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EXPERIENCE WITH CONTROL ROD SEALS USED ON SODIUM-COOLED REACTORS.
Bidirectional synaptic mechanisms of ocular dominance plasticity in visual cortex
As in other mammals with binocular vision, monocular lid suture in mice induces bidirectional plasticity: rapid weakening of responses evoked through the deprived eye followed by delayed strengthening of responses through the open eye. It has been proposed that these bidirectional changes occur through three distinct processes: first, deprived-eye responses rapidly weaken through homosynaptic long-term depression (LTD); second, as the period of deprivation progresses, the modification threshold determining the boundary between synaptic depression and synaptic potentiation becomes lower, favouring potentiation; and third, facilitated by the decreased modification threshold, open-eye responses are strengthened via homosynaptic long-term potentiation (LTP). Of these processes, deprived-eye depression has received the greatest attention, and although several alternative hypotheses are also supported by current research, evidence suggests that α-amino-3- hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor endocytosis through LTD is a key mechanism. The change in modification threshold appears to occur partly through changes in N-methyl-d-aspartate (NMDA) receptor subunit composition, with decreases in the ratio of NR2A to NR2B facilitating potentiation. Although limited research has directly addressed the question of open-eye potentiation, several studies suggest that LTP could account for observed changes in vivo. This review will discuss evidence supporting this three-stage model, along with outstanding issues in the field
DLCQ String Spectrum from SYM Theory
We study non planar corrections to the spectrum of operators in the
supersymmetric Yang Mills theory which are dual to string
states in the maximally supersymmetric pp-wave background with a {\em compact}
light-cone direction. The existence of a positive definite discrete light-cone
momentum greatly simplifies the operator mixing problem. We give some examples
where the contribution of all orders in non-planar diagrams can be found
analytically. On the string theory side this corresponds to finding the
spectrum of a string state to all orders in string loop corrections.Comment: 35 pages, no figure
Divergence Cancellation and Loop Corrections in String Field Theory on a Plane Wave Background
We investigate the one-loop energy shift E to certain two-impurity string
states in light-cone string field theory on a plane wave background. We find
that there exist logarithmic divergences in the sums over intermediate mode
numbers which cancel between the cubic Hamiltonian and quartic ``contact
term''. Analyzing the impurity non-conserving channel we find that the
non-perturbative, order g_2^2 sqrt(lambda') contribution to E/mu predicted in
hep-th/0211220 is in fact an artifact of these logarithmic divergences and
vanishes with them, leaving an order g_2^2 lambda' contribution. Exploiting the
supersymmetry algebra, we present a form for the energy shift which appears to
be manifestly convergent and free of non-perturbative terms. We use this form
to argue that E/mu receives order g_2^2 lambda' contributions at every order in
intermediate state impurities.Comment: 27 pages; added references, acknowledgments, missing normalization in
equations 2.3 - 2.8, also cleaned up notation, and added a few footnote
Fermion Representation Of The Rolling Tachyon Boundary Conformal Field Theory
A free fermion representation of the rolling tachyon boundary conformal field
theory is constructed. The representation is used to obtain an explicit,
compact, exact expression for the boundary state. We use the boundary state to
compute the disc and cylinder amplitudes for the half-S-brane.Comment: 27 page
The superstring Hagedorn temperature in a pp-wave background
The thermodynamics of type IIB superstring theory in the maximally
supersymmetric plane wave background is studied. We compute the thermodynamic
partition function for non-interacting strings exactly and the result differs
slightly from previous computations. We clarify some of the issues related to
the Hagedorn temperature in the limits of small and large constant RR 5-form.
We study the thermodynamic behavior of strings in the case of geometries in the presence of NS-NS and RR 3-form backgrounds. We
also comment on the relationship of string thermodynamics and the thermodynamic
behavior of the sector of Yang-Mills theory which is the holographic dual of
the string theory.Comment: 22 pages, JHEP style, minor misprints corrected, some comments adde
Pathogenic Fungi Regulate Immunity by Inducing Neutrophilic Myeloid-Derived Suppressor Cells
Peer reviewedPublisher PD
Disease and treatment-related burden in patients with acromegaly who are biochemically controlled on injectable somatostatin receptor ligands
Medical treatment for acromegaly commonly involves receiving intramuscular or deep subcutaneous injections of somatostatin receptor ligands (SRLs) in most patients. In addition to side effects of treatment, acromegaly patients often still experience disease symptoms even when therapy is successful in controlling GH and IGF-1 levels. Symptoms and side effects can negatively impact patients' health-related quality of life. In this study, we examine the disease- and treatment-related burden associated with SRL injections as reported through the use of the Acromegaly Treatment Satisfaction Questionnaire (Acro-TSQ(C)) and clinician-reported symptom severity through the Acromegaly Index of Severity (AIS). Patients included in this analysis were enrolled in a randomized phase 3 study, were biochemically-controlled (an IGF-1 = 6 months with a stable dose of either long- acting octreotide or lanreotide monotherapy for >= 4 months. The sample (N = 91) was 65% female, 91% Caucasian, with a mean [standard deviation (SD)] age of 53 (1) years. Two-thirds of patients reported that they still experience acromegaly symptoms; 82% of these said they experience symptoms all of the time. Three-fourths experienced gastrointestinal (GI) side effects after injections, and 77% experienced treatment-related injection site reactions (ISRs). Patients commonly reported that these interfered with their daily life, leisure, and work activities. Those with higher symptom severity, as measured by the AIS, scored significantly worse on several Acro-TSQ domains: Symptom Interference, GI Interference, Treatment Satisfaction, and Emotional Reaction. Despite being biochemically controlled with injectable SRLs, most patients reported experiencing acromegaly symptoms that interfere with daily life, leisure, and work. GI side effects and ISRs were also common. This study highlights the significant disease burden that still persists for patients with acromegaly that have achieved biochemical control with the use of injectable SRLs.Diabetes mellitus: pathophysiological changes and therap
Fuzzy cluster validation using the partition negentropy criterion
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-04277-5_24Proceedings of the 19th International Conference, Limassol, Cyprus, September 14-17, 2009We introduce the Partition Negentropy Criterion (PNC) for cluster validation. It is a cluster validity index that rewards the average normality of the clusters, measured by means of the negentropy, and penalizes the overlap, measured by the partition entropy. The PNC is aimed at finding well separated clusters whose shape is approximately Gaussian. We use the new index to validate fuzzy partitions in a set of synthetic clustering problems, and compare the results to those obtained by the AIC, BIC and ICL criteria. The partitions are obtained by fitting a Gaussian Mixture Model to the data using the EM algorithm. We show that, when the real clusters are normally distributed, all the criteria are able to correctly assess the number of components, with AIC and BIC
allowing a higher cluster overlap. However, when the real cluster distributions are not Gaussian (i.e. the distribution assumed by the mixture model) the PNC outperforms the other indices, being able to correctly
evaluate the number of clusters while the other criteria (specially AIC and BIC) tend to overestimate it.This work has been partially supported with funds from
MEC BFU2006-07902/BFI, CAM S-SEM-0255-2006 and CAM/UAM project CCG08-UAM/TIC-442
Coupling climate and economic models in a cost-benefit framework: a convex optimization approach
In this paper we present a general method, based on a convex optimisation technique, that facilitates the coupling of climate and economic models in a cost-benefit framework. As a demonstration of the method, we couple an economic growth model à la Ramsey adapted from DICE-99 with an efficient intermediate complexity climate model, C-GOLDSTEIN, which has highly simplified physics, but fully 3-D ocean dynamics. As in DICE-99 we assume that an economic cost is associated with global temperature change: this change is obtained from the climate model which is driven by the GHG concentrations computed from the economic growth path. The work extends a previous paper in which these models were coupled in cost-effectiveness mode. Here we consider the more intricate cost-benefit coupling in which the climate impact is not fixed a priori. We implement the coupled model using an oracle-based optimisation technique. Each model is contained in an oracle which supplies model output and information on its sensitivity to a master program. The algorithm Proximal-ACCPM guarantees the convergence of the procedure under sufficient convexity assumptions. Our results demonstrate the possibility of a consistent, cost-benefit, climate-damage optimisation analysis with a 3-D climate model
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