35,866 research outputs found
On the application of circular arrays in direction finding. Part I: Investigation into the estimation algorithms
Earlier extubation using axillary temperature as the endpoint for rewarming following hypothermic cardiopulmonary bypass
True Neutrality as a New Type of Flavour
A classification of leptonic currents with respect to C-operation requires
the separation of elementary particles into the two classes of vector C-even
and axial-vector C-odd character. Their nature has been created so that to each
type of lepton corresponds a kind of neutrino. Such pairs are united in
families of a different C-parity. Unlike the neutrino of a vector type, any
C-noninvariant Dirac neutrino must have his Majorana neutrino. They constitute
the purely neutrino families. We discuss the nature of a corresponding
mechanism responsible for the availability in all types of axial-vector
particles of a kind of flavour which distinguishes each of them from others by
a true charge characterized by a quantum number conserved at the interactions
between the C-odd fermion and the field of emission of the corresponding types
of gauge bosons. This regularity expresses the unidenticality of truly neutral
neutrino and antineutrino, confirming that an internal symmetry of a
C-noninvariant particle is described by an axial-vector space. Thereby, a true
flavour together with the earlier known lepton flavour predicts the existence
of leptonic strings and their birth in single and double beta decays as a unity
of flavour and gauge symmetry laws. Such a unified principle explains the
availability of a flavour symmetrical mode of neutrino oscillations.Comment: 19 pages, LaTex, Published version in IJT
Genetic diversity of Najdi sheep based on microsatellite analysis
The prime objective of this research was to measure the genetic polymorphism of main sheep breed of Saudi Arabia, Najdi. Randomly selected 49 blood samples were used to extract the DNA followed by polymerase chain reaction (PCR), using 19 microsatellite markers, which were used to investigate the genetic differentiation. Altogether, 173 alleles were identified ranging from 2 to 14, with the mean observed number alleles per locus of 9.11 ± 3.54. Apart from that, eight loci showed breed specific alleles which is critical in terms of conservation. The observed heterozygosity, expected heterozygosity, polymorphic information content and Shannon index, were 0.67 ± 0.19, 0.75 ± 0.14, 0.71 ± 0.16 and 1.69 ± 0.51, respectively. Therefore, considerable amount of genetic polymorphism has been shown by Najdi. Inbreeding coefficient of 0.13 exhibited moderate level of inbreeding prevailing, which may be partly due to the Wahlund effect (sub-population structure) at level of sampling. Nine out of the 19 loci encountered significant departure from Hardy Weinberg Equilibrium (p < 0.05). Based on the bottleneck analysis, there was no bottleneck effect in Najdi. This paper reports a comprehensive study on genetic diversity of Najdi, hence, it would be used for further advancement of this breed towards utilizing them sustainably.Keywords: Polymerase chain reaction (PCR), diversity, microsatellites, sheep, inbreedin
Acetylene-linked conjugated polymers for sacrificial photocatalytic hydrogen evolution from water
Conjugated organic polymers have shown potential as photocatalysts for hydrogen production by water splitting. Taking advantage of a high throughput screening workflow, two series of acetylene-linked co-polymers were prepared and studied for their potential as photocatalysts for sacrificial hydrogen production from water. It was found that a triethynylbenzene-based polymer with a dibenzo[b,d]thiophene sulfone linker (TE11) had the highest performance in terms of hydrogen evolution rate under visible illumination in the presence of a sacrificial hole-scavenger. Synthetically elaborating the triethynylbenzene linker in TE11 by changing the core and by introducing nitrogen, the resulting hydrogen evolution rate was further increased by a factor of nearly two
Phytochemical screening and antimicrobial efficacy of Alternanthera nodiflora extracts
The phytochemical constituents and antimicrobial activities of Alternanthera nodiflora extracts were analyzed. Plant sample was extracted using methanol and water. Qualitative phytochemical screening revealed the presence of alkaloids, carotenoid, flavonoids, terpenoids, cardiac glycosides, phenols and saponins while tannins were absent in both extracts. The antimicrobial potential of the extracts was tested against Staphylococcus aureus, Escherichia coli and Salmonella typhi, Candidaalbicans and Aspergillus niger. The Susceptibility patterns of the test organisms to varying concentrations (100mg/ml, 75mg/ml, 50mg/ml and 25mg/ml) of both extracts were determined by Kirby Bauer method. From this study, antimicrobial activity of the plant extracts was highest at 100mg/ml with Methanolic extract having more antimicrobial activity than aqueous extract. The extracts showed high activity against Candida albicans but no activity was observed against Aspergilus niger while the highest antibacterial activity of the extract was observed against Staphylococcus aureus.The higher antimicrobial activity in methanolic extract than aqueous extracts could be attributed to the degree of polarity of the extraction solvent.Key words: Alternanthera nodiflora, Phytochemicals, Antimicrobial activity, Extracts
Genetic variability of camel (Camelus dromedarius) populations in Saudi Arabia based on microsatellites analysis
The genetic diversity and population genetic structure of dromedary camels (Camelus dromedarius) are poorly documented in Saudi Arabia. The present study was conducted to address some of these genetics using four Saudi Arabian camel populations namely; Magaheem (MG), Maghateer (MJ), Sofr (SO) and Shual (SH). Genomic DNA was extracted from the hair roots of 160 camels, 40 individuals from each population. Sixteen microsatellite markers were used to genotype these 160 camels. Out of these 16 markers, only microsatellite VOLP67 did not produce any polymerase chain reaction (PCR) amplicons. There were 139 alleles generated by the 15 microsatellites loci with a mean of 9.27 alleles per locus. Four of the microsatellites loci studied in MG, eight in MJ and six in both SO and SH were found to be deviated from Hardy-Weinberg equilibrium. The fixation genetic indices (Fst) among the four populations were very low, ranging from 0.006 (between SH and SO) to 0.017 (between MG and MJ), indicating low population differentiation among the four Saudi camel populations. No significant heterozygote excess or bottleneck in most nearest past was detected in the four camel populations as indicated by sign, standardized differences and Wilcoxon tests, along with the normal L shaped distribution of mode-shift test. The present study showed that the microsatellite markers are powerful tools in breeding programs, although there is a need for applying more microsatellites in order to be able to discriminate fairly between camel populations of Saudi Arabia.Keywords: Camels, Camelus dromedarius, microsatellite markers, Saudi Arabia, genetic variabilit
Novel Tetrahedral Human Phantoms for Space Radiation Dose Assessment
Space radiation remains one of the primary hazards to spaceflight crews. The
unique nature of the intravehicular radiation spectrum makes prediction of
biological outcomes difficult, with computational simulation-based efforts
stymied by lack of computational resources or accurate modeling capabilities.
Recent advancements in both Monte Carlo simulations and computational human
phantom developments have allowed for complex radiation simulations and
dosimetric calculations to be performed for numerous applications. In this
work, advanced tetrahedral-type human phantoms were exposed to a simulated
spectrum of particles equivalent to a single days exposure in the International
Space Station in Low Earth Orbit. 3D Monte Carlo techniques were used to
produce and simulate the radiation spectra. Organ absorbed dose, average energy
deposition, and the whole-body integral dose was determined for a male and
female phantom. Results were then extrapolated for two long-term scenarios: a
6-9 month mission on the International Space Station and a 3-year mission to
Mars. The whole-body integral dose for the male and female models were found to
be 0.2985 +- 0.0002 mGy/day 0.3050 +- 0.0002 mGy/day, respectively, which is
within 10% of recorded dose values from the International Space Station. This
work presents a novel approach to assess absorbed dose from space-like
radiation fields using high-fidelity computational phantoms, highlighting the
utility of complex models for space radiation research.Comment: 10 pages, 3 figures, 2 table
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The development and sea trials of a subsea holographic camera for large volume in-situ recording of marine organisms
We describe the development, construction and sea testing of an underwater holographic camera (HoloCam) for in situ recording of marine organisms and particles in large volumes of sea water. HoloCam comprises a laser, power supply,
holographic recording optics and plate holders, a water-tight housing and a support frame. Added to this are control electronics such that the entire camera is remotely operable and controllable from ship or dock-side. Uniquely the camera can simultaneously record both in-line and off-axis holograms using a pulsed frequency doubled Nd-YAG laser. In-line holography is capable of producing images of organisms with a resolution of better than 10 Pm (at concentrations up to a few thousand per cubic centimetre at the smallest sizes). Off-axis holograms of aquatic systems of up to 50,000 cm3 volume, have been recorded. Following initial laboratory testing, the holo-camera was evaluated in an observation tank and ultimately was tested in Loch Etive, Scotland. In-line and off-axis holograms were recorded to a depth of 100 m. We will present results on the test dives and evaluation of the camera performance
Late Spontaneous Rupture in a Homografted Kidney: A Case Report
An unusual case of late spontaneous parenchymal perforation of an allogenic kidney transplant was successfully treated by nephrostomy drainage. © 1974, American Medical Association. All rights reserved
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