Quantum phases of a qutrit

We consider various approaches to treat the phases of a qutrit. Although it is possible to represent qutrits in a convenient geometrical manner by resorting to a generalization of the Poincare sphere, we argue that the appropriate way of dealing with this problem is through phase operators associated with the algebra su(3). The rather unusual properties of these phases are caused by the small dimension of the system and are explored in detail. We also examine the positive operator-valued measures that can describe the qutrit phase properties.Comment: 6 page

Porous medium equation with nonlocal pressure

We provide a rather complete description of the results obtained so far on the nonlinear diffusion equation $u_t=\nabla\cdot (u^{m-1}\nabla (-\Delta)^{-s}u)$, which describes a flow through a porous medium driven by a nonlocal pressure. We consider constant parameters $m>1$ and $0<s<1$, we assume that the solutions are non-negative, and the problem is posed in the whole space. We present a theory of existence of solutions, results on uniqueness, and relation to other models. As new results of this paper, we prove the existence of self-similar solutions in the range when $N=1$ and $m>2$, and the asymptotic behavior of solutions when $N=1$. The cases $m = 1$ and $m = 2$ were rather well known.Comment: 24 pages, 2 figure

Active Galactic Nuclei with Candidate Intermediate-Mass Black Holes

We present an initial sample of 19 intermediate-mass black hole candidates in active galactic nuclei culled from the First Data Release of the Sloan Digital Sky Survey. Using the linewidth-luminosity-mass scaling relation established for broad-line active nuclei, we estimate black hole masses in the range of 8 x 10^4 - 10^6 solar masses, a regime in which only two objects are currently known. The absolute magnitudes are faint for active galactic nuclei, ranging from M_g of -15 to -18 mag, while the bolometric luminosities are all close to the Eddington limit. The entire sample formally satisfies the linewidth criterion for so-called narrow-line Seyfert 1 galaxies; however, they display a wider range of FeII and [OIII] (5007) line strengths than is typically observed in this class of objects. Although the available imaging data are of insufficient quality to ascertain the detailed morphologies of the host galaxies, it is likely that the majority of the hosts are relatively late-type systems. The host galaxies have estimated g-band luminosities ~ 1 mag fainter than M* for the general galaxy population at z of 0.1. Beyond simply extending the known mass range of central black holes in galactic nuclei, these objects provide unique observational constraints on the progenitors of supermassive black holes. They are also expected to contribute significantly to the integrated signal for future gravitational wave experiments.Comment: ApJ Accepted, 13 pages, 9 figures, uses emulateapj.cl

Ac magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a microSQUID sensor

We report the controlled integration, via Dip Pen Nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 Bohr magnetons) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 100, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.Comment: 4 pages 3 figure

Muon spin rotation and neutron scattering study of the non-centrosymmetric tetragonal compound CeAuAl3

We have investigated the non-centrosymmetric tetragonal heavy-fermion compound CeAuAl3 using muon spin rotation (muSR), neutron diffraction (ND) and inelastic neutron scattering (INS) measurements. We have also revisited the magnetic, transport and thermal properties. The magnetic susceptibility reveals an antiferromagnetic transition at 1.1 K with a possibility of another magnetic transition near 0.18 K. The heat capacity shows a sharp lambda-type anomaly at 1.1 K in zero-filed, which broadens and moves to higher temperature in applied magnetic field. Our zero-field muSR and ND measurements confirm the existence of a long-range magnetic ground state below 1.2 K. Further the ND study reveals an incommensurate magnetic ordering with a magnetic propagation vector k = (0, 0, 0.52) and a spiral structure of Ce moments coupled ferromagnetically within the ab-plane. Our INS study reveals the presence of two well-defined crystal electric field (CEF) excitations at 5.1 meV and 24.6 meV in the paramagnetic phase of CeAuAl3 which can be explained on the basis of the CEF theory. Furthermore, low energy quasi-elastic excitations show a Gaussian line shape below 30 K compared to a Lorentzian line shape above 30 K, indicating a slowdown of spin fluctuation below 30 K. We have estimated a Kondo temperature of TK=3.5 K from the quasi-elastic linewidth, which is in good agreement with that estimated from the heat capacity. This study also indicates the absence of any CEF-phonon coupling unlike that observed in isostructural CeCuAl3. The CEF parameters, energy level scheme and their wave functions obtained from the analysis of INS data explain satisfactorily the single crystal susceptibility in the presence of two-ion anisotropic exchange interaction in CeAuAl3.Comment: 28 pages and 17 figure

Statistical Properties of Radio Emission from the Palomar Seyfert Galaxies

We have carried out an analysis of the radio and optical properties of a statistical sample of 45 Seyfert galaxies from the Palomar spectroscopic survey of nearby galaxies. We find that the space density of bright galaxies (-22 mag <= M_{B_T} <= -18 mag) showing Seyfert activity is (1.25 +/- 0.38) X 10^{-3} Mpc^{-3}, considerably higher than found in other Seyfert samples. Host galaxy types, radio spectra, and radio source sizes are uncorrelated with Seyfert type, as predicted by the unified schemes for active galaxies. Approximately half of the detected galaxies have flat or inverted radio spectra, more than expected based on previous samples. Surprisingly, Seyfert 1 galaxies are found to have somewhat stronger radio sources than Seyfert 2 galaxies at 6 and 20 cm, particularly among the galaxies with the weakest nuclear activity. We suggest that this difference can be accommodated in the unified schemes if a minimum level of Seyfert activity is required for a radio source to emerge from the vicinity of the active nucleus. Below this level, Seyfert radio sources might be suppressed by free-free absorption associated with the nuclear torus or a compact narrow-line region, thus accounting for both the weakness of the radio emission and the preponderance of flat spectra. Alternatively, the flat spectra and weak radio sources might indicate that the weak active nuclei are fed by advection-dominated accretion disks.Comment: 18 pages using emulateapj5, 13 embedded figures, accepted by Ap

Discovery of Radio Outbursts in the Active Nucleus of M81

The low-luminosity active galactic nucleus of M81 has been monitored at centimeter wavelengths since early 1993 as a by-product of radio programs to study the radio emission from Supernova 1993J. The extensive data sets reveal that the nucleus experienced several radio outbursts during the monitoring period. At 2 and 3.6 cm, the main outburst occurred roughly in the beginning of 1993 September and lasted for approximately three months; at longer wavelengths, the maximum flux density decreases, and the onset of the burst is delayed. These characteristics qualitatively resemble the standard model for adiabatically expanding radio sources, although certain discrepancies between the observations and the theoretical predictions suggest that the model is too simplistic. In addition to the large-amplitude, prolonged variations, we also detected milder changes in the flux density at 3.6 cm and possibly at 6 cm on short (less than 1 day) timescales. We discuss a possible association between the radio activity and an optical flare observed during the period that the nucleus was monitored at radio wavelengths.Comment: To appear in The Astronomical Journal. Latex, 18 pages including embedded figures and table

Fórmulas de inmunonutrición enteral en la cirugía del cáncer de cabeza y cuello: Una revisión sitemática

Introduction: Significant malnutrition exists in a high percentage of patients with head and neck cancer. Malnutrition is associated with defects in immune function that may impair the host response to malignancy. Malnutrition and immunosupression make patients highly susceptible to postoperative infections and complications. Objectives: Some studies of patients receiving immunonutrition in the perioperative period in head and neck cancer have shown beneficial effects on clinical outcome and inmune status. The authors carried out a systematic review of randomised control trials to determine whether perioperative immunonutrition has a role in the treatment of head and neck cancer. Methods: 14 trials of polymeric nutritional supplementation with immunonutrition were identified. Two studies compared two types of immunonutrition. Results: A reduction in the length of postoperative hospital stay was seen in some trials, but the reason for this reduction is not clear. Some studides showed statistical differences with less complications in arginineenhanced group and also showed a significant decrease of fistula complications in patients treated with a high arginine dose enhanced formula, if compared with a medium dose of arginine. Conclussion: Those planning future studies face challenges. A suitable powered clinical trial is required before firm recommendations can be made on the use of immunonutrition in head and neck cancer patients postoperativelyIntroducción: Un alto porcentaje de pacientes con cáncer de cabeza y cuello presentan un importante grado de malnutrición. Esta malnutrición está asociada defectos de la función inmune. Tanto la malnutrición como la inmunosupresión hacen a estos pacientes susceptibles de padecer complicaciones infecciosas en el postoperatorio. Objetivos: Algunos trabajos de pacientes que han recibido inmunonutrición en el postoperatorio de cirugía por cáncer de cabeza y cuello han mostrado un efecto beneficioso en la evolución clínica y el estado inmune. Los autores han llevado a cabo una revisión sistemática de los ensayos clínicos realizados hasta la fecha, para determinar el papel que tiene la inmunonutrición enteral postoperatoria en el tratamiento del cáncer de cabeza y cuello. Métodos: Se identificaron 14 trabajos en los que se habían utilizado fórmulas de inmunonutrición. Dos trabajos compararon dos tipos de inmunonutrición. Resultados: En algunos trabajos se observó una disminución en los días de estancia hospitalaria, aunque la razón para ello no está clara. Algunos estudios mostraron diferencias significativas con menos complicaciones en los grupos que recibieron nutriciones enriquecidas, presentando una disminución significativa en el número de fístulas en pacientes tratados con nutriciones con altas dosis de arginina, si se compara con una nutrición con una dosis media de arginina. Conclusión: Los futuros trabajos presentan retos. Es necesario un ensayo clínico extenso, para poder realizar recomendaciones firmes sobre el uso de la inmunonutrición en el postoperatorio de pacientes intervenidos de cáncer de cabeza y cuell

Epifisiólisis femoral proxima: revisión de 44 casos

Se revisan 44 niños con 47 epifisiólisis femorales proximales. Veintitrés desplazamientos fueron leves, 18 moderados y 6 severos. Todas las epifisiólisis excepto 1 se trataron quirúrgicamente. En 10 casos se fijó profilácticamente la cadera contralateral. Existió penetración articular por el implante en 17 (30%) de las 56 caderas fijadas. El seguimiento medio ha sido de 56 meses (rango: 3 a 148 meses). Los resultados, según criterios clínicos y radiográficos, han sido excelentes o buenos en el 91% de los deslizamientos leves, el 77% de los moderados y el 33% de los severos. Las complicaciones fueron 2 casos de condrólisis, ambos asociados a penetración articular. En 2 (6%) de los pacientes donde no se realización profiláctica se produjo deslizamiento contralateral. En nuestro estudio los resultados se correlacionan con la cuantía del deslizamiento. No recomendamos la fijación profiláctica contraletal.We review 44 children with 47 slipped capital femoral epiphysis. There were 23 mild slips, 18 moderate, and 6 severe. Operative treatment was performed in all but one of the slips. In 10 cases prophylactic pinning of the contralateral hip was performed. Penetration of the joint by the implant was present in 17 (30%) of the 56 fixed hips. The average follow-up was 56 months (range: 3 to 178 months). The results, according to clinical and rocntgenographic parameters were excellent or good in 91% of mild slips, 77% of moderate and 33% of severe. As complications there were two cases of chondrolysis, both associated with joint penetration. In 2 (6%) patients where prophylactic pinning was not performed, contralateral hip slipping developed. In our study, results correlate with slip severity. We do not recommend prophylactic contralateral pinning

Design of the Front End Electronics for the Infrared Camera of JEM-EUSO, and manufacturing and verification of the prototype model

The Japanese Experiment Module (JEM) Extreme Universe Space Observatory (EUSO) will be launched and attached to the Japanese module of the International Space Station (ISS). Its aim is to observe UV photon tracks produced by ultra-high energy cosmic rays developing in the atmosphere and producing extensive air showers. The key element of the instrument is a very wide-field, very fast, large-lense telescope that can detect extreme energy particles with energy above $10^{19}$ eV. The Atmospheric Monitoring System (AMS), comprising, among others, the Infrared Camera (IRCAM), which is the Spanish contribution, plays a fundamental role in the understanding of the atmospheric conditions in the Field of View (FoV) of the telescope. It is used to detect the temperature of clouds and to obtain the cloud coverage and cloud top altitude during the observation period of the JEM-EUSO main instrument. SENER is responsible for the preliminary design of the Front End Electronics (FEE) of the Infrared Camera, based on an uncooled microbolometer, and the manufacturing and verification of the prototype model. This paper describes the flight design drivers and key factors to achieve the target features, namely, detector biasing with electrical noise better than $100 \mu$V from $1$ Hz to $10$ MHz, temperature control of the microbolometer, from $10^{\circ}$C to $40^{\circ}$C with stability better than $10$ mK over $4.8$ hours, low noise high bandwidth amplifier adaptation of the microbolometer output to differential input before analog to digital conversion, housekeeping generation, microbolometer control, and image accumulation for noise reduction