58,769 research outputs found
When Write is Wrong
A trio of girls attempt to have an education in a society where it is inappropriate for females to learn. Malaya is the group\u27s leader, and is called into question (and later punished) when the town officials find evidence of their educational practices
Review of 'The politics of EU accession: ideology, party strategy and the European question in Hungary', by A. Batory
No abstract available
The density of mid-sized Kuiper belt objects from ALMA thermal observations
The densities of mid-sized Kuiper belt objects are a key constraint into
understanding the assembly of objects in the outer solar system. These objects
are critical for understanding the currently unexplained transition from the
smallest Kuiper belt objects with densities lower than that of water to the
largest objects with significant rock content. Mapping this transition is made
difficult by the uncertainties in the diameters of these objects, which maps
into an even larger uncertainty in volume and thus density. The substantial
collecting area of the Atacama Large Millimeter Array allows significantly more
precise measurements of thermal emission from outer solar system objects and
could potentially greatly improve the density measurements. Here we use new
thermal observations of four objects with satellites to explore the
improvements possible with millimeter data. We find that effects due to
effective emissivity at millimeter wavelengths make it difficult to use the
millimeter data directly to find diameters and thus volumes for these bodies.
In addition, we find that when including the effects of model uncertainty, the
true uncertainties on the sizes of outer solar system objects measured with
radiometry are likely larger than those previously published. Substantial
improvement in object sizes will likely require precise occultation
measurements.Comment: AJ, in pres
Recommended from our members
Security-Informed Safety: Supporting Stakeholders with Codes of Practice
Codes of practice provide principles and guidance on how organizations can incorporate security considerations into their safety engineering lifecycle and become more security minded
Studies of reaction geometry in oxidation and reduction of the alkaline silver electrode
Two methods of surface area estimations of sintered silver electrodes have given roughness factors of 58 and 81. One method is based on constant current oxidation, the other is based on potentiostatic oxidation. Examination of both wire and sintered silver electrodes via scanning electron microscopy at various stages of oxidation have shown that important structural features are mounds of oxide. In potentiostatic oxidations these appear to form on sites instantaneously nucleated while in constant current oxidations progressive nucleation is indicated
Thermal Control Characteristics of a Diffuse Bladed, Specular Base Louver System Status Report, Jul. - Dec. 1967
Heat transfer, and thermal control characteristics of diffuse bladed louver system for spacecraf
Studies of reaction geometry in oxidation and reduction of the alkaline silver electrode Quarterly report
Reaction kinetics in oxidation and reduction of alkaline silver electrod
Detecting adaptive evolution in phylogenetic comparative analysis using the Ornstein-Uhlenbeck model
Phylogenetic comparative analysis is an approach to inferring evolutionary
process from a combination of phylogenetic and phenotypic data. The last few
years have seen increasingly sophisticated models employed in the evaluation of
more and more detailed evolutionary hypotheses, including adaptive hypotheses
with multiple selective optima and hypotheses with rate variation within and
across lineages. The statistical performance of these sophisticated models has
received relatively little systematic attention, however. We conducted an
extensive simulation study to quantify the statistical properties of a class of
models toward the simpler end of the spectrum that model phenotypic evolution
using Ornstein-Uhlenbeck processes. We focused on identifying where, how, and
why these methods break down so that users can apply them with greater
understanding of their strengths and weaknesses. Our analysis identifies three
key determinants of performance: a discriminability ratio, a signal-to-noise
ratio, and the number of taxa sampled. Interestingly, we find that
model-selection power can be high even in regions that were previously thought
to be difficult, such as when tree size is small. On the other hand, we find
that model parameters are in many circumstances difficult to estimate
accurately, indicating a relative paucity of information in the data relative
to these parameters. Nevertheless, we note that accurate model selection is
often possible when parameters are only weakly identified. Our results have
implications for more sophisticated methods inasmuch as the latter are
generalizations of the case we study.Comment: 38 pages, in press at Systematic Biolog
- …
