Selective pressures on genomes in molecular evolution

We describe the evolution of macromolecules as an information transmission process and apply tools from Shannon information theory to it. This allows us to isolate three independent, competing selective pressures that we term compression, transmission, and neutrality selection. The first two affect genome length: the pressure to conserve resources by compressing the code, and the pressure to acquire additional information that improves the channel, increasing the rate of information transmission into each offspring. Noisy transmission channels (replication with mutations) gives rise to a third pressure that acts on the actual encoding of information; it maximizes the fraction of mutations that are neutral with respect to the phenotype. This neutrality selection has important implications for the evolution of evolvability. We demonstrate each selective pressure in experiments with digital organisms.Comment: 16 pages, 3 figures, to be published in J. theor. Biolog

Contested Visions for Transformation : The Visions of the Green New Deal and the Politics of Technology Assessment, Responsible Research and Innovation, and Sustainability Research

Societal transformations are contested. The goals and visions of transformations, as well as the means and strategies to achieve them, are born in political conflict and power constellations. Which transformations are seen as desirable and possible by democratic majorities changes throughout history. This is the political reality where research for transformations finds itself. Technology assessment (TA), responsible research and innovation (RRI), and sustainability research (SR) are a part of such contestations. They engage in envisioning, debating, analyzing, and evaluating different visions of and options for the future. In this article we turn to visions of the future as a key aspect of societal contestation and the shaping of interfaces between research for transformations and society. Based on the approach of vision assessment developed in TA, we situate TA, RRI, and SR within visions of research and social order. We argue that in these politicized times it is increasingly necessary to understand how research relates to larger visions of society and the contested nature of transformations. We turn to one of the major contemporary visions for societal transformation: The Green New Deal (GND). This vision imagines a large-scale transformation of society and the economy towards sustainability and justice and is currently debated in major political institutions and social movements. It presents an ongoing case of the “making of the future”, which is highly relevant for TA, RRI, and SR. We show how this vision is creating new knowledge and social arrangements and how it is opening up new possibilities for transformational research. The article discusses the implications that a possible further impact of GND visions in politics may have for TA, RRI, and SR, and, relatedly, how expertise and insights from TA, RRI, and SR could significantly add to the GND debate

Lobster Sustainability Measures in Newfoundland: Are They Effective?

The American lobster (Homarus americanus) fishery is a locally reliable inshore commercial fishery in North America with an economic value of CAD 550 million/year in Atlantic Canada. In Newfoundland, this provides 30 million/year in landed value and has considerable socio-economic value (2900 license holders) in rural communities throughout the province. The small boat lobster fishery is at once a regular source of income and part of the cultural integrity of coastal communities in Newfoundland. In recent years concern about the sustainability of this fishery has risen because the percent of harvestable lobsters taken from populations each year is at least 75% in almost all Canadian stocks and in some areas rises to over 95%. The Fisheries Research Conservation Council concluded (FRCC 2007) that in the absence of science data on lobster stocks the fate of future stocks is uncertain if lobsters continue to be harvested at recent rates. Several conservation initiatives were undertaken, with local support, to address these concerns and now form current management practice. These were closed areas [including federally designated marine protected areas (MPAs)], voluntary v-notching, a minimal landing size of 82.5 mm, and the adoption of a maximum size limit in four Lobster Fishing Areas (i.e., a slot fishery). The need for better scientific data on the effectiveness of these measures sparked the FFAW and fish harvesters in Newfoundland to collect data, contribute to the assessment of the stock, and propose a collaborative research project with Memorial University scientists in conjunction with CURRA, the Community-University Research for Recovery Alliance (www.curra.ca). With support from NSERC (Natural Science and Engineering Research Council) a 3 year project was undertaken to address questions being asked by harvesters: are these resource sustainability initiatives (v-notching, closed areas, and a slot fishery) effective?; and specifically, do these measures result in increased egg production and increased size/age distribution, which in turn increase egg production? To establish whether these measures have a science basis we used a central concept in population biology called "reproductive value" to evaluate the effectiveness of these measures. Reproductive value considers not only current egg production, it takes into account the expected future value of the individual to the population. Reproductive value allows us to compare the value of an individual as a commodity with its value to its population

On the behavior of micro-spheres in a hydrogen pellet target

A pellet target produces micro-spheres of different materials, which are used as an internal target for nuclear and particle physics studies. We will describe the pellet hydrogen behavior by means of fluid dynamics and thermodynamics. In particular one aim is to theoretically understand the cooling effect in order to find an effective method to optimize the working conditions of a pellet target. During the droplet formation the evaporative cooling is best described by a multi-droplet diffusion-controlled model, while in vacuum, the evaporation follows the (revised) Hertz-Knudsen formula. Experimental observations compared with calculations clearly indicated the presence of supercooling, the effect of which is discussed as well.Comment: 22 pages, 8 figures (of which two are significantly compressed for easier download

Investigations of a boxed rotor: The STAR II rotor in DLR's test hall

The second Smart Twisting Active Rotor (STAR II) project aims at investigating active twist on a conventional blade design in the DNW-LLF wind tunnel. Prior to the wind tunnel test, the rotor is first tested for correct operation in the rotor test hall at the German Aerospace Center (DLR) in Braunschweig. This test shall ensure that all the instrumentation, but also the active twist, works correctly along with setting up the tracking of the blades before shipping the whole test setup to the DNW-LLF wind tunnel. From previous rotor tests in this hall, it was observed that vibration levels increased drastically above certain thrusts. Since there were no PIV tests carried out within this test chamber, it was decided to carry out CFD simulations to obtain visualizations of the flow and to find the origins of these vibrations. The rotor test hall was approximated by a simple box. With the help of CFD simulations carried out by DLR and JAXA, the initial guess of potential recirculation could be confirmed. The recirculation effect and vibrations become stronger with increasing thrust and therefore limits the maximum thrust in the test hall. This paper details the results of the CFD simulation and presents them along with initial experimental data from the rotor test hall

Recombinant expression and characterization of the endochitinase Chit36-TA from Trichoderma asperellum in Komagataella phaffii for chitin degradation of black soldier fly exuviae

The natural polymer chitin is an abundant source for valuable N-acetylchitooligosaccharides and N-acetylglucosamine applicable in several industries. The endochitinase Chit36-TA from Trichoderma asperellum was recombinantly expressed in Komagataella phaffii for the enzymatic degradation of chitin from unused insect exuviae into N-acetylchitooligosaccharides. Chit36-TA was purified by Ni–NTA affinity chromatography and subsequently biochemically characterized. After deglycosylation, the endochitinase had a molecular weight of 36 kDa. The optimum pH for Chit36-TA was 4.5. The temperature maximum of Chit36-TA was determined to be 50 °C, while it maintained > 93% activity up to 60 °C. The chitinase was thermostable up to 45 °C and exhibited ~ 50% activity after a 15 min incubation at 57 °C. Chit36-TA had a maximum specific enzyme activity of 50 nkat/mg with a Km value of 289 µM with 4-methylumbelliferyl-N,N′,N″-triacetyl-β-chitotrioside as substrate. Most tested cations, organic solvents and reagents were well-tolerated by the endochitinase, except for SDS (1 mM), Cu2+ (10 mM) and Mn2+ (10 mM), which had stronger inhibitory effects with residual activities of 3, 41 and 28%, respectively. With a degree of hydrolysis of 32% applying colloidal shrimp chitin (1% (w/v)) and 12% on insect larvae (1% (w/v)) after 24 h, the endochitinase was found to be suitable for the conversion of colloidal chitin as well as chitin from black soldier fly larvae into water-soluble N-acetylchitooligosaccharides. To prove scalability, a bioreactor process was developed in which a 55-fold higher enzyme activity of 49 µkat/l and a tenfold higher protein expression of 1258 mg/l were achieved

Reform of Unemployment Compensation in Germany : A Nonparametric Bounds Analysis Using Register Data

Economic theory suggests that an extension of the maximum length of entitlement for unemployment benefits increases the duration of unemployment. Empirical results for the reform of the unemployment compensation system in Germany during the 1980s are less clear. The analysis in this paper is motivated by the controversial empirical findings and by recent developments in econometrics for partial identification. We use extensive administrative data with the drawback that registered unemployment is not directly observed. For this reason we bound the reform effect on unemployment duration over different definitions of unemployment. By exploiting the richness of the data we use a nonparametric approach without imposing critical parametric model assumptions. We identify a systematic increase in unemployment duration in response to the reform in samples that amount to less than 15% of the unemployment spells for the treatment group

Alveolar macrophage- derived extracellular vesicles inhibit endosomal fusion of influenza virus

Alveolar macrophages (AMs) and epithelial cells (ECs) are the lone resident lung cells positioned to respond to pathogens at early stages of infection. Extracellular vesicles (EVs) are important vectors of paracrine signaling implicated in a range of (patho)physiologic contexts. Here we demonstrate that AMs, but not ECs, constitutively secrete paracrine activity localized to EVs which inhibits influenza infection of ECs in vitro and in vivo. AMs exposed to cigarette smoke extract lost the inhibitory activity of their secreted EVs. Influenza strains varied in their susceptibility to inhibition by AM- EVs. Only those exhibiting early endosomal escape and high pH of fusion were inhibited via a reduction in endosomal pH. By contrast, strains exhibiting later endosomal escape and lower fusion pH proved resistant to inhibition. These results extend our understanding of how resident AMs participate in host defense and have broader implications in the defense and treatment of pathogens internalized within endosomes.SynopsisExtracellular vesicles are emerging as homeostatic vectors, but poorly understood in influenza infection. Here, alveolar macrophage- derived extracellular vesicles inhibit influenza- endosome fusion in a strain- specific, and pH- dependent manner.Following initial infection of epithelial cells, the influenza virus traffics within host cell endosomes which undergo progressive acidification.Prior to gaining entry into the nucleus for its replication, influenza virus must fuse with endosome membranes- an event initiated at a strain- specific pH.Alveolar macrophages secrete extracellular vesicles which, when internalized by epithelial cells, lead to accelerated acidification of endosomes.Infection of epithelial cells by influenza strains which preferentially fuse with endosome membranes at high pH is inhibited by extracellular vesicles. Infection by influenza strains which fuse at low pH is unaffected by extracellular vesicles.Extracellular vesicles secreted from alveolar macrophages can promote acidification of endosomes in influenza virus- infected epithelial cells to inhibit viral replication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/5/embj2020105057-sup-0002-EVFigs.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/4/embj2020105057_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/3/embj2020105057.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/2/embj2020105057-sup-0001-Appendix.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/1/embj2020105057.reviewer_comments.pd