The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents

This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative

Two-particle Kapitza-Dirac diffraction

We extend the study of Kapitza-Dirac diffraction to the case of two-particle systems. Due to the exchange effects the shape and visibility of the two-particle detection patterns show important differences for identical and distinguishable particles. We also identify a novel quantum statistics effect present in momentum space for some values of the initial particle momenta, which is associated with different numbers of photon absorptions compatible with the final momenta.Comment: Minor changes with the published versio

Quantum description and properties of electrons emitted from pulsed nanotip electron sources

We present a quantum calculation of the electron degeneracy for electron sources. We explore quantum interference of electrons in the temporal and spatial domain and demonstrate how it can be utilized to characterize a pulsed electron source. We estimate effects of Coulomb repulsion on two-electron interference and show that currently available nano tip pulsed electron sources operate in the regime where the quantum nature of electrons can be made dominant

Regulation of Synaptic Pumilio Function by an Aggregation-Prone Domain

We identified Pumilio (Pum), a Drosophila translational repressor, in a computational search for metazoan proteins whose activities might be regulated by assembly into ordered aggregates. The search algorithm was based on evolutionary sequence conservation patterns observed for yeast prion proteins, which contain aggregation-prone glutamine/asparagine (Q/N)-rich domains attached to functional domains of normal amino acid composition. We examined aggregation of Pum and its nematode ortholog PUF-9 by expression in yeast. A domain of Pum containing the Q/N-rich sequence, denoted as NQ1, the entire Pum N terminus, and the complete PUF-9 protein localize to macroscopic aggregates (foci) in yeast. NQ1 and PUF-9 can generate the yeast Pin+ trait, which is transmitted by a heritable aggregate. NQ1 also assembles into amyloid fibrils in vitro. In Drosophila, Pum regulates postsynaptic translation at neuromuscular junctions (NMJs). To assess whether NQ1 affects synaptic Pum activity in vivo, we expressed it in muscles. We found that it negatively regulates endogenous Pum, producing gene dosage-dependent pum loss-of-function NMJ phenotypes. NQ1 coexpression also suppresses lethality and NMJ phenotypes caused by overexpression of Pum in muscles. The Q/N block of NQ1 is required for these phenotypic effects. Negative regulation of Pum by NQ1 might be explained by formation of inactive aggregates, but we have been unable to demonstrate that NQ1 aggregates in Drosophila. NQ1 could also regulate Pum by a "dominant-negative" effect, in which it would block Q/N-mediated interactions of Pum with itself or with cofactors required for translational repression

Nonlocal Phases of Local Quantum Mechanical Wavefunctions in Static and Time-Dependent Aharonov-Bohm Experiments

We show that the standard Dirac phase factor is not the only solution of the gauge transformation equations. The full form of a general gauge function (that connects systems that move in different sets of scalar and vector potentials), apart from Dirac phases also contains terms of classical fields that act nonlocally (in spacetime) on the local solutions of the time-dependent Schr\"odinger equation: the phases of wavefunctions in the Schr\"odinger picture are affected nonlocally by spatially and temporally remote magnetic and electric fields, in ways that are fully explored. These contributions go beyond the usual Aharonov-Bohm effects (magnetic or electric). (i) Application to cases of particles passing through static magnetic or electric fields leads to cancellations of Aharonov-Bohm phases at the observation point; these are linked to behaviors at the semiclassical level (to the old Werner & Brill experimental observations, or their "electric analogs" - or to recent reports of Batelaan & Tonomura) but are shown to be far more general (true not only for narrow wavepackets but also for completely delocalized quantum states). By using these cancellations, certain previously unnoticed sign-errors in the literature are corrected. (ii) Application to time-dependent situations provides a remedy for erroneous results in the literature (on improper uses of Dirac phase factors) and leads to phases that contain an Aharonov-Bohm part and a field-nonlocal part: their competition is shown to recover Relativistic Causality in earlier "paradoxes" (such as the van Kampen thought-experiment), while a more general consideration indicates that the temporal nonlocalities found here demonstrate in part a causal propagation of phases of quantum mechanical wavefunctions in the Schr\"odinger picture. This may open a direct way to address time-dependent double-slit experiments and the associated causal issuesComment: 49 pages, 1 figure, presented in Conferences "50 years of the Aharonov-Bohm effect and 25 years of the Berry's phase" (Tel Aviv and Bristol), published in Journ. Phys. A. Compared to the published paper, this version has 17 additional lines after eqn.(14) for maximum clarity, and the Abstract has been slightly modified and reduced from the published 2035 characters to the required 1920 character

Some genus 3 curves with many points

Using an explicit family of plane quartic curves, we prove the existence of a genus 3 curve over any finite field of characteristic 3 whose number of rational points stays within a fixed distance from the Hasse-Weil-Serre upper bound. We also provide an intrinsic characterization of so-called Legendre elliptic curves

Topological phase for entangled two-qubit states and the representation of the SO(3)group

We discuss the representation of the $SO(3)$ group by two-qubit maximally entangled states (MES). We analyze the correspondence between $SO(3)$ and the set of two-qubit MES which are experimentally realizable. As a result, we offer a new interpretation of some recently proposed experiments based on MES. Employing the tools of quantum optics we treat in terms of two-qubit MES some classical experiments in neutron interferometry, which showed the $\pi$-phase accrued by a spin-$1/2$ particle precessing in a magnetic field. By so doing, we can analyze the extent to which the recently proposed experiments - and future ones of the same sort - would involve essentially new physical aspects as compared with those performed in the past. We argue that the proposed experiments do extend the possibilities for displaying the double connectedness of $SO(3)$, although for that to be the case it results necessary to map elements of $SU(2)$ onto physical operations acting on two-level systems.Comment: 25 pages, 9 figure