The genus Drepanolejeunea (Spruce) Schiffn. (Lejeuneaceae; Marchantiophyta) in the Western Ghats with special reference to Kerala

Diversity of the genus Drepanolejeunea (Spruce) Schiffn. of the family Lejeuneaceae in Kerala is discussed in detail. So far, 8 species have been reported from the Western Ghats, of which 6 occur in Kerala. This paper provides detailed descriptions of 5 of the species collected from Kerala during the present survey. Among these, Drepanolejeunea erecta (Steph.) Mizut. is new to the Western Ghats, D. fleischeri (Steph.) Grolle & Zhu, D. pentadactyla (Mont.) Steph. and D. ternatensis (Gottsche) Steph. are new records for Kerala

Does the Number of Hours Spent on Learning Affect Academic Achievement?

Examinations are measurement tools designed to assess learners’ achievement of course learning outcomes. Past studies have shown that factors such as motivation and study time play a part in enhancing learner achievement in assessment. The objective of this exploratory study is to develop a Regression Model that will be used to identify the possible relationship between the learners’ study time with their academic achievement. An online questionnaire survey was administered to 98 respondents of year 1 distance learners of the Principle of Management course in the January 2021 semester at Open University Malaysia. The data on the self-report of study time by the learners for the two variables were analysed. A regression analysis via Statistical Package for Social Sciences (SPSS) analysis tool was performed to study the relationship between the study time (for completing the assignment and preparing for the final examination) and academic achievement. The findings of this study suggest that a regression model can significantly predict academic achievement. However, based on this model, only the study time allocated for completing the assignment appears to be significantly correlated to the course assessment achievement. It is hoped that the findings gathered will lay the foundation for future research that take into consideration other relevant factors associated with study time and academic achievement

Molecular Basis for the Substrate Specificity of Quorum Signal Synthases

In several Proteobacteria, LuxI-type enzymes catalyze the biosynthesis of acyl–homoserine lactones (AHL) signals using S-adenosyl– L-methionine and either cellular acyl carrier protein (ACP)-coupled fatty acids or CoA–aryl/acyl moieties as progenitors. Little is known about the molecular mechanism of signal biosynthesis, the basis for substrate specificity, or the rationale for donor specificity for any LuxI member. Here, we present several cocrystal structures of BjaI, a CoAdependent LuxI homolog that represent views of enzyme complexes that exist along the reaction coordinate of signal synthesis. Complementary biophysical, structure–function, and kinetic analysis define the features that facilitate the unusual acyl conjugation with S-adenosylmethionine (SAM). We also identify the determinant that establishes specificity for the acyl donor and identify residues that are critical for acyl/aryl specificity. These results highlight howa prevalent scaffold has evolved to catalyze quorum signal synthesis and provide a framework for the design of small-molecule antagonists of quorum signaling

Assimilating socio-economic perspective in designing crop sector technology interventions: A farmer participatory study on coconut sector in Kerala

The economic viability of coconut farming in the state has witnessed a steady decline due to a complex interplay of several socio-economic, environmental and institutional factors. But the crop sustains the livelihood of a significant share of the population in the state. Equitable growth in agricultural sector of the state cannot be attained unless the fortunes of coconut farming sector are revived. A critical understanding of the production environment is very important in crafting appropriate strategies for the sector. This study is based on a detailed analysis of socio-economic profile of 180 coconut farmers in Kerala across five major agro-ecological units, collected using pre-tested structured questionnaire. The study draws on trends in relevant socio-economic trends to examine the reasons for the vicious cycle of low investment-low profits -low productivity. The study identified structural agrarian changes like low dependence on farm income, High share of non-farm income, high cost and non-availability of skilled labour, etc., as contributing factors to the extant situation. Based on the socio-economic profile of the coconut farmer and technical studies, soil nutrient management centric strategy was identified as the key element in reorienting coconut farming. The intervention strategy was designed as an alternative approach for reviving the economic viability of coconut farming. The initial results on farmer perception on impact of technology intervention, with direct and indirect links to several biological and socio-economic limiting factors, indicate significant improvement across several parameters influencing crop productivity. Assimilating the lessons from the operation of the intervention strategy, the study also outlines a roadmap for multiple institutional involvements for scaling up this strategy across the state

Subsurface signatures and timing of extreme wave events along the Southeast Indian coast

Written history's limitation becomes apparent when attempting to document the predecessors of extreme coastal events in the Indian Ocean, from 550-700 years in Thailand and 1000 years in Indonesia. Detailed ground-penetrating radar (GPR) surveys in Mahabalipuram, southeast India, complemented with sedimentological analyses, magnetic susceptibility measurements, and optical dating provide strong evidence of extreme wave events during the past 3700 years. The diagnostic event signatures include the extent and elevation of the deposits, as well as morphologic similarity of buried erosional scarps to those reported in northern Sumatra region. Optical ages immediately overlying the imaged discontinuities that coincides with high concentration of heavy minerals date the erosional events to 340 ± 35, 350 ± 20, 490 ± 30, 880 ± 40, 1080 ± 60, 1175 ± 188, 2193 ± 266, 2235 ± 881, 2489 ± 293, 2450 ± 130, 2585 ± 609, 3710 ± 200 years ago. These evidences are crucial in reconstructing paleo extreme wave events and will pave the way for regional correlation of erosional horizons along the northern margin of Indian Ocean

An evaluation of crude palm oil (CPO) and tocotrienol rich fraction (TRF) of palm oil as percutaneous permeation enhancers using full-thickness human skin

The drawbacks associated with chemical skin permeation enhancers such as skin irritation and toxicity necessitated the research to focus on potential permeation enhancers with a perceived lower toxicity. Crude palm oil (CPO) is obtained by direct compression of the mesocarp of the fruit of the oil palm belonging to the genus Elaeis. In this research, CPO and tocotrienol-rich fraction (TRF) of palm oil were evaluated for the first time as skin permeation enhancers using full-thickness human skin. The in vitro permeation experiments were conducted using excised human skin mounted in static upright ‘Franz-type’ diffusion cells. The drugs selected to evaluate the enhancing effects of these palm oil derivatives were 5-fluorouracil, lidocaine and ibuprofen: compounds covering a wide range of Log p values. It was demonstrated that CPO and TRF were capable of enhancing the percutaneous permeation of drugs across full-thickness human skin in vitro. Both TRF and CPO were shown to significantly enhance the permeation of ibuprofen with flux values of 30.6 µg/cm2 h and 23.0 µg/cm2 h respectively, compared to the control with a flux of 16.2 µg/cm2 h. The outcome of this research opens further scope for investigation on the transdermal penetration enhancement activity of pure compounds derived from palm oil

Multiband tight-binding theory of disordered ABC semiconductor quantum dots: Application to the optical properties of alloyed CdZnSe nanocrystals

Zero-dimensional nanocrystals, as obtained by chemical synthesis, offer a broad range of applications, as their spectrum and thus their excitation gap can be tailored by variation of their size. Additionally, nanocrystals of the type ABC can be realized by alloying of two pure compound semiconductor materials AC and BC, which allows for a continuous tuning of their absorption and emission spectrum with the concentration x. We use the single-particle energies and wave functions calculated from a multiband sp^3 empirical tight-binding model in combination with the configuration interaction scheme to calculate the optical properties of CdZnSe nanocrystals with a spherical shape. In contrast to common mean-field approaches like the virtual crystal approximation (VCA), we treat the disorder on a microscopic level by taking into account a finite number of realizations for each size and concentration. We then compare the results for the optical properties with recent experimental data and calculate the optical bowing coefficient for further sizes

Structural genomics is the largest contributor of novel structural leverage

The Protein Structural Initiative (PSI) at the US National Institutes of Health (NIH) is funding four large-scale centers for structural genomics (SG). These centers systematically target many large families without structural coverage, as well as very large families with inadequate structural coverage. Here, we report a few simple metrics that demonstrate how successfully these efforts optimize structural coverage: while the PSI-2 (2005-now) contributed more than 8% of all structures deposited into the PDB, it contributed over 20% of all novel structures (i.e. structures for protein sequences with no structural representative in the PDB on the date of deposition). The structural coverage of the protein universe represented by today’s UniProt (v12.8) has increased linearly from 1992 to 2008; structural genomics has contributed significantly to the maintenance of this growth rate. Success in increasing novel leverage (defined in Liu et al. in Nat Biotechnol 25:849–851, 2007) has resulted from systematic targeting of large families. PSI’s per structure contribution to novel leverage was over 4-fold higher than that for non-PSI structural biology efforts during the past 8 years. If the success of the PSI continues, it may just take another ~15 years to cover most sequences in the current UniProt database