9,575 research outputs found
The Probabilistic Representative Values
In this paper we define a new family of solutions for the class of cooperative games with transferable utility, in which the set of players exhibits a structure of a priori unions.This family is deeply connected with the Shapley value for games with transferable utility but, moreover, we assume a solidarity strong connection among all the components of each union.As a consequence of this, they are disposed to delegate one coalition of members of the union to negotiate with the other unions, and, therefore, each union will have a representative coalition.Furthermore, three interesting solutions that belong to this family of values are studied, as well as the non cooperative selection of the best representative coalition for each union.TU-games with unions;Shapley value;representative coalition
The Two-stage Constrained Equal Awards and Losses Rules for Multi-Issue Allocation Situation
This paper considers two-stage solutions for multi-issue allocation situations.Characterisations are provided for the two-stage constrained equal awards and constrained equal losses rules, based on the properties of composition and path independence.multi-issue allocation situations;constrained equal awards;constrained equal losses;two-stage solutions
The effect of wave conditions and surfer ability on performance and the physiological response of recreational surfers.
This study investigated the effects of wave conditions on performance and the physiological responses of surfers. After institutional ethical approval 39 recreational surfers participated in 60 surfing sessions where performance and physiological response were measured using global positioning system (GPS) heart rate monitors. Using GPS, the percentage time spent in surfing activity categories was on average 41.6, 47.0, 8.1, and 3.1% for waiting, paddling, riding, and miscellaneous activities, respectively. Ability level of the surfers, wave size, and wave period are significantly associated with the physiological, ride, and performance parameters during surfing. As the ability level of the surfers increases there is a reduction in the relative exercise intensity (e.g., average heart rate as a percentage of laboratory maximum, rpartial = -0.412, p < 0.01) which is in contrast to increases in performance parameters (e.g., maximum ride speed (0.454, p < 0.01). As the wave size increased there were reductions in physiological demand (e.g., total energy expenditure rpartial = -0.351, p ≤ 0.05) but increases in ride speed and distance measures (e.g., the maximum ride speed, 0.454, p < 0.01). As the wave period increased there were increases in intensity (e.g., average heart rate as a percentage of laboratory maximum, rp = 0.490, p < 0.01) and increases in ride speed and distance measures (e.g., the maximum ride speed, rpartial = 0.371, p < 0.01). This original study is the first to show that wave parameters and surfer ability are significantly associated with the physiological response and performance characteristics of surfing
Faint, moving objects in the Hubble Deep Field: components of the dark halo?
The deepest optical image of the sky, the Hubble Deep Field (HDF), obtained
with the Hubble Space Telescope (HST) in December 1995, has been compared to a
similar image taken in December 1997. Two very faint, blue, isolated and
unresolved objects are found to display a substantial apparent proper motion,
23+/-5 mas/yr and 26+/-5 mas/yr; a further three objects at the detection limit
of the second epoch observations may also be moving. Galactic structure models
predict a general absence of stars in the color-magnitude range in which these
objects are found. However, these observations are consistent with
recently-developed models of old white dwarfs with hydrogen atmospheres, whose
color, contrary to previous expectations, has been shown to be blue. If these
apparently moving objects are indeed old white dwarfs with hydrogen atmospheres
and masses near 0.5 M_Sun, they have ages of approximately 12 Gyr, and a local
mass density that is sufficient, within the large uncertainties arising from
the small size of the sample, to account for the entire missing Galactic
dynamical mass.Comment: 6 pages, using emulateapj, including 2 colour figures, accepted for
publication in ApJ Letter
Coupling Between Thermal Oscillations in the Surface of a Micro-Cylinder and Vortex Shedding
his article studies the coupling between prescribed thermal oscillations in the surface of a micro-cylinder and vortex shedding. We deal with the unsteady, laminar, compressible flow regime where the aerodynamics forces have a periodic behavior. It is shown that appropriate spatial and time-dependent temperature oscillations on the surface of the micro-cylinder create a resonance that controls the amplitude and frequency of both lift and drag coefficients. In practice, what we study is a mechanism to modulate the amplitude and frequency of mechanical loads of aerodynamics origin in a micro-structure by using surface temperature fluctuations as the control parameter
Metallicity inhomogeneities in local star-forming galaxies as sign of recent metal-poor gas accretion
We measure the oxygen metallicity of the ionized gas along the major axis of
seven dwarf star-forming galaxies. Two of them, SDSSJ1647+21 and SDSSJ2238+14,
show 0.5 dex metallicity decrements in inner regions with enhanced
star-formation activity. This behavior is similar to the metallicity drop
observed in a number of local tadpole galaxies by Sanchez Almeida et al. (2013)
and interpreted as showing early stages of assembling in disk galaxies, with
the star formation sustained by external metal-poor gas accretion. The
agreement with tadpoles has several implications: (1) it proves that galaxies
other than the local tadpoles present the same unusual metallicity pattern. (2)
Our metallicity inhomogeneities were inferred using the direct method, thus
discarding systematic errors usually attributed to other methods. (3) Taken
together with the tadpole data, our findings suggest a threshold around one
tenth the solar value for the metallicity drops to show up. Although galaxies
with clear metallicity drops are rare, the physical mechanism responsible for
them may sustain a significant part of the star-formation activity in the local
Universe. We argue that the star-formation dependence of the mass-metallicity
relationship, as well as other general properties followed by most local disk
galaxies, are naturally interpreted as side effects of pristine gas infall.
Alternatives to the metal poor gas accretion are examined too.Comment: Accepted for publication in ApJ. 10 pages. 5 Fig
Using Back-Scattered Laser Beams to Detect CP Violation in the Neutral Higgs Sector
We demonstrate that the ability to polarize the photons produced by
back-scattering laser beams at a TeV scale linear \epem collider could make
it possible to determine whether or not a neutral Higgs boson produced in
photon-photon collisions is a CP eigenstate. The relative utility of different
types of polarization is discussed. Asymmetries that are only non-zero if the
Higgs boson is a CP mixture are defined, and their magnitudes illustrated for a
two-doublet Higgs model with CP-violating neutral sector.Comment: 15 pages, UCD-92-18, 4 figures, postscript figure files available by
request, uses phyzzx.te
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