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981.
Within the engineering profession and natural sciences, vulnerability is widely accepted to be defined as the degree of loss
(or damage) to a given element or set of elements within the area affected by a threat. The value of vulnerability is expressed
nondimensionally between 0 and 1. It is a fundamental component in the evaluation of landslide risk, and its accurate estimation
is essential in making a reasonable prediction of the landslide consequences. Obviously, vulnerability to landslides depends
not only on the characteristics of the element(s) at risk but also on the landslide intensity. This paper summarizes previous
research on vulnerability to landslides and proposes a new quantitative model for vulnerability of structures and persons
based on landslide intensity and resistance of exposed elements. In addition, an approximate function is suggested for estimating
the vulnerability of persons in structures. Different methods for estimating the vulnerability of various elements to slow
or rapid landslides are discussed. Finally, the application of the new model is illustrated through an example. 相似文献
982.
Role of selected riparian herbs in reducing soil erosion and nutrient loss under simulated rainfall 总被引:1,自引:2,他引:1
The native riparian herbs such as Leonotis nepetaefolia (L.) R. Br., Cassia tora L., Ageratum conyzoides L., Parthenium hysterophorus L. and Sida acuta burm f., dominant on the bank of River Damodar in Eastern Jharia Area, Dhanbad (India), were selected to assess experimentally
their quantitative role in conserving the soil and reducing water runoff and nutrient (N and P) losses. A total of 42.5 mm
simulated rainfall were applied at 30 cm h−1 rain intensity on both vegetated and bare plots. The collected runoff water and eroded soil from each plot were determined
in terms of soil, water and nutrient conservation value (CV). Among the vegetated plots, soil CV ranged from 30 to 85% and
water CV from 20 to 48%. Nutrient (N and P) CV varied from 22 to 65% for total-N, 48 to 80% for ammonia-N and 50 to 86% for
nitrate-N. CV for total-P varied from 40 to 62%, inorganic-P from 42 to 60% and organic-P from 20 to 58%. In a stepwise multiple
regression equation comprising four independent variables (canopy cover, litter mass, soil moisture and plant biomass), canopy
cover explained 70–88% (P < 0.01) of variability in conserving soil, water and nutrient. The losses through runoff water and eroded soil from vegetated
plots were found to be minimized to a great extent as compared to bare plots. The role of these species in maintaining the
texture and fertility status of riparian soil is discussed. 相似文献
983.
Jun-De Dong Yan-Ying Zhang Si Zhang You-Shao Wang Zhi-Hao Yang Mei-Lin Wu 《Environmental Earth Sciences》2010,60(8):1673-1682
A large data set obtained by a 1-year monthly determination of water quality from Sanya Bay, South China Sea, was treated
by three-way principal component analysis aimed at exploring the spatial and temporal patterns of water quality in Sanya Bay.
Tucker3 model of optimum complexity (2, 2, 1) explaining 33.18% of the data variance, allowed interpretation of the data information
in three modes. The model explained spatial and temporal variation trends in terms of water quality variables during the study
period. Water quality in sampling station (S2) Sanya River was mainly influenced by Sanya River, and water quality in other
stations (S1, S3–S10) were mainly influenced by the waters in South China Sea. The results delineated the mouth of Sanya River
as critical from pollution point of view. The dry season from October to the next April and rainy season from May to September
have different influences on water quality in Sanya Bay. The information extracted by the three-way models would be very useful
to regional agencies in developing a strategy to carry out scientific plans for resource use based on marine system functions. 相似文献
984.
The results of geotechnical explorations, engineering geological investigation (including laboratory and in situ tests) and
field observations have been used, along with borehole logging charts, to obtain the rock mass geotechnical data. Based on
the data, the rock mass along the Sabzkuh water conveyance tunnel route was classified by rock mass rating (RMR), Q-system
(Q), rock mass index (RMi) and geological strength index (GSI) (3 methods). A new series of correlations were established between
the systems based on the data collected from the study area. These relationships were then compared with those reported in
the literature, and two new relations were recommended. The classifications were utilized to calculate mechanical properties
(rock mass strength and deformation modulus) of the rock mass along the tunnel according to available empirical relations,
and to distinguish the upper-bound and lower-bound relations. 相似文献
985.
Twelve Recent benthic foraminiferal species hitherto not reported from the east and west coasts of India are presented and
illustrated. They are, namely- Bolivina semicostata, Elphidium subgranulosum, Hanzawaia nipponica, Planorbulina variabilis, Pseudononion japponicum, Reussella
haizumensis, Rosalina bradyi, Adelosina sp., Lagina sp. A, Lagina sp. B, Uvigerina sp. A and Uvigerina sp. B. 相似文献
986.
Medium- and Long-term Recovery of Estuarine and Coastal Ecosystems: Patterns,Rates and Restoration Effectiveness 总被引:1,自引:0,他引:1
Ángel Borja Daniel M. Dauer Michael Elliott Charles A. Simenstad 《Estuaries and Coasts》2010,33(6):1249-1260
Many estuarine and coastal marine ecosystems have increasingly experienced degradation caused by multiple stressors. Anthropogenic
pressures alter natural ecosystems and the ecosystems are not considered to have recovered unless secondary succession has
returned the ecosystem to the pre-existing condition or state. However, depending upon the scales of time, space and intensity
of anthropogenic disturbance, return along the historic trajectory of the ecosystem may: (1) follow natural restoration though
secondary succession; (2) be re-directed through ecological restoration, or (3) be unattainable. In order to address the gaps
in knowledge about restoration and recovery of estuarine and coastal ecosystems, this special feature includes the present
overview and other contributions to provide a synthesis of our knowledge about recovery patterns, rates and restoration effectiveness.
From the 51 examples collated in this contribution, we refine the recovery from the list of stressors into six recovery mechanisms:
(1) recovery from sediment modification, which includes all aspects of dredging and disposal; (2) recovery by complete removal
of stressors limiting natural ecosystem processes, which includes tidal marsh and inundation restoration; (3) recovery by
speed of organic degradation, which includes oil discharge, fish farm wastes, sewage disposal, and paper mill waste; (4) recovery
from persistent pollutants, which includes chemical discharges, such as TBT; (5) recovery from excessive biological removal,
related to fisheries and (6) recovery from hydrological and morphological modification. Drawing upon experience both from
these many examples and from an example of one comprehensive study, we show that although in some cases recovery can take
<5 years, especially for the short-lived and high-turnover biological components, full recovery of coastal marine and estuarine
ecosystems from over a century of degradation can take a minimum of 15–25 years for attainment of the original biotic composition
and diversity may lag far beyond that period. 相似文献
987.
aiNet- and GIS-based regional prediction system for the spatial and temporal probability of rainfall-triggered landslides 总被引:1,自引:0,他引:1
We developed a real-time forecasting system, aiNet-GISPSRIL, for evaluating the spatiotemporal probability of occurrence of
rainfall-triggered landslides. In this system, the aiNet (a kind of artificial neutral network based on a self-organizing
system) and GIS are merged for integrating the rainfall conditions into various environmental factors that influence the landslide
occurrence and for simulating the complex non-linear relationships between landslide occurrence and its related conditions.
Zhejiang Province (101,800 km2 in area), located in the southeast coastal region of China, is highly prone to the occurrence of landslides during intensive
rainfall. Since 2003, the aiNet-GISPSRIL has been used to predict landslides during the rainy seasons in the region. The aiNet-GISPSRIL
uses the regional 24-h forecast rainfall information and the real-time rainfall monitoring data from the rain-gauge network
as its inputs, and then provides 24-h forecast of the landslide probability for every 1 × 1-km grid cell within the region.
Verification studies on the performance of the aiNet-GISPSRIL show that the system has successfully predicted the dates and
localities of 304 landslides (accounting for 66.2% of reported landslides during the period). During the period from 2003
to 2007, because the system provided the probability levels of landslide occurrences up to 24-h in advance, gave locations
of potential landslides, and timely warned those individuals at high-risk areas, more than 1700 persons living in the risk
sites had been evacuated to safe ground before the landslides occurred and thus casualty was avoided. This highly computerized,
easy-operating system can be used as a prototype for developing forecasting systems in other regions that are prone to rainfall-triggered landslides. 相似文献
988.
The paper deals with the approximation and optimal interpolation of functions defined on the bisphere
\mathbb S2×\mathbb S2\mathbb {S}^{2}\times \mathbb {S}^{2} from scattered data. We demonstrate how the least square approximation to the function can be computed in a stable and efficient
manner. The analysis of this problem is based on Marcinkiewicz–Zygmund inequalities for scattered data which we present here
for the bisphere. The complementary problem of optimal interpolation is also solved by using well-localized kernels for our
setting. Finally, we discuss the application of the developed methods to problems of texture analysis in material science. 相似文献
989.
Ramakh Suleiman Shakhin 《Moscow University Geology Bulletin》2010,65(4):263-264
The study of hydrodynamic zonation and karst formation in the northwest part of Syria is a topical hydrogeological problem.
It is important to trace the history of karst formation and evaluate the spread of karst structures in the area and the rate
of development of karst processes, as well as their influence on water supplies and irrigation. The solution of this problem
was performed by integrated geophysical methods (electric and seismic exploration works) and data analysis of well-drilling,
geological, hydro-geological, and subsurface territory explorations. The most detailed works were done near Ras Al-Ain. This
paper is devoted to the results of the study of hydrodynamic conditions and karst formation. 相似文献
990.
Willapa Bay is a large, economically and ecologically important estuary on the Washington coast, USA for which the zooplankton
community has not previously been studied. Thus, in 2006 and 2007, six stations within Willapa Bay were sampled biweekly for
macrozooplankton, chlorophyll, and various abiotic variables to elucidate the processes underlying community composition and
dynamics. Non-metric multidimensional scaling identified water temperature and upwelling values as major factors defining
two distinct temporal communities. High densities and a community dominated by oceanic species (Calanus pacificus, Centropages abdominalis) marked the winter season, while summer (or the upwelling season) was dominated by estuarine species (Palaemonidae, Clevelandia ios). Smaller scale changes in the community were characterized by variation in chlorophyll a concentration and salinity and were marked by the presence of other taxa (Neotrypaea californiensis, Mysidae). These results point to the importance of physical processes, including the import of marine organisms and retention
of estuarine organisms, in the structuring of the macrozooplankton community in Willapa Bay. 相似文献