2,874 research outputs found
The Limits of Government Regulation of Science
The recent controversy over the National Science Advisory Board for Biosecurity’s (NSABB) request that Science and Nature redact key parts of two papers on transmissible avian (H5N1) influenza reveal a troubled relationship between science and security. While NSABB’s request does not violate the First Amendment, efforts to censor the scientific press by force of law would usually be an unconstitutional prior restraint of the press absent a compelling state interest. The constitutional validity of conditions on grant funding to require pre-publication review of unclassified research is unclear but also arguably unconstitutional.
The clearest case where government may restrict publication is when research has been properly classified as a security risk. It is less clear whether government may suppress the publication of “controlled unclassified information” (CUI). The key inquiry is whether the information poses a genuine security risk and the restraint is the least restrictive alternative.
At the same time, the federal government has fairly broad latitude to protect sensitive data in its sole possession from disclosure under FOIA.
We propose that future decisions on dual-use research should be taken through a fair and transparent institutional review process, likely best modeled on the institutional biosafety committees required for recombinant DNA research
Science, Politics, and Values: The Politicization of Professional Practice Guidelines
The Connecticut Attorney General’s recent allegations that the Infectious Disease Society of America violated antitrust law through its treatment guidelines for Lyme disease were neither based in sound science or appropriate legal judgment. Strong scientific evidence favors IDSA’s position that chronic infection with the etiologic agent of Lyme disease does not occur in the absence of objective signs of ongoing infection and that long-term antibiotic use to treat dubious infection, recommended in the quasi-scientific guidelines put forth by the International Lyme and Associated Diseases Society (ILADS), are of no benefit. In siding with ILADS and other chronic Lyme disease advocates, ultimately forcing IDSA to settle lest it expend exorbitant legal costs, the attorney general abused science and his public trust. This case exemplifies the politicization of health policy and confuses the relative spheres inhabited by normative discourse and scientific inquiry. Science should provide the evidentiary base for normative discussions, and values and politics will always be important in deciding how science is applied for human benefit. But a wall of separation is needed between science, values, and politics, as medical science, and the patients who depend on it, is too important for political distortion
Virus Sharing, Genetic Sequencing, and Global Health Security
The WHO’s Pandemic Influenza Preparedness (PIP) Framework was a milestone global agreement designed to promote the international sharing of biological samples to develop vaccines, while that ensuring poorer countries would have access to those vaccines. Since the PIP Framework was negotiated, scientists have developed the capacity to use genetic sequencing data (GSD) to develop synthetic viruses rapidly for product development of life-saving technologies in a time-sensitive global emergency—threatening to unravel the Framework. Access to GSD may also have major implications for biosecurity, biosafety, and intellectual property (IP).
By rendering the physical transfer of viruses antiquated, GSD may also undermine the effectiveness of the PIP Framework itself, with disproportionate impacts on poorer countries. We examine the changes that need to be made to the PIP Framework to address the growing likelihood that GSD might be shared instead of physical virus samples. We also propose that the international community harness this opportunity to expand the scope of the PIP Framework beyond only influenza viruses with pandemic potential.
In light of non-influenza pandemic threats such as the Middle East Respiratory Syndrome (MERS) and Ebola, we call for an international agreement on the sharing of the benefits of research – such as vaccines and treatments – for other infectious diseases to ensure not only a more secure and healthy world, but also a more just world, for humanity
Interaction of two-dimensional transverse jet with a supersonic mainstream
The interaction of a two dimensional sonic jet injected transversely into a confined main flow was studied. The main flow consisted of air at a Mach number of 2.9. The effects of varying the jet parameters on the flow field were examined using surface pressure and composition data. Also, the downstream flow field was examined using static pressure, pitot pressure, and composition profile data. The jet parameters varied were gapwidth, jet static pressure, and injectant species of either helium or nitrogen. The values of the jet parameters used were 0.039, 0.056, and 0.109 cm for the gapwidth and 5, 10, and 20 for the jet to mainstream static pressure ratios. The features of the flow field produced by the mixing and interaction of the jet with the mainstream were related to the jet momentum. The data were used to demonstrate the validity of an existing two dimensional elliptic flow code
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with Seyfert 1s and Seyfert 2s
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and
1.9 galaxies over the 5-38 um region. We compare the spectral characteristics
of this sample to those of 58 Seyfert 1 and Seyfert 2 galaxies from the Spitzer
archives. An analysis of the spectral shapes, the silicate 10 um feature and
the emission line fluxes have enabled us to characterize the mid-IR properties
of Seyfert 1.8/1.9s. We find that the equivalent widths of the 10 um silicate
feature are generally weak in all Seyfert galaxies, as previously reported by
several studies. The few Seyfert galaxies in this sample that show deep 10 um
silicate absorption features are highly inclined and/or merging galaxies. It is
likely that these absorption features originate primarily in the dusty
interstellar medium of the host galaxy rather than in a dusty torus on parsec
scales close to the central engine. We find that the equivalent width of the
polycyclic aromatic hydrocarbon (PAH) band at 6.2 um correlates strongly with
the 20-30 um spectral index. Either of these quantities are good indicators of
the amount of starburst contribution to the mid-IR spectra. The spectra of
Seyfert 1.8 and 1.9s are dominated by these starburst features, similar to most
Seyfert 2s. They show strong PAH bands and a strong red continuum toward 30 um.
The strengths of the high-ionization forbidden narrow emission lines [O IV]
25.89 um, [Ne III] 15.56 um and [Ne V] 14.32 um relative to [Ne II] 12.81 um
are weaker in Seyfert 1.8/1.9s and Seyfert 2s as compared to Seyfert 1s. The
weakness of high-ionization lines in Seyfert 1.8-1.9s is suggestive of
intrinsically weak active galactic nuclei (AGN) continua, and/or stronger star
formation activity leading to enhanced [Ne II]. We discuss the implications of
these observational results in the context of the Unified Model of AGN.Comment: 36 pages, 4 tables, 6 figures, Accepted for publication in The
Astrophysical Journal, December 200
Diverging thermal expansion of the spin-ladder system (CHN)CuBr
We present high-resolution measurements of the -axis thermal
expansion and magnetostriction of piperidinium copper bromide \hp. The
experimental data at low temperatures is well accounted for by a two-leg
spin-ladder Hamiltonian. The thermal expansion shows a complex behaviour with
various sign changes and approaches a divergence at the critical
fields. All low-temperature features are semi-quantitatively explained within a
free fermion model; full quantitative agreement is obtained with Quantum Monte
Carlo simulations.Comment: 4 pages, 5 figures; version 2 is slightly shortened and typos are
correcte
A novel sodium phenylacetate-dextran derivative ester inhibits the growth and angiogenesis of MCF-7ras breast cancer xenografts
On the metallicity dependence of crystalline silicates in oxygen-rich asymptotic giant branch stars and red supergiants
We investigate the occurrence of crystalline silicates in oxygen-rich evolved
stars across a range of metallicities and mass-loss rates. It has been
suggested that the crystalline silicate feature strength increases with
increasing mass-loss rate, implying a correlation between lattice structure and
wind density. To test this, we analyse Spitzer IRS and Infrared Space
Observatory SWS spectra of 217 oxygen-rich asymptotic giant branch stars and 98
red supergiants in the Milky Way, the Large and Small Magellanic Clouds and
Galactic globular clusters. These encompass a range of spectral morphologies
from the spectrally-rich which exhibit a wealth of crystalline and amorphous
silicate features to 'naked' (dust-free) stars. We combine spectroscopic and
photometric observations with the GRAMS grid of radiative transfer models to
derive (dust) mass-loss rates and temperature. We then measure the strength of
the crystalline silicate bands at 23, 28 and 33 microns. We detect crystalline
silicates in stars with dust mass-loss rates which span over 3 dex, down to
rates of ~10^-9 solar masses/year. Detections of crystalline silicates are more
prevalent in higher mass-loss rate objects, though the highest mass-loss rate
objects do not show the 23-micron feature, possibly due to the low temperature
of the forsterite grains or it may indicate that the 23-micron band is going
into absorption due to high column density. Furthermore, we detect a change in
the crystalline silicate mineralogy with metallicity, with enstatite seen
increasingly at low metallicity.Comment: Accepted for publication in MNRAS, 24 pages, 16 figure
Narrow Components within the Fe Kalpha Profile of NGC 3516: Evidence for the Importance of General Relativistic Effects?
We present results from a simultaneous Chandra HETG and XMM-Newton
observation of NGC 3516. We find evidence for several narrow components of Fe
Kalpha along with a broad line. We consider the possibility that the lines
arise in an blob of material ejected from the nucleus with velocity ~0.25c. We
also consider an origin in a neutral accretion disk, suffering enhanced
illumination at 35 and 175 gravitational radii, perhaps due to magnetic
reconnection. The presence of these narrow features indicates there is no
Comptonizing region along the line-of-sight to the nucleus. This in turn is
compelling support for the hypothesis that broad Fe Kalpha components are, in
general, produced by strong gravity.Comment: 12 pages, 3 color figures. LaTeX with postscript figures. Resubmitted
June 7 2002, to Astrophysical Journal Letter
The soft X-ray and narrow-line emission of Mrk573 on kiloparcec scales
We present a study of the circumnuclear region of the nearby Seyfert galaxy
Mrk573 using Chandra, XMM-Newton and HST data. The X-ray morphology shows a
biconical region extending up to 12 arcsecs (4 kpc) in projection from the
nucleus. A strong correlation between the X-rays and the highly ionized gas
seen in the [O III] image is reported. Moreover, we have studied the line
intensities detected with the RGS/XMM-Newton and used them to fit the low
resolution EPIC/XMM-Newton and ACIS/Chandra spectra. The RGS spectrum is
dominated by emission lines of C VI, O VII, O VIII, Fe XVII, and Ne IX, among
others. A good fit is obtained using these emission lines found in the RGS
spectrum as a template for Chandra spectra of the nucleus and extended
emission. The photoionization model Cloudy provides a reasonable fit for both
the nuclear region and the cone-like structures. For the nucleus the emission
is modelled using two phases: a high ionization [log(U)=1.23] and a low
ionization [log(U)=0.13]. For the high ionization phase the transmitted and
reflected component are in a ratio 1:2, whereas for the low ionization the
reflected component dominates. For the extended emission, we successfully
reproduced the emission with two phases. The first phase shows a higher
ionization parameter for the NW (log(U)=0.9) than for the SE cone (log(U)=0.3).
The second phase shows a low ionization parameter (log(U)=-3) and is rather
uniform for NW and SE cones. In addition, the nuclear optical/infrared SED has
been modeled by a clumpy torus model. The torus bolometric luminosity agrees
with the AGN luminosity inferred from the observed hard X-ray spectrum. The
optical depth along the line of sight derived from the SED fit indicates a high
neutral column density in agreement with the classification of the nucleus as a
Compton-thick AGN.Comment: 15 pages, 14 figures, final version of the paper submitted to Ap
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