884 research outputs found
Collaborative trails in e-learning environments
This deliverable focuses on collaboration within groups of learners, and hence collaborative trails. We begin by reviewing the theoretical background to collaborative learning and looking at the kinds of support that computers can give to groups of learners working collaboratively, and then look more deeply at some of the issues in designing environments to support collaborative learning trails and at tools and techniques, including collaborative filtering, that can be used for analysing collaborative trails. We then review the state-of-the-art in supporting collaborative learning in three different areas – experimental academic systems, systems using mobile technology (which are also generally academic), and commercially available systems. The final part of the deliverable presents three scenarios that show where technology that supports groups working collaboratively and producing collaborative trails may be heading in the near future
An introduction to Graph Data Management
A graph database is a database where the data structures for the schema
and/or instances are modeled as a (labeled)(directed) graph or generalizations
of it, and where querying is expressed by graph-oriented operations and type
constructors. In this article we present the basic notions of graph databases,
give an historical overview of its main development, and study the main current
systems that implement them
Gel-Electrophoresis and Diffusion of Ring-Shaped DNA
A model for the motion of ring-shaped DNA in a gel is introduced and studied
by numerical simulations and a mean-field approximation. The ring motion is
mediated by finger-shaped loops (hernias) that move in an amoeba-like fashion
around the gel obstructions. This constitutes an extension of previous
reptation tube treatments. It is shown that tension is essential for describing
the dynamics in the presence of hernias. It is included in the model as long
range interactions over stretched DNA regions. The mobility of ring-shaped DNA
is found to saturate much as in the well-studied case of linear DNA.
Experiments in polymer gels, however, show that the mobility drops
exponentially with the DNA ring size. This is commonly attributed to
dangling-ends in the gel that can impale the ring. The predictions of the
present model are expected to apply to artificial 2D obstacle arrays (W.D.
Volkmuth, R.H. Austin, Nature 358,600 (1992)) which have no dangling-ends. In
the zero-field case an exact solution of the model steady-state is obtained,
and quantities such as the average ring size are calculated. An approximate
treatment of the ring dynamics is given, and the diffusion coefficient is
derived. The model is also discussed in the context of spontaneous symmetry
breaking in one dimension.Comment: 8 figures, LaTeX, Phys. Rev. E - in pres
Proteolytic enzyme engineering : a tool for wool
One of the goals of protein engineering is to tailor the structure of enzymes to optimize industrial bioprocesses. In the present work, we present the construction of a novel high molecular weight subtilisin, based on the fusion of the DNA sequences coding for Bacillus subtilis prosubtilisin E and for an elastin-like polymer (ELP). The resulting fusion protein was biologically produced in Escherichia coli, purified and used for wool finishing assays. When compared to the commercial protease Esperase, the recombinant subtilisinE-VPAVG220 activity was restricted to the cuticle of wool, allowing a significant reduction of pilling, weight loss and tensile strength loss of wool fibers. Here we report, for the first time, the microbial production of a functionalized high molecular weight protease for controlled enzymatic hydrolysis of wool surface. This original process overcomes the unrestrained diffusion and extended fiber damage which are the major obstacles for the use of proteases for wool finishing applications
The TOBY Study. Whole body hypothermia for the treatment of perinatal asphyxial encephalopathy: A randomised controlled trial
<p>Abstract</p> <p>Background</p> <p>A hypoxic-ischaemic insult occurring around the time of birth may result in an encephalopathic state characterised by the need for resuscitation at birth, neurological depression, seizures and electroencephalographic abnormalities. There is an increasing risk of death or neurodevelopmental abnormalities with more severe encephalopathy. Current management consists of maintaining physiological parameters within the normal range and treating seizures with anticonvulsants.</p> <p>Studies in adult and newborn animals have shown that a reduction of body temperature of 3–4°C after cerebral insults is associated with improved histological and behavioural outcome. Pilot studies in infants with encephalopathy of head cooling combined with mild whole body hypothermia and of moderate whole body cooling to 33.5°C have been reported. No complications were noted but the group sizes were too small to evaluate benefit.</p> <p>Methods/Design</p> <p>TOBY is a multi-centre, prospective, randomised study of term infants after perinatal asphyxia comparing those allocated to "intensive care plus total body cooling for 72 hours" with those allocated to "intensive care without cooling".</p> <p>Full-term infants will be randomised within 6 hours of birth to either a control group with the rectal temperature kept at 37 +/- 0.2°C or to whole body cooling, with rectal temperature kept at 33–34°C for 72 hours. Term infants showing signs of moderate or severe encephalopathy +/- seizures have their eligibility confirmed by cerebral function monitoring. Outcomes will be assessed at 18 months of age using neurological and neurodevelopmental testing methods.</p> <p>Sample size</p> <p>At least 236 infants would be needed to demonstrate a 30% reduction in the relative risk of mortality or serious disability at 18 months.</p> <p>Recruitment was ahead of target by seven months and approvals were obtained allowing recruitment to continue to the end of the planned recruitment phase. 325 infants were recruited.</p> <p>Primary outcome</p> <p>Combined rate of mortality and severe neurodevelopmental impairment in survivors at 18 months of age. Neurodevelopmental impairment will be defined as any of:</p> <p>• Bayley mental developmental scale score less than 70</p> <p>• Gross Motor Function Classification System Levels III – V</p> <p>• Bilateral cortical visual impairments</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN89547571</p
Development of Core Set of Wheat (Triticum spp.) Germplasm Conserved in the National Genebank in India
Dense Cores in Perseus: The Influence of Stellar Content and Cluster Environment
We present the chemistry, temperature, and dynamical state of a sample of 193
dense cores or core candidates in the Perseus Molecular cloud and compare the
properties of cores associated with young stars and clusters with those which
are not. The combination of our NH3 and CCS observations with previous
millimeter, sub-millimeter, and Spitzer data available for this cloud enable us
both to determine core properties precisely and to accurately classify cores as
starless or protostellar. The properties of cores in different cluster
environments and before-and-after star formation provide important constraints
on simulations of star-formation, particularly under the paradigm that the
essence of star formation is set by the turbulent formation of prestellar
cores. We separate the influence of stellar content from that of cluster
environment and find that cores within clusters have (1) higher kinetic
temperatures and (2) lower fractional abundances of CCS and NH3. Cores
associated with protostars have (1) slightly higher kinetic temperatures (2)
higher NH3 excitation temperatures), (3) are at higher column density, have (4)
slightly more non-thermal/turbulent NH3 linewidths, have (5) higher masses and
have (6) lower fractional abundance of CCS. We find that neither cluster
environment nor protostellar content makes a significant difference to the
dynamical state of cores as estimated by the virial parameter -- most cores in
each category are gravitationally bound. Overall, cluster environment and
protostellar content have a smaller influence on the properties of the cores
than is typically assumed, and the variation within categories is larger than
the differences between categories.Comment: 28 pages, 17 figures. Accepted to Ap
Poverty and mental health: the work of the female sanitary inspectors in Bradford (c. 1901–1912)
This is the final version of the article. Available from Palgrave Macmillan via the DOI in this record.Although there are many excellent studies of the work of pioneer women
public health officers, few accounts dwell on mental health issues or discuss any relationship
that such staff might have understood to exist between poverty and mental health in the early
twentieth century. This is a remarkable omission considering that social and feminist historians
have highlighted the problems created by the way early practitioners sought to
manage poverty and arguably the poor. Drawing on records created by Female Sanitary
Inspectors (FSIs) in Bradford, this study chronicles distressing economic and social conditions
but also reveals encounters between the staff and people experiencing mental health problems
and mental health crises. The ways in which the FSIs chose to both make and deny
links between the abject poverty witnessed in the slum districts and cases of mental disorder
forms an important strand to the analysis that follows. Interestingly, it is the well-being of the
staff that emerges as a persistent and even over-riding concern.This work was generously supported by Wellcome Trust Grant 074999. This was a personal fellowship entitled 'The Medical Officer of Health and the Organisation of Health Visiting as a Comprehensive Community Health Service, 1906-1974'
Brain ultrasonography findings in neonates with exposure to cocaine during pregnancy
Background: Cocaine exposure during pregnancy has been reported to have detrimental effects on the fetus. Objective: To describe the findings on cranial ultrasonography (CUS) as part of a neonatal screening programme for exposed neonates. Materials and methods: The study was a semiprospective analysis of a 12-year cohort of neonates born to mothers who had used cocaine during their pregnancy and who had follow-up according to a strict clinical protocol. Results: In total, 154 neonates (78 boys, 76 girls) were included, of whom 29 (19%) were born preterm, and 125 (81%) were born full-term. Abnormalities on CUS were seen in 37 neonates (24%; 95% CI 18-31%). The abnormalities were classified as minor in 20 (13%; 95% CI 9-19%) and mildly abnormal in 17 (11%; 95% CI 7-17%). None of the infants showed severe abnormalities. The abnormalities were not associated with the duration or maximum amount of cocaine use during pregnancy. Conclusion: None of the infants had severe abnormalities. Detected abnormalities were not correlated with the duration or maximum amount of cocaine use. Given these findings, we feel that routine cranial ultrasonography in this population is not warranted
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