Role of Wind-Sand Disturbance in the Formation and Development of Tamarix taklamakanensis Community

Formation, development and degeneration of Tamarix taklamakanensis M.T. Liu community may be affected by wind-sand disturbance. On the basis of field survey and experiments that took eight years from 1994, it was found that the plant community was formed in wet and low-lying land, developed in sand burying land, and died out in the land with strong wind erosion and severe sand burying. In the initial stage of the community formation, the low-lying land that was formed by wind erosion provided a suitable habitat for seed germination and plant rooting, but salt stress from ground water reduced seedling survival rate. In the developing stage of the community, sand burying stimulated vigorous growth of the shrubs. In the degenerative stage of the community, the wind erosion and sand burying resulted in dying out of the shrubs. It is therefore concluded that wind-sand disturbance has a positive role in the formation and development of the community, and is in a close association with the process of the community degeneration. Taking the habitat of T taklamakanensis into account, it may be appropriate to note that, under the conditions of frequent disturbance and severe stress, desert pioneer species are adaptable and able to survive. This might be a supplement to the CSR strategy.

Bone morphogenetic protein-2 gene controls tooth root development in coordination with formation of the periodontium

Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey＇s fibers of the periodontal ligament （PDL）. However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 （Bmp2） in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 （PO）, followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2gene is removed from Sp7＋ （Osterix＋） cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC （Nfic）, periostin and α-SMA＋ cells. Third, there is a failure to produce vascular endothelial growth factor A （VEGF-A） in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKOsp7-cre＇EGFe. Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKOsp7-cre＇EGFe. These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation.

Development features of volcanic rocks of the Yingcheng Formation and their relationship with fault structure in the Xujiaweizi Fault Depression,Songliao Basin,China

The Xujiaweizi Fault Depression is located in the northern Songliao Basin,Northeast China.The exploration results show that the most favorable natural gas reservoirs are in the volcanic rocks of the Yingcheng Formation（K 1 yc）.Based on seismic interpretation,drill cores and the results of previous research,we analyzed the distribution of faults and the thickness of volcanic rocks in different periods of K 1 yc,and studied the relationship of volcanic activities and main faults.Volcanic rocks were formed in the Yingcheng period when the magma erupted along pre-existing fault zones.The volcanic activities strongly eroded the faults during the eruption process,which resulted in the structural traces in the seismic section being diffuse and unclear.The tectonic activities weakened in the study area in the depression stage.The analysis of seismic interpretation,thin section microscopy and drill cores revealed that a large number of fractures generated in the volcanic rocks were affected by later continued weak tectonic activities,which greatly improved the physical properties of volcanic reservoirs,and made the volcanic rocks of K 1 yc be favorable natural gas reservoirs.The above conclusions provide the basis to better understand the relationship of the volcanic rock distribution and faults,the mechanism of volcanic eruption and the formation of natural gas reservoirs in volcanic rocks.

TGF-β and BMP signaling in osteoblast,skeletal development,and bone formation,homeostasis and disease

INTRODUCTIONThe transforming growth factor-β （TGF-β） superfamily com- prises TGF-βs, Activin, bone morphogenetic proteins （BMPs） and other related proteins. TGF-β superfamily members act through a heteromeric receptor complex,, comprised of type I and type II receptors at the cell surface that transduce intracellular signals via Smad complex or mitogen-activated protein kinase （MAPK） cascade.

Ground fissure development regularity and formation mechanism of shallow buried coal seam mining with Karst landform in Jiaozi coal mine: a case study

A comprehensive study was undertaken at Jiaozi coal mine to investigate the development regularity of ground fissures in shallow buried coal seam mining with Karst landform,shedding light on the development type,geographical distribution,dynamic development process,and failure mechanism of these ground fissures by employing field monitoring,numerical simulation,and theoretical analysis.The findings demonstrate that ground fissure development has an obvious feature of subregion,and its geographical distribution is significantly affected by topography.Tensile type,open type,and stepped type are three different categories of ground fissure.Ground fissures emerge dynamically as the panel advances,and they typically develop with a distance of less than periodic weighting step distance in advance of panel advancing position.Ground fissures present the dynamic development feature,temporary fissure has the ability of self-healing.The dynamic development process of ground fissure with closed-distance coal seam repeated mining is expounded,and the development scale is a dynamic development stage of“closure→expansion→stabilized”on the basis of the original development scale.From the perspective of topsoil deformation,the computation model considering two points movement vectors towards two directions of the gob and the ground surface is established,the development criterion considering the critical deformation value of topsoil is obtained.The mechanical model of hinged structure of inclined body is proposed to clarify the ground fissure development,and the interaction between slope activity and ground fissure development is expounded.These research results fulfill the gap of ground fissures about development regularity and formation mechanism,and can contribute to ground fissure prevention and treatment with Karst landform.

Experimental Study on Heartwood Formation and Development of Red Sandalwood by Grafting

Red sandalwood(Pterocarpus santalinus)is the most precious species of Pterocarpus,and the long maturity period of its heartwood is an important factor limiting its development.The 1-year-old plants of P.macarocarpus were chosen as the rootstocks to graft red sandalwood with single-bud scions of 1-year-old shoots in spring.The 5-month survival rate reached over 80%,and the grafted plants grew well.Moreover,the grafting significantly promoted the formation and development of the heartwood of red sandlawood.At 18^(th)month after grafting,compared with the seedling plants,the diameter of heartwood was increased by 82.8%and 29.6%,respectively,and the ratio of heartwood increased by 64.8%and 29.6%,respectively.The propagation technology had outstanding practical value and scientific significance,which has not been reported at home and abroad.

GEOLOGICAL FORMATIONS AND GEOTECTONIC DEVELOPMENT OF SARAWAK AND SABAH, EAST MALAYSIA

Sarawak and Sabah forms part of the continental margin extending belt of Southeast Asia.Based on the discussion of sedimentary, magmatic and metamorphic formations resulting from geotectonic development from the Paleozoic to the Cenozoic. this area may be subdivided into two different tectonic regions. Geotectonic development and evolution of the regional crust are subsequently discussed in the paper.

Characteristics and development model of karst reservoirs in the fourth member of Sinian Dengying Formation in central Sichuan Basin,SW China

The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,logging and seismic data.A development model of karst reservoirs is constructed to support the high-efficiency development of gas pools.The research shows that the reservoirs in Deng 4 Member have mainly small-scale karst vugs and fractures as storage space,and can be divided into three types,fracture-vug,pore-vug and pore types.The development patterns of the karst reservoirs are determined.On the plane,the karst layers increase from 65 m to 170 m in thickness from the karst platform to the karst slope,and the high-quality reservoirs increase from 25.0 m to 42.2 m in thickness;vertically,the reservoirs at the top of Deng 4 Member appear in multiple layers,and show along-bedding and along fracture dissolution characteristics.The reservoirs at the bottom are characterized by the dissolution parallel to the water level during the karstification period,and have 3-5 large-scale fracture-cave systems.Based on the reservoir development characteristics and the genetic mechanism,three types of reservoir development models of karst reservoir are established,i.e.,bed-dissolved body,fracture-dissolved body and paleohorizon-dissolved body.The construction of karst reservoir development models and seismic response characteristics of the three types of reservoirs can provide parameter for well placement and trajectory design,and substantially improve productivity and development indices of individual wells and gas reservoirs.The designed production capacity of the gas reservoir has enhanced from the initial 3.6 billion to 6 billion cubic meters,making the profit of the reservoir development increase noticeably.

THE MAIN METEOROLOGICAL FACTORS OF FORMATION AND DEVELOPMENT OF MIRE MEADOW OF QINGHAI LAKE DRAINAGE AREA

Qinghai Lake is located in the northeastern Qinghai Xizang(Tibet) Plateau. It is an especially big light saltwater lake. The mire meadow in Qinghai Lake drainage area is an eco system which is affected by the eco environment factors. Its formation, development and temporal and spatial distribution law are decided by a few main meteorological factors in the eco environment to a certain extent. The main meteorological factors are ≥10℃ accumulated temperature, precipitation from May to September and annual humidity coefficient. The mathematical model of the mire wetland rate and the main meteorological factors is given by multivariate linear regression in the paper.

Study on the Role of Tidal Currents in the Process of Formation and Development of the Changjiang River Delta

The Changjiang River Delta is a delta of tremendous scale which is formed under the control of tide and tidal currents. The study on the role of tide and tidal currents in the process of formation and development of the Changjiang River Delta can provide a typical example for the ocean-continent interaction process in the east area of our country. The tide and tidal currents in the Bohai Sea, Yellow Sea and East China Sea at the post-glacial transgression maximum are simulated, the sediment transport field in the Paleo-Changjiang River Estuary(PCRE) and its peripheral area at that time is calculated, and the seabed erosion/accretion pattern is obtained according to the divergence of sediment transport rate. The results show that a distinctive wave belly of standing tidal wave existed at the post-glacial transgression maximum and the wave belly lines protruded seawards from the wave belly point in the mouth of the PCRE. Under the wave belly control tidal currents converge to or diverge from the wave

Extensional Tectonics, Rifting, Formation of Sedimentary Basins, Cretaceous Volcanism, Emplacement of Dyke Swarms and Development of Hydrocarbon Pools: Case Studies from Peninsular India and Indian Ocean Region

Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression

Transcriptional,post-transcriptional and post-translational regulations of gene expression during leaf polarity formation

Leaf morphogenesis requires the establishment of adaxlal-abaxlal polarity after primordium initiation from the snoot apical meristem （SAM）. Several families of transcription factors are known to play critical roles in promoting adaxial or abaxial leaf fate. Recently, post-transcriptional gene silencing pathways have been shown to regulate the establishment of leaf polarity, providing novel and exciting insights into leaf development. For example, microRNAs （miR 165/166） and a trans-acting siRNA （TAS3-derived tasiR-ARF） have been shown to repress the expression of several key transcription factor genes. In addition, yet another level of regulation, post-translational regulation, has been revealed recently by studies on the role of the 26S proteasome in leaf polarity. Although our understanding regarding the molecular mecha- nisms underlying establishment of adaxial-abaxial polarity has greatly improved, there is still much that remains elusive. This review aims to discuss recent progress, as well as the remaining questions, regarding the molecular mechanisms underlying leaf polarity formation.

China's shale gas exploration and development: Understanding and practice

Through detailed analyses of the distribution characteristics of organic-rich shale, appearance features of high-quality shale, microscopic characteristics of shale reservoir rocks, fracability, and the relationship between preservation conditions and shale gas enrichment in Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Sichuan Basin, theoretical understandings and specific suggestions with respect to the exploration and development of shale gas in China are summarized and proposed respectively. Important geological understandings in the exploration and development of shale gas of the Wufeng Formation–Longmaxi Formation in the Sichuan Basin can be summarized into the following aspects: depositional environment and depositional process control the distribution of organic-rich shale; high quality shale in "sweet spot segments" are commonly characterized by high content of organic carbon, high brittleness, high porosity and gas content; organic pores are important storage space for the enrichment of shale gas; preservation conditions are the key factor for the geological evaluation of shale gas in structurally complex regions; shale gas can be considered as "artificial gas reservoirs" and the fracability assessment is essential for high-production; nanoscale storage space and the mode of occurrence control the special seepage characteristics of shale gas. The following suggestions are proposed for the development of China's shale gas industry:(1) focus more on fundamental research to achieve new breakthrough in the geological theory of shale gas;(2) emphasize exploration practices to have all-round discoveries in multiple strata;(3) study the regularities of development and production to establish new models of shale gas development;(4) think creatively to invent new technologies to tackle key problems;(5) explore the management innovation to create new mechanisms in shale gas development.

Rehabilitation of bauxite residue to support soil development and grassland establishment

Rehabilitation(amendment and vegetation establishment)on bauxite residue is viewed as a promising strategy to stabilize the surface and initiate soil development.However,such approaches are inhibited by high pH,high exchangeable sodium(ESP)and poor nutrient status.Amendment with gypsum is effective in improving residue physical and chemical properties and promoting seed establishment and growth.Application of organics(e.g.compost)can address nutrient deficiencies but supplemental fertilizer additions may be required.A series of germination bioassays were performed on residue to determine candidate species and optimum rehabilitation application rates.Subsequent field trials assessed establishment of grassland species Holcus lanatus and Trifolium pratense as well as physical and chemical properties of amended residue.Follow up monitoring over five years assessed elemental content in grassland and species dynamics.With co-application of the amendments several grassland species can grow on the residue.Over time other plant species can invade the restored area and fast growing nutrient demanding grasses are replaced.Scrub species can establish within a 5 Yr period and there is evidence of nutrient cycling.High pH,sodicity and nutrient deficiencies are the major limiting factors to establishing grassland on residue.Following restoration several plant species can grow on amended residue.

Distribution characteristics, exploration and development, geological theories research progress and exploration directions of shale gas in China

The shale gas resources in China have great potential and the geological resources of shale gas is over 100×10^(12)m^(3),which includes about 20×10^(12)m^(3) of recoverable resources.Organic-rich shales can be divided into three types according to their sedimentary environments,namely marine,marine-continental transitional,and continental shales,which are distributed in 13 stratigraphic systems from the Mesoproterozoic to the Cenozoic.The Sichuan Basin and its surrounding areas have the highest geological resources of shale gas,and the commercial development of shale gas has been achieved in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in these areas,with a shale gas production of up to 20×10^(9)m^(3) in 2020.China has seen rapid shale gas exploration and development over the last five years,successively achieving breakthroughs and important findings in many areas and strata.The details are as follows.(1)Large-scale development of middle-shallow shale gas(burial depth:less than 3500 m)has been realized,with the productivity having rapidly increased;(2)breakthroughs have been constantly made in the development of deep shale gas(burial depth:3500-4500 m),and the ultradeep shale gas(burial depth:greater than 4500 m)is under testing;(3)breakthroughs have been made in the development of normal-pressure shale gas,and the assessment of the shale gas in complex tectonic areas is being accelerated;(4)shale gas has been frequently discovered in new areas and new strata,exhibiting a great prospect.Based on the exploration and development practice,three aspects of consensus have been gradually reached on the research progress in the geological theories of shale gas achieved in China.(1)in terms of deep-water fine-grained sediments,organic-rich shales are the base for the formation of shale gas;(2)in terms of high-quality reservoirs,the development of micro-nano organic matter-hosted pores serves as the core of shale gas accumulation;(3)in terms of preservation conditions,weak structural transformation,a moderate degree of thermal evolution,and a high pressure coefficient are the key to shale gas enrichment.As a type of important low-carbon fossil energy,shale gas will play an increasingly important role in achieving the strategic goals of peak carbon dioxide emissions and carbon neutrality.Based on the in-depth study of shale gas geological conditions and current exploration progress,three important directions for shale gas exploration in China in the next five years are put forward.

The mechanism of unconventional hydrocarbon formation: Hydrocarbon self-sealing and intermolecular forces

The successful development of unconventional hydrocarbons has significantly increased global hydrocarbon resources, promoted the growth of global hydrocarbon production and made a great breakthrough in classical oil and gas geology. The core mechanism of conventional hydrocarbon accumulation is the preservation of hydrocarbons by trap enrichment and buoyancy, while unconventional hydrocarbons are characterized by continuous accumulation and non-buoyancy accumulation. It is revealed that the key of formation mechanism of the unconventional reservoirs is the self-sealing of hydrocarbons driven by intermolecular forces. Based on the behavior of intermolecular forces and the corresponding self-sealing, the formation mechanisms of unconventional oil and gas can be classified into three categories:(1) thick oil and bitumen, which are dominated by large molecular viscous force and condensation force;(2) tight oil and gas, shale oil and gas and coal-bed methane, which are dominated by capillary forces and molecular adsorption;and(3) gas hydrate, which is dominated by intermolecular clathration. This study discusses in detail the characteristics, boundary conditions and geological examples of self-sealing of the five types of unconventional resources, and the basic principles and mathematical characterization of intermolecular forces. This research will deepen the understanding of formation mechanisms of unconventional hydrocarbons, improve the ability to predict and evaluate unconventional oil and gas resources, and promote the development and production techniques and potential production capacity of unconventional oil and gas.

Geomorphosite Valorization a View to Sustainable Development: Case of Ait Hajji, Oued Boulahmayel Valley, Central Morocco

The Pleistocene Fluvial-lacustrine of Ait Hajji Formation is located in South East of Tiddas, and in the Qua-ternary deposits of the Moroccan Central Plateau. These outcrops represent on a geomorphosite of great im-portance for the study of geological heritage, and for a natural eco-tourism valorization in Morocco. For to aim a natural tourism promotion, for indigenous peoples, this geomorphosite in question has an fluorescent and dense flora with a diversified fauna in the heart of one Ordovician quartzite bar and Devonian limestone ridges. In Oued Boulahmayel geomorphosite contains a memory geological Formation of a Pleistocene epi-sode, beginning firstly by a dynamic fluviatil land synchronous with a local volcanic activity (Phonolite ne-phelinc) replaced by a lake sedimentation related to the formation of a dam natural, created a few hundred meters downstream from Boulahmayel. For valorizing of the hinterland of the plains towns, it is necessary to develop a geo-eco-tourism integrated who provide its harvest and will argue the benefits resources of rural people of high-mountains in their own environment. It is proposed in the perspective to initiate a sustainable development approach, while ensuring the conservation and ensure the continued natural existence of the surroundings environments and to appreciate the potential of the region. Thus that beauty hidden in the hin-terland upstream to a tourist eager for discoveries, to encourage them to practice their stay as short as it is, in a safe space and very quiet. In order to materialize the concept of geo-eco-tourism, we must deploy the ef-forts of local people, policy makers and scientists in order to produce tourist maps with different interesting routes, to implant signal panels, to develop tracks campsites and trails within the forests, creating shelters and rest houses in private homes, as well as provide training for specialized guide’s rescuers.

Efficient development strategies for large ultra-deep structural gas fields in China

Through analyzing the development of large ultra-deep structural gas fields in China,strategies for the efficient development of such gas fields are proposed based on their geological characteristics and production performance.According to matrix properties,fracture development degree and configuration between matrix and fractures,the reservoirs are classified into three types:single porosity single permeability system,dual porosity dual permeability system,and dual porosity single permeability system.These three types of gas reservoirs show remarkable differences in different scales of permeability,the ratio of dynamic reserves to volumetric reserves and water invasion risk.It is pointed out that the key factors affecting development efficiency of these gas fields are determination of production scale and rapid identification of water invasion.Figuring out the characteristics of the gas fields and working out pertinent technical policies are the keys to achieve efficient development.The specific strategies include reinforcing early production appraisal before full scale production by deploying high precision development seismic survey,deploying development appraisal wells in batches and scale production test to get a clear understanding on the structure,reservoir type,distribution pattern of gas and water,and recoverable reserves,controlling production construction pace to ensure enough evaluation time and accurate evaluation results in the early stage,in line with the development program made according to the recoverable reserves,working out proper development strategies,optimizing pattern and proration of wells based on water invasion risk and gas supply capacity of matrix,and reinforcing research and development of key technologies.

Oil oxidation in the whole temperature regions during oil reservoir air injection and development methods

The oil oxidation characteristics of the whole temperature regions from 30 ℃ to 600 ℃ during oil reservoir air injection were revealed by experiments. The whole oil oxidation temperature regions were divided into four different parts: dissolving and inflation region, low temperature oxidation region, medium temperature oxidation region and high temperature oxidation region. The reaction mechanisms of different regions were explained. Based on the oil oxidation characteristics and filed tests results, light oil reservoirs air injection development methods were divided into two types: oxygen-reducing air flooding and air flooding;heavy oil reservoirs air injection in-situ combustion development methods were divided into two types: medium temperature in-situ combustion and high temperature in-situ combustion. When the reservoir temperature is lower than 120 ℃, oxygen-reducing air flooding should be used for light oil reservoir development. When the reservoir temperature is higher than 120 ℃, air flooding method should be used for light oil reservoir development. For a normal heavy oil reservoir, when the combustion front temperature is lower than 400 ℃, the development method is medium temperature in-situ combustion. For a heavy oil reservoir with high oil resin and asphalting contents, when the combustion front temperature is higher than 450 ℃, the development method at this condition is high temperature in-situ combustion. Ten years field tests of air injection carried out by PetroChina proved that air has advantages in technical, economical and gas source aspects compared with other gas agents for oilfield gas injection development. Air injection development can be used in low/super-low permeability light oil reservoirs, medium and high permeability light oil reservoirs and heavy oil reservoirs. Air is a very promising gas flooding agent.

Transcriptional mechanisms regulating gene expression and determining cell fates in plant development

Transcriptional regulatory mechanisms that control transcriptional regulators, target genes, and their interactions provide new insights into general development processes throughout the life cycle of the plant. Although different molecular mechanisms that regulate plant growth and development have been identified, detailed transcriptional mechanisms that control gene expression, modulate developmental programmes, and determine cell fates in plant development are not fully understood. To increase our understanding on transcriptional mechanisms regulating diverse processes in plant development, we have reviewed the regulation of transcription during the process of development including transcriptional mechanisms regulating root, stem, leaf, flower, seed, embryo, endosperm, ovule, fruit, and chloroplast development. We have summarized the interaction, expression, transport, signaling events of transcriptional regulators and their targets in a number of model plants and highlighted the involvement of hormones and microRNAs in plant development. Understanding the precise transcriptional mechanisms regulating gene expression in plant development will be valuable for plant molecular breeding.