3,402 research outputs found
Predicted Causality in Decision Making: The Role of Culture
In the wider sense, decision making is embedded in the problem-solving process and its many stages (Davidson and Sternberg, 2003; Güss et al., 2010). In the narrow sense, decision making is understood as the ability to select one of several alternatives and to act accordingly (Güss 2004). Previous research has often focused on decision making in relatively predictable environments with clear goals (e.g., expected utility theory of von Neumann and Morgenstern, 1944). In recent decades the focus has been on decision making heuristics, i.e., strategies or rules of thumb, applied in uncertain situations (e.g., Tversky and Kahneman, 1974; Simon, 1979; Gigerenzer and Gaissmaier, 2011).
Causality plays an important role in many cognitive processes – and causal cognition is itself influenced by culture (e.g., Norenzayan and Nisbett, 2000; Medin and Atran, 2004; Beller et al., 2009; Bender and Beller, 2011; for a controversial discussion of causal cognition, see Sperber et al., 1995). Causality is especially important during the decision-making process, because the decision maker has to predict what consequences specific decisions bring about before making a decision
Comment on 'A first map of tropical Africa's above-ground biomass derived from satellite imagery'
Copyright Institute of Physics © 2011We present a critical evaluation of the above-ground biomass (AGB) map of Africa published in this journal by Baccini et al (2008 Environ. Res. Lett. 3 045011). We first test their map against an independent dataset of 1154 scientific inventory plots from 16 African countries, and find only weak correspondence between our field plots and the AGB value given for the surrounding 1 km pixel by Baccini et al. Separating our field data using a continental landcover classification suggests that the Baccini et al map underestimates the AGB of forests and woodlands, while overestimating the AGB of savannas and grasslands. Secondly, we compare their map to 216 000 × 0.25 ha spaceborne LiDAR footprints. A comparison between Lorey's height (basal-area-weighted average height) derived from the LiDAR data for 1 km pixels containing at least five LiDAR footprints again does not support the hypothesis that the Baccini et al map is accurate, and suggests that it significantly underestimates the AGB of higher AGB areas. We conclude that this is due to the unsuitability of some of the field data used by Baccini et al to create their map, and overfitting in their model, resulting in low accuracies outside the small areas from which their field data are drawn
Abelian-Higgs and Vortices from ABJM: towards a string realization of AdS/CMT
We present ans\"{a}tze that reduce the mass-deformed ABJM model to gauged
Abelian scalar theories, using the fuzzy sphere matrices . One such
reduction gives a Toda system, for which we find a new type of nonabelian
vortex. Another gives the standard Abelian-Higgs model, thereby allowing us to
embed all the usual (multi-)vortex solutions of the latter into the ABJM model.
By turning off the mass deformation at the level of the reduced model, we can
also continuously deform to the massive theory in the massless ABJM
case. In this way we can embed the Landau-Ginzburg model into the AdS/CFT
correspondence as a consistent truncation of ABJM. In this context, the mass
deformation parameter and a field VEV act as and
respectively, leading to a well-motivated AdS/CMT construction from string
theory. To further this particular point, we propose a simple model for the
condensed matter field theory that leads to an approximate description for the
ABJM abelianization. Finally, we also find some BPS solutions to the
mass-deformed ABJM model with a spacetime interpretation as an M2-brane ending
on a spherical M5-brane.Comment: 43 pages, latex, explanations added in the introduction, end of
section 4, and on page 2
A soliton menagerie in AdS
We explore the behaviour of charged scalar solitons in asymptotically global
AdS4 spacetimes. This is motivated in part by attempting to identify under what
circumstances such objects can become large relative to the AdS length scale.
We demonstrate that such solitons generically do get large and in fact in the
planar limit smoothly connect up with the zero temperature limit of planar
scalar hair black holes. In particular, for given Lagrangian parameters we
encounter multiple branches of solitons: some which are perturbatively
connected to the AdS vacuum and surprisingly, some which are not. We explore
the phase space of solutions by tuning the charge of the scalar field and
changing scalar boundary conditions at AdS asymptopia, finding intriguing
critical behaviour as a function of these parameters. We demonstrate these
features not only for phenomenologically motivated gravitational Abelian-Higgs
models, but also for models that can be consistently embedded into eleven
dimensional supergravity.Comment: 62 pages, 21 figures. v2: added refs and comments and updated
appendice
Spectral plots and the representation and interpretation of biological data
It is basic question in biology and other fields to identify the char-
acteristic properties that on one hand are shared by structures from a
particular realm, like gene regulation, protein-protein interaction or neu- ral
networks or foodwebs, and that on the other hand distinguish them from other
structures. We introduce and apply a general method, based on the spectrum of
the normalized graph Laplacian, that yields repre- sentations, the spectral
plots, that allow us to find and visualize such properties systematically. We
present such visualizations for a wide range of biological networks and compare
them with those for networks derived from theoretical schemes. The differences
that we find are quite striking and suggest that the search for universal
properties of biological networks should be complemented by an understanding of
more specific features of biological organization principles at different
scales.Comment: 15 pages, 7 figure
The effect of high dose antibiotic impregnated cement on rate of surgical site infection after hip hemiarthroplasty for fractured neck of femur : a protocol for a double-blind quasi randomised controlled trial
Background:
Mortality following hip hemiarthroplasty is in the range of 10-40% in the first year, with much attributed to post-operative complications. One such complication is surgical site infection (SSI), which at the start of this trial affected 4.68% of patients in the UK having this operation. Compared to SSI rates of elective hip surgery, at less than 1%, this figure is elevated. The aim of this quasi randomised controlled trial (RCT) is to determine if high dose antibiotic impregnated cement can reduce the SSI in patients at 12-months after hemiarthroplasty for intracapsular fractured neck of femur.
Methods:
848 patients with an intracapsular fractured neck of femur requiring a hip hemiarthroplasty are been recruited into this two-centre double-blind quasi RCT. Participants were recruited before surgery and quasi randomised to standard care or intervention group. Participants, statistician and outcome assessors were blind to treatment allocation throughout the study. The intervention consisted of high dose antibiotic impregnated cement consisting of 1 gram Clindamycin and 1 gram of Gentamicin. The primary outcome is Health Protection Agency (HPA) defined deep surgical site infection at 12 months. Secondary outcomes include HPA defined superficial surgical site infection at 30 days, 30 and 90-day mortality, length of hospital stay, critical care stay, and complications.
Discussion:
Large randomised controlled trials assessing the effectiveness of a surgical intervention are uncommon, particularly in the speciality of orthopaedics. The results from this trial will inform evidence-based recommendations for antibiotic impregnated cement in the management of patients with a fractured neck of femur undergoing a hip hemiarthroplasty. If high dose antibiotic impregnated cement is found to be an effective intervention, implementation into clinical practice could improve long-term outcomes for patients undergoing hip hemiarthroplasty
First Results from Lattice Simulation of the PWMM
We present results of lattice simulations of the Plane Wave Matrix Model
(PWMM). The PWMM is a theory of supersymmetric quantum mechanics that has a
well-defined canonical ensemble. We simulate this theory by applying rational
hybrid Monte Carlo techniques to a naive lattice action. We examine the strong
coupling behaviour of the model focussing on the deconfinement transition.Comment: v3 20 pages, 8 figures, comment adde
Gauge-theoretic invariants for topological insulators: A bridge between Berry, Wess-Zumino, and Fu-Kane-Mele
We establish a connection between two recently-proposed approaches to the
understanding of the geometric origin of the Fu-Kane-Mele invariant
, arising in the context of 2-dimensional
time-reversal symmetric topological insulators. On the one hand, the
invariant can be formulated in terms of the Berry connection and
the Berry curvature of the Bloch bundle of occupied states over the Brillouin
torus. On the other, using techniques from the theory of bundle gerbes it is
possible to provide an expression for containing the square root
of the Wess-Zumino amplitude for a certain -valued field over the
Brillouin torus.
We link the two formulas by showing directly the equality between the above
mentioned Wess-Zumino amplitude and the Berry phase, as well as between their
square roots. An essential tool of independent interest is an equivariant
version of the adjoint Polyakov-Wiegmann formula for fields , of which we provide a proof employing only basic homotopy theory and
circumventing the language of bundle gerbes.Comment: 23 pages, 1 figure. To appear in Letters in Mathematical Physic
The design, evaluation, and reporting on non- pharmacological, cognition- oriented treatments for older adults: Results of a survey of experts
IntroductionCognitive decline and dementia significantly affect independence and quality of life in older adults; therefore, it is critical to identify effective cognition- oriented treatments (COTs; eg, cognitive training, rehabilitation) that can help maintain or enhance cognitive functioning in older adults, as well as reduce dementia risk or alleviate symptoms associated with pathological processes.MethodsThe Cognitive Intervention Design Evaluation and Reporting (CIDER), a working group from the Non- Pharmacological Interventions Professional Interest Area (NPI- PIA) of the Alzheimer’s Association conducted as survey in 2017 with experts in COTs worldwide. The survey’s aims were three- fold: (1) determine the common attitudes, beliefs, and practices of experts involved in the COTs research targeting older people; (2) identify areas of relative agreement and disagreement among experts in the field; and (3) offer a critical review of the literature, including recommendations for future research.ResultsThe survey identified several areas of agreements among experts on critical features of COTs, and on study design and outcome measures. Nevertheless, there were some areas with relative disagreement. Critically, expert opinions were not always supported by scientific evidence, suggesting that methodologic improvements are needed regarding design, implementation, and reporting of COTs. There was a clear consensus that COTs provide benefits and should be offered to cognitively unimpaired older adults, mild cognitive impairment (MCI), and mild dementia, but opinions differed for moderate and severe dementia. In addition, there is no consensus on the potential role of COTs in dementia prevention, indicating that future research should prioritize this aspect.DiscussionEvidence of COTs in older adults is encouraging, but additional evidence is needed to enhance dementia prevention. Consensus building and guidelines in the field are critical to improve and accelerate the development of high- quality evidence for COTs in cognitively unimpaired older adults, and those with MCI and dementia.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155935/1/trc212024_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155935/2/trc212024.pd
An Exact Fluctuating 1/2-BPS Configuration
This work explores the role of thermodynamic fluctuations in the two
parameter giant and superstar configurations characterized by an ensemble of
arbitrary liquid droplets or irregular shaped fuzzballs. Our analysis
illustrates that the chemical and state-space geometric descriptions exhibit an
intriguing set of exact pair correction functions and the global correlation
lengths. The first principle of statistical mechanics shows that the possible
canonical fluctuations may precisely be ascertained without any approximation.
Interestingly, our intrinsic geometric study exemplifies that there exist exact
fluctuating 1/2-BPS statistical configurations which involve an ensemble of
microstates describing the liquid droplets or fuzzballs. The Gaussian
fluctuations over an equilibrium chemical and state-space configurations
accomplish a well-defined, non-degenerate, curved and regular intrinsic
Riemannian manifolds for all physically admissible domains of black hole
parameters. An explicit computation demonstrates that the underlying chemical
correlations involve ordinary summations, whilst the state-space correlations
may simply be depicted by standard polygamma functions. Our construction
ascribes definite stability character to the canonical energy fluctuations and
to the counting entropy associated with an arbitrary choice of excited boxes
from an ensemble of ample boxes constituting a variety of Young tableaux.Comment: Minor changes, added references, 30 pages, 4 figures, PACS numbers:
04.70.-s: Physics of black holes; 04.70.-Bw: Classical black holes; 04.50.Gh
Higher-dimensional black holes, black strings, and related objects; 04.60.Cf
Gravitational aspects of string theory, accepted for publication in JHE
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