Identification of a small RNA containing the trypanosome spliced leader: a donor of shared 5' sequences of trypanosomatid mRNAs?

The 35 nucleotide spliced leader (SL) sequence is found on the 5' end of numerous trypanosome mRNAs, yet the tandemly organized reiteration units encoding this leader are not detectably linked to any of these structural genes. Here we report the presence of a class of discrete small SL RNA molecules that are derived from the genomic SL reiteration units of Trypanosoma brucei, Trypanosoma cruzi, and Leptomonas collosoma. These small SL RNAs are 135, 105, and 95 nucleotides, respectively, and contain a 5'-terminal SL or SL-like sequence. S1 nuclease analyses demonstrate that these small SL RNAs are transcribed from continuous sequence within the respective SL reiteration units. With the exception of the SL sequence and a concensus donor splice site immediately following it, these small RNAs are not well conserved. We suggest that the small SL RNAs may function as a donor of the SL sequence in an intermolecular process that places the SL at the 5' terminus of many trypanosomatid mRNAs

Energy Systems Division Overview

This report presents an overview of the research programs from the energy systems division in the form of viewgraphs

Preliminary Evaluation of NDE Techniques for Structural Ceramics

A preliminary evaluation of several nondestructive testing methods for flaw detection in high-temperature structural ceramic components is being carried out. The ceramics components being investigated include silicon carbide heat-exchanger tubes and silicon nitride rotors. The nondestructive evaluation techniques under consideration include dye-enhanced radiography, holographic interferometry, infrared scanning, acoustic microscopy, acoustic-emission monitoring, acoustic-impact testing, and conventional ultrasonic testing. The capability of each technique to detect critical-size flaws will be discussed. Preliminary results to date\u27 have shown that (a) dye-enhanced radiographic techniques are capable of detecting tight cracks missed with conventional x-ray methods, (b) acoustic microscopy techniques may be useful in detecting and establishing the size of subsurface defects in reaction-bonded silicon nitride, (c) holographic interferometry techniques should be valuable in locating surface cracks in silicon nitride/silicon carbide components, and (d) the results from various silicon carbide tubes suggests that infrared scanning techniques may reveal changes in heat-flow patterns which are related to variations in physical properties. The results for the other techniques mentioned will be discussed. Future efforts in this program, will be directed toward in-depth investigations of the most useful nondestructive techniques

Potential loss of nutrients from different rearing strategies for fattening pigs on pasture

Nutrient load and distribution on pasture were investigated with fattening pigs that: 1) spend a proportion of or their entire life on pasture, 2) were fed either restrictively or ad libitum, and 3) were weaned at different times of the year. The N and P retention in pigs decreased the longer they were kept on pasture. The contents of soil inorganic N and exchangeable K were significantly raised compared to the soil outside the enclosures but with no differences between treatments. Pig grazing did not affect extractable soil P. Regular moving of huts, feeding and water troughs was effective in ensuring that nutrients were more evenly distributed on the paddocks. Grass cover, as determined by spectral reflectance, was not related to the experimental treatments but only to time of year. During spring and summer, grass was present in parts of the paddocks, whereas during autumn and winter the pigs kept grass cover below 10%. Fattening pigs on pasture carries a high risk of nutrient loss and it is concluded that the most environmentally acceptable way of keeping fattening pigs on pasture involves a combination of reduced dietary N intake, reduced stocking rate and seasonal rather than all year production

Asymptotic Behavior of Ext functors for modules of finite complete intersection dimension

Let $R$ be a local ring, and let $M$ and $N$ be finitely generated $R$-modules such that $M$ has finite complete intersection dimension. In this paper we define and study, under certain conditions, a pairing using the modules \Ext_R^i(M,N) which generalizes Buchweitz's notion of the Herbrand diference. We exploit this pairing to examine the number of consecutive vanishing of \Ext_R^i(M,N) needed to ensure that \Ext_R^i(M,N)=0 for all $i\gg 0$. Our results recover and improve on most of the known bounds in the literature, especially when $R$ has dimension at most two

Student participation in the design of learning and teaching: Disentangling the terminology and approaches

Background: Students are ever more involved in the design of educational practices, which is reflected in the growing body of literature about approaches to student participation. Similarities and differences between these approaches often remain vague since the terms are used interchangeably. This confusing and fragmented body of literature hampers our understanding the process and outcomes of student participation and choosing the most suitable approach for it. Method: We identified the three most frequently used terms related to the design of learning and teaching–design-based research (DBR), participatory design (PD), and co-creation–and disentangled the terminology by focusing on relevant definitions, aims, involvement of students, outcomes, and related terminology. Results: Differences between the approaches to student participation can be found in the degree to which students are the central actors and the degree to which the design is informed by educational theory. Conclusion: It is important to align the level of student participation with the purpose of the approach