Visualization of Dimensional Effects in Collective Excitations of Optically Trapped Quasi-Two-Dimensional Bose Gases

We analyze the macroscopic dynamics of a Bose gas axially confined in an optical lattice with a superimposed harmonic trap, taking into account weak tunneling effect. Our results show that upon transition to the quasi-two-dimensional (2D) regime of the trapped gas, the 3D equation of state and equilibrium density profile acquire corrections from 2D many-body effects. The corresponding frequency shift in the transverse breathing mode is accessible within current facilities, suggesting a direct observation of dimensional effects. Comparisons with other relevant effects are also presented.Comment: 4 pages, 1 figur

Effects of disorder on quantum fluctuations and superfluid density of a Bose-Einstein condensate in a two-dimensional optical lattice

We investigate a Bose-Einstein condensate trapped in a 2D optical lattice in the presence of weak disorder within the framework of the Bogoliubov theory. In particular, we analyze the combined effects of disorder and an optical lattice on quantum fluctuations and superfluid density of the BEC system. Accordingly, the analytical expressions of the ground state energy and quantum depletion of the system are obtained. Our results show that the lattice still induces a characteristic 3D to 1D crossover in the behavior of quantum fluctuations, despite the presence of weak disorder. Furthermore, we use the linear response theory to calculate the normal fluid density of the condensate induced by disorder. Our results in the 3D regime show that the combined presence of disorder and lattice induce a normal fluid density that asymptotically approaches 4/3 of the corresponding condensate depletion. Conditions for possible experimental realization of our scenario are also proposed.Comment: 8 pages, 0 figure. To appear in Physical Review

Optically trapped quasi-two-dimensional Bose gases in random environment: quantum fluctuations and superfluid density

We investigate a dilute Bose gas confined in a tight one-dimensional (1D) optical lattice plus a superimposed random potential at zero temperature. Accordingly, the ground state energy, quantum depletion and superfluid density are calculated. The presence of the lattice introduces a crossover to the quasi-2D regime, where we analyze asymptotically the 2D behavior of the system, particularly the effects of disorder. We thereby offer an analytical expression for the ground state energy of a purely 2D Bose gas in a random potential. The obtained disorder-induced normal fluid density $n_n$ and quantum depletion $n_d$ both exhibit a characteristic $1/\ln\left(1/n_{2D}a_{2D}^{2}\right)$ dependence. Their ratio $n_n/n_d$ increases to $2$ compared to the familiar $4/3$ in lattice-free 3D geometry, signifying a more pronounced contrast between superfluidity and Bose-Einstein condensation in low dimensions. Conditions for possible experimental realization of our scenario are also proposed.Comment: 8 pages, 2 figure

Comparing knowledge, accessibility, and use of evidence-based chronic disease prevention processes across four countries

<p>Background: Evidence-based chronic disease prevention (EBCDP) effectively reduces incidence rates of many chronic diseases, but contextual factors influence the implementation of EBCDP worldwide. This study aims to examine the following contextual factors across four countries: knowledge, access, and use of chronic disease prevention processes.</p><p>Methods: In this cross-sectional study, public health practitioners (N = 400) from Australia (n = 121), Brazil (n = 76), China (n = 102), and the United States (n = 101) completed a 26-question survey on EBCDP. One-way ANOVA and Pearson's Chi-Square tests were used to assess differences in contextual factors of interest by country.</p><p>Results: Practitioners in China reported less knowledge of EBCDP processes (p < 0.001) and less use of repositories of evidence-based interventions, than those from other countries (p < 0.001). Academic journals were the most frequently used method for accessing information about evidence-based interventions across countries. When selecting interventions, Brazilian and Chinese practitioners were more likely to consider implementation ease while the Australian and United States practitioners were more likely to consider effectiveness (p < 0.001).</p><p>Conclusions: These findings can help inform and improve within and across country strategies for implementing EBCDP interventions.</p

Developing a survey tool to assess implementation of evidence-based chronic disease prevention in public health settings across four countries

201909 bcrcVersion of RecordPublishe

Probiotic-Based bacteriocin: Immunity supplementation against viruses. An updated review

Viral infections are a major cause of severe, fatal diseases worldwide. Recently, these infections have increased due to demanding contextual circumstances, such as environmental changes, increased migration of people and product distribution, rapid demographic changes, and outbreaks of novel viruses, including the COVID-19 outbreak. Internal variables that influence viral immunity have received attention along with these external causes to avert such novel viral outbreaks. The gastrointestinal microbiome (GIM), particularly the present probiotics, plays a vital role in the host immune system by mediating host protective immunity and acting as an immune regulator. Bacteriocins possess numerous health benefits and exhibit antagonistic activity against enteric pathogens and immunobiotics, thereby inhibiting viral infections. Moreover, disrupting the homeostasis of the GIM/host immune system negatively affects viral immunity. The interactions between bacteriocins and infectious viruses, particularly in COVID-19, through improved host immunity and physiology are complex and have not yet been studied, although several studies have proven that bacteriocins influence the outcomes of viral infections. However, the complex transmission to the affected sites and siRNA defense against nuclease digestion lead to challenging clinical trials. Additionally, bacteriocins are well known for their biofunctional properties and underlying mechanisms in the treatment of bacterial and fungal infections. However, few studies have shown the role of probiotics-derived bacteriocin against viral infections. Thus, based on the results of the previous studies, this review lays out a road map for future studies on bacteriocins for treating viral infections