A Novel Clutter Suppression Algorithm for Low-Slow-Small Targets Detecting Based on Sparse Adaptive Filtering

Passive detection of low-slow-small(LSS)targets is easily interfered by direct signal and multipath clutter,and the traditional clutter suppression method has the contradiction between step size and convergence rate.In this paper,a frequency domain clutter suppression algorithm based on sparse adaptive filtering is proposed.The pulse compression operation between the error signal and the input reference signal is added to the cost function as a sparsity constraint,and the criterion for filter weight updating is improved to obtain a purer echo signal.At the same time,the step size and penalty factor are brought into the adaptive iteration process,and the input data is used to drive the adaptive changes of parameters such as step size.The proposed algorithm has a small amount of calculation,which improves the robustness to parameters such as step size,reduces the weight error of the filter and has a good clutter suppression performance.

Effects of site preparation methods on soil physical properties and outplanting success of coniferous seedlings in boreal forests

This study assessed the effect of patch scarification and mounding on the physical properties of the root layer and the success of tree planting in various types of forests.This study was conducted on 12 forest sites in taiga forests of the European part of Russia.A total of 54 plots were set up to assess seedling survival;root collar diameter,height,and heigh increment were measured for 240 seedlings to assess growth.In the rooting layer,240 soil samples were taken to determine physical properties.The study showed that soil treatment methods had no effect on bulk density and total porosity in Cladina sites.However,reduced soil moisture was noted,particularly in mounds,resulting in increased aeration.In Myrtillus sites,there were increased bulk density,reduced soil moisture,and total porosity in the mounds.Mounding treatment in Polytrichum sites resulted in reduced soil moisture and increased aeration porosity.In the Myrtillus and Polytrichum sites,patch scarification had no effects on physical properties.In Polytrichum sites,survival rates,heights,and heigh increments of bareroot Norway spruce seedlings in mounds were higher than in patches;however,the same did not apply to diameter.In Cladina and Myrtillus sites,there was no difference in growth for bareroot and containerised seedlings with different soil treatments.Growing conditions and soil types should be considered when applying different soil treatment methods to ensure high survival rates and successful seedling growth.

Consequences of Future Expansion at the Arctic Treeline in Northernmost Norway

Seedlings from eight seed populations of mountain birch(Betula pubescens var.tortuosa),were transplanted to a site close to the town Vard?,in the Arctic part of the Varanger area in Northernmost Norway,in order to investigate the adaptation to climate change in different birch provenances and the implications for the treeline ecosystem and the local population.A comparable site was established at Kilpisj?rvi(500 masl)in Northern Finland close to treeline.Five replicates with 20 plants per replicate were established per site.The Vard?site was partly snow-free,sheltered by a willow thicket,and partly exposed on a ditched peat bog with thick snow cover from a nearby snowfence.Annual measurements were carried out on survival and growth parameters.The preliminary conclusion from this study is that local climate may be more important than the overall climatic variation in the adaptation and reforestation process in Northernmost Fennoscandia.In this process,the subarctic willow and shrub vegetation seems to be an important factor influencing the microclimate and seedling establishment.Species and provenances originating from areas with similar latitudes and climatic conditions as the reforestation area,were most successful.The Varanger area has always been a meeting place between different cultures,i.e.,the Sami,Norwegian,Finnish and Russian population.The study indicates that in a changed climate the birch forest area would expand because there will be more willow growth and consequently more safe sites for birch seedling establishment and growth,which would also create a better local climate for the human population.In this process local birch populations that are adapted to a more coastal climate,would have an advantage.Since birch has been shown to be an important resource for all these cultures,this would decrease the level of conflicts between the different groups of stakeholders about the resources in the area.

Effects of indole-3-butyric acid and age of stem cuttings on root morphology,growth,and survival of Cornus sericea

Red osier dogwood(Cornus sericea L.),widely distributed throughout North America,is essential for wildlife,thus biodiversity.It is recommended for reclamation or revegetation of sites disturbed by oil and gas extraction because it tolerates a wide range of soil types and high pH levels.Since germination of this species is extremely difficult with long stratification requirements and poor germination,cuttings facilitate propagation.In this study,to develop techniques to propagate the species from stem cuttings,four concentrations of indole-3-butyric acid(IBA)and two cutting ages previous year’s growth(PYG)and current year’s growth(CYG)were investigated for survival and growth.After 4 months,survival rate,height growth,and shoot biomass from PYG cuttings were enhanced with IB A.In contrast,IB A did not affect these parameters in CYG cuttings.Root morphology was significantly affected by IB A concentration and cutting age.IBA,at higher concentrations,increased root surface and length.Total root surface area and length of PYG cuttings were increased,which may facilitate the absorption of essential resources and consequently increase growth.The results indicate that increasing the concentration of IB A may be an effective way to have better plant survival and growth of previous year’s cuttings in red osier dogwood.

基于两种半分析算法的水体吸收系数反演

基于42组不同年份不同季节获得的遥感反射率、水体各组分吸收系数的实测数据,对QAA(Quasi-Analytical Algorithm)和GSM(Garver-Siegel-Maritorena)算法在寡营养的南海和富营养的福建沿岸两种不同类型水体的吸收系数反演进行了检验。以水样测量值为参考,两种算法在本研究水体中的反演成效与他人在其它水域的研究结果相当。QAA算法在南海的反演成效高于福建沿岸水体。对于443nm的总吸收系数a(443),南海的对数均方根误差RMSE为0.044,平均相对误差ε为7.9%,对数平均偏差δ为0;福建沿岸水体RMSE=0.190,ε=30.6%,δ=-0.167。GSM算法在两类水体的反演成效类似,a(443)之RMSE和ε,南海分别为0.156和27.7%,福建沿岸分别为0.146和32.1%;但从a(443)的δ值看,其在南海反演值低于实测值(δ=-0.142),在福建沿岸则略呈高于实测值(δ=0.016)。两种算法中的部分经验参数与实测值之间的差异是产生反演误差的主要原因,为了提高反演精度,对算法中经验参数的更进一步区域化调整可能是必要的。

基于固有光学特性的北部湾透明度遥感反演及其检验

综合了固有光学量的反演和透明度与固有光学量的关系,构成了基于固有光学特性的透明度遥感算法。将此算法应用于北部湾的MODIS遥感数据,得到了该区域的透明度,并利用实测透明度对遥感反演结果进行了验证。通过对时间窗口为±48h,空间窗口为1km的30组实测与遥感匹配数据的统计分析(实测透明度在1.8～26.0m范围),得到平均百分比误差(ε)为22%,对数均方根误差(1og_RMSE)为0.121。而基于叶绿素的经验算法反演的透明度,ε为42%,log_RMSE为0.185。上述结果说明,至少对于北部湾这类近岸水体,海色遥感结合基于固有光学量的算法,可以实现较高准确度的透明度遥感反演。

抗氧化剂对表皮通透屏障功能的影响

表皮通透屏障功能对皮肤功能具有重要调节作用。增强表皮通透屏障功能已成为防治某些皮肤病和延缓皮肤老化的手段之一。研究显示,抗氧化剂可通过促进表皮细胞分化及其脂的合成而增强表皮透屏障功能。由此提示,抗氧化剂可用于防治某些皮肤病和延缓皮肤老化。

评估表皮通透屏障功能的方法及其应用

表皮通透屏障功能是指表皮防止物质通过表皮进出机体的功能。该功能对于表皮的增生分化、炎症的形成与发展以及抗微生物感染等方面都具有重要作用。而表皮通透屏障功能受体内外多种生物、物理因素的影响。因此,调节表皮通透屏障功能是皮肤保健和防治某些皮肤病的重要手段;评估表皮通透屏障功能是了解皮肤生物功能以及判断皮肤保健、治疗效果的方法。评估表皮通透屏障功能的方法很多。除测量透皮失水率外,超微示踪、透皮微量分析、同位素及荧光标记定位和定量等都是评估表皮通透屏障功能的有效方法。了解这些方法的特点对于选择恰当的手段和有效地评估表皮通透屏障功能具有重要的指导意义。

俄罗斯沙棘引种繁育研究综述

俄罗斯已经有250名科学家进行了俄罗斯联邦沙棘本身具有的自然资源、沙棘生态学、植物学和形态学;基因和遗传学;生物化学;可种植环境延伸研究。160年前的苏联,沙棘最初是作为一种绿化美化的植物种植。野生沙棘的产量低,并且沙棘的生物化学组分分布也不均匀,同时由于具有棘刺,果实的收获方式也不同,因此,发展果园种植的模式很重要。俄罗斯的植物繁育者坚持不懈的收集并研究沙棘的基因组成,同时不断改良使沙棘繁育的方式更加有效。在下面的文章中我们将讨论一些沙棘繁育的方法。

叶绿素浓度垂直不均一分布对于分层水体表观光学特性的影响

以往大部分海洋光学和海色研究都是以海洋光学有效成分及固有光学特性垂直均一分布的假设为基础进行的,然而海洋观测表明海水成分的垂直不均一性大量存在。文章通过Hydrolight辐射传输模拟研究了叶绿素浓度垂直不均一分布对海水表观光学特性的影响。叶绿素浓度垂直不均一分布由高斯模型来近似模拟,选择成熟的一类水体生物光学模型,利用Hydrolight辐射传输代码模拟表观光学特性,将垂直不均一廓线情况下模拟的表观光学特性值与具有本底值的均一廓线情况所模拟的相应值进行了比较。结果表明,水表面以下的叶绿素浓度最大值增加了蓝光波段的遥感反射率,减小了绿光波段的遥感反射率,而且改变了水体中辐射的方向分布,在叶绿素浓度最大值处,下行辐射漫衰减系数和平均余弦廓线分别出现峰值和谷值。

Using induced pluripotent stem cells as a tool for modelling carcinogenesis

Cancer is a highly heterogeneous group of diseases that despite improved treatments remain prevalent accounting for over 14 million new cases and 8.2 million deaths per year. Studies into the process of carcinogenesis are limited by lack of appropriate models for the development and pathogenesis of the disease based on human tissues. Primary culture of patient samples can help but is difficult to grow for a number of tissues. A potential opportunity to overcome these barriers is based on the landmark study by Yamanaka which demonstrated the ability of four factors;Oct4, Sox2, Klf4, and c-Myc to reprogram human somatic cells in to pluripotency. These cells were termed induced pluripotent stem cells(i PSCs) and display characteristic properties of embryonic stem cells. This technique has a wide range of potential uses including disease modelling, drug testing and transplantation studies. Interestingly i PSCs also share a number of characteristics with cancer cells including self-renewal and proliferation, expression of stem cell markers and altered metabolism. Recently, i PSCs have been generated from a number of human cancer cell lines and primary tumour samples from a range of cancers in an attempt to recapitulate the development of cancer and interrogate the underlying mechanisms involved. This review will outline the similarities between the reprogramming process and carcinogenesis, and how these similarities have been exploited to generate i PSC models for a number of cancers.

Protective effect and mechanism of lithium chloride pretreatment on myocardial ischemia-reperfusion injury in rats

Objective:To investigate the protective effect and mechanism of lithium chloride pretreatment on myocardial ischemia-reperfusion injury(I-RI)in rats.Methods:A total of 60 SD rats were randomly divided into control group,model group,lithium chloride intervention group and L-arginine methyl ester+lithium chloride intervention group with 15 in each.The I-RI model was established in model group,the Utliium chloride intervention group and L-arginine methyl ester+lithium chloride intervention group by method of seaming along left anterior descending coronary artery myocardial,control group was only opened the chest without seaming,STelevation within 2 min was regarded as modeling success.Model group did not adopted any intervention,lithium chloride intervention group was treated with lithium chloride injection15 mg/kg by jugular venipuncture preoperatively,L-arginine methyl ester+lithium chloride intervention group was treated with intraperitoneal injection of 30mg·kg～(-1)·d～(-1)(L—arginine methyl ester 7 d before the test,and intravenous catheter of 15 mg/kg lithium chloride preoperatively.The hydroxybulyric acid dehydrogenase(HBDH),creatine kinase isoenzyme(CK-MB),superoxide dismutase(SOD),malondialdehyde(MDA)level and nitric oxide synthase(NOS)activites were tested.Each large area of myocardial ischemia tissue was extracted for determination of the MDA content,SOD activity in tissue and serum,and morphological changes of myocardial tissue.Results:SOD activity was highest in lithium chloride intervention group,followed by L-arginine methyl ester+lithium chloride intervention group,control group and model group(P<0.05);SOD activity was highest in L-arginine methyl ester+lithium chloride intervention group intervention group,followed by lithium chloride intervention group,control group and model group(P<0.05).MDA content of myocardial tissue was highest in model group,followed by L-arginine methyl ester+lithium chloride intervention group,the lithium chloride intervention group and control group(P<0.05);serum MDA content was highest in L-arginine methyl ester+lithium chloride intervention group,followed by model group,lithium chloride intervention group and control group(P<0.05).Compared with the control group,serum NOS was significantly higher in model group,lithium chloride intervention group and L-arginine methyl ester+lithium chloride intervention group(P<0.05),there was no statistical difference of serum NOS activity between the three groups(P>0.05);HBDH and CK-MB of plasma were highest in model group,followed by L-arginine methyl ester+lithium chloride intervention group,lithium chloride intervention group and control group(P<0.05).A significantly lighter myocardial damage was observed microscopically in lithium chloride intervention group than that in L-arginine methyl ester+lithium chloride intervention group and model group.Conclusions:lithium chloride pretreatment can significandy reduce the myocardial I-RI,maintain structure and function of myocardial cells,improve the antioxidant ability of myocardial tissue,play an effective role on protecting myocardial I-RI.

Intestinal microflora molecular markers of spleen-deficient rats and evaluation of traditional Chinese drugs

AIM:To find a rapid and efficient analysis method of gastrointestinal microflora in Pi-deficient(spleen-deficient) rats and to evaluate traditional Chinese drugs.METHODS:Enterobacterial repetitive intergenic consensus-PCR(ERIC-PCR) based assay was performed to examine changes of intestinal microflora in two Pi-deficienct animal models and to evaluate the efficacy of four traditional Chinese drugs as well as a probiotic recipe and another therapy in Pi-deficient rats.RESULTS:A molecular marker was identified for Pi-deficiency in rats.The pharmacodynamic evaluation system,including identified molecular markers(net integral area and abundance of DNA bands),Shannon's index for diversity of intestinal microflora,and Sorenson's pairwise similarity coefficient,was established.The four major clinical recipes of traditional Chinese drugs for Pi-deficiency in rats,especially at their medium dose(equivalence to the clinical dose),produced more pronounced recovery activities in Pi-deficient rats,while higher doses of these recipes did not show a better therapeutic effect but some toxic effects such as perturbation deterioration of intestinal microflora.CONCLUSION:Both fingerprint analysis and identified marker can show Pi-deficiency in rats and its difference after treatment.The identified molecular marker may be applied in screening for the active compounds both in relative traditional Chinese drugs and in pharmacodynamic study of Pi-deficiency in rats.

How can social enterprises contribute to sustainable pro-poor tourism development?

"Tourism-Assisting the Poor" has been an important approach in anti-poverty strategy. Studies suggest that the conventional tourism model fails to generate benefits for the poor and to some extent enlarges the gap between the poor and the rich, which subsequently causes more social problems. Pro-poor tourism(PPT) is regarded as an alternative model. Precisely targeted assistance to the poor is the key to initiating this model, while the institutional change and implementation mechanism are essential to run it successfully and sustainably. Social entrepreneurship focusing on social values while adopting modern business philosophy has been introduced recently as an instrument in helping disadvantage population. This paper takes the Smangus community in Taiwan as an example to explore the role of social entrepreneurship and social enterprises in PPT development. It also discusses their implications for the anti-poverty practice in other regions including ethnic areas in China.

老年人表皮通透屏障功能的改变及其临床意义

表皮通透屏障是机体抵御外界有害物质侵入和阻止体内物质丢失的一道重要屏障。随着机体衰老,表皮角质形成细胞增生分化能力降低、脂质合成减少,而表皮pH升高,最终导致表皮通透屏障功能恢复速度减慢。表皮通透屏障功能的降低,不仅加快皮肤和血液中炎症因子的增多,还会增大皮肤感染风险。皮肤炎症因子持续表达增高可引起慢性皮肤瘙痒等,同时可诱发和加重系统性炎症,参与多种系统性疾病的发生与发展。因此,改善老年表皮通透屏障功能将可能成为预防和治疗某些老年疾病的有效方法之一。

A method of line spectrum extraction based on target radiated spectrum feature and its post-processing

To improve the ability of detecting underwater targets under strong wideband interference environment,an efficient method of line spectrum extraction is proposed,which fully utilizes the feature of the target spectrum that the high intense and stable line spectrum is superimposed on the wide continuous spectrum.This method modifies the traditional beam forming algorithm by calculating and fusing the beam forming results at multi-frequency band and multi-azimuth interval,showing an excellent way to extract the line spectrum when the interference and the target are not in the same azimuth interval simultaneously.Statistical efficiency of the estimated azimuth variance and corresponding power of the line spectrum band depends on the line spectra ratio(LSR)of the line spectrum.The change laws of the output signal to noise ratio(SNR)with the LSR,the input SNR,the integration time and the filtering bandwidth of different algorithms bring the selection principle of the critical LSR.As the basis,the detection gain of wideband energy integration and the narrowband line spectrum algorithm are theoretically analyzed.The simulation detection gain demonstrates a good match with the theoretical model.The application conditions of all methods are verified by the receiver operating characteristic(ROC)curve and experimental data from Qiandao Lake.In fact,combining the two methods for target detection reduces the missed detection rate.The proposed post-processing method in2-dimension with the Kalman filter in the time dimension and the background equalization algorithm in the azimuth dimension makes use of the strong correlation between adjacent frames,could further remove background fluctuation and improve the display effect.

Oracle智能化内存管理特性与配置方法

Oracle数据库的内存管理具有智能化的特点,可根据具体工作负载进行调配。通过对校企合作实训实验总结,按照工作任务的不同直接设置内存管理方式和参数,以及按照内存监测再调整参数的等方法,概括多种内存管理方式以及各种参数的设置,并给出重要的提示,以便尽快提高Oracle系统性能。

Raman Frequency Conversion of Picosecond Pulses in the YVO4 Crystal

We compare the stimulated Raman scattering(SRS)performance of a-cut and c-cut YVO4 in a single-pass Raman experiment.The undoped YVO4 crystal shows its good SRS capability in a quasi-transient field.The non-axial scattering angles of Raman radiation are also studied,and the result is in good agreement with the physical model based on the phase matching condition.High-order Raman Stokes and anti-Stokes lights with good beam quality are obtained by means of Raman amplification.Our experiments show that Raman amplification is a practical way to avoid unexpected nonlinear effects and to obtain new wavelength picosecond lasers.

Study on the forecasting and maintenance system of special railway subsidence in mine area

The fully mechanized caving coal mining under the railway in mine area will result in difficulty maintenance of railway because of great distortion and subsidence speed of terrene and railway. If the subsidence forecasting is incorrect and maintenance measure is not suitable in the preceding and the process of mining, the normal operation of the railway in mine area will not be ensured and perhaps the safety accident will be resulted. The railway subsidence forecasting and maintenance system for fully mechanized caving coal face are studied and developed in this connection. Based on the accurate subsidence forecasting of the terrene and railway, the maintenance measure for track and switch turnout in railway is put forward in this system.

EQUIVALENT BOUNDARY INTEGRAL EQUATIONS WITH INDIRECT VARIABLES FOR PLANE ELASTICITY PROBLEMS

The exact form of the exterior problem for plane elasticity problems was produced and fully proved by the variational principle.Based on this,the equivalent boundary integral equations(EBIE) with direct variables,which are equivalent to the original boundary value problem,were deduced rigorously.The conventionally prevailing boundary integral equation with direct variables was discussed thoroughly by some examples and it is shown that the previous results are not EBIE.