398 research outputs found
Malicious Prosecution Counterclaims Now Allowable in the Principal ActionâImplicit Abandonement of the Doctrine of Strict LimitationâWash. Rev. Code § 4.24.350 (Supp. 1977)
With the enactment of R.C.W. § 4.24.350,however, the Washington State Legislature has made the malicious plaintiff an endangered species in this state. The statute eliminates two major common law roadblocksâone procedural, the other substantiveâto successful assertion of an action for malicious prosecution of an ordinary civil suit. Unfortunately, because the new law is so intimidatingly expansive in its apparent scope, potential plaintiffs with arguably valid claims may also be deterred from seeking legal redress
Soft Resummation of Quark Anomalous Dimensions and Coefficient Functions in MS-bar Factorization
The asymptotic behaviour at large N of the MS-bar quark anomalous dimensions
is derived to all orders assuming only MS-bar factorization and standard
results for the exponentiation of soft logarithms in the quark initiated bare
cross sections for deep inelastic scattering and Drell-Yan. The result is then
used to write the MS-bar quark coefficient functions in a form in which all
terms of are resummed.Comment: 12 page
USP15 targets ALK3/BMPR1A for deubiquitylation to enhance bone morphogenetic protein signalling
Protein kinase ALK3/BMPR1A mediates bone morphogenetic protein (BMP) signalling through phosphorylation and activation of SMADs 1/5/8. SMAD6, a transcriptional target of BMP, negatively regulates the BMP pathway by recruiting E3 ubiquitin ligases and targeting ALK3 for ubiquitin-mediated degradation. Here, we identify a deubiquitylating enzyme USP15 as an interactor of SMAD6 and ALK3. We show that USP15 enhances BMP-induced phosphorylation of SMAD1 by interacting with and deubiquitylating ALK3. RNAi-mediated depletion of USP15 increases ALK3 K48-linked polyubiquitylation, and reduces both BMP-induced SMAD1 phosphorylation and transcription of BMP target genes. We also show that loss of USP15 expression from mouse myoblast cells inhibits BMP-induced osteoblast differentiation. Furthermore, USP15 modulates BMP-induced phosphorylation of SMAD1 and transcription during Xenopus embryogenesis
Characterizing Multi-planet Systems with Classical Secular Theory
Classical secular theory can be a powerful tool to describe the qualitative
character of multi-planet systems and offer insight into their histories. The
eigenmodes of the secular behavior, rather than current orbital elements, can
help identify tidal effects, early planet-planet scattering, and dynamical
coupling among the planets, for systems in which mean-motion resonances do not
play a role. Although tidal damping can result in aligned major axes after all
but one eigenmode have damped away, such alignment may simply be fortuitous. An
example of this is 55 Cancri (orbital solution of Fischer et al., 2008) where
multiple eigenmodes remain undamped. Various solutions for 55 Cancri are
compared, showing differing dynamical groupings, with implications for the
coupling of eccentricities and for the partitioning of damping among the
planets. Solutions for orbits that include expectations of past tidal evolution
with observational data, must take into account which eigenmodes should be
damped, rather than expecting particular eccentricities to be near zero.
Classical secular theory is only accurate for low eccentricity values, but
comparison with other results suggests that it can yield useful qualitative
descriptions of behavior even for moderately large eccentricity values, and may
have advantages for revealing underlying physical processes and, as large
numbers of new systems are discovered, for triage to identify where more
comprehensive dynamical studies should have priority.Comment: Published in Celestial Mechanics and Dynamical Astronomy, 25 pages,
10 figure
High-Resolution Chandra X-Ray Imaging And Spectroscopy Of The Sigma Orionis Cluster
We present results of a 90 ks Chandra X-ray observation of the young sigma Orionis cluster ( age similar to 3 Myr) obtained with the HETGS. We use the high-resolution grating spectrum and moderate-resolution CCD spectrum of the massive central star sigma Ori AB (O9.5 V + B0.5 V) to test wind shock theories of X-ray emission and also analyze the high spatial resolution zero-order ACIS-S image of the central cluster region. Chandra detected 42 X-ray sources on the primary CCD (ACIS-S3). All but five have near-IR or optical counterparts and about one-fourth are variable. Notable high-mass stellar detections are sigma Ori AB, the magnetic B star sigma Ori E, and the B5 V binary HD 37525. Most of the other detections have properties consistent with lower mass K- or M-type stars. We present the first X-ray spectrum of the unusual infrared source IRS 1, located approximate to 3 \u27\u27 north of sigma Ori AB. Its X-ray properties and elongated mid-IR morphology suggest that it is an embedded low-mass T Tauri star whose disk/envelope is being photoevaporated by sigma Ori AB. We focus on the radiative wind shock interpretation of the soft luminous X-ray emission from sigma Ori AB, but also consider possible alternatives including magnetically confined wind shocks and colliding wind shocks. Its emission lines show no significant asymmetries or centroid shifts and are moderately broadened to HWHM approximate to 264 km s(-1), or one-fourth the terminal wind speed. Forbidden lines in He-like ions are formally undetected, implying strong UV suppression. The Mg XI triplet forms in the wind acceleration zone within one stellar radius above the surface. These X-ray properties are consistent in several respects with the predictions of radiative wind shock theory for an optically thin wind, but explaining the narrow line widths presents a challenge to the theory
Perceived responder legitimacy and group identification predict cooperation and compliance in a mass decontamination field exercise
Emergency respondersâ failure to communicate effectively during decontamination following a chemical or biological incident has been associated with increased public anxiety and reduced public compliance. In this study we applied the social identity approach to evaluating a field exercise that involved mass decontamination. Questionnaires were collected from 115 volunteers, who participated in the exercise as simulated casualties. Volunteersâ perceptions of effective responder communication predicted increased self-reported compliance with decontamination, mediated by perceived responder legitimacy and identification with other group members. Developing effective communication strategies using a social psychology perspective could improve the way in which incidents are managed
Perturbatively Stable Resummed Small x Evolution Kernels
We present a small x resummation for the GLAP anomalous dimension and its
corresponding dual BFKL kernel, which includes all the available perturbative
information and nonperturbative constraints. Specifically, it includes all the
information coming from next-to-leading order GLAP anomalous dimensions and
BFKL kernels, from the constraints of momentum conservation, from
renormalization-group improvement of the running coupling and from gluon
interchange symmetry. The ensuing evolution kernel has a uniformly stable
perturbative expansion. It is very close to the unresummed NLO GLAP kernel in
most of the HERA kinematic region, the small x BFKL behaviour being softened by
momentum conservation and the running of the coupling. Next-to-leading
corrections are small thanks to the constraint of gluon interchange symmetry.
This result subsumes all previous resummations in that it combines optimally
all the information contained in them.Comment: 44 pages, 12 figures, plain TeX with harvmac. Final version, to be
published in Nucl. Phys. B. Discussion of integrated vs. unintegrated pdfs
added, see eqns. 5.5-5.7, 6.26-6.29. Figures 6-12 update
Small x Resummation with Quarks: Deep-Inelastic Scattering
We extend our previous results on small-x resummation in the pure Yang--Mills
theory to full QCD with nf quark flavours, with a resummed two-by-two matrix of
resummed quark and gluon splitting functions. We also construct the
corresponding deep-inelastic coefficient functions, and show how these can be
combined with parton densities to give fully resummed deep-inelastic structure
functions F_2 and F_L at the next-to-leading logarithmic level. We discuss how
this resummation can be performed in different factorization schemes, including
the commonly used MSbar scheme. We study the importance of the resummation
effects by comparison with fixed-order perturbative results, and we discuss the
corresponding renormalization and factorization scale variation uncertainties.
We find that for x below 0.01 the resummation effects are comparable in size to
the fixed order NNLO corrections, but differ in shape. We finally discuss the
phenomenological impact of the small-x resummation, specifically in the
extraction of parton distribution from present day experiments and their
extrapolation to the kinematics relevant for future colliders such as the LHCComment: 45 pages, 16 figures, plain TeX with harvma
A very brief description of LOFAR - the Low Frequency Array
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for
the frequency range 30-240 MHz. The telescope is realized as a phased aperture
array without any moving parts. Digital beam forming allows the telescope to
point to any part of the sky within a second. Transient buffering makes
retrospective imaging of explosive short-term events possible. The scientific
focus of LOFAR will initially be on four key science projects (KSPs): 1)
detection of the formation of the very first stars and galaxies in the universe
during the so-called epoch of reionization by measuring the power spectrum of
the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ~5' scale; 2)
low-frequency surveys of the sky with of order expected new sources; 3)
all-sky monitoring and detection of transient radio sources such as gamma-ray
bursts, x-ray binaries, and exo-planets (Farrell et al. 2004); and 4) radio
detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003)
allowing for the first time access to particles beyond 10^21 eV (Scholten et
al. 2006). Apart from the KSPs open access for smaller projects is also
planned. Here we give a brief description of the telescope.Comment: 2 pages, IAU GA 2006, Highlights of Astronomy, Volume 14, K.A. van
der Hucht, e
BFKL at Next-to-Next-to-Leading Order
We determine an approximate expression for the O(alpha_s^3) contribution
chi_2 to the kernel of the BFKL equation, which includes all collinear and
anticollinear singular contributions. This is derived using recent results on
the relation between the GLAP and BFKL kernels (including running-coupling
effects to all orders) and on small-x factorization schemes. We present the
result in various schemes, relevant both for applications to the BFKL equation
and to small-x evolution of parton distributions.Comment: 34 pages, 6 figures, TeX with harvmac. Various small typos corrects,
in particular first term in eq D.3. Final version to be published in Nucl.
Phys.
- âŠ