12,574 research outputs found
Krill-feeding behaviour in a chinstrap penguin compared to fish-eating in Magellanic penguins: a pilot study.
Inferring feeding activities from undulations in diving depth profiles is widespread in studies of foraging marine predators. This idea, however, has rarely been tested because of practical difficulties in obtaining an independent estimate of feeding activities at a time scale corresponding to depth changes within a dive. In this study we attempted to relate depth profile undulations and feeding activities during diving in a single Chinstrap Penguin Pygoscelis antarctica, by simultaneously using a conventional time-depth recorder and a recently developed beak-angle sensor. Although failure in device attachments meant that data were obtained successfully from just a part of a single foraging trip, our preliminary results show a linear relationship between the number of depth wiggles and the number of underwater beakopening
events during a dive, suggesting that the relative feeding intensity of each dive could be represented by depth-profile data. Underwater beak-opening patterns of this krill-feeding penguin species are compared with recent data from three fish- and squid-feeding Magellanic Penguins Spheniscus magellanicus
An Analysis of Rank Ordered Data
Many methods are available to analyze rank ordered data. We used a spectral density method to analyze Formosan subterranean termite control options ranked by Louisiana homeowners. Respondents are asked to rank termite control options from the most preferred to the least preferred option. Spectral analysis results indicated that the most preferred termite control choice is a relatively cheap ($0.13 per square foot) option of liquid treatment.FST, rank ordered data, spectral analysis, Research Methods/ Statistical Methods,
Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br
Using tunable vacuum-UV radiation from a synchrotron, negative ions are detected by quadrupolar mass spectrometry following photoexcitation of three gaseous halogenated methanes CHX (X = F,Cl,Br). The anions X, H, CX, CHX and CHX are observed, and their ion yields recorded in the range 8-35 eV. The anions show a linear dependence of signal with pressure, showing that they arise from unimolecular ion-pair dissociation, generically described as AB + h A + B (+ neutrals). Absolute cross sections for ion-pair formation are obtained by calibrating the signal intensities with those of F from both SF and CF. The cross sections for formation of X + CH are much greater than for formation of CHX + H. In common with many quadrupoles, the spectra of / 1 (H) anions show contributions from all anions, and only for CHBr is it possible to perform the necessary subtraction to obtain the true H spectrum. The anion cross sections are normalised to vacuum-UV absorption cross sections to obtain quantum yields for their production. The appearance energies of X and CHX are used to calculate upper limits to 298 K bond dissociation energies for D (HC-X) and D (XHC-H) which are consistent with literature values. The spectra suggest that most of the anions are formed indirectly by crossing of Rydberg states of the parent molecule onto an ion-pair continuum. The one exception is the lowest-energy peak of F from CHF at 13.4 eV, where its width and lack of structure suggest it may correspond to a direct ion-pair transition
Characterisation of bulk water samples from copper pipes undergoing microbially influenced corrosion by diagnostic metabolomic profiling
This paper presents the application of metabolomic techniques to determine the presence of microbial influenced corrosion (MIC). In a previous study, the extracellular metabolites expressed from pipe biofilm was identified by analysing the passing water. This investigation extends this work by successfully applying a chemometric statistical analysis to the extracellular metabolomic profile of a number of water samples to identify critical metabolomic biomarkers. The chemometric analysis was able to differentiate samples due to a reduction of carboxylic acids in samples exposed to bacteria believed to cause MIC
Complete curvature homogeneous pseudo-Riemannian manifolds
We exhibit 3 families of complete curvature homogeneous pseudo-Riemannian
manifolds which are modeled on irreducible symmetric spaces and which are not
locally homogeneous. All of the manifolds have nilpotent Jacobi operators; some
of the manifolds are, in addition, Jordan Osserman and Jordan Ivanov-Petrova.Comment: Update paper to fix misprints in original versio
Multilingual assessment of early child development: Analyses from repeated observations of children in Kenya.
In many low- and middle-income countries, young children learn a mother tongue or indigenous language at home before entering the formal education system where they will need to understand and speak a countrys official language(s). Thus, assessments of children before school age, conducted in a nations official language, may not fully reflect a childs development, underscoring the importance of test translation and adaptation. To examine differences in vocabulary development by language of assessment, we adapted and validated instruments to measure developmental outcomes, including expressive and receptive vocabulary. We assessed 505 2-to-6-year-old children in rural communities in Western Kenya with comparable vocabulary tests in three languages: Luo (the local language or mother tongue), Swahili, and English (official languages) at two time points, 5-6 weeks apart, between September 2015 and October 2016. Younger children responded to the expressive vocabulary measure exclusively in Luo (44%-59% of 2-to-4-year-olds) much more frequently than did older children (20%-21% of 5-to-6-year-olds). Baseline receptive vocabulary scores in Luo (β = 0.26, SE = 0.05, p < 0.001) and Swahili (β = 0.10, SE = 0.05, p = 0.032) were strongly associated with receptive vocabulary in English at follow-up, even after controlling for English vocabulary at baseline. Parental Luo literacy at baseline (β = 0.11, SE = 0.05, p = 0.045) was associated with child English vocabulary at follow-up, while parental English literacy at baseline was not. Our findings suggest that multilingual testing is essential to understanding the developmental environment and cognitive growth of multilingual children
Investigation of the Multiple Method Adaptive Control (MMAC) method for flight control systems
The stochastic adaptive control of the NASA F-8C digital-fly-by-wire aircraft using the multiple model adaptive control (MMAC) method is presented. The selection of the performance criteria for the lateral and the longitudinal dynamics, the design of the Kalman filters for different operating conditions, the identification algorithm associated with the MMAC method, the control system design, and simulation results obtained using the real time simulator of the F-8 aircraft at the NASA Langley Research Center are discussed
DISTRIBUTION AND MOVEMENTS OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) ALONG THE NORTHERN SOUTH CAROLINA COAST: A RESEARCH PARTNERSHIP WITH ECOTOURISM
Assessments of bottlenose dolphin stocks rely on current information about the distribution and abundance of specific populations. We partnered with two ecotourism dolphin watch businesses to investigate bottlenose dolphins along the northern South Carolina coast. The temporal and spatial distribution of dolphins was examined by comparing dorsal fin images from research-based surveys with photo-identification efforts from commercial dolphin watch groups. Matches between survey locations and times revealed patterns of seasonal residency, potential migratory dispersal between seasons, and variable patterns for home range size. An enhanced understanding of the structure of local populations will contribute to the management of local fisheries, ecotour operations, and coastal ocean health
Sufficient second-order conditions for bang-bang control problems
We provide sufficient optimality conditions for optimal control problems with bang-bang controls. Building on a structural assumption on the adjoint state, we additionally need a weak second-order condition. This second-order condition is formulated with functions from an extended critical cone, and it is equivalent to a formulation posed on measures supported on the set where the adjoint state vanishes. If our sufficient optimality condition is satisfied, we obtain a local quadratic growth condition in L1(Ω)The first author was partially supported by the Spanish Ministerio de EconomÃa y Competitividad under project MTM2014-57531-P. The second author was partially supported by the DFG under grant Wa 3626/1-1
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