bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of apparent ileal digestibility of amino acids and nitrogen in cottonseed and soyabean meals fed to pigs determined using ileal dissection under halothane anaesthesia or following carbon dioxide-stunning
Authors: Prawirodigdo S. , Gannon N. J. , van Barneveld R. J. , Kerton D. J. , Leury B. J. , Dunshea F. R.
Published: December 2012

Two experiments were conducted to determine apparent ileal digestibility of amino acids (AIDAA) and nitrogen (AIDN) in cottonseed meal (CSM) and soyabean meal (SBM) fed to growing pigs. In the first experiment, twenty-four male pigs (37·3 (SE 2·7) kg) were individually penned and randomized to either CSM or SBM diets. The diets contained 40% of the protein meal (either CSM or SBM) in a wheat starch-sucrose (1:1, w/w) base containing vitamins and minerals, and Cr2O3as an indigestible marker. Pigs were acclimated to the experimental diets over a 3d period and on day 4 through to day 14 were offered 1800g/d of the diet. Diets were offered in three meals/d from day 4 to day 11 and in eight meals/d from day 12 to day 13. After the eighth hourly-meal on day 14, twelve pigs were anaesthetized with halothane while the remaining twelve pigs were CO2-stunned and processed using commercial slaughter procedures. Ileal digesta were collected from a 1500 mm portion of the terminal ileum of each pig and subsequently analysed for amino acids, N, organic matter and Cr. Results indicated that AIDAA of CSM and SBM were lower when digesta were collected following CO2-stunning than when digesta were obtained under halothane anaesthesia. Consistently, AIDN in CSM (0·51v.0·56) and SBM (0·55v.0-71) were lower (P<0·05) in CO2-stunned pigs than in halothane-anaesthetized pigs. Furthermore, when digesta collection was conducted under halothane anaesthesia, AIDN of CSM was lower (P< 0·001) than that of SBM. In the second experiment, six male pigs (45 (SE 2·6) kg) were fitted with T-piece cannulas implanted in the terminal ileum, housed individually in metabolism cages, and randomly allocated to either CSM or SBM diets in a single reversal arrangement. Ileal digesta were collected for AIDAA and AIDN determination. Although statistical comparisons could not be made between the two experiments, the AIDAA and AIDN data obtained via cannulated pigs were similar to those values obtained using the halothane-anaesthesia method. Overall, the CO2-stunning method is not recommended for studies of amino acid or nitrogen ileal digestibilities, but may be useful for the study of other dietary constituents.
The ‘Mini Nutritional Assessment’ (MNA) and the ‘Determine Your Nutritional Health’ Checklist (NSI Checklist) as predictors of morbidity and mortality in an elderly Danish population
Authors: Beck Anne Marie , Ovesen L. , Osler M.
Published: December 2012

The purpose of the present study was to evaluate the capacity of the‘Determine Your Nutritional Health’ Checklist (NSI Checklist) and the ‘Mini Nutritional Assessment’ (MNA) methods to predict nutrition-related health problems. Data were from the Danish part of the ‘Survey in Europe of Nutrition in the Elderly, a Concerted Action’ (SENECA) baseline survey from 1988, and the follow-up study from 1993. Based on the baseline survey thirty-nine (19.3 %) of the subjects were classified at high nutritional risk, 103 (51 %) were considered at moderate nutritional risk and sixty (29.7 %) were within the ‘good’ range according to the criteria in the NSI Checklist. With the MNA, 171 subjects were classified according to their nutritional risk into a well-nourished group, comprising 78.4 %, and a group who were at risk of undernutrition, comprising 21·6 % at baseline. A total of 115 subjects participated in the follow-up study. The mortality rate and the prevalence of various morbidity indicators were compared between the different risk groups. The analysis showed that subjects with a high MNA score (≥ 24) had significantly lower mortality (rate ratio estimate: 0.35; 95 % Cl 0.18, 0.66) compared with subjects with a low MNA score (≤ 23.5). In contrast, the NSI Checklist score was not a significant predictor of mortality (rate ratio estimate: 1.45; 95 % Cl 0.78, 2.71). The sixteen Danes judged to be at high nutritional risk by the NSI Checklist in 1988, had more acute diseases (P < 0.001) than the rest of the participants, between 1988 and 1993. No significant differences were found in the participation rates, hospitalization rates, physician visits, need of help or weight loss between the groups. The thirteen Danes judged to be at risk of undernutrition in 1988 by the MNA, had a lower participation rate (P < 0.01) and higher occurrence of acute disease (P < 0.05), need of help (P < 0.05), and weight loss (P < 0.001) than the well-nourished group, between 1988 and 1993. No significant differences were found in hospitalization rates and physician visits between the two groups. In conclusion, the results indicate that modified versions of the NSI Checklist and the MNA are capable of identifying a group of 70–75-year-old subjects with increased risk of certain nutrition-related health problems. Further, an MNA score ≤ 23.5 predicts mortality in a Danish population.
La non-participation politique des jeunes : Une étude des barrières temporaires et permanentes de l'engagement
Authors: Mahéo Valérie-Anne , Dejaeghere Yves , Stolle Dietlind
Published: December 2012

Résumé.Avec une méthodologie double, nous portons notre attention sur un groupe très peu étudié : les jeunes non-engagés. Grâce à des entrevues, nous distinguons quatre types de non-engagés: les critiques, ceux qui manquent de ressources politiques, les occupés, et ceux en attente de mobilisation. Lescritiquesne représentent qu'une minorité des non-engagés, alors que les jeunes manquant de ressources sont plus nombreux. Cette étude démontre qu'une grande proportion de jeunes présente un potentiel d'engagement futur et que c'est principalement des barrières temporaires qui réduisent leur niveau d'engagement. L'analyse quantitative dévoile des variations d'attitudes, de profils démographiques et de volontés d'engagement entre types de non-engagés. Les non-engagés ne sont donc pas un groupe homogène.

Abstract.With a two-pronged methodology, this article takes a closer look at an understudied group: the disengaged youth. Using interviews, we discern four different types within this disengaged group: the criticals, those lacking political resources, the busy and those waiting for mobilization. The ‘criticals’ constitute only a minority of the disengaged group, while the young people who lack political resources are more common. Most importantly, a great proportion of young people show a certain potential for engagement. The quantitative analysis reveals that these types resemble distinct attitudinal and demographic profiles, and differ in their future willingness to participate. Thus the non-engaged are not a monolithic group.
The Genocide Question and Indian Residential Schools in Canada
Authors: MacDonald David B. , Hudson Graham
Published: December 2012

Abstract. The Truth and Reconciliation Commission has been investigating the array of crimes committed in Canada's Indian Residential Schools. Genocide is being invoked with increasing regularity to describe the crimes inflicted within the IRS system, the intent behind those crimes, and the legacies that have flowed from them. We ask the following questions. Did Canada commit genocide against Aboriginal peoples by attempting to forcibly assimilate them in residential schools? How does the UN Genocide Convention help interpret genocide claims? If not genocide, what other descriptors are more appropriate? Our position might be described as “fence sitting”: whether genocide was committed cannot be definitively settled at this time. This has to do with polyvalent interpretations of the term, coupled with the growing body of evidence the TRC is building up. We favour using the term cultural genocide as a “ground floor” and a means to legally and morally interpret the IRS system.

Résumé. La Commission de vérité et réconciliation a enquêté sur la matrice de crimes commis dans les pensionnats indiens au Canada. Le mot génocide est invoqué avec une régularité croissante pour décrire les crimes infligés au sein du système des pensionnats, l'intention derrière ces crimes, et l'héritage qui s'en est ensuivie. Nous posons les questions suivantes: le Canada a-t-il commis le génocide contre les élèves Aborigènes en essayant de les assimiler de force dans des pensionnats indiens? Comment la Convention des Nations Unies sur la prévention de génocide peut-elle aider interprétations des revendications de génocide ? Si ce pas de génocide, quel autre descripteur est plus approprié ? Notre position pourrait être décrite comme « séance de clôture »: la question de génocide ne peut être réglée définitivement en ce moment. Cela concerne les interprétations polyvalentes du terme, couplé avec le corps grandissant d'évidence que le CVR accumule. Nous préférons le terme génocide culturel comme « un rez-de-chaussée » et comme un moyen de légalement et moralement interpréter le système IRS.
Was Theocritus A Botanist?
Authors: Lindsell Alice
Published: December 2012

Theocritus sings of eighty-seven different trees, shrubs, flowers, grasses, and ferns. Practically all the references are in the Pastoral Idylls: that is to say, that in the small compass of about 1,200 lines he mentions nearly twice as many plants as Homer does in the whole Iliad and Odyssey. Many of these plants are mentioned several times, and some many times, so the number is impressively great, and implies a great interest: an interest not shown by any other Greek poet. The selection, too, is unprecedented. The Comic Poets may write of things to eat (kitchen-garden produce); the Tragic and Lyric poets, of ceremonial adjuncts; garlands for gods, athletes, feasters (nursery-garden produce). Theocritus' plants are none of these: they are the plants of the mountains, foot-hills, meadows, and shores of the place in which he lived:

αίγίπυρος καί κνύЗα καί εύώλης μελίτεια.

He Writes of plants for their own sakes, and it is this that makes his attitude modern and interesting. Fourteen hundred years before him Minoan painters looked at plants with his eyes: except for them he is unique in Greek history.
Ovid's ‘Lucretia’
Authors: Lee A. G.
Published: December 2012

Every country has its heroes, legendary or historical, who are remembered for some noble action that has caught the popular imagination and made their names immortal. Among the Romans, just as Fabricius was the type of incorruptibility, Decius Mus of devotion to country, Regulus of faith to the pledged word, so the name of Lucretia was proverbial for chastity. The story of her suicide after she had been violated by Sextus Tarquin is recounted by the historians Livy, Dionysius, and Diodorus, and alluded to by many Roman poets and prose-writers. But apart from such allusions, it is curious that of all the Roman poets whose works have come down to us none save Ovid has treated her story at any length; moreover, there is apparently no representation of her among the extant remains of Roman art. To painters and poets of later times, however, she made a strong appeal. In the Fitzwilliam Museum at Cambridge, for example, there is the famous painting by Titian; and in our own literature Chaucer sang the praise of ‘the verray wyf, the verray trewe Lucresse’ in his Legend of Good Women, Gower included her in the seventh book of his Confessio Amantis, Shakespeare in his youth composed that highly coloured arabesque The Rape of Lucrece, Thomas Heywood turned the story into a tragic drama, and most recently Benjamin Britten has made it the subject of an opera.

That Ovid found in Lucretia an attractive figure is evident from the detailed manner in which he treats her story in the second book of his Fasti.
On Misunderstanding the Oedipus Rex
Authors: Dodds E. R.
Published: December 2012

On the last occasion when I had the misfortune to examine in Honour Moderations at Oxford I set a question on the Oedipus Rex, which was among the books prescribed for general reading. My question was ‘In what sense, if in any, does the Oedipus Rex attempt to justify the ways of God to man?’ It was an optional question; there were plenty of alternatives. But the candidates evidently considered it a gift: nearly all of them attempted it. When I came to sort out the answers I found that they fell into three groups.
Political Theology and Secularization Theory in Germany, 1918–1939: Emanuel Hirsch as a Phenomenon of His Time
Authors: Stroup John
Published: December 2012

According to Goethe, “writing history is a way of getting the past off your back.” In the twentieth century, Protestant theology has a heavy burden on its back—the readiness of some of its most distinguished representatives to embrace totalitarian regimes, notably Adolf Hitler's “ThirdReich.” In this matter the historian's task is not to jettison but to ensure that the burden on Protestants is not too lightly cast aside—an easy temptation if we imagine that the theologians who turned to Hitler did so with the express desire of embracing a monster. On the contrary: they did so believing their choice was ethically correct. How could this come to pass in the homeland of the Reformation?
Fishermen Herders: Subsistence, Survival and Cultural Change in Northern Kenya
Authors: Sobania Neal
Published: December 2012

This article examines the unique role played by fishing, hunting and gathering groups in the survival strategy of the pastoralist societies in whose midst they live. During periods of extreme adversity, these groups acted as a refuge for destitute herdsmen and their households by absorbing population in periods of hardship and releasing individuals back into pastoralism when conditions once again allowed the accumulation of stock. Extensive quotations from the historical traditions of the peoples of the Lake Turkana region of northern Kenya are used to detail the recent history of two such fishing communities, the Elmolo and the Dies, the latter being a fishing group within Dasenech society. The epizootics that decimated the cattle herds of East Africa at the end of the nineteenth century are background for examining the interactions of the Elmolo and Dies with their pastoralist neighbours, the Samburu and Rendille, and the cultural changes initiated during this period. The subsequent changes inaugurated by the imposition of colonial rule are documented and the Elmolo are shown to be a ‘dying tribe’ in the sense that the traditional cultural features of their society are giving way to a more pastoral existence based on that of their herding neighbours.
The critical condition of hutias in Cuba
Authors: Alvarez Vicente Berovides , González Antonio Comas
Published: December 2012

Cuba is home for 10 endemic species of hutia. Three of these have become scarce, or extinct, in some parts of their historical range, but remain sufficiently abundant elsewhere to make their conservation of no immediate concern. Of the other seven species, one is believed to be extinct and the rest are in grave danger. The pressures they face include capture by man, competition with introduced rats and destuction of their habitat. Urgent measures are required if these species are to survive.
Contribution of respiratory pathogens to influenza-like illness consultations
Authors: BOLLAERTS K. , ANTOINE J. , VAN CASTEREN V. , DUCOFFRE G. , HENS N. , QUOILIN S.
Published: December 2012

Influenza-like illnesses (ILIs) are caused by several respiratory pathogens. These pathogens show weak to strong seasonal activity implying seasonality in ILI consultations. In this paper, the contribution of pathogens to seasonality of ILI consultations was statistically modelled. Virological count data were first smoothed using modulation models for seasonal time series. Second, Poisson regression was used regressing ILI consultation counts on the smoothed time series. Using ratios of the estimated regression parameters, relative measures of the underreporting of pathogens were obtained. Influenza viruses A and B, parainfluenza virus and respiratory syncytial virus (RSV) significantly contributed to explain the seasonal variation in ILI consultations. We also found that RSV was the least and influenza virus A is the most underreported pathogen in Belgian laboratory surveillance. The proposed methods and results are helpful in interpreting the data of clinical and laboratory surveillance, which are the essential parts of influenza surveillance.
Calculating and communicating tail association and the risk of extreme loss
Authors: Sweeting Paul , Fotiou Fotis
Published: December 2012

In this paper we examine two aspects of extreme events: their calculation and their communication. In relation to calculation, there are two types of extreme events that are considered.

The first is the extent to which extreme events in two or more variables occur together. This can be gauged by using measures of tail association. Higher levels of tail association are useful for highlighting the extent to which there are concentrations of risk. We investigate the range of approaches used to measure tail association and propose a pragmatic alternative, the coefficient of finite tail dependence.

The second type of extreme event arises from combinations of losses from a series of risks that together result in total losses exceeding a particular level. This is measured using ruin lines or, in higher dimensions, planes and hyperplanes. The probability of ruin and the economic cost of ruin are considered here. In this context, it is important to consider what the term “loss” actually means, and whether it is in relation to a current set of exposures or a potential strategy.

The communication of extreme events is discussed not just in terms of the numbers that can be used, but in terms of the graphical methods that can be used to aggregate information on a range of risk combinations. This involves communicating not just the level of risk but also the importance of the risk considered.
Some analytical methods for converting thermochronometric age to erosion rate
Authors: Willett Sean D. , Brandon Mark T.
Published: December 2012

An analytical method is presented for converting thermochronometric ages to surface erosion or, equivalently, exhumation rate. The method incorporates the two most important thermal processes during cooling by erosion: the dependence of closure temperature on cooling rate and the advection of heat by rock motion toward the Earth's surface. Two thermal models are considered: (1) a steady state model, valid for low erosion rates; and (2) an eroding half‐space model, which has no steady state, but captures the transient increase of geothermal gradient with erosion. In each case, it is assumed that data consist of one or more thermochronometric ages, present‐day surface geothermal gradient, and topographic information including the elevation at which the age was obtained. Analytical solutions are provided to derive the erosion rate from these data either as an explicit expression for the steady case or as a root‐finding problem for the transient case. A graphical method for plotting age against erosion rate and geothermal gradient is presented as a method for solving the root finding problem and for tracking analytical errors in observations of age and surface geothermal gradient. The graphical method is also appropriate for comparing data from different elevations or from different thermochronometric systems. Examples are provided using synthetic data or published data from the literature.
Mapping inflation at Santorini volcano, Greece, using GPS and InSAR
Authors: Papoutsis I. , Papanikolaou X. , Floyd M. , Ji K. H. , Kontoes C. , Paradissis D. , Zacharis V.
Published: December 2012

Recent studies have indicated that for the first time since 1950, intense geophysical activity is occurring at the Santorini volcano. Here, we present and discuss the surface deformation associated with this activity, spanning from January 2011 to February 2012. Analysis of satellite interferometry data was performed using two well‐established techniques, namely, Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS), producing dense line‐of‐sight (LOS) ground deformation maps. The displacement field was compared with GPS observations from 10 continuous sites installed on Santorini. Results show a clear and large inflation signal, up to 150 mm/yr in the LOS direction, with a radial pattern outward from the center of the caldera. We model the deformation inferred from GPS and InSAR using a Mogi source located north of the Nea Kameni island, at a depth between 3.3 km and 6.3 km and with a volume change rate in the range of 12 million m3 to 24 million m3 per year. The latest InSAR and GPS data suggest that the intense geophysical activity has started to diminish since the end of February 2012.
The role of Coulomb stress changes for injection‐induced seismicity: The Basel enhanced geothermal system
Authors: Catalli Flaminia , Meier Men‐Andrin , Wiemer Stefan
Published: December 2012

We estimate Coulomb stress variations (ΔCFS) by considering interactions among 163 earthquakes (ML ≤ 3.4) that occurred during the hydraulic stimulation of the enhanced geothermal system in Basel, Switzerland, in 2006. We observe that overall 75% of event locations are consistent with positive ΔCFS. The performance of the model increases with time and distance from injection, accordingly with the presumed less dominant role of the pore pressure further from the injection well and after shut‐in. We analyze the sensitivity of results to location and focal mechanism uncertainties, the fault‐plane ambiguity, and the friction coefficient. We find that ΔCFS are highly sensitive to location accuracy but robust with regard to uncertainties of the other parameters. Our results suggest that (i) the Coulomb model may complement conventional pore‐pressure triggering models and (ii) implementing it for time‐dependent seismic hazard assessment during fluid injection may improve the forecasting ability but will require highly accurate hypocenter estimates.
Coherent ambient infrasound recorded by the International Monitoring System
Authors: Matoza Robin S. , Landès Matthieu , Le Pichon Alexis , Ceranna Lars , Brown David
Published: December 2012

The ability of the International Monitoring System (IMS) infrasound network to detect atmospheric nuclear explosions and other signals of interest is strongly dependent on station‐specific ambient noise. This ambient noise includes both incoherent wind noise and real coherent infrasonic waves. Previous ambient infrasound noise models have not distinguished between incoherent and coherent components. We present a first attempt at statistically and systematically characterizing coherent infrasound recorded by the IMS. We perform broadband (0.01–5 Hz) array processing with the IMS continuous waveform archive (39 stations from 1 April 2005 to 31 December 2010) using an implementation of the Progressive Multi‐Channel Correlation algorithm in log‐frequency space. From these results, we estimate multi‐year 5th, 50th, and 95th percentiles of the RMS pressure of coherent signals in 15 frequency bands for each station. We compare the resulting coherent infrasound models with raw power spectral density noise models, which inherently include both incoherent and coherent components. Our results indicate that IMS arrays consistently record coherent ambient infrasound across the broad frequency range from 0.01 to 5 Hz when wind noise levels permit. The multi‐year averaging emphasizes continuous signals such as oceanic microbaroms, as well as persistent transient signals such as repetitive volcanic, surf, thunder, or anthropogenic activity. Systematic characterization of coherent infrasound detection is important for quantifying a station's recording environment, signal‐to‐noise ratio as a function of frequency and direction, and overall performance, which all influence the detection probability of specific signals of interest.
The 2002/2003 El Niño: Equatorial waves sequence and their impact on sea surface temperature
Authors: Mosquera‐Vásquez K. , Dewitte B. , Illig S. , Takahashi K. , Garric G.
Published: December 2012

The recent decades have experienced changes in the characteristics of the El Niño phenomenon, with in particular an increased occurrence of so‐called Modoki or Central Pacific El Niños. Here the 2002/2003 El Niño, characterized as a Central Pacific El Niño, is studied from an Ocean General Circulation Model simulation. The focus is on the sequence of equatorial waves and their impact on zonal and vertical advection. The wave amplitude according to the most energetic baroclinic modes are first estimated, which allows inferring the sequence of the intraseasonal equatorial Kelvin (IKW) and Rossby (IRW) waves. It is shown that energetic downwelling IKWs, forced in the western‐central Pacific, crossed the equatorial Pacific. Reflections of IKWs into IRWs onto the zonally varying thermocline and eastern boundary are also observed. A simplified heat budget of the surface layer is then carried out to infer the dominant processes at work during the evolution of this event focusing on the wave‐induced advection terms. The results indicate that the warming phase (April–November 2002) is mainly controlled by zonal advection of mean temperature (accounted for by IKWs and locally wind‐driven current) and by vertical advection in the eastern Pacific. The cooling phase (December 2002 to April 2003) is dominated by a reduction in solar radiation and the IRW‐induced zonal advection of mean temperature respectively in the central and eastern equatorial Pacific. The recharge‐discharge process is also showed to be at work with the recharge (discharge) process operating mainly through the second (first) baroclinic mode.
A decade of energy and mass balance investigations on the glacier Kongsvegen, Svalbard
Authors: Karner F. , Obleitner F. , Krismer T. , Kohler J. , Greuell W.
Published: December 2012

Kongsvegen is an Arctic glacier located in northwest Spitzbergen. We use meteorological observations made near the average equilibrium line of Kongsvegen during the decade 2001 to 2010 to drive a glacier energy and mass balance model. Average daily and seasonal cycles are analyzed over the course of a full decade, as well as the interannual variations of the meteorological parameters and of the mass and energy balance components. The calculated average of net radiation is close to zero and the sensible heat flux is the most important and continuous source of energy at the surface. The latent heat flux is a weak source of energy as well. The resultant flux constellation yields a surplus of energy accumulating throughout the decade (9.5 W m–2) and fosters a negative specific surface mass balance throughout the investigated decade (–1.8 m w. eq.). The most significant mass loss occurred during the middle of the decade (2004 until 2006), with positive surface mass balances observed afterward when significant amounts of superimposed ice were formed. This development is well correlated to the total surface mass balance of the glacier. Application of monthly temperature and precipitation perturbations corroborates earlier studies indicating a high sensitivity of the mass balance to energy fluxes depending on temperature conditions during summer.
A decomposition and multistage optimization approach applied to the optimization of water distribution systems with multiple supply sources
Authors: Zheng Feifei , Simpson Angus R. , Zecchin Aaron C.
Published: December 2012

Key Points

Multi‐stage optimization method has been developed and demonstrated

Optimal source partitioning approach is effective for water network optimization

Two real‐world case studies verify the utility of the new optimization method
Very high potassium (VHK) basalt: Complications in mare basalt petrogenesis
Authors: Shervais John W. , Taylor Lawrence A. , Laul J. C. , Shih C.‐Y. , Nyquist L. E.
Published: December 2012

Apollo 14 VHK (Very High Potassium) basalt is a newly discovered variety of low‐Ti, high‐Al mare basalt characterized by unusually high concentrations of K, Rb, and Ba, and high ratios of these elements to other incompatible elements that exceed normal lunar values. Potassium‐feldspar and K, Si‐rich glass are ubiquitous and widespread components of these basalts. Other phases include magnesian olivine (Fo 60–73), Fe‐rich olivine (Fo 31–50), pigeonite, plagioclase (An 79–95), ilmenite, Cr‐ulvő‐spinel, Fe‐metal, and troilite. VHK basalts have low initial 87Sr/86Sr ratios, with Rb/Sr ratios estimated to be ∼15× higher than their source. This Rb/Sr fractionation occurred at their time of formation, 3.75 aeons. Hypotheses involving volatile/nonvolatile fractionations or long‐term enrichment of the source regions in K are inconsistent with the high Ba/La ratios and low initial 87Sr/86Sr ratios of VHK basalt. The most plausible origin for these rocks is partial assimilation of lunar granite by a normal low‐Ti, high‐Al mare basalt. Assimilation occurs by diffusion‐controlled exchange of alkalis and Ba between two melts. Trace element compositions of the granitic melt are controlled in part by refractory accessory phases in the granite. Significant geochemical interaction between the lunar crust and mare basalts is implied.
An apatite‐rich, ferroan, mafic lithology from lunar meteorite ALHA81005
Authors: Goodrich Cyrena Anne , Taylor G. Jeffrey , Keil Klaus
Published: December 2012

Lunar meteorite ALHA81005 contains a clast of ferroan anorthositic troctolite with (in vol %) 59% plagioclase (avg. An 95.4), 27% olivine (avg. Fo 52.2), 11% clinopyroxene (mg 50‐70, Wo 11‐34), and 3% chlorapatite. This clast is probably pristine and is unique among lunar samples. Its texture is igneous, but is unusual in that pyroxene and apatite, which probably cocrystallized, have been brecciated and apparently resorbed, and olivine has precipitated around them. We discuss four possible explanations for this texture: (1) a sudden decrease in pressure occurred, causing liquidus pyroxene to become unstable relative to olivine; (2) the bulk composition of the magma was sufficiently FeO‐rich that pyroxene crystallized before olivine; (3) a P2O5‐rich (2.5‐3.0 wt %), quartz‐normative, basaltic magma that crystallized pyroxene, plagioclase, and phosphates was mixed with an olivine‐saturated magma that had a lower P2O5 content; (4) an olivine‐saturated magma invaded a wall rock assemblage of pyroxene, plagioclase, and apatite. The first two models require only one magma and are attractive because the average compositions of pyroxene, olivine, and plagioclase indicate that they crystallized from liquids with similar mg. The first model cannot be assessed without knowing the bulk composition of the original magma and the initial pressure. The second model cannot account for the brecciation and resorption of the pyroxene and apatite. A model involving either magma‐mixing or wall rock‐magma reaction seems most likely. The high P content and apatite/whitlockite ratio indicate that the parent magma(s) had an unusually high volatile content for a lunar magma. REE in whitlockite are 40‐80 times KREEP abundances. The parent magma(s) must have had very high abundances of REE and La/Sm less than that of KREEP. The clast is also unusually mafic (only 59% plagioclase) for pristine ferroan rocks. Ferroan mafic lithologies appear to be an important component of ALHA81005. The apatite‐rich clast presents several petrologic and geochemical paradoxes, which suggests that complex processes were involved in its formation.
Noble component organization in Apollo 14 Breccia 14318: 129I and 244Pu regolith chronology
Authors: Smith Monty R. , Swindle T. D. , Caffee M. W. , Hohenberg C. M. , Hudson G. B. , Laul J. C. , Simon S. B. , Papike J. J.
Published: December 2012

Noble gas, petrological, and chemical studies made on grain‐size separates from lunar regolith breccia 14318 demonstrate that the noble gases are organized into two functional components, volume‐correlated and surface‐correlated. As in regolith breccia 14301, volume‐correlated xenon in 14318 is primarily spallation‐derived and the surface‐correlated component contains not only solar wind xenon but also significant amounts of “parentless” xenon from the fission of now extinct 244Pu and the decay of now extinct 229I (“parentless” means the daughter products were incorporated onto grain surfaces following decay of the parent nuclide elsewhere). The ratio of 129Xe/136Xe in the total surface‐correlated parentless component, as identified in grain‐size analysis, is substantially higher than in the least tightly bound parentless component identified in stepwise heating analyses, confirming the trend seen in 14301. If the order of release of gases in stepwise heating is related to the order of incorporation in the simplest way (first in, last out), incorporation of these grain‐surface components was probably time‐ordered. The 129Xe/136Xe ratio in each identifiable parentless component would then be characteristic of the xenon available for surface adsorption at the particular time of acquisition. Continuous variations in this ratio further suggest that incorporation of the parentless xenon was closely coupled with production. Such observations provide the basis for a new chronometer from which we conclude that acquisition of parentless xenon was an ongoing process spanning at least 90 m.y., beginning no more than 63 + 34 m.y. after the formation of primitive meteorites and possibly predating xenon acquisition for the earth.
Crustal radiogenic heat production and the selective survival of ancient continental crust
Authors: Morgan Paul
Published: December 2012

If the oldest terrestrial rocks are to be used as a representative sample of the early terrestrial crust, it is important to consider the possibility that they may represent a biased sample. Chemical data indicate that Archean crust is on average depleted in potassium, uranium, and thorium relative to younger crust. Radiogenic isotopes of these elements produce a significant portion of surface heat flow from continents, and low mean heat flow in Archean terrains relative to younger terrains also indicates that these elements are relatively depleted in Archean crust. In stable continental lithosphere the primary variable controlling variations in the geotherm is crustal radiogenic heat production. Qualitative evidence suggests that terrains with low radiogenic heat production, and thus a relatively cool geotherm, are less susceptible to magmatic and tectonic reactivation than terrains with higher heat production and a hotter geotherm. Since crustal radiogenic isotope abundances must have been greater in the past if the isotopes were immobile in stable crust, the relative effect of crustal heat production must have been greater, and thus the range in geotherms must have been greater for the same mantle heat flow. It is suggested that crust with low heat production is less susceptible to orogenic reworking than high heat production crust, and thus there may have been selective stabilization of low heat production (low potassium, uranium, and thorium) crust early in earth history. Either Archean crustal generation was by a mechanism that perhaps fortuitously produced only low heat production crust, or all high heat production crust was reworked by orogenesis during the Archean and did not stabilize in significant volumes until the earliest Proterozoic, perhaps in association with a reduction in mantle temperatures and mean heat flow. If selective crustal reworking did operate during the Archean, surviving Archean terrains may represent a biased sample of the early terrestrial continental crust.
Sulfide and sulfate saturation in hydrous silicate melts
Authors: Carroll M. R. , Rutherford M. J.
Published: December 2012

Hydrothermal experiments have been conducted on a sulfur saturated dacitic melt over a range of pressure, temperature, oxygen fugacity, and melt FeO content in order to examine the effects of these variables on sulfur solubility in fractionated melts. Experiments done under both reducing (GCH, QFM buffers) and oxidizing (MNO, HM buffers) conditions indicate the solubility of sulfur increases with increasing total pressure ( = fluid pressure) over the pressure range 100 to 300 MPa. GCH buffered experiments (1025°C) with 18 to 30 wt % FeO show sulfur solubilities at sulfide saturation ranging from 0.1 to 0.5 wt % S; increasing pressure from 100 to 200 MPa increases sulfur solubility by 500 to 1000 ppm, with the greatest increase observed in more FeO‐rich melts. GCH buffered melts with <5 wt % FeO show no measurable change in sulfur solubility (300±150 ppm S) between 100 and 200 MPa at 1025°C. QFM buffered experiments (1025°C) with 10.0 to 12.5 wt % FeO show sulfur solubility increasing from 600 to 1000 ppm between 100 and 200 MPa. QFM experiments with lower FeO contents (2 to 8 wt %) showed no measurable (±200 ppm S) effect of temperature (912°C to 1025°C) or pressure (100 to 220 MPa) on sulfur solubility. Experiments done under oxidizing conditions of the HM and MNO buffers (1025°C) show sulfur solubilities in melts with 3 to 5 wt % FeO ranging from ∼1400 ppm at 100 MPa to ∼3000 ppm at 300 MPa. More importantly however, the change to more oxidizing conditions is accompanied by a change from sulfide (an FeS‐rich melt) to sulfate (crystalline CaS04) saturated conditions. Stabilization of anhydrite as a magmatic phase (1025°C, 100 to 300 MPa) is also accompanied by a significant increase in sulfur solubility relative to saturation values for more reduced melts with similar FeO contents. The results of this study show that upper crustal oxidation‐reduction and crystal fractionation processes may exert considerable influence on the amount of sulfur contained in magmas erupted at the surface. These results are of basic importance in understanding volatile transport and volcanic degasing processes on planets such as the Earth, Mars, and Venus.
Molybdenum in eucrites: Evidence for a metal core in the eucrite parent body
Authors: Newsom Horton E.
Published: December 2012

Molybdenum concentrations from 15 to 70 ppb in eucrites have been determined with a new method of neutron activation. These values are very low compared to chondrites and are in agreement with the large depletions of other siderophile elements in eucrites. The eucrites have a mean Mo/La ratio of 0.0066, which is a factor of 570 lower than the CI chondritic ratio (3.75). The depletions of siderophiles in eucrites were presumably caused by segregation of metal. Molybdenum, however, is fractionated as an incompatible element, similar to La, among the individual eucrites. The variable concentrations, but roughly constant ratio, of Mo to La indicate that metal was absent during the fractionation that produced the eucrites and imply that core formation occurred before the fractionation. The need for a relatively large degree of partial melting to completely segregate metal argues for a fractional crystallization model for the production of the eucrite magmas. The amount of metal in the Eucrite Parent Body (EPB) required to obtain the observed depletion of the Mo/La ratio depends on the degree of partial melting during metal‐silicate equilibrium. The depletion of Co has a dependence on the degree of partial melting different from Mo and W, and using Co together with Mo and W the metal content and degree of partial melting can be estimated. A metal content of 30% to 50% and metal segregation at approximately 50% partial melting of the silicates is consistent with the data. If the EPB had a ratio of Co to refractory lithophile elements less than CI chondrites, a metal content as low as 20%, with metal segregation at 20% partial melting, is possible. A large metal core in the EPB (Vesta?) may therefore be detectable from a spacecraft.
A model for the origin of basaltic achondrites based on the Yamato 7308 Howardite
Authors: Ikeda Y. , Takeda H.
Published: December 2012

The Y‐7308 howardite comprises a variety of lithic clasts and mineral fragments. The Mg/(Mg+Fe) atomic ratios of the pyroxenes in diogenitic clasts, eucritic clasts, and Fayalite‐Hedenbergite‐Tridymite‐Plagioclase clasts vary continuously from 0.76 to less than 0.30. Olivine fragments in the matrix have a wide range of Mg/(Mg+Fe) ratios from 0.88 to 0.71. This continuum of chemical compositions for olivine and pyroxene is explained by the fractional crystallization of a primary magma. The composition of a liquid produced by removing olivine and pyroxene from the primary magma is almost identical to that of eucrites, and the solidification of this liquid on the surface of a magma ocean might have formed a eucrite crust on the parent body. A source material of carbonaceous or LL chondrite‐like composition may produce the HED (Howardites, Eucrites, Diogenites) magma by partial or batch melting. The volatile components such as alkalis, sulfur oxides, etc. may have been lost, and reduction of FeO and Fe203 components to Fe metals also may have taken place prior to and/or during the formation and crystallization of the HED magma.
Magnetite morphologies in the Essebi and Haripura CM chondrites
Authors: Hyman M. , Ledger E. B. , Rowe M. W.
Published: December 2012

Many of the unusual magnetite morphologies previously observed only in the CI chondrites have been seen in the CM chondrites, Essebi and Haripura. These include: heavily textured spheroids, which are possibly spherulites, found both singly and in groups of up to a dozen and ranging in size from ∼4 to 10 μm in diameter; collections of microcrystals varying from ∼0.3 to 6 μm in diameter; spheres of ∼1 to 6 μm in diameter; layered, nearly circular plates, forming a spheroidal plaquette ∼7.5 μm in diameter; clusters of variable sized nodules, ∼1.5 to 6 μm, with concave features; framboidal magnetite; and finally collections of less distinctive globules.
Trapped Xe components in etched samples of the Murray (C2) and Murchison (C2) carbonaceous chondrites
Authors: Jones C. M. , Lumpkin G. R. , Reynolds J. H.
Published: December 2012

Xe isotopic measurements are described. The samples analyzed were bulk chips of the Murray (C2) and Murchison (C2) carbonaceous chondrites that had been freeze‐thaw disaggregated, etched with H2O2, and then split into colloidal and noncolloidal fractions using methanol. The etching removed a substantial portion of the trapped Xe and increased variations in measured isotopic ratios compared with bulk sample analyses. The Murray samples appeared to contain a binary mixture of U‐Xe and H+L‐Xe. The Murchison data concur with the Murray data for the heavy isotopes, but the structure at the light isotopes is obscured by spallation Xe. There is no evidence in these data for the separability of H‐Xe and L‐Xe. The fact that H2O2 etching removes Xe without prior demineralization supports the view that the carrier of a substantial portion of trapped Xe may reside on grain surfaces.
Venus gravity: A harmonic analysis and geophysical implications
Authors: Mottinger N. A. , Sjogren W. L. , Bills B. G.
Published: December 2012

An improved model of Venusian global gravity has been obtained by fitting a tenth degree and order spherical harmonic series to 78 orbital arcs of Doppler tracking data from Pioneer Venus Orbiter. Maps of the free‐air anomaly and its formal error are presented, as are “geoid” and isostatic anomaly maps. The gravitational variance spectrum of Venus has a form very similar to that observed previously on the earth, moon, and Mars. In contrast to the earth, Venus exhibits a significant positive correlation between topography and gravity. The gravity/topography admittance function is consistent with a global average effective depth of isostatic compensation of 200 ± 40 km. The second‐degree harmonics determine the orientation of the principal inertial axes and thereby reveal two unusual features. First, the axis of greatest inertia departs from the rotation axis by 3°. However, the extremely slow rotation of Venus makes the resulting large amplitude wobble energetically comparable to the 0.3 arc sec Chandler wobble of the earth. Second, the orientation of the axis of least inertia relative to the sub‐earth point at times of particularly close inferior conjunctions is strongly suggestive of a spin‐orbit resonance with earth, albeit not the resonance that has usually been considered in the past.
Gravity field of venus at constant altitude and comparison with Earth
Authors: Bowin Carl , Abers Geoffrey , Shure Loren
Published: December 2012

The acceleration (gravity) anomaly estimates by spacecraft tracking, determined from Doppler residuals, are components of the gravity field directed along the spacecraft‐earth line‐of‐sight (LOS). These data constitute a set of vector components of a planet's gravity field, the specific component depending upon where the earth happened to be at the time of each measurement, and they are at varying altitudes above the planet surface. From this data set we have solved for the gravity field using the method of harmonic splines, which imposes a smoothness criterion to select a gravity model compatible with the LOS data. Maps of geoid and gravity at spacecraft and at constant altitudes are presented for the planet Venus. For Venus, the major geoid and gravity anomalies each coincide spatially with the locations of positive topographic features. These anomalies at 300 km altitude have significantly greater magnitude than anomalies that on earth are coincident with topographic features. Another striking difference is that most of the major geoid anomalies on the earth do not coincide with locations of its largest topographic features, including continents, but are due to deep sources. On Venus, major mass anomalies appear to be restricted principally to the surficial 200 km of the planet. A substantially thicker crust on Venus (70–80 km), compared to the earth's (5–40 km), can explain its greater range of gravity anomaly and the positive correlation of gravity anomaly withtopographic height. Four regions with high gravity to topography response functions are interpreted to be due to crustal loading by recent volcanism perhaps combined with regional elevation of surface topography by thermal expansion from heating at depth.
The geomorphology of Rhea: Implications for geologic history and surface processes
Authors: Moore Jeffrey M. , Horner Vicki M. , Greeley Ronald
Published: December 2012

Analyses of landforms on Rhea are used to define three physiographic provinces (cratered terrain 1 undifferentiated, cratered terrain 1 lineated, cratered terrain 2) for which stratigraphic relationships are derived and examined in relation to major impact basins and tectonic features. The formation of multiringed basins may have caused, or at least controlled, the locations of major resurfacing and mantling events. The diameters of central peaks relative to impact crater diameters are significantly larger than those within craters on the moon and Mercury. Rim segments of polygonal craters have preferential orientations. Both crater and noncrater lineaments show regional orientations that do not fit current global or regional stress models. Superposition relationships of provinces and associated features imply the following postaccretional sequence for the geological evolution of Rhea's surface. Cratered terrain 1 undifferentiated formed first. Then linear troughs and chains of coalescing pits developed extensively on cratered terrain 1 lineated. A resurfacing event emplaced cratered terrain 2, on which small craters, scarps, and ridges formed. Small grooves on cratered terrain 1 undifferentiated are tentatively assigned a young age, based on their susceptibility to impact erosion. This geologic history is generally consistent with theoretical models for Rhea's evolution.