396 research outputs found
Investigating the lexico-grammatical resources of a non-native user of English:The case of can and could in email requests
Individual users of English as a first or second language are assumed to possess or aspire to a monolithic grammar, an internally consistent set of rules which represents the idealized norms or conventions of native speakers. This position reflects a deficit view of L2 learning and usage, and is at odds with usage-based approaches to language development and research findings on idiolectal variation. This study problematizes the assumption of monolithic ontologies of grammar for TESOL by exploring a fragment of genre-specific lexico-grammatical knowledge (the can you/could you V construction alternation in requests) in a single non-native user of English, post-instruction. A corpus sample of the individual’s output was compared with the input he was exposed to and broader norms for the genre. The analysis confirms findings in usage-based linguistics which demonstrate that an individual’s lexico-grammatical knowledge constitutes an inventory of constructions shaped in large part by distributional patterns in the input. But it also provides evidence for idiosyncratic preferences resulting from exemplar-based inertia in production, suggesting that input is not the sole factor. Results are discussed in the context of a “plurilithic” ontology of grammar and the challenges this represents for pedagogy and teacher development
A Note on Fluxes and Superpotentials in M-theory Compactifications on Manifolds of G_2 Holonomy
We consider the breaking of N=1 supersymmetry by non-zero G-flux when
M-theory is compactified on a smooth manifold X of G_2 holonomy. Gukov has
proposed a superpotential W to describe this breaking in the low-energy
effective theory. We check this proposal by comparing the bosonic potential
implied by W with the corresponding potential deduced from the
eleven-dimensional supergravity action. One interesting aspect of this check is
that, though W depends explicitly only on G-flux supported on X, W also
describes the breaking of supersymmetry by G-flux transverse to X.Comment: 15 pages, harvmac, v2: reference adde
Opacity Effects on Pulsations of Main-Sequence A-Type Stars
Opacity enhancements for stellar interior conditions have been explored to
explain observed pulsation frequencies and to extend the pulsation instability
region for B-type main-sequence variable stars. For these stars, the pulsations
are driven in the region of the opacity bump of Fe-group elements at
200,000 K in the stellar envelope. Here we explore effects of opacity
enhancements for the somewhat cooler main-sequence A-type stars, in which
-mode pulsations are driven instead in the second helium ionization region
at 50,000 K. We compare models using the new LANL OPLIB vs. LLNL OPAL
opacities for the AGSS09 solar mixture. For models of 2 solar masses and
effective temperature 7600 K, opacity enhancements have only a mild effect on
pulsations, shifting mode frequencies and/or slightly changing kinetic-energy
growth rates. Increased opacity near the bump at 200,000 K can induce
convection that may alter composition gradients created by diffusive settling
and radiative levitation. Opacity increases around the hydrogen and 1st He
ionization region (13,000 K) can cause additional higher-frequency modes to
be excited, raising the possibility that improved treatment of these layers may
result in prediction of new modes that could be tested by observations. New or
wider convective zones and higher convective velocities produced by opacity
increases could also affect angular momentum transport during evolution. More
work needs to be done to quantify the effects of opacity on the boundaries of
the pulsation instability regions for A-type stars.Comment: 14 pages, 12 figures. Accepted version for MDPI Atoms Special Issue
"Atomic and Molecular Opacity Data for Astrophysics", Published 4 June 2018,
Atoms 2018, 6(2), 31, https://doi.org/10.3390/atoms602003
A First Principles Theory of Nuclear Magnetic Resonance J-Coupling in solid-state systems
A method to calculate NMR J-coupling constants from first principles in
extended systems is presented. It is based on density functional theory and is
formulated within a planewave-pseudopotential framework. The all-electron
properties are recovered using the projector augmented wave approach. The
method is validated by comparison with existing quantum chemical calculations
of solution-state systems and with experimental data. The approach has been
applied to verify measured J-coupling in a silicophosphate structure,
Si5O(PO4)6Comment: 9 page
Global offtake of wild animals from wetlands: critical issues for fish and birds
The global offtake of wild animals is valued at US$400 billion annually and supports the livelihoods of 15% of the global population. Wetlands are amongst the most important ecosystems globally, but offtake may represent a substantial pressure. This study assessed the availability of information and evaluated the offtake of wild animals from wetlands by focussing on fish and waterbirds. A literature search identified 2726 studies on wetland offtake. Scoping of these resulted in 82 studies that contained quantitative information on fish or waterbird offtake. Fishing offtake statistics for inland waters are collated nationally by some governments, but other sources of information are few. Reporting of fish offtake for species or across scales was constrained by insufficient detail, even in relatively well-documented countries such as Bangladesh. Although government hunting statistics from Europe and North America were available, there was little waterbird data from less economically developed countries. The case of Canada indicated that the species richness and composition of waterbirds taken varied between indigenous subsistence and recreational hunting communities. Hidden (unquantified) offtake, of both fish and waterbirds, hinders obtaining precise data for offtake, which may threaten the conservation of species and the sustainability of wetland ecosystems
Prediction of hospital outcome in septic shock: a prospective comparison of tissue Doppler and cardiac biomarkers
Introduction: Diastolic dysfunction as demonstrated by tissue Doppler imaging (TDI), particularly E/e' (peak early diastolic transmitral/peak early diastolic mitral annular velocity) is common in critical illness. In septic shock, the prognostic value of TDI is undefined. This study sought to evaluate and compare the prognostic significance of TDI and cardiac biomarkers (B-type natriuretic peptide (BNP); N-terminal proBNP (NTproBNP); troponin T (TnT)) in septic shock. The contribution of fluid management and diastolic dysfunction to elevation of BNP was also evaluated
The influence of music on mood and performance while driving
Mood can influence our everyday behaviour and people often seek to reinforce, or to alter their mood, for example by turning on music. Music listening while driving is a popular activity. However, little is known about the impact of music listening while driving on physiological state and driving performance. In the present experiment, it was investigated whether individually selected music can induce mood and maintain moods during a simulated drive. In addition, effects of positive, negative, and no music on driving behaviour and physiological measures were assessed for normal and high cognitive demanding rides. Subjective mood ratings indicated that music successfully maintained mood while driving. Narrow lane width drives increased task demand as shown in effort ratings and increased swerving. Furthermore, respiration rate was lower during music listening compared to rides without music, while no effects of music were found on heart rate. Overall, the current study demonstrates that music listening in car influences the experienced mood while driving, which in turn can impact driving behaviour. Practitioners Summary: Even though it is a popular activity, little is known about the impact of music while driving on physiological state and performance. We examined whether music can induce moods during high and low simulated drives. The current study demonstrates that in car music listening influences mood which in turn can impact driving behaviour. The current study shows that listening to music can positively impact mood while driving, which can be used to affect state and safe behaviour. Additionally, driving performance in high demand situations is not negatively affected by music
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