2,975 research outputs found
Construction of Infrared Finite Observables in N=4 Super Yang-Mills Theory
In this paper we give all the details of the calculation that we presented in
our previous paper ArXiv:0908.0387 where the infrared structure of the MHV
gluon amplitudes in the planar limit for super Yang-Mills theory
was considered in the next-to-leading order of perturbation theory. Explicit
cancellation of the infrared divergencies in properly defined inclusive
cross-sections is demonstrated first in a toy model example of "conformal QED"
and then in the real SYM theory. We give the full-length details
both for the calculation of the real emission and for the diagrams with
splitting in initial and final states. The finite parts for some inclusive
differential cross-sections are presented in an analytical form. In general,
contrary to the virtual corrections, they do not reveal any simple structure.
An example of the finite part containing just the log functions is presented.
The dependence of inclusive cross-section on the external scale related to the
definition of asymptotic states is discussed.Comment: 49 pages, LATEX, 6 eps figures; Minor changes, Refs adde
Storage of correlated patterns in a perceptron
We calculate the storage capacity of a perceptron for correlated gaussian
patterns. We find that the storage capacity can be less than 2 if
similar patterns are mapped onto different outputs and vice versa. As long as
the patterns are in general position we obtain, in contrast to previous works,
that in agreement with Cover's theorem. Numerical simulations
confirm the results.Comment: 9 pages LaTeX ioplppt style, figures included using eps
Evolution of genes and repeats in the Nimrod superfamily
The recently identified Nimrod superfamily is characterized by the presence of a special type of EGF repeat, the NIM repeat, located right after a typical CCXGY/W amino acid motif. On the basis of structural features, nimrod genes can be divided into three types. The proteins encoded by Draper-type genes have an EMI domain at the N-terminal part and only one copy of the NIM motif, followed by a variable number of EGF-like repeats. The products of Nimrod B-type and Nimrod C-type genes (including the eater gene) have different kinds of N-terminal domains, and lack EGF-like repeats but contain a variable number of NIM repeats. Draper and Nimrod C-type (but not Nimrod B-type) proteins carry a transmembrane domain. Several members of the superfamily were claimed to function as receptors in phagocytosis and/or binding of bacteria, which indicates an important role in the cellular immunity and the elimination of apoptotic cells. In this paper, the evolution of the Nimrod superfamily is studied with various methods on the level of genes and repeats. A hypothesis is presented in which the NIM repeat, along with the EMI domain, emerged by structural reorganizations at the end of an EGF-like repeat chain, suggesting a mechanism for the formation of novel types of repeats. The analyses revealed diverse evolutionary patterns in the sequences containing multiple NIM repeats. Although in the Nimrod B and Nimrod C proteins show characteristics of independent evolution, many internal NIM repeats in Eater sequences seem to have undergone concerted evolution. An analysis of the nimrod genes has been performed using phylogenetic and other methods and an evolutionary scenario of the origin and diversification of the Nimrod superfamily is proposed. Our study presents an intriguing example how the evolution of multigene families may contribute to the complexity of the innate immune response
dc readout experiment at the Caltech 40m prototype interferometer
The Laser Interferometer Gravitational Wave Observatory (LIGO) operates a 40m prototype interferometer on the Caltech campus. The primary mission of the prototype is to serve as an experimental testbed for upgrades to the LIGO interferometers and for gaining experience with advanced interferometric techniques, including detuned resonant sideband extraction (i.e. signal recycling) and dc readout (optical homodyne detection). The former technique will be employed in Advanced LIGO, and the latter in both Enhanced and Advanced LIGO. Using dc readout for gravitational wave signal extraction has several technical advantages, including reduced laser and oscillator noise couplings as well as reduced shot noise, when compared to the traditional rf readout technique (optical heterodyne detection) currently in use in large-scale ground-based interferometric gravitational wave detectors. The Caltech 40m laboratory is currently prototyping a dc readout system for a fully suspended interferometric gravitational wave detector. The system includes an optical filter cavity at the interferometer's output port, and the associated controls and optics to ensure that the filter cavity is optimally coupled to the interferometer. We present the results of measurements to characterize noise couplings in rf and dc readout using this system
Response of Cloud Condensation Nuclei (> 50 nm) to changes in ion-nucleation
In experiments where ultraviolet light produces aerosols from trace amounts
of ozone, sulphur dioxide, and water vapour, the number of additional small
particles produced by ionization by gamma sources all grow up to diameters
larger than 50 nm, appropriate for cloud condensation nuclei. This result
contradicts both ion-free control experiments and also theoretical models that
predict a decline in the response of larger particles due to an insufficiency
of condensable gases (which leads to slower growth) and to larger losses by
coagulation between the particles. This unpredicted experimental finding points
to a process not included in current theoretical models, possibly an
ion-induced formation of sulphuric acid in small clusters.Comment: 4 pages, 3 figure
HAE international home therapy consensus document
Hereditary angioedema (C1 inhibitor deficiency, HAE) is associated with intermittent swellings which are disabling and may be fatal. Effective treatments are available and these are most useful when given early in the course of the swelling. The requirement to attend a medical facility for parenteral treatment results in delays. Home therapy offers the possibility of earlier treatment and better symptom control, enabling patients to live more healthy, productive lives. This paper examines the evidence for patient-controlled home treatment of acute attacks ('self or assisted administration') and suggests a framework for patients and physicians interested in participating in home or self-administration programmes. It represents the opinion of the authors who have a wide range of expert experience in the management of HAE
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