130 research outputs found
Noncommutative field gas driven inflation
We investigate early time inflationary scenarios in an Universe filled with a
dilute noncommutative bosonic gas at high temperature. A noncommutative bosonic
gas is a gas composed of bosonic scalar field with noncommutative field space
on a commutative spacetime. Such noncommutative field theories was recently
introduced as a generalization of quantum mechanics on a noncommutative
spacetime. As key features of these theories are Lorentz invariance violation
and CPT violation. In the present study we use a noncommutative bosonic field
theory that besides the noncommutative parameter shows up a further
parameter . This parameter controls the range of the
noncommutativity and acts as a regulator for the theory. Both parameters play a
key role in the modified dispersion relations of the noncommutative bosonic
field, leading to possible striking consequences for phenomenology. In this
work we obtain an equation of state for the
noncommutative bosonic gas relating pressure and energy density , in
the limit of high temperature. We analyse possible behaviours for this gas
parameters , and , so that , which
is the region where the Universe enters an accelerated phase.Comment: Reference added. Version to appear in Journal of Cosmology and
Astroparticle Physics - JCA
Phylogeny and biogeography of Ceiba Mill. (Malvaceae, Bombacoideae)
The Neotropics is the most species-rich area in the world, and the mechanisms that generated and maintain its biodiversity are still debated. This paper contributes to the debate by investigating the evolutionary and biogeographic history of the genus Ceiba Mill. (Malvaceae, Bombacoideae). Ceiba comprises 18 mostly Neotropical species, largely endemic to two major biomes, seasonally dry tropical forests (SDTFs) and rain forests. Its species are among the most characteristic elements of Neotropical SDTF, one of the most threatened biomes in the tropics. Phylogenetic analyses of DNA sequence data (from the nuclear ribosomal internal transcribed spacers [nrITS] for 30 accessions representing 14 species of Ceiba) recovered the genus as monophyletic. The phylogeny showed geographic and ecological structure in three main clades: (i) a rain forest lineage of nine accessions of C. pentandra sister to the remaining species; (ii) a highly supported clade composed of C. schottii and C. aesculifolia from Central American and Mexican SDTF, plus two accessions of C. samauma from semi-humid, inter Andean valleys in Peru; and (iii) a highly supported South American SDTF clade including 10 species showing little sequence variation. Within this South American SDTF clade, no species represented by multiple accessions were resolved as monophyletic. We demonstrate that the patterns of species age, monophyly, and geographic structure previously reported for SDTF species within the Leguminosae family are not shared by Ceiba, suggesting that further phylogenetic studies of unrelated groups are required to understand general patterns
Whipple's Disease With Neurological Manifestations: Case Report.
Whipple's disease (WD) is an uncommon multisystem condition caused by the bacillus Tropheryma whipplei. Central nervous system involvement is a classical feature of the disease observed in 20 to 40% of the patients. We report the case of a 62 year old man with WD that developed neurological manifestations during its course, and discuss the most usual signs and symptoms focusing on recent diagnostic criteria and novel treatment regimens.62342-
Phylogenomic analysis of 997 nuclear genes reveals the need for extensive generic re-delimitation in Caesalpinioideae (Leguminosae)
Subfamily Caesalpinioideae with ca. 4,600 species in 152 genera is the second-largest subfamily of legumes (Leguminosae) and forms an ecologically and economically important group of trees, shrubs and lianas with a pantropical distribution. Despite major advances in the last few decades towards aligning genera with clades across Caesalpinioideae, generic delimitation remains in a state of considerable flux, especially across the mimosoid clade. We test the monophyly of genera across Caesalpinioideae via phylogenomic analysis of 997 nuclear genes sequenced via targeted enrichment (Hybseq) for 420 species and 147 of the 152 genera currently recognised in the subfamily. We show that 22 genera are non-monophyletic or nested in other genera and that non-monophyly is concentrated in the mimosoid clade where ca. 25% of the 90 genera are found to be non-monophyletic. We suggest two main reasons for this pervasive generic non-monophyly: (i) extensive morphological homoplasy that we document here for a handful of important traits and, particularly, the repeated evolution of distinctive fruit types that were historically emphasised in delimiting genera and (ii) this is an artefact of the lack of pantropical taxonomic syntheses and sampling in previous phylogenies and the consequent failure to identify clades that span the Old World and New World or conversely amphi-Atlantic genera that are non-monophyletic, both of which are critical for delimiting genera across this large pantropical clade. Finally, we discuss taxon delimitation in the phylogenomic era and especially how assessing patterns of gene tree conflict can provide additional insights into generic delimitation. This new phylogenomic framework provides the foundations for a series of papers reclassifying genera that are presented here in Advances in Legume Systematics (ALS) 14 Part 1, for establishing a new higher-level phylogenetic tribal and clade-based classification of Caesalpinioideae that is the focus of ALS14 Part 2 and for downstream analyses of evolutionary diversification and biogeography of this important group of legumes which are presented elsewhere
Hybrid capture of 964 nuclear genes resolves evolutionary relationships in the mimosoid legumes and reveals the polytomous origins of a large pantropical radiation
PREMISE
Targeted enrichment methods facilitate sequencing of hundreds of nuclear loci to enhance phylogenetic resolution and elucidate why some parts of the “tree of life” are difficult (if not impossible) to resolve. The mimosoid legumes are a prominent pantropical clade of ~3300 species of woody angiosperms for which previous phylogenies have shown extensive lack of resolution, especially among the species‐rich and taxonomically challenging ingoids.
METHODS
We generated transcriptomes to select low‐copy nuclear genes, enrich these via hybrid capture for representative species of most mimosoid genera, and analyze the resulting data using de novo assembly and various phylogenomic tools for species tree inference. We also evaluate gene tree support and conflict for key internodes and use phylogenetic network analysis to investigate phylogenetic signal across the ingoids.
RESULTS
Our selection of 964 nuclear genes greatly improves phylogenetic resolution across the mimosoid phylogeny and shows that the ingoid clade can be resolved into several well‐supported clades. However, nearly all loci show lack of phylogenetic signal for some of the deeper internodes within the ingoids.
CONCLUSIONS
Lack of resolution in the ingoid clade is most likely the result of hyperfast diversification, potentially causing a hard polytomy of six or seven lineages. The gene set for targeted sequencing presented here offers great potential to further enhance the phylogeny of mimosoids and the wider Caesalpinioideae with denser taxon sampling, to provide a framework for taxonomic reclassification, and to study the ingoid radiation
Precipitation is the main axis of tropical phylogenetic turnover across space and time
Early natural historians – Compte de Buffon, von Humboldt and De Candolle – established ecology and geography as two principal axes determining the distribution of groups of organisms, laying the foundations for biogeography over the subsequent 200 years, yet the relative importance of these two axes remains unresolved. Leveraging phylogenomic and global species distribution data for Mimosoid legumes, an pantropical plant clade of 3,400 species, we show that the water availability gradient from deserts to rainforests dictates turnover of lineages within continents across the tropics. We demonstrate that 95% of speciation occurs within a precipitation niche, showing profound phylogenetic niche conservatism, and that lineage turnover boundaries coincide with isohyets of precipitation. We reveal similar patterns on different continents, implying that evolution and dispersal follow universal processes.Fil: Ringelberg, Jens J. University of Zurich. Department of Systematic and Evolutionary Botany; SuizaFil: Koenen, Erik J.M. University of Zurich. Department of Systematic and Evolutionary Botany; Suiza. Université Libre de Bruxelles. Faculté des Sciences. Evolutionary Biology & Ecology; BélgicaFil: Sauter, Benjamín. University of Zurich. Department of Systematic and Evolutionary Botany; SuizaFil: Aebli, Anahita. University of Zurich. Department of Systematic and Evolutionary Botany; Suiza. Abteling Umweltschutz und Energie. Departement Bau und Umwelt; SuizaFil: Rando, Juliana G. Universidade Federal do Oeste da Bahia. Centro das Ciências Biológicas e da Saúde. Programa de Pós Graduação em Ciências Ambientais; BrasilFil: Iganci, João R. Universidade Federal de Pelotas. Campus Universitário Capão do Leão. Instituto de Biologia; Brasil. Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Botânica; BrasilFil: de Queiroz, Luciano P. Universidade Estadual de Feira de Santana. Departamento Ciências Biológicas; BrasilFil: Murphy, Daniel J. Royal Botanic Gardens Victoria: AustraliaFil: Gaudeul, Myriam. Institut de Systématique, Evolution, Biodiversité (ISYEB), MNHN-CNRS-SU-EPHE-UA: FranciaFil: Bruneau, Anne. Université de Montréal. Institut de Recherche en Biologie Végétale and Département de Sciences Biologiques; CanadáFil: Luckow, Melissa. Cornell University. School of Integrative Plant Science. Plant Biology Section; Estados UnidosFil: Morales, Matias. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Morón. Facultad de Agronomía y Ciencias Agroalimentarias; Argentin
New segregates from the Neotropical genus Stryphnodendron (Leguminosae, Caesalpinioideae, mimosoid clade)
Non-monophyly is a prominent issue in mimosoid legumes, even in some of the less speciose genera such as the neotropical genus Stryphnodendron. This genus includes 35 species occurring from Nicaragua to Southern Brazil mostly in humid forests and savannas. Previous taxonomic studies of Stryphnodendron have highlighted morphologically distinct groups within the genus, recognized by differences on leaves (number of pinnae and size of leaflets), inflorescences (a simple or compound thyrse), and fruit types (legume, nucoid legume or follicle). Recent phylogenetic analyses have confirmed the non-monophyly of Stryphnodendron, supporting the recognition of three independent and morphologically well-delimited genera. Here we re-circumscribe Stryphnodendron and propose the two new genera Gwilymia and Naiadendron. In addition, we also provide an updated taxonomic account of the closely related genus Microlobius, including the proposal of a lectotype for the single species in the genus
BINGO-ABDUS: a radiotelescope to unveil the dark sector of the Universe
we review the Baryon Acoustic Oscillations from Integrated Neutral Gas
Observations (BINGO) telescope, an international collaboration, led by Brazil
and China, aiming to explore the Universe history through integrated
post-reionization 21cm signals and fast radio emissions. For identifying
individually fast radio sources, the Advanced Bingo Dark Universe Studies
(ABDUS) project has been proposed and developed and will combine the current
BINGO construction with the main single-dish telescope and stations of
phased-array and outrigger.Comment: 23 pages, work presented in Syros, Greece, September 2022, to appear
in Springe
Holographic Description of Heavy-Quark Potentials in an Inflationary Braneworld Scenario
We study heavy-quark potential in an inflationary braneworld scenario. The
scenario we consider is an (Euclidean) inflating braneworld embedded in
a static Euclidean . Using gauge/gravity duality we obtain a confining
phase depending on the ratio between the Hubble parameter in the braneworld
and the brane tension .Comment: 16 pages. Minor modifications. To appear in JHE
Mecanismos de transferência de massa na desidratação osmótica de goiaba em soluções de sacarose, sucralose e açúcar invertido
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