Physico-chemical Characteristics of the Andoni River and its potentials for production of the Giant Tiger Prawn (Penaeus monodon) in Nigeria

The physico-chemical characteristics of Andoni River and its potentials for production of  Penaeus monodon (Fabricius 1798), an exotic species whose occurrence in Nigerian coastal waters was first reported in 1999 was investigated from March 2012 to February, 2013. Physico-chemical properties of the River were determined from water samples collected at Kaa water front on a monthly basis. Temperature was determined using Mercury-in-glass Thermometer. A Pocket-sized pH meter Hanna Instruments (pHep) was used in situ to determine the pH of the River water. Dissolved oxygen was determined using modified Winkler’s Method. Temperature ranged from 27.00± 0.320C to 31.00± 0.890C, pH varied between 5.64±0.02 to 6.92± 0.04. Salinity varied from 11.60± 0.51ppt in November to 22.80± 0.37ppt in May. Dissolved oxygen ranged from 3.86±0.37mg/l to 8.00±0.00mg/l. The values recorded were within FAO recommended range (temperature 250C - 300C, Salinity 5ppt - 40ppt and Dissolved oxygen 0.5mg/L – 8.6mg/L) for growth and development of Penaeid shrimps except for pH values which was lower than the recommended 7.5 - 9.0. The low pH was attributed to the time of sampling which for logistic reasons were carried out in the morning hours. Based on the results, it is concluded that the Andoni River is suitable for the production of the giant tiger prawn (Penaeus monodon). Keywords: Water quality, Shrimp, Niger Delta

Ichtyofaunal Composition and Seasonal Occurrence in the Bodo Creek, Niger Delta, Nigeria.

The studies of Ichthyofaunal composition and seasonal occurrence in Bodo Creek, Niger Delta Nigeria were done between the months of January to July 2010. the collection of the fishes were done with fishing traps, gill and cast nets of various mesh sizes ranging from 20 – 102mm. The months of January February and March were sampled for the wet season while the months of May, June and July were sampled for the dry season to determine the seasonal occurrence of the various fish species. The upper, middle and lower courses of the creek were also accorded cognizance during fish collection to determine the spatial dynamics in species occurrence. The identification of the fish species was done with aid of keys provided by Reed etal (1979) Tobor (1978), FAO (1981) and Schneider (1990). A total of 45 fish species belonging 36 genera and 26 families were identified. The fish families; Clupeidaeand Carangidaewere the highest in species number recording 4 species each. The fish families Bagridae, Batrachoidae, Belonidae, Cynoglossidae, Drepanidae, Eleotridae, Elopidae, Ephipidae, Gerreidae, Monodaetylidae, Periophthalmidae, Semandidae, Soleidae, Trichiuridae and Symbrachidae were the least in species number, recording 1 species each. All 45 species occurred in all courses; upper, middle and lower. Courses all 45 species also occurred in both wet and dry season, but Ethmalosafimbriata and Liza grandisquamis were more abundant in the dry season than the wet season. Keywords: Ichthyofauna, assemblage, and distribution DOI: 10.7176/ALST/74-05 Publication date:May 31st 201

The m−m-dissimilarity map and representation theory of SLmSL_m

We give another proof that $m$-dissimilarity vectors of weighted trees are points on the tropical Grassmanian, as conjectured by Cools, and proved by Giraldo in response to a question of Sturmfels and Pachter. We accomplish this by relating $m$-dissimilarity vectors to the representation theory of $SL_m.$Comment: 11 pages, 8 figure

Towards a formalism for mapping the spacetimes of massive compact objects: Bumpy black holes and their orbits

Observations have established that extremely compact, massive objects are common in the universe. It is generally accepted that these objects are black holes. As observations improve, it becomes possible to test this hypothesis in ever greater detail. In particular, it is or will be possible to measure the properties of orbits deep in the strong field of a black hole candidate (using x-ray timing or with gravitational-waves) and to test whether they have the characteristics of black hole orbits in general relativity. Such measurements can be used to map the spacetime of a massive compact object, testing whether the object's multipoles satisfy the strict constraints of the black hole hypothesis. Such a test requires that we compare against objects with the ``wrong'' multipole structure. In this paper, we present tools for constructing bumpy black holes: objects that are almost black holes, but that have some multipoles with the wrong value. The spacetimes which we present are good deep into the strong field of the object -- we do not use a large r expansion, except to make contact with weak field intuition. Also, our spacetimes reduce to the black hole spacetimes of general relativity when the ``bumpiness'' is set to zero. We propose bumpy black holes as the foundation for a null experiment: if black hole candidates are the black holes of general relativity, their bumpiness should be zero. By comparing orbits in a bumpy spacetime with those of an astrophysical source, observations should be able to test this hypothesis, stringently testing whether they are the black holes of general relativity. (Abridged)Comment: 16 pages + 2 appendices + 3 figures. Submitted to PR

Colossal dielectric permittivity of BaTiO3-based nanocrystalline ceramics sintered by spark plasma sintering

In pursuit of high permittivity materials for electronic application, there has been a considerable interest recently in the dielectric properties of various perovskite oxides like calcium copper titanate or lanthanum doped barium titanate. When processed in a particular way, this later material present at ambient temperature and at f=1 kHz unusual interesting dielectric properties, a so called “colossal” permittivity value up to several 106 with relatively low dielectric losses. Moreover and contrary to what is classically expected and evidenced for this type of materials, no temperature dependence is observed. This behavior is observed in nanopowders based ceramics. An assumption to explain the observed properties is proposed. These results have important technological applications, since these nanoceramics open a new route to the fabrication of very thin dielectric films

Entrepreneurial Intentions of Teams: Sub-Dimensions of Machiavellianism Interact With Team Resilience

Machiavellians are often seen as manipulative people who contribute negatively to teams and ventures. However, recent work has shown that Machiavellians can also cooperate and act in pro-social ways in a team context. Thus, some aspects of Machiavellianism might be conducive for teams and team members’ intentions to start a business venture. Most studies in this area have failed to (a) assess the effect of Machiavellianism at the team level, (b) take into account the dimensional nature of Machiavellianism, and (c) assess moderators of these effects. We propose that the combination of Machiavellianism and resilience in teams predict team entrepreneurial intentions (EI). Moreover, we propose that different team level dimensions of Machiavellianism (amoral manipulation, desire for status, desire for control, distrust of others) are differentially related to EI. More specifically, we expect at the team level that amoral manipulation and desire for status are positively related to changes in EI (as teams high on these dimensions feel that they can use unethical practices that give them an advantage in being successful), whereas desire for control and distrust of others should be negatively related to changes in EI (as entrepreneurial teams usually work in less structured situations and need to closely work together). Furthermore, all sub-dimensions of Machiavellianism should interact positively with team resilience as resilience acts as a buffer that protects teams from potential negative effects of Machiavellianism. In a multi-wave study among newly formed teams engaged in entrepreneurship projects, controlling for psychopathy and narcissism, we found partial support for our hypotheses. Results supported our expectations for the “amoral manipulation” and “desire for control” sub-dimensions, but not for the “desire for status” and the “distrust of others” sub-dimensions of Machiavellianism, with distrust of others showing unexpectedly opposite effects. This study contributes to the literature by looking at the dimensions of Machiavellianism at the level of entrepreneurial teams in conjunction with the more positive team characteristic, resilience. Our results indicate that the relationship between Machiavellianism and EI is more complex than previously hypothesized, as the sub-dimensions are s

Hadron Masses From Novel Fat-Link Fermion Actions

The hadron mass spectrum is calculated in lattice QCD using a novel fat-link clover fermion action in which only the irrelevant operators in the fermion action are constructed using smeared links. The simulations are performed on a 16^3 x 32 lattice with a lattice spacing of a=0.125 fm. We compare actions with n=4 and 12 smearing sweeps with a smearing fraction of 0.7. The n=4 Fat-Link Irrelevant Clover (FLIC) action provides scaling which is superior to mean-field improvement, and offers advantages over nonperturbative 0(a) improvement, including a reduced exceptional configuration problem.Comment: 12 pages, 4 figures, new simulation with mean-field improved clover, further discussion of actio

Epitaxial growth and magnetic properties of Sr2CrReO6 thin films

The double perovskite Sr2CrReO6 is an interesting material for spintronics, showing ferrimagnetism up to 635 K with a predicted high spin polarization of about 86%. We fabricated Sr2CrReO6 epitaxial films by pulsed laser deposition on (001)-oriented SrTiO3 substrates. Phase-pure films with optimum crystallographic and magnetic properties were obtained by growing at a substrate temperature of 700 degree C in pure O2 of 6.6x10-4 mbar. The films are c-axis oriented, coherently strained, and show less than 20% anti-site defects. The magnetization curves reveal high saturation magnetization of 0.8 muB per formula unit and high coercivity of 1.1 T, as well as a strong magnetic anisotropy.Comment: accepted for publicatio

Symplectic Symmetry of the Neutrino Mass and the See-Saw Mechanism

We investigate the algebraic structure of the most general neutrino mass Hamiltonian and place the see-saw mechanism in an algebraic framework. We show that this Hamiltonian can be written in terms of the generators of an Sp(4) algebra. The Pauli-Gursey transformation is an SU(2) rotation which is embedded in this Sp(4) group. This SU(2) also generates the see-saw mechanism.Comment: 11 pages, REVTE

An Algorithm for constructing Hjelmslev planes

Projective Hjelmslev planes and Affine Hjelmselv planes are generalisations of projective planes and affine planes. We present an algorithm for constructing a projective Hjelmslev planes and affine Hjelsmelv planes using projective planes, affine planes and orthogonal arrays. We show that all 2-uniform projective Hjelmslev planes, and all 2-uniform affine Hjelsmelv planes can be constructed in this way. As a corollary it is shown that all 2-uniform Affine Hjelmselv planes are sub-geometries of 2-uniform projective Hjelmselv planes.Comment: 15 pages. Algebraic Design Theory and Hadamard matrices, 2014, Springer Proceedings in Mathematics & Statistics 13