Impacts of land-use change and urban development on carbon sequestration in tropical seagrass meadow sediments.

Seagrass meadows store significant carbon stocks at a global scale, but land-use change and other anthropogenic activities can alter the natural process of organic carbon (Corg) accumulation. Here, we assessed the carbon accumulation history of two seagrass meadows in Zanzibar (Tanzania) that have experienced different degrees of disturbance. The meadow at Stone Town has been highly exposed to urban development during the 20th century, while the Mbweni meadow is located in an area with relatively low impacts but historical clearing of adjacent mangroves. The results showed that the two sites had similar sedimentary Corg accumulation rates (22-25 g m-2 yr-1) since the 1940s, while during the last two decades (∼1998 until 2018) they exhibited 24-30% higher accumulation of Corg, which was linked to shifts in Corg sources. The increase in the δ13C isotopic signature of sedimentary Corg (towards a higher seagrass contribution) at the Stone Town site since 1998 points to improved seagrass meadow conditions and Corg accumulation capacity of the meadow after the relocation of a major sewage outlet in the mid-1990s. In contrast, the decrease in the δ13C signatures of sedimentary Corg in the Mbweni meadow since the early 2010s was likely linked to increased Corg run-off of mangrove/terrestrial material following mangrove deforestation. This study exemplifies two different pathways by which land-based human activities can alter the carbon storage capacity of seagrass meadows (i.e. sewage waste management and mangrove deforestation) and showcases opportunities for management of vegetated coastal Corg sinks.

Hybrid Tool for Assessment of Professionalism among Dental Undergraduate Students.

CONTEXT: Of the several methods available for assessment of professionalism, there is still no consensus on an ideal tool for dental undergraduate (UG) students. AIMS: The study aims to use a hybrid tool for assessment of professionalism among dental undergraduate students. SETTINGS AND DESIGN: Cross-sectional design with purposive sampling. SUBJECTS AND METHODS: All final year UG dental students participated in this study. Evaluation of knowledge about professionalism was through written test. Professional behavior of each final year student in a clinical setting was assessed with a prevalidated questionnaire of multisource feedback (MSF). The scores of written test and the MSF were calculated for each student. Data were analyzed to evaluate scores of knowledge and MSF scores as per assessor category. Correlation between knowledge scores and MSF was evaluated. Student perceptions were taken toward assessment of professionalism. STATISTICAL ANALYSIS USED: Statistical analysis was done using descriptive statistics. Pearson's coefficient was used to determine the correlation between average knowledge scores and the MSF scores. RESULTS: Knowledge scores were significantly more for female students (P < 0.05, t-test). Patients rated the students highest. Correlation between knowledge and MSF scores was found to be statistically significant (Pearson's correlation, P < 0.01). Students gave feedback that assessment of professionalism should be done from the beginning of the clinical years. CONCLUSIONS: Evaluation revealed that knowledge toward professionalism correlated with the professional behavior implying association between knowledge and reasons for a particular action.

The impact of chimerism in DNA-based forensic sex determination analysis.

Sex determination is the most important step in personal identification in forensic investigations. DNA-based sex determination analysis is comparatively more reliable than the other conventional methods of sex determination analysis. Advanced technology like real-time polymerase chain reaction (PCR) offers accurate and reproducible results and is at the level of legal acceptance. But still there are situations like chimerism where an individual possess both male and female specific factors together in their body. Sex determination analysis in such cases can give erroneous results. This paper discusses the phenomenon of chimerism and its impact on sex determination analysis in forensic investigations.