Isolation and Elucidation of Structures of Biologically Active Secondary Metabolites from Various Organisms, Including Cyanobacteria, Sponges, and Areca catechu.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017

Modeling Seed Dispersal and Population Migration Given a Distribution of Seed Handling Times and Variable Dispersal Motility: Case Study for Pinyon and Juniper in Utah

The spread of fruiting tree species is strongly determined by the behavior and range of fruit-eating animals, particularly birds. Birds either consume and digest seeds or carry and cache them at some distance from the source tree. These carried and settled seeds provide some form of distribution which generates tree spread to the new location. Firstly, we modal seed dispersal by birds and introduce it in a dispersal model to estimate seed distribution. Using this distribution, we create a population model to estimate the speed at which juniper and pinyon forest boundaries move. Secondly, we introduce a fact that bird movement occurs based on local habitat type to receive modified dispersal model. Birds can easily move many kilometers but habitat changes on the scale of tens of meters with rapidly varying. We develop a new technique to solve the modified dispersal model and approximate the form of transported seed distributions in highly variable landscapes. Using a tree population model, we investigate the rate of forest migration in variable landscapes. We show that speeds calculated using average motility of animals and mean seed handling times accurately predict the migration rate of trees. Regional scale forest distribution models are frequently used to project tree migration based on climate and geographic variables such as elevation, and regional presence-absence data. It is difficult to accurately use dispersal models based on large-scale presence-absence data, particularly for tree species dispersed by birds. The challenge is that variables associated with seed dispersal by birds are represented only few meters while the smallest pixel size for the distribution models begins with few kilometers. Transported seed distribution estimated in the variable landscape offers a tool to make use of this scale separation. Finally, we develop a scenarios that allows us to find large scale dispersal probabilities based on small scale environmental variables

Effect of intercropping on the incidence of Jassid (Amrasca biguttula biguttula Ish.) and Whitefly (Bemesia tabaci Guen.) in Okra (Abelmoschus esculentus L. Moench)

Okra is one of the most important summer vegetables in South Asian countries including Nepal. However, the damage by insects like Jassid (Amrasca biguttula Ish.) and whitefly (Bemisia tabaci Guen) has resulted in significant reduction of its production. An experiment was conducted based on intercropping taking okra (Abelmoschus exculentus L. Moench) as the main crop in Arghau, Lekhnath-27, Kaski, Nepal from March 4 to May 24, 2018. The intercrops used were coriander (Corriander sativum), carrot (Daucas carota), fennel (Foeniculum vulgare) and parsley (Petroselinum crispum). The population of jassid and whitefly was recorded from three leaves representing the different strata (bottom, middle and top) of the vegetative parts; and related yield parameters were also observed to correlate with the level of population incidence of these pests. Least numbers of jassids (5.50±0.29, 6.94±0.43, 8.00±0.41 and 3.69±0.76) were observed respectively at 30, 40, 50 and 60 days after sowing (DAS) in okra+ coriander. Likewise, okra + coriander intercropping was effective in inhibiting the population of whitefly (7.50±0.59, 8.56±0.19, 10.25±0.66 and 7.06±0.42) at 30, 40, 50 and 60 days after sowing (DAS) respectively. In contrary, the highest number of jassids and whiteflies were observed in okra + parsley and control (okra only). Both pod length (cm) and yield (t/ha) were the highest (17.92±0.57 and 28.20±0.49 respectively) in okra + coriander and were the lowest (16.42±0.21 and 27.58±0.39 respectively) in okra + carrot. The benefit-cost ratio was in order okra + coriander > okra + carrot > okra + fennel > okra + parsley > control (okra only). Among the different intercrop combinations, the okra + coriander was found most effective that could be suggested as one of the alternative strategies to limit the population of pests; jassid and whitefly in okra

Pattern of Head Injuries in Western Hilly Region of Nepal: A Hospital-based Cross-sectional Study

Introduction: Subtle or gross structural changes of scalp, skull and its contents due to application of direct or indirect external force are known as head injuries. Head being the most vulnerable and prominent part of body, injuries to it cause major mortality and morbidity globally. This study focussed to find the pattern of traumatic head injuries in patients presented to Lumbini Medical College Teaching Hospital, Palpa, Nepal. Methods: The data was collected from 252 patients (164 males and 88 females) with head injuries attending Emergency or out-patient department of Neurosurgery of the institute. All patients with traumatic head injuries (scalp injury, skull fracture, intracranial haemorrhage and brain injury) were included in the study and brought dead patients and patients with non-traumatic brain lesions were excluded. Results: Among the various modes of head injuries, the most frequent was road traffic accidents accounting 125 (49.60%) cases and fall from height 108 (42.86%) cases was second to it followed by physical assault 12 (4.76%) and others 7(2.78%). Manner of injuries were unintentional in 238 (94.44%) of cases. Among males, intentional injuries were present in 5 (2.98%) cases and among females, 9 (10.72%) cases presented with intentional injuries. In 105 (41.67%) of the cases, head injuries were associated with injuries to the other body parts as well. Conclusion: The most common cause of head injury was found to be road traffic accident followed by fall from height. Intentional injuries were more common in females when compared to males

Promoting the adoption of improved ICM technologies in chickpea by poor farmers in Nepal

Chickpea is an important source of protein in Nepal for both poor rural and urban families. Yields of legumes including chickpea have decreased in recent years, primarily due to disease and insect pest problems, and the reluctance of farmers to invest time and money in a crop which increasingly fails. This project aimed to improve, validate and evaluate a complete integrated crop management (ICM) strategy for chickpea on farms; to persuade farmers to adopt the strategy through workshops and farm trials in some of the poorest areas of Nepal; and to promote the strategy widely to the press. and other stakeholders. The improved seed and technologies offered were in high demand by farmers, and the project produced evidence to show that the outputs (increased yield of a cash crop) have been translated into significant impacts on livelihood, including improved housing, debt repayment, education costs, clothes and healthcare. The value of the improved seed has been impressive and will benefit farmers in the longer term. An innovative promotional strategy promoted the findings to policymakers as well as farmers, and used the popular media in Nepal and the UK to publicise the wor

COVID-19 Pandemic, Climate Change, and Conflicts on Agriculture: A Trio of Challenges to Global Food Security

Global food security is a worldwide concern. Food insecurity is a significant threat to poverty and hunger eradication goals. Agriculture is one of the focal points in the global policy agenda. Increases in agricultural productivity through the incorporation of technological advances or expansion of cultivable land areas have been pushed forward. However, production growth has slowed in many parts of the world due to various endemic challenges, such as decreased investment in agricultural research, lack of infrastructure in rural areas, and increasing water scarcity. Climate change adversities in agriculture and food security are increasing. Recently, the COVID-19 pandemic has severely affected global food supply chains. Economic and social instability from the pandemic contribute to long-term disturbances. Additionally, conflicts such as war directly affect agriculture by environmental degradation, violence, and breaches of national and international trade agreements. A combination of food security and climate change challenges along with increased conflicts among nations and post-COVID-19 social and economic issues bring bigger and more serious threats to agriculture. This necessitates the strategic design of policies through multifaceted fields regarding food systems. In this comprehensive review, we explore how these three challenging factors, COVID-19, climate change, and conflicts, are interrelated, and how they affect food security. We discuss the impact of these issues on the agricultural sector, plus possible ways of preventing or overcoming such adverse effects

Effect of different spacing and mulching on growth and yield of Okra (Abelmoschus esculentus L.) in Chitwan, Nepal

Okra (Abelmoschus esculentus L.) is one of the most important vegetable crop of Nepal. Its yield and growth parameters are affected by different cultural practices. This study was conducted at Olericulture Farm of Agriculture and Forestry University, Rampur, Chitwan, Nepal during April 29 to July 9 of 2018. The field experiment was carried out in split plot design using three replications. The treatments consisted of three intra row spacing (30, 45 and 60 cm) and four different mulching materials (Silver plastic, Panicum repens, Lantana camara and bare soil). The objective of this experiment was to assess the effects of various intra-row spacings and mulching materials on growth and yield of okra. The effect of mulching materials on okra yield was found significant. The okra yield was highest (8104 kg/ha) under silver plastic mulch followed by control (5161kg/ha), Panicum repens (3901kg/ha) and Lantana camera (3701kg/ha), respectively. Silver plastic mulch enhanced the growth parameters like canopy length, plant height, leaf number, leaf length, girth and yield of okra. The spacings provided non significant effect on okra yield, however the yield of okra was highest (7295 kg/ha) under 30×30 cm spacing followed by 45×30 cm (4660 kg/ha) and 60 cm × 30 cm spacing (3703 kg/ha), respectively. Combination of silver plastic mulch along with 30 cm × 30 cm spacing provided the highest okra yield. This study suggests that farmers of the Chitwan should grow okra at spacing of 30 cm × 30 cm and under silver plastic mulch to produce higher yield

Effects of different fertilizers on the growth and yield of okra (Abelmoschus esculentus L.) in summer season in Chitwan, Nepal

An experiment was conducted in the Horticulture Farm of Agriculture and Forestry University to demonstrate the effects of different fertilizers on the yield and yield parameters of okra (var. Arka Anamika). The experiment was laid out in Randomized Complete Block Design (RCBD) consisting of seven treatments and three replications. The various treatments used in the experiment were goat manure, sesame cake, mustard cake, synthetic fertilizer (NPK), poultry manure, vermicompost and untreated control. The required dose of nitrogen was fulfilled by the fertilizer itself whereas insufficient amount of phosphorous and potassium was fulfilled by addition of single super phosphate and muriate of potash respectively. The fertilizers were applied on the basis of recommendation given by the Nepal Agriculture Research Council (NARC). The effect of poultry manure on number of open flowers and number of fruits at 40 DAS was found superior. The effect of poultry manure on plant height, number of leaves, plant diameter was found superior at 50 DAS. Goat manure produced the superior result on number of open flowers at 50 DAS. Poultry manure on the number of leaves and plant height produced the significant result at 60 DAS. Synthetic fertilizer responded well to number of fruits at 60 DAS. Sesame cake produced the superior results at 70 DAS on number of buds. Poultry manure responded well to all the parameters and produced the yield of 200 qt./ha with the BC ratio of 1.77. This experiment suggests the farmers to use the poultry manure to get the highest economic return. Vermicompost and mustard cake producing the superior and significant yield in this research are not recommended as they have low BC ratio unless effective measures are encouraged to reduce the cost of this fertilizers

Characterizing a Shallow Groundwater System beneath Irrigated Sugarcane with Electrical Resistivity and Radon (222Rn), Puunene, Hawai

In this study, we use a combination of electrical resistivity profiling and radon (222Rn) measurements to characterize a shallow groundwater system beneath the last remaining, largescale sugarcane plantation on Maui, Hawaii. Hawaiian Commercial & Sugar Company has continuously operated a sugarcane plantation on the western flank of Haleakala Volcano since 1878. The sugarcane is irrigated with a combination of surface water brought through tunnels from the wetter, eastern flank of Haleakala Volcano and groundwater from wells within the plantation. To assess the flow of irrigation water through the shallow subsurface, we collected a representative topo-sequence of four 2-D resistivity profiles that sample different topographic and hydrologic settings within the plantation. The profiles show a down-slope-thickening (0 to 20 m), surficial low-resistivity (10-200 Ohm-m) layer extending from the upslope limit of irrigated sugarcane to the lowest elevations of the plantation. At a canal crossing, the low resistivity layer thickens and is less resistive upslope of the canal. Beneath a reservoir at midelevation, the layer thickens to 20 m and curves down slope beneath the reservoir and up to the base of the field beyond. At the base of the slope, the low resistivity layer is 20-m thick below both fields and a second reservoir. An increase in radon concentration in the down-flow direction within the canal system at one location suggests groundwater infiltration into the canal. We attribute the low-resistivity layer to irrigation water that has infiltrated below the root zone and leaked from canals and reservoirs within the plantation. The water flows down slope to the base of the slope and there flows vertically, recharging the basal aquifer. We suggest that seepage from the canals and reservoirs is in part controlled by the local pressure head within the shallow flow system