Role of Te in the low dimensional multiferroic material FeTe2O5Br

Using first principles density functional calculations, we study the electronic structure of the low-dimensional multiferroic compound FeTe2O5Br to investigate the origin of the magnetoelectric (ME) effect and the role of Te ions in this system. We find that without magnetism even in the presence of Te-5s lone pairs, the system remains centrosymmetric due to the antipolar orientation of the lone pairs. Our study shows that the exchange striction within the Fe tetramers as well as between them is responsible for the ME effect in FeTe2O5Br. We also find that the Te^4+ ions play an important role in the inter-tetramer exchange striction as well as contribute to the electric polarization in FeTe2O5Br, once the polarization is triggered by the magnetic ordering.Comment: 8 pages, 8 figures, Journal version: http://link.aps.org/doi/10.1103/PhysRevB.88.09440

Advocate Asaduzzaman Siddqui v. Bangladesh: Bangladesh's Dilemma with Judges' Impeachment

Like the major constitutional systems of the world, Bangladesh had a parliamentary removal process for the judges of the highest court. The system was however changed by the military rulers of late 1970s. Very recently, the parliament of Bangladesh attempted to revive the original system and the Sixteenth Amendment to the Constitution of Bangladesh, was passed in 2014. The case at hand, Asaduzzaman Siddiqui v. Bangladesh is a challenge to this Amendment. This casecomment analyzes the arguments and reasoning of the case and argues that the judges and counsels concerned have wasted a chance to analyze this Amendment from its proper perspective. Therefore, a very high profile constitutional litigation ended in adding virtually nothing to the constitutional jurisprudence of Bangladesh

Comparative economic analysis of pond fish production in Mymensingh and Jessore Districts, Bangladesh

The study was conducted to determine the cost, return and relative profitability of pond fish production of Mymensingh and Jessore districts. A total of 75 ponds were selected on the basis of purposive random sampling technique from 7 villages under 2 Upazila (Trishal and Gouripur) of Mymensingh districts and 8 villages under 4 Upazila (Monimmpur, Jhikorgacha, Chowgacha and Sadar) of Jessore district. It was found that per hectare per year gross cost of pond fish production in Mymensingh and Jessore were Tk 333457.75 and Tk 54327.74, while gross return were Tk 434131.16 and Tk. 96640.00 and net return were Tk 100673.41 and Tk. 42312.26, respectively. The findings of this study revealed that the pond fish production in Jessore district was more profitable than that of Mymensingh district. Cobb-Douglas production function was applied to realize the specific effect of the factors on pond fish production. Out of six variables included in the function three variables had positive impact on return from pond fish production, in Mymensingh district but five variables had positive impact on return from pond fish production in Jessore distric

TORCH infection in antenatal women: A 5-year hospital-based study

Objectives: The diagnosis of acute TORCH infection in pregnant women being pertinent for the management of such infections prompted the current study due to lack of published data from India describing the seroprevalence of specific IgM antibodies to TORCH agents in this part of Northern India. Material and Methods: Blood samples of a total of 240 high-risk pregnant women attending the antenatal clinic of our tertiary care hospital during a 5-year period (2005–2009) were analyzed for specific IgM antibodies to Toxoplasma gondii, rubella, Cytomegalovirus (CMV), and combined herpes simplex virus (HSV) 1 and 2 by capture enzyme-linked immunosorbent assay. Results: Overall, seropositivity to TORCH infection in the present study was 98.8%. Seropositivity to T. gondii was 24.2%, rubella 9.2%, CMV 53.8%, and 11.7% were positive for combined HSV-1 and 2 infections. The average age of the study population was 27.5 years. Overall, 15.4% of women were seropositive for coinfections. Conclusion: The high seropositivity of 98.8% and presence of multiple infections seen in the present study communicate to all health authorities to screen routinely all pregnant women for TORCH infections for appropriate intervention in the proper management of these patients

Co-Infection of HSV in Gonococcal Urethritis Patients

Co-infection with two different pathogens may alter the classical clinical course that manifests infection as single pathogen. In STIs, such co-infection may trigger the reactivation of a latent infection, and syndromic approach may not be insufficient to free the host of the entire gamut of infectivity agents. Present study analyzed appropriate samples for Neisseria gonorrheae and HSV from 200 patients presented to STI clinic. Gonorrhea was detected in 4% and HSV in 5% of patients. 25% of gonorrhea patients had HSV-2 co-infection with an overall 4.5% yield of subclinical HSV cases which would have been missed leading to inappropriate treatment, risk of recurrence and transmission to contacts. Awareness regarding encounter with multiple infections is necessary for effective management

Probing the strongly correlated magnetic state of Co2_2C nanoparticles at low temperatures using μ\muSR

Co$_2$C nanoparticles (NPs) are amongst transition metal carbides whose magnetic properties have not been well explored. A recent study by Nirmal Roy et al. [1] showed that a collection of Co$_2$C NPs exhibit an exchange bias (EB) effect below T$_{EB}$ = 50 K and also a spin glass (SG) state below T$_{SG}$ = 5 K. We use magnetic, electrical transport, specific heat, and muon spin rotation ($\mu$SR) measurements to explore further the magnetic properties of these NPs. We uncover the onset of Kondo localization at Kondo temperature T$_K$ (= 40.1 K), near the onset of EB effect. A crossover from the Kondo-screened scenario to an RKKY interaction-dominated regime is also observed for T < T$_K$. Specific heat measurements confirm Kondo localization and heavy fermionic nature in Co$_2$C at low T. At low T, zero field $\mu$SR spectra reveal a dominant magnetically disordered fraction with slow relaxation and a smaller fraction with short-range order exhibiting fast relaxation, with no evidence of long-range magnetic order. We observe an increase in this fast relaxation rate between T$_{EB}$ and T$_{SG}$, suggesting a slowing down of the fluctuating local magnetic environment around muons. Transverse field $\mu$SR spectra show the emergence of a stable, multi-peaked local magnetic field distribution below T$_{EB}$. Longitudinal field $\mu$SR spectra shows distinct changes in the dynamics of fluctuations suggesting the presence of a frozen glassy like state below 6 K. Our results suggest that below T$_{EB}$, Co$_2$C NPs pellet develops a magnetic interface, separating disordered and short-range order fractions. The Exchange interaction that sets in below T$_{EB}$ at the interface couples them and suppresses the fluctuations. With the suppression of magnetic fluctuations below T$_{EB}$, strong correlation effects in the electronic state of Co$_2$C lead to Kondo localization.Comment: 37 Pages, 11 Figure

Exploring Repetitive DNA Landscapes Using REPCLASS, a Tool That Automates the Classification of Transposable Elements in Eukaryotic Genomes

Eukaryotic genomes contain large amount of repetitive DNA, most of which is derived from transposable elements (TEs). Progress has been made to develop computational tools for ab initio identification of repeat families, but there is an urgent need to develop tools to automate the annotation of TEs in genome sequences. Here we introduce REPCLASS, a tool that automates the classification of TE sequences. Using control repeat libraries, we show that the program can classify accurately virtually any known TE types. Combining REPCLASS to ab initio repeat finding in the genomes of Caenorhabditis elegans and Drosophila melanogaster allowed us to recover the contrasting TE landscape characteristic of these species. Unexpectedly, REPCLASS also uncovered several novel TE families in both genomes, augmenting the TE repertoire of these model species. When applied to the genomes of distant Caenorhabditis and Drosophila species, the approach revealed a remarkable conservation of TE composition profile within each genus, despite substantial interspecific covariations in genome size and in the number of TEs and TE families. Lastly, we applied REPCLASS to analyze 10 fungal genomes from a wide taxonomic range, most of which have not been analyzed for TE content previously. The results showed that TE diversity varies widely across the fungi “kingdom” and appears to positively correlate with genome size, in particular for DNA transposons. Together, these data validate REPCLASS as a powerful tool to explore the repetitive DNA landscapes of eukaryotes and to shed light onto the evolutionary forces shaping TE diversity and genome architecture

o-Iminobenzosemiquinonate and o-Imino-p-methylbenzosemiquinonate Anion Radicals Coupled VO2þ Stabilization

The diamagnetic VO2þ-iminobenzosemiquinonate anion radical (LR IS •-, R = H, Me) complexes, (L-)(VO2þ)(LR IS •-): (L1 -)(VO2þ)(LH IS •-)•3/2MeOH (1•3/2MeOH), (L2 -)(VO2þ)(LH IS •-) (2), and (L2 -)(VO2þ)(LMe IS •-)•1/2 LMe AP (3•1/2 LMe AP), incorporating tridentate monoanionic NNO-donor ligands {L = L1 - or L2 -, L1H = (2-[(phenylpyridin-2-yl-methylene) amino]phenol; L2H = 1-(2-pyridylazo)-2-naphthol; LH IS •- = o-iminobenzosemiquinonate anion radical; LMe IS •- = o-imino-p-methylbenzosemiquinonate anion radical; and LMe AP = o-amino-p-methylphenol} have been isolated and characterized by elemental analyses, IR, mass,NMR, and UV-vis spectra, including the single-crystal X-ray structure determinations of 1•3/2MeOH and 3•1/2 LMe AP. Complexes 1•3/2MeOH, 2, and 3•1/2 LMe AP absorb strongly in the visible region because of intraligand (IL) and ligand-to-metal charge transfers (LMCT). 1•3/2MeOH is luminescent (λext, 333 nm; λem, 522, 553 nm) in frozen dichloromethane- toluene glass at 77 K due to πdiimine f πdiimine* transition. The V-Ophenolato (cis to the VdO) lengths, 1.940(2) and 1.984(2) Å, respectively, in 1•3/2MeOH and 3•1/2 LMe AP are consistent with the VO2þ description. The V-Oiminosemiquinonate (trans to the VdO) lengths, 2.1324(19) in 1•3/2MeOH and 2.083(2) Å in 3•1/2 LMe AP, are expectedly ∼0.20 Å longer due to the trans influence of the VdO bond. Because of the stronger affinity of the paramagnetic VO2þ ion to the LH IS •- or LMe IS •-, the VNiminosemiquinonate lengths, 1.908(2) and 1.921(2) Å, respectively, in 1•3/2MeOH and 3•1/2 LMe AP, are unexpectedly shorter. Density functional theory (DFT) calculations using B3LYP, B3PW91, and PBE1PBE functionals on 1 and 2 have established that the closed shell singlet (CSS) solutions (VO3þ-amidophenolato (LR AP 2-) coordination) of these complexes are unstable with respect to triplet perturbations. But BS (1,1)Ms = 0 (VO2þ-iminobenzosemiquinonate anion radical (LR IS •-) coordination) solutions of these species are stable and reproduce the experimental bond parameters well. Spin density distributions of one electron oxidized cations are consistent with the [(L-)(VO2þ)(LR IQ)]þ descriptions [VO2þ-o-iminobenzoquinone (LR IQ) coordination], and one electron reduced anions are consistent with the [(L•2-)(VO3þ)(LR AP 2-)]- descriptions [VO3þ-amidophenolato (LR AP 2-) coordination], incorporating the diimine anion radical (L1 •2-) or azo anion radical (L2 3-). Although, cations and anions are not isolable, but electro-and spectro-electrochemical experiments have shown that 3þ and 3- ions are more stable than 1þ, 2þ and 1-, 2- ions. In all cases, the reductions occur with simultaneous two electron transfer, may be due to formation of coupled diimine/azo anion radical- VO2þ species as in [(L•2-)(VO2þ)(LR AP 2-)]2