941 research outputs found
6D gauge-Higgs unification on T^2/Z_N with custodial symmetry
We investigate the gauge-Higgs unification models compactified on T^2/Z_N
that have the custodial symmetry. We select possible gauge groups, orbifolds
and representations of the matter fermions that are consistent with the
custodial symmetry, by means of the group theoretical analysis. The best
candidate we found is 6D SU(3)_C x U(4) gauge theory on T^2/Z_3 and the third
generation quarks are embedded into bulk fermions that are the symmetric
traceless rank-2 tensor of SO(6).Comment: 38 pages, 1 table, a reference adde
Self-compensating solenoid valve
A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug
Telomeres and Cellular Senescence in Metabolic and Endocrine Diseases
A number of observations suggest a close connection between telomere length and mortality and age-related disease, suggesting that telomere length is a useful marker of individual biological aging and the shortening of telomere length is causally related with the pathogenesis in age-related diseases. To date, the significance of telomere length in metabolic and endocrine diseases has also been clarified. It has been reported that obesity, type 2 diabetes mellitus (T2DM), NAFLD, and hypertension were associated with shortened telomere length. In endocrine diseases, polycystic ovary syndrome (PCOS), Cushing’s syndrome, and acromegaly were associated with shortened telomere length. In these conditions, an increased oxidative stress associated with the metabolic and hormonal abnormalities appears to play a pivotal role in the shortened telomere length. Recently, a large population-based study demonstrated that shortened telomeres at baseline were associated with an increased risk of metabolic diseases, suggesting that the shortened telomere itself plays a causal role for the onset or development of the metabolic diseases. In this chapter, the pathophysiological role of shortened telomere length in metabolic and endocrine diseases and the significance of cellular senescence are discussed
Airborne tracking sunphotometer apparatus and system
An airborne tracking Sun photometer apparatus has a rotatable dome. An azimuth drive motor is connected to rotate the dome. The dome has an equatorial slot. A cylindrical housing is pivotally mounted inside the dome at the equatorial slot. A photometer is mounted in the housing to move in the equatorial slot as the housing pivots. The photometer has an end facing from the slot with an optical flat transparent window. An elevation drive motor is connected to pivot the cylindrical housing. The rotatable dome is mounted in the bulkhead of an aircraft to extend from the interior of the aircraft. A Sun sensor causes the photometer to track the Sun automatically. Alternatively, the photometer may be oriented manually or by computer
Strong Turbulence in the Cool Cores of Galaxy Clusters: Can Tsunamis Solve the Cooling Flow Problem?
Based on high-resolution two-dimensional hydrodynamic simulations, we show
that the bulk gas motions in a cluster of galaxies, which are naturally
expected during the process of hierarchical structure formation of the
universe, have a serous impact on the core. We found that the bulk gas motions
represented by acoustic-gravity waves create local but strong turbulence, which
reproduces the complicated X-ray structures recently observed in cluster cores.
Moreover, if the wave amplitude is large enough, they can suppress the
radiative cooling of the cores. Contrary to the previous studies, the heating
is operated by the turbulence, not weak shocks. The turbulence could be
detected in near-future space X-ray missions such as ASTRO-E2.Comment: Movies are available at http://th.nao.ac.jp/tsunami/index.ht
High Metallicity of the X-Ray Gas up to the Virial Radius of a Binary Cluster of Galaxies: Evidence of Galactic Superwinds at High-Redshift
We present an analysis of a Suzaku observation of the link region between the
galaxy clusters A399 and A401. We obtained the metallicity of the intracluster
medium (ICM) up to the cluster virial radii for the first time. We determine
the metallicity where the virial radii of the two clusters cross each other (~2
Mpc away from their centers) and found that it is comparable to that in their
inner regions (~0.2 Zsun). It is unlikely that the uniformity of metallicity up
to the virial radii is due to mixing caused by a cluster collision. Since the
ram-pressure is too small to strip the interstellar medium of galaxies around
the virial radius of a cluster, the fairly high metallicity that we found there
indicates that the metals in the ICM are not transported from member galaxies
by ram-pressure stripping. Instead, the uniformity suggests that the
proto-cluster region was extensively polluted with metals by extremely powerful
outflows (superwinds) from galaxies before the clusters formed. We also
searched for the oxygen emission from the warm--hot intergalactic medium in
that region and obtained a strict upper limit of the hydrogen density
(nH<4.1x10^-5 cm^-3).Comment: Typo corrected. The published version is available on-line free of
charge by the end of 2008. http://pasj.asj.or.jp/v60/sp1/60s133/60s133.pd
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