1,828 research outputs found
2007-2008 Guest Pianist Weekend - Thomas Hecht
Thomas Hecht Master Class (November 11, 2007) - Progra
Wave functions and their use in spectroscopy and phenomenology
We describe the calculation of Coulomb gauge wave functions for light quark
systems, and their use as interpolating fields for excited state spectroscopy.Comment: 4 pages latex with lat92 macro plus 4 postscript figs, COLO-HEP-29
Phenomenology of the Baryon Resonance 70-plet at Large N_c
We examine the multiplet structure and decay channels of baryon resonances in
the large N_c QCD generalization of the N_c = 3 SU(6) spin-flavor 70. We show
that this ``70'', while a construct of large N_c quark models, actually
consists of five model-independent irreducible spin-flavor multiplets in the
large N_c limit. The preferred decay modes for these resonances fundamentally
depend upon which of the five multiplets to which the resonance belongs. For
example, there exists an SU(3) ``8'' of resonances that is eta-philic and
pi-phobic, and an ``8'' that is the reverse. Moreover, resonances with a strong
SU(3) ``1'' component prefer to decay via a K-bar rather than via a pi.
Remarkably, available data appears to bear out these conclusions.Comment: 26 pages, ReVTe
Feline T-Cell Receptor Îł V- and J-Region Sequences Retrieved from the Trace Archive and from Transcriptome Analysis of Cats
The variable domains of antigen receptors are very diverse and assembled in a modular system from a number of V-, D-, and J-region genes. Here we describe additional variants of V- and J-region genes of the feline T-cell receptor Îł (TRG) as well as the corresponding RSSs retrieved from Trace Archive of feline genomic sequences. Additionally, an unusually recombined TRGV-domain containing a partial inverted repeat of the included J-region and a short interspersed element of the CAN-SINE family located within the feline T-cell receptor Îł locus are also described
Desarrollo larvario de Dagetichthys marginatus (Familia: Soleidae) a partir de puesta inducida por hormonas en condiciones de cultivo artificiales
Dagetichthys marginatus (formerly Synaptura marginata) larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys, which is represented by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL) and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown.Las larvas de Dagetichthys marginatus (anteriormente Synaptura marginata) se cultivaron en el laboratorio a partir de adultos capturados en el medio natural como parte de un proyecto de investigaciĂłn en la zona templada de Sudáfrica. En este trabajo se presenta la descripciĂłn de las larvas de esta especie. Este trabajo tambiĂ©n representa la primera descripciĂłn del Dagetichthys, representado por cinco especies, tres de las cuales se encuentran en el Oeste del OcĂ©ano ĂŤndico. El desarrollo larvario de D. marginatus es el tĂpico de la familia Soleidae. Las larvas de Dagetichthys marginatus están fuertemente pigmentadas con cuatro caracterĂsticos bloques de melanĂłforos en la aleta primordial. Estas larvas se distinguen fácilmente de otras larvas de soleidos comĂşnmente encontradas en la zona templada de Sudáfrica en base a su gran longitud en el estadio de flexiĂłn (5-7.06 mm BL) y a su cuerpo fuertemente pigmentado. Las larvas en estado de postflexiĂłn obtenidas en el presente cultivo mostraron similares contajes que los adultos capturados en el medio natural. A pesar de la comĂşn apariciĂłn, en aguas someras, de adultos maduros de esta especie frente a la zona templada de Sudáfrica, las larvas estuvieron ausentes en las muestras de ictioplanton recolectadas en dicha zona. Hasta el momento, la estrategia de puesta de esta especie es desconocida.
Nucleon mass and pion loops: Renormalization
Using Dyson--Schwinger equations, the nucleon propagator is analyzed
nonperturbatively in a field--theoretical model for the pion--nucleon
interaction. Infinities are circumvented by using pion--nucleon form factors
which define the physical scale. It is shown that the correct, finite,
on--shell nucleon renormalization is important for the value of the mass--shift
and the propagator. For physically acceptable forms of the pion--nucleon form
factor the rainbow approximation together with renormalization is inconsistent.
Going beyond the rainbow approximation, the full pion--nucleon vertex is
modelled by its bare part plus a one--loop correction including an effective
. It is found that a consistent value for the nucleon mass--shift can
be obtained as a consequence of a subtle interplay between wave function and
vertex renormalization. Furthermore, the bare and renormalized pion--nucleon
coupling constant are approximately equal, consistent with results from the
Cloudy Bag Model.Comment: 14 pages, 6 figure
Writing in Water
Writing is an ancient communication technique dating back at least 30,000
years. While even sophisticated contemporary writing techniques hinge on solid
surfaces for engraving or the deposition of ink, writing within a liquid medium
requires a fundamentally different approach. We here demonstrate writing of
lines, letters and complex patterns in water by assembling lines of colloidal
particles. Exploiting gravity, we roll an ion-exchange bead (pen) across a
layer of sedimented colloidal particles (ink). The pen evokes a hydrodynamic
flow collecting ink-particles into a durable, high-contrast line along its
trajectory. Deliberate substrate-tilting sequences facilitate pen-steering and
thus to draw and write. We complement our experiments with a minimal model that
quantitatively predicts the observed parameter dependence for writing in fluids
and highlights the generic character of writing by line-assembly. Overall, our
approach opens a versatile route for writing, drawing and patterning fluids,
even at the micro-scale.Comment: Article 23 p, 5 figs, 53 refs, Supl. Info with 13 fig
Computational Advantages of Deep Prototype-Based Learning
International audienceWe present a deep prototype-based learning architecture which achieves a performance that is competitive to a conventional, shallow prototype-based model but at a fraction of the computational cost, especially w.r.t. memory requirements. As prototype-based classification and regression methods are typically plagued by the exploding number of prototypes necessary to solve complex problems, this is an important step towards efficient prototype-based classification and regression. We demonstrate these claims by benchmarking our deep prototype-based model on the well-known MNIST dataset
Silent ischemia: Evaluation by exercise and redistribution tomographic thallium-201 myocardial imaging
AbstractTo compare the amount of myocardium jeopardized during silent ischemia and painful ischemia, 112 consecutive patients undergoing coronary arteriography with ischemia demonstrated by exercise and redistribution tomographic thallium-201 myocardial imaging (SPECT) were divided into two groups: 84 patients without anginal pain (silent ischemia) and 28 with pain (painful ischemia). The SPECT apical, mid and basal ventricular levels of the short-axis view and the apical portion of the long-axis view were divided into 20 segments.The results were 1) 7.4 ± 4.7 ischemic segments in silent ischemia and 7.6 ± 3.7 in painful ischemia (p = NS) with 4.7 ± 3.6 segments in silent ischemia undergoing total redistribution compared with 5.4 ± 3.4 in painful ischemia (p = NS); 2) no difference in the incidence of single, double or triple vessel disease between silent and painful ischemic groups; 3) similar anatomic distribution of ischemic segments between the two groups; 4) more positive exercise electrocardiographic (ECG) changes in painful ischemia (70%) than in silent ischemia (32%) (p < 0.001) with equal amounts of ischemia associated with positive and negative exercise ECG findings.Conclusions: 1) Patients with silent and painful ischemia during exercise have similar amounts of ischemic myocardium demonstrated by tomographic thallium-201 imaging and similar extent of angiographically documented coronary artery disease despite the absence of pain and the lower incidence of positive exercise ECG findings in silent ischemia. 2) Positive and negative exercise ECG findings were associated with similar amounts of ischemic myocardium
Towards incremental deep learning: multi-level change detection in a hierarchical recognition architecture
International audienceWe present a trainable hierarchical architecture capable of detecting newness (or outliers) at all hierarchical levels. This contribution paves the way for deep neural architectures that are able to learn in an incremental fashion, for which the ability to detect newness is an indispensable prerequisite. We verify the ability to detect newness by conducting experiments on the MNIST database, where we introduce either localized changes, by adding noise to a small patch of the input, or global changes, by changing the global arrangement of local patterns which is not detectable at the local level
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