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Search for a Correlation Between Very-High-Energy Gamma Rays and Giant Radio Pulses in the Crab Pulsar
Get PDFWe present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E γ \u3e 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On ~8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits
Veritas Observations Of Day-Scale Flaring Of M 87 In 2010 April
Get PDFVERITAS has been monitoring the very-high-energy (VHE; \u3e 100 GeV) gamma-ray activity of the radio galaxy M 87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 ± 0.16) × 10–11 cm–2 s–1 at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 ± 0.68) × 10–11 cm–2 s–1 for E \u3e 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90+0.22 –0.15 days. The shortest detected exponential rise time is three times as long, at 2.87+1.65 –0.99 days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 ± 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region
Organisational Factors Determining Export Performance and Electronic Commerce Adoption: An Empirical Investigation
Get PDFIreland’s economic performance over the past two decades was largely driven by the exporting sector of the economy. Vigorous export growth largely reflected the success of the economy in securing inward foreign direct investments flows, mainly from the United States (Central Bank and Financial Services Authority of Ireland, 2009). Given that Ireland has a population of just over 4.23 million (CSO, 2006) it is imperative that Irish organisations expand into foreign markets to gain a larger market base. It is against this background of international trade that this paper is set. This is a study of export performance and electronic commerce and it seeks to ascertain the extent to which organisational factors impact on export performance and electronic commerce adoption in the Information and Communications Technology (ICT) sector in Ireland. The core objectives of this study are: to identify the internal organisational characteristics of both export performance and electronic commerce adoption and to examine the key organisational internal determinants of export performance in the ICT sector in Ireland. The empirical findings provide evidence of a relation between organisational age, managerial education, international experience and export performance, and electronic commerce adoption
Advertising the Thin Ideal-The Effect on Women
Get PDFDebate on the thin ideal has been prevalent for many decades, however given the substantial increase in eating disorders and the omnipresent influence of the media the time is now ripe for decisive action in the area of women in advertising. Most research in this area has focused on the psychological impact of the thin ideal. The new research presented in this paper is important as it explores the marketing implications of the portrayal of women in the fashion and cosmetic industry. The success of this industry depends entirely on how receptive consumers are to the images portrayed. This paper explores the effect advertising in the form of television, magazine and billboard media has on the female consumer with regard to body dissatisfaction and eating disorders. It is conclusive from the research that respondents believe that there is an association between the advertising of the thin ideal and body dissatisfaction and eating disorders
Pump Dependence Of The Dynamics Of Quantum Dot Based Waveguide Absorbers
Get PDFThe nonlinear two stage recovery of quantum dot based reverse-biased waveguide absorbers is investigated experimentally and analytically as a function of the initial ground state occupation probability of the dot. The latter is controlled experimentally by the pump pulse power. The slow stage of the recovery is exponential and its basic timescale is independent of pump power. The fast stage of the recovery is a logistic function which we analyze in detail. The relative strength of slow to fast components is highlighted and the importance of higher order absorption processes at the highest pump level is demonstrated
Managing the Future Energy Policy for Ireland: Examining the Role of Nuclear Power
Get PDFThis study assesses the attitudes and opinions of Irish people towards the use of nuclear power, and specifically examines the concept that Ireland should use nuclear power to generate electricity in the future. Currently, Ireland has a prohibition on nuclear power, with little debate or discussion on same, and with scant amounts of information published on the subject as it relates to Ireland. Conversely, from an international perspective, there is a significant volume of literature available covering all aspects of nuclear power, generated from over 50 years of nuclear power operations. Nuclear power technology is perceived as being a relatively cheap source of electricity, with some positive environmental credentials. The evidence from this study, however, highlights that the public’s attitudes are predominantly influenced by safety concerns and issues surrounding nuclear waste management. This research study has found that Irish people do not support nuclear power at present, but may consider supporting nuclear power under certain circumstances and conditions in the future. This current investigation reveals that if nuclear power could be proven to provide lower electricity costs, lower carbon dioxide emissions and enhanced security of supply, attitudes and opinions could change towards nuclear power to the point that it could become favoured. This research has identified key findings that point to a desire that relevant information on nuclear power be made available in Ireland, and also for the instigation of a national debate on the use of this technology for electricity generation in the future
Veritas Observations Of The Nova In V407 Cygni
Get PDFWe report on very high energy (E \u3e 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 × 10–12 erg cm–2 s–1 (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova
Naturally selecting solutions: the use of genetic algorithms in bioinformatics
No full textFor decades, computer scientists have looked to nature for biologically inspired solutions to computational problems; ranging from robotic control to scheduling optimization. Paradoxically, as we move deeper into the post-genomics era, the reverse is occurring, as biologists and bioinformaticians look to computational techniques, to solve a variety of biological problems. One of the most common biologically inspired techniques are genetic algorithms (GAs), which take the Darwinian concept of natural selection as the driving force behind systems for solving real world problems, including those in the bioinformatics domain. Herein, we provide an overview of genetic algorithms and survey some of the most recent applications of this approach to bioinformatics based problems
Comparative Study: The Impact of the SW3 Armband and Physical Activity Logbook in Promoting Physical Activity Adherence
Get PDFThe purpose of this study is to compare the impact of portable body sensing technology (SW3 Armband) to a traditional approach, a Physical Activity Logbook (PAL) in promoting physical activity adherence. Participant’s physical activity adherence levels were recorded over a six month period. The primary research involved a six month physical activity programme that commenced in October 2010 and finished in April 2011. Females (n=30) were recruited through a local newspaper and a radio advertisement. Participants were randomised to an Intervention Group (n=15) or a Control Group (n=15). To be eligible to participate in the study the following criteria applied: (1) age range: 30-50 years, (2) gender: female, (3) location: live in the Letterkenny or surrounding area, (4) physical activity levels: did not meet the World Health Organisations (WHO, 2011) recommendations for physical activity, (5) have access to windows XP. Participants were assessed at Baseline, Time 1 (week eight), Time 2 (week eighteen) and Time 3 (week twenty-six) regarding the amount of physical activity minutes accumulated. The results of this study specify that the Control Group (CG) performed a greater amount of moderate intensity minutes of physical activity compared to the Intervention Group (IG). At the end of Time 3, the CG was performing three times more moderate physical activity than that of the IG. Therefore, the traditional method of a PAL has proved to be an effective method of promoting physical activity adherence when compared to that of the SW3 Armband. The SW3 Armband is a wireless technological device consisting of an armband worn on the upper right arm and a wrist watch. The SW3 Armband and wrist watch displays real time, collective and significant data such as daily step count and minutes of moderate and vigorous physical activity
Emerging dynamics of human campylobacteriosis in Southern Ireland
Get PDFInfections with Campylobacter spp. pose a significant health burden worldwide. The significance of Campylobacter jejuni/Campylobacter coli infection is well appreciated but the contribution of non-C. jejuni/C. coli spp. to human gastroenteritis is largely unknown. In this study, we employed a two-tiered molecular study on 7194 patient faecal samples received by the Microbiology Department in Cork University Hospital during 2009. The first step, using EntericBio® (Serosep), a multiplex PCR system, detected Campylobacter to the genus level. The second step, utilizing Campylobacter species-specific PCR identified to the species level. A total of 340 samples were confirmed as Campylobacter genus positive, 329 of which were identified to species level with 33 samples containing mixed Campylobacter infections. Campylobacter jejuni, present in 72.4% of samples, was the most common species detected, however, 27.4% of patient samples contained non-C. jejuni/C. coli spp.; Campylobacter fetus (2.4%), Campylobacter upsaliensis (1.2%), Campylobacter hyointestinalis (1.5%), Campylobacter lari (0.6%) and an emerging species, Campylobacter ureolyticus (24.4%). We report a prominent seasonal distribution for campylobacteriosis (Spring with C. ureolyticus (March) preceeding slightly C. jejuni/C. coli (April/May)