235 research outputs found
Stranger than Fiction: A Qualitative Thesis Examining Leaders, Followers and the Distribution of Power in the 2016 United States Presidential Election
Historically, the leadership literature mentions the role of followers only in passing. New research is emerging about the importance of followers and the role they play in the distribution of power between leaders and followers. Using Kellerman\u27s theory of leadership as a theoretical framework, this study positions engaged voters as followers in the 2016 Presidential election, and examines their perceptions of the election and its relationship to the distribution of power between leaders and followers. The findings reveal that in a context marked by dissatisfaction, political polarization and technology, followers in this study want change, but cannot or do not envision it beyond the bounds of the current governmental system
Tissue-specific network-based genome wide study of amygdala imaging phenotypes to identify functional interaction modules
Motivation:
Network-based genome-wide association studies (GWAS) aim to identify functional modules from biological networks that are enriched by top GWAS findings. Although gene functions are relevant to tissue context, most existing methods analyze tissue-free networks without reflecting phenotypic specificity.
Results:
We propose a novel module identification framework for imaging genetic studies using the tissue-specific functional interaction network. Our method includes three steps: (i) re-prioritize imaging GWAS findings by applying machine learning methods to incorporate network topological information and enhance the connectivity among top genes; (ii) detect densely connected modules based on interactions among top re-prioritized genes; and (iii) identify phenotype-relevant modules enriched by top GWAS findings. We demonstrate our method on the GWAS of [18F]FDG-PET measures in the amygdala region using the imaging genetic data from the Alzheimer's Disease Neuroimaging Initiative, and map the GWAS results onto the amygdala-specific functional interaction network. The proposed network-based GWAS method can effectively detect densely connected modules enriched by top GWAS findings. Tissue-specific functional network can provide precise context to help explore the collective effects of genes with biologically meaningful interactions specific to the studied phenotype
The proteome of extracellular vesicles released by clastic cells differs based on their substrate
Extracellular vesicles (EVs) from osteoclasts are important regulators in intercellular communication. Here, we investigated the proteome of EVs from clastic cells plated on plastic
(clasts), bone (osteoclasts) and dentin (odontoclasts) by two-dimensional high performance
liquid chromatography mass spectrometry seeking differences attributable to distinct mineralized matrices. A total of 1,952 proteins were identified. Of the 500 most abundant proteins
in EVs, osteoclast and odontoclast EVs were 83.3% identical, while clasts shared 70.7% of
the proteins with osteoclasts and 74.2% of proteins with odontoclasts. For each protein, the
differences between the total ion count values were mapped to an expression ratio histogram (Z-score) in order to detect proteins differentially expressed. Stabilin-1 and macrophage mannose receptor-1 were significantly-enriched in EVs from odontoclasts compared
with osteoclasts (Z = 2.45, Z = 3.34) and clasts (Z = 13.86, Z = 1.81) and were abundant in
odontoclast EVs. Numerous less abundant proteins were differentially-enriched. Subunits of
known protein complexes were abundant in clastic EVs, and were present at levels consistent with them being in assembled protein complexes. These included the proteasome,
COP1, COP9, the T complex and a novel sub-complex of vacuolar H+
-ATPase (V-ATPase),
which included the (pro) renin receptor. The (pro) renin receptor was immunoprecipitated
using an anti-E-subunit antibody from detergent-solubilized EVs, supporting the idea that
the V-ATPase subunits present were in the same protein complex. We conclude that the
protein composition of EVs released by clastic cells changes based on the substrate. Clastic
EVs are enriched in various protein complexes including a previously undescribed VATPase sub-complex
Beluga Vocalizations Decrease in Response to Vessel Traffic in the Mackenzie River Estuary
Vessel traffic negatively affects marine mammals by causing behavioural disturbance, acoustic masking, contamination (i.e., oil spills), and ship strikes. Few studies have examined the effects of vessels on marine mammals in the Arctic, but beluga whales appear to be especially sensitive to vessel traffic. We examine how the vocalizations of belugas are impacted by vessel traffic in the Tarium Niryutait Marine Protected Area in the Mackenzie River estuary of the western Canadian Arctic. Between one and four acoustic recorders were deployed between June and August each year between 2015 and 2018 near the only shipping channel at this site. We examined beluga vocalizations from acoustic recordings over four summers and assessed how the distance to the nearest vessel passing the acoustic recorder affected the number of vocalizations. Beluga vocalizations within the range of the acoustic recorder decreased significantly when vessels were within 5 km of the acoustic recorder. This result suggests either that belugas are avoiding the vessel or that they reduce their vocalization in response to vessel traffic. Future work is needed to assess exactly how belugas are reacting to vessel traffic in this area and what the long-term consequences of these reactions are. Management measures for reducing these impacts must be carefully considered, especially since these vessels are very restricted in where they can travel, and many of the vessels are necessary for the livelihoods of local communities.La circulation maritime a des effets négatifs sur les mammifères marins, car elle entraîne des perturbations comportementales, masque leurs signaux acoustiques et engendre de la contamination (comme des déversements de pétrole) et des collisions. Bien que peu d’études aient examiné les effets des bateaux sur les mammifères marins de l’Arctique, les bélugas semblent particulièrement sensibles à la circulation maritime. Dans cet article, nous examinons en quoi les vocalisations des bélugas sont touchées par la circulation maritime dans la zone de protection marine de Tarium Niryutait faisant partie de l’estuaire du fleuve Mackenzie, dans l’ouest de l’Arctique canadien. Entre un et quatre enregistreurs acoustiques ont été déployés de juin à août de chaque année entre 2015 et 2018, à proximité du seul chenal de navigation de l’endroit. Nous avons examiné les vocalisations des bélugas prélevées à l’aide des enregistreurs acoustiques au cours de quatre étés, et évalué en quoi la distance du bateau passant le plus près de l’enregistreur acoustique avait un effet sur le nombre de vocalisations. Les vocalisations des bélugas dans la zone de l’enregistreur acoustique diminuaient considérablement lorsque les bateaux se trouvaient à moins de cinq kilomètres de l’enregistreur. Ce résultat suggère soit que les bélugas évitent les bateaux, soit qu’ils réduisent leurs vocalisations en réponse à la circulation maritime. Il y a lieu de pousser cette étude plus loin pour évaluer exactement comment les bélugas réagissent à la circulation des bateaux dans cette région, et quelles sont les conséquences à long terme de ces réactions. Il y a lieu aussi de considérer avec soin des mesures de gestion pour réduire ces incidences, surtout parce que les déplacements de ces bateaux sont assujettis à de nombreuses restrictions et parce que grand nombre des bateaux qui passent par là sont nécessaires à la subsistance des collectivités de la région.
 
Computability with polynomial differential equations
In this paper, we show that there are Initial Value Problems de ned
with polynomial ordinary di erential equations that can simulate univer-
sal Turing machines in the presence of bounded noise. The polynomial
ODE de ning the IVP is explicitly obtained and the simulation is per-
formed in real time
A Survey on Continuous Time Computations
We provide an overview of theories of continuous time computation. These
theories allow us to understand both the hardness of questions related to
continuous time dynamical systems and the computational power of continuous
time analog models. We survey the existing models, summarizing results, and
point to relevant references in the literature
Release of Severe Acute Respiratory Syndrome Coronavirus Nuclear Import Block Enhances Host Transcription in Human Lung Cells
The severe acute respiratory syndrome coronavirus accessory protein ORF6 antagonizes interferon signaling by blocking karyopherin-mediated nuclear import processes. Viral nuclear import antagonists, expressed by several highly pathogenic RNA viruses, likely mediate pleiotropic effects on host gene expression, presumably interfering with transcription factors, cytokines, hormones, and/or signaling cascades that occur in response to infection. By bioinformatic and systems biology approaches, we evaluated the impact of nuclear import antagonism on host expression networks by using human lung epithelial cells infected with either wild-type virus or a mutant that does not express ORF6 protein. Microarray analysis revealed significant changes in differential gene expression, with approximately twice as many upregulated genes in the mutant virus samples by 48 h postinfection, despite identical viral titers. Our data demonstrated that ORF6 protein expression attenuates the activity of numerous karyopherin-dependent host transcription factors (VDR, CREB1, SMAD4, p53, EpasI, and Oct3/4) that are critical for establishing antiviral responses and regulating key host responses during virus infection. Results were confirmed by proteomic and chromatin immunoprecipitation assay analyses and in parallel microarray studies using infected primary human airway epithelial cell cultures. The data strongly support the hypothesis that viral antagonists of nuclear import actively manipulate host responses in specific hierarchical patterns, contributing to the viral pathogenic potential in vivo. Importantly, these studies and modeling approaches not only provide templates for evaluating virus antagonism of nuclear import processes but also can reveal candidate cellular genes and pathways that may significantly influence disease outcomes following severe acute respiratory syndrome coronavirus infection in vivo
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