Tensionless structure of glassy phase

We study a class of homogeneous finite-dimensional Ising models which were recently shown to exhibit glassy properties. Monte Carlo simulations of a particular three-dimensional model in this class show that the glassy phase obtained under slow cooling is dominated by large scale excitations whose energy $E_l$ scales with their size $l$ as $E_l\sim l^{\Theta}$ with $\Theta\sim 1.33(5)$. Simulations suggest that in another model of this class, namely the four-spin model, energy is concentrated mainly in linear defects making also in this case domain walls tensionless. Two-dimensinal variants of these models are trivial and energy of excitations scales with the exponent $\Theta=1.05(5)$.Comment: 5 page

Surgery for lateral elbow pain

Background Surgery is sometimes recommended for persistent lateral elbow pain where other less invasive interventions have failed. Objectives To determine the benefits and safety of surgery for lateral elbow pain. Search strategy We searched CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CINAHL and Web of Science unrestricted by date or language (to 15 December 2010). Selection criteria Randomised and controlled clinical trials assessing a surgical intervention compared with no treatment or another intervention including an alternate surgical intervention, in adults with lateral elbow pain. Data collection and analysis Two authors independently selected trials for inclusion, assessed risk of bias and extracted data. Main results We included five trials involving 191 participants with persistent symptoms of at least five months duration and failed conservative treatment. Three trials compared two different surgical procedures and two trials compared surgery to a non-surgical treatment. All trials were highly susceptible to bias. Meta-analysis was precluded due to differing comparator groups and outcome measures. One trial (24 participants) reported no difference between open extensor carpi radialis brevis (ECRB) surgery and radiofrequency microtenotomy, although reanalysis found that pain was significantly lower in the latter group at three weeks (MD-2.80 points on 10 point scale, 95% CI-5.07 to -0.53). One trial (26 participants) reported no difference between open ECRB surgery and decompression of the posterior interosseous nerve in terms of the number of participants with improvement in pain pain on activity, or tenderness on palpation after an average of 31 months following surgery. One trial (45 participants) found that compared with open release of the ERCB muscle, percutaneous release resulted in slightly better function. One trial (40 participants) found comparable results between open surgical release of the ECRB and botulinum toxin injection at two years, although we could not extract any data for this review. One trial (56 participants) found that extracorporeal shock wave therapy (ESWT) improved pain at night compared with percutaneous tenotomy at 12 months (MD 5 points on 100 point VAS, 95% CI 1.12 to 8.88), but there were no differences in pain at rest or pain on applying pressure. Authors' conclusions Due to a small number of studies, large heterogeneity in interventions across trials, small sample sizes and poor reporting of outcomes, there was insufficient evidence to support or refute the effectiveness of surgery for lateral elbow pain. Further well-designed randomised controlled trials and development of standard outcome measures are needed.Public Health and primary car

Crystallization of a supercooled liquid and of a glass - Ising model approach

Using Monte Carlo simulations we study crystallization in the three-dimensional Ising model with four-spin interaction. We monitor the morphology of crystals which grow after placing crystallization seeds in a supercooled liquid. Defects in such crystals constitute an intricate and very stable network which separate various domains by tensionless domain walls. We also show that the crystallization which occurs during the continuous heating of the glassy phase takes place at a heating-rate dependent temperature.Comment: 7 page

Slow dynamics in the 3--D gonihedric model

We study dynamical aspects of three--dimensional gonihedric spins by using Monte--Carlo methods. The interest of this family of models (parametrized by one self-avoidance parameter $\kappa$) lies in their capability to show remarkably slow dynamics and seemingly glassy behaviour below a certain temperature $T_g$ without the need of introducing disorder of any kind. We consider first a hamiltonian that takes into account only a four--spin term ($\kappa=0$), where a first order phase transition is well established. By studying the relaxation properties at low temperatures we confirm that the model exhibits two distinct regimes. For $T_g< T < T_c$, with long lived metastability and a supercooled phase, the approach to equilibrium is well described by a stretched exponential. For $T<T_g$ the dynamics appears to be logarithmic. We provide an accurate determination of $T_g$. We also determine the evolution of particularly long lived configurations. Next, we consider the case $\kappa=1$, where the plaquette term is absent and the gonihedric action consists in a ferromagnetic Ising with fine-tuned next-to-nearest neighbour interactions. This model exhibits a second order phase transition. The consideration of the relaxation time for configurations in the cold phase reveals the presence of slow dynamics and glassy behaviour for any $T< T_c$. Type II aging features are exhibited by this model.Comment: 13 pages, 12 figure

Sr2V3O9 and Ba2V3O9: quasi one-dimensional spin-systems with an anomalous low temperature susceptibility

The magnetic behaviour of the low-dimensional Vanadium-oxides Sr2V3O9 and Ba2V3O9 was investigated by means of magnetic susceptibility and specific heat measurements. In both compounds, the results can be very well described by an S=1/2 Heisenberg antiferromagnetic chain with an intrachain exchange of J = 82 K and J = 94 K in Sr2V3O9 and Ba2V3O9, respectively. In Sr2V3O9, antiferromagnetic ordering at T_N = 5.3 K indicate a weak interchain exchange of the order of J_perp ~ 2 K. In contrast, no evidence for magnetic order was found in Ba2V3O9 down to 0.5 K, pointing to an even smaller interchain coupling. In both compounds, we observe a pronounced Curie-like increase of the susceptibility below 30 K, which we tentatively attribute to a staggered field effect induced by the applied magnetic field. Results of LDA calculations support the quasi one-dimensional character and indicate that in Sr2V3O9, the magnetic chain is perpendicular to the structural one with the magnetic exchange being transferred through VO4 tetrahedra.Comment: Submitted to Phy. Rev.

Australian recommendations on perioperative use of disease-modifying anti-rheumatic drugs in people with inflammatory arthritis undergoing elective surgery.

OnlinePublDisease-modifying antirheumatic drugs (DMARDs) are effective treatments for inflammatory arthritis but carry an increased risk of infection. For patients undergoing surgery there is a need to consider the trade-off between a theoretical increased risk of infection with continuation of DMARDs perioperatively versus an increased risk of disease flare if they are temporarily withheld. We used GRADE methodology to develop recommendations for perioperative use of DMARDs for people with inflammatory arthritis undergoing elective surgery. The recommendations form part of the NHMRC-endorsed Australian Living Guideline for the Pharmacological Management of Inflammatory Arthritis. Conditional recommendations were made against routinely discontinuing conventional synthetic (cs) and biologic (b) DMARDs in the perioperative period but to consider temporary discontinuation of bDMARDs in individuals with a high risk of infection or where the impact of infection would be severe. A conditional recommendation was made in favour of temporary discontinuation of targeted synthetic (ts) DMARDs in the perioperative period.Rachelle Buchbinder, Vanessa Glennon, Renea V. Johnston, Sue E. Brennan, Chris Fong, Suzie Edward May, Sean O, Neill, Peter Smitham, Lyndal Trevena, Glen Whittaker, Anita Wluka, and Samuel L. Whittl

On gravitational waves emitted by an ensemble of rotating neutron stars

We study the possibility to detect the gravitational wave background generated by all the neutron stars in the Galaxy with only one gravitational wave interferometric detector. The proposed strategy consists in squaring the detector's output and searching for a sidereal modulation. The shape of the squared signal is computed for a disk and a halo distribution of neutron stars. The required noise stability of the interferometric detector is discussed. We argue that a possible population of old neutron stars, originating from a high stellar formation rate at the birth of the Galaxy and not emitting as radio pulsars, could be detected by the proposed technique in the low frequency range of interferometric experiments.Comment: 14 pages, 2 PostScript figures, RevTeX, accepted for publication in Physical Review

Leveraging agriculture for nutrition in South Asia: What do we know, and what have we learned?

Despite significant improvements over recent decades, rates of undernutrition remain high in South Asia, with adverse impacts on morbidity and mortality. Overweight/obesity, among children and adults, is now an additional and major public health concern. While agriculture has the potential to improve nutrition through several pathways, this potential is currently not being realised in the region. The Leveraging Agriculture for Nutrition in South Asia (LANSA) research consortium (2012–2018) set out to improve understanding about how agriculture and related food policies and programs in South Asia (specifically in India, Bangladesh, Pakistan and Afghanistan) can be better conceptualised and implemented in order to enhance impacts on nutrition outcomes, especially those of young children and adolescent girls. This paper provides a snapshot of the agriculture-nutrition nexus in the region, outlines the pathways through which agriculture can influence nutrition outcomes, elaborates on the objectives of the LANSA research consortium within this context, and highlights the core findings of the six papers that form the body of this Special Issue. The paper ends with five key lessons that have emerged from this research, during this decade

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo