Cluster analysis of longline sets and fishing strategies within the Hawaii-based fishery.

Abstract In the Hawaii-based longline fishery, changes in fishing operations to target different species produce changes in the effectiveness of fishing effort units. Catch-per-unit-effort (CPUE) indices used in resource monitoring were improved by segregating dissimilar types of fishing effort. Cluster analysis was used to classify longline sets in relation to species composition of the catches. Based on proportions of eight species and three broader species groups in 46 961 longline sets from 4 years (1991)(1992)(1993)(1994) of commercial fishery data, five effort clusters were identified. Spatial distribution of sets and differences in fishing operations among clusters were then compared to reveal apparent differences in fishing strategies. Three clusters comprised N 80% of the total sets, and the catch compositions suggested targeting for either broadbill swordfish (two clusters) or bigeye tuna. The other two clusters were most similar to the tuna cluster, but their catch compositions indicated a mixed-species fishing strategy. Fishing operations were most different between sets in the tuna and swordfish clusters. Swordfish sets were characterized by (1) the largest vessels, (2) the least number of hooks per set, (3) the greatest number of lightsticks, (4) the longest set duration, (5) the highest percentage of night sets, (6) a larger percentage of sets within the full moon phase, and (7) the lowest percentage of sets within the main Hawaiian Islands Exclusive Economic Zone. Time series of CPUE for three species (bigeye tuna, yellowfin tuna, and swordfish) based on different clusters were compared, and the most appropriate CPUE time series for resource monitoring are recommended. 0 1997 Elsevier Science B.V

Spatially Resolving a Starburst Galaxy at Hard X-ray Energies: NuSTAR, Chandra, AND VLBA Observations of NGC 253

Prior to the launch of NuSTAR, it was not feasible to spatially resolve the hard (E > 10 keV) emission from galaxies beyond the Local Group. The combined NuSTAR dataset, comprised of three ~165 ks observations, allows spatial characterization of the hard X-ray emission in the galaxy NGC 253 for the first time. As a follow up to our initial study of its nuclear region, we present the first results concerning the full galaxy from simultaneous NuSTAR, Chandra, and VLBA monitoring of the local starburst galaxy NGC 253. Above ~10 keV, nearly all the emission is concentrated within 100" of the galactic center, produced almost exclusively by three nuclear sources, an off-nuclear ultraluminous X-ray source (ULX), and a pulsar candidate that we identify for the first time in these observations. We detect 21 distinct sources in energy bands up to 25 keV, mostly consisting of intermediate state black hole X-ray binaries. The global X-ray emission of the galaxy - dominated by the off-nuclear ULX and nuclear sources, which are also likely ULXs - falls steeply (photon index >~ 3) above 10 keV, consistent with other NuSTAR-observed ULXs, and no significant excess above the background is detected at E > 40 keV. We report upper limits on diffuse inverse Compton emission for a range of spatial models. For the most extended morphologies considered, these hard X-ray constraints disfavor a dominant inverse Compton component to explain the {\gamma}-ray emission detected with Fermi and H.E.S.S. If NGC 253 is typical of starburst galaxies at higher redshift, their contribution to the E > 10 keV cosmic X-ray background is < 1%.Comment: 20 pages, 14 figures, accepted for publication in Ap

European butterfly populations vary in sensitivity to weather across their geographical ranges

Aim The aim was to assess the sensitivity of butterfly population dynamics to variation in weather conditions across their geographical ranges, relative to sensitivity to density dependence, and determine whether sensitivity is greater towards latitudinal range margins. Location Europe. Time period 1980–2014. Major taxa studied Butterflies. Methods We use long-term (35 years) butterfly monitoring data from > 900 sites, ranging from Finland to Spain, grouping sites into 2° latitudinal bands. For 12 univoltine butterfly species with sufficient data from at least four bands, we construct population growth rate models that include density dependence, temperature and precipitation during distinct life-cycle periods, defined to accommodate regional variation in phenology. We use partial R2 values as indicators of butterfly population dynamics' sensitivity to weather and density dependence, and assess how these vary with latitudinal position within a species' distribution. Results Population growth rates appear uniformly sensitive to density dependence across species' geographical distributions, and sensitivity to density dependence is typically greater than sensitivity to weather. Sensitivity to weather is greatest towards range edges, with symmetry in northern and southern parts of the range. This pattern is not driven by variation in the magnitude of weather variability across the range, topographic heterogeneity, latitudinal range extent or phylogeny. Significant weather variables in population growth rate models appear evenly distributed across the life cycle and across temperature and precipitation, with substantial intraspecific variation across the geographical ranges in the associations between population dynamics and specific weather variables. Main conclusions Range-edge populations appear more sensitive to changes in weather than those nearer the centre of species' distributions, but density dependence does not exhibit this pattern. Precipitation is as important as temperature in driving butterfly population dynamics. Intraspecific variation in the form and strength of sensitivity to weather suggests that there may be important geographical variation in populations' responses to climate change

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter-estimation and model-selection algorithms were applied to the data. We report the efficiency of these search methods in detecting the numerical waveforms and measuring their parameters. We describe preliminary comparisons between the different search methods and suggest improvements for future NINJA analyses.Comment: 56 pages, 25 figures; various clarifications; accepted to CQ

The Alaska Arctic Vegetation Archive (AVA-AK)

The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation data with 25-m or better precision. Species cover data and header data are stored in a Turboveg database. A standardized Pan Arctic Species List provides a consistent nomenclature for vascular plants, bryophytes, and lichens in the archive. A web-based online Alaska Arctic Geoecological Atlas (AGA-AK) allows viewing and downloading the species data in a variety of formats, and provides access to a wide variety of ancillary data. We conducted a preliminary cluster analysis of the first 16 datasets (1,613 plots) to examine how the spectrum of derived clusters is related to the suite of datasets, habitat types, and environmental gradients. Here, we present the contents of the archive, assess its strengths and weaknesses, and provide three supplementary files that include the data dictionary, a list of habitat types, an overview of the datasets, and details of the cluster analysis

Effects of nitrogen fertilization on spotted knapweed and competing vegetation in western Montana

The effects of N fertilization on spotted knapweed (Centaurea maculosa Lamarck) and competing vegetation were studied at 2 sites in western Montana during 1981 through 1984. The N was applied 1 time at each site at rates of 56, 112, 224, and 448 kg/ha. Spotted knapweed biomass showed a significant, positive yield response to N at all rates at both sites during the year of application. The only response by spotted knapweed to N in succeeding years was in the second year at Site 1 where a significant response was detected at the 448 kg N/ha rate. Competing vegetation at Site 1 (primarily quackgrass, Agropyron repens (L.) Beauv.) in the first year showed a significant, positive response to N, while competing vegetation at Site 2 (primarily crested wheatgrass, Agropyron cristatum (L.) Gaertn.) did not respond to N in the first year. No response by competing vegetation to N in succeeding years at either site was detected. There was a significant relationship between percent knapweed and N rate at both sites in the year of N application, but not in succeeding years. These results suggest that N fertilization, by itself, as a cultural control approach to knapweed may be impractical, and could contribute toward the increase of knapweed when used in some of the plant communities normally associated with spotted knapweed on rangeland in western Montana.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202