2,841 research outputs found
Responding to Cybersecurity Challenges: Securing Vulnerable U.S. Emergency Alert Systems
Emergency alert systems (EASs) in the United States (US) form part of the nation’s critical infrastructure. These systems rely on aging platforms and suffer from a fragmented interconnected network of partnerships. Some EASs have an easily identifiable vulnerability: one can access their management website via the Internet. Authorities must secure these systems quickly. Other concerns also exist, such as the lack of policies for reporting vulnerabilities. To begin to assess EASs in the US, we used Shodan to evaluate the availability of these websites in six southeastern states. We found 18 such websites that one could access via the Internet and that required only requiring user credentials to login into. Next, we searched for published policies on reporting vulnerabilities; we found no vulnerability-disclosure policies for any system we identified. To identify, prioritize, and address EAS vulnerabilities, we present a list of technical and management strategies to reduce cybersecurity threats. We recommend integrated policies and procedures at all levels of the public-private-government partnerships and system resilience as lines of defense against cybersecurity threats. By implementing these strategies, EASs in the US will be positioned to update critical infrastructure, notify groups of emergencies, and ensure the distribution of valid and reliable information to at-risk populations
Heteroclinic intersections between Invariant Circles of Volume-Preserving Maps
We develop a Melnikov method for volume-preserving maps with codimension one
invariant manifolds. The Melnikov function is shown to be related to the flux
of the perturbation through the unperturbed invariant surface. As an example,
we compute the Melnikov function for a perturbation of a three-dimensional map
that has a heteroclinic connection between a pair of invariant circles. The
intersection curves of the manifolds are shown to undergo bifurcations in
homologyComment: LaTex with 10 eps figure
Droplets Transport in a Microfluidic Chip for In Vitro Compartmentalisation
In vitro compartmentalisation is an emerging technology for protein evolution and selection. In this presentation, we will report the development of a microdrop-based microfluidic platform for in vitro enzyme evolution and selection applications. A microfluidic chip has been developed and fabricated using the standard photolithography method in conjunction with electroplating and hot embossing techniques. A cross channel geometry was used to focus liquid flows for droplet generation. To realize on-chip compartmentalised bio-reactions, two droplet generators were fabricated on the same chip. Experiments have been carried out to measure droplet size, generation rate and speed using a photographic technique. Droplet size was found to be decreasing with increasing focusing oil flow rate for a given aqueous phase flow rate. When two droplet generators are used in the same chip, the droplets may be generated asynchronously due to different flow conditions. If the droplets were significantly smaller than channel size, the faster moving droplets could pass the slower moving droplets with little coalescence. If the droplets were of the channel size, the faster moving droplets would break or fuse with the slow droplets. To achieve high rate of droplet fusion, active control should be in place for synchronous generation and fusion
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Legitimacy in conflict: concepts, practices, challenges
The study of legitimacy in situations of conflict and peacebuilding has increased in recent years. However, current work on the topic adopts many assumptions, definitions, and understandings from classical legitimacy theory, which centers on the relationship between the nation-state and its citizens. In this introduction, we provide a detailed critical overview of current theories of legitimacy and legitimation and demonstrate why they have only limited applicability in conflict and post-conflict contexts, focusing on the three main areas that the articles included in this special issue examine: audiences for legitimacy, sources of legitimacy, and legitimation. In particular, we show how conflict and post-conflict contexts are marked by the fragmentation and personalization of power; the proliferation and fragmentation of legitimacy audiences; and ambiguity surrounding legitimation strategies
Transformation of SV40-immortalized human uroepithelial cells by 3-methylcholanthrene increases IFN- and Large T Antigen-induced transcripts
<p>Abstract</p> <p>Background</p> <p>Simian Virus 40 (SV40) immortalization followed by treatment of cells with 3-methylcholanthrene (3-MC) has been used to elicit tumors in athymic mice. 3-MC carcinogenesis has been thoroughly studied, however gene-level interactions between 3-MC and SV40 that could have produced the observed tumors have not been explored. The commercially-available human uroepithelial cell lines were either SV40-immortalized (HUC) or SV40-immortalized and then 3-MC-transformed (HUC-TC).</p> <p>Results</p> <p>To characterize the SV40 - 3MC interaction, we compared human gene expression in these cell lines using a human cancer array and confirmed selected changes by RT-PCR. Many viral Large T Antigen (Tag) expression-related changes occurred in HUC-TC, and it is concluded that SV40 and 3-MC may act synergistically to transform cells. Changes noted in <it>IFP 9-27, 2'-5' OAS, IF 56, MxA </it>and <it>MxAB </it>were typical of those that occur in response to viral exposure and are part of the innate immune response. Because interferon is crucial to innate immune host defenses and many gene changes were interferon-related, we explored cellular growth responses to exogenous IFN-γ and found that treatment impeded growth in tumor, but not immortalized HUC on days 4 - 7. Cellular metabolism however, was inhibited in <it>both </it>cell types. We conclude that IFN-γ <it>metabolic </it>responses were functional in both cell lines, but IFN-γ <it>anti-proliferative </it>responses functioned only in tumor cells.</p> <p>Conclusions</p> <p>Synergism of SV40 with 3-MC or other environmental carcinogens may be of concern as SV40 is now endemic in 2-5.9% of the U.S. population. In addition, SV40-immortalization is a generally-accepted method used in many research materials, but the possibility of off-target effects in studies carried out using these cells has not been considered. We hope that our work will stimulate further study of this important phenomenon.</p
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Development of guidance on applications of regulatory requirements for regulating large, contaminated equipment and large decommissioning and decontamination (D and D) components
In 1985, the International Atomic Energy Agency issued revised regulations for the safe transport of radioactive material. Significant were major changes to requirements for Low Specific Activity material and Surface Contaminated Objects. As these requirements were adopted into regulations in the US, it was recognized that guidance on how to apply these requirements to large, contaminated/activated pieces of equipment and decommissioning and decontamination objects would be needed both by the regulators and those regulated to clarify technical uncertainties and ensure implementation. Thus, the US Department of Transportation and the US Nuclear Regulatory Commission, with assistance of staff from Oak Ridge National Laboratory, are preparing regulatory guidance which will present examples of acceptable methods for demonstrating compliance with the revised rules for large items. Concepts being investigated for inclusion in the pending guidance are discussed in this paper. Under current plans, the guidance will be issued for public comment before final issuance in 1997
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Guidance and methods for satisfying low specific activity material and surface contaminated object regulatory requirements
The US Department of Transportation (DOT) and the US Nuclear Regulatory Commission (NRC) have prepared a comprehensive set of draft guidance for shippers and inspectors to use when applying the newly imposed regulatory requirements for low specific activity (LSA) material and surface contaminated objects (SCOs). These requirements represent significant departures in some areas from the manner in which these materials and objects were regulated by the earlier versions of the regulations. The proper interpretation and application of the regulatory criteria can require a fairly complex set of decisions be made. To assist those trying to apply these regulatory requirements, a detailed set of logic flow diagrams representing decisions related to multiple factors were prepared and included in the draft report for comment on Categorizing and Transporting Low Specific Activity Materials and Surface Contaminated Objects. These logic flow diagrams, as developed, are specific to the US regulations, but were readily adaptable to the IAEA regulations. The diagrams have been modified accordingly and tied directly to specific paragraphs in IAEA Safety Series No. 6. This paper provides the logic flow diagrams adapted to the IAEA regulations, and demonstrates how these diagrams can be used to assist consignors and inspectors in assessing compliance of shipments with the LSA material and SCO regulatory requirements
Terminal valuations, growth rates and the implied cost of capital
This article is published with open access at Springerlink.comWe develop a model based on the notion that prices lead earnings,
allowing for a simultaneous estimation of the implied growth rate and the cost of
equity capital for US industrial sectors. The major difference between our approach
and that in prior literature is that ours avoids the necessity to make assumptions
about terminal values and consequently about future growth rates. In fact, growth
rates are an endogenous variable, which is estimated simultaneously with the
implied cost of equity capital. Since we require only 1-year-ahead forecasts of
earnings and no assumptions about dividend payouts, our methodology allows us to
estimate ex ante aggregate growth and risk premia over a larger sample of firms than
has previously been possible. Our estimate of the risk premium being between 3.1
and 3.9 % is at the lower end of recent estimates, reflecting the inclusion of these
short-lived companies. Our estimate of the long run growth is from 4.2 to 4.7 %
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