83 research outputs found
Addressing structural uncertainty of groundwater model predictions with ensemble of automatically generated models from AEM geophysical data and borehole data
Proizvodne varijable koje utječu na svojstva peleta u peletiranju taljenjem sa smjesom voskova u sferonizatoru za laboratorijsku proizvodnju
The purpose of the study was to evaluate the suitability of laboratory scale spheronizer for the production of spherical pellets loaded with diltiazem hydrochloride by wax combination. The 1:1 combination of cetyl alcohol and hydrogenated castor oil, as low and high melting point waxes, were used. The various production variables affecting the different characteristics of pellets and the process efficiency were evaluated. Drug loaded pellets were evaluated for drug release in distilled water. Bowl temperature primarily affects the sphericity and adhesion of pellets to the bowl. Mass temperature has a pronounced effect on size, size distribution and sphericity of pellets. Wax concentration affects all characteristics of pellets but adhesion was least affected. The effect of these three variables can be compensated by optimizing the friction plate speed. It has been found that the highest yield of pellets (8501400 m) with maximum sphericity can be produced by using 45 C bowl temperature, 52 C mass temperature and 1400 rpm friction plate speed.Cilj rada bio je pripraviti sferične pelete u laboratorijskom sferonizatoru koristeći smjesu voskova. Cetilni alkohol kao vosak niskog tališta i hidrogenirano ricinusovo ulje kao vosak visokog tališta, upotrebljeni su u omjeru 1:1. Proučavan je utjecaj proizvodnih varijabli na svojstva peleta i efikasnost proizvodnje te brzinu oslobađanja ljekovite tvari iz peleta u destiliranoj vodi. Na sferičnost i adhezivnost peleta najviše utječe temperatura peletiranja. Temperatura mase ima i značajan utjecaj na veličinu, raspodjelu veličine peleta i sferičnost. Koncentracija voska utječe na sva svojstva peleta, ali najmanje na adhezivnost. Učinak tih triju varijabli može se kompenzirati optimiziranjem brzine ploče za trenje. Pronađeno je da najveće iskorištenje peleta (8501400 microm) s najboljom sferičnošću ako je temperatura peletiranja 45 oC, temperatura mase 52 oC, a brzina ploče za trenje 1400 rpm
Global transition path search for dislocation formation in Ge on Si(001)
Global optimization of transition paths in complex atomic scale systems is
addressed in the context of misfit dislocation formation in a strained Ge film
on Si(001). Such paths contain multiple intermediate minima connected by
minimum energy paths on the energy surface emerging from the atomic
interactions in the system. The challenge is to find which intermediate states
to include and to construct a path going through these intermediates in such a
way that the overall activation energy for the transition is minimal. In the
numerical approach presented here, intermediate minima are constructed by
heredity transformations of known minimum energy structures and by identifying
local minima in minimum energy paths calculated using a modified version of the
nudged elastic band method. Several mechanisms for the formation of a 90{\deg}
misfit dislocation at the Ge-Si interface are identified when this method is
used to construct transition paths connecting a homogeneously strained Ge film
and a film containing a misfit dislocation. One of these mechanisms which has
not been reported in the literature is detailed. The activation energy for this
path is calculated to be 26% smaller than the activation energy for half loop
formation of a full, isolated 60{\deg} dislocation. An extension of the common
neighbor analysis method involving characterization of the geometrical
arrangement of second nearest neighbors is used to identify and visualize the
dislocations and stacking faults
Contributions to uncertainty related to hydrostratigraphic modeling using multiple-point statistics
Forecasting the flow of groundwater requires a
hydrostratigraphic model, which describes the architecture of the subsurface.
State-of-the-art multiple-point statistical (MPS) tools are readily available
for creating models depicting subsurface geology. We present a study of the
impact of key parameters related to stochastic MPS simulation of a real-world
hydrogeophysical dataset from Kasted, Denmark, using the snesim algorithm.
The goal is to study how changes to the underlying datasets propagate into
the hydrostratigraphic realizations when using MPS for stochastic modeling.
This study focuses on the sensitivity of the MPS realizations to the
geophysical soft data, borehole lithology logs, and the training image (TI).
The modeling approach used in this paper utilizes a cognitive geological
model as a TI to simulate ensemble hydrostratigraphic models. The target
model contains three overall hydrostratigraphic categories, and the MPS
realizations are compared visually as well as quantitatively using
mathematical measures of similarity. The quantitative similarity analysis is
carried out exhaustively, and realizations are compared with each other as
well as with the cognitive geological model.The results underline the importance of geophysical data for constraining
MPS simulations. Relying only on borehole data and the conceptual geology,
or TI, results in a significant increase in realization uncertainty. The
airborne transient electromagnetic SkyTEM data used in this study cover a
large portion of the Kasted model area and are essential to the
hydrostratigraphic architecture. On the other hand, the borehole lithology
logs are sparser, and 410 boreholes were present in this study. The borehole
lithology logs infer local changes in the immediate vicinity of the
boreholes, thus, in areas with a high degree of geological heterogeneity,
boreholes only provide limited large-scale structural information.
Lithological information is, however, important for the interpretation of
the geophysical responses. The importance of the TI was also studied. An
example was presented where an alternative geological model from a
neighboring area was used to simulate hydrostratigraphic models. It was
shown that as long as the geological settings are similar in nature, the
realizations, although different, still reflect the hydrostratigraphic
architecture. If a TI containing a biased geological conceptualization is
used, the resulting realizations will resemble the TI and contain less
structure in particular areas, where the soft data show almost even
probability to two or all three of the hydrostratigraphic units.</p
The taming of an impossible child: a standardized all-in approach to the phylogeny of Hymenoptera using public database sequences
<p>Abstract</p> <p>Background</p> <p>Enormous molecular sequence data have been accumulated over the past several years and are still exponentially growing with the use of faster and cheaper sequencing techniques. There is high and widespread interest in using these data for phylogenetic analyses. However, the amount of data that one can retrieve from public sequence repositories is virtually impossible to tame without dedicated software that automates processes. Here we present a novel bioinformatics pipeline for downloading, formatting, filtering and analyzing public sequence data deposited in GenBank. It combines some well-established programs with numerous newly developed software tools (available at <url>http://software.zfmk.de/</url>).</p> <p>Results</p> <p>We used the bioinformatics pipeline to investigate the phylogeny of the megadiverse insect order Hymenoptera (sawflies, bees, wasps and ants) by retrieving and processing more than 120,000 sequences and by selecting subsets under the criteria of compositional homogeneity and defined levels of density and overlap. Tree reconstruction was done with a partitioned maximum likelihood analysis from a supermatrix with more than 80,000 sites and more than 1,100 species. In the inferred tree, consistent with previous studies, "Symphyta" is paraphyletic. Within Apocrita, our analysis suggests a topology of Stephanoidea + (Ichneumonoidea + (Proctotrupomorpha + (Evanioidea + Aculeata))). Despite the huge amount of data, we identified several persistent problems in the Hymenoptera tree. Data coverage is still extremely low, and additional data have to be collected to reliably infer the phylogeny of Hymenoptera.</p> <p>Conclusions</p> <p>While we applied our bioinformatics pipeline to Hymenoptera, we designed the approach to be as general as possible. With this pipeline, it is possible to produce phylogenetic trees for any taxonomic group and to monitor new data and tree robustness in a taxon of interest. It therefore has great potential to meet the challenges of the phylogenomic era and to deepen our understanding of the tree of life.</p
Nature's Swiss Army Knives: Ovipositor Structure Mirrors Ecology in a Multitrophic Fig Wasp Community
Resource partitioning is facilitated by adaptations along niche dimensions that range from morphology to behaviour. The exploitation of hidden resources may require specially adapted morphological or sensory tools for resource location and utilisation. Differences in tool diversity and complexity can determine not only how many species can utilize these hidden resources but also how they do so.The sclerotisation, gross morphology and ultrastructure of the ovipositors of a seven-member community of parasitic wasps comprising of gallers and parasitoids developing within the globular syconia (closed inflorescences) of Ficus racemosa (Moraceae) was investigated. These wasps also differ in their parasitism mode (external versus internal oviposition) and their timing of oviposition into the expanding syconium during its development. The number and diversity of sensilla, as well as ovipositor teeth, increased from internally ovipositing to externally ovipositing species and from gallers to parasitoids. The extent of sclerotisation of the ovipositor tip matched the force required to penetrate the syconium at the time of oviposition of each species. The internally ovipositing pollinator had only one type of sensillum and a single notch on the ovipositor tip. Externally ovipositing species had multiple sensilla types and teeth on their ovipositors. Chemosensilla were most concentrated at ovipositor tips while mechanoreceptors were more widely distributed, facilitating the precise location of hidden hosts in these wasps which lack larval host-seeking behaviour. Ovipositor traits of one parasitoid differed from those of its syntopic galler congeners and clustered with those of parasitoids within a different wasp subfamily. Thus ovipositor tools can show lability based on adaptive necessity, and are not constrained by phylogeny.Ovipositor structure mirrored the increasingly complex trophic ecology and requirements for host accessibility in this parasite community. Ovipositor structure could be a useful surrogate for predicting the biology of parasites in other communities
A hymenopterists' guide to the hymenoptera anatomy ontology: utility, clarification, and future directions
Hymenoptera exhibit an incredible diversity of phenotypes, the result of ~240 million years of evolution and the primary subject of more than 250 years of research. Here we describe the history, development, and utility of the Hymenoptera Anatomy Ontology (HAO) and its associated applications. These resourc¬es are designed to facilitate accessible and extensible research on hymenopteran phenotypes. Outreach with the hymenopterist community is of utmost importance to the HAO project, and this paper is a direct response to questions that arose from project workshops. In a concerted attempt to surmount barriers of understanding, especially regarding the format, utility, and development of the HAO, we discuss the roles of homology, “preferred terms”, and “structural equivalency”. We also outline the use of Universal Resource Identifiers (URIs) and posit that they are a key element necessary for increasing the objectivity and repeatability of science that references hymenopteran anatomy. Pragmatically, we detail a mechanism (the “URI table”) by which authors can use URIs to link their published text to the HAO, and we describe an associated tool (the “Analyzer”) to derive these tables. These tools, and others, are available through the HAO Portal website (http://portal.hymao.org). We conclude by discussing the future of the HAO with respect to digital publication, cross-taxon ontology alignment, the advent of semantic phenotypes, and community-based curation.Katja C. Seltmann... Andrew D. Austin... John T. Jennings... et al
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