738 research outputs found

    LAP3, a novel plant protein required for pollen development, is essential for proper exine formation

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    We isolated lap3-1 and lap3-2 mutants in ascreen for pollen that displays abnormal stigma binding.Unlike wild-type pollen, lap3-1 and lap3-2 pollen exine isthinner, weaker, and is missing some connections betweentheir roof-like tectum structures. We describe the mappingand identification of LAP3 as a novel gene that contains arepetitive motif found in b-propeller enzymes. Insertionmutations in LAP3 lead to male sterility. To investigatepossible roles for LAP3 in pollen development, we assayedthe metabolite profile of anther tissues containing developingpollen grains and found that the lap3-2 defect leadsto a broad range of metabolic changes. The largest changeswere seen in levels of a straight-chain hydrocarbon nonacosaneand in naringenin chalcone, an obligate compoundin the flavonoid biosynthesis pathway

    Maximal sprint speed in boys of increasing maturity

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    The purpose of this study was to examine the natural development of the mechanical features of sprint performance in relation to maturation within a large cohort of boys. Three hundred and thirty-six boys (11–15 years) were analyzed for sprint performance and maturation. Maximal speed, stride length (SL), stride frequency (SF), flight time (FT) and contact time (CT) were assessed during a 30m sprint. Five maturation groups (G1–5) were established based on age from peak height velocity (PHV) where G1=>2.5years pre-PHV, G2 = 2.49–1.5years pre-PHV, G3 = 1.49–0.5years pre-PHV, G4 = 0.49years pre- to 0.5years post-PHV and G5 = 0.51–1.5years post-PHV. There was no difference in maximal speed between G1, G2 and G3 but those in G4 and G5 were significantly faster (p .05). SF decreased while CT increased (both p .05) were observed for either variable between G3, G4 and G5. While G1–3 increased their SL, concomitant decreases in SF and increases in CT prevented them from improving maximal speed. Maximal sprint speed appears to develop around and post-PHV as SF and CT begin to stabilize, with increases in maximal sprint speed in maturing boys being underpinned by increasing SL

    Asymmetry During Maximal Sprint Performance in 11- to 16-Year-Old Boys

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    Purpose: The aim of this study was to examine the influence of age and maturation upon magnitude of asymmetry in the force, stiffness and the spatiotemporal determinants of maximal sprint speed in a large cohort of boys. Methods: 344 boys between the ages of 11 and 16 years completed an anthropometric assessment and a 35 m sprint test, during which sprint performance was recorded via a ground-level optical measurement system. Maximal sprint velocity, as well as asymmetry in spatiotemporal variables, modeled force and stiffness data were established for each participant. For analysis, participants were grouped into chronological age, maturation and percentile groups. Results: The range of mean asymmetry across age groups and variables was 2.3–12.6%. The magnitude of asymmetry in all the sprint variables was not significantly different across age and maturation groups (p > .05), except relative leg stiffness (p < .05). No strong relationships between asymmetry in sprint variables and maximal sprint velocity were evident (rs < .39). Conclusion: These results provide a novel benchmark for the expected magnitude of asymmetry in a large cohort of uninjured boys during maximal sprint performance. Asymmetry in sprint performance is largely unaffected by age or maturation and no strong relationships exist between the magnitude of asymmetry and maximal sprint velocity

    ReMashed – Recommendations for Mash-Up Personal Learning Environments

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    Drachsler, H., Pecceu, D., Arts, T., Hutten, E., Rutledge, L., Van Rosmalen, P., Hummel, H. G. K., & Koper, R. (2009). ReMashed - Recommendations for Mash-Up Personal Learning Environments. In U. Cress, V. Dimitrova & M. Specht (Eds.), Learning in the Synergy of Multiple Disciplines. Proceedings of the Fourth European Conference on Technology-Enhanced Learning (EC-TEL 2009) (pp. 788-793). September, 29 - October, 2, 2009, Nice, France. Lecture Notes in Computer Science Vol. 5794. Berlin: Springer-Verlag.The following article presents a Mash-Up Personal Learning Environment called ReMashed that recommends learning resources from emerging information of a Learning Network. In ReMashed learners can specify certain Web2.0 services and combine them in a Mash-Up Personal Learning Environment. Learners can rate information from an emerging amount of Web2.0 information of a Learning Network and train a recommender system for their particular needs. ReMashed therefore has three main objectives: 1. to provide a recommender system for Mash-up Personal Learning Environments to learners, 2. to offer an environment for testing new recommendation approaches and methods for researchers, and 3. to create informal user-generated content data sets that are needed to evaluate new recommendation algorithms for learners in informal Learning Networks.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

    The genetic basis for adaptation of model-designed syntrophic co-cultures.

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    Understanding the fundamental characteristics of microbial communities could have far reaching implications for human health and applied biotechnology. Despite this, much is still unknown regarding the genetic basis and evolutionary strategies underlying the formation of viable synthetic communities. By pairing auxotrophic mutants in co-culture, it has been demonstrated that viable nascent E. coli communities can be established where the mutant strains are metabolically coupled. A novel algorithm, OptAux, was constructed to design 61 unique multi-knockout E. coli auxotrophic strains that require significant metabolite uptake to grow. These predicted knockouts included a diverse set of novel non-specific auxotrophs that result from inhibition of major biosynthetic subsystems. Three OptAux predicted non-specific auxotrophic strains-with diverse metabolic deficiencies-were co-cultured with an L-histidine auxotroph and optimized via adaptive laboratory evolution (ALE). Time-course sequencing revealed the genetic changes employed by each strain to achieve higher community growth rates and provided insight into mechanisms for adapting to the syntrophic niche. A community model of metabolism and gene expression was utilized to predict the relative community composition and fundamental characteristics of the evolved communities. This work presents new insight into the genetic strategies underlying viable nascent community formation and a cutting-edge computational method to elucidate metabolic changes that empower the creation of cooperative communities

    ReMashed – Recommendation Approaches for Mash-Up Personal Learning Environments in Formal and Informal Learning Settings

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    Drachsler, H., Peccau, D., Arts, T., Hutten, E., Rutledge, L., Van Rosmalen, P., Hummel, H. G. K., & Koper, R. (2009). ReMashed – Recommendation Approaches for Mash-Up Personal Learning Environments in Formal and Informal Learning Settings. In F. Wild, M. Kalz, M. Palmér & D. Müller (Eds.), Proceedings of 2nd Workshop Mash-Up Personal Learning Envrionments (MUPPLE'09). Workshop in conjunction with 4th European Conference on Technology Enhanced Learning (EC-TEL 2009): Synergy of Disciplines (pp. 23-30). September, 29, 2009, Nice, France: CEUR workshop proceedings, http://sunsite.informatik.rwth-aachen.de/Publications/CEUR-WS/Vol-506 .This article presents the ReMashed system that recommends learning content from emerging information of a Mash-Up Personal Learning Environment. ReMashed offers advice to find most suitable learning content for individual competence development of lifelong learners. The ReMashed system was initially designed to offer navigational support to lifelong learners in informal learning settings. In this article we want to discuss its ability to be used also in formal learning settings. For this purpose, we discuss the use of two different recommendation approaches for formal and informal learning within ReMashed.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org

    Species-level functional profiling of metagenomes and metatranscriptomes.

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    Functional profiles of microbial communities are typically generated using comprehensive metagenomic or metatranscriptomic sequence read searches, which are time-consuming, prone to spurious mapping, and often limited to community-level quantification. We developed HUMAnN2, a tiered search strategy that enables fast, accurate, and species-resolved functional profiling of host-associated and environmental communities. HUMAnN2 identifies a community's known species, aligns reads to their pangenomes, performs translated search on unclassified reads, and finally quantifies gene families and pathways. Relative to pure translated search, HUMAnN2 is faster and produces more accurate gene family profiles. We applied HUMAnN2 to study clinal variation in marine metabolism, ecological contribution patterns among human microbiome pathways, variation in species' genomic versus transcriptional contributions, and strain profiling. Further, we introduce 'contributional diversity' to explain patterns of ecological assembly across different microbial community types

    Models of everywhere revisited: a technological perspective

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    The concept ‘models of everywhere’ was first introduced in the mid 2000s as a means of reasoning about the environmental science of a place, changing the nature of the underlying modelling process, from one in which general model structures are used to one in which modelling becomes a learning process about specific places, in particular capturing the idiosyncrasies of that place. At one level, this is a straightforward concept, but at another it is a rich multi-dimensional conceptual framework involving the following key dimensions: models of everywhere, models of everything and models at all times, being constantly re-evaluated against the most current evidence. This is a compelling approach with the potential to deal with epistemic uncertainties and nonlinearities. However, the approach has, as yet, not been fully utilised or explored. This paper examines the concept of models of everywhere in the light of recent advances in technology. The paper argues that, when first proposed, technology was a limiting factor but now, with advances in areas such as Internet of Things, cloud computing and data analytics, many of the barriers have been alleviated. Consequently, it is timely to look again at the concept of models of everywhere in practical conditions as part of a trans-disciplinary effort to tackle the remaining research questions. The paper concludes by identifying the key elements of a research agenda that should underpin such experimentation and deployment

    Evaluation of the Norwegian Aid Administration’s Practice of Results-Based Management

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    The purpose of this evaluation has been to improve the aid administration’s current practice of results-based management by documenting how this is currently done and by identifying areas of improvement. Key findings are: - Despite the political commitment to being ‘results orientated’ and ensuring ‘funds deliver results’, there has been no attempt by the aid administration to articulate what ResultsBased Management (RBM) looks like for Norwegian development assistance, how it should operate at what levels, or the value it brings to achieving development outcomes. - In the absence of this vision and strategy, RBM has become associated with demonstrating and reporting results. While the use of RBM in this way might contribute to greater transparency in the use of Norwegian development assistance and improve public understanding and possibly trust in aid, it adds little in terms of contributing to the delivery of better development outcomes by partners. - If the goal of the aid administration is to enable the Norwegian funds to have the biggest contribution to development outcomes as possible, it needs to move beyond simply asking partners for more and better results evidence so as to satisfy reporting requirements, to clearly articulating how it wants to use this data to learn and inform decisions about what and who it funds

    Submission for 2023-2030 Australian Cyber Security Strategy Discussion Paper

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    three main points are as follows: 1. Cyber security and cyber resilience require a shared national strategic vision, supported by laws, policies, advocacy, education, skills, training, and funding. The government is asking everyone – individuals, families, communities, regions, cities, businesses, not-for-profits, governments – to opt-in to that vision. To achieve national alignment and clarity, collaboration, communication, and cooperation will be the crucial mechanisms for success and managing complexity. This requires understanding what is already there (the full complexity of the existing legal and policy framework) before adding new components. 2 2. Cyber security, like many other complex fields,1 exists in shared regulatory space.2 Overlapping regulatory frameworks, functions and authority are normal in a complex field such as cyber security. Research in Australia and elsewhere demonstrates that the best strategy for mitigating the known harms, and harnessing the known benefits, of regulatory overlap is the use of enhanced coordination and cooperation tools. A new Cyber Security Act could achieve this by engaging directly with the coordination and cooperation challenges of multiple agencies, regulators, departments, and stakeholders. However, in enhancing cooperation and coordination, strong accountability and transparency mechanisms must be hardwired into the regulation. 3. New mechanisms for reform must aim to improve cyber security outcomes for society, the economy, and the national interest. A new Cyber Security Act and further amendments to the Security of Critical Infrastructure Act 2018 (Cth) (‘SOCI’) provide publicly scrutinised legislative solutions to the problems cyber security policy seeks to solve. While flexibility for government and businesses is important, government must carefully assess the kind of matters that can be decided in delegated legislation (eg, regulations, declarations, notices), or in co-regulatory and self-regulatory mechanisms (eg, codes of practice, guidelines, assessments, standards), and those which belong in the primary legislation due to: their importance to the operation of a legislative scheme; the need for certainty and clarity around obligations; and to support Australia’s underlying democratic values
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