717 research outputs found
EFFECTS OF LAND-USE CHANGE ON THE PROPERTIES OF TOP SOIL OF DECIDUOUS SAL FOREST IN BANGLADESH
This study examined the effects of land use change on the physico-chemical properties of top soil in the deciduous Sal forest of Bangladesh. Relatively less disturbed Sal (Shorea robusta Roxb. Ex Gaertn.) forest stands and the nearby stands those were converted into Acacia (Acacia auriculiformis Benth.) plantation and pineapple (Ananus comosus (L.) Merr.) cultivation were selected to examine the effects of land use change on soil properties. For each land use type, soil samples were collected from 4 locations, 50m distant from each other, as replicates. Soil samples were collected at 0-5, 5-10, and 10-15 cm depths. Soil moisture content, conductivity, pH organic C, total N and total P were determined as soil properties. Leaf litter of Sal, Acacia and pineapple was incubation for 90 and 180 days in independent identical soil in order to examine the effects of plant species through leaf litter on the soil chemical nutrient (N and P) status. Data showed that soil moisture content, conductivity and pH were significantly affected by land use but not by depth. However, soil organic C was affected by both land-use type (P< 0.02) and soil depth (P< 0.003), although no significant interactions appeared between these two factors. Soil total N and P did not differ between land use types but by depth and, N and P contents decreased with the increase of depth. Rates of nutrients (N and P) released from Sal, Acacia and pineapple did not differ significantly among them during incubation. Results of the present study reveal that properties of the top soil of the Madhupur Sal forest are different in their responses to the varying land uses. The findings of this study are thus relevant for the sustainable management of the deciduous Sal forest ecosystems
Distinguishing Posed and Spontaneous Smiles by Facial Dynamics
Smile is one of the key elements in identifying emotions and present state of
mind of an individual. In this work, we propose a cluster of approaches to
classify posed and spontaneous smiles using deep convolutional neural network
(CNN) face features, local phase quantization (LPQ), dense optical flow and
histogram of gradient (HOG). Eulerian Video Magnification (EVM) is used for
micro-expression smile amplification along with three normalization procedures
for distinguishing posed and spontaneous smiles. Although the deep CNN face
model is trained with large number of face images, HOG features outperforms
this model for overall face smile classification task. Using EVM to amplify
micro-expressions did not have a significant impact on classification accuracy,
while the normalizing facial features improved classification accuracy. Unlike
many manual or semi-automatic methodologies, our approach aims to automatically
classify all smiles into either `spontaneous' or `posed' categories, by using
support vector machines (SVM). Experimental results on large UvA-NEMO smile
database show promising results as compared to other relevant methods.Comment: 16 pages, 8 figures, ACCV 2016, Second Workshop on Spontaneous Facial
Behavior Analysi
Flushing History as a Hydrogeological Control on the Regional Distribution of Arsenic in Shallow Groundwater of the Bengal Basin
Whereas serious health consequences of widespread consumption of
groundwater elevated in As have been documented in several South Asian
countries, the mechanisms responsible for As mobilization in reducing
aquifers remain poorly understood. We document here a previously unrecognized
and consistent relationship between dissolved As concentrations in
reducing groundwater and the phosphate-mobilizable As content of aquifer
sediment for a set of precisely depth-matched samples from across
Bangladesh. The relationship holds across nearly 3 orders of magnitude
in As concentrations and suggests that regional as well as local patterns
of dissolved As in shallow groundwater are set by the solid phase
according to a remarkably constant ratio of ∼250 μg/L
dissolved As per 1 mg/kg P-mobilizable As. We use this relationship
in a simple model of groundwater recharge to propose that the distribution
of groundwater As in shallow aquifers of the Bengal Basin could primarily
reflect the different flushing histories of sand formations deposited
in the region over the past several thousand years
DEVELOPMENT OF ENVIRONMENTAL MANAGEMENT PLAN (EMP) FOR OIL AND GAS EXPLORATION ALONG THE COASTAL AREAS OF BANGLADESH
The Coastal and Marine zones of Bangladesh comprise a rich and complex mix of ecosystems and natural resources. Human activities in the area include agriculture, aquaculture, salt production, industrial fishing, port and navigation activities. Hydrocarbon exploration is a new introduction to the existing human activities that impact upon the natural environment. Complexities of human interactions with the environment should be properly understood in developing the environmental management plan (EMP) for sustainable development of the resources. For completing this study three questionnaire surveys were conducted, one among local community (stakeholders), second one among peoples conducting exploration activities (mining engineers, GIS specialists, geologists and related key persons) and another among environmental experts (i.e. environmental scientists, environmental engineers, ecologists, biologists, chemists, forest officers, NGO workers, university teachers and others related academicians). From survey findings it is found that most of the local people have no clear idea about exploration program and its associated impacts but when informed, they feel the need for preparation of an extensive EMP and its proper implementation. However they have expressed their confusion about compensation system concerning the project. About 36% of people are not satisfied with existing damage compensation system. A great controversial thinking was found from their perception. A large no of people (90%) think that the distance of exploration sites of block-5 from the Sundarbans is not sufficient to protect highly sensitive mangrove ecosystem. Several environmental experts are not agreed with the exploration program along coastal blocks due to considering the vulnerability of the Sundarbans, shrimp ghers, other fisheries resources, forest and agricultural plantation, wildlife, biodiversity and other adverse impact on local people as well as possibility of firing accident. However they predict adverse environmental impacts of such projects and delineate the needs for preparation and effective implementation of an all-embracing EMP. They also outline a strategic EMP for exploration and production activities along coastal areas
Long-lasting XUV activation of helium nanodroplets for avalanche ionization
We study the dynamics of avalanche ionization of pure helium nanodroplets
activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense
near-infrared (NIR) pulse. In addition to a transient enhancement of ignition
of a nanoplasma at short delay times ~fs, long-term activation of the
nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics
simulations suggest that the short-term activation is caused by the injection
of seed electrons into the droplets by XUV photoemission. Long-term activation
appears due to electrons remaining loosely bound to photoions which form stable
`snowball' structures in the droplets. Thus, we show that XUV irradiation can
induce long-lasting changes of the strong-field optical properties of
nanoparticles, potentially opening new routes to controlling
avalanche-ionization phenomena in nanostructures and condensed-phase systems
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