327 research outputs found
The Communication of Metacognition for Social Strategy in Psychosis: An Exploratory Study
Sharing privately held information, for example, one’s confidence in the likelihood of future events, can greatly help others make better decisions as well as promoting one’s reputation and social influence. Differences in metacognition on the one hand, and difficulties in social functioning and social cognition on the other, have been reported in people diagnosed with schizophrenia and bipolar disorder. However, despite clear relevance few studies have investigated the link between these abilities and psychosis. In this exploratory study, we compared individuals diagnosed with schizophrenia, bipolar disorder, and a group of unselected general population controls, in an online competitive advice-giving task. Participants gave advice to a client by making a probabilistic perceptual judgment. They could strategically adapt the advice confidence to gain influence over the client. Crucially, participants competed with a rival adviser to attract the client’s endorsement. We observe that participants diagnosed with schizophrenia displayed an overall overconfidence in their advice compared with other, bipolar, and unselected control groups, but did not differ in metacognitive efficiency from controls. Symptom-based analysis revealed that the social-influence effect was associated with the presence of delusions but not hallucinations or mood symptoms. These results suggest that the social communication of uncertainty should be further investigated in psychosis
Frame Indifferent Formulation of Maxwell's Elastic Fluid and the Rational Continuum Mechanics of the Electromagnetic Field
We show that the linearized equations of the incompressible elastic medium
admit a `Maxwell form' in which the shear component of the stress vector plays
the role of the electric field, and the vorticity plays the role of the
magnetic field. Conversely, the set of dynamic Maxwell equations are strict
mathematical corollaries from the governing equations of the incompressible
elastic medium. This suggests that the nature of `electromagnetic field' may
actually be related to an elastic continuous medium. The analogy is complete if
the medium is assumed to behave as fluid in shear motions, while it may still
behave as elastic solid under compressional motions. Then the governing
equations of the elastic fluid are re-derived in the Eulerian frame by
replacing the partial time derivatives by the properly invariant (frame
indifferent) time rates. The `Maxwell from' of the frame indifferent
formulation gives the frame indifferent system that is to replace the Maxwell
system. This new system comprises terms already present in the classical
Maxwell equations, alongside terms that are the progenitors of the
Biot--Savart, Oersted--Ampere's, and Lorentz--force laws. Thus a frame
indifferent (truly covariant) formulation of electromagnetism is achieved from
a single postulate that the electromagnetic field is a kind of elastic (partly
liquid partly solid) continuum.Comment: accepte
Reptilia, Squamata, Gymnophthalmidae, Potamites apodemus (Uzzell, 1966): distribution extension and first records from Panama
Reporting on the southernmost locality in Costa Rica and the first two localities in Panama, we extend the known geographic distribution of the lizard Potamites apodemus (Uzzell, 1966) roughly 20 km eastwards, 40 km southwards, and 175 m in elevation. We provide photos of Panamanian specimens, comment on their morphology, and map the distribution of this unique species
Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph
The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT
in the spring of 2004. A pair of high-speed six-axis robots move the 300 fiber
buttons between observing configurations within ~300 s and to an accuracy ~25
microns. The optical fibers run for 26 m between the MMT's focal surface and
the bench spectrograph operating at R~1000-2000. Another high dispersion bench
spectrograph offering R~5,000, Hectochelle, is also available. The system
throughput, including all losses in the telescope optics, fibers, and
spectrograph peaks at ~10% at the grating blaze in 1" FWHM seeing. Correcting
for aperture losses at the 1.5" diameter fiber entrance aperture, the system
throughput peaks at 17%. Hectospec has proven to be a workhorse
instrument at the MMT. Hectospec and Hectochelle together were scheduled for
1/3 of the available nights since its commissioning. Hectospec has returned
\~60,000 reduced spectra for 16 scientific programs during its first year of
operation.Comment: 68 pages, 28 figures, to appear in December 2005 PAS
A parsimonious explanation for intersecting perinatal mortality curves: understanding the effect of plurality and of parity
BACKGROUND: Birth weight- and gestational age-specific perinatal mortality curves intersect when compared across categories of maternal smoking, plurality, race and other factors. No simple explanation exists for this paradoxical observation. METHODS: We used data on all live births, stillbirths and infant deaths in Canada (1991–1997) to compare perinatal mortality rates among singleton and twin births, and among singleton births to nulliparous and parous women. Birth weight- and gestational age-specific perinatal mortality rates were first calculated by dividing the number of perinatal deaths at any given birth weight or gestational age by the number of total births at that birth weight or gestational age (conventional calculation). Gestational age-specific perinatal mortality rates were also calculated using the number of fetuses at risk of perinatal death at any given gestational age. RESULTS: Conventional perinatal mortality rates among twin births were lower than those among singletons at lower birth weights and earlier gestation ages, while the reverse was true at higher birth weights and later gestational ages. When perinatal mortality rates were based on fetuses at risk, however, twin births had consistently higher mortality rates than singletons at all gestational ages. A similar pattern emerged in contrasts of gestational age-specific perinatal mortality among singleton births to nulliparous and parous women. Increases in gestational age-specific rates of growth-restriction with advancing gestational age presaged rising rates of gestational age-specific perinatal mortality in both contrasts. CONCLUSIONS: The proper conceptualization of perinatal risk eliminates the mortality crossover paradox and provides new insights into perinatal health issues
Semi-Holographic Fermi Liquids
We show that the universal physics of recent holographic non-Fermi liquid
models is captured by a semi-holographic description, in which a dynamical
boundary field is coupled to a strongly coupled conformal sector having a
gravity dual. This allows various generalizations, such as a dynamical exponent
and lattice and impurity effects. We examine possible relevant deformations,
including multi-trace terms and spin-orbit effects. We discuss the matching
onto the UV theory of the earlier work, and an alternate description in which
the boundary field is integrated out.Comment: 26 pages, 4 figures; v2: typos corrected and report number adde
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