Investigation of the growth potential and ecosystem impact of intensively farmed Atlantic salmon fed on experimental diets.

There are increasing concerns regarding the environmental impacts and sustainability of intensive fish farming. In particular, criticism has centred on the use of fish meal and fish oil in the diets of farmed carnivorous fish species such as Atlantic salmon. If the industry is to continue to expand, reduction in the levels of fish meal and fish oil incorporated into diets and/or the use of alternative terrestrial sources of protein and oil must occur. The present study assesses several diet types containing different inclusion levels and /or sources of protein and oil in terms of growth and performance as well as assessing the diets in terms of sustainability and their potential to impact on the marine environment. In two nutritional studies, Atlantic salmon fed a low protein (LP) diet achieved similar growth and performance compared to fish fed a normal commercial diet (control diet) in both studies. Growth rates of fish fed a diet containing partial replacement of fishmeal with corn gluten and fish oil with rapeseed oil (SUS) were better than those of fish fed the control and LP diet and were similar to those of fish fed a high energy; nutrient dense (ND) diet. The amount of wild fish required to produce 1 Kg farmed salmon based on fish meal and fish oil inclusion levels were lowest for fish fed the SUS diet (1.3 kg) whilst fish fed LP diets had a lower conversion value compared to both the ND and control diets based on fish meal inclusion levels only. These results suggest there is potential for aquaculture to be more environmentally sustainable by reducing the amounts of marine fishmeal and oil used in diets fed to intensively farmed Atlantic salmon. In terms of dissolved wastes, fish fed a nutrient dense diet had higher feedrelated concentration peaks of ammonia detected which occurred earlier compared to fish fed other diet types. In contrast, fish introduced to low protein diets at different sizes throughout the marine phase of production had consistently lower concentration peaks of ammonia detected compared to fish fed a standard commercial ration. All groups fed a low protein diet had between 17 and 28 % less ammonia detected as a feed related concentration peak compared to the control group. The area under each concentration peak of ammonia ranged from 43.6 to 88.8 % ± 60 min of total ammonia detected over time for all diets. These results show that feeding fish diets containing lower inclusion levels of fish meal resulted in lower feed related concentration peaks of ammonia being detected. However most of the ammonia was excreted over a short time period and its potential to impact on the marine environment was assessed using mesocosm studies. In the first of two studies, mesocosms were fertilised with NH4CI based on ammonia concentration peaks from either 500 or 1000 T rainbow trout production (LN and HN enclosures respectively). These enclosures had consistently more phytoplankton present than the control enclosures. There was evidence of rapid uptake of excess nutrients with the HN enclosures having more cells present than the LN enclosures. In the second experiment, enclosures were fertilised based on ammonia concentration peaks detected from Atlantic salmon fed a low protein (LP enclosures) or a nutrient dense diet (ND enclosures). Both had consistently more cells present than the control enclosures.. These results suggest that increases in phytoplankton communities may occur as a result of a single pulsed release of ammonia simulating discharge from intensively farmed fish. The predicted rate of dissolved nitrogen production was calculated from fish introduced to low protein diets throughout a complete marine production phase using a mass balance model. Fish introduced to low protein diets at 330, 800 and 1600 g had lower dissolved N discharge rates (22.51, 22.02 and 21.07 Kg'1 NT'1 Production respectively) compared to fish fed a standard commercial ration (23.32 Kg-1 NT-1 Production). These results show that there is potential to maximise use of low protein diets, which would result in less ammonia excretion and reduce the potential risk to impact on the marine environment. In an attempt to accurately quantify waste outputs from intensively farmed Atlantic salmon a custom-made tarpaulin was designed. Initial studies have shown that there is potential to collect data on waste outputs from fish reared in the marine environment whilst taking in to account seasonal and daily fluctuations in water temperature and salinity. The system can be used to directly compare different feed types and feeding strategies. It has been shown that changing the macronutrient inclusion level and sources results in differences in the physical characteristics of extruded feeds. High energy diets and substitution diets have similar settling velocities compared to a standard commercial diet but produce lower environmental impacts when modelled for solid waste impacts. Low protein pellets have slower sinking rates but generate more waste due to a higher FCR. The data from these results should be used in conjunction with other data for a range of feeds and environmental conditions to employ a “look-up table” approach to differentiate between diets when modelling waste dispersion

Observations of X-rays and Thermal Dust Emission from the Supernova Remnant Kes 75

We present Spitzer Space Telescope and Chandra X-ray Observatory observations of the composite Galactic supernova remnant Kes 75 (G29.7-0.3). We use the detected flux at 24 microns and hot gas parameters from fitting spectra from new, deep X-ray observations to constrain models of dust emission, obtaining a dust-to-gas mass ratio M_dust/M_gas ~0.001. We find that a two-component thermal model, nominally representing shocked swept-up interstellar or circumstellar material and reverse-shocked ejecta, adequately fits the X-ray spectrum, albeit with somewhat high implied densities for both components. We surmise that this model implies a Wolf-Rayet progenitor for the remnant. We also present infrared flux upper limits for the central pulsar wind nebula.Comment: 7 pages, 2 tables, 4 figures, uses emulateapj. Accepted for publication in Ap

The Role of Diffusive Shock Acceleration on Nonequilibrium Ionization in Supernova Remnant Shocks II: Emitted Spectra

We present a grid of nonequilibrium ionization models for the X-ray spectra from supernova remnants undergoing efficient diffusive shock acceleration. The calculation follows the hydrodynamics of the blast wave as well as the time-dependent ionization of the plasma behind the shock. The ionization state is passed to a plasma emissivity code to compute the thermal X-ray emission, which is combined with the emission from nonthermal synchrotron emission to produce a self-consistent model for the thermal and nonthermal emission from cosmic-ray dominated shocks. We show how plasma diagnostics such as the G'-ratio of He-like ions, defined as the ratio of the sum of the intercombination, forbidden, and satellite lines to the resonance line, can vary with acceleration efficiency, and discuss how the thermal X-ray emission, when the time-dependent ionization is not calculated self-consistently with the hydrodynamics, can differ from the thermal X-ray emission from models which do account for the hydrodynamics. Finally we compare the thermal X-ray emission from models which show moderate acceleration (~ 35%) to the thermal X-ray emission from test-particle models.Comment: 17 pages, 12 figures. accepted for publication in the Astrophysical Journa

Nonthermal X-Rays from Supernova Remnant G330.2+1.0 and the Characteristics of its Central Compact Object

We present results from our X-ray data analysis of the SNR G330.2+1.0 and its CCO, CXOU J160103.1--513353 (J1601). Using our XMM-Newton and Chandra observations, we find that the X-ray spectrum of J1601 can be described by neutron star atmosphere models (T ~ 2.5--3.7 MK). Assuming the distance of d ~ 5 kpc for J1601 as estimated for SNR G330.2+1.0, a small emission region of R ~ 1--2 km is implied. X-ray pulsations previously suggested by Chandra are not confirmed by the XMM-Newton data, and are likely not real. However, our timing analysis of the XMM-Newton data is limited by poor photon statistics, and thus pulsations with a relatively low amplitude (i.e., an intrinsic pulsed-fraction < 40%) cannot be ruled out. Our results indicate that J1601 is a CCO similar to that in the Cassiopeia A SNR.X-ray emission from SNR G330.2+1.0 is dominated by power law continuum (Gamma ~ 2.1--2.5) which primarily originates from thin filaments along the boundary shell. This X-ray spectrum implies synchrotron radiation from shock-accelerated electrons with an exponential roll-off frequency ~ 2--3 x 10^17 Hz. For the measured widths of the X-ray filaments (D ~ 0.3 pc) and the estimated shock velocity (v_s ~ a few x 10^3 km s^-1), a downstream magnetic field B ~ 10--50 $\mu$G is derived. The estimated maximum electron energy E_max ~ 27--38 TeV suggests that G330.2+1.0 is a candidate TeV gamma-ray source. We detect faint thermal X-ray emission in G330.2+1.0. We estimate a low preshock density n_0 ~ 0.1 cm^-3, which suggests a dominant contribution from an inverse Compton mechanism (than the proton-proton collision) to the prospective gamma-ray emission. Follow-up deep radio, X-ray, and gamma-ray observations will be essential to reveal the details of the shock parameters and the nature of particle accelerations in this SNR.Comment: 26 pages, 3 tables, 7 figures (4 color figures), Accepted by Ap

Transcriptomic profiling of 39 commonly-used neuroblastoma cell lines

Neuroblastoma cell lines are an important and cost-effective model used to study oncogenic drivers of the disease. While many of these cell lines have been previously characterized with SNP, methylation, and/or mRNA expression microarrays, there has not been an effort to comprehensively sequence these cell lines. Here, we present raw whole transcriptome data generated by RNA sequencing of 39 commonly-used neuroblastoma cell lines. These data can be used to perform differential expression analysis based on a genetic aberration or phenotype in neuroblastoma (e.g., MYCN amplification status, ALK mutation status, chromosome arm 1p, 11q and/or 17q status, sensitivity to pharmacologic perturbation). Additionally, we designed this experiment to enable structural variant and/or long-noncoding RNA analysis across these cell lines. Finally, as more DNase/ATAC and histone/transcription factor ChIP sequencing is performed in these cell lines, our RNA-Seq data will be an important complement to inform transcriptional targets as well as regulatory (enhancer or repressor) elements in neuroblastoma

Intrinsic Absorption in the Spectrum of NGC 7469: Simultaneous Chandra, FUSE, and STIS Observations

We present simultaneous X-ray, far-ultraviolet, and near-ultraviolet spectra of the Seyfert 1 galaxy NGC 7469 obtained with the Chandra X-Ray Observatory, the Far Ultraviolet Spectroscopic Explorer, and the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Previous non-simultaneous observations of this galaxy found two distinct UV absorption components, at -560 and -1900 km/s, with the former as the likely counterpart of the X-ray absorber. We confirm these two absorption components in our new UV observations, in which we detect prominent O VI, Ly alpha, N V, and C IV absorption. In our Chandra spectrum we detect O VIII emission, but no significant O VIII or O VII absorption. We also detect a prominent Fe K alpha emission line in the Chandra spectrum, as well as absorption due to hydrogen-like and helium-like neon, magnesium, and silicon at velocities consistent with the -560 km/s UV absorber. The FUSE and STIS data reveal that the H I and C IV column densities in this UV- and X-ray- absorbing component have increased over time, as the UV continuum flux decreased. We use measured H I, N V, C IV, and O VI column densities to model the photoionization state of both absorbers self-consistently. We confirm the general physical picture of the outflow in which the low velocity component is a highly ionized, high density absorber with a total column density of 10^20 cm^-2, located near the broad emission line region, although due to measurable columns of N V and C IV, we assign it a somewhat smaller ionization parameter than found previously, U~1. The high velocity UV component is of lower density, log N=18.6, and likely resides farther from the central engine as we find its ionization parameter to be U=0.08.Comment: Minor correction to abstract; STScI eprint #1683; 50 pages, incl. 19 figures, 4 tables; Accepted to Ap

Cultural Heritage and the Campus Community: Academic Libraries and Museums in Collaboration

This chapter describes the broad set of collaborations that have existed for nearly a decade between the University Libraries and the Natural History Museum at the University of Colorado, Boulder. This collabo- rative partnership focuses on areas of collection management, access, user engagement, and programming as well as joint-use facility devel- opment. Continued program, accessibility, stewardship, and shared facility development will build on the sturdy foundations of shared opportunities and challenges that have defined current high levels of collaborations between these two CU-Boulder campus units.</p

Intrinsic Absorption in the Spectrum of Mrk 279: Simultaneous Chandra, FUSE, and STIS Observations

We present a study of the intrinsic X-ray and far-ultraviolet absorption in the Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from the Chandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE). We also present FUSE observations made at three additional epochs. We detect the Fe K-alpha emission line in the Chandra spectrum, and its flux is consistent with the low X-ray continuum flux level of Mrk 279 at the time of the observation. Due to low signal-to-noise ratios in the Chandra spectrum, no O VII or O VIII absorption features are observable in the Chandra data, but the UV spectra reveal strong and complex absorption from HI and high-ionization species such as O VI, N V, and C IV, as well as from low-ionization species such as C III, N III, C II, and N II in some velocity components. The far-UV spectral coverage of the FUSE data provides information on high-order Lyman series absorption, which we use to calculate the optical depths and line and continuum covering fractions in the intrinsic HI absorbing gas in a self-consistent fashion. The UV continuum flux of Mrk 279 decreases by a factor of ~7.5 over the time spanning these observations and we discuss the implications of the response of the absorption features to this change. From arguments based on the velocities, profile shapes, covering fractions and variability of the UV absorption, we conclude that some of the absorption components, particularly those showing prominent low-ionization lines, are likely associated with the host galaxy of Mrk 279, and possibly with its interaction with a close companion galaxy, while the remainder arises in a nuclear outflow.Comment: To appear in 2004 May ApJS; double-column format; 58 pages, incl. 29 figures, 9 tables; minor changes to tex

Links Between Fluctuations in Sockeye Salmon Abundance and Riparian Forest Productivity Identified by Remote Sensing

Pacific salmon (Oncorhynchus&nbsp;spp.) carcasses can fertilize riparian forests with marine-derived nutrients when populations make their annual return to natal streams to spawn; however, the strength of this cross-system linkage likely varies substantially among years due to the interannual fluctuations in abundance that characterize most salmon populations. Here, we used a 36-yr time series (1984–2019) of satellite imagery and salmon abundance estimates to assess spatiotemporal associations between forest greenness (a measure of plant productivity) and adult sockeye salmon (Oncorhynchus nerka) abundance in the lower Adams River, British Columbia, Canada. The Adams River sockeye population displays a quadrennial pattern of abundance, with a dominant cohort that spawns every four years in numbers that are typically two to three orders of magnitude larger than non-dominant cohorts. We found that variation in forest greenness was consistently explained best by models including dominant cohort year, whereas models lacking an index of salmon abundance were the lowest-ranked. Greenness of riparian vegetation increased by an average of 0.015 NDVI units (approximately 1%) in the summer after a dominant cohort return, and this effect on greenness persisted into the subsequent fall (11–13&nbsp;months after spawning). The positive association between quadrennial pulses of salmon and riparian greenness occurred in plots both within 30&nbsp;m of the stream and 95–125&nbsp;m away from the stream, indicating that the spatial extent of fertilization may occur well beyond areas directly adjacent to the riverbank. These results suggest that forests respond to cyclical variation in salmon abundance and that overwinter storage of marine-derived nutrients within catchments allows plants to capitalize on these nutrients in the following growing season. Continued advances in remote sensing technology will enhance our understanding of cross-system resource linkages and can inform the ecosystem-based management of Pacific salmon