489 research outputs found
Association of intestinal helminthic infection and nutritional status of primary school children in Gombe State, Nigeria
Background: Intestinal helminthic infections are among the commonest infections worldwide. It often affects the poorest communities and has similar geographic distribution with malnutrition. Intestinal helminthic infection contributes to undernutrition through subtle reduction in digestion and absorption of food, chronic inflammation and loss of nutrients. The objective of this study is to determine the prevalence of intestinal helminthic infection and its relationship with nutritional status of primary school children in Gombe, Gombe State, Nigeria.
Methodology: This was a cross sectional study of 350 pupils selected through multistage random sampling technique from 24 primary schools in Gombe, Gombe State, Nigeria from July 2018 to January 2019. Demographic information including age, gender, height, and weight were collected from each participant with a designed collection form. The data were analysed using SPSS version 24.0, and presented as frequency distribution and mean ± SD. The Chi-square test (with Odds ratio and 95% confidence interval) was used to test for association between prevalence of helminthiasis and factors such as gender, age group and school type. A p value of less than 0.05 was considered statistically significant at 95% confidence interval.
Results: The prevalence of intestinal helminthic infection was 23.7% (83/350). Eighty (96.4%) of the 83 infected pupils were in public schools while only 3 (3.6%) were in private schools (p<0.001). The prevalence of helminthiasis was significantly higher in underweight pupils (34%, OR=2.113, p=0.0065)) and significantly lower (5.4%, OR=0.1637, p=0.0037) in overweight pupils while the prevalence was not significantly associated with normal weight (p=0.5482) or obesity (p=1.000).
Conclusions: Intestinal helminthic infection is a public health problem in children with adverse significant relationship with nutritional status. Provision of toilet facilities in schools and periodic de-worming of pupils aimed at reducing loss of nutrients from intestinal helminthiasis are recommended
Association between hospital case volume and the use of bronchoscopy and esophagoscopy during head and neck cancer diagnostic evaluation
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102212/1/cncr28379.pd
A search for VHE counterparts of Galactic Fermi bright sources and MeV to TeV spectral characterization
Very high-energy (VHE; E>100 GeV) gamma-rays have been detected from a wide
range of astronomical objects, such as pulsar wind nebulae (PWNe), supernova
remnants (SNRs), giant molecular clouds, gamma-ray binaries, the Galactic
Center, active galactic nuclei (AGN), radio galaxies, starburst galaxies, and
possibly star-forming regions as well. At lower energies, observations using
the Large Area Telescope (LAT) onboard Fermi provide a rich set of data which
can be used to study the behavior of cosmic accelerators in the MeV to TeV
energy bands. In particular, the improved angular resolution of current
telescopes in both bands compared to previous instruments significantly reduces
source confusion and facilitates the identification of associated counterparts
at lower energies. In this paper, a comprehensive search for VHE gamma-ray
sources which are spatially coincident with Galactic Fermi/LAT bright sources
is performed, and the available MeV to TeV spectra of coincident sources are
compared. It is found that bright LAT GeV sources are correlated with TeV
sources, in contrast to previous studies using EGRET data. Moreover, a single
spectral component seems unable to describe the MeV to TeV spectra of many
coincident GeV/TeV sources. It has been suggested that gamma-ray pulsars may be
accompanied by VHE gamma-ray emitting nebulae, a hypothesis that can be tested
with VHE observations of these pulsars.Comment: Astronomy and Astrophysics, in press, 17 pages, 12 figures, 5 table
Search for a Correlation Between Very-High-Energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar
We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ \u3e 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits
Detection of Extended VHE Gamma Ray Emission from G106.3+2.7 with VERITAS
We report the detection of very-high-energy (VHE) gamma-ray emission from
supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with the
VERITAS atmospheric Cherenkov gamma-ray telescope resolve extended emission
overlapping the elongated radio SNR. The 7.3 sigma (pre-trials) detection has a
full angular extent of roughly 0.6deg by 0.4deg. Most notably, the centroid of
the VHE emission is centered near the peak of the coincident 12CO (J = 1-0)
emission, 0.4deg away from the pulsar PSR J2229+6114, situated at the northern
end of the SNR. Evidently the current-epoch particles from the pulsar wind
nebula are not participating in the gamma-ray production. The VHE energy
spectrum measured with VERITAS is well characterized by a power law dN/dE =
N_0(E/3 TeV)^{-G} with a differential index of G = 2.29 +/- 0.33stat +/-
0.30sys and a flux of N_0 = (1.15 +/- 0.27stat +/- 0.35sys)x 10^{-13} cm^{-2}
s^{-1} TeV^{-1}. The integral flux above 1 TeV corresponds to ~5 percent of the
steady Crab Nebula emission above the same energy. We describe the observations
and analysis of the object and briefly discuss the implications of the
detection in a multiwavelength context.Comment: 5 pages, 2 figure
Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics
Very-high energy (VHE) gamma quanta contribute only a minuscule fraction -
below one per million - to the flux of cosmic rays. Nevertheless, being neutral
particles they are currently the best "messengers" of processes from the
relativistic/ultra-relativistic Universe because they can be extrapolated back
to their origin. The window of VHE gamma rays was opened only in 1989 by the
Whipple collaboration, reporting the observation of TeV gamma rays from the
Crab nebula. After a slow start, this new field of research is now rapidly
expanding with the discovery of more than 150 VHE gamma-ray emitting sources.
Progress is intimately related with the steady improvement of detectors and
rapidly increasing computing power. We give an overview of the early attempts
before and around 1989 and the progress after the pioneering work of the
Whipple collaboration. The main focus of this article is on the development of
experimental techniques for Earth-bound gamma-ray detectors; consequently, more
emphasis is given to those experiments that made an initial breakthrough rather
than to the successors which often had and have a similar (sometimes even
higher) scientific output as the pioneering experiments. The considered energy
threshold is about 30 GeV. At lower energies, observations can presently only
be performed with balloon or satellite-borne detectors. Irrespective of the
stormy experimental progress, the success story could not have been called a
success story without a broad scientific output. Therefore we conclude this
article with a summary of the scientific rationales and main results achieved
over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic
rays, gamma rays and neutrinos: A survey of 100 years of research
Seesaw Mass Matrix Model of Quarks and Leptons with Flavor-Triplet Higgs Scalars
In a seesaw mass matrix model M_f = m_L M_F^{-1} m_R^\dagger with a universal
structure of m_L \propto m_R, as the origin of m_L (m_R) for quarks and eptons,
flavor-triplet Higgs scalars whose vacuum expectation values v_i are
proportional to the square roots of the charged lepton masses m_{ei}, i.e. v_i
\propto \sqrt{m_{ei}}, are assumed. Then, it is investigated whether such a
model can explain the observed neutrino masses and mixings (and also quark
masses and mixings) or not.Comment: version accepted by EPJ
Neutrino hierarchy from CP-blind observables with high density magnetized detectors
High density magnetized detectors are well suited to exploit the outstanding
purity and intensities of novel neutrino sources like Neutrino Factories and
Beta Beams. They can also provide independent measurements of leptonic mixing
parameters through the observation of atmospheric muon-neutrinos. In this
paper, we discuss the combination of these observables from a multi-kton iron
detector and a high energy Beta Beam; in particular, we demonstrate that even
with moderate detector granularities the neutrino mass hierarchy can be
determined for values greater than 4.Comment: 16 pages, 7 figures. Added a new section discussing systematic errors
(sec 5.2); sec.5.1 and 4 have been extended. Version to appear in EPJ
Study of the effect of neutrino oscillations on the supernova neutrino signal in the LVD detector
The LVD detector, located in the INFN Gran Sasso National Laboratory (Italy),
studies supernova neutrinos through the interactions with protons and carbon
nuclei in the liquid scintillator and interactions with the iron nuclei of the
support structure. We investigate the effect of neutrino oscillations in the
signal expected in the LVD detector. The MSW effect has been studied in detail
for neutrinos travelling through the collapsing star and the Earth. We show
that the expected number of events and their energy spectrum are sensitive to
the oscillation parameters, in particular to the mass hierarchy and the value
of , presently unknown. Finally we discuss the astrophysical
uncertainties, showing their importance and comparing it with the effect of
neutrino oscillations on the expected signal.Comment: Accepted for pubblication on Astroparticle Physics. 36 pages, 18
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