388 research outputs found

    Spring-neap variation in fecal pellet properties within surficial sediment of the York River stuary, Virginia

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    Fecal pellet abundance was measured within the upper seabed of the York River Estuary as part of a larger study investigating relationships between fine sediment aggregates and bed erodibility. Sedimentalogical surveys were conducted twice a month during the spring and summer of 2011 to coincide with spring or neap tidal cycles. Particle size distributions were determined by sieving the sediment using three methods: 1) typical grain size analysis, 2) gentle agitation with seawater, 3) gentle agitation with deionized water. Each method used four sieves (150, 90, 63 and 45 microns) to constrain the size abundance of the particles. The study found that resilient fecal pellets comprised up to ~30% of the total sediment within the top centimeter of the seabed, and abundance was not directly related to spring-neap tidal cycles. There was a tendency, however, for larger pellets to persist around neap tide, perhaps because stronger currents at spring tide were more likely to break apart the largest pellets. Also, a greater mass of pellets was preserved when seawater rather than deionized water was used during sieving

    Institutional leadership—the historical case study of a religious organisation

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    In this chapter, I discuss institutional leadership vis-à-vis the value of poverty. To do so, I analyse how poverty has been conceptualised within a Catholic religious organisation, the Jesuits. The chapter shows that, in the Jesuit case, poverty is not strictly defined. Instead, poverty results from the constant dialogue between the individual Jesuit and their leader. This means that the understanding of what constitutes poverty is neither explicit nor implicit. The chapter contributes to our understanding of institutional leadership as the promotion and protection of values, as per Selznick’s classical definition. However, we discuss a less known part of Selznick’s work in which the ambiguous character of values is highlighted. In this sense, and after the Jesuit case, we advance the possibility that the promotion and protection of institutional values by institutional leaders does not necessarily imply the definition of what a value is. As values are not defined beforehand but the result of a constant dialogue between the leader and their followers, institutional leadership can be revisited and freed from the heroic view that has long characterised it

    Observation of compositional domains within individual copper indium sulfide quantum dots

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    The origin of photoluminescence in copper indium sulfide (CIS) quantum dots (Qdots) has previously been ascribed to a donor-acceptor pair (DAP) recombination, with a crystal lattice defect implicated as the origin of the donor state. In this study, electron energy-loss spectroscopy (EELS) was used to observe defect-rich compositional domains within individual CIS Qdots, supporting a model of defect-state-mediated photoluminescence for these particles, and identifying them as an ideal model system for future study of lattice defects on Qdot properties
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