Double seismic zone for deep earthquakes in the izu-bonin subduction zone

A double seismic zone for deep earthquakes was found in the Izu-Bonin region. An analysis of SP-converted phases confirms that the deep seismic zone consists of two layers separated by approximately 20 kilometers. Numerical modeling of the thermal structure implies that the hypocenters are located along isotherms of 500 degrees to 550 degrees C, which is consistent with the hypothesis that deep earthquakes result from the phase transition of metastable olivine to a high-pressure phase in the subducting slab.     

Ionic mechanisms controlling behavioral responses of paramecium to mechanical stimulation

A mechanical stimulus applied to the anterior part of Paramecium causes a transient increase in membrane permeability to calcium. This permits a calcium current to flow into the cell, causing the membrane potential to approach the equilibrium level for calcium. The transient depolarization which results elicits a reversal in the direction of ciliary beat. When the organisms are free-swimming this is seen as the reversed locomotion of Jennings' "avoiding reaction." In contrast, a mechanical stimulus applied to the posterior part results in increased permeability to potassium ions, and hence an outward potassium current. The hyperpolarization which results causes an increase in the frequency of ciliary beat in the normal direction. In free-swimming specimens this is seen as an increase in the velocity of forward locomotion.     

宋代農田水利的開發

宋代興修農田水利主要方面可分為四大項:一、利用河北淀泊開闢稻田,二、利用東南窪地修築圩田,三、引濁放淤,改良鹽鹼土地,四、修復古渠舊堰,以利灌溉。這些都是具有一定的基礎和原因,也都在農業生產上獲得成績,因而促進了經濟的發展。現在我們正在執行發展國民經濟的第一個五年計劃,其中有"積極興修農田水利"的規定。古人說"温故而知新",為由歷史上找出發展的道路起見,特寫此短篇,聊供設計時的參考。     

The impact of boreal forest fire on climate warming

We report measurements and analysis of a boreal forest fire, integrating the effects of greenhouse gases, aerosols, black carbon deposition on snow and sea ice, and postfire changes in surface albedo. The net effect of all agents was to increase radiative forcing during the first year (34 +/- 31 Watts per square meter of burned area), but to decrease radiative forcing when averaged over an 80-year fire cycle (-2.3 +/- 2.2 Watts per square meter) because multidecadal increases in surface albedo had a larger impact than fire-emitted greenhouse gases. This result implies that future increases in boreal fire may not accelerate climate warming.     

收割机前部扩充配件对降低油菜收获损失的作用（摘选）

如今,伊朗油菜种植已经在其国内各地发展起来。然而,在整地、种植和收获过程中仍然存在一些问题。因此,需要采用新技术进行机械化收获。目前,谷物联合收获机生产公司除了生产常用设备,也生产一些安装在割台上的扩充配件。机械化收获系统尤其是常用的收获割台存在有相当大的损耗,同时熟练程度和需要特殊的油菜收获配套设备也是造成损失的原因之一。该试验研究一种割台和两种割台扩充配件对油菜收获损失的影响,从而确定损失量以及造成损失的原因。试验中涉及到一种常见割台,以及伊朗制造的采用机械侧刀切割器的Hamed割台扩充配件和采用液压侧刀切割器的Bizo割台扩充配件。试验采用随机完全区组设计,设6次重复。利用安置的托盘测定收获损失量。结果表明,随着割台运禾螺杆与切割器间距离的加大,割台扩充配件能降低损失量。因此,从总损失量考虑,常用割台与其他两种扩充配件相比差异显著。普通割台损失量为599 kghm2,而采用侧面垂直切割可以减少71 kghm2。此外,使用液压系统替代机械系统以及使用双层切割器替代单层刀杆都有助于降低损失量。试验结果显示,破损种子量为39.6 kghm2,占总产量的1.12%。试验结果是令人满意的,同时改善了联合收获机的性能。通过使用割台扩充配件有利于降低收获中的损耗。      

Evapotranspiration and crop coefficient of Populus euphratica Oliv forest during the growing season in the extreme arid region northwest China

Based on successive observation, fifteen-day evapotranspiration (ET_c) of Populus euphratica Oliv forest, in the extreme arid region northwest China, was estimated by application of Bowen ratio-energy balance method (BREB) during the growing season in 2005. During the growing season in 2005, total ET_c was 446.96 mm. From the beginning of growing season, the ET_c increased gradually, and reached its maximum value of 6.724 mm d⁻¹ in the last fifteen days of June. Hereafter the ET_c dropped rapidly, and reached its minimum value of 1.215 mm d⁻¹ at the end of growing season. The variation pattern of crop coefficient (K_c) was similar to that of ET_c. From the beginning of growing season, the K_c value increased rapidly, and reached its maximum value of 0.623 in the last fifteen days of June. Afterward, with slowing growth of P. euphratica, the value dropped rapidly to the end of growing season. According to this study, the ET_c of P. euphratica forest is affected not only by meteorological factors, but by water content in soil.     

Mapping QTLs for Yield Stability in Durum Wheat Grown under Different Water Regimes

Among the most important Mediterranean annual crops, durum wheat is widely grown in drought-prone areas. Therefore, improving water-use efficiency （WUE） of durum wheat represents a major breeding goal. IDu-WUE （Improving Durum wheat for Water Use Efficiency and yield stability through physiological and molecular approaches） is a collaborative project among public and private research centres in Italy, Spain and WANA （West Asia and North Africa） countries （Morocco, Tunisia, Syria and Lebanon） funded by the European Union aimed at investigating the genetic variation for WUE and yield stability in durum wheat grown in Mediterranean droughtprone areas. During the first year of the project, a number of morpho-physiological traits （e.g. early vigour, flowering time, leaf rolling, number of fertile tillers, etc.）, WUE, WUE-related traits （e.g. carbon isotope discrimination, canopy temperature, chlorophyll fluorescence, etc.）, yield and its components have been investigated in a RIL population （249 lines） and a collection of ca. 190 durum wheat accessions characterized by a high level of linkage disequilibrium （Maccaferri et al., 2005）,     

Genetic Diversity of Peanut Core Collection from US Using Simple Sequence Repeats

Groundnut is a member of genus Arachis and the crop is divided into two subspecies and six botanical varieties based on morphological characteristics （Krapovickas and Gregory, 1994）. The International Crops Research Institute for the Semi-Arid Tropics （ICRISAT） holds more than 14 000 groundnut accessions from which a core collection of 1 704 have been developed （Upadhyaya et al., 2003）. Holdbrook et al. （1993） developed a groundnut core collection of 831 accessions from a total of 7 432 US groundnut accessions based on morphological characteristics. The large number and variability of accessions in GenBanks create problems in knowing which germplasm to select for breeding purpose. Only a few established cultivars and elite breeding lines have been utilised in breeding programmes. A core collection is a fraction of accessions from the entire collection which represent most of the available genetic diversity of the species. A core collection can extensively be evaluated and information derived from them can be applied to the whole collection. Identification of DNA markers associated with the botanical varieties of groundnut would be useful in genotyping, germplasm management and evolutionary studies.     

Differentiation of the high molecular weight glutenin subunit D t x 2.1 of Aegilops tauschii indicated by partial sequences of its encoding gene and SSR markers

The devastating late blight pathogen Phytophthora infestans infects foliage as well as tubers of potato. To date, resistance breeding has often focused on foliage blight resistance, but tuber blight resistance is becoming more and more important in cultivated potatoes. In this study, a reliable tuber assay for resistance assessment was developed and foliage and tuber blight resistance (R) was compared in four mapping populations. In the RH4X-103 population, tuber blight resistance inherited independently from foliage blight resistance. Three specific R genes against P. infestans were segregating. The Rpi-abpt and R3a genes function as foliage-specific R genes, whereas the R1 gene acts on both foliage and tuber. In the segregating populations SHRH and RH94-076, tuber and foliage blight resistance correlated significantly, which suggests that resistance in foliage and tuber is conferred by the same gene (could be R3b) and quantitative trait loci (QTL), respectively. In the CE population neither tuber nor foliage resistance was observed.     

Genetic gains in grain yield, net photosynthesis and stomatal conductance achieved in Henan Province of China between 1981 and 2008

Knowledge of the changes in agronomic and photosynthetic traits associated with genetic gains in grain yield potential is essential for an improved understanding of yield-limiting factors and for determining future breeding strategies. The objectives of this study were to identify agronomic and photosynthetic traits associated with genetic gains in grain yield of facultative wheat (Triticum aestivum L.) between 1981 and 2008 in Henan Province, the most important wheat producing area in China. During the 2006-2007 and 2007-2008 crop seasons, a yield potential trial comprising 18 leading and new cultivars released between 1981 and 2008 was conducted at two locations, using a completely randomised block design of three replicates. Results showed that average annual genetic gain in grain yield was 0.60% or 51.30 kg ha⁻¹ yr⁻¹, and the significant genetic improvement in grain yield was directly attributed to increased thousand grain weight which also contributed to the significant increase in harvest index. The genetic gains in rates of net photosynthesis at 10, 20 and 30 days after anthesis were 1.10% (R² = 0.46, P < 0.01), 0.68% (R² = 0.31, P < 0.05) and 6.77% (R² = 0.34, P < 0.05), respectively. The rates of net photosynthesis at 10 (r = 0.58, P < 0.05), 20 (r = 0.59, P < 0.05) and 30 (r = 0.65, P < 0.01) days after anthesis were closely and positively correlated with grain yield. A slight decrease in leaf temperature and an increase in stomatal conductance after anthesis were also observed. Grain yield was closely and positively associated with stomatal conductance (r = 0.69, P < 0.01) and transpiration rate (r = 0.63, P < 0.01) at 30 days after anthesis. Therefore, improvement of those traits was the likely basis of increasing grain yield in Henan Province between 1981 and 2008. The genetic improvement in yield was primarily attributed to the utilization of two elite parents Yumai 2 and Zhou 8425B. The future challenge of wheat breeding in this region is to maintain the genetic gain in grain yield and to improve grain quality, without increasing inputs for the wheat-maize double cropping system.