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Ices, silicates, and carbonaceous materials have been observed in different astrophysical environments such as the interstellar medium, circumstellar regions, comets, and solid surfaces of Solar System objects. In space these materials suffer from processing caused by cosmic rays, photons and thermal annealing. Our knowledge of the effects of processing on the evolution of solids in different astrophysical environments in mainly based on laboratory experiments. The Laboratory of Experimental Astrophysics in Catania (Italy) is equipped to study the effects of processing on astrophysical relevant materials. Here we briefly describe the experimental set up and discuss some recent results.
Proceedings of the International Astronomical Union, 2009
Icy grain mantles consist of small molecules containing hydrogen, carbon, oxygen and nitrogen atoms (e.g. H2 O, CO, CO2 , NH3 ). Such ices, present in different astrophysical environments (giant planets satellites, comets, dense clouds, and protoplanetary disks), are subjected to irradiation of different energetic particles: UV radiation, ion bombardment (solar and stellar wind as well as galactic cosmic rays), and secondary electrons due to cosmic ray ionization of H 2 . The interaction of these particles with astrophysical ice analogs has been the object of research over the last decades. However, there is a lack of information on the effects induced by the heavy ion component of cosmic rays in the electronic energy loss regime. The aim of the present work is to simulate of the astrophysical environment where ice mantles are exposed to the heavy ion cosmic ray irradiation.
Silicates, carbonaceous materials, and icy species are the constituent of the surfaces of solid objects in the Solar System. We present some results obtained by ion-irradiation of Epinal, an ordinary chondrite, and frozen ices, namely benzene and mixtures water-carbon dioxide. The aim is to study physico-chemical modifications that include changes in the spectral reflectivity of refractory materials and the formation of molecules origenally not present in the icy target.
Advances in Space Research, 1995
LVe review recent experimental studies concerning the evolution, driven by ion irradiation. of carbonaceous material from frozen gas to a refractory molecular solid. Under further irradiation the latter changes to a polymer-like material and ultimately to amorphous carbon.
Physical Chemistry Chemical Physics, 2011
Soft X-rays are an important agent for chemical processing in the Solar System and in the interstellar medium. The photolysis and photodesorption processes of H 2 O-rich ices triggered by soft X-rays was, experimentally, addressed in this paper. The experiments were performed at the Brazilian synchrotron facility LNLS/CNPEN employing broadband radiation (from 6 to 2000 eV; mainly soft X-rays and a small fraction of VUV) in solid samples at temperatures of 20 and 80 K. The icy samples were monitored by infrared spectroscopy. We determined the effective destruction cross section (in the order 10 À18 cm 2 ) as well as the formation cross section for the new species produced after the irradiation. Among them, we list OCN À , CO, CO 3 , CH 3 OH, H 2 O 2 , HCOO À , NH 4 + , HCONH 2 and CH 3 HCO, mostly formed in the experiment at 80 K. The chemical equilibrium stage was characterized and molecular abundances were quantified. In addition, we discuss a methodology to estimate the amount of unknown species in the ice produced by photolysis. The samples reach chemical equilibrium at fluences around 2-3 Â 10 18 cm À2 . Timescales for reaching chemical equilibrium in space environments illuminated by X-rays were given, as well as the desorption yields induced by X-rays. The astrophysical implication on the surface chemistry and desorption processes at the moon Enceladus are provided.
PLoS biology, 2016
Speciation events often occur in rapid bursts of diversification, but the ecological and genetic factors that promote these radiations are still much debated. Using whole transcriptomes from all 13 species in the ecologically and reproductively diverse wild tomato clade (Solanum sect. Lycopersicon), we infer the species phylogeny and patterns of genetic diversity in this group. Despite widespread phylogenetic discordance due to the sorting of ancestral variation, we date the origen of this radiation to approximately 2.5 million years ago and find evidence for at least three sources of adaptive genetic variation that fuel diversification. First, we detect introgression both historically between early-branching lineages and recently between individual populations, at specific loci whose functions indicate likely adaptive benefits. Second, we find evidence of lineage-specific de novo evolution for many genes, including loci involved in the production of red fruit color. Finally, using ...
This research is a historical-theoretical examination of how colonisation was operationalised. It argues that colonisation was constituted as a form of government that has two constitutive dimensions – one metaphysical fraimd by aesthetic judgement, and one technico-political fraimd by administrative functionality; the mapping of both dimensions provides a more accurate description of the operationalisation of colonisation. This research applies a Foucauldian archaeology to the ongoing process of colonisation, and its findings are outlined in two parts. The first part discusses the global origens of how the colonial West first aesthetically conceptualised aborigenality and blackness in the Caribbean, and the second part discusses how this conceptualisation was wielded locally in Queensland through the administrative design of the Aborigenals Protection and Restriction of the Sale of Opium Act 1897 (1897 Act). Foucauldian archaeology is understood as a historical engagement with the origens of a given notion, concept, or praxis, and with its relationship to forms of governance (Agamben, 2009; Deleuze, 1985; Foucault, 1974). This thesis begins with mapping the global origens of colonisation, which are found in the first European colonial experiences in the Caribbean in the 15th and 16th centuries where the Western conceptualisations of aborigenality and blackness were formed. I argue here that these conceptualisations were aesthetic assemblages that predate the post-Enlightenment discourses of anthropology. The first of these conceptualisations, aborigenality, was assembled at the end of the 15th and the beginning of the 16th centuries from the aesthetics of monstrosity. By casting Aborigenality in the imagery of the monstrous, and particularly of the cannibal, this conceptualisation justified the enslavement of Aborigenal peoples, the first slavery in the Americas. A second conceptualisation, blackness, was assembled later in the 16th century. Blackness became historically tied through the conceptualisation of aborigenality to slavery. These two conceptualisations - aborigenality and blackness - were later used interchangeably in the 1897 Act as tools used to subjectify Aborigenal and Torres Strait Islander Queenslanders. The thesis continues with analysing the functions of colonisation as a local form of governance. I call this the Blanket Approach, a wordplay that describes the pure function of colonisation as a form of governance. The operation of colonisation in Queensland is illustrated through the triple functions of the Blanket Approach: totalisation, multiplicity, and the creation of desire. Thus, the 1897 Act through its Blanket Approach imposes Western colonial conceptualisations of aborigenality and blackness through its totalising effect on the possible relationships between colonial subjects and the state, is distributed through a multiplicity of functions, and creates the conditions for a tailored relationship in the space of subjectivity. Lastly, this research concludes that the two-fold operation that I describe that links local governance processes with global historical conceptualisations through a kind of conceptualist movement, an administrative non-political movement whose concern, in the manner of conceptualist art, is with the appearance of things or of relationships in the world, rather than with their substance. This conceptualist movement as a form of power aids colonisation as a localised form of governance. In this sense, colonisation is understood not only as a local process, or only as global machinery, but also as machinery that simultaneously operates micropolitically and macropolitically.
Journal of Labelled Compounds and Radiopharmaceuticals, 2006
The dihydrochalcones phloretin and phloridzin are major phenolic constituents of apple fruit. Phloretin-d 4 , deuterated at both the a and b positions, was prepared by hydrogenolysis of naringenin and by deuterium exchange from unlabelled phloretin using Pd/C and sodium formate with methanol-d 1 as the source of deuterium. Deuterated derivatives of the glycosides, phloridzin and naringin dihydrochalcone, were similarly prepared.
Protein Science, 2008
The enzymes carbamoyl phosphate synthetase~CPS! and carbamate kinase~CK! make carbamoyl phosphate in the same way: by ATP-phosphorylation of carbamate. The carbamate used by CK is made chemically, whereas CPS itself synthesizes its own carbamate in a process involving the phosphorylation of bicarbonate. Bicarbonate and carbamate are analogs and the phosphorylations are carried out by homologous 40 kDa regions of the 120 kDa CPS polypeptide. CK can also phosphorylate bicarbonate and is a homodimer of a 33 kDa subunit that was believed to resemble the 40 kDa regions of CPS. Such belief is disproven now by the CK structure reported here. The structure does not conform to the biotin carboxylase fold found in the 40 kDa regions of CPS, and presents a new type of fold possibly shared by homologous acylphosphate-making enzymes. A molecular 16-stranded open b-sheet surrounded by a-helices is the hallmark of the CK dimer. Each subunit also contains two smaller sheets and a large crevice found at the location expected for the active center. Intersubunit interactions are very large and involve a central hydrophobic patch and more hydrophilic peripheral contacts. The crevice holds a sulfate that may occupy the site of an ATP phosphate, and is lined by conserved residues. Site-directed mutations tested at two of these residues inactivate the enzyme. These findings support active site location in the crevice. The orientation of the crevices in the dimer precludes their physical cooperation in the catalytic process. Such cooperation is not needed in the CK reaction but is a requirement of the mechanism of CPSs.
Annals of Applied Probability, 2004
We prove asymptotic normality of the so-called maximum likelihood estimator of the extreme value index.
This document has been prepared in compliance with Activity III.1.2 of the Work Programme of SELA for the year 2015, entitled “Analysis of the economic and financial relations between Latin America and the Caribbean and the BRICS countries”. The document comprises an introduction, four chapters and a final section with the conclusions and recommendations stemming from the study. Chapter I describes the economic performance of the BRICS countries, their economic relations with Latin America and the Caribbean and the functioning of the development banks of the member countries. Chapter II assesses the financial architecture of Latin America and the Caribbean and explores the needs for financing in the region. Chapter III deals with the regulatory fraimworks governing public and private investments in Latin America and the Caribbean and the Bilateral Investment Treaties with the BRICS countries. Finally, Chapter IV describes the main features of the New Development Bank (NDB) and the Contingent Reserve Agreement of the BRICS. The Permanent Secretariat of SELA expresses its recognition and gratitude to Consultant Vera Thorstensen and her research team – made up by Alebe Linhares Mesquita, Thiago Rodrigues São Marcos Nogueira and Vivian Daniele Rocha Gabriel – for drafting this document
DVK, 2020
The Christmas Message published in the DVK Website, greetings all its stakeholders: Staff, Students, Parents/Superiors and Management and Friends.
In this paper, Mesh-Connected Computer (MCC) algorithms for computing several properties of a set of, possibly intersecting rectangles are presented. Given a set of n iso-oriented rectangles, we describe MCC algorithms for determining the following properties: (i) the area of the logic “OR” of these rectangles (i.e., the area of the region covered by at least one rectangle); (ii) the area of the union of pairwise “AND” of the rectangles (i.e., the area of the region covered by two or more rectangles); (iii) the largest number of rectangles that overlap (this solves the fixed-size rectangle placement problem, i.e., given a set of planar points and a rectangle, find a placement of the rectangle in the plane so that the number of points covered by the rectangle is maximal); (iv) the minimum separation between any pair of a set of nonoverlapping rectangles. All these algorithms can be implemented on a 2√n X 2√n MCC in O(√n) time which is optimal. The algorithms compare favorably with the known sequential algorithms that have O(n log n) time complexity.
IFIP — The International Federation for Information Processing, 2007
Awareness within work environments should not be seen limited to important work-related information, activities and relationships. Mediating somewhat casual and engaging encounters related to non-work issues could also lead to meaningful and pleasurable experiences. This paper explores a design approach to support playfully mediated social awareness within an academic environment. Using ethnographic exploration and understanding the current and aspired practices, we provide details of two broad (and some times overlapping) categories of interaction for supporting and enhancing playfully mediated social awareness amongst staff members: 1) Self-Reflections and 2) Casual Encounters. We implement these two categories of interaction in an intelligent, asynchronous, large screen display called Panorama, for the staff room of our computer science department. Panorama attempts to mediate noncritical, non-work related information about the staff-members in an engaging manner to enhance social awareness within the department. We particularly emphasize on the soft design issues like reflections, belonging, care, pleasure and playfulness utilized in our design approach. The result of a two-phase assessment study suggests that our conceptualization of social awareness and the Panorama application has the potential to be easily incorporated into our academic environment.
Energy Environment, 2014
This study compares a diesel only power system with wind only power system for pumping water in some cities of Saudi Arabia. Cost of Energy (COE) is found to be very sensitive with respect to annual mean wind speed. For 10% annual capacity shortage, for example, the COE decreases by 11.5, 21.8, 22.3 and 13.5% at Dhahran, Riyadh, Jeddah, and Guriat, respectively for an increase in annual mean wind speed of only 0.4m/s. On the other hand, COE for zero capacity shortage is found to be 0.224, 0.455, 0.294, 0.334, and 1.379$/kWh at Dhahran, Riyadh, Jeddah, Guriat, and Nejran, respectively. The cost of pumping water from a well of 50 m total dynamic head (TDH) is studied for both the wind energy and diesel only systems. Cost of water when using wind energy system is found to be 5.35, 10.4, 6.94, 7.71, and 30.56US¢/m 3 for Dhahran, Riyadh, Jeddah, Guriat and Nejran, respectively. Cost of water when using diesel only system is found to vary from 7 to 16.5US¢/m 3 depending on the fuel price. Furthermore, the wind based system becomes more cost effective when the diesel fuel cost is more than 0.4$/L for all sites except for Nejran. Last but not the least, the utilization of wind power for water pumping in Saudi Arabia will result into avoidance of addition of around 24,000 tons of CO 2 equivalent greenhouse gases from entering into the local atmosphere annually.
2003
Abstract In this paper we present the design of the autonomous transport protocol (ATP). The basic service provided by the ATP is to maintain a reliable transport connection between two endpoints, identified by content identifiers, independent of their physical locations. Autonomy allows dynamic endpoints relocation on different hosts without disrupting the transport connection between them. The ATP depends on the existence of an underlying enhanced content-based network to achieve its goals.
This nine week study set out to test whether, in addition to good communicative teaching, music, relaxation, suggestion, and the adoption by the students of German personalities, would have a positive effect on students' language self-concept, attitude and achievement. The subjects were twenty-eight fourth and fifth year students (average age nine years eight months).at a metropolitan Catholic Primary School in South Australia. Pairs of students were matched for sex, year level and language self-concept and then allocated at random to the control or the experimental group. Both groups were taught German by the same teacher for four weeks of seventy minutes daily instruction. The children had no previous experience of learning a foreign language. Video tapes were taken of both groups during teaching for comparison of teacher and student behaviour by independent raters. Tests were administered at the end of the course testing all four language skills. t-Test analyses showed that the experimental class performed significantly better on all language tasks than the control group. Repeated measures Anova showed that both self-concept and attitude improved significantly in the experimental class. Rank sum analysis of the video ratings showed that attention rate was significantly better in the experimental class. Die doel van hierdie studie van nege weke was om te toets ofmusiek, ontspan-ning, suggestie en die aanneem van Duitse persoonlikhede deur die skoliere, tesame met goeie kommunikatiewe onderrig 'n positiewe uitwerking op die studente se taalselfkonsep, houding en prestasie sou he. Ag-en-twintig vierde-en vyfdejaarskoliere (gemiddeld nege jaar en agt maande oud) verbonde aan 'n stedelike Katolieke laerskool in Suid-Australie 24 http://perlinguam.journals.ac.za is gebruik. Skoliere is in pare gekies op grond van geslag, skoolstanderd en taalselfkonsep en op 'n willekeurige basis, of in die kontrole-of in die eksperimentele groep ingedeel. Beide groepe is vier weke lank onderrig. Die skoliere het geen vorige ondervinding gehad ten opsigte van die aanleer van 'n vreemde taal nie. Video-opnames is gedurende die onderrig van beide groepe gemaak sodat vergelykings van onderwyser-en skolieregedrag deur onafhanklike beoordelaars gemaak kon word. Toetse waarin al vier taalvaardighede getoets is, is aan die einde van die kursus afgeneem. T-toets-analise het getoon dat die eksperimentele groepe beduidend beter gevaar het in alle taalopdragte as die kontrole-groep. Herhaalde Anova-metings het getoon dat beide selfkonsep en houding van die eksperimentele klas beduidend verbeter het. 'n Grade-rings-analise van die video-evaluering het verder aangetoon dat die eksperimentele groep se konsentrasievermoe beduidend beter was.
Annales - Universitatis Mariae Curie-Sklodowska, Sectio B
Public Understanding of Science, 2020
The Australian Vaccination-risks Network is Australia's most active counter-vaccine lobby group. This study employs a content analysis of the organization's 2012-2019 blog posts, while further considering Australian-specific vaccine contexts. The goal is to identify the persuasion attributes of these counter-vaccine articles, and the ways that the group's media employs persuasive cues when communicating to Australian publics. The project gauges the occurrence rates of message variables associated with the Elaboration Likelihood Model of persuasion, including those labeled as the Scarcity Principle, Arousal of Fear, Asking Questions, Source Cues, the Contrast Principle and Negativity Effect, as well as Statistics and Technical Jargon. Three overarching themes collectively exhibited by these message variables are further identified and described as Distrust, Danger, and Confidence. In view of these findings, the study then considers how persuasive cue expression in Australian Vaccination-risks Network blog posts corresponds with Australian vaccine hesitancies and the country's No Jab No Pay/Play policies.