747 research outputs found
M+D: conceptual guidelines for compiling a materials library
This article proposes to present a study conducted by the Raw Materials research group, the results of which comprise the conceptual guidelines for compiling an M+D material library. The study includes the topic, materials and design taking the impact of the changes that came into being in the post industrial era on project methodologies and the search for information regarding materials.
Taking into account the importance and complexity that these relationships have taken on currently, we have studied the issue of materials based on Manzini (1983) and Ashby and Johnson (2002). Afterward different databases and materials libraries located in the Brazil, the United States, France and Italy geared toward design professionals and students were analyzed to understand what information and means of access to them were available. The project methodologies were approached based on Löbach (1991), Bürdeck (1994), Schulmann (1994), Baxter (1998), Dantas (1998 and 2005) and Papanek (1995 and 2000). This study sought to identify the key elements of the role of materials in the project process today, to serve as a parameter for the analysis of the models studied.
A comparative analysis of the models investigated enabled identification of positive and negative aspects to adapt to the needs previously mentioned and identify conceptual guidelines for compiling a collection of materials for use in design projects.
Keywords:
Design, Materials, Project Methodology, Library</p
Jumping behavior in singularly perturbed systems modelling bimolecular reactions
Singular singularly perturbed systems of ordinary differential equations modelling the dynamics of fast bimolecular reactions are considered. The asymptotic behavior of the solution of the initial value problem on a finite time interval is studied under conditions (change of stability) which are not treated in the usual standard theory. The application of the obtained results to the model under consideration yields conditions under which the reaction rate jumps. This behavior has to. be taken into account for identification problems in chemical process modelling
Exploiting the Temporal Logic Hierarchy and the Non-Confluence Property for Efficient LTL Synthesis
The classic approaches to synthesize a reactive system from a linear temporal
logic (LTL) specification first translate the given LTL formula to an
equivalent omega-automaton and then compute a winning strategy for the
corresponding omega-regular game. To this end, the obtained omega-automata have
to be (pseudo)-determinized where typically a variant of Safra's
determinization procedure is used. In this paper, we show that this
determinization step can be significantly improved for tool implementations by
replacing Safra's determinization by simpler determinization procedures. In
particular, we exploit (1) the temporal logic hierarchy that corresponds to the
well-known automata hierarchy consisting of safety, liveness, Buechi, and
co-Buechi automata as well as their boolean closures, (2) the non-confluence
property of omega-automata that result from certain translations of LTL
formulas, and (3) symbolic implementations of determinization procedures for
the Rabin-Scott and the Miyano-Hayashi breakpoint construction. In particular,
we present convincing experimental results that demonstrate the practical
applicability of our new synthesis procedure
Comparative Fungal Community Analyses Using Metatranscriptomics and Internal Transcribed Spacer Amplicon Sequencing from Norway Spruce
The health, growth, and fitness of boreal forest trees are impacted and improved by their associated microbiomes. Microbial gene expression and functional activity can be assayed with RNA sequencing (RNA-Seq) data from host samples. In contrast, phylogenetic marker gene amplicon sequencing data are used to assess taxonomic composition and community structure of the microbiome. Few studies have considered how much of this structural and taxonomic information is included in transcriptomic data from matched samples. Here, we described fungal communities using both host-derived RNA-Seq and fungal ITS1 DNA amplicon sequencing to compare the outcomes between the methods. We used a panel of root and needle samples from the coniferous tree species Picea abies (Norway spruce) growing in untreated (nutrient-deficient) and nutrient-enriched plots at the Flakaliden forest research site in boreal northern Sweden. We show that the relationship between samples and alpha and beta diversity indicated by the fungal transcriptome is in agreement with that generated by the ITS data, while also identifying a lack of taxonomic overlap due to limitations imposed by current database coverage. Furthermore, we demonstrate how metatranscriptomics data additionally provide biologically informative functional insights. At the community level, there were changes in starch and sucrose metabolism, biosynthesis of amino acids, and pentose and glucuronate interconversions, while processing of organic macromolecules, including aromatic and heterocyclic compounds, was enriched in transcripts assigned to the genus Cortinarius.IMPORTANCE A deeper understanding of microbial communities associated with plants is revealing their importance for plant health and productivity. RNA extracted from plant field samples represents the host and other organisms present. Typically, gene expression studies focus on the plant component or, in a limited number of studies, expression in one or more associated organisms. However, metatranscriptomic data are rarely used for taxonomic profiling, which is currently performed using amplicon approaches. We created an assembly-based, reproducible, and hardware-agnostic workflow to taxonomically and functionally annotate fungal RNA-Seq data obtained from Norway spruce roots, which we compared to matching ITS amplicon sequencing data. While we identified some limitations and caveats, we show that functional, taxonomic, and compositional insights can all be obtained from RNA-Seq data. These findings highlight the potential of metatranscriptomics to advance our understanding of interaction, response, and effect between host plants and their associated microbial communities
Gravitational wave emission from dynamical stellar interactions
We are witnessing the dawn of gravitational wave (GW) astronomy. With
currently available detectors, observations are restricted to GW frequencies in
the range between and , which covers
the signals from mergers of compact objects. The launch of the space
observatory LISA will open up a new frequency band for the detection of stellar
interactions at lower frequencies. In this work, we predict the shape and
strength of the GW signals associated with common-envelope interaction and
merger events in binary stars, and we discuss their detectability. Previous
studies estimated these characteristics based on semi-analytical models. In
contrast, we used detailed three-dimensional magnetohydrodynamic simulations to
compute the GW signals. We show that for the studied models, the dynamical
phase of common-envelope events and mergers between main-sequence stars lies
outside of the detectability band of the LISA mission. We find, however, that
the final stages of common-envelope interactions leading to mergers of the
stellar cores fall into the frequency band in which the sensitivity of LISA
peaks, making them promising candidates for detection. These detections can
constrain the enigmatic common-envelope dynamics. Furthermore, future decihertz
observatories such as DECIGO or BBO would also be able to observe this final
stage and the post-merger signal, through which we might be able to detect the
formation of Thorne-\.Zytkow objects.Comment: Accepted for publication in A&A, 12 pages, 8 figure
Circulation and Oxygen Distribution in the Tropical Atlantic Cruise No. 80, Leg 1; October 26 to November 23, 2009 Mindelo (Cape Verde) to Mindelo (Cape Verde)
METEOR cruise 80/1 was a contribution to the SFB 754 “Climate-Biogeochemistry Interactions in the Tropical Ocean”. Shipboard, glider and moored observations are used to study the temporal and spatial variability of physical and biogeochemical parameters within the oxygen minimum zone (OMZ) of the tropical North Atlantic. As part of the BMBF “Nordatlantik” project, it further focuses on the equatorial current system including the Equatorial Undercurrent (EUC) and intermediate currents below. During the cruise, hydrographic station observations were performed using a CTD/O2 rosette, including water sampling for salinity, oxygen, nutrients and other biogeochemical tracers. Underway current measurements were successfully carried out with the 75 kHz ADCP borrowed from R/V POSEIDON during the first part of the cruise, and R/V METEOR’s 38 kHz ADCP during the second part. During M80/1, an intensive mooring program was carried out with 8 mooring recoveries and 8 mooring deployments. Right at the beginning of the cruise, a multidisciplinary mooring near the Cape Verde Islands was recovered and redeployed. Within the framework of SFB 754, two moorings with CTD/O2 profilers were recovered and redeployed with other instrumentation in the center and at the southern rim of the OMZ of the tropical North Atlantic. The equatorial mooring array as part of BMBF “North Atlantic” project consists of 5 current meter moorings along 23°W between 2°S and 2°N. It is aimed at quantifying the variability of the thermocline water supply toward the equatorial cold tongue which develops east of 10°W during boreal summer. Several glider missions were
performed during the cruise. One glider was recovered that was deployed two months earlier. Another glider was deployed for two short term missions, near the equator for about 8 days and near 8°N for one day. This glider was equipped with a new microstructure probe in addition to
standard sensors, i.e. CTD/O2, chlorophyll and turbidity
The Sloan Digital Sky Survey Reverberation Mapping Project: No Evidence for Evolution in the M-sigma Relation to z~1
We present host stellar velocity dispersion measurements for a sample of 88
broad-line quasars at 0.10.6) from the Sloan Digital Sky Survey
Reverberation Mapping (SDSS-RM) project. High signal-to-noise ratio coadded
spectra (average S/N~30 per 69 km/s pixel) from SDSS-RM allowed decomposition
of the host and quasar spectra, and measurement of the host stellar velocity
dispersions and black hole (BH) masses using the single-epoch (SE) virial
method. The large sample size and dynamic range in luminosity
(L5100=10^(43.2-44.7) erg/s) lead to the first clear detection of a correlation
between SE virial BH mass and host stellar velocity dispersion far beyond the
local universe. However, the observed correlation is significantly flatter than
the local relation, suggesting that there are selection biases in high-z
luminosity-threshold quasar samples for such studies. Our uniform sample and
analysis enable an investigation of the redshift evolution of the M-sigma
relation free of caveats by comparing different samples/analyses at disjoint
redshifts. We do not observe evolution of the M-sigma relation in our sample,
up to z~1, but there is an indication that the relation flattens towards higher
redshifts. Coupled with the increasing threshold luminosity with redshift in
our sample, this again suggests certain selection biases are at work, and
simple simulations demonstrate that a constant M-sigma relation is favored to
z~1. Our results highlight the scientific potential of deep coadded
spectroscopy from quasar monitoring programs, and offer a new path to probe the
co-evolution of BHs and galaxies at earlier times.Comment: replaced with the accepted version (minor changes and updated
references); ApJ in press; changed title to highlight the main resul
Clumping and X-Rays in cooler B supergiant stars
B supergiants (BSGs) are evolved stars with effective temperatures between 10
to 30 kK and are important to understand massive star evolution. Located on the
edge of the line-driven wind regime, the study of their atmospheres is helpful
to understand phenomena such as the bi-stability jump. Key UV features of their
spectra have so far not been reproduced by models for types later than B1.
Here, we aim to remedy this situation via spectral analysis that accounts for
wind clumping and X-rays. In addition, we investigate the evolutionary status
of our sample stars based on the obtained stellar parameters. We determined
parameters via quantitative spectroscopy using CMFGEN and PoWR codes. The
models were compared to UV and optical data of four BSGs: HD206165, HD198478,
HD53138, and HD164353. We also study the evolutionary status of our sample
using GENEC and MESA tracks. When including clumping and X-rays, we find good
agreements between synthetic and observed spectra for our sample stars. For the
first time, we reproduced key lines in the UV. For that, we require a
moderately clumped wind (f_infty > ~0.5). We also infer relative X-ray
luminosities of ~10^-7.5 to 10^-8 -- lower than the typical ratio of 10^-7.
Moreover, we find a possible mismatch between evolutionary and spectroscopic
masses, which could be related to the mass-discrepancy problem present in other
OB stars. Our results provide evidence that X-rays and clumping are needed to
describe the winds of cool BSGs. However, their winds seem less structured than
in earlier type stars. This aligns with observational X-rays and clumping
constraints as well as recent hydrodynamical simulations. The BSGs'
evolutionary status appears diverse: some objects are potentially post-red
supergiants or merger products. The wind parameters provide evidence for a
moderate mass-loss rate increase around the bi-stability jump. Abstract
abridgedComment: 27 pages, 22 figures, accepted for publication in A&
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Unveiling the sensory and interneuronal pathways of the neuroendocrine connectome in <i>Drosophila</i>.
Neuroendocrine systems in animals maintain organismal homeostasis and regulate stress response. Although a great deal of work has been done on the neuropeptides and hormones that are released and act on target organs in the periphery, the synaptic inputs onto these neuroendocrine outputs in the brain are less well understood. Here, we use the transmission electron microscopy reconstruction of a whole central nervous system in the Drosophila larva to elucidate the sensory pathways and the interneurons that provide synaptic input to the neurosecretory cells projecting to the endocrine organs. Predicted by network modeling, we also identify a new carbon dioxide-responsive network that acts on a specific set of neurosecretory cells and that includes those expressing corazonin (Crz) and diuretic hormone 44 (Dh44) neuropeptides. Our analysis reveals a neuronal network architecture for combinatorial action based on sensory and interneuronal pathways that converge onto distinct combinations of neuroendocrine outputs
Unveiling the sensory and interneuronal pathways of the neuroendocrine connectome in Drosophila.
Neuroendocrine systems in animals maintain organismal homeostasis and regulate stress response. Although a great deal of work has been done on the neuropeptides and hormones that are released and act on target organs in the periphery, the synaptic inputs onto these neuroendocrine outputs in the brain are less well understood. Here, we use the transmission electron microscopy reconstruction of a whole central nervous system in the Drosophila larva to elucidate the sensory pathways and the interneurons that provide synaptic input to the neurosecretory cells projecting to the endocrine organs. Predicted by network modeling, we also identify a new carbon dioxide-responsive network that acts on a specific set of neurosecretory cells and that includes those expressing corazonin (Crz) and diuretic hormone 44 (Dh44) neuropeptides. Our analysis reveals a neuronal network architecture for combinatorial action based on sensory and interneuronal pathways that converge onto distinct combinations of neuroendocrine outputs
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