Comment on "On the uncertainty relations and squeezed states for the quantum mechanics on a circle"

It is shown by examples that the position uncertainty on a circle, proposed recently by Kowalski and Rembieli\'nski [J. Phys. A 35 (2002) 1405] is not consistent with the state localization. We argue that the relevant uncertainties and uncertainty relations (UR's) on a circle are that based on the Gram-Robertson matrix. Several of these generalized UR's are displayed and related criterions for squeezed states are discussed.Comment: 5 pages, LaTex2e, 3 figures.ep

Dark Energy in an Axion Model with Explicit Z(N) Symmetry Breaking

We point out that a well known axion model with an explicit Z(N) symmetry breaking term predicts both dark energy and cold dark matter. We estimate the parameters of this model which fit the observed densities of the dark components of the universe. We find that the parameters do not conflict with any observations.Comment: 5 pages, minor change

Listado anotado de Solanum L. (Solanaceae) en el Peru.

The genus Solanum is among the most species-rich genera both of the Peruvian flora and of the tropical Andes in general. The present revised checklist treats 276 species of Solanum L., of which 253 are native, while 23 are introduced and/or cultivated. A total of 74 Solanum species (29% of native species) are endemic to Peru. Additional 58 species occur only in small number of populations outside Peru, and these species are here labelled as near-endemics to highlight the role Peru playes in their future protection. Species diversity is observed to peak between 2500 – 3000 m elevation, but endemic species diversity is highest between 3000 – 3500 m elevation. Cajamarca has the highest number of endemic (29 spp.) and total species (130 spp.), even when considering the effect of area. Centers of endemic species diversity are observed in provinces of Cajamarca (Cajamarca), Huaraz and Carhuaz (Ancash), and Canta and Huarochirí (Lima). Secondary centres of endemism with high concentrations of both endemics and near-endemics are found in San Ignacio and Cutervo (Cajamarca), Santiago de Chuco (La Libertad), Oxapampa (Pasco), and Cusco (Cusco). Current diversity patterns are highly correlated with collection densities, and further collecting is needed across all areas, especially from Arequipa, Ayacucho, Puno, Ancash, Huánuco, Amazonas and Cajamarca, where high levels of species diversity and endemism are indicated but only a few collections of many species are known.Solanum L. es uno de los géneros que posee una alta riqueza de especies dentro de la flora peruana y dentro de los Andes tropicales en general. Presentamos una lista revisada de 276 especies de Solanum para el Perú, de estas 253 son nativas, mientras que 23 son introducidas y/o cultivadas. Un total de 74 especies de Solanum (29% de las especies nativas) son endémicas de Perú. Además 58 especies se encuentran solamente en pequeñas poblaciones fuera del Perú, y estas especies están designadas aquí como casi endémicas para destacar el rol importante del Perú en la futura protección de estas especies. El pico de diversidad de especies es observado entre 2500 – 3000 m de elevación, pero la diversidad de especies endémicas es más alta entre 3000 – 3500 m. Cajamarca tiene el más alto número de especies (130 spp.) y de especies endémicas (29 spp.), incluso si se considera el efecto del área. Centros de diversidad de especies endémicas se localizan en las provincias de Cajamarca (Cajamarca), Huaraz y Carhuaz (Ancash), Canta y Huarochirí (Lima). Centros de endemismos secundarios con una alta concentración tanto de especies endémicas y de casi endémicas se encuentran en San Ignacio y Cutervo (Cajamarca), Santiago de Chuco (La Libertad), Oxapampa (Pasco), y Cusco (Cusco): Los actuales patrones de diversidad están altamente correlacionados con la densidad de colecciones, por lo que es necesario una mayor colecta en todas las regiones, especialmente en Arequipa, Ayacucho, Puno, Ancash, Huánuco, Amazonas y Cajamarca, donde se indican altos niveles de diversidad y endemismo de especies, pero de las cuales existen pocas colecciones

Early in-flight detection of SO₂ via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes

Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO₂) or sulphuric acid (H₂SO₄) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO₂ receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. <br><br> Up to now, remote sensing of SO₂ via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO₂ in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO₂ in the flight direction and at &pm;40 mrad (2.3&deg;) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO₂ was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 10¹² molecules cm^&minus;3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds

Hidden Kondo Effect in a Correlated Electron Chain

We develop a general Bethe Ansatz formalism for diagonalizing an integrable model of a magnetic impurity of arbitrary spin coupled ferro- or antiferromagnetically to a chain of interacting electrons. The method is applied to an open chain, with the exact solution revealing a ``hidden'' Kondo effect driven by forward electron scattering off the impurity. We argue that the so-called ``operator reflection matrices'' proposed in recent Bethe Ansatz studies of related models emulate only forward electron-impurity scattering which may explain the absence of complete Kondo screening for certain values of the impurity-electron coupling in these models.Comment: 5 pages, RevTex; to appear in Phys. Rev. Let

Herschel-ATLAS: VISTA VIKING near-IR counterparts in the Phase 1 GAMA 9h data

We identify near-infrared Ks band counterparts to Herschel-ATLAS sub-mm sources, using a preliminary object catalogue from the VISTA VIKING survey. The sub-mm sources are selected from the H-ATLAS Phase 1 catalogue of the GAMA 9h field, which includes all objects detected at 250, 350 or 500 um with the SPIRE instrument. We apply and discuss a likelihood ratio (LR) method for VIKING candidates within a search radius of 10" of the 22,000 SPIRE sources with a 5 sigma detection at 250 um. We find that 11,294(51%) of the SPIRE sources have a best VIKING counterpart with a reliability $R\ge 0.8$, and the false identification rate of these is estimated to be 4.2%. We expect to miss ~5% of true VIKING counterparts. There is evidence from Z-J and J-Ks colours that the reliable counterparts to SPIRE galaxies are marginally redder than the field population. We obtain photometric redshifts for ~68% of all (non-stellar) VIKING candidates with a median redshift of 0.405. Comparing to the results of the optical identifications supplied with the Phase I catalogue, we find that the use of medium-deep near-infrared data improves the identification rate of reliable counterparts from 36% to 51%.Comment: 20 pages, 20 figures, 3 tables, accepted by MNRA

Gravitating discs around black holes

Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole--disc system by analytical solutions of stationary, axially symmetric Einstein's equations. Then, more detailed considerations are focused to middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring, however, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging and completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the environment around. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star--disc interactions, which can be recognised in observational properties, such as the relation between the central mass and stellar velocity dispersion.Comment: Accepted for publication in CQG; high-resolution figures will be available from http://www.iop.org/EJ/journal/CQ

Measuring Black Hole Spin using X-ray Reflection Spectroscopy

I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009

NIVEL DE CONOCIMIENTOS DEL DIABÉTICO SOBRE SU AUTO CUIDADO

INTRODUCTION The diabetes treatment is complex. Its results depend, to a great extent, on the level of comprehension, skill and motivation that the user face up to the therapeutic requirements. OBJETIVE To identify the knowledge level that the diabetic user has about his/her autocare. MATERIAL AND METHODS A descriptive survey was carried out in 94 diabetic inpatients in the services of Internal Medicine and Surgery of the General Regional Hospital No. 1 of Culiacán, Sinaloa. Diabetics of 20 years old and older with more of 72 hours of hospitalization in internal medicine and surgery were included in the survey. A questionnaire providing socio-demographic aspects such as age, gender, education, knowledge level of the diabetic user about his/her autocare dealing aspects like exercise, diet, feet care and pharmacological treatment was used. RESULTS More than half (56%) of the studied population is men, with an average age of 60 years old with a standard deviation of +- 12.36. The knowledge level about his/her autocare was insufficient in 79%. CONCLUSIONS The diabetic users have insufficient knowledge about their autocare. The aspects they know more about are the exercise and the diet, while they know little about the feet care and pharmacological treatment.INTRODUCCIÓN El tratamiento de la diabetes es complejo y sus resultados dependen, en gran medida del nivel de comprensión, destreza y motivación con que el usuario afronta las exigencias terapéuticas. OBJETIVO Identificar el nivel de conocimiento que el usuario diabético tiene sobre su autocuidado. MATERIAL Y MÉTODOS Se realizó una encuesta descriptiva a 94 diabéticos hospitalizados en los servicios de medicina interna y cirugía del Hospital General Regional No. 1 de Culiacán Sinaloa. Se incluyeron diabéticos de 20 y más años de edad, con más de 72 horas de hospitalización en el servicio. Se utilizó un cuestionario que contempló aspectos sociodemográficos como son edad, sexo, escolaridad, nivel de conocimiento del usuario diabético sobre su autocuidado, contemplando aspectos como ejercicio, alimentación, cuidado de los pies y tratamiento farmacológico. RESULTADO De la población estudiada se encontró que el 56% son del sexo masculino, con un promedio de 60 años de edad con una desviación estándar de + - 12.36. Nivel de conocimiento del diabético sobre su auto cuidado fue insuficiente en un 79 %. CONCLUSIONES Los usuarios diabéticos tienen conocimientos insuficientes sobre su autocuidado. Los aspectos sobre los que más conoce son el ejercicio y la alimentación, no así el cuidado de sus pies y lo relacionado al tratamiento farmacológico

Analysis of a Two-Class FCFS Queueing System with Interclass Correlation

This paper considers a discrete-time queueing system with one server and two classes of customers. All arriving customers are accommodated in one queue, and are served in a First-Come-First-Served order, regardless of their classes. The total numbers of arrivals during consecutive time slots are i.i.d. random variables with arbitrary distribution. The classes of consecutively arriving customers, however, are correlated in a Markovian way, i.e., the probability that a customer belongs to a class depends on the class of the previously arrived customer. Service-time distributions are assumed to be general but class-dependent. We use probability generating functions to study the system analytically. The major aim of the paper is to estimate the impact of the interclass correlation in the arrival stream on the queueing performance of the system, in terms of the (average) number of customers in the system and the (average) customer delay and customer waiting time