342 research outputs found
Hydraulic redistribution: limitations for plants in saline soils
Hydraulic redistribution (HR), the movement of water from wet to dry patches in the soil via roots, occurs in different ecosystems and plant species. By extension of the principle that HR is driven by gradients in soil water potential, HR has been proposed to occur for plants in saline soils. Despite the inherent spatial patchiness and salinity gradients in these soils, the lack of direct evidence of HR in response to osmotic gradients prompted us to ask the question: are there physical or physiological constraints to HR for plants in saline environments? We propose that build-up of ions in the root xylem sap and in the leaf apoplast, with the latter resulting in a large predawn disequilibrium of water potential in shoots compared with roots and soil, would both impede HR. We present a conceptual model that illustrates how processes in root systems in heterogeneous salinity with water potential gradients, even if equal to those in non-saline soils, will experience a dampened magnitude of water potential gradients in the soil–plant continuum, minimizing or preventing HR. Finally, we provide an outlook for understanding the relevance of HR for plants in saline environments by addressing key research questions on plant salinity toleranc
Non-Abelian (p,q) Strings in the Warped Deformed Conifold
We calculate the tension of -strings in the warped deformed conifold
using the non-Abelian DBI action. In the large flux limit, we find exact
agreement with the recent expression obtained by Firouzjahi, Leblond and
Henry-Tye up to and including order terms if is also taken to be
large. Furthermore using the finite prescription for the symmetrised trace
operation we anticipate the most general expression for the tension valid for
any . We find that even in this instance, corrections to the tension
scale as which is not consistent with simple Casimir scaling.Comment: 18 pages, Latex, 1 figure; Added a discussion of the case when the
warp factor parameter and typos correcte
Canine distemper virus ISCOMS induce protection in harbour seals (Phoca vitulina) against phocid distemper but still allow subsequent infection with phocid distemper virus-1.
A candidate canine distemper virus (CDV) ISCOM vaccine has been shown to be effective in protecting harbour seals (Phoca vitulina) from phocid distemper in 1988. However, of the 35 harbour seals receiving this vaccine upon admission to a seal rehabilitation and research centre (Pieterburen, The Netherlands) in 1989, six developed mild inflammatory symptoms of the respiratory tract. Phocid distemper virus-1 (PDV-1) could be isolated from three of these animals. This indicates that the vaccine affords protection from phocid distemper, but may still allow PDV-1 infection of the respiratory tract. Contacts with non-vaccinated seals should then be prevented until no more virus is excreted. It is speculated that this PDV-1 infection of the respiratory tract in CDV-ISCOM vaccinated seals is followed by a lifelong immunity
Efficient Resolution of Anisotropic Structures
We highlight some recent new delevelopments concerning the sparse
representation of possibly high-dimensional functions exhibiting strong
anisotropic features and low regularity in isotropic Sobolev or Besov scales.
Specifically, we focus on the solution of transport equations which exhibit
propagation of singularities where, additionally, high-dimensionality enters
when the convection field, and hence the solutions, depend on parameters
varying over some compact set. Important constituents of our approach are
directionally adaptive discretization concepts motivated by compactly supported
shearlet systems, and well-conditioned stable variational formulations that
support trial spaces with anisotropic refinements with arbitrary
directionalities. We prove that they provide tight error-residual relations
which are used to contrive rigorously founded adaptive refinement schemes which
converge in . Moreover, in the context of parameter dependent problems we
discuss two approaches serving different purposes and working under different
regularity assumptions. For frequent query problems, making essential use of
the novel well-conditioned variational formulations, a new Reduced Basis Method
is outlined which exhibits a certain rate-optimal performance for indefinite,
unsymmetric or singularly perturbed problems. For the radiative transfer
problem with scattering a sparse tensor method is presented which mitigates or
even overcomes the curse of dimensionality under suitable (so far still
isotropic) regularity assumptions. Numerical examples for both methods
illustrate the theoretical findings
Rotating spin-1 bosons in the lowest Landau level
We present results for the ground states of a system of spin-1 bosons in a
rotating trap. We focus on the dilute, weakly interacting regime, and restrict
the bosons to the quantum states in the lowest Landau level (LLL) in the plane
(disc), sphere or torus geometries. We map out parts of the zero temperature
phase diagram, using both exact quantum ground states and LLL mean field
configurations. For the case of a spin-independent interaction we present exact
quantum ground states at angular momentum . For general values of the
interaction parameters, we present mean field studies of general ground states
at slow rotation and of lattices of vortices and skyrmions at higher rotation
rates. Finally, we discuss quantum Hall liquid states at ultra-high rotation.Comment: 24 pages, 14 figures, RevTe
Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
The charged pion form factor, Fpi(Q^2), is an important quantity which can be
used to advance our knowledge of hadronic structure. However, the extraction of
Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is
inherently model dependent. Therefore, a detailed description of the extraction
of the charged pion form factor from electroproduction data obtained recently
at Jefferson Lab is presented, with particular focus given to the dominant
uncertainties in this procedure. Results for Fpi are presented for
Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically
below the monopole parameterization that describes the low Q^2 data used to
determine the pion charge radius. The pion form factor can be calculated in a
wide variety of theoretical approaches, and the experimental results are
compared to a number of calculations. This comparison is helpful in
understanding the role of soft versus hard contributions to hadronic structure
in the intermediate Q^2 regime.Comment: 18 pages, 11 figure
Evidence supports prediabetes treatment
In his News Feature on prediabetes (“Dubious diagnosis,” 8 March, p. 1026), C. Piller asserts that prediabetes diagnoses and treatment may be ineffective and sullied by conflicts of interest. As current and former chairs of the American Diabetes Association’s (ADA’s) Professional Practice Committee [the group that reviews and updates the Standards of Medical Care in Diabetes (Standards) each year], we disagree. Prediabetes is a useful term to convey future risk of diabetes, and recommendations for diabetes prevention are based on best current evidence
Generation of multi-leukemia antigen-specific T cells to enhance the graft-versus-leukemia effect after allogeneic stem cell transplant
Adoptive immunotherapy with ex vivo expanded T cells is a promising approach to prevent or treat leukemia. Myeloid leukemias express tumor-associated antigens (TAA) that induce antigen-specific cytotoxic T lymphocyte (CTL) responses in healthy individuals. We explored the feasibility of generating TAA-specific CTLs from stem cell donors of patients with myeloid leukemia to enhance the graft-versus-leukemia effect after stem cell transplantation. CTL lines were manufactured from peripheral blood of 10 healthy donors by stimulation with 15mer peptide libraries of five TAA (proteinase 3 (Pr3), preferentially expressed antigen in melanoma, Wilms tumor gene 1 (WT1), human neutrophil elastase (NE) and melanoma-associated antigen A3) known to be expressed in myeloid leukemias. All CTL lines responded to the mix of five TAA and were multi-specific as assessed by interferon-γ enzyme-linked immunospot. Although donors showed individual patterns of antigen recognition, all responded comparably to the TAAmix. Immunogenic peptides of WT1, Pr3 or NE could be identified by epitope mapping in all donor CTL lines. In vitro experiments showed recognition of partially human leukocyte antigen (HLA)-matched myeloid leukemia blasts. These findings support the development of a single clinical grade multi-tumor antigen-specific T-cell product from the stem cell source, capable of broad reactivity against myeloid malignancies for use in donor-recipient pairs without limitation to a certain HLA-type
Christopher Lasch's the culture of narcissism the failure of a critique of psychological politics
Christopher Lasch's bestseller The Culture of Narcissism had, beyond doubt, a significant impact-it was even read in the White House. Today it is not only still frequently taught and referenced, there are also still empirical studies conducted which try to verify Lasch's assertion of the preponderance of the narcissistic personality. This paper re-reads the book as a critique of psychologization processes, and this allows us to discern, besides the flaws in Lasch's approach, a fundamental insight which goes largely unnoticed by both Lasch's opponents and his proponents. Following this, the article will situate subjectivity within the matrix of psychology, science, psychoanalysis, and politics. In this way a critique of contemporary forms of psychologization-psychologization under globalization, as it were-is made possible
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