948 research outputs found
Construction and characterization of a partial binary bacterial artificial chromosome (BIBAC) of Agave tequilana var. azul (2X) and its application for gene identification
The structure and organization of the genome of Agave is still unknown. To provide a genomic tool for searching sequences of the genus, we built and characterized a binary (BIBAC2) genomic library of Agave tequilana Weber var. azul. Clones of the library had an average insert size of 170 Kb. The frequency of inserts with internal Not I sites was 30% and only 5% of the library showed organelle contamination. The library was assessed using probes with high homology to repeated regions (retroelements and rDNA regions), genes involved in the resistance to diseases (NBS-LRR) and genes related to late embryogenesis (LEA). Recombinant clones that hybridized with each of the probes were identified. Our results indicate that the obtained genomic library is suitable for the identification of sequences of interest, for genetic mapping and for studies of gene regulation and expression.Key words: Binary bacterial artificial chromosome (BIBAC), Agave tequilana, genome, clones
A disk of dust and molecular gas around a high-mass protostar
The processes leading to the birth of low-mass stars such as our Sun have
been well studied, but the formation of high-mass (> 8 x Sun's mass) stars has
heretofore remained poorly understood. Recent observational studies suggest
that high-mass stars may form in essentially the same way as low-mass stars,
namely via an accretion process, instead of via merging of several low-mass (<
8 Msun) stars. However, there is as yet no conclusive evidence. Here, we report
the discovery of a flattened disk-like structure observed at submillimeter
wavelengths, centered on a massive 15 Msun protostar in the Cepheus-A region.
The disk, with a radius of about 330 astronomical units (AU) and a mass of 1 to
8 Msun, is detected in dust continuum as well as in molecular line emission.
Its perpendicular orientation to, and spatial coincidence with the central
embedded powerful bipolar radio jet, provides the best evidence yet that
massive stars form via disk accretion in direct analogy to the formation of
low-mass stars
Preliminary results using a P300 brain-computer interface speller: a possible interaction effect between presentation paradigm and set of stimuli
Fernández-Rodríguez Á., Medina-Juliá M.T., Velasco-Álvarez F., Ron-Angevin R. (2019) Preliminary Results Using a P300 Brain-Computer Interface Speller: A Possible Interaction Effect Between Presentation Paradigm and Set of Stimuli. In: Rojas I., Joya G., Catala A. (eds) Advances in Computational Intelligence. IWANN 2019. Lecture Notes in Computer Science, vol 11506. Springer, ChamSeveral proposals to improve the performance controlling a P300-based BCI speller have been studied using the standard row-column presentation (RCP) par-adigm. However, this paradigm could not be suitable for those patients with lack of gaze control. To solve that, the rapid serial visual presentation (RSVP) para-digm, which presents the stimuli located in the same position, has been proposed in previous studies. Thus, the aim of the present work is to assess if a stimuli set of pictures that improves the performance in RCP, could also improve the per-formance in a RSVP paradigm. Six participants have controlled four conditions in a calibration task: letters in RCP, pictures in RCP, letters in RSVP and pictures in RSVP. The results showed that pictures in RCP obtained the best accuracy and information transfer rate. The improvement effect given by pictures was greater in the RCP paradigm than in RSVP. Therefore, the improvements reached under RCP may not be directly transferred to the RSVP.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Sources of Relativistic Jets in the Galaxy
Black holes of stellar mass and neutron stars in binary systems are first
detected as hard X-ray sources using high-energy space telescopes. Relativistic
jets in some of these compact sources are found by means of multiwavelength
observations with ground-based telescopes. The X-ray emission probes the inner
accretion disk and immediate surroundings of the compact object, whereas the
synchrotron emission from the jets is observed in the radio and infrared bands,
and in the future could be detected at even shorter wavelengths. Black-hole
X-ray binaries with relativistic jets mimic, on a much smaller scale, many of
the phenomena seen in quasars and are thus called microquasars. Because of
their proximity, their study opens the way for a better understanding of the
relativistic jets seen elsewhere in the Universe. From the observation of
two-sided moving jets it is inferred that the ejecta in microquasars move with
relativistic speeds similar to those believed to be present in quasars. The
simultaneous multiwavelength approach to microquasars reveals in short
timescales the close connection between instabilities in the accretion disk
seen in the X-rays, and the ejection of relativistic clouds of plasma observed
as synchrotron emission at longer wavelengths. Besides contributing to a deeper
comprehension of accretion disks and jets, microquasars may serve in the future
to determine the distances of jet sources using constraints from special
relativity, and the spin of black holes using general relativity.Comment: 39 pages, Tex, 8 figures, to appear in vol. 37 (1999) of Annual
Reviews of Astronomy and Astrophysic
Utilización de Prótesis Testicular Alternativa (artesanal) en la Cátedra de Urología del Hospital de Clínicas, Asunción – Paraguay Facultad de Ciencias Médicas – Universidad Nacional de Asunción
INTRODUDCCIÓN: Las orquiectomías se realizan por razones muy variadas y justificadas. La falta de los testículos no solo puede ocasionar un problema psicológico, sino también físico o estético, por lo que se impone la búsqueda de soluciones alternativas a dicho problema. El objetivo de la presente investigación fue reportar resultados obtenidos con la confección de una prótesis testicular artesanal. MATERIALES Y MÉTODOS: Estudio observacional, analítico, transversal, con muestreo no probabilístico de casos consecutivos, de pacientes sometidos a orquiectomía, entre enero de 2010 y agosto de 2014. Se utilizó como prótesis una sonda de Foley 18 de silicona. Los datos se expresan en proporciones. Para la comparación de los grupos se consideró una p < 0,05 como significativa. RESULTADOS: Incluimos 61 pacientes entre 14 y 89 años (45,5 ± 26,2), 34 (55,7%) procedentes del interior. La indicación fue por cáncer de próstata en 23 (37,7%) casos, cáncer de testículo en 30 (49,2%), torsión de cordón en 7 (11,5%) y por criptorquidia en 1 (1,6%). 22 (36,1%) fueron del lado derecho, 16 (26,2%) izquierdo y 23 (37,7%) bilaterales. 8 (13,1%) fueron ambulatorios y con anestesia local. En 33 (54,1%) se realizó acceso por vía inguinal. Se instiló solución fisiológica al 0,9% en 52 (85,2%) pacientes y en 9 (14,8%) xilocaína gel al 2%. El balón fue insuflado entre 10 cc y 25 cc (15±4,3). 8 (13%) presentaron complicaciones. En cuanto a las asociaciones: diagnóstico y lado (p = 0,000), edad y diagnóstico (p = 0,000), acceso quirúrgico y complicaciones (p = 0,018), diagnóstico y complicaciones (p = 0,085), tipo de complicaciones y acceso quirúrgico (p = 0,001). El costo de la prótesis fue de alrededor de 10 dólares americanos. DISCUSIÓN: La prótesis artesanal testicular constituye una alternativa eficaz, de bajo costo y poca morbilidad
Pedestrian, Crowd, and Evacuation Dynamics
This contribution describes efforts to model the behavior of individual
pedestrians and their interactions in crowds, which generate certain kinds of
self-organized patterns of motion. Moreover, this article focusses on the
dynamics of crowds in panic or evacuation situations, methods to optimize
building designs for egress, and factors potentially causing the breakdown of
orderly motion.Comment: This is a review paper. For related work see http://www.soms.ethz.c
The value of metabolic imaging to predict tumour response after chemoradiation in locally advanced rectal cancer
Preliminary data of this work were presented by RCM and awarded at the 2009 Annual Meeting of the Spanish Society of Coloproctology (AECP) held in Barcelona.Background: We aim to investigate the possibility of using 18F-positron emission tomography/computer tomography (PET-CT) to predict the histopathologic response in locally advanced rectal cancer (LARC) treated with preoperative chemoradiation (CRT).
Methods: The study included 50 patients with LARC treated with preoperative CRT. All patients were evaluated by PET-CT before and after CRT, and results were compared to histopathologic response quantified by tumour regression grade (patients with TRG 1-2 being defined as responders and patients with grade 3-5 as non-responders). Furthermore, the predictive value of metabolic imaging for pathologic complete response (ypCR) was investigated.
Results: Responders and non-responders showed statistically significant differences according to Mandard's criteria for maximum standardized uptake value (SUVmax) before and after CRT with a specificity of 76,6% and a positive predictive value of 66,7%. Furthermore, SUVmax values after CRT were able to differentiate patients with ypCR with a sensitivity of 63% and a specificity of 74,4% (positive predictive value 41,2% and negative predictive value 87,9%); This rather low sensitivity and specificity determined that PET-CT was only able to distinguish 7 cases of ypCR from a total of 11 patients.
Conclusions: We conclude that 18-F PET-CT performed five to seven weeks after the end of CRT can visualise functional tumour response in LARC. In contrast, metabolic imaging with 18-F PET-CT is not able to predict patients with ypCR accuratelyFounded by the Fundación Investigación Mutua Madrileña. We are indebted to M. Expósito Ruiz for statistical support. and to J-L Marín Aznar for pathologic analysisYe
Planet formation in Binaries
Spurred by the discovery of numerous exoplanets in multiple systems, binaries
have become in recent years one of the main topics in planet formation
research. Numerous studies have investigated to what extent the presence of a
stellar companion can affect the planet formation process. Such studies have
implications that can reach beyond the sole context of binaries, as they allow
to test certain aspects of the planet formation scenario by submitting them to
extreme environments. We review here the current understanding on this complex
problem. We show in particular how each of the different stages of the
planet-formation process is affected differently by binary perturbations. We
focus especially on the intermediate stage of kilometre-sized planetesimal
accretion, which has proven to be the most sensitive to binarity and for which
the presence of some exoplanets observed in tight binaries is difficult to
explain by in-situ formation following the "standard" planet-formation
scenario. Some tentative solutions to this apparent paradox are presented. The
last part of our review presents a thorough description of the problem of
planet habitability, for which the binary environment creates a complex
situation because of the presence of two irradation sources of varying
distance.Comment: Review chapter to appear in "Planetary Exploration and Science:
Recent Advances and Applications", eds. S. Jin, N. Haghighipour, W.-H. Ip,
Springer (v2, numerous typos corrected
Radio Emission from Ultra-Cool Dwarfs
The 2001 discovery of radio emission from ultra-cool dwarfs (UCDs), the very
low-mass stars and brown dwarfs with spectral types of ~M7 and later, revealed
that these objects can generate and dissipate powerful magnetic fields. Radio
observations provide unparalleled insight into UCD magnetism: detections extend
to brown dwarfs with temperatures <1000 K, where no other observational probes
are effective. The data reveal that UCDs can generate strong (kG) fields,
sometimes with a stable dipolar structure; that they can produce and retain
nonthermal plasmas with electron acceleration extending to MeV energies; and
that they can drive auroral current systems resulting in significant
atmospheric energy deposition and powerful, coherent radio bursts. Still to be
understood are the underlying dynamo processes, the precise means by which
particles are accelerated around these objects, the observed diversity of
magnetic phenomenologies, and how all of these factors change as the mass of
the central object approaches that of Jupiter. The answers to these questions
are doubly important because UCDs are both potential exoplanet hosts, as in the
TRAPPIST-1 system, and analogues of extrasolar giant planets themselves.Comment: 19 pages; submitted chapter to the Handbook of Exoplanets, eds. Hans
J. Deeg and Juan Antonio Belmonte (Springer-Verlag
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