Neutrino fluence after r-process freeze-out and abundances of Te isotopes in presolar diamonds

Using the data of Richter et al. (1998) on Te isotopes in diamond grains from a meteorite, we derive bounds on the neutrino fluence and the decay timescale of the neutrino flux relevant for the supernova r-process. Our new bound on the neutrino fluence F after freeze-out of the r-process peak at mass number A = 130 is more stringent than the previous bound F < 0.045 (in units of 10**37 erg/cm**2) of Qian et al. (1997) and Haxton et al. (1997) if the neutrino flux decays on a timescale tau > 0.65 s. In particular, it requires that a fluence of F = 0.031 be provided by a neutrino flux with tau < 0.84 s. Such a fluence may be responsible for the production of the solar r-process abundances at A = 124-126 (Qian et al. 1997; Haxton et al. 1997). Our results are based on the assumption that only the stable nuclei implanted into the diamonds are retained while the radioactive ones are lost from the diamonds upon decay after implantation (Ott 1996). We consider that the nanodiamonds are condensed in an environment with C/O > 1 in the expanding supernova debris or from the exterior H envelope. The implantation of nuclei would have occurred 10**4-10**6 s after r-process freeze-out. This time interval may be marginally sufficient to permit adequate cooling upon expansion for the formation of diamond grains. The mechanisms of preferential retention/loss of the implanted nuclei are not well understood.Comment: AASTeX, 11 pages, 3 Postscript figure

Measurement of charm and bottom production in p+p collisions at s\sqrt{s} = 200 GeV at RHIC-PHENIX

RHIC-PHENIX has observed a large suppression pattern and azimuthal anisotropy of non-photonic electron at mid-rapidity ($\mid\eta\mid<0.35$) in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV. To understand these results and the interaction of heavy quarks in the hot and dense medium, experimental determination of production ratio of charm over bottom is one of the most important topics, since the behavior of bottom may differ from charm in the medium. We measured the ratio of charm over bottom and total cross section of bottom via partial reconstruction of D$^0$$\to$e$^+$ K$^-$ $\nu_e$ decay in p+p collisions at $\sqrt{s} = 200$ GeV. Total cross sections of charm and bottom were also measured via di-electron continuum in p+p collisions at $\sqrt{s} = 200$ GeV.Comment: 4pages, 4figures,coferenc

Wilson chains are not thermal reservoirs

Wilson chains, based on a logarithmic discretization of a continuous spectrum, are widely used to model an electronic (or bosonic) bath for Kondo spins and other quantum impurities within the numerical renormalization group method and other numerical approaches. In this short note we point out that Wilson chains can not serve as thermal reservoirs as their temperature changes by a number of order Delta E when a finite amount of energy Delta E is added. This proves that for a large class of non-equilibrium problems they cannot be used to predict the long-time behavior.Comment: 2 page

Redshifted emission lines and radiative recombination continuum from the Wolf-Rayet binary theta Muscae: evidence for a triplet system?

We present XMM-Newton observations of the WC binary Theta Muscae (WR 48), the second brightest Wolf-Rayet binary in optical wavelengths. The system consists of a short-period (19.1375 days) WC5/WC6 + O6/O7V binary and possibly has an additional O supergiant companion (O9.5/B0Iab) which is optically identified at a separation of ~46 mas. Strong emission lines from highly ionized ions of C, O, Ne, Mg, Si, S, Ar, Ca and Fe are detected. The spectra are fitted by a multi-temperature thin-thermal plasma model with an interstellar absorption N_H = 2--3*10**21 cm**-2. Lack of nitrogen line indicates that the abundance of carbon is at least an order of magnitude larger than that of nitrogen. A Doppler shift of ~630 km/s is detected for the OVIII line, while similar shifts are obtained from the other lines. The reddening strongly suggests that the emission lines originated from the wind-wind shock zone, where the average velocity is ~600 km/s. The red-shift motion is inconsistent with a scenario in which the X-rays originate from the wind-wind collision zone in the short-period binary, and would be evidence supporting the widely separated O supergiant as a companion. This may make up the collision zone be lying behind the short-period binary. In addition to the emission lines, we also detected the RRC (radiative recombination continuum) structure from carbon around 0.49 keV. This implies the existence of additional cooler plasma.Comment: 6 pages, 4 figures, accepted to A&

Sustainability Research of the Secure Wireless Communication System with Channel Reservation

The paper presents the research of the stability of the system with redundancy of communication channels. For this, two prototypes have been developed that are built (1) according to the classical circuit-switched scheme and (2) with aggregation of several virtual channels. Prototyping, installation on various vehicles and measurements of the stability of the entire system as a whole were carried out. The paper also presents structural diagrams, hardware, and a list of problems and difficulties that the authors encountered during the practical implementation and implementation of these systems. In the future, it is planned to expand the study of these systems when working with high-level channel virtualization and the search for methods to accelerate its work

Magnitude and variation of traffic air pollution as measured by CO in the City of Addis Ababa, Ethiopia

Background: Air pollution level in Addis Ababa is presumed to be high due to the prevalence of old vehicles and substandard road infrastructures. This study assessed CO concentration as a measure of traffic air pollution.Materials and methods: a total of 80 road side and 24 on-road daily traffic air samples during wet and dry seasons of 2007 and 2008, respectively, were taken using CO data logger. A structured checklist was used to document related data. Downloaded data from the CO sampler was used to generate summary statistics and data presentations. Data quality of CO measurement was ensured using calibration checks.Results: The mean for 15 minutes CO concentration was 2.1 ppm (GM=1.3) and 2.8 ppm (GM=2.2) for wet and dry seasons, respectively. The concentrations from season to season varied statistically. The CO temporal and spatial profiles among the two seasons were similar. The overall mean on-road CO concentration was 5.4 ppm (GM=5.3). Fifteen percent of roadside samples and all on-road samples exhibited more than 50% of the 8-hr CO WHO guideline.. Daily CO maxima were observed in early mornings and late afternoons.Conclusions: The consistency in spatial and temporal profiles and the variation on both on-road and road side traffic lines imply that vehicles are the main source of traffic air pollution. There is a concern that the CO 8-hr World Health Organization guideline might be exceeded in future