605 research outputs found

    Hierarchical core-periphery structure in networks

    Full text link
    We study core-periphery structure in networks using inference methods based on a flexible network model that allows for traditional onion-like cores within cores, but also for hierarchical tree-like structures and more general non-nested types of structure. We propose an efficient Monte Carlo scheme for fitting the model to observed networks and report results for a selection of real-world data sets. Among other things, we observe an empirical distinction between networks showing traditional core-periphery structure with a dense core weakly connected to a sparse periphery, and an alternative structure in which the core is strongly connected both within itself and to the periphery. Networks vary in whether they are better represented by one type of structure or the other. We also observe structures that are a hybrid between core-periphery structure and community structure, in which networks have a set of non-overlapping cores that correspond roughly to communities, surrounded by a single undifferentiated periphery. Computer code implementing our methods is available.Comment: code available: https://github.com/apolanco115/hc

    Insulin-like growth factor 1 signaling in motor neuron and polyglutamine diseases: From molecular pathogenesis to therapeutic perspectives

    Get PDF
    The pleiotropic peptide insulin-like growth factor 1 (IGF-I) regulates human body homeostasis and cell growth. IGF-I activates two major signaling pathways, namely phosphoinositide-3-kinase (PI3K)/protein kinase B (PKB/Akt) and Ras/extracellular signal-regulated kinase (ERK), which contribute to brain development, metabolism and function as well as to neuronal maintenance and survival. In this review, we discuss the general and tissue-specific effects of the IGF-I pathways. In addition, we present a comprehensive overview examining the role of IGF-I in neurodegenerative diseases, such as spinal and muscular atrophy, amyotrophic lateral sclerosis, and polyglutamine diseases. In each disease, we analyze the disturbances of the IGF-I pathway, the modification of the disease protein by IGF-I signaling, and the therapeutic strategies based on the use of IGF-I developed to date. Lastly, we highlight present and future considerations in the use of IGF-I for the treatment of these disorders

    Dynamic wavelet correlation analysis for multivariate climate time series

    Get PDF
    The wavelet local multiple correlation (WLMC) is introduced for the first time in the study of climate dynamics inferred from multivariate climate time series. To exemplify the use of WLMC with real climate data, we analyse Last Millennium (LM) relationships among several large‑scale reconstructed climate variables characterizing North Atlantic: i.e. sea surface temperatures (SST) from the tropical cyclone main developmental region (MDR), the El Niño‑Southern Oscillation (ENSO), the North Atlantic Multidecadal Oscillation (AMO), and tropical cyclone counts (TC). We examine the former three large‑scale variables because they are known to influence North Atlantic tropical cyclone activity and because their underlying drivers are still under investigation. WLMC results obtained for these multivariate climate time series suggest that: (1) MDRSST and AMO show the highest correlation with each other and with respect to the TC record over the last millennium, and: (2) MDRSST is the dominant climate variable that explains TC temporal variability. WLMC results confirm that this method is able to capture the most fundamental information contained in multivariate climate time series and is suitable to investigate correlation among climate time series in a multivariate contextJ.M.P.M was funded by the PIC 444/18 – EU Interreg project MOSES (EAPA 224/2016), FEDER funds and the SEPE (Spanish Public Service of Employment). J.F.M. acknowledges research funding received from UPV/EHU Econometrics Research Group (Basque Government Dpt. of Education grant IT-1359-19) and Spanish Ministry of Economy and Business (grant MTM2016-74931-P)

    Controle da podridão cinzenta da maçã por produtos naturais biologicamente ativos

    Get PDF
    Indexación: Web of Science; ScieloBiorend SC (chitosan), BC-1000 EC (grapefruit extract plus bioflavonoids) and ECO-100 SC (bioflavonoids plus organic acids, citric phytoalexins, fatty acids, glycerides and sugars), respectively, suppressed grey rot of apple caused by B. cinerea by 80.1%, 79.0% and 76.5% when used as post-harvest treatments under controlled conditions. When applied as combined pre- and post-harvest treatments Biorend SC inhibited fruit rot by 49.9 %, while BC-1000 EC and ECO-100 SC were ineffective. None of the products inhibited fruit rot when applied as pre-harvest treatments under controlled conditions or as post-harvest treatments under commercial conditions. The algal polysaccharide ulvan used in post-harvest treatments suppressed grey rot by 56.0% under controlled conditions, but had no inhibitory effect on combined pre- and post-harvest treatments. The inability of products to activate defense mechanisms (chitinase and peroxidase) of fruits was consistent with the unsuccessful control of rot by pre-harvest treatment. The results suggest that the natural products used have potential for use in integrated management of Botrytis rot when applied after harvest.Biorend SC (quitosana), BC-1000 EC (extrato de toranja mais flavonóides), e ECO-100 SC (bioflavonóides mais ácidos orgânicos, fitoalexinas cítricas, ácidos graxos glicerídeos e açúcares) inibiram em 80,1%, 79,0% e 76,5%, respectivamente, a podridão causada por Botrytis cinerea quando utilizados no tratamento pós-colheita de frutos de maçã sob condições controladas.Tratamento combinado de Biorend SC, com aplicação tanto em pré como no pós-colheita, proporcionou 49,9% de inibição da podridão, enquanto BC-1000 e ECO-100 EC não foram efetivos. Nenhum desses produtos inibiu a podridão cinzenta, quando utilizados em tratamento de pré-colheita em condições controladas ou em tratamento de pós-colheita em condições comerciais. O polissacarídeo algal ulvana, utilizado nos tratamentos de pós-colheita, reduziu em 56% a podridão cinzenta das maçãs em condições controladas, mas não teve efeito inibitório nos tratamentos combinados de pré e pós-colheita. A incapacidade dos produtos em ativar mecanismos de defesa (quitinases e peroxidases) nos frutos, após o tratamento em pré-colheita, foi consistente com a falta de controle da podridão nesse tipo de ensaio. Pelos resultados, sugere-se que os produtos naturais utilizados apresentam potencial para a utilização no manejo integrado da podridão de Botrytis quando aplicados em pós-colheita.http://ref.scielo.org/kcxb9

    A reconstructed database of historic bluefin tuna captures in the Gibraltar Strait and Western Mediterranean

    Get PDF
    This data paper presents a reconstruction of a compilation of a small but consistent database of historical capture records of bluefin tuna (Thunnus thynnus; BFT hereafter) from the Gibraltar Strait and Western Mediterranean (Portugal, Spain and Italy). The compilation come from diverse historical and documentary sources and span the time interval from 1525 to 1936 covering a period of 412 years. There is a total of 3074 datum, which reach up to 67.83% of the total implying a 32.17% of missing data. However, we have only reconstructed the captures for the time interval 1700 1936 and we provide these reconstructions only for this time interval and for 9 out of 11 series due to the scarcity and inhomogeneity of the two oldest capture time series. This reconstructed database provides an invaluable opportunity for fisheries and marine research as well as for multidisciplinary research in climate change. © 2017 The AuthorsJ.M.P.M. was funded by a Basque Government post-doctoral fellowship. A. M. Caballero-Alfonso was funded by the Spanish Ministry of Education, Culture and Sports

    Legacies of past forest management determine current responses to severe drought events of conifer species in the Romanian Carpathians

    Get PDF
    Worldwide increases in droughts- and heat-waves-associated tree mortality events are destabilizing the future of many forests and the ecosystem services they provide. Along with climate, understanding the impact of the legacies of past forest management is key to better explain current responses of different tree species to climate change. We studied tree mortality events that peaked in 2012 affecting one native (silver fir; growing within its natural distribution range) and two introduced (black pine and Scots; growing outside their natural distribution range) conifer species from the Romanian Carpathians. The three conifers were compared in terms of mortality events, growth trends, growth resilience to severe drought events, climate-growth relationships, and regeneration patterns. The mortality rates of the three species were found to be associated with severe drought events. Nevertheless, the native silver fir seems to undergo a self-thinning process, while the future of the remaining living black pine and Scots pine trees is uncertain as they register significant negative growth trends. Overall, the native silver fir showed a higher resilience to severe drought events than the two introduced pine species. Furthermore, and unlike the native silver fir, black pine and Scots pine species do not successfully regenerate. A high diversity of native broadleaf species sprouts and develops instead under them suggesting that we might be witnessing a process of ecological succession, with broadleaves recovering their habitats. As native species seem to perform better in terms of resilience and regeneration than introduced species, the overall effect of the black pine and Scots pine mortality might be compensated. Legacies of past forest management should be taken into account in order to better understand current responses of different tree species to ongoing climate change. © 2020 Elsevier B.V.We thank the Forest District staff of Sacele, Kronstadt, Rasnov, Teliu, Codlea, and Intorsura Buzaului for all their support and for giving us access to the Forest Management Plans. This work was financed by the NATIvE ( PN-III-P1-1.1-PD-2016-0583 ) and TreeMoris ( PN-II-RU-TE-2014-4-0791 ) projects through UEFISCDI (link; Romanian Ministry of Education and Research ) and supported by the BERC 2018-2021 ( Basque Government ), and BC3 María de Maeztu Excellence Accreditation 2018-2022, Ref. MDM-2017-0714 ( Spanish Ministry of Science, Innovation and Universities ). We also thank Antonio Gazol for interesting discussions on the study and Ionela-Mirela Medrea, Andrei Apafaian, Maria Băluţ, and Florin Dinulică for assistance during field and laboratory campaigns. Silver fir, black pine, and Scots pine figures included in the graphical abstract are reproduced with the authorization of the designer Luiza Anamaria Pop (©2020) who drew the three conifer species and processed the drawings in Adobe Illustrator® CS5 (v. 15.0.0)

    Analysis of colorectal cancers in British Bangladeshi identifies early onset, frequent mucinous histotype and a high prevalence of RBFOX1 deletion

    Get PDF
    PMCID: PMC3544714This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Quantum Films Adsorbed on Graphite: Third and Fourth Helium Layers

    Full text link
    Using a path-integral Monte Carlo method for simulating superfluid quantum films, we investigate helium layers adsorbed on a substrate consisting of graphite plus two solid helium layers. Our results for the promotion densities and the dependence of the superfluid density on coverage are in agreement with experiment. We can also explain certain features of the measured heat capacity as a function of temperature and coverage.Comment: 13 pages in the Phys. Rev. two-column format, 16 Figure

    Hot spring arsenic distribution in the Andes Cordillera (18-52oS)

    Get PDF
    1 página.-- Resumen presentado en el 23rd International Applied Geochemistry Symposium (IAGS), Oviedo, 14-19 Jun. 2007.-- Edited by Jorge Loredo Pérez.One of the most extensive areas around the world where the low quality of groundwater due to the presence of high concentrations of arsenic of natural origin is a major concern is Argentina-Chile. The exhaustive knowledge of the geological, hydrogeological, and geochemical setting can be very effective to define an alternative strategy to mitigate the arsenic problem in water. The magnitude and extension of the arsenic affected areas is not well known. In order to understand the source of the arsenic, the development of a database of thermal waters in the Andean region is in progress. We present in this work the assessment of more than 360 hot springs and wells located in the Andes between 14 and 52oS of latitude. This information comes from projects carried out by our team in the area and from references. The hot waters with higher concentrations of arsenic (50-30,000 μg/l) are mainly located in volcanic areas with hydrothermal activity of the Andes Cordillera between 14 and 28oS.Peer reviewe

    PIH32 WOMEN'S PREFERENCES FOR OVARIAN STIMULATING HORMONES IN THE TREATMENT OF INFERTILITY

    Get PDF
    corecore