254 research outputs found
Memory Modulation in the Classroom: Selective Enhancement of College Examination Performance by Arousal Induced after Lecture
Laboratory studies examining moderate physiological or emotional arousal induced after learning indicate that it enhances memory consolidation. Yet, no studies have yet examined this effect in an applied context. As such, arousal was induced after a college lecture and its selective effects were examined on later exam performance. Participants were divided into two groups who either watched a neutral video clip (n = 66) or an arousing video clip (n = 70) after lecture in a psychology course. The final examination occurred two weeks after the experimental manipulation. Only performance on the group of final exam items that covered material from the manipulated lecture were significantly different between groups. Other metrics, such as the midterm examination and the total final examination score, did not differ between groups. The results indicate that post-lecture arousal selectively increased the later retrieval of lecture material, despite the availability of the material for study before and after the manipulation. The results reinforce the role of post-learning arousal on memory consolidation processes, expanding the literature to include a real-world learning context
Muscle Tension Induced after Learning Enhances Long-Term Narrative and Visual Memory in Healthy Older Adults
Arousing events are better remembered than mundane events. Indeed, manipulation of arousal, such as by muscle tension, can influence memory even when it occurs shortly after learning. Indeed, our founding study showed this approach can raise delayed memory performance in older adults to a level comparable to that of unaided young adults. Yet, systematic studies, especially those investigating different modalities or types of memory, have not been done. This study investigated the effects of a brief bout of isometric exercise via handgrip on narrative and visuospatial episodic memory in healthy elders. Forty-seven participants completed the Logical Memory subtest of the Wechsler Memory Scales III (LM) and the Benton Visual Retention Test (BVRT), followed alternately by no treatment and by moderately squeezing a sand-filled latex ball for 1-min (counterbalanced order and test forms). Isometric exercise significantly increased both positive and negative affect ratings. Retention was tested 2 weeks later. Delayed recall and recognition of LM was enhanced by arousal relative to control, as was recognition of the BVRT. The results extend past findings that muscle tension induced after learning modulates memory consolidation, extending findings in elders to suggest that a simple form of isometric exercise can have practical effects, such as aiding memory for stories and images
The Pristine Inner Galaxy Survey (PIGS) VII: a discovery of the first inner Galaxy CEMP-r/s star
Well-studied very metal-poor (VMP, [Fe/H] < -2 ) stars in the inner Galaxy
are few in number, and they are of special interest because they are expected
to be among the oldest stars in the MilkyWay. We present high-resolution
spectroscopic follow-up of the carbon-enhanced metal-poor (CEMP) star
Pristine_184237.56-260624.5 (hereafter Pr184237) identified in the Pristine
Inner Galaxy Survey. This star has an apocentre of about 2 kpc. Its atmospheric
parameters (Teff = 5100 K, log g = 2.0, [Fe/H] = -2.60) were derived based on
the non-local thermodynamic equilibrium (NLTE) line formation. We determined
abundances for 32 elements, including 15 heavy elements beyond the iron group.
The NLTE abundances were calculated for 13 elements from Na to Pb. Pr184237 is
strongly enhanced in C, N, O, and both s- and r-process elements from Ba to Pb;
it reveals a low carbon isotope ratio of 12C/13C = 7. The element abundance
pattern in the Na-Zn range is typical of halo stars. With [Ba/Eu] = 0.32,
Pr184237 is the first star of the CEMP-r/s subclass identified in the inner
Galaxy. Variations in radial velocity suggest binarity. We tested whether a
pollution by the s- or i-process material produced in the more massive and
evolved companion can form the observed abundance pattern and find that an
i-process in the asymptotic giant branch star with a progenitor mass of 1.0-2.0
Msun can be the solution.Comment: 15 pages, 11 figures, 5 tables, MNRAS, accepte
4MOST Consortium Survey 3: Milky Way Disc and Bulge Low-Resolution Survey (4MIDABLE-LR)
The mechanisms of the formation and evolution of the Milky Way are encoded in
the orbits, chemistry and ages of its stars. With the 4MOST MIlky way Disk And
BuLgE Low-Resolution Survey (4MIDABLE-LR) we aim to study kinematic and
chemical substructures in the Milky Way disc and bulge region with samples of
unprecedented size out to larger distances and greater precision than
conceivable with Gaia alone or any other ongoing or planned survey. Gaia gives
us the unique opportunity for target selection based almost entirely on
parallax and magnitude range, hence increasing the efficiency in sampling
larger Milky Way volumes with well-defined and effective selection functions.
Our main goal is to provide a detailed chrono-chemo-kinematical extended map of
our Galaxy and the largest Gaia follow-up down to magnitudes (Vega).
The complex nature of the disc components (for example, large target densities
and highly structured extinction distribution in the Milky Way bulge and disc
area), prompted us to develop a survey strategy with five main sub-surveys that
are tailored to answer the still open questions about the assembly and
evolution of our Galaxy, while taking full advantage of the Gaia data.Comment: Part of the 4MOST issue of The Messenger, published in preparation of
4MOST Community Workshop, see http://www.eso.org/sci/meetings/2019/4MOST.htm
Modelling simple stellar populations in the near-ultraviolet to near-infrared with the X-shooter Spectral Library (XSL)
We present simple stellar population models based on the empirical X-shooter
Spectral Library (XSL) from NUV to NIR wavelengths. The unmatched
characteristics of relatively high resolution and extended wavelength coverage
( nm, ) of the XSL population models bring us closer to
bridging optical and NIR studies of intermediate and old stellar populations.
It is now common to find good agreement between observed and predicted NUV and
optical properties of stellar clusters due to our good understanding of the
main-sequence and early giant phases of stars. However, NIR spectra of
intermediate-age and old stellar populations are sensitive to cool K and M
giants. The asymptotic giant branch, especially the thermally pulsing
asymptotic giant branch, shapes the NIR spectra of Gyr old stellar
populations; the tip of the red giant branch defines the NIR spectra of
populations with ages larger than that. We construct sequences of the average
spectra of static giants, variable-rich giants, and C-rich giants to include in
the models separately. The models span the metallicity range
and ages above 50 Myr, a broader range in the NIR than in other models based on
empirical spectral libraries. Our models can reproduce the integrated optical
colours of the Coma cluster galaxies at the same level as other semi-empirical
models found in the literature. In the NIR, there are notable differences
between the colours of the models and Coma cluster galaxies. The XSL models
expand the range of predicted values of NIR indices compared to other models
based on empirical libraries. Our models make it possible to perform in-depth
studies of colours and spectral features consistently throughout the optical
and the NIR range to clarify the role of evolved cool stars in stellar
populations.Comment: 30 pages, 26 figures, accepted to Astronomy & Astrophysics, models
will be available on http://xsl.astro.unistra.fr/ upon publishin
Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?
The most metal-poor stars (e.g. [Fe/H] ) are the ancient fossils
from the early assembly epoch of our Galaxy, very likely before the formation
of the thick disc. Recent studies have shown that a non-negligible fraction of
them have prograde planar orbits, which makes their origin a puzzle. It has
been suggested that a later-formed rotating bar could have driven these old
stars from the inner Galaxy outward, and transformed their orbits to be more
rotation-dominated. However, it is not clear if this mechanism can explain
these stars as observed in the solar neighborhood. In this paper, we explore
the possibility of this scenario by tracing these stars backwards in an
axisymmetric Milky Way potential with a bar perturber. We integrate their
orbits backward for 6 Gyr under two bar models: one with a constant pattern
speed and another one with a decelerating speed. Our experiments show that,
under the constantly-rotating bar model, the stars of interest are little
affected by the bar and cannot have been shepherded from a spheroidal inner
Milky Way to their current orbits. In the extreme case of a rapidly
decelerating bar, some of the very metal-poor stars on planar and prograde
orbits can be brought from the inner Milky Way, but of them were
nevertheless already rotation-dominated ( 1000 km s
kpc) 6 Gyr ago. The chance of these stars having started with spheroid-like
orbits with small rotation ( 600 km s kpc) is very
low ( 3). We therefore conclude that, within the solar neighborhood, the
bar is unlikely to have shepherded a significant fraction of inner Galaxy
spheroid stars to produce the overdensity of stars on prograde, planar orbits
that is observed today.Comment: submitted to A&A, comments are welcom
The X-shooter Spectral Library (XSL): Data Release 3
We present the third data release (DR3) of the X-shooter Spectral Library
(XSL). This moderate-to-high resolution, near-ultraviolet-to-near-infrared
( nm, R 10 000) spectral library is composed of 830 stellar
spectra of 683 stars. DR3 improves upon the previous data release by providing
the combined de-reddened spectra of the three X-shooter segments over the full
nm wavelength range. It also includes additional 20 M-dwarf spectra
from the ESO archive. We provide detailed comparisons between this library and
Gaia EDR3, MILES, NGSL, CaT library, and (E-)IRTF. The normalised rms deviation
is better than or 5 for the majority of spectra in common between
MILES (144 spectra of 180), NGSL (112116), and (E-)IRTF (5577) libraries.
Comparing synthetic colours of those spectra reveals only negligible offsets
and small rms scatter, such as the median offset(rms) 0.0010.040 mag in
the (box1-box2) colour of the UVB arm,-0.0040.028 mag in (box3-box4) of
the VIS arm, and -0.0010.045 mag in (box2-box3) colour between the UVB and
VIS arms, when comparing stars in common with MILES. We also find an excellent
agreement between the Gaia published (BP-RP) colours and those measured from
the XSL DR3 spectra, with a zero median offset and an rms scatter of 0.037 mag
for 449 non-variable stars. The unmatched characteristics of this library,
which combine a relatively high resolution, a large number of stars, and an
extended wavelength coverage, will help us to bridge the gap between the
optical and the near-IR studies of intermediate and old stellar populations,
and to probe low-mass stellar systems.Comment: 26 pages, 25 figures, accepted to Astronomy & Astrophysics. The data
are available at the CDS via anonymous ftp to
cdsarc.u-strasbg.fr(130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ or on the XSL web-page
http://xsl.astro.unistra.f
Modelling acquired resistance to DOT1L inhibition exhibits the adaptive potential of KMT2A-rearranged acute lymphoblastic leukemia
In KMT2A-rearranged acute lymphoblastic leukemia (ALL), an aggressive malignancy, oncogenic KMT2A-fusion proteins inappropriately recruit DOT1L to promote leukemogenesis, highlighting DOT1L as an attractive therapeutic target. Unfortunately, treatment with the first-in-class DOT1L inhibitor pinometostat eventually leads to non-responsiveness. To understand this we established acquired pinometostat resistance in pediatric KMT2A::AFF1+ B-ALL cells. Interestingly, these cells became mostly independent of DOT1L-mediated H3K79 methylation, but still relied on the physical presence of DOT1L, HOXA9 and the KMT2A::AFF1 fusion. Moreover, these cells selectively lost the epigenetic regulation and expression of various KMT2A-fusion target genes such as PROM1/CD133, while other KMT2A::AFF1 target genes, including HOXA9 and CDK6 remained unaffected. Concomitantly, these pinometostat-resistant cells showed upregulation of several myeloid-associated genes, including CD33 and LILRB4/CD85k. Taken together, this model comprehensively shows the adaptive potential of KMT2A-rearranged ALL cells upon losing dependency on one of its main oncogenic properties
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