457 research outputs found
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Evaluating MI512: An information literacy course for PhD students
The purpose of this paper is to provide an overview of a six-week information literacy course for research students that was redesigned following the librarians undertaking the Postgraduate Certificate in Teaching in Higher Education. The paper presents a case study and evaluation of the impact of a teaching programme. Findings — Research students appreciate and value the expertise of library staff and are prepared to devote considerable time to an information literacy programme. The programme received excellent feedback. There is no summative assessment associated with the course and so no quantitative measure of improvement in learning. The paper provides a model programme other librarians can adapt for use at their own institution. Extended doctoral level information literacy courses are relatively uncommon and demonstrates the benefit of this type of course, to research
Trapped ions in Rydberg-dressed atomic gases
We theoretically study trapped ions that are immersed in an ultracold gas of
Rydberg-dressed atoms. By off-resonant coupling on a dipole-forbidden
transition, the adiabatic atom-ion potential can be made repulsive. We study
the energy exchange between the atoms and a single trapped ion and find that
Langevin collisions are inhibited in the ultracold regime for these repulsive
interactions. Therefore, the proposed system avoids recently observed ion
heating in hybrid atom-ion systems caused by coupling to the ion's radio
frequency trapping field and retains ultracold temperatures even in the
presence of excess micromotion.Comment: 9 pages, 5 figures including appendice
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TeenTech: getting young people engaged with information literacy
Rebecca Jones, Maggie Philbin and Jane Secker talk about TeenTech’s Research and Information Literacy Award, sponsored by ILG, which aims to show how information literacy underpins the acquisition of digital skills
Resonant vibrations, peak broadening and noise in single molecule contacts: beyond the resonant tunnelling picture
We carry out experiments on single-molecule junctions at low temperatures,
using the mechanically controlled break junction technique. Analyzing the
results received with more than ten different molecules the nature of the first
peak in the differential conductance spectra is elucidated. We observe an
electronic transition with a vibronic fine structure, which is most frequently
smeared out and forms a broad peak. In the usual parameter range we find strong
indications that additionally fluctuations become active even at low
temperatures. We conclude that the electrical field feeds instabilities, which
are triggered by the onset of current. This is underscored by noise
measurements that show strong anomalies at the onset of charge transport
Transcriptome profiling reveals expression signatures of cranial neural crest cells arising from different axial levels
Background: Cranial neural crest cells (NCCs) are a unique embryonic cell type which give rise to a diverse array of derivatives extending from neurons and glia through to bone and cartilage. Depending on their point of origin along the antero-posterior axis cranial NCCs are rapidly sorted into distinct migratory streams that give rise to axial specific structures. These migratory streams mirror the underlying segmentation of the brain with NCCs exiting the diencephalon and midbrain following distinct paths compared to those exiting the hindbrain rhombomeres (r). The genetic landscape of cranial NCCs arising at different axial levels remains unknown. Results: Here we have used RNA sequencing to uncover the transcriptional profiles of mouse cranial NCCs arising at different axial levels. Whole transcriptome analysis identified over 120 transcripts differentially expressed between NCCs arising anterior to r3 (referred to as r1-r2 migratory stream for simplicity) and the r4 migratory stream. Eight of the genes differentially expressed between these populations were validated by RT-PCR with 2 being further validated by in situ hybridisation. We also explored the expression of the Neuropilins (Nrp1 and Nrp2) and their co-receptors and show that the A-type Plexins are differentially expressed in different cranial NCC streams. Conclusions: Our analyses identify a large number of genes differentially regulated between cranial NCCs arising at different axial levels. This data provides a comprehensive description of the genetic landscape driving diversity of distinct cranial NCC streams and provides novel insight into the regulatory networks controlling the formation of specific skeletal elements and the mechanisms promoting migration along different paths.Rachael Lumb, Sam Buckberry, Genevieve Secker, David Lawrence and Quenten Schwar
DC-conductivity of a suspension of insulating particles with internal rotation
We analyse the consequences of Quincke rotation on the conductivity of a
suspension. Quincke rotation refers to the spontaneous rotation of insulating
particles dispersed in a slightly conducting liquid and subject to a high DC
electric field: above a critical field, each particle rotates continuously
around itself with an axis pointing in any direction perpendicular to the DC
field. When the suspension is subject to an electric field lower than the
threshold one, the presence of insulating particles in the host liquid
decreases the bulk conductivity since the particles form obstacles to ion
migration. But for electric fields higher than the critical one, the particles
rotate and facilitate ion migration: the effective conductivity of the
suspension is increased. We provide a theoretical analysis of the impact of
Quincke rotation on the apparent conductivity of a suspension and we present
experimental results obtained with a suspension of PMMA particles dispersed in
weakly conducting liquids
GPCRTree: online hierarchical classification of GPCR function
Background: G protein-coupled receptors (GPCRs) play important physiological roles transducing extracellular signals into intracellular responses. Approximately 50% of all marketed drugs target a GPCR. There remains considerable interest in effectively predicting the function of a GPCR from its primary sequence. Findings: Using techniques drawn from data mining and proteochemometrics, an alignment-free approach to GPCR classification has been devised. It uses a simple representation of a protein's physical properties. GPCRTree, a publicly-available internet server, implements an algorithm that classifies GPCRs at the class, sub-family and sub-subfamily level. Conclusion: A selective top-down classifier was developed which assigns sequences within a GPCR hierarchy. Compared to other publicly available GPCR prediction servers, GPCRTree is considerably more accurate at every level of classification. The server has been available online since March 2008 at URL: http://igrid-ext.cryst.bbk.ac.uk/gpcrtree
Prospects of reaching the quantum regime in Li-Yb mixtures
We perform numerical simulations of trapped Yb ions that are
buffer gas cooled by a cold cloud of Li atoms. This species combination has
been suggested to be the most promising for reaching the quantum regime of
interacting atoms and ions in a Paul trap. Treating the atoms and ions
classically, we compute that the collision energy indeed reaches below the
quantum limit for a perfect linear Paul trap. We analyze the effect of
imperfections in the ion trap that cause excess micromotion. We find that the
suppression of excess micromotion required to reach the quantum limit should be
within experimental reach. Indeed, although the requirements are strong, they
are not excessive and lie within reported values in the literature. We analyze
the detection and suppression of excess micromotion in our experimental setup.
Using the obtained experimental parameters in our simulation, we calculate
collision energies that are a factor 2-11 larger than the quantum limit,
indicating that improvements in micromotion detection and compensation are
needed there. We also analyze the buffer-gas cooling of linear and
two-dimensional ion crystals. We find that the energy stored in the eigenmodes
of ion motion may reach 10-100 K after buffer-gas cooling under realistic
experimental circumstances. Interestingly, not all eigenmodes are buffer-gas
cooled to the same energy. Our results show that with modest improvements of
our experiment, studying atom-ion mixtures in the quantum regime is in reach,
allowing for buffer-gas cooling of the trapped ion quantum platform and to
study the occurrence of atom-ion Feshbach resonances.Comment: 39 pages, 22 figure
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