The Mid-Infrared Extinction Law in the Ophiuchus, Perseus, and Serpens Molecular Clouds

We compute the mid-infrared extinction law from 3.6-24 microns in three molecular clouds: Ophiuchus, Perseus, and Serpens, by combining data from the "Cores to Disks" Spitzer Legacy Science program with deep JHKs imaging. Using a new technique, we are able to calculate the line-of-sight extinction law towards each background star in our fields. With these line-of-sight measurements, we create, for the first time, maps of the chi-squared deviation of the data from two extinction law models. Because our chi-squared maps have the same spatial resolution as our extinction maps, we can directly observe the changing extinction law as a function of the total column density. In the Spitzer IRAC bands, 3.6-8 microns, we see evidence for grain growth. Below $A_{K_s} = 0.5$, our extinction law is well-fit by the Weingartner & Draine (2001) $R_V = 3.1$ diffuse interstellar medium dust model. As the extinction increases, our law gradually flattens, and for $A_{K_s} >= 1$, the data are more consistent with the Weingartner & Draine $R_V = 5.5$ model that uses larger maximum dust grain sizes. At 24 microns, our extinction law is 2-4 times higher than the values predicted by theoretical dust models, but is more consistent with the observational results of Flaherty et al. (2007). Lastly, from our chi-squared maps we identify a region in Perseus where the IRAC extinction law is anomalously high considering its column density. A steeper near-infrared extinction law than the one we have assumed may partially explain the IRAC extinction law in this region.Comment: 38 pages, 19 figures in pre-print format. Accepted for publication in ApJ. A version with full-resolution figures can be found here: http://peggysue.as.utexas.edu/SIRTF

Cybersecurity: mapping the ethical terrain

This edited collection examines the ethical trade-offs involved in cybersecurity: between security and privacy; individual rights and the good of a society; and between the types of burdens placed on particular groups in order to protect others. Foreword Governments and society are increasingly reliant on cyber systems. Yet the more reliant we are upon cyber systems, the more vulnerable we are to serious harm should these systems be attacked or used in an attack. This problem of reliance and vulnerability is driving a concern with securing cyberspace. For example, a ‘cybersecurity’ team now forms part of the US Secret Service. Its job is to respond to cyber-attacks in specific environments such as elevators in a building that hosts politically vulnerable individuals, for example, state representatives. Cybersecurity aims to protect cyberinfrastructure from cyber-attacks; the concerning aspect of the threat from cyber-attack is the potential for serious harm that damage to cyber-infrastructure presents to resources and people. These types of threats to cybersecurity might simply target information and communication systems: a distributed denial of service (DDoS) attack on a government website does not harm a website in any direct way, but prevents its normal use by stifling the ability of users to connect to the site. Alternatively, cyber-attacks might disrupt physical devices or resources, such as the Stuxnet virus, which caused the malfunction and destruction of Iranian nuclear centrifuges. Cyber-attacks might also enhance activities that are enabled through cyberspace, such as the use of online media by extremists to recruit members and promote radicalisation. Cyber-attacks are diverse: as a result, cybersecurity requires a comparable diversity of approaches. Cyber-attacks can have powerful impacts on people’s lives, and so—in liberal democratic societies at least—governments have a duty to ensure cybersecurity in order to protect the inhabitants within their own jurisdiction and, arguably, the people of other nations. But, as recent events following the revelations of Edward Snowden have demonstrated, there is a risk that the governmental pursuit of cybersecurity might overstep the mark and subvert fundamental privacy rights. Popular comment on these episodes advocates transparency of government processes, yet given that cybersecurity risks represent major challenges to national security, it is unlikely that simple transparency will suffice. Managing the risks of cybersecurity involves trade-offs: between security and privacy; individual rights and the good of a society; and types of burdens placed on particular groups in order to protect others. These trade-offs are often ethical trade-offs, involving questions of how we act, what values we should aim to promote, and what means of anticipating and responding to the risks are reasonably—and publicly—justifiable. This Occasional Paper (prepared for the National Security College) provides a brief conceptual analysis of cybersecurity, demonstrates the relevance of ethics to cybersecurity and outlines various ways in which to approach ethical decision-making when responding to cyber-attacks

Gain of Function Research and Model Organisms in Biology

So-called ‘gain-of-function’ (GOF) research is virological research that results in a virus substantially more virulent or transmissible than its wild antecedent. GOF research has been subject to ethical analysis in the past, but the methods of GOF research have to date been underexamined by philosophers in these analyses. Here, we examine the typical animal used in influenza GOF experiments, the ferret, and show how despite its longstanding use, it does not easily satisfy the desirable criteria for an animal model. We then discuss the limitations of the ferret model, and how those epistemic limitations bear on ethical and policy questions around the risks and benefits of GOF research. We conclude with a reflection on how philosophy of science can contribute to ethical and policy debates around the risks, benefits and relative priority of life sciences research

Continuous-variable quantum key distribution field-test with true local oscillator

Continuous-variable quantum key distribution (CV-QKD) using a true local (located at the receiver) oscillator (LO) has been proposed to remove any possibility of side-channel attacks associated with transmission of the LO as well as reduce the cross-pulse contamination. Here we report an implementation of true LO CV-QKD using "off-the-shelf" components and conduct QKD experiments using the fiber optical network at Oak Ridge National Laboratory. A phase reference and quantum signal are time multiplexed and then wavelength division multiplexed with the classical communications which "coexist" with each other on a single optical network fiber. This is the first demonstration of CV-QKD with a receiver-based true LO over a deployed fiber network, a crucial step for its application in real-world situations