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481.
People’s livelihood in several Himalayan regions largely depends on collection, use, and trade of medicinal plants. Traditional
use is generally not a problem, but commercial gathering of selected species to meet increasing national and international
demand can result in over-exploitation. Sustainable management of medicinal plants requires a clear understanding of the respective
roles, responsibilities and viewpoints of the various stakeholders involved. Through personal interviews and group discussions,
this study aimed at investigating the views of two stakeholder groups on use, trade and conservation of medicinal plants in
the Rasuwa district of Nepal. Local people and district and national organizations agreed that medicinal plants are collected
for a combination of commercial and personal uses. Perceptions on market availability differed significantly: 100 % of the
respondents from district and national organizations saw markets as easily available, against only 36 % for local people.
This could explain why medicinal plants were perceived by local people to contribute less to income generation than to livelihood
improvement. Different viewpoints were also expressed concerning the status of medicinal plants in the district: 81 % of the
respondents from district and national organizations considered that medicinal plants were threatened, compared to only 28
% for local people. Despite this disparity, both stakeholder groups agreed upon potential threats to medicinal plants: over-harvesting;
habitat loss due to land-use change and deforestation; and over-grazing by livestock. Several challenges were identified regarding
sustainable management of medicinal plants, such as ambiguous policies; lack of resources, information and infrastructures;
habitat degradation; and over-exploitation. Despite these challenges, respondents agreed that the medicinal plants sector
offers huge opportunities in the Rasuwa district, given resource availability, community awareness and motivation, and the
priority given to the sector by governments and other agencies. Proper collaboration, communication and coordination among
stakeholders are needed to grab these opportunities. 相似文献
482.
Soil and water conservation measures improve soil carbon sequestration and soil quality under cashews 总被引:2,自引:1,他引:1
Gopal Ramdas Mahajan Bappa Das Sandrasekaran Manivannan Begur Lakshminarasimha Manjunath Ram Ratan Verma Sujeet Desai Rahul Mukund Kulkarni Ashish Marotrao Latare Reshma Sale Dayesh Murgaonkar Kiran Puna Patel Shaiesh Morajkar Ashwini Desai Natasha Barnes Heena Mulla 《国际泥沙研究》2021,36(2):190-206
Land degradation is becoming a serious problem in the west coast region of India where one of the world's eight biodiversity hotspots,the‘Western Ghats’,is present.Poor land management practices and high rainfall have led to increasing problems associated with land degradation.A long-term(13-year)experiment was done to evaluate the impact of soil and water conservation measures on soil carbon sequestration and soil quality at three different depths under cashew nut cultivation on a 19%slope.Five soil and water conservation measures-continuous contour trenches,staggered contour trenches,halfmoon terraces,semi-elliptical trenches,and graded trenches all with vegetative barriers of Stylosanthes scabra and Vetiveria zizanoides and control were evaluated for their influence on soil properties,carbon sequestration,and soil quality under cashews.The soil and water conservation measures improved significantly the soil organic carbon,soil organic carbon stock,carbon sequestration rate and microbial activity compared to the control condition(without any measures).Among the measures tested,continuous contour trenches with vegetative barriers outperformed the others with respect to soil organic carbon stock,sequestration rate,and microbial activity.The lower metabolic quotient with the measures compared to the control indicated alleviation of environmental stress on microbes.Using principal component analysis and a correlation matrix,a minimum dataset was identified as the soil available nitrogen,bulk density,basal soil respiration,soil pH,acid phosphatase activity,and soil available boron and these were the most important soil properties controlling the soil quality.Four soil quality indices using two summation methods(additive and weighted)and two scoring methods(linear and non-linear)were developed using the minimum dataset.A linear weighted soil quality index was able to statistically differentiate the effect of soil and water conservation measures from that of the control.The highest value of the soil quality index of 0.98 was achieved with continuous contour trenches with a vegetative barrier.The results of the study indicate that soil and water conservation measures for cashews are a potential strategy to improve the soil carbon sequestration and soil quality along with improving crop productivity and reducing the erosion losses. 相似文献
483.
Som Pal Singh O. P. Bishnoi Ram Niwas Mahender Singh 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):93-96
An experiment was conducted during 1996–97 and 1997–98 to study spectral indices and their relationships with grain yield of wheat. Variations of ratio vegetation index (RVI), normalized differences vegetation index (NDVI). difference vegetation index (DVI), transformed vegetation index (TVI), perpendicular vegetation index (PVI) and greenness vegetation index (GVI) have been studied at anthesis stage under different moisture and nitrogen levels. Spectral indices were correlated with crop parameters and it was found that GVI was the best index for yield estimation (r = 0.91 ). 相似文献
484.
The quasisimilar theory is used to investigate the solution of the blast wave problem with generalized geometries in a non-ideal
gas satisfying the equation of state of the Van der Waals type. Here it is assumed that the distribution of normalized velocity,
pressure and density are nearly similar in the narrow range of the shock strength. A comparison between approximate analytical
solution and numerical solution of the problem is presented for the cylindrical geometry. The numerical solutions are presented
for the generalized geometry in a non-ideal gas. It is also assessed as to how the non-idealness of the gas affects the behavior
of the flow parameters. 相似文献
485.
We consider the modified restricted three body problem with power-law density profile of disk, which rotates around the center
of mass of the system with perturbed mean motion. Using analytical and numerical methods, we have found equilibrium points
and examined their linear stability. We have also found the zero velocity surface for the present model. In addition to five
equilibrium points there exists a new equilibrium point on the line joining the two primaries. It is found that L
1 and L
3 are stable for some values of inner and outer radius of the disk while other collinear points are unstable, but L
4 is conditionally stable for mass ratio less than that of Routh’s critical value. Lastly, we have studied the effects of radiation
pressure, oblateness and mass of the disk on the motion and stability of equilibrium points. 相似文献
486.
We have carried out deep (V ∼ 21 mag) UBVRI photometric study of the star cluster Stock 18. These along with archival Infrared data have been used to derive the basic cluster parameters and also to study the star formation processes in and around the cluster region. The distance to the cluster is derived as 2.8 ± 0.2 kpc while its age is estimated as 6.0 ± 2.0 Myr. Present study indicates that interstellar reddening is normal in the direction of the cluster. The mass function slope is found to be −1.37 ± 0.27 for the mass range 1 < M/M⊙ < 11.9. There is no evidence found for the effect of mass segregation in main-sequence stars of the cluster. A young stellar population with age between 1-2 Myr have been found in and around the cluster region. The presence of IRAS and AKARI sources with MSX intensity map also show the youth of the Sh2-170 region. 相似文献
487.
Arun K. Gupta Sumer Chopra Sanjay K. Prajapati Anup K. Sutar B. K. Bansal 《Natural Hazards》2013,68(2):405-417
In this study, we have prepared an intensity map based on macroseismic survey and all the available information from print and electronic media of damage and other effects due to March 05, 2012, M 4.9 Bahadurgarh (Haryana–Delhi border) earthquake and interpreted them to obtain modified Mercalli intensities (MMI) at over 62 locations surrounding the Haryana and Delhi. We have cross-checked the damage information from print and electronic media in the field at 25 sites within 110 km surrounding the epicenter for validation. Based on the questionnaire which is used in macroseismic survey and personal judgment, intensities were assigned accordingly as per physical survey at 25 sites and for rest based on media reporting. A maximum intensity of VI was assigned to this seismic event. Isoseismals of V and VI have been fully covered in the field observations. Beside this, some of the points have also been covered for isoseismal IV and isoseismal III and rest are based on media report only. The intensity map reveals several interesting features. Elliptically elongated shape of intensity map shows that most of the slightly damaged areas are concentrated toward the northwestern side of the epicenter having intensity V which may be due to directivity or site effects. A regression relation has also been derived between intensity and epicentral distance. The derived attenuation relation will be useful for assessing damage of a potential future earthquake (earthquake scenario–based planning purposes) for the Delhi NCR region. 相似文献
488.
N. Divya A. Bansal A. K. Jana 《International Journal of Environmental Science and Technology》2013,10(6):1265-1274
During dyeing process, industries consume large quantity of water and subsequently produce large volume of wastewater. This wastewater is rich in color and contains different dyes. Orange II is one of them. In this article, metal-impregnated TiO2 P-25 catalyst was used to enhance the photocatalytic degradation of Orange II dye. Photodegradation percentage was followed spectrophotometrically by the measurements of absorbance at λ max = 483 nm. The effect of copper-impregnated TiO2 P-25 photocatalyst for the degradation of Orange II has been investigated in terms of percentage removal of color, chemical oxygen demand (COD) and total organic carbon (TOC). As such 98 % color removal efficiency, 97 % percentage removal of COD and 89 % percentage removal of TOC was achieved with TiO2 P-25/Cu catalysts under typical conditions. Copper-impregnated TiO2 P-25 photocatalyst showed comparatively higher activity than UV/H2O2 homogeneous photodegradation. The relative electrical energy consumption for photocatalytic degradation was considerably lower with TiO2 P-25/Cu photocatalyst than that with homogeneous photodegradation. Transmission electron microscopic analysis was used for catalyst characterization. 相似文献
489.
490.
Two‐dimensional nonlinear diffusive numerical simulation of geomorphic modifications to cinder cones
The temporal evolution of simple landforms such as cinder cones by nonlinear diffusive processes is studied through the use of a new 2D numerical model using well‐established and accurate numerical mathematics and high‐resolution digital elevation models (DEMs). Extending 1D (profile) nonlinear diffusion analyses used in cinder cone, hillslope and fault scarp evolution studies, we have implemented a 2D numerical model with a spatially and temporally varying sediment transport rate coefficient scaled nonlinearly by the ratio of local slope to critical slope. The high accuracy and efficient numerical implementation are documented in the paper and the MATLAB toolkit developed is used to solve for the developmentof an initial 2D cone form. First, we examine the nonlinear transport rule and suggest a refinement that accounts explicitly for flux at threshold slopes. We find that the maximum diffusion (necessarily introduced in the numerical model to avoid infinite rates) at the critical slope controls the final morphology, especially approaching steady state. Secondly, solving the landscape evolution problem in 2D enables a natural accounting for sediment flux convergence or divergence in the profile. Thirdly, the boundary behavior of a given landscape element controls much of what happens in that domain and so we allow for arbitrary flux magnitude or elevation boundary conditions. Fourthly, landscapes are heterogeneous in their surface cover and so we allow for spatially and temporally varying transport rate k and we permit an arbitrary vertical displacement field within the model domain. To test the new formulation for the nonlinear term, the effect of variable diffusivity k and the numerical schemes implemented, we apply the model to cinder cones built on the flanks of Mount Etna in 2001 and 2002–2003. We explore the effects of DEM resolution with data from the 2001 cone and the utility of spatially variable diffusivity to explain the variation in erosion measured by differencing repeat light detection and ranging (LIDAR) surveys gathered in 2004 and 2007 over the 2002–2003 cone complex. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献