13,109 research outputs found
Global mapping of iron and titanium oxides in the lunar megaregolith and subsurface
[Abstract]:
This paper reports mapping results obtained by remote sensing analysis of Iron and Titanium oxides in the megaregolith under the lunar Highlands regolith and in the subsurface under the Mare and South Pole Aitken basin regolith. FeO and TiO2 images were mosaicked from data extracted from the 1994 Clementine lunar orbiter mission from 600 N to 600 S, using the Lucey et al. technique (2000). These images then used to study the ejecta blanket for each of 2059 craters analysed using ISIS software (US Geological Survey). Average weight percentage values for each crater ejecta blanket were interpolated to derive underlying global Province Maps for FeO and TiO2. The Moon was divided into five (5) provinces as a balance of the needs of analysis requirements and simplicity. Division of global TiO2 weight percentages in the megaregolith /subsurface five provinces was matching the observed distribution of that at the surface. In contrast, division of lunar FeO into 5 Provinces reveals unexpectedly elevated iron concentrations (3.8 to 6.4%) in some areas of the Highland megaregolith. This Province of elevated iron oxide is termed “Highland II”
Defining Markets That Involve Multi-Sided Platform Businesses: An Empirical Framework With an Application to Google's Purchase of DoubleClick
A multi-sided platform (MSP) serves as an intermediary for two or more groups of customers who are linked by indirect network effects. Recent research has found that MSPs are significant in many industries and that some standard economic results, such as the Lerner Index, do not apply to them, in material ways, without some significant modification to take linkages between the multiple sides into account. This article extends several key tools used for the analysis of mergers to situations in which one or more of the suppliers are MSPs. It shows that the application of traditional tools to mergers involving MSPs results in biases the direction of which depends on the particular tool being used and other conditions. It also extends these tools to the analysis of the merger of MSPs. The techniques are illustrated with an application to an acquisition by Google in the online advertising industry.
Cognitive Contact Linguistics as an essential ingredient of diachronic construction grammar
BACKGROUND: “Diachronic construction grammar” is a field of investigation that brings together two, still relatively young, research traditions, which one could characterize as historical construction grammar and constructionist grammaticalization theory (Noël 2013). Both traditions deal with the (phylogenetic) development of “constructicons”, i.e. with evolutions in the constructional resources of languages, but they have come to this research focus from different angles, the latter being the result of a constructionist turn in grammaticalization theoretical thinking, while the former has launched off from synchronic constructionist linguistics, comprising work on schematization, “diachronic constructional semasiology” (Colleman & De Clerck 2011), “constructional attrition” (Colleman & Noël 2012) as well …postprin
The modal BE BOUND TO constructions and the dynamic English constructicon
Session: WS Diachronic Construction GrammarOne possible characterization of the essence of a diachronic construction grammar approach to language change is that it tries to account for the emergence of individual constructions in the constructicon of a language, as well their disappearance from it, with reference to relevant other parts of the constructicon. For instance, rather than considering the emergence of grammatical constructions as individual linear changes happening to certain lexical material in particular morphosyntactic contexts, diachronic construction grammar works with snapshots of the constructicon of a language taken at different intervals and explains the appearance of new constructions against the backdrop of …postprin
Patterns and meanings: Using corpora for English language research and teaching. By ALAN PARTINGTON. (Studies in corpus linguistics 2.) Amsterdam & Philadelphia: John Benjamins, 1998
A radically usage-based account of the development of the English 'epistemic' be bound to construction
Oral PresentationPresent-day English has two modal be bound to constructions, the most common one an “epistemic” one and a less frequent deontic one. It is a matter of debate whether the more frequent construction is epistemic or a case of “participant-external necessity”, but diachronic corpus data show that it appeared much later than the deontic construction. The semasiological evolution of the form be bound to consequently resembles the “path” Bybee et al. (1994) suggest for should. However, though such semasiological paths are valid explananda for historical linguistics, they should not be taken to ...postprin
Solubility behaviour, crystallisation kinetics and pour point : a comparison of linear alkane and triacyl glyceride solute/solvent mixtures
Mixtures of either a hydrocarbon wax in a hydrocarbon solvent or a long chain triacyl glyceride (TAG) in a TAG solvent show complex solubility boundary temperature hysteresis and precipitated crystal network formation leading to gelation. For these industrially-important systems, we show how the equilibrium solubility and its hysteresis, crystallisation kinetics and pour point temperature vary with solute concentration for representative examples of both hydrocarbon (n-tetracosane (C24) solute in n-heptane (C7) solvent) and TAG (tristearin (SSS) solute in tricaprylin (CCC) solvent) mixtures. The behaviour is modelled with good accuracy; thereby providing a useful aid to formulation and process optimisation
Old Main-Sequence Turnoff Photometry in the Small Magellanic Cloud. I. Constraints on the Star Formation History in Different Fields
We present ground-based B and R-band color-magnitude diagrams (CMDs),
reaching the oldest main-sequence turnoffs with good photometric accuracy for
twelve fields in the Small Magellanic Cloud (SMC). Our fields, located between
~1 and ~4 degrees from the center of the galaxy, are situated in different
parts of the SMC such as the "Wing'' area, and towards the West and South. In
this paper we perform a first analysis of the stellar content in our SMC fields
through comparison with theoretical isochrones and color functions (CFs). We
find that the underlying spheroidally distributed population is composed of
both intermediate-age and old stars and that its age composition does not show
strong galacto-centric gradients. The three fields situated toward the east, in
the Wing region, show very active current star formation. However, only in the
eastern field closest to the center do we find an enhancement of recent star
formation with respect to a constant SFR(t). The fields corresponding to the
western side of the SMC present a much less populated young MS, and the CF
analysis indicates that the SFR(t) greatly diminished around 2 Gyr ago in these
parts. Field smc0057, the closest to the center of the galaxy and located in
the southern part, shows recent star formation, while the rest of the southern
fields present few bright MS stars. The structure of the red clump in all the
CMDs is consistent with the large amount of intermediate-age stars inferred
from the CMDs and color functions. None of the SMC fields presented here are
dominated by old stellar populations, a fact that is in agreement with the lack
of a conspicuous horizontal branch in all these SMC CMDs. This could indicate
that a disk population is ruling over a possible old halo in all the observed
fields.Comment: To appear in A
Infrasonic observations of large-scale HE events
The Los Alamos Infrasound Program has been operating since about mid-1982, making routine measurements of low frequency atmospheric acoustic propagation. Generally, the authors work between 0.1 Hz to 10 Hz; however, much of the work is concerned with the narrower range of 0.5 to 5.0 Hz. Two permanent stations, St. George, UT, and Los Alamos, NM, have been operational since 1983, collecting data 24 hours a day. For the purposes of this discussion, the authors concentrate on their measurements of large, high explosive (HE) events at ranges of 250 km to 5330 km. Because their equipment is well suited for mobile deployments, they can easily establish temporary observing sites for special events. The measurements are from the permanent sites, as well as from various temporary sites. A few observations that are typical of the full data set are given
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