1,090 research outputs found
A Lyman-alpha blob in the GOODS South field: evidence for cold accretion onto a dark matter halo
We report on the discovery of a z = 3.16 Lyman-alpha emitting blob in the
GOODS South field. The blob has a total Ly-alpha luminosity of ~ 10^(43) erg
s^(-1) and a diameter larger than 60 kpc. The available multi-wavelength data
in the GOODS field consists of 13 bands from X-rays (Chandra) to infrared
(Spitzer). Unlike other discovered Ly-alpha blobs, this blob shows no obvious
continuum counter-part in any of the broad-bands. In particular, no optical
counter-parts are found in the deep HST/ACS imaging available. For previously
published blobs, AGN (Active Galactic Nuclei) or 'superwind' models have been
found to provide the best match with the data. We here argue that the most
probable origin of the extended Ly-alpha emission from the blob in the GOODS
South field is cold accretion onto a dark matter halo.Comment: 4 pages, 2 tables, 2 figures, Accepted to A&A Letters, minor changes
to tex
Social Conformity in Autism
Humans are extremely susceptible to social influence. Here, we examine whether this susceptibility is altered in autism, a condition characterized by social difficulties. Autistic participants (N=22) and neurotypical controls (N=22) completed a memory test of previously seen words and were then exposed to answers supposedly given by four other individuals. Autistic individuals and controls were as likely to alter their judgements to align with inaccurate responses of group members. These changes reflected both temporary judgement changes (public conformity) and long-lasting memory changes (private conformity). Both groups were more susceptible to answers believed to be from other humans than from computer algorithms. Our results suggest that autistic individuals and controls are equally susceptible to social influence when reporting their memories
Electrical conduction of ion tracks in tetrahedral amorphous carbon: temperature, field and doping dependence and comparison with matrix data
This paper gives an extended overview of the electrical properties of ion tracks in hydrogen-free tetrahedral amorphous carbon (ta-C) with a sp(3) bond fraction of about 80%. The films were grown by mass selected ion beam deposition of 100 eV C-12(+) ions. The ion tracks are generated by irradiation of ta-C films with uranium ions of 1 GeV kinetic energy. Along the ion path a conversion from diamondlike (sp(3)) carbon to graphite-like (sp(2)) carbon takes place. Topography and current measurements of individual ion tracks were performed by atomic force microscopy at ambient temperature. The temperature dependence of the electric conductivity was studied between 15 and 390 K by means of 0.28 mm(2) large contact pads averaging over about 10 7 tracks. For each sample and at each temperature the conductivity as a function of the applied electrical field (non-ohmic behaviour) was measured separately and the data were extrapolated to field zero. In this way, the zero-field conductivity was determined independent from the field dependence. In spite of large differences in the absolute values, the temperature dependence of the zero-field conductivities is found to be very similar in shape for all samples. The conductivities follow a T-1/4 law up to temperatures slightly below room temperature. At higher temperatures a transport mechanism based on over-barrier hopping dominates with an activation energy of about 220 meV for tracks and 260 meV for the ta-C matrix. The field dependence measurements show that the deviation of the I-V characteristics from ohmic behaviour decreases with increasing zero-field conductivity. We also tested Cu-doped ta-C samples and found that they conduct significantly better than pure ta-C. However, the doping also increases the zero-field conductivity resulting in a weaker contrast between the track and matrix. The data are interpreted within the so-called 'barrier model' where the electrons are assumed to move fairly freely in well-conducting sp(2) regions but encounter barriers in track sections consisting of more sp(3)-like bonds
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TREatment of ATopic eczema (TREAT) Registry Taskforce: consensus on how and when to measure the core dataset for atopic eczema treatment research registries.
BackgroundComparative, real-life and long-term evidence on the effectiveness and safety of phototherapy and systemic therapy in moderate-to-severe atopic eczema (AE) is limited. Such data must come from well-designed prospective patient registries. Standardization of data collection is needed for direct comparisons and data pooling.ObjectivesTo reach a consensus on how and when to measure the previously defined domain items of the TREatment of ATopic eczema (TREAT) Registry Taskforce core dataset for research registries for paediatric and adult patients with AE.MethodsProposals for the measurement instruments were based on recommendations of the Harmonising Outcome Measures for Eczema (HOME) initiative, the existing AE database of TREATgermany, systematic reviews of the literature and expert opinions. The proposals were discussed at three face-to-face consensus meetings, one teleconference and via e-mail. The frequency of follow-up visits was determined by an expert survey.ResultsA total of 16 experts from seven countries participated in the 'how to measure' consensus process and 12 external experts were consulted. A consensus was reached for all domain items on how they should be measured by assigning measurement instruments. A minimum follow-up frequency of initially 4 weeks after commencing treatment, then every 3 months while on treatment and every 6 months while off treatment was defined.ConclusionsThis core dataset for national AE research registries will aid in the comparability and pooling of data across centres and country borders, and enables international collaboration to assess the long-term effectiveness and safety of phototherapy and systemic therapy used in patients with AE. What's already known about this topic? Comparable, real-life and long-term data on the effectiveness and safety of phototherapy and systemic therapy in patients with atopic eczema (AE) are needed. There is a high diversity of outcomes and instruments used in AE research, which require harmonization to enhance comparability and allow data pooling. What does this study add? Our taskforce has reached international consensus on how and when to measure core domain items for national AE research registries. This core dataset is now available for use by researchers worldwide and will aid in the collection of unified data. What are the clinical implications of this work? The data collected through this core dataset will help to gain better insights into the long-term effectiveness and safety of phototherapy and systemic therapy in AE and will provide important information for clinical practice. Standardization of such data collection at the national level will also allow direct data comparisons and pooling across country borders (e.g. in the analysis of treatment-related adverse events that require large patient numbers)
Symmetric qubits from cavity states
Two-mode cavities can be prepared in quantum states which represent symmetric
multi-qubit states. However, the qubits are impossible to address individually
and as such cannot be independently measured or otherwise manipulated. We
propose two related schemes to coherently transfer the qubits which the cavity
state represents onto individual atoms, so that the qubits can then be
processed individually. In particular, our scheme can be combined with the
quantum cloning scheme of Simon and coworkers [C. Simon et al, PRL 84, 2993
(2000)] to allow the optimal clones which their scheme produces to be spatially
separated and individually utilized.Comment: 8 pages, 4 figures, minor typographical errors correcte
Charge Segregation, Cluster Spin-Glass and Superconductivity in La1.94Sr0.06CuO4
A 63Cu and 139La NMR/NQR study of superconducting (Tc=7 K) La1.94Sr0.06CuO4
single crystal is reported. Coexistence of spin-glass and superconducting
phases is found below ~5 K from 139La NMR relaxation. 63Cu and 139La NMR
spectra show that, upon cooling, CuO2 planes progressively separate into two
magnetic phases, one of them having enhanced antiferromagnetic correlations.
These results establish the AF-cluster nature of the spin-glass. We discuss how
this phase can be related to the microsegregation of mobile holes and to the
possible pinning of charge-stripes.Comment: 4 pages. Modified manuscript with clarification
Universal Continuous Variable Quantum Computation in the Micromaser
We present universal continuous variable quantum computation (CVQC) in the
micromaser. With a brief history as motivation we present the background theory
and define universal CVQC. We then show how to generate a set of operations in
the micromaser which can be used to achieve universal CVQC. It then follows
that the micromaser is a potential architecture for CVQC but our proof is
easily adaptable to other potential physical systems.Comment: 12 pages, 4 figures, accepted for a presentation at the 9th
International Conference on Unconventional Computation (UC10) and LNCS
proceedings
Quantum description of light pulse scattering on a single atom in waveguides
We present a time dependent quantum calculation of the scattering of a
few-photon pulse on a single atom. The photon wave packet is assumed to
propagate in a transversely strongly confined geometry, which ensures strong
atom-light coupling and allows a quasi 1D treatment. The amplitude and phase of
the transmitted, reflected and transversely scattered part of the wave packet
strongly depend on the pulse length (bandwidth) and energy. For a transverse
mode size of the order of , we find nonlinear behavior for a few
photons already, or even for a single photon. In a second step we study the
collision of two such wave packets at the atomic site and find striking
differences between Fock state and coherent state wave packets of the same
photon number.Comment: to appear in Phys. Rev.
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