Formation of paired phases of bosons and their excitations in square lattice

We investigate the formation of paired states of bosons in an optical lattice, namely, pair superfluid (PSF) and pair supersolid (PSS) in the presence of pair hopping as well as the next nearest neighbor (NNN) interaction mimicking long-range forces. Both the zero and finite temperature phase diagrams are obtained using the cluster mean field theory, which includes the effect of correlations systematically. We also compute the low-energy excitations which capture the characteristic features of such paired states and their transitions. Apart from the gapless sound mode due to the PSF order, a gapped mode also appears in the PSF phase, similar to the Higgs mode of the usual atomic superfluid (ASF). The PSF to ASF transition exhibits an intriguing behavior due to the existence of a `tri-critical' point, where the nature of transition changes. As a consequence of the continuous PSF-ASF transition, the gapped mode of both the phases becomes gapless at the critical point. For sufficiently strong NNN interaction strength, a PSS phase appears with coexisting pair superfluidity and stripe density order. The softening of the roton mode as a precursor of density ordering and the appearance of a low-energy gapped mode serve as robust features related to the formation of the PSS phase. We also investigate the melting of PSF and PSS phases to normal fluid at finite temperatures, particularly the melting pathway of PSS which occurs in atleast two steps due to the coexisting orders. Finally, we discuss the possibility of emulating such exotic phases in the ongoing cold atom experiments

Steady state, relaxation and first-passage properties of a run-and-tumble particle in one-dimension

We investigate the motion of a run-and-tumble particle (RTP) in one dimension. We find the exact probability distribution of the particle with and without diffusion on the infinite line, as well as in a finite interval. In the infinite domain, this probability distribution approaches a Gaussian form in the long-time limit, as in the case of a regular Brownian particle. At intermediate times, this distribution exhibits unexpected multi-modal forms. In a finite domain, the probability distribution reaches a steady state form with peaks at the boundaries, in contrast to a Brownian particle. We also study the relaxation to the steady state analytically. Finally we compute the survival probability of the RTP in a semi-infinite domain. In the finite interval, we compute the exit probability and the associated exit times. We provide numerical verifications of our analytical results

Knowledge and awareness of emergency contraception among women undergoing medical termination of pregnancy in a tertiary care hospital in Andaman and Nicobar Islands

Background: Emergency contraception (EC) is a safe and cost effective measure, which when used judiciously can avoid unintended pregnancies. This is especially relevant in our country where both population control and unsafe abortions are a serious concern. For any contraceptive to be effective, the general population must have a proper knowledge and a positive attitude towards it. Women who come for medical termination of unwanted pregnancy are the best representatives of this and our study aimed to assess the knowledge and awareness of EC in this group.Methods: It was a descriptive, cross-sectional study conducted using a predesigned questionnaire among 100 women who came for medical termination of pregnancy at G. B. Pant Hospital, Port Blair. Questions were asked to evaluate their awareness, knowledge and attitude towards EC.Results: Out of 100 women, only 26 % had heard about EC, mostly from mass media, and seven of these 26 women had correct knowledge of timing of using EC. Four women had used EC before, whereas among others, fear of menstrual irregularity was the major deterrent. A significant association was found between education level and occupation with knowledge of EC.Conclusions: Although EC is a potent tool to avoid unwanted pregnancies, ignorance and misconceptions regarding EC is unfortunately still prevalent among those who would benefit the most from it. Medical personnel and health workers should be more proactive to propagate benefits of EC and encourage its use, as they are usually the first point of contact to the target population

Retinal photoisomerization versus counterion protonation in light and dark-adapted bacteriorhodopsin and its primary photoproduct

Discovered over 50 years ago, bacteriorhodopsin is the first recognized and most widely studied microbial retinal protein. Serving as a light-activated proton pump, it represents the archetypal ion-pumping system. Here we compare the photochemical dynamics of bacteriorhodopsin light and dark-adapted forms with that of the first metastable photocycle intermediate known as “K”. We observe that following thermal double isomerization of retinal in the dark from bio-active all-trans 15-anti to 13-cis, 15-syn, photochemistry proceeds even faster than the ~0.5 ps decay of the former, exhibiting ballistic wave packet curve crossing to the ground state. In contrast, photoexcitation of K containing a 13-cis, 15-anti chromophore leads to markedly multi-exponential excited state decay including much slower stages. QM/MM calculations, aimed to interpret these results, highlight the crucial role of protonation, showing that the classic quadrupole counterion model poorly reproduces spectral data and dynamics. Single protonation of ASP212 rectifies discrepancies and predicts triple ground state structural heterogeneity aligning with experimental observations. These findings prompt a reevaluation of counter ion protonation in bacteriorhodopsin and contribute to the broader understanding of its photochemical dynamics

Source apportionment and health risk assessment of nitrate in foothill aquifers of Western Ghats, South India

The present research reports the level of nitrate (NO3-), associated health risks and possible sources of contamination in groundwater from south India. Many samples (32%) are above or approaching the recommended level of NO3- for safe drinking water. The correlation analysis indicates different sources of NO3- contamination in different regions rather than a common origin. The isotopic measurements provide information about potential nitrogen sources contributing NO3- to the groundwater. Based on isotope analysis, the sources of NO3- in the groundwater of this region are likely to be from (a) septic sewage (b) organic nitrogen (animal and livestock excreta) (c) sewage (domestic & chemical fertilizers). Among the sample analyzed sewage, manure and septic sewage contribute 46%, 23% and 31% NO3- to groundwater. The HQ \u3e 1 indicates non-carcinogenic health risk due to consumption of high NO3- in drinking water. Among the studied age groups, infants are exposed to higher risk than children and adults. Results indicate that groundwater of this region is polluted with NO3- due to anthropogenic activities. Continuous consumption of such water may pose serious health risk to the residents

Detection, occurrence, and fate of emerging contaminants in agricultural environments (2019)

A review of 82 papers published in 2018 is presented. The topics ranged from detailed descriptions of analytical methods, to fate and occurrence studies, to ecological effects and sampling techniques for a wide variety of emerging contaminants likely to occur in agricultural environments. New methods and studies on veterinary pharmaceuticals, microplastics, and engineered nanomaterials in agricultural environments continue to expand our knowledge base on the occurrence and potential impacts of these compounds. This review is divided into the following sections: Introduction, Analytical Methods, Fate and Occurrence, Pharmaceutical Metabolites, Anthelmintics, Microplastics, and Engineered Nanomaterials

Enhancing the Stretchability of Two-Dimensional Materials through Kirigami: A Molecular Dynamics Study on Tungsten Disulfide

In recent years, the 'kirigami' technique has gained significant attention for creating meta-structures and meta-materials with exceptional characteristics, such as unprecedented stretchability. These properties, not typically inherent in the original materials or structures, present new opportunities for applications in stretchable electronics and photovoltaics. However, despite its scientific and practical significance, the application of kirigami patterning on a monolayer of tungsten disulfide (WS2), a van der Waals material with exceptional mechanical, electronic, and optical properties, has remained unexplored. This study utilizes molecular dynamics (MD) simulations to investigate the mechanical properties of monolayer WS2 with rectangular kirigami cuts. We find that, under tensile loading, the WS2 based kirigami structure exhibits a notable increase in tensile strain and a decrease in strength, thus demonstrating the effectiveness of the kirigami cutting technique in enhancing the stretchability of monolayer WS2. Additionally, increasing the overlap ratio enhances the stretchability of the structure, allowing for tailored high strength or high strain requirements. Furthermore, our observations reveal that increasing the density of cuts and reducing the length-to-width ratio of the kirigami nanosheet further improve the fracture strain, thereby enhancing the overall stretchability of the proposed kirigami patterned structure of WS2.Comment: 19 pages, 5 figure

A study to compare the efficacy of intermittent versus continuous regimen of pantaprazole in the management of upper gastrointestinal bleed (non variceal)

Background: UGI bleeding is defined as bleeding that occurs in the digestive tract proximal to the ligament of treitz. Intermittent dosage regimen IV bolus and high dose IV continuous infusion forms helps in achieving and maintaining this pH goal of more than 6 which forms optimal environment for peptic ulcer healing and clot stabilization to occur. Theoretically, high-dose IV continuous infusion should provide the most potent acid suppression. Aims and objective was to compare the efficacy of intermittent dose of pantoprazole given for 3 days i.e. 40mg intravenous twice a day versus continuous infusion dose of pantaprazole i.e. 80mg intravenous bolus followed by 8mg/hour for first 72hours in the treatment of UGI bleed.Methods: Patients of UGI bleed were randomly assigned to receive either continuous or intermittent regimen of pantaprazole as a part of management.Results: Among 118 patients of peptic ulcer disease, 7 patients had rebleed and 111 patients had no rebleed.3 patients among 59 patients who received continuous regimen and 4 patients among 59 patients who received intermittent regimen had rebleed with a total of 7 patients among 118 patients. Among 118 patients only 2 patients of the total had need for surgery for stabilization. Among 59 patients who received continuous regimen 2 patients needed surgery while none of the 59 patients who received intermittent regimen needed for surgery. Of the 118 patients 10 patients had mortality at the end of 30 day period. In both the regimes 5 patients died.Conclusions: The difference between Rockall score of the intermittent and continuous regimen group was statistically insignificant. The incidence of rebleed was 5.1 % for continuous and 6.7% for intermittent regimen which was statiscally insignificant. The incidence of mortality was similar 8.5%in both regimen