731 research outputs found
Cooperative Adaptive Control for Cloud-Based Robotics
This paper studies collaboration through the cloud in the context of
cooperative adaptive control for robot manipulators. We first consider the case
of multiple robots manipulating a common object through synchronous centralized
update laws to identify unknown inertial parameters. Through this development,
we introduce a notion of Collective Sufficient Richness, wherein parameter
convergence can be enabled through teamwork in the group. The introduction of
this property and the analysis of stable adaptive controllers that benefit from
it constitute the main new contributions of this work. Building on this
original example, we then consider decentralized update laws, time-varying
network topologies, and the influence of communication delays on this process.
Perhaps surprisingly, these nonidealized networked conditions inherit the same
benefits of convergence being determined through collective effects for the
group. Simple simulations of a planar manipulator identifying an unknown load
are provided to illustrate the central idea and benefits of Collective
Sufficient Richness.Comment: ICRA 201
A review of the microbiome associated with human decomposition
The decomposition of human remains involves a complex microbial ecology that few studies have examined in depth. This review investigated the microbiome of human decomposition to further understand their functions within the decomposition process and their potential to increase the accuracy of post-mortem interval (PMI) estimations in forensic applications. The aims of the literature review were to (1) identify the external microbiome responsible for human decomposition, focusing on insect, soil and skin sources, (2) determine the roles of external bacteria in the various stages of human decomposition and (3) to analyse and compare the current contributions of literature in furthering the understanding of the ecological mosaic of decomposition.
The current literature was reviewed and their contributions to necrobiome research was analysed using qualitative and contemporary research techniques. Bacteria were found to play a significant role in each stage of human decomposition with multiple studies demonstrating an observable successive shift in microbial communities through time. This change in community profile was found to be an important biomarker for the estimation of the PMI and potential substitute for entomological techniques currently utilised in forensic investigations. High interpersonal variation between decomposition events, in addition to narrow geographic specificity, represented limitations in the studies which may be remedied by increasing sample size while focusing on different geographic regions and environmental conditions
Vertebrate Damage Management: The Future of an Evolving Profession
The author argues that an objective of a new group of people taking a systems approach to large wild animal problems should be to manage damage as a cost-reducing role within a total, profitable, long-term system, not necessarily to control the pest. The needs are for well-grounded financial analyses both for customers, the public, the resources, and the well-being of the profession. A point of view is advanced for the need for evolving pest-related operations into a new, unique profession that is involved in a profound way as an element of a cost-effective total land and human resource production system
IST Austria Thesis
Bacteria and their pathogens – phages – are the most abundant living entities on Earth. Throughout their coevolution, bacteria have evolved multiple immune systems to overcome the ubiquitous threat from the phages. Although the molecu- lar details of these immune systems’ functions are relatively well understood, their epidemiological consequences for the phage-bacterial communities have been largely neglected. In this thesis we employed both experimental and theoretical methods to explore whether herd and social immunity may arise in bacterial popu- lations. Using our experimental system consisting of Escherichia coli strains with a CRISPR based immunity to the T7 phage we show that herd immunity arises in phage-bacterial communities and that it is accentuated when the populations are spatially structured. By fitting a mathematical model, we inferred expressions for the herd immunity threshold and the velocity of spread of a phage epidemic in partially resistant bacterial populations, which both depend on the bacterial growth rate, phage burst size and phage latent period. We also investigated the poten- tial for social immunity in Streptococcus thermophilus and its phage 2972 using a bioinformatic analysis of potentially coding short open reading frames with a signalling signature, encoded within the CRISPR associated genes. Subsequently, we tested one identified potentially signalling peptide and found that its addition to a phage-challenged culture increases probability of survival of bacteria two fold, although the results were only marginally significant. Together, these results demonstrate that the ubiquitous arms races between bacteria and phages have further consequences at the level of the population
On the detectability of latitudinal biodiversity gradients in deep time
The latitudinal biodiversity gradient (LBG), in which species richness increases from the poles to tropical regions, is one of the most pervasive biodiversity patterns today. However, deep-time studies suggest that the LBG has varied in the geological past, with a range of taxonomic groups characterised by flattened or even bimodal gradients. Moreover, these studies suggest that tropical peaks and poleward declines in biodiversity are restricted to intervals of the Palaeozoic, and the last 30 million years (Myr), when cool icehouse climatic regimes persisted. Yet, the reconstruction of macroecological patterns in deep time is hampered by inherent geological and anthropogenic biases. In particular, spatial sampling heterogeneity has the potential to hinder the reconstruction of LBGs due to the ubiquitous scaling of species richness with area. In this thesis, a series of case studies that attempt to quantify the impact of spatial sampling heterogeneity on the reconstruction of LBGs are presented. Earth System and ecological niche modelling are applied to test whether observed biodiversity trends are the result of spatial sampling heterogeneity, or a genuine biological signal. In addition, a novel subsampling protocol is implemented to provide sampling-standardised estimates of biodiversity. Collectively, this work suggests spatial sampling heterogeneity often prevents the recovery of genuine LBGs in deep time. Estimates of zooxanthellate coral richness over the past 250 Myr demonstrate that the modern LBG got markedly steeper during the last 20 Myr, and a unimodal-type LBG likely persisted during the Early Cretaceous, coinciding with a geologically long-lived ‘cold-snap’. These findings are supported by ecological niche modelling, which suggest a tropical increase, and temperate decline in suitable habitat area during these intervals. Overall, these studies highlight the significance of correcting for spatial sampling heterogeneity when reconstructing biodiversity patterns from the fossil record, as well as the value of inferential methods in understanding past macroecological patterns.Open Acces
Benchmarking Eventually Consistent Distributed Storage Systems
Cloud storage services and NoSQL systems typically offer only "Eventual Consistency", a rather weak guarantee covering a broad range of potential data consistency behavior. The degree of actual (in-)consistency, however, is unknown. This work presents novel solutions for determining the degree of (in-)consistency via simulation and benchmarking, as well as the necessary means to resolve inconsistencies leveraging this information
Internal EAPs and the low-wage Worker: Practitioners'Perceptions of Services
INTERNAL EMPLOYEE ASSISTANCE PROGRAMS AND LOW-WAGE WORKERS: PRACTITIONERS' PERCEPTIONS OF SERVICES Kathleen E. McDonough, PhD University of Pittsburgh, 2005 Utilizing a mailing list secured from the Employee Assistance Professionals' Association, practitioners of internal employee assistance programs (EAPs) were surveyed to assess their perceptions of how their programs compared in service provision between low-wage and other workers. The sample consisted of 71 respondents, and was gender-balanced but overwhelmingly Caucasian. Respondents estimated minor differences between the two worker groups in program utilization, but programs that offered concrete, tangible services had higher low-wage utilization rates. Supervisory and human resource referrals were generally higher for low-wage workers, but programs that used a variety of promotional strategies had higher low-wage self-refer rates. There were no major disparities in problem categories between the two groups with the exception of financial and attendance difficulties. Respondents rated their EAPs helpfulness with low-wage workers positively, but were less optimistic in comparison to other workers. The majority of respondents did not perceive major differences in treatment between the two worker groups, but they did think that low-wage workers were less likely to remain in treatment. Analyses of responses to open-ended items sometimes conflicted with the quantitative data. Implications for practice and policy in EAP service provision to low-wage workers and recommendations for future research are discussed. ii
Analysis of 1321 Eubacterium rectale genomes from metagenomes uncovers complex phylogeographic population structure and subspecies functional adaptations
Funding This work was supported by NIH NHGRI grant R01HG005220, NIDDK grant R24DK110499, NIDDK grant U54DE023798, and CMIT grant 6935956 to C.H., and by the European Research Council (ERC-STG project MetaPG-716575), MIUR “Futuro in Ricerca” RBFR13EWWI_001, the European Union (H2020-SFS-2018-1 project MASTER-818368 and H2020-SC1-BHC project ONCOBIOME-825410), and the National Cancer Institute of the National Institutes of Health (1U01CA230551) to N.S. Further support was provided by the Programma Ricerca Budget prestazioni Eurac 2017 of the Province of Bolzano, Italy to F.M., and by the EU-H2020 (DiMeTrack-707345) to E.P. and N.S. D.B., S.H.D., P.L., A.W.W. and The Rowett Institute received core funding support from the Scottish Government Rural and Environmental Sciences and Analytical Services (SG-RESAS). Availability of data and materials All datasets used in this study are publicly available and matched with their respective PMID (Additional file 5). The high-quality E. rectale MAGs in fasta format and a metadata file are available at http://segatalab.cibio.unitn.it/data/Erectale_Karcher_et_al.html and in the following Zenodo repository: https://doi.org/10.5281/zenodo.3763191 [80]. The two new isolate genomes L2–21 and T3BWe13 have been uploaded to NCBI and can be found in RefSeq under the accession numbers GCF_008122485.1 [81] and GCF_008123415.1 [82], respectively.Peer reviewedPublisher PD
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