Marginal resection and adjuvant strontium plesiotherapy in the management of feline eyelid malignant peripheral nerve sheath tumours: two cases

Case series summary Two cats with a marginally resected eyelid malignant peripheral nerve sheath tumour were treated with adjuvant strontium plesiotherapy a few weeks after surgery. The dose applied in both cases was 200 Gy to the surface, in five fractions, on a Monday–Wednesday–Friday basis. The treatment aimed to achieve a clinical margin of approximately 1 cm around the surgical scar and multiple application fields were required to cover such an area. Local recurrence was not seen in either case after 1330 and 645 days, respectively. Relevance and novel information The majority of periocular malignant peripheral nerve sheath tumours reported in the literature recur after surgery. In the two cases described in this report the combination of surgery and adjuvant plesiotherapy has been able to provide good local control with minimal toxicity. This multimodal approach could be considered as an alternative to aggressive surgery such as enucleation or exenteration

Exact corrections for finite-time drift and diffusion coefficients

Real data are constrained to finite sampling rates, which calls for a suitable mathematical description of the corrections to the finite-time estimations of the dynamic equations. Often in the literature, lower order discrete time approximations of the modeling diffusion processes are considered. On the other hand, there is a lack of simple estimating procedures based on higher order approximations. For standard diffusion models, that include additive and multiplicative noise components, we obtain the exact corrections to the empirical finite-time drift and diffusion coefficients, based on It\^o-Taylor expansions. These results allow to reconstruct the real hidden coefficients from the empirical estimates. We also derive higher-order finite-time expressions for the third and fourth conditional moments, that furnish extra theoretical checks for that class of diffusive models. The theoretical predictions are compared with the numerical outcomes of some representative artificial time-series.Comment: 18 pages, 5 figure

Strong coupling corrections in quantum thermodynamics

Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and always vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic situation of non-Markovian quantum Brownian motion.Comment: 20 pages, 3 figures, version two is substantially revised and contains new result

Work and entropy production in generalised Gibbs ensembles

Recent years have seen an enormously revived interest in the study of thermodynamic notions in the quantum regime. This applies both to the study of notions of work extraction in thermal machines in the quantum regime, as well as to questions of equilibration and thermalisation of interacting quantum many-body systems as such. In this work we bring together these two lines of research by studying work extraction in a closed system that undergoes a sequence of quenches and equilibration steps concomitant with free evolutions. In this way, we incorporate an important insight from the study of the dynamics of quantum many body systems: the evolution of closed systems is expected to be well described, for relevant observables and most times, by a suitable equilibrium state. We will consider three kinds of equilibration, namely to (i) the time averaged state, (ii) the Gibbs ensemble and (iii) the generalised Gibbs ensemble (GGE), reflecting further constants of motion in integrable models. For each effective description, we investigate notions of entropy production, the validity of the minimal work principle and properties of optimal work extraction protocols. While we keep the discussion general, much room is dedicated to the discussion of paradigmatic non-interacting fermionic quantum many-body systems, for which we identify significant differences with respect to the role of the minimal work principle. Our work not only has implications for experiments with cold atoms, but also can be viewed as suggesting a mindset for quantum thermodynamics where the role of the external heat baths is instead played by the system itself, with its internal degrees of freedom bringing coarse-grained observables to equilibrium.Comment: 22 pages, 4 figures, improvements in presentatio

Recent progress in the truncated Lanczos method : application to hole-doped spin ladders

The truncated Lanczos method using a variational scheme based on Hilbert space reduction as well as a local basis change is re-examined. The energy is extrapolated as a power law function of the Hamiltonian variance. This systematic extrapolation procedure is tested quantitatively on the two-leg t-J ladder with two holes. For this purpose, we have carried out calculations of the spin gap and of the pair dispersion up to size 2x15.Comment: 5 pages, 4 included eps figures, submitted to Phys. Rev. B; revised versio

The complex structure of HH 110 as revealed from Integral Field Spectroscopy

HH 110 is a rather peculiar Herbig-Haro object in Orion that originates due to the deflection of another jet (HH 270) by a dense molecular clump, instead of being directly ejected from a young stellar object. Here we present new results on the kinematics and physical conditions of HH 110 based on Integral Field Spectroscopy. The 3D spectral data cover the whole outflow extent (~4.5 arcmin, ~0.6 pc at a distance of 460 pc) in the spectral range 6500-7000 \AA. We built emission-line intensity maps of H$\alpha$, [NII] and [SII] and of their radial velocity channels. Furthermore, we analysed the spatial distribution of the excitation and electron density from [NII]/H$\alpha$, [SII]/H$\alpha$, and [SII] 6716/6731 integrated line-ratio maps, as well as their behaviour as a function of velocity, from line-ratio channel maps. Our results fully reproduce the morphology and kinematics obtained from previous imaging and long-slit data. In addition, the IFS data revealed, for the first time, the complex spatial distribution of the physical conditions (excitation and density) in the whole jet, and their behaviour as a function of the kinematics. The results here derived give further support to the more recent model simulations that involve deflection of a pulsed jet propagating in an inhomogeneous ambient medium. The IFS data give richer information than that provided by current model simulations or laboratory jet experiments. Hence, they could provide valuable clues to constrain the space parameters in future theoretical works.Comment: 12 pages, 15 figures Accepted in MNRA

3-D Kinematics of the HH 110 jet

We present new results on the kinematics of the jet HH 110. New proper motion measurements have been calculated from [SII] CCD images obtained with a time baseline of nearly fifteen years. HH 110 proper motions show a strong asymmetry with respect to the outflow axis, with a general trend of pointing towards the west of the axis direction. Spatial velocities have been obtained by combining the proper motions and radial velocities from Fabry-Perot data. Velocities decrease by a factor ~3 over a distance of ~10$^{18}$ cm, much shorter than the distances expected for the braking caused by the jet/environment interaction. Our results show evidence of an anomalously strong interaction between the outflow and the surrounding environment, and are compatible with the scenario in which HH 110 emerges from a deflection in a jet/cloud collision.Comment: (1)Universitat de Barcelona; (2)UNAM; (3)UPC; (4)University of Hawaii; (5)Southern Astrophysical Research Telescope. 9 pages; 7 Figures Accepted by A&

Thermodynamic Properties of the Spin-1/2 Antiferromagnetic ladder Cu2(C2H12N2)2Cl4 under Magnetic Field

Specific heat ($C_V$) measurements in the spin-1/2 Cu$_2$(C$_2$H$_{12}$N$_2$)$_2$Cl$_4$ system under a magnetic field up to $H=8.25 T$ are reported and compared to the results of numerical calculations based on the 2-leg antiferromagnetic Heisenberg ladder. While the temperature dependences of both the susceptibility and the low field specific heat are accurately reproduced by this model, deviations are observed below the critical field $H_{C1}$ at which the spin gap closes. In this Quantum High Field phase, the contribution of the low-energy quantum fluctuations are stronger than in the Heisenberg ladder model. We argue that this enhancement can be attributed to dynamical lattice fluctuations. Finally, we show that such a Heisenberg ladder, for $H>H_{C1}$, is unstable, when coupled to the 3D lattice, against a lattice distortion. These results provide an alternative explanation for the observed low temperature ($T_C\sim 0.5K$ -- $0.8K$) phase (previously interpreted as a 3D magnetic ordering) as a new type of incommensurate gapped state.Comment: Minor changes, list of authors complete