381 research outputs found
Response of clarias gariepinus to dietary castor seeds processed by different methods
Castor seed variously treated by boiling, roasting, boiling and roasting, decorticated lyle treated, boiling and fermenting was tested for improved nutrient content and elimination of toxins. 10% processed castor seed cake (CSC) was included in diets and fed to 180 catfishes for 4-weeks to assay the dietary castor seed based on performance and some biochemical indices. Processing methods other than boiling improved performance and other measured parameters and some diets containing treated CSC produced results even better than that obtained on the conventional diet (p < 0.05). Dietary boiled CSC elicited low feed intake, body weight gain, poor feed efficiency and high mortality of the fed fish relative to the control diet (p < 0.05). Similarly, boiled CSC in diet gave poor results on biological values of specific growth rate, net protein utilization, nitrogen metabolism, protein efficiency ratio compared to the control diet or diets containing CSC treated by methods other than boiling (p < 0.05). The best result was obtained on the diet containing castor seeds treated by boiling followed by roasting (p < 0.05). For optimum utilization of CSC in nutrition of fish, it has to be boiled and roasted
Performance and nutrients digestibility of piglets fed ditary detoxified balanites augyptiaca friuts
A feeding trial was conducted to assess the effect of dietary detoxified Nigerian Balanites aegyptiaca fruits on performance and nutrients digestibility of weanling pigs. Twenty pigs weighing averagely 4.5 ± 0.85kg were used for the experiment which lasted for one month. The pigs were randomly allocated to the five dietary treatments in a completely randomized design. Five diets made of a corn-soy control diet and four others to which 20% of boiled, roasted, boiled and roasted, boiled and fermented respectively were used. Feed consumption and weight gain of pigs maintained on the Balanites based diets were comparable with the conventional diet (p > 0.05). However, efficiency of feed utilization on the Balanites containing diets was inferior to that on the control diet (p 0.05) but protein and fatdigestibility were significantly influenced by dietary Balanites (p 0.05). Nitrogen consumption using indices of protein intake, fecal nitrogen output, daily retainednitrogen and nitrogen retention coefficient were not significantly different from values obtained on the control diet (p > 0.05). It was therefore concluded that Balanites aegyptiaca fruits, when detoxified by any of the traditional methods adopted, could be incorporated in diets for livestock even up to 70% inclusion level without deleterious effects on animal consuming the feed
Invasion by Exotic Earthworms Alters Litter- and Soil-dwelling Oribatid Mites
Exotic earthworms are drivers of biotic communities in invaded North American forest stands. Here we used ecologically important oribatid mite (Arachnida: Acari) communities, as model organisms to study the responses of litter- and soil-dwelling microarthropod communities to exotic earthworm invasion in a northern temperate forest. Litter- and soil-dwelling mites were sampled in 2008–2009 from forest areas: (1) with no earthworms; (2) those with epigeic and endogeic species, including Lumbricus rubellus Hoffmeister; and (3) those with epigeic, endogeic, and anecic earthworms including L. terrestris L. Species richness and diversity of litter- and soil-dwelling (0–2 cm soil depth) oribatid mites was 1–2 times higher in sites without earthworms than in sites with worms. Similarly, litter-dwelling oribatid mites were between 72 and 1,210 times more abundant in earthworm-free sites than in sites with worms. Among earthworm invaded sites, abundance of litter-dwelling oribatid mites in sites without the anecic L. terrestris was twice as high in May and 28 times higher in October, compared to sites with L. terrestris. Species richness, diversity, and abundance of oribatid mites were greater in litter-layers than in the soil-layers that showed a varied response to earthworm invasion. Species compositions of both litter- and soil-dwelling oribatid mite communities of forests with no earthworms were markedly different from those with earthworms. We conclude that exotic earthworm invasions are associated with significant declines of species diversity, numbers, and compositional shifts in litter- and soil-inhabiting communities. These faunal shifts may contribute to earthworm effects on soil processes and food web dynamics in historically earthworm-free, northern temperate forests
Prospects and constraints on utilization of Jatropha curcas seeds in animal feedstuff
Combined physical, chemical and biochemical methods were used to process virgin seed meal of Jatropha curcas L. into treated Jatropha Seed Meal (JSM). Graded levels (0, 5, 10, 15, 20 and 25%) JSM treated by the various methods was included in the test diets which were fed ad libitum to 360 albino rats for a month in a single factor design trial. The results revealed that feed intake was numerically highest (p > 0.05) for the rats on the 5 % treated JSM diet, while feed efficiency was highest (p > 0.05) for those on the 10 % treated JSM diets. Weight gain was significantly highest (p< 0.05) for the rats on 10 and 15 % treated JSM diets. Lowest survival rate (17%) was observed on treated JSM diet processed by boiling, roasting followed by fermenting. Biochemical indices measured on treated JSM based diets were comparable with those obtained on the conventional diet (p > 0.05) except for blood cholesterol level (p < 0.05) which was elevated with increasing treated JSM in diets. There were also no significant differences recorded on AST and ALP activities (p > 0.05) between the treatments. Haematological indices investigated including PCV, RBC, Hb were insignificantly influenced by the 5% dietary treated JSM compared with the control diet (p > 0.05) and there was non-significant effect of the dietary treatment on the WBC differential counts of lymphocytes, eosinophils, monocytes and neutrophils. It was established in this study that inclusion of 5% treated JSM in diets had no detrimental effect on albino rats. Further researches are in progress to investigate inclusion of the treated JSM in diets at levels higher than the 5% used in this study.Keywords: JSM, Cockerels, Performance, Biochemical and haematological parameter
Quantification of aggregate grain shape characteristics using 3-D laser scanning technology
Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.Aggregate shape and surface characteristics influence the performance of both bound and unbound pavement materials. This paper presents some results of an on-going study on the characterization of aggregates using a three-dimensional (3-D) laser scanner technology. A sample of coarse aggregate andesite particles passing 19.0 mm and retained on 13.2 mm sieve was used for the study. The 3-D images from the laser scanning device were fully utilized in quantifying the shape descriptors in order to identify the differences between individual aggregates. It was possible to quantify differences in particle shape characteristics at the small particle scale. The study has demonstrated the advantages of the innovative 3-D laser scanning technology to quantify the shape characteristics of aggregate particles.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology.
The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zamv201
Endothelial Mitogen-Activated Protein Kinase Kinase Kinase Kinase 4 Is Critical for Lymphatic Vascular Development and Function
The molecular mechanisms underlying lymphatic vascular development and function are not well understood. Recent studies have suggested a role for endothelial cell (EC) mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) in developmental angiogenesis and atherosclerosis. Here, we show that constitutive loss of EC Map4k4 in mice causes postnatal lethality due to chylothorax, suggesting that Map4k4 is required for normal lymphatic vascular function. Mice constitutively lacking EC Map4k4 displayed dilated lymphatic capillaries, insufficient lymphatic valves, and impaired lymphatic flow; furthermore, primary ECs derived from these animals displayed enhanced proliferation compared with controls. Yeast 2-hybrid analyses identified the Ras GTPase-activating protein Rasa1, a known regulator of lymphatic development and lymphatic endothelial cell fate, as a direct interacting partner for Map4k4. Map4k4 silencing in ECs enhanced basal Ras and extracellular signal-regulated kinase (Erk) activities, and primary ECs lacking Map4k4 displayed enhanced lymphatic EC marker expression. Taken together, these results reveal that EC Map4k4 is critical for lymphatic vascular development by regulating EC quiescence and lymphatic EC fate
A study of the influence of coarse aggregate shape characteristics on permanent deformation of asphalt mixes.
Paper presented at the 32nd Annual Southern African Transport Conference 8-11 July 2013 "Transport and Sustainable Infrastructure", CSIR International Convention Centre, Pretoria, South Africa.The effect of aggregate shape properties such as angularity, texture, sphericity, roundness, flat and elongation on the performance of asphalt mixes have not been thoroughly investigated using direct measurement techniques. This is partly because aggregates do not have regular shapes, and it is a daunting task to accurately determine these properties. In this paper, three types of aggregates are used to produce asphalt mixes in order to study the effect of coarse aggregate shape properties on the permanent deformation. A modern three-dimensional (3-D) laser scanning device available at the Council for Scientific and Industrial Research (CSIR) in South Africa was used to directly obtained shape properties of the aggregates. Permanent deformation tests were conducted in the laboratory on three different mixes produced from the aggregates to compare performance. It was found that the three asphalt mixes have different resistance to permanent formation. The aggregates with high surface texture and angularity improve resistance to permanent deformation of the asphalt mix when compared with those with more rounded or spherical shapes.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology.
The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zamv201
Analytical modelling of visco-elastic behaviour of hot-mix asphalt
Paper presented at the 31st Annual Southern African Transport Conference 9-12 July 2012 "Getting Southern Africa to Work", CSIR International Convention Centre, Pretoria, South Africa.As part of the revision of the South African Pavement Design Method (SAPDM), laboratory testing was conducted to obtain the dynamic (Complex) modulus |E*| of hot-mix asphalt (HMA) samples. Dynamic modulus gives an indication of linear visco-elastic (LVE) behaviour of HMA materials at different temperatures and loading frequencies; and is required for computation of stresses, strains and displacements in flexible pavement analysis and design. Laboratory tests to obtain dynamic modulus are normally conducted at limited range of temperatures and loading frequencies. In order to characterize HMA mixes for pavement analysis, sigmoidal function master curves are constructed at different temperatures and loading frequencies using a time-temperature superposition principle.
Instead of using the sigmoidal function, this paper presents an alternative approach for characterising the LVE behaviour of HMA materials. This approach is based on the use of three rheological models, namely, Burger’s, Huet-Sayegh and the generalised 2S2P1D. The model parameters for all three rheological models were successfully determined. The master curves were developed for all HMA mixes studied. The Cole-Cole and the Black diagrams were determined. Based on the results presented in this paper, the Huet-Sayegh and the Generalised 2S2P1D models appear to predict the LVE behaviour of HMA mixes more effectively than the Burger’s model.This paper was transferred from the original CD ROM created for this conference. The material was published using Adobe Acrobat 10.1.0 Technology.
The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: nigel@doctech URL: http://www.doctech.co.zadm201
Do Vietnamese state-dominated listed firms face finance constraints?
Using accounting data of listed firms on the Vietnamese stock market this study documents that listed Vietnamese firms still face finance constraints, even after the introduction and rapid growth of the equity markets and the privatization wave that started since 1992. Contrary to most of the existing literature, especially large state-dominated firms were documented to be significantly more financially constrained.The cash flow sensitivity differences between the statedominated and private firms are economically large but statistically not significant.These findings are still consistent for both stock exchanges of Vietnam (HOSE and HNX)
The Bethe-Ansatz for N=4 Super Yang-Mills
We derive the one loop mixing matrix for anomalous dimensions in N=4 Super
Yang-Mills. We show that this matrix can be identified with the Hamiltonian of
an integrable SO(6) spin chain with vector sites. We then use the Bethe ansatz
to find a recipe for computing anomalous dimensions for a wide range of
operators. We give exact results for BMN operators with two impurities and
results up to and including first order 1/J corrections for BMN operators with
many impurities. We then use a result of Reshetikhin's to find the exact
one-loop anomalous dimension for an SO(6) singlet in the limit of large bare
dimension. We also show that this last anomalous dimension is proportional to
the square root of the string level in the weak coupling limit.Comment: 35 pages, 3 figures, LaTeX; v2 references added, typos corrected,
\Lambda fixed; v3 expanded discussion of higher loops in conclusion, matches
published versio
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