Metabolic Rift or Metabolic Shift? Dialectics, Nature, and the World-Historical Method

Abstract In the flowering of Red-Green Thought over the past two decades, metabolic rift thinking is surely one of its most colorful varieties. The metabolic rift has captured the imagination of critical environmental scholars, becoming a shorthand for capitalism’s troubled relations in the web of life. This article pursues an entwined critique and reconstruction: of metabolic rift thinking and the possibilities for a post-Cartesian perspective on historical change, the world-ecology conversation. Far from dismissing metabolic rift thinking, my intention is to affirm its dialectical core. At stake is not merely the mode of explanation within environmental sociology. The impasse of metabolic rift thinking is suggestive of wider problems across the environmental social sciences, now confronted by a double challenge. One of course is the widespread—and reasonable—sense of urgency to evolve modes of thought appropriate to an era of deepening biospheric instability. The second is the widely recognized—but inadequately internalized—understanding that humans are part of nature

Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering

The need to develop and improve sustainable energy resources is of eminent importance due to the finite nature of our fossil fuels. This review paper deals with a third generation renewable energy resource which does not compete with our food resources, cyanobacteria. We discuss the current state of the art in developing different types of bioenergy (ethanol, biodiesel, hydrogen, etc.) from cyanobacteria. The major important biochemical pathways in cyanobacteria are highlighted, and the possibility to influence these pathways to improve the production of specific types of energy forms the major part of this review

Research on Teaching and Learning Probability

This book summarizes the vast amount of research related to teaching and learning probability that has been conducted for more than 50 years in a variety of disciplines. It begins with a synthesis of the most important probability interpretations throughout history: intuitive, classical, frequentist, subjective, logical propensity and axiomatic views. It discusses their possible applications, philosophical problems, as well as their potential and the level of interest they enjoy at different educational levels. Next, the book describes the main features of probabilistic thinking and reasoning, including the contrast to classical logic, probability language features, the role of intuitions, as well as paradoxes and the relevance of modeling. It presents an analysis of the differences between conditioning and causation, the variability expression in data as a sum of random and causal variations, as well as those of probabilistic versus statistical thinking. This is followed by an analysis of probability’s role and main presence in school curricula and an outline of the central expectations in recent curricular guidelines at the primary, secondary and high school level in several countries. This book classifies and discusses in detail the three different research periods on students’ and people’s intuitions and difficulties concerning probability: early research focused on cognitive development, a period of heuristics and biases programs, and the current period marked by a multitude of foci, approaches and theoretical frameworks

Motion Correction of Multi-Frame PET Data

[Otros] Motion correction algorithms are necessary in PET studies where the patient cannot remain totally static. Otherwise, artifacts appear in the final reconstructed image, degrading the spatial resolution or even misplacing the radiation distribution source. In this work we propose a new enhanced motion correction algorithm (EMAF) based on the multiple acquisition frames (MAF). This methodology can be applied to two PET system geometries (a ring and a multi-panel system). Using simulated data, the comparison of static and motion corrected profiles shows minimum differences keeping more than 99% of the events after the process, with a minimal inter-frame error (the maximum range of loss counts is around 0.6%). To measure the quality of the correction method, two error metrics as peak signal to noise ratio (PSNR) and intensity matching precision (IMP) are proposed. A Mini-Derenzo in a ring PET system reveals a remarkable improvement both for these two metrics (44.5 dB and 98.7%) when compared to the uncorrected images (41.1 dB and 56%, respectively). An equivalent analysis for a point-like source also shows a sizeable enhancement both in contrast and resolution (64 dB and 98% versus 62.5 dB and 17.9%, PSNR and IMP correspondingly). The proposed algorithm minimizes the image artifacts and its simplicity, independency of PET configuration system and rapid reconstruction and registration times, makes it a useful tool in preclinical PET studies.This work has been co-financed by the Spanish Government grants TEC2016-79884-C2 and RTC-2016-5186-1, and by the European Union through the European Regional Development Fund (ERDF)Cañizares, G.; Espinós-Morató, H.; Santos, J.; Hernández, Á.; Moliner, L.; Álvarez-Gómez, JM.; González Martínez, AJ.... (2019). Motion Correction of Multi-Frame PET Data. IEEE. 4-8. http://hdl.handle.net/10251/176834S4