Heavy metals contamination of Chrysichthys nigrodigitatus and Lates niloticus in Ikere Gorge, Oyo state, Nigeria

This study investigates the presence of heavy metal contamination of Chrysichthys nigrodigitatus and Lates niloticus. Adult C. nigrodigitatus and L. niloticus were obtained from fishermen in Ikere Gorge, Oyo state, Nigeria. Water samples were also collected during the wet and dry seasons of the year in the same locality. The presence of five metals were analyzed in both fish and water. Iron, copper, zinc, lead and manganese were investigated by atomic absorption spectrosocopy (AAS) in two separate experiments. In each case, four tissues; gills, bone, intestine and muscle were compared with the level of metals in the water. Lower concentrations of metals were recorded in water than in fish. Lower concentration of the metals found in fish and water was less than that recommended by the World Health Organisation (WHO) guideline for maximum concentration recorded in the tissue of the two samples. Iron was found to be dominant in the intestine of C. nigrodigitatus, while manganese was found to be highest in the bone of L. niloticus, copper recorded the least of all the metals. There is significant difference (P < 0.05) in heavy metals concentration in the gill of C. niloticus and water, as well as the concentration in the intestine of L. niloticus and water. It was concluded that though the heavy metals of interest were present in measurable quantities, they were still within safe limits for consumption.Key words: Heavy metals, fish, gorge, contamination

Conceptual design of a hybrid thermal and photovoltaic receiver of an FMDF collector

The optical characteristic of a Fixed Mirror Distributed Focus (FMDF) solar collector is used as a basis for the design of an hybrid thermal and photovoltaic (PV) receiver. The result provides another variation in energy conversion that an FMDF solar collector can conveniently perform

Effects of experimental Neisseria meningitis W135 infection on serotoninergic parameters in mice

This study investigated the effects of Neisseria menigitidis W135 infection via intraperitoneal route on plasma free tryptophan concentration, brain serotonin and 5-hydroxyindole acetic acid (5-HIAA) levels in albino mice fed normal and tryptophan-enriched diets. The kinetics of appearance of viable bacteria in the blood, brain and liver following infection were also investigated. The serotoninergic parameters were determined by colorimetric and HPLC methods while colony counts were measured by plate count technique. Compared to normal diet, the tryptophan-enriched diet resulted in significantly (

Teneurs de métaux traces dans des sols à maraîchers dans la ville d’Abidjan (Côte d’Ivoire)

L’objectif principal de cette étude est l’évaluation de l’état de contamination en métaux traces de sols cultivés dans la ville d’Abidjan. Pour ce faire, des sols ont été prélevés dans des fosses pédologiques sur les sites maraîchers de Marcory et Cocody et sur la ferme expérimentale de l’Université d’Abobo-Adjamé. L’analyse des échantillons a révélé que sur les 3 sites, la quasi-totalité des horizons sont sableux, acides, riches en Mn et Fe. Les teneurs en Cd à Marcory et à Cocody, la teneur en Cu à Marcory, les teneurs en Pb à Cocody et sur la parcelle expérimentale, les teneurs en Zn sur les 3 sites, et les teneurs en Ni à Marcory et à Cocody, sont supérieures aux teneurs limites recommandées. L’acidité et la forte macroporosité des sols ont favorisé lamigration verticale des métaux traces.Mots clés: métaux traces, sols à maraîchers, Abidjan, migratio

Deformations of the hemisphere that increase scalar curvature

Consider a compact Riemannian manifold M of dimension n whose boundary \partial M is totally geodesic and is isometric to the standard sphere S^{n-1}. A natural conjecture of Min-Oo asserts that if the scalar curvature of M is at least n(n-1), then M is isometric to the hemisphere S_+^n equipped with its standard metric. This conjecture is inspired by the positive mass theorem in general relativity, and has been verified in many special cases. In this paper, we construct counterexamples to Min-Oo's conjecture in dimension n \geq 3.Comment: Revised version, to appear in Invent. Mat

Rigidity of compact Riemannian spin Manifolds with Boundary

In this article, we prove new rigidity results for compact Riemannian spin manifolds with boundary whose scalar curvature is bounded from below by a non-positive constant. In particular, we obtain generalizations of a result of Hang-Wang \cite{hangwang1} based on a conjecture of Schroeder and Strake \cite{schroeder}.Comment: English version of "G\'eom\'etrie spinorielle extrins\`eque et rigidit\'es", Corollary 6 in Section 3 added, to appear in Letters Math. Phy

Hidden Orbital Order in URu2Si2URu_{2}Si_{2}

When matter is cooled from high temperatures, collective instabilities develop amongst its constituent particles that lead to new kinds of order. An anomaly in the specific heat is a classic signature of this phenomenon. Usually the associated order is easily identified, but sometimes its nature remains elusive. The heavy fermion metal $URu_2Si_2$ is one such example, where the order responsible for the sharp specific heat anomaly at $T_0=17 K$ has remained unidentified despite more than seventeen years of effort. In $URu_{2}Si_{2}$, the coexistence of large electron-electron repulsion and antiferromagnetic fluctuations in $URu_2Si_2$ leads to an almost incompressible heavy electron fluid, where anisotropically paired quasiparticle states are energetically favored. In this paper we use these insights to develop a detailed proposal for the hidden order in $URu_2Si_2$. We show that incommensurate orbital antiferromagnetism, associated with circulating currents between the uranium ions, can account for the local fields and entropy loss observed at the $17 K$ transition; furthermore we make detailed predictions for neutron scattering measurements

Fusarium graminearum in a Papilloma Virus Infected Friesian Bull in Vom, Nigeria: Case Report

Importation of exotic cattle to improve the yield and productivityof the local 'White Fulani' breed of cattle has been on the rise inNigeria. The problem most farmers faces with the Friesian hasalways been the adaptation to the weather and endemic diseaseconditions in Nigeria. Fungal infections represent an importantcomplication for immunosuppressed animals and are associatedwith high morbidity and mortality (De Pauw and Meunier, 1999).Fusarium is one of the most important fungal genera, whichincludes many species that are pathogenic to plants and responsible for a broad range of diseases while others are highly mycotoxigenic (Viquez et al., ) and some cause opportunistic infections in humans and in farm animals. Fusarium graminearum (Gibberella zeae) is an importantpathogen of commercial crops such as wheat, maize, and rice.Infection with F. graminearum causes yield losses in grains anddegrades their nutritive, physical and chemical qualities, resultingin their being used for animal feed rather than for human consumption (Charmley et al., 1994). A contaminated crop can be salvaged by feeding it to livestock or poultry, but further losses may be incurred due to the negative effects of mycotoxins on animal performance. Potent toxins such as the estrogenic toxin zearalenone (F-2) have been reported by Vesonder and Hesseltine, (1980) but the most common mycotoxins produced byF. graminearum are deoxynivalenol (DON, also known as vomitoxin), 15-acetyldeoxynivalenol, and nivalenol belonging to a group of compounds known as trichothecenes (Homdork et al., 2000; Council for Agricultural Science and Technology, CAST, 2003). These mycotoxins are known to diminish feed consumption in domestic livestock, especially swine (CAST 2003). Because of their apparent tolerance for higher levels of dietary DON, Fusarium-infested grains are often fed to cattle or sheep asopportunity feeds. This may be due to little or insufficient information describing the pathogenesis and the ability of this plant pathogen to survive as they move through the gastrointestinal tract of cattle or on a compromised skin (Kedar and Gemerlyn, 2008)