1,009 research outputs found
First hints of large scale structures in the ultra-high energy sky?
The result of the recent publication [M. Kachelriess and D. V. Semikoz
Astropart. Phys. 26, 10 (2006)] of a broad maximum around 25 degrees in the
two-point autocorrelation function of ultra-high energy cosmic ray arrival
directions has been intriguingly interpreted as the first imprint of the large
scale structures (LSS) of baryonic matter in the near universe. We analyze this
suggestion in light of the clustering properties expected from the PSCz
astronomical catalogue of LSS. The chance probability of the signal is
consistent within 2 sigma with the predictions based on the catalogue. No
evidence for a significant cross-correlation of the observed events with known
overdensities in the LSS is found, which may be due to the role of the galactic
and extragalactic magnetic fields, and is however consistent with the limited
statistics. The larger statistics to be collected by the Pierre Auger
Observatory is needed to answer definitely the question.Comment: 5 pages, 3 figures. Slightly enlarged discussion, clarifications
added, results unchanged. Matches published versio
Internal Audit, Sarbanes-Oxley And Athletic Departments: An Examination And Recommendations For Reform
During the past fifteen to twenty years the integrity of intercollegiate athletics has been seriously questioned as a result of an increased awareness of problems associated with institutional controls over athletic departments. Limited empirical evidence has been used in the debate regarding institutional controls pertaining to the athletic department. This paper provides empirical evidence regarding the use of the internal audit function as an institutional control. Our findings indicate that while the internal audits of athletic departments are adequate, the communication of these audit results is inadequate. We also discuss the applicability of recent legislation, Sarbanes-Oxley Act of 2002, to colleges and universities. Recommendations to enhance institutional controls regarding intercollegiate athletics are provided.
Lepton Numbers in the framework of Neutrino Mixing
In this short review we discuss the notion of lepton numbers. The strong
evidence in favor of neutrino oscillations obtained recently in the
Super-Kamiokande atmospheric neutrino experiment and in solar neutrino
experiments imply that the law of conservation of family lepton numbers L_e,
L_mu and L_tau is strongly violated. We consider the states of flavor neutrinos
nu_e, nu_mu and nu_tau and we discuss the evolution of these states in space
and time in the case of non-conservation of family lepton numbers due to the
mixing of light neutrinos. We discuss and compare different flavor neutrino
discovery experiments. We stress that experiments on the search for
nu_mu->nu_tau and nu_e->nu_tau oscillations demonstrated that the flavor
neutrino nu_tau is a new type of neutrino, different from nu_e and nu_mu. In
the case of neutrino mixing, the lepton number (only one) is connected with the
nature of massive neutrinos. Such conserved lepton number exist if massive
neutrinos are Dirac particles. We review possibilities to check in future
experiments whether the conserved lepton number exists.Comment: 20 page
Secondary Beam Monitors for the NuMI Facility at FNAL
The Neutrinos at the Main Injector (NuMI) facility is a conventional neutrino
beam which produces muon neutrinos by focusing a beam of mesons into a long
evacuated decay volume. We have built four arrays of ionization chambers to
monitor the position and intensity of the hadron and muon beams associated with
neutrino production at locations downstream of the decay volume. This article
describes the chambers' construction, calibration, and commissioning in the
beam.Comment: Accepted for publication in Nucl. Instr. Meth.
Chewing Through the Miocene: An Examination of the Feeding Musculature in the Ground Sloth Hapalops from South America (Mammalia: Pilosa)
Hapalops, a smaller-sized and early sloth of the Megatheroidea, appeared in the middle Miocene Santa Cruz formation of Argentina. This genus is part of the group from which later, larger megatheroids arose, i.e., Nothrotheriops and Megatherium. Many cranial characters support this idea; however Hapalops is not merely a smaller antecedent of the later forms. Specifically, Hapalops retains short anterior caniniform teeth, and a temporomandibular joint elevated above the cheek tooth row; a combination distinct among sloths. An elevated temporomandibular joint occurs in Bradypus, a tree sloth with anterior chisel-shaped teeth instead of caniniforms, and the tree sloth Choloepus, which is aligned with the megalonychids, has anterior caniniforms. Hapalops has an elongated zygomatic ascending process that is reminiscent of that in Bradypus; however, the Bradypus skull is extremely foreshortened while that of Hapalops is elongated, as in nothrotheres, but not deepened as in megatheres. Previous work identified many sloth cranial character complexes, and functional limitations on skull feature combinations. The unique Hapalops character patterns indicate a selective feeder with a mediolaterally oriented grinding stroke during mastication
The NuMI Neutrino Beam and Potential for an Off-Axis Experiment
The Neutrinos at the Main Injector (NuMI) facility at Fermilab is under
construction and due to begin operations in late 2004. NuMI will deliver an
intense beam of variable energy 2-20 GeV directed into the Earth at
58 mrad. Several aspects of the design are reviewed, and potential limitations
to the ultimate neutrino flux are described. In addition, potential
measurements of neutrino mixing properties are described.Comment: talk given at NuFact '02, Imperial College London, proceedings to
appear in J. Phys. G, revised to add a referenc
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