Intracerebral oxytocin is important for the onset of maternal behavior in inexperienced ewes delivered under peridural anesthesia.

Measurement of cerebrospinal concentrations of oxytocin (OT) in intact and peridural-anesthetized ewes showed that central release of OT during parturition is inhibited by this anesthesia. Also, observations of maternal behavior and attraction to amniotic fluid (AF) in inexperienced peridural-anesthetized parturient ewes after intracerebroventricular injections of either OT (2?×?10 μg) or saline showed that OT infusions increased the proportion of maternal females (2/17 vs 10/20; p?=?.01) and attraction to AF. This study confirms that in sheep vaginocervical stimulation activates the oxytocinergic system, which induces the onset of maternal behavior, and that this action is not limited to maternally experienced females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrical and optical properties of MoSe2 films prepared by r.f. magnetron sputtering

The electrical resistivity of MoSe₂ films prepared by r.f. magnetron sputtering was measured between 300 and 10 K. The main sputtering parameter governing the physical properties of the films was found to be the substrate temperature T_sub. The room temperature resistivity of the as-sputtered films increased from $\text{1.7 × 10}{}^{-1}\text{Ω}\text{cm}$(T_sub = -70 °C) to $\text{1.4 × 10}{}^1\text{Ω}\text{cm}\text{(T}{}_{\mathrm{<mtext>sub</mtext>}}\text{= 150 °}\text{C}\text{)}$. A check of the thermo-electrical response showed that the majority charge carriers are holes except for films deposited at T_sub = 150 °C which are n type. Hall effect measurements indicated very low Hall mobilities (3–5 cm² V^-1 s^-1). Thermal annealing increased the room temperature resistivities by more than one order of magnitude for the specimens sputtered at a low substrate temperature. The optical properties were weakly influenced by the process conditions. The optical gap was determined to be 1.06 eV.     

Fitting polynomial surfaces to triangular meshes with Voronoi squared distance minimization

This paper introduces Voronoi squared distance minimization (VSDM), an algorithm that fits a surface to an input mesh. VSDM minimizes an objective function that corresponds to a Voronoi-based approximation of the overall squared distance function between the surface and the input mesh (SDM). This objective function is a generalization of the one minimized by centroidal Voronoi tessellation, and can be minimized by a quasi-Newton solver. VSDM naturally adapts the orientation of the mesh elements to best approximate the input, without estimating any differential quantities. Therefore, it can be applied to triangle soups or surfaces with degenerate triangles, topological noise and sharp features. Applications of fitting quad meshes and polynomial surfaces to input triangular meshes are demonstrated.     

Post-buckling dynamic behavior of self-assembled 3D microstructures

The paper presents the snap-through phenomenon in the case of micro fabricated clamped-clamped buckled beam. This dynamic post-buckling behavior is likely to occur in 3D microstructures when they are subjected to large vibration amplitudes. The main difference between this work and previous studies is the MEMS specific beam dimension, especially the large initial deflection of the buckled beam that involves the inversion of the two first resonance frequencies. The mathematical development allows showing how the vibration amplitude of the supporting base affects the post-buckling dynamic behavior of the beam. For each frequency, the limit between the stable behavior and the snap-through behavior is evaluated. Moreover, the effect of environment is taken into account from the damping point of view. Samples are fabricated and the experiment is described. Measurements are compared to the theoretical approach and the results are in good agreement with the proposed model.     

Adjacent versus coincident representations of geospatial uncertainty: Which promote better decisions?

3D geological models commonly built to manage natural resources are much affected by uncertainty because most of the subsurface is inaccessible to direct observation. Appropriate ways to intuitively visualize uncertainties are therefore critical to draw appropriate decisions. However, empirical assessments of uncertainty visualization for decision making are currently limited to 2D map data, while most geological entities are either surfaces embedded in a 3D space or volumes.This paper first reviews a typical example of decision making under uncertainty, where uncertainty visualization methods can actually make a difference. This issue is illustrated on a real Middle East oil and gas reservoir, looking for the optimal location of a new appraisal well. In a second step, we propose a user study that goes beyond traditional 2D map data, using 2.5D pressure data for the purposes of well design. Our experiments study the quality of adjacent versus coincident representations of spatial uncertainty as compared to the presentation of data without uncertainty; the representations' quality is assessed in terms of decision accuracy. Our study was conducted within a group of 123 graduate students specialized in geology.     

Influence of Ge addition on the morphology and properties of TiN thin films deposited by magnetron sputtering

Thin films of TM-X-N (TM stands for early transition metal and X = Si, Al, etc.) are used as protective coatings. The most investigated among the ternary composite systems is Ti-Si-N. The system Ti-Ge-N has been chosen to extend the knowledge about the formation of nanocomposite films. Ti-Ge-N thin films were deposited by reactive magnetron sputtering on Si and WC-Co substrates at T_s = 240 °C, from confocal Ti and Ge targets in mixed Ar/N₂ atmosphere. The nitrogen partial pressure and the power on the Ti target were kept constant, while the power on the Ge target was varied in order to obtain various Ge concentrations in the films. No presence of Ge-N bonds was detected, while X-ray photoelectron spectroscopy measurements revealed the presence of Ti-Ge bonds. Transmission Electron Microscopy investigations have shown important changes induced by Ge addition in the morphology and structure of Ti-Ge-N films. Electron Energy-Loss Spectrometry study revealed a significant increase of Ge content at the grain boundaries. The segregation of Ge atoms to the TiN crystallite surface appears to be responsible for limitation of crystal growth and formation of a TiGe_y amorphous phase.     

Fabrication and in situ characterization of microcapsules in a microfluidic system

We have designed a microfluidic system that enables both the fabrication of calibrated capsules and the in situ characterization of their mechanical properties. The fabrication setup consists of a double flow-focusing system. A human serum albumin aqueous solution is introduced in the central channel of a first Y-junction. Intercepted by the lateral flows of a hydrophobic phase, it is dispersed into microdroplets. A cross-linking agent is then introduced at a second Y-junction allowing a membrane to form around the droplets. The time of cross-linking is controlled by the length of a wavy channel located downstream of the second junction. A cylindrical microchannel finally enables to deform and characterize the capsules thus formed. The mechanical properties of the capsule membrane are obtained by inverse analysis. The results show that the drop size increases with the flow rate ratio between the central and lateral channels. The mean shear modulus of the capsules fabricated after 23 s of cross-linking is of the order of the surface tension between the two phases indicating that a reaction time of 23 s is too short for an elastic membrane to form around the droplet. When the cross-linking time is increased to 60 s, the microcapsules surface is wrinkled, thus confirming that a solid membrane is formed around the drop. The mean shear modulus of the capsule membrane increases with the cross-linking time, which is in agreement with our previous chemical results and proves that a fine control of the mechanical properties is possible by choosing adequately the control parameters of the system.