Sustainable shrimp farming in Sri Lanka; Utilization of BMPs and antibiotics use.

Objective: In the context of the fast-expanding shrimp farming industry in Sri Lanka, this study aimed to evaluate the distribution and understanding of BMPs, examine the relationship between BMPs and disease outbreaks, and analyze the current antibiotic usage trends through a fact-finding survey. Materials and Methods: A questionnaire survey was conducted in 131 shrimp farms located in Puttalam District in North Western Province, where shrimp farming is thriving in Sri Lanka. The survey was conducted from September to October 2021. In addition, in August 2022 and August 2023, interviews were conducted with shrimp farms in Puttalam district and Batticaloa district, shrimp hatcheries, and export companies. Data were analyzed using descriptive statistics, Probit, and Tobit regression analysis. Results: The item-count technique revealed a significant (p < 0.05) difference in the use of antibiotics without consulting experts, signifying inappropriate use. No aquaculture farmer reported being unaware of BMPs, and among the 45 farmers who attended a BMPs seminar, 30 claimed to possess a good understanding of BMPs. Probit and Tobit regression results revealed that the rate of understanding of BMPs, education level, and obtaining information on the sanitation management of shrimp farming from extension and guidance organizations were inversely associated with both disease incidence in shrimp farming and shrimp discards. Conclusion: Although the use of antibiotics is prohibited in BMPs, the analysis results suggest inappropriate use of antibiotics. The findings indicate that enhanced BMP understanding can reduce disease incidence and shrimp discards, emphasizing the need for incentives to promote BMP adoption and reduce the necessity for antibiotics.

Crystallization of polarons through charge and spin ordering transitions in 1T-TaS2.

The interaction of electrons with the lattice in metals can lead to reduction of their kinetic energy to the point where they may form heavy, dressed quasiparticles-polarons. Unfortunately, polaronic lattice distortions are difficult to distinguish from more conventional charge- and spin-ordering phenomena at low temperatures. Here we present a study of local symmetry breaking of the lattice structure on the picosecond timescale in the prototype layered dichalcogenide Mott insulator 1T-TaS2 using X-ray pair-distribution function measurements. We clearly identify symmetry-breaking polaronic lattice distortions at temperatures well above the ordered phases, and record the evolution of broken symmetry states from 915 K to 15 K. The data imply that charge ordering is driven by polaron crystallization into a Wigner crystal-like state, rather than Fermi surface nesting or conventional electron-phonon coupling. At intermediate temperatures the local lattice distortions are found to be consistent with a quantum spin liquid state.

Impacts of COVID-19 pandemic on the fisheries sector of Sri Lanka.

We empirically ascertained the impact of COVID-19 pandemic on fisheries sector of Sri Lanka, focusing on the year 2020 which helps identify changes in production and income of the sector. Daily wage and monthly income of stakeholders in the pre-pandemic period are well above the national minimum daily wage and monthly income of the workers in Sri Lanka. Defensive measures taken to curb rapid spread of COVID-19 have given a shock to all stakeholders of the sector. Health and safety measures imposed to avert the spreading of pandemic have compelled the stakeholders to incur extra costs. Study indicates significant impact of the pandemic on production and income of the stakeholders in the fisheries value chain. Comparison of total fish production during 2015-2020 confirms the impacts on the sector and, changes in fish production and income in 2020 completely coincide with COVID-19-time line. Severity of impacts is stakeholder and area specific. Fisheries districts in western province are highly impacted over the other districts. DPSIR framework captures the status of social system and unfolds existing problems in the sector, enabling decision-makers to take policy decisions for future actions. Government of Sri Lanka has taken several steps to revive the sector, and stakeholders have shown an adaptive capacity to cope with impacts of the pandemic. Present crisis in the sector is far from over and, short-term impacts are likely to be followed by long-term crises, thus measures should be taken to revive the sector in new normal conditions and the post-pandemic era.

Dual Orbital Degeneracy Lifting in a Strongly Correlated Electron System.

The local structure of NaTiSi_{2}O_{6} is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the transition. The analysis unravels that, on warming, the dimers evolve into a short range orbital degeneracy lifted (ODL) state of dual orbital character, persisting up to at least 490 K. The ODL state is correlated over the length scale spanning ∼6 sites of the Ti zigzag chains. Results imply that the ODL phenomenology extends to strongly correlated electron systems.

Local orbital degeneracy lifting as a precursor to an orbital-selective Peierls transition.

Fundamental electronic principles underlying all transition metal compounds are the symmetry and filling of the d-electron orbitals and the influence of this filling on structural configurations and responses. Here we use a sensitive local structural technique, x-ray atomic pair distribution function analysis, to reveal the presence of fluctuating local-structural distortions at high temperature in one such compound, CuIr2S4. We show that this hitherto overlooked fluctuating symmetry-lowering is electronic in origin and will modify the energy-level spectrum and electronic and magnetic properties. The explanation is a local, fluctuating, orbital-degeneracy-lifted state. The natural extension of our result would be that this phenomenon is likely to be widespread amongst diverse classes of partially filled nominally degenerate d-electron systems, with potentially broad implications for our understanding of their properties.