A review of underlying topography estimation over forest areas by In SAR: Theory, advances, challenges and perspectives

The paramount importance and multi-purpose applications of underlying topography over forest areas have gained widespread recognition over recent decades, bringing about a variety of experimental studies on accurate underlying topography mapping. The highly spatial and temporal dynamics of forest scenarios makes traditional measuring techniques difficult to construct the precise underlying topography surface. Microwave remote sensing has been demonstrated as a promising technique to retrieve the underlying topography over large areas within a limited period, including synthetic aperture radar interferometry(InSAR), polarimetric InSAR(PolInSAR) and tomographic SAR(TomoSAR). In this paper, firstly, the main principle of digital elevation model(DEM) generation by InSAR and SAR data acquisition over forest area are introduced. Following that, several methods of underlying topography extraction based on InSAR, PolInSAR, and TomoSAR are introduced and analyzed, as well as their applications and performance are discussed afterwards. Finally, four aspects of challenge are highlighted, including SAR data acquisition, error compensation and correction, scattering model reconstruction and solution strategy of multi-source data, which needs to be further addressed for robust underlying topography estimation.

The influence of different underlying surface on sand-duststorm in northern China

In this paper, a quantitative research on the relationship between different underlying surface and sand-dust storm has been made by using 40 years meteorological data of five different types of underlying surface in northern China, which include farmland, grassland, sandland, gobi and salt crust. These metrological data comprise sand-dust storm days and strong wind days. By analyzing, we can find that there are certain correlations between the days of sand-dust storm and strong wind for different underlying surface, which has great influence on sand-dust storm. But there are pronounced differences in different types of underlying surface. The sand-dust storm days of grassland, gobi and salt crust, with smaller interannual variation are obviously less than strong wind days. On the other hand, the sand-dust storm days of farmland and sandland increase evidently, even in many years, are much more than strong wind days. The differences are mainly induced by the influencing mechanism of different underlying surface on sand-dust storm. Grassland, gobi and salt crust with stable underlying surface are not prone to sand-dust storm under strong wind condition. Whereas, the underlying surface of farmland and sandland is unstable, that is easy to induce sand-dust storm under strong wind condition.

Review on simulation of land-surface processes on the Tibetan Plateau

The Tibetan Plateau(TP) has powerful dynamics and thermal effects, which makes the interaction between its land and atmosphere significantly affect climate and environment in the regional or global area. By retrospecting the latest research progress in the simulation of land-surface processes(LSPs) over the past 20 years, this study discusses both the simulation ability of land-surface models(LSMs) and the modification of parameterization schemes from two perspectives, the models' applicability and improved parameterization schemes. Our review suggests that different LSMs can well capture the spatiotemporal variations of the physical quantities of LSPs; but none of them can be fully applied to the plateau, meaning that all need to be revised according to the characteristics specific to the TP. Avoiding the unstable iterative computation and determining the freeze-thaw critical temperature according to the thermodynamic equilibrium equation, the unreasonable freeze-thaw parameterization scheme can be improved. Due to the complex underlying surface of the TP, no parameterization scheme of roughness length can well simulate the various characteristics of the turbulent flux over the TP at different temporal scales. The uniform soil thermodynamic and hydraulic parameterization scheme is unreasonable when it is applied to the plateau, as a result of the strong soil heterogeneity. There is little research on the snow-cover process so far,and the improved scheme has no advantage over the original one due to the lack of some related physical processes. The constant interaction among subprocesses of LSPs makes the improvement of a multiparameterization scheme yield better simulation results. According to the review of existing research, adding high-quality observation stations, developing a parameterization scheme suitable for the special LSPs of the TP, and adjusting the model structures can be helpful to the simulation of LSPs on the TP.

Additive manufacturing of magnesium and its alloys: process-formabilitymicrostructure-performance relationship and underlying mechanism

Magnesium and its alloys,as a promising class of materials,is popular in lightweight application and biomedical implants due to their low density and good biocompatibility.Additive manufacturing(AM)of Mg and its alloys is of growing interest in academia and industry.The domain-by-domain localized forming characteristics of AM leads to unique microstructures and performances of AM-process Mg and its alloys,which are different from those of traditionally manufactured counterparts.However,the intrinsic mechanisms still remain unclear and need to be in-depth explored.Therefore,this work aims to discuss and analyze the possible underlying mechanisms regarding defect appearance and elimination,microstructure formation and evolution,and performance improvement,based on presenting a comprehensive and systematic review on the relationship between process parameters,forming quality,microstructure characteristics and resultant performances.Lastly,some key perspectives requiring focus for further progression are highlighted to promote development of AM-processed Mg and its alloys and accelerate their industrialization.

ANNUAL VARIATIONS OF TEMPERATURE ON FOUR URBAN UNDERLYING SURFACES AND FITTING ANALYSIS

Based on the observed 2-year temperature data for four kinds of typical urban underlying surfaces,including asphalt, cement, bare land and grass land, the annual variations and influencing factors of landsurface temperature are analyzed. Then fitting equations for surface temperature are established. It is shownthat the annual variation of daily average, maximum and minimum temperature and daily temperature rangeon the four urban underlying surfaces is consistent with the change in air temperature. The difference oftemperature on different underlying surfaces in the summer half year (May to October) is much moreevident than that in the winter half year (December to the following April). The daily average and maximumtemperatures of asphalt, cement, bare land and grass land are higher than air temperature due to theatmospheric heating in the daytime, with that of asphalt being the highest, followed in turn by cement, bareland and grass land. Moreover, the daily average, maximum and minimum temperature on the four urbanunderlying surfaces are strongly impacted by total cloud amount, daily average relative humidity andsunshine hours. The land surface can be cooled (warmed) by increased total cloud amount (relativehumidity). The changes in temperature on bare land and grass land are influenced by both the total cloudamount and the daily average relative humidity. The temperature parameters of the four land surfaces aresignificantly correlated with daily average, maximum and minimum temperature, sunshine hours, dailyaverage relative humidity and total cloud amount, respectively. The analysis also indicates that the range offitting parameter of a linear regression equation between the surface temperature of the four kinds of typicalland surface and the air temperature is from 0.809 to 0.971, passing the F-test with a confidence level of 0.99.

Streptozotocin induced Alzheimer's disease like changes and the underlying neural degeneration and regeneration mechanism

Alzheimer’s disease（AD）is a neurodegenerative disorder which is remarkably characterized by pathological hallmarks that include neurofibrillary tangles,neuronal loss extracellular senile plaques containing aggregated amyloid beta（Aβ）,and neurofibrillary tangles composed of the hyperphosphorylated form of the microtubule protein tau.It is the most common form of dementia which is characterized by severe neurodegenerative changes such as loss of neurons and synapses in brain（Kamat et al.,2014）.

Mechanisms underlying the promotion of functional recovery by deferoxamine after spinal cord injury in rats

Deferoxamine, a clinically safe drug used for treating iron overload, also repairs spinal cord injury although the mechanism for this action remains unknown. Here, we determined whether deferoxamine was therapeutic in a rat model of spinal cord injury and explored potential mechanisms for this effect. Spinal cord injury was induced by impacting the spinal cord at the thoracic T10 vertebra level. One group of injured rats received deferoxamine, a second injured group received saline, and a third group was sham operated. Both 2 days and 2 weeks after spinal cord injury, total iron ion levels and protein expression levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1β and the pro-apoptotic protein caspase-3 in the spinal cords of the injured deferoxamine-treated rats were significantly lower than those in the injured saline-treated group. The percentage of the area positive for glial fibrillary acidic protein immunoreactivity and the number of terminal deoxynucleotidyl transferase d UTP nick end labeling-positive cells were also significantly decreased both 2 days and 2 weeks post injury, while the number of Neu N-positive cells and the percentage of the area positive for the oligodendrocyte marker CNPase were increased in the injured deferoxamine-treated rats. At 14–56 days post injury, hind limb motor function in the deferoxamine-treated rats was superior to that in the saline-treated rats. These results suggest that deferoxamine decreases total iron ion, tumor necrosis factor-α, interleukin-1β, and caspase-3 expression levels after spinal cord injury and inhibits apoptosis and glial scar formation to promote motor function recovery.

Mild closed head traumatic brain injury-induced changes in monoamine neurotransmitters in the trigeminal subnuclei of a rat model:mechanisms underlying orofacial allodynias and headache

Our recent findings have demonstrated that rodent models of closed head traumatic brain injury exhibit comprehensive evidence of progressive and enduring orofacial allodynias, a hypersensitive pain response induced by non-painful stimulation. These allodynias, tested using thermal hyperalgesia, correlated with changes in several known pain signaling receptors and molecules along the trigeminal pain pathway, especially in the trigeminal nucleus caudalis. This study focused to extend our previous work to investigate the changes in monoamine neurotransmitter immunoreactivity changes in spinal trigeminal nucleus oralis, pars interpolaris and nucleus tractus solitaries following mild to moderate closed head traumatic brain injury, which are related to tactile allodynia, touch-pressure sensitivity, and visceral pain. Our results exhibited significant alterations in the excitatory monoamine, serotonin, in spinal trigeminal nucleus oralis and pars interpolaris which usually modulate tactile and mechanical sensitivity in addition to the thermal sensitivity. Moreover, we also detected a robust alteration in the expression of serotonin, and inhibitory molecule norepinephrine in the nucleus tractus solitaries, which might indicate the possibility of an alteration in visceral pain, and existence of other morbidities related to solitary nucleus dysfunction in this rodent model of mild to moderate closed head traumatic brain injury. Collectively, widespread changes in monoamine neurotransmitter may be related to orofacial allodynhias and headache after traumatic brain injury.

Current view of neurotransmitter changes underlying tinnitus

Tinnitus is the perception of a monotonous sound not present in the environment. Nearly 20% of the U.S. population suffers from tinnitus, and tinnitus has been reported to be the most prevalent service-connected disability of all U.S. veterans （Henry et al., 2005; Eggermont, 2012; Veterans Benefits Administration, 2014）. Many types of peripheral injury have been understood to induce tinnitus, including damage to the cochlea by intense sound or ototoxic medications and destruction of the auditory nerve by cochlear ablation or nerve transection （Lee and God- frey, 2014）. The pathophysiological mechanisms by which tin- nitus develops are only poorly understood. In order to further clarify the pathogenesis, a need has been expressed for a better understanding of the rebalancing of excitatory and inhibitory signaling mechanisms that occur after peripheral injury （Gold and Bajo, 2014）. One of the current, prominent hypotheses of tinnitus development is that, after being triggered by peripheral injury, tinnitus may result from a maladaptation of the central auditory system to this peripheral dysfunction （Auerbach et al., 2014）, and that one of the mechanisms by which this occurs is a decrease in inhibitory neurotransmission. The major struc- tures that play a role in transmitting neural activity through the ascending central auditory system include the cochlear nucleus and superior olivary complex of the pons-medulla region, the inferior colliculus of the midbrain, the medial geniculate nude- us of the thalamus, and the auditory cortex.

The evapotranspiration and environmental controls of typical underlying surfaces on the Qinghai-Tibetan Plateau

To reveal the characteristics of evapotranspiration and environmental control factors of typical underlying surfaces(alpine wetland and alpine meadow)on the Qinghai-Tibetan Plateau,a comprehensive study was performed via in situ observations and remote sensing data in the growing season and non-growing season.Evapotranspiration was positively correlated with precipitation,the decoupling coefficient,and the enhanced vegetation index,but was energy-limited and mainly controlled by the vapor pressure deficit and solar radiation at an annual scale and growing season scale,respectively.Compared with the non-growing season,monthly evapotranspiration,equilibrium evaporation,and decoupling coefficient were greater in the growing season due to lower vegetation resistance and considerable precipitation.However,these factors were restricted in the alpine meadow.The decoupling factor was more sensitive to changes of conductance in the alpine wetland.This study is of great significance for understanding hydro-meteorological processes on the Qinghai-Tibetan Plateau.

Analysis on Thermal Environment of Underlying Surface and PM2.5 Concentration in Community Park of Beijing in Winter

Community park is one of the most important landscape spaces for urban people to live outdoors,and people’s perception of environmental microclimate is a direct factor affecting the use frequency and experience of community parks.In this paper,Shijingshan Sculpture Park of Beijing was taken as experimental object.Using the method of fi eld measurement,9-d winter test for 3 months was conducted in three kinds of landscape architecture spaces,including waterfront plaza,open green space and square under the forest.Via regression analysis method,the measured air temperature(Ta),relative humidity of air(RH),particulate matter(PM2.5)were analyzed.It is found that winter sunshine is main infl uence factor of garden microclimate,and there is a negative correlation between local temperature and humidity;local temperature and humidity can regulate the local PM2.5 concentration,and temperature shows negative correlation with PM2.5 concentration,while humidity shows positive correlation with PM2.5 concentration.Meanwhile,via comparative analysis of temperature,humidity and PM2.5 concentration in different types of garden spaces,the infl uence of different space forms,planting forms and materials on thermal environment of underlying surface and PM2.5 concentration was summarized,and design strategy was optimized,to be as benefi cial reference of reconstruction design of community parks.

Underlying Beliefs Influencing Vietnamese Nurses and Doctors in Screening for Victims of Domestic Violence: An Exploratory Study

Many health professionals in Vietnam have limited knowledge and experience in coordinating care for victims of Domestic Violence (DV). This qualitative study aimed to elicit the beliefs of nurses and doctors that are influencing the care of victims of DV. Data were collected by semi-structured interviews with nineteen nurses and doctors. Data were analyzed by content analysis and organized by three main themes;behavioral beliefs, normative beliefs and control beliefs. The outcomes of this study will inform the development of intervention strategies that will enable health professionals to better respond to and manage care for women who experience domestic violence in Vietnam.

Effect of the Gut Microbiota on Obesity and Its Underlying Mechanisms: an Update

Obesity has become one of the most prevalent health issues of our time. According to a 2012 WHO report, around 3.4 million adults die each year as a result of being overweight or obese. Humans are in fact superorganisms composed of both human and microbial cells with 2 sets of genes, those encoded in our own genome and those encoded in our microbiota. All these cells and genes have the potential to influence our health.

Numerical simulation on pressure-relief deformation characteristics of underlying coal-rock mass after upper protective layer excavation

Based on the occurrence features of Group B coal-seams at a coal mine in the Huainan coal mining area, the elasto-plastic mechanical damage constitutive functions and numerical model for the protective layer excavation were established. With the UDEC2D computer program, after the upper protective layer was mined, the stress field change trends, crack development, and expansion deformation trends of underlying coal rock seams in the floor of the working face were simulated and analyzed. The simulation results show the stress changes in coal rock seams, the evolution process of pre-cracks during the process of upper protective layer mining, the caved zone and fractured zone of the underlying coal rock seams. At the same time, the results from the actual investigation and analysis of protected layer deformation match the simulation values, which verifies the validity and accuracy of numerical simulation results. The study results have an important guiding significance for gas management in low permeability and high gas coal seams with similar mining conditions.

Evidence for Multiple Underlying Fermi Surface and Isotropic Energy Gap in the Cuprate Parent Compound Ca2CuO2Cl2

The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mechanism of high temperature superconductivity.A natural starting point is to elucidate the basic electronic structure of the parent compound.Here we report comprehensive high resolution angle-resolved photoemission measurements on Ca_2CuO_2Cl_2,a Mott insulator and a prototypical parent compound of the cuprates.Multiple underl.ying Fermi surface sheets are revealed for the first time.The high energy waterfall-like band dispersions exhibit different behaviors near the nodal and antinodal regions.Two distinct energy scales are identified：a d-wave-like low energy peak dispersion and a nearly isotropic lower Hubbard band gap.These observations provide new information of the electronic structure of the cuprate parent compound,which is important for understanding the anomalous physical properties and superconductivity mechanism of the high temperature cuprate superconductors.

Comparative study of surface energy and land-surface parameters in different climate zones in Northwest China

Based on observational data of arid,semi-arid and semi-humid areas in Northwest China,the characteristics of surface-wa ter heat transfer and land-surface parameters were compared and analyzed.The results show that the annual mean net radi ation was largest in the semi-humid area,followed by the semi-arid area,and then the arid area:77.72 W/m^2,67.73 W/m^2,and 55.47 W/m^2,respectively.The annual mean sensible heat flux was largest in the arid area,followed by the semi-arid and semi-humid areas,while latent heat flux showed the reverse.The annual mean sensible heat flux in arid,semi-arid,and semi-humid areas was 85.7 W/m^2,37.59 W/m^2,and 27.55 W/m^2,respectively.The annual mean latent heat flux was 0 W/m^2,26.08 W/m^2,and 51.19 W/m2,respectively.The annual mean soil-heat flux at the 5-cm soil layer in arid,semi-arid,and semi-humid areas was 1.00 W/m^2,0.82 W/m^2,and 1.25 W/m^2,respectively.The annual mean surface albedo was larg est in the arid area,followed by the semi-humid area;and the smallest was in the semi-arid area:0.24,0.21,and 0.18,re spectively.The annual mean Bowen ratio in the semi-arid area was about 2.06,and that in semi-humid area was about 0.03.The annual mean soil thermal conductivity in the arid,semi-arid,and semi-humid areas was 0.26 W/(m k),1.15 W/(m k),and 1.20 W/(m k),respectively.

Underlying mechanisms and clinical potential of circRNAs in glioblastoma

Glioblastoma(GBM)is the most malignant form of glioma and is difficult to diagnose,leading to high mortality rates.Circular RNAs(circRNAs)are noncoding RNAs with a covalently closed loop structure.CircRNAs are involved in various pathological processes and have been revealed to be important regulators of GBM pathogenesis.CircRNAs exert their biological effects by 4 different mechanisms:serving as sponges of microRNAs(miRNAs),serving as sponges of RNA binding proteins(RBPs),modulating parental gene transcription,and encoding functional proteins.Among the 4 mechanisms,sponging miRNAs is predominant.Their good stability,broad distribution and high specificity make circRNAs promising biomarkers for GBM diagnosis.In this paper,we summarized the current understanding of the characteristics and action mechanisms of circRNAs,illustrated the underlying regulatory mechanisms of circRNAs in GBM progression and explored the possible diagnostic role of circRNAs in GBM.

Study on Numerical Simulation of the Impact of the Land-Surface Process in a Meiyu Front Rainstorm

[Objective] The research aimed to carry out numerical simulation on impact of land-surface process in a Meiyu front rainstorm.[Method] Based on the meso-scale atmospheric non-hydrostatic model GRAPES-Meso which coupled with NOAH land-surface module,a Meiyu front rainstorm in Jianghuai basin during 6-8 July,2005 was simulated.Via sensitivity tests with and without land-surface process,the impact of land-surface process on Meiyu front rainstorm was studied.[Result] GRAPES-Meso which coupled with NOAH land-surface process could simulate daily variation characteristics of Meiyu front precipitation and atmospheric low-level southwest jet.The land-surface process could improve the simulations of precipitation initiation,intensity and distribution.The improvement of precipitation initiation simulation was especially obvious,which solved spin-up problem of model to some extent.When the land-atmosphere interaction wasn’t considered,the precipitation initiation of model was very slow.The intensity evolution of simulated precipitation was different from actual situation.Moreover,it couldn’t simulate daily variation characteristics of precipitation and southwest jet.[Conclusion] The land-surface process had important impact on Meiyu process in Jianghuai basin.

MECHANISMS UNDERLYING PRESSOR EFFECT OF ELECTROACUPUNCTURE:Ⅰ.ESSENTIAL NEURAL SUBSTRATES IN BRAIN

The electroacupuncture(EA)being delivered to“Zusanli-Sanyinjiao”acupomts reduced a pressor-tachycardia effect,this effect still remained(nearly unchanged)after decerebration between superior and inferior colliculus,indicating that the essential cen-tets of EA-pressor effect(EA-PE)are located in lower brain stem.The EA-PE could be at-tenuated by preinjection of atropine or phentolamine bilaterally into rostral ventrolateralmedulla(RVL)(but was not significantly influenced by propranolol or haloperidol).Elec-trolytic lesions of bilateral nucleus parabrachialis(NPB),reduced the EA-PE,while lesionof the area postrema did not.Taken together with our previous results that lesions of bilateral locus coeruleus(LC)also remarkably decreased the EA-PE,α-adrenoceptors in RVL mediated NPB-pressor re-sponse,and both α-adrenoceptors,M-cholinoceptors are involved in LC-pressor response:the present results indicate that activation of NPB-RVL(α-receplor)and LC-RVL(α-and Mreceptor)pressor system by EA is the essential central mechanism underlying EA-PE.

Comparison of different land-surface perturbation methods in short-range ensemble forecasts

In order to compare the sensitivity of short-range ensemble forecasts to different land-surface parameters in the South China region,three perturbation experiments related to the land surface model(LSM),initial soil moisture(ISM),and land–atmosphere coupling coefficient(LCC)were designed,and another control experiment driven by the Global Ensemble Forecast System(GEFS)was also performed.All ensemble members were initiated at 0000 UTC each day,and integrated for 24 h for a total of 40 days from the period 1 April to 10 May 2019 based on the Weather Research and Forecasting model.The results showed that the perturbation experiment of the LSM(LSMPE)had the largest ensemble spread,as well as the lowest ensemble-mean root-mean-square error among the three sets of land-surface perturbed experiments,which indicated that it could represent more uncertainty and less error.The ensemble spread of the perturbation experiment of the ISM(ISMPE)was generally less than that of LSMPE but greater than that of LCCPE(the perturbation experiment of the LCC).In particular,although the perturbation of the LCC could not produce greater spread,it had an effective influence on the intensity of precipitation.However,the ensemble spread of all the land-surface perturbed experiments was smaller than that of GEFSPE(the control experiment).Therefore,in future,land-surface perturbations and atmospheric perturbations should be combined in the design of ensemble forecasting systems to make the model represent more uncertainties.