604 research outputs found
Visible spectroscopy of the new ESO Large Program on trans-Neptunian objects and Centaurs: final results
A second large programme (LP) for the physical studies of TNOs and Centaurs,
started at ESO Cerro Paranal on October 2006 to obtain high-quality data, has
recently been concluded. In this paper we present the spectra of these pristine
bodies obtained in the visible range during the last two semesters of the LP.
We investigate the spectral behaviour of the TNOs and Centaurs observed, and we
analyse the spectral slopes distribution of the full data set coming from this
LP and from the literature. We computed the spectral slope for each observed
object, and searched for possible weak absorption features. A statistical
analysis was performed on a total sample of 73 TNOs and Centaurs to look for
possible correlations between dynamical classes, orbital parameters, and
spectral gradient. We obtained new spectra for 28 bodies, 15 of which were
observed for the first time. All the new presented spectra are featureless,
including 2003 AZ84, for which a faint and broad absorption band possibly
attributed to hydrated silicates on its surface has been reported. The data
confirm a wide variety of spectral behaviours, with neutral--grey to very red
gradients. An analysis of the spectral slopes available from this LP and in the
literature for a total sample of 73 Centaurs and TNOs shows that there is a
lack of very red objects in the classical population. We present the results of
the statistical analysis of the spectral slope distribution versus orbital
parameters. In particular, we confirm a strong anticorrelation between spectral
slope and orbital inclination for the classical population. A strong
correlation is also found between the spectral slope and orbital eccentricity
for resonant TNOs, with objects having higher spectral slope values with
increasing eccentricity.Comment: 11 pages, 9 figure
Obtained and characterization of composite materials W-Cu for electrical contact
9 páginas, 5 figuras, 4 tablas.-- Nota técnica.[ES] En el Centro de Investigaciones Metalúrgicas (CIME), cubano, se fabrican por
pulvimetalurgia, calzos de material compuesto volframio-cobre, que se utilizan en los
contactos eléctricos de los paneles de control de las grúas pórtico que operan en el puerto
de Ciudad de La Habana. El material base que se utiliza contiene un 70 % en masa de polvo
de cobre electrolítico y polvo de volframio (30 %), que se obtiene por reducción del óxido
de volframio. Los polvos se someten a las etapas de mezclado, prensado y sinterización
obteniéndose un material compuesto con las fases metálicas formadas por partículas libres
de volframio ocluidas en una matriz de cobre, que no interaccionan entre sí. Este material
compuesto proporciona al calzo de ajuste las siguientes propiedades: alta temperatura de
fusión, alta electrotermoconductividad y resistencia a la corrosión, alta resistencia
mecánica y a la erosión eléctrica, baja soldabilidad y estabilidad durante su explotación. Sin
embargo, al no reaccionar las partículas de volframio con el cobre, el material compuesto
comenzará a fundir a la temperatura del cobre; por otro lado y, por la misma razón la
resistencia a la corrosión debe ser similar a la del cobre puro. Los calzos de ajuste se fijan a
los cuerpos de cobre de alta pureza mediante una soldadura de una aleación de plata, la cual
no afecta las buenas cualidades del cobre, como elasticidad, resistencia a la tracción,
conductividad térmica y eléctrica, así como resistencia a la corrosión.[EN] In the Cuban Metallurgical Research Center (CIME), are manufactured by powder
metallurgy, shims of adjustment of a W-Cu composite material, that are used in the
electrical contacts of the panels of control of the portico derricks that operate in the port
of Havana City. The base material used has a composition of 70 % in mass electrolytic
copper powder and wolfram powder of (30 %) that is obtained by reduction from the oxide
from wolfram. The powders are submitted to the stages of mixed, pressed and agglomeration
and is obtained a composite material with free particles of W occluded in a counterfoil of
Cu matrix, that do not interact and they provide the following properties: high melting
temperature, high electro and thermo conductivity and corrosion resistance, high
mechanical and electrical strengtheners, decrease weldability and stability during their
development. However, when not reacting the volframio particles with the copper, the
compound material will begin to fuse to the temperature of the copper, on the other hand
and for the same reason the resistance to the corrosion should be similar to that of the pure
copper. The shims of adjustment are fixed to the bodies of high purity copper welding with
a silver alloy, the one which provides the maximum qualities of the Cu, as elasticity,
breaking strength, thermal and electrical conductivities, as well corrosion resistance.Peer reviewe
The Edgeworth-Kuiper debris disk
(Abridged) The Edgeworth-Kuiper belt with its presumed dusty debris is a
natural reference for extrsolar debris disks. We employ a new algorithm to
eliminate the inclination and the distance selection effects in the known TNO
populations to derive expected parameters of the "true" EKB. Its estimated mass
is M_EKB=0.12 M_earth, which is by a factor of \sim 15 larger than the mass of
the EKB objects detected so far. About a half of the total EKB mass is in
classical and resonant objects and another half is in scattered ones. Treating
the debiased populations of EKB objects as dust parent bodies, we then
"generate" their dust disk with our collisional code. Apart from accurate
handling of collisions and direct radiation pressure, we include the
Poynting-Robertson (P-R) drag, which cannot be ignored for the EKB dust disk.
Outside the classical EKB, the radial profile of the optical depth
approximately follows tau \sim r^-2 which is roughly intermediate between the
slope predicted analytically for collision-dominated (r^-1.5) and
transport-dominated (r^-2.5) disks. The cross section-dominating grain size
still lies just above the blowout size (\sim 1...2 \microm), as it would
without the P-R transport. However, if the EKB were by one order of magnitude
less massive, the optical depth profile would fall off as tau \sim r^-3, and
the cross section-dominating grain size would shift from \sim 1...2\microm to
~100 \microm. These properties are seen if dust is assumed to be generated only
by known TNOs. If the solar system were observed from outside, the thermal
emission flux from the EKB dust would be about two orders of magnitude lower
than for solar-type stars with the brightest known infrared excesses observed
from the same distance. Herschel and other new-generation facilities should
reveal extrasolar debris disks nearly as tenuous as the EKB disk. The
Herschel/PACS instrument should be able to detect disks at a \sim 1...2M_EKB
level.Comment: 18 pages, 14 figures, accepted for publication in A&
Comparison of the Analytical and Clinical Performance of Five Tests for the Detection of Human Papillomavirus Genital Infection
HPV-based screening provides greater protection against cervical
cancer (CC) than cytology-based strategies. Currently, several
molecular diagnostic assays for the detection of human
papillomavirus (HPV) are available. In this study, we analyzed 5
different HPV testing and genotyping techniques (Hybrid Capture
2 [HC2; Qiagen, Hilden, Germany], AnyplexTMII HPV28 [Anyplex;
Seegene, Seoul, Korea], Linear Array [Roche, Branchburg, NJ,
USA], GP5+/6+ PCR-EIA-RH [Labo Bio-medical Products, Rijswijk,
The Netherlands] and CLART2 [Genomica, Madrid, Spain]) in 295
women referred to the hospital Colposcopy Clinic from 2007 to
2008 due to positive HPV test results or an abnormal Pap test.
DNA extraction for HPV genotyping was performed in cervical
sample specimens after Pap test and HPV detection by HC2. The
inclusion criteria were: (1) adequate cervical sampling with
sufficient material for the Pap test and HPV detection and
genotyping, and (2) colposcopically-directed biopsy and/or
endocervical curettage. HC2 showed the highest sensitivity for
high-grade squamous intraepithelial lesion and CC (HSIL+)
detection (96.1%), but all the HPV genotyping tests showed a
higher specificity. (Anyplex 86.8%; Linear Array 86.0%; GP5+/6+
78.8%; CLART2 76.5%). The agreement between HC2 results and the
other techniques was similar: 82.4%, kappa=0.650 for Anyplex;
83.4%, kappa=0.670 for Linear Array, 79.93%, kappa=0.609 for
GP5+/6+ and 82.4%, kappa=0.654 for CLART2. HPV 16 and/or 18
infection was a risk factor for underlying HSIL+ in the
univariate analysis. Anyplex showed the highest risk of
underlying HSIL+ after positive HPV 16 and/or 18 tests (OR 31.1;
95% IC 12.1-80.0)
Methane, ammonia, and their irradiation products at the surface of an intermediate-size KBO? A portrait of Plutino (90482) Orcus
Orcus is an intermediate-size 1000km-scale Kuiper Belt Object in 3:2
mean-motion resonance with Neptune, in an orbit very similar to that of Pluto.
We present visible and near-infrared photometry and spectroscopy obtained with
the Keck 10m-telescope and the Gemini 8m-telescope . We confirm the unambiguous
detection of crystalline water ice as well as absorption in the 2.2\mu m
region. Both in the visible and near-infrared Orcus' spectral properties appear
to be homogeneous over time (and probably rotation) at the resolution
available. From Hapke radiative transfer models involving intimate mixtures of
various ices we find for the first time that ammonium (NH+4) and traces of
ethane (C2 H6), which are most probably solar irradiation products of ammonia
and methane, and a mixture of methane and ammonia (diluted or not) are the best
candidates to improve the description of the data with respect to a simple
water ice mixture (Haumea type surface). The possible more subtle structure of
the 2.2\mu m band(s) should be investigated thoroughly in the future for Orcus
and other intermediate size Plutinos to better understand the methane and
ammonia chemistry at work, if any. We investigated the thermal history of Orcus
with a new 3D thermal evolution model. Simulations over 4.5 x109 yrs with an
input 10% porosity, bulk composition of 23% amorphous water ice and 77% dust,
and cold accretion show that even with the action of long-lived radiogenic
elements only, Orcus should have a melted core and most probably suffered a
cryovolcanic event in its history which brought large amounts of crystalline
ice to the surface. The presence of ammonia in the interior would strengthen
the melting process. The crystalline water ice possibly brought to the surface
by a past cryovolcanic event sbe detectable after several billion years despite
the irradiation eects, as demonstrated by recent laboratory experiments.Comment: 15 pages, 9 figure
Valoración ambiental de vivienda rural tipo con el método de la eMergía
En este trabajo se presentan las principales características de tres tipos de vivienda rural (considerando sus materiales y su tipología estructural), del municipio de Yajalón (Chiapas), y se realiza su valoración ambiental, por medio de un análisis emergético por insumos. Se hicieron 30 visitas de campo, a fin de recabar la información necesaria para llevar a cabo este estudio. Además de esta información, se utilizaron el catálogo de conceptos de obra, y los gastos de mantenimiento y operación para obtener, mediante la eMergía, los índices emergéticos correspondientes y de esta manera determinar la sostenibilidad de estas viviendas
A Semiautomated Classification System for Producing Service Directories in Social and Health Care (DESDE-AND): Maturity Assessment Study
Background: DESDE-LTC (Description and Evaluation of Services and DirectoriEs for Long-Term Care) is an international classification system that allows standardized coding and comparisons between different territories and care sectors, such as health and social care, in defined geographic areas. We adapted DESDE-LTC into a computer tool (DESDE-AND) for compiling a directory of care services in Andalucia, Spain.
Objective: The aim of this study was to evaluate the maturity of DESDE-AND. A secondary objective of this study is to show the practicality of a new combined set of standard evaluation tools for measuring the maturity of health technology products.
Methods: A system for semiautomated coding of service provision has been co-designed. A panel of 23 domain experts and a group of 68 end users participated in its maturity assessment that included its technology readiness level (TRL), usability, validity, adoption (Adoption Impact Ladder [AIL]), and overall degree of maturity [implementation maturity model [IMM]). We piloted the prototype in an urban environment (Seville, Spain).
Results: The prototype was demonstrated in an operational environment (TRL 7). Sixty-eight different care services were coded, generating fact sheets for each service and its geolocation map. The observed agreement was 90%, with moderate reliability. The tool was partially adopted by the regional government of Andalucia (Spain), reaching a level 5 in adoption (AIL) and a level 4 in maturity (IMM) and is ready for full implementation.
Conclusions: DESDE-AND is a usable and manageable system for coding and compiling service directories and it can be used as a core module of decision support systems to guide planning in complex cross-sectoral areas such as combined social and health care
Caracterización de pacientes en edad pediátrica con nevos melanocíticos
Fundamento: Los nevos melanocíticos son lesiones cutáneas benignas muy frecuentes que se encuentran en la totalidad de la población. Son proliferaciones derivadas de los melanocitos, las células responsables de la pigmentación normal de la piel.Objetivo: caracterizar los pacientes en edad pediátrica portadores de nevos melanocíticos.Métodos: estudio descriptivo de serie de casos. Fueron estudiados todos los pacientes (N=174) con nevos melanocíticos (N=194) que acudieron a la consulta especializada del Hospital Pediátrico Paquito González Cueto, en el período comprendido desde noviembre de 2013 hasta a noviembre de 2014. Parte de la información fue tomada de las historias clínicas. Se realizó diagnóstico clínico y dermatoscópico de los nevos. Para clasificar las lesiones según el grado de malignidad, se aplicó el índice dermatoscópico total.Resultados: predominaron los pacientes de nueve años de edad, así como los de sexo femenino y color blanco de la piel. El 74 % de los pacientes presentó antecedentes patológicos familiares de nevos. Los nevos adquiridos fueron los más frecuentes (44,2 %), seguidos de los congénitos (42,5 %). En el puntaje dermatoscópico predominaron los nevos benignos con 90,7 %. En el 29,4 % de las biopsias indicadas no se correspondió el diagnóstico clínico con el histológico.Conclusión: en pacientes pediátricos es importante la vigilancia de la aparición de nevos fundamentalmente en edades próximas a la pubertad, y en niños de piel blanca. Tanto el diagnóstico clínico como el dermatoscópico son importantes, pero el estudio histológico es imprescindible cuando existe sospecha de lesiones malignas o con tendencia a malignizarse.</p
Oviposición de Anastrepha obliqua (Macquart, 1835) (Diptera: Tephritidae) sobre frutos de Spondias purpurea L. (Sapindales: Anacardiaceae)
El complejo del género Anastrepha spp. está formado por especies de importancia económica que infestan una amplia variedad de frutas en la región tropical y subtropical. El objetivo del presente estudio fue describir el comportamiento y ciclo biológico asociado al ataque de Anastrepha obliqua (Macquart, 1835) sobre la especie Spondias purpurea L. Se realizaron observaciones biológicas en Alto de la Arena, corregimiento de Veladero, distrito de Tolé, provincia de Chiriquí, Panamá, donde se recolectaron un total de 12 frutos de Spondias purpurea L., se llevaron al laboratorio y se anotaron los datos del ciclo biológico y de comportamiento diariamente. Se determinó que el ciclo biológico de Anastrepha obliqua (Macquart, 1835) tiene duración aproximada de 30 a 32 días en el laboratorio; el estado inmaduro de pupa es el estadio que presentó mayor mortalidad, posiblemente debido a las condiciones ambientales del laboratorio, que podrían estar influyendo en el inicio de este estadio de forma prematura o tardía. Se considera que el momento oportuno para tomar medidas de control sobre esta plaga en los diferentes cultivos frutales es durante la salida de las larvas los frutos, cuando son más vulnerables para el ataque de enemigos naturales o controles biológicos
Caracterización de pacientes en edad pediátrica con nevos melanocíticos
Fundamento: Los nevos melanocíticos son lesiones cutáneas benignas muy frecuentes que se encuentran en la totalidad de la población. Son proliferaciones derivadas de los melanocitos, las células responsables de la pigmentación normal de la piel.Objetivo: caracterizar los pacientes en edad pediátrica portadores de nevos melanocíticos.Métodos: estudio descriptivo de serie de casos. Fueron estudiados todos los pacientes (N=174) con nevos melanocíticos (N=194) que acudieron a la consulta especializada del Hospital Pediátrico Paquito González Cueto, en el período comprendido desde noviembre de 2013 hasta a noviembre de 2014. Parte de la información fue tomada de las historias clínicas. Se realizó diagnóstico clínico y dermatoscópico de los nevos. Para clasificar las lesiones según el grado de malignidad, se aplicó el índice dermatoscópico total.Resultados: predominaron los pacientes de nueve años de edad, así como los de sexo femenino y color blanco de la piel. El 74 % de los pacientes presentó antecedentes patológicos familiares de nevos. Los nevos adquiridos fueron los más frecuentes (44,2 %), seguidos de los congénitos (42,5 %). En el puntaje dermatoscópico predominaron los nevos benignos con 90,7 %. En el 29,4 % de las biopsias indicadas no se correspondió el diagnóstico clínico con el histológico.Conclusión: en pacientes pediátricos es importante la vigilancia de la aparición de nevos fundamentalmente en edades próximas a la pubertad, y en niños de piel blanca. Tanto el diagnóstico clínico como el dermatoscópico son importantes, pero el estudio histológico es imprescindible cuando existe sospecha de lesiones malignas o con tendencia a malignizarse.</p
- …