bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tratamiento quirúrgico de la epilepsia en pacientes con cavernomas. Revisión bibliográfica
Authors: Rojas Zalazar Francisco José 
Published: October 2019

Los cavernomas representan un 5-10% de las malformaciones vasculares encefálicas y espinales. La manifestación clínicamás frecuente de los cavernomas supratentoriales son las crisis epilépticas, se estima que el riesgo de recurrencia luego deuna primera crisis es de un 94% y que un 35-40% de estos pacientes desarrollan epilepsia refractaria. El objetivo de esta revisión es realizar una puesta al día sobre el rol del tratamiento quirúrgico precoz en pacientes con crisis esporádicas y el tratamiento en paciente con epilepsia refractaria. Además, se mencionan las consideraciones en el tratamiento de cavernomas temporales y extratemporales. Para planificar la cirugía es necesario un adecuado estudio preoperatorio, considerar la localización de la lesión, y tiempo de evolución de la epilepsia. El tratamiento quirúrgico ofrece buenos resultados, un 75% de los pacientes están libres de crisis epilépticas luego de la cirugía, con mejores resultados en pacientes no refractarios a fármacos.
Unusual intracranial melanoma: a case report
Authors: Cougo Samueli Pedro , Nunes Rabelo Nícollas , Honorato Pereira Vítor Hugo , Nunes Rabelo Neiffer , Araujo Dias Junior Luiz Antonio , Pereira Carlos Umberto 
Published: October 2019

Introducción: Los melanomas son tumores cutáneos malignos de melanocitos. Tienen un gran potencial de metastización. El tercer sitio más acometido es el parénquima cerebral (20% a 25%). Generalmente, las metástasis intracraneales ocurren en las fases más avanzadas del cáncer. Alrededor del 50% de los casos no presentan manifestaciones clínicas. El objetivo del texto es ilustrar las dificultades diagnósticas entre las lesiones expansivas cerebrales, ilustrando un caso de tumor. Relato de caso: Paciente masculino, 43 años, inicialmente, cursó con cefalea crónica agudizada de inicio insidioso en regiónes bitemporal, con irradiación para región occipital. Se sometió a (CT) que al principio evidenció lesión expansiva en la fosa posterior a la izquierda que se presentaba como un hematoma hipertensivo. Realizada la craniectomía, se evidenció lesión ennegreciday sangrante, descartando la hipótesis inicial de hematoma hipertensivo, con estudio anatomopatológico confirmando eldiagnóstico de melanoma. Discusión: Muchos casos no presentan manifestaciones clínicas evidentes, los efectos de masapueden ser similares entre los tumores primarios, de los oriundos de metástasis o de lesiones hemorrágicas de un accidente cerebrovascular. En casos con sospechas de metástasis, la resonancia magnética con gadolinio es el método principal de diagnóstico y el método de elección para descartar diagnósticos diferenciales. La resección quirúrgica se considera patrón de oro en el tratamiento. Conclusión: Las metástasis cerebrales de melanomas presentan diversos diagnósticos diferenciales en diferentes localidades. Es de suma importancia, para equipo de neurocirujanos, pensar en los diagnósticos diferenciales de esas lesiones.
Space Densities and Emissivities of Active Galactic Nuclei at z > 4
Authors: Giallongo E. , Grazian A. , Fiore F. , Kodra D. , Urrutia T. , Castellano M. , Cristiani S. , Dickinson M. , Fontana A. , Menci N. , Pentericci L. , Boutsia K. , Newman J. A. , Puccetti S. 
Published: October 2019

Abstract
The study of the space density of bright active galactic nuclei (AGNs) at z > 4 has been subject to extensive effort given its importance in the estimation of cosmological ionizing emissivity and growth of supermassive black holes. In this context we have recently derived high space densities of AGNs at z ∼ 4 and −25 < M
1450 < −23 in the Cosmic Evolution Survey (COSMOS) field from a spectroscopically complete sample. In the present paper we attempt to extend the knowledge of the AGN space density at fainter magnitudes (−22.5 < M
1450 < −18.5) in the 4 < z < 6.1 redshift interval by means of a multiwavelength sample of galaxies in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) GOODS-South, GOODS-North, and EGS fields. We use an updated criterion to extract faint AGNs from a population of near-IR (rest-frame UV) selected galaxies at photometric z > 4 showing X-ray detection in deep Chandra images available for the three CANDELS fields. We have collected a photometric sample of 32 AGN candidates in the selected redshift interval, six of which having spectroscopic redshifts. Including our COSMOS sample as well as other bright QSO samples allows a first guess on the shape of the UV luminosity function (LF) at z ∼ 4.5. The resulting emissivity and photoionization rate appear consistent with that derived from the photoionization level of the intergalactic medium at z ∼ 4.5. An extrapolation to z ∼ 5.6 suggests an important AGN contribution to the ionization of intergalactic medium if there are no significant changes in the shape of the UV LF.
Can an Unobserved Concentration of Magnetic Flux Above the Poles of the Sun Resolve the Open Flux Problem?
Authors: Riley Pete , Linker Jon A. , Mikic Zoran , Caplan Ronald M. , Downs Cooper , Thumm Jean-Luc 
Published: October 2019

Abstract
Global models of the extended solar corona, driven by observed photospheric magnetic fields, generally cannot reproduce the amplitude of the measured interplanetary magnetic field at 1 au (or elsewhere in the heliosphere), often underestimating it by a factor of two or more. Some modelers have attempted to resolve this “open flux” problem by adjusting what they believe to be errors in the estimates of the photospheric field values. Others have simply multiplied interplanetary estimates by some correction factor to match 1 au values. Here, we investigate whether this “missing” flux can be explained by a source of largely unobserved, concentrated bundles of flux in the photosphere at latitudes too high to be adequately resolved by ground-based observatories or Earth-based spacecraft. Using potential field source-surface and magnetohydrodynamic models, we demonstrate that this additional polar flux can (at least partially) resolve the open flux problem, without generating any new observational discrepancies. For example, we show that model solutions without this additional flux systematically produce streams lying at higher hello-latitudes than is inferred from observations. More importantly, adding this polar flux to the models does not substantially change the location or size of computed coronal holes. The upcoming joint ESA/NASA Solar Orbiter mission may be able to support or refute this idea.
When Does the Onset of Multiple Stellar Populations in Star Clusters Occur. II. No Evidence of Multiple Stellar Populations in Lindsay 113
Authors: Li Chengyuan , Wang Yue , Milone Antonino P. 
Published: October 2019

Abstract
The presence of multiple populations (MPs) in almost all globular clusters (GCs) older than ∼10 Gyr has drawn lots of attention. Recently, cumulative evidence has indicated that extragalactic GCs that are older than 2 Gyr seem to also harbor MPs; however, those that are younger than 2 Gyr do not. These observations seem to imply that age is a primary property that controls the presence of MPs in star clusters. However, because of the lack of studies of intermediate-age (∼2–6 Gyr old), low-mass clusters, it is unclear if the cluster mass, in addition to age, also plays a role in the occurrence of MPs. In this work, we studied a ∼4 Gyr old, low-mass (∼23,000 M
⊙) cluster, Lindsay-113, in the Small Magellanic Cloud. Using Hubble Space Telescope photometry, we found that the width of the red-giant branch in this cluster, when measured in a specific color index that is sensitive to star-to-star chemical variations, can be adequately explained by a “simple” stellar population model with some possible noises contributed from measurement uncertainty, photometric artifact, and differential reddening. The comparison of observations with predictions from synthetic spectra indicates that the internal chemical spread in nitrogen abundance, which is a signature of MPs, would not exceed 0.2 dex. Since Lindsay 113 is significantly older than other GCs with MPs, we suggest that the onset of MPs is likely determined by the combination of cluster age and mass.
Neutrino-driven Instability of Ion Acoustic Waves in an Ultrarelativistic Degenerate Plasma
Authors: Ghai Yashika , Saini N. S. , Eliasson B. 
Published: October 2019

Abstract
The coupling between ion acoustic waves (IAWs) and a neutrino beam undergoing flavor oscillations in a dense, relativistically degenerate plasma is analyzed. The neutrino-driven streaming instability of the IAWs is investigated with relevance to plasma conditions at the last stage of stellar evolution in a massive supernova progenitor. The influence of neutrino beam parameters such as the energy of the incident neutrino beam and eigenfrequency of the neutrino flavor oscillations on the instability growth rate is obtained numerically. It is observed that the neutrino flavor oscillations significantly affect the neutrino-driven instability of the IAWs. Our results also indicate that the time period for the onset of the streaming neutrino-driven instability is shorter than the typical time period of a core-collapse supernova explosion. The findings of this investigation may shed new light on the understanding of the underlying physical mechanism responsible for the core-collapse supernova.
Revisiting the Spectral and Timing Properties of NGC 4151
Authors: Zoghbi A. , Miller J. M. , Cackett E. 
Published: October 2019

Abstract
NGC 4151 is the brightest Seyfert 1 nucleus in X-rays. It was the first object to show short time delays in the Fe K band, which were attributed to relativistic reverberation, providing a new tool for probing regions at the black hole scale. Here we report the results of a large XMM-Newton campaign in 2015 to study these short delays further. Analyzing high-quality data that span timescales between hours and decades, we find that neutral and ionized absorption contributes significantly to the spectral shape. Accounting for their effects, we find no evidence for a relativistic reflection component, contrary to early work. Energy-dependent lags are significantly measured in the new data, but with an energy profile that does not resemble a broad iron line, in contrast to the old data. The complex lag-energy spectra, along with the lack of strong evidence for a relativistic spectral component, suggest that the energy-dependent lags are produced by absorption effects. The long-term spectral variations provide new details on the variability of the narrow Fe Kα line. We find that its variations are correlated with, and delayed with respect to, the primary X-ray continuum. We measure a delay of

days, implying an origin in the inner broad-line region (BLR). The delay is half the Hβ line delay, suggesting a geometry that differs slightly from the optical BLR.
Precursors in Short Gamma-Ray Bursts as a Possible Probe of Progenitors
Authors: Zhong Shu-Qing , Dai Zi-Gao , Cheng Ji-Gui , Lan Lin , Zhang Hai-Ming 
Published: October 2019

Abstract
We extract 18 candidate short gamma-ray bursts (SGRBs) with precursors from 660 SGRBs observed by the Fermi and Swift satellites, and carry out a comprehensive analysis of their temporal and spectral features. We obtain the following results: (1) for a large fraction of candidates, the main burst durations are longer than their precursor durations, comparable to their quiescent times from the end of precursors to the beginning of their main bursts. (2) The average flux of precursors tends to increase as their main bursts brighten. (3) As seen from the distributions of hardness ratio and spectral fitting, the precursors are slightly spectrally softer with respect to the main bursts. Moreover, a significant portion of precursors and all main bursts favor a non-thermal spectrum. (4) The precursors might be a probe of the progenitor properties of SGRBs such as the magnetic field strength and the crustal equation of state if they arise from some processes before mergers of binary compact objects rather than post-merger processes.
Testing the Tremaine–Weinberg Method Applied to Integral-field Spectroscopic Data Using a Simulated Barred Galaxy
Authors: Zou Yanfei , Shen Juntai , Bureau Martin , Li Zhao-Yu 
Published: October 2019

Abstract
Tremaine and Weinberg (TW) proposed a conceptually simple procedure relying on long-slit spectroscopy to measure the pattern speeds of bars (Ωp) in disk galaxies. Using a simulated galaxy, we investigate the potential biases and uncertainties of TW measurements using increasingly popular integral-field spectrographs (IFSs), for which multiple pseudo-slits (and thus independent measurements) can be constructed with a single observation. Most importantly, to establish the spatial coverage required and ensure the validity of the measurements, the inferred Ωp must asymptotically converge as the (half-)length of each pseudo-slit used is increased. The requirement for our simulation is to reach ≈1.3 times the half-light radius, but this may vary from galaxy to galaxy. Only those slits located within the bar region yield accurate measurements. We confirm that the position angle of the disk is the dominant source of systematic error in TW Ωp measurements, leading to under/overestimates of tens of percent for inaccuracies of even a few degrees. Recasting the data so that the data grid aligns with the disk major axis leads to slightly reduced uncertainties. Accurate measurements are obtained only for well-defined ranges of the bar angle (relative to the galaxy major axis) ϕ
bar and the inclination angle i, here 10° ≲ ϕ
bar ≲ 75° and 105° ≲ ϕ
bar ≲ 170° and 15° ≲ i ≲ 70°. The adopted (pseudo-)slit widths, spatial resolution, and (unless extremely aggressive) spatial binning of IFS data have no significant impact on the measurements. Our results thus provide useful guidelines for reliable and accurate direct Ωp measurements with IFS observations.
Choosing a Maximum Drift Rate in a SETI Search: Astrophysical Considerations
Authors: Sheikh Sofia Z. , Wright Jason T. , Siemion Andrew , Enriquez J. Emilio 
Published: October 2019

Abstract
A radio transmitter that is accelerating with a non-zero radial component with respect to a receiver will produce a signal that appears to change its frequency over time. This effect, commonly produced in astrophysical situations where orbital and rotational motions are ubiquitous, is called a drift rate. In radio SETI (Search for Extraterrestrial Intelligence) research, it is unknown a priori which frequency a signal is being sent at, or even if there will be any drift rate at all besides motions within the solar system. Therefore drift rates across the potential range need to be individually searched and a maximum drift rate needs to be chosen. The middle of this range is zero, indicating no acceleration, but the absolute value for the limits remains unconstrained. A balance must be struck between computational time and the possibility of excluding a signal from an ETI. In this work, we examine physical considerations that constrain a maximum drift rate and highlight the importance of this problem in any narrowband SETI search. We determine that a normalized drift rate of 200 nHz (e.g., 200 Hz s−1 at 1 GHz) is a generous, physically motivated guideline for the maximum drift rate that should be applied to future narrowband SETI projects if computational capabilities permit.
Substellar Companions of the Young Weak-line TTauri Star DoAr21
Authors: Curiel Salvador , Ortiz-León Gisela N. , Mioduszewski Amy J. , Torres Rosa M. 
Published: October 2019

Abstract
The compact, nonthermal emission in DoAr21 has been studied with the Very Long Baseline Array (VLBA) to investigate the possibility that the residuals of the astrometry fitting are due to the reflex motion induced by a possible companion. We find that the fitting of VLBA astrometric observations of DoAr21 improves significantly by adding the orbital motions of three companions. We obtain an improved distance to the source of 134.6 ± 1.0 pc, and estimate that the central star, DoAr21, has a mass of about 2.04 ± 0.70 M
⊙. We suggest that DoAr21 represents a unique case where two substellar companions, DoAr21b and DoAr21c (m

b
∼ 35.6 ± 27.2 M
jup and m

c
∼ 44.0 ± 13.6 M
jup, respectively), have been found to be associated with a relatively low-mass, pre-main sequence star. In addition, we find that this WTTau star is an astrometric double system, having a low-mass star companion, DoAr21B (m

B
∼ 0.35 ± 0.12 M
⊙), in a relatively eccentric orbit. The orbit of this low-mass stellar companion is compact, while the brown dwarfs are located in external orbits. DoAr21c has the strongest astrometric signature in the periodogram, while DoAr21B has a weak but significant signature. On the other hand, the astrometric signature of DoAr21b does not appear in the periodogram, however, this brown dwarf was directly detected in some of the VLBA observations. The estimated orbital periods of DoAr21B, DoAr21b, and DoAr21c are P

B
∼ 92.92 ± 0.02, P

b
∼ 450.9 ± 3.8, and P

c
∼ 1013.5 ± 25.3 days, respectively. Since the estimated age of this young star is about 0.4–0.8 Myr, the detected brown dwarf companion is among the youngest companions observed to date.
“A Chance to Try”: Exploring the Clinical Utility of Shared-Control Teleoperation for Powered Wheelchair Assessment and Training
Authors: Smith Emma M. , Rismani Shalaleh , Ben Mortenson W. , Mihailidis Alex , Miller William C. 
Published: October 2019

Abstract
Importance: Powered wheelchairs provide independence for people with mobility impairments; however, current training practices may not meet the needs of those with cognitive impairments. Shared-control teleoperation may have utility in a clinical setting when developing training suited to this population.
Objective: To explore the clinical utility of a shared-control teleoperation device for powered wheelchair assessment and training.
Design: In this qualitative study, we used two sequential semistructured interviews conducted a minimum of 2 wk apart. Thematic analyses were used with member checking, reflexive journaling, and triangulation of researchers to establish trustworthiness of the data.
Setting: Rehabilitation center and residential care and community settings.
Participants: Using purposive sampling, we recruited occupational therapists and physical therapists who were mostly female and who had a range of practice experience.
Results: Fifteen participants were interviewed, and two primary themes were identified: (1) “A big enabler” described how shared control provides opportunities to train people who may otherwise be denied powered mobility, and (2) “changing the learner experience” described how shared control may promote success in skill development through an alternative learning experience.
Conclusions and Relevance: Shared-control technology may have the potential to broaden the scope of therapeutic intervention by reducing risk to the driver and others in the environment and by facilitating alternative training approaches.
What This Article Adds: Technological advances that allow more control over a powered wheelchair by a clinician, known as shared control, may provide learning opportunities for people who are otherwise denied access to powered mobility. Shared control may also allow the use of new instructional techniques, increase safety in the training process, and reduce anxiety associated with learning.
Associations Between Meaning of Everyday Activities and Participation Among Children
Authors: Rosenberg Limor , Pade Margalit , Reizis Hila , Bar Michal Avrech 
Published: October 2019

Abstract
Importance: The subjective meaning that people attach to their occupations may explain the association among participation, health, and well-being. To date, the subjective meaning of occupation among children has mostly been studied through qualitative studies. No study has yet quantitatively assessed the perceived meaning of everyday activities among children. Moreover, no study has assessed the associations between perceived meaning and actual participation.
Objective: To explore the perceived meaning—value, challenge, felt time, and autonomy—that typically developing children attribute to their everyday activities and to assess the correlations between children’s perceived meaning and their participation as assessed by parents.
Design: Cross-sectional study.
Setting: Community.
Participants: A convenience sample of 60 Israeli children (ages 6–12 yr) and their parents.
Outcomes and Measures: Parents completed the Children Participation Questionnaire–School, and children completed the Perceived Meaning of Occupation Questionnaire (PMOQ).
Results: Children valued their activities, they perceived the challenge as low, they felt that the time was almost equally distributed between time passing quickly and passing slowly, and they felt autonomous. The subjective perceived meanings were moderately correlated with the children’s actual participation.
Conclusions and Relevance: Children are capable of reflecting on the meaning of their everyday activities. The PMOQ may assist occupational therapy practitioners in eliciting their young clients’ perspectives regarding their everyday occupations. The results contribute to the occupational science literature in the context of child development.
What This Article Adds: The PMOQ enables children to reflect on their subjective perceived meanings of occupations. The subjective perceived meanings of occupations are moderately correlated with the children’s actual participation. The PMOQ may broaden the potential pathways to facilitating children’s meaningful participation in everyday occupations.
Association of Sleep and Hand Function in People With Carpal Tunnel Syndrome
Authors: Goorman Angela Messer , Dawson Spencer , Schneck Colleen , Pierce Doris 
Published: October 2019

Abstract
This study examined whether sleep quality is associated with hand function above and beyond what can be explained by the effect of pain and carpal tunnel syndrome (CTS) severity on hand function in clients with CTS. The sample included 53 adults ages 30–86 yr. The Manual Ability Measure–20, Pittsburgh Sleep Quality Index, visual analog scale for pain, and electromyography for CTS diagnosis and severity level were used to measure outcomes. Sleep quality was significantly associated with manual ability after controlling for CTS severity and pain. In CTS care, attention to sleep is significant because it may promote hand function.