99 research outputs found
Quantum Branching Programs and Space-Bounded Nonuniform Quantum Complexity
In this paper, the space complexity of nonuniform quantum computations is
investigated. The model chosen for this are quantum branching programs, which
provide a graphic description of sequential quantum algorithms. In the first
part of the paper, simulations between quantum branching programs and
nonuniform quantum Turing machines are presented which allow to transfer lower
and upper bound results between the two models. In the second part of the
paper, different variants of quantum OBDDs are compared with their
deterministic and randomized counterparts. In the third part, quantum branching
programs are considered where the performed unitary operation may depend on the
result of a previous measurement. For this model a simulation of randomized
OBDDs and exponential lower bounds are presented.Comment: 45 pages, 3 Postscript figures. Proofs rearranged, typos correcte
The rise and fall of the Phytophthora infestans lineage that triggered the Irish potato famine
Phytophthora infestans, the cause of potato late blight, is infamous for
having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P.
infestans diversity outside of its Mexican center of origin was low, and one
scenario held that a single strain, US-1, had dominated the global population
for 150 years; this was later challenged based on DNA analysis of historical
herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern
strains. We conclude that the nineteenth century epidemic was caused by a
unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct
from all examined modern strains, but it is a close relative of US-1, which
replaced it outside of Mexico in the twentieth century. We propose that HERB-1
and US-1 emerged from a metapopulation that was established in the early 1800s
outside of the species' center of diversity.Comment: To be published in eLIF
Gleiche Sicherheit für alle statt NATO-Vorherrschaft: Beiträge zum 17. Dresdner Friedenssymposium am 21. Februar 2009
Die Projektgruppe „Für eine Globale Friedensordnung“ stellt im Dresdener Friedenssymposium Arbeitsergebnisse vor.:Gerda Krause, Eröffnung.
Autorenbeiträge:
Peter Strutynsky, Die Globalisierung der NATO oder die Militarisierung des Globus.
Erhard Crome, Gleiche Sicherheit für alle - Alternativen zur NATO.
Manfred Sauer, NATO – nicht die Sicherheit, die wir meinen.
Horst Schneider, Gedanken zum Kolloquiumsthema Gleiche Sicherheit für alle statt NATO-Vorherrschaft.
Nachträglich eingereichter Beitrag zum 13. Dresdner Symposium Für eine globale Friedensordnung, Heft 93/2009:
Detlef Bald, Das Beispiel vom Primat der Politik – Die Kontrolle der Atomwaffen in der Bonner Republik
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
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A protocol for an intercomparison of biodiversity and ecosystem services models using harmonized land-use and climate scenarios
To support the assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the IPBES Expert Group on Scenarios and Models is carrying out an intercomparison of biodiversity and ecosystem services models using harmonized scenarios (BES-SIM). The goals of BES-SIM are (1) to project the global impacts of land-use and climate change on biodiversity and ecosystem services (i.e., nature's contributions to people) over the coming decades, compared to the 20th century, using a set of common metrics at multiple scales, and (2) to identify model uncertainties and research gaps through the comparisons of projected biodiversity and ecosystem services across models. BES-SIM uses three scenarios combining specific Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs)-SSP1xRCP2.6, SSP3xRCP6.0, SSP5xRCP8.6-to explore a wide range of land-use change and climate change futures. This paper describes the rationale for scenario selection, the process of harmonizing input data for land use, based on the second phase of the Land Use Harmonization Project (LUH2), and climate, the biodiversity and ecosystem services models used, the core simulations carried out, the harmonization of the model output metrics, and the treatment of uncertainty. The results of this collaborative modeling project will support the ongoing global assessment of IPBES, strengthen ties between IPBES and the Intergovernmental Panel on Climate Change (IPCC) scenarios and modeling processes, advise the Convention on Biological Diversity (CBD) on its development of a post-2020 strategic plans and conservation goals, and inform the development of a new generation of nature-centred scenarios
Genomic and dietary discontinuities during the Mesolithic and Neolithic in Sicily
Sicily is a key region for understanding the agricultural transition in the Mediterranean because of its central position. Here, we present genomic and stable isotopic data for 19 prehistoric Sicilians covering the Mesolithic to Bronze Age periods (10,700-4,100 yBP). We find that Early Mesolithic hunter-gatherers (HGs) from Sicily are a highly drifted lineage of the Early Holocene western European HGs, whereas Late Mesolithic HGs carry ∼20% ancestry related to northern and (south) eastern European HGs, indicating substantial gene flow. Early Neolithic farmers are genetically most similar to farmers from the Balkans and Greece, with only ∼7% of ancestry from local Mesolithic HGs. The genetic discontinuities during the Mesolithic and Early Neolithic match the changes in material culture and diet. Three outlying individuals dated to ∼8,000 yBP; however, suggest that hunter-gatherers interacted with incoming farmers at Grotta dell'Uzzo, resulting in a mixed economy and diet for a brief interlude at the Mesolithic-Neolithic transition.Funding. The Max Planck Society financed the genetic, isotopic, and radiocarbon analyses. S. Talamo has received funding from the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (grant agreement No. 803147 RESOLUTION, https://site.unibo.it/resolution-erc/en).Peer reviewe
Dairying, diseases and the evolution of lactase persistence in Europe
Update notice Author Correction: Dairying, diseases and the evolution of lactase persistence in Europe (Nature, (2022), 608, 7922, (336-345), 10.1038/s41586-022-05010-7) Nature, Volume 609, Issue 7927, Pages E9, 15 September 2022In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years(1). Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions(2,3). Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectoriesthan uniform selection since the Neolithic period. In the UK Biobank(4,5) cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.Peer reviewe
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