浅析市场经济条件下水资源管理的三大转变

在市场经济条件下，水资源管理要实现三大转变：一是由传统防范和利用意识向市场资源型转变，建立起水的资源观、可持续利用观和价值观；二是由行政管水的运行机制向水市场体系转变，逐步建立起市场调节与政府调控相结合的新的管理机制；三是由政出多门的管理体制向水务一体化管理体制转变，建立起“统一、高效、负责”的水务一体化管理体制。     

Evolution of cooperation in a finite homogeneous graph

Recent theoretical studies of selection in finite structured populations have worked with one of two measures of selective advantage of an allele: fixation probability and inclusive fitness. Each approach has its own analytical strengths, but given certain assumptions they provide equivalent results. In most instances the structure of the population can be specified by a network of nodes connected by edges (that is, a graph), and much of the work here has focused on a continuous-time model of evolution, first described by ref. 11. Working in this context, we provide an inclusive fitness analysis to derive a surprisingly simple analytical condition for the selective advantage of a cooperative allele in any graph for which the structure satisfies a general symmetry condition ('bi-transitivity'). Our results hold for a broad class of population structures, including most of those analysed previously, as well as some for which a direct calculation of fixation probability has appeared intractable. Notably, under some forms of population regulation, the ability of a cooperative allele to invade is seen to be independent of the nature of population structure (and in particular of how game partnerships are specified) and is identical to that for an unstructured population. For other types of population regulation our results reveal that cooperation can invade if players choose partners along relatively 'high-weight' edges.     

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

Blood pressure is a heritable trait influenced by several biological pathways and responsive to environmental stimuli. Over one billion people worldwide have hypertension (≥140?mm?Hg systolic blood pressure or ≥90?mm?Hg diastolic blood pressure). Even small increments in blood pressure are associated with an increased risk of cardiovascular events. This genome-wide association study of systolic and diastolic blood pressure, which used a multi-stage design in 200,000 individuals of European descent, identified sixteen novel loci: six of these loci contain genes previously known or suspected to regulate blood pressure (GUCY1A3-GUCY1B3, NPR3-C5orf23, ADM, FURIN-FES, GOSR2, GNAS-EDN3); the other ten provide new clues to blood pressure physiology. A genetic risk score based on 29 genome-wide significant variants was associated with hypertension, left ventricular wall thickness, stroke and coronary artery disease, but not kidney disease or kidney function. We also observed associations with blood pressure in East Asian, South Asian and African ancestry individuals. Our findings provide new insights into the genetics and biology of blood pressure, and suggest potential novel therapeutic pathways for cardiovascular disease prevention.     

核能谱与两类转动惯量的精确表达式

用最小二乘拟合法,将稀土区的能谱实验数据,拟合不同的能谱公式,从而证明E=a〔(1+bI(I+1))~(1/2)-1〕是符合得较好的,本文还推导了与上述能谱相应的两类转动惯量,并以此与实验计算值进行比较,结果仍很满意.     

Coral mucus functions as an energy carrier and particle trap in the reef ecosystem

Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs, but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus. Here we show that released coral mucus efficiently traps organic matter from the water column and rapidly carries energy and nutrients to the reef lagoon sediment, which acts as a biocatalytic mineralizing filter. In the Great Barrier Reef, the dominant genus of hard corals, Acropora, exudes up to 4.8 litres of mucus per square metre of reef area per day. Between 56% and 80% of this mucus dissolves in the reef water, which is filtered through the lagoon sands. Here, coral mucus is degraded at a turnover rate of at least 7% per hour. Detached undissolved mucus traps suspended particles, increasing its initial organic carbon and nitrogen content by three orders of magnitude within 2 h. Tidal currents concentrate these mucus aggregates into the lagoon, where they rapidly settle. Coral mucus provides light energy harvested by the zooxanthellae and trapped particles to the heterotrophic reef community, thereby establishing a recycling loop that supports benthic life, while reducing loss of energy and nutrients from the reef ecosystem.     

SLC2A9 is a newly identified urate transporter influencing serum urate concentration, urate excretion and gout

Uric acid is the end product of purine metabolism in humans and great apes, which have lost hepatic uricase activity, leading to uniquely high serum uric acid concentrations (200-500 microM) compared with other mammals (3-120 microM). About 70% of daily urate disposal occurs via the kidneys, and in 5-25% of the human population, impaired renal excretion leads to hyperuricemia. About 10% of people with hyperuricemia develop gout, an inflammatory arthritis that results from deposition of monosodium urate crystals in the joint. We have identified genetic variants within a transporter gene, SLC2A9, that explain 1.7-5.3% of the variance in serum uric acid concentrations, following a genome-wide association scan in a Croatian population sample. SLC2A9 variants were also associated with low fractional excretion of uric acid and/or gout in UK, Croatian and German population samples. SLC2A9 is a known fructose transporter, and we now show that it has strong uric acid transport activity in Xenopus laevis oocytes.     

一种改进的规划器算法在军用软件GUI测试用例自动生成中的应用

以人工智能中智能规划方法为基础,对军用软件测试用例自动生成技术进行了研究。现有的许多规划器都不能避免组合爆炸问题的发生,而这一问题又是导致规划失败的一个重要问题,针对这一现象,以IPP规划器为例,提出目标分解法对规划器所需事实文件进行划分,并对IPP规划器应用多事实文件处理算法进行扩展,扩展后的MF-IPP规划器能够处理多个事实文档,有效避免了组合爆炸问题的发生。将该方法应用到军用主控软件GUI(Graphical User Interface)测试用例自动生成中,主要思想是首先利用规划器生成初始测试用例,其次提出解扩展的方法来完善测试用例的生成。针对测试用例生成问题进行了比对分析,结果显示,MF-IPP可以很好地防止组合爆炸问题的发生。所生成的测试用例生成时间短、覆盖率高,不仅能够很好地辅助软件测试人员进行测试用例的编写,还能应用于自动化软件测试。     

Crystallographic studies on the activity of glycogen phosphorylase b

High resolution studies on the crystal structure of glycogen phosphorylase b have identified the catalytic site to which the substrate glucose-1-phosphate binds strongly with some local conformational changes. The site is situated 8 A (phosphate-to-phosphate distance) from pyridoxal phosphate, an essential cofactor of all glycogen phosphorylases. The catalytic site is 33 A from the site in the N-terminal portion of the molecule to which adenine nucleotides bind. In contrast to phosphorylase a (the active form of the enzyme which is phosphorylated at Ser 14), the positions of the first 19 residues of phosphorylase b are not well defined.