95 research outputs found
Modified screen-printed carbon electrodes application for protein tumor markers determination
Screen-printed carbon electrodes were modified with gold nanoparticles bound with DNA-aptamers by two different methods. Aptamers can selectively bind protein tumor markers from the blood plasma. The electrodes were tested. Signals obtained via squire-wavy voltammetry from modified electrodes covered with blood plasma of the healthy donors and donors with lung cancer can be distinguished
The Transverse Peculiar Velocity of the Q2237+0305 Lens Galaxy and the Mean Mass of Its Stars
Using 11-years of OGLE V-band photometry of Q2237+0305, we measure the
transverse velocity of the lens galaxy and the mean mass of its stars. We can
do so because, for the first time, we fully include the random motions of the
stars in the lens galaxy in the analysis of the light curves. In doing so, we
are also able to correctly account for the Earth's parallax motion and the
rotation of the lens galaxy, further reducing systematic errors. We measure a
lower limit on the transverse speed of the lens galaxy, v_t > 338 km/s (68%
confidence) and find a preferred direction to the East. The mean stellar mass
estimate including a well-defined velocity prior is 0.12 <= 1.94 at
68% confidence, with a median of 0.52 Msun. We also show for the first time
that analyzing subsets of a microlensing light curve, in this case the first
and second halves of the OGLE V-band light curve, give mutually consistent
physical results.Comment: 11 pages, 9 figures, 1 table; animated magnification pattern video
can be found at http://www.astronomy.ohio-state.edu/~sdp/animation.avi;
accepted for publication in Ap
The MACHO project: Microlensing Optical Depth towards the Galactic Bulge from Difference Image Analysis
We present the microlensing optical depth towards the Galactic bulge based on
the detection of 99 events found in our Difference Image Analysis (DIA) survey.
This analysis encompasses three years of data, covering ~ 17 million stars in ~
4 deg^2, to a source star baseline magnitude limit of V = 23. The DIA technique
improves the quality of photometry in crowded fields, and allows us to detect
more microlensing events with faint source stars. We find this method increases
the number of detection events by 85% compared with the standard analysis
technique. DIA light curves of the events are presented and the microlensing
fit parameters are given. The total microlensing optical depth is estimated to
be tau_(total)= 2.43^(+0.39/-0.38) x 10^(-6) averaged over 8 fields centered at
l=2.68 and b=-3.35. For the bulge component we find
tau_(bulge)=3.23^(+0.52/-0.50) x 10^(-6) assuming a 25% stellar contribution
from disk sources. These optical depths are in good agreement with the past
determinations of the MACHO Alcock et al. (1997) and OGLE Udalski et al. (1994)
groups, and are higher than predicted by contemporary Galactic models. We show
that our observed event timescale distribution is consistent with the
distribution expected from normal mass stars, if we adopt the stellar mass
function of Scalo (1986) as our lens mass function. However, we note that as
there is still disagreement about the exact form of the stellar mass function,
there is uncertainty in this conclusion. Based on our event timescale
distribution we find no evidence for the existence of a large population of
brown dwarfs in the direction of the Galactic bulge.Comment: Updated references and corrected optical depth values. tau_tot=
[2.91(+0.47/-0.45) -> 2.43^(+0.39/-0.38)] x 10^(-6) tau_bul =
[3.88(+0.63/-0.60) -> 3.23^(+0.52/-0.50)] x 10^(-6
CMB as a possible new tool to study the dark baryons in galaxies
Baryons constitute about 4% of our universe, but most of them are missing and
we do not know where and in what form they are hidden. This constitute the
so-called missing baryon problem. A possibility is that part of these baryons
are hidden in galactic halos. We show how the 7-year data obtained by the WMAP
satellite may be used to trace the halo of the nearby giant spiral galaxy M31.
We detect a temperature asymmetry in the M31 halo along the rotation direction
up to about 120 kpc. This could be the first detection of a galactic halo in
microwaves and may open a new way to probe hidden baryons in these relatively
less studied galactic objects using high accuracy CMB measurements.Comment: 8 pages, presented at the III Italian-Pakistani Workshop on
Relativistic Astrophysics, Lecce, June 20-22, 2011; to be published in
Journal of Physics: Conference Serie
Microlensing as a probe of the Galactic structure; 20 years of microlensing optical depth studies
Microlensing is now a very popular observational astronomical technique. The
investigations accessible through this effect range from the dark matter
problem to the search for extra-solar planets. In this review, the techniques
to search for microlensing effects and to determine optical depths through the
monitoring of large samples of stars will be described. The consequences of the
published results on the knowledge of the Milky-Way structure and its dark
matter component will be discussed. The difficulties and limitations of the
ongoing programs and the perspectives of the microlensing optical depth
technique as a probe of the Galaxy structure will also be detailed.Comment: Accepted for publication in General Relativity and Gravitation.
General Relativity and Gravitation in press (2010) 0
The EROS2 search for microlensing events towards the spiral arms: the complete seven season results
The EROS-2 project has been designed to search for microlensing events
towards any dense stellar field. The densest parts of the Galactic spiral arms
have been monitored to maximize the microlensing signal expected from the stars
of the Galactic disk and bulge. 12.9 million stars have been monitored during 7
seasons towards 4 directions in the Galactic plane, away from the Galactic
center. A total of 27 microlensing event candidates have been found. Estimates
of the optical depths from the 22 best events are provided. A first order
interpretation shows that simple Galactic models with a standard disk and an
elongated bulge are in agreement with our observations. We find that the
average microlensing optical depth towards the complete EROS-cataloged stars of
the spiral arms is , a number that is
stable when the selection criteria are moderately varied. As the EROS catalog
is almost complete up to , the optical depth estimated for the
sub-sample of bright target stars with () is easier to interpret. The set of microlensing events
that we have observed is consistent with a simple Galactic model. A more
precise interpretation would require either a better knowledge of the distance
distribution of the target stars, or a simulation based on a Galactic model.
For this purpose, we define and discuss the concept of optical depth for a
given catalog or for a limiting magnitude.Comment: 22 pages submitted to Astronomy & Astrophysic
Use of the Resection Map system as guidance during hepatectomy
Industrial DesignIndustrial Design Engineerin
Organic residues in archaeology - the highs and lows of recent research
YesThe analysis of organic residues from archaeological materials has become increasingly important to our understanding of ancient diet, trade and technology. Residues from diverse contexts have been retrieved and analysed from the remains of food, medicine and cosmetics to hafting material on stone arrowheads, pitch and tar from shipwrecks, and ancient manure from soils. Research has brought many advances in our understanding of archaeological, organic residues over the past two decades. Some have enabled very specific and detailed interpretations of materials preserved in the archaeological record. However there are still areas where we know very little, like the mechanisms at work during the formation and preservation of residues, and areas where each advance produces more questions rather than answers, as in the identification of degraded fats. This chapter will discuss some of the significant achievements in the field over the past decade and the ongoing challenges for research in this area.Full text was made available in the Repository on 15th Oct 2015, at the end of the publisher's embargo period
Development and validation of automatic tools for interactive recurrence analysis in radiation therapy: optimization of treatment algorithms for locally advanced pancreatic cancer
Neuronal projections from the Haller's organ and palp sensilla to the synganglion of Amblyomma americanum§
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