Heterogeneous slow dynamics in a two dimensional doped classical antiferromagnet

We introduce a lattice model for a classical doped two dimensional antiferromagnet which has no quenched disorder, yet displays slow dynamics similar to those observed in supercooled liquids. We calculate two-time spatial and spin correlations via Monte Carlo simulations and find that for sufficiently low temperatures, there is anomalous diffusion and stretched-exponential relaxation of spin correlations. The relaxation times associated with spin correlations and diffusion both diverge at low temperatures in a sub-Arrhenius fashion if the fit is done over a large temperature-window or an Arrhenius fashion if only low temperatures are considered. We find evidence of spatially heterogeneous dynamics, in which vacancies created by changes in occupation facilitate spin flips on neighbouring sites. We find violations of the Stokes-Einstein relation and Debye-Stokes-Einstein relation and show that the probability distributions of local spatial correlations indicate fast and slow populations of sites, and local spin correlations indicate a wide distribution of relaxation times, similar to observ ations in other glassy systems with and without quenched disorder.Comment: 12 pages, 17 figures, corrected erroneous figure, and improved quality of manuscript, updated reference

FitFlame – Health and Fitness Coaching Application to Mitigate the Issues in the Current Applications

Online fitness coaches help people achieve a healthy lifestyle by offering customized solutions. The demand for professional coaching is expected to grow in the coming years. Nevertheless, no applications in the market address the problems in the coaching process. Today, coaches and clients had to use many third-party apps. The reason for this is that no single fitness coaching app offers communication and exercise-tracking features. Even though some apps meet some of these requirements, they are out of reach for most people's budgets. This paper aims to suggest a robust and full-fledged app to mitigate those issues. FitFlame is the name of the proposed app. Both coaches and clients can benefit from this app. Also, FitFlame is a fitness coaching system available on mobile and the web. It helps clients locate and contact coaches, subscribe to coaching plans, and track their progress. It does away with third-party programs and gives users a better experience

Diffusion and viscosity in a supercooled polydisperse system

We have carried out extensive molecular dynamics simulations of a supercooled polydisperse Lennard-Jones liquid with large variations in temperature at a fixed pressure. The particles in the system are considered to be polydisperse both in size and mass. The temperature dependence of the dynamical properties such as the viscosity ($\eta$) and the self-diffusion coefficients ($D_i$) of different size particles is studied. Both viscosity and diffusion coefficients show super-Arrhenius temperature dependence and fit well to the well-known Vogel-Fulcher-Tammann (VFT) equation. Within the temperature range investigated, the value of the Angell's fragility parameter (D $\approx 1.4$) classifies the present system into a strongly fragile liquid. The critical temperature for diffusion ($T_o^{D_i}$) increases with the size of the particles. The critical temperature for viscosity ($T_o^{\eta}$) is larger than that for the diffusion and a sizeable deviations appear for the smaller size particles implying a decoupling of translational diffusion from viscosity in deeply supercooled liquid. Indeed, the diffusion shows markedly non-Stokesian behavior at low temperatures where a highly nonlinear dependence on size is observed. An inspection of the trajectories of the particles shows that at low temperatures the motions of both the smallest and largest size particles are discontinuous (jump-type). However, the crossover from continuous Brownian to large length hopping motion takes place at shorter time scales for the smaller size particles.Comment: Revtex4, 7 pages, 8 figure

FIGO postpartum intrauterine device initiative: Complication rates across six countries.

OBJECTIVE: To record and analyze complication rates following postpartum intrauterine device (PPIUD) insertion in 48 hospitals in six countries: Sri Lanka, India, Nepal, Bangladesh, Tanzania, and Kenya. METHODS: Healthcare providers were trained in counselling and insertion of PPIUD via a training-the-trainer model. Data were collected on methodology, timing, cadre of staff providing care, and number of insertions. Data on complications were collected at 6-week follow-up. Statistical analysis was performed to elucidate factors associated with increased expulsion and absence of threads. RESULTS: From May 2014 to September 2017, 36 766 PPIUDs were inserted: 53% vaginal and 47% at cesarean delivery; 74% were inserted by doctors. Follow-up was attended by 52%. Expulsion and removal rates were 2.5% and 3.6%, respectively. Threads were not visible in 29%. Expulsion was less likely after cesarean insertion (aOR 0.33; 95% CI, 0.26-0.41), following vaginal insertion at between 10 minutes and 48 hours (aOR 0.59; 95% CI, 0.42-0.83), and when insertion was performed by a nurse (aOR 0.33; 95% CI, 0.22-0.50). CONCLUSION: PPIUD has low complication rates and can be safely inserted by a variety of trained health staff. Given the immediate benefit of the one-stop approach, governments should urgently consider adopting this model

The Evolution of PSR J0737-3039B and a Model for Relativistic Spin Precession

We present the evolution of the radio emission from the 2.8-s pulsar of the double pulsar system PSR J0737-3039A/B. We provide an update on the Burgay et al. (2005) analysis by describing the changes in the pulse profile and flux density over five years of observations, culminating in the B pulsar's radio disappearance in 2008 March. Over this time, the flux density decreases by 0.177 mJy/yr at the brightest orbital phases and the pulse profile evolves from a single to a double peak, with a separation rate of 2.6 deg/yr. The pulse profile changes are most likely caused by relativistic spin precession, but can not be easily explained with a circular hollow-cone beam as in the model of Clifton & Weisberg (2008). Relativistic spin precession, coupled with an elliptical beam, can model the pulse profile evolution well. This particular beam shape predicts geometrical parameters for the two bright orbital phases which are consistent and similar to those derived by Breton et al. (2008). However, the observed decrease in flux over time and B's eventual disappearance cannot be easily explained by the model and may be due to the changing influence of A on B.Comment: 20 pages, 18 figures, Accepted by ApJ on 2 August 201

Post-tsunami natural regeneration of coastal vegetation in the Hambantota district in south-eastern Sri Lanka

A qualitative rapid survey was conducted in 45 plots distributed in the gentle seashore vegetation andsand dunes (n = 13), coastal scrublands (n = 19), and mangroves (n = 13) along the coastline ofHambantota District, affected by the Indian Ocean tsunami. The objective of the survey was toinvestigate the natural regeneration of coastal vegetation 20 months after the tsunami disturbance21 plant species belonging to 19 families were recorded as the prominent plants regenerating inaffected mangroves, while 16 species in 15 families and 32 species in 23 families were observed asprom inent plants to regenerate in affected areas of the gentle sea-shore vegetation and coastalscrublands respectively.In tsunami affected mangrove stands Acanthus iltctfolius (in 50% of study plots), Achrosticumaureum (40%) and Lumnitzera racemosa (17%) were the dominant species establishing in openmuddy substrates, while Clerodendrum inerme (57%), Lumnitzera racemosa and Excoecariaaga//ocha (29% each) were regenerating in sand deposited in the mangrove patches.Ipomoea pes-caprae (85%), Scaevola taccada and Calotropis gigantea (23% each) were observedas the dominant species re-establishing in the gentle seashore vegetation, while Spinifex littoreusshows a slow rate of regeneration. Most of the destroyed Pandanus odoratissimus bushes facingthe beach are not regenerating. Instead a new row of Pandanus was observed regenerating immediatelybacking the original stands. Prominent species regenerating in coastal scrublands are Crotonbonplandianus and Gymnema sylvestre (37% each), Clerodendrum inerme (16%), Calotropisgigantea (10%) and Crateva adansonii (10%) and saplings of Azadirachta indica and Limoniaacidissitna .Invasive alien plants, mainly Opuntia dillennii have established well and spreading vigorously inaffected coastal scrublands (58%), some study plots of gentle seashore vegetation (31 %) as wellas on sand depositions in the affected mangroves (15%). This species was observed replacing thespaces occupied by destroyed Pandanus odoratissimus bushes and Spinifex littoreus beds.Invasive alien plants such as Prosopis juliflora and Lantana camara were also spreading intsunami disturbed coastal scrublands.

Force distributions near the jamming and glass transitions

We calculate the distribution of interparticle normal forces $P(F)$ near the glass and jamming transitions in model supercooled liquids and foams, respectively. $P(F)$ develops a peak that appears near the glass or jamming transitions, whose height increases with decreasing temperature, decreasing shear stress and increasing packing density. A similar shape of $P(F)$ was observed in experiments on static granular packings. We propose that the appearance of this peak signals the development of a yield stress. The sensitivity of the peak to temperature, shear stress and density lends credence to the recently proposed generalized jamming phase diagram.Comment: 4 pages, 3 postscript figures;Version 3 replaces figure 1 and removes figure 2 from version 1. Significant rewording of version 1 to emphasize the formation of peak in P(F) when these systems jam along five different routes of the recently proposed jamming phase diagram. Version 2 displayed the incorrect abstrac

Constraining the optical emission from the double pulsar system J0737-3039

We present the first optical observations of the unique system J0737-3039 (composed of two pulsars, hereafter PSR-A and PSR-B). Ultra-deep optical observations, performed with the High Resolution Camera of the Advanced Camera for Surveys on board the Hubble Space Telescope could not detect any optical emission from the system down to m_F435W=27.0 and m_F606W=28.3. The estimated optical flux limits are used to constrain the three-component (two thermal and one non-thermal) model recently proposed to reproduce the XMM-Newton X-ray spectrum. They suggest the presence of a break at low energies in the non-thermal power law component of PSR-A and are compatible with the expected black-body emission from the PSR-B surface. The corresponding efficiency of the optical emission from PSR-A's magnetosphere would be comparable to that of other Myr-old pulsars, thus suggesting that this parameter may not dramatically evolve over a time-scale of a few Myr.Comment: 16 pages, 3 figures, ApJ accepte

Solidity of Viscous Liquids

Recent NMR experiments on supercooled toluene and glycerol by Hinze and Bohmer show that small rotation angles dominate with only few large molecular rotations. These results are here interpreted by assuming that viscous liquids are solid-like on short length scales. A characteristic length, the "solidity length", separates solid-like behavior from liquid-like behavior.Comment: Plain RevTex file, no figure