1,788 research outputs found
The Effect of Iron Deficiency on the Absorption and Translocation of Iron and Phosphorus by Soybean Plants
Reduction of Some 2-Thiazoline Benzamide and Carbamate Derivatives with Lithium Aluminum Hydride
This paper r eports the reduction with litMum aluminum
hydride of 2-benzamido-5-methyl-2-thiazoline (Va) and 2-benzamido-
5,5-dimethyl-2-thiazo1\u27ine (Vb) to give the corresponding
2-benzyfamino-2-thiazolines (Via, b), and of ethyl N-(5-methyl-2-
-thiazoline-2-yl)-carbamate (Ila) and ethyl N-(5,5-dimethyl-2-thiazoline-
2-yl)-carbamate (Ilb) to give the corresponding 2-methylamino-
2-thiazolines (Illa, b). No evidence of ring reduction or cleavage was
observed either at room temperature or in refluxing ether or tetrahydrofuran.
The structure of the products was confirmed by independent
syntheses. Characteristic infrared bands ar e described
Learning to mentalize: a mediational approach for caregivers and therapists
Mentalization-based therapies (MBTs) are rigorous, theoretically grounded, and evidence-based
interventions. However, dissemination of this psychodynamically informed intervention lags behind
that of more skills-based therapies because of a lack of concrete operationalization of its key
components. In this proof-of-concept paper, we describe how the learning (mediational)
components of an educational intervention, the Mediational Intervention for Sensitizing Caregivers
(MISC), can operationalize key components of MBTs in behaviorally anchored ways. We suggest
that the process of the recovery of mentalizing can be operationalized through five learning
components: focusing, affecting, expanding, rewarding, and regulating. In operationalizing the
process of rebuilding mentalizing using these observable, behaviorally anchored concepts focusing
on creating epistemic trust, we hope to increase the accessibility of MBTs to a wider audience
Power-Based Droop Control in DC Microgrids Enabling Seamless Disconnection From Upstream Grids
This paper proposes a local power-based droop controller for distributed energy resource converters in dc microgrids that are connected to upstream grids by grid-interface converters. During normal operation, the grid-interface converter imposes the microgrid bus voltage, and the proposed controller allows power flow regulation at distributed energy resource converters\u2019 output. On the other hand, during abnormal operation of the grid-interface converter (e.g., due to faults in the upstream grid), the proposed controller allows bus voltage regulation by droop control. Notably, the controller can autonomously convert from power flow control to droop control, without any need of bus voltage variation detection schemes or communication with other microgrid components, which enables seamless transitions between these two modes of operation. Considering distributed energy resource converters employing the power-based droop control, the operation modes of a single converter and of the whole microgrid are defined and investigated herein. The controller design is also introduced. Furthermore, the power sharing performance of this control approach is analyzed and compared with that of classical droop control. The experimental results from a laboratory-scale dc microgrid prototype are reported to show the final performances of the proposed power-based droop control
Glassy Random Matrix Models
This paper discusses Random Matrix Models which exhibit the unusual phenomena
of having multiple solutions at the same point in phase space. These matrix
models have gaps in their spectrum or density of eigenvalues. The free energy
and certain correlation functions of these models show differences for the
different solutions. Here I present evidence for the presence of multiple
solutions both analytically and numerically.
As an example I discuss the double well matrix model with potential where is a random matrix (the
matrix model) as well as the Gaussian Penner model with . First I study what these multiple solutions are in the large
limit using the recurrence coefficient of the orthogonal polynomials.
Second I discuss these solutions at the non-perturbative level to bring out
some differences between the multiple solutions. I also present the two-point
density-density correlation functions which further characterizes these models
in a new university class. A motivation for this work is that variants of these
models have been conjectured to be models of certain structural glasses in the
high temperature phase.Comment: 25 pages, Latex, 7 Figures, to appear in PR
A unified fluctuation formula for one-cut -ensembles of random matrices
Using a Coulomb gas approach, we compute the generating function of the
covariances of power traces for one-cut -ensembles of random matrices in
the limit of large matrix size. This formula depends only on the support of the
spectral density, and is therefore universal for a large class of models. This
allows us to derive a closed-form expression for the limiting covariances of an
arbitrary one-cut -ensemble. As particular cases of the main result we
consider the classical -Gaussian, -Wishart and -Jacobi
ensembles, for which we derive previously available results as well as new ones
within a unified simple framework. We also discuss the connections between the
problem of trace fluctuations for the Gaussian Unitary Ensemble and the
enumeration of planar maps.Comment: 16 pages, 4 figures, 3 tables. Revised version where references have
been added and typos correcte
Ice-lens formation and geometrical supercooling in soils and other colloidal materials
We present a new, physically-intuitive model of ice-lens formation and growth
during the freezing of soils and other dense, particulate suspensions.
Motivated by experimental evidence, we consider the growth of an ice-filled
crack in a freezing soil. At low temperatures, ice in the crack exerts large
pressures on the crack walls that will eventually cause the crack to split
open. We show that the crack will then propagate across the soil to form a new
lens. The process is controlled by two factors: the cohesion of the soil, and
the geometrical supercooling of the water in the soil; a new concept introduced
to measure the energy available to form a new ice lens. When the supercooling
exceeds a critical amount (proportional to the cohesive strength of the soil) a
new ice lens forms. This condition for ice-lens formation and growth does not
appeal to any ad hoc, empirical assumptions, and explains how periodic ice
lenses can form with or without the presence of a frozen fringe. The proposed
mechanism is in good agreement with experiments, in particular explaining
ice-lens pattern formation, and surges in heave rate associated with the growth
of new lenses. Importantly for systems with no frozen fringe, ice-lens
formation and frost heave can be predicted given only the unfrozen properties
of the soil. We use our theory to estimate ice-lens growth temperatures
obtaining quantitative agreement with the limited experimental data that is
currently available. Finally we suggest experiments that might be performed in
order to verify this theory in more detail. The theory is generalizable to
complex natural-soil scenarios, and should therefore be useful in the
prediction of macroscopic frost heave rates.Comment: Submitted to PR
Parametric Constructionist Kits: Physical Design and Delivery System for Rapid Prototyping Devices
Cortical Bone Trajectory Screw Placement Accuracy with a Patient-Matched 3-Dimensional Printed Guide in Lumbar Spinal Surgery: A Clinical Study
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