710 research outputs found
Coherence of terrestrial vertebrate species richness with external drivers across scales and taxonomic groups
Aim: Understanding connections between environment and biodiversity is crucial for conservation, identifying causes of ecosystem stress, and predicting population responses to changing environments. Explaining biodiversity requires an under-standing of how species richness and environment covary across scales. Here, we identify scales and locations at which biodiversity is generated and correlates with environment.Location: Full latitudinal range per continent.Time Period: Present day.Major Taxa Studied: Terrestrial vertebrates: all mammals, carnivorans, bats, song-birds, hummingbirds, amphibians.Methods: We describe the use of wavelet power spectra, cross- power and coherence for identifying scale-dependent trends across Earth's surface. Spectra reveal scale- and location-dependent coherence between species richness and topography (E), mean annual precipitation (Pn), temperature (Tm) and annual temperature range (ΔT).Results: >97% of species richness of taxa studied is generated at large scales, that is, wavelengths ≳103 km, with 30%–69% generated at scales ≳104 km. At these scales, richness tends to be highly coherent and anti-correlated with E and ΔT, and positively correlated with Pn and Tm. Coherence between carnivoran richness and ΔT is low across scales, implying insensitivity to seasonal temperature variations. Conversely, amphibian richness is strongly anti-correlated with ΔT at large scales. At scales ≲103 km, examined taxa, except carnivorans, show highest richness within the trop-ics. Terrestrial plateaux exhibit high coherence between carnivorans and E at scales ∼103 km, consistent with contribution of large-scale tectonic processes to biodiver-sity. Results are similar across different continents and for global latitudinal averages. Spectral admittance permits derivation of rules-of- thumb relating long-wavelength environmental and species richness trends.Main Conclusions: Sensitivities of mammal, bird and amphibian populations to envi-ronment are highly scale dependent. At large scales, carnivoran richness is largely in-dependent of temperature and precipitation, whereas amphibian richness correlates strongly with precipitation and temperature, and anti-correlates with temperature range. These results pave the way for spectral- based calibration of models that pre-dict biodiversity response to climate change scenarios
The pro-active resource management departments of constituent entities of the tourism cluster
The proposed approach to the pro-active resource management departments of constituent entities of the tourism cluster, in particular of housekeeping service of the hotel. The developed methodology of the pro-active resource management of housekeeping service of the hotel was described
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Analysis of output surface damage resulting from single 351 nm, 3 ns pulses on sub-nanosecond laser conditioned KD2PO4 crystals
We observe that by conditioning DKDP using 500 ps laser pulses, the bulk damage threshold becomes essentially equivalent to the surface damage threshold. We report here the findings of our study of laser initiated output surface damage on 500 ps laser conditioned DKDP for test pulses at 351 nm, 3 ns. The relation between surface damage density and damaging fluence (r(f)) is presented for the first time and the morphologies of the surface sites are discussed. The results of this study suggest a surface conditioning effect resulting from exposure to 500 ps laser pulses
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Aristida jubata (Arechav.) Herter
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Laser Applications
Contains research objectives and reports on five research projects.U. S. Air Force - Office of Scientific Research(Contract F44620-71-C-0051)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300Naval Air Systems Comman
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Comparison between S/1 and R/1 tests and damage density vs. fluence (rho(phi)) results for unconditioned and sub-nanosecond laser-conditioned KD2PO4 crystals
We present S/1 and R/1 test results on unconditioned and 355 nm (3{omega}), 500 ps laser conditioned DKDP. We find up to {approx}2.5X improvement in fluence in the S/1 performance after 3{omega}, 500 ps conditioning to 5 J/cm{sup 2}. For the first time, we observe a shift to higher fluences in the R/1 results for DKDP at 3{omega}, 7 ns due to 500 ps laser conditioning. The S/1 results are compared to {rho}({phi}) results previously measured on the same DKDP crystal [1]. A consistent behavior in fluence was found between the S/1 and {rho}({phi}) results for unconditioned and 500 ps conditioned DKDP. We were successful at using Poisson statistics to derive a connection between the S/1 and {rho}({phi}) results that could be tested with our data sets by trying to predict the shape of the {rho}({phi}) curve. The value for the power dependence on fluence of {rho}({phi}) derived from the S/1 data was {approx}11 {+-} 50%. The results presented and discussed here imply a strong correlation between the damage probability (S/1) test and {rho}({phi}). We find a consistent description of the two test types in terms of a power law {rho}({phi}) and that this basic shape held for all cases, i.e. the shape was invariant between unconditioned and conditioned results
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