2,292 research outputs found
Aerosol single scattering albedo dependence on biomass combustion efficiency: Laboratory and field studies
Single scattering albedo (ω) of fresh biomass burning (BB) aerosols produced from 92 controlled laboratory combustion experiments of 20 different woods and grasses was analyzed to determine the factors that control the variability in ω. Results show that ω varies strongly with fire-integrated modified combustion efficiency (MCEFI)—higher MCEFI results in lower ω values and greater spectral dependence of ω. A parameterization of ω as a function of MCEFI for fresh BB aerosols is derived from the laboratory data and is evaluated by field observations from two wildfires. The parameterization suggests that MCEFI explains 60% of the variability in ω, while the 40% unexplained variability could be accounted for by other parameters such as fuel type. Our parameterization provides a promising framework that requires further validation and is amenable for refinements to predict ω with greater confidence, which is critical for estimating the radiative forcing of BB aerosols
Investigations of the Andean Past: Papers from the First Annual Northeast Conference on Andean Archaeology and Ethnohistory
The papers included in this volume represent fourteen of the twenty-three original papers presented at the First Annual Northeast Conference on Andean Archaeology and Ethnohistory held at Cornell University on November 13th and 14th, 1982. The papers are: The Preceramic Occupations of the Casma Valley, Peru by Michael A. Malpass, The Historical Development of a Coastal Andean Social Formation in Central Peru, 6000 to 500 B.C. by Thomas C. Patterson, Stone Tools in Ceramic Contexts: Exploring the Unstructured by Joan M. Gero, Possible Uses, Roles, and Meanings of Chavin-style Painted Textiles of South Coast Peru by Rebecca R. Stone, Megalithic Sites in the Nepena Valley, Peru by Richard E. Daggett, Huaca del Loro Revisited: The Nasca-Huarpa Connection by Allison C. Paulsen, Spatial Patterning and the Function of a Huari Architectural Compound by Christine C. Brewster-Wray, The Development of Huari Administrative Architecture by Lynda E. Spickard, Aspects of State Ideology in Huari and Tiwanaku Iconography: The Central Deity and the Sacrificer by Anita G. Cook, Shared Ideology and Parallel Political Development: Huari and Tiwanaku by William H. Isbell, Casma Incised Pottery: An Analysis of Collections from the Nepena Valley by Cheryl Daggett, High Altitude Land Use in the Huamachuco Area by T. McGreevy and R. Shaughnessy, La Lengua Pescadora: the Lost Dialect of Chimu Fishermen by Joel Rabinowitz, and The Chancas of Angaraes: 1450(?)--1765 by Paul H. Dillon.https://digitalcommons.library.umaine.edu/andean_past_special/1002/thumbnail.jp
The efficacy of whole human genome capture on ancient dental calculus and dentin
Objectives: Dental calculus is among the richest known sources of ancient DNA in the archaeological record. Although most DNA within calculus is microbial, it has been shown to contain sufficient human DNA for the targeted retrieval of whole mitochondrial genomes. Here, we explore whether calculus is also a viable substrate for whole human genome recovery using targeted enrichment techniques. Materials and methods: Total DNA extracted from 24 paired archaeological human dentin and calculus samples was subjected to whole human genome enrichment using in-solution hybridization capture and high-throughput sequencing. Results: Total DNA from calculus exceeded that of dentin in all cases, and although the proportion of human DNA was generally lower in calculus, the absolute human DNA content of calculus and dentin was not significantly different. Whole genome enrichment resulted in up to fourfold enrichment of the human endogenous DNA content for both dentin and dental calculus libraries, albeit with some loss in complexity. Recovering more on-target reads for the same sequencing effort generally improved the quality of downstream analyses, such as sex and ancestry estimation. For nonhuman DNA, comparison of phylum-level microbial community structure revealed few differences between precapture and postcapture libraries, indicating that off-target sequences in human genome-enriched calculus libraries may still be useful for oral microbiome reconstruction. Discussion: While ancient human dental calculus does contain endogenous human DNA sequences, their relative proportion is low when compared with other skeletal tissues. Whole genome enrichment can help increase the proportion of recovered human reads, but in this instance enrichment efficiency was relatively low when compared with other forms of capture. We conclude that further optimization is necessary before the method can be routinely applied to archaeological samples
Low energy atmospheric muon neutrinos in MACRO
We present the measurement of two event samples induced by atmospheric
of average energy . In the first sample,
the neutrino interacts inside the MACRO detector producing an upward-going muon
leaving the apparatus. The ratio of the number of observed to expected events
is with an angular
distribution similar to that expected from the Bartol atmospheric neutrino
flux. The second is a mixed sample of internally produced downward-going muons
and externally produced upward-going muons stopping inside the detector. These
two subsamples are selected by topological criteria; the lack of timing
information makes it impossible to distinguish stopping from downgoing muons.
The ratio of the number of observed to expected events is . Using the ratio of the two subsamples (for
which most theoretical uncertainties cancel) we can test the pathlength
dependence of the oscillation hypothesis. The probability of agreement with the
no-oscillation hypothesis is 5% .
The deviations of our observations from the expectations has a preferred
interpretation in terms of oscillations with maximal mixing and
. These parameters are in agreement
with our results from upward throughgoing muons, induced by of much
higher energies.Comment: 7 pages, 6 figures. Submitted to Phys. Lett.
Fatigue behaviour of SiC p -reinforced aluminium composites in the very high cycle regime using ultrasonic fatigue
The fatigue behaviour of a 2009/SiC/15p-T4 DRA composite has been examined in the very high cycle fatigue (VHCF) regime where 10 7 ≤ N f ≤ 10 9 cycles. Ultrasonic fatigue was used to achieve the very high cycle counts. Careful processing yielded a composite with a very homogeneous particle distribution with minimal clustering. Fatigue crack initiation was observed almost exclusively at AlCuFe inclusions with no crack initiation observed at SiC particle clusters. Fatigue lives at a given stress level exhibited minimal scatter and subsurface crack initiation was observed in all cases. This behaviour is consistent with the presence of a low number density of critical inclusions that are responsible for crack initiation very early in fatigue life.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73177/1/j.1460-2695.2006.00998.x.pd
Evidence for oscillation of atmospheric neutrinos
We present an analysis of atmospheric neutrino data from a 33.0 kiloton-year
(535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith
angle dependent deficit of muon neutrinos which is inconsistent with
expectations based on calculations of the atmospheric neutrino flux.
Experimental biases and uncertainties in the prediction of neutrino fluxes and
cross sections are unable to explain our observation. The data are consistent,
however, with two-flavor nu_mu nu_tau oscillations with sin^2(2theta)>0.82
and 5x10^-4 < delta m^2 < 6x10^-3 eV^2 at 90% confidence level.Comment: 9 pages (two-column) with 4 figures. Small corrections to Eqn.4 and
Fig.3. Final version to appear in PR
Measurement of the flux and zenith-angle distribution of upward through-going muons by Super-Kamiokande
A total of 614 upward through-going muons of minimum energy 1.6 GeV are
observed by Super-Kamiokande during 537 detector live days. The measured muon
flux is 1.74+/-0.07(stat.)+/-0.02(sys.)x10^{-13}cm^{-2}s^{-1}sr^{-1} compared
to an expected flux of 1.97+/-0.44(theo.)x10^{-13}cm^{-2}s^{-1}sr^{-1}. The
absolute measured flux is in agreement with the prediction within the errors.
However, the zenith angle dependence of the observed upward through-going muon
flux does not agree with no-oscillation predictions. The observed distortion in
shape is consistent with the \nu_\mu \nu_\tau oscillation hypothesis with
\sin^22\theta > 0.4 and 1x10^{-3} < \Delta m^2 < 1x10^{-1} eV^{2} at 90%
confidence level.Comment: 8 pages w/ 3 figures new version contains minor fixes, as it appears
in PR
Study of DJ meson decays to D+π−, D0π+ and D∗+π− final states in pp collisions
A study of D+π−, D0π+ and D∗+π− final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D1(2420)0 resonance is observed in the D∗+π− final state and the D∗2(2460) resonance is observed in the D+π−, D0π+ and D∗+π− final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the D∗+π−, D+π− and D0π+ final states
Study of B0(s)→K0Sh+h′− decays with first observation of B0s→K0SK±π∓ and B0s→K0Sπ+π−
A search for charmless three-body decays of B 0 and B0s mesons with a K0S meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the B0(s)→K0Sh+h′− decay modes (h (′) = π, K), relative to the well measured B0→K0Sπ+π− decay, are obtained. First observation of the decay modes B0s→K0SK±π∓ and B0s→K0Sπ+π− and confirmation of the decay B0→K0SK±π∓ are reported. The following relative branching fraction measurements or limits are obtained B(B0→K0SK±π∓)B(B0→K0Sπ+π−)=0.128±0.017(stat.)±0.009(syst.), B(B0→K0SK+K−)B(B0→K0Sπ+π−)=0.385±0.031(stat.)±0.023(syst.), B(B0s→K0Sπ+π−)B(B0→K0Sπ+π−)=0.29±0.06(stat.)±0.03(syst.)±0.02(fs/fd), B(B0s→K0SK±π∓)B(B0→K0Sπ+π−)=1.48±0.12(stat.)±0.08(syst.)±0.12(fs/fd)B(B0s→K0SK+K−)B(B0→K0Sπ+π−)∈[0.004;0.068]at90%CL
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