6,483 research outputs found
You Owe Me
In many cultures and industries gifts are given in order to influence the recipient, often at the expense of a third party. Examples include business gifts of firms and lobbyists. In a series of experiments, we show that, even without incentive or informational effects, small gifts strongly influence the recipient’s behavior in favor of the gift giver, in particular when a third party bears the cost. Subjects are well aware that the gift is given to influence their behavior but reciprocate nevertheless. Withholding the gift triggers a strong negative response. These findings are inconsistent with the most prominent models of social preferences. We propose an extension of existing theories to capture the observed behavior by endogenizing the “reference group” to whom social preferences are applied. We also show that disclosure and size limits are not effective in reducing the effect of gifts, consistent with our model. Financial incentives ameliorate the effect of the gift but backfire when available but not provided
Confidence Sets Based on Penalized Maximum Likelihood Estimators in Gaussian Regression
Confidence intervals based on penalized maximum likelihood estimators such as
the LASSO, adaptive LASSO, and hard-thresholding are analyzed. In the
known-variance case, the finite-sample coverage properties of such intervals
are determined and it is shown that symmetric intervals are the shortest. The
length of the shortest intervals based on the hard-thresholding estimator is
larger than the length of the shortest interval based on the adaptive LASSO,
which is larger than the length of the shortest interval based on the LASSO,
which in turn is larger than the standard interval based on the maximum
likelihood estimator. In the case where the penalized estimators are tuned to
possess the `sparsity property', the intervals based on these estimators are
larger than the standard interval by an order of magnitude. Furthermore, a
simple asymptotic confidence interval construction in the `sparse' case, that
also applies to the smoothly clipped absolute deviation estimator, is
discussed. The results for the known-variance case are shown to carry over to
the unknown-variance case in an appropriate asymptotic sense.Comment: second revision: new title, some comments added, proofs moved to
appendi
Gravitating Monopole-Antimonopole Systems at Large Scalar Coupling
We discuss static axially symmetric solutions of SU(2)
Einstein-Yang-Mills-Higgs theory for large scalar coupling. These regular
asymptotically flat solutions represent monopole-antimonopole chain and vortex
ring solutions, as well as new configurations, present only for larger values
of the scalar coupling. When gravity is coupled to the Yang-Mills-Higgs system,
branches of gravitating solutions emerge from the flat-space solutions, and
extend up to critical values of the gravitational coupling constant. For small
scalar coupling only two branches of gravitating solutions exist, where the
second branch connects to a generalized Bartnik-McKinnon solution. For large
scalar coupling, however, a plethora of gravitating branches can be present and
indicate the emergence of new flat-space branches.Comment: 29 pages, 13 figure
Far Right Populism and Women: The Normalisation of Gendered Anti-Muslim Racism and Gendered Culturalism in the Netherlands
Discrimination of two mixed quantum states with maximum confidence and minimum probability of inconclusive results
We study an optimized measurement that discriminates two mixed quantum states
with maximum confidence for each conclusive result, thereby keeping the overall
probability of inconclusive results as small as possible. When the rank of the
detection operators associated with the two different conclusive outcomes does
not exceed unity we obtain a general solution. As an application, we consider
the discrimination of two mixed qubit states. Moreover, for the case of
higher-rank detection operators we give a solution for particular states. The
relation of the optimized measurement to other discrimination schemes is also
discussed.Comment: 7 pages, 1 figure, accepted for publication in Phys. Rev.
Optimum unambiguous discrimination of two mixed states and application to a class of similar states
We study the measurement for the unambiguous discrimination of two mixed
quantum states that are described by density operators and of
rank d, the supports of which jointly span a 2d-dimensional Hilbert space.
Based on two conditions for the optimum measurement operators, and on a
canonical representation for the density operators of the states, two equations
are derived that allow the explicit construction of the optimum measurement,
provided that the expression for the fidelity of the states has a specific
simple form. For this case the problem is mathematically equivalent to
distinguishing pairs of pure states, even when the density operators are not
diagonal in the canonical representation. The equations are applied to the
optimum unambiguous discrimination of two mixed states that are similar states,
given by , and that belong to the class where the
unitary operator U can be decomposed into multiple rotations in the d mutually
orthogonal two-dimensional subspaces determined by the canonical
representation.Comment: 8 pages, changes in title and presentatio
Optimum unambiguous discrimination of two mixed quantum states
We investigate generalized measurements, based on positive-operator-valued
measures, and von Neumann measurements for the unambiguous discrimination of
two mixed quantum states that occur with given prior probabilities. In
particular, we derive the conditions under which the failure probability of the
measurement can reach its absolute lower bound, proportional to the fidelity of
the states. The optimum measurement strategy yielding the fidelity bound of the
failure probability is explicitly determined for a number of cases. One example
involves two density operators of rank d that jointly span a 2d-dimensional
Hilbert space and are related in a special way. We also present an application
of the results to the problem of unambiguous quantum state comparison,
generalizing the optimum strategy for arbitrary prior probabilities of the
states.Comment: final versio
Self-interacting Dark Matter and Invisibly Decaying Higgs
Self-interacting dark matter has been suggested in order to overcome the
difficulties of the Cold Dark Matter model on galactic scales. We argue that a
scalar gauge singlet coupled to the Higgs boson, which could lead to an
invisibly decaying Higgs, is an interesting candidate for this self-interacting
dark matter particle. We also present estimates on the abundance of these
particles today as well as consequences to non-Newtonian forces.Comment: 4 pages, Revte
SUPERMAN, a regulator of floral homeotic genes in Arabidopsis
We describe a locus, SUPERMAN, mutations in which result in extra stamens developing at the expense of the central carpels in the Arabidopsis thaliana flower. The development of superman flowers, from initial primordium to mature flower, is described by scanning electron microscopy. The development of doubly and triply mutant strains, constructed with superman alleles and previously identified homeotic mutations that cause alterations in floral organ identity, is also described. Essentially additive phenotypes are observed in superman agamous and superman apetala2 double mutants. The epistatic relationships observed between either apetala3 or pistillata and superman alleles suggest that the SUPERMAN gene product could be a regulator of these floral homeotic genes. To test this, the expression patterns of AGAMOUS and APETALA3 were examined in superman flowers. In wild-type flowers, APETALA3 expression is restricted to the second and third whorls where it is required for the specification of petals and stamens. In contrast, in superman flowers, APETALA3 expression expands to include most of the cells that would normally constitute the fourth whorl. This ectopic APETALA3 expression is proposed to be one of the causes of the development of the extra stamens in superman flowers. The spatial pattern of AGAMOUS expression remains unaltered in superman flowers as compared to wild-type flowers. Taken together these data indicate that one of the functions of the wild-type SUPERMAN gene product is to negatively regulate APETALA3 in the fourth whorl of the flower. In addition, superman mutants exhibit a loss of determinacy of the floral meristem, an effect that appears to be mediated by the APETALA3 and PISTILLATA gene products
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