1,676 research outputs found

    Deliberative Constitutionalism in the National Security Setting

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    Deliberative democracy theory maintains that authentic deliberation about matters of public concern is an essential condition for the legitimacy of political decisions. Such deliberation has two features. The first is deliberative rigor. This is deliberation guided by public-regarding reasons in a process in which persons are genuinely open to the force of the better argument. The second is transparency. This requires that requires that officials publicly explain the reasons for their decisions in terms that citizens can endorse as acceptable grounds for acting in the name of the political community. Such requirements would seem to be especially important in the national security setting, where decisions can have profound life-and-death consequences. Yet this is the setting in which transparency often is least feasible on the part of the Executive branch. Officials may be constrained for good reasons from fully explaining the bases for their decisions. While such reason-giving is especially important to the perceived legitimacy of a decision, anticipating the need to provide it also can enhance deliberative rigor. Limited transparency thus creates the risk both that crucial decisions may not be regarded as legitimate, and that the deliberative process will not be as robust as it should be. In this chapter, we argue that ensuring robust internal deliberative processes in the national security setting can compensate at least to some degree for this limitation. Appreciating the demands of deliberative democracy theory can help inform this process by illuminating how various procedural mechanisms may promote the goals that transparency purports to serve. We focus on the Lawyers Group, which includes senior national security lawyers from across the government, as an example of an arrangement that can help further the ends of deliberative democracy by providing a vehicle for deliberation that meets many, even if not all, of the requirements of that theory. Coordinated by the legal advisor for the National Security Council, this group discusses national security issues that will be presented to the President. We regard our analysis as contributing in two ways to deliberative democratic theory. First, it focuses on the possibility of satisfying the requirement of this theory in a setting in which decision-making often falls short of the demands of full transparency. Second, it suggests how legal analysis may play a distinctive role in the deliberative process. There are limits to what the Lawyers Group can accomplish. We believe, however, that it should be assessed in terms of its contribution to the larger national security deliberative system of which it is a part. From this perspective, the Group’s compliance with several prescriptions of deliberative theory helps it strengthen, even if it does not guarantee, the rigor and persuasiveness of the justifications that the President is able to provide for national security decisions

    Electrically monitoring DNA repair by photolyase

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    Cyclobutane pyrimidine dimers are the major DNA photoproducts produced upon exposure to UV radiation. If left unrepaired, these lesions can lead to replication errors, mutation, and cell death. Photolyase is a light-activated flavoenzyme that binds to pyrimidine dimers in DNA and repairs them in a reaction triggered by electron transfer from the photoexcited flavin cofactor to the dimer. Using gold electrodes modified with DNA duplexes containing a cyclobutane thymine dimer (T T), here we probe the electrochemistry of the flavin cofactor in Escherichia coli photolyase. Cyclic and square-wave voltammograms of photolyase deposited on these electrodes show a redox signal at 40 mV versus normal hydrogen electrode, consistent with electron transfer to and from the flavin in the DNA-bound protein. This signal is dramatically attenuated on surfaces where the pi-stacking of the DNA bases is perturbed by the presence of an abasic site below the T T, an indication that the redox pathway is DNA-mediated. DNA repair can, moreover, be monitored electrically. Exposure of photolyase on T T-damaged DNA films to near-UV/blue light leads to changes in the flavin signal consistent with repair, as confirmed by parallel HPLC experiments. These results demonstrate the exquisite sensitivity of DNA electrochemistry to perturbations in base pair stacking and the applicability of this chemistry to probe reactions of proteins with DNA

    Using Coronal Loops to Reconstruct the Magnetic Field of an Active Region Before and After a Major Flare

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    The shapes of solar coronal loops are sensitive to the presence of electrical currents that are the carriers of the nonpotential energy available for impulsive activity. We use this information in a new method for modeling the coronal magnetic field of AR 11158 as a nonlinear force-free field (NLFFF). The observations used are coronal images around time of major flare activity on 2011/02/15, together with the surface line-of-sight magnetic field measurements. The data are from the Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly (HMI and AIA, respectively) onboard the Solar Dynamics Observatory (SDO). The model fields are constrained to approximate the coronal loop configurations as closely as possible, while also subject to the force-free constraints. The method does not use transverse photospheric magnetic field components as input, and is thereby distinct from methods for modeling NLFFFs based on photospheric vector magnetograms. We validate the method using observations of AR 11158 at a time well before major flaring, and subsequently review the field evolution just prior to and following an X2.2 flare and associated eruption. The models indicate that the energy released during the instability is about 1×10321\times10^{32} erg, consistent with what is needed to power such a large eruptive flare. Immediately prior to the eruption the model field contains a compact sigmoid bundle of twisted flux that is not present in the post-eruption models, which is consistent with the observations. The core of that model structure is twisted by 0.9\approx0.9 full turns about its axis.Comment: ApJ, in pres

    Oscar Wilde\u27s Fiction: Views on Life and Art

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    Oscar Wilde depicts different views on life and art. The stories selected have common themes of wealth (monetary/non-monatary), love, devotion, self-destruction and death:: The Picture of Dorian Gray, The Happy Prince, The Devoted Friend, The Selfish Giant, and The Rose and the Nightingale. These four fairy tales tie in nicely with Wilde\u27s novel to show the true value of life and art

    Selection and Characterization of a Novel DNA Aptamer for Label-Free Fluorescence Biosensing of Ochratoxin A

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    Nucleic acid aptamers are emerging as useful molecular recognition tools for food safety monitoring. However, practical and technical challenges limit the number and diversity of available aptamer probes that can be incorporated into novel sensing schemes. This work describes the selection of novel DNA aptamers that bind to the important food contaminant ochratoxin A (OTA). Following 15 rounds of in vitro selection, sequences were analyzed for OTA binding. Two of the isolated aptamers demonstrated high affinity binding and selectivity to this mycotoxin compared to similar food adulterants. These sequences, as well as a truncated aptamer (minimal sequence required for binding), were incorporated into a SYBR® Green I fluorescence-based OTA biosensing scheme. This label-free detection platform is capable of rapid, selective, and sensitive OTA quantification with a limit of detection of 9 nM and linear quantification up to 100 nM

    A Method for Data-Driven Simulations of Evolving Solar Active Regions

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    We present a method for performing data-driven simulations of solar active region formation and evolution. The approach is based on magnetofriction, which evolves the induction equation assuming the plasma velocity is proportional to the Lorentz force. The simulations of active region coronal field are driven by temporal sequences of photospheric magnetograms from the Helioseismic Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO). Under certain conditions, the data-driven simulations produce flux ropes that are ejected from the modeled active region due to loss of equilibrium. Following the ejection of flux ropes, we find an enhancement of the photospheric horizontal field near the polarity inversion line. We also present a method for the synthesis of mock coronal images based on a proxy emissivity calculated from the current density distribution in the model. This method yields mock coronal images that are somewhat reminiscent of images of active regions taken by instruments such as SDO's Atmospheric Imaging Assembly (AIA) at extreme ultraviolet wavelengths.Comment: Accepted to ApJ; comments/questions related to this article are welcome via e-mail, even after publicatio

    Challenges and Opportunities for Small Molecule Aptamer Development

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    Aptamers are single-stranded oligonucleotides that bind to targets with high affinity and selectivity. Their use as molecular recognition elements has emerged as a viable approach for biosensing, diagnostics, and therapeutics. Despite this potential, relatively few aptamers exist that bind to small molecules. Small molecules are important targets for investigation due to their diverse biological functions as well as their clinical and commercial uses. Novel, effective molecular recognition probes for these compounds are therefore of great interest. This paper will highlight the technical challenges of aptamer development for small molecule targets, as well as the opportunities that exist for their application in biosensing and chemical biology
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