Practices of place-making through locative media artworks

Peer-reviewedIn recent years, the vast increase in information flows has made it possible to instantly connect location-dependent information with physical spaces. These technologies have provided new forms of the representation of space as much as new forms of perception through tools and techniques used in land surveying, remote sensing, etc. From a critical point of view, pervasive computing, location-based applications, or, in other words, "locative media" provide an interesting framework to understand how these technologies relate to our understanding of space and place. Concretely, we want to examine how the uses of locative media in social-oriented artworks interact with people's sense of place. This article therefore discusses contemporary theories on space related to media and technology with a specific focus on the conceptualization of the notion of place. It also relates these theories to the study of different locative media artworks: Canal Accessible (2006), Bio Mapping (2004), Disappearing Places (2007), and Coffee Deposits (2010). We contend that locative media artworks act upon distinctive ways to understand the mediation of technology in current placemaking practices.En los últimos años, el aumento de los flujos de información ha hecho posible conectar instantáneamente la información dependiente de ubicación con los espacios físicos. Estas tecnologías han facilitado tanto nuevas formas de representación del espacio como nuevas formas de percepción a través de herramientas y técnicas usadas en topografía, teledetección, etc. Desde un punto de vista crítico, la computación ubicua, las aplicaciones de localización, o en otras palabras, los "medios locativos" proporcionan un marco interesante para entender cómo estas tecnologías se relacionan con nuestra comprensión del espacio y el lugar. Concretamente, queremos examinar cómo los usos de los medios locativos en la vida social orientados a obras de arte interactuan con el sentimiento de lugar. En este artículo se analizan tanto las teorías contemporáneas sobre el espacio en relación con los medios de comunicación y la tecnología con un enfoque específico en la conceptualización de la noción de lugar. Estas teorías se refieren también al estudio de diferentes obras de arte de medios locativos: Canal Accesible (2006), Bio Mapping (2004), Lugares Disappearing (2007), y los restos de café (2010). Sostenemos que las obras de arte de medios locativos actuan de maneras distintas para entender la mediación de la tecnología en las prácticas de Placemaking actuales.En els últims anys, l'augment dels fluxos d'informació ha fet possible connectar instantàniament la informació dependent d'ubicació amb els espais físics. Aquestes tecnologies han facilitat tant noves formes de representació de l'espai com noves formes de percepció a través d'eines i tècniques utilitzades en topografia, teledetecció, etc. Des d'un punt de vista crític, la computació ubiqua, les aplicacions de localització o, en altres paraules, els "mitjans locatius" proporcionen un marc interessant per entendre com aquestes tecnologies es relacionen amb la nostra comprensió de l'espai i el lloc. Concretament, volem examinar com els usos dels mitjans locatius en la vida social orientats a obres d'art interactuen amb el sentiment de lloc. En aquest article s'analitzen tant les teories contemporànies sobre l'espai en relació amb els mitjans de comunicació i la tecnologia amb un enfocament específic en la conceptualització de la noció de lloc. Aquestes teories es refereixen també a l'estudi de diferents obres d'art de mitjans locatius: Canal Accessible (2006), Bio Mapping (2004), Llocs Disappearing (2007), i les restes de cafè (2010). Sostenim que les obres d'art de mitjans locatius actuen de maneres diferents per entendre la mediació de la tecnologia en les pràctiques de Placemaking actuals

A priori prediction of aggregation efficiency and rate constant for fluidized bed melt granulation

This paper presents a predictive aggregation rate model for spray fluidized bed melt granulation. The aggregation rate constant was derived from probability analysis of particle–droplet contact combined with time scale analysis of droplet solidification and granule–granule collision rates. The latter was obtained using the principles of kinetic theory of granular flow (KTGF). The predicted aggregation rate constants were validated by comparison with reported experimental data for a range of binder spray rate, binder droplet size and operating granulator temperature. The developed model is particularly useful for predicting particle size distributions and growth using population balance equations (PBEs)

Erratum to: ‘Early prediction of acute kidney injury after transapical and transaortic aortic valve implantation with urinary G1 cell cycle arrest biomarkers’

Background: Acute kidney injury (AKI) is a common complication following transcatheter aortic valve implantation (TAVI) leading to increased mortality and morbidity. Urinary G1 cell cycle arrest proteins TIMP-2 and IGFBP7 have recently been suggested as sensitive biomarkers for early detection of AKI in critically ill patients. However, the precise role of urinary TIMP-2 and IGFBP7 in patients undergoing TAVI is unknown. Methods: In a prospective observational trial, 40 patients undergoing TAVI (either transaortic or transapical) were enrolled. Serial measurements of TIMP-2 and IGFBP7 were performed in the early post interventional course. The primary clinical endpoint was the occurrence of AKI stage 2/3 according to the KDIGO classification. Results: Now we show, that ROC analyses of [TIMP-2]*[IGFBP7] on day one after TAVI reveals a sensitivity of 100 % and a specificity of 90 % for predicting AKI 2/3 (AUC 0.971, 95 % CI 0.914-1.0, SE 0.0299, p = 0.001, cut-off 1.03). In contrast, preoperative and postoperative serum creatinine levels as well as glomerular filtration rate (GFR) and perioperative change in GFR did not show any association with the development of AKI. Furthermore, [TIMP2]*[IGFBP7] remained stable in patients with AKI = 1, but its levels increased significantly as early as 24 h after TAVI in patients who developed AKI 2/3 in the further course (4.77 +/- 3.21 vs. 0.48 +/- 0.68, p = 0.022). Mean patients age was 81.2 +/- 5.6 years, 16 patients were male (40.0 %). 35 patients underwent transapical and five patients transaortic TAVI. 15 patients (37.5 %) developed any kind of AKI;eight patients (20 %) met the primary endpoint and seven patients required renal replacement therapy (RRT) within 72 h after surgery. Conclusion: Early elevation of urinary cell cycle arrest biomarkers after TAVI is associated with the development of postoperative AKI. [TIMP-2]*[ IGFBP7] provides an excellent diagnostic accuracy in the prediction of AKI that is superior to that of serum creatinine

Time scale analysis for fluidized bed melt granulation I: granule-granule and granule-droplet collision rates

Fluidized bed spray granulators (FBMG) are widely used in the process industry for particle size growth; a desirable feature in many products, such as granulated food and medical tablets. In this paper, the first in a series of four discussing the rate of various microscopic events occurring in FBMG, theoretical analysis coupled with CFD simulations have been used to predict granule–granule and droplet–granule collision time scales. The granule–granule collision time scale was derived from principles of kinetic theory of granular flow (KTGF). For the droplet–granule collisions, two limiting models were derived; one is for the case of fast droplet velocity, where the granule velocity is considerable lower than that of the droplet (ballistic model) and another for the case where the droplet is traveling with a velocity similar to the velocity of the granules. The hydrodynamic parameters used in the solution of the above models were obtained from the CFD predictions for a typical spray fluidized bed system. The granule–granule collision rate within an identified spray zone was found to fall approximately within the range of 10-2–10-3 s, while the droplet–granule collision was found to be much faster, however, slowing rapidly (exponentially) when moving away from the spray nozzle tip. Such information, together with the time scale analysis of droplet solidification and spreading, discussed in part II and III of this study, are useful for probability analysis of the various event occurring during a granulation process, which then lead to be better qualitative and, in part IV, quantitative prediction of the aggregation rate

Isoprene and monoterpene fluxes from central amazonian rainforest inferred from tower-based and airborne measurements, and implications on the atmospheric chemistry and the local carbon budget

We estimated the isoprene and monoterpene source strengths of a pristine tropical forest north of Manaus in the central Amazon Basin using three different micrometeorological flux measurement approaches. During the early dry season campaign of the Cooperative LBA Airborne Regional Experiment (LBA-CLAIRE-2001), a tower-based surface layer gradient (SLG) technique was applied simultaneously with a relaxed eddy accumulation (REA) system. Airborne measurements of vertical profiles within and above the convective boundary layer (CBL) were used to estimate fluxes on a landscape scale by application of the mixed layer gradient (MLG) technique. The mean daytime fluxes of organic carbon measured by REA were 2.1 mg C m^−2 h^−1 for isoprene, 0.20 mg C m^−2 h^−1 for α-pinene, and 0.39 mg C m^−2 h^−1 for the sum of monoterpenes. These values are in reasonable agreement with fluxes determined with the SLG approach, which exhibited a higher scatter, as expected for the complex terrain investigated. The observed VOC fluxes are in good agreement with simulations using a single-column chemistry and climate model (SCM).\ud \ud In contrast, the model-derived mixing ratios of VOCs were by far higher than observed, indicating that chemical processes may not be adequately represented in the model. The observed vertical gradients of isoprene and its primary degradation products methyl vinyl ketone (MVK) and methacrolein (MACR) suggest that the oxidation capacity in the tropical CBL is much higher than previously assumed. A simple chemical kinetics model was used to infer OH radical concentrations from the vertical gradients of (MVK+MACR)/isoprene. The estimated range of OH concentrations during the daytime was 3–8×10^6 molecules cm^−3, i.e., an order of magnitude higher than is estimated for the tropical CBL by current state-of-the-art atmospheric chemistry and transport models. The remarkably high OH concentrations were also supported by results of a simple budget analysis, based on the flux-to-lifetime relationship of isoprene within the CBL. Furthermore, VOC fluxes determined with the airborne MLG approach were only in reasonable agreement with those of the tower-based REA and SLG approaches after correction for chemical decay by OH radicals, applying a best estimate OH concentration of 5.5×10^6 molecules cm^−3. The SCM model calculations support relatively high OH concentration estimates after specifically being constrained by the mixing ratios of chemical constituents observed during the campaign.\ud \ud The relevance of the VOC fluxes for the local carbon budget of the tropical rainforest site during the measurements campaign was assessed by comparison with the concurrent CO2 fluxes, estimated by three different methods (eddy correlation, Lagrangian dispersion, and mass budget approach). Depending on the CO2 flux estimate, 1–6% or more of the carbon gained by net ecosystem productivity appeared to be re-emitted through VOC emissions

Green function techniques in the treatment of quantum transport at the molecular scale

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include out-of-equilibrium situations typical for electrical/heat transport as well as to take into account interaction effects in a systematic way. Equilibrium Green function techniques and their extension to non-equilibrium situations via the Keldysh formalism build one of the pillars of current state-of-the-art approaches to quantum transport which have been implemented in both model Hamiltonian formulations and first-principle methodologies. We offer a tutorial overview of the applications of Green functions to deal with some fundamental aspects of charge transport at the nanoscale, mainly focusing on applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references, submitted to Springer series "Lecture Notes in Physics

One year follow-up of the multi-centre European PARTNER transcatheter heart valve study

BackgroundTranscatheter aortic valve implantation (TAVI) has emerged as a new therapeutic option in high-risk patients with severe aortic stenosis.AimsPARTNER EU is the first study to evaluate prospectively the procedural and mid-term outcomes of transfemoral (TF) or transapical (TA) implantation of the Edwards SAPIEN® valve involving a multi-disciplinary approach.Methods and resultsPrimary safety endpoints were 30 days and 6 months mortality. Primary efficacy endpoints were haemodynamic and functional improvement at 12 months. One hundred and thirty patients (61 TF, 69 TA), aged 82.1 ± 5.5 years were included. TA patients had higher logistic EuroSCORE (33.8 vs. 25.7, P <0.0005) and more peripheral disease (49.3 vs. 16.4, P< 0.0001). Procedures were aborted in four TA (5.8) and six TF cases (9.8). Valve implantation was successful in the remaining patients in 95.4 and 96.4, respectively. Thirty days and 6 months survival were 81.2 and 58.0 (TA) and 91.8 and 90.2 (TF). In both groups, mean aortic gradient decreased from 46.9 ± 18.1 to 10.9 ± 5.4 mmHg 6 months post-TAVI. In total, 78.1 and 84.8 of patients experienced significant improvement in New York Heart Association (NYHA) class, whereas 73.9 and 72.7 had improved Kansas City Cardiomyopathy Questionnaire (KCCQ) scores in TA and TF cohorts, respectively.ConclusionThis first team-based multi-centre European TAVI registry shows promising results in high-risk patients treated by TF or TA delivery. Survival rates differ significantly between TF and TA groups and probably reflect the higher risk profile of the TA cohort. Optimal patient screening, approach selection, and device refinement may improve outcomes

Combined in vivo depletion of glycoprotein VI and C-type lectin-like receptor 2 severely compromises hemostasis and abrogates arterial thrombosis in mice

Objective— Platelet inhibition is a major strategy to prevent acute ischemic cardiovascular and cerebrovascular events, which may, however, be associated with an increased bleeding risk. The (hem)immunoreceptor tyrosine activation motif–bearing platelet receptors, glycoprotein VI (GPVI) and C-type lectin-like receptor 2 (CLEC-2), might be promising antithrombotic targets because they can be depleted from circulating platelets by antibody treatment, leading to sustained antithrombotic protection, but only moderately increased bleeding times in mice. Approach and Results— We investigated whether both (hem)immunoreceptor tyrosine activation motif–bearing receptors can be targeted simultaneously and what the in vivo consequences of such a combined therapeutic GPVI/CLEC-2 deficiency are. We demonstrate that isolated targeting of either GPVI or CLEC-2 in vivo does not affect expression or function of the respective other receptor. Moreover, simultaneous treatment with both antibodies resulted in the sustained loss of both GPVI and CLEC-2, while leaving other activation pathways intact. However, GPVI/CLEC-2–depleted mice displayed a dramatic hemostatic defect and profound impairment of arterial thrombus formation. Furthermore, a strongly diminished hemostatic response could also be reproduced in mice genetically lacking GPVI and CLEC-2. Conclusions— These results demonstrate that GPVI and CLEC-2 can be simultaneously downregulated in platelets in vivo and reveal an unexpected functional redundancy of the 2 receptors in hemostasis and thrombosis. These findings may have important implications of the potential use of anti-GPVI and anti–CLEC-2–based agents in the prevention of thrombotic diseases. </jats:sec