178 research outputs found
Full Aging in Spin Glasses
The discovery of memory effects in the magnetization decays of spin glasses
in 1983 began a large effort to determine the exact nature of the decay. While
qualitative arguments have suggested that the decay functions should scale as
, the only time scale in the system, this type of scaling has not yet
been observed. In this letter we report strong evidence for the scaling of the
TRM magnetization decays as a function of . By varying the rate and the
profile that the sample is cooled through its transition temperature to the
measuring temperature, we find that the cooling plays a major role in
determining scaling. As the effective cooling time decreases, scaling improves and for we find almost perfect
scaling. We also find that subtraction of a stationary term
from the magnetization decay has a small effect on the scaling but changes the
form of the magnetization decay and improves overlap between curves produced
with different .Comment: 4 pages, 3 figure
Intermittent quakes and record dynamics in the thermoremanent magnetization of a spin-glass
A novel method for analyzing the intermittent behavior of linear response
data in aging systems is presented and applied to spin-glass thermoremanent
magnetization (TRM) (Rodriguez et al. Phys. Rev. Lett. 91, 037203, 2003).
The probability density function (PDF) of magnetic fluctuations is shown to
have an asymmetric exponential tail, demonstrating that the demagnetization
process is carried by intermittent, significant, spin rearrangements or
\emph{quakes}. These quakes are most pronounced shortly after the field
removal, and in the non-equilibrium aging regime .
For a broad temperature range, we study the dependence of the TRM decay rate on
, the time since the initial quench and on , the time at which the
magnetic field is cut. The and dependence of the rate is extracted
numerically from the data and described analytically using the assumption that
the linear response is subordinated to the intermittent process which
spasmodically release the initial imbalances created by the quench.Comment: 8 pages, 9 figures. The paper has been expanded and restructured, the
figures have been enlarged and improved. Final version, to appear in Phy.
Rev.
The potential for using a Universal Medication Schedule (UMS) to improve adherence in patients taking multiple medications in the UK: a qualitative evaluation
BACKGROUND: Poor adherence to prescribed medication has major consequences. Managing multiple long-term conditions often involves polypharmacy, potentially increasing complexity and the possibility of poor adherence. As a result of the globally recognised problems in supporting adherence to medication, some researchers have proposed the use of reminder charts. The main aim of the research was to explore the need for and perceptions around the 'Universal Medication Schedule' (UMS). Looking at ways in which pharmacists and General Practitioners (GPs) could use the UMS in NHS settings. METHODS: Semi-structured interviews were carried out with 10 GPs, 10 community pharmacists and 15 patients. Patients were aged 65Â years and over, had multiple long-term conditions and were prescribed at least 5 medications. Interviews were recorded and transcribed and thematic analysis was conducted, using a framework approach to manage the data. RESULTS: Attitudes towards the UMS were mixed with stakeholders seeing benefits and limitations to the chart. Practitioners proposed a number of existing services where they thought the UMS could easily be integrated but there was evidence of role conflict with GPs feeling it may be best placed with pharmacists and vice versa. The potential for the UMS to be used as a tool to aid communication between the different services involved in a patient's care was a key theme. CONCLUSIONS: The UMS chart provides consolidated medicines information that might help to improve patients' knowledge and health literacy, which may or may not improve adherence but could help patients in making informed decisions about their treatment. One of the key benefits of using the UMS in practice is that it could be introduced across services. In this way it may aid in medicines reconciliation between healthcare settings to ensure continuity of message, improve patient experience and create more joined up working between services. Further research is needed to test implementation in different services and to assess outcomes on patient understanding and adherence
From Linear to Nonlinear Response in Spin Glasses: Importance of Mean-Field-Theory Predictions
Deviations from spin-glass linear response in a single crystal Cu:Mn 1.5 at %
are studied for a wide range of changes in magnetic field, . Three
quantities, the difference , the effective waiting time,
, and the difference are examined in our
analysis. Three regimes of spin-glass behavior are observed as
increases. Lines in the plane, corresponding to ``weak'' and
``strong'' violations of linear response under a change in magnetic field, are
shown to have the same functional form as the de Almeida-Thouless critical
line. Our results demonstrate the existence of a fundamental link between
static and dynamic properties of spin glasses, predicted by the mean-field
theory of aging phenomena.Comment: 9 pages, 10 figure
Extraction of the Spin Glass Correlation Length
The peak of the spin glass relaxation rate, S(t)=d{-M_{TRM}(t,t_w)}/H/{d ln
t}, is directly related to the typical value of the free energy barrier which
can be explored over experimental time scales. A change in magnetic field H
generates an energy E_z={N_s}{X_fc}{H^2} by which the barrier heights are
reduced, where X_{fc} is the field cooled susceptibility per spin, and N_s is
the number of correlated spins. The shift of the peak of S(t) gives E_z,
generating the correlation length, Ksi(t,T), for Cu:Mn 6at.% and
CdCr_{1.7}In_{0.3}S_4. Fits to power law dynamics, Ksi(t,T)\propto
{t}^{\alpha(T)} and activated dynamics Ksi(t,T) \propto {ln t}^{1/psi} compare
well with simulation fits, but possess too small a prefactor for activated
dynamics.Comment: 4 pages, 4 figures. Department of Physics, University of California,
Riverside, California, and Service de Physique de l'Etat Condense, CEA
Saclay, Gif sur Yvette, France. To appear in Phys. Rev. Lett. January 4, 199
Ordering in a spin glass under applied magnetic field
Torque, torque relaxation, and magnetization measurements on a AuFe spin
glass sample are reported. The experiments carried out up to 7 T show a
transverse irreversibility line in the (H,T) plane up to high applied fields,
and a distinct strong longitudinal irreversibility line at lower fields. The
data demonstrate for that this type of sample, a Heisenberg spin glass with
moderately strong anisotropy, the spin glass ordered state survives under high
applied fields in contrast to predictions of certain "droplet" type scaling
models. The overall phase diagram closely ressembles those of mean field or
chiral models, which both have replica symmetry breaking transitions.Comment: 4 pages, 3 figures, accepted for PR
The Lingual Process of the Sphenoid Bone and the Petrolingual Ligament: Surgical Anatomy, Landmarks, and Clinical Relevance
BACKGROUND:The lingual process of the sphenoid bone (LP) and the petrolingual ligament (PLL) surround laterally the internal carotid artery within the middle cranial fossa (MCF).OBJECTIVE:To study the LP and the PLL and anatomical variations considering their relationships with different structures and landmarks within the MCF, especially oriented toward the endoscopic endonasal approaches.METHODS:Seventy-two sides of dry skulls and 20 sides of embalmed specimens were studied. The measurements of the LP and the PLL were obtained, considering important landmarks in the MCF.RESULTS:The LP had a mean length and height of 5 mm and 3 mm, respectively. Its distance from the foramen lacerum was 6 mm, from the foramen ovale 10 mm, foramen rotundum 15 mm, and petrous apex 9 mm. In 44 sides (61.11%), the LP partially closed the lateral aspect of the carotid sulcus; in 17 sides (23.61%), it was found as a near-ring; and in 11 sides (15.2%), it was considered rudimentary. Considering the PLL, its length and height were, respectively, 9 mm, and 4 mm.CONCLUSION:The LP and PLL separate the carotid artery at the inferior aspect of Meckel's cave and constitute important landmarks for endoscopic endonasal approaches to Meckel's cave and MCF, and their identification and removal is essential for internal carotid artery mobilization in this area
Static chaos and scaling behaviour in the spin-glass phase
We discuss the problem of static chaos in spin glasses. In the case of
magnetic field perturbations, we propose a scaling theory for the spin-glass
phase. Using the mean-field approach we argue that some pure states are
suppressed by the magnetic field and their free energy cost is determined by
the finite-temperature fixed point exponents. In this framework, numerical
results suggest that mean-field chaos exponents are probably exact in finite
dimensions. If we use the droplet approach, numerical results suggest that the
zero-temperature fixed point exponent is very close to
. In both approaches is the lower critical dimension in
agreement with recent numerical simulations.Comment: 28 pages + 6 figures, LateX, figures uuencoded at the end of fil
Supporting people with type 2 diabetes in effective use of their medicine through mobile health technology integrated with clinical care (SuMMiT-D Feasibility): a randomised feasibility trial protocol
Introduction: Type 2 diabetes is common, affecting over 400 million people worldwide. Risk of serious complications can be reduced through use of effective treatments and active self-management. However, people are often concerned about starting new medicines and face difficulties in taking them regularly. Use of brief messages to provide education and support self-management, delivered through mobile phone-based text-messages can be an effective tool for some long-term conditions. We have developed messages aiming to support patients’ self-management of type 2 diabetes in the use of medications and other aspects of self-management, underpinned by theory and evidence. The aim of this trial is to determine the feasibility of a large-scale clinical trial to test the effectiveness and cost-effectiveness of the intervention, compared to usual care.
Methods and analysis: The feasibility trial will be a multi-centre individually randomised, controlled trial in primary care recruiting adults (≥35 years) with type 2 diabetes in England. Consenting participants will be randomised to receive short text-messages three times a week with messages designed to produce change in medication adherence or non-health related messages for six months. The aims are to test recruitment methods, retention to the study, the feasibility of data collection and the mobile-phone and web-based processes of a proposed definitive trial and to refine the text messaging intervention. The primary outcome is the rate of recruitment to randomisation of participants to the trial. Data, including patient reported measures, will be collected online at baseline and the end of the six-month follow-up period. With 200 participants (100 in each group), this trial is powered to estimate 80% follow up within 95% confidence intervals of 73.8% to 85.3%. The analysis will follow a pre-specified plan.
Ethics and Dissemination: Ethics approval was obtained from the West of Scotland Research Ethics Committee 05. The results will be disseminated through conference presentations, peer-reviewed journals and will be published on the trial website: www.summit-d.org.</p
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