11,480 research outputs found
Contracts as threats: On a rationale for rewarding A while hoping for B
In this paper we explore theoretically the relationship between explicit and implicit/relational contracting distinguishing between the ex-ante decision to sign an explicit contract and the ex-post decision wheter to actually apply it. We show, among other things, that the relational efficient explicit contract tends to display overcontracting on tasks or qualitative requirements (A) that are verifiable but apparently of little use for the principal. The ex-post (non)implementation of such explicit contract can then be discretionally exchanged against the provision of non contractible tasks (B) that are highly valuable for the principal.
An empirical implication of the result, consistent with casual observation in procurement, is that penalties for infringements established by explicit contracts are seldom exercised, even though violations take place and are easy to monitor and verify
Cyclic Fluctuations, Climatic Changes and Role of Noise in Planktonic Foraminifera in the Mediterranean Sea
The study of Planktonic Foraminifera abundances permits to obtain climatic
curves on the basis of percentage ratio between tropical and temperate/polar
forms. Climatic changes were controlled by several phenomena as: (i)
Milankovitch's cycles, produced by variations of astronomical parameters such
as precession, obliquity and eccentricity; (ii) continental geodynamic
evolution and orogenic belt; (iii) variations of atmospheric and oceanic
currents; (iv) volcanic eruptions; (v) meteor impacts. But while astronomical
parameters have a quasi-regular periodicity, the other phenomena can be
considered as "noise signal" in natural systems. The interplay between cyclical
astronomical variations, the "noise signal" and the intrinsic nonlinearity of
the ecologic system produces strong glacial or interglacial period according to
the stochastic resonance phenomenon.Comment: 6 pages, 4 figure
Design of a Lambda system for population transfer in superconducting nanocircuits
The implementation of a Lambda scheme in superconducting artificial atoms
could allow detec- tion of stimulated Raman adiabatic passage (STIRAP) and
other quantum manipulations in the microwave regime. However symmetries which
on one hand protect the system against decoherence, yield selection rules which
may cancel coupling to the pump external drive. The tradeoff between efficient
coupling and decoherence due to broad-band colored Noise (BBCN), which is often
the main source of decoherence is addressed, in the class of nanodevices based
on the Cooper pair box (CPB) design. We study transfer efficiency by STIRAP,
showing that substantial efficiency is achieved for off-symmetric bias only in
the charge-phase regime. We find a number of results uniquely due to
non-Markovianity of BBCN, namely: (a) the efficiency for STIRAP depends
essentially on noise channels in the trapped subspace; (b) low-frequency
fluctuations can be analyzed and represented as fictitious correlated
fluctuations of the detunings of the external drives; (c) a simple figure of
merit for design and operating prescriptions allowing the observation of STIRAP
is proposed. The emerging physical picture also applies to other classes of
coherent nanodevices subject to BBCN.Comment: 14 pages, 11 figure
Lymphocyte Subsets and Inflammatory Cytokines of Monoclonal Gammopathy of Undetermined Significance and Multiple Myeloma
Almost all multiple myeloma (MM) cases have been demonstrated to be linked to earlier monoclonal gammopathy of undetermined significance (MGUS). Nevertheless, there are no identified characteristics in the diagnosis of MGUS that have been helpful in differentiating subjects whose cancer may progress to a malignant situation. Regarding malignancy, the role of lymphocyte subsets and cytokines at the beginning of neoplastic diseases is now incontestable. In this review, we have concentrated our attention on the equilibrium between the diverse lymphocyte subsets and the cytokine system and summarized the current state of knowledge, providing an overview of the condition of the entire system in MGUS and MM. In an age where the therapy of neoplastic monoclonal gammopathies largely relies on drugs capable of acting on the immune system (immunomodulants, immunological checkpoint inhibitors, CAR-T), detailed knowledge of the the differences existing in benign and neoplastic forms of gammopathy is the main foundation for the adequate and optimal use of new drugs
General rules for bosonic bunching in multimode interferometers
We perform a comprehensive set of experiments that characterize bosonic
bunching of up to 3 photons in interferometers of up to 16 modes. Our
experiments verify two rules that govern bosonic bunching. The first rule,
obtained recently in [1,2], predicts the average behavior of the bunching
probability and is known as the bosonic birthday paradox. The second rule is
new, and establishes a n!-factor quantum enhancement for the probability that
all n bosons bunch in a single output mode, with respect to the case of
distinguishable bosons. Besides its fundamental importance in phenomena such as
Bose-Einstein condensation, bosonic bunching can be exploited in applications
such as linear optical quantum computing and quantum-enhanced metrology.Comment: 6 pages, 4 figures, and supplementary material (4 pages, 1 figure
Casimir-Polder interatomic potential between two atoms at finite temperature and in the presence of boundary conditions
We evaluate the Casimir-Polder potential between two atoms in the presence of
an infinite perfectly conducting plate and at nonzero temperature. In order to
calculate the potential, we use a method based on equal-time spatial
correlations of the electric field, already used to evaluate the effect of
boundary conditions on interatomic potentials. This method gives also a
transparent physical picture of the role of a finite temperature and boundary
conditions on the Casimir-Polder potential. We obtain an analytical expression
of the potential both in the near and far zones, and consider several limiting
cases of interest, according to the values of the parameters involved, such as
atom-atom distance, atoms-wall distance and temperature.Comment: 11 page
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Past performance and entry in procurement: An experimental investigation
There is widespread concern that incentive mechanisms based on past performance may hinder entry in procurement markets. We report results from a laboratory experiment as- sessing this concern. Within a simple dynamic procurement game where suppliers com- pete on price and quality we study how an incentive mechanism based on past per- formance affects outcomes and entry rates. Results indicate that some past-performance based mechanisms indeed hinder entry, but when appropriately designed may significantly increase both entry and quality provision without increasing costs to the procurer
The problem of analytical calculation of barrier crossing characteristics for Levy flights
By using the backward fractional Fokker-Planck equation we investigate the
barrier crossing event in the presence of Levy noise. After shortly review
recent results obtained with different approaches on the time characteristics
of the barrier crossing, we derive a general differential equation useful to
calculate the nonlinear relaxation time. We obtain analytically the nonlinear
relaxation time for free Levy flights and a closed expression in quadrature of
the same characteristics for cubic potential.Comment: 12 pages, 2 figures, presented at 5th International Conference on
Unsolved Problems on Noise, Lyon, France, 2008, to appear in J. Stat. Mech.:
Theory and Experimen
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