IP Pegasi in outburst: Echelle spectroscopy & Modulation Doppler Tomography

We analyse a unique set of time-resolved echelle spectra of the dwarf nova IP Peg, obtained at ESO's NTT with EMMI. The dataset covers the wavelength range of 4000-7500A and shows Balmer, HeI, HeII and heavier elements in emission. IP Peg was observed one day after the peak of an outburst. The trailed spectra, spectrograms and Doppler maps show characteristics typical of IP Pegasi during the early stages of its outburst. The high-ionisation line of HeII 4686A is the most centrally located line and has the greatest radial extension compared to the HeI lines. The Balmer lines extend from close to the white dwarf up to approximately 0.45 times R_L, with the outer radius gradually increasing when moving from H delta to H alpha. The application, for the first time, of the modulation Doppler tomography technique, maps any harmonically varying components present in the system configuration. We find, as expected, that part of the strong secondary star emission in Balmer and HeI lines is modulated predominantly with the cosine term, consistent with the emission originating from the irradiated front side of the mass-donor star, facing the accreting white dwarf. For the Balmer lines the level of the modulation, compared to the average emission, decreases when moving to higher series. Emission from the extended accretion disk appears to be only weakly modulated, with amplitudes of at most a few percent of the non-varying disk emission. We find no evidence of modulated emission in the spiral arms, which if present, is relatively weak at that our signal-to-noise ratio was good enough to put a lower detection limit of any modulated emission at 5--6%. Only in one arm of the HeII 4686A line, is there a possibility of modulated emission, but again, we cannot be sure this is not caused by blending with the nearby Bowen complex of lines.Comment: 20 pages, 8 figures, submitted to Journal of Astronomical Dat

FHSD: An improved IP spoof detection method for web DDoS attacks

Distributed denial of service (DDoS) attacks represent a significant threat for companies, affecting them on a regular basis, as reported in the 2013 Information Security Breaches Survey (Technical Report. http://www.pwc.co.uk/assets/pdf/cyber-security-2013-technical-report.pdf.). The most common target is web services, the downtime of which could lead to significant monetary costs and loss of reputation. IP spoofing is often used in DDoS attacks not only to protect the identity of offending bots but also to overcome IP-based filtering controls. This paper aims to propose a new multi-layer IP Spoofing detection mechanism, called fuzzy hybrid spoofing detector (FHSD), which is based on source MAC address, hop count, GeoIP, OS passive fingerprinting and web browser user agent. The hop count algorithm has been optimized to limit the need for continuous traceroute requests, by querying the subnet IP Address and GeoIP information instead of individual IP addresses. FHSD uses fuzzy empirical rules and fuzzy largest of maximum operator to identify offensive IPs and mitigate offending traffic. The proposed system was developed and tested against the BoNeSi DDoS emulator with encouraging results in terms of detection and performance. Specifically, FHSD analysed 10 000 packets, and correctly identified 99.99% of spoofed traffic in <5 s. It also reduced the need for traceroute requests by 97%

Photometric study of selected cataclysmic variables II. Time-series photometry of nine systems

We present time-series photometry of nine cataclysmic variables: EI UMa, V844Her, V751 Cyg, V516 Cyg, GZ Cnc, TY Psc, V1315 Aql, ASAS J002511+1217.12, V1315 Aql and LN UMa. The observations were conducted at various observatories, covering 170 hours and comprising 7,850 data points in total. For the majority of targets we confirm previously reported periodicities and for some of them we give, for the first time, their spectroscopic orbital periods. For those dwarf-nova systems which we observed during both quiescence and outburst, the increase in brightness was followed by a decrease in the amount of flickering. Quasi-periodic oscillations have either been discovered, or were confirmed. For the eclipsing system V1315 Aql we have covered 9 eclipses, and obtained a refined orbital ephemeris. We find that, during its long baseline of observations, no change in the orbital period of this system has occurred. V1315 Aql also shows eclipses of variable depth.Comment: 30 pages, 16 figures, 4 tables. Submitted to JA

Evaluating the Usability Impacts of Security Interface Adjustments in Word 2007

Prior research has suggested that integrating security features with user goals and increasing their visibility would improve the usability of the associated functionalities. This paper investigates how these approaches affect the efficiency of use and the level of user satisfaction. The user interface of Word 2007 was modified according to these principles, with usability tests being conducted with both the original and the modified user interfaces. The results suggest that integrating security features with user goals improves the efficiency of use, but the impacts upon user satisfaction cannot be clearly identified based on the collected data. No indications of any major improvements in the efficiency of use or user satisfaction are found when the visibility of security features is increased. The combination of these two methods seems to improve both the efficiency of use and the resulting user satisfaction

Assessing end-user awareness of social engineering and phishing

Social engineering is a significant problem involving technical and nontechnical ploys in order to acquire information from unsuspecting users. This paper presents an assessment of user awareness of such methods in the form of email phishing attacks. Our experiment used a webbased survey, which presented a mix of 20 legitimate and illegitimate emails, and asked participants to classify them and explain the rationale for their decisions. This assessment shows that the 179 participants were 36% successful in identifying legitimate emails, versus 45% successful in spotting illegitimate ones. Additionally, in many cases, the participants who identified illegitimate emails correctly could not provide convincing reasons for their selections

Uncoupling of myofilament Ca2+-sensitivity from troponin I phosphorylation by mutations can be reversed by Epigallocatechin-3-Gallate.

AIMS: Heart muscle contraction is regulated via the β-adrenergic response that leads to phosphorylation of Troponin I (TnI) at Ser22/23, which changes the Ca(2+)-sensitivity of the cardiac myofilament. Mutations in thin filament proteins that cause Dilated Cardiomyopathy (DCM) and some mutations that cause Hypertrophic Cardiomyopathy (HCM) abolish the relationship between TnI phosphorylation and Ca(2+)-sensitivity (uncoupling). Small molecule Ca(2+)-sensitisers and Ca(2+)-desensitisers that act upon troponin alter the Ca(2+)-sensitivity of the thin filament but their relationship with TnI phosphorylation has never been studied before. METHODS AND RESULTS: Quantitative in vitro motility assay showed that 30 μM EMD57033 and 100 μM Bepridil increase Ca(2+)-sensitivity of phosphorylated cardiac thin filaments by 3.1 and 2.8-fold respectively. Additionally they uncoupled Ca(2+)-sensitivity from TnI phosphorylation, mimicking the effect of HCM mutations. EGCG decreased Ca(2+)-sensitivity of phosphorylated and unphosphorylated wild-type thin filaments equally (by 2.15±0.45 and 2.80±0.48-fold respectively), retaining the coupling. Moreover, EGCG also reduced Ca(2+)-sensitivity of phosphorylated but not unphosphorylated thin filaments containing DCM and HCM-causing mutations, thus the dependence of Ca(2+)-sensitivity upon TnI phosphorylation of uncoupled mutant thin filaments was restored in every case. In single mouse heart myofibrils, EGCG reduced Ca(2+)-sensitivity of force and k(ACT) and also preserved coupling. Myofibrils from the ACTC E361G (DCM) mouse were uncoupled; EGCG reduced Ca(2+)-sensitivity more for phosphorylated than unphosphorylated myofibrils, thus restoring coupling. CONCLUSION: We conclude that it is possible to both mimic and reverse the pathological defects in troponin caused by cardiomyopathy mutations pharmacologically. Re-coupling by EGCG may be of potential therapeutic significance for treating cardiomyopathies

Damage to the right insula disrupts the perception of affective touch

© 2020 Kirsch et al. This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use and redistribution provided that the original author and source are credited.Specific, peripheral C-tactile afferents contribute to the perception of tactile pleasure, but the brain areas involved in their processing remain debated. We report the first human lesion study on the perception of C-tactile touch in right hemisphere stroke patients (N = 59), revealing that right posterior and anterior insula lesions reduce tactile, contralateral and ipsilateral pleasantness sensitivity, respectively. These findings corroborate previous imaging studies regarding the role of the posterior insula in the perception of affective touch. However, our findings about the crucial role of the anterior insula for ipsilateral affective touch perception open new avenues of enquiry regarding the cortical organization of this tactile system.Peer reviewe