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Z(SPA-1) is an engineered protein that binds to its parent, the three-helix-bundle Z domain of staphylococcal protein A. Uncomplexed Z(SPA-1) shows a reduced helix content and a melting behavior that is less cooperative, compared with the wild-type Z domain. Here we show that the difference in folding behavior between these two sequences can be partly understood in terms of an off-lattice model wi
We present a novel, versatile optoelectronic neural network architecture for implementing supervised learning algorithms in photorefractive materials. The system is based on spatial multiplexing rather than the more commonly used angular multiplexing of the interconnect gratings. This simple, single-crystal architecture implements a variety of multilayer supervised learning algorithms including me
We propose and investigate a unifying class of sparse random graph models, based on a hidden coloring of edge-vertex incidences, extending an existing approach, random graphs with a given degree distribution, in a way that admits a nontrivial correlation structure in the resulting graphs. The approach unifies a number of existing random graph ensembles within a common general formalism, and allows
We present an assay, based on optical DNA mapping in nanochannels that is capable of characterizing the plasmid content of bacterial isolates resistant to antibiotics in a fast an detailed way. In a single experiment we determine the number of different plasmids in each sample, their size, as well as a barcode that can be used for plasmid identification and tracing. In addition we demonstrate that
A novel artificial neural network approach to constraint satisfaction problems is presented. Based on information-theoretical considerations, it differs from a conventional mean-field approach in the form of the resulting free energy. The method, implemented as an annealing algorithm, is numerically explored on a testbed of K-SAT problems. The performance shows a dramatic improvement over that of
Designing amino acid sequences that are stable in a given target structure amounts to maximizing a conditional probability. A straightforward approach to accomplish this is a nested Monte Carlo where the conformation space is explored over and over again for different fixed sequences. In this paper we discuss an alternative Monte Carlo approach, multisequence design, where conformation and sequenc
När en utredare observerar en olycksplats är bevisen de kan hitta viktiga. Bevisen är det som gör att de kan återskapa hur olyckan hände och förstå vad som hände. Men om de inte förstår bevisen, eller använder dom för att återskapa olycksplatsen på fel sätt, kan svaret de får vara fel. Inom partikelfysik kolliderar vi atomkärnor med extrema energier för att se vilka hemligheter universum har. För The purpose of this thesis was to implement an alternative method to calculate the overlap function, which describe to what extent two protons overlap with each other spatially, into PYTHIA8 in order to determine how it affected the average number of multiparton interactions. The new overlap function is based on an explicit impact parameter picture, whereas PYTHIA8s overlap function uses an implic
Pythia version 6 represents a merger of the Pythia 5, Jetset 7 and SPythia programs, with many improvements. It can be used to generate high-energy-physics 'events', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions. The underlying physics
Recent advances in coarse-grained lattice and off-lattice protein models are reviewed. The sequence dependence of thermodynamical folding properties are investigated and evidence for non-randomness of the binary sequences of good folders are discussed. Similar patterns for non-randomness are found for real proteins. Dynamical parameter MC methods, such as the tempering and multisequence algorithms
Observations of the ultra-sharp-lined, chemically peculiar star chi Lupi taken by the Goddard High Resolution Spectrograph in echelle mode are presented. Thirty-six intervals of the spectral region between 1249 and 2688 Angstrom are covered with resolving powers in the range 75,000-93,000. Line identifications are provided, and the observed spectra are compared with synthetic spectra calculated us
We present a QCD-based model where rescattering between final state partons in deep inelastic scattering leads to events with large rapidity gaps and a leading proton. In the framework of this model the amplitude for multiple gluon exchanges is calculated in the eikonal approximation to all orders in perturbation theory. Both large and small invariant mass MX limits are considered. The model succe
Radial velocity observations from three instruments reveal the presence of a 4 M Jup planet candidate orbiting the K giant HD 76920. HD 76920b has an orbital eccentricity of 0.856 ±0.009, making it the most eccentric planet known to orbit an evolved star. There is no indication that HD 76920 has an unseen binary companion, suggesting a scattering event rather than Kozai oscillations as a probable
The solar neighbourhood contains disc stars that have recently crossed spiral arms in the Galaxy. We propose that boundaries in local velocity distributions separate stars that have recently crossed and been more strongly perturbed by a particular arm from those that haven't. Ridges in the stellar velocity distributions constructed from the second Gaia data release trace orbits that could have tou
NGC 2419 is one of the remotest star clusters in the Milky Way halo and its exact nature is yet unclear. While it has traits reminiscent of a globular cluster, its large radius and suggestions of an abundance spread have fueled the discussion about its origin in an extragalactic environment, possibly the remnant of the accretion of a dwarf galaxy. Here, we present first results from deep intermedi
We present stellar parameters, stellar ages, and detailed elemental abundances for Na, Mg, Al, Si, Ca, Ti, Cr, Fe, and Ni for 32 solar sibling candidates. Technique of chemical tagging gives us a high probability that four stars might be from the same open cluster. Only one candidate HIP 40317 which has solar metallicity and age could be a solar sibling. We performed simulations of the Sun's birth
Within the framework of a simple model of photophysical processes in the Weigelt blobs in the vicinity of the luminous blue variable (LBV) star eta Carinae, we explain the presence of the fluorescent < O I > 8446-angstrom and forbidden [O I] 6300-angstrom lines as well as the absence of the allowed O I 7774-angstrom line in spectra recorded with the Hubble Space Telescope (HST)/STIS instrument (Gu
