Hahn echo and criticality in spin-chain systems

We establish a relation between Hahn spin-echo of a spin-$\frac 1 2$ particle and quantum phase transition in a spin-chain, which couples to the particle. The Hahn echo is calculated and discussed at zero as well as at finite temperatures. On the example of XY model, we show that the critical points of the chain are marked by the extremal values in the Hahn echo, and influence the Hahn echo in surprising high temperature. An explanation for the relation between the echo and criticality is also presented.Comment: 5 pages, 6 figure

Reconciliation of experimental and theoretical electric tensor polarizabilities of the cesium ground state

We present a new theoretical analysis of the strongly suppressed F- and M-dependent Stark shifts of the Cs ground state hyperfine structure. Our treatment uses third order perturbation theory including off-diagonal hyperfine interactions not considered in earlier treatments. A numerical evaluation of the perturbation sum using bound states up to n=200 yields ground state tensor polarizabilities which are in good agreement with experimental values, thereby bridging the 40-year-old gap between experiments and theory. We have further found that the tensor polarizabilities of the two ground state hyperfine manifolds have opposite signs, in disagreement with an earlier derivation. This sign error has a direct implication for the precise evaluation of the blackbody radiation shift in primary frequency standards.Comment: 7 pages, 2 figures, accepted for publication in Europhysics Letter

Enhanced grain surface effect on magnetic properties of nanometric La0.7Ca0.3MnO3 manganite : Evidence of surface spin freezing of manganite nanoparticles

We have investigated the effect of nanometric grain size on magnetic properties of single phase, nanocrystalline, granular La0.7Ca0.3MnO3 (LCMO) sample. We have considered core-shell structure of our LCMO nanoparticles, which can explain its magnetic properties. From the temperature dependence of field cooled (FC) and zero-field cooled (ZFC) dc magnetization (DCM), the magnetic properties could be distinguished into two regimes: a relatively high temperature regime T > 40 K where the broad maximum of ZFC curve (at T = Tmax) is associated with the blocking of core particle moments, whereas the sharp maximum (at T = TS) is related to the freezing of surface (shell) spins. The unusual shape of M (H) loop at T = 1.5 K, temperature dependent feature of coercive field and remanent magnetization give a strong support of surface spin freezing that are occurring at lower temperature regime (T < 40 K) in this LCMO nanoparticles. Additionally, waiting time (tw) dependence of ZFC relaxation measurements at T = 50 K show weak dependence of relaxation rate [S(t)] on tw and dM/dln(t) following a logarithmic variation on time. Both of these features strongly support the high temperature regime to be associated with the blocking of core moments. At T = 20 K, ZFC relaxation measurements indicates the existence of two different types of relaxation processes in the sample with S(t) attaining a maximum at the elapsed time very close to the wait time tw = 1000 sec, which is an unequivocal sign of glassy behavior. This age-dependent effect convincingly establish the surface spin freezing of our LCMO nanoparticles associated with a background of superparamagnetic (SPM) phase of core moments.Comment: 41 pages, 10 figure

A Bayesian spatio-temporal model of panel design data: airborne particle number concentration in Brisbane, Australia

This paper outlines a methodology for semi-parametric spatio-temporal modelling of data which is dense in time but sparse in space, obtained from a split panel design, the most feasible approach to covering space and time with limited equipment. The data are hourly averaged particle number concentration (PNC) and were collected, as part of the Ultrafine Particles from Transport Emissions and Child Health (UPTECH) project. Two weeks of continuous measurements were taken at each of a number of government primary schools in the Brisbane Metropolitan Area. The monitoring equipment was taken to each school sequentially. The school data are augmented by data from long term monitoring stations at three locations in Brisbane, Australia. Fitting the model helps describe the spatial and temporal variability at a subset of the UPTECH schools and the long-term monitoring sites. The temporal variation is modelled hierarchically with penalised random walk terms, one common to all sites and a term accounting for the remaining temporal trend at each site. Parameter estimates and their uncertainty are computed in a computationally efficient approximate Bayesian inference environment, R-INLA. The temporal part of the model explains daily and weekly cycles in PNC at the schools, which can be used to estimate the exposure of school children to ultrafine particles (UFPs) emitted by vehicles. At each school and long-term monitoring site, peaks in PNC can be attributed to the morning and afternoon rush hour traffic and new particle formation events. The spatial component of the model describes the school to school variation in mean PNC at each school and within each school ground. It is shown how the spatial model can be expanded to identify spatial patterns at the city scale with the inclusion of more spatial locations.Comment: Draft of this paper presented at ISBA 2012 as poster, part of UPTECH projec

Land Transportation Effects on Manufacture and Regional Economy of Sumatra of Indonesia

The study aimed to determine the effect simultaneously between land transportation and manufacturing industry on economic improvement An explanation research was conducted to obtain the causal relationship between land transportation and manufacture. The data used in this study were off secondary sources and time series data forms from 2006-2015 data from the Central Statistics Agency (BPS) of Labuhan Batu Regency. Regression analysis was applied the mathematical relationship between the output variable or dependent (Y) with one or several input / independent variables (X). The mathematical relationship is used as a regression model that is used to predict or predict the output value (Y) based on a particular input value (X). The results of this study indicated that simultaneously the land transportation variable and manufacturing industry have a positive and significant effect on the economic improvement variable. The results obtained a tcount value of 3.599. Thus tcount is greater than t table (3.241&gt; 1.894); then H0 is rejected HA is accepted, meaning that partially there is a positive and significant influence between land transportation and economic improvement. The results obtained a tcount of 0.112. Thus tcount is greater than t table (0.112 &lt;1.894) then H0 is accepted HA is rejected, meaning that partially there is no positive and significant influence between the manufacturing industry on economic improvement

Effects of Asset Structure, Operating Cash Flow, and Profitability on Debt Policy in Property and Real Estate Companies on the Indonesia Stock Exchange Period 2013-2017

This study aims to determine the effect of asset structure, operating cash flow, and profitability on debt policy in property and real estate companies in the Indonesia Stock Exchange in 2013-2017. The analytical method used is multiple linear regression, F test and t test. The results of the analysis of this study indicate that the structure of assets, operating cash flows, and profitability have a simultaneous effect on debt policy. Meanwhile the analysis partially shows that the asset structure, operating cash flows, and profitability do not partially affect debt policy

Pharmacological effects of raas blockade in ischemic nephropathy

Background: The management of ischemic nephropathy due to atherosclerotic renal artery stenosis has become increasingly conservative in the modern era, with current guidelines recommending optimized medical therapy as the initial step. The doubts raised by the recently published trials of revascularization strategies have led to a renewed focus on pharmacological strategies promoting blood pressure control and renal protection. It is essential to further elucidate the pathophysiological mechanisms underlying hypoperfusion induced renal microvascular dysfunction with subsequent tissue injury and fibrogenesis. The role of renin angiotensin aldosterone system as a mediator of the main pathophysiological consequences of ischemic nephropathy is well known. However, more recent experimental evidence on the adrenergic system and intrarenal tubular feedback mechanisms has stimulated new interest towards a multi-target therapeutic approach. Methods: This review focuses on the pharmacology of the principle therapeutic drug classes currently used in the treatment of atherosclerotic renal artery stenosis with an analysis of their metabolic aspects and use in clinical practice based on evidence from clinical trials. Results and Conclusions: An optimal pharmacologic approach is crucial for a successful prevention of renal injury and cardiovascular events in this high-risk population. Antihypertensive treatment should include renin angiotensin aldosterone system blockade medication not only for their antihypertensive properties, but especially for those cardio and renoprotectiv

The effects of contract detail and prior ties on contract change : a learning perspective

Despite the large literature on alliance contract design, we know little about how transacting parties change and amend their underlying contracts during the execution of strategic alliances. Drawing on existing research in the alliance contracting literature, we develop the empirical question of how contract detail and prior ties influence the amount, direction, and type of change in such agreements during the collaboration. We generated a sample of 115 joint ventures (JVs) by distributing a survey to JV board members or top managers and found that the amount of contract change is negatively associated with the level of detail in the initial contract but is positively associated with the number of prior ties between alliance partners. In relation to the direction of contract change, we find that the level of detail of the initial agreements negatively correlates with the likelihood of removing or weakening existing provisions and that prior collaborative experience positively correlates with the likelihood of strengthening of existing provisions or adding of new ones. We also find that prior ties affect the type of change in that JV parents prefer to change enforcement provisions more so than the coordination provisions in the contract. Our paper generates new insights on the complementarities between relational governance and transaction cost economics perspectives on alliance contracting

Effects of Mitomycin C in Early Conjunctival Inflammation after Pterygium Surgery

Purpose: The purpose of this study was to compare inflammatory events and graft characteristics 1 month and 6 months after conjunctival limbal autograft (CLAU) with and without intraoperative mitomycin C (MMC). Methods: This study included 69 eyes of 69 patient’s eyes with pterygium. Clinical data concerning patient demography, preoperative examination including pterygium morphology, recurrence clinical assessment, and complications after CLAU with (MMC+) and without (MMC-) intraoperative MMC were all registered at 1 month and 6 months after surgery. Results: Thirty-five eyes were included in MMC+ and 34 in MMC-. Preoperative data were similar in both groups (Student’s t test and Fisher’s exact test; p > 0.05). Thirty-four (49.6%) eyes in the whole sample showed at least one inflammatory complication at 1 month after surgery. MMC- group showed a significantly higher number of cases with complications (p 0.05; Chi2 test). Pyogenic granuloma developed at the surgical site in three eyes (4.37%), two of those granulomas were at the MMC- group (p > 0.05). Tendency for recurrences was significantly different between both groups (p = 0.0001; Fisher’s exact test) at the end of 6 months. Thirteen (38%) eyes showed recurrence in MMC- and no cases were displayed in MMC+. Presence of at least 1 inflammatory event was only seen in 16 (23%) cases, all of them in MMC-. Specifically, 15 (44%) eyes showed hyperemia and one (3%) eye presented conjunctival hemorrhages. No new cases of pyogenic granuloma or graft contraction were seen at this time point in both groups. Hyperemia was the only specific event with significant differences between MMC- and MMC+ (p = 0.0001; Fisher’s exact test) at 6 months after surgery. Conclusion: The eyes receiving intraoperative MMC after CLAU seem to present less hyperemia and graft contraction after surgery than those that did not receive MMC as an adjuvant factor. Intraoperative MMC could be associated with a lower recurrence rates.Postprint (author's final draft

Effects of Pouring Temperature on Solidification Using Energy Profile Analysis on Aluminum Alloy

This work covered the study of energy profiles as influenced by solidification on sand cast 6063 aluminum alloy. Temperature is an important parameter, most especially in foundry technology that influences properties and morphology of cast products. Different pouring temperatures of 680oC, 740oC and 780oC were considered. Mechanical energy expended and the quantity of heat evolved was evaluated from results obtained from tensile test experiments carried on the three samples. Relationship between change in coefficient of thermal expansion and change in applied tensile load were derived; it was observed that the maximum energy expended before fracture for samples decreased with increasing pouring temperature. Increasing pouring temperature decreased the amount of energy to be expended during deformation. This also influenced the change in heat evolved per time