519 research outputs found

    Limits on Neutrino Emission from Gamma-Ray Bursts with the 40 String IceCube Detector

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    Cosmic rays have been observed on Earth with energies in excess of 1020 eV. Because cosmic rays are charged particles and are bent by galactic magnetic fields, the origin of these particles has remained a mystery. Gamma-ray bursts are one of a few astronomical sources containing an environment capable of accelerating charged particles to the energies observed. In addition, gamma-ray bursts are the leading candidate due to the fact that the total aggregate power observed in gamma-ray bursts and ultra high energy cosmic rays are the same order of magnitude. Neutrinos can only be created by hadronic interactions, so an observation of neutrinos in coincidence with a gamma-ray burst would provide compelling evidence that hadrons are accelerated in gamma-ray burst fireballs and hence the origin of cosmic rays. Using the IceCube Neutrino Observatory in its 40 string configuration, a stacked search was performed to look for the simultaneous occurrence of muon neutrinos with 117 gamma-ray bursts. This analysis is optimized on the assumption that order TeV neutrinos are produced in pγ interactions during the prompt phase of the GRB, when gamma-rays coexist with protons that are assumed to be the source of the observed extragalactic cosmic ray flux. With half the detector complete, this is the first analysis sensitive to the flux predicted by fireball phenomenology and the assumption that GRBs are the sources of the highest energy cosmic rays. No evidence for neutrino emission was found, placing a 90% CL upper fluence of 1.1 × 10-3 erg cm-2 in the energy range of 37 TeV - 2.4 PeV or 82% of the predicted fluence

    Population Ageing and Structural Adjustment

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    The future effects of population ageing on the Australian economy have been widely canvassed in recent years, most notably in the two Intergenerational Reports produced by the Australian Treasury and in the Economic Implications of an Ageing Australia report produced by the Productivity Commission. These reports are mainly concerned with the effect of ageing on the government’s budgetary position. On the income side, they focus on how ageing affects labour supply and gross domestic product. On the expenditure side, they focus on how ageing affects various spending categories including education, health and aged care. This paper provides a complementary analysis in that it considers how the structure of the economy is likely to be affected by these influences. In particular, it analyses the effects on 6-1 skill groups, 81 occupations and I06 industries. The effects are modelled by comparing two economies: a base case in which population ageing takes place, and an alternative (coul1feJfactual) economy in which the age s1mcture of the population - insofar as it affects workforce participation rates and hours worked per week -remains unchanged. In the interests of transparency, the total effect of population ageing is decomposed into: a scale effect. a skill effect, a taste effect and a public effect. The simulations are conducted using the MONASH applied general equilibrium model of the Australian economy. They generate results for each year from 2004-05 to 2024-25, but the analysis concentrates on explaining the deviations in the levels of selected variables in the base case (ageing) simulation from their values in the counterfactual (no ageing) simulation in the final year, i.e.. 202-1-25. Results are reported separately for each of the four effects and for all four taken together (the total effect). The paper pays particular attention to the implications o_(1he analysis for economic policy

    Gift Enterprises

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    A transportation logistics model for site support scheduling

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    Visual Performance in Patients with Neovascular Age Related Macular Degeneration Undergoing Treatment With Intravitreal Ranibizumab

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    Purpose. To assess visual function and its response to serial intravitreal ranibizumab (Lucentis, Genentech) in patients with neovascular age-related macular degeneration (nv-AMD). Methods. Forty-seven eyes of 47 patients with nv-AMD, and corrected distance visual acuity (CDVA) logMAR 0.7 or better, undergoing intravitreal injections of ranibizumab, were enrolled into this prospective study. Visual function was assessed using a range of psychophysical tests, while mean foveal thickness (MFT) was determined by optical coherence tomography (OCT). Results. Groupmean (±sd)MFT reduced significantly frombaseline (233±59)) to exit (205±40)) (p = 0.001). CDVA exhibited no change between baseline and exit visits (p = 0.48 and p = 0.31 resp.). Measures of visual function that did exhibit statistically significant improvements (p \u3c 0.05 for all) included reading acuity, reading speed, mesopic and photopic contrast sensitivity (CS), mesopic and photopic glare disability (GD), and retinotopic ocular sensitivity (ROS) at all eccentricities. Conclusion. Eyes with nv-AMD undergoing intravitreal ranibizumab injections exhibit improvements in many parameters of visual function. Outcome measures other than CDVA, such as CS, GD, and ROS, should not only be considered in the design of studies investigating nv-AMD, but also in treatment and retreatment strategies for patients with the condition

    Patient and physician preferences for surgical and adjuvant treatment options for rectal cancer

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    Hypothesis Patients and their clinicians hold varying preferences for surgical and adjuvant treatment therapies for rectal cancer. Design Preferences were determined using the Prospective Measure of Preference. Setting Royal Prince Alfred and St Vincent\u27s hospitals in Sydney, Australia. Participants Patients with colorectal cancer were interviewed during their postoperative hospital stay, and physicians were asked to complete a mailed survey. Main Outcome Measures The Prospective Measure of Preference method produces 2 outcome measures of preference: willingness to trade and prospective measure of preference time trade-off. Results Patients\u27 strongest preference was to avoid a stoma: more than 60% would give up a mean of 34% of their life expectancy to avoid this surgical option. This was followed by treatment options involving chemoradiotherapy, where more than 50% would give up a mean of almost 25% of their life to avoid treatment. Surgeons held stronger preferences against all adjuvant options compared with oncologists (P ≀ .01). Conclusions Patients had strong preferences against all treatment options, and these preferences frequently differed from those of physicians. These results highlight the importance of determining patients\u27 own preferences in the clinical encounter. Furthermore, the diversity of preferences of clinical subspecialists emphasizes the need for multidisciplinary treatment planning to ensure a balanced approach to treatment decision making for patients with rectal cancer

    The spread of influenza A(H1N1)pdm09 in Victorian school children in 2009:iImplications for revised pandemic planning

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    Background Victoria was the first state in Australia to experience community transmission of influenza A(H1N1)pdm09. We undertook a descriptive epidemiological analysis of the first 1,000 notified cases to describe the epidemic associated with school children and explore implications for school closure and antiviral distribution policy in revised pandemic plans. Methods Records of the first 1,000 laboratory-confirmed cases of influenza A(H1N1)pdm09 notified to the Victorian Government Department of Health between 20 May and 5 June 2009 were extracted from the state’s notifiable infectious diseases database. Descriptive analyses were conducted on case demographics, symptoms, case treatment, prophylaxis of contacts and distribution of cases in schools. Results Two-thirds of the first 1,000 cases were school-aged (5–17 years) with cases in 203 schools, particularly along the north and western peripheries of the metropolitan area. Cases in one school accounted for nearly 8% of all cases but the school was not closed until nine days after symptom onset of the first identified case. Amongst all cases, cough (85%) was the most commonly reported symptom followed by fever (68%) although this was significantly higher in primary school children (76%). The risk of hospitalisation was 2%. The median time between illness onset and notification of laboratory confirmation was four days, with only 10% of cases notified within two days of onset and thus eligible for oseltamivir treatment. Nearly 6,000 contacts were followed up for prophylaxis. Conclusions With a generally mild clinical course and widespread transmission before its detection, limited and short-term school closures appeared to have minimal impact on influenza A(H1N1)pdm09 transmission. Antiviral treatment could rarely be delivered to cases within 48 hours of symptom onset. These scenarios and lessons learned from them need to be incorporated into revisions of pandemic plans

    Nighttime removal of NOx in the summer marine boundary layer

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    The nitrate radical, NO3, and dinitrogen pentoxide, N2O5, are two important components of nitrogen oxides that occur predominantly at night in the lower troposphere. Because a large fraction of NO2 reacts to form NO3 and N2O5 during the course of a night, their fate is an important determining factor to the overall fate of NOx (=NO and NO2). As a comprehensive test of nocturnal nitrogen oxide chemistry, concentrations of O3, NO, NO2, NO3, N2O5, HNO3 and a host of other relevant compounds, aerosol abundance and composition, and meteorological conditions were measured in the marine boundary layer from the NOAA research vessel Ronald H. Brown off the East Coast of the United States as part of the New England Air Quality Study (NEAQS) during the summer of 2002. The results confirm the prominent role of NO3 and N2O5 in converting NOx to HNO3 at night with an efficiency on par with daytime photochemical conversion. The findings demonstrate the large role of nighttime chemistry in determining the NOx budget and consequent production of ozone. INDEX TERMS: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry. Citation: Brown, S. S., et al. (2004), Nighttime removal of NOx in the summer marine boundary layer, Geophys. Res. Lett., 31, L07108, doi:10.1029/2004GL01941

    Introduction: Popular Economies in South Africa

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    African economies have long been a matter of concern to anthropologists, not least in the pages of Africa. These economies are situated, somewhat contradictorily, between global settings of financialized capitalism on the one hand and impoverished local arenas where cash-based economic transfers predominate on the other. The more such economies appear to be tied to wider global arenas and operations that place them beyond the reach of ordinary people, the more necessary it is to explore the logics and decisions that tie them inexorably to specific everyday settings

    Clinical Study Visual Performance in Patients with Neovascular Age-Related Macular Degeneration Undergoing Treatment with Intravitreal Ranibizumab

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    properly cited. Purpose. To assess visual function and its response to serial intravitreal ranibizumab (Lucentis, Genentech) in patients with neovascular age-related macular degeneration (nv-AMD). Methods. Forty-seven eyes of 47 patients with nv-AMD, and corrected distance visual acuity (CDVA) logMAR 0.7 or better, undergoing intravitreal injections of ranibizumab, were enrolled into this prospective study. Visual function was assessed using a range of psychophysical tests, while mean foveal thickness (MFT) was determined by optical coherence tomography (OCT). Results. Group mean (±sd) MFT reduced significantly from baseline (233 (±59)) to exit (205 (±40)) ( = 0.001). CDVA exhibited no change between baseline and exit visits ( = 0.48 and = 0.31, resp.). Measures of visual function that did exhibit statistically significant improvements ( < 0.05 for all) included reading acuity, reading speed, mesopic and photopic contrast sensitivity (CS), mesopic and photopic glare disability (GD), and retinotopic ocular sensitivity (ROS) at all eccentricities. Conclusion. Eyes with nv-AMD undergoing intravitreal ranibizumab injections exhibit improvements in many parameters of visual function. Outcome measures other than CDVA, such as CS, GD, and ROS, should not only be considered in the design of studies investigating nv-AMD, but also in treatment and retreatment strategies for patients with the condition
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