1,143 research outputs found
PROPAGATION OF ELECTROMAGNETIC WAVES IN SOME PUBLIC BUILDINGS IN CROSS RIVER STATES, NIGERIA
A Digital Community-Access (or Cable) Television (CATV) Analyzer with 24 channel spectrum 46 â 870MHz have been used to measured the received signal strength level, RxLev in four buildings (two office buildings and two residential buildings) in Calabar city at 519.25MHz. The results obtained indicated an average penetration loss of approximately 6dB with a standard deviation of 2dB. This is in accordance with several other studies done on this subject. In general, an increase has been found in the average signal strength when the receiver is moved upward in a building, the worst case situation being at ground floor
Theoretical infra-red, Raman, and Optical spectra of the B36N36 cage
The B36N36 fullerene-like cage structure was proposed as candidate structure
for the single-shell boron-nitride cages observed in electron-beam irradiation
experiment. We have performed all electron density functional calculations,
with large polarized Gaussian basis sets, on the B36N36 cage. We show that the
cage is energetically and vibrationally stable. The infra-red, Raman and
optical spectra are calculated. The predicted spectra, in combination with
experimentally measured spectra, will be useful in conclusive assignment of the
proposed B36N36 cage. The vertical and adiabatic ionization potentials as well
as static dipole polarizability are also reported.Comment: RevTex, 4 pages, 4 figures (TO appear in Physical Review A (Breif
Report)
Electronic structure of nanoscale iron oxide particles measured by scanning tunneling and photoelectron spectroscopies
We have investigated the electronic structure of nano-sized iron oxide by
scanning tunnelling microscopy (STM) and spectroscopy (STS) as well as by
photoelectron spectroscopy. Nano particles were produced by thermal treatment
of Ferritin molecules containing a self-assembled core of iron oxide. Depending
on the thermal treatment we were able to prepare different phases of iron oxide
nanoparticles resembling gamma-Fe2O3, alpha-Fe2O3, and a phase which apparently
contains both gamma-Fe2O3 and alpha-Fe2O3. Changes to the electronic structure
of these materials were studied under reducing conditions. We show that the
surface band gap of the electronic excitation spectrum can differ from that of
bulk material and is dominated by surface effects.Comment: REVTeX, 6 pages, 10 figures, submitted to PR
Agarose-based structured optical fibre
Biocompatible and resorbable optical fibres emerge as promising technologies for in vivo applications like imaging, light delivery for phototherapy and optogenetics, and localised drug-delivery, as well as for biochemical sensing, wherein the probe can be implanted and then completely absorbed by the organism. Biodegradable waveguides based on glasses, hydrogels, and silk have been reported, but most of these devices rely on complex fabrication procedures. In this sense, this paper proposes a novel structured optical fibre made of agarose, a transparent, edible material used in culture media and tissue engineering. The fibre is obtained by pouring food-grade agar into a mould with stacked rods, forming a solid core surrounded by air holes in which the refractive index and fibre geometry can be tailored by choosing the agarose solution composition and mould design, respectively. Besides exhibiting practical transmittance at 633ânm in relation to other hydrogel waveguides, the fibre is also validated for chemical sensing either by detecting volume changes due to agar swelling/dehydration or modulating the transmitted light by inserting fluids into the air holes. Therefore, the proposed agarose-based structured optical fibre is an easy-to-fabricate, versatile technology with possible applications for medical imaging and in vivo biochemical sensing101CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQCOORDENAĂĂO DE APERFEIĂOAMENTO DE PESSOAL DE NĂVEL SUPERIOR - CAPESFUNDAĂĂO DE AMPARO Ă PESQUISA DO ESTADO DE SĂO PAULO - FAPESPNĂŁo temNĂŁo tem2017/25666-
Effects of engaging communities in decision-making and action through traditional and religious leaders on vaccination coverage in Cross River State, Nigeria: a cluster-randomised control trial
BACKGROUND: Vaccination coverage levels fall short of the Global Vaccine and Action Plan 90% target in low- and middle- income countries (LMICs). Having identified traditional and religious leaders (TRLs) as potential public health change agents, this study aimed at assessing the effect of training them to support routine immunisation for the purpose of improving uptake of childhood vaccines in Cross River State, Nigeria. METHODS: A cluster-randomised controlled study was conducted between 2016 and 2019. Of the 18 Local Government Areas (LGA) in Cross River State, eight (four urban and four rural LGAs) were randomized into the intervention and control study arms. A multi-component intervention involving the training of traditional and religious leaders was implemented in the four intervention LGAs. Baseline, midline and endline surveys collected information on children aged 0-23 months. The effect of the intervention on outcomes including the proportion fully up-to-date with vaccination, timely vaccination for pentavalent and measles vaccines, and pentavalent 1-3 dropout rates were estimated using logistic regression models using random effects to account for the clustered data. RESULTS: A total of 2598 children at baseline, 2570 at midline, and 2550 at endline were included. The intervention was effective in increasing the proportion with at least one vaccine (OR 12.13 95% CI 6.03-24.41p<0.001). However, there was no evidence of an impact on the proportion of children up-to-date with vaccination (p = 0.69). It was effective in improving timeliness of Pentavalent 3 (OR 1.55; 95% CI: 1.14, 2.12; p = 0.005) and Measles (OR 2.81; 96% CI: 1.93-4.1; p<0.001) vaccination. The odds of completing Pentavalent vaccination increased (OR = 1.66 95% CI: 1.08,2.55). CONCLUSION: Informal training to enhance the traditional and religious leaders' knowledge of vaccination and their leadership role can empower them to be good influencers for childhood vaccination. They constitute untapped resources in the community to boost routine immunisation. Pan African Clinical Trial Registry (PACTR) PACTR202008784222254
Pathologies of the large-N limit for RP^{N-1}, CP^{N-1}, QP^{N-1} and mixed isovector/isotensor sigma-models
We compute the phase diagram in the N\to\infty limit for lattice RP^{N-1},
CP^{N-1} and QP^{N-1} sigma-models with the quartic action, and more generally
for mixed isovector/isotensor models. We show that the N=\infty limit exhibits
phase transitions that are forbidden for any finite N. We clarify the origin of
these pathologies by examining the exact solution of the one-dimensional model:
we find that there are complex zeros of the partition function that tend to the
real axis as N\to\infty. We conjecture the correct phase diagram for finite N
as a function of the spatial dimension d. Along the way, we prove some new
correlation inequalities for a class of N-component sigma-models, and we obtain
some new results concerning the complex zeros of confluent hypergeometric
functions.Comment: LaTeX, 88 pages, 33 figure
Plant structural changes due to herbivory: Do changes in Aceria-infested coconut fruits allow predatory mites to move under the perianth?
Being minute in size, eriophyoid mites can reach places that are small enough to be inaccessible to their predators. The coconut mite, Aceria guerreronis, is a typical example; it finds partial refuge under the perianth of the coconut fruit. However, some predators can move under the perianth of the coconut fruits and attack the coconut mite. In Sri Lanka, the phytoseiid mite Neoseiulus baraki, is the most common predatory mite found in association with the coconut mite. The cross-diameter of this predatory mite is c. 3 times larger than that of the coconut mite. Nevertheless, taking this predatorâs flat body and elongated idiosoma into account, it isârelative to many other phytoseiid mitesâbetter able to reach the narrow space under the perianth of infested coconut fruits. On uninfested coconut fruits, however, they are hardly ever observed under the perianth. Prompted by earlier work on the accessibility of tulip bulbs to another eriophyoid mite and its predators, we hypothesized that the structure of the coconut fruit perianth is changed in response to damage by eriophyoid mites and as a result predatory mites are better able to enter under the perianth of infested coconut fruits. This was tested in an experiment where we measured the gap between the rim of the perianth and the coconut fruit surface in three cultivars (âSri Lanka Tallâ, âSri Lanka Dwarf Greenâ and âSri Lanka Dwarf Green Ă Sri Lanka Tallâ hybrid) that are cultivated extensively in Sri Lanka. It was found that the perianth-fruit gap in uninfested coconut fruits was significantly different between cultivars: the cultivar âSri Lanka Dwarf Greenâ with its smaller and more elongated coconut fruits had a larger perianth-fruit gap. In the uninfested coconut fruits this gap was large enough for the coconut mite to creep under the perianth, yet too small for its predator N. baraki. However, when the coconut fruits were infested by coconut mites, the perianth-rim-fruit gap was not different among cultivars and had increased to such an extent that the space under the perianth became accessible to the predatory mites
Structure and magnetic properties of Fe-Ti-N films deposited by DC magnetron facing target sputtering
Using a facing target sputtering equipment, Fe-Ti-N films were deposited on water-cooled and heated substrates under different nitrogen flow ratios, R(N-2). The composition, microstructure, and magnetic properties of the films were investigated by Auger electron spectrosc (AES), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and a vibrating sample magnetometer (VSM). The films consist of alpha-Fe, TiNx, and Fe4N, where the volume fraction of these phases varies with R(N-2) and the substrate temperature during sputtering. The alpha-Fe(Ti) films with supersaturated nitrogen exhibit a larger M(s) than the Fe-Ti films. However, H-c first decreases and then increases with increasing R(N-2). This is ascribed to a distortion of the alpha-Fe lattice due to doping of Ti atoms and the compressive stress caused by the incorporation of sufficient nitrogen atoms
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