台湾青枣设施栽培表现与发展前景初探

辽宁省设施果树生产,由于存在气候、资源、技术等方面的优势,栽培面积、产量和经济效益在逐渐扩大和提高.但从树种、品种结构上看,南方的树种几乎是一个空白.台湾青枣的引进,并在设施栽培上取得一定的成功,无疑打破了辽宁果树设施栽培中只有落叶果树树种的局面,但由于诸多因素的限制,如设施结构保温性能差,技术不到位,果实品质较差,风味淡,商品化程度较低等因素,制约了其发展.从当前果树发展形势来看,台湾青枣应适当栽植,限量发展.     

Initiating and cancer-propagating cells in TEL-AML1-associated childhood leukemia

Understanding cancer pathogenesis requires knowledge of not only the specific contributory genetic mutations but also the cellular framework in which they arise and function. Here we explore the clonal evolution of a form of childhood precursor-B cell acute lymphoblastic leukemia that is characterized by a chromosomal translocation generating a TEL-AML1 fusion gene. We identify a cell compartment in leukemic children that can propagate leukemia when transplanted in mice. By studying a monochorionic twin pair, one preleukemic and one with frank leukemia, we establish the lineal relationship between these "cancer-propagating" cells and the preleukemic cell in which the TEL-AML1 fusion first arises or has functional impact. Analysis of TEL-AML1-transduced cord blood cells suggests that TEL-AML1 functions as a first-hit mutation by endowing this preleukemic cell with altered self-renewal and survival properties.     

An RNA processing activity that debranches RNA lariats

The excised introns of pre-messenger RNA's (pre-mRNA's) and intron-containing splicing intermediates are in a lariat configuration in which the 5' end of the intron is covalently joined by a 2',5'-phosphodiester bond to a specific adenosine residue near the 3' end of the intron. A 2',5'-phosphodiesterase activity in HeLa cell extracts has been detected that debranches RNA lariats, converting them to linear RNA molecules by specific cleavage of the 2',5'-phosphodiester bond. This lariat debranching activity is distinct from previously reported 2',5'-phosphodiesterases with regard to its biochemical and substrate requirements as well as its stringent cleavage specificity. The debranching activity is observed only if the RNA lariats generated during in vitro processing are deproteinized and added back to the extract. These results suggest that during the normal in vitro splicing reaction the 2',5'-phosphodiester bond of RNA lariats is protected from cleavage by the lariat debranching activity.     

Earth's Bow Shock: Elapsed-Time Observations by Two Closely Spaced Satellites

Coordinated observations of the earth's bow shock were made as Vela 3A and Explorer 33 passed within 6 earth radii of each other. Elapsed time measurements of shock motion give directly determined velocities in the range 1 to 10 kilometers per second and establish the existence of two regions, one of large amplitude magnetic "shock" oscillations and another of smaller, sunward, upstream oscillations. Each region is as thick as 1 earth radius, or more.     

Social-ethical issues concerning the control strategy of animal diseases in the European Union: A survey

In 2004 a survey was conducted in the member states of the European Union designed to gain greater insight into the views on control strategies for foot and mouth disease, classical swine fever, and avian influenza with respect to the epidemiological, economic and social-ethical consequences of each of these animal diseases. This article presents the results of the social-ethical survey. A selection of stakeholders from each member state was asked to prioritize issues for the prevention and control of these diseases. A majority of stakeholders chose preventive measures as the preferred issue. An analysis was done to determine whether there were differences in views expressed by stakeholders from member states with a history of recent epidemics and ones without such a history, and whether there were regional differences. There were no differences between member states with or without a history of recent epidemics. There were indeed regional differences between the priority orders from Northern and Southern Europe on the one hand, and from Eastern Europe on the other. Nina E. Cohen is a biologist and is a researcher at the Wageningen University. She is specialized in societal and ethical issues in human–animal relationships. Her current research is focused on the social-ethical issues concerning the prevention and control of foot and mouth disease, classical swine fever and avian influenza. Marcel A.P.M. van Asseldonk has studied animal science. Currently he works at the Institute for Risk Management in Agriculture (IRMA) of the Wageningen University. He is specialized in the design and pricing of insurance policies and animal health funds for the main livestock epidemics. Elsbeth N. Stassen is a veterinarian and professor of Animals and Society at the Wageningen University. Elsbeth Stassen is specialized in animal health, animal welfare and human–animal relationships. She was a member of a governmental welfare committee during the avian influenza epidemic in the Netherlands in 2003.