The Relevant Operators for the Hubbard Hamiltonian with a magnetic field term

The Hubbard Hamiltonian and its variants/generalizations continue to dominate the theoretical modelling of important problems such as high temperature superconductivity. In this note we identify the set of relevant operators for the Hubbard Hamiltonian with a magnetic field term.Comment: 19 pages, RevTe

Low-energy, planar magnetic defects in BaFe2As2: nanotwins, twins, antiphase and domain boundaries

In BaFe2As2, structural and magnetic planar defects begin to proliferate below the structural phase transition, affecting descriptions of magnetism and superconductivity. We study using density-functional theory the stability and magnetic properties of competing antiphase and domain boundaries, twins and isolated $nano$twins (twin nuclei) - spin excitations proposed and/or observed. These nanoscale defects have very low surface energy ($22$-$210$~$m$Jm$^{-2}$), with twins favorable to the mesoscale. Defects exhibit smaller moments confined near their boundaries -- making a uniform-moment picture inappropriate for long-range magnetic order in real samples. {\it{Nano}}twins explain features in measured pair distribution functions, so should be considered when analyzing scattering data. All these defects can be weakly mobile and/or have fluctuations that lower assessed "ordered" moments from longer spatial and/or time averaging, and should be considered directly.Comment: 6 pages, 6 figures, 1 tabl

AN OVERALL VIEW ON GEMSTONE MINING IN GILGIT-BALTISTAN: PROBLEMS AND MITIGATIONS

Gilgit-Baltistan has tremendous amount of gemstone wealth and thousands of miners are busy to explore this wealth, but due to unscientific and crude mining methods this mineral wealth goes into waste in many ways, like fractures, damages and total destructions of gemstone due to ill blasting methods and lack of proper training. Gemstone mining is done in all districts of Gilgit-Baltistan. According to a careful survey in July 2007, 32 types of Gemstones (Precious and Semiprecious) are found in GB, out of total production of gemstones produced in Pakistan 95% come from GB. According to this survey there are more than 2000 mines which produce different variety of gemstones and numbers of miners involved in this mining industry directly or indirectly are more than 25000.  Due to these crude and unscientific mining methods, improper camps without hygienic facilities, lack of proper mining equipment, lack of basic health facilities and safety tools and lack of mining equipment repairing facilities at mining sites, number of problems are arising. These problems include damage to the fauna and flora in mining areas, damage to the eco system due to blasting and flow of people; mountains are becoming vulnerable due to improper mines development, glaciers melting due to use of thermal generators, spreading of human filth and waste like plastic and at last polluting of the water. This research is based on the mitigation of all these problems to some extent. The damage to the fauna and flora may be reduced by controlling spreading of human filth and waste, controlled blasting may be done by using modern blasting techniques, proper mines of international standard may be developed by enforcing the mining rules, use of thermal generators may be prohibited by developing small hydro projects at sites and at last pollution of water may be controlled by training people to adopt the cleanliness drives time to time and equipment repairing facilities at sites as well.  &nbsp

Renormalization group summation and analytic continuation from spacelike to timeline regions

Analytic continuation of the perturbative series from spacelike to timelike regions is performed using renormalization group summed perturbation theory (RGSPT). This method provides an all-order summation of kinematic ``$\pi^2$-terms'' accessible from a given order of a perturbative series. The impact of the summation of these terms is studied for Higgs boson decay and electromagnetic R-ratio in the perturbative QCD. Results obtained using RGSPT have improved convergence behavior in addition to significantly reduced renormalization scale dependence compared to fixed-order perturbation theory (FOPT). The higher-order behavior using the Pad\'e approximant is also studied for processes considered.Comment: 25 pages and 10 figure

Renormalization Group Improvement and QCD Sum Rules

We summarize the results obtained for the quark masses (u,d,s,c, and b) in Refs.~\cite{AlamKhan:2023ili,AlamKhan:2023kgs} and strong coupling ($\alpha_s$) using renormalization group (RG) improvement of the theoretical expressions and experimental inputs that enter in the QCD sum rules. We obtain $m_{u}(2 GeV)=2.00_{-0.40}^{+0.33}$ MeV, $m_{d}(2 GeV)=4.21_{-0.45}^{+0.48}$ MeV, and $m_{s}(2 GeV)=104.34_{-4.24}^{+4.32}$ MeV using Borel Laplace sum rules for the divergence of the axial vector currents. The relativistic sum rules for the moments of the heavy quark currents lead to the determination of $\alpha_s(M_Z)=0.1171(7)$, $\overline{m}_{c}=1281.1(3.8)$ MeV and $\overline{m}_{b}=4174.3(9.5)$ MeV.Comment: 10 Pages, 10 figures, and updated references. Based on the talk given at the 26th International Conference in HEP (QCD23), 10-14th July 2023, Montpellier-F

Renormalization Group Summation at High Orders and Implications to the Determination of Some Standard Model Parameters

We use renormalization group summed perturbation theory (RGSPT) to improve perturbation series in quantum chromodynamics in the determination of some of the standard model parameters.Comment: PhD Thesi

Renormalization group improved determination of light quark masses from Borel-Laplace sum rules

We determine masses of light quarks ($m_u$,$m_d$,$m_s$) using Borel-Laplace sum rules and renormalization group summed perturbation theory (RGSPT) from the divergence of the axial vector current. The RGSPT significantly reduces the scale dependence of the finite order perturbative series for the renormalization group (RG) invariant quantities such as spectral function, the second derivative of the polarization function of the pseudoscalar current correlator, and its Borel transformation. In addition, the convergence of the spectral function is significantly improved by summing all running logarithms and kinematical $\pi^2$-terms. Using RGSPT, we find m_s(2 GeV)=104.34_{-4.21}^{+4.23}\hs\MeV, and m_d(2 GeV)=4.21_{-0.45}^{+0.48}\hs\MeV leading to m_u(2 GeV)=2.00_{-0.40}^{+0.33}\hs\MeV.Comment: 17 pages and 8 figure

Allozyme and morphological variation in four hatchery stocks of Thai pangas, Pangasius hypophthalmus in Mymensingh, Bangladesh

Genetic and morphological characters of four hatchery population (Shambhuganj, Brahmaputra, Anudan and Bhai-Bhai) of Thai pangas, Pangasius hypophthalmus in Mymensingh region of Bangladesh was studied using morphological characters and allozyme markers from 29 November 2001 to 29 November 2002. A total of 14 morphometric and 6 meristic characters were verified, among which 3 morphometric (BDA, PELFL and HW) and 2 meristic characters (AFR, CFR) of Anudan hatchery population were found to be significantly higher (p>0.001) than those of the other three hatchery populations. Brahmaputra hatchery population was also significantly higher in two meristic characters (PCFR and CFR). For allozyme electrophoresis nine enzyme markers were used viz.: Esr-1*, G3pdh-2*, Gpi-1*, Gpi-2*, Ldh-1*, Ldh-2*, Mdh-1*, Mdh-2* and Pgm* where three loci (Esr-1*, Gpi-2* and Pgm*) were polymorphic (p>0.95) in Anudan and Brahmaputra hatchery populations. The mean proportion of polymorphic loci per population was higher (33.3%) in Brahmaputra and Anudan hatchery populations. Also the expected heterozygosity levels were 0.149 and 0.177 in Brahmaputra and Anudan hatchery populations, respectively. Based on Nei's (1972) genetic distances, the UPGMA dendrogram grouped the populations into two clusters. The Brahmaputra and Anudan populations are in one group; Shambhuganj, and Bhai-Bhai populations are in the second group. High genetic variation in Thai pangas was observed in the Brahmaputra and Anudan hatchery populations and less variation in the other two hatchery populations

Synthesis, characterization and urease inhibitory activities of Zn(II) complexes bearing C1-symmetric ligands derived from (R)-phenylethanamine

ABSTRACT. A series of Zn(II) complexes, supported with N-substituted phenylethanamine derivatives, [LnZnCl2] (where Ln = LA ((R)-1-phenyl-N-(thiophene-2-ylmethyl)ethanamine; LB (R)-N-(5-meyhylthiophene-2-yl)methyl-1-phenylethanamine; LC ((R)-N-(furan-2-ylmeththyl)-1-phenylethanamine and LD (R)-N-((5-methylfuran-2-yl)methyl)-1-phenylethanamine) were synthesized and characterized. The urease inhibitory activities of these complexes were determined against selected urease inhibitors where [LBZnCl2] was found to be the most prominent inhibitor of Jack bean urease (J. B. urease) (IC50 = 10.39±0.78 μM), whereas the activity of Bacillus pasteurii urease (B. P. urease) was predominantly inhibited by [LAZnCl2] (IC50 = 8.68±0.7 μM). Additionally, MOE-Dock program was used to affirm the probable binding modes of these complexes into the crystal structure of J. B. urease which certainly verified the inhibitory mechanism of these novel complexes.                     KEY WORDS: Zn(II) complexes, (R)-Phenylethanamine, Urease inhibition, Molecular docking   Bull. Chem. Soc. Ethiop. 2021, 35(2), 301-314. DOI: https://dx.doi.org/10.4314/bcse.v35i2.