bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survival of gas phase amino acids and nucleobases in space radiation conditions
Authors: Pilling S. , Andrade D. P. P. , de Castilho R. B. , Cavasso-Filho R. L. , Lago A. F. , Coutinho L. H. , de Souza G. G. B. , Boechat-Roberty H. M. , de Brito A. Naves 
Published: October 2008

AbstractWe present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interpla-netary radiation analogs conditions. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using a photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70–80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.
Formation of alcohols on ice surfaces
Authors: Cuppen H. M. , Fuchs G. W. , Ioppolo S. , Bisschop S. E. , Öberg K. I. , van Dishoeck E. F. , Linnartz H. 
Published: October 2008

AbstractAs the number of detections of complex molecules keeps increasing, answering the question about their formation becomes more pressing. Many of the saturated organic molecules are found to have a very low gas phase formation rate and are therefore thought to be formed on the icy surfaces of dust grains. In the Sackler Laboratory for Astrophysics we started a systematic study of the surface reaction routes that have been suggested over the years. Here we present the experimental results on the formation of methanol and ethanol by hydrogenation reactions of carbon monoxide and acetaldehyde ice. Computer simulations of the surface processes under similar conditions using the continuous-time random-walk Monte Carlo technique reveal some of the underlying physical processes. A better understanding of the physical conditions in which these molecules are formed can help in the interpretation of the observational results. The CO hydrogenation results will appear in detail in Fuchs et al. (2008). For more details on ethanol formation we refer to Bisschop et al. (2007).
Electronic spectra of carbon chains and rings: Astrophysical relevance?
Authors: Jochnowitz Evan B. , Maier John P. 
Published: October 2008

AbstractOur research has focused on the measurement of the electronic spectra of unstable molecules which are presumed to be of relevance to astrophysical observations. Among these are the carbon chains and their ions. Thus we have been using and developing a number of spectroscopic methods to determine their spectra in the gas phase, including absorption via cavity ring-down and REMPI methods. The species are produced in supersonic jets coupled with discharge and laser ablation sources. With the successful laboratory detection of the electronic spectra of a number of key species, such as bare carbon chains Cnn=4,5, comparisons with astrophysical data could be made which lead to interesting implications for the future search for the species which could be responsible for the diffuse interstellar bands. Among the recent relevant observations in the laboratory have been the electronic spectra of carbon rings, Cnn=14,18,22, the development of a method to study transitions in mass-selected ions collisionally relaxed to 20 K and held in a 22-pole radiofrequency trap, and the study of metal containing carbon chains.
In situ observation of structural alteration process of filmy quenched carbonaceous composite
Authors: Kumamoto Akihito , Kimura Yuki , Kaito Chihiro , Wada Setsuko 
Published: October 2008

AbstractThe thermal alteration process of filmy quenched carbonaceous composite (filmy QCC) has been studied in situ by high-resolution transmission electron microscopy (HRTEM). HRTEM images of the as-prepared filmy QCC showed the typical amorphous carbon film structure. By heating above 300 °C, the structural alteration takes place. Curled graphene structure started to appear at 300 °C. Distorted onion-like structure similar to dark QCC appeared above 500 to 700 °C. The distorted onion-like structure that appears at 700 °C after heating for 30 minutes also appeared by heating at 450 °C for 2 hours.
Reactions of aromatics in space and connections to the carbon chemistry of Solar System materials
Authors: Bernstein Max 
Published: October 2008

AbstractPolycyclic aromatic hydrocarbons (PAHs) and related aromatic materials are thought to be the most abudant class of organic carbon in the universe, being present in virtually all phases of the ISM, and abundant in carbonaceous meteorites and asteroid and comet dust. The basic PAH skeleton is proposed to have formed in outflows of carbon rich stars, and isotopic measurements of extraterrestrial graphitic carbon is consistent with this notion. However, functionalized aromatics bearing oxygen atoms, aliphatic domains, and deuterium enrichments have been extracted from meteorites and more recently been measured in IDPs and Stardust retuned comet samples. Exposure of remnant circumstellar PAHs to energetic processing at low temperature in the presense of H2O is the most parsimonious explanation for these observations.We will present laboratory infrared spectra of various aromatic species and PAH cations in solid H2O under conditions relevant for comparsion to absorptions attributed to PAHs observed towards objects embedded in dense clouds. In addition, we shall describe the reactions of PAHs under these conditions in the lab when they are exposed to energetic processing. Finally, we will propose a mechanism, and make specific predictions regarding the structures and distribution of deuterium that should be observed in extraterrestrial samples if low temperature ice radiation chemistry is playing a role in the formation of the molecules seen in Solar System materials.
Optical and chemical properties of tholins
Authors: Khare Bishun N. , McKay Christopher P. , Cruikshank Dale P. , Sekine Yasuhito , Wilhite Patrick , Ishihara Tomoko 
Published: October 2008

AbstractFor over three decades tholins have been synthesized from mixtures of the cosmically abundant gases CH4, C2H6, NH3, H2O, HCHO, N2, and H2, previously in the Laboratory for Planetary Studies at Cornell University and in recent years at NASA Ames Research Center. The tholin synthesized by UV light or spark discharge on sequential and non-sequential pyrolysis GC-MS revealed hundreds of compounds, and on hydrolysis produced a large number of amino acids including racemic protein amino acids. Optical constants have been measured of many of the tholins, tholins produced from a condensed mixture of water and ethane at 77 K, poly HCN, and Titan tholin produced on electrical discharge through a mixture of 90% N2 and 10% CH4. Its optical constants were measured from soft x-rays to microwave for the first time.Here we report the absorption properties of Titan tholin that is produced in the temperature range 135 to 178 K where tholins are produced by magnetospheric charged particles, then pass through lower temperature at 70 K and finally to the ground at 95 K. While descending to the ground, it gets coated and processed on the way by other sources of energy such as long UV and cosmic rays. It is therefore expected that the stable products of CH4 photolysis react with Titan tholin to recycle the CH4 supply in Titan's atmosphere. Furthermore, the reactions of gaseous C2H6 with the reactive materials on the surface of the tholin could incorporate atmospheric C2H6 into the tholin and therefore might reduce the deposition rate of C2H6 onto the ground of Titan.
Photochemistry of interstellar/circumstellar ices as a contributor to the complex organics in meteorites
Authors: Nuevo Michel , Sandford Scott A. 
Published: October 2008

AbstractThe UV irradiation of interstellar/circumstellar ice analogs is known to lead to the formation of organic compounds such as amino acids and maybe nucleobases. In this work, the mechanisms of formation and distribution of amino acids, chosen as tracers for the organic compounds formed in such experiments, are studied and compared with meteoritic data.
Radiation chemistry approach to the study of ice analogs
Authors: Colin-Garcia Maria , Negrón-Mendoza Alicia , Ramos-Bernal Sergio 
Published: October 2008

AbstractThe aim of this work is to study the chemistry of the irradiation of frozen solutions of HCN. This compound has been detected in comets and other icy bodies. The CN group might have made its first appearance in the early stages of chemical evolution. Therefore, is behavior under irradiation at low temperature is relevant for chemical evolution studies and icy bodies.
Formation of amino acid precursors with large molecular weight in dense clouds and their relevance to origins of bio-homochirality
Authors: Kobayashi Kensei , Kaneko Takeo , Takano Yoshinori , Takahashi Jun-ichi 
Published: October 2008

AbstractA wide variety of organic compounds have been found in carbonaceous chondrites and comets, which suggests that extraterrestrial organic compounds could have been an important source of the first terrestrial biosphere. In the Greenberg model, these organic compounds in the small bodies were originally formed in interstellar dusts (ISD) in dense clouds by the action of cosmic rays and ultraviolet light. We irradiated a frozen mixture of methanol, ammonia and water with high-energy heavy ions from an accelerator (“HIMAC” in NIRS, Japan) to simulate the action of cosmic rays in dense clouds. Racemic mixtures of amino acids were detected after hydrolysis of the irradiation products. A mixture of carbon monoxide, ammonia and water also gave such complex amino acid precursors with large molecular weights. When such amino acid precursors were irradiated with circular polarized UV light from a synchrotron, enantiomeric excesses were detected. The yield of amino acids was not largely changed between, before, and after CPL-irradiation. The present results suggest that the seed of homochirality of terrestrial amino acids were originally formed in interstellar space.
Guanine synthesis from interstellar organic molecules as an example of prebiotical chemistry
Authors: Medellin Adriana Patricia Lozano 
Published: October 2008

AbstractThe idea that some nitrogen bases, such as adenine and guanine, are easily formed and can be found in interstellar space is should not be rejected. In fact, they have been found in the soluble fraction of some ancient meteors. It is possible that the “seed” of life had its origin in space, and thanks to Earth conditions, a synergistic interaction ocurred and allowed life to spring forth on our planet.
A comparison of different heart rate deflection methods to predict the anaerobic threshold
Authors: Carey Daniel G. , Pliego German J. , Raymond Robert L. 
Published: October 2008

AbstractThere is perhaps no greater controversy in exercise physiology than the validity, or lack thereof, of the heart rate breakpoint theory in general, and the Conconi test in particular, in assessing the anaerobic threshold. Three heart rate breakpoint methods have been proposed as methods of detecting the anaerobic threshold have appeared in the literature: (1) a breakpoint in linearity of the heart rate–work rate relationship (heart rate breakpoint); (2) a log function curve of the heart rate–work rate relationship (log function); and (3) a combination of linear regression and logarithmic function of the heart rate–work rate relationship (log‐linear). The main aim of this study was to assess the validity of these methods compared with that of gas analysis assessment of the anaerobic threshold. This was a descriptive study of 115 endurance athletes undergoing simultaneous gas analysis and heart rate determination during incremental exercise to exhaustion. The participants were 115 competitive cyclists and/or triathletes (71 males: mean age 38.5 years, s=6.2; 44 females: mean age 37.8 years, s=5.1). Incremental exercise testing to exhaustion was performed on an electrically braked cycle ergometer, commencing at 25 W and increasing by 25 W · min−1 to volitional fatigue. Heart rate was recorded each minute and at exhaustion. Gas analysis was performed using breath‐by‐breath analysis with 10‐s averaging. The anaerobic threshold based on ventilatory parameters was used as the criterion test. Compared with the criterion threshold, no significant differences were observed for the heart rate breakpoint (t=1.12, P=0.268) or log function (t=0.0, P=0.998) methods. However, the log‐linear method (t=2.25, P=0.026) significantly overestimated the anaerobic threshold. Although two of the three heart rate methods were validated in this study, the relatively large total errors for these methods (13.7 beats · min−1 for heart rate breakpoint, 12.5 beats · min−1 for log function, and 14.3 beats · min−1 for log‐linear) indicate that they would have little practical value.
An elite endurance athlete's recovery from underperformance aided by a multidisciplinary sport science support team
Authors: Gustafsson Henrik , Holmberg Hans‐Christer , Hassmén Peter 
Published: October 2008

AbstractOverload training resulting in an overreached state is common in elite sports, and if undetected can develop into an overtraining syndrome. This risk is accentuated by the lack of reliable measures of overreaching. Coaches and scientists therefore have to use a combination of tests in the monitoring process. This article presents a case study of the recovery from underperformance of a young elite endurance athlete and the work of a multidisciplinary sport science support team. When it was determined that the athlete's performance had deteriorated, and that this was due solely to the stress of training, training load was radically reduced for a period of 14 days. A combination of physiological, biochemical, and psychological measurements were then used to monitor the recovery process. The purpose of this article is to describe how coaches and sport science teams can help in monitoring training and recovery in practical settings, allowing detection of the early signs of overreaching before a more serious overtraining syndrome develops.
Psychomotor speed is related to perceived performance in rowers
Authors: Nederhof Esther , Visscher Chris , Lemmink Koen 
Published: October 2008

AbstractThe goal of the present study was to determine if psychomotor speed is related to perceived performance. It was hypothesized that lower perceived performance was related to longer reaction times. A total of 85 measurements were taken in 26 varsity rowers (mean age 21.3 years, s=1.6) on five occasions over the course of the season. Perceived performance was measured with the “Reduced Sense of Accomplishment” scale of the Athlete Burnout Questionnaire. Reaction times were measured with the finger pre‐cueing task and with the action and reaction modes of the determination test. The complex structured data were analysed with multi‐level modelling. Random intercept linear models showed that perceived performance was not related to reaction times on the finger pre‐cueing task. Perceived performance significantly predicted reaction times on the action and reaction modes of the determination test. In rowers who were not selected for the team after completing two measurement sessions, this relationship did not exist in the action mode; deselection was a moderator. Thus, a significant relationship between reaction times on the determination test and perceived performance was observed. It was concluded that the determination test could be a useful tool to monitor rowers’ responses to training, although several issues should be resolved before it can be used in practice.
The effect on heart rate variability of acclimatization to a humid, hot environment after a transition across five time zones in elite junior rowers
Authors: Dranitsin Oleg V. 
Published: October 2008

AbstractThe aim of this study was to examine the simultaneous effect on heart rate variability (HRV) of acclimatization to a hot, humid environment and a transition of five time zones in elite junior rowers. Thirteen rowers (12 males and 1 female) participated in the study. Each rower was monitored during training camps in temperate and in humid, hot conditions before and during the Junior Rowing World Championship. All participants recorded the lengths of high‐intensity training sessions, and R‐R (the time between the R peaks of consecutive QRS complexes) intervals were measured every morning after awakening. Compared with baseline values taken during training before the transition to the new time zone and climate, HRV indices during first 3 days of acclimatization remained unchanged. On the fourth and fifth days of acclimatization, significant decreases in measures of heart rate variability in the standing position were observed. Beginning from the sixth day of acclimatization and for all subsequent days, the HRV indices, while standing, returned to baseline values and were not significantly different from baseline. Despite this, there were no significant changes in HRV measures in a supine position until the eighth day of acclimatization. R‐R intervals decreased and mean heart rate increased significantly (P<0.001) during days 8–10 of acclimatization. In conclusion, major physiological adaptation of HRV indices in the standing position during acclimatization to a humid, hot environment, with a transition across five time zones, occurs within the first 5 days in elite athletes before returning to baseline. Indices of heart rate variability in the supine position correlate with the length of high‐intensity training sessions on the previous day.
Science and the Gaelic sports: Gaelic football and hurling
Authors: Reilly Thomas , Collins Kieran 
Published: October 2008

AbstractThe two major sports indigenous to Ireland are Gaelic football and hurling. Both are 15‐a‐side field games played on a pitch 40% longer than a soccer field. They are firmly linked to a nationalist tradition and have by far the highest participation rates in sports in the country. Both games make multiple demands on participants due to their free‐flowing nature and quick movement of play from end to end of the pitch. Hurling calls for hand–eye coordination and skilled use of the hurling stick in hitting and blocking the ball. Fitness characteristics mirror game demands. Participants at elite level in both games display high aerobic power, the footballers tending to be stronger in the upper body and better in vertical jumping. Gaelic footballers in particular match the fitness characteristics of professional soccer players, except for sprinting speed. Less attention has been paid to female participants, especially in camogie, the female version of hurling. Despite their amateur status, and due to the popularity of the sports and the training regimens adopted by players, the games have garnered sports science support systems for elite performers. Support personnel benefit from a generic knowledge base as well as a burgeoning research agenda targeted at the Gaelic games.
Darrieussecq's Mind
Authors: Kemp Simon 
Published: October 2008

Abstract

From
Naissance des fantômes
onwards, Marie Darrieussecq's representation of the self draws heavily on the materialist mind/brain model of cognitive science. Her fiction makes use of the discipline's discourse with and against the grain, creating micro-narratives of the mind's surface level and present moment which contrast sharply with more familiar psychoanalytic perspectives. Narrative form in Darrieussecq, I argue, can be characterized as a stream-of-consciousness, which, while failing to conform to the literary model set by Dujardin and Joyce, is in fact closer to the original psychological conception of the term. The article concludes by examining Darrieussecq's model of the mind in the context of France's current ‘guerre des psys’ between cognitive science and psychoanalysis.
The Judgement of Experience: Reading and Seeing in Diderot's
Lettre sur les aveugles
Authors: Tunstall Kate E. 
Published: October 2008

Abstract

In addition to the usual question underlying empiricist epistemology, namely how we are to judge our sensory experience, Diderot raises the question as to how we are to judge our reading experience, explicitly asking ‘Madame’, the reader, to come to a view as to whether his presentation of the blind man of Puiseaux as a real person is persuasive or not. This essay, building on an earlier article published in
French Studies Bulletin
(2006) which provided original evidence as to the historical reality of the blind man, revisits the question as to his imaginary nature by arguing for the intertextual presence of Montaigne's description of ‘un gentil-homme de bonne maison, aveugle nay’ in the ‘Apologie de Raimond Sebond’. The presence of this intertext, which has not been identified as such before, suggests that in order accurately to judge his or her reading experience the reader requires knowledge of the
Lettre
's literary and philosophical context, a view which is echoed in a different form in Diderot's discussion of Molyneux's Question. In Diderot's view, the woman who sees for the first time will be unable to judge her sensory experience and unable therefore to answer Molyneux's Question, if she does not have knowledge of the question's metaphysical and mathematical background. Where other readers have recently argued that the
Lettre
emphasizes the importance of language in understanding experience, this essay thus argues that the
Lettre
also makes a case for the importance of a literary and philosophical education in our understanding and judgement of experience, be it visual or textual.
Opposites and Identities: Maurice Scève's
Délie
and Charles de Bovelles's
Ars oppositorum
Authors: Banks Kathryn 
Published: October 2008

Abstract

In early sixteenth-century France, uses and conceptions of opposition were varied and shifting. This article analyses some complex and apparently paradoxical notions of opposites and identities found in two very different texts, Charles de Bovelles's
Ars oppositorum
(1511) and Maurice Scève's
Délie
(1544), examples of Latin prose philosophy and vernacular love lyric respectively. I argue that Scève's poetry, like Bovelles's theory, reflects profoundly upon opposition, difference and identity. In particular, I focus in the
Délie
upon relations of opposition and similarity between ‘microcosm’ and ‘macrocosm’, evoked through the poet's use of the ‘jealous sun’ topos. Bovelles explores models of opposition drawn from contrasting generic contexts, including Aristotelian logic and Cusa's mystical theology. However, both the
Délie
and the
Ars
diverge in striking ways from strict categorizations of difference and identity (as typified by traditional dialectic). Both think through the relationships between antithetical modes of difference and other kinds, attempting to imagine even the co-existence of difference and identity. Both also present ways in which one relation of difference inflects another, and thus offer particularly complex accounts of dynamic interactions between opposites.