8,424 research outputs found

    Predators reduce extinction risk in noisy metapopulations

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    Background Spatial structure across fragmented landscapes can enhance regional population persistence by promoting local “rescue effects.” In small, vulnerable populations, where chance or random events between individuals may have disproportionately large effects on species interactions, such local processes are particularly important. However, existing theory often only describes the dynamics of metapopulations at regional scales, neglecting the role of multispecies population dynamics within habitat patches. Findings By coupling analysis across spatial scales we quantified the interaction between local scale population regulation, regional dispersal and noise processes in the dynamics of experimental host-parasitoid metapopulations. We find that increasing community complexity increases negative correlation between local population dynamics. A potential mechanism underpinning this finding was explored using a simple population dynamic model. Conclusions Our results suggest a paradox: parasitism, whilst clearly damaging to hosts at the individual level, reduces extinction risk at the population level

    Can Civic and Moral Education Be Distinguished?

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    Para pengajar pendidikan kewarganegaraan selalu mengalami dilemma antara pengajaran nilai-nilai kewarganegaraan dengan pendidikan moral. Jika terfokus kepada yang pertama, pengajaran hanya akan berupa observasi antropologis terhadap fakta-fakta empiris pada suatu bangsa. Sementara jika menekankan kepada pendidikan moral per se, meskipun normatif tetapi sarat dengan premis-premis metafisik yang kontroversial yang mungkin tidak semua siswa dapat menerimanya. Untuk memecahkannya banyak teori politik dan pendidikan telah dirumuskan diantaranya civic religion dari Gutmann, teori komunitarian Rober N. Bellah dan mungkin yang paling relevan adalah paham libertarian yang bicara soal keadilan dari John Rawls dan lain-lain. Semuanya akan diintegrasikan dalam kurikulum yang bertujuan untuk memberi kemampuan siswa untuk memahami konsensus, bagaimama memahami masyarakat dan memahami hubungan antara merefleksikan hubyungan tersebut serta membangun moral pribadi mereka. Rawls percaya bahwa pendidikan harus mengajak kepada keterlibatan dalam dialog publik mengenai nilai-nilai kewarganegaraan demi merumuskan sebuah moralitas pribadi

    Cross correlation surveys with the Square Kilometre Array

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    By the time that the first phase of the Square Kilometre Array is deployed it will be able to perform state of the art Large Scale Structure (LSS) as well as Weak Gravitational Lensing (WGL) measurements of the distribution of matter in the Universe. In this chapter we concentrate on the synergies that result from cross-correlating these different SKA data products as well as external correlation with the weak lensing measurements available from CMB missions. We show that the Dark Energy figures of merit obtained individually from WGL/LSS measurements and their independent combination is significantly increased when their full cross-correlations are taken into account. This is due to the increased knowledge of galaxy bias as a function of redshift as well as the extra information from the different cosmological dependences of the cross-correlations. We show that the cross-correlation between a spectroscopic LSS sample and a weak lensing sample with photometric redshifts can calibrate these same photometric redshifts, and their scatter, to high accuracy by modelling them as nuisance parameters and fitting them simultaneously cosmology. Finally we show that Modified Gravity parameters are greatly constrained by this cross-correlations because weak lensing and redshift space distortions (from the LSS survey) break strong degeneracies in common parameterisations of modified gravity.Comment: 12 pages, 3 figures. This article is part of the 'Cosmology Chapter, Advancing Astrophysics with the SKA (AASKA14) Conference, Giardini Naxos (Italy), June 9th-13th 2014

    A Note on the Efficiencies of Sampling Strategies in Two-Stage Bayesian Regional Fine Mapping of a Quantitative Trait

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    ABSTRACT: In focused studies designed to follow up associations detected in a genome-wide association study (GWAS), investigators can proceed to fine-map a genomic region by targeted sequencing or dense genotyping of all variants in the region, aiming to identify a functional sequence variant. For the analysis of a quantitative trait, we consider a Bayesian approach to fine-mapping study design that incorporates stratification according to a promising GWAS tag SNP in the same region. Improved cost-efficiency can be achieved when the fine-mapping phase incorporates a two-stage design, with identification of a smaller set of more promising variants in a subsample taken in stage 1, followed by their evaluation in an independent stage 2 subsample. To avoid the potential negative impact of genetic model misspecification on inference we incorporate genetic model selection based on posterior probabilities for each competing model. Our simulation study shows that, compared to simple random sampling that ignores genetic information from GWAS, tag-SNP-based stratified sample allocation methods reduce the number of variants continuing to stage 2 and are more likely to promote the functional sequence variant into confirmation studies

    An Autonomous Flight Safety System

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    The Autonomous Flight Safety System (AFSS) being developed by NASA s Goddard Space Flight Center s Wallops Flight Facility and Kennedy Space Center has completed two successful developmental flights and is preparing for a third. AFSS has been demonstrated to be a viable architecture for implementation of a completely vehicle based system capable of protecting life and property in event of an errant vehicle by terminating the flight or initiating other actions. It is capable of replacing current human-in-the-loop systems or acting in parallel with them. AFSS is configured prior to flight in accordance with a specific rule set agreed upon by the range safety authority and the user to protect the public and assure mission success. This paper discusses the motivation for the project, describes the method of development, and presents an overview of the evolving architecture and the current status

    Enhancing the cognitive interview with an alternative procedure to witness-compatible questioning: category clustering recall

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    The Cognitive Interview (CI) is one of the most widely studied and used methods to interview witnesses. However, new component techniques for further increasing correct recall are still crucial. We focused on how a new and simpler interview strategy, Category Clustering Recall (CCR), could increase recall in comparison with witness-compatible questioning and tested if a Revised Cognitive Interview (RCI) with CCR instead of witness-compatible questioning and without the change order and change perspective mnemonics would be effective for this purpose. Participants watched a mock robbery video and were interviewed 48 hours later with either the CI or the RCI. Recalled information was classified as either correct, incorrect or confabulation. Although exclusion of the change order and change perspective mnemonics in the RCI group might have caused a slight decrease in recall during the last interview phases, the RCI group generally produced more correct information than the CI group, with a lower number of confabulations. Further analyses revealed CCR was largely responsible for this increase in correct recall. CCR is a very promising interview technique which allowed the interviewer to obtain more detailed information without additional questions and may have, in certain situations, several practical advantages over a questioning phase.N/

    Foreground Subtraction in Intensity Mapping with the SKA

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    21cm intensity mapping experiments aim to observe the diffuse neutral hydrogen (HI) distribution on large scales which traces the Cosmic structure. The Square Kilometre Array (SKA) will have the capacity to measure the 21cm signal over a large fraction of the sky. However, the redshifted 21cm signal in the respective frequencies is faint compared to the Galactic foregrounds produced by synchrotron and free-free electron emission. In this article, we review selected foreground subtraction methods suggested to effectively separate the 21cm signal from the foregrounds with intensity mapping simulations or data. We simulate an intensity mapping experiment feasible with SKA phase 1 including extragalactic and Galactic foregrounds. We give an example of the residuals of the foreground subtraction with a independent component analysis and show that the angular power spectrum is recovered within the statistical errors on most scales. Additionally, the scale of the Baryon Acoustic Oscillations is shown to be unaffected by foreground subtraction.Comment: This article is part of the 'SKA Cosmology Chapter, Advancing Astrophysics with the SKA (AASKA14), Conference, Giardini Naxos (Italy), June 9th-13th 2014
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