481 research outputs found
"My bones shall rise again" : war veterans, spirits and land reform in Zimbabwe
Zimbabawe's land reform programme has attracted the attention of many commentators and has elicited a multiplicity of interpretations. By and large, however, this exercise has been politicized, that is, those who have criticized or justified the programme have done so on political or economic grounds. The relationship between land and indigenous religion has not been sufficiently examined. The present paper explores this relationship through an analysis of the reburial of fallen heroes, spearheaded by Zimbabwean war veterans. It argues that the reburial activities reflect Zimbabwe's incorporation of religion into political discourse and that the Shona people understand this link in terms of their traditional cosmology. As ritual practice, reburials are effective tools for shaping the politics of restitution, nationbuilding and moral accountability. [Book abstract
Low energy effective action on a self-gravitating D-brane
Recently the study of braneworld on the self-gravitating D-brane has been
initiated and derived the gravitational equation on the brane by holographic
and geometrical projection methods. Surprisingly, in common with these two
methods, the matter on the brane cannot be the source of the gravity on the
brane at leading order. In this paper we will propose the low energy effective
action on the D-brane coupled with gravity which derives the same results.Comment: 8 pages, minor corrections, accepted for publication in Physical
Review
Observation of the Halo of NGC 3077 Near the "Garland" Region Using the Hubble Space Telescope
We report the detection of upper main sequence stars and red giant branch
stars in the halo of an amorphous galaxy, NGC3077. The observations were made
using Wide Field Planetary Camera~2 on board the Hubble Space Telescope. The
red giant branch luminosity function in I-band shows a sudden discontinuity at
I = 24.0 +- 0.1 mag. Identifying this with the tip of the red giant branch
(TRGB), and adopting the calibration provided by Lee, Freedman, & Madore (1993)
and the foreground extinction of A_B = 0.21 mag, we obtain a distance modulus
of (m-M)_0 = 27.93 +- 0.14(random) +- 0.16(sys). This value agrees well with
the distance estimates of four other galaxies in the M81 Group. In addition to
the RGB stars, we observe a concentration of upper main sequence stars in the
halo of NGC3077, which coincides partially with a feature known as the
``Garland''. Using Padua isochrones, these stars are estimated to be <150 Myrs
old. Assuming that the nearest encounter between NGC3077 and M81 occurred 280
Myrs ago as predicted by the numerical simulations (Yun 1997), the observed
upper main sequence stars are likely the results of the star formation
triggered by the M81-NGC3077 tidal interaction.Comment: 15 pages, 8 figures. Accepted for publication in Astrophysical
Journa
Morphological and molecular characterisation of Streptomyces spp. which suppress pathogenic fungi
Streptomyces species are aerobes and chemoorganotrophic bacteria. These
microorganisms produce a wide range of industrially significant
compounds, specifically antibiotics and anti fungal substances. The
objective of this study was to characterise soil-borne Streptomyces
isolates using morphological and molecular traits in order to identify
them to species level, and leverage from their potential to suppress
the growth of Aspergillus flavus , Fusarium oxysporum and
Penicillium italicum . Twenty-seven soil-borne putative Streptomyces,
which elicited comprehensive\ua0antimicrobial activity against
Aspergillus flavus, Fusarium oxysporum and Penicillium italicum, in a
previous study, were evaluated. On the basis of morphology, the
bacteria resembled the genus Streptomyces. Initially, colonies
phenotypically appeared to have a relatively smooth surface but as
growth progressed the bacteria developed a weft of aerial mycelium
granular, powdery or velvety in appearance. Bacteria produced a wide
variety of pigments which in turn were responsible for the colour of
the vegetative and aerial mycelia, colour ranged from white to cream or
buff shades and yellow to orange or brown. Microscopic analyses and
morphological characteristics generated sub-groups of the isolates and
clustered them according to their similarities. One bacterial strain
was randomly selected from each cluster and investigated using
molecular characteristics. Partial 16S rDNAs from the selected
representative isolates from each subgroup, were sequenced and
phylogenetic analysis performed. The 16S\ua0rDNA\ua0sequences of
the isolates indicated that they were related to\ua0 Streptomyces
species: S. bungoensis , S. thermocarboxydus , S. corchorusii and
S. lasaliensis, that are known secondary metabolite producers
possessing antimicrobial activity against plant pathogens.Les esp\ue8ces de Streptomyces sont des bact\ue9ries
a\ue9robies et chimio-organotrophes. Ces micro-organismes produisent
une large gamme de compos\ue9s d\u2019importance industrielle, en
particulier des antibiotiques et des substances antifongiques.
L\u2019objectif de cette \ue9tude \ue9tait de caract\ue9riser
les isolats de Streptomyces transmis par le sol \ue0 l\u2019aide de
traits morphologiques et mol\ue9culaires afin de les identifier au
niveau de l\u2019esp\ue8ce, et de tirer parti de leur potentiel
\ue0 supprimer la croissance d\u2019 Aspergillus flavus , Fusarium
oxysporum et Penicillium italicum . Vingt-sept Streptomyces putatifs
transmis par le sol, qui ont suscit\ue9 une activit\ue9
antimicrobienne compl\ue8te contre Aspergillus flavus, Fusarium
oxysporum et Penicillium italicum, dans une \ue9tude
pr\ue9c\ue9dente, ont \ue9t\ue9 \ue9valu\ue9s. Sur la base
de la morphologie, les bact\ue9ries ressemblaient au genre
Streptomyces. Au d\ue9part, les colonies semblaient
ph\ue9notypiquement avoir une surface relativement lisse, mais au fur
et \ue0 mesure que la croissance progressait, les bact\ue9ries
d\ue9veloppaient une trame de myc\ue9lium a\ue9rien
d\u2019aspect granuleux, poudreux ou velout\ue9. Les bact\ue9ries
produisaient une grande vari\ue9t\ue9 de pigments qui \ue0 leur
tour \ue9taient responsables de la couleur des myc\ue9liums
v\ue9g\ue9tatifs et a\ue9riens, la couleur variait du blanc au
cr\ue8me ou au chamois et du jaune \ue0 l\u2019orange ou au brun.
Des analyses microscopiques et des caract\ue9ristiques morphologiques
ont g\ue9n\ue9r\ue9 des sous-groupes d\u2019isolats et les ont
regroup\ue9s en fonction de leurs similitudes. Une souche
bact\ue9rienne a \ue9t\ue9 s\ue9lectionn\ue9e au hasard dans
chaque groupe et \ue9tudi\ue9e en utilisant des
caract\ue9ristiques mol\ue9culaires. Des ADNr 16S partiels
provenant des isolats repr\ue9sentatifs s\ue9lectionn\ue9s de
chaque sous-groupe ont \ue9t\ue9 s\ue9quenc\ue9s et une analyse
phylog\ue9n\ue9tique a \ue9t\ue9 effectu\ue9e. Les
s\ue9quences d\u2019ADNr 16S des isolats ont indiqu\ue9
qu\u2019ils \ue9taient apparent\ue9s aux esp\ue8ces de
Streptomyces: S. bungoensis , S. thermocarboxydus , S. corchorusii
et S. lasaliensis, qui sont des producteurs de m\ue9tabolites
secondaires connus poss\ue9dant une activit\ue9 antimicrobienne
contre les phytopathog\ue8nes
In vitro suppression of pathogenic fungi by Streptomyces spp.
The use of living organisms or natural enemies of pathogens to control
their populations is called biological disease control. It involves
harnessing and introduction of exotic species of microorganism in a
natural form, with the intention of controlling pathogens that may
exist naturally in the same ecosystem. Prospects for biological control
of Aspergillus flavus , Fusarium oxysporum and Penicillium italicum
were investigated using Streptomyces spp. isolated from Chinhoyi
University of Technology Farm soils in Mashonaland West, Zimbabwe.
Twenty seven Streptomyces spp were obtained from the soil, and screened
for antimicrobial activity and antagonism in in vitro pathogen
inhibition assays, replicated thrice. Although majority of the isolates
tested elicited no effect on test pathogens, 22% of the Streptomyces
isolates were able to effectively suppress A. flavus, F. oxysporum and
P. italicum by at least 55%. There was a significant interaction
between Streptomyces isolates and pathogen (A. flavus, F. oxysporum and
P. italicum) (P<0.05) on fungal radial growth at days 7, 10 and 14
after pathogen-Streptomyces incubation. Antimicrobial potential against
individual and multiple test pathogens was observed, with
CUT-Streptomyces 4, CUT-Streptomyces 10, CUT-Streptomyces 11,
CUT-Streptomyces 20 and CUT-Streptomyces 23 showing the greatest
antimicrobial activity. CUT-Streptomyces isolates have the potential to
suppress A. flavus, F. oxysporum and P. italicum in vitro.L\u2019utilisation d\u2019organismes vivants ou d\u2019ennemis
naturels d\u2019agents pathog\ue8nes pour contr\uf4ler leurs
populations est appel\ue9e contr\uf4le biologique des maladies. Il
s\u2019agit d\u2019exploiter et d\u2019introduire des esp\ue8ces
exotiques de microorganismes sous une forme naturelle, dans le but de
contr\uf4ler les agents pathog\ue8nes pouvant exister naturellement
dans le m\ueame \ue9cosyst\ue8me. Les perspectives de lutte
biologique contre Aspergillus flavus , Fusarium oxysporum et
Penicillium italicum ont \ue9t\ue9 \ue9tudi\ue9es \ue0
l\u2019aide de Streptomyces spp. isol\ue9es des sols agricoles de
l\u2019Universit\ue9 de Technologie de Chinhoyi \ue0 Mashonaland
West, Zimbabwe. Vingt-sept Streptomyces spp ont \ue9t\ue9 obtenus
du sol et cribl\ue9s pour l\u2019activit\ue9 antimicrobienne et
l\u2019antagonisme dans des tests d\u2019inhibition des agents
pathog\ue8nes in vitro, r\ue9pliqu\ue9s trois fois. Bien que la
majorit\ue9 des isolats test\ue9s ne provoquent aucun effet sur les
agents pathog\ue8nes test\ue9s, 22% des isolats de Streptomyces
sont capables de supprimer efficacement au moins 55% des A. flavus, F.
oxysporum et P. italicum. Il y avait une interaction significative
entre les isolats de Streptomyces et l\u2019agent pathog\ue8ne (A.
flavus, F. oxysporum et P. italicum) (P< 0.05) lors de la croissance
radiale des champignons aux 7\ue8me, 10\ue8me et 14\ue8me jours
apr\ue8s l\u2019incubation de l\u2019agent
pathog\ue8ne-Streptomyces. Un potentiel antimicrobien contre des
agents pathog\ue8nes individuels et multiples a \ue9t\ue9
observ\ue9. CUT-Streptomyces 4, CUT-Streptomyces 10, CUT-Streptomyces
11, CUT-Streptomyces 20 et CUT-Streptomyces 23 ont montr\ue9
l\u2019activit\ue9 antimicrobienne la plus \ue9lev\ue9e. Les
isolats de CUT-Streptomyces ont le potentiel de supprimer A. flavus, F.
oxysporum et P. italicum in vitro
The Tip of the Red Giant Branch Distance to the Large Magellanic Cloud
We present the I-band luminosity function of the red giant branch stars in
the Large Magellanic Cloud (LMC) using the data from the Magellanic Clouds
Photometric Survey (Zaritsky, Harris & Thompson, 1997). Selecting stars in
uncrowded, low-extinction regions, a discontinuity in the luminosity function
is observed at I_0 = 14.54 mag. Identifying this feature with the tip of the
red giant branch (TRGB), and adopting an absolute TRGB magnitude of -4.05 +-
0.04 mag based on the calibration of Lee, Freedman & Madore (1993), we obtain a
distance modulus of 18.59 +- 0.09 (random) +- 0.16 (systematic) mag. If the
theoretical TRGB calibration provided by Cassisi & Salaris (1997) is adopted
instead, the derived distance would be 4% greater. The LMC distance modulus
reported here, 18.59 +- 0.09, is larger by 0.09 mag (1-sigma) than the value
that is most commonly used in the extragalactic distance scale calibrated by
the period-luminosity relation of the Cepheid variable stars. Our TRGB distance
modulus agrees with several RR Lyrae distances to the LMC based on HIPPARCOS
parallaxes. Finally, we note that using the same MCPS data, we obtain a
distance modulus of 18.29 +- 0.03 mag using the red clump method, which is
shorter by 0.3 mag compared to the TRGB estimate.Comment: 19 pages, 5 figure
Volatile constituents of fruit pulp of Strychnos cocculoides (Baker) growing in Malawi using solid phase microextraction
Volatile constituents of the edible pulp of Strychnos cocculoides (Monkey orange) were extracted using solid phase microextraction (SPME) and their identity established by GC–FID and GC–MS systems. Six compounds
were extracted and identified: isobutyl acetate, 53.2%; 2-methylbutyl acetate, 12.8%; ethyl-2-methylbutyrate,
10.5%; 2, 6-ditetrabutyl-4-methyl-phenol, 8.4%; butyl-2-methyl butyrate, 6.7% and geranyl acetate, 3.1%.
These accounted for 94.7% of the volatile constituents in the pulp. Thus, the acetate and butyrate esters
were the most abundant volatiles in the edible pulp of the ripe fruit.Carnegie Regional Initiative in Science Education (Carnegie-RISE) through the Southern Africa Biochemistry and Informatics for Natural Products (SABINA) network and the ACP EU through the POL-SABINA network.
Open Access funded by SAAB.http://www.elsevier.com/locate/sajbhb2016Biochemistr
The enigmatic pair of dwarf galaxies Leo IV and Leo V: coincidence or common origin?
We have obtained deep photometry in two 1x1 degree fields covering the close
pair of dwarf spheroidal galaxies (dSph) Leo IV and Leo V and part of the area
in between. We find that both systems are significantly larger than indicated
by previous measurements based on shallower data and also significantly
elongated. With half-light radii of r_h=4'.6 +- 0'.8 (206 +- 36 pc) and
r_h=2'.6 +- 0'.6 (133 +- 31 pc), respectively, they are now well within the
physical size bracket of typical Milky Way dSph satellites. Their ellipticities
of epsilon ~0.5 are shared by many faint (M_V>-8) Milky Way dSphs. The large
spatial extent of our survey allows us to search for extra-tidal features with
unprecedented sensitivity. The spatial distribution of candidate red giant
branch and horizontal branch stars is found to be non-uniform at the ~3 sigma
level. This substructure is aligned along the direction connecting the two
systems, indicative of a possible `bridge' of extra-tidal material. Fitting the
stellar distribution with a linear Gaussian model yields a significance of 4
sigma for this overdensity, a most likely FWHM of ~16 arcmin and a central
surface brightness of ~32 mag arcsec^{-2}. We investigate different scenarios
to explain the close proximity of Leo IV and Leo V and the possible tidal
bridge between them. Orbit calculations demonstrate that they are unlikely to
be remnants of a single disrupted progenitor, while a comparison with
cosmological simulations shows that a chance collision between unrelated
subhalos is negligibly small. Leo IV and Leo V could, however, be a bound
`tumbling pair' if their combined mass exceeds 8 +- 4 x 10^9 M_sun. The
scenario of an internally interacting pair appears to be the most viable
explanation for this close celestial companionship. (abridged)Comment: 9 pages, 8 figures, small number of minor textual changes, accepted
for publication in Astrophysical Journa
The Hubble Space Telescope Key Project on the Extragalactic Distance Scale XXIV: The Calibration of Tully-Fisher Relations and the Value of the Hubble Constant
This paper presents the calibration of BVRIH$ Tully-Fisher relations based on
Cepheid distances to 21 galaxies within 25 Mpc, and 23 clusters within 10,000
km/s. These relations have been applied to several distant cluster surveys in
order to derive a value for the Hubble constant, H0, mainly concentrating on an
I-band all-sky survey by Giovanelli and collaborators which consisted of total
I magnitudes and 50% linewidth data for ~550 galaxies in 16 clusters. For
comparison, we also derive the values of H0 using surveys in B-band and V-band
by Bothun and collaborators, and in H-band by Aaronson and collaborators.
Careful comparisons with various other databases from literature suggest that
the H-band data, whose magnitudes are isophotal magnitudes extrapolated from
aperture magnitudes rather than total magnitudes, are subject to systematic
uncertainties. Taking a weighted average of the estimates of Hubble constants
from four surveys, we obtain H0 = 71 +- 4 (random) +- 7 (systematic) km/s/Mpc.
We have also investigated how various systematic uncertainties affect the value
of H0 such as the internal extinction correction method used, Tully-Fisher
slopes and shapes, a possible metallicity dependence of the Cepheid
period-luminosity relation and cluster population incompleteness bias.Comment: 34 pages, 13 figure
Peripheral Blood CD64 Levels Decrease in Crohn's Disease following Granulocyte and Monocyte Adsorptive Apheresis
Granulocyte and monocyte adsorptive apheresis (GMA) is reportedly useful as induction therapy for Crohn's disease (CD). However, the effects of GMA on CD64 have not been well characterized. We report here our assessment of CD64 expression on neutrophils before and after treatment with GMA in two patients with CD. The severity of CD was assessed with the CD activity index (CDAI). The duration of each GMA session was 60 min at a flow rate of 30 ml/min as per protocol. CD64 expression on neutrophils was measured by analyzing whole blood with a FACScan flow cytometer. In case 1, CD64 levels after each session of GMA tended to decrease compared to pretreatment levels, whereas in case 2, CD64 levels dropped significantly after treatment. The CDAI decreased after GMA in both cases 1 and 2. A significant correlation was noted between CDAI scores and CD64 levels in both cases. In conclusion, GMA reduced blood CD64 levels, which would be an important factor for the decrease of CDAI scores
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