1,509 research outputs found
The impact of second language learning on semantic and nonsemantic first language reading
The relationship between orthography (spelling) and phonology
(speech sounds) varies across alphabetic languages. Consequently,
learning to read a second alphabetic language, that uses the same
letters as the first, increases the phonological associations that can
be linked to the same orthographic units. In subjects with English
as their first language, previous functional imaging studies have
reported increased left ventral prefrontal activation for reading
words with spellings that are inconsistent with their orthographic
neighbors (e.g., PINT) compared with words that are consistent
with their orthographic neighbors (e.g., SHIP). Here, using
functional magnetic resonance imaging (fMRI) in 17 Italian--English
and 13 English--Italian bilinguals, we demonstrate that left ventral
prefrontal activation for first language reading increases with
second language vocabulary knowledge. This suggests that
learning a second alphabetic language changes the way that
words are read in the first alphabetic language. Specifically, first
language reading is more reliant on both lexical/semantic and
nonlexical processing when new orthographic to phonological
mappings are introduced by second language learning. Our
observations were in a context that required participants to switch
between languages. They motivate future fMRI studies to test
whether first language reading is also altered in contexts when the
second language is not in use
The role of the left head of caudate in suppressing irrelevant words
Suppressing irrelevant words is essential to successful speech production and is expected to involve general control mechanisms that reduce interference from task-unrelated processing. To investigate the neural mechanisms that suppress visual word interference, we used fMRI and a Stroop task, using a block design with an event-related analysis. Participants indicated with a finger press whether a visual stimulus was colored pink or blue. The stimulus was either the written word "BLUE," the written word "PINK," or a string of four Xs, with word interference introduced when the meaning of the word and its color were "incongruent" (e.g., BLUE in pink hue) relative to congruent (e.g., BLUE in blue) or neutral (e.g., XXXX in pink). The participants also made color decisions in the presence of spatial interference rather than word interference (i.e., the Simon task). By blocking incongruent, congruent, and neutral trials, we identified activation related to the mechanisms that suppress interference as that which was greater at the end relative to the start of incongruency. This highlighted the role of the left head of caudate in the control of word interference but not spatial interference. The response in the left head of caudate contrasted to bilateral inferior frontal activation that was greater at the start than at the end of incongruency, and to the dorsal anterior cingulate gyrus which responded to a change in the motor response. Our study therefore provides novel insights into the role of the left head of caudate in the mechanisms that suppress word interference
Antiproton-deuteron annihilation at low energies
Recent experimental studies of the antiproton-deuteron system at low energies
have shown that the imaginary part of the antiproton-deuteron scattering length
is smaller than the antiproton-proton one. Two- and three-body systems with
strong annihilation are investigated and a mechanism explaining this unexpected
relation between the imaginary parts of the scattering lengths is proposed.Comment: 6 pages, 3 figures, to be published in The European Physical Journal
Predictors of Prescription Opioid Misuse Based on Type of Healthcare Insurance
The misuse and abuse of prescription opioid (PO) medications has garnered the attention of lawmakers, healthcare professionals, and public health experts since the opioid epidemic was declared a national public health emergency in 2017. Our purpose in this study was to investigate the types of healthcare insurance that predict PO misuse. We also sought to inform stakeholders of potentially needed changes to the existing inconsistent drug utilization rules necessary to achieve parity among all types of healthcare insurance and minimize loopholes. We performed a secondary data analysis on the 2019 National Survey on Drug Use and Health data of noninstitutionalized U.S. citizens aged 12 years and older and used a binary logistic regression analysis to evaluate the data. Medicare beneficiaries were 1.79 times more likely and those who had private healthcare insurance through an employer or union were 1.68 times more likely (95% CI [ 1.025, 3.141] and [1.148, 2.463], respectively) than respondents with other healthcare insurances to use PO longer or in greater amounts than the prescription intended. Respondents who had Medicare were 2.226 times more likely than respondents with other healthcare insurance (95% CI [1.029, 4.989]) to misuse PO by taking the medications longer and for other reasons not specified. Our study demonstrates that the type of healthcare insurance is a predictor of PO misuse. Our research also emphasizes the need for stakeholders to use evidence-based research to ensure parity among insurances
Expression of Lamin A/C in early-stage breast cancer and its prognostic value
Purpose: Lamins A/C, a major component of the nuclear lamina, plays key roles in maintaining nuclear integrity, regulation of gene expression, cell proliferation and apoptosis. Reduced lamin A/C expression in cancer has been reported to be a sign of poor prognosis. However, its clinical significance in breast cancer remains to be defined. This study aimed to evaluate expression and prognostic significance of lamin A/C in early-stage breast cancer.Methods: Using immunohistochemical staining of tissue microarrays, expression of lamin A/C was evaluated in a large well-characterised series of early-stage operable breast cancer (n=938) obtained from Nottingham Primary Breast Carcinoma Series. Association of lamin A/C expression with clinicopathological parameters and outcome was evaluated.Results: Positive expression rate of lamin A/C in breast cancer was 42.2% (n=398). Reduced/loss of expression of lamin A/C was significantly associated with high histological grade (p [less than] 0.001), larger tumour size (p=0.004), poor Nottingham Prognostic Index (NPI) score (p [less than] 0.001), lymphovascular invasion (p=0.014) and development of distant metastasis (p=0.027). Survival analysis showed that reduced/loss of expression of lamin A/C was significantly associated with shorter breast cancer specific survival (p=0.008).Conclusion: This study suggests lamin A/C plays a role in breast cancer and loss of its expression is associated with variables of poor prognosis and shorter outcome
Singular Liouville fields and spiky strings in \rr^{1,2} and SL(2,\rr)
The closed string dynamics in \rr^{1,2} and SL(2,\rr) is studied within
the scheme of Pohlmeyer reduction. In both spaces two different classes of
string surfaces are specified by the structure of the fundamental quadratic
forms. The first class in \rr^{1,2} is associated with the standard lightcone
gauge strings and the second class describes spiky strings and their conformal
deformations on the Virasoro coadjoint orbits. These orbits correspond to
singular Liouville fields with the monodromy matrixes . The first class
in SL(2,\rr) is parameterized by the Liouville fields with vanishing chiral
energy functional. Similarly to \rr^{1,2}, the second class in SL(2,\rr)
describes spiky strings, related to the vacuum configurations of the
SL(2,\rr)/U(1) coset model.Comment: 37 p. 6 fi
WIMP Annual Modulation with Opposite Phase in Late-Infall Halo Models
We show that in the late-infall model of our galactic halo by P. Sikivie the
expected phase of the annual modulation of a WIMP halo signal in direct
detection experiments is opposite to the one usually expected. If a
non-virialized halo component due to the infall of (collisionless) dark matter
particles cannot be rejected, an annual modulation in a dark matter signal
should be looked for by experimenters without fixing the phase a-priori.
Moreover, WIMP streams coming to Earth from directions above and below the
galactic plane should be expected, with a characteristic pattern of arrival
directions.Comment: 15 pages, 5 figure
Effect of halo modelling on WIMP exclusion limits
WIMP direct detection experiments are just reaching the sensitivity required
to detect galactic dark matter in the form of neutralinos. Data from these
experiments are usually analysed under the simplifying assumption that the
Milky Way halo is an isothermal sphere with maxwellian velocity distribution.
Observations and numerical simulations indicate that galaxy halos are in fact
triaxial and anisotropic. Furthermore, in the cold dark matter paradigm
galactic halos form via the merger of smaller subhalos, and at least some
residual substructure survives. We examine the effect of halo modelling on WIMP
exclusion limits, taking into account the detector response. Triaxial and
anisotropic halo models, with parameters motivated by observations and
numerical simulations, lead to significant changes which are different for
different experiments, while if the local WIMP distribution is dominated by
small scale clumps then the exclusion limits are changed dramatically.Comment: 9 pages, 9 figures, version to appear in Phys. Rev. D, minor change
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