4,725 research outputs found
GEOS-C radar altimeter characteristics
The purpose of the GEOS-C mission and the operating characteristics of its special K-band altimeter are outlined. Special attention was given to the possible use of height measurements and other supporting GEOS-C data to evaluate the feasibility and value of altimetry on a global basis
Transformation and fate of microphytobenthos carbon in subtropical, intertidal sediments: potential for long-term carbon retention revealed by <sup>13</sup>C-labeling
Microphytobenthos (MPB) are ubiquitous in coastal sediments, but the fate of
their production (carbon biomass) is poorly defined. The processing and fate
of MPB-derived carbon in subtropical intertidal sediments was investigated
through in situ labeling with <sup>13</sup>C-bicarbonate. Of the added <sup>13</sup>C,
100% was fixed within ~ 4 h, suggesting that MPB
productivity was limited by inorganic carbon availability. Although there
was rapid transfer of <sup>13</sup>C to bacteria (within 12 h), a relatively small
fraction of <sup>13</sup>C was transferred to heterotrophs (up to 12.5% of
total fixed <sup>13</sup>C into bacteria and 0.01% into foraminifera). MPB was
the major reservoir for <sup>13</sup>C throughout the study, suggesting that
production of extracellular polymeric substances was limited and/or MPB
recycled <sup>13</sup>C. This retention of <sup>13</sup>C was reflected in remarkably
slow estimated turnover times for the MPB community (66–100 d). Over 31 d,
~ 70% of the <sup>13</sup>C was lost from sediments. This was
primarily via resuspension (~ 55%), enhanced by elevated
freshwater flow following rainfall. A further ~ 13% was
lost via fluxes of dissolved inorganic carbon during inundation. However,
<sup>13</sup>C losses via dissolved organic carbon fluxes from inundated sediments
(0.5%) and carbon dioxide fluxes from exposed sediments (<0.1%) were minimal. The retention of ~ 30% of the carbon
fixed by MPB within one tidal exposure after > 30 d, despite high
resuspension, demonstrates the potentially substantial longer term retention
of MPB-derived carbon in unvegetated sediments and suggests that MPB may
contribute to carbon burial ("blue carbon")
Computational analysis of stochastic heterogeneity in PCR amplification efficiency revealed by single molecule barcoding
The polymerase chain reaction (PCR) is one of the most widely used techniques in molecular biology. In combination with High Throughput Sequencing (HTS), PCR is widely used to quantify transcript abundance for RNA-seq, and in the context of analysis of T and B cell receptor repertoires. In this study, we combine DNA barcoding with HTS to quantify PCR output from individual target molecules. We develop computational tools that simulate both the PCR branching process itself, and the subsequent subsampling which typically occurs during HTS sequencing. We explore the influence of different types of heterogeneity on sequencing output, and compare them to experimental results where the efficiency of amplification is measured by barcodes uniquely identifying each molecule of starting template. Our results demonstrate that the PCR process introduces substantial amplification heterogeneity, independent of primer sequence and bulk experimental conditions. This heterogeneity can be attributed both to inherited differences between different template DNA molecules, and the inherent stochasticity of the PCR process. The results demonstrate that PCR heterogeneity arises even when reaction and substrate conditions are kept as constant as possible, and therefore single molecule barcoding is essential in order to derive reproducible quantitative results from any protocol combining PCR with HTS
Signal for CP violation in decays
We analyze the partial rate asymmetry in
decays () which results from the interference of
the nonresonant decay amplitude and the resonant amplitude for followed by the decay . The CP
violating phase can be extracted from the measured asymmetry. We find
that the partial rate asymmetry for is
, while for it amounts .Comment: 3 pages, latex, no figures, Talk given by S. Fajfer at the Hyperons,
Charm and Beauty Hadrons, Genova, Italy, 30 June -3 July 1998, to appear as
proceedings in Nucl. Phys.
Music in advertising and consumer identity: The search for Heideggerian authenticity
This study discusses netnographic findings involving 472 YouTube postings categorized to identify themes regarding consumers’ experience of music in advertisements. Key themes relate to musical taste, musical indexicality, musical repetition and musical authenticity. Postings reveal how music conveys individual taste and is linked to personal memories and Heidegger’s coincidental time where moments of authenticity may be triggered in a melee of emotions, memories and projections. Identity protection is enabled as consumers frequently resist advertisers’ attempts to use musical repetition to impose normative identity. Critiques of repetition in the music produce Heideggerian anxiety leading to critically reflective resistance. Similarly, where advertising devalues the authenticity of iconic pieces of music, consumers often resist such authenticity transgressions as a threat to their own identity. The Heideggerian search for meaning in life emphasizes the significance of philosophically driven ideological authenticity in consumers’ responses to music in advertisements
Ngrams and Engrams: the use of structural and conceptual features to discriminate between English translations of religious texts
In this paper, we present experiments using the Linguistic Inquiry and Word Count (LIWC) program, a ‘closed-class keyword’ (CCK) analysis and a ‘correspondence analysis’ (CA) to examine whether the Scientology texts of L. Ron Hubbard are linguistically and conceptually like those of other religions. A Kruskal–Wallis test comparing the frequencies of LIWC category words in the Scientology texts and the English translations of the texts of five other religions showed that there were eighteen categories for which the Scientology texts differed from the others, and between one and seventeen for the other religions. In the CCK experiment, keywords typical of each religion were found, both by comparing the religious texts with one another and with the Brown corpus of general English. The most typical keywords were looked up in a concordancer and were manually coded with conceptual tags. The set of categories found for the Scientology texts showed little overlap with those found for the others. Our CA experiments produced fairly clear clusters of texts by religion. Scientology texts were seen at one pole on the first factor, with Christian and Islamic texts at the other. It appears that, in several ways, the Scientology texts are dissimilar to the texts of some of the world's major religions
Multi-wavelength Observations of Dusty Star Formation at Low and High Redshift
This paper examines what can be learned about high-redshift star formation
from the small fraction of high-redshift galaxies' luminosities that is emitted
at accessible wavelengths. We review and quantify empirical correlations
between bolometric luminosities produced by star formation and the UV, mid-IR,
sub-mm, and radio luminosities of galaxies in the local universe. These
correlations suggest that observations of high-redshift galaxies at any of
these wavelengths should constrain their star-formation rates to within
0.2--0.3 dex. We assemble the limited evidence that high-redshift galaxies obey
these locally calibrated correlations. The characteristic luminosities and dust
obscurations of galaxies at z ~ 0, z ~ 1, and z ~ 3 are reviewed. After
discussing the relationship between the high-redshift populations selected in
surveys at different wavelengths, we calculate the contribution to the 850um
background from each. The available data show that a correlation between
star-formation rate and dust obscuration L_dust/L_UV exists at low and high
redshift. This correlation plays a central role in the major conclusion of this
paper: most star formation at high redshift occurred in galaxies with 1 <
L_dust/L_UV < 100 similar to those that host the majority of star formation in
the local universe and to those that are detected in UV-selected surveys.
(abridged)Comment: Scheduled for publication in ApJ v544 Dec 2000. Significant changes
to section 4. Characteristic UV and dust luminosities of star-forming
galaxies at redshifts z~0, z~1, and z~3 presented. Existence of extremely
obscured galaxies more clearly acknowledged. Original conclusions reinforced
by the observed correlation between bolometric luminosity and dust
obscuration at 0<z<
- …
