4,003 research outputs found
Tumores mamarios en felinos domésticos. Epidemiología, criterios de diagnóstico y enfoque terapéutico
On the Observables Describing a Quantum Reference Frame
A reference frame F is described by the element g of the Poincare' group P
which connects F with a given fixed frame F_0. If F is a quantum frame, defined
by a physical object following the laws of quantum physics, the parameters of g
have to be considered as quantum observables. However, these observables are
not compatible and some of them, namely the coordinates of the origin of F,
cannot be represented by self-adjoint operators. Both these difficulties can be
overcome by considering a positive-operator-valued measure (POVM) on P,
covariant with respect to the left translations of the group, namely a
covariance system. We develop a construction procedure for this kind of
mathematical structure. The formalism is also used to discuss the quantum
observables measured with respect to a quantum reference frame.Comment: 23 pages, no figure
Correction to: FASTA/Q data compressors for MapReduce-Hadoop genomics: space and time savings made easy
Following publication of the original article [1], the authors identified that the affiliations of Giuseppe Cattaneo and Raffaele Giancarlo were interchanged. The correct affiliations are given below.
The correct affiliation of Giuseppe Cattaneo is:
2Dipartimento di Informatica, Università di Salerno, Fisciano, Italy.
The correct affiliation of Raffaele Giancarlo is:
3Dipartimento di Matematica ed Informatica, Università di Palermo, Palermo, Italy.
The original article [1] has been corrected
Covariant localizations in the torus and the phase observables
We describe all the localization observables of a quantum particle in a
one-dimensional box in terms of sequences of unit vectors in a Hilbert space.
An alternative representation in terms of positive semidefinite complex
matrices is furnished and the commutative localizations are singled out. As a
consequence, we also get a vector sequence characterization of the covariant
phase observables.Comment: 16 pages, no figure, Latex2
Estudio retrospectivo de los principales sistemas orgánicos afectados en 435 caninos traumatizados (1996-2007)
In the present study analyzed the major organ systems affected in trauma patients. Resulting in the musculoskeletal system that corresponds to the main system affected a total of 435 canines. Se realizo un estudio retrospectivo de 435 atenciones en caninos que sufrieron algún tipo de trauma, analizándose los principales sistemas orgánicos afectados. Se encontró que los principales daños afectaron al sistema músculo- esquelético y en segundo lugar al sistema tegumentario. Es considerablemente menor el porcentaje de presentación de otros sistemas afectados.
Cell culture–based production of defective interfering influenza A virus particles in perfusion mode using an alternating tangential flow filtration system
Respiratory diseases including influenza A virus (IAV) infections represent a major threat to human health. While the development of a vaccine requires a lot of time, a fast countermeasure could be the use of defective interfering particles (DIPs) for antiviral therapy. IAV DIPs are usually characterized by a large internal deletion in one viral RNA segment. Consequentially, DIPs can only propagate in presence of infectious standard viruses (STVs), compensating the missing gene function. Here, they interfere with and suppress the STV replication and might act “universally” against many IAV subtypes. We recently reported a production system for purely clonal DIPs utilizing genetically modified cells. In the present study, we established an automated perfusion process for production of a DIP, called DI244, using an alternating tangential flow filtration (ATF) system for cell retention. Viable cell concentrations and DIP titers more than 10 times higher than for a previously reported batch cultivation were observed. Furthermore, we investigated a novel tubular cell retention device for its potential for continuous virus harvesting into the permeate. Very comparable performances to typically used hollow fiber membranes were found during the cell growth phase. During the virus replication phase, the tubular membrane, in contrast to the hollow fiber membrane, allowed 100% of the produced virus particles to pass through. To our knowledge, this is the first time a continuous virus harvest was shown for a membrane-based perfusion process. Overall, the process established offers interesting possibilities for advanced process integration strategies for next-generation virus particle and virus vector manufacturing. Key points • An automated perfusion process for production of IAV DIPs was established. • DIP titers of 7.40E + 9 plaque forming units per mL were reached. • A novel tubular cell retention device enabled continuous virus harvesting. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00253-021-11561-y
Memory Effects in Turbulent Dynamo: Generation and Propagation of Large Scale Magnetic Field
We are concerned with large scale magnetic field dynamo generation and
propagation of magnetic fronts in turbulent electrically conducting fluids. An
effective equation for the large scale magnetic field is developed here that
takes into account the finite correlation times of the turbulent flow. This
equation involves the memory integrals corresponding to the dynamo source term
describing the alpha-effect and turbulent transport of magnetic field. We find
that the memory effects can drastically change the dynamo growth rate, in
particular, non-local turbulent transport might increase the growth rate
several times compared to the conventional gradient transport expression.
Moreover, the integral turbulent transport term leads to a large decrease of
the speed of magnetic front propagation.Comment: 13 pages, 2 figure
Numerical simulations of current generation and dynamo excitation in a mechanically-forced, turbulent flow
The role of turbulence in current generation and self-excitation of magnetic
fields has been studied in the geometry of a mechanically driven, spherical
dynamo experiment, using a three dimensional numerical computation. A simple
impeller model drives a flow which can generate a growing magnetic field,
depending upon the magnetic Reynolds number, Rm, and the fluid Reynolds number.
When the flow is laminar, the dynamo transition is governed by a simple
threshold in Rm, above which a growing magnetic eigenmode is observed. The
eigenmode is primarily a dipole field tranverse to axis of symmetry of the
flow. In saturation the Lorentz force slows the flow such that the magnetic
eigenmode becomes marginally stable. For turbulent flow, the dynamo eigenmode
is suppressed. The mechanism of suppression is due to a combination of a time
varying large-scale field and the presence of fluctuation driven currents which
effectively enhance the magnetic diffusivity. For higher Rm a dynamo reappears,
however the structure of the magnetic field is often different from the laminar
dynamo; it is dominated by a dipolar magnetic field which is aligned with the
axis of symmetry of the mean-flow, apparently generated by fluctuation-driven
currents. The fluctuation-driven currents have been studied by applying a weak
magnetic field to laminar and turbulent flows. The magnetic fields generated by
the fluctuations are significant: a dipole moment aligned with the symmetry
axis of the mean-flow is generated similar to those observed in the experiment,
and both toroidal and poloidal flux expulsion are observed.Comment: 14 pages, 14 figure
Restriction of measles virus gene expression in acute and subacute encephalitis in Lewis rats
No abstract availabl
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