2,221 research outputs found
Holding the High Ground: The Operational Calculus of Torture and Coercive Interrogation
In Part I of this Article, we first consider some of the strengths and weaknesses of the partially adequate objections. In Part II, we explore torture in light of the biological distinction between pain and suffering and consider the implications of that distinction for our understanding of free will and the fighting spirit. Finally, in Part III, we suggest a more fundamental view of torture that navigates between the Scylla of naive moralizing and the Charybdis of ticking time-bombs. We propose that the debate should focus on torture\u27s effect on our country\u27s moral certainty, on the fighting spirit of our armed forces, and on our overall strategy in combating asymmetric foes and jihadist extremism. This notion of torture will cast an important part of the discussion in sharper relief while providing a clearer norm for those who make and execute policy to defend our nation from terrorism
Holding the High Ground: The Operational Calculus of Torture and Coercive Interrogation
In Part I of this Article, we first consider some of the strengths and weaknesses of the partially adequate objections. In Part II, we explore torture in light of the biological distinction between pain and suffering and consider the implications of that distinction for our understanding of free will and the fighting spirit. Finally, in Part III, we suggest a more fundamental view of torture that navigates between the Scylla of naive moralizing and the Charybdis of ticking time-bombs. We propose that the debate should focus on torture\u27s effect on our country\u27s moral certainty, on the fighting spirit of our armed forces, and on our overall strategy in combating asymmetric foes and jihadist extremism. This notion of torture will cast an important part of the discussion in sharper relief while providing a clearer norm for those who make and execute policy to defend our nation from terrorism
Hertzsprung-Russell diagram and mass distribution of barium stars
With the availability of parallaxes provided by the Tycho-Gaia Astrometric
Solution, it is possible to construct the Hertzsprung-Russell diagram (HRD) of
barium and related stars with unprecedented accuracy. A direct result from the
derived HRD is that subgiant CH stars occupy the same region as barium dwarfs,
contrary to what their designations imply. By comparing the position of barium
stars in the HRD with STAREVOL evolutionary tracks, it is possible to evaluate
their masses, provided the metallicity is known. We used an average metallicity
[Fe/H] = -0.25 and derived the mass distribution of barium giants. The
distribution peaks around 2.5 Msun with a tail at higher masses up to 4.5 Msun.
This peak is also seen in the mass distribution of a sample of normal K and M
giants used for comparison and is associated with stars located in the red
clump. When we compare these mass distributions, we see a deficit of low-mass
(1 - 2 Msun) barium giants. This is probably because low-mass stars reach large
radii at the tip of the red giant branch, which may have resulted in an early
binary interaction. Among barium giants, the high-mass tail is however
dominated by stars with barium indices of less than unity, based on a visual
inspection of the barium spectral line; that is, these stars have a very
moderate barium line strength. We believe that these stars are not genuine
barium giants, but rather bright giants, or supergiants, where the barium lines
are strengthened because of a positive luminosity effect. Moreover, contrary to
previous claims, we do not see differences between the mass distributions of
mild and strong barium giants.Comment: 14 pages, 17 figure
Millimeter wave surface resistance of RBa2Cu3O(7-delta) (R=Y,Eu,Dy,Sm,Er) superconductors
The measurements are reported of the millimeter wave surface resistance R(sub s) at 58.6 GHz of bulk samples of RBa2Cu3O(7-delta) (R = Y,Eu,Dy,Sm,Er) and of YBa2Cu3O(7-delta) superconducting films, in the temperature range from 20 to 300 K. The bulk samples were prepared by cold pressing the powders of RBa2Cu3O(7-delta) into one in. disks. The powders were prepared by several sinterings in one atmosphere of oxygen at 925 C, with grindings between sinterings, to obtain the superconducting phase. The thin films were deposited on SrTiO3 and LaGaO3 substrates by pulsed laser ablation. Each sample was measured by replacing the end wall of a gold-plated Te sub 013 circular mode copper cavity with the sample and determining the cavity quality factor . From the difference in the Q-factor of the cavity, with and without the sample, the R(sub s) of the sample was determined
Performance evaluation of several well-known and new scintillators for MeV X-ray imaging
International audienceDigital X-ray imaging systems for MeV range photon beams are based on a combination of a scintillator screen and either a camera or an amorphous silicon array. To limit dose rate on electronics and enhance imaging device lifetime, the scintillator screen is mirror-coupled to the camera. Performances of such devices are a compromise between exposure time and spatial resolution. These technical characteristics are especially scintillator dependent. In this paper, we present a performance evaluation of six different scintillators with a 9 MeV Bremsstrahlung X-ray source. The tested scintillators are composed of one micro-structured CsI(Tl) scintillator, two phosphor (GOS) screens and three transparent scintillators. These scintillators present a wide range of density, thickness and conversion efficiency. Each scintillator's performance is assessed based on the combination of light output (ADU number) and modulation transfer function (spatial resolution) obtained. The results are helpful to guide design and engineering of high energy imaging devices adapted to specific requirements
Discovery of a TiO emission band in the infrared spectrum of the S star NP Aurigae
We report on the discovery of an infrared emission band in the Spitzer
spectrum of the S-type AGB star NP Aurigae that is caused by TiO molecules in
the circumstellar environment. We modelled the observed emission to derive the
temperature of the TiO molecules (\approx 600 K), an upper limit on the column
density (\approx 10^17.25 cm^{-2}) and a lower limit on the spatial extent of
the layer that contains these molecules. (\approx 4.6 stellar radii). This is
the first time that this TiO emission band is observed. A search for similar
emission features in the sample of S-type stars yielded two additional
candidates. However, owing to the additional dust emission, the identification
is less stringent. By comparing the stellar characteristics of NP Aur to those
of the other stars in our sample, we find that all stars with TiO emission show
large-amplitude pulsations, s-process enrichment, and a low C/O ratio. These
characteristics might be necessary requirements for a star to show TiO in
emission, but they are not sufficient.Comment: 4 pages, 4 figures, letter to the edito
Li-rich K giants, dust excess, and binarity
The origin of the Li-rich K giants is still highly debated. Here, we
investigate the incidence of binarity among this family from a nine-year
radial-velocity monitoring of a sample of 11 Li-rich K giants using the HERMES
spectrograph attached to the 1.2m Mercator telescope. A sample of 13
non-Li-rich giants (8 of them being surrounded by dust according to IRAS, WISE,
and ISO data) was monitored alongside. When compared to the binary frequency in
a reference sample of 190 K giants (containing 17.4% of definite spectroscopic
binaries -- SB -- and 6.3% of possible spectroscopic binaries -- SB?), the
binary frequency appears normal among the Li-rich giants (2/11 definite
binaries plus 2 possible binaries, or 18.2% SB + 18.2% SB?), after taking
account of the small sample size through the hypergeometric probability
distribution. Therefore, there appears to be no causal relationship between Li
enrichment and binarity. Moreover, there is no correlation between Li
enrichment and the presence of circumstellar dust, and the only correlation
that could be found between Li enrichment and rapid rotation is that the most
Li-enriched K giants appear to be fast-rotating stars. However, among the dusty
K giants, the binary frequency is much higher (4/8 definite binaries plus 1
possible binary). The remaining 3 dusty K giants suffer from a radial-velocity
jitter, as is expected for the most luminous K giants, which these are
The Lie derivative of spinor fields: theory and applications
Starting from the general concept of a Lie derivative of an arbitrary
differentiable map, we develop a systematic theory of Lie differentiation in
the framework of reductive G-structures P on a principal bundle Q. It is shown
that these structures admit a canonical decomposition of the pull-back vector
bundle i_P^*(TQ) = P\times_Q TQ over P. For classical G-structures, i.e.
reductive G-subbundles of the linear frame bundle, such a decomposition defines
an infinitesimal canonical lift. This lift extends to a prolongation
Gamma-structure on P. In this general geometric framework the concept of a Lie
derivative of spinor fields is reviewed. On specializing to the case of the
Kosmann lift, we recover Kosmann's original definition. We also show that in
the case of a reductive G-structure one can introduce a "reductive Lie
derivative" with respect to a certain class of generalized infinitesimal
automorphisms, and, as an interesting by-product, prove a result due to
Bourguignon and Gauduchon in a more general manner. Next, we give a new
characterization as well as a generalization of the Killing equation, and
propose a geometric reinterpretation of Penrose's Lie derivative of "spinor
fields". Finally, we present an important application of the theory of the Lie
derivative of spinor fields to the calculus of variations.Comment: 28 pages, 1 figur
“If my family is happy, then I am happy”: Quality-of-life determinants of parents of school-age children
Objective:
Obesity is a public health concern for children and adults and effective obesity prevention programming is needed urgently. The effectiveness of health-related messaging and interventions is influenced by the way content is framed. HomeStyles is an obesity prevention program, which aims to promote health through the frame of improved quality of life. Methods:
Thus, focus groups were conducted with English- and Spanish-speaking parents of school-aged children (ages 6–11) to identify key quality-of-life determinants as described by parents. Results:
Parents (n = 158) reported that their quality of life was influenced by family happiness and parent and child health (e.g. adequate sleep, exercise, healthy diet). Many parents expressed that their busy schedules and lack of family time were detrimental to their quality of life. Work–life balance and financial stability were other factors commonly noted to impact quality of life. Spanish-speaking parents also reported being undocumented and feeling a lack of a sense of community negatively influenced their quality of life. Conclusion:
Considering parent-defined quality-of-life determinants when framing health-related messaging and developing interventions may increase participant interest and ultimately improve health-related behaviors. Next steps in the HomeStyles project include using parent-reported quality-of-life determinants to guide the development of intervention materials
Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars
Among Carbon-Enhanced Metal-Poor (CEMP) stars, some are found to be enriched
in s-process elements (CEMP-s), in r-process elements (CEMP-r) or in both s-
and r-process elements (CEMP-rs). The origin of the abundance differences
between CEMP-s and CEMP-rs stars is presently unknown. It has been claimed that
the i-process, whose site still remains to be identified, could better
reproduce CEMP-rs abundances than the s-process. We analyze high-resolution
spectra of 25 metal-poor stars, observed with the high-resolution HERMES
spectrograph mounted on the Mercator telescope, La Palma, or with the UVES/VLT
and HIRES/KECK spectrographs. We propose a new, robust classification method
for CEMP-s and CEMP-rs stars using eight heavy element abundances. The
abundance profiles of CEMP-s and CEMP-rs stars are derived and there appears to
be an abundance continuum between the two stellar classes. CEMP-rs stars
present most of the characteristics of extrinsic stars such as CEMP-s, CH,
Barium and extrinsic S stars, with an even larger binarity rate among CEMP-rs
stars than among CEMP-s stars. Stellar evolutionary tracks of an enhanced
carbon composition (consistent with our abundance determinations) are necessary
to explain the position of CEMP-s and CEMP-rs stars in the HR diagram using
Gaia DR2 parallaxes; they are found to lie mostly on the RGB. CEMP-rs stars can
be explained as being polluted by a low-mass, low-metallicity TP-AGB companion
experiencing i-process nucleosynthesis after proton ingestion during its first
convective thermal pulses. The global fitting of our i-process models to
CEMP-rs stars is as good as the one of our s-process models to CEMP-s stars. As
such, CEMP-rs stars could be renamed as CEMP-sr stars, since they represent a
particular manifestation of the s-process at low-metallicities. For these
objects a call for an exotic i-process site may not necessarily be required
anymore.Comment: 35 pages, 26 figures, Accepted for publication in A&A, Final versio
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