ExoPhot: a new approach for the study of photosynthesis viability in exoplanetary systems.

2021 ◽  
Author(s):  
Nuria Fonseca-Bonilla ◽  
Pablo Marcos-Arenal ◽  
Luis Cerdán ◽  
Mercedes Burillo-Villalobos ◽  
Juan García de la Concepción ◽  
...  

<p>NASA and ESA are making plans for the next generation of space telescopes, which should be able to detect biomarkers in the atmospheres of exoplanets in the classical habitable zones around their stars (i.e., the range of separations at which water would be in liquid state on the exoplanet surface). The launch of <em>James Space Webb Telescope</em> is scheduled for October 2021. The main questions are related with the type of organisms producing such possible biomarkers and with the related metabolism? Will autotrophs be the base of the exoplanet ecological pyramid, as on Earth? Will they be phototroph or chemotroph? Will they be photosynthetic? Oxygenic or anoxygenic? Which will their photosynthetic pigments be? ESA’s <em>LIFE</em> or any other new concept for which scientific requirements have not been defined yet might be able to not only detect biomarkers, but to shed light on the actual biochemistry of exoplanet ecosystems. Therefore, investigating the potential variety of photosynthetic systems in exoplanets, either real or to be discovered, is actually very timely, as the requirements of new such telescope concepts are not set yet.</p> <p>The conversion of solar energy to chemical energy through photosynthesis is considered one of the first metabolic routes on planet Earth. Although a low percentage of the solar radiation from our Sun is captured by photosynthesis, this metabolic route provides the energy to drive all the life on Earth. Cyanobacteria are thought to be the first photosynthetic microorganisms on Earth. Subsequent photosynthetic organisms acquired photosynthesis via cyanobacteria endosymbionts, that evolved into chloroplasts in plants (Tomioka & Sugiura 1983).</p> <p>At the same time, photosynthesis modified the atmosphere of the early Earth by producing oxygen as a by-product. The concentration in this gas was increased in the primitive atmosphere, transforming the metabolic possibilities for the rest of organisms and, nowadays, oxygen supports the whole aerobic organisms on the planet. The only requirements that photosynthesis has are the exposure to optical radiation from the corresponding star and the availability of water and carbon dioxide (as a carbon source), making photosynthesis a putative imperative metabolism to be present in any particular radiative planetary system.</p> <p>To deepen into this idea, ExoPhot aims to study the relation between photosynthetic systems on exoplanets around different types of stars (i.e. stellar spectral types) from an astrobiological and multidisciplinary point of view, by focusing on two aspects:</p> <ul> <li>Assess the photosynthetic fitness of a variety of photopigments (either real or hypothetical) as a function of star, exoplanet and atmospheric scenario.</li> <li>Delineate a range of stellar, exoplanet and atmospheric parameters for which photosynthetic activity might be feasible.</li> </ul> <p>To accomplish these goals, we will use state-of-the-art planetary and stellar models to retrieve the radiation signatures at the planet surface for a wide range of exoplanet, atmosphere and host star parameters, and will carry out a quantification of the overlap (convolution) between those spectra with the absorption spectra of photosynthetic pigments, both terrestrial and hypothetical (our own developments on computer-simulated primordial pigments). Here, at the EPSC2021 conference, we present our preliminary results and future work to be developed.</p> <p> </p> <p><em>Bibliography:</em></p> <p>Tomioka, N. & Sugiura, M. The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans. <em>Molecular and General Genetics, </em>1983<em>, 191</em>, 46–50. https://doi.org/10.1007/BF00330888</p> <p> </p>

2020 ◽  
pp. 43-50
Author(s):  
Yauheniya N. Saukova

It is shown that the issues of metrological traceability for extended self-luminous objects with a wide range of brightness have not yet been resolved, since the rank scales of embedded systems are used for processing digital images. For such scales, there is no “fixed” unit, which does not allow you to get reliable results and ensure the unity of measurements. An experiment is described to evaluate the accuracy of determining the intensity (coordinates) of the color of self-luminous objects. In terms of repeatability and intermediate precision compared to the reference measurement method, the color and chromaticity coordinates of self-luminous objects (reference samples) were determined by their multiple digital registration using technical vision systems. The possibilities of the developed methodology for colorimetric studies in hardware and software environments from the point of view of constructing a multidimensional conditional scale are determined.


2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.


2019 ◽  
Author(s):  
Inc. OEAPS

"Academy Journal" is an international, peer-reviewed monthly journal. It is devoted to the publication of original scientific research articles dealing with various academic disciplines.Articles that may be of interest to a wide range of researchers are welcome, and not limited to those who work on specific research subjects."Academy Journal" has an open archive, according to which published articles are available immediately after publication, excluding embargoes.Expert reviewThere is one blind verification process in the journal. All articles will be initially evaluated by the editor for compliance with the journal. Manuscripts that are considered appropriate are then usually sent to at least two independent peer reviewers to assess the scientific quality of the article. The editor is responsible for the final decision on whether to accept or reject the article. The editor's decision is final.The main criterion used in assessing the manuscript submitted to the journal is: uniqueness or innovation in the work from the point of view of the methodology being developed and / or its application to a problem of particular importance in the public sector or service sector and / or the setting in which the efforts, for example, in the developing region of the world. That is, the very model / methodology, application and context of problems, at least one of them must be unique and important.Additional criteria considered in the consideration of the submitted document are its accuracy, organization / presentation (ie logical flow) and recording quality.


1970 ◽  
Vol 1 (3) ◽  
pp. 181-205 ◽  
Author(s):  
ERIK ERIKSSON

The term “stochastic hydrology” implies a statistical approach to hydrologic problems as opposed to classic hydrology which can be considered deterministic in its approach. During the International Hydrology Symposium, held 6-8 September 1967 at Fort Collins, a number of hydrology papers were presented consisting to a large extent of studies on long records of hydrological elements such as river run-off, these being treated as time series in the statistical sense. This approach is, no doubt, of importance for future work especially in relation to prediction problems, and there seems to be no fundamental difficulty for introducing the stochastic concepts into various hydrologic models. There is, however, some developmental work required – not to speak of educational in respect to hydrologists – before the full benefit of the technique is obtained. The present paper is to some extent an exercise in the statistical study of hydrological time series – far from complete – and to some extent an effort to interpret certain features of such time series from a physical point of view. The material used is 30 years of groundwater level observations in an esker south of Uppsala, the observations being discussed recently by Hallgren & Sands-borg (1968).


2018 ◽  
Vol 8 (2) ◽  
pp. 49-73
Author(s):  
Petr Adamec

The core issue of this paper is a quality in the lifelong learning. The aim of the contribution is to describe the area, level and dimensions of quality in a wide range of lifelong learning programs, respectively of further education, which are realized in the sense of § 60 and 60a of the Higher Education Act. The content of the paper also focuses on the theoretical and practical starting points of the quality phenomenon, both from the historical point of view and especially from the perspective of the current focus and concept of university policy in the European and Czech region. The paper also presents the results of a survey focusing on approaches to the quality assurance systems in the concept of components at selected public university.


Author(s):  
Ilana Seager ◽  
Douglas S. Mennin ◽  
Amelia Aldao

Generalized anxiety disorder (GAD) is a debilitating condition characterized by excessive, pervasive, uncontrollable, and paralyzing worries about a wide range of future situations. Individuals with this condition frequently find themselves stuck in worry and tension cycles in futile attempts at reducing uncertainty and increasing control. GAD has been associated with substantial impairments in functioning and reduced quality of life. GAD remains poorly understood, and the long-term efficacy and end-state functioning resulting from treatment are weaker compared to other anxiety disorders. Some treatments (e.g., emotion regulation therapy, acceptance-based behavioral therapy) have improved efficacy, partly by targeting emotional dysfunction. Basic psychopathology research has focused on identifying the role of negative affect in GAD, so little is known about how positive affect is experienced and regulated in this disorder. This is particularly important in light of the overlap of this condition with major depressive disorder, which is characterized by low or suppressed positive emotion. Developing such an understanding is essential to further improve the efficacy of emotion-based treatments. This chapter reviews current and future directions in the study of positive affect in GAD. The chapter reviews the nascent research on positive affect and GAD, then illustrates dimensions of future work.


Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1224
Author(s):  
Stefania Marano ◽  
Cristina Minnelli ◽  
Lorenzo Ripani ◽  
Massimo Marcaccio ◽  
Emiliano Laudadio ◽  
...  

Synthetic nitrone spin-traps are being explored as therapeutic agents for the treatment of a wide range of oxidative stress-related pathologies, including but not limited to stroke, cancer, cardiovascular, and neurodegenerative diseases. In this context, increasing efforts are currently being made to the design and synthesis of new nitrone-based compounds with enhanced efficacy. The most researched nitrones are surely the ones related to α-phenyl-tert-butylnitrone (PBN) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO) derivatives, which have shown to possess potent biological activity in many experimental animal models. However, more recently, nitrones with a benzoxazinic structure (3-aryl-2H-benzo[1,4]oxazin-N-oxides) have been demonstrated to have superior antioxidant activity compared to PBN. In this study, two new benzoxazinic nitrones bearing an electron-withdrawing methoxycarbonyl group on the benzo moiety (in para and meta positions respect to the nitronyl function) were synthesized. Their in vitro antioxidant activity was evaluated by two cellular-based assays (inhibition of AAPH-induced human erythrocyte hemolysis and cell death in human retinal pigmented epithelium (ARPE-19) cells) and a chemical approach by means of the α,α-diphenyl-β-picrylhydrazyl (DPPH) scavenging assay, using both electron paramagnetic resonance (EPR) spectroscopy and UV spectrophotometry. A computational approach was also used to investigate their potential primary mechanism of antioxidant action, as well as to rationalize the effect of functionalization on the nitrones reactivity toward DPPH, chosen as model radical in this study. Further insights were also gathered by exploring the nitrone electrochemical properties via cyclic voltammetry and by studying their kinetic behavior by means of EPR spectroscopy. Results showed that the introduction of an electron-withdrawing group in the phenyl moiety in the para position significantly increased the antioxidant capacity of benzoxazinic nitrones both in cell and cell-free systems. From the mechanistic point of view, the calculated results closely matched the experimental findings, strongly suggesting that the H-atom transfer (HAT) is likely to be the primary mechanism in the DPPH quenching.


2021 ◽  
Vol 14 (3) ◽  
pp. 1-26
Author(s):  
Andrea Asperti ◽  
Stefano Dal Bianco

We provide a syllabification algorithm for the Divine Comedy using techniques from probabilistic and constraint programming. We particularly focus on the synalephe , addressed in terms of the "propensity" of a word to take part in a synalephe with adjacent words. We jointly provide an online vocabulary containing, for each word, information about its syllabification, the location of the tonic accent, and the aforementioned synalephe propensity, on the left and right sides. The algorithm is intrinsically nondeterministic, producing different possible syllabifications for each verse, with different likelihoods; metric constraints relative to accents on the 10th, 4th, and 6th syllables are used to further reduce the solution space. The most likely syllabification is hence returned as output. We believe that this work could be a major milestone for a lot of different investigations. From the point of view of digital humanities it opens new perspectives on computer-assisted analysis of digital sources, comprising automated detection of anomalous and problematic cases, metric clustering of verses and their categorization, or more foundational investigations addressing, e.g., the phonetic roles of consonants and vowels. From the point of view of text processing and deep learning, information about syllabification and the location of accents opens a wide range of exciting perspectives, from the possibility of automatic learning syllabification of words and verses to the improvement of generative models, aware of metric issues, and more respectful of the expected musicality.


Data ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Evgeny Mikhailov ◽  
Daniela Boneva ◽  
Maria Pashentseva

A wide range of astrophysical objects, such as the Sun, galaxies, stars, planets, accretion discs etc., have large-scale magnetic fields. Their generation is often based on the dynamo mechanism, which is connected with joint action of the alpha-effect and differential rotation. They compete with the turbulent diffusion. If the dynamo is intensive enough, the magnetic field grows, else it decays. The magnetic field evolution is described by Steenbeck—Krause—Raedler equations, which are quite difficult to be solved. So, for different objects, specific two-dimensional models are used. As for thin discs (this shape corresponds to galaxies and accretion discs), usually, no-z approximation is used. Some of the partial derivatives are changed by the algebraic expressions, and the solenoidality condition is taken into account as well. The field generation is restricted by the equipartition value and saturates if the field becomes comparable with it. From the point of view of mathematical physics, they can be characterized as stable points of the equations. The field can come to these values monotonously or have oscillations. It depends on the type of the stability of these points, whether it is a node or focus. Here, we study the stability of such points and give examples for astrophysical applications.


2019 ◽  
Vol 15 (S356) ◽  
pp. 96-96
Author(s):  
Eleonora Sani

AbstractI present a detailed study of ionized outflows in a large sample of 650 hard X-ray detected AGN. Taking advantage of the legacy value of the BAT AGN Spectroscopic Survey (BASS, DR1), we are able to reveal the faintest wings of the [OIII] emission lines associated with outflows. The sample allows us to derive the incidence of outflows covering a wide range of AGN bolometric luminosity and test how the outflow parameters are related with various AGN power tracers, such as black hole mass, Eddington ratio, luminosity. I’ll show how ionized outflows are more frequently found in type 1.9 and type 1 AGN (50% and 40%) with respect to the low fraction in type 2 AGN (20%). Within such a framework, I’ll demonstrate how type 2 AGN outflows are almost evenly balanced between blue- and red-shifted winds. This, in strong contrast with type 1 and type 1.9 AGN outflows which are almost exclusively blue-shifted. Finally, I’ll prove how the outflow occurrence is driven by the accretion rate, whereas the dependence of outflow properties with respect to the other AGN power tracers happens to be quite mild.


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