Oriented Zinc Oxide Nanocrystalline Thin Films Grown from Sol-Gel Solution

Zinc oxide (ZnO) is a wide band gap (~3.37 eV) semiconductor. Thin film ZnO has many attractive applications in optoelectronics and sensors. Recently, nanostructured ZnO (e.g. ZnO quantum dot) has been demonstrated as a hyperbolic material; its dielectric function has opposite signs along different crystal axes within the mid-infrared, making it an interesting material for metamaterials and nanophotonics. Conventional sputtering deposition usually leads to the formation of polycrystalline ZnO films with randomly oriented grains and rough surface. This work demonstrated a solution-based process to grow ZnO thin films with highly oriented nanocrystals. Low-temperature plasmas were employed to modulate the microstructure and optical properties of the films. Such highly anisotropic nanostructured transparent semiconductor films may lead to interesting material properties in developing new optoelectronic devices

Global lessons from successful rhinoceros conservation in Nepal

Global populations of rhinoceros have declined alarmingly, from about 500,000 at the beginning of the 20th century to 29,000 in 2016, largely due to an escalation of poaching for rhinoceros horn (Traffic 2016; Biggs et al. 2013). The current global rhino population is comprised of three Asian Species and two African species, the latter located in South Africa, Kenya, Tanzania, Namibia and Zimbabwe,. In Africa, the Southern white rhinoceros population is estimated at 20,700; and there are estimated to be around 4,885 black rhinoceros. The greater one-horned rhinoceros, found in Nepal and India, has a population of approximately 3,555. The other Asian rhino species are confined to Indonesia and have much lower numbers; there are fewer than 100 Sumatran rhinos and only 58–61 Javan rhinos. The number of African rhino killed by poachers in the last ten years is estimated at 5,957 (Traffic 2016; Emslie et al. 2013; Poaching fact2016), about 1,338 of these were taken in 2015, a year in which the highest number of rhino were taken since the late 1980s (Traffic 2016; Gaworecki 2016; Figure 1). At current poaching rates, Africa’s rhino populations may be extinct within 20 years (Di Minin et al. 2015). The Sumatran and Javan rhino populations continue to decline due to habitat destruction, poaching and inbreeding (Save the Rhino, 2016b) pushing them to the verge of extinction

Is trophy hunting of bharal (blue sheep) and Himalayan tahr contributing to their conservation in Nepal?

Dhorpatan Hunting Reserve (DHR), the only hunting reserve in Nepal, is famous for trophy hunting of bharal or ‘blue sheep’ (Pseudois nayaur) and Himalayan tahr (Hemitragus jemlahicus). Although trophy hunting has been occurring in DHR since 1987, its ecological consequences are poorly known. We assessed the ecological consequences of bharal and Himalayan tahr hunting in DHR, and estimated the economic contribution of hunting to the government and local communities based on the revenue data. The bharal population increased significantly from 1990 to 2011, but the sex ratio became skewed from male-biased (129 Male:100 Female) in 1990 to female-biased (82 Male:100 Female) in 2011. Similarly, a recent survey of Himalayan tahr showed that there was a total population of 285 tahr with a sex ratio of 60 Male: 100 Female. Bharal and Himalayan tahr trophy hunting has generated economic benefits through generation of local employment and direct income of $364072 during the last five years. Government revenue collected from 2007-08 to 2011-12 totalled$184372. Male-focused trophy hunting as practiced in DHR may not be an ecologically sustainable practice, because its effect on the sex ratio that lead to negative consequences for the genetic structure of the population in the long term. Therefore, the population dynamics and sex ratios of the bharal and tahr must be considered while setting harvest quotas

Noninvasive genetic population survey of snow leopards (Panthera uncia) in Kangchenjunga conservation area, Shey Phoksundo National Park and surrounding buffer zones of Nepal

<p>Abstract</p> <p>Background</p> <p>The endangered snow leopard is found throughout major mountain ranges of Central Asia, including the remote Himalayas. However, because of their elusive behavior, sparse distribution, and poor access to their habitat, there is a lack of reliable information on their population status and demography, particularly in Nepal. Therefore, we utilized noninvasive genetic techniques to conduct a preliminary snow leopard survey in two protected areas of Nepal.</p> <p>Results</p> <p>A total of 71 putative snow leopard scats were collected and analyzed from two different areas; Shey Phoksundo National Park (SPNP) in the west and Kangchanjunga Conservation Area (KCA) in the east. Nineteen (27%) scats were genetically identified as snow leopards, and 10 (53%) of these were successfully genotyped at 6 microsatellite loci. Two samples showed identical genotype profiles indicating a total of 9 individual snow leopards. Four individual snow leopards were identified in SPNP (1 male and 3 females) and five (2 males and 3 females) in KCA.</p> <p>Conclusions</p> <p>We were able to confirm the occurrence of snow leopards in both study areas and determine the minimum number present. This information can be used to design more in-depth population surveys that will enable estimation of snow leopard population abundance at these sites.</p

Photovoltaic & Photophysical Study of Dye and TiO₂-nanoparticle Interactions in Porphyrin-sensitized Solar Cells

Dye sensitized solar cells (DSCs) are an inexpensive alternative to silicon cells due to inexpensive raw materials and simple design. Dye sensitized solar cells using TiO2 nanoparticles coated with Ru-complex dyes have limited efficiency due to recombination at TiO2 grain boundary defects, while Ru-complex dyes are expensive and toxic. TiO2 nanotube films sensitized by low-cost and simple porphyrin dyes can be an alternative to traditional DSCs. Another cost effective solution may be to use polycrystalline silicon thin film crystallized by flash lamp annealing (FLA) on low-cost substrates. However, a better understanding of the composition and opto-electronic properties of these materials is needed. The objectives of this research were to fabricate and characterize the optical and electrical properties of TiO2 nanotube arrays for DSCs; investigate composition of PECVD flash lamp annealed and vacuum thermal annealed silicon films; and characterize sputtered silicon films annealed by flash lamp and compare with PECVD silicon films. TiO2 nanotubes were grown by electro-chemical anodization and attached to glass substrates and studied with three porphyrin dyes. Silicon films were deposited b