242 research outputs found
What we have learned from the ALMA Long Baseline Campaigns
No full textI present mm/submm phase characteristics measured at the ALMA long baseline campaigns, and suggestions to a large aperture submillimeter telescope. All the measured spatial structure function (SSF) show that the phase fluctuation increases as a function of baseline length, with a power-law slope of ~0.6 up to around 1 km. In many cases, the slope becomes shallower (average of ~0.2-0.3) at baseline lengths longer than around 1 km, namely showing a turn-over in SSF, but in some rare cases, the slope keep the same from short baselines to long baselines. This characteristics affects the site selection of the single-dish telescopes that may correlate with ALMA. Furthermore, for a large aperture submillimeter telescope, short baseline phase characteristics affect its pointing, known as the anomalous refraction. I will also mention about this effect based on the ALMA Long Baseline Campaign data
Effects of carriers on transgene expression from plasmids containing a DNA sequence with high histone affinity
Full text linkThe intranuclear disposition of plasmid DNA is highly important for transgene expression. The effects of a left-handedly curved sequence with high histone affinity on transgene expression were examined in COS-7 cells with two kinds of carriers (Lipofectamine Plus and TransIT-LT1). Three plasmids containing the curved sequence at different positions were transfected. The transgene expression was affected by the position of the left-handedly curved sequence, and the sequence at appropriate locations enhanced the expression from plasmid DNAs. However, the position effects on the expression differed from those obtained by electroporation of the same plasmid DNAs in a naked form. In addition, the degree of expression enhancement seemed to depend on the carriers. These results suggest that the left-handedly curved sequence with high histone affinity could increase the transgene expression from a plasmid delivered with carriers
Boundary integral equation approach based on a polynomial expansion of the current distribution to reconstruct the current density profile in tokamak plasmas
Full text linkA new approach has been proposed to reconstruct the current density profile in tokamak plasmas. The boundary-only integral equation derived from the Grad–Shafranov equation, under the assumption of polynomial expansion of current density, will have no unknowns except for the polynomial expansion coefficients, once the magnetic flux and its derivative have been given along the plasma boundary with the aid of Kurihara's Cauchy-condition surface method based on magnetic sensor data. In addition to the discretized form of the equation, some constraints are taken into account: the total plasma current, zero-current along the plasma boundary and a scalar relationship derived from the MHD equilibrium to relate the current density to the magnetic flux. It is also assumed that the poloidal field, as a quantity closely related to the current density, can be measured at a certain number of points inside the plasma. The whole set of linear equations is solved using the singular value decomposition technique to determine the polynomial expansion coefficients. The validity of the present technique and the quality of the current density solution have been investigated through test calculations for some plasma configurations
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