Detection of a direct carbon dioxide effect in continental river runoff records

Continental runoff has increased through the twentieth century despite more intensive human water consumption. Possible reasons for the increase include: climate change and variability, deforestation, solar dimming, and direct atmospheric carbon dioxide (CO2) effects on plant transpiration. All of these mechanisms have the potential to affect precipitation and/or evaporation and thereby modify runoff. Here we use a mechanistic land-surface model and optimal fingerprinting statistical techniques to attribute observational runoff changes into contributions due to these factors. The model successfully captures the climate-driven inter-annual runoff variability, but twentieth-century climate alone is insufficient to explain the runoff trends. Instead we find that the trends are consistent with a suppression of plant transpiration due to CO2-induced stomatal closure. This result will affect projections of freshwater availability, and also represents the detection of a direct CO2 effect on the functioning of the terrestrial biosphere.     

Corneal avascularity is due to soluble VEGF receptor-1

Corneal avascularity-the absence of blood vessels in the cornea-is required for optical clarity and optimal vision, and has led to the cornea being widely used for validating pro- and anti-angiogenic therapeutic strategies for many disorders. But the molecular underpinnings of the avascular phenotype have until now remained obscure and are all the more remarkable given the presence in the cornea of vascular endothelial growth factor (VEGF)-A, a potent stimulator of angiogenesis, and the proximity of the cornea to vascularized tissues. Here we show that the cornea expresses soluble VEGF receptor-1 (sVEGFR-1; also known as sflt-1) and that suppression of this endogenous VEGF-A trap by neutralizing antibodies, RNA interference or Cre-lox-mediated gene disruption abolishes corneal avascularity in mice. The spontaneously vascularized corneas of corn1 and Pax6+/- mice and Pax6+/- patients with aniridia are deficient in sflt-1, and recombinant sflt-1 administration restores corneal avascularity in corn1 and Pax6+/- mice. Manatees, the only known creatures uniformly to have vascularized corneas, do not express sflt-1, whereas the avascular corneas of dugongs, also members of the order Sirenia, elephants, the closest extant terrestrial phylogenetic relatives of manatees, and other marine mammals (dolphins and whales) contain sflt-1, indicating that it has a crucial, evolutionarily conserved role. The recognition that sflt-1 is essential for preserving the avascular ambit of the cornea can rationally guide its use as a platform for angiogenic modulators, supports its use in treating neovascular diseases, and might provide insight into the immunological privilege of the cornea.     

基于稀疏表示的平行互素阵二维测向方法

针对传统平行阵二维测向自由度低问题,提出一种改进型平行互素阵,基于稀疏表示方法和最小二乘法来估计目标方位。该方法首先利用改进型互素阵构建双平行稀疏阵列,计算平行互素阵的互协方差矩阵。然后通过矢量化处理,利用重排,去冗余处理生成较大孔径的虚拟阵列,将二维波达方向(direction of arrival,DOA)估计问题降维为一维DOA估计问题。进一步将一维DOA估计问题转为复数信号稀疏重构问题,并利用二阶锥规划来进行求解,通过峰值搜索得到方位角信息。最后利用方位角来构建方向矩阵,通过最小二乘方法求解俯仰角。该方法可以在没有目标先验信息的条件下,能够准确估计目标方位,且能够实现自动配对。相比传统的平行均匀线阵以及平行互素阵,该方法扩展了阵列虚拟孔径,提高了估计精度,能够辨识更多的目标源。实验仿真验证了该方法的有效性。     

A New Adaptive Formant Vocoder

A new type of vocoder system based upon formant analysis is presented in this paper. The LMS adaptive algorithm is used for tracking formants of speech signals. The results of computer simulation show that the new vocoder has better synthesized speech quality.     

男旦乐伎对清代中前期文学的影响

清代中前期是伎乐转型的关键期,男旦成为公共乐伎的主导力量。这一转变使得男旦对文人生态和各种体裁的文学作品产生了深刻影响。     

Laccases of prokaryotic origin: enzymes at the interface of protein science and protein technology

The ubiquitous members of the multicopper oxidase family of enzymes oxidize a range of aromatic substrates such as polyphenols, methoxy-substituted phenols, amines and inorganic compounds, concomitantly with the reduction of molecular dioxygen to water. This family of enzymes can be broadly divided into two functional classes: metalloxidases and laccases. Several prokaryotic metalloxidases have been described in the last decade showing a robust activity towards metals, such as Cu(I), Fe(II) or Mn(II) and have been implicated in the metal metabolism of the corresponding microorganisms. Many laccases, with a superior efficiency for oxidation of organic compounds when compared with metals, have also been identified and characterized from prokaryotes, playing roles that more closely conform to those of intermediary metabolism. This review aims to present an update of current knowledge on prokaryotic multicopper oxidases, with a special emphasis on laccases, anticipating their enormous potential for industrial and environmental applications.     

Permissible idealizations for the purpose of prediction

Every model leaves out or distorts some factors that are causally connected to its target phenomenon—the phenomenon that it seeks to predict or explain. If we want to make predictions, and we want to base decisions on those predictions, what is it safe to omit or to simplify, and what ought a causal model to describe fully and correctly? A schematic answer: the factors that matter are those that make a difference to the target phenomenon. There are several ways to understand differencemaking. This paper advances a view as to which is the most relevant to the forecaster and the decision-maker. It turns out that the right notion of differencemaking for thinking about idealization in prediction is also the right notion for thinking about idealization in explanation; this suggests a carefully circumscribed version of Hempel’s famous thesis that there is a symmetry between explanation and prediction.     

新疆高校体育教师工作压力状况调查研究

采用文献资料法、问卷调查法对新疆维吾尔自治区228名高校民汉体育教师的工作压力状况进行了调查,以期为预防和缓解新疆高校体育教师工作压力提供一定的理论依据,并希望以此引起各相关部门对高校体育教师工作压力问题的广泛关注,采取有力措施,切实减轻高校体育教师的工作压力.运用SPSS 16.0软件对收集的数据进行独立样本T检验、One-way ANOVA和Cross-tabs分析.结果显示:高校体育教师工作压力较大,在工作中感受到来自科研、职业期望及自我发展的压力,同时还感受到相当程度的来自工作因素、组织氛围及学生因素的压力,新疆高校体育教师在族别、职称、学历、年龄和教龄5个方面工作压力都存在显著差异.