4,069 research outputs found
Atmospherically relevant core-shell aerosol studied using optical trapping and Mie scattering
Solid core–liquid shell aerosols have been trapped in a counter-propagating optical trap confirming potential core–shell morphology in the atmosphere.</p
Heterogeneous oxidation of nitrite anion by gas-phase ozone in an aqueous droplet levitated by laser tweezers (optical trap):is there any evidence for enhanced surface reaction?
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Development of a contextualised understanding of the diffusion of innovation among quantity surveyors in the UK construction industry
The UK construction industry is often described as slow to innovate which can be attributed to the temporary nature of construction projects and its inherently fragmented structure. The nature of innovation is a common area of research in the industry, but the diffusion of these innovations to the members of this social system is an under represented area that this research addresses. This research addresses this shortfall and focuses on providing a contextualised understanding of the key aspects of diffusion of professional practice among quantity surveyors. This is achieved by utilising a particular type of innovation, the New Rules of Measurement, as a vehicle for the analysis. A qualitative research approach that gathers the rich explanatory data is utilised, using semi structured interviews, which is lacking in the diffusion research field. This approach supports a constructivist philosophy and provides a deeper understanding of different actors’ diffusion journeys in contrast to the overwhelmingly positivist approach to previous studies of diffusion. This resulted in several original contributions to knowledge including the identification of current measurement practices within the UK construction industry, development of a contextualised understanding and diffusion of professional practice innovation model for quantity surveyors in addition to the identification of barriers to the diffusion process that are unique to the construction industry. This is important as it demonstrates areas that can be utilised and improved to assist in the diffusion of professional practice to the quantity surveying profession
On the roles of cell size and trophic strategy in North Atlantic diatom and dinoflagellate communities
We have examined the inter- and intra-group seasonal succession of 113 diatom and dinoflagellate taxa, as
surveyed by the Continuous Plankton Recorder (CPR) in the North Atlantic, by grouping taxa according to two
key functional traits: cell size (mg C cell21) and trophic strategy (photoautotrophy, mixotrophy, or heterotrophy).
Mixotrophic dinoflagellates follow photoautotrophic diatoms but precede their obligate heterotrophic
counterparts in the succession because of the relative advantages afforded by photosynthesizing when light and
nutrients are available in spring. The mean cell size of the sampled diatoms is smallest in the summer, likely
because of the higher specific nutrient affinity of smaller relative to larger cells. Contrastingly, we hypothesize that
mixotrophy diminishes the size selection based on nutrient limitation and accounts for the lack of a seasonal size
shift among surveyed dinoflagellates. Relatively small, heterotrophic dinoflagellates (mg C cell21 , 1023) peak
after other, larger dinoflagellates, in part because of the increased abundance of their small prey during nutrientdeplete
summer months. The largest surveyed diatoms (mg C cell21 . 1022) bloom later than others, and we
hypothesize that this may be because of their relatively slow maximum potential growth rates and high internal
nutrient storage, as well as to the slower predation of these larger cells. The new trait database and analysis
presented here helps translate the taxonomic information of the CPR survey into metrics that can be directly
compared with trait-based models
Contact Manifolds, Contact Instantons, and Twistor Geometry
Recently, Kallen and Zabzine computed the partition function of a twisted
supersymmetric Yang-Mills theory on the five-dimensional sphere using
localisation techniques. Key to their construction is a five-dimensional
generalisation of the instanton equation to which they refer as the contact
instanton equation. Subject of this article is the twistor construction of this
equation when formulated on K-contact manifolds and the discussion of its
integrability properties. We also present certain extensions to higher
dimensions and supersymmetric generalisations.Comment: v3: 28 pages, clarifications and references added, version to appear
in JHE
Is decoupling GDP growth from environmental impact possible?
© 2016 Ward et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The argument that human society can decouple economic growth-defined as growth in Gross Domestic Product (GDP)-from growth in environmental impacts is appealing. If such decoupling is possible, it means that GDP growth is a sustainable societal goal. Here we show that the decoupling concept can be interpreted using an easily understood model of economic growth and environmental impact. The simple model is compared to historical data and modelled projections to demonstrate that growth in GDP ultimately cannot be decoupled from growth in material and energy use. It is therefore misleading to develop growth-oriented policy around the expectation that decoupling is possible. We also note that GDP is increasingly seen as a poor proxy for societal wellbeing. GDP growth is therefore a questionable societal goal. Society can sustainably improve wellbeing, including the wellbeing of its natural assets, but only by discarding GDP growth as the goal in favor of more comprehensive measures of societal wellbeing
Microfluidic generation and optical manipulation of ultra-low interfacial tension droplets
In Vivo Quantification of Peroxisome Tethering to Chloroplasts in Tobacco Epidermal Cells Using Optical Tweezers
Theoretical Uncertainties in Electroweak Boson Production Cross Sections at 7, 10, and 14 TeV at the LHC
We present an updated study of the systematic errors in the measurements of
the electroweak boson cross-sections at the LHC for various experimental cuts
for a center of mass energy of 7, 10 and 14 TeV. The size of both electroweak
and NNLO QCD contributions are estimated, together with the systematic error
from the parton distributions. The effects of new versions of the MSTW, CTEQ,
and NNPDF PDFs are considered.Comment: PDFLatex with JHEP3.cls. 22 pages, 43 figures. Version 2 adds the
CT10W PDF set to analysis and updates the final systematic error table and
conclusions, plus several citations and minor wording changes. Version 3 adds
some references on electroweak and mixed QED/QCD corrections. Version 4 adds
more references and acknowledgement
Pathophysiologic Changes in Extracellular pH Modulate Parathyroid Calcium-Sensing Receptor Activity and Secretion via a Histidine-Independent Mechanism
The calcium-sensing receptor (CaR) modulates renal calcium reabsorption and parathyroid hormone (PTH) secretion and is involved in the etiology of secondary hyperparathyroidism in CKD. Supraphysiologic changes in extracellular pH (pH(o)) modulate CaR responsiveness in HEK-293 (CaR-HEK) cells. Therefore, because acidosis and alkalosis are associated with altered PTH secretion in vivo, we examined whether pathophysiologic changes in pH(o) can significantly alter CaR responsiveness in both heterologous and endogenous expression systems and whether this affects PTH secretion. In both CaR-HEK and isolated bovine parathyroid cells, decreasing pH(o) from 7.4 to 7.2 rapidly inhibited CaR-induced intracellular calcium (Ca(2+)(i)) mobilization, whereas raising pH(o) to 7.6 potentiated responsiveness to extracellular calcium (Ca(2+)(o)). Similar pH(o) effects were observed for Ca(2+)(o)-induced extracellular signal-regulated kinase phosphorylation and actin polymerization and for L-Phe-induced Ca(2+)(i) mobilization. Intracellular pH was unaffected by acute 0.4-unit pH(o) changes, and the presence of physiologic albumin concentrations failed to attenuate the pH(o)-mediated effects. None of the individual point mutations created at histidine or cysteine residues in the extracellular domain of CaR attenuated pH(o) sensitivity. Finally, pathophysiologic pH(o) elevation reversibly suppressed PTH secretion from perifused human parathyroid cells, and acidosis transiently increased PTH secretion. Therefore, pathophysiologic pH(o) changes can modulate CaR responsiveness in HEK-293 and parathyroid cells independently of extracellular histidine residues. Specifically, pathophysiologic acidification inhibits CaR activity, thus permitting PTH secretion, whereas alkalinization potentiates CaR activity to suppress PTH secretion. These findings suggest that acid-base disturbances may affect the CaR-mediated control of parathyroid function and calcium metabolism in vivo
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