Calculation of Densities of States and Spectral Functions by Chebyshev Recursion and Maximum Entropy

We present an efficient algorithm for calculating spectral properties of large sparse Hamiltonian matrices such as densities of states and spectral functions. The combination of Chebyshev recursion and maximum entropy achieves high energy resolution without significant roundoff error, machine precision or numerical instability limitations. If controlled statistical or systematic errors are acceptable, cpu and memory requirements scale linearly in the number of states. The inference of spectral properties from moments is much better conditioned for Chebyshev moments than for power moments. We adapt concepts from the kernel polynomial approximation, a linear Chebyshev approximation with optimized Gibbs damping, to control the accuracy of Fourier integrals of positive non-analytic functions. We compare the performance of kernel polynomial and maximum entropy algorithms for an electronic structure example.Comment: 8 pages RevTex, 3 postscript figure

Heart failure following cancer treatment: characteristics, survival and mortality of a linked health data analysis

Background: Cardiotoxicity resulting in heart failure is a devastating complication of cancer therapy. A patient may survive cancer only to develop heart failure (HF), which has a higher mortality rate than some cancers. Aim: This study aimed to describe the characteristics and outcomes of HF in patients with blood or breast cancer after chemotherapy treatment. Methods: Queensland Cancer Registry, Death Registry and Hospital Administration records were linked (1996–2009). Patients were categorised as those with an index HF admission (that occurred after cancer diagnosis) and those without an index HF admission (non-HF). Results: A total of 15 987 patients was included, and 1062 (6.6%) had an index HF admission. Median age of HF patients was 67 years (interquartile range 58–75) versus 54 years (interquartile range 44–64) for non-HF patients. More men than women developed HF (48.6% vs 29.5%), and a greater proportion in the HF group had haematological cancer (83.1%) compared with breast cancer (16.9%). After covariate adjustment, HF patients had increased mortality risk compared with non-HF patients (hazard ratios 1.67 (95% confidence interval, 1.54–1.81)), and 47% of the index HF admission occurred within 1 year from cancer diagnosis and 70% within 3 years. Conclusion: Cancer treatment may place patients at a greater risk of developing HF. The onset of HF occurred soon after chemotherapy, and those who developed HF had a greater mortality risk

Conformational changes of calmodulin upon Ca2+ binding studied with a microfluidic mixer

A microfluidic mixer is applied to study the kinetics of calmodulin conformational changes upon Ca2+ binding. The device facilitates rapid, uniform mixing by decoupling hydrodynamic focusing from diffusive mixing and accesses time scales of tens of microseconds. The mixer is used in conjunction with multiphoton microscopy to examine the fast Ca2+-induced transitions of acrylodan-labeled calmodulin. We find that the kinetic rates of the conformational changes in two homologous globular domains differ by more than an order of magnitude. The characteristic time constants are ≈490 μs for the transitions in the C-terminal domain and ≈20 ms for those in the N-terminal domain of the protein. We discuss possible mechanisms for the two distinct events and the biological role of the stable intermediate, half-saturated calmodulin

Cancer survival for Aboriginal and Torres Strait Islander Australians: a national study of survival rates and excess mortality

BackgroundNational cancer survival statistics are available for the total Australian population but not Indigenous Australians, although their cancer mortality rates are known to be higher than those of other Australians. We aimed to validate analysis methods and report cancer survival rates for Indigenous Australians as the basis for regular national reporting.MethodsWe used national cancer registrations data to calculate all-cancer and site-specific relative survival for Indigenous Australians (compared with non-Indigenous Australians) diagnosed in 2001-2005. Because of limited availability of Indigenous life tables, we validated and used cause-specific survival (rather than relative survival) for proportional hazards regression to analyze time trends and regional variation in all-cancer survival between 1991 and 2005.ResultsSurvival was lower for Indigenous than non-Indigenous Australians for all cancers combined and for many cancer sites. The excess mortality of Indigenous people with cancer was restricted to the first three years after diagnosis, and greatest in the first year. Survival was lower for rural and remote than urban residents; this disparity was much greater for Indigenous people. Survival improved between 1991 and 2005 for non-Indigenous people (mortality decreased by 28%), but to a much lesser extent for Indigenous people (11%) and only for those in remote areas; cancer survival did not improve for urban Indigenous residents.ConclusionsCancer survival is lower for Indigenous than other Australians, for all cancers combined and many individual cancer sites, although more accurate recording of Indigenous status by cancer registers is required before the extent of this disadvantage can be known with certainty. Cancer care for Indigenous Australians needs to be considerably improved; cancer diagnosis, treatment, and support services need to be redesigned specifically to be accessible and acceptable to Indigenous people

Evidence for softening of first-order transition in 3D by quenched disorder

We study by extensive Monte Carlo simulations the effect of random bond dilution on the phase transition of the three-dimensional 4-state Potts model which is known to exhibit a strong first-order transition in the pure case. The phase diagram in the dilution-temperature plane is determined from the peaks of the susceptibility for sufficiently large system sizes. In the strongly disordered regime, numerical evidence for softening to a second-order transition induced by randomness is given. Here a large-scale finite-size scaling analysis, made difficult due to strong crossover effects presumably caused by the percolation fixed point, is performed.Comment: LaTeX file with Revtex, 4 pages, 4 eps figure

Sociodemographic disparities in survival from colorectal cancer in South Australia: a population-wide data linkage study

Copyright © Beckmann et al. 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Inequalities in survival from colorectal cancer (CRC) across socioeconomic groups and by area of residence have been described in various health care settings. Few population-wide datasets which include clinical and treatment information are available in Australia to investigate disparities. This study examines socio-demographic differences in survival for CRC patients in South Australia (SA), using a population-wide database derived via linkage of administrative and surveillance datasets. Methods: The study population comprised all cases of CRC diagnosed in 2003-2008 among SA residents aged 50-79 yrs in the SA Central Cancer Registry. Measures of socioeconomic status (area level), geographical remoteness, clinical characteristics, comorbid conditions, treatments and outcomes were derived through record linkage of central cancer registry, hospital-based clinical registries, hospital separations, and radiotherapy services data sources. Socio-demographic disparities in CRC survival were examined using competing risk regression analysis. Results: Four thousand six hundred and forty one eligible cases were followed for an average of 4.7 yrs, during which time 1525 died from CRC and 416 died from other causes. Results of competing risk regression indicated higher risk of CRC death with higher grade (HR high v low =2.25, 95 % CI 1.32-3.84), later stage (HR C v A = 7.74, 95 % CI 5.75-10.4), severe comorbidity (HR severe v none =1.21, 95 % CI 1.02-1.44) and receiving radiotherapy (HR = 1.41, 95 % CI 1.18-1.68). Patients from the most socioeconomically advantaged areas had significantly better outcomes than those from the least advantaged areas (HR =0.75, 95 % 0.62-0.91). Patients residing in remote locations had significantly worse outcomes than metropolitan residents, though this was only evident for stages A-C (HR = 1.35, 95 % CI 1.01-1.80). These disparities were not explained by differences in stage at diagnosis between socioeconomic groups or area of residence. Nor were they explained by differences in patient factors, other tumour characteristics, comorbidity, or treatment modalities. Conclusions: Socio-economic and regional disparities in survival following CRC are evident in SA, despite having a universal health care system. Of particular concern is the poorer survival for patients from remote areas with potentially curable CRC. Reasons for thes

Estimation of the charge carrier localization length from Gaussian fluctuations in the magneto-thermopower of La_{0.6}Y_{0.1}Ca_{0.3}MnO_3

The magneto-thermoelectric power (TEP) $\Delta S(T,H)$ of perovskite type manganise oxide $La_{0.6}Y_{0.1}Ca_{0.3}MnO_3$ is found to exhibit a sharp peak at some temperature $T^{*}=170K$. By approximating the true shape of the measured magneto-TEP in the vicinity of $T^{*}$ by a linear triangle of the form $\Delta S(T,H)\simeq S_p(H)\pm B^{\pm}(H)(T^{*}-T)$, we observe that $B ^{-}(H)\simeq 2B ^{+}(H)$. We adopt the electron localization scenario and introduce a Ginzburg-Landau (GL) type theory which incorporates the two concurrent phase transitions, viz., the paramagnetic-ferromagnetic transition at the Curie point $T_C$ and the "metal-insulator" (M-I) transition at $T_{MI}$. The latter is characterized by the divergence of the field-dependent charge carrier localization length $\xi (T,H)$ at some characteristic field $H_0$. Calculating the average and fluctuation contributions to the total magnetization and the transport entropy related magneto-TEP $\Delta S(T,H)$ within the GL theory, we obtain a simple relationship between $T^{*}$ and the above two critical temperatures ($T_{C}$ and $T_{MI}$). The observed slope ratio $B ^{-}(H)/B ^{+}(H)$ is found to be governed by the competition between the electron-spin exchange $JS$ and the induced magnetic energy $M_sH_0$. The comparison of our data with the model predictions produce $T_{C}=195K$, $JS=40meV$, $M_0=0.4M_s$, $\xi_0=10\AA$, and $n_e/n_i=2/3$ for the estimates of the Curie temperature, the exchange coupling constant, the critical magnetization, the localization length, and the free-to-localized carrier number density ratio, respectively.Comment: 6 pages (REVTEX), 2 PS figures (epsf.sty); submitted to Phys.Rev.

NBS monograph

From Introduction: "In the present report, therefore, polynomials representing isotherms and isochores are combined with numerical methods of computation for the purpose of improving accuracy, in particular for the derivatives of the P-p-T surface.

Scalar-field Pressure in Induced Gravity with Higgs Potential and Dark Matter

A model of induced gravity with a Higgs potential is investigated in detail in view of the pressure components related to the scalar-field excitations. The physical consequences emerging as an artifact due to the presence of these pressure terms are analysed in terms of the constraints parting from energy density, solar-relativistic effects and galactic dynamics along with the dark matter halos.Comment: 26 pages, 3 figures, Minor revision, Published in JHE

Instability of metal-insulator transition against thermal cycling in phase separated Cr-doped manganites

We show that metal-insulator transition in Pr0.5Ca0.5Mn1-xCrxO3 (x = 0.015-0.025) is unstable against thermal cycling. Insulator-metal transition shifts down and low temperature resistivity increases each time when the sample is cycled between a starting temperature TS and a final temperature TF. The effect is dramatic lower is x. Insulator-metal transition in x = 0.015 can be completely destroyed by thermal cycling in absence of magnetic field as well as under H = 2 T. Magnetic measurements suggest that ferromagnetic phase fraction decreases with thermal cycling. We suggest that increase in strains in ferromagnetic- charge ordered interface could be a possible origin of the observed effect.Comment: 14 pages, 5 figures and 2 tables (revised