Attosecond Precision Multi-km Laser-Microwave Network

Synchronous laser-microwave networks delivering attosecond timing precision are highly desirable in many advanced applications, such as geodesy, very-long-baseline interferometry, high-precision navigation and multi-telescope arrays. In particular, rapidly expanding photon science facilities like X-ray free-electron lasers and intense laser beamlines require system-wide attosecond-level synchronization of dozens of optical and microwave signals up to kilometer distances. Once equipped with such precision, these facilities will initiate radically new science by shedding light on molecular and atomic processes happening on the attosecond timescale, such as intramolecular charge transfer, Auger processes and their impact on X-ray imaging. Here, we present for the first time a complete synchronous laser-microwave network with attosecond precision, which is achieved through new metrological devices and careful balancing of fiber nonlinearities and fundamental noise contributions. We demonstrate timing stabilization of a 4.7-km fiber network and remote optical-optical synchronization across a 3.5-km fiber link with an overall timing jitter of 580 and 680 attoseconds RMS, respectively, for over 40 hours. Ultimately we realize a complete laser-microwave network with 950-attosecond timing jitter for 18 hours. This work can enable next-generation attosecond photon-science facilities to revolutionize many research fields from structural biology to material science and chemistry to fundamental physics.Comment: 42 pages, 13 figure

Flavor Ratios of Astrophysical Neutrinos: Implications for Precision Measurements

We discuss flavor-mixing probabilities and flavor ratios of high energy astrophysical neutrinos. In the first part of this paper, we expand the neutrino flavor-fluxes in terms of the small parameters U_{e3} and pi/4 - theta_{23}, and show that there are universal first and second order corrections. The second order term can exceed the first order term, and so should be included in any analytic study. We also investigate the probabilities and ratios after a further expansion around the tribimaximal value of sin^2 theta_{12} = 1/3. In the second part of the paper, we discuss implications of deviations of initial flavor ratios from the usually assumed, idealized flavor compositions for pion, muon-damped, and neutron beam sources, viz., (1 : 2 : 0), (0 : 1 : 0), and (1 : 0 : 0), respectively. We show that even small deviations have significant consequences for the observed flavor ratios at Earth. If initial flavor deviations are not taken into account in analyses, then false inferences for the values in the PMNS matrix elements (angles and phase) may result.Comment: 32 pages, 15 figures. Minor changes, matches version in JHE

Making justice more accessible

From the point of view of the Citizen, Justice is not always readily accessible. Either because it is a lengthy process, potentially expensive, sometimes unclear or simply scary, people will often avoid or withdraw from a judicial process, especially in those cases that involve relatively small amounts. This results in the giving up of a basic right, with the potential loss of rightful benefits. In this paper we briefly analyze the main aspects that impair access to Justice nowadays. We then move on to look at recent technological developments in the field of Online Dispute Resolution to argue that these can, in the near future, have a significant role in improving access to Justice. Specifically, we analyze the UMCourt Conflict Resolution Framework, developed by our research team, and address the different dimensions in which such tools contribute to make Justice more accessible, namely through better access to useful information, support in decision-making or more cost-effective processes.Development Fund through the COMPETE Programme (operational programme for competitiveness) and by National Funds through the FCT - Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) within projects FCOMP-01-0124-FEDER-028980 (PTDC/EEISII/1386/ 2012) and PEst-OE/EEI/UI0752/201

Cone photoreceptor preservation with laser photobiomodulation in murine and human retinal dystrophy

Letter to EditorRobert J. Casson, John P. M. Wood, Jack Ao, Jagjit S. Gilhotra, Shane R. Durkin, James Muecke, WengOnn Chan, Glyn Chidlo

The Touch of Iconoclasm

This article reflects on some depicted, intentional acts of iconoclasm undertaken by Isis in Northern Iraq, and viewed as online videos. It attempts to consider what makes these moving images compelling to audiences who share an orientation to the protection and preservation of ancient artefacts. In doing so it prompts a reflection on their circulation as part of stories that get told about cultural heritage, and particularly the simple civilizational oppositions that get set up between ‘Western’ and ‘Islamic’ culture. Centring on the significance of the sensation of touch to practices of cultural inscription, it suggests that the Northern Iraq videos animate forms of synaesthesic material engagement that are denied by the modernist technologies of museum culture

The Third EGRET Catalog of High-Energy Gamma-Ray Sources

The third catalog of high-energy gamma-ray sources detected by the EGRET telescope on the Compton Gamma Ray Observatory includes data from 1991 April 22 to 1995 October 3 (Cycles 1, 2, 3, and 4 of the mission). In addition to including more data than the second EGRET catalog and its supplement, this catalog uses completely reprocessed data (to correct a number of mostly minimal errors and problems). The 271 sources (E greater than 100 MeV) in the catalog include the single 1991 solar flare bright enough to be detected as a source, the Large Magellanic Cloud, five pulsars, one probable radio galaxy detection (Cen A), and 66 high-confidence identifications of blazars (BL Lac objects, flat-spectrum radio quasars, or unidentified flat-spectrum radio sources). In addition, 27 lower-confidence potential blazar identifications are noted. Finally, the catalog contains 170 sources not yet identified firmly with known objects, although potential identifications have been suggested for a number of those. A figure is presented that gives approximate upper limits for gamma-ray sources at any point in the sky, as well as information about sources listed in the second catalog and its supplement which do not appear in this catalog

The Duty-cycle of Gamma-ray Blazars: a New Approach, New Results

We study several properties of blazars detected in the gamma-ray energy range by comparing the EGRET sources with a sample of radio blazars which can be considered possible gamma-ray candidates. We define three classes: non-gamma-ray blazars, blazars with quasi-steady gamma-ray emission, and gamma-ray blazars with substantial activity level. By combining the information of detected and candidate AGNs, we characterise the blazar activity, including the discovery of a region of consistency between the gamma-ray flaring duty-cycle and the recurrence time between flares. We also find a possible relation between the activity index of FSRQs and their black hole mass.Comment: 6 pages, 3 figures, to appear in the proceedings of the Gamma 2004 Symposium on High Energy Gamma Ray Astronomy, Heidelberg, July 2004 (AIP Proceedings Series). More detailed results are presented in Vercellone et al., 2004, MNRAS, 353, 89

Governance and Susceptibility in Conflict Resolution: Possibilities Beyond Control

Governmentality analysis offers a nuanced critique of informal Western conflict resolution by arguing that recently emerged alternatives to adversarial court processes both govern subjects and help to constitute rather than challenge formal regulation. However, this analysis neglects possibilities for transforming governance from within conflict resolution that are suggested by Foucault's contention that there are no relations of power without resistances. To explore this lacuna, I theorise and explore the affective and interpersonal nature of governance in mediation through autoethnographic reflection upon mediation practice, and Levina's insights about the relatedness of selves. The paper argues that two qualitatively different mediator capacities - technical ability and susceptibility - operate in concert to effect liberal governance. Occasionally though, difficulties and failures in mediation practice bring these capacities into tension and reveal the limits of governance. By considering these limits in mediation with Aboriginal Australian people, I argue that the susceptibility of mediator selves contains prospects for mitigating and transforming the very operations of power occurring through conflict resolution. This suggests options for expanded critical thinking about power relations operating through informal processes, and for cultivating a susceptible sensibility to mitigate liberal governance and more ethically respond to difference through conflict resolution

Biopolitics meets Terrapolitics: Political Ontologies and Governance in Settler-Colonial Australia

Crises persist in Australian Indigenous affairs because current policy approaches do not address the intersection of Indigenous and European political worlds. This paper responds to this challenge by providing a heuristic device for delineating Settler and Indigenous Australian political ontologies and considering their interaction. It first evokes Settler and Aboriginal ontologies as respectively biopolitical (focused through life) and terrapolitical (focused through land). These ideal types help to identify important differences that inform current governance challenges. The paper discusses the entwinement of these traditions as a story of biopolitical dominance wherein Aboriginal people are governed as an “included-exclusion” within the Australian political community. Despite the overall pattern of dominance, this same entwinement offers possibilities for exchange between biopolitics and terrapolitics, and hence for breaking the recurrent crises of Indigenous affairs

Sodium Selenide Toxicity Is Mediated by O2-Dependent DNA Breaks

Hydrogen selenide is a recurrent metabolite of selenium compounds. However, few experiments studied the direct link between this toxic agent and cell death. To address this question, we first screened a systematic collection of Saccharomyces cerevisiae haploid knockout strains for sensitivity to sodium selenide, a donor for hydrogen selenide (H2Se/HSe−/Se2−). Among the genes whose deletion caused hypresensitivity, homologous recombination and DNA damage checkpoint genes were over-represented, suggesting that DNA double-strand breaks are a dominant cause of hydrogen selenide toxicity. Consistent with this hypothesis, treatment of S. cerevisiae cells with sodium selenide triggered G2/M checkpoint activation and induced in vivo chromosome fragmentation. In vitro, sodium selenide directly induced DNA phosphodiester-bond breaks via an O2-dependent reaction. The reaction was inhibited by mannitol, a hydroxyl radical quencher, but not by superoxide dismutase or catalase, strongly suggesting the involvement of hydroxyl radicals and ruling out participations of superoxide anions or hydrogen peroxide. The •OH signature could indeed be detected by electron spin resonance upon exposure of a solution of sodium selenide to O2. Finally we showed that, in vivo, toxicity strictly depended on the presence of O2. Therefore, by combining genome-wide and biochemical approaches, we demonstrated that, in yeast cells, hydrogen selenide induces toxic DNA breaks through an O2-dependent radical-based mechanism