907 research outputs found

    Field Study for Remote Sensing: An instructor's manual

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    The need for and value of field work (surface truthing) in the verification of image identification from high atitude infrared and multispectral space sensor images are discussed in this handbook which presents guidelines for developing instructional and research procedures in remote sensing of the environment

    Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient

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    Critical thermal limits are thought to be correlated with the elevational distribution of species living in tropical montane regions, but with upper limits being relatively invariant compared to lower limits. To test this hypothesis, we examined the variation of thermal physiological traits in a group of terrestrial breeding frogs (Craugastoridae) distributed along a tropical elevational gradient. We measured the critical thermal maximum (CTmax; n = 22 species) and critical thermal minimum (CTmin; n = 14 species) of frogs captured between the Amazon floodplain (250 m asl) and the high Andes (3,800 m asl). After inferring a multilocus species tree, we conducted a phylogenetically informed test of whether body size, body mass, and elevation contributed to the observed variation in CTmax and CTmin along the gradient. We also tested whether CTmax and CTmin exhibit different rates of change given that critical thermal limits (and their plasticity) may have evolved differently in response to different temperature constraints along the gradient. Variation of critical thermal traits was significantly correlated with speciesâ elevational midpoint, their maximum and minimum elevations, as well as the maximum air temperature and the maximum operative temperature as measured across this gradient. Both thermal limits showed substantial variation, but CTmin exhibited relatively faster rates of change than CTmax, as observed in other taxa. Nonetheless, our findings call for caution in assuming inflexibility of upper thermal limits and underscore the value of collecting additional empirical data on speciesâ thermal physiology across elevational gradients.A widely held assumption is that climatic niches have not changed along the history of species, both within and among closely related species. Using a phylogenetic framework, this study documents high variability in both elevational distribution and tolerance to heat among closely related species. Our findings suggest that thermal traits in ectotherms can adjust rapidly and so cannot be simply extrapolated from relatives.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136724/1/ece32929_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136724/2/ece32929.pd

    Nb3AlNb_{3}Al prototype conductor for the transmission line magnet

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    The Very Large Hadron Collider (VLHC), under consideration for construction at Fermilab in the next 1-2 decades, is a 100 TeV cm pp collider. A major cost driver is the magnet. R&D is underway on several possible magnet designs. A low-field (2T) superferric magnet, sometimes called a transmission line magnet, may be the most cost- effective route to the VLHC. Although NbTi is now the cheapest superconductor measured in cost/kA-meter, Nb/sub 3/Al has the potential advantage that it remains superconducting at higher temperature. It may be particularly suited to the single "turn" and long straight lengths of the transmission line design. The combination of the simple magnet design and the higher strain tolerance than e.g. Nb/sub 3/Sn allows a simple process of cable fabrication, reaction, and magnet assembly. This higher strain tolerance is an advantage for splicing in the field. Sumitomo Electric Industries is producing an Nb/sub 3/Al conductor for the Fermilab low-field magnet program. (9 refs)

    XMM-Newton Surveys of the Canada-France Redshift Survey Fields - III: The Environments of X-ray Selected AGN at 0.4<z<0.6

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    The environmental properties of a sample of 31 hard X-ray selected AGN are investigated, from scales of 500 kpc down to 30 kpc, and are compared to a control sample of inactive galaxies. The AGN all lie in the redshift range 0.4<z<0.6. The accretion luminosity-density of the Universe peaks close to this redshift range, and the AGN in the sample have X-ray luminosities close to the knee in the hard X-ray luminosity function, making them representative of the population which dominated this important phase of energy conversion. Using both the spatial clustering amplitude and near neighbour counts it is found that the AGN have environments that are indistinguishable from normal, inactive galaxies over the same redshift range and with similar optical properties. Typically, the environments are of sub-cluster richness, in contrast to similar studies of high-z quasars, which are often found in clusters with comparable richness to the Abell R>=0 clusters. It is suggested that minor mergers with low mass companions is a likely candidate for the mechanism by which these modest luminosity AGN are fuelled.Comment: 12 pages, 6 figures, accepted by MNRA

    3D-HST+CANDELS : the evolution of the galaxy size-mass distribution since z=3

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    Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and we find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, R eff∝(1 + z)–1.48, and moderate evolution for the late-type population, R eff∝(1 + z)-0.75Peer reviewedFinal Accepted Versio

    Modulation of cognitive performance and mood by aromas of peppermint and ylang-ylang

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    This study provides further evidence for the impact of the aromas of plant essential oils on aspects of cognition and mood in healthy participants. One hundred and forty-four volunteers were randomly assigned to conditions of ylang-ylang aroma, peppermint aroma, or no aroma control. Cognitive performance was assessed using the Cognitive Drug Research computerized assessment battery, with mood scales completed before and after cognitive testing. The analysis of the data revealed significant differences between conditions on a number of the factors underpinning the tests that constitute the battery. Peppermint was found to enhance memory whereas ylang-ylang impaired it, and lengthened processing speed. In terms of subjective mood peppermint increased alertness and ylang-ylang decreased it, but significantly increased calmness. These results provide support for the contention that the aromas of essential oils can produce significant and idiosyncratic effects on both subjective and objective assessments of aspects of human behavior. They are discussed with reference to possible pharmacological and psychological modes of influence
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