Inversion of spinning sound fields

A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph

A portfolio of natural places:Using a participatory GIS tool to compare the appreciation and use of green spaces inside and outside urban areas by urban residents

Green space at different distances is important for the wellbeing of urban dwellers. However, since these different types of green space are, for the most part, investigated in separate studies, it is difficult to disentangle how the use and appreciation of nearby and more distant nature by urban dwellers is related. To address this issue, we conduct an analysis in which we directly compare the appreciation and use of green spaces at four different spatial levels: neighbourhood, region, national, and world level, for urban residents in the Netherlands, Germany and Denmark. For this we use a quantitative, internet-based, participatory GIS method. The relationship between the use of local and more distant green spaces by urban dwellers has generally been addressed in terms of compensation. Our results indicate that this relationship can also be viewed in a complementary way. Urban residents appear to have a 'portfolio of natural places'. This portfolio consists of favourite places nearby that are rated lower but visited quite often, and natural places that they find highly attractive but are located farther away and visited less often. Local favourite places offer basic access to green and nature while other more distant natural places offer a larger variety of qualities and recreational possibilities. Results also indicate that, in order to meet the needs of urban residents, more than the immediate urban context needs to be considered in urban planning. (C) 2016 Elsevier B.V. All rights reserved

Stream Productivity by Outermost Termination

Streams are infinite sequences over a given data type. A stream specification is a set of equations intended to define a stream. A core property is productivity: unfolding the equations produces the intended stream in the limit. In this paper we show that productivity is equivalent to termination with respect to the balanced outermost strategy of a TRS obtained by adding an additional rule. For specifications not involving branching symbols balancedness is obtained for free, by which tools for proving outermost termination can be used to prove productivity fully automatically

Modelgebruik in de Natuurverkenning 2010-2040

Modellen spelen in de Natuurverkenning 2010-2040 een belangrijke rol bij het uitwerken en doorrekenen van toekomstscenario’s. Waar eerdere verkenningen gebruik maakten van procesmodellen om effecten van omgevingsscenario's door te rekenen, zijn nu met eenvoudige modellen de gevolgen van normatieve opvattingen of wensbeelden ten aanzien van natuur in beeld gebracht. Dit artikel beschrijft deze nieuwe toepassing van modellen en evalueert de meerwaarde ten opzichte van de aanpak in eerdere verdenningen

Downstream processing of Isochrysis galbana: a step towards microalgal biorefinery

An algae-based biorefinery relies on the efficient use of algae biomass through its fractionation of several valuable/bioactive compounds that can be used in industry. If this biorefinery includes green platforms as downstream processing technologies able to fulfill the requirements of green chemistry, it will end-up with sustainable processes. In the present study, a downstream processing platform has been developed to extract bioactive compounds from the microalga Isochrysis galbana using various pressurized green solvents. Extractions were performed in four sequential steps using (1) supercritical CO2 (ScCO2), (2) ScCO2/ethanol (Gas Expanded Liquid, GXL), (3) pure ethanol, and (4) pure water as solvents, respectively. The residue of the extraction step was used as the raw material for the next extraction. Optimization of the ScCO2 extraction was performed by factorial design in order to maximize carotenoid extraction. During the second step, different percentages of ethanol were evaluated (15%, 45% and 75%) in order to maximize the extraction yield of fucoxanthin, the main carotenoid present in this alga; the extraction of polar lipids was also an aim. The third and fourth steps were performed with the objective of recovering fractions with high antioxidant activity, eventually rich in carbohydrates and proteins. The green downstream platform developed in this study produced different extracts with potential for application in the food, pharmaceutical and cosmetic industries. Therefore, a good approach for complete revalorization of the microalgae biomass is proposed, by using processes complying with the green chemistry principlesThe authors acknowledge funding from the EU MIRACLES project (7th Framework Program - Grant Agreement No. 613588). B.G.L. thanks MINECO (Ministerio de Economía y Competitividad) for her Juan de la Cierva postdoctoral research contract. M.H. thanks MINECO for his Ramón y Cajal postdoctoral research contract

Non-invasive assessment of fluid responsiveness to guide fluid therapy in patients with sepsis in the emergency department:a prospective cohort study

BACKGROUND: Little is known about optimal fluid therapy for patients with sepsis without shock who present to the ED. In this study, we aimed to quantify the effect of a fluid challenge on non-invasively measured Cardiac Index (CI) in patients presenting with sepsis without shock. METHODS: In a prospective cohort study, CI, stroke volume (SV) and systemic vascular resistance (SVR) were measured non-invasively in 30 patients presenting with sepsis without shock to the ED of a large teaching hospital in the Netherlands between May 2018 and March 2019 using the ClearSight system. After baseline measurements were performed, a passive leg raise (PLR) was done to simulate a fluid bolus. Measurements were then repeated 30, 60, 90 and 120 s after PLR. Finally, a standardised 500 mL NaCl 0.9% intravenous bolus was administered after which final measurements were done. Fluid responsiveness was defined as >15% increase in CI after a standardised fluid challenge. MEASUREMENTS AND MAIN RESULTS: Seven out of 30 (23%) patients demonstrated a >15% increase in CI after PLR and after a 500 mL fluid bolus. Fluid responders had a higher estimated glomerular filtration rate (eGFR) (64 (44–78) vs 37 (23–47), p=0.009) but otherwise similar patient and treatment characteristics as non-responders. Baseline measurements of cardiac output (CO), CI, SV and SVR were unrelated to PLR fluid responsiveness. The change in CI after PLR was strongly positive correlated to the change in CI after a 500 mL NaCl 0.9% fluid bolus (r=0.88, p<0.001). CONCLUSION: The results of the present study demonstrate that in patients with sepsis in the absence of shock, three out of four patients do not demonstrate a clinically relevant increase in CI after a standardised fluid challenge. Non-invasive CO monitoring in combination with a PLR test has the potential to identify patients who might benefit from fluid resuscitation and may contribute to a better tailored treatment of these patients

Selective and energy efficient extraction of functional proteins from microalgae for food applications

publishedVersionPaid Open Acces

Implicit complexity for coinductive data: a characterization of corecurrence

We propose a framework for reasoning about programs that manipulate coinductive data as well as inductive data. Our approach is based on using equational programs, which support a seamless combination of computation and reasoning, and using productivity (fairness) as the fundamental assertion, rather than bi-simulation. The latter is expressible in terms of the former. As an application to this framework, we give an implicit characterization of corecurrence: a function is definable using corecurrence iff its productivity is provable using coinduction for formulas in which data-predicates do not occur negatively. This is an analog, albeit in weaker form, of a characterization of recurrence (i.e. primitive recursion) in [Leivant, Unipolar induction, TCS 318, 2004].Comment: In Proceedings DICE 2011, arXiv:1201.034