4,711 research outputs found

    Darwinism and Organizational Ecology: A Reply to Reydon and Scholz

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    In an earlier article published in this journal I challenge Reydon and Scholz's (2009) claim that Organizational Ecology is a non-Darwinian program. In this replay to Reydon and Scholz's subsequent response, I clarify the difference between our two approaches denoted by an emphasis her on the careful application of core Darwinian principles and an insistence by Reydon and Scholz on direct biological analogies. On a substantive issue, they identify as being the principle problem for Organizational Ecology, namely, the inability to identify replicators and interactors "of the right sort" in the business domain; this is also shown to be easily addressed with reference to empirical studies of business populations.Peer reviewedFinal Accepted Versio

    Two quantum Simpson's paradoxes

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    The so-called Simpson's "paradox", or Yule-Simpson (YS) effect, occurs in classical statistics when the correlations that are present among different sets of samples are reversed if the sets are combined together, thus ignoring one or more lurking variables. Here we illustrate the occurrence of two analogue effects in quantum measurements. The first, which we term quantum-classical YS effect, may occur with quantum limited measurements and with lurking variables coming from the mixing of states, whereas the second, here referred to as quantum-quantum YS effect, may take place when coherent superpositions of quantum states are allowed. By analyzing quantum measurements on low dimensional systems (qubits and qutrits), we show that the two effects may occur independently, and that the quantum-quantum YS effect is more likely to occur than the corresponding quantum-classical one. We also found that there exist classes of superposition states for which the quantum-classical YS effect cannot occur for any measurement and, at the same time, the quantum-quantum YS effect takes place in a consistent fraction of the possible measurement settings. The occurrence of the effect in the presence of partial coherence is discussed as well as its possible implications for quantum hypothesis testing.Comment: published versio

    Characterisation of different GLRaV-3 variant infections by determining virus concentration ratios and miRNA expression profiles

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    Grapevine leafroll disease (GLD) is present in all grape-growing regions of the world and is considered the most significant grapevine viral disease. Grapevine leafroll-associated virus 3 (GLRaV-3) is considered the primary cause of GLD and in South African vineyards five genetic variant groups (I, II, III, VI and VII) have been confirmed. Biological distinctions between GLRaV-3 variants have not been fully validated. By characterising virus concentration and stress-responsive microRNA expression in GLRaV-3 infected plants, this study aimed to glean a better understanding of the possible biological distinctions between GLRaV-3 variants. Quantitative reverse transcription PCR was utilised for virus concentration ratio (VCR) determination and miRNA quantitation in GLRaV-3 positive and negative grapevines grown under greenhouse and field conditions. This study found statistically significant differences in VCRs in plants singly infected with different GLRaV-3 variants. Interestingly, no difference in mean VCRs were observed between data sets, despite notable differences in plant age, duration of GLRaV-3 infection, scion/rootstock combination and growing conditions. Several miRNAs showed statistically significant expression modulation between infected and healthy samples. miRNA expression between data sets varied substantially and a greater overall miRNA response was observed in plants with more established GLRaV-3 infections. The lack of significant differences in mean VCRs between data sets, coupled with the consistent modulation of certain miRNAs in plants that have likely been infected for longer is a promising result. This finding could indicate that successful inhibition of further virus replication by plant defence mechanisms occurred, and that these miRNAs are implicated in this response

    What determines auditory similarity? The effect of stimulus group and methodology.

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    Two experiments on the internal representation of auditory stimuli compared the pairwise and grouping methodologies as means of deriving similarity judgements. A total of 45 undergraduate students participated in each experiment, judging the similarity of short auditory stimuli, using one of the methodologies. The experiments support and extend Bonebright's (1996) findings, using a further 60 stimuli. Results from both methodologies highlight the importance of category information and acoustic features, such as root mean square (RMS) power and pitch, in similarity judgements. Results showed that the grouping task is a viable alternative to the pairwise task with N > 20 sounds whilst highlighting subtle differences, such as cluster tightness, between the different task results. The grouping task is more likely to yield category information as underlying similarity judgements

    The effective mass of two--dimensional 3He

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    We use structural information from diffusion Monte Carlo calculations for two--dimensional 3He to calculate the effective mass. Static effective interactions are constructed from the density-- and spin structure functions using sumrules. We find that both spin-- and density-- fluctuations contribute about equally to the effective mass. Our results show, in agreement with recent experiments, a flattening of the single--particle self--energy with increasing density, which eventually leads to a divergent effective mass.Comment: 4 pages, accepted in PR

    Evaluation of Skylab (EREP) data for forest and rangeland surveys

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    The author has identified the following significant results. Four widely separated sites (near Augusta, Georgia; Lead, South Dakota; Manitou, Colorado; and Redding, California) were selected as typical sites for forest inventory, forest stress, rangeland inventory, and atmospheric and solar measurements, respectively. Results indicated that Skylab S190B color photography is good for classification of Level 1 forest and nonforest land (90 to 95 percent correct) and could be used as a data base for sampling by small and medium scale photography using regression techniques. The accuracy of Level 2 forest and nonforest classes, however, varied from fair to poor. Results of plant community classification tests indicate that both visual and microdensitometric techniques can separate deciduous, conifirous, and grassland classes to the region level in the Ecoclass hierarchical classification system. There was no consistency in classifying tree categories at the series level by visual photointerpretation. The relationship between ground measurements and large scale photo measurements of foliar cover had a correlation coefficient of greater than 0.75. Some of the relationships, however, were site dependent

    Forecasting neuromuscular recovery after anterior cruciate ligament injury: Athlete recovery profiles with generalized additive modeling

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    A retrospective analysis of longitudinally collected athlete monitoring data wasconducted to generate a model of neuromuscular recovery after anterior cruciateligament (ACL) injury and reconstruction (ACLR). Neuromuscular testing data in-cluding countermovement jump (CMJ) force‐time asymmetries and knee extensorstrength (maximum voluntary contractionext) asymmetries (between‐limb asymmetryindex—AI) were obtained from athletes with ACLR using semitendinosus (ST) au-tograft (n= 29; AI measurements: n= 494), bone patellar tendon bone autograft(n= 5; AI measurements:n= 88) and noninjured controls (n= 178; AI measurements:n= 3188). Explosive strength measured as the rate of torque development was alsocalculated. CMJ force‐time asymmetries were measured over discrete movementphases (eccentric deceleration phase, concentric phase). Separate additive mixedeffects models (additive mixed effects model [AMM]) were fit for each AI with amain effect for the surgical technique and a smooth term for the time since surgery(days). The models explained between 43% and 91% of the deviance in neuro-muscular recovery after ACLR. The mean time course was generated from the AMM.Comparative neuromuscular recovery profiles of an athlete with an acceleratedprogression and an athlete with a delayed progression after a serious multiligamentinjury were generated. Clinical Significance: This paper provides a new perspectiveon the utility of longitudinal athlete monitoring including routine testing to developmodels of neuromuscular recovery after ACLR that can be used to characterizeindividual progression throughout rehabilitation

    Intelligence within BAOR and NATO's Northern Army Group

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    During the Cold War the UK's principal military role was its commitment to the North Atlantic Treaty Organisation (NATO) through the British Army of the Rhine (BAOR), together with wartime command of NATO's Northern Army Group. The possibility of a surprise attack by the numerically superior Warsaw Pact forces ensured that great importance was attached to intelligence, warning and rapid mobilisation. As yet we know very little about the intelligence dimension of BAOR and its interface with NATO allies. This article attempts to address these neglected issues, ending with the impact of the 1973 Yom Kippur War upon NATO thinking about warning and surprise in the mid-1970s. It concludes that the arrangements made by Whitehall for support to BAOR from national assets during crisis or transition to war were - at best - improbable. Accordingly, over the years, BAOR developed its own unique assets in the realm of both intelligence collection and special operations in order to prepare for the possible outbreak of conflict
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