57,601 research outputs found
Protein Array Fabrication with E-jet Printing
We demonstrate the feasibility of fabricate biosensors with direct protein printing without complicated processes at high resolution and area coverage. Printed single protein, streptavidin-fluorescein, binds to biotin labeled with fluorescent DNA without denaturation; therefore a fluorescence microscope can detect the printed droplets as shown in Figure 7.1(a). The standard deviation of the spot size and spacing is 7.26 % and 0.693%, respectively. The e-jet printing is capable to print large area, e.g., one inch size. Half droplets of streptavidin-Cy5 are printed in 15 minutes (Figure 7.1(b)). Four-inch size printing is also available. Moreover, we have developed the multi-syringe head [1]. The head prints multiple inks by rotation. Even complicated patterns of multiple proteins (e.g., peacock shown in Figure 7.1(c)) can be printed. Printed primary antibodies can be detected under a fluorescence microscopy by incubating with fluorescently-labeled secondary antibodies [2]. These capabilities show that the e-jet printer with the multi-syringe head has feasibility to make protein chips to detect multiple proteins at lower cost than the conventional chips
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High intensity x-ray diffraction in transmission mode employing an analog of Poisson's spot
Poisson’s spot is a diffraction phenomenon producing an intensity maximum at the center of the geometric shadow of circular opaque objects. In an analog of the Poisson spot experiment, we show that a tubular cone of x-rays incident upon a crystalline sample produces diffraction spots or foci, corresponding to Bragg maxima within a transmission shadow. We discuss the beam geometry and the intensity gain recorded at the foci in transmission mode. We describe the geometric growth and decay of the foci over a linear axis with the aid of a movie sequence synchronized with the plotting of a diffractogram. The mean signal of a small central area in each successive camera image provides the intensity data for the diffractogram
Is Choice Modelling Really Necessary? Public versus expert values for marine reserves in Western Australia
One of the motivations for choice modelling is to provide values that can be used to inform decisionmakers about the non-market costs and benefits of proposed projects or policies. However, the question must be asked as to whether decision-makers consider choice modelling to be a policy relevant tool. There may be more cost-effective and convenient means of providing comparable policy guidance than commissioning a choice modelling study. For example, advice on decision options may be sought from experts, such as scientists. However, expert advice may not accurately reflect the value judgements of the public. The aim of this study is to investigate whether public and expert preferences diverge, using the choice modelling technique. Two case studies are utilised – the Ningaloo Marine Park and the proposed Ngari Capes Marine Park in Western Australia. Evidence of both divergence and convergence between public and expert values is found in different instances, with public awareness factors playing a role in this divide. Where preference divergence appears likely, decision-makers should consider choice modelling as a useful tool to inform policy.Choice modelling, valuation, experts, public, marine parks, Research Methods/ Statistical Methods,
Some Thoughts on Terminology and Discipline in Design
In this speculative paper, I will argue that the design community should attempt to develop a “dictionary” of the language of design, along the same lines as the Oxford English Dictionary was and is developed: as a catalogue of the living use of terms. I will sketch an outline of how such a project could be started quite easily with modern technologies. I will then consider one word in particular – “discipline” – as an example of the need for such a dictionary, by examining the various senses of the word and how even just reflecting on that can illuminate issues of clear communications.
Keywords:
Terminology; Lexicography; Semantics; Dictionary; Communication; Language.</p
A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions
Several transiting super-Earths are expected to be discovered in the coming
few years. While tools to model the interior structure of transiting planets
exist, inferences about the composition are fraught with ambiguities. We
present a framework to quantify how much we can robustly infer about
super-Earth and Neptune-size exoplanet interiors from radius and mass
measurements. We introduce quaternary diagrams to illustrate the range of
possible interior compositions for planets with four layers (iron core,
silicate mantles, water layers, and H/He envelopes). We apply our model to
CoRoT-7b, GJ 436b, and HAT-P-11b. Interpretation of planets with H/He envelopes
is limited by the model uncertainty in the interior temperature, while for
CoRoT-7b observational uncertainties dominate. We further find that our planet
interior model sharpens the observational constraints on CoRoT-7b's mass and
radius, assuming the planet does not contain significant amounts of water or
gas. We show that the strength of the limits that can be placed on a
super-Earth's composition depends on the planet's density; for similar
observational uncertainties, high-density super-Mercuries allow the tightest
composition constraints. Finally, we describe how techniques from Bayesian
statistics can be used to take into account in a formal way the combined
contributions of both theoretical and observational uncertainties to
ambiguities in a planet's interior composition. On the whole, with only a mass
and radius measurement an exact interior composition cannot be inferred for an
exoplanet because the problem is highly underconstrained. Detailed quantitative
ranges of plausible compositions, however, can be found.Comment: 20 pages, 10 figures, published in Ap
Evolutionary Analysis of Gaseous Sub-Neptune-Mass Planets with MESA
Sub-Neptune-sized exoplanets represent one of the most common types of
planets in the Milky Way, yet many of their properties are unknown. Here, we
present a prescription to adapt the capabilities of the stellar evolution
toolkit Modules for Experiments in Stellar Astrophysics (MESA) to model
sub-Neptune mass planets with H/He envelopes. With the addition of routines
treating the planet core luminosity, heavy element enrichment, atmospheric
boundary condition, and mass loss due to hydrodynamic winds, the evolutionary
pathways of planets with diverse starting conditions are more accurately
constrained. Using these dynamical models, we construct mass-composition
relationships of planets from 1 to 400 and investigate how
mass-loss impacts their composition and evolution history. We demonstrate that
planet radii are typically insensitive to the evolution pathway that brought
the planet to its instantaneous mass, composition and age, with variations from
hysteresis. We find that planet envelope mass loss timescales, , vary non-monotonically with H/He envelope mass fractions (at fixed
planet mass). In our simulations of young (100~Myr) low-mass
() planets with rocky cores, is
maximized at to . The resulting convergent mass loss
evolution could potentially imprint itself on the close-in planet population as
a preferred H/He mass fraction of . Looking ahead, we anticipate
that this numerical code will see widespread applications complementing both
3-D models and observational exoplanet surveys.Comment: 18 pages, 9 figures, and 4 tables. Accepted to the Astrophysical
Journal on August 29th, 201
Central Charge and the Andrews-Bailey Construction
From the equivalence of the bosonic and fermionic representations of
finitized characters in conformal field theory, one can extract mathematical
objects known as Bailey pairs. Recently Berkovich, McCoy and Schilling have
constructed a `generalized' character formula depending on two parameters \ra
and , using the Bailey pairs of the unitary model . By taking
appropriate limits of these parameters, they were able to obtain the characters
of model , model , and the unitary model with
central charge . In this letter we computed the effective
central charge associated with this `generalized' character formula using a
saddle point method. The result is a simple expression in dilogarithms which
interpolates between the central charges of these unitary models.Comment: Latex2e, requires cite.sty package, 13 pages. Additional footnote,
citation and reference
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