369 research outputs found
EFFECTS OF SUBSTITUTION OF FAT WITH MELON SEED MEAL ON QUALITY CHARACTERISTICS OF PORK SAUSAGES
A study was conducted in which melon seed meal (MSM) replaced fat at 0, 33, 66, and 100% levels in four batches of pork sausages. The chemical and storage properties, cooking weight losses, and sensory properties, of the sausages were determined in the meat processing laboratory. The results showed that MSM increased both ash and crude protein contents. The highest ether extract (36%) was obtained for batch 1 (control) while the lowest value (25.50%) was recorded for batch 4. The values obtained for refrigeration weight losses increased with increase in MSM while the results for dry matter were statistically insignificant. Batch 3 had the highest cooking weight loss of 0.83% whilebatch one had the lowest value of 0.30%. The values obtained for sensory properties increased with increase in the level of MSM up to 66%. It was concluded that pork back fat can be replaced with MSM in pork sausage without adverse effect on processing yield
COMPARATIVE EFFECTS OF EGG YOLKS FROM DIFFERENT POULTRY BREEDS ON VIABILITY OF REFRIGERATED SPERMATOZOA FROM WEST AFRICAN DWARF BUCKS
Egg yolk from avian species is used as a common component of most semen extenders because of its wide availability, beneficial effect on sperm viability and protective effect on acrosome against temperature-related damage during semen preservation. This study was carried out to determine the comparative effects of egg yolks from different poultry breeds on viability of refrigerated spermatozoa of West African Dwarf (WAD) bucks. Pooled semen from five intact WAD bucks was diluted with extender containing egg yolks from Normal feather (NF), Nickel neck (NN), Frizzle feather (FF), Nera black (NB), Oba Marshall black (OB) and Yaffa brown (YB) chickens. Following dilution, the semen samples were assessed subjectively after in vitro storage at 5oC for 24, 48, 72 and 96 hours as regards progressive sperm motility, acrosome status and abnormalities using a phase-contrast microscope. The results showed that the ability of these egg yolks to sustain progressive motility ranked in this order: OB > NN > NF >YB > NB > FF. Intact acrosome was comparable during the 24, 48, 72 and 96 hours of storage and followed similar trend across the egg-yolk types in the extender. Extender containing YB had the highest percentage abnormality at the end of this study. The findings of this study reveal that OB, NN and NF have better protective ability to maintain motility of refrigerated spermatozoa of WAD bucks.Ă
Production of Clay-Based Water Filter Using Biomass of Bacillus Subtillis, Sawdust, Activated Charcoal, Periwinkle and Snail Shell as Additives
A Significant proportion of rural households lacked access to improved and safe drinking water due to chemical and microbial contamination. Point-of-use (POU) water filters made from cheap, locally available ceramic materials and additives can achieve quality water parameters. Ceramic water filters were prepared by combining clay minerals with additives. Sawdust was used as a burnout material to achieve porosity and enhance the filtration rate. Silver nitrate, charcoal, periwinkle shell, snail shell, and biomass of Bacillus Subtilis were added in different ratios. The filter was formulated with charcoal, sawdust, snail shell, and periwinkle shell to remove microbes and treat heavy metals through the adsorption process. The filters were molded and fired in a temperature range of (700oC - 900oC). Characterization of the clay mineral, physiochemical and Microbial tests were conducted on the ceramic and water. Antimicrobial test was carried out on the biomass of Bacillus subtilis. Mineralogical (XRD) and elemental analysis of the clay, snail, and periwinkle shells showed high percentage composition of serpentine (a clay crystal), plagioclase, a mixture of feldspar minerals albite (sodium aluminosilicate - NaAlSi3O8), anorthite calcium aluminosilicate- CaAl2Si2O8) and Calcium (70-97 %composition) respectively. The results showed a greater proportion of silica in the clay, suggesting the material is silicate. Filtration rate was estimated at 1.125 L/hr. The result showed the filter has 96.72%, 99.26%, and 66.67% colony removal efficiency for heterotrophic bacteria, coliform, and fungi respectively. The filter showed about 70% - 96% efficiency for the treatment of physiochemical parameters in wastewater
Very-high-energy gamma radiation associated with the unshocked wind of the Crab pulsar
We show that the relativistic wind in the Crab pulsar, which is commonly
thought to be invisible in the region upstream of the termination shock at R <
0.1 pc, in fact could be directly observed through its inverse Compton gamm-ray
emission. The search for such specific component of radiation in the gamma-ray
spectrum of the Crab can provide unique information about the unshocked pulsar
wind that is not accessible at other wavelengths.Comment: 11 pages, 11 figures, to appear in one of the April issues of MNRA
Type IIn supernovae at z ~ 2 from archival data
Supernovae have been confirmed to redshift z ~ 1.7 for type Ia (thermonuclear
detonation of a white dwarf) and to z ~ 0.7 for type II (collapse of the core
of the star). The subclass type IIn supernovae are luminous core-collapse
explosions of massive stars and, unlike other types, are very bright in the
ultraviolet, which should enable them to be found optically at redshifts z ~ 2
and higher. In addition, the interaction of the ejecta with circumstellar
material creates strong, long-lived emission lines that allow spectroscopic
confirmation of many events of this type at z ~ 2 for 3 - 5 years after
explosion. Here we report three spectroscopically confirmed type IIn
supernovae, at redshifts z = 0.808, 2.013 and 2.357, detected in archival data
using a method designed to exploit these properties at z ~ 2. Type IIn
supernovae directly probe the formation of massive stars at high redshift. The
number found to date is consistent with the expectations of a locally measured
stellar initial mass function, but not with an evolving initial mass function
proposed to explain independent observations at low and high redshift.Comment: 8 pages, 2 figures, includes supplementary informatio
Geometrical tests of cosmological models. III. The cosmology-evolution diagram at z=1
The rotational velocity of distant galaxies, when interpreted as a size
(luminosity) indicator, may be used as a tool to select high redshift standard
rods (candles) and probe world models and galaxy evolution via the classical
angular diameter-redshift or Hubble diagram tests. We implement the proposed
testing strategy using a sample of 30 rotators spanning the redshift range
0.2<z<1 with high resolution spectra and images obtained by the VIMOS/VLT Deep
Redshift Survey (VVDS) and the Great Observatories Origins Deep Survey (GOODs).
We show that by applying at the same time the angular diameter-redshift and
Hubble diagrams to the same sample of objects (i.e. velocity selected galactic
discs) one can derive a characteristic chart, the cosmology-evolution diagram,
mapping the relation between global cosmological parameters and local
structural parameters of discs such as size and luminosity. This chart allows
to put constraints on cosmological parameters when general prior information
about discs evolution is available. In particular, by assuming that equally
rotating large discs cannot be less luminous at z=1 than at present (M(z=1) <
M(0)), we find that a flat matter dominated cosmology (Omega_m=1) is excluded
at a confidence level of 2sigma and an open cosmology with low mass density
(Omega_m = 0.3) and no dark energy contribution is excluded at a confidence
level greater than 1 sigma. Inversely, by assuming prior knowledge about the
cosmological model, the cosmology-evolution diagram can be used to gain useful
insights about the redshift evolution of the structural parameters of baryonic
discs hosted in dark matter halos of nearly equal masses.Comment: 14 pages and 11 figures. A&A in pres
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Scintillometry in urban and complex environments: a review
Knowledge of turbulent exchange in complex environments is relevant to a wide range of hydro-meteorological applications. Observations are required to improve understanding and inform model parameterisations but the very nature of complex environments presents challenges for measurements. Scintillometry offers several advantages as a technique for providing spatially-integrated turbulence data (structure parameters and fluxes), particularly in areas that would be impracticable to monitor using eddy covariance, such as across a valley, above a city or over heterogeneous landscapes. Despite much of scintillometry theory assuming flat, homogeneous surfaces and ideal conditions, over the last 20 years scintillometers have been deployed in increasingly complex locations, including urban and mountainous areas. This review draws together fundamental and applied research in complex environments, to assess what has been learnt, summarise the state-of-the-art and identify key areas for future research. Particular attention is given to evidence, or relative lack thereof, of the impact of complex environments on scintillometer data. Practical and theoretical considerations to account for the effects of complexity are discussed, with the aim of developing measurement capability towards more reliable and accurate observations in future. The usefulness of structure parameter measurements (in addition to fluxes, which must be derived using similarity theory) should not be overlooked, particularly when comparing or combining scintillometry with other measurement techniques and model simulations
The mass distribution of a moderate redshift galaxy group and brightest group galaxy from gravitational lensing and kinematics
The gravitational lens system CLASS B2108+213 has two radio-loud lensed
images separated by 4.56 arcsec. The relatively large image separation implies
that the lensing is caused by a group of galaxies. In this paper, new optical
imaging and spectroscopic data for the lensing galaxies of B2108+213 and the
surrounding field galaxies are presented. These data are used to investigate
the mass and composition of the lensing structure. The redshift and stellar
velocity dispersion of the main lensing galaxy (G1) are found to be z = 0.3648
+/- 0.0002 and sigma_v = 325 +/- 25 km/s, respectively. The optical spectrum of
the lensed quasar shows no obvious emission or absorption features and is
consistent with a BL Lac type radio source. However, the tentative detection of
the G-band and Mg-b absorption lines, and a break in the spectrum of the host
galaxy of the lensed quasar gives a likely source redshift of z = 0.67.
Spectroscopy of the field around B2108+213 finds 51 galaxies at a similar
redshift to G1, thus confirming that there is a much larger structure at z ~
0.365 associated with this system. The width of the group velocity distribution
is 694 +/- 93 km/s, but is non-Gaussian, implying that the structure is not yet
viralized. The main lensing galaxy is also the brightest group member and has a
surface brightness profile consistent with a typical cD galaxy. A lensing and
dynamics analysis of the mass distribution, which also includes the newly found
group members, finds that the logarithmic slope of the mass density profile is
on average isothermal inside the Einstein radius, but steeper at the location
of the Einstein radius. This apparent change in slope can be accounted for if
an external convergence gradient, representing the underlying parent halo of
the galaxy group, is included in the mass model.Comment: 18 pages, 14 figures, 5 tables, accepted for publication in MNRA
A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph
We present a catalogue of positions, magnitudes and velocities for 3300
emission-line objects found by the Planetary Nebula Spectrograph in a survey of
the Andromeda Galaxy, M31. Of these objects, 2615 are found likely to be
planetary nebulae (PNe) associated with M31. Initial results from this survey
include: the likely non-existence of Andromeda VIII; a universal PN luminosity
function, with the exception of a small amount of obscuration, and a small
offset in normalization between bulge and disk components; very faint
kinematically-selected photometry implying no cut-off in the disk to beyond 4
scalelengths and no halo population in excess of the bulge out to 10 effective
bulge radii; disk kinematics that show significant dispersion and asymmetric
drift out to large radii, consistent with a warm flaring disk; and no sign of
any variation in kinematics with PN luminosity, suggesting that PNe arise from
a fairly uniform population of old stars.Comment: Accepted by MNRAS. 23 pages, 37 figures. A full resolution version is
available at http://www.astro.rug.nl/~pns/pns_pub.htm
The VIMOS VLT Deep Survey: The build-up of the colour-density relation
We investigate the redshift and luminosity evolution of the galaxy
colour-density relation using the data from the First Epoch VIMOS-VLT Deep
Survey (VVDS). The size (6582 galaxies), depth (I_AB<=24) and redshift sampling
rate of the survey enable us to reconstruct the 3D galaxy environment on
relatively local scales (R=5 Mpc) up to z~1.5. Particular attention has been
devoted to calibrate a density reconstruction scheme, which factors out survey
selection effects and reproduces in an unbiased way the underlying `real'
galaxy environment. While at lower redshift we confirm the existence of a steep
colour-density relation, with the fraction of the reddest(/bluest) galaxies of
the same luminosity increasing(/decreasing) as a function of density, this
trend progressively disappears in the highest redshift bins investigated. The
rest frame u*-g' colour-magnitude diagram shows a bimodal pattern in both low
and high density environments up to z~1.5. We find that the bimodal
distribution is not universal but strongly depends upon environment: at lower
redshifts the colour-magnitude diagrams in low and high density regions are
significantly different while the progressive weakening of the colour-density
relation causes the two bimodal distributions to nearly mirror each other in
the highest redshift bin investigated. Both the colour-density and the
colour-magnitude-density relations appear to be a transient, cumulative product
of genetic and environmental factors operating over at least a period of 9 Gyr.
These findings support an evolutionary scenario in which star formation/gas
depletion processes are accelerated in more luminous objects and in high
density environments: star formation activity is shifting with cosmic time
towards lower luminosity (downsizing), and out of high density environments.Comment: 17 pages, 10 figures, figures added, accepted by A&
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