The temporal change of driving factors during the course of land desertification in arid region of North China: the case of Minqin County

Taking the key research area in the arid region of North China—Minqin County—as a case, this paper analyzes the main factors impacting land desertification. Based on factor analysis method and the collection of data in the last 50 years, this paper researches the spatial changes of driving factors during the course of land desertification in Minqin, Gansu Province. The results of factor analysis indicate that the driving force of human factor on land desertification accounted for 56.33% in 1956–2004 and for 66.19% in 1981–2004, the driving force of nature factor on land desertification accounted for 11.29% in 1956–2004 and 8.11% in 1981–2004, and the synthesis of driving forces of human and natural factors accounted for 11.19% in 1956–2004 and for 14.88% in 1981–2004. This indicated that human driving force on land desertification was increasing in Minqin County gradually.     

Women and the access to knowledge and new technologies: The case of Pisa

Emphasis has been given to a number of aspects which characterise technological development in today's economic systems and which have an impact on the working environment and on gender differences. Technological change is leading to a strong divide between knowledge “producers” and “users”. The possibility of access to one or both knowledge systems indicates the extent of women's participation in the economic and spatial transformations brought about by the new technologies. This research aims to analyse the development of new technologies and the presence of the female workforce in the field of new knowledge generation, and also to verify gender-related conditions in learning and using new technologies. In particular, an analysis has been carried out of the empirical case study of Pisa, a point of reference for comparisons with other Italian and European cases. The research focuses on: the examination of women's capabilities in the field of new technologies through the analysis of University training courses; the analysis of women's presence and status among the university staff, especially in science and technology; a detailed survey of female employment in innovative sectors. The results of the research emphasise the gender perspectives of inclusion — as regards the application of technologies — and exclusion — as regards the generation of knowledge — of women in or from new technologies. At the same time, the research stresses the growth of women's roles in this sector during recent years and, by reconstructing life histories, underlines the conditions and difficulties that have been met by women entering these new types of employment. This revised version was published online in July 2006 with corrections to the Cover Date.     

A hypoplastic macroelement model for shallow foundations under monotonic and cyclic loads

In this work, a macroelement for shallow foundations on sands has been developed based on the theory of hypoplasticity. The incrementally nonlinear constitutive equations of the macromodel are defined in terms of generalized forces and displacements and are constructed based on the general approach proposed by Niemunis (Extended Hypoplastic Models for Soils. Habilitation Thesis, Bochum University, 2002). A suitable vectorial internal variable—mimicking the concept of intergranular strain introduced by Niemunis and Herle (Mech Cohes Frict Mater 2:279–299, 1997) for continuum hypoplasticity—is employed to provide the model sufficient memory of past displacement history to be able to reproduce the observed behavior under cyclic loading paths. As compared to similar macroelements formulated within the framework of the theory of elastoplasticity, the proposed approach has the advantage of a much simpler mathematical structure, which allows a straightforward implementation in existing structural analysis FE codes. The model performance has then been evaluated by comparing the model predictions with available experimental results from a series of small-scale model tests reported by Nova and Montrasio (Géotechnique 41:243–256, 1991). Overall, the model captures reasonably well the observed response under nonproportional, complex loading paths. A series of simulations reproducing the tests performed by di Prisco et al. (Shallow footing under cyclic loading: experimental behaviour and constitutive modelling. Patron, Bologna, 2003) has also demonstrated the potential of the proposed model to simulate the observed behavior of footings under cyclic loading paths, at least from a qualitative point of view.     

The regional distribution regularity of landslides and their effects on the environments in the Three Gorges Reservoir Region, China

On the basis of research and analysis of the landslide system of the Three Gorges Reservoir area, this paper systematically analyzes and studies the temporal–spatial distribution law of landslides of this reservoir area and their impacts on environment of this area. The paper puts forward that the temporal–spatial distribution of this area’s landslides is mainly controlled by lithologic characters of strata, geological structure, valley landscape, and types of bank slope structure; landslide deformation and failure have such characteristics as simultaneity, laggardness, cyclical instability, and stage. Besides, the paper systematically analyzes and studies the main impacts of landslide on environment and points out that landslides and collapses will bring about relatively serious impacts on relocation and layout of cities and towns along the banks. These impacts mainly include the increase of relocation investment, number of migrants, and compensation for losses. Much attention and evaluation should be paid to the impacts of Xintan Landslide and Lianziya Landslide—large landslides near the Dam—on the construction and safety of the Three Gorges Project. However, landslides have relatively small impacts on shipping and reservoir capacity. The above-mentioned research is of great guiding significance for the construction of the Three Georges Project, planning and construction of cities and towns along the banks, and protection of geological environment.     

Indian monsoon variability in relation to Regional Pressure Index

In this paper Regional Pressure Index (RPI) over the Indian region (20‡N—40‡N and 70‡0E—85‡E) has been constructed for 101 years (1899-1999) on a monthly scale. The relationship of these indices was carried out with the Indian Summer Monsoon Rainfall (June–September) (ISMR) over the various homogeneous regions, for all the time scales. From the analysis it has been seen that RPI in the month of May is significantly associated with ISMR over various regions on all the scales. The relationship is statistically significant at 1% level. The study reveals that RPI in the month of May and January will be a new precursor for the long range forecasting of ISMR on the smaller spatial scale. On the decadal and climatological scale, winter and spring time RPI show a significant inverse relationship with the rainfall over the regions Peninsular India (PI) and North West India (NWI), while the association is direct with Central North East India (CNEI) and North East India (NEI). The relationship is significant at 0.1 and 1% level respectively.     

Slip rate variations on faults in the Basin-and-Range Province caused by regression of Late Pleistocene Lake Bonneville and Lake Lahontan

Late Pleistocene regression of two large pluvial lakes—Lake Bonneville and Lake Lahontan—caused considerable lithospheric rebound in the Basin-and-Range Province, USA. Here, we use finite-element models to show how lake growth and regression affect the temporal and spatial slip evolution on faults near the former lakes. Our results show that fluctuations in the volume of Lake Bonneville caused along-strike slip variations on the Wasatch normal fault, with a pronounced slip rate increase on its northern and central parts during lake regression. The response of normal and strike-slip faults near the ring-shaped Lake Lahontan depends on their location within the rebound area. Faults located in the centre of rebound show a slip rate increase during lake regression, whereas strike-slip faults at the periphery decelerate. All slip rate variations are caused by differential stress changes owing to changing lake levels, regardless of the individual fault response.     

Three-phase numerical model of water migration in partially frozen geological media: model formulation,validation, and applications

Water in the subsurface of the Earth’s cold regions—and possibly the subsurface of Mars—resides in the liquid, vapor, and ice phases. However, relatively few simulations addressing full three-phase, nonisothermal water dynamics in below-freezing porous media have been undertaken. This paper presents a nonisothermal, three-phase approach to modeling water migration in partially frozen porous media. Conservation equations for water (as ice, liquid, and vapor) and a single gas species (in the gas phase and dissolved in water) are coupled to a heat transport equation and solved by a finite-volume method with fully implicit time stepping. Particular attention is given to the method of spatial differencing when the pore space is partially filled with ice. The numerical model is able to reproduce freezing-induced water redistribution observed in laboratory experiments. Simulations of Earth permafrost dynamics and of the formation and evolution of a planetary-scale cryosphere on Mars demonstrate the new capabilities.     

Modelling the responses of mature forest trees to air pollution

Systems analysis of the responses of forest trees to air pollutants led to mathematical models which represent the essential life processes of mature trees (photosynthesis, respiration, growth etc.) under ‘normal’ conditions and — especially — under pollution strees. Computer simulations using these models have made it possible to test and analyse the consequences of — known or hypothetical — pollution effects. The simulation runs have led to the identification of three distinct behavioural modes (growth, stagnation, breakdown) and corresponding stable and unstable system states. The results have produced new insights and contributed to the understanding of the dieback process of spruce and beech trees. The presentation will concentrate on the most recent and most complex of the hitherto existing models, theBeech model.     

Depositional characteristics of Dalong Formation and its potential as hydrocarbon source rocks in Hubei,Hunan ,Guizhou and Guangxi

The Late Permian Dalong Formation in Hubei, Hunan, Guizhou and Guangxi in South China could be subdivided into several sedimentary types according to the lithology, indicative of the great spatial variations of both the lithology and sedimentary facies. The Dalong Formation deposited during the highest transgression of Late Permian, in particular under the anaerobic and suboxic conditions, which shows a strong linkage with the hydrocarbon source rocks. The Dalong Formation has some favorable properties such as hydrocarbon source rocks, including the sediments deposited in highest transgression sea level, the deep slope sedimentary environments and the low sedimentary rate, which raises the importance of the investigations on the sedimentary features, the geochemical properties and their relationship with the oil potential. __________ Translated from Earth Science—Journal of China University of Geosciences, 2007, 32(6): 774–780 [译自: 地球科学—中国地质大学学报]     

Formation and characteristics of post-earthquake debris flow: a case study from Wenjia gully in Mianzhu, Sichuan, SW China

During the three flood seasons following the Wenchuan earthquake in 2008, two catastrophic groups of debris flow events occurred in the earthquake-affected area: the 2008-9-24 debris flow events, which had a serious impact on rebuilding; and the 2010-8-13/14 debris flow events, which destroyed much of the progress made in rebuilding. The Wenjia gully is a typical post-earthquake debris flow gully and at least five debris flows have occurred there. As far as the 2010-8-13 debris flow is concerned, the deposits of the Wenjia gully debris flow reached a volume of 3.1 × 10⁶ m³ in volume and hundreds of newly built houses were buried. This study took the Wenjia gully debris flow as an example and discussed the formation and characteristics of post-earthquake debris flow on the basis of field investigations and a remote sensing interpretation. The conclusions drawn from the investigation and analysis were as follows: (1) Post-earthquake debris flows were a joint result of both the earthquake and heavy rainfall. (2) Gully incision and loose material provision are key processes in the initiation and occurrence of debris flows and a cycle can be presented as the following process: runoff—erosion—collapse—engulfment—debris flow—further erosion—further collapse—further engulfment—debris flow enlargement. (3) The amount of rainfall that triggered debris flows from the Wenjia gully was significantly less than the average daily rainfall, while the intraday rainfall threshold decreased by at least 23.3%. (4) The occurrence mechanism of Wenjia gully debris flow was an erosion type and there was a positive relationship between debris flow magnitude and rainfall, which fitted an exponential model. (5) There were five representative characteristics of Wenjia gully debris flow: the long duration of the occurring process; the long distance of deposition chain conversion during the process of damage; magnification in the scale of debris flow; and the high frequency of debris flow events.     

Inter-metropolitan migration of the newly landed immigrants in Canada: 1991–1996 and 1996–2001

Based on the tabulations of the Longitudinal Immigration Data Base, I characterized, explained and compared the 1991–1996 and 1996–2001 inter-metropolitan migration of the newly landed immigrants in Canada. The spatial and temporal patterns were consistent with the neoclassical economic theory and the ethnic enclave theory. In making their decisions on departure and destination choices, the immigrants were responsive to income and employment incentives, as well as the retaining and attracting powers of ethnic communities among Census Metropolitan Areas (CMAs). The research also discovered an interesting temporal pattern—while the inter-CMA migration of immigrants accentuated the over representation of the immigrants in Toronto and Vancouver in the 1991–1996 period, the rise of the “secondary” CMAs led to a spatial dispersal of the immigrants in the 1996–2001 period. This finding supplements the existing literature on internal migration of Canadian immigrants, which discovered little evidence of an increased dispersion of immigrants over time.     

The Effect of Consolidation on TBM Shield Loading in Water-Bearing Squeezing Ground

When planning a TBM drive in squeezing ground, the tunnelling engineer faces a complex problem involving a number of conflicting factors. In this respect, numerical analyses represent a helpful decision aid as they provide a quantitative assessment of the effects of key parameters. The present paper investigates the interaction between the shield, ground and tunnel support by means of computational analysis. Emphasis is placed on the boundary condition, which is applied to model the interface between the ground and the shield or tunnel support. The paper also discusses two cases, which illustrate different methodical approaches applied to the assessment of a TBM drive in squeezing ground. The first case history—the Uluabat Tunnel (Turkey)—mainly involves the investigation of TBM design measures aimed at reducing the risk of shield jamming. The second case history—the Faido Section of the Gotthard Base Tunnel (Switzerland)—deals with different types of tunnel support installed behind a gripper TBM.     

Bauxite provinces of the world

Phanerozoic bauxite provinces are contoured and characterized. The relations to large tectonic units—ancient and young platforms, island arcs and foldbelts, active continental margins, etc.—are chosen as the major criterion for the recognition of bauxite provinces; 19 provinces of different age and conditions of bauxite deposition are described. Single- and multistage as well as single- and multilevel provinces are distinguished depending on the type of tectonic and geomorphic structure. The most productive bauxite provinces are located in the present-day tropical zone within ancient Gondwanan platforms. Three-level provinces with Cretaceous bauxite at the highest and oldest (post-Gondwanan) surface and Cenozoic deposits at lower and younger planation surfaces are predominant. The most complex, two- and three-stage and multilevel provinces are related to ancient fold regions. The single-level provinces are localized in young island arcs and oceanic islands. The prevalent genetic types of bauxite deposits—lateritic, sedimentary, and karst—are shown in the map of bauxite provinces.     

Factors of poultry farming adoption in Oyo State,Nigeria: A study in agency- and infrastructure-based diffusion

In this paper, use is made of the multiple regression technique in an attempt to provide explanation for the pattern of adoption of intensive poultry farming technique — an agency and infrastructure based innovation. This paper deals with two aspects of the diffusion. The first examines the factors of spatial pattern of adoption and the second, the adoption intensity. The paper then turns to consider the planning implications of these factors. In Oyo State, market factor expressed as the population size of towns, distance to agency location and from previous adopters largely account for the spatial variation in the time of adoption of ‘modern’ poultry farming technique. The intensity of adoption (poultry population) on the other hand is influenced by the number of adopters, distance to infrastructure, profitability considerations, literacy factor and the time of adoption.     

Application of Glauconite Sedimentary Geochronology

Glauconite is widely distributed in space and time.In China glauconite-bearing strata are extensive occurrence ranging from Late Cretaceous to Middle Proterozoic in age.X-ray powder analysis,X-ray diffracition analysis and differential thermal analysis revealed that glauconite has a mica-type structure between dioctahedron and trioctahedron.Its chemical composition is:Al2O310.6%,SiO249.23%,MgO3.24%,Fe2O317.40%,FeO1.8%,and K2O7.92%,Its crystal form and thermal properties are very similar to those of mica-like clay minerls.According to isotopic age determinations of glauconite in modern oceans (including the East China Sea,the South China Sea and the Yellow Sea),we consider that in the extreme case glauconite is an authigenic mineral.It is generally formed in sedimentary rocks.Is has further proved that glauconite can be used to determine the ages of sedimentary rocks.     

Erratum: Geochronology of Late Cenozoic volcanism in the area of Lake Van,Turkey: An example of developmental dynamics for magmatic processes [Doklady earth sciences, 433(2), pp. 1031–1037]

An isotope-geochronological study has been performed to examine the products of Late Cenozoic collision volcanism on the northern coast of Lake Van, Turkey. We obtained 45 new K—Ar dates, based on which the principal time characteristics of volcanic activity in the region have been determined. Volcanic activity in the northern coast of Lake Van has lasted ∼15 myr; it has had an expressed discrete nature, when periods of intense volcanic activity alternated with long-lasting pose periods. Four stages of Neogene—Quaternary volcanism have been identified: Middle Miocene (15.0—13.5 Ma), Late Miocene (10—9 Ma), Pliocene (5.8—3.7 Ma), and Quaternary (1.0—0.4 Ma). The average duration of the stages was 1—2 myr; the stages were separated from each other with periods of inactivity of approximately equal lengths (∼3 myr). For each of the Pliocene and Quaternary stages, three additional phases of volcanism have been identified, which were separated from each other with short time intervals (a few hundred thousand years). The last burst of volcanic activity in the study area occurred ∼400 ka; similar to Quaternary volcanism in general, it was not characterized by a high intensity. An important result of the studies performed was to confirm the existence of a separate Middle Miocene stage of collision volcanism for the Caucasian—Anatolian Segment of the Alpine Fold Belt. New geochronological data generated presented in this paper indicate that Neogene—Quaternary volcanism in this portion of the belt started much earlier (∼15 Ma) than assumed by the majority of the previous researchers.     

Promoting local management in groundwater

There is a strong case for making greater effort to promote local groundwater management—in addition to other measures that regulate groundwater use. Though scattered, there are several examples—from India, Pakistan, Yemen and Egypt—where groundwater users effectively self-imposed restrictions on the use of groundwater. There are a number of recurrent themes in such spontaneously-developed examples of local regulation: the importance of not excluding potential users; the importance of simple, low transaction cost rules; the power of correct and accessible hydrogeological information; the possibility of making more use of demand and supply management strategies; and the important supportive role of local governments. The case is made, using examples, for actively promoting local groundwater management as an important element in balancing groundwater uses. Two programmes for promoting local groundwater management in South India are described—one focussing on participatory hydrological monitoring, and one focussing on micro-resource planning and training. In both cases the response was very positive and the conclusion is that promoting local groundwater regulation is not difficult, costly or sensitive and can reach the necessary scale quickly.     

Map of the 6.7 GHz class II methanol maser emission of the protoplanetary disk G23.01-0.41

We present images of the star-forming regionG23.01–0.41 at 6.7GHz in the Class II methanol maser transition 5₁–6₀ A ⁺, produced from archival observations on the European VLBI Network. Our map of the source and its maser spots contains 24 maser components. The data for each spot—absolute coordinates, coordinates relative to the calibration feature, peak flux and flux integrated over the spot, size, position angle, velocity along the line of sight, and line full width at half-maximum—are collected in tabular form. The spatial region occupied by the maser spots is approximated by a 200×130 milliarcsec ellipse in position angle PA = −0.40°, centered on the absolute coordinates α ₀ = 18^h34^m40.282^s, δ ₀ = −09°00′38.27″ (J2000). If the source is a protoplanetary disk, then, for the distance estimate derived from trigonometric parallax, its diameter is 1800 AU, and the mass of the central protostar is 23.5M _⊙.     

Diatoms from surface sediments of Enderby Basin of Indian Sector of Southern Ocean

Diatoms from surface sediment samples collected from Enderby Basin of Indian Sector of Southern Ocean were analyzed to determine the relative abundance and distribution of seven key indicator diatom species viz. Sea ice related species Fragilariopsis rhombica, F. separanda, F. curta, F. ritscheri, Thalassiosira tumida and Actinocyclus actinochilus and Open Ocean species F. kerguelensis on the basis of modern physico-chemical parameters. The relative abundances of different species observed viz. F. rhombica — 6.25%; F. separanda — 12.5%; F. curta — 10.53–13.33%; F. ritscheri — 4.55–12.5%; F. kerguelensis — 6.25–63.64%; T. tumida — 3.13% and A. actinochilus — 9.38–13.33%. The increasing abundance of F. kerguelensis consecutively suggests the effect of Antarctic bottom water in the study area which is further substantiated by the presence and increasing abundance of F. ritscheri. The gradual decrease in abundance or absence of sea ice related species from the sampled stations indicates the summer and winter sea ice extent concentration in the study area. The nutrient concentration correlates with the distribution and abundances of diatom species.     

Green Crab Larval Retention in Willapa Bay,Washington: An Intensive Lagrangian Modeling Approach

The European green crab (Carcinus maenas) is invasive on the U.S. West Coast. This study uses a high-resolution circulation model to determine the likelihood that green crab larvae spawned in Willapa Bay, Washington could be retained by circulation and behavior long enough to reach maturity and resettle within the bay. A particle-tracking method (the “diffusive Lagrangian return map”) is presented that makes it possible to track the dispersion of hundreds of thousands of model larvae—each subject to three-dimensional advection, vertical turbulent diffusion, and imposed vertical migration behavior—over their full 30–50 days development time with modest computational resources. Larvae spawned in summer show significant retention (5–40%) in the southern and western portions of the bay, including the Stackpole shoals near the mouth, the area most likely to be colonized by late-stage megalopae arriving from the coastal ocean. Larvae spawned in spring show much less retention throughout the bay because of (1) increased flushing caused by increased river input relative to summer conditions and (2) longer development times caused by lower water temperatures. The role of larval swimming behavior is secondary to hydrodynamics in setting these spatial and seasonal patterns of retention.