1,588 research outputs found
Maximum temperature for an Ideal Gas of Kac-Moody Fermions
A lagrangian for gauge fields coupled to fermions with the Kac-Moody group as
its gauge group yields, for the pure fermions sector, an ideal gas of Kac-Moody
fermions. The canonical partition function for the case is shown to
have a maximum temperature , where is the
coupling of the super charge operator to the fermions. This result is
similar to the case of strings but unlike strings the result is obtained from a
well-defined lagrangian.Comment: Needs subeqnarray.sty; To be published in Phys. Rev. D, Dec 15, 1995.
Some typographical errors have been corrected in the revised versio
Markdowns in Seasonal Conspicuous Goods
In common parlance, luxury and markdowns are, in many respects, contradictory concepts. Markdowns decrease product exclusivity and hence consumers’ willingness to pay (i.e., snob effect) since most consumers purchasing luxury desire uniqueness. Markdowns also encourage strategic (forward-looking) consumers to wait for lower prices (i.e., strategic effect). Yet, luxury retailers frequently adopt markdowns in practice to stimulate the demand for their seasonal products (i.e., sales effect). To study the impact of these three countervailing effects on a luxury retailer’s markdown policy and rationing strategy, this paper develops a game-theoretic model with strategic and exclusivity-seeking consumers who have heterogeneous (high and low) valuations. We characterize a luxury retailer’s equilibrium markdown and rationing strategies, and find that the retailer induces a buying frenzy (i.e., selling deliberately less than the demand) to increase consumers’ willingness to pay when they are sufficiently exclusivity-seeking. We show that the retailer’s markdown policy depends on consumers’ desire for exclusivity when the proportion of consumers with high valuation is not too high or too low. Interestingly, we find that, in such cases, consumers’ higher desire for exclusivity does not motivate the retailer to increase exclusivity and to adopt uniform pricing. To the contrary, it motivates the retailer to decrease the exclusivity and to adopt markdowns. By doing so, we identify exclusivity-seeking consumer behavior as another rationale behind markdown pricing. Lastly, we find that, when selling to exclusivity-seeking consumers, the negative impact of strategic consumer behavior is lower; however, ignoring it can be more costly
Anemia in experimental protein deficiency in the rhesus monkey with special reference to iron metabolism
1. This investigation deals with a study of the anemia of protein deficiency in Rhesus monkeys. 2. Protein deficiency was induced in 17 rhesus monkeys. Seven animals, given a protein-rich diet, served as controls. The diets of both the groups were identical in all respects, except protein. All animals were tube-fed to ensure adequate caloric intake. Hematocrit, hemoglobin, erythroctye count, serum iron, serum iron binding capacity, plasma iron tolerance curves, and iron absorption using the Fe59 fecal recovery method were studied before and at intervals of the experiment in both deficient and control groups. Protein-deficient monkeys consistently developed normocytic normochromic anemia of moderate severity. A striking fall in serum iron binding capacity, total proteins and albumin with a rise in gamma globulin was observed in all deficient animals. A significant and comparable fall in serum iron was also observed. The Fe59 absorption was depressed and there was flattening of plasma iron tolerance curves. Two deficient animals, refed a high protein diet, showed reversal of all these changes. The control animals did not show any of these changes. The mechanism of anemia and decreased iron absorption observed in the protein-deficient animals and the relevance of these findings to those in Kwashiorkor are discussed
Quantising Gravity Using Physical States of a Superstring
A symmetric zero mass tensor of rank two is constructed using the superstring
modes of excitation which satisfies the physical state constraints of a
superstring. These states have one to one correspondence with quantised
operators and are shown to be the absorption and emission quanta of the
Minkowski space Lorentz tensors using the Gupta-Bleuler method of quantisation.
The principle of equivalence makes the tensor identical to the metric tensor at
any arbitrary space-time point. The propagator for the quantised field is
deduced. The gravitational interaction is switched on by going over from
ordinary derivatives to coderivatives.The Riemann-Christoffel affine
connections are calculated and the weak field Ricci tensor is
shown to vanish. The interaction part is found out and the
exact of theory of gravity is expressed in terms of the quantised
metric. The quantum mechanical self energy of the gravitational field, in
vacuum, is shown to vanish. It is suggested that quantum gravity may be
renormalisable by the use of the physical ground states of the superstring
theory.Comment: 14 page
Learning from Many: Partner Exposure and Team Familiarity in Fluid Teams
In services where teams come together for short collaborations, managers are often advised to strive for high team familiarity so as to improve coordination and consequently, performance. However, inducing high team familiarity by keeping team membership intact can limit workers’ opportunities to acquire useful knowledge and alternative practices from exposure to a broader set of partners. We introduce an empirical measure for prior partner exposure and estimate its impact (along with that of team familiarity) on operational performance using data from the London Ambulance Service. Our analysis focuses on ambulance transports involving new paramedic recruits, where exogenous changes in team membership enable identification of the performance effect. Specifically, we investigate the impact of prior partner exposure on time spent during patient pickup at the scene and patient handover at the hospital. We find that the effect varies with the process characteristics. For the patient pickup process, which is less standardized, greater partner exposure directly improves performance. For the more standardized patient handover process, this beneficial effect is triggered beyond a threshold of sufficient individual experience. In addition, we find some evidence that this beneficial performance impact of prior partner exposure is amplified during periods of high workload, particularly for the patient handover process. Finally, a counterfactual analysis based on our estimates shows that a team formation strategy emphasizing partner exposure outperforms one that emphasizes team familiarity by about 9.2% in our empirical context
Hysteresis in mesoscopic superconducting disks: the Bean-Livingston barrier
The magnetization behavior of mesoscopic superconducting disks can show
hysteretic behavior which we explain by using the Ginzburg-Landau (GL) theory
and properly taking into account the de-magnetization effects due to
geometrical form factors. In large disks the Bean-Livingston surface barrier is
responsible for the hysteresis. While in small disks a volume barrier is
responsible for this hysteresis. It is shown that although the sample
magnetization is diamagnetic (negative), the measured magnetization can be
positive at certain fields as observed experimentally, which is a consequence
of the de-magnetization effects and the experimental set up.Comment: Latex file, 4 ps file
Hot String Soup
Above the Hagedorn energy density closed fundamental strings form a long
string phase. The dynamics of weakly interacting long strings is described by a
simple Boltzmann equation which can be solved explicitly for equilibrium
distributions. The average total number of long strings grows logarithmically
with total energy in the microcanonical ensemble. This is consistent with
calculations of the free single string density of states provided the
thermodynamic limit is carefully defined. If the theory contains open strings
the long string phase is suppressed.Comment: 13 pages, no figures, uses LaTex, some errors in equations have been
corrected, NSF-ITP-94-83, UCSBTH-94-3
Metastability and paramagnetism in superconducting mesoscopic disks
A projected order parameter is used to calculate, not only local minima of
the Ginzburg-Landau energy functional, but also saddle points or energy
barriers responsible for the metastabilities observed in superconducting
mesoscopic disks (Geim et al. Nature {\bf 396}, 144 (1998)). We calculate the
local minima magnetization and find the energetic instability points between
vortex configurations with different vorticity. We also find that, for any
vorticity, the supercurrent can reverse its flow direction on decreasing the
magnetic field before one vortex can escape.Comment: Modified version as to appear in Phys. Rev. Let
Regular networks of Luttinger liquids
We consider arrays of Luttinger liquids, where each node is described by a
unitary scattering matrix. In the limit of small electron-electron interaction,
we study the evolution of these scattering matrices as the high-energy single
particle states are gradually integrated out. Interestingly, we obtain the same
renormalization group equations as those derived by Lal, Rao, and Sen, for a
system composed of a single node coupled to several semi-infinite 1D wires. The
main difference between the single node geometry and a regular lattice is that
in the latter case, the single particle spectrum is organized into periodic
energy bands, so that the renormalization procedure has to stop when the last
totally occupied band has been eliminated. We therefore predict a strongly
renormalized Luttinger liquid behavior for generic filling factors, which
should exhibit power-law suppression of the conductivity at low temperatures
E_{F}/(k_{F}a) >
1. Some fully insulating ground-states are expected only for a discrete set of
integer filling factors for the electronic system. A detailed discussion of the
scattering matrix flow and its implication for the low energy band structure is
given on the example of a square lattice.Comment: 16 pages, 7 figure
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