1,286 research outputs found
The lexical and grammatical sources of neg-raising inferences
We investigate neg(ation)-raising inferences, wherein negation on a predicate can be interpreted as though in that predicate\u27s subordinate clause. To do this, we collect a large-scale dataset of neg-raising judgments for effectively all English clause-embedding verbs and develop a model to jointly induce the semantic types of verbs and their subordinate clauses and the relationship of these types to neg-raising inferences. We find that some neg-raising inferences are attributable to properties of particular predicates, while others are attributable to subordinate clause structure
First Structure Formation: A Simulation of Small Scale Structure at High Redshift
We describe the results of a simulation of collisionless cold dark matter in
a LambdaCDM universe to examine the properties of objects collapsing at high
redshift (z=10). We analyze the halos that form at these early times in this
simulation and find that the results are similar to those of simulations of
large scale structure formation at low redshift. In particular, we consider
halo properties such as the mass function, density profile, halo shape, spin
parameter, and angular momentum alignment with the minor axis. By understanding
the properties of small scale structure formation at high redshift, we can
better understand the nature of the first structures in the universe, such as
Population III stars.Comment: 31 pages, 14 figures; accepted for publication in ApJ. Figure 1 can
also be viewed at http://cfa-www.harvard.edu/~hjang/research
NuSTAR detection of X-ray heating events in the quiet Sun
The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occurring across the whole solar disk. In this Letter, we present the first imaging spectroscopy X-ray observations of three quiet Sun flares during the Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaigns on 2016 July 26 and 2017 March 21, concurrent with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Two of the three events showed time lags of a few minutes between peak X-ray and extreme ultraviolet emissions. Isothermal fits with rather low temperatures in the range 3.2â4.1 MK and emission measures of (0.6â15) Ă 1044 cmâ3 describe their spectra well, resulting in thermal energies in the range (2â6) Ă 1026 erg. NuSTAR spectra did not show any signs of a nonthermal or higher temperature component. However, as the estimated upper limits of (hidden) nonthermal energy are comparable to the thermal energy estimates, the lack of a nonthermal component in the observed spectra is not a constraining result. The estimated Geostationary Operational Environmental Satellite (GOES) classes from the fitted values of temperature and emission measure fall between 1/1000 and 1/100 A class level, making them eight orders of magnitude fainter in soft X-ray flux than the largest solar flares
Development of Body Emotion Perception in Infancy: From Discrimination to Recognition
Research suggests that infants progress from discrimination to recognition of emotions in faces during the first half year of life. It is unknown whether the perception of emotions from bodies develops in a similar manner. In the current study, when presented with happy and angry body videos and voices, 5-month-olds looked longer at the matching video when they were presented upright but not when they were inverted. In contrast, 3.5-month-olds failed to match even with upright videos. Thus, 5-month-olds but not 3.5-month-olds exhibited evidence of recognition of emotions from bodies by demonstrating intermodal matching. In a subsequent experiment, younger infants did discriminate between body emotion videos but failed to exhibit an inversion effect, suggesting that discrimination may be based on low-level stimulus features. These results document a developmental change from discrimination based on non-emotional information at 3.5 months to recognition of body emotions at 5 months. This pattern of development is similar to face emotion knowledge development and suggests that both the face and body emotion perception systems develop rapidly during the first half year of life
Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA
NuSTAR is a highly sensitive focusing hard X-ray (HXR) telescope and has
observed several small microflares in its initial solar pointings. In this
paper, we present the first joint observation of a microflare with NuSTAR and
Hinode/XRT on 2015 April 29 at ~11:29 UT. This microflare shows heating of
material to several million Kelvin, observed in Soft X-rays (SXRs) with
Hinode/XRT, and was faintly visible in Extreme Ultraviolet (EUV) with SDO/AIA.
For three of the four NuSTAR observations of this region (pre-, decay, and post
phases) the spectrum is well fitted by a single thermal model of 3.2-3.5 MK,
but the spectrum during the impulsive phase shows additional emission up to 10
MK, emission equivalent to A0.1 GOES class. We recover the differential
emission measure (DEM) using SDO/AIA, Hinode/XRT, and NuSTAR, giving
unprecedented coverage in temperature. We find the pre-flare DEM peaks at ~3 MK
and falls off sharply by 5 MK; but during the microflare's impulsive phase the
emission above 3 MK is brighter and extends to 10 MK, giving a heating rate of
about erg s. As the NuSTAR spectrum is purely
thermal we determined upper-limits on the possible non-thermal bremsstrahlung
emission. We find that for the accelerated electrons to be the source of the
heating requires a power-law spectrum of with a low energy
cut-off keV. In summary, this first NuSTAR microflare
strongly resembles much more powerful flares.Comment: Accepted for publication in ApJ. 14 pages with 12 figures and 1 tabl
Further Evidence of Early Development of Attention to Dynamic Facial Emotions: Reply to Grossmann and Jessen
Adults exhibit enhanced attention to negative emotions like fear, which is thought to be an adaptive reaction to emotional information. Previous research, mostly conducted with static faces, suggests that infants exhibit an attentional bias toward fearful faces only at around 7 months of age. In a recent study (Journal of Experimental Child Psychology, 2016, Vol. 147, pp. 100â110), we found that 5-month-olds also exhibit heightened attention to fear when tested with dynamic face videos. This indication of an earlier development of an attention bias to fear raises questions about developmental mechanisms that have been proposed to underlie this function. However, Grossmann and Jessen (Journal of Experimental Child Psychology, 2016, Vol. 153, pp. 149â154) argued that this result may have been due to differences in the amount of movement in the videos rather than a response toemotional information. To examine this possibility, we tested a new sample of 5-month-olds exactly as in the original study (Heck, Hock, White, Jubran, & Bhatt, 2016) but with inverted faces. We found that the fear bias seen in our study was no longer apparent with inverted faces. Therefore, it is likely that infantsâ enhanced attention to fear in our study was indeed a response to emotions rather than a reaction to arbitrary low-level stimulus features. This finding indicates enhanced attention to fear at 5 months and underscores the need to find mechanisms that engender the development of emotion knowledge early in life
Visual Scanning of Males and Females in Infancy
This study addressed the development of attention to information that is socially relevant to adults by examining infants\u27 (n = 64) scanning patterns of male and female bodies. Infants exhibited systematic attention to regions associated with sex-related scanning by adults, with 3.5-and 6.5-month-olds looking longer at the torso of females than males and longer at the legs of males than females. However, this pattern of looking was not found when infants were tested on headless bodies in Experiment 2, which suggests that infants\u27 differential gaze pattern in Experiment 1 was not due to low-level stimulus features, such as clothing, and also indicates that facial/head information is necessary for infants to exhibit sex-specific scanning. We discuss implications for models of face and body knowledge development
NuSTAR observation of a minuscule microflare in a solar active region
We present X-ray imaging spectroscopy of one of the weakest active region (AR) microflares ever studied. The microflare occurred at âŒ11:04 UT on 2018 September 9 and we studied it using the Nuclear Spectroscopic Telescope ARray (NuSTAR) and the Solar Dynamic Observatory's Atmospheric Imaging Assembly (SDO/AIA). The microflare is observed clearly in 2.5-7 keV with NuSTAR and in Fe XVIII emission derived from the hotter component of the 94 Ă
SDO/AIA channel. We estimate the event to be three orders of magnitude lower than a GOES A class microflare with an energy of 1.1e26 erg. It reaches temperatures of 6.7 MK with an emission measure of 8.0e43 cm^â3. Non-thermal emission is not detected but we instead determine upper limits to such emission. We present the lowest thermal energy estimate for an AR microflare in literature, which is at the lower limits of what is still considered an X-ray microflare
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