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Elemental, chemical, and structural analysis of polycrystalline materials at the micron scale is frequently carried out using microfocused synchrotron X-ray beams, sometimes on multiple instruments. The Maia pixelated energy-dispersive X-ray area detector enables the simultaneous collection of X-ray fluorescence (XRF) and diffraction because of the relatively large solid angle and number of pixels when compared with other systems. The large solid angle also permits extraction of surface topography because of changes in self-absorption. This work demonstrates the capability of the Maia detector for simultaneous measurement of XRF and diffraction for mapping the short- and long-range order across the grain structure in a Ni polycrystalline foil.
The influence of baseline severity has been examined for antidepressant
medications but has not been studied properly for cognitive–behavioural
therapy (CBT) in comparison with pill placebo.
To synthesise evidence regarding the influence of initial severity on
efficacy of CBT from all randomised controlled trials (RCTs) in which
CBT, in face-to-face individual or group format, was compared with
pill-placebo control in adults with major depression.
A systematic review and an individual-participant data meta-analysis
using mixed models that included trial effects as random effects. We used
multiple imputation to handle missing data.
We identified five RCTs, and we were given access to individual-level
data (n = 509) for all five. The analyses revealed that
the difference in changes in Hamilton Rating Scale for Depression between
CBT and pill placebo was not influenced by baseline severity (interaction
P = 0.43). Removing the non-significant interaction
term from the model, the difference between CBT and pill placebo was a
standardised mean difference of –0.22 (95% CI –0.42 to –0.02,
P = 0.03, I2 = 0%).
Patients suffering from major depression can expect as much benefit from
CBT across the wide range of baseline severity. This finding can help
inform individualised treatment decisions by patients and their
A new generation of solar instruments provides improved spectral, spatial, and temporal resolution, thus facilitating a better understanding of dynamic processes on the Sun. High-resolution observations often reveal multiple-component spectral line profiles, e.g., in the near-infrared He i 10830 Å triplet, which provides information about the chromospheric velocity and magnetic fine structure. We observed an emerging flux region, including two small pores and an arch filament system, on 2015 April 17 with the ‘very fast spectroscopic mode’ of the GREGOR Infrared Spectrograph (GRIS) situated at the 1.5-meter GREGOR solar telescope at Observatorio del Teide, Tenerife, Spain. We discuss this method of obtaining fast (one per minute) spectral scans of the solar surface and its potential to follow dynamic processes on the Sun. We demonstrate the performance of the ‘very fast spectroscopic mode’ by tracking chromospheric high-velocity features in the arch filament system.
We present deep 1.6 and 2.2 μm images of the central parsec of the Galaxy at a resolution of 0.15″. Most of the flux in earlier seeing limited images comes from about 340 unresolved stellar sources with K≤14. The IRS 16 and 13 complexes are resolved into about two dozen and half a dozen sources, a number of which are probably luminous hot stars. We confirm the presence of a blue near infrared object (K≈13) at the position of the compact radio source Sgr A∗. The spatial centroid of the source number distribution is consistent with the position of Sgr A∗ but not with a position in the IRS 16 complex. The stellar surface density in the central 10″ is very well fitted by an isothermal cluster model with a well defined core radius. The derived core radius of all 340 sources is 0.15±0.05 pc. The central stellar density is a few times 107 M⊙ pc−3. Buildup of massive stars by merging of lower mass stars and collisional disruption of giant atmospheres are very probable processes in the central 0.2 pc.
This paper is based in part on evidence and insights found in various studies. These studies had as their objects to prove (or at least to demonstrate the plausibility of) either an analysis of a language or a theory of grammar. Their evidence, in addition to that which is new here, demonstrates the difficulty of using superficial relational information for semantic interpretation. It may be noted that, some years ago, Jespersen pointed out many such difficulties, though not with the orientation of relating syntax to semantics.
We present the first speckle interferometric observations of R CrB, the prototype of a class of peculiar stars which undergo irregular declines in their visible light curves. The observations were carried out with the 6 m telescope at the Special Astrophysical Observatory near maximum light (V = 7, 1996 Oct. 1) and at minimum light (V = 10.61, 1999 Sep. 28). A spatial resolution of 75 mas was achieved in the K-band. The dust shell around R CrB is partially resolved, and the visibility is approximately 0.8 at a spatial frequency of 10 cycles/arcsec. The two-dimensional power spectra obtained at both epochs do not show any significant deviation from circular symmetry. The visibility function and spectral energy distribution obtained near maximum light can be simultaneously fitted with a model consisting of the central star and an optically thin dust shell with density proportional to r−2 and amorphous carbon as its constituent. The inner boundary of the shell is found to be 82 R* (19 mas) with a temperature of 920 K near maximum light. However, this simple model fails to simultaneously reproduce the visibility and spectral energy distribution obtained at minimum light. We show that this discrepancy can be attributed to thermal emission from a newly formed optically thick dust cloud. Simultaneous fits of the observed SED and visibility with models including a thermally emitting dust cloud suggest the presence of a newly formed dust cloud as hot as 1200 K with a radius of 4 – 5R*, in addition to an optically thin dust shell whose inner boundary is ~ 170 R* with a temperature of ~ 690 K. Alternatively the discrepancy can be attributed to an unusual extinction curve of dust grains in the obscuring cloud which was present in front of the star at minimum light. The details of the observations and modeling are described in Ohnaka et al. (2001, A&A 380, 212).
The center of the stellar association in 30 Doradus, R136 (HD 38268), is an unusually high concentration of massive and bright O, B and Wolf-Rayet stars and represents the closest example of an intense starburst region.
We present high-resolution J–, H–, and K–band observations of the carbon star IRC+10 216. The images were reconstructed from 6 m telescope speckle interferograms using the speckle masking bispectrum method. The H image has the unprecedented resolution of 70 mas. The H and K images consist of at least five dominant components within a 0.21 arcsec radius and a fainter asymmetric nebula. The J-, H-, and K—band images seem to have an X-shaped bipolar structure. A comparison of our images from 1995, 1996, 1997, and 1998 shows that the separation of the two brightest components A and B increased from ∼ 193 mas in 1995 to ∼ 246 mas in 1998.
The cometary shapes of component A in the H and J images and the 0.79 μm and 1.06 μm HST images suggest that the core of A is not the central star, but the southern (nearer) lobe of the bipolar structure. The position of the central star is probably at or near the position of component B, where the H—K color has its largest value of H—K = 4.2.
If the star is located at or near B, then the components A, C, and D are located close to the inner boundary of the dust shell at separations of ∼200 mas ∼30 AU (projected distance) ∼6 stellar radii for a distance of ∼ 150 pc, in agreement with our 2-dimensional radiative transfer modelling.
In addition to IRC+ 10 216 we studied the stellar disks and the dust shells of several related objects. Angular resolutions of 24 mas at 700 nm or 57 mas 1.6 μm were achieved.
Cattle are members of the Ruminantia, which represent the most successful group of extant large herbivores in terms of species diversity. Ruminants have a multi-chambered forestomach, similar to other foregut fermenters like kangaroo, hippos, peccaries or sloths (Langer 1988); this means that plant material is partly digested by symbiotic microbes before the whole digesta – which includes the partly digested diet and the microbes – is passed on to the lower digestive tract where the herbivore’s own enzymes further digest this mixture. Because microbial protein is a major component of this mixture, foregut fermenters produce a set of specific enzymes in their glandular stomach and small intestine that help break down microbial cells, so that their protein can be used (Pacheco et al. 2007). Functional ruminants – the phylogenetic ruminants as well as the camelids – combine simple foregut fermentation with peculiar sorting mechanisms that assure that larger digesta particles are regurgitated and re-masticated (ruminated). This process of rumination is an obligatory physiological feature, facilitates a more efficient particle size reduction (Fritz et al. 2009), higher digestive efficiencies (Foose 1982) and potentially also higher food intake levels than observed in non-ruminant foregut fermenters (Clauss et al. 2010a).
Ruminant digestive anatomy and physiology
The ruminant stomach consists of four compartments – three representing the forestomach complex, and the last representing the glandular stomach (‘abomasum’), the equivalent of the stomach of monogastric animals (Hofmann & Schnorr 1982). The three forestomach compartments are, in the sequence of the digestive process, the rumen, the reticulum and the omasum (Figure 6.1). From the outside, the rumen and the reticulum form a unit – a large fermentation chamber with several sub-compartments, including the dorsal and the ventral rumen, the dorsal and ventral rumen blindsacs, the atrium ruminis and the reticulum. The whole complex is often referred to as the reticulorumen (RR). The reticulum is the most cranial part of the RR. On the right side of the RR, the omasum is a distinct structure. In contrast to the RR, which has a consistency of the digesta it contains, the omasum is more solid to the touch, and ball- or bean-shaped. The omasum leads to the abomasum, which in turn leads to the small and then the large intestine.
We present four wave mixing experiments on GaN. We find an intrinsic homogeneous broadening of the A-exciton of 1.67 meV. A pronounced beating with a period of 0.52 ps is observed at excitation energies between the A- and the B-exciton and corresponds to an energy splitting of 7.98 meV of A- and B-exciton.
A modified critical point model dielectric function for graphene is derived here and used to analyze spectroscopic ellipsometry data obtained over a wide spectral range from 3 to 9 eV. Critical point and exciton resonance energies are extracted and discussed. Our findings indicate that epitaxial graphene on SiC to exhibits equivalent exciton behavior to that of suspended graphene. We further apply our model dielectric function to evaluate dielectric function data for highly oriented pyrolytic graphite reported in the literature. Excellent agreement is found between the critical point model developed here and the literature data even for the low energy spectral range up to 1 eV.
The early Neolithic in northern Central Europe ought to be the theatre in which incoming farmers meet local hunter-gatherers, with greater or lesser impact. By way of contrast, the authors use isotope analysis in a cemetery beside the Danube to describe a peaceful, well-integrated community with a common diet and largely indigenous inhabitants. Men and women may have had different mobility strategies, but the isotopes did not signal special origins or diverse food-producing roles. Other explanations attend the variations in the burial rites of individuals and their distribution into cemetery plots.
Although predictions suggest that ocean acidification will significantly impact polar oceans within 20–30 years, there is limited information regarding present-day pH dynamics of the Southern Ocean. Here, we present novel high-frequency observations of pH collected during spring of 2010 using SeaFET pH sensors at three locations under fast sea ice in the southern Ross Sea. During these deployments in McMurdo Sound, baseline pH ranged between 8.019–8.045, with low to moderate overall variation (0.043–0.114 units) on the scale of hours to days. The variation was predominantly in the direction of increased pH relative to baseline observations. Estimates of aragonite saturation state (ΩAr) were > 1 with no observations of subsaturation. Time series records such as these are significant to the Antarctic science community; this information can be leveraged towards framing more environmentally relevant laboratory experiments aimed at assessing the vulnerability of Antarctic species to ocean acidification. In addition, increased spatial and temporal coverage of pH datasets may reveal ecologically significant patterns. Specifically, whether such variation in natural ocean pH dynamics may drive local adaptation to pH variation or provide refugia for populations of marine calcifiers in a future, acidifying ocean.
Electrochemical deposition of metals and alloys onto metallic substrates plays an important role in many modern technologies. Usually, a photolithographic patterning process is used to produce the desired feature on the substrate surface. An alternative method to patterned metal deposition on semiconductors is presented here: it is based on changing the electrochemical properties of the semiconductor by controlled surface defect creation. A focused ion beam (FIB) was used to introduce defects into p-Si, followed by a selective electrochemical reaction to produce metal structures in the sub-micrometer range.
In this work we study the selective deposition behavior of Cu on FIB sensitized surface locations and show that crystallite growth follows a three- dimensional growth law. Crystallites grow very rapidly in a first phase and reach a size of roughly 200nm after 5s. Factors determining nucleation, growth, and coalescence of metal clusters are identified and investigated.
The properties of small clusters Fe3 and Fe5, in which the non-collinearity of magnetic density is expected to be important, and of larger nanoparticles (consisting of up to 62 atoms) are studied from first principles making use of density functional theory, norm-conserving pseudopotential and numerical local orbitals method, as implemented in the SIESTA code. We concentrate on the interplay of lattice relaxation, mostly pronounced near the surface of particles, and the particles' magnetic characteristics. Previously obtained theoretical findings of enhanced magnetic moments in outer shells of nanoparticles are confirmed. These results are refined by taking structure relaxation into account and by considering more representative bcc- and fcc-related particles; moreover, we allowed antiferromagnetic ordering along with ferromagnetic one.
Silver nanoparticles were prepared by the method of mixing of two microemulsions having similar chemical composition but different reactants in their respective aqueous core. One microemulsion contains silver nitrate in the aqueous core and other contains sodium borohydride. The silver nanoparticles formed were characterized using UV-Visible absorption spectra and TEM micrographs. Effect of chain length of solvent and addition of Arlacel-20 to the AOT/Heptane, AOT/Decane and AOT/Dodecane microemulsion on particle size and absorption spectra of silver nanoparticles was studied. TEM photographs showed agglomerated and bigger particles in case of pure AOT/dodecane whereas addition of Arlacel-20 showed dispersed and smaller particles. Reaction kinetics was observed for silver nanoparticles using UV-visible spectrophotometer. Silver nanoparticles prepared using pure AOT surfactant showed plasmon band (416 nm) immediately after preparation whereas no absorption band of silver nanoparticles was observed for mixed surfactant microemulsion of AOT and Arlacel 20 for few hours indicating the reaction kinetics is slowed down upon addition of Arlacel-20. Growth rate of silver nanoparticles was plotted by monitoring absorption coefficient ratio (ε416/ε475) as a function of time. AOT/heptane system showed slower growth rate as compared to AOT/decane and AOT/dodecane and also larger particle size. Presence of Arlacel-20 significantly decreases the growth rate in all three alkanes and this observation can be explained using the concept of rigidity of surfactant film at the oil/water interface. It is proposed that higher the interfacial viscosity, slower is the coalescence rate of nanodroplets in the microemulsion system, and hence slower the growth rate of particles and smaller is the final particle size.
The experimental analysis of dry laser cleaning efficiency is done for certified spherical particle (SiO2, 5.0, 2.5, 1.0 and 0.5 μm) from different substrates (Si, Ge and NiP). The influence of different options (laser wavelength, incident angle, substrate properties, i.e. type of material, surface roughness, etc.) on the cleaning efficiency is presented in addition to commonly analyzed options (cleaning efficiency versus laser fluence and particle size). Found laser cleaning efficiency demonstrates a great sensitivity to some of these options (e.g. laser wavelength, angle of incidence, etc.). Partially these effects can be explained within the frame of the Mie theory of scattering. Other effects (e.g. influence of roughness) can be explained along the more complex line, related to examination of the problem “particle on the surface” beyond the Mie theory. 0.5 μm spherical silica particles were placed on Silicon (100) substrate. After laser irradiation with a 248 nm KrF excimer laser, hillocks with size of about 100 nm were obtained at the original position of the particles. Mechanism of the formation of the sub-wavelength structures were investigated and found to be the near-field optical resonance effect induced by particles on surface. Theoretical prediction of the near-field light intensity distribution was presented, which was in agreement with the experimental result.