3,036 research outputs found

    Beavers, Castor canadensis, Feeding on Salmon Carcasses: Opportunistic Use of a Seasonally Superabundant Food Source

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    We report observations of Beavers (Castor canadensis) foraging and feeding on discarded Chinook Salmon (Oncorhynchus tshawytscha) carcasses within the confines of the Susitna River drainage in southcentral Alaska on three separate occasions between 1999 and 2004. In all three instances, Beavers were observed actively seeking out freshly discarded carcasses or transporting “fresh” salmon carcasses in their mouths. In one instance, Beavers were seen using their dextrous forefeet to “handle” chunks of salmon while hunched over carcasses and in this case we actually witnessed Beavers “chewing” and ingestion was assumed. In the other two instances, Beavers were observed swimming with salmon carcasses in their mouths. Though unique within the framework of Beaver foraging ecology, we suggest this behavior may be a fairly common strategy employed by Beavers in Alaskan streams and rivers to take advantage of a seasonally superabundant source of protein

    Supramolecular Assembly of Metal-Organic Tubes Constructed from the Ditopic Heteroscorpionate Ligand (4-NH\u3csub\u3e2\u3c/sub\u3eC\u3csub\u3e6\u3c/sub\u3eH\u3csub\u3e4\u3c/sub\u3e)CHpz\u3csub\u3e2\u3c/sub\u3e (pz = Pyrazol-1-yl) and Silver(I)

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    The possibility of constructing tubular metal-organic structures with aid of weak hydrogen-bonding interactions between suitably designed metallacycles was explored. For this purpose, the new heteroditopic ligand (4-NH2C6H4)CHpz2 (L1) was prepared in good (75 %) yield by a one-pot procedure starting from commercial 4-acetamidobenzaldehyde. The equimolar reactions between L1 and various silver(I) salts gave the intended 1:1 complexes in which the metallacycles were assembled into tubes. However, the exact nature of the assemblies (including their solvate compositions) varied depending on anion, solvent, and concentration of the original crystallization solution. For the trifluoromethanesulfonate anion, a hexameric structure was observed, whereas cyclic dimers were obtained for other anions. In the case of PF6–, an unusual, opened-cycle structure with the composition [(L1)Ag(μ-L1)Ag(CH3CN)2]2+ was also identified crystallographically. The capacity for desolvated tubular structures to be used for gas adsorption was also investigated

    Pulmonary artery stiffness in chronic obstructive pulmonary disease (copd) and emphysema: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study

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    Purpose: Chronic obstructive pulmonary disease (COPD) and particularly emphysema are characterized by stiffness of the aorta, due in part to accelerated elastin degradation in the lungs and aorta. Stiffness of the pulmonary arteries (PAs) may also be increased in COPD and emphysema, but data are lacking. We assessed PA stiffness using MRI in patients with COPD and related these measurements to COPD severity and percent emphysema. Materials and Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) COPD Study recruited 290 participants, age 50–79 years with 10 or more packyears and free of clinical cardiovascular disease. COPD severity were defined on postbronchodilator spirometry by ATS/ERS criteria. Percent emphysema was defined as the percentage of regions of the lung < -950 Hounsfield units on full-lung computed tomography (CT). PA stain was defined by the percent change in cross-sectional PA area between systole and diastole on MRI. Blood flow across the tricuspid and mitral valves was assessed by phase-contrast MRI for determination of the ventricular diastolic dysfunction (E/A ratio). Results: PA strain was reduced in COPD compared with controls (P = 0.002) and was inversely correlated with COPD severity (P = 0.004). PA strain was inversely associated to percent emphysema (P = 0.01). PA strain was also markedly correlated with right ventricular diastolic dysfunction measured by E/A ratios in the fully adjusted mix models (P = 0.02). Conclusion: PA strain is reduced in COPD, related in part to percent emphysema on CT scan, which may have implications for pulmonary small vessel flow and right ventricular function. Level of Evidence: 2 Technical Efficacy: Stage

    Energy Conversion Research

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    Contains research objectives and reports on three research projects.U. S. Air Force (Research and Technology Division) under Contract AF33(615)-1083 with the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohi

    Extracorporeal Treatment in Phenytoin Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

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    The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup conducted a systematic literature review using a standardized process to develop evidence-based recommendations on the use of extracorporeal treatment (ECTR) in patients with phenytoin poisoning. The authors reviewed all articles, extracted data, summarized findings, and proposed structured voting statements following a predetermined format. A 2-round modified Delphi method was used to reach a consensus on voting statements, and the RAND/UCLA Appropriateness Method was used to quantify disagreement. 51 articles met the inclusion criteria. Only case reports, case series, and pharmacokinetic studies were identified, yielding a very low quality of evidence. Clinical data from 31 patients and toxicokinetic grading from 46 patients were abstracted. The workgroup concluded that phenytoin is moderately dialyzable (level of evidence = C) despite its high protein binding and made the following recommendations. ECTR would be reasonable in select cases of severe phenytoin poisoning (neutral recommendation, 3D). ECTR is suggested if prolonged coma is present or expected (graded 2D) and it would be reasonable if prolonged incapacitating ataxia is present or expected (graded 3D). If ECTR is used, it should be discontinued when clinical improvement is apparent (graded 1D). The preferred ECTR modality in phenytoin poisoning is intermittent hemodialysis (graded 1D), but hemoperfusion is an acceptable alternative if hemodialysis is not available (graded 1D). In summary, phenytoin appears to be amenable to extracorporeal removal. However, because of the low incidence of irreversible tissue injury or death related to phenytoin poisoning and the relatively limited effect of ECTR on phenytoin removal, the workgroup proposed the use of ECTR only in very select patients with severe phenytoin poisoning

    Cytoreductive surgery for patients with recurrent epithelial ovarian carcinoma.

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    OBJECTIVE: This study aims to identify favorable preoperative characteristics and examine the impact of secondary cytoreductive surgery on survival for patients with recurrent epithelial ovarian carcinoma. METHODS: Patients who underwent cytoreductive surgery for recurrent epithelial ovarian cancer were identified in our surgical database for the period 1988-2004. Patient charts were reviewed and data collected regarding patient demographics, surgical management, preoperative evaluation, perioperative complications, and oncologic outcome. RESULTS: Eighty-five patients met eligibility criteria. Preoperative factors that correlated with improved survival were disease-free interval of greater than 12 months (por=1 cm (p CONCLUSION: When selecting patients for secondary cytoreduction, the most significant preoperative factors are disease-free interval and success of a prior cytoreductive effort. Once secondary cytoreductive surgery is attempted, the most important factor for improved survival is optimal cytoreduction. Of equal importance is counseling regarding the significant risk for bowel surgery, colostomy, and complications

    O/IR Polarimetry for the 2010 Decade (GAN): Science at the Edge, Sharp Tools for All

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    Science opportunities and recommendations concerning optical/infrared polarimetry for the upcoming decade in the field of Galactic science. Community-based White Paper to Astro2010 in response to the call for such papers.Comment: White Paper to the Galactic Neighborhood (GAN) Science Frontiers Panel of the Astro2010 Decadal Surve

    The laurentian record of neoproterozoic glaciation, tectonism, and eukaryotic evolution in Death Vally, California

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    Neoproterozoic strata in Death Valley, California contain eukaryotic microfossils and glacial deposits that have been used to assess the severity of putative Snowball Earth events and the biological response to extreme environmental change. These successions also contain evidence for syn-sedimentary faulting that has been related to the rifting of Rodinia, and in turn the tectonic context of the onset of Snowball Earth. These interpretations hinge on local geological relationships and both regional and global stratigraphic correlations. Here we present new geological mapping, measured stratigraphic sections, carbon and strontium isotope chemostratigraphy, and micropaleontology from the Neoproterozoic glacial deposits and bounding strata in Death Valley. These new data enable us to refine regional correlations both across Death Valley and throughout Laurentia, and construct a new age model for glaciogenic strata and microfossil assemblages. Particularly, our remapping of the Kingston Peak Formation in the Saddle Peak Hills and near the type locality shows for the first time that glacial deposits of both the Marinoan and Sturtian glaciations can be distinguished in southeastern Death Valley, and that beds containing vase-shaped microfossils are slump blocks derived from the underlying strata. These slump blocks are associated with multiple overlapping unconformities that developed during syn-sedimentary faulting, which is a common feature of Cyrogenian strata along the margin of Laurentia from California to Alaska. With these data, we conclude that all of the microfossils that have been described to date in Neoproterozoic strata of Death Valley predate the glaciations and do not bear on the severity, extent or duration of Neoproterozoic Snowball Earth events
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