DYNAMIC SUPERALGEBRA AND SUPERSYMMETRY FOR A MANY-FERMION SYSTEM

A linearization scheme is proposed for the general Hamiltonian of an interacting fermion system, consisting of a mean-field approximation in which pairing and umklapp play dominant roles. A variety of models emerge, characterized by a hierarchy of spectrum-generating algebras and superalgebras, of which some are supersymmetric. The superconducting phase transition is shown to be related to supersymmetry breaking

ASSESSMENT OF SOME HEAVY METALS IN SOME CHOCOLATE BRANDS AND BREAD SOLD IN MAIDUGURI, BORNO STATE, NIGERIA

Three brands of chocolate and five varieties of bread samples were collected and subjected to acid digestion for evaluation of some heavy metals (Cu, Cr, Pb, Fe, Cd and Zn) using atomic absorption spectrophotometry. The concentrations of the studied heavy metals in the chocolate brands were in the range 0.02-0.20; 0.02-0.10 and 0.09-0.20 mg/kg for Cd, Zn and Cr respectively. whereas Pb was not detected in the study. As per the bread samples, the concentrations ranged 0.05-0.13; 0.60-2.24, 0.30-0.06 and 0.02-0.10 mg/kg for Cd, Zn, Cr and Pb respectively. This study indicates that the concentrations of the studied brands of chocolate and bread are within the allowable limits hence pose no potential health risk or hazard upon consumption. Keywords: Chocolate, Concentrations, Spectrometry, Acid digestio

Utilization of Airlift Fermenters in the Mass Propagation of Pseudomonas and AureobasidiumSpecies for the Bioremediation of Crude Oil Polluted Aquatic Environments

This study involved the design and fabrication of airlift fermenters for the mass propagation of a consortium of three microorganisms  (Pseudomonas aeruginosa, Pseudomonas fluorescence and Aureobasidium pullulans). The efficacy of the blend in the bioremediation of simulated crude oil polluted water systems environments was also tested with a view to generating more data on crude oil degrading microorganisms for bioremediation purposes. The organisms were separately grown on a gyratory shaker at 120 rpm and at 30 °C until notable growths were observed. Equal volume of the grown organisms (500 ml) of mixed culture was used as inoculum for the 4.5 L of medium in the 7 L airlift fermenter. Thereafter, this was transferred into the 45 litres medium in the 70 L fermenter until significant growth was observed at room temperature. Culture broths were withdrawn at intervals for the determination of biomass and residual hydrocarbon concentrations. The product from the 70 L fermenter was introduced into simulated polluted water systems from which samples were withdrawn weekly. Analyses for residual hydrocarbon contents were carried out using appropriate analytical techniques. The results showed that 78.5% hydrocarbon removal was observed in the 7 L fermenter after 72 h, while that of the 70 L fermenter was 97.8% after 180 h of fermentation. Polluted water sample treated with the microbes experienced 96.4% removal after 10 weeks of treatment. It was observed further that the application of NPK fertilizer biostimulant aided microbial activities in the removal of petroleum hydrocarbons than urea, cow dung and poultry droppings. The study has demonstrated that effective bioremediation of crude oil polluted water systems could be achieved through the application of biostimulants with mass propagated crude oil degrading organisms using airlift fermenter systems. Keywords: Pseudomonas aeruginosa; Pseudomonas fluorescence; Aureobasidium pullulans; Airlift fermenter; Bioremediation; Biostimulation; Bioaugmentation

Heisenberg–Weyl algebra revisited: Combinatorics of words and paths

The Heisenberg–Weyl algebra, which underlies virtually all physical representations of Quantum Theory, is considered from the combinatorial point of view. We provide a concrete model of the algebra in terms of paths on a lattice with some decomposition rules. We also discuss the rook problem on the associated Ferrers board; this is related to the calculus in the normally ordered basis. From this starting point we explore a combinatorial underpinning of the Heisenberg–Weyl algebra, which offers novel perspectives, methods and applications

Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model

We propose and investigate a model for the coexistence of Superconductivity (SC) and Ferroelectricity (FE) based on the dynamical symmetries $su(2)$ for the pseudo-spin SC sector, $h(4)$ for the displaced oscillator FE sector, and $su(2) \otimes h(4)$ for the composite system. We assume a minimal symmetry-allowed coupling, and simplify the hamiltonian using a double mean field approximation (DMFA). A variational coherent state (VCS) trial wave-function is used for the ground state: the energy, and the relevant order parameters for SC and FE are obtained. For positive sign of the SC-FE coupling coefficient, a non-zero value of either order parameter can suppress the other (FE polarization suppresses SC and vice versa). This gives some support to "Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive. For such a Ferroelectric Superconductor we predict: a) the SC gap $\Delta$ (and $T_c$) will increase with increasing applied pressure when pressure quenches FE as in many ferroelectrics, and b) the FE polarization will increase with increaesing magnetic field up to $H_c$. The last result is equivalent to the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE material. Some discussion will be given of the relation of these results to the cuprate superconductors.Comment: 46 page

Dobiński relations and ordering of boson operators

We introduce a generalization of the Dobiński relation, through which we define a family of Bell-type numbers and polynomials. Such generalized Dobiński relations are coherent state matrix elements of expressions involving boson ladder operators. This may be used in order to obtain normally ordered forms of polynomials in creation and annihilation operators, both if the latter satisfy canonical and deformed commutation relations

Spin-squeezed Ground States in the Bilayer Quantum Hall Ferromagnet

A "squeezed-vacuum" state considered in quantum optics is shown to be realized in the ground-state wavefunction for the bilayer quantum Hall system at the total Landau level filling of $\nu=1/m$ (m: odd integer). This is derived in the boson approximation, where a particle-hole pair creation across the symmetric-antisymmetric gap, $\Delta_{SAS}$, is regarded as a boson. In terms of the pseudospin describing the layers, the state is a spin-squeezed state, where the degree of squeezing is controlled by the layer separation and $\Delta_{SAS}$. An exciton condensation, which amounts to a rotated spin-squeezed state, has a higher energy due to the degraded SU(2) symmetry for $\Delta_{SAS} \neq 0$.Comment: 4 pages, revtex, one figure, to appear in PRB Rapid Communicatio

Seed dressing maize with imazapyr to control Striga hermonthica in farmers’ fields in the savannas of Nigeria

Open Access Journal; Published online: 17 Mar 2020Use of small doses of imazapyr and pyrithiobac for seed coatings of imazapyr-resistant maize hybrids (IR-Maize) offers an effective means to control Striga hermonthica. Field trials were conducted in Bauchi and Kano States of Nigeria in 2014 and 2015 under heavy Striga infestation to evaluate the potential effectiveness of herbicide coated hybrids maize on Striga control in farmers’ field. Results showed that herbicide coated seeds reduced number of emerged Striga per m2 and Striga damage symptoms in farmers’ fields in all the locations. In Kano the number of emerged Striga was 4.9 to 7.9 times less in herbicide treated hybrids in comparison with those of the same hybrids planted without herbicide treatment. The Striga-resistant open pollinated variety (OPV) (TZL COMP1 SYN) had 6.7 to 8.0 times more Striga than the treated hybrids. In Bauchi, the number of emerged Striga on the untreated IR-maize hybrids were over four-times higher on the treated IR-maize hybrids than on the untreated hybrids. The Striga-resistant OPV check had four-times more Striga than the treated IR-maize hybrids and twice more than the untreated IR-maize hybrids across the two years. However, the effects of herbicide seed coating on grain yields were not consistent because of strong seasonal effects. The result revealed that coating of imazapyr-resistant hybrid maize seeds with imazapyr was effective in reducing Striga infestation in farmers’ fields. Although herbicide seed coating did not give consistent yield advantages of the hybrids over the untreated checks, a combination of herbicide seed treatment and genetic resistance to Striga would serve as an effective integrated approach that could significantly reduce the parasite seed bank from the soil and prevent production of new seeds. The IR-hybrids and the OPV checks contained Striga resistance/tolerant genes that protected them against drastic yield loss in the Striga infested fields in both Bauchi and Kano

Parental Knowledge and Attitude of Adolescent Sexuality Education in Rural and Urban Communities of Ekiti State, Nigeria

Background: Parents play a key role in shaping the attitudes and behaviour of adolescents, thereby reducing risky sexual behaviour and promoting healthy sexual development. This study assessed and compared parental knowledge and attitude towards adolescent sexuality education (ASE) in rural and urban communities of Ekiti State, Nigeria.Materials and Methods: A comparative cross-sectional study of 800 parents (or guardians) of adolescents in selected rural and urban communities, recruited through a multi-stage sampling technique. An interviewer-administered semi-structured questionnaire was used to collect data. Data were analysed using SPSS version 20.Result: A significantly higher proportion of parents from the urban communities had a good knowledge of ASE (72.5% versus 66.0%, p-value 0.046). However, knowledge of safe sex and dating was low in both communities. About three-quarters of the respondents had a positive attitude towards ASE with no statistically significant difference in both rural and urban communities (p-value: 0.363).Conclusion: Parental knowledge of ASE is high in Ekiti State, and it is higher in the urban compared to the rural communities. Attitude towards ASE is high in both communities but not significantly different. However, the knowledge of the various components of ASE varies significantly amongst the communities. While it is recommended that government should create a supportive environment to assist parents in their roles as sexuality educators, parents should see sexuality education as their responsibility and also start the discussion early

Maize-soybean intercropping for sustainable intensification of cereal-legume cropping systems in northern Nigeria

Article purchased; Published online: 20 Nov 2017Field studies were conducted during the 2014 and 2015 wet seasons at Zaria in the northern Guinea savanna and at Iburu in the southern Guinea savanna of Nigeria to determine the productivity of maize– soybean intercropping system. There were four treatment combinations in the experiment: sole maize; sole soybean; maize spaced at 50 cm and intercropped with soybean; and maize spaced at 65 cm and intercropped with soybean. The experiment was laid out in a randomized complete block design with three replications. The results showed that sole cropped maize and soybean generally outperformed the intercropped component crops. Land Equivalent Ratio (LER) was greater than 1 for all the intercrop treatments, indicating that it is advantageous to grow maize and soybean in association than in pure stands. Except for 2014 in Zaria, LER for intercropped maize spaced at 50 cm was higher than that for maize spaced at 65 cm. Gross Monetary Value (GMV) was generally higher for intercrops than sole crops except in Iburu in 2015 where GMV for intercropped maize spaced at 65 cm was similar to those of sole maize and soybean. Monetary Advantage Index (MAI) was positive for all intercrop treatments in both locations and years, which shows definite yield and economic advantages compared to the sole cropping systems. This suggests that farmers can intercrop soybean and maize with maize spaced at 50 cm and 65 cm