8,134 research outputs found
Use of a Granulocyte Immunofluorescence Assay Designed for Humans for Detection of Antineutrophil Cytoplasmic Antibodies in Dogs with Chronic Enteropathies
Perinuclear antineutrophil cytoplasmic antibodies (pANCA) previously have been shown to be serum markers in dogs with chronic enteropathies, with dogs that have food‐responsive disease (FRD) having higher frequencies of seropositivity than dogs with steroid‐responsive disease (SRD). The indirect immunofluorescence (IIF) assay used in previous publications is time‐consuming to perform, with low interobserver agreement. Forty‐four dogs with FRD, 20 dogs with SRD, 20 control dogs, and 38 soft‐coated wheaten terrier (SCWT) or SCWT‐cross dogs
Spontaneous emergence of spatial patterns ina a predator-prey model
We present studies for an individual based model of three interacting
populations whose individuals are mobile in a 2D-lattice. We focus on the
pattern formation in the spatial distributions of the populations. Also
relevant is the relationship between pattern formation and features of the
populations' time series. Our model displays travelling waves solutions,
clustering and uniform distributions, all related to the parameters values. We
also observed that the regeneration rate, the parameter associated to the
primary level of trophic chain, the plants, regulated the presence of
predators, as well as the type of spatial configuration.Comment: 17 pages and 15 figure
Diffuse Galactic Gamma Rays from Shock-Accelerated Cosmic Rays
A shock-accelerated particle flux \propto p^-s, where p is the particle
momentum, follows from simple theoretical considerations of cosmic-ray
acceleration at nonrelativistic shocks followed by rigidity-dependent escape
into the Galactic halo. A flux of shock-accelerated cosmic-ray protons with s ~
2.8 provides an adequate fit to the Fermi-LAT gamma-ray emission spectra of
high-latitude and molecular cloud gas when uncertainties in nuclear production
models are considered. A break in the spectrum of cosmic-ray protons claimed by
Neronov, Semikoz, & Taylor (PRL, 108, 051105, 2012) when fitting the gamma-ray
spectra of high-latitude molecular clouds is a consequence of using a
cosmic-ray proton flux described by a power law in kinetic energy.Comment: Version to correspond to published letter in PRL; corrected Fig.
The RFOFO Ionization Cooling Ring for Muons
Practical ionization cooling rings could lead to lower cost or improved
performance in neutrino factory or muon collider designs. The ring modeled here
uses realistic three-dimensional fields. The performance of the ring compares
favorably with the linear cooling channel used in the second US Neutrino
Factory Study. The normalized 6D emittance of an ideal ring is decreased by a
factor of approximately 240, compared with a factor of only 15 for the linear
channel. We also examine such \textit{real-world} effects as windows on the
absorbers and rf cavities and leaving empty lattice cells for injection and
extraction. For realistic conditions the ring decreases the normalized 6D
emittance by a factor of 49.Comment: 27 pages, 18 figures and 5 tables. Submitted to Phys. Rev. ST-A
Dissipation in Poynting-flux Dominated Flows: the Sigma-Problem of the Crab Pulsar Wind
Flows in which energy is transported predominantly as Poynting flux are
thought to occur in pulsars, gamma-ray bursts and relativistic jets from
compact objects. The fluctuating component of the magnetic field in such a flow
can in principle be dissipated by magnetic reconnection, and used to accelerate
the flow. We investigate how rapidly this transition can take place, by
implementing into a global MHD model, that uses a thermodynamic description of
the plasma, explicit, physically motivated prescriptions for the dissipation
rate: a lower limit on this rate is given by limiting the maximum drift speed
of the current carriers to that of light, an upper limit follows from demanding
that the dissipation zone expand only subsonically in the comoving frame and a
further prescription is obtained by assuming that the expansion speed is
limited by the growth rate of the relativistic tearing mode. In each case,
solutions are presented which give the Lorentz factor of a spherical wind
containing a transverse, oscillating magnetic field component as a function of
radius. In the case of the Crab pulsar, we find that the Poynting flux can be
dissipated before the wind reaches the inner edge of the Nebula if the pulsar
emits electron positron pairs at a rate >1.E40 per second, thus providing a
possible solution to the sigma-problem.Comment: Accepted for publication in Ap
Aerodynamic characteristics of a large scale lift fan transport model with podded fans forward and lift cruise fans mounted above the wing
The aerodynamic characteristics of a large scale V/STOL transport model powered by tip-turbine driven lift fans were investigated. The model had four fans; the forward fans were mounted in pods forward of the wing at midsemispan. The aft fans were placed in cruise nacelles behind and above the wing. A cascade of variable camber exit louvers was placed behind each of the lift-cruise fans to turn the fan flow in the lift direction for hover and transition to wing supported flight. The wing of the model was mounted above the fuselage, had an aspect ratio of 5.8, sweepback of 35 deg at the quarter chord line and a taper ratio of 0.3. Various configurations of the model were tested to explore the transition speed range. Fan performance, turning effectiveness of the variable camber exit louvers, longitudinal and lateral-directional characteristics with fan operation in crossflow are presented
Sliding mode control of quantum systems
This paper proposes a new robust control method for quantum systems with
uncertainties involving sliding mode control (SMC). Sliding mode control is a
widely used approach in classical control theory and industrial applications.
We show that SMC is also a useful method for robust control of quantum systems.
In this paper, we define two specific classes of sliding modes (i.e.,
eigenstates and state subspaces) and propose two novel methods combining
unitary control and periodic projective measurements for the design of quantum
sliding mode control systems. Two examples including a two-level system and a
three-level system are presented to demonstrate the proposed SMC method. One of
main features of the proposed method is that the designed control laws can
guarantee desired control performance in the presence of uncertainties in the
system Hamiltonian. This sliding mode control approach provides a useful
control theoretic tool for robust quantum information processing with
uncertainties.Comment: 18 pages, 4 figure
Functional consequences of seven novel mutations in the CYP11B1 Gene: four mutations associated with nonclassic and three mutations causing classic 11 -Hydroxylase Deficiency
Context: Steroid 11β-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency.
Objective: The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations.
Methods: We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein.
Results: All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11β-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively.
Conclusion: Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling i
A Herschel study of the properties of starless cores in the Polaris Flare dark cloud region using PACS and SPIRE
The Polaris Flare cloud region contains a great deal of extended emission. It
is at high declination and high Galactic latitude. It was previously seen
strongly in IRAS Cirrus emission at 100 microns. We have detected it with both
PACS and SPIRE on Herschel. We see filamentary and low-level structure. We
identify the five densest cores within this structure. We present the results
of a temperature, mass and density analysis of these cores. We compare their
observed masses to their virial masses, and see that in all cases the observed
masses lie close to the lower end of the range of estimated virial masses.
Therefore, we cannot say whether they are gravitationally bound prestellar
cores. Nevertheless, these are the best candidates to be potentialprestellar
cores in the Polaris cloud region.Comment: 5 pages, 2 figures, accepted by A&
The theory of pulsar winds and nebulae
We review current theoretical ideas on pulsar winds and their surrounding
nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the
striped wind, together with models of magnetic dissipation are discussed. It is
shown that the observational signature of this dissipation is likely to be
point-like, rather than extended, and that pulsed emission may be produced. The
possible pulse shapes and polarisation properties are described. Particle
acceleration at the termination shock of the wind is discussed, and it is
argued that two distinct mechanisms must be operating, with the first-order
Fermi mechanism producing the high-energy electrons (above 1 TeV) and either
magnetic annihilation or resonant absorption of ion cyclotron waves responsible
for the 100 MeV to 1 TeV electrons. Finally, MHD models of the morphology of
the nebula are discussed and compared with observation.Comment: 33 pages, to appear in Springer Lecture Notes on "Neutron stars and
pulsars, 40 years after the discovery", ed W.Becke
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