994 research outputs found

    K-Knuth Equivalence for Increasing Tableaux

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    A K-theoretic analogue of RSK insertion and Knuth equivalence relations was first introduced in 2006 by Buch, Kresch, Shimozono, Tamvakis, and Yong. The resulting K-Knuth equivalence relations on words and increasing tableaux on [n] has prompted investigation into the equivalence classes of tableaux arising from these relations. Of particular interest are the tableaux that are unique in their class, which we refer to as unique rectification targets (URTs). In this paper we give several new families of URTs and a bound on the length of intermediate words connecting two K-Knuth equivalent words. In addition, we describe an algorithm to determine if two words are K-Knuth equivalent and to compute all K-Knuth equivalence classes of tableaux on [n].Comment: 35 page

    Structure of exotic three-body systems

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    The classification of large halos formed by two identical particles and a core is systematically addressed according to interparticle distances. The root-mean-square distances between the constituents are described by universal scaling functions obtained from a renormalized zero-range model. Applications for halo nuclei, 11^{11}Li and 14^{14}Be, and for atomic 4^4He3_3 are briefly discussed. The generalization to four-body systems is proposed.Comment: Contribution to the International workshop "Critical Stability of Few-Body Quantum Systems". To be published in "Few-Body Systems

    A chemical genetic approach reveals distinct EphB signaling mechanisms during brain development.

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    EphB receptor tyrosine kinases control multiple steps in nervous system development. However, it remains unclear whether EphBs regulate these different developmental processes directly or indirectly. In addition, given that EphBs signal through multiple mechanisms, it has been challenging to define which signaling functions of EphBs regulate particular developmental events. To address these issues, we engineered triple knock-in mice in which the kinase activity of three neuronally expressed EphBs can be rapidly, reversibly and specifically blocked. We found that the tyrosine kinase activity of EphBs was required for axon guidance in vivo. In contrast, EphB-mediated synaptogenesis occurred normally when the kinase activity of EphBs was inhibited, suggesting that EphBs mediate synapse development by an EphB tyrosine kinase-independent mechanism. Taken together, our data indicate that EphBs control axon guidance and synaptogenesis by distinct mechanisms and provide a new mouse model for dissecting EphB function in development and disease

    Quality attributes of pistachio nuts as affected by rootstocks and deficit irrigation

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    BACKGROUND: In this work, the influence of two regulated deficit irrigation (RDI) treatments and three different rootstocks on the quality of pistachios was evaluated by analyzing different parameters: morphological analysis, physicochemical analysis and sensory analysis. RESULTS: The results obtained in terms of the choice of rootstock revealed that Pistacia atlantica had increased production yields, nut weight, mineral content, higher intensities of characteristic sensory attributes and a higher degree of consumer satisfaction, than the other rootstocks studied. Moreover, the results established that the application of RDI on pistachio cultivation had no significant influence on production yield, weight, size, colour, water activity or mineral composition. Furthermore, T1 treatment (stem water potential?<?-1.3 MPa) resulted in higher intensities of characteristic sensory attributes and a greater level of satisfaction among international consumers. CONCLUSION: These results confirm that the application of deficit irrigation (T1) contributes to an increase in overall product quality. Furthermore, Pistacia atlantica rootstock provided better yield and quality than the other rootstocks studied. © 2014 Society of Chemical Industr

    How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution and Infilling Processes

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    As coastal environments become more susceptible to land loss through accelerating sea level rise and subsidence, new restoration methods harnessing borrowed sediment are more valuable than ever. Mud-capped dredge pits (MCDPs) are a relatively new source of restoration-quality sediment that has only recently been utilized for beach and barrier island restorations in Louisiana. Because MCDPs have been in use for less than two decades in only a handful sites, little is understood about their evolution over decadal timescales. To improve our understanding of MCDPs after they are dredged, we have conducted a suite of geophysical surveys including bathymetry, sidescan sonar, CHIRP subbottom profilers, and magnetometry to monitor Peveto Channel dredge pit, the only infilled dredge pit to date offshore of Holly Beach, Louisiana. Using newly collected and historical data, we are able to better evaluate key components of dredge pit evolution, such as infilling rate and pit margin erosion. Traditional models overestimate the rate at which sediment is deposited into the dredged pit. Additionally, due to the muddy overburden surrounding MCDPs, the pit walls are fairly stable over time, indicating that the walls experience little lateral movement over time. Using new results and knowledge gained from this study, we can better understand how to utilize MCDPs in the future, and better evaluate the current management of offshore sand resources and the regulations regarding setback buffer zones for pipelines and oil infrastructure

    A new type of carbon resistance thermometer with excellent thermal contact at millikelvin temperatures

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    Using a new brand of commercially available carbon resistor we built a cryogenic thermometer with an extremely good thermal contact to its thermal environment. Because of its superior thermal contact the thermometer is insensitive to low levels of spurious radio frequency heating. We calibrated our thermometer down to 5mK using a quartz tuning fork He-3 viscometer and measured its thermal resistance and thermal response time.Comment: 5 pages, 4 figure

    Scaling predictions for radii of weakly bound triatomic molecules

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    The mean-square radii of the molecules 4^4He3_3, 4^4He26_2-^6Li, 4^4He27_2-^7Li and 4^4He223_2-^{23}Na are calculated using a three-body model with contact interactions. They are obtained from a universal scaling function calculated within a renormalized scheme for three particles interacting through pairwise Dirac-delta interaction. The root-mean-square distance between two atoms of mass mAm_A in a triatomic molecule are estimated to be of de order of C2/[mA(E3E2)]{\cal C}\sqrt{\hbar^2/[m_A(E_3-E_2)]}, where E2E_2 is the dimer and E3E_3 the trimer binding energies, and C{\cal C} is a constant (varying from 0.6\sim 0.6 to 1\sim 1) that depends on the ratio between E2E_2 and E3E_3. Considering previous estimates for the trimer energies, we also predict the sizes of Rubidium and Sodium trimers in atomic traps.Comment: 7 pages, 2 figure

    Examining the differential effects of the Mystery Motivator intervention using chosen versus unknown reinforcers

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    Disruptive classroom behaviors are among the most prevalent of childhood problems and are associated with reduced instruction time, poor academic achievement, and persistent behavior problems throughout childhood. Class-wide interventions, such as the Mystery Motivator, are an easy and time efficient way to increase the level of classroom management and remediate disruptive behavior patterns. Although the effectiveness of class-wide interventions is well documented, the literature is still inconsistent as to which type of reinforcement is more effective when using behavioral interventions. Some research suggests individuals prefer a choice in reinforcement, while other research suggests choice is just as preferred as reinforcement without a choice. A multiple baseline design across three elementary school classrooms was used to demonstrate the effects of the Mystery Motivator intervention on disruptive behaviors. Additionally, this study compared the differential effects of using an unknown reinforcer (no choice, or mystery, reinforcement) and a chosen reinforcer. Results showed that the Mystery Motivator intervention was effective in decreasing disruptive behaviors, and this effect was equally effective when using an unknown or a chosen reinforcer
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