bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective hydrogenation with tris(triphenylphosphine) chlororhodium (I) catalyst: Preparation of octadecenoate isomers
Authors: Emken E. A.
Published: July 2007

Fractionation of products obtained from partial catalytic hydrogenation of methylcis‐9,cis‐12‐octadecadienoate (9c,12c‐18:2) with tris(triphenylphosphine) chlororhodium [RhCl(Ph3P)3] provided a facile method for preparation of a nearly equal molar mixture of methylcis‐9‐ andcis‐12‐octadecenoate (9c‐18∶1 and 12c‐18∶1). Isolation of products was achieved by silver resin and C18 reverse phase liquid chromatography. Catalytic deuteration of 9c,12c‐18∶2 yields a mixture of 9c‐18∶1‐12,13‐d2 and 12c‐18∶1‐9,10‐d2 with an isotopic purity of 85%. Final isolated yield of the mixture of 9c‐ and 12c‐18∶1 products was 30%. Isolation of products from partial hydrogenation of conjugated octadecadienoates (9c,11t‐18∶2 or 10t,12c‐18∶2) provided a convenient method for synthesis of an almost equal molar mixture of methyltrans‐10 andtrans‐11‐octadecenoate (10t‐18∶1 and 11t‐18∶1). Characterization of the reaction products from hydrogenation of 9c,12c‐28∶2 indicates that the 9c‐ and 12c‐18∶1 products are formed by the expected 1,2‐hydride addition. The presence of small amounts of 10t‐ and 11t‐18∶1 and conjugated octadecadienoates was evidence for a secondary isomerization‐1,4‐hydride addition pathway. Isolation and characterization of products from RhCl(Ph3P)3‐catalyzed hydrogenation of 9c,11t‐18∶2 and 10t,12c‐18∶2 indicate that both 1,2‐ and 1,4‐hydride addition to the conjugated diene isomers occurs at about equal rates, but only thecis bond is reduced by the 1,2‐hydride addition pathway and the 1,4‐hydride addition pathway yields only atrans‐18∶1. Because of this unusual selectivity for acis bond conjugated with atrans bond, hydrogenation of both 9c,11t‐18∶2 and 10t,12c‐18∶2 yields the same mixture of t‐18∶1 isomers.
Determination of chlorophyll in ground rapeseed using a modified near infrared reflectance spectrophotometer
Authors: Tkachuk R. , Mellish V. J. , Daun J. K. , Macri L. J.
Published: July 2007

A rapid and accurate method has been developed for the analysis of chlorophyll in ground rapeseed using a modified near infrared filter instrument. Ground rapeseed was scanned with a Cary 17 spectrophotometer, and optimal wavelengths for chlorophyll prediction (674, 696 nm) were selected from the visible wavelength region by multiple linear regression analysis. Six Dickey‐john Instalab 600's were modified to analyze chlorophyll in ground rapeseed by replacing two standard near infrared filters with two filters having central wavelengths of 674 and 696 nm. Calibration equations incorporating data from three wavelengths (674, 696 and 2100 nm) had an average multiple correlation coefficient (R) of 0.980 and standard error of estimate (SEE) of 3.1 ppm. Instrument prediction of chlorophyll agreed well with reference solvent extraction analyses (standard error of prediction, SEP=3.0 ppm). A universal calibration equation developed for the determination of chlorophyll in ground rapeseed was tested with several modified instruments and performed well.
Examining ventral and dorsal prefrontal function in bipolar disorder: A functional magnetic resonance imaging study
Authors: Frangou Sophia , Kington Justin , Raymont Vanessa , Shergill Sukhwinder S.
Published: July 2007

Several lines of research suggest both dorsal and ventral prefrontal cortical dysfunction in bipolar disorder (BD). We used functional magnetic resonance imaging to compare patterns of brain activation in remitted BD patients and controls whilst performing tasks selected for their relative specificity in engaging either the dorsal (n-back sequential-letter working memory task) or ventral (gambling task) PFC. Seven BD patients were selected from participants of the Maudsley Bipolar Disorder Project on the basis of clinical remission, absence of cognitive deficits, and monotherapy with mood stabilisers. Subjects were individually matched by gender, age, and IQ to an equal number of healthy controls. In the n-back task, group differences were only present in response to increasing memory load. Patients did not show the predicted dynamic response in the dorsal PFC, but had increased activation in the parietal cortices. During the gambling task, controls showed significant activation in the ventral and dorsal PFC; this was attenuated in BD patients where increased activation was seen in lateral temporal and polar regions. Our findings suggest that there are trait abnormalities in dorsal and ventral PFC function in BD that may be more pronounced during tasks that rely on ventral–dorsal PFC interaction.
The Struggle between “Religion and Nonreligion”: Jefferson, Backus, and the Dissonance of America's Founding Principles
Authors: OWEN J. JUDD
Published: July 2007

The prevailing view of both the U.S. Supreme Court and liberal theory in America is that liberal principles are neither essentially religious nor essentially secular, but somehow foundationally neutral, or in the words of the Court neutral between “religion and nonreligion.” This essay challenges the cogency of this view through a comparative examination of two strong defenders of religious freedom from the American revolutionary era: Thomas Jefferson and Isaac Backus. Jefferson, the Enlightenment rationalist, and Backus, the Calvinist-Baptist, may initially seem tailor-made for this foundational neutrality, but closer examination reveals that religious freedom for them was not only an extension of their radically opposed views on religion but also an instrument for the promotion of those views throughout society. The ambiguity of America's founding principles is best understood, not through the notion of neutrality, but as the product of a yet unsettled struggle between devout religion and secular Enlightenment.
When Do States Follow the Laws of War?
Authors: MORROW JAMES D.
Published: July 2007

The laws of war seek to regulate conduct during wartime. The record of compliance with these treaties is mixed. I explain compliance as the result of publicly accepted and so legally binding agreements that create incentives for the parties to enforce those agreements through reciprocity. Ratification by a democracy is a signal that it intends to abide by the treaty standard; those that ratify are more likely to comply. Ratification does not effect the behavior of nondemocracies, however. Ratification of the relevant treaty by both warring parties strengthens reciprocity. There is a hierarchy of average compliance across issues which matches the scope for violations by individuals on each issue, with greater scope for such violations corresponding to lower levels of compliance.
Vote Choice in Suburban Elections
Authors: OLIVER J. ERIC , HA SHANG E.
Published: July 2007

Despite the importance of local elections in the United States, political scientists have little knowledge of what shapes vote choice in most municipalities and special districts, particularly in the suburbs where a majority of Americans live. This article develops and tests models of local voting behavior using unique survey data of over 1,400 voters in 30 different suburban communities. Suburban electoral politics are dominated by a nonrepresentative group of “stakeholders,” who are highly informed and interested in local affairs. Because of this, vote choice in suburban elections ends up sharing many characteristics with larger contests (i.e., issue salience, partisanship, and candidate likeability), although their impact varies with the size and diversity of the particular community (e.g., in smaller suburbs, voters are more engaged in local politics, more likely to know candidates personally, and more likely to vote against incumbents). These findings suggest the importance of developing new theories about voting behavior in micro-electoral contexts.
Who Keeps International Commitments and Why? The International Criminal Court and Bilateral Nonsurrender Agreements
Authors: KELLEY JUDITH
Published: July 2007

What do countries do when they have committed to a treaty, but then find that commitment challenged? After the creation of the International Criminal Court, the United States tried to get countries, regardless of whether they were parties to the Court or not, to sign agreements not to surrender Americans to the Court. Why did some states sign and others not? Given United States power and threats of military sanctions, some states did sign. However, such factors tell only part of the story. When refusing to sign, many states emphasized the moral value of the court. Further, states with a high domestic rule of law emphasized the importance of keeping their commitment. This article therefore advances two classic arguments that typically are difficult to substantiate; namely, state preferences are indeed partly normative, and international commitments do not just screen states; they also constrain.
Children recovered from malnutrition exhibit normal insulin production and sensitivity
Authors: Martins Vinicius J. B. , Martins Paula A. , Neves Janaína das , Sawaya Ana L.
Published: July 2007

Protein–energy malnutrition promotes adaptive hormonal changes that result in stunting. A previous study showed that stunted children had increased insulin sensitivity and diminished pancreatic β-cell function. The objectives of the present study were to analyse the glucose, insulin, homeostasis model assessment of insulin sensitivity (HOMA-S) and homeostasis model assessment of pancreatic β-cell function (HOMA-B) levels after nutritional recovery. The recovered group (n 62) consisted of malnourished children after treatment at a nutrition rehabilitation centre. At the beginning of treatment their age was 2·41 (sd 1·28) and 2·31 (sd 1·08) years, weight-for-age Z score − 2·09 (sd 0·94) and − 2·05 (sd 0·55) and height-for-age Z score − 1·85 (sd 1·11) and − 1·56 (sd 0·90), for boys and girls respectively. The control group consisted of well-nourished children without treatment (n 26). After treatment, boys of the recovered group gained 1·29 (sd 1·06) Z scores of height-for-age and 1·14 (sd 0·99) Z scores of weight-for-age, and girls, 1·12 (sd 0·91) and 1·21 (sd 0·74) Z scores respectively. No differences were found between control and recovered groups in insulin levels for boys (P = 0·704) and girls (P = 0·408), HOMA-B for boys (P = 0·451) and girls (P = 0·330), and HOMA-S (P = 0·765) for boys and girls (P = 0·456) respectively. The present study shows that the changes observed previously in glucose metabolism and insulin were reverted in children who received adequate treatment at nutritional rehabilitation centres and showed linear catch-up.
Beyond Law and Order: The Origins of the Jogo do Bicho in Republican Rio de Janeiro
Authors: CHAZKEL AMY
Published: July 2007

At the beginning of Brazil's First Republic (1889–1930), the clandestine lottery called the jogo do bicho or ‘animal game’, which still exists today, gained enormous popularity in Rio de Janeiro, the city of its origin, and soon in the whole of Brazil. Reconstructing the spread and persecution of the jogo do bicho during its first decades reveals the social process of urbanisation evident in the daily, often informal and quasi-legal, interactions between the state and popular commerce in Latin America. The ambivalent official stance and public sentiment that developed toward this lottery suggest that ‘law and order’ concerns in themselves do not explain the criminalisation of vernacular practices.
Rankine–Hugoniot relations for shocks with demagnetized ions
Authors: GEDALIN M. , BALIKHIN M.
Published: July 2007

The width of a quasi-perpendicular collisionless shock front is smaller than the convective ion gyroradius so that ions become demagnetized in the ramp. An approach is proposed for derivation of approximate expressions for the magnetic compression ratio and cross-shock potential from the analysis of the ion motion across the ramp and pressure balance condition, without making assumptions about the ion equation of state. The cross-shock potential and magnetic compression ratio are found as functions of the Mach number for low-Mach-number perpendicular shocks.
Effects of habitat fragmentation on wild mammal infection by Trypanosoma cruzi
Authors: VAZ V. C. , D'ANDREA P. S. , JANSEN A. M.
Published: July 2007

Expansion of human activities frequently results in habitat fragmentation, a phenomenon that has been widely recognized in the last decades as one of the major threats to world's biodiversity. The transformation of a continuous forest into a fragmented area results in a hyper-dynamic landscape with unpredictable consequences to overall ecosystem health. The effect of the fragmentation process on Trypanosoma cruzi infection among small wild mammals was studied in an Atlantic Rain Forest landscape. Comparing continous forest to fragmented habitat, marsupials were less abundant than rodents in the continuous landscape. An overall decrease in small wild mammal richness was observed in the smaller fragments. An anti-T. cruzi seroprevalence of 18% (82/440) was deteced by immunofluorescence assay. Moreover, this seroprevalence was higher in the fragmented habitat than in the continuous forest. According to the collected data, 3 main factors seem to modulate infection by T. cruzi in small wild mammals: (i) habitat fragmentation; (ii) biodiversity loss; (iii) increase of marsupial abundance in mammal communities. Furthermore, an extremely mild controlled infection by T. cruzi was detected since no patent parasitaemia could be detected in fresh blood samples, and no parasites were isolated by haemoculture.
FORGOTTEN OFFERINGS: MESSIAEN'S FIRST ORCHESTRAL WORKS
Authors: Dingle Christopher
Published: July 2007

The prevailing image of Messiaen in the 1930s is of an organist-composer. One of the first things learnt about him is that he was organist at the church of the Trinité in Paris, having been appointed at the spectacularly young age of 22. As the earliest (though not the first) of Messiaen's works to have been published, the short organ piece Le Banquet céleste (1928) is, quite rightly, the focus of close examination for its precocious assurance. The 1930s were punctuated by the substantial organ cycles La Nativité du Seigneur (1935) and Les Corps glorieux (1939), so it is no surprise to find Felix Aprahamian's article for the fifth edition of Grove describing Messiaen as being a ‘French organist and composer”, and later observing that ‘although it was as a composer of organ music that in pre-war years Messiaen's name first attracted attention, he had already composed a quantity of vocal music’. Fifty years later, Paul Griffiths similarly observed that ‘Organ works featured prominently in his output of the next decade [1930s], but so did music about his family’. According to Harry Halbreich, ‘one can say that before 1940, Messiaen was essentially an organist-composer’, while, Malcolm Hayes concludes his chapter on the early orchestral music in The Messiaen Companion by stating that ‘to judge from the idiom of his works written in the 1930s, he had once seemed destined to spend his creative life within the narrow confines of the organ loft’.
What about the neural basis of crystallized intelligence?
Authors: Lee Kun Ho , Choi Yu Yong , Gray Jeremy R.
Published: July 2007

General intelligence is largely based on two distinguishable mental abilities: crystallized intelligence (gC) and fluid reasoning ability (gF). The target article authors' P-FIT model emphasizes a network of regions throughout the brain as the neural basis for fluid reasoning and/or working memory. However, it provides little significant insight into the neural basis of gC, or how or why gC is more stable than gF across the life span.
Can the Parieto-Frontal Integration Theory be extended to account for individual differences in skilled and expert performance in everyday life?
Authors: Roring Roy W. , Nandagopal Kiruthiga , Ericsson K. Anders
Published: July 2007

Performance on abstract unfamiliar tasks used to measure intelligence has not been found to correlate with individual differences in highly skilled and expert performance. Given that cognitive and neural structures and regions mediating performance change as skill increases, the structures highlighted by parieto-frontal integration theory are unlikely to account for individual differences in skilled cognitive achievement in everyday life.
Right answer to the wrong question: A reply to Jung and Haier
Authors: Sternberg Robert J.
Published: July 2007

Jung & Haier (J&H) have done an admirable job of solving the wrong problem. Their article does not show “where in the brain is intelligence,” because intelligence resides not in the brain but, rather, in the interaction of brain and environment. I describe four reasons why the article does not adequately localize intelligence in the brain.
The hipparions (Mammalia, Equidae) of Suffolk, England
Authors: Forsten Ann
Published: July 2007

A study of a sample of hipparion teeth from Pliocene marine fossil deposits in Suffolk revealed two species, belonging to different genera of these three-toed horses. Hipparion sp. (of the H. crassum Group) and Proboscidipparion sp. have different stratigraphic ranges on the European continent. Their stratigraphic origin in the Suffolk deposits is discussed, based on a review of the occurrence of similar forms on the European continent.
The dermal skull roof of Acanthostega gunnari, an early tetrapod from the Late Devonian
Authors: Clack J. A.
Published: July 2007

The dermal skull roof of Acanthostega gunnari Jarvik is described in detail, giving new information on the anatomy, and new reconstructions of the skull in dorsal, lateral and occipital views, as well as sections through the skull at two points. The types of suture are compared with those of temnospondyls and discosauriscids, comparable animals in terms of habit and skull shape. The skull-bones of Acanthostega are much more closely integrated with each other than those of the two later groups. However, regions of relatively less firmly and more firmly sutured regions are comparable in position. This may be connected with having the lateral lines accommodated in tubes in Acanthostega rather than grooves, or some other property of the dermal bone in the later groups that reduced the need for stronger integration. The post-orbital region of the skull (skull table) is the most strongly integrated region, possibly connected with the need for attachment of occipital musculature. The skull table and dentition are the most labile of cranial features among Devonian tetrapods, whereas the snout, cheek, palate and infradentary regions remain conservative. These are for the most part the lateral-line-bearing regions of the skull. The specimens of Acanthostega found at one site on Stensiö Bjerg may form part of a year-group that had perhaps come together for spawning.
The trilobite Family Illaenidae Hawle et Corda, 1847 from the Ordovician of the Prague Basin (Czech Republic)
Authors: Bruthansová Jana
Published: July 2007

This present revision of Bohemian Ordovician illaenid trilobites of the Prague Basin (Czech Republic) follows the recent evaluation of their systematic position. This revision contains redescriptions and illustrations of the type species of several illaenid genera, the most up-to-date references for those genera, and an assessment of their variability and also of the palaeobiogeographic distribution of some illaenid genera. Bohemian illaenids in several cases include the type species of globally distributed taxa, whose distinction has often been uncertain and controversial. The validity of the genera Zbirovia Šnajdr, 1956 and Zdicella Šnajdr, 1956 is discussed and confirmed. The genus Alceste Hawle et Corda, 1847 stays in open nomenclature. In Ectillaenus katzeri katzeri (Barrande, 1856) allometric growth is described and Vysocania Vaněk & Vokáč, 1997 is considered to be a junior synonym of Stenopareia Holm, 1886.
Early acanthodians from the Lower Silurian of Asia
Authors: Karatajute-Talimaa Valentina , Smith Moya Meredith
Published: July 2007

Abundant microvertebrate remains from the Siberian Platform are described as early acanthodians. All are preserved with both excellent morphology and histology. They are assigned to a new order, Tchunacanthida, with two new families, Lenacanthidae and Tchunacanthidae. These comprise two new genera, Lenacanthus and Tchunacanthus with type species L. priscus sp. nov. and T. obruchevisp.nov. The evidence from the morphology and histology is that they are the most ancient acanthodian scales so far found. The total collection of vertebrate material from the Irkutsk amphitheatre is described, together with their geological distribution, geographical range and systematic palaeontology. Head scales, tesserae of three morphotypes, transitional scales and body scales have been found. All comprise morphological sets as determined by comparison of morphology using SEM and of histology using Nomarsky interference optics. Observations of growth were possible from details of concentric lines on the crown and also from incremental layers seen in both horizontal and vertical sections. Starting from the primordial scale, consecutive layers are added, coronally, laterally, and deep in the corium onto the base; these occurred simultaneously in both crown and base. A type of areal-superpositional growth occurred in some body scales but in other scales there was little superpositional growth. It is concluded that Tchunacanthus possessed very solid body armour with tightly joined scales covering a large area of the body, and scale bases deeply set in the corium. Both tissues of the scales, dentine and bone, feature enclosed cells. This character is regarded as primitive within acanthodians, as in derived forms both tissues are acellular. Acanthodian scales are one of many examples of transformation from cellular to acellular tissue in evolution.
A new crustacean from the Early Devonian Rhynie chert, Aberdeenshire, Scotland
Authors: Fayers Stephen R. , Trewin Nigel H.
Published: July 2007

A new crustacean, Castracollis wilsonae is described from a loose block of the Early Devonian Rhynie chert, found in the vicinity of Rhynie, Aberdeenshire, Scotland. It differs markedly from Lepidocaris rhyniensis, Scourfield 1926, the only other crustacean found in the Rhynie chert.

The material comprises complete individuals up to 8 mm long and fragmentary remains. The head is normally damaged and detached from the body, and damage to the anterior of the trunk suggests the specimens are exuviae. The head appears domed with a labrum, robust mandibles, and long biramous antennae. A few specimens exhibit a probable detached cephalo-thoracicshield. The trunk is multi-segmented, comprising similar ring-like somites. The thorax variably comprises up to 26 segments. The anterior 11 segments possess similar long, phyllopodous appendages, the remainder variably possess 10 to 15 phyllopodous appendages with a disposition of one per somite. The abdomen comprises up to 28 apodous segments. The posterior of the body comprises a telson with two furcal rami.

The crustacean is most probably a calmanostracan branchiopod. It occurs associated with Lepidocaris, charophytes, cyanobacteria and coprolites within a ‘clotted’ chert texture, indicating subaqueous deposition, most probably in a temporary freshwater pool in an area of surficial hydrothermal activity.
A marginal marine ichnofauna from the Blaiklock Glacier Group (?Lower Ordovician) of the Shackleton Range, Antarctica
Authors: Weber B. , Braddy S. J.
Published: July 2007

A diverse arthropod-dominated ichnofauna, associated with a poorly preserved crustacean fauna and soft-bodied ?medusoid impressions, is described from the Blaiklock Glacier Group of the north-western Shackleton Range (Coats Land), Antarctica. The ichnofauna consists of Asaphoidichnus, Beaconites, Didymaulichnus, Diplichnites, Gordia, ?Laevicyclus, Merostomichnites, Monomorphichnus, Palaeophycus, Planolites, Rusophycus, Selenichnites, and Taphrhelminthoides (ichnogen nov.). Three new ichnotaxa are recognised: Taphrhelminthoides antarcticus n. ichnogen. et ichnosp. is a bilobate trail, composed of two parallel flat lobes, separated by a median ridge with a characteristic figure-of-eight pattern. Merostomichnites gracilis n. ichnosp. is characterised by its proportions (external:internal width ratio >3) and series of 10 to 12, thin, linear tracks. Selenichnites antarcticus n. ichnosp. is characterised by small elongate horseshoe-shaped marks, the medial portion showing three to five transverse scratch-marks.

The palaeoenvironment is interpreted as extremely shallow marine water, possibly a tide-dominated estuary, based on sedimentological evidence and the composition of the ichnofauna. Radiometric and palaeomagnetic data indicate that this assemblage is Lower Ordovician in age, representing the first autochthonous Ordovician fossiliferous succession to be described from Antarctica. The succession shows several sedimentological and palaeontological similarities with the basal units of the Ordovician Table Mountain Group in South Africa, supporting palaeogeographic models placing the Palaeozoic Blaiklock basin close to the Ordovician Table Mountain basin.
Bembicosoma re-examined: a xiphosuran from the Silurian of the North Esk Inlier, Pentland Hills, Scotland
Authors: Anderson Lyall I. , Moore Rachel A.
Published: July 2007

The Silurian arthropod Bembicosoma pomphicus Laurie, 1899 is re-studied in relation to other Palaeozoic chelicerate taxa. All three known specimens of Bembicosoma originate from the Silurian (late Llandovery) Eurypterid Bed of the Gutterford Burn Flagstones, Reservoir Formation, Pentland Hills, Scotland. Bembicosoma is removed from its previous tentative assignment to Eurypterida and re-assigned to Xiphosura. A morphological reconstruction of this taxon is presented for the first time. This work continues a reappraisal of the systematics of a number of taxa that belong within the synziphosurines, a loose grouping of early Palaeozoic chelicerate arthropods aligned with the Xiphosura (horseshoe crabs), but which have been mistakenly identified as eurypterids in the past. Bembicosoma is significant as it is one of the earliest known synziphosurines.
Summary of a revision of New York State Ordovician eurypterids: implications for eurypterid palaeoecology, diversity and evolution
Authors: Tollerton Victor P.
Published: July 2007

The record of Ordovician Eurypterida from New York State, USA, is shown to be largely false. Twenty-nine species in 17 genera are here recognised as pseudofossils, reducing by more than 75% the total number of named Ordovician eurypterid taxa. Consequently, 10 families now have their first occurrence either later in the Ordovician or in the Early Silurian. The implications for eurypterid palaeoecology, diversity and evolution are not as straightforward as would be expected from such a drastic taxonomic revision. All Ordovician eurypterids are now known to occur in shallow-water, near-shore shales or fine-grained carbonates. Diversity measures indicate that the end-Ordovician extinction event appears to have had less effect on eurypterids than previously known, and their turnover is level in the Ordovician.
Embryophytic sporophytes in the Rhynie and Windyfield cherts
Authors: Edwards Dianne
Published: July 2007

Brief descriptions and comments on relationships are given for the seven embryophytic sporophytes in the cherts at Rhynie, Aberdeenshire, Scotland. They are Rhynia gwynnevaughanii Kidston & Lang, Aglaophyton major D. S. Edwards, Horneophyton lignieri Barghoorn & Darrah, Asteroxylon mackiei Kidston & Lang, Nothia aphylla Lyon ex Høeg, Trichopherophyton teuchansii Lyon & Edwards and Ventarura lyonii Powell, Edwards & Trewin. The superb preservation of the silica permineralisations produced in the hot spring environment provides remarkable insights into the anatomy of early land plants which are not available from compression fossils and other modes of permineralisation. They include soft tissues, such as those surrounding stomata, rhizoids, apical and lateral meristems, and diversity in conducting cells, with inferences for palaeoecophysiology, including water use efficiency, transport and absorption, and for growth processes and patterns.
New gametophytes from the Early Devonian Rhynie chert
Authors: Kerp Hans , Trewin Nigel H. , Hass Hagen
Published: July 2007

Several new gametophytes are described from the Early Devonian Rhynie chert. The new monotypic genus Remyophyton, being the gametophyte of Rhynia, is represented by a dense stand of in situ preserved gametophytes with antheridia- and archegonia-bearing axes. The gametophytes are remarkably small in comparison to those of other Rhynie chert plants. The generic diagnoses of Lyonophyton and Langiophyton are emended to include archegonia- and antheridiabearing axes. All essential stages of the reproductive cycle, i.e. sporophytes, and male and female gametophytes, can now be demonstrated for three of the six land plants from the Rhynie chert, i.e. Rhynia gwynne-vaughanii, Aglaophyton major and Horneophyton lignieri.
Charophyte algae from the Rhynie chert
Authors: Kelman Ruth , Feist Monique , Trewin Nigel H. , Hass Hagen
Published: July 2007

The discovery of new specimens of Palaeonitella cranii (Kidston & Lang) Pia in the Early Devonian Rhynie chert permits the classification of this charophyte alga. This relatively small charophyte is composed of multicellular furcating branchlets with antheridia attached to the parent plant by a pedicel. The non-calcified gyrogonites, which are not seen in life position, are composed of six sinistrally spiralling cells and have six coronula cells arranged in a single layer around an apical pore.

Because the oogonia of P. cranii have six sinistrally spiralling cells and an apical pore, Palaeonitella has been assigned to the Palaeocharaceae. The shape and form of the oogonia is reminiscent of the extant Chareae, but the morphology of the thalli is indicative of the Nitelleae. This suggests that P. cranii, although retaining some characteristics of the Nitelleae, has some of the characteristics of the Chareae, supporting existing molecular studies which place the Nitelleae at the base of the Characeae.

Palaeonitella cranii inhabited the freshwater alkaline pools and streams which formed on sinter aprons created by hot spring activity. Extant charophytes exist in a similar environment (pH 8·66–8·9, temperature 25–30°C in summer) in pools and channels fed by hot springs in Yellowstone National Park, Wyoming, USA.
A new paradigm for granite generation
Authors: Vigneresse Jean Louis
Published: July 2007

Ideas about granite generation have evolved considerably during the past two decades. The present paper lists the ideas which were accepted and later modified concerning the processes acting during the four stages of granite generation: melting, melt segregation and ascent, and emplacement. The active role of the mantle constitutes a fifth stage.

Fluid-assisted melting, deduced from metamorphic observations, was used to explain granite and granulite formation. Water seepage into meta-sedimentary rocks can produce granitic melt by decreasing melting temperature. CO2 released by the mantle helps to transform rocks into granulites. However, dehydration melting is now considered to be the origin of most granitic melts, as confirmed by experimental melting. Hydrous minerals are involved, beginning with muscovites, followed by biotite at higher temperatures. At even deeper conditions, hornblende dehydration melting leads to calc-alkaline magmas.

Melt segregation was first attributed to compaction and gravity forces caused by the density contrast between melt and its matrix. This was found insufficient for magma segregation in the continental crust because magmas were transposed from mantle conditions (decompression melting) to crustal conditions (dehydration melting). Rheology of two-phase materials requires that melt segregation is discontinuous in time, occurring in successive bursts. Analogue and numerical models confirm the discontinuous melt segregation. Compaction and shear localisation interact non-linearly, so that melt segregates into tiny conduits. Melt segregation occurs at a low degree of melting.

Global diapiric ascent and fractional crystallisation in large convective batholiths have also been shown to be inadequate and at least partly erroneous. Diapiric ascent cannot overcome the crustal brittle-ductile transition. Fracture-induced ascent influences the neutral buoyancy level at which ascent should stop but does not. Non-random orientation of magma feeders within the ambient stress field indicates that deformation controls magma ascent.

Detailed gravity and structural analyses indicate that granite plutons are built from several magma injections, each of small size and with evolving chemical composition. Detailed mapping of the contact between successive magma batches documents either continuous feeding, leading to normal petrographic zoning, or over periods separated in time, commonly leading to reverse zoning. The local deformation field controls magma emplacement and influences the shape of plutons.

A typical source for granite magmas involves three components from the mantle, lower and intermediate crusts. The role of the mantle in driving and controlling essential crustal processes appears necessary in providing stress and heat, as well as specific episodes of time for granite generation. These mechanisms constitute a new paradigm for granite generation.
Origin of chemically zoned and unzoned cordierites from the South Mountain and Musquodoboit Batholiths, Nova Scotia
Authors: Erdmann Saskia , Clarke D. Barrie , MacDonald Michael A.
Published: July 2007

Textural relations and chemical zoning of cordierites in granites act as sensitive recorders of the conditions of their crystallisation history and underlying magma chamber processes. In this contribution, we present new data on texturally distinct and variably zoned cordierites from the late-Devonian, granitic South Mountain and Musquodoboit Batholiths, and infer the conditions of their formation. Using a combined textural (grain size, grain shape and inclusion relationships) and chemical (major element composition and compositional zoning) classification, we recognise the following six cordierite types: CG1/TT1, anhedral to subhedral macrocrysts with random inclusions and patchy normal zoning; CG2a/TT2, euhedral to subhedral macrocrysts with random inclusions and normal zoning; CG2b/TT2, euhedral to subhedral macrocrysts with random or oriented inclusions, and oscillatory zoning; CG3a/TT3, subhedral to euhedral microcrysts with no inclusions and reverse zoning; CG3b/TT4, euhedral macrocrysts with no inclusions and no zoning; and CG4/TT5, anhedral macrocrysts with random inclusions and normal zoning. The textural criteria suggest that these cordierites formed as a product of cotectic crystallisation from a melt, or as the result of a peritectic reaction involving country-rock material. The combined chemical and textural criteria suggest that: (1) normal zoning results from cotectic crystallisation during cooling, cotectic overgrowths on grains formed in a peritectic reaction with country-rock material, or cation exchange with a fluid; (2) oscillatory zoning results from cotectic crystallisation during variations in XMg of the silicate melt following magma replenishment; (3) reverse zoning results from crystallisation during pressure quenching; and (4) the unzoned cordierite results from cotectic crystallisation under fluid-rich conditions.
Growth of wedge-shaped plutons at the base of active half-grabens
Authors: Richards S. W. , Collins W. J.
Published: July 2007

Combined field and geophysical data show that plutons from the Bega Batholith are elongate, meridional, wedge-shaped bodies which intruded during a period of regional east–west extension in the Palaeozoic eastern Lachlan orogen, eastern Australia. Plutons within the core of the batholith have intruded coeval, syn-rift sediments and co-magmatic volcanics. The batholith is bound by high-temperature, dip-slip faults, and contains several major NE-trending transtensional faults which were active during batholith construction. In the central part of the batholith, the Kameruka pluton is an asymmetric, eastward-thickening, wedge-shaped body with the base exposed as the western contact, which is characterised by abundant, shallow-dipping schlieren migmatites which contain recumbent folds and extensional shear bands. A shallow (<30°), east-dipping, primary magmatic layering in the Kameruka pluton steepens progressively westward, where it becomes conformable to the east-dipping basal migmatites. The systematic steepening of the layering is comparable to sedimentary units formed during floor depression in syn-rift settings. The present authors suggest that the wedge-shaped plutons of the Bega Batholith are the deeper, plutonic expression of a hot, active rift. The batholith was fed and sustained by injection of magma through sub-vertical dykes. Displacement along syn-magmatic, NE-trending faults suggests up to 25 km of arc-perpendicular extension during batholith construction. The inferred tectonic setting for batholith emplacement is a continental back-arc, where modern half-extension rates of 20–40 mm yr−1 are not unusual, and are sufficient to emplace the entire batholith in ∼1 Ma. This structural model provides a mechanism for the emplacement of some wedge-shaped plutons and is one solution to the ‘room problem’ of batholith emplace
Assemblages of mammalian hair and blood-feeding midges (Insecta: Diptera: Psychodidae: Phlebotominae) in Miocene amber
Authors: Peñalver Enrique , Grimaldi David
Published: July 2007

Five new fossil species of the Recent genus of blood-feeding sand flies Lutzomyia (Psychodidae: Phlebotominae) are described: L. filipalpis, L. miocena, L. paleopestis, L. schleei, and L. succini. All are preserved in Miocene amber from the Dominican Republic; today Hispaniola harbours only two known species of this genus. Recent Lutzomyia feed on a wide variety of terrestrial vertebrates, including reptiles, birds, and mammals. Three rare pieces of the amber are reported, two described in detail, which preserved assemblages of Lutzomyia swarms with strands of mammalian hair, indicating that at least some of the fossil species were mammal feeders. Microstructure of the fossil hair offers little diagnostic evidence, but is very similar to that of insectivores in the Solenodontidae. Further preserved evidence indicates that the fossil midges swarmed about an arboreal nest or site of decayed wood that was worked by a mammal, but at very specific times during formation of the amber. Other very rare Dominican amber pieces containing a flea and an ixodid tick also contain mammalian hairs of similar microstructure, together with Lutzomyia sandflies, possibly reflecting the ectoparasite community of a Miocene mammal. This parasitic association has implications regarding the evolution of vectors of mammalian pathogens like Leishmania and the study further reveals the extent of palaeobiological inference that is possible with amber.
Late Carboniferous scavenging ostracods: feeding strategies and taphonomy
Authors: Wilby Philip R. , Wilkinson Ian P. , Riley Nicholas J.
Published: July 2007

Direct fossil evidence of scavenging ostracods is rare. A convincing example, representing the earliest recorded occurrence of ostracods feeding on vertebrate carrion, is described from the Bowland Shale Formation (Kinderscoutian, Upper Carboniferous) of Derbyshire, UK. It consists of the anterior end of a shark (Orodus sp.) whose upper surface is crowded with adults and juveniles of the nektobenthic ostracod Eocypridina carsingtonensis Wilkinson, Williams, Siveter & Wilby, 2004 (Myodocopida: Cypridinidae). Extrapolation of their preserved density suggests that the entire carcass may have hosted over a thousand individuals. It presented a rare opportunity for benthic scavenging in the Widmerpool Gulf because it was sufficiently large to have protruded above the inhospitable, and probably soupy, substrate surface. Although not necessarily a necrophagous specialist, E. carsingtonensis appears to have been well adapted to rapidly locating and exploiting widely dispersed nekton food drops. Its absence from the background sediment suggests that it commuted to the shark over relatively large distances, probably from adjacent basin highs. This implies a well-developed chemosensory capability. The ostracods are interpreted as having been overwhelmed by sediment dislodged during the sudden collapse of the partially buried carcass.
A reassessment of the temnospondyl amphibian Perryella olsoni from the Lower Permian of Oklahoma
Authors: Ruta Marcello , Bolt John R.
Published: July 2007

Additional mechanical preparation of the type material of the temnospondyl amphibian Perryella olsoni (Lower Permian, Wellington Formation, Oklahoma) highlights new cranial and postcranial features and provides additional data on previously known structures. Important new information is available for the quadrate, palatal bones and their associated dentition, parasphenoid, and appendicular skeleton. The revised diagnosis and redescription of Perryella provide the basis for a re-evaluation of its systematic affinities. A cladistic analysis of (mostly) Carboniferous and Permian temnospondyls, together with several Devonian and Carboniferous stem tetrapod outgroups, supports a single origin for temnospondyls. The sequence of branching events within temnospondyls consists of: (1) a paraphyletic Edopoidea; (2) a clade of Zatracheidae, Eryopidae, and basal Archegosauriformes; (3) a monophyletic Dvinosauria; and (4) a monophyletic Dissorophoidea. Perryella is nested within Dvinosauria in an intermediate position between Trimerorhachidae and Dvinosauroidea.
Spore assemblages from the Lower Devonian ‘Lower Old Red Sandstone’ deposits of the Rhynie outlier, Scotland
Authors: Wellman Charles H.
Published: July 2007

Since the late 1980s an extensive programme of trenching/borehole drilling has been undertaken in order to study the Lower Devonian ‘Lower Old Red Sandstone’ deposits of the Rhynie outlier in the Grampian Highlands of Scotland. The boreholes have provided new information on the stratigraphical succession and geological structure of the Rhynie outlier, both of which were hitherto poorly understood due to the paucity of good surface exposure and the complex geological relationships of the deposits. One hundred and eighteen palynological samples were collected, representing much of the stratigraphical sequence of the inlier, of which 106 were productive. Productive samples yield assemblages of well preserved palynomorphs, dominated by spores and phytodebris, but also containing arthropod cuticle and rare freshwater algal remains. The spore assemblages are systematically described and two new genera and six new species proposed. They are similar throughout the sequence and the spores belong to the polygonalis–emsiensis Spore Assemblage Biozone of Richardson & McGregor (1986) and the PoW Oppel Zone (possibly Su Interval Zone) of Streel et al. (1987), indicating an early (but not earliest) Pragian–?earliest Emsian age range, that may possibly be restricted to latest Pragian–?earliest Emsian. The palynomorph assemblages contain only terrestrial forms, supporting sedimentological interpretation of the deposits as ‘Lower Old Red Sandstone’ fluviatile and lacustrine deposits, with occasional extrusive volcanics and volcaniclastic sediments intercalated. The palynomorphs are of variable thermal maturity (within and between samples), probably reflecting differential heating associated with the complex volcanic/hydrothermal system. The new palynological data provide, for the first time, a reliable biostratigraphical age for the deposits, and suggest that they accumulated relatively rapidly. Spore biostratigraphy and thermal maturity studies facilitate correlation of the tectonically complex deposits, and shed light on other aspects of the geological history of the outlier. The palynomorph assemblages also aid interpretation of the biota of the Rhynie basin, including the exceptionally preserved biotas of the Rhynie and Windyfield cherts.
Evidence for late Hesperian lacustrine activity in Shalbatana Vallis, Mars
Authors: Di Achille Gaetano , Ori Gian Gabriele , Reiss Dennis
Published: July 2007

An intravalley paleolake (more than 400 m deep) was detected along the course of Shalbatana Vallis from the evidence of shorelines and the occurrence of a few fan‐delta deposits (including a Gilbert‐type delta). The fronts of all the sedimentary deposits strikingly match the same topographic contours (2800 and 3000 m below the Martian datum), indicating the paleolake water levels under which they formed. Also, the corresponding shorelines are visible along the Shalbatana Vallis walls. The peculiar settings of the lake suggest that Shalbatana Vallis was impounded during its final hydrological activity and that ponding of water lasted enough time to allow the formation and evolution of the lacustrine system. Water source is uncertain, but a composite sapping mechanism is hypothesized in order to take into account the amount of water required to excavate, transport, and deposit the materials found in the deposits. Previous works and new crater counting computations indicate that the paleolake was active during the Hesperian epoch; therefore, at that time, surface conditions were different from those of modern Mars and supportive of flow and ponding of water. It is unclear whether the hydrological activity was sustained entirely by a favorable climatic regime and secondary regional factors like volcanism, impact cratering, and tectonism could have also triggered/accelerated the local groundwater activity, implying that the system could have evolved relatively independent from climatic conditions. The latter eventuality and the regional importance of this research advised against an extrapolation of its results to the overall debate about Martian climatic‐geomorphological evolution.
Phyllosilicates in the Mawrth Vallis region of Mars
Authors: Loizeau D. , Mangold N. , Poulet F. , Bibring J.‐P. , Gendrin A. , Ansan V. , Gomez C. , Gondet B. , Langevin Y. , Masson P. , Neukum G.
Published: July 2007

OMEGA/Mars Express has discovered large outcrops rich in phyllosilicates in the region of Mawrth Vallis, Mars (around 20°W, 25°N). The region is located in Noachian highly cratered terrains, close to the limit of the Martian dichotomy, where the outflow channel Mawrth Vallis cuts the highlands. We have examined this region using OMEGA spectra of the surface from 0.9 μm to 2.6 μm, with spatial sampling from 500 m to 3 km, offering a full coverage of the region. OMEGA spectra show two broad bands centered at 1 μm and 2.2 μm, revealing the presence of clinopyroxene on dark surfaces. Phyllosilicates have been identified by absorption bands at 1.4 μm, 1.9 μm, and 2.2 or 2.3 μm. Comparison with laboratory spectra reveals similarities with Al‐OH smectites such as montmorillonites, or Fe‐ or Mg‐OH smectites such as nontronite. A precise location of the phyllosilicate‐rich areas on visible HRSC images indicates that they are placed exclusively on bright outcrops, mostly on the plateaus, dated to the Noachian period. On HRSC and MOC images the phyllosilicate‐rich outcrops reveal strong erosional features such as numerous residual buttes composed of layers a few meters thick. The phyllosilicate‐rich unit corresponds to a geological unit more than 100 m thick, over a horizontal extension approximately of 300 km × 400 km. This unit implies a large volume of altered rocks, either in situ or after transport and deposition, in Noachian terrains, revealing a different climatic and geologic environment from the present one.