2,124 research outputs found
An anomaly detector with immediate feedback to hunt for planets of Earth mass and below by microlensing
(abridged) The discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy
exoplanet, impressively demonstrated the sensitivity of the microlensing
technique to extra-solar planets below 10 M_earth. A planet of 1 M_earth in the
same spot would have provided a detectable deviation with an amplitude of ~ 3 %
and a duration of ~ 12 h. An early detection of a deviation could trigger
higher-cadence sampling which would have allowed the discovery of an Earth-mass
planet in this case. Here, we describe the implementation of an automated
anomaly detector, embedded into the eSTAR system, that profits from immediate
feedback provided by the robotic telescopes that form the RoboNet-1.0 network.
It went into operation for the 2007 microlensing observing season. As part of
our discussion about an optimal strategy for planet detection, we shed some new
light on whether concentrating on highly-magnified events is promising and
planets in the 'resonant' angular separation equal to the angular Einstein
radius are revealed most easily. Given that sub-Neptune mass planets can be
considered being common around the host stars probed by microlensing
(preferentially M- and K-dwarfs), the higher number of events that can be
monitored with a network of 2m telescopes and the increased detection
efficiency for planets below 5 M_earth arising from an optimized strategy gives
a common effort of current microlensing campaigns a fair chance to detect an
Earth-mass planet (from the ground) ahead of the COROT or Kepler missions. The
detection limit of gravitational microlensing extends even below 0.1 M_earth,
but such planets are not very likely to be detected from current campaigns.
However, these will be within the reach of high-cadence monitoring with a
network of wide-field telescopes or a space-based telescope.Comment: 13 pages, 4 figures and 1 table. Accepted for publication in MNRA
Inadequate reporting of research ethics review and informed consent in cluster randomized trials : review of random sample of published trials
Peer reviewedPublisher PD
Effects of Antibiotic Physicochemical Properties on Their Release Kinetics from Biodegradable Polymer Microparticles
Purpose: This study investigated the effects of the physicochemical properties of antibiotics on the morphology, loading efficiency, size, release kinetics, and antibiotic efficacy of loaded poly(DL-lactic-co-glycolic acid) (PLGA) microparticles (MPs) at different loading percentages. Methods: Cefazolin, ciprofloxacin, clindamycin, colistin, doxycycline, and vancomycin were loaded at 10 and 20 wt% into PLGA MPs using a water-in-oil-in water double emulsion fabrication protocol. Microparticle morphology, size, loading efficiency, release kinetics, and antibiotic efficacy were assessed. Results: The results from this study demonstrate that the chemical nature of loaded antibiotics, especially charge and molecular weight, influence the incorporation into and release of antibiotics from PLGA MPs. Drugs with molecular weights less than 600 Da displayed biphasic release while those with molecular weights greater than 1,000 Da displayed triphasic release kinetics. Large molecular weight drugs also had a longer delay before release than smaller molecular weight drugs. The negatively charged antibiotic cefazolin had lower loading efficiency than positively charged antibiotics. Microparticle size appeared to be mainly controlled by fabrication parameters, and partition and solubility coefficients did not appear to have an obvious effect on loading efficiency or release. Released antibiotics maintained their efficacy against susceptible strains over the duration of release. Duration of release varied between 17 and 49 days based on the type of antibiotic loaded. Conclusions: The data from this study indicate that the chemical nature of antibiotics affects properties of antibiotic-loaded PLGA MPs and allows for general prediction of loading and release kinetics
OGLE-2005-BLG-018: Characterization of Full Physical and Orbital Parameters of a Gravitational Binary Lens
We present the analysis result of a gravitational binary-lensing event
OGLE-2005-BLG-018. The light curve of the event is characterized by 2 adjacent
strong features and a single weak feature separated from the strong features.
The light curve exhibits noticeable deviations from the best-fit model based on
standard binary parameters. To explain the deviation, we test models including
various higher-order effects of the motions of the observer, source, and lens.
From this, we find that it is necessary to account for the orbital motion of
the lens in describing the light curve. From modeling of the light curve
considering the parallax effect and Keplerian orbital motion, we are able to
measure not only the physical parameters but also a complete orbital solution
of the lens system. It is found that the event was produced by a binary lens
located in the Galactic bulge with a distance kpc from the Earth.
The individual lens components with masses and are separated with a semi-major axis of AU and
orbiting each other with a period yr. The event demonstrates
that it is possible to extract detailed information about binary lens systems
from well-resolved lensing light curves.Comment: 19 pages, 6 figure
Media Ecology and the Politics of Dissent: Representations of the Hong Kong Protests in the Guardian and China Daily.
The phenomenon of protests, currently on the rise in worldwide democracies, is made known to citizens mainly through representations in the media. This paper, responding to the need for a broader view of protest media coverage in an international context, examines the ways the 2014 Hong Kong protests were covered by the online versions of two highly influential and appealing newspapers, belonging to contrasting media systems: Guardian and China Daily. By revising a typology of
previously used frames and inventing new ones this study conducts a quantitative content analysis of news articles with the view to a) highlight similarities and differences in the media coverage of protests within the above - mentioned media systems, b) find out whether the media coverage of such events with political ramifications is affected by the geopolitical interests of the countries. Based on our analysis, this study suggests the need for revising the protest paradigm as important factors - the protests’ momentum, the media systems, the new information communication technologies and certain geopolitical interests - are involved in the dynamics surrounding media coverage of protests and as such they greatly influence the framing process. Moreover, our findings demonstrated that the media coverage of the 2014 HK protests by the two newspapers was reflective of both the media systems in which they function as well as of the distinctive national standpoints
The Biosafety Research Road Map: The Search for Evidence to Support Practices in the Laboratory—Crimean Congo Haemorrhagic Fever Virus and Lassa Virus
Introduction: Crimean Congo Hemorrhagic Fever (CCHF) virus and Lassa virus (LASV) are zoonotic agents regarded as high-consequence pathogens due to their high case fatality rates. CCHF virus is a vector-borne disease and is transmitted by tick bites. Lassa virus is spread via aerosolization of dried rat urine, ingesting infected rats, and direct contact with or consuming food and water contaminated with rat excreta.
Methods: The scientific literature for biosafety practices has been reviewed for both these two agents to assess the evidence base and biosafety-related knowledge gaps. The review focused on five main areas, including the route of inoculation/modes of transmission, infectious dose, laboratory-acquired infections, containment releases, and disinfection and decontamination strategies.
Results: There is a lack of data on the safe collection and handling procedures for tick specimens and the infectious dose from an infective tick bite for CCHF investigations. In addition, there are gaps in knowledge about gastrointestinal and contact infectious doses for Lassa virus, sample handling and transport procedures outside of infectious disease areas, and the contribution of asymptomatic carriers in viral circulation.
Conclusion: Due to the additional laboratory hazards posed by these two agents, the authors recommend developing protocols that work effectively and safely in highly specialized laboratories in non-endemic regions and a laboratory with limited resources in endemic areas
The Biosafety Research Road Map: The Search for Evidence to Support Practices in Human and Veterinary Laboratories
Introduction: Lack of evidence-based information regarding potential biological risks can result in inappropriate or excessive biosafety and biosecurity risk-reduction strategies. This can cause unnecessary damage and loss to the physical facilities, physical and psychological well-being of laboratory staff, and community trust. A technical working group from the World Organization for Animal Health (WOAH, formerly OIE), World Health Organization (WHO), and Chatham House collaborated on the Biosafety Research Roadmap (BRM) project. The goal of the BRM is the sustainable implementation of evidence-based biorisk management of laboratory activities, particularly in low-resource settings, and the identification of gaps in the current biosafety and biosecurity knowledge base.
Methods: A literature search was conducted for the basis of laboratory design and practices for four selected high-priority subgroups of pathogenic agents. Potential gaps in biosafety were focused on five main sections, including the route of inoculation/modes of transmission, infectious dose, laboratory-acquired infections, containment releases, and disinfection and decontamination strategies. Categories representing miscellaneous, respiratory, bioterrorism/zoonotic, and viral hemorrhagic fever pathogens were created within each group were selected for review.
Results: Information sheets on the pathogens were developed. Critical gaps in the evidence base for safe sustainable biorisk management were identified.
Conclusion: The gap analysis identified areas of applied biosafety research required to support the safety, and the sustainability, of global research programs. Improving the data available for biorisk management decisions for research with high-priority pathogens will contribute significantly to the improvement and development of appropriate and necessary biosafety, biocontainment and biosecurity strategies for each agent
The Biosafety Research Road Map: The Search for Evidence to Support Practices in the Laboratory—Zoonotic Avian Influenza and Mycobacterium tuberculosis
Introduction: The Biosafety Research Road Map reviewed the scientific literature on a viral respiratory pathogen, avian influenza virus, and a bacterial respiratory pathogen, Mycobacterium tuberculosis. This project aims at identifying gaps in the data required to conduct evidence-based biorisk assessments, as described in Blacksell et al. One significant gap is the need for definitive data on M. tuberculosis sample aerosolization to guide the selection of engineering controls for diagnostic procedures.
Methods: The literature search focused on five areas: routes of inoculation/modes of transmission, infectious dose, laboratory-acquired infections, containment releases, and disinfection and decontamination methods.
Results: The available data regarding biosafety knowledge gaps and existing evidence have been collated and presented in Tables 1 and 2. The guidance sources on the appropriate use of biosafety cabinets for specific procedures with M. tuberculosis require clarification. Detecting vulnerabilities in the biorisk assessment for respiratory pathogens is essential to improve and develop laboratory biosafety in local and national systems
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