scholarly journals Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life

2020 ◽  
Author(s):  
Eva Mateo-Marti ◽  
Santos Galvez-Martinez ◽  
Carolina Gil-Lozano ◽  
Maria-Paz Zorzano
Keyword(s):  
Nitrogen Fixation ◽  
Iron Sulfide ◽  
Molecular Form ◽  
Essential Element ◽  
Iron Sulfate ◽  
Earth Atmosphere ◽  
Pyrite Surface ◽  
Xps Spectra ◽  
Origin And Evolution ◽  
The Right

<p><strong>Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life</strong></p> <p><strong> </strong></p> <ol> <li><strong> Mateo-Marti <sup>1</sup>, S. Galvez-Martinez<sup>1</sup>, C. Gil-Lozano<sup>1</sup> and María-Paz Zorzano <sup>1,2</sup></strong></li> </ol> <p> </p> <p><sup>1</sup>Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, Madrid, Spain.</p> <p><sup>2</sup>Department of Computer Science, Electrical and Space Engineering, Luleå Universit of Technology, Luleå, Sweden.</p> <p><br /><br />  Nitrogen is an essential element for life, a prerequisite for the origin and evolution of life on Earth, or in any other potentially habitable planet. The molecular form of nitrogen, N<sub>2</sub>, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m2 of ultraviolet irradiance in the 200–400 nm range [1]. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface [Figure 1]. We conclude that UV photocatalysis on pyrite may have been a natural mechanism of prebiotic fixation of nitrogen into ammonium sulfates which is then easily released upon contact with liquid water. This property of pyrite may have been incorporated naturally in the prebiotic chemistry evolution, leading to the inclusion of pyrite nano-clusters as reaction centres to generate ammonia from nitrogen, and then from ammonia to generate ammonium sulfates salts in the presence of oxygen. This process has furthermore implication for the abiotic nitrogen fixation on other planetary environments, and it has critical implications for the habitability of planet and the origin of life.</p> <p> </p> <p><strong>Fig. 1</strong>    Picture of the Planetary Atmosphere and Surfaces Chamber and XPS spectra of the presence of ammonium sulfate on pyrite surface (on the left). Schematic representation of the processes that lead nitrogen fixation on pyrite surface (on the right), (i) by UV photo-catalysis under low pressure conditions (on the top) and, (ii) by the catalytic effect of iron oxide-iron sulfide tandem under visible light conditions and standard earth atmosphere (on the bottom).</p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>[1]   E. Mateo-Marti, S. Galvez-Martinez, C. Gil-Lozano and M-P. Zorzano, Scientific Reports, <strong>9,</strong> 15311 (2019)</p>

scholarly journals Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. Mateo-Marti ◽  
S. Galvez-Martinez ◽  
C. Gil-Lozano ◽  
María-Paz Zorzano
Keyword(s):  
Nitrogen Fixation ◽  
Triple Bond ◽  
Molecular Form ◽  
Iron Sulfate ◽  
Earth Atmosphere ◽  
Pyrite Surface ◽  
X Ray ◽  
Ultraviolet Irradiance ◽  
Emergence Of Life ◽  
Catalytic Effects

Abstract The molecular form of nitrogen, N2, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200–400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.

A Shiny Surface and a Tainted Past

2013 ◽  
Author(s):  
Lars Öhrström
Keyword(s):  
Close Contact ◽  
Essential Element ◽  
Therapeutic Window ◽  
Law Firm ◽  
Award Winning ◽  
Do No Harm ◽  
The Us ◽  
Main Component ◽  
The Right

The day Erin Brockovich was driving in Reno and got hit by another driver, brought her in close contact not only with the bumper of the other car, but eventually also with the US legal system, and this would change her life completely. The day Steven Soderbergh asked Julia Roberts to play the part of Erin Brockovich in the film with the same name didn’t really change her life, one presumes, but it would show the world’s moviegoers and critics that the star and Academy Award winning actress of 1990 was really back on the right track. What is the link between these events? The answer is the element chromium. It was chromium that made law-firm clerk Brockovich start a David-against-Goliath struggle with the California energy conglomerate Pacific Gas and Electric Company, that made director Soderbergh make the blockbuster movie that gave Roberts an Oscar for best female actress in 2000 and revitalized her career. I will try not to spoil the picture for those who have not seen it, because it is well worth watching, but the fact that the good guys win in the end is probably not a surprise anyway. However, the role of chromium in this play is not at all evident. And are the good guys really the good guys? There is usually a proper amount of, and a proper place for, everything, and this includes the elements of the periodic table. The main component in steel, a material which has a role to play in this story, is iron, and while we sometimes have too low a level of this element in our bodies, too much of it will kill us. The same goes for chromium: we can’t live without it. Or so it was thought until very recently. It was supposed to help us to break down and metabolize sugars, and thus ‘chromium deficiency’ could possibly be related to diabetes. Now, while low levels seems to do no harm, there are still possibilities of a therapeutic window—that is, concentrations where it may do some good—but it does not any longer seem to be considered an essential element, although official consensus on this has not yet been proclaimed.

Patients Who Refuse Treatment

2001 ◽  
Author(s):  
Jessica W. Berg ◽  
Paul S. Appelbaum ◽  
Charles W. Lidz ◽  
Lisa S. Parker
Keyword(s):  
Informed Consent ◽  
Essential Element ◽  
Informed Choice ◽  
Sufficient Information ◽  
The Status ◽  
Distorted Version ◽  
The Law ◽  
Right To Refuse Treatment ◽  
The Right ◽  
Right To Refuse

From its inception, the law of informed consent has been based on two premises: first, that a patient has the right to receive sufficient information to make an informed choice about the treatment recommended; and second, that the patient may choose to accept or to decline the physician’s recommendation. The legitimacy of this second premise should be underscored because it is too often belied by the everyday language of medical practice. Getting a consent is medical jargon that implies that patient agreement is the only acceptable outcome. Indeed, the term informed consent itself suggests that patients are expected to agree to be treated rather than to decline treatment. Unless patients are viewed as having the right to say no, as well as yes, and even yes with conditions, much of the rationale for informed consent evaporates. Nonetheless, the medical profession’s reaction to patients who refuse treatment often has been less than optimal. The right to refuse treatment is frequently ignored in practice because it is inconsistent with the history and ethos of medicine (1,2). Physicians are trained to treat illness and to prolong life; situations in which they cannot do either—not because of limitations of knowledge or technology, but because patients or third parties reject their recommendations for care—evoke profound feelings of frustration and even anger. It would not be too much to suggest that these confrontations challenge an essential element of the medical identity. Physicians’ reactions to these situations are varied. Some will contend with patients over their refusal, while others, having assimilated a distorted version of patients’ right to refuse treatment, may too quickly abandon their patients to the consequences of their choices, thereby depriving them of the guidance for which patients traditionally have turned to their physicians. Regardless of the quality of care offered to patients or the degree of concern of those who treat them, some patients will have reasons of their own to decline treatment. Before considering how clinicians might respond to these situations, this chapter reviews the status of the law regarding treatment refusal, surveying a legal landscape that has seen dramatic changes in the last decade.

Doing the Full Monty: Will Publicizing Tax Information Increase Compliance?

2005 ◽  
Vol 18 (1) ◽  
pp. 95-117 ◽  
Author(s):  
Marjorie E. Kornhauser
Keyword(s):  
Essential Element ◽  
Fundamental Principle ◽  
Right To Know ◽  
Negative Attitudes ◽  
The Right To Privacy ◽  
Political Costs ◽  
Tax Laws ◽  
The One ◽  
Definition Of ◽  
The Right

Publicity of information is a fundamental principle of American democracy. Not only is it instrumental in increasing compliance with the laws, a necessity of any government, but also it is an essential element of the right to know-which itself is an aspect of the first amendment right to free speech. Unfortunately, publicity often conflicts with another fundamental right-the right to privacy. In regards to taxes, citizens essentially have two rights to know: a right to know what the tax laws are, and a right to know that these laws are being administered fairly. Publicity in the tax context traditionally means making tax return information public records in an attempt to ensure the fair administration of the tax laws. This type of publicity, however, generates intense hostility because taxpayers perceive it as a huge invasion of their privacy.After examining the pros and cons of traditional publicity of tax information, this Essay suggests that tax publicity be reconceived more broadly. Redefined in the dictionary sense of simply the transmission of information, tax publicity can include a wide array of communications, varying as to content and audience, which can better achieve publicity’s underlying goals with minimal invasions of privacy. A large portion of publicity in this broad sense can be-and should be-educational.The Essay outlines four publicity proposals to stimulate discussion. Three use the expanded definition of publicity and focus on individual taxpayers: an annual tax statement, a short booklet to accompany the 1040, called Know Your Taxes, and an annual W-4. These essentially educational programs should deliver tax information to taxpayers more effectively than currently occurs. The fourth, more controversial, proposal suggests partial publicity-in the traditional sense. It attempts, however, to minimize the customary objections to publicizing tax return information by reducing invasions of privacy.All the proposals will cost money, but probably less than the costs of enforcing compliance only through increased audits and litigation. They may also have psychic and political costs. Although recent studies show that more informed taxpayers are often more compliant, some of the information may trigger negative attitudes which would decrease compliance and/or create pressure for lower taxes.Regardless of whether taxpayer reactions to the increased information are positive or negative, the greater publicity proposed in the Essay could have salutary effects, especially if it occurred in the context of a rational debate by elected officials about tax policy (instead of the current inflammatory rhetorical sound bites). On the one hand, if taxpayers respond positively to publicity, compliance will increase. If they act negatively, and their hostility to taxes increase, at least the publicity will arm them with more precise information that will allow them to focus their objections to the income tax and thereby lobby more effectively for real tax reform.

scholarly journals Origin and Evolution of Nitrogen Fixation Genes on Symbiosis Islands and Plasmid in Bradyrhizobium

2016 ◽  
Vol 31 (3) ◽  
pp. 260-267 ◽  
Author(s):  
Takashi Okubo ◽  
Pongdet Piromyou ◽  
Panlada Tittabutr ◽  
Neung Teaumroong ◽  
Kiwamu Minamisawa
Keyword(s):  
Nitrogen Fixation ◽  
Origin And Evolution ◽  
Nitrogen Fixation Genes

Burn Notice: A Practical Solution for Labels Damaged by Pyritic Specimens

2019 ◽  
Vol 33 (1) ◽  
pp. 18-35
Author(s):  
Lu Allington-Jones ◽  
Kieran Miles ◽  
Lucia Petrera ◽  
Anna Fenlon
Keyword(s):  
Sulfuric Acid ◽  
Natural History ◽  
Iron Sulfide ◽  
Pyrite Oxidation ◽  
Iron Sulfate ◽  
Practical Solution ◽  
High Extent ◽  
Natural History Collections

Abstract Oxidation of pyritic fossils and iron sulfide-bearing minerals is a common problem in natural history collections, and several solutions have been developed to treat and restore these specimens to reduce continued deterioration. Labels associated with these specimens are often also severely damaged by the sulfuric acid and iron sulfate products of pyrite oxidation. This article documents trials undertaken on labels that have been contaminated with these deterioration products to a high extent and are therefore extremely fragile. It recommends a potential salvage method, even for labels that are seemingly impossible to lift out of storage trays. This project exemplifies how techniques developed across different conservation disciplines can benefit natural history collections.

Séquences répétées des génomes de Rhizobium sp. NGR234 et Sinorhizobium meliloti : une analyse comparative par séquençage aléatoire

2001 ◽  
Vol 47 (6) ◽  
pp. 548-558 ◽  
Author(s):  
Xavier Perret ◽  
Jeremy Parsons ◽  
Virginie Viprey ◽  
Kathrin Reichwald ◽  
William J Broughton
Keyword(s):  
Nitrogen Fixation ◽  
Dna Sequences ◽  
Sinorhizobium Meliloti ◽  
Insertion Sequence ◽  
Repeated Dna ◽  
Detailed Structure ◽  
Origin And Evolution ◽  
Prokaryotic Genomes ◽  
Analyse Comparative ◽  
Nitrogen Fixation Genes

Amongst prokaryotic genomes, those of nitrogen-fixing members of the Rhizobiaceae family are relatively large (6–9 Mb), often include mega-plasmids of 1.5–2 Mb, and contain numerous families of repeated DNA sequences. Although most essential nodulation and nitrogen fixation genes are well characterized, these represent only a small fraction of the DNA content. Little is known about the detailed structure of rhizobial genomes. With the development of sequencing techniques and new bio-informatic tools such studies become possible, however. Using the 2275 shot-gun sequences of ANU265 (a derivative of NGR234 cured of pNGR234a), we have identified numerous families of repeats. Amongst these, the 58-bp-long NGRREP-4 represents the third most abundant DNA sequence after the RIME1 and RIME2 repeats, all of which are also found in Sinorhizobium meliloti. Surprisingly, studies on the distribution of these elements showed that in proportion to its size, the chromosome of NGR234 carries many more RIME modules than pNGR234a or pNGR234b. Together with the presence in NGR234 and S. meliloti 1021 of an insertion sequence (IS) element more conserved than essential nodulation and nitrogen fixation genes, these results give new insights into the origin and evolution of rhizobial genomes.Key words: shot-gun, repeats, BIME.

Where is the nitrogen on Mars?

2003 ◽  
Vol 2 (3) ◽  
pp. 217-225 ◽  
Author(s):  
Rocco L. Mancinelli ◽  
Amos Banin
Keyword(s):  
Organic Molecules ◽  
Essential Element ◽  
Crystal Lattices ◽  
Origin And Evolution ◽  
Thermal Escape ◽  
Martian Soil ◽  
Evolution Of Life ◽  
Life On Mars ◽  
Nitrogen Abundance ◽  
Living Organisms

Nitrogen is an essential element for life. Specifically, fixed nitrogen (i.e. NH3, NH4+, NOx or N that is chemically bound to either inorganic or organic molecules and can be released by hydrolysis to form NH3 or NH4+) is useful to living organisms. Nitrogen on present-day Mars has been analysed only in the atmosphere. The inventory is a small fraction of the amount of nitrogen presumed to have been received by the planet during its accretion. Where is the missing nitrogen? Answering this question is crucial for understanding the probability of the origin and evolution of life on Mars, and for its future astrobiological exploration. The two main processes that could have removed nitrogen from the atmosphere include: (1) non-thermal escape of N atoms to space and (2) burial within the regolith as nitrates and ammonium salts. Nitrate would probably be stable in the highly oxidized surface soil of Mars and could have served as an NO3− sink. Such accumulations are observed in certain desert environments on Earth. Some NH4+ nitrogen may also be fixed and stabilized in the soil by inclusion as a structural cation in the crystal lattices of certain phyllosilicates replacing K+. Analysis of the Martian soil for traces of NO3− and NH4+ during future missions will provide important information regarding the nitrogen abundance on Mars. We hypothesize that Mars soil, as typical of extremely dry desert soils on Earth, is likely to contain at least some of the missing nitrogen as nitrate salts and some fixed ammonium bound to aluminosilicate minerals.

New archaeogastropod limpets from hydrothermal vents; Superfamily Lepetodrilacea. II. Anatomy

1988 ◽  
Vol 319 (1192) ◽  
pp. 33-82 ◽  
Keyword(s):  
Hydrothermal Vents ◽  
Mantle Cavity ◽  
Visceral Mass ◽  
Origin And Evolution ◽  
Mode Of Life ◽  
Receptaculum Seminis ◽  
The Right ◽  
High Degree ◽  
Narrow Section ◽  
System Approaches

The anatomy of nine species (two genera) of lepetodrilacean limpets is described and the mode of life deduced therefrom. The unique action of the odontophore sets them apart from all prosobranchs yet known: its initial ventral movement is all but suppressed and the dorsal movement, before withdrawal, exaggerated. This action is facilitated by the freedom of the odontophore from the restraining action of the snout which is controlled by special cephalic levator and retractor muscles. Evidence indicates that the jaws are used as scrubbers, loosening particles from the substratum over the animal’s head which are then collected by the specialized rhipidoglossate radula. This is the only method of feeding in the more primitive of the two genera, Gorgoleptis , in which the possession of a metapodium with an operculum indicates that the transformation to the limpet form is incomplete. All members of the superfamily have a single left gill typically bilamellate and with a pectiniform skeleton. The dorsal (left) lamellae are reduced in number and size, particularly in Lepetodrilus (lost in Lepetodrilus ovalis ), and the ventral (right) ones exaggerated and their numbers increased with the enlargement of the mantle cavity. Although the ciliary bands on the lamellae of Lepetodrilus are as in other prosobranchs, at the tips of the lamellae the frontals and abfrontals expand to form pads and the laterals encircle the tips between them. This unusual modification relates to suspension feeding: the two methods of feeding may proceed concurrently. The nervous system has a high degree of fusion of the postcephalic ganglia. The pedal ganglia are large, their short commissure continuous with a pleural commissure, and the supra- and suboesophageal ganglia are contiguous with the right and left pleurals respectively. Nerves to the mantle and foot are compound. The epipodium is well developed, confined to the region of the foot in Gorgoleptis and with elongated tentacles, but spreading on to the head and forming a fold surrounding the base of each cephalic tentacle in Lepetodrilus , which has shorter tentacles round the foot; cilia on the right cephalic fold pass particulate matter from the mantle cavity to the mouth. The penis of Lepetodrilus is also of epipodial origin as opposed to its development from the left side of the snout in Gorgoleptis. In both genera a right pallial tentacle is associated with the exhalant passage from the mantle cavity, though this is greatly reduced in Lepetodrilus . The shell of Gorgoleptis species indicates that these limpets have followed a different evolutionary course from that of Lepetodrilus in that the columellar lip remains as an integral part of the peristome. In species of both genera the mantle edge has two folds, the inner probably represents the fusion of the inner and middle folds of zeugobranch limpets: the remoteness of the periostracal and shell secreting areas results in an inturned band of periostracum particularly broad in Lepetodrilus species. In each, the shell muscle is approximately bilaterally symmetrical, but details of its constituent parts, pedal and pallial, differ. In addition to the bilamellate gill and epipodium, the alimentary, circulatory, nervous and excretory systems indicate that relationships are at the archaeogastropod level. Although similar to the trochaceans, these limpets differ from them in a number of respects. The reproductive system approaches that of monotocardians in the length of the gonadial duct, which in the male is a vesicula seminalis; in the separation of that part of the right kidney through which gametes pass to the urinogenital opening; in the presence of a prostate and penis in the male, and in the female Lepetodrilus of a receptaculum seminis. The female has no hypertrophied pallial oviduct, and eggs with no secondary investments are apparently fertilized in the mantle cavity, and then shed. Although the anatomy of Neomphalus indicates that it had a different origin and evolution from the more conservative lepetodrilaceans, all these prosobranchs share a common characteristic in the attainment of the limpet form by having a narrow section between the enlarged head and the visceral mass marked by the end of the oesophageal pouches and tight chiastoneury.

Digital Citizenship and the Right to Identity in Australia

2013 ◽  
Vol 41 (3) ◽  
pp. 557-584
Author(s):  
Clare Sullivan
Keyword(s):  
Traditional Approach ◽  
Essential Element ◽  
Digital Citizenship ◽  
System Failure ◽  
Digital Information ◽  
Digital Identity ◽  
Digital Era ◽  
The Right ◽  
Formal Recognition ◽  
New System

Australia has announced the need to review the distribution of responsibility among individuals, businesses and governments, as a consequence of the move to digital citizenship. Australia has formally framed the issues in these terms and has opened dialogue between government and citizens regarding responsibilities for the use and protection of digital identity. This article examines digital citizenship in Australia and considers the implications for individuals, government and the private sector of the requirement for an individual to use his/her digital identity for transactions. The features and functions of digital identity are examined, and the consequences for individuals, business and government of system failure are considered. The analysis shows that, while there are consequences for all, individuals are most affected. The author argues that the traditional approach of relying on privacy for protection is inadequate in these circumstances. Privacy, by its nature, cannot adequately protect the part of digital identity which is required for transactions. The argument presented is that, unlike privacy, the right to identity can protect the set of digital information required for transactions. Considering the new system is literally being imposed by government, the inherent vulnerabilities of the system, and the consequences of system failure for individuals, formal recognition of the right to identity is an essential element of accountable and responsible governance. Whilst in time the right to identity in this context may be recognised by the courts, the author argues that legislative recognition and protection of an individual's right to digital identity is needed now as a key component of the distribution of responsibility in this new digital era.

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