1,675 research outputs found
Identification problems of muon and electron events in the Super-Kamiokande detector
In the measurement of atmospheric nu_e and nu_mu fluxes, the calculations of
the Super Kamiokande group for the distinction between muon-like and
electronlike events observed in the water Cerenkov detector have initially
assumed a misidentification probability of less than 1 % and later 2 % for the
sub-GeV range. In the multi-GeV range, they compared only the observed
behaviors of ring patterns of muon and electron events, and claimed a 3 %
mis-identification. However, the expressions and the calculation method do not
include the fluctuation properties due to the stochastic nature of the
processes which determine the expected number of photoelectrons (p.e.) produced
by muons and electrons. Our full Monte Carlo (MC) simulations including the
fluctuations of photoelectron production show that the total mis-identification
rate for electrons and muons should be larger than or equal to 20 % for sub-GeV
region. Even in the multi-GeV region we expect a mis-identification rate of
several % based on our MC simulations taking into account the ring patterns.
The mis-identified events are mostly of muonic origin.Comment: 17 pages, 12 figure
The Carnot Cycle for Small Systems: Irreversibility and the Cost of Operations
We employ the recently developed framework of the energetics of stochastic
processes (called `stochastic energetics'), to re-analyze the Carnot cycle in
detail, taking account of fluctuations, without taking the thermodynamic limit.
We find that both processes of connection to and disconnection from heat
baths and adiabatic processes that cause distortion of the energy distribution
are sources of inevitable irreversibility within the cycle. Also, the so-called
null-recurrence property of the cumulative efficiency of energy conversion over
many cycles and the irreversible property of isolated, purely mechanical
processes under external `macroscopic' operations are discussed in relation to
the impossibility of a perpetual machine, or Maxwell's demon.Comment: 11 pages with 3 figures. Resubmitted to Physical Review E. Many
paragraphs have been modifie
Effects of Gallium Doping in Garnet-Type Li7La3Zr2O12 Solid Electrolytes
Garnet-type Li7La3Zr2O12 (LLZrO) is a candidate solid electrolyte material that is now being intensively optimized for application in commercially competitive solid state Li+ ion batteries. In this study we investigate, by force-field-based simulations, the effects of Ga3+ doping in LLZrO. We confirm the stabilizing effect of Ga3+ on the cubic phase. We also determine that Ga3+ addition does not lead to any appreciable structural distortion. Li site connectivity is not significantly deteriorated by the Ga3+ addition (>90% connectivity retained up to x = 0.30 in Li7â3xGaxLa3Zr2O12). Interestingly, two compositional regions are predicted for bulk Li+ ion conductivity in the cubic phase: (i) a decreasing trend for 0 †x †0.10 and (ii) a relatively flat trend for 0.10 < x †0.30. This conductivity behavior is explained by combining analyses using percolation theory, van Hove space time correlation, the radial distribution function, and trajectory density
Vacuum-packaged micro fuel reformer for high thermal efficiency and low package temperature
MEMS 2008, Tucson, AZ, USA, January 13-17, 200
Molecular analyses identify hybridization-mediated nuclear evolution in newly discovered fungal hybrids
Adiabatic invariance with first integrals of motion
The construction of a microthermodynamic formalism for isolated systems based
on the concept of adiabatic invariance is an old but seldom appreciated effort
in the literature, dating back at least to P. Hertz [Ann. Phys. (Leipzig) 33,
225 (1910)]. An apparently independent extension of such formalism for systems
bearing additional first integrals of motion was recently proposed by Hans H.
Rugh [Phys. Rev. E 64, 055101 (2001)], establishing the concept of adiabatic
invariance even in such singular cases. After some remarks in connection with
the formalism pioneered by Hertz, it will be suggested that such an extension
can incidentally explain the success of a dynamical method for computing the
entropy of classical interacting fluids, at least in some potential
applications where the presence of additional first integrals cannot be
ignored.Comment: 2 pages, no figures (REVTeX 4
Mortality in a cohort of people living with HIV in rural Tanzania, accounting for unseen mortality among those lost to follow-up
Mortality assessment in cohorts with high lost to follow-up (LTFU) is challenging in settings with limited civil registration systems. We aimed to assess mortality in a clinical cohort (KIULARCO) of HIV-infected persons in rural Tanzania, accounting for unseen deaths among participants LTFU. We included adults enrolled in 2005-2015 and traced a non-random sample of those LTFU. We estimated mortality using Kaplan-Meier methods with: A) routinely-captured data; B) crudely incorporating tracing data; C) weighting using tracing data to crudely correct for unobserved deaths among participants LTFU; and D) weighting using tracing data accounting for participant characteristics. We investigated associated factors using proportional hazards models. Among 7460 adults, 646 (9%) died, 883 (12%) transferred clinics, and 2911 (39%) were LTFU. Of 2010 (69%) traced participants, 325 (16%) were found: 131 (40%) died and 130 (40%) transferred. Five-year mortality estimates were A) 13.1%; B) 16.2%; C) 36.8%; D) 35.1%. Higher mortality was associated with male sex, referral as hospital in-patient, living close to the clinic, lower body mass index, more advanced WHO stage, lower CD4 count, and less time since antiretroviral therapy initiation. Adjusting for unseen deaths among participants LTFU approximately doubled the five-year mortality estimates. Our approach is applicable to other cohorts adopting targeted tracing
Apollo asteroids (1566) Icarus and 2007 MK6: Icarus family members?
Although it is more complicated to search for near-Earth object (NEO)
families than main belt asteroid (MBA) families, since differential orbital
evolution within a NEO family can cause current orbital elements to drastically
differ from each other, we have found that Apollo asteroids (1566) Icarus and
the newly discovered 2007 MK6 are almost certainly related. Specifically, their
orbital evolutions show a similar profile, time shifted by only ~1000 yr, based
on our time-lag theory. The dynamical relationship between Icarus and 2007 MK6
along with a possible dust band, the Taurid-Perseid meteor swarm, implies the
first detection of an asteroidal NEO family, namely the "Icarus asteroid
family".Comment: 11 pages, 1 figure, to appear on Astrophysical Journal Letters
(journal info added
Nuts about Inquiry: Peanut Variation and Natural Selection
Despite the numerous advantages of using inquiry, many teachers do not use this method because of issues such as time constraints and increased workload. In addition, content such as evolution is particularly problematic to teach because of the perceived lack of hands-on activities and societal pressures. This inquiry activity is designed to help students understand an important component of evolution by natural selection. Through this activity students better understand natural variation within populations using peanuts. Students are encouraged to make links between population data, population diversity and evolution by using collected data to construct and interpret graphs. This article promotes National Science Education Content Standards A, C, and G, Iowa Teaching Standards 1, 2, 3, 4, and 5
Resistance of Mice to Infection with Friend Disease Virus After Subcutaneous Injection of Friend Virus and Friend Spleen-Cells
Swiss mice injected subcutaneously with suspensions of spleen cells or an extract of spleens from mice infected with Friend virus develop resistance to subsequent intravenous inoculation of Friend virus. A single injection of either Friend virus or Friend cells induces resistance. Immunized mice display resistance when challenged 6 months after immunization and survive for at least 20 weeks after infection. Neutralization tests indicate that serum, but not lymphoid cells of resistant animals, can neutralize Friend virus. In vitro neutralization tests indicate that residence of virus within the peritoneal cavity of immune mice for 1 h sharply reduces the infective titer of the virus
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