Seed Rain in a Tropical Lowland Rainforest Fragment in Central Sri Lanka

Fragmentation of tropical rainforests can adversely affect seed dynamics due to the habitat loss, changed habitat configuration and altered species interactions. Halgolla Forest Reserve (HFR) is an isolated tropical lowland wet evergreen rainforest fragment, located in central province of Sri Lanka. Despite its small size, it harbors high biodiversity with many endemic species. However the biodiversity of HFR is highly threatened due to the agricultural expansion, illegal encroachments and logging. Thus, the study investigated the regeneration potential of the fragment by assessing seed rain dynamics in HFR. Comparisons were made for seed density and species diversity in seed rain of the forest edge (highly disturbed), riverine area (less disturbed) and forest interior (undisturbed) habitats for one year. Thirty plots of 10×10 m2 (ten plots each per habitat) were established using stratified random sampling at the forest edge, forest interior and riverine areas. Seed traps (1×1 m2) were placed in each plot and contents of traps were collected once in two weeks from November 2017 to November 2018. Seed morphotypes and abundance of species were recorded and diversity indices were calculated to make the comparisons between the three habitats. A total number of 28,714 seeds were recorded under 107 morphospecies in the seed rain. The seed density was higher in the forest edge (1,659.6 m-2year-1) than in the forest interior (533.1 m-2year-1) and the riverine habitat (678.8 m-2year-1). The differences in seed density between forest edge and interior habitats may be due to the altered seed dispersal patterns after fragmentation. Seed rain peaked at the end of dry season prior to the beginning of rainy season. The highest seed abundance was recorded by Ficus spp. in all three habitats. Species richness was more or less similar in all three habitats. Species diversity and evenness were lower in more disturbed forest edge than in forest interior and riverine habitats. HFR has a high regeneration potential probably due to being closer to other forest patches that can act as seed sources for HFR. However the influx of non-rainforest species through seed rain such as Coffea arabica L., Camellia sinensis (L.) Kuntze, Alstonia macrophylla Wall. ex G. Don and Swietenia macrophylla King from surrounding matrix is an evidence for habitat disturbance which indicate a threat to the regeneration of native species surviving in the forest fragment. Conservation of this forest fragment through enhanced awareness and community participation is vital to preserve this biodiversity refugium.Keywords: Seed rain, Tropical lowland rainforest fragment, Seed density, Species diversit

Similarity solutions of Fokker-Planck equation with time-dependent coefficients

In this work, we consider the solvability of the Fokker-Planck equation with both time-dependent drift and diffusion coefficients by means of the similarity method. By the introduction of the similarity variable, the Fokker-Planck equation is reduced to an ordinary differential equation. Adopting the natural requirement that the probability current density vanishes at the boundary, the resulted ordinary differential equation turns out to be integrable, and the probability density function can be given in closed form. New examples of exactly solvable Fokker-Planck equations are presented, and their properties analyzed.Comment: 13 pages, 8 figures. Version to appear in Ann. Phys. Presentation improved. Discussions and figures of easy examples remove

Emerging digital banking service quality dimensions and their impact on elderly customer satisfaction and engagement: a study in Sri Lankan context

This research is based on the impact of emerging digital banking service quality dimensions on elderly customer satisfaction and engagement in Sri Lankan context. Security and privacy, perceived usefulness, perceived ease of use, perceived personalization and web aesthetics have been identified as the emerging service qualities in this new age of digital banking. Research on emerging service quality dimensions has become very crucial to both academics and practitioners; however, very little scholarly research has directed service marketers as to how they can influence on elderly customer satisfaction and engagement. In recognition of these current gaps of knowledge, this thesis investigates three research gaps that are addressed through three research questions. First, the research explores how security and privacy, perceived usefulness, perceived ease of use, perceived personalization and web aesthetics influence the elderly customer satisfaction (RQ1). Second, the research investigates the influence of perceived personalization on elderly customer engagement (RQ2). Third, it investigates the impact of in-person engagement and digital engagement on elderly customer satisfaction (RQ3). To address the three research questions, research in this thesis employed a theory building study, followed by a theory-testing study, using a mixed-method approach. Study one used convergent interview method to collect data from 30 elderly customers who are engaged with a digital banking service provider for more than 6 months. The study qualitatively explored the interviewees’ perceptions of the security and privacy, perceived usefulness, perceived ease of use, perceived personalization, web aesthetics, in-person engagement and digital engagement. Study two collected data from digital banking customers (above the age of 60) of two leading retail banks in Sri Lanka, resulting in a sample of n=275. The data was collected using a web-based survey that contained 28 items. The factors contained in the conceptual model were drawn from both the literature and the theory-building study. The measurement items were drawn from prior research and thematic findings. Five-point Likert scale was used to measure the items. Structural equation modelling (SEM) was then used to analyse the hypothesized relationships in the model. Four out of nine hypothesized relationships were supported by the results of this theory-testing studyThe results of the study confirm that, all the five service quality dimensions identified (security and privacy, perceived usefulness, perceived ease of use, web aesthetics and perceived personalisation) are distinct constructs. The results also indicate that all five service quality dimensions have appropriate reliability and each dimension has a significant correlation with other dimensions and make a significant influence on digital banking habits of elderly customers on digital platform. Findings suggest that the perceived usefulness is the key driver of elderly customer satisfaction on digital banking, followed by in-person engagement, perceived personalization, security and privacy, perceived ease of use and web aesthetics respectively. It means that elderly customers are more satisfied and engaged if the digital banking service provider augment the value proposition of digital banking with a clear understanding of the special needs they have. In other words, elderly customers are willing to engage and learn more on digital banking and have a much better and fully fledged customer experience on digital platform. Key words: Service quality dimensions, digital banking, perceived - personalization, engagement and usefulness, customer satisfaction, in-person and digital engagement

Predicting the optimal rotation length of Teak plantations using a simulation model

The traditional problem in Forest Economics has been mainly dealt with the estimation of optimalrotation length for sustainable management. However, given the limitation of the availability of timeseries data on growth and management in forest plantations in Sri Lanka, such estimations are notfeasible. Against this background, this study attempted to develop a simulation model and predictrotational interval of teak plantation under different management conditions.A field survey was conducted to identify the plantation related parameters in the Kurunegala District.Meantime, a simulation model was developed with Microsoft Visual Basic and Microsoft Excel usingthe equations specified in the Teak Management Plan (1997) to supplement the field data. The pastdata obtained from the Forest Department was used to parameterize the model. Using the age andthe height of a plantation at a particular time, the model was capable of predicting the plantationrelated parameters such as dbh and timber volume over the time.According to the values predicted by the simulation model, four different categories were identifiedbased on the site index, which represents the level of growth of a stand. Rotational interval wasestimated using the Faustman rotational model at different discount rates. Thereby it was estimatedthat the rotational intervals for the four categories at discount rates 10%, 15% and 20% as 19, 17 and15 years respectively. The internal rate of return obtained through the simulation was above themarket rate of 12%. Though the model yielded shorter rotational intervals than the present fieldvalues, the approach could be used in future with more reliable field data.

Physiological responses to basic tastes for sensory evaluation of chocolate using biometric techniques

Facial expressions are in reaction to basic tastes by the response to receptor stimulation. The objective of this study was to assess the autonomic nervous system responses to basic tastes in chocolates and to identify relationships between conscious and unconscious responses from participants. Panelists (n = 45) tasted five chocolates with either salt, citric acid, sugar, or monosodium glutamate, which generated four distinctive basic tastes plus bitter, using dark chocolate. An integrated camera system, coupled with the Bio-Sensory application, was used to capture infrared thermal images, videos, and sensory responses. Outputs were used to assess skin temperature (ST), facial expressions, and heart rate (HR) as physiological responses. Sensory responses and emotions elicited during the chocolate tasting were evaluated using the application. Results showed that the most liked was sweet chocolate (9.01), while the least liked was salty chocolate (3.61). There were significant differences for overall liking (p < 0.05) but none for HR (p = 0.75) and ST (p = 0.27). Sweet chocolate was inversely associated with angry, and salty chocolate positively associated with sad. Positive emotion-terms were associated with sweet samples and liking in self-reported responses. Findings of this study may be used to assess novel tastes of chocolate in the industry based on conscious and emotional responses more objectively

Variable Step Random Walks and Self-Similar Distributions

We study a scenario under which variable step random walks give anomalous statistics. We begin by analyzing the Martingale Central Limit Theorem to find a sufficient condition for the limit distribution to be non-Gaussian. We note that the theorem implies that the scaling index $\zeta$ is 1/2. For corresponding continuous time processes, it is shown that the probability density function $W(x;t)$ satisfies the Fokker-Planck equation. Possible forms for the diffusion coefficient are given, and related to $W(x,t)$. Finally, we show how a time-series can be used to distinguish between these variable diffusion processes and L\'evy dynamics.Comment: 13pages, 2 figure

Convergent activation of two-pore channels mediated by the NAADP-binding proteins JPT2 and LSM12

The second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) evokes calcium ion (Ca2+) release from endosomes and lysosomes by activating two-pore channels (TPCs) on these organelles. Rather than directly binding to TPCs, NAADP associates with proteins that indirectly confer NAADP sensitivity to the TPC complex. We investigated whether and how the NAADP-binding proteins Jupiter microtubule-associated homolog 2 (JPT2) and like-Sm protein 12 (LSM12) contributed to NAADP-TPC-Ca2+ signaling in human cells. Biochemical and functional analyses revealed that recombinant JPT2 and LSM12 both bound to NAADP with high affinity and that endogenous JPT2 and LSM12 independently associated with TPC1 and TPC2. On the basis of knockout and rescue analyses, both NAADP-binding proteins were required to support NAADP-evoked Ca2+ signaling and contributed to endolysosomal trafficking of pseudotyped coronavirus particles. These data reveal that the NAADP-binding proteins JPT2 and LSM12 convergently regulate NAADP-evoked Ca2+ release and function through TPCs

Water balance and renewal time of rekawa lagoon, Sri Lanka; a restorative approach

Rekawa Lagoon is a chocked and shallow coastal water body located in the southern coast of Sri Lanka. It is relatively unusual in that the major freshwater input, Kirama-oya river connects through the constricted channel much closer to the inlet at seaward end. A causeway was constructed, around 700 m from the lagoon inlet to the inland, across the constricted channel with an effort to link a secluded Kapuhenwala village with the rest of the area which in turn greatly reduced the volume and speed of water entering and leaving the lagoon system. Construction of the causeway led to many environmental problems with poor flushing efficiency and hampering to and fro movement of the prawns in the lagoon. The aim of this study was to evaluate the present situation and propose alternative management scenarios for improvement of water flow and lagoon ecosystem. The implications of different development stages of the causeway were discussed in terms of field measurements supported by modeling to describe the water balance and the water renewal time. The alternative of modifying the existing causeway was proposed to increase the free water flow at the inlet that favors recruitment of juvenile shrimp species

Progesterone receptor membrane component 1 facilitates Ca²⁺ signal amplification between endosomes and the endoplasmic reticulum

Membrane contact sites (MCSs) between endosomes and the endoplasmic reticulum (ER) are thought to act as specialized trigger zones for Ca2+ signaling, where local Ca2+ released via endolysosomal ion channels is amplified by ER Ca2+-sensitive Ca2+ channels into global Ca2+ signals. Such amplification is integral to the action of the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). However, functional regulators of inter-organellar Ca2+ crosstalk between endosomes and the ER remain poorly defined. Here, we identify progesterone receptor membrane component 1 (PGRMC1), an ER transmembrane protein that undergoes a unique heme-dependent dimerization, as an interactor of the endosomal two pore channel, TPC1. NAADP-dependent Ca2+ signals were potentiated by PGRMC1 overexpression through enhanced functional coupling between endosomal and ER Ca2+ stores and inhibited upon PGRMC1 knockdown. Point mutants in PGMRC1 or pharmacological manipulations that reduced its interaction with TPC1 were without effect. PGRMC1 therefore serves as a TPC1 interactor that regulates ER-endosomal coupling with functional implications for cellular Ca2+ dynamics and potentially the distribution of heme