Quantifying the Extent of Lateral Gene Transfer Required to Avert a `Genome of Eden'

The complex pattern of presence and absence of many genes across different species provides tantalising clues as to how genes evolved through the processes of gene genesis, gene loss and lateral gene transfer (LGT). The extent of LGT, particularly in prokaryotes, and its implications for creating a `network of life' rather than a `tree of life' is controversial. In this paper, we formally model the problem of quantifying LGT, and provide exact mathematical bounds, and new computational results. In particular, we investigate the computational complexity of quantifying the extent of LGT under the simple models of gene genesis, loss and transfer on which a recent heuristic analysis of biological data relied. Our approach takes advantage of a relationship between LGT optimization and graph-theoretical concepts such as tree width and network flow

Waka adventure: Lessons learned from New Zealand

What can we learn from how they use technology in K-12 schools in New Zealand? Join us for a virtual visit to work from students at Pt England School in New Zealand and see how they are using blogs and multimedia podcasting to strengthen student learning (and even their test scores!). (Grades: K-8) Mike Charles is an educational media and technology specialist with a background in curriculum and instruction. He taught for 15 years in Phoenix, Arizona, His interests include the uses of visualization tools in teaching mathematics and science in K-12 education, ways that technology enables student-initiated project learning environments around the globe, and the complexities involved in changing teacher practice

Non-equivalence of antibiotic generic drugs and risk for intensive care patients

Background: The underlying axiom in applying generic drugs is the equivalence of their active ingredient with the (usually more expensive) innovator product, an all-embracing statement with the insidious result that physicians assume that the generic products have been subjected to the same rigorous testing regimens as the brand-name products. The present paper presents novel experimental data on an investigator-blinded comparison between the innovator imipenem antibiotic, and a number of its generics. Methods: Particulate matter contamination of each group was visualized by means of a membrane filter method. Functional studies in an animal model–the dorsal skinfold chamber technique in mice-designed to simulate the state of microcirculatory dysfunction in intensive care patients was performed, in order to assess the influence of the particulate matter of each group on the functional capillary density of the striated skin muscle, after their intravenous injection. Results: The results showed massive particulate contamination of the generics, in a size range relevant for impacting the microcirculation. The particulate contamination contributed in some generic groups to a significant shutdown of tissue perfusion. Conclusion: The presented data underscore the need to raise the regulatory barriers for the entry of generics to the market, well beyond the simplistic proof of “bioequivalence”, which in no measure deals with the essential questions of quality and patient safety. If generics are used, they should be tested by a filter technique and optical microscopy, to ensure the absence especially of small particulate contaminants and their purity

Are the Economics of a Sustainable Maine Forest Sustainable?

Mike LeVert, Charles Colgan and Charles Lawton discuss the transformation of the economic environment of Maine’s forests over the past two decades. Paper companies have sold most of their holdings; residential and conservation demand for land has increased; forestland prices have skyrocketed; and new classes of landowners have different strategies, objectives, and time horizons than the old industrial landowners. The authors believe that management of Maine’s forests must now address changes in the economic environment with the same intensity as threats such as the spruce budworm were addressed if we are to keep Maine’s forests as forests

Harnessing Technology: new modes of technology-enhanced learning: opportunities and challenges

A report commissioned by Becta to explore the potential impact on education, staff and learners of new modes of technology enhanced learning, envisaged as becoming available in subsequent years. A generative framework, developed by the researchers is described, which was used as an analytical tool to relate the possibilities of the technology described to learning and teaching activities. This report is part of the curriculum and pedagogy strand of Becta's programme of managed research in support of the development of Harnessing Technology: Next Generation Learning 2008-14. A system-wide strategy for technology in education and skills. Between April 2008 and March 2009, the project carried out research, in three iterative phases, into the future of learning with technology. The research has drawn from, and aims to inform, all UK education sectors

Reviews

Successful Instructional Diagrams by Ric Lowe, London, Kogan Page, 1993. ISBN: 0–7494–0711–5

Personal Inquiry: lessons learned

The paper describes a school trial carried out to support inquiry learning between formal and informal settings supported by personal mobile technology. The aim of the school trial was to explore how a first version of the PI Toolkit facilitates secondary school students in performing a personally relevant scientific inquiry both in a science classroom as well as at home. An analysis of classroom video and interviews has resulted in a set of incidents from which we have derived design guidelines and challenges for implementing technology-supported inquiry learning where personal technology is used and within which personally relevant investigations are conducted by students

Soil experiment

An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment