The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and Redshifts (SuMIRe) project has been endorsed by Japanese community as one of the main future instruments of the Subaru ...8.2-meter telescope at Mauna Kea, Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution. Taking advantage of Subaru's wide field of view, which is further extended with the recently completed Wide Field Corrector, PFS will enable us to carry out multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A microlens is attached at each fiber entrance for F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. Fibers are accurately placed onto target positions by positioners, each of which consists of two stages of piezo-electric rotary motors, through iterations by using back-illuminated fiber position measurements with a wide-field metrology camera. Fibers then carry light to a set of four identical fast-Schmidt spectrographs with three color arms each: the wavelength ranges from 0.38 {\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving power of 3000. Before and during the era of extremely large telescopes, PFS will provide the unique capability of obtaining spectra of 2400 cosmological/astrophysical targets simultaneously with an 8-10 meter class telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil, Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and NAOJ/Subaru.
\(\mathrm{MnBi_2Te_4}\) has recently been established as an intrinsic antiferromagnetic (AFM) topological insulator and predicted to be an ideal platform to realize quantum anomalous Hall (QAH) ...insulator and axion insulator states. We performed comprehensive studies on the structure, nontrivial surface state and magnetotransport properties of this material. Our results reveal an intrinsic anomalous Hall effect arising from a non-collinear spin structure for the magnetic field parallel to the \(c\)-axis. We also observed remarkable negative magnetoresistance under arbitrary field orientation below and above the Neel temperature (T\(_N\)), providing clear evidence for strong spin fluctuation-driven spin scattering in both the AFM and paramagnetic states. Further, we found that the nontrivial surface state opens a large gap (~85 meV) even at temperatures far above T\(_N\) = 25K. These findings demonstrate that the bulk band structure of \(\mathrm{MnBi_2Te_4}\) is strongly coupled to the magnetic structure and that a net Berry curvature in momentum space can be created in a canted AFM state. In addition, our results imply that the gap opening in the surface states is intrinsic, likely caused by the strong spin fluctuations near the surface layers.
Abstract
Highly purified surface IgM-bearing B cells were isolated from T cell- and monocyte-depleted mononuclear cells by their ability to rosette with purified anti-IgM antibodies covalently linked ...to bovine red blood cells. Surface IgM-bearing B cells from both peripheral blood and tonsil were found to be excellent stimulator cells in unidirectional MLC reactions. In the majority of cases, the surface IgM-bearing B cells had a higher stimulatory capacity in the allogeneic MLC than non-T cells lacking surface IgM. Monocytes were also demonstrated to be good stimulators in the allogeneic MLC when a low number of cells was used. At high numbers, inhibition of tritiated thymidine uptake was observed, which appeared to be partly due to the release of prostaglandins and cold thymidine.
The population of non-T cells lacking surface IgM also showed stimulation that was especially strong in certain individuals. Because of the heterogeneity of this fraction, the primary cell involved could not be determined. It is of interest that this population was a more potent stimulator in the autologous MLC than was the surface IgM-bearing B cell fraction, although the latter was clearly active. Results from these studies also indicated that monocytes were relatively poor stimulators in the autologous MLC. Isolated Fab′ fragments of a rabbit anti-human Ia antiserum caused significant inhibition of both the allogeneic and autologous MLC.
The International HapMap Project Gibbs, Richard A; Belmont, John W; Hardenbol, Paul ...
Nature (London),
12/2003, Letnik:
426, Številka:
6968
Journal Article
PDF
