Surveys report that 25–57 % of cats are overweight or obese. The most evinced cause is neutering. Weight loss often fails; thus, new strategies are needed. Obesity has been associated with altered gut bacterial populations and increases in microbial dietary energy extraction, body weight and adiposity. This study aimed to determine whether alterations in intestinal bacteria were associated with obesity, energy restriction and neutering by characterising faecal microbiota using 16S rRNA gene sequencing in eight lean intact, eight lean neutered and eight obese neutered cats before and after 6 weeks of energy restriction. Lean neutered cats had a bacterial profile similar to obese rodents and humans, with a greater abundance (P<0·05) of Firmicutes and lower abundance (P<0·05) of Bacteroidetes compared with the other groups. The greater abundance of Firmicutes in lean neutered cats was due to a bloom in Peptostreptococcaceae. Obese cats had an 18 % reduction in fat mass after energy restriction (P<0·05). Energy reduction was concurrent with significant shifts in two low-abundance bacterial genera and trends in four additional genera. The greatest change was a reduction in the Firmicutes genus, Sarcina, from 4·54 to 0·65 % abundance after energy restriction. The short duration of energy restriction may explain why few bacterial changes were observed in the obese cats. Additional work is needed to understand how neutering, obesity and weight loss are related to changes in feline microbiota and how these microbial shifts affect host physiology.

A large number of multispectral and stereo-image data are expected to become available as part of the Global Land Ice Measurements from Space project. We investigate digital elevation model extraction, anisotropic reflectance correction and selected glacier analysis tasks that must be developed to achieve full utility of these new data. Results indicate that glaciers in the Karakoram and Nanga Parbat Himalaya, northern Pakistan, exhibit unique spectral, spatial and geomorphometric patterns that can be exploited by various models and algorithms to produce accurate information regarding glacier extent, supraglacial features and glacier geomorphology The integration of spectral, spatial and geomorphometric features, coupled with approaches for advanced pattern recognition, can help geoscientists study glacier mass balance, glacier erosion, sediment-transfer efficiency and landscape evolution.

PyFAI is an open-source Python library for Fast Azimuthal Integration which provides 1D- and 2D-azimuthal regrouping with a clean programming interface and tools for calibration. The library is suitable for interactive use in Python. In optimising the speed of the algorithms there has been no compromise on the accuracy compared to reference software. Fast integrations are obtained by the combination of an algorithm ensuring that each pixel from the detector provides a direct contribution to the final diffraction pattern and an OpenCL implementation that can use graphics cards for acceleration. This contribution describes how the algorithms were modified to work better in parallel.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

This study investigated the direct and indirect roles of morphological awareness reading comprehension for Spanish-speaking language minority learners reading in English. Multivariate path analysis was used to investigate the unique contribution of derivational morphological awareness to reading comprehension as well as its indirect contributions via three hypothesized mediators for students in sixth, seventh, and eighth grade (N = 101). Results indicated a significant unique contribution of morphological awareness, controlling for phonemic decoding, listening comprehension, reading vocabulary, word reading fluency, and passage reading fluency. Results further indicated significant indirect contributions of morphological awareness via reading vocabulary and passage fluency, but not via word reading fluency. Findings suggest that morphological awareness may play multiple important roles in second-language reading comprehension.

Despite acknowledgement of the limited English vocabularies demonstrated by many language minority (LM) learners, few studies have identified skills that relate to variation in vocabulary growth in this population. This study investigated the concurrent development of morphological awareness (i.e., students’ understanding of complex words as combinations of meaningful smaller units) and vocabulary for LM learners in early adolescence. A cohort of Spanish-speaking LM learners (n = 90) was followed from fourth through seventh grade and assessed annually. Latent growth modeling results indicated a strong relationship between rates of growth in the two skills, such that learners with rapid growth in derivational morphological awareness also demonstrated rapid growth in vocabulary. Despite positive vocabulary growth during this period, the learners remained far below national norms. Findings highlight the need for language-focused instructional intervention for this population and suggest that morphological awareness may be a promising point of leverage for such instruction.

Using particle-in-cell simulations, we investigated the effect of group velocity dispersion (GVD) and third order dispersion (TOD) in the laser pulse on high-order harmonic generation and laser absorption in overdense plasmas. A 1020 W/cm−2, 35-fs transform-limited Gaussian pulse was stretched to 160 fs through chirping. When including GVD alone, the temporal pulse shape remains symmetric and no difference was seen in the harmonic spectra for opposite signs of GVD. However, when adding TOD to GVD, the pulse is no longer symmetric and noticeable differences in harmonics intensity were observed for opposite signs of TOD. We show that the higher harmonic intensity obtained with positive TOD is connected with a steeper front edge of the pulse and the appearance of strong modulations in the harmonic spectrum. The chirp broadens and shifts the harmonics. Laser energy absorption is also mostly affected by the pulse shape. Simple estimates indicate that, in the main example considered in this paper, about half the laser energy absorption (10%) is due to vacuum heating.

1-D computer simulations have been performed to study the influence of X-rays preheating on the compression of spherical laser-produced plasmas. The targets are glass microballoons filled with Neon at the initial pressure 10 bars. It is assumed that the only significant absorption process in the Neon is by inverse bremsstrahlung absorption. The results indicate that the radiative preheating energy has a nonnegligible effect on the compression, and a study of the Lawson criterion shows that this effect is more important for high-Z target shell materials and for thicker shells.

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

We perform systematic investigation of a new method for generating high-order harmonics, using ablation as the nonlinear medium. We place emphasis on clarifying the pump laser conditions for optimum harmonic yield. For this purpose, we use the Ti:Sapphire laser beams of the advanced laser light source (800 nm wavelength, 360 mJ total energy). We have independently varied the intensity of the prepulse (which creates the plasma ablation) and the intensity of the main pulse (which generates the harmonics), and studied their influence on the harmonic intensity. We show here that the presence of doubly ionized atoms in the ablation, created either by a strong prepulse intensity or by irradiating the main pulse, will suppress harmonic generation.

We describe here the present status of the Advanced Laser Light Source (ALLS) facility, a state-of-the-art multi-beam Ti:sapphire laser system presently under construction in Canada. ALLS is a national user facility to be commissioned in 2005 at the INRS campus near Montreal. The 25 fs ALLS multi-beam laser system has three components, each with different repetition rate and output energy. These multiple laser beams will be used to generate a “rainbow” of femtosecond pulses from the far infrared to hard X-rays, which can be combined to perform unique experiments, such as dynamic molecular imaging. In this paper, we describe two examples of experiments that are planned by our group with the ALLS facility. The first is the highly efficient generation of high-order harmonics using ablation medium. We demonstrate the generation of up to the 53rd harmonics (λ = 15 nm) of a Ti:sapphire laser pulse (150 fs, 10 mJ), using pre-pulse (210 ps, 24 mJ) produced boron ablation as the nonlinear medium. The second example is the demonstration of in-line phase-contrast imaging with an ultrafast (300 fs) laser-based hard X-ray source (Mo K-α line). Images of biological samples have shown great enhancement of contrast due to this technique, distinguishing details that are barely observable or even undetectable in absorption images.

The transport of hot electrons in solid density plasma created by a high-intensity subpicosecond laser pulse and the resulting heating and ionization of the bulk of plasma are simulated with the electron kinetic code “FPI.” Both the hot and the thermal electrons are treated kinetically. An analysis of the results in terms of a two Maxwellians fit to the numerically obtained distribution function is made.

The Galileo Near Infrared Mapping Spectrometer (NIMS) is currently obtaining spectral maps of Jupiter’s moons to determine the composition and spatial distribution of minerals on the satellite surfaces. Sulfur dioxide, as a frost or ice, covers much of Io’s surface, except in hot volcanic areas. A weak spectral feature at 3.15 μm suggests the presence of an OH containing surface compound (hydroxide, hydrate, or water) and a broad absorption above 1 μm is reasonably attributed to iron-containing minerals, such as feldspars and pyrite. Water is the dominant molecule covering Europa’s surface, occurring as ice but also as a hydrate. The trailing side shows high concentrations of these hydrous minerals, whose identifications are not yet established. Ganymede’s surface exhibits water absorption bands, largely due to ice but hydrates are also present. A dark component is present, but with a smaller proportion compared to Callisto. Some of the non-ice features seen on Ganymede are similar to those found in Callisto’s spectra (see below). Among the icy Galilean satellites, Callisto shows the least amount of water ice, covering about 10% of the surface in patchy concentrations. Most of the surface is covered with unidentified (as yet) dark minerals. The exposed ice is often associated with impact craters, implying that the darker material exists as a blanket over more pure ice. Non-ice spectral features at 3.88, 4.03, 4.25, and 4.57 μm are present in Callisto’s spectra (and some of these appear in Ganymede’s spectra), each with different spatial distributions. Laboratory spectra suggest that the 4.25-μm feature is due to carbon dioxide which is trapped in the surface grains. The band at 4.03 μm may be due to sulfur dioxide, which probably originated from Io. Molecules containing CN, SH, SiH, and perhaps deuterated constituents are candidates for the other features, some of which could be derived from shock-heated and modified material from impacts, perhaps of carbonaceous composition. There is evidence for the presence of hydrated minerals on Callisto, based on water band shifts and shapes.

Brillouin light has been used to measure the complex mechanical modulus of the molecular scale structure in oxide melts. The storage modulus reflects the degree of networking and structural integrity, while the loss modulus, which can be attributed to aperiodic motions of structural components, provides a measure of the mobility of these entities. rom the loss modulus it is possible to derive the zero-shear rate viscosity, which is characteristic of a structure in thermodynamic equilibrium, and thereby provide a less encumbered insight into the molecular scale mechanisms that are underlying to the viscous momentum transport.

In this paper we compare the visco-elastic behavior of alkali borates and alkali tellurites, particularly in the temperature range between Tg and the equilibrium melting point. While in borates several mechanisms can be identified as contributing to structural relaxation, in tellurites a single mechanism dominates. The assumption of thermo-rheological simplicity, however, is invalid, and a new visco-elastic model has been developed for the description of our results.

The Brillouin light scattering technique was used to study short timerelaxations in glass forming oxide melts. The line shape analysis ofBrillouin spectra yields a complex mechanical Modulus. The temperaturedependence of this modulus provides insight into the structuraldisintegration above the glass transition, as well as the thermallyactivated mechanisms which facilitate the momentum transport in the processof viscous dissipation.

A series of binary and ternary alkali borates and alkali silicates have beeninvestigated. The results show fundamental differences in the way alkalications affect the network structure in borates as compared to silicates.While these cations move relatively freely within the rigid silicatenetwork, their motions are strongly coupled to the network relaxation inborates. The activation energies for cation motion are in good agreementwith those found by other methods.

Amorphous silicon carbide films (a–SixC1−x :H) deposited by the argon- or helium-diluted PECVD technique were studied as a function of their composition. Microstructural investigations were mainly achieved by means of FTIR and XPS techniques. Nuclear techniques were used to obtain precise information on the film hydrogen content. The Si–H IR-absorption band was deconvoluted in different monohydride and dihydride silicon environments. The existence of SiH2 bonds in the Si-rich composition was evidenced. From the analysis of the C–H and Si–H absorption bands it is shown that hydrogen atoms are preferentially bonded to carbon atoms. The deconvolution of the Si2p core level peak suggests that above a composition of x ∊ 0.5, the noncarburized (Si, Si, H) local environment contribution increases to the detriment of the hydrocarburized (Si, C, H) environments. From the evolution of the C1s peak, it can be deduced that there is a change in the carbon atom bonding states when the film composition is varied. These results are correlated and discussed in terms of the local bonding environments and their evolution with film composition.

The Brillouin light scattering technique is used for the investigation of structural relaxations in glass-forming liquids at high temperatures. From the analysis of the line shapes of Rayleigh and Brillouin peaks, the friction coefficients, which are associated with the atomic scale mechanisms of the structural relaxations in these systems, are determined. Results for a series of K2O-SiO2 compositions, which were chosen as model substances, are reported. As a function of temperature, maxima in the Brillouin line widths were observed, which reflect resonant conditions of molecular scale structural motions, where the relaxation time is of the order of the reciprocal Brillouin frequency shift. Due to thermal activation of the component mobilities, different relaxation mechanisms couple at different temperatures. Typically, at least one strongly absorbing regime is observed in between the glass transition and the equilibrium melting temperatures. The prominence of this regime decreases with increasing silica concentration. The friction coefficients approach the hydrodynamic viscosity in the high temperature limit, when the relaxation times become short in comparison with the time scale of the Brillouin shift.

Li+ ions are highly mobile in LiCl-Li2O·2B23 glasses to the extent that the decou-pling of conductive modes of motion from the viscous modes, assessed at the glass transition temperature Tg by a relaxation time ratio, is one of the greatest known. The interpretation of the structure of this glass system and its relation to conductivity decoupling is not very advanced at this time but there seems to be a distinction drawn between the chloroborate structure and the structure of the corresponding AgCl-Ag borate and AgI-borate glasses. The latter have frequently been discussed in terms of α-AgI percolating clusters although the available thermodynamic evidence indicates chemical ordering (negative deviations from ideal mixing) as opposed to any sort of clustering (positive deviations from ideal mixing). The LiCl-Li2O-B2O3 system is interesting to us because simple transferable effective pair potentials are available for all species in the system and ion dynamics computer simulations should be capable of giving useful insights into the structure, energetics, and dynamics of the system. We present diffusivity data as a function of temperature for several compositions in the LiClLi2O·2B2O3 system and observe that the Li+ mobility remains high below the simulated, glass transition. Surprisingly, the Cl− anion mobility also remains high, raising a question about anion transport numbers in these glasses. Computed conductivities agree with laboratory data in the liquid state but exceed laboratory data in the glassy state in the direction expected from the high fictive temperature of simulated glass. Deviations from additivity in mixing energy in this system show a weak tendency to clustering of LiCl in the structure which suggests a need for laboratory mixing enthalpy studies.