1,367 research outputs found
Chain Reduction for Binary and Zero-Suppressed Decision Diagrams
Chain reduction enables reduced ordered binary decision diagrams (BDDs) and
zero-suppressed binary decision diagrams (ZDDs) to each take advantage of the
others' ability to symbolically represent Boolean functions in compact form.
For any Boolean function, its chain-reduced ZDD (CZDD) representation will be
no larger than its ZDD representation, and at most twice the size of its BDD
representation. The chain-reduced BDD (CBDD) of a function will be no larger
than its BDD representation, and at most three times the size of its CZDD
representation. Extensions to the standard algorithms for operating on BDDs and
ZDDs enable them to operate on the chain-reduced versions. Experimental
evaluations on representative benchmarks for encoding word lists, solving
combinatorial problems, and operating on digital circuits indicate that chain
reduction can provide significant benefits in terms of both memory and
execution time
Fission of heavy hypernuclei with the Skyrme-Hartree-Fock approach
Fission-related phenomena of heavy hypernuclei are discussed with
the constraint Skyrme-Hartree-Fock+BCS (SHF+BCS) method, in which a similar
Skyrme-type interaction is employed also for the interaction between a
particle and a nucleon. Assuming that the particle
adiabatically follows the fission motion, we discuss the fission barrier height
of U. We find that the fission barrier height increases
slightly when the particle occupies the lowest level. In this case,
the particle is always attached to the heavier fission fragment. This
indicates that one may produce heavy neutron-rich hypernuclei through
fission, whose weak decay is helpful for the nuclear transmutation of
long-lived fission products. We also discuss cases where the particle
occupies a higher single-particle level.Comment: 20 pages, 18 figures, to be submitted to Nucl. Phys.
The time variation of dose rate artificially increased by the Fukushima nuclear crisis
A car-borne survey for dose rate in air was carried out in March and April 2011 along an expressway passing northwest of the Fukushima Dai-ichi Nuclear Power Station which released radionuclides starting after the Great East Japan Earthquake on March 11, 2011, and in an area closer to the Fukushima NPS which is known to have been strongly affected. Dose rates along the expressway, i.e. relatively far from the power station were higher after than before March 11, in some places by several orders of magnitude, implying that there were some additional releases from Fukushima NPS. The maximum dose rate in air within the high level contamination area was 36 μGy h−1, and the estimated maximum cumulative external dose for evacuees who came from Namie Town to evacuation sites (e.g. Fukushima, Koriyama and Nihonmatsu Cities) was 68 mSv. The evacuation is justified from the viewpoint of radiation protection
Power spectral density of the heterogeneous fracture compliance from scattered elastic wavefields
Lidar observation of ozone over Tsukuba (36 deg N, 140 deg E)
An ozone lidar system was installed at the National Institute for Environmental Studies (NIES) in Tsukuba, Japan in March 1988 and has been measuring vertical profiles of ozone (15 - 45 km) since September 1988. The lidar system consists of a XeCl (308 nm) excimer laser, its deuterium Raman shifter (339 nm), a XeF excimer laser (351 nm), a 2 m telescope, a receiving system and a data processing system. The precision of the derived ozone concentration is about 10 percent of an altitude of 40 km for a 4 hr observation. Temperature profiles (30 - 80 km) are also obtained from the Rayleigh scattering signals at 351 nm. Approximate 50 ozone measurements are carried out in a year and variations of vertical profiles of ozone such as seasonal variations and shorter-term variations are observed. Systematic errors due to aerosols had been negligible until the arrival of the stratospheric aerosols injected by the eruption of Mt. Pinatubo. Effects of the volcanic aerosols on ozone measurements depend on the differences between wavelengths used as the on- and off-resonance
Rapid Surface Oxidation as a Source of Surface Degradation Factor for Bi2Se3
Bi2Se3 is a topological insulator with metallic surface states residing in a
large bulk bandgap. It is believed that Bi2Se3 gets additional n-type doping
after exposure to atmosphere, thereby reducing the relative contribution of
surface states in total conductivity. In this letter, transport measurements on
Bi2Se3 nanoribbons provide additional evidence of such environmental doping
process. Systematic surface composition analyses by X-ray photoelectron
spectroscopy reveal fast formation and continuous growth of native oxide on
Bi2Se3 under ambient conditions. In addition to n-type doping at the surface,
such surface oxidation is likely the material origin of the degradation of
topological surface states. Appropriate surface passivation or encapsulation
may be required to probe topological surface states of Bi2Se3 by transport
measurements
Trends in incidence and mortality of tuberculosis in Japan : a population-based study, 1997–2016
Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (−6.2% and −5.4%, respectively) and women (−5.7% and −4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035
Low Energy Processes Associated with Spontaneously Broken N=2 Supersymmetry
We consider low energy processes described by the N=2 supercurrent on its
partially (to N=1) and spontaneously broken vacuum and the attendant
Nambu-Goldstone fermion (NGF), which the presence of the electric and magnetic
Fayet-Iliopoulos (FI) terms is responsible for. We show suppressions of
amplitudes decaying into the NGF as its momentum becomes small. In the
lagrangian realization (namely, the model of arXiv:hep-th/0409060) of the
conserved supercurrent, the NGF resides in the overall U(1), which is
nonetheless not decoupled, and interacts with the SU(N) sector through
nonderivative as well as derivative couplings. The low energy suppression is
instead accomplished by a cancellation between the annihilation diagram from
the Yukawa couplings and the contact four-Fermi terms. We give a complete form
of the supercurrent and the model is recast in more transparent notation.Comment: 20 pages, 6 figure
Characterisation and categorisation of the diversity in viscoelastic vibrational properties between 98 wood types
International audienceContext Increased knowledge on diversity in wood properties would have implications both for fundamental research and for promoting a diversification of uses as material. *Aims The objective is to contribute to overcoming the critical lack of data on the diversity of wood dynamic mechanical/viscoelastic vibrational properties, by testing lesser-known species and categorizing sources of variability. *Methods Air-dry axial specific dynamic modulus of elasticity (E'/γ) and damping coefficient (tanδ) were measured on a wide sampling (1792 specimens) of 98 wood types from 79 species. An experimental device and protocol was designed for conducting systematic (i.e. rapid and reproducible) characterizations. *Results Diversity at the specimens' level corroborates the "standard" relationship between tanδ and E'/γ, which is discussed in terms of orientation of wood elements and of chemical composition. Diversity at the species level is expressed on the basis of results for normal heartwood, with specific gravity (γ) ranging from 0.2 to 1.3. Axial E'/γ ranges from 9 to 32 GPa and tanδ from 4×10-3 to 19×10-3. Properties distribution follows a continuum, but with group characteristics. The lowest values of tanδ are only found in certain tropical hardwoods. Results can also suggest alternative species for musical instruments making
- …