1,581 research outputs found

    Modular vector fields attached to Dwork family: sl2(C)\mathfrak{sl}_2(\mathbb{C}) Lie algebra

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    We introduce an algebraic group G\sf G that acts from right on the moduli space T\textsf{T} of Calabi-Yau nn-folds arising from Dwork family enhanced with differential forms, and describe its Lie algebra Lie(G){\rm Lie}({\sf G}). We observe that Lie(G){\rm Lie}({\sf G}) together with a modular vector field R{\sf R} on T\textsf{T} generates another Lie algebra G\mathfrak{G}, called AMSY-Lie algebra, such that dimG=dimT\dim \mathfrak{G}=\dim {\sf T}. We find sl2(C)\mathfrak{sl}_2(\mathbb{C}) as a Lie subalgebra of G\mathfrak{G} that contains R\sf R.Comment: 20 page

    Time Explains Regional Richness Patterns within Clades More Often than Diversification Rates or Area

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    Most groups of organisms occur in multiple regions and have different numbers of species in different regions. These richness patterns are directly explained by speciation, extinction, and dispersal. Thus, regional richness patterns may be explained by differences in when regions were colonized (more time for speciation in regions colonized earlier), differences in how often they were colonized, or differences in diversification rates (speciation minus extinction) among regions (with diversification rates potentially influenced by area, climate, and/or many other variables). Few studies have tested all three factors, and most that did examined them only in individual clades. Here, we analyze a diverse set of 15 clades of plants and animals to test the causes of regional species richness patterns within clades. We find that time was the sole variable significantly explaining richness patterns in the best-fitting models for most clades (10/15), whereas time combined with other factors explained richness in all others. Time was the most important factor explaining richness in 13 of 15 clades, and it explained 72% of the variance in species richness among regions across all 15 clades (on average). Surprisingly, time was increasingly important in older and larger clades. In contrast, the area of the regions was relatively unimportant for explaining these regional richness patterns. A systematic review yielded 15 other relevant studies, which also overwhelmingly supported time over diversification rates (13 to 1, with one study supporting both diversification rates and time). Overall, our results suggest that colonization time is a major factor explaining regional-scale richness patterns within clades (e.g., families).National Natural Science Foundation of China [31670422, 31770402, 31770443]; Qinlan Project of Nanjing Normal University; Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) of Jiangsu Higher Education Institutions; US National Science Foundation [DEB 1655690]12 month embargo; Published online: 20 February 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

    Proofs of some Propositions of the semi-Intuitionistic Logic with Strong Negation

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    We offer the proofs that complete our article introducing the propositional calculus called semi-intuitionistic logic with strong negation.Comment: Contains proofs omitted, because of their extention, from an article published in Studia Logic

    Global patterns of diversification and species richness in amphibians.

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    abstract: Geographic patterns of species richness ultimately arise through the processes of speciation, extinction, and dispersal, but relatively few studies consider evolutionary and biogeographic processes in explaining these diversity patterns. One explanation for high tropical species richness is that many species-rich clades originated in tropical regions and spread to temperate regions infrequently and more recently, leaving little time for species richness to accumulate there (assuming similar rates of diversification in temperate and tropical regions). However, the major clades of anurans (frogs) and salamanders may offer a compelling counterexample. Most salamander families are predominately temperate in distribution, but the one primarily tropical clade (Bolitoglossinae) contains nearly half of all salamander species. Similarly, most basal clades of anurans are predominately temperate, but one largely tropical clade (Neobatrachia) contains ∼96% of anurans. In this article, I examine patterns of diversification in frogs and salamanders and their relationship to large-scale patterns of species richness in amphibians. I find that diversification rates in both frogs and salamanders increase significantly with decreasing latitude. These results may shed light on both the evolutionary causes of the latitudinal diversity gradient and the dramatic but poorly explained disparities in the diversity of living amphibian clades. Keywords: amphibians, biogeography, diversification, phylogeny, speciation, species richness. Explaining the underlying causes of large-scale patterns of species richness is an urgent challenge for ecologists and evolutionary biologists as global biodiversity is increasingly threatened. Some of these patterns, such as the tendency for species diversity to increase from the poles toward the equator, have been noted for centuries but have proved difficult to explain (e.g., Brown and Lomo-* E-mail: [email protected]. Many workers have found strong correlations between environmental variables and global diversity patterns and on this basis have considered climatic factors to be the primary explanation (e.g., In the 1990s, several evolutionary ecologists converged on a similar explanation for the high species richness of tropical regions, a hypothesis that integrates both evolutionary and ecological factors (e.g., The TCH has three main part

    Phylogenetic analyses reveal unexpected patterns in the evolution of reproductive modes in frogs

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    Understanding phenotypic diversity requires not only identification of selective factors that favor origins of derived states, but also factors that favor retention of primitive states. Anurans (frogs and toads) exhibit a remarkable diversity of reproductive modes that is unique among terrestrial vertebrates. Here, we analyze the evolution of these modes, using comparative methods on a phylogeny and matched life-history database of 720 species, including most families and modes. As expected, modes with terrestrial eggs and aquatic larvae often precede direct development (terrestrial egg, no tadpole stage), but surprisingly, direct development evolves directly from aquatic breeding nearly as often. Modes with primitive exotrophic larvae (feeding outside the egg) frequently give rise to direct developers, whereas those with nonfeeding larvae (endotrophic) do not. Similarly, modes with eggs and larvae placed in locations protected from aquatic predators evolve frequently but rarely give rise to direct developers. Thus, frogs frequently bypass many seemingly intermediate stages in the evolution of direct development. We also find significant associations between terrestrial reproduction and reduced clutch size, larger egg size, reduced adult size, parental care, and occurrence in wetter and warmer regions. These associations may help explain the widespread retention of aquatic eggs and larvae, and the overall diversity of anuran reproductive modes. © 2012 The Society for the Study of Evolution.Peer Reviewe

    Dale Goble as a Builder of Bridges

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    Ecological scientists and legal scholars think and talk in different ways. The “gulf of mutual incomprehension” that results can impede efforts to address shared problems. Dale Goble bridged this gulf by teaming with ecologists to interpret the Endangered Species Act and develop the concept of conservation-reliant species—species that require ongoing, long-term management to address the factors that threaten them. Most imperiled species are conservation reliant and conservation resources are limited. Meeting the long-term needs of conservation-reliant species will require the blending of ecological science, societal context, and law that Dale Goble has long promoted

    Solar Carbon Monoxide, Thermal Profiling, and the Abundances of C, O, and their Isotopes

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    A solar photospheric "thermal profiling" analysis is presented, exploiting the infrared rovibrational bands of carbon monoxide (CO) as observed with the McMath-Pierce Fourier transform spectrometer (FTS) at Kitt Peak, and from above the Earth's atmosphere by the Shuttle-borne ATMOS experiment. Visible continuum intensities and center-limb behavior constrained the temperature profile of the deep photosphere, while CO center-limb behavior defined the thermal structure at higher altitudes. The oxygen abundance was self consistently determined from weak CO absorptions. Our analysis was meant to complement recent studies based on 3-D convection models which, among other things, have revised the historical solar oxygen (and carbon) abundance downward by a factor of nearly two; although in fact our conclusions do not support such a revision. Based on various considerations, an oxygen abundance of 700+/-100 ppm (parts per million relative to hydrogen) is recommended; the large uncertainty reflects the model sensitivity of CO. New solar isotopic ratios also are reported for 13C, 17O, and 18O.Comment: 90 pages, 19 figures (some with parts "a", "b", etc.); to be published in the Astrophysical Journal Supplement

    Pengaruh Keaktifan Siswa terhadap Prestasi Belajar Mata Pelajaran Akuntansi Mengelola Kartu Utang pada Siswa Kelas XI Akuntansi

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    Penelitian ini bertujuan untuk mengetahui seberapa besar Pengaruh Keaktifan Siswa terhadap Prestasi Belajar Mata Pelajaran Akuntansi Mengelola Kartu Utang pada Siswa Kelas XI Akuntansi SMK Negeri 1 Makassar. Penelitian ini merupakan jenis penelitian kuantitatif. Populasinya adalah seluruh siswa kelas XI Akuntansi SMK Negeri 1 Makassar tahun ajaran 2014/2015 yang berjumlah 139 orang, dan sampelnya berjumlah 80 orang. Teknik pengumpulan data yang digunakan adalah kuesioner dan dokumentasi.Teknik analisis data dilakukan dengan menggunakan analisis keabsahan data dan analisis statistik data dengan menggunakan program SPSS 20 for windows. Hasil persamaan regresi linear sederhana yang diperoleh antara keaktifan Siswa dan prestasi belajar yaitu = 50,918 + 0,390X. Koefisien bernilai positif artinya terjadi hubungan positif antara keaktifan siswa dengan prestasi belajar. Berdasarkan koefisien korelasi diperoleh nilai r=0,600. Nilai tersebut menunjukkan hubungan dalam kategori kuat. Sedangkan koefisien determinasi (r2) = 0,360atau36% yang berarti bahwa kontribusi keaktifan siswa terhadap prestasi belajar sebesar 36%, sedangkan sisanya sebesar 64% ditentukan oleh faktor lain diluar faktor yang diteliti dalam penelitian ini.Dari hasil perhitungan uji-t di peroleh nilai t-hitung= 6,624 lebih besar dari pada t- tabel=1,668. Hal ini berarti hipotesis yang bunyinya “keaktifan siswa berpengaruh positif dan signifikan terhadap prestasi belajar mata pelajaran akuntansi mengelola kartu utang pada siswa kelas XI Akuntansi SMK Negeri 1 Makassar” diterima. Dari hasil yang telah diperoleh maka dapat disimpulkan bahwa keaktifan siswa berpengaruh positif dan signifikan terhadap prestasi belajar mata pelajaran akuntansi mengelola kartu utang pada siswa kelas XI Akuntansi SMK Negeri 1 Makassar. Kata kunci : Keaktifan Siswa, Prestasi Belajar Akuntansi Mengelola Kartu Utan

    A randomized, placebo-controlled trial of late Na current inhibition (ranolazine) in coronary microvascular dysfunction (CMD): impact on angina and myocardial perfusion reserve.

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    AimsThe mechanistic basis of the symptoms and signs of myocardial ischaemia in patients without obstructive coronary artery disease (CAD) and evidence of coronary microvascular dysfunction (CMD) is unclear. The aim of this study was to mechanistically test short-term late sodium current inhibition (ranolazine) in such subjects on angina, myocardial perfusion reserve index, and diastolic filling.Materials and resultsRandomized, double-blind, placebo-controlled, crossover, mechanistic trial in subjects with evidence of CMD [invasive coronary reactivity testing or non-invasive cardiac magnetic resonance imaging myocardial perfusion reserve index (MPRI)]. Short-term oral ranolazine 500-1000 mg twice daily for 2 weeks vs. placebo. Angina measured by Seattle Angina Questionnaire (SAQ) and SAQ-7 (co-primaries), diary angina (secondary), stress MPRI, diastolic filling, quality of life (QoL). Of 128 (96% women) subjects, no treatment differences in the outcomes were observed. Peak heart rate was lower during pharmacological stress during ranolazine (-3.55 b.p.m., P < 0.001). The change in SAQ-7 directly correlated with the change in MPRI (correlation 0.25, P = 0.005). The change in MPRI predicted the change in SAQ QoL, adjusted for body mass index (BMI), prior myocardial infarction, and site (P = 0.0032). Low coronary flow reserve (CFR <2.5) subjects improved MPRI (P < 0.0137), SAQ angina frequency (P = 0.027), and SAQ-7 (P = 0.041).ConclusionsIn this mechanistic trial among symptomatic subjects, no obstructive CAD, short-term late sodium current inhibition was not generally effective for SAQ angina. Angina and myocardial perfusion reserve changes were related, supporting the notion that strategies to improve ischaemia should be tested in these subjects.Trial registrationclinicaltrials.gov Identifier: NCT01342029
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