Eastern Bhutan Research Articles

Geomorphological evidence inconvenient for the antecedent rivers of the Arun and Tista across the Himalayan range

The Arun and Tista Rivers, which flow across the Himalayas, are commonly known as antecedent valleys that overcame the rapid uplift of the Higher Himalayan ranges. To clarify whether the idea of antecedent rivers is acceptable, we investigated the geomorphology of the Himalayas between eastern Nepal and Bhutan Himalayas. The southern part of Tibetan Plateau, extending across the Himalayas as tectonically un-deformed glaciated terrain named as ‘Tibetan Corridor,’ does not suggest the regional uplift of the Higher Himalayas. The 8,000-m class mountains of Everest, Makalu, and Kanchenjunga are isolated residual peaks on the glaciated terrain composed of mountain peaks of 4,000–6,000 m high. The Tibetan glaciers commonly beheaded by Himalayan glaciers along the great watershed of the Himalayas suggest the expansion of Himalayan river drainage by glaciation. For the narrow upstream regions of the Arun and Tista Rivers with less precipitation behind the range, it is hard to collect enough water for the power of down-cutting their channels against the uplifting Himalayas. The fission track ages of the Higher Himalayan Crystalline Nappe suggest that the Himalayas attained their present altitude by 11–10 Ma, and the Arun and Tista Rivers formed deep gorges across the Himalayas by headward erosion.

The Relationship Between PM2.5 Concentration and Meteorological Parameters at Sherubtse College, Eastern Bhutan

This study was conducted at Sherubtse College located at Kanglung gewog under Trashigang dzongkhag to validate the relationship between PM2.5 concentration and meteorological parameters. R Studio version 2023.09.1+494 and Microsoft Excel 2019 were used to analyze and visually represent the data. Karl Pearson correlation was used to correlate concentration of PM2.5 to the metrological factors. The aims of this study were to evaluate the effects of metrological factors on the concentration of PM2.5 and to determine annual and seasonal variations associated with PM2.5 concentration. The study showed that 113 days in 2022 had crossed the WHO 24 hours limit of PM2.5 concentration. The study indicated that PM2.5 had strongest correlation with temperature (r = -0.41) followed by precipitation (r = -0.17). However, there was difference in the strength of correlation in various season. The study also concluded that the intensity of rain is inversely proportional to the concentration of PM2.5. Furthermore, the concentration of PM2.5 is dominated by the wind flowing from the southern area from the study location. Thus, this study suggests that the variation in concentration of PM2.5 should be considered during policy formulation and for better health of people living in Kanglung gewog and across the country.

Seroprevalence and risk factors associated with bovine tuberculosis in cattle in Eastern Bhutan.

Bovine tuberculosis (bTB) is a chronic zoonotic disease affecting cattle of all age groups including wild animals. It poses a significant threat to public health and high economic losses to dairy farmers. While the disease has been eradicated from most of the developed countries through extensive surveillance, testing and culling strategy, it is endemic in Africa, Asia, and the Middle East countries. Currently, there is limited research regarding the prevalence of bTB in cattle in Bhutan. This study aimed to determine the seroprevalence of bTB in cattle in six districts of eastern Bhutan. A two-stage probability proportional to size (PPS) sampling strategy was used to determine the number of animals from which serum samples needed to be collected in each district and sub-district. All farms and cattle for sampling were randomly selected from the data in the annual livestock census of 2020. The samples were tested using bTB ELISA test kit. The seroprevalence and their 95% confidence intervals were calculated. Logistic regression models were constructed to assess the influence of various individual animal and environmental risk factors (breed, age, sex, source of animal, body condition scores of animals, respiratory system status) associated with sero-positivity in animals. The study revealed an apparent seroprevalence of 2.57% (25/971 cattle; 95% CI:1.58-3.57), with an estimated true seroprevalence of 0.91% (95% CI: 0.0-2.81). However, none of the variables were found to be significantly associated with bTB seroprevalence in cattle. We recommend, further sampling and employment of confirmatory testing to fully ascertain the extent of bTB in the cattle herds in eastern Bhutan for prevention and control.

New Record of Plants from Eastern Bhutan

No Abstract.

Establishment of a high-yield intercropping system for maize and legumes under rainfed conditions in eastern Bhutan

ABSTRACT Maize-legume intercropping is a sustainable strategy to improve maize production for smallholder farmers. Maize is a staple food crop in Bhutan and integration of legumes with maize has been considered as an alternative option towards enhancing maize production in the country. Here, we conducted two studies in eastern Bhutan: first study (2021) to identify suitable legumes for intercropping with maize and second study (2022) to evaluate the effects of different maize-soybean intercropping patterns on grain yield, land use efficiency, and economic benefits. The maize-soybean intercropping system showed better productivity and economic viability than the kidney bean and groundnut systems in both the sites. Row intercropping and strip intercropping with 2 rows of maize alternating with 2 rows of soybean (2 M:2S) spaced 0.3 × 0.3 m showed stable and consistently higher grain yield at Lingmethang and Wengkhar (LING = 6.05 t ha−1; WENG = 8.37 t ha−1). The land equivalent ratio (LING = 1.78; WENG = 1.73) and net return (0.16 million Nu. ha−1 for LING and 0.21 million Nu. ha−1 for WENG) were notably higher for these intercropping methods. Our results suggest that the integration of legumes between conventional maize planting density, row intercropping and strip intercropping (2 M:2S) spaced at 0.3 × 0.3 m would be beneficial for achieving higher productivity for smallholder farmers in eastern Bhutan.

Climate and humans interact to shape the fire regime of a chir pine (Pinus roxburghii) forest in eastern Bhutan

BackgroundChir pine (Pinus roxburghii Sarg.) forests are distributed in the dry valleys of Bhutan Himalaya. In the past, these forests have been heavily influenced by human activities such as grazing, burning, resin tapping, and collection of non-timber forest products. Bhutan’s Forest Act of 1969, which shifted forest management from local community control to centralized governmental control, greatly restricted these activities. To understand the implications of the Forest Act on the chir pine forests, we used tree-rings and fire scars to reconstruct the fire history of a chir pine forest in eastern Bhutan. This provided an opportunity to characterize the fire regime before and after the Forest Act of 1969 was implemented and assess the scale and magnitude of changes that have occurred.ResultsWe developed a 120-year chir pine fire chronology from nine sites within a single forested landscape. Between 1900 and ~ 1970, fires were small and patchy. When fires occurred, they were limited to one to two sites within the larger study area. After 1970, there was a distinct shift in fire activity, with fires in 1985, 1989, 1996, 2000, and 2013 burning > 90% of sample plots. Fire activity was positively associated with La Niña conditions (wetter, cooler) in the preceding year. This is likely the result of increased accumulation and connectivity of fuels on the forest floor in wetter years. ConclusionsPrior to 1970, the fire regime in the studied chir pine landscape in eastern Bhutan was dominated by patchy, low-intensity fires indicating that the fire regime was fuel limited. After 1970, fires became larger and more frequent. This shift was associated with the enactment of the Bhutan Forest Act in 1969, which regulated grazing and implemented a policy of strict fire exclusion in government-reserved forests. This likely led to a large buildup of fuels, particularly after La Niña years. Historical patterns of grazing and low-intensity fires prior to the Forest Act kept fuel loads low and disconnected. The cessation of most human activities in these forests after 1969 resulted in an increase in fuel loads and connectivity within the landscape. This has greatly reshaped fire regimes in the chir pine forests of eastern Bhutan over the past half century.

Local or regional flaps in developing country: Experience from Eastern Bhutan.

Soft tissue reconstruction plays an integral part in orthopaedic surgery. For developing country like Bhutan, where no micro-surgical or plastic surgeons are available, orthopaedic surgeons perform the local or regional flaps for the soft tissue defects. In this paper, we describe the use of different kinds of local and regional flaps and its outcome at Eastern Regional Referral Hospital, Bhutan.

Analyzing Teachers' Attitude towards Integrating Technology in Teaching and Learning

An attempt has been made to investigate the technology acceptance in teaching in relation to attitude of school teachers'. The focus of the research is to-evaluate the school teachers' attitude towards technology acceptance in teaching; find the difference in female and male school teachers' attitude towards technology acceptance in teaching. Method used for data collection was descriptive survey. A sample of three hundred and four school teachers (comprising of 151 female and 153 male school teachers) was drawn from eighteen government school (six districts namely Samdrup Jongkhar, Pema Gatshel, Tashi Gang, Tashi Yangtse, Mongar and Lhuntse of Bhutan) of Eastern Bhutan through convenience sampling. The objective and hypotheses of the study have been tested by using mean, standard deviation, frequencies, percentages and z'-test. Results revealed that 1) majority of school teachers have positive (highly favorable and favorable) attitude towards the technology acceptance in teaching; and 2) Attitude of female and male school teachers towards technology acceptance in teaching do not differ significantly from each other. Female and male school teachers have favorable attitude, to equal extent or degree, towards the technology acceptance in teaching.

Landslide Susceptibility and Risk Mapping in the Tectonic Ensemble Comprising of Eastern Himalayan Zone, Northeast India and Bhutan using Logistic Regression and Random Forest Techniques

Abstract The mountainous terrain of the East-Northeast tectonic ensemble covers an approximate area of 3,11,420 km2 comprising the Eastern Himalayan zone, Northeast India and Bhutan is prone to mass movements. The increasing trend of landslide occurrences in the last few decades sets loud alarm bells for mapping the landslide hotspot zones in terms of Landslide Susceptibility and Risk. Initially, a landslide inventory of around 9751 landslides has been prepared, of which 6826 (70%) has been randomly picked as training dataset and the remaining 2925 (30%) as the testing dataset. Thereafter, Random Forest (RF) and binary Logistic Regression (LR) based Landslide Susceptibility Zonation (LSZ) have been prepared through twelve predictor layers viz. Slope Angle, Slope Aspect, Slope Curvature, Distance to Drainage, Distance to Lineament, Landform, Surface Geology, Distance to Road, Normalized Difference Vegetation Index (NDVI), Landuse/ Landcover (LULC), Rainfall and Epicentre Proximity. Both the Landslide Susceptibility Index (LSI) maps are divided into five classes, viz. ‘low’, ‘moderate’, ‘high’, ‘very high’ and ’severe’, which are then validated statistically by drawing a comparison with the 30% testing chronological landslide inventory database. The statistical index based accuracy assessment in terms of Area Under the Curve (AUC) exhibits an LR model AUC of 0.776 and RF model AUC of 0.820. However, it has been observed that the RF model strongly correlates with the testing inventory dataset exhibiting that around 46% of the landslide-prone terrain is classified in the ‘high to severe’ zones with 41% inventory landslides occurring in these zones. Integrating the Random Forest (RF) based LSI thematic layer with the socio-economic vulnerability layers like the Number of Households and Population Density have demarcated around 20.78% of the region under ‘very high to severe’ socio-economic risk as convoluted by landslide susceptibility in the terrain. The present findings are expected to be useful in urban development and town planning with appropriate slope management and land-use planning.

Assessment of Socio-economic Impact of Human-wildlife Conflict on Agriculture: A Case of Smallholder and Subsistence Farmers in Eastern Bhutan

Human-wildlife conflicts are a great concern in where ecosystem services are shared between humans and wildlife animals. This paper examines the socio-economic impacts of human-wildlife conflicts. A descriptive survey design was employed in this study. Primary data were collected by using a simple random sample from 120 households. Data were analyzed using descriptive statistics including frequency and percentages. The study results showed that there is a substantial social and economic impact on the smallholder and marginal farmers through the loss of crops due to wild animals. The majority of farmers (23%) had incurred annual household economic loss ranging from US$49-US$59 per household.

The presence of wild edible plants and determinants influencing their harvest, consumption, and conservation in south eastern Bhutan.

Wild edible plants (WEPs) grow naturally in self-maintaining ecosystems. WEPs are harvested for consumption, sale, and medicinal uses. We hypothesize that WEPs play a major role in supplying food and generating income for the rural people in a world that is increasingly recognising its emerging conservation issues. We tested this hypothesis by identifying the reasons for harvest, consumption, and conservation of WEPs using focus group discussion, field observations and questionnaire surveys in south eastern Bhutan in late 2019. Focused group discussions were held with the local people to identify reasons for harvest and consumption of WEPs. Data on the identified reasons for harvest, consumption, and conserving WEPs were determined using a questionnaire survey with ranking scales for a set of 76 randomly selected households. Representative field-observations and questionnaire surveys were carried out in villages close to forests. Parts of the plant used, how these were consumed, harvest season, and plant (life form) were recorded. The data was subjected to a Kruskal-Wallis rank sum test and weighted averages calculated. A total of 120 WEPs belonging to 63 families (including Agaricaceae) were reported. Most of the WEPs recorded were trees (45.0%) then herbs (25.8%), vines (13.3%) and shrubs (10.8%). The commonly consumed plant parts were the fruit (43.3%), shoots (28.3%) and leaves (20.8%). The purposes for harvesting and consumption, conservation of WEPs were significantly (P<0.001) different, while the motivations for collecting WEPs were not. The motivation for collecting WEPs were family consumption > sale > medicinal uses > preservation for future use > insufficient food from cultivated source's. The two most important strategies for conservation were to domesticate the WEPs and cultivate in forests. The findings reveal valuable lessons and insights about the reasons for harvesting, collection, consumption, and conservation of WEPs.

Farmers’ Perceptions of Climate Change and Its Socio-Ecological Consequences in Bhutan’s Biological Corridor Network

Sandwiched between two highly populated countries in the world, Bhutan is not an exception to the impacts of climate change. In the dearth of comprehensive climate data and limited research endeavors, Bhutan’s 69% of the total population, depending on agriculture and livestock farming, is apparently vulnerable to climate change adversities. Notably, those dwelling within the precincts of the Biological Corridors (BCs), recognized as custodians and conservation partners, have been relatively neglected in aspects of climate change impact studies. In the year 2019, our pioneering study in the northern biological corridors of Bhutan aimed to (i) comprehend people’s sensitivity to climate change; (ii) discern people’s perceptions on the severity of climate change impacts on livelihood, natural resources, and wildlife patterns; and (iii) help formulate appropriate strategies and policy transformation in climate adaptation interventions. We conducted a semi-structured questionnaire survey, applying random sampling (n = 136) of 435 households from western, central, and eastern Bhutan. Study revealed that farmers’ sensitivity and perception of the impact of climate change vary spatiotemporally, demographically, and occupationally. Not more than 76.7% of respondents noticed the changing climate patterns over the last ten years, while landless households (3%) noticed no discernible impacts. A rise in temperature is the most sensitive variable reported, followed by erratic precipitation, a change in plant phenology, and a shift in wildlife occupancy patterns. A total of 48% of respondents reported drought, scanty rain, floods, and diseases that moderately affected agriculture crops and livestock, while 42% of respondents perceive that climate change is a driving factor for human–wildlife conflict because of increasing wild animal movement towards their region. About 51% of respondents indicated adopting new adaptation strategies, which involved transitioning to different cattle breeds and altering agricultural cropping patterns and crop varieties. We recommend political support for inducing climate-smart agriculture and livestock practices. Urgent research is recommended for the shift of habitats and wildlife due to climate change to better understand and help formulate pragmatic climate adaptation measures in the face of rising human–wildlife conflict.

Analysis of the Technical Efficiency of Rice Production in Radhi Gewog, Trashigang District, Bhutan: A Stochastic Frontier Approach

Rice is the staple cereal crop in Bhutan. This paper analyzes the technical efficiency and its associated factors that influences the rice efficiency in Radhi Gewog, Trashigang District in Eastern Bhutan. Primary data on socio-economic and production function data were collected by employing stratified random sampling from 120 rice producing farmers for the year 2021-2022. The stochastic frontier parametric analysis approach was used for analyzing the objective of the paper. The results showed that rice farmers in the study area are technically efficiency at 76.4 percent. Training, size of the household and extension were found to have significant effect on maize technical efficiency.

Community-based conservation in Eastern Himalayan biodiversity hotspot- a case study

Biodiversity resources of southern bank of Yarlung Tsangbo river valley in South Tibet and Bumdelling-Tawang corridor in the eastern Bhutan are less explored by tourism and urbanization. Institutional initiatives for the conservation of these rich biodiversity areas under the traditional ownership of local communities of Arunachal Pradesh led to a community-based conservation model of Community Conserved Areas (CCA). Spontaneous participation of the stakeholders in these CCA was lacking because conservation objective was conflicting with traditional livelihood practices. To create new livelihood opportunities, the village institutions mobilized community-based leisure models and aligned these alternate livelihood objectives with ecological conservation. These economic initiatives met the challenges of bureaucratic administration, restricted access being close to international boundary with Bhutan & China, ineffective promotion by government agencies, and, the threats caused by the hydroelectric dam project. Strategy implementation was flawed because of the information sharing mechanism between China-India and India-Bhutan is constrained due to international borders. Internal challenges of indigenous CCA were limited customer integration, skewed societal acceptance of leisure-based livelihood practices, and capital cost of conservation capacity. Marketing of tourism in CCAs of Thembang and Zemithang as nature tourism destination requires all-weather road, sustained technical and financial support, and distribution linkages. This research discusses the critical success factor of Zemithang as an expanding CCA and limitations of Thembang CCA in mobilizing host community support. The authors argue that the community-based biodiversity conservation in the western Arunachal Pradesh must be supported by a participatory format of alternate livelihood opportunities.

Kyanite petrogenesis in migmatites: resolving melting and metamorphic signatures

Aluminosilicates (kyanite, sillimanite and andalusite) are useful pressure–temperature (P–T) indicators that can form in a range of rock types through different mineral reactions, including those that involve partial melting. However, the presence of xenocrystic or inherited grains may lead to spurious P–T interpretations. The morphologies, microtextural positions, cathodoluminescence responses and trace element compositions of migmatite-hosted kyanite from Eastern Bhutan were investigated to determine whether sub-solidus kyanite could be distinguished from kyanite that crystallised directly from partial melt, or from kyanite that grew peritectically during muscovite dehydration reactions. Morphology and cathodoluminescence response were found to be the most reliable petrogenetic indicators. Trace element abundances generally support petrographic evidence, but protolith bulk composition exerts a strong control over absolute element abundance in kyanite. Sample-normalised concentrations show distinctive differences between petrogenetic types, particularly for Mg, Ti, V, Cr, Mn, Fe and Ge. LA-ICP-MS element maps, particularly combined to show Cr/V, provide additional information about changing geochemical environments during kyanite growth. Most kyanite in the studied migmatitic leucosomes is of sub-solidus origin, with less widespread evidence for peritectic crystallisation. Where present, grain rims commonly crystallised directly from the melt; however, entire grains crystallised exclusively from melt are rare. The presence of kyanite in leucosomes does not, therefore, necessarily constrain the P–T conditions of melting, and the mechanism of growth should be determined before using kyanite as a P–T indicator. This finding has significant implications for the interpretation of kyanite-bearing migmatites as representing early stages of melting during Himalayan evolution.

Community Engagement in Research &amp; Policy Development: A One Health Approach to the Control of Ticks and Tick-borne Diseases in Eastern Bhutan

Summary Livestock farming plays an important role in supporting the livelihood of resource-poor subsistence farmers in Bhutan. However, ticks and tick-borne diseases (TBDs) are major constraints on livestock farming due to their negative effect on health and production. In this case study, we illustrate how we engaged communities, academic partners from the University of Calgary (UoC), and the experts and policy makers from the Royal Government of Bhutan (RGoB) to conduct research and develop policies regarding ticks and TBDs in Bhutan. The team used a transdisciplinary approach to design and conduct an active field-surveillance programme. Live ticks were collected from cattle to determine tick species diversity, infestation prevalence and geographic distribution. Habitat suitability models were also developed for four common tick species identified in Bhutan by engaging environmental modellers from UoC. Further, we conducted face-to-face interviews with 246 farmers in eastern Bhutan to understand their knowledge, management practices and perspectives on ticks and TBDs. Five genera and 13 species of ixodid ticks were identified. Despite a high level of acaricide usage among farmers, we found that the level of knowledge about ticks and TBDs was low. The research results were shared with the communities and other stakeholders to inform and initiate the development and adoption of effective tick prevention and control measures. We conclude that such collaborative research projects using an interdisciplinary approach and involving communities have huge potential to transfer research findings into policy and practice.

Collaborative Modeling and Simulation to Mitigate High-Elevation Rangeland Degradation in Eastern Bhutan

The contribution of overgrazing to high-elevation rangeland degradation is a problem across the Himalayan region, and it leads to tensions among users. In the alpine areas of eastern Bhutan, 2 communities of settled and seminomadic herders have been engaged in enduring open conflict over access to a large natural pasture. To reestablish a communication channel between these communities, a participatory modeling and simulation process was implemented with the concerned stakeholders. A training workshop on this collaborative approach and its key tools, particularly computer-assisted role-playing games, was attended by research and extension officers and was immediately followed by a field workshop attended by 6 herders from each community. The participants used their empirical knowledge to improve the relevance of the spatial distribution of the land degradation problem on the proposed game board. They also established a link between the features and rules of the role-playing game and the actual circumstances of the rangeland. The gaming sessions allowed the participants to share their respective viewpoints on the land degradation process in a nonthreatening environment. The assessment of the field workshop identified multiple effects regarding awareness of the problem, participants' confidence, colearning, and mutual trust. This intervention enabled the emergence of social capital ahead of the preparation of major development-oriented interventions in the watershed. This study demonstrates the pertinence of using simple but relevant abstract models, codesigned with their users, to mitigate tensions between parties in conflict over the use of renewable natural resources.

Experiences of Teachers in Implementing the “Education in Emergency” During COVID-19 pandemic, 2020: A Case Study in Lower Secondary School in Eastern Bhutan.

This paper reports a case study carried out in a lower secondary school in the eastern district of Bhutan on implementing the “Education in Emergency” program during the closure of schools in 2020 due to the novel COVID-19 pandemic. It investigated teachers’ experiences of how effectively they implemented the “Education in Emergency” (EiE) Programme initiated by the Ministry of Education, Bhutan through various online tools. This study employed a sequential multi-method paradigm starting with the survey of all teachers (n=35), preceded by in-depth semi-structured interviews, observations, and detailed field notes of teachers (n=6) who were purposefully selected based on the survey findings. The study focused on understanding the teachers’ awareness of the change of curriculum, students’ level of preparedness for online learning, support from various stakeholders; school, parents, and Dzongkhag Education Sector, and perceptions of teachers on the special program “Reaching the Unreached” initiated by the school solely aimed at benefiting the students who were unable to access from the e-learning platforms. The study revealed some of the barriers to effective teaching and learning such as teachers’ inadequate skills in using technological devices, lack of smart phoness or laptops, data packages, and weak internet connectivity. The study also reveals numerous positive findings, such as proactive support from schools in implementing EiE, parents' support for students’ learning and pioneering ”reaching the unreached” initiatives to support students who were not favoured by e-learning platforms. Although the school has showcased exemplary professionalism, additional improvements and modifications are required to successfully navigate the EiE.

The future of yak farming and herding culture in Bhutan: A case of the Brokpa herders of Merak and Sakteng

AbstractThis article explores the impacts of recent trends in yak farming on yak herding culture among the Brokpa of Merak and Sakteng in eastern Bhutan. It assesses the challenges experienced by herders in the context of climate variability and socioeconomic development. The data were collected through participant observation and semi‐structured interviews with 20 Brokpa in Merak and Sakteng and through analysis of livestock census records of six consecutive years (2013–2018). The results of the study reveal a number of significant issues: a labor shortage resulting from Brokpa youths leaving villages for better job opportunities, overgrazing and shrinking of rangelands, and declining yak populations due to disease and predation. In addition, study respondents worried about the unpredictable displacement of Brokpa and a possible loss of identity as a result. Unless alternative policies and interventions are adopted to ensure the sustainability of yak farming and rangelands, the future of yak herding culture is uncertain.

Effectiveness of Teachers in Relation to Leadership of Principals in Bhutan: A Case of Secondary Schools from Trashigang District

Abstract: The present study has been conducted with the purpose to explore the relationship between occupational self-efficacy of secondary school teachers and transformational leadership behavior of secondary school principals of Trashigang district in Eastern Bhutan. The study was descriptive in nature and constitute the sample of purposively selected 126 secondary school teachers and 12 secondary school principals. Published Ocupational Self-Efficacy Scale (OSES) developed by Sanjyot Pethe, Sushma Chaudhari and Upinder Dhar, (1999), and Transformational Leadership Scale, TLS-Form L-(Leader) Form developed by Dr, Surendra Nath Dubey have been used to collect the data. Investigator has computed percentage analysis, t’ test, One-Way ANOVA &amp; Chi square to test the formulated hypotheses. The findings of the study revealed that occupational self-efficacy do not correlate with transformational leadership and male and female teachers do not differ in their occupational self-efficacy. The high and lower secondary school teachers differ in their levels of occupational self-efficacy. The study also revealed that there exists no significance difference in occupational self-efficacy of teachers with respect to years of experience.