Experimental Demonstration of Greenberger-Horne-Zeilinger Correlations Using Nuclear Magnetic Resonance

The Greenberger-Horne-Zeilinger (GHZ) effect provides an example of quantum correlations that cannot be explained by classical local hidden variables. This paper reports on the experimental realization of GHZ correlations using nuclear magnetic resonance (NMR). The NMR experiment differs from the originally proposed GHZ experiment in several ways: it is performed on mixed states rather than pure states; and instead of being widely separated, the spins on which it is performed are all located in the same molecule. As a result, the NMR version of the GHZ experiment cannot entirely rule out classical local hidden variables. It nonetheless provides an unambiguous demonstration of the "paradoxical" GHZ correlations, and shows that any classical hidden variables must communicate by non-standard and previously undetected forces. The NMR demonstration of GHZ correlations shows the power of NMR quantum information processing techniques for demonstrating fundamental effects in quantum mechanics.Comment: Latex2.09, 8 pages, 1 eps figur

A new population of recently quenched elliptical galaxies in the SDSS

We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue optical colors. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r\geq2.6). These blue ellipticals comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between 10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above 2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the expected quiescent growth at late cosmic time assuming this phase lasts 0.5 Gyr. RQEs have properties that are consistent with a recent merger origin (i.e., they are strong `first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centers of < 3\times 10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale' predicted for maximally efficient spiral merging onto their halo center and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendents may heat the atmospheres of small host halos sufficiently to maintain quenching.Comment: 26 pages, 9 figures. Revised version; accepted for publication in MNRA

Fragile X Mental Retardation 1 and Filamin A Interact Genetically in Drosophila Long-Term Memory

The last decade has witnessed the identification of single-gene defects associated with an impressive number of mental retardation syndromes. Fragile X syndrome, the most common cause of mental retardation for instance, results from disruption of the FMR1 gene. Similarly, Periventricular Nodular Heterotopia, which includes cerebral malformation, epilepsy and cognitive disabilities, derives from disruption of the Filamin A gene. While it remains unclear whether defects in common molecular pathways may underlie the cognitive dysfunction of these various syndromes, defects in cytoskeletal structure nonetheless appear to be common to several mental retardation syndromes. FMR1 is known to interact with Rac, profilin, PAK and Ras, which are associated with dendritic spine defects. In Drosophila, disruptions of the dFmr1 gene impair long-term memory (LTM), and the Filamin A homolog (cheerio) was identified in a behavioral screen for LTM mutants. Thus, we investigated the possible interaction between cheerio and dFmr1 during LTM formation in Drosophila. We show that LTM specifically is defective in dFmr1/cheerio double heterozygotes, while it is normal in single heterozygotes for either dFmr1 or cheerio. In dFmr1 mutants, Filamin (Cheerio) levels are lower than normal after spaced training. These observations support the notion that decreased actin cross-linking may underlie the persistence of long and thin dendritic spines in Fragile X patients and animal models. More generally, our results represent the first demonstration of a genetic interaction between mental retardation genes in an in vivo model system of memory formation

Combinando tecnología video digital y métodos narrativos para comprender el desarrollo infantil

Mit zunehmender Verbesserung der Technologie ergeben sich neue Möglichkeiten, Forschungsvorhaben durchzuführen. Dieser Aufsatz beschreibt die Anwendung der Videobearbeitungssoftware Adobe Premiere in der qualitativen Forschung. Zur Veranschaulichung der Vor- und Nachteile dieses neuen Tools für qualitative Beobachtungsstudien verwenden wir Beispiele aus unseren Untersuchungen über Mutter-Säuglings-Beziehungen. Die Vorteile in der Anwendung von Videobearbeitungssoftware liegen in der Art und Weise, wie Datenmaterial strukturiert, präsentiert und bearbeitet werden kann, was bis dato so nicht möglich war. Indem nur die Videosegmente, die für die Studie relevant sind, aufgezeichnet und chronologisch geordnet werden können, wird es möglich, Filme zusammenzustellen, die von der Größe her gut handhabbar sind und die zu weiteren Analysezwecken relativ einfach weiterverarbeitet werden können. Dies bietet neuartige Wege, um Entwicklungsstadien zu visualisieren und zu analysieren. Des weiteren diskutieren wir den potentiellen Gewinn und ethische Gesichtspunkte, die berücksichtig werden müssen, wenn digitales Videomaterial in Online-Zeitschriften veröffentlich wird. URN: urn:nbn:de:0114-fqs0202245As technology improves, the possibilities for new ways of conducting research emerge. This article focuses on the use of Adobe Premiere video editing software in qualitative research. Examples from our studies of mother-infant relationships will be used to highlight some of the advantages and disadvantages of this new tool in observational, qualitative research. The major benefits of using computer film editing software are that it makes it possible to rearrange, present, and navigate through video in ways never possible before. By capturing segments of video with the types of behavior most relevant for the study, then chronologically ordering the segments into a computer file or a new video, it is possible to create a condense and digestible film to study. This provides a new way to visualize and analyze developmental change. The article also briefly discusses the potential benefits and ethical issues for using digital video in online journals. URN: urn:nbn:de:0114-fqs0202245Al mejorar la tecnología, surgen nuevas posibilidades de conducir investigaciones. Este articulo se enfoca en el uso del software Adobe Premiere que permite editar videos en una investigación cualitativa. Ejemplos de nuestro estudio de las relaciones entre madres e hijos serán usados para destacar algunas de las ventajas y desventajas de esta nueva herramienta en la investigación cualitativa observacional. Los mayores beneficios de usar el software de edición de videos en la computadora son que hacen posible el re-arreglar, presentar y navegar por el video en una forma nunca antes posible. Capturando segmentos del video con los tipos de comportamientos más relevantes para el estudio, y luego ordenando los segmentos cronológicamente en un archivo de computadora o en un nuevo video, es posible crear una película condensada y fácil de estudiar. Esto proporciona una nueva manera de visualizar y analizar el cambio en el desarrollo. Este articulo también discute brevemente los beneficios potenciales y temas éticos al usar videos digitales en diarios de la RED. URN: urn:nbn:de:0114-fqs020224

Experimental Implementation of Projective Measurement in Bell Basis

A scheme for direct projection of a quantum state on Bell states is described. The method is based on constructing an average Hamiltonian with Bell eigenstates and then, projecting the state on these eigenstates. The projection is performed by adding the results of a direct and time-reversed evolution. Experimental demonstration is shown for pairs of dipolar-coupled nuclear spins.Comment: 10 pages, 3 figures, submitte

Structure-activity relationships of pentamidine analogs against Giardia lamblia and correlation of antigiardial activity with DNA-binding affinity.

1,5-Di(4-amidinophenoxy)pentane (pentamidine) and 38 analogs of pentamidine were screened for in vitro activity against the enteric protozoan Giardia lamblia WB (ATCC 30957). All compounds were active against G. lamblia as measured by a [methyl-3H]thymidine incorporation assay. Antigiardial activity varied widely, with 50 % inhibitory concentrations (IC50s) ranging from 0.51 ± 0.13 μM (mean ± standard deviation) for the most active compound to over 100.0 μM for the least active compounds. The IC50of the most potent antigiardial agent.1,5-Di(4-amidinophenoxy)pentane (pentamidine) and 38 analogs of pentamidine were screened for in vitro activity against the enteric protozoan Giardia lamblia WB (ATCC 30957). All compounds were active against G. lamblia as measured by a [methyl-3H]thymidine incorporation assay. Antigiardial activity varied widely, with 50 % inhibitory concentrations (IC50s) ranging from 0.51 ± 0.13 μM (mean ± standard deviation) for the most active compound to over 100.0 μM for the least active compounds. The IC50of the most potent antigiardial agent

Killing them softly:managing pathogen polymorphism and virulence in spatially variable environments

Understanding why pathogen populations are genetically variable is vital because genetic variation fuels evolution, which often hampers disease control efforts. Here I argue that classical models of evolution in spatially variable environments – specifically, models of hard and soft selection – provide a useful framework to understand the maintenance of pathogen polymorphism and the evolution of virulence. First, the similarities between models of hard and soft selection and pathogen life cycles are described, highlighting how the type and timing of pathogen control measures impose density regulation that may affect both the level of pathogen polymorphism and virulence. The article concludes with an outline of potential lines of future theoretical and experimental work

Quantum entanglement and information processing via excitons in optically-driven quantum dots

We show how optically-driven coupled quantum dots can be used to prepare maximally entangled Bell and Greenberger-Horne-Zeilinger states. Manipulation of the strength and duration of the selective light-pulses needed for producing these highly entangled states provides us with crucial elements for the processing of solid-state based quantum information. Theoretical predictions suggest that several hundred single quantum bit rotations and Controlled-Not gates could be performed before decoherence of the excitonic states takes place.Comment: 3 separate PostScript Figures + 7 pages. Typos corrected. Minor changes added. This updated version is to appear in PR

Phosphorylation of Puma modulates its apoptotic function by regulating protein stability

Puma is a potent BH3-only protein that antagonises anti-apoptotic Bcl-2 proteins, promotes Bax/Bak activation and has an essential role in multiple apoptotic models. Puma expression is normally kept very low, but can be induced by several transcription factors including p53, p73, E2F1 and FOXO3a, whereby it can induce an apoptotic response. As Puma can to bind and inactivate all anti-apoptotic members of the Bcl-2 family, its activity must be tightly controlled. We report here, for the first time, evidence that Puma is subject to post-translational control through phosphorylation. We show that Puma is phosphorylated at multiple sites, with the major site of phosphorylation being serine 10. Replacing serine 10 with alanine causes reduced Puma turnover and enhanced cell death. Interestingly, Puma turnover occurs through the proteasome, and substitution of serine 10 causes elevated Puma levels independently of macroautophagy, Bcl-2 family member binding, caspase activity and apoptotic death. We conclude, therefore, that phosphorylation of Puma at serine 10 promotes Puma turnover, represses Puma's cell death potential and promotes cell survival. Owing to the highly pro-apoptotic nature of Puma, these studies highlight an important additional regulatory step in the determination of cellular life or death

Distinct disease mutations in DNMT3A result in a spectrum of behavioral, epigenetic, and transcriptional deficits

Phenotypic heterogeneity in monogenic neurodevelopmental disorders can arise from differential severity of variants underlying disease, but how distinct alleles drive variable disease presentation is not well understood. Here, we investigate missense mutations in DNA methyltransferase 3A (DNMT3A), a DNA methyltransferase associated with overgrowth, intellectual disability, and autism, to uncover molecular correlates of phenotypic heterogeneity. We generate a Dnmt3