1,753 research outputs found
Recent Results from CARMA
The Combined Array for Research in Millimeter-wave Astronomy (CARMA) is a heterogeneous array of 23 telescopes designed to operate in the 1 cm, 3 mm, and 1 mm atmospheric windows. The array is a merger of the eight 3.5 m antennas from the Sunyaev-Zel’dovich Array, the nine 6.1 m antennas from the Berkeley-Illinois-Maryland array, and the six 10.4 m antennas from the Owens Valley Radio Observatory (OVRO). As a signature of Tom Phillips’ legacy, three of the CARMA antennas are from the original 3-element OVRO interferometer built under Tom’s leadership in the early 1980’s. Recent CARMA results are presented on the structure of circumstellar disks and the molecular gas distribution in M 51
Magnetic ground state of pyrochlore oxides close to metal-insulator boundary probed by muon spin rotation
Magnetism of ruthernium pyrochlore oxides A2Ru2O7 (A = Hg, Cd, Ca), whose
electronic properties within a localized ion picture are characterized by
non-degenerate t2g orbitals (Ru5+, 4d3) and thereby subject to geometrical
frustration, has been investigated by muon spin rotation/relaxation (muSR)
technique. The A cation (mostly divalent) was varied to examine the effect of
covalency (Hg > Cd > Ca) on their electronic property. In a sample with A = Hg
that exhibits a clear metal-insulator (MI) transition below >> 100 K (which is
associated with a weak structural transition), a nearly commensurate magnetic
order is observed to develop in accordance with the MI transition. Meanwhile,
in the case of A = Cd where the MI transition is suppressed to the level of
small anomaly in the resistivity, the local field distribution probed by muon
indicates emergence of a certain magnetic inhomogeneity below {\guillemotright}
30 K. Moreover, in Ca2Ru2O7 that remains metallic, we find a highly
inhomogeneous local magnetism below >>25 K that comes from randomly oriented Ru
moments and thus described as a "frozen spin liquid" state. The systematic
trend of increasing randomness and itinerant character with decreasing
covalency suggests close relationship between these two characters. As a
reference for the effect of orbital degeneracy and associated Jahn-Teller
instability, we examine a tetravalent ruthernium pyrochlore, Tl2Ru2O7 (Ru4+,
4d4), where the result of muSR indicates a non-magnetic ground state that is
consistent with the formation of the Haldane chains suggested by neutron
diffraction experiment.Comment: 12 pages, 13 figure
Expression of the apoptotic markers in normal breast epithelium, benign mammary dysplasia and in breast cancer
Apoptosis and proliferation are processes associated with the development and
progression of breast cancer. The sensitivity of tumour cells to the induction of
apoptosis depends on the balance between pro- and anti-apoptotic proteins.
The expression of Bak and Bcl-2 was examined using an immunohistochemical
method in 71 primary breast cancers. Furthermore, Bcl-2 and Bak were assessed
in the normal mammary gland as well as in benign mammary dysplasia adjacent
to breast cancer. Positive immunostaining for Bcl-2 was observed in 77.8% of
cases of normal breast epithelium (NBE), 93% of benign dysplasia without intraductal
proliferation (BBD) as well as in 94% of intraductal proliferative lesions of
the breast (BIPL). Expression of Bak was detected in 39% of cases of NBE, 45%
of BBD and in 67% of BIPL. In breast cancer Bcl-2 and Bak expression was found
in 83% and 70% of the cases studied, respectively. Increased Bcl-2 expression in
primary tumours significantly correlated with favourable prognostic factors, namely
pT1, G2 and lack of metastases to the regional lymph nodes (p < 0.01,
p < 0.03, p < 0.02, respectively). There were no relationships between Bak and
the clinicopathological features studied, but our results indicate changes in the
expression of Bak during breast cancer development and progression. It would
appear to be important to assess and compare pro- and anti-apoptotic proteins
between normal mammary gland, benign mammary dysplasia and the primary
tumours of breast cancer. This knowledge should be helpful in understanding
breast cancer development and progression
Equation of State for Parallel Rigid Spherocylinders
The pair distribution function of monodisperse rigid spherocylinders is
calculated by Shinomoto's method, which was originally proposed for hard
spheres. The equation of state is derived by two different routes: Shinomoto's
original route, in which a hard wall is introduced to estimate the pressure
exerted on it, and the virial route. The pressure from Shinomoto's original
route is valid only when the length-to-width ratio is less than or equal to
0.25 (i.e., when the spherocylinders are nearly spherical). The virial equation
of state is shown to agree very well with the results of numerical simulations
of spherocylinders with length-to-width ratio greater than or equal to 2
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