猪冷冻精液的生产及应用

猪精液冷冻保存技术可延长精液的保存时间,适应精液远距离运输,与猪人工授精技术配合应用,可以大幅度降低公猪的饲养数量和引种成本。文章通过综述猪冷冻精液的生产及应用现状,分析影响猪精液冷冻保存和解冻复苏等重要环节的因素。

后备公猪的科学选育与利用

后备公猪的科学选育及利用直接影响猪场制种效果和经济效益,同时也能体现规模化猪场的制种技术与水平。文章针对后备公猪选育的基本环节和操作要点,从如何选种选育、科学饲养管理、合理配种利用等方面进行系统阐述,为规模化猪场后备公猪生产提供技术指导和参考依据。

猪场财务报销软件设计与使用

1背景与意义,随着养猪生产集约化发展,生猪规模化养殖模式得到了迅速发展,猪场的财务管理压力也越来越大,特别是科研系统单位的试验猪场,报销手续相对繁琐,填写单据及需要提供的附件资料较多,目前猪场的传统手工财务报销模式已经制约了猪场财务报销的效率和质量的提升,不利于促进养猪生产效率的提高。

苯并噁嗪的阻燃改性研究进展

基于自身低熔融黏度、固化过程不需添加催化剂、聚合过程中无小分子释放以及固化后树脂卓越的力学性能,近年来苯并噁嗪引起了学术界和诸多工业制造及生产行业的极大兴趣。尽管苯并噁嗪单体含氧、氮六元杂环结构,开环后聚合生成类似酚醛树脂的网状结构,不易燃烧,但仍无法满足高阻燃场合的应用需求。文中从苯并噁嗪的本体改性、共聚改性及物理共混改性三方面,综述了近些年苯并噁嗪树脂阻燃改性的一些研究成果,概述了其作为阻燃协效剂的应用,并对其阻燃改性方法及阻燃应用方向进行了展望。

非洲猪瘟疫情形势下轮回杂交在养猪生产中的应用与前景分析

文章针对非洲猪瘟疫情形势下我国商品肉猪杂交繁育体系现状及存在的问题,探讨了轮回杂交在养猪生产中的实际作用和意义,分析了非洲猪瘟持续流行的背景下,轮回杂交可能对我国生猪养殖业产生的影响和发展前景,为商品肉猪生产提供借鉴。

Sequestration of carbon as carbonate in the critical zone：insights from the Himalayas and Tibetan Plateau

The carbon pool stored in soil carbonate is comparable to the soil organic carbon.Therefore,secondary calcite precipitation in supersaturated catchment could be an important,yet poorly constrained,carbon sink within the modern global carbon cycle.The chemical analysis of some dissolved species transported by rivers,such as elevated Sr/Ca and Mg/Ca ratios but also heavy stable Ca isotopic compositions,witness the formation of secondary calcite in rivers draining arid regions.However,in areas affected by active tectonics and rapid physical erosion,co-variations in the fluvial Sr/Ca and Mg/Ca ratios could also be related to incongruent carbonate weathering processes.Here,we present a model to assess the roles played by incongruent carbonate dissolution and secondary calcite precipitation in modern weathering processes.We tested and applied the model to rivers draining the Himalayan–Tibetan region.The results suggest that regional aridity in the drainage basin promotes carbon sequestration as secondary carbonate but that for a given runoff,incongruent dissolution of carbonate possibly related to rapid physical erosion amplifies such sequestration.The isotopic compositions(^(13)C/^(12)C and^(18)O/^(16)O)of detrital carbonate transported by the main rivers in South and South-East Tibet imply that around 1%of the suspended material transported by those rivers corresponds to secondary carbonate and can represent between 5%and 15%of the alkalinity flux.Most of these alkalinity transported as particulate material is,nevertheless related to the weathering of carbonate lithologies and is also subjected to dissolution prior its final storage in sedimentary basins.However,on glacial-interglacial timescale this will amplify the significant role of mountain weathering on climatic variations.

Evidence-based practice with knowledge, attitude and practice of ophthalmic nursing staffs: a cross-sectional study in south China

Background:This study aims to investigate the current status and influencing factors of evidence-based practice(EBP)with knowledge,attitude and practice(KAP)of ophthalmic nursing staffs in south China.Methods:Using a convenient sampling method,we selected 429 ophthalmic nursing staffs from 28 ophthalmology specialist hospitals or general hospitals in south China,and investigated their general information and implemented the evidence-based practice questionnaire(EBPQ).Results:The scores of EBP and KAP of ophthalmic nursing staffs in south China from high to low were as follows:practical attitude(4.85±1.07 points),practical behavior(4.42±1.14 points),practical knowledge and skills(4.30±0.65 points).The single factor analysis results showed that the first graduation degree,technical title,scientific research achievements,whether or not participate in EBP training,the frequency of reading literature at ordinary time,and whether or not participate in EBP project were the influencing factors of EBP level;the multi-factor analysis results showed that EBP attitude,EBP knowledge and skills,whether or not participate in EBP training were independent influencing factors of EBP.Conclusions:The ophthalmic nursing staffs in south China have a positive attitude towards EBP,however,their EBP knowledge,skills and behavioral capabilities need to be focused and improved.The ophthalmic nursing administrators should fully master the factors affecting the implementation of EBP,and take effective intervention measurement to improve the EBP abilities of ophthalmic nursing staffs,and promote the development of EBP in ophthalmology specialty.

Neogene integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

The remarkable uplift of the Tibetan Plateau in the Neogene had great impacts on the climate and environment of East Asia and even the world.Therefore,establishment of the Neogene stratigraphic framework of the Tibetan Plateau is of great significance to research in various fields of geosciences.Based on marine sediments,the international chronostratigraphic system of the Neogene is divided into six stages in the Miocene and two stages in the Pliocene.Since the beginning of the Cenozoic,the share of terrestrial strata on continents has increased rapidly.By the Neogene,it had far exceeded that of marine strata,and almost all deposits on the Tibetan Plateau and its surrounding areas were terrestrial strata.In China,the Miocene includes five stages and the Pliocene includes two stages.Except for the Tunggurian of the Miocene,which has a lower boundary at 15 Ma,the other stages have the same paleomagnetic definitions and time intervals as the corresponding international marine stages.Mammalian fossils play a very important role in the division and correlation of Cenozoic terrestrial strata,and rodent,carnivore,proboscidean,perissodactyl and artiodactyl fossils are especially important in Neogene terrestrial biostratigraphy.There are many basins with well-exposed strata and abundant mammalian fossils in the Tibetan Plateau.The lower boundary stratotype sections of the Neogene Xiejian and Bahean stages are located respectively in the Xining and Linxia basins,and there are precise paleomagnetic dates in coordination with mammalian fossils.The lower boundary stratotypes of other stages can also be effectively determined in the Tibetan Plateau.Many first appearing mammalian genera in East Asia also appeared in the Tibetan Plateau and its surrounding areas,especially in the Linxia Basin on the northeast margin and in the Siwaliks on the southwest margin.Among them,Prodeinotherium first appeared at the bottom of the Miocene in the Siwaliks,and the earliest Hipparion of the Old World first appeared at the bottom of the Bahean Stage in the Linxia Basin.Carbon and oxygen isotope analysis of enamel and paleosols of Cenozoic sediments and mammal fossils in the Tibetan Plateau and its surrounding areas have been used to reconstruct the climate,environment and vegetation development characteristics,and revealed that these changes were not only related to global change,but also had regional features.Evidence of the Late Miocene C4plant expansion event based on carbon isotope changes comes from the southern margin of the Tibetan Plateau,but in sharp contrast,δ13C indicates that there was still no clear or significant C4plant signal on the northern margin of the Tibetan Plateau until the end of the Neogene.Theδ18O analysis shows that there were several major climate change events in the Cenozoic,especially in the Late Miocene at about 7 Ma,when positive drift ofδ18O indicates that the northern and southern sides of the Tibetan Plateau were changing to drier environments.The strong uplift of the Tibetan Plateau in the Late Miocene strengthened the thermal contrast between sea and land,which strengthened monsoon circulation and led to the expansion of C4vegetation in South Asia.However,the East Asian summer monsoon,which can bring atmospheric precipitation and a climate suitable for C4plants to northern China,was not enough to affect the northern Tibetan Plateau.The Tibetan Plateau on the whole rose to an altitude of about 3000 m in the Miocene,becoming a barrier to mammalian migration;it reached its modern altitude of more than 4000 m in the Pliocene,thus forming a cryosphere environment,which led to the emergence of ancestral types of the Ice Age fauna.

西宁盆地新生代磁性地层研究新进展

西宁盆地是青藏高原向东北扩展生长的“前哨”,也是东亚季风湿润气候向中亚内陆干旱气候过渡的核心地带.盆地内堆积了厚层、几乎连续的以细粒河湖相为主的新生代沉积物,含有丰富的哺乳动物化石,尤以中国早中新世标准动物群—谢家动物群而著名.顶部河流阶地上覆盖了厚层风成粉尘堆积,它们详细记录了亚洲内陆干旱和东亚季风演化、动植物演替以及黄河形成与高原隆升过程等重要信息.

Uplift of the Tibetan Plateau and environmental changes

Major progress, problems, and challenges of recent investigation of the Tibetan Plateau uplift processes and resulting environmental changes are reviewed and summarized briefly, which especially covers the National Tibetan Research Projects of the Chinese Eighth (1992-1996) and Ninth (1997-2001) 'Five-Year Projects'. The Tibetan Plateau uplift is a complicated multiple cyclic process. The Gangdise and Himalayas began to uplift in the

Major advances in studies of the physical geography and living environment of China during the past 70 years and future prospects

The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.

4100万年印度季风增强和扩张的古地理控制

印度季风是亚洲季风的主要水汽来源.但截至目前我们对印度季风的形成演化和内在驱动机制的理解仍十分有限.有关印度季风新生代早期形成的报道均在热带季风区,受控于赤道辐合带的季节摆动,而与青藏高原隆起无关.然而,此区以外准确定年的印度季风记录对于揭示印度季风如何扩展并了解其驱动因素至关重要.位于亚热带云南的古环境记录揭示始新世早期的干旱气候环境在4100万年时突变为季节性湿润环境,指示印度季风在4100万年时已到该区.综合集成分析认为印度与亚洲板块的完全碰撞及其导致的古地理巨变(新特提斯海关闭、副特提斯海急退、高原南部边界快速北移和高原中部隆升),可能共同推动了印度季风在约4100万年时的增强和向北扩展.

Eolian sand deposition and its environmental significance in the northeastern margin of the Qinghai-Xizang Plateau

The dry climate which appeared about 8-7 Ma ago in South Asia has been interpreted as results of the intensification of Asian monsoon caused by the uplift of the Qinghai-Xizang Plateau at its maximum altitude around that time. Whether it is or not, it is a critical problem. A total of 55 samples were taken from the Tertiary red earth and Quaternary lacustrine deposits and loess in the Linxia Basin which is located in the northeastern margin of the

New insights on the age of the Mengyejing Formation in the Simao Basin,SE Tethyan domain and its geological implications

Knowledge on the origin and mechanism of the large potash formation in the southeast Tethyan tectonic domain are still under debate,one of which mainly due to the controversial ages of the potash-bearing strata.Here we present a detailed detrital zircon U-Pb geochronologic-magnetostratigraphic study of the potash-bearing Mengyejing(MYJ)Formation(Fm)from the Simao Basin.948 paleomagnetic cores and 4 detrital zircon U-Pb samples were collected from a 932-m thick Jiangcheng section.Thermal demagnetization isolated 857 primary characteristic remnant magnetization(ChRM)directions,indicated by positive reversals and fold tests and petrologic examinations.Seven normal and seven reversed polarity zones were identified and correlated well with chrons C27r to C34n of the geomagnetic polarity timescale(GPTS2012),yielding the first known age sequence of>112 to~63 Ma for the MYJ Fm.The ages for the potash bearing strata in the Simao commenced~20 Ma earlier than those in the adjacent Khorat basins,opposite to the traditional viewpoint that the former would rather correspond to the middle and lower parts of the latter.Given the paleogeographic reconstruction of likely a pan-Simao-Khorat basin during the Cretaceous,~85 Ma would be another important potential period for future potash exploration in the Simao Basin.

Environmental and rock magnetic studies of rapid fluctuations of Asian summer monsoon during the last interglacial maximum(MIS 5e)

A systematic environmental rock magnetic study of a century-millennial scale loesspaleosol sequence of the last interglacial in the Jiuzhoutai well section, Lanzhou, on the western Loess Plateau demonstrates that Asian summer monsoon experienced fast and large oscillations manifesting as three peaks and two valleys lasling about 1—2 ka. Valley 4 with a central age of 120.5 ka is the most evident, suggesting that summer monsoon was weakened nearly to a level in glaciations. This indicates that summer monsoon has a nature of instability in centurymillennial scale change in the last interglacial.

East Asian monsoon intensification promoted weathering of the magnesium-rich southern China upper crust and its global significance

The Oligocene-Miocene boundary Asian climatic reorganization linked to the northward migration of the East Asian monsoon into subtropical China is a potentially important but poorly constrained atmospheric CO_(2) consumption process.Here,we performed a first-order estimate of the CO_(2) consumption induced by silicate chemical weathering and organic carbon burial in subtropical China related to this climatic reorganization.Our results show that an increase in long-term CO_(2 )consumption by silicate weathering varies from 0.06×10^(12)to 0.87×10^(12)mol yr^(-1)depending on erosion flux reconstructions,with an~50%contribution of Mg-silicate weathering since the late Oligocene.The organic carbon burial flux is approximately 25%of the contemporary CO_(2) consumption by silicate weathering.The results highlight the significant role of weathering of the Mg-rich upper continental crust in East China,which would contribute to the rapid decline in atmospheric CO_(2) during the late Oligocene and the Neogene rise in the seawater Mg content.If this climatic reorganization was mainly induced by the Tibetan Plateau uplift,our study suggests that the growth of the Himalayan-Tibetan Plateau can lead to indirect modification of the global carbon and magnesium cycles by changing the regional hydrological cycle in areas of East Asia that are tectonically less active.