2,679 research outputs found

    Full- Scale Load Test of Caisson on Chicago Hardpan

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    The results of a full-scale load test on a belled caisson bearing on hardpan in the downtown Chicago area are presented herein and are discussed in terms of current design practice and the results of other pertinent full-scale tests and a small-scale model test. Current specifications for allowable bearing pressures are shown to be conservative, and previously established settlement limits required to mobilize side resistance are reconfirmed. The settlement measured during the test is in good agreement with that predicted by use of pressuremeter test data. The confinement of the bell in a hard clay layer appears to be beneficial in that it serves to limit the development of major cracking at the base

    Electromagnetic Calorimeter for HADES

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    We propose to build the Electromagnetic calorimeter for the HADES di-lepton spectrometer. It will enable to measure the data on neutral meson production from nucleus-nucleus collisions, which are essential for interpretation of dilepton data, but are unknown in the energy range of planned experiments (2-10 GeV per nucleon). The calorimeter will improve the electron-hadron separation, and will be used for detection of photons from strange resonances in elementary and HI reactions. Detailed description of the detector layout, the support structure, the electronic readout and its performance studied via Monte Carlo simulations and series of dedicated test experiments is presented. The device will cover the total area of about 8 m^2 at polar angles between 12 and 45 degrees with almost full azimuthal coverage. The photon and electron energy resolution achieved in test experiments amounts to 5-6%/sqrt(E[GeV]) which is sufficient for the eta meson reconstruction with S/B ratio of 0.4% in Ni+Ni collisions at 8 AGeV. A purity of the identified leptons after the hadron rejection, resulting from simulations based on the test measurements, is better than 80% at momenta above 500 MeV/c, where time-of-flight cannot be used.Comment: 40 pages, 38 figures version2 - the time schedule added, information about PMTs in Sec.III update

    Picosecond transfer from short-term to long-term memory in analog antiferromagnetic memory device

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    Experiments in materials with a compensated ordering of magnetic moments have demonstrated a potential for approaching the thermodynamic limit of the fastest and least-dissipative operation of a digital memory bit. In addition, these materials are very promising for a construction of energy-efficient analog devices with neuromorphic functionalities, which are inspired by computing-in-memory capabilities of the human brain. In this paper, we report on experimental separation of switching-related and heat-related resistance signal dynamics in memory devices microfabricated from CuMnAs antiferromagnetic metal. We show that the memory variable multilevel resistance can be used as a long-term memory (LTM), lasting up to minutes at room temperature. In addition, ultrafast reflectivity change and heat dissipation from nanoscale-thickness CuMnAs films, taking place on picosecond to hundreds of nanoseconds time scales, can be used as a short-term memory (STM). Information about input stimuli, represented by femtosecond laser pulses, can be transferred from STM to LTM after rehearsals at picosecond to nanosecond times in these memory devices, where information can be retrieved at times up to 10^15 longer than the input pulse duration. Our results open a route towards ultra-fast low-power implementations of spiking neuron and synapse functionalities using a resistive analog antiferromagnetic memory.Comment: 21 pages, 4 figure

    Aintegumenta and Aintegumenta-Like6 regulate auxin-mediated flower development in Arabidopsis

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    <p>Abstract</p> <p>Background</p> <p>Two related genes encoding AP2/ERF-type transcription factors, <it>AINTEGUMENTA </it>(<it>ANT</it>) and <it>AINTEGUMENTA-LIKE6 </it>(<it>AIL6</it>), are important regulators of floral growth and patterning in Arabidopsis. Evidence suggests that these genes promote several aspects of flower development in response to auxin. To investigate the interplay of <it>ANT</it>, <it>AIL6 </it>and auxin during floral development, I have examined the phenotypic consequences of disrupting polar auxin transport in <it>ant</it>, <it>ail6 </it>and <it>ant ail6 </it>mutants by either genetic or chemical means.</p> <p>Results</p> <p>Plants containing mutations in <it>ANT </it>or <it>AIL6 </it>alone or in both genes together exhibit increased sensitivity to disruptions in polar auxin transport. Both genes promote shoot growth, floral meristem initiation and floral meristem patterning in combination with auxin transport. However, differences in the responses of <it>ant </it>and <it>ail6 </it>single mutants to perturbations in auxin transport suggest that these two genes also have non-overlapping activities in each of these developmental processes.</p> <p>Conclusions</p> <p>The enhanced sensitivity of <it>ant </it>and <it>ail6 </it>mutants to alterations in polar auxin transport suggests that these mutants have defects in some aspect of auxin physiology. The inability of <it>ant ail6 </it>double mutants to initiate flowers in backgrounds disrupted for auxin transport confirm the proposed roles for these two genes in floral meristem initiation.</p

    Heisenberg's Uncertainty Relation and Bell Inequalities in High Energy Physics

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    An effective formalism is developed to handle decaying two-state systems. Herewith, observables of such systems can be described by a single operator in the Heisenberg picture. This allows for using the usual framework in quantum information theory and, hence, to enlighten the quantum feature of such systems compared to non-decaying systems. We apply it to systems in high energy physics, i.e. to oscillating meson-antimeson systems. In particular, we discuss the entropic Heisenberg uncertainty relation for observables measured at different times at accelerator facilities including the effect of CP violation, i.e. the imbalance of matter and antimatter. An operator-form of Bell inequalities for systems in high energy physics is presented, i.e. a Bell-witness operator, which allows for simple analysis of unstable systems.Comment: 17 page

    Developmental Robustness by Obligate Interaction of Class B Floral Homeotic Genes and Proteins

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    DEF-like and GLO-like class B floral homeotic genes encode closely related MADS-domain transcription factors that act as developmental switches involved in specifying the identity of petals and stamens during flower development. Class B gene function requires transcriptional upregulation by an autoregulatory loop that depends on obligate heterodimerization of DEF-like and GLO-like proteins. Because switch-like behavior of gene expression can be displayed by single genes already, the functional relevance of this complex circuitry has remained enigmatic. On the basis of a stochastic in silico model of class B gene and protein interactions, we suggest that obligate heterodimerization of class B floral homeotic proteins is not simply the result of neutral drift but enhanced the robustness of cell-fate organ identity decisions in the presence of stochastic noise. This finding strongly corroborates the view that the appearance of this regulatory mechanism during angiosperm phylogeny led to a canalization of flower development and evolution

    Comportamiento del crecimiento de plántulas de cacao (Theobroma cacao L.), en vivero, sembradas en diferentes volúmenes de sustrato

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    The increasing demand for cocoa crops requires high quality plant production. Plants grown in containers or pots have limited nursery survival. The space for root growth and sustrate volume in cacao seedlings in a nursery were tested using diverse plastic containers: tubete (0.4 L), bag (1.6 L) and bucket (3.0 L), the treatments were distributed in a completely random experimental design. Leaf number, width, length; stem and root length; plant height; stem diameter; leaf, stem, root and total fresh weight were evaluated. The cocoa seedlings observed were significantly affected (P≤0.05) by the restriction of space and volume in the root growth area. The highest growth restriction was in the tubete, where container substrate volume is only 1 kg compared with the bag/3 kg and the bucket/5 kg. The development of seedlings grown in tubete was normal until 60 days compared with the bag and the bucket. Abnormal plant growth occurred in the bucket at 120 days and the bag at 90 days.  La creciente demanda del cacao requiere la producción de plantas de alta calidad y su crecimiento en materia, limita su sobrevivencia en vivero. Se evaluó el efecto del espacio de crecimiento radicular y volumen de sustrato sobre el crecimiento de plantas de cacao, empleando diferentes envases plásticos: tubete (0,4 L), bolsa (1,6 L) y balde (3 L) en vivero. Los tratamientos se distribuyeron en un diseño experimental completamente al azar. Los caracteres evaluados fueron: número de hojas, ancho de las hojas, longitud de las hojas, longitud del tallo, longitud de la raíz, altura de la planta, diámetro del tallo, peso fresco de las hojas, peso fresco del tallo, peso fresco de la raíz y peso fresco total. El crecimiento de las plántulas de cacao se vieron afectadas significativamente (P≤0,05) con la reducción del espacio y volumen donde se desarrolla la raíz en etapa de vivero. Se encontró mayor restricción en el crecimiento de la raíz y de estructuras aéreas en el recipiente tubete, donde el volumen de sustrato es únicamente de 1 kg, comparativamente con la bolsa de 3 kg y el balde de 5 kg, acentuándose más esta restricción a través del tiempo. Las plántulas que crecieron en el recipiente de 1 kg se desarrollaron normalmente hasta los 60 días, con una tasa de crecimiento posterior muy baja comparativamente con la bolsa y la matera donde en esta última no se presentó estrés hasta los 120 días ya que contaron con mayor espacio y cantidad de nutrientes. En el caso de la bolsa el incremento la tasa de crecimiento fue muy bajo a partir de los 90 días. 

    'Working out’ identity: distance runners and the management of disrupted identity

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    This article contributes fresh perspectives to the empirical literature on the sociology of the body, and of leisure and identity, by analysing the impact of long-term injury on the identities of two amateur but serious middle/long-distance runners. Employing a symbolic interactionist framework,and utilising data derived from a collaborative autoethnographic project, it explores the role of ‘identity work’ in providing continuity of identity during the liminality of long-term injury and rehabilitation, which poses a fundamental challenge to athletic identity. Specifically, the analysis applies Snow and Anderson’s (1995) and Perinbanayagam’s (2000) theoretical conceptualisations in order to examine the various forms of identity work undertaken by the injured participants, along the dimensions of materialistic, associative and vocabularic identifications. Such identity work was found to be crucial in sustaining a credible sporting identity in the face of disruption to the running self, and in generating momentum towards the goal of restitution to full running fitness and reengagement with a cherished form of leisure. KEYWORDS: identity work, symbolic interactionism, distance running, disrupted identit

    J/psi suppression at forward rapidity in Au+Au collisions at sqrt(s_NN)=39 and 62.4 GeV

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    We present measurements of the J/psi invariant yields in sqrt(s_NN)=39 and 62.4 GeV Au+Au collisions at forward rapidity (1.2<|y|<2.2). Invariant yields are presented as a function of both collision centrality and transverse momentum. Nuclear modifications are obtained for central relative to peripheral Au+Au collisions (R_CP) and for various centrality selections in Au+Au relative to scaled p+p cross sections obtained from other measurements (R_AA). The observed suppression patterns at 39 and 62.4 GeV are quite similar to those previously measured at 200 GeV. This similar suppression presents a challenge to theoretical models that contain various competing mechanisms with different energy dependencies, some of which cause suppression and others enhancement.Comment: 365 authors, 10 pages, 11 figures, 4 tables. Submitted to Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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