1,390 research outputs found
Emergence of the vowel space in very young children with Down syndrome: An exploratory case study
The current study presents the preliminary results of an investigation into the development of the vowel space in one female child with Down syndrome (DS). Vowel productions at five points in time, ranging from 1;0 to 3;8 years of age, have been analysed to produce age-specific F1-F2 vowel plots and to calculate metrics quantifying changes in their size and dimensions. The results show that changes in DS vowel space area and shape are non-systematic, lacking the definite developmental trajectories present in the productions of typically developing children. An explanation of outcomes using the DIVA model of speech acquisition is proposed
The genetic organisation of prokaryotic two-component system signalling pathways
BACKGROUND: Two-component systems (TCSs) are modular and diverse signalling pathways, involving a stimulus-responsive transfer of phosphoryl groups from transmitter to partner receiver domains. TCS gene and domain organisation are both potentially informative regarding biological function, interaction partnerships and molecular mechanisms. However, there is currently little understanding of the relationships between domain architecture, gene organisation and TCS pathway structure. RESULTS: Here we classify the gene and domain organisation of TCS gene loci from 1405 prokaryotic replicons (>40,000 TCS proteins). We find that 200 bp is the most appropriate distance cut-off for defining whether two TCS genes are functionally linked. More than 90% of all TCS gene loci encode just one or two transmitter and/or receiver domains, however numerous other geometries exist, often with large numbers of encoded TCS domains. Such information provides insights into the distribution of TCS domains between genes, and within genes. As expected, the organisation of TCS genes and domains is affected by phylogeny, and plasmid-encoded TCS exhibit differences in organisation from their chromosomally-encoded counterparts. CONCLUSIONS: We provide here an overview of the genomic and genetic organisation of TCS domains, as a resource for further research. We also propose novel metrics that build upon TCS gene/domain organisation data and allow comparisons between genomic complements of TCSs. In particular, 'percentage orphaned TCS genes' (or 'Dissemination') and 'percentage of complex loci' (or 'Sophistication') appear to be useful discriminators, and to reflect mechanistic aspects of TCS organisation not captured by existing metrics
Reflections on a coaching pilot project in healthcare settings
This paper draws on personal reflection of coaching experiences and learning as a coach to consider the relevance of these approaches in a management context with a group of four healthcare staff who participated in a pilot coaching project. It explores their understanding of coaching techniques applied in management settings via their reflections on using coaching approaches and coaching applications as healthcare managers. Coaching approaches can enhance a managerâs skill portfolio and offer the potential benefits in terms of successful goal achievement, growth, mutual learning and development for both themselves and staff they work with in task focused scenarios
Learning to produce and transcribe cardinal vowels: speech and language therapy studentsâ perception of task difficulty
Learning vowel transcription skills is crucial to function as a Speech and Language Therapist (SLT). However, vowel transcription is commonly regarded as particularly difficult and therefore often avoided. Despite the importance of accurate transcriptions, little is known about all the factors that influence the process of learning vowel transcription, which usually includes the learning of the Cardinal Vowel (CV) system. There are only a few studies that investigate how CVs are learnt and what factors lead to successful learning. The current study reports students' perceived difficulty of producing and transcribing CVs as a first step to identify how perceived difficulty affects phonetic learning. Perceived difficulty ratings for the production and transcription of 12 CVs collected from 155 students studying towards a qualification as an SLT were analysed. The results show that the classificatory features correlate with the perceived task difficulty of production and transcription. Implications for teaching are outlined
Human immunodeficiency virus (HIV) in developing countries.
The human immunodeficiency virus (HIV) is causing the most destructive epidemic of recent times, having been responsible for the deaths of more than 25 million people since it was first recognised in 1981. This global epidemic remains out of control, with reported figures for 2005 of 40 million people infected with HIV. During 2005 there were 4.9 million new infections, showing that transmission is not being prevented, and there were 3.1 million deaths from the acquired immunodeficiency syndrome (AIDS), reflecting the lack of a definitive cure and the limited access to suppressive antiretroviral treatment in the developing countries that are most severely affected. The current state of the epidemic and the response to date are here reviewed. Present and future opportunities for prevention, treatment and surveillance are discussed, with particular reference to progress towards an HIV vaccine, the expansion of the provision of highly active antiretroviral therapy, and the need to focus control programmes on HIV as an infectious disease, rather than as a development issue
Drosophila Parkin requires PINK1 for mitochondrial translocation and ubiquitinates Mitofusin
Loss of the E3 ubiquitin ligase Parkin causes early onset Parkinson's disease, a neurodegenerative disorder of unknown etiology. Parkin has been linked to multiple cellular processes including protein degradation, mitochondrial homeostasis, and autophagy; however, its precise role in pathogenesis is unclear. Recent evidence suggests that Parkin is recruited to damaged mitochondria, possibly affecting mitochondrial fission and/or fusion, to mediate their autophagic turnover. The precise mechanism of recruitment and the ubiquitination target are unclear. Here we show in Drosophila cells that PINK1 is required to recruit Parkin to dysfunctional mitochondria and promote their degradation. Furthermore, PINK1 and Parkin mediate the ubiquitination of the profusion factor Mfn on the outer surface of mitochondria. Loss of Drosophila PINK1 or parkin causes an increase in Mfn abundance in vivo and concomitant elongation of mitochondria. These findings provide a molecular mechanism by which the PINK1/Parkin pathway affects mitochondrial fission/fusion as suggested by previous genetic interaction studies. We hypothesize that Mfn ubiquitination may provide a mechanism by which terminally damaged mitochondria are labeled and sequestered for degradation by autophagy
Flaming dormant alfalfa for pest control
Alfalfa (Medicago sativa Leyss) is an important forage crop whose production is hampered by pests, including the alfalfa weevil (Hypera postica Gyllenhal) which is a major problem in many areas. Flaming during dormancy could be an alternative control measure. Late fall and early spring flaming at three intensities were compared with pesticide and no treatment for their effects on alfalfa weevil damage and weed density. In four site-years, flaming at high intensity generally reduced weevil damage to alfalfa. When winter annual broadleaf weeds were prevalent, flaming decreased their density. When fall and spring flaming effects were different, spring flaming gave better results
Gas-cooling by dust during dynamical fragmentation
We suggest that the abrupt switch, from hierarchical clustering on scales
larger than 0.04 pc, to binary (and occasionally higher multiple) systems on
smaller scales, which Larson has deduced from his analysis of the grouping of
pre-Main-Sequence stars in Taurus, arises because pre-protostellar gas becomes
thermally coupled to dust at sufficiently high densities. The resulting change
from gas-cooling by molecular lines at low densities to gas-cooling by dust at
high densities enables the matter to radiate much more efficiently, and hence
to undergo dynamical fragmentation.
We derive the domain where gas-cooling by dust facilitates dynamical
fragmentation. Low-mass (i.e. solar mass) clumps - those supported mainly by
thermal pressure - can probably access this domain spontaneously, albeit rather
quasistatically, provided they exist in a region where external perturbations
are few and far between. More massive clumps probably require an impulsive
external perturbation, for instance a supersonic collision with another clump,
in order for the gas to reach sufficiently high density to couple thermally to
the dust. Impulsive external perturbations should promote fragmentation, by
generating highly non-line ar substructures which can then be amplified by
gravity during the subsequent collapse.Comment: 9 pages, 4 figures, accepted by MNRA
Dynamically triggered star formation in giant molecular clouds
A Lagrangian, particle-based numerical method (tree code gravity plus
smoothed particle hydrodynamics) was used to simulate clump-clump collisions
occurring within GMCs.
The collisions formed shock-compressed layers, out of which condensed
approximately co-planar protostellar discs of 7-60 solar masses and 500-1000AU
radius. Binary and multiple systems were the usual final state. Lower mass
objects were also produced, but commonly underwent disruption or merger. Such
objects occasionally survived by being ejected via a three-body slingshot event
resulting from an encounter with a binary system.
Varying the impact parameter, b, altered the processes by which the
protostellar systems formed. At low b a single central disc formed initially,
and was then spun-up by an accretion flow, causing it to produce secondaries
via rotational instabilities. At mid b the shocked layer w hich formed
initially broke up into fragments, and discs were then formed via fragment
merger. At large b single objects formed within the compressed leading edge of
each clump. These became unbound from each other as b was increased further.
The effect of changing numerical factors was examined by : (i) colliding
clumps which had been re-oriented before the collision (thus altering the
initial particle noise), and (ii) by quadrupling the number of particles in
each clump (thus increasing the resolution of the simulation). Both changes
were found to affect the small-scale details of a collision, but leave the
large scale morphology largely unaltered.
It was concluded that clump-clump collisions provide a natural mechanism by
which multiple protostellar systems may form.Comment: 15 pages, 12 low resolution figures in 50 files, accepted by MNRA
Jet-Induced Emission-Line Nebulosity and Star Formation in the High-Redshift Radio Galaxy 4C41.17
The high redshift radio galaxy 4C41.17 consists of a powerful radio source in
which previous work has shown that there is strong evidence for jet-induced
star formation along the radio axis. We argue that nuclear photoionization is
not responsible for the excitation of the emission line clouds and we construct
a jet-cloud interaction model to explain the major features revealed by the
data. The interaction of a high-powered jet with a dense cloud in the halo of
4C41.17 produces shock-excited emission-line nebulosity through ~1000 km/s
shocks and induces star formation. The CIII to CIV line ratio and the CIV
luminosity emanating from the shock, imply that the pre-shock density in the
line-emitting cloud is high enough (~1-10 cm^-3) that shock initiated star
formation could proceed on a timescale of order a few x 10^6 yrs, well within
the estimated dynamical age of the radio source. Broad (FWHM ~ 100 - 1400 km/s)
emission lines are attributed to the disturbance of the gas cloud by a partial
bow--shock and narrow emission lines (FWHM ~ 500 - 650 km/s) (in particular
CIV) arise in precursor emission in relatively low metallicity gas. The implied
baryonic mass ~ 8 \times 10^{10} solar masses of the cloud is high and implies
that Milky Way size condensations existed in the environments of forming radio
galaxies at a redshift of 3.8. Our interpretation of the data provides a
physical basis for the alignment of the radio, emission-line and UV continuum
images in some of the highest redshift radio galaxies and the analysis
presented here may form a basis for the calculation of densities and cloud
masses in other high redshift radio galaxies.Comment: 18 pages, 5 figures; uses astrobib.sty and aaspp4.sty. Better
versions of figures available via anonymous from
ftp://mso.anu.edu.au:pub/pub/geoff/4C41.1
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