a supernova explosion and reasonable supernova rates. We also investigate the effect of a cosmological constant, Λ, on the spectrum, since some recent cosmological observations strongly suggest the existence of Λ. We find following results. (1) The spectrum has a peak at about 3 MeV, which is much lower than that of previous estimates (6–10 MeV). (2) The event rate at SK in the range from 10 MeV to 50 MeV, where the relic neutrinos from past supernovae are dominant, is about 25h₅₀²(R_SN/0.1 yr⁻¹)(n_Gh₅₀⁻³/0.02 Mpc⁻³) events per year, where R_SN is the supernova rate in a galaxy, n_G is the number density of galaxies, and h₅₀ = H₀/(50 km/s Mpc), where H₀ is the Hubble constant. (3) The event rate is almost insensitive to Λ. The flux increases in the low energy side (< 10 MeV) with increasing Λ, but decreases in the high energy side (> 10 MeV) in models in which the integrated number of supernovae in one galaxy is fixed.     

http://www.sciencedirect.com/science/article/pii/S1674987112001533

The collision of a divergent ocean ridge may evolve into two end cases:in the continuity of ocean-floor subduction.or in the detachment of the subducted plate.The northern Patagonia active plate margin has the unique situation that in Cenozoic time it has been subjected to two divergent ridge collisions,each one representing one of the end members.The Neogene Antarctica-Nazca divergent ridge collision evolved as a continuous ocean-floor subduction system,promoting a magmatic hiatus at the arc axis,the obduction of part of the ridge ocean-floor in the fore-arc.and basaltic volcanism in the back-arc.In contrast,the Paleogene Farallon-Aluk divergent ridge collision evolved into a transform margin,with the detachment and sinking of the Aluk plate and the development of a large slab window.As in the previous case,this collision promoted a magmatic hiatus at the arc axis,but the tectono-magmatic scenario changed to postorogenic synextensional volcanism that spread to the former fore-arc（basalt,andesite,rhyolite） and former back-arc（bimodal ignimbrite flare-up,basalt）.Geochemistry of this slab window synextensional volcanism shows more MORB-like basalts towards the former fore-arc,and MORB-OIB-like basalts towards the former back-arc.Instead,an isolated undeformable crustal block in the former back-arc,with an "epeirogenic" response to the slab window and extensional regime,was covered by OIB-type basalts after uplift.Major elements show that slab window basalts reach TiCh values up to 3 wt%,as compared with the top value of 1.5 wt%of arc magmas.Besides,the MgO with respect to（FeO^t + Al₂O₃） ratio helps to distinguish slab window magma changes from the former fore-arc to the former back-arc and also with respect to the "epeirogenic" block.Higher contents of HFS elements such as Nb and Ta also help to distinguish this slab window from arc magmas and also,to distinguish slab window magma changes from the former fore-arc to the former back-arc and "epeirogenic" block settings.The isotope compositions of slab window magmatism show a disparate coeval array from MORB to crustal sources,interpreted as a consequence of the lack of protracted storage and homogenization due to the extensional setting.     

Experimental Study of Fe-Mg Exchange Reaction Between Orthopyroxene and Sapphirine and its Calibration as a Geothermometer

The exchange of Fe²⁺ and Mg²⁺ between orthopyroxene and sapphirine has been investigated at pressures 7-16 kbar and temperatures 850-1300°C using a piston cylinder apparatus for the synthetic and natural systems. This reaction is temperature-dependent and would be a good geothermometer. The equilibration temperature T is approximately expressed by the distribution coefficient as follows: T(°C)=1515/(ln K_D+0.943)-273.

This empirical equation was applied to some Antarctic granulites and associated rocks. The new orthopyroxene-sapphirine geothermometer gives consistent results with those estimated from the Fe-Mg orthopyroxene-garnet geothermometer.     

Some instabilities in the 3/1 and 2/1 resonances

In a very simple way, it is possible to show the existence of small regions of instability, inside the observed 3/1 and 2/1 Kirkwood Gap, by using the classical Laplace-Lagrange secular theory.