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

Vacuum-packaged micro fuel reformer for high thermal efficiency and low package temperature

MEMS 2008, Tucson, AZ, USA, January 13-17, 200

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

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

COMET 169P/NEAT(=2002 EX 12 ): THE PARENT BODY OF THE α-CAPRICORNID METEOROID STREAM

ABSTRACT The Jupiter-family comet 169P/NEAT (previously known as asteroid 2002 EX 12 ) has a dynamical association with the α-Capricornid meteoroid stream. In this paper, we present photometric observations of comet 169P/NEAT to further investigate the physical characters of its disintegration state related to the stream. The comet shows a point-like surface brightness profile limiting contamination due to coma emission to ∼4% at most, indicating no evidence of outgassing. An upper limit on the fraction of the surface that could be sublimating water ice of <10 −4 is obtained with an upper limit to the mass loss of ∼10 −2 kg s −1 . The effective radius of nucleus is found to be 2.3 ± 0.4 km. Red filter photometry yields a rotational period of 8.4096 ± 0.0012 hr, and the range of the amplitude 0.29 ± 0.02 mag is indicative of a moderately spherical shape having a projected axis ratio ∼1.3. The comet shows redder colors than the Sun, being compatible with other dead comet candidates. The calculated lost mass per revolution is ∼10 9 kg. If it has sustained this mass loss over the estimated 5000 yr age of the α-Capricornid meteoroid stream, the total mass loss from 169P/NEAT (∼10 13 kg) is consistent with the reported stream mass (∼ 10 13 -10 15 kg), suggesting that the stream is the product of steady disintegration of the parent at every return

Double In Situ Approach for the Preparation of Polymer Nanocomposite with Multi-functionality

A novel one-step synthetic route, the double in situ approach, is used to produce both TiO2nanoparticles and polymer (PET), and simultaneously forming a nanocomposite with multi-functionality. The method uses the release of water during esterification to hydrolyze titanium (IV) butoxide (Ti(OBu)4) forming nano-TiO2in the polymerization vessel. This new approach is of general significance in the preparation of polymer nanocomposites, and will lead to a new route in the synthesis of multi-functional polymer nanocomposites

Osteoblast-like cell responses to silicate ions released from 45S5-type bioactive glass and siloxane-doped vaterite

Silicate ions released from bioactive glasses and ceramics have been reported to stimulate osteogenic cell functions. Here, we evaluated osteoblast-like cell reactions to silicate ions released from two different types of materials, 45S5 bioactive glass (BG) and siloxane-doped vaterite (SiV), to investigate the influence of the ionic structure of silicate ions on osteoblast-like cell properties. BG and SiV powders were prepared by using melt-quenching and carbonation methods, respectively. Aminopropyltriethoxysilane was used as a siloxane source of SiV. MC3T3-E1 and SaOS-2 cells were cultured in media containing dissolved BG or SiV ions (10–50 ppm of Si). Cell proliferation (metabolic activity), differentiation (alkaline phosphatase activity) and mineralisation (Ca deposition) were examined. 29Si NMR spectra demonstrated that Q0,1 species and T0–3 species were released from BG and SiV, respectively. Proliferation and mineralisation of the two types of cells were influenced by silicate ions released from BG and SiV in a concentration-dependent manner. In particular, there were significant differences (P < 0.05) in the degree of proliferation and Ca deposition levels in SaOS-2 cells treated with dissolved BG and SiV ions. Furthermore, Ca deposition in SaOS-2 cells was influenced by both the presence of silicate ions and the duration of exposure of cells to them. The structure of silicate ions influenced the proliferation and mineralisation of SaOS-2 cells incubated for different time periods in culture media containing different Si concentrations. Understanding the effect of Si on bone cell behaviour will enable a design-led approach to further BG optimisation

Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

We address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2's electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different approximations within density functional theory and GW calculations. In particular, we propose very small (R < 0.5 nm) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod structure. We find that quantum confinement effects - as expected - generally lead to a widening of the energy gap. However, substitutional doping with boron or nitrogen is found to give rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For under coordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while for larger clusters and bulk structures donor states are introduced

Synthesis of titanate nanostructures using amorphous precursor material and their adsorption/photocatalytic properties

This paper reports on a new and swift hydrothermal chemical route to prepare titanate nanostructures (TNS) avoiding the use of crystalline TiO2 as starting material. The synthesis approach uses a commercial solution of TiCl3 as titanium source to prepare an amorphous precursor, circumventing the use of hazardous chemical compounds. The influence of the reaction temperature and dwell autoclave time on the structure and morphology of the synthesised materials was studied. Homogeneous titanate nanotubes with a high length/diameter aspect ratio were synthesised at 160^{\circ}C and 24 h. A band gap of 3.06\pm0.03 eV was determined for the TNS samples prepared in these experimental conditions. This value is red shifted by 0.14 eV compared to the band gap value usually reported for the TiO2 anatase. Moreover, such samples show better adsorption capacity and photocatalytic performance on the dye rhodamine 6G (R6G) photodegradation process than TiO2 nanoparticles. A 98% reduction of the R6G concentration was achieved after 45 minutes of irradiation of a 10 ppm dye aqueous solution and 1 g/L of TNS catalyst.Comment: 29 pages, 10 figures, accepted for publication in Journal of Materials Scienc