53,360 research outputs found
Anomalous spin-dependent behaviour of one-dimensional subbands
We report a new electron interaction effect in GaAs/AlGaAs quantum wires.
Using DC-bias spectroscopy, we show that large and abrupt changes occur to the
energies of spin-down (lower energy) states as they populate. The effect is not
observed for spin-up energy states. At B=0, interactions have a pronounced
effect, in the form of the well-known 0.7 Structure. However, our new results
show that interactions strongly affect the energy spectrum at all magnetic
fields, from 0 to 16T, not just in the vicinity of the 0.7 Structure.Comment: 4 pages, 2 figure
A simple stochastic model for the evolution of protein lengths
We analyse a simple discrete-time stochastic process for the theoretical
modeling of the evolution of protein lengths. At every step of the process a
new protein is produced as a modification of one of the proteins already
existing and its length is assumed to be random variable which depends only on
the length of the originating protein. Thus a Random Recursive Trees (RRT) is
produced over the natural integers. If (quasi) scale invariance is assumed, the
length distribution in a single history tends to a lognormal form with a
specific signature of the deviations from exact gaussianity. Comparison with
the very large SIMAP protein database shows good agreement.Comment: 12 pages, 4 figure
Experimental evidence for radiative attachment in astrochemistry from electron attachment to NCCCCN
Electron attachment to NCCCCN, dicyanoacetylene (2-butynedinitrile), has been observed. Metastable parent anions, NCCCCN_â, with microsecond or longer lifetimes are formed close to 0 eV electron energy with a cross section of âĽ0.25 2. The stability of NCCCCN suggests that radiative attachment to NCCCCN and similar _â °A linear carbon chain molecules may be an important mechanism for the formation of negatively charged molecular ions in astrophysical environments. CCCN_ and CN_ fragment anions are formed at âź3 and âź6 eV
Conceptualisations of childrenâs wellbeing at school: the contribution of recognition theory
A large study in Australian schools aimed to elucidate understandings of âwellbeingâ and of factors in school life that contribute to it. Students and teachers understood wellbeing primarily, and holistically, in terms of interpersonal relationships, in contrast to policy documents which mainly focused on âproblem areasâ such as mental health. The study also drew on recognition theory as developed by the social philosopher Axel Honneth. Results indicate that recognition theory may be useful in understanding wellbeing in schools, and that empirical research in schools may give rise to further questions regarding theory
Guidelines for the management of the foot health problems associated with rheumatoid arthritis
Background. Rheumatoid arthritis (RA) as a chronic systemic disease, commonly affects the feet, impacting
negatively on patients' quality of life. Specialist podiatrists have a prime role to play in the assessment and
management of foot and ankle problems within this patient group. However, it has been identified that in many
areas there is no specialist podiatry service, with many patients being managed by nonâspecialist podiatrists.
Therefore, the North West Clinical Effectiveness Group for the Foot in Rheumatic Diseases (NWCEG) identified
the need to develop âpractitioner facingâ guidelines for the management of specific foot health problems associated
with RA.
Methods. Members of a guideline development group from the NWCEG each reviewed the evidence for specific
aspects of the assessment and management of foot problems. Where evidence was lacking, âexpert opinionâ was
obtained from the members of the NWCEG and added as a consensus on current and best practice. An iterative
approach was employed, with the results being reviewed and revised by all members of the group and external
reviewers before the final guideline document was produced.
Results. The management of specific foot problems (callus, nail pathology, ulceration) and the use of specific
interventions (foot orthoses, footwear, patient education, steroid injection therapy) are detailed and standards in
relation to each are provided. A diagrammatic screening pathway is presented, with the aim of guiding nonspecialist
podiatrists through the complexity of assessing and managing those patients with problems requiring
input from a specialist podiatrist and other members of the rheumatology multidisciplinary team.
Conclusion. This pragmatic approach ensured that the guidelines were relevant and applicable to current practice
as âbest practiceâ, based on the available evidence from the literature and consensus expert opinion. These
guidelines provide both specialist and nonâspecialist podiatrists with the essential and âgold standardâ aspects of
managing people with RAârelated foot problems
Systematic derivation of a rotationally covariant extension of the 2-dimensional Newell-Whitehead-Segel equation
An extension of the Newell-Whitehead-Segel amplitude equation covariant under
abritrary rotations is derived systematically by the renormalization group
method.Comment: 8 pages, to appear in Phys. Rev. Letters, March 18, 199
- âŚ