1,322 research outputs found
Development of biostereometric experiments
The stereometric camera was designed for close-range techniques in biostereometrics. The camera focusing distance of 360 mm to infinity covers a broad field of close-range photogrammetry. The design provides for a separate unit for the lens system and interchangeable backs on the camera for the use of single frame film exposure, roll-type film cassettes, or glass plates. The system incorporates the use of a surface contrast optical projector
Stereometric body volume measurement
The following studies are reported: (1) effects of extended space flight on body form of Skylab astronauts using biostereometrics; (2) comparison of body volume determinations using hydrostatic weighing and biostereometrics; and (3) training of technicians in biostereometric principles and procedures
Advanced Diagnostics for the Study of Linearly Polarized Emission. II: Application to Diffuse Interstellar Radio Synchrotron Emission
Diagnostics of polarized emission provide us with valuable information on the
Galactic magnetic field and the state of turbulence in the interstellar medium,
which cannot be obtained from synchrotron intensity alone. In Paper I (Herron
et al. 2017b), we derived polarization diagnostics that are rotationally and
translationally invariant in the - plane, similar to the polarization
gradient. In this paper, we apply these diagnostics to simulations of ideal
magnetohydrodynamic turbulence that have a range of sonic and Alfv\'enic Mach
numbers. We generate synthetic images of Stokes and for these
simulations, for the cases where the turbulence is illuminated from behind by
uniform polarized emission, and where the polarized emission originates from
within the turbulent volume. From these simulated images we calculate the
polarization diagnostics derived in Paper I, for different lines of sight
relative to the mean magnetic field, and for a range of frequencies. For all of
our simulations, we find that the polarization gradient is very similar to the
generalized polarization gradient, and that both trace spatial variations in
the magnetoionic medium for the case where emission originates within the
turbulent volume, provided that the medium is not supersonic. We propose a
method for distinguishing the cases of emission coming from behind or within a
turbulent, Faraday rotating medium, and a method to partly map the rotation
measure of the observed region. We also speculate on statistics of these
diagnostics that may allow us to constrain the physical properties of an
observed turbulent region.Comment: 34 pages, 25 figures, accepted for publication in Ap
Polarization Gradient Study of Interstellar Medium Turbulence Using The Canadian Galactic Plane Survey
We have investigated the magneto-ionic turbulence in the interstellar medium
through spatial gradients of the complex radio polarization vector in the
Canadian Galactic Plane Survey (CGPS). The CGPS data cover 1300 square-degrees,
over the range ,
with an extension to
in the range , and arcminute
resolution at 1420 MHz. Previous studies found a correlation between the
skewness and kurtosis of the polarization gradient and the Mach number of the
turbulence, or assumed this correlation to deduce the Mach number of an
observed turbulent region. We present polarization gradient images of the
entire CGPS dataset, and analyze the dependence of these images on angular
resolution. The polarization gradients are filamentary, and the length of these
filaments is largest towards the Galactic anti-center, and smallest towards the
inner Galaxy. This may imply that small-scale turbulence is stronger in the
inner Galaxy, or that we observe more distant features at low Galactic
longitudes. For every resolution studied, the skewness of the polarization
gradient is influenced by the edges of bright polarization gradient regions,
which are not related to the turbulence revealed by the polarization gradients.
We also find that the skewness of the polarization gradient is sensitive to the
size of the box used to calculate the skewness, but insensitive to Galactic
longitude, implying that the skewness only probes the number and magnitude of
the inhomogeneities within the box. We conclude that the skewness and kurtosis
of the polarization gradient are not ideal statistics for probing natural
magneto-ionic turbulence.Comment: 21 pages, 15 figures, accepted by Ap
Review of Pioneers of Quantum Chemistry
There is little doubt that reading books other than textbooks represents an important component of maintaining knowledge for many chemistry educators. Nonetheless, with 30 or more books a year being produced by the ACS Symposium Series alone, how can choices be made about what merits reading time? Certainly, the presentation of current research trends that might influence the chemistry taught in courses represents one metric, but there are many additional worthy books. In terms of potential teaching treasures to be mined, time spent reading history of science presents a strong possibility
Survey of Photochemical and Rate Data for Twentyâeight Reactions of Interest in Atmospheric Chemistry
Photochemical and rate data have been evaluated for 28 gas phase reactions of interest for the chemistry of the stratosphere. The results are presented on data sheets, one per reaction. For each reaction, the available data are summarized. Where possible there is given a preferred value for the rate constant or, for the photochemical reactions, preferred values for primary quantum yields and optical absorption coefficients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87745/2/267_1.pd
The ISLE corpus of non-native spoken English
For the purpose of developing pronunciation training tools for second language learning a corpus of non-native speech data has been collected, which consists of almost 18 hours of annotated speech signals spoken by Italian and German learners of English. The corpus is based on 250 utterances selected from typical second language learning exercises. It has been annotated at the word and the phone level, to highlight pronunciation errors such as phone realisation problems and misplaced word stress assignments. The data has been used to develop and evaluate several diagnostic components, which can be used to produce corrective feedback of unprecedented detail to a language learner
Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach
The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor
diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported.
The nanodispersed materials obtained show quantum size effects in their optical spectra
and exhibit near band-edge luminescence. The influence of experimental parameters on
the properties of the nanocrystallites is discussed. HRTEM images of these materials show
well-defined, crystalline nanosized particles. Standard size fractionation procedures can
be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS
and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2Âą-bipyrimidine,
are used as the starting materials for the preparation of novel nanocomposites. The optical
properties shown by these new nanocomposites are compared with those of the starting
nanodispersed materials
The Co-occurrence of child and intimate partner maltreatment in the family: characteristics of the violent perpetrators
This study considers the characteristics associated with mothers and fathers who maltreat their child and each other in comparison to parents who only maltreat their child. One hundred and sixty-two parents who had allegations of child maltreatment made against them were considered. The sample consisted of 43 fathers (Paternal FamilyâPF) and 23 mothers (Maternal FamilyâMF) who perpetrated both partner and child maltreatment, together with 23 fathers (Paternal ChildâPC) and 26 mothers (Maternal ChildâMC) who perpetrated child maltreatment only. In addition, 2 fathers (Paternal VictimâPV) and 23 mothers (Maternal VictimâMV) were victims of intimate partner maltreatment and perpetrators of child maltreatment and 7 fathers (Paternal Non-abusive CarerâPNC) and 15 mothers (Maternal Non-abusive CarerâMNC) did not maltreat the child but lived with an individual who did. Within their family unit, 40.7% of parents perpetrated both intimate partner and child maltreatment. However, fathers were significantly more likely to maltreat both their partner and child than mothers and mothers were significantly more likely to be victims of intimate partner violence than fathers. PF fathers conducted the highest amount of physical and/or sexual child maltreatment while MC and MV mothers perpetrated the highest amount of child neglect. Few significant differences between mothers were found. PF fathers had significantly more factors associated with development of a criminogenic lifestyle than PC fathers. Marked sex differences were demonstrated with PF fathers demonstrating significantly more antisocial characteristics, less mental health problems and fewer feelings of isolation than MF mothers. MC mothers had significantly more childhood abuse, mental health problems, parenting risk factors and were significantly more likely to be biologically related to the child than PC fathers. This study suggests that violent families should be assessed and treated in a holistic manner, considering the effects of partner violence upon all family members, rather than exclusively intervening with the violent man
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