Role of non-timber forest products in sustaining forest-based livelihoods and rural households' resilience capacity in and around protected area- a Bangladesh study

People in developing world derive a significant part of their livelihoods from various forest products, particularly non-timber forest products. This article attempts to explore the contribution of NTFPs in sustaining forest-based rural livelihood in and around a protected area of Bangladesh, and their potential role in enhancing households resilience capacity. Based on empirical investigation our study revealed that, local communities gather a substantial amount of NTFPs from national park despite the official restrictions. 27 percent households of the area received at least some cash benefit from the collection, processing and selling of NTFPs, and NTFPs contribute as HHs primary, supplementary and emergency sources of income. NTFPs also constituted an estimated 19 percent of HHs net annual income, and were the primary occupation for about 18 percent of the HHs. HHs dependency on nearby forests for various NTFPs varied vis-a-vis their socio-economic condition as well as with their location from the park. Based on our case study the article also offers some clues for improving the situation in PA.Comment: To appear in Journal of Environmental Planning and Management, 201

Graphene Based Heterojunctions for Nano-Electronic and Sensing Applications

Graphene, an atomically thin and semi-metallic two dimensional material, has been extensively researched over the past decade due to its superior intrinsic carrier velocity, electrical and chemically tunable work function, ability to form layered heterostructure with other materials, and relevant potential applications in electronics, sensing, optoelectronics, energy storage, etc. However, the confinement of charge carriers within one atomic layer results in an electrical transport that is extremely sensitive to the surrounding environment, which is beneficial for sensing applications, but at times unfavorable for electronic applications due to scattering from extrinsic impurities. In addition, due to its rather delicate structure, engineering a high quality gate dielectric without altering its characteristic electronic structure while enabling optimal surface passivation and gate control is one of the major challenges for graphene device development. Hexagonal Boron Nitride (hBN) has emerged as a possible option to meet the challenges, and has been exploited to alter graphene electronic structure by intentional crystallographic misalignment between the layers at the time of transfer or synthesis. The variation in electronic structure by hBN is possible due to its unique properties such as inert surface, similar hexagonal and nearly lattice matched structure with graphene and high surface optical phonon modes. Low temperature Pulsed laser deposition (PLD) grown amorphous BN on SiO2/Si, phase transformed to hBN by forming gas annealing, has been employed for graphene device application. Graphene field effect transistor (FET) fabricated from layered heterostructure of graphene/hBN on SiO2/Si exhibited electrical performance enhancement over graphene on SiO2/Si substrate in terms of mobility, carrier inhomogeneity and extrinsic doping. In a parallel effort, taking advantage of graphene’s tunable work function, a novel genre of sensor based on noble metal nanoparticle functionalized graphene/Si heterojunction Schottky diode has been developed for sensing non-polar H2, and enhancing response for polar NH3 molecular species. Reverse bias operation of the diode sensor exhibited orders of magnitude higher response compared to graphene FET based sensors due to exponential change in reverse current originated from interface barrier height change. The reverse bias operation also allows low power operation and modulation of the Fermi level of graphene, which can lead to the tuning of sensitivity and expansion of the dynamic range. Impedance Spectroscopic analysis of the diode sensor has been carried out to understand the underlying current transport mechanism. Fitting the impedance spectra for different gaseous exposure conditions with an equivalent circuit model, the changes in junction resistance and capacitance have been extracted. Along with these two parameters, experimentally obtained 3-dB cut off frequency for each gas exposure has been utilized for multimodal sensing by the diode sensor. Finally, temperature dependent magneto-transport study of PdHx passivated graphene has been carried out to elucidate the effect of metal nanoparticle assisted doping and molecular adsorption on graphene electrical transport properties. It has been observed from the systematic study that, the dominant scattering mechanism in bilayer graphene switched from coulomb scattering to thermal excited surface optical phonon scattering after PdHx passivation, and Hall mobility exhibited significant enhancement at the measurement temperature range of 298 to 10 K. Due to recent interests in exploiting metallic nanoparticles as dopant for 2D crystals, as well as enhancing sensitivity of chemical sensors and photodetectors, the findings are significant and would pave the way for future research efforts in this area

Three Essays on International Trade and Finance

This dissertation is composed of three essays at the intersection of international trade and finance. In the first chapter, I measure exchange rate pass-through (ERPT) for value-added exports, where intermediate input requires sharing among countries in a back-and-forth manner for producing a single final product. I derive an estimating equation for ERPT and value-added trade following a partial equilibrium model, which also leads to decomposition of the trade elasticity into the own price effect and the price index effects. From the empirical estimation, I find that ignoring the value-added trade will cause a systematic upward bias in the estimation of ERPT. I also find that there exists substantial heterogeneity in pass-through rates across sectors: sectors with high-integration into global markets functions with a lower rate of exchange in comparison to sectors with less integration. The second essay focuses on a specific market, where I examine the relationship between product attributes and ERPT. This paper estimates the ERPT by using good-level daily data on wholesale prices of imported agricultural products, where the identification is achieved by using daily data on the domestic inflation rate. The results of standard empirical analyses are in line with existing studies that employ lower frequencies of data by showing evidence for incomplete daily ERPT of about 5 percent. The key innovation is achieved when nonlinearities in ERPT are considered, where ERPT is doubled to about 10 percent when daily nominal exchange rate changes are above 0.55 percent, daily frequencies of price change are above 3.12 percent, the storage life of a product is above 10 weeks, and for the non-zero price changes, the ERPT is complete. In the final essay, I focus on the firms’ export pricing strategy: pricing-to-market strategy. To achieve this, I introduce a partial equilibrium model of firm’s pricing strategy, where the market share of a firm plays an important role in the determination of markup. The empirical estimation is that markup ranges from 1.25 to 1.5 across years and 1.25 to 51.23 across firms. I also find that markups come back to their average level within 30 to 60 days of the initial date

DETERMINING INTERSTELLAR REDDENING: A NEW APPROACH USING SPECTROSCOPY AND PHOTOMETRY

The mystery of Canis Major overdensity is addressed. We discuss concurrent methods and their limitations on the determination of interstellar reddening. We establish a new way to determine line of sight interstellear reddening by observing stellar spectral lines and UBV colors. We observe and analyze spectra of 22 stars in different open clusters. We find that Hydrogen Balmer line at 4861 angstrom can predict the stellar atmospheric parameters and intrinsic colors with reasonable accuracy. Comparing with observed colors we derive the reddening of the stars. We compare our results with standard database WEBDA and find that within 90% probability limit the standard deviation of the error is 0.102798. This is improved by taking the absolute maximum probabilities and the scatter becomes 0.0688865