451 research outputs found
Heat Transfer in the Environment: Development and Use of Fiber-Optic Distributed Temperature Sensing
To tell or not to tell: Preference elicitation with and without emphasis on scientific uncertainty
Decisions about the optimal use of coastal and marine resources must be taken under high uncertainty about environmental impacts and may conflict with public perception of the risk associated with current blue growth initiatives. In a discrete choice experiment conducted in valuation workshops in five communities in Arctic Norway, we examine public preferences for various aquaculture expansion paths. Respondents prefer a smaller expansion in terms of the number of aquaculture sites compared to the planned expansion. Emphasizing scientific uncertainty regarding the negative environmental impacts of aquaculture leads to lower resistance against the planned expansion
An Extended Network of Genomic Maintenance in the Archaeon Pyrococcus abyssi Highlights Unexpected Associations between Eucaryotic Homologs.
In Archaea, the proteins involved in the genetic information processing pathways, including DNA replication, transcription, and translation, share strong similarities with those of eukaryotes. Characterizations of components of the eukaryotic-type replication machinery complex provided many interesting insights into DNA replication in both domains. In contrast, DNA repair processes of hyperthermophilic archaea are less well understood and very little is known about the intertwining between DNA synthesis, repair and recombination pathways. The development of genetic system in hyperthermophilic archaea is still at a modest stage hampering the use of complementary approaches of reverse genetics and biochemistry to elucidate the function of new candidate DNA repair gene. To gain insights into genomic maintenance processes in hyperthermophilic archaea, a protein-interaction network centred on informational processes of Pyrococcus abyssi was generated by affinity purification coupled with mass spectrometry. The network consists of 132 interactions linking 87 proteins. These interactions give insights into the connections of DNA replication with recombination and repair, leading to the discovery of new archaeal components and of associations between eucaryotic homologs. Although this approach did not allow us to clearly delineate new DNA pathways, it provided numerous clues towards the function of new molecular complexes with the potential to better understand genomic maintenance processes in hyperthermophilic archaea. Among others, we found new potential partners of the replication clamp and demonstrated that the single strand DNA binding protein, Replication Protein A, enhances the transcription rate, in vitro, of RNA polymerase. This interaction map provides a valuable tool to explore new aspects of genome integrity in Archaea and also potentially in Eucaryotes
Assessment of a vertical high-resolution distributed-temperature-sensing system in a shallow thermohaline environment
Calibrating Single-Ended Fiber-Optic Raman Spectra Distributed Temperature Sensing Data
Hydrologic research is a very demanding application of fiber-optic distributed temperature sensing (DTS) in terms of precision, accuracy and calibration. The physics behind the most frequently used DTS instruments are considered as they apply to four calibration methods for single-ended DTS installations. The new methods presented are more accurate than the instrument-calibrated data, achieving accuracies on the order of tenths of a degree root mean square error (RMSE) and mean bias. Effects of localized non-uniformities that violate the assumptions of single-ended calibration data are explored and quantified. Experimental design considerations such as selection of integration times or selection of the length of the reference sections are discussed, and the impacts of these considerations on calibrated temperatures are explored in two case studies
Direct Compression Behavior of Low- and High-Methoxylated Pectins
The objective of this study was to evaluate possible usefulness of pectins for direct compression of tablets. The deformation behavior of pectin grades of different degree of methoxylation (DM), namely, 5%, 10%, 25%, 35%, 40%, 50%, and 60% were, examined in terms of yield pressures (YP) derived from Heckel profiles for both compression and decompression and measurements of elastic recovery after ejection. All pectin grades showed a high degree of elastic recovery. DM 60% exhibited most plastic deformation (YP 70.4Â MPa) whereas DM 5% (104.6Â MPa) and DM 10% (114.7Â MPa) least. However, DM 60% gave no coherent tablets, whereas tablet tensile strengths for DM 5% and DM 10% were comparable to Starch 1500Âź. Also, Heckel profiles were similar to Starch 1500Âź. For sieved fractions (180â250 and 90â125Â ÎŒm) of DM 25% and DM 40% originating from the very same batch, YPs were alike, indicating minor effects of particle size. These facts indicate that DM is important for the compaction behavior, and batch-to-batch variability should also be considered. Therefore, pectins of low degree of methoxylation may have a potential as direct compression excipients
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Calibrating Single-Ended Fiber-Optic Raman Spectra Distributed Temperature Sensing Data
Hydrologic research is a very demanding application of fiber-optic distributed temperature sensing (DTS) in terms of precision, accuracy and calibration. The physics behind the most frequently used DTS instruments are considered as they apply to four calibration methods for single-ended DTS installations. The new methods presented are more accurate than the instrument-calibrated data, achieving accuracies on the order of tenths of a degree root mean square error (RMSE) and mean bias. Effects of localized non-uniformities that violate the assumptions of single-ended calibration data are explored and quantified. Experimental design considerations such as selection of integration times or selection of the length of the reference sections are discussed, and the impacts of these considerations on calibrated temperatures are explored in two case studies.Keywords: temperature, distributed temperature sensing, hydrology, calibratio
Taxonomy and pathology of Togninia (Diaporthales) and its Phaeoacremonium anamorphs.
The genus Togninia (Diaporthales, Togniniaceae) is here monographed along with its Phaeoacremonium (Pm.) anamorphs. Ten species of Togninia and 22 species of Phaeoacremonium are treated. Several new species of Togninia (T.) are described, namely T. argentinensis (anamorph Pm. argentinense), T. austroafricana (anamorph Pm. austroafricanum), T. krajdenii, T. parasitica, T. rubrigena and T. viticola. New species of Phaeoacremonium include Pm. novae-zealandiae (teleomorph T. novae-zealandiae), Pm. iranianum, Pm. sphinctrophorum and Pm. theobromatis. Species can be identified based on their cultural and morphological characters, supported by DNA data derived from partial sequences of the actin and Ă-tubulin genes. Phylogenies of the SSU and LSU rRNA genes were used to determine whether Togninia has more affinity with the Calosphaeriales or the Diaporthales. The results confirmed that Togninia had a higher affinity to the Diaporthales than the Calosphaeriales. Examination of type specimens revealed that T. cornicola, T. vasculosa, T. rhododendri, T. minima var. timidula and T. villosa, were not members of Togninia. The new combinations Calosphaeria cornicola, Calosphaeria rhododendri, Calosphaeria transversa, Calosphaeria tumidula, Calosphaeria vasculosa and Jattaea villosa are proposed. Species of Phaeoacremonium are known vascular plant pathogens causing wilting and dieback of woody plants. The most prominent diseases in which they are involved are Petri disease and esca, which occur on grapevines and are caused by a complex of fungi, often including multiple species of Phaeoacremonium. Various Phaeoacremonium species are opportunistic fungi on humans and cause phaeohyphomycosis. The correct and rapid identification of Phaeoacremonium species is important to facilitate the understanding of their involvement in plant as well as human disease. A rapid identification method was developed for the 22 species of Phaeacremonium. It involved the use of 23 species-specific primers, including 20 primers targeting the Ă-tubulin gene and three targeting the actin gene. These primers can be used in 14 multiplex reactions. Additionally, a multiple-entry electronic key based on morphological, cultural and Ă-tubulin sequence data was developed to facilitate phenotypic and sequence-based species identification of the different Phaeoacremonium species. Separate dichotomous keys are provided for the identification of the Togninia and Phaeoacremonium species. Keys for the identification of Phaeoacremonium-like fungi and the genera related to Togninia are also provided. The mating strategy of several Togninia species was investigated with ascospores obtained from fertile perithecia produced in vitro. Togninia argentinensis and T. novae-zealandiae have homothallic mating systems, whereas T. austroafricana, T. krajdenii, T. minima, T. parasitica, T. rubrigena and T. viticola were heterothallic.
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Environmental temperature sensing using Raman spectra DTS fiber-optic methods
Raman spectra distributed temperature sensing (DTS) by fiber-optic cables has
recently shown considerable promise for the measuring and monitoring of surface and
near-surface hydrologic processes such as groundwaterâsurface water interaction,
borehole circulation, snow hydrology, soil moisture studies, and land surface energy
exchanges. DTS systems uniquely provide the opportunity to monitor water, air, and
media temperatures in a variety of systems at much higher spatial and temporal
frequencies than any previous measurement method. As these instruments were originally
designed for fire and pipeline monitoring, their extension to the typical conditions
encountered by hydrologists requires a working knowledge of the theory of operation,
limitations, and system accuracies, as well as the practical aspects of designing either
short- or long-term experiments in remote or challenging terrain. This work focuses on
providing the hydrologic user with sufficient knowledge and specifications to allow sound
decisions on the application and deployment of DTS systems.Keywords: Hydrology, Temperature, Fiber opti
Action Principle in Nonequilibrium Statistical Dynamics
We introduce a variational method for approximating distribution functions of
dynamics with a ``Liouville operator'' \hL, in terms of a {\em nonequilibrium
action functional} for two independent (left and right) trial states. The
method is valid for deterministic or stochastic Markov dynamics, and for
stationary or time-dependent distributions. A practical Rayleigh-Ritz procedure
is advanced, whose inputs are finitely-parametrized ansatz for the trial
states, leading to a ``parametric action'' for their evolution. The
Euler-Lagrange equations of the action principle are Hamiltonian in form
(generally noncanonical). This permits a simple identification of fixed points
as critical points of the parametric Hamiltonian. We also establish a
variational principle for low-order statistics, such as mean values and
correlation functions, by means of {\em least effective action.} The latter is
a functional of the given variable, which is positive and convex as a
consequence of H\"{o}lder realizability inequalities. Its value measures the
``cost'' for a fluctuation from the average to occur and in a weak-noise limit
it reduces to the Onsager-Machlup action. In general, the effective action is
shown to arise from the nonequilibrium action functional by a constrained
variation. This result provides a Rayleigh-Ritz scheme for calculating just the
desired low-order statistics, with internal consistency checks less demanding
than for the full distribution.Comment: 46 pages, LaTex Version 2.09, tar + gzip + uuencode The tar file
contains xyzvar.tex, the LaTeX file itself, and seceq.sty, a stylefile for
sequential numering of equations by section. The file seceq.sty will
automatically be input from the same directory when formatting the LaTeX
file. The paper is submitted to Phys. Rev.
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