Berry phase of the composite-fermion Fermi Sea: Effect of Landau-level mixing

We construct explicit lowest-Landau-level wave functions for the composite-fermion Fermi sea and its low energy excitations following a recently developed approach [Pu, Wu and Jain, Phys. Rev. B 96, 195302 (2018)] and demonstrate them to be very accurate representations of the Coulomb eigenstates. We further ask how the Berry phase associated with a closed loop around the Fermi circle, predicted to be $\pi$ in a Dirac composite fermion theory satisfying particle-hole symmetry [D. T. Son, Phys. Rev. X 5, 031027 (2015)], is affected by Landau level mixing. For this purpose, we consider a simple model wherein we determine the variational ground state as a function of Landau level mixing within the space spanned by two basis functions: the lowest-Landau-level projected and the unprojected composite-fermion Fermi sea wave functions. We evaluate Berry phase for a path around the Fermi circle within this model following a recent prescription, and find that it rotates rapidly as a function of Landau level mixing. We also consider the effect of a particle-hole symmetry breaking three-body interaction on the Berry phase while confining the Hilbert space to the lowest Landau level. Our study deepens the connection between the $\pi$ Berry phase and the exact particle-hole symmetry in the lowest Landau level.Comment: 13 pages, 6 figure

Optimization of alkaline protease production from Pseudomonas fluorescens isolated from meat waste contaminated soil

A protease producing bacteria was isolated from meat waste contaminated soil and identified as Pseudomonas fluorescens. Optimization of the fermentation medium for maximum protease production was carried out. The culture conditions like inoculum concentration, incubation time, pH, temperature, carbon sources, nitrogen sources and metal ions were optimized. The optimum conditions found for protease production was 37°C at pH 9, with 2% inoculum in the medium for 24 h. Wheat bran and peptone stimulates the production of protease. Magnesium sulphate has less inhibitory effect among the metal ions tested

Flaws in the Current Building Code and Code Making Process in Kenya

For safe, decent and affordable housing, a proper code of practice is vital. A proper building code of practice should enhance growth, regulate and revolutionize housing sector and utilization of the available local materials without limitations.  As the stakeholders are revising and reviewing the code of practice and administration of many counties prepare to take the initiative of executing the code, various aspects concerning it should not be overlooked. The current housing and infrastructure policies and adaptive by-laws have led to calamities and epidemics being reported all over.  Poor planning, administrative procedures and inadequate enforcement strategies are a few challenges facing the current building code in Kenya. This paper discusses the various flaws that are observed in the current code of practice. As the building sector is preparing to acknowledge, implement and adopt KScode 2009; emphasis has been put on description of various principles concerning code development, adopting and implementation processes. This paper may also act as a guideline for currently concerned bodies revising the code of practice. Provisions of minimum standards, safety of lives, health and security of one’s property should be emphasized in any code of practice used. Keywords: building code, flaws, implementation, materials, planning, building