3,311 research outputs found
The Universe is not a Computer
When we want to predict the future, we compute it from what we know about the
present. Specifically, we take a mathematical representation of observed
reality, plug it into some dynamical equations, and then map the time-evolved
result back to real-world predictions. But while this computational process can
tell us what we want to know, we have taken this procedure too literally,
implicitly assuming that the universe must compute itself in the same manner.
Physical theories that do not follow this computational framework are deemed
illogical, right from the start. But this anthropocentric assumption has
steered our physical models into an impossible corner, primarily because of
quantum phenomena. Meanwhile, we have not been exploring other models in which
the universe is not so limited. In fact, some of these alternate models already
have a well-established importance, but are thought to be mathematical tricks
without physical significance. This essay argues that only by dropping our
assumption that the universe is a computer can we fully develop such models,
explain quantum phenomena, and understand the workings of our universe. (This
essay was awarded third prize in the 2012 FQXi essay contest; a new afterword
compares and contrasts this essay with Robert Spekkens' first prize entry.)Comment: 10 pages with new afterword; matches published versio
Inter-rater reliability of the Dysexecutive Questionnaire (DEX): comparative data from non-clinician respondents – all raters are not equal
Primary objective: The Dysexecutive Questionnaire (DEX) is used to obtain information about executive and emotional problems after neuropathology. The DEX is self-completed by the patient (DEX-S) and an independent rater such as a family member (DEX-I). This study examined the level of inter-rater agreement between either two or three non-clinician raters on the DEX-I in order to establish the reliability of DEX-I ratings.
Methods and procedures: Family members and/or carers of 60 people with mixed neuropathology completed the DEX-I. For each patient, DEX-I ratings were obtained from either two or three raters who knew the person well prior to brain injury.
Main outcomes and results: We obtained two independent-ratings for 60 patients and three independent-ratings for 36 patients. Intra-class correlations revealed that there was only a modest level of agreement for items, subscale and total DEX scores between raters for their particular family member. Several individual DEX items had low reliability and ratings for the emotion sub-scale had the lowest level of agreement.
Conclusions: Independent DEX ratings completed by two or more non-clinician raters show only moderate correlation. Suggestions are made for improving the reliability of DEX-I ratings.</p
Changes in behaviour drive inter-annual variability in the at-sea distribution of northern gannets
The at-sea distribution of seabirds primarily depends on the distance from their breeding colony, and the abundance, distribution and predictability of their prey, which are subject to strong spatial and temporal variation. Many seabirds have developed flexible foraging strategies to deal with this variation, such as increasing their foraging effort or switching to more predictable, less energy dense, prey, in poor conditions. These responses may vary both within and between individuals, and understanding this variability is vital to predict the population-level impacts of spatially explicit environmental disturbances, such as offshore windfarms. We conducted a multi-year tracking study in order to investigate the inter-annual variation in the foraging behaviour and location of a population of northern gannets breeding on Alderney in the English Channel. To do so, we investigated the link between individual-level behaviour and population-level behaviour. We found that a sample of gannets tracked in 2015 had longer trip durations, travelled further from the colony and had larger core foraging areas and home range areas than gannets tracked in previous years. This inter-annual variation may be associated with oceanographic conditions indexed by the North Atlantic Oscillation (NAO). Our findings suggest that this inter-annual variation was driven by individuals visiting larger areas in all of their trips rather than individuals diversifying to visit more, distinct areas. These findings suggest that, for gannets at least, if prey becomes less abundant or more widely distributed, more individuals may be required to forage further from the colony, thus increasing their likelihood of encountering pressures from spatially explicit anthropogenic disturbances
A guided self-help intervention supporting mental health professionals’ decisions regarding sharing of lived experience
Mental health professionals with lived experience often experience heightened stigma and fear that their competency may be questioned. We present a new intervention (HOP-MHP) designed to support them in decisions about sharing their lived experience and preliminary results regarding the intervention’s acceptability and feasibility
Can the skin make you fat? A role for the skin in regulating adipose tissue function and whole-body glucose and lipid homeostasis
This work was supported by the following funding: BBSRC-LIDO Studentship (PWC, MPP and EE); Diabetes UK project grant (15/0005154) (PWC); British Skin Foundation (RFH, MP); MedCity (RFH)
Homeostasis of metabolites in Escherichia coli on transition from anaerobic to aerobic conditions and the transient secretion of pyruvate
We have developed a method for rapid quenching of samples
taken from chemostat cultures of Escherichia coli that gives
reproducible and reliable measurements of extracellular and
intracellular metabolites by 1H NMR and have applied it
to study the major central metabolites during the transition
from anaerobic to aerobic growth. Almost all metabolites
showed a gradual change after perturbation with air, consistent
with immediate inhibition of pyruvate formate-lyase, dilution
of overflow metabolites and induction of aerobic enzymes.
Surprisingly, although pyruvate showed almost no change
in intracellular concentration, the extracellular concentration
transiently increased. The absence of intracellular accumulation
of pyruvate suggested that one or more glycolytic enzymes
might relocate to the cell membrane. To test this hypothesis,
chromosomal pyruvate kinase (pykF) was modified to express
either PykF-green fluorescent protein or PykF-FLAG fusion
proteins. Measurements showed that PykF-FLAG relocates to
the cell membrane within 5 min of aeration and then slowly
returns to the cytoplasm, suggesting that on aeration, PykF
associates with the membrane to facilitate secretion of pyruvate
to maintain constant intracellular levels
Occurrence of the Tamarix Leafhopper, Opsius stactogalus Fieber (Hemiptera: Cicadellidae), in Argentina
The paleartic tamarix leafhopper, Opsius stactogalus Fieber (Hemiptera: Cicadellidae), can reduce the growth of tamarisk due to the aggregate feeding imposed by their populations. The species was mentioned for Argentina in Metcalf's catalogue (1967) without locality or region reference, and the contributions on Cicadellidae published by many authors after Metcalf omitted this distributional data. Populations of O. stactogalus on Tamarix sp. were found in 12 sites between 28° 48′ to 39° 17′ S and 64° 06′ to 70° 04′ W, located in both the Neotropical and Andean biogeographic regions
VVV-WIT-08: the giant star that blinked
We report the serendipitous discovery of a late-type giant star that exhibited a smooth, eclipse-like drop in flux to a depth of 97 per cent. Minimum flux occurred in 2012 April and the total event duration was a few hundred days. Light curves in V, I, and Ks from the Optical Gravitational Lensing Experiment and VISTA Variables in the Via Lactea surveys show a remarkably achromatic event. During 17 yr of observational coverage of this source only one such event was detected. The physical properties of the giant star itself appear somewhat unusual, which may ultimately provide a clue towards the nature of the system. By modelling the event as an occultation by an object that is elliptical in projection with uniform transparency, we place limits on its physical size and velocity. We find that the occultation is unlikely to be due to a chance alignment with a foreground object. We consider a number of possible candidates for the occulter, which must be optically thick and possess a radius or thickness in excess of 0.25 au. None are completely satisfactory matches to all the data. The duration, depth, and relative achromaticity of the dip mark this out as an exceptionally unusual event, whose secret has still not been fully revealed. We find two further candidates in the VVV survey and we suggest that these systems, and two previously known examples, may point to a broad class of long-period eclipsing binaries wherein a giant star is occulted by a circumsecondary disc
Monitoring Cognitive and Emotional Processes Through Pupil and Cardiac Response During Dynamic Versus Logical Task
The paper deals with the links between physiological measurements and cognitive and emotional functioning. As long as the operator is a key agent in charge of complex systems, the definition of metrics able to predict his performance is a great challenge. The measurement of the physiological state is a very promising way but a very acute comprehension is required; in particular few studies compare autonomous nervous system reactivity according to specific cognitive processes during task performance and task related psychological stress is often ignored. We compared physiological parameters recorded on 24 healthy subjects facing two neuropsychological tasks: a dynamic task that require problem solving in a world that continually evolves over time and a logical task representative of cognitive processes performed by operators facing everyday problem solving. Results showed that the mean pupil diameter change was higher during the dynamic task; conversely, the heart rate was more elevated during the logical task. Finally, the systolic blood pressure seemed to be strongly sensitive to psychological stress. A better taking into account of the precise influence of a given cognitive activity and both workload and related task-induced psychological stress during task performance is a promising way to better monitor operators in complex working situations to detect mental overload or pejorative stress factor of error
Hardy's inequality for functions vanishing on a part of the boundary
We develop a geometric framework for Hardy's inequality on a bounded domain
when the functions do vanish only on a closed portion of the boundary.Comment: 26 pages, 2 figures, includes several improvements in Sections 6-8
allowing to relax the assumptions in the main results. Final version
published at http://link.springer.com/article/10.1007%2Fs11118-015-9463-
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