974 research outputs found
Assessment of the Toxic Effect of Mixed Effluents from Trans-Amadi Industrial Layout on Tilapia (Oreochromis Niloticus) in Okrika River, Port Harcourt, Rivers State, Nigeria
The toxic effect of the mixed effluent (industrial, domestic and municipal) discharged into Okrika River on Tilapia (Oreochromis niloticus) was assessed. Tilapia samples were collected at about 500 meters from point of entry of mixed effluent into the River (downstream) and about 1.5 kilometers from the point of entry of mixed effluent into the River (upstream) while Tilapia from a fish pond affiliated to Rivers State Sustainable Development Authority (RSSDA) was used as control. Malondialdehyde (MDA) concentration and glutathione S-transferase (GST) activity were assayed in the liver homogenate. Alanine amino transferase, ALT; Alanine aspartate transferase, AST and Alkaline phosphatase, ALP were investigated in the fish blood serum. Histopathologic section of the liver was also examined. Results showed that liver MDA concentration increased significantly (p<0.05) in downstream samples (2.45 ± 0.77 to 6.09 ± 1.57nm/mg tissue) with no significant change in upstream liver MDA.  Also, the Hepatic GST was significantly increased in downstream (5.59 ± 1.09 to 16.80 ± 0.71 IU/L) as well as significant decrease upstream (5.59 ± 1.09 to 3.65 ± 1.48 IU/L) in comparison with the control. ALT, AST, ALP activities in the exposed fish serum showed marked increases downstream (ALT: 99.8 ± 3.5 IU/L; AST: 277.02 ± 39.8 IU/L; ALP: 40.38 ± 11.4 IU/L) at P<0.05 when compared to the control (ALT: 77.8 ± 14.3 IU/L; AST: 150.8 ± 50.7 IU/L; ALP: 15.34 ± 5.6 IU/L). Histology of the liver showed vacuolar degeneration, focal areas of necrosis and aggregation of inflammatory cells between the hepatocytes. This study elucidates negative biochemical changes on the metabolism of the fish due to the presence of mixed effluent in the River. Keywords: Toxicity, Histopatology, Tilapia, Effluent and Glutathione S-transferas
Keanekaragaman Jenis Tupai (Tupaiidae) dalam Kawasan Gunung Semahung Desa Paloan Kecamatan Sengah Temila Kabupaten Landak Diversity Of Squirrel (Tupaiidae) In Mount Semahung Paloan Village Sengah Temila Landak District
This study aims to determine the squirrel (Tupaiidae) species diversity in Hutan Lindung Gunung Semahung Paloan Village Sengah Temila Landak District. Using line method, with length 500 m and width 100 m, the plots were taken purposively where the Tupaiidae is found. Tupaiidae identification using Mammals Field Guide (Payne et al,.1985), and local people. There are 3 species of Tupaiidae found in Hutan Lindung Gunung Semahung Paloan Village namely: Tupaia minor, T.splendidula, T.gracilis, and total of 190 individuals. In the lowland area, there were 3 species of Tupaiidae were found (106 individuals), whereas in the hilly area 2 species were found (84 individuals), T.gracilis were not found in the hilly area. The Tupaiidae diversity in the area is low, showed by the diversity index below 1 (H=0,8950). Dominance index C=0,4383, means that more than one species of Tupaiidae are dominant in the area that is;T.minor and T.splendidula. Richness index D=1,5071. Evenness index is low (e=0.8146) means individuals of each species are not even, there are two dominant species (T.minor and T.splendidula), and the individuals of T.gracilis is low and only found in lowland area. Further observations are needed to obtain more comprehensive information about Tupaiidae.Keywords : Tupaiidae, species diversity, protection forest Mount Semahun
Physico-Chemical Evolution, Gill Mda Concentration And Histology Of Tilapia Exposed To Mixed Effluent In Okrika River, Rivers State, Nigeria
The physico-chemical evaluation and histological studies on Tilapia (Oreochromis niloticus) exposed to mixed effluent (industrial, domestic and municipal) from Okrika River were investigated. Tilapia samples were collected at about 500 meters from point of entry of mixed effluent into the River (downstream) and about 1.5 kilometers from the point of entry of mixed effluent into the River (upstream) while Tilapia from a fish pond affiliated to Rivers State Sustainable Development Authority (RSSDA) was used as control. Malondialdehyde (MDA) concentration was assayed in the gill homogenates in the Tilapia fish blood serum. It was observed that the biological oxygen demand (BOD), total dissolved solids (TDS), total suspended solids (TSS), conductivity, chromium and cadmium were significantly higher in concentrations in the Okrika River exceeding FEPA regulations in Nigeria. Aside chromium whose concentration was more upstream of the river, BOD, TDS, TSS, conductivity and cadmium show more concentration downstream of the river. Results showed an increase in gill MDA concentration upstream samples (0.00±0.00 to 1.51± 0.24nm/mg), downstream samples (1.51±0.24 to 2.32±0.66nm/mg) and the control samples (2.32±0.66 to 2.70±0.89nm/mg). No significant change was also observed in gill MDA concentration of both downstream and upstream samples when compared with the control. Histology of the gill showed vacuolar degeneration, focal areas of necrosis and aggregation of inflammatory cells between the hepatocytes. From the investigation, the mixed effluents discharged into the river are toxic to the marine environment. Key words: Physico-chemical, Histological, Effluent, Malondialdehyde and Tilapia
Anion emission from water molecules colliding with positive ions: Identification of binary and many-body processes
It is shown that negative ions are ejected from gas-phase water molecules
when bombarded with positive ions at keV energies typical of solar-wind
velocities. This finding is relevant for studies of planetary and cometary
atmospheres, as well as for radiolysis and radiobiology. Emission of both H-
and heavier (O- and OH-) anions, with a larger yield for H-, was observed in
6.6-keV 16O+ + H2O collisions. The ex-perimental setup allowed separate
identification of anions formed in collisions with many-body dynamics from
those created in hard, binary collisions. Most of the ani-ons are emitted with
low kinetic energy due to many-body processes. Model calcu-lations show that
both nucleus-nucleus interactions and electronic excitations con-tribute to the
observed large anion emission yield.Comment: 5 pages, 4 figure
Regulatory standards and guidance for the use of health applications for self-management in Africa: scoping review protocol
Introduction: Despite health applications becoming ubiquitous and with enormous potential to facilitate self-management, regulatory challenges such as poor application quality, breach of data privacy and limited interoperability have impeded their full adoption. While many countries now have digital health-related policies/strategies, there is also a need for regulatory standards and guidance that address key regulatory challenges associated with the use of health applications. Currently, it is unclear the status of countries in Africa regarding regulatory standards and guidance that address the use of health applications. This protocol describes the process of conducting a scoping review which aims to investigate the extent to which regulatory standards and guidance address the use of health applications for self-management within the WHO African Region countries. Methods: The review will follow the methodological framework for conducting a scoping study by Arksey and OâMalley (2005), and the updated methodological guidance for conducting a Joanna Briggs Institute (JBI) scoping review. Given that regulatory standards and guidance are unlikely to be available in scientific databases, we will search Scopus, Google, OpenGrey, WHO Regional Office for Africa Library (AFROLIB), African Index Medicus (AIM), websites of WHO, ITU and Ministries of Health, repositories for digital health policies. We will also search the reference lists of included documents, and contact key stakeholders in the region. Results will be reported using descriptive qualitative content analysis based on the review objectives. The policy analysis framework by Walt and Gilson (1994) will be used to organise findings. A summary of the key findings will be presented using tables, charts and maps. Ethics and dissemination: The collection of primary data is not anticipated in this study and hence ethical approval will not be required. The review will be published in a peer-reviewed journal while key findings will be shared with relevant organisations and/or presented at conferences
Asymptotic expansions for the escape rate of stochastically perturbed unimodal maps
The escape rate of a stochastic dynamical system can be found as an expansion
in powers of the noise strength. In previous work the coefficients of such an
expansion for a one-dimensional map were fitted to a general form containing a
few parameters. These parameters were found to be related to the fractal
structure of the repeller of the system. The parameter alpha, the "noise
dimension", remains to be interpreted. This report presents new data for alpha
showing that the relation to the dimensions is more complicated than predicted
in earlier work and oscillates as a function of the map parameter, in contrast
to other dimension-like quantities.Comment: 7 pages, 5 figure
Nonequilibrium dynamics of random field Ising spin chains: exact results via real space RG
Non-equilibrium dynamics of classical random Ising spin chains are studied
using asymptotically exact real space renormalization group. Specifically the
random field Ising model with and without an applied field (and the Ising spin
glass (SG) in a field), in the universal regime of a large Imry Ma length so
that coarsening of domains after a quench occurs over large scales. Two types
of domain walls diffuse in opposite Sinai random potentials and mutually
annihilate. The domain walls converge rapidly to a set of system-specific
time-dependent positions {\it independent of the initial conditions}. We obtain
the time dependent energy, magnetization and domain size distribution
(statistically independent). The equilibrium limits agree with known exact
results. We obtain exact scaling forms for two-point equal time correlation and
two-time autocorrelations. We also compute the persistence properties of a
single spin, of local magnetization, and of domains. The analogous quantities
for the spin glass are obtained. We compute the two-point two-time correlation
which can be measured by experiments on spin-glass like systems. Thermal
fluctuations are found to be dominated by rare events; all moments of truncated
correlations are computed. The response to a small field applied after waiting
time , as measured in aging experiments, and the fluctuation-dissipation
ratio are computed. For ,
, it equals its equilibrium value X=1, though time
translational invariance fails. It exhibits for aging regime
with non-trivial , different from mean field.Comment: 55 pages, 9 figures, revte
Supersymmetric minisuperspace with non-vanishing fermion number
The Lagrangean of supergravity is dimensionally reduced to one
(time-like) dimension assuming spatial homogeneity of any Bianchi type within
class A of the classification of Ellis and McCallum. The algebra of the
supersymmetry generators, the Lorentz generators, the diffeomorphism generators
and the Hamiltonian generator is determined and found to close. In contrast to
earlier work, infinitely many physical states with non-vanishing even fermion
number are found to exist in these models, indicating that minisuperspace
models in supergravity may be just as useful as in pure gravity.Comment: 4 page
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