Common-reflection-surface imaging of shallow and ultrashallow reflectors

We analyzed the feasibility of the common-reflection-surface (CRS) stack for near-surface surveys as an alternative to the conventional common midpoint (CMP) stacking procedure. The data-driven, less user-interactive CRS method could be more cost efficient for shallow surveys, where the high sensitivity to velocity analysis makes data processing a critical step. We compared the results for two field data sets collected to image shallow and ultrashallow reflectors: an example of shallow Pwave reflection for targets in the first few hundred meters, and an example of SH-wave reflection for targets in the first 10 m. By processing the shallow P-wave records using the CMP method, we imaged several nearly horizontal reflectors with onsets from 60 to about 250 ms. The CRS stack produced a stacked section more suited for a subsurface interpretation, without any preliminary formal and time-consuming velocity analysis, because the imaged reflectors possessed greater coherency and lateral continuity. With CMP processing of the SHwave records, we imaged a dipping bedrock interface below four horizontal reflectors in unconsolidated, very low velocity sediments. The vertical and lateral resolution was very high, despite the very shallow depth: the image showed the pinchout of two layers at less than 10 m depth. The numerous traces used by the CRS stack improved the continuity of the shallowest reflector, but the deepest overburden reflectors appear unresolved, with not well-imaged pinchouts. Using the kinematic wavefield attributes determined for each stacking operation, we retrieved velocity fields fitting the stacking velocities we had estimated in the CMP processing. The use of CRS stack could be a significant step ahead to increase the acceptance of the seismic reflection method as a routine investigation method in shallow and ultrashallow seismics

Multicriticality of the (2+1)-dimensional gonihedric model: A realization of the (d,m)=(3,2) Lifshitz point

Multicriticality of the gonihedric model in 2+1 dimensions is investigated numerically. The gonihedric model is a fully frustrated Ising magnet with the finely tuned plaquette-type (four-body and plaquette-diagonal) interactions, which cancel out the domain-wall surface tension. Because the quantum-mechanical fluctuation along the imaginary-time direction is simply ferromagnetic, the criticality of the (2+1)-dimensional gonihedric model should be an anisotropic one; that is, the respective critical indices of real-space (\perp) and imaginary-time (\parallel) sectors do not coincide. Extending the parameter space to control the domain-wall surface tension, we analyze the criticality in terms of the crossover (multicritical) scaling theory. By means of the numerical diagonalization for the clusters with N\le 28 spins, we obtained the correlation-length critical indices (\nu_\perp,\nu_\parallel)=(0.45(10),1.04(27)), and the crossover exponent \phi=0.7(2). Our results are comparable to (\nu_{\perp},\nu_{\parallel})=(0.482,1.230), and \phi=0.688 obtained by Diehl and Shpot for the (d,m)=(3,2) Lifshitz point with the \epsilon-expansion method up to O(\epsilon^2)

Hybrid systems: a real-time interface to control engineering

This paper gives an introduction to a general hybrid systems model for definition of system requirements and a corresponding software architecture together with an example of their specialization for use in implementing a modeswitching controller for a hydraulic cylinder. 1. Introduction An important application area for real-time computing is embedded systems where the computing system provides intelligent control of a mechanical, chemical etc. plant or device. The software requirements for such applications depend heavily on the properties of the plant. These properties are usually investigated by control engineers that base their work on the theory of dynamic systems [3, 9]. The mathematical tool for this work is thus mathematical analysis, in particular the theory of differential equations. If the models are linear differential equations, there are standard techniques for implementing a corresponding discrete, sampled system in the form of a computer program, and the work for the s..

Intraphagolysosomal pH in canine and rat alveolar macrophages: flow cytometric measurements.

Intracellular dissolution of inhaled inorganic particles is an important clearance mechanism of the lung and occurs in phagolysosomal vacuoles of phagocytes. Flow cytometric measurements of intraphagolysosomal pH in alveolar macrophages (AM) obtained from beagle dogs, Wistar rats, and from a baboon were made using fluorescein isothiocyanate-labeled amorphous silica particles (FSP). AM were obtained by bronchoalveolar lavage. FSP were phagocytized by AM in cell suspensions incubated in full media for 24 hr up to 6 days. Dual laser flow cytometry was performed and six-parameter list mode data were recorded from forward scatter, side scatter, and fluorescence intensities at 530 nm excited at 457 nm and 488 nm as well as logarithmic fluorescence intensity at wavelengths 630 nm excited at 488 nm. In this way it was possible to discriminate viable AM with phagocytized FSP from lysing AM with phagocytized FSP and from cells without FSP and from free FSP. Viable cells were distinguished from lysing cells by staining with propidium iodide immediately before the flow cytometric measurement. A calibration curve for the pH value was determined from FSP suspended in buffered media at pH values ranging from 3.5 to 7.5. First flow cytometrical results indicated that after an incubation time of 24 hr, the mean intraphagolysosomal pH of viable AM was 4.7 +/- 0.3 for dogs and 5.1 +/- 0.5 for rats. The intraphagolysosomal pH of the baboon AM was 4.5

Oral health-related quality of life and loneliness among older adults

Loneliness is a serious concern in aging populations. The key risk factors include poor health, depression, poor material circumstances, and low social participation and social support. Oral disease and tooth loss have a significant negative impact on the quality of life and well-being of older adults. However, there is a lack of studies relating oral health to loneliness. This study investigated the association between oral health-related quality of life (through the use of the oral impact on daily performances—OIDP—measure) and loneliness amongst older adults living in England. Data from respondents aged 50 and older from the third (2006–2007) and fifth (2010–2011) waves of the English Longitudinal Study of Ageing were analyzed. In the cross-sectional logistic regression model that adjusted for socio-demographic, socio-economic, health, and psychosocial factors, the odds of loneliness were 1.48 (1.16–1.88; p < 0.01) higher amongst those who reported at least one oral impact compared to those with no oral impact. Similarly, in the fully adjusted longitudinal model, respondents who reported an incident oral impact were 1.56 times (1.09–2.25; p < 0.05) more likely to become lonely. The association between oral health-related quality of life and loneliness was attenuated after adjusting for depressive symptoms, low social participation, and social support. Oral health-related quality of life was identified as an independent risk factor for loneliness amongst older adults. Maintaining good oral health in older age may be a protective factor against loneliness

Spectral microscopic mechanisms and quantum phase transitions in a 1D correlated problem

In this paper we study the dominant microscopic processes that generate nearly the whole one-electron removal and addition spectral weight of the one-dimensional Hubbard model for all values of the on-site repulsion $U$. We find that for the doped Mott-Hubbard insulator there is a competition between the microscopic processes that generate the one-electron upper-Hubbard band spectral-weight distributions of the Mott-Hubbard insulating phase and finite-doping-concentration metallic phase, respectively. The spectral-weight distributions generated by the non-perturbative processes studied here are shown elsewhere to agree quantitatively for the whole momentum and energy bandwidth with the peak dispersions observed by angle-resolved photoelectron spectroscopy in quasi-one-dimensional compounds.Comment: 18 pages, 2 figure

Failure of Mean Field Theory at Large N

We study strongly coupled lattice QCD with $N$ colors of staggered fermions in 3+1 dimensions. While mean field theory describes the low temperature behavior of this theory at large $N$, it fails in the scaling region close to the finite temperature second order chiral phase transition. The universal critical region close to the phase transition belongs to the 3d XY universality class even when $N$ becomes large. This is in contrast to Gross-Neveu models where the critical region shrinks as $N$ (the number of flavors) increases and mean field theory is expected to describe the phase transition exactly in the limit of infinite $N$. Our work demonstrates that close to second order phase transitions infrared fluctuations can sometimes be important even when $N$ is strictly infinite.Comment: 4 pages, 3 figure

Does water fluoridation influence ethnic inequalities in caries in Brazilian children and adolescents?

Objectives: This study aimed to investigate the influence of community water fluoridation on ethnic inequalities in untreated dental caries among children and adolescents in Brazil while taking the human development context into account. / Methods: Data from a nationwide Brazilian epidemiological population oral health survey were used (SB Brazil 2010). Outcomes were caries prevalence measured by the proportion of individuals with one or more untreated decayed teeth and caries severity defined by the mean number of untreated decayed teeth (DT). Three different contexts were considered: 1—cities with no water fluoridation; 2—cities with water fluoridation and low Human Development Index (HDI); and 3—cities with water fluoridation and high HDI. The exposure was ethnic/racial group (White, Pardo, Black) and covariates were age, sex and household income. Multilevel logistic and negative binomial regressions were performed with 6696 children (aged 5 years) and 11 585 adolescents (aged 12 and 15-19 years). / Results: For both children and adolescents, ethnic differences in caries prevalence and mean DT were found in the nonfluoridated cities with low HDI and also in cities with high HDI, most of which were fluoridated. For example in nonfluoridated cities with low HDI, 5-year-old Pardo children were more likely to have untreated decay (OR = 1.22; 95% CI: 1.02, 1.46) and had more decayed teeth (RR = 1.18; 95% CI: 1.04, 1.34) than their White counterparts after adjusting for sex and household income. No statistically significant differences were observed in fluoridated cities with low HDI. / Conclusion: Water fluoridation appears to be associated with reduced ethnic inequalities in dental caries prevalence and mean DT among children and adolescents in more disadvantaged settings

Fermionization and Hubbard Models

We introduce a transformation which allows the fermionization of operators of any one-dimensional spin-chain. This fermionization procedure is independent of any eventual integrable structure and is compatible with it. We illustrate this method on various integrable and non-integrable chains, and deduce some general results. In particular, we fermionize XXC spin-chains and study their symmetries. Fermionic realizations of certain Lie algebras and superalgebras appear naturally as symmetries of some models. We also fermionize recently obtained Hubbard models, and obtain for the first time multispecies analogues of the Hubbard model, in their fermionic form. We comment on the conflict between symmetry enhancement and integrability of these models. Finally, the fermionic versions of the non integrable spin-1 and spin-3/2 Heisenberg chains are obtained.Comment: 24 pages, Latex. Minor typos corrected, one equation adde