3,569 research outputs found
Collaborative Agreements: A ‘how to’ guide
Partnerships can be an extremely effective way to harness additional skills and resources and minimize costs. Collaboration allows scientists (and other partners) to access a broad range of expertise and fosters a multi-disciplinary approach, both of which are often required when tackling complex research issues. However, it may be difficult to make the most of collaborative agreements, since different partners may have different objectives and approaches and misunderstandings can occur.partnership, Collaboration, agreements, Research and Development/Tech Change/Emerging Technologies,
Double-Chooz: a search for Theta13
The Double-Chooz experiment goal is to search for a non-vanishing value of
the Theta13 neutrino mixing angle. This is the last step to accomplish prior
moving towards a new era of precision measurements in the lepton sector. The
current best constraint on the third mixing angle comes from the CHOOZ reactor
neutrino experiment (90% C.L., eV). Double-Chooz will explore the range of
from 0.2 to 0.03-0.02, within three years of data
taking. The improvement of the CHOOZ result requires an increase in the
statistics, a reduction of the systematic error below one percent, and a
careful control of the backgrounds. Therefore, Double-Chooz will use two
identical detectors, one at 150 m and another at 1.05 km distance from the
Chooz nuclear cores. In addition, we will to use the near detector as a ``state
of the art'' prototype to investigate the potential of neutrinos for monitoring
the civil nuclear power plants. The plan is to start operation with two
detectors in 2008, and to reach a sensitivity sin of 0.05
in 2009, and 0.03-0.02 in 2011.Comment: 3 pages, 1 figure, Proceedings of Nufact'04, July 26 - August 01
2004, Osak
Future Reactor Neutrino Oscillation Experiments at Krasnoyarsk
Recent studies of atmospheric neutrinos and the results from CHOOZ and
Palo-Verde experiment call for new and more sensitive searches for neutrino
oscillations at reactors. The main goal of the project considered here is to
look for very small mixing angle oscillations of electron neutrinos in the
atmospheric neutrino mass parameter region around \Delta m^2 ~3 10^-3 eV^2 and
to define the element U_{e3} of the neutrino mixing matrix (U_{e3}is the
contribution of the mass-3 state to the electron neutrino flavor state). The
practical goal of the project is to decrease, relative to the CHOOZ, the
statistic and systematic errors as much as possible. To achieve this we plan to
use two identical antineutrino detectors each with a ~50-ton liquid
scintillator target located at ~1100 m and ~250 m from the underground reactor
(~600 mwe). Much attention is given to the detector calibration and monitoring
procedures. As a first step we consider two much smaller pilot detectors each
of ~ a 3 ton target mass stationed at ~20 m and 35-60 m from the reactor. The
goals of this first stage are: (i) to accumulate necessary experience and (ii)
to investigate with electron neutrinos the LSND mass parameter region.Comment: LaTeX file, 4 pages and 4 ps figure
Cabibbo Haze in Lepton Mixing
Quark-lepton unification suggests Cabibbo-sized effects in lepton mixings,
which we call Cabibbo haze. We give simple examples and explore possible
Wolfenstein-like parametrizations of the MNSP matrix which incorporate leptonic
Cabibbo shifts. We find that the size of the CHOOZ angle is not always
correlated with the observability of CP violation.Comment: 10 page
Effects and influences on neutrino oscillations due to a thin density layer perturbation added to a matter density profile
In this paper, we show the effects on the transition probabilities for
neutrino oscillations due to a thin constant density layer perturbation added
to an arbitrary matter density profile. In the case of two neutrino flavors, we
calculate the effects both analytically and numerically, whereas in the case of
three neutrino flavors, we perform the studies purely numerically. As an
realistic example we consider the effects of the Earth's atmosphere when added
to the Earth's matter density profile on the neutrino oscillation transition
probabilities for atmospheric neutrinos.Comment: 9 pages, 6 figures, LaTeX. Final version to be published in Phys.
Lett.
Scenarios approach to the electromagnetic exposure. The case study of a train compartment
Previous studies identified the train compartment as the place where people can experience the highest exposure levels (still below the international guideline limits) to electromagnetic fields in the radiofrequency range. Here a possible scenario of a train compartment has been reproduced and characterized, both numerically and experimentally. A good agreement between the simulated electric field distributions and measurements has been found. Results indicate that the higher values of exposure in specific positions inside the train compartment depend on the number of active cell phones, the bad coverage condition, the cell orientation, and the presence of metallic walls. This study shows that the proposed approach, based on the scenarios characterization, may efficiently support the assessment of the individual electromagnetic exposure
Quark-Lepton Mass Matrices with Flavor Symmetry
The U(1) flavor symmetry explains the large mixing of neutrinos while it
leads to the unique texture for the quark mass matrices. It is remarked that
U(1) symmetric mass matrices have the phenomenological defects. In the quark
sector, the mixing is predicted to be large compared with the expected
value \l^4 at the GUT scale. In the lepton sector, U(1) charges, which give a
large mixing in the neutrino sector, also lead to the large one in the charged
lepton sector. In the viewpoint of the flavor symmetry, this is an unpleasant
feature because the neutrino mass hierarchy is determined only by unknown
coefficients of , and the near-maximal flavor mixing is not
guaranteed in the case of both large angle rotations. These defects disappear
by introducing additional discrete symmetries . The quark-lepton mass matrices are presented by taking account of
the recent data of atmospheric neutrinos and solar neutrinos.Comment: 19 pages, LaTex file, no figure
Effects of temperature on the biology of the northern shrimp, Pandalus borealis, in the Gulf of Maine
Length-frequency data collected from inshore and offshore locations in the Gulf of Maine in 1966-1968 indicated that ovigerous female northern shrimp (Pandalus borealis) first appeared offshore in August and September and migrated
inshore in the fall and winter. Once eggs hatched, surviving females returned offshore. Juveniles and males migrated offshore during their first two years of life. Sex transition occurred in both inshore and oll'shore waters, but most males changed sex offshore during their third and fourth years. Most shrimp changed sex and matured as females for the first time in their fourth year. Smaller females and females exposed to colder bottom temperatures spawned first. The incidence of egg parasitism peaked in January and was higher for shrimp exposed to warmer bottom temperatures. Accelerated growth at higher temperatures appeared to result in earlier or more rapid sex transition. Males and non-ovigerous females were observed to make diurnal vertical migrations, but were not found in near-
surface waters where the temperature exceeded 6°C. Ovigerous females fed more heavily on benthic molluscs in inshore waters in the winter, presumably because the egg masses they were carrying prevented them from migrating vertically at night.
Northern shrimp were more abundant in the southwestern region of the Gulf of Maine where bottom temperatures remain low throughout the year. Bottom trawl catch rates were highest in Jeffreys Basin where bottom temperatures were lower than at any other sampling location. Catch rates throughout the study area were inversely related to bottom temperature and reached a maximum at 3°C.
An increase of 40% in fecundity between 1973 and 1979 was associated with a decline of 2-3°C in April-July offshore bottom temperatures. Furthermore, a decrease in mean fecundity per 25 mm female between 1965 and 1970 was linearly related to reduced landings between 1969 and 1974. It is hypothesized that temperature-induced changes in fecundity and, possibly, in the extent of egg mortality
due to parasitism, may provide a mechanism which could partially account for changes in the size of the Gulf of Maine northern shrimp population during the last thirty years. (PDF file contains 28 pages.
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