548 research outputs found

    Influence of structural position on fracture networks in the Torridon Group, Achnashellach fold and thrust belt, NW Scotland

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    Acknowledgements This research is funded by a NERC CASE studentship (NERC code NE/I018166/1) in partnership with Midland Valley. The authors thank Midland Valley for use of FieldMove Clino software for fracture data collection, and Move software for cross section construction, and strain modelling. 3D Field software is acknowledged for contour map creation. We also thank Toru Takeshita for overseeing the editorial process, and Catherine Hanks and Ole Petter Wennberg for constructive reviews.Peer reviewedPublisher PD

    Translocation of Humpback Chub into Tributary Streams of the Colorado River: Implications for Conservation of Large- River Fishes

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    The Humpback Chub Gila cypha, a large-bodied, endangered cyprinid endemic to the Colorado River basin, is in decline throughout most of its range due largely to anthropogenic factors. Translocation of Humpback Chub into tributaries of the Colorado River is one conservation activity that may contribute to the expansion of the species’ current range and eventually provide population redundancy. We evaluated growth, survival, and dispersal following translocation of approximately 900 Humpback Chub over a period of 3 years (2009, 2010, and 2011) into Shinumo Creek, a tributary stream of the Colorado River within Grand Canyon National Park. Growth and condition of Humpback Chub in Shinumo Creek were consistent among year-classes and equaled or surpassed growth estimates from both the main-stem Colorado River and the Little Colorado River, where the largest (and most stable) Humpback Chub aggregation remains. Based on passive integrated tag recoveries, 53% ( D 483/902) of translocated Humpback Chub dispersed from Shinumo Creek into the main-stem Colorado River as of January 2013, 35% leaving within 25 d following translocation. Annual apparent survival estimates within Shinumo Creek ranged from 0.22 to 0.41, but were strongly influenced by emigration. Results indicate that Shinumo Creek provides favorable conditions for growth and survival of translocated Humpback Chub and could support a new population if reproduction and recruitment occur in the future. Adaptation of translocation strategies of Humpback Chub into tributary streams ultimately may refine the role translocation plays in recovery of the species

    Food Insecurity in Bloomington-Normal: How a Grocery Cooperative Might Help Meet the Needs of Low-Income Residents

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    The purpose of this report is to understand the current food needs of marginalized community-members in the Bloomington-Normal area, to learn how Green Top Grocery may help improve food security among these residents, and to ascertain viable mechanisms to encourage involvement in the cooperative among a diversity of local residents. The findings are based on data from three focus groups and nine key-informant interviews conducted in the Bloomington-Normal community. Key findings most relevant to Green Top’s goal of encouraging a diverse membership include the following: Green Top may wish to use existing networks to build trust in the Bloomington-Normal community, keeping in mind they will need communicate in multiple languages; Green Top could educate the public about what a grocery cooperative is; Green Top could consider the needs of marginalized community members when making infrastructure decisions such was where to locate their store. A number of other findings are discussed. In conclusion, additional research is highly recommended for Green Top to move forward with their goals

    Mid-IR heterogeneous silicon photonics

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    In this paper we discuss silicon-based photonic integrated circuit technology for applications beyond the telecommunication wavelength range. Silicon-on-insulator and germanium-on-silicon passive waveguide circuits are described, as well as the integration of III-V semiconductors, IV-VI colloidal nanoparticle films and GeSn alloys on these circuits for increasing the functionality. The strong nonlinearity of silicon combined with the low nonlinear absorption in the mid-infrared is exploited to generate picosecond pulse based supercontinuum sources and optical parametric oscillators that can be used as spectroscopic sensor sources

    Toxic effects of orally ingested oil from the Deepwater Horizon spill on laughing gulls

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    The explosion of the Deepwater Horizon oil rig released millions of gallons of oil into the environment, subsequently exposing wildlife, including numerous bird species. To determine the effects of MC252 oil to species relevant to the Gulf of Mexico, studies were done examining multiple exposure scenarios and doses. In this study, laughing gulls (Leucophaeus atricilla, LAGU) were offered fish injected with MC252 oil at target doses of 5 or 10 mL/kg bw per day. Dosing continued for 27 days. Of the adult, mixed-sex LAGUs used in the present study, 10 of 20 oil exposed LAGUs survived to the end of the study; a total of 10 of the oil exposed LAGUs died or were euthanized within 20 days of initiation of the study. Endpoints associated with oxidative stress, hepatic total glutathione (tGSH), oxidized glutathione (GSSG) and reduced glutathione (rGSH) significantly increased as mean dose of oil increased, while the rGSH:GSSG ratio showed a non-significant negative trend with oil dose. A significant increase in 3-methyl histidine was found in oil exposed birds when compared to controls indicative of muscle wastage and may have been associated with the gross observation of diminished structural integrity in cardiac tissue. Consistent with previous oil dosing studies in birds, significant changes in liver, spleen, and kidney weight when normalized to body weight were observed. These studies indicate that mortality in response to oil dosing is relatively common and the mortality exhibited by the gulls is consistent with previous studies examining oil toxicity. Whether survival effects in the gull study were associated with weight loss, physiologic effects of oil toxicity, or a behavioral response that led the birds to reject the dosed fish is unknown

    Changes in white cell estimates and plasma chemistry measurements following oral or external dosing of double-crested cormorants, \u3ci\u3ePhalacocorax auritus\u3c/i\u3e, with artificially weathered MC252 oil

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    Scoping studies were designed whereby double-crested cormorants (Phalacocorax auritus) were dosed with artificially weathered Deepwater Horizon (DWH) oil either daily through oil injected feeder fish, or by application of oil directly to feathers every three days. Preening results in oil ingestion, and may be an effective means of orally dosing birds with toxicant to improve our understanding of the full range of physiological effects of oral oil ingestion on birds. Blood samples collected every 5–6 days were analyzed for a number of clinical endpoints including white blood cell (WBC) estimates and differential cell counts. Plasma biochemical evaluations were performed for changes associated with oil toxicity. Oral dosing and application of oil to feathers resulted in clinical signs and statistically significant changes in a number of biochemical endpoints consistent with petroleum exposure. In orally dosed birds there were statistically significant decreases in aspartate amino transferase (AST) and gamma glutamyl transferase (GGT) activities, calcium, chloride, cholesterol, glucose, and total protein concentrations, and increases in plasma urea, uric acid, and phosphorus concentrations. Plasma electrophoresis endpoints (pre-albumin, albumin, alpha-2 globulin, beta globulin, and gamma globulin concentrations and albumin: globulin ratios) were decreased in orally dosed birds. Birds with external oil had increases in urea, creatinine, uric acid, creatine kinase (CK), glutamate dehydrogenase (GLDH), phosphorus, calcium, chloride, potassium, albumin, alpha-1 globulin and alpha-2 globulin. Decreases were observed in AST, beta globulin and glucose. WBC also differed between treatments; however, this was in part driven by monocytosis present in the externally oiled birds prior to oil treatment

    Changes in white cell estimates and plasma chemistry measurements following oral or external dosing of double-crested cormorants, \u3ci\u3ePhalacocorax auritus\u3c/i\u3e, with artificially weathered MC252 oil

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    Scoping studies were designed whereby double-crested cormorants (Phalacocorax auritus) were dosed with artificially weathered Deepwater Horizon (DWH) oil either daily through oil injected feeder fish, or by application of oil directly to feathers every three days. Preening results in oil ingestion, and may be an effective means of orally dosing birds with toxicant to improve our understanding of the full range of physiological effects of oral oil ingestion on birds. Blood samples collected every 5–6 days were analyzed for a number of clinical endpoints including white blood cell (WBC) estimates and differential cell counts. Plasma biochemical evaluations were performed for changes associated with oil toxicity. Oral dosing and application of oil to feathers resulted in clinical signs and statistically significant changes in a number of biochemical endpoints consistent with petroleum exposure. In orally dosed birds there were statistically significant decreases in aspartate amino transferase (AST) and gamma glutamyl transferase (GGT) activities, calcium, chloride, cholesterol, glucose, and total protein concentrations, and increases in plasma urea, uric acid, and phosphorus concentrations. Plasma electrophoresis endpoints (pre-albumin, albumin, alpha-2 globulin, beta globulin, and gamma globulin concentrations and albumin: globulin ratios) were decreased in orally dosed birds. Birds with external oil had increases in urea, creatinine, uric acid, creatine kinase (CK), glutamate dehydrogenase (GLDH), phosphorus, calcium, chloride, potassium, albumin, alpha-1 globulin and alpha-2 globulin. Decreases were observed in AST, beta globulin and glucose. WBC also differed between treatments; however, this was in part driven by monocytosis present in the externally oiled birds prior to oil treatment

    Effects of crystallographic anisotropy on fracture development and acoustic emission in quartz

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    Transgranular microcracking is fundamental for the initiation and propagation of all fractures in rocks. The geometry of these microcracks is primarily controlled by the interaction of the imposed stress field with the mineral elastic properties. However, the effects of anisotropic elastic properties of minerals on brittle fracture are not well understood. This study examines the effects of elastic anisotropy of quartz on the geometry of brittle fracture and related acoustic emissions (AE) developed during indentation experiments on single crystals at ambient pressure and temperature. A Hertzian cone crack developed during blunt indentation of a single crystal of flawless Brazilian quartz parallel to the c axis shows geometric deviation away from predictions based on the isotropic case, consistent with trigonal symmetry. The visible cone crack penetration depth varies from 3 to 5 mm and apical angle from 53 to 40. Electron backscatter diffraction (EBSD) mapping of the crack tip shows that fracturing initiates along a ~40 ÎŒm wide process zone, comprising damage along overlapping en echelon high-index crystallographic planes, shown by discrete bands of reduced electron backscatter pattern (EBSP) quality (band contrast).Coalescence of these surfaces results in a stepped fracture morphology. Monitoring of AE during indentation reveals that the elastic anisotropy of quartz has a significant effect on AE location and focal mechanisms. Ninety-four AE events were recorded during indentation and show an increasing frequency with increasing load. They correspond to the development of subsidiary concentric cracks peripheral to the main cone crack. The strong and complex anisotropy in seismic velocity (~28% Vp, ~43% Vs with trigonal symmetry) resulted in inaccurate and high uncertainty in AE locations using Geiger location routine with an isotropic velocity model. This problem was overcome by using a relative (master event) location algorithm that only requires a priori knowledge of the velocity structure within the source volume. The AE location results correlate reasonably well to the extent of the observed cone crack. Decomposition of AE source mechanisms of the Geiger relocated events shows dominantly end-member behavior between tensile and compressive vector dipole events, with some double-couple-dominated events and no purely tensile or compressive events. The same events located by the master event algorithm yield greater percentage of vector dipole components and no double-couple events, indicating that AE source mechanism solutions can depend on AE location accuracy, and therefore, relocation routine that is utilized. Calculations show that the crystallographic anisotropy of quartz causes apparent deviation of the moment tensors away from double-couple and pure tensile/compressive sources consistent with the observations. Preliminary modeling of calcite anisotropy shows a response distinct from quartz, indicating that the effects of anisotropy on interpreting AE are complex and require detailed further study

    Testing of an oral dosing technique for double-crested cormorants, \u3ci\u3ePhalacocorax auritus\u3c/i\u3e, laughing gulls, \u3ci\u3eLeucophaeus atricilla\u3c/i\u3e, homing pigeons, \u3ci\u3eColumba livia\u3c/i\u3e, and western sandpipers, \u3ci\u3eCalidris mauri\u3c/i\u3e, with artificially weather MC252 oil

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    Scoping studies were designed to determine if double-crested cormorants (Phalacocorax auritus), laughing gulls (Leucophaues atricilla), homing pigeons (Columba livia) and western sandpipers (Calidris mauri) that were gavaged with a mixture of artificially weathered MC252 oil and food for either a single day or 4–5 consecutive days showed signs of oil toxicity. Where volume allowed, samples were collected for hematology, plasma protein electrophoresis, clinical chemistry and electrolytes, oxidative stress and organ weigh changes. Double-crested cormorants, laughing gulls and western sandpipers all excreted oil within 30 min of dose, while pigeons regurgitated within less than one hour of dosing. There were species differences in the effectiveness of the dosing technique, with double-crested cormorants having the greatest number of responsive endpoints at the completion of the trial. Statistically significant changes in packed cell volume, white cell counts, alkaline phosphatase, alanine aminotransferase, creatine phosphokinase, gamma glutamyl transferase, uric acid, chloride, sodium, potassium, calcium, total glutathione, glutathione disulfide, reduced glutathione, spleen and liver weights were measured in double-crested cormorants. Homing pigeons had statistically significant changes in creatine phosphokinase, total glutathione, glutathione disulfide, reduced glutathione and Trolox equivalents. Laughing gulls exhibited statistically significant decreases in spleen and kidney weight, and no changes were observed in any measurement endpoints tested in western sandpipers
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