Learning to teach online: student teachers’ perceptions of an online English language teaching practicum at a Sri Lankan state university

This study examines student-teacher perceptions  of an English language teaching practicum conducted online in 2020 and 2021 at a state university in Sri Lanka. This non-experimental case study investigates the changes in perceptions  of participants towards online learning, teaching, online interactions, and perceptions towards the online platform as a learning environment. Using a 5 point Likert Scale format (in the pre survey) and 4 point Likert Scale format (in the post survey), this study explored 64 student-teachers’ perceptions  towards a newly converted online practicum. The student-teachers took part in a pre and post  questionnaire at the beginning and end of the practicum. Detailed information about their online experiences was gathered through an open ended question given to all students. Questions focused on perceptions  about teaching, learning online, administration of course, development of needs analyses, lesson material, duration and completion of course. The results show that participants’ perceptions  at the beginning of the course improved significantly towards the latter part of the course when reaching completion in 2020 when the online practicum was newly introduced. Significantly, students who were following online lectures in the year 2021 have reacted positively to the online practicum. Detailed comments provide more insights into the learning, teaching strategies encountered in the online teaching practicum. The study indicates the factors that can make a difference to change the perceptions  of student-teachers in curriculum, assessment, teaching and learning strategies. It also offers an alternative mechanism to conduct teaching practicums during challenging times. KEYWORDS: Online teaching, Teaching educator, Teaching practicum, English as a Second Language, Pandemi

GROWTH AND BIOMASS ACCUMULATION OF SOME EARLY SUCCESSIONAL WOODY SPECIES IN AN UPROOTED RUBBER FIELD AT KAMBURUPITIYA

A study was conducted on a successional vegetation in an abandoned uprooted rubber fieldat Kamburupitiya in 1999. It involved determination of growth parameters such as height.girth. biomass accumulation and partitioning of dry matter in three most widely occurringearly successional woody species, namely Macarange peltata, Alstonia scliolaris and Tremaoricnralis of varying ages (3. 5 and 7 years). Here three trees of each species were sampledexcept A. scholaris where only 3 and 5 year old trees were sampled for each age class fromeach succeessional stand.Growth parameters (height, gbh and rate of height and diameter), growth of all three speciesat 3. 5 and 7 years and the partitioning of dry matter to the leaves were compared among thethree tree species and the ages sampled. According to the results obtained A. scholarisshowed the highest absolute and relative stem elongation followed by M. peltata and then Torienta/is. However it recorded the lowest rate of increment in girth. At three years of agemore dry matter is heing partitioned to leaves and as the age progressed this proportion ISsignificantly reduced in all the tree species sampled.The implications of inter-specific variations in growth attrihutes and accumulation andpartition of dry matter on nutrient conservation and restoration of disturhed agro-ecosystemsare discussed.

SUCCESSIONAL DEVELOPMENTS IN SOME HUMAN-IMPACTED AREAS AT KAMBURUPITIYA FOLLOWING THE NILWALA PROJECT

A study on successional development at a human-Impacted sitl' W;I~ conducted atKurnburupiuya from June to October 1'1\)9. This site was previously maintained underauroforcxtrv. but has been scvcrclv disturbed and its soil has been removed do wn t(l theb~drock in "19~7, under the N i1wala" project. Three such sites ( 12 X H)I, 2 X I ()4, I X 10· me)which are about 500 meters apart were selected for the study, The study involvedcharacterisation of the physical and chemical properties of the soil and assessment ofsuccessional development. An undisturbed site was used as the control experiment.Bulk density, true density and porosity of the soil were 1,163 gem". 2.14 gcrn', and 45.6gcm'. respectively, with a water holding capacity of 2H.5'11:,The per cent of organic matterand N in the soil were 0.451 and 0,0088. respectively, whereas the corresponding values forthe undisturbed site. were 1,214 and 0.095, The cation exchange capacity of the derelictsites was 4,71 m.e. per IOOg of soil and had a pH value of 4.2. The corresponding figuresfor the reference site were 7.40 and 5.43, respectively, Plant populations in three sites were15.LJ02. 21.266 and LJ~.776 ha I, Even after 12 years. only about 0,13-0.26(1, of plants had agIrth exceeding 3 em at breast height and only about I (I, of plants had a height greater than1111. Twenty one species occurred in three sites. which belonged to sixteen families. namely(in order of ahundance). Grarninac. Gleichcriaccac, Apocynaceac, Lcgurninoxac.Vcrhanaccac. Rubiaccac, Burseraccue. Cyperaccac, Compositac, Malvaccac. l.auraccac.Pcriplocuccac. Mclastomaiaccac. Luphohiuceae, Anacardiaccae and Rhizophoraccac. orthese species, about 75% were herbaceous whilc the rest were woody. Alstonia scholaris\\as by fur the most abundant and dominant woody species followed by Cinnamon VC/'IIII/.Carallia brachita, Even alter 12 years of thc disturbance, the hiomass production ofAlstonia scholaris was only 9.5 gm·2 or 95 kha'. showing an extremely successionaldevelopment. Ecological implications of such a tardy successional development and humaninterventions required to facilitate and catalyse the natural successional processes arediscussed,

Quantifying and Controlling Prethermal Nonergodicity in Interacting Floquet Matter

The use of periodic driving for synthesizing many-body quantum states depends crucially on the existence of a prethermal regime, which exhibits drive-tunable properties while forestalling the effects of heating. This dependence motivates the search for direct experimental probes of the underlying localized nonergodic nature of the wave function in this metastable regime. We report experiments on a many-body Floquet system consisting of atoms in an optical lattice subjected to ultrastrong sign-changing amplitude modulation. Using a double-quench protocol, we measure an inverse participation ratio quantifying the degree of prethermal localization as a function of tunable drive parameters and interactions. We obtain a complete prethermal map of the drive-dependent properties of Floquet matter spanning four square decades of parameter space. Following the full time evolution, we observe sequential formation of two prethermal plateaux, interaction-driven ergodicity, and strongly frequency-dependent dynamics of long-time thermalization. The quantitative characterization of the prethermal Floquet matter realized in these experiments, along with the demonstration of control of its properties by variation of drive parameters and interactions, opens a new frontier for probing far-from-equilibrium quantum statistical mechanics and new possibilities for dynamical quantum engineering

NUTRITIONAL RETRANSLOCATION EFFICIENCIES IN SOME AGROFORESTRY SPECIES OF SRI LANKA

Studies on nutrient resorption efficiency or 13 major agroforcstry spccles (Gltricli/wIcpiu Ill. Alstonia SCIIOI(/ris. MU((/r({/lgu peltuta, Artocarpus intcgrijoli«, ArI(}(,{lJpIIS altili»,Milngllel'{{ indica, Tcrniinalia c({{I(//NI, Acacia auricu litorm is, Acacia tnanguu«. l'sidimnglliljil\,({, Ncpheliutn /(IPP({CCIIIll, M(//lilk({lYI sapota and Trctua orientalis; ill Sri Lanka wereconducted at the Faculty or Agriculture, Mapalana. Kamburupiuyu during 1<)<)7NX. Here.three trees from each species, and 3 branches from each tree were randomly selected andmature and senescent leaves were collected from each branch and analyscd tor per centnitroucn, phosphorous and potassium,Considerable variations in foliar nutrient concentration were evident among the species aswell as within species, depending on the ontogenic stage of leaves, Both in mature andsenescent leaves G, scpiuni showed the highest concentration or nitrogen (3,5 I(I( and 2.4(1r.respectively) while M, indica had the lowest (1.42(1r and 0.41 (Ir. rcspcctivc ly). Significantinter-specific variation in nitrogen translocation efficiency (NRE) was observed (1'::= 0,(1).which varied 28.94 to 54,9YX, T ('(I1I({pa had the highest value while G, scpiutn had thelowest. M, indica (48,78'1r) T oricntalis (48,6Y'/c1 also had a relatively high NRE, NREs ofN. lappcceum. M, sapota, A, integritolia, A, altilis, A, auriculifonnis. M, peltata. A.nuingiun). A, scltolaris and P. ,lilliljm'o were 43,39, 42,57. 42.43. 41 ,X3, 40.41. 39,76. 36,XO._)4,53 and 31.XX%. respectively, P. gllojava had the highest concentration of phosphorousboth in mature (O,33X'X) and senescent (0,204'1r) leaves, As for potassium. M, sapota hadthe highest concentration both in mature (I ,07X'1r) and senescent (0,73'1r J leaves. Torientalis showed the highest phosphorous resorption efficiency (PRE). I.C, 62,7(Ir, whichwas significantly higher than that of N. lappaceutn (50,27(1r J, M, sapota (40,OY(Ir) and P.,lil/aja\'{{ (37,W1r.), M. sapota had the highest potassium resorption efficiency (32,99(1r)followed by T oricntalis (2Y,64(Ir), N. lappaccuni (26,97(1r) and P. glliljU\'(/ (2:~,55(;'), Butthey did not differ significantly, Possible implications of nutrient rctranslocation onadaptability of trees to nutrient limiting situations and succcssionnl development Indisturbed terrestrial ecosystems are discussed,

Direct Bandgap Cross-over Point of Ge\u3csub\u3e1-y\u3c/sub\u3eSn\u3csub\u3ey\u3c/sub\u3e Grown on Si Estimated through Temperature-dependent Photoluminescence Studies

Epitaxial Ge1-ySny (y = 0%–7.5%) alloys grown on either Si or Ge-buffered Si substrates by chemical vapor deposition were studied as a function of Sn content using temperature-dependent photoluminescence (PL). PL emission peaks from both the direct bandgap (Γ-valley) and the indirect bandgap (L-valley) to the valence band (denoted by ED and EID, respectively) were clearly observed at 125 and 175 K for most Ge1-ySny samples studied. At 300 K, however, all of the samples exhibited dominant ED emission with either very weak or no measureable EID emission. At 10 K, ED is dominant only for Ge1-ySny with y \u3e 0.052. From the PL spectra taken at 125 and 175 K, the unstrained indirect and direct bandgap energies were calculated and are plotted as a function of Sn concentration, the results of which show that the indirect-to-direct bandgap transition occurs at ∼6.7% Sn. It is believed that the true indirect-to-direct bandgap cross-over of unstrained Ge1-ySny might also take place at about the same Sn content at room temperature. This observation suggests that these Ge1-ySny alloys could become very promising direct bandgap semiconductor materials, which will be very useful for the development of various new novel Si- and Ge-based infrared optoelectronic devices that can be fully integrated with current technology on a single Si chip

Enriching BIM with unmanned aerial systems data for enhancing construction management operations

The use of an unmanned aerial system (UAS) in construction project management (CPM) is an emerging methodology aimed at improving the performance of project management practices. Despite the different functions that an UAS offers, which are well covered in various sources ranging from isolated exploratory works to ad hoc case studies, construction practitioners still demonstrate little interest in UAS technology. The underwhelming interest is rooted in a lack of an understanding of the value of the data collected using UASs and their potential to enrich Building Information Modelling (BIM). This research presents the details of the UAS developed to check the accuracy of work performed, along with the generation of the corresponding progress payment reports as well as referencing and tracking information in real time, for a residential project. This study also discusses combining the data generated from the UAS and 5D BIM to develop a smart construction site. The UAS–BIM combination enables the project stakeholders to be fully informed of the work’s progress and quality to avoid mistakes that could lead to extra costs and delays. The paper identified the main obstacles to applying the UAS via interviews with the project managers and tradespersons involved in the selected project. Assuredly, a digital culture is essential for a smart construction site to shift the project team from a passive data user to a more proactive analyzer to improve performance and site safety. Other obstacles include ethical reservations, legal requirements, liability risks, weather conditions, and the continuation of using an UAS in non-open-air construction environments

EFFECT OF AGRICULTURE ON ENVIRONMENT

The burgeoning population in this country is making increasing demands on agriculture.Consequently, there is mounting pressure on the natural resource base, particularly on landfor increased food production. Failure to adopt appropriate soil and water conservationpractices in agriculture has resulted in considerable soil erosion and land degradation,rendering a large extent of agricultural lands marginal and unproductive. Due todemographic pressure, agriculture is being extended even to sloping lands, causing heavysoil erosion. Moreover, shifting cultivation has continued unabated, further dwindling theforest cover, which has already reached a threshold value. With the advent of improvedvarieties, large quantities of agrochemicals such as inorganic fertilizers, insecticides,herbicides, fungicides etc. are being released to the environment. Many of farmers usepesticides indiscriminately polluting the soil, water and the food they produce, causingserious environmental and health problems.Some major consequences of improper agricultural practices are the loss of soil fertility,land degradation, siltation of rivers and reservoirs, occurrence of flash floods,eutrophication of water bodies with attendant reduction in hydro-power generation, loss ofbiodiversity, emissions of green house gases such as CO2 and NO", which have far-reachingenvironmental, social, economic and political implications. The major causes ofagriculture-related environmental problems, their effects and consequences and measuresto mitigate them are discussed

CHEMISTRY OF LEAF LINER OF SOME AGRO-FORESTRY SPECIES IN SRI LANKA

Dl'l'llillpmilion or k:l! litter ix a major process in the nutrient dyn.nnicx of agroccosystcm»,which is intricnlly gOVL'lllcd hv the liner chemistry, The chemistry of leaf litter dctcrrnincshOlh the umc course of decomposition and the nutrient rcIC:1SCpaucrn. There arc many:I,~rIllorc'strv Spl'l'leS in Sri 1.:1111-::1h.ili information nvailahk- Oil their liner chcmixirv ISxc.uuv. Such information provcx useful ill idelltifying :1J'[1ropri:ltl' agrofon'stry spccie,s Iordnl'lopillg xuxtainahlr agrol'U)systl'IllS, Therefore studies were carried out to dcrcrm incIhe l'lllll'l'lltr:I1iolls Ill' nutricius II.; N. P. K, Ca and Mg ), ligllill .md ccllulnxr or nine:1~J()fmeslry spl'l'ies ill Sri Lanka. vii .. Acacia auriculijonnis, Acacia mangium. Giriridia,\('I'lllll!, Maccnan;« !1ciIUIU (Kallde J. Altoni« srholaris (Alstonia). Artocurnus il/lcgrU(J/iarluk J, Aruuntpu» altilis (bread truin. 11'/lIIiI/0//(/ ('(11111/10 (Indian almond), and MOI/.~It('r'lindica (m:1I1goI.Considerable interspecific variation in the above parameters was observed in the leaf litter.Ax rl'g:lI'<ls the per ccntx of ",y, K. C:I and Mg. the values observed varied from 0,39'1 -1(12, OJ)2'i - 0,171. () 16 - 0,9'1. 1.76 - 2,'17 and (I.n - 0.'1 I. respectively. The highestconcentration of N W:IS in (; scpittm while A altilis, A. altilis. A. il/lcgrifiJ/iil and A.sclioars had the highest conccutrarion of P. K. Ca and Mg. respectively. This underlinesIhl' importance of introducinu diverse species (hiological diversity) ill order to cxrablish abalanced Icrtility regime. Milldim and A. ntangiurn had the highest concentration oflignin (22.9l) %) and cellulose 132.76 %). respectively. A salient feature in the leaf litter inM. indica W:IS that. it had the lowest concentration of N (0.39'1 %) and cellulose (14.59 %)and the highest concentration of lignin (n.99%). These data prove useful in identifying asuitable combination of agroforcsuy species for sustainable soil fertility management.

Fatty Acid Composition of Beef from Cattle Fed Wet Distillers Grains Diets Supplemented with Vitamin E

Crossbred yearlings (n = 90) were allotted to one of ten diets containing 0%, 20% and 40% wet distillers grains (WDG) with or without vitamin E supplementation and distillers solubles. Strip loin and tenderloin steaks were obtained and tested for their fatty acid profiles using gas chromatography. WDG diets increased linearly (P \u3c 0.05) the polyunsaturated fatty acids (PUFA) containing 18 or more carbons and trans fatty acids in both muscles. No significant differences were found for total saturated and unsaturated fatty acids. Dietary inclusion of neither vitamin E nor distiller solubles significantly changed PUFA, trans, omega-6 or omega-3 fats in strip loins and tenderloins. Therefore, changes in the fat¬ty acid profile of beef are a consequence of WDG, not the solubles or vitamin E