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A Field Investigation on the Effects of Background Erosion on the Free Span Development of a Submarine Pipeline

The safety of submarine pipelines is largely influenced by free spans and corrosions. Previous studies on free spans caused by seabed scours are mainly based on the stable environment, where the background seabed scour is in equilibrium and the soil is homogeneous. To study the effects of background erosion on the free span development of subsea pipelines, a submarine pipe- line located at the abandoned Yellow River subaqueous delta lobe was investigated with an integrated surveying system which in- eluded a Multibeam bathymetric system, a dual-frequency side-scan sonar, a high resolution sub-bottom profiler, and a Magnetic Flux Leakage （MFL） sensor. We found that seabed homogeneity has a great influence on the free span development of the pipeline. More specifically, for homogeneous background scours, the morphology of scour hole below the pipeline is quite similar to that without the background scour, whereas for inhomogeneous background scour, the nature of spanning is mainly dependent on the evolution of seabed morphology near the pipeline. Magnetic Flux Leakage （MFL） detection results also reveal the possible connec- tion between long free spans and accelerated corrosion of the pipeline.

Frequency and Absolute Number of FoxP3^+ Regulatory T Cells Correlate with Disease Progression of Chronic HIV-1 Infection

CD4^＋CD25^＋ Regulatory T cells （Treg） have been found to down-regulate immune activation in HIV-1 infection. However, whether the depletion of Treg benefits to the disease status of HIV infection remains undefined. To address this issue, we enumerated the Treg absolute counts and frequency in 75 antiviral-naive HIV-1-infected individuals in this study. It was found that HIV-infected patients displayed a significant decline in Treg absolute counts but a significant increase in Treg frequency. In addition, with disease progression indicated by CD4 T-cell absolute counts, circulating Treg frequency gradually increased; while Treg absolute counts were gradually decreased, suggesting that the alteration of Treg number closely correlated with disease progression in HIV infection Functional analysis further showed that Treg efficiently inhibit both CD4 and CD8 T cell proliferation in vitro. Thus, our findings indicates that Treg actively participate in pathogenesis of chronic HIV infection, influencing the disease progression.

Effect of Reclamation on Soil Environment in Sanjiang Plain

Soil environment in Sanjiang Plain has changed greatly because of the reclamation on a large scale.The physical and chemical properties of soil have changed, and soil erosion, soil saline-alkalization and soil pollution occurred in some areas. These problems have obstructed the sustainable development of agriculture. For the sustainable use of soils in Sanjiang Plain, in this paper we raise some suggestions and countermeasures which might be references for experts and departments concerned.

Farmers＇ Perception of Soil Erosion Control Measures： Implications for Sustainable Development in Agriculture and Environment in South East, Nigeria

The study investigated farmers＇ perception of soil erosion control measures and highlighted implications for sustainable development in agriculture and environment in southeast, Nigeria. Purposive, multistage and random sampling techniques were employed in selecting a sample size of two hundred and forty （240） respondents. Structured interview schedule was used for data collection, while percentages, mean ratings and factor analysis techniques were employed for analysis. The findings show that majority （64.6%） of farmers were within the ages of 40-59, while majority （67.9%） had either FSLC or WASCE/SSCE/GCE/OL qualifications. The farmers reported that the major soil erosion control measures used were strip cropping （M = 4.8） and making of ridges against slopes （M = 4.7）. The study reported that poor group affinity, inadequate institutional support and inadequate technical knowhow were constraints to soil erosion control in southeast, Nigeria. The study highlighted implications for sustainable development in agriculture and environment on organizational overhaul in extension, participatory extension policy on farmers groups and institutional re-orientation and synergy between Universities, Agricultural Development Programme （ADP）, Ministry of Agriculture （MOA） and Local Government Councils. In conclusion, success in soil erosion control and sustainable development in agriculture and environment in southeast, Nigeria depends on the extent issues raised and implications highlighted can be addressed. The study recommends improved funding support to extension, participatory extension training and contacts with farmers＇ groups and groups＇ resources management.

Assessment of Saline Water Intrusion into Huong River in Dry Season

Most rivers in Vietnam flow directly to the sea where the interaction between fresh and salt water occurs. Because of uneven flow distribution through the year with only 20% annual flow in the dry season, while fresh water requirement for socio-economic activity in this season is much higher. With this situation, the simulation and finding out the mechanism of saline water intrusion into the estuary in general will help to suggest suitable solutions to control the situation. This paper presents results done at the Huong river estuary. Based on the data collected in current years and using MIKE11 softwave, number scenarios were simulated and found out the intruded process of saline water into the river. They will be very important parameters for which solutions to control negative effects to serve socio-economic development at the downstream of Huong river will be recommended and implemented in the later stage.

The Impact of Deforestation in Anambra State： The Ekwusigo Example

It is a fact that demographic and socio-economic developments are exploitatively exerting severe pressure on forest resources in Nigeria. Not only has the economy of the people been severely affected but also the environment has witnessed accelerated soil erosion, especially in Eastern Nigeria. Accordingly, this study set out to explore the environmental and socio-economic impacts of deforestation using an empirical case. Two forested and two deforested sites in Ekwusigo L.G.A of Anambra State were closely studied with respect to deforestation indices. From the data generated, Student＇s t-test was used to attempt a statistical comparison of the forested and deforested sites. The findings indicate that forest cover depletion affected both the canopy openness and the number of non-timber forest products in the area, Finally, the paper stressed the need to maintain a sustainable plant cover while economically harnessing forest resources.

Cogitation on developing a dynamic model of soil wind erosion

Studies on soil wind erosion began with single factors affecting soil wind erosion; with increasing quantities of data being accumulated,the wind erosion equation(WEQ),the revised wind erosion equation(RWEQ),the wind erosion prediction system(WEPS),and other soil wind erosion models have been successively established,and great advances have been achieved.Here we briefly review the soil wind erosion research course and analyze the advantages and disadvantages of the current soil wind erosion models.From the perspective of the dynamics of wind erosion,we classified the factors affecting soil wind erosion into three categories,namely,wind erosivity factors(WEF),soil antierodibility factors(SAF),and roughness interference factors(RIF).We proposed the concept of a standard plot of soil wind erosion to solve the problem of uncertainty of the soil wind erosion modulus on a spatial scale,and provided methods to set similarity conditions in wind tunnel simulation experiments and to convert the spatial scale of the wind erosion modulus from the standard plot to a large scale field.We also proposed a conceptual model on the basis of the dynamics of soil wind erosion with the theoretical basis that wind produces a shear force on the soil surface.This shear force is partitioned by barely erodible soil surfaces and roughness elements on the ground,and the amount of soil loss by wind should be calculated by comparing the shear force of the wind on barely erodible soil surfaces with the anti-erosion force of the surface soil.One advantage of this conceptual model is that the calculated soil wind erosion modulus is not subject to changes of spatial scale.Finally,we recommended continual improvement of the existing models while also establishing new models.