638 research outputs found

    Performance of Seedigated and Conventionally Planted Crops

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    Seedigation is the use of a moving sprinkler irrigation system to broadcast seeds on the soil surface. Seed germination, plant characteristics and yield for grain sorghum, winter wheat and soybeans that were seedigated and conventionally planted are compared. When the seeding rates for seedigation were increased above that for conventional planting, and adequate moisture was available for germination, grain sorghum and wheat seedigated on tilled surfaces produced yields similar to conventionally planted crops. Seedigation of soybeans into fallow conditions, or when used as a relay crop, was unsuccessful. Shallow disking following seedigation did not improve germination or yield of grain sorghum or winter wheat. Using seedigation to plant wheat into soybeans offers good potential. Seedigating wheat into dense grain sorghum canopies was less successful

    Performance of Seedigated and Conventionally Planted Crops

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    Seedigation is the use of a moving sprinkler irrigation system to broadcast seeds on the soil surface. Seed germination, plant characteristics and yield for grain sorghum, winter wheat and soybeans that were seedigated and conventionally planted are compared. When the seeding rates for seedigation were increased above that for conventional planting, and adequate moisture was available for germination, grain sorghum and wheat seedigated on tilled surfaces produced yields similar to conventionally planted crops. Seedigation of soybeans into fallow conditions, or when used as a relay crop, was unsuccessful. Shallow disking following seedigation did not improve germination or yield of grain sorghum or winter wheat. Using seedigation to plant wheat into soybeans offers good potential. Seedigating wheat into dense grain sorghum canopies was less successful

    Superorganisms of the protist kingdom : a new level of biological organization

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    The concept of superorganism has a mixed reputation in biology-for some it is a convenient way of discussing supra-organismal levels of organization, and for others, little more than a poetic metaphor. Here, I show that a considerable step forward in the understanding of superorganisms results from a thorough review of the supra-organismal levels of organization now known to exist among the “unicellular” protists. Limiting the discussion to protists has enormous advantages: their bodies are very well studied and relatively simple (as compared to humans or termites, two standard examples in most discussions about superorganisms), and they exhibit an enormous diversity of anatomies and lifestyles. This allows for unprecedented resolution in describing forms of supra-organismal organization. Here, four criteria are used to differentiate loose, incidental associations of hosts with their microbiota from “actual” superorganisms: (1) obligatory character, (2) specific spatial localization of microbiota, (3) presence of attachment structures and (4) signs of co-evolution in phylogenetic analyses. Three groups-that have never before been described in the philosophical literature-merit special attention: Symbiontida (also called Postgaardea), Oxymonadida and Parabasalia. Specifically, it is argued that in certain cases-for Bihospites bacati and Calkinsia aureus (symbiontids), Streblomastix strix (an oxymonad), Joenia annectens and Mixotricha paradoxa (parabasalids) and Kentrophoros (a ciliate)-it is fully appropriate to describe the whole protist-microbiota assocation as a single organism (“superorganism”) and its elements as “tissues” or, arguably, even “organs”. To account for this level of biological complexity, I propose the term “structured superorganism”

    Observation of high-energy neutrinos from the Galactic plane

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    The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, has been a mystery for over a century. Due to deflection in interstellar magnetic fields, cosmic rays from the Milky Way arrive at Earth from random directions. However, near their sources and during propagation, cosmic rays interact with matter and produce high-energy neutrinos. We search for neutrino emission using machine learning techniques applied to ten years of data from the IceCube Neutrino Observatory. We identify neutrino emission from the Galactic plane at the 4.5σ\sigma level of significance, by comparing diffuse emission models to a background-only hypothesis. The signal is consistent with modeled diffuse emission from the Galactic plane, but could also arise from a population of unresolved point sources.Comment: Submitted on May 12th, 2022; Accepted on May 4th, 202

    Searches for Neutrinos from Gamma-Ray Bursts using the IceCube Neutrino Observatory

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    Gamma-ray bursts (GRBs) are considered as promising sources of ultra-high-energy cosmic rays (UHECRs) due to their large power output. Observing a neutrino flux from GRBs would offer evidence that GRBs are hadronic accelerators of UHECRs. Previous IceCube analyses, which primarily focused on neutrinos arriving in temporal coincidence with the prompt gamma rays, found no significant neutrino excess. The four analyses presented in this paper extend the region of interest to 14 days before and after the prompt phase, including generic extended time windows and targeted precursor searches. GRBs were selected between May 2011 and October 2018 to align with the data set of candidate muon-neutrino events observed by IceCube. No evidence of correlation between neutrino events and GRBs was found in these analyses. Limits are set to constrain the contribution of the cosmic GRB population to the diffuse astrophysical neutrino flux observed by IceCube. Prompt neutrino emission from GRBs is limited to \lesssim1% of the observed diffuse neutrino flux, and emission on timescales up to 10410^4 s is constrained to 24% of the total diffuse flux

    All-flavor constraints on nonstandard neutrino interactions and generalized matter potential with three years of IceCube DeepCore data

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    We report constraints on nonstandard neutrino interactions (NSI) from the observation of atmospheric neutrinos with IceCube, limiting all individual coupling strengths from a single dataset. Furthermore, IceCube is the first experiment to constrain flavor-violating and nonuniversal couplings simultaneously. Hypothetical NSI are generically expected to arise due to the exchange of a new heavy mediator particle. Neutrinos propagating in matter scatter off fermions in the forward direction with negligible momentum transfer. Hence the study of the matter effect on neutrinos propagating in the Earth is sensitive to NSI independently of the energy scale of new physics. We present constraints on NSI obtained with an all-flavor event sample of atmospheric neutrinos based on three years of IceCube DeepCore data. The analysis uses neutrinos arriving from all directions, with reconstructed energies between 5.6 GeV and 100 GeV. We report constraints on the individual NSI coupling strengths considered singly, allowing for complex phases in the case of flavor-violating couplings. This demonstrates that IceCube is sensitive to the full NSI flavor structure at a level competitive with limits from the global analysis of all other experiments. In addition, we investigate a generalized matter potential, whose overall scale and flavor structure are also constrained

    Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale νμ_{μ} Disappearance at IceCube

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    We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter εμτ. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of −0.0041≤εμτ≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date

    A Large-Scale Multi-ancestry Genome-wide Study Accounting for Smoking Behavior Identifies Multiple Significant Loci for Blood Pressure

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    Genome-wide association analysis advanced understanding of blood pressure (BP), a major risk factor for vascular conditions such as coronary heart disease and stroke. Accounting for smoking behavior may help identify BP loci and extend our knowledge of its genetic architecture. We performed genome-wide association meta-analyses of systolic and diastolic BP incorporating gene-smoking interactions in 610,091 individuals. Stage 1 analysis examined similar to 18.8 million SNPs and small insertion/deletion variants in 129,913 individuals from four ancestries (European, African, Asian, and Hispanic) with follow-up analysis of promising variants in 480,178 additional individuals from five ancestries. We identified 15 loci that were genome-wide significant (p <5 x 10(-8)) in stage 1 and formally replicated in stage 2. A combined stage 1 and 2 meta-analysis identified 66 additional genome-wide significant loci (13, 35, and 18 loci in European, African, and trans-ancestry, respectively). A total of 56 known BP loci were also identified by our results (p <5 x 10(-8)). Of the newly identified loci, ten showed significant interaction with smoking status, but none of them were replicated in stage 2. Several loci were identified in African ancestry, highlighting the importance of genetic studies in diverse populations. The identified loci show strong evidence for regulatory features and support shared pathophysiology with cardiometabolic and addiction traits. They also highlight a role in BP regulation for biological candidates such as modulators of vascular structure and function (CDKN1B, BCAR1-CFDP1, PXDN, EEA1), ciliopathies (SDCCAG8, RPGRIP1L), telomere maintenance (TNKS, PINX1, AKTIP), and central dopaminergic signaling MSRA, EBF2).Peer reviewe

    Search for Quantum Gravity Using Astrophysical Neutrino Flavour with IceCube

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    Along their long propagation from production to detection, neutrino states undergo quantum interference which converts their types, or flavours. High-energy astrophysical neutrinos, first observed by the IceCube Neutrino Observatory, are known to propagate unperturbed over a billion light years in vacuum. These neutrinos act as the largest quantum interferometer and are sensitive to the smallest effects in vacuum due to new physics. Quantum gravity (QG) aims to describe gravity in a quantum mechanical framework, unifying matter, forces and space-time. QG effects are expected to appear at the ultra-high-energy scale known as the Planck energy, EP1.22×1019E_{P}\equiv 1.22\times 10^{19}~giga-electronvolts (GeV). Such a high-energy universe would have existed only right after the Big Bang and it is inaccessible by human technologies. On the other hand, it is speculated that the effects of QG may exist in our low-energy vacuum, but are suppressed by the Planck energy as EP1E_{P}^{-1} (1019\sim 10^{-19}~GeV1^{-1}), EP2E_{P}^{-2} (1038\sim 10^{-38}~GeV2^{-2}), or its higher powers. The coupling of particles to these effects is too small to measure in kinematic observables, but the phase shift of neutrino waves could cause observable flavour conversions. Here, we report the first result of neutrino interferometry~\cite{Aartsen:2017ibm} using astrophysical neutrino flavours to search for new space-time structure. We did not find any evidence of anomalous flavour conversion in IceCube astrophysical neutrino flavour data. We place the most stringent limits of any known technologies, down to 104210^{-42}~GeV2^{-2}, on the dimension-six operators that parameterize the space-time defects for preferred astrophysical production scenarios. For the first time, we unambiguously reach the signal region of quantum-gravity-motivated physics.Comment: The main text is 7 pages with 3 figures and 1 table. The Appendix includes 5 pages with 3 figure

    Gene-educational attainment interactions in a multi-population genome-wide meta-analysis identify novel lipid loci

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