1,554 research outputs found
Neutrino Decay and Atmospheric Neutrinos
We reconsider neutrino decay as an explanation for atmospheric neutrino
observations. We show that if the mass-difference relevant to the two mixed
states \nu_\mu and \nu_\tau is very small (< 10^{-4} eV^2), then a very good
fit to the observations can be obtained with decay of a component of \nu_\mu to
a sterile neutrino and a Majoron. We discuss how the K2K and MINOS
long-baseline experiments can distinguish the decay and oscillation scenarios.Comment: 9 pages, Revtex, uses epsf.sty, 3 postscript figures. Additions and
corrections to references, minor changes in the text and to some number
A Minimal Object Oriented Real-Time Operating System in C++
Most embedded software is currently developed using the C
programming language, even though its low level of abstrac-
tion requires a lot of effort to the programmer. The C++
language is a better choice because: it raises the level of
abstraction; it is strongly typed, so it prevents many com-
mon programming mistakes; it can be made as efficient as C
through fine-grained customisation of memory mechanisms;
it can be easily adapted to domain-specific needs. In ad-
dition, recent compilers have grown in maturity and per-
formance, and the new standard considerably improves the
language by introducing new concepts and an easier syntax.
In this paper we present ADOK, a minimal Real-Time Op-
erating System entirely written in C++ with the exception
of a few lines of assembler code. It directly offers a C++
interface to the developer, and it provides a flexible schedul-
ing framework which allows the developer to customise the
scheduling to its needs. In particular, we implement a two-
level scheduler based on Earliest Deadline First, the Stack
Resource Policy protocol for sharing resources and support
for mode changes. We demonstrate through examples and
a small case-study that ADOK can substantially improve
productivity without sacrificing on performance
Online regenerator placement.
Connections between nodes in optical networks are realized by lightpaths. Due to the decay of the signal, a regenerator has to be placed on every lightpath after at most d hops, for some given positive integer d. A regenerator can serve only one lightpath. The placement of regenerators has become an active area of research during recent years, and various optimization problems have been studied. The first such problem is the Regeneration Location Problem (Rlp), where the goal is to place the regenerators so as to minimize the total number of nodes containing them. We consider two extreme cases of online Rlp regarding the value of d and the number k of regenerators that can be used in any single node. (1) d is arbitrary and k unbounded. In this case a feasible solution always exists. We show an O(log|X| ·logd)-competitive randomized algorithm for any network topology, where X is the set of paths of length d. The algorithm can be made deterministic in some cases. We show a deterministic lower bound of W([(log(|E|/d) ·logd)/(log(log(|E|/d) ·logd))])log(Ed)logdlog(log(Ed)logd) , where E is the edge set. (2) d = 2 and k = 1. In this case there is not necessarily a solution for a given input. We distinguish between feasible inputs (for which there is a solution) and infeasible ones. In the latter case, the objective is to satisfy the maximum number of lightpaths. For a path topology we show a lower bound of Öl/2l2 for the competitive ratio (where l is the number of internal nodes of the longest lightpath) on infeasible inputs, and a tight bound of 3 for the competitive ratio on feasible inputs
Determining the sign of at long baseline neutrino experiments
Recently it is advocated that high intensity and low energy neutrino beams should be built to probe the mixing angle to
a level of a few parts in . Experiments using such beams will have better
signal to background ratio in searches for oscillations. We
propose that such experiments can also determine the sign of even
if the beam consists of {\it neutrinos} only. By measuring the transitions in two different energy ranges, the effects due to
propagation of neutrinos through earth's crust can be isolated and the sign of
can be determined. If the sensitivity of an experiment to
is , then the same experiment is automatically sensitive to matter
effects and the sign of for values of .Comment: Title changed and paper rewritten. 4 pages, 1 figure, revte
Extreme Galactic-Winds and Starburst in IR Mergers and IR QSOs
We report -as a part of a long-term study of mergers and IR QSOs- detailed
spectroscopic evidences for outflow (OF) and/or Wolf Rayet features in: (i) low
velocity OF in the ongoing mergers NGC 4038/39 and IRAS 23128-5919; (ii)
extreme velocity OF (EVOF) in the QSOs IRAS 01003-2238 and IRAS 13218+0552;
(iii) OF and EVOF in a complete sample of ultra-luminous IR galaxies/QSOs ("The
IRAS 1 Jy MKO-KPNO Survey", of 118 objects). We found EVOF in IRAS 11119+3257,
14394+5332, 15130+1958 and 15462-0450. The OF components detected in these
objects were mainly associated to starburst processes: i.e., to galactic-winds
generated in multiple type II SN explosions and massive stars. The EVOF were
detected in objects with strong starburst plus obscured IR QSOs; which suggest
that interaction of both processes could generate EVOF. In addition, we analyze
the presence of Wolf Rayet features in the large sample of Bright PG-QSOs
(Boroson and Green 1992), and nearby mergers and galactic-wind galaxies. We
found clear WR features in the Fe II QSOs (type I): PG 1244+026, 1444+407,
1448+273, 1535+547; and in the IR merger Arp 220. HST archive images of IR+BAL
QSOs show in practically all of these objects "arc or shell" features probably
associated to galactic-winds (i.e., to multiple type II SN explosions) and/or
merger processes. Finally, we discuss the presence of extreme starburst and
galactic wind as a possible evolutive link between IR merger and IR QSOs; where
the relation between mergers and extreme starburst (with powerful
galactic-winds) plays in important role, in the evolution of galaxies.Comment: 14 pages, 6 figure
Industrial-scale wind energy in Italian southern Apennine: territorio grabbing, value extraction and democracy
This paper analyses the penetration of industrial-scale wind energy in the south Italy provinces of Benevento, Avellino, Foggia and Potenza, which host 43 per cent of national installed capacity. Such a process has induced transformations affecting (i) historical contextualised socio-ecological patterns as a consequence of their inclusion into value extraction chains and (ii) substantive democratic dynamics at the local level. The underlying theoretical framework interprets the green economy or green capitalism as a transformation of capitalism mode of regulation in accordance with ecological modernisation theories. More precisely, it fits into the political ecology debate around extractivism, primitive accumulation, land grabbing and environmentality. The paper develops by first giving an account of the investment penetration, then describing extractive mechanisms in terms of practices and actors. The last two sections explore effects of such processes on territorial democracy and propose the concept of ‘territorio’ grabbing as an analytical innovation
The emission spectrum of the strong Fe II emitter BAL Seyfert 1 galaxy IRAS 07598+6508
The narrow-line Seyfert 1 galaxy IRAS 07598+6508 is known to be a stong Fe II
emitter. The analysis of several high S/N ratio spectra shows that its spectrum
is dominated by a relatively narrow "broad line" region (1 780 km s
FWHM) emitting not only Fe II, but also Ti II and Cr II lines. Although we were
unable to find a completely satisfactory physical model, we got the best
agreement with the observations with collisional rather than radiative models,
with a high density (n=10 cm), a high column density
(N=10 cm) and a microturbulence of 100 km s. This
BLR is qualitatively similar to the one observed in I Zw 1. We have not found
traces in IRAS 07598+6508 of the narrow line regions found in I Zw 1.Comment: 15 pages, 4 figures, accepted by A&
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