808 research outputs found
Thyroid hormones correlate with resting metabolic rate, not daily energy expenditure, in two charadriiform seabirds
K. Woo, M. Le Vaillant, T. van Nus, and especially A. Wesphal, J. Schultner and I. Dorresteijn, assisted with field work, often under unpleasant conditions. K. Wauthier was instrumental in wrestling the gamma counter into submission. P. Redman and C. Hambly conducted the isotopic analyses. K. Scott and K. Campbell provided the FoxBox. K.H.E. benefited from a Natural Sciences and Engineering Research Council (NSERC) Vanier Scholarship, Association of Canadian Universities for Northern Studies Garfield Weston Northern Studies Award and the Arctic Institute of North America Jennifer Robinson Scholarship. Research support came from Bird Studies Canada/Society of Canadian Ornithologists James Baillie Award, Animal Behavior Society Research Grant, American Ornithologistsâ Union Research Grant, Frank Chapman Research Grant, the Waterbird Society Nisbet Grant and NSERC Discovery Grants to J.F.H. and W.G.A. Any use of trade names is for descriptive purposes only and does not imply endorsement by the US Government.Peer reviewedPublisher PD
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Observation of playa salts as nuclei in orographic wave clouds
During the Ice in Clouds Experiment-Layer Clouds (ICE-L), dry lakebed, or playa, salts from the Great Basin region of the United States were observed as cloud nuclei in orographic wave clouds over Wyoming. Using a counterflow virtual impactor in series with a single-particle mass spectrometer, sodium-potassium-magnesium-calcium-chloride salts were identified as residues of cloud droplets. Importantly, these salts produced similar mass spectral signatures to playa salts with elevated cloud condensation nuclei (CCN) efficiencies close to sea salt. Using a suite of chemical characterization instrumentation, the playa salts were observed to be internally mixed with oxidized organics, presumably produced by cloud processing, as well as carbonate. These salt particles were enriched as residues of large droplets (>19 ÎŒm) compared to smaller droplets (>7 ÎŒm). In addition, a small fraction of silicate-containing playa salts were hypothesized to be important in the observed heterogeneous ice nucleation processes. While the high CCN activity of sea salt has been demonstrated to play an important role in cloud formation in marine environments, this study provides direct evidence of the importance of playa salts in cloud formation in continental North America has not been shown previously. Studies are needed to model and quantify the impact of playas on climate globally, particularly because of the abundance of playas and expected increases in the frequency and intensity of dust storms in the future due to climate and land use changes
The fables of pity: Rousseau, Mandeville and the animal-fable
Copyright @ 2012 Edinburgh University PressPrompted by Derridaâs work on the animal-fable in eighteenth-century debates about political power, this article examines the role played by the fiction of the animal in thinking of pity as either a natural virtue (in Rousseauâs Second Discourse) or as a natural passion (in Mandevilleâs The Fable of the Bees). The war of fables between Rousseau and Mandeville â and their hostile reception by Samuel Johnson and Adam Smith â reinforce that the animal-fable illustrates not so much the proper of man as the possibilities and limitations of a moral philosophy that is unable to address the political realities of the state
Physics-based multiscale coupling for full core nuclear reactor simulation
Numerical simulation of nuclear reactors is a key technology in the quest for improvements in efficiency, safety, and reliability of both existing and future reactor designs. Historically, simulation of an entire reactor was accomplished by linking together multiple existing codes that each simulated a subset of the relevant multiphysics phenomena. Recent advances in the MOOSE (Multiphysics Object Oriented Simulation Environment) framework have enabled a new approach: multiple domain-specific applications, all built on the same software framework, are efficiently linked to create a cohesive application. This is accomplished with a flexible coupling capability that allows for a variety of different data exchanges to occur simultaneously on high performance parallel computational hardware. Examples based on the KAIST-3A benchmark core, as well as a simplified Westinghouse AP-1000 configuration, demonstrate the power of this new framework for tacklingâin a coupled, multiscale mannerâcrucial reactor phenomena such as CRUD-induced power shift and fuel shuffle.Massachusetts Institute of Technology. Department of Nuclear Science and EngineeringIdaho National Laboratory (Contract DE-AC07-05ID14517
Windscapes shape seabird instantaneous energy costs but adult behavior buffers impact on offspring
Acknowledgements K. Ashbrook, M. Barrueto, K. Elner, A. Hargreaves, S. Jacobs, G. Lancton, M. LeVaillant, E. Grosbellet, A. Moody, A. Ronston, J. Provencher, P. Smith, K. Woo and P. Woodward helped in the field. J. Nakoolak kept us safe from bears. N. Sapir and two anonymous reviewers provided very useful comments on an earlier version of our manuscript. R. Armstrong at the Nunavut Research Institute, M. Mallory at the Canadian Wildlife Service Northern Research Division and C. Eberl at National Wildlife Research Centre in Ottawa provided logistical support. F. Crenner, N. Chatelain and M. Brucker customized the GPS at the IPHC-CNRS. KHE received financial support through a NSERC Vanier Canada Graduate Scholarship, ACUNS Garfield Weston Northern Studies scholarship and AINA Jennifer Robinson Scholarship and JFH received NSERC Discovery Grant funding. J. Welcker generously loaned some accelerometers. All procedures were approved under the guidelines of the Canadian Council for Animal Care.Peer reviewedPublisher PD
HSD3B1 genotype identifies glucocorticoid responsiveness in severe asthma
Asthma resistance to glucocorticoid treatment is a major health problem with unclear etiology. Glucocorticoids inhibit adrenal androgen production. However, androgens have potential benefits in asthma. HSD3B1 encodes for 3ÎČ-hydroxysteroid dehydrogenase-1 (3ÎČ-HSD1), which catalyzes peripheral conversion from adrenal dehydroepiandrosterone (DHEA) to potent androgens and has a germline missense-encoding polymorphism. The adrenal restrictive HSD3B1(1245A) allele limits conversion, whereas the adrenal permissive HSD3B1(1245C) allele increases DHEA metabolism to potent androgens. In the Severe Asthma Research Program (SARP) III cohort, we determined the association between DHEA-sulfate and percentage predicted forced expiratory volume in 1 s (FEV1PP). HSD3B1(1245) genotypes were assessed, and association between adrenal restrictive and adrenal permissive alleles and FEV1PP in patients with (GC) and without (noGC) daily oral glucocorticoid treatment was determined (n = 318). Validation was performed in a second cohort (SARP I&II; n = 184). DHEA-sulfate is associated with FEV1PP and is suppressed with GC treatment. GC patients homozygous for the adrenal restrictive genotype have lower FEV1PP compared with noGC patients (54.3% vs. 75.1%; P < 0.001). In patients with the homozygous adrenal permissive genotype, there was no FEV1PP difference in GC vs. noGC patients (73.4% vs. 78.9%; P = 0.39). Results were independently confirmed: FEV1PP for homozygous adrenal restrictive genotype in GC vs. noGC is 49.8 vs. 63.4 (P < 0.001), and for homozygous adrenal permissive genotype, it is 66.7 vs. 67.7 (P = 0.92). The adrenal restrictive HSD3B1(1245) genotype is associated with GC resistance. This effect appears to be driven by GC suppression of 3ÎČ-HSD1 substrate. Our results suggest opportunities for prediction of GC resistance and pharmacologic intervention
Practical Approach to Surge and Surge Control Systems
TutorialPg. 147-174This paper addresses the area of compressor stability, surge and surge control and relates to the practical aspects involved. An emphasis is placed on the physical understanding of surge phenomena and on the practical limitations of surge control systems. Topics discussed are physical interpretation of instability, causative factors, types of stall, machine and process design factors, surge effects and characteristics, control system types and practical application aspects. Some case studies also are presented. The discussion primarily relates to centrifugal compressors, but several aspects pertain to axial flow compressors as well. The paper is split into three sections: Section A consists of an introduction to surge and a discussion of centrifugal compressor design and process factors that affect operating stability. Section B discusses the various types of control schemes and surge protection devices. Several examples and common pitfalls are addressed. Section C addresses the important design tool, surge system simulation. Several references are provided to enable the reader to pursue this topic in greater detail
The Carnegie Supernova Project: First Near-Infrared Hubble Diagram to z~0.7
The Carnegie Supernova Project (CSP) is designed to measure the luminosity
distance for Type Ia supernovae (SNe Ia) as a function of redshift, and to set
observational constraints on the dark energy contribution to the total energy
content of the Universe. The CSP differs from other projects to date in its
goal of providing an I-band {rest-frame} Hubble diagram. Here we present the
first results from near-infrared (NIR) observations obtained using the Magellan
Baade telescope for SNe Ia with 0.1 < z < 0.7. We combine these results with
those from the low-redshift CSP at z <0.1 (Folatelli et al. 2009). We present
light curves and an I-band Hubble diagram for this first sample of 35 SNe Ia
and we compare these data to 21 new SNe Ia at low redshift. These data support
the conclusion that the expansion of the Universe is accelerating. When
combined with independent results from baryon acoustic oscillations (Eisenstein
et al. 2005), these data yield Omega_m = 0.27 +/- 0.0 (statistical), and
Omega_DE = 0.76 +/- 0.13 (statistical) +/- 0.09 (systematic), for the matter
and dark energy densities, respectively. If we parameterize the data in terms
of an equation of state, w, assume a flat geometry, and combine with baryon
acoustic oscillations, we find that w = -1.05 +/- 0.13 (statistical) +/- 0.09
(systematic). The largest source of systematic uncertainty on w arises from
uncertainties in the photometric calibration, signaling the importance of
securing more accurate photometric calibrations for future supernova cosmology
programs. Finally, we conclude that either the dust affecting the luminosities
of SNe Ia has a different extinction law (R_V = 1.8) than that in the Milky Way
(where R_V = 3.1), or that there is an additional intrinsic color term with
luminosity for SNe Ia independent of the decline rate.Comment: 44 pages, 23 figures, 9 tables; Accepted for publication in the
Astrophysical Journa
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