13,074 research outputs found
Opening up terrorism talk: The sequential and categorical production of discursive power within the call openings of a talk radio broadcast
The current research undertakes a combined CA/MCA approach to analyse the unfolding moral business of ‘talk radio’ discourse, and situates this analysis within a critical discourse studies framework. In a case study analysis of a talk radio broadcast on the topic of terrorism, the sequencing and membership categorization work that is accomplished during the call openings of its contributors is examined. Local manifestations of discursive power allied to the ‘host’ role are identified, along with the data-driven distinction of ‘lay’ and ‘elite’ callers. The empowering versus disempowering consequences of sequential turn allocation and identity categorization are explored, leading to some reflections on security versus human rights advocacy within terrorism talk. The contribution of this research to two research enterprises is then outlined. Firstly, we highlight the benefit that a combined CA/MCA approach, which foregrounds powerplay, offers to analysis of talk-in-interaction. Following which, we underline how placing such a micro-level spotlight on the seemingly mundane details of talk in context can offer valuable insights for critical terrorism studies
Physiological Aspects of Genetics
A considerable amount of evidence indicates that desoxyribonucleic acid is capable of duplicating itself, a property also possessed by genes. (By a self-duplicating material, we mean one which plays some essential role in its own production.) Watson & Crick (1) have proposed a new structure for desoxyribonucleic acid which not only takes into account the existing analytical and x-ray diffraction data but also seems capable of explaining the mechanism of duplication. Their model consists of two helical chains coiled around the same axis, the purine and pyrimidine bases on the inside, the phosphate groups on the outside. The chains are held together by hydrogen bonds between the bases, the adenine residues of either chain being bonded specifically to thymine in the other, and similarly guanine to cytosine. The sequence of bases along one chain is not restricted, but once fixed the sequence along the other chain is determined. This complementarity, which is the most novel feature of the structure, suggests that duplication takes place by separation of the two chains, followed by the synthesis of its complement alongside each chain. The model is supported by recent x-ray diffraction studies (2, 3)
Reconstructing Small Scale Lenses from the Cosmic Microwave Background Temperature Fluctuations
Cosmic Microwave Background (CMB) lensing is a powerful probe of the matter
distribution in the Universe. The standard quadratic estimator, which is
typically used to measure the lensing signal, is known to be suboptimal for
low-noise polarization data from next-generation experiments. In this paper we
explain why the quadratic estimator will also be suboptimal for measuring
lensing on very small scales, even for measurements in temperature where this
estimator typically performs well. Though maximum likelihood methods could be
implemented to improve performance, we explore a much simpler solution,
revisiting a previously proposed method to measure lensing which involves a
direct inversion of the background gradient. An important application of this
simple formalism is the measurement of cluster masses with CMB lensing. We find
that directly applying a gradient inversion matched filter to simulated lensed
images of the CMB can tighten constraints on cluster masses compared to the
quadratic estimator. While the difference is not relevant for existing surveys,
for future surveys it can translate to significant improvements in mass
calibration for distant clusters, where galaxy lensing calibration is
ineffective due to the lack of enough resolved background galaxies.
Improvements can be as large as for a cluster at and a
next-generation CMB experiment with 1K-arcmin noise, and over an order of
magnitude for lower noise levels. For future surveys, this simple
matched-filter or gradient inversion method approaches the performance of
maximum likelihood methods, at a fraction of the computational cost.Comment: 11 pages, 7 figure
Impact of spin-orbit currents on the electroweak skin of neutron-rich nuclei
Background: Measurements of neutron radii provide important constraints on
the isovector sector of nuclear density functionals and offer vital guidance in
areas as diverse as atomic parity violation, heavy-ion collisions, and
neutron-star structure. Purpose: To assess the impact of spin-orbit currents on
the electromagnetic- and weak-charge radii of a variety of nuclei. Special
emphasis is placed on the experimentally accessible electroweak skin, defined
as the difference between weak-charge and electromagnetic-charge radii.
Methods: Two accurately calibrated relativistic mean field models are used to
compute proton, neutron, charge, and weak-charge radii of a variety of nuclei.
Results: We find that spin-orbit contributions to the electroweak skin of light
neutron-rich nuclei, such as 22O and 48Ca, are significant and result in a
substantial increase in the size of the electroweak skin relative to the
neutron skin. Conclusions: Given that spin-orbit contributions to both the
charge and weak-charge radii of nuclei are often as large as present or
anticipated experimental error bars, future calculations must incorporate
spin-orbit currents in the calculation of electroweak form factors.Comment: 17 pages, 2 figures, and 2 table
Lipase inhibition attenuates the acute inhibitory effects of oral fat on food intake in healthy subjects
The lipase inhibitor, orlistat, is used in the treatment of obesity and reduces fat absorption by about 30%. However, the mean weight loss induced by orlistat is less than expected for the degree of fat malabsorption. It was hypothesised that lipase inhibition with orlistat attenuates the suppressive effects of oral fat on subsequent energy intake in normal-weight subjects. Fourteen healthy, lean subjects (nine males, five females; aged 25 +/- 1.3 years) were studied twice, in a double-blind fashion. The subjects received a high-fat yoghurt 'preload' (males 400 g (2562 kJ); females 300 g (1923 kJ)), containing orlistat (120 mg) on one study day (and no orlistat on the other 'control' day), 30 min before ad libitum access to food and drinks; energy intake was assessed during the following 8 h. Blood samples were taken at regular intervals for the measurement of plasma cholecystokinin (CCK). Each subject performed a 3 d faecal fat collection following each study. Energy intake during the day was greater following orlistat (10,220 (SEM 928) kJ) v. control (9405 (SEM 824) kJ) (P=0.02). On both days plasma CCK increased (P<0.05) after the preload. Plasma CCK 20 min following ingestion of the preload was less after orlistat (4.1 (SEM 0.9) pmol/l) v. control (5.3 (SEM 0.9) pmol/l (P=0.028); however there was no difference in the area under the curve 0-510 min between the two study days. Fat excretion was greater following orlistat (1017 (SEM 168) kJ) v. control (484 (SEM 90) kJ) (P=0.004). In conclusion, in healthy, lean subjects the acute inhibitory effect of fat on subsequent energy intake is attenuated by orlistat and the increase in energy intake approximates the energy lost due to fat malabsorption.Deirdre O’Donovan, Christine Feinle-Bisset, Judith Wishart and Michael Horowit
Analysis of flux-integrated cross sections for quasi-elastic neutrino charged-current scattering off C at MiniBooNE energies
Flux-averaged and flux-integrated cross sections for quasi-elastic neutrino
charged-current scattering on nucleus are analyzed. It is shown that the
flux-integrated differential cross sections are nuclear model-independent. We
calculate these cross sections using the relativistic distorted-wave impulse
approximation and relativistic Fermi gas model with the Booster Neutrino
Beamline flux and compare results with the recent MiniBooNE experiment data.
Within these models an axial mass is extracted from a fit of the measured
cross section. The extracted value of is consistent with
the MiniBooNE result. The measured and calculated double differential cross
sections generally agree within the error of the
experiment. But the Fermi gas model predictions are completely off of the data
in the region of low muon energies and scattering angles.Comment: 23 pages, 8 figure
Characterization of Optimized Si-MOSFETs for Terahertz Detection
Research into components needed to utilize the THz region of the electromagnetic spectrum has recently gained more attention due to advances in semiconductor technology and materials science. These advances have led to the desire of create CMOS focal plane arrays (FPA) for THz imaging in a range of applications such as astronomy, security, earth science, industry, and communications. Si-MOSFETs are being investigated as the sensing node in THz FPAs due to their ability to detect THz and their ease of integration into the CMOS process facilitating the fabrication of large format arrays. To investigate the performance of devices fabricated at a commercial foundry, a test chip containing MOSFETs with appropriately sized dipole bowtie antennae were fabricated using a 0.35 micron CMOS process. A number of fabrication parameters were varied including both MOSFET geometry and antenna design to investigate optimizing detection for the 200 GHz atmospheric window. To test these devices an experimental low noise setup comprising of a lock-in amplifier, low noise current pre-amplifier, and various low noise techniques has been assembled. Different biasing conditions and temperature were used to analyze the mechanisms of detection and find the best operating parameters. The devices that implemented a 2 µm source extension, and antennae attached to the source and gate region yielded the largest response to 200 GHz incident radiation. The peak THz response varied little between room temperature and when cooled to 130K. Responsivities as high as 4.5 mA/W were measured and NEP as low as 6 nW/√Hz were achieved at room temperature. These results show agreement with other works regarding THz response to temperature and different biasing conditions
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Support during birth interacts with prior trauma and birth intervention to predict postnatal post-traumatic stress symptoms
Background: Many women experience childbirth as traumatic and 2% develop post-traumatic stress disorder (PTSD). This study examined the role of health practitioner support and personal control during birth as predictors of PTS symptoms, adjusting for vulnerability factors of prior trauma, depression, control beliefs and birth intervention. It also investigated interactions between support, prior trauma and birth intervention and their association with PTS symptoms.
Methods: A prospective longitudinal survey of 138 women recruited from UK NHS maternity clinics. Measures were taken in pregnancy, three-weeks and three-months after the birth.
Results: Support and control during birth were not predictive of postnatal PTS symptoms. However, support was predictive of PTS symptoms in a subset of women with prior trauma (beta = -.41, R2 = 16%) at both three-weeks and three-months postpartum. The interaction of birth intervention and support was associated with PTS symptoms three-months after birth, the relationship between support and PTS symptoms was stronger in women experiencing more intervention.
Conclusions: Low support from health practitioners is predictive of postnatal PTS symptoms in women who have a history of trauma. Longer-term effects of low support on postnatal PTS symptoms are also found in women who had more intervention during birth
The Vector Analyzing Power in Elastic Electron-Nucleus Scattering
The vector analyzing power A_n is calculated for elastic electron scattering
from a variety of spin zero nuclei at energies from 14 MeV to 3 GeV. Time
reversal symmetry insures that A_n vanish in first Born approximation.
Therefore A_n depends on Coulomb distortions and can be large for scattering
from heavy nuclei. The vector analyzing power is a potential source of
systematic error for parity violation experiments. We find that A_n=-0.361 ppm
for the kinematics of the Parity Radius Experiment (PREX) involving 850 MeV
electrons scattering at six degrees from 208Pb. This is comparable to the
parity violating asymmetry. However for HAPPEX He involving 3 GeV electrons
scattering on 4He we find that A_n is very small.Comment: 6 pages, 6 figures, submitted to Phys. Rev.
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