The Exosome Subunit Rrp44 Plays a Direct Role in RNA Substrate Recognition

The exosome plays key roles in RNA maturation and surveillance, but it is unclear how target RNAs are identified. We report the functional characterization of the yeast exosome component Rrp44, a member of the RNase II family. Recombinant Rrp44 and the purified TRAMP polyadenylation complex each specifically recognized tRNAiMet lacking a single m1A58 modification, even in the presence of a large excess of total tRNA. This tRNA is otherwise mature and functional in translation in vivo but is presumably subtly misfolded. Complete degradation of the hypomodified tRNA required both Rrp44 and the poly(A) polymerase activity of TRAMP. The intact exosome lacking only the catalytic activity of Rrp44 failed to degrade tRNAiMet, showing this to be a specific Rrp44 substrate. Recognition of hypomodified tRNAiMet by Rrp44 is genetically separable from its catalytic activity on other substrates, with the mutations mapping to distinct regions of the protein

Marine Protected Areas in Canada with a Particular Emphasis on Newfoundland: Science, Policy and Implementation at Multiple Institutional Levels

The primary goal of Marine Protected Areas is to conserve and protect part or all of a marine environment through legal or other effective means. MPAs are a global phenomenon that has become part of national level ocean policy and practice in such nations as Australia, Canada, and the US. Marine protected areas depend, for their success, on the development of an informal network of local policy and practice, which varies among communities. They succeed in circumstances where national policy or legal precedent does not dissolve local policy and practice, and where national policy facilitates and can accommodate local arrangements. The collapse of fisheries in the late 20th century in Canada provided the political impetus and policy framework that increased the capacity of the federal government to accommodate local arrangements in marine waters through Canada’s Oceans Act 1996. Two Marine Protected Areas, at Eastport and Gilbert Bay, were designated in Newfoundland and Labrador in 2005 under the Oceans Act, and a third, at Leading Tickles, is in the development stage. Eastport has a research program on lobsters in place, Gilbert Bay has a program on ‘golden cod’, but no research program existed at Leading Tickles. DFO Oceans began to collect data and worked closely with community members to develop research priorities, carry out research projects and develop management programs for each MPA. The provincial government was involved as members of the MPA steering committees, and local representatives provided input. Based on the political momentum for Marine Protected Areas, the second objective of this project was to identify internationally significant science questions for research within Newfoundland and Labrador. Recent research conducted by Memorial University at the Gilbert Bay and Eastport MPAs and the Leading Tickles Area of Interest (AOI) has been a mixture of descriptive and causal science directed at local issues arising within each of the three locations (two MPAs and one AOI). Past research helped to define the scope of some of the science problems in an informal way. This report takes the next step, which is to identify questions significant to both local issues and the understanding of coastal ecosystems by the national and international science community. Sound scientific evidence is needed to identify whether the intended effects are being achieved and to document accompanying effects. The emerging practice is initial science input followed by devolution of monitoring activities to local communities, with guidance from academic scientists. The effectiveness of these scientists would be increased by national initiatives to develop the capacity to guide locally based monitoring efforts. One potential model for science guidance is that used for environmental impact assessment, where monitoring activities are designed as tests of hypotheses concerning effects stated in an impact assessment

Status Report on the Low-Energy Demonstration Accelerator (LEDA)

The 75-keV injector and 6.7-MeV RFQ that comprise the first portion of the cw, 100-mA proton linac for the accelerator production of tritium (APT) project have been built and operated. The LEDA RFQ has been extensively tested for pulsed and cw output-beam currents <=100 mA. Up to 2.2 MW of cw rf power from the 350-MHz rf system is coupled into the RFQ, including 670 kW for the cw proton beam. The emittance for a 93-mA pulsed RFQ output beam, as determined from quadrupole-magnet-scan measurements, is ex x ey = 0.25 x 0.31 (pi mm mrad)2 [rms normalized]. A follow-on experiment, to intentionally introduce and measure beam halo on the RFQ output beam, is now being installed.Comment: Paper TUD14 for the XX International Linac Conference (LINAC2000), 3 pages, 10 figure

Managing LTL properties in Event-B refinement

Refinement in Event-B supports the development of systems via proof based step-wise refinement of events. This refinement approach ensures safety properties are preserved, but additional reasoning is required in order to establish liveness and fairness properties. In this paper we present results which allow a closer integration of two formal methods, Event-B and linear temporal logic. In particular we show how a class of temporal logic properties can carry through a refinement chain of machines. Refinement steps can include introduction of new events, event renaming and event splitting. We also identify a general liveness property that holds for the events of the initial system of a refinement chain. The approach will aid developers in enabling them to verify linear temporal logic properties at early stages of a development, knowing they will be preserved at later stages. We illustrate the results via a simple case study

ILR Impact Brief - Employee Attributions about HR Practices Lead to Customer Satisfaction

[Excerpt] The perceived reasons why management chooses a set of HR practices are linked to employee satisfaction, commitment, and on-the-job behavior. Employees individually make their own attributions about the purposes behind the practices, which are, in turn, associated with employees’ attitudes: a perception that management cares about service (or product) quality and employee well-being is associated with positive attitudes, but a sense that management is intent on cost cutting or employee exploitation is associated with negative attitudes. Furthermore, individual attitudes are shared within work units and in their aggregate are associated with “organizational citizenship behaviors;” i.e., group-level satisfaction and commitment are associated with intra-unit helping behaviors, which are linked to enhanced unit performance and customer satisfaction