河北省贯彻落实农药经营许可制度的实践与探索

农药经营环节是整个农药管理链条当中极其重要的一环,是连接农药生产与使用的桥梁和纽带。为更好地落实农药经营许可相关制度,便于操作,河北省制定了配套的规范性文件,并在工作实践中不断探索完善,进一步完善审查审批流程,以解决实际问题,有效推进了全省农药经营许可制度的落实。     

Evaluation of three hormonal protocols for anovulatory lactating cows under regulations restricting the use of estrogenic compounds

When European Union regulations restricted the use of estrogenic compounds in food‐producing animals, refined hormonal protocols were no longer applicable for anovulatory cows. However, Ovsynch and its adaptations are routinely and uniformly applied to all cows regardless of ovarian function. To evaluate their efficacy on anovulatory cows, 143, 147 and 144 anovulatory cows received Ovsynch, Presynch and G6G protocols, respectively. In comparison, 150 cyclic cows were bred without using a synchronized protocol. Results showed that cows in the Presynch group had luteolysis responding to the last prostaglandin F_2α (PGF_2α) injection greater than the Ovsynch group. The serous progesterone levels at the first gonadotropin‐releasing hormone of Ovsych and the last PGF_2α injection was greater in the G6G group than the other two hormonal treatment groups. Concentrations of Ca²⁺ and total protein in cervical mucus in all three hormone‐treated groups before artificial insemination (AI) were significantly different from the controls. The G6G group obtained a greater pregnancy rate compared with Ovsynch and Presynch, but significantly less than the controls. For open cows in the Ovsynch group, estrus rate within 24 days after the first AI was significantly less than the controls. In conclusion, the G6G treatment resulted to better reproductive performance in anovulatory cows.     

论农业自然资源开发利用与保护管理的辩证统一关系

自然界中的一切物质形态都具有统一性,农业自然资源既自成系统,又互成系统,形成农业生态系统,其每一层的结构与功能既相互制约,又相互依赖。因此,在开发利用农业自然资源时,一定要注意其辩证统一关系,把开发利用与保护管理结合起来,使资源得到有效、合理的利用。     

攀西干旱干热河谷退耕还林立地类型的划分及经营模式探讨

四川攀西干旱干热河谷面积巨大，气候类型多样，自然地貌复杂，该区有500万亩耕地将退耕还林，通过对该区自然地理条件调查研究，按照水、热、土等因子将该区划分为四大类型区，即：高海拔干冷区、中海拔干凉区、中低海拔干暖区、低海拔干热区；建立了干旱干热河谷退耕还林地的立地质量评价体系。并根据立地条件和经营条件对该区的退耕还林模式进行了探讨。     

温室控制器网络路由协议仿真

对于嵌入式温室控制器而言,采用无线组网方式构成温室监控系统要比使用现场总线方式组网具有灵活性,并且易于降低系统成本,更易于推广应用。在无线传感器网络路由协议中,传感器节点的能量支持和通信带宽对系统的稳定性与可靠性有很大影响。为此,针对嵌入式温室控制器特点,分析了传感器网络路由协议的工作原理和传播机制,并在OPNET平台上建立了仿真模型。仿真结果表明,定向扩散是一种较为理想的路由协议。     

奶牛场无线传感器网络设计研究

针对奶牛养殖场数据采集时不易实现检测区域的完全覆盖和铺设线缆繁琐的问题,设计了由高性能、低功耗单片机ATmega32L和无线通信模块CRM2400CNC,建立奶牛养殖场无线传感器网络。同时,重点讨论了系统结构、传感器节点的硬软件设计和通信协议等关键问题,结合奶牛场的实际对系统结构的简化进行了研究,并提出了一种新的适合动态网络的跨层技术。试验结果表明,该系统具有结构简单、成本低、功耗低等特点。     

Functions for estimating belowground and whole tree biomass of birch in Norway

Obtaining accurate estimates of national belowground and whole tree biomass is important to better understand the global carbon cycle and to quantify biomass stocks and changes. However, the availability of individual tree belowground biomass functions is generally low due to the difficulty of extracting roots. Allometric birch (Betula pubescens Ehrh. and Betula pendula Roth) biomass functions were derived from 67 trees for belowground and whole tree biomass using diameter at breast height (dbh) and height as the independent variables. The sampled trees spanned a dbh range from 4.0 to 45.5?cm and the functions provided a good fit to the data (RMSE?=?14.2?kg for BG and 40.7?kg for whole tree with dbh as predictor). Belowground, total stem, live crown, and dead branch biomass comprised 29.2%, 52.2%, 18.1%, and 0.5% of the whole tree biomass, respectively. Observed root-to-shoot ratios were between 0.21 and 0.88 with a mean of 0.42. Comparisons with existing belowground birch biomass functions from Fennoscandia indicated considerable differences in estimates between existing functions. The derived data-set for belowground birch biomass is the largest in Fennoscandia and the developed functions are likely the best available for estimating national birch biomass stock and stock change in Norway.     

氮磷钾不同配比模式对水稻性状及产量的影响

通过对北镇地区氮磷钾不同配比模式对水稻的影响效果进行试验。结果表明,推荐施肥区、习惯施肥与推荐施肥搭配区的产量高于其他处理的水稻产量,肥料利用率高些,增产效果好,经济效益显著。其中以推荐施肥N-14.2、P-7、K-7的配方最佳,但此施肥配方易受土壤条件和气候制约,需因地制宜,予以应用。在生产实际中,氮磷钾肥施用以1/3氮肥、全部磷肥、2/3钾肥做底肥,后期追施2/3氮肥和1/3钾肥为最佳施肥模式,能够达到高产、稳产、高效的目的。     

Generalized functions of biomass expansion factors for conifers and broadleaved by stand age,growing stock and site index

Parties to the Kyoto Protocol and/or the United Nations Framework Convention on Climate Change (UNFCCC) are required to account for their direct human-induced carbon emissions and removals including those from forestry and other land use related activities. In most European countries, the forestry related greenhouse gas inventories are largely or exclusively based on converting tree volume data from national forest inventories to biomass using biomass conversion and expansion factors (BCEFs). However, country specific data for many species are often lacking, which considerably increases the uncertainties of the greenhouse gas inventories. The focus of this research was to develop, using internationally published datasets that cover a large geographical area, an extended set of generalized curves of such biomass expansion factors for several species or species groups by age, growing stock and site index.     

An improved session initiation protocol signaling compression algorithm based on lempel ziv storer szymanski and Huffman

Session initiation protocol(SIP) has been chosen as the call/session control protocol in IP multimedia subsystem(IMS). However, large SIP messages create a bottleneck for SIP application in IP multimedia subsystem(IMS) in wireless applications. Based on the SigComp, and by comparing various compression algorithms, lempel ziv storer szymanski(LZSS) is selected as the basic algorithm to compress SIP in accordance with the characteristics of messages in SIP protocol. To further improve the compression ratio, a new algorithm is proposed based on LZSS and Huffman. The performance of the compression algorithm is analyzed via simulation.