1,836 research outputs found
Lexical stress information modulates the time-course of spoken-word recognition
Segmental as well as suprasegmental information is used by Dutch listeners to recognize words. The time-course of the effect of suprasegmental stress information on spoken-word recognition was investigated in a previous study, in which we tracked Dutch listeners' looks to arrays of four printed words as they listened to spoken sentences. Each target was displayed along with a competitor that did not differ segmentally in its first two syllables but differed in stress placement (e.g., 'CENtimeter' and 'sentiMENT'). The listeners' eye-movements showed that stress information is used to recognize the target before distinct segmental information is available. Here, we examine the role of durational information in this effect. Two experiments showed that initial-syllable duration, as a cue to lexical stress, is not interpreted dependent on the speaking rate of the preceding carrier sentence. This still held when other stress cues like pitch and amplitude were removed. Rather, the speaking rate of the preceding carrier affected the speed of word recognition globally, even though the rate of the target itself was not altered. Stress information modulated lexical competition, but did so independently of the rate of the preceding carrier, even if duration was the only stress cue present
Rushing to Overpay: The REIT Premium Revisited
We explore the questions of whether and why Real Estate Investment Trusts (REITs) pay more for real estate than non-REIT buyers, consequently breaking the law of one price. We develop a model where REITs optimally pay more for property because (1) they are able, due to capital access advantages and, (2) are occasionally compelled, due to regulatory time constraints on the deployment of capital. We show that the typically large (20 to 60 percent) and statistically significant (p-values less than 0.01) REIT-buyer premiums found in standard empirical hedonic pricing models are biased due to unobserved explanatory variables. Using a repeat-transaction methodology that controls for unobserved independent variables, we find the REIT-buyer premium to be about 5 percent. Furthermore, we show that REITs¿ ability (as measured by access to capital markets) and regulator compulsion (as measured by capital deployment deadlines) are related to the price premium.Real Estate Investment Trusts (REITs), commercial properties, hedonic price analysis, repeat transactions, market efficiency, law of one price, price premium
A Cu2+ (S = 1/2) Kagom\'e Antiferromagnet: MgxCu4-x(OH)6Cl2
Spin-frustrated systems are one avenue for inducing macroscopic quantum
states in materials. However, experimental realization of this goal has been
difficult because of the lack of simple materials and, if available, the
separation of the unusual magnetic properties arising from exotic magnetic
states from behavior associated with chemical disorder, such as site mixing.
Here we report the synthesis and magnetic properties of a new series of
magnetically frustrated materials, MgxCu4-x(OH)6Cl2. Because of the
substantially different ligand-field chemistry of Mg2+ and Cu2+, site disorder
within the kagom\'e layers is minimized, as directly measured by X-ray
diffraction. Our results reveal that many of the properties of these materials
and related systems are not due to disorder of the magnetic lattice but rather
reflect an unusual ground state.Comment: Accepted for publication in J. Am. Chem. Soc
Tuning the Charge Density Wave and Superconductivity in CuxTaS2
We report the characterization of layered, 2H-type CuxTaS2, for x between 0
and 0.12. The charge density wave (CDW), at 70 K for TaS2, is destabilized with
Cu doping. The sub-1K superconducting transition in undoped 2H-TaS2 jumps
quickly to 2.5 K at low x, increases to 4.5 K at the optimal composition
Cu0.04TaS2, and then decreases at higher x. The electronic contribution to the
specific heat, first increasing and then decreasing as a function of Cu
content, is 12 mJ mol-1 K-2 at Cu0.04TaS2. Electron diffraction studies show
that the CDW remains present at the optimal superconducting composition, but
with both a changed q vector and decreased coherence length. We present an
electronic phase diagram for the system.Comment: 7 pages, 9 figures. To be published in Physical Review
Non-uniform carrier density in CdAs evidenced by optical spectroscopy
We report the detailed optical properties of CdAs crystals in a wide
parameter space: temperature, magnetic field, carrier concentration and crystal
orientation. We investigate high-quality crystals synthesized by three
different techniques. In all the studied samples, independently of how they
were prepared and how they were treated before the optical experiments, our
data indicate conspicuous fluctuations in the carrier density (up to 30%).
These charge puddles have a characteristic scale of 100 m, they become
more pronounced at low temperatures, and possibly, they become enhanced by the
presence of crystal twinning. The Drude response is characterized by very small
scattering rates ( meV) for as-grown samples. Mechanical treatment,
such as cutting or polishing, influences the optical properties of single
crystals, by increasing the Drude scattering rate and also modifying the high
frequency optical response. Magneto-reflectivity and Kerr rotation are
consistent with electron-like charge carriers and a spatially non-uniform
carrier density.Comment: Accepted in Physical Review
Variability of ethics education in laboratory medicine training programs: Results of an international survey.
To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files.
This article is open access.Ethical considerations are increasingly important in medicine. We aimed to determine the mode and extent of teaching of ethics in training programs in clinical chemistry and laboratory medicine.We developed an on-line survey of teaching in areas of ethics relevant to laboratory medicine. Reponses were invited from directors of training programs who were recruited via email to leaders of national organizations.The survey was completed by 80 directors from 24 countries who directed 113 programs. The largest numbers of respondents directed postdoctoral training of scientists (42%) or physicians (33%), post-masters degree programs (33%), and PhD programs (29%). Most programs (82%) were 2years or longer in duration. Formal training was offered in research ethics by 39%, medical ethics by 31%, professional ethics by 24% and business ethics by 9%. The number of reported hours of formal training varied widely, e.g., from 0 to >15h/year for research ethics and from 0 to >15h for medical ethics. Ethics training was required and/or tested in 75% of programs that offered training. A majority (54%) of respondents reported plans to add or enhance training in ethics; many indicated a desire for online resources related to ethics, especially resources with self-assessment tools.Formal teaching of ethics is absent from many training programs in clinical chemistry and laboratory medicine, with heterogeneity in the extent and methods of ethics training among the programs that provide the training. A perceived need exists for online training tools, especially tools with self-assessment components
Field-dependent heat transport in the Kondo insulator SmB6 : phonons scattered by magnetic impurities
The thermal conductivity of the Kondo insulator SmB was measured
at low temperature, down to 70 mK, in magnetic fields up to 15 T, on single
crystals grown using both the floating-zone and the flux methods. The residual
linear term at is found to be zero in all samples, for
all magnetic fields, in agreement with previous studies. There is therefore no
clear evidence of fermionic heat carriers. In contrast to some prior data, we
observe a large enhancement of with increasing field. The effect of
field is anisotropic, depending on the relative orientation of field and heat
current (parallel or perpendicular), and with respect to the cubic crystal
structure. We interpret our data in terms of heat transport predominantly by
phonons, which are scattered by magnetic impurities.Comment: publish versio
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Segmentation of British Sign Language (BSL): Mind the gap!
This study asks how users of British Sign Language (BSL) recognize individual signs in connected sign sequences. We examined whether this is achieved through modality-specific or modality-general segmentation procedures. A modality-specific feature of signed languages is that, during continuous signing, there are salient transitions between sign locations. We used the sign-spotting task to ask if and how BSL signers use these transitions in segmentation. A total of 96 real BSL signs were preceded by nonsense signs which were produced in either the target location or another location (with a small or large transition). Half of the transitions were within the same major body area (e.g., head) and half were across body areas (e.g., chest to hand). Deaf adult BSL users (a group of natives and early learners, and a group of late learners) spotted target signs best when there was a minimal transition and worst when there was a large transition. When location changes were present, both groups performed better when transitions were to a different body area than when they were within the same area. These findings suggest that transitions do not provide explicit sign-boundary cues in a modality-specific fashion. Instead, we argue that smaller transitions help recognition in a modality-general way by limiting lexical search to signs within location neighbourhoods, and that transitions across body areas also aid segmentation in a modality-general way, by providing a phonotactic cue to a sign boundary. We propose that sign segmentation is based on modality-general procedures which are core language-processing mechanisms
Charge density wave behavior and order-disorder in the antiferromagnetic metallic series Eu(Ga_1-xAl_x)_4
The solid solution Eu(Ga_1-xAl_x)_4 was grown in single crystal form to
reveal a rich variety of crystallographic, magnetic, and electronic properties
that differ from the isostructural end compounds EuGa_4 and EuAl_4, despite the
similar covalent radii and electronic configurations of Ga and Al. Here we
report the onset of magnetic spin reorientation and metamagnetic transitions
for x = 0 - 1 evidenced by magnetization and temperature-dependent specific
heat measurements. T_N changes non-monotonously with x, and it reaches a
maximum around 20 K for x = 0.50, where the a lattice parameter also shows an
extreme (minimum) value. Anomalies in the temperature-dependent resistivity
consistent with charge density wave behavior exist for x = 0.50 and 1 only.
Density functional theory calculations show increased polarization between the
Ga-Al covalent bonds in the x = 0.50 structure compared to the end compounds,
such that crystallographic order and chemical pressure are proposed as the
causes of the charge density wave behavior
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