Absolute pore size distributions from NMR

NMR measurements on core samples saturated with brine returns valuable information on the porous structure of the rock core. Monitoring a single fluid component in a relaxation experiment reflects the pore size distribution and thus the degree of sorting of the porous rock. The basic assumptions are that the mobility of the component confined in the porous rock is of such a value that a small fraction of the probing molecules experience the surfaces of the pores and that the surface relaxation strength is fairly independent of pore size. Then one may combine diffusion measurements at short observation times returning a value for the average surface to volume ratio with ordinary relaxation time measurements to obtain an absolute pore size distribution instead of the standard T2 distributions or T1-T2 correlated two dimensional distributions

Women with early maltreatment experience show increased resting-state functional connectivity in the theory of mind (ToM) network.

Background: Experience of childhood maltreatment significantly increases the risk for the development of psychopathology and is associated with impairments in socio-cognitive skills including theory-of-mind (ToM). In turn, neural alterations in ToM processing might then influence future interpersonal interaction and social-emotional understanding. Objective: To assess resting-state activity in the theory-of-mind network in traumatized and non-traumatized persons. Methods: Thirty-five women with a history of childhood maltreatment and 31 unaffected women completed a resting-state scan and a ToM localizer task. The peak coordinates from the localizer were used as the seed regions for the resting-state functional connectivity (RSFC) analyses (temporo-parietal junction, dorsomedial prefrontal cortex, middle temporal gyrus and precuneus). Results: Child abuse was associated with increased RSFC between various ToM regions including the precuneus and the brainstem suggesting altered hierarchical processing in ToM regions. Number of types of abuse was driving the effect for the temporo-parietal junction and the brainstem, while the severity of abuse was linked to increased RSFC between the middle temporal gyrus and the frontal cortex. Post-hoc analyses of brainstem regions indicated the involvement of the serotonergic system (dorsal raphe). Conclusions: The data indicate a lasting impact of childhood maltreatment on the neural networks involved in social information processing that are integral to understanding others' emotional states. Indeed, such altered neural networks may account for some of the interpersonal difficulties victims of childhood maltreatment experience

Model Checking Classes of Metric LTL Properties of Object-Oriented Real-Time Maude Specifications

This paper presents a transformational approach for model checking two important classes of metric temporal logic (MTL) properties, namely, bounded response and minimum separation, for nonhierarchical object-oriented Real-Time Maude specifications. We prove the correctness of our model checking algorithms, which terminate under reasonable non-Zeno-ness assumptions when the reachable state space is finite. These new model checking features have been integrated into Real-Time Maude, and are used to analyze a network of medical devices and a 4-way traffic intersection system.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

Measurement of Lagrangian velocity in fully developed turbulence

We have developed a new experimental technique to measure the Lagrangian velocity of tracer particles in a turbulent flow, based on ultrasonic Doppler tracking. This method yields a direct access to the velocity of a single particule at a turbulent Reynolds number $R_{\lambda} = 740$. Its dynamics is analyzed with two decades of time resolution, below the Lagrangian correlation time. We observe that the Lagrangian velocity spectrum has a Lorentzian form $E^{L}(\omega) = u_{rms}^{2} T_{L} / (1 + (T_{L}\omega)^{2})$, in agreement with a Kolmogorov-like scaling in the inertial range. The probability density function (PDF) of the velocity time increments displays a change of shape from quasi-Gaussian a integral time scale to stretched exponential tails at the smallest time increments. This intermittency, when measured from relative scaling exponents of structure functions, is more pronounced than in the Eulerian framework.Comment: 4 pages, 5 figures. to appear in PR

Modulation of equatorial turbulence by a tropical instability wave

Strong modulation of turbulent mixing by a westward-propagating tropical instability wave (TIW) was observed in the stratified shear layer between the equatorial undercurrent (EUC) and the surface mixed layer during October and November 2008 at 0°N 140°W. The unique deep diurnal-cycle mixing in the stratified layer beneath the equatorial cold tongue was observed where nighttime turbulent mixing was a factor of 10 greater than during daytime. The turbulent kinetic energy dissipation rate, ε, was Ο(10⁻⁶) W kg⁻¹, and the turbulent heat flux was ∼−500 W m⁻², at least 5–10 times greater than observed previously in the central equatorial Pacific. Turbulence mixing varied significantly during the four distinct phases of the meridional flow associated with the TIW. Observations during the northward-to-southward transition recorded the largest values of reduced shear squared, the thickest nighttime surface mixed layer, the deepest penetration of the deep-cycle turbulence, and the largest turbulent heat flux and largest integrated ε in the deep-cycle layer (DCL). During steady southward flow, the depth of the bases of the nighttime surface mixed layer and of the DCL were the shallowest. A 50-m-thick layer of strong turbulence was observed immediately above the EUC core during the northward-to-southward and steady southward phases. Here, the average ε exceeded 10⁻⁶ W kg⁻¹, the eddy diffusivity exceeded 10⁻³ m² s⁻¹, and the turbulent heat flux was ∼−500 W m⁻². To parameterize mixing in the central equatorial Pacific accurately, numerical models must simulate the enhancement of mixing associated with TIWs and also the variability of mixing in different TIW phases

Formal Model Engineering for Embedded Systems Using Real-Time Maude

This paper motivates why Real-Time Maude should be well suited to provide a formal semantics and formal analysis capabilities to modeling languages for embedded systems. One can then use the code generation facilities of the tools for the modeling languages to automatically synthesize Real-Time Maude verification models from design models, enabling a formal model engineering process that combines the convenience of modeling using an informal but intuitive modeling language with formal verification. We give a brief overview six fairly different modeling formalisms for which Real-Time Maude has provided the formal semantics and (possibly) formal analysis. These models include behavioral subsets of the avionics modeling standard AADL, Ptolemy II discrete-event models, two EMF-based timed model transformation systems, and a modeling language for handset software.Comment: In Proceedings AMMSE 2011, arXiv:1106.596