Cavity and replica methods for the spectral density of sparse symmetric random matrices

We review the problem of how to compute the spectral density of sparse symmetric random matrices, i.e. weighted adjacency matrices of undirected graphs. Starting from the Edwards-Jones formula, we illustrate the milestones of this line of research, including the pioneering work of Bray and Rodgers using replicas. We focus first on the cavity method, showing that it quickly provides the correct recursion equations both for single instances and at the ensemble level. We also describe an alternative replica solution that proves to be equivalent to the cavity method. Both the cavity and the replica derivations allow us to obtain the spectral density via the solution of an integral equation for an auxiliary probability density function. We show that this equation can be solved using a stochastic population dynamics algorithm, and we provide its implementation. In this formalism, the spectral density is naturally written in terms of a superposition of local contributions from nodes of given degree, whose role is thoroughly elucidated. This paper does not contain original material, but rather gives a pedagogical overview of the topic. It is indeed addressed to students and researchers who consider entering the field. Both the theoretical tools and the numerical algorithms are discussed in detail, highlighting conceptual subtleties and practical aspects.Comment: 52 pag., 5 fig. Typos fixed. Submission to SciPos

Complete mitochondrial sequences from Mesolithic Sardinia

Little is known about the genetic prehistory of Sardinia because of the scarcity of pre-Neolithic human remains. From a genetic perspective, modern Sardinians are known as genetic outliers in Europe, showing unusually high levels of internal diversity and a close relationship to early European Neolithic farmers. However, how far this peculiar genetic structure extends and how it originated was to date impossible to test. Here we present the first and oldest complete mitochondrial sequences from Sardinia, dated back to 10,000 yBP. These two individuals, while confirming a Mesolithic occupation of the island, belong to rare mtDNA lineages, which have never been found before in Mesolithic samples and that are currently present at low frequencies not only in Sardinia, but in the whole Europe. Preliminary Approximate Bayesian Computations, restricted by biased reference samples for Mesolithic Sardinia (the two typed samples) and Neolithic Europe (limited to central and north European sequences), suggest that the first inhabitants of the island have had a small or negligible contribution to the present-day Sardinian population, which mainly derives its genetic diversity from continental migration into the island by Neolithic times

Molecular and Functional Characterization of Three Different Postzygotic Mutations in PIK3CA-Related Overgrowth Spectrum (PROS) Patients: Effects on PI3K/AKT/mTOR Signaling and Sensitivity to PIK3 Inhibitors

BACKGROUND PIK3CA-related overgrowth spectrum (PROS) include a group of disorders that affect only the terminal portion of a limb, such as type I macrodactyly, and conditions like fibroadipose overgrowth (FAO), megalencephaly-capillary malformation (MCAP) syndrome, congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome and Hemihyperplasia Multiple Lipomatosis (HHML). Heterozygous postzygotic PIK3CA mutations are frequently identified in these syndromes, while timing and tissue specificity of the mutational event are likely responsible for the extreme phenotypic variability observed. METHODS: We carried out a combination of Sanger sequencing and targeted deep sequencing of genes involved in the PI3K/AKT/mTOR pathway in three patients (1 MCAP and 2 FAO) to identify causative mutations, and performed immunoblot analyses to assay the phosphorylation status of AKT and P70S6K in affected dermal fibroblasts. In addition, we evaluated their ability to grow in the absence of serum and their response to the PI3K inhibitors wortmannin and LY294002 in vitro. RESULTS AND CONCLUSION: Our data indicate that patients' cells showed constitutive activation of the PI3K/Akt pathway. Of note, PI3K pharmacological blockade resulted in a significant reduction of the proliferation rate in culture, suggesting that inhibition of PI3K might prove beneficial in future therapies for PROS patients

Functional evidence of mTORβ splice variant involvement in the pathogenesis of congenital heart defects

mTOR dysregulation has been described in pathological conditions, such as cardiovascular and overgrowth disorders. Here we report on the first case of a patient with a complex congenital heart disease and an interstitial duplication in the short arm of chromosome 1, encompassing part of the mTOR gene. Our results suggest that an intragenic mTOR microduplication might play a role in the pathogenesis of non-syndromic congenital heart defects (CHDs) due to an upregulation of mTOR/Rictor and consequently an increased phosphorylation of PI3K/AKT and MEK/ERK signaling pathways in patient-derived amniocytes. This is the first report which shows a causative role of intragenic mTOR microduplication in the etiology of an isolated complex CHD

A western route of prehistoric human migration from Africa into the Iberian Peninsula

Being at the western fringe of Europe, Iberia had a peculiar prehistory and a complex pattern of Neolithization. A few studies, all based on modern populations, reported the presence of DNA of likely African origin in this region, generally concluding it was the result of recent gene flow, probably during the Islamic period. Here, we provide evidence of much older gene flow from Africa to Iberia by sequencing whole genomes from four human remains from northern Portugal and southern Spain dated around 4000 years BP (from the Middle Neolithic to the Bronze Age). We found one of them to carry an unequivocal sub-Saharan mitogenome of most probably West or West-Central African origin, to our knowledge never reported before in prehistoric remains outside Africa. Our analyses of ancient nuclear genomes show small but significant levels of sub-Saharan African affinity in several ancient Iberian samples, which indicates that what we detected was not an occasional individual phenomenon, but an admixture event recognizable at the population level. We interpret this result as evidence of an early migration process from Africa into the Iberian Peninsula through a western route, possibly across the Strait of Gibraltar

Airships: A New Horizon for Science

The "Airships: A New Horizon for Science" study at the Keck Institute for Space Studies investigated the potential of a variety of airships currently operable or under development to serve as observatories and science instrumentation platforms for a range of space, atmospheric, and Earth science. The participants represent a diverse cross-section of the aerospace sector, NASA, and academia. Over the last two decades, there has been wide interest in developing a high altitude, stratospheric lighter-than-air (LTA) airship that could maneuver and remain in a desired geographic position (i.e., "station-keeping") for weeks, months or even years. Our study found considerable scientific value in both low altitude (< 40 kft) and high altitude (> 60 kft) airships across a wide spectrum of space, atmospheric, and Earth science programs. Over the course of the study period, we identified stratospheric tethered aerostats as a viable alternative to airships where station-keeping was valued over maneuverability. By opening up the sky and Earth's stratospheric horizon in affordable ways with long-term flexibility, airships allow us to push technology and science forward in a project-rich environment that complements existing space observatories as well as aircraft and high-altitude balloon missions.Comment: This low resolution version of the report is 8.6 MB. For the high resolution version see: http://kiss.caltech.edu/study/airship

Fungal Planet description sheets: 785– 867

Novel species of fungi described in this study include those from various countries as follows: Angola, Gnomoniopsis angolensis and Pseudopithomyces angolensis on unknown host plants. Australia, Dothiora corymbiae on Corymbia citriodora, Neoeucasphaeria eucalypti (incl. Neoeucasphaeria gen. nov.)on Eucalyptus sp., Fumagopsis stellae on Eucalyptus sp., Fusculina eucalyptorum (incl. Fusculinaceae fam. nov.) on Eucalyptus socialis, Harknessia corymbiicola on Corymbia maculata, Neocelosporium eucalypti (incl. Neocelosporium gen. nov., Neocelosporiaceae fam. nov. and Neocelosporiales ord. nov.) on Eucalyptus cyanophylla, Neophaeomoniella corymbiae on Corymbia citriodora, Neophaeomoniella eucalyptigena on Eucalyptus pilularis, Pseudoplagiostoma corymbiicola on Corymbia citriodora, Teratosphaeria gracilis on Eucalyptus gracilis, Zasmidium corymbiae on Corymbia citriodora. Brazil, Calonectria hemileiae on pustules of Hemileia vastatrix formed on leaves of Coffea arabica, Calvatia caatinguensis on soil, Cercospora solani-betacei on Solanum betaceum, Clathrus natalensis on soil, Diaporthe poincianellae on Poincianella pyramidalis, Geastrum piquiriunense on soil, Geosmithia carolliae on wing of Carollia perspicillata, Henningsia resupinata on wood, Penicillium guaibinense from soil, Periconia caespitosa from leaf litter, Pseudocercospora styracina on Styrax sp., Simplicillium filiforme as endophyte from Citrullus lanatus, Thozetella pindobacuensis on leaf litter, Xenosonderhenia coussapoae on Coussapoa floccosa. Canary Islands (Spain), Orbilia amarilla on Euphorbia canariensis. Cape Verde Islands, Xylodon jacobaeus on Eucalyptus camaldulensis. Chile, Colletotrichum arboricola on Fuchsia magellanica. Costa Rica, Lasiosphaeria miniovina ontreebranch. Ecuador, Ganoderma chocoense ontreetrunk. France, Neofitzroyomyces nerii (incl. Neofitzroyomyces gen. nov.) on Nerium oleander. Ghana, Castanediella tereticornis on Eucalyptus tereticornis, Falcocladium africanum on Eucalyptus brassiana, Rachicladosporium corymbiae on Corymbia citriodora. Hungary, Entoloma silvae-frondosae in Carpinus betulus-Pinus sylvestris mixedforest. Iran, Pseudopyricularia persiana on Cyperus sp. Italy, Inocybe roseascens onsoilinmixedforest. Laos, Ophiocordyceps houaynhangensis on Coleoptera larva. Malaysia, Monilochaetes melastomae on Melastoma sp. Mexico, Absidia terrestris fromsoil. Netherlands, Acaulium pannemaniae, Conioscypha boutwelliae, Fusicolla septimanifiniscientiae, Gibellulopsis simonii, Lasionectria hilhorstii, Lectera nordwiniana, Leptodiscella rintelii, Parasarocladium debruynii and Sarocladium dejongiae (incl. Sarocladiaceae fam. nov.) fromsoil. New Zealand, Gnomoniopsis rosae on Rosa sp. and Neodevriesia metrosideri on Metrosideros sp. Puerto Rico, Neodevriesia coccolobae on Coccoloba uvifera, Neodevriesia tabebuiae and Alfaria tabebuiae on Tabebuia chrysantha . Russia, Amanita paludosa on bogged soil in mixed deciduous forest, Entoloma tiliae in forest of Tilia × europaea, Kwoniella endophytica on Pyrus communis. South Africa, Coniella diospyri on Diospyros mespiliformis, Neomelanconiella combreti (incl. Neomelanconiellaceae fam. nov. and Neomelanconiella gen. nov.)on Combretum sp., Polyphialoseptoria natalensis on unidentified plant host, Pseudorobillarda bolusanthi on Bolusanthus speciosus, Thelonectria pelargonii on Pelargonium sp. Spain, Vermiculariopsiella lauracearum and Anungitopsis lauri on Laurus novocanariensis, Geosmithia xerotolerans from a darkened wall of a house, Pseudopenidiella gallaica on leaf litter. Thailand, Corynespora thailandica on wood, Lareunionomyces loeiensis on leaf litter, Neocochlearomyces chromolaenae (incl. Neocochlearomyces gen. nov.) on Chromolaena odorata, Neomyrmecridium septatum (incl. Neomyrmecridium gen. nov .), Pararamichloridium caricicola on Carex sp., Xenodactylaria thailandica (incl. Xenodactylariaceae fam. nov. and Xenodactylaria gen. nov.), Neomyrmecridium asiaticum and Cymostachys thailandica fromunidentifiedvine. USA, Carolinigaster bonitoi (incl. Carolinigaster gen. nov.)fromsoil, Penicillium fortuitum from house dust, Phaeotheca shathenatiana (incl. Phaeothecaceae fam. nov.) from twig and cone litter, Pythium wohlseniorum from stream water, Superstratomyces tardicrescens from human eye, Talaromyces iowaense from officeair. Vietnam, Fistulinella olivaceoalba onsoil. Morphological and culture characteristics along with DNA barcodes are provided Novel species of fungi described in this study include those from various countries as follows: Angola, Gnomoniopsis angolensis and Pseudopithomyces angolensis on unknown host plants. Australia, Dothiora corymbiae on Corymbia citriodora, Neoeucasphaeria eucalypti (incl. Neoeucasphaeria gen. nov.)on Eucalyptus sp., Fumagopsis stellae on Eucalyptus sp., Fusculina eucalyptorum (incl. Fusculinaceae fam. nov.) on Eucalyptus socialis, Harknessia corymbiicola on Corymbia maculata, Neocelosporium eucalypti (incl. Neocelosporium gen. nov., Neocelosporiaceae fam. nov. and Neocelosporiales ord. nov.) on Eucalyptus cyanophylla, Neophaeomoniella corymbiae on Corymbia citriodora, Neophaeomoniella eucalyptigena on Eucalyptus pilularis, Pseudoplagiostoma corymbiicola on Corymbia citriodora, Teratosphaeria gracilis on Eucalyptus gracilis, Zasmidium corymbiae on Corymbia citriodora. Brazil, Calonectria hemileiae on pustules of Hemileia vastatrix formed on leaves of Coffea arabica, Calvatia caatinguensis on soil, Cercospora solani-betacei on Solanum betaceum, Clathrus natalensis on soil, Diaporthe poincianellae on Poincianella pyramidalis, Geastrum piquiriunense on soil, Geosmithia carolliae on wing of Carollia perspicillata, Henningsia resupinata on wood, Penicillium guaibinense from soil, Periconia caespitosa from leaf litter, Pseudocercospora styracina on Styrax sp., Simplicillium filiforme as endophyte from Citrullus lanatus, Thozetella pindobacuensis on leaf litter, Xenosonderhenia coussapoae on Coussapoa floccosa. Canary Islands (Spain), Orbilia amarilla on Euphorbia canariensis. Cape Verde Islands, Xylodon jacobaeus on Eucalyptus camaldulensis. Chile, Colletotrichum arboricola on Fuchsia magellanica. Costa Rica, Lasiosphaeria miniovina ontreebranch. Ecuador, Ganoderma chocoense ontreetrunk. France, Neofitzroyomyces nerii (incl. Neofitzroyomyces gen. nov.) on Nerium oleander. Ghana, Castanediella tereticornis on Eucalyptus tereticornis, Falcocladium africanum on Eucalyptus brassiana, Rachicladosporium corymbiae on Corymbia citriodora. Hungary, Entoloma silvae-frondosae in Carpinus betulus-Pinus sylvestris mixedforest. Iran, Pseudopyricularia persiana on Cyperus sp. Italy, Inocybe roseascens onsoilinmixedforest. Laos, Ophiocordyceps houaynhangensis on Coleoptera larva. Malaysia, Monilochaetes melastomae on Melastoma sp. Mexico, Absidia terrestris fromsoil. Netherlands, Acaulium pannemaniae, Conioscypha boutwelliae, Fusicolla septimanifiniscientiae, Gibellulopsis simonii, Lasionectria hilhorstii, Lectera nordwiniana, Leptodiscella rintelii, Parasarocladium debruynii and Sarocladium dejongiae (incl. Sarocladiaceae fam. nov.) fromsoil. New Zealand, Gnomoniopsis rosae on Rosa sp. and Neodevriesia metrosideri on Metrosideros sp. Puerto Rico, Neodevriesia coccolobae on Coccoloba uvifera, Neodevriesia tabebuiae and Alfaria tabebuiae on Tabebuia chrysantha. Russia, Amanita paludosa on bogged soil in mixed deciduous forest, Entoloma tiliae in forest of Tilia × europaea, Kwoniella endophytica on Pyrus communis. South Africa, Coniella diospyri on Diospyros mespiliformis, Neomelanconiella combreti (incl. Neomelanconiellaceae fam. nov. and Neomelanconiella gen. nov.)on Combretum sp., Polyphialoseptoria natalensis on unidentified plant host, Pseudorobillarda bolusanthi on Bolusanthus speciosus, Thelonectria pelargonii on Pelargonium sp. Spain, Vermiculariopsiella lauracearum and Anungitopsis lauri on Laurus novocanariensis, Geosmithia xerotolerans from a darkened wall of a house, Pseudopenidiella gallaica on leaf litter. Thailand, Corynespora thailandica on wood, Lareunionomyces loeiensis on leaf litter, Neocochlearomyces chromolaenae (incl. Neocochlearomyces gen. nov.) on Chromolaena odorata, Neomyrmecridium septatum (incl. Neomyrmecridium gen. nov .), Pararamichloridium caricicola on Carex sp., Xenodactylaria thailandica (incl. Xenodactylariaceae fam. nov. and Xenodactylaria gen. nov.), Neomyrmecridium asiaticum and Cymostachys thailandica fromunidentifiedvine. USA, Carolinigaster bonitoi (incl. Carolinigaster gen. nov.)fromsoil, Penicillium fortuitum from house dust, Phaeotheca shathenatiana (incl. Phaeothecaceae fam. nov.) from twig and cone litter, Pythium wohlseniorum from stream water, Superstratomyces tardicrescens from human eye, Talaromyces iowaense from officeair. Vietnam, Fistulinella olivaceoalba onsoil. Morphological and culture characteristics along with DNA barcodes are provided

Avances en teledetección para la prevención y detección temprana de Xylella fastidiosa en el marco de los proyectos H2020 POnTE y XF-ACTORS.

Informational article of the tasks carried out in WP6 of POnTE and WP3 of XF-ACTORS in a professional Spanish magazin