When individuals choose from whatever alternatives available to them the one that maximizes their utility then it is always desirable that the government provide them with as many alternatives as possible. Individuals, however, do not always choose what is best for them and their mistakes may be exacerbated by the availability of options. We analyze self-selection models, when individuals know more about themselves than it is possible for governments to know, and show that it may be socially optimal to limit and sometimes to eliminate individual choice. As an example, we apply Luce’s (1959) model of random choice to a work-retirement decision model and show that the optimal provision of choice is positively related to the degree of heterogeneity in the population and that even with very small degrees of non-rationality it may be optimal not to provide individuals any choice.
When individuals choose from whatever alternatives available to them the one that maximizes their utility then it is always desirable that the government provide them with as many alternatives as possible. Individuals, however, do not always choose what is best for them and their mistakes may be exacerbated by the availability of options. We analyze self-selection models, when individuals know more about themselves than it is possible for governments to know, and show that it may be socially optimal to limit and sometimes to eliminate individual choice. As an example, we apply Luce’s (1959) model of random choice to a [...]
To begin to explore the role of biogenic amines in reproductive division of labor in social insects, brain levels of dopamine, serotonin, and octopamine were measured in bumble bee (Bombus terrestris) workers and queens that differ in behavioral and reproductive state. Levels of all three amines were similar for mated and virgin queens. Young workers that developed with or without a queen had similar amine levels, but in queenright colonies differences in biogenic amine levels were associated with differences in behavior and reproductive physiology. Dominant workers had significantly higher octopamine levels compared with workers of lower dominance status but of similar size, age, and ovary state. High dopamine levels were associated with the last stages of oocyte development irrespective of worker social status and behavior. These results suggest that biogenic amines are involved in behavioral and physiological aspects of regulation of reproduction in bumble bees.
Broken symmetry is characteristic of arrays of quantum dots and can be observed in the failure of selection rules of optical spectroscopy or in the dielectric properties. Here we discuss scanning tunneling spectroscopy, where electrons are detached or attached. In the lowest order of description (sometimes known as Koopmans theorem), the orbitals of a system are regarded as given and, one adds or removes electrons from these orbitals. if one has a half-full band of states whose energies have a reflection symmetry about the center, the density of states should be symmetric about the energy of the highest occupied state. Features that are special to arrays of nanodots and lead to the breaking of the expected symmetry are identified. Computations of the density of states of an array of Ag nanodots that are in accord with the available experimental observations are also provided. For a disordered array, the response of the STM probe can be qualitatively different at different lattice points and we interpret this in terms of a change in the nature of the ground electronic state of the array when it is more disordered.
Emerin, MAN1, and LAP2 are integral membrane proteins of the vertebrate nuclear envelope. They share a 43-residue N-terminal motif termed the LEM domain. We found three putative LEM domain genes in Caenorhabditis elegans, designated emr-1, lem-2, and lem-3. We analyzed emr-l, which encodes Ce-emerin, and lem-2, which encodes Ce-MAN1. Ce-emerin and Ce-MAN1 migrate on SDS-PAGE as 17- and 52-kDa proteins, respectively. Based on their biochemical extraction properties and immunolocalization, both Ce-emerin and Ce-MAN1 are integral membrane proteins localized at the nuclear envelope. We used antibodies against Ce-MAN1, Ce-emerin, nucleoporins, and Ce-lamin to determine the timing of nuclear envelope breakdown during mitosis in C. elegans. The C. elegans nuclear envelope disassembles very late compared with vertebrates and Drosophila. The nuclear membranes remained intact everywhere except near spindle poles during metaphase and early anaphase, fully disassembling only during mid-late anaphase. Disassembly of pore complexes, and to a lesser extent the lamina, depended on embryo age: pore complexes were absent during metaphase in >30-cell embryos but existed until anaphase in 2- to 24-cell embryos. Intranuclear mRNA splicing factors disassembled after prophase. The timing of nuclear disassembly in C. elegans is novel and may reflect its evolutionary position between unicellular and more complex eukaryotes.
This paper analyzes the role of finance capital in regional economic development. A cost-benefit approach is invoked in order to estimate the welfare impacts of a regional loan and guarantee program for small firms in Israel. Program-created employment is treated as a benefit and an employment account that separates net from gross employment, is presented. An estimate of net wage benefits is then derived. This involves adjusting wages across different earnings classes in order to account for the variation in opportunity costs of labor at different levels. The estimation of costs includes the opportunity costs of capital, administration, default, and tax-raising costs. Results point to substantial regional welfare effects. We stress the need to account for changing regional economic structure in this kind of evaluation framework.
Structural rearrangements and aggregation resulting from covalent modification of human IgG by caprylic ester of N-hydroxysuccinimide were studied by differential scanning calorimetry, dynamic light scattering, and ANS-binding spectrofluorimetry. The thermogram for the native IgG displays only one transition peak (Tmax = 68°, ΔH = 20.9 J/g). For the chem. modified IgG the temps. corresponding to the initial and maximal deviations of the heat flow as well as the area under the transition peak decreased as the no. of attached alkyl groups increases. This finding may be explained by weakening the intramol. interactions responsible for the rigidity of the IgG mol. structure and by an increase in the protein-protein interactions for the modified IgG. Dynamic light scattering data indicate spontaneous aggregation of the modified IgG mols. in aq. soln.; the size of aggregates depends on the modification degree. These data correlate with a drastic increase in the surface hydrophobicity index for IgG mols. with an increase in the no. of attached alkyl chains. [on SciFinder(R)]
Previous research showed that age-related division of labor in honey bees is associated with changes in activity rhythms; young adult bees perform hive tasks with no daily rhythms, whereas older bees forage with strong daily rhythms. We report that this division of labor is also associated with differences in both circadian rhythms and mRNA levels of period, a gene well known for its role in circadian rhythms. The level of period mRNA in the brain oscillated in bees of all ages, but was significantly higher at all times in foragers, Elevated period mRNA levels cannot be attributed exclusively to aging, because bees induced to forage precociously because of a change in social environment had levels similar to normal age foragers, These results extend the regulation of a ``clock gene'' to a social context and suggest that there are connections at the molecular level between division of labor and chronobiology in social insects.
Fermions need to satisfy the Pauli exclusion principle: no two can be in the same state. This restriction is most compactly expressed in a second quantization formalism by the requirement that the creation and annihilation operators of the electrons satisfy anti-commutation relations. The usual classical limit of quantum mechanics corresponds to creation and annihilation operators that satisfy commutation relations, as for a harmonic oscillator. We discuss a simple classical limit for Fermions. This limit is shown to correspond to an anharmonic oscillator, with just one bound excited state. The vibrational quantum number of this anharmonic oscillator, which is therefore limited to the range 0 to 1, is the classical analog of the quantum mechanical occupancy. This interpretation is also true for Bosons, except that they correspond to a harmonic oscillator so that the occupancy is from 0 up. The formalism is intended to be useful for simulating the behavior of highly correlated Fermionic systems, so the extension to many electron states is also discussed.
The classical limit is shown to provide a description exactly equivalent to the quantum mechanical one in the approximation where each electron is assigned to an orbital. Strictly speaking it is therefore not a limit but an alternative way of solving the problem. There are some merits of this reformulation, most notably in that it brings the phase of the orbitals to the forefront, on equal footing as the occupancies. This allows one to discuss, e.g., electron localization, in a clearer manner. But computationally the classical description is not superior. There will be a definite advantage for more realistic electronic Hamiltonians, i.e., for implementing configuration interaction, and/or when the nuclear motion is coupled to the electronic dynamics. In this paper we limit attention to a derivation and discussion of the simple orbital approximation. (C) 2000 American Institute of Physics. [S0021-9606(00)30435-4].
We exploit nonlinear propagation in photorefractive crystals to observe the phenomenology associated with the collision and interaction of solitons of different tranverse dimensions: a self-trapped stripe and a round soliton. Along with evidence of particlelike behavior, our results indicate the emergence of a new phenomenology related to the hybrid-dimensional system. (C) 2000 Optical Society of America. OCIS codes: 190.5530, 190.5330.
MP2 and CCSD(T) calculations are used to analyse the structures and vibrational spectra of HRgF molecules, where the rare gas atom is He, Ne, Ar, Rr, Xe or Rn. We extend the analysis of the vibrational spectra of these molecules to include anharmonic corrections for the most likely candidates for experimental detection, i.e., HArF, HKrF, HXeF, and their deuterated isotopomers. The anharmonic correlation-corrected vibrational self-consistent-field (CC-VSCF) calculations are used for this, and fundamental, overtone and combination frequencies and their absorption intensities are computed. (C) 2000 Elsevier Science B.V. All rights reserved.
Charge transport in molecular and extended systems is discussed with special reference to the mixing of covalent and ionic states and the evolution of this mixing with time. The formalism allows the electron to acquire an extra phase when it moves from one site to the next so that a hopping limit can be reached where the electron transfers with a random phase. The equations of motion are solved for both quantum mechanical and classical dynamics. An appendix discusses a classical representation of orbital occupancies in a manner consistent with the Pauli exclusion principle.
The present invention relates to a pharmaceutical cream composition for topical application for the treatment of skin disorders and skin diseases, comprising 1-6 wt.% Dead Sea Mud as an active ingredient. Said composition is for use in treating skin disorders and skin diseases such as psoriasis, saborrehic dermatitis, xerosis, atopic dermatitis, eczema, diaper rash, skin burns of state I and sensitive skin. Said cream composition is also for use as a leave-on cosmetic cream for beautifying and enhancing the skin appearance. In addition to Dead Sea Mud said composition comprises ingredients suitable for the preparation of cosmetic cream. Said cream can further comprise up to 4 wt.% Dead Sea water. [on SciFinder(R)]
Lay summary:
The article applies theory about high-performance teams, developed in the private sector, to public sector teams tasked with implementing IT projects. The article compares two different forms of project teams: work groups committees. It proposes that work groups are more effective at ensuring project implementation. Drawing on 2 case studies the article provides general lessons on staffing, structuring and supervising public sector IT workgroups.
Publication significance:
The smooth governance of a country depends on efficient public sector IT project implementation. Yet, the public sector consistently lags behind private sector technological efficiency. The article addresses this critical challenge to public sector legitimacy. The article compares two team project models, the workgroup and the committee, and presents important findings that provide insight into the design and implementation of effective public sector team projects.
Presents an overview to articles on morphological processing published in the periodical 'Language and Cognitive Processes,' volume 15, 2000. Garnering of evidence from Hebrew, French, Italian, Spanish, Catalan, Dutch, German, Finnish, Chinese and English languages; Ecological validity of models of word recognition; Focus on cognitive processes within the visual modality.
Thermionic emission is discussed as a long time (microseconds) decay mode of energy-rich large molecules, metallic and metcar clusters, and fullerenes. We review what is known and consider the many experiments, systems, and theoretical and computational studies that still need to be done. We conclude with a wish list for future work. Particular attention is given to the experimental signatures, such as the dependence on the mode of energy acquisition, and theoretical indications of a not-quite-statistical delayed ionization and to the competition of electron emission with other decay modes, such as fragmentation or radiative cooling. Coupling of the electronic and nuclear modes can be a bottleneck and quite long time-delayed ionization can be observed, as in the decay of high Rydberg states probed by ZEKE spectroscopy, before the onset of complete energy partitioning.
