The Closest Look at 1H0707-495: X-ray Reverberation Lags with 1.3 Ms of Data

Reverberation lags in AGN were first discovered in the NLS1 galaxy, 1H0707-495. We present a follow-up analysis using 1.3 Ms of data, which allows for the closest ever look at the reverberation signature of this remarkable source. We confirm previous findings of a hard lag of ~100 seconds at frequencies v ~ [0.5 - 4] e-4 Hz, and a soft lag of ~30 seconds at higher frequencies, v ~ [0.6 - 3] e-3 Hz. These two frequency domains clearly show different energy dependences in their lag spectra. We also find evidence for a signature from the broad Fe K line in the high frequency lag spectrum. We use Monte Carlo simulations to show how the lag and coherence measurements respond to the addition of Poisson noise and to dilution by other components. With our better understanding of these effects on the lag, we show that the lag-energy spectra can be modelled with a scenario in which low frequency hard lags are produced by a compact corona responding to accretion rate fluctuations propagating through an optically thick accretion disc, and the high frequency soft lags are produced by short light-travel delay associated with reflection of coronal power-law photons off the disc.Comment: 11 pages, 10 figures. Accepted for publication in MNRA

Enteroaggregative Escherichia coli.

Enteroaggregative Escherichia coli (EAEC), an increasingly recognized cause of diarrhea in children in developing countries, has been particularly associated with persistent diarrhea (more than 14 days), a major cause of illness and death. Recent outbreaks implicate EAEC as a cause of foodborne illness in industrialized countries. The pathogenesis of EAEC infection is not well understood, but a model can be proposed in which EAEC adhere to the intestinal mucosa and elaborate enterotoxins and cytotoxins, which result in secretory diarrhea and mucosal damage. EAEC's ability to stimulate the release of inflammatory mediators may also play a role in intestinal illness

Development of a methodology for studying tunnel climate in long railway tunnels and for optimizing the design process of cross-passage cooling systems

When it comes into operation in 2026, the Koralmtunnel in Austria will be the world́s seventh longest railway tunnel. The installation of the power supply, telecommunications and electro-mechanical services is currently ongoing. Parts of these systems have to be protected from temperature and humidity variations and from the high dust loads which are characteristic of the tunnel atmosphere. In particular, cooling systems are required to counteract the significant amounts of heat released by some installations. Information on a large number of parameters (e.g. tunnel air temperatures) is required in the design process. However, such information is only partly available in the design stage. Hence, a prediction of tunnel air temperatures has to be made. Additionally, since hardly any information about the tunnel climate in long railway tunnels is available and in-situ mea- surements are not possible, as thermal conditions differ significantly between the construction/equipping phase and the operation phase, a novel methodology for the prediction of the tunnel climate had to be developed. This article presents a description of a new method comprising four main investigative steps and of its application to the Koralmtunnel as a selected case study. While steps 1 and 2 provide information about the actual cooling requirement and tunnel air temperatures for a period of 50 years, steps three and four of the investigation aim at the technical and economic optimization of cooling systems

Categorification of persistent homology

We redevelop persistent homology (topological persistence) from a categorical point of view. The main objects of study are diagrams, indexed by the poset of real numbers, in some target category. The set of such diagrams has an interleaving distance, which we show generalizes the previously-studied bottleneck distance. To illustrate the utility of this approach, we greatly generalize previous stability results for persistence, extended persistence, and kernel, image and cokernel persistence. We give a natural construction of a category of interleavings of these diagrams, and show that if the target category is abelian, so is this category of interleavings.Comment: 27 pages, v3: minor changes, to appear in Discrete & Computational Geometr

The impact of climate change on household food security in the Bongo District of the Upper East Region of Ghana

The study determined the impact of climate change on household food security, investigated awareness level and identified coping strategies used to mitigate negative impact of climate change in the Bongo District with emphasis on women. It was a cross-sectional survey conducted in four purposively selected farming communities in the District in the Upper East Region of Ghana. A sample size of 246 women participated in the study. Using a structured questionnaire, data were collected on socio-demographic characteristics of the participants, awareness of climate change, food consumption patterns, coping strategies and household food security. Data on rainfall and temperature for the past 30 years period in the District were obtained from the Ghana Meteorological Service. Crop yields data over a period of 21 years in the District was also obtained from the Ministry of Food and Agriculture (MOFA). The results revealed that rainfall in the Bongo District has been decreasing at - 0.3 mm per annum and maximum temperature has been increasing at 0.005 °C. More than half (62.6%) of the participants were aware of climate change in their communities. Majority (89.4%) of the participants reduced the quality and quantity of diets as coping strategy method during food shortage periods and almost all (97.2%) of the households were food insecure. Participants who reported to have observed decrease in rainfall were more likely to be food insecure (OR = 3.96; CI = 0.56 – 27.81). Participants were aware of climate change and employed reduction in the quality and quantity of diet as coping mechanism. Almost all households were food insecure. There is the need to intensify climate resistant agriculture technology such as irrigation methods to offset the negative impact of climate change on food security in the District.

Magnon dispersion and thermodynamics in CsNiF_3

We present an accurate transfer matrix renormalization group calculation of the thermodynamics in a quantum spin-1 planar ferromagnetic chain. We also calculate the field dependence of the magnon gap and confirm the accuracy of the magnon dispersion derived earlier through an 1/n expansion. We are thus able to examine the validity of a number of previous calculations and further analyze a wide range of experiments on CsNiF_3 concerning the magnon dispersion, magnetization, susceptibility, and specific heat. Although it is not possible to account for all data with a single set of parameters, the overall qualitative agreement is good and the remaining discrepancies may reflect departure from ideal quasi-one-dimensional model behavior. Finally, we present some indirect evidence to the effect that the popular interpretation of the excess specific heat in terms of sine-Gordon solitons may not be appropriate.Comment: 9 pages 10 figure

"Exhaustion" Physics in the Periodic Anderson Model using Iterated Perturbation Theory

We discuss the "exhaustion" problem in the context of the Periodic Anderson Model using Iterated Perturbation Theory(IPT) within the Dynamical Mean Field Theory. We find that, despite its limitations, IPT captures the exhaustion physics, which manifests itself as a dramatic, strongly energy dependent suppression of the effective Anderson impurity problem. As a consequence, low energy scales in the lattice case are strongly suppressed compared to the "Kondo scale" in the single-impurity picture. The IPT results are in qualitative agreement with recent Quantum Monte Carlo results for the same problem.Comment: 13 preprint pages including 1 table and 4 eps figures, replaced by revised version, accepted for publication in Europhysics Letters, added references and conten

Employing linked data and dialogue for modelling cultural awareness of a user

YesIntercultural competence is an essential 21st Century skill. A key issue for developers of cross-cultural training simulators is the need to provide relevant learning experience adapted to the learner’s abilities. This paper presents a dialogic approach for a quick assessment of the depth of a learner's current intercultural awareness as part of the EU ImREAL project. To support the dialogue, Linked Data is seen as a rich knowledge base for a diverse range of resources on cultural aspects. This paper investigates how semantic technologies could be used to: (a) extract a pool of concrete culturally-relevant facts from DBpedia that can be linked to various cultural groups and to the learner, (b) model a learner's knowledge on a selected set of cultural themes and (c) provide a novel, adaptive and user-friendly, user modelling dialogue for cultural awareness. The usability and usefulness of the approach is evaluated by CrowdFlower and Expert Inspection