1,781 research outputs found
Resource-sensitive global production networks: reconfigured geographies of timber and acoustic guitar manufacturing
This article examines how resource materiality, scarcity, and evolving international environmental regulation shape global production networks (GPNs). Nature-facing elements, including resource scarcity and environmental regulation, have seldom featured in GPN analysis. So, too, GPN analysis emphasizes spatial relations between network actors over temporal change. We extend GPN theorization through a temporal analysis of industrial change, connecting manufacturing to upstream resource materialities and shifting regulation, and to downstream consumers increasingly concerned with provenance and material stewardship. To illustrate, we document a resource-sensitive GPN-acoustic guitar manufacturing-where scarcity of select raw materials (tonewoods) with material qualities of resonance, strength, and beauty, as well as tighter regulation, has spawned shifting economic geographies of new actors who influence the whole GPN. Such actors include specialist extraction firms, salvagers, traders, verification consultants, and customs agents who innovate in procurement and raw material supply risk management. Traditional large guitar manufacturing firms have struggled with regulation and securing consistent resource supply, although smaller lead manufacturing firms have creatively responded via novel procurement methods and marketing, developing closely bound, iterative relationships with specialist timber harvesters, traders, and with emotionally attached consumers. A cohort of tonewood supply firms and guitar manufacturers-especially in Australia, the Pacific Northwest and Canada, key locations of both resource and design expertise-have together altered material stewardship practices and commodity production. Niche strategies derive exchange value from rarity and resource innovation, embracing raw material variability, inconsistent supply, and the need for alternatives. How firms adapt to resource supply security risks, we argue, is an imperative question for GPN analysis
Keck Planet Finder: preliminary design
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. The instrument recently passed its preliminary design review and is currently in the detailed design phase. KPF is designed to characterize exoplanets using Doppler spectroscopy with a single measurement precision of 0.5 m s^(â1) or better; however, its resolution and stability will enable a wide variety of other astrophysical pursuits. KPF will have a 200 mm collimated beam diameter and a resolving power greater than 80,000. The design includes a green channel (445 nm to 600 nm) and red channel (600 nm to 870 nm). A novel design aspect of KPF is the use of a Zerodur optical bench, and Zerodur optics with integral mounts, to provide stability against thermal expansion and contraction effects
Mapping same-sex couple family households in Australia
The map (1:1,218,987) accompanying this report is the first to depict the distribution of same-sex couple family households across Australia. The map and the report contribute to emerging scholarship combining critical geographies of sexualities with quantitative techniques and GIS in order to advance the political claims of sexual minorities. The data were collected through the 2006 Census and obtained via consultation with the Australian Bureau of Statistics. These data included the number of same-sex couple family households for all Statistical Divisions across Australia and for Statistical Sub-Divisions within metropolitan capital cities. Geographical concentrations of same-sex couple family households were determined by calculating the proportion of couple family households that were same-sex in each Statistical Division and Statistical Sub-Division, since the Census defines same-sex couples as a subset of couple family households. To visualise where the proportions fell above and below the national average, and thus where concentrations were found, these ratios were converted to location quotients using the Australian average as the denominator. The map combines different scales â Statistical Divisions and Statistical Sub-Divisions â to illustrate distributional patterns between inner-city and suburban areas, as well as between urban and regional localities, across Australia. While high concentrations are found in inner-cities, there are also significant suburban and regional concentrations, thus contesting assumptions about same-sex couplesâ inner-city residential choices. Moreover, since same-sex couples were found in most Statistical Divisions, those areas below the national average cannot be considered devoid of these families, with implications for the effective operationalisation of equal rights legislation
Heterocyst placement strategies to maximize growth of cyanobacterial filaments
Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria
develop a regular pattern of heterocyst cells that fix nitrogen for the
remaining vegetative cells. We examine three different heterocyst placement
strategies by quantitatively modelling filament growth while varying both
external fixed-nitrogen and leakage from the filament. We find that there is an
optimum heterocyst frequency which maximizes the growth rate of the filament;
the optimum frequency decreases as the external fixed-nitrogen concentration
increases but increases as the leakage increases. In the presence of leakage,
filaments implementing a local heterocyst placement strategy grow significantly
faster than filaments implementing random heterocyst placement strategies. With
no extracellular fixed-nitrogen, consistent with recent experimental studies of
Anabaena sp. PCC 7120, the modelled heterocyst spacing distribution using our
local heterocyst placement strategy is qualitatively similar to experimentally
observed patterns. As external fixed-nitrogen is increased, the spacing
distribution for our local placement strategy retains the same shape while the
average spacing between heterocysts continuously increases.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Physical Biology. IOP Publishing Ltd is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from it. The definitive publisher-authenticated version
will be available onlin
Mapping same-sex couple family households in Australia
The map (1:1,218,987) accompanying this report is the first to depict the distribution of same-sex couple family households across Australia. The map and the report contribute to emerging scholarship combining critical geographies of sexualities with quantitative techniques and GIS in order to advance the political claims of sexual minorities. The data were collected through the 2006 Census and obtained via consultation with the Australian Bureau of Statistics. These data included the number of same-sex couple family households for all Statistical Divisions across Australia and for Statistical Sub-Divisions within metropolitan capital cities. Geographical concentrations of same-sex couple family households were determined by calculating the proportion of couple family households that were same-sex in each Statistical Division and Statistical Sub-Division, since the Census defines same-sex couples as a subset of couple family households. To visualise where the proportions fell above and below the national average, and thus where concentrations were found, these ratios were converted to location quotients using the Australian average as the denominator. The map combines different scales â Statistical Divisions and Statistical Sub-Divisions â to illustrate distributional patterns between inner-city and suburban areas, as well as between urban and regional localities, across Australia. While high concentrations are found in inner-cities, there are also significant suburban and regional concentrations, thus contesting assumptions about same-sex couplesâ inner-city residential choices. Moreover, since same-sex couples were found in most Statistical Divisions, those areas below the national average cannot be considered devoid of these families, with implications for the effective operationalisation of equal rights legislation
Nonnative \u3ci\u3ePhragmites australis\u3c/i\u3e Invasion into Utah Wetlands
Phragmites australis (Cav.) Trin. ex Steud. (common reed), already one of the worldâs most widespread plant species, has realized rapid range expansion in coastal wetlands of North America in the past century, but little is known about P. australis range expansion in inland wetland systems. We used genetic analyses, aerial photographs, field surveys, and a greenhouse experiment to study the extent and mechanism of nonnative P. australis invasion of Utah wetlands. We collected and genetically analyzed 39 herbarium samples across the state and 225 present-day samples from northern Utahâs major wetland complexes. All samples collected before 1993 and all samples collected outside the major wetlands of northern Utah, including some as recent as 2001, were identified as native (haplotypes A, B, D, and H). Only 10 (4%) of the present-day samples were native, each from small, discrete, low-density stands; the remaining samples were nonnative (haplotype M). Our earliest nonnative sample was collected near the Great Salt Lake in 1993. Around the Great Salt Lake, which contains 40% of Utahâs wetlands, P. australis cover has increased from 20% to 56% over the past 27 yearsâan increase that appears attributable to the nonnative strain. In a 3-month-long greenhouse experiment, the nonnative haplotype grew taller, had more aboveground biomass, and had a greater above- to belowground biomass ratio than the native haplotypes regardless of nitrogen, phosphorus, or water availability. Nonnative P. australis is rapidly invading the wetlands of northern Utah. Areas in Utah where the native P. australis remains should be identified and protected
Adaptive response of neonatal sepsis-derived Group B Streptococcus to bilirubin
This work was funded by the Neonatal Unit Endowment Fund, Aberdeen Maternity Hospital. RH is funded by a career researcher fellowship from NHS Research Scotland. SG was funded by the MRC Flagship PhD programme. We are grateful for the support of Dr Phil Cash and Aberdeen Proteomics, at University of Aberdeen, in completing this project. Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-24811-3.Peer reviewedPublisher PD
Keck Planet Finder: Zerodur optical bench mechanical design
The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. To measure Doppler shifts to 0.5 m/s or better requires some of the optics be stable to 2 nm vertically and 2 nrad in pitch angle throughout a potentially one hour long observation. One traditional approach to this thermal stability problem is to build a metal bench and then control the spectrometer thermal environment to milli-Kelvin levels. An alternative approach used by KPF is to employ a Zerodur bench of extremely low coefficient of expansion (CTE), which relaxes the thermal stability required for the spectrometer assembly. Furthermore, Zerodur optics with integral mounts are used where possible, and are placed in contact with the bench through Zerodur shims. Springs are used to preload the optics and shims within pockets machined into the Zerodur bench. We will describe how this approach has been adapted for each optic (some of which are 450 mm high with a mass of 30 kg), and how the system meets our earthquake survival requirement of 0.92 g. This mounting scheme allows us to avoid using high-CTE metals or adhesives within the optic mounting system, and therefore fully exploit the high thermal stability of the Zerodur optical bench
The formation of atomic oxygen and hydrogen in atmospheric pressure plasmas containing humidity : picosecond two-photon absorption laser induced fluorescence and numerical simulations
Atmospheric pressure plasmas are effective sources for reactive species, making them applicable for industrial and biomedical applications. We quantify ground-state densities of key species, atomic oxygen (O) and hydrogen (H), produced from admixtures of water vapour (up to 0.5%) to the helium feed gas in a radio-frequency-driven plasma at atmospheric pressure. Absolute density measurements, using two-photon absorption laser induced fluorescence, require accurate effective excited state lifetimes. For atmospheric pressure plasmas, picosecond resolution is needed due to the rapid collisional de-excitation of excited states. These absolute O and H density measurements, at the nozzle of the plasma jet, are used to benchmark a plug-flow, 0D chemical kinetics model, for varying humidity content, to further investigate the main formation pathways of O and H. It is found that impurities can play a crucial role for the production of O at small molecular admixtures. Hence, for controllable reactive species production, purposely admixed molecules to the feed gas is recommended, as opposed to relying on ambient molecules. The controlled humidity content was also identified as an effective tailoring mechanism for the O/H ratio
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