2,119 research outputs found
Electron paramagnetic resonance of rutile pigments
An Electron Paramagnetic Resonance study of rutile (TiO(_2)) pigments doped with either iron or chromium has been performed. The spectra of the Cr(^3+) ion has been observed and confirmed by computation. In iron doped pigments a signal with g = 4.28 was observed and has been attributed to the Fe(^3+) ion in a site of rhombic symmetry. The effect of irradiation by light on the Fe(^3*) ion in a substitutional site has been examined and seen to be different from that for single crystal samples ; only wavelengths longer than 700 nm affect it. A light-generated line was observed with 'g' values g(_11) = 2.010, g(_1) = 2.005. The response of this line is related to the concentration of iron. The data has been analysed and correlates reasonably well with accepted models for the positions of the defect centres within the band gap
Longitudinally diode-pumped Nd:YAG double-clad planar waveguide laser
We report the demonstration of a near-diffraction-limited, compact, diode-end-pumped double-clad planar waveguide Nd:YAG laser. Efficient laser operation was achieved for the three dominant Nd3+ transitions at 1.064”m 0.946”m, and 1.32”m, with TE polarised output powers of 1.33W, 0.57W, and 0.33W for the available output couplers. The output beam from the monolithic plane-plane laser cavity had measured M2 values of 1.0 and 1.8, perpendicular and parallel to the plane of the waveguide respectively
Culturally learned first impressions occur rapidly and automatically and emerge early in development
Previous research indicates that first impressions from faces are the products of automatic and rapid processing and emerge early in development. These features have been taken as evidence that first impressions have a phylogenetic origin. We examine whether first impressions acquired through learning can also possess these features. First, we confirm that adults rate a person as more intelligent when they are wearing glasses (Study 1). Next, we show this inference persists when participants are instructed to ignore the glasses (Study 2) and when viewing time is restricted to 100 ms (Study 3). Finally, we show that 6âyearâold, but not 4âyearâold, children perceive individuals wearing glasses to be more intelligent, indicating that the effect is seen relatively early in development (Study 4). These data indicate that automaticity, rapid access and early emergence are not evidence that first impressions have an innate origin. Rather, these features are equally compatible with a learning model
Advancing national greenhouse gas inventories for agriculture in developing countries : improving activity data, emission factors and software technology
Peer reviewedPublisher PD
Evaluating observed versus predicted forest biomass: R-squared, index of agreement or maximal information coefficient?
The accurate prediction of forest above-ground biomass is nowadays key to implementing climate change mitigation policies, such as reducing emissions from deforestation and forest degradation. In this context, the coefficient of determination () is widely used as a means of evaluating the proportion of variance in the dependent variable explained by a model. However, the validity of for comparing observed versus predicted values has been challenged in the presence of bias, for instance in remote sensing predictions of forest biomass. We tested suitable alternatives, e.g. the index of agreement () and the maximal information coefficient (). Our results show that renders systematically higher values than , and may easily lead to regarding as reliable models which included an unrealistic amount of predictors. Results seemed better for , although favoured local clustering of predictions, whether or not they corresponded to the observations. Moreover, was more sensitive to the use of cross-validation than or , and more robust against overfitted models. Therefore, we discourage the use of statistical measures alternative to for evaluating model predictions versus observed values, at least in the context of assessing the reliability of modelled biomass predictions using remote sensing. For those who consider to be conceptually superior to , we suggest using its square , in order to be more analogous to and hence facilitate comparison across studies
Slow relaxation in the two dimensional electron plasma under the strong magnetic field
We study slow relaxation processes in the point vortex model for the
two-dimensional pure electron plasma under the strong magnetic field. By
numerical simulations, it is shown that, from an initial state, the system
undergoes the fast relaxation to a quasi-stationary state, and then goes
through the slow relaxation to reach a final state. From analysis of simulation
data, we find (i) the time scale of the slow relaxation increases linearly to
the number of electrons if it is measured by the unit of the bulk rotation
time, (ii) during the slow relaxation process, each electron undergoes an
superdiffusive motion, and (iii) the superdiffusive motion can be regarded as
the Levy flight, whose step size distribution is of the power law. The time
scale that each electron diffuses over the system size turns out to be much
shorter than that of the slow relaxation, which suggests that the correlation
among the superdiffusive trajectories is important in the slow relaxation
process.Comment: 11pages, 19 figures. Submitted to J. Phys. Soc. Jp
Sources of nonlinearities, chatter generation and suppression in metal cutting
The mechanics of chip formation has been revisited in order to understand functional relationships between the process and the technological parameters. This has led to the necessity of considering the chip-formation process as highly nonlinear, with complex interrelations between its dynamics and thermodynamics. In this paper a critical review of the state of the art of modelling and the experimental investigations is outlined with a view to how the nonlinear dynamics perception can help to capture the major phenomena causing instabilities (chatter) in machining operations. The paper is concluded with a case study, where stability of a milling process is investigated in detail, using an analytical model which results in an explicit relation for the stability limit. The model is very practical for the generation of the stability lobe diagrams, which is time consuming when using numerical methods. The extension of the model to the stability analysis of variable pitch cutting tools is also given. The application and verification of the method are demonstrated by several examples
Prolate spheroidal hematite particles equatorially belt with drug-carrying layered double hydroxide disks: Ring Nebula-like nanocomposites
A new nanocomposite architecture is reported which combines prolate spheroidal hematite nanoparticles with drug-carrying layered double hydroxide [LDH] disks in a single structure. Spindle-shaped hematite nanoparticles with average length of 225 nm and width of 75 nm were obtained by thermal decomposition of hydrothermally synthesized hematite. The particles were first coated with Mg-Al-NO3-LDH shell and then subjected to anion exchange with salicylate ions. The resulting bio-nanohybrid displayed a close structural resemblance to that of the Ring Nebula. Scanning electron microscope and transmission electron microscopy images showed that the LDH disks are stacked around the equatorial part of the ellipsoid extending along the main axis. This geometry possesses great structural tunability as the composition of the LDH and the nature of the interlayer region can be tailored and lead to novel applications in areas ranging from functional materials to medicine by encapsulating various guest molecules
Whatâs Sex (Composition) Got to Do with It? The Importance of Sex Composition of Gangs for Female and Male Membersâ Offending and Victimization
Sex composition of groups has been theorized in organizational sociology and found in prior work to structure female and male membersâ behaviors and experiences. Peer group and gang literature similarly finds that the sex gap in offending varies across groups of differing sex ratios. Drawing on this and other research linking gang membership, offending, and victimization, we examine whether sex composition of gangs is linked to sex differences in offending in this sample, further assess whether sex composition similarly structures femalesâ and malesâ victimization experiences, and if so, why. Self-report data from gang members in a multi-site, longitudinal study of 3,820 youths are employed. Results support previous findings about variations in member delinquency by both sex and sex composition of the gang and also indicate parallel variations in membersâ victimization. These results are further considered within the context of facilitating effects such as gender dynamics, gang characteristics, and normative orientation
The concept of "compartment allergy": prilocaine injected into different skin layers
We herein present a patient with delayed-type allergic hypersensitivity against prilocaine leading to spreading eczematous dermatitis after subcutaneous injections for local anesthesia with prilocaine. Prilocaine allergy was proven by positive skin testing and subcutaneous provocation, whereas the evaluation of other local anesthetics - among them lidocaine, articaine and mepivacaine - did not exhibit any evidence for cross-reactivity
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