2,358 research outputs found

    Bisimple monogenic orthodox semigroups

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    We give a complete description of the structure of all bisimple orthodox semigroups generated by two mutually inverse elements

    Lattice isomorphisms of bisimple monogenic orthodox semigroups

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    Using the classification and description of the structure of bisimple monogenic orthodox semigroups obtained in \cite{key10}, we prove that every bisimple orthodox semigroup generated by a pair of mutually inverse elements of infinite order is strongly determined by the lattice of its subsemigroups in the class of all semigroups. This theorem substantially extends an earlier result of \cite{key25} stating that the bicyclic semigroup is strongly lattice determined.Comment: Semigroup Forum (published online: 15 April 2011

    Flavor Alignment Solutions to the Strong CP Problem in Supersymmetry

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    An approach to solving the Strong CP Problem in supersymmetric theories is discussed which uses abelian family symmetries to align the mass matrices of the quarks and squarks. In this way both the Strong CP Problem and the characteristic flavor and CP problems of supersymmetry can be solved in a single way.Comment: 13 pages, LaTe

    Flipping SU(5) Towards Five Dimensional Unification

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    It is shown that embedding of flipped SU(5) in a five-dimensional SO(10) enables exact unification of the gauge coupling constants. The demand for the unification uniquely determines both the compactification scale and the cutoff scale. These are found to be 5.5 \times 10^{14} GeV and 1.0 \times 10^{17} GeV respectively. The theory explains the absence of d=5 proton-decay operators through the implementation of the missing partner mechanism. On the other hand, the presence of d=6 proton-decay operators points towards the bulk localization of the first and the second family of matter fields.Comment: 21 pages, references added, 3 Postscript figures, ReVTeX

    State-wide survey of boat-based recreational fishing in Western Australia 2013/14

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    Based on the outcomes of an international workshop on recreational fishing survey methods in 2010, the Department of Fisheries developed an integrated survey involving several methods to provide a robust and cost-effective approach for obtaining annual estimates of recreational catch by boat-based fishers at both state-wide and bioregional levels

    Climate Change in Queensland's Grazing Lands. I. Approaches and Climatic Trends

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    Climate change is an important global issue but is yet to be recognised as such by many rangelands users. This paper reviews some of the uncertainties relating to pre-instrumental and future climate change and documents current trends and fluctuations in climate of Queensland's grazing lands. Analysis of daily climate surfaces for Queensland's pastoral/cropping zone shows high variability in annual rainfall which is influenced by the El NiHo-Southern Oscillation (ENSO) phenomenon. This relationship, when examined using moving windows, has changed during this century with the 1930-40s being a period of low correlation. Minimum temperatures taken from the climate surfaces also changed, showing a significant (P<0.01) increase over time especially in May. Over the 40 years since 1957, annual minimum temperatures have increased by l.0°C for the pastoral/cropping zone and coastal sub-zone, winter minimum temperatures by 1.2°C for the pastoral/cropping zone (1.3°C for the coastal sub-zone), summer minimum temperatures by 0.7°C for the pastoral/cropping zone and coastal sub-zone, and May minimum temperatures by 2.8°C for the pastoral/cropping zone (3.0°C for the coastal sub-zone). Consistent significant trends in vapour pressure (increasing, P<0.001) and solar radiation (decreasing, P<0.05) also occurred in May. The mechanisms for the identified climate trends and unusual behaviour of ENS0 are the subject of speculation with attribution of causes to natural variability or the enhanced greenhouse effect being unresolved. Continued monitoring of these trends and fluctuations will be important for the future management of Queensland's grazing lands with this analysis highlighting the need for discrimination of trends from natural variability. In terms of grazing management and degradation processes, this work also highlights that general changes in climate averages may disguise important variation at yearly and decadal time scales

    Occurrence of methicillin-resistant Staphylococcus aureus in surface waters near industrial hog operation spray fields

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    Industrial hog operations (IHOs) have been identified as a source of antibiotic-resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). However, few studies have investigated the presence of antibiotic-resistant S. aureus in the environment near IHOs, specifically surface waters proximal to spray fields where IHO liquid lagoon waste is sprayed. Surface water samples (n = 179) were collected over the course of approximately one year from nine locations in southeastern North Carolina and analyzed for the presence of presumptive MRSA using CHROMagar MRSA media. Culture-based, biochemical, and molecular tests, as well as matrix-assisted laser desorption/ionization-time of flight mass spectrometry were used to confirm that isolates that grew on CHROMagar MRSA media were S. aureus. Confirmed S. aureus isolates were then tested for susceptibility to 16 antibiotics and screened for molecular markers of MRSA (mecA, mecC) and livestock adaptation (absence of scn). A total of 12 confirmed MRSA were detected in 9 distinct water samples. Nine of 12 MRSA isolates were also multidrug-resistant (MDRSA [i.e., resistant to ≥ 3 antibiotic classes]). All MRSA were scn-positive and most (11/12) belonged to a staphylococcal protein A (spa) type t008, which is commonly associated with humans. Additionally, 12 confirmed S. aureus that were methicillin-susceptible (MSSA) were recovered, 7 of which belonged to spa type t021 and were scn-negative (a marker of livestock-adaptation). This study demonstrated the presence of MSSA, MRSA, and MDRSA in surface waters adjacent to IHO lagoon waste spray fields in southeastern North Carolina. To our knowledge, this is the first report of waterborne S. aureus from surface waters proximal to IHOs
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