Survival analysis of the optical brightness of GRB host galaxies

We studied the unbiased optical brightness distribution which was calculated from the survival analysis of host galaxies and its relationship with the Swift GRB data of the host galaxies observed by the Keck telescopes. Based on the sample obtained from merging the Swift GRB table and the Keck optical data we also studied the dependence of this distribution on the data of the GRBs. Finally, we compared the HGs distribution with standard galaxies distribution which is in the DEEP2 galaxies catalog.Comment: Swift: 10 Years of Discovery. Conference paper. 2-5 December 2014. La Sapienza University, Rome, Ital

A giant ring-like structure at 0.78<z<0.86 displayed by GRBs

According to the cosmological principle, Universal large-scale structure is homogeneous and isotropic. The observable Universe, however, shows complex structures even on very large scales. The recent discoveries of structures significantly exceeding the transition scale of 370 Mpc pose a challenge to the cosmological principle. We report here the discovery of the largest regular formation in the observable Universe; a ring with a diameter of 1720 Mpc, displayed by 9 gamma ray bursts (GRBs), exceeding by a factor of five the transition scale to the homogeneous and isotropic distribution. The ring has a major diameter of $43^o$ and a minor diameter of $30^o$ at a distance of 2770 Mpc in the 0.78<z<0.86 redshift range, with a probability of $2\times 10^{-6}$ of being the result of a random fluctuation in the GRB count rate. Evidence suggests that this feature is the projection of a shell onto the plane of the sky. Voids and string-like formations are common outcomes of large-scale structure. However, these structures have maximum sizes of 150 Mpc, which are an order of magnitude smaller than the observed GRB ring diameter. Evidence in support of the shell interpretation requires that temporal information of the transient GRBs be included in the analysis. This ring-shaped feature is large enough to contradict the cosmological principle. The physical mechanism responsible for causing it is unknown.Comment: Accepted for publication in MNRAS, 13 pages, 8 figures and 4 table

Large scale numerical simulations of "ultrametric" long-range depinning

The depinning of an elastic line interacting with a quenched disorder is studied for long range interactions, applicable to crack propagation or wetting. An ultrametric distance is introduced instead of the Euclidean distance, allowing for a drastic reduction of the numerical complexity of the problem. Based on large scale simulations, two to three orders of magnitude larger than previously considered, we obtain a very precise determination of critical exponents which are shown to be indistinguishable from their Euclidean metric counterparts. Moreover the scaling functions are shown to be unchanged. The choice of an ultrametric distance thus does not affect the universality class of the depinning transition and opens the way to an analytic real space renormalization group approach.Comment: submitted to Phys. Rev.

Online drug user-led harm reduction in Hungary: a review of "Daath"

Harm reduction has been increasingly finding its way into public drug policies and healthcare practices worldwide, with successful intervention measures justifiably focussing on the highest-risk groups, such as injecting drug users. However, there are also other types of drug users in need for harm reduction, even though they pose less, low, or no public health risk. Occasionally, drug users may autonomously organise themselves into groups to provide advocacy, harm reduction, and peer-help services, sometimes online. The www.daath.hu website has been operated since 2001 by the "Hungarian Psychedelic Community", an unorganised drug user group with a special interest in hallucinogenic and related substances. As of today, the website serves about 1200 visitors daily, and the online community comprises of more than 8000 registered members. The Daath community is driven by a strong commitment to the policy of harm reduction in the form of various peer-help activities that aim to expand harm reduction without promoting drug use. Our review comprehensively summarises Daath's user-led harm reduction services and activities from the last ten years, firstly outlining the history and growth phases of Daath, along with its self-set guidelines and policies. Online services (such as a discussion board, and an Ecstasy pill database) and offline activities (such as Ecstasy pill field testing, and a documentary film about psychedelics) are described. In order to extend its harm reduction services and activities in the future, Daath has several social, commercial, and legislative challenges to face. Starting with a need to realign its focus, outlooks for the upcoming operation of Daath are pondered. Future trends in harm reduction, such as separating harm-decreasing from benefit-increasing, are also discussed. We aim to share these innovative harm reduction measures and good practices in order to be critically assessed, and if found useful adapted and applied elsewhere