88 research outputs found
Interpolating the Sherrington-Kirkpatrick replica trick
The interpolation techniques have become, in the past decades, a powerful
approach to lighten several properties of spin glasses within a simple
mathematical framework. Intrinsically, for their construction, these schemes
were naturally implemented into the cavity field technique, or its variants as
the stochastic stability or the random overlap structures. However the first
and most famous approach to mean field statistical mechanics with quenched
disorder is the replica trick. Among the models where these methods have been
used (namely, dealing with frustration and complexity), probably the best known
is the Sherrington-Kirkpatrick spin glass: In this paper we are pleased to
apply the interpolation scheme to the replica trick framework and test it
directly to the cited paradigmatic model: interestingly this allows to obtain
easily the replica-symmetric control and, synergically with the broken replica
bounds, a description of the full RSB scenario, both coupled with several minor
theorems. Furthermore, by treating the amount of replicas as an
interpolating parameter (far from its original interpretation) this can be
though of as a quenching temperature close to the one introduce in
off-equilibrium approaches and, within this viewpoint, the proof of the
attended commutativity of the zero replica and the infinite volume limits can
be obtained.Comment: This article is dedicated to David Sherrington on the occasion of his
seventieth birthda
Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae)
Background: Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization. Results: We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family. Conclusions: Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.Peer reviewe
Definitions, Foundations and Associations of Physical Literacy: A Systematic Review
Background: The concept of physical literacy has stimulated increased research attention in recent years—being deployed in physical education, sport participation, and the promotion of physical activity. Independent research groups currently operationalize the construct differently. Objective The purpose of this systematic review was to conduct a systematic review of the physical literacy construct,as reflected in contemporary research literature. Methods: Five databases were searched using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for systematic reviews. Inclusion criteria were English language, peer reviewed, published by March 2016, and seeking to conceptualize physical literacy. Articles that met these criteria were analysed in relation to three core areas: properties/attributes, philosophicalfoundations and theoretical associations with other constructs. A total of 50 published articles met the inclusion criteria and were analysed qualitatively using inductive thematic analysis.Results: The thematic analysis addressed the three core areas. Under definitions, core attributes that define physical literacy were identified, as well as areas of conflict between different approaches currently being adopted. One relatively clear philosophical approach was prominent in approximately half of the papers, based on a monist/holistic ontology and phenomenological epistemology. Finally, theanalysis identified a number of theoretical associations, including health, physical activity and academic performance.Conclusions: Current literature contains different representations of the physical literacy construct. The costs and benefits of adopting an exclusive approach versus pluralism are considered. Recommendations for both researchers and practitioners focus on identifying and clearly articulating the definitions, philosophical assumptions and expected outcomes prior to evaluating the effectiveness of this emerging concept
The influence of input and output modality on following instructions in working memory
Following instructions is an important component of learning and has been shown to rely on working memory. This study examined the ability to follow instructions within working memory under varying input and output modalities. In Experiment 1, participants heard, read, or viewed demonstration of short sequences of instructions, and recalled either by oral repetition or physical enactment. There was a significant main effect of encoding, showing superior recall performance when instructions were demonstrated relative to spoken or written presentation. Experiment 2 examined whether recall is further improved when instructions are presented both in spoken and demonstrated form, relative to single modality presentation. The advantage for demonstration over spoken instructions was replicated, and dual input was superior to spoken instructions. However, dual input did not bring extra benefit compared to demonstration of instructions. We also observed a significant enacted-retrieval recall advantage. These findings suggest effects of both input and output modalities on the ability to remember and follow instructions in working memory. Outcomes substantially inform the underexplored but important new area of action-based working memory and its links to embodied cognition, with implications for pedagogic practice
Similarities between the irrelevant sound effect and the suffix effect
Although articulatory suppression abolishes the effect of irrelevant sound (ISE) on serial recall when sequences are presented visually, the effect persists with auditory presentation of list items. Two experiments were designed to test the claim that, when articulation is suppressed, the effect of irrelevant sound on the retention of auditory lists resembles a suffix effect. A suffix is a spoken word that immediately follows the final item in a list. Even though participants are told to ignore it, the suffix impairs serial recall of auditory lists. In Experiment 1, the irrelevant sound consisted of instrumental music. The music generated a significant ISE that was abolished by articulatory suppression. It therefore appears that, when articulation is suppressed, irrelevant sound must contain speech for it to have any effect on recall. This is consistent with what is known about the suffix effect. In Experiment 2, the effect of irrelevant sound under articulatory suppression was greater when the irrelevant sound was spoken by the same voice that presented the list items. This outcome is again consistent with the known characteristics of the suffix effect. It therefore appears that, when rehearsal is suppressed, irrelevant sound disrupts the acoustic-perceptual encoding of auditorily presented list items. There is no evidence that the persistence of the ISE under suppression is a result of interference to the representation of list items in a postcategorical phonological store
Man and the Last Great Wilderness: Human Impact on the Deep Sea
The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life – SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO2 and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO2 and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods
‘Measuring’ Physical Literacy and Related Constructs: A Systematic Review of Empirical Findings
BACKGROUND:The concept of physical literacy has received increased research and international attention recently. Where intervention programs and empirical research are gaining momentum, their operationalizations differ significantly.OBJECTIVE:The objective of this study was to inform practice in the measure/assessment of physical literacy via a systematic review of research that has assessed physical literacy (up to 14 June, 2017).METHODS:Five databases were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols guidelines, with 32 published articles meeting the inclusion criteria. English-language, peer-reviewed published papers containing empirical studies of physical literacy were analyzed using inductive thematic analysis.RESULTS:Qualitative methods included: (1) interviews; (2) open-ended questionnaires; (3) reflective diaries; (4) focus groups; (5) participant observations; and (6) visual methods. Quantitative methods included: (1) monitoring devices (e.g., accelerometers); (2) observations (e.g., of physical activity or motor proficiency); (3) psychometrics (e.g., enjoyment, self-perceptions); (4) performance measures (e.g., exergaming, objective times/distances); (5) anthropometric measurements; and (6) one compound measure. Of the measures that made an explicit distinction: 22 (61%) examined the physical domain, eight (22%) the affective domain; five (14%) the cognitive domain; and one (3%) combined three domains (physical, affective, and cognitive) of physical literacy. Researchers tended to declare their philosophical standpoint significantly more in qualitative research compared with quantitative research.CONCLUSIONS:Current research adopts diverse often incompatible methodologies in measuring/assessing physical literacy. Our analysis revealed that by adopting simplistic and linear methods, physical literacy cannot be measured/assessed in a traditional/conventional sense. Therefore, we recommend that researchers are more creative in developing integrated philosophically aligned approaches to measuring/assessing physical literacy. Future research should consider the most recent developments in the field of physical literacy for policy formation
Working Memory Underpins Cognitive Development, Learning, and Education
Working memory is the retention of a small amount of information in a readily accessible form. It facilitates planning, comprehension, reasoning, and problem-solving. I examine the historical roots and conceptual development of the concept and the theoretical and practical implications of current debates about working memory mechanisms. Then I explore the nature of cognitive developmental improvements in working memory, the role of working memory in learning, and some potential implications of working memory and its development for the education of children and adults. The use of working memory is quite ubiquitous in human thought, but the best way to improve education using what we know about working memory is still controversial. I hope to provide some directions for research and educational practice
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