286 research outputs found
A Self-initializing Eyebrow Tracker for Binary Switch Emulation
We designed the Eyebrow-Clicker, a camera-based human computer interface system that implements a new form of binary switch. When the user raises his or her eyebrows, the binary switch is activated and a selection command is issued. The Eyebrow-Clicker thus replaces the "click" functionality of a mouse. The system initializes itself by detecting the user's eyes and eyebrows, tracks these features at frame rate, and recovers in the event of errors. The initialization uses the natural blinking of the human eye to select suitable templates for tracking. Once execution has begun, a user therefore never has to restart the program or even touch the computer. In our experiments with human-computer interaction software, the system successfully determined 93% of the time when a user raised his eyebrows.Office of Naval Research; National Science Foundation (IIS-0093367
The Structure of Molecular Clouds: II - Column Density and Mass Distributions
The formation of stars is inextricably linked to the structure of their
parental molecular clouds. Here we take a number of nearby giant molecular
clouds (GMCs) and analyse their column density and mass distributions. This
investigation is based on four new all-sky median colour excess extinction maps
determined from 2MASS. The four maps span a range of spatial resolution of a
factor of eight. This allows us to determine cloud properties at a common
spatial scale of 0.1pc, as well as to study the scale dependence of the cloud
properties. We find that the low column density and turbulence dominated part
of the clouds can be well fit by a log-normal distribution. However, above a
universal extinction threshold of 6.0 \pm 1.5mag A_V there is excess material
compared to the log-normal distribution in all investigated clouds. This
material represents the part of the cloud that is currently involved in star
formation, and thus dominated by gravity. Its contribution to the total mass of
the clouds ranges over two orders of magnitude from 0.1 to 10%. This implies
that our clouds sample various stages in the evolution of GMCs. Furthermore, we
find that the column density and mass distributions are extremely similar
between clouds if we analyse only the high extinction material. On the other
hand, there are significant differences between the distributions if only the
low extinction, turbulence dominated regions are considered. This shows that
the turbulent properties differ between clouds depending on their environment.
However, no significant influence on the predominant mode of star formation
(clustered or isolated) could be found. Furthermore, the fraction of the cloud
actively involved in star formation is only governed by gravity, with the
column density and mass distributions not significantly altered by local
feedback processes.Comment: 31 pages, 4 tables, 99 figures, accepted for publication by MNRAS, a
version with higher resolution figures can be found at
http://astro.kent.ac.uk/extinction
Informing People about CCS: A Review of Social Research Studies
This contribution examines studies on CCS public perception which have investigated the introduction of CCS information to the public. Studies published between 2007 and 2011 are considered and analysed with regard to research methods and tools and the construction of information. The relationship within which the communication of information takes place and content characteristics of the information emerge as two key aspects to be developed both from a methodological and an operational point of view
The Structure of Molecular Clouds: III - A link between cloud structure and star formation mode
We analyse extinction maps of nearby Giant Molecular Clouds to forge a link
between driving processes of turbulence and modes of star formation. Our
investigation focuses on cloud structure in the column density range above the
self shielding threshold of 1mag Av and below the star formation threshold --
the regime in which turbulence is expected to dominate. We identify clouds with
shallow mass distributions as cluster forming. Clouds that form stars in a less
clustered or isolated mode show a steeper mass distribution. Structure
functions prove inadequate to distinguish between clouds of different star
formation mode. They may, however, suggest that the turbulence in the average
cloud is governed by solenoidal forcing. The same is found using the
Delta-variance analysis which also indicates that clouds with a clustered mode
of star formation show an enhanced component of compressive driving in the
turbulent field. Thus, while star formation occurs in each cloud, independent
of the turbulent driving mechanism, compressive forcing appears to be
associated with the formation of stellar clusters.Comment: 10 pages, 3 figures, 2 tables, accepted for publication by MNRAS, a
version with higher resolution figures can be found at
http://astro.kent.ac.uk/~df
Coxsackieviruses in Ontario, January 2005 to December 2011
SummaryBackgroundIn 2010, there was an increase in enterovirus meningitis in the province of Ontario, Canada. Concurrently, there was also an increase in coxsackievirus A9-positive specimens in Alberta, Canada. This study aimed to describe the results of an investigation into the increase in coxsackievirus (A9 serotype) in 2010 in Ontario.MethodsFor the purpose of this study, we report on specimens tested by viral culture at Public Health Ontario Laboratory as part of routine laboratory testing from January 1, 2005 to December 31, 2011.ResultsCoxsackieviruses represented more than one third of enteroviruses detected, with A9 being the serotype most commonly identified. The most common specimen source in which A9 was isolated was cerebrospinal fluid, followed by nasopharyngeal swabs and stool. Patients in whom A9 was detected were older than individuals with any other coxsackievirus serotype.ConclusionsThe increase in enterovirus meningitis in Ontario in 2010 was likely due to an increase in A9 circulation. A9 was most commonly identified among children; however A9 may cause severe illness in both children and adults. Monitoring the circulation and epidemiology of enteroviruses can inform clinicians about circulating pathogens to optimize clinical testing and antibiotic use
The COMPLETE Survey of Star-Forming Regions: Phase I Data
We present an overview of data available for the Ophiuchus and Perseus
molecular clouds from ``Phase I'' of the COMPLETE Survey of Star-Forming
Regions. This survey provides a range of data complementary to the Spitzer
Legacy Program ``From Molecular Cores to Planet Forming Disks.'' Phase I
includes: Extinction maps derived from 2MASS near-infrared data using the NICER
algorithm; extinction and temperature maps derived from IRAS 60 and 100um
emission; HI maps of atomic gas; 12CO and 13CO maps of molecular gas; and
submillimetre continuum images of emission from dust in dense cores. Not
unexpectedly, the morphology of the regions appears quite different depending
on the column-density tracer which is used, with IRAS tracing mainly warmer
dust and CO being biased by chemical, excitation and optical depth effects.
Histograms of column-density distribution are presented, showing that
extinction as derived from 2MASS/NICER gives the closest match to a log-normal
distribution as is predicted by numerical simulations. All the data presented
in this paper, and links to more detailed publications on their implications
are publically available at the COMPLETE website.Comment: Accepted by AJ. Full resolution version available from:
http://www.cfa.harvard.edu/COMPLETE/papers/complete_phase1.pd
Respiratory Infection in Institutions during Early Stages of Pandemic (H1N1) 2009, Canada
Outbreaks of respiratory infection in institutions in Ontario, Canada were studied from April 20 to June 12, 2009, during the early stages of the emergence of influenza A pandemic (H1N1) 2009. Despite widespread presence of influenza in the general population, only 2 of 83 outbreaks evaluated by molecular methods were associated with pandemic (H1N1) 2009
Recommended from our members
Lack of PD-L1 Expression by iNKT Cells Improves the Course of Influenza A Infection
There is evidence indicating that invariant Natural Killer T (iNKT) cells play an important role in defense against influenza A virus (IAV). However, the effect of inhibitory receptor, programmed death-1 (PD-1), and its ligands, programmed death ligand (PD-L) 1 and 2 on iNKT cells in protection against IAV remains to be elucidated. Here we investigated the effects of these co-stimulatory molecules on iNKT cells in the response to influenza. We discovered that compare to the wild type, PD-L1 deficient mice show reduced sensitivity to IAV infection as evident by reduced weight loss, decreased pulmonary inflammation and cellular infiltration. In contrast, PD-L2 deficient mice showed augmented weight loss, pulmonary inflammation and cellular infiltration compare to the wild type mice after influenza infection. Adoptive transfer of iNKT cells from wild type, PD-L1 or PD-L2 deficient mice into iNKT cell deficient mice recapitulated these findings. Interestingly, in our transfer system PD-L1−/−-derived iNKT cells produced high levels of interferon-gamma whereas PD-L2−/−-derived iNKT cells produced high amounts of interleukin-4 and 13 suggesting a role for these cytokines in sensitivity to influenza. We identified that PD-L1 negatively regulates the frequency of iNKT cell subsets in the lungs of IAV infected mice. Altogether, these results demonstrate that lack of PD-L1 expression by iNKT cells reduces the sensitivity to IAV and that the presence of PD-L2 is important for dampening the deleterious inflammatory responses after IAV infection. Our findings potentially have clinical implications for developing new therapies for influenza
Constraining reionization using 21 cm observations in combination with CMB and Lyman-alpha forest data
In this paper, we explore the constraints on the reionization history that
are provided by current observations of the Lyman-alpha forest and the CMB.
Rather than using a particular semi-analytic model, we take the novel approach
of parametrizing the ionizing sources with arbitrary functions, and perform
likelihood analyses to constrain possible reionization histories. We find model
independent conclusions that reionization is likely to be mostly complete by
z=8 and that the IGM was 50% ionized at z=9-10. Upcoming low-frequency
observations of the redshifted 21 cm line of neutral hydrogen are expected to
place significantly better constraints on the hydrogen neutral fraction at
6<z<12. We use our constraints on the reionization history to predict the
likely amplitude of the 21 cm power spectrum and show that observations with
the highest signal-to-noise ratio will most likely be made at frequencies
corresponding to z=9-10. This result provides an important guide to the
upcoming 21 cm observations. Finally, we assess the impact that measurement of
the neutral fraction will have on our knowledge of reionization and the early
source population. Our results show that a single measurement of the neutral
fraction mid-way through the reionization era will significantly enhance our
knowledge of the entire reionization history.Comment: 15 pages, 16 figures, submitted to MNRA
- …