29,047 research outputs found
HORIZONTAL DIFFERENTIATION WITH DIFFERENTIAL INPUT COSTS: RETAIL PRICES FOR MILK BY FAT CONTENT
Markets for horizontally differentiated products with differential costs are important and have unique features. This paper studies sellers' pricing strategy and market equilibrium in these markets under various competition scenarios in the context of retail milk markets. An empirical study is also conducted to examine the effects of cost factors on retail milk prices and to characterize competition in markets in four California cities.Marketing,
Early Mars volcanic sulfur storage in the cryosphere and formation of transient SO2-rich atmospheres during the Hesperian
In a previous paper (Chassefi\`ere et al., Icarus 223, 878-891, 2013), we
have shown that most volcanic sulfur released to early Mars atmosphere could
have been trapped in the cryosphere under the form of CO2-SO2 clathrates. Huge
amounts of sulfur, up to the equivalent of a ~1 bar atmosphere of SO2, would
have been stored in the Noachian cryosphere, then massively released to the
atmosphere during Hesperian due to rapidly decreasing CO2 pressure. It would
have resulted in the formation of the large sulfate deposits observed mainly in
Hesperian terrains, whereas no or little sulfates are found at the Noachian. In
the present paper, we first clarify some aspects of our previous work. We
discuss the possibility of a smaller cooling effect of sulfur particles, or
even of a net warming effect. We point out the fact that CO2-SO2 clathrates
formed through a progressive enrichment of a preexisting reservoir of CO2
clathrates and discuss processes potentially involved in the slow formation of
a SO2-rich upper cryosphere. We show that episodes of sudden destabilization at
the Hesperian may generate 1000 ppmv of SO2 in the atmosphere and contribute to
maintaining the surface temperature above the water freezing point.Comment: 15 pages, 1 figur
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A Palette of Deepened Emotions: Exploring Emotional Challenge in Virtual Reality Games
Recent work introduced the notion of ‘emotional challenge’promising for understanding more unique and diverse player experiences (PX). Although emotional challenge has immediately attracted HCI researchers’ attention, the concept has not been experimentally explored, especially in virtual reality (VR), one of the latest gaming environments. We conducted two experiments to investigate how emotional challenge affects PX when separately from or jointly with conventional challenge in VR and PC conditions. We found that relatively exclusive emotional challenge induced a wider range of different emotions in both conditions, while the adding of emotional challenge broadened emotional responses only in VR. In both experiments, VR significantly enhanced the measured PX of emotional responses, appreciation, immersion and presence. Our findings indicate that VR may be an ideal medium to present emotional challenge and also extend the understanding of emotional (and conventional) challenge in video games
Dimensionality of social networks using motifs and eigenvalues
We consider the dimensionality of social networks, and develop experiments
aimed at predicting that dimension. We find that a social network model with
nodes and links sampled from an -dimensional metric space with power-law
distributed influence regions best fits samples from real-world networks when
scales logarithmically with the number of nodes of the network. This
supports a logarithmic dimension hypothesis, and we provide evidence with two
different social networks, Facebook and LinkedIn. Further, we employ two
different methods for confirming the hypothesis: the first uses the
distribution of motif counts, and the second exploits the eigenvalue
distribution.Comment: 26 page
Microstructure and Fe-vacancy ordering in the KFexSe2 superconducting system
Structural investigations by means of transmission electron microscopy (TEM)
on KFexSe2 with 1.5 \leq x \leq 1.8 have revealed a rich variety of
microstructure phenomena, the KFe1.5Se2 crystal often shows a superstructure
modulation along the [310] zone-axis direction, this superstructure can be well
interpreted by the Fe-vacancy order within the a-b plane. Increase of
Fe-concentration in the KFexSe2 materials could not only result in the
appearance of superconductivity but also yield clear alternations of
microstructure. Structural inhomogeneity, the complex superstructures and
defect structures in the superconducting KFe1.8Se2 sample have been
investigated based on the high-resolution TEM.Comment: 13 pages, 4 figure
Phase transitions and iron-ordered moment form factor in LaFeAsO
Elastic neutron scattering studies of an optimized LaFeAsO single crystal
reveal that upon cooling, an onset of the tetragonal (T)-to-orthorhombic (O)
structural transition occurs at K, and it exhibits a
sharp transition at K. We argue that in the
temperature range to , T and O structures may
dynamically coexist possibly due to nematic spin correlations recently proposed
for the iron pnictides, and we attribute to the formation of
long-range O domains from the finite local precursors. The antiferromagnetic
structure emerges at K, with the iron moment
direction along the O \emph{a} axis. We extract the iron magnetic form factor
and use the tabulated of Fe, Fe and Fe to
obtain a magnetic moment size of 0.8 at 9.5 K.Comment: 7 pages, 6 figures, 3 table
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