830 research outputs found
High Energy Tau Neutrinos
The intrinsic tau neutrino flux from cosmological and astrophysical sources
has usually been considered negligible in comparison to the electron and muon
neutrino fluxes. However, the inclusion of the tau neutrino component coming
from hadronic decay at the source can significantly modify the tau neutrino
spectrum expected at Earth. We report our results on the high energy tau
neutrino production and its implications for the observation of high energy
neutrino events.Comment: 3 pages, 3 figures. To appear in the Proceedings of TAUP2001,
September 8-12, 2001 - Gran Sasso Laboratory, Ital
Primordial black holes as a source of extremely high energy cosmic rays
The origin of observed extremely high energy cosmic rays remains an
astrophysical enigma. We show that a single evaporating primordial black hole
should produce 8.5*10^14 particles over a 10^20 eV threshold. This emission
results from direct production of fundamental constituants and from
hadronization of quarks and gluons. The induced flux on the Earth is studied as
a function of the local density of exploding black holes and compared with
experimental data. The discovery potential of future detectors is finally
reviewed.Comment: Accepted for publication in Astroparticle Physic
Degrees of Separation in the New Zealand Workforce: Evidence from Linked Employer-Employee Data
Recently published analysis of messages sent over the Microsoft instant-messaging network has shown that the old maxim of six degrees of separation is not far from the truth. The idea is that, on average, you are connected by no more than six links to all other 6.7 billion people on Earth. These links can be through blood, friendship or an acquaintance - you know someone who is friends with someone whose sister is married to someone ... and so on. Using Statistics NZ's Linked Employer-Employee Dataset (LEED), this maxim is tested on a network of wage and salary earners in New Zealand. The average shortest path between employees is derived, together with a range of measures, which describe characteristics of this unique view of the New Zealand labour market network
Search for Primordial Black Holes with SGARFACE
The Short GAmma Ray Front Air Cherenkov Experiment (SGARFACE) uses the
Whipple 10 m telescope to search for bursts of rays. SGARFACE is
sensitive to bursts with duration from a few ns to 20 s and with
-ray energy above 100 MeV. SGARFACE began operating in March 2003 and
has collected 2.2 million events during an exposure time of 2267 hours. A
search for bursts of rays from explosions of primordial black holes
(PBH) was carried out. A Hagedorn-type PBH explosion is predicted to be visible
within 60 pc of Earth. Background events were caused by cosmic rays and by
atmospheric phenomena and their rejection was accomplished to a large extent
using the time-resolved images. No unambiguous detection of bursts of
rays could be made as the remaining background events mimic the expected shape
and time development of bursts. Upper limits on the PBH explosion rate were
derived from the SGARFACE data and are compared to previous and future
experiments. We note that a future array of large wide-field air-Cherenkov
telescopes equipped with a SGARFACE-like trigger would be able to operate
background-free with a 20 to 30 times higher sensitivity for PBH explosions.Comment: 18 pages, 30 figures, accepted by Astroparticle Physics, corrected
author list and Section 2.
Southeast Asian refugees in New Zealand : language needs and provisions : a thesis completed in partial fulfilment of the requirements for the degree of Master of Philosophy in Education at Massey University
The resettlement of a particular group of non-Western refugees in New Zealand is studied from a sociolinguistic perspective. The language needs of the group are assessed together with the provisions that have been made to meet these needs. A review of pressures associated with refugee status and resettlement is provided. In addition, the provision of English as a second language (ESL) and the broader linguistic issues of bilingualism including language shift and language maintenance are discussed. The resettlement of over 7000 Vietnamese, Cambodian and Lao refugees in New Zealand since 1979 under a special Southeast Asian refugee resettlement programme has challenged the resources of government and voluntary agencies alike. Consequent ad hoc provisions of ESL have now become more-or-less permanent, bureaucratised and extended to cater for the ESL needs of other refugee and migrant groups. Nevertheless, many of the language programmes remain officially tied to the Southeast Asian resettlement scheme and are thus provisional and restricted in nature. The nature and extent of government and voluntary language provisions are assessed through an analysis of Department of Labour and Department of Education programmes. School, technical institute and home tutor provisions are surveyed, and supplemented by interviews and by questionnaires undertaken in local schools which have Southeast Asian refugee children. This information is set against on-arrival and post-arrival follow-up data derived from a sample of 230 case studies involving 785 individual refugees. These data cover the demographic, occupational, educational and linguistic characteristics of the Southeast Asian refugee sample. The study raises questions about the relationship between perceived and real language needs and between the language provisions which have been provided to meet these needs and the short- and longer-term effects of these provisions
Pernicious anaemia: a study of one hundred and seventy cases with special reference to complications
A resume of recent literature dealing with the
complications of pernicious anaemia is given.Tables have been compiled showing the sex, age,
haemoglobin percentage when first and last seen, complications
and treatment in 170 cases. Of these, males
numbered 84 and females 86. The average age on admission
was males 49, females 46.Notes of cases of special interest are included.The incidence and significance of complications is
discussed.Postero-lateral degeneration in some degree occurred
in 28 per cent of cases and to an advanced degree
in 13 per cent.Notes on duration, mortality and treatment are
given.The question is raised whether the red marrow in
the shafts of the long bones and the iron deposits in
the liver revert to normal during remissions. (Case 6).Attention is called to the occurrence of glossitis
occurring during remission of the anaemia. (Case 114).Three cases showed fibrillar tremors and muscular
wasting in addition to symptoms of postero-lateral
degeneration.Among the points of interest that emerge from this
study are the following.1. Since the introduction of liver therapy pregnancy
in cases of pernicious anaemia is no longer rare.
It occurred in 4 of the 86 female cases.
While pernicious anaemia is a serious complication
of pregnancy, pregnancy is not a serious complication
of well-treated pernicious anaemia.2. Cases of pernicious anaemia now live to have
numerous complications. Forty different conditions
were associated with the 170 cases studied, and some
complication was present in 70 per cent of the cases.
The most common and debilitating is postero-lateral
degeneration.3. The great majority of the associated conditions are
fortuitous but some of these, notably arteri.oscler.
osis, are important on account of their frequency,
and effect on expectation of life.4. Expectation of life has greatly increased:- Thus,
(a) Of the 170 cases seen in the course of ten
years 55 are still under observation and 10
are dead, but nothing is known of the others -
many had come from a distance.(b) Of the 170 cases admitted to hospital only 10
are known to have died and only one of these of
uncomplicated pernicious anaemia.(c) It is probable that many cases die of vascular
or nervous complications or may be killed by
motor cars.(d) It would appear that pernicious anaemia, so long
as well treated, is not now a very fatal disease.
It is the complications that kill, and among the
most serious of these is old age
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