5,109 research outputs found
A very brief introduction to quantum computing and quantum information theory for mathematicians
This is a very brief introduction to quantum computing and quantum
information theory, primarily aimed at geometers. Beyond basic definitions and
examples, I emphasize aspects of interest to geometers, especially connections
with asymptotic representation theory. Proofs of most statements can be found
in standard references
Depressive symptoms are associated with analgesic use in people with Alzheimer's disease: Kuopio ALSOVA study.
Neuropsychiatric symptoms of Alzheimer's disease (AD) such as depression may be associated with pain, which according to the literature may be inadequately recognized and managed in this population. This study aimed to identify the factors associated with analgesic use in persons with AD; in particular, how AD severity, functional status, neuropsychiatric symptoms of AD, co-morbidities and somatic symptoms are associated with analgesic use. 236 community-dwelling persons with very mild or mild AD at baseline, and their caregivers, were interviewed over five years as part of the prospective ALSOVA study. Generalized Estimating Equations (GEEs) were used to estimate unadjusted and adjusted odds ratios (ORs) for the factors associated with analgesic use over a five year follow-up. The proportion of persons with AD using any analgesic was low (13.6%) at baseline and remained relatively constant during the follow-up (15.3% at Year 5). Over time, the most prevalent analgesic changed from non-steroidal anti-inflammatories (8.1% of persons with AD at Year 1) to acetaminophen (11.1% at Year 5). Depressive symptoms (measured by the Beck Depression Inventory, BDI) were independently associated with analgesic use, after effects of age, gender, education, AD severity, comorbidities and somatic symptoms were taken into account. For every one unit increase in BDI, the odds of analgesic use increased by 4% (OR = 1.04, 95% confidence interval CI = 1.02-1.07). Caregiver depressive symptoms were not statistically significantly associated with analgesic use of the person with AD. Depressive symptoms were significantly associated with analgesic use during the five year follow-up period. Possible explanations warranting investigation are that persons with AD may express depressive symptoms as painful somatic complaints, or untreated pain may cause depressive symptoms. Greater awareness of the association between depressive symptoms and analgesic use may lead to safer and more effective prescribing for these conditions
An experimental test of non-local realism
Most working scientists hold fast to the concept of 'realism' - a viewpoint
according to which an external reality exists independent of observation. But
quantum physics has shattered some of our cornerstone beliefs. According to
Bell's theorem, any theory that is based on the joint assumption of realism and
locality (meaning that local events cannot be affected by actions in space-like
separated regions) is at variance with certain quantum predictions. Experiments
with entangled pairs of particles have amply confirmed these quantum
predictions, thus rendering local realistic theories untenable. Maintaining
realism as a fundamental concept would therefore necessitate the introduction
of 'spooky' actions that defy locality. Here we show by both theory and
experiment that a broad and rather reasonable class of such non-local realistic
theories is incompatible with experimentally observable quantum correlations.
In the experiment, we measure previously untested correlations between two
entangled photons, and show that these correlations violate an inequality
proposed by Leggett for non-local realistic theories. Our result suggests that
giving up the concept of locality is not sufficient to be consistent with
quantum experiments, unless certain intuitive features of realism are
abandoned.Comment: Minor corrections to the manuscript, the final inequality and all its
conclusions do not change; description of corrections (Corrigendum) added as
new Appendix III; Appendix II replaced by a shorter derivatio
A test of general relativity from the three-dimensional orbital geometry of a binary pulsar
Binary pulsars provide an excellent system for testing general relativity
because of their intrinsic rotational stability and the precision with which
radio observations can be used to determine their orbital dynamics.
Measurements of the rate of orbital decay of two pulsars have been shown to be
consistent with the emission of gravitational waves as predicted by general
relativity, providing the most convincing evidence for the self-consistency of
the theory to date. However, independent verification of the orbital geometry
in these systems was not possible. Such verification may be obtained by
determining the orientation of a binary pulsar system using only classical
geometric constraints, permitting an independent prediction of general
relativistic effects. Here we report high-precision timing of the nearby binary
millisecond pulsar PSR J0437-4715, which establish the three-dimensional
structure of its orbit. We see the expected retardation of the pulse signal
arising from the curvature of space-time in the vicinity of the companion
object (the `Shapiro delay'), and we determine the mass of the pulsar and its
white dwarf companion. Such mass determinations contribute to our understanding
of the origin and evolution of neutron stars.Comment: 5 pages, 2 figure
High Energy Cosmic Rays From Supernovae
Cosmic rays are charged relativistic particles that reach the Earth with
extremely high energies, providing striking evidence of the existence of
effective accelerators in the Universe. Below an energy around
eV cosmic rays are believed to be produced in the Milky Way while above that
energy their origin is probably extragalactic. In the early '30s supernovae
were already identified as possible sources for the Galactic component of
cosmic rays. After the '70s this idea has gained more and more credibility
thanks to the the development of the diffusive shock acceleration theory, which
provides a robust theoretical framework for particle energization in
astrophysical environments. Afterwards, mostly in recent years, much
observational evidence has been gathered in support of this framework,
converting a speculative idea in a real paradigm. In this Chapter the basic
pillars of this paradigm will be illustrated. This includes the acceleration
mechanism, the non linear effects produced by accelerated particles onto the
shock dynamics needed to reach the highest energies, the escape process from
the sources and the transportation of cosmic rays through the Galaxy. The
theoretical picture will be corroborated by discussing several observations
which support the idea that supernova remnants are effective cosmic ray
factories.Comment: Final draft of a chapter in "Handbook of Supernovae" edited by Athem
W. Alsabti and Paul Murdi
A computational proof of locality in entanglement
In this paper the design and proof of concept (POC) coding of a local hidden
variables computer model is presented. The program violates the Clauser, Horne,
Shimony and Holt inequality CHSH . In our numerical experiment,
we find with our local computer program, CHSH
How much contextuality?
The amount of contextuality is quantified in terms of the probability of the
necessary violations of noncontextual assignments to counterfactual elements of
physical reality.Comment: 5 pages, 3 figure
Digital chronofiles of life experience
Technology has brought us to the point where we are able to digitally sample life experience in rich multimedia detail, often referred to as lifelogging. In this paper we explore the potential of lifelogging for the digitisation and archiving of life experience into a longitudinal media archive for an individual. We motivate the historical archive potential for rich digital memories, enabling individuals’ digital footprints to con- tribute to societal memories, and propose a data framework to gather and organise the lifetime of the subject
Cognitive neuropsychiatric analysis of an additional large Capgras delusion case series
Introduction:: Although important to cognitive neuropsychiatry
and theories of delusions, Capgras delusion has largely been
reported in single case studies. Bell et al. [2017. Uncovering
Capgras delusion using a large scale medical records database.
British Journal of Psychiatry Open, 3(4), 179–185] previously
deployed computational and clinical case identification on a largescale medical records database to report a case series of 84
individuals with Capgras delusion. We replicated this approach on
a new database from a different mental health service provider
while additionally examining instances of violence, given previous
claims that Capgras is a forensic risk.
Methods:: We identified 34 additional cases of Capgras. Delusion
phenomenology, clinical characteristics, and presence of lesions
detected by neuroimaging were extracted.
Results:: Although most cases involved misidentification of family
members or partners, a notable minority (20.6%) included the
misidentification of others. Capgras typically did not present as a
monothematic delusion. Few cases had identifiable lesions with
no evidence of right-hemisphere bias. There was no evidence of
physical violence associated with Capgras.
Conclusions:: Findings closely replicate Bell et al. (2017). The
majority of Capgras delusion phenomenology conforms to the
“dual route” model although a significant minority of cases cannot
be explained by this framework
Entanglement Zoo II: Examples in Physics and Cognition
We have recently presented a general scheme enabling quantum modeling of
different types of situations that violate Bell's inequalities. In this paper,
we specify this scheme for a combination of two concepts. We work out a quantum
Hilbert space model where 'entangled measurements' occur in addition to the
expected 'entanglement between the component concepts', or 'state
entanglement'. We extend this result to a macroscopic physical entity, the
'connected vessels of water', which maximally violates Bell's inequalities. We
enlighten the structural and conceptual analogies between the cognitive and
physical situations which are both examples of a nonlocal non-marginal box
modeling in our classification.Comment: 11 page
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