735 research outputs found
Making Sense of Corporate Tour-Guide Bloggers’ Networking Behavior: A Social Network Perspective
Drawing on studies of social networks and technology sensemaking, this study examines tour guide bloggers’ perceptions of their corporate blogs and how their perceptions and interpretations lead to different types of relationships in their blog networks. We conduct a qualitative case study of a major Taiwanese travel agency. Our findings suggest that corporate bloggers as actors make different senses on blogging and these senses lead them to establish different levels of closeness to their alters (other network actors). Providing social support and especially material support play significant roles in aggrandizing the transitivity, which help to attract more visitors to their blogs. However, the innovation and potential connections that may follow from the individualistic styles of some bloggers in addition to the hedonic emotional support to a travel blog should not be overlooked. Corporate bloggers should thus consider offering more incentives and should be given freedom to prosper in their grassroots use of technology
Magnetic field symmetry of pump currents of adiabatically driven mesoscopic structures
We examine the scattering properties of a slowly and periodically driven
mesoscopic sample using the Floquet function approach. One might expect that at
sufficiently low driving frequencies it is only the frozen scattering matrix
which is important. The frozen scattering matrix reflects the properties of the
sample at a given instant of time. Indeed many aspects of adiabatic scattering
can be described in terms of the frozen scattering matrix. However, we
demonstrate that the Floquet scattering matrix, to first order in the driving
frequency, is determined by an additional matrix which reflects the fact that
the scatterer is time-dependent. This low frequency irreducible part of the
Floquet matrix has symmetry properties with respect to time and/or a magnetic
field direction reversal opposite to that of the frozen scattering matrix. We
investigate the quantum rectification properties of a pump which additionally
is subject to an external dc voltage. We split the dc current flowing through
the pump into several parts with well defined properties with respect to a
magnetic field and/or an applied voltage inversion.Comment: 13 pages, 4 figure
Surface Structure of √3x√3R 30 Cl/Ni(111) Determined Using Low-temperature Angle-Resolved-Photoemission Extended Fine Structure
A surface structural study of the √3 × √3 R30° Cl/Ni(111) adsorbate system was made using low-temperature angle-resolved photoemission extended fine structure. The experiments were performed along two emission directions, [111] and [110], and at two temperatures, 120 and 300 K. The multiple-scattering spherical-wave analysis determined that the Cl atom adsorbs in the fcc threefold hollow site, 1.837(8) Å above the first nickel layer, with a Cl-Ni bond length of 2.332(6) Å, and an approximate 5% contraction between the first and the second nickel layers (the errors in parentheses are statistical standard deviations only)
Recommended from our members
How Bulk Sensitive is Hard X-ray Photoelectron Spectroscopy: Accounting for the Cathode-Electrolyte Interface when Addressing Oxygen Redox.
Sensitivity to the "bulk" oxygen core orbital makes hard X-ray photoelectron spectroscopy (HAXPES) an appealing technique for studying oxygen redox candidates. Various studies have reported an additional O 1s peak (530-531 eV) at high voltages, which has been considered a direct signature of the bulk oxygen redox process. Here, we find the emergence of a 530.4 eV O 1s HAXPES peak for three model cathodes-Li2MnO3, Li-rich NMC, and NMC 442-that shows no clear link to oxygen redox. Instead, the 530.4 eV peak for these three systems is attributed to transition metal reduction and electrolyte decomposition in the near-surface region. Claims of oxygen redox relying on photoelectron spectroscopy must explicitly account for the surface sensitivity of this technique and the extent of the cathode degradation layer
Probing the Protostellar Envelope around L1157: the Dust and Gas Connection
We present observations of the Class 0 protostar L1157-mm using the Combined
Array for Research in Millimeter-wave Astronomy (CARMA) in 3 mm dust continuum
and N2H+ line emission. In the N2H+ line, we detect a large-scale envelope
extended over a linear size of ~20,000AU flattened in the direction
perpendicular to the outflow. This N2H+ feature coincides with the outer
envelope seen in the 8 micron extinction by Looney et al. Meanwhile, the dust
continuum traces the compact, nearly spherical structure of the inner envelope,
where N2H+ becomes depleted. This highly flattened N2H+ envelope also shows
dynamical signatures consistent with gravitational infall in the inner region,
but a slow, solid-body rotation at large scales. This flattened structure is
not a rotationally supported circumstellar disk; instead, it resembles a
prestellar core both morphologically and kinematically, representing the early
phase of a Class 0 system. In this paper, we construct a simple model to
interpret both the dust continuum and N2H+ emission and suggest a possible
dynamical scenario for the overall properties of the envelope.Comment: Accepted for publication by the ApJ, 34 pages, 10 figures and 2
table
Externally Fed Accretion onto Protostars
The asymmetric molecular emission lines from dense cores reveal slow, inward
motion in the clouds' outer regions. This motion is present both before and
after the formation of a central star. Motivated by these observations, we
revisit the classic problem of steady, spherical accretion of gas onto a
gravitating point mass, but now include self-gravity of the gas and impose a
finite, subsonic velocity as the outer boundary condition. We find that the
accretion rate onto the protostar is lower than values obtained for isolated,
collapsing clouds, by a factor that is the Mach number of the outer flow.
Moreover, the region of infall surrounding the protostar spreads out more
slowly, at a speed close to the subsonic, incoming velocity. Our calculation,
while highly idealized, provides insight into two longstanding problems -- the
surprisingly low accretion luminosities of even the most deeply embedded
stellar sources, and the failure so far to detect spatially extended,
supersonic infall within their parent dense cores. Indeed, the observed
subsonic contraction in the outer regions of dense cores following star
formation appears to rule out a purely hydrodynamic origin for these clouds.Comment: accepted by MNRA
Model-based analysis of two-color arrays (MA2C)
A normalization method based on probe GC content for two-color tiling arrays and an algorithm for detecting peak regions are presented. They are available in a stand-alone Java program
VIPER: Visualization Pipeline for RNA-seq, a Snakemake workflow for efficient and complete RNA-seq analysis
BACKGROUND: RNA sequencing has become a ubiquitous technology used throughout life sciences as an effective method of measuring RNA abundance quantitatively in tissues and cells. The increase in use of RNA-seq technology has led to the continuous development of new tools for every step of analysis from alignment to downstream pathway analysis. However, effectively using these analysis tools in a scalable and reproducible way can be challenging, especially for non-experts.
RESULTS: Using the workflow management system Snakemake we have developed a user friendly, fast, efficient, and comprehensive pipeline for RNA-seq analysis. VIPER (Visualization Pipeline for RNA-seq analysis) is an analysis workflow that combines some of the most popular tools to take RNA-seq analysis from raw sequencing data, through alignment and quality control, into downstream differential expression and pathway analysis. VIPER has been created in a modular fashion to allow for the rapid incorporation of new tools to expand the capabilities. This capacity has already been exploited to include very recently developed tools that explore immune infiltrate and T-cell CDR (Complementarity-Determining Regions) reconstruction abilities. The pipeline has been conveniently packaged such that minimal computational skills are required to download and install the dozens of software packages that VIPER uses.
CONCLUSIONS: VIPER is a comprehensive solution that performs most standard RNA-seq analyses quickly and effectively with a built-in capacity for customization and expansion
Solution of the Nuclear Shell Model by Symmetry-Dictated Truncation
The dynamical symmetries of the Fermion Dynamical Symmetry Model are used as
a principle of truncation for the spherical shell model. Utilizing the usual
principle of energy-dictated truncation to select a valence space, and
symmetry-dictated truncation to select a collective subspace of that valence
space, we are able to reduce the full shell model space to one of manageable
dimensions with modern supercomputers, even for the heaviest nuclei. The
resulting shell model then consists of diagonalizing an effective Hamiltonian
within the restricted subspace. This theory is not confined to any symmetry
limits, and represents a full solution of the original shell model if the
appropriate effective interaction of the truncated space can be determined. As
a first step in constructing that interaction, we present an empirical
determination of its matrix elements for the collective subspace with no broken
pairs in a representative set of nuclei with . We demonstrate
that this effective interaction can be parameterized in terms of a few
quantities varying slowly with particle number, and is capable of describing a
broad range of low-energy observables for these nuclei. Finally we give a brief
discussion of extending these methods to include a single broken collective
pair.Comment: invited paper for J. Phys. G, 57 pages, Latex, 18 figures a macro are
available under request at [email protected]
Floquet states and persistent currents transitions in a mesoscopic ring
We consider the effect of an oscillating potential on the single-particle
spectrum and the time-averaged persistent current of a one-dimensional
phase-coherent mesoscopic ring with a magnetic flux. We show that in a ring
with an even number of spinless electrons the oscillating potential has a
strong effect on the persistent current when the excited side bands are close
to the eigen levels of a pure ring. Resonant enhancement of side bands of the
Floquet state generates a sign change of the persistent current.Comment: 2 figure
- …