342 research outputs found
Best practices in heterotrophic high-cell-density microalgal processes: achievements, potential and possible limitations
Microalgae of numerous heterotrophic genera (obligate or facultative) exhibit considerable metabolic versatility and flexibility but are currently underexploited in the biotechnological manufacturing of known plant-derived compounds, novel high-value biomolecules or enriched biomass. Highly efficient production of microalgal biomass without the need for light is now feasible in inexpensive, well-defined mineral medium, typically supplemented with glucose. Cell densities of more than 100g l−1 cell dry weight have been achieved with Chlorella, Crypthecodinium and Galdieria species while controlling the addition of organic sources of carbon and energy in fedbatch mode. The ability of microalgae to adapt their metabolism to varying culture conditions provides opportunities to modify, control and thereby maximise the formation of targeted compounds with non-recombinant microalgae. This review outlines the critical aspects of cultivation technology and current best practices in the heterotrophic high-cell-density cultivation of microalgae. The primary topics include (1) the characteristics of microalgae that make them suitable for heterotrophic cultivation, (2) the appropriate chemical composition of mineral growth media, (3) the different strategies for fedbatch cultivations and (4) the principles behind the customisation of biomass composition. The review confirms that, although fundamental knowledge is now available, the development of efficient, economically feasible large-scale bioprocesses remains an obstacle to the commercialisation of this promising technolog
The Unusual Universality of Branching Interfaces in Random Media
We study the criticality of a Potts interface by introducing a {\it froth}
model which, unlike its SOS Ising counterpart, incorporates bubbles of
different phases. The interface is fractal at the phase transition of a pure
system. However, a position space approximation suggests that the probability
of loop formation vanishes marginally at a transition dominated by {\it strong
random bond disorder}. This implies a linear critical interface, and provides a
mechanism for the conjectured equivalence of critical random Potts and Ising
models.Comment: REVTEX, 13 pages, 3 Postscript figures appended using uufile
What can quasi-periodic oscillations tell us about the structure of the corresponding compact objects?
We show how one can estimate the multipole moments of the space-time,
assuming that the quasi-periodic modulations of the X-ray flux (quasi-periodic
oscillations), observed from accreting neutron stars or black holes, are due to
orbital and precession frequencies (relativistic precession model). The
precession frequencies and can be expressed as
expansions on the orbital frequency , in which the moments enter the
coefficients in a prescribed form. Thus, observations can be fitted to these
expressions in order to evaluate the moments. If the compact object is a
neutron star, constrains can be imposed on the equation of state. The same
analysis can be used for black holes as a test for the validity of the no-hair
theorem. Alternatively, instead of fitting for the moments, observations can be
matched to frequencies calculated from analytic models that are produced so as
to correspond to realistic neutron stars described by various equations of
state. Observations can thus be used to constrain the equation of state and
possibly other physical parameters (mass, rotation, quadrupole, etc.) Some
distinctive features of the frequencies, which become evident by using the
analytic models, are discussed.Comment: accepted in MNRAS; changes made to match version in prin
Mapping Alternative Impact: Alternative approaches to impact from co-produced research
No abstract available
A First Survey on the Diversity of the R Community
The study presented here is a first attempt to capture the demographics and opinions of the R community, starting with the attendees of the useR! conference 2016. One aim of Forwards, the R Foundation taskforce on women and other under-represented groups, is to identify groups that are under-represented in the R community and to further stimulate ideas and take initiatives for widening their participation. Since R is an open-source software with various platforms for exchange, however, it is difficult to obtain information about its community – let alone define this community in the first place. As a starting point, a survey was conducted with the attendees of the useR! conference 2016 to document their sociodemographic and computational backgrounds, experiences and opinions. The present paper gives an overview of the results of this first survey. Most of the analysis focuses on women participants, that are generally under-represented in STEM (Science, Technology, Engineering, Mathematics) disciplines, but the results also show a severe underrepresentation of minorities. A surprising finding concerns a gender difference with regard to the experience with R and the publication of R packages. We investigated possible reasons for this difference by the means of a logistic regression analysis. The self-evident limitations of this first survey are discussed and directions for future research as well as potential means for improvement
are outlined
The Iowa Homemaker vol.15, no.6
A Serve-Yourself party, page 2
Your Own Greeting Cards, by Betty Blanco, page 3
Merry Christmas to a Bookworm, page 3
Something She can Wear, by Kay Hoffman, page 4
Add To Her Dressing Table, by Dorothy Fedderson, page 5
A Tiny Manger Scene, by Gay Starrak, page 6
Package Be Gay! by Ethelavis Hendriks, page 7
Everybody Makes Candy At Christmas, by Stella Mae Brinkman, page 8
Let It be a Tea, by Ruth Cook, page 9
Let Your Christmas Tree Express Itself, by Ruth Kunerth, page 10
A Man “Hec” Student? by Irene Jacobs, page 11
Need and Idea? by Vera Joyce Horswell, page 13
Give Her Silver, page 14
Come Out-of-Doors, by Betty Taylor, page 1
Sequence randomness and polymer collapse transitions
Contrary to expectations based on Harris' criterion, chain disorder with
frustration can modify the universality class of scaling at the theta
transition of heteropolymers. This is shown for a model with random two-body
potentials in 2D on the basis of exact enumeration and accurate Monte Carlo
results. When frustration grows beyond a certain finite threshold, the
temperature below which disorder becomes relevant coincides with the theta one
and scaling exponents definitely start deviating from those valid for
homopolymers.Comment: 4 pages, 4 eps figure
Comparing community-based reading interventions for middle school children with learning disabilities: possible order effects when emphasizing skills or reasoning
IntroductionThere is an abundance of community-based reading programs for school-age children who are struggling learners. The aim of this study was to compare two community-based programs (i.e., skill and reason-based programs) and to analyze any complementary benefits.MethodsIn this randomized cross-over study, 20 children completed two 8-week literacy intervention programs. The skills-based program, Leap to Literacy, focused on explicit teaching and repeated practice of the five key components of literacy instruction (phonemic awareness, phonics, fluency, vocabulary, comprehension). The reason-based program, Wise Words, focused on morphological knowledge, hypothesis testing, and critical thinking.ResultsResults revealed study-wide improvements in phonemic awareness, nonword reading, passage reading accuracy, spelling words and features, and affix identification. There were consistent program by program order effects with robust effects of completing the skills-based program first for phonemic awareness, the reason-based program first for passage reading accuracy, and both programs for affix identification. A significant increase in an oral language measure, recalling sentences, was observed for the group who completed the reason-based program first, although they also started off with a lower initial score.DiscussionFindings indicated improvements from participating in either program. The observed order effects suggest potential additive effects of combining reason- and skills-based approaches to intervention
Best practice coral restoration for the Great Barrier Reef
As the Great Barrier Reef (GBR) continues to degrade through repeated mass bleaching events, crown-of-thorns starfish and major disease outbreaks, and the impacts of intense cyclones, pressure is growing for direct intervention to assist the recovery of reef-building corals. Decreasing coral cover on the GBR and other Australian reefs has been recognised as a serious problem relatively recently in Australia but follows a global trend, with many overseas reefs now highly degraded. Various types of coral restoration, rehabilitation and assisted recovery projects have been trialled overseas for decades and it makes sense to look at what has and hasn’t worked overseas to determine a range of options that may suit GBR conditions. Some direct interventions to assist coral recovery have been trialled in Australia such as transplanting corals, algae removal to promote coral recovery and larval enhancement promoting direct coral recruitment. In addition, after physical damage from cyclones, ship strikes or dragged anchors, local dive operators and dive clubs (permitted or unpermitted) often attempt to assist the recovery of corals by tipping over flipped tabular corals and reattaching broken branching corals or sea fans. These latter assisted recovery techniques are rarely underpinned by scientific data on coral recovery. A lack of best practice guidelines for these actions limits the chance of success and increases the health and safety risks of these activities
Natriuretic peptides and integrated risk assessment for cardiovascular disease. an individual-participant-data meta-analysis
BACKGROUND: Guidelines for primary prevention of cardiovascular diseases focus on prediction of coronary heart disease and stroke. We assessed whether or not measurement of N-terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration could enable a more integrated approach than at present by predicting heart failure and enhancing coronary heart disease and stroke risk assessment.
METHODS: In this individual-participant-data meta-analysis, we generated and harmonised individual-participant data from relevant prospective studies via both de-novo NT-proBNP concentration measurement of stored samples and collection of data from studies identified through a systematic search of the literature (PubMed, Scientific Citation Index Expanded, and Embase) for articles published up to Sept 4, 2014, using search terms related to natriuretic peptide family members and the primary outcomes, with no language restrictions. We calculated risk ratios and measures of risk discrimination and reclassification across predicted 10 year risk categories (ie, <5%, 5% to <7·5%, and ≥7·5%), adding assessment of NT-proBNP concentration to that of conventional risk factors (ie, age, sex, smoking status, systolic blood pressure, history of diabetes, and total and HDL cholesterol concentrations). Primary outcomes were the combination of coronary heart disease and stroke, and the combination of coronary heart disease, stroke, and heart failure.
FINDINGS: We recorded 5500 coronary heart disease, 4002 stroke, and 2212 heart failure outcomes among 95 617 participants without a history of cardiovascular disease in 40 prospective studies. Risk ratios (for a comparison of the top third vs bottom third of NT-proBNP concentrations, adjusted for conventional risk factors) were 1·76 (95% CI 1·56-1·98) for the combination of coronary heart disease and stroke and 2·00 (1·77-2·26) for the combination of coronary heart disease, stroke, and heart failure. Addition of information about NT-proBNP concentration to a model containing conventional risk factors was associated with a C-index increase of 0·012 (0·010-0·014) and a net reclassification improvement of 0·027 (0·019-0·036) for the combination of coronary heart disease and stroke and a C-index increase of 0·019 (0·016-0·022) and a net reclassification improvement of 0·028 (0·019-0·038) for the combination of coronary heart disease, stroke, and heart failure.
INTERPRETATION: In people without baseline cardiovascular disease, NT-proBNP concentration assessment strongly predicted first-onset heart failure and augmented coronary heart disease and stroke prediction, suggesting that NT-proBNP concentration assessment could be used to integrate heart failure into cardiovascular disease primary prevention
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