769 research outputs found
The Green Bank Northern Celestial Cap Pulsar Survey - I: Survey Description, Data Analysis, and Initial Results
We describe an ongoing search for pulsars and dispersed pulses of radio
emission, such as those from rotating radio transients (RRATs) and fast radio
bursts (FRBs), at 350 MHz using the Green Bank Telescope. With the Green Bank
Ultimate Pulsar Processing Instrument, we record 100 MHz of bandwidth divided
into 4,096 channels every 81.92 . This survey will cover the entire sky
visible to the Green Bank Telescope (, or 82% of the sky)
and outside of the Galactic Plane will be sensitive enough to detect slow
pulsars and low dispersion measure (30 ) millisecond
pulsars (MSPs) with a 0.08 duty cycle down to 1.1 mJy. For pulsars with a
spectral index of 1.6, we will be 2.5 times more sensitive than previous and
ongoing surveys over much of our survey region. Here we describe the survey,
the data analysis pipeline, initial discovery parameters for 62 pulsars, and
timing solutions for 5 new pulsars. PSR J02145222 is an MSP in a long-period
(512 days) orbit and has an optical counterpart identified in archival data.
PSR J06365129 is an MSP in a very short-period (96 minutes) orbit with a
very low mass companion (8 ). PSR J06455158 is an isolated MSP
with a timing residual RMS of 500 ns and has been added to pulsar timing array
experiments. PSR J14347257 is an isolated, intermediate-period pulsar that
has been partially recycled. PSR J18164510 is an eclipsing MSP in a
short-period orbit (8.7 hours) and may have recently completed its spin-up
phase.Comment: 18 pages, 10 figures, 5 tables, accepted by Ap
The Green Bank North Celestial Cap Pulsar Survey. IV: Four New Timing Solutions
We present timing solutions for four pulsars discovered in the Green Bank
Northern Celestial Cap (GBNCC) survey. All four pulsars are isolated with spin
periods between 0.26s and 1.84s. PSR J00382501 has a 0.26s
period and a period derivative of ,
which is unusually low for isolated pulsars with similar periods. This low
period derivative may be simply an extreme value for an isolated pulsar or it
could indicate an unusual evolution path for PSR J00382501, such as a
disrupted recycled pulsar (DRP) from a binary system or an orphaned central
compact object (CCO). Correcting the observed spin-down rate for the Shklovskii
effect suggests that this pulsar may have an unusually low space velocity,
which is consistent with expectations for DRPs. There is no X-ray emission
detected from PSR J00382501 in an archival swift observation, which suggests
that it is not a young orphaned CCO. The high dispersion measure of PSR
J1949+3426 suggests a distance of 12.3kpc. This distance indicates that PSR
J1949+3426 is among the most distant 7% of Galactic field pulsars, and is one
of the most luminous pulsars.Comment: 7 pages, 5 figure
The Green Bank Northern Celestial Cap Pulsar Survey II: The Discovery and Timing of Ten Pulsars
We present timing solutions for ten pulsars discovered in 350 MHz searches
with the Green Bank Telescope. Nine of these were discovered in the Green Bank
Northern Celestial Cap survey and one was discovered by students in the Pulsar
Search Collaboratory program in analysis of drift-scan data. Following
discovery and confirmation with the Green Bank Telescope, timing has yielded
phase-connected solutions with high precision measurements of rotational and
astrometric parameters. Eight of the pulsars are slow and isolated, including
PSR J09302301, a pulsar with nulling fraction lower limit of 30\% and
nulling timescale of seconds to minutes. This pulsar also shows evidence of
mode changing. The remaining two pulsars have undergone recycling, accreting
material from binary companions, resulting in higher spin frequencies. PSR
J05572948 is an isolated, 44 \rm{ms} pulsar that has been partially recycled
and is likely a former member of a binary system which was disrupted by a
second supernova. The paucity of such so-called `disrupted binary pulsars'
(DRPs) compared to double neutron star (DNS) binaries can be used to test
current evolutionary scenarios, especially the kicks imparted on the neutron
stars in the second supernova. There is some evidence that DRPs have larger
space velocities, which could explain their small numbers. PSR J1806+2819 is a
15 \rm{ms} pulsar in a 44 day orbit with a low mass white dwarf companion. We
did not detect the companion in archival optical data, indicating that it must
be older than 1200 Myr.Comment: 9 pages, 5 figure
Parallel Generation of Association Rules – Use Case: Psychometric Evaluation
Mining of association rules consists of determining relations among variables in the form of rules in large databases, one of the algorithms most used to perform this task is the Apriori algorithm. This article proposes the parallelization of the Apriori algorithm applied to the Cattell’s questionnaire Sixteen Personality Factor, known as the 16PF questionnaire, to generate association rules among different questions. The use case used has a database that contains 49,150 questionnaires answered, with 163 questions per questionnaire. Results obtained show four times less execution time between the proposed parallel algorithm and the serial algorithm, in addition, the results show associations with confidence values greater than 97% (with two variables) and greater than 98% (with three variables), which it would be expected from the point of view of traditional psychology.
Keywords: rules of association, Apriori algorithm, parallelization, personality questionnair
Quemerina, omentina-1 y miR-103p y su relación con la diabetes mellitus gestacional
Diversos genes pueden desencadenar la diabetes mellitus gestacional (DMG), considerada como un problema de salud pública de etiologÃa compleja y multifactorial.
Objetivo: presentar una revisión de tema de la evidencia cientÃfica disponible sobre el impacto de la expresión de los genes omentina-1, quemerina y miR-1013p, implicados en el desarrollo de la DMG.
Materiales y métodos: se realizó una búsqueda de estudios electrónicos transversales a través de la base de datos registrados en MEDLINE y PUBMED, publicados durante 2010-2019, que valoraran mediciones de los tres genes en mujeres con DMG.
Resultados: ocho artÃculos cumplieron con los criterios de inclusión, cuatro artÃculos midieron los niveles de quemerina, tres de omentina-1 y uno de miR-103p. Entre los niveles de quemerina se mostró que la circulación de quemerina y miR103p se correlacionó positivamente con las variables metabólicas durante el primer y tercer trimestre del embarazo. Se demostró que la liberación de omentina-1 fue mayor en el tejido adiposo vs. placenta cuando se presenta obesidad.
Conclusión: la expresión de genes y la presencia de obesidad están relacionados con el desarrollo de la diabetes mellitus gestacional
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