Robust functional estimation using the median and spherical principal components

We present robust estimators for the mean and the principalcomponents of a stochastic process in . Robustness and asymptotic properties of theestimators are studied theoretically, by simulation and by example.It is shown that the proposed estimators are generally morerobust to outliers than the commonly used sample mean and principalcomponents, although their properties depend on the spacingsof the eigenvalues of the covariance function.     

一类具稀疏效应生态系统的极限环

研究如下一类具稀疏效应的生态系统模型dx/dt=bx^2(κ-x)-bxy/1 hx,dy/dt=cy dxy/1 hx。应用微分方程定性理论,对该系统的平衡点进行了分析,给出了极限环存在唯一性及不存在的参数范围。     

带超前项的二阶脉冲中立型积分微分方程解的存在性(英文)

应用不动点定理,研究了带超前项的二阶脉冲中立型积分微分方程解的存在性,建立了两个存在准则,并举例说明了准则的有效性.     

日立835─50型氨基酸分析仪故障排除六例

给出日立８３５－５０型氨基酸分析仪使用过程中出现的六种故障现象及判断排除方法     

日立835─50型氨基酸分析仪故障排除六例

给出日立８３５－５０型氨基酸分析仪使用过程中出现的六种故障现象及判断排除方法     

Collagen fibril diameters increase and fibril densities decrease in skin subjected to repetitive compressive and shear stresses

Understanding microstructural changes that occur in skin subjected to repetitive mechanical stress is crucial towards the development of therapies to enhance skin adaptation and load tolerance in patients at risk of skin breakdown (e.g. prosthesis users, wheelchair users). To determine if collagen fibril diameter, collagen fibril density, dermal thickness, epidermal thickness, basement membrane length, and dermal cell density changed in response to repetitive stress application, skin subjected to moderate cyclic compressive and shear stresses for 1 h/d, 5 d/week, for 4 week was compared with skin from an unstressed contralateral control. The lateral aspects of the hind limbs of 12 Landrace/Yorkshire pigs were used. Skin from under the stressed site and a contralateral control site was processed for electron microscopy and light microscopy analysis. Electron microscopy results demonstrated significant (p<0.01) increases in collagen fibril diameter of 15.9%, 22.4%, and 22.9% for the upper, mid, and lower layers of the dermis, respectively, for the stressed skin compared with the control skin. Collagen fibril density (fibrils/unit cross-sectional area) decreased significantly for stressed vs. control by 19.8%, 29.2%, and 31.8% for the upper, mid, and lower layers, respectively. Light microscopy results demonstrated trends of a decrease in dermal thickness and an increase in cell density for stressed vs. control samples, but the differences were not significant. Differences in epidermal thickness and basement membrane length were not significant. These results demonstrate that quantifiable changes occur in collagen fibril architecture but not in the gross tissue morphology following in vivo cyclic loading of pig skin.     

Population genomics: a new generation of genome scans to bridge the gap with functional genomics

Population genomics is an increasingly popular approach to investigate the genetic basis of adaptation and speciation at the genome scale. However, it has so far largely failed to go beyond the mere identification of anonymous markers displaying selection signatures. Will population genomics ever be up to our expectations and able to really pinpoint genes underlying adaptation and speciation processes? In this issue of Molecular Ecology, Namroud et al. use population genomics to investigate local adaptation in natural populations of a conifer tree, the white spruce (Picea glauca). They show how population and functional genomics can finally converge with the deployment of the next generation of genome scans, which target gene‐rich regions rather than the whole genome.