Spinning bodies in curved space-time

We study the motion of neutral and charged spinning bodies in curved space-time in the test-particle limit. We construct equations of motion using a closed covariant Poisson-Dirac bracket formulation which allows for different choices of the hamiltonian. We derive conditions for the existence of constants of motion and apply the formalism to the case of spherically symmetric space-times. We show that the periastron of a spinning body in a stable orbit in a Schwarzschild or Reissner-Nordstr{\o}m background not only precesses, but also varies radially. By analysing the stability conditions for circular motion we find the innermost stable circular orbit (ISCO) as a function of spin. It turns out that there is an absolute lower limit on the ISCOs for increasing prograde spin. Finally we establish that the equations of motion can also be derived from the Einstein equations using an appropriate energy-momentum tensor for spinning particles.Comment: 26 pages, 5 figures; v2: version accepted for publication; small changes in text and references adde

A concise taxonomy for describing data as an art material.

How can we describe data when used as an art material? As the number of artists using data in their work increases, so too must our ability to describe the material in a way that is understood by both specialist and general audiences alike. In this paper we review existing vocabularies, glossaries, and taxonomies of data, and propose our own concise taxonomy. We present a number of examples of how existing data art works are described, and demonstrate our taxonomy by applying it to these works. To conclude we propose the adoption of this concise taxonomy by artists, critics, and curators, and suggest that on-going refinement of the taxonomy takes place through crowd-sourced knowledge sharing on the web

Enhanced Practical Photosynthetic CO₂ Mitigation

This process is unique in photosynthetic carbon sequestration. An on-site biological sequestration system directly decreases the concentration of carbon-containing compounds in the emissions of fossil generation units. In this process, photosynthetic microbes are attached to a growth surface arranged in a containment chamber that is lit by solar photons. A harvesting system ensures maximum organism growth and rate of CO2 uptake. Soluble carbon and nitrogen concentrations delivered to the cyanobacteria are enhanced, further increasing growth rate and carbon utilization

Flow-Controlling Header

An apparatus and method for holding a membrane, screen or other flexible planar body in tension, while providing a conduit for water or other liquid to flow to the membrane being held. The membrane extends from inside a manifold body that carries the liquid, and the manifold body supports the membrane at one edge while the membrane is pulled in tension. Liquid pressure builds up inside the manifold body, preferably by entering a pressure chamber at the top of the manifold body. At a feeding pressure in the pressure chamber the liquid is distributed to the membrane for microbe growth. The liquid can be elevated to a higher, microbe-harvesting pressure by increasing the pressure in the pressure chamber, thereby deflecting a shim separating the pressure chamber from the membrane. The change in pressure is carried out by manually or automatically opening and closing a conventional water valve

Apparatus and Method for Growing Biological Organisms for Fuel and Other Purposes

A bioreactor apparatus in which a container has sidewalls, a floor and a ceiling defining a chamber that contains a slurry of water, nutrients and photosynthetic microorganisms. A plurality of optical fibers, each of which has a first end disposed outside the chamber and a second end in the mixture. A light collector spaced from the container has light incident on it and focuses the light onto the first ends of the plurality of optical fibers, thereby permitting the light to be conveyed into the mixture to promote photosynthesis. At least one nozzle is in fluid communication with a source of gas, such as exhaust gas from a fossil-fuel burning power plant containing carbon dioxide. The nozzle is disposed in the mixture beneath the second ends of the optical fibers for injecting the gas into the mixture

Adult patients with pulmonary arterial hypertension due to congenital heart disease: a review on advanced medical treatment with bosentan

Pulmonary arterial hypertension (PAH) is a progressive disease with poor survival outcome. PAH is classified by the 2009 updated clinical classification of pulmonary hypertension and a major subgroup is PAH due to congenital heart disease (CHD) with systemic-to-pulmonary shunt. CHD-PAH is a result of systemic-to-pulmonary shunting and chronic increased flow that ultimately results in adaptations of pulmonary vasculature and endothelial dysfunction. The advanced stage is called Eisenmenger syndrome which forms a small percentage (1%) of all CHD patients. Therapies targeted on PAH symptoms are called primary therapy for PAH, but most CHD-PAH patients progress to advanced therapy which is directed at the PAH itself. In CHD-PAH, advanced therapies are extensively investigated for all three major pathways: endothelin-1 receptor antagonists such as bosentan, prostanoids such as epoprostenol and phosphodiesterase 5 inhibitors such as sildenafil. Endpoints in most trials were catheterization hemodynamics, World Health Organization functional class, six-minute walking distance and patient-focused outcomes, based on quality of life questionnaires and Borg dyspnea index. The BREATHE-5 and EARLY study were two important randomized controlled trials showing efficacy of bosentan at short follow-up. Moreover in patients with Eisenmenger syndrome, one recent survival retrospective study with majority of patients on bosentan showed strong survival benefit over conservative therapy. A diversity of prospective cohort and retrospective studies were performed but all with limited data, due to small numbers and heterogeneity of underlying CHD diagnoses. Further larger studies are needed to determine optimal treatment for adults with CHD-PAH. This review focuses on bosentan in CHD-PAH. In particular, we discuss outcome of various clinical trials and compare efficacy and safety of bosentan to other advanced therapies

Dynamic shipments of inventories in shared warehouse and transportation networks

In shared warehouse and transportation networks, dynamic shipments of inventories are carried out based on up-to-date inventory information. This paper studies the effect of network structures on optimal decision-making. We propose a discrete time modeling framework with stochastic demand, capturing a wide variety of network structures. Using Markov decision processes, we obtain optimal order and dynamic shipment decisions for small networks. We compare optimal solutions of different four-node network structures. Results indicate product characteristics significantly influence the effectiveness of network structures. Surprisingly, two-echelon networks are occasionally costlier than any other network. Moreover, dynamic shipments yield considerable gains over static shipments

Necessary Condition Analysis (NCA) Does Exactly What It Should Do When Applied Properly: A Reply to a Comment on NCA

There are two problems with the comment of Thiem about necessary condition analysis (NCA): First, it is based on wrong assumptions about what NCA aims to do. Second, it applies NCA incorrectly. These are critical errors such that the comment’s conclusions about NCA are flawed. Contrary to what the comment states, NCA is a valid method for identifying necessary conditions

Seeing the smart city on Twitter: Colour and the affective territories of becoming smart

This paper pays attention to the immense and febrile field of digital image files which picture the smart city as they circulate on the social media platform Twitter. The paper considers tweeted images as an affective field in which flow and colour are especially generative. This luminescent field is territorialised into different, emergent forms of becoming ‘smart’. The paper identifies these territorialisations in two ways: firstly, by using the data visualisation software ImagePlot to create a visualisation of 9030 tweeted images related to smart cities; and secondly, by responding to the affective pushes of the image files thus visualised. It identifies two colours and three ways of affectively becoming smart: participating in smart, learning about smart, and anticipating smart, which are enacted with different distributions of mostly orange and blue images. The paper thus argues that debates about the power relations embedded in the smart city should consider the particular affective enactment of being smart that happens via social media. More generally, the paper concludes that geographers must pay more attention to the diverse and productive vitalities of social media platforms in urban life and that this will require experiment with methods that are responsive to specific digital qualities

Het effect van verhoogde ammonia concentratie in het water op fysiologie, groei en voeropname van Afrikaanse meerval (Clarias gariepinus)

IMARES onderzocht het effect van de ammoniaconcentratie in het kweekwater op groei, voeropname en fysiologie van Afrikaanse meerval (Clarias gariepinus). Het doel van dit onderzoek was het vaststellen van de maximale ammoniaconcentratie (grenswaarde) waarbij geen negatieve effecten op welzijn van de vis en de productie waar te nemen zijn