基于深度学习的区域生态安全时空模拟与预测

区域作为人类、自然、社会共同作用和互相影响的复杂系统,对区域进行生态量化建模与模拟仿真,是实现区域可持续发展战略的关键。传统机器学习方法对区域生态系统建模取得了一定的成果,但难以确定学习特征和实现时空模拟。深度学习不需事先确定训练特征,具有优异的特征学习能力,能够提高模型预测精度,因此利用深度学习进行建模具有显著优势。本文使用植被净初级生产力（NPP）、气溶胶光学厚度（AOD）和人口格网数据,充分利用深度学习的优点,采用最优深度神经网络时空模拟,得到了河南省2007-2014年3 km分辨率的生态赤字空间分布图和河南省2015-2020年的生态赤字时间预测结果并进行分析,为区域生态的科学管理和建设供科学依据和参考。     

Uplift in seismic response of pile supported buildings

To resist seismic overturning moments piles are often designed for tensile forces which require pile connection to the cap and sometimes, socketing. For typical buildings, this paper theoretically examines the effect of these measures on seismic response, forces and pile loading in dependence on pile numbers, configuration and tip conditions.     

Land desertification and restoration in Middle East and North Africa (MENA) region

The Middle East and North Africa (MENA) region is characterized by high population growth, degraded and fragile nat-ural ecosystems, and a limited amount of arable lands. It is one of the most water-sc...     

Radiation transfer in inhomogeneous dispersive media

Equations for the angular density of radiation, reflected and transmitted intensities associated with radiation scattered by inhomogeneous dispersive media are obtained. The Padé approximant technique is used to calculate these intensities in inhomogeneous and homogeneous media. The results for the [0/1] Padé approximant lead to numerical results that compared with the exact results.     

NanoSIMS analysis of organic carbon from the Tissint Martian meteorite: Evidence for the past existence of subsurface organic‐bearing fluids on Mars

Two petrographic settings of carbonaceous components, mainly filling open fractures and occasionally enclosed in shock‐melt veins, were found in the recently fallen Tissint Martian meteorite. The presence in shock‐melt veins and the deuterium enrichments (δD up to +1183‰) of these components clearly indicate a pristine Martian origin. The carbonaceous components are kerogen‐like, based on micro‐Raman spectra and multielemental ratios, and were probably deposited from fluids in shock‐induced fractures in the parent rock of Tissint. After precipitation of the organic matter, the rock experienced another severe shock event, producing the melt veins that encapsulated a part of the organic matter. The C isotopic compositions of the organic matter (δ¹³C = ?12.8 to ?33.1‰) are significantly lighter than Martian atmospheric CO₂ and carbonate, providing a tantalizing hint for a possible biotic process. Alternatively, the organic matter could be derived from carbonaceous chondrites, as insoluble organic matter from the latter has similar chemical and isotopic compositions. The presence of organic‐rich fluids that infiltrated rocks near the surface of Mars has significant implications for the study of Martian paleoenvironment and perhaps to search for possible ancient biological activities on Mars.     

Parameters affect foaming and foam stability during foam drilling

The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.     

Geological and geophysical investigation of Kamil crater,Egypt

Abstract– We detail the Kamil crater (Egypt) structure and refine the impact scenario, based on the geological and geophysical data collected during our first expedition in February 2010. Kamil Crater is a model for terrestrial small‐scale hypervelocity impact craters. It is an exceptionally well‐preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and target rocks comprising subhorizontally layered sandstones. The high depth‐to‐diameter ratio of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45°. Newly identified asymmetries, including the off‐center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well‐preserved craters. Geomagnetic data reveal no buried individual impactor masses >100 kg and suggest that the total mass of the buried shrapnel >100 g is approximately 1050–1700 kg. Based on this mass value plus that of shrapnel >10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t.     

Does salinity change determine zooplankton variability in the saline Qarun Lake(Egypt)?

Zooplankton and 14 abiotic variables were studied during August 2011 at 10 stations in Lake Qarun,Egypt.Stations with the lowest salinity and highest nutrient concentrations and turbidity were close to the discharge of waters from the El-Bats and El-Wadi drainage systems.A total of 15 holozooplankton species were identified.The salinity in Lake Qarun increased and fluctuated since 1901:12 g/L in 1901;8.5 g/L in 1905;12.0 g/L in 1922;30.0 g/L in 1985;38.7 g/L in 1994;35.3 g/L in 2006,and 33.4 g/L in 2011.The mean concentration of nutrients(nitrate,nitrite and orthophosphate) gradually increased from 35,0.16 and 0.38 ? g/L,respectively,in 1953–1955 to 113,16.4,and 30.26 ? g/L in 2011.From 1999–2003 some decrease of species diversity occurred.Average total zooplankton density was 30 000 ind./m 3 in 1974–1977;356 125 ind./m 3 in 1989;534 000 ind./m 3 in 1994–1995;from 965 000 to 1 452 000 ind./m 3 in 2006,and 595 000 ind./m 3 in 2011.A range of long-term summer salinity variability during the last decades was very similar to a range of salinity spatial variability in summer 2011.There is no significant correlation between zooplankton abundance and salinity in spatial and long-term changes.We conclude that salinity fluctuations since at least 1955 did not directly drive the changes of composition and abundance of zooplankton in the lake.A marine community had formed in the lake,and it continues to change.One of the main drivers of this change is a regular introduction and a pressure of alien species on the existent community.Eutrophication also plays an important role.The introduction of Mnemiopsis leidyi,first reported in 2014,may lead to a start of a new stage of the biotic changes in Lake Qarun,when eutrophication and the population dynamics of this ctenophore will be main drivers of the ecosystem change.     

Discovery of the causeway and the mortuary temple of the Pyramid of Amenemhat II using near‐surface magnetic investigation,Dahshour, Giza,Egypt

The main outbuildings of the Amenemhat II pyramid complex in Dahsour were yet to be discovered due to a very long subjection of the area to the military authorities and also the demolition of the pyramid itself. We describe the discovery of some of these outbuildings using near‐surface magnetic investigations. A gradiometer survey was conducted in the area east of the pyramid to measure the vertical magnetic gradient with a high resolution instrument at 0.5 m sampling interval. The data showed some undesirable field effects such as grid discontinuities, grid slope, traverse stripe effects, spikes and high frequencies originating from recent ferrous contamination. These undesirable effects were addressed to produce an enhanced display. We have successfully detected four main structures in the area east of the pyramid; the causeway that connected the mortuary temple with the valley temple during the Middle Kingdom of the 12^th Dynasty, the mortuary temple and its associated rooms, ruins of an ancient working area and an Egyptian‐style tomb structure called a Mastaba. An improved recognition for these structures was accomplished by using the analytic signal and Euler deconvolution techniques. Excavation of a small part within the study area has proven the reliability of magnetic discoveries and the shallowness and composition of the detected features.